JP4515869B2 - Tripod type constant velocity joint - Google Patents

Description

  The present invention relates to a tripod 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.

The constant velocity joint described in Patent Document 1 is called a tripod type constant velocity joint, and is formed with three track grooves extending in the axial direction on the inner periphery of the outer ring at intervals of 120 ° in the circumferential direction. The tripod member built inside the outer ring is provided with three radial leg shafts that are inserted into the respective track grooves, and is a spherical roller that can roll along the track grooves outside each leg shaft. Are rotatably fitted and slidable in the axial direction, and rotational torque is transmitted between the outer ring and the tripod member via the spherical roller.
Japanese Patent Publication No. 3-1528

  By the way, in the tripod type constant velocity joint described in the above-mentioned Patent Document 1, since various parts of the outer ring, tripod member and spherical roller are made of metal such as steel, they are heavy but require heavy grease lubrication. 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.

  An object of the present invention is to provide a tripod type constant velocity joint that can eliminate the need for grease lubrication, is small in size, has a small operating sound, and is less subject to restrictions on use.

In order to solve the above problems, in the invention of this, the three track grooves extending in an inner periphery of the outer ring in the axial direction circumferentially formed at intervals of 120 °, was incorporated into the inside of the outer ring In the tripod type constant velocity joint, the tripod member is slidable in each track groove and provided with three protrusions for transmitting torque between the outer ring and the tripod member.
The projecting portion is curved in two directions, ie, a circumferential direction and an axial direction, with both sides of the projecting portion facing the side surface of the track groove as a spherical surface , and at least the projecting portion of the entire tripod member and the entire outer ring including the track groove. As a molded product of synthetic resin, a configuration that eliminates the need for grease lubrication was adopted.

In the tripod type constant velocity joint according to this invention, as a synthetic resin, by adopting an injection moldable synthetic resin, it is possible to facilitate the molding of various parts.

  In addition, by adopting a lubricating resin as the synthetic resin, a tripod constant velocity joint with smaller operation sound can be obtained.

  Here, by applying a preload between the contact portion between the track groove and the protruding portion, a tripod type constant velocity joint having no looseness in the circumferential direction and excellent in constant velocity can be obtained.

As described above , by using at least the protruding portion and the outer ring of the entire tripod member as a synthetic resin molded product, it is possible to obtain a constant velocity joint that is lightweight and has a small operation sound during torque transmission. Since grease lubrication can be dispensed with, the boot can be dispensed with, and a small tripod type 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.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in the figure, the tripod type constant velocity joint includes an outer ring 1 and a tripod member 11 incorporated inside the outer ring 1.

  The outer ring 1 has a configuration in which a first shaft 3 is provided at the closed end of the cup portion 2 whose one end is open, and three track grooves 4 extending in the axial direction from the opening end are provided on the inner periphery of the cup portion 2. Are formed at intervals of 120 ° in the circumferential direction. A pair of side surfaces 5 facing each other in the circumferential direction of each track groove 4 are flat surfaces parallel to each other.

  The tripod member 11 has a second shaft 12. The tripod member 11 is integrally provided with three projecting portions 13 that are inserted into the track grooves 4 of the outer ring 1.

  Each protrusion 13 is slidable in the track groove 4, and both sides facing the side surface 5 of the track groove 4 are formed as spherical surfaces 14, which are bent in two directions, the circumferential direction and the axial direction.

  When the rotational torque is input to one of the first shaft 3 and the second shaft 12, the protruding portion 13 engages one side 5 of the track groove 4 with one side surface 5 of the track groove 4, and the outer ring 1 at the engaging portion. Rotational torque is transmitted between the tripod member 11 and the tripod member 11.

  When the first shaft 3 and the second shaft 12 transmit torque at an angle, the projecting portion 13 slides along the track groove 4 in the axial direction of the outer ring 1. At this time, since the contact between the protruding portion 13 and the side surface 5 of the track groove 4 is a point contact, the sliding resistance is small, and the protruding portion 13 slides smoothly along the track groove 4.

  In the embodiment, both sides of the projecting portion 13 are the spherical surfaces 14, but the entire outer periphery or both sides of the projecting portion 13 may be a curved surface curved only in the circumferential direction.

  As shown in FIG. 1 and FIG. 2, an engagement groove 6 is formed on the inner periphery of the opening end portion of the cup portion 2 of the outer ring 1, and a retaining ring 7 that is partially cut off is attached to the engagement groove 6. It has been. The retaining ring 7 prevents the tripod member 11 from coming out of the open end of the cup portion 2.

  The entire tripod member 11 including the outer ring 1 and the protruding portion 13 is a synthetic resin molded product. An appropriate synthetic resin is selected depending on the use conditions of the tripod type 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 excellent in heat resistance and lubricity and relatively inexpensive, a constant velocity joint with excellent cost performance can be obtained.

  As described above, by using the outer ring 1 and the tripod member 11 as a synthetic resin molded product, a tripod constant velocity joint that is light in weight and has a low operating noise during torque transmission can be obtained, and grease lubrication can be performed. It can be unnecessary. Further, since it is not necessary to lubricate the grease, it is not necessary to attach a boot, and a small tripod type constant velocity joint having a simple structure with a small number of parts can be obtained. Moreover, PEEK is excellent in mechanical strength and lubricity even if it does not contain a reinforcing material or a lubricant, so that a highly functional tripod type constant velocity joint 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.

  When using a tripod type constant velocity joint for a medical device or a food manufacturing machine, 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 protruding portion 13, the tripod member 11, and the second shaft 12 are integrally formed of synthetic resin, but only the protruding portion 13 is formed of synthetic resin, and the tripod member 11 and the second shaft 12 are ceramics or steel, You may form with metals, such as stainless steel and an aluminum alloy. Alternatively, the protruding portion 13 and the tripod member 11 may be integrally formed with a synthetic resin, and the second shaft 12 made of a metal such as ceramics, steel, stainless steel, or aluminum alloy may be coupled with a coupling means such as a bolt.

  In addition, when the 2nd axis | shaft 12 is comparatively long, in order to prevent a torque loss, it is preferable to form the 2nd axis | shaft 12 with ceramics or a metal.

  In the outer ring 1, the cup portion 2 and the first shaft 3 are integrally formed of synthetic resin. However, the first shaft 3 is formed of ceramics, steel, stainless steel, aluminum alloy, or the like, and is coupled to the cup portion 2. You may make it do.

  As shown in the embodiment, by using the outer ring 1 as a synthetic resin molded product, preload can be applied to the contact portion between the protruding portion 13 and the side surface 5 of the track groove 4 by utilizing the elasticity of the outer ring 1. it can. Specifically, preload is applied to the contact portion between the projecting portion 13 and the both side surfaces 5 of the track groove 4 by making the size between the side surfaces 5 of the track groove 4 smaller than the size between the spherical surfaces 14 on both sides of the projecting portion 13. can do.

  Further, even if the outer ring is not a synthetic resin but ceramics, steel, stainless steel, aluminum alloy, or the like, the protrusion 13 is formed of a synthetic resin, and the protrusion 13 A preload can be applied to the contact portion of the side surface 5 of the track groove 4. Specifically, by making the dimension between the spherical surfaces 14 on both sides of the projecting portion 13 larger than the dimension between the both side surfaces 5 of the track groove 4, preload is applied to the contact portion between the projecting portion 13 and both side surfaces 5 of the track groove 4. can do.

  As described above, by applying a preload to the protruding portion 13, a tripod type constant velocity joint having no backlash in the circumferential direction and excellent in constant velocity can be obtained.

  Here, as shown in FIG. 1 and FIG. 2, when an axial separation portion 8 extending in the axial direction from the opening end of the cup portion 2 is formed on the outer peripheral wall portion of the track groove 4 formed in the cup portion 2, the cup Since the portion 2 can be elastically deformed in the radial direction, it is easy to apply a preload to the protruding portion 13, and it is not necessary to strictly manage the width dimension of the track groove 4, so that the outer ring 1 can be easily manufactured. Can be achieved.

  In the embodiment, the outer ring 1 and the tripod member 11 as a whole are molded products of synthetic resin, but only the protruding portion 13 of the tripod member 11 or only the outer ring 1 may be molded products of synthetic resin.

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

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 4 Track groove 5 Side surface 11 Tripod member 13 Protruding part 14 Spherical surface

Claims (4)

Three track grooves extending in the axial direction on the inner circumference of the outer ring are formed at intervals of 120 ° in the circumferential direction, and a tripod member built inside the outer ring is slidable in each track groove, In a tripod type constant velocity joint provided with three protrusions that transmit torque between the outer ring and the tripod member,
The projecting portion is curved in two directions, ie, a circumferential direction and an axial direction, with both sides of the projecting portion facing the side surface of the track groove as a spherical surface , and at least the projecting portion of the entire tripod member and the entire outer ring including the track groove. A tripod-type constant velocity joint characterized in that grease lubrication is unnecessary as a molded product of synthetic resin. The tripod constant velocity joint according to claim 1, wherein the synthetic resin is made of injection-moldable synthetic resin . The tripod constant velocity joint according to claim 1 or 2, wherein the synthetic resin is a lubricating resin . The tripod constant velocity joint according to any one of claims 1 to 3, wherein a preload is applied between contact portions of the track groove and the protruding portion .

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