Guide bearing of rack of steering system

Abstract

To provide a solution to mounting and guidance of a rack.SOLUTION: A guide bearing of a rack for meshing a pinion and a rack of a steering system of a vehicle, comprises: a wall, a first portion of which is tubular, defining an axis of the guide bearing; and an internal channel around the axis opening at a first end of the guide bearing and opening on a second portion of the wall opposite to the first end in the axis of the guide bearing. The internal channel has a cross section transverse to the axis. The cross section is configured to enable insertion of the rack inside the internal channel according to an axis of the rack parallel to the axis of the guide bearing. The guide bearing comprises an inner surface of the internal channel of a first portion of the wall and an inner surface of a second portion of the wall of the guide bearing. The inner surfaces are arranged so as to be in slipping contact with a slipping surface of the rack opposite to a tooth part of the rack, when the rack is inserted into the internal channel of the first portion of the wall according to the axis of the rack.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to the technical field of an automotive rack steering system, and particularly to the attachment and guidance of a rack in a steering system.

Background Art

[0002] It is known to use a "pusher line", sometimes called a "pusher", to keep the rack in mesh contact with the steering pinion while compensating for tooth defects and wear. The pusher acts elastically on the rear of the rack in the region of the pinion to strongly press the teeth of the rack against the pinion. By the pusher, the meshing failure of the rack with the pinion is compensated, and this pusher also ensures the guidance of the rack while controlling the sliding force of the rack within the steering casing.

[0003] In the most common implementation, the pusher device comprises a pusher which is a part mounted so as to be translatable along a direction substantially perpendicular to the longitudinal axis of the rack in a cylindrical machined casing part, and this part is biased towards the rear of the rack by elastic means so as to press the rear face of the rack by a terminal part having an appropriate shape. The elastic means may be constituted by only a helical spring, or a metallic or elastomeric elastic washer, or a combination of such elastic members. These elastic means enable the setting of the springback (operating clearance of the new condition) of the pusher and are located under a metallic setting screw which constitutes the movement end stopper of the pusher.

Summary of the Invention

Problems to be Solved by the Invention

[0004] One drawback of such solutions is that the set of machinery formed by the rack, pinion, and pusher device is susceptible to shocks, and these shocks generate noise, particularly when rolling on paved roads or when reversing the steering. The shocks considered as sources of noise in this specification are: In the contact area of ​​the teeth of the rack and pinion, In the case of switching the pusher by toggle, at the contact point between the pusher itself and the inner wall of the corresponding cylindrical casing portion, When the pusher bounces back to the point of contact with the screw, it occurs in the contact area between the pusher itself and the setting screw.

[0005] Typically, an additional component called a noise suppression ring would have been added to suppress or limit these noise or vibration phenomena.

[0006] Another drawback of this pusher device is that it is expensive in terms of the number of parts required, the machining operations involved, and the setup and configuration required on the assembly line.

[0007] Another drawback is that applying considerable force to the rack to press the pinion generates significant friction, which can affect the driver's driving feel. For example, a feeling of sticking, or excessive filtering of information from the road.

[0008] Another drawback is the bulk of the pusher line. In fact, because the latter is positioned structurally perpendicular to the pinion, there are often issues with contact or proximity to other elements in the engine compartment, particularly the vehicle's cradle, which needs to provide a specific shape for its arrangement.

[0009] Therefore, the present invention aims to provide solutions to all or some of these problems. [Means for solving the problem]

[0010] For this purpose, the present invention relates to a guide bearing for a rack to engage a pinion and rack in a vehicle steering system, the guide bearing having a first portion that is tubular and comprising a wall defining an axis of the guide bearing and an internal channel around the axis that opens at a first end of the guide bearing and opens at a second portion of the wall opposite the first end on the axis of the guide bearing, the internal channel having a cross section that crosses the axis, the cross section being configured to allow the rack to be inserted into the internal channel according to the axis of the rack parallel to the axis of the guide bearing, and the guide bearing is in front of the first portion of the wall of the guide bearing The guide bearing comprises an inner surface of an internal channel and an inner surface of the second portion of the wall of the guide bearing, wherein both inner surfaces are arranged to slide in contact with the sliding surface of the rack opposite to the teeth of the rack when the rack is inserted into the inner channel of the first portion of the wall of the rack along the axis of the rack, the guide bearing comprises at least one damping means arranged at least partially around the guide bearing along a plane transverse to the axis of the guide bearing, the at least one damping means is arranged on the second portion of the wall, and the pinion is arranged opposite the inner surface of the second portion of the wall of the guide bearing to mesh with the teeth of the rack.

[0011] According to these configurations, the guide bearing is configured to ensure guidance and retention of the rack against the pinion, which is positioned opposite the inner surface of a second portion of the guide bearing wall so as to mesh with the teeth of the rack. In particular, the rack is pressed against the pinion, and wear that occurs following the operation of the mechanism is compensated by one or more damping elements of at least one damping means, and such compensation is more efficient because at least one damping element is positioned on the portion of the wall opposite to the pinion.

[0012] According to one embodiment, the present invention includes one or more of the following features, either individually or in a technically feasible combination:

[0013] According to one embodiment, the axis of the guide bearing and the axis of the rack are lateral to the axis of the pinion when the pinion is positioned to mesh with the teeth of the rack.

[0014] According to one embodiment, the axis of the guide bearing and the direction of extension of the guide bearing are substantially parallel, in other words, they form an angle between -10° and +10°, particularly between -5° and +5°, and more specifically between -2° and +2°.

[0015] According to one embodiment, the arrangement of the inner surfaces of the internal channels of the first part of the guide bearing wall and the inner surfaces of the internal channels of the second part of the guide bearing wall comprises at least one bearing surface disposed on the inner surface of the internal channels of the first part of the guide bearing wall and / or the inner surface of the second part of the guide bearing wall, wherein the at least one bearing surface is configured to slide in contact with the surface of the rack opposite to the teeth of the rack.

[0016] According to these configurations, the bearing surface of the guide bearing reduces the spread of the contact surface during the sliding of the rack, and therefore reduces friction.

[0017] According to one embodiment, at least one bearing surface is formed by an extra-thick portion on a part of the inner surface of the guide bearing wall.

[0018] According to one embodiment, the extra-thick portion has a curvature that follows a part of the plane transverse to the bearing axis, and the center of curvature of the curvature is eccentric with respect to the axis of the guide bearing.

[0019] According to one embodiment, the arrangement of the inner surfaces of the internal channels of the first portion of the guide bearing wall and / or the inner surfaces of the second portion of the guide bearing wall includes at least one groove disposed on the inner surfaces of the internal channels of the first portion of the guide bearing wall and / or the inner surfaces of the second portion of the guide bearing wall, the at least one groove being configured to receive a lubricant.

[0020] According to one embodiment, the guide bearing is made of a self-lubricating plastic material.

[0021] According to these configurations, the contact between the sliding surface of the rack and the inner surface of the internal channel of the first part of the wall of the guide bearing and / or the inner surface of the second part of the wall of the guide bearing becomes smoother.

[0022] According to one embodiment, the second part of the wall also forms a tube around the axis of the guide bearing, and the second part of the wall defines another internal channel that extends the internal channel defined by the first part of the wall. The other internal channel opens at the second end of the guide bearing, and the second end is on the opposite side of the first end of the guide bearing on the axis of the guide bearing. The second part of the wall is traversed by an external opening that leads to the other internal channel. The external opening is arranged on the second part of the wall on the opposite side of the inner surface of the second part of the wall with respect to the axis of the guide bearing, and the external opening is configured to accommodate the pinion.

[0023] According to one embodiment, the guide bearing further comprises at least one damping means arranged around the guide bearing according to a plane transverse to the axis of the guide bearing, at least in part.

[0024] According to these configurations, the play or wear located between the guide bearing and the steering casing to which the guide bearing is fixedly attached is compensated by damping means whose stiffness is adjusted during the setting of the guide bearing so that the rack is always properly pressed against the pinion.

[0025] According to one embodiment, the at least one damping means includes at least one annular-shaped damping element arranged around the guide bearing in a plane transverse to the axis of the guide bearing.

[0026] According to one embodiment, the at least one damping means includes a first damping element in a first cross-section located at one end of the guide bearing and a second damping element in a second cross-section located at the other end of the guide bearing.

[0027] According to one embodiment, the at least one damping means includes damping elements in a first cross-section located at one end of the guide bearing and / or in a second cross-section located at the other end of the guide bearing.

[0028] According to one embodiment, the damping element is a seal having a closed contour.

[0029] According to one embodiment, the seal is an O-ring gasket.

[0030] According to one embodiment, the seal is arranged to extend in a double groove arranged on a second part of the wall.

[0031] According to one embodiment, the at least one damping means includes an attachment made of a damper material, and the attachment is attached to all or part of the outer surface of the wall of the guide bearing by overmolding, adhesion, or a circlip.

[0032] According to one embodiment, the damping element is an O-ring gasket attached to an annular groove dug around the guide bearing.

[0033] According to one embodiment, the damping element is an O-ring gasket arranged to extend in a double groove arranged on the wall of the guide bearing, for example, on a second part of the wall.

[0034] According to one embodiment, the at least one damping means includes an overmold having a damper material, for example, a polymer foam, and the overmold is attached onto all or part of the outer surface of the wall surface of the guide bearing.

[0035] With these configurations, once the rack is inserted into the internal channel of the first part of the wall along the axis of the rack, the rack is pressed against the pinion, and any wear that may occur following the operation of the mechanism is compensated by the damping element of at least one damping means.

[0036] According to one embodiment, the guide bearing is configured to be fixedly mounted to the steering casing of the steering system, and the guide bearing further comprises an angular indexing element, which is configured to cooperate with a complementary element of the steering casing to define the angular position of the guide bearing around the axis of the guide bearing.

[0037] According to one embodiment, the angular index element is a projection that protrudes from the outer surface of the guide bearing wall.

[0038] According to one embodiment, the guide bearing comprises a clip element positioned on the outer surface of the wall, the clip element being configured to cooperate with other complementary elements of the steering casing to hold the guide bearing within the steering casing.

[0039] According to one embodiment, other complementary elements of the steering casing include grooves machined into the steering casing, rings fitted into the steering casing, or circlips within the steering casing.

[0040] According to one embodiment, the guide bearing further comprises at least one slot opening onto an internal channel of the guide bearing, the slot traversing the wall in the direction of extension of the guide bearing, and the slot is configured to allow elastic deformation of the wall due to the influence of pressure exerted on the outer surface of the wall, the elastic deformation resulting in a narrowing of a portion of the wall in a plane traversing the axis of the guide bearing.

[0041] These configurations facilitate the insertion of the guide bearing into the steering casing.

[0042] According to one embodiment, the clip element is positioned on the outer surface of the wall and, in cooperation with complementary elements of the steering casing, is configured to hold a guide bearing clipped into the steering casing by the biasing effect of elastic deformation obtained by the pressure applied to the outer surface of the wall.

[0043] In these configurations, the guide bearing is clipped in place within the steering casing.

[0044] According to one embodiment, the guide bearing includes at least one groove formed on the outer surface of the wall in order to soften the tubular wall.

[0045] According to one embodiment, at least one groove is a slot that opens into an internal channel and / or other internal channels of the guide bearing.

[0046] According to these configurations, the grooves consisting of slots provide flexibility to the guide bearing structure, which in turn reduces wear-related clearances in the guide bearing.

[0047] According to one embodiment, at least one groove is formed between two extra-thick portions on the outer surface of at least one portion of the wall.

[0048] These configurations make it possible to control at least one damping direction by restricting a certain degree of freedom of deformation of the guide bearing.

[0049] According to one embodiment, the guide bearing further comprises at least one arrangement of the central portion of the wall of the guide bearing, the central portion being positioned on a portion of the wall corresponding to the inner surface of a second portion of the wall of the guide bearing.

[0050] According to these configurations, the arrangement is configured to form a softer central portion on the opposite side of the pinion when the pinion is housed within the external opening.

[0051] According to one embodiment, at least one arrangement comprises slots around the central portion of the wall.

[0052] According to one embodiment, at least one arrangement includes a predetermined thickness in the central portion of the wall.

[0053] According to one embodiment, the guide bearing further comprises a stroke limiter, which is configured to limit the stroke of the rack when the rack is inserted into the guide bearing.

[0054] According to one embodiment, the stroke limiter is integrated with the first end of the guide bearing.

[0055] With these configurations, the stroke limiter avoids metal-to-metal contact between the axial ball joint case and the steering casing.

[0056] According to one embodiment, the first part of the wall and the second part of the wall are separate and configured to be assembled.

[0057] According to one embodiment, the first part and the second part are configured to be assembled by clipping the first part to the second part, or by ultrasonic welding between the first part and the second part.

[0058] According to one embodiment, the first part and the second part are assembled by placing the first part in a recess of the cavity of an injection molding die and overmolding the second part by injection within the injection molding die.

[0059] According to one embodiment, the first part and the second part are made from different plastic materials, and as a result, the wear resistance of each part differs from that of the other, and the wear resistance of each part is suited to the operating stress of each part. [Brief explanation of the drawing]

[0060] For a better understanding, one embodiment of the present invention and / or implementation will be described, as non-limiting examples, with reference to the accompanying drawings, each representing an embodiment or implementation of the apparatus and / or method according to the present invention. Elements denoted by the same reference numeral in the drawings refer to similar elements or elements having similar functions. [Figure 1] Figure 1 is a perspective view of a guide bearing according to one embodiment of the present invention. [Figure 2a] Figure 2a is a perspective view of a guide bearing including two separable parts. [Figure 2b] Figure 2b is a perspective view of the guide bearing according to the embodiment of Figure 2a, in which two separable parts are assembled to form the guide bearing according to the present invention. [Figure 3] Figure 3 is a perspective view of the guide bearing according to the embodiment of Figure 1, mounted on a rack that meshes with the pinion. [Figure 4] Figure 4 is a perspective view of a guide bearing according to another embodiment, mounted on a rack that meshes with a pinion. [Figure 5] Figure 5 is another perspective view of the guide bearing according to the embodiment of Figure 4, mounted on the rack that meshes with the pinion. [Figure 6] Figure 6 is a perspective view of the guide bearing according to the embodiment shown in Figures 4 and 5. [Figure 7] Figure 7 is a perspective view of a guide bearing according to another embodiment of the present invention. [Figure 8] Figure 8 is a perspective view of a guide bearing according to another embodiment of the present invention. [Figure 9] Figure 9 is a perspective view of a guide bearing according to another embodiment of the present invention. [Figure 10] Figure 10 is a perspective view of a guide bearing according to another embodiment of the present invention. [Figure 11] Figure 11 is a perspective view of a guide bearing according to another embodiment of the present invention. [Figure 12] Figure 12 is a perspective view of a guide bearing according to one embodiment of the present invention. [Figure 13] Figure 13 is a perspective view of a means for achieving orientation, which is used herein and is represented on a known anti-noise ring. [Figure 14] Figure 14 is a perspective view of a guide bearing according to one embodiment of the present invention. [Figure 15] Figure 15 is a perspective view of a guide bearing according to one embodiment of the present invention, and corresponds to the embodiment shown in Figure 12 from a different angle. [Figure 16] Figure 16 is a cross-sectional view of the guide bearing according to the embodiment of Figure 1, which is mounted on the steering casing. [Modes for carrying out the invention]

[0061] Next, an embodiment of the guide bearing 1 according to the present invention will be described with reference to Figure 1.

[0062] The guide bearing 1 in Figure 1 is mounted to the casing 14 of the vehicle's steering system, as shown in Figure 16, and is intended to receive the rack 2 to engage with the teeth of the pinion 3 and the rack 2.

[0063] The guide bearing 1 comprises a wall 10, and the wall 10 comprises a first portion 10' and a second portion 10''.

[0064] The first portion is tubular and defines the axis of the guide bearing 1 and an internal channel 9 around the axis, the internal channel 9 opening at the first end 18 of the guide bearing 1 and the internal channel 9 opening in a second portion 10" of the wall 10 opposite to the first end 18 on the axis of the guide bearing 1. The internal channel 9 has a cross section that spans the axis of the guide bearing 1, and this cross section is configured to allow the rack 2 to be inserted into the internal channel 9 according to the axis of the rack 2 which is parallel to the axis of the guide bearing 1.

[0065] The guide bearing 1 comprises an inner surface of an internal channel 9 of a first portion 10' of the wall 10 and an inner surface of a second portion 10" of the wall 10, wherein the inner surface is positioned to slide in contact with the sliding surface of the rack 2 when the rack is inserted into the internal channel 9 of the first portion 10' of the wall 10 along the axis of the rack 2, and the sliding surface is on the opposite side of the teeth of the rack 2.

[0066] By convention, the inner surface of the first portion 10' or the second portion 10'' is referred to as the surface of the wall 10 that receives the so-called sliding surface of the rack 2 and is positioned to slide in contact with the said sliding surface.

[0067] According to these configurations, the guide bearing is configured to ensure that the rack is guided so as to engage with the teeth of the rack 2, and that the rack is held against the pinion positioned opposite the inner surface of the second portion 10" of the wall 10 of the guide bearing 1, as shown in Figures 3 and 16.

[0068] In particular, the axis of the guide bearing and the axis of the rack are lateral to the axis of the pinion when the pinion is positioned to mesh with the teeth of the rack.

[0069] According to one embodiment, the axis of the guide bearing and the direction of extension of the guide bearing are substantially parallel, in other words, they form an angle between -10° and +10°, particularly between -5° and +5°, and more specifically between -2° and +2°.

[0070] In particular, the arrangement of the inner surfaces of the internal channels 9 of the first portion 10' and the second portion 10" of the wall 10 of the guide bearing 1 comprises at least one bearing surface 15, 17 positioned on the inner surface of the internal channel 9 of the first portion 10' and / or the inner surface of the second portion 10" of the wall 10 of the guide bearing 1, wherein at least one bearing surface is configured to slide in contact with the surface of the rack 2 opposite to the teeth of the rack 2.

[0071] According to these configurations, the bearing surfaces 15 and 17 of the guide bearing 1 reduce the spread of the contact surface during the sliding of the rack, and therefore reduce friction.

[0072] More specifically, at least one bearing surface 15, 17 is formed by an extra-thick portion on a part of the inner surface of the wall of the guide bearing 1.

[0073] More specifically, the extra-thick portions 15 and 17 have a curvature that follows a portion of the plane traversing the axis of the guide bearing 1, and the center of the curvature is eccentric with respect to the axis of the guide bearing 1.

[0074] According to another embodiment, the arrangement of the inner surfaces of the internal channels 9 of the first portion 10' of the wall 10 of the guide bearing 1 and the inner surfaces of the second portion 10" of the wall 10 of the guide bearing 1 includes at least one groove 20 located on the inner surface of the internal channels 9 of the first portion 10' of the wall 10 and / or on the inner surface of the second portion 10" of the wall 10, the at least one groove 20 being configured to receive a lubricant, which is, for example, grease applied to the sliding surface of the rack.

[0075] Advantageously, the guide bearing may also be made from a self-lubricating plastic material.

[0076] With these configurations, contact between the sliding surface of the rack and the inner surface of the internal channel 9 of the first portion 10' of the wall 10 and / or the inner surface of the second portion 10" of the wall 10 becomes more slippery.

[0077] According to a second embodiment shown in detail in Figures 4 to 15 relating to a different variation, and particularly with reference to Figure 6, the guide bearing 1 comprises a second portion 10" of a wall 10 that is tubular around the axis of the guide bearing 1, the second portion 10" of the wall 10 defines another internal channel 9' that extends an internal channel 9 defined by a first portion 10' of the wall 10, the other internal channel 9' opens at a second end 19 of the guide bearing 1, the second end 19 is on the axis of the guide bearing 1 opposite to the first end 18 of the guide bearing 1, the second portion 10" of the wall 10 is traversed by an external opening 8 leading to the other internal channel 9', the external opening 8 is located on the second portion 10" of the wall 10 on the opposite side of the inner surface of the second portion 10" of the wall 10 with respect to the axis of the guide bearing 1, and the external opening 8 is configured to accommodate a pinion 3, particularly as shown in Figures 4 and 5.

[0078] In particular, in Figure 5, the external opening 8 connects to another internal channel 9' of the guide bearing 1 on the side of the teeth of the rack 2, and the teeth of the pinion 3 engage with the teeth of the rack 2 when the pinion 3 is received into the external opening 8.

[0079] To properly hold the rack 2, which is inserted into the guide bearing 1 and in contact with the pinion 3, at least one damping means 4, 4', 4'' is provided when the guide bearing is mounted to the steering casing 14. The damping means is at least partially arranged around the guide bearing 1 according to a plane that crosses the axis of the guide bearing 1.

[0080] In these configurations, any operating clearance or wear between the guide bearing and the steering casing to which the guide bearing is fixedly mounted is compensated by damping means whose stiffness is adjusted during the setup of the guide bearing so that the rack is always properly pressed against the pinion.

[0081] According to one embodiment, the damping means includes at least one annular damping element arranged around the guide bearing in a plane transverse to the axis of the guide bearing.

[0082] In particular, in a method conforming to the second embodiment of the guide bearing shown in Figure 6, the damping means comprises a first damping element 4 in a first cross-section located at the first end 18 of the guide bearing 1, and a second damping element 4 in a second cross-section located at the second end 19 of the guide bearing.

[0083] For example, the damping element 4 may be an O-ring gasket fitted into an annular groove carved around the guide bearing.

[0084] In particular, according to one embodiment adapted to the first embodiment shown in Figure 1, the damping element 4" is an O-ring gasket positioned to extend within a double groove located on the wall 10 of the guide bearing 1, specifically on the second portion 10" of the wall 10.

[0085] According to one embodiment, the damping means comprises an attachment 4' made of a damper material, such as polymer foam, which is attached to all or part of the outer surface of the wall 10 of the guide bearing 1 by overmolding, bonding, or clipping, as shown in one embodiment in Figure 8.

[0086] According to these configurations, when the rack is inserted into the internal channel 9 of the first portion 10' of the wall 10 along the axis of the rack 2, the rack is pressed against and held by the pinion 3, and any wear that may occur following the operation of the mechanism is compensated by damping elements of at least one damping means 4, 4', 4''.

[0087] To clarify the angular position of the guide bearing 1 relative to the steering casing 14 of the steering system around the axis of the guide bearing 1, the guide bearing 1 may be provided with an angular index element 12, which is configured to cooperate with a complementary element 13 of the steering casing 14.

[0088] For example, the angular index element 12 is a projection that protrudes from the outer surface of the wall 10 of the guide bearing, as shown in Figures 1, 16, and 13, which correspond to two different embodiments of the guide bearing according to the present invention.

[0089] To ensure proper retention of the guide bearing 1 within the casing 14, clip elements 21 can be positioned on the outer surface of the wall 10, and the clip elements 21 are configured to cooperate with other complementary elements of the steering casing 14, such as grooves machined within the steering casing, to hold the guide bearing within the steering casing 14. This embodiment is shown in particular in Figures 1 and 16.

[0090] In particular, according to another embodiment shown in Figures 6 and 8 to 12, the guide bearing 1 includes a slot 6 opening onto an internal channel 9 of the guide bearing 1, the slot 6 traversing the wall 10 in the direction of extension of the guide bearing 1, and the slot 6 is configured to allow elastic deformation of the wall 10 due to the influence of pressure exerted on the outer surface of the wall 10, the elastic deformation resulting in a narrowing of a portion of the wall in a plane traversing the axis of the guide bearing 1.

[0091] These configurations facilitate the insertion of the guide bearing into the steering casing.

[0092] Furthermore, the clip element 21, positioned on the outer surface of the wall 10 and configured to cooperate with complementary elements of the steering casing, contributes to holding the guide bearing 1, which is clipped into the steering casing 14, by the biasing effect of elastic deformation obtained by the pressure applied to the outer surface of the wall 10.

[0093] In these configurations, the guide bearing is clipped in place within the steering casing.

[0094] According to one embodiment, the guide bearing includes at least one groove 7 formed on the outer surface of the wall in order to soften the tubular wall of the wall 10, particularly the second portion 10''.

[0095] According to one embodiment, at least one groove 7 is a slot that opens into an internal channel 9 and / or other internal channel 9' of the guide bearing.

[0096] According to these configurations, the grooves 7, which consist of slots, provide flexibility to the guide bearing structure, and this flexibility allows for a reduction in wear-related clearances of the guide bearing.

[0097] According to one embodiment, at least one groove 7 is formed between two extra-thick portions 5' on the outer surface of at least one portion 10', 10'' of the wall 10.

[0098] These configurations make it possible to control at least one damping direction by restricting a certain degree of freedom of deformation of the guide bearing.

[0099] Furthermore, in order to form a soft central portion of the guide bearing 1 on the opposite side of the pinion 3 when the pinion 3 engages with the teeth of the rack 2, the guide bearing 1 comprises at least one arrangement 7' of the central portion of the wall 10 of the guide bearing 1, according to embodiments shown in more detail in Figures 14 and 15, wherein the central portion is located on a part of the wall 10 corresponding to the inner surface of a second portion 10" of the wall 10 of the guide bearing 1. Thus, this central portion is located opposite the pinion 3 that engages with the teeth of the rack 2.

[0100] According to the embodiment shown in Figure 14, the arrangement includes slots around the central portion of the wall.

[0101] According to the embodiment shown in Figure 15, the arrangement includes a predetermined thickness in the central portion of the wall.

[0102] To avoid metal-to-metal contact between the axial ball joint case and the steering casing, the guide bearing 1 includes a stroke limiter 16, particularly according to the embodiments shown in Figures 6, 8-12, 14, and 15, the stroke limiter 16 being configured to limit the stroke of the rack 2 when the rack 2 is inserted into the guide bearing 1.

[0103] For example, the stroke limiter 16 is integrated with the first end 18 of the guide bearing 1.

[0104] In particular, Figures 1, 7, and 11 show embodiments of the guide bearing 1 that do not include the stroke limiter 16.

[0105] The first portion 10' and the second portion 10'' of the wall 10 of the guide bearing 1 according to the present invention may be separate and configured to be assembled.

[0106] For example, as shown in Figures 2a and 2b, the first portion 10' and the second portion 10'' of the wall 10 may be configured to be assembled by clipping the first portion to the second portion.

[0107] According to another embodiment, the first portion 10' and the second portion 10'' of the wall 10 may be configured to be assembled by ultrasonic welding between the first portion and the second portion.

[0108] According to another embodiment, the first and second parts are assembled by placing the first part in a recess of the cavity of an injection molding die and overmolding the second part by injection within the injection molding die.

[0109] In particular, the two parts of the bearing may be made from two different plastic materials, and these materials may include carbon fiber type reinforcements, so that each of the two parts can have different wear resistances.

Claims

1. A guide bearing (1) of a rack (2) for meshing a pinion (3) and the rack (2) of a vehicle steering system, wherein the guide bearing (1) has a first part (10') thereof being tubular, a wall (10) defining an axis of the guide bearing (1), and an internal channel (9) that opens at a first end (18) of the guide bearing (1) and opens at a second part (10") of the wall (10) opposite to the first end (18) on the axis of the guide bearing (1) around the axis, the internal channel (9) has a cross-section transverse to the axis, and the cross-section is configured such that the rack (2) can be inserted inside the internal channel (9) along an axis of the rack (2) parallel to the axis of the guide bearing (1), the guide bearing (1) includes an inner surface of the internal channel (9) of the first part (10') of the wall (10) of the guide bearing (1) and an inner surface of the second part (10") of the wall (10) of the guide bearing (1), and both inner surfaces are arranged to be in sliding contact with a sliding surface of the rack (2) opposite to a tooth part of the rack (2) when the rack is inserted inside the internal channel (9) of the first part (10') of the wall (10) along the axis of the rack (2), the guide bearing (1) includes at least one damping means (4', 4") arranged at least partially around the guide bearing (1) according to a plane transverse to the axis of the guide bearing (1), the at least one damping means (4', 4") is arranged on the second part (10") of the wall (10), and the pinion is arranged to face an inner surface of the second part (10") of the wall (10) of the guide bearing (1) so as to mesh with the tooth part of the rack (2).

2. In the guide bearing (1) according to claim 1, The second part (10”) of the wall (10) is also tubular around the axis of the guide bearing (1), and the second part (10”) of the wall (10) defines another internal channel (9’) that extends the internal channel (9) defined by the first part (10’) of the wall (10). The other internal channel (9’) opens at the second end (19) of the guide bearing (1), and the second end (19) is on the opposite side of the guide bearing (1) from the first end (18) on the axis of the guide bearing (1). The second part (10”) of the wall (10) is traversed by an external opening (8) that communicates with the other internal channel (9’). The external opening (8) is disposed in the second part (10”) of the wall (10) on the opposite side of the inner surface of the second part (10”) of the wall (10) with respect to the axis of the guide bearing (1). The external opening (8) is a guide bearing configured to accommodate the pinion (3).

3. In the guide bearing (1) according to claim 1 or 2, The guide bearing, wherein the at least one damping means comprises damping elements (4) at a first cross-section located at one end (18) of the guide bearing and / or at a second cross-section located at the other end (19) of the guide bearing.

4. In the guide bearing (1) according to claim 3, The guide bearing, wherein the damping element is a seal having a closed contour.

5. In the guide bearing (1) according to claim 4, The guide bearing, wherein the seal is an O-ring gasket.

6. In the guide bearing (1) according to claim 4, The guide bearing, wherein the seal (4”) is arranged to extend in a double groove disposed on the second part (10”) of the wall (10).

7. In the guide bearing (1) according to claim 1, The guide bearing, wherein the at least one damping means comprises an attachment (4’) made of a damper material, and the attachment is attached to all or part of the outer surface of the wall (10) of the guide bearing (1) by overmolding, adhesion, or clip fastening.

8. In the guide bearing (1) according to claim 1, The guide bearing is configured to be fixedly attached to a steering casing (14) of the steering system. The guide bearing (1) further comprises an angular indexing element (12), and the indexing element (12) is configured to cooperate with a complementary element (13) of the steering casing (14) so as to define the angular position of the guide bearing (1) around the axis of the guide bearing (1).

9. In the guide bearing (1) according to claim 8, it comprises a clip element (21) arranged on the outer surface of the wall (10), and the clip element (21) is configured to cooperate with other complementary elements of the steering casing (14) to hold the guide bearing within the steering casing (14).

10. In the guide bearing (1) according to claim 2, it further comprises at least one slot (6) opening onto the internal channel (9) of the guide bearing. The slot (6) traverses the wall (10) in the direction of extension of the guide bearing (1), and the slot (6) is configured to allow elastic deformation of the wall (10) under the influence of the pressure exerted on the outer surface of the wall (10). The elastic deformation results in narrowing a portion of the wall in a plane transverse to the axis of the guide bearing (1).

11. In the guide bearing (1) according to claim 1, it further comprises at least one arrangement (7’) in a central portion of the wall (10) of the guide bearing (1), and the central portion is arranged in a part of the wall (10) corresponding to the inner surface of the second portion (10”) of the wall (10) of the guide bearing (1).

12. In the guide bearing (1) according to claim 1, it further comprises a stroke limiter (16), and the stroke limiter (16) is configured to limit the stroke of the rack when the rack is inserted into the guide bearing.

13. In the guide bearing (1) according to claim 1, A guide bearing in which the first part (10') of the wall (10) and the second part (10") of the wall (10) are separate and configured to be assembled.