Untitled record

PATENT

FRENCH REPUBLIC

MINISTRY

INDUSTRY AND TRADE

INDUSTRIAL PROPERTY SERVICE

Gr. 5. - Cl. 3.

N ° 1.069.128

Improvements to suspension shock absorbers.

Mr. Paul FAUQUET residing in France (Seine).

Requested on Novem ber 22, 1952, at ll^h 40^m, in Paris.

/ OA

AT

Issued February 10, 1954. - Published July 5, 1954.

(BrereZ of invention whose delivery was postponed in execution of article 11, § 7, of the law of July 5, 1844 modified by the law of April 7, 1902.)

The present invention aims to improve, in general, suspension shock absorbers as well as damped suspensions of the hydraulic or pneumatic type. These devices can be used on all types of land vehicles or on aircraft landing gear.

A well-known embodiment, among others of such a general type of apparatus will be very briefly described as follows:

A piston, actuated by a control fixed either on the suspended part, or on the unsprung part of a vehicle, moves in a cylinder itself fixed on the then opposite part of said vehicle. A braking device located in the piston differentially controls the alternating flow of a liquid contained in the cylinder. A compensating tank, partially filled with the same liquid, communicates with the cylinder in a studied manner.

It goes without saying that this particular description of a telescopic hydraulic device, with alternating braking and differential effect, is given by way of example and is therefore in no way limiting.

This patent will particularly aim to protect and improve the following devices, the use of which may judiciously be provided, in isolation or in certain combinations on any suspension damper or damped suspension of the hydraulic or pneumatic type, with direct action or not.

1 ° A braking device produced by combinations of successive fluid controls. The flow section of a partial control can be constant or elastically variable. The advantages among others, of such a device produced according to the invention are the following:

at. Increased fluid control surfaces, improving flexibility and braking efficiency;

b. Limitation or even elimination of the emulsion generally generated by ener braking4 - 41088

Booklet price: 100 francs.

liquid and this, thanks to a progressive relaxation of the braked liquid.

2 ° An automatic fluid flow control device, intended to regulate certain determined displacements of the piston. Among other things, this device can:

at. Very vigorous braking of certain rebounds above the equilibrium point, even avoiding, at the end of the race, any contact with rigid elements;

b. A differential flow control, according to the position of the piston in the cylinder, in other words according to the vehicle load or the amplitude of the oscillations.

3 ° A reserve chamber, partial or not, disposed at one end of the piston and movable jointly with the latter. (Improvement concerning only certain devices of the hydraulic type). Such an arrangement of the organs can provide, among other things, the following advantages:

at. Realization of a single tube telescopic hydraulic device, which automatically leads to a simplified machining of this device and ensures it, for a given section, a maximum volume of fluid controllable during its operation;

b. Very significant increase in fluid control surfaces.

Fig. 1 is a vertical section of a damper piston according to the invention. We note in particular:

The annular valve 6 with central guide, valve resiliently recalled by the ring 5 of plastic material and controlling the annular passage 11. The fallen edges of this valve limit the stroke thereof; conversely, an enveloping annular stop could have been provided here, the fallen edges of which would limit the travel of a flat annular valve.

The annular valve 8, resiliently returned by a helical spring bearing against the stop 10. This valve controls the channels 7.

The narrow annular passage 9, reserved between the side - 2 - [1.069.128] side of the stop 10 and the cylinder wall. The said stop is here hollowed out to allow the spring to be accommodated and to produce a large lateral control face in the passage 9.

The stop of the ring 5, stop here tripling the passage of the fluid, namely: by the channels 4, the annular groove 3 and the channels 2. It is possible to provide for the channels 2 a larger flow section than for the channels 4, this in order to achieve a progressively reduced access to the elastic braking of the second stage and a progressively relaxed escape of the elastically braked fluid at the first stage.

Finally, note the particular arrangement of the constituent elements of the piston.

Fig. 2 is a vertical section of a damper piston according to the invention. Note, more particularly:

Braking with a constant flow section, braking due to the combined action of successive partial controls and to which a differential effect is here given by the central channels 15, automatically opened during the first time of the device and closed during the second time.

The attachment to the control 1, in a braced manner, of the elements of the partial controls. In the present embodiment, said elements are arranged partly on the inside of the hollow body of the piston and partly on each end of said piston body.

One can provide a central constriction of the flow, in other words, a very reduced section but however sufficient for the annular passage 48. On either side of this reduced passage, the flow sections of the partial controls can then gradually increase towards outside. Thus for example we would have: the flow section of the channels 13 larger than the flow section of the annular passage 48, but smaller on the other hand than the flow section of the annular passage

12.

Fig. 3 is a vertical section of a telescopic hydraulic shock absorber. We note in particular:

The reserve chamber 26 fixed at the end of the control 1 by an element also common to the body of the piston. The closure member 25 which serves as a stop for the return spring 51 of the elastic braking. The annular passage 27 reserved between the lateral face of the reserve 26 and the wall of the cylinder. The base 34 externally of concave shape, so as inter alia to collect the emulsion and the air contained in the lower chamber of the cylinder and thus to facilitate their access to the reserve. In the bottom of the base 34 are arranged the conventional members controlling, in a known manner, the entry of the fluid into the reserve and its exit. It will be noted however here, the addition to these members of a channel j 33, of very small section and with free flow j in both directions this, inter alia, in order to allow the passage of air in the reserve, during the appliance stops operating. The partition 29, here in flexible plastic material, elastically fixed on the element 49 of the control and which limits the disturbances of the fluid inside the reserve chamber 26. The float 28, here in plastic material with perfectly smooth surface and which controls by adhesion the displacements of the liquid on the surface.

The body of the piston, in which are elastically controlled, the channels 22 by the annular valve 21 and the channels 23 by the annular valve 24. A differential effect in the elastic braking is achieved here by using a return spring 51 of greater resistance than the return spring 50.

The annular passage 20, progressively widened at 19. The said passage is used here for a triple action, namely:

at. At first, as an exhaust control of the elastically braked liquid;

b. Secondly, as control of access of the liquid to elastic braking;

vs. In combination with the ring 18 arranged at the upper end of the cylinder, as a brake flow adjustment at the end of the piston stroke. In this setting, the ring 18 by gradually and completely closing the annular passage 19-20 here brakes very energetically at first, then stops the movement of the piston, and this only by compression of the fluid. A flexible annular seal, of studied height, could be provided around the control. This seal, by bearing at the end of the stroke, on the one hand against the face of the piston and on the other hand against the cylinder closing member would reinforce the action of the sealing device at the time of the internal over-compression produced by the closure of the flow orifices.

This kind of automatic flow adjustment can also very particularly be used on a damped suspension produced entirely hydraulically or pneumatically, as well as on a mixed damped suspension in which the spring to be checked is disposed inside the device.

The ring 36 disposed in the lower end of the cylinder. For a determined position of the piston in the cylinder, a position corresponding here to a large amplitude oscillation or else to a high load of the vehicle, said ring 36 partially blocks the annular passage 27 which then momentarily reinforces the general braking of the device. It goes without saying that the new annular passage, although reduced, remains sufficient to ensure the flow of the liquid in all circumstances. The ring 36 could be machined directly in the cylinder, in the present embodiment it consists of a strip of calibrated thickness, strip reported by electrical welding against the wall of the cylinder.

The chamber 39 and its reduced inlet 38. This chamber is designed to collect the metallic or organic particles suspended in the liquid. A special absorbent cartridge or, if necessary, a stuffing plug can be placed inside, to facilitate the fixing of residues. Such a device by purifying and clarifying the liquid, reduces the wear of the sliding elements and limits the disruptive effects of braking, caused by variations in viscosity of the braked liquid.

The realization of the piston body by assembling elements simplifies the repair of this member, during the overhaul of the device.

Fig. 4 is a vertical and partial section of a telescopic hydraulic device, of the same kind as the previous one. With such an arrangement of the organs, giving an exceptionally large control surface, a simple device has been provided, not using elastic braking. A differential effect is here given by automatic opening of the discharge channels 40 and 44 during the first time of the device. The channel 40 controlled by the valve 41 is used at the end of the piston stroke, to automatically discharge the flow setting 18-20 at first; this therefore allows a rapid change of direction during extreme displacements of said piston.

Provision may be made for the general flow of braking of the apparatus, the same improvements as those previously exposed during the description of braking in FIG. 2. Thus for example: a calibrated constriction of the flow at the second stage, could be provided by the central channels 45.

Fig. 5 is a vertical and partial section of a mobile reserve chamber, according to the invention.

In this embodiment, the reserve chamber 26 is extended in the hollow interior 47 of the control 1. Said control 1 may even include an additional container at its upper end.

The conventional members controlling the communication between the cylinder and the reserve are here arranged, eccentrically, on the concave base 34 of said reserve 26. Such an arrangement is particularly advantageous for a device operating in an inclined position. A reference preferably provided on the external member for fixing the control 1 may make it possible to judiciously orient the installation of the device in such a way, for example, that the orifice 32 for access to the reserve is then located at a level higher than the channel 31 returning to the cylinder.

[1.069.128]

This eccentric arrangement of the control members may also very particularly be provided on a monotube telescopic hydraulic device of the so-called inverted type and in which the reserve is located directly above the working cylinder.

It goes without saying that in all the braking devices according to the invention it will be possible, in the well-known manner, to use certain control elements with the expansion coefficient studied with a view to automatic correction of the flow section according to the temperature. fluid.

As for the operation of each of the devices presented, it explains itself and will therefore be described very succinctly.

Piston shown in fig. 1. Flow of braked fluid.

At first: annular passage 9, annular passage 11, elastically controlled by the valve 6, channels 4, annular junction passage 3, channels 2.

In the second stage: channels 2, annular junction passage 3, channels 4, channels 7 elastically controlled by the valve 8, annular passage 9.

Piston shown in fig. 2. Flow of braked fluid.

At first time]: annular passage 17, channels 16, annular passage 48, then automatically discharged through channels 15, channels 13, annular passage 12.

In the second step: reverse flow, with the only difference that the channels 15 then being closed by the valves 14, the fluid in this partial control, flows only through the annular passage 48.

Telescopic hydraulic shock absorber shown in fig. 3. At first; part of the liquid contained in the lower chamber of the cylinder passes into the upper chamber by the following controls: annular passage 27, passage 46, channels 22 elastically controlled by the annular valve 21, annular passage 20-19.

During this time, a volume of liquid equivalent to the volume of the part of the control 1 having entered the cylinder; passes from the lower chamber of said cylinder into the reserve 26 via the small free channel 33 as well as through the orifices 32 (the latter invisible in FIG.) then 30 of the calibrated control 49.

In the second step: part of the liquid contained in the upper chamber of the cylinder passes into the lower chamber by the following controls: annular passage 19-20, channels 23 elastically controlled by the annular valve 24, passage 46, annular passage 27.

During this time, a volume of liquid equivalent to the volume of the part of the control 1 having withdrawn from the cylinder, passes from the reserve 26 into the lower chamber of said cylinder via the - lt - [1.069.128] small free channel 33 as well as through the channels 31 controlled by the foil 35.

The devices shown in fig. 4 and fig. 5 are only close variants of the previous device. Their particular characteristics already described, do not modify the principle of operation.

The devices exposed and described have been given solely by way of examples, in order to show the possibilities of the invention. It goes without saying that we can add to them any modifications and variants which do not depart from the spirit of the invention.