JP2006189099A - Anti-friction bearing for steering column - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress drop of allowable axial load by preventing increase of bearing torque while making bearing play small. <P>SOLUTION: A plurality of rolling elements 23 (balls) are rollably installed between an inner ring 21 and an outer ring 22, a race surface of the inner ring 21 is formed in a non-perfect round shape, and in a triangular equal diameter deformed circle triangular. Consequently, pre-load is applied when the anti-friction bearing is built between a steering column and a steering shaft. Namely, when the race surface is a non-perfect round shape, rolling elements (balls) loaded on a circumference and rolling elements (balls) not loaded are mixed. Consequently, pre-load is applied partially on the circumference. As results, play of the bearing can be suppressed and simultaneously increase of bearing torque is prevented and drop of allowable axial load can be suppressed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rolling bearing for a steering column for rotatably supporting a steering shaft in the steering column.

  As a steering device for steering the front wheels of an automobile, a steering shaft having a steering wheel fixed to the upper end is conventionally rotatably supported by a pair of upper and lower bearings inside a circular steering column.

The pair of upper and lower bearings have their outer rings fitted and fixed to both upper and lower ends of the steering column, and each inner ring is fitted and fixed to an intermediate portion of the steering shaft. In this way, by mounting the pair of upper and lower bearings so as to span between the inner peripheral surface of both ends of the steering column and the intermediate peripheral surface of the steering shaft, the steering shaft rotates inside the steering column. Only supported freely.
Japanese Patent Laid-Open No. 8-178023 JP 2004-218790 A

  In the above-described conventional steering device, vibration or noise generated from the steering shaft may occur when the vehicle travels.

  This is due to the backlash of the bearing, and if the radial clearance in the rolling bearing is eliminated, the generation of backlash can be suppressed.

  However, if the bearing is used in a negative clearance state with no bearing clearance, torque may increase or the lubrication state may deteriorate.

  In particular, steering column bearings typically use steel pipe housings (steering gorams), which have low inner diameter accuracy, and the variation in bearing residual clearance after bearing press-fitting increases, so there is no negative bearing clearance. If a bearing is used in a gap state, a considerable amount of negative gap setting is required.

  As another method for controlling the bearing play, for example, as disclosed in Patent Document 1 for an idler pulley bearing application, a load is applied to a position offset from the center of the bearing, and the inner and outer rings of the bearing are applied. There has been proposed a method of using the tilted relative to each other.

  However, if the inner ring and the outer ring are used in a relatively inclined state, the rolling elements arranged between the inner ring and the outer ring are driven with different contact angles on the circumference, and the revolution speed of the ball is It will be different depending on the position. As a result, a large load from the ball is applied to the cage, and the cage may be worn or damaged.

  In addition, as a measure for preventing backlash, there has been proposed a method in which a resin ball having a large diameter is mixed in a steel ball on a raceway on the deep groove ball bearing side (Patent Document 2).

  However, since the difference in ball diameter varies depending on the temperature condition due to the difference in the linear expansion coefficient between the resin material and the steel material, it is difficult to set the gap and the usage conditions are limited. Further, since the resin balls are easily elastically deformed with respect to the steel balls, the excessive axial load generated at the time of collision or the like is mainly borne by the steel balls, so that the allowable axial load is reduced.

  The present invention has been made in view of the circumstances as described above, and is a versatile steering system that prevents an increase in bearing torque and suppresses a decrease in allowable axial load while reducing bearing backlash. An object is to provide a rolling bearing for a column.

In order to achieve the above object, a rolling bearing for a steering column according to claim 1 of the present invention is a rolling bearing for a steering column for rotatably supporting a steering shaft in the steering column.
At least the raceway surface of either the outer ring or the inner ring is non-circular, and
When the rolling bearing is incorporated between the steering column and the steering shaft, a preload is applied.

A rolling bearing for a steering column according to claim 2 of the present invention is a rolling bearing for a steering column for rotatably supporting a steering shaft in the steering column.
When the rolling bearing is incorporated between the steering column and the steering shaft, the raceway surface of either the outer ring or the inner ring or both raceways is non-circular and preload is applied. It is characterized by things.

  According to the present invention, at least the raceway surface of either the outer ring or the inner ring is non-circular, and when the rolling bearing is incorporated between the steering column and the steering shaft, Preload is applied.

  That is, when the raceway surface is a non-perfect circle, rolling elements (balls) loaded on the circumference and rolling elements (king) not loaded are mixed.

  Therefore, the preload is partially applied on the circumference. As a result, it is possible to suppress the backlash of the bearing, and at the same time, it is possible to prevent an increase in the bearing torque and to suppress a decrease in the allowable axial load. .

  Hereinafter, a rolling bearing for a steering column according to an embodiment of the present invention will be described with reference to the drawings.

(Embodiment)
Fig.1 (a) is a schematic diagram of the rolling bearing for steering columns which concerns on embodiment of this invention, (b) shows an example of load distribution of a non-round bearing.

  As shown in FIG. 1A, in this embodiment, in the rolling bearing for a steering column, a large number of rolling elements 23 (balls) are interposed between an inner ring 21 and an outer ring 22 so as to be freely rollable. It is.

  The raceway surface of the inner ring 21 is formed in a non-circular shape, and is a triangular equidiameter strain circle. The non-round amount is a value of [circumscribed circle diameter−inscribed circle diameter] in FIG. FIG. 1B shows an example of a load distribution of a non-round bearing.

  However, it goes without saying that the raceway surface of the outer ring 22 or the raceway surfaces of both the inner and outer rings 21 and 22 may be formed in a non-circular shape.

  From the above, in the present embodiment, the raceway surface is formed in a non-circular shape and is a triangular isometric strain circle. Therefore, the rolling bearing is incorporated between the steering column and the steering shaft. In that case, preload is applied.

  That is, when the raceway surface is a non-perfect circle, the rolling elements 23 (balls) loaded on the circumference and the rolling elements 23 (kings) not loaded are mixed.

  Therefore, the preload is partially applied on the circumference. As a result, it is possible to suppress the backlash of the bearing, and at the same time, it is possible to prevent an increase in the bearing torque and to suppress a decrease in the allowable axial load. .

  Non-round bearings themselves are partly used in cylindrical roller bearings mainly to prevent skiding of jet engine main bearings.

(Application example 1 of the present invention)
FIG. 2 is a structural diagram of a steering device that is an application target example 1 of the present invention.

  As a steering device for steering the front wheels of an automobile, a steering shaft 2 having a steering wheel 1 fixed at the upper end is rotatably supported by a deep groove ball bearing 4a and a needle bearing 4b inside a circular steering column 3. Has been.

  The deep groove ball bearing 4 a and the needle bearing 4 b have their outer rings fitted and fixed to both upper and lower ends of the steering column 3, and each inner ring is fitted and fixed to the intermediate portion of the steering shaft 2. Thus, by mounting the deep groove ball bearing 4a and the needle bearing 4b so as to span between the inner peripheral surface of both ends of the steering column 3 and the outer peripheral surface of the intermediate portion of the steering shaft 2, the steering shaft 2 is Only rotation is supported inside the steering column 3.

  When the steering wheel 1 is rotated to give a steering angle to the front wheels, this rotational force is transmitted from the steering shaft 2 to the telescopic transmission shaft 14 via the universal joint 13. The rotation of the transmission shaft 14 is transmitted to an input shaft 16 of a steering gear (not shown) via another universal joint 15. As a result, the steering gear gives a steering angle corresponding to the steering amount of the steering wheel 1 to the front wheels.

  The front / rear position and the vertical position of the steering wheel 1 can be adjusted freely. When adjusting the position, by operating the lever 10, the displacement bracket 12 fixed to the outer peripheral surface of the steering column 3 can be freely displaced with respect to the fixed bracket 11 supported and fixed to the vehicle body side. In this state, the steering wheel 1 is moved to a desired position, and then the lever 10 is moved in the reverse direction to fix the displacement bracket 12 to the fixed bracket 11. As a result, the position of the steering wheel 1 is fixed to the position after movement adjustment.

  As an application object of the present invention, the inner race or the outer race of the deep groove ball bearing 4a and the needle bearing 4b has a raceway surface formed in a non-circular shape, and therefore, between the steering column 3 and the steering shaft 2. When the deep groove ball bearing 4a and the needle bearing 4b are assembled, a preload is applied. That is, when the raceway surface is a non-perfect circle, rolling elements (balls) loaded on the circumference and rolling elements (king) not loaded are mixed. Therefore, the preload is partially applied on the circumference. As a result, it is possible to suppress the backlash of the bearing, and at the same time, it is possible to prevent an increase in the bearing torque and to suppress a decrease in the allowable axial load. .

(Application example 2 of the present invention)
FIG. 3 is a structural diagram of a steering device which is an application target example 2 of the present invention.

  As a steering apparatus for an automobile, a steering shaft includes a solid upper shaft 2a, a hollow middle shaft 2b, and a solid lower shaft 2c. A circular steering column includes an upper column 3a and a lower column. 3b. The upper shaft 2a and the middle shaft 2b are rotatably supported by a deep groove ball bearing 4a and a needle bearing 4b inside the upper column 3a.

  As an application object of the present invention, the inner ring or the outer ring of the deep groove ball bearing 4a and the needle bearing 4b has a non-circular raceway surface. Therefore, the steering column (3a, 3b) and the steering shaft ( 2a, 2b, 2c), when the deep groove ball bearing 4a and the needle bearing 4b are assembled, preload is applied. That is, when the raceway surface is a non-perfect circle, rolling elements (balls) loaded on the circumference and rolling elements (king) not loaded are mixed. Therefore, the preload is partially applied on the circumference. As a result, it is possible to suppress the backlash of the bearing, and at the same time, it is possible to prevent an increase in the bearing torque and to suppress a decrease in the allowable axial load. .

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible.

(A) is a schematic diagram of the rolling bearing for steering columns which concerns on embodiment of this invention, (b) shows an example of load distribution of a non-round bearing. 1 is a structural diagram of a steering device as an application target example 1 of the present invention. FIG. 6 is a structural diagram of a steering device as an application target example 2 of the present invention.

Explanation of symbols

1 Steering wheel 2 Steering shaft 2a Upper shaft 2b Middle shaft 2c Lower shaft 3 Steering column 3
3a Upper column 3b Lower column 4a Deep groove ball bearing 4b Needle bearing 10 Lever 11 Fixed bracket 12 Displacement bracket 13 Universal joint 14 Transmission shaft 15 Another universal joint 16 Input shaft 21 Inner ring 22 Outer ring 23 Rolling element (ball)

Claims (2)

In the steering column rolling bearing for rotatably supporting the steering shaft in the steering column,
At least the raceway surface of either the outer ring or the inner ring is non-circular, and
A rolling bearing for a steering column, wherein a preload is applied when the rolling bearing is incorporated between a steering column and a steering shaft. In the steering column rolling bearing for rotatably supporting the steering shaft in the steering column,
When the rolling bearing is incorporated between the steering column and the steering shaft, the raceway surface of either the outer ring or the inner ring or both raceways is non-circular and preload is applied. This is a rolling bearing for steering columns.

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