JPH09226604A - Rack guide for rack pinion type steering device and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve assemblability of a rack guide slidably supporting a rack. SOLUTION: A rack guide 40 is slidably fitted into a hole formed in a gear housing of a rack pinion type steering device, so as to support a back surface of a rack. A rack guide main unit 42 is formed of metal or sintered material, a resin material 44 is integrally molded in a rack slide surface of the main unit, contact surface with a yoke stopper and a peripheral surface slid in the hole. The peripheral surface is divided in a circumferential direction, four part broad width grooves 42e are formed, the resin material 44 (44b) is integrally molded in these grooves 42e. Accordingly, in a peripheral surface of this rack guide 40, the metal part 42 and the resin part 44 are alternately arranged in each four part. Accordingly, generation of a rattle sound can be prevented by sliding with the resin part 44, sufficient rigidity can be obtained by the metal part 42. The metal part 42 and the resin part 44 are integrally formed, so that assemblability is extremely excellent.

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, and more particularly to a rack guide for slidably supporting a rack and a method for manufacturing the rack guide.

[0002]

2. Description of the Related Art A rack and pinion type steering device is
The pinion that is rotated by operating the steering wheel, the rack that meshes with the pinion, and that reciprocates in the axial direction with the rotation of the pinion, is slidably fitted in the hole formed in the gear housing, and reciprocates. A rack guide that supports the back surface of the moving rack, a yoke stopper screwed to the opening side of the hole of the gear housing, and a rack guide interposed between the rack guide and the yoke stopper. And a spring that biases the pinion side toward the pinion side. The outer peripheral surface of the rack guide slides on the inner surface of the hole of the gear housing, and the back surface of the rack is slidably received by the recess formed in the end surface on the rack side. In such a steering device, in order to smoothly rotate the pinion and at the same time slide the rack smoothly, it is necessary to provide a suitable backlash between the rack teeth and the pinion teeth.
In addition, it is necessary to provide a space between the rack guide and the gear housing that houses the rack guide so that the rack guide can be inserted when the rack guide is assembled. The surface of the rack guide on the side opposite to the recess for receiving the rack contacts the yoke stopper so that the backward limit thereof is restricted.

As the rack guides as described above, those integrally formed of a metal or a sintered metal material or integrally formed of a resin material have been conventionally known. However, the one integrally molded with a metal or a sintered metal material has sufficient rigidity and strength, but the sliding part with the inner surface of the hole of the gear housing, the sliding part with the back surface of the rack, or the yoke stopper. Since all the contact parts are metal contacts, when the reverse input from the tire acts on the rack when the steering wheel is operated or the vehicle is running, the rack teeth are perpendicular to the moving direction due to the meshing of both gears. Since vertical force is applied to the rack guide, a force is applied to the rack guide in the vertical direction, causing the rack guide to slide with the inner surface of the hole in the gear housing, slide with the back of the rack, or contact with the yoke stopper. However, there is a problem in that the so-called rattle noises are generated by interfering with each other. On the other hand, in the case of a rack guide integrally molded with a resin material, sliding performance and sound performance are good, but there are problems such as insufficient rigidity and insufficient strength.

Therefore, in order to eliminate the above-mentioned drawbacks, the main body of the rack guide is made of metal or a sintered metal material, and a separate resin sheet is attached to the sliding surface of the rack guide main body with the rack, or a yoke stopper is provided. The one in which an independent annular plate made of resin is interposed on the contact surface with and the combination of these are conventionally used.

A rack guide constructed by combining the above-described rack guide main body made of metal or a sintered metal material and a resin member provided at the sliding portion of the rack and the contact portion with the yoke stopper. An example of the specific configuration of the above will be described with reference to the drawings. FIG. 12 is a vertical cross-sectional view taken along the input / output shaft of a rack and pinion type power steering device equipped with the rack guide having the above configuration. In the figure, 2
Is an input shaft (stub shaft) connected to a steering wheel (not shown) for rotation, and 4 is an output shaft (pinion shaft) having a pinion 4a formed at one end thereof. Is coupled by a torsion bar 6 disposed in a space 2a formed in the shaft core portion of the shaft, is rotatably supported in the gear housing 14 and the valve housing 16 by the bearings 8, 10, 12, and is relatively angled by a predetermined angle. It can be rotated.

The pinion 4a meshes with the rack 18 to form a rack and pinion type steering gear. A tubular portion 14a is formed in a portion of the gear housing 14 located on the rear side of the rack 18, and the tubular portion 14a is formed.
The rack guide 20 is slidably fitted in the hole 14b of a. A yoke stopper 28 is screwed and fixed to the opening of the tubular portion 14a.
8 is urged toward the pinion 4a side by the spring 30 arranged between the rack guide 20 and the rack guide 20 to elastically contact the pinion 4a.

The main body 22 of the rack guide 20 has a substantially cylindrical shape made of a metal or a sintered metal material. The rack guide body 22 has an arc-shaped or substantially Y-shaped concave portion 22a for receiving the back surface of the rack 18, which is formed at the end of the gear housing 14 on the inner side of the tubular portion 14a, that is, on the rack 18 side. A separate resin sheet 24 that is in direct sliding contact with the rack 18 is mounted in the recess 22a. Further, between the rack guide main body 22 and the yoke stopper 28 fixed to the opening side of the hole 14b of the gear housing 14, the resin annular plate 2 is provided.
6 is interposed so that the rack guide body 22 made of the metal or the sintered metal material and the yoke stopper 28 do not come into direct contact with each other.

[0008]

The conventional rack guide 20 having the above-described structure includes a main body 22 made of a metal or a sintered metal material, a resin sheet 24 that directly contacts the back surface of the rack 18, and a yoke stopper 28. Since it is composed of three members including the resin plate 26 arranged in
There was a problem that the assemblability was poor and the number of steps was large. Further, since the portion (outer peripheral surface) of the gear housing 14 that slides on the inner peripheral surface of the hole 14b is the rack guide body 22 made of a metal or a sintered metal material, a rattle noise is generated during operation as described above. There was also.

The present invention has been made in order to eliminate the above-mentioned drawbacks, has sufficient strength and rigidity, and exhibits good sliding performance to prevent the generation of abnormal noise and to prevent the occurrence of abnormal noise. An object of the present invention is to provide a guide, particularly a rack guide which is greatly improved in assembling ability with respect to the rack guide formed of the above three members.

It is another object of the present invention to provide a method for manufacturing the rack guide having the above structure.

[0011]

A rack guide of a rack and pinion type steering device according to the present invention is slidably fitted in a hole formed in a housing, and is engaged with a pinion to reciprocally move the back surface of the rack. In particular, the main body of the rack guide is formed of a metal or a sintered metal material, and a resin material is integrally molded in a groove provided in a part of the outer peripheral surface of the rack guide main body. By doing so, the outer peripheral surface of the rack guide main body that slides on the inner surface of the hole of the housing is composed of a metal or sintered metal material portion and a resin material portion slightly protruding outward from the metal or the like portion. In addition, the resin material is integrally molded on the sliding surface of the rack guide body with the rack.

Further, in the method for manufacturing the rack guide of the rack and pinion type steering device according to the present invention, the back surface of the rack which is slidably fitted in the hole formed in the housing and reciprocates by meshing with the pinion. A method of manufacturing a rack guide that slidably supports, comprising molding a main body of a rack guide in which a groove is formed in a part of an outer peripheral surface that slides on an inner surface of the hole of the housing with a metal or a sintered metal material. Then, after housing this rack guide body in the mold, inject resin material into the groove, and slide the rack guide body on the sliding surface with the rack and, if necessary, on the opposite side of the sliding surface with the rack. By injecting a resin material integrally into the surface of the rack guide body, the outer peripheral surface of the rack guide main body may be made of a metal or a sintered metal material and a resin material slightly protruding outward from the metal or the like. Those formed from a part made.

In the rack guide of the rack and pinion type steering device according to the present invention, the sliding surface with respect to the hole of the gear housing is divided into a resin material portion and a metal portion. While providing sliding performance and preventing rattle noise, when an excessive load is applied, it can be received by the part made of metal or sintered metal material, so it exhibits sufficient rigidity and strength. The durability can be improved. Further, by assembling the rack guide by integral molding by the above manufacturing method, the assembling property can be greatly improved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. The present invention relates to an improvement of a rack guide slidably fitted in a hole formed in a gear housing. The basic configuration of a rack and pinion type steering device to which this rack guide is applied is as described above. The structure may be the same as that shown in FIG. 10 or may be any other known structure. Therefore, in the present embodiment, in FIG.
The parts corresponding to the configuration of 0 will be described with the reference numerals. A tubular portion 14a is formed on the rear surface side of the rack 18 in a portion where the rack 18 and the pinion 4a in the gear housing 14 mesh with each other. The rack guide 40 shown in FIG. 4 is slidably fitted.

The rack guide 40 has a substantially cylindrical main body 42 made of a metal or a sintered metal material.
An hourglass-shaped through hole 42a is formed in the center of the main body 42 made of metal or the like. In addition, the rack guide body 4
The rack 18 has an end surface (lower surface in FIG. 1) on the rack 18 side.
Arc-shaped recess 42b that substantially matches the outer surface shape of the rear surface of the
Are formed. On the other hand, a flat shallow recess 42c is formed on the end surface (upper surface in FIG. 1) of the rack guide body 42 on the side opposite to the rack 18, and the rack 18 is pinion 4a.
A spring seat is formed to receive the spring 30 biased to the side. The shape of the recess 42b that receives the rack 18 is not limited to that shown in the drawing, and the rack 18
The shape is appropriately changed according to the outer surface shape. Further, the through hole 42a in the central portion is used for positioning the main body of the rack guide and the resin material at the time of manufacturing, and is not limited to the hourglass shape and may be any non-circular shape that can prevent rotation. Further, if the rack receiving portion side (lower side in FIG. 1) is used for positioning, this hole can be omitted.

The main body 42 of the rack guide made of the above-mentioned metal or sintered metal material is made of resin at the sliding portion with the rack 18, the sliding portion with the hole 14b of the gear housing 14 and the abutting portion with the yoke stopper 28, respectively. The material 44 is integrally molded. A resin material 44 integrally formed on the entire surface of the sliding portion with the rack 18 except for the periphery of the through hole 42a.
a is fixed (see FIG. 4).

Further, the outer peripheral surface of the rack guide main body 42 that slides on the inner peripheral surface of the hole 14a of the gear housing 14 is divided in the circumferential direction, and the resin portion 44b at four locations and a metal (or a sintered metal material). The portions 42d are arranged alternately (see FIG. 2). The resin portion 44b protrudes to the outer surface side by a slight amount from the surface of the metal portion 42d. However, this protrusion amount is such that when a load larger than a predetermined value is applied, the resin portion 44b
The deformation is such that the metal portion 42d is so small that it can receive this load. In this way, the resin portion 44
Since b protrudes outward from the metal portion 42d, when the rack guide 40 slides on the inner peripheral surface of the hole 14b formed in the gear housing 14, good sliding by the resin portion 44b is achieved. The characteristics can be obtained. Moreover, when a load larger than a predetermined value is applied to the rack guide 40, the resin portion 44b is compressed and deformed so that the metal portion 42d receives the load. Therefore, the metal portion 42d has excellent rigidity and strength. Can be demonstrated. Note that arrow A in FIG. 2 indicates the axial direction of the rack 18 supported by the rack guide 40, and arrow B indicates the direction perpendicular to the axis of the rack 18.

Here, the direction of the force acting on the outer periphery of the rack guide 40 in the steering apparatus according to the present invention will be considered. First, it is generally known that the force generated by the engagement between the rack 18 and the pinion 4a acts in the direction in which the rack 18 rolls, that is, in the direction perpendicular to the axis of the rack 18 (F ₁ direction in FIG. 8). (See JP-B-60-13867, page 149, column 6, lines 40 to 4 and FIG. 2). Along with the sliding of the rack 18, a force in the axial direction of the rack 18 also acts on the rack guide 40 (see F _{0 in} FIG. 8). Therefore, a force in the substantially F ₃ direction of FIG. 8 acts on the sliding portion between the rack guide 40 and the inner surface of the hole 14a of the gear housing 14 (when the sliding direction of the rack 18 is the opposite direction, F The direction of ₃ is also reversed). Therefore, in the conventional rack and pinion steering device, there is a problem in that the rattle noise is generated by interfering with each other in the F ₃ direction, or that a wear is generated at this portion when a load larger than a predetermined value is applied. It was

In the embodiment shown in FIG. 2, four resin portions 44b on the outer peripheral surface are arranged in the axial direction of the rack 18 (direction of arrow A) and in the direction perpendicular to this direction (direction of arrow B). There is. Even with this arrangement, as described above, the resin portion 4
Good sliding performance due to 4b and strength due to the metal portion 42d can be obtained. For example, as shown in FIG. 9, the resin portion 44 is perpendicular to the axial direction A of the rack 18 and the axial line of the rack 18. If you place it in the part between the different directions B,
Further excellent effects can be achieved.

Further, the metal portion 42d exposed on the outer peripheral surface
The ratio of the resin portion 44b to the resin portion 44b is not limited to that shown in the figure, and can be appropriately set within a range in which both the sliding performance of the resin and the rigidity of the metal can be exhibited. 10 and 11 show another example of the arrangement of the resin portion 44 and the metal (or sintered metal material) portion 42 on the outer peripheral surface of the rack guide 40. FIG. 10 shows the outer peripheral surface in the circumferential direction. 1 divided into 12 and 6 resin portions 44 and 6 metal portions 42 are alternately arranged.
In No. 1, the outer peripheral surface is divided into 16 parts in the circumferential direction, and the resin parts 44 and the metal parts 42 are arranged alternately at eight positions.

Further, a spring seat 42c recessed toward the center is formed on the end surface of the rack guide 40 on the side of the yoke stopper 28, and a resin material 44c is integrally formed on the outer peripheral surface around the spring seat 42c. Are fixed by (see FIGS. 1 and 3). As described above, the rack 18 side of the rack guide main body 42 made of a metal or a sintered metal material,
The resin material 4 is provided on the outer peripheral surface and the yoke stopper 28 side, respectively.
Since 4 (44a, 44b, 44c) are integrally molded, it is possible to prevent rattle noise from being generated at each sliding portion and abutting portion. Further, since the metal (or sintered metal material) portion 42d is partially exposed on the outer peripheral surface so that the inner surface of the hole 14b of the gear housing 14 can slide, it is possible to obtain sufficient rigidity and strength. You can Moreover, since the resin portion 44 and the metal (or sintered metal material) portion 42 are integrally molded and have a one-piece structure, the assembling property is significantly improved.

Next, a method of manufacturing the rack guide 40 having the above structure will be briefly described. First, the body 42
Is made of a metal or a sintered metal material. On the outer peripheral surface of the rack guide body 42, a plurality of wide grooves 42e are formed in the arrangement as shown in FIG. afterwards,
After the rack guide main body 42 made of this metal or sintered metal material is put into a mold, the surface of the recess 42b on the side receiving the rack 18, the outer peripheral portion of the end surface on the side of the yoke stopper 28, and the groove 42e of the outer peripheral surface are formed. Then, a resin material is injected to form the rack guide 40 in which the metal (sintered metal material) portion 42 and the resin portion 44 are integrated. As described above, according to the method of the present invention, the portion 42 made of the metal or the sintered metal material and the portion 44 made of the resin material can be integrally formed by a simple process.

FIGS. 5 to 7 show other embodiments of the rack guide according to the present invention. In the rack guide 50 of FIG. 5, the rack 18 of the rack guide body 52 made of metal or sintered metal material is used. As in the first embodiment, the resin material 54 (54a, 5a) is provided on the contact surface between the recess 52b which is slidably received and the yoke stopper 28.
4b) is integrally molded. A spiral groove 52f is formed on the outer peripheral surface of the rack guide body 52 that slides in the hole 14b of the gear housing 14.
A resin material 54c is integrally molded in 2f. Also in this embodiment, the outer peripheral surface is divided (in this example, almost in the axial direction), and the metal (or sintered metal material) portions 52 and the resin portions 54 are alternately arranged, as in the above-described embodiment. Therefore, as in the case of the first embodiment described above, good sliding performance as a resin material with respect to the hole 14b of the gear housing 14 and
It can exhibit excellent rigidity and strength as a metal. Moreover, because of the one-piece structure, the assembling property is remarkably improved as compared with the conventional rack guide 20 shown in FIG.

FIG. 6 shows still another embodiment.
The rack guide 60 includes a rack guide body 62 made of a metal or a sintered metal material and a surface on the rack 18 side.
The resin material 64 (64a, 64b) is integrally molded on the contact surface with the yoke stopper 28, as in the above-described embodiments. Further, a plurality of (two in this embodiment) parallel annular grooves 62g are formed on the outer peripheral surface of the rack guide body 62 that slides in the hole 14b of the gear housing 14, and the resin is provided in the annular groove 62g. The material 64c is integrally molded, the outer peripheral surface is divided in the axial direction, and the metal (or sintered metal material) portions 62 and the resin portions 64 are alternately arranged. Therefore, the same effect as each of the above-described embodiments can be obtained. The width and the number of the resin portions 64c on the outer peripheral surface are not limited to those shown in the figure, and can be changed as appropriate.

FIG. 7 shows still another embodiment,
The rack guide 70 includes a rack guide body 72 made of a metal or a sintered metal material and a surface on the rack 18 side.
On the contact surface with the yoke stopper 28, the resin material 74 (74a, 74b) is integrally molded, and the rack guide main body 72 that slides in the hole 14b of the gear housing 14 is used as in the above embodiments. 7, two grooves 72h in the axial direction (vertical direction in FIG. 7) are formed on both sides, and two grooves 72i in the direction intersecting with the front side and the other side in FIG. 7, are formed. The resin material 74 is placed in the grooves 72h and 72i.
c and 74d are integrally molded. Also in this embodiment, the same operational effects as those of the above embodiments can be obtained.

The structure of the present invention is not limited to that shown in each of the above embodiments, but the outer peripheral surface of the rack guide body made of metal or a sintered metal material is made of a metal material and a resin material. It may be constituted by both of the parts, and in particular, it may be divided into a plurality of parts and arranged so that the metal (or sintered metal material) part and the resin part are alternately located.

[0027]

As described above, according to the present invention, the back surface of the rack that is slidably fitted in the hole formed in the housing and that reciprocates by engaging with the pinion is slidably supported. In the rack guide, the main body of the rack guide is formed of a metal or a sintered metal material, and the resin material is integrally molded in a groove provided in a part of the outer peripheral surface of the rack guide main body. The outer peripheral surface of the rack guide body that slides on the inner surface is composed of a metal or sintered metal material portion and a resin material portion that slightly protrudes outward from the metal or the like portion, and the rack guide body has By integrally molding the resin material on the sliding surface with the rack, it is possible to obtain sufficient rigidity and strength and prevent rattle noise from being generated. Moreover, since the resin and metal etc. are integrated structure, the assemblability is improved,
The number of steps can be reduced.

Further, according to the method of the present invention, the main body of the rack guide, in which a groove is formed in a part of the outer peripheral surface which slides on the inner surface of the hole of the housing, is molded from a metal or a sintered metal material, and the main body of the rack guide is formed. After accommodating in the mold, by injecting a resin material into the groove, the outer peripheral surface of the rack guide main body was made to project a little on the outer surface side from the portion made of metal or sintered metal material and the portion made of metal or the like. It should be made of resin material and the resin material should be injected into the sliding surface of the rack guide body with the rack and, if necessary, the surface opposite to the sliding surface with the rack. Thus, it is possible to obtain a rack guide in which a metal or the like and a resin which are easily assembled are integrated.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a rack guide of a rack and pinion type steering device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of the rack guide.

FIG. 3 is a view of the rack guide as viewed in the direction of arrow III.

FIG. 4 is a view of the rack guide as seen from the direction IV.

FIG. 5 is a front view of a rack guide according to another embodiment.

FIG. 6 is a front view of a rack guide according to still another embodiment.

FIG. 7 is a front view of a rack guide according to still another embodiment.

FIG. 8 is a diagram illustrating a direction of a force that acts on an outer peripheral surface of a rack guide.

FIG. 9 is a diagram illustrating a more preferable arrangement of resin portions.

FIG. 10 is a view of a rack guide according to still another embodiment.
FIG.

FIG. 11 is a view of a rack guide according to still another embodiment.
FIG.

FIG. 12 is a vertical cross-sectional view showing an example of a conventional rack and pinion steering device including a rack guide.

[Explanation of symbols]

 4a Pinion 14 Housing (gear housing) 14b Housing (gear housing) hole 18 Rack 40 Rack guide 42 Rack guide body 44 Resin material

Claims (5)

[Claims] 1. A rack guide slidably fitted in a hole formed in a housing and slidably supporting a back surface of a rack that meshes with a pinion and reciprocates, the main body of the rack guide being made of metal. Alternatively, the outer peripheral surface of the rack guide body that slides on the inner surface of the hole of the housing can be formed by integrally molding a resin material in a groove provided in a part of the outer peripheral surface of the rack guide body while being formed of a sintered metal material. , A metal or sintered metal material portion and a resin material portion slightly protruding outward from the metal or the like portion, and the resin material is integrally molded on the sliding surface of the rack guide body with the rack. A rack guide for a rack and pinion type steering device characterized in that 2. The outer peripheral surface of the rack guide body is divided in the circumferential direction, and portions made of metal or sintered metal material and portions made of resin material are alternately arranged. Rack guide for the rack and pinion type steering device described in. 3. The outer peripheral surface of the rack guide main body is divided in the axial direction, and portions made of metal or a sintered metal material and portions made of resin material are alternately arranged. The rack guide of the rack and pinion type steering device according to 1. 4. The rack and pinion type steering device according to claim 1, wherein a resin material is integrally molded on the surface of the rack guide body opposite to the sliding surface with the rack. Rack guide. 5. A method of manufacturing a rack guide, which is slidably fitted in a hole formed in a housing and slidably supports a back surface of a rack that meshes with a pinion and reciprocates. The main body of the rack guide, in which a groove is formed in a part of the outer peripheral surface that slides on the inner surface of the hole, is molded with a metal or a sintered metal material, the rack guide main body is housed in a mold, and then the resin is inserted into the groove. The outer periphery of the rack guide body is injected by injecting the resin material into the sliding surface of the rack guide body with the rack and, if necessary, the surface opposite to the sliding surface with the rack. The rack and pinion steering device is characterized in that the surface is formed of a portion made of a metal or a sintered metal material and a portion made of a resin material slightly protruding outward from the metal or the like. Method of manufacturing guide.