JP5006232B2 - Constant velocity joint - Google Patents

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 angular displacement and axial displacement.

  As the sliding type constant velocity joint, as shown in FIG. 5, one having an outer ring 51, a cage 52, and three balls 53 is known. The outer ring 51 has a cup portion 54 that is open at one end, and a first shaft 55 is provided at the closed end of the cup portion 54. An annular space 57 is formed in the outer ring 51 by providing a guide shaft 56 on the inner central axis. In the cage 52 incorporated in the annular space 57, pockets 58 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 57 is provided with three track grooves 59a, 59b extending in the axial direction at positions corresponding to the pockets 58 at intervals of 120 ° in the circumferential direction. . The balls 53 incorporated in the pockets 58 can roll along the track grooves 59a and 59b, and the rotational torque is transmitted between the outer ring 51 and the cage 52 via the balls 53. It has become. The first shaft 55 is used for coupling with a drive shaft or a driven shaft. The cage 52 is also provided with a second shaft for the same purpose.

In the constant velocity joint as shown in FIG. 5, when various parts are made of metal such as steel, the strength is high but grease lubrication is required. 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 made of synthetic resin, and various parts are reduced in weight, and at the same time, grease lubrication is not required, and operation noise is reduced (see Patent Document 1).

In the constant velocity joint described in the above-mentioned Patent Document 1, when the outer ring and the first shaft are formed separately, a gate for injection molding the outer ring is disposed on the outer diameter surface of the outer ring or the bottom of the outer surface of the outer ring. Alternatively, when the outer ring and the first shaft are integrally formed, the gate is arranged at the tip of the first shaft or the outer peripheral surface of the first shaft.
The gate is arranged in the above part because the outer wall surface of the annular space is formed on the inner peripheral surface of the outer ring, the inner wall surface of the annular space is formed on the outer peripheral surface of the guide shaft, and the inner and outer wall surfaces forming the annular space This is because the track groove is disposed on the surface. That is, the track groove is a portion that requires high molding accuracy, and it is not preferable to arrange a gate on the inner peripheral surface of the outer ring or the outer peripheral surface of the guide shaft where such a track groove is formed. For this reason, the gate is arrange | positioned in said part of the outer ring | wheel or 1st axis | shaft which does not affect the accuracy ensuring and function of a track groove.

JP 2006-38204 A

However, if there is a gate on the outer peripheral surface of the outer ring or the outer peripheral surface of the first shaft as in the constant velocity joint described in Patent Document 1, the synthetic resin is filled from the direction intersecting the central axis of the outer ring. Therefore, the filling balance to each track groove extending in the cavity becomes non-uniform. For this reason, the constant velocity joint of Patent Document 1 described above has variations in molding accuracy between the track grooves, and it is difficult to obtain very high constant velocity accuracy.
In addition, the first shaft has a hollow portion extending over the entire length on the central shaft to prevent sink marks, and the gate is eccentrically arranged at the tip of the first shaft, so that the filling balance cannot be made uniform. .

  In view of the above circumstances, an object of the present invention is to reduce variations in molding accuracy between the track grooves formed on the outer ring while reducing the weight of the outer ring of the constant velocity joint as an injection molded product of synthetic resin. It is in.

  In order to achieve the above object, the present invention has an annular space having an opening at one end, 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. An outer ring formed at an interval of the outer ring, a cage that is incorporated in the annular space of the outer ring, and is provided with a second shaft at an end located on the opening end side of the outer ring, and is held by the cage and is A ball that can roll along the track groove formed in the outer ring, and a guide shaft on which an inner wall surface of the annular space is formed is provided on a central axis of the outer ring, and the outer ring and the guide It is assumed that the constant velocity joint is integrally formed with the shaft by synthetic resin injection molding. This is to reduce the weight of the outer ring of the constant velocity joint as an injection molded product of synthetic resin.

In the present invention, based on the above premise, the gate of the outer ring is disposed on the central axis at one axial end of the outer ring, and the outer ring is rotationally symmetrical at 120 ° intervals in the circumferential direction around the central axis. The configuration is characterized by a shape (rotational symmetry).
If the gate is arranged on the central axis at one axial end of the outer ring, the synthetic resin can be filled in the axial direction from the central axis.
Further, if the outer ring (including the integrally formed guide shaft) has the rotational symmetry corresponding to the arrangement interval of the three track grooves, the composition is filled in the axial direction from the central axis of the outer ring. The resin spreads in the same way toward each track groove, and molding shrinkage of the filled synthetic resin also occurs in each track groove in the same way, that is, variation in molding accuracy is difficult to occur between the track grooves formed in the outer ring. Become.
Therefore, according to the present invention, it is possible to reduce variations in molding accuracy between the track grooves formed in the outer ring while reducing the weight of the outer ring of the constant velocity joint as an injection molded product of synthetic resin.

By adopting a configuration in which the first shaft is integrally formed by injection molding at the closed end of the outer ring, it is possible to prevent a decrease in constant speed accuracy caused by a shift of the center axis between the outer ring and the first shaft, and further, at a constant speed. The joint becomes lighter.
If the configuration in which the gate is a pinpoint gate is adopted, a circular gate trace remains only at the center of the tip end of the guide shaft, so that the gate trace is inconspicuous in terms of the appearance of the outer ring. Also, the gate can be automatically cut when the mold is opened after injection molding.

  When the gate is the pinpoint gate, if the gate is adopted in a recess formed at one end in the axial direction of the outer ring, the gate mark does not protrude from the recess, The catch is prevented and the gate mark is less noticeable.

  One end of the outer ring in the axial direction may be either the closed end of the outer ring, the tip of the first shaft, or the tip of the guide shaft. In particular, if a configuration in which a gate is disposed at the tip of the guide shaft is employed, in the coupling between the first shaft and the drive shaft or the driven shaft, the drive shaft or the driven shaft is inserted into the first shaft. The insertion hole is desirable because it can be formed by injection molding. In addition, when a gate is arranged at the closed end of the outer ring or the tip of the first shaft, the molten resin filling the cup portion will overflow due to the molten resin once entering the tip of the guide shaft flowing backward at the tip of the guide shaft. Since the route is such that the molten resin that comes out is filled in the cup portion, a slight time difference occurs in the formation of the track groove in the cup portion. On the other hand, when the gate is arranged at the tip of the guide shaft, the wall of the molten resin channel is formed by the insertion hole of the first shaft, so that the molten resin is quickly filled into the cup portion. For this reason, it is advantageous in terms of molding accuracy of the track groove of the cup portion to arrange the gate at the tip of the guide shaft. In addition, the tip of the guide shaft can be concealed by the cage, and gate traces are less noticeable.

  By adopting a configuration in which 10 to 65 parts by volume of the inorganic filler is blended with 100 parts by volume of the resin component as the base material in the synthetic resin, even if the guide shaft is formed solidly, Molding accuracy does not decrease due to sink marks.

By adopting a configuration in which the guide shaft has a hollow portion on the central axis excluding the tip, the molding shrinkage of the guide shaft is relieved by the amount of the hollow portion. Even if the synthetic resin does not contain more than the capacity portion, the molding accuracy of the guide shaft does not decrease due to sink marks.
If the shape having a hollow portion except for the tip end portion of the guide shaft is provided, the gate can be disposed on the central axis at the tip end of the guide shaft.
If the track grooves are formed on the outer peripheral surface of the guide shaft which has been reduced in molding shrinkage as described above, it is possible to prevent the molding accuracy of the track grooves from being lowered due to sink marks.

By adopting a configuration in which the cross-sectional shape of each track groove of the outer ring is a Gothic arch shape consisting of a pair of opposed arcuate curves, each track groove is compared with a perfect circular shape. As a result, the wear resistance of the track groove is increased and the product life is improved.
In addition, since the outer ring and the guide shaft are synthetic resin injection-molded bodies, it is possible to easily form a gothic arch shape of a track groove, which is difficult to manufacture with a metal.

  If the configuration in which the cage is formed by injection molding of synthetic resin is adopted, the constant velocity joint is further reduced in weight.

  Furthermore, if a configuration in which the cage and the second shaft are integrally formed by injection molding of a synthetic resin is adopted, it is possible to prevent a decrease in constant speed accuracy caused by the deviation of the central axis between the cage and the second shaft. Furthermore, the constant velocity joint becomes lighter.

  By adopting a configuration in which the synthetic resin is a lubricating resin, it is possible to obtain a constant velocity joint that can withstand long-term use without using a lubricant.

  As described above, according to the present invention, in the presupposed configuration, the outer ring has a rotationally symmetric shape at 120 ° intervals in the circumferential direction around the central axis, and the gate of the outer ring has the guide shaft. By adopting a configuration that is arranged on the center axis of the tip, the outer ring of the constant velocity joint is made as a synthetic resin injection molded product while reducing the weight, while varying the molding accuracy between the track grooves formed on the outer ring. It can be made difficult to occur. For this reason, very high uniform velocity accuracy can be obtained.

Hereinafter, a first embodiment of the present invention will be described with reference to the accompanying drawings.
1 and 2 show the entire structure of the constant velocity joint according to the first embodiment. As illustrated, the constant velocity joint according to the first 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. The first shaft 3 is formed with an insertion hole 3 a into which the driving shaft or the driven shaft is inserted along the central axis C of the outer ring 1. In the cup portion 2, a guide shaft 4 is provided integrally with the cup portion 2 on the central axis C. An annular space 5 is formed between the guide shaft 4 and the cup portion 2. Three track grooves 6, 7 extending in the axial direction are formed on the outer peripheral surface of the guide shaft 4 that forms the inner wall surface of the annular space 5 and the inner peripheral surface of the cup portion 2 that forms the outer wall surface of the annular space 5. They are provided at intervals of 120 ° in the circumferential direction.

  The cross-sectional shape of the three track grooves 6 and 7 provided in the outer ring 1 is a Gothic arch shape composed of a pair of opposed arcuate curves. By making the track grooves 6 and 7 into a Gothic arch shape, the ball 20 makes point contact at two locations on both sides of the inner surfaces of the track grooves 6 and 7. As a result, the variation in contact angle is reduced and the constant speed accuracy is improved. Furthermore, since the sliding resistance between the track grooves 6 and 7 and the ball 20 is reduced, the wear resistance of the track grooves is increased and the product life is improved.

  In the constant velocity universal joint of this embodiment, the cross-sectional shape of the track grooves 6 and 7 of the outer ring 1 is formed in a Gothic arch shape up to a portion Z beyond the contact point Y where the ball 20 is in angular contact as shown in FIG. In this case, the region between the portion Z exceeding the contact point Y and the shoulder X of the track grooves 6 and 7 is continuously formed in a straight line extending in the tangential direction at the portion Z exceeding the contact point Y. The

  The gothic arch portions 21 of the track grooves 6 and 7 are positioned on a line extending from the line segment connecting the contact point Y where the ball 20 having the radius r is in angular contact with the track grooves 6 and 7 and the ball center O toward the ball center. It has a track groove center O1 and a curvature radius R1 larger than the ball radius r. Usually, the ratio (contact rate) between the ball radius r and the radius of curvature R1 is 1.01-1.12, preferably 1.02-1.08.

  Thus, by making the track grooves 6 and 7 into a Gothic arch shape, the contact between the track grooves 6 and 7 and the ball 20 is an angular contact having a track contact angle α. Therefore, the formation angle β of the gothic arch portion 21 is larger than the track contact angle α and extends to the portion Z exceeding the contact point Y. Then, a relief portion 22 is formed between the portion Z beyond the contact point Y and the shoulder portion X of the track grooves 6 and 7.

  The escape portion 22 recedes from the radius of curvature of the gothic arch portion 21 and is formed in a straight line extending in the tangential direction at the portion Z beyond the contact point Y. The boundary portion with the Gothic arch portion 21, that is, the portion Z beyond the contact point Y, is smoothly connected while maintaining the continuity between the Gothic arch portion 21 and the relief portion 22. Therefore, the formation angle β of the gothic arch portion 21 is set smaller than the angle γ to the shoulder portion X of the track grooves 6 and 7. If the clearance between the shoulder portion X of the track grooves 6 and 7 and the ball 20 is increased at the escape portion 22, the shoulder portion X of the track grooves 6 and 7 may be damaged when the ball 20 rolls in the track grooves 6 and 7. Even if deformation or burrs are present, it is possible to suppress the deformation or burrs due to the scratches from interfering with the ball 20, and the contact ellipse between the ball 20 and the track grooves 6 and 7 when torque is applied. Therefore, it is possible to suppress the ball riding on the shoulder portion X of the track grooves 6 and 7.

  In the first embodiment, the track grooves 6 and 7 are formed on each of the inner wall surface and the outer wall surface of the annular space 5, but a track groove may be provided on one of the inner wall surface and the outer wall surface. .

  The outer ring 1 and the guide shaft 4 are integrally formed by injection molding of a synthetic resin in order to reduce the weight and eliminate the use of a lubricant. Since the outer ring 1 and the guide shaft 4 are synthetic resin injection-molded bodies, it is possible to easily form the Gothic arch shape of the track grooves 6 and 7 that are difficult to manufacture with metal.

  In FIG. 1, the position of the gate 8 of the outer ring 1 is indicated by an arrow. The gate 8 of the outer ring 1 is disposed on the central axis C at the tip of the guide shaft 4. This makes it possible to fill the synthetic resin in the axial direction from the center axis C.

  The gate 8 is a pinpoint gate. Pinpoint gates have very small gate traces because they are very small circular cross-sectional injection channels or throttle holes that leave little gate residue in the molded part. Also, the gate can be automatically cut when the mold is opened after injection molding. The gate shape is appropriately set according to the melt viscosity of the synthetic resin and the cavity volume of the injection mold, but the gate diameter is about 0.3 mm to 2 mm, and the gate land is about 0.8 mm to 1.2 mm. Is common. For this reason, the gate mark of the outer ring 1 remains small in a circular shape at the tip of the guide shaft 4 (the position of the gate 8 in FIG. 1), so that the outer ring 1 does not stand out in appearance. In FIG. 1, the illustration of the gate trace is omitted.

  The gate 8 is disposed in a recess 4 a formed at the tip of the guide shaft 4. For this reason, the gate trace of the outer ring 1 does not protrude from the recess 4 a of the guide shaft 4. Therefore, the dimension management of the guide shaft length can be easily performed. Further, the gate remainder of the outer ring 1 is prevented from being caught by the operator's hand during assembly, and the operator's safety can be ensured. Furthermore, the gate marks are less noticeable.

  Further, the tip of the guide shaft 4 on which the gate 8 is disposed is hidden in the cage 10 by assembly. For this reason, when assembled in a constant velocity joint, the gate trace is not visible on the outer ring 1.

  The outer ring 1 as a whole has a rotationally symmetric shape at 120 ° intervals in the circumferential direction around the central axis C. Since the outer ring 1 has rotational symmetry corresponding to the spacing between the track grooves 6 and 7, the synthetic resin filled in the direction of the central axis C is conceptually shown in FIG. It spreads in the same way toward the track grooves 6 and 7, and molding shrinkage of the filled synthetic resin also occurs in the track grooves 6 and 7 in the same manner. If the insertion hole 3a of the first shaft 3 is formed along the central axis C, the wall of the flow path of the molten resin is formed. Therefore, as shown in FIG. Is done promptly.

  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 outer ring 1 and the cage 10 are injection-moldable synthetic resin molded products. 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 fluororesin such as PFA, FEP, and ETFE, injection-moldable polyimide resin, polyphenylene sulfide resin ( PPS), wholly aromatic polyester resin, polyetheretherketone resin (PEEK), polyamideimide resin 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.

  Moreover, 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.

  As in the first embodiment, when the guide shaft 4 is a solid shaft, the synthetic resin is composed of 10 to 65 parts by volume of an inorganic filler, preferably 20 to 100 parts by volume of the resin component as the base material. 60 parts by volume may be blended. If the blending amount of the inorganic filler is less than 10 parts by volume, the effect of improving molding shrinkage due to sink marks is small, and if it exceeds 65 parts by volume, the injection moldability deteriorates and the flow in the cavity tends to be disturbed. The molding accuracy of the grooves 6 and 7 decreases. Further, if the blending amount of the inorganic filler is 20 parts by volume or more, the effect of improving the molding shrinkage is very high, and if it exceeds 60 parts by volume, the surface smoothness decreases depending on the type of the inorganic filler, Wear may occur.

  As the inorganic filler, inorganic fibers such as glass fiber, carbon fiber, various mineral fibers, as well as glass powder, carbon powder, zinc oxide powder, titanium oxide powder, calcium sulfate powder and the like can be used. .

The resin materials most suitable 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, it is possible to obtain a constant velocity joint with excellent cost performance.
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, the constant velocity joint according to the first embodiment can obtain a constant velocity joint that is light in weight and has a small operating sound during torque transmission by using the outer ring 1 as a synthetic resin molded product. it can.

  Further, the constant velocity joint according to the first embodiment is lighter in weight by using the outer ring 1 and the cage 10 as a synthetic resin molded product, and grease lubrication is unnecessary. Further, since it is not necessary to lubricate the grease, it is not necessary to attach the 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.

  The ball 20 can be a ball made of bearing steel, stainless steel, ceramics, synthetic resin, or the like. 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. By using the ball 20 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 first embodiment, the cage 10 and the second shaft 11 are integrally formed of a synthetic resin. However, the second shaft 11 is formed of a metal such as ceramics, steel, stainless steel, or aluminum alloy, and is formed of a synthetic resin. The cage 10 may be coupled with 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 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.

  As shown in the first embodiment, the cup portion 2 and the guide shaft 4 and the cage 10 and the second shaft 11 are integrally formed of synthetic resin, so that the constant velocity joint can be further reduced in weight.

  In the first embodiment, each of the outer ring 1 and the cage 10 is a synthetic resin molded product, but only the outer ring 1 may be a synthetic resin molded product.

As described above, the constant velocity joint according to the first embodiment having the above configuration is formed on the central axis C at the tip of the guide shaft 4 provided integrally with the cup portion 2 of the outer ring 1 when the outer ring 1 is injection-molded. Synthetic resin is filled in the direction of the central axis C from the arranged gate 8 and spreads in the same way toward the portions of the track grooves 6, 7. It happens in the same way in parts.
Therefore, in the constant velocity joint according to the first embodiment, the filling balance is uniform between the track grooves 6 and 7 formed in the outer ring 1, and variations in molding accuracy occur between the track grooves 6 and 7. As a result, very high constant velocity accuracy can be obtained.

  At this time, even if the cross-sectional shape of each of the track grooves 6 and 7 is a Gothic arch shape composed of a pair of opposing arcuate curves, the filling balance becomes uniform symmetrically on both sides of each track groove 6 and 7, and Variations in molding accuracy hardly occur on both sides of the grooves 6 and 7, and as a result, sliding is small and very high constant velocity accuracy can be obtained.

  In the first embodiment, the gate 8 is arranged at the tip of the guide shaft 4, but it can also be arranged at the tip of the first shaft 3 constituting the closed end of the outer ring 1.

  Since the constant velocity joint according to the first embodiment is excellent in constant velocity accuracy, it is used under the condition that even when the outer ring 1 or the like is molded with resin, the deflection due to the load during rotation transmission is within an allowable range. This is suitable for applications that require high constant speed accuracy, for example, when connecting the rotation shaft and the drive shaft of a photoreceptor provided in an image forming apparatus.

3 and 4 show a second embodiment of the constant velocity joint according to the present invention. As illustrated, the constant velocity joint according to the second embodiment is different from the first embodiment in that the guide shaft 4 is a hollow shaft.
Specifically, the guide shaft 4 according to the second embodiment has a hollow portion 4b on the central axis C excluding the tip portion. Since the guide shaft 4 has the hollow portion 4b, the molding shrinkage of the guide shaft 4 is relieved. Therefore, even if the synthetic resin does not contain 10 parts by volume or more of the inorganic filler as described above, the guide shaft 4 is molded. Accuracy does not decrease due to sink marks. Therefore, the constant velocity joint according to the second embodiment can prevent the forming accuracy of each track groove 6 formed on the outer peripheral surface of the guide shaft 4 from being lowered due to sink marks.

  The distal end portion of the guide shaft 4 is used for disposing the gate 8 inside the recess 4a as in the first embodiment. If the hollow portion 4b is within the range in which the ball can move on the track groove 6 when rotating at a constant speed, considering the axial direction, the hollow portion 4b has a portion where the molding accuracy is particularly required to obtain the constant speed accuracy. It is possible to prevent. The distal end portion of the guide shaft 4 only needs to be able to arrange the gate 8 in a range outside such a range.

Longitudinal front view of constant velocity joint according to the first embodiment Side view showing the outer ring of FIG. 1 from the opening end side Longitudinal front view of constant velocity joint according to second embodiment Sectional view taken along line IV-IV in FIG. Longitudinal front view of conventional example Cross-sectional view of a track groove according to the first embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer ring 2 Cup part 3 1st axis | shaft 4 Guide axis | shaft 4a Recessed part 4b Hollow part 5 Annular space 6 and 7 Track groove 10 Cage 12 Pocket 13 Retaining part 13a, 13b Protrusion part 20 Ball 21 Gothic arch part 22 Escape part

Claims (9)

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; Rolled along the cage that is incorporated in the annular space of the outer ring and has a second shaft at the end located on the opening end side of the outer ring, and the track groove that is held in the cage and formed in the outer ring. The outer ring has a cup portion that is open at one end and forms an outer wall surface of the annular space, and a guide shaft on which the inner wall surface of the annular space is formed is the center of the outer ring. In a constant velocity joint that is provided on a shaft and in which the outer ring and the guide shaft are integrally formed by injection molding of a synthetic resin, a first shaft is integrally formed by injection molding on the closed end of the outer ring. , the gate of the outer ring, the outer ring A on the center axis direction end are disposed at the distal end of the guide shaft, the outer ring has a shape rotationally symmetrical in the circumferential direction of 120 ° spacing of the central axis, to the first axis The insertion hole used for inserting the drive shaft or the driven shaft is formed along the central axis so as to form a wall of the flow path of the molten resin injected from the gate, etc. Fast joint. The constant velocity joint according to claim 1, wherein the gate is a pinpoint gate. Constant velocity joint according to claim 1 or 2 the gate is disposed in a recess formed in the distal end of the guide shaft. The constant velocity joint as described in any one of Claim 1 to 3 with which the said synthetic resin is mix | blended 10-65 volume parts of inorganic fillers with respect to 100 volume parts of resin components which are the base materials. It said guide shaft has a hollow portion along the said central axis, excluding the tip, one of the four claims 1 that the track groove is formed on an outer peripheral surface of the guide shaft 1 Constant velocity joint described in 1. The constant velocity joint according to any one of claims 1 to 5 , wherein a cross-sectional shape of each track groove of the outer ring is a Gothic arch shape including a pair of opposed arcuate curves. The constant velocity joint according to any one of claims 1 to 6 , wherein the cage is formed by injection molding of a synthetic resin. The constant velocity joint according to claim 7 , wherein the cage and the second shaft are integrally formed by injection molding of a synthetic resin. The constant velocity joint according to any one of claims 1 to 8 , wherein the synthetic resin is a lubricating resin.

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