JP2003072561A - Rack pinion steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To guide the movement of a rack shaft stably for a long period of time by reducing a possibility of damaging a loading state of a rack receiving sheet on a rack guide. SOLUTION: A locking hole 33, and locking grooves 34, 34 are formed at a bottom surface of a recessed groove 31, which is provided at a tip end of the rack guide 3 and corresponds to a shape of a back surface of the rack shaft, and at both side surfaces of the recessed groove 31, respectively. A locking projection 42 corresponding to the locking hole 33 and locking projections 43, 43 corresponding to the locking grooves 34, 34 are formed at a surface of the rack receiving sheet 4 facing to the rack guide 3 and the locking projection 42, and locking projections 43, 43 are engaged with the locking hole 33 and with the locking grooves 34, 34, respectively to mount the rack receiving sheet 4 on the rack guide 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rack and pinion type steering device which is widely used as one type of steering device for automobiles.

[0002]

2. Description of the Related Art A rack and pinion type steering device supports a rack shaft inside a rack housing extending in the left-right direction of a vehicle body so as to be movable in the axial length direction, and the shaft is provided in the middle of the rack housing. A pinion shaft is supported rotatably around an axis in a pinion housing that is continuously arranged with its cores crossed, and a pinion integrally formed on the pinion shaft has an appropriate length on a part of the peripheral surface of the rack shaft. The pinion shaft protruding from the pinion housing is connected to the left and right steering wheels (generally the front wheels) while being engaged with the rack teeth formed over the entire length of the rack housing. Is connected to a steering wheel, and the rotation of the pinion shaft caused by the operation of the steering wheel is converted into a movement in the axial direction of the rack shaft so that it is connected to both ends of the rack shaft. And it has a configuration allowed to steering the left and right steering wheels that are.

In such a rack and pinion type steering device, the rack teeth formed on the rack shaft and the pinion shaft are integrally formed in order to carry out steering in both left and right directions with high accuracy without delay. It is important to apply an appropriate preload to the meshing part with the pinion and mesh them with each other substantially without backlash. For this reason, conventionally, a rack guide has been used that presses the peripheral surface of the rack shaft from the side opposite to the meshing portion with the pinion and moves and guides the rack shaft while applying a preload to the meshing portion.

FIG. 6 is a vertical cross-sectional view of a main part of a conventional rack and pinion type steering device. As shown in the figure, the pinion shaft 2 integrally formed with the pinion 20 in the lower half portion is coaxially rotatable inside the pinion housing H ₂ by a pair of ball bearings 21 and 22 on both sides of the pinion 20. Supported by
The protruding end of the pinion shaft 2 to the upper part of the pinion housing H ₂ is connected to a steering wheel (steering wheel) S schematically shown in the drawing.

A cylindrical rack housing H ₁ is connected to the middle of the pinion housing H ₂ . A rack shaft 1 is supported inside the rack housing H ₁ so as to be movable in the axial direction, and the rack shaft 1 has a rack tooth 10 formed on one side thereof over a suitable length. It is meshed with the pinion 20. Both ends of the rack shaft 1 projecting to both sides of the rack housing H ₁ are connected to left and right steering wheels (not shown).

A guide housing H ₃ is provided on the opposite side of the intersection of the rack housing H _{1 and} the pinion housing H _{2 in} a direction substantially orthogonal to these, and inside the guide housing H ₃ , A cylindrical rack guide 3 is slidably fitted inside. The rack guide 3 is a support cap fixed to the opening of the guide housing H _3.
A back side of the rack shaft 1 (opposite of the pinion 20 and the meshing portion) is pressed and urged toward the rack shaft 1 by a push spring 26 interposed between the rack shaft 1 and the rack support sheet 4 mounted on the front end thereof. Side).

In the illustrated rack and pinion type steering device, a protrusion 11 having an appropriate width is provided on the back surface of the rack shaft 1 over the entire length of the area where the rack teeth 10 are formed. A groove 31 for receiving the protrusion 11 is formed at the tip.

With the above configuration, the steering wheel S for steering
Is operated, the pinion shaft 2 connected to the steering wheel S rotates, and this rotation is converted into movement of the rack shaft 1 in the axial direction at the meshing portion between the pinion 20 and the rack tooth 10. This movement is transmitted to the left and right steering wheels for steering. At this time, the rack guide 3 is attached to the rack shaft 1.
The pinion shaft 2 against the rack teeth 10 and pinion
While exerting a preload on the meshing portion with 20, the guide action guides the movement of the rack shaft 1 in the axial direction.

During the above steering operation, for example, the rotation of the rack shaft 1 about the axis generated by the force applied to the meshing portion of the rack teeth 10 and the bending of the rack shaft 1 generated by the acting force from the steering wheel. An unnecessary operation of the rack shaft 1 other than movement in the axial direction, such as displacement, may occur. Such an operation is suppressed by the protrusion 11 provided on the back surface of the rack shaft 1 coming into contact with the side surface of the groove 31 provided on the rack guide 3 via the rack receiving sheet 4.

[0010]

Now, in the rack and pinion type steering device configured as described above, the rack shaft 1
The rack receiving sheet 4 interposed between the rear surface of the rack and the rack guide 3 reduces the sliding resistance of the rack shaft 1 under the pressure of the rack guide 3 and allows the rack shaft 1 to move smoothly. It acts.

FIG. 7 is an explanatory view showing how the rack receiving sheet 4 is attached to the rack guide 3. A concave groove 31 for receiving the protrusion 11 on the back surface of the rack shaft 1 is formed at the tip (upper end of the figure) of the rack guide 3 having a cylindrical shape as shown in the drawing so as to cross the central portion. Both sides of 31 are tapered receiving surfaces 32, 32 that widen toward the tip, and a recess 30 having a Y-shaped cross section corresponding to the back surface shape of the rack shaft 1 including the protrusion 11 is formed. ing. In such a rack guide 3, a mounting hole 33 having a circular cross section is formed so as to penetrate the shaft center portion and open to the approximate center of the bottom surface of the concave groove 31 for mounting the rack receiving sheet 4.

The rack receiving sheet 4 can be fitted into the groove 31 of the rack guide 3 by bending a thin sheet material in which a resin coating 4b is applied to one surface of a metal base 4a. Receiving portion 40 having a rectangular cross section having a large outer width and an inner width capable of receiving the protrusion 11 of the rack shaft 1, and the receiving portions 32, 32 of the rack guide 3 which are continuously provided on both sides of the receiving portion 40. Correspondingly, it is provided with sliding portions 41, 41 that expand in a tapered shape. Such a rack receiving sheet 4 is provided with a bottomed cylindrical locking projection 42 at the center of the outer surface of the receiving portion 40 for mounting on the rack guide 3.

Rack receiving sheet 4 constructed as described above
The base material 4a side is opposed to the concave portion 30 at the front end of the rack guide 3, and as shown by the arrow in FIG.
The receiving portion 40 of the rack guide 3 is fitted into the concave groove 31 of the rack guide 3, and the locking projections 42 projecting from the receiving portion 40 are press-fitted into the locking holes 33 opening at the bottom surface of the concave groove 31 to be mounted. , The rack receiving sheet 4 thus mounted is provided with the rack guide 3
By the above-mentioned assembly, the rack shaft 1 is brought into contact with the back surface of the rack shaft 1, and the rack shaft 1 moves in the axial direction with sliding on the sliding portions 41.

However, during this movement, the sliding portions 41,
Sliding resistance of the back surface of the rack shaft 1 is added to 41, and this sliding resistance is concentrated on the locking projections 42 and a shearing force is applied to the root of the locking projections 42, resulting in a large number of steering operations. There is a possibility that the locking projection 42 may be damaged by the repetition of the operation,
The mounting state of the rack receiving seat 4 is damaged and the rack shaft 1
However, there is a problem in that it is not possible to stably guide the movement of the vehicle and the steering feeling is deteriorated.

As described above, the sliding surface of the rack shaft 1 is covered with the resin coating 4b. By properly selecting the coating 4b, the sliding resistance can be kept at a low level to alleviate the above-mentioned problems. Is possible. However, it is unavoidable that a part of the coating 4b is peeled off due to repeated sliding contact of the rack shaft 1 and the sliding resistance between the rack shaft 1 and the rack shaft 1 is increased with time, and the locking due to the action of the shearing force Under the present circumstances, it is difficult to stably guide the movement of the rack shaft 1 for a long period of time because the protrusion 42 is damaged.

The present invention has been made in view of these circumstances, and the sliding resistance between the rack shaft and the rack shaft impairs the mounting state of the rack receiving sheet slidingly contacting the rack shaft on the rack guide. The fear can be greatly reduced and the movement guide of the rack shaft can be stably performed for a long period of time.
An object of the present invention is to provide a rack and pinion type steering device that can obtain a good steering feeling.

[0017]

A rack and pinion type steering device according to a first aspect of the present invention includes a rack shaft having a protrusion extending in the axial direction on the back surface of a meshing portion with a pinion, and The rack receiving sheet includes a rack guide including a concave groove for receiving a ridge and having a concave portion corresponding to the rear surface of the rack shaft, and a rack receiving sheet mounted in the concave portion and abutting against the rear surface of the rack shaft. A rack and pinion steering device configured to move and guide the rack shaft while applying a preload to a meshing portion with the pinion by the rack guide that presses the rack shaft from the rear side via
The rack guide includes locking holes formed on the bottom surface of the concave groove and locking grooves formed on both side surfaces of the concave groove, and the rack receiving sheet is provided on a surface facing the concave portion. A locking projection corresponding to each of the locking hole and the locking groove is provided, and the locking projection is engaged with the locking hole and the locking groove and mounted on the rack guide. To do.

According to the present invention, a locking hole having an opening on the bottom surface of the concave groove formed in the rack guide for receiving the protrusion provided on the back surface of the rack shaft, and a locking groove formed on both side surfaces of the concave groove. The rack receiving sheet is formed by engaging the locking projections formed on the rack receiving sheet with the locking holes and the locking grooves separately, and the sliding resistance between the rack receiving sheet and the rack shaft is adjusted. The locking projections are allotted to each to prevent damage to each locking projection.

Further, in the rack and pinion type steering device according to the second aspect of the present invention, the rack receiving sheet according to the first aspect of the present invention has a resin coating film on the surface of the metal base material which is in contact with the rack shaft. It is characterized by being formed.

In the present invention, a resin coating is formed on one surface of a metal base material, and the rack receiving is performed by a two-layer sheet material having both high strength of metal material and slidability of resin material. A seat is formed, and the surface on which the resin coating is formed is pressed against the rack shaft to reduce the initial sliding resistance and prevent the mounting state of the rack receiving sheet from being impaired.

Further, in the rack and pinion type steering device according to the third invention of the present invention, the locking groove in the first or second invention is
It is characterized in that it is formed as a tapered groove whose depth decreases toward the bottom of the groove.

In the present invention, the locking grooves formed on both side surfaces of the recessed groove of the rack guide are tapered grooves that reduce the depth toward the bottom of the recessed groove, and are projected at corresponding portions of the rack receiving sheet. The engagement with the locking projection is facilitated.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the drawings showing the embodiments thereof. FIG. 1 is a vertical cross-sectional view showing a configuration of a main part of a rack and pinion steering device (hereinafter referred to as the device of the present invention) according to the present invention.

In the figure, H ₂ is a pinion housing, and the pinion shaft 2 is arranged inside the pinion housing H ₂ . The pinion shaft 2 is provided with a pinion 20 integrally formed by expanding the lower half portion, and a pair of angular ball bearings 21 and 22 located on both upper and lower sides of the pinion 20 allow the pinion shaft 2 to be housed inside the pinion housing H ₂ . It is rotatably supported on the same axis. Further, the upper end portion of the pinion shaft 2 protruding to the outside of the pinion housing H ₂ is connected to a steering wheel (steering wheel) S schematically shown in the drawing. Thus, the pinion shaft 2 rotates inside the pinion housing H ₂ in accordance with the rotating operation of the steering wheel S for steering.

[0025] one side of the lower half portion of the pinion housing H ₂ is the rack housing H ₁ having a cylindrical shape are continuously provided by crossing the axis, the interior of the rack housing H _1, the shaft The rack shaft 1 is supported so as to be movable in the longitudinal direction. On the peripheral surface of the rack shaft 1, the pinion housing H
Rack teeth 10 are formed on the side facing the communicating portion with ₂ over an appropriate length, and the rack teeth 10 are meshed with the pinion 20. Both ends of the rack shaft 1 are projectingly provided on both sides of the rack housing H ₁ and are respectively connected to left and right steering wheels (not shown). These steering wheels are connected to the rack shaft 1 in the rack housing H ₁ . It is designed to be steered according to the movement of the.

On the back side of the rack shaft 1 (opposite side of the pinion 20 and the meshing portion), a pair of taper surfaces inclined in opposite directions to each other.
12, 12 (see FIG. 2) are provided, and a ridge 11 having an appropriate width centered on the intersection of these tapered surfaces extends over substantially the entire length of the formation region of the rack teeth 10. The front end of the rack guide 3 is brought into contact with the back surface of the rack shaft 1 through the rack receiving sheet 4 attached to the front end.

As shown in FIG. 1, a guide housing H ₃ is provided at a position opposite to the intersection of the rack housing H _{1 and} the pinion housing H _{2 in} a direction substantially orthogonal to each of them. The guide housing H ₃ is provided with a holding hole 23 having a circular cross section that penetrates the shaft center portion and faces the inside of the rack housing H ₁ from the back side of the rack shaft 1.
The rack guide 3 is fitted and held in the rack so as to be slidable in the axial direction.

The base end of the rack guide 3 is screwed into the outer opening of the holding hole 23 and faces a support cap 24 positioned and fixed by a lock nut 25, and is interposed between the support cap 24 and the support cap 24. The push spring 26 presses and urges inward, that is, toward the rack shaft 1.

Thus, the tip of the rack guide 3 has a rear surface (tapered surface 1) of the rack shaft 1 due to the spring force of the pushing spring 26.
2, 12) is pressed via the rack receiving sheet 4,
The rack shaft 1 is pressed toward the meshing portion with the pinion 20,
The rack shaft 1 is moved and guided while applying an appropriate preload to the meshing portion. The preload is properly adjusted by increasing or decreasing the screwing amount of the support cap 24.

With the above configuration, the steering wheel S for steering
Is operated, the pinion shaft 2 connected to the steering wheel S is rotated, and this rotation is caused by the pinion 20 and the rack tooth 10 which mesh under preload by the rack guide 3 and the shaft of the rack shaft 1. It is converted into a movement in the long direction, and this movement is transmitted to the left and right steering wheels for steering. At this time, the rack receiving sheet 4 interposed between the rack guide 3 and the back surface of the rack shaft 1 is brought into sliding contact with the tapered surfaces 12, 12 of the rack shaft 1 under the action of the spring force of the pressing spring 26. , And has a function of smoothly sliding the rack shaft 1 for steering.

A feature of the apparatus of the present invention is the mounting mode of the rack receiving sheet 4 at the tip of the rack guide 3 as described above. FIG. 2 is an enlarged cross-sectional view of the vicinity of the engagement portion between the rack shaft 1 and the pinion 20, and FIG. 3 is an exploded perspective view of the rack guide 3 and the rack receiving sheet 4.

The rack guide 3 has a guide housing H ₃
Has a cylindrical shape corresponding to the cross section of the holding hole 23 provided at the front end of the rack guide 3, and a concave groove 31 for receiving the protrusion 11 on the rear surface of the rack shaft 1 is formed at the tip end of the rack guide 3. As shown in FIG. 3, the concave groove 31 is formed so as to cross the central portion thereof, and both sides of the concave groove 31 are formed as receiving surfaces 32 and 32 which are tapered and widened at an angle corresponding to the tapered surfaces 12 and 12 on the back surface of the rack shaft 1. And
The receiving surfaces 32, 32 and the concave groove 31 form a concave portion 30 having a Y-shaped cross section corresponding to the back surface of the rack shaft 1.

In order to mount the rack receiving sheet 4 on the rack guide 3 as described above, the rack guide sheet 3 penetrates through the shaft center portion and is provided with the groove.
A locking hole 33 having a circular cross section, which opens in the approximate center of the bottom surface of 31, is formed, and further, between both side surfaces of the concave groove 31 and the receiving surfaces 32, 32 on each side, a boundary between the two is formed. Locking grooves 34, 34 having a rectangular cross section that crosses the line at the central position are formed so as to taperly reduce the depth toward the bottom of the concave groove 31.

The rack receiving sheet 4 is a resin having a low friction coefficient such as PTFE (fluorine resin) on one surface of the metal base material 4a (a surface in sliding contact with the rack shaft 1) and having excellent wear resistance. A sheet material having a two-layer structure formed by applying a coating film 4b formed by coating a material, and having both the high strength of a metal material and the slidability of a resin material. As shown in the figure, the rack guide 3 has an outer width that allows it to be fitted into the recessed groove 31 and an inner width that allows the projection 11 of the rack shaft 1 to be received, so that it projects to the side of the base material 4a. A receiving section 40 having a rectangular cross section, and sliding sections 41, 41 that are continuously provided on both sides of the receiving section 40 and that expand in a taper shape so as to correspond to the receiving surfaces 32, 32 of the rack guide 3. It is configured.

The rack receiving sheet 4 as described above has a bottomed cylindrical locking projection 42 which is provided substantially perpendicular to the central portion of the outer surface of the receiving portion 40 for attachment to the rack guide 3. Also, the substantially central portion of the boundary line between the both side surfaces of the receiving portion 40 and the sliding portions 41, 41 on each side is pushed outward over a suitable width (on the side of the base material 4a). Locking protrusion 4 formed
It has 3,43.

The outer diameter of the locking projection 42 is determined by the rack guide 3
It is made to correspond to the inner diameter of the locking hole 33 opened at the center of the bottom surface of the concave groove 31. Further, the outer width of the locking projections 43, 43 is a groove.
It is made to correspond to the inner width of the locking grooves 34, 34 formed on both side surfaces of 31, and the locking protrusions 43, 43 correspond to the locking grooves 34, 34 of the receiving portion 40. Both sides and sliding parts 41, 41
It has a continuous tapered bottom surface with an inclination with respect to. The locking protrusions 42, 43 and 43 can be collectively formed in a bending process for forming the receiving portion 40 and the sliding portions 41 and 41.

The rack receiving sheet 4 constructed as described above
Directs the base material 4a side toward the concave portion 30 at the tip of the rack guide 3,
The recessed groove 31 at the center of the recessed portion 30 and the receiving portion 40 are positioned so that the extending directions thereof are aligned with each other, and the receiving portion 40 is fitted into the recessed groove 31 as shown by an arrow in FIG. The locking projections 42 provided are press-fitted into the locking holes 33 formed in the bottom surface of the latter.

FIG. 4 is a perspective view of the rack guide 3 to which the rack receiving sheet 4 is mounted as described above. As shown in this figure, the rack receiving sheet 4 is arranged with the resin coating 4b side facing outward. The rack guide 3 including the groove 31 and the receiving surfaces 32, 32 is mounted so as to cover the entire surface of the recess 30. At this time, the locking projections 43, 43 formed between the receiving portion 40 and the sliding portions 41, 41 on both sides are provided with the concave groove 31 and the receiving surfaces 3 on both sides.
It is engaged with locking grooves 34, 34 provided between the two and 32. The locking grooves 34, 34 are tapered grooves as described above, so that the locking protrusions 43, 43 formed with a corresponding slope can be received without difficulty.

The rack receiving sheet 4 thus mounted
As shown in FIG. 2, when the rack guide 3 is assembled as described above, the ridge 11 on the back surface of the rack shaft 1 is received inside the receiving portion 40 that covers the inner surface of the concave groove 31, and the back surface is provided by the receiving surfaces 32 and 32. The surface of the sliding portions 41 supported by the rack shaft 1
The back surface is brought into contact with the tapered surfaces 12 and 12, and in this state, the rack shaft 1 slides the tapered surfaces 12 and 12.
It can move in the axial direction while sliding on 41, 41.
Rotation and flexural displacement of the rack shaft 1 about the axis during this movement are limited by the side surface of the protrusion 11 contacting the side wall of the receiving portion 40.

At this time, the surfaces of the sliding portions 41, 41 of the rack receiving sheet 4 slidingly contacting the tapered surfaces 12, 12 of the rack shaft 1 are
As described above, the rack shaft 1 is composed of the coating 4b made of a resin material having a low friction coefficient and excellent wear resistance.
The movement guide of is smoothly performed under a small sliding resistance,
It is possible to obtain a good steering feeling that continues for a long period of time.

During this time, the sliding portion 41 of the rack receiving sheet 4,
The sliding resistance of the taper surfaces 12, 12 acts on 41 as shown by the outline arrow in FIG. 4, but in the device of the present invention, the rack receiving sheet 4 is provided outside the bottom surface of the receiving portion 40. Locking projection 42 and locking projection 4 provided on both side surfaces of the receiving portion 40.
3 and 43 are engaged with the concave portion 30 of the rack guide 3, and the sliding resistance is shared by these engaging portions.
For example, even when the sliding resistance increases over time due to peeling of the coating 4b, etc., the shearing force applied to each engaging portion can be kept at a low level, and damage to these can be prevented. It is possible to mitigate the fear and prevent a sudden increase in sliding resistance.

Further, the locking projections 43, 43 project outwardly on both side surfaces of the receiving portion 40 of the rack receiving sheet 4 including the boundary portion of the sliding portions 41, 41, and the taper surfaces 12, 12 of the rack shaft 1 are formed. Since the reduction of the area of the sliding portions 41, 41 which are actually in sliding contact with each other is suppressed to a minimum, the rise of the surface pressure applied to the rack receiving sheet 4 due to the sliding of the rack shaft 1 is suppressed, and the normal steering operation is performed. Smooth slidability can be ensured, and good steering feeling can be continuously achieved for a long period of time.

FIG. 5 is an exploded perspective view of a rack guide 3 and a rack receiving sheet 4 showing another embodiment of the device of the present invention. The feature of this embodiment is that on both side surfaces of the concave groove 31 of the rack guide 3, locking grooves 34, 34 having a substantially constant depth are formed over the entire height thereof, and the rack receiving sheet 4 has There are locking projections 43, 43 corresponding to the locking grooves 34, 34 on both side surfaces of the receiving portion 40, and the rack receiving sheet 4 and the other portions of the rack guide 3 are configured as follows.
The same as those shown in FIG. 3, the same reference numerals as those in FIG.

In this configuration, the shearing force applied to the locking projections 43, 43 due to the sliding of the rack shaft 1 is shared in the lengthwise direction, so that the locking projections 43, 43 and the aforesaid It is possible to more reliably mitigate the risk of breakage of the locking projection 42. On the other hand, in this configuration, it is difficult to ensure the precision for tightly engaging the locking projections 43, 43 and the locking grooves 34, 34 over the entire length, which causes a problem of increasing the number of processing and assembling steps. To do.

In the above embodiment, the structure in which one locking groove 34 is formed on each side surface of the concave groove 31 of the rack guide 3 has been described, but a plurality of engaging grooves are formed on each side surface of the concave groove 31. A configuration may be adopted in which stop grooves are formed and a plurality of locking protrusions provided on the opposing surface of the rack receiving sheet 4 are engaged with these. However, the formation of many locking projections leads to a decrease in the actual area of the sliding portions 41, 41 slidingly contacting the rack shaft 1 and an increase in the contact surface pressure due to this decrease in the area, so an excessively large number of locking projections are formed. Providing a section is not desirable.

The cross-sectional shapes of the locking groove 34 and the locking projection 43 are not limited to the rectangular shapes shown in the above-mentioned embodiments, and it goes without saying that they can have any suitable shape such as a trapezoid, a triangle or a semicircle.

[0047]

As described above in detail, in the rack and pinion type steering device according to the first aspect of the present invention, the bottom surface of the concave groove formed in the rack guide for receiving the protrusion provided on the back surface of the rack shaft. The locking holes are formed on both side surfaces of the recessed groove, and the locking projections provided at the corresponding portions of the rack receiving sheet are engaged with the locking holes and the locking grooves, respectively. Since the rack receiving sheet is mounted on the rack guide, the sliding resistance applied to the rack receiving sheet due to the sliding of the rack shaft is shared by each of the plurality of locking protrusions, and the rack receiving sheet is damaged due to the damage of each locking protrusion. It is possible to significantly reduce the risk that the mounting state of the rack shaft on the rack guide will be impaired, and the rack shaft movement guide can be stably performed for a long period of time, and a good steering feeling can be obtained.

Further, in the rack and pinion steering apparatus according to the second aspect of the present invention, there is provided a rack receiving sheet having a two-layer structure in which a resin coating is formed on the surface of the metal base material which is in contact with the rack shaft. Since it is used, the sliding resistance due to the movement of the rack shaft is reduced, the risk that the mounting state of the rack receiving sheet is impaired is reduced, and it is possible to stably guide the movement of the rack shaft for a long period of time. Become.

Further, in the rack and pinion type steering device according to the third aspect of the present invention, the locking grooves formed on both side surfaces of the concave groove of the rack guide are tapered grooves that reduce the depth toward the bottom of the concave groove. Therefore, it is possible to forcefully receive the locking projections protruding from the portion corresponding to the mounting character of the rack receiving sheet, and it is possible to easily and securely mount the rack receiving sheet. The invention has excellent effects.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the configuration of a main part of a rack and pinion steering apparatus according to the present invention.

FIG. 2 is an enlarged cross-sectional view in the vicinity of a meshing portion between a rack shaft and a pinion.

FIG. 3 is an exploded perspective view of a rack guide and a rack receiving sheet.

FIG. 4 is an external perspective view of a rack guide to which a rack receiving sheet is attached.

FIG. 5 is an exploded perspective view of a rack guide and a rack receiving sheet showing another embodiment of the rack and pinion steering apparatus according to the present invention.

FIG. 6 is a vertical cross-sectional view showing a configuration of a main part of a conventional rack and pinion steering apparatus.

FIG. 7 is an explanatory view of a state in which a rack receiving sheet is attached to a rack guide in a conventional rack and pinion steering apparatus.

[Explanation of symbols]

1 rack shaft 2 pinion shaft 3 rack guide 4 rack receiving sheet 10 rack teeth 20 pinion 31 concave groove 32 receiving surface 33 locking hole 34 locking groove 40 receiving portion 42 locking projection 43 locking projection H ₁ rack housing H ₂ pinion Housing H ₃ Guide housing

Continued front page    (72) Inventor Yasunori Takeda             3-5-8 Minamisenba, Chuo-ku, Osaka-shi, Osaka               Koyo Seiko Co., Ltd.

Claims (3)

[Claims] 1. A rack shaft having a protrusion extending in the axial direction on the back surface of a meshing portion with a pinion, and a recess groove for receiving the protrusion, and a recess corresponding to the back surface of the rack shaft. A rack guide having a rack guide and a rack receiving sheet that is attached to the recess and abuts on the back surface of the rack shaft, and the rack guide that presses the rack shaft from the back surface side through the rack receiving sheet causes In a rack and pinion type steering device configured to move and guide the rack shaft while applying a preload to a meshing portion, the rack guide includes locking holes formed on a bottom surface of the groove and both side surfaces of the groove. The rack receiving sheet is provided with a formed engaging groove, and the rack receiving sheet is provided on a surface facing the concave portion so as to have engaging protrusions respectively corresponding to the engaging hole and the engaging groove. The locking hole Rack-pinion type steering apparatus characterized by by engaging the beauty locking grooves are fitted in the rack guide. 2. The rack and pinion steering apparatus according to claim 1, wherein the rack receiving sheet has a resin coating film formed on a surface of a metal base material which is in contact with the rack shaft. 3. The locking groove is a taper groove having a depth that decreases toward the bottom of the groove.
The described rack and pinion steering device.