JP4997564B2 - Rack shaft support device - Google Patents

Description

  The present invention relates to a rack shaft support device applied to a rack and pinion type steering device.

Some rack and pinion type steering devices include a rack shaft support device that supports a rack shaft, for example. The rack shaft support device uses a coil spring that biases the rack shaft toward the pinion shaft via a support member that supports the rack shaft. In addition, it is necessary to provide a ring made of a synthetic resin for suppressing vibration transmission from the support member separately from the coil spring, and to arrange the coil spring and the ring independently from each other (for example, Patent Documents). 1).
JP 2002-37089 A

However, since the rack shaft support device described in Patent Document 1 uses a plurality of members that are provided separately, the number of assembling steps increases, resulting in high costs. Moreover, there is a problem that the urging force for urging the support member is not stable.
The present invention has been made based on such a background, and an object thereof is to provide a rack shaft support device with good assemblability.

  Another object of the present invention is to provide a rack shaft support device capable of obtaining a stable urging force.

In order to achieve the above object, the present invention is accommodated in a holding hole (11) formed in the housing (7) so as to be slidable in the depth direction (X1) of the holding hole and sliding the rack shaft (4). A rack shaft support member (12) movably supported, a sealing member (13) fixed to the inlet of the holding hole, and a rack shaft support interposed between the sealing member and the rack shaft support member A biasing member (40 , 43, 44) for biasing the member toward the rack shaft side and an embedded member (22) are provided, and this biasing member opens at the center of the end surface (15) of the rack shaft support member. A coil spring (24) embedded in the embedded member and extending radially outward from an end of the coil spring, and an end surface of the rack shaft support member and the coil spring (24). A synthetic resin sandwiched between opposing surfaces (26) of the opposing sealing member or A resilient plate including a beam and a (23, 32), the embedded member and the elastic plate is integrally formed of a single material, the rack upper Symbol coil spring and the elastic plate is integrally coupled to shaft Support device (9).

According to the present invention, since the coil spring and the elastic plate, which are urging members, are integrally connected, it is only necessary to incorporate the integrated urging member, and the assemblability is good. Further, since the position of the coil spring is stabilized by connecting them integrally, the urging force of the urging member can be stabilized. Furthermore, since the embedded member and the elastic plate are integrally formed of a single material , the urging force of the urging member can be stabilized. In addition, the urging force of the urging member can be further stabilized by integrally forming the embedded member and the elastic plate with a single material.

In the present invention, the elastic plate may include an annular plate (23). In this case, since the rack shaft support member abuts on the annular plate over the circumferential direction, it is possible to suppress the rack shaft support member from rattling in the holding hole.
In the present invention, the elastic plate and the embedded member may have an elastic coefficient lower than that of the coil spring. In this case, the rack shaft support member is mainly biased by a coil spring. Thereby, it is possible to stably bias the rack shaft support member while suppressing the influence of deterioration of the elastic plate and the embedded member. Further, the embedded member can expand and contract together with the coil spring.

  In the above description, the alphanumeric characters in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

Embodiments of the present invention will be specifically described below with reference to the drawings.
FIG. 1 is a cross-sectional view of a rack and pinion type steering device 1 to which a rack shaft support device 9 according to an embodiment of the present invention is applied. 2 is an enlarged cross-sectional view showing a part of the rack shaft support device 9 provided in the steering device 1. FIG. 3 is a plan view of the urging member 40 of the rack shaft support device 9. As shown in FIG. .

  Referring to FIG. 1, a steering device 1 includes a pinion shaft 3 connected to a steering member 2 such as a steering wheel, and a rack shaft 4 extending in a direction orthogonal to the axial direction of the pinion shaft 3. The pinion shaft 3 is rotatably supported by a housing 7 via a plurality of bearings 6, and a pinion 5 is formed at the tip thereof. The rack shaft 4 is supported by the housing 7 so as to be movable in the axial direction (direction perpendicular to the paper surface in FIG. 1) via a plurality of guide members (not shown), and a rack 8 is formed in a part of the axial direction. Has been. Although not shown, steering wheels are coupled to both ends of the rack shaft 4 via tie rods and knuckle arms, respectively. The rack 8 and the pinion 5 are meshed with each other in the housing 7.

Further, on the back side of the rack 8 in the rack shaft 4, a rack shaft support device 9 for removing backlash at the meshing portion of the rack 8 and the pinion 5 is provided. The rack shaft support device 9 elastically presses the rack shaft 4 against the pinion shaft 3 to remove the backlash.
The rack shaft support device 9 is held in a holding hole 11 formed in a protruding portion 10 where a part of the housing 7 extends. The holding hole 11 is opened at the tip of the overhanging portion 10, and the depth direction X <b> 1 is a direction orthogonal to the axial directions of the pinion shaft 3 and the rack shaft 4. The rack shaft support device 9 includes a rack shaft support member 12 accommodated in the holding hole 11 so as to be slidable in the depth direction X1, and a sealing member fixed near the opening of the holding hole 11 and sealing the opening. And a biasing member 40 that is interposed between the rack shaft support member 12 and the plug 13 and biases the rack shaft support member 12 toward the rack shaft 4.

  The rack shaft support member 12 has an end surface 14 that faces the back surface of the rack shaft 4, and a concave surface 16 that conforms to the shape of the back surface of the rack shaft 4 is formed on the end surface 14. The rack shaft support member 12 supports the back surface of the rack shaft 4 through a pad 17 attached to the concave surface 16 by adhesion, for example, so that the rack shaft 4 and the pad 17 are in sliding contact with each other. It has become.

  A plurality of annular grooves 18 extending in the circumferential direction are formed on the outer peripheral surface of the rack shaft support member 12. An annular elastic member 19 such as an O-ring is held in each of the plurality of annular grooves 18, and the elastic member 19 is formed between the annular groove 18 and the inner peripheral surface of the protruding portion 10 that forms the holding hole 11. It is elastically compressed between. As a result, the rack shaft support member 12 is elastically supported by the housing 7 via the elastic member 19.

  The plug 13 has a cylindrical shape, and a male screw is formed on the outer periphery thereof. Further, a tool engagement hole 20 having a polygonal cross section, for example, is formed on one end face of the plug 13 in the axial direction. By engaging the tool (not shown) in the tool engagement hole 20 and rotating the plug 13, the plug 13 is screwed into the female screw formed on the inner peripheral surface of the holding hole 11 to seal the opening of the holding hole 11. Can be stopped. Further, the relative position of the plug 13 with respect to the holding hole 11 can be displaced by changing the screwing amount of the plug 13 into the holding hole 11. Furthermore, the lock nut 21 fitted to the plug 13 is fastened to the peripheral edge of the opening of the holding hole 11, whereby the plug 13 is fixed to the housing 7. Thereby, the tip of the plug 13 is positioned and fixed at a predetermined position in the depth direction X1 of the holding hole 11.

As shown in FIGS. 1 and 3, the biasing member 40 includes a columnar embedded member 22 and an annular plate 23 as an elastic plate integrally formed of a single material. Examples of the single material forming the embedded member 22 and the annular plate 23 include synthetic resin and synthetic rubber.
A coil spring 24 having a higher elastic coefficient than that of the embedded member 22 and the annular plate 23 is embedded in the embedded member 22. The buried member 22 and the coil spring 24 are arranged such that their center axes coincide with each other. Further, the embedded member 22 and the annular plate 23 are arranged coaxially. The annular plate 23 has a larger diameter and is thinner than the embedded member 22. The annular plate 23 is an annular flange extending from the end of the embedded member 22 toward the radially outer side of the embedded member 22.

  The embedded member 22 is accommodated in an accommodation hole 25 formed in the other end surface 15 of the rack shaft support member 12. The accommodation hole 25 is opened at the center of the other end surface 15 of the rack shaft support member 12, and the embedded member 22 is fitted into the accommodation hole 25 through this opening. The inner diameter of the accommodation hole 25 is equal to or slightly larger than the outer diameter of the embedded member 22, and the embedded member 22 is held in the accommodation hole 25 without rattling.

On the other hand, the annular plate 23 is in contact with the other end face 15 of the rack shaft support member 12. Specifically, the outer diameter of the annular plate 23 is slightly smaller than the outer diameter of the rack shaft support member 12, as shown in FIG. Thus, the annular plate 23 is in contact with most of the other end surface 15 of the rack shaft support member 12.
The embedding member 22 and the coil spring 24 of the biasing member 40 are sandwiched and elastically deformed by the bottom surface of the accommodation hole 25 and the facing surface 26 of the plug 13 facing the receiving hole 25. The annular plate 23 is sandwiched between the other end surface 15 of the rack shaft support member 12 and the facing surface 26 of the plug 13 and is elastically deformed. Elastic reaction force due to elastic deformation of the embedded member 22, the annular plate 23 and the coil spring 24 is applied to the rack shaft support member 12. Therefore, the rack shaft 4 is elastically pressed against the pinion shaft 3, and the backlash between the rack 8 and the pinion 5 is removed.

  According to this embodiment, the assembling property of the rack shaft support device 9 can be improved by integrating the biasing member 40 including a plurality of members. Further, the urging force of the urging member 40 can be stabilized by embedding the coil spring 24 in the burying member 22 and stabilizing the position of the coil spring 24. Furthermore, by making the elastic coefficient of the embedded member 22 and the annular plate 23 lower than that of the coil spring 24, the biasing member 40 can be stably racked without being affected by the deterioration of the embedded member 22 and the annular plate 23. The shaft support member 12 can be biased. Furthermore, rattling of the rack shaft support member 12 in the holding hole 11 can be effectively suppressed by making the outer diameter of the annular plate 23 substantially equal to the outer diameter of the rack shaft support member 12.

FIG. 4 is a longitudinal sectional view schematically showing the biasing member 41 according to the reference embodiment. In FIG. 4, the same components as those shown in FIGS. 1 and 3 described above are denoted by the same reference numerals as those in FIGS. 1 and 3, and description thereof is omitted.
The present reference embodiment differs mainly with the embodiment of FIG. 1 in place of the embedded member 22 in FIG. 1, fitted the shaped tube which is integrally formed of a single material and the annular plate 23 members 28 Is that it is provided. The cylindrical outer fitting member 28 is closed at one end in the axial direction and opened at the other end. The coil spring 24 is fixed, for example, by being press-fitted into a bottomed hole in the cylindrical outer fitting member 28.

According to this reference embodiment, the coil spring 24 can be easily fixed to the outer fitting member 28 by press-fitting the coil spring 24 into the cylindrical outer fitting member 28. Further, since the urging member 41 is integrated with the coil spring 24, the outer fitting member 28, and the annular plate 23, the assembling property is good as in the above-described embodiment.
The cylindrical outer fitting member 28 may be formed with a slit extending in the axial direction.

FIG. 5 is a longitudinal sectional view schematically showing an urging member 42 according to another reference embodiment. 5, the same components as those shown in FIGS. 1 and 3 described above are denoted by the same reference numerals as those in FIGS. 1 and 3, and the description thereof is omitted.
The present reference embodiment differs mainly with the embodiment of Figure 1, instead of the embedded member 22 in FIG. 1, is provided an inner fitting member 29 solid cylindrical shape in which are disposed in an annular plate 23 coaxially with There is in being. The inner fitting member 29 is formed integrally with the annular plate 23 with a single material. The inner fitting member 29 has a length equal to or less than the axial length of the coil spring 24, and the coil spring 24 and the inner fitting member 29 are brought into contact with each other by press-fitting the inner fitting portion 30 into the inner periphery of the coil spring 24. It is fixed integrally.

According to this reference embodiment, the coil spring 24 can be easily fixed to the inner fitting member 29 by press-fitting the inner fitting portion 30 of the inner fitting member 29 into the inner periphery of the coil spring 24. Moreover, since the internal fitting member 29 is a simple shape, workability is also good.
The internal fitting member 29 may be cylindrical. In this case, the inner fitting member 29 may be formed with a slit extending in the axial direction.

FIG. 6 is a plan view schematically showing an urging member 43 according to another embodiment of the present invention . In FIG. 6, the same components as those shown in FIGS. 1 and 3 described above are denoted by the same reference numerals as those in FIGS. 1 and 3, and description thereof is omitted.
The main difference between the present embodiment and the embodiment shown in FIG. 4 is that the hollow holes 31 are formed at a plurality of locations in the circumferential direction of the annular plate 23. Further, these lightening holes 31 are arranged at equal intervals in the circumferential direction of the annular plate 23.

  According to this embodiment, the material of the annular plate 23 can be reduced and the cost of the biasing member 40 can be suppressed. Further, since the hollow holes 31 are arranged at equal intervals in the circumferential direction of the annular plate 23, the biasing force can be applied from the annular plate 23 to the rack shaft support member 12 without deviation in the circumferential direction. it can. Thereby, rattling of the rack shaft support member 12 in the holding hole 11 can be suppressed.

FIG. 7 is a plan view schematically showing an urging member 44 according to still another embodiment of the present invention. In FIG. 7, the same components as those shown in FIGS. 1 and 3 described above are denoted by the same reference numerals as those in FIGS. 1 and 3, and description thereof is omitted.
This embodiment is mainly different from the embodiment shown in FIG. 4 in that a plurality of elastic plates 32 extending radially outward from one axial end of the embedded member 22 instead of the annular plate 23 in FIG. Is that it is provided. The plurality of elastic plates 32 are integrally formed of a single material with the embedded member 22. Further, the plurality of elastic plates 32 are arranged at equal intervals in the circumferential direction of the embedded member 22.

According to this embodiment, material can be reduced rather than the annular plate 23 in FIG. In addition, by arranging the elastic plates 32 at equal intervals in the circumferential direction of the embedded member 22, the rack shaft support member 12 can be uniformly biased in the circumferential direction.
The present invention is not limited to the contents of the above embodiments, and various modifications can be made within the scope of the claims.

1 is a cross-sectional view of a rack and pinion type steering device to which a rack shaft support device according to an embodiment of the present invention is applied. It is an expanded sectional view which shows a part of rack shaft support apparatus with which the said steering apparatus was equipped. It is a top view of the urging member of the rack shaft support device. It is the longitudinal cross-sectional view which showed typically the biasing member which concerns on a reference form. It is the longitudinal cross-sectional view which showed typically the biasing member which concerns on another reference form. It is the top view which showed typically the biasing member which concerns on other embodiment of this invention . It is the top view which showed typically the biasing member which concerns on other embodiment of this invention.

Explanation of symbols

4 ... rack shaft, 7 ... housing, 9 ... rack shaft support device, 11 ... holding hole, 12 ... rack shaft support member, 13 ... plug (sealing member), 15 ... the other end face (the end face of the rack shaft support member), 22 ... the embedded member, 23 ... the annular plate (elastic plate), 24 ... the coil spring, 25 ... the accommodation hole (the spring accommodation hole) ), 26 ... opposing surface, 32 ... elastic plate, 40 to 44 ... biasing member, X1 ... depth direction

Claims (3)

A rack shaft support member that is slidably accommodated in a depth direction of the holding hole in a holding hole formed in the housing and slidably supports the rack shaft;
A sealing member fixed to the inlet of the holding hole;
A biasing member interposed between the sealing member and the rack shaft support member and biasing the rack shaft support member toward the rack shaft ;
With a buried member ,
The biasing member is accommodated in a spring accommodating hole that opens at the center of the end surface of the rack shaft support member, and the coil spring embedded in the embedded member and radially outward from the end of the coil spring. And an elastic plate including a synthetic resin or rubber sandwiched between the end surface of the rack shaft support member and the facing surface of the sealing member facing the rack shaft support member,
A rack shaft support device in which the embedded member and the elastic plate are integrally formed of a single material, and the coil spring and the elastic plate are integrally connected. 2. The rack shaft support device according to claim 1, wherein the elastic plate includes an annular plate. 3. The rack shaft support device according to claim 1, wherein the elastic plate and the embedded member have an elastic coefficient lower than that of the coil spring.

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