JP3747516B2 - Steering column bearing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a steering column bearing for supporting a steering column shaft of an automobile.
[0002]
[Problems to be solved by the invention]
As a bearing for a steering column that supports a steering column shaft of an automobile, a ball bearing or a sliding bearing made of a synthetic resin is used. In general, for bearings that support automobile steering column shafts, rotational conditions such as load and speed are not as severe, but vibration absorption and friction torque that absorb vibrations acting on the column shaft during idling, etc. Stability is required. Although the ball bearing has a stable friction torque, it is inferior in vibration absorption, and it is necessary to finish the dimensional accuracy of the housing to which the ball bearing is fixed and the column shaft supported by the ball bearing with high accuracy. In addition to the high cost of the bearings themselves, there is a problem that the processing cost is also increased.
[0003]
Therefore, Japanese Utility Model Publication No. 61-114122 (Japanese Utility Model Publication No. 1-28338) proposes a synthetic resin bearing provided with an elastic bush. According to this synthetic resin bearing, the steering column shaft is made smooth. In addition, when no load is applied to the steering column shaft during idling or the like, vibrations acting on the steering column shaft can be absorbed, and in addition, the collision of the steering column shaft with the bearing can be absorbed. The hitting sound can be eliminated, and a remarkable effect difficult to obtain with a ball bearing can be achieved.
[0004]
By the way, in the above-mentioned synthetic resin bearing, the mounting of the elastic bush to the synthetic resin bearing is performed by fitting the protrusion formed on the elastic bush into the hole formed in the synthetic resin bearing. It requires alignment, and the outer peripheral surface of the synthetic resin bearing is directly brought into contact with the cylindrical housing so that the synthetic resin bearing is fitted into the cylindrical housing. The effect of tightening of the synthetic resin bearing on the surface directly occurs, and the roundness of the bearing surface changes due to the relaxation of stress during thermal history, and the steering column shaft can be smoothly supported by the bearing surface. There is no fear.
[0005]
The present invention has been made in view of the above points, and the object of the present invention is that it can be easily assembled and can smoothly support the steering column shaft, and can also be used during idling. An object of the present invention is to provide a steering column bearing capable of absorbing vibrations acting on the steering column shaft in a state where no load is applied to the column shaft, and in addition, eliminating the impact sound of the steering column shaft on the bearing.
[0006]
Another object of the present invention is to provide a steering column bearing that can reduce the influence of tightening allowance in fitting into a cylindrical housing and reduce stress relaxation during thermal history. is there.
[0007]
Still another object of the present invention is to provide a steering column bearing capable of preventing the occurrence of rattling and tuning the rotational torque of the steering column shaft.
[0008]
Further, another object of the present invention is that it is not necessary to align the protrusion and the hole, and the bearing body can be firmly fixed to the elastic body, and these are used during use. It is an object of the present invention to provide a steering column bearing that can eliminate the inconvenience such as separation.
[0009]
[Means for Solving the Problems]
According to the present invention, the object includes an elastic body, a bearing body made of synthetic resin, and an elastic ring. The elastic body is formed concentrically with the large-diameter cylindrical portion and the large-diameter cylindrical portion. A small-diameter cylindrical portion, and a connecting portion that connects the large-diameter cylindrical portion and the small-diameter cylindrical portion to each other, and the bearing body has an annular space between the large-diameter cylindrical portion and the small-diameter cylindrical portion of the elastic body. An elastic tongue piece is formed by a cylindrical base portion fitted in place and a plurality of slit grooves formed integrally with one end of the cylindrical base portion and extending to the free end surface along the axial direction. And an elastic ring is a groove formed on the outer peripheral surface of the shaft support portion that faces the shaft support surface. This is achieved by a steering column bearing that is fitted to the steering column.
[0010]
Further, in the present invention, a serration is formed on the outer peripheral surface of the large-diameter cylindrical portion of the elastic body, and in the fitting of the steering column bearing into the cylindrical housing, the shaft bearing surface based on the tightening margin of the elastic body by this serration. It is advisable to reduce the impact on the environment. Also, a plurality of circumferentially arranged projections are integrally formed on the inner circumferential surface of the small-diameter cylindrical portion of the elastic body with a tightening margin with respect to the steering column shaft, and the top surface of this projection is supported by another shaft support. It may be formed as a surface so that rattling does not occur between the steering column shaft and the rotational torque of the steering column shaft can be tuned.
[0011]
In the steering column bearing of the present invention, on the outer peripheral surface of the cylindrical base portion of the bearing body, a protrusion that bites into the large-diameter cylindrical portion of the elastic body is formed, thereby fixing the bearing body firmly to the elastic body, You may make it prevent isolation | separation with the elastic body and bearing main body in use.
[0012]
In a preferred example, the small-diameter cylindrical portion of the elastic body is formed so that the inner diameter thereof is larger than the inner diameter of the shaft-supporting portion defined by the shaft-supporting surface, and the cylindrical base portion of the bearing body has a large-diameter inner peripheral surface and A small-diameter inner peripheral surface that forms a step portion between the large-diameter inner peripheral surface, and the shaft support portion of the bearing body has a frustoconical inner shape that is continuous with the small-diameter inner peripheral surface of the cylindrical base portion. The shaft bearing surface of the shaft bearing portion is formed continuously with the frustoconical inner circumferential surface. Further, the small-diameter cylindrical portion of the elastic body may be arranged such that the outer peripheral surface thereof is fitted to the large-diameter inner peripheral surface of the bearing body and the annular end surface thereof faces the step portion of the bearing body.
[0013]
Examples of materials suitable for use in the elastic body of the present invention include rubber and the like in addition to synthetic resins having elasticity. As a synthetic resin having elasticity, it is flexible and tough, generally has a Shore hardness (D type) of 40 to 60, a rebound resilience value (JIS-K6301) of 50 to 80, and is a rubber-like elasticity. For example, a polyurethane resin, a polyester / ether copolymer resin and the like can be cited as preferable examples.
[0014]
Further, as a material suitable for use in the bearing body, synthetic resins having excellent wear resistance and self-lubricating properties, such as polyacetal resins, polyamide resins, or oil-containing synthetic resins in which a lubricant is contained in these resins are exemplified. be able to.
[0015]
On the other hand, examples suitable for the elastic ring include an O-ring made of rubber or a garter spring.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described in more detail based on preferred examples shown in the drawings. The present invention is not limited to these examples.
[0017]
【Example】
1 to 5, the steering column bearing 1 of this example includes an elastic body 2, a synthetic resin bearing body 3, and an elastic ring 4.
[0018]
The elastic body 2 integrally formed of polyurethane resin includes a large diameter cylindrical portion 11 and a small diameter cylindrical portion 12 that is formed concentrically with the large diameter cylindrical portion 11 and has a slightly shorter axial length than the large diameter cylindrical portion 11. And an annular connecting portion 13 that connects an axial end of the large diameter cylindrical portion 11 and an axial end of the small diameter cylindrical portion 12 to each other. A serration 15 is integrally formed on the entire circumference of the outer circumferential surface 14 of the large-diameter cylindrical portion 11, and is arranged in the circumferential direction on the cylindrical inner circumferential surface 16 at one end of the small-diameter cylindrical portion 12. A plurality of the protrusions 17 in this example are integrally formed. Each of the protrusions 17 is formed with an allowance relative to a steering column shaft 18 that is rotatably supported, and each top surface 19 together with a shaft bearing surface 27 described later, is another member that supports the steering column shaft 18. It is formed as a shaft bearing surface.
[0019]
In this example, the connecting portion 13 is annular so as to connect the annular end of the large diameter cylindrical portion 11 and the annular end of the small diameter cylindrical portion 12 as a whole. It may be provided so as to be connected, and the serrations 15 do not necessarily need to be provided over the entire circumference, and may be provided in the circumferential direction as in the case of the connecting portion 13.
[0020]
The bearing body 3 formed of polyacetal resin includes a cylindrical base portion 22 fitted in an annular space 21 between the large-diameter cylindrical portion 11 and the small-diameter cylindrical portion 12 of the elastic body 2, and one end of the cylindrical base portion 22. Are formed as eight elastic tongue portions 25 by eight slit grooves 24 in this example, which are formed to extend to the free end surface 23 along the axial direction. An inner peripheral surface of the free end 26 includes a shaft support portion 28 formed as a shaft support surface 27. The cylindrical base portion 22 has a cylindrical large-diameter inner peripheral surface 31 and a cylindrical small-diameter inner peripheral surface 33 that forms a stepped portion 32 between the large-diameter inner peripheral surface 31 and a shaft support. The part 28 has a frustoconical inner peripheral surface 34 continuous with the small-diameter inner peripheral surface 33, and the shaft support surface 27 is formed continuously with the frustoconical inner peripheral surface 34. . On the outer peripheral surface 35 of the cylindrical base portion 22, a protrusion 36 that bites into the large-diameter cylindrical portion 11 of the elastic body 2 is formed over the entire circumference. The small-diameter cylindrical portion 12 of the elastic body 2 is arranged with its outer peripheral surface 41 fitted into the large-diameter inner peripheral surface 31 of the bearing body 3 and its annular end surface 42 facing the stepped portion 32 of the bearing body 3. ing. To facilitate the insertion of the cylindrical base portion 22 into the annular space 21, annular tapered surfaces 43 and 44 are formed at the free ends of the small diameter cylindrical portion 12 and the cylindrical base portion 22, respectively.
[0021]
In this example, the small-diameter cylindrical portion 12 and the cylindrical base portion 22 have the inner diameters D1 and D2 defined by the inner peripheral surface 16 and the small-diameter inner peripheral surface 33 of the shaft bearing portion 28 defined by the shaft bearing surface 27. It is formed so as to be larger than the inner diameter D3.
[0022]
The outer peripheral surface 45 of the shaft support 28 may be formed in a frustoconical shape as in the illustrated example, similarly to the inner peripheral surface 34, while the inner peripheral surface 34 is formed as a small-diameter inner peripheral surface 33. It may be formed in a cylindrical shape having the same diameter as or smaller than that. Furthermore, the protrusions 36 do not need to be formed over the entire circumference of the outer peripheral surface 35, and may be provided in the circumferential direction as in the case of the connecting portion 13 and the serration 15.
[0023]
The elastic ring 4 made of a garter spring is fitted in a groove 51 formed in the outer peripheral surface 45 of the shaft support portion 28 that faces the shaft support surface 27, and prevents the diameter of the shaft support portion 28 from being expanded by the elastic ring 4. Thus, there is no gap between the shaft bearing surface 27 and the steering column shaft 18 and an appropriate bearing pressure is applied to the steering column shaft 18 via the shaft bearing surface 27. .
[0024]
The steering column bearing 1 as described above is fitted in the cylindrical housing 61 and used to rotatably support the steering column shaft 18 on the shaft support surface 27 of the bearing body 3. In the present bearing 1, the cylindrical base portion 22 is fitted into the annular space 21 and the elastic body 2 and the bearing body 3 are integrated, so that the structure becomes simple and easy to manufacture and assemble.
[0025]
Moreover, in the bearing 1, the serration 15 is provided on the outer peripheral surface 14 of the large-diameter cylindrical portion 11, so that stress due to the tightening margin of the elastic body 2 in the fitting into the cylindrical housing 61 is absorbed by the deformation of the serration 15. In this case, the roundness of the shaft bearing surface 27 is not deviated, and the relaxation of stress during the heat history of the cylindrical housing 61 that is usually fixed by welding is also absorbed and reduced by the deformation of the serration 15. However, the roundness of the shaft bearing surface 27 is not upset.
[0026]
Further, in a state where no load is applied to the steering column shaft 18 such as during idling, the steering column shaft 18 is elastically supported by the shaft support portion 28 on the shaft support surface 27, so that vibrations acting on the steering column shaft 18 are absorbed. On the other hand, even if strong vibration is applied to the steering column shaft 18, it only collides with the protrusion 17 of the elastic body 2 supported by the cylindrical housing 61 via the serrations 15, so that an unpleasant noise such as a loud collision noise is generated. Can make no sound.
[0027]
In addition, the top surface 19 of the protrusion 17 of the elastic body 2 is brought into contact with the steering column shaft 18 with a margin to prevent rattling from occurring between the steering column shaft 18 and the steering column shaft 18. The rotational torque can be tuned.
[0028]
Further, since the protrusion 36 bites into the large-diameter cylindrical portion 11 of the elastic body 2, the bearing body 3 and the elastic body 2 are firmly connected to each other and are not separated from each other. In the coupling to the elastic body 2, there is no particular need for mutual positioning, and these can be firmly connected to each other with a simple operation.
[0029]
【The invention's effect】
As described above, according to the present invention, the steering column can be easily assembled, and the steering column shaft can be smoothly supported. In addition, in a state where no load is applied to the column shaft during idling or the like, the steering column is The vibration acting on the shaft can be absorbed, and in addition, the impact hitting sound on the bearing of the steering column shaft can be eliminated. In addition, the influence of the tightening allowance can be reduced in the fitting in the cylindrical housing, and the heat can be reduced. The relaxation of stress during history can be reduced. In addition, according to the present invention, it is possible to prevent the occurrence of rattling, to tune the rotational torque of the steering column shaft, and to eliminate the need for alignment between the protrusion and the hole, etc. In addition, the elastic body is firmly fixed to the bearing body, and it is possible to eliminate the inconvenience such as separation of the elastic body during use.
[Brief description of the drawings]
FIG. 1 is a cross-sectional explanatory view of a preferred embodiment of the present invention.
2 is a cross-sectional explanatory view taken along line II-II shown in FIG. 3 of the bearing body shown in FIG.
3 is an explanatory diagram on the right side of the bearing body shown in FIG. 2. FIG.
4 is a cross-sectional explanatory view taken along the line IV-IV shown in FIG. 5 of the elastic body shown in FIG. 1;
FIG. 5 is an explanatory diagram on the right side of the elastic body shown in FIG. 4;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steering-column bearing 2 Elastic body 3 Bearing main body 4 Elastic ring 11 Large diameter cylindrical part 12 Small diameter cylindrical part 13 Connection part 22 Cylindrical base 24 Split groove 25 Elastic tongue piece 27 Shaft bearing surface 28 Shaft bearing part 51 Groove

Claims (8)

An elastic body, a synthetic resin bearing body, and an elastic ring are provided. The elastic body includes a large-diameter cylindrical portion, a small-diameter cylindrical portion formed concentrically with the large-diameter cylindrical portion, and a large-diameter cylinder. A cylindrical base portion that is fitted in an annular space between the large-diameter cylindrical portion and the small-diameter cylindrical portion of the elastic body. And is formed integrally with one end of the cylindrical base portion, and is formed as an elastic tongue piece portion by a plurality of slit grooves formed to extend to the free end surface along the axial direction. For a steering column having a peripheral surface formed as a shaft bearing surface and an elastic ring fitted in a groove formed in the outer circumferential surface of the shaft bearing portion facing the shaft bearing surface bearing. The steering column bearing according to claim 1, wherein serrations are formed on an outer peripheral surface of the large-diameter cylindrical portion of the elastic body. A plurality of protrusions arranged in the circumferential direction are integrally formed on the inner peripheral surface of the small-diameter cylindrical portion of the elastic body, and the top surface of the protrusion is formed as another shaft support surface. A bearing for a steering column according to claim 1 or 2. The steering column bearing according to claim 3, wherein the plurality of protrusions are formed with allowances for a steering column shaft to be supported. The steering column bearing according to any one of claims 1 to 4, wherein a protrusion that bites into a large-diameter cylindrical portion of the elastic body is formed on an outer peripheral surface of the cylindrical base portion of the bearing body. The steering column bearing according to any one of claims 1 to 5, wherein an inner diameter of the small-diameter cylindrical portion is larger than an inner diameter of the shaft support portion defined by the shaft support surface. The cylindrical base portion of the bearing body has a large-diameter inner peripheral surface and a small-diameter inner peripheral surface that forms a stepped portion between the large-diameter inner peripheral surface, and the shaft support portion is a cylindrical base portion. 2. A frustoconical inner peripheral surface that is continuous with the small-diameter inner peripheral surface, and the shaft support surface of the shaft support portion is formed continuously from the frustoconical inner peripheral surface. The steering column bearing according to claim 6. The small-diameter cylindrical portion of the elastic body is arranged such that an outer peripheral surface thereof is fitted to a large-diameter inner peripheral surface of the bearing body and an annular end surface thereof faces a step portion of the bearing body. Steering column bearing.

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