JP4584089B2 - Constant velocity joint - Google Patents

Description

  The present invention relates to a constant velocity joint and an image forming apparatus that connect two shafts of a drive shaft and a driven shaft and transmit 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 axial center of the outer ring to form an annular space, and extends in the axial direction on 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 built in the annular space, and along the track groove in each pocket. A rolling ball is incorporated, and rotational torque is transmitted between the outer ring and the cage via the ball.
Japanese Patent Publication No. 52-34699

  By the way, in the conventionally known constant velocity joint, since each of the outer ring, the inner member, the cage and the ball is made of metal, grease lubrication is required, and the outer ring is opened by a boot which is attached by tightening the boot band. It is necessary to close the end to prevent leakage of grease.

  For this reason, when assembling and disassembling the constant velocity joint, it is necessary to install and remove boots in a complicated manner. The constant velocity joint is driven by the input side components that input power to the constant velocity joint and the output from the constant velocity joint. There has been a problem that it takes a lot of time to replace the damaged output side parts.

  In addition, although conventional metal constant velocity joints are high in strength, they are heavy, have a high operating noise, and there is a risk of grease leakage, so office machines, acoustic equipment, medical equipment, food manufacturing machines, homes, etc. There were problems with use in electrical appliances, and there were many restrictions on the location of use.

  The present invention provides a constant velocity joint that allows easy replacement of input side parts or output side parts and is easy to assemble and disassemble, and further eliminates the need for grease lubrication, and is lightweight, compact, and has low operating noise. It is a technical problem to provide a constant velocity joint that is less subject to use restrictions.

  In order to solve the above-described problems, in the present invention, there is an annular space having one end opened, and three track grooves extending in the axial direction on at least one of an outer wall surface and an inner wall surface of the annular space in the circumferential direction. An outer ring formed at an interval of 120 °, a cage incorporated in the annular space of the outer ring, and a pocket formed at a position corresponding to each of the track grooves, and incorporated in each pocket of the cage In a constant velocity joint composed of a ball that can roll along the track groove, the ball is dropped at the opening end of each pocket on the outer diameter side and the inner diameter side of each pocket. A configuration provided with a retaining means for preventing it was adopted.

  As the retaining means, it is possible to employ one comprising a plurality of protrusions formed at intervals in the circumferential direction on the inner surface of the opening end of the pocket.

  In the constant velocity joint, when a tapered surface having a large diameter end at the opening end of the outer wall surface and the inner wall surface in the annular space is provided at the opening end portion of each track groove, the cage is incorporated into the annular space of the outer ring. Sometimes, the ball is guided by the tapered surface, and when the outer ring and the cage are rotated relative to each other in the guided state, the ball is inserted into the track groove, and there may be a phase shift between the ball and the track groove. The constant velocity joint can be easily assembled.

  Further, in the constant velocity joint, by forming the outer ring as a synthetic resin molded product, the constant velocity joint can be made non-lubricated, and the operation sound during torque transmission can be reduced and reduced in weight.

In this case, by making the cage a molded product of synthetic resin, it is possible to further reduce the operation noise during torque transmission and further reduce the weight of the constant velocity joint.
When the cage is made of a synthetic resin molded product, the protruding portion becomes an undercut when the cage is molded. Therefore, if the protruding length of the protruding portion becomes longer than necessary, the protruding portion may be damaged when demolding after molding. If the ball is too short, the ball may fall off. For this reason, it is good to make the inscribed circle diameter of a protrusion part into the range of 70 to 99% of a ball diameter.

  In the constant velocity joint according to the present invention, the outer ring and the cage can be easily molded by using a synthetic resin that can be injection-molded as the synthetic resin. Further, by adopting the lubricating resin, it is possible to further improve the lubricity of the ball rolling surface, so that it is possible to obtain a constant velocity joint with a smaller operating noise.

  As described above, by providing a retaining means for preventing the ball from falling off at the opening end of the pocket formed in the cage, it is possible to prevent the ball from falling off when the cage is pulled out. It is very easy to assemble and disassemble.

  In addition, since the outer ring is made of a synthetic resin product, grease lubrication can be dispensed with, so there is no need to take measures to prevent grease leakage due to the installation of boots, light weight, low operating noise during torque transmission, and torque. A constant velocity joint with very little transmission loss can be obtained.

  Therefore, 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. Can be reduced, and downsizing and cost reduction can be achieved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show an embodiment of a constant velocity joint according to the present invention. As shown, the constant velocity joint includes an outer ring 1, a cage 10 and a ball 20.

  The outer ring 1 has a cup portion 2 that is open at one end, and a first shaft 3 is provided at the closed end of the cup portion 2. Further, a guide shaft 4 is provided on the central axis in the cup portion 2, an annular space 5 is formed between the guide shaft 4 and the cup portion 2, and the cup portion 2 that forms the outer wall surface of the annular space 5 is formed. Three track grooves 6 and 7 extending in the axial direction are provided on the outer peripheral surface of the guide shaft 4 that forms the inner peripheral surface and the inner wall surface of the annular space 5 at intervals of 120 ° in the circumferential direction.

  In the embodiment, the track grooves 6 and 7 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 cage 10 is incorporated in the annular space 5 of the outer ring 1, and a second shaft 11 is integrally provided at an end portion of the annular space 5 located on the opening end side.

  The cage 10 is formed with pockets 12 corresponding to the three track grooves 6 and 7 of the outer ring 1, and the balls 20 are incorporated in the pockets 12. Each of the balls 20 can roll along the track grooves 6 and 7.

As shown in FIGS. 1 and 2, a retaining means 13 for preventing the balls 20 from falling off is provided at the opening end of each pocket 12 on the cage outer diameter side and the cage inner diameter side.
The retaining means 13 includes a pair of protrusions 14 provided at positions facing the inner periphery of the pocket 12.

  The outer ring 1 and the cage 10 may be made of metal or may be made of a molded product of synthetic resin. When a synthetic resin molded product is used, grease lubrication is not required, and it is possible to achieve non-lubrication, a reduction in operation sound during torque transmission, and a reduction in weight. For this reason, in the embodiment, each of the outer ring 1 and the cage 10 is a synthetic resin molded product, but at least the outer ring 1 of the outer ring 1 and the cage 10 may be 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.

  Resin that can be injection-molded includes crystalline resin and non-crystalline resin, and either resin can be used. However, non-crystalline resin has low toughness and abrupt Since breakage occurs, 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). And wholly aromatic polyester resins, polyetheretherketone 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 excellent in heat resistance and lubricity and relatively inexpensive, a constant velocity joint with high 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 forming the outer ring 1 and the cage 10 as a molded product of synthetic resin, it is possible to obtain a constant velocity joint that is lightweight and has a low operating noise during torque transmission, and does not require grease lubrication. be able to.

For this reason, there are few restrictions on use, and it can be used for various kinds of equipment such as food production equipment.
Further, if the outer ring 1 and the cage 10 are made of sintered oil-impregnated metal, grease and boots are not required even if they are made of metal, so that there is no hindrance to replacement of constant velocity joint parts.

  The ball 20 may be a ball of bearing steel, stainless steel, ceramics, synthetic resin or the like, but it is preferable to use stainless steel, ceramics, or synthetic resin because there is no need to worry about rust even without lubrication. A synthetic resin is particularly preferable because it is lighter and quieter.

  When the constant velocity joint is used for a medical device or a food production device, it is preferable that the ball 20 is made of stainless steel or ceramic because environmental concerns are eliminated. In order to give a hygienic impression, it is preferable to use a white synthetic resin. POM is optimal because it is white and has high lubricity and can be made grease-free.

  When the cage 10 is formed of a synthetic resin that can be injection-molded, the protruding portion 14 of the retaining means 13 is undercut when the cage 10 is molded. Therefore, the length of the protruding portion 14 in the pocket radial direction is longer than necessary. In this case, the protruding portion 14 is damaged at the time of demolding after molding, and if it becomes too short, it is impossible to prevent the ball 20 from falling off.

  For this reason, the inscribed circle diameter d of the protrusion 14 is in the range of 70 to 99% of the ball diameter (ball diameter) D of the ball 20.

  In addition, the number of the protrusion parts 14 is arbitrary, and the cyclic | annular thing which continues in the circumferential direction may be sufficient. Further, the retaining means 13 is not limited to the protruding portion 14. For example, a retaining ring or an O-ring may be attached to the opening end of the pocket 12. Or you may make it cover the cage 10 with the cover in which the hole was formed according to the pocket 12.

  As described above, the retaining means 13 is provided in the pocket 12, and the outer ring 1 and the cage 10 are formed of synthetic resin so that grease lubrication is not required. The constant velocity joint can be assembled and disassembled by inserting and removing, and the balls 20 can be prevented from falling off during disassembly.

  Therefore, a constant velocity joint that can be easily assembled and disassembled can be obtained, and replacement of the input side component that inputs power to the constant velocity joint and the output side component that is rotationally driven by the output from the constant velocity joint are replaced. Can be easily performed.

  Here, as shown in FIGS. 1 and 3, in the annular space 5 at the opening end of the track groove 6 formed on the inner peripheral surface of the cup portion 2 and the track groove 7 formed on the outer peripheral surface of the guide shaft 4. When tapered surfaces 15 and 16 having large diameter ends at the open ends of the outer wall surface and the inner wall surface are provided, the ball 20 is guided by the tapered surfaces 15 and 16 when the cage 10 is assembled into the cup portion 2, and the guidance is performed. By rotating the outer ring 1 and the cage 10 relative to each other in this state, the ball 20 is inserted into the track grooves 6 and 7, and even when the track grooves 6 and 7 and the ball 20 are out of phase with each other. The constant velocity joint can be easily assembled.

  The tapered surfaces 15 and 16 may be tapered surfaces having an axial center on the central axis of the outer ring 1 as shown in FIG. 3, or axially on the pitch circle of the ball 20 as shown in FIG. It may be a tapered surface.

  As shown in FIG. 3, taper surfaces 15 and 16 having an axial center are formed on the central axis of the outer ring 1, and a minute guide protrusion 17 is formed between adjacent taper surfaces 15 and 16, thereby providing directionality. The constant velocity joint can be assembled without considering the above.

  In the embodiment, the cage 10 and the second shaft 11 are integrally formed of synthetic resin. However, the second shaft 11 is formed of a metal such as ceramics, steel, stainless steel, or aluminum alloy, and the cage 10 is formed of synthetic resin. And may be coupled by a coupling means such as a bolt.

  In addition, when the 2nd axis | shaft 11 is longer than the full length of a constant velocity joint, in order to prevent a torque loss, it is preferable to form the 2nd axis | shaft 11 with ceramics or a metal.

  In this embodiment, a preload can be applied to the ball 20 by the elastic force of the outer ring 1. Specifically, preload can be applied to the ball 20 by making the inner diameter between the track groove 6 of the cup portion 2 and the track groove 7 of the guide shaft 4 slightly smaller than the outer diameter of the ball 20. As a result, the backlash in the circumferential direction of the constant velocity joint can be eliminated, and the constant velocity can be improved. Such a specification is possible because the outer ring 1 is made of synthetic resin.

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. Sectional view along line III-III in FIG. Sectional drawing which shows other embodiment of the constant velocity joint which concerns on this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 5 Annular space 6, 7 Track groove 10 Cage 12 Pocket 13 Retaining means 14 Protruding part 15, 16 Tapered surface 20 Ball

Claims (7)

An outer ring having an annular space with one end open, and three track grooves extending in the axial direction on at least one of an outer wall surface and an inner wall surface of the annular space formed at intervals of 120 ° in the circumferential direction;
A cage that is incorporated in the annular space of the outer ring, has a pocket formed at a position corresponding to each of the track grooves , and is provided with a second shaft at an end located on the open end side of the annular space ;
It consists of a ball that is built into each pocket of the cage and rolls along the track groove,
At the opening end of the cage outer diameter side and cage inner diameter side of each pocket in the cage is provided with a retaining means for preventing the balls from falling off in a state where the cage is separated from the outer ring ,
The outer ring and the cage are made of synthetic resin and do not require grease lubrication and boots;
A constant velocity joint characterized in that it can be coupled and separated only by axial movement of the cage with respect to the annular space of the outer ring . The constant velocity joint according to claim 1, wherein the retaining means comprises a plurality of protrusions formed at intervals in the circumferential direction of the pocket. The constant velocity joint according to claim 2, wherein an inscribed circle diameter of the protruding portion is 70 to 99% of a ball diameter. 4. The constant velocity joint according to claim 1 , wherein a tapered surface having a large-diameter end at an opening end of the outer wall surface and the inner wall surface in the annular space is provided at an opening end portion of each track groove. The constant velocity joint according to claim 1, wherein the outer ring and the cage are formed of a synthetic resin. The constant velocity joint according to claim 5, wherein the synthetic resin is made of a synthetic resin that can be injection-molded. The constant velocity joint according to claim 1 , wherein the synthetic resin is a lubricating resin.

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