JPH1035514A - Rack and pinion steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To adjust an inter-shaft distance for correcting backlash between a rack and a pinion by a simple structure and work in a rack and a pinion steering device. SOLUTION: A rack shaft 5 having, a rack 5a engaged with a pinion rotated according to a steering operation is held to be freely slid in the axial direction in the cylindrical space 7a of a steering body 7. An eccentric bearing ring member 31 having, in an eccentric position, a holding hole 31a for holding the rack shaft to be freely slid, is provided in the body cylindrical space so as to be freely rotated. A rotation operating member 32 for rotating the eccentric bearing ring member from the outside is provided in a position in the vicinity of engagement between the rack and the pinion in the body cylindrical space is provided so as to face the rack shaft from the orthogonal direction. A circumferential gear part 33 is provided in the side face part of the eccentric bearing ring member and a small gear 32a engaged with this circumferential gear part is provided in the rotation operating member.

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 shaft support structure having a rack that meshes with a pinion.

[0002]

2. Description of the Related Art A rack-and-pinion type steering device has a rack, and a rack shaft disposed along a lateral direction between left and right front wheels (steering wheels) of an automobile, and meshes with the rack of the rack shaft. And a steering gear including a pinion provided at the tip of the steering handle shaft. Then, the rotational displacement accompanying the steering wheel operation is converted into a linear displacement in the axial direction of the rack shaft, and the front wheel is turned in a desired direction via the steering link mechanism. Such a rack-and-pinion type device is relatively simple in configuration as compared with a steering device of another type, is excellent in that the steering performance and the occupied space are small, and is mounted on various vehicles.

In such a rack and pinion type steering apparatus, a rack shaft having a rack meshing with the pinion is generally supported from the bottom side by a rack supporting structure using a spring as a pressing means. That is, a metal rack support having a guide groove disposed on the bottom surface side of the rack shaft so as to face the pinion and slidably supporting the rack shaft in the axial direction; And a pressing plug called an adjusting plug which is screwed so as to close an outer end of a mounting hole for mounting these rack support components into the steering body.

[0004] Then, by applying a required elasticity to the spring by the rotation adjustment of the presser plug, the backlash between the rack and the pinion is elastically supported so that the backlash between the rack and the pinion becomes substantially zero. When rotated by a steering operation, the backlash obtained by the resilience of the spring can ensure proper engagement between the pinion and the rack.

However, according to the above-described conventional rack supporting structure, not only the number of components is large but the structure is complicated, but also the backlash between the pinion and the rack depends on the elasticity of the spring. For example, when a large overload such as kickback is applied to a rack shaft when traveling on a rough road or the like, a metal called so-called rattle sound is generated between a rack and a pinion or between a rack shaft and a rack support. There was a problem that a tapping sound was generated. Further, in the conventional rack support structure described above, the rack shaft is supported at a portion near one end of the steering body depending on the resilience of a spring, and the other end of the body is used at the time of steering operation or an impact such as kickback. It swings around the support portion of the rack shaft by the rack support bush on the side, which also affects the support portion of the rack support bush, so that it is necessary to secure rigidity in this portion.

As the above-described rack support structure, for example, a structure disclosed in Japanese Utility Model Laid-Open No. 57-24175 is known. In this conventional structure, a rack bearing composed of a double metal cylinder and a rubber bush interposed therebetween is provided in the cylindrical space of the steering body, and the inner cylinder of the rack bearing uses the elasticity of the rubber bush, The support position of the rack shaft with respect to the body is displaced by pressing with an adjusting bolt screwed from a direction perpendicular to the body. Then, the rack is meshed with the pinion so that the backlash is substantially zero by the elastic repulsive force of the rubber bush in the rack bearing,
In addition, the backlash between the pinion and the rack is ensured by the elasticity of the rubber bush, so that rotation can be transmitted.

[0007]

According to the above-mentioned conventional rack and pinion type steering device, the former uses a spring as a pressing means, and the latter uses a rubber bush in a rack bearing. It is elastically supported so that backlash can be obtained between them, so it is difficult to secure the rigidity of the rack shaft and the rack supporting bush that holds the other end of the rack shaft, and it is also possible to prevent impact such as kickback. It is unavoidable to hear the sound when it is received. Further, in the latter device described above, the support accuracy of the rack shaft tends to change due to the deterioration of the rubber constituting the rubber bush, the rack shaft tends to rattle, and the durability is also a problem.

In particular, according to the rack-and-pinion type steering device, as described above, the rack meshing with the pinion is meshed with the spring or the rubber bush by imparting the elasticity thereof, and the backlash is obtained by the elasticity. Therefore, it is difficult to adjust the elasticity provided to these meshing portions. That is, during steering operation, the rack and the pinion are sufficiently meshed and in contact with each other, but during straight running, they are meshed by the resilient force of a spring or the like. There is a problem that noise causes noise. further,
In the case of using the latter rubber bush, the noise is further increased due to the deterioration.

[0009] Such a problem is not limited to a manual rack-and-pinion type steering device, but also applies to a power steering device called a power steering.
It is desired to solve the problem in a rack and pinion type steering device. What is desired in such a rack-and-pinion type steering apparatus is that the structure is simple, the adjustment work and the like are easy, and the appropriate adjustment can be performed. It is desirable to take some measures that can be wiped out.

The present invention has been made in view of such circumstances, and in a rack and pinion type steering apparatus, a proper backlash between a rack of a rack shaft and a pinion is ensured by a simple structure, and a distance between both shafts is secured. It is an object of the present invention to obtain a rack-and-pinion type steering device capable of minimizing the generation of a tapping sound by performing the adjustment in a required state.

Another object of the present invention is to provide a rack and pinion type steering device which can more appropriately adjust the distance between the rack shaft and the pinion in the rack and pinion type steering device described above.

[0012]

In order to meet such a demand, a rack-and-pinion type steering apparatus according to the present invention comprises a rack shaft having a rack that meshes with a pinion that rotates in response to a steering operation, and a steering shaft of a steering body. An eccentric bearing ring member which is slidably held in the axial direction within the cylindrical space and has a holding hole for slidably holding the rack shaft at an eccentric position, wherein the eccentric bearing ring member is provided within the cylindrical space of the steering body. And a rotatable operation member for rotatably operating the eccentric bearing ring member from the outside is provided.

Further, the rack and pinion type steering device according to the present invention is characterized in that an eccentric bearing ring member having a holding hole for slidably holding a rack shaft at an eccentric position is engaged with a rack pinion in a steering body. And rotatably provided in a cylindrical space formed at a position close to the part,
An eccentric bearing ring member is provided in the center of the holding hole provided in the other end of the steering body so as to slidably support the other end of the rack shaft at the center of the cylindrical space of the steering body. And is configured to be eccentric with respect to the center of the rack shaft held by the above.

Here, such a rack and pinion type steering device is provided with a circumferential gear portion on a side surface portion of an eccentric bearing ring member, and a rotating operation member having a small gear meshing with the circumferential gear portion is mounted on a rack. By providing the steering body rotatably so as to face from a direction perpendicular to the axis, adjustment by a simple operation can be performed.

According to the present invention, in the rack-and-pinion type steering apparatus, the eccentric bearing ring member formed by eccentrically forming the holding hole for holding the rack shaft is formed by a cylindrical member of the steering body by an external turning operation member. By rotating and displacing in the space, the center distance between the rack and the pinion, especially the backlash, can be adjusted appropriately, minimizing the occurrence of hitting noise due to external impact,
In addition, the eccentric bearing ring member and the rotation operating member can be fixed in the above-described adjustment state, and thus the rack shaft can be stably slidably held.

According to the present invention, the design median is:
The center of the holding hole on the other end side of the steering body that supports the other end of the rack shaft, that is, the center of the cylinder hole, the center of the cylindrical space of the steering body that holds the eccentric bearing ring member, and the center of the rack shaft are parallel to the rack teeth. It is configured so that At this design median, the respective eccentric directions are set so that the center of the cylinder hole and the center of the rack shaft coincide.

Then, the rack shaft and the eccentric bearing ring member designed at the above-mentioned design median are placed at the center of the rack shaft at the position where the rack teeth are farthest from the pinion, that is, the cylinder of the steering body holding the eccentric bearing ring member. Assembling is performed at a position farthest from the pinion with the center of the shape space interposed therebetween. Furthermore, when adjusting the backlash between the pinion and the rack teeth due to errors such as the distance between the axis of the pinion and the rack, the overball size of the pinion, and the overball height of the rack teeth, the amount of adjustment is adjusted by the eccentric bearing. The amount of eccentricity is set so that the rotation angle of the ring member is approximately ± 45 degrees with respect to the designed central value.

Therefore, according to the present invention, the eccentric bearing ring member for holding the rack shaft in an eccentric state is rotationally displaced within a predetermined angle range in the cylindrical space of the steering body, thereby achieving the above-mentioned distance between the shafts, especially the backlash. Rush adjustment can be performed more appropriately.

The rack shaft having the rack is loosely fitted and inserted into the cylindrical space of the steering body, and is held movably in the axial direction. The eccentric bearing ring member that holds the rack shaft is incorporated at a position on one end side of the steering body and close to a meshing portion with the pinion of the rack. The eccentric bearing ring member has a ring shape as a whole, and a circumferential gear portion is provided on a side surface thereof, and the eccentric bearing ring member is rotatable in the cylindrical space of the steering body, and the movement in the axial direction is restricted. Is provided. Further, a small gear of the rotation operation member is supported by the steering body so as to mesh with the circumferential gear portion so as to face from a direction orthogonal to the rack shaft. The rotation operation member includes a lock nut that functions as a lock unit for applying a pressing force at a predetermined adjustment position and fixing the pressing force.

[0020]

1 (a), 1 (b), 1 (c) to 3 show one embodiment of a rack and pinion type steering apparatus according to the present invention. In this embodiment, FIG. The case of a rack and pinion type steering device for power steering as shown in FIG. 3, that is, a rack and pinion type power steering device will be described. 2 and 3, the reference numeral 1 denotes a power steering main body in the rack and pinion type power steering apparatus. Reference numeral 2 denotes a stub shaft as an input shaft connected to a steering handle (not shown). Reference numeral 3 denotes a pinion shaft connected to the inner end (left end) of the stub shaft 2 via a torsion bar 4. Is provided with a pinion 3a that meshes with a rack 5a on a rack 5 constituting a steering link mechanism (not shown). In addition,
Between these two shafts 2 and 3, there is provided a safety spline portion 6 composed of a projection and a groove as a fail-safe mechanism for allowing relative rotation displacement within a predetermined angle range by torsion of the torsion bar 4.

The torsion bar 4 has an inner end press-fitted into the pinion shaft 3 and an outer end extending through the stub shaft 2 to the outer end (right end) of the shaft 2. The torsion bar 4 is provided at the serration 2a for coupling with the steering handle of the stub shaft 2.
And it is integrally connected by welding means such as full circumference welding. Reference numeral 7 denotes a steering body constituting a power steering body, which is an integral body including a body forming a cylindrical space 7a for slidably holding a valve housing of a rotary flow path switching valve 10 and a rack shaft 5 described later. It has a structure. The two shafts 2 and 3 are rotatably supported by a shaft support that is directly received by a bearing or a body 7 described later, and an oil seal is interposed at an appropriate position.

In this steering body 7, each shaft 2, 3
The rotor 11 and the sleeve 12 that constitute the rotary flow path switching valve 10 are integrally connected to the inner end side of the rotor. It is widely known that the relative rotational displacement of the rotor 11 and the sleeve 12 switches the flow path between the oil pump P and the oil tank T (not shown) and the left and right chambers CL and CR of the power cylinder. It is on the street. In this embodiment, the rotor 11 is formed integrally with the stub shaft 2 side, and the sleeve 12 is formed integrally with the pinion shaft 3 and combined with the torsion bar 4 so as to be relatively rotatable and displaceable. 7 is installed in the valve housing space 8 in the valve housing part.

The construction of the hydraulic circuit in the rotor 11 and the sleeve 12 constituting the rotary flow path switching valve 10 and the hydraulic circuit in the valve housing (body 7) is the same or similar to that widely known. is there. That is, a plurality of passage grooves are formed as valve grooves at predetermined intervals in the circumferential direction on the outer peripheral surface of the rotor 11 and the inner peripheral surface of the sleeve 12 which are in sliding contact with each other. And fluid discharge holes are formed by drilling them at appropriate places, and the hydraulic circuit is switched and controlled as necessary by selectively communicating and blocking these passage grooves and the like.

In the figure, reference numerals 15 and 16 denote inlet ports into which pressure oil flows from the oil pump P and return ports for returning the pressure oil to the oil tank T, and reference numerals 17A and 17B denote left and right cylinder chambers CL and CL of the power cylinder. At the left and right output ports connected to the CR, the hydraulic displacement between these ports is arbitrarily communicated and shut off by the rotational displacement accompanying the steering operation of the flow path switching valve 10 described above. It is also widely known to control the generation of the steering assist force in the vehicle.

In the rotary type flow switching valve 10, the sleeve 12 is provided integrally with the pinion shaft 3.
This pinion shaft 3 is mounted on the steering body 7 at both ends of the sleeve 12 by ball bearings 21 which are rolling bearings.
It is supported by a bush 22. Further, the small-diameter distal end portion 3b of the pinion shaft 3 is slightly larger than the bearing clearance at the shaft support portion by the bearings 21 and 22 at both ends of the sleeve 12 within the allowable bending stress of the pinion shaft 3. The shaft is supported by a bearing structure that is directly received by the steering body 7 by the shaft support portion 23 set as described above.

The above-described ball bearing 21 has a structure in which a small diameter portion formed at the end of the sleeve 12 integral with the pinion shaft 3 is used as an inner ring, and a ball and an outer ring are assembled. In the drawing, reference numeral 25 denotes a plug member which is screwed into the opening end of the mounting space 8 in the steering body 7. The inner end of the plug member 25 is abutted against the outer ring of the ball bearing 21 and is locked between the step portion of the body 7. The plug member 25 has an opening for penetrating and holding the stub shaft 2 and the oil seal 2.
6 are formed. And
The stub shaft 2 is rotatably inserted into the body 7 and sealed by the oil seal 26.
On the other hand, an oil seal 27 is also provided on a portion of the pinion shaft 3 closer to the pinion 3a than the bush 22.

In FIG. 3, reference numeral 41 denotes a metal pipe integrally connected to the other end of the steering body 7 and constituting the cylinder portion 40a of the power cylinder 40 described above. The piston 43 provided on the provided piston rod 42 is supported so as to be able to advance and retreat. Reference numeral 44 denotes a rack supporting bush for slidably supporting a piston rod 42 (the other end of the rack shaft 5) at an extending end of the pipe body 41 on the side opposite to the body 7.

An oil seal 4 for forming the left and right chambers CL and CR of the cylinder 40 is provided inside the bush 44 and at the end on the body 7 side in the pipe body 41.
5, 46 are provided. In FIG. 3, tie rods 48 are provided at both ends of the rack shaft 5 via ball joints 47, and the connecting portions thereof are connected to the bellows-like boots 4.
9, the details are as widely known, and the detailed description is omitted here.

According to the present invention, in the rack-and-pinion type power steering apparatus having the above-described configuration, the rack shaft 5 having the rack 5a meshing with the pinion 3a of the pinion shaft 3 rotated in accordance with the steering operation is connected to the steering shaft. In holding the body 7 slidably in the axial direction in a state of being loosely fitted in the cylindrical space 7a of the body 7, FIG.
As shown in (b), the pinion shaft 3 has a simple structure.
The distance between the two shafts (adjustment of the backlash between the pinion 3a and the rack 5a) is appropriately supported by the rack support portion 30.

That is, according to the present invention, the eccentric bearing ring member 31 having the holding hole 31a for slidably holding the rack shaft 5 at a position eccentric with respect to the axis of the cylindrical space 7a is provided. The rack 5a is rotatably provided in a cylindrical space 7a of the body 7 at a position close to a portion where the rack 5a meshes with the pinion 3a. In addition, a rotation operating member 32 for rotating the eccentric bearing ring member 31 from outside the steering body 7 is provided.

In this embodiment, as shown in FIG. 1A, the above-described eccentric bearing ring member 31 is located in a cylindrical space 7a close to one end of the steering body 7, and is shown in FIG. Are rotatably supported at a position close to a meshing portion between the rack 5a and the pinion 3a. The eccentric bearing ring member 31 has a ring shape as a whole,
It is rotatably held in the body cylindrical space 7a. Further, a circumferential gear portion 33 is formed on the side surface inside the body of the eccentric bearing ring member 31 by a bevel gear. In FIG. 1A, reference numeral 34 denotes a set ring for restricting the eccentric bearing ring member 31 from coming out of the body 7 in the axial direction.

A cylindrical boss 7b projects from a part of the steering body 7 facing the circumferential gear 33 of the eccentric bearing ring member 31, and the boss 7b
A hole 7c facing from a direction perpendicular to the hole 7c is formed. A rotary operation member 32 having a small gear 32a meshing with the circumferential gear portion 33 is inserted into the hole 7c, and is rotatably supported by a shaft. Reference numeral 35 denotes a lock nut, which is screwed into a thread formed on the outer end side of the hole 7c to lock the rotation operation member 32 by applying a pressing force at a predetermined rotation adjustment position.
Reference numeral 6 denotes an O-ring that is interposed between the rotary operation member 32 and the lock nut 35 in a state of being pressed against the hole and used to seal the hole 7c.

In this case, the above-described eccentric bearing ring member 31 and rotation operating member 32 are configured so that rotation can be transmitted by a combination of a bevel gear and a small gear that meshes with the bevel gear, but the present invention is not limited to this. Bevel gear, hypoid gear,
Alternatively, it may be constituted by a rotation transmitting means using a worm wheel. Further, the eccentric bearing ring member 31 described above is used.
It is preferable to use one integrally formed of a sintered metal, but the present invention is not limited to this, and one formed integrally with a bush, resin coating, or resin on the inner diameter of a metal material may be used. In addition, as a fixing means of the rotation operation member 32 described above, an adjuster (small gear) may be pressed and fixed with a screw and may be sealed with an O-ring.

According to such a configuration, the small gear 32 a of the rotation operating member 32 meshing with the circumferential gear 33 provided on the side surface of the eccentric bearing ring member 31 faces from the direction orthogonal to the rack shaft 5. The supporting position of the rack shaft 5 with respect to the pinion 3a can be adjusted by a simple operation of rotating the steering shaft 7 with respect to the steering body 7. Further, since the components such as the circumferential gear portion 33 on the eccentric bearing ring member 31 side, the small gear 32a on the rotary operation member side, and the lock nut 35 can be formed by a mold, the support of the rack shaft 5 is stabilized and the cost is reduced. Are also inexpensive.

That is, the holding hole 3 for holding the rack shaft 5
The eccentric bearing ring member 31, which is formed by eccentrically deviating the cylindrical space 7a from the cylindrical space 7a, is rotationally displaced within the cylindrical space 7a of the steering body 7 by adjusting the rotation of the rotation operation member 32, thereby to set the rack shaft. The backlash between the rack 5a and the pinion 3a can be appropriately adjusted by adjusting the distance between the pinions 5 and the pinion shaft 3. Further, when the lock nut 35 is tightened after this adjustment, the rotation operation member 32 and the eccentric bearing ring member 31 can be locked, so that the rack shaft 5 can be slidably held in a stable state. Therefore, according to such a configuration, the adjustment of the center distance between the rack 5a of the rack shaft 5 and the pinion 3a, that is, the adjustment of the backlash can be reliably performed with a simple structure. If the backlash is properly formed as described above, it is possible to minimize the occurrence of a tapping sound even at the time of impact.

FIGS. 4 and 5 show another embodiment of the present invention. FIG. 4 (a) shows an eccentric bearing ring member 31 and a rack shaft 5 whose rotation can be adjusted in a cylindrical space 7a of the steering body 7. The figure which shows the state of the design median value when designing the center O, R, Q of the cylinder hole (rack support bushing 44), the figure which shows the state at the time of assembly, and the figure which shows the upper limit at the time of adjustment. FIG. 5 is a diagram showing a position state, and FIG. 5 is an explanatory diagram for explaining an adjustment state of an inter-axis distance (backlash) between the pinion and the rack shaft 5.

According to the present invention, the eccentric bearing ring member 31 having the eccentric position of the holding hole 31a for slidably holding the rack shaft 5 is located in the steering body 7 close to the meshing portion with the pinion of the rack. And a center O of the cylindrical space 7a of the steering body 7 is aligned with the rack shaft 5a.
The center Q of the holding hole of the rack supporting bush 44 provided at the other end of the steering body 7 (metal pipe 41) so as to slidably support the other end of the steering shaft 7 and the cylindrical space 7a of the rack shaft 5. It is configured to be eccentric with respect to the center R held through the eccentric bearing ring member 31 inside.

In detail, according to the present invention, FIG.
As shown in (a), at the design median, the center Q of the holding hole (the center of the cylinder hole) on the other end side of the steering body 7 supporting the other end of the rack shaft 5 and the steering holding the eccentric bearing ring member 31. The center O of the cylindrical space 7a of the body 7 and the center R of the rack shaft 5 are parallel to the rack teeth 5a, in other words, the center Q of the cylinder hole and the rack shaft 5
Are set so that their centers R coincide with each other.

Then, the rack shaft 5 and the eccentric bearing ring member 31 designed at such a design median value are connected to each other as shown in FIG.
As shown by R1 in (b), the center of the rack shaft 5 is located at the position where the rack teeth 5a are farthest from the pinion 3a, that is, the center O of the cylindrical space 7a of the steering body 7 holding the eccentric bearing ring member 31. Pinion 3a
The assembly is configured to be performed at a position farthest from the pinion 3.
The work at the time of assembling can be easily performed.

The distance between the pinion 3a and the rack shaft 5, the overball size of the pinion 3a, the rack teeth 5a
When adjusting the backlash between the pinion 3a and the rack teeth 5a due to an error such as the overball height of the eccentric bearing ring member 31, as shown in FIGS. The eccentricity adjustment amount is set so that the rotation angle is approximately ± 45 degrees with respect to the design median. In the drawing, R2 indicates an upper limit position during adjustment, and R3 indicates a lower limit position during adjustment.

Therefore, according to such a configuration, the eccentric bearing ring member 31 for holding the rack shaft 5 in an eccentric state.
Is rotationally displaced in the cylindrical space 7a of the steering body 7, thereby making it possible to more appropriately adjust the inter-axis distance, particularly the backlash. In particular, in the above-described configuration, the displacement in the inter-axis distance direction can be a relatively linear movement with respect to the rotation angle of the eccentric bearing ring member 31, and adjustment can be performed easily and appropriately.

That is, in the above-described configuration, as is apparent from the adjustment range of the center of the rack shaft in FIG. 5, the displacement in the lateral direction of the rack shaft 5, that is, the direction parallel to the rack teeth 5a is "0" in the design median. Even if the position is adjusted to the upper limit or the lower limit, the amount of movement at the time of the adjustment is small. Therefore, the rack shaft 5 which is originally not preferable
The distance between the axes and the backlash can be adjusted while minimizing the lateral movement of the. In particular, this movement amount is significantly smaller than the adjustment amount of the center distance.

For example, with respect to the center O of the cylindrical space 7a of the steering body 7, the center R of the rack shaft 5 at the design median and the center of the holding hole of the rack supporting bush 44 for supporting the other end (the center of the cylinder hole). Center) The amount of eccentricity with Q is set to 0.
When the eccentric bearing ring member 31 is rotated and adjusted within a range of ± 45 degrees from the designed center value when the distance is 3 mm, the amount of movement in the direction parallel to the rack teeth is at most about 0.088 mm, and is almost “0”. Is easily inferred geometrically.

It should be noted that the present invention is not limited to the structure described in the above embodiment, and the shape, structure, etc. of each part in the power steering main body 1 in the rack and pinion type power steering device as the rack and pinion type steering device. May be appropriately modified or changed. For example, in the above-described embodiment, the holding hole 31a for holding the rack shaft 5 is provided at an eccentric position in the eccentric bearing ring member 31 rotatably held in the cylindrical space 7a of the steering body 7. The present invention is not limited to this, and is configured such that an eccentric bearing ring member whose outer peripheral surface is eccentric with respect to the holding hole of the rack shaft is rotatably held in an eccentric hole formed eccentrically on the inner peripheral portion of the body 7. May be.

Further, the shaft supporting structure of the eccentric bearing ring member 31 and the shape of the circumferential gear portion 33 on the side surface, and the small gear 3 meshing therewith
Various modifications are conceivable as the shape of the shaft 2a, the support structure of the rotary operation member 32 having the small gear 32a, and a lock means such as a lock nut 35 for locking the rotation by a pressing force. Furthermore, in the above-described embodiment, the rack-and-pinion type power steering device which is a power steering is described. However, the present invention is not limited to this, and is applied to a rack and pinion type steering device which is a manual steering. Has the same effect.

[0046]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Cylindrical space 7a in steering body 7
In the above, a rack support portion 30 that slidably holds a rack shaft 5 having a rack 5a that meshes with the pinion 3a of the pinion shaft 3 is rotatably provided in the body cylindrical space 7a, and is provided with a snap ring 34 in the axial direction. An eccentric bearing ring member 31 for restricting the movement of the steering body 7 and a rotating operation member 3 rotatably held facing a direction orthogonal to the steering body 7.
2 is configured to be rotatable by a rotation transmitting member 32 including a circumferential gear portion 33 formed by a bevel gear provided on a side surface of the ring member 31 and a small gear 32a meshing with the circumferential gear portion 33.

[0047]

As described above, according to the rack and pinion type steering apparatus of the present invention, the rack shaft having the rack which is disposed in the cylindrical space of the steering body and meshes with the pinion which rotates in accordance with the steering operation is provided. An eccentric bearing ring member having a holding hole slidably held at an eccentric position is rotatably provided at a position close to a meshing portion with a pinion of a rack in the cylindrical space, and the eccentric bearing ring is provided. Since the rotation operation member for rotating the member from the outside is provided, the following advantageous effects can be obtained despite the simple configuration.

According to the present invention, the adjustment of the backlash between the rack and the pinion, that is, the adjustment of the distance between the shafts can be performed by a simple operation using a simple structure of the eccentric bearing ring member and the rotary operation member for rotating and adjusting the ring. And it can do it properly,
This can reduce the occurrence of a tapping sound even when an impact such as kickback occurs. In addition, since the rack shaft can be securely supported by the eccentric bearing ring member without play, it swings around the support portion of the rack supporting bush that supports the other end side of the rack shaft as in the related art. The rigidity of the rack shaft and its supporting portion can be improved, the hammering noise can be prevented, and the durability can be improved.

Further, according to the present invention, since the reduction ratio of the gear in the rotation transmission system is relatively large with respect to the amount of adjustment of the distance between the shafts due to the amount of eccentricity of the eccentric bearing ring member, the adjustment work is facilitated, and the shaft operation is facilitated. The accuracy of the distance can be improved. Further, according to the present invention, since the rotation operating member as the adjusting means and the lock nut as the fixing means are independent of the eccentric bearing ring member, the rotating operation member is securely fixed without disturbing the adjusted position after the adjustment. be able to.

In particular, according to the rack and pinion type steering device of the present invention, the eccentric bearing ring member having the eccentric position of the holding hole for slidably holding the rack shaft is connected to the rack pinion in the steering body. The steering body is rotatably provided in a cylindrical space formed at a position close to the meshing portion, and the center of the cylindrical space of the steering body is slidably supported at the other end of the rack shaft. The center of the holding hole provided on the other end side and the center of the rack shaft are eccentric with respect to the center held by the eccentric bearing ring member in the cylindrical space, so that the following excellent effects can be obtained. .

That is, according to the present invention, at the design median, the center of the holding hole on the other end side of the steering body that supports the other end of the rack shaft, that is, the center of the cylinder hole, the steering body that holds the eccentric bearing ring member is provided. The respective eccentric directions are set so that the center of the cylindrical space and the center of the rack axis are parallel to the rack teeth, in other words, the center of the cylinder hole and the center of the rack axis coincide.

The rack shaft and the eccentric bearing ring member designed with such a design median value are connected to the center of the rack shaft at the position where the rack teeth are farthest from the pinion, that is, the steering body holding the eccentric bearing ring member. By assembling at the position farthest from the pinion across the center of the cylindrical space, the work at the time of assembly can be easily performed.

Further, according to the present invention, the backlash between the pinion and the rack teeth is adjusted by errors such as the axial distance between the pinion and the rack, the overball size of the pinion, and the overball height of the rack teeth. In doing so, the amount of eccentricity is set so that the amount of adjustment is approximately ± 45 degrees with respect to the designed central value in the rotation angle of the eccentric bearing ring member.

Therefore, the eccentric bearing ring member for holding the rack shaft in an eccentric state is rotationally displaced in the cylindrical space of the steering body, whereby the distance between the shafts, particularly, the backlash can be more appropriately adjusted. it can. In particular, in the configuration described above, the displacement in the direction of the distance between the axes can be a relatively linear movement with respect to the rotation angle of the eccentric bearing ring member, and adjustment can be performed easily and appropriately.

Further, according to the present invention, the displacement in the lateral direction of the rack axis, that is, the direction parallel to the rack teeth can be set to “0” in the design median, and the movement of the rack axis in the lateral direction, which is originally unfavorable. Can be adjusted to minimize the distance between axes and backlash. In particular, this movement amount is significantly smaller than the adjustment amount of the center distance.

[Brief description of the drawings]

FIG. 1 shows one embodiment of a rack-and-pinion type steering device according to the present invention, in which (a) is a cross-sectional view of a main part in which a support portion of a rack shaft in a steering body is enlarged.
(B) is a sectional view taken along line II of (a), and (c) is a plan view showing an attached portion of the rotary operation member.

FIG. 2 is a cross-sectional view of a power steering main body in a power steering device to which a rack and pinion type steering device according to the present invention is applied.

FIG. 3 is a cross-sectional view for explaining a power steering main body and a power cylinder in a rack and pinion type steering device for power steering to which the present invention is applied.

FIG. 4 shows another embodiment of the rack-and-pinion type steering device according to the present invention, wherein (a) shows an eccentric bearing ring member that can be rotationally adjusted in a cylindrical space of a steering body, a rack shaft, and the center of a cylinder hole. FIG. 6B is a diagram showing a state of a design median when (a) is designed, (b) is a diagram showing a state at the time of assembly,
(C) is a figure which shows the state of the upper limit position at the time of adjustment.

5 is an explanatory diagram for explaining an adjustment state of an inter-axis distance between a pinion and a rack shaft in the rack and pinion type steering apparatus in FIG. 4;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Power steering main body part in a rack and pinion type power steering device, 2 ... Stub shaft, 3 ... Pinion shaft, 3a
... pinion, 3b ... tip, 4 ... torsion bar, 5 ...
Rack shaft, 5a: rack, 7: steering body, 7
a: cylindrical space, 7b: cylindrical boss, 7c: hole, 8: built-in space, 10: rotary flow switching valve, 11: rotor, 1
2 ... Sleeve, 15, 16 ... Enter port and return port, 17A, 17B ... Left and right output ports, 21 ... Ball bearing (bearing as shaft support), 22 ... Bushing (bearing as shaft support), 23 ... Shaft Support part, 30: rack shaft support part, 31: eccentric bearing ring member, 31a: holding hole, 32: rotary operation member, 32a: small gear, 33: circumferential gear part, 34: set ring, 35: lock nut, 3
6 ... O-ring, 40 ... Power cylinder, 40a ... Cylinder part, 41 ... Metal pipe, 44 ... Rack supporting bush, O ... Center of cylindrical space for holding the eccentric bearing ring member so that rotation can be adjusted, R ... Rack Center of shaft, Q: Center of cylinder hole (center of holding hole in rack supporting bush that slidably holds the other end of rack shaft at the other end of steering body), P: oil pump, T: oil tank ,
CL, CR: Power cylinder left and right chambers.

Claims (4)

[Claims] 1. A rack and pinion type power steering apparatus in which a rack shaft having a rack meshing with a pinion that rotates in accordance with a steering operation is slidably held in a cylindrical space of a steering body in an axial direction. An eccentric bearing ring member having a holding hole for slidably holding the rack shaft at an eccentric position is rotatably provided in the cylindrical space of the steering body, and the eccentric bearing ring member is rotated from the outside. A rack-and-pinion type steering device comprising a rotary operation member for performing a moving operation. 2. The rack and pinion type steering device according to claim 1, wherein an eccentric bearing ring member having a holding hole for slidably holding the rack shaft at an eccentric position is meshed with a rack pinion in the steering body. The steering body is provided so as to be rotatable in a cylindrical space formed at a position close to the steering portion, and the center of the cylindrical space of the steering body is slidably supported at the other end of the rack shaft. Characterized in that the rack and pinion are configured to be eccentric with respect to the center of the holding hole provided at the other end of the rack shaft and the center held via the eccentric bearing ring member in the cylindrical space of the rack shaft. Type steering device. 3. The rotation device according to claim 1, wherein a circumferential gear portion is provided on a side surface of the eccentric bearing ring member, and a small gear meshes with the circumferential gear portion. A rack-and-pinion type steering device wherein an operation member is rotatably provided on a steering body so as to face from a direction orthogonal to a rack axis. 4. The rack and pinion type steering device according to claim 1, wherein the eccentric bearing ring member is located close to a meshing portion between the rack and the pinion in the cylindrical space of the steering body. A rack and pinion type steering device characterized by being provided at a position.