JP7085447B2 - Fixed constant velocity universal joint - Google Patents

Description

The present invention relates to a fixed constant velocity universal joint provided with a sealing device for sealing between an outer joint member and a shaft connected to the inner joint member.

The constant velocity universal joint used as a power transmission mechanism of various industrial machines is generally equipped with a sealing device for preventing foreign matter from entering from the outside and grease from leaking from the inside.

FIG. 4 shows a fixed type (type in which the internal structure is a track offset) constant velocity universal joint using a conventional sealing device. In this constant velocity universal joint, torque is transmitted between the annular outer joint member 51, the annular inner joint member 52 arranged radially inside the outer joint member 51, and the outer joint member 51 and the inner joint member 52. The torque transmission mechanism 53, the shaft 54 that is fitted and fixed in the axial center hole of the inner joint member 52 and protrudes to one side of the inner joint member 52, and the outer joint member 51 and the shaft 54 that protrude from the inner joint member 52. It is provided with a sealing device 55 for sealing between the portions.

The outer joint member 51 is connected and fixed by a bolt 57 to a flange 56 that rotates integrally with a rotating shaft on the driven side (not shown). On the other hand, the end of the shaft 54 on the side opposite to the side fitted with the inner joint member 52 is fixed to the rotary shaft 58 on the drive side by welding. The drive side and the driven side of both rotating shafts can be reversed.

Further, a plurality of track grooves (axial grooves) 51a and 52a are formed on the inner peripheral surface of the outer joint member 51 and the outer peripheral surface of the inner joint member 52 so as to face each other. Then, a plurality of torque transmission balls 59 incorporated between the track groove 51a of the outer joint member 51 and the track groove 52a of the inner joint member 52, and the inner peripheral surface of the outer joint member 51 and the inner joint member 52. The torque transmission mechanism 53 is configured by a cage 60 that is arranged between the outer peripheral surfaces of the above and holds each ball 59 rotatably, and both joints in a state where the outer joint member 51 and the shaft 54 are relatively tilted. Torque transmission between the members 51 and 52 is possible.

The sealing device 55 is formed of a metal inner cylinder portion 61, a metal outer cylinder portion 62, and a flexible material such as rubber or resin, and the inner cylinder portion 61 is in a state of being convex toward the inside of the joint. It is a boot type including a connecting portion 63 for connecting the outer cylinder portion 62 and the outer cylinder portion 62. The inner cylinder portion 61 is fitted to the outer periphery of the protrusion from the inner joint member 52 of the shaft 54, and the outer cylinder portion 62 is provided on one side of the outer joint member 51 to form an annular boot fixing member 64. It is press-fitted and fixed to the inner circumference of. A grease plug 65 for supplying grease to the inside of the joint (between the outer joint member 51 and the inner joint member 52) is attached to the boot fixing member 64.

By the way, some fixed constant velocity universal joints as described above are used in extremely harsh environments. For example, in a continuous casting facility, which is one of the steel facilities, a device used for a roll driving force transmission device that transmits a driving force to various rolls is used in a high temperature and high humidity atmosphere due to radiant heat of 80 ° C. or higher and steam. Receives scattering of corrosive liquids such as chemicals and solid foreign substances such as oxide scale. In such a harsh environment, in the case of the above-mentioned conventional boot-type sealing device, a member made of rubber, resin, or the like deteriorates due to atmospheric temperature or radiant heat, breaks due to scattering of corrosive liquid or solid foreign matter, and the like. It tends to occur and often becomes difficult to use in a short period of time.

On the other hand, as a sealing device, a metal seal inner ring having a convex spherical sealing surface and a metal seal outer ring having a concave spherical sealing surface in relative sliding contact with the sealing surface of the sealing inner ring. It has been proposed to adopt a spherical seal structure composed of a ring so that it can withstand a bad environment (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-96545

However, when a fixed constant velocity universal joint using a sealing device having a spherical sealing structure as described above is to be manufactured based on a product using a conventional boot-type sealing device, in addition to the replacement of the sealing device itself, It is necessary to eliminate the boot fixing member for attaching the outer cylinder part and the grease plug of the conventional sealing device to the outer joint member, and to provide a new structure for attaching the seal inner ring and the grease plug to the outer joint member. There is a drawback that it is not easy to change the specifications from the base product and the manufacturing cost increases considerably.

Therefore, it is an object of the present invention to make it possible to easily change the specifications from a base product using a boot type sealing device in a fixed constant velocity universal joint provided with a sealing device having a spherical sealing structure.

In order to solve the above problems, the present invention transmits torque between the outer joint member, the inner joint member arranged radially inside the outer joint member, and the outer joint member and the inner joint member. Between the torque transmission mechanism to be performed, the shaft that is fitted and fixed in the axial center hole of the inner joint member and protrudes to one side of the inner joint member, and the protrusion between the outer joint member and the inner joint member of the shaft. In a fixed constant velocity universal joint provided with a sealing device for sealing, a boot type sealing device is used as the sealing device, and the boot type sealing device is provided on one side of the outer joint member. Due to the specification change from the base product to be attached in, the sealing device has a seal inner ring having a convex spherical sealing surface and a sealing surface of the seal inner ring instead of the boot type of the base product. It is provided with a seal outer ring having a concave spherical sealing surface that is in relative sliding contact with the shaft, the seal outer ring is externally fitted to a protrusion from the inner joint member of the shaft, and the seal inner ring is the base . The one that is press-fitted into the inner circumference of the seal fixing member that is diverted from the boot fixing member of the product is used .

According to the above configuration, when manufacturing a product using a boot-type sealing device as a base, the boot fixing member for fixing the outer cylinder portion of the base product to the outer joint member is used as it is for sealing. The inner ring can be used as a press-fitting seal fixing member, and the grease plug attached to the boot fixing member of the base product can be used as it is, so a new structure for attaching the seal inner ring and grease plug to the outer joint member. It is not necessary to provide, and it is easy to change the specifications from the base product.

Here, the shaft is provided with an elastic member that urges the seal outer ring toward the seal inner ring, and the concave spherical seal surface of the seal outer ring has a convex spherical shape of the seal inner ring. If the structure is pressed against the sealing surface, the sealing property between the sealing surfaces of the inner ring of the seal and the outer ring of the seal can be improved.

Further, between the inner peripheral surface of the inner ring of the seal and the outer peripheral surface of the shaft, a seal member press-fitted into the inner circumference of the inner ring of the seal and a seal member press-fitted into the outer periphery of the shaft form a shaft. By making the configuration alternately arranged in the direction, even if the outer joint member and the shaft tilt relative to each other, each sealing member does not create a gap between the inner peripheral surface of the inner ring and the outer peripheral surface of the shaft. It is possible to make the specifications follow as such, and it is possible to improve the sealing property of the entire sealing device.

If the inner ring of the seal is provided with at least one protrusion protruding from the inner peripheral surface of the portion to be press-fitted into the seal fixing member, the protrusions of the outer joint member and the inner joint member. The outflow of grease supplied between them to the outer ring side of the seal can be suppressed, and when the seal member is placed between the inner peripheral surface of the inner ring of the seal and the outer peripheral surface of the shaft as described above, the protrusion is used. The seal member can be positioned.

Further, if an outer seal that closes between the seal surfaces of the seal inner ring and the seal outer ring is arranged on the outer peripheral surface of the seal inner ring, foreign matter can be more reliably prevented from entering between the seal surfaces. become able to. Alternatively, the inner ring of the seal has an annular sliding contact having a main body portion to be press-fitted into the seal fixing member and the convex spherical sealing surface, and at least a part thereof is press-fitted into the outer or inner circumference of the main body portion. If it is composed of parts, the contact surface pressure between the inner ring of the seal and the outer ring of the seal is reduced by enlarging the sliding contact portion of the inner ring of the seal and increasing the contact area of the outer ring of the seal with the seal surface. As a result, it is possible to improve the operability (smoothness of the relative tilt of the outer joint member and the shaft) and also improve the sealing performance.

As described above, the fixed constant velocity universal joint of the present invention has a structure in which the inner ring of the seal constituting the sealing device having a spherical seal structure is press-fitted into the annular seal fixing member provided on the outer joint member. When manufacturing a product using a conventional boot-type sealing device as a base, the boot fixing member for attaching the sealing device of the base product can be diverted as the seal fixing member. It is easy to change the specifications from the above, and the increase in manufacturing cost can be suppressed.

Front sectional view of the fixed constant velocity universal joint of the embodiment FIG. 1 is a cross-sectional view showing a modified example of the seal structure between the inner ring of the seal and the outer ring of the seal. FIG. 1 is a cross-sectional view showing another modification of the seal structure between the inner ring of the seal and the outer ring of the seal. Front sectional view of a conventional fixed constant velocity universal joint

Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, this fixed constant velocity universal joint has the same basic configuration as the above-mentioned conventional one, and is arranged inside the annular outer joint member 1 and the outer joint member 1 in the radial direction. One of the annular inner joint member 2, the torque transmission mechanism 3 that transmits torque between the outer joint member 1 and the inner joint member 2, and the inner joint member 2 that is fitted and fixed in the axial center hole of the inner joint member 2. A sealing device 5 for sealing between the shaft 4 projecting to the side and the protruding portion of the outer joint member 1 and the shaft 4 from the inner joint member 2 is provided, and only the structure of the sealing device 5 will be described later. It is different from the conventional one.

The outer joint member 1 is connected and fixed to a flange 6 that rotates integrally with a rotating shaft on the driven side (not shown) with bolts 7. On the other hand, in the shaft 4, the end portion on the side opposite to the side where the inner joint member 2 is fitted is fixed to the rotary shaft 8 on the drive side by welding. The drive side and the driven side of both rotating shafts can be reversed.

Further, a plurality of track grooves (axial grooves) 1a and 2a are formed on the inner peripheral surface of the outer joint member 1 and the outer peripheral surface of the inner joint member 2 so as to face each other. Then, a plurality of torque transmission balls 9 incorporated between the track groove 1a of the outer joint member 1 and the track groove 2a of the inner joint member 2, and the inner peripheral surface of the outer joint member 1 and the inner joint member 2 are used. The torque transmission mechanism 3 is configured by a cage 10 that is arranged between the outer peripheral surfaces of the above and holds each ball 9 rotatably, and both joints in a state where the outer joint member 1 and the shaft 4 are relatively tilted. Torque transmission between members 1 and 2 is possible.

The sealing device 5 has a cylindrical seal inner ring 11 having a convex spherical sealing surface 11a at one end thereof, and a concave spherical sealing surface 12a that is in relative sliding contact with the sealing surface 11a of the seal inner ring 11. A bowl-shaped seal outer ring 12 having a bowl-shaped seal, a coil spring 13 as an elastic member for urging the seal outer ring 12 toward the seal inner ring 11, and a plurality of annular seals arranged inside the seal inner ring 11. It includes a member 14.

The other end of the seal inner ring 11 of the sealing device 5 is press-fitted into the inner circumference of the annular seal fixing member 15 provided on one side of the outer joint member 1. Then, a plurality of protrusions 11b are provided on the inner peripheral surface of the portion to be press-fitted into the seal fixing member 15, and these protrusions 11b are supplied to the inside of the joint (between the outer joint member 1 and the inner joint member 2). Is used for positioning the seal member 14 while suppressing the outflow to the seal outer ring 12 side. It should be noted that at least one of the protrusions may be provided, and the protrusions may be formed in an annular shape.

Further, the seal fixing member 15 is fixed to the outer joint member 1 with a bolt 7 common to the flange 6, and a grease plug 16 for supplying grease from the outside of the joint to the inside of the joint is provided at a position where the seal fixing member 15 does not interfere with the bolt 7. It is screwed in.

The seal outer ring 12 has an annular portion 12b on one end side, and the annular portion 12b is slidably fitted to a protruding portion from the inner joint member 2 of the shaft 4. Then, the coil spring 13 arranged between the seal outer ring 12 and the spring seat 4a formed at one end of the shaft 4 urges the seal outer ring 12 toward the seal inner ring 11 to seal the seal. The concave spherical seal surface 12a of the outer ring 12 is pressed against the convex spherical seal surface 11a of the inner ring 11 to form a spherical seal structure.

Here, the seal inner ring 11 and the seal outer ring 12 are made of metal, and by setting the hardness of the seal inner ring 11 to be about 5 points lower than the seal outer ring 12 in terms of Rockwell hardness, the seal outer ring 12 Wear is suppressed so that sealing and operability are ensured for a long period of time.

The material of the seal inner ring 11 and the seal outer ring 12 is not limited to metal, and a resin such as POM (polyacetal) may be used. If it is made of metal, electroless nickel plating may be applied to improve corrosion resistance. Further, the coil spring 13 may be made of stainless steel in order to improve the corrosion resistance, in addition to the coil spring 13 formed of a general SWP (piano wire).

Each seal member 14 is press-fitted into the inner circumference of the seal inner ring 11 and press-fitted into the outer circumference of the shaft 4 between the inner peripheral surface of the seal inner ring 11 and the outer peripheral surface of the shaft 4. They are arranged so that they are compressed with each other in the axial direction. The amount of axial compression when each seal member 14 is set is set to 30 to 50% of the radial crushing allowance.

The material of the sealing member 14 is a soft rubber such as CR (chloroprene rubber), NR (natural rubber), EP (ethylene / propylene rubber), Si (silicon rubber), FR (fluororubber), UR (urethane rubber). A sponge is used. Then, by setting the seal member 14 formed of such a material in a state of being impregnated with the same type of grease supplied to the inside of the joint or the base oil of the grease, the oil content is transferred to the inner ring 11 of the seal. And 12a of the seal outer ring 12 are inserted between the seal surfaces 11a and 12a, so that good operability is ensured for a long period of time.

The number of the seal members 14 can be three or more, and even in that case, the ones press-fitted into the inner circumference of the inner ring 11 of the seal and the ones press-fitted into the outer periphery of the shaft 4 alternate in the axial direction. Just place it.

This fixed constant velocity universal joint has the above-mentioned configuration, and has a structure in which the seal inner ring 11 constituting the sealing device 5 having a spherical seal structure is press-fitted into the annular seal fixing member 15 provided on the outer joint member 1. Therefore, when manufacturing a product using a conventional boot-type sealing device (see FIG. 4) as a base, a boot fixing member (reference numeral 64 in FIG. 4) for attaching the sealing device of the base product is sealed. It can be diverted as the fixing member 15, and the grease plug (reference numeral 65 in FIG. 4) attached to the boot fixing member of the base product can also be diverted as it is. Therefore, it is not necessary to provide a new structure for attaching the seal inner ring 11 and the grease plug 16 to the outer joint member 1, the specifications can be easily changed from the base product, and the increase in manufacturing cost can be suppressed.

Further, in the spherical seal structure, the concave spherical seal surface 12a of the seal outer ring 12 is pressed against the convex spherical seal surface 11a of the seal inner ring 11 by the elastic force of the coil spring 13, and the seal inner ring is formed. Since the seal member 14 press-fitted into the inner circumference of 11 and the seal member 14 press-fitted into the outer periphery of the shaft 4 are arranged in a state of being compressed with each other in the axial direction, the relative tilt of the outer joint member 1 and the shaft 4 Highly followable to, and good sealing performance can always be ensured.

2 and 3 show modifications of the seal structure between the seal inner ring 11 and the seal outer ring 12. Among them, in the modified example of FIG. 2, the outer seal 17 that closes between the seal surfaces 11a and 12a of the seal inner ring 11 and the seal outer ring 12 is arranged on the outer peripheral surface of one end of the seal inner ring 11 to form a retaining ring. By positioning in the axial direction at 18, it is possible to more reliably prevent foreign matter from entering between the sealing surfaces 11a and 12a. As the material of the outer seal 17, the same material as the seal member 14 inside the inner ring 11 of the seal or POM can be used.

On the other hand, in the modified example of FIG. 3, the seal inner ring 11 is composed of a main body portion 11c press-fitted into the seal fixing member 15 and an annular sliding contact portion 11d having a convex spherical sealing surface 11a, and the sliding contact thereof. It is assumed that a part of the portion 11d is press-fitted into the outer periphery of the small diameter portion formed at one end of the main body portion 11c. According to this configuration, the contact surface pressure between the seal inner ring 11 and the seal outer ring 12 is increased by enlarging the sliding contact portion 11d of the seal inner ring 11 to increase the contact area of the seal outer ring 12 with the seal surface 12a. It is possible to improve the operability by reducing the number of seals and improve the sealing performance. The sliding contact portion 11d of the inner ring 11 of the seal can also be formed of the same material or POM as the seal member 14 inside the inner ring 11 of the seal, similarly to the outer seal 17. Further, at least a part of the sliding contact portion of the inner ring of the seal may be press-fitted into the outer circumference or the inner circumference of the main body portion.

It should be considered that the embodiments disclosed this time are exemplary in all respects and not restrictive. The scope of the present invention is indicated by the scope of claims, not the above-mentioned meaning, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1 Outer joint member 1a Track groove 2 Inner joint member 2a Track groove 3 Torque transmission mechanism 4 Shaft 5 Sealing device 9 Ball 10 Cage 11 Seal inner ring 11a Seal surface 11b Protrusion 11c Main body 11d Sliding contact part 12 Seal outer ring 12a Seal surface 13 Coil spring (elastic member)
14 Seal member 15 Seal fixing member 16 Grease plug 17 Outer seal

Claims (6)

An outer joint member, an inner joint member arranged radially inside the outer joint member, a torque transmission mechanism for transmitting torque between the outer joint member and the inner joint member, and an axial center of the inner joint member. A fixed constant velocity variable equipped with a shaft that is fitted and fixed in a hole and protrudes to one side of the inner joint member, and a sealing device that seals between the outer joint member and the protruding portion of the shaft from the inner joint member. In fittings
Due to a specification change from the base product, a boot type sealing device is used as the sealing device, and the boot type sealing device is attached by an annular boot fixing member provided on one side of the outer joint member.
Instead of the boot type of the base product, the sealing device has a sealing inner ring having a convex spherical sealing surface and a concave spherical sealing surface that is in sliding contact with the sealing surface of the sealing inner ring. The seal outer ring is provided, and the seal outer ring is fitted onto the protrusion from the inner joint member of the shaft, and the seal inner ring is inside the seal fixing member diverted from the boot fixing member of the base product . A fixed constant-velocity universal joint characterized by using a material that is press-fitted into the circumference. The shaft is provided with an elastic member that urges the seal outer ring toward the seal inner ring, and the concave spherical seal surface of the seal outer ring becomes the convex spherical seal surface of the seal inner ring. The fixed constant velocity universal joint according to claim 1, wherein the joint is pressed. Between the inner peripheral surface of the inner ring of the seal and the outer peripheral surface of the shaft, the seal member press-fitted into the inner circumference of the inner ring of the seal and the seal member press-fitted into the outer periphery of the shaft are axially The fixed constant velocity universal joint according to claim 1 or 2, wherein the joints are arranged alternately. The fixed type or the like according to any one of claims 1 to 3, wherein the seal inner ring is provided with at least one protrusion protruding from the inner peripheral surface of a portion to be press-fitted into the seal fixing member. Fast universal joint. The fixed type according to any one of claims 1 to 4, wherein an outer seal that closes between the seal surfaces of the seal inner ring and the seal outer ring is arranged on the outer peripheral surface of the seal inner ring. Constant velocity universal joint. The inner ring of the seal has a main body portion that is press-fitted into the seal fixing member, and an annular sliding contact portion that has a convex spherical seal surface and at least a part of which is press-fitted into the outer periphery or inner circumference of the main body portion. The fixed constant velocity universal joint according to any one of claims 1 to 4, wherein the joint is made of.

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