JP2004353803A - Rubber case for steering column bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain uneven abrasion of the outer peripheral surface of a steering shaft by uniforming the surface pressure to the steering shaft. <P>SOLUTION: Comparing the diameter D1 of an inlet side area 22 of a case 10 and the diameter D2 of an inmost area 23, the diameter D2 of the inmost area 23 is formed smaller, whereby the reaction force due to interference of the inmost area 23 is reduced to uniform the surface pressure to the steering shaft 3 in the axial direction of a needle-like roller 26 so that uneven abrasion of the steering shaft 3 due to use can be restrained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a steering column bearing rubber case for holding a steering shaft at a predetermined position of a steering column.
[0002]
[Prior art]
Conventionally, a steering shaft of a vehicle or the like is rotatably supported by a steering column via a needle roller bearing device. As this needle roller bearing device, for example, there is a technique disclosed in Patent Document 1. The needle roller bearing device in this conventional example has an annular case (also referred to as a “rubber case”) that fits inside the column.
[0003]
In particular, as another conventional example of a case in a needle roller bearing device, there is a case having a retaining structure for preventing the case from being axially pulled out of a steering column. As one example of the retaining structure, a technique is known in which an outer peripheral groove is formed in a projection formed to reduce the diameter of a steering column so as to engage in an axial direction.
[0004]
In this case, the outer circumferential groove includes a conical surface disposed on the inlet side of the steering column, a radially extending rising surface disposed on the far side of the steering column, and an annular surface disposed between the conical surface and the rising surface. And
[0005]
The inlet-side region and the back-side region sandwiching the outer circumferential groove are formed to have the same outer diameter, each having a diameter larger than the inner diameter of the steering column. As a result, the inlet side area and the rear side area of the case are mounted on the inner peripheral surface of the steering column with a predetermined amount of elastic interference.
[0006]
[Patent Document 1]
JP-A-56-14623 (page 2, FIG. 1)
[0007]
[Problems to be solved by the invention]
In the case where the outer peripheral groove is formed as described above, the outer peripheral groove has a conical surface on the inlet side of the steering column. For this reason, depending on the axial position where the outer peripheral surface of the inlet side area contacts the steering column, the radial elastic pressing force acting on the needle roller between the inlet side area and the rear side area of the case, that is, the steering column The magnitude of the surface pressure differs. Specifically, the surface pressure is intensively increased on the back side of the case.
[0008]
If the state of generation of the surface pressure differs in the axial direction and the contact state between the case and the steering column becomes uneven in the axial direction, uneven wear occurs on the steering shaft.
[0009]
[Means for Solving the Problems]
The rubber case for a steering column bearing according to the present invention is fitted with a roller bearing that is rotatably supported between the steering column and the steering shaft inserted through the steering column with a predetermined amount of elastic interference, and rotatably supports the steering shaft. And an outer peripheral groove that can be axially locked to a projection provided on the inner peripheral surface of the steering column. The outer peripheral groove sandwiches the outer peripheral groove. The outer peripheral groove is formed in such a shape that a radial elastic pressing force of the one side region on the roller bearing is larger than a radial elastic pressing force of the other side region on the roller bearing. Of the two axial side regions sandwiching the, the interference of at least a part of the one region is smaller than the interference of the other region, It is made different diameters of the outer peripheral surface at the serial one side region and the other side region.
[0010]
Such a rubber case for a steering column bearing is press-fit into the steering column from an inlet opening of the steering column. For example, one side is the axial center side of the steering column, in other words, the back side, and the other side is Is the side of the entrance opening of the steering column.
[0011]
After the rubber case for the steering column bearing is pressed into the steering column, the steering shaft is rotatably supported around the axis by the roller bearing. The pulling out of the steering shaft in the axial direction accompanying the use is prevented by the annular surface of the outer peripheral groove being axially locked to the projection on the inner peripheral surface of the steering column.
[0012]
By the way, the outer circumferential groove has a conical surface whose diameter decreases toward one side, a cylindrical surface further formed on the inner side thereof, and an annular surface which is raised radially outward from a deep portion of the cylindrical surface. Is generally formed in a combination shape.
[0013]
Therefore, when the outer circumferential groove is arranged so that the axial center of the outer circumferential groove coincides with the center of the rubber case for the steering column bearing, the outer circumferential groove has an inclined surface. It is conceivable that the surface pressure, which is a radial elastic pressing force on the roller bearing, differs between the one side region and the other side region of the rubber case for the steering column bearing depending on the axial position to be performed. That is, it is conceivable that the surface pressure on the steering column in one side region becomes larger than the surface pressure in the other side region.
[0014]
However, according to the rubber case for a steering column bearing having the above configuration, at least a part of the interference in the one side area is smaller than the interference in the other area, so that the steering from the roller bearing in the one side area is performed. The surface pressure on the column becomes smaller than the surface pressure on the other side region.
[0015]
Therefore, even if the outer peripheral groove has the above-mentioned shape, the surface pressure on the steering shaft from the roller bearings becomes uniform in the axial direction as a result when the rubber case for the steering column bearing is mounted on the steering column. Is corrected. Therefore, uneven wear of the outer peripheral surface of the steering shaft serving as the inner raceway surface of the rolling element of the roller bearing is suppressed.
[0016]
Further, it is conceivable to control the position of the outer circumferential groove in the axial direction to suppress uneven wear of the outer circumferential surface of the steering shaft, but in this case, it is difficult to determine the axial position of the outer circumferential groove. In contrast, according to the rubber case for a steering column bearing of the present invention, by making the diameter different between the one side region and the other side region, it is possible to easily suppress uneven wear of the outer peripheral surface of the steering shaft. .
[0017]
As a preferred embodiment of the present invention, the outer peripheral surface of the one side region and the other side region is formed in a cylindrical shape, and the diameter of the outer peripheral surface of the entire axial direction of the one side region is equal to the diameter of the entire axial direction of the other side region. It is set smaller than the diameter of the outer peripheral surface.
[0018]
As described above, by setting the diameter of the entire area in the axial direction of the one side area to be smaller than the diameter of the other side area, the interference with the steering column at the time of attachment to the steering column can be reduced. Is smaller in the one side region.
[0019]
Therefore, even if the shape of the outer peripheral groove is the above-mentioned shape, the surface pressure from the roller bearing on the steering shaft is corrected to be uniform in the axial direction when the rubber case for the steering column bearing is mounted on the steering column. Is done.
[0020]
Therefore, uneven wear of the outer peripheral surface of the steering shaft serving as the inner raceway surface of the rolling element of the roller bearing is suppressed.
[0021]
As a further preferred embodiment of the present invention, the outer peripheral surface of the one side region has a diameter larger than the diameter of the other outer peripheral surface of the one side region, and does not exceed the diameter of the outer peripheral surface of the other side region. Is formed.
[0022]
As in this configuration, the interference portion with respect to the steering column is formed by forming an annular portion having a diameter larger than the diameter of the other outer peripheral surface portion and having a diameter not exceeding the diameter of the outer peripheral surface of the other side region. One side region is smaller than the other side region.
[0023]
For this reason, the surface pressure in the axial direction from the roller bearing to the steering shaft is made uniform, and uneven wear of the outer peripheral surface of the steering shaft, which is the inner raceway surface of the roller, is suppressed.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a rubber case for a steering column bearing according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a steering mechanism of an automobile to which a rubber case for a steering column bearing is applied, FIG. 2 is an enlarged sectional view of a main part of FIG. 1, and FIG.
[0025]
Referring to FIG. 1, reference numeral 1 denotes a steering wheel (commonly referred to as a “handle”), 2 denotes a steering column, and 3 denotes a steering wheel that is inserted into a shaft insertion hole 4 of the steering column 2 and transmits steering of the steering wheel 1 to the wheels. Each shows a shaft.
[0026]
Reference numerals 5 and 6 denote a pair of bearing devices. The bearing devices 5, 6 are press-fitted into gaps between the inner peripheral surface of the shaft insertion hole 4 of the steering column 2 and the outer peripheral surface of the steering shaft 3 from inlets on both sides of the steering column 2, and are axially separated from each other. It is located at the place.
[0027]
FIG. 2 shows a bearing device 6 provided on one inlet side (gear box side) of the steering column 2. The bearing device 6 includes a case 10 formed of a material having a predetermined thickness from an elastically deformable material, for example, rubber, and a needle roller bearing 11 as a steering column bearing.
[0028]
An inner circumferential groove 12 along the circumferential direction for mounting the needle roller bearing 11 is formed at an axial center of the inner circumferential surface of the case 10. The needle roller bearing 11 includes an outer ring 25, a plurality of needle rollers 26, and a retainer 28 having pockets 27 for holding the needle rollers 26 at equal circumferential positions.
[0029]
The outer race 25 fits into the inner circumferential groove 12 of the case 10, and the needle rollers 26 have the inner circumferential surface of the outer race 25 as an outer raceway surface and the outer circumferential surface of the steering shaft 3 as an inner raceway surface. .
[0030]
As shown in FIG. 3, an outer circumferential groove 16 is formed in the circumferential direction of the outer circumferential surface of the case 10 so that the protrusion 15 formed on the steering column 2 can be locked and stopped in the axial direction.
[0031]
The cross-sectional shape of the outer circumferential groove 16 is such that a conical surface 17 whose diameter is reduced toward one side, that is, the column depth side, a cylindrical surface 20 formed further on the depth side, and a radially outward direction from the depth side of the cylindrical surface 20. It is formed in a substantially trapezoidal shape from the combination with the annular surface 19 raised up.
[0032]
The projection 15 is formed in a triangular cross section whose diameter is reduced toward the back of the column, and the stepped surface 15a along the radial direction at the innermost portion and the annular surface 19 of the outer circumferential groove 16 are opposed in the axial direction. .
[0033]
The case 10 has one region in the axial direction, i.e., a back region 23, and the other region in the axial direction, i.e., the entrance region 22, via the outer circumferential groove 16. The outer peripheral surface of the inlet-side region 22 is formed as a cylindrical surface having the same diameter in the axial direction, and the outer peripheral surface of the far-side region 23 is formed of the cylindrical surface 21 on the inlet side and the conical surface 18 on the far side. Chamfers 24 are formed at both corners of the case 10.
[0034]
The outer peripheral groove 16 of the case 10 is formed from a combination of surfaces including the conical surface 17 whose diameter is reduced toward the inner side of the column as described above. For this reason, even if the center of the outer peripheral groove 16 coincides with the axial center of the case 10, the outer peripheral surface axial region is projected radially inward on the inlet side region 22 and the inner side region 23. In this case, the outer peripheral surface axial region that comes into contact with the steering column 2 in the entrance side region 22 is a projection region that deviates from the needle rollers 26 toward the entrance side, and the outer peripheral surface axis that comes into contact with the steering column 2 in the rear side portion 22. The direction area is a projection area that covers the needle rollers 26.
[0035]
The diameter D2 of the cylindrical surface 21, which is the maximum diameter of the rear area 23, is formed smaller than the diameter D1 of the inlet area 22 of the case 10. Each of these diameters D1 and D2 is formed larger than the inner diameter of the steering column 2.
[0036]
When the bearing device 6 is mounted on the steering column 2, the steering shaft 3 is supported by the bearing device 6 so as to be rotatable around the axis. Further, the bearing device 6 is in a state of being prevented from rotating by the interference of the case 10.
[0037]
Furthermore, even when the case 10 moves in the axial direction due to the driving operation of the vehicle, the annular surface 19 of the outer circumferential groove 16 of the case 10 abuts on the projection 15 on the inner circumferential surface of the steering column 2 in the axial direction. As a result, the case 10 is prevented from coming off the steering column 2.
[0038]
In this embodiment, the outer peripheral shape of the outer peripheral groove 16 of the case 10 is formed by a combination of surfaces including a conical surface 17 whose diameter is reduced toward the back of the column. For this reason, the outer peripheral surface axial region that comes into contact with the steering column 2 in the entrance-side region 22 is a radial projection region that deviates from the needle rollers 26 toward the entrance side, and the outer peripheral region that comes into contact with the steering column 2 in the back-side portion 22. The area in the plane axis direction is a radial projection area on the needle rollers 26.
[0039]
In this case, if the diameter D1 of the inlet-side region 22 and the diameter D2 of the back-side region 23 are made equal, the reaction force accompanying the interference of the back-side region 23 is large on one axial side of the needle roller 26. Will work. However, in this embodiment, in the case main body 14, the diameter D2 of the rear area 23 is smaller than the diameter D1 of the inlet area 22 and the diameter D2 of the rear area 23.
[0040]
For this reason, even if the case 10 has the outer peripheral groove 16 having the above-described shape, the reaction force due to the interference of the back side region 23 is reduced as compared with the related art, whereby the one side of the needle roller 26 in the axial direction is reduced in diameter. The pressing force in the direction is reduced.
[0041]
Therefore, the surface pressure acting on the outer peripheral surface of the steering shaft 3 from the needle rollers 26 is equalized on both axial sides. For this reason, uneven wear of the steering shaft 3 due to use can be sufficiently suppressed as compared with the related art.
[0042]
In other words, by adjusting the position of the outer circumferential groove 16 on the outer circumferential surface of the case 10 in the axial direction, the control such that the surface pressure acting on the outer circumferential surface of the steering shaft 3 from the needle roller 26 is made uniform in the axial direction. , The surface pressure on the steering shaft 3 can be easily equalized.
[0043]
Although the diameter D2 of the rear side region 23 of the case 10 is smaller than the diameter D1 of the inlet side region 22, the case is described in the case where the locking surface 19 of the case 10 comes into contact with the locking projection 15 of the steering column 2. Even if there is, it is preferable to set the diameter so as not to hinder the removal.
[0044]
Another embodiment will be described with reference to FIGS. FIG. 4 is an enlarged sectional view showing a use state of the case, and FIG. 5 is a sectional view of a single unit of the case.
[0045]
In this embodiment, an annular portion 30 having a small axial width is formed in the rear region 23 of the case 10. The annular portion 30 is formed continuously with the annular surface 19 of the outer peripheral groove 16 formed in the case 10. Further, the diameter D3 of the annular portion 30 is formed substantially equal to the diameter D1 of the inlet-side region 22. The shape and diameter D1 of the inlet side region 22 are the same as those in the above embodiment. The cross-sectional shape of the outer peripheral groove 16 is the same as in the above embodiment.
[0046]
In the rear region 23 of the case 10, the diameter D <b> 4 of a portion farther than the annular portion 30 is set to a value smaller than the inner diameter of the steering column 2. In other words, the only part of the back side region 23 of the case 10 that fits with an interference to the inner peripheral surface of the steering column 2 is the annular part 30 having a narrow axial width. In addition, the outer peripheral surface of the portion on the back side of the annular portion 30 is formed by the cylindrical surface 21 on the inlet side and the conical surface 18 on the back side.
[0047]
In this embodiment, in the case 10, only the annular portion 30 is fitted to the steering column 2 in the rear region 23 with interference. For this reason, even if the outer peripheral groove 16 is shaped such that the surface pressure of the needle roller 26 against the steering shaft 3 is increased on one axial side of the needle roller 26, the shaft of the needle roller 26 The surface pressure on the steering shaft 3 in the direction is consequently equalized in the axial direction. Therefore, uneven wear of the steering shaft 3 accompanying use can be suppressed.
[0048]
In the case of the present embodiment, the diameter D3 of the annular portion 30 is formed substantially equal to the diameter D1 of the inlet-side region 22, so that the inside of the steering column 2 when the case 10 moves in the axial direction. The locking area between the projection 15 on the peripheral surface and the annular surface 19 of the outer peripheral groove 16 of the case 10 can be sufficiently ensured, so that the case 10 can be reliably prevented from coming off. Other configurations are the same as those of the above-described embodiment, and thus the same reference numerals are given and the description is omitted.
[0049]
【The invention's effect】
As is apparent from the above description, according to the present invention, the surface pressure on the steering shaft is made uniform, and uneven wear on the outer peripheral surface of the steering shaft can be suppressed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a steering mechanism to which a case according to an embodiment of the present invention is applied. FIG. 2 is an enlarged sectional view of a main part of FIG. 1 FIG. FIG. 5 is an enlarged sectional view of a main part showing another embodiment. FIG. 5 is a sectional view of a single unit of a rubber case for a steering column bearing.
DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering column 3 Steering shaft 6 Bearing device 10 Case 11 Needle roller bearing 16 Outer peripheral groove 17 Conical surface 19 Annular surface D1 Diameter of case entrance side D2 Diameter of case rear side

Claims (3)

An inner peripheral groove for mounting a roller bearing that is press-fitted with a predetermined amount of elasticity between a steering column and a steering shaft inserted through the steering column, and that rotatably supports the steering shaft; It is formed in a cylindrical shape having an outer peripheral groove that can be locked in the axial direction on a projection provided on the inner peripheral surface of
The outer circumferential groove has a radial elastic pressing force on the roller bearing by one side region, which is larger than a radial elastic pressing force on the roller bearing by the other region, in both axial regions sandwiching the outer circumferential groove. In a rubber case for a steering column bearing formed into a larger shape,
Of the axially opposite side regions sandwiching the outer circumferential groove, at least a part of the one side region is smaller than the interference amount of the other side region, so that the one side region and the other side region have an outer peripheral surface. A rubber case for a steering column bearing having a different diameter. The rubber case for a steering column bearing according to claim 1,
The outer peripheral surface of the one side region and the other side region is formed in a cylindrical shape, and the diameter of the outer peripheral surface of the entire axial direction of the one side region is smaller than the diameter of the outer peripheral surface of the entire axial direction of the other side region. A set rubber case for a steering column bearing. The rubber case for a steering column bearing according to claim 1,
On the outer peripheral surface of the one side region, an annular portion having a diameter larger than the diameter of the other outer peripheral surface of the one side region and having a diameter not exceeding the diameter of the outer peripheral surface of the other side region is formed. Rubber case for steering column bearing.

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