JP2007170422A - Fixed constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow easy incorporation of a cage in an inner ring by minimizing the cutout of the inner ring and the faucet diameter of the cage. <P>SOLUTION: This fixed constant velocity universal joint comprises: an outer ring 25 having a plurality of track grooves 22 formed in an inner spherical face 21 toward an opening end 23; the inner ring 28 having a plurality of track grooves 27 paired with the track grooves 22 of the outer ring 25 and formed in an outer spherical face 26; a plurality of balls 29 laid between both track grooves 22, 27 of the outer ring 25 and the inner ring 28 for transmitting torque; and the cage 30 laid between the inner spherical face 21 of the outer ring 25 and the outer spherical face 26 of the inner ring 28 for holding the balls 29. Each track groove 22 of the outer ring 25 is in a tapered shape with its diameter linearly enlarged toward the opening end 23, and each track groove 27 of the inner ring 28 is in a tapered shape with its diameter linearly enlarged toward the counter opening end. The outer spherical face center and the inner spherical face center of the cage 30 are offset from the center of the joint by an axially equal distance to the opposite sides. A slit groove 36 is provided in a tapered bottom 27b of each track groove 27 of the inner ring 28. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  In general, as shown in FIG. 13, the fixed type constant velocity universal joint is an outer member in which a plurality of track grooves 2 are formed on the inner spherical surface 1 at equal intervals in the circumferential direction toward the opening end 3 along the axial direction. An outer ring 5, an inner ring 8 as an inner member in which a plurality of track grooves 7 paired with the track grooves 2 of the outer ring 5 are formed on the outer spherical surface 6 along the axial direction at equal intervals in the circumferential direction, and the outer ring 5 Between the track groove 2 of the inner ring 8 and the track groove 7 of the inner ring 8 to transmit torque, and between the inner spherical surface 1 of the outer ring 5 and the outer spherical surface 6 of the inner ring 8, the balls 9 And a cage 10 for holding the The plurality of balls 9 are accommodated in pockets 4 formed in the cage 10 and arranged at equal intervals in the circumferential direction.

  When this constant velocity universal joint is used for a drive shaft of an automobile, the outer ring 5 is connected to a driven shaft, and the drive shaft extending from the sliding type constant velocity universal joint attached to the inner ring 8 on the differential on the vehicle body side is spline-fitted. The structure is connected with. In this constant velocity universal joint, when an operating angle is given between the outer ring 5 and the inner ring 8, the ball 9 accommodated in the cage 10 is always within the bisector of the operating angle at any operating angle. This maintains the constant velocity of the joint.

The above-described fixed type constant velocity universal joint for the need for higher angle has a tapered shape in which the track groove 2 of the outer ring 5 is linearly expanded toward the opening end 3 in order to have a structure capable of obtaining a large operating angle. By making the track groove 7 of the inner ring 8 into a tapered shape linearly expanding toward the opposite opening end, an operation in a high angle region is realized (for example, see Patent Documents 1 to 3).
JP 2001-153149 A JP 2001-304282 A JP 2001-349332 A

  By the way, in the fixed type constant velocity universal joint described above, the inner ring 8 is assembled into the cage 10 in the following manner.

  First, as shown in FIG. 14, the inner ring 8 is moved to the cage 10 in a state where the inner ring 8 is arranged so as to be perpendicular to the axis of the cage 10 (the inner ring 8 is rotated by 90 ° with respect to the cage 10). I try to insert it. The inner ring 8 is inserted into either one of the axial end portions of the cage 10, that is, as shown in FIG. 14, the thin axial end portion 11 disposed on the non-opening end side (back side) of the outer ring 5, Alternatively, as shown in FIG. 16, the measurement is performed from the thick axial end 16 disposed on the opening end side (inlet side).

  When the inner ring 8 is assembled into the cage 10, a notch 13 (see FIG. 15A) is formed at the axial end of the outer spherical surface 12 of the inner ring 8 so that the inner ring 8 can be easily inserted into the cage 10. , Or the spigot portions 15 and 17 (see FIG. 15B) are provided at the axial end of the inner spherical surface 14 of the cage 10.

  When the inner ring 8 is assembled into the cage 10, the inner ring 8 is inserted in a state where the axis is perpendicular to the axis of the cage 10 (the inner ring 8 is rotated by 90 ° with respect to the cage 10). In general, after the outer spherical surface 12 of 8 is dropped into the pocket 4 of the cage 10, the inner ring 8 is rotated by 90 ° so that the axis of the inner ring 8 is aligned with the axis of the cage 10 and placed in a normal posture. is there.

When the inner ring 8 is assembled into the cage 10, in order to further improve the assemblability, the notch 13 (axial dimension X) of the outer spherical surface 12 of the inner ring 8 is increased as shown in FIG. Alternatively, as shown in FIG. 15B, it is easy to increase the inner diameters of the inlay portions 15 and 17 of the cage 10, that is, the inlay diameters Y ₁ and Y ₂ .

However, increasing the pilot diameter Y ₁ of the thin axial end 11 in the axial dimension X or cage 10 of the notch 13 in the inner ring 8, to reduce the thickness at the axial end portion of the inner ring 8 or the cage 10 As a result, there is a problem that the strength and durability of the inner ring 8 or the cage 10 and consequently the strength and durability of the joint are lowered. Therefore, pilot diameter Y ₁ in the axial dimension X or cage 10 of the notch 13 of the inner ring 8 is preferably small as possible desirable.

  Therefore, the present invention has been proposed in view of the above-described problems, and the object of the present invention is to make it easy to incorporate the inner ring cage after making the inner ring notch and cage spigot diameter as small as possible. It is to provide a fixed type constant velocity universal joint.

  In order to achieve the foregoing object, the present invention provides an outer member in which a plurality of track grooves are formed on an inner spherical surface at equal intervals in the circumferential direction toward the opening end along the axial direction, and an outer member is formed on the outer spherical surface. Torque is transmitted via an inner member that is formed along the axial direction with a plurality of track grooves paired with the track grooves at equal intervals in the circumferential direction, and is interposed between the track grooves of the outer member and the track grooves of the inner member. And a cage for holding the ball interposed between the inner spherical surface of the outer member and the outer spherical surface of the inner member, and the track groove of the outer member is linearly directed toward the opening end. The taper is a taper with a diameter increased and the track groove of the inner member linearly expanded toward the opposite opening end, and the outer spherical center and inner spherical center of the cage are axially equal to the joint center. In a fixed constant velocity universal joint that is offset to the opposite side by the distance, the inner member Characterized in that provided along the slit grooves axially tapered bottom of the track grooves.

  In the present invention, by providing a slit groove on the taper bottom of the track groove of the inner member, when the inner member is assembled into the cage, the inner member is arranged so that the axis is perpendicular to the cage axis. When the inner ring is inserted into the cage pocket and the outer spherical surface of the inner member is dropped into the pocket of the cage, the inner part of the cage fits into the slit groove. The outer spherical surface can be dropped deeply into the inlay part of the cage. Further, on the opposite side of the position where the outer spherical surface of the inner member is dropped into the pocket of the cage by 180 °, the margin from the cage spigot portion to the outer spherical edge portion of the inner member increases. As a result, it becomes easy to incorporate the inner member into the cage while reducing the notch of the inner member and the diameter of the cage in the cage as much as possible.

  In the present invention, both the outer member and the inner member are tapered so that the operating angle can be easily increased without increasing the outer diameter of the outer member. In order to prevent the strength and workability of the outer member from being reduced even if the thickness of the member is reduced, the influence and tendency of the track groove being tapered in the internal specifications of this constant velocity universal joint As a result of the verification, 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-described configuration, the cage offset amount f between the outer spherical center and the inner spherical center of the cage and the center of curvature of the track groove of the outer member or the center of curvature of the track groove of the inner member at the operating angle of 0 ° and the ball It is desirable that the value f / PCR of the ratio of the length of the line segment connecting the centers to the 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, by setting the cage offset amount f to be large so that the thick side of the cage is positioned on the open end side of the outer member, the thickness of the cage on the open end side of the outer member is increased. There is an advantage that the strength can be improved. Further, by increasing the thickness of the cage on the opening end side of the outer member, the ball that is about to jump out from the opening end of the outer member can be restrained by the cage when the operating angle is taken.

  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 length PCR of the line segment connecting the center of curvature of the track groove of the outer member or the center of curvature of the track groove of the inner member and the center of the ball is used.

  Therefore, the cage offset amount in the above-described configuration connects the cage offset amount f to the center of curvature of the track groove of the outer member or the center of curvature of the track groove of the inner member and the center of the ball when the operating angle is 0 °. It is desirable that the ratio f / PCR with the line segment length PCR is larger than 0 and not more than 0.12.

  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, a large purpose of the cage offset is to stabilize the position of the ball and hold the ball on the bisector by offsetting the track groove centers of the outer member and the inner member in the axial direction. Without this offset, the position of the ball cannot be determined, so the objective cannot be achieved within a range of 0 or less. 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.

  In the constant velocity universal joint according to the present invention, eight balls can be used in addition to the six balls. By using eight balls, it becomes easy to realize a compact constant velocity universal joint.

  According to the present invention, since the slit groove is provided along the axial direction in the taper bottom of the track groove of the inner member, when the inner member is assembled into the cage, the inlay portion of the cage is fitted into the slit groove. Thus, the outer spherical surface of the inner member can be dropped deeply into the inlay portion of the cage. Further, on the opposite side of the dropping position by 180 °, the margin from the cage spigot to the outer spherical edge of the inner member increases. As a result, it is easy to incorporate the inner member into the cage while reducing the inner member notch and cage spigot diameter as much as possible, and increase the inner member notch and cage spigot diameter. It is possible to prevent the strength of the constant velocity universal joint from being lowered.

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

  The constant velocity universal joint of the embodiment shown in FIG. 1 includes an outer ring 25 as an outer member formed by forming a plurality of track grooves 22 on an inner spherical surface 21 at equal intervals in the circumferential direction toward the opening end 23 along the axial direction. An inner ring 28 as an inner member in which a plurality of track grooves 27 paired with the track grooves 22 of the outer ring 25 are formed on the outer spherical surface 26 along the axial direction at equal intervals in the circumferential direction, and the track grooves 22 of the outer ring 25 A plurality of balls 29 that transmit torque by being interposed between the track grooves 27 of the inner ring 28, and a cage 30 that is interposed between the inner spherical surface 21 of the outer ring 25 and the outer spherical surface 26 of the inner ring 28 and holds the balls 29. It has. The plurality of balls 29 are accommodated in pockets 24 formed in the cage 30 and arranged at equal intervals in the circumferential direction.

  This constant velocity universal joint has a taper shape in which each track groove 22 of the outer ring 25 is linearly expanded toward the opening end 23 of the outer ring 25 in order to have a structure capable of obtaining a large operating angle. That is, the track groove 22 has an arc bottom 22a on the bottom side which is the opposite end side and a tapered bottom 22b on the opening side. On the other hand, each track groove 27 of the inner ring 28 is also tapered so as to linearly expand toward the opposite opening end of the outer ring 25. That is, the track groove 27 has an arc bottom 27a on the opening end side and a tapered bottom 27b on the bottom side.

  Thus, the cage 30 in the fixed type constant velocity universal joint with an increased angle is thick toward the opening end side of the outer ring 25 and thin toward the back side by providing a cage offset as will be described later. It has the shape that became.

  On the other hand, the inner ring 28 is normally incorporated into the cage 30 in a state in which the inner ring 28 is disposed perpendicular to the axis of the cage 30 (the inner ring is rotated by 90 ° with respect to the cage). Is inserted into the cage 30. The inner ring 28 is inserted into the cage 30 at one end in the axial direction, that is, as shown in FIG. 5, the thin-walled axial end 31 disposed on the side opposite to the opening end (back side) of the outer ring 25, Alternatively, as shown in FIG. 6, it is performed from a thick axial end portion 37 arranged on the opening end side (inlet side).

  When the inner ring 28 is assembled into the cage 30, the inner ring 28 is cut into the axial end of the outer spherical surface 26 of the inner ring 28 so that the inner ring 28 can be easily inserted into the cage 30 as shown in FIG. A notch 33 is provided, and as shown in FIG. 2B, spigot portions 35 and 38 are provided at the axial end of the inner spherical surface 34 of the cage 30.

  In the constant velocity universal joint of this embodiment, as shown in FIG. 3, the slit groove 36 is formed in the taper bottom 27b of the track groove 27 of the inner ring 28 along the axial direction by, for example, forging. Here, as shown in FIG. 4, since the track groove 27 of the inner ring 28 has a Gothic arch shape, the ball 29 comes into angular contact with the track groove 27 at two points. Since these two contact points become the contact ellipse m as shown in the figure, the upper limit value of the width t of the slit groove 36 is set so as not to affect the contact ellipse m between the ball 29 and the track groove 27. This is because if the slit groove 36 extends to the contact ellipse m between the ball 29 and the track groove 27, the operability of the joint may be adversely affected.

  Further, as shown in FIG. 2A, the upper limit value of the depth d of the slit groove 36 is set to a level equivalent to that of the undercut free constant velocity universal joint (UJ) in which the inner ring 28 has the same thickness. Is set. The track groove of the inner ring in this undercut free type constant velocity universal joint has a straight bottom parallel to the axis at a portion corresponding to the tapered bottom 27b in the joint of this embodiment. Therefore, the upper limit value of the depth d of the slit groove 36 in the joint of the embodiment is set to a position corresponding to the straight bottom of the track groove of the inner ring in the undercut free type constant velocity universal joint.

In this embodiment, as shown in FIGS. 5 and 6, the slit groove 36 is provided in the tapered bottom 27 b of the track groove 27 of the inner ring 28, so that when the inner ring 28 is assembled into the cage 30, When the inner ring 28 is inserted so that the axis thereof is perpendicular (the inner ring 28 is rotated by 90 ° with respect to the cage 30) and the outer spherical surface 26 of the inner ring 28 is dropped into the pocket 24 of the cage 30, the cage Since the 30 spigot portions 35 and 38 are fitted in the slit groove 36, the outer spherical surface 26 of the inner ring 28 can be dropped deeply into the spigot portions 35 and 38 of the cage 30 (see C ₁ and C ₂ portions in the figure). Further, on the opposite side of the position where the outer spherical surface 26 of the inner ring 28 is dropped into the pocket 24 of the cage 30 (see the D ₁ and D ₂ parts in the figure), the inner ring 28 is moved from the inlay portions 35 and 38 of the cage 30. The margin to the outer spherical edge increases.

As a result, the axial dimension A of the notch 33 in the inner ring 28 [see FIG. 2A] and the inner diameter B ₁ of the thin axial end portion 31 in the cage 30 [see FIG. In addition, the inner ring 28 can be easily assembled into the cage 30 and the strength of the constant velocity universal joint can be prevented from being lowered by increasing the notch 33 of the inner ring 28 and the diameter of the spigot of the cage 30.

  Since the slit groove 36 is formed in parallel with the taper bottom 27b of the track groove 27 of the inner ring 28 along the axial direction, the thickness of the inner ring 28 is reduced and the strength is not lowered. The strength of the can be ensured. Further, in addition to the improvement of the incorporation property, the improvement of grease lubricity and the formation of the slit groove 36 at the time of forging can reduce the processing load at the time of forging, and the life of the mold can be expected to be improved.

  In this embodiment, the slit grooves 36 are provided in all (six) track grooves 27 of the inner ring 28. However, when the inner ring 28 is assembled in the cage 30, the slit groove 36 is formed in any one of the track grooves 27. Should be provided. However, if the slit grooves 36 are provided in all the track grooves 27 as in this embodiment, it is not necessary to consider the directionality (phase) of the inner ring 28 when the inner ring 28 is assembled, so that the incorporation becomes simple. .

  When this constant velocity universal joint is used for a drive shaft of an automobile, the aforementioned outer ring 25 is connected to a driven shaft, and a drive shaft extending from a sliding type constant velocity universal joint attached to the inner ring 28 on a differential on the vehicle body is splined. By adopting a structure connected by fitting, the structure is such that torque can be transmitted while allowing angular displacement between the driven shaft and the drive shaft. In this constant velocity universal joint, when an operating angle is applied between the outer ring 25 and the inner ring 28, the ball 29 accommodated in the pocket 24 of the cage 30 always bisects the operating angle at any operating angle. The joint is maintained at a constant speed.

  FIG. 7 shows an enlarged cross section (hatching is omitted) of FIG. 1 in order to explain the shapes of the track grooves 22 and 27 of the outer ring 25 and the inner ring 28, the track offset and the cage offset.

Since this constant velocity universal joint has a structure capable of taking a large operating angle, the center of curvature O ₃ of the inner spherical surface 34 of the cage 30 and the center of curvature O ₄ of the outer spherical surface 32 are the joint central plane passing through the joint center O. It is offset in the axial direction by an equal distance f with respect to P (cage offset). Note that the center of curvature O ₄ of the outer spherical surface 32 of the cage 30 coincides with the center of curvature of the inner spherical surface 21 of the outer ring 25, and the curvature center O ₃ of the inner spherical surface 34 of the cage 30 is the same as that of the outer spherical surface 26 of the inner ring 28. (In the following description, therefore, the center of curvature of the inner spherical surface 21 of the outer ring 25 is also O _4, and the center of curvature of the outer spherical surface 26 of the inner ring 28 is also O ₃ ). Further, the center of curvature O ₁ of the track groove 22 of the outer ring 25 and the center of curvature O ₂ of the track groove 27 of the inner ring 28 are the center of curvature O ₄ of the inner spherical surface 21 of the outer ring 25 and the center of curvature of the outer spherical surface 26 of the inner ring 28. Each O ₃ is offset in the axial direction by an equal distance F (track offset).

  In this way, the pair of track grooves 22 and 27 forms a wedge-shaped ball track in which the radial interval gradually increases from the back side of the outer ring 25 toward the opening end side. Each ball 29 is incorporated so as to be able to roll between a pair of track grooves 22 and 27, and when the torque is transmitted with the outer ring 25 and the inner ring 28 having an operating angle, the wider one of the intervals between the wedge-shaped ball tracks is larger. Receives axial force to move to.

In order to prevent the ball 29 from jumping out from the open end 23 of the outer ring 25 when the outer ring 25 and the inner ring 28 have the maximum operating angle, the cage offset amount f is set to be larger than that of the conventional one so that the ball can be restrained by the pocket 24 of the cage 30. Also set larger. That is, the cage offset amount is f and the radius of the center locus of the ball 29 at the operating angle of 0 °, that is, the center of curvature O ₁ of the track groove 22 of the outer ring 25 or the center of curvature O ₂ of the track groove 27 of the inner ring 28 and the ball 29. when the length of a line connecting the center _{O 5} and PCR, f / PCR is greater than 0, and is set to be 0.12 or less.

  Thus, if both the track grooves 22 and 27 of the outer ring 25 and the inner ring 28 are tapered, the maximum operating angle can be increased and the contact length with the ball 29 in the track groove 22 of the outer ring 25 can be secured. Therefore, stable torque transmission can be ensured between the outer ring 25 and the inner ring 28. Further, as shown in FIGS. 8 and 9, the track load and the pocket load of the phase (phase angle φ = 0 °) at which the ball 29 is most likely to jump out when the operating angle β is taken can be reduced. This is advantageous in the operation of the inner ring 28 and the inner ring 28 in a high angle region. Here, the track load and the pocket load mean loads that the track grooves 22 and 27 or the pocket 24 receive from the ball 29 in contact therewith.

  Further, the outer spherical surface 32 of the cage 30 is contact-guided to the inner spherical surface 21 of the outer ring 25, and the inner spherical surface 34 of the cage 30 is contact-guided to the outer spherical surface 26 of the inner ring 28, so that the cage 30 and the outer ring 25 or the inner ring 28 are communicated. 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. Further, the outer ring 25 has good workability by cold forging because the forging die can be easily pulled out, and the manufacturing cost can be reduced.

  The present applicant verifies the influence and tendency of the internal force consisting of the track load, the pocket load and the spherical force described above by making both the track grooves 22 and 27 of the outer ring 25 and the inner ring 28 into a tapered shape. By performing (FEM) analysis, the range of the taper angle α (see FIG. 7) of the track grooves 22 and 27 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 22 and 27 is shown in Table 1. In Table 1, the phase at which the ball 29 is most likely to jump out (phase angle φ = 0 °) and the phase of the ball 29 at which the internal force reaches the maximum value, that is, the phase at which the ball 29 enters the deepest (phase angle φ = Around 180 °) (see FIG. 8 and FIG. 9). The fluctuation range of the spherical force means a difference between the maximum value and the minimum value of the spherical force.

  As is apparent from the above table, when the taper angle α is increased, the maximum value of the pocket load is increased, but the wall thickness of the outer ring 25 is increased at the phase where the ball 29 is deepest (phase angle φ = 180 °), Further, since the strength can be ensured by increasing the cage offset amount to increase the cage wall thickness, 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 °) at which the ball 29 is most likely to jump out, which is advantageous in terms of strength. Since it is the opening end 23 and the wall thickness becomes small, the tendency was confirmed by converting the stress value generated in the track groove 22 into the 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 present invention is not limited to this, and the track offset amount F may be set to 0 without providing the track offset. That is, when the track offset is provided, the arc bottom 22a located on the back side of the outer ring 25 becomes shallow toward the back side, so that the ball located at the deepest part of the track groove 22 when the operating angle is taken. 29 rides may occur.

Therefore, the center of curvature O ₁ of the track groove 22 of the outer ring 25 is made to coincide with the center of curvature O ₄ of the inner spherical surface 21, and the center of curvature O ₂ of the track groove 27 of the inner ring 28 is made to be the center of curvature O _{3 of the} outer spherical surface 26. By making the track offset amount F equal to 0, the arc bottom 22a located on the back side of the outer ring 25 has a uniform depth without becoming shallow toward the back side, so the operating angle was taken. Occasionally, the ball 29 located at the innermost part of the track groove 22 can be prevented from climbing.

  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 29 is most likely to jump out are zero. become. On the other hand, if 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 29 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. 11, the track load and the pocket load at the phase (0 ° phase) at which the ball 29 is most likely to jump out are zero. Become. Here, FIG. 11 is drawn 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) at which the ball 29 is most likely to jump out minimized.
Track offset: None Cage offset amount f: 0 <f / PCR ≦ 0.12 (however, the operating angle is 0 °)
Taper angle α: 1 ° ≦ α ≦ 12 °

  Further, in this embodiment, the load at the phase (0 ° phase) where the ball 29 is most likely to jump out is reduced, while the peak load is larger than that of the conventional constant velocity universal joint. In order to ensure, it is preferable to arrange the thick portion of the cage 30 toward the opening end side of the outer ring 25.

  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 whose dimensions are set according to the above-described internal specifications, the phase at which the ball 29 is most likely to protrude (0 ° phase) When the track load and the pocket load in) 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.

It is sectional drawing which shows embodiment of the fixed type constant velocity universal joint which concerns on this invention. (A) is a fragmentary sectional view which shows the inner ring | wheel in the constant velocity universal joint of FIG. 1, (b) is sectional drawing which shows the cage of the constant velocity universal joint of FIG. It is a right view which shows the inner ring | wheel in the constant velocity universal joint of FIG. FIG. 4 is a partially enlarged side view showing a state where a ball is in contact with a track groove of an inner ring in FIG. 3. It is sectional drawing for demonstrating the point which incorporates an inner ring | wheel from the thin axial direction edge part of a cage in embodiment of this invention. In embodiment of this invention, it is sectional drawing for demonstrating the point which incorporates an inner ring | wheel from the thick axial direction edge part of a cage. 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 operating angle with respect to the outer ring. 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 a basic torque load. It is sectional drawing which shows the prior art example of a fixed type constant velocity universal joint. In a prior art example, it is sectional drawing for demonstrating the point which incorporates an inner ring | wheel from the thin axial end part of a cage. In a prior art example, it is sectional drawing for demonstrating the point which incorporates an inner ring | wheel from the thick axial end part of a cage. (A) is a fragmentary sectional view which shows the inner ring | wheel in the constant velocity universal joint of FIG. 13, (b) is sectional drawing which shows the cage of the constant velocity universal joint of FIG.

Explanation of symbols

21 Inner spherical surface of outer member (outer ring) 22 Track groove of outer member (outer ring) 23 Open end 24 Pocket 25 Outer member (outer ring)
26 Outer spherical surface of inner member (inner ring) 27 Track groove of inner member (inner ring) 28 Inner member (inner ring)
29 Ball 30 Cage 32 Cage outer spherical surface 34 Cage inner spherical surface 35, 38 Inner portion 36 Slit groove f Cage offset amount F Track offset amount O ₁ Center of curvature of track groove of outer member (outer ring) O ₂ inner member ( Center of curvature of the track groove of the inner ring O ₃ Center of the inner spherical surface of the O ₃ cage O ₄ Center of the outer spherical surface of the cage α Tapered angle of the track groove

Claims (5)

  An outer member formed with a plurality of track grooves on the inner spherical surface along the axial direction at equal intervals in the circumferential direction, and a plurality of track grooves paired with the track grooves of the outer member on the outer spherical surface. An inner member formed along the axial direction at equal intervals in the circumferential direction, a plurality of balls that transmit torque between the track grooves of the outer member and the track grooves of the inner member, and an outer member And a cage for holding the ball interposed between the inner spherical surface and the outer spherical surface of the inner member, and the track groove of the outer member is tapered so as to linearly expand toward the opening end. The track groove of the inner member is tapered to linearly expand toward the opposite opening end, and the outer spherical center and 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. In the fixed constant velocity universal joint, the trap of the inner member is Fixed type constant velocity universal joint being characterized in that provided along the slit grooves axially tapered bottom of the groove.   The fixed type constant velocity universal joint according to claim 1, wherein an upper limit value of a taper angle of each track groove of the outer member and the inner member is 12 °.   The cage offset amount f between the outer spherical center and the inner spherical center of the cage is connected to the center of curvature of the track groove of the outer member or the center of curvature of the track groove of the inner member and the center of the ball when the operating angle is 0 °. The fixed type constant velocity universal joint according to claim 1 or 2, wherein a value f / PCR of a ratio to the length PCR of the line segment is larger than 0 and equal to or smaller than 0.12.   The fixed type constant velocity universal joint according to any one of claims 1 to 3, wherein a thick side of the cage is positioned on an opening end side of the outer member.   The fixed type constant velocity universal joint according to any one of claims 1 to 4, wherein the number of the balls is eight.

Images