JP2004218790A - Bearing device for steering column - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a steering column capable of realizing both the prevention of rattling or the like of a steering shaft and the resistance to a heavy load applied axially in case of collision of vehicles, although the structure of the device is simple and at low cost. <P>SOLUTION: At least three pieces respectively of resin balls 13 and steel balls 14 which have smaller diameters than that of the balls 13 are arranged in the peripheral direction on a raceway of a deep groove ball bearing. Thus, when the bearing is press-fitted in the inside periphery of the steering column, the radial interval clearance of the bearing can be substantially reduced to zero by minute deformation of the resin balls 13. Even though variation is exhibited in the inside diameter of the steering column, the variation can be absorbed by the resin balls 13. Consequently, the bearing device can prevent occurrence of rattling and anomalous feel of the steering shaft. In the case when a heavy load is applied on the bearing, the steel balls 14 bear the heavy load. <P>COPYRIGHT: (C)2004,JPO&amp;NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device for a steering column mounted on a steering column of an automobile or the like, and more particularly, to a bearing capable of suppressing "rattle" or "scraping" of a steering shaft and maintaining a good operational feeling. Related to the device.
[0002]
[Prior art]
2. Description of the Related Art In an automobile or the like, a steering mechanism including a steering shaft and a universal joint is formed between a wheel and a gear in order to transmit a movement (rotation) of a steering wheel operated by a driver to a steering gear. The steering shaft is rotatably supported by a plurality of bearings disposed between the steering shaft and a steering column disposed around the steering shaft.
[0003]
FIG. 2 is an explanatory view showing an example of a configuration of a steering column portion in a vehicle steering apparatus, and FIG. 3 is an enlarged cross-sectional view around a bearing used in the steering column. The vehicle rear side (right side in the figure) to which the steering wheel is connected will be described as a rear end of a steering column, and the vehicle front side (left side in the figure) will be described as a front end in a steering column.
[0004]
The steering device includes a cylindrical steering column (housing) 1, a steering shaft 2 inserted inside the steering column 1, and a steering shaft 2 interposed between the steering column 1 and the steering shaft 2. (A first bearing 3 at a rear end and a second bearing 4 at a front end) for rotatably supporting the bearing.
[0005]
As shown in FIG. 3, among the bearings 3 and 4 that support the steering shaft 2, the bearing 4 is, as shown in FIG. 3, an outer peripheral surface 2 x of the steering shaft 2 and an inner peripheral surface of a metal cylindrical outer ring (shell) 22. Are arranged between the outer peripheral surface 22x of the outer race 22 and the inner peripheral surface 1y of the steering column 1. 23 are arranged. The spacer ring 23 is provided to absorb variations in the inner diameter of the steering column 1 and is made of an elastic material such as hard rubber or synthetic resin, and is press-fitted and fixed to the inner periphery of the steering column 1. ing.
[0006]
With respect to the bearing device for a steering column having the above-described configuration, the present inventors have made a part of this spacer ring to have a thickness holding part for holding a radial thickness, and to facilitate deformation by reducing the thickness. A proposal has been made for a bearing device that can be easily incorporated into various steering columns having different inner diameters for each manufacturer by using a spacer ring having a thinned portion to be formed (see Patent Document 1). .
[0007]
As a bearing device for such a steering column, a sliding bearing using an elastic bush (see Patent Document 2), a method using a single-row angular ball bearing (see Patent Document 3), and the like have also been proposed. I have.
[0008]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2001-50268 [Patent Document 2] Japanese Utility Model Application Laid-Open No. 6-57768 [Patent Document 3] Japanese Patent Application Laid-Open No. 11-82,500
[Problems to be solved by the invention]
By the way, in the above-described bearing device for a steering column, problems such as abnormal noise / vibration (rattle) generated from the steering shaft during running of the vehicle or deterioration of the steering wheel operation feeling called "go" have been pointed out before. I have.
[0010]
It is considered that the rattling or scraping of the steering shaft is caused by a radial clearance (radial clearance) in the rolling bearing. In particular, in the case of a bearing for a steering column, since this bearing is press-fitted and fixed to the inner periphery of a housing (steering column), it is difficult to manage a radial clearance and a steering column usually made of a steel pipe has a low inner diameter accuracy. In some cases, the radial clearance of the bearing may vary in the circumferential direction due to the variation in the inner diameter of the steering column.
[0011]
In order to solve this problem, conventional bearing devices for steering columns include special bearings in which a spacer ring made of an elastic body is arranged around a plain bearing made of an elastic bush, a single row angular contact ball bearing, or a needle roller bearing. Bearings and the like are employed. However, the method using a plain bearing has the disadvantage of increasing the rotational torque, and the method using an angular contact ball bearing or a special needle roller bearing also has the disadvantage that the structure is complicated and the cost is high. was there.
[0012]
The present invention has been made to address the above-described problems, and has a simple structure and low cost, while preventing rattling of a steering shaft and the like and resistance to a large axial load applied during a vehicle collision. It is an object of the present invention to provide a steering column bearing device capable of satisfying the above requirements.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is a bearing device for a steering column that is interposed between a steering column and a steering shaft and rotatably supports the steering shaft, An outer ring fitted and fixed to the inner periphery of the column, an inner ring fitted to the outer periphery of the steering shaft, a resin ball, and a steel ball smaller in diameter than the resin ball. It is characterized in that three or more steel balls are arranged in the circumferential direction between the outer ring and the inner ring, respectively.
[0014]
Here, it is preferable that the resin balls and the steel balls are alternately arranged in the circumferential direction. (Claim 2)
[0015]
Usually, a steering column bearing has a low rotation speed of a supported steering shaft and a low transmission torque, so that requirements regarding the rotation condition of the bearing are not so high. However, in a shock-absorbing steering device or the like, the entire length of the steering shaft is contracted by the bearing receiving a shock. Therefore, this steering column bearing is also required to have a performance of receiving a large axial load at the time of a collision. Therefore, the present invention provides a steering column bearing that supports a steering shaft, by employing a ball bearing provided with a resin ball that applies a normal radial load and a steel ball that applies an excessive load. The purpose of the period.
[0016]
That is, by arranging three or more resin balls having a diameter larger than that of steel balls on the track of the ball bearing in the circumferential direction, the radial clearance of the bearing is reduced to substantially zero by the minute deformation of the resin balls. It becomes possible to do. In addition, even if the inner diameter of the steering column into which the bearing is press-fitted varies, the resin ball absorbs the variation. Therefore, the bearing device for a steering column of the present invention can prevent rattling or scraping of the steering shaft.
[0017]
On the other hand, when a large load is applied to the bearing in the axial direction, such as at the time of a vehicle collision, three or more small-diameter steel balls arranged in the circumferential direction on the track of the ball bearing are used. A large load is applied to shrink the entire length of a steering shaft of a shock absorbing steering device or the like.
[0018]
The circumferential arrangement of the resin ball and the steel ball is not particularly limited. However, when considering the positions of the load zone and the non-load zone of the radial load in the deep groove ball bearing, the resin ball and the steel ball It is preferable that the balls are arranged at equal intervals in the circumferential direction. Therefore, in this bearing device for a steering column, it is rational to arrange these resin balls and steel balls alternately in the circumferential direction.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view illustrating a configuration of a bearing device for a steering column according to an embodiment of the present invention. The configuration of the entire steering device in which the steering column bearings are arranged is the same as that of the conventional example shown in FIG. 2, and these bearings are composed of a cylindrical steering column (housing) 1 and this steering column 1 And a steering shaft 2 inserted inside the steering shaft. In addition, bearings having the same configuration are used for the two bearings (the first bearing 3 at the rear end and the second bearing 4 at the front end) in the present embodiment.
[0020]
The basic configuration of the steering column bearings (3, 4) in the present embodiment is the same as that of a normal single-row deep groove ball bearing, and a single-row ball formed between an inner ring 12 and an outer ring 11 made of bearing steel. A plurality of balls 13 and balls 14 are arranged on a track. A deep groove type inner raceway groove is formed on the outer peripheral surface 12x of the inner race 12, and a deep groove type outer raceway groove is formed on the inner peripheral surface 11y of the outer race 11 facing the inner race raceway groove. . In the ball raceway formed between the inner raceway raceway groove and the outer raceway raceway groove, resin balls 13 and steel (bearing steel) balls 14 are alternately arranged at predetermined intervals in the circumferential direction. I have. The resin ball 13 is formed using a hard resin material such as a fiber-reinforced polyamide resin, and has a diameter D which is larger than the diameter d of the steel balls 14 arranged adjacent to each other in the circumferential direction. It is formed to be slightly larger. Therefore, as shown in FIG. 1, when these two types of balls are arranged on the same track, the large-diameter resin ball 13 mainly applies a load in the radial direction of the ball bearing.
[0021]
In this ball bearing, similarly to a normal deep groove ball bearing, a retainer (not shown) is arranged in an annular space formed by the inner ring 12 and the outer ring 11, and the resin ball 13, the steel ball 14, Are held at predetermined intervals in the circumferential direction by the cage. The annular space is filled with a lubricant (not shown), and the openings at both ends in the axial direction of the annular space are hermetically sealed by sealing members (not shown) provided in the respective openings. Have been.
[0022]
When the bearing for a steering column having the above configuration is disposed between the steering column 1 and the steering shaft 2, the outer peripheral surface 11 x of the outer ring 11 is press-fitted and fixed to the inner periphery of the steering column 1, and the inner peripheral surface 12 y of the inner ring 12. To rotatably support the steering shaft 2 fitted in the steering shaft 2. At the same time, a radially inward force is applied to the outer ring 11 to the steering column bearing, and the diameter of the outer ring 11 is slightly reduced.
[0023]
However, in this steering column bearing, the resin ball 13 is slightly deformed by the radial force applied to the outer ring 11, and by this action, it is possible to rotate smoothly with the radial clearance of the bearing being zero. It becomes. That is, the bearing device for a steering column according to the present embodiment can prevent rattling or scraping of the steering shaft due to the radial clearance by having the function of absorbing the radial clearance.
[0024]
Also, even when the inner diameter of the steering column 1 into which the bearing is press-fitted varies, the minute deformation of the resin ball 13 has an effect of absorbing the variation, and similarly, the steering shaft rattles and the like. Grit and the like can be prevented.
[0025]
On the other hand, when it is necessary to apply a large axial load applied to this bearing at the time of a vehicle collision or the like, as in a shock absorbing steering device, a small-diameter The steel ball 14 applies this large load to contract the entire length of the steering shaft, thereby ensuring the safety of the occupant.
[0026]
In the above embodiment, an example is shown in which four resin balls and four steel balls are alternately arranged in the circumferential direction on the ball trajectory, respectively. The arrangement is not limited to this example, and the total number of balls may be an odd number, or balls of the same type may be arranged continuously in the circumferential direction. However, considering that it is advantageous to load a radial load during a normal rotation and a large load at the time of a vehicle collision or the like evenly in the circumferential direction, the continuation of the same type of ball in the circumferential direction is 2 times. It is advantageous to arrange the balls of the same kind at equal intervals in the circumferential direction.
[0027]
Further, in the present embodiment, an example is shown in which the steering column bearing of the present invention is used for both of the two bearings (the rear end bearing 3 and the front end bearing 4) that support the steering shaft 2. However, a steering column bearing using this resin ball may be used as one of the bearings on the rear end side or the front end side of the steering shaft 2, and the rear end bearing 3 is the bearing of the present invention. The bearing 4 on the front end side may be a conventional needle bearing.
[0028]
【The invention's effect】
As described above in detail, according to the bearing device for a steering column of the present invention, by providing the bearing itself with a function of absorbing the radial gap, it is possible to prevent the steering shaft from rattling or scraping caused by the radial gap. Can be prevented. On the other hand, when a large load is applied to the bearing in the axial direction, a small-diameter steel ball disposed on the track of the ball bearing applies the large load. This bearing has the same configuration as a normal deep groove ball bearing, and can be manufactured at low cost by using a conventional product for each member other than the resin ball.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a configuration of a steering column bearing according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a configuration of a steering column part in a steering apparatus for an automobile.
FIG. 3 is an enlarged sectional view showing a structure of a steering column bearing (3, 4) in FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Steering column 2 Steering shaft 3, 4 Bearing 5 Steering wheel 6 Universal joint 11 Outer ring 11x Outer peripheral surface 11y Inner peripheral surface 12 Inner ring 12x Outer peripheral surface 12y Inner peripheral surface 13 Resin ball 14 Steel ball 21 Needle roller 22 Outer ring (shell)
23 Spacer ring

Claims (2)

A steering column bearing device interposed between a steering column and a steering shaft to rotatably support the steering shaft,
An outer ring fitted and fixed to the inner periphery of the steering column, an inner ring fitted to the outer periphery of the steering shaft, a resin ball, and a steel ball smaller in diameter than the resin ball; A bearing device for a steering column, wherein three or more balls and steel balls are arranged in the circumferential direction between the outer ring and the inner ring. The bearing device for a steering column according to claim 1, wherein the resin balls and the steel balls are alternately arranged in a circumferential direction.

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