Shock absorber

Description of the invention

The present invention relates to a damper and a damper assembly, in particular a damper and damper assembly for motor vehicles, but the invention is not limited thereto.

Commonly available hydraulic shock absorbers for vehicles are most often telescopic in structure, consisting of a single piston and cylinder system used in conjunction with a coil spring around the shock absorber. The piston rod is connected to a piston inside the cylinder with its free end protruding from the cylinder to engage the vehicle body. The cylinder is attached to the vehicle wheel suspension. The stretching or compression of the shock absorber, which occurs as the wheel suspension passes over the uneven surface to elastically deform the coil spring, is damped by the resistance of the piston moving inside the oil-filled cylinder. The damping resistance of the piston is provided by any of a variety of forms of valve mechanism in the piston that restricts oil flow within the cylinder from one side of the piston to the other.

The damping characteristic can be adjusted to some extent by adjusting the valve mechanism in the piston. Gas shock absorbers are also available which have the same basic structure as described above but are further provided with a gas chamber at the end of the cylinder remote from the piston rod and separated from the oil filled chamber by a movable distributor piston. The gas pressure in the gas chamber can be adjusted to achieve the damping characteristics of the damper.

These currently available shock absorbers have certain operational limitations, e.g., adjustment limits to ensure accurate damping in certain ranges of amplitude and duration / frequency of wheel suspension movement. The ride quality provided by such shock absorbers also usually compromises the ride quality.

Hence, there is a need for an improved damper and damper assembly.

The invention provides a shock absorber comprising a first cylinder having a first piston chamber filled with liquid and sealed against the environment, a first piston disposed in the first piston chamber and axially displaceable therein, a first damping means in the form of a valve mechanism for damping the axial movement of the first piston in the first piston chamber. a second cylinder coaxial with the first cylinder, both of the first and second cylinders, are axially opposite and mutually axially displaceable, the shock absorber having means for securing these cylinders to the body and the wheel suspension of the vehicle, respectively, characterized in that the second cylinder has a second piston chamber filled with liquid and sealed against the environment, a second piston arranged in the second piston chamber and axially displaceable in it, a second damping means in the form of a valve mechanism for damping the axial movement of the second piston in the second piston chamber and a piston rod extending axially between and into the first and second piston chambers, the pistons being mounted on the two axial ends of the piston rod, respectively.

Preferably, at least one of the first and second cylinders, at one of their ends remote from the piston rod, is provided with a closed gas chamber, the piston chambers of the gas chambers being separated by an axially displaceable dividing piston.

Each of the at least one gas chamber is provided with a valve for regulating the pressure therein.

In a preferred embodiment of this damper, each of the at least one gas chamber is positioned outside the respective cylinder, the gas chamber being arranged in a separate gas cylinder containing the dividing piston, the respective piston chamber being connected to the gas cylinder. by means of a conduit at the distal end of the corresponding cylinder.

Preferably, the damper has first and second helical springs, the first helical spring being associated with the first cylinder and having a first end attached and axially located with respect to the piston rod and a second end attached and axially fixed with respect to the first cylinder, and a second helical spring associated with the second cylinder and has a first end secured and axially fixed with respect to the piston eye and a second end fixed and axially fixed with the second cylinder.

According to a further embodiment of the invention, the first ends of the first and second helical springs are fixed and axially fixed with respect to the piston rod by means of an annular thrust plate attached to the piston rod between the first and second cylinders.

PL 193 377 B1

In a preferred embodiment, the shock absorber comprises a sleeve extending between the first and second cylinders, the sleeve being sealed to the first and second cylinders to form a sleeve recess therebetween, the sleeve being telescopically displaceable with respect to at least one of the first cylinders. and the second, allowing the relative axial displacement of the first and second cylinders.

Preferably, the sleeve is provided with a valve for regulating the pressure within the sleeve cavity.

Further preferably, the sleeve is axially displaceable with respect to both the first and second cylinders.

In a further embodiment of the damper, a first annular recess is formed in the area of ​​the overlap between the first cylinder and the sleeve, the opposing axial ends thereof being respectively formed by a first annular seal attached to the first cylinder and cooperating with the sleeve and a second annular seal attached to the sleeve and cooperating with the sleeve. first cylinder.

Preferably, the first annular recess is connected to the first piston chamber, the cross-sectional area of ​​the first annular recess, measured in a plane perpendicular to the longitudinal axis of the piston rod, substantially equal to the cross-sectional area of ​​the piston rod.

The first annular cavity is, in another embodiment, provided with a valve for regulating the gas pressure therein.

According to another embodiment of the damper, a second annular recess is formed in the area of ​​the overlap between the second cylinder and the sleeve, the opposite axial ends thereof being respectively formed by a first seal attached to the second cylinder and cooperating with the sleeve and a second seal attached to the sleeve and co-operating with the sleeve. working with the second cylinder.

Preferably, the second annular recess is connected to the second piston chamber, the cross-sectional area of ​​the second annular recess, measured in a plane perpendicular to the longitudinal axis of the piston rod, substantially equal to the cross-sectional area of ​​the piston rod.

Preferably, the second annular cavity is provided with a valve for regulating the gas pressure therein.

In a preferred embodiment of the invention, the damper has first and second helical springs, the first helical spring being associated with the first cylinder and having a first end secured and axially fixed with respect to the sleeve and a second end secured and axially fixed with respect to the first cylinder. a second coil spring is associated with the second cylinder and has a first end secured and axially fixed with respect to the sleeve and a second end fixed and axially fixed with respect to the second cylinder.

Preferably, the first ends of the first and second helical springs are fixed and axially fixed to the sleeve by an annular thrust plate secured to the sleeve between the first and second cylinders.

The shock absorber assembly according to the invention comprises a first shock absorber and a second shock absorber, each comprising a first cylinder having a liquid filled and sealed first piston chamber, a first piston disposed in the first piston chamber and axially displaceable therein, a first damping means in the form of a mechanism. valve for damping the axial displacement of the first piston in the first piston chamber, a second cylinder coaxial with the first cylinder, the first and second cylinders both being axially opposite and mutually axially displaceable, the shock absorber having means for securing the cylinders to the body and the wheel suspension of the vehicle, respectively, characterized by that the first and second shock absorbers each comprise a second cylinder having a second piston chamber filled with liquid and sealed to the surroundings, a second piston disposed in the second piston chamber and displaceable axially therein, a second damping means in the form of a valve mechanism for damping the axial movement of the second piston in the second piston chamber and a piston rod axially extending between and into the first and second piston chambers, the first pistons being and the second are mounted on the first and second axial ends of the piston rod, respectively, and include a sleeve extending between the cylinders, the first and second cylinders, the sleeve cooperating tightly with the first and second cylinders to form a sleeve recess therebetween, the sleeve being telescopically displaceable with respect to at least one of the first and second cylinders, allowing the relative axial movement of the first and second cylinders.

And the second, wherein a first annular recess is formed in the area of ​​the overlap between the first cylinder and the sleeve, the opposing axial ends thereof being respectively formed by a first annular seal attached to the first cylinder and cooperating tightly with the sleeve and a second annular seal attached to it. to the sleeve and working tightly with the first cylinder, the first annular cavity of the first shock absorber is filled with liquid and operatively associated with the sleeve cavity of the second shock absorber, wherein in a reduced / enlarged state of the first annular cavity of the first shock absorber, the gas pressure in the sleeve cavity of the second shock absorber is increased / decreased.

Preferably, the first annular cavity of the first shock absorber is connected to the first end of the control cylinder and the sleeve cavity of the second shock absorber is connected to the second end of the control cylinder, and a piston separating the control cylinder is disposed inside the control cylinder, isolating the first annular cavity of the first shock absorber and the sleeve cavity of the second. shock absorber.

Preferably, the piston separating the control cylinder is provided with a piston rod sealingly engaging the reduced cross section portion of the control cylinder towards the first end of the control cylinder such that the projecting end of the piston rod isolates the first annular cavity of the first shock absorber.

In a preferred embodiment of the invention, the first annular cavity of the second shock absorber is filled with liquid and is operatively associated with the sleeve cavity of the first shock absorber, wherein in a reduced / enlarged volume condition of the first annular cavity of the second shock absorber, the gas pressure in the sleeve cavity of the second shock absorber is increased / reduced. .

A further shock absorber according to the invention comprises a cylinder having a first end, a second end and a piston chamber extending between the first cylinder end and the second cylinder end, the piston chamber being subdivided into a liquid filled first piston chamber extending towards the first cylinder end and filled with the liquid, the second piston chamber extending towards the other end of the cylinder, a first piston disposed in the first piston chamber and displaceable axially therein, a first damping means for damping the axial displacement of the first piston in the first piston chamber, a first piston rod extending from the first cylinder end, the first piston mounted on the end of the first piston rod, the second piston disposed in the second piston sub-chamber and axially displaceable in it, a second damping means for damping the axial displacement of the second piston in the second piston sub-chamber, a second piston rod extending from the second cylinder end, the second piston being mounted on the end of the second piston rod, and means for securing the first and second piston rods to the vehicle body and wheel suspension, respectively characterized by having a closed gas chamber which is insulated against the flow of fluid from / to the first and second piston sub-chambers, by axially displaceable dividing pistons.

Preferably, the dividing pistons and the gas chamber are located in the cylinder, the dividing pistons and the gas chamber separating the first and second sub-chambers.

Preferably, the gas chamber is provided with a valve for regulating the gas pressure therein.

In an advantageous embodiment of the invention, the piston chamber is divided into first and second piston chambers by means of a fixed partition, the first and second piston chambers being connected to opposite ends of the gas cylinder by first and second lines adjacent to the constant. baffles, in the first and second piston sub-chambers, respectively, the gas chamber and the dividing pistons being located in the gas cylinder.

Preferably, the damper has first and second helical springs, the first helical spring being associated with the first piston rod and having a first end attached and axially located with respect to the cylinder and a second end attached and axially located with respect to the first piston rod, and a second helical spring is associated with the second piston rod. and has a first end secured and axially fixed with respect to the cylinder and a second end fixed and fixed axially with the second piston rod.

Preferably, the first ends of the first and second helical springs are attached and axially fixed to the cylinder by means of an annular thrust plate attached to the cylinder.

In a preferred embodiment of the invention, the shock absorber comprises a first sleeve telescopically positioned around and engaging the cylinder and extending from the first end of the cylinder, the distal end of the first sleeve being closed so that the first sleeve forms a closed first sleeve recess, the first piston rod being fixed. relative to the first sleeve.

PL 193 377 B1

Preferably, the first sleeve is provided with a valve for regulating the gas pressure within the first sleeve cavity.

Preferably, a first annular recess is formed in the area of ​​the overlap between the cylinder and the first sleeve, the opposing axial ends thereof being respectively formed by a first annular seal attached to the cylinder and cooperating with the first sleeve and a second annular seal attached to the first sleeve and cooperating with the cylinder.

In a preferred embodiment of the invention, the first annular cavity is connected to the first piston chamber, the cross-sectional area of ​​the first annular cavity, measured in a plane perpendicular to the longitudinal axis of the first piston rod, substantially equal to the cross-sectional area of ​​the first piston rod.

Preferably, the first annular cavity is provided with a valve for regulating the gas pressure therein. Preferably, the shock absorber comprises a second bushing telescopically extending around and engaging the cylinder and extending from the second end of the cylinder, the distal end of the second sleeve being closed so that the second sleeve forms a closed second sleeve recess, the second piston rod being fixed relative to the second sleeve.

In a preferred embodiment of the invention, the second sleeve is provided with a valve for regulating the gas pressure inside the second sleeve cavity.

Preferably, a second annular recess is formed in the area of ​​the overlap between the cylinder and the second sleeve, the opposing axial ends thereof being respectively formed by a first seal attached to the cylinder and cooperating with the second sleeve and a second seal attached to the second sleeve and cooperating with the cylinder.

Preferably, the second annular recess is connected to the second piston sub-chamber, the cross-sectional area of ​​the second annular recess, measured in a plane perpendicular to the longitudinal axis of the second piston rod, substantially equal to the cross-sectional area of ​​the second piston rod.

In a preferred embodiment of the invention, the second annular cavity is provided with a valve for regulating the gas pressure therein.

The shock absorber assembly according to the invention comprises a first shock absorber and a second shock absorber, each comprising a cylinder having a first end, a second end and a piston chamber extending between the first cylinder end and the second cylinder end, the piston chamber being subdivided into a liquid-filled first sub-chamber. a piston, extending towards the first end of the cylinder, and a liquid-filled second piston chamber, extending towards the second cylinder end, a first piston disposed in and axially displaceable therein, a first damping means for damping the axial displacement of the first piston in the first piston chamber, a first piston rod extending from the first cylinder end, the first piston being mounted on the end of the first piston rod, the second piston located in the second piston sub-chamber and axially displaceable therein, a second damping means for damping the axial displacement of the second piston in the second piston sub-chamber, a second piston rod extending from the second cylinder end, the second piston being mounted on the end of the second piston rod, and means for securing the first and second piston rods to the vehicle body and wheel suspension, respectively characterized in that each of these shock absorbers, the first and the second, has a closed gas chamber, which is insulated from fluid flow from / to the first and second piston sub-chambers by axially displaceable dividing pistons, comprising a first sleeve telescopically extending around and sealingly engaging the cylinder and extending from the first cylinder end, the distal end of the first sleeve being closed such that the first sleeve forms a closed first sleeve recess, the first piston rod being fixed with respect to the first sleeve, a first annular recess is formed in the area of ​​the overlap between the cylinder and the first sleeve, the opposing axial ends thereof being respectively formed by a first annular seal attached to the cylinder and cooperating tightly with the first sleeve and a second annular seal attached to the first sleeve and cooperating tightly with cylinder, the first annular cavity of the first shock absorber is filled with liquid and operatively associated with the first sleeve cavity of the second shock absorber, wherein in the reduced / enlarged volume condition of the first annular cavity of the first shock absorber, the gas pressure in the first sleeve cavity of the second shock absorber is increased / decreased.

PL 193 377 B1

Preferably, the first annular cavity of the first shock absorber is connected to the first end of the control cylinder and the first sleeve cavity of the second shock absorber is connected to the second end of the control cylinder, and a piston separating the control cylinder is disposed within the control cylinder, isolating the first annular cavity of the first shock absorber and the first sleeve cavity. the second shock absorber.

Preferably, the piston separating the control cylinder is provided with a piston rod sealingly engaging the reduced cross section portion of the control cylinder towards the first end of the control cylinder such that the projecting end of the piston rod isolates the first annular cavity of the first shock absorber.

In a preferred embodiment of this damper assembly, the first annular cavity of the second damper is filled with liquid and is operatively connected to the first tube cavity of the first damper, with the reduced / enlarged volume of the first annular cavity of the second damper, the gas pressure in the first cavity. sleeve of the first shock absorber is increased / decreased.

Moreover, according to the invention, a further shock absorber comprises a cylinder having a first end, a second end and a liquid-filled piston chamber extending between the first cylinder end and the second cylinder end, the piston chamber being sealed to the surroundings, the first piston disposed in the first piston chamber towards the first. end of the cylinder and axially displaceable in it, a second piston disposed in the second piston chamber towards the second cylinder end and displaceable axially therein, a first damping means for damping the flow of liquid through the first piston between a first piston chamber area formed between the first cylinder end and the first piston and a second piston chamber area formed between the first piston and the second piston, a first piston rod extending from the first cylinder end, a first piston is mounted at the end of the first piston rod, a second damping means for damping the flow of liquid through the second piston between a second piston chamber area and a third piston chamber area formed between the second piston and a second cylinder end, a second piston rod extending from the second cylinder end, a second piston is mounted at the end of the second piston rod, volume-compensation means formed in or connected to the piston chamber, to maintain the effective volume of the piston chamber by receiving the liquid displaced after the first and second piston rods have been inserted into the piston chamber after the first and second pistons have been axially displaced, and means for securing the first and second piston rods to the vehicle body and wheel suspension, respectively, characterized in that, in addition to the fluid flow communication provided by the damping means, the first and second piston chamber regions, the first, the second and third are insulated against fluid flow.

Preferably, the damper has first and second helical springs, the first helical spring being associated with the first piston rod and having a first end attached and axially located with respect to the cylinder and a second end attached and axially located with respect to the first piston rod, and the second helical spring is associated with the second piston rod. and has a first end secured and axially fixed with respect to the cylinder and a second end fixed and fixed axially with the second piston rod.

Preferably, the first ends of the first and second helical springs are attached and axially fixed to the cylinder by means of an annular thrust plate attached to the cylinder.

In a preferred embodiment of the invention, the shock absorber comprises a first sleeve telescopically positioned around and engaging the cylinder and extending from the first end of the cylinder, the distal end of the first sleeve being closed so that the first sleeve forms a closed first sleeve recess, the first piston rod being fixed. relative to the first sleeve.

Preferably, the first sleeve is provided with a valve for regulating the gas pressure within the first sleeve cavity.

Preferably, a first annular recess is formed in the area of ​​overlap between the cylinder and the first sleeve, the opposing axial ends thereof being respectively formed by a first annular seal attached to the cylinder and cooperating tightly with the first sleeve and a second annular seal attached to the first sleeve and engaging tightly with the cylinder. .

In a preferred embodiment of the invention, the first annular cavity is provided with a valve for regulating the gas pressure therein.

PL 193 377 B1

Preferably the shock absorber has a second bushing telescopically extending around and engaging the cylinder tightly and extending from the second end of the cylinder, the distal end of the second sleeve being closed so that the second sleeve forms a closed second sleeve recess, the second piston rod being secured and fixed relative to the second sleeve.

Preferably, the second sleeve is provided with a valve for regulating the gas pressure within the second sleeve cavity.

In a preferred embodiment of the invention, a second annular recess is formed in the area of ​​the overlap between the cylinder and the second sleeve, the opposite axial ends thereof being respectively formed by a first seal attached to the cylinder and cooperating with the second sleeve and a second seal attached to the second sleeve and cooperating with the second sleeve. cylinder.

Preferably, the second annular cavity is provided with a valve for regulating the gas pressure therein.

In addition, according to the invention, a further set of shock absorbers comprising a first shock absorber and a second shock absorber, each comprising a cylinder having a first end, a second end and a liquid-filled piston chamber extending between the first cylinder end and the second cylinder end. wherein the piston chamber is sealed to the surroundings, a first piston disposed in the first piston chamber towards the first cylinder end and axially displaceable therein, a second piston located in the second piston chamber towards the second cylinder end and displaceable axially therein, the first piston means for arranging the flow of liquid through the first piston between the first piston chamber area formed between the first cylinder end and the first piston and the second chamber area a piston rod formed between the first piston and the second piston, a first piston rod extending from the first cylinder end, a first piston is mounted at the end of the first piston rod, a second damping means for damping the flow of liquid through the second piston between a second piston chamber area and a third piston chamber area formed between the second piston and a second cylinder end, a second piston rod extending from the second cylinder end, a second piston is mounted at the end of the second piston rod, volume-compensation means formed in or connected to the piston chamber, to maintain the effective volume of the piston chamber by receiving the fluid displaced after the first and second piston rods have been inserted into the piston chamber after the first and second pistons have been axially displaced, and means for securing the first and second pistons to the vehicle body and wheel suspension, respectively characterized in that each of these shock absorbers, the first and the second, comprises a first sleeve telescopically extending around and engaging the cylinder and extending from the first end of the cylinder, the distal end of the first sleeve being closed such that the first sleeve forms a closed first sleeve recess, the first piston rod being fixed with respect to the first sleeve, apart from the fluid flow connection provided by the damping means, first and second piston chamber regions, first, second and third, are insulated against fluid flow, the first annular cavity of the first shock absorber is filled with liquid and operatively associated with the first sleeve cavity of the second shock absorber, and in a reduced / enlarged volume condition of the first annular cavity of the first shock absorber, the gas pressure in the first sleeve cavity of the second shock absorber is increased / decreased.

Preferably, the first annular cavity of the first shock absorber is connected to the first end of the control cylinder, the first sleeve cavity of the second shock absorber is connected to the second end of the control cylinder, and a piston separating the control cylinder is disposed within the control cylinder, isolating the first annular cavity of the first shock absorber and the first cavity. sleeve of the second shock absorber.

Preferably, the piston separating the control cylinder is provided with a piston rod sealingly engaging the reduced cross section portion of the control cylinder towards the first end of the control cylinder such that the projecting end of the piston rod isolates the first annular cavity of the first shock absorber.

In a preferred embodiment of the damper assembly, the first annular cavity of the second damper is filled with liquid and is operatively associated with the first sleeve cavity of the first damper, and in a reduced / enlarged state of the first annular cavity of the second damper, the gas pressure in the first sleeve cavity of the second damper is increased / reduced.

PL 193 377 B1

A further shock absorber according to the invention comprising a cylinder having a liquid-filled piston chamber, an axially displaceable piston disposed in the piston chamber, means for damping the axial displacement of the piston through the liquid in the piston chamber, a piston rod connected to the piston and extending from the first end of the cylinder, means for securing one of the elements. the sleeve and cylinder for the vehicle body and the other of the sleeve and cylinder for the suspension of the vehicle wheel, a sleeve positioned telescopically around the cylinder and cooperating tightly therewith and extending from the first end of the cylinder, the distal end of the sleeve being closed so that the sleeve forms a sleeve recess, the piston rod being fixed with respect to the sleeve, characterized in that the sleeve recess it's closed.

Preferably, the sleeve is provided with a valve for regulating the gas pressure inside the sleeve cavity.

Preferably, an annular recess is formed in the area of ​​the overlap between the cylinder and the sleeve, the opposite axial ends thereof being respectively formed by a first seal attached to the cylinder and cooperating with the sleeve and a second seal attached to the sleeve and cooperating with the cylinder.

In a preferred embodiment, the annular recess is connected to the piston chamber, the cross-sectional area of ​​the annular recess, measured in a plane perpendicular to the longitudinal axis of the piston rod, substantially equal to the cross-sectional area of ​​the piston rod.

Preferably, the annular cavity is provided with a valve for regulating the gas pressure therein.

Furthermore, a further damper assembly according to the invention comprises a first damper and a second damper, each including a cylinder having a liquid-filled piston chamber, an axially displaceable piston disposed in the piston chamber, means for damping the axial displacement of the piston through the liquid in the piston chamber, the piston rod connected to piston and protruding from the first end of the cylinder, means for securing one of the bushing and cylinder to the vehicle body and the other of the bushing and the cylinder for suspension of the vehicle wheel, a bushing telescopically disposed around and sealingly engaging the cylinder and extending from the first end of the cylinder, the distal end of the bushing is closed so that the sleeve forms a sleeve cavity, the piston rod being fixed with respect to the sleeve, characterized in that each of these shock absorbers, the first and the second have a closed sleeve recess, an annular recess in the area of ​​overlap between the cylinder and the sleeve, the opposite axial ends thereof being respectively formed by a first seal attached to the cylinder and cooperating with the sleeve, and a second seal attached to the sleeve and cooperating with the sleeve. cylinder, the annular cavity of the first shock absorber is filled with liquid and is operatively associated with the sleeve cavity of the second shock absorber, wherein in the reduced / increased volume condition of the first damper annular cavity, the gas pressure in the sleeve cavity of the second damper is increased / decreased.

Preferably, the annular cavity of the first damper is connected to the first end of the control cylinder and the sleeve cavity of the second damper is connected to the second end of the control cylinder, the control cylinder separating piston being disposed inside the control cylinder, insulating the annular cavity of the first damper and the sleeve cavity of the second damper.

Preferably, the piston separating the control cylinder is provided with a piston rod sealingly engaging the reduced cross section portion of the control cylinder towards the first end of the control cylinder such that the projecting end of the piston rod isolates the annular cavity of the first shock absorber.

In a preferred embodiment, the annular cavity of the second shock absorber is filled with liquid and is operatively associated with the sleeve cavity of the first shock absorber, wherein in the reduced / enlarged volume condition of the annular cavity of the second shock absorber, the gas pressure in the sleeve cavity of the first shock absorber is increased / reduced.

The subject matter of the invention is illustrated in the drawings in which fig. 1 shows the shock absorber according to the first embodiment in a stretched longitudinal section, fig. 2 - the shock absorber of fig. 1 in a compressed state, in a longitudinal section, fig. 1a - the shock absorber according to the first embodiment in a stretched longitudinal section, fig. 2a - the shock absorber of fig. 1a in a compressed longitudinal section, fig. 3 - a damper according to a further version of the first embodiment in a stretched state, in longitudinal section, Fig. 4 - damper

Fig. 5 shows the shock absorber according to the second embodiment in a stretched longitudinal section in a longitudinal section of the modified first embodiment, Fig. 6 - a shock absorber according to the first example in a compressed state, longitudinal section, Fig. 7 - damper according to the modified second example in a stretched longitudinal section, fig. 8 - alternative embodiment of the damper of fig. 3 Fig. 9 - alternative example of the damper of Fig. 7 in a stretched longitudinal section, Fig. 10 - modified example of the damper of Fig. 1 in a stretched longitudinal section, Fig. 11 - in a longitudinal section stretched longitudinally. a modified example of the damper of Fig. 5 in a stretched longitudinal section, Fig. 12 - a damper according to a further modified second embodiment in a compressed longitudinal section, Fig. 13 - the shock absorber of Fig. 12 in a stretched state, longitudinal section, Fig. 14 - the shock absorber of the third embodiment in a longitudinal section, in a stretched state, Fig. 15 - the shock absorber of Fig. 14 in a compressed state, in cross section. 16 - modified embodiment of the damper of fig. 7 in a compressed state, longitudinal section, fig. 17 - damper of fig. 16 in a stretched state, longitudinal section, fig. 18 - two operatively connected shock absorbers according to fig. 12, in longitudinal section, fig. 19 - unit similar to the unit of fig. 18, in longitudinal section, fig. 20 - unit similar to the unit of fig. 19, but using 16, longitudinal sectional view, FIG. 21, modified embodiment of the damper of FIG. 14 in a stretched state, longitudinal section, FIG. 22, the damper of FIG. 21 in a compressed state, longitudinal section, FIG. 23 Fig. 16 - modified embodiment of the damper of Fig. 16 in compressed state, longitudinal section, Fig. 24 - damper of Fig. 23 in extended condition, longitudinal section, Fig. 25 - McPherson type version of the damper of Fig. 23 in a pressurized state. In this way, in longitudinal section, Fig. 26 shows a shock absorber similar to that in Fig. 25, in a stretched state, in longitudinal section.

Figures 1 and 2 show the shock absorber according to the first embodiment in a stretched and compressed state. The shock absorber is equipped with two coaxial first and second cylinders 11,21. Each cylinder has a piston chamber 12, 22 which is filled in a known manner with oil, hydraulic fluid or other suitable fluid. In each of the first and second piston chambers 12, 22, there is an axially displaceable piston 13, 23 with damping means for damping the axial movement of the pistons 13, 23 through the fluid in the respective piston chambers 12, 22.

The damping agent may take any suitable form known in the art. A typical damping means may be the normal valve mechanism 14, 24 in the pistons 13, 23, which is one or more holes 14a, 24a extending axially through the piston 13, 23, and a series of flexible thin plates 14b, 24b attached to the axial ends of the piston. which at least partially cover the opening (s) 14a, 24a to restrict or block oil flow through the opening (s). The deformation of the plates away from the opening (s) as a result of the fluid pressure allows the fluid to pass through the openings.

Between the first and second cylinders 11, 21, there is an axial piston rod 1 extending into the piston chambers 12, 22 in the first and second cylinders. The first and second axial ends 1a, 1b of the piston rod 1 are connected to the first and second pistons 13, 23, respectively, in a known manner.

A means for securing the cylinders in the form of a threaded pin 15 extends from the upper, i.e. distal end 11a of the first cylinder, remote from the piston rod 1, for fixing the first cylinder in a known manner to a mounting point on the vehicle body (not shown). To adapt to the particular vehicle, other means could also be used to fix the first cylinder. A means for securing the cylinders in the form of a bearing 25 is provided at the lower or distal end 21a of the second cylinder 21, intended to attach the second cylinder to the suspension of a vehicle wheel (not shown) in a known manner. Again, the means for securing the second cylinder may be of any form suitable for the particular wheel suspension.

Each of the proximal ends 11b, 21b of the cylinders is provided with an end portion and a guide with a seal 19, 29 for sealing the ends of the piston chambers at the entry point to the eye 1.

In connection with the damper, a coil spring can be used in a known manner.

The shock absorber according to the first embodiment is thus generally in the form of two opposite conventional shock absorbers connected by their piston rods. Having two pistons to provide damping in a single damper increases the available damping in a given damper and halves the stroke of each piston and rod. This ensures a lowered operating temperature and pressure, and an extended service life of the shock absorber. It is also possible to do this effectively

Even for small amplitude and short duration wheel movements. The double piston design also allows the damper to damp 50% to 100% higher frequencies than the single piston design. It is also possible to increase the total surface area of ​​the piston by up to 100% compared to a single piston shock absorber with the same cylinder diameter.

While in a typical single piston damper the moving piston is directly connected to the vehicle, the described double piston damper isolates the moving pistons from both the vehicle body and wheel suspension via oil inside the piston chambers. This isolation and the reduction of the amplitude of displacements provide the vehicle occupants with a higher level of driving comfort.

The provision of two pistons also allows the adjustment of the two valve mechanisms so that increased adjustment of the damping characteristics is possible. In addition, the valve mechanisms can be adjusted to provide individually different characteristics by tuning the damper to two distinct ranges of wheel vibration / displacement. Such a two-range tuning could be particularly beneficial on rally cars that can run on rough dirt roads and asphalt in one race stage, requiring different shock absorber characteristics. Separate coil springs of different stiffness could also be used around each cylinder.

As with any conventional shock absorber, the axial displacement of the pistons 13, 23 within the piston chambers 12, 22 will cause the axial ends 1a, 1b of the piston rod 1 to slide into and out of the piston chambers 12, 22, altering the volume of the piston chambers 12 , 22 available for the liquid they contain. This can be compensated in any of a number of conventional ways by allowing the pistons to move axially so that the incompressible fluid in the piston chamber 12, 22 does not prevent the piston rod 1 from sliding into it. The simplest way to provide this compensation is to provide an end of each piston chamber 12, 22. a small gas pocket, the gas compressing as the piston rod 1 retracts into the chamber and expands as it extends. This method is not, however, advantageous since there is a mixing of the liquid and gas in the piston chamber. In order to solve this problem, a small plastic bag filled with gas can be mounted in each piston chamber 12, 22.

A more preferred typical compensation method is shown in Figures 1a and 1b based on a typical "twin tube" type shock absorber. Each of the piston cylinders 11,21 surrounds an outer tube to form an annular compensation cavity 12a, 22a connected to the piston chamber 12,22. Each annular compensation cavity is largely gas-filled. Compression of the damper causes the piston rod 1 to slide into the piston chambers 12, 22 and displace the liquid into the annular compensation cavities 12a, 22a, compressing the gas therein in a known manner.

An alternative form of the first embodiment gas damper employing another conventional method of compensating for the insertion of the piston rod 1 into the piston chambers 12, 22 is shown in Fig. 3. At the distal ends 11a, 21a of the first and second cylinders are enclosed gas chambers 16, 26. In order to regulate the gas pressure inside the gas chambers 16, 25, valves 17, 27 can be mounted in a known manner. The gas chambers 16, 26 are separated from the respective piston chambers 12, 22 by axially displaceable dividing pistons 18, 28 which float freely and allow the transmission of pressure in the liquid gas chamber inside the piston chambers 12, 22. Instead of equipping the two cylinders with separate gas chambers 16, 26, it is contemplated that only one of the cylinders could have a separate gas chamber 16, 26. Moreover, it is contemplated that the gas supply for the gas chambers could be stored outside the cylinders and could communicate with the gas chambers 16, 26 by a hose or the like.

The equipment with gas chambers provides the possibility to further adjust the damping characteristics of each piston and the overall characteristics of the damper.

One skilled in the art will appreciate that each of the shock absorbers described herein will be provided with any of the standard configurations to allow for axial displacement of the pistons by compensating for the insertion and extension of the piston rod (s) into and out of the piston (piston) chamber (s).

A further modification of the first embodiment of the shock absorber is shown in Fig. 4. Here there is a sleeve 31 which extends between the first and second cylinders 11, 21. The axial ends 31a, 31b of the sleeves 31 are sealed against the first and second cylinders 11, 21, to form a closed sleeve cavity 32 between them. The ends of the sleeves are usually sealed against the outer wall of the cylinders by means of annular seals 33, which

They allow the sleeves to be axially displaced along the outer walls of the cylinders, allowing the first and second cylinders 11,21 to be displaced axially relative to each other as the shock absorber is compressed and stretched. It is also contemplated that the sleeve may be attached to one of the cylinders and may move axially with respect to the other while still allowing the shock absorber to stretch and compress. Each cylinder has a catch 34 to maintain a seal between the cylinders and sleeve 31 to prevent it from slipping off either cylinder end.

The use of the sleeve 31 improves the lateral stiffness of the damper and provides a further possibility to adjust the damping characteristics of the damper. Increasing the pressure inside the sleeve cavity 32 will increase the length of the shock absorber so as to raise the vehicle if necessary. The increased pressure will also make the damper harder to compress and easier to stretch. Reducing the pressure inside the cavity will reduce the length of the damper, lowering the vehicle, making the damper easier to compress and harder to stretch.

Figures 5 and 6 show a second embodiment of a shock absorber in a stretched and compressed state, respectively. The shock absorber consists of one cylinder 111 with a fluid-filled piston chamber 112. In the closed piston chamber 112, the first and second axially displaceable first and second pistons 113, 123, are positioned adjacent the respective ends 111a, 111b of the first and second cylinders. As with the first embodiment, any of a variety of valve mechanisms 114, 124 or other known means may be mounted to damp the axial displacement of each of the first and second pistons 113, 123 by fluid in the piston chamber 112.

A first piston 113 is connected to a first piston rod 101 extending through a first cylinder end 111a, while an equivalent second piston rod 201 is connected to a second piston 123 through a second cylinder end 111b.

The first piston rod 101 has a means for attachment to a mounting point in the vehicle body in the form of a threaded end 101a, while the second piston rod 201 is provided with a means for attachment to a vehicle wheel suspension in the form of a bearing 202. As in the first embodiment, as needed other forms of attachment can be used.

Mounted on each end of the cylinder 111, as in the first embodiment , is an end portion and a guide with a seal 119, 219. Figure 7 shows a gas damper modifying the second embodiment of the invention. The piston chamber is divided into piston chambers 112a, 112b, first and second closed gas chambers 116. The gas chamber 116 is separated from the first and second piston chambers 112a, 112b by axially displaceable dividing pistons 118, 128, much like the first embodiment. A valve 117 will typically be mounted in the gas chamber 116 to regulate the gas pressure, thereby further adjusting the damping characteristics of the damper.

As in the first embodiment, both versions of the second embodiment of the invention increase the available damping for a given shock absorber and halve the stroke of each piston and rod, with the resulting advantages discussed earlier. Increased controllability and customization of the damper damping characteristics are also provided by the piston valve mechanisms and the gas chamber (modified form in Fig. 7).

An alternative to the shock absorber of Fig. 3 is shown in Fig. 8. Instead of the closed gas chambers 16, 26 inside the first and second cylinders 11, 21, and outside the first and second cylinders 11, 21, gas chambers 16 ', 26 can be installed. '. Each closed gas chamber 16 ', 26' is placed in a separate gas cylinder 40, 50 which houses the dividing piston 18, 28. The piston chambers 12, 22 are connected to the respective gas cylinders 40, 50 by conduits 41, 51 at the distal end of the cylinders 11, 21. This configuration, using the outer gas cylinders 40, 50, allows the overall length of the shock absorber to be shorter than that of a shock absorber with Fig. 3.

An alternative solution similar to the damper shown in Fig. 7 is shown in Fig. 9. The piston chamber is divided into two first and second piston chambers 112a, 112b by a fixed baffle 145 attached to the cylinder wall 111. Piston chambers 112a, 112b, first and the second, are connected to opposite ends of the gas cylinder 140 by first and second conduits 141,151 adjacent to the fixed partition 145. A gas chamber 116 is formed between the axially displaceable dividing pistons 118, 128 in the gas cylinder 140.

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It is also contemplated that the fixed baffle could be mounted in the damper without any gas chamber (such as the damper in Figures 5 and 6). The fixed partition will divide the piston chamber into separate first and second sub-chambers. This will cause the shock absorber to actually function as two separate shock absorbers connected end-to-end, with no interaction between them. This configuration, allowing for separate adjustment of the two ends, however, will not be as smooth as the damper which leaves the piston chamber as a single chamber (Figures 5 and 6) or a damper in which the gas chamber separates the piston chambers (Figures 7 and 9).

While the various shock absorbers of the invention can only be connected to one coil spring as in a conventional shock absorber - with the upper end of the spring attached to the vehicle chassis and the lower end of the spring attached to the vehicle suspension - each shock absorber may be equipped with two coil springs, one being associated with the vehicle's chassis. with each end of the shock absorber.

The damper of Fig. 1 is shown in Fig. 10 with two coil springs 60, 61, a first and a second. A first helical spring 60 is associated with the first cylinder 11 and has a first end 60a attached and axially located with respect to the piston rod 1. A second end 60b of the first helical spring is attached and axially located with respect to the first cylinder 11. The second end 60b of the coil spring may either be axially attached to the first cylinder 11, perhaps by a plate attached to the first cylinder and bearing frontally against the spring end 60b, or may be axially attached to the chassis / body of the vehicle about the point where it is attached. threaded spindle 15. A second coil spring 61 is associated with the second cylinder 21 and has its first and second ends 61a, 61b, attached and axially fixed in a similar manner. The second coil spring second end 61b will typically be attached to the vehicle suspension. The first ends 60a, 61a are preferably attached and axially positioned with respect to the piston rod 1 by means of an annular thrust plate 62 attached to the piston rod 1 between the first and second cylinders 11, 12. The first ends 60a, 61a abut this annular plate so as to fix their axial position with respect to the piston rod 1. The use of two coil springs in this way makes it possible to use springs of different stiffness associated with each of the cylinders 11, 12. A first coil spring 60 with a given stiffness can thus be connected to a first cylinder 11 with a specific damping characteristic, and a second coil spring 61 with a different stiffness. given stiffness may be combined with a second cylinder 12 with different damping characteristics.

The damper of Fig. 4 could be modified in a similar fashion with two first and second helical springs 60, 61, with a stop plate 62 axially securing the first ends 60a, 61a of the helical springs which is attached to the sleeve 31, not to the piston rod 1.

The damper of Fig. 5 is shown in Fig. 11 with two coil springs 60, 61, a first and a second. The first helical spring 60 is associated with the first piston rod 101 and has a first end 60a attached and axially secured with respect to cylinder 111. A second end 60b of the first helical spring is attached and axially located with respect to the first piston rod 101. The second end 60b of the first helical spring may or be axially secured. to the first piston rod 101, e.g. by a plate attached to the first piston rod and bearing frontally against the second end 60b of the spring, or it may be axially attached to the vehicle body about the point where the threaded end 101a is secured. A second helical spring 61 is associated with the second piston rod 201 and has its first and second ends 61a, 61b attached and axially fixed in a similar manner. The first ends 60a, 61a of the coil springs are preferably attached and axially fixed to the cylinder 111 by an annular thrust plate 162 attached thereto. Thus, a two coil spring arrangement may be used for the shock absorbers of Figures 7 and 9.

The single-cylinder shock absorbers with two pistons of Figs. 5 to 7 and 9 and 11 may be provided with a sleeve or sleeves in a similar way to the two-cylinder shock absorbers with one piston rod of Fig. 7. The shock absorber modified in this way is shown in Figs. 12 and 13, respectively in the condition. tight and stretched.

The first sleeve 131 extends telescopically around the cylinder 111 and is sealed against it and extends from the first cylinder end 111a. The distal end 131b of the first sleeve 131 is closed by an end wall such that the first sleeve 131 defines a closed first sleeve cavity 132. The first piston rod 101 is attached to the first sleeve such that the axial displacement of the first piston rod 101 will ensure an even displacement of the first sleeve 131 and a corresponding change in volume and pressure in the first sleeve cavity 132. A valve 138 will be mounted in the first sleeve so as to allow the gas pressure in the first sleeve to be adjusted. her. The second sleeve 231 may be

Similarly mounted on the other cylinder end 111b. Extending the damper to the state of FIG. 13 will increase the volume and consequently reduce the pressure in the first and second sleeve cavities 132, 232.

Increasing the gas pressure in the first sleeve cavity 132 through the valve 138 will increase the length of the shock absorber and make it more difficult to compress and easier to stretch. The gas pressure in the second sleeve cavity 232 may also be adjusted to further adjust the characteristics of the damper, if desired.

Here, the first sleeve 131 cooperates with the cylinder 111 such that the first annular recess 135 is formed in the area of ​​the overlap between the first sleeve 131 and the cylinder 111. One axial end of the first closed annular recess 135 is formed by a first annular seal 133 which is attached to it. cylinder at its first end 111a and sealingly engaging the first sleeve. The opposite axial end of the first closed annular recess 135 is formed by a second annular seal 134 which is attached to the first sleeve 131 near its proximal end 131a and seals with the cylinder.

111. The first annular cavity will typically have a valve 136 for regulating the gas pressure therein. The second closed annular recess 235 in the second sleeve 231 can be made in a similar manner.

The design of the closed annular recesses 135, 235 provides the possibility of further adjustments to the compression and tension (or rebound) strokes. Increasing the pressure in the first sleeve cavity 132 compared to the first annular cavity 135 will increase the length of the shock absorber and increase the force required to compress the shock absorber while reducing the force required to extend the shock absorber. The same effect is achieved by reducing the pressure in the first annular cavity 135. Increasing the pressure in the first annular cavity 135 or reducing the pressure in the first sleeve cavity 132 will shorten the shock absorber. If desired, the pressure may be regulated in various ways in the second sleeve cavity 232 and the second annular cavity 235. Additional adjustment possibilities will be obtained if two coil springs of different stiffness are used in the shock absorber.

The piston chamber will preferably be separated into two piston chambers, first and second, by a fixed partition 145, and a gas cylinder 140 (as shown in Figure 12) may be used to soften the response of the damper, as in the damper of Fig. 9.

The use of a sleeve 131 as described above and illustrated in Figures 12 and 13 may also be the case with a conventional single cylinder and single piston damper as illustrated in Figures 14 and 15 in a stretched and compressed state, respectively. Bushing 131 is mounted on cylinder 311 in the same manner as any of the shock absorber bushings of FIG. 12, with a single piston rod 301 attached to bushing 131. The sleeve 131 may cooperate with the cylinder 311 to form a closed annular recess 135, allowing the pressure to be adjusted in both the sleeve recess 132 and the annular recess 135; or the sleeve 131 may be mounted to form only a closed sleeve recess 132.

The formation of annular recesses can also be achieved in a similar manner with the shock absorber shown in FIG. 4 with two cylinders and one piston rod and a sleeve. Such a modified damper is shown in Figures 16 and 17 in a compressed and extended state, respectively. The first annular recess 35 is formed in the area of ​​the overlap between the first cylinder 11 and the sleeve 31. One axial end of the first annular recess 35 is formed by a first annular seal 33 which is attached to the first cylinder at its proximal end 11b and seals against the sleeve 31. The opposite axial end of the first annular recess 35 is formed by a second annular seal 37 which is attached to the sleeve at its first end 31a and sealingly engaging the first cylinder 11. The first closed annular cavity is usually provided with a valve 36 for regulating the gas pressure therein. A second closed annular recess 35 'can be formed on the second cylinder 21 in the same manner.

Again, the use of a different pressure in the sleeve cavity 32 compared to the first and / or second annular cavities 35, 35 'enables the stroke, compression and extension characteristics to be adjusted. Increasing the pressure in the sleeve cavity 32 will extend the shock absorber and may be used to level the vehicle when heavily loaded. Increasing the pressure in the sleeve cavity 32 will also increase the force required to compress the shock absorber, thereby producing a harder compression stroke. Alternatively, pressurizing the annular cavities

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35,35 'will shorten the damper and increase the force necessary to extend it, giving a harder stretch (or rebound) stroke.

Dampers providing closed sleeve cavities and closed annular cavities, as shown in Figures 12 to 17, may be connected to compensate for the overall suspension of the vehicle. Fig. 18 shows two shock absorbers according to Fig. 12 connected in this way. The closed first sleeve cavities 132 of each shock absorber are filled with liquid (typically oil), not gas as is the case with the annular cavities of the individual shock absorbers. Thus, there is no need to install gas pressure regulating valves in the annular cavities. The closed first annular cavity 135 of each shock absorber is operatively associated with the first sleeve cavity 132 of the second shock absorber such that increasing the closed volume of the first annular cavity 135 reduces the gas pressure in the first sleeve cavity 132 of the second shock absorber. Conversely, reducing the volume of the first closed annular cavity 135 of one shock absorber will increase the gas pressure in the first sleeve cavity 132 of the second shock absorber.

To establish the above operative connection, a first closed annular recess 135 of one shock absorber is connected via a line 171 to the first end 172a of the control cylinder 172, and the first sleeve recess 132 of the second shock absorber is connected via a line 175 to a second end 172b of the control cylinder 172. Inside the control cylinder 172 is a dividing piston 173 and a control cylinder that isolates the associated first closed annular recess 135 and first sleeve recess 132. Dividing piston 173 the control cylinder is equipped with a piston rod 174 which is housed in the tubular portion 172c of the control cylinder 172. with a reduced cross section facing the first end 172a of the control cylinder. The piston rod 174 and the tubular portion 172c are dimensioned such that the piston rod 174 encloses the tubular portion 172c, and the extended first end 172a of the piston rod 174 consequently isolates the first closed annular cavity 135 from the main chamber of the control cylinder housing the dividing piston 173 for the control cylinder.

The operation of this assembly will now be elucidated with respect to a motor vehicle in a curve when the left side shock absorber is compressed and the right side shock absorber extends as shown in Fig. 18. The stretching of the right shock absorber will reduce the volume of its first annular recess 135, causing the fluid in the first annular recess 135 to be forced through conduit 171 where it will apply pressure to a relatively small area of ​​the protruding end 174a of the associated piston rod 174. This pressure will act to push the piston rod 174 against the gas resistance on the opposite side of the dividing piston 173 for the control cylinder and build up gas pressure in the main chamber of the control cylinder 172 which is connected to the first sleeve cavity 132 of the left hand side damper. This pressure build-up in the first sleeve cavity will in turn act to extend the left hand shock absorber to help return it to its original position. Likewise, compressing the left shock absorber will draw fluid into its expanding first annular cavity 135, dragging the associated piston rod 174 with it and reducing gas pressure in the main chamber of the control cylinder and in the first sleeve cavity 132 of the right shock. This reduction in pressure will act to compress the right shock absorber back to its original position. The interaction between the two shock absorbers on opposite sides of the vehicle will thus help to keep the vehicle level. The second sleeve cavity 232 and the second sleeve cavity 235 may also be interconnected in the same manner.

This assembly can be used to link the four shock absorbers of a motor vehicle in various ways. The front left and right shock absorbers may be linked, with the left and right rear shock absorbers being linked independently. Alternatively, the left front shock could be linked to the right rear shock and the right front shock to the left rear. Making the connections at the first and second ends of the shock absorbers will allow for a more complex connection network.

The magnitude of the equalizing effect of the connections between the shock absorbers can be varied by changing the relative area between the outer end of the piston rod and the area of ​​the main piston which is affected by the gas.

Each of the shock absorbers in Figures 14 to 17 may also be operatively connected in the manner described above, connecting the various sleeve cavities to the liquid filled annular cavity (s) of the other shock absorber.

Figure 19 shows the assembly of Figure 18 with the left and right piston chambers 112 of the left and right shock absorbers connected via a gas cylinder 180. The piston chambers 112 are connected.

With opposite ends of gas cylinder 180 through conduits 181. A gas chamber 182 is formed between two dividing pistons 183 housed in the gas cylinder 180. Gas cylinder 180 operates to compensate for the extension of the piston rods into the piston chambers 112 of each shock absorber and soften the action of the damper as discussed above.

Figure 20 shows an assembly similar to that of Figure 19 using two twin cylinder shock absorbers with one piston rod and sleeve, as in Figures 16 and 17. Gas cylinders 180 connect respective piston chambers 12, 22 in the left and right shock absorbers as shown in Figs. discussed above. The sleeve recess 32 of each shock absorber is associated with one or both of the first and second closed annular recesses 35, 35 'of the second shock through a control cylinder 172 as discussed above with respect to the assembly of Figure 18. liquid rather than gas. An annular recess 35 or 35 'is connected to the first end 172a of the control cylinder 172 via a conduit 171, while the sleeve recess 32 is connected to the second end 172b of the control cylinder 172 via a conduit 175. The control cylinders 172 are provided with the same piston arrangement. separating 173, control cylinder and piston rod 174 as described above.

The operation of this assembly is generally the same as that of Fig. 18. The extension of the right shock absorber as it turns will force fluid out of the annular cavity 35 'into the control cylinder 172 and thereby increase pressure in the sleeve cavity 32 of the left shock absorber to extend the compressed left shock absorber. Similarly, the twisting compression of the left shock will draw fluid into its annular cavity 35 'from the associated control cylinder 172 and thereby reduce pressure in the sleeve cavity 32 of the right shock to compress the extended right shock.

As discussed above, when compressing and stretching any shock absorber, the axial displacement of the piston (s) within the piston chamber (s) will cause the piston rod (s) to slide into and out of the piston chamber (s). (s) by changing the volume of the piston chamber (s) available for the fluid. The shock absorbers shown in Fig. 21 to 26 provide other alternative means of compensating for these variations in the volume of the piston chamber (s) using several of the shock absorber assemblies described.

Figures 21 and 22 show a damper similar to that of Figures 14 and 15 but using alternative compensation means. In this embodiment, instead of sealing and creating pressure in the annular cavity 135 formed in the area of ​​the overlap between the sleeve 131 and the cylinder 311, the annular cavity 135 is connected to the piston chamber 312 via openings 191 located near the first cylinder end 311a. Both the piston chamber 312 and the annular cavity 135 are filled with oil. The cross-sectional area of ​​the annular recess 135, measured in a plane not perpendicular to the longitudinal axis of the piston rod 301, is substantially equal to the cross-sectional area of ​​the piston rod 301. In this configuration, as the shock absorber is compressed and the piston rod 301 retracts into the piston chamber 312, the volume reduction of the piston chamber 312 is substantially identical to the increase in the volume of the annular cavity 135 so that the oil displaced by the piston rod 301 from the piston chamber 312 is absorbed by the increased cavity volume. ring 135.

This configuration could also be applied to the two piston rod configuration of Figures 12 and 13, both annular recesses 135, 235 being connected to respective piston chambers.

Utilizing the volume change of the annular cavity to receive the oil displaced by the piston rod avoids the need for a separate compressible gas chamber separated from the piston chamber by a separating piston as described above. The absence of a pressurized gas chamber also avoids the pressurization of hydraulic fluid or oil filling the piston chamber. Cavitation and aeration are also effectively eliminated.

The damper configuration of Figures 16 and 17 can be similarly modified to accommodate the oil displaced by the piston rod. Such a modified damper is shown in Figures 23 and 24. Again, the first and second annular recesses 35, 35 'are connected by first and second piston chambers 12, 22, through holes 191 near the proximal ends 11b, 21b of the cylinder, respectively. the first and the second. Here again, the cross-sectional area of ​​the annular recesses 35, 35 'is substantially equal to the cross-sectional area of ​​the piston rod 1.

Various embodiments of the invention may be applied to McPherson strut type shock absorbers, with particular examples being shown in Figures 25 and 26. The embodiment shown in Fig. 25 is identical to Fig. 22, with the distal end 21a of the second cylinder attached to the shin. 401 McPherson strut and inside it there is a longitudinally displaceable bushing 31.

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Another possible variation is shown in Fig. 26, which is identical to the shock absorber of Fig. 25 except that the first cylinder 11 and annular recess 35 are configured as in the embodiment of Figs. 16 and 17, without an opening connecting annular recess 35 and first piston chamber. Accordingly, to ensure the movement of the piston rod 1 into the first piston chamber 12, the separating piston 18 is mounted in the first cylinder 11, separating the first piston chamber 12 from the gas chamber 16 in the usual manner.

Various other variations and combinations of the properties of the described shock absorbers will be apparent to one skilled in the art.