JP2007062450A - Rack shaft support device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rack shaft support device capable of restricting movement of a plug without requiring an exclusive step and certainly preventing the plug from being removed from a housing. <P>SOLUTION: The rack shaft support device 5 is provided with the housing 3 for slidably storing the rack shaft 4; a guide hole 8 provided on the housing 3; a support member for supporting the rack shaft 4 slidably in an axial direction; the plug 11 for sealing an opening of the guide hole 8; and a spring 12 interposed between the support member 10 and the plug 11 and urging the support member 10 to the rack shaft 4 side. The plug 11 includes a body 19; an elastic arm 21 supported by the body 19 at cantilever; and an engagement claw 22 provided on a free end 21a of the elastic arm 21. The plug 11 is locked to a predetermined threading position by engaging the engagement claw 22 with an engagement groove 29 formed on an inner peripheral surface 8a of the guide hole 8. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rack shaft support device applied to a rack and pinion type steering device.

  In a rack and pinion type steering device, the rack shaft is typically supported by a rack shaft support device. The rack shaft support device includes a support member that is held in a guide hole formed in a housing so as to be able to advance and retreat, a plug that seals the opening of the guide hole, and a biasing member that is interposed between the support member and the plug. I have. The rack shaft is supported by a support member so as to be slidable in the axial direction, and the support member is biased toward the rack shaft by a biasing member. Further, the male screw part formed in the plug and the female screw part formed in the guide hole are screwed together so that the plug is held in the guide hole.

In general, the male screw portion is provided with a locking mechanism so that the relative position of the plug to the housing does not change. This locking is performed, for example, by tightening a lock nut on the plug or caulking the housing (see, for example, Patent Document 1 and Patent Document 2).
JP 2005-132287 A JP 2005-170109 A

  However, in any of the methods described in Patent Document 1 or Patent Document 2, a troublesome work for preventing the plug from being loosened is required. For example, Patent Document 1 requires a complicated operation of tightening the lock nut while holding the plug so that the plug does not rotate with the lock nut. Moreover, in patent document 2, the complicated operation | work of caulking with a predetermined caulking load using a caulking apparatus is required.

Further, in the above-described locking method, if the lock nut is loosened or the caulking is removed, the plug may be detached from the housing.
The present invention has been made based on such a background, can control the movement of the plug without requiring a dedicated process, and can reliably prevent the plug from being detached from the housing. An object is to provide a rack shaft support device.

  In order to achieve the above object, a housing (3) that slidably receives a rack shaft (4), a guide hole (8) provided in the housing, and a guide shaft (8) that is movably held in the guide hole. A support member (10) that is slidably supported in the axial direction, a retraction position (P1) of the support member, a plug (11, 110) that seals the opening of the guide hole, and the support member and the plug And an urging member (12) for urging the support member toward the rack shaft. The plug is screwed onto the outer peripheral surface (23) and the threaded portion (18) on the inner peripheral surface of the guide hole. A main body (19) having a round cross section having a threaded portion (17) to be joined, an elastic arm (21, 210) supported in a cantilevered manner by the main body, and an elastic arm provided at a free end (21a) of the elastic arm Engaging claws (22, 2) which are displaced in the radial direction (R1) of the main body with the swing of 20), and an engagement groove (29) is formed on the inner peripheral surface of the guide hole to lock the plug in a predetermined screwing position by engaging with the engagement claw. A shaft support device (100).

  According to the present invention, the plug is screwed into the guide hole of the housing in a state where the elastic arm is elastically deformed and the engaging claw is displaced inward in the radial direction of the plug. When the plug is screwed to a predetermined position, the engaging claw is displaced outward in the radial direction of the plug by the restoring force of the elastic arm and engages with the engaging groove. The plug is locked at a predetermined screwing position by the engagement between the engagement claw and the engagement groove. As a result, the retracted position of the support member can be accurately positioned by the plug. Further, it is possible to reliably prevent the plug from being loosened and removed from the guide hole.

In the present invention, the elastic arm extends in the axial direction of the main body and a plurality of the elastic arms are arranged in the circumferential direction of the main body, and a slit (25) extending in the axial direction of the main body is formed between the elastic arms. There may be. In this case, a plurality of engaging claws are provided side by side in the circumferential direction of the plug, and the plug can be reliably locked.
In the present invention, the plug may include a receiving portion (20, 200) provided on the main body for receiving the urging member, and an annular groove (31) for partitioning the receiving portion and the plurality of elastic arms. is there. In this case, the biasing member can be received by the receiving portion of the plug body. Moreover, the space for the elastic arm to bend radially inward can be easily secured by the annular groove.

In the present invention, the plurality of elastic arms may include a receiving portion that receives a biasing member. In this case, the biasing member can be received by the receiving portion of the elastic arm.
Further, in the present invention, the engaging claw has an inclined shape for converting a force (F1) for pushing the plug into the inlet of the guide hole into a force (F2) for displacing the engaging claw radially inward of the plug. The rack shaft support device includes a cam surface (28). In this case, when the inclined cam surface is pressed against the peripheral edge portion of the entrance of the guide hole, the engaging claw can be easily displaced inward in the radial direction of the plug.

In the present invention, the plug may be an integrally formed product of synthetic resin. In this case, the elastic arm and the engaging claw can be easily formed integrally with the main body. Further, the elasticity of the elastic arm can be easily obtained.
In the above description, the alphanumeric characters in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a cross-sectional view of a rack and pinion type steering device to which a rack shaft support device according to an embodiment of the present invention is applied.
Referring to FIG. 1, a steering apparatus 100 includes a pinion shaft 1 connected to a steering member such as a steering wheel (not shown), a pinion 2 provided at the tip of the pinion shaft 1, and a rack shaft that meshes in a housing 3. 4 and a rack shaft support device 5 for pressing the rack shaft 4 against the pinion 2.

  The pinion shaft 1 is rotatably supported in the housing 3 by two bearings 6a and 6b, and the pinion 2 is rotated by the rotation of the pinion shaft 1. Both ends of the rack shaft 4 are supported by a bearing member (not shown) held by the housing 3 so as to be slidable in the axial direction (direction perpendicular to the paper surface of FIG. 1). Although not shown, wheels are coupled to both ends of the rack shaft 4 via tie rods.

The housing 3 has an overhanging portion 7 that protrudes on the opposite side of the pinion 2 with the rack shaft 4 interposed therebetween. A guide hole 8 is formed in the overhang portion 7, and one end of the guide hole 8 is open to the top portion 7 a of the overhang portion 7.
The rack shaft support device 5 includes a support member 10 that slidably supports the rack shaft 4 in the axial direction via a pad 9, a plug 11 that seals the guide hole 8, and a space between the support member 10 and the plug 11. And a spring 12 that biases the support member 10 toward the rack shaft 4.

  The support member 10 is formed in a columnar shape and is accommodated so as to be able to advance and retract in the depth direction X1 of the guide hole 8. A curved surface 13 for attaching the pad 9 is formed at one end 10 a of the support member 10, and the pad 9 attached to the curved surface 13 is in sliding contact with the rack shaft 4. The other end 10b of the support member 10 is formed with a recess 14 in which the spring 12 is accommodated. A pair of annular grooves 15 extending in the circumferential direction are formed on the outer peripheral surface 10 c of the support member 10, and an annular elastic member 16 such as an O-ring is held in the annular groove 15. The elastic member 16 is compressed between the inner peripheral surface 8 a of the guide hole 8 and the annular groove 15 of the support member 10. Thereby, the support member 10 is elastically supported in the radial direction Y1 of the guide hole 8. As a result, rattling of the support member 10 in the guide hole 8 can be suppressed.

  The plug 11 is made of a synthetic resin. The guide hole 8 can be sealed with the plug 11 by screwing the male screw portion 17 and the female screw portion 18 together. The plug 11 is held in the guide hole 8 in a state where a predetermined interval S (for example, 0.1 mm) is provided between the one end 11 a of the plug 11 and the other end 10 b of the support member 10. When the other end 10b of the support member 10 contacts the one end 11a of the plug 11, the retracted position P1 of the support member 10 toward the plug 11 can be regulated.

The spring 12 is sandwiched between the bottom surface 14 a of the recess 14 and one end 11 a of the plug 11. The support member 10 is urged toward the rack shaft 4 by the spring 12, whereby backlash between the pinion 2 and the rack shaft 4 can be removed.
FIG. 2 is a side view schematically showing the plug, and FIG. 3 is a plan view of the plug as viewed from an arrow III. 2 and 3, the plug 11 includes a main body 19 having a round cross section, a receiving portion 20 provided on the main body 19 for receiving the spring 12, and a plurality of elastic arms supported in a cantilever manner on the main body 19. 21 and engaging claws 22 provided on each elastic arm 21. The plug 11 is made of synthetic resin, and the main body 19, the receiving portion 20, the elastic arms 21 and the engaging claws 22 are integrally formed.

  The main body 19 has a cylindrical large-diameter portion 191 and a small-diameter portion 192 having a smaller diameter than the large-diameter portion 191. On the outer peripheral surface 23 of the large-diameter portion 191, the male screw portion 17 that is screwed with the female screw portion 18 of the inner peripheral surface 8a of the guide hole 8 is formed. A tool engagement hole 24 is formed in the rear surface 19a of the large diameter portion 191. By engaging a tool (not shown) with the tool engagement hole 24 and rotating the plug 11, the plug 11 can be tightened or loosened. Thus, the predetermined distance S can be provided between the plug 11 and the support member 10 by adjusting the screwing amount of the plug 11 into the guide hole 8.

The small diameter portion 192 is formed in a columnar shape and extends from the front surface 19b of the large diameter portion 191 in the axial direction Z1 of the main body 19. The small diameter part 192 is arranged coaxially with the large diameter part 191. A receiving portion 20 is provided on one end surface of the small diameter portion 192, and the spring 12 is received by the receiving portion 20.
Each of the plurality of elastic arms 21 is formed in a substantially quadrangular prism shape, and extends from the front surface 19b of the large diameter portion 191 in the axial direction Z1 of the main body 19. The base end portions of the plurality of elastic arms 21 are arranged along the periphery of the front surface 19b of the large diameter portion 191. The plurality of elastic arms 21 surround the small diameter portion 192 and are arranged in an annular shape concentric with the small diameter portion 192. The plurality of elastic arms 21 are arranged at equal intervals in the circumferential direction A1 of the main body 19. Between each elastic arm 21 adjacent to the circumferential direction A1, a slit 25 extending in the axial direction Z1 of the main body 19 is provided. The elastic arms 21 adjacent to each other in the circumferential direction A1 are partitioned by the slits 25.

  The engaging claw 22 is provided at the free end 21 a of each elastic arm 21, and protrudes outward from the radial direction R <b> 1 of the main body 19 from each elastic arm 21. The engaging claws 22 include a first engaging surface 26 provided on the free end 21a side of each elastic arm 21, a second engaging surface 27 provided on the fixed end 21b side of each elastic arm 21, and a first And an inclined cam surface 28 connecting between the engagement surface 26 and the second engagement surface 27. The first engagement surface 26 and the second engagement surface 27 are surfaces perpendicular to the axial direction Z1 of the main body 19. The inclined cam surface 28 is inclined inward in the radial direction R <b> 1 from the second engagement surface 27 to the first engagement surface 26.

  Similar to each elastic arm 21, the engaging claw 22 concentrically surrounds the small diameter portion 192 and is arranged in an annular shape. The outermost diameter D1 of the engaging claws 22 arranged in an annular shape is larger than the outer diameter D2 of the large diameter portion 191 in a state where the engaging claws 22 are not elastically deformed. The engaging claw 22 is engaged with an engaging groove 29 having a cross-sectional groove shape formed on the inner peripheral surface 8 a of the guide hole 8. Thereby, the plug 11 can be locked in a predetermined screwing position.

  An annular groove 31 is provided between the plurality of elastic arms 21 and the outer periphery of the small diameter portion 192. Due to the annular groove 31, a certain space is provided between each elastic arm 21 and the outer circumference of the small diameter portion 192. Thereby, each elastic arm 21 is bent inward in the radial direction R1, and the engaging claw 22 can be displaced inward in the radial direction R1. Each elastic arm 21 and the receiving portion 20 are partitioned by the annular groove 31.

  FIG. 4 is a partial cross-sectional schematic view for explaining a procedure for locking the plug 11 by screwing it into the guide hole 8. Referring to FIG. 4, in order to lock plug 11 in guide hole 8, plug 11 is screwed into guide hole 8 with a plurality of elastic arms 21 being displaced inward in radial direction R <b> 1 of main body 19. Just do it. That is, when the engaging claw 22 reaches the position of the engaging groove 29 by screwing, the engaging claw 22 is deformed outward in the radial direction R1 by the elastic restoring force of the elastic arm 21, and the engaging claw 22 is engaged. Automatic engagement with the mating groove 29 is achieved.

  More specifically, first, as shown in FIG. 4A, the cam surface 28 of the engaging claw 22 and the opening peripheral edge portion 30 of the guide hole 8 are brought into contact with each other so that the plug 11 is inserted into the guide hole 8. Push in toward. At this time, the force F1 for pushing the plug 11 toward the guide hole 8 is converted into a force F2 for displacing the engaging claw 22 inward in the radial direction R1 of the main body 19 by the cam surface 28. Thereby, each elastic arm 21 is elastically deformed, and the engaging claw 22 is displaced inward in the radial direction R <b> 1 of the main body 19, so that the plug 11 can be easily pushed into the guide hole 8.

  After the plug 11 is pushed into the guide hole 8, as shown in FIG. 4B, the plug 11 is rotated and the male screw portion 17 and the female screw portion 18 are screwed together. The opening of the guide hole 8 is sealed by the plug 11 by screwing the male screw portion 17 and the female screw portion 18 together. In addition, when the plug 11 is screwed to a predetermined screwing position of the guide hole 8, that is, the position where the engagement claw 22 coincides with the engagement groove 29, each elastic arm 21 is restored by the elastic restoring force, and the engagement claw 22 is displaced outward in the radial direction R1. As a result, the engagement claw 22 engages with the engagement groove 29, and the plug 11 is locked.

  In this way, a predetermined interval S is secured between the one end 11 a of the plug 11 and the other end 10 b of the support member 10 in a state where the plug 11 is locked. The amount of this predetermined interval S can be adjusted. That is, the distance between the first surface 29a and the second surface 29b, which are the surfaces facing the first engagement surface 26 and the second engagement surface 27 of the engagement groove 29, is greater than the thickness of the engagement claw 22. The dimensions of the engagement groove 29 and the engagement claw are set so as to increase the fixed amount. Therefore, the amount of the predetermined interval S can be adjusted by the predetermined amount.

  Further, the engagement claw 22 engages with the engagement groove 29, so that the movement of the plug 11 in the depth direction X1 of the guide hole 8 can be restricted. Specifically, the movement of the plug 11 toward the support member 10 is restricted by the first engagement surface 26 being in contact with the first surface 29a. Further, when the second engagement surface 27 comes into contact with the second surface 29b, the removal of the plug 11 from the guide hole 8 is restricted.

  As described above, according to this embodiment, the plug 11 can be screwed into the guide hole 8 by elastically deforming the plurality of elastic arms 21 inward in the radial direction R1. By screwing the plug 11 to a predetermined screwing position, each elastic arm 21 is restored and the engaging claw 22 and the engaging groove 29 are engaged. Thereby, the plug 11 is locked at a predetermined screwing position. As a result, the plug 11 can accurately position the retracted position P1 of the support member 10. Further, it is possible to reliably prevent the plug 11 from being loosened and pulled out from the guide hole 8.

FIG. 5 is a cross-sectional view schematically showing a part of a plug according to another embodiment of the present invention. 5, the same components as those shown in FIGS. 2 and 3 described above are denoted by the same reference numerals as those in FIGS. 2 and 3, and the description thereof is omitted.
The main difference of the present embodiment from the embodiment of FIG. 2 is that a receiving portion 200 for receiving the spring 12 is provided on the end face of the engaging claw 220.

The plug 110 includes an elastic arm 210 and an engaging claw 220. The engaging claw 220 is provided at the free end 21 a of the elastic arm 210 and includes the receiving portion 200. The receiving portion 200 is provided on the end surface of the engagement claw 220 and is on the same plane as the first engagement surface 26.
Thereby, the engaging claw 220 provided with the receiving portion 200 can not only lock the screwing position of the plug 110 but also receive the spring 12.

  The present invention is not limited to the contents of the above embodiments, and various modifications can be made within the scope of the claims.

1 is a cross-sectional view of a rack and pinion type steering device to which a rack shaft support device according to an embodiment of the present invention is applied. It is the side view which showed the plug schematically. It is the top view which looked at the plug from arrow III. FIG. 5 is a partial cross-sectional schematic diagram for explaining a procedure for coupling a plug and a guide hole. FIG. 5 is a cross-sectional view schematically showing a part of a plug according to another embodiment of the present invention. DESCRIPTION OF SYMBOLS 3 ... Housing, 4 ... Rack shaft, 5 ... Rack shaft support apparatus, 8 ... Guide hole, 8a ... Inner peripheral surface, 10 ... Support member, 11, 110 ... Plug, 12... Spring (biasing member), 17... Male threaded portion (threaded portion), 18... Female threaded portion (threaded portion on inner peripheral surface), 19. .... Receiving part, 21, 210 ... elastic arm, 21a ... free end, 22, 220 ... engaging claw, 23 ... outer peripheral surface, 25 ... slit, 28 ... cam surface 29 ... engagement groove, 31 ... annular groove, A1 ... circumferential direction, F1 ... pushing force, F2 ... displacement force, P1 ... retracted position, R1 ... diameter Direction, Z1 ... axial direction

Claims (6)

A housing for slidably receiving the rack shaft;
A guide hole provided in the housing;
A support member that is held in the guide hole so as to freely advance and retract, and supports the rack shaft so as to be slidable in the axial direction;
A plug that positions the retracted position of the support member and seals the opening of the guide hole;
A biasing member that is interposed between the support member and the plug and biases the support member toward the rack shaft;
The plug includes a main body having a round cross section having a threaded portion that is threadedly engaged with a threaded portion of the inner peripheral surface of the guide hole, an elastic arm that is cantilevered by the main body, and a free end of the elastic arm. And an engaging claw that is displaced in the radial direction of the main body as the elastic arm swings,
A rack shaft support device, wherein an engagement groove for locking the plug at a predetermined screwing position by engaging with the engagement claw is formed on an inner peripheral surface of the guide hole.   2. The elastic arm according to claim 1, wherein the elastic arm extends in the axial direction of the main body and a plurality of the elastic arms are arranged in the circumferential direction of the main body, and a slit extending in the axial direction of the main body is formed between the elastic arms. A rack shaft support device.   3. The rack shaft support device according to claim 2, wherein the plug includes a receiving portion that is provided on the main body and receives the biasing member, and an annular groove that partitions the receiving portion and the plurality of elastic arms.   The rack shaft support device according to claim 2, wherein the plurality of elastic arms includes a receiving portion that receives a biasing member.   5. The engagement claw according to claim 1, wherein the engagement claw has an inclined shape for converting a force for pushing the plug into the inlet of the guide hole into a force for displacing the engagement claw radially inward of the plug. A rack shaft support device including a cam surface.   6. The rack shaft support device according to claim 1, wherein the plug is an integrally formed product of synthetic resin.

Images