JP2007292210A - Constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To extend the service life of a metal mold, while preventing a ball from falling off from pockets in assembling and disassembling work, in a constant velocity universal joint having a cage composed of a synthetic resin mold. <P>SOLUTION: Slipping-out preventive parts 13 and 13 having an inscribed circle diameter (d) smaller than a diameter D of the ball, are formed in an opening end part on the cage outer diameter side and the cage inner diameter side of the respective pockets 12. In the cage 10, an annular part 14 arranged with the respective pockets 12 is divided so that the respective pockets 12 are divided into two parts in the cage axis direction. Respective divided inner surfaces 12a and 12b of the respective pockets 12 are formed in a shape of having no hiding part when viewed from the cage axis direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

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 is 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 angular displacement and axial displacement.

  As the sliding type constant velocity joint, as shown in FIGS. 5 and 6, one having an outer ring 51, a cage 52, and three balls 53 is known. An annular space 55 is formed in the outer ring 51 by providing a guide shaft 54 on the inner axis. In the cage 52 incorporated in the annular space 55, pockets 56 for holding the balls 53 are formed at intervals of 120 ° in the circumferential direction. At least one of the outer wall surface and the inner wall surface of the annular space 55 is provided with three track grooves 57 and 58 extending in the axial direction at positions corresponding to the pockets 56 at intervals of 120 ° in the circumferential direction. . The balls 53 incorporated in the pockets 56 can roll along the track grooves 57, 58, and transmit rotational torque between the outer ring 51 and the cage 52 via the balls 53. It has become.

  In the constant velocity joint as shown in FIG. 5 and FIG. 6, when various parts are made of metal such as steel, the strength is high, but grease lubrication is necessary. Such a thing has characteristics, such as loud operation sound, and a use location is restrict | limited. For example, it is not suitable for equipment used under conditions where quietness and grease scattering are not allowed, such as food manufacturing equipment, medical equipment, office equipment, household appliances, and acoustic equipment.

  For this reason, various parts of the constant velocity joint are formed of synthetic resin, and by reducing the weight of the various parts, there is a case in which grease lubrication is unnecessary and operation noise is reduced (see Patent Document 1).

JP 2006-38204 A

However, in the constant velocity joint as shown in FIGS. 5 and 6, when the outer ring 51 and the cage 52 are separated when assembling and disassembling work for breakage, replacement of consumables, etc., the pocket 56 becomes the outer ring 51. When the ball 53 comes out of the box, the balls 53 fall off from the pockets 56 and fall into the cage 52, or fall from the cage 52, which causes a problem of poor workability.
Further, when the cage 52 or the like is formed by injection molding, it is better that the mold life is longer in order to reduce the manufacturing cost.

  SUMMARY OF THE INVENTION An object of the present invention is to increase the life of a mold while preventing a ball from dropping out of a pocket during assembly and disassembly work in a constant velocity joint whose cage is formed of a synthetic resin.

  In order to achieve the above object, the present invention has 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 the outer ring, 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. A ball that can roll along a track groove, and the cage is a constant velocity joint made of a synthetic resin molded product. Forming a retaining portion smaller than the diameter of the ball, and dividing the annular portion in which each pocket is arranged in the cage so that each pocket is divided into two in the cage axis direction. The split inner surface, is obtained by employing the structure that was shaped portion without hidden when viewed from the cage axis.

Specifically, by adopting a configuration in which a retaining portion having an inscribed circle diameter smaller than the diameter of the ball is formed at the opening end of each pocket on the cage outer diameter side and cage inner diameter side, Do not fall out of each pocket unless pressed. Therefore, the constant velocity joint provided with the cage can prevent the ball from dropping out of the pocket during assembly and disassembly operations, and as a result, these operations can be easily performed.
Here, considering that each pocket is formed by a core pin inserted in the cage radial direction into the cage cavity, the retaining portion is undercut because its inscribed circle diameter is smaller than the diameter of the ball. . As a result, the core pin is forcibly removed, so that the mold is easily consumed.
Therefore, a mold that allows each pocket to be released in the cage axis direction by adopting a configuration in which the annular portion in which each pocket is arranged in the cage is divided so that each pocket is divided into two in the cage axis direction. Can be formed.
Further, by adopting a configuration in which each divided inner surface of each pocket has a shape that does not hide when viewed from the cage axis direction, in other words, each of the parts including the retaining portion when releasing in the cage axis direction. By preventing the undercuts from being formed on the respective divided inner surfaces of the pockets, it is possible to form the retaining portions without forcibly removing them.
Therefore, according to the above configuration, in the constant velocity joint whose cage is made of a synthetic resin molded product, the life of the mold can be extended while preventing the balls from falling off the pockets during assembly and disassembly operations.

  The inscribed circle diameter in the retaining portion is preferably 70 to 99% of the diameter of the ball. When the inscribed circle diameter is less than 70% of the diameter of the ball, it becomes too small as necessary and it becomes difficult to put the ball in the pocket. Further, if the inscribed circle diameter exceeds 99% of the diameter of the ball, the effect of preventing the ball from being pulled out may not be obtained due to a manufacturing error.

  As described above, according to the present invention, by adopting the above configuration, in the constant velocity joint in which the cage is formed of a synthetic resin molded product, the ball is prevented from dropping from the pocket during assembly and disassembly work, and the cage molding die It is possible to extend the service life.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
1 to 3 show the overall structure of a constant velocity joint according to an embodiment of the present invention. As illustrated, the constant velocity joint according to the embodiment 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 integrally 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. Although the track grooves 6 and 7 are formed on the outer wall surface and the inner wall surface of the annular space 5, respectively, 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 cage 10 located on the opening end side of the annular space 5.

  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.

  The pocket 12 is generally a cylindrical hole when viewed as a whole, and is symmetric with respect to a plane (corresponding to a cut surface taken along line II-II in FIG. 1) that includes the pocket central axis and is orthogonal to the cage axis direction. Is formed.

  At the opening end on the cage outer diameter side and the opening end on the cage inner diameter side of the pocket 12, a claw-shaped retaining portion 13 that protrudes toward the pocket inner diameter side is formed over the entire circumference.

  In this embodiment, the inscribed circle diameter d of the retaining portion 13 is an inner diameter at both open ends of the pocket 12 as shown in FIG. 3 and is smaller than the diameter D of the ball 20.

  Even if the ball 20 is about to fall out of the pocket 12, both the inner and outer diameters are prevented by the both retaining portions 13. Therefore, the constant velocity joint provided with the cage 10 can be easily assembled and disassembled.

  Note that the form of the stoppers 13 can be changed as appropriate. For example, it can also be made to protrude in a part of the circumferential direction of each opening end of the pocket 12. As shown in FIG. 4 when the pocket 12 of another example is viewed from the outer diameter side of the cage 10, the pocket 12 is formed to be opposed to the opening end of the pocket 12 on the outer diameter side of the cage 12 at intervals in the circumferential direction. A pair of protrusions 13a and 13a is formed, and a pair of protrusions 13 are formed at the opening end of the pocket 12 on the inner diameter side of the cage with a phase difference of 90 ° from the pair of protrusions 13a and 13a. The retaining portion 13 composed of the portions 13b and 13b can be formed. In this example, the inscribed circle diameter d of the retaining portion 13 is the diameter of the inscribed circle passing through the innermost point in the pocket radial direction of the pair of projecting portions 13a and 13a.

  The inscribed circle diameter d is preferably 70 to 99% of the diameter D of the ball 20. When the inscribed circle diameter d is less than 70% of the diameter of the ball, it becomes too small as necessary, making it difficult to put the ball 20 into the pocket 12. On the other hand, if the inscribed circle diameter d exceeds 99% of the diameter D of the ball 20, the effect of preventing the ball 20 from being detached may not be obtained due to a manufacturing error.

  The annular portion 14 in which the pockets 12 are arranged in the cage 10 includes a plane that is perpendicular to the cage axis direction and includes a pocket central axis of each pocket 12 (corresponding to a cut surface along line II-II in FIG. 1). Is divided).

  Each of the divided pieces 14a and 14b is made of a synthetic resin molded product. Specifically, each of the divided pieces 14a and 14b is formed by injection molding using a mold that is released in the cage axis direction.

  The split piece 14b is provided integrally with the second shaft 11, and the cage 10 is formed by joining the split faces of the split pieces 14a and 14b. For this joining, adhesion, welding, or the like can be used.

  Each pocket 12 is bisected in the cage axial direction because of its symmetrical shape with respect to the dividing surface of the annular portion 14. For this reason, one side of each division | segmentation inner surface 12a, 12b of each pocket 12 is formed in each division piece 14a, 14b of the annular part 14. As shown in FIG.

  FIG. 2 shows a state where the split end of the split piece 14a is viewed from the cage axis direction. Each divided inner surface 12a of each pocket 12 has a shape that does not hide when viewed from the cage axis direction including the retaining portion 13. That is, when the mold is released in the cage axis direction, each divided inner surface 12a of each pocket 12 including the retaining portion 13 has no undercut. Therefore, half of the retaining portion 13 is formed on each divided inner surface 12a of each pocket 12 without forcibly removing it.

  Here, since each pocket 12 has a symmetrical shape with respect to the dividing surface of the annular portion 14, when the divided piece 14 b of the annular portion 14 is injection-molded, the remainder of the retaining portion 13 remains on each divided inner surface 12 b of each pocket 12. Half is formed without forcing. Therefore, the constant velocity joint according to this embodiment can form both the retaining portions 13 in each pocket 12 without forcibly removing it, and can extend the life of the mold.

  In order to avoid grease lubrication, the outer ring 1 is made of a synthetic resin molded product in favor of weight reduction, but may be made of metal.

  What is necessary is just to select an appropriate thing for the said synthetic resin according to the use conditions of a constant velocity joint. For example, the synthetic resin may be either a thermoplastic resin or a thermosetting resin, and may be either a crystalline resin or an amorphous resin. Note that since the non-crystalline resin has a relatively low toughness, the crystalline resin is more preferable in that abrupt destruction can be avoided.

  Preferred synthetic resins include synthetic resins having excellent lubrication characteristics, such as polyacetal resin (POM), nylon resin, injection-moldable fluororesins such as PFA, FEP, and ETFE, injection-moldable polyimide resins, and polyphenylene sulfide resins ( PPS), wholly aromatic polyester resin, polyetheretherketone resin (PEEK), polyamideimide resin and the like.

  Each of the above resins may be a single or polymer alloy. Or the polymer alloy which mix | blended the said resin with resin with low lubrication characteristics other than the above may be sufficient.

  Moreover, even if it is resin with a low lubrication characteristic, if lubrication performance is improved by adding a solid lubricant and lubricating oil, it can be used. Examples of the solid lubricant include polytetrafluoroethylene, graphite, and molybdenum disulfide.

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

  The most suitable materials for molding the cage 10 and the like 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 excellent in cost effectiveness can be obtained by using these. Moreover, PEEK is excellent in mechanical strength and lubricity even if a reinforcing material and a lubricant are not blended. Therefore, when this is used, a high-performance constant velocity joint can be obtained.

  As described above, when the outer ring 1 and the cage 10 are formed of a synthetic resin, a constant velocity joint that is lightweight and has low operation sound can be obtained. As a result, grease lubrication can be eliminated. For this reason, the constant velocity joint which concerns on this embodiment is hard to receive the restriction | limiting of a use location, and can be used for various apparatuses.

  Balls 20 such as bearing steel, stainless steel, ceramics, and synthetic resins can be used as balls 20. However, the use of stainless steel, ceramics, and synthetic resins is preferable in that no rust problem occurs even without lubrication. If it is a synthetic resin, it is preferable at the point by which weight reduction and silence are implement | achieved.

  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. Moreover, in order to give a hygienic impression, when using a synthetic resin, a white thing is preferable. POM is suitable in that it is white, has high lubricity, and can be made grease-free.

  As described above, since the retaining portion 13 is provided in the pocket 12, the ball 20 is prevented from falling out of the pocket 12, so that the constant velocity joint is assembled by inserting / removing the cage 10 into / from the annular space 5 of the outer ring 1. In addition, the disassembling work can be easily performed.

  In particular, in this embodiment, at least the outer ring 1 and the cage 10 are made of a synthetic resin, and the weight is positively reduced. By eliminating the need for grease lubrication, no boots or the like are required, and the annular space 5 in the outer ring 1 is eliminated. Since the cage 10 can be directly inserted / removed with respect to the above, the constant velocity joint can be assembled and disassembled quickly in combination with the above-described retaining. As a result, it is possible to easily replace the input side component that inputs power to the constant velocity joint or the output side component that is rotationally driven by the output from the constant velocity joint. For this reason, the constant velocity joint according to this embodiment is often disassembled and assembled at the installation site, and is suitable for office equipment that takes time to take out when the ball falls into the equipment.

  In this embodiment, as shown in FIG. 1, an annular space is formed 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. Are provided with tapered surfaces 15 and 16 having large diameter ends at open ends of the outer wall surface and the inner wall surface.

  The tapered surfaces 15 and 16 guide the ball 20 toward the opening ends of the track grooves 6 and 7 when the cage 10 is assembled into the cup portion 2. Therefore, the ball 20 is inserted into the track grooves 6 and 7 by relatively rotating the outer ring 1 and the cage 10 in a state where the ball 20 is guided by the tapered surfaces 15 and 16. Therefore, in this embodiment, the constant velocity joint can be easily assembled even when the track grooves 6 and 7 and the ball 20 are out of phase with each other.

  The tapered surfaces 15 and 16 can be, for example, a tapered surface having an axial center on the central axis of the outer ring 1 or a tapered surface having an axial center on the pitch circle of the ball 20. Guide protrusions can also be formed between adjacent tapered surfaces.

  In this 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 is formed of synthetic resin. You may couple | bond with 10 and coupling | bonding means, such as a volt | bolt.

  In the outer ring 1, the cup portion 2 and the guide shaft 4 are integrally formed of synthetic resin. However, the guide shaft 4 is formed of ceramics, steel, stainless steel, aluminum alloy or the like so as to be coupled to the cup portion 2. It may be.

  Further, in this embodiment, by making the outer ring 1 a synthetic resin molded product, it is possible to apply a preload to the ball 20 using the elasticity of the outer ring 1. Specifically, the ball 20 is preloaded by making the inner diameter between the track groove 6 formed on the inner periphery of the cup portion 2 and the track groove 7 formed on the outer periphery of the guide shaft 4 smaller than the ball diameter of the ball 20. Can be granted. As a result, the constant velocity of the constant velocity joint can be improved. Such a specification is possible because the outer ring 1 is made of synthetic resin.

Vertical section of constant velocity joint according to an embodiment Sectional view taken along line II-II in FIG. The top view which looked at the pocket of FIG. 1 from the cage outer diameter side FIG. 1 is a plan view of another example of the pocket of FIG. 1 viewed from the cage outer diameter side. Longitudinal sectional view of conventional constant velocity joint Sectional view taken along line VI-VI in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Cup part 4 Guide shaft 5 Annular space 6, 7 Track groove 10 Cage 12 Pockets 12a, 12b Divided inner surface 13 Retaining parts 13a, 13b Protruding part 14 Annular parts 14a, 14b Divided piece 20 Ball

Claims (2)

An outer ring having an annular space with one end open, and three track grooves extending axially on at least one of an outer wall surface and an inner wall surface of the annular space at intervals of 120 ° in the circumferential direction; A cage in which a pocket is formed at a position corresponding to each of the track grooves, and a ball which is incorporated in each pocket of the cage and rolls along the track groove. In the constant velocity joint that the cage is made of a molded product of synthetic resin,
At the opening end of each pocket on the cage outer diameter side and the cage inner diameter side, a retaining portion having an inscribed circle diameter smaller than the diameter of the ball is formed,
The annular portion in which each pocket is arranged in the cage is divided so that each pocket is divided into two in the cage axis direction,
A constant velocity joint characterized in that each divided inner surface of each pocket has a shape that does not hide when viewed from the cage axis direction.   The constant velocity joint according to claim 1, wherein an inscribed circle diameter in the retaining portion is 70 to 99% of a diameter of the ball.

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