JPH10258746A - Pack pressing device for steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent heavy steering and the wearing of an meshing part even if a rack guide for press-supporting the rack bar of a steering device is inclined. SOLUTION: A pinion 11 rotatably supported in a housing 10 is meshed with the rack tooth 16a of a rack bar 16 supported so as to be movable in an axial direction. A rack guide 20 divided into two halves 20A and 20B is supported so as to be movable in an axial direction orthogonal to the respective axial directions of the rack bar and the pinion, a spring 3 brings the seat 25 of a rack guide tip into contact with the rack bar 16 via a spacer 30 contacted simultaneously with the halves and the rack tooth is pressed into the pinion without any backlash. A spherical projecting part 32 is formed in the backside center of the spacer, the tip surface of a stopper part 33 provided to a position- adjustable abuts on this projecting part, thereby regulating the retreating of the rack guide against the spring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for pressing a rack of a rack and pinion type steering device against a pinion.

[0002]

2. Description of the Related Art In a rack and pinion type steering device,
For example, as shown in FIG. 4, a pinion 11 is rotatably supported by the housing 10, and a rack bar 16 having a rack bar 16 meshing with the pinion 11 is supported so as to be movable in the axial direction, and the rotation of the steering wheel is applied to the pinion 11. The rack bar 16 is transmitted and converted into the axial movement of the rack bar 16.
The left and right steering wheels are steered via tie rods provided at both ends of the steering wheel. The rack guide 20, which is provided in a guide hole 10 a formed in a part of the housing 10 on the rear side of the rack bar 16 so as to be movable in the axial direction, is elastically biased toward the rack bar 16 by a spring 34. The support surface 21 at the tip of the rack bar 16 is brought into contact with the rack bar 16 via the sheet 25, and the rack teeth 16a
Is pressed against the pinion 11, and the pinion 11 and the rack teeth 16 are pressed.
The backlash between the pinion 11 and the rack teeth 16a due to the cutting error a or the bending of the rack bar 16 prevents rattling in steering.

In such a steering device, the rack guide 20 is divided into two halves 20A and 20B which can be separated in a direction orthogonal to the axis including the axis of the rack bar 16 and the spring 34. There is a configuration in which the rack guide 20 is elastically pressed through the spacers 1 that simultaneously contact the portions 20A and 20B. Further, in this type, when the steering force increases, the center of the rack bar 16 provided with the rack guide 20 bends backward and the pinion 1
In order not to cause a problem in the meshing of the rack teeth 16a with the rack teeth 16a,
In the example shown in FIG. 4, a stopper 33 is provided for restricting retraction against the spring 34 at the center of the rack guide 20. The stopper 33 is screwed into the guide hole 10 a and fixed by a lock nut 38. 37A
Is formed at the tip. The amount of retreat until the back surface 3 of the spacer 1 comes into contact with the stopper portion 33 is determined by the clearance S between the back surface 3 of the spacer 1 and the tip end surface of the stopper portion 33. If noise is generated, if it is too small, the steering feeling becomes heavy, and the wear of the pinion 11 and the rack teeth 16a increases. Therefore, the clearance S is adjusted to an appropriate value by loosening the lock nut 38 and rotating the pseudo middle bolt 37A to apply the stopper 33 to the back surface 3 of the spacer 1, and then returning the pseudo middle bolt 37A by a predetermined distance. I have to.

[0004]

In a rack pressing device of a steering device of this type, a guide hole 1 formed in a housing 10 is provided.
Since some clearance is unavoidable between the rack guide 20 and the rack guide 20, as shown in FIG. 5, the rack guide 20 does not move as shown in FIG. May tilt from the position. The inclination of the rack guide 20 in the axial direction can occur in any direction, such as not only in the plane including the axis of the pinion 11 as shown in FIG. 5 but also in the plane including the axis of the rack bar 16.

When such an inclination occurs, the minimum clearance between the back surface 3 of the spacer 1 and the stopper portion 33 is the clearance S2 between the back surface 3 of the spacer 1 and the corner of the distal end surface of the stopper portion 33. (See FIG. 5), spacer 1
The amount of retreat until the back surface 3 of the base member 3 comes into contact with the tip end surface of the stopper portion 33 also becomes this clearance S2, which is smaller than the original clearance S, so that the steering feeling becomes heavy and the wear of the pinion 11 and the rack teeth 16a increases. Problem arises. 4 and 5, the clearance between the guide hole 10a and the rack guide 20 and the rack guide 2
The clearance S for determining the retreat amount of 0 is exaggerated.

Further, since the force from each half 20A, 20B of the rack guide 20 is applied to the pressing surface 2 of the outer periphery of the spacer 1, and the force from the stopper 33 is applied to the back surface 3 inside the spacer 1. A large bending moment is applied in the vicinity of the central portion, and there is a possibility that the spacer 1 is broken and no longer functions. An object of the present invention is to solve each of these problems.

[0007]

A rack pressing device of a steering device according to the present invention comprises a pinion rotatably supported by a housing and transmitting rotation from a steering wheel, and a shaft intersecting with the pinion and being mounted on a housing. A rack bar, which is supported so as to be movable in the direction and both ends are connected to the steering wheel via tie rods and has rack teeth formed at the intermediate portion to mesh with the pinion, and the axial direction of the pinion and the rack bar formed on the housing. A rack guide movably supported by a guide hole having an orthogonal axis, and a rack guide provided in such a direction that a sheet provided at the tip of the rack guide abuts against the rear surface of the intermediate portion of the rack bar and presses the rack teeth against the pinion. And a stopper that can adjust the axial position to restrict retraction against the spring of the rack guide. The rack guide is separated into two halves which can be separated in a direction perpendicular to the plane including the axis of the rack bar and the axis of the rack bar, and the spring elastically urges the rack guide through the spacer which comes into contact with both halves at the same time. The present invention relates to a rack pressing device of a steering device configured to be urged, wherein at least the front end portion has a spherical projection at the center of the back surface of the spacer opposite to the rack bar, and the front end surface of the stopper portion is By contacting the projection, the rack guide is restricted from retreating against the spring of the rack guide.

When the input shaft is rotated by rotating the steering wheel, the rack bar moves in the axial direction and the left and right steered wheels are steered. Even when the axial direction of the rack guide is inclined as shown in FIG. 3 from the original direction orthogonal to the axial directions of the pinion and the rack bar as shown in FIG. The minimum clearance between the protrusion and the tip of the stopper is near the center of the tip of the stopper, so there is not much difference from the original clearance until the protrusion of the spacer comes into contact with the tip of the stopper. Is the clearance, and there is no great difference from the clearance in the original axial direction. The spacer has a cross section 2 by providing a projection at the center.
The next moment increases.

It is preferable that the protrusion of the spacer be sized so that the line of intersection with the back of the spacer is a circle whose extent is slightly smaller than the inner diameter of the spring. If you do this,
The second moment of area of the spacer is sufficiently large.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in FIGS. As shown mainly in FIG. 1, a pair of ball bearings 1 is provided in a housing 10 of the steering device.
The pinion 11 is rotatably supported at both ends via 3. Input shaft 1 integrally formed coaxially with pinion 11
A serration 12a for connecting to a steering shaft rotated by a steering handle is formed at a distal end protruding from the second housing 10. On the input shaft 12 side of the housing 10, a collar 14 for restraining the axial position of the outer race of one of the ball bearings 13 is screwed and fixed by a ring nut 15.
An oil seal 17 for sealing between the two is fixed.

The housing 10 supports a rack bar 16 movably in an axial direction intersecting with the pinion 11. This rack bar 16 has a pinion 11 in the middle of the round bar.
The rack teeth 16a meshing with the tooth portions 11a are formed, and both ends are connected to steering wheels (both not shown) via tie rods. A cylindrical guide hole 10a is formed in the housing 10 on the rack bar 16 side in an axial direction orthogonal to each axis direction of the pinion 11 and the rack bar 16, and the rack guide 20 is movably guided by the guide hole 10a. Supported. The rack guide 20 is separated into two half portions 20A and 20B that can be separated in a direction orthogonal to a plane including the axis of the rack guide 16 and the axis of the rack bar 16.
A semicircular support surface 21 formed to be continuous with the front end of the rack guide 20 including the two halves 20A and 20B on the rack bar 16 side has a hard semicylindrical shape rich in lubricity. It is in contact with the center of the rear surface of the rack bar 16 opposite to the rack teeth 16a via the sheet 25. Although not shown, grooves and protrusions are formed on the outer peripheral surface of the sheet 25 and the support surface 21 of the rack guide 20 so as to engage with each other in the longitudinal direction and the circumferential direction.
A, 20B and the support surface 21 are engaged and connected. The rack bar 16 of the two halves 20A, 20B thus connected is
A cylindrical concave portion 22 is formed on the rear surface opposite to the above, and has a truncated cone-shaped pressure receiving surface 23 having a top on the rack bar 16 side.

The rack guide 2 engaged and connected as described above.
0, the two halves 20A, 20B and the support surface 21
Of the rack bar 16 is pressed by the spring 34 via the spacer 30 so that the inner peripheral surface of the rack bar 16 contacts the rear surface of the intermediate portion of the rack bar 16. As shown in FIGS. 1 to 3, the spacer 30 has a disk shape as a whole, and a pressing surface 31 chamfered in a large arc shape is formed on the rack bar 16 on the entire outer periphery of the main body, and is opposed to the rack bar 16. A spherical projection 32 is formed at the center of the rear surface of the spacer 30 on the side. This protrusion 32 may be at least as long as its tip is spherical,
It is preferable that the radius of the spherical surface be as large as possible so that the circle which is the line of intersection with the back surface of the spacer 30 is a circle slightly smaller than the inner diameter of the spring 34. The spacer 30 is integrally formed by sintering or the like, and is inserted into the concave portion 22 of the rack guide 20 so that the pressing surface 31 simultaneously contacts the pressure receiving surfaces 23 of the two halves 20A and 20B. .

In the embodiment shown in FIG. 1, a guide hole 10a is provided.
Is closed by a cover plate 35 fixed to the housing 10 by bolts 39. A boss portion 36 is formed at the center of the cover plate 35 to protrude inward coaxially with the guide hole 10a. O between
It is sealed in a liquid-tight manner by a ring 40. Boss part 36
A spring 34 disposed coaxially with the outside and interposed between the back surface of the housing 10 and the cover plate 35
Moves the sheet 25 at the tip of the rack guide 20 to the rack bar 1
6 is elastically pressed against the rear surface of the middle portion of the rack bar 16, whereby the middle portion of the rack bar 16 is slightly bent, and the pinion 11 and the rack teeth 1
6a is meshed without backlash regardless of the cutting error or the bending of the rack bar 16.

A middle bolt 37 forming a stopper 33 with its tip is screwed into the screw hole formed coaxially with the boss 36 of the cover plate 35 so as to be axially adjustable in position, and fixed by a lock nut 38. It is supposed to be. As described above, in a state where the rack teeth 16a are engaged with the pinion 11 without backlash by being pressed by the spring 34, the lock nut 38 is loosened and the middle bolt 37 is screwed in so that the distal end surface of the stopper portion 33 is
After contacting the protrusion 32 with the center bolt 37, the middle bolt 37 is returned to provide a predetermined clearance S (see FIG. 2) between the distal end surface of the stopper 33 and the protrusion 32, and the middle bolt 37 is 37 is fixed. In the state where the central portion of the rack bar 16 is bent backward until the steering force increases and the protrusion 32 abuts on the distal end surface of the stopper portion 33, the backlash becomes too small, and the clearance S is reduced, and the steering feeling is reduced. Adjust to an appropriate value in a range that does not cause heavy noise or excessive noise due to excessive backlash.

Next, the operation of the above-described embodiment will be described with reference to FIG.
A description will be given with reference to FIG. In this illustration, the clearance between the guide hole 10a and the rack guide 20 and the clearance S (and S1) for determining the amount of retreat of the rack guide 20 are exaggerated for easy viewing. The stopper portion 33 is formed by a screw hole formed in a guide hole 10a of the housing 10 instead of being formed by the tip of a middle bolt 37 screwed to a cover plate 35 fixed to the housing 10 as in the embodiment of FIG. Is formed by a small diameter portion at the tip of the pseudo middle bolt 37A screwed into. Then, as in the case of FIG. 1, the lock nut 38A is loosened and the pseudo middle bolt 37A is screwed in so that the distal end surface of the stopper 33 comes into contact with the projection 32 of the spacer 30. A predetermined clearance S is provided between the distal end surface of the boss and the projection 32, and the pseudo middle bolt 37A is fixed by the lock nut 38A.

When the steering wheel is rotated to rotate the pinion 11 together with the input shaft 12, the teeth 11a and the rack teeth 16
The rack bar 16 moves in the axial direction by the meshing of a, and the left and right steered wheels are steered. When the axial direction of the rack guide 20 is in the original direction orthogonal to the axial directions of the pinion 11 and the rack bar 16 as shown in FIG. Is a predetermined value as adjusted,
When a large steering force is applied, the center portion of the rack bar 16 bends backward until the projection 32 hits the distal end surface of the stopper portion 33, that is, by the clearance S.

The rack guide 20 may be tilted from its original position shown in FIG. 2 due to a manufacturing error such as bending of the rack bar 16 and friction of each part. As shown in FIG. At the corner of the guide hole 10
When it hits a, the inclination becomes maximum. In this state, the spherical protrusion 3 formed in the center of the back surface of the spacer 30
The minimum clearance S1 between 2 and the distal end surface of the stopper portion 33 is near the center of the distal end surface of the stopper portion 33 and is not so much different from the original clearance S. Therefore, when a large steering force is applied, the center portion of the rack bar 16 bends backward until the projection 32 hits the distal end surface of the stopper portion 33, that is, the clearance S1 that is not much different from the original clearance S. Therefore, the rack guide 20
Of the rack bar 16 becomes small, the steering feeling becomes heavy, and the pinion 11
Therefore, there is no possibility that the wear of the rack teeth 16a increases.

The spacer 30 has a pressing surface 31 on its outer peripheral portion.
The force from each half 20A, 20B of the rack guide 20 is applied, and the force from the stopper 33 is applied to the projection 32 on the rear surface, so that a large bending moment is applied near the center.
However, since the spacer 30 has the protrusion 32 at the center to increase the second moment of area, the bending strength is increased. Therefore, even if a large bending moment is applied near the center, a crack is generated at the center of the spacer 30. There is no fear. In particular, as in the above-described embodiment, if the protrusion 32 of the spacer 30 is formed in such a size that the line of intersection with the back surface of the spacer 30 has a circular shape slightly smaller than the inner diameter of the spring 34, Since the second moment of area is sufficiently large, the risk of the spacer breaking is greatly reduced.

[0019]

As described above, according to the present invention, even when the axial direction of the rack guide is inclined from the original axial direction, the amount of retreat until the protrusion of the spacer comes into contact with the distal end surface of the stopper is reduced. The clearance is not much different from the original clearance. Therefore, the steering feeling does not become heavy, and there is no fear that the wear of the pinion and the rack teeth increases.

Further, since the spacer has an increased second moment of area at the center, the bending strength is increased, and there is no possibility that a crack is generated at the center of the spacer due to the bending moment caused by the force applied from the rack guide and the stopper.

If the protrusion of the spacer is formed in such a size that the line of intersection with the back surface of the spacer becomes a circle whose diameter is slightly smaller than the inner diameter of the spring, the second moment of area of the spacer becomes sufficiently large. The risk of cracking is further reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing the entire structure of a rack pressing device of a steering device according to the present invention.

FIG. 2 is a longitudinal sectional view showing an operation state in which a rack guide of a rack pressing device of a steering device according to the present invention is not inclined.

FIG. 3 is a longitudinal sectional view showing an operating state in which a rack guide of a rack pressing device of a steering device according to the present invention is inclined.

4 is a longitudinal sectional view corresponding to FIG. 2 of a rack pressing device of a steering device according to the related art.

FIG. 5 is a longitudinal sectional view corresponding to FIG. 3 of a rack pressing device of a steering device according to the related art.

[Explanation of symbols]

Reference numeral 10: housing, 10a: guide hole, 11: pinion,
16 rack bar, 16a rack teeth, 20 rack guide, 20A, 20B half, 30 spacer, 32
Projection, 33 ... Stopper, 34 ... Spring.

Claims (2)

[Claims] 1. A pinion rotatably supported by a housing to transmit rotation from a steering wheel, and a pinion intersecting the pinion and supported by the housing so as to be movable in an axial direction, and both ends are steered via tie rods. A rack bar connected to wheels and formed with rack teeth meshing with the pinion at an intermediate portion, and a guide hole formed on the housing and having a guide hole having an axis perpendicular to each axis direction of the pinion and the rack bar. A rack guide provided, and a spring elastically biasing the rack guide in a direction in which a sheet provided at the tip of the rack guide abuts against the rear surface of the intermediate portion of the rack bar and presses the rack teeth against the pinion. A stopper for adjusting an axial position of the rack guide, which restricts retraction of the rack guide against the spring; Is separated into two halves that are separable in a direction perpendicular to the plane including the axis of the rack bar and the axis of the rack bar, and the spring resiliently moves the rack guide through a spacer that abuts the two halves simultaneously. In a rack pressing device of a steering device configured to be biased,
At least the distal end has a spherical projection at the center of the back surface of the spacer opposite to the rack bar, and the distal end surface of the stopper abuts the projection to resist the spring of the rack guide. A rack pressing device for a steering device, wherein the rack pressing device is configured to restrict backward movement. 2. The rack pressing device of a steering device according to claim 1, wherein the projection has a size such that a line of intersection with the back surface of the spacer has a shape of a circle slightly smaller than the inner diameter of the spring.