JP3843205B2 - Steering device mounting structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is, for example, relates to a mounting structure of a vehicle body of an automobile steering system.
[0002]
[Background Art and Problems to be Solved by the Invention]
The mounting structure described above includes a housing of the steering device, a bush fitted in a hole of the housing, and a bolt inserted through the bush and screwed into the vehicle body.
A bush consists of a metal cylinder and the cylindrical rubber material integrally formed in the outer periphery of this metal cylinder. The steering device is elastically supported by 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 strong and the attachment rigidity in other directions is relatively weak.
[0003]
In this case, a bush having a rubber material having a modified cross section is used and is press-fitted into the hole of the housing. However, it is extremely difficult to accurately position the press-fitted bush in the circumferential direction of the hole. This is because irregularly shaped rubber materials tend to move meat in the circumferential direction during press-fitting. 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 increases.
[0004]
An object of the present invention is to solve the technical problems described above, is to provide a mounting structure of the steering apparatus capable of easily reduce variations in the mounting rigidity of each individual.
[0005]
[Means for Solving the Problems and Effects of the Invention]
According to one aspect of the present invention, a bushing is inserted into the hole of the housing for elastically supporting the tubular housing body of the steering system for movably supporting the rack shaft in the axial direction, through the bushing The bush is fixed to the vehicle body, and the bush is formed integrally with a metal tube for inserting the fixing bolt, and at least two different in a state where the outer periphery is constrained by the housing. A cylindrical elastic member having different load characteristics according to two radial directions, and positioning means for engaging the housing to position the elastic member in the circumferential direction . The cylindrical elastic member has a wall thickness. The at least two radial directions are a first radial direction parallel to the axial direction of the rack shaft and orthogonal to the axial direction of the rack shaft. A second radial direction to A gap is formed between the relatively thin portion and the inner periphery of the housing, and the relatively thin portion and the gap face each other in the first radial direction, The positioning means includes a concave portion formed on the outer periphery of the relatively thick portion of the elastic member, and fitted into the corresponding convex portion of the inner periphery of the housing without a gap, the concave portion and the convex portion being the first The amount of deformation of the elastic member with respect to the predetermined load with respect to the first radial direction is relatively larger than the amount of deformation of the elastic member with respect to the predetermined load with respect to the second radial direction. A steering device mounting structure is provided.
[0006]
According to this invention, since the direction of the bush can be set accurately, the variation in the mounting rigidity of the steering device can be reduced .
[0007]
Further, since the elastic member and the housing can be directly engaged with each other by the positioning means, the positioning can be performed with high accuracy. Further, the recess can be easily formed in the elastic member. For example, it is only necessary to provide a portion corresponding to the recess in the mold for forming the elastic member. Moreover, when using a type | mold, a recessed part can be collectively formed with formation of an elastic member, and the formation cost of a recessed part can be made cheap.
[0008]
In addition, the simple structure of reducing the thickness of a part of the elastic member is preferable because the load characteristics of the elastic member itself can be stably obtained .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the attachment structure of the steering apparatus of one Embodiment of this invention is demonstrated.
FIG. 1 is a partial cross-sectional front view of a mounting structure showing an embodiment of the present invention. FIG. 2 is a side view of a main part of the mounting structure of FIG.
The steering device 1 is, for example, of a rack and pinion type, and a rack shaft 2 that reciprocates to steer a wheel (not shown) by movement of a steering wheel (not shown), and the rack shaft 2 And a housing 3 that supports the housing while being housed in an inserted state so as to be capable of reciprocating in the axial direction. The rack shaft 2 extends in the vehicle width direction (in FIG. 1, the direction perpendicular to the plane of the drawing) that is left and right with respect to the traveling direction of the vehicle, and ends of the rack shaft 2 are joints and tie rods (not shown). ) Is connected to the wheel via
[0011]
The housing 3 has a cylinder 4 as a main part formed in a cylindrical shape for accommodating the rack shaft 2, and a bracket 5 as an attachment part surrounding the outer periphery of the cylinder 4. The cylinder 4 and the bracket 5 are made of metal and formed separately from each other, and are integrally connected. The housing 3 is attached to the fixing portion 6 (only a part of which is shown in FIG. 1) by the attachment structure 7.
The mounting structure 7 includes the bracket 5 of the housing 3 in which the mounting hole 8 is formed, the bush 9 inserted into the hole 8 of the housing 3 in order to elastically support the housing 3 of the steering device 1 on the vehicle body, A fixing bolt 10 passing through the bush 9 and a vehicle body fixing portion 6 into which the fixing bolt 10 is screwed are provided. The fixed part 6 of the vehicle body may be a part 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 the male screw of the fixing bolt 10 is screwed into the female screw. A washer 11, a bush 9 and a bracket 5 of the housing 3 are sandwiched and fixed between the fixing portion 6 and the head of the fixing bolt 10.
[0012]
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, which is the direction in which the rack shaft 2 extends.
In the following description, a direction in which concentric axes such as the fixing bolts 10 extend is referred to as an axial direction, and a direction orthogonal to the axial direction is referred to as a radial direction.
In particular, the bush 9 of the present invention has a metal cylinder 12 including a hole for inserting the fixing bolt 10 and different load characteristics according to two different radial directions which are integrally formed around the metal cylinder 12 and are different from each other. A cylindrical elastic member 13 and positioning means 14 for engaging the housing 3 and positioning the elastic member 13 in the circumferential direction are provided.
[0013]
The positioning means 14 is a fitting portion formed in the elastic member 13 and includes a concave groove 26 as a concave portion. The concave groove 26 is a corresponding fitting portion of the housing 3 and fits into the protrusion 33 as a convex portion.
The positioning means 14 and the mating member provided on the housing 3 with which the positioning means 14 engages constitute a misalignment prevention mechanism that prevents misalignment of the bush 9 in the hole 8 in the circumferential direction. .
[0014]
The protrusion 33 of the housing 3 is formed on the inner peripheral surface including the peripheral surface of the hole 8. The protrusion 33 has a substantially semicircular cross section, extends in the axial direction, and protrudes inward in the radial direction, and is formed as a single piece. The protrusion 33 fits into the groove 26 of the elastic member 13 described above with no 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 cylindrical portion 21 and a pair of annular flanges 22 that are integrally formed at both ends of the axial cylindrical portion 21 and extend in the radial direction. The cylinder part 21 is accommodated in the hole 8 of the housing 3 in a press-fitted state, and thereby the position is regulated and held in the radial direction. The flange 22 is disposed outside the hole 8 and is positionally restricted by the bracket 5 of the housing 3 in the axial direction. Moreover, the inner periphery 24 of the cylinder part 21 and the flange 22 consists of a circumferential surface, is in contact with the outer circumferential surface consisting of the circumferential surface of the metal cylinder 12, and is fixed to each other.
[0015]
Moreover, the cylinder part 21 of the elastic member 13 is formed in a cross-sectional shape, and thickness is reduced in a part of the circumferential direction. That is, in the cross-sectional shape cut in the axial direction, the cylindrical portion 21 is formed in a part in the circumferential direction and has a thin part 27 measured in the radial direction, and the remaining part in the circumferential direction excluding the thin part 27 And a portion 28 having a thick radial thickness. A pair of thin portions 27 are provided at positions facing each other across the axis of the elastic member 13. The pair of thin portions 27 are arranged in the direction in which the rack shaft 2 extends.
[0016]
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 its inside is opened outward in the radial direction. The concave groove 26 is continuously formed as a single unit over the entire length of the elastic member 13 in the axial direction. The concave groove 26 is fitted to the protrusion 33 of the housing 3 at the axial center portion corresponding to the cylindrical portion 21. On the other hand, both end portions of the concave groove 26 at the end portion in the axial direction are not engaged with the housing 3.
[0017]
As shown in the sectional view of FIG. 4, both end portions of the concave groove 26 formed in the flange 22 may be engaged with the housing 3 to function as the positioning means 14. That is, a protrusion 34 that engages with the end of the groove 26 may be formed on the peripheral edge 32 of the hole 8 of the housing 3. 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 provided in the thick portion 28 of the elastic member 13, and it is easy to secure the depth of the groove and is preferable for reliably engaging the protrusion 33 of the housing 3.
[0018]
Since the concave groove 26 of the elastic member 13 extends in the axial direction, the force applied thereto can be dispersed and received in the axial direction. As a result, the elastic member 13 made of rubber tends to be weaker than metal. It is preferable to prevent breakage.
In the mounting structure 7, the bushes 9 are positioned toward both sides in the circumferential direction in the hole 8 by fitting the protrusions 33 of the housing 3 and the concave grooves 26 of the elastic member 13 to each other. The pair of thin portions 27 are stably held so that the direction in which the pair of thin portions 27 are aligned is parallel to the direction in which the rack shaft 2 extends.
[0019]
The elastic member 13 is in a press-fitted state, and the inner periphery thereof is restrained by the metal cylinder 12 and the outer periphery thereof is restrained by the housing 3. In this state, the elastic member 13 has different load characteristics according to two radial directions orthogonal to each other, as shown in the graph of FIG.
In other words, the load characteristic of the elastic member 13 is such that the outer circumference of the thin portion 27 and the hole in the radial direction (the direction in which the rack shaft 2 extends and the width direction of the vehicle body, see arrow X) where the thickness of the cylindrical portion 21 is reduced. 8 is provided with a relatively soft elastic support so that a gap is opened between the inner circumference and the inner circumference of FIG. 8 to increase the amount of deformation with respect to a predetermined load (see line GX in FIG. 5). On the other hand, the load characteristic in the direction in which the cylindrical portion 21 is thick (the direction perpendicular to the direction in which the rack shaft 2 extends; see arrow Y) is such that the outer periphery of the thick portion 28 and the inner periphery of the hole 8 are in close contact. The elastic support is relatively rigid so as to reduce the amount of deformation with respect to the predetermined load described above (see line GY in FIG. 5). Further, in the arrow X direction, the elastic coefficient at the time of a small load is made smaller than in the arrow Y direction.
[0020]
Here, the load characteristic is a relationship of the deformation amount with respect to a predetermined load, and includes a shape of a graph showing this relationship, an elastic coefficient, and the like. Moreover, 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 variation in load characteristics can be prevented.
[0021]
By the elastic member 13 being interposed between the steering device 1 and the vehicle body fixing portion 6, vibrations and impacts applied to the vehicle body from the wheels through the housing 3 can be reduced. Moreover, due to the directionality of the load characteristics, it is possible to increase the mounting rigidity in the other direction while improving the shock absorbing ability in one direction and obtain a good steering feeling.
In addition, the shape of the protrusion and the ditch | groove which mutually fit in the above-mentioned embodiment may be V-shaped cross-section other than the above-mentioned semicircular cross-section. Further, as shown in the cross-sectional view of FIG. 3, the concave grooves 26 may be provided at a plurality of locations, for example, at two locations facing each other .
[0022]
As described above, according to the embodiment of the present invention, the direction of the bush 9 can be set accurately and with high accuracy with respect to the housing 3 and, consequently, the vehicle body, so that variation in the mounting rigidity of the steering device 1 for each vehicle can be reduced. .
Further, since the positioning means 14 includes a fitting portion formed on the elastic member 13 and the elastic member 13 and the housing 3 can be directly engaged with each other, the bush 9 can be positioned with high accuracy.
[0023]
Moreover, if it is a fitting part, it can form in the elastic member 13 easily. For example, it is only necessary to provide a portion corresponding to the fitting portion in the mold for forming the elastic member 13. Moreover, when using a type | mold, a fitting part can also be formed collectively with formation of the elastic member 13, and the formation cost of a fitting part can be made cheap. Further, the portion of the elastic member 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 can prevent an increase in cost as compared with a conventional bush without the positioning means 14 and can be made at substantially the same cost.
[0024]
Moreover, if it is a fitting part, it can form easily in the housing 3 similarly to the elastic member 13, and can be made cheap.
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 used after being attached to the vehicle. 9 is prevented from being displaced.
Since the pair of fitting portions between the positioning means 14 of the bush 9 and the corresponding portion of the housing 3 are engaged with each other, an accurate alignment operation is not required and the operation is easy. For example, the bush 9 may be inserted into the hole 8 of the housing 3 while being aligned to the same extent as before. Furthermore, when a pair of fitting parts fit together in the circumferential direction without gaps, the fitting parts can be adjusted when they are pushed in the axial direction if the fitting parts are generally aligned in the circumferential direction. They are fitted while being displaced relative to each other in the circumferential direction toward the appropriate positions by the heart action. Thereby, it is not necessary to accurately align the fitting portions, and the operation can be simplified.
[0025]
Moreover, since the elastic member 13 has a simple structure in which a part of its thickness is reduced, the load characteristic of the elastic member 13 itself can be stably obtained, which is preferable.
Moreover, according to the mounting structure 7 of the steering apparatus 1 provided with the bush 9 of the present invention, the elastic member 13 is not displaced with respect to the vehicle body. Variation can be reduced. Further, it is possible to prevent the steering feeling from deteriorating due to the decrease in the mounting rigidity accompanying the displacement.
[0026]
Moreover, since the fitting part of the positioning means 14 is provided in the elastic member 13, the rattling | fluctuation of fitting parts resulting from the vibration at the time of driving | running | working, etc. can be prevented.
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 separate, but is not limited thereto. 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 may be a member provided in the steering device in which the hole 8 through which the bush 9 is passed is formed in order to fix the steering device to the vehicle body.
[0027]
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 showing an embodiment of the present invention.
FIG. 2 is a side view of the 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 the AA cross section of FIG. 1;
4 is a front view of a mounting structure according to another embodiment of the present invention, and shows an enlarged view of a portion corresponding to part B of FIG.
5 is a graph of the load characteristics of the bush of FIG. 1, in which the vertical axis indicates force, the horizontal axis indicates the amount of deformation, the load characteristic in the X direction in FIG. 2 is represented by a line GX, and the Y direction in FIG. The load characteristic is indicated by a line GY.
[Explanation of symbols]
1 Steering device
2 Rack shaft 3 Housing 6 Fixed part (vehicle body)
7 Mounting structure 8 Hole 9 Bush 10 Fixing bolt 12 Metal cylinder 13 Elastic member 14 Positioning means 23 Outer circumference of elastic member 26 Concave groove ( concave part )
27 thin part minute
28 Thick part 33 Projection ( convex part )
X first radial direction
Y Second radial direction

Claims (1)

A bushing inserted into a hole in the housing to elastically support the cylindrical housing of the steering device that supports the rack shaft movably in the axial direction on the vehicle body ;
It has a fixing bolt that passes through this bush and is fixed to the car body,
The bush is
A metal tube for fixing bolt insertion,
A cylindrical elastic member integrally formed around the metal cylinder and having different load characteristics according to at least two different radial directions in a state where the outer periphery is constrained by the housing;
Positioning means for engaging the housing and positioning the elastic member in the circumferential direction ;
The cylindrical elastic member has a relatively thin portion and a relatively thick portion,
The at least two radial directions include a first radial direction parallel to the axial direction of the rack shaft, and a second radial direction orthogonal to the axial direction of the rack shaft,
A gap is formed between the relatively thin portion and the inner periphery of the housing,
The relatively thin portion and the gap are opposed to the first radial direction,
The positioning means includes a concave portion that is formed on the outer periphery of the relatively thick portion of the elastic member and fits into the corresponding convex portion on the inner periphery of the housing without a gap,
The concave portion and the convex portion are opposed to the second radial direction,
A steering apparatus installation characterized in that a deformation amount of the elastic member with respect to a predetermined load with respect to the first radial direction is relatively larger than a deformation amount of the elastic member with respect to the predetermined load with respect to the second radial direction. Construction.

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