Rolling bearing, in particular for steering column, having axial stop
By introducing bearing raceways and thrust surface structures into the steering column rolling bearing, the problem of free play of the bearing under load is solved, the axial stiffness is increased and the movement is restricted, thus improving the stability of the steering column.
Patent Information
- Application Number
- CN202510273295.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-03-13
- Filing Date
- 2025-03-10
- Publication Date
- 2025-09-16
AI Technical Summary
Existing steering column rolling bearings have free play under axial and radial loads and are unable to completely restrict the axial and radial movements between the rings.
A rolling bearing structure is designed, in which the first ring is provided with a bearing raceway and a thrust surface, the thrust surface having a concave inner profile in a straight section and extending obliquely to form an axial stop portion, limiting the relative axial and radial movement between the first ring and the second ring, and applying a force in the axial direction through a prestressing element.
It increases the axial stiffness of the bearing, limits axial and radial movement, and improves the stability and durability of the steering column.
Smart Images
Figure CN120650325A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of rolling bearings, in particular rolling bearings for steering columns of motor vehicles. Background Art
[0002] A steering column generally comprises a shaft, one end of which is fixedly attached to a drive steering wheel actuated by the driver of the vehicle, and the other end of which is fixedly attached to a mechanical member intended to ensure the angular positioning of the vehicle's wheels. The shaft of the steering column is rotatably mounted in a tubular housing via two rolling bearings.
[0003] One type of rolling bearing for a steering column comprises an inner ring, an outer ring, and rows of balls arranged between the bearing races of the rings. At least one of the rings comprises a casing and an insert element arranged in the casing to form the bearing races of the ring. This results in a rolling bearing with three or four contact points, capable of functioning under axial and / or radial loads. Typically, such a bearing also includes an elastic prestress element mounted inside the casing and bearing axially against one of the insert elements to achieve a function with limited movement.
[0004] This rolling bearing architecture allows to avoid the presence of free play in the bearing, but does not completely restrict the axial and radial movements between the rings, even when the bearing preload is adjusted after mounting.
[0005] The object of the present invention is therefore to remedy these drawbacks. Summary of the Invention
[0006] The subject of the invention is a rolling bearing, in particular for a steering column, comprising a first ring, a second ring and at least one row of balls arranged between the rings, the second ring comprising a casing, at least one insert element arranged in the casing for forming a bearing raceway for the second ring, and at least one prestressing element mounted in the casing and exerting an axial force on the insert element.
[0007] An "insert element" is an element that is separate from the housing.
[0008] According to general characteristics, the first ring is provided with a bearing raceway having a concave inner profile in a straight section, and at least one first thrust surface, which extends obliquely toward the outside in the direction of the second ring from a first axial end of the bearing raceway.
[0009] The thrust surface forms a slope change relative to the bearing raceway in the region where it connects to the raceway.
[0010] The thrust surface forms an axial stop that allows the axial movement of the balls in the row to be blocked. Thus, the relative axial and radial movement between the first and second rings is limited. This also allows the axial stiffness of the bearing to be increased.
[0011] Advantageously, said thrust surface of said first ring is in the form of a frustoconical cone.
[0012] In a straight section, the thrust surface of the first ring preferably extends perpendicularly to an inclined straight line joining the first axial end of the bearing raceway and the contact point between the ball and an insert element of the second ring, the insert element being axially located on the side opposite to the thrust surface relative to the ball.
[0013] Advantageously, the first ring comprises an annular surface from which the bearing raceway is formed and to which the thrust surface is connected.
[0014] In one embodiment, the thrust surface is connected to the annular surface via a chamfer.
[0015] Advantageously, in a straight section, the thrust surface extends obliquely from the first axial end, from one side of the concave inner contour of the bearing raceway.
[0016] In one embodiment, the first ring comprises a second thrust surface which extends obliquely towards the outside in the direction of the second ring from a second axial end of the bearing raceway opposite the first axial end.
[0017] The second thrust surface of the first ring is preferably symmetrical to the first thrust surface about a radial plane passing through the center of the ball.
[0018] In one embodiment, the second ring comprises two insert elements arranged in the casing on either side of a radial plane passing through the center of the ball.
[0019] Advantageously, the two insert elements of the second ring are identical.
[0020] In one embodiment, the first ring is an inner ring of the rolling bearing and the second ring is an outer ring of the rolling bearing.
[0021] The invention also relates to a steering column comprising a housing, a shaft coaxial with the housing, and at least one rolling bearing as defined above, mounted radially between the housing and the shaft. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Other objects, characteristics and advantages of the present invention will emerge on reading the following description, given purely as a non-limiting example, and with reference to the accompanying drawings, in which:
[0023] Figure 1 is an axial cross-sectional view of a rolling bearing according to an exemplary embodiment;
[0024] Figure 2 yes Figure 1 Detailed view of
[0025] Figure 3 is a detailed cross-sectional view of a rolling bearing according to another exemplary embodiment; and
[0026] Figure 4 is a detailed cross-sectional view of a rolling bearing according to yet another exemplary embodiment. DETAILED DESCRIPTION
[0027] Figure 1 A rolling bearing, designated by reference numeral 1, is shown and includes a first race 2, a second race 3, and balls 4 arranged in a row between the races 2 and 3. In this embodiment, the rolling bearing 1 includes a cage 5 radially arranged between the races 2 and 3 to maintain regular circumferential spacing between the balls 4. Alternatively, the rolling bearing 1 may be devoid of the cage 5.
[0028] In this embodiment, the first ring 2 is the inner ring of the rolling bearing 1 and the second ring 3 is the outer ring of the rolling bearing 1 .
[0029] The inner ring 2 comprises a cylindrical hole and an outer axial annular surface 6, which is axially delimited by opposite radial front faces, from which a circular annular groove is formed, which has a concave inner profile in straight section suitable for forming a bearing raceway 7 for the ball 4, the groove being oriented radially towards the outside.
[0030] As will be described in more detail below, the inner ring 2 includes thrust surfaces 13a, 13b for limiting the movement of the balls 4 along the thrust surfaces 13a, 13b in the axial direction.
[0031] The inner ring 2 is solid. A "solid ring" refers to a ring whose form is obtained by machining with chip removal (turning, grinding) from a tube, a bar, a forging billet and / or a rolled billet.
[0032] The outer ring 3 comprises an outer housing 8 and two separate insert elements 9, 10 forming the bearing raceways of the ring 3 for the balls 4. The insert elements 9, 10 are here in the form of two separate beads. The outer ring 3 also comprises a prestressing element 11 that applies an axial force to one of the insert elements 9, 10. The insert elements 9, 10 and the prestressing element 11 are mounted inside the housing 8.
[0033] The housing 8 can advantageously be manufactured by cutting and deep drawing sheet metal. The annular housing 8 comprises an outer axial portion 12a, radially inwardly extended at each end by radial portions 12b, 12c. Insert elements 9, 10 are arranged to radially contact the bore of the axial portion 12a and are disposed in the housing 8 on either side of a radial plane P passing through the center of the ball 4. The radial portion 12c has a smaller radial dimension than that of the radial portion 12b and also has a reduced thickness, resulting in a slight inward curvature toward the ball 4, so that the radial portion 12c rests against the insert element 10 and axially prestresses the bearing 1. The cage 5 is disposed radially between the free edge of the radial portion 12c of the housing 8 and the outer surface of the inner ring 2.
[0034] The housing 8 further comprises an inner axial portion 12d which extends the smaller diameter edge of the radial portion 12b in the axial direction towards the inside. The axial portion 12d is provided for centering the prestressing element 11 inside the housing 8.
[0035] An annular prestressing element 11 is mounted axially in contact with the radial portion 12b of the housing 8 and the insert element 9, and is radially mounted between the outer axial portion 12a and the inner axial portion 12d, while remaining at a distance from the outer axial portion 12a and the inner axial portion 12d. The radial surface of the prestressing element 11 is in axial contact with the inner surface of the radial portion 12b, and the opposite radial surface is in axial contact with the insert element 9. The prestressing element 11 is spaced apart from the ball 4. The prestressing element 11 exerts a permanent axial force on the insert element 9, which tends to preload the ball 4 onto the other insert element 10 and the groove of the inner ring 2.
[0036] The prestressing element 11 is advantageously formed of an elastic material (e.g. an elastomer, such as nitrile rubber or polyurethane). In the embodiment shown, the prestressing element 11 is in the form of a torus with a square cross section. As a variant, a prestressing element 11 with another profile (e.g. a circle) in a straight cross section can be provided.
[0037] The side rings 9, 10 are each in the form of a split ring and are mounted inside the housing 8, in direct contact therewith. The balls 4 are arranged between the side rings 9, 10 of the outer ring 3 (forming the bearing raceways) and the bearing raceway 7 of the inner ring 2. This creates a rolling bearing 1 with three contact points. In the exemplary embodiment shown, the side rings 9, 10 are identical to reduce manufacturing costs.
[0038] like Figure 2 As more clearly shown in FIG, the bearing raceway 7 of the inner ring is provided with a first axial end e1 and a second axial end e2 that define the axial length of the bearing raceway 7. The first axial end e1 and the second axial end e2 are offset relative to the outer axial annular surface 6 in the radial direction on the side opposite to the outer ring 3 (i.e., toward the inside). The first axial end e1 and the second axial end e2 are aligned relative to the axial direction.
[0039] The first axial end e1 is axially located on the same side as the prestressing element 11 with respect to a radial plane P passing through the center of the ball 4 , and the second axial end e2 is axially located on the opposite side.
[0040] The inner ring 2 includes a first annular thrust surface 13a, which is frustoconical and extends obliquely outward from the first axial end e1 of the bearing raceway 7 in the direction of the outer ring 3 as far as the outer axial annular surface 6. The thrust surface 13a is connected on one side to the outer axial annular surface 6 of the inner ring 2 and on the other side to the bearing raceway 7. The thrust surface 13a thus extends between the first axial end e1 of the bearing raceway 7 and the annular surface 6 of the inner ring 2. The thrust surface 13a may also be connected to the annular surface 6 via a chamfer.
[0041] In a straight section, the thrust surface 13a extends obliquely from the first axial end e1 inside the concave inner contour of the bearing raceway 7. In other words, the thrust surface 13a closes toward the inside of the circular arc of the bearing raceway 7.
[0042] In a straight section, the thrust surface 13a intersects an inclined straight line d1, which connects the first axial end e1 of the bearing raceway 7 of the inner ring 2 and the contact point between the ball 4 and the axially opposing insert element 10. The angle formed between the thrust surface 13a and this inclined straight line d1 can, for example, be between 25° and 85°. The inner ring 2 also includes a second thrust surface 13b, which extends obliquely from the second axial end e2 of the bearing raceway 7, in the direction of the outer ring 3, as far as the outer axial annular surface 6. The thrust surface 13b is connected to the outer axial annular surface 6 of the inner ring 2 on one side and to the bearing raceway 7 on the other side. Thus, the second thrust surface 13b extends between the second axial end e2 of the bearing raceway 7 and the annular surface 6 of the first inner ring 2. The thrust surface 13b may also be connected to the annular surface 6 via a chamfer.
[0043] In a straight section, the thrust surface 13b extends obliquely from the second axial end e2 inside the concave inner contour of the bearing raceway 7. In other words, the thrust surface 13b is closed toward the inside of the circular arc of the bearing raceway 7.
[0044] In a straight section, the thrust surface 13b intersects an inclined straight line d2 that engages the second axial end e2 of the bearing raceway 7 of the inner ring 2 and the contact point between the ball 4 and the axially opposite insert element 9. The angle formed between the thrust surface 13b and this inclined straight line d2 can be, for example, between 25° and 85°.
[0045] The thrust surfaces 13 a , 13 b may be symmetrical with respect to a radial plane P passing through the center of the ball 4 .
[0046] These surfaces 13 a , 13 b of the inner ring form axial stops, allowing the axial movement of the row of balls 4 to be blocked.
[0047] In this exemplary embodiment, the outer ring 3 comprises two insert elements 9 , 10 in a housing, the insert elements 9 , 10 taking the form of side rings for forming the bearing raceways of the outer ring.
[0048] As a further alternative, other designs of the outer ring can be provided.
[0049] For example, Figure 3 As shown, in which identical elements carry the same reference numerals, the outer ring 3 comprises an insert element 9 having a cup-shaped form, which defines a bearing raceway for the balls 4 .
[0050] exist Figure 4 In the exemplary embodiment shown, in which identical elements carry the same reference numerals, the outer ring 3 comprises a single insert element 10 in the form of a cup, which defines a bearing raceway for the balls 4, and the housing 8 comprises an inclined extension 12 d extending obliquely from the inner axial portion 12 c and defining a bearing raceway for the balls 4. In this example, a prestressing element 11 is arranged axially between the radial portion 12 c of the housing and the insert element 10.
[0051] As indicated above, in the exemplary embodiment shown, the first ring 2 of the bearing is the inner ring, and the second ring 3 is the outer ring. Alternatively, a reverse configuration can be provided, in which the first ring 2 is the outer ring and the second ring 3 is the inner ring. In this case, the bearing raceway 7 and the one or more thrust surfaces 13a, 13b are formed on the bore of the outer ring, which forms the inner surface of the ring.
Claims
1. A rolling bearing (1), in particular for a steering column, comprising a first ring (2), a second ring (3) and at least one row of balls (4) arranged between the rings (2, 3), the second ring (3) comprising a housing (8), at least one insert element (9) arranged in the housing (8) for forming a bearing raceway for the second ring (3), and at least one prestressing element (11) mounted in the housing (8) and exerting an axial force on the insert element (9), characterized in that The first ring (2) is provided with a bearing raceway (7) having a concave inner profile in a straight section, and at least one first thrust surface (13a) extending obliquely toward the outside in the direction of the second ring (3) from a first axial end (e1) of the bearing raceway (7).
2. The bearing (1) according to claim 1, characterized in that The thrust surface (13a) of the first ring (2) is in the form of a frustoconical cone.
3. The bearing (1) according to any one of claims 1 or 2, characterized in that The first ring (2) comprises an annular surface (6), the bearing raceway (7) is formed from the annular surface (6), and the thrust surface (13a) is connected to the annular surface (6).
4. The bearing (1) according to any one of claims 1 to 3, characterized in that In a straight section, the thrust surface (13a) extends obliquely from the first axial end (e1) inside the concave inner contour of the bearing raceway (7).
5. The bearing (1) according to any one of claims 1 to 4, characterized in that The first ring (2) comprises a second thrust surface (13b) which extends obliquely outward in the direction of the second ring (3) from a second axial end (e2) of the bearing raceway (7) opposite the first axial end (e1).
6. The bearing (1) according to claim 5, characterized in that The second thrust surface (13b) of the first ring (2) is symmetrical to the first thrust surface (13a) about a radial plane (P) passing through the center of the ball (4).
7. The bearing (1) according to any one of claims 1 to 6, characterized in that The second ring (3) comprises two insert elements (9, 10) arranged in the housing (8) on either side of a radial plane (P) passing through the center of the ball (4).
8. The bearing (1) according to any one of claims 1 to 7, characterized in that The first ring (2) is the inner ring of the rolling bearing (1), and the second ring (3) is the outer ring of the rolling bearing (1).
9. A steering column comprising a housing, a shaft coaxial with the housing, and at least one rolling bearing (1) according to any one of claims 1 to 8, the rolling bearing (1) being mounted radially between the housing and the shaft.