JPH10281151A - Electric ball bearing - Google Patents

Abstract

(57) [Problem] To realize a structure having excellent durability and reliability at low cost. A current-carrying member (10) formed by bending a metal plate is fitted to a base (7) constituting a retainer (6). The outer diameter side and inner diameter side sliding contact portions 1 formed on the current-carrying member 10 are formed.
The steps 4 and 15 are elastically brought into contact with the steps 16 and 17 formed on the outer peripheral surface of the end of the inner race 2 and the inner peripheral surface of the end of the outer race 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The energized ball bearing according to the present invention is incorporated in, for example, a steering device for an automobile, and is used for rotatably supporting a metal steering shaft inside a metal steering column.

[0002]

2. Description of the Related Art A horn switch is required to be provided with a switch for a horn in a steering wheel of an automobile, and electric wiring is provided. This electric wiring is, for example, a cord insulated from a vehicle body. And a ground circuit flowing through the vehicle body. On the other hand, the steering shaft supporting the steering wheel at the upper end is located inside the steering column supported by the vehicle body.
It is rotatably supported via a pair of upper and lower ball bearings.
When the steering shaft and the steering column are made of metal, the ball bearing constitutes a part of the earth circuit. However, when an electric current is applied to the ball constituting the ball bearing, the rolling surface of the ball, and the inner and outer rings Because the raceway surface is electrically corroded,
The durability of the ball bearing is impaired.

For this reason, conventionally, Japanese Utility Model Laid-Open Publication No.
Gazette, Japanese Utility Model Laid-Open No. 1-139123, 4-885
No. 25, No. 6-14547, No. 6-1454
A current-carrying ball bearing such as that described in Japanese Patent Publication No. 8 has been used for a portion through which electricity flows, such as a steering device for an automobile. These conventionally known energized ball bearings are configured such that a metal wire having elasticity is locked in a concave groove formed in an outer peripheral surface of an end of an inner ring and an inner peripheral surface of an end of an outer ring, or a synthetic resin is used. A metal plate is inserted into a part of a cage made of steel when the cage is injection-molded. In the case of these conventional structures, the wire or metal plate electrically connects the inner ring and the outer ring,
The current is prevented from flowing through the ball, and the rolling surface of the ball and the raceway surfaces of the inner and outer rings are prevented from being electrically corroded.

[0004]

In the case of a conventional energized ball bearing having the above-described structure, it is desired to improve the following points. First, in the case of a structure in which a metal wire rod is locked in a concave groove formed in the outer peripheral surface at the end of the inner ring and the inner peripheral surface at the end of the outer ring, for example, a ball bearing is transported from a bearing manufacturer to an automobile manufacturer that assembles a steering device for an automobile. In doing so, there was a possibility that this wire would come off. If the ball bearing from which the wire material has been detached is assembled into a vehicle steering system without being noticed, the durability of the ball bearing is impaired. Also, since the wire rotates with one of the inner ring and the outer ring and slides with respect to the other,
The sliding speed of the sliding portion is high (the sliding amount of the sliding portion per unit time is large), and the sliding portion is easily worn.

On the other hand, in the case of a structure in which a metal plate is inserted into a part of a cage made of a synthetic resin, a manufacturing operation of the cage made of a synthetic resin with a metal plate is troublesome, and not only costs are increased. The cage cannot be shared with a general non-energized ball bearing. For this reason, a cage exclusively for the energized ball bearing is required, and the increase in the number of types of parts also increases the cost. The current-carrying ball bearing of the present invention is designed to solve any of the above-mentioned disadvantages.

[0006]

The energized ball bearing according to the present invention comprises an inner ring having a deep groove type inner raceway on the outer peripheral surface and a deep groove formed on the inner peripheral surface, similarly to a conventionally known energized ball bearing. An outer ring having an outer raceway of a mold, a plurality of balls rotatably provided between the inner raceway and the outer raceway, and a retainer made of synthetic resin for rollingably holding the plurality of balls. And at least one current-carrying member for electrically connecting the inner ring and the outer ring.

[0007] In particular, in the energized ball bearing of the present invention,
The current-carrying member is formed by bending an elastic metal plate, and has a pair of holding plate portions for elastically holding a part of the cage from both sides in the diametrical direction. In addition, these 1
The outer diameter side sliding contact portion is formed by diametrically bending the distal end of the outer diameter side pressing plate portion present on the diametrically outer side of the pair of pressing plate portions so that the inner diameter side pressing plate present on the diametrically inner side. The inner diameter side sliding contact portions are provided by bending the distal end portions of the portions inward in the diameter direction. Then, a part of the retainer is sandwiched from both sides in the diameter direction by the pair of pressing plate parts, and the outer diameter side sliding contact part is held in a state where the energizing member is locked to a part of the retainer. The part elastically abuts on a part of the outer ring that deviates from the outer raceway, and a part of the inner diameter side sliding contact part resiliently contacts with a part of the inner race that deviates from the inner raceway. .

[0008]

In the case of the current-carrying ball bearing of the present invention configured as described above, the inner ring and the outer ring are electrically conducted by the current-carrying member, and most of the current flowing between the outer ring and the inner ring is It passes through the current-carrying member having a small electric resistance. For this reason, the current flowing through the ball becomes small, and electric corrosion does not occur on the rolling surface of the ball and the raceway surface of the inner and outer rings. Further, since the current-carrying member rotates together with the retainer, the sliding speed of the sliding portion between the current-carrying member and the inner and outer rings is about half the relative speed between the inner and outer rings. Therefore, it is possible to stabilize the performance of the current-carrying ball bearing and to improve the durability by suppressing the wear of the sliding portion.

In addition, the current-carrying member is mounted on the retainer by clamping a part of the retainer made of a synthetic resin from both diametrical sides by a pair of outer and inner retaining plates. The production of the cage is not troublesome. In addition, this retainer can be used as a retainer for a general non-conductive type ball bearing unless a part of the conductive member is engaged with the engaging recess.

[0010]

1 and 2 show a first embodiment of the present invention. An inner ring 2 having a deep groove type inner raceway 1 on an outer peripheral surface and an outer ring 4 having a deep groove type outer raceway 3 on an inner peripheral surface are arranged concentrically with each other. A plurality of balls 5, 5 are provided between the inner raceway 1 and the outer raceway 3 so as to roll freely. The plurality of balls 5, 5 are rotatably held by a retainer 6, which is integrally formed by injection-molding a synthetic resin. In the illustrated example, a crown-shaped retainer 6 is used as the retainer 6. This crown-shaped retainer 6 forms concave portions 8, 8 having a partially cylindrical surface or a partially spherical surface on one surface in the axial direction (a back surface in FIG. 1 and a left surface in FIG. 2) of an annular base 7. Elastic claws are provided at the opening edges of the recesses 8, 8.
The portions surrounded by the elastic nail pieces are pockets 9. The balls 5, 5 are pushed into the pockets 9, 9 while elastically widening the interval between the tips of the elastic claw pieces. The balls 5, 5 are held in the pockets 9, 9 so as to roll freely in the pushed state.

At one position in the circumferential direction of the retainer 6,
The inner ring 2 and the outer ring 4 are electrically connected with each other by mounting a current-carrying member 10 made of a thin metal plate having elasticity such as stainless steel spring steel. The current-carrying member 10 is formed by bending the above-described thin metal plate, and has an outer diameter side, an inner diameter side, and a pair of holding plate portions 1.
1 and 12. These pair of holding plate portions 11 and 12
, Elastically sandwiches the base 7 from both sides in the diametrical direction at a portion corresponding to the central portion of one pocket 9 which is a part of the retainer 6. These pair of holding plate portions 11 and 12
Are connected to each other by a connecting portion 13. The outer side surface (the right side surface in FIG. 2) of the connecting portion 13 is a spherical convex surface that matches the inner peripheral surface of the concave portion 8 forming the pocket 9. Further, the pair of holding plate portions 11 and 12 can elastically press the base portion 7 of the retainer 6 from both sides in the diameter direction. Therefore, the interval between the pair of holding plate portions 11 and 12 in the free state is substantially equal to the thickness of the base portion 7 in the diametric direction near the base end (closer to the left end in FIG. 2), and is closer to the front end ( In the portion (close to the right end in FIG. 2), the thickness is slightly smaller than this thickness.

An outer diameter side sliding contact portion 14 is provided at the tip of the outer diameter side pressing plate portion 11 which is present on the outer side in the diameter direction of the pair of pressing plate portions 11 and 12, and the outer diameter side pressing portion is provided. The distal end portion of the plate portion 11 is diametrically outward, and the outer diameter side suppressing plate portion 1
It is formed by bending until the angle between the first and the first is sharp. On the other hand, an inner diameter side sliding contact portion 15 is provided at a distal end portion of the inner diameter side pressing plate portion 12 which is present on the inner side in the diametrical direction. It is formed by bending until the angle with the part 12 becomes an acute angle.

In order to mount the above-described current-carrying member 10 on the holder 6, the current-carrying member 10 must be attached to any of the pockets 9.
The outer-diameter-side pressing plate 11 and the inner-diameter-side pressing plate 12 are elastically deformed in a direction in which their distal ends are separated from each other. 9
To the part corresponding to the central part of the. In the state where the pair of holding plate portions 11 and 12 are externally fitted to the base portion 7 in this manner, the pair of holding plate portions 11 and 12 are connected to the base portion 7 which is a part of the retainer 6. Sandwiched from both sides in the diameter direction,
The current-carrying member 10 is locked to a part of the cage 6. In this manner, in a state where the current-carrying member 10 is locked to the retainer 6, one side of the first half of the outer diameter side sliding contact portion 14 (the upper half left side of FIG. Step 16 formed on the inner peripheral surface at a position closer to the axial end than the outer raceway 3
Abut elastically. Further, one side surface of the first half of the inner diameter side sliding contact portion 15 (the left side surface of the lower half portion in FIG. 2) is a portion closer to the axial end than the inner raceway 1 on the inner peripheral surface of the inner race 2. It elastically contacts the step 17 thus formed.

In the case of the current-carrying ball bearing of the present invention configured as described above, the inner ring 2 and the outer ring 4 are connected to the outer diameter side sliding contact portion 14.
The electrical conduction is performed by the current-carrying member 10 including the inner side sliding contact portion 15. A lubricant such as grease does not exist between the one side surface of the first half of the outer diameter side sliding contact portion 14 and the inner side sliding contact portion 15 and each of the step portions 16 and 17, or even if there is any lubricant. Very slight. Therefore, the electrical resistance of the contact portion between the outer diameter side, the inner diameter side, and each of the sliding contact portions 14 and 15 and the outer peripheral surface of the inner ring 2 and the inner peripheral surface of the outer ring 4 is small. On the other hand, a lubricant film such as grease exists between the rolling surfaces of the balls 5 and the inner raceway 1 and the outer raceway 3. Therefore,
The electrical resistance of the contact portion between the rolling surfaces of these balls 5, 5 and the inner raceway 1 and outer raceway 3 is relatively large. Therefore, most of the current flowing between the outer race 4 and the inner race 2 passes through the current-carrying member 10 including the outer-diameter sliding contact portion 14 and the inner-diameter sliding contact portion 15. Therefore, the current flowing through each of the balls 5, 5 is small, and no electrical corrosion occurs on the rolling surfaces of the balls 5, 5 and the inner raceway 1 and the outer raceway 3.

Further, since the current-carrying member 10 rotates together with the retainer 6, the outer-diameter-side sliding contact portion 14 and the inner-diameter-side sliding contact portion 15 constituting the current-carrying member 10 and the respective step portions 16, 17 are formed.
The sliding speed of the sliding portion (the sliding amount of each contact portion per unit time) is about half of the relative speed between the inner ring 2 and the outer ring 4. Therefore, the wear of each of the sliding portions is suppressed to a small level,
The performance of the energized ball bearing can be stabilized and the durability can be improved.

The current-carrying member 10 holds down a part of the base 7 constituting the synthetic resin-made cage 6 by the outer diameter side and inner diameter side holding plate portions 11 and 12 and the connecting portion 13. As a result, the holder 6 is attached to the holder 6.
The production of is not troublesome. That is, the cage 6 itself constituting the energized ball bearing of the present invention has the same structure as a general crown type cage. Therefore, the cost of the cage 6 does not increase.

Further, after the retainer 6 holding the above-mentioned current-carrying member 10 is incorporated into the ball bearing, the current-carrying member 10 does not fall off the ball bearing. Therefore, the current-carrying member 10 does not come off during transportation, and the durability of this ball bearing is not impaired by incorporating a ball bearing from which the current-carrying member 10 comes off.
Further, the cage 6 can be used as a cage for a general ball bearing that is not energized unless the energizing member 10 is mounted. Therefore, the cage can be shared with a general non-energized ball bearing. For this reason, a cage exclusively for the energized ball bearing is not required, and an increase in the number of types of parts can be suppressed, so that the cost of the energized ball bearing can be prevented from increasing.

Next, FIGS. 3 and 4 show a second example of the embodiment of the present invention. While the structure of the first example described above locks the conducting member 10 at the center of the pocket 9,
In the case of the present example, a current-carrying member 10a is mounted between adjacent pockets 9 in the circumferential direction. Energizing member 1
0a is changed, the current-carrying member 10a
a and 12a, both outer diameter side and inner diameter side holding plates 11a, 12a
And the connecting portion 13a and the outer and inner diameter sliding contact portions 14a and 15
The width of “a” is so narrow that it can be attached to a portion of the base 7 that constitutes the retainer 6 and that is between the adjacent pockets 9. Further, the connecting portion 13a is linearized in accordance with the cross-sectional shape of the base 7 at the mounting position of the conducting member 10a. Other configurations and operations are the same as those of the above-described first example.

In each of the above embodiments, the current-carrying members 10 and 10a are provided only at one position in the circumferential direction of the holder 6. In order to prevent electric erosion on the rolling surfaces of the inner and outer raceways 1,3 and the balls 5,5, when the current is flowed between the inner race 2 and the outer race 4, the energizing member 10, 10
It is sufficient that a is provided only at one location in the circumferential direction. Further, in the case of a ball bearing used at a low speed, such as when incorporated in an automobile steering system, there is no need to particularly consider the rotational balance. Therefore, the current-carrying members 10, 10a are provided only at one location in the circumferential direction. Therefore, even if the rotation balance of the cage 6 is deviated, no inconvenience occurs. On the other hand, when the present invention is applied to an energizing type ball bearing incorporated in a high-speed rotating part such as a rotating shaft support of an electric motor, the above-described energizing member 1 is used.
The rotation balance of the retainer 6 is maintained by arranging 0 and 10a at a plurality of positions in the circumferential direction at equal intervals in the circumferential direction.

[0020]

Since the present invention is constructed and operates as described above, it is possible to realize an inexpensive, low-torque current-carrying ball bearing which is inexpensive, has excellent durability and reliability.

[Brief description of the drawings]

FIG. 1 is a front view showing a first example of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a front view showing a second example of the embodiment of the present invention.

FIG. 4 is a sectional view taken along line BB of FIG. 3;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 inner ring raceway 2 inner ring 3 outer ring raceway 4 outer ring 5 ball 6 retainer 7 base 8 recess 9 pocket 10, 10a conducting member 11, 11a outer diameter side restraining plate part 12, 12a inner diameter side restraining plate part 13, 13a connecting part 14, 14a outer diameter side sliding contact part 15, 15a inner diameter side sliding contact part 16 step 17 step

Claims (1)

[Claims] 1. An inner ring having a deep groove type inner raceway on an outer peripheral surface, an outer ring having a deep groove type outer raceway on an inner peripheral surface, and a plurality of rolls provided between the inner raceway and the outer raceway. Ball, a cage made of a synthetic resin that holds the plurality of balls in a freely rolling manner, and at least one current-carrying member that electrically conducts the inner ring and the outer ring. The current-carrying member is formed by bending an elastic metal plate, and has a pair of holding plate portions for elastically holding a part of the cage from both sides in a diametrical direction. The outer diameter side sliding contact portion is formed by diametrically bending the distal end of the outer diameter side pressing plate portion present on the diametrically outer side of the pair of pressing plate portions so that the inner diameter side pressing plate present on the diametrically inner side. The inner diameter side sliding contact part is provided by bending the tip of the part inward in the diameter direction. A part of the cage is sandwiched from both sides in the diametrical direction by the pair of pressing plates, and the outer diameter side sliding contact is performed with the current-carrying member locked to a part of the cage. A portion of the portion elastically contacts a portion of the outer ring that deviates from the outer ring raceway, and a portion of the inner diameter side sliding contact portion resiliently contacts a portion of the inner ring that deviates from the inner ring raceway. A current-carrying ball bearing characterized by being in contact with it.