JP2002037092A - Bush and steering system mounting structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of causing the dispersion of mounting rigidity by the dislocation of a bush for elastic support in mounting structure of a steering system of an automobile to an automobile body. SOLUTION: This bush 9 in the mounting structure 7 is provided with a metal cylinder 12, an elastic member 13 integrated with the outer periphery of the metal cylinder 12, and a positioning means 14 engaged with a housing 3 to circumferentially position the elastic member 13. The positioning means 14 comprises a recessed groove 26 formed on the outer periphery of the elastic member 13. The recessed groove 26 is fitted to a protrusion 33 formed at the housing 3, to accurately position the elastic member 13. Load characteristic different from each other in two orthogonal directions of the elastic member 13 of deformed cross section can thereby be stabilized to reduce the dispersion of mounting rigidity. Accurate positioning is thereby facilitated, and cost is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bush used for mounting a steering device of an automobile on a vehicle body.

[0002]

2. Description of the Related Art The above-mentioned mounting structure includes a housing of a steering device, a bush fitted in a hole of the housing, and a bolt inserted through the bush and screwed into a vehicle body. I have. The bush includes a metal tube and a cylindrical rubber material integrally formed on the outer periphery of the metal tube. The steering device is elastically supported on the vehicle body via the bush. By the way, there is an attachment structure in which the attachment rigidity in a predetermined direction of the vehicle body is relatively increased, and the attachment rigidity in another direction is relatively decreased.

In this case, a bush having a rubber material having an irregular cross section is used and pressed into a hole of the housing. However, it is extremely difficult to accurately position the pressed bush in the circumferential direction of the hole. is there. This is because, in the case of deformed rubber material, the meat tends to move in the circumferential direction during press-fitting, so even if the bushing is accurately positioned with respect to the housing before press-fitting, the bushing in the circumferential direction of This is because the position changes. As a result, the direction of the bush varies from vehicle body to vehicle body, and the variation in mounting rigidity from vehicle to vehicle has increased.

[0004] It is therefore an object of the present invention to solve the above-mentioned technical problems and to provide a mounting structure of a steering device and a bush which can be used for the structure, which can easily reduce a variation in mounting rigidity for each individual. .

[0005]

According to the first aspect of the present invention, there is provided a bush which is inserted into a hole of a steering device for elastically supporting the housing of the steering device on a vehicle body. A cylindrical elastic member integrally formed around the metal cylinder and having different load characteristics according to at least two different radial directions while the outer periphery is constrained by the housing; And a positioning means for positioning the elastic member in the circumferential direction.

According to the present invention, since the direction of the bush can be accurately set, the variation in the mounting rigidity of the steering device can be reduced. Here, as the positioning means, one of a pair of fitting portions composed of a concave portion and a convex portion fitted to each other can be exemplified. According to a second aspect of the present invention, in the bush according to the first aspect, the positioning means includes a fitting portion formed on an elastic member and fitted to a corresponding fitting portion of the housing. To provide a bush.

According to the present invention, since the elastic member and the housing can be directly engaged with each other, positioning can be performed with high precision. Further, the fitting portion can be easily formed on the elastic member. For example, it is only necessary to provide a portion corresponding to the fitting portion in the mold that forms the elastic member. In addition, when a mold is used, the fitting portion can be formed together with the formation of the elastic member, and the cost of forming the fitting portion can be reduced.

According to a third aspect of the present invention, there is provided the bush according to the first or second aspect, wherein the elastic member has a reduced thickness at a part in a circumferential direction. . According to the present invention, since the elastic member has a simple structure in which the thickness of a part of the elastic member is reduced, the load characteristics of the elastic member itself can be stably obtained, which is preferable. The invention according to claim 4 is inserted into a hole of the housing of the steering device.
(3) A mounting structure for a steering device, comprising: the bush according to any one of (3) to (3); and a fixing bolt that passes through the bush and is fixed to a vehicle body.

According to the mounting structure of the present invention, the function and effect of the bush according to any one of claims 1 to 3 can be obtained.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a steering device according to an embodiment of the present invention. FIG. 1 is a partially sectional front view of a mounting structure showing one embodiment of the present invention. FIG.
It is a side view of the principal part of the mounting structure of FIG. Steering device 1
Is a rack and pinion type, for example, a rack shaft 2 that reciprocates to steer wheels (not shown) by movement of a steering wheel (not shown),
And a housing 3 for supporting the rack shaft 2 while accommodating the rack shaft 2 so as to be reciprocally movable in the axial direction. The rack shaft 2 extends in the width direction of the vehicle (in FIG. 1, the direction perpendicular to the plane of the drawing), which is left and right with respect to the traveling direction of the vehicle. ) Is connected to the wheels.

The housing 3 has a cylinder 4 as a main body formed in a cylindrical shape for accommodating the rack shaft 2 and a bracket 5 as a mounting portion surrounding the outer periphery of the cylinder 4. The cylinder 4 and the bracket 5
It is made of metal and is formed separately from each other and is integrally connected. The housing 3 is fixed to the vehicle body fixing portion 6 by the mounting structure 7.
(Only a part is shown in FIG. 1).
The mounting structure 7 includes the bracket 5 of the housing 3 having the mounting hole 8 formed therein and the housing 3 of the steering device 1.
Bush 9 inserted into the hole 8 of the housing 3 to elastically support the
And the fixing portion 6 of the vehicle body into which the fixing bolt 10 is screwed.
And The fixing portion 6 of the vehicle body may be a portion formed integrally with the vehicle body, or may be a member formed separately from the vehicle body and fixed to the vehicle body. A female screw is formed in the fixing portion 6 of the vehicle body, and a male screw of the fixing bolt 10 is screwed into the female screw. The washer 11, the bush 9 and the bracket 5 of the housing 3 are fixed between the fixing part 6 and the head of the fixing bolt 10.

In the mounting structure 7, the hole 8, the bush 9 and the fixing bolt 10 are arranged concentrically, and these axes are arranged orthogonal to the width direction of the vehicle body in which the rack shaft 2 extends. . In the following description, the direction in which the concentric axes of the fixing bolts 10 and the like extend is referred to as the axial direction, and the direction perpendicular to the axial direction is referred to as the radial direction. In particular, the bush 9 of the present invention
A metal cylinder 12 having a hole for inserting the fixing bolt 10, and a cylindrical elastic member 13 integrally formed around the metal cylinder 12 and having different load characteristics according to two different radial directions. Positioning means 14 which engages with the housing 3 to position the elastic member 13 in the circumferential direction.

The positioning means 14 is a fitting portion formed on the elastic member 13 and comprises a concave groove 26 as a concave portion. The concave groove 26 is a corresponding fitting part of the housing 3 and fits with the ridge 33 as a convex part. The positioning means 14 and a mating member provided on the housing 3 with which the positioning means 14 is engaged have holes 8 in the circumferential direction.
A misalignment preventing mechanism for preventing misalignment of the bush 9 in the inside is constituted.

The ridge 33 of the housing 3 is formed on the inner peripheral surface including the peripheral surface of the hole 8. The ridge 33 has a substantially semicircular cross section, extends in the axial direction, protrudes radially inward, and is formed as a single unit. The protrusion 33 is fitted in the above-described concave groove 26 of the elastic member 13 without any gap in the circumferential direction.
The elastic member 13 includes a rubber material such as natural rubber and synthetic rubber. The elastic member 13 has a tubular portion 21 and a pair of annular flanges 22 formed integrally at both ends of the tubular portion 21 in the axial direction and extending in the radial direction. The cylindrical portion 21 includes the housing 3
Is press-fitted into the hole 8, whereby the position is regulated and held in the radial direction. The flange 22 is disposed outside the hole 8, and its position is regulated in the axial direction by the bracket 5 of the housing 3. The inner circumference 24 of the cylindrical portion 21 and the flange 22 is formed of a circumferential surface, is in contact with the outer circumferential surface of the metal tube 12 formed of the circumferential surface, and is fixed to each other.

The cylindrical portion 21 of the elastic member 13 is formed to have an irregular cross section, and has a reduced thickness at a part in the circumferential direction. That is, in the cross-sectional shape cut in the axial direction, the cylindrical portion 21
It has a portion 27 formed in a part in the circumferential direction and having a small thickness measured in the radial direction, and a portion 28 formed in the remaining portion in the circumferential direction excluding the thin portion 27 and having a large thickness in the radial direction. are doing. The thin portions 27 are provided as a pair at positions facing each other across the axis of the elastic member 13. A pair of thin parts 27
Are arranged in the direction in which the rack shaft 2 extends.

The concave groove 26 of the elastic member 13 extends in the axial direction on the outer periphery 23 of the cylindrical portion 21 and the flange 22. The concave groove 26 has a substantially semicircular cross section, and the inside thereof is open outward in the radial direction. The concave groove 26 is formed continuously and singly over the entire length of the elastic member 13 in the axial direction. The concave groove 26 fits with the ridge 33 of the housing 3 at a central portion in the axial direction corresponding to the cylindrical portion 21. On the other hand, both ends of the groove 26 at the axial end are not engaged with the housing 3.

As shown in the sectional view of FIG. 4, both ends of the concave groove 26 formed in the flange 22 are
And may function as the positioning means 14. That is, the peripheral portion 32 of the hole 8 of the housing 3
Alternatively, a protrusion 34 that engages with the end of the concave groove 26 may be formed. As described above, the concave groove 26 of the positioning means 14 may be provided in at least one of the cylindrical portion 21 and the flange 22. The concave groove 26 of the elastic member 13 is
Is provided in the thick portion 28 of the housing 3, and it is preferable to easily secure the depth of the groove and securely engage with the ridge 33 of the housing 3.

Since the concave groove 26 of the elastic member 13 extends in the axial direction, the force applied to the concave groove 26 can be dispersed and received in the axial direction. This is preferable for preventing the elastic member 13 from being damaged. In the mounting structure 7, the ridge 33 of the housing 3 and the concave groove 26 of the elastic member 13 are fitted with each other,
The bush 9 is positioned in the hole 8 toward both sides in the circumferential direction, and is stably held such that the direction in which the pair of thin portions 27 of the elastic member 13 are arranged is parallel to the direction in which the rack shaft 2 extends. .

The elastic member 13 has its inner periphery restricted by the metal tube 12 and its outer periphery restricted by the housing 3 in a press-fit state. In this state, the elastic member 13
As shown in the graph of FIG. 5, the load characteristics are different depending on two radial directions orthogonal to each other. In other words, the load characteristic of the elastic member 13 is determined in the radial direction (the direction in which the rack shaft 2 extends and the width direction of the vehicle body;
reference. 5), a gap is provided between the outer periphery of the thin portion 27 and the inner periphery of the hole 8 so as to provide a relatively soft elastic support so as to increase the amount of deformation under a predetermined load (FIG. 5). Line GX). On the other hand, the load characteristics in the direction in which the thickness of the cylindrical portion 21 is large (the direction orthogonal to the direction in which the rack shaft 2 extends; see arrow Y) are as follows.
Are relatively tightly elastically supported so as to reduce the amount of deformation with respect to the above-described predetermined load (see line GY in FIG. 5). In the direction of arrow X, the elastic coefficient under a small load is smaller than in the direction of arrow Y.

In the radial direction where the thickness of the cylindrical portion 21 becomes thinner, a gap is formed between the outer periphery of the thin portion 27 and the inner periphery of the hole 8. The inner periphery of the hole 8 may be in contact with the hole 8. In this case as well, the load characteristics can be varied due to the difference in wall thickness. Here, the load characteristic is a relation of a deformation amount with respect to a predetermined load, and includes a shape of a graph showing the relation, an elastic coefficient, and the like. Further, if the elastic member 13 has different load characteristics according to at least two different radial directions,
It is preferable to apply the present invention, and can prevent variation in load characteristics.

Since the elastic member 13 is interposed between the steering device 1 and the fixed portion 6 of the vehicle body, vibration, impact, and the like applied to the vehicle body from the wheels via the housing 3 can be reduced. Moreover, due to the directionality of the load characteristics, it is possible to obtain a good steering feeling by increasing the mounting rigidity in the other direction while enhancing the shock absorbing ability in one direction. In the embodiment described above, the positioning means 14 is the concave groove 26, but is not limited to this. For example, the positioning means 14 may be a ridge of the elastic member 13 that fits into the groove of the housing 3. The shape of the ridges and grooves fitted to each other may be a V-shaped cross section or the like in addition to the semicircular cross section described above.
Further, as shown in the cross-sectional view of FIG. 3, the concave groove 26 may be provided at a plurality of positions, for example, at two positions facing each other. The point is that the positioning means 14 is a fitting portion formed on the elastic member 13 as long as the fitting portion can fit with the fitting portion of the housing.

As described above, according to the embodiment of the present invention, the direction of the bush 9 can be set accurately and with high precision with respect to the housing 3 and, consequently, the vehicle body. Can be reduced. Further, since the positioning means 14 includes a fitting portion formed on the elastic member 13 and allows the elastic member 13 and the housing 3 to directly engage with each other, the bush 9 can be positioned with high precision.

Further, the fitting portion can be easily formed on the elastic member 13. For example, it is only necessary to provide a portion corresponding to the fitting portion in the mold forming the elastic member 13. Also,
When using a mold, together with the formation of the elastic member 13,
The fitting portion can also be formed collectively, and the cost of forming the fitting portion can be reduced. Elastic members 13 other than the positioning means 14
And the metal tube 12 can be formed in substantially the same manner as in the prior art. As a result, the bush 13 provided with the positioning means 14
As compared with the conventional bush without the positioning means 14, the increase in cost can be prevented, and the cost can be substantially the same.

In the case of the fitting portion, the housing 3 can be easily formed in the same manner as the elastic member 13 and the cost can be reduced. Since the positioning means 14 of the bush 9 and the pair of fitting portions corresponding to the housing 3 are engaged with each other, the bush 9 is inserted into the hole 8 and when the bush 9 is used after being mounted on the vehicle. 9 is prevented from shifting. Since the pair of fitting portions of the positioning means 14 of the bush 9 and the corresponding portion of the housing 3 are engaged with each other, accurate positioning work is not required, and the work is easy. For example,
The bush 9 may be inserted into the hole 8 of the housing 3 while being aligned to the same degree as in the related art. Further, when the pair of fitting portions are fitted with no gap in the circumferential direction, if the fitting portions are substantially aligned in the circumferential direction, the fitting portions are adjusted when pushed in the axial direction. Fittings are performed with relative displacement in the circumferential direction toward proper positions by the center action. This eliminates the need for accurate positioning of the fitting portions, and simplifies the operation.

Since the elastic member 13 has a simple structure in which the thickness of a part of the elastic member 13 is reduced, the load characteristics of the elastic member 13 itself can be stably obtained, which is preferable. According to the mounting structure 7 of the steering device 1 including the bush 9 of the present invention,
Since the elastic member 13 does not shift with respect to the vehicle body, it is possible to reduce the variation in the mounting rigidity of each individual member due to the position shift of the elastic member 13. Further, it is possible to prevent the steering feeling from deteriorating due to a decrease in the mounting rigidity due to the displacement.

Further, since the fitting portion of the positioning means 14 is provided on the elastic member 13, it is possible to prevent rattling between the fitting portions due to vibration or the like during traveling. In the above-described embodiment, the hole 8 through which the bush 9 passes is formed in the housing 3 in which the bracket 5 and the cylinder 4 are formed separately, but is not limited to this. For example, the housing 3 may be formed integrally with the cylinder 4 and the bracket 5, or may be for a steering device other than the rack and pinion type. In short, the housing 3
In order to fix the steering device to the vehicle body, any member provided in the steering device and having a hole 8 through which the bush 9 is formed may be used.

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 of a mounting structure according to an embodiment of the present invention.

FIG. 2 is a side view of a main part of the mounting structure of FIG.

FIG. 3 is a side cross-sectional view of a mounting structure according to another embodiment of the present invention, showing a cross section corresponding to an AA cross section in FIG.

FIG. 4 is a front view of a mounting structure according to another embodiment of the present invention, showing an enlarged view of a portion corresponding to a portion B in FIG.

5 is a graph of the load characteristics of the bush shown in FIG. 1, in which the vertical axis shows the force and the horizontal axis shows the deformation, and the load characteristics in the X direction in FIG. The load characteristics are shown by a line GY.

[Explanation of symbols]

 Reference Signs List 1 steering device 3 housing 6 fixing part (vehicle body) 7 mounting structure 8 hole 9 bush 10 fixing bolt 12 metal cylinder 13 elastic member 14 positioning means 23 outer periphery of elastic member 26 concave groove (fitting part formed in elastic member) 27 Thin portion (part in the circumferential direction with reduced thickness) 33 Ridge (corresponding fitting part of housing) X, Y Two different radial directions

Claims (4)

[Claims] 1. A bush which is inserted into a hole of a housing for elastically supporting a housing of a steering device on a vehicle body, the bush being formed integrally with a metal cylinder for inserting a fixing bolt, and formed around the metal cylinder. A cylindrical elastic member having different load characteristics according to at least two different radial directions in a state where the outer periphery is constrained; and positioning means for engaging the housing and positioning the elastic member in the circumferential direction. A bush characterized by the following: 2. The bush according to claim 1, wherein said positioning means includes a fitting portion formed on the elastic member and fitted to a corresponding fitting portion of the housing. 3. The bush according to claim 1, wherein said elastic member has a reduced thickness at a part in a circumferential direction. 4. A bush according to claim 1, which is inserted into a hole of a housing of a steering device, and a fixing bolt which passes through the bush and is fixed to a vehicle body. Characteristic mounting structure of steering device.