JPH06239245A - Rack-pinion type steering device - Google Patents

Abstract

PURPOSE:To simplify the forming die of a rack supporting member so as to decrease the cost by interposing at least three elastic members between the rack supporting member and a holding hole, and constructing the grooves for inserting the elastic members so as to be arranged along the width direction of the rack supporting member. CONSTITUTION:At least three elastic members 31a-31d are provided in the circumferential direction between a rack supporting member 16 made by sintering and a holding hole 15 provided in a housing 5. Grooves 30a-30d for inserting the elastic members 31a-31d are formed, the grooves 30a-30d are constructed so as to be arranged along the width direction of the supporting member 16, and hence at sintering the die can be drawn from one piece opening forming die. Further, the elastic members 31a-31d are formed long in the width direction, and hence movement of the rack supporting member 16 can be restrained by at least the three pieces so as to reduce assembling manhours. The elastic members 31a-31d can be arranged outside a rack supporting recessed part 16b without interferring with a rack 7 at the one-side ends, and impact sound between the rack supporting member 16 and the holding hole 15 can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a rack support structure in a rack and pinion type steering device.

[0002]

2. Description of the Related Art A rack and pinion type steering device 100 shown in FIG. 4 is a pinion 101 which is rotated by steering.
A rack 102 that meshes with the pinion 101, a housing 103 that covers the rack 102, and a cylindrical outer peripheral surface that is movably inserted in a holding hole 104 provided in the housing 103 in the axial direction (left and right direction in the drawing). Rack support member 105, which is a surface, and this rack support member 1
And a spring 106 that presses 05 onto the back surface of the rack 102. A rack supporting concave portion 105b that opens at one axial end of the rack supporting member 105 is formed, and the rear surface side of the rack 102 is supported by the concave portion 105b.

By the axial movement of the rack supporting member 105, the bending of the rack 102 and the meshing error between the pinion 101 and the rack 102 are absorbed, and the pinion 10 is absorbed.
1 and the rack 102 mesh smoothly. A gap δ for absorbing thermal expansion between the rack support member 105 and the rack housing 103 is provided between the outer circumference of the rack support member 105 and the inner circumference of the holding hole 104. Further, in order to reduce the size of the device, the axial distance W between the rack support member 105 and the closing portion 108 of the holding hole 104 is set to the rack support member 10.
5 is made as small as possible without restricting the allowable axial movement of No. 5, while the rack support member 105 is formed with an insertion hole 105a opening at the other end in the axial direction, and the spring 106 is inserted in the insertion hole 105a. The insertion space secures a space for disposing the spring 106.

If there is the above-mentioned gap δ between the outer circumference of the rack supporting member 105 and the inner circumference of the holding hole 104,
The rack 102 swings in the radial direction (vertical direction in the drawing) due to the reaction force acting from the road surface via the wheels, and therefore the rack support member 105 is also displaced in the radial direction and tilted. If the radial movement of the rack support member 105 is not regulated at all, the outer periphery of the rack support member 105 and the inner peripheral surface of the holding hole 104 collide with each other, and a large collision sound is generated.

Therefore, the rack supporting member 105 and the holding hole 1
04, an annular elastic member such as an O-ring 110 is interposed, and the O-ring 110 restricts the radial movement of the rack support member 105 (Japanese Patent Laid-Open No. 6847/55).
No. 2). When the O-ring 110 is interposed between the rack supporting member 105 and the holding hole 104, it is necessary to form a circumferential groove on the outer circumference of the rack supporting member 105 or the inner circumference of the holding hole 104. However, forming the peripheral groove on the inner periphery of the holding hole 104 requires time and labor for processing. for that reason,
A peripheral groove 105c is formed on the outer periphery of the rack supporting member 105,
An O-ring 110 is inserted in the circumferential groove 105c.

[0006]

In order to reduce the cost, the rack supporting member 105 is integrally formed by sintering, and the simplest one-piece mold including a fixed mold and a movable mold is used. Molding is desired. However, when the peripheral groove 105c for inserting the O-ring and the spring insertion hole 105a are formed, the rack supporting member 105 can be removed from the single-die forming die in both the axial direction and the radial direction. Will not be possible. Therefore, there is a problem that the peripheral groove 105c needs to be machined or sintered by a complicated forming die, which increases the manufacturing cost.

Further, if the number of O-rings 110 is small, the inclination regulating area of the rack supporting member 105 becomes small.
Many O-rings 110 are required. Therefore, there is a problem that the man-hours for assembling the O-ring 110 and the material cost increase.

The rack supporting member 105 and the holding hole 10 are also provided.
Since the collision with the rack 4 is based on the radial swing of the rack 102, it is most effective to restrict the movement of the rack supporting member 105 at the radially outer position of the rack supporting recess 105b. However, it is not possible to arrange the O-ring 110 radially outward of the rack supporting recess 105b.
It is impossible because it interferes with 02. Therefore, there is a problem that the collision sound cannot be reduced most effectively.

An object of the present invention is to provide a rack and pinion type steering device which can solve the above-mentioned problems of the prior art.

[0010]

A feature of the present invention is that a pinion that rotates by steering, a rack that meshes with the pinion, a housing that covers the rack, and a holding hole provided in the housing are provided with a gap. An outer peripheral surface of the sintered rack support member, which is inserted so as to be movable in the axial direction, is a cylindrical surface, and a spring for pressing the rack support member against the back surface of the rack. In a rack and pinion type steering device in which a rack supporting recess opened on the side and a spring insertion hole opened on the other end in the axial direction are formed, at least three rack pinion members are circumferentially spaced on the outer periphery of the rack support member. Groove is formed along the axial direction, an elastic member elongated in the axial direction is inserted into each groove, and each elastic member contacts the inner surface of each groove and the inner peripheral surface of the holding hole. Located in. It is preferable that at least a part of one end of the elastic member is located radially outward of the rack supporting recess.

[0011]

According to the structure of the present invention, the radial movement of the rack support member can be regulated by the elastic members interposed between the rack support member and the holding hole in the circumferential direction at least three. it can.

Since the groove for inserting each elastic member is along the axial direction of the rack supporting member, even if the rack supporting member has a groove for inserting the elastic member and an insertion hole for the spring, it is formed by sintering. When integrally molding, it is possible to perform die cutting in the axial direction from a single-die forming die.

Since each elastic member is long in the axial direction, if there are at least three elastic members, the area for restricting the radial movement of the rack supporting member can be sufficiently secured, and the man-hours for assembling each elastic member and the material cost can be reduced.

Further, since each elastic member is along the axial direction of the rack supporting member, one end thereof can be arranged radially outside the rack supporting concave portion without interfering with the rack, and the elastic member can be arranged in the radial direction of the rack. The collision noise between the outer circumference of the rack support member and the inner circumference of the holding hole due to the runout can be most effectively reduced.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

The rack and pinion type steering device 1 shown in FIGS. 1 and 2 has an input shaft 2 connected to a steering wheel, a helical pinion 6 integrated with the input shaft 2, and a helical gear meshing with the pinion 6. Rack 7
Aluminum die-cast housing 5 that covers this rack 7.
It has and. The input shaft 2 is supported by the housing 5 via bearings 3 and 4. A tubular screw member 10 is screwed between the input shaft 2 and the housing 5, and the screw member 10 prevents the input shaft 2, the bearings 3, 4, and the pinion 6 from moving in the axial direction. An oil seal 11 is interposed between the input shaft 2 and the input shaft 2. Figure 2
As shown in, the rack 7 protruding from one side of the housing 5 is covered with a cylinder tube 8, and the cylinder tube 8 is press-fitted into a cylindrical portion 5 a formed at one end of the housing 5. Steering wheels are connected to both ends of the rack 7 via tie rods and knuckle arms.
As a result, when the input shaft 2 is rotated by operating the handle, the rotation of the pinion 6 causes the rotation of the pinion 6 to be transmitted to the rack 7, whereby the rack 7 moves in the vehicle width direction. The vehicle is steered by transmitting the movement of the rack 7 in the vehicle width direction to the steering wheels.

A holding hole 15 that opens to the left in FIG. 1 is formed in the housing 5, and a sintered support yoke (rack support member) 16 having an outer peripheral surface of a cylindrical surface is formed in the holding hole 15 in the axial direction ( It is inserted so as to be movable in the left-right direction in FIG. The support yoke 16 is formed with a rack supporting recess 16b which opens at one end side in the axial direction (right side in FIG. 1), and the rack 7 is formed in this recess 16b.
The back side of is supported. The opening on the left side of the holding hole 15 is closed by a plate (closing portion) 18 attached to the housing 5 with a bolt 17. The cylindrical body 20 penetrating the plate 18 is the support yoke 16
Is inserted into the spring insertion hole 16a which is open at the other end in the axial direction. A flange 20a is formed on the cylindrical body 20, and a plate 23 and a compression coil spring 24 are inserted into the spring insertion hole 16a. The spring 24 is the flange 2
The support yoke 16 is pressed against the rack 7 by the elastic force generated by being compressed between the plate 0a and the plate 23. By the axial movement of the support yoke 16,
The machining error of the teeth of the rack 7 and the bending of the rack 7 are absorbed, and the engagement between the rack 7 and the pinion 6 is smoothed.

A screw shaft 21 is screwed onto the tubular body 20, and the axial movement range of the support yoke 16 is restricted by the contact between the screw shaft 21 and the plate 23, so that the pinion 6 and the rack 7 are meshed with each other. Has been done. In order to adjust the screwing amount of the screw shaft 21 into the tubular body 20, a tool insertion recess 21a is formed in the end surface of the screw shaft 21, and a lock nut 22 is screwed onto the screw shaft 21. Further, in order to downsize the device, the support yoke 16
The axial distance W between the plate 18 and the plate 18 is
6 is made as small as possible within the range where the allowable axial movement of 6 is not restricted, while the spring insertion hole 16a is formed in the support yoke 16 to secure a space for disposing the spring 24.

The outer periphery of the support yoke 16 and the holding hole 1
A gap δ for absorbing thermal expansion of the support yoke 16 and the rack housing 5 is provided between the support yoke 16 and the rack housing 5.

As shown in FIG. 3, four grooves 30 are provided on the outer periphery of the support yoke 16 at equal intervals in the circumferential direction.
a, 30b, 30c and 30d are formed along the axial direction. The ends of the grooves 30a, 30b, 30c, 30d are closed on the rack 7 side and the plate 18 is closed.
It is open on the side. Each groove 30a, 30b, 30
c, 30d with elastic members 31a, 31b, 31c, 31d
Has been inserted. Each elastic member 31a, 31b, 31
The c and 31 d have a columnar shape whose axial dimension is longer than the diameter, and are in contact with the inner surfaces of the grooves 30 a, 30 b, 30 c, and 30 d and the inner peripheral surface of the holding hole 15, so that the rack housing 5
And a margin for the support yoke 16. In addition,
Each elastic member 31a, 31b, 31c, 31d is provided in each groove 30.
It may be simply fitted into a, 30b, 30c, 30d, or may be fixed via an adhesive. Each elastic member 31a, 31
The material of b, 31c and 31d may be rubber or synthetic resin. In addition, each elastic member 31a, 31b, 31
In order to reduce the friction between the c and 31d and the inner peripheral surface of the holding hole 15 to facilitate the axial movement of the support yoke 16, lubrication may be performed with grease or the like. Two grooves 30
a, 30b and one end of each of the elastic members 31a, 31b are radially outward of the rack supporting recess 16b (upper and lower sides in FIG. 1).
, The other two grooves 30c and 30d and the elastic member 31.
One end of each of c and 31d is located closer to the plate 18 than the rack 7 so as not to interfere with the rack 7.

According to the above construction, the radial movement of the support yoke 16 is restricted by the elastic members 31a, 31b, 31c, 31d which are interposed between the support yoke 16 and the holding hole 15 at intervals in the circumferential direction. can do.

Each elastic member 31a, 31b, 31c, 31
Since the grooves 30a, 30b, 30c, 30d for inserting d are along the axial direction of the support yoke 16, the support yoke 1
6 is a groove 30a, 30b, 30c, 30d and a spring insertion hole 1
6a, it is possible to perform axial die cutting from a single-die forming die when integrally forming by sintering.

Each elastic member 31a, 31b, 31c, 31
Since d is long in the axial direction, if there are four, a sufficient area for restricting the radial movement of the support yoke 16 due to the twist of the rack 7 can be secured, and each elastic member 31a, 31b, 3
The man-hours for assembling 1c and 31d and the material cost can be reduced.

Further, one end of each of the two elastic members 31a and 31b does not interfere with the rack 7 and the rack supporting recess 16 is provided.
It can be arranged radially outward of b, and the outer circumference of the support yoke 16 and the holding hole 1 due to the radial deflection of the rack 3
It is possible to most effectively absorb the sound of collision with the inner circumference of No. 5.

The present invention is not limited to the above embodiment. For example, the number of elastic members is not limited to four and may be at least three, and the elastic member is not limited to a cylindrical shape and may be elongated in the axial direction. By making it into a curved surface, the contact state with the inner peripheral surface of the holding hole becomes linear contact, the friction between the outer periphery of the elastic member and the inner peripheral surface of the holding hole is minimized, and the rack support member smoothly moves in the axial direction. It can be moved.

[0026]

According to the rack and pinion type steering device of the present invention, when the collision noise between the rack supporting member and the holding hole is reduced, the molding die of the sintered rack supporting member is simplified and the manufacturing cost is reduced. In addition, the number of elastic members required to sufficiently reduce the collision noise can be reduced as compared with the case where an annular member such as an O-ring is used, and the number of assembling steps and the material cost can be reduced. Further, by arranging each elastic member at a position most suitable for reducing the collision noise, noise generation can be effectively prevented.

[Brief description of drawings]

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

FIG. 2 is a front view of a rack and pinion type steering device according to an embodiment of the present invention.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a sectional view of a conventional rack and pinion type steering device.

[Explanation of symbols]

 5 Housing 6 Pinion 7 Rack 15 Holding Hole 16 Support Yoke (Rack Support Member) 16a Spring Insertion Hole 16b Rack Support Recess 24 24 Spring 30a, 30b, 30c, 30d Groove 31a, 31b, 31c, 31d Elastic Member

Claims (2)

[Claims] 1. A pinion that rotates by steering, a rack that meshes with the pinion, a housing that covers the rack, and an outer peripheral surface that is inserted in a holding hole provided in the housing so as to be axially movable. Is provided with a sintered rack support member having a cylindrical surface, and a spring for pressing the rack support member against the back surface of the rack, and the rack support member has a rack support recess opened at one axial end and the other axial end. In a rack and pinion type steering device in which a spring insertion hole that is opened in the axial direction is formed, at least three grooves are formed along the axial direction on the outer periphery of the rack support member at intervals in the circumferential direction. A rack-and-pinion steering system characterized in that a long elastic member is inserted in the axial direction, and each elastic member contacts the inner surface of each groove and the inner peripheral surface of the holding hole. apparatus. 2. The rack and pinion type steering device according to claim 1, wherein at least one end of the elastic member is located radially outward of the rack supporting recess.