JP2001247047A - Installing structure of steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an elastic member from protruding from a prescribed installing position in an installing structure for installing a steering device in a car body. SOLUTION: This installing structure 10 of the steering device 1 elastically supports a cylinder 4 for constituting a power cylinder 3 fitted with the elastic member 15 in a state of fastning an installing bracket 12 to a base bracket 13. The elastic member 15 is compressed by an inner peripheral surface of circular arc-shaped recessed parts 22, 26 of both brackets 13, 12. An inner diameter of an end part is formed relatively larger than an intermediate part of the recessed parts 22, 26. Compressibility is relatively reduced more than the intermediate part of the elastic member 15 in response to the end part of the recessed parts 22, 26, while preventing protrusion of the elastic member 15 at fastening time, sufficient sealing performance is secured in the intermediate part. The elastic member 15 seals a cisclip installing inserting hole 32 formed in the cylinder 4. Thus, a rubber boot can be easily installed. A structure can be simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile steering system. In particular, the present invention relates to a mounting structure for mounting a steering device to a vehicle body.

[0002]

2. Description of the Related Art For example, a steering device has a rack shaft for steering wheels, and a housing for accommodating the rack shaft so as to reciprocate in the axial direction. This housing is formed in a cylindrical shape extending in the axial direction. A part of the outer peripheral surface in the axial direction of the housing is fixed to the vehicle body by the following mounting structure. That is, Ω
A base bracket having a character shape and attached to the vehicle body and a mounting bracket having an inverted Ω shape and fastened to the base bracket are used. A holding space for a housing covered with a cylindrical elastic member is formed between the arc-shaped concave portions of both brackets, and the housing is elastically supported by both brackets via the elastic member.

[0003] Usually, the above-mentioned elastic member not only plays a role of elastically supporting the housing but also plays a role of sealing the housing so that there is no entry of water or dust. This is because an insertion hole that penetrates the inside and outside of the housing is provided in a portion of the peripheral surface of the housing that is attached by the attachment structure, and it is necessary to prevent water from entering through the insertion hole. The reason why such an insertion hole is necessary is as follows. That is, an end member that seals the inside of the housing (for example, a rack stopper)
A pair of circumferential grooves facing each other are formed on the inner peripheral surface of the housing and the outer peripheral surface of the end member, and a circlip groove is formed by the pair of peripheral grooves. This is because a circlip made of a steel wire is fitted into the circlip groove in the housing through the above-described insertion hole because it is necessary to fix the end member in the housing in both directions.

[0004]

By the way, in the above-mentioned mounting structure, the elastic member has a diameter between the brackets so as to obtain a sufficient holding force for securing the sealing performance and preventing the rattling of the housing. It is strongly compressed in the direction. Therefore, the elastic member expands in the axial direction while being compressed by the two brackets in the radial direction and contracting. As a result, a part of the elastic member tends to protrude outward from the end of the mounting bracket in the axial direction.

If the elastic member protrudes and enters, for example, the mounting groove of the rubber boot, the rubber boot cannot be mounted at an appropriate position on the housing and is easily detached. Therefore, it is necessary to attach the rubber boot to the housing while pushing out the protruding elastic member so that the rubber boot can be arranged at an appropriate position. As a result, it took time to assemble the rubber boots. In order to prevent the elastic member from protruding, it is conceivable to reduce the compression of the elastic member. However, if the elastic member is not sufficiently compressed, the holding force and the sealing performance are reduced. Therefore, weakening the compression is not preferred.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned technical problems and to provide a mounting structure of a steering device capable of preventing the elastic member from protruding while preventing a decrease in holding force or the like.

[0007]

According to the first aspect of the present invention, there is provided a mounting bracket for pressing a cylinder through an elastic member and holding the cylinder in a state where the cylinder is fastened to a fixed portion. A mounting structure for a steering device, wherein a compression ratio of an elastic member at at least one end in the axial direction of the mounting bracket is smaller than a compression ratio at an intermediate portion in the axial direction when the mounting bracket is fastened. I will provide a.

According to the present invention, since the compression ratio of the elastic member is relatively low at the axial end of the mounting bracket, it is possible to prevent the elastic member from protruding outside from the end of the mounting bracket. . On the other hand, at the intermediate portion in the axial direction of the mounting bracket, the elastic member is sufficiently compressed to obtain a high elastic force, so that a sufficient force for maintaining the housing in a liquid-tight manner can be secured. According to a second aspect of the present invention, in the mounting structure for a steering device according to the first aspect, by expanding an inner diameter of an end of the mounting bracket, the accommodation space of the elastic member corresponds to the end of the mounting bracket. Provided is a mounting structure for a steering device, which is relatively widened.

According to the present invention, the cost for preventing the protrusion can be reduced. This is because if the shape is changed so that the inner diameter of the end of the small mounting bracket is enlarged, the processing cost can be reduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A mounting structure of a steering device according to an embodiment of the present invention will be described below. FIG. 1 is a partial sectional view showing a schematic configuration of a mounting structure of a steering device. FIG. 2 is a partial side sectional view showing a schematic configuration of the mounting structure in FIG. 1, and shows a BB section in FIG. 1. The steering device 1 is of a rack and pinion type, and is configured as a power steering device that can obtain a steering assist force. The steering device 1 includes a rack shaft 2 that reciprocates for steering a wheel (not shown) by the movement of a steering wheel (not shown), and a power cylinder 3 that applies a steering assist force to the rack shaft 2. Have. The end of the rack shaft 2 is connected to wheels via joints and tie rods (not shown).

The power cylinder 3 has a cylindrical cylinder 4 for accommodating the rack shaft 2 so that the rack shaft 2 can be reciprocally moved in the axial direction thereof, and is fitted into the cylinder 4 to regulate the moving range of the rack shaft 2. And a stopper 5 as an end member. The stopper 5 also serves as a bush that supports the rack shaft 2. The cylinder 4 extends in the axial direction of the rack shaft 2 (see arrow S; hereinafter, referred to as the axial direction). In the cylinder 4, between a pair of end members,
A pair of oil chambers arranged in the axial direction are defined. A pair of oil chambers includes a piston (not shown) fixed to the rack shaft 2.
Is divided on both sides. Power cylinder 3
Constitutes a hydraulic cylinder, and can apply a steering assist force to the rack shaft 2 via a piston by a hydraulic pressure of hydraulic oil supplied to one oil chamber. Further, a circlip 6 formed of an annular member for locking the stopper 5 at a predetermined position in the cylinder 4 is provided.

The circlip 6 is made of, for example, a steel wire having a circular cross section, and serves to prevent the stopper 5 from moving relative to the cylinder 4 in both directions. A pair of circumferential grooves facing each other are formed on the inner circumferential surface of the cylinder 4 and the outer circumferential surface of the stopper 5, and these pair of circumferential grooves constitute a circlip groove. Is engaged. The outer peripheral surface 31 of the cylinder 4 is formed with an insertion hole 32 that communicates the circlip groove with the outside of the cylinder 4 and extends in the circumferential direction. The circlip 6 can be easily fitted into the circlip groove through the insertion hole 32. Although the insertion hole 32 is open,
Since sealing is performed as will be described later, problems such as flooding do not occur.

The cylinder 4 has an outer peripheral surface 31 formed by a circumferential surface. At one end of the cylinder 4 in the axial direction, a rubber boot 7 (only a part is shown) that covers a joint, a tie rod, and the like is fixed. This rubber boot 7
It is fixed to the outer peripheral surface 31 of the cylinder 4 in a tightened state by a ring 8 wound around the outer peripheral surface. Rubber boots 7
The holding member 11 of the mounting structure 10 of the steering device 1 is arranged adjacent to the steering wheel 1. The mounting structure 10 and the steering device 1 are configured as an integrated unit, and this unit is mounted on the vehicle body.

The mounting structure 10 is formed in an Ω shape and has a body 6
0 (only a part is shown in FIG. 2), and a mounting bracket 12 having an inverted Ω shape and fastened to the base bracket 13. The mounting bracket 12 and the base bracket 13 are fastened by a pair of bolts 14 to form a holding member 11 that holds the cylinder 4. Both brackets 12, 13
Has arc-shaped concave portions 26 and 22. The recesses 26 and 22 of the brackets 12 and 13 are arranged to face each other, and the cylinder 4 having a cylindrical elastic member 15 between them.
Is formed. As a result, the cylinder 4 is connected to both brackets 12, 1 via the elastic member 15.
3 are elastically supported.

The base bracket 13 has an attachment portion 21 including a fitting hole for attachment to the vehicle body 60 and the above-described recess 2.
2 and a pair of bolts 1
4 has a pair of female screws 23 to be screwed. The recess 22 forms substantially half of the holding space 16, and its arc forms a semicircle. The mounting bracket 12 is formed by press-molding a metal plate, and has the above-described concave portion 26 and a pair of insertion holes 27 through which the pair of bolts 14 are inserted. The concave portion 26 forms substantially half of the holding space 16, and its arc forms a semicircle.

The elastic member 15 includes a cylindrical portion 34 formed in a cylindrical shape and extending in the axial direction, and a pair of disk-like members provided at both axial ends of the cylindrical portion 34 and extending radially outward. And a flange 35, and these parts are integrally formed. The cylindrical portion 34 is formed to have substantially the same length as the axial length of the concave portions 22 and 26, and the surfaces of the pair of flanges 35 facing each other correspond to the edge portions at the axial ends of the concave portions 22 and 26. It is along. The inner peripheral surface of the cylindrical portion 34 is fitted to the outer peripheral surface 31 of the cylinder 4, and the outer peripheral surface of the cylindrical portion 34 is
2, 26. The elastic member 15 is made of a rubber material such as natural rubber or synthetic rubber.

The holding space 16 is defined by a concave portion 22 of the base bracket 13 and a concave portion 26 of the mounting bracket 12. The holding space 16 includes the base bracket 13
When the mounting bracket 12 and the mounting bracket 12 are fastened, they extend in the axial direction with a substantially circular cross section. The cylinder 4 in which the elastic member 15 is fitted is disposed in the holding space 16. The accommodation space 17 for accommodating the elastic member 15 shares a part with the holding space 16, and a cylindrical portion 34 of the elastic member 15 is provided between the inner surface of the holding space 16 and the outer peripheral surface 31 of the cylinder 4. A part of the housing space 17 for housing. The mounting bracket 12 is attached to the base bracket 13 with the bolt 1
4, the cylinder 4 is pressed through the elastic member 15 in the holding space 16 and held therein.

In this embodiment, both brackets 12, 1
By enlarging the inner diameter of both ends of the concave portions 26 and 22 in the axial direction, the accommodation space 17 is relatively widened corresponding to the ends of the brackets 12 and 13. As a result, when the mounting bracket 12 is fastened, the compression ratio of the elastic member 15 at both axial ends of the brackets 12 and 13 is smaller than the compression ratio at the axial middle portion. In particular, the compression ratio of the elastic member 15 at both ends in the axial direction of both brackets 12 and 13 is smaller than the compression ratio at the portion adjacent to each end.

Here, the compression ratio is a value of the ratio of (the amount of change in the volume of the elastic member 15 between the natural state and the compressed state) to (the volume of the elastic member 15 in the natural state). The above-mentioned natural state is a state in which the elastic member 15 is fitted on the outer peripheral surface 31 of the cylinder 4, and the two brackets 12 and 13
It is in a state where it is not fitted in. The compressed state means that the mounting bracket 12 is fastened to the base bracket 13,
In the meantime, the elastic member is attached together with the cylinder. Further, the volume is measured per unit length in the axial direction.

The recess 26 is formed by a circumferential surface, and has a relatively small inner diameter at an intermediate portion 29 in the axial direction, and a relatively large inner diameter at both ends 28 in the axial direction. Between the end portion 28 and the intermediate portion 29, the inner diameter is gradually increased toward the end portion 28. The concave portion 22 is formed similarly to the concave portion 26. For example, the inner diameter is relatively small at an intermediate portion in the axial direction, and is relatively large at both end portions in the axial direction. The outer peripheral surface 31 of the cylinder 4 is a portion corresponding to the concave portions 22 and 26 and has a circumferential surface having a constant outer diameter in the axial direction.

The accommodating space 17 has an outer peripheral surface 31 of the cylinder 4.
And the inner peripheral surfaces of the recesses 22 and 26 are formed in an annular shape, and have an outer diameter that varies depending on the position in the axial direction and a constant inner diameter. The accommodation space 17 includes both brackets 12 and 13.
Are relatively wider corresponding to both ends than the middle part. The elastic member 15
The cylindrical portion 34 has a constant thickness (dimension in the radial direction) in the axial direction, and the outer diameter of the cylindrical portion 34 in the natural state described above corresponds to the accommodation space in a state where the brackets 12 and 13 are fastened. 17 is larger than the outer diameter.

The assembly of the mounting structure 10 will be described. First, the elastic member 15 is fitted into a predetermined position in the axial direction of the outer peripheral surface 31 of the cylinder 4. Then, the elastic member 15 is arranged in the recess 22 of the base bracket 13 together with the cylinder 4. The mounting bracket 12 is mounted so as to face the base bracket 13 (see FIG. 3A). The mounting bracket 12 is fastened to the base bracket 13 by bolts 14. When the bolt 14 is tightened, both brackets 12, 1
The axially intermediate portion 3 has a strongly compressed elastic member 15.
Thus, a sufficient holding force can be obtained. In addition, both brackets 1
At the axial end portions 2 and 13, the elastic member 15 is weakly compressed, does not protrude from the end portion, and is locked against the axial extension of the elastic member 15 near the middle portion. (See FIG. 3B).

As described above, according to the present embodiment, the compression ratio of the elastic member 15 is made smaller at the portions corresponding to both ends than at the intermediate portion between the concave portions 22 and 26. As a result, the elastic members 1 are provided at the axial ends of the brackets 12 and 13.
Since the compression ratio of the elastic member 15 is relatively low, it is possible to suppress the elastic member 15 from protruding outward from the ends of the brackets 12 and 13. On the other hand, both brackets 12, 1
At the intermediate portion in the axial direction of 3, the elastic member 15 is sufficiently compressed to obtain a high elastic force, so that a sufficient force for holding the cylinder 4 in a liquid-tight manner can be secured.

It is preferable to increase the inner space of the ends of both brackets 12 and 13 so as to widen the accommodation space 17 in order to reduce the cost for preventing protrusion. The reason is that if the shape is changed so that the inner diameter of the end of the small mounting bracket 12 or the base bracket 13 is enlarged, the processing cost can be reduced. For example, it is only necessary to process a part of a press die for press-forming both brackets 12 and 13.

In particular, in the case where the inner diameter of the end of the mounting bracket 12 or the base bracket 13 is increased and the outer diameter of the cylinder 4 is not reduced, but the circumferential surface has the same diameter in the axial direction,
The processing cost can be further reduced as compared with the case where the inner diameter of the end of the cylinder 4 is merely reduced. That is, the small mounting bracket 12 and the base bracket 13
This is because the processing cost for increasing the inner diameter of the end portion is lower than the processing cost for reducing the outer diameter of the cylinder 4 which is a large part. Further, the cylinder 4 can be used as it is in a conventional shape.

In order to reduce the compression ratio at the end,
Since the accommodation space 17 is widened, for example, the elastic member 1
5, the thickness of the cylindrical portion 34 can be made uniform in the axial direction.
The elastic member 15 can be used as it is in the conventional shape. Also, corresponding to between the end portions of the concave portions 22 and 26 and the intermediate portion,
The compression ratio of the elastic member 15 is configured to gradually change in the axial direction. This prevents the elastic member 15 from being unduly deformed.

The inner peripheral surfaces of the recesses 22 and 26 extend in the axial direction at the ends so that the elastic member 15 can be securely locked. In addition, the elastic member 15 functions as a cushion member and also functions as a seal member. That is, dust and water from the outside are removed between the brackets 12 and 13 and the elastic member 15 and the elastic member 15 by the elastic member 15.
And the cylinder 4 are prevented from intruding, and the hydraulic oil from inside the cylinder 4 is prevented from flowing out.

In particular, in the present embodiment, as described above, the insertion hole 32 for mounting the circlip 6 is formed on the outer peripheral surface 31 of the cylinder 4. Correspondingly, the elastic member 15
As shown in FIG. 4, ridges 36 and 37 for sealing the insertion hole 32 are formed on the inner peripheral surface of the hole. The above-mentioned insertion hole 32
Are arranged to open toward the base bracket 13. The ridges 36 and 37 protrude radially inward in a substantially semicircular cross section. The ridge 36 is inserted into the insertion hole 3
2 is formed in an annular shape so as to surround the insertion hole 32 at an axial position corresponding to the base bracket 13 and the cylinder 4.
Are disposed at a portion sandwiched between the two. The ridge 37 is
A pair extends continuously in the circumferential direction. The ridges 37 are arranged on both sides, which are axially closer to the ends than the ridges 36. The ridges 36 and 37 are attached to both brackets 12 and 13.
The elastic member 15 is provided at an axial position where the compressibility of the elastic member 15 is increased corresponding to the middle portion of the elastic member 15. While the elastic member 15 is compressed, the ridges 36 and 37 are
1 and is securely contacted along 1 to seal the periphery of the insertion hole 32. As described above, since the elastic member 15 as the cushioning member of the mounting structure 10 can be integrated with the sealing member, the size and cost of the mounting structure 10 can be reduced as compared with the case where the elastic member 15 is provided separately. it can.

When the brackets 12 and 13 are fastened, the boundary between the elastic member 15 and the recesses 22 and 26 is formed in a crank shape, and the seal length along the boundary is increased. Thereby, the sealing performance at the end can be further improved. Further, the inner peripheral surface of the elastic member 15 can sufficiently contact the outer peripheral surface 31 of the cylinder 4 over the axial length of the cylindrical portion 34 and the pair of flanges 35, so that sufficient holding force and sealing performance can be secured. ,
Particularly, it is preferable for sealing the insertion hole 32.

As described above, it is possible to prevent the elastic member 15 from protruding from the mounting structure 10 while preventing a decrease in the holding force, the sealing performance, and the like. Therefore, since the flange 35 and the end surface of the holding member 11 can be reliably aligned, it is possible to prevent rattling due to an axial force acting during the steering operation. In addition, there is no need to separately provide a member for preventing the protrusion adjacent to the elastic member 15 in the axial direction, and the structure of the steering device 1 can be simplified and downsized. Further, as described later, the labor for attaching the rubber boot 7 can be reduced, and the workability of the assembly can be improved. Moreover, in order to obtain these effects, a simple structure in which the concave portions 22 and 26 of the holding member 11 are expanded at the ends in the axial direction can be realized.

Further, since the elastic member 15 can be positioned by aligning the flange 35 of the elastic member 15 with the end surfaces of the mounting bracket 12 and the base bracket 13, workability in assembling the mounting structure 10 is good. Since both brackets 13 and 12 are provided so that both recesses 22 and 26 are semicircular,
The cylinder 4 and the elastic member 15 can be easily attached. In the above-described embodiment, the compression ratio of the elastic member 15 is reduced at both axial ends of the brackets 12 and 13, but the compression ratio of the elastic member 15 is reduced at at least one end. Just do it. In particular, it is preferable that this one end is an end closer to the rubber boot 7. That is, if the elastic member 15 protrudes, the protruding elastic member 15 may enter the position of the outer peripheral surface 31 of the cylinder 4 to which the rubber boot 7 is attached. If the rubber boot 7 is not attached to the cylinder 4 at an appropriate position, the rubber boot 7 tends to come off easily. To prevent this, the elastic member 15
Is displaced, and the rubber boot 7 is attached to an appropriate position, so that it takes time and effort to attach the rubber boot 7. On the other hand, in the present embodiment, the protrusion can be prevented, so that there is no trouble in attaching the rubber boot 7 and there is no possibility that the rubber boot 7 comes off.

The cylinder 4 held by the mounting structure 10 is a cylindrical member constituting the power cylinder 3, but is not limited to this. For example, the mounting structure 10
It may hold a cylindrical member that accommodates a gear for displacing the rack shaft 2. As described above, the above-described cylinder may be a cylindrical member, and the cross-sectional shape is not limited to a circle. Further, the mounting structure 10 is not limited to the one that constitutes the unit as described above. For example, the above-described base bracket 13 is configured as a fixed portion that is integral with a part of the vehicle body.
A non-unit mounting structure in which the elastic member 15 and the mounting bracket 12 are fastened by the bolts 14 may be used.

In the above embodiment, the housing space 17
Although the inner diameter of the ends of the concave portions 22 and 26 is made larger than that of the intermediate portion in order to increase the width, the present invention is not limited to this. For example,
The outer diameter of the outer peripheral surface 31 of the cylinder 4 corresponding to the ends of both brackets 12 and 13 may be smaller than the outer diameter corresponding to the intermediate part. To reduce the compression ratio, the accommodation space 17 is widened as described above, and the thickness of the elastic member 15 in the natural state is made relatively thin at the portions corresponding to the ends of the recesses 22 and 26. It is also possible.

In addition, various design changes can be made without changing the gist of the present invention.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional front view showing a schematic configuration of a mounting structure of a steering device according to an embodiment of the present invention, and FIG.
3A shows a cross section.

FIG. 2 is a partial cross-sectional side view showing a schematic configuration of the mounting structure of FIG. 1, and shows a cross section taken along line BB of FIG.

3 is an enlarged front cross-sectional view of a main part of a portion C of the mounting structure in FIG. 1, wherein (a) shows a state before bolt fastening and (b) shows a state after bolt fastening.

FIG. 4 is a front sectional view of an elastic member of the mounting structure of FIG. 1;

[Explanation of symbols]

 Reference Signs List 4 Cylinder 10 Mounting structure 12 Mounting bracket 13 Base bracket (fixed part) 15 Elastic member 17 Housing space 28 End of mounting bracket 29 Intermediate part S Axial direction

Claims (2)

[Claims] 1. A mounting bracket for pressing and holding a cylinder via an elastic member in a state where the cylinder is fastened to a fixed portion, and at least one end of the mounting bracket in the axial direction when the mounting bracket is fastened. Wherein the compression ratio of the elastic member is smaller than the compression ratio of the intermediate portion in the axial direction. 2. The mounting structure for a steering device according to claim 1, wherein an inner diameter of an end of the mounting bracket is increased.
A mounting structure for a steering device, wherein an accommodation space for an elastic member is relatively widened corresponding to an end of a mounting bracket.