JP4776264B2 - Rack and pinion steering system - Google Patents

Description

  The present invention relates to a rack-and-pinion steering device for a vehicle that transmits a steering force to a steered wheel via a rack shaft provided with a rack that meshes with a pinion.

A rack-and-pinion steering device for a vehicle includes a rack guide that supports a rack shaft provided with a rack so as to be slidable in the axial direction and reduces backlash at a meshing portion between the pinion and the rack. For example, in the rack and pinion type steering device disclosed in Patent Document 1, a support yoke (corresponding to a rack guide) that is accommodated in a housing hole and supports a rack shaft, and the rack shaft is connected to the pinion shaft side via the support yoke. A first coil spring that is biased toward the support member, a receiving member that is slidably received in the support yoke, and a roller that is provided in the receiving member while being accommodated in a ball receiving hole provided in the support yoke. And a second coil spring that urges the ball to abut against the rack shaft via the receiving member. As a result, in the initial movement region (small load region) of the steering operation, the balls are in rolling contact with the rack shaft, so that the movement resistance of the rack shaft is reduced and the steering feeling is improved. Further, when a large load is input, the balls are retracted into the ball receiving holes, and the support yoke firmly supports the rack shaft.
JP 2001-328547 A (FIGS. 3 and 4)

  By the way, in the said prior art, the receiving member, the 2nd coil spring, and ball which comprise the mechanism for pressing a rack axis | shaft with a ball | bowl are separately attached with respect to a support yoke, and the support accommodated in the housing Since the ball, the receiving member, and the second coil spring are sequentially attached to the yoke, the number of steps for assembling the mechanism with respect to the housing increases, and the cost increases accordingly.

  In addition, in order to suppress a phenomenon in which the rack shaft moves due to a disturbance such as a road surface reaction force during vehicle travel (for example, kickback), the urging force of the first coil spring is increased or the rack shaft and the support yoke are The frictional force (friction resistance) from the support yoke acting on the rack shaft may be increased by increasing the friction coefficient. However, when the frictional resistance of the rack shaft is increased, the movement of the rack shaft due to the turning force from the driver becomes dull and the turning feeling is lowered.

  This invention is made | formed in view of such a situation, and the invention of Claims 1-5 aims at the improvement of the assembly | attachment property of a press mechanism provided with an additional press mechanism in a rack and pinion type steering device. For the purpose. The invention described in claims 2 to 4 further aims to improve the assembling property of the additional pressing mechanism to the pressing member, and the invention described in claim 5 further reduces the steering feeling. The purpose is to improve the steerability after restraining, and to make it possible to adjust the balance between turning feeling and steerability.

The invention according to claim 1 is a rack and pinion type steering device for a vehicle that transmits a steering force to a steered wheel via a rack shaft provided with a rack that meshes with a pinion that rotates by a steering force. In the rack and pinion type steering apparatus, the pressing mechanism that presses the pinion toward the pinion includes a pressing member that is assembled to the housing and presses the rack shaft by an urging force. An additional pressing mechanism including an additional biasing member that generates an additional biasing force acting on the rolling element that presses the rack shaft, and the additional pressing mechanism is integrally assembled to the pressing member ; The rolling element is a rack and pinion type steering device provided on the pressing member so as not to drop off .

  According to this, since the additional pressing mechanism is incorporated in the pressing mechanism by assembling the pressing member having the additional pressing mechanism built in the housing in advance, the rolling element and the additional member are added to the pressing member after the pressing member is assembled in the housing. Compared to the case where the urging member is assembled, the number of assembling steps of the pressing mechanism with respect to the housing is reduced, and labor is reduced.

According to a second aspect of the present invention, there is provided a rack-and-pinion type steering device for a vehicle that transmits a steering force to a steered wheel via a rack shaft provided with a rack that meshes with a pinion that is rotated by a steering force. In a rack and pinion type steering apparatus, a pressing mechanism that presses the rack shaft toward the pinion includes a pressing member that is assembled to a housing and presses the rack shaft with an urging force. The pressing mechanism is in rolling contact with the rack shaft. An additional pressing mechanism configured by a rolling element and an additional biasing member that generates an additional biasing force acting on the rolling element that presses the rack shaft, and the additional pressing mechanism is configured as one unit component. the assembled to the pressing member, the rolling element is a rack-and-pinion stearyl provided so as not to fall off the pressing member A ring device.

  According to this, since the additional pressing mechanism is assembled to the pressing member as one component, the number of assembling steps of the additional pressing mechanism with respect to the pressing member is compared with the case where the rolling element and the additional biasing member are separately assembled to the pressing member. Decrease.

  According to a third aspect of the present invention, in the rack and pinion type steering apparatus according to the first or second aspect, the additional urging member is configured by a case that holds the rolling element in a rollable manner.

  According to this, the structure of the additional pressing mechanism is simplified, and the number of parts is reduced.

  According to a fourth aspect of the present invention, in the rack and pinion type steering apparatus according to the second aspect, the pressing member constitutes a contact portion between the main body and the rack shaft of the pressing member, and is a pad assembled to the main body. The additional pressing mechanism is assembled to the pad.

  According to this, in the pressing member having a structure in which the pad is assembled, the additional pressing mechanism is built in the pressing member by assembling the pad in which the additional pressing mechanism is built in the main body in advance, so that the pad is assembled in the main body. Compared to the case where the additional urging member is assembled after this, the number of assembling steps of the additional pressing mechanism with respect to the pressing member is reduced.

  The invention according to claim 5 is the rack and pinion type steering device according to claim 1 or 2, wherein the pressing member and the rolling element are always in contact with the rack shaft in a state where the pressing mechanism is assembled to the housing. Thus, the rack shaft is always pressed.

  According to this, in addition to the urging force acting on the pressing member, the pressing member and the rolling element are always in contact with the rack shaft and constantly pressing the rack shaft in a state where the pressing mechanism is assembled to the housing. The frictional resistance of the rack shaft can be increased by the added urging force. On the other hand, the increase in the frictional resistance due to the additional urging force is based on rolling friction, so that it is suppressed compared to the case of sliding friction. It becomes. Further, the amount of increase in the frictional resistance by the additional pressing mechanism can be adjusted by changing the characteristics defining the forming material of the rolling element or the forming material of the additional biasing mechanism and the biasing force.

  According to invention of Claim 1, the following effect is show | played. That is, since the man-hour for assembling the pressing mechanism with respect to the housing is reduced, the assembling property of the pressing mechanism including the additional pressing mechanism in the rack and pinion type steering device is improved.

  According to invention of Claim 2, the following effect is show | played. That is, since the man-hours for assembling the additional pressing mechanism with respect to the pressing member are reduced, the assembling property of the additional pressing mechanism with respect to the pressing member is improved. Will improve.

  According to invention of Claim 3, in addition to the effect of the invention of the cited claim, there exist the following effects. That is, since the structure of the additional pressing mechanism is simplified, the assembling property of the additional pressing mechanism is improved, and the cost is reduced by reducing the number of parts.

  According to invention of Claim 4, in addition to the effect of the invention of the cited claim, there exists the following effect. That is, since the number of steps for assembling the additional pressing mechanism with respect to the pressing member is reduced, the assembling property of the additional pressing mechanism with respect to the pressing member having the structure in which the pad is assembled is improved.

  According to the invention described in claim 5, in addition to the effect of the invention described in the cited claim, the following effect is produced. That is, while the frictional resistance of the rack shaft can be increased by the additional biasing force, the increase in the frictional resistance is suppressed, so that the deterioration of the steering feeling is suppressed, and the disturbance described later The movement of the rack shaft is suppressed, and the steerability is improved. In addition, the balance between steering feeling and steerability can be adjusted by the additional pressing mechanism, so various steering feelings can be set to meet the needs of the vehicle type and driver while improving steerability. can do.

Embodiments of the present invention will be described below with reference to FIGS.
1 and 2 are diagrams for explaining a first embodiment of the present invention.
Referring first to FIG. 1, a vehicle rack and pinion type steering device (hereinafter referred to as “steering device”) to which the present invention is applied is a gear box 2 into which a steering force applied to a steering wheel 1 by a driver is input. And a transmission mechanism (not shown) coupled to the gear box 2 for transmitting the steering force to the steered wheels.

  The gear box 2 includes a housing 3 that is attached to the vehicle body, a rack and pinion mechanism that is housed in the housing 3 and transmits a steering force to the transmission mechanism, and a pressing mechanism 10 that is assembled to the housing 3.

  The rack and pinion mechanism has a pinion shaft 5 to which a steering force from the handle 1 is transmitted and is rotatably supported by the housing 3 via a bearing 4, and a shaft to the housing 3 via a bearing (not shown). The rack shaft 6 is supported so as to be capable of reciprocating in the direction. The pinion shaft 5 is provided with a pinion 7 at a part thereof, and the rack shaft 6 is provided with a rack 8 that engages with the pinion 7 at a part thereof.

In the steering device, when the pinion shaft 5 is rotated by the steering force applied by the driver to the steering wheel 1 to steer, the rotating pinion 7 moves the rack shaft 6 in the axial direction (the left-right direction of the vehicle) through the meshing rack 8. ), The steering force is transmitted to the steered wheels via the rack shaft 6.
In the specification, the axial direction and the radial direction mean a direction in which the central axis L1 of the rack shaft 6 extends and a radial direction centered on the central axis L1, respectively.

  Referring also to FIG. 2, the pressing mechanism 10 that presses the rack 8 toward the pinion 7 contacts the back surface 8 a of the rack 8 on the rack shaft 6, and the rack shaft 6 is biased by the biasing force of the first spring 12 described later. The rack guide 11 as a pressing member that presses 8, the first spring 12 as a first biasing member that generates a resilient force acting on the rack guide 11, and the biasing force of the first spring 12 are adjusted In addition to the rack guide 11, an additional pressing mechanism 20 that presses the rack shaft 6 is provided.

  The rack guide 11 is slidably mounted and held in a cylindrical mounting portion 9 provided integrally with the housing 3, and is a support surface that is a contact surface formed in a concave shape along the back surface 8 a of the rack 8. At 14, the rack 8 is pressed and the rack 8 is supported so as to be slidable in the axial direction. The rack guide 11 is a cylindrical main body 15 that is slidably fitted in the holding hole 9 a of the mounting portion 9, and a portion of the main body 15 that is attached to a portion near the rack 8 to contact the rack shaft 6 in the rack guide 11. And a pad 16 made of a member made of synthetic resin, for example, a member having a low friction coefficient.

  The pad 16 having the support surface 14 is fixed to the joint surface 15a of the main body 15 on the back surface, and protrudes radially outward so as to be inserted into the mounting hole 17a of the mounting portion 17 provided in the main body 15. An attachment portion 18 is provided, and the attachment portion 17 is held by the main body 15 by the elastic force of the attachment portion 18. Both mounting portions 17 and 18 are arranged in the center portion of the rack guide 11 in the rack guide 11 at a position intersecting the central axis L <b> 2 of the main body 15. The central axis L2 is orthogonal to the central axis L1.

The first spring 12 made of a compression coil spring is disposed between the rack guide 11 and the plug 13 and is held by the rack guide 11 at one end and held by the plug 13 at the other end.
The plug 13 having the male screw portion 13b is screwed into the female screw portion 9b formed on the peripheral wall surface of the holding hole 9a, and the urging force of the first spring 12 can be adjusted according to the screwing amount.

  The additional pressing mechanism 20 assembled to the rack guide 11 includes a ball 21 as a rolling element that is in rolling contact with the back surface 8 a of the rack 8, and a ball that presses the rack 8 of the rack shaft 6 in addition to the urging force of the first spring 12. The second spring 22 as an additional urging member that generates a resilient force as an additional urging force acting on the member 21 and a case 23 that accommodates the ball 21 and holds it in a rollable manner.

The ball 21 that presses the rack 8 with an additional biasing force is formed of various materials such as steel or synthetic resin.
The second spring 22 is formed from a case 23 by being integrally formed with a case 23 formed of a metal material, for example, tool steel. Here, the second spring 22 is a spring formed in a disc spring shape using a part of the case 23.

  In the additional pressing mechanism 20, by changing the material having a different friction coefficient as the forming material of the ball 21, and by changing the forming material of the second spring 22 and the spring characteristic as a characteristic defining the biasing force, It is possible to adjust the balance between the rudder feeling and the steerability described later.

The case 23 is provided with an opening 24 that allows the ball 21 to be inserted into the case 23 while preventing the ball 21 from coming out of the case 23. When the ball 21 is inserted into the case 23, the opening 24 is expanded by elastically deforming the case 23 to allow the ball 21 to be inserted. After the ball 21 is accommodated in the case 23, the case 24 When 23 returns to its original shape, it returns to a size that prevents the ball 21 from coming out of the case 23. Then, the ball 21 is urged by a second spring 22 disposed on the opposite side of the rack shaft 6 across the ball 21 in the sliding direction in the case 23, and the opening 24 disposed on the rack shaft 6 side. Through the back surface 8a. The side wall 23b of the case 23 surrounding the ball 21 is formed at intervals in the circumferential direction, or is formed continuously over the entire circumference.
In this way, the additional pressing mechanism 20 including the ball 21, the second spring 22, and the case 23 is configured in advance as one unit component A before being assembled to the rack guide 11.

  The rack guide 11 is provided with a holding portion B that houses and holds the additional pressing mechanism 20 that is the unit component A. The unit component A is attached to the holding portion B before the rack guide 11 is assembled to the housing 3. Assembled. Specifically, the unit component A is provided on the mounting portion 18 so as to be held by the mounting portion 18 that is provided on the pad 16 and constitutes the holding portion B before the pad 16 is assembled to the main body 15. It is accommodated and held in the accommodation chamber 19 formed by the recessed portion. In a state where the unit component A is accommodated in the accommodation chamber 19, the second spring 22 abuts on the bottom wall 18 a of the attachment portion 18, and the side wall 23 b of the case 23 abuts on the peripheral wall 18 b of the attachment portion 18.

  The pad 16 is assembled integrally to the rack guide 11 by being assembled to the main body 15 in a state where the additional pressing mechanism 20 that has become the unit component A is incorporated in the pad 16. Then, the rack guide 11 in which the unit component A is built is fitted into the holding hole 9 a and assembled to the housing 3.

  In a state where the unit component A is built in the pad 16, the case 23 is firmly fixed to the mounting portion 17 by the elastic force of the peripheral wall 18b. The rack guide 11 is provided with a support member 31 that supports the bottom wall 18 a that receives the reaction force of the second spring 22.

  After the rack guide 11 is fitted to the mounting portion 9, the plug 13 is screwed to the mounting portion 9, and the lock nut 32 (see FIG. 1) is further screwed to the mounting portion 9. Assembled into. In this state, the rack guide 11 biased by the first spring 12 contacts the back surface 8a at the pad 16 and presses the back surface 8a, and at the same time, the ball 21 biased by the second spring 22 contacts the back surface 8a. Thus, the rack shaft 6 is always pressed by the rack guide 11 and the balls 21 that are always in contact with the rack shaft 6.

  Therefore, the movement of the rack shaft 6 due to an external force such as a road surface reaction force (ie, a force other than a steering force, hereinafter referred to as “disturbance”) acts on the rack shaft 6 via the rack guide 11 when the vehicle travels. In addition to the urging force of the first spring 12, the driver maintains the handle 1 in a predetermined position by being suppressed by an increase in the additional urging force acting on the rack shaft 6 via the ball 21 of the additional pressing mechanism 20. That is, the steerability is improved.

Next, operations and effects of the embodiment configured as described above will be described.
The pressing mechanism 10 of the steering apparatus includes a rack guide 11 biased by a first spring 12 and an additional pressing mechanism 20, and a ball 21 that is in rolling contact with the rack 8 of the rack shaft 6 and the ball 21 are biased. The additional pressing mechanism 20 composed of the second spring 22 is integrally assembled with the rack guide 11 so that the rack guide 11 having the additional pressing mechanism 20 built therein is assembled to the housing 3 in advance. Since the mechanism 20 is incorporated into the pressing mechanism 10, the assembly of the pressing mechanism 10 with respect to the housing 3 is compared with the case where the ball 21 and the second spring 22 are assembled to the rack guide 11 after the rack guide 11 is assembled to the housing 3. The man-hours are reduced and labor is reduced. As a result, the assembling property of the pressing mechanism 10 including the additional pressing mechanism 20 in the steering device is improved.

  Since the additional pressing mechanism 20 is configured as one unit part A and assembled to the rack guide 11, the additional pressing mechanism 20 is assembled to the rack guide 11 as one part, so that the ball 21 and the second spring 22 are provided. Compared with the case where the rack guide 11 is separately assembled, the number of steps for assembling the additional pressing mechanism 20 to the rack guide 11 is reduced. As a result, the assembling property of the additional pressing mechanism 20 to the rack guide 11 is improved, and as a result, the assembling property of the pressing mechanism 10 in the steering device is improved.

  The second spring 22 is constituted by a case 23 that holds the ball 21 in a rollable manner, whereby the structure of the additional pressing mechanism 20 is simplified and the number of parts is reduced. And the cost is reduced by reducing the number of parts.

  The rack guide 11 includes a main body 15 and a pad 16 that forms a contact portion with the rack shaft 6 and is assembled to the main body 15, and the additional pressing mechanism 20 that is a unit part A is assembled to the pad 16. Thus, in the rack guide 11 having the structure in which the pad 16 is assembled, the additional pressing mechanism 20 is incorporated into the rack guide 11 by assembling the pad 16 in which the additional pressing mechanism 20 is built in the main body 15 in advance. Compared with the case where the second spring 22 is assembled after being assembled to the main body 15, the number of assembling steps of the additional pressing mechanism 20 to the rack guide 11 is reduced. As a result, the number of steps for assembling the additional pressing mechanism 20 with respect to the rack guide 11 is reduced, so that the assembling property of the additional pressing mechanism 20 with respect to the rack guide 11 having the structure in which the pad 16 is assembled is improved.

  In a state where the pressing mechanism 10 is assembled to the housing 3, the rack guide 11 and the ball 21 are always in contact with the rack shaft 6 and constantly press the rack shaft 6, whereby the first spring 12 acting on the rack guide 11 is attached. In addition to the force, the frictional resistance of the rack shaft 6 can be increased by the additional biasing force of the added second spring 22, while the increase in the frictional resistance due to the additional biasing force is based on rolling friction. This is suppressed compared to the case of sliding friction. As a result, the deterioration of the steering feeling is suppressed, and the movement of the rack shaft 6 due to disturbance is suppressed, so that the steerability is improved. Also, by changing the forming material of the ball 21 or the forming material of the second spring 22 and the spring characteristics, it is possible to adjust the amount of increase in the frictional resistance by the additional pressing mechanism 20, so that the turning feeling and steering Since the balance with the vehicle can be adjusted, it is possible to set various steering feelings corresponding to the vehicle type and the driver's needs while improving the steering stability.

  When the additional pressing mechanism 20 is assembled using the mounting portions 17 and 18 of the main body 15 and the pad 16, the conventional rack guide 11 provided with the mounting portions 17 and 18 is left as it is or the rack guide 11 Since the additional pressing mechanism 20 can be additionally provided with only a small change, it contributes to the cost reduction of the steering device.

  Next, a second embodiment of the present invention will be described with reference to FIG. The second embodiment is different from the first embodiment in the additional pressing mechanism and the holding portion B, and the rest has basically the same configuration. Therefore, description of the same part is omitted or simplified, and different points will be mainly described. In addition, about the member same as the member of 1st Embodiment, or the corresponding member, the same code | symbol was used as needed.

  The additional pressing mechanism 40 includes a ball 21 and a second spring 42. The second spring 42 is configured by a disc spring that is inserted into the mounting hole 17 a of the mounting portion 17 and is held by the mounting portion 17 by a support member 33 that is fixed to the rack guide 11.

The additional pressing mechanism 40 is assembled to the holding portion B of the rack guide 11 before the rack guide 11 is assembled to the mounting portion 9. Specifically, after the second spring 42 is held on the mounting portion 17 of the main body 15, the ball 21 is inserted into the mounting hole 17a, and then the pad 16 is firmly fixed to the joint surface 15a and in the sliding direction. A cylindrical mounting portion 41 having openings 41a and 41b formed at both ends is inserted into the mounting hole 17a so that the ball 21 is inserted into the mounting portion 41 from the opening 41b opposite to the rack shaft 6. . In the vicinity of the opening 41a of the mounting portion 41 near the rack shaft 6, a stopper 41c that prevents the ball 21 from coming out of the mounting portion 41 is provided so as to protrude into the opening 41a. The balls 21 accommodated in the mounting portions 17 and 41 so as to be able to roll are urged by a second spring 42 disposed on the opposite side of the rack shaft 6 with the balls 21 sandwiched in the sliding direction, thereby opening 41a. Through the back surface 8a.
Therefore, the holding part B provided in the rack guide 11 is constituted by an attaching part 17 as a main body side holding part provided in the main body 15 and an attaching part 41 as a pad side holding part provided in the pad 16.

  In this way, the additional pressing mechanism 40 including the ball 21 and the second spring 42 is assembled integrally with the rack guide 11. The rack guide 11 in which the additional pressing mechanism 40 is built is fitted into the holding hole 9a (see FIG. 2) and assembled to the housing 3 (see FIG. 2).

  According to the second embodiment, operations and effects similar to those of the first embodiment are achieved except that the additional pressing mechanism 40 is not configured as one unit component.

Hereinafter, an embodiment in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration.
The rolling element may be a roller. A plurality of additional pressing mechanisms may be assembled to the rack guide 11. The second spring may be a coil spring.
When the disturbance acting on the rack shaft is small, the rack shaft may be pressed only by the additional pressing mechanism, and when the external force is large, the additional pressing mechanism and the rack guide may press the rack shaft.

It is principal part sectional drawing of the rack and pinion type steering device which is 1st Embodiment of this invention. It is a principal part enlarged view of FIG. It is principal part sectional drawing of the rack and pinion type steering device which is 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Handle, 2 ... Gear box, 3 ... Housing, 4 ... Pinion shaft, 5 ... Bearing, 6 ... Rack shaft, 7 ... Pinion, 8 ... Rack, 9 ... Mounting part, 10 ... Pressing mechanism, 11 ... Rack guide, 12 ... Spring, 13 ... Plug, 14 ... Support surface, 15 ... Main body, 16 ... Pad, 17, 18,41 ... Mounting part, 19 ... Accommodating chamber, 20,40 ... Additional pressure mechanism, 21 ... Ball, 22,42 ... Spring, 23 ... Case, 24 ... Opening, 31,33 ... Support member, 32 ... Lock nut,
L1, L2 ... central axis, A ... unit parts, B ... holding part.

Claims (5)

A rack-and-pinion steering device for a vehicle that transmits a steering force to a steered wheel via a rack shaft provided with a rack that meshes with a pinion that is rotated by a steering force, and presses the rack toward the pinion In the rack and pinion type steering apparatus, wherein the mechanism includes a pressing member that is assembled to the housing and presses the rack shaft by an urging force.
The pressing mechanism includes an additional pressing mechanism including a rolling element that is in rolling contact with the rack shaft and an additional biasing member that generates an additional biasing force that acts on the rolling body that presses the rack shaft. A rack-and-pinion steering device , wherein a pressing mechanism is integrally assembled with the pressing member, and the rolling elements are provided on the pressing member so as not to fall off . A rack-and-pinion steering device for a vehicle that transmits a steering force to a steering wheel via a rack shaft provided with a rack that meshes with a pinion that rotates by a steering force, and presses the rack toward the pinion. In the rack and pinion type steering apparatus, the pressing mechanism includes a pressing member that is assembled to the housing and presses the rack shaft with an urging force.
The pressing mechanism includes an additional pressing mechanism including a rolling element that is in rolling contact with the rack shaft and an additional biasing member that generates an additional biasing force that acts on the rolling body that presses the rack shaft. A rack and pinion type steering device , wherein the pressing mechanism is configured as one unit component and assembled to the pressing member, and the rolling elements are provided on the pressing member so as not to fall off .   The rack-and-pinion steering device according to claim 1 or 2, wherein the additional biasing member is configured by a case that holds the rolling element in a rollable manner.   The pressing member includes a main body and a pad that constitutes a contact portion of the pressing member with the rack shaft and is assembled to the main body, and the additional pressing mechanism is assembled to the pad. The rack and pinion type steering device according to claim 2.   3. The rack and according to claim 1, wherein the pressing member and the rolling element are always in contact with the rack shaft and constantly press the rack shaft in a state where the pressing mechanism is assembled to the housing. Pinion type steering device.

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