JP2009173090A - Vehicular steering unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular steering unit that reliably prevents a holder of a pinion shaft supporting bearing from coming off. <P>SOLUTION: A threaded member 22 screwed into the inner circumference of the pinion housing 2 is equipped with a ring-shaped body 31, which presses the top end 27a of the outer ring 27 of a first bearing 3 that rotates the pinion shaft 5. A regulator member 36 is provided protruding from the inner circumference 31b of the body 31 in the diametrical direction Y1. The minimum inside diameter d1 of the regulator member 36 is smaller than the outside diameter d2 of the inner ring 28 (d1<d2). The regulator member 36 prevents the holder 30 from coming off. Should the holder 30 break and come off, the regulator member 36 prevents the inner ring 28 from coming off. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rack and pinion type vehicle steering apparatus.

As a rack and pinion type vehicle steering device, for example, a vehicle steering device of Patent Document 1 has been proposed. In the vehicle steering apparatus disclosed in Patent Document 1, a bearing that rotatably supports a pinion shaft in a cylindrical housing is provided. Axial relative movement between the inner ring of the bearing and the pinion shaft is restricted. A so-called top plug is screwed into the inner peripheral threaded portion of the inlet at the top of the housing. Since the top plug engages with the outer ring of the bearing, the bearing and the pinion shaft are prevented from being pulled out from the inlet of the housing.
Japanese Patent Laid-Open No. 2005-14815

However, for some reason, the cage may be pulled out of the bearing and enter the annular top plug.
The cause is that the ball cannot move smoothly due to variations in the dimensions of the pinion shaft and the bearing and rusting inside the bearing, and as a result, the cage is pushed out of the bearing by the ball that has advanced and delayed. There are cases.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a vehicle steering apparatus that can reliably prevent the retainer from being removed.

  In order to solve the above-mentioned problems, the present invention includes a cylindrical housing (2) having an inlet (20) at the top and a threaded portion (21) on the inner periphery of the inlet, and being inserted into the housing. , A pinion shaft (5) having a pinion (5a) meshing with the rack shaft, a bearing (3) held by the housing and rotatably supporting the pinion shaft, and an annular screw member screwed into the threaded portion of the housing ( 22), and the bearing includes an outer ring (27) whose movement downward in the axial direction is restricted by the housing, an inner ring (28) that can move along the axial direction with the pinion shaft, and an outer ring and an inner ring A plurality of rolling elements (29) interposed therebetween, and a retainer (30) that holds the rolling elements, and the screw member is configured to fix the outer ring in the axial direction (the upper end of the outer ring ( 27a) is pressed And Jo body (31) and is characterized in that it comprises projecting radially inward from the inner periphery of the main body (31b), regulating portion for regulating the pull-out of the retainer and (36).

According to the present invention, the screw member screwed into the screw portion of the inlet at the upper part of the housing includes the annular main body that presses the upper end of the outer ring of the bearing that enables the pinion shaft to rotate, and the inner periphery of the main body By means of the restricting portion protruding radially inward from the bearing, it is possible to prevent the bearing retainer from being pulled out.
The minimum inner diameter (d1) of the restricting portion is smaller than the outer diameter (d2) of the inner ring, and the restricting portion may restrict the removal of the inner ring from the housing. Item 2). In that case, it is possible to reliably prevent the cage from being pulled out. In addition, even if the cage is pulled out due to breakage or the like, the inner ring is prevented from being pulled out by the restricting portion. Therefore, the bearing and the pinion shaft are reliably prevented from being removed from the housing.

  In addition, an annular member (39) that is held by the pinion shaft and abuts on the upper end (28a) of the inner ring to restrict the relative movement of the pinion shaft and the inner ring in the axial direction is provided. The outer diameter (d3) of (39) may be larger (claim 3). In that case, for example, the positions of the screw member and the annular member may be partially overlapped with respect to the axial direction of the pinion shaft, so that the axial size can be reduced.

Further, the restricting portion may be provided with a relief portion (37) for preventing interference with the upper end of the inner ring (claim 4). In that case, in order to prevent the retainer from being pulled out, even if the restricting portion protrudes radially inward of the annular main body of the screw member, interference between the restricting portion and the inner ring is prevented by the escape portion. .
The minimum inner diameter of the restricting portion may be larger than the outer diameter of the inner ring and smaller than the inner diameter (d4) of the outer ring. In that case, since the retainer can be prevented from being pulled out by the restricting portion, the bias of the plurality of rolling elements can be prevented in the circumferential direction of the bearing, and as a result, the bearing and the pinion shaft can be reliably prevented from being pulled out.

  And an annular seal member (35) that is held on the inner periphery of the screw member main body and seals between the inner periphery of the screw member main body and the outer periphery (5b) of the pinion shaft, There is a case where movement of the seal member downward in the axial direction is restricted by the restricting portion (claim 6). In that case, the screw member and the seal member can be handled as an integral unit, and therefore, it is easy to assemble, and can be easily removed and maintained during repair.

In addition, it is preferable to provide a seal member that seals between the outer periphery of the main body of the screw member and the inner periphery of the housing in order to prevent moisture from entering from the outside. As the sealing member, for example, liquid packing can be exemplified.
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.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic cross-sectional view showing a main part of a vehicle steering apparatus according to an embodiment of the present invention.
Referring to FIG. 1, a vehicle steering apparatus 1 is a rack and pinion type steering apparatus. A vehicle steering apparatus 1 includes a cylindrical pinion housing 2, a pinion shaft 5 rotatably supported by the pinion housing 2 via a first bearing 3 and a second bearing 4, and a pinion 5a of the pinion shaft 5. And a rack shaft 6 having rack teeth 6a meshing with each other. The pinion shaft 5 and the rack shaft 6 constitute a rack and pinion mechanism 7 as a turning mechanism.

  The pinion shaft 5 is connected to a steering member 8 made of, for example, a steering wheel so as to be able to rotate along with the steering shaft 9a and an intermediate member 9b. The rack shaft 6 is supported by a cylindrical rack housing (not shown) connected in a crossing manner with the pinion housing 2 so as to be movable in the axial direction (direction perpendicular to the paper surface). Although not shown, both ends of the rack shaft 6 are coupled to the steered wheels via tie rods, and the rack shaft 6 moves in the axial length direction as the steering member 8 rotates, and steering is performed. It is like that.

  The pinion housing 2 is provided with a cylindrical support housing 10 on the opposite side of the pinion shaft 5 across the rack shaft 6, and a rack shaft support device 11 is attached to the support housing 10. The rack shaft support device 11 includes a cylindrical support yoke 12 as a support member accommodated in the support housing 10 so as to be able to advance and retreat back and forth, and a sealing member 13 fixed to a screw portion 10a at the entrance of the support housing 10. And a biasing member 14 made of, for example, a compression coil spring, which is interposed between the support yoke 12 and the sealing member 13 and biases the rack shaft 6 toward the pinion shaft 5 via the support yoke 12. .

The front surface 12a of the support yoke 12 is formed with a recess 15 that supports the rack shaft 6 so as to be slidable in the axial direction. A pad 16 made of a low friction member that is in sliding contact with the rack shaft 6 is attached to the recess 15.
A predetermined gap S is formed between the front surface 13 a of the sealing member 13 and the rear surface 12 b of the support yoke 12. The amount of the gap S is strictly adjusted to 0.1 mm, for example, by adjusting the screwing position of the sealing member 13.

An annular elastic member 17 made of, for example, an O-ring is accommodated in a pair of circumferential grooves formed on the outer peripheral surface of the support yoke 12, and these elastic members 17 elastically contact the inner periphery of the support housing 10. Thus, the support yoke 12 is elastically supported in the radial direction to prevent the support yoke 12 from rattling.
On the rear surface 13b of the sealing member 13, for example, a tool engagement hole 18 having a polygonal cross section for engaging with a tool for rotating the sealing member 13 is formed.

  The pinion housing 2 has an accommodation hole 19 for accommodating the lower part of the pinion shaft 5. A screw portion 21 is formed on the inner periphery of the inlet 20 of the accommodation hole 19, and an annular screw member 22 is screwed into the screw portion 21. In addition, a cylindrical dust cover 23 is placed on the upper end of the pinion housing 2 in order to prevent moisture and the like from entering from the inlet 20 of the accommodation hole 19. The dust cover 23 has an insertion hole 24 through which the pinion shaft 5 is inserted in a liquid-tight manner.

The first bearing 3 and the second bearing 4 are arranged above and below the pinion 5 a of the pinion shaft 5, and corresponding bearing holding portions provided on the inner periphery of the accommodation hole 19 of the pinion housing 2, respectively. 25, 26. A bearing holding portion 25 for the first bearing 3 is provided adjacent to the screw portion 21.
The first bearing 3 is composed of, for example, a ball bearing as a rolling bearing, and the second bearing 4 is composed of, for example, a cylindrical roller bearing as a rolling bearing. The first bearing 3 includes an outer ring 27 in which the downward movement in the axial direction X1 is restricted by the pinion housing 2, an inner ring 28 that can move along the axial direction X1 with the pinion shaft 5, and the outer ring 27 and the inner ring 28. A rolling element 29 composed of a plurality of balls interposed therebetween and a crown-shaped cage 30 that holds the rolling element 29 are included.

The pocket 30a for holding each rolling element 29 in the cage 30 is opened downward.
2 and 3, the screw member 22 includes an annular main body 31 that presses the upper end 27a of the outer ring 27 in order to fix the outer ring 27 in the axial direction X1. With reference to FIG. 1, a screw portion 32 formed on the outer periphery 31 a of the main body 31 is screwed into the screw portion 21 of the inlet 20 of the accommodation hole 19. The outer ring 27 is sandwiched between an annular step portion 33 formed on the inner periphery of the accommodation hole 19 and the abutting portion 34 on the lower surface of the screw member 22, so that axial movement relative to the pinion housing 2 is restricted.

An annular seal member 35 is held on the inner periphery 31 b of the main body 31, and the seal member 35 seals between the inner periphery 31 b of the main body 31 and the outer periphery 5 b of the pinion shaft 5. As shown in FIG. 3, the seal member 35 includes a metal core 35 a and a rubber member 35 b having a lip (not shown) that engages with the outer periphery 5 b of the pinion shaft 5.
2 and 3, the screw member 22 includes a restricting portion 36 that protrudes inward in the radial direction Y1 from the inner circumference 31b of the main body 31, and the restricting portion 36 includes the first restricting portion 36. It fulfills the function of regulating the removal of the cage 28 of the bearing 3. The upper part of the inner periphery 31b of the main body 31 has an enlarged diameter, and serves as a tool engaging portion 40 with which a tool for rotating the screw member 22 is engaged. The tool engaging portion 40 has a polygonal cross section such as a hexagon.

  As shown in FIG. 3, the minimum inner diameter d1 of the restricting portion 36 (corresponding to the diameter of the inner periphery 36a of the restricting portion 36) is smaller than the outer diameter d2 of the inner ring 28 (d1 <d2). As a result, the restriction portion 36 prevents the inner ring 28 from being removed from the pinion housing 2. Further, the restricting portion 36 is provided with an annular relief portion 37 for preventing interference with the upper end 28a of the inner ring 28. Specifically, an escape portion 37 is formed on the lower surface 36 b of the restricting portion 36.

The seal member 35 is in contact with the upper surface 36c of the restricting portion 36, and the restricting portion 36 restricts the downward movement of the seal member 35 in the axial direction X1.
On the other hand, as shown in FIG. 1, the inner ring 28 is sandwiched between an annular step portion 38 provided on the outer periphery of the pinion shaft 5 and an annular member 39 fixed to the outer periphery of the pinion shaft 5. Axial movement with respect to is restricted. As shown in FIG. 4, a plurality of outward projections 39 b arranged at equal intervals in the circumferential direction are provided on the outer periphery 39 a of the annular member 39, and the outer diameter of the outward projection 39 b is equal to that of the annular member 39. The maximum outer diameter is d3. The diameter of the outward projection 39b is the same as the original shape of the annular material when the outer periphery of the annular material is caulked (plastically deformed) at a plurality of locations (four locations in the example in the figure) and radially inward. Corresponds to the outer diameter of the remaining part.

  As shown in FIG. 3, at least a part of the restricting portion 36 and the annular member 39 are opposed to each other in the radial direction. The minimum inner diameter d1 of the restricting portion 36 is set larger than the maximum outer diameter d3 of the annular member 39. Thereby, with respect to the axial direction X1 of the pinion shaft 5, it becomes possible to arrange the restricting portion 36 and the annular member 39 at a position where at least a part of each other overlaps, which can contribute to downsizing of the axial direction X1.

  According to the present embodiment, the screw member 22 screwed into the screw portion 21 of the inlet 20 at the top of the pinion housing 2 presses the upper end 27a of the outer ring 27 of the first bearing 3 that enables the pinion shaft 5 to rotate. The retaining portion 30 of the first bearing 3 is reliably prevented from being pulled out by the restricting portion 36 that protrudes inward in the radial direction Y1 from the inner periphery 31b of the main body 31. Can do.

Specifically, the minimum inner diameter d1 of the restricting portion 36 is smaller than the outer diameter d2 of the inner ring 28 (d1 <d2). Therefore, even if the retainer 30 is removed, the restriction portion 36 prevents the inner ring 28 from being removed, so that the first bearing 3 and the pinion shaft 5 can be removed from the pinion housing 2. It is surely prevented.
The annular member 39 held by the pinion shaft 5 is in contact with the upper end 28a of the inner ring 28, so that the relative movement of the pinion shaft 5 and the inner ring 28 in the axial direction X1 is restricted. The minimum inner diameter d1 is made larger than the maximum outer diameter d3 of the annular member 39. Thereby, the positions of the screw member 22 and the annular member 39 can be partially overlapped with respect to the axial direction X1 of the pinion shaft 5, and downsizing in the axial direction X1 can be achieved.

Further, since the relief portion 37 is provided in the restriction portion 36, even if the restriction portion 36 protrudes inward in the radial direction Y <b> 1 of the main body 31 of the screw member 22 in order to prevent the inner ring 28 from being pulled out, Interference between the restricting portion 36 and the inner ring 28 can be reliably prevented by the escape portion 37.
Further, an annular seal member 35 for sealing between the inner periphery 31 b of the main body 31 and the outer periphery 5 b of the pinion shaft 5 is held on the inner periphery 31 b of the main body 31 of the screw member 22. The downward movement in the axial direction X1 is restricted by the restriction part 36. As a result, the screw member 22 and the seal member 35 can be handled as an integral unit. Therefore, the screw member 22 and the seal member 35 can be easily assembled, and can be easily removed and maintained during repair.

In order to seal between the threaded portion 32 of the outer periphery 31b of the main body 31 of the screw member 22 and the inner periphery of the pinion housing 2, for example, a seal member such as a liquid packing is used so that moisture can enter from the outside. It is preferable for reliably preventing the above.
Next, FIG. 5 shows a cross section of the main part of the vehicle steering apparatus 1 according to another embodiment of the present invention. Referring to FIG. 5, the present embodiment is different from the embodiment of FIG. 3 in that in the embodiment of FIG. 3, the minimum inner diameter d1 of the restricting portion 36 of the screw member 22 is Although it is smaller than the outer diameter d2 of the inner ring 28 (d1 <d2), in the present embodiment, the minimum inner diameter d1 of the restricting portion 360 of the screw member 22 is the outer diameter d2 of the inner ring 28 of the first bearing 3. (D1> d2).

  Also in the present embodiment, since the retainer 30 can be prevented from being pulled out by the restricting portion 360, the bias of the plurality of rolling elements 29 can be prevented in the circumferential direction of the first bearing 3, and as a result, the first The bearing 3 and the pinion shaft 5 can be prevented from being pulled out. If the inner ring 28 is prevented from being pulled out by the restricting portion 36 as in the embodiment of FIG. 3, a more reliable fail safe is achieved. However, even in the present embodiment, a sufficiently effective fail safe is achieved. Can fulfill the function.

In addition, even if the cage is broken, the first bearing 3 can be replaced and other maintenance can be performed without damaging the seal member 35.
The present invention is not limited to the above-described embodiments. For example, as shown in FIGS. 6A and 6B, the restricting portion 361 is provided on the inner periphery 31 b of the main body 31 of the screw member 22. You may be comprised by the some protrusion arrange | positioned cyclically | annularly at intervals in the circumferential direction.

  Further, as shown in FIG. 7, an annular elastic member 41 made of, for example, an O-ring is interposed between the lower part of the outer periphery 31 b of the main body 31 of the screw member 22 and the inner periphery of the pinion housing 2. The space between the outer periphery 31b and the inner periphery of the pinion housing 2 may be sealed. In this case, the above liquid packing is abolished.

It is sectional drawing of the principal part of the steering apparatus for vehicles of one embodiment of this invention. It is sectional drawing of a screw member. It is an expanded sectional view of the principal part of FIG. It is sectional drawing of a pinion shaft and an annular member. It is sectional drawing of the principal part of the steering apparatus for vehicles of another embodiment of this invention. (A) is sectional drawing of the screw member of another embodiment of this invention, (b) is a bottom view of the screw member. It is sectional drawing of the principal part of the steering apparatus for vehicles of another embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vehicle steering device, 2 ... Pinion housing (housing), 3 ... 1st bearing (bearing), 5 ... Pinion shaft, 5b ... Outer periphery, 6 ... Rack shaft, 19 ... Housing hole, 20 ... Inlet, 21 ... Threaded part, 22 ... Screw member, 27 ... Outer ring, 27a ... Upper end, 28 ... Inner ring, 28a ... Upper end, 29 ... Rolling element, 30 ... Retainer, 31 ... Main body, 31a ... Outer periphery, 31b ... Inner periphery, 32 ... Screw 33, annular stepped portion, 34 ... abutting portion, 35 ... sealing member, 36, 360, 361 ... regulating portion, 37 ... relief portion, 38 ... annular end portion, 39 ... annular member, X1 ... axial direction, Y1 ... radial direction, d1 ... minimum inner diameter of restricting portion, d2 ... outer diameter of inner ring, d3 ... maximum outer diameter of annular member, d4 ... inner diameter of outer ring

Claims (6)

A cylindrical housing having an inlet at the top and a threaded portion on the inner periphery of the inlet;
A pinion shaft having a pinion that is inserted into the housing and meshes with the rack shaft; a bearing that is held by the housing and rotatably supports the pinion shaft;
An annular screw member screwed into the screw portion of the housing,
The bearing includes an outer ring whose movement downward in the axial direction is restricted by the housing, an inner ring that can move in the axial direction with respect to the pinion shaft, a plurality of rolling elements interposed between the outer ring and the inner ring, and the rolling elements. A cage for holding a moving body,
The screw member includes an annular main body that presses the upper end of the outer ring in order to clamp the outer ring in the axial direction, and a restricting portion that protrudes radially inward from the inner periphery of the main body and restricts removal of the cage. And a vehicle steering apparatus. In claim 1, the minimum inner diameter of the restriction portion is smaller than the outer diameter of the inner ring,
A vehicle steering apparatus, wherein the restriction portion restricts removal of the inner ring from the housing. In Claim 2, provided with an annular member that is held by the pinion shaft and abuts on the upper end of the inner ring to restrict relative movement of the pinion shaft and the inner ring in the axial direction,
The minimum steering inner diameter of the said control part is made larger than the outer diameter of an annular member, The steering apparatus for vehicles characterized by the above-mentioned   4. The vehicle steering apparatus according to claim 2, wherein an escape portion for preventing interference with the upper end of the inner ring is provided in the restriction portion.   2. The vehicle steering apparatus according to claim 1, wherein a minimum inner diameter of the restricting portion is larger than an outer diameter of the inner ring and smaller than an inner diameter of the outer ring. 6. An annular seal member according to claim 1, wherein the annular seal member is held on the inner periphery of the main body of the screw member and seals between the inner periphery of the main body of the screw member and the outer periphery of the pinion shaft. With
The vehicle steering apparatus, wherein the restriction member restricts the downward movement of the seal member in the axial direction.

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