JP2005180641A - Constant velocity universal joint and method of manufacturing outer ring of constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of a compact and lightweight fixed constant velocity universal joint and its manufacturing method capable of reducing a range of an operating angle, properly used in a case of light load condition, and being manufactured at low cost. <P>SOLUTION: In this constant velocity universal joint which comprises the outer ring 12 provided with a plurality of track grooves 25 axially extended on a cylindrical inner peripheral face and a recessed spherical inner peripheral face 27, an inner ring 22 provided with a plurality of track grooves 26 axially extended on a projecting spherical outer peripheral face 28, torque transmitting balls 23 rotatably built in a ball raceway formed by the track grooves of the outer ring 21 and the track grooves 26 of the inner ring 22, and a cage 24 having pockets 39 for accommodating the torque transmitting balls 22, and having a projecting spherical outer peripheral face 29 and a recessed spherical inner peripheral face 30 engaged with the recessed spherical inner peripheral face 27 of the outer ring 21 and the projecting spherical outer peripheral face 28 of the inner ring 22, and wherein a center Ox of the projecting spherical outer peripheral face 29 and a center Oy the recessed spherical inner peripheral face 30 of the cage 24 are offset from an angular center Oo of the joint by equal distances oppositely from each other in the axial direction, the shape of a groove bottom in a longitudinal cross-section of the track grooves 25, 26 is a straight line in parallel with an axis. A cup part 21a of the outer ring 21 is molded by cold working, and a projection 32 for limiting the operating angle is mounted on a tip of a shaft 31. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rear wheel of a part-time four-wheel drive vehicle in which, for example, a constant velocity universal joint used for transmitting driving force to wheels in an automobile, for example, a front wheel is always driven and a rear wheel is driven as necessary. Related to fixed constant velocity universal joints, such as drive shafts, used in applications where the target vehicle travels for a very short time and in a limited time, and for which the operating angle and load torque are small Is.

Conventionally, the drive shaft for rear wheels of a part-time four-wheel drive vehicle that always drives the front wheels and drives the rear wheels as needed has light load conditions such as usage time and load torque. Compared to the shaft, a small constant velocity universal joint having a small load capacity is used. As the type, a fixed barfield type constant velocity universal joint is used on the wheel side, and a sliding double offset type or tripod type constant velocity universal joint is often used on the differential gear side. .
Japanese Patent Laid-Open No. 09-029380 (paragraph number 0009, FIGS. 1, 4, and 6) Japanese Unexamined Patent Publication No. 09-076026 (paragraph number 0009, FIG. 1, FIG. 4, FIG. 6) JP 2002-195286 A (paragraph numbers 0019 to 0023, FIGS. 1 and 3)

  There is a demand for part-time four-wheel drive vehicles for the purpose of ensuring running stability in extremely limited conditions such as snowy roads, even for small passenger cars whose needs have increased in recent years. Because of its low output, an unprecedented small and lightweight constant velocity universal joint is optimal for driving rear wheels. Further, as for the fixed type constant velocity universal joint used on the wheel side, the rear wheel without the steering mechanism does not require a large maximum operating angle of 40 ° or more unlike the front wheel.

  However, in the conventional method for manufacturing a constant velocity universal joint, it is very disadvantageous in terms of manufacturing cost to produce a small amount of a small constant velocity universal joint designed exclusively for this application. For this reason, the design of relatively small constant velocity universal joints that have already been mass-produced is often used, and as a result, large and heavy constant velocity universal joints with large load capacity for load conditions have been applied. . In particular, in the case of a Barfield type constant velocity universal joint used on the wheel side, high machining accuracy is achieved in the contour shape and relative position of the track groove and spherical surface formed in its component parts (outer ring, inner ring, cage). Is required.

FIG. 9 shows the structure of a bar field type constant velocity universal joint. In this constant velocity universal joint, a torque transmission ball 3 is incorporated between a track groove 5 of the outer ring 1 and a track groove 6 of the inner ring 2, and the torque transmission ball 3 is held by a cage 4. The outer ring 1 has a cup portion 1a and a shaft portion 1b extending in the axial direction from the bottom of the cup portion 1a. The cup portion 1 a has a concave spherical inner peripheral surface 7, and track grooves 5 extending in the axial direction are formed at a plurality of locations in the circumferential direction of the inner peripheral surface 7. The number of grooves is, for example, 6 or 8. An inlet chamfer 9 is formed at the opening edge of the cup portion 1a. The inner ring 2 is attached to a shaft 10, and a track groove 6 that forms a pair with the track groove 5 of the outer ring 1 is formed on the convex spherical outer peripheral surface 8. The track grooves 5 and 6 are curved with arc-shaped groove bottoms in the longitudinal section (FIG. 9). The cage 4 has a convex spherical outer peripheral surface 4 a and a concave spherical inner peripheral surface 4 b that are contact-guided by the inner peripheral surface 7 of the outer ring 1 and the outer peripheral surface 8 of the inner ring 2. The arc center O ₁ and the arc center O ₂ of the track grooves 6 of the inner ring 2 of the track grooves 5 of the outer ring 1, by the same distance offset to the right in the axial direction relative to the joint angle center O _0, the outer ring 1 and inner ring 2 When the operating angle takes an operating angle, the torque transmitting ball 3 is held at a position equally divided by the operating angle.

In the Barfield type constant velocity universal joint, the accuracy of the contour shape in the cross section of the track grooves 5 and 6 is good, the radius in the circular arc shape of the vertical section is precisely processed as designed, and O ₁ and O ₂ A small error in the offset amount is a factor that greatly affects the operability. If these machining precisions are poor, transmission loss and rotational torque will increase, causing vibration, noise, fuel consumption, etc. in the vehicle to deteriorate, and may cause serious defects such as excessive heat generation. Arise. Therefore, even when applying to light load conditions used in the above-mentioned limited circumstances, it is necessary to apply a manufacturing method with high processing accuracy such as finishing by cutting or grinding after heat treatment. The point was an impediment to reducing the manufacturing cost.

  As described above, the conventional constant velocity universal joint structure and manufacturing method are suitable for applications with a small operating angle range and light load conditions, such as a rear wheel drive shaft in a part-time four-wheel drive vehicle of a small passenger car. Therefore, it has been difficult to provide a small and lightweight fixed type constant velocity universal joint that can be manufactured at low cost.

  In order to solve this problem, the object of the present invention is a structure and manufacturing of a small and lightweight fixed type constant velocity universal joint that can be manufactured at a low cost and is suitable for applications with a small operating angle range and light load conditions. It is to provide a method.

  The fixed type constant velocity universal joint of the present invention extends in the axial direction to the outer ring 21 formed with a plurality of track grooves 25 and a concave spherical inner peripheral surface 27 extending in the axial direction on the cylindrical inner peripheral surface, and to the convex spherical outer peripheral surface 28. A torque transmission ball 23 rotatably incorporated in a ball raceway formed by an inner ring 22 having a plurality of track grooves 26, a track groove 25 of the outer ring 21 and a track groove 26 of the inner ring 22; And a cage 24 having a convex spherical outer peripheral surface 29 and a concave spherical inner peripheral surface 30 engaged with the concave spherical inner peripheral surface 27 of the outer ring 21 and the convex spherical outer peripheral surface 28 of the inner ring 22. In the fixed type constant velocity universal joint, the center Ox of the convex spherical outer peripheral surface 29 and the center Oy of the concave spherical inner peripheral surface 30 of the cage 24 are offset from the angular center Oo of the joint by an equal distance in the opposite directions in the axial direction. , Is characterized in that it has a parallel straight to the axis of the groove bottom shape in longitudinal section of the serial track grooves 25 and 26 (claim 1). As already described with reference to FIG. 9, in the bar field type constant velocity universal joint, the groove bottom shape in the longitudinal section of the outer and inner ring track grooves is an arcuate curve. The positional relation accuracy between the center of the arc of the groove bottom shape and the center of the concave spherical inner peripheral surface of the outer ring greatly affects the operability. On the other hand, in the present invention, since the groove bottom shape in the longitudinal section of the track groove 25 of the outer ring 21 is a straight line parallel to the axis, the position in the axial direction of the spherical center Ox of the concave spherical inner peripheral surface 27 of the outer ring 21. Has no effect on operability. This means that the finishing process is easy in the process of processing the concave spherical inner peripheral surface 27 of the outer ring 21 and leads to a reduction in manufacturing cost. Although the manufacturing process is different from that of the outer ring 21, the processing of the convex spherical outer peripheral surface 28 of the inner ring 22 has the same characteristics, and the finishing process is easy, leading to a reduction in manufacturing cost.

  Specifically, the outer ring 21 in the fixed type constant velocity universal joint of the present invention can be easily manufactured by cold press working such as ironing, as compared with the outer ring of the Barfield type constant velocity universal joint. The reason is that the shape of the cup portion 21a of the fixed type constant velocity universal joint of the present invention is such that the portion of the track groove 25 is expanded to the outer diameter side with respect to the tube material or the cylindrical material in the cold pressing process. Alternatively, conversely, the portion between the track grooves 25 can be easily obtained by reducing the diameter to the inner diameter side to give a small deformation (claims 5 and 6). In addition, a long drawn material having the same cross-sectional shape as the cup portion 21a may be formed by cold drawing and cut into an appropriate length (Claim 7).

  The invention according to claim 2 is the fixed type constant velocity universal joint according to claim 1, wherein the outer ring 21 is formed by cold working and then subjected to surface hardening treatment, and the necessary range is hardened by induction hardening. It is characterized by being formed by joining the shaft portion 21b. The cup portion 21a is manufactured by a cold forming method such as press working, and the shaft portion 21b having a different shape for each application vehicle is manufactured separately from the cup portion 21a, and the cup portion 21a and the shaft portion 21b are joined. By applying the manufacturing method for forming the outer ring 21 (Claim 8), the design of the cup portion 21a can be made common and produced together, which is advantageous in terms of cost.

  According to a third aspect of the present invention, in the fixed type constant velocity universal joint according to the first or second aspect, the tip of the shaft 31 coupled to the inner ring 22 has a part of the outer ring 21 when a certain operating angle θ is reached. This is characterized in that an interference projection 32 is provided. When the outer ring 21 and the shaft 31 reach a certain relative angle, the tip of the protrusion 32 interferes with a part of the outer ring 21, for example, the inner diameter portion of the annular body 33 provided on the inner periphery of the outer ring. The relative angle with respect to the shaft 31, that is, the operating angle θ is limited. Normally, the upper limit of the operating angle θ is set to about 25 ° to 30 ° in the application of a rear wheel drive shaft for a part-time four-wheel drive vehicle that always drives the front wheels and drives the rear wheels as needed. Functionally sufficient.

  In the manufacturing process prior to being attached to the vehicle, in the Barfield type constant velocity universal joint, the relative angle between the outer ring 21 and the shaft 31 is larger than the upper limit of the operating angle θ used in the vehicle, that is, outside the shaft 31. In many cases, it can be bent to an angle at which the diameter and the opening end of the outer ring 21 interfere. In this case, the maximum deformation that can be assumed occurs in the bellows-like portion or the bent deformation portion of the boot intended to seal the inside of the joint. As a result, the boots are unnecessarily large due to the design corresponding to a large operating angle that cannot be taken by a vehicle, and the amount of lubricant enclosed in the boots is large, so that it is difficult to reduce costs. On the other hand, as in the present invention, the protrusion 35 and the annular body 33 are provided and the operating angle θ is structurally limited, so that the boot 35 is designed to the minimum necessary size and the amount of lubricant is small. This makes it possible to reduce the cost.

  In addition, the fixed type constant velocity universal joint of the present invention is structured so that it can be assembled by a method in which the torque transmission balls 23 are assembled one by one after the cage 24 and the inner ring 22 are assembled in the cup portion 21a. If the relative angle between the outer ring 21 and the inner ring 22 becomes excessive later, there arises a problem that the torque transmitting ball 23 falls out of the pocket 39 of the cage 24. Therefore, in the manufacturing process, after the shaft 31 is inserted and fitted into the inner ring 22, means (32, 33) for limiting the operating angle θ is provided so that the relative angle between the outer ring 21 and the inner ring 22 does not become excessive. Is very convenient. By forming the protrusion 32 as a part of the shaft 31 and the annular body 33 as a part of the shaft portion 21b of the outer ring 21, an increase in manufacturing cost can be suppressed.

According to a fourth aspect of the present invention, in the fixed type constant velocity universal joint of the first, second or third aspect, the diameter of the torque transmission ball 23 is d, the diameter of the circle connecting the centers of the torque transmission balls 23 is PCD, and the concave of the outer ring 21 is. When the diameter of the spherical inner peripheral surface 27 is S ₁ , the diameter of the convex spherical outer peripheral surface 28 of the inner ring 22 is S ₂ , and the thickness of the track groove 25 in the cold working of the cup portion 21a of the outer ring 21 is t. The ratio d: PCD: S ₁ : S ₂ : t is 1.0: (2.6-3.3) :( 3.0-4.3) :( 2.3-3.7) :( 0 .22 to 0.42), and the number of torque transmitting balls 23 is five. In order to achieve both the required strength and durability as a constant velocity universal joint and the assemblability in the method of incorporating the torque transmission ball 23 after the cage 24 and the inner ring 22 are assembled in the cup portion 21a, the number of torque transmission balls 23 is five. It is set to pieces.

  When the ratio of each dimension and the number of torque transmission balls are out of the above ranges with d = 1.0 as a reference, the following typical problems or trends occur.

  If the PCD is larger than the upper limit ratio 3.3, the outer diameter of the cup portion 21a is increased, and the lightweight and compactness is lowered. A cup portion 21a that is lighter and more compact than that formed by warm or hot forging, which is a conventional manufacturing method, cannot be obtained.

  If the PCD is smaller than the lower limit ratio 2.6, the columnar portion between the adjacent pockets 39 of the cage 24 becomes thin, and the allowable transmission torque of the joint decreases due to the strength reduction of the cage 24.

When S ₁ is made larger than the upper limit ratio 4.3, the track groove 25 of the cup portion 21a becomes shallow and the ball 23 can easily ride on the shoulder of the groove, and the contact point between the track groove 25 and the ball 23 becomes the track groove 25. As a result, the strength of the cup portion 21a decreases, and the allowable transmission torque of the joint decreases. If S ₁ is made smaller than the lower limit ratio of 3.0, the convex spherical outer peripheral surface 29 and the concave spherical inner peripheral surface 30 of the cage 24 approach each other and the wall thickness decreases, so that the strength of the cage 24 decreases, Allowable transmission torque decreases.

If S ₂ is made larger than the upper limit ratio of 3.7, the convex spherical outer peripheral surface 29 and the concave spherical inner peripheral surface 30 of the cage 24 approach each other and the wall thickness becomes thin. Allowable transmission torque decreases. If S ₂ is made smaller than the lower limit ratio 2.3, the track groove 26 of the inner ring 22 becomes shallow, and the torque transmission ball 23 easily rides on the shoulder of the groove, and the contact point between the track groove 26 and the torque transmission ball 23 becomes the track. By dropping from the groove 26, the strength of the inner ring 22 is reduced and the allowable transmission torque of the joint is reduced.

  When t is made larger than the upper limit ratio 0.42, the weight of the cup portion 21a is increased, and the light weight and compactness are lowered. A cup portion 21a that is lighter and more compact than that formed by warm or hot forging, which is a conventional manufacturing method, cannot be obtained. When t is smaller than the lower limit ratio of 0.22, the strength of the cup portion 21a with respect to the load applied from the ball 23 to the track groove 25 due to the load torque of the joint decreases, and the allowable transmission torque of the joint decreases.

  When the number of the torque transmission balls 23 is increased, the columnar portion between the adjacent pockets 39 of the cage 24 cannot be formed, and the structure of the cage 24 is not established. On the contrary, if the number of torque transmission balls 23 is reduced, the contact load between the torque transmission balls 23 and the track grooves 25 and 26 with respect to the load torque of the joint increases. Transmission torque decreases. In addition, since the wear of the torque transmission ball 23 and the track grooves 25 and 26 becomes severe, the durability of the joint also decreases.

As described above, the dimension ratio of d, PCD, S ₁ , S ₂ , and t and the number of torque transmission balls are functions (allowable load torque, durability) and characteristics (light weight / compact) of the fixed type constant velocity universal joint of the present invention. Sex). The above-mentioned dimensional ratio is set for the purpose of the fixed constant velocity universal joint of the present invention exhibiting the optimum functions and characteristics for the application.

  According to the present invention, a small and lightweight fixed type that can be manufactured at a low cost and is suitable for applications with a small operating angle range and a light load condition, such as a rear wheel drive shaft in a part-time four-wheel drive vehicle of a small passenger car. A structure and manufacturing method of a constant velocity universal joint can be provided.

  The main point of the present invention is that, in applying cold pressing as a manufacturing method of the cup portion of the outer ring, the structure of the fixed type constant velocity universal joint that is most easy to mold the cup portion is selected and the manufacturing method is devised. It is. By comprehensively examining the application, structure, and manufacturing method of constant velocity universal joints, the manufacturing cost can be suppressed, but the advantage of cold pressing that restricts the shape that can be molded compared to the molding method by forging, It is possible to provide a manufacturing method that makes the most of it.

  An embodiment of the present invention will be described with reference to FIGS. The fixed type constant velocity universal joint according to this embodiment includes an outer ring 21, an inner ring 22, a torque transmission ball 23, and a cage 24 as main components. Reference numeral 35 denotes a boot.

  The outer ring 21 includes a cup portion 21a and a shaft portion 21b. The cup portion 21a is substantially cylindrical, and has a plurality of (here, five) track grooves 25 extending in the axial direction on the inner peripheral surface. The groove bottom shape in the longitudinal section (FIG. 1A) of the track groove 25 is a straight line parallel to the axis. A concave spherical inner peripheral surface 27 is formed in a portion between the track grooves 25. In manufacturing the cup portion 21a, after forming from a low carbon steel circular pipe material by cold press working, the concave spherical inner peripheral surface 27, the engagement groove 34 for mounting the boot 35, and the shaft portion 21b. After cutting a necessary portion such as a joint, and further performing a surface hardening treatment by carburizing and quenching, the concave spherical inner peripheral surface 27 is finished. The shape of the cup portion 21a is such that the portion of the track groove 25 is expanded toward the outer diameter side with respect to the circular pipe material, or conversely, the portion between the track grooves 25 is reduced in diameter toward the inner diameter side in cold pressing. Thus, it can be easily obtained by giving a small deformation. The shape accuracy and positional relationship accuracy required for the track grooves 25 can be sufficiently achieved by the above-described processing method, and does not require finishing after heat treatment. The shaft portion 21b is obtained by subjecting a raw material roughly formed by forging to a cutting process to obtain a necessary shape, and then performing a heat treatment. In this embodiment, the cup portion 21a and the shaft portion 21b are joined by providing an appropriate groove shape on the outer diameter surface of the engaging portion and welding as shown by reference numeral 38, and the above-mentioned carburization is performed. In the quenching process, the periphery of the joint portion of the cup portion 21a is subjected to a carbon-proof treatment.

  The inner ring 22 is coupled to the shaft 31 so that torque can be transmitted by a detent means represented by splines and serrations. The inner ring 22 has a convex spherical outer peripheral surface 28, and a track groove 26 corresponding to the track groove 25 of the outer ring 21 is formed on the outer peripheral surface. Again, the groove bottom shape in the longitudinal section of the track groove 26 (FIG. 1A) is a straight line parallel to the axis. The inner ring 22 is formed by subjecting a forging material to cutting or broaching, subjecting it to surface hardening treatment by carburizing and quenching, and then finishing the convex spherical outer peripheral surface 28. As with the cup portion 21a of the outer ring 21, the inner ring 22 can sufficiently achieve the shape accuracy and positional relationship accuracy required for the track groove 26 by subjecting the material formed by cold forging to the aforementioned processing. It does not require finishing after heat treatment.

  The track groove 25 of the outer ring 21 and the track groove 26 of the inner ring 22 form a pair, and a single torque transmission ball 23 is rotatably incorporated in each pair of track grooves. In this embodiment, there are five torque transmission balls 23, each held in a pocket 39 of the cage 24. The cage 24 has a convex spherical outer peripheral surface 29 and a concave spherical inner peripheral surface 30 that engage with the concave spherical inner peripheral surface 27 of the outer ring 21 and the convex spherical outer peripheral surface 28 of the inner ring 22. The centers Ox and Oy of the convex spherical outer peripheral surface 29 and the concave spherical inner peripheral surface 30 of the cage 24 are offset equidistantly from each other in the axial direction from the angular center Oo of the joint. The cage 24 is formed by cutting a forged material, subjecting it to surface hardening treatment by carburizing and quenching, and then finishing the convex spherical outer peripheral surface 29 and the concave spherical inner peripheral surface 30.

In the embodiment shown in FIGS. 1 and 2, the diameter of the torque transmission ball 23 is d, the diameter of the circle connecting the centers of the torque transmission balls 23 is PCD, and the diameter of the concave spherical inner peripheral surface 27 of the cup portion 21a is S _1. When the diameter of the convex spherical outer peripheral surface 28 of the inner ring 22 is S ₂ and the thickness of the track groove in the press molding of the cup portion 21a is t, the ratio d: PCD: S ₁ : S ₂ : t is 1.0: (2.6 to 3.3): (3.0 to 4.3): (2.3 to 3.7): (0.22 to 0.42) ing.

  A protrusion 32 for limiting the operating angle is provided at the tip of the shaft 31. As shown in FIG. 2, when the inner ring 22 and the shaft 31 reach a certain operating angle θ with respect to the outer ring 21, the tip of the protrusion 32 interferes with the annular body 33 provided on the inner periphery of the outer ring 21. Due to this, the operating angle is limited. Usually, in a use of a rear wheel drive shaft in a part-time four-wheel drive vehicle in which the front wheels are always driven and the rear wheels are driven as necessary, the upper limit of the operating angle θ is set to about 25 ° to 30 °. .

  The boot 35 is formed by an injection molding method using chloroprene rubber as a material. The boot 35 is fixed to the shaft 31 by the metal fixing bands 36 and 37, and the large diameter end to the cup portion 21a. The shape of the bellows-like portion located in the axial center of the boot 35 is designed according to the operating angle range of the constant velocity universal joint to be applied. In general, considering the durability of boots in constant velocity universal joints, the wider the operating angle range of the target constant velocity universal joint, the longer the shape of the bellows-like portion is in the axial direction and the greater the number of pleats There is a need. However, since the operating angle is limited by the above-described structure, the bellows-like portion of the boot 35 can be designed to the minimum necessary size. Further, since the internal volume of the boot 35 is small, the amount of lubricant filled in the boot 35 can be reduced.

  Next, the method for assembling the constant velocity universal joint of the illustrated embodiment will be described with reference to FIGS.

  First, as shown in FIG. 3, the rotational phases of the inner ring 22 and the cage 24 are matched, and the inner ring 22 is inserted into the cage 24 in the direction of the arrow in the axial direction as shown in FIG.

  Next, the inner ring 22 is rotated with respect to the cage 24 so that the convex spherical outer peripheral surface 28 of the inner ring 22 and the concave spherical inner peripheral surface 30 of the cage 24 are engaged, and the state shown in FIG. 4 is reached.

  As shown in FIG. 5, the rotation phases of the inner ring 22 and the cage 24 and the cup portion 21a are matched (FIG. 5B), and the inner ring 22 and the cage 24 are inserted in the direction of the arrow in the axial direction with respect to the cup portion 21a. (FIG. 5A).

The inner ring 22 and the cage 24 are rotated with respect to the cup portion 21a so that the convex spherical outer peripheral surface 29 of the cage 24 and the concave spherical inner peripheral surface 27 of the cup portion 21a are engaged, and the state shown in FIG. 6 is reached.
5) As shown in FIG. 7, the torque transmission balls 23 are placed one by one at a position where the inclination angles θ ₁ and θ ₂ of the inner ring 22 and the cage 24 with respect to the cup portion 21a are θ ₁ = 2 × θ ₂ (total 5 places) Insert.

  Thereafter, a lubricant (not shown) is sealed inside, the shaft 31 is inserted into the inner ring 22, and the boot 35 is fixed by the bands 36 and 37 as shown in FIG.

  As described above, the fixed type constant velocity universal joint shown in FIG. 1 which is an embodiment of the present invention provides a constant velocity universal joint that can be manufactured at a lower cost than a conventional barfield type constant velocity universal joint. Is possible.

  As another embodiment, instead of forming the cup portion 21a from a circular pipe material, a disk-shaped plate material is formed into a bottomed cylindrical material by drawing and the portion of the track groove 25 is formed in the outer diameter in the same manner as described above. The same shape may be obtained by expanding the diameter to the side, or conversely, by reducing the portion between the track grooves 25 to the inner diameter side and then cutting and molding the bottom.

  Moreover, FIG. 8 shows an embodiment in which a long drawn material having the same cross-sectional shape as the cup portion is formed by cold drawing and cut into an appropriate length to form the cup portion. The cross-sectional shape of the joint portion between the cup portion 21a and the shaft portion 21b is different from that of the embodiment shown in FIG.

  As yet another embodiment, after the cup portion is molded using the above-mentioned low carbon steel, instead of the method of carburizing and quenching, it is possible to subject the one formed by press molding using high carbon steel to induction hardening. Alternatively, other joining means such as laser welding or friction welding may be applied to the joining method with the shaft portion. In any case, it is possible to reduce the manufacturing cost intended by the structure of the fixed type constant velocity universal joint of the present invention.

a is a longitudinal cross-sectional view of the constant velocity universal joint which shows embodiment of this invention, b is a cross-sectional view. It is a longitudinal cross-sectional view which shows the state which the joint of Fig.1 (a) took the operating angle (theta). a is a longitudinal sectional view of the inner ring and the cage, and b is a side view. a is a longitudinal sectional view of the inner ring and cage assembled, and b is a side view. 4A is a longitudinal sectional view of the outer ring, and FIG. 4B is a side view. a is a longitudinal sectional view of an inner ring, a cage and an outer ring assembled together, and b is a side view. It is a longitudinal cross-sectional view which shows the point which incorporates a ball | bowl in the inner ring | wheel, the cage, and the outer ring | wheel of the state of FIG. a is a longitudinal sectional view of a constant velocity universal joint showing another embodiment, and b is a transverse sectional view. It is a longitudinal cross-sectional view of the constant velocity universal joint which shows the prior art.

Explanation of symbols

21 outer ring 21a cup portion 21b shaft portion 22 inner ring 23 torque transmission ball 24 cage 25 track groove 26 track groove 27 concave spherical inner peripheral surface of cup portion 21a 28 convex spherical outer peripheral surface of inner ring 22 convex spherical outer peripheral surface of cage 24 30 cage 24 concave spherical inner peripheral surface 31 shaft 32 protrusion 33 annular body 34 boot groove 35 boot 36 boot band 37 boot band 38 welded portion 39 pocket

Claims (8)

  A plurality of track grooves extending in the axial direction on the cylindrical inner peripheral surface and an outer ring having a concave spherical inner peripheral surface, an inner ring having a plurality of track grooves extending in the axial direction on the convex spherical outer peripheral surface, and a track groove of the outer ring, A torque transmission ball that is rotatably incorporated in a ball raceway formed by a track groove of the inner ring, a pocket that accommodates the torque transmission ball, and a concave spherical inner peripheral surface of the outer ring and a convex spherical outer peripheral surface of the inner ring; A cage having an engaging convex spherical outer peripheral surface and a concave spherical inner peripheral surface, and the center of the convex spherical outer peripheral surface and the center of the concave spherical inner peripheral surface of the cage are opposite to each other in the axial direction from the angular center of the joint. A fixed type constant velocity universal joint which is offset at an equal distance, wherein the groove bottom shape in the longitudinal section of the track groove is a straight line parallel to the axis.   2. The outer ring is constituted by joining a cup portion formed by cold working and then subjected to surface hardening treatment and a shaft portion obtained by hardening the necessary range by induction hardening. Fixed constant velocity universal joint.   3. The fixed type constant velocity universal joint according to claim 2, wherein a projection that interferes with a part of the outer ring when a certain operating angle is reached is provided at a tip of a shaft coupled to the inner ring. The diameter of the torque transmission ball is d, the diameter of the circle connecting the centers of the torque transmission balls is PCD, the diameter of the concave spherical inner peripheral surface of the outer ring is S ₁ , the diameter of the convex spherical outer peripheral surface of the inner ring is S ₂ , and the cup portion of the outer ring The ratio d: PCD: S ₁ : S ₂ : t is 1.0: (2.6 to 3.3) :( 3.0 To 4.3): (2.3 to 3.7): (0.22 to 0.42), and the number of torque transmitting balls is five. Item 2 or 3 fixed type constant velocity universal joint.   A plurality of track grooves extending in the axial direction on the cylindrical inner peripheral surface, an outer ring comprising a cup portion and a shaft portion formed with a concave spherical inner peripheral surface, and an inner ring formed with a plurality of track grooves extending in the axial direction on the convex spherical outer peripheral surface A torque transmission ball rotatably incorporated in a ball raceway formed by a track groove of the outer ring and a track groove of the inner ring, a pocket for accommodating the torque transmission ball, a concave spherical inner peripheral surface of the outer ring, and A cage having a convex spherical outer peripheral surface and a concave spherical inner peripheral surface that engage with the convex spherical outer peripheral surface of the inner ring, and the center of the convex spherical outer peripheral surface of the cage and the center of the concave spherical inner peripheral surface are the angular centers of the joints. When manufacturing the cup part of the outer ring of the fixed type constant velocity universal joint offset from each other in the axial direction in the opposite direction, the track groove part is moved to the outer diameter side by subjecting the pipe material to cold pressing. Increase diameter Or, after reducing the diameter of the portion of the track inter-groove on the inner diameter side, and forming the concave spherical inner circumferential surface by cutting, the production method of the outer ring of the constant velocity universal joint.   A plurality of track grooves extending in the axial direction on the cylindrical inner peripheral surface, an outer ring comprising a cup portion and a shaft portion formed with a concave spherical inner peripheral surface, and an inner ring formed with a plurality of track grooves extending in the axial direction on the convex spherical outer peripheral surface A torque transmission ball rotatably incorporated in a ball raceway formed by a track groove of the outer ring and a track groove of the inner ring, a pocket for accommodating the torque transmission ball, a concave spherical inner peripheral surface of the outer ring, and A cage having a convex spherical outer peripheral surface and a concave spherical inner peripheral surface that engage with the convex spherical outer peripheral surface of the inner ring, and the center of the convex spherical outer peripheral surface of the cage and the center of the concave spherical inner peripheral surface are the angular centers of the joints. In producing the cup portion of the outer ring of the fixed type constant velocity universal joint offset from each other in the axial direction opposite to each other in the axial direction, by subjecting the cylindrical material formed by deep drawing from the plate material to cold pressing, G Characterized in that the concave spherical inner peripheral surface is formed by cutting after expanding the portion of the hook groove to the outer diameter side or reducing the portion between the track grooves to the inner diameter side, Manufacturing method for outer ring of constant velocity universal joint.   An outer ring composed of a cup portion and a shaft portion formed with a plurality of track grooves extending in the axial direction on the concave spherical inner peripheral surface, an inner ring formed with a plurality of track grooves extending in the axial direction on the convex spherical outer peripheral surface, and a track groove of the outer ring And a torque transmission ball that is rotatably incorporated in a ball raceway formed by a track groove of the inner ring and a pocket for accommodating the torque transmission ball, and a concave spherical inner peripheral surface of the outer ring and a convex spherical outer peripheral surface of the inner ring A cage having a convex spherical outer peripheral surface and a concave spherical inner peripheral surface engaged with each other, and the center of the convex spherical outer peripheral surface and the center of the concave spherical inner peripheral surface of the cage are opposite to each other in the axial direction from the angular center of the joint. When manufacturing the cup portion of the outer ring of the fixed type constant velocity universal joint that is offset by the same distance in the direction, the long portion having the cross-sectional shape of the cylindrical inner peripheral surface of the cup portion and the track groove by cold drawing. Molding the 抜材, after cutting to a predetermined length, and forming the concave spherical inner circumferential surface by cutting, the production method of the outer ring of the constant velocity universal joint.   The constant velocity universal joint according to claim 5, 6 or 7, wherein after molding the cup portion of the outer ring, surface hardening treatment is performed, and a necessary range is joined to the shaft portion having been hardened by induction hardening. Manufacturing method of outer ring.