JP6442764B2 - Rack guide and rack and pinion type steering apparatus provided with the rack guide - Google Patents

Description

  The present invention relates to a technology of a rack guide and a rack and pinion type steering apparatus including the rack guide.

Generally, a rack and pinion type steering device includes a gear case, a pinion that is pivotally supported by the gear case, a rack bar that is formed with rack teeth that mesh with the pinion, and the rack bar that can slide within the gear case. And a coil spring that urges the rack guide to be pressed against the rack bar.
A hollow housing portion extending in a cylindrical shape is integrally formed on the gear case, and a cylindrical rack guide is coaxially inserted into the housing portion.
As a result, the rack guide has a minute gap (clearance) with the inner peripheral surface of the housing part, and is perpendicular to the moving direction of the rack bar (more specifically, the axial direction of the rack bar). It arrange | positions so that sliding is possible (for example, refer to "patent document 1").

JP2013-28285A

In the conventional rack and pinion type steering apparatus having such a configuration, for example, when the rack bar is bent unexpectedly, the rack bar slides on the sliding support surface of the rack guide (when the rack bar is supported in the rack guide). It will slide while locally abutting against the end of the surface directly contacting the surface.
As a result, the smooth sliding operation of the rack bar is hindered, causing abnormal noise and damage to the rack bar or rack guide.

  The present invention has been made in view of the present problems described above, and supports a rack bar meshed with a pinion pivotally supported by a gear case via rack teeth so as to be movable in the axial direction. A rack guide and a rack and pinion type steering apparatus including the rack guide, and a rack guide capable of ensuring a smooth sliding operation of the rack bar even when the rack bar is bent unexpectedly, and It is an object of the present invention to provide a rack and pinion steering device including the rack guide.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

In other words, the rack guide according to claim 1 of the present invention is a rack guide that supports a rack bar that meshes with a pinion that is pivotally supported by a gear case via rack teeth so as to be movable in the axial direction. A convex surface of the bar opposite to the side on which the rack teeth are formed, and a concave sliding support surface that is slidably in contact with the sliding direction of the rack bar and the rack Only the edges of both sides located on both sides in the direction orthogonal to the axial direction of the guide are formed with inclined surfaces that gradually incline in the direction away from the rack bar toward the end on the moving direction side , The inclined surface is not formed at the edge of the bottom surface located in a range excluding the both side portions, and the bottom surface follows the convex surface of the rack bar from one end to the other end in the movement direction of the rack bar. Concave Characterized in that it is formed into a shape.

As described above, in the rack guide according to the present invention, the sliding support surface is inclined in the direction of separating from the rack bar gradually toward the edge in the direction perpendicular to the direction of movement of the rack bar. Since the inclined surface is formed, even if the rack bar is bent unexpectedly, the rack bar can be locally abutted against the end of the sliding support surface via the inclined surface. It can be avoided.
In other words, the rack bar comes into surface contact with the end portion of the sliding support surface via the inclined surface, and the surface pressure at the contact portion is relieved, and the smooth sliding operation of the rack bar is ensured. Can do.

  The rack guide according to claim 2 of the present invention is characterized in that the inclined surface is formed in a crowning shape.

  As described above, in the rack guide of the present invention, the inclined surface is formed by a crowning shape having a smooth curve. The inclined surfaces can be brought into contact with each other, and the rack bar can be firmly supported.

  The rack guide according to claim 3 of the present invention is characterized in that the inclined surface is formed in an end relief shape.

  As described above, in the rack guide according to the present invention, the inclined surface is formed by an end relief shape that is relatively easy to process, and therefore the cost can be reduced.

  On the other hand, a rack and pinion steering device according to a fourth aspect of the present invention includes the rack guide according to any one of the first to third aspects.

  As described above, the rack and pinion type steering apparatus of the present invention includes the rack guide of the present invention described above, so that even if the rack bar is bent unexpectedly, Smooth sliding operation can be ensured.

  As effects of the present invention, the following effects can be obtained.

  That is, according to the rack guide and the rack and pinion type steering apparatus including the rack guide according to the present invention, it is possible to ensure a smooth sliding operation of the rack bar even when the rack bar is bent unexpectedly. it can.

The cross-sectional side view which showed the whole structure of the rack and pinion type steering apparatus provided with the rack guide which concerns on one Embodiment of this invention. The perspective view which showed the structure of the rack guide. It is the figure which showed the shape of the front-end part of the rack guide shown by the arrow Y in FIG. 2, (a) is a rack guide in case the crowning shape is formed in the front and back both ends of a sliding support surface. The partial cross-sectional top view which showed the front-end part, (b) is the partial cross-sectional top view which showed the front-end part of the rack guide in case the end relief shape is formed in the front and back both ends of a sliding support surface.

  Next, embodiments of the invention will be described.

[Rack and pinion steering device 1]
First, an overall configuration of a rack and pinion steering device 1 (hereinafter simply referred to as “steering device 1”) including a rack guide 6 embodying the present invention will be described with reference to FIG.
In the following description, for convenience, the vertical direction in FIG. 1 is described as the vertical direction of the steering device 1.
In FIG. 1, the direction of the arrow A is defined as the front of the steering device 1.

The steering device 1 in the present embodiment is a device for converting, for example, a rotation operation of a pinion 2 rotated by a steering wheel (not shown) into a straight movement operation of the rack bar 3.
The steering device 1 is provided with a gear case 4, and one end of the pinion 2 is inserted into the gear case 4, for example, toward the front (in the direction of arrow A in FIG. 1).

Here, a pinion tooth 2 a is formed at one end of the pinion 2.
In the gear case 4, one end of the pinion 2 is pivotally supported via a pair of bearings 5 and 5 arranged with the pinion teeth 2 a interposed therebetween.

  The other end of the pinion 2 extends in the axial direction outside the gear case 4 and is connected to a steering wheel (not shown).

A rack bar 3 that meshes with the pinion 2 is disposed inside the gear case 4.
Rack teeth 3a are formed on the outer peripheral surface of the central portion in the axial direction of the rack bar 3, and the back surface (the surface opposite to the side on which the rack teeth 3a are formed) with respect to the rack teeth 3a has a predetermined curvature. It is a convex surface 3b having a circular arc shape in a sectional view having a radius.

  The rack bar 3 is disposed below the pinion teeth 2a so as to extend in a direction orthogonal to the pinion 2 (for example, the left-right direction in the present embodiment), and the pinion teeth 2a and the pinion teeth 2a Meshed.

  Both end portions of the rack bar 3 protrude from the inside of the gear case 4 to the outside, and the rack bar 3 slides in the axial direction (left and right direction) via a bearing member (not shown). Supported as possible.

A hollow housing portion 4 a extending in a cylindrical shape is integrally formed on the lower surface of the gear case 4.
The housing portion 4a is formed at a position such that the rack bar 3 is sandwiched between the housing 4a and the pinion 2, and the rack bar 3 slides on the inner peripheral portion (space portion surrounded by the inner peripheral surface). A rack guide 6 that is supported is slidably disposed in the extending direction of the housing portion 4a (in the present embodiment, the vertical direction).

  And the rack guide 6 is urged | biased by the rack bar 3 side by the compression coil spring 8 as an elastic member arrange | positioned between the cover members 7 which obstruct | occlude the lower end of the housing part 4a.

  In the steering apparatus 1 having the above-described configuration, when the pinion 2 is rotated around the axis via a steering wheel (not shown), the rotational driving force applied to the pinion 2 is the pinion teeth. 2a and rack teeth 3a are transmitted in this order, and converted into a propulsive force in the axial direction of the rack bar 3.

[Rack guide 6]
Next, the configuration of the rack guide 6 will be described in detail with reference to FIGS.
In the following description, for convenience, the vertical direction in FIG. 2 is described as the vertical direction of the rack guide 6.
2 and 3, the direction of the arrow A is defined as the front of the rack guide 6.

As shown in FIG. 1, the rack guide 6 supports the rack bar 3 engaged with the pinion 2 so as to be slidable in the axial direction of the rack bar 3 while pressing the rack bar 3 toward the pinion 2 side. Is.
The rack guide 6 includes a sliding plate piece 61 that comes into contact with the convex surface 3b of the rack bar 3, a rack guide main body 62 on which the sliding plate piece 61 is mounted, and the like.

The sliding plate piece 61 is configured to have a concave surface 61 a having an arc shape that is substantially the same as the convex surface 3 b of the rack bar 3.
In addition, a protruding portion 61b that protrudes on the side facing the concave surface 61a is formed at the center of the sliding plate piece 61 by, for example, press drawing.

On the other hand, the rack guide main body 62 is constituted by a cylindrical metal member made of, for example, Fe-based sintered metal or aluminum alloy, and is formed at one end thereof in a circular arc shape in cross section along the sliding plate piece 61. The formed plate piece support surface 62a is formed, and a cylindrical hollow portion 62b capable of holding the compression coil spring 8 is formed at the other end.
In addition, a groove portion 62c having substantially the same shape as the protruding portion 61b of the sliding plate piece 61 described above is formed in the center portion of the plate piece support surface 62a.

Then, at one end portion of the rack guide main body 62, the sliding plate piece 61 is disposed via the plate piece support surface 62a. At this time, the protruding portion 61b of the sliding plate piece 61 is inserted into the groove portion 62c of the plate piece support surface 62a.
As a result, the sliding plate piece 61 is firmly held at one end of the rack guide body 62.

  The rack guide 6 having such a configuration is disposed coaxially with the housing portion 4a inside the gear case 4 with the concave surface 61a of the sliding plate piece 61 facing the rack bar 3 side. Further, the other end portion of the compression coil spring 8 whose one end portion is fixed by the lid member 7 is held via a cylindrical hollow portion 62 b of the rack guide main body 62.

Thus, the rack guide 6 is in contact with the convex surface 3b of the rack bar 3 via the concave surface 61a of the sliding plate piece 61, and the inner peripheral portion of the housing portion 4a is pivoted via the outer peripheral surface 62d of the rack guide body 62. It is arranged so as to be slidable in the central direction (in this embodiment, the vertical direction). That is, in the rack guide 6, the concave surface 61 a of the sliding plate piece 61 is provided as a “sliding support surface” that is directly contacted when the rack bar 3 is slidably supported.
At this time, the rack guide 6 is always urged toward the rack bar 3 by the compression coil spring 8.

By the way, in this embodiment, the inclined surface 63 (refer FIG. 3) is formed in the edge of the sliding support surface of the rack guide 6 (more specifically, the concave surface 61a of the sliding plate piece 61). It is said.
Specifically, as shown in FIG. 2, the sliding support surface composed of the concave surface 61 a of the sliding plate piece 61 is orthogonal to the moving direction of the rack bar 3 (the left-right direction indicated by arrow B in FIG. 2). The inclined surfaces 63 are formed on both sides in the direction, that is, on the front and rear edges indicated by the region X in FIG.

Here, the inclined surface 63 gradually inclines away from the rack bar 3 from the central part in the moving direction (left-right direction) of the rack bar 3 toward the moving direction side ends (right end part and left end part). In this way, it is formed.
For example, as an example, as shown in FIG. 3A, the inclined surface 63 (hereinafter referred to as “first inclined surface 63A” as appropriate) is formed in a crowning shape.
Specifically, the first inclined surface 63A has a left and right side in a cross-sectional shape on a plane orthogonal to the sliding direction (vertical direction) of the rack guide 6 at the front (or rear) edge of the concave surface 61a. It is formed with a substantially arc-shaped smooth curved shape that gradually inclines in a direction away from the rack bar 3 from the center of the direction toward the right end and the left end.
Thereby, for example, even if the rack bar 3 is rolled in the front-rear direction, the outer peripheral surface of the rack bar 3 can always be brought into contact with the first inclined surface 63A. 3 can be firmly supported.

As another example, as shown in FIG. 3B, the inclined surface 63 (hereinafter referred to as “second inclined surface 63B” as appropriate) is formed in an end relief shape.
Specifically, the second inclined surface 63B has a left and right side in a cross-sectional shape on a plane perpendicular to the sliding direction (vertical direction) of the rack guide 6 at the front (or rear) edge of the concave surface 61a. It forms with the linear shape which inclines in the direction which leaves | separates from the rack bar 3 gradually as it goes to a right end part and a left end part from the center part of a direction.
As described above, the end relief shape has a relatively easy configuration including a planar shape, so that the manufacturing cost can be reduced and it is economical.

As described above, in the rack guide 6 of the present embodiment, the direction orthogonal to the moving direction of the rack bar 3 (the left-right direction in the present embodiment) on the sliding support surface (the concave surface 61a of the sliding plate piece 61). Since the inclined surface 63 which inclines in the direction which leaves | separates from the rack bar 3 gradually as it goes to the said moving direction is formed in the edge part of both sides (in this embodiment both sides in the front-back direction), even if it is a rack bar unexpectedly. 3, the rack bar 3 locally abuts against the end portions (the right end portion and the left end portion in this embodiment) of the sliding support surface via the inclined surface 63. Can be avoided.
That is, the rack bar 3 comes into surface contact with the end portions (right end portion and left end portion) of the sliding support surface via the inclined surface 63, and the surface pressure at the contact portion is relieved, and the rack bar 3 Smooth sliding operation can be ensured.

In the present embodiment, the rack guide 6 is configured by the sliding plate piece 61, the rack guide body 62, and the like, but is not limited thereto.
That is, in the rack guide body 62, the sliding plate piece 61 can be omitted by directly coating the end surface on the rack bar 3 side with a resin coating film, for example.
In this case, the rack guide 6 is constituted only by the rack guide main body 62, and a “sliding support surface” is formed on the end surface on the rack bar 3 side, and the rack bar 3 on the sliding support surface is formed. At the edges on both sides in the direction orthogonal to the moving direction, inclined surfaces are formed that gradually incline in the direction away from the rack bar 3 toward the moving direction.

  Further, the arrangement position of the rack guide 6 is not limited to the present embodiment, and the rack bar 3 is pressed to the pinion 2 side through the concave surface 61a (sliding support surface) of the sliding plate piece 61. As long as it can be supported, it may be provided anywhere along the axial direction of the rack bar 3.

DESCRIPTION OF SYMBOLS 1 Rack and pinion type steering device 2 Pinion 2a Pinion tooth 3 Rack bar 3a Rack tooth 3b Convex surface 4 Gear case 6 Rack guide 61a Concave surface (sliding support surface)
63 Inclined surface

Claims (4)

A rack guide that supports a rack bar that meshes with a pinion pivotally supported by a gear case via rack teeth, and is movable in the axial direction.
A convex surface on the opposite side of the rack bar on which the rack teeth are formed, and a concave sliding support surface that is slidably in contact with the rack bar;
In the sliding support surface,
Only at the edges of both sides located on both sides in the direction orthogonal to the moving direction of the rack bar and the axial center direction of the rack guide,
An inclined surface that is gradually inclined in a direction away from the rack bar is formed toward the end portion on the moving direction side ,
The inclined surface is not formed on the edge of the bottom surface located in the range excluding the both side portions,
The bottom surface is formed in a concave shape along the convex surface of the rack bar from one end to the other end in the moving direction of the rack bar .
A rack guide characterized by that. The inclined surface is formed in a crowning shape,
The rack guide according to claim 1, wherein: The inclined surface is formed in an end relief shape,
The rack guide according to claim 1, wherein: A rack guide according to any one of claims 1 to 3 is provided.
A rack-and-pinion type steering device characterized by that.

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