JPH0657768U - Bearing device for steering column - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a bearing device for a steering column that exhibits stable friction torque without stick-slip phenomenon or clinging phenomenon, and has vibration absorption that suppresses generation of unpleasant noise. With the goal. [Structure] The steering column bearing device includes a bearing 1 including an outer bush 2 and an inner bush 3, and a ridge 21 is formed on the outer surface of the outer bush 2.
The outer bush 2 and the projection 22 are formed.
An uneven surface portion 25 is formed on the inner surface of the inner bush 3, the inner bush 3 is press-fitted into the uneven surface portion 25 of the outer bush 2 and elastically supported, and the outer bush 2 is press-fitted and fixed in the housing 5, The column shaft 4 is an inner bush 3 elastically supported by the uneven surface portion 25.
It is supported by being given a radial interference.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a steering column bearing device that supports a steering column shaft of an automobile.

[0002]

[Prior art]

 Conventionally, ball bearings or sliding bearings made of synthetic resin have been used as bearings for steering columns that support the steering column shafts of automobiles.

[0003]

[Problems to be solved by the device]

 Generally, the bearings that support the steering column shafts of automobiles are not so severe in terms of rotation conditions such as load and speed, but vibration absorption and friction torque stability to absorb the vibrations acting on the column shafts during idling are required. To be done. Although the friction torque of ball bearings is stable, it is inferior in vibration absorption, and the dimensional accuracy of the housing to which the ball bearing is fixed and the collum shaft supported by the bearing must be finished with high accuracy. In addition to the high price, there is a problem that the processing cost becomes high. Sliding bearings made of synthetic resin are cheaper than the above ball bearings and have the advantage of excellent vibration absorption, but a proper clearance (sliding gap) is required between the sliding bearing and the column shaft. Therefore, there is a problem in that the vibration generated in the column shaft causes a collision noise between the shaft and the bearing, which is transmitted to a person who drives the vehicle as an unpleasant noise. If the clearance between the synthetic resin slide bearing and the shaft is reduced in order to suppress the occurrence of this collision noise, the stick-slip phenomenon may occur, or the bearing may be hugged on the shaft due to changes in the bearing inner diameter caused by temperature changes. And the stability of the friction torque is impaired. The present invention has been made in view of the above circumstances, and a steering column bearing having stable vibration torque without stick-slip phenomenon or clinging phenomenon and vibration absorbing property for suppressing generation of unpleasant noise The purpose is to obtain the device.

[0004]

[Means for Solving the Problems]

 According to the present invention, there is provided a steering column bearing device comprising a bearing, a housing for fixing the bearing, and a column shaft supported by the bearing, wherein the bearing is a rubber elastic body or an elastic synthetic resin. And an inner bush inserted into the inner surface of the outer bush. The outer bush of the outer bush extends in the axial direction and extends in the circumferential direction. A plurality of ridges and protrusions that project outward in the radial direction are formed at opposite positions, and one end opening and an annular step are formed on the inner surface of the outer bush. A concave-convex surface portion continuous with the concave-convex surface portion and a locking ridge portion continuous with the concave-convex surface portion are formed, and the inner bush has a slit groove and is press-fitted into the concave-convex surface portion of the outer bush. The outer bush holding the inner bush is press-fitted into the housing and fixed by fitting the protrusion on the outer surface into the engaging hole formed in the housing. The above object is achieved by a bearing device for a steering column, in which an inner bush elastically supported by the uneven surface portion of the outer bush is supported by a tightening margin in the radial direction.

In the above-mentioned configuration, the uneven surface portion of the outer bush has a mode in which the ring-shaped convex portions and concave portions are alternately formed in the axial direction, or the convex and concave portions extending in the axial direction extend in the circumferential direction. A mode in which they are formed alternately may be adopted. The inner bush having the slit groove is composed of a steel thin plate, a sintered alloy layer integrally bonded to the surface of the steel thin plate, and a synthetic resin layer impregnated into and covering the alloy layer. It is preferable to use a winding bush in which a plate material having a layered structure is wound in a cylindrical shape with the synthetic resin layer inside. Further, it is flexible and tough with the elastic synthetic resin forming the outer bush, and has a Shore hardness (D type) of 40 to 60 and a rebound resilience value (JIS-K6301) of 50 to 80. However, rubber-like elastic behavior remains, and for example, a polyester / ether copolymer or polyurethane is used.

[0006]

[Action]

 Since the inner bush press-fitted into the uneven surface portion of the outer bush is compressed in the radial direction, the column shaft inserted into the inner bush is provided with a radial interference. The column shaft is provided with a tightening margin by the inner bush, and the inner bush is press-fitted into the uneven surface portion of the outer bush, so that between the column shaft and the inner bush and between the inner bush and the uneven surface portion of the outer bush. There is no gap between them. Therefore, the collision noise between the shaft and the inner bush due to the vibration generated in the column shaft does not occur. Further, the vibration generated in the column shaft is absorbed by the inner bush supporting the shaft being supported by the uneven surface portion. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings showing an embodiment thereof.

[0007]

【Example】

 In the figure, reference numeral 1 is a bearing, and the bearing 1 is composed of an outer bush 2 made of a rubber elastic body or a synthetic resin having elasticity, and an inner bush 3 press-fitted and fixed in the outer bush 2.

As shown in FIG. 3 and FIG. 4, the outer bush 2 is radially outward at a position facing the plurality of projections 21 along the entire circumference in the circumferential direction and along the axial direction on the outer surface thereof. The protrusion 22 is formed on the inner surface thereof, and the inner surface thereof has an uneven surface portion 25 along the axial direction having one end opening 23 and an annular step portion 24, and a locking projection portion 26 continuous with the uneven surface portion 25. Has been formed. The locking projections 26 are formed over the entire circumference in the circumferential direction, and the diameter of the locking projections 26 is larger than the inner diameter of the inner bush 3 and smaller than the outer diameter. The diameter formed by the top surface of the convex portion of the irregular surface portion 25 of the outer bush 2 is smaller than the outer diameter of the inner bush 3. In addition, in the embodiment, as shown in FIGS. 3 and 4, the mode in which the locking projections 26 are formed over the entire circumference in the circumferential direction is shown. However, the locking projections 26 are formed in the circumferential direction. It is also possible to adopt a mode in which a plurality of divided pieces are provided all around. Further, the mode in which the ring-shaped convex portions and the concave portions are alternately formed in the concave-convex surface portion 25 in the axial direction has been shown. It is also possible to adopt a mode in which they are formed alternately.

The inner bush 3 has a three-layer structure of a thin steel plate, a sintered metal alloy layer integrally bonded to the surface of the thin steel plate, and a synthetic resin layer impregnated in the alloy layer and covering the alloy layer. It is composed of a winding bush wound in a cylindrical shape with the synthetic resin layer inside. In FIG. 1, reference numeral 31 is an abutting portion of the winding bush, and in this example, a gap 32 between the abutting portions 31 functions as a slit groove.

The inner bush 3 is press-fitted and held in the uneven surface portion 25 on the inner surface of the outer bush 2, whereby a compressive force is applied in the radial direction to form the bearing 1. In this structure, the inner bush 3 has its end faces locked to the annular step portion 24 and the locking projection 26, respectively, so that the inner bush 3 is prevented from slipping out of the outer bush 2.

In the bearing 1 thus configured, the protrusion 22 of the outer bush 2 is fitted into the hole 51 provided in the pipe-shaped housing 5, and the bearing 1 is press-fitted and fixed in the housing 5. When press-fitting and fixing, the plurality of ridges 21 on the outer surface of the outer bush 2 are tightly pressed and fixed to the inner surface of the housing 5, so that the influence of the press-fitting on the inner diameter of the inner bush 3 is prevented as much as possible. . A column shaft 4 is inserted into the inner bush 3 of the bearing 1 to form a bearing device. The column shaft 4 is provided with a tightening margin due to the compressive force of the inner bush 3 provided by press-fitting into the uneven surface portion 25 of the outer bush 2, and is elastically supported by the inner bush 3. Therefore, in a state where no load is applied to the column shaft 4 at the time of idling, the shaft 4 is elastically supported by the inner bush 3, so that the vibration acting on the shaft 4 is absorbed, and the shaft 4 and the shaft 4 are absorbed. The generation of unpleasant noise such as a collision noise generated with the bearing 1 is prevented. The load applied to the shaft 4 during steering operation is supported by the inner bush 2, and the shaft 4 is supported by the bearing 1 with a stable friction torque.

[0012]

[Effect of device]

 In the steering column bearing device of the present invention having the above-described structure, the column shaft is elastically supported by the inner bush with a tightening margin provided by the inner bush, and the inner bush is press-fitted into the uneven surface portion of the outer bush. Therefore, there is no gap between the column shaft and the inner bush and between the inner bush and the uneven surface portion of the outer bush. Therefore, the collision noise between the shaft and the inner bush due to the vibration generated in the column shaft does not occur. Further, the vibration generated in the column shaft is absorbed by the inner bush supporting the shaft being supported by the uneven surface portion.

[Brief description of drawings]

FIG. 1 is a sectional view showing a bearing device for a steering column according to the present invention.

FIG. 2 is a sectional view taken along the line EE of FIG.

FIG. 3 is a cross-sectional view showing an outer bush.

FIG. 4 is a cross-sectional view taken along the line of FIG.

[Explanation of symbols]

 1 Bearing 2 Outer Bushing 3 Inner Bushing 4 Column Shaft 5 Housing 21 Projection 22 Protrusion 25 Concavo-convex surface 26 Locking protrusion

Claims (4)

[Scope of utility model registration request] 1. A bearing device for a steering column comprising a bearing, a housing for fixing the bearing, and a column shaft supported by the bearing, wherein the bearing is made of a rubber elastic body or a synthetic resin having elasticity. And an inner bush inserted into the inner surface of the outer bush, each of which extends along the axial direction on the outer surface of the outer bush, and a plurality of inner bushes are arranged in the circumferential direction. The ridges and the protrusions that project outward in the radial direction are formed at opposite positions. A surface portion and a locking ridge portion connected to the uneven surface portion are formed, and the inner bush is provided with a slit groove and is elastically pressed into the uneven surface portion of the outer bush. The outer bush, which is supported and holds the inner bush, is press-fitted into the housing and fixed by fitting the protrusions on the outer surface into the engaging holes formed in the housing. A bearing device for a steering column, characterized in that an inner bush elastically supported by the uneven surface portion is supported by a radial tightening margin. 2. The steering column bearing device according to claim 1, wherein the uneven surface portion of the outer bush is formed by alternately forming ring-shaped convex portions and concave portions in the axial direction. 3. The bearing device for a steering column according to claim 1, wherein the uneven surface portion of the outer bush is formed by alternately forming convex portions and concave portions extending in the axial direction in the circumferential direction. 4. The inner bush comprises a steel thin plate, a sintered alloy layer integrally bonded to the surface of the steel thin plate, and a synthetic resin layer impregnated into the sintered alloy layer and covering the sintered alloy layer. 4. A plate bush having a three-layer structure, comprising a winding bush wound in a cylindrical shape with the synthetic resin layer inside thereof.
A bearing device for a steering column according to any one of 1.