JP2008051190A - Fixed type constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize, when a ball located in a most protruding phase derails from a track groove of an outer ring at the maximum working angle, the behavior of the ball until the ball fits again in the track groove. <P>SOLUTION: The fixed type constant velocity universal joint comprises: the outer ring 10 having a plurality of track grooves 22 formed on an inner spherical surface 12; an inner ring 20 having a plurality of track grooves 27 formed on an outer spherical surface 22; a plurality of balls 27 interposed between the outer ring 25 and the inner ring 28; and a cage 30 interposed between the outer ring 25 and the inner ring 28 to hold the balls 29. The opening-side groove bottom of the track groove 22 of the outer ring 25 is tapered, and the deep-side groove bottom of the track groove 27 of the inner ring 28 is tapered. For attaining a larger angle, an interference member 60 for applying a radially inward pushing force to the ball 30 which is located in a most protruding phase and derails from the track groove 14 at the maximum working angle by shortening the track groove 14 of the outer ring 10, is disposed on an opening end bottom portion of the outer ring 10. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fixed type constant velocity universal joint, and more particularly to a fixed type constant velocity universal joint that is used in a power transmission system of an automobile or various industrial machines, and that allows only an operating angular displacement between two axes of a driving side and a driven side. It relates to a constant velocity universal joint.

  In recent years, the wheelbase may be lengthened from the viewpoint of expanding the riding space of automobiles, but in order to prevent the vehicle turning radius from increasing accordingly, the fixed type used as a coupling joint for automobile drive shafts, etc. There is a need to increase the steering angle of the front wheels by increasing the angle of the constant velocity universal joint.

  Generally, this constant velocity universal joint is an outer joint member in which a plurality of track grooves 114 are formed on an inner spherical surface 112 at equal intervals in the circumferential direction toward the opening end 118 as shown in FIG. Of the outer ring 110, an inner ring 120 as an inner joint member in which a plurality of track grooves 124 paired with the track grooves 114 of the outer ring 110 are formed on the outer spherical surface 122 along the axial direction at equal intervals in the circumferential direction, A plurality of balls 130 that transmit torque by being interposed between the track groove 114 and the track groove 124 of the inner ring 120, and a ball 130 that is interposed between the inner spherical surface 112 of the outer ring 110 and the outer spherical surface 122 of the inner ring 120. The cage 140 to hold | maintain is provided.

Since the constant velocity universal joint for the above-mentioned needs for increasing the angle has a structure capable of obtaining a large operating angle, the center of curvature O ₃ of the inner spherical surface 144 of the cage 140 and the center of curvature O of the outer spherical surface 142 are shown in FIG. ₄ is offset in the axial direction by an equal distance f with respect to the joint center plane P (cage offset). Thus, by providing the cage offset, the cage 140 has a shape that is thick toward the opening side of the outer ring 110 and thin toward the back side.

Further, the center of curvature O ₁ of the track groove 114 of the outer ring 110 and the center of curvature O ₂ of the track groove 124 of the inner ring 120 are the center of curvature O ₄ of the inner spherical surface 112 of the outer ring 110 and the center of curvature O ₃ of the outer spherical surface 122 of the inner ring 120. Is offset in the axial direction by an equal distance F (track offset). Thus, by providing the track offset, each of the track groove 114 of the outer ring 110 and the track groove 124 of the inner ring 120 is deep on the opening side of the outer ring 110 and shallow on the back side thereof. The pair of track grooves 114 and 124 form a wedge-shaped ball track in which the radial interval gradually increases from the back side of the outer ring 110 toward the opening side.

Note that the center of curvature O ₃ of the outer spherical surface 122 of the inner ring 120 coincides with the center of curvature of the inner spherical surface 144 of the cage 140, and the center of curvature O ₄ of the inner spherical surface 112 of the outer ring 110 is the center of curvature of the outer spherical surface 142 of the cage 140. Is consistent with

  In this fixed type constant velocity universal joint, in order to further increase the angle, the opening-side groove bottom of the track groove 114 of the outer ring 110 is tapered so as to linearly expand toward the opening side of the outer ring 110, and the inner ring The operation of the high angle region is realized by forming the back groove bottom of the 120 track grooves 124 into a tapered shape linearly expanding toward the back side of the inner ring 120 (for example, Patent Documents 1 to 3). reference).

  FIG. 12 shows a state in which the joint has a maximum operating angle θ, that is, the rotation axis X of the outer ring 110 and the rotation axis Y of the inner ring 120 (the central axis of the shaft 150 connected to the inner ring 120) have the maximum operating angle θ. Indicates the state. Further, in the fixed type constant velocity universal joint disclosed in Patent Document 4, the ball 130 that is in the most protruding phase (phase angle φ = 0 °) when the maximum operating angle is taken is disengaged from the track groove 114 of the outer ring 110, A structure in which the track groove 114 of the outer ring 110 is shortened within a range in which the ball 130 adjacent to the ball 130 cannot be removed from the track groove 114 of the outer ring 110 has been proposed. By adopting such a structure, interference with the shaft 150 is avoided and the angle of the joint is increased.

In the figure, the movement trajectory m of the point where the ball 130 moving in the axial direction in the track groove 114 of the outer ring 110 contacts the track groove 114 is indicated by a broken line. Further, the contact point A of the ball 130 that is out of the track groove 114 of the outer ring 110 is indicated by a cross in the figure.
JP 2001-153149 A JP 2001-304282 A JP 2001-349332 A Japanese Examined Patent Publication No. 6-68290

  By the way, in the fixed type constant velocity universal joint disclosed in the above-mentioned Patent Document 4, the track groove of the outer ring so that the contact point between the ball and the outer ring in the phase that protrudes most at the maximum operating angle is removed from the track groove of the outer ring. The structure is shortened. In this case, it is an effective means for avoiding interference with the shaft and realizing a high angle joint.

  However, once the contact point between the ball in the most protruding phase at the maximum operating angle and the track groove of the outer ring is removed from the track groove, the contact point is removed until it is accommodated in the track groove of the outer ring again. The behavior of a certain ball becomes unstable, which can cause vibration and noise.

  Therefore, the present invention has been proposed in view of the above-described problems, and the object of the present invention is to re-enter the track groove after the ball in the phase that protrudes most at the maximum operating angle is removed from the track groove of the outer ring. An object of the present invention is to provide a fixed type constant velocity universal joint with a high angle that can stabilize the behavior of the ball until it is settled.

  As technical means for achieving the above-mentioned object, the present invention includes an outer joint member in which a plurality of track grooves are formed on the inner spherical surface at equal intervals in the circumferential direction toward the opening end along the axial direction, A plurality of track grooves that are paired with the track grooves of the outer joint member, and are formed between the track grooves of the outer joint member and the inner joint member. A plurality of balls for transmitting torque, and a cage for holding the balls interposed between the inner spherical surface of the outer joint member and the outer spherical surface of the inner joint member, the outer spherical center and the inner spherical center of the cage being the joint center Is offset to the opposite side by an equal distance in the axial direction, and in the longitudinal section of the cage, the open end side of the outer joint member is made thick and the non-open end side is made thin so that the track groove of the outer joint member Open end side groove bottom toward opening end In addition, a taper shape with a linearly expanded diameter and a taper shape with the diameter of the inner joint member track groove on the side opposite to the opening end side of the track groove linearly expanded toward the side opposite to the opening end side further increase the angle. For this reason, by shortening the track groove of the outer joint member, an outer joint member is provided with an interference member that applies a pushing force toward the inner side in the radial direction with respect to the ball that protrudes most at the maximum operating angle and deviates from the track groove. The track groove is arranged at the bottom of the opening end of the track groove.

  In the present invention, the track groove of the outer joint member is shortened in order to achieve a higher angle, so that even if the ball in the phase that protrudes most at the maximum operating angle is removed from the track groove, the track groove of the outer joint member is reduced. The interference member arranged at the bottom of the open end exerts a pushing force toward the inner side in the radial direction on the ball that is in the most popping out phase, so that the behavior of the ball until it comes out of the track groove and then fits in the track groove again. Can be stabilized.

  The interference member in the configuration described above has a ring shape, and the ring-shaped interference member is inserted into an annular groove formed in a circumferential direction portion including the bottom end of the track groove of the outer joint member. desirable. In this way, the interference member can be easily disposed on the outer joint member.

  The cage having the above-described configuration has a tapered shape in which the opening end of the outer spherical surface extends in the axial direction and the opening end of the inner spherical surface of the cage expands toward the opening end of the outer spherical surface. Such a structure is desirable. Here, when the opening side end of the outer spherical surface of the cage is extended in the axial direction, the shaft attached to the inner joint member is the opening side of the cage with the constant velocity universal joint having the maximum operating angle. The opening side end of the outer spherical surface is extended to the extent that it does not interfere with the end.

  When the open end of the outer spherical surface of the cage is extended to the extent that the shaft does not interfere with the open end of the cage, the taper angle of the open end of the inner spherical surface of the cage is determined by the outer joint member and the inner joint member. It is desirable to make it more than half of the maximum operating angle. Thus, if the taper angle is set to more than half of the maximum operating angle, it is preferable in that the contact area between the outer spherical surface of the cage and the inner spherical surface of the outer joint member can be secured even in a high angle region. If this taper angle is smaller than half of the maximum operating angle, the shaft will interfere with the tapered opening side end of the cage.

  In this way, the contact area between the outer spherical surface of the cage and the inner spherical surface of the outer joint member can be ensured even in a high angle region, so that when the maximum operating angle is taken, the ball pushes the cage toward the opening side, Even if the opening-side end portion of the outer spherical surface and the inner spherical surface of the outer joint member rub against each other strongly, it is possible to minimize a decrease in durability and loss of transmission torque due to heat generation. Moreover, since the rigidity of the cage can be ensured to the maximum, the strength of the cage itself is also improved.

  In the present invention, by forming both track grooves of the outer joint member and the inner joint member into a tapered shape, it is possible to easily increase the operating angle without increasing the outer diameter of the outer joint member. In order to prevent the strength and workability of the outer joint member from being reduced even if the thickness of the member is reduced, the effects of tapering the track groove in the internal specifications of this fixed type constant velocity universal joint and The tendency was verified, and the upper limit value was defined as 12 ° as the optimum value of the taper angle of the track groove.

  The present applicant will proceed with the study using static internal force analysis and finite element method (FEM) analysis while securing strength and durability, which are the basic performance required in the past, and narrow the range of the taper angle of the track groove. Was set optimally. And the consistency with the evaluation result and analysis result of the sample which changed the taper angle was confirmed.

  In the above configuration, the cage offset amount f between the outer spherical center and the inner spherical center of the cage, and the distance PCR between the center of curvature of the track groove of the outer joint member or the center of curvature of the track groove of the inner joint member and the ball center. It is desirable that the ratio value f / PCR is 0.12 or less. Since the cage offset amount f is related to the thickness difference in the longitudinal section of the cage, it is desirable to set the cage offset amount f in consideration of this point.

  For example, if the cage offset amount f is set large so that the thick side of the cage is positioned on the opening side of the outer joint member, the thickness of the cage on the opening side of the outer joint member is increased to improve the strength. It has the advantage that can be aimed at. Further, by increasing the thickness of the cage on the opening side of the outer joint member, when the operating angle is taken, the ball that is about to jump out from the opening end of the outer joint member can be restrained by the cage.

  However, if the cage offset amount f is too large, the amount of movement of the ball in the cage pocket in the circumferential direction increases, and it is necessary to increase the circumferential dimension of the cage pocket in order to ensure proper movement of the ball. The pillar portion of the cage becomes thin, and the strength becomes a problem. Moreover, the thickness of the back side located on the opposite side to the entrance side of the cage is reduced, and the strength is a problem.

  From the above, it is not preferable that the cage offset amount f is excessive, and there exists an optimum range in which the significance of providing the cage offset amount f can be balanced with the above-described strength problem. However, since the optimum range of the cage offset amount f varies depending on the size of the joint, it needs to be determined in relation to the basic dimension representing the size of the joint. Therefore, the ratio f / PCR of the cage offset amount f and the distance PCR between the center of curvature of the track groove of the outer joint member or the center of curvature of the track groove of the inner joint member and the ball center is used.

  Therefore, the cage offset amount in the above-described configuration is the cage offset amount f and the distance PCR between the center of curvature of the track groove of the outer joint member or the center of curvature of the track groove of the inner joint member and the ball center when the operating angle is 0 °. It is desirable that the ratio f / PCR is greater than 0 and 0.12 or less.

  If this ratio f / PCR is larger than 0.12, there is a problem in the aforementioned strength. Conversely, if it is 0 or less, the significance of providing the cage offset amount f is lost. That is, when the cage offset amount f is 0, the track offset amount is also 0, so the offset becomes 0, the ball (cage) position is not determined when the wedge angle = 0, and the operability is significantly deteriorated. In range, the purpose cannot be achieved. Therefore, from the viewpoint of ensuring cage strength and durability, the optimum range of the cage offset amount f is that the ratio f / PCR is greater than 0 and 0.12 or less.

  The present invention can be applied to a fixed type constant velocity universal joint having six or eight balls. However, when applied to a fixed type constant velocity universal joint having eight balls, the fixed type constant velocity universal joint is applicable. This is effective in that the universal joint can be made compact.

  In the present invention, the track groove of the outer joint member is shortened in order to achieve a higher angle, so that the ball which is in the most popping phase at the maximum operating angle and is out of the track groove is pushed inward in the radial direction. An interference member for applying a force is provided at the bottom of the opening end of the track groove of the outer joint member.

  As a result, by shortening the track groove of the outer joint member, even if the ball in the phase that protrudes most at the maximum operating angle is detached from the track groove, the interference disposed at the bottom of the opening end of the track groove of the outer joint member. The member exerts a pushing force toward the inner side in the radial direction to the ball in the most popping phase, so that the behavior of the ball can be stabilized until it comes out of the track groove and then fits in the track groove again. And the generation of abnormal noise can be suppressed.

  As a result, it is possible to easily increase the operating angle, and in response to the desire to lengthen the wheel base from the viewpoint of expanding the riding space of automobiles in recent years, the steering angle of the front wheels has been reduced so as not to increase the vehicle turning radius. Increase can be easily achieved.

  An embodiment of a fixed type constant velocity universal joint according to the present invention will be described in detail below.

  The fixed type constant velocity universal joint shown in FIG. 1 includes an outer ring 10, an inner ring 20, a ball 30, and a cage 40 as main components. Two shafts to be connected by this fixed type constant velocity universal joint, for example, a driven rotary shaft (not shown) is connected to the outer ring 10, and a drive rotary shaft (not shown) is connected to each other. Torque is transmitted at a constant speed even in a state where 1 shows a state where the operating angle θ formed by the rotation axis X of the outer ring 10 and the rotation axis Y of the inner ring 20 (the central axis of the shaft 50 connected to the inner ring 20) is 0 °, and FIG. The state where the angle θ is maximum is shown.

  The outer ring 10 serving as an outer joint member includes a mouth portion 16 and a stem portion (not shown), and is coupled to the driven-side rotating shaft at the stem portion so that torque can be transmitted. The mouse portion 16 has a bowl shape opened at one end, and a plurality of track grooves 14 extending in the axial direction are formed on the inner spherical surface 12 at equal intervals in the circumferential direction. The track groove 14 extends to the open end 18 of the mouse portion 16.

  The inner ring 20 as an inner joint member has a plurality of track grooves 24 extending in the axial direction formed on the outer spherical surface 22 at equal intervals in the circumferential direction. The track groove 24 is cut in the axial direction of the inner ring 20. The inner ring 20 has a spline hole 26 for coupling with a drive-side rotating shaft so as to transmit torque.

  The track groove 14 of the outer ring 10 and the track groove 24 of the inner ring 20 make a pair, and a ball 30 as a torque transmitting element can roll on each ball track constituted by the pair of track grooves 14, 24. It is incorporated. The ball 30 is interposed between the track groove 14 of the outer ring 10 and the track groove 24 of the inner ring 20 to transmit torque.

  Each ball 30 is accommodated in a pocket 46 disposed in the circumferential direction of the cage 40. The number of balls 30, in other words, the number of track grooves 14, 24 is arbitrary, but 6 or 8 for example. In order to realize a compact constant velocity universal joint, eight balls are preferable as in this embodiment.

The cage 40 is slidably interposed between the outer ring 10 and the inner ring 20, is in contact with the inner spherical surface 12 of the outer ring 10 at the outer spherical surface 42, and is in contact with the outer spherical surface 22 of the inner ring 20 at the inner spherical surface 44. The center of curvature of the inner spherical surface 12 of the outer ring 10 and the center of curvature of the outer spherical surface 42 of the cage 40 coincide with each other, and are denoted by reference numeral O ₄ in FIG. Similarly, coincide with the center of curvature of the inner spherical surface 44 of the center of curvature and the cage 40 of the outer spherical surface 22 of the inner ring 20, it is indicated by reference numeral O ₃ in FIG. In the drawing, the clearance between the inner spherical surface 12 of the outer ring 10 and the outer spherical surface 42 of the cage 40 and between the outer spherical surface 22 of the inner ring 20 and the inner spherical surface 44 of the cage 40 are exaggerated.

  The track groove 14 of the outer ring 10 includes an arc portion 14a and a straight portion 14b. The arc portion 14a is located on the back side of the mouse portion 16, that is, on the side opposite to the opening, and the straight portion 14b is located on the opening end side. The track groove 14 has a taper shape with a taper angle α that linearly increases the diameter of the groove bottom on the opening end side toward the opening end 18.

  The track groove 24 of the inner ring 20 includes an arc portion 24a and a straight portion 24b. The arc portion 24a is located on the opening end side of the outer ring 10, and the straight portion 24b is located on the counter-opening end side. The track groove 24 has a tapered shape with a taper angle α that linearly expands the groove bottom on the back side of the outer ring 10, that is, on the side opposite to the opening side toward the side opposite to the opening side.

Since this joint has a structure that can take a large operating angle θ, as shown in FIG. 2, the center of curvature O ₁ of the track groove 14 of the outer ring 10 is tracked by the track of the inner ring 20 with respect to the center O ₄ of the inner spherical surface 12. The curvature center O ₂ of the groove 24 is offset in the axial direction opposite to the center O ₃ of the outer spherical surface 22 by an equal distance F (track offset). Similarly, the center of curvature O ₃ center of curvature O ₄ and the inner spherical surface 44 of the outer spherical surface 42 of the cage 40 is then offset in opposite directions in the axial direction by an equal distance f with respect to the joint center O (cage offset).

  As shown in FIG. 3, when the rotation axis X of the outer ring 10 and the rotation axis Y of the inner ring 20 take a certain operating angle θ other than 0 °, a bisector of the angle θ formed by both the rotation axes X and Y If all the balls 30 are in the vertical plane, that is, the joint center plane P, the distances from the ball center to the two rotation axes X and Y are equal to each other. Transmission takes place. The intersection of the joint center plane P and the rotation axes X and Y is referred to as a joint center O. In the fixed type constant velocity universal joint, the joint center O is fixed regardless of the operating angle θ.

  The ball track constituted by the track groove 14 of the outer ring 10 and the track groove 24 of the inner ring 20 that form a pair is provided with a track offset so that the radial direction from the back side of the mouth portion 16 of the outer ring 10 toward the opening end side is provided. It has a wedge shape in which the interval gradually increases.

  Since the cage 40 is provided with the cage offset as described above, the cage 40 has a shape that is thick toward the opening end side of the outer ring 10 and thin toward the opposite opening end side. That is, the thick part 41 is arranged on the opening end side of the outer ring 10, and the thin part 43 is arranged on the opposite opening end side. The outer spherical surface side of the thick portion 41 is extended in the axial direction, and the inner spherical surface side of the thick portion 41 is tapered toward the outer spherical surface.

  Thus, by extending the outer spherical surface side of the thick portion 41 of the cage 40 in the axial direction, the outer spherical surface 42 of the cage 40 and the outer ring 10 can be obtained even in a high angle region when the joint takes the maximum operating angle. A contact area with the inner spherical surface 12 can be ensured. As a result, even when the ball 30 pushes the cage 40 toward the opening end side and the outer spherical surface 42 of the thick portion 41 of the cage 40 and the inner spherical surface 12 of the outer ring 10 rub against each other strongly, the durability is reduced due to heat generation and the transmission torque is reduced. Loss can be minimized. Moreover, since the rigidity of the cage 40 can be ensured to the maximum, the strength of the cage itself is also improved.

  Further, the shaft 50 attached to the inner ring 20 with the joint having the maximum operating angle is formed by a taper shape in which the inner spherical surface side of the thick portion 41 of the cage 40 is enlarged toward the outer spherical surface side. It is possible to prevent interference with the thick portion 41 of the cage 40 (see FIG. 3).

  In the constant velocity universal joint of this embodiment, as shown in FIG. 3 and FIG. 4, the track groove 14 so that the contact point B of the ball 30 that is in the most popping out phase at the maximum operating angle deviates from the track groove 14 of the outer ring 10. To shorten. Thus, by shortening the track groove 14 of the outer ring 10 in the axial direction, it becomes easy to avoid the interference with the shaft 50 and realize a high angle of the joint. In the drawing, the movement locus n of the point where the ball 30 moving in the axial direction in the track groove 14 of the outer ring 10 contacts the track groove 14 is indicated by a dotted line. Further, a contact point B of the ball 30 that has come off the track groove 14 of the outer ring 10 is indicated by a cross in the figure.

  As described above, by shortening the track groove 14 of the outer ring 10, the contact point B of the ball 30 at the most popping out phase (phase angle φ = 0 °) at the maximum operating angle is deviated from the track groove 14. An interference member 60 is provided at the bottom of the opening end of the track groove 14 of the outer ring 10 to apply a pushing force (see the white arrow in FIG. 4) to the ball 30 inward in the radial direction.

  The interference member 60 is made of a ring-shaped metal or rubber / resin, and the ring-shaped interference member 60 is formed in an annular portion formed in a circumferential direction portion including the bottom of the opening end of the track groove 14 of the outer ring 10. The structure is inserted into the slit groove 62. The slit groove 62 is formed on the inner peripheral surface of the circumferential portion including the bottom of the opening end of the track groove 14 of the outer ring 10.

  With such a structure, the interference member 60 can be easily attached to the outer ring 10. The interference member 60 needs to be disposed so as to protrude from the bottom surface of the track groove 14 so that a pressing force can be applied to the ball 30 inward in the radial direction. Further, since the load applied to the ball 30 in the most popping out phase is set to be very small, the load applied to the interference member 60 can also be made very small.

  By providing the interference member 60 as described above, by shortening the track groove 14 of the outer ring 10, even if the ball 30 in the phase that protrudes most at the maximum operating angle is detached from the track groove 14, the track of the outer ring 10 is The interference member 60 disposed at the bottom of the opening end of the groove 14 exerts a pushing force toward the radially inner side with respect to the ball 30 in the most protruding phase. The behavior of the ball 30 can be stabilized until it falls within 14, and the occurrence of vibrations and abnormal noise can be suppressed.

  When it is difficult to form the slit groove 62 on the inner peripheral surface of the circumferential portion including the bottom of the opening end of the track groove 14 of the outer ring 10, as shown in FIGS. An annular concave groove 64 is formed on the end surface of the circumferential portion including the bottom of the opening end of the track groove 14, and the interference member 60 is fitted into the concave groove 64, and a cover 66 is covered on the open end of the outer ring 10. A worn structure is also possible.

  The cover 66 includes a cylindrical portion 66a that is inserted into a step portion formed on the outer peripheral surface of the outer ring 10 by press-fitting or the like, and a flange portion 66b that is bent inward from the cylindrical portion. 66b prevents the interference member 60 from falling off. By making the inner peripheral edge of the flange portion 66b tapered, interference with the shaft 50 is avoided.

When the outer ring 10 and the inner ring 20 take the maximum operating angle θ, the cage offset amount f is set so that the ball 30 can be restrained by the pocket 46 of the cage 40 in order to prevent the ball 30 from jumping out from the opening end 18 of the mouth portion 16 of the outer ring 10. Is set larger than the conventional one. That is, the cage offset amount is f, the radius of the center locus of the ball 30, that is, the center of curvature O ₁ of the track groove 14 of the outer ring 10 or the center of curvature O ₂ of the track groove 24 of the inner ring 20 and the ball 30 when the operating angle is 0 °. Assuming that the length of the line connecting the center O ₅ is PCR, f / PCR is set to be greater than 0 and 0.12 or less.

  Thus, if both the track grooves 14 and 24 of the outer ring 10 and the inner ring 20 are tapered, the maximum operating angle can be increased and the contact length with the ball 30 in the track groove 14 of the outer ring 10 can be secured. Therefore, stable torque transmission can be ensured between the outer ring 10 and the inner ring 20. Further, since the track load and the pocket load of the phase (phase angle φ = 0 °) (see FIGS. 3 and 7) in which the ball 30 is most likely to jump out when the operating angle is taken can be reduced. This is advantageous in the operation of the inner ring 20 in a high angle region. Here, the track load means a load received by the track grooves 14 and 24 from the ball 30 in contact.

  Further, the outer spherical surface 42 of the cage 40 is contact-guided to the inner spherical surface 12 of the outer ring 10, and the inner spherical surface 44 of the cage 40 is contact-guided to the outer spherical surface 22 of the inner ring 20, so that the cage 40 and the outer ring 10 or the inner ring 20 are A spherical force acts between the two, but the maximum value of the spherical force can be reduced and heat generation inside the joint can be suppressed. Furthermore, since the forging die can be easily pulled out, the workability by cold forging is good, and the manufacturing cost can be reduced.

  By making both the track grooves 14 and 24 of the outer ring 10 and the inner ring 20 into a tapered shape, the influence and tendency of the internal force including the track load, pocket load and spherical force described above are verified, and a finite element method (FEM) analysis is performed. By carrying out, the range of the taper angle α (see FIGS. 1 and 2) of the track grooves 14 and 24 was narrowed down and optimally set.

First, the tendency of the internal force (track load, pocket load and spherical force) by increasing the taper angle α of the track grooves 14 and 24 is shown in Table 1. In Table 1, the phase at which the ball 30 is most likely to jump out (phase angle φ = 0 °) and the phase of the ball 30 at which the internal force is maximum, that is, the phase at which the ball 30 is deepest (phase angle φ = Around 180 °) (see FIG. 3 and FIG. 7). The fluctuation range of the spherical force means a difference between the maximum value and the minimum value of the spherical force.

  As apparent from Table 1, when the taper angle α is increased, the maximum value of the pocket load is increased, but the wall thickness of the outer ring 10 is increased at the phase where the ball 30 enters the innermost part (phase angle φ = 180 °), Further, since the strength can be ensured by increasing the cage offset amount and increasing the thickness of the cage 40, there is no problem.

  Next, in order to determine the upper limit value of the taper angle α, a finite element method (FEM) analysis was performed. When the taper angle α is increased, the internal force (track load and pocket load) is reduced at the phase (phase angle φ = 0 °) in which the ball 30 is most likely to jump out, which is advantageous in terms of strength. Since it is the opening end 18 and its wall thickness becomes small, the tendency was confirmed by converting the stress value generated in the track groove 14 into joint strength. The result is as shown in FIG. As apparent from the characteristics shown in the figure, since the joint angle is less than the required strength when the taper angle α is 12.9 °, the upper limit of the taper angle α is defined as 12 °.

  In the above-described embodiment, the case where the track offset is provided is illustrated, but the track offset amount F may be set to 0 without providing the track offset. When the track offset is provided, the arc portion 14a of the track groove 14 of the outer ring 10 becomes shallower toward the inner side, so that the ball 30 positioned at the innermost portion of the track groove 14 rides up when the operating angle is taken. May occur.

Accordingly, the center of curvature O ₁ of the track groove 14 of the outer ring 10 is made to coincide with the center of curvature O ₄ of the inner spherical surface 12, and the center of curvature O ₂ of the track groove 24 of the inner ring 20 is made to be the center of curvature O _{3 of the} outer spherical surface 22. By making the track offset amount F equal to 0, the arc portion 14a of the track groove 14 of the outer ring 10 has a uniform depth without becoming shallow toward the back side. It is possible to suppress the riding of the ball 30 located at the innermost part of the track groove 14.

  The results of the internal force analysis performed by varying each factor of the track offset amount F, the cage offset amount f, and the taper angle α will be described below. Here, with respect to the track offset, the track offset amount F = 0, that is, “no track offset” is set in consideration of the characteristics of the ultra-high angle fixed type constant velocity universal joint in which the allowable load torque does not drop even when entering the high angle region. The cage offset should be as small as possible from the viewpoint of internal force. However, to ensure the function of the joint, a certain amount of cage offset must be provided, so that 0 ≦ f / PCR ≦ 0.150 is varied. It was. The taper angle α was varied in the range from 0 ° to 12 °.

  If the cage offset amount is f = 0 (f / PCR = 0), when the taper angle α is 1.1 ° or more, the track load and the pocket load at the phase (0 ° phase) at which the ball 30 is most likely to jump out are zero. become. On the other hand, when the taper angle α = 12 °, when the cage offset amount f = 3.94 (f / PCR = 0.114) or less, the track load of the phase (0 ° phase) at which the ball 30 is most likely to jump out and Pocket load is zero.

  That is, if the relationship between the cage offset amount f and the taper angle α is set within the hatched region in FIG. 9, the track load and pocket load at the phase (0 ° phase) at which the ball 30 is most likely to jump out are zero. Become. Here, FIG. 9 is plotted based on data calculated by internal force analysis, and the horizontal axis represents the taper angle α (deg) and the vertical axis represents f / PCR.

Thus, the internal specifications that are advantageous in a higher angle operating range are as follows, with the load applied to the phase (0 ° phase) where the ball 30 is most likely to jump out minimized.
Track offset: None Cage offset amount f: 0 <f / PCR ≦ 0.12
Taper angle α: 1 ° ≦ α ≦ 12 °

  Further, in this embodiment, the load at the phase (0 ° phase) where the ball 30 is most likely to jump out is reduced, while the peak load is larger than that of the conventional constant velocity universal joint, so that the strength is ensured. Therefore, it is preferable to arrange the thick portion 41 of the cage 40 toward the opening end side of the outer ring 10.

  For the fixed type constant velocity universal joint according to the present invention (example) and the conventional fixed type constant velocity universal joint (comparative example) according to the present invention, the ball 30 at the maximum operating angle is most likely to jump out. When the track load and the pocket load in the phase (0 ° phase) were calculated, the results were as shown in FIG. From the figure, it can be seen that in the example, both the track load and the pocket load are reduced by 80% or more compared to the comparative example.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the scope of the present invention. The scope of the present invention is not limited to patents. It includes the equivalent meanings recited in the claims, and the equivalent meanings recited in the claims, and all modifications within the scope.

It is sectional drawing which shows embodiment of the fixed type constant velocity universal joint which concerns on this invention. FIG. 2 is a diagram for explaining internal specifications such as a cage offset and a track offset in the constant velocity universal joint of FIG. 1. In the constant velocity universal joint of FIG. 1, it is sectional drawing which shows the state which the inner ring took the maximum operating angle with respect to the outer ring. It is a principal part enlarged view of FIG. In other embodiment of this invention, it is sectional drawing which shows the state which the inner ring | wheel took the maximum operating angle with respect to the outer ring | wheel. It is a principal part enlarged view of FIG. It is sectional drawing which shows the phase of the ball accommodated in the cage. It is a characteristic view which shows the relationship of the joint strength with respect to the taper angle of a track groove. It is a characteristic view which shows the relationship between the taper angle of a track groove, and f / PCR. It is a characteristic view which shows the 0 degree phase load at the time of the basic torque load at the time of a maximum operating angle. It is sectional drawing which shows the prior art example of a fixed type constant velocity universal joint. 12 is a cross-sectional view showing a state in which the inner ring has a maximum operating angle with respect to the outer ring in the constant velocity universal joint of FIG.

Explanation of symbols

10 Outer joint member (outer ring)
12 Inner spherical surface of outer joint member (outer ring) 14 Track groove of outer joint member (outer ring) 18 Open end 20 Inner joint member (inner ring)
22 Outer spherical surface of inner joint member (inner ring) 24 Track groove of inner joint member (inner ring) 30 Ball 40 Cage 42 Outer spherical surface of cage 44 Inner spherical surface of cage 60 Interference member 62 Annular groove (slit groove)
f Cage offset amount F Track offset amount O ₁ Center of curvature of track groove of outer joint member (outer ring) O ₂ Center of curvature of track groove of inner joint member (inner ring) O ₃ Center of inner spherical surface of cage O ₄ Center of outer spherical surface of cage ₄ α Track groove taper angle

Claims (7)

An outer joint member in which a plurality of track grooves are formed on the inner spherical surface at equal intervals in the circumferential direction toward the opening end along the axial direction, and a plurality of track grooves that are paired with the track grooves of the outer joint member are formed on the outer spherical surface. An inner joint member formed along the axial direction at equal intervals in the circumferential direction, a plurality of balls that are interposed between both track grooves of the outer joint member and the inner joint member, and an inner spherical surface of the outer joint member And a cage for holding the ball interposed between the outer spherical surface of the inner joint member,
The outer spherical center and the inner spherical center of the cage are offset to the opposite side by an equal distance in the axial direction with respect to the joint center, and in the longitudinal section of the cage, the opening end side of the outer joint member is made thicker and the opposite opening. Thin the end side,
The outer end of the track groove of the outer joint member is tapered so that the opening end side groove bottom linearly expands toward the opening end, and the anti-opening end side groove bottom of the track groove of the inner joint member is anti-opened. The taper is linearly expanded toward the end,
By shortening the track groove of the outer joint member, an interference member that applies a pushing force toward the inside in the radial direction is applied to the ball that is in the most popping out phase at the maximum operating angle and is released from the track groove. A fixed type constant velocity universal joint, wherein the fixed type constant velocity universal joint is arranged at the bottom of the opening end of the track groove of the member.   The fixed type constant velocity universal joint according to claim 1, wherein an annular groove is formed in a circumferential direction portion including an opening end bottom portion of the track groove of the outer joint member, and a ring-shaped interference member is inserted into the annular groove.   2. A tapered shape in which an opening-side end portion of the outer spherical surface of the cage extends in the axial direction and an opening-side end portion of the inner spherical surface of the cage expands toward the opening-side end portion of the outer spherical surface. Or the fixed type constant velocity universal joint of 2.   The fixed type constant velocity universal joint according to claim 3, wherein the taper angle of the opening side end portion of the inner spherical surface of the cage is equal to or more than half of the maximum operating angle formed by the outer joint member and the inner joint member.   The fixed type constant velocity universal joint according to any one of claims 1 to 4, wherein an upper limit value of a taper angle of both track grooves of the outer joint member and the inner joint member is 12 °.   The cage offset amount f between the outer spherical center and inner spherical center of the cage, and the distance PCR between the center of curvature of the track groove of the outer joint member or the center of curvature of the track groove of the inner joint member and the ball center when the operating angle is 0 °. The fixed constant velocity universal joint according to any one of claims 1 to 5, wherein a ratio value f / PCR with respect to is greater than 0 and equal to or less than 0.12.   The fixed type constant velocity universal joint according to any one of claims 1 to 6, wherein the number of the balls is eight.

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