Bearing units and steering gears

Abstract

The invention relates to a bearing arrangement (16, 31, 41, 51, 64) for supporting a worm (4) of a steering gear (48) on a steering gear housing (49) of the steering gear (48), comprising: at least one radial bearing (17, 34, 43, 53, 65) connected to the worm (4) in a rotationally fixed manner, and at least one retaining element (21, 55, 67), which connects the radial bearing (17, 34, 43, 53, 65) to the steering gear housing (48) and is of elastic construction. In order to provide a bearing arrangement (16, 31, 41, 51, 64) which is optimized with respect to the required structural space and is more durable and has reduced play, a retaining element (21, 55, 67) is connected on the radial bearing side only to the outer cover surface (22) of an outer bearing ring (19, 33, 46, 52, 66) of a radial bearing (17, 34, 43, 53, 65) and is fixed to the outer cover surface (22) of the outer bearing ring (19, 33, 46, 52, 66) in an axially non-movable manner relative to the longitudinal center axis (23) of the radial bearing (17, 34, 43, 53, 65).

Description

Technical Field

[0001] The present invention relates to a bearing device for supporting a worm of a steering gear on a steering gear housing of the steering gear, the bearing device having at least one radial bearing connected to the worm in a rotationally fixed manner and at least one elastically constructed retaining element connecting the radial bearing to the steering gear housing. The present invention also relates to a steering gear for an electric power steering system of a vehicle, the steering gear having a steering gear housing, a worm arranged in the steering gear housing, and at least one bearing device, the worm being rotatably supported on the steering gear housing via the bearing device. Background Art

[0002] An electric power steering system of a vehicle is used to reduce the effort involved in steering the steering wheel of the vehicle. To this end, the electric power steering system supports the driver during steering by using the electric motor of the electric power steering system to augment the steering effort applied by the driver. The electric motor drives a steering gear of the electric power steering system, which is generally in the form of a worm gear. The electric motor drives in particular a worm of the steering gear, which meshes with a worm wheel connected to a steering column of the motor vehicle.

[0003] The worm of a steering gear is usually supported rotatably at one end by a fixed bearing and at the other end by a movable bearing on the steering gear housing of the steering gear. In the area of ​​the movable bearing or the fixed bearing, the worm is generally positioned with a force in the direction of the worm wheel in order to ensure an optimal contact between the thread of the worm and the tooth arrangement of the worm wheel over the long term. In this case, the contact forces between the worm and the worm wheel are optimally adjusted, so that the friction between the worm and the worm wheel can be reduced and the NVH characteristics (noise / vibration / harshness characteristics) as well as the durability of the steering gear can be improved.

[0004] Different embodiments of a steering gear worm bearing in a steering gear housing of a steering gear are known. One of these embodiments uses a fixed bearing on the drive side, with which the worm is prestressed in the direction of the worm wheel. The fixed bearing has a radial bearing, which is arranged in a radial bearing housing made of sheet metal. The radial bearing housing connects the radial bearing to the steering gear housing. The radial bearing housing has an elastic section, with which tolerances and influences due to environmental reasons of temperature / humidity and, in some cases, due to wear can be compensated. The movable bearing holds the other end of the worm and can be constructed in any way so that the mobility of the worm is limited in order to limit NVH effects and to ensure a stable meshing of the worm in the worm wheel over the service life of the steering gear.

[0005] Patent document US 8 667 858 B2 relates to a steering gear with a helical pinion, which can be connected to a drive device via a shaft and in which the helical gear meshes. The steering gear has a bearing for the shaft at the drive-side end of the shaft, which is configured as a fixed bearing and has a first roller bearing for supporting the shaft. The steering gear has a bearing device at the free end of the helical pinion, which is configured as a movable bearing and has a second roller bearing for supporting the helical gear. The bearing of the shaft has a retaining member, which is installed in the housing part of the steering gear and has a recess, which allows the pivoting movement of the annular part of the retaining member installed with the first roller bearing. The retaining member has a disc-shaped part, which is provided with a recess, and the annular part can pivot relative to the recess. The annular part is installed together with the outer ring of the first roller bearing, and the disc-shaped part is fixed to the housing part, or the annular part is installed together with the inner ring of the first roller bearing, and the disc-shaped part is fixed to the shaft.

[0006] Patent document DE 10 2009 015 025 B4 relates to a roller bearing device having a rolling surface element, a connecting element, and a disk-shaped elastic element, on which a rolling member for rolling is arranged, the connecting element having a hollow cylindrical portion, which firmly abuts against an outer cover of the rolling surface element and protrudes at one axial end into a circumferential portion axially beyond the rolling surface element, the disk-shaped elastic element having a cylindrical central recess and protruding radially outwardly beyond the other elements in a flange-like manner and being fixed in the protruding area. The elastic element has two annular plates, which are arranged concentrically relative to each other and connected to each other at least at two circumferential areas separated from each other. The protruding piece of the connecting element is configured to extend only in the circumferential area, in which the elastic element has no connection with the two annular plates.

[0007] Patent document DE 10 2007 023 456 A1 relates to a bearing arrangement for supporting a shaft at a first bearing position and a second bearing position, the second bearing position being axially spaced from the first bearing position and each position having a bearing. At least one of the bearings is arranged by means of an elastic device in relation to the housing so that the bearing can be redirected in radial direction against the elastic force of the elastic device. The elastic device is designed as a sleeve-like element, wherein the sleeve-like element has, over at least a portion of its circumference, a portion which is designed in radial cross section at least in the manner of a quarter circle.

[0008] Patent document DE 10 2008 042 281 A1 relates to a shaft bearing in a steering system, the system having a ball bearing, the ball bearing having an outer ring and having an inner ring for supporting the shaft, wherein the outer ring is supported in a housing part of the steering system. The shaft bearing has a retaining member, which can be connected to the shaft and receives the inner ring of the ball bearing. The retaining member has a recess, which allows at least the movement of the portion of the retaining member receiving the inner ring of the ball bearing.

[0009] Patent document US 9 102 351 B2 relates to an electric power steering device in which the clearance of the output shaft of the electric motor is suppressed in a stable manner for a long time to reduce vibration and disruptive noise occurring during operation. The front end portion of the output shaft and the end of the worm are connected to each other in a manner that can transmit torque and can be relatively displaced in the axial direction. An elastic element is provided in the connection portion between the output shaft and the worm, and the elastic element has an elastic force in a direction that separates the output shaft and the worm. Due to the elastic force of the elastic element, the pretensioning action acts together with the contact angle arranged in series on a pair of ball bearings that support the output shaft relative to the housing of the electric motor, in such a way that the output shaft can rotate freely.

[0010] Patent document US 8 567 553 B2 relates to a reduction gear mechanism connected to an electric motor. The reduction gear mechanism has a first bearing and a first elastic element, the first bearing rotatably supports the first end of the worm so that the worm can swing around the first end in a swinging direction, and the first elastic element elastically pushes the second bearing in a direction that reduces the axial spacing between the worm and the turbine. The first end of the electric motor and the output shaft are connected by a connecting portion. The second elastic element arranged between the connecting portion and the first end pushes the worm toward the second end and applies a pre-tensioning effect to the first bearing. The outer ring of the first bearing is axially inserted into the third elastic element and the fourth elastic element.

[0011] Patent document DE 20 2016 103 802 U1 relates to a gear unit for a motor vehicle, which has a worm, which can rotate about an axially extending rotation axis and is supported on a housing via a rotary bearing, which can pivot about a pivot axis and is received in a fixed pivot ring with a spherical outer surface. The gear unit also has an elastic element, which extends at least partially tangentially about the rotation axis and is supported on the housing in the axial direction on the one hand, and on the rotary bearing on the other hand by means of two abutment parts, which are opposite to each other in the direction of the pivot axis and protrude axially. Summary of the invention

[0012] The object of the present invention is to provide a bearing arrangement of the type mentioned in the introduction which is optimized with regard to the required installation space and is more durable and has reduced play.

[0013] According to the invention, this object is achieved by a bearing arrangement having the features of claim 1, wherein the retaining element is connected on the radial bearing side only to the outer cover surface of the outer bearing ring of the radial bearing and is fixed to the outer cover surface of the outer bearing ring in an axially non-movable manner relative to the longitudinal center axis of the radial bearing.

[0014] It should be noted that the features and measures listed individually in the following description can be combined with one another in any technically advantageous manner and describe further embodiments of the invention. The description further describes the features of the invention and explains the invention, in particular in conjunction with the drawings.

[0015] According to the invention, the retaining element is connected only to the outer cover surface of the outer bearing ring of the radial bearing, wherein the retaining element and the outer bearing ring are configured in such a way that the retaining element is fixed to the outer cover surface of the outer bearing ring in an axially immovable manner relative to the longitudinal center axis of the radial bearing. Preferably, the retaining element is releasably fixed to the outer cover surface of the outer bearing ring without being destroyed, thereby simplifying the assembly of the bearing arrangement and, for example, making it possible to simply replace components of the bearing arrangement.

[0016] Therefore, unlike the situation in patent document US 8 667 858 B2, according to the invention, the radial bearing is not arranged in a radial bearing housing in the bearing device. This has the advantage that the required stiffness or the required mobility of the radial bearing and thus the worm can be ensured more reliably during the service life of the bearing device. In addition, the disadvantage of conventional radial bearing housings is that, for example, only a limited degree of clearance freedom between the radial bearing and the radial bearing housing and due to bending can be generated. When using a radial bearing housing, the clearance required to be set between the radial bearing and the radial bearing housing limits the required deformation of the bearing. In addition, the stiffness of the radial bearing housing changes during the service life of the corresponding conventional bearing device, so that the performance of the conventional bearing device deteriorates. In addition, in the corresponding conventional bearing device, it is difficult to ensure pretensioning, especially pretensioning of the worm, over the entire operating range. In addition, the presence of the radial bearing housing limits the available structural space, thereby limiting the function of the bearing.

[0017] These disadvantages do not occur in the bearing device according to the invention, because the conventional radial bearing housing is replaced by a retaining element, by which the radial bearing can be connected to the steering gear housing. By omitting the conventional radial bearing housing, the rigidity and prestressing of such a radial bearing housing in the bearing device according to the invention do not fluctuate. In addition, in particular, since there is no gap between the radial bearing and the retaining element in the bearing device according to the invention, fluctuations in the gap of the radial bearing housing do not have to be taken into account in the bearing device according to the invention. The structural space obtained due to the absence of the radial bearing housing can be used to provide a radial bearing with higher productivity, so that high tilting moments or radial forces caused by the prestressing generated by the retaining element and the prestressing operating force in the mutually meshing tooth structure of the worm and the worm wheel can be maintained. Therefore, a significant advantage of the present invention is that the radial bearing and the retaining element are connected to each other without gap, and the rigidity of the connection can be kept constant over the entire service life of the bearing device. In addition, unlike conventional bearing devices with a radial bearing housing in the bearing device, according to the present invention, no additional prestressing elastic element is required to maintain the prestressing during the service life of the bearing device.

[0018] The friction in the radial bearing can thus be kept constant by the bearing arrangement according to the invention, since the radial bearing cannot be deformed by the radial bearing housing. The durability of the bearing arrangement according to the invention is thereby improved. Furthermore, in the bearing arrangement according to the invention, the positioning of the radial bearing or the worm relative to the worm wheel can be improved, thereby ensuring constant properties of the bearing arrangement. In particular, fluctuations regarding the bearing position can be overcome. Furthermore, the bearing arrangement according to the invention can be produced with less complexity and using fewer components, which involves a reduction in costs and weight.

[0019] The radial bearing can be configured as a radial roller bearing or as a radial sliding bearing. Furthermore, the radial bearing can have the function of an axial bearing in order to fix the worm against movement in the direction of its longitudinal center axis. The radial bearing also has an inner bearing ring, which is connected to the worm in a rotationally fixed manner. To this end, the worm can have a threaded portion and a bearing journal, the threaded portion cooperating with the worm wheel of the steering gear, the bearing journal being axially adjacent to the threaded portion and one of the bearing journals being connected to the inner bearing ring in a rotationally fixed manner.

[0020] The retaining element is made of metal or a metal alloy, in particular steel. Due to the elastic deformation of the retaining element in the functionally fitted state, a pre-tensioning of the radial bearing or the worm in the direction of the worm wheel is generated. This pre-tensioning can be adjusted in particular by the material properties of the retaining element, the geometrical construction of the retaining element, the position of the worm axis relative to the worm wheel axis and the axial positioning of the retaining element relative to the radial bearing. For example, the retaining element can be connected to the radial bearing eccentrically. In addition, the retaining element can have elastic webs, which are arranged distributed relative to each other in the circumferential direction and by means of the corresponding positions in the circumferential direction, the adjustment of the properties of the retaining element can be performed within the desired rigidity plane.

[0021] The bearing arrangement according to the invention can be used to manufacture steering gears for vehicles. However, the invention is not limited to this use. Alternatively, the bearing arrangement according to the invention can be used to produce seat adjustment devices, single-wheel actuation with a wheel rotating about a vertical wheel axis, gear mechanisms of steer-by-wire units, window lift mechanisms, machine tools, etc. An important aspect is that with the bearing arrangement according to the invention the worm is pretensioned against the worm wheel.

[0022] According to an advantageous embodiment, the retaining element and the outer bearing ring form a bayonet closure. The retaining element can thus be permanently and releasably connected to the radial bearing in a simple and secure manner without being damaged. In order to produce the bayonet closure, at least one partially circumferential radially outwardly oriented shoulder can be provided on the outer bearing ring, which shoulder engages behind after the retaining element has been mounted on the outer bearing ring and subsequently rotated relative to the outer bearing ring about the longitudinal center axis of the radial bearing by the radially inwardly directed portion of the retaining element, so as to fix the retaining element to the outer cover surface of the outer bearing ring in an axially non-movable manner. In addition, a further anti-rotation component must be provided, which prevents the retaining element from rotating in an undesirable manner relative to the outer bearing ring or a resulting loosening of the bayonet closure.

[0023] Advantageously, the bearing arrangement has at least one securing ring which engages in a groove which is circumferentially configured in the outer cover surface of the outer bearing ring and is arranged directly adjacent to the retaining element on the side of the retaining element which is arranged facing the worm thread. In a bayonet closure between the retaining element and the outer bearing ring, the securing ring ensures that the retaining element cannot be released from the outer bearing ring in an undesirable manner. The securing ring can also perform the function of the above-mentioned anti-rotation component. The securing ring is made of metal or a metal alloy and can be configured like a piston ring.

[0024] It is further advantageous if an at least partially circumferential chamfer is configured at an axial end of the inner cover surface of the retaining element and / or the fixing ring, which end is arranged facing the worm thread, and at least one chamfer of the same orientation and at least partially circumferential is configured on the outer bearing ring, which matches the chamfer. Due to the contact and radial forces of the chamfer, the retaining element or the fixing ring is axially prestressed away from the worm thread. In this case, the retaining element can be prestressed, for example, against a circumferential shoulder on the outer cover surface of the outer bearing ring. Alternatively or additionally, the fixing ring can be prestressed against the side of the retaining element facing the worm thread.

[0025] Another advantageous embodiment provides that the outer bearing ring is arranged with an outer diameter at the axial end arranged facing the worm thread, which outer diameter is smaller than the outer diameter of the part of the outer bearing ring adjacent to the axial end on the side of the axial end arranged facing away from the worm thread, so that a circumferential shoulder is formed on the outer cover surface of the outer bearing ring, the retaining element is mounted on the axial end of the outer bearing ring and is axially supported on one side on the shoulder, and a circumferential groove is formed in the outer cover surface of the axial end of the outer bearing ring, in which groove a fixing ring is engaged, which fixing ring is arranged directly adjacent to the retaining element on the side of the retaining element arranged facing the worm thread. In this case, the retaining element can be designed, for example, in an annular manner so as to be able to be mounted on the axial end of the outer bearing ring in a rigidly locked manner. The fixing ring ensures that the retaining element cannot be released from the outer bearing ring in an undesirable manner. The fixing ring is made of metal or a metal alloy and can be designed according to a piston ring.

[0026] Advantageously, an at least partially circumferential chamfer is formed at an axial end of the inner cover surface of the retaining ring, which axial end is arranged facing the worm thread, wherein at least one identically oriented at least partially circumferential chamfer cooperating with the chamfer is formed on the axial end of the outer bearing ring. Due to the contact and radial forces of the chamfer, the retaining ring is axially prestressed away from the worm thread. In this case, the retaining ring is prestressed against the side of the retaining element facing the worm thread.

[0027] According to a further advantageous embodiment, at least one circumferential groove is formed on the outer cover surface of the outer bearing ring, in which groove the retaining element engages in a positively locking manner. This constitutes a structurally simple embodiment, in which the axial fixation of the retaining element to the outer cover surface of the outer bearing ring is produced by the positively locking engagement of the retaining element in the groove of the outer cover surface of the outer bearing ring. In this case, the retaining element is not designed as a closed ring. For example, the retaining element can have at least two retaining element parts, which are arranged on the outer bearing ring in a circumferentially offset manner relative to each other, or can be designed in a U-shaped manner.

[0028] The at least partially circumferential chamfer is advantageously formed in the retaining element on the axial end of the cover surface arranged facing the worm thread, wherein at least one identically oriented at least partially circumferential chamfer cooperating with the chamfer is formed in the groove. Due to the contact and radial forces of the chamfer, the retaining element is axially prestressed away from the worm thread. In this case, for example, the retaining element can be prestressed against the side wall of the groove facing the worm thread.

[0029] According to a further advantageous embodiment, the retaining element has at least two retaining element parts which are arranged on the radial bearing in a manner circumferentially offset relative to one another. This simplifies the assembly of the bearing arrangement. The retaining element parts can, for example, be arranged on the radial bearing so as to be uniformly circumferentially offset relative to one another.

[0030] Another advantageous embodiment provides that the retaining element is constructed in a disc-shaped manner and / or is arranged on the radial bearing in an at least partially circumferential manner and / or is made at least partially of spring steel and / or has at least one partially circumferential material recess. The fact that the retaining element is constructed in a disc-shaped manner is to be understood as meaning that the material thickness of the retaining element is relatively small compared to its other dimensions and has a flat main surface. The retaining element can be arranged partially or completely circumferentially on the radial bearing. In particular, the retaining element can be arranged and constructed in such a way that it does not protrude axially beyond the radial bearing. By means of the retaining element made of spring steel, the elastic properties required for the retaining element are present for a long time. By selecting the number, shape and relative arrangement of the material recesses or openings, the elasticity or prestressing properties of the retaining element can be optimally adjusted.

[0031] The above object is further achieved by a steering gear having the features of claim 11 , wherein the bearing arrangement is designed according to any one of the above-described embodiments or at least two of these embodiments in combination with one another.

[0032] The above advantages regarding the bearing device are correspondingly associated with the steering gear. The steering gear according to the present invention is configured as a worm gear. The steering gear according to the present invention can also have a movable bearing, through which the additional end of the worm is supported. In addition, at least one limiting protrusion can be configured on the steering gear housing, and the movable bearing in the steering gear housing is limited by the limiting protrusion.

[0033] According to an advantageous embodiment, at least one shoulder arranged at least partially circumferentially is formed on the steering housing, to which the side of the retaining element facing the worm thread axially adjoins, wherein the outer covering surface of the retaining element tapers conically in the direction of the worm thread, and wherein the circumferential contact surface of the steering housing, which surface contacts the outer covering surface of the retaining element, tapers in the direction of the shoulder in line with the outer covering surface of the retaining element. Due to the conical structure of the outer covering surface of the retaining element and the contact surface of the steering housing, radially inward forces are applied to the retaining element, whereby the retaining element is clamped between the contact surface and the outer bearing ring of the radial bearing. On the side of the contact surface facing away from the worm thread, an internal thread can be formed on the steering housing, into which an additional component with an external thread can be screwed, in order to push the retaining element in the direction of the worm thread or to prestress it against the radially inwardly directed circumferential shoulder, which shoulder defines the contact surface on the side facing the thread on the steering housing.

[0034] According to another advantageous embodiment, the retaining element is constructed in a U-shaped manner and has two components connected to each other and its free end portion is fixed to the steering gear housing. The retaining element can be arranged in the steering gear housing in such a way that the retaining element portion connecting the two components to each other is positioned on the opposite side of the worm wheel relative to the longitudinal center axis of the radial bearing or the worm. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Further advantageous embodiments of the invention are disclosed in the dependent claims and in the following description of the figures. In the figures:

[0036] Figure 1 a is a schematic diagram of a traditional steering gear.

[0037] Figure 1 b is Figure 1 Schematic diagram of a detail of the fixed bearing arrangement shown in a,

[0038] Figure 2 a is a schematic cross-sectional view of an embodiment of a bearing device according to the present invention,

[0039] Figure 2 b is Figure 2 Schematic diagram of the bearing arrangement shown in a,

[0040] Figure 3 is a schematic cross-sectional view of a portion of another embodiment of a bearing device according to the present invention,

[0041] Figure 4 is a schematic cross-sectional view of a portion of another embodiment of a bearing device according to the present invention,

[0042] Figure 5 a is a schematic cross-sectional view of another embodiment of a steering gear according to the present invention,

[0043] Figure 5 b is Figure 5 Schematic diagram of the bearing arrangement shown in a,

[0044] Figure 5 c is Figure 5 a is a schematic cross-sectional view of a detail of the steering gear shown in FIG.

[0045] Figure 6 a is a schematic diagram of another embodiment of a bearing device according to the present invention, and

[0046] Figure 6 b is Figure 6 a is a schematic cross-sectional view of a detail of a bearing arrangement shown. DETAILED DESCRIPTION

[0047] In the different figures, identical components are always provided with the same reference symbols, so that they are also described overall only once.

[0048] Figure 1 a is a schematic diagram of a conventional steering gear 1 used in an electric power steering system (not shown) of a vehicle (not shown). The steering gear 1 is configured as a worm gear.

[0049] The steering gear 1 has a steering gear housing 2, wherein Figure 1 a shows only the stop projection 3 of the steering gear housing 2, the function of which is explained below. In addition, the steering gear 1 has a worm 4, which is arranged in the steering gear housing 2 and is rotatably supported about its longitudinal axis 5. The steering gear 1 also has a worm wheel 6, which meshes with the worm 4 and is rotatably supported via a shaft 7. The rotational movement of the shaft 7 and / or the axis 5 can be detected by a sensor so that the electric power steering system can be controlled accordingly.

[0050] The steering gear 1 has a fixed bearing device 8, by which the worm 4 is rotatably supported on the steering gear housing 2. The fixed bearing device 8 can be constructed according to patent document US 8667 858 B2 and has a radial bearing housing 10, Figure 1 The radial bearing shown in FIG. b is arranged in this radial bearing housing 10. Furthermore, the fixed bearing device 8 has a retaining disk 11 which is partially arranged in the radial bearing housing 10 and by means of which the fixed bearing device 8 is connected to the steering gear housing 2. The worm 4 is prestressed against the worm wheel 6 by means of elastic deformation of the retaining disk 11. In this case, the retaining disk 11 generates a tilting moment on the radial bearing, which is indicated by the arrow 13.

[0051] In addition, the steering gear 1 has a movable bearing 12, on which the worm 4 is further rotatably supported. In order to limit the mobility of the worm 4 away from the worm wheel 6, a stop projection 3 is constructed on the steering gear housing 2, on which the movable bearing 12 can be supported. The tooth separation can cause the movement of the worm 4.

[0052] Figure 1 b is Figure 1 A schematic diagram of a detail of the steering gear 1 shown in a. A retaining disc 11 is shown, which is connected to a radial bearing 14, which is arranged in Figure 1 a is shown in the radial bearing housing 10. The retaining disk 11 has an opening 15, through which the elasticity of the retaining disk 11 is adjusted.

[0053] Figure 2 a is a schematic cross-sectional view of an embodiment of a bearing device 16 according to the present invention, which is used to support a worm (not shown) of a steering gear (not shown) on a steering gear housing (not shown) of the steering gear.

[0054] The bearing arrangement 16 has a radial bearing 17 which is connected to the worm in a rotationally fixed manner and is in the form of a radial roller bearing. The radial bearing 17 has an inner bearing ring 18, an outer bearing ring 19, and rolling elements 20, which are connected to the worm in a play-free manner and are arranged between the inner bearing ring 18 and the outer bearing ring 19.

[0055] Furthermore, the bearing arrangement 16 has an elastically constructed retaining element 21 which connects the radial bearing 17 to the steering gear housing. The retaining element 21 is connected only to the outer cover surface 22 of the outer bearing ring 19 on the radial bearing side. The retaining element 21 is fixed to the outer cover surface 22 of the outer bearing ring 19 in an axially immovable manner relative to the longitudinal center axis 23 of the radial bearing 17.

[0056] The retaining element 21 is disk-shaped and annular. The retaining element 21 is arranged completely circumferentially on the radial bearing 17. The retaining element 21 is made completely of spring steel. The retaining element 21 has two partially circumferential material recesses 24, Figure 2 a shows only one material recess 24. The structure of the retaining element 21 is Figure 2 b. The retaining element 21 and the outer bearing ring 19 form a bayonet closure, the structure of which can be seen together. Figure 2 a and Figure 2 b becomes clearer.

[0057] The outer bearing ring 19 has an axially protruding axial end 25 with a reduced outer diameter, to which the retaining element 21 is fixed in an axially non-displaceable manner. Two radially outwardly oriented partial circumferential shoulders 26 are arranged at the free end of the axial end 25 in a circumferentially offset manner relative to one another, wherein Figure 2 a Only one shoulder 26 is shown.

[0058] Figure 2 b is Figure 2 A schematic diagram of a bearing device 16 is shown in FIG. Two shoulders 26 can be seen which are diametrically opposed to each other with respect to the longitudinal center axis 23 of the radial bearing 17 and between which a partially circumferential recess 27 is formed. It can also be seen that the retaining element 21 has a continuous outer ring 28, two inner ring parts 29, which are arranged in a partially circumferential manner and in line with the shoulders 26 in a circumferentially offset manner relative to each other, and two connecting parts 30, which are integrally connected to the outer ring 28 via two connecting parts 30.

[0059] In order to connect the retaining element 21 to the outer bearing ring 19 or to construct a bayonet closure, the retaining element 21 is arranged relative to the outer bearing ring 19. Figure 2 The position shown in FIG. b is rotated 90° about the longitudinal center axis 23 of the radial bearing 17 so that the inner ring portion 29 can be axially guided through the recess 27 between the shoulders 26. Subsequently, the retaining element 21 is moved axially relative to the outer bearing ring 19 until the inner ring portion 29 has passed the shoulders 26. Subsequently, the retaining element 21 is rotated about the longitudinal center axis 23 of the radial bearing 17 by approximately 90° to Figure 2 b. In addition, the retaining element 21 is fixed relative to the outer bearing ring 19 by means of an anti-rotation component. Figure 2 b, the anti-rotation member, not shown, resists rotation about the longitudinal center axis 23 of the radial bearing 17.

[0060] Figure 3 is a schematic cross-sectional view of a portion of a bearing device 31 according to another embodiment of the present invention, the bearing device 31 being used to support a worm (not shown) of a steering gear (not shown) on a steering gear housing (not shown) of the steering gear.

[0061] The bearing device 31 and Figure 2 a and Figure 2 The embodiment shown in FIG. 2 differs essentially in that it also has a fixing ring 32 which engages in a groove 35 which is formed circumferentially in the outer cover surface 22 of the outer bearing ring 33 of the radial bearing 34 and is arranged on the side of the retaining element 21 which is arranged facing the worm thread (not shown), i.e. on the side of the retaining element 21 which is arranged facing the worm thread (not shown). Figure 3The right side of the retaining element 21 in the middle) is directly adjacent to the retaining element 21, wherein the retaining element 21 is engaged in the same groove 35. The groove 35 has a deeper part 36 away from the thread and engaged with the retaining element 21 and a part 37 close to the thread and having a smaller depth and in which the fixing ring 32 is engaged.

[0062] At the axial end of the inner cover surface 38 of the fixing ring 32, which end is arranged facing the worm thread, an at least partially circumferential chamfer 39 is formed. An at least partially circumferential chamfer 40 cooperating with the chamfer 39 is formed on the outer bearing ring 33 or the groove 35. The fixing ring 32 is elastically deformed in the position shown in such a way that a restoring force is generated therein, by which the fixing ring 32 is radially pressed against the chamfer 40 and is thereby axially prestressed in the direction of the retaining element 21 or against the retaining element 21.

[0063] Figure 4 is a schematic cross-sectional view of a portion of a bearing device 41 according to another embodiment of the present invention, the bearing device 41 being used to support a worm (not shown) of a steering gear (not shown) on a steering gear housing (not shown) of the steering gear.

[0064] The bearing device 41 and Figure 2 a and Figure 2 The embodiment shown in FIG. 2 differs primarily in that the retaining element 21 and the outer bearing ring 42 of the radial bearing 43 do not form a bayonet closure, the retaining element 21 has an inner ring portion which is arranged completely circumferentially on the outer bearing ring 42 and is not shown in detail, and in that the outer bearing ring 42 has an outer diameter at an axially protruding axial end 44 arranged facing the worm thread (not shown) which is smaller than the outer diameter of a portion 46 of the outer bearing ring 42 which is arranged adjacent to the axial end 44 on the side facing away from the worm thread, and a peripheral shoulder 45 is formed on the outer cover surface 22 of the outer bearing ring 42. The retaining element 21 is mounted on the axial end 44 of the outer bearing ring 42 and is axially supported on one side on the shoulder 45.

[0065] A circumferential groove 47 is formed in the outer cover surface of the axial end 44 of the outer bearing ring 42, in which groove a fixing ring 32 engages, which fixing ring 32 is arranged on the side of the retaining element 21 facing the worm thread (i.e. on the side of the retaining element 21 facing the worm thread). Figure 4The outer bearing ring 42 is provided with a chamfer 39 which is arranged on the right side of the retaining element 21 in the retaining ring 32 and is arranged directly adjacent to the retaining element 21. An at least partially circumferential chamfer 39 is formed at the axial end of the cover surface 38 arranged to face the worm thread in the retaining ring 32. An at least partially circumferential chamfer 40 which is oriented in the same direction and cooperates with the chamfer 39 is formed on the axial end 44 of the outer bearing ring 42. In the position shown, the retaining ring 32 is elastically deformed in such a way that a restoring force is generated, by which the retaining ring 32 is radially pressed against the chamfer 40 and is thereby axially prestressed in the direction of the retaining element 21 or against the retaining element 21. The outer diameter of the retaining ring 32 is greater than the inner diameter of the retaining element 21.

[0066] Figure 5 a is a schematic cross-sectional view of another embodiment of a steering gear 48 for an electric power steering system (not shown) of a vehicle not shown according to the present invention. The steering gear 48 is configured as a worm gear.

[0067] The steering gear 48 has a steering gear housing 49, wherein Figure 5 Only the bearing projection 50 is shown, the function of which is explained below. In addition, the steering gear 48 has a worm (not shown), which is arranged in the steering gear housing 49 and is rotatably supported about its longitudinal axis (not shown). The steering gear 48 also has a worm wheel 6 (not shown), which meshes with the worm and is rotatably supported via a shaft. The rotational movement of the shaft can be detected by a sensor so that the electric power steering system can be controlled accordingly.

[0068] The steering gear 48 has a bearing device 51, and the worm is rotatably supported on the steering gear housing 49 by the bearing device 51. In addition, the steering gear 48 may have a movable bearing (not shown), and the worm is further rotatably supported on the bearing. In order to limit the mobility of the worm away from the worm wheel, a stopper protrusion (not shown) may be constructed on the steering gear housing 49, and the movable bearing may be supported thereon. The steering gear 48 may be configured according to Figure 1 a is constructed with respect to the movable bearing.

[0069] The bearing device 51 and Figure 4 The embodiment shown differs in that a circumferential groove 54 is formed in the outer cover surface 22 of the outer bearing ring 52 or in the axial end 44 of the outer bearing ring 52 of the radial bearing 53, in which groove 54 only one retaining element 55 engages in a positively locking manner. An at least partially circumferential chamfer 39 is configured at the axial end of the inner cover surface 38 of the retaining element 55 arranged to face the worm thread (not shown). An at least partially circumferential chamfer 40 of the same orientation is configured on the groove 54 and cooperates with the chamfer 39.

[0070] In addition, the bearing device 51 and Figure 4The embodiment shown differs essentially in that the retaining element 55 has two retaining element parts 56 which are arranged on the radial bearing 53 in a circumferentially offset manner relative to one another and in which Figure 5 a shows only one holding element portion 56. The complete structure of the holding element 55 is shown in Figure 5 Shown in b.

[0071] A shoulder 57 is formed on the steering housing 49 or the bearing projection 50, which is arranged in an at least partially circumferential manner and axially adjoins the side of the retaining element 55 or the retaining element part 56 that faces the worm thread (not shown). The outer cover surface 58 of the retaining element 55 or the retaining element part 56 tapers conically in the direction of the worm thread. The outer peripheral contact surface 59 of the steering housing 49 or the bearing projection 50 that contacts the outer cover surface 58 of the retaining element 55 or the retaining element part 56 tapers in the direction of the shoulder 57 in accordance with the outer cover surface 58 of the retaining element 55 or the retaining element part 56. On the side of the contact surface 59 facing away from the worm thread, a surface with a circumferential internal thread 60 adjoins here, so that a component with an external thread (not shown) can be screwed into the steering housing 49, whereby the retaining element 55 or the retaining element part 56 is prestressed relative to the shoulder 57. In this case, the retaining element part 56 is prestressed radially inwardly against the radial bearing 53 by the contact between the outer cover surface 58 and the contact surface 59 of the retaining element part 56. These features of the steering gear 48 are Figure 5 It becomes clearer in c.

[0072] Figure 5 b is Figure 5 Schematic diagram of the bearing device 51 shown in FIG. 2 shows two retaining element parts 56 having the same structure. In particular, each retaining element part 56 has an inner ring part 61, an outer ring part 62 and a connecting part 63, wherein the inner ring part 61 is engaged with the outer ring part 62 and the connecting part 63. Figure 5 In the groove in the outer bearing ring 52 or the axial end 44 of the outer bearing ring 52 shown in FIG. a, the outer ring portion 62 is arranged radially outside and spaced apart from the inner ring portion 61, and the connecting portion 63 connects the inner ring portion 61 to the outer ring portion 62. The corresponding inner ring portion 61 extends at a larger angle than the corresponding outer ring portion 62.

[0073] Figure 5 c is Figure 5 A schematic sectional view of a detail of the steering gear 48 in the region of the bearing projection 50 of the steering gear housing 49. The tapering of the outer cover surface 58 of the retaining element part 56 in the same orientation as the contact surface 59 of the bearing projection 50 can be seen.

[0074] Figure 6a is a schematic diagram of a bearing device 64 according to another embodiment of the present invention, wherein the bearing device 64 is used to support a worm (not shown) of a steering gear (not shown) on a steering gear housing (not shown) of the steering gear.

[0075] The bearing arrangement 64 has a radial bearing 65 which is connected to the worm in a rotationally fixed manner and is in the form of a radial roller bearing. The radial bearing 65 has an inner bearing ring 18, an outer bearing ring 66, which is connected to the worm in a play-free manner, and rolling elements (not shown) which are arranged between the inner bearing ring 18 and the outer bearing ring 66.

[0076] Furthermore, the bearing arrangement 64 has an elastically designed retaining element 67, which connects the radial bearing 65 to the steering gear housing. The retaining element 67 is connected only to the radial bearing side, such as Figure 6 b shows the outer cover surface of the outer bearing ring 66. The retaining element 67 is fixed to the outer cover surface of the outer bearing ring 66 in an axially immovable manner relative to the longitudinal center axis 23 of the radial bearing 65. Figure 6 The structure of the outer bearing ring 66 is better understood in b.

[0077] The retaining element 67 is designed in a disk-like manner. The retaining element 21 is arranged in a partially circumferential manner on the radial bearing 65. The retaining element 67 is made completely of spring steel. The retaining element 67 has a partially circumferential material recess 24. The retaining element 67 is designed in a U-shaped manner and has two interconnected components 68, the free end sections of which can be fixed to a fixing point 69 on the steering housing.

[0078] Figure 6 b is Figure 6 A schematic sectional view of a detail of a bearing device 64 is shown in FIG. A circumferential groove 70 is formed in the outer cover surface 22 of the outer bearing ring 66, in which the retaining element 67 engages in a positively locked manner. In particular, the groove 70 is arranged on the axial end 9 of the outer bearing ring 66, which protrudes axially in the direction of the thread (not shown) of the worm.

[0079] List of reference numerals:

[0080] 1 Steering gear

[0081] 2 Steering gear housing

[0082] 3 Limiting protrusion

[0083] 4 Worm

[0084] 5 4 longitudinal center axis

[0085] 6 Worm gear

[0086] 7 Axis

[0087] 8 Fixed bearing assembly

[0088] 9 66 Axial end

[0089] 10 Radial bearing housing

[0090] 11. Keep the disk

[0091] 12 Movable bearing

[0092] 13 Arrow (tilting moment)

[0093] 14 Radial bearings

[0094] 15 11 openings

[0095] 16 Bearing assembly

[0096] 17 Radial bearings

[0097] 18 Inner bearing ring

[0098] 19 Outer bearing ring

[0099] 20 Rolling element

[0100] 21. Retaining element

[0101] 22 19, 33, 42, 52, 66 outer coverage

[0102] 23 17 longitudinal center axis

[0103] 24 Material notches at 21 and 67

[0104] 25 19 Axial end portion

[0105] Shoulder at 26 and 25

[0106] 27 Notch at 25

[0107] 28 21 outer ring

[0108] 29 21 inner ring

[0109] 30 21 connection part

[0110] 31 Bearing assembly

[0111] 32 Fixing ring

[0112] 33 Outer bearing ring

[0113] 34 Radial bearings

[0114] 35 33 grooves

[0115] 36 35 Part away from the thread

[0116] 37 35 Part close to the thread

[0117] 38 32 inner coverage

[0118] Chamfer at 39 38

[0119] Chamfer at 40 35

[0120] 41 Bearing device

[0121] 42 Outer bearing ring

[0122] 43 Radial bearings

[0123] 44 42, 52, 66 axial end

[0124] Shoulders at 45-42

[0125] 46 42 parts

[0126] Grooves at 47 and 44

[0127] 48 Steering gear

[0128] 49 Steering gear housing

[0129] 50 Bearing protrusion

[0130] 51 Bearing device

[0131] 52 Outer bearing ring

[0132] 53 Radial bearings

[0133] 54 52 grooves

[0134] 55 Holding element

[0135] 56 Holding element part

[0136] 57 50 shoulder

[0137] 58 55, 56 outer coverage

[0138] 59 50 contact surface

[0139] 60 Internal thread

[0140] The inner ring of 61 56

[0141] Outer ring of 62 56

[0142] 63 56 connection part

[0143] 64 Bearing assembly

[0144] 65 Radial bearing

[0145] 66 Outer bearing ring

[0146] 67 Holding element

[0147] 68 67 components

[0148] Fixed position at 69 and 68

[0149] Grooves at 70 66

Claims

1. A bearing arrangement for supporting a worm of a steering gear on a steering gear housing of the steering gear, the bearing arrangement comprising at least one radial bearing connected to the worm in a rotationally fixed manner and at least one retaining element which connects the radial bearing to the steering gear housing and is of elastic construction, It is characterized in that The retaining element is connected on the radial bearing side only to the outer cover surface of the outer bearing ring of the radial bearing, and The radial bearing has two shoulders which are diametrically opposed to each other relative to the longitudinal center axis, and a partially circumferential recess is configured between the shoulders. The retaining element is rotated about the longitudinal center axis of the radial bearing so that the retaining element is axially guided through the recess between the shoulders, so that the retaining element is fixed to the outer cover surface of the outer bearing ring in a manner that the retaining element cannot be axially moved relative to the longitudinal center axis of the radial bearing.

2. The bearing device according to claim 1, It is characterized in that The retaining element and the outer bearing ring form a bayonet closure, wherein the retaining element has a continuous outer ring, two inner ring parts, and two connecting parts, which are arranged in a partially circumferential manner and are arranged in a circumferentially offset manner relative to each other in line with the shoulder, and the inner ring part is integrally connected to the outer ring via two connecting parts.

3. The bearing device according to claim 2, It is characterized in that The device has at least one securing ring which engages in a groove which is formed circumferentially in the outer cover surface of the outer bearing ring and is arranged directly adjacent to the retaining element on that side of the retaining element which is arranged facing the thread of the worm.

4. The bearing device according to claim 3, It is characterized in that An at least partially circumferential chamfer is configured at an axial end of the inner cover surface of the retaining element and / or the fixing ring, the axial end being arranged to face the thread of the worm, and at least one identically oriented and at least partially circumferential chamfer cooperating with the chamfer is configured on the outer bearing ring.

5. The bearing device according to claim 1, It is characterized in that the outer bearing ring having, at an axial end arranged facing the thread of the worm, a smaller outer diameter than an outer diameter of a portion of the outer bearing ring which adjoins the axial end on a side of the axial end arranged facing away from the thread of the worm, so that an outer peripheral shoulder is formed on the outer cover surface of the outer bearing ring, The retaining element is mounted on the axial end of the outer bearing ring and is axially supported on one side on the shoulder, and A circumferential groove is formed in the outer cover surface of the axial end of the outer bearing ring, in which groove a securing ring engages, which is arranged directly adjacent to the retaining element on the side of the retaining element arranged facing the thread of the worm.

6. The bearing device according to claim 5, It is characterized in that An at least partially circumferential chamfer is configured at an axial end of the inner cover surface of the fixing ring, the axial end being arranged to face the thread of the worm, and at least one at least partially circumferential chamfer of the same orientation cooperating with the chamfer is configured on the axial end of the outer bearing ring.

7. The bearing device according to claim 1, It is characterized in that An at least partially circumferential chamfer is formed on an axial end of the inner cover surface of the retaining element, which axial end is arranged facing the thread of the worm.

8. The bearing device according to claim 1, It is characterized in that The retaining element has at least two retaining element parts which are arranged on the radial bearing in a circumferentially offset manner relative to one another.

9. Bearing device according to one of the preceding claims, It is characterized in that The retaining element is designed in a disk-shaped manner and / or is arranged at least partially circumferentially on the radial bearing and / or is at least partially made of spring steel and / or has at least one partially circumferential material recess.

10. A steering gear for an electric power steering system of a vehicle, the steering gear comprising a steering gear housing, a worm arranged in the steering gear housing, and at least one bearing device, wherein the worm is rotatably supported on the steering gear housing by the bearing device, It is characterized in that The bearing arrangement is designed according to one of the preceding claims.

11. The steering gear according to claim 10, It is characterized in that At least one at least partially circumferentially arranged shoulder is constructed on the steering gear housing, and the side of the retaining element facing the thread of the worm is axially adjacent to the shoulder, the outer covering surface of the retaining element gradually tapers conically in the direction of the worm thread, and the circumferential contact surface of the steering gear housing that contacts the outer covering surface of the retaining element gradually tapers in the direction of the shoulder in accordance with the outer covering surface of the retaining element.

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