JP2010281431A - Shaft coupling and constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shaft coupling and a constant velocity universal joint capable of attaining compactness, and capable of easily performing even attaching-detaching work in a limited range. <P>SOLUTION: This invention has a central shaft member 71 for fitting a mating side shaft 70, and a flange member 72 for fitting the central shaft member 71 and detachably connected in a state of being superposed on a flange surface 50 of an outside joint member of the universal joint. A key groove 75 for fitting a key 73 arranged on the mating side shaft 70, is formed on an inner diameter surface 71a of the central shaft member 71. A male spline 76 is formed on an outer diameter surface 71b of the central shaft member 71. A female spline 80 for fitting a male spline 76 of the central shaft member 71 is formed on an inner diameter surface 72a of the flange member 72. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a constant velocity universal joint and a shaft coupling that connects a shaft and an outer joint member of the constant velocity universal joint.

  Patent Literature 1, Patent Literature 2, and the like disclose shaft couplings that connect the outer joint member of the constant velocity universal joint and the shaft. In these cases, spline fitting is used.

  That is, as shown in FIG. 17, the shaft joint of Patent Document 1 connects the outer ring 4 that is the outer joint member of the constant velocity universal joint 1 and the shaft 31. The constant velocity universal joint 1 in this case includes the outer ring 4 as an outer joint member in which a plurality of curved track grooves 3 are formed on a spherical inner peripheral surface 2, and the track groove of the outer ring 4 on a spherical outer peripheral surface 5. An inner ring 7 as an inner joint member in which a plurality of curved track grooves 6 paired with 3 are formed, and a plurality of balls 8 interposed between the track grooves 3 of the outer ring 4 and the track grooves 6 of the inner ring 7. And a cage 9 that is disposed between the outer ring 4 and the inner ring 7 and holds the ball 8.

  A female spline 10 is formed on the inner surface of the inner ring 7, and the male spline 13 at the end of the shaft 12 is fitted into the female spline 10 with the end of the shaft 12 fitted into the inner ring 7. Further, the opening on the side opposite to the shaft coupling of the outer ring 4 is closed by a boot 15. That is, the boot 15 includes a large diameter portion 15a, a small diameter portion 15b, and a bellows portion 15c that connects the large diameter portion 15a and the small diameter portion 15b. The large diameter portion 15 a is externally fitted to the outer ring 4 and tightened by the boot band 16, and the small diameter portion 15 b is externally fitted to the boot mounting portion 17 of the shaft 12 and tightened by the boot band 16.

  The shaft coupling includes a joint shaft 20 attached to the outer ring 4 of the constant velocity universal joint, and a shaft member 21 fitted into the joint shaft 20. The joint shaft 20 includes a main body portion 20a having a female spline 22 formed on the inner diameter surface, and an outer flange portion 20b that is connected to an end portion of the main body portion 20a on the constant velocity universal joint side. An outer flange portion 23 is provided on the shaft coupling side of the outer ring 4 of the constant velocity universal joint 1. The outer flange portion 23 of the outer ring 4 and the outer flange portion 20 b of the joint shaft 20 are overlapped with each other, and the outer flange portion 23 and the outer flange portion 20 b are connected by a bolt and nut connection 25.

  The shaft member 21 includes a main body shaft 27 having a male spline 26 formed on the outer diameter surface thereof, and an outer flange portion 28 provided on the main body shaft 27 on the base end side (the opposite constant velocity universal joint side). For this reason, when the main body shaft 27 is fitted into the main body portion 20 a of the joint shaft 20, the male spline 26 of the main body shaft 27 is fitted to the female spline 22 of the main body portion 20 a of the joint shaft 20.

  An adapter 30 is connected to the shaft member 21, and a mating shaft 31 to be connected to the adapter 30 is fitted. That is, the adapter 30 includes a main body portion 33 having a key groove 32 formed on the inner diameter surface, and an outer flange portion 34 provided on the constant velocity universal joint side of the main body portion 33. The outer flange portion 34 of the adapter 30 and the outer flange portion 28 of the shaft member 21 are overlapped with each other, and the outer flange portion 34 and the outer flange portion 28 are connected to each other by the bolt and nut coupling 35. A key 36 is provided on the shaft 31, and the key 36 is fitted in the key groove 32 of the adapter 30.

  Conventionally, there are some which do not have the shaft member 21 as shown in FIG. That is, the outer flange portion 34 of the adapter 30 is connected to the outer flange portion 23 of the outer ring 4 via the bolt and nut coupling 35.

  Moreover, the thing of the said patent document 2 provides the coupling part of the outer ring | wheel of a constant velocity universal joint, and inserts the other party shaft in this coupling part. That is, a female spline is formed on the inner diameter surface of the coupling portion, and the end of the shaft is fitted into the coupling, and the male spline at the end of the shaft is fitted into the female spline of the coupling.

Japanese Patent Laid-Open No. 9-257047 JP 2007-64361 A

  As shown in FIG. 17, in the thing of patent document 1, the coupling shaft 20 and the adapter 30 are arrange | positioned along an axial direction, Comprising: A comparatively big space is required. Moreover, during the connecting operation, the joint shaft 20 is attached to the outer ring 4 of the constant velocity universal joint, the male spline 26 of the shaft member 21 is fitted to the female spline 22 of the joint shaft 20, and the adapter 30 is further connected to the shaft. While attaching to the member 21, it is necessary to fit the other shaft 31 into the adapter 30. For this reason, the connecting operation is time-consuming.

  Also, with respect to the one shown in FIG. 16, it is necessary to remove the bolt-nut connection 35 at the time of the connecting operation, which takes time.

  The one described in Patent Document 2 is limited to spline fitting with the mating shaft, and a male spline needs to be formed on the mating shaft. For this reason, the application range is limited and the versatility is poor.

  Therefore, in view of such circumstances, the present invention is intended to provide a shaft coupling and a constant velocity universal joint that can be made compact and can be easily attached and detached within a limited range.

  The shaft joint of the present invention is a shaft joint that connects an outer joint member of a universal joint and a counterpart shaft, and a central shaft member into which the counterpart shaft is inserted, and the universal shaft member is inserted into the universal joint. A flange member that is detachably connected to the flange surface of the outer joint member of the joint in a detachable manner is formed, and on the inner diameter surface of the central shaft member, a key groove that fits a key provided on the counterpart shaft is formed, A male spline is formed on the outer diameter surface of the central shaft member, and a female spline in which the male spline of the central shaft member is fitted is formed on the inner diameter surface of the flange member.

  When the mating shaft is fitted into the central shaft member, the key of the mating shaft is fitted into the key groove on the inner diameter surface of the central shaft member, and the mating shaft and the central shaft member are connected so as to transmit torque. Also, if the center shaft member is fitted into the flange member, the female spline on the inner diameter surface of the flange member and the male spline on the outer diameter surface of the center shaft member can be fitted to transmit torque between the flange member and the center shaft member. Connected to The flange member is connected to the outer joint member of the constant velocity universal joint. For this reason, the counterpart shaft and the outer joint member of the constant velocity universal joint are coupled so as to be able to transmit torque. Moreover, since the central shaft member is fitted into the flange member, the axial length of the shaft joint can be made compact.

  It is preferable to provide a chamfered portion at the insertion start end of the male spline of the central shaft member and set the chamfered angle of the chamfered portion to 15 ° to 60 °. By providing the chamfered portion, the center shaft member can be smoothly fitted into the flange member.

  The central shaft member is provided with a protruding shaft portion that protrudes from the chamfered portion at the insertion start end of the male spline toward the insertion start side, and the outer diameter corner portion of the distal end surface of the protruding shaft portion is rounded, and the outer diameter corner portion The curvature radius may be 2 mm or more. By providing the projecting shaft portion on the central shaft member, the projecting shaft portion can first be inserted into the flange member when the center shaft member starts to be fitted into the flange member, and the fitting operation is stabilized.

  It is preferable that the dimension from the front end surface of the protruding shaft portion to the chamfered portion at the insertion start end of the male spline is 3 mm or more. By setting it as such a dimension, the protrusion to the flange member of a protrusion shaft part is stabilized.

  It is preferable to provide a relief portion constituted by a large-diameter hole at the insertion start end of the flange member. By providing the relief portion in this manner, the relief portion serves as a fitting guide for the center shaft member to the flange member, and the fit of the center shaft member to the flange member can be improved. In this case, when the outer diameter dimension of the protruding shaft portion of the central shaft member is H1, and the small diameter dimension H2 of the concave portion of the central shaft member is (H1 = H2). Further, when the large diameter dimension of the protruding portion of the central shaft member is H3 and the inner diameter dimension of the thinned portion of the flange member is H4, (H4−H3) = (0.1 to 0.5) mm. Is preferred.

  The hardness of the male spline can be HRC20 to HRC30, and the hardness of the female spline can be HRC58 to HRC63. By providing such a hardness difference, the low hardness side, that is, the male spline side is more easily worn than the female spline side. For this reason, even if the male spline side is worn due to use or the like, there is often no wear on the female spline side. Therefore, in such a case, the worn side (male spline side) may be replaced.

  It is preferable to apply solid lubrication to at least one of the male spline and the female spline. Here, solid lubrication treatment means one or several types of solid lubricants such as molybdenum disulfide, graphite (graphite), fluororesin (ethylene tetrafluoride, etc.), tungsten disulfide, metal oxide, and various organic resins. This is a treatment for forming a dry film obtained by dispersing the material into a paint and coating it. This solid lubricating treatment layer (solid lubricating treatment film) is excellent in wear resistance, heat resistance, and corrosion resistance. In addition, since the coefficient of friction is low, the insertability can be improved.

  The constant velocity universal joint of the present invention is a constant velocity universal joint having a connection structure for connecting to a counterpart shaft, the connection structure including a central shaft member into which the counterpart shaft is inserted, A fitting portion into which the shaft member is fitted is provided, the fitting portion is provided in the outer joint member, and a key groove in which a key provided in the counterpart shaft is fitted is formed on the inner diameter surface of the central shaft member. At the same time, a male spline is formed on the outer diameter surface of the central shaft member, and a female spline is formed on the inner diameter surface of the fitted portion.

  According to the constant velocity universal joint of the present invention, when the mating shaft is fitted into the central shaft member, the key of the mating shaft is fitted into the key groove on the inner diameter surface of the central shaft member, and the mating shaft and the central shaft are fitted. The member is connected to be able to transmit torque. Further, if the central shaft member is inserted into the insertion portion, the female spline on the inner diameter surface of the insertion portion and the male spline on the outer diameter surface of the central shaft member are fitted, and the insertion portion and the central shaft member are Connected to transmit torque. Therefore, the counterpart shaft and the outer joint member of the constant velocity universal joint are connected so as to be able to transmit torque.

  In the shaft joint of the present invention, the counterpart shaft and the outer joint member of the constant velocity universal joint are connected so as to be able to transmit torque, and a stable torque transmission function is exhibited. In addition, since the central shaft member is fitted into the flange member, the axial length of the shaft joint can be made compact, and a small space in the arrangement range can be achieved.

  By providing the chamfered portion, the center shaft member can be smoothly fitted into the flange shaft member. In addition, the outer diameter corner portion of the tip surface of the projecting shaft portion is rounded, the projecting shaft portion is provided on the center shaft member, or the thinning portion is provided at the fitting start end of the flange member, thereby changing the center shaft member. It is possible to improve the insertion workability at the start of the insertion into the flange member.

  By adding a hardness difference to the spline, it is not necessary to replace parts that are not worn, and the replacement work can be simplified to achieve cost reduction.

  If at least one of the male spline and the female spline is subjected to solid lubrication, the center shaft member can be smoothly inserted (inserted) into the flange member.

  In the constant velocity universal joint of the present invention, the mating shaft and the fitted portion of the outer joint member are connected so as to be able to transmit torque, and a stable torque transmission function is exhibited. In addition, since the central shaft member is inserted into the insertion portion, the axial length can be reduced, and the space in the arrangement range can be reduced.

It is sectional drawing of the shaft coupling which shows the 1st Embodiment of this invention. It is sectional drawing of the shaft coupling shown in the said FIG. It is sectional drawing which shows the isolation | separation state of the shaft coupling shown in the said FIG. It is a cross-sectional view of a mating shaft. It is a cross-sectional view of the central shaft member of the shaft coupling shown in FIG. It is a front view of the flange member of the shaft coupling shown in FIG. It is sectional drawing of the shaft coupling which shows the 2nd Embodiment of this invention. It is a front view of the shaft coupling shown in the said FIG. The other side shaft is shown, (a) is a principal part side view, (b) is sectional drawing. It is a side view of the center shaft member of the shaft coupling shown in the said FIG. It is a front view of the center shaft member of the shaft coupling shown in the said FIG. It is a front view of the shaft coupling shown in the said FIG. It is sectional drawing of the shaft coupling shown in the said FIG. It is sectional drawing which shows the constant velocity universal joint of this invention. It is sectional drawing which shows the other constant velocity universal joint of this invention. It is sectional drawing of the conventional shaft coupling. It is sectional drawing of the other conventional shaft coupling.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  1 and 2 are cross-sectional views showing a connection state between a shaft joint and a universal joint according to the present invention. The universal joint in this case is a fixed constant velocity universal joint using balls as rolling elements, and an outer ring 54 as an outer joint member in which a plurality of curved track grooves 53 are formed on a spherical inner peripheral surface 52. And an inner ring 57 as an inner joint member in which a plurality of curved track grooves 56 paired with the track grooves 53 of the outer ring 54 are formed on the spherical outer peripheral surface 55, and the track grooves 53 of the outer ring 54 and the tracks of the inner ring 57. A plurality of balls 58 interposed between the grooves 56 and a cage 59 that is disposed between the outer ring 54 and the inner ring 57 and holds the balls 58 are provided.

  A female spline 60 is formed on the inner diameter surface of the inner ring 57, and the male spline 63 at the end of the shaft 62 is fitted into the female spline 60 with the end of the shaft 62 fitted into the inner ring 57. In this case, retaining rings 64a and 64b are attached to both end portions of the male spline 63 of the shaft 62 to constitute a stopper. Further, the opening on the side opposite to the shaft joint of the outer ring 54 is closed by a boot 65. That is, the boot 65 includes a large diameter portion 65a, a small diameter portion 65b, and a bellows portion 65c that connects the large diameter portion 65a and the small diameter portion 65b. The large-diameter portion 65 a is externally fitted to the outer ring 54 and fastened by the boot band 66, and the small-diameter portion 65 b is externally fitted to the boot mounting portion 67 of the shaft 62 and fastened by the boot band 66.

  The outer ring 54 includes a main body portion 54a having a track groove 53 provided on the inner diameter surface, and a disk-shaped flange portion 54b constituting the bottom wall of the main body portion 54a. In this case, the outer diameter surface of the main body portion 54a is a cylindrical surface, and the outer diameter portion of the flange portion 54b protrudes to the outer diameter side from the main body portion 54a. Moreover, the circumferential direction convex part 69 which protrudes in the anti-body part side is provided in the outer peripheral part of this flange part 54b.

  The shaft coupling according to the present invention includes a central shaft member 71 into which the mating shaft 70 is inserted, and a flange member 72 into which the central shaft member is inserted. In this case, the end of the mating shaft 70 (the end fitted into the flange member 72) includes a key 73. As shown in FIG. 3, the key 73 is provided with an axial concave groove 74 on the outer diameter surface of the end of the counterpart shaft 70, and the key 73 is fitted into the concave groove 74. Further, the outer diameter surface of the end portion of the mating shaft 70 is fitted in contact with the inner diameter surface of the central shaft member 71. In this case, there may be a slight gap between the outer diameter surface of the end of the mating shaft 70 and the inner diameter surface 71 a of the central shaft member 71.

  As shown in FIGS. 3 and 5, the central shaft member 71 is formed of a cylindrical body in which a key groove 75 into which the key 73 is fitted is formed on the inner diameter surface 71 a. A male spline 76 is formed on the outer diameter surface 71 b of the central shaft member 71. In other words, the male spline 76 is configured by providing the ridges 77 having a rectangular cross section on the outer diameter surface 71b of the central shaft member 71 at a predetermined pitch (60 ° pitch in the illustrated example) along the circumferential direction. For this reason, the concave line part 78 is formed between the convex line parts 77 and 77 adjacent to the circumferential direction. That is, the male spline 76 is formed by alternately arranging the ridges 77 and the recesses 78 along the circumferential direction.

  The flange member 72 is formed of a disc body having the same axial length as the axial direction length of the central shaft member 71, and a female spline 80 is provided on the inner diameter surface 72a thereof. That is, as shown in FIG. 2 and FIG. 6, etc., it is configured by providing concave grooves 81 having a rectangular cross section at a predetermined pitch (60 ° pitch) along the circumferential direction on the inner diameter surface 72a. For this reason, the protruding item | line part 82 is formed between the adjacent grooved grooves 81 and 81 in the circumferential direction. That is, the female spline 80 is formed by alternately arranging the groove grooves 81 and the protrusions 82 along the circumferential direction.

  Then, the ridge 77 of the male spline 76 of the central shaft member 71 is fitted in the concave groove 81 of the female spline 80, and the ridge of the female spline 80 is fitted to the concave ridge 78 of the male spline 76 of the central shaft member 71. The part 82 is fitted. At this time, the outer diameter surface 71b of the central shaft member 71 and the inner diameter surface 72a of the flange member 72 are fitted in contact.

  As shown in FIG. 2, the flange member 72 is provided with screw holes 83 at a 120 ° pitch along the circumferential direction, and further, a circumferential notch 84 is provided on the constant velocity universal joint side of the outer diameter surface 72b. ing. That is, the flange member 72 can be overlaid on the flange surface 50 of the flange portion 54b of the constant velocity universal joint, and in this overlaid state, the circumferential convex portion of the flange portion 54b is formed in the circumferential notch 84 of the flange member 72. 69 is fitted. The flange portion 54 b is provided with a through hole 85. A screw member 86 is inserted into the through hole 85 and screwed into the screw hole 83 of the flange member 72. As a result, the flange portion 54b of the constant velocity universal joint and the flange member 72 are integrated.

  Further, the hardness of the male spline 76 can be HRC20 to HRC30, and the hardness of the female spline 80 can be HRC58 to HRC63. That is, in the male spline 76, the range in which the hardness is HRC20 to HRC30 is at least the surfaces of the ridges 77 and the ridges 78. In this case, the tempering process is performed. Here, the tempering treatment is a treatment in which a steel product is tempered to a relatively high temperature (about 400 ° C. or higher) after quenching and hardening to a troostite or sorbite structure. In other words, refining refers to an operation of adjusting the steel quality by refining the crystal grains of the steel to substantially improve the toughness.

  In the female spline 80, the range in which the hardness is HRC58 to HRC63 is at least the surface of the groove 81 and the protrusion 82. In this case, it comprises by performing an induction hardening tempering process. The induction hardening and tempering process is a process of making a hardened hardened layer on the surface layer by rapidly heating the surface of the object to be heated to the quenching temperature using high frequency induction heating and further rapidly cooling the surface. Abrasion resistance can be improved and mechanical properties can be enhanced.

  Preferably, at least one of the male spline 76 and the female spline 80 is subjected to solid lubrication. Here, solid lubrication treatment means one or several types of solid lubricants such as molybdenum disulfide, graphite (graphite), fluororesin (ethylene tetrafluoride, etc.), tungsten disulfide, metal oxide, and various organic resins. This is a treatment for forming a dry film obtained by dispersing the material into a paint and coating it. This solid lubricating treatment layer (solid lubricating treatment film) is excellent in wear resistance, heat resistance, and corrosion resistance. It also has a low coefficient of friction.

  According to the shaft coupling of the present invention, when the mating shaft 70 is fitted into the central shaft member 71, the key 73 of the mating shaft 70 is fitted into the key groove 75 of the inner diameter surface 71 a of the central shaft member 71, The side shaft 70 and the central shaft member 71 are connected so that torque can be transmitted. Further, when the center shaft member 71 is fitted into the flange member 72, the female spline 80 on the inner diameter surface 72 a of the flange member 72 and the male spline 76 on the outer diameter surface 71 b of the center shaft member 71 are fitted to each other. And the central shaft member 71 are coupled so as to be able to transmit torque. Further, since the flange member 72 is connected to the outer ring 54 of the constant velocity universal joint, the counterpart shaft 70 and the outer ring 54 of the constant velocity universal joint are connected so as to transmit torque.

  Thus, in the shaft coupling of the present invention, the mating shaft 70 and the outer ring 54 of the constant velocity universal joint are coupled so as to be able to transmit torque, and a stable torque transmission function is exhibited. In addition, since the central shaft member 71 is fitted into the flange member 72, the axial length of the shaft joint can be made compact, and a space in the arrangement range can be reduced.

  By providing a hardness difference between the male spline 76 and the female spline 80, the low hardness side, that is, the male spline 76 side is more easily worn than the female spline 80 side. For this reason, even if the male spline 76 is worn due to use or the like, there is often no wear on the female spline 80 side. Therefore, in such a case, it is only necessary to replace the worn side (male spline side), and the replacement work can be simplified to achieve cost reduction.

  In this embodiment, the hardness of the male spline 76 is HRC20 to HRC30, and the hardness of the female spline 80 is HRC58 to HRC63. For this reason, the minimum hardness difference is HRC58−HRC30 and HRC28. The maximum hardness difference is HRC63−HRC20 and HRC43. That is, there is a hardness difference between HRC28 and HRC43. If the hardness difference is smaller than this range, the hardness difference is too small to make a difference in wear. On the contrary, if the hardness difference is larger than this range, the hardness difference is too large and the higher spline is inferior in toughness and is likely to be damaged.

  Next, FIG. 7 shows another embodiment. The outer ring 54 of the constant velocity universal joint in this case includes a cylindrical main body portion 54c having a track groove 53 formed on the inner diameter surface, and a shaft joint of the main body portion 54c. And an outer flange portion 54d provided on the side. Further, the counterpart shaft 70 includes a key 73 as shown in FIG. The key 73 is provided with an axial groove 74 on the outer diameter surface of the counterpart shaft 70, and the key 73 is fitted in the groove 74.

  The central shaft member 71 is formed of a cylindrical body having a key groove 100 formed along the axial direction on the inner diameter surface 101, and a male spline 103 of the outer diameter surface 102 is formed. That is, as shown in FIGS. 10 and 11, the male spline 103 is formed on the outer diameter surface of the central shaft member 71 along the circumferential direction at a predetermined pitch (60 ° pitch in the illustrated example) with a rectangular section 105 having a rectangular cross section. It is comprised by providing. For this reason, the concave stripe part 106 is formed between the convex stripe parts 105 and 105 adjacent to the circumferential direction. That is, the male spline 103 is formed by alternately arranging the ridges 105 and the ridges 106 along the circumferential direction.

  A chamfered portion 105 a is formed at the insertion start end of the ridge 105. The chamfered portion 105a is formed by forming a tapered surface that is inclined toward the inner diameter side toward the insertion start end side. The taper angle θ of the taper surface is, for example, 15 ° to 60 °.

  Further, the central shaft member 71 is provided with a protruding shaft portion 107 that protrudes toward the insertion start end side from the protruding portion 105. That is, the taper surface of the ridge 105 is slightly retracted from the tip surface of the central shaft member 71 (tip surface 107a of the projecting shaft 107). In this case, when the dimension from the tip surface 107a to the chamfered portion 105a of the ridge 105 is B, it is set to 3 mm or more. The outer diameter corner portion 108 of the distal end surface 107a of the protruding shaft portion 107 is rounded, and the radius of curvature R of the outer diameter corner portion 108 is 2 mm or more.

  As shown in FIG. 13, the flange member 72 includes a cylindrical main body 90 having a female spline 89 provided on the inner diameter surface 90 a, and an outer flange 91 provided on the constant velocity universal joint side of the cylindrical main body 90. Consists of. As shown in FIG. 12, the female spline 89 is configured by providing concave grooves 120 having a rectangular cross section at a predetermined pitch (60 ° pitch) along the circumferential direction on the inner diameter surface 90a. For this reason, the convex strip 121 is formed between the concave strips 120 adjacent to each other in the circumferential direction. That is, the female spline 89 is formed by alternately arranging the groove grooves 120 and the protrusions 121 along the circumferential direction.

  In addition, a large-diameter portion 122 is provided in an opening portion on the outer flange portion side of the inner diameter surface 90a of the cylindrical main body portion 90, and an opening portion on the side opposite to the outer flange portion of the inner diameter surface 90a of the cylindrical main body portion 90 is provided. A blind portion 123 constituted by a large-diameter hole made of a circumferential cutout is provided. A chamfer 123 a is provided at the opening of the thinning portion 123.

  The outer flange portion 91 of the flange member 72 and the flange surface 50 which is the back surface of the outer flange portion 54 d of the outer ring 54 are overlapped with each other, and these are connected by a bolt and nut connection 95. That is, the through hole 92 is provided in the outer flange portion 91 of the flange member 72 at a predetermined pitch (120 ° pitch) along the circumferential direction, and the outer flange portion 54d of the outer ring 54 has a predetermined pitch (in the circumferential direction). Through holes 93 are provided at a pitch of 120 °. Then, the through hole 92 of the flange member 72 and the through hole 93 of the outer flange portion 54d of the outer ring 54 are aligned, and the bolt member 96 constituting the bolt nut coupling 95 is inserted through the through holes 92, 93. The bolt member 96 is connected by screwing a nut member 97.

  By the way, when the outer diameter dimension of the protruding shaft portion 107 is H1 (see FIG. 10) and the smaller diameter dimension H2 (see FIG. 11) of the concave strip portion 106 of the central shaft member 71 is (H1 = H2). Further, when the large diameter dimension of the ridge 105 of the central shaft member 71 is H3 (see FIG. 10) and the inner diameter dimension of the thin portion 123 of the flange member 72 is H4 (see FIG. 13), (H4-H3 ) = (0.1 to 0.5) mm. That is, the inner diameter dimension of the thin portion 123 of the flange member 72 is slightly larger than the large diameter dimension of the convex portion 105 of the central shaft member 71.

  In the shaft coupling shown in FIG. 7, by providing the chamfered portion 105 a at the fitting start end of the male spline 103 of the central shaft member 71, the central shaft member 71 can be smoothly fitted into the flange member 72. In particular, by setting the chamfer angle of the chamfered portion 105a to 15 ° to 60 °, the chamfered portion 105a can be made more stable. That is, if the angle is less than 15 °, the insertion start end of the male spline 103 may be too acute and the insertion start end may be damaged or damaged. If the angle exceeds 60 °, the function of the chamfered portion 105a may not be exhibited. There is.

  By providing the central shaft member 71 with a protruding shaft portion 107 that protrudes more toward the insertion start side than the chamfered portion 105a at the insertion start end of the male spline 103, when the central shaft member 71 starts to be fitted into the flange member 72, first, The protruding shaft portion 107 can be inserted into the flange member 72, and the fitting operation is stabilized. The outer diameter corner portion 108 of the tip end surface 107a of the protruding shaft portion 107 is rounded and the curvature radius R of the outer diameter corner portion 108 is 2 mm or more, so that the fitting is smooth. If the radius of curvature R of the outer diameter corner portion 108 is less than 2 mm, the outer diameter corner portion 108 does not have a round shape, and the effect of making the round shape is not achieved. If the radius of curvature R is too large, the entire tip surface 107a may be convex and the protruding shaft portion 107 may not be configured. For this reason, the radius of curvature R is preferably 2 mm or more and less than B dimension-1 mm, although it varies depending on the outer diameter of the central shaft member 71 and the like.

  It is preferable that the dimension B from the front end surface 107a of the protruding shaft portion 107 to the chamfered portion 105a at the insertion start end of the male spline 103 is 3 mm or more. By setting it as such a dimension, the protrusion to the flange member 72 of the protrusion shaft part 107 is stabilized. That is, if the dimension B is less than 3 mm, the protruding amount of the tip surface 107a of the protruding shaft portion 107 is small, and the function as the protruding shaft portion 107 cannot be exhibited.

  By providing the thinning portion 123 at the insertion start end of the central shaft member 71 of the flange member 72, the thinning portion 123 serves as a fitting guide to the flange member 72 of the central shaft member 71, thereby improving the fitting property. it can. In this case, if (H4-H3) is smaller than (0.1-0.5) mm, H3 and H4 are substantially the same, and the insertion guide to the flange member 72 of the central shaft member 71 is constituted. On the contrary, if it is larger than (0.1 to 0.5) mm, H4 becomes too larger than H3, and the center shaft member 71 is large when the center shaft member 71 is fitted into the thin portion 123. Having “play”, the fitting of the male spline 103 of the central shaft member 71 and the female spline 89 of the flange member 72 may not be stable. In addition, the axial direction length of this thin part 123 shall be 2 mm to B dimension mm, for example. When it is shorter than 2 mm or longer than the dimension B, the function as an insertion guide is not exhibited.

  Even in the shaft coupling shown in FIG. 7, the hardness of the male spline 103 may be HRC20 to HRC30, and the hardness of the female spline 89 may be HRC58 to HRC63. Further, at least one of the male spline 103 and the female spline 89 may be subjected to solid lubrication.

  By the way, although the said embodiment was a shaft coupling, as shown in FIG. 14 and FIG. 15, this invention may be a constant velocity universal joint which comprises the structure of the shaft coupling of the said embodiment. That is, the constant velocity universal joint shown in FIGS. 14 and 15 is provided with a connection structure M for connecting to the counterpart shaft 70.

  In the connecting structure M of the constant velocity universal joint shown in FIG. 14, a central shaft member 71 (with the same structure as the shaft joint shown in FIG. 1) into which the mating shaft is inserted, and the central shaft member 71 are inserted. A fitting portion 130 is provided. The fitted portion 130 is provided in the outer ring 54 that is an outer joint member. This insertion part 130 has the same structure as the flange member 72 of the shaft coupling shown in FIG. That is, a female spline 80 that fits the male spline 76 of the central shaft member 71 is formed on the inner diameter surface of the fitted portion 130.

  For this reason, in the constant velocity universal joint shown in FIG. 14, when the mating shaft 70 is fitted into the central shaft member 71, the key 73 of the mating shaft 70 is fitted into the key groove 75 on the inner diameter surface of the central shaft member 71. Thus, the counterpart shaft 70 and the central shaft member 71 are coupled so as to be able to transmit torque. Further, if the central shaft member 71 is fitted into the fitted portion 130, the female spline 80 on the inner diameter surface of the fitted portion 130 and the male spline 76 on the outer diameter surface of the central shaft member 71 are fitted to each other. 130 and the central shaft member 71 are coupled so as to be able to transmit torque. As a result, the counterpart shaft 70 and the outer ring 54 of the constant velocity universal joint are connected so as to transmit torque.

  As described above, in the constant velocity universal joint shown in FIG. 14, the counterpart shaft 70 and the outer ring 54 are connected so as to be able to transmit torque, and a stable torque transmission function is exhibited. In addition, since the central shaft member 71 is inserted into the insertion portion 130, the axial length can be reduced, and the space in the arrangement range can be reduced.

  That is, the constant velocity universal joint coupling structure M shown in FIG. 14 includes a central shaft member 71 (with the same structure as the shaft coupling shown in FIG. 1) into which the mating shaft is inserted, and the shaft coupling shown in FIG. Since the fitted portion 130 having the same structure as that of the flange member 72 is provided, the same effects as the shaft coupling shown in FIG.

  The constant velocity universal joint shown in FIG. 15 has a central shaft member 71 (with the same structure as the shaft coupling shown in FIG. 7) into which the mating shaft 70 is fitted, like the connection structure M of the constant velocity universal joint shown in FIG. And a fitted portion 131 into which the central shaft member 71 is fitted. This fitting part 131 is provided in the outer ring 54 which is an outer joint member. This fitting part 131 has the same structure as the flange member 72 of the shaft coupling shown in FIG.

  That is, the fitted portion 131 corresponds to a cylindrical main body portion in which the female spline 89 is provided on the inner diameter surface. Therefore, when the mating shaft 70 is fitted into the central shaft member 71, the key 73 of the mating shaft 70 is fitted into the key groove 100 on the inner diameter surface of the central shaft member 71, and the mating shaft 70 and the central shaft member are fitted. 71 is connected to be able to transmit torque. Further, if the central shaft member 71 is fitted into the fitted portion 131, the female spline 89 on the inner diameter surface of the fitted portion 131 and the male spline 103 on the outer diameter surface of the central shaft member 71 are fitted, and the fitted portion. 131 and the central shaft member 71 are connected so that torque can be transmitted. As a result, the counterpart shaft 70 and the outer ring 54 of the constant velocity universal joint are connected so as to transmit torque.

  As described above, even in the constant velocity universal joint shown in FIG. 15, the mating shaft 70 and the outer ring 54 are connected so as to be able to transmit torque, and a stable torque transmission function is exhibited. In addition, since the central shaft member 71 is inserted into the insertion portion 130, the axial length can be reduced, and the space in the arrangement range can be reduced.

  That is, the constant velocity universal joint (constant velocity universal joint shown in FIG. 15) has a connecting structure M, a central shaft member 71 (with the same structure as the shaft joint shown in FIG. 7) into which the mating shaft 70 is fitted, Since the fitted portion 130 having the same structure as that of the flange member 72 of the shaft coupling shown in FIG. 7 is provided, the same effects as the shaft coupling shown in FIG.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in each of the above-described embodiments, the protrusions of the male splines 76 and 103 are provided. Although the number of 77 and 105 is six, it is not restricted to this, and the increase / decrease is arbitrary. Further, the cross-sectional shape of the ridges 77 and 105 is not limited to a rectangular shape, and may be a triangular shape or a trapezoidal shape. As keys formed on the mating shaft 70, various keys such as a flat key, a key, and a sink key can be used. The male spline 103 shown in FIG. 7 may be used for the male spline 76 shown in FIG.

  When the hardness difference is made between the male splines 76 and 103 and the female splines 80 and 89, the female splines 80 and 89 are made higher than the male splines 76 and 103 in the above embodiment. The 76, 103 side may be made higher than the female splines 80, 89 side. Moreover, the case where such a hardness difference is not given may be sufficient.

  When performing the solid lubrication treatment, it may be performed only on the male splines 76 and 103 side, only on the female splines 80 and 89 side, or on the male splines 76 and 103 side and the female splines 80 and 89 side. . In the shaft coupling, the constant velocity universal joint to be connected is not limited to the fixed type constant velocity universal joint, but may be a sliding type constant velocity universal joint. Further, the constant velocity universal joint provided with the connection structure M is not limited to a fixed type constant velocity universal joint, and may be a sliding type constant velocity universal joint.

50 Flange surface 70 Mating shaft 71 Central shaft member 71a Inner diameter surface 71b Outer diameter surface 72 Flange member 72a Inner diameter surface 73 Key 75, 100 Key groove 76, 103 Male spline 80, 89 Female spline 90a Inner diameter surface 101 Inner diameter surface 102 Outer diameter Surface 105a Chamfered portion 107 Protruding shaft portion 107a Tip surface 108 Outer diameter corner portion 123 Brazing portion 130, 131 Inserted portion

Claims (9)

A shaft joint that connects the outer joint member of the universal joint and the counterpart shaft,
A center shaft member into which the mating shaft is inserted, and a flange member into which the center shaft member is inserted and detachably connected to the flange surface of the outer joint member of the universal joint in a superposed manner; A key groove for fitting a key provided on the mating shaft is formed on the inner diameter surface of the center shaft member, a male spline is formed on the outer diameter surface of the center shaft member, and a male spline of the center shaft member is formed on the inner diameter surface of the flange member. A shaft joint characterized by forming a female spline that fits.   The shaft coupling according to claim 1, wherein a chamfered portion is provided at a fitting start end of the male spline of the central shaft member, and a chamfering angle of the chamfered portion is set to 15 ° to 60 °.   The central shaft member is provided with a protruding shaft portion that protrudes from the chamfered portion at the insertion start end of the male spline toward the insertion start side, and the outer diameter corner portion of the distal end surface of the protruding shaft portion is rounded, and the outer diameter corner portion The shaft coupling according to claim 2, wherein the radius of curvature is 2 mm or more.   The shaft coupling according to claim 3, wherein the dimension from the tip end surface of the protruding shaft portion to the chamfered portion at the insertion start end of the male spline is 3 mm or more.   The shaft coupling according to any one of claims 1 to 4, wherein a thinning portion constituted by a large-diameter hole is provided at a fitting start end of the flange member.   When the outer diameter dimension of the protruding shaft portion of the central shaft member is H1, and the small diameter dimension H2 of the concave strip portion of the central shaft member is (H1 = H2), the large diameter of the convex strip portion of the central shaft member The dimension is H3, and when the inner diameter dimension of the flange portion of the flange member is H4, (H4-H3) = (0.1-0.5) mm. The shaft coupling according to any one of the above.   The shaft coupling according to any one of claims 1 to 6, wherein the male spline has a hardness of HRC20 to HRC30, and the female spline has a hardness of HRC58 to HRC63.   The shaft coupling according to any one of claims 1 to 7, wherein solid lubrication treatment is performed on at least one of the male spline and the female spline. A constant velocity universal joint having a connection structure for connecting to a mating shaft,
The connection structure includes a central shaft member into which the mating shaft is inserted, and a fitted portion into which the central shaft member is fitted, the fitted portion is provided in an outer joint member, and the central shaft member A key groove for fitting a key provided on the mating shaft is formed on the inner diameter surface, a male spline is formed on the outer diameter surface of the center shaft member, and a male spline of the center shaft member is formed on the inner diameter surface of the fitting portion. A constant velocity universal joint characterized by forming a female spline that fits.

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