JP2572038Y2 - Electric corrosion prevention constant velocity universal joint - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a constant velocity universal joint used for power transmission in automobiles and various industrial machines.

[0002]

2. Description of the Related Art Constant velocity universal joints are roughly classified into a fixed type that allows only angular displacement between a drive shaft and a driven shaft, and a sliding type that allows angular displacement and axial displacement. As the fixed type constant velocity universal joint, there are a ball fix joint, an undercut free joint, and the like, all of which use a ball as a torque transmitting member. Examples of the sliding type constant velocity universal joint include a double offset joint using a ball as a torque transmitting member, a cross groove joint, a triball joint, and a tripod joint using a spherical roller as a torque transmitting member.

[0003] In these constant velocity universal joints, torque is transmitted between a drive shaft and a driven shaft through a contact portion between a ball and an inner or outer ring or a contact portion between a spherical roller and an outer ring.

[0004]

Problems to be Solved by the Invention By the way, many electric devices are mounted on automobiles and various industrial machines, and a constant current universal joint is formed by transmitting a leakage current leaking from an electric source or an electric system through a connecting member. There is a possibility that it will flow into. For example, many rolls are used in rolling equipment for feeding a steel sheet, etc., and some of them are driven through a constant velocity universal joint, and when current flows through the constant velocity universal joint, Sparks are generated between the roll and the steel plate, causing electrolytic corrosion on the surface of the steel plate or the roll. Also, the constant velocity universal joint itself generates sparks at contact portions between the guide grooves of the inner and outer races and the balls, thereby causing electrolytic corrosion.

An object of the present invention is to prevent electrolytic corrosion caused by the inflow of such a leakage current.

[0006]

According to a first aspect of the present invention, there is provided a constant velocity universal joint comprising: an outer race having an axial guide groove formed on an inner peripheral surface; an inner race having an axial guide groove formed on an outer peripheral surface; A plurality of balls interposed between the guide groove and the guide groove of the inner ring; and a retainer for holding the ball by being contacted and guided by the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring. And torque transmission via a contact portion between the inner ring and the ball, wherein at least one of at least the surface of the guide groove of the inner ring, the surface of the guide groove of the outer ring, and at least the surface of the ball is formed of an insulating material. And at least the surface of the cage is formed of an insulating material. Here, “at least to the surface” is not limited to the surface formed of an insulating material, but also includes, for example, the entire member formed of an insulating material. The same applies to the following.

A constant velocity universal joint according to a second aspect is the constant velocity universal joint according to the first aspect, wherein the ball is formed of a ceramic material.

According to a third aspect of the present invention, there is provided a constant velocity universal joint comprising: an outer ring having three pairs of axially extending guide grooves formed at circumferentially equally spaced positions on an inner wall surface; And a trunnion member having a spherical roller mounted thereon via a needle roller, and transmitting torque through a contact portion between the guide groove of the outer ring and the spherical roller,
At least one of at least the surface of the guide groove of the outer race, at least the contact surface of the spherical roller, and at least the surface of the needle roller is formed of an insulating material.

A constant velocity universal joint according to a fourth aspect is the constant velocity universal joint according to the third aspect, wherein the spherical roller is formed of a ceramic material.

[0010]

The leakage current which causes electrolytic corrosion is insulated by the member or the surface of the member made of an insulating material.

[0011]

Embodiments of the present invention will be described below.

In the embodiment shown in FIG. 1, the present invention is applied to a sliding type constant velocity universal joint for a rolling mill using a ball 3 as a torque transmitting member. This constant velocity universal joint includes an inner ring 1 having an axial guide groove 1a formed on an outer peripheral surface 1b, an outer ring 2 having an axial guide groove 2a formed on an inner peripheral surface 2b, and a guide groove 1.
The ball 3 is disposed between the inner ring 1 and the inner ring 1 and the inner ring 2b of the outer ring 2 to transmit torque through a contact portion with the guide grooves 1a and 2a. Are held as main components, and a pair of them are connected to each other via an intermediate shaft 8 for use. The outer race 2 of one constant velocity universal joint is flange-coupled to a roll drive shaft 6, and the outer race 2 of the other constant velocity universal joint is flange-coupled to a roll 9. Further, boots 7 are attached to the openings of the respective outer rings 2.

As shown in FIG. 2 in an enlarged manner, in this embodiment, the ball 3 is formed of ceramic, and the inner and outer surfaces of the retainer 5 are coated with ceramic coating films 5a, 5b.
Is formed. However, the coating film is a cage 5
It is sufficient to form them on at least one of the inner and outer surfaces.

The leakage current leaking from the electric system is, for example,
It flows into the constant velocity universal joint via the roll drive shaft 6 and the like, and flows to the roll 9 via a path of the outer ring 2 → ball 3 → the inner ring 1 or the outer ring 2 → the retainer 5 → the inner ring 1. At this time, sparks may be generated at the contact portions between the ball 3 and the guide grooves 1a, 2a, or at the contact portions between the retainer 5 and the outer peripheral surface 1b and the inner peripheral surface 2b, and electric erosion may occur. However, in this constant velocity universal joint, since the ball 3 is formed of ceramic which is an insulating material, and the coating films 5a and 5b of ceramic are formed on the inner and outer surfaces of the retainer 5, the leakage current is reduced. And coating films 5a, 5
It is insulated by b and does not flow to the contact part. Therefore, electric corrosion is unlikely to occur in this constant velocity universal joint. Note that, instead of forming the ball 3 with ceramic, a ceramic coating film may be formed on the surface of the ball 3.
Further, instead of forming the ceramic coating films 5a and 5b on the surface of the retainer 5, the retainer 5 may be formed of ceramic.

In the embodiment shown in FIG. 3, the ball 3 is made of steel, and the surface of the guide groove 1a of the inner ring 1 and the guide groove 2a of the outer ring 2 are formed.
And ceramic coating films 1c and 2c are formed on the surface of the substrate. The leakage current is insulated by the coating films 1c and 2c of the inner and outer rings 1 and 2 and the coating films 5a and 5b of the retainer 5, and does not flow to the contact portions.
It is sufficient that at least one of the coating films 1c and 2c is formed.

In the embodiment shown in FIG. 4, the present invention is applied to a tripod type constant velocity universal joint using the spherical roller 13 as a torque transmitting member. In this constant velocity universal joint, the trunnion member 11 in which the spherical roller 13 is attached to the three legs 11a extending in the radial direction from the circumferentially equidistant position via the needle roller 15 is moved to the circumferentially equidistant position on the inner wall surface. It is housed in the outer ring 12 having three pairs of axial guide grooves 12a formed therein, and the guide grooves 12a and the spherical rollers 13
The torque is transmitted through a contact portion with the spherical surface. The trunnion member 11 is spline-coupled to the shaft 16, and the opening of the outer ring 12 is covered with a boot 17.

As shown in FIG. 5 in an enlarged manner, in this embodiment, a ceramic coating film 12c is formed on the surface of the guide groove 12a.

The leakage current leaked from the electric system is, for example,
Outer ring 12 → Spherical roller 13 → Needle roller 1
5 → flows to the shaft 16 via a path such as the leg 11a. At that time, a spark is generated at a contact portion between the guide groove 12a and the spherical roller 13, a contact portion between the spherical roller 13 and the needle roller 15, and further, a contact portion between the needle roller 15 and the leg 11a. Eating can occur. However, this constant velocity universal joint has a guide groove 12
Since the coating film 12c is formed on the surface of a, the leakage current is insulated by the coating film 12c and does not flow to the contact portion. Therefore, electric corrosion is unlikely to occur in this constant velocity universal joint.

In the embodiment shown in FIG. 6, the spherical roller 13 is formed of ceramic. The leakage current is
It is insulated by the spherical roller 13 and does not flow to the contact portion. Instead of forming the spherical roller 13 with ceramic, a ceramic coating film may be formed on the spherical surface of the spherical roller 13.
Alternatively, the needle roller 15 may be formed of ceramic.

The embodiments described above relate to a sliding type constant velocity universal joint using a ball and a tripod type constant velocity universal joint using a spherical roller. However, the present invention is not limited to this. The present invention can also be applied to other types of constant velocity universal joints, for example, a ball fix joint, a cross groove joint, a triball joint, and the like.

[0021]

[Effects of the Invention] As described above, according to the present invention,
Since the leakage current flowing between the members of the constant velocity universal joint is interrupted by the insulating portion made of the insulating material, the electrolytic corrosion generated at the contact portion between the members is prevented.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a constant velocity universal joint according to an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of FIG.

FIG. 3 is a partially enlarged cross-sectional view showing another embodiment of the present invention.

FIG. 4 is a longitudinal sectional view (FIG. A) and a transverse sectional view (FIG. B) showing a constant velocity universal joint according to another embodiment of the present invention.

FIG. 5 is a partially enlarged transverse sectional view of FIG. 4;

FIG. 6 is a partial enlarged cross-sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner ring 1a Guide groove 1b Outer peripheral surface 1c Ceramic coating film 2 Outer ring 2a Guide groove 2b Inner peripheral surface 2c Ceramic coating film 3 Ball 5 Cage 5a Ceramic coating film 5b Ceramic coating film 11 Trunnion member 11a Leg 12 Outer ring 12a Guide groove 12c Ceramic coating film 13 Spherical roller 15 Needle roller

Claims (4)

(57) [Scope of request for utility model registration] 1. An outer ring having an axial guide groove formed on an inner peripheral surface thereof, an inner ring having an axial guide groove formed on an outer peripheral surface thereof, and a plurality of intermediate rings interposed between the outer ring guide groove and the inner ring guide groove. And a retainer that is held in contact with the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring to hold the ball, and that transmits torque through a contact portion between the guide groove of the inner and outer rings and the ball. Any one of at least a surface of the guide groove of the inner ring, at least a surface of the guide groove of the outer ring, and at least a surface of the ball
An electric corrosion preventing constant velocity universal joint in which the above is formed of an insulating material and at least the surface of the cage is formed of an insulating material. 2. A constant velocity universal joint for preventing electrolytic corrosion according to claim 1, wherein the ball is formed of a ceramic material. 3. An outer race having three pairs of axial guide grooves formed at circumferentially equidistant positions on an inner wall surface, and three legs extending in a radial direction from the circumferentially equidistant position through needle rollers via a needle roller. A trunnion member on which a roller is mounted, and transmits torque through a contact portion between the guide groove of the outer ring and the spherical roller, wherein at least a surface of the guide groove of the outer ring, at least a contact surface of the spherical roller, a needle roller An electrolytic corrosion preventing constant velocity universal joint in which at least one of the surfaces is made of an insulating material. 4. The constant velocity universal joint for preventing electrolytic corrosion according to claim 3, wherein the spherical roller is formed of a ceramic material.