JP2008265590A - Rack and pinion steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rack and pinion steering device in which abnormal noise is surely prevented from occurring when a bush for holding a rack shaft is held on a housing. <P>SOLUTION: This rack and pinion steering device comprises at least a pinion to which a steering force input from a steering wheel 1 is transmitted, the rack shaft 22 having a rack 22a screwed with the pinion, and the housing 21 in which the pinion and the rack shaft 22 are installed. The rack shaft 22 is axially slidably held by the bushes 23 for holding the rack shaft disposed at both ends of the housing 21. The bush 23 for holding the rack shaft comprises, on the outer peripheral surface, a fitting projecting part 23b fitted to the fitting recessed part 21b formed in the housing 21. The axial length of the fitting projecting part 23b is longer than the axial length of the fitting recessed part 21b of the housing 21. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rack and pinion type including at least a pinion to which a steering force inputted from a steering wheel is transmitted, a rack shaft having a rack screwed to the pinion, and a housing that houses the pinion and the rack shaft. The present invention relates to a steering device.

As this type of rack and pinion type steering device, for example, between the gear case and the rack shaft to slidably support the rack shaft on the gear case, the outer peripheral surface abuts on the inner peripheral surface of the gear case in the circumferential direction. Regions and regions that do not abut against the inner peripheral surface of the gear case and that form air flow gaps between the gear case and the regions that form the air flow gaps partially. A bush that extends in the axial direction and has a protrusion that contacts the inner peripheral surface of the gear case is interposed, and this bush forms a protrusion on the outer peripheral surface of one end in the axial direction on the gear case. A configuration is known in which positioning in the axial direction and the circumferential direction is performed by engaging with the formed holes (see, for example, Patent Document 1).
Japanese Utility Model Laid-Open No. 4-135875 (first page, FIGS. 1 and 3)

  However, in the conventional example described in Patent Document 1, positioning of the bush with respect to the gear case is performed by engaging a protrusion formed on the outer peripheral surface of the bush with a hole formed in the gear case. In order to facilitate the engagement of both, when engaging the protrusions provided on the outer peripheral surface of the bush and the hole formed in the gear case, there must be a gap between them, When steering the steering wheel, friction is generated between the rack shaft and the bush. Therefore, the bush also moves with the movement of the rack shaft, generating abnormal noise and increasing the amount of wear of the bush. There is an unresolved issue.

  That is, the normal bush is formed of an elastic material such as a synthetic resin material, and as shown in FIG. 11, on the outer peripheral surface of one axial end portion, that is, the left end portion of the cylindrical bush 100, on the right end portion. A protrusion 102 having a tapered surface 101 whose axial length becomes shorter as going outward is formed, and this protrusion 102 has the same shape as the protrusion 102 formed on the housing 103 constituting the rack and pinion gear mechanism. The bush 100 is mounted on the housing 103 in a state where movement in both the axial direction and the circumferential direction is restricted, and the rack shaft 105 is slidably held on the inner peripheral surface of the bush 100. Like to do.

  When the projecting portion 102 of the bush 100 is engaged with the engaging recess 104 of the housing 103 and the gap 106 exists in the axial direction as shown in FIG. Since the rack shaft 105 is in sliding contact with the inner peripheral surface of the bush 100, when the rack shaft 105 is moved during steering, the friction force Ff between the rack shaft 105 and the inner peripheral surface of the bush 100 causes the bush 100 also moves with the movement of the rack shaft 105, and the axial end surface of the protrusion 102 of the bush 100 abuts against the axial inner surface of the engagement recess 104 of the housing 103, and generates an abnormal noise that becomes an impact sound. To do.

  In order to prevent the generation of this abnormal noise, the projections 102 of the bush 100 and the engagement recesses 104 of the housing are matched with each other, and the shafts of both the shafts are engaged with each other. Although it is conceivable that no gap is generated between the direction facing surfaces, even in this case, the rack shaft 105 moves and the rack 100 is moved because the bush 100 is formed of an elastic body such as a synthetic resin material. When an axial movement force is transmitted to the bush 100 by the frictional force Ff between the shaft 105 and the inner peripheral surface of the bush 100, the contact surface on the side that contacts the axial end surface of the engaging recess 104 in the protrusion 102 of the bush 100. Due to the elastic deformation, a gap is generated between the axial end surface opposite to the contact surface of the protrusion 102 and the opposed inner end surface of the engagement recess 104, and the rack shaft 105 is moved. When the direction is reversed, the end surface of the protrusion 102 is eliminated gap is to emit abnormal sound collides with the inner end surface of the engagement recess 104.

  Accordingly, the present invention has been made paying attention to the unsolved problems of the above-described conventional example, and a rack that can reliably prevent the generation of abnormal noise when the rack shaft holding bush is held in the housing. -It aims at providing a pinion type steering device.

In order to achieve the above object, a rack and pinion type steering apparatus according to claim 1 is provided with a pinion to which a steering force inputted from a steering wheel is transmitted, a rack shaft having a rack screwed to the pinion, and A rack and pinion type steering device comprising at least a pinion and a housing that houses a rack shaft,
The rack shaft is slidably held in the axial direction by a rack shaft holding bush disposed at an end of the housing, and the rack shaft holding bush is formed in a fitting recess formed in the housing on an outer peripheral surface. It has a fitting convex part to be fitted, and the axial length of the fitting convex part is set longer than the axial length of the fitting concave part of the housing.

Further, in the rack and pinion type steering device according to claim 2, in the invention according to claim 1, the fitting convex portion is gradually in the axial direction as one end surface in the axial direction goes outward from the outer peripheral surface. The inclined surface has a shorter length, and the axial length at the outer peripheral surface position of the fitting convex portion is set longer than the axial length of the fitting concave portion of the housing.
Furthermore, the rack and pinion type steering apparatus according to claim 3 is characterized in that, in the invention according to claim 2, the inclined surface is composed of a plurality of ribs arranged in parallel in the circumferential direction.

  Furthermore, the rack and pinion type steering device according to claim 4 is the invention according to any one of claims 1 to 3, wherein the rack shaft holding bush has serrations formed on an outer peripheral surface contacting the housing. It is characterized by being.

  According to the present invention, since the axial length of the fitting convex portion of the rack shaft holding bush is set longer than the axial length of the fitting concave portion of the housing, the fitting convex portion of the rack shaft holding bush is When fitted into the fitting recess of the housing, there is a tightening margin, and the axial movement force acts on the rack shaft holding bush by the movement of the rack shaft during steering, and the fitting recess of the fitting convex portion Even when the contact surface is elastically deformed, it is possible to reliably prevent a gap from occurring in the axially opposed surface between the fitting convex portion and the fitting concave portion, and the axial end surfaces of the fitting convex portion face each other. There is an effect that it is possible to surely prevent the generation of abnormal noise by contacting the axial end surface of the fitting recess.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 is an overall configuration diagram showing an embodiment of the present invention, FIG. 2 is a front view showing a partially enlarged steering gear mechanism, FIG. 3 is a perspective view showing a rack shaft holding bush, and FIG. 4 is a rack. It is a figure which shows the bush for an axis | shaft, Comprising: (a) is a longitudinal cross-sectional view, (b) is a right view.
In FIG. 1, reference numeral 2 denotes a steering shaft having a steering wheel 1 mounted on the vehicle rear end (right end in FIG. 1). The steering shaft 2 is rotatably held by a steering column 3. On the vehicle front end (left end in FIG. 1) side of the steering shaft 2, a worm speed reducer 11 that applies steering assist torque to the steering shaft 2 and an electric motor 12 that generates steering assist torque in the worm speed reducer 11 are configured. The steering assist mechanism 4 is connected.

An intermediate shaft 18 is connected to the output shaft 14 of the worm reducer 11 via a universal joint 17A, and this intermediate shaft 18 is connected to a pinion shaft 19 of a rack and pinion type steering gear mechanism 6 via a universal joint 17B. Has been.
A rack shaft (not shown) of the steering gear mechanism 6 is connected to a steered wheel (not shown) via a tie rod 5.

  Here, the steering shaft 2 includes an outer shaft 7 and an inner shaft 8, and the front end portion of the outer shaft 7 and the rear end portion of the inner shaft 8 are spline-coupled and are coupled via a synthetic resin pin 8a. ing. Therefore, the outer shaft 7 and the inner shaft 8 can shorten the total length by breaking the synthetic resin pin 8a at the time of collision.

Further, the cylindrical steering column 3 inserted through the steering shaft 2 is formed by combining an outer column 9 and an inner column 10 in a telescope shape, and this impact is applied when an impact is applied in the axial direction toward the vehicle front side. This is a so-called collapsible structure that reduces the overall length while absorbing energy.
The front end portion of the inner column 10 is fixed to the rear end surface of the housing 11a of the worm reducer 11, the inner shaft 8 is inserted into the housing 11a of the worm reducer 11, and the front end portion of the inner shaft 8 is connected to the worm reducer. The speed reducer 11 is connected to an output shaft 14 protruding from the front end surface of the housing 11a.

  The outer column 9 of the steering column 3 is supported on the vehicle body side member 16 by the upper bracket 15U so that the tilt and telescopic position can be adjusted, and the housing 11a of the worm speed reducer 11 in the steering assist mechanism 4 is attached to the vehicle body side member 16. A pivot pin 15p pivotally supported by the attached lower bracket 15L is supported so as to be swingable in the vertical direction.

  As shown in FIG. 2, the steering gear mechanism 6 includes a pinion (not shown) connected to the pinion shaft 19 and a rack shaft 22 having a rack 22a meshing with the pinion in the gear housing 21. The rotary motion transmitted to the pinion shaft 19 is converted into a straight motion by the rack shaft 22. Here, as shown in FIG. 2, the rack shaft 22 is slid in the axial direction by a rack shaft holding bush 23 disposed near the right end of the gear housing 21 on the opposite side of the pinion shaft 19 in the axial direction. It is held freely. The tie rod 5 is connected to both ends of the rack shaft 22 via ball joints 24.

  The rack shaft holding bush 23 for holding the rack shaft 22 is formed, for example, by injection molding a synthetic resin material having elasticity. As shown in FIGS. 2 to 4, the rack shaft 22 is slidably contacted with the inner peripheral surface. The cylindrical part 23a to hold | maintain and the rectangular parallelepiped fitting convex part 23b which protrudes outward formed in three places of the circumferential direction in the outer peripheral surface of the one end side of this cylindrical part 23a are comprised. And the cylindrical part 23a and the fitting convex part 23b of this bush 23 for rack shaft holding | maintenance are expanded and illustrated in FIG. 2, the cylindrical accommodating part 21a formed in the internal peripheral surface of the gear housing 21, and 3 of the circumferential direction Each is fitted into a fitting recess 21b formed at a location.

  Here, as shown in FIGS. 4A and 4B, the fitting convex portion 23b of the rack shaft holding bush 23 has an axial end surface and a circumferential end surface formed on vertical surfaces, respectively. The axial length C between the surfaces is set to be longer than the axial length D of the fitting recess 21b formed on the inner peripheral surface of the gear housing 21 shown enlarged in FIG. However, the axial length C of the fitting convex portion 23b is not as long as it is longer than the axial length D of the fitting concave portion 21b, and when fitting the fitting convex portion 23b to the fitting concave portion 21b, The length is set in consideration of the elastic deformation allowance of the fitting convex portion 23b so that the fitting convex portion 23b can be fitted into the fitting concave portion 21b by compressing and elastically deforming the fitting convex portion 23b. Further, the circumferential length of the fitting concave portion 21b may be substantially equal to the circumferential length of the fitting convex portion 23b, but slightly longer than the circumferential length of the fitting convex portion 23b. Thus, it is preferable that the increase in length in the circumferential direction when the fitting convex portion 23b is compressed in the axial direction can be absorbed.

Next, the operation of the first embodiment will be described.
First, in order to assemble the steering gear mechanism 6, first, the rack shaft from the end face side of the gear housing 21 is mounted without the pinion (not shown) formed on the pinion shaft 19 or the rack shaft 22 being mounted on the gear housing 21. The holding bush 23 is inserted from the axial end surface side where the fitting convex portion 23b of the cylindrical portion 23a is not formed, and the cylindrical portion 23a is fitted into the cylindrical housing portion 21a formed on the inner peripheral surface of the gear housing 21. Then, the outer peripheral surface of the fitting convex portion 23b is inserted in a compressed state using a predetermined jig. Thereafter, the fitting projection 23b is fitted with the fitting projection 23b by elastically extending the fitting projection 23b by removing the jig with the fitting projection 23b and the fitting recess 21b of the gear housing 21 substantially overlapping. Fit into the mating recess 21b. In this state, the fitting convex portion 23b is compressed in the axial direction by pressing the end surface of the rack shaft holding bush 23 on the fitting convex portion 23b side with a jig such as a round bar having a vertical end surface. The rear end surface of the convex portion 23b is fitted into the fitting concave portion 21b.

As described above, the rack shaft holding bush 23 in which the axial length C of the fitting convex portion 23b is set to be longer than the axial length D of the fitting concave portion 21b is attached to the gear housing 21, thereby holding the rack shaft. The fitting projection 23b of the bush 23 is fitted into the fitting recess 21b formed on the inner peripheral surface of the gear housing 21 with a margin in the axial direction.
Thereafter, with one of the sockets 24a constituting the ball joint 24 connected to the tie rods 5 disposed at both ends of the rack shaft 22 removed, the socket shaft 23 is inserted into the inner peripheral surface of the cylindrical portion 23a of the rack shaft holding bush 23. The rack 24 is then slidably held by the gear housing 21 via the rack shaft holding bush 23 by attaching the socket 24b removed after sliding to the rack shaft 22, and this rack shaft. The tie rod 5 is coupled to the ball 22 via the ball joint 24.

Next, a pinion (not shown) formed on the pinion shaft 19 is attached to the gear housing 21 and engaged with the rack 22 a of the rack shaft 22. Then, by connecting the pinion shaft 19 to the intermediate shaft 18 to which the steering column 3 and the steering assist mechanism 4 are connected via the universal joint 17B, a rack and pinion type steering device is configured.
In this state, by steering the steering wheel 1, the steering torque transmitted to the steering wheel 1 is transmitted to the steering assist mechanism 4 via the steering shaft 2, and the steering torque disposed in the steering assist mechanism 4. A steering torque is detected by a sensor (not shown), and a steering assist current command value is calculated by a control device (not shown) based on the steering torque and a vehicle speed detected by a vehicle speed sensor (not shown). When the electric motor 12 is driven and controlled based on the steering assist current command value, the electric motor 12 generates a steering assist torque corresponding to the steering torque. The steering assist torque generated by the electric motor 12 is decelerated by the worm reducer 11 and transmitted to the steering shaft 2.

Since the steering torque and steering assist torque transmitted to the steering shaft 2 are transmitted to the pinion shaft 19 of the steering gear mechanism 6 via the intermediate shaft 18, a pinion formed on the pinion shaft 19 (not shown) 2 is moved in the axial direction in FIG. 2.
When the rack shaft 22 moves in the axial direction in this way, the tie rod 5 connected to the rack shaft 22 via the ball joint 24 also moves in the axial direction, and a steered wheel (not shown) rotates accordingly. The vehicle is turned and steered.

  At this time, when the rack shaft 22 moves in the axial direction, the rack shaft 22 is slidably held on the inner peripheral surface of the cylindrical portion 23a of the rack shaft holding bush 23. The load for moving the rack shaft 22 is also transmitted to the rack shaft holding bush 23 by the frictional force between the shaft holding bush 23 and the inner peripheral surface of the cylindrical portion 23a, so that the rack shaft holding bush 23 is also fitted into the projection. It moves in the axial direction by the elastic deformation of 23a. However, since the fitting convex portion 23b of the rack shaft holding bush 23 is fitted to the fitting concave portion 21b formed on the inner peripheral surface of the gear housing 21 with an interference in the axial direction, the rack shaft holding bush Even if the fitting convex portion 23b of the bush 23 moves in the axial direction and the end surface side contacting the fitting concave portion 21b is elastically deformed, the compression load is released slightly on the opposite end surface in the axial direction of the fitting concave portion 21b. Thus, the contact state with the end face of the fitting recess 21b is maintained, and a gap is prevented from being generated between the end face of the fitting protrusion 23b and the end face of the fitting recess 21b.

  Therefore, when the steering wheel 1 is steered in the reverse direction and the steering torque and the steering assist torque are transmitted to the pinion shaft 19 and the rack shaft 22 starts moving in the reverse direction, Since the end surface on the moving side of the fitting convex portion 23b of the bush 23 is in contact with the end surface of the fitting concave portion 21b, it is possible to reliably prevent the generation of abnormal noise as an impact sound.

  In the above embodiment, the case where both end surfaces of the rack shaft holding bush 23 in the axial direction are both vertical surfaces orthogonal to the axial direction has been described. However, the present invention is not limited to this. As shown in FIGS. 5A and 5B showing a perspective view and a longitudinal sectional view of the bush, a triangular pyramid-shaped rib 30 is formed on one end face in the axial direction of the fitting convex portion 23b of the rack shaft holding bush 23. A plurality of, for example, two are formed at a predetermined interval in the circumferential direction so that the axial length of the fitting convex portion 23b gradually decreases from the outer peripheral surface side of the cylindrical portion 23a to the outside. The axial length E including the fitting convex portion 23b and the rib 30 on the outer peripheral surface of the cylindrical portion 23a is set to be longer than the axial length D of the fitting concave portion 21b formed in the gear housing 21 described above. You can do . In this case, the same operational effects as those of the above-described embodiment can be obtained, and the axial length F at the top position of the rib 30 is substantially equal to or slightly equal to the axial length D of the fitting recess 21b. By setting it short, the fitting convex part 23b can be easily fitted to the fitting concave part 21b. The rib 30 is not limited to a triangular pyramid shape, and may be formed in a wedge shape having a flat inclined surface on the axial end surface side.

  Further, as shown in FIGS. 6A and 6B showing a perspective view and a longitudinal sectional view of the rack shaft holding bush, one end face of the axial end faces of the fitting convex portion 23b instead of the rib 30 is used. Alternatively, the inclined surface 31 having the inclination angle θ0 may be formed so that the axial length of the fitting convex portion 23b gradually decreases as going outward from the outer peripheral surface of the cylindrical portion 23a. In this case as well, as in the case of the rib 30 described above, the axial length E of the fitting protrusion 23b on the outer peripheral surface of the cylindrical portion 23a is the axis of the fitting recess 21b formed on the inner peripheral surface of the gear housing 21. By making it longer than the direction length D, it is possible to obtain the same effect as that of the embodiment described above, and the axial length F at the outer end of the fitting convex portion 23b is set to the axial direction of the fitting concave portion 21b. By setting the length D substantially equal to or slightly shorter than the length D, the fitting convex portion 23b can be easily fitted into the fitting concave portion 21b.

  Moreover, although the said embodiment demonstrated the case where the three fitting convex parts 23b were formed in the cylindrical part 23a of the bush 23 for rack shaft holding | maintenance, it is not limited to this, Arbitrary number formation is carried out in the circumferential direction. Further, as shown in FIGS. 7 (a) and 7 (b) showing a perspective view and a longitudinal sectional view of the rack shaft holding bush, the fitting convex portion 23b is formed in an annular shape. A desired number of triangular pyramid-shaped ribs 40 are formed on one of the axial end surfaces of the fitting convex portion 23b, and the fitting concave portion 21b formed on the inner peripheral surface of the gear housing 21 according to this is also annular. You may make it comprise as a groove | channel. In this case, since the fitting convex portion 23b is annular, the rigidity can be increased, and the axial rigidity when fitted with the fitting concave portion 21b can be increased by increasing the number of ribs to be formed. Can be improved.

  Further, in the above embodiment, the case where the cross-sectional shape of the fitting recess 21b formed in the gear housing 21 is rectangular has been described, but the present invention is not limited to this, and the fitting protrusion of the rack shaft holding bush 23 is not limited thereto. As shown in FIG. 8 showing the relationship between the portion 23b and the fitting recess 21b of the gear housing 21, the inclined surface whose axial length gradually decreases as the axial end faces go from the inner peripheral surface to the outer peripheral surface, respectively. 45a and 45b, the inclination angle θ1 of one inclined surface 45a may be smaller than the inclination angle θ2 of the other inclined surface 45b, and the cross-sectional shape may be trapezoidal. In this case, the fitting convex part 23b of the rack shaft holding bush 23 also has an axial end face on the inclined surface 45a side having a small inclination angle of the fitting concave part 21b as the inclined surface 46 having the inclination angle θ3, and the fitting convex part 23b is cylindrical. The axial length at the outer peripheral surface of the portion 23a is G, the axial length at the outer end is H, the axial length at the inner peripheral surface of the fitting recess 21b is D, and the axial length at the bottom side By setting H <D <G and θ1> θ3 when the thickness is I, it is possible to obtain the same operation and effect as in the above embodiment, and the fitting convex portion 23b to the fitting concave portion 21b. The fitting can be performed more easily. Here, by setting H ≧ I, the rigidity of the fitting protrusion 23b can be further improved.

  Furthermore, in the above-described embodiment, the case where the cylindrical portion 23a of the rack shaft holding bush 23 has a cylindrical outer peripheral surface has been described. However, the present invention is not limited to this and represents a perspective view of the rack shaft holding bush. As shown in FIG. 9, you may make it form the serration 50 in the outer peripheral surface of the cylindrical part 23a. In this case, the contact area between the cylindrical portion 23a and the inner peripheral surface of the cylindrical housing portion 21a of the gear housing 21 can be reduced, and the mounting work for mounting the rack shaft holding bush 23 to the cylindrical housing portion 21a is easy. Can be done. Thus, even if the serration 50 is formed on the outer peripheral surface of the cylindrical portion 23a to reduce the contact area with the cylindrical storage portion 21a, the rack shaft holding bush 23 is not moved when the rack shaft 22 moves in the axial direction as described above. Since it hardly slides in the axial direction, wear on the outer peripheral surface of the cylindrical portion 23 a can be suppressed, and the life of the rack shaft holding bush 23 formed with the serrations 50 can be prolonged.

  Furthermore, in the above-described embodiment, the case where the gear housing 21 is formed by the small-diameter portion at the intermediate portion and the large-diameter portions at both end portions has been described. However, the present invention is not limited to this. As shown in FIG. 10 showing a partial appearance, the gear housing 21 may be formed in a cylindrical pipe shape, and the fitting hole 51 penetrating the gear housing 21 may be used as a fitting recess 21b.

Moreover, in the said embodiment, although the case where the inclination part which consists of a rib or an inclined surface was provided in the inner end surface of the fitting convex part 23b formed in the bush 23 for rack shaft holding | maintenance was demonstrated, it is not limited to this Alternatively, the outer end face may be provided with an inclined portion made of a rib or an inclined surface, and an inclined portion made of a rib or an inclined surface may be provided on both sides in the axial direction.
Furthermore, in the above embodiment, the case where the rack shaft holding bush 23 is disposed on the right end side of the gear housing 21 opposite to the pinion shaft 19 side has been described, but the present invention is not limited to this. A rack shaft holding bush 23 may also be provided on the left end side of the housing 21.

It is a whole lineblock diagram showing one embodiment of the present invention. FIG. 2 is a front view showing a part of the steering gear mechanism of FIG. 1 in an enlarged manner. It is a perspective view which shows the bush for rack shaft holding | maintenance. It is a figure which shows the bush for rack shaft holding | maintenance, Comprising: (a) is a longitudinal cross-sectional view, (b) is a right view. It is a figure which shows the modification of the bush for rack shaft holding | maintenance, Comprising: (a) is a perspective view, (b) is a longitudinal cross-sectional view. It is a figure which shows the other modification of the bush for rack shaft holding | maintenance, Comprising: (a) is a perspective view, (b) is a longitudinal cross-sectional view. It is a perspective view which shows the other modification of the bush for rack shaft holding | maintenance. It is a figure which shows the relationship between the fitting protrusion of the bush for rack shaft holding | maintenance, and the fitting recessed part of a gear housing. FIG. 10 is a perspective view showing still another modification of the rack shaft holding bush. It is a perspective view which shows the other example of a gear housing. It is a figure which shows the relationship between the gear housing of a prior art example, and the bush for rack shaft holding | maintenance.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Steering wheel, 2 ... Steering shaft, 3 ... Steering column, 4 ... Steering assist mechanism, 5 ... Tie rod, 6 ... Steering gear mechanism, 17A, 17B ... Universal joint, 18 ... Intermediate shaft, 19 ... Pinion shaft, 21 ... Gear housing, 21a ... Cylinder housing, 21b ... Fitting recess, 22 ... Rack shaft, 22a ... Rack, 23 ... Rack shaft holding bush, 23a ... Cylinder, 23b ... Fitting projection, 30 ... Rib, 31 ... Inclined surface, 40 ... rib, 45a, 45b ... inclined surface, 46 ... inclined surface, 50 ... serration, 51 ... fitting hole

Claims (4)

A rack and pinion type steering apparatus comprising at least a pinion to which a steering force input from a steering wheel is transmitted, a rack shaft having a rack screwed to the pinion, and a housing that houses the pinion and the rack shaft. And
The rack shaft is slidably held in the axial direction by a rack shaft holding bush disposed at an end of the housing, and the rack shaft holding bush is formed in a fitting recess formed in the housing on an outer peripheral surface. A rack-and-pinion type steering device having a fitting convex portion to be fitted, wherein the axial length of the fitting convex portion is set longer than the axial length of the fitting concave portion of the housing.   The fitting convex portion is an inclined surface whose axial length gradually decreases as one end face in the axial direction goes outward from the outer circumferential surface, and the axial direction at the outer circumferential surface position of the fitting convex portion The rack and pinion type steering device according to claim 1, wherein the length is set longer than the axial length of the fitting recess of the housing.   The rack and pinion type steering device according to claim 2, wherein the inclined surface is constituted by a plurality of ribs arranged in parallel in the circumferential direction.   The rack and pinion type steering device according to any one of claims 1 to 3, wherein the rack shaft holding bush has serrations formed on an outer peripheral surface thereof which contacts the housing.

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