JP2011252547A - Constant velocity universal joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a constant velocity universal joint that is superior in productivity and can smoothly absorb axial directional displacement when colliding by reducing the number of parts and the number of machining steps.SOLUTION: The constant velocity universal joint has an outside joint member 3 and an inside joint member 6 transmitting torque between the outside joint member 3 and the same while allowing angular displacement. A shaft 11 is fitted into a shaft hole of the inside joint member 6 and the inside joint member 6 and the shaft 11 are integrally coupled via an uneven fitting structure M with which the whole area of a fitting and contacting site 38 with a protrusion 31 and a recess 32 comes into closer contact. shaft directional press fitting load in press fitting is made larger than the axial directional sliding resistance of the joint inside part S arranged within the outside joint member 3. The axial directional press fitting load is made smaller than the axial directional impact load applied to the joint inside part S.

Description

  The present invention relates to a constant velocity universal joint used in power transmission systems of automobiles and various industrial machines, and more particularly, to a constant velocity universal joint for an automobile propulsion shaft (propeller shaft).

  The propeller shaft (propulsion shaft) is a rotating shaft that moves forward and backward in the center of the body of an FR vehicle or 4WD vehicle, and is a shaft that transmits the rotational force of the engine to a differential gear or the like. For this reason, in order to improve safety at the time of vehicle collision, some propeller shafts have a function / mechanism for absorbing axial displacement at the time of collision in order to release the impact force (Patent Document 1 and Patent Document 2). ).

  The one described in Patent Document 1 is free of constant velocity when an axial input load acts on the constant velocity universal joint from the drive shaft at the time of a vehicle collision, and the constant velocity universal joint slides into the driven shaft. The joint internal part of the joint is configured to allow the inside of the inner curl to pass through without hitting the inner curl. As a result, a slide movement with a sufficient stroke amount becomes possible, and the impact can be sufficiently absorbed by this large slide movement amount.

  By the way, this constant velocity universal joint is formed by joining the cylindrical holding part constituting the outer race and the pipe shaft part by friction welding, and the outer curl and the inner curl are generated during the friction welding. To do.

  Patent Document 2 discloses a fixing device for fixing an inner ring of a constant velocity universal joint to a propeller shaft, and releasing the fixing of the inner ring by the fixing device when an axial direction exceeding a predetermined value acts on the propeller shaft. And a release device. For this reason, relative movement in the axial direction is allowed between the constant velocity universal joint and the intermediate shaft of the propeller shaft. This reduces the shock when an excessive axial force acts on the vehicle body.

  As the fixing device, a clip attached to a circumferential groove formed in the shaft is used. The cross-sectional shape of the circumferential groove is set so that the clip is detached from the circumferential groove when an axial direction exceeding a predetermined value acts on the propeller shaft.

JP 2003-146098 A Japanese Patent Laid-Open No. 9-295517

  In the thing of the said patent document 1, it is necessary to make the internal diameter of a pipe shaft part larger than a joint internal component (components which consist of an inner joint member, a ball | bowl, etc.). For this reason, the application is limited. Moreover, in the thing of the said patent document 2, it is necessary to make a circumferential groove | channel into a special shape, and there exists a problem in workability, it is inferior in productivity, and becomes high-cost.

  In view of the above problems, the present invention provides a constant velocity universal joint that is excellent in productivity by reducing the number of parts and the number of processing steps, and can absorb axial displacement smoothly at the time of a collision. .

  A first constant velocity universal joint according to the present invention includes an outer joint member and an inner joint member that transmits torque while allowing angular displacement between the outer joint member and a shaft hole of the inner joint member. A constant velocity universal joint in which a shaft is inserted and the inner joint member and the shaft are integrally connected through an uneven fitting structure, and a convex portion extending in the axial direction on the outer diameter surface of the shaft hole insertion portion of the shaft. The shaft hole insertion portion of the shaft is press-fitted into the shaft hole of the inner joint member, and a part of the inner surface of the inner joint member is extruded and / or cut by this press-fitting, and the convex portion is formed on the inner surface of the inner joint member. Forming the concave and convex fitting structure along the axial direction to form the concave and convex fitting structure in which the entire fitting contact portion between the convex and concave portions is in close contact, and the axial press-fitting load of the press-fitting, Loaded on joint internal parts including the inner joint member It is obtained by less than in the direction impact load.

  A second constant velocity universal joint of the present invention includes an outer joint member and an inner joint member that transmits torque while allowing angular displacement between the outer joint member and a shaft hole of the inner joint member. A constant velocity universal joint in which a shaft is inserted and the inner joint member and the shaft are integrally connected through an uneven fitting structure, and a convex portion extending in the axial direction on the outer diameter surface of the shaft hole insertion portion of the shaft. The shaft hole insertion portion of the shaft is press-fitted into the shaft hole of the inner joint member, and a part of the inner surface of the inner joint member is extruded and / or cut by this press-fitting, and the convex portion is formed on the inner surface of the inner joint member. Forming the concave and convex fitting structure along the axial direction to form the concave and convex fitting structure in which the entire fitting contact portion between the convex and concave portions is in close contact, and the axial press-fitting load of the press-fitting, Axial sliding of joint internal parts including the inner joint member It is made larger than the anti.

  A third constant velocity universal joint according to the present invention includes an outer joint member and an inner joint member that transmits torque while allowing angular displacement between the outer joint member and the shaft joint of the inner joint member. A constant velocity universal joint in which a shaft is inserted and the inner joint member and the shaft are integrally connected through an uneven fitting structure, and a convex portion extending in the axial direction on the outer diameter surface of the shaft hole insertion portion of the shaft. The shaft hole insertion portion of the shaft is press-fitted into the shaft hole of the inner joint member, and a part of the inner diameter surface of the inner joint member is extruded and / or cut by this press-fitting to the inner diameter surface of the shaft hole of the inner joint member. By forming a concave portion that closely fits to the convex portion along the axial direction, the concave / convex fitting structure in which the entire fitting contact portion between the convex portion and the concave portion is in close contact is formed, and the axial press-fitting of the press-fitting is performed. The axial direction of the joint internal parts including the inner joint member With larger than the sliding resistance is obtained by less than the axial impact load applied to the joint inner part.

  According to the constant velocity universal joint of the present invention, when the shaft hole fitting portion of the shaft is press-fitted into the shaft hole of the inner joint member, the concave portion that fits closely to the convex portion of the shaft on the inner diameter surface of the shaft hole of the inner joint member. It can be formed along the axial direction. And since the whole fitting contact site | part of a convex part and a recessed part is closely_contact | adhering, the clearance gap which produces backlash in radial direction and the circumferential direction is not formed in this fitting structure. For this reason, the shaft and the inner joint member are integrated with a stable coupling force.

  According to the first constant velocity universal joint, the axial press-fit load is made smaller than the axial impact load applied to the joint internal parts including the inner joint member. The press-fitted state of the concave / convex fitting structure is released. At this time, the joint internal part moves to the back side of the joint due to the impact, but this movement abuts on the bottom wall of the outer joint member to be regulated, and the shaft slides in the axial direction with respect to the joint internal part. .

  According to the second constant velocity universal joint, since the axial press-fit load is made larger than the axial sliding resistance of the joint internal part including the outer joint member, the outer side of the joint internal part in a normal use state. In axial sliding within the joint member, the shaft does not slide axially relative to the joint internal parts.

  According to the third constant velocity universal joint, the axial press-fit load is made smaller than the axial impact load applied to the joint internal parts including the inner joint member, and more than the axial sliding resistance of the joint internal parts. If the impact load in the axial direction is applied, the press-fitted state of this uneven fitting structure is released, and the shaft slides in the axial direction with respect to the joint internal parts. In axial sliding within the outer joint member of the part, the shaft does not slide axially relative to the joint internal part.

  As the constant velocity universal joint of the present invention, even if it is a fixed type that allows only angular displacement between the outer joint member and the inner joint member, the angular displacement and axial displacement between the outer joint member and the inner joint member. It may be a sliding type that allows

  A plurality of the convex portions are arranged on the outer diameter surface of the shaft hole insertion portion of the shaft at a predetermined pitch along the circumferential direction, and the diameter of the arc drawn by the vertex of the convex portion is larger than the inner diameter of the shaft hole of the inner joint member. It is preferable to enlarge it. By setting in this way, when press-fitted, the convex portion can stably push out and / or cut a part of the inner diameter surface of the inner joint member, thereby improving the adhesion of the fitting contact portion. be able to.

  A plurality of the convex portions are arranged on the outer diameter surface of the shaft hole insertion portion of the shaft at a predetermined pitch along the circumferential direction, and the diameter of the arc drawn by the bottom of the concave portion provided between the convex portions adjacent in the circumferential direction is set on the inner side. You may make it smaller than the internal diameter of the shaft hole of a joint member. By setting in this way, it is easy to set to allow the shaft to slide when an axial impact load is applied.

  It is preferable to set the hardness of the convex portion higher than the hardness of the inner diameter surface of the shaft hole of the inner joint member. By setting in this way, the press-fit property of the shaft can be improved.

  This constant velocity universal joint can be used as a constant velocity universal joint for an automobile propeller shaft.

  According to the present invention, since the shaft and the inner joint member are integrated with a stable coupling force, the function as a constant velocity universal joint can be stably exhibited. Moreover, there is no need for a retaining ring or the like as a fixing device (fixing means) as in the prior art. For this reason, it is possible to reduce the number of parts and improve the assembly workability. In addition, since the retaining ring is not required, it is not necessary to provide a groove in which the retaining ring is mounted on the shaft, and the groove processing can be omitted. Further, the inner joint surface of the inner joint member has a convex shape in advance. There is no need to form a concave groove into which the part fits. For this reason, reduction of a processing process can be aimed at and cost reduction can be achieved.

  If the axial press-fit load is smaller than the axial impact load, if the axial impact load is applied, the shaft will slide in the axial direction with respect to the internal parts of the joint. Can be relaxed and absorbed. In addition, since the internal parts of the joint do not jump out of the constant velocity universal joint, there is no need to increase the diameter of the pipe member (tube shaft portion) connected to the constant velocity universal joint, and there is an advantage that the application is widened.

  If the axial press-fit load is greater than the axial sliding resistance of the internal parts of the joint, the shaft will not slide axially relative to the internal parts of the joint under normal operating conditions. High-precision function as a dynamic constant velocity universal joint).

  A more stable fitting state can be maintained by setting the diameter of the arc drawn by the apex of the convex portion to be larger than the inner diameter of the inner joint member and improving the adhesion at the fitting contact portion. In addition, by making the diameter of the circular arc drawn by the bottom of the concave portion provided between the convex portions adjacent in the circumferential direction smaller than the inner diameter of the shaft hole of the inner joint member, the shaft can be slid when an axial impact load is applied. This makes it easy to set up, and can stably exhibit relaxation absorption when an axial impact load is applied.

  By setting the hardness of the convex portion higher than the hardness of the inner diameter surface of the shaft hole of the inner joint member, the shaft can be easily press-fitted and the assemblability can be improved.

  Thus, the constant velocity universal joint of the present invention is most suitable as a constant velocity universal joint for a propeller shaft of an automobile.

It is sectional drawing of the constant velocity universal joint of this invention. FIG. 2 is an explanatory diagram of a relationship between an inner joint member and a shaft of the constant velocity universal joint illustrated in FIG. 1. It is principal part sectional drawing of the constant velocity universal joint shown in the said FIG. It is the XX sectional view taken on the line of FIG. It is the YY sectional view taken on the line of the said FIG. FIG. 4 is a sectional view taken along the line ZZ in FIG. 3. It is a principal part expanded sectional view of the said FIG. The shaft is inserted into the inner joint member, (a) is a sectional view when no axial sliding resistance is generated, and (b) is when axial sliding resistance is generated FIG. The shaft is inserted in the inner joint member, (a) is a sectional view when no axial impact load is applied, and (b) is a sectional view when an axial impact load is applied. FIG. The joint internal component is shown in a state where an axial impact load is applied, (a) is a sectional view of the joint internal component reaching the bottom wall of the outer joint member, and (b) is a joint internal component of the shaft. It is sectional drawing of the state remove | deviated from the spline.

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

  The constant velocity universal joint of the embodiment shown in FIG. 1 is a double offset type sliding type constant velocity universal joint, and an outer joint member 3 in which a plurality of track grooves 2 extending in the axial direction are formed on a cylindrical inner peripheral surface 1. And an inner joint member 6 in which a plurality of track grooves 5 extending in the axial direction are formed on the spherical outer peripheral surface 4, and a torque transmission member 7 that transmits torque by being interposed between the outer joint member 3 and the inner joint member 6. With. In this case, the torque transmission member 7 is a plurality of torque transmission balls 7 a each incorporated in a ball track formed by a pair of the track groove 2 of the outer joint member 3 and the track groove 5 of the inner joint member 6. The torque transmission ball 7 a is held in the pocket 8 of the cage 9.

  The center of curvature O1 of the spherical outer peripheral surface 9a of the cage 9 and the center of curvature O2 of the spherical inner peripheral surface 9b are offset by an equal distance in the opposite directions in the axial direction across the joint center O. In addition, a ring body (O-ring) 15 is attached to the inner peripheral surface opening end of the outer joint member 3 to prevent the joint internal component S (the inner joint member 6, the cage 9, the ball 7a, etc.) from coming off. .

  Further, the shaft hole insertion portion 11 a of the shaft 11 is inserted into the shaft hole 6 a (see FIGS. 2 and 4) of the inner joint member 6. And this inner joint member 6 and the shaft hole insertion part 11a of the shaft 11 are integrated via the uneven | corrugated fitting structure M. As shown in FIG.

  The opening of the outer joint member 3 is closed by the sealing device 20. It comprises a boot 22 made of a flexible material such as a rubber material or a resin material, and a metal adapter 23. The boot 22 includes a large-diameter portion 22a, a small-diameter portion 22b, and a bent portion 22c having a substantially U-shaped cross section that connects the large-diameter portion 22a and the small-diameter portion 22b. The adapter 23 has a substantially cylindrical shape, one end 23 a is press-fitted into the outer peripheral surface 29 of the outer joint member 3, and the other end 23 b holds the large-diameter portion 22 a of the boot 22 by crimping.

  Further, the boot 22 has a small-diameter portion 22 b that is externally fitted to the boot mounting portion 11 b of the shaft 11 and is fastened by a boot band 24. In this case, one end portion 23a of the adapter 23 is formed with a large diameter, and a radial wall portion 23d is formed between the one end portion 23a and the intermediate body portion 23c. The radial wall portion 23 d is in contact with the end surface 3 a on the shaft protruding side of the outer joint member 3.

  A circumferential groove 25 is provided on the outer peripheral surface of the end portion of the outer joint member 3, and an O-ring 26 as a seal ring is attached to the circumferential groove 25. Further, on the side opposite to the opening side of the circumferential groove 25 (the joint back side), a fitting concave groove into which a reduced diameter portion 27 formed by crimping the anti-boot side end portion of the boot adapter 23 toward the inner diameter side is fitted. 28 is formed.

  A window portion 51 is provided on the bottom wall 30 of the outer joint member 3, and the window portion 51 is closed with a cap 52. In this case, the cap 52 includes a disk-shaped main body 52a and a peripheral wall 52b extending axially outward from the outer peripheral edge of the main body 52a. Moreover, the window part 51 consists of the small diameter part 51a inside a coupling, and the large diameter part 51b outside a coupling. The cap 52 is attached to the window portion 51 of the bottom wall 30 of the outer joint member 3 by press-fitting the peripheral wall portion 52 b of the cap 52 into the large diameter portion 51 b of the window portion 51. In this press-fitted state, the outer peripheral edge portion of the main body portion 52 a of the cap 52 is in contact with the step portion of the window portion 51.

  Further, a pipe shaft portion 55 is connected to the outer joint member 3. That is, the short cylindrical portion 56 protrudes from the bottom wall 30 of the outer joint member 3, and the tube shaft portion 55 is joined to the short cylindrical portion 56. For joining the short cylindrical portion 56 and the tube shaft portion 55, friction joining is used. Friction welding is a technique in which members (metals and ceramics) to be joined are joined together at high speed, the members are melted or softened by frictional heat generated at that time, and then pressure is applied to join them. For this reason, the inner diameter side curl portion 57 a and the outer diameter side curl portion 57 b are formed in the joint portion 57. The inner diameter side curl portion 57 a is set to have an inner diameter larger than the inner diameter of the large diameter portion 51 b of the window portion 51, and the outer diameter of the outer diameter side curl portion 57 b is set to be smaller than the outer diameter of the outer joint member 3. ing.

  As shown in FIGS. 5 to 7 and the like, the uneven fitting structure M includes, for example, a protruding portion 31 provided in the shaft hole insertion portion 11a of the shaft 11 and an axial hole 6a of the inner joint member 6. It consists of a recess 32 formed in the inner diameter surface 45, and the entire fitting contact portion 33 between the projection 31 in the shaft 11 and the recess 32 fitted into the projection 31 is in close contact. That is, the convex part 31 and the concave part 32 fitted to this are tight-fitted over the entire circumference.

  In this case, each convex portion 31 has a triangular shape (mountain shape) having a convex round-shaped apex in the cross section, and is in the range H from the fitting contact portion (recessed portion fitting portion) 33, and has a mountain shape in the cross section. It is the range from the mid-abdomen to the summit.

  By the way, as shown in FIG. 2 and FIG. 5, the spline 35 which consists of a convex tooth and a concave tooth along an axial direction is formed. And the convex tooth of the spline 35 is hardened, and this convex tooth becomes the convex part 31 of the concave-convex fitting structure M. As this thermosetting treatment, various heat treatments such as induction hardening and carburizing and quenching can be employed. Here, induction hardening is a hardening method that applies the principle of heating a conductive object by placing Joule heat in a coil through which high-frequency current flows, and generating Joule heat by electromagnetic induction. is there. In addition, carburizing and quenching is a method in which carbon is infiltrated / diffused from the surface of a low carbon material and then quenched.

  On the inner diameter surface 45 side of the inner joint member 6, an uncured portion (unbaked state) in which no thermosetting treatment is performed. The hardness difference between the convex portion 31 and the uncured portion of the inner joint member 6 is, for example, 20 points or more in HRC. More specifically, the hardness of the surface of the convex portion 31 is set to about 50 HRC to 65 HRC, and the hardness of the uncured portion is set to about 10 HRC to about 30 HRC.

  At this time, the intermediate portion in the protruding direction of the convex portion 31 corresponds to the position of the concave portion forming surface (in this case, the inner diameter surface 45 of the inner joint member 6) before the concave portion is formed. That is, as shown in FIG. 2, the inner diameter dimension d of the inner diameter surface 45 of the inner joint member 6 is the maximum outer diameter of the convex portion 31, that is, the diameter of a circle connecting the tops of the convex portions 31 that are convex teeth of the spline 35. It is set to be smaller than the dimension (circumscribed circle diameter) D and larger than the diameter dimension B of the circle connecting the valley bottoms (the bottoms of the concave teeth of the spline 35) between the convex portions. That is, D <d <B. For this reason, the convex part 31 of the shaft 11 is press-fitted into the inner diameter surface 45 of the inner joint member 6 at least from the apex to the intermediate part in the protruding direction. Further, as shown in FIG. 7, a gap 42 is formed between the inner diameter surface 45 and the bottom of the concave teeth of the spline 35. The outer diameter A of the small shaft diameter portion 11c between the shaft hole insertion portion 11a and the boot mounting portion 11b is smaller than the minimum outer diameter (the diameter dimension B) of the shaft hole insertion portion 11a. Moreover, as shown in FIG. 3, when the axial length of the convex portion 31 is L1 and the axial length of the inner joint member 6 is L, L1> L is set.

  The spline 35 can be formed by various processing methods such as rolling processing, cutting processing, press processing, and drawing processing, which are known and publicly known means. Moreover, various heat processing, such as induction hardening and carburizing hardening, can be employ | adopted as a thermosetting process. The press-fitting start end surface 31a (see FIG. 2) of the convex portion 31 formed by forming the spline 35 is a flat surface orthogonal to the axial direction of the shaft portion.

  Next, a method for integrating the shaft 11 and the inner joint member 6 will be described. First, the shaft center of the shaft 11 and the shaft center of the inner joint member 6 are combined. In this state, the shaft hole 6 a of the inner joint member 6 is inserted (press-fitted) into the inner joint member 6. At this time, the inner diameter dimension d of the inner diameter surface 45 of the shaft hole 6a of the inner joint member 6, the diameter dimension D of the convex portion 31, and the diameter dimension B of the concave teeth of the spline 35 are as described above. Since the hardness of the convex portion 31 is 20 points or more larger than the hardness of the inner diameter surface 45 of the shaft hole 6a of the inner joint member 6, if the shaft 11 is press-fitted into the shaft hole 6a of the inner joint member 6, the convex portion 31 bites into the inner diameter surface 45 of the inner joint member 6, and the convex portion 31 forms a concave portion 32 into which the convex portion 31 is fitted along the axial direction.

  By the way, when the axial length of the convex portion 31 is L1 and the axial length of the inner joint member 6 is L, L1> L is set. For this reason, as shown in FIG. 3, the press-fitting is performed until the tip of the convex portion 31 (the press-fitting start end face 31 a) slightly protrudes from the end face 40 on the joint back side of the inner joint member 6. In this state, the base end of the convex portion 31 is slightly protruded from the end surface 41 on the joint opening side of the inner joint member 6.

  As a result, as shown in FIG. 7, the entire fitting contact portion 33 between the convex portion 31 of the shaft 11 and the concave portion 32 fitted therein is in close contact. That is, the shape of the convex portion 31 is transferred to the concave-part-forming surface on the other side (in this case, the inner diameter surface 45 of the shaft hole 6a of the inner joint member 6). At this time, as the convex portion 31 bites into the inner diameter surface 45, the shaft hole 6 a of the inner joint member 6 is slightly expanded in diameter, and the axial movement of the convex portion 31 is allowed. If the movement stops, the diameter of the shaft hole 6a is reduced to return to the original diameter. In other words, when the convex portion 31 is press-fitted, the shaft hole 6a is elastically deformed in the radial direction, and a preload corresponding to the elastic deformation is applied to the tooth surface of the convex portion 31 (surface of the concave portion fitting portion). For this reason, the concave / convex fitting structure M in which the entire concave portion fitting portion of the convex portion 31 is in close contact with the corresponding concave portion 32 can be reliably formed. That is, a female spline 36 that is in close contact with the male spline 35 is formed on the inner diameter surface 45 of the shaft hole 6 a of the inner joint member 6 by the spline (male spline) 35 of the shaft 11.

  In addition, if the shaft 11 is press-fitted, a protruding portion is formed. Here, the protruding portion is the material of the capacity of the concave portion 32 into which the convex portion 31 is fitted (fitted), and is extruded from the formed concave portion 32 and cut to form the concave portion 32. It is comprised from what was extruded, what was extruded, and what was cut. For this reason, it is preferable to remove the protruding portion after press-fitting.

  The axial press-fitting load of the press-fitting is made larger than the axial sliding resistance of the joint internal part S (the inner joint member 6, the cage 9, the ball 7a, etc.) housed in the outer joint member 3. Here, the axial sliding resistance is a resistance when the joint internal component S slides relatively in the joint axial direction as indicated by an arrow X1 in FIG. is there. FIG. 8A shows a state where no axial sliding resistance is generated. Incidentally, the axial press-fit load is determined based on the relationship of D <d <B, the hardness difference between the convex portion 31 of the shaft 11 and the inner surface 45 of the inner joint member 6, and the like.

  By setting in this way, even if axial sliding resistance occurs, the joint internal component S does not deviate from the shaft hole insertion portion 11a of the shaft 11 as shown in FIG.

  Further, the press-fitting load of the press-fitting is set smaller than the axial impact load applied to the joint internal part S. Here, the axial impact load is, for example, one end face 40 of the inner joint member 6 as shown by an arrow in FIG. 9A when a vehicle or the like using the constant velocity universal joint collides. The pressing force X2 acting on the.

  For this reason, as shown in FIG. 9A, in the state where the shaft hole insertion portion 11a of the shaft 11 is fixed to the inner joint member 6 via the concave-convex fitting structure M, the axial impact load is applied to the inner joint member 6. 9 is loaded, the inner joint member 6 is displaced from the shaft hole insertion portion 11a of the shaft 11 in the direction of the arrow X2, as shown in FIG. 9B.

  Next, a case where an axial impact load is applied in the assembled state will be described. In this case, a load in the direction of the arrow X3 is applied to the shaft 11 in a state where the outer joint member 3 cannot move in the axial direction. As a result, as shown in FIG. 10A, the joint internal component S moves (slides) in the outer joint member 3 in the direction of the arrow X3. Then, the cage 9 comes into contact with the inner surface of the bottom wall 30 of the outer joint member 3, and the sliding in the direction of the arrow X3 stops.

  When the pressing force in the direction of the arrow X3 further acts from this state, the axial impact load of X2 is applied to the joint internal component S as a reaction force from the bottom wall 30 of the outer joint member 3. At this time, as described above, since the press-fitting load of press-fitting is set smaller than the axial impact load applied to the joint internal part S, as shown in FIG. The fitting portion 11a protrudes toward the tube shaft portion 55 side. As a result, the axial impact load can be relaxed and absorbed.

  In the present invention, since the shaft 11 and the inner joint member 6 are integrated with a stable coupling force, the function as a constant velocity universal joint can be stably exhibited. Moreover, there is no need for a retaining ring or the like as a fixing device (fixing means) as in the prior art. For this reason, it is possible to reduce the number of parts and improve the assembly workability. Further, since no retaining ring is required, it is not necessary to provide a groove in which the retaining ring is mounted on the shaft, so that the groove processing can be omitted, and the inner diameter surface 45 of the inner joint member 6 is preliminarily provided. There is no need to form a concave groove into which the convex portion 31 is fitted. For this reason, reduction of a processing process can be aimed at and cost reduction can be achieved.

  Since the axial press-fit load is made smaller than the axial impact load, if an axial impact load is applied, the shaft 11 slides in the axial direction with respect to the joint internal part S, and this axial impact The load can be relaxed and absorbed. In addition, since the joint internal part S does not jump out of the constant velocity universal joint, there is no need to increase the diameter of the pipe member (tube shaft portion) connected to the constant velocity universal joint, and there is an advantage that the application is widened.

  Since the axial press-fit load is larger than the axial sliding resistance of the joint internal part S, the shaft 11 does not slide in the axial direction with respect to the joint internal part S in a normal use state, and the constant velocity universal joint As a (sliding type constant velocity universal joint), a highly accurate function can be exhibited.

  A more stable fitting state can be maintained by setting the diameter of the arc drawn by the apex of the convex portion 31 to be larger than the inner diameter of the inner joint member 6 and improving the adhesion of the fitting contact portion. Further, by making the diameter of the arc drawn by the bottom of the concave portion 32 provided between the convex portions 31 and 31 adjacent in the circumferential direction smaller than the inner diameter of the shaft hole 6a of the inner joint member 6, an axial impact load is applied. It is easy to set to allow the shaft 11 to slide, and it is possible to stably exhibit relaxation absorption when the axial impact load is applied.

  By setting the hardness of the convex portion 31 higher than the hardness of the inner diameter surface 45 of the shaft hole 6a of the inner joint member 6, the shaft 11 can be easily press-fitted and the assemblability can be improved.

  Thus, the constant velocity universal joint of the present invention is most suitable as a constant velocity universal joint for a propeller shaft of an automobile.

  By the way, in the said embodiment, although it was a double offset type sliding type constant velocity universal joint, a tripod type sliding type constant velocity universal joint may be sufficient. Here, the tripod type sliding type constant velocity universal joint includes an outer joint member provided with three track grooves extending in the axial direction on the inner periphery and provided with roller guide surfaces facing each other on the inner side wall of each track groove. And a tripod member having three leg shafts, and a roller member as a torque transmission member rotatably supported by the leg shafts. Further, the roller member as the torque transmission member may be a single roller type or a double roller type of an inner roller and an outer roller.

  Furthermore, it may be a fixed type constant velocity universal joint using a ball for a barfield type or undercut free type torque transmission member. Such a fixed type constant velocity universal joint has an outer joint member in which a plurality of track grooves are formed on the inner spherical surface along the axial direction at equal intervals in the circumferential direction, and a track groove of the outer joint member is paired on the outer spherical surface. A plurality of track grooves formed between the inner joint member formed along the axial direction at equal intervals in the circumferential direction, and a plurality of torque grooves interposed between the track grooves of the outer joint member and the track grooves of the inner joint member. And a cage for holding the ball interposed between the inner spherical surface of the outer joint member and the outer spherical surface of the inner joint member. In the bar field type, the track groove bottom has only an arc portion, and in the undercut free type, the track groove bottom has an arc portion and a straight portion.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications are possible. However, various shapes such as other trapezoidal shapes, semicircular shapes, semielliptical shapes, rectangular shapes, etc. can be adopted, and the area, number, circumferential arrangement pitch, etc. of the convex portions 31 can be arbitrarily changed. . That is, it is not necessary to form the spline 35 and use the convex teeth of the spline 35 as the convex portion 31 of the concave-convex fitting structure M, and it may be a key, and a curved corrugated mating surface may be used. It may be formed. The point is that the convex portion 31 disposed along the axial direction can be press-fitted into the mating side, and the concave portion 32 can be formed on the mating side with the convex portion 31 so as to closely fit the convex portion 31. The entire fitting contact portion 33 between the portion 31 and the concave portion 32 fitted thereto may be in close contact.

  Since only the press-fitting start end portion of the convex portion 31 only needs to be harder than the portion where the concave portion 32 is formed, it is not necessary to increase the overall hardness of the convex portion 31. Moreover, in the said embodiment, in the uneven | corrugated fitting structure M, as shown in FIG. 4, although the clearance gap 42 is formed between the convex parts 31 and 31 adjacent to the circumferential direction, the convex part 31 whole bites in and a clearance gap is formed. 42 may be eliminated. In addition, as a hardness difference between the convex portion 31 side and the concave portion forming surface side formed on the convex portion 31 (inner diameter surface 45 side of the inner joint member 6), it is preferable that the HRC is 20 points or more, If the convex part 31 can be press-fitted, it may be less than 20 points.

  Although the end surface (press-fit start end) of the convex portion 31 is a surface orthogonal to the axial direction in the embodiment, it may be inclined at a predetermined angle with respect to the axial direction. In this case, it may be inclined from the inner diameter side toward the outer diameter side toward the anti-convex portion side or inclined toward the convex portion side. Moreover, when press-fitting, even if the inner joint member 6 side is fixed and the shaft 11 side is moved, the inner joint member 6 is fixed so that the shaft 11 side is fixed and the inner joint member 6 side is moved. And the shaft 11 may be moved.

  Furthermore, you may provide the small recessed part arrange | positioned in the internal diameter surface 45 with a predetermined pitch along the circumferential direction. The small recess needs to be smaller than the volume of the recess 32. Thus, by providing a small recessed part, the press-fit property of the convex part 31 can be aimed at. That is, by providing the small concave portion, the capacity of the protruding portion formed when the convex portion 31 is press-fitted can be reduced, and the press-fit resistance can be reduced. Various shapes such as a semi-elliptical shape and a rectangular shape can be adopted as the shape of the small concave portion, and the number can be arbitrarily set.

  The application is not limited to the propeller shaft, and it can be used for other various industrial machines.

3 Outer joint member 6 Inner joint member 6a Shaft hole 11 Shaft 11a Shaft hole fitting part 31 Convex part 32 Concave part Concavity and convexity fitting structure S Joint internal part

Claims (9)

An outer joint member and an inner joint member that transmits torque while allowing angular displacement between the outer joint member, and a shaft is fitted into the shaft hole of the inner joint member. It is a constant velocity universal joint that is integrally connected through an uneven fitting structure,
A convex portion extending in the axial direction is provided on the outer diameter surface of the shaft hole insertion portion of the shaft, and the shaft hole insertion portion of the shaft is press-fitted into the shaft hole of the inner joint member, and this press-fitting causes a part of the inner diameter surface of the inner joint member. Is formed by extruding and / or cutting the inner joint surface of the inner joint member so that the convex portion is in close contact with the convex portion along the axial direction. The constant velocity freedom is characterized in that it constitutes the concave-convex fitting structure, and the axial press-fitting load of the press-fitting is smaller than the axial impact load applied to the joint internal parts housed in the outer joint member. Fittings. An outer joint member and an inner joint member that transmits torque while allowing angular displacement between the outer joint member, and a shaft is fitted into the shaft hole of the inner joint member. It is a constant velocity universal joint that is integrally connected through an uneven fitting structure,
A convex portion extending in the axial direction is provided on the outer diameter surface of the shaft hole insertion portion of the shaft, and the shaft hole insertion portion of the shaft is press-fitted into the shaft hole of the inner joint member, and this press-fitting causes a part of the inner diameter surface of the inner joint member. Is formed by extruding and / or cutting the inner joint surface of the inner joint member so that the convex portion is in close contact with the convex portion along the axial direction. A constant velocity universal joint comprising the concave-convex fitting structure and having an axial press-fitting load of the press-fitting greater than an axial sliding resistance of a joint internal component housed in an outer joint member. An outer joint member and an inner joint member that transmits torque while allowing angular displacement between the outer joint member, and a shaft is fitted into the shaft hole of the inner joint member. It is a constant velocity universal joint that is integrally connected through an uneven fitting structure,
A convex portion extending in the axial direction is provided on the outer diameter surface of the shaft hole insertion portion of the shaft, and the shaft hole insertion portion of the shaft is press-fitted into the shaft hole of the inner joint member, and this press-fitting causes a part of the inner diameter surface of the inner joint member. Is formed by extruding and / or cutting the inner joint surface of the inner joint member so that the convex portion is closely fitted to the convex portion along the axial direction. And the axial press-fitting load of the press-fitting is made larger than the axial sliding resistance of the joint internal component housed in the outer joint member, and the load is applied to the joint internal component. The constant velocity universal joint is characterized by being smaller than the axial impact load.   The constant velocity universal joint according to claim 1, wherein the constant velocity universal joint is a fixed type that allows only an angular displacement between the outer joint member and the inner joint member.   The constant velocity universal joint according to any one of claims 1 to 3, wherein the constant velocity universal joint is of a sliding type that allows angular displacement and axial displacement between the outer joint member and the inner joint member.   A plurality of the convex portions are arranged on the outer diameter surface of the shaft hole insertion portion of the shaft at a predetermined pitch along the circumferential direction, and the diameter of the arc drawn by the vertex of the convex portion is larger than the inner diameter of the shaft hole of the inner joint member. The constant velocity universal joint according to any one of claims 1 to 5, wherein the constant velocity universal joint is increased.   A plurality of the convex portions are arranged on the outer diameter surface of the shaft hole insertion portion of the shaft at a predetermined pitch along the circumferential direction, and the diameter of the arc drawn by the bottom of the concave portion provided between the convex portions adjacent in the circumferential direction is set on the inner side. The constant velocity universal joint according to any one of claims 1 to 6, wherein the constant velocity universal joint is smaller than an inner diameter of a shaft hole of the joint member.   The constant velocity universal joint according to any one of claims 1 to 7, wherein the hardness of the convex portion is set to be higher than the hardness of the inner diameter surface of the shaft hole of the inner joint member.   The constant velocity universal joint according to any one of claims 1 to 8, wherein the constant velocity universal joint is used for a constant velocity universal joint for a propeller shaft of an automobile.

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