Bearing arrangement for a vehicle steering device and vehicle steering device comprising this

Abstract

A bearing arrangement for a vehicle steering device is disclosed here, comprising a bearing having an inner ring attached to a rack rod, an outer ring arranged outside the inner ring with a ball inserted between them, a sealing element provided between the inner ring and the outer ring, and an elastic clamp comprising a body pressed against an outer peripheral surface of the outer ring, fastening sections bent in a direction towards the sides of the outer ring extending from both ends of the body, and elastic sections extending from respective ends of the fastening sections and projecting laterally from the outer ring such that they each have a curvature.

Description

Field of the invention

[0001] Exemplary embodiments of the present invention relate to a vehicle steering apparatus and, more particularly, to a bearing assembly provided in a vehicle steering apparatus. Description of the state of the art

[0002] In recent years, electric power steering devices using electric motors have gradually been widely derived from hydraulic power steering devices using hydraulic pressure from hydraulic pumps as power steering devices for vehicles.

[0003] Such a typical electric power steering device includes a steering device that connects a steering wheel to both wheels and an auxiliary power device that supplies an auxiliary steering force to the steering device.

[0004] The power assist device includes a torque sensor that detects a steering torque applied by a driver to a steering wheel and outputs an electrical signal proportional to the detected steering torque, an ECU (Electronic Control Unit) that generates a control signal in response to the electrical signal transmitted from the torque sensor, a motor (electric motor) that generates a steering assist force in response to the control signal transmitted from the ECU, and a belt transmission that transmits the steering assist force generated by the motor to a rack bar through a belt.

[0005] Fig. 1 is a perspective view illustrating a conventional vehicle steering apparatus. Fig. 2 is a perspective view illustrating an interior of a rack housing of the conventional vehicle steering apparatus.

[0006] With reference to Fig. 1, the conventional vehicle steering apparatus includes a pinion shaft 10 connected to a steering wheel (not shown) to rotate along with the rotation of the steering wheel, a ball screw type rack bar 30 that is linearly moved by the rotational force of the pinion shaft 10, and a drive unit 50 that provides an auxiliary force for the linear movement of the rack bar 30.

[0007] The rack bar 30 is rotatably housed in a rack housing 40, and connecting units or coupling or joint units 60 are connected to both sides of the rack bar 30. The rack housing 40 may be provided with a mounting bracket 70 that secures the rack housing to a vehicle body.

[0008] With reference to Fig. 2, the drive unit 50 includes an electric motor controlled by an ECU, a drive pulley fixed to the shaft of the electric motor, and an intermeshing pulley 51 coupled to the outer side of the rack bar so as to rotatably mesh with the drive pulley.

[0009] The drive pulley and the toothed pulley are arranged axially parallel to each other. When electrical power is applied to the electric motor, the rotational force of the electric motor is transmitted to the rack bar 30, so that the rack bar 30, which has rack teeth 31, slides in the left and right directions through the operation of a ball nut 20, thereby obtaining the assist force required for steering.

[0010] The ball nut 20 is a hollow tube coupled to the outer peripheral surface of the rack bar 30, and has stepped jaws formed on both sides of the outer peripheral surface thereof. The toothed pulley 51 is installed on one axial side of the ball nut 20 so as to be pressed against the associated one of the stepped jaws, and a lock nut (not shown) fixedly coupled to the ball nut 20 is installed on one side of the toothed pulley 51 to fix the toothed pulley 51 to the rack bar 30.

[0011] A bearing 80 is installed on the other axial side of the ball nut 20 to be pressed against the associated one of the stepped jaws, and the bearing 80 is fixed by a lock nut coupled to the other end of the ball nut 20.

[0012] In this case, shaft washers 81 are coupled to both sides of the bearing 80 to provide axial and elastic support for the bearing 80. Conventional assembly of the shaft washers 81 to the bearing 80 requires a relatively long time, and it is necessary to manufacture new shaft washers to increase the spring force of the shaft washers 81 coupled to the bearing 80. Consequently, the manufacturing and assembly time of the bearing may be longer. [Prior art document][Patent document]

[0013] (Patent Document 1) Korean Patent Application Publication No. 10-2006-0101622

[0014] DE 10 2010 002 958 A1 describes a power steering system, in particular an electric power steering system for a vehicle, comprising a rotating component driven by a servomotor and a rolling bearing for axially and radially supporting the component in the frame. To reduce operating noise and friction within the power steering system, at least one inner ring or one outer ring of the rolling bearing is divided into two ring parts along a parting plane running approximately perpendicular to a longitudinal axis of the rotating component, which ring parts are axially spring-loaded against one another.

[0015] DE 10 2009 016 187 A1 describes a device for generating a pivoting moment on a pivotably mounted shaft, wherein the shaft is rotatable about its axially extending axis of rotation in a housing by means of a bearing and is pivotally mounted relative to the housing about a pivot point lying on the axis of rotation, wherein the device has at least one spring element which is resiliently prestressed against the shaft at a distance from the pivot point.

[0016] DE 18 98 688 U describes a means of securing a ring arranged in a bore against rotation by means of a clamp which is placed under tension in the radial direction on the ring and whose part projecting beyond the periphery of the ring is received in a groove in the bore parallel to the axis.

[0017] WO 2015 / 029672 A1 describes a power steering device, wherein a space between a housing and a rotary shaft includes a chamber, which is a space located axially closer to one side than a bearing supporting a nut and a plurality of balls in the nut, and another chamber, which is a space located closer to the other side. A communication hole, which establishes communication between one and the other chamber, is arranged in a portion of the nut, excluding a portion where the plurality of balls orbit on a nut-side ball screw groove, or in a member arranged radially outside the nut and radially inside an inner wall of the housing. OVERVIEW OF THE INVENTION

[0018] An object of the present invention is to provide a bearing assembly for a vehicle steering device that can easily adjust a spring force to elastically support a bearing.

[0019] Further objects and advantages of the present invention can be understood from the following description and will become apparent upon reference to the embodiments of the present invention. It will also be apparent to those skilled in the art to which the present invention belongs that the objects and advantages of the present invention can be realized by the means claimed and combinations thereof.

[0020] In accordance with the present invention, there is provided a bearing assembly for a vehicle steering device having the features of claim 1, a bearing assembly for a vehicle steering device having the features of claim 7, and a vehicle steering device having the features of claim 14.

[0021] Advantageous further training results from the dependent subclaims.

[0022] It should be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects, features and other advantages of the present invention will become more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: Fig. 1 is a perspective view illustrating a conventional vehicle steering apparatus; Fig. 2 is a perspective view illustrating an interior of a rack housing of the conventional vehicle steering apparatus; Fig. 3 is a perspective view illustrating a bearing assembly for a vehicle steering apparatus in accordance with a first embodiment of the present invention coupled to a rack bar of a vehicle steering apparatus; Fig. 4 is an exploded perspective view illustrating the bearing assembly for a vehicle steering apparatus in accordance with the first embodiment of the present invention; Fig. 5 is an exploded perspective view illustrating a bearing assembly for a vehicle steering apparatus in accordance with a second embodiment of the present invention; Fig. 6 is an exploded perspective view illustrating a bearing assembly for a vehicle steering apparatus in accordance with a third embodiment of the present invention; and Fig. 7 is an exploded perspective view illustrating a bearing assembly for a vehicle steering apparatus in accordance with a fourth embodiment of the present invention. DESCRIPTION OF SPECIFIC EMBODIMENTS

[0024] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. The present invention may, however, be embodied in different forms and should not be considered limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. Throughout the disclosure, like reference characters refer to like parts throughout the various figures and embodiments of the present invention.

[0025] It will be understood that, whenever an element is referred to as being "connected" to another element throughout the specification, that element may be "directly" "connected" to the other element, or it may be "electrically" "connected" to the other element, with other elements interposed therebetween. Furthermore, it will be understood that whenever a component or part is referred to as "comprising" any component or part, this does not exclude other components or parts, but may further comprise the other components or parts, unless otherwise specified.

[0026] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0027] A vehicle steering device using a bearing assembly in accordance with exemplary embodiments of the present invention includes a steering wheel, a pinion shaft connected to the steering wheel to rotate along with the rotation of the steering wheel, a rack bar that is linearly moved by the rotational force of the pinion shaft, a ball nut coupled to the outer side of the rack bar, and a drive unit that provides an auxiliary power for the linear movement of the rack bar. Since these components are similar to those of the conventional steering device used in Fig. 1 and Fig. 2, a detailed description thereof will be omitted.

[0028] Fig. 3 is a perspective view illustrating a bearing assembly for a vehicle steering apparatus in accordance with a first embodiment of the present invention. Fig. 4 is an exploded perspective view illustrating the bearing assembly for a vehicle steering apparatus in accordance with the first embodiment of the present invention.

[0029] With reference to Fig. 3 and Fig. 4, the bearing assembly, designated by reference numeral 100, in accordance with the first embodiment comprises a bearing 110 which supports the rotation of a ball nut 20 (see Fig. 1), and an elastic clamp 120 which is coupled to the bearing 110.

[0030] The bearing 110 is fixed to the outer side of the ball nut 20, which is coupled to the outer peripheral surface of a rack rod 30, and includes an inner ring 111 coupled to the outer side of the ball nut, an outer ring 112 disposed outside the inner ring 111 at a distance therefrom, a ball (not shown) inserted between the inner ring 111 and the outer ring 112, and a sealing member 113 provided between the inner ring 111 and the outer ring 112 to prevent the removal of the ball and the introduction of foreign matter.

[0031] The outer ring 112 may have a greater width than the sealing member 113 so that the elastic clamp 120 can be stably attached to the outer ring 112.

[0032] The sealing member 113 may be made of a material capable of sufficiently sealing a gap between the inner ring 111 and the outer ring 112, for example, rubber, and may be formed between the inner ring 111 and the outer ring 112 by insert injection molding.

[0033] The elastic clamp 120 may consist of a plurality of elastic clamps coupled to the outer side of the outer ring 112, and the plurality of elastic clamps 120 may be arranged at regular intervals or at irregular intervals. Each of the elastic clamps 120 includes a body 121, fastening portions 122 bent from the ends of the body 121, elastic portions 123 extending from the respective ends of the fastening portions 122, and support portions 124 extending from the respective ends of the elastic portions 123. The fastening portions 122, the elastic portions 123, and the support portions 124 may be formed symmetrically on both sides of the body 121.

[0034] Although the body 121 has a substantially flat shape, it may have a curvature that matches the curvature of the outer ring 112 so as to be pressed against the outer peripheral surface of the outer ring 112.

[0035] The attachment portions 122 are bent toward the sides of the outer ring 112 from the ends of the body 121, so that the elastic clamp 120 is attached to the bearing. Each of the attachment portions 122 can extend to a portion of the associated side of the outer ring 112.

[0036] The elastic portions 123 may extend from the ends of the mounting portions 122 and may protrude laterally from the bearing 110 to have a substantially "C"-shaped cross section. Accordingly, a space is defined between the outer ring 112 and each of the elastic portions 123, and the elastic portions 123 can sufficiently provide a spring force in the axial direction of the rack bar in a state where they are stably supported by the outer ring 112.

[0037] The support portions 124 may extend from the ends of the elastic portions 123 so as to rest on the boundary between the outer ring 122 and the sealing member 123. In this case, since the width of the outer ring 122 is greater than the width of the sealing member 123, the support portions 124 can be securely attached to the outer ring 122.

[0038] The bearing assembly having the above configuration can be modularized by simply attaching the elastic clamps 120 to the bearing. Therefore, the overall assembly time of the vehicle steering device can be reduced. Furthermore, the number of elastic clamps attached to the outer side of the bearing 110 can be increased or decreased, and the arrangement of the elastic clamps can be freely adjusted. Therefore, it is possible to freely adjust the overall strength of the bearing assembly.

[0039] Fig. 5 is an exploded perspective view illustrating a bearing assembly for a vehicle steering apparatus in accordance with a second embodiment of the present invention.

[0040] When the elastic clamp 120 is attached to the outer ring 112 of the bearing 110, the elastic clamp 120 protrudes radially from the outer ring 122 by a predetermined amount, so that in this case, a gap is formed between the inner surface of the rack housing and the outer ring 112.

[0041] With reference to Fig. 5, an outer ring 112 of a bearing 110 according to the second embodiment has receiving grooves 112a formed on the outer peripheral surface thereof so that elastic clips 120 are fitted onto the receiving grooves 112a. Bodies 121 of the elastic clips 120 are fitted onto and coupled to the receiving grooves 112, and thus the elastic clips 120 do not protrude radially from the bearing 110. That is, there is no stepped portion between the elastic clips 120 and the outer ring 112. As a result, when the bearing 110 is installed in the rack housing, the outer ring 112 and the elastic clips 120 can be pressed against the inner surface of the rack housing without a gap between them.

[0042] In addition, each of the elastic clamps 120 further includes an elastic reinforcement member 125 formed on the outer side thereof and made of rubber or the like, thereby increasing a spring force. The elastic reinforcement member 125 may be formed integrally with the elastic clamp 120 by insert molding or the like. The elastic reinforcement member 125 may be formed on the entire outer side of the elastic clamp 120 or on a part of the outer side of the elastic clamp 120.

[0043] Fig. 6 is an exploded perspective view illustrating a bearing assembly for a vehicle steering apparatus in accordance with a third embodiment of the present invention.

[0044] With reference to Fig. 6, the bearing assembly in accordance with the third embodiment includes a bearing 110 coupled to a ball nut and an elastic clamp 130 coupled to the bearing 110.

[0045] The bearing 110 includes an inner ring 111 coupled to the outer side of the ball nut, an outer ring 112 disposed outside the inner ring 111 at a distance therefrom, a ball provided between the inner ring 111 and the outer ring 112, and a sealing member 113 provided between the inner ring 111 and the outer ring 112 to prevent the removal of the ball and the introduction of foreign matter.

[0046] The elastic clamp 130 may consist of a plurality of elastic clamps coupled to the outer side of the outer ring 112, and the plurality of elastic clamps 130 may be arranged at regular intervals or at irregular intervals. Each of the elastic clamps 130 includes a body 131, first bent portions 132 bent from the ends of the body 131, second bent portions 133 extending from the respective ends of the first bent portions 132, and elastic portions 134 extending toward the bearing 110 from the respective ends of the second bent portions 133. The first bent portions 132, the second bent portions 133, and the elastic portions 134 may be formed symmetrically on both sides of the body 131.

[0047] The body 131 has a curvature matching the curvature of the outer ring 112 so as to be pressed against the outer peripheral surface of the outer ring 112, and it may have an opening portion 131a formed in the center thereof in the width direction of the outer ring 112 to reduce the overall weight thereof.

[0048] The first bent portions 132 each have a substantially flat shape, and are bent toward the sides of the outer ring 112 from the ends of the body 131 so as to extend to the boundary between the outer ring 112 and the sealing member 113. Therefore, it is possible to further increase the fastening force between the bearing 110 and the elastic clamp 130 compared to the first embodiment.

[0049] The second bent portions 133 may be bent outward from the bearing 110 from the ends of the first bent portions 132, and they may be perpendicular to the first bent portions 132 so that the elastic portions 134 have a sufficient spring force.

[0050] The elastic portions 134 may extend laterally from the bearing 110 from the ends of the second bent portions 133 so as to each have a predetermined curvature, and they may have a substantially "C"-shaped cross section. Accordingly, the elastic portions 134 protrude outward from the outer ring 112 so as to define spaces between the respective elastic portions 134 and the respective first bent portions 132, thereby providing sufficient axial spring force.

[0051] Furthermore, according to the second embodiment, the elastic bracket 130 further includes edge portions 135 extending from the respective ends of the elastic portions 134 and bent outward from the bearing 110 to each have a predetermined curvature. Thus, it is possible to further increase the axial spring force.

[0052] Fig. 7 is an exploded perspective view illustrating a bearing assembly for a vehicle steering apparatus in accordance with a fourth embodiment of the present invention.

[0053] With reference to Fig.7, an outer ring 112 of a bearing 110 according to the fourth embodiment has receiving grooves 112a formed on the outer peripheral surface thereof, so that elastic clips 130 are fitted onto the receiving grooves 112a. Bodies 131 of the elastic clips 130 are fitted onto and coupled to the receiving grooves 112a, and thus there is no stepped portion between the elastic clips 130 and the outer ring 112. Thus, when the bearing 110 is installed in the rack housing, the outer ring 112 and the elastic clips 130 can be pressed against the inner surface of the rack housing without a gap between them.

[0054] As is apparent from the above description, in accordance with exemplary embodiments of the present invention, a bearing assembly can be modularized by simply attaching elastic clamps to a bearing. Therefore, the overall assembly process of a vehicle steering device can be simplified. Furthermore, the number of elastic clamps attached to the outer side of the bearing can be easily increased or decreased, and therefore, it is possible to easily adjust the overall strength of the bearing assembly.

[0055] It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the inventions. Accordingly, the present invention is intended to cover the modifications and variations of the present invention provided they come within the scope of the appended claims and their equivalents.

[0056] Although the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. The exemplary embodiments are to be considered in a descriptive sense only and not for purposes of limitation. Therefore, the scope of the invention is defined not by the detailed description of the invention, but by the appended claims, and all differences within the scope are to be construed as included within the present invention.

Claims

[1] A bearing assembly (100) for a vehicle steering device, the bearing assembly (100) being fixed to an outer side of a ball nut (20) coupled to an outer peripheral surface of a rack rod, the bearing assembly (100) comprising: a bearing (110) comprising an inner ring (111) fixed to the outer side of the ball nut (20), an outer ring (112) arranged outside the inner ring (111), with a ball inserted between them, and a sealing element (113) provided between the inner ring (111) and the outer ring (112); and an elastic clamp (120) having a body (121) pressed against an outer peripheral surface of the outer ring (112), fixing portions (122) bent toward the outer ring (112) sides from both ends of the body (121), and elastic portions (123), which extend from respective ends of the fastening sections (122) and project laterally from the outer ring (112) so that they each have a curvature; wherein the elastic bracket (120) further comprises an elastic reinforcing member (125) formed on an outer side thereof. [2] The bearing assembly (100) of claim 1, wherein the body (121) has a curvature that matches a curvature of the outer ring (112) to be pressed against the outer peripheral surface of the outer ring (112). [3] A bearing assembly (100) according to claim 1, wherein spaces are defined between the respective elastic portions (123) and the respective sides of the outer ring (112). [4] The bearing assembly (100) of claim 1, wherein each of the elastic portions (123) has a substantially "C"-shaped cross section. [5] The bearing assembly (100) of claim 1, wherein the elastic bracket (120) further comprises support portions (124) extending from respective ends of the elastic portions (123), the support portions (124) resting on a boundary between the outer ring (112) and the sealing member (113). [6] The bearing assembly (100) according to claim 1, wherein the outer ring (112) has a receiving groove (112a) formed on the outer peripheral surface thereof so that the elastic bracket (120) is fitted on the receiving groove (112a). [7] A bearing assembly (100) for a vehicle steering device, the bearing assembly (100) being fixed to an outer side of a ball nut (20) coupled to an outer peripheral surface of a rack bar, the bearing assembly (100) comprising: a bearing (110) comprising an inner ring (111) fixed to the outer side of the ball nut (20), an outer ring (112) arranged outside the inner ring (111), with a ball inserted between them, and a sealing element (113) provided between the inner ring (111) and the outer ring (112); and an elastic clamp (130) having a body (131) pressed against an outer peripheral surface of the outer ring (112), first bent portions (132) bent from both ends of the body (131) to a boundary between the outer ring (112) and the sealing member (113), second bent portions (133) bent laterally from the outer ring (112) from respective ends of the first bent portions (132), and elastic portions (134) extending from the respective second bent portions (133) and projecting laterally from the outer ring (112) so as to each have a curvature. [8] The bearing assembly (100) of claim 7, wherein the body (121) has a curvature that matches a curvature of the outer ring (112) to be pressed against the outer peripheral surface of the outer ring (112). [9] The bearing assembly (100) according to claim 7, wherein the body (121) has an opening portion formed in a width direction of the outer ring (112). [10] The bearing assembly (100) of claim 7, wherein spaces are defined between the respective first bent portions (132) and the respective elastic portions (134). [11] The bearing assembly (100) of claim 7, wherein each of the elastic portions (134) has a substantially "C"-shaped cross-section. [12] The bearing assembly (100) of claim 7, wherein the elastic bracket (120) further comprises edge portions (135) extending from respective ends of the elastic portions (134) and projecting outwardly from the bearing (110) to each have a curvature. [13] The bearing assembly (100) according to claim 7, wherein the outer ring (112) has a receiving groove formed on the outer peripheral surface thereof so that the elastic clip (120) is fitted on the receiving groove. [14] Vehicle steering device comprising: a steering wheel; a pinion shaft connected to the steering wheel for rotating along with the rotation of the steering wheel; a rack bar that is moved linearly by a rotational force of the pinion shaft; a ball nut (20) coupled to an outer side of the rack bar; a drive unit for providing an auxiliary force for a rectilinear movement of the rack bar; a bearing (110) comprising an inner ring (111) fixed to an outer side of the ball nut (20), an outer ring (112) arranged outside the inner ring (111), with a ball interposed therebetween, and a sealing element (113) provided between the inner ring (111) and the outer ring (112); and an elastic clamp (130) coupled to an outer side of the bearing (110); wherein the elastic clamp (130) comprises: a body (131) pressed against an outer peripheral surface of the outer ring (112); first bent portions (132) bent from both ends of the body (131) to a boundary between the outer ring (112) and the sealing member (113); second bent portions (133) bent laterally from the outer ring (112) from respective ends of the first bent portions (132); and elastic portions (134) extending from the respective second curved portions (133) and projecting laterally from the outer ring (112) so as to each have a curvature. [15] A vehicle steering device according to claim 14, wherein the elastic clamp (130) comprises: a body (131) pressed against an outer peripheral surface of the outer ring (112); fixing portions bent toward the outer ring (112) sides from both ends of the body (121); and elastic portions (134) extending from respective ends of the fastening portions and projecting laterally from the outer ring (112) so as to each have a curvature.

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