JP2006097758A - Constant velocity joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide constant velocity joint for transmitting the rotation of a driving shaft to a driven shaft at a constant velocity even when there is a mutual axial misalignment between the driving shaft and the driven shaft arranged in parallel, while requiring no grease lubrication and undergoing less restrictions when used. <P>SOLUTION: Two outer rings OR<SB>1</SB>, OR<SB>2</SB>each having an annular space 4 are opposed to each other with their opening ends facing each other. The outer wall face and the inner wall face of the annular space of each of the outer rings OR<SB>1</SB>, OR<SB>2</SB>, three track grooves 5, 6 are provided at a space of 120° extending to the radial direction. At both ends of a joint member J arranged between the opposed portions of the two outer rings OR<SB>1</SB>, OR<SB>2</SB>, cage portions 11 are provided to be inserted to the annular spaces 4. A pocket 12 is formed in each of the cage portions 11, and balls B capable of rolling along the track grooves 5, 6 are incorporated in the pockets 12. The outer rings OR<SB>1</SB>, OR<SB>2</SB>and the joint member J are formed of synthetic resin moldings to require no grease lubrication and reduce the weight of the constant velocity joint. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a constant velocity joint that connects two shafts, a drive shaft and a driven shaft, and transmits the power of the drive shaft to the driven shaft.

  Conventionally, a constant velocity joint has been known as a component for transmitting rotational torque of a drive shaft of an automobile to an axle.

  The constant velocity joint is a member that allows the angular displacement of both shafts while maintaining constant velocity between the drive shaft and the driven shaft, and is therefore frequently used in various industrial machines other than automobiles.

  The constant velocity joint includes a fixed type constant velocity joint that allows only angular displacement and a sliding type constant velocity joint that allows both angular displacement and axial displacement. 1 is known.

  In the constant velocity joint described in Patent Document 1, an inner member is provided on the inner axis of the outer ring to form an annular space, and the axial space extends in at least one of the outer wall surface and the inner wall surface of the annular space. Two track grooves are provided at intervals of 120 ° in the circumferential direction, and a pocket is formed at a position corresponding to the track groove in the cage that is incorporated in the annular space, and a ball that is incorporated in each pocket is provided. Rotating torque is transmitted between the outer ring and the cage via the balls so as to be freely rollable along the track groove.

  By the way, the constant velocity joint can be used when the drive shaft and the driven shaft are relatively inclined, and the two shafts are arranged in parallel with a shift in the axial center. In this case, it is necessary to provide an intermediate shaft between the opposed portion of the drive shaft and the driven shaft, and to install a constant velocity joint between the intermediate shaft and the drive shaft, and between the intermediate shaft and the driven shaft, and torque transmission As the apparatus becomes longer, two constant velocity joints are required, which raises the problem of increased cost.

In order to solve such a problem, two outer rings shown in Patent Document 1 are arranged to face each other so that their open ends face each other, and each of the cage portions provided at both ends of the joint member is placed in the annular space of each outer ring. There has been proposed a constant velocity joint which is inserted and holds a ball for torque transmission in each cage portion.
Japanese Patent Publication No. 52-34699

  By the way, in the conventional constant velocity joint in which the joint member is provided between the two outer rings, the outer ring, the joint member, and various parts of the ball are made of metal such as steel. However, there was a problem that the operation sound was loud, and there was a restriction on the place of use. For example, there have been problems in use for office machines, audio equipment, medical equipment, household appliances, and the like.

  In addition, when used in food production equipment, food is contaminated by the leakage of grease, so it is necessary to take measures to prevent grease leakage by attaching boots, etc., which increases the number of parts and costs. There was a problem of increasing the size.

  It is an object of the present invention to transmit the rotation of the drive shaft to the driven shaft at a constant speed even when there is a shift in the axis between the drive shaft and the driven shaft arranged in parallel, and to lubricate the grease. It is to provide a constant velocity joint that is less subject to restrictions on the use of light weight and small size.

  In order to solve the above-mentioned problems, two outer rings having an annular space with one end opened and facing each other so that the open ends of the annular space face each other, and a cage inserted into the annular space of each outer ring And three track grooves extending in the axial direction on at least one of the outer wall surface and the inner wall surface in the annular space of each outer ring are formed at intervals of 120 ° in the circumferential direction. In the constant velocity joint in which balls that can roll along each track groove are held by each cage portion of the joint member, a configuration is adopted in which each of the outer rings is a synthetic resin molded product.

  In the constant velocity joint according to the present invention, the constant velocity joint can be reduced in weight and a constant velocity joint with smaller operation sound can be obtained by using the joint member as a synthetic resin molded product.

  Further, by applying a preload to the ball, it is possible to obtain a constant velocity joint that is free from backlash in the circumferential direction and excellent in constant velocity.

  Here, when a resin that can be injection-molded is used as the synthetic resin, the outer ring and the joint member can be easily molded, and when a lubricating resin is used, the sliding characteristics are excellent and the operation sound is small. You can get a fast joint.

  As described above, the ball that can roll along the track grooves formed in each of the two outer rings is held by the cage portions provided at both ends of the joint member, so that the joint member relative to each outer ring The axial inclination of the two outer rings can be absorbed by the general inclination, and by connecting one outer ring to the drive shaft and the other outer ring to the driven shaft, the drive shaft and the driven shaft can be mutually connected. Even if there is a deviation of the shaft center, the rotation of the drive shaft can be transmitted to the driven shaft at a constant speed, and a torque transmission device having a short axial length can be obtained.

  In addition, by making each of the two outer rings a molded product, it is possible to obtain a constant velocity joint that is lightweight and has a low operating noise during torque transmission, and grease lubrication is unnecessary. The boot need not be attached, and a small constant velocity joint with a simple structure can be obtained.

  For this reason, it can be used for office machines, audio equipment, medical equipment, household appliances, etc., which have been difficult to use, with few restrictions on use. The degree can be increased, and the size and cost can be reduced.

Embodiments of the present invention will be described below with reference to the drawings. As illustrated, the constant velocity joint according to the present invention includes two outer rings OR ₁ and OR ₂ , a joint member J provided between the outer rings OR ₁ and OR ₂ , and the joint member J and the outer ring OR _1. , OR ₂ and a ball B for transmitting rotational torque between the _two .

The outer rings OR ₁ and OR _{2 each} have a cup portion 1 that is open at one end, and a connecting shaft 2 is integrally provided at the closed end of the cup portion 1. Further, a guide shaft 3 is provided on the central axis in the cup portion 1, an annular space 4 is formed between the guide shaft 3 and the cup portion 1, and the cup portion 1 that forms the outer wall surface of the annular space 4 is provided. Three track grooves 5, 6 extending in the axial direction are provided on the outer peripheral surface of the guide shaft 3 that forms the inner peripheral surface and the inner wall surface of the annular space 4 at intervals of 120 ° in the circumferential direction.

  In the embodiment, the track grooves 5 and 6 are formed on the outer wall surface and the inner wall surface of the annular space 5, respectively, but the track groove may be provided on one of the outer wall surface and the inner wall surface.

The two outer rings OR ₁ and OR ₂ are arranged to face each other so that the opening ends of the cup portion 1 face each other, and the joint member J is assembled between the cup portions 1.

The joint member J has cage portions 11 inserted into the annular spaces 4 of the outer rings OR ₁ and OR ₂ at both ends, and the cage portions 11 are retaining rings 7 attached to the openings of the outer rings OR ₁ and OR _2. It has been retained by. A pocket 12 is formed in the cage portion 11 corresponding to each of the track grooves 5 and 6 of the outer rings OR ₁ and OR ₂ , and the ball B is incorporated in each pocket 12. Each of the balls B is allowed to roll along the track grooves 5 and 6.

As described above, the cage B of the joint member J in which the ball B that can roll along the track grooves 5 and 6 of the _two outer rings OR ₁ and OR ₂ arranged opposite to each other is incorporated between the outer rings OR ₁ and OR _2. When the two outer rings OR ₁ and OR ₂ are misaligned with each other by being held by the portion 11, the joint member J is inclined to absorb the misalignment of the shafts, and the two outer rings OR _1. Thus, a constant velocity joint capable of transmitting torque between the OR ₂ at a constant velocity can be obtained.

  Therefore, by connecting the connecting shaft 2 of one outer ring to the driving shaft and connecting the connecting shaft 2 of the other outer ring to the driven shaft, the driving shaft can be driven even when the driving shaft and the driven shaft are misaligned. Can be transmitted to the driven shaft at a constant speed.

The outer rings OR ₁ and OR ₂ and the joint member J are formed of a synthetic resin molded product. A suitable synthetic resin is selected according to the use conditions of the constant velocity joint, and a synthetic resin that can be injection-molded is desirable. Any resin that can be injection-molded may be a thermoplastic resin or a thermosetting resin.

  There are two types of resin that can be injection-molded: crystalline resin and non-crystalline resin. Either resin can be used, but non-crystalline resin has low toughness and breaks rapidly when torque exceeds the allowable amount. Therefore, it is preferable to use a crystalline resin.

  Preferred synthetic resins include synthetic resins with high lubricating properties, such as polyacetal resins (POM), nylon resins, fluoroplastics such as PFA, FEP, and ETFE, injection moldable polyimide resins, and polyphenylene sulfide resins (PPS). , Wholly aromatic polyester resins, polyether ether ketone resins (PEEK), polyamideimide resins, and the like.

  Each of these resins may be used alone or a polymer alloy in which two or more kinds are mixed. Or the polymer alloy which mix | blended said synthetic resin with the synthetic resin with low lubrication characteristics other than the above may be sufficient.

  Moreover, even a synthetic resin having low lubricating properties can be used by enhancing the lubricating properties by adding a solid lubricant or lubricating oil. Examples of the solid lubricant include polytetrafluoroethylene, graphite, and molybdenum disulfide.

  Further, glass fiber, carbon fiber, various mineral fibers (whiskers) may be added to the synthetic resin to increase the strength, or may be used in combination with a solid lubricant or the like.

  The most suitable materials for use in the present invention are POM, nylon resin, PPS, and PEEK. The nylon resin may be nylon 6, nylon 66, nylon 610, nylon 612, nylon 11, nylon 12, nylon 46, semi-aromatic nylon having an aromatic ring in the molecular chain, or the like. Since POM, nylon resin, and PPS are relatively inexpensive with excellent heat resistance and lubricity, a constant velocity joint with excellent cost performance can be obtained.

  Moreover, PEEK is excellent in mechanical strength and lubricity even if a reinforcing material and a lubricant are not blended, so that a high-performance constant velocity joint can be obtained.

As described above, by using the outer rings OR ₁ and OR ₂ and the joint member J as molded articles of synthetic resin, it is possible to obtain a constant velocity joint that is light in weight and has a low operating noise during torque transmission, and grease. Lubrication can be eliminated. Further, since it is not necessary to lubricate the grease, it is not necessary to install a boot, and a small constant velocity joint having a simple structure with a small number of parts can be obtained.

  For this reason, there are few restrictions on use, and it can be used for various kinds of equipment such as food production equipment.

  As the ball B, a ball of bearing steel, stainless steel, ceramics, synthetic resin, or the like can be used. When the constant velocity joint is used for a medical device or a food production machine, it is preferable to use a ball B made of stainless steel or ceramics because environmental concerns are eliminated. By using the ball B as a synthetic resin, it is possible to obtain a constant velocity joint that is further excellent in weight reduction and noise reduction. In order to give a hygienic impression, it is preferable to use a white resin as the synthetic resin forming the outer ring and the like. POM is optimal because it is white and has high lubricity and can be made grease-free.

In the embodiment, the outer rings OR ₁ and OR ₂ and the joint member J are molded products of synthetic resin, but only the outer rings OR ₁ and OR ₂ may be molded products of synthetic resin.

Further, in the outer rings OR ₁ and OR ₂ , the cup portion 1 and the connecting shaft 2 are integrally formed of synthetic resin, but the connecting shaft 2 is formed of ceramics, steel, stainless steel, aluminum alloy or the like, and the cup portion 1 You may make it couple | bond with.

As shown in the embodiment, when the outer rings OR ₁ and OR ₂ are formed of a synthetic resin, a preload can be applied to the ball B using the elasticity of the outer rings OR ₁ and OR ₂ . Specifically, preload is applied to the ball B by making the inner diameter between the track groove 5 formed on the inner periphery of the cup portion 1 and the track groove 6 formed on the outer periphery of the guide shaft 3 smaller than the ball diameter of the ball B. Can be granted. As a result, it is possible to obtain a constant velocity joint that is free from backlash in the circumferential direction and has excellent constant velocity.

  Further, by forming three split grooves extending in the axial direction from the opening end between the track groove 5 and the track groove 5 of any one cup part 1, the cup part 1 is divided into three in the circumferential direction. An elastic piece that can be elastically deformed in the radial direction of the cup portion 1 can be formed between adjacent split grooves. With such a structure, when a rotational torque greater than the rotational torque allowable by the elastic modulus of the outer ring is applied, each elastic piece elastically deforms outward in the radial direction of the cup portion 1, and the outer ring OR and the joint Torque transmission between the members J can be cut off. For this reason, a function as a torque limiter can be added to the constant velocity joint, and an effect can be obtained in preventing breakage of the constant velocity joint.

  In addition, the elastic piece formed from the above-mentioned split groove can also be formed in order to apply a preload to the ball B using the elastic force of the elastic piece in addition to the torque limiter function. In this case, it is desirable to form three split grooves in both of the two outer rings arranged opposite to each other. The constant velocity joint in which the preload is applied to the ball B by the elastic piece can apply the preload without strictly managing the dimensional accuracy of each component. You can get a joint.

A longitudinal front view showing an embodiment of a constant velocity joint according to the present invention Sectional view along the line II-II in FIG.

Explanation of symbols

OR ₁ , OR ₂ outer ring J joint member B ball 4 annular space 5, 6 track groove 11 cage portion 12 pocket

Claims (5)

  Two outer rings having an annular space with one end opened and facing each other so that the opening ends of the annular space face each other, and a joint member having a cage portion inserted into the annular space of each outer ring at both ends Three track grooves extending in the axial direction are formed on at least one of the outer wall surface and the inner wall surface in the annular space of each outer ring at intervals of 120 ° in the circumferential direction, and roll along the track grooves. In the constant velocity joint in which a possible ball is held by each cage portion of the joint member, each of the outer rings is a synthetic resin molded product.   The constant velocity joint according to claim 1, wherein the joint member is a synthetic resin molded product.   The constant velocity joint according to claim 1, wherein the synthetic resin is made of a synthetic resin that can be injection-molded.   The constant velocity joint according to any one of claims 1 to 3, wherein the synthetic resin is a lubricating resin.   The constant velocity joint according to claim 1, wherein a preload is applied to the ball.

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