JP2021142809A - Rack and pinion type steering gear unit - Google Patents

Abstract

To provide a rack and pinion type steering gear unit capable of sufficiently restraining a tilting operation of a rack guide by widening a space of the rack guide in the reciprocating direction at a plurality of rack guide tilting restraint parts.SOLUTION: A rack and pinion type steering gear unit includes a rack guide tilting restraint part 19 provided in a contact area with a gear housing 10c at a rack guide 15. The rack guide 15 includes a guide groove 18 abutting to stride an outer-peripheral part of a columnar face shape of a rack shaft 4. A contact area of the rack guide 15 is constituted by a first outer-peripheral area 20 and a second outer-peripheral area 21 except the first outer-peripheral area, facing each other outside of the guide groove 18. The rack guide tilting restraint part 19 is constituted by a first protrusion part 22 provided in a protruding manner in each first outer-peripheral area 20 and a second protrusion part 24 provided in a projecting manner in the second outer-peripheral area 21, and an interval L1 between the first protrusion part 22 and the second protrusion part 24 is formed to be large.SELECTED DRAWING: Figure 2

Description

The present invention relates to a rack and pinion type steering gear unit, and relates to a structure for suppressing tilting motion of a rack guide.

A steering device equipped with a rack and pinion type steering gear unit operates a steering wheel to rotate a pinion shaft, thereby reciprocating and linearly moving a rack shaft that meshes with the pinion shaft to steer the steering wheel via a tie rod. be. In such a rack-and-pinion type steering gear unit, as the pinion shaft rotates, a force acting in a direction in which the pinion shaft and the rack shaft are separated from each other acts, and the rack shaft bends to form the pinion shaft and the rack shaft. The backlash of the meshing portion of the pinion shaft may increase, and a tapping sound may be generated at the meshing portion between the pinion shaft and the rack shaft.

Therefore, a pressing structure is adopted in which the rack teeth of the rack shaft are pressed against the pinion shaft to eliminate backlash at the meshing portion between the pinion shaft and the rack shaft.
This type of pressing structure is accommodated in a gear housing provided in communication with an accommodating portion accommodating a pinion shaft and an accommodating portion accommodating a rack shaft so as to be reciprocally movable in the gear housing, and is housed on the rear end side. It is composed of a rack guide that is urged in the rack axis direction to hold the meshed state of the rack shaft and the pinion shaft by the spring member provided in the above. Further, the rack guide has a columnar region (cylindrical portion) on the rear end side that receives the spring member and a guide groove region (tip portion) on the distal end side that abuts so as to straddle the outer peripheral portion of the cylindrical surface shape of the rack shaft. It is composed of and.

Due to the input from the road surface via the tires and the vibration of the vehicle body itself, a large radial load is applied to the rack shaft in the direction orthogonal to the reciprocating movement direction of the rack guide, and the outer peripheral surface of the rack guide is the gear housing. May generate abnormal noise by directly contacting the inner peripheral surface of the tire. Further, when the pressing force of the rack guide is weak, a tapping sound may be generated on the meshing tooth surface due to backlash.

Patent Document 1 includes a rack guide tilt suppressing unit that suppresses the tilting operation of the rack guide in a contact region of the rack guide with the gear housing. The rack guide tilt restraining portion is configured by providing two annular elastic members (O-rings) on the outer peripheral surface in a protruding shape at intervals in the moving direction of the rack guide, and the rack guide is provided with these two annular elastic members. I was trying to suppress the tilting motion.

However, the rack guide tilt restraining portion made of the annular elastic member is spaced only in the outer peripheral surface of the guide groove region in the rack guide, that is, the columnar region avoiding the region overlapping the rack shaft, in the moving direction of the rack guide. Because they were arranged side by side, it was not possible to take a large interval between them. Therefore, the tilting operation of the rack guide cannot be sufficiently suppressed, and a tapping sound may be generated. In addition, the tip side of the tip portion may be worn due to metal contact.
It should be noted that if the rack guide is increased, the interval between the annular elastic members can be increased, but if the rack guide is increased, the physique of the gear housing will inevitably be increased. Dimensional restrictions are imposed on the rack guide.

Japanese Unexamined Patent Publication No. 2005-41251

The present invention has been made to solve such a problem of the prior art, and the subject thereof is a rack in a plurality of rack guide tilt restraining portions without increasing the size of the rack guide. It is an object of the present invention to provide a rack and pinion type steering gear unit capable of sufficiently suppressing tilting motion of a rack guide by widening the interval in the reciprocating movement direction of the guide.

In order to achieve this object, the first invention reciprocates the rack guide and the rack guide for urging the rack shaft toward the pinion shaft to maintain the meshed state between the rack shaft and the pinion shaft. A gear housing that is movably accommodated and a rack guide tilt suppressing portion provided in a contact area with the gear housing in the rack guide are provided, and the rack guide straddles the outer peripheral portion of the cylindrical surface shape of the rack shaft. It has a guide groove that comes into contact with it in this way.
The contact region of the rack guide is composed of a first outer peripheral region located opposite to each other on the outer side of the guide groove and a second outer peripheral region other than the first outer peripheral region.
The rack guide tilt restraining portion is composed of a first protruding portion provided in a protruding shape in each of the first outer peripheral regions and a second protruding portion provided in a protruding shape in the second outer peripheral region. It is a rack and pinion type steering gear unit that is characterized by its presence.

In the second invention, in the first invention, the first protrusion is one or more independent elastic bodies provided in each of the first outer peripheral regions.
The second protrusion is an annular elastic body provided in the second outer peripheral region, and is a rack and pinion type steering gear unit characterized by being.

A third aspect of the present invention is the first aspect of the present invention, wherein the first protrusion is one or more independent elastic bodies provided in each of the first outer peripheral regions.
The second protrusion is a rack and pinion type steering gear unit characterized by being a plurality of independent elastic bodies independently provided in the circumferential direction in the second outer peripheral region.

According to the present invention, it is possible to sufficiently suppress the tilting motion of the rack guide by widening the interval in the reciprocating movement direction of the rack guide in the plurality of rack guide tilt suppressing portions without increasing the rack guide. An and pinion type steering gear unit could be provided.

It is the schematic which shows the 1st Embodiment of the steering apparatus provided with the rack and pinion type steering gear unit of this invention. It is the schematic cross-sectional view which shows the main part of the steering gear unit in 1st Embodiment. In the rack guide of the first embodiment, (a) is a plan view, (b) is an arrow view in the b direction of (a), (c) is a view in the c direction of (a), and (d) is a perspective view. Is shown. In the rack guide of the second embodiment, (a) is a plan view, (b) is an arrow view in the b direction of (a), (c) is a view in the c direction of (a), and (d) is a perspective view. Is shown. In the rack guide of the third embodiment, (a) is a plan view, (b) is an arrow view in the b direction of (a), (c) is an arrow view in the c direction of (a), and (d) is a perspective view. Is shown. In the rack guide of the fourth embodiment, (a) is a plan view, (b) is an arrow view in the b direction of (a), (c) is a view in the c direction of (a), and (d) is a perspective view. Is shown.

Hereinafter, an embodiment of the rack and pinion type steering gear unit of the present invention will be described with reference to the accompanying drawings.
In this embodiment, an embodiment used in the rack and pinion type steering device shown in FIG. 1 is shown. It should be noted that this embodiment is an embodiment of the present invention, and is not construed as being limited thereto, and the design can be changed within the scope of the present invention.
"First embodiment"

1 to 3 show the first embodiment.
The rack and pinion type steering device 1 shown in FIG. 1 has a steering gear unit 5 including a pinion shaft 3 and a rack shaft 4. The driver rotates the steering wheel 2 to rotate the steering shaft 6 and the intermediate shaft 8.
Then, by rotating the pinion shaft 3 connected to the intermediate shaft 8, the rack shaft 4 that meshes with the pinion shaft 3 is reciprocated and linearly moved, and the steering wheel is steered via the tie rod 9. Reference numeral 7 indicates a universal joint that connects the intermediate shaft 8 to the steering shaft 6 and the pinion shaft 3, respectively.

The steering gear unit 5 is a rack guide that urges the housing 10, the pinion shaft 3, the rack shaft 4, and the rack shaft 4 toward the pinion shaft 3 to maintain the meshed state between the rack shaft 4 and the pinion shaft 3. It is composed of (pressure pad) 15.

The housing 10 includes a rack shaft housing 10a for accommodating an axially intermediate portion of the rack shaft 4, a pinion shaft housing 10b for accommodating the first half of the pinion shaft 3, and a gear housing 10c for accommodating the rack guide 15 so as to be reciprocally movable. It is composed of a pair of mounting flange portions 11 for fixing to the vehicle body. The internal space of the rack shaft housing 10a, the internal space of the pinion shaft housing 10b, and the internal space of the gear housing 10c communicate with each other.

Hereinafter, the characteristic parts of the present invention will be described in detail, and since the design of other configurations can be appropriately changed within the scope of the present invention, detailed description thereof will be omitted.

The gear housing 10c is provided orthogonally to the pinion shaft housing 10b at the intersection region of the rack shaft housing 10a and the pinion shaft housing 10b.

The gear housing 10c is formed in a substantially hollow cylindrical shape as a whole, and the opening on one end side is integrally formed with the pinion shaft housing 10b so as to communicate with each other, and the opening on the other end side is detachably closed by a cover 12.
The internal space accommodates the rack guide 15 and the cover 12 that presses the rear end side of the spring member 13 that urges the rack guide 15 in the four directions of the rack shaft, and the rack guide 15 is housed in the cylindrical axis direction of the gear housing 10c. It is formed in a cylindrical shape having an inner diameter that allows contact movement (reciprocating movement).
As the spring member 13, the most suitable spring member 13 is appropriately selected within the scope of the present invention as long as the rack guide 15 can be urged in the four directions of the rack shaft, and the coil spring shown in the present embodiment is assumed. ing.

The rack guide 15 urges the rack shaft 4 toward the pinion shaft 3 to maintain the meshed state between the rack shaft 4 and the pinion shaft 3, and is located on the rear end side that receives the front end side of the spring member 13. A guide groove 18 having a columnar portion 16 and a cylindrical surface-shaped inner surface that is integrally formed on the tip end side of the columnar portion 16 and abuts so as to straddle the outer peripheral portion of the columnar surface shape of the rack shaft 4 is provided. It is composed of a tip portion 17 and a rack guide tilt suppressing portion 19 that suppresses the tilting operation of the rack guide 15 (see FIGS. 2 and 3). The guide groove 18 is recessed in a cylindrical surface so as to cross the tip end side of the tip end portion 17.

The rack guide tilt restraining unit 19 is provided in the contact area of the rack guide 15 with the gear housing 10c (see FIG. 2).
The contact region of the rack guide 15 is a second outer circumference other than the first outer peripheral region 20 forming the outer circumference of each of the tip portions 17 provided with the guide groove 18 and the first outer peripheral region 20 forming the outer circumference of the columnar portion 16. It is composed of a region 21 and.

The rack guide tilt restraining portion 19 includes a first protruding portion 22 provided in a protruding shape in the first outer peripheral region 20 of each tip portion 17 of the rack guide 15, and a second outer peripheral region of the columnar portion 16 of the rack guide 15. It is composed of a second protrusion 24 provided in a protrusion shape at 21 (see FIGS. 2 and 3).

The first protruding portion 22 is an independent elastic body provided by being fixed to a mounting hole portion 23 recessed in a hemisphere in the first outer peripheral region 20 of each tip portion 17.
The mounting hole portions 23 are provided at the maximum diameter position of the first outer peripheral region 20 of each of the tip portions 17, facing each other and having the same depth one by one.
The independent elastic body is an elastic body having a spherical tip portion located at least outward, and in the present embodiment, when housed in the gear housing 10c, it is projected to such an extent that it can be pressed with a predetermined tightening allowance. It is assumed that the entire housing is a spherical elastic body.
Further, the spherical elastic bodies of the present embodiment are all assumed to have the same form. The first protrusion 22 is preferably disposed at a position close to the tip end side of the tip end portion 17 as long as the mounting hole portion 23 is recessed and within a range in which no particular problem occurs in terms of strength.

The second protrusion 24 is an annular elastic body provided in the second outer peripheral region 21 of the columnar portion 16. In the present embodiment, an annular mounting groove 25 continuous in the circumferential direction is recessed at a position close to the rear end side of the second outer peripheral region 21 of the columnar portion 16, and is fixed to the annular mounting groove 25 in a protruding shape to form a gear. It is assumed that the O-ring is projected to the extent that it can be pressed with a predetermined tightening allowance when it is housed in the housing 10c.

Since the spherical elastic body forming the first protrusion 22 has a smaller volume than the O-ring forming the second protrusion 24, the urging force can be balanced by increasing the tightening allowance. Therefore, in the present embodiment, the first protrusion (spherical elastic body) 22 is configured to protrude from the second protrusion 24 (O-ring) (see FIG. 3).

According to the present embodiment, since the first protrusion 22 can be provided in the first outer peripheral region 20 of each tip portion 17, that is, the region overlapping the rack guide 15, the first protrusion 22 can be provided in the moving direction of the rack guide 15. The distance (distance) L1 between the protrusion 22 and the second protrusion 24 can be increased.
As a result, the conventional tilting (rotational moment with the middle of the first protrusion 22 and the second protrusion 24 provided at intervals in the moving direction of the rack guide 15 as a fulcrum) generated in the rack guide 15 is conventionally caused. Since the lever ratio can be increased (increasing the fulcrum force) and the tilting operation of the rack guide 15 (ramp of the rack guide 15) can be suppressed as compared with the technology, it is possible to suppress the tapping sound.

Since the first protrusion 22 merely fixes the spherical elastic body to the mounting hole 23 that is hemispherically recessed in the first outer peripheral region 20 of the rack guide 15, the mounting hole 23 can be easily machined. Is.
Further, since a spherical elastic body is assumed, it is not necessary to consider the directionality at the time of mounting, and the manufacturing / assembling time can be shortened.
"Second embodiment"

FIG. 4 shows a rack guide 15 adopted in the second embodiment of the present invention. Since the configuration of the rack guide 15 is the same as that of the first embodiment, the description of the first embodiment is incorporated.

The first protruding portion 22 is an independent elastic body provided by being fixed to a mounting hole portion 23 recessed in a hemisphere in the first outer peripheral region 20 of each tip portion 17. The independent elastic body is assumed to be the same spherical elastic body as in the first embodiment.
The mounting hole portions 23 are provided one by one at the same depth at positions evenly separated in the circumferential direction from the maximum diameter position of the first outer peripheral region 20 of each tip portion 17. That is, two first protrusions 22 are provided on each of the tip portions 17, and a total of four first protrusions 22 are provided so as to face each other.

The second protrusion 24 is assumed to have an O-ring as in the configuration of the second protrusion 24 of the first embodiment.

According to the present embodiment, the arrangement quantity and arrangement position of the first protrusion 22 are different from those of the first embodiment, and tilting can be suppressed in a well-balanced manner with respect to input from each direction. .. Other configurations and effects are the same as in the first embodiment.
"Third embodiment"

FIG. 5 shows a rack guide 15 adopted in the third embodiment of the present invention. Since the configuration of the rack guide 15 is the same as that of the first embodiment, the description of the first embodiment is incorporated.

The first protrusion 22 adopts the same configuration as that of the second embodiment, and is provided by being fixed to a mounting hole portion 23 recessed in a hemisphere in the first outer peripheral region 20 of each tip portion 17. It is an independent elastic body. The independent elastic body is assumed to be the same spherical elastic body as in the first embodiment.
The mounting hole portions 23 are provided one by one at the same depth at positions evenly separated in the circumferential direction from the maximum diameter position of the first outer peripheral region 20 of each tip portion 17. That is, a total of four first protrusions 22 are provided, two at each tip 17.

The second protrusion 26 in the present embodiment does not use an O-ring like the second protrusion 24 of the first embodiment and the second embodiment. That is, in the present embodiment, a plurality of independent elastic bodies provided independently in the circumferential direction in the second outer peripheral region 21 are used as the second protrusion 26.

The second protrusion 26 is provided in a protrusion shape at the same position as the first protrusion 22 in the moving direction of the rack guide 15. That is, four second protrusions 26 are provided in the circumferential direction of the second outer peripheral region 21 of the columnar portion 16. The spherical elastic body of the second protrusion 26 is assumed to be the same as the spherical elastic body of the first protrusion 22, and is a mounting hole recessed in a hemisphere in the second outer peripheral region 21 of the columnar portion 16. It is provided by being fixed to the portion 27.
The mounting hole portions 27 are provided one by one at the same depth on the same line as the mounting hole portion 23 in the moving direction of the rack guide 15. That is, two second protrusions 26 are provided so as to face each other, like the first protrusions 22 provided at the respective tip portions 17, for a total of four. The independent elastic body constituting the second protrusion 26 is assumed to be the same spherical elastic body as the first protrusion 22.

Since the input to the area overlapping the rack shaft is large, it is configured to balance by increasing the tightening allowance in this area. For example, in the present embodiment, the protrusion amount of the first protrusion 22 is increased by making the recessed depth of the mounting hole 23 for mounting and fixing the spherical elastic body of the first protrusion 22 shallower. With this configuration, the protruding height of the first protruding portion 22 is set higher than the protruding height of the second protruding portion 26, so that the tightening allowance can be increased.
With this configuration, the spherical elastic body of the first protrusion 22 and the second protrusion 26 can be made common, inventory control can be facilitated, and the cost can be reduced. Other configurations and effects are the same as those of the first embodiment and the second embodiment.
"Fourth embodiment"

FIG. 6 shows a rack guide 15 adopted in the fourth embodiment of the present invention. Since the configuration of the rack guide 15 is the same as that of the first embodiment, the description of the first embodiment is incorporated.

The first protrusion 22 is assumed to be an independent elastic body (spherical elastic body) having a diameter slightly larger than that of the first protrusion 22 shown in the first to third embodiments. By increasing the diameter of the spherical elastic body of the first protrusion 22 in this way, the amount of protrusion of the first protrusion 22 is increased and the tightening allowance of the first protrusion 22 is increased.

Similar to the third embodiment, the second protrusion 26 is another embodiment in which a plurality of independent elastic bodies provided independently in the circumferential direction in the second outer peripheral region 21 are used as the second protrusion. be. The independent elastic body constituting the second protrusion 26 is assumed to be the same spherical elastic body as the second protrusion 26 of the third embodiment.

The second protrusion 26 is provided in a protruding shape at the same position as the first protrusion 22 in the moving direction of the rack guide 15, and the cutout region of the guide groove 18 in the moving direction of the rack guide 15. It is composed of those provided in a protruding shape on the same line as the deepest part of the.
That is, four second protrusions 26 are provided in the circumferential direction of the second outer peripheral region 21 of the columnar portion 16 so as to face each other in the circumferential direction of the second outer peripheral region 21 of the columnar portion 16. Therefore, it is provided by being fixed to each mounting hole 27 which is recessed in a hemisphere every 90 degrees. That is, a total of four second protrusions 26 of the present embodiment are provided so as to face each other.
The mounting hole portions 27 are provided in the second outer peripheral region 21 of the columnar portion 16 in the moving direction of the rack guide 15, on the same line as the mounting hole portion 23, and at the same depth. In the moving direction of the rack guide 15, one is provided at the same depth on the same line as the deepest portion of the cutout region of the guide groove 18.

As a matter of course, it is also possible to adopt a spherical elastic body having the same diameter as that of the first embodiment for the first protrusion 22. In this case, by making the recessed depth of the mounting hole 23 for mounting and fixing the spherical elastic body of the first protrusion 22 shallow, the amount of protrusion of the first protrusion 22 is increased, and the first protrusion 22 It is possible to balance by increasing the tightening allowance. Other configurations and effects are the same as those in the first to third embodiments.

The arrangement quantity of the spherical elastic body in each of the above-described embodiments is not particularly limited, and the optimum arrangement quantity can be appropriately selected within the scope of the present invention.

The mounting holes 23 and 27 are not limited to those recessed in a hemisphere, and may be recessed in a cylindrical shape, for example, and the design can be changed within the scope of the present invention. Is.
Instead of the spherical elastic body, the first protrusion 22 and the second protrusion 26 can also be a columnar elastic body having a spherical tip as a protruding portion or an elliptical elastic body. .. Further, the first protrusion 22 and the second protrusion 26 are not limited to those having a spherical tip, and may be projected from the mounting holes 23 and 27 at a predetermined height as long as they are projected from the mounting holes 23 and 27. The design can be changed within the range.

The present invention can be adopted by other than the steering device shown in the present embodiment.

3 Pinion shaft 4 Rack shaft 10c Gear housing 15 Rack guide 18 Guide groove 19 Rack guide tilt suppression part 20 First outer peripheral area 21 Second outer peripheral area 22 First protrusion 24, 26 Second protrusion

Claims (3)

A rack guide that urges the rack shaft toward the pinion shaft to hold the meshed state between the rack shaft and the pinion shaft, a gear housing that accommodates the rack guide so as to be reciprocally movable, and the gear in the rack guide. The rack guide includes a rack guide tilt suppressing portion provided in a contact area with the housing, and the rack guide has a guide groove that abuts so as to straddle the outer peripheral portion of the cylindrical surface shape of the rack shaft.
The contact region of the rack guide is composed of a first outer peripheral region located opposite to each other on the outer side of the guide groove and a second outer peripheral region other than the first outer peripheral region.
The rack guide tilt restraining portion is composed of a first protruding portion provided in a protruding shape in each of the first outer peripheral regions and a second protruding portion provided in a protruding shape in the second outer peripheral region. A rack and pinion type steering gear unit characterized by being. The first protrusion is one or more independent elastic bodies provided in each of the first outer peripheral regions.
The rack and pinion type steering gear unit according to claim 1, wherein the second protrusion is an annular elastic body provided in the second outer peripheral region. The first protrusion is one or more independent elastic bodies provided in each of the first outer peripheral regions.
The rack and pinion type steering gear unit according to claim 1, wherein the second protrusion is a plurality of independent elastic bodies independently provided in the circumferential direction in the second outer peripheral region. ..

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