Sliding type constant velocity universal joint

Abstract

The invention provides a holder for a sliding constant velocity universal joint, a sliding constant velocity universal joint, and a method for manufacturing the holder for a sliding constant velocity universal joint. An annular tapered surface (19a ') is formed in a region adjacent to a region (15') for forming a groove in an inner peripheral surface (19 ') provided in a region (12') for forming a large-diameter ring section of a retainer prototype (5 '), the tapered surface (19a') having a diameter reduced toward the other axial side (a region side for forming a small-diameter ring section). Thereafter, the cage prototype (5 ') is punched from the inner diameter side to form a large-diameter ring section (12), a small-diameter ring section (13), a plurality of pillar sections (14), and a plurality of grooves (15), and the angle with respect to the axis of a second region (19b) of the inner peripheral surface (19) of the large-diameter ring section (12) adjacent to the grooves (15) is made smaller than the maximum angle (alpha) with respect to the axis of a first region (19a) of the inner peripheral surface (19) of the large-diameter ring section (12) adjacent to the pillar sections (14).

Description

Technical Field

[0001] The invention relates to a sliding constant velocity universal coupling. Background Art

[0002] Constant velocity universal joints used in drive shafts and propeller shafts of automobiles are broadly divided into sliding types that allow both angular displacement and axial relative movement between the two shafts, and fixed types that allow angular displacement but not axial relative movement between the two shafts.

[0003] As sliding constant velocity universal joints, known types include double-offset constant velocity universal joints (DOJs) that use balls as rolling elements for transmitting rotational torque, and tripod-type constant velocity universal joints (TJs) that use rollers as rolling elements. Double-offset constant velocity universal joints are widely used due to their low manufacturing costs and minimal internal oscillation in the direction of rotation. For example, Patent Document 1 below describes a double-offset constant velocity universal joint that has been reduced in weight and size by increasing the number of balls from 6 to 8. Furthermore, Patent Document 2 below describes a double-offset constant velocity universal joint that has been further reduced in weight and size by increasing the maximum operating angle to over 30°.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 10-73129

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 2007-85488 Summary of the Invention

[0008] Problems to be solved by the invention

[0009] Double offset constant velocity universal couplings such as Figure 13 As shown, it includes an outer coupling member 101 having a linear rolling groove 105 formed on a cylindrical inner circumference, an inner coupling member 102 having a linear rolling groove 106 formed on a spherical outer circumference, a plurality of balls 103 arranged between the rolling groove 105 of the outer coupling member 101 and the rolling groove 106 of the inner coupling member 102, and a retainer 104 for retaining the plurality of balls 103.

[0010] The retainer 104 comprises a large-diameter ring portion 107, a small-diameter ring portion 108, a plurality of columns 109 connecting these portions axially, and a plurality of grooves 110 disposed circumferentially between the columns 109. The outer circumference of the retainer 104 is provided with a spherical portion 111 that slides with the cylindrical inner circumference of the outer coupling member 101. The inner circumference of the retainer 104 is provided with a spherical portion 112 that fits with the spherical outer circumference of the inner coupling member 102. To facilitate assembly of the inner coupling member 102 to the inner circumference of the retainer 104, a cylindrical surface 113 is provided on the inner circumference of the large-diameter ring portion 107 of the retainer 104.

[0011] In the manufacturing process of the retainer 104, the retainer 104 is formed by forging and turning. Figure 14 After the substantially cylindrical retainer prototype 104' is formed as shown, Figure 15 As shown in FIG. 1 , the retainer prototype 104 ′ is punched out from the inner diameter side using a punch 201 to form a groove 110. By punching out the groove 110, as shown in FIG. Figure 17 As shown in the enlarged figure, the area adjacent to the groove 110 in the cylindrical surface 113 provided on the inner circumferential surface of the large-diameter ring portion 107 is larger than that before the punching process (refer to Figure 17 As a result, the inner diameter end of the inner peripheral surface of the groove 110 (hereinafter referred to as the "groove surface 114") is displaced toward the outer diameter side by the amount of the collapse P. Figure 16 As shown in the figure, when the constant velocity universal joint rotates at the maximum working angle, the ball 103 ( Figure 16 The lower ball in the groove surface 114 may sometimes come into contact with the inner diameter end of the groove surface 114. Figure 17 When the inner diameter end of groove surface 114 displaces toward the outer diameter side due to the occurrence of collapse P, as shown by the solid line, the contact portion (contact ellipse) between ball 103 and groove surface 114 extends toward the inner diameter side of groove surface 114. When ball 103 escapes from groove surface 114 in this manner, the edge portion (inner diameter end) of groove surface 114 may be damaged, or ball 103 may be damaged by the edge portion of groove surface 114, adversely affecting the strength and life of the constant velocity universal joint.

[0012] For example, if the cylindrical surface 113 of the retainer 104 is pre-formed to have a smaller diameter by the amount of collapse P, the inner diameter end of the groove surface 114 can be positioned at the correct radial position even if collapse P occurs, thereby avoiding the aforementioned reduction in strength and durability. However, when the cylindrical surface 113 of the retainer 104 is reduced in diameter, the following assembly problems may occur.

[0013] The inner coupling member 102 is assembled to the inner periphery of the retainer 104 in the following steps. Figure 18As shown, the retainer 104 and the inner coupling member 102 are arranged coaxially, and the phase (circumferential position) of the column portion 109 of the retainer 104 is matched with the phase of the raceway groove 106 of the inner coupling member 102. In this state, the inner coupling member 102 is inserted into the inner circumference of the retainer 104 while being fitted into the cylindrical surface 113 of the retainer 104. Thereafter, the retainer 104 and the inner coupling member 102 are rotated relative to each other in the circumferential direction, and as shown in FIG. Figure 19 The phase of the grooves 110 of the retainer 104 is matched to the phase of the raceway grooves 106 of the inner coupling member 102 as shown.

[0014] In this way, in order to be able to assemble the inner joint member 102 on the inner periphery of the retainer 104, the outer diameter Dn of the inner joint member 102 (see Figure 18 ) needs to be larger than the diameter Dc of the cylindrical surface 113 of the retainer 104 (refer to Figure 18 ) is small. Therefore, when the diameter Dc of the cylindrical surface 113 of the retainer 104 is reduced by the amount of collapse P as described above, the outer diameter Dn of the inner joint member 102 also needs to be reduced. When the outer peripheral surface of the inner joint member 102 is reduced in diameter, the raceway groove 106 of the inner joint member 102 becomes shallower, resulting in disadvantages such as a decrease in torque load capacity.

[0015] Therefore, in fact, Figure 20 As shown, the cylindrical surface 113 of the retainer prototype 104' is pre-formed to a small diameter (diameter Dcc). After the recess 110 is punched, the cylindrical surface 113 is subjected to additional machining (secondary turning) to increase its diameter (diameter Dc). This allows the inner diameter end of the recess surface 114 to be positioned at the desired radial position even if the cylindrical surface 113 collapses, and the depth of the raceway groove 106 of the inner joint member 102 is ensured. However, this additional machining of the retainer 104 results in increased costs.

[0016] Therefore, an object of the present invention is to prevent a malfunction of a sliding type constant velocity universal joint caused by collapse caused by punching out a groove of a cage without incurring an increase in cost.

[0017] Solutions to Problems

[0018] In order to solve the above-mentioned problem, the present invention provides a method for manufacturing a retainer of a sliding constant velocity universal joint, wherein the retainer of the sliding constant velocity universal joint comprises: a large diameter ring portion, which is arranged on one axial side; a small diameter ring portion, which is arranged on the other axial side; and a plurality of column portions, which connect the large diameter ring portion and the small diameter ring portion in the axial direction, wherein a plurality of grooves are formed between the circumferential directions of the plurality of column portions, the curvature center (O1) of the spherical portion arranged on the outer peripheral surface is offset by a distance (F) to one axial side relative to the coupling center (O), and the curvature center (O2) of the spherical portion arranged on the inner peripheral surface is offset by the distance (F) to the other axial side relative to the coupling center (O), wherein:

[0019] The manufacturing method of the retainer of the sliding constant velocity universal joint comprises:

[0020] a step of forming a substantially cylindrical retainer prototype;

[0021] forming an annular tapered surface whose diameter decreases toward the other axial side in a region adjacent to the region where the groove is to be formed, on the inner circumferential surface of the region where the large-diameter ring portion of the retainer prototype is to be formed; and

[0022] The retainer prototype is punched out from the inner diameter side to form the large diameter ring portion, the small diameter ring portion, the plurality of column portions, and the plurality of grooves, and the angle of the second area adjacent to the groove in the inner circumferential surface of the large diameter ring portion relative to the axis is smaller than the maximum angle of the first area adjacent to the column portion in the inner circumferential surface of the large diameter ring portion relative to the axis.

[0023] As described above, in the present invention, before the groove is punched out, an annular tapered surface is formed in the area adjacent to the groove within the predetermined area of ​​the inner circumference of the large-diameter ring portion of the substantially cylindrical retainer prototype, which decreases in diameter as it approaches the other axial direction. Subsequently, the retainer prototype is punched out from the inner diameter side, causing a collapse in the second area adjacent to the groove within the inner circumference of the large-diameter ring portion. At this time, by pre-forming a tapered surface in the annular area encompassing the second area, the angle of the tapered surface in the second area relative to the axis decreases due to the collapse, resulting in a substantially cylindrical surface. This allows the inner diameter end of the groove surface, which contacts the ball, to be positioned at the desired radial position, preventing the ball from dislodging from the groove surface even when the coupling is operating at a high angle, thereby improving strength and durability at high operating angles.

[0024] On the other hand, the first region of the inner circumference of the large-diameter ring portion, adjacent to the column, is largely unaffected by the punching process of the groove, leaving a tapered surface and resulting in a smaller diameter than the second region adjacent to the groove. When the inner coupling member is assembled within the inner circumference of the retainer, the second region becomes the area facing the raceway groove of the inner coupling member. Therefore, even if the diameter is reduced, it does not interfere with the inner coupling member. Therefore, there is no need to increase the inner circumference of the retainer through additional processing, avoiding increased costs. Furthermore, by providing the tapered surface in the first region, the wall thickness near the boundary between the large-diameter ring portion and the column is increased, thereby improving the strength of the retainer.

[0025] According to the above, the present invention can be characterized as a retainer for a sliding constant velocity universal joint, comprising: a large-diameter ring portion provided on one axial side; a small-diameter ring portion provided on the other axial side; and a plurality of column portions connecting the large-diameter ring portion and the small-diameter ring portion in the axial direction, wherein a plurality of grooves are formed between the plurality of column portions in the circumferential direction.

[0026] The center of curvature (O1) of the spherical portion provided on the outer peripheral surface is offset by a distance (F) to one side in the axial direction relative to the center (O) of the coupling, and the center of curvature (O2) of the spherical portion provided on the inner peripheral surface is offset by the distance (F) to the other side in the axial direction relative to the center (O) of the coupling, wherein:

[0027] A first region whose diameter decreases as it approaches the other axial side is provided in a region adjacent to the column portion on the inner circumferential surface of the large-diameter ring portion.

[0028] A second region having an angle with respect to the axis smaller than a maximum angle with respect to the axis of the first region is provided in a region adjacent to the groove on the inner circumferential surface of the large-diameter ring portion.

[0029] Preferably, a cylindrical surface having the same diameter as the end of the tapered surface on one axial side and continuous over the entire circumference is provided in a region adjacent to one axial side of the tapered surface on the inner circumferential surface of the retainer prototype. In this case, a cylindrical third region having the same diameter as the end of the tapered surface on one axial side and continuous over the entire circumference is provided in a region adjacent to one axial side of the first region (tapered surface) and the second region (substantially cylindrical surface) on the inner circumferential surface of the large-diameter ring portion of the retainer after the groove is formed.

[0030] The tapered surface can be formed, for example, by lathing the inner circumferential surface of the retainer prototype. In this case, the surfaces of the first and second regions of the retainer after the grooves are formed have lathing marks that are continuous in the circumferential direction.

[0031] Effects of the Invention

[0032] As described above, according to the present invention, it is possible to prevent a malfunction of a sliding type constant velocity universal joint caused by collapse due to punching of the groove of the cage without incurring a cost increase due to additional processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is an axial cross-sectional view of a sliding constant velocity universal joint according to an embodiment of the present invention, and is Figure 2 Cross-sectional view at the BOB line.

[0034] Figure 2 yes Figure 1 Axis-orthogonal cross-sectional view at line AA.

[0035] Figure 3 This is a perspective view of the retainer of the sliding type constant velocity universal joint.

[0036] Figure 4 yes Figure 3 Cross-sectional view at line CC.

[0037] Figure 5 yes Figure 3 Cross-sectional view at line BB.

[0038] Figure 6 It is an enlarged cross-sectional view of the above retainer.

[0039] Figure 7 This is a cross-sectional view of the retainer prototype (retainer before turning).

[0040] Figure 8 This is a perspective view of the retainer prototype (the retainer before the grooves are formed).

[0041] Figure 9 This is an axial cross-sectional view of the above-mentioned retainer prototype.

[0042] Figure 10 It is a cross-sectional view of the vicinity of the large-diameter ring portion of the retainer.

[0043] Figure 11 The diagram shows the assembly steps of the retainer and the inner joint member, and is a front view of a state where the outer peripheral surface of the inner joint member is fitted into the inner peripheral surface of the large-diameter ring portion of the retainer, as seen from the axial direction.

[0044] Figure 12 This is a front view of the cage and the inner joint member in a state where assembly is completed, as seen from the axial direction.

[0045] Figure 13 This is an axial cross-sectional view of a conventional sliding constant velocity universal joint.

[0046] Figure 14This is an axial cross-sectional view of a cage prototype of a conventional cage.

[0047] Figure 15 This is a cross-sectional view showing how a groove is punched out in a retainer prototype.

[0048] Figure 16 It shows Figure 13 An axial cross-sectional view of a sliding constant velocity universal joint at its maximum operating angle.

[0049] Figure 17 yes Figure 13 An enlarged cross-sectional view of the retainer of a sliding constant velocity universal joint.

[0050] Figure 18 It shows Figure 13 The present invention is a diagram showing the assembly steps of the retainer and the inner coupling member of the sliding constant velocity universal joint, and is a front view obtained by observing the state in which the outer peripheral surface of the inner coupling member is fitted into the inner peripheral surface of the large diameter ring portion of the retainer from the axial direction.

[0051] Figure 19 Observed from the axial direction Figure 13 A front view of the sliding constant velocity universal joint with the retainer and inner coupling member after assembly.

[0052] Figure 20 It is a cross-sectional view showing the diameter of the inner peripheral surface of the large-diameter ring portion of a conventional cage before and after the additional processing.

[0053] Description of Reference Numerals

[0054] 1 Sliding constant velocity universal coupling

[0055] 2 Outer coupling member

[0056] 3 Inner coupling member

[0057] 4 balls

[0058] 5 Retainer

[0059] 5' retainer prototype

[0060] 7 Roller groove

[0061] 9 Roller groove

[0062] 12 large diameter ring

[0063] 12' Area where the large diameter ring portion is to be formed

[0064] 13 Small diameter ring

[0065] 14 Column

[0066] 15 grooves

[0067] 15' Predetermined area for groove formation

[0068] 16 Spherical part

[0069] 17 Conical surface

[0070] 18 spherical part

[0071] 19 inner circumference

[0072] 19a First region (conical surface)

[0073] 19a' conical surface

[0074] 19b Second area (roughly cylindrical surface)

[0075] 19c The third area (cylindrical surface)

[0076] 19c' cylindrical surface

[0077] 20 groove surface

[0078] 21 Inner diameter end of groove surface

[0079] O Coupling Center

[0080] O1 Center of curvature of the spherical portion of the outer peripheral surface of the retainer

[0081] The center of curvature of the spherical portion of the inner surface of the O2 retainer

[0082] P collapse. DETAILED DESCRIPTION

[0083] Hereinafter, embodiments of the sliding type constant velocity universal joint according to the present invention will be described in detail with reference to the accompanying drawings.

[0084] Figure 1 as well as Figure 2 The overall structure of a double offset constant velocity universal joint 1 (hereinafter simply referred to as “constant velocity universal joint 1 ”) which is one of sliding constant velocity universal joints assembled to a drive shaft of a vehicle is shown.

[0085] The constant velocity universal joint 1 of this embodiment comprises an outer coupling member 2 in the shape of a cup with one axial end open, an inner coupling member 3 arranged on the inner periphery of the outer coupling member 2, a plurality of balls 4 as rolling elements, and a retainer 5 for retaining the plurality of balls 4. The inner component 10 including the inner coupling member 3, the balls 4, and the retainer 5 can be accommodated in the inner periphery of the outer coupling member 2 so as to be displaced in the axial direction. The end of the shaft not shown is coupled to the shaft hole 11 of the inner coupling member 3 by spline fitting. It should be noted that in the following description, Figure 1 The axial direction of the outer coupling member 2 and the inner coupling member 3 in the state of the working angle 0° shown is called the "axial direction". Figure 1 The bottom side of the outer coupling member 2 in the axial direction in the state of the working angle 0° shown ( Figure 1 The right side of the coupling is called the "coupling depth side". Figure 1 The opening side of the outer coupling member 2 in the axial direction in the state of the working angle 0° shown ( Figure 1 The left side of the coupling is called the "open side of the coupling."

[0086] On the cylindrical inner circumferential surface 6 of the outer coupling member 2, linear raceway grooves 7 extending in the axial direction are formed at equal intervals at multiple locations in the circumferential direction. On the spherical outer circumferential surface 8 of the inner coupling member 3, linear raceway grooves 9 extending in the axial direction are formed at equal intervals at multiple locations in the circumferential direction. The balls 4 are arranged one-to-one between the raceway grooves 7 of the outer coupling member 2 and the raceway grooves 9 of the inner coupling member 3, which are opposite in the radial direction, to transmit rotational torque between the two coupling members 2 and 3. In the illustrated example, eight raceway grooves 7 and 9 are each formed, and eight balls 4 are provided. The number of raceway grooves 7, 9 and balls 4 is not limited to the above, and can be, for example, 5, 6, or 7.

[0087] The retainer 5 has a large-diameter ring portion 12 provided on the deep side of the coupling, a small-diameter ring portion 13 provided on the open side of the coupling, a plurality of columns 14 connecting the large-diameter ring portion 12 and the small-diameter ring portion 13 in the axial direction, and a plurality of grooves 15 provided between the plurality of columns 14 in the circumferential direction. The outermost diameter portion of the large-diameter ring portion 12 has a larger diameter than the outermost diameter portion of the small-diameter ring portion 13. The balls 4 are retained one-to-one in each groove 15. A spherical portion 16 that slides with the cylindrical inner circumferential surface 6 of the outer coupling member 2 and tapered surfaces 17 provided on both axial sides of the spherical portion 16 are formed on the outer circumferential surface of the retainer 5. A spherical portion 18 that slides with the spherical outer circumferential surface 8 of the inner coupling member 3 is formed on the inner circumferential surface of the retainer 5.

[0088] The centers of curvature O1 of the spherical portion 16 on the outer circumferential surface of the retainer 5 and the center of curvature O2 of the spherical portion 18 on the inner circumferential surface are offset axially by an equal distance F relative to the coupling center O (the intersection of a plane passing through the centers of all balls 4 and the axis of the coupling). In the illustrated example, the center of curvature O1 of the spherical portion 16 on the outer circumferential surface of the retainer 5 is offset toward the coupling depth relative to the coupling center O, while the center of curvature O2 of the spherical portion 18 on the inner circumferential surface of the retainer 5 is offset toward the coupling opening relative to the coupling center O. Consequently, when an operating angle is applied between the outer coupling member 2 and the inner coupling member 3, the balls 4 retained in the grooves 15 of the retainer 5 always remain within the plane bisecting the operating angle at any operating angle, thereby ensuring constant velocity between the outer coupling member 2 and the inner coupling member 3. Furthermore, the balls 4 held in the retainer 5 roll on the raceway grooves 7 of the outer joint member 2 , so that the inner member 10 is slidable in the axial direction relative to the outer joint member 2 .

[0089] The entire axial area of ​​the large diameter ring portion 12 is arranged at a position closer to the coupling depth side than the spherical portion 18 of the inner circumferential surface of the retainer 5. That is, the end of the groove 15 on the coupling depth side is arranged at a position closer to the coupling depth side than the spherical portion 18. The inner circumferential surface 19 of the large diameter ring portion 12 is formed into a substantially cylindrical shape. Figure 3 As shown, the inner circumferential surface 19 of the large diameter ring portion 12 has a first region 19a adjacent to the coupling depth side of the column portion 14, a second region 19b adjacent to the coupling depth side of the groove 15, and a third region 19c adjacent to the coupling depth side of the first region 19a and the second region 19b.

[0090] The first region 19a is as follows Figure 4 As shown in FIG. 1 , the second region 19b is tapered and narrows toward the coupling opening (right side in the figure). Figure 5 As shown, the first region 19a has a substantially cylindrical surface with an angle relative to the axis that is smaller than the maximum angle α of the first region 19a relative to the axis (the angle at the circumferential center of the first region 19a), and in the illustrated example, is parallel to the axis. The first region 19a and the second region 19b are circumferentially adjacent to each other, and near their boundary 19d, the angle relative to the axis gradually changes from α to approximately 0°.

[0091] The third area 19c is as follows Figure 3As shown, the third region 19c has a continuous cylindrical surface along its entire circumference. The diameter of the third region 19c is the same as that of the coupling-deeper end portions of the first and second regions 19a, 19b. A circumferential boundary line 19e is formed at the boundary between the first and third regions 19a, 19c. Meanwhile, the second and third regions 19b, 19c, continue in a substantially continuous cylindrical surface, so their boundary line 19f is thinner than the boundary line 19e between the first and third regions 19a, 19c.

[0092] Thus, in the present embodiment, the second region 19b adjacent to the groove 15 in the inner circumferential surface of the large diameter ring portion 12 of the retainer 5 is in a roughly cylindrical shape continuous with the third region 19c, so that the inner diameter end of the second region 19a, that is, the inner diameter end 21 of the inner circumferential surface of the groove 15 (the groove surface 20) is not displaced to the outer diameter side, but is arranged at the desired radial position. In the example shown in the figure, the inner diameter end 21 of the groove surface 20 is arranged at a radial position substantially the same as that of the third region 19c of the inner circumferential surface 19 of the large diameter ring portion 12. Specifically, the inner diameter end 21 of the groove surface 20 is arranged within a radial range of ±0.1 mm relative to the radial position of the third region 19c. Thus, when the constant velocity universal joint 1 rotates in a state where the maximum working angle is taken (refer to Figure 16 ),like Figure 6 As shown, even if the ball 4 contacts the inner diameter end 21 of the groove surface 20, the end Q of the ball 4 on the coupling depth side is arranged at a position closer to the outer diameter side than the inner diameter end 21 of the groove surface 20, and the contact portion (contact ellipse) between the ball 4 and the groove surface 20 can be accommodated in the groove surface 20, thereby preventing the ball 4 from contacting the inner diameter end 21 (edge ​​portion) of the groove surface 20.

[0093] In addition, by providing a tapered first area 19a in the area adjacent to the column portion 14 on the inner circumferential surface of the large diameter ring portion 12 of the retainer 5, the large diameter ring portion 12 is locally thickened, thereby improving the strength of the retainer 5, especially the strength near the boundary between the large diameter ring portion 12 and the column portion 14.

[0094] Retainer 5 is manufactured through a forging process, a turning process, a groove punching process, a heat treatment process, and a grinding process. It should be noted that, hereinafter, retainer 5 after the forging process and before the turning process is referred to as "retainer prototype 5", and retainer 5 after the turning process and before the formation of groove 15 is referred to as "retainer prototype 5'". Furthermore, in the axial direction of retainer 5 (or retainer prototype 5', 5"), the side with the large-diameter ring portion 12 is referred to as the "axial large-diameter side", and the side with the small-diameter ring portion 13 is referred to as the "axial small-diameter side".

[0095] First, in a forging process, a retainer prototype 5 is formed by, for example, hot forging (see Figure 7). The retainer prototype 5" is roughly cylindrical. In the subsequent turning process, the retainer prototype 5" is turned to form Figure 7 The dotted line and Figure 8 The retainer prototype 5' shown in FIG. The retainer prototype 5' has a large-diameter ring portion forming area 12', a small-diameter ring portion forming area 13', a column portion forming area 14', and a groove forming area 15'. Figure 9 As shown in the figure, the retainer prototype 5' has a tapered surface 19a' formed on the inner circumferential surface 19' of the planned forming area 12' of the large-diameter ring portion, which is formed continuously over the entire circumference of the area adjacent to the planned forming area 15' of the groove in the inner circumferential surface 19' of the planned forming area 12' of the large-diameter ring portion. The tapered surface 19a' is tapered as it approaches the axially smaller diameter side ( Figure 9 The cylindrical surface 19c' is formed continuously over the entire circumference of the region adjacent to the axially larger diameter side of the tapered surface 19a'. The end portion of the axially larger diameter side of the tapered surface 19a' has the same diameter as the cylindrical surface 19c'.

[0096] In the groove punching step, the retainer prototype 5' is punched out from the inner diameter side to form the groove 15 (see Figure 15 ). By punching the retainer prototype 5' from the inner diameter side, Figure 10 As shown, the area adjacent to the groove 15 in the tapered surface 19a' collapses and approaches a cylindrical surface, forming a substantially cylindrical second area 19b in this area. On the other hand, the area adjacent to the column 14 in the tapered surface 19a' is hardly affected by the blanking process and thus remains as the tapered first area 19a. The maximum angle α of this first area 19a with respect to the axis (see Figure 4 ) and the angle α' of the tapered surface 19a' of the retainer prototype 5' relative to the axis (refer to Figure 9 ) are approximately equal. Furthermore, cylindrical surface 19c' formed on the axially larger diameter side of tapered surface 19a' in retainer prototype 5' is also largely unaffected by the blanking process, so this region becomes cylindrical third region 19c. At this time, the angle α' relative to the axis and the axial width of tapered surface 19a' formed in retainer prototype 5' are set through the turning process so that the axially smaller diameter end of second region 19b, i.e., inner diameter end 21 of recessed groove surface 20, is positioned at approximately the same radial position as cylindrical third region 19c.

[0097] In the heat treatment step, heat treatments such as carburizing, quenching, and tempering are applied to the cage 5. In the present embodiment, a hardened layer formed by the heat treatment is formed on the entire surface of the cage 5.

[0098] During the grinding process, necessary parts of the retainer 5 are ground. In this embodiment, the spherical portion 16 on the outer circumferential surface, the spherical portion 18 on the inner circumferential surface, and the groove surface 20 of the retainer 5 are ground. At this time, areas other than the spherical portion 18 on the inner circumferential surface of the retainer 5 are not ground. For example, the inner circumferential surface 19 of the large-diameter ring portion 12 is not ground. Therefore, the inner circumferential surface 19 of the large-diameter ring portion 12 becomes a lathe-machined surface, with lathe marks remaining along the circumferential direction. Specifically, the first region 19a and the second region 19b of the inner circumferential surface 19 of the large-diameter ring portion 12 have circumferentially continuous lathe marks. Furthermore, the third region 19c of the inner circumferential surface 19 of the large-diameter ring portion 12 also has circumferentially continuous lathe marks.

[0099] Next, a procedure for inserting the inner joint member 3 into the inner periphery of the cage 5 will be described.

[0100] First, if Figure 11 As shown, the inner joint member 3 is coaxially arranged on the axially larger diameter side (forward in the drawing) of the retainer 5, with the phase (circumferential position) of the column portion 14 of the retainer 5 aligned with the phase of the raceway groove 9 of the inner joint member 3. In this state, the inner joint member 3 is fitted into the inner circumferential surface 19 of the large-diameter ring portion 12 of the retainer 5. In this state, a tapered first region 19a is provided in the circumferential region of the column portion 14 of the inner circumferential surface 19 of the large-diameter ring portion 12 of the retainer 5. Its minimum diameter Dc1 is smaller than the outer diameter Dn of the inner joint member 3. However, since the first region 19a is positioned opposite the raceway groove 9 of the inner joint member 3, it does not interfere with the inner joint member 3. On the other hand, the second region 19b of the inner circumferential surface 19 of the large-diameter ring portion 12 of the retainer 5, which is provided in the circumferential region of the groove 15, is a substantially cylindrical surface continuous with the cylindrical third region 19c, and has a diameter Dc2 that is larger than the outer diameter Dn of the inner joint member 3. Therefore, the inner joint member 3 can be inserted into the inner circumference of the retainer 5 while being fitted into the inner circumferential surface 19 of the large-diameter ring portion 12 of the retainer 5.

[0101] Then, after the center of curvature of the spherical outer peripheral surface 8 of the inner coupling member 3 is aligned with the center of curvature of the spherical portion 18 of the inner peripheral surface of the retainer 5, the retainer 5 and the inner coupling member 3 are rotated relative to each other in the circumferential direction. Figure 12 As shown, the phases of the grooves 15 of the retainer 5 and the raceway grooves 9 of the inner joint member 3 are matched. As a result, the spherical outer surface 8 of the inner joint member 3 and the spherical portion 18 of the inner circumference of the retainer 5 are fitted together, completing the assembly of the two.

[0102] As described above, in the constant velocity universal joint 1 of this embodiment, after the recessed grooves 15 are punched, the inner joint member 3 can be inserted into the inner periphery of the retainer 5 without performing additional processing on the inner peripheral surface 19 of the large diameter ring portion 12 of the retainer 5 .

[0103] The present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, the center of curvature O1 of the spherical portion 16 of the outer circumferential surface of the retainer 5 is positioned on the coupling's rearward side, and the center of curvature O2 of the spherical portion 18 of the inner circumferential surface of the retainer 5 is positioned on the coupling's opening side. However, conversely, the center of curvature O1 of the spherical portion 16 of the outer circumferential surface of the retainer 5 may be positioned on the coupling's opening side, and the center of curvature O2 of the spherical portion 18 of the inner circumferential surface of the retainer 5 may be positioned on the coupling's rearward side.

[0104] Furthermore, in the above-described embodiment, the outer joint member 2 is shown as being cup-shaped, but the present invention is not limited thereto and may be, for example, a cylindrical shape with both axial ends open.

[0105] The constant velocity universal joint 1 described above is not limited to the drive shaft of an automobile, but can also be applied to the propeller shaft of an automobile, the power transmission shaft of an industrial machine, and the like.

Claims

1. A retainer for a sliding constant velocity universal joint, comprising: A large-diameter ring portion, which is arranged on one side in the axial direction; A small-diameter ring portion provided on the other axial side; and A plurality of columnar portions connecting the large-diameter ring portion and the small-diameter ring portion in the axial direction, A plurality of grooves are formed between the plurality of pillars in the circumferential direction. The center of curvature (O1) of the spherical portion provided on the outer peripheral surface is offset in the axial direction by a distance (F) relative to the center (O) of the coupling. The center of curvature (O2) of the spherical portion provided on the inner peripheral surface is offset axially to the other side by the distance (F) relative to the center (O) of the coupling. in, A first region whose diameter decreases as it approaches the other axial side is provided in a region adjacent to the column portion on the inner circumferential surface of the large-diameter ring portion. A second region having an angle with respect to the axis smaller than a maximum angle with respect to the axis of the first region is provided in a region adjacent to the groove on the inner circumferential surface of the large-diameter ring portion.

2. The retainer of the sliding constant velocity universal joint according to claim 1, wherein: A cylindrical third region having the same diameter as the ends of the first and second regions on one axial side and continuous around the entire circumference is provided in a region adjacent to one axial side of the first and second regions on the inner circumferential surface of the large-diameter annular portion.

3. The retainer of the sliding constant velocity universal joint according to claim 1, wherein: Turning marks continuous in the circumferential direction are provided on the surfaces of the first region and the second region.

4. A sliding constant velocity universal coupling, wherein: The sliding constant velocity universal coupling has: The retainer according to claim 1; an inner coupling member having a spherical outer peripheral surface that fits into the spherical portion of the inner peripheral surface of the retainer, and having a plurality of linear raceway grooves formed on the spherical outer peripheral surface; an outer joint member having a cylindrical inner peripheral surface on which the spherical portion of the outer peripheral surface of the retainer slides, and having a plurality of linear raceway grooves formed on the cylindrical inner peripheral surface; and The balls are arranged between the raceway groove of the outer joint member and the raceway groove of the inner joint member and are accommodated in the groove of the retainer.

5. A method for manufacturing a retainer of a sliding constant velocity universal joint, the retainer of the sliding constant velocity universal joint comprising: A large-diameter ring portion, which is arranged on one side in the axial direction; A small-diameter ring portion provided on the other axial side; and A plurality of columnar portions connecting the large-diameter ring portion and the small-diameter ring portion in the axial direction, A plurality of grooves are formed between the plurality of pillars in the circumferential direction. The center of curvature (O1) of the spherical portion provided on the outer peripheral surface is offset in the axial direction by a distance (F) relative to the center (O) of the coupling. The center of curvature (O2) of the spherical portion provided on the inner peripheral surface is offset axially to the other side by the distance (F) relative to the center (O) of the coupling. in, The manufacturing method of the retainer of the sliding constant velocity universal joint comprises: a step of forming a substantially cylindrical retainer prototype; forming an annular tapered surface whose diameter decreases toward the other axial side in a region adjacent to the region where the groove is to be formed, on the inner circumferential surface of the region where the large-diameter ring portion of the retainer prototype is to be formed; and The retainer prototype is punched out from the inner diameter side to form the large diameter ring portion, the small diameter ring portion, the plurality of column portions, and the plurality of grooves, and the angle of the second area adjacent to the groove in the inner circumferential surface of the large diameter ring portion relative to the axis is smaller than the maximum angle of the first area adjacent to the column portion in the inner circumferential surface of the large diameter ring portion relative to the axis.

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