Elastomeric bearings for the elastic mounting of a ball joint and ball joint system

Abstract

Elastomeric bearing (12) for the elastic mounting of a ball joint (10) in a receiving eye (14) of a chassis (16), comprising an inner sleeve (28) receiving the ball joint (10), an outer sleeve (32) surrounding the inner sleeve (28) forming a gap (30), and an elastomeric body (34) arranged within the gap (30) which connects the inner sleeve (28) and the outer sleeve (32), wherein the elastomeric body (34) has at least one radial pad (58) acting in a radial direction (R), and at least two axial pads (60, 62) which are axially opposed to each other (A) and act in opposite axial directions (A), wherein a first axial pad (60) is preloaded against a first axial pad inner surface (70) of the outer sleeve (32) and a first axial pad outer surface (72) of the inner sleeve (28). isand wherein a second axial pad (62) bears under preload against a second axial pad inner surface (74) of the outer sleeve (32) and a second axial pad outer surface (76) of the inner sleeve (28), characterized in that the outer sleeve (32) has a radially inwardly projecting projection (56) which forms the axial pad inner surfaces (70, 74).

Description

[0001] The present invention relates to an elastomeric bearing for the elastic mounting of a ball joint in a mounting eye of a chassis, comprising an inner sleeve receiving the ball joint, an outer sleeve surrounding the inner sleeve forming a gap, and an elastomeric body arranged within the gap, which connects the inner sleeve and the outer sleeve to each other. The invention further relates to a ball joint system for a chassis comprising a ball joint and an elastomeric bearing.

[0002] Ball joints in a chassis are used to transmit both steering and suspension movement to a component that moves about two axes, such as a ball joint to connect a control arm to a steering knuckle, or a tie rod end to connect a tie rod to a McPherson strut or steering knuckle.

[0003] A conventional ball joint has a ball-shaped head and a socket that receives the ball head. The ball head can rotate freely in all directions within the socket.

[0004] Ball joints in the suspension are elastically mounted via an elastomer bearing to dampen vibrations caused by road surface irregularities and acting on the ball joint. Furthermore, an elastomer bearing reduces the secondary spring rate at small amplitudes, as high secondary spring rates occur at small amplitudes due to the breakaway torque of the ball joint. In addition, the compliance of elastomer bearings allows for targeted manipulation of the axle kinematics during compression, such as oversteer or understeer. This is not possible with a rigid connection using a ball joint. Consequently, by supplementing a ball joint with a surrounding elastomer bearing, the additional compliance can be used to influence these properties.

[0005] From KR 10 2017 0 063 066 A, an elastomeric bearing for a ball joint is known, comprising an inner sleeve, an outer sleeve surrounding the inner sleeve, and an elastomeric body arranged between them, connecting the inner and outer sleeves. The known elastomeric bearing is not capable of absorbing high cardanic moments. Furthermore, the elastomeric bearing does not exhibit a linear radial stiffness characteristic, but rather a highly progressive one. Other elastomeric bearings are known, for example, from DE 10 2017 219 373 A1, DE 41 38 582 C1, or DE 196 27 753 A1.

[0006] The challenge lies in the high moments acting on the ball joints. These moments must be transmitted by the elastomer bearing within a very limited axial installation space. Therefore, a strongly progressive, cardan-like behavior is necessary for these elastomer bearings. Furthermore, low radial stiffness with initially linear behavior is required for decoupling. A strongly progressive radial stiffness characteristic of the elastomer bearing is also necessary to ensure tight wheel guidance and direct steering.

[0007] The invention is based on the objective of creating an elastomeric bearing and a ball joint system that can absorb high cardanic moments, have improved progressive cardanic behavior and also have a linear, radial stiffness characteristic.

[0008] To solve the problem, an elastomeric bearing with the features of claim 1 and a ball joint system with the features of claim 12 are proposed.

[0009] Advantageous embodiments of the elastomeric bearing are the subject of the dependent claims.

[0010] An elastomeric bearing for the elastic mounting of a ball joint in a mounting eye of a chassis comprises an inner sleeve receiving the ball joint, an outer sleeve surrounding the inner sleeve forming a gap, and an elastomeric body arranged within the gap, which connects the inner sleeve and the outer sleeve to each other, wherein the elastomeric body has at least one radial pad acting in a radial direction and at least two axial pads that are axially opposed to each other and act in opposite axial directions, wherein a first axial pad bears under preload against a first axial pad inner surface of the outer sleeve and a first axial pad outer surface of the inner sleeve, wherein a second axial pad bears under preload against a second axial pad inner surface of the outer sleeve and a second axial pad outer surface of the inner sleeve.and wherein the outer sleeve has a radially inwardly projecting projection which forms the axial pad inner surfaces.

[0011] Due to two axially pre-stressed axial pads, the elastomer bearing exhibits highly progressive gimbal behavior. Unlike conventional axial stops, these pads do not engage only after a certain deflection; rather, even in the unloaded initial position, the two axially pre-stressed pads already contribute significantly to the axial characteristics of the elastomer bearing. As a result, the areas of the diagonally opposing axial pads that are under compression during gimbal deflection of the elastomer bearing also provide the necessary high gimbal stiffness. This high gimbal stiffness also ensures that no or only minimal stick-slip effects occur due to the interaction of the breakaway torque of the ball joint and the gimbal compliance of the elastomer bearing.Since the surfaces on which the axial pads rest are integrated into the outer sleeve, the elastomer bearing is very short and can be pressed into a receiving eye from both sides.

[0012] In an advantageous embodiment, each of the axial pad inner surfaces is inclined at a maximum of 20°, and in particular a maximum of 10°, to a plane perpendicular to the axial direction. This allows the axial pads to make a negligible contribution to the radial stiffness of the elastomer bearing. Advantageously, the axial pad inner surfaces are inclined radially outwards by a maximum of 20°, and in particular a maximum of 10°, to a plane perpendicular to the axial direction. The plane perpendicular to the axial direction runs radially.

[0013] In an advantageous embodiment, the inner surfaces of the axial pads are oriented perpendicular to the axial direction. This means that the axial pad is subjected only to shear stress during radial deflection of the bearing. Furthermore, since the axial pads are only bonded on one side, either to the outer or inner sleeve, they can only transmit very small shear forces. Consequently, the axial pads contribute very little to the radial stiffness of the elastomeric bearing, so that the radial stiffness characteristic of the elastomeric bearing is determined by the radial pad.

[0014] In an advantageous embodiment, the radial pad rests under preload against an inner radial pad surface of the inner sleeve and an outer radial pad surface of the outer sleeve. This radial preload of the radial pad results in a linear, radial stiffness characteristic. The radial pad is preloaded during the pressing of the elastomer bearing into a receiving eye.

[0015] The outer sleeve has a radially inwardly projecting projection that forms the inner surfaces of the axial pads. This integrates the surfaces for the axial pads into the outer sleeve, resulting in a short elastomeric bearing. In an advantageous embodiment, the axially pointing end faces of the projection form the inner surfaces of the axial pads. Furthermore, the projection advantageously forms the outer surface of the radial pads. In particular, the radially pointing end face of the projection forms the outer surface of the radial pads.

[0016] In an advantageous embodiment, the inner sleeve has a radially outwardly projecting collar at each of its ends, the collars forming the outer surfaces of the axial pads. Advantageously, the projection is arranged between the collars, with a first axial gap formed between the first inner surface and the first outer surface of the axial pads, within which the first axial pad is arranged, and with a second axial gap formed between the second inner surface and the second outer surface of the axial pads, within which the second axial pad is arranged.

[0017] In an advantageous embodiment, at least one of the collars is designed as a disc which is secured to the inner sleeve by means of a locking element. When the disc is secured to the inner sleeve, the two axial pads are pre-tensioned. Advantageously, the locking element is secured to the ball joint, in particular to a ball joint cup. Advantageously, the disc is designed as a perforated disc. This allows the disc to be slid onto the ball joint, in particular to a ball joint cup. In an advantageous embodiment, the locking element is a snap ring. Advantageously, the snap ring engages in a groove provided in the ball joint, in particular in the ball joint cup. Furthermore, advantageously, both collars can be designed as a disc, with each disc being secured to the inner sleeve by means of a locking element, in particular a snap ring.

[0018] In an advantageous embodiment, a radial clearance is formed between the inner and outer sleeves, with the inner and / or outer sleeves forming a radial end stop that limits the movement from the inner to the outer sleeve and vice versa. The end stops thus absorb the high radial loads by limiting the radial movement. Consequently, due to the pre-stressed radial cushion, the elastomeric bearing initially exhibits a linear stiffness characteristic in the radial direction until the radial end stop engages to absorb and counteract the high radial loads. Furthermore, the radial end stop can advantageously be covered with an elastomeric stop cushion to achieve a progressive stiffness characteristic. Preferably, the stop cushion is formed from the same elastomer as the elastomeric body.

[0019] In an advantageous embodiment, the collars form the radial end stop. Thus, the collars absorb the high radial loads. Advantageously, the end faces of the collars facing the outer sleeve and / or the outer sleeve itself can be coated with an elastomeric stop pad.

[0020] In an advantageous embodiment, the inner sleeve and / or the outer sleeve is formed in multiple parts. If the inner sleeve is multi-part, the axial cushions can be pre-tensioned in a defined manner. Advantageously, the inner sleeve and / or the outer sleeve are formed in two parts.

[0021] In an advantageous embodiment, the elastomer body is bonded to the inner sleeve and / or the outer sleeve in a materially bonded manner.

[0022] In an advantageous embodiment, the outer surfaces and inner surfaces of the axial cushions are arranged within the receiving eye. This results in a compact and short design for the elastomeric bearing, allowing it to be pressed into the receiving eye from both sides.

[0023] According to another aspect, a ball joint system for a chassis is proposed, comprising a ball joint and an elastomer bearing. Advantageously, the ball joint further comprises a ball joint head, a ball joint cup for receiving the ball joint head, at least one sliding element arranged between the ball joint head and the ball joint cup, and at least one fixing element that secures the ball joint head and the sliding element within the ball joint cup. Advantageously, the ball joint further comprises an elastomer membrane that seals around the ball joint head and is fixed to the ball joint cup. The elastomer membrane protects the ball joint from environmental influences, particularly from contamination.

[0024] The following section explains an elastomeric bearing, a ball joint system, and other features and advantages in more detail using exemplary embodiments, which are schematically illustrated in the figures. These show: Fig. 1 a longitudinal section through a ball joint system which is received in a receiving eye of a chassis and which has a ball joint and an elastomer bearing according to a first embodiment; Fig. 2 a longitudinal section through a ball joint system which is received in a receiving eye of a chassis and which comprises a ball joint and an elastomer bearing according to a second embodiment; and Fig. 3 a longitudinal section through a ball joint system which is received in a receiving eye of a chassis and which has a ball joint and an elastomer bearing according to a third embodiment.

[0025] In Fig. Figure 1 shows a ball joint system 10 comprising a ball joint 11 and an elastomer bearing 12. The ball joint 11 is elastically mounted in a mounting eye 14 of a suspension assembly 16 via the elastomer bearing 12. The suspension assembly 16 can, for example, be part of a suspension linkage or part of a chassis.

[0026] The ball joint 11 has a ball joint head 18 which is arranged within a sleeve-shaped ball joint cup 20. Two sliding elements 22 are arranged between the ball joint head 18 and the ball joint cup 20, which allow a rotational movement of the ball joint head 18 relative to the ball joint cup 20.

[0027] The ball joint head 18 and the sliding elements 22 are secured in the ball joint cup 20 by a fixing element 24. Specifically, the fixing element 24 is pressed into the ball joint cup 20 or secured there by means of a fixing element (not shown). To protect the ball joint 11 from contamination, an elastomer membrane 26 is provided, which is attached at its end to a circumferential rim 27 of the ball joint cup 20 and seals against the ball joint head 18.

[0028] The elastomer bearing 12 has an inner sleeve 28, an outer sleeve 32 surrounding the inner sleeve 28 forming a gap 30 and an elastomer body 34 arranged within the gap 30, which connects the inner sleeve 28 and the outer sleeve 32.

[0029] The inner sleeve 28 is made of metal or plastic, in particular fiber-reinforced plastic, and accommodates the ball joint 10. For this purpose, the ball joint cup 20 is inserted into the inner sleeve 28. To secure the ball joint 10, a recess 38 is provided at a first end 36 of the inner sleeve 28, into which a shoulder 40 projecting from the ball joint cup 20 is inserted.

[0030] As in Fig. As can be seen in Figure 1, the inner sleeve 28 has a first collar 42 projecting outwards in the radial direction R at its first end 36, which is spaced apart from the outer sleeve 32. At a second end 44 of the inner sleeve 28, a disc 46 is arranged, which forms a second collar 48 projecting outwards in the radial direction R, which is also spaced apart from the outer sleeve 32. The disc 46 is secured to the inner sleeve 28 by means of a locking element 50, which in this case is a snap ring 52, by the snap ring 52 engaging in a groove 54 provided in the ball joint cup 20.

[0031] The outer sleeve 32 is made of metal or plastic, in particular fiber-reinforced plastic, and is formed in one piece. The elastomer bearing 12 is connected to the chassis 16 via the outer sleeve 32, by pressing the outer sleeve 32 into the receiving eye 14 of the chassis 16. The outer sleeve 32 has a radially inward-projecting projection 56 in its center, located between the two collars 42, 48.

[0032] The projection 56 is spaced apart from the two collars 42, 48, with a first axial gap 57 formed between the projection 56 and the first collar 42, and with a second axial gap 59 formed between the projection and the second collar 48. As further shown in Fig. As can be seen in Figure 1, the projection 56 is spaced apart from the inner sleeve 28, with a radial gap 61 being formed between the projection 56 and the inner sleeve 28.

[0033] The elastomer body 34 is bonded to the outer sleeve 32 and has a radial pad 58 acting in the radial direction R, a first axial pad 60 acting in the axial direction A, a second axial pad 62 which is spaced axially from the first axial pad 60 and acts in the opposite axial direction A, and two stop pads 64.

[0034] The radial pad 58 is arranged in the radial gap 61 and rests under preload against an outer radial pad surface 66 formed by the projection 56 and an inner radial pad surface 68 formed by the inner sleeve 28. The radial pad 58 is bonded to the outer radial pad surface 66, for example by vulcanization. The radial pad 58 is preloaded when the elastomer bearing 1 is pressed into the receiving eye 14.

[0035] The first axial pad 60 is arranged in the first axial gap 57 and rests under preload against a first axial pad inner surface 70 formed by the projection 56 and a first axial pad outer surface 72 formed by the first collar 42. The first axial pad 60 is bonded to the first axial pad inner surface 70, for example by means of vulcanization.

[0036] The second axial pad 62 is arranged in the second axial gap 59 and rests under preload against a second axial pad inner surface 74 formed by the projection 56 and a second axial pad outer surface 76 formed by the second collar 48. The second axial pad 62 is bonded to the second axial pad inner surface 74, for example by means of vulcanization.

[0037] As in Fig. As can be seen in Figure 1, the two axial pad inner surfaces 70, 74 are perpendicular to the axial direction A. Therefore, the axial pads 60, 62 make a negligible contribution to the radial stiffness of the elastomer bearing 12.

[0038] The two axial pads 60, 62 are pre-tensioned during the assembly of the disc 46 by sliding the disc 46 onto the ball joint cup 20 and securing it by means of the snap ring 52.

[0039] Since the axial pads 60, 62 are pre-stressed, they already contribute significantly to the axial properties of the elastomer bearing 12 in the unloaded initial position. As a result, the areas of the diagonally opposite axial pads 60, 62 that are subjected to pressure during a gimbal deflection of the elastomer bearing 12 also provide the necessary high gimbal stiffness of the elastomer bearing 12. This high gimbal stiffness is required to prevent or minimize stick-slip effects resulting from the interaction of the breakaway torque of the ball joint head 18 and the gimbal compliance of the elastomer bearing 12. Because the inner surfaces 70, 74 of the axial pads are integrated into the outer sleeve 3, to which the axial pads 60, 62 can be bonded, the elastomer bearing 12 is very short and can also be pressed into the receiving eye 14 from both sides.

[0040] The radial clearance R between the outer sleeve 32 and the collars 42, 48 allows the inner sleeve 28 to move radially R relative to the outer sleeve 32 and vice versa, with the collars 42, 48 acting as a radial end stop 78. Under high radial loads, the radial end stop 78 limits movement of the inner sleeve 28 to the outer sleeve 32 and vice versa, with the stop pads 64 damping the movement.

[0041] Thus, the radially preloaded radial pad 58 initially results in a relatively linear radial stiffness characteristic of the elastomeric bearing 12, before the stiffness characteristic of the radial pad 58 becomes more progressive with increasing deflection and finally the radial end stop 78 engages to absorb the high radial loads. The maximum radial forces are transferred externally at the elastomeric bearing 12 by the two collars 42, 48.

[0042] Further embodiments of the elastomer bearing 12 are described below, using the same reference numerals for identical and functionally equivalent parts.

[0043] In Fig. Figure 2 shows a second embodiment of the elastomeric bearing 12, which differs from the first embodiment in that the radial cushion 58 is bonded to both the inner sleeve 28 and the outer sleeve 32. Furthermore, both collars 42, 48 are formed from discs 46. The disc 46 forming the first collar 42 is arranged between the inner sleeve and the shoulder 40, and the disc 46 forming the second collar 48 is, as in the first embodiment, fixed to the inner sleeve by means of the snap ring 52. As also shown in Fig. As can be seen in Figure 2, the inner sleeve 28 is designed as a simpler and therefore more cost-effective pipe section.

[0044] In Fig. Figure 3 shows a third embodiment of the elastomer bearing 12, which differs from the other two embodiments in that the inner sleeve 28 and the elastomer body 34 are two-part. The inner sleeve 28 has two congruent inner sleeve sections 80, each inner sleeve section 80 having a collar 42, 48, each of which is covered with a stop pad 64. The elastomer body 34 also has two congruent elastomer body sections 82, which are, in this case, metallurgically bonded to the inner sleeve 28. Due to the two-part construction of the inner sleeve 28 and the elastomer body 34, the axial pads 60, 62 can be pre-tensioned in a defined manner in the axial direction A. As shown in Figure 3, the inner sleeve 28 and the elastomer body 34 are two-part. Fig. As can be seen in Figure 3, the inner sleeve 28 is fixed to the ball joint cup 20 by means of the snap ring 52.

[0045] Furthermore, it is also conceivable that the inner sleeve 28 is a single piece with the elastomer body 34 bonded to it in a materially bonded manner, and that the outer sleeve 32 is in two parts and is placed around the inner assembly consisting of the inner sleeve 28 and the elastomer body 34 during assembly.

Claims

[1] Elastomeric bearing (12) for the elastic mounting of a ball joint (10) in a receiving eye (14) of a chassis (16), comprising an inner sleeve (28) receiving the ball joint (10), an outer sleeve (32) surrounding the inner sleeve (28) forming a gap (30), and an elastomeric body (34) arranged within the gap (30) which connects the inner sleeve (28) and the outer sleeve (32), wherein the elastomeric body (34) has at least one radial pad (58) acting in a radial direction (R), and at least two axial pads (60, 62) which are opposed to each other in the axial direction (A) and act in opposite axial directions (A), wherein a first axial pad (60) is preloaded against a first axial pad inner surface (70) of the outer sleeve (32) and a first axial pad outer surface (72) of the inner sleeve (28) is locatedand wherein a second axial pad (62) is under preload against a second axial pad inner surface (74) of the outer sleeve (32) and a second axial pad outer surface (76) of the inner sleeve (28), characterized by , that the outer sleeve (32) has a radially inwardly projecting projection (56) which forms the axial pad inner surfaces (70, 74). [2] Elastomeric bearing (12) according to claim 1, characterized by , that each of the axial pad inner surfaces (70, 74) is inclined at a maximum of 20° to a plane that is perpendicular to the axial direction (A). [3] Elastomeric bearing (12) according to claim 1 or 2, characterized by , that the axial pad inner surfaces (70, 74) are aligned perpendicular to the axial direction (A). [4] Elastomeric bearing (12) according to any one of the preceding claims, characterized by , that the radial pad (58) is under preload against a radial pad inner surface (68) of the inner sleeve (28) and a radial pad outer surface (66) of the outer sleeve (32). [5] Elastomeric bearing (12) according to any one of the preceding claims, characterized by , that the inner sleeve (28) has at its ends (36, 44) a collar (42, 48) projecting outwards in the radial direction (R), wherein the collars (42, 48) form the axial pad inner surfaces (70, 74). [6] Elastomeric bearing (12) according to claim 5, characterized by , that at least one of the collars (42, 48) is designed as a disc (46) which is fixed to the inner sleeve (28) by means of a locking element (50). [7] Elastomeric bearing (12) according to any one of the preceding claims, characterized by , that a free path in the radial direction (R) is formed between the inner sleeve (28) and the outer sleeve (32), wherein the inner sleeve (28) and / or the outer sleeve (32) form a radial end stop (78) that limits the movement from inner sleeve (28) to outer sleeve (32) and vice versa. [8] Elastomeric bearing (12) according to claim 7, characterized by, that the collars (42, 48) form the radial end stop (78). [9] Elastomeric bearing (12) according to any one of the preceding claims, characterized by that the inner sleeve (28) and / or the outer sleeve (32) is formed in multiple parts. [10] Elastomeric bearing (12) according to any one of the preceding claims, characterized by , that the elastomer body (34) is bonded to the inner sleeve (28) and / or the outer sleeve (32) in a materially bonded manner. [11] Elastomeric bearing (12) according to any one of the preceding claims, characterized by , that the axial pad outer surfaces (72, 76) and the axial pad inner surfaces (70, 74) are arranged within the receiving eye (14). [12] Ball joint system (10) for a chassis (16) comprising a ball joint (11) and an elastomer bearing (12) according to any one of claims 1 to 11.

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