JP4601538B2 - Fixed constant velocity joint - Google Patents

Description

  The present invention relates to a fixed type constant velocity joint that couples two axes of a drive shaft and a driven shaft and transmits the power of the drive shaft to the driven shaft.

  A constant velocity joint is known as a component that transmits 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 the constant velocity of the drive shaft and the driven shaft, and is therefore widely used in various industrial machines other than automobiles.

  As the constant velocity joint, there are known a fixed type constant velocity joint that allows only angular displacement and a sliding type constant velocity joint that allows angular displacement and axial displacement.

  Conventionally, a fixed constant velocity joint described in Patent Document 1 has been known. This fixed type constant velocity joint is provided with a plurality of arc-shaped ball rolling grooves extending in the axial direction on the spherical inner surface of the outer ring at equal intervals in the circumferential direction, and the outer ring ball on the outer spherical surface of the inner ring incorporated inside the outer ring. An arc-shaped ball rolling groove that faces the rolling groove in the radial direction is formed, and a ball for torque transmission is incorporated between the ball rolling groove of the inner ring and the ball rolling groove of the outer ring, and the ball is connected to the outer ring and the inner ring. It is held by a cage built in between.

Here, the center of curvature of the ball rolling groove of the outer ring and the center of curvature of the ball rolling groove of the inner ring are offset equidistantly to the left and right with respect to the joint center, and the outer ring and the inner ring take an operating angle to transmit torque. Sometimes, each of the balls is always placed on a bisector of the operating angle. For this reason, the outer ring and the inner ring transmit rotational torque while maintaining constant speed.
JP 2002-372066 A

  By the way, in the fixed type constant velocity joint described in Patent Document 1, since each component of the outer ring, inner ring, ball and cage is made of metal, it has high strength but is heavy and requires grease lubrication. There was a problem such as loud sound, 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 manufacturing equipment, food is contaminated by the leakage of grease, so it is necessary to take measures to prevent the leakage of grease by installing boots. There was a problem of increasing the size.

  An object of the present invention is to provide a fixed type constant velocity joint that can eliminate the need for grease lubrication, has a small operation sound, and is less restricted in use.

  In order to solve the above-described problems, in the present invention, a spherical shape of an inner ring incorporated in the inner side of the outer ring is provided with a plurality of arc-shaped ball rolling grooves extending in the axial direction at equal intervals in the spherical inner surface of the outer ring. An arc-shaped ball rolling groove that is radially opposite to the ball rolling groove of the outer ring is formed on the outer surface, and a torque transmitting ball incorporated between the ball rolling groove of the inner ring and the ball rolling groove of the outer ring In the fixed constant velocity joint held by the cage incorporated between the outer ring and the inner ring, a configuration in which each of the outer ring and the inner ring is a synthetic resin molded product is adopted.

  In the fixed type constant velocity joint having the above-described configuration, if the cage is a synthetic resin molded product, the constant velocity joint can be reduced in weight and a fixed type constant velocity joint with less operating noise can be formed. be able to.

  In the fixed constant velocity joint according to the present invention, when a synthetic resin that can be injection-molded is used as the synthetic resin, it is possible to facilitate the molding of various resin molded products.

  Further, by employing a lubricating resin as the synthetic resin, it is possible to obtain a constant velocity joint with a smaller operating sound.

  Here, by applying a preload to the ball by the elasticity of the outer ring and the inner ring made of synthetic resin, it is possible to obtain a fixed type constant velocity joint that is free from backlash in the circumferential direction and excellent in constant velocity.

  As described above, by forming the outer ring and the inner ring as a molded product of synthetic resin, it is possible to obtain a fixed type constant speed jet that is light in weight and has a small operation sound during torque transmission, and does not require grease lubrication. Therefore, it is not necessary to attach the boot, and a small fixed constant velocity joint having 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.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2 show a first embodiment of a fixed type constant velocity joint according to the present invention. As illustrated, the outer ring 1 has a closed end, and a first shaft 2 is provided at the closed end.

  The inner surface 3 of the outer ring 1 is spherical, and a plurality of arc-shaped ball rolling grooves 4 extending in the axial direction are formed in the spherical inner surface 3 at equal intervals in the circumferential direction.

  A spline hole 12 is provided in the inner ring 11 incorporated inside the outer ring 1, and a spline shaft portion 13 a provided at the end of the second shaft 13 is fitted into the spline hole 12.

  A retaining ring 14 is attached to the end of the second shaft 13. The retaining ring 14 is engaged with a shoulder 15 formed on the inner periphery of the end of the inner ring 11, and the second shaft 13 is prevented from being pulled out by the engagement.

  The outer surface 16 of the inner ring 11 has a spherical shape, and a plurality of arc-shaped ball rolling grooves 17 that are opposed to the ball rolling groove 4 of the outer ring 1 in the radial direction are provided on the spherical outer surface 16.

  A ball 21 that transmits torque between the outer ring 1 and the inner ring 11 is incorporated between the ball rolling groove 4 of the outer ring 1 and the ball rolling groove 17 of the inner ring 11.

  The ball 21 is fitted in a pocket 32 of a cage 31 incorporated between the outer ring 1 and the inner ring 11. The outer peripheral surface 33 of the cage 31 is a spherical shape along the spherical inner surface 3 of the outer ring 1, and the inner peripheral surface 34 of the cage 31 is a spherical shape along the spherical outer surface 16 of the inner ring 11.

The center of curvature O ₁ of the ball rolling groove 4 formed on the spherical inner surface 3 of the outer ring 1 and the center of curvature O ₂ of the ball rolling groove 17 formed on the spherical outer surface 16 of the inner ring 11 are relative to the joint center O _0. Are offset equidistant from side to side. For this reason, when the outer ring 1 and the inner ring 11 take the operating angle and transmit torque, the ball 21 is always disposed on the bisector of the operating angle, and constant-speed rotation is transmitted between the outer ring 1 and the inner ring 11. Is done.

  Each of the outer ring 1, the inner ring 11 and the cage 31 is a molded product of synthetic resin. As the synthetic resin, an appropriate resin is selected depending on the use conditions of the constant velocity joint, and any of a thermoplastic resin and a thermosetting resin may be used as long as the resin can be injection-molded.

  The resin that can be injection-molded includes a crystalline resin and an amorphous resin, and either resin may be used. However, the amorphous resin has low toughness, and when a torque exceeding an allowable amount is applied, it is abrupt. Since destruction occurs, it is preferable to use a crystalline resin.

  As preferred resins, synthetic resins having high lubricating properties, such as polyacetal resins (POM), nylon resins, fluororesins that can be injection-molded such as PFA, FEP, and ETFE, poniphenylene sulfide resins (PPS), wholly aromatic polyester resins, Examples thereof include polyetheretherketone resin (PEEK) and polyamideimide resin.

  Each of these resins may be used alone, or two or more of them may be mixed to form a polymer alloy.

  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, and 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 this invention are POM, nylon resin, PPS, PEEK. The nylon resin may be any of nylon 6, nylon 66, nylon 610, nylon 11, nylon 12, nylon 46, semi-aromatic nylon having an aromatic ring in the molecular chain, and the like. Since POM, nylon resin, and PPS are excellent in heat resistance and lubricity and relatively inexpensive, it is possible to obtain a fixed type constant velocity joint excellent in cost performance.

  As described above, the outer ring 1 and the inner ring 11 are formed of a synthetic resin, so that a fixed constant velocity joint that is light in weight and has a low operating noise during torque transmission can be obtained, and grease lubrication is unnecessary. It can be. Further, since it is not necessary to lubricate the grease, it is not necessary to attach a boot, and a fixed type constant velocity joint having a simple configuration with a small number of parts 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 highly functional fixed constant velocity joint can be obtained.

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

  When using a fixed constant velocity joint for medical equipment or food production equipment, it is preferable to use a white synthetic resin in order to give a hygienic impression. POM is optimal because it is white and has high lubricity and can be made grease-free.

  In the embodiment, the outer ring 1 and the first shaft 2 are integrally formed of synthetic resin. However, the outer ring 1 is formed of synthetic resin, and the first shaft 2 is formed of a metal such as ceramics, steel, stainless steel, or aluminum alloy. May be.

  Further, the second shaft 13 is separated from the inner ring 11, and the second shaft 13 is splined to the inner ring 11. However, even if the inner ring 11 and the second shaft 13 are integrally formed of synthetic resin. Good.

  As shown in the embodiment, by using the outer ring 1 and the inner ring 11 as a synthetic resin molded product, the preload can be applied to the contact portion with the ball 21 using the elasticity of the outer ring 1 and the inner ring 11. .

  Specifically, the inner diameter of the ball rolling groove 4 formed on the inner circumference of the outer ring 1 and the ball rolling groove 17 formed on the spherical outer surface 16 of the inner ring 11 is made smaller than the ball diameter of the ball 21. Can be preloaded. Thus, by applying a preload to the ball 21, it is possible to obtain a fixed type constant velocity joint that is free of backlash in the circumferential direction and has excellent constant velocity. Such a specification is possible because the outer ring 1 and the inner ring 11 are made of synthetic resin.

  3 and 4 show a second embodiment of a fixed type constant velocity joint according to the present invention. In the fixed type constant velocity joint shown in the second embodiment, three slits 5 extending in the axial direction from the open end of the outer ring 1 are provided at 120 ° in the circumferential direction between adjacent ball rolling grooves 4 of the outer ring 1. Unlike the fixed type constant velocity joint shown in the first embodiment in that an elastic piece 6 having a ball rolling groove 4 on the inner periphery is provided between adjacent slits 5. Yes.

  Since other configurations are the same as those in the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted.

  As described above, by forming the three slits 5 extending in the axial direction from the opening end of the outer ring 1 and providing the elastic pieces 6 between the adjacent slits 5, the rotational torque that can be allowed by the elastic modulus of the outer ring 1. When the above rotational torque is applied, each elastic piece 6 is elastically deformed radially outward, and torque transmission between the outer ring 1 and the inner ring 11 can be interrupted.

  For this reason, a function as a torque limiter can be added to the fixed type constant velocity joint, and an effect can be obtained in preventing the fixed type constant velocity joint from being damaged.

  Further, in the fixed type constant velocity joint in the second embodiment, the outer ring 1 is formed of a resin material having a high elastic modulus, or the outer ring 1 is made thick so that the elastic force of the elastic piece 6 is utilized. A preload can be applied to the ball 21, and by applying the preload, it is possible to obtain a fixed type constant velocity joint that is free from backlash in the rotation direction and excellent in constant velocity.

1 is a longitudinal front view showing a first embodiment of a fixed constant velocity joint according to the present invention. Sectional view along the line II-II in FIG. Longitudinal front view showing a second embodiment of the fixed constant velocity joint according to the present invention Sectional view along line IV-IV in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 3 Spherical inner surface 4 Ball rolling groove 11 Inner ring 16 Spherical outer surface 17 Ball rolling groove 21 Ball 31 Cage

Claims (4)

The inner surface of the outer ring having a closed end and having a first shaft provided at the closed end is spherical, and a plurality of arc-shaped ball rolling grooves extending in the axial direction are provided at equal intervals in the circumferential direction on the spherical inner surface; the inner ring is incorporated into the inside of the outer ring, facing in the first axis and provided with a second axis extending in the opposite direction, the outer surface of the inner ring with a spherical, ball rolling groove of the outer ring to the spherical outer surface of its radially An arc-shaped ball rolling groove is formed, and a torque transmitting ball built between the ball rolling groove of the inner ring and the ball rolling groove of the outer ring is held by a cage built between the outer ring and the inner ring. In fixed constant velocity joints,
The outer ring and the first shaft and the inner ring and the second shaft are integrated, and each of the outer ring including the first shaft, the inner ring including the second shaft, and the cage is an injection- molded product of crystalline synthetic resin. A fixed type constant velocity joint that eliminates the need for grease lubrication and boots and can be used for office machines, audio equipment, medical equipment, and household appliances . The fixed constant velocity joint according to claim 1 , wherein the synthetic resin is made of a lubricating resin . A slit extending in the axial direction from the opening end is formed in the outer ring, and a ball rolling groove is provided between adjacent slits on the inner periphery, and a rotational torque greater than the rotational torque allowed by the elastic modulus of the outer ring is loaded. The fixed type constant velocity joint according to claim 1 or 2, further comprising an elastic piece that elastically deforms radially outward to block torque transmission between the outer ring and the inner ring . The fixed constant velocity joint according to claim 3 , wherein a preload is applied between the ball rolling groove and a contact portion of the ball by using an elastic force of the elastic piece .

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