JP2008190594A - Ball type constant velocity joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball type constant velocity joint enabling to prevent the removal of a boot from an outer ring while being miniaturized. <P>SOLUTION: The outer ring 20 as part of the ball type constant velocity joint 10 has an annular groove 25 formed in the inner peripheral face at the side of an opening portion of the outer ring 20 beyond an outer ring ball groove 23 in the peripheral direction. The boot 70 has an annular protrusion 76 protruded from the outer peripheral face outward in the radial direction for engaging with the annular groove 25. The ball type constant velocity joint 10 has a thrust member 80 for thrusting the inner peripheral face of the boot 70 corresponding to the annular protrusion 76 outward in the radial direction. The thrust member 80 thrusts the boot 70 outward in the radial direction, whereby the annular protrusion 76 firmly engages with the annular groove 25 of the outer ring 20 to prevent the removal of the boot 70 form the outer ring 20. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a ball-type constant velocity joint.

In the conventional ball-type constant velocity joint, the boot is attached to the outer peripheral surface of the outer ring. Therefore, the maximum outer diameter of the constant velocity joint is obtained by adding the thickness of the boot in addition to the outer diameter of the outer ring. Therefore, in order to reduce the maximum outer diameter, for example, there is one described in Japanese Patent Laid-Open No. 2001-304285 (Patent Document 1). In the ball-type constant velocity joint described in Patent Document 1, the large-diameter end of the boot is press-fitted into the opening side of the inner peripheral surface of the outer ring. Thus, according to the constant velocity joint described in Patent Document 1, the maximum outer diameter is the outer diameter of the outer ring, and the diameter of the boot can be reduced.
JP 2001-304285 A

  By the way, the boot covers the space between the outer ring and the shaft to seal the inside of the outer ring. The sealed space is filled with grease. This boot is required to maintain a state in which the inside of the outer ring is sealed even when the joint angle is taken. Here, as described above, the constant velocity joint described in Patent Document 1 press-fits the large-diameter side end of the boot into the opening side of the inner peripheral surface of the outer ring. However, if the boot is attached to the inner peripheral side of the outer ring by press-fitting, the boot may be detached from the outer ring. In particular, when the joint angle is large, the boot may be detached from the outer ring at a portion of the boot where the axial tensile force acts. When the boot is detached from the outer ring, there is a problem that grease filled inside leaks to the outside.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a ball-type constant velocity joint capable of preventing the boot from being detached from the outer ring while reducing the size.

  The ball-shaped constant velocity joint of the present invention has a cylindrical shape having an opening at least at one end, and is arranged on the inner surface of the outer ring having a plurality of outer ring ball grooves, on the inner side of the outer ring, and on the outer circumferential surface. The inner ring in which the inner ring ball groove is formed, the outer ring ball grooves and the plurality of balls arranged to be able to roll in engagement with the inner ring ball grooves in the circumferential direction, and the inner ring side of the inner ring are connected. And a cylindrical boot that covers the space between the opening of the outer ring and the shaft. Furthermore, the outer ring is formed with an annular groove in the circumferential direction on the opening side of the outer ring ball groove on the inner circumferential surface. The boot includes an annular protrusion that protrudes radially outward from the outer peripheral surface thereof and engages with the annular groove. Furthermore, the ball-shaped constant velocity joint of the present invention includes a pressing member that presses the inner peripheral surface of the boot corresponding to the annular protrusion outward in the radial direction.

  According to the present invention, the annular protrusion formed on the outer peripheral surface of the boot is engaged with the annular groove formed on the inner peripheral surface of the outer ring. That is, one end of the boot is inserted into the inner peripheral surface of the outer ring. Therefore, by positioning the one end of the boot on the inner peripheral side of the outer ring, the ball-type constant velocity joint can be reduced in size as compared with the case where the one end of the boot is attached to the outer peripheral surface of the outer ring. Furthermore, the engagement of the annular groove of the outer ring and the annular protrusion of the boot can prevent the boot from being easily detached from the outer ring. Further, the pressing member presses the inner peripheral surface of the boot corresponding to the annular protrusion outward in the radial direction. Thereby, the annular protrusion and the annular groove are more firmly engaged, and the annular protrusion can be further prevented from being detached from the annular groove. As described above, since the boot can be further prevented from being detached from the outer ring, it is possible to prevent the grease filled inside from leaking to the outside.

  The pressing member may be in contact with the ball when the ball is positioned at the end of the outer ring ball groove. This restricts the ball from moving toward the opening of the outer ring from the end of the outer ring ball groove. In other words, the pressing member has a function as a stopper in addition to preventing the above-described boot from being detached from the outer ring. Therefore, it is possible to prevent the balls from coming off when the ball-shaped constant velocity joint is assembled and when the ball-shaped constant velocity joint after assembly is conveyed.

  The pressing member abuts against the ball when the ball is positioned at the end of the outer ring ball groove, and a portion of the pressing member that abuts on the ball is pressed radially outward by the ball. May be. In this way, the pressing member is pressed radially outward by the ball, whereby the engaging force between the annular protrusion and the annular groove can be further increased. Here, the portion of the pressing member that comes into contact with the ball corresponds to the portion of the boot where the axial tensile force acts when the joint angle is large. The axial tensile force acting on the boot is a force for separating the boot from the outer ring. That is, according to the present invention, the engagement force between the annular protrusion and the annular groove is further increased at the portion where the axial tensile force acts in the boot, so that the boot can be more reliably prevented from being detached from the outer ring.

  Here, it has been described that when the pressing member comes into contact with the ball, the pressing member has a function as a stopper. However, when the pressing member is in contact with the ball and the pressing member is pressed radially outward by the ball, the pressing member may have a function as a stopper or a function as a stopper. May not be included. Of course, it is better that the pressing member is pressed radially outward by the ball and has a function as a stopper.

  Here, in the above description, it has been described that the pressing member contacts the ball when the ball is positioned at the end of the outer ring ball groove. In addition, when the ball is positioned at the end of the outer ring ball groove, the end of the boot may abut against the ball. In this case, the end of the boot has a function as a ball stopper. That is, when the end of the boot comes into contact with the ball, the ball is restricted from moving toward the opening of the outer ring rather than the end of the outer ring ball groove. Therefore, it is possible to prevent the balls from coming off when the ball-shaped constant velocity joint is assembled and when the ball-shaped constant velocity joint after assembly is conveyed.

  Further, the end of the boot contacts the ball when the ball is positioned at the end of the outer ring ball groove, and the portion of the boot that contacts the ball is sandwiched between the ball and the outer ring. Also good. As described above, the portion of the boot that contacts the ball is sandwiched between the ball and the outer ring, so that the boot can be further prevented from being detached from the outer ring. In particular, the portion of the boot that contacts the ball corresponds to the portion of the boot on which an axial tensile force acts when the joint angle is large. That is, the end of the boot is sandwiched between the ball and the outer ring at a portion of the boot where the axial tensile force acts. Therefore, it is possible to more reliably prevent the boot from being detached from the outer ring.

  Here, in the above description, it has been described that the end portion of the boot has a function as a stopper when the end portion of the boot comes into contact with the ball. However, when the end of the boot is in contact with the ball and the end of the boot is sandwiched between the ball and the outer ring, the end of the boot may have a function as a stopper, It is also possible not to have a function as a stopper. Of course, it is better that the end of the boot is sandwiched between the ball and the outer ring and has a function as a stopper.

  The pressing member may be formed in an annular shape that can be reduced in diameter. Here, the boot covers the opening of the outer ring and the outer peripheral surface of the shaft. Therefore, after attaching the boot to the outer ring and the shaft, it is not easy to attach the pressing member to the inner peripheral surface of the boot. Therefore, it is conceivable to arrange the pressing member on the inner peripheral surface of the boot before attaching the boot to the outer ring. By the way, the inner diameter of the open end of the outer ring is smaller than the outer diameter of the annular protrusion of the boot. Therefore, in order to engage the annular protrusion of the boot with the annular groove of the outer ring, the diameter of the annular protrusion of the boot is reduced. Since the pressing member is arranged on the inner peripheral surface of the boot in advance, the pressing member needs to be deformed according to the deformation of the annular protrusion of the boot. Here, according to the present invention, as described above, the pressing member has an annular shape that can be reduced in diameter. Therefore, the pressing member can be reduced in diameter according to the reduction in diameter of the annular protrusion of the boot. Thereby, a boot can be inserted in the inner peripheral side of an outer ring | wheel in the state which has previously arrange | positioned the press member to the inner peripheral surface of a boot. When the annular protrusion of the boot engages with the annular groove of the outer ring, the pressing member expands in diameter and presses the annular protrusion of the boot toward the outer peripheral side. In this way, the pressing member can be reliably assembled.

  Moreover, as a 1st example, when a press member consists of a ring which can be diameter-reduced, as for a press member, the slit which has a cut surface parallel to the surface inclined with respect to the cyclic | annular radial direction cut surface is formed. It may be. In this case, when the pressing member receives a force from the radially outer side toward the radially inward side, the one end having the cut surface of the slit moves so as to be shifted radially inward of the other end. Thereby, the diameter of the pressing member is reduced. Thus, the diameter of the pressing member can be reliably reduced by forming the slit.

  As a second example, the pressing member may be a coil spring. Thereby, the diameter of the pressing member can be reliably reduced. Furthermore, since the pressing member is made of a coil spring, the pressing member can reliably press the boot radially outward over the entire circumference.

  Also, the inner diameter of the outer ring on the opening side of the annular groove is preferably formed so as to increase in diameter toward the end of the opening. Thereby, it becomes easy to insert the boot into the inner peripheral side of the outer ring. That is, the assembling property is good. Furthermore, in this case, the opening side located on the outer ring side of the boot on the axial end surface of the annular protrusion may be formed so as to decrease in diameter toward the opening side. This further facilitates insertion of the boot into the inner peripheral side of the outer ring.

  According to the ball-shaped constant velocity joint of the present invention, it is possible to prevent the boot from being detached from the outer ring while reducing the size.

  Next, the present invention will be described in more detail with reference to embodiments. In this embodiment, a Zepper type constant velocity joint, which is a fixed ball type constant velocity joint, will be described as an example of the ball type constant velocity joint of the present invention. However, the present invention is not limited to the Rzeppa constant velocity joint, and can be applied to, for example, a sliding ball constant velocity joint.

<First embodiment>
A configuration of the Rzeppa constant velocity joint 10 (hereinafter simply referred to as “constant velocity joint”) of the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view (axial cross-sectional view) cut in the axial direction of the constant velocity joint 10 in the case of the joint angle θ. FIG. 2 is a side view of the pressing member 80 constituting the constant velocity joint 10.

  As shown in FIG. 1, the constant velocity joint 10 includes an outer ring 20, an inner ring 30, a plurality of balls 40, a cage 50, a shaft 60, a boot 70, and a pressing member 80. Hereinafter, each component will be described in detail.

  The outer ring 20 has a cup shape (bottomed cylindrical shape) having an opening at the right end in FIG. A connecting shaft 21 is integrally formed on the outer side (left side in FIG. 1) of the outer ring 20 so as to extend in the direction of the outer ring axis. The connecting shaft 21 is connected to another power transmission shaft. Furthermore, the inner peripheral surface of the outer ring 20 is formed in a spherical concave shape. Specifically, the innermost peripheral surface 22 of the spherical concave inner peripheral surface of the outer ring 20 is formed into a uniform arc, that is, a concave partial spherical shape when viewed in a cross section cut in the outer ring axial direction.

  Further, on the spherical concave inner peripheral surface of the outer ring 20, outer ring ball grooves 23 made of a plurality of (for example, six) circular arc concaves are formed so as to extend in the outer ring axial direction. The plurality of outer ring ball grooves 23 are formed at equal intervals in the circumferential direction when viewed in a radial cross section. Here, the outer ring axial direction means a direction passing through the central axis of the outer ring 20, that is, a rotation axis direction of the outer ring 20.

  Further, an enlarged diameter portion 24 that is larger than the inner diameter of the innermost circumferential surface 22 is formed on the inner circumferential surface of the outer race 20 on the opening side of the outer race 20 with respect to the outer race ball groove 23. An annular groove 25 is formed in the enlarged diameter portion 24 over the entire circumference. The groove width of the annular groove 25 is narrowed outward in the radial direction. The groove side surfaces 25a and 25b on both sides of the annular groove 25 are both tapered. Specifically, the groove side surface 25 a on the cup bottom side of the outer ring 20 in the annular groove 25 is formed in a tapered shape that increases in diameter toward the opening side of the outer ring 20. On the other hand, the groove side surface 25 b on the opening side of the outer ring 20 in the annular groove 25 is formed in a tapered shape that decreases in diameter as it goes to the opening side of the outer ring 20. Further, the groove bottom surface 25c of the annular groove 25 is a cylindrical surface having substantially the same diameter in the axial direction.

  Further, a portion 26 located closest to the opening end of the outer ring 20 in the enlarged diameter portion 24, that is, the opening side of the outer ring 20 further than the annular groove 25 (hereinafter referred to as “the most opening end portion 26”), The outer ring 20 is formed in a tapered shape whose diameter increases toward the end of the opening. The taper angle of the most open end 26 is substantially the same as the taper angle of the groove side surface 25 a on the cup bottom side of the outer ring 20 in the annular groove 25. That is, the most open end portion 26 and the groove side surface 25 a on the cup bottom side of the outer ring 20 in the annular groove 25 are formed substantially in parallel.

  The inner ring 30 has an annular shape and is disposed inside the outer ring 20. The outer peripheral surface of the inner ring 30 is formed in a spherical convex shape. Specifically, the outermost peripheral surface 31 of the spherical convex outer peripheral surface of the inner ring 30 is formed in a uniform arc, that is, a convex partial spherical surface when viewed in a cross section cut in the inner ring axial direction. The center of the partial spherical surface of the outermost peripheral surface 31 is located on the right side of FIG. That is, the diameter on the right side in FIG. 1 of the outermost peripheral surface 31 is larger than the diameter on the left side in FIG.

  Further, on the spherical convex outer peripheral surface of the inner ring 30, an inner ring ball groove 32 made of a plurality of (for example, six) circular arc concaves is formed so as to extend in the inner ring axial direction. The plurality of inner ring ball grooves 32 are formed at equal intervals in the circumferential direction and the same number as the outer ring ball grooves 23 formed in the outer ring 20 when viewed in a cross section cut in the radial direction. That is, each inner ring ball groove 32 is positioned so as to face each outer ring ball groove 23 of the outer ring 20.

  Further, an inner peripheral spline 33 extending in the inner ring axial direction is formed on the inner peripheral surface of the inner ring 30. The inner peripheral spline 33 is fitted (engaged) with an outer peripheral spline 61 of the shaft 60 described later. Here, the inner ring axial direction means a direction passing through the central axis of the inner ring 30, that is, a rotation axis direction of the inner ring 30.

  The plurality of balls 40 are respectively disposed in the outer ring ball groove 23 of the outer ring 20 and the inner ring ball groove 32 of the inner ring 30. Each ball 40 rolls in the groove extending direction with respect to each outer ring ball groove 23 and each inner ring ball groove 32 and engages in the circumferential direction (around the outer ring axis or around the inner ring axis). Yes. Therefore, the ball 40 transmits torque between the outer ring 20 and the inner ring 30.

  The cage 50 has an annular shape. The outer peripheral surface 51 of the cage 50 is formed in a partial spherical shape substantially corresponding to the innermost peripheral surface 22 of the outer ring 20, that is, a spherical convex shape. On the other hand, the inner peripheral surface 52 of the cage 50 is formed in a partial spherical shape substantially corresponding to the outermost peripheral surface 31 of the inner ring 30, that is, a spherical concave shape. The cage 50 is disposed between the innermost circumferential surface 22 of the outer ring 20 and the outermost circumferential surface 31 of the inner ring 30. Further, the cage 50 has a plurality of substantially rectangular hole opening windows 53 formed at equal intervals in the circumferential direction (circumferential direction of the cage axis). The same number of the opening windows 53 as the balls 40 are formed. One ball 40 is accommodated in each opening window 53.

  The shaft 60 is a power transmission shaft that transmits the power of the internal combustion engine when used in, for example, an automobile. An outer peripheral spline 61 is formed on the outer peripheral surface on one end side of the shaft 60. By fitting (meshing) the outer peripheral spline 61 to the inner peripheral spline 33 of the inner ring 30, the shaft 60 is coaxially connected to the inner ring 30. At this time, of the one end side of the shaft 60, the end side (left side in FIG. 1) from the outer peripheral spline 61 is inserted into the inner side of the outer ring 20.

  The boot 70 is integrally formed in a bellows cylinder shape. The boot 70 is molded by a known molding method such as blow molding or injection molding using synthetic resin or rubber. In addition, as a synthetic resin, thermoplastic resins, such as TPE (polyester-type thermoplastic elastomer) and TPO (polyolefin-type thermoplastic elastomer), are used, for example. The boot 70 covers the space between the opening of the outer ring 20 and the shaft 60 to seal the inside of the outer ring 20. The outer ring 20 is filled with a lubricant such as grease.

  Specifically, the boot 70 includes a large-diameter cylindrical portion 71, a small-diameter cylindrical portion 72, and a bellows portion 73, which are integrally formed. The entire boot 70 is formed so as to have substantially the same thickness.

  The large-diameter cylindrical portion 71 is almost fitted into the enlarged-diameter portion 24 of the outer ring 20. The large-diameter cylindrical portion 71 includes an outer peripheral annular protrusion 76 (corresponding to an “annular protrusion” in the present invention), an annular groove 77, and a shaft protrusion 78.

  The outer peripheral annular protrusion 76 is provided to protrude outward in the radial direction on the outer peripheral surface. The outer peripheral annular protrusion 76 is formed in a shape corresponding to the annular groove 25 of the outer ring 20. That is, the protrusion width of the outer peripheral annular protrusion 76 is made narrower radially outward. The axial end faces 76a and 76b of the outer peripheral annular protrusion 76 are both tapered. Specifically, the axial end surface 76a on the left side in FIG. 1 (opening side located on the outer ring 20 side of the boot 70) of the outer peripheral annular projection 76 goes to the left side (the opening side) in FIG. It is formed in a tapered shape with a reduced diameter. On the other hand, the axial end surface 76b on the right side in FIG. 1 (the opening side located on the opposite side of the outer ring 20 of the boot 70) of the outer peripheral annular projection 76 decreases as it goes to the right side (the opening side) in FIG. It is formed in a tapered shape with a diameter. The outer diameter of the outer peripheral annular protrusion 76 is substantially equal to the inner diameter of the annular groove 25 of the outer ring 20. Further, the protrusion amount of the outer peripheral annular protrusion 76 is substantially equal to the groove depth of the annular groove 25 of the outer ring 20. The outer peripheral annular protrusion 76 is engaged with the annular groove 25 of the outer ring 20. That is, the large diameter cylindrical portion 71 is attached to the inner peripheral side of the outer ring 20.

  The annular groove 77 is formed in the inner peripheral surface of the large-diameter cylindrical portion 71 at a portion corresponding to the annular protrusion 76 (a radially inner portion) over the entire circumferential direction. The annular groove 77 is formed in a substantially semicircular arc concave shape in a cross section cut in the axial direction.

  The shaft projection 78 is provided at the opening end portion of the large-diameter cylindrical portion 71 so as to project outward in the axial direction. The shaft protrusion 78 is formed over the entire circumference in the circumferential direction. The shaft protrusion 78 is located radially inward from the annular protrusion 71. The shaft projection 78 is located on the cup bottom side of the outer ring 20 with respect to the enlarged diameter portion 24 of the outer ring 20. That is, the shaft protrusion 78 is disposed so as to contact the inner peripheral surface of the outer ring 20 between the outer ring ball groove 23 and the enlarged diameter portion 24.

  The small diameter cylindrical portion 72 has a substantially cylindrical shape having a smaller diameter than the large diameter cylindrical portion 71. The small diameter cylindrical portion 72 is fastened and fixed to the outer peripheral surface of the shaft 60 by a clamp member. The position of the shaft 60 to which the small-diameter cylindrical portion 72 is fastened and fixed is closer to the center of the shaft (right side in FIG. 1) than the position where the outer peripheral spline 61 is formed. 1 is located on the right side of FIG. 1 (outside of the outer ring 20 from the opening end of the outer ring 20).

  The bellows portion 73 is formed in a bellows cylinder shape and has elasticity in the axial direction. The bellows portion 73 is integrally provided between the large diameter cylindrical portion 71 and the small diameter cylindrical portion 72. That is, one end side (the left side in FIG. 1) of the bellows portion 73 is integrally connected to the large diameter cylindrical portion 71. On the other hand, the other end side (the right side in FIG. 1) of the bellows portion 73 is integrally connected to the small diameter cylindrical portion 72.

  The pressing member 80 is made of metal or resin and is formed in an annular shape. Here, the pressing member 80 will be described with reference to FIG. 2 in addition to FIG. That is, as shown in FIG. 1, the pressing member 80 has a circular cross section that is cut in the axial direction and has the same diameter as the annular groove 77 formed in the large-diameter cylindrical portion 71 of the boot 70. More specifically, as shown in FIG. 2, the pressing member 80 has an annular shape in which a slit 81 is formed. The slit 81 has a cut surface parallel to a surface inclined with respect to the annular radial cut surface. That is, the slit 81 has a substantially elliptical cut surface. Further, both cut surfaces of the slit 81 are formed substantially in parallel. By having such a slit 81, the pressing member 80 can be reduced in diameter.

  The pressing member 80 is fitted into an annular groove 77 formed in the large diameter cylindrical portion 71 of the boot 70. That is, the pressing member 80 presses the inner peripheral surface of the boot 70 corresponding to the annular protrusion 76 radially outward. That is, the pressing member 80 is configured to firmly engage the annular protrusion 76 with the annular groove 25 of the outer ring 20. Further, the pressing member 80 protrudes radially inward from the inner peripheral surface of the large diameter cylindrical portion 71 of the boot 70. That is, the pressing member 80 can contact the ball 40 when the joint angle is increased.

  Next, a process of assembling the boot 70 and the pressing member 80 constituting the above-described Rzeppa constant velocity joint 10 to the outer ring 20 will be described. First, before the large-diameter cylindrical portion 71 of the boot 70 is inserted into the large-diameter portion 24 of the outer ring 20, the pressing member 80 is fitted into the annular groove 77 of the large-diameter cylindrical portion 71 of the boot 70. Subsequently, the large-diameter cylindrical portion 71 of the boot 70 is inserted into the inner peripheral side of the outer ring 20 while the pressing member 80 is fitted in the annular groove 77. At this time, the left axial end surface 76 a in FIG. 1 of the outer peripheral annular protrusion 76 of the large-diameter cylindrical portion 71 comes into contact with the most open end portion 26 of the outer ring 20.

  Furthermore, when the large-diameter cylindrical portion 71 is inserted into the back side of the cup of the outer ring 20, the large-diameter cylindrical portion 71 is reduced in diameter. Here, the axial direction end surface 76a and the most opening end portion 26 are positioned substantially in parallel. Therefore, the large-diameter cylindrical portion 71 is reduced in diameter relatively easily. However, a pressing member 80 is fitted on the inner peripheral side of the large diameter cylindrical portion 71. However, the pressing member 80 can be reduced in diameter because the slit 81 is formed. Therefore, as the large diameter cylindrical portion 71 is reduced in diameter, the pressing member 80 is also reduced in diameter. That is, both the cut surfaces of the slits 81 of the pressing member 80 are shifted, and the pressing member 80 is reduced in diameter.

  When the large-diameter cylindrical portion 71 is further inserted into the back side of the cup of the outer ring 20, the large-diameter cylindrical portion 71 and the pressing member 80 are expanded in diameter, and the outer peripheral annular protrusion 76 of the large-diameter cylindrical portion 71 is The annular groove 25 is fitted and engaged. In this way, the boot 70 and the pressing member 80 are attached to the outer ring 20.

  In the state where the boot 70 and the pressing member 80 are attached to the outer ring 20, the pressing member 80 returns to the state before being reduced in diameter, and presses the large-diameter cylindrical portion 71 radially outward. That is, the pressing member 80 further strengthens the force with which the outer peripheral annular protrusion 76 of the large diameter cylindrical portion 71 engages with the annular groove 25 of the outer ring 20. In other words, the pressing member 80 can suppress the boot 70 from being detached from the outer ring 20.

  Next, the operation of the Rzeppa constant velocity joint 10 having the above-described configuration will be described. In particular, the case where the joint angle is gradually increased and the joint angle becomes the predetermined angle θ will be described. Here, when the joint angle is increased, a part of the boot 70 (the upper part in FIG. 1) is tensilely deformed. That is, the tensile force acting on the portion of the boot 70 is a force acting in the direction in which the boot 70 is detached from the outer ring 20.

  However, in this case, any of the plurality of balls 40 is located at the end of the outer ring ball groove 23. At this time, the ball 40 comes into contact with the pressing member 80. A portion of the pressing member 80 that contacts the ball 40 is pressed outward in the radial direction of the outer ring 20 by the ball 40. If it does so, the site | part which contact | abuts to the said ball | bowl 40 among the press members 80 will press the large diameter cylinder part 71 of the boot 70 to radial direction outward with a still stronger force. That is, the outer peripheral annular protrusion 76 corresponding to the portion maintains a state in which it is more firmly engaged with the annular groove 24 of the outer ring 20.

  Furthermore, when any one of the plurality of balls 40 is located at the end of the outer ring ball groove 23, the ball 40 comes into contact with the shaft protrusion 78 of the large-diameter cylindrical portion 71 of the boot 70. A portion of the shaft projection 78 that contacts the ball 40 is sandwiched between the ball 40 and the outer ring 20. If it does so, the part which contact | abuts the said ball | bowl 40 among the axial protrusions 78 will try to maintain the state clamped by the said ball | bowl 40 and the outer ring | wheel 20. FIG.

  By these actions, even if a tensile force is applied to the boot 70, the boot 70 can be reliably prevented from being detached from the outer ring 20.

  Further, when any one of the plurality of balls 40 is located at the end of the outer ring ball groove 23, the ball 40 comes into contact with the pressing member 80 and the shaft protrusion 78. This restricts the movement of the ball 40 toward the opening side of the outer ring 20 from the end of the outer ring ball groove 23. In other words, the pressing member 80 and the shaft projection 78 function as a stopper for the ball 40. Therefore, it is possible to prevent the ball 40 from being detached when the Rzeppa constant velocity joint 10 is assembled and when the Rzeppa constant velocity joint 10 is assembled.

  Further, the large-diameter cylindrical portion 71 of the boot 70 is inserted on the inner peripheral side of the outer ring 20. Therefore, the outer diameter of the constant velocity joint 10 of the present embodiment is smaller than when the large diameter cylindrical portion 71 of the boot 70 is attached to the outer peripheral side of the outer ring 20. That is, the constant velocity joint 10 of the present embodiment can achieve the above-described effects while achieving downsizing.

<Second embodiment>
Next, the Rzeppa constant velocity joint 100 (hereinafter simply referred to as “constant velocity joint”) of the second embodiment will be described with reference to FIG. FIG. 3 is a cross-sectional view (axial cross-sectional view) cut in the axial direction of the constant velocity joint 100 in the case of the joint angle θ. Here, the constant velocity joint 100 in the second embodiment is different from the constant velocity joint 10 in the first embodiment only in the boot 170 and the pressing member 180. Therefore, only the boot 170 and the pressing member 180 will be described, and the other components will be denoted by the same reference numerals and description thereof will be omitted.

  The boot 170 is composed of a large diameter cylindrical portion 171, a small diameter cylindrical portion 72, and a bellows portion 73, which are integrally formed. The large-diameter cylindrical portion 171 includes an outer peripheral annular protrusion 76, an annular groove 177, and a shaft protrusion 78. Here, since the boot 170 of the second embodiment is different from the boot 70 of the first embodiment only in the annular groove 177 of the large-diameter cylindrical portion 171, only the annular groove 177 will be described.

  The annular groove 177 is formed on the inner peripheral surface of the large-diameter cylindrical portion 171 in the portion corresponding to the annular protrusion 76 (the radially inner portion) over the entire circumference. The groove width of the annular groove 177 is substantially the same in the groove depth direction. That is, the groove bottom surface of the annular groove 177 is a cylindrical surface having substantially the same diameter in the axial direction.

  The pressing member 180 is made of a metal or resin coil spring. That is, the pressing member 180 has an annular shape that can be reduced in diameter. The axial length of the pressing member 180 is substantially equal to the groove width of the annular groove 177 of the large diameter cylindrical portion 171. Furthermore, the outer diameter of the pressing member 180 is substantially equal to the groove bottom diameter of the annular groove 177 of the large-diameter cylindrical portion 171. The pressing member 180 is fitted in the annular groove 177 of the large diameter cylindrical portion 171. That is, the pressing member 180 presses the inner peripheral surface of the boot 170 corresponding to the annular protrusion 76 radially outward. In particular, since the pressing member 180 is made of a coil spring, the inner peripheral surface of the boot 170 is reliably pressed radially outward over the entire circumference.

  According to the constant velocity joint 100 of the second embodiment, the same effect as the effect of the constant velocity joint 10 of the first embodiment is obtained. In addition, since the pressing member 180 can press the inner peripheral surface of the boot 170 radially outward over the entire circumference in the circumferential direction, the boot 170 can be further prevented from being detached from the outer ring 20.

<Third embodiment>
Next, a Rzeppa constant velocity joint 200 (hereinafter, simply referred to as “constant velocity joint”) of the third embodiment will be described with reference to FIG. FIG. 4 is a cross-sectional view (axial cross-sectional view) cut in the axial direction of the constant velocity joint 200 in the case of the joint angle θ. Here, the constant velocity joint 200 in the third embodiment is substantially different from the constant velocity joint 10 in the first embodiment only in the boot 270. Therefore, only the boot 270 will be described, and the other components will be denoted by the same reference numerals and description thereof will be omitted.

  The boot 270 is composed of a large diameter cylindrical portion 271, a small diameter cylindrical portion 72, and a bellows portion 73, which are integrally formed. The large-diameter cylindrical portion 271 includes an outer peripheral annular protrusion 76 and an annular groove 77. That is, the large diameter cylindrical portion 271 of the third embodiment has a configuration that does not include the shaft protrusion 78 in the large diameter cylindrical portion 71 of the first embodiment. In FIG. 4, the inner diameter of the annular groove 77 formed in the large-diameter cylindrical portion 271 of the boot 270 and the outer diameter of the pressing member 80 are slightly smaller than those of the first embodiment.

  In this case, although the effect by providing the axial protrusion 78 in 1st embodiment is not show | played, all the other effects are exhibited. In other words, the pressing member 80 exhibits the effect of preventing the boot 271 from being detached from the outer ring 20 and the effect of preventing the ball 40 from being detached from the outer ring ball groove 23. Here, the shaft protrusion 78 in the first embodiment exhibits substantially the same effect as the pressing member 80. That is, when the effect can be sufficiently exhibited by the pressing member 80, a configuration without the shaft protrusion 78 can be employed. And it becomes easy to form the boot 271 by setting it as the structure which is not provided with the axial protrusion 78. FIG. That is, the molding cost of the boot 271 can be reduced.

It is sectional drawing cut | disconnected in the axial direction of the constant velocity joint 10 in the case of joint angle (theta). 4 is a side view of a pressing member 80 that constitutes the constant velocity joint 10. FIG. It is sectional drawing cut | disconnected in the axial direction of the constant velocity joint 100 in the case of joint angle (theta). It is sectional drawing cut | disconnected in the axial direction of the constant velocity joint 200 in the case of joint angle (theta).

Explanation of symbols

10, 100, 200: Rzeppa constant velocity joint,
20: outer ring, 21: connecting shaft, 22: innermost circumferential surface, 23: outer ring ball groove,
24: an enlarged diameter part, 25: an annular groove, 25a, 25b: a groove side surface of the annular groove 25,
25c: groove bottom surface of the annular groove 25, 26: the most open end,
30: inner ring, 31: outermost circumferential surface, 32: inner ring ball groove, 33: inner circumferential spline,
40: Ball,
50: Cage, 51: Outer peripheral surface, 52: Inner peripheral surface, 53: Opening window,
60: Shaft 61: Perimeter spline
70, 170, 270: boots,
71, 171, 271: Large-diameter cylinder part, 72: Small-diameter cylinder part, 73: Bellows part,
76: outer peripheral annular protrusion, 76a, 76b: axial end face,
77, 177: annular groove, 78: axial projection,
80, 180: pressing member, 81: slit

Claims (10)

An outer ring having a cylindrical shape having an opening at at least one end, and having a plurality of outer ring ball grooves formed on the inner peripheral surface;
An inner ring disposed inside the outer ring and having a plurality of inner ring ball grooves formed on the outer peripheral surface;
A plurality of balls disposed in a circumferentially engaged manner with respect to each outer ring ball groove and each inner ring ball groove;
A shaft to which an inner peripheral side of the inner ring is connected;
A cylindrical boot that covers between the opening of the outer ring and the shaft;
In a ball-type constant velocity joint with
The outer ring is formed with an annular groove in the circumferential direction on the opening side from the outer ring ball groove on the inner peripheral surface,
The boot includes an annular protrusion that protrudes radially outward from the outer peripheral surface and engages with the annular groove.
A ball-type constant velocity joint, comprising a pressing member that presses an inner peripheral surface of the boot corresponding to the annular protrusion radially outward.   The ball-shaped constant velocity joint according to claim 1, wherein the pressing member abuts on the ball when the ball is positioned at an end of the outer ring ball groove. The pressing member abuts on the ball when the ball is positioned at the end of the outer ring ball groove,
The ball-shaped constant velocity joint according to claim 1, wherein a portion of the pressing member that contacts the ball is pressed outward in the radial direction by the ball.   2. The ball-type constant velocity joint according to claim 1, wherein an end of the boot abuts against the ball when the ball is positioned at an end of the outer ring ball groove. The end of the boot contacts the ball when the ball is positioned at the end of the outer ring ball groove,
The ball-shaped constant velocity joint according to claim 3, wherein a portion of the boot that contacts the ball is sandwiched between the ball and the outer ring.   The ball-shaped constant velocity joint according to any one of claims 1 to 5, wherein the pressing member has an annular shape that can be reduced in diameter.   The ball-type constant velocity joint according to claim 6, wherein the pressing member is formed with a slit having a cut surface parallel to a surface inclined with respect to the annular radial cut surface.   The ball-shaped constant velocity joint according to claim 6, wherein the pressing member is a coil spring.   The ball shape according to any one of claims 1 to 8, wherein an inner diameter of the outer ring on an opening side of the annular groove is formed so as to increase in diameter toward an end of the opening. Constant velocity joint.   The ball-shaped constant velocity joint according to claim 9, wherein an opening side of the annular protrusion, which is positioned on the outer ring side of the boot, is formed to have a diameter decreasing toward the opening side.

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