Wheel suspension

Wheel suspension

Technical field

The present invention relates to a vehicle according to the introduction of patent claim 1.

The invention can be applied to the vehicle manufacturing industry.

Prior art

There are currently wheel suspensions in which the wheels are mounted on a connection element and the connection element is mounted in turn around a rotation point in the vehicle frame. A wheel suspension of this type is described in Swedish patent application No. SE 0102878-6, in which the wheel suspension is designed to be able to absorb vertical movements that are transmitted to the wheels when they are driven with jerks, so that a compensation action is achieved for the vehicle.

WO 02/062285 describes a wheel suspension comprising a connection element to which a force can be transmitted to improve the ascent characteristics of a vehicle. The connecting element comprises a lifting wheel, which lifts the front end of the vehicle by means of a force transmitted to a lever arm construction. The connecting element is a complementary construction and is separated from the main wheels of the vehicle. Construction means that a user must perform an additional maneuver to make the vehicle ascend. There are currently wheel suspensions in which the wheels are mounted on a connection element and the connection element is mounted in turn around a rotation point in the vehicle frame. In DE 100 19 467 A1 a vehicle according to the preamble of claim 1 is described, comprising a tandem load bearing roller unit, with two rollers rotatably mounted on a support that can pivot around a point located below a plane in which the rotation axes of the rollers are located.

US 4 056 158 discloses an articulated wheel suspension to the vehicle frame to absorb irregularities of the terrain. The vehicle is hydraulically driven and can be oriented in sliding by rotating on a transverse pair of wheels, allowing all other wheels to slide laterally to each new position.

The present invention aims to find a solution that involves the improvement of the climbing characteristics of an obstacle, such as a curb, while, at the same time, the simplest possible handling of the vehicle is guaranteed. At the same time, the present invention aims to produce a simple structure that effectively provides an inherent jump function without complementary spring elements.

This has been achieved by means of the present invention thanks to the vehicle described in claim 1, the wheel suspension being characterized by the distinctive features specified in the characterizing part of the patent claim 1.

In this way the necessary driving force is used to also lift the wheels of the first wheel axle. This is achieved through a lever arm effect, in which the rotation of the connecting element is effected by means of the force applied to the point of rotation, that is to say a linear propulsion force of the vehicle in the direction of propulsion, and the distance achieved for the lever arm of the connecting element.

A rotation point that has been lowered below the center of the wheel axles that creates said lever arm effect also contributes to a smoother propulsion of the vehicle, since the driving force becomes to some extent a force of lifting. Therefore, there is also no need to use any elastic element that opposes the rotation of the connecting element.

Alternatively, a first distance between the first wheel axle and the rotation point coincides with a second distance between the second wheel axle and the rotation point.

Therefore, a user can place the wheel suspension wheels in line with the direction of travel regardless of the order in which the front and rear wheels are adjusted, while at the same time the effect of desired lever arm. The pivoting capacity of the vehicle remains equally good.

Preferably, a first distance between the first wheel axle and the rotation point differs from a second distance between the second wheel axle and the rotation point.

In this way the lever arm effect can be achieved even in a steep ascent, maintaining the distance generated by the moment, if the second distance between the second wheel shaft and the point of rotation is shorter than the first distance between the first wheel tree and rotation point.

Conveniently, the first and second wheel axles are arranged in the connecting element such that the extensions of the wheel axes are parallel to each other and the second wheel axle is arranged behind the first wheel axle seen in the direction of displacement.

Alternatively, the second wheel axle is also offset with respect to the first wheel axle seen in the direction of travel, so that wheels mounted on the axles are located on each side of the rotation point.

Conveniently, the wheels are also arranged so that they overlap each other. This optimizes the pivot capacity.

Preferably, the surface of the respective wheel has a lateral peripheral surface for contact against the road, the wheels being mounted on the wheel axles such that the peripheral surfaces face each other.

This reduces the tendency of the wheel assembly to twist when it comes into contact with an obstacle.

Conveniently, the frame is equipped with a stop element arranged to engage with the connection element to prevent the connection element from turning over, so that the first wheel axle does not adopt the position of the second wheel axle.

In this way a user can lift the vehicle frame without having to rotate the connecting element to its original position before lowering it.

Alternatively, the vehicle is a walker.

Preferably two wheels are arranged in the respective first and second wheel axles.

Conveniently, the wheel suspension is arranged so that it cannot pivot in the vehicle, but so that it allows the connecting element to rotate around the rotation point.

Brief description of the drawings

The present invention will be explained in more detail below with reference to the accompanying drawings, in which, in a schematic representation:

Figure 1 shows a wheel suspension according to a first embodiment;

Figures 2a-2b show a wheel suspension according to a second embodiment;

Figures 3a-3b show a wheel suspension according to a third embodiment;

Figure 3c shows a wheel suspension from above;

Figure 4 shows the wheel suspension of Figures 3a-3b with preferred dimensional relationships;

Figures 5a-5b show a basic ascent diagram;

Figure 6 shows a fourth embodiment;

Figure 7 shows a fifth embodiment;

Figures 8a-8d show a sixth embodiment;

Figures 9a-9b show a further embodiment; and

Figures 10a-10b show a further embodiment.

Way (s) of carrying out the invention

The present invention will now be described as illustrative embodiments. For reasons of clarity, the components not important for the invention have been omitted from the drawing. The same parts shown in

Figure 1 shows a wheel suspension 1 according to a first embodiment. The wheel suspension 1 is mounted on a frame 3 comprising a fork 5 of a vehicle (not shown). In its sense of propulsion, the vehicle is arranged to be able to climb obstacles 7, such as a curb. The wheel suspension 1 comprises a connecting element 9, which is rotatably arranged on the fork 5 around a rotation point R. For the propulsion of the vehicle, a force Gx is applied to the frame 3 and, therefore, through the fork 5, also to the rotation point R. The connecting element 9 in the form of a rectangular plate comprises a first (front) and a second (rear) wheel shaft 11, 13 mounted on the front and rear part 15, 17 respectively of the connecting element 9.

A front wheel 19 and a rear wheel 21 are arranged in line one behind the other and are rotatably arranged in the respective wheel shaft 11, 13. The rear wheel shaft 13 serves as the moment axis X around which the connecting element 9 tends to rotate when a force Fx is applied, through the front wheel 19, to the front wheel shaft 11 in a direction substantially opposite to the direction of travel This force Fx and force Fy are components that constitute force F. The force F that is generated when a curb is raised contributes to a moment of rotation M on the rear wheel axle 13 that lifts the front wheel 19.

The connecting element 9 is arranged to act as a lever arm thanks to the fact that the rotation point R is located at a distance b from an imaginary straight line L that intersects the first and second wheel shaft 11, 13 and in a plane transversely to the extension of the moment axis X. To create the lever arm b, the rotation point R has therefore been placed below the imaginary straight line L. The driving force Gx and the lever arm b create a moment on the rear wheel axle 13, which raises the connecting element 9. This moment is complemented by an additional moment created by the force F acting on the front wheel 19 and the distance a. In the theoretical case where the front wheel 19 of the wheel suspension 1 collides with an obstacle 7 at least height equal to the height of the wheel axles 11, 13 (or the radius of the wheel 19) above the surface of the ground U, the distance a will be equal to zero. Simply the lifting moment (the pair of forces M) created by the force Gx and the distance b will therefore cause the wheel suspension 1 to rotate around the second wheel shaft 13.

In Figure 1, the two wheel shafts 11, 13 are symmetrically positioned around the rotation point R and, since the wheels 19, 21 are arranged in line one behind the other, the pivoting capacity of the vehicle is not affected. when an obstacle is saved. According to this embodiment, a first distance d between the first wheel axle 11 and the rotation point R coincides with a second distance c between the second wheel axle 13 and the rotation point R.

Figure 2a -2b shows, in a side view and in a front view, a wheel suspension 1 according to a second embodiment. The first and second wheel axles 11, 13 are arranged parallel to each other in the connecting element 9. The first wheel axle 11 comprises a front wheel 19. The second wheel axle 13 is divided into two subtrees, each supporting a rear wheel 21. The rear wheels 21 are arranged behind the front wheel 19 seen in the direction of travel. The second wheel axle 13 (the two subtrees) is / are offset with respect to the first wheel axle 11 seen in the direction of travel, so that the wheels 19, 21 mounted on the axles 11, 13 are located partially side by side and on each side of an imaginary line that intersects the rotation point R and runs longitudinally parallel to the direction of travel. Alternatively, two front wheels can be mounted on the first wheel axle 11.

Figures 3a-3b show a wheel suspension 1 according to a third embodiment. A front wheel 19 and a rear wheel 21 are arranged in a connecting element 9. The wheels 19, 21 are partially located next to each other and are mutually displaced in the direction of travel. Figure 3a shows the wheel suspension 1 from above. The rotation point R of the wheel suspension 1 is constituted by a rotation axis arranged in a fork 5 (not shown) of a manual vehicle (for example a walker, a baby carriage). The fork 5 is arranged so that it can pivot in the frame 3 of the walker around a pivot axis S. The connecting element 9 is V-shaped and supports the front and rear wheels 19, 21 at the respective connecting end, such as illustrated in figure 3b.

Figure 3c shows a wheel suspension from above. The pivot axis is in this case a spherical joint 20, which simultaneously constitutes a rotation point R and a pivot axis S (instead of making the rotation point a horizontal axis in the direction transversely to the separate direction of travel of the pivot axis) and the two wheel shafts are placed symmetrically on each side of the rotation point R. The symmetrical placement of the wheels 19, 21 allows an optimum pivoting capacity of the vehicle. At the same time, the wheels are positioned so that they overlap each other and are sufficiently separated so that the pivoting capacity can be optimized without affecting the structure of the wheel suspension 1.

Figure 4 schematically shows the wheel suspension 1 in Figures 3a-3b according to one embodiment. To create the lifting lever effect to improve the climbing characteristics, the rotation point R of the connecting element 9 (the connecting arm) is placed at a distance b below the imaginary straight line L intersecting the first and the second wheel shaft 11, 13 and in a plane transversely to the extension of the moment axis X.

The relationship between the front distance d between the front wheel shaft 11 and the rotation point R and the rear distance c between the rotation point R and the rear wheel shaft 13 is such that the front distance d is greater than the distance rear c.

A simplified equation to calculate the rotation around X can be defined as:

where F is the force absorbed by the wheel suspension 1 when driving against an obstacle 7. F is divided into the components Fy (lifting force) and Fx (a force acting against the vehicle in the direction of travel).

Gx is the force that acts on the vehicle in the direction of travel. Gy is the force that is applied to the vehicle in the direction of the ground surface U. In the case of a walker, the body weight of a user (not shown) will act around the rotation point R with a force G (not shown) for the propulsion of the walker. This force G is divided into the components Gy and Gx, where Gx is defined as the driving force.

Distance b is the lever arm created to improve the ascent characteristics of the walker. The distance b is greater than 0 and less than the radius r of the rear wheel 21. The distance b is between 2 and 90%, preferably between 25 and 70%, of the radius r.

The angle a is determined by the relationship between the height of the obstacle and the radius r of the wheel, that is, if the radius of the wheel is equal to the height of the obstacle, the angle a is equal to 0.

where Fy constitutes a lifting force for the wheel suspension 1.

Since the distance c is less than the distance d, the weight of the user will be distributed mostly to the rear wheel 21, which further improves the ascent characteristics of the wheel suspension 1, since the front wheel, due to at the lowest load, it tends to rise more easily from the ground surface.

Since the rotation point has been lowered below the line L, the wheel suspension 1, when ascending up an obstacle when the connecting element is almost vertical or is so long that the rotation point R It is located in front of the first wheel shaft 11 and the second wheel shaft 13 seen in the direction of travel, will act with a delayed position with respect to the wheels 19,

twenty-one. This also helps to optimize the pivoting capacity of the wheel suspension 1, that is to say when the two wheels 19, 21 are behind the rotation point R.

Figures 5a-5b show a basic diagram for ascending an obstacle 7. The front distance d between the first wheel axle 11 and the axis of rotation R is substantially greater than the rear distance c. This is to maintain the lever arm effect even when the wheel suspension 1 is ascending (see Figure 5b). By making the rear distance c smaller than the front distance d and by making the distance between the wheel shafts 11, 13 as small as possible, a good pivot function of the wheel suspension is achieved. The fact that the distance c is smaller makes it possible for the rotation point R, in the course of the ascent, to remain in its position below the rear wheel axle 13, keeping the lever arm b '', even slightly shorter that the lever arm b 'in the non-ascending position of the wheel suspension 1 (see reference symbols b' and b '' shown in Figures 5a and 5b).

The lever arm effect can thus be achieved even on a steep climb, substantially maintaining a distance b, since the rear distance c between the second wheel shaft 13

Figure 6 shows a fourth embodiment of the wheel suspension 1. The surface of the respective wheel 19, 21 has a peripheral surface 22 juxtaposed to contact the ground surface U (the roadway). The wheels 19, 21 are mounted on the wheel axles 11, 13 such that the peripheral surfaces 22 face each other. The tendency of the wheel assembly 1 to twist upon contact with an obstacle 7 is thus reduced, since the contact point of the front wheel 19 with the ground surface U and the pivot axis S have the minimum distance possible with each other.

Figure 7 shows a fifth embodiment of the wheel suspension 1. According to this embodiment, the front wheel 19 absorbing this first contact with the obstacle 7 has a larger diameter than the rear wheel 21. In the event that, in addition, the obstacle 7 is higher (see Figure 7) than the radius of the front wheel 19, the driving force Gx generates around the rotation point R and the lever arm b obtained for the suspension 1 of wheel a moment of rotation M, so that the front wheel 19 tends to raise the obstacle 7. The frame 3 is equipped with a stop element 25 (rubber block), which is arranged to engage with the connection element 9 to prevent the connection element 9 from turning over, that is to say so that the first shaft 11 Do not adopt the position of the second wheel axle 13 when a user lifts the vehicle. The wheel suspension is mounted on a manual off-road vehicle, such as a baby carriage or a jogging stroller (not shown).

A further preferred embodiment is shown schematically in Figure 8a-8c. Thanks to this embodiment, the tendency of the wheel assembly to be twisted (seen in the direction of travel) around the point of rotation is reduced, upon contact with an obstacle caused by force F. This is achieved by being the second distance c between the second wheel shaft 13 and the rotation point R greater than the first distance d between the first wheel shaft 11 and the rotation point R. Thanks to this embodiment, a greater part of the user's weight is distributed to the front wheel 19, with the result that a greater frictional force Ff is generated (see Figure 8c) (in the direction substantially transverse to the direction of travel) between the front wheel 19 and the floor surface 7. This reduces the tendency of the wheel suspension to twist around the pivot axis S at the moment when the rear wheel 21 (Figure 8c shows when the rear wheel 21 hits the obstacle with a force Fb). Figure 8d schematically shows in perspective a representation of the wheel suspension in Figure 8a.

A further embodiment is shown schematically in Figures 9a and 9b. An adjustable stop element 100 is attached to the pivot fork of the wheel suspension. Figure 9a shows the stop element 100 in its activated position, preventing rotation of the connecting arm counterclockwise when it locks the axle 13 of the rear wheel. The stopping element 100 limits the freedom of movement of the connecting arm 9, thereby preventing the front wheel 19 from touching the ground surface with the result that friction resistance against the ground surface is reduced, when orients around the pivot axis S, although the ability to overcome the obstacle of the wheel suspension is maintained. A resistor 101 is disposed in the shaft 13 of the rear wheel 21. Figure 9b shows the stop element 100 in its neutral position, allowing rotation (shown with reference RM) of the connecting arm 9 both counterclockwise and clockwise, which gives the wheel suspension a function of both overcome obstacles such as jumping (according to the initial description above). The frictional resistance increases against the ground surface since both wheels are now in contact with the ground, which also implies an inertia in the orientation, which may be preferred when the ground surface is irregular, and the vehicle becomes more directionally stable and the wheel does not "swing" from side to side in the lateral direction. As a result of the stopping element 100 being pushed down (as shown in Fig. 9a), the lever arm 9 is prevented from rotating forward (the same rotation as the wheel during travel in the direction of travel ) and the front wheel is therefore lifted from the ground surface, which gives an optimum pivoting capacity since only the rear wheel is supported against the ground surface (less friction with one wheel against the ground surface than with two wheels against the ground surface). The wheel suspension has maintained its ascent function, since the front wheel 19 (in the raised position) is arranged to rise such a distance from the ground surface that it can continue to come into contact with a possible obstacle.

A further embodiment is shown in Figure 10a and 10b schematically representing the wheel suspension arranged so that it cannot pivot in the horizontal plane. The first distance d between the first wheel shaft 11 and the rotation point R is the same size as the second distance c between the rotation point R and the second wheel shaft 13. The characteristics of overcoming obstacles are the same regardless of the direction of travel. The connecting element 9, which is rotatably arranged around the point of rotation R through two shafts 110 on a base plate 115, comprises three tabs 111 ', 111 ", 111"'. The tabs are rotatably arranged at the two ends of the shafts 110, with which the front wheel 19 and the rear wheel 21 can rotate around the rotation point R. The most powerful configured connection element with double fork fixation and its configuration with three tabs (M-shaped) and 110 short shafts provides high strength that allows a high load capacity. This embodiment is suitable for transport wheels or furniture wheels (transport cages, strollers, office and hospital furniture, etc.). This embodiment of the wheel suspension can also be configured so that it can pivot in the lateral direction by mounting on the upper side of the base plate 115.

The present invention should not be considered limited to the illustrative embodiments described before

5 riorior, but rather modifications and combinations thereof may appear within the scope of the present invention as defined in claim 1. The wheel suspension can be used in a walker, golf cart, baby carriage, carriage purchase, transport cars of various types, or other vehicles such as rail vehicles, funiculars, etc. The wheel suspension is not limited to being arranged so that it can pivot in the vehicle, for pivoting in the lateral direction. The wheel suspension comprising the pun