JP2009174660A - Cage of constant velocity universal joint, propeller shaft assembly and drive shaft assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cage of a constant velocity universal joint, a propeller shaft assembly and a drive shaft assembly, eco-friendly in finishing work of an outer ball surface (an outer diameter surface) of the cage, and enabling cost reduction. <P>SOLUTION: In this constant velocity universal joint, straight line-shaped track grooves 36 and 37 are respectively formed in the axial direction on an outer peripheral surface of an inner race 31 and an inner peripheral surface of an outer race 32 in a state of being mutually inclined in the opposite direction to the axial direction, and a ball 33 is incorporated into a crossing part of both track grooves 36 and 37. In the cage 34, an outer diameter surface 34a has a work surface of applying hardened steel cutting work for performing cutting after heat treatment. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a constant velocity universal joint cage, a propeller shaft assembly, and a drive shaft assembly.

  Constant velocity universal joints, which are power transmission devices used in automobiles and various industrial machines, include a fixed type and a sliding type. Fixed types include Zepper type constant velocity universal joints (BJ) and undercut-free type constant velocity universal joints (UJ). Sliding types include double offset type constant velocity universal joints (DOJ), tripod type, etc. There are a speed universal joint (TJ), a cross groove type constant velocity universal joint (LJ) (Patent Document 1), and the like.

  Cross groove type constant velocity universal joints are used for propeller shafts and drive shafts. Cross-groove type constant velocity universal joints are roughly classified into two types: float type and non-float type, both types depending on the characteristics of the vehicle equipped with a propeller shaft and drive shaft (slide amount, load load, etc.) It is used properly.

  A float type constant velocity universal joint is shown in FIG. 5, and a non-float type constant velocity universal joint is shown in FIG. Both types of constant velocity universal joints include inner rings 1 and 11, outer rings 2 and 12, balls 3 and 13, and cages 4 and 14 as main components.

  The inner rings 1 and 11 are formed with a plurality of track grooves 6 and 16 on the outer peripheral surface thereof. For example, a stub shaft (not shown) of a propeller shaft is inserted into the center holes 5 and 15 of the inner rings 1 and 11 and is spline-fitted so that torque can be transmitted between the two by the spline fitting.

  The outer rings 2 and 12 are positioned on the outer periphery of the inner rings 1 and 11, and track grooves 7 and 17 as many as the track grooves 6 and 16 of the inner rings 1 and 11 are formed on the inner peripheral surface thereof. The track grooves 6 and 16 of the inner rings 1 and 11 and the track grooves 7 and 17 of the outer rings 2 and 12 form an angle inclined in the opposite direction with respect to the axis, and the track grooves 6 and 16 of the inner rings 1 and 11 and the outer ring that make a pair. Balls 3 and 13 are incorporated at intersections with the two and twelve track grooves 7 and 17. The cages 4 and 14 are arranged between the inner rings 1 and 11 and the outer rings 2 and 12, and the balls 3 and 13 are held in the pockets 9 and 19 of the cages 4 and 14. The outer rings 2 and 12 are provided with through holes 10 and 20 for fastening bolts.

As shown in FIG. 5, in the float type, the minimum inner diameter of the cage 4 is set smaller than the maximum outer diameter of the inner ring 1, and in the non-float type, the minimum inner diameter of the cage 14 is set to the maximum outer diameter of the inner ring 11 as shown in FIG. It is set larger than the diameter.
E. R. Wagner “Universal Joint and Driveshaft Design Manual”, SAE, 1991, pp. 163-166. No. 7-47619

  By the way, there is a double offset type (DOJ) as a sliding type, but this double offset type constant velocity universal joint is provided with a linear track groove in the outer ring and the inner ring respectively in parallel with the axial direction, and the outer diameter spherical surface of the cage. The center and the inner spherical surface center are offset in the opposite direction by an equal distance in the axial direction with respect to the pocket center. For this reason, when the operating angle is taken, the ball is positioned on its bisected surface to ensure constant velocity. When the operating angle is applied, the inner ring is the cage inner sphere and the cage is Contact guidance is provided on the inner surface of the outer ring. For this reason, in the DOJ cage, the outer diameter spherical surface and the inner diameter spherical surface are generally subjected to finishing after heat treatment.

  On the other hand, in the cross groove type (LJ), the outer ring track groove and the inner ring track groove intersect each other in the axial direction, thereby restricting the position of the ball (the ball is regulated on the bisector of the operating angle). This is a so-called track steer type constant velocity universal joint that obtains constant velocity. Therefore, the cage is basically established without contact with the outer ring and the inner ring. For this reason, in the cage used for LJ, it is general that the outer diameter spherical surface and the inner diameter spherical surface are not subjected to finishing after heat treatment in order to reduce the processing cost.

  In recent years, in order to improve the vibration characteristics of vehicles, some cross-groove type constant velocity universal joints have been subjected to finish processing (mainly grinding) after heat treatment on the outer diameter surface of the cage. This is because the cage used for the LJ is in a non-contact state with the outer ring and the inner ring, and therefore there is a relatively large clearance between the outer ring and the cage. That is, there is a relatively large radial backlash between the outer ring and the cage. Therefore, as a method of suppressing this, there is an increase in cost, but there is also a method in which the vibration characteristics of the vehicle are improved by grinding the outer spherical surface of the cage to suppress the radial backlash between the outer ring and the cage.

  However, the grinding process that is generally used as a finishing process after heat treatment of metal parts requires the use of a grinding coolant that is unfavorable for the environment that occurs during the grinding process.

  In view of the above problems, the present invention provides a cage, a propeller shaft assembly, and a drive shaft of a constant velocity universal joint that is environmentally friendly and can be manufactured at a low cost for finishing the outer spherical surface (outer diameter surface) of the cage. Provide assembly.

  The cage of the constant velocity universal joint of the present invention is formed in the axial direction in a state where linear track grooves are inclined in opposite directions to the axial direction on each of the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring, In a constant velocity universal joint cage in which balls are incorporated at the intersections of both track grooves, the outer diameter surface has a machined surface subjected to hardened steel cutting that performs cutting after heat treatment. Hardened steel cutting is simply cutting, and since cutting is usually performed in the state of raw material, it was referred to as hardened steel cutting in order to clarify that the cutting was after heat treatment (after quenching).

  According to the cage of the constant velocity universal joint of the present invention, since the formation of the outer surface is a hardened steel cutting, it is not necessary to use grinding coolant in this processing. In addition, contact with the outer ring on the outer diameter surface can be allowed by cutting hardened steel. For this reason, the clearance gap between an outer ring | wheel can be made small and radial backlash can be suppressed.

  Preferably, the processed surface is formed on the entire outer diameter surface, and the surface roughness of the joint function unnecessary portion of the processed surface is larger than the surface roughness of the joint function required portion. For this reason, it is necessary to slow the cutting speed (feeding speed of the cutting blade) in the joint function-required part, but it is possible to increase the cutting speed in the joint function-unnecessary part.

  It is preferable that the surface roughness of the joint function required portion is Ra 0.8 or less. Here, the surface roughness is the arithmetic average roughness, which is a value obtained by folding the roughness curve from the center line and dividing the area obtained by the roughness curve and the center line by the length. Expressed in meters (μm).

  It is also possible to hold 6, 8, or 10 balls.

  When used as a propeller shaft, a boot is attached to the constant velocity universal joint, and the maximum operating angle is regulated by interference between the boot metal ring adapter and the boot band. The angle at this time is 15 ° or less at the maximum, and is usually kept to about 10 ° to 13 °. For this reason, it is preferable that the constant velocity universal joint cage for the propeller shaft has the joint function required portion in a range of 15 ° centering on the axis.

  Similarly, when used as a drive shaft, the maximum operating angle is similarly regulated by the interference between the boot metal ring adapter of the boot and the boot band, and the angle at this time is 25 ° or less at maximum, usually 20 It is held at about 23 °. For this reason, it is preferable that the constant velocity universal joint cage for the drive shaft has the joint function required portion in a range of 25 ° centering on the axis.

  The propeller shaft assembly of the present invention incorporates the cage. The drive shaft assembly of the present invention incorporates the cage.

  According to the cage of the constant velocity universal joint of the present invention, it is not necessary to use grinding coolant in the hardened steel cutting of the outer diameter surface. For this reason, the manufacturing process becomes environmentally friendly, and the processing cost can be reduced. Moreover, in the constant velocity universal joint using this cage, the outer diameter surface of the cage is machined by quenching steel, so that radial play can be suppressed and the vibration characteristics of the vehicle can be improved.

  By making the surface roughness of the joint function unnecessary portion larger than the surface roughness of the joint function required portion, the cutting speed can be increased in the joint function unnecessary portion. Therefore, it is possible to shorten the machining time of the entire outer diameter surface, and it is possible to reduce the work time (machining time) and reduce the cost.

  By setting the surface roughness of the joint function required portion to Ra 0.8 or less, the constant velocity universal joint incorporating the cage of the present invention can exhibit a highly accurate function.

  In addition, it is possible to hold 6, 8, or 10 balls, and it is possible to cope with various types of cross groove type (LJ).

  Even if it is a propeller shaft assembly or a drive shaft assembly, there exists a minimum joint function required part, surface roughness can be made small only in this range, and workability | operativity can be aimed at.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. FIG. 1 shows a constant velocity universal joint (cross-glove type constant velocity universal joint) according to the first embodiment. This constant velocity universal joint includes an inner ring 31, an outer ring 32, a ball 33, and a cage 34 as main components. In this case, it is a float type and is used for a propeller shaft.

  The inner ring 31 has a plurality of track grooves 36 formed on the outer peripheral surface thereof. A stub shaft 40 of a propeller shaft is inserted into the center hole 35 of the inner ring 31 and is spline-fitted so that torque can be transmitted between the two by the spline fitting. That is, the male spline 41 of the stub shaft 40 is formed, and the female spline 42 is formed on the inner diameter surface of the center hole 35 of the inner ring 31. Then, by inserting the stub shaft 40 into the center hole 35 of the inner ring 31, the male spline 41 on the stub shaft 40 side and the female spline 42 on the inner ring 31 side are fitted. Further, a retaining ring 43 for retaining is attached to the end portion of the stub shaft 40.

  The outer ring 32 is located on the outer periphery of the inner ring 31, and the same number of track grooves 37 as the track grooves 36 of the inner ring 31 are formed on the inner peripheral surface thereof. The track groove 36 of the inner ring 31 and the track groove 37 of the outer ring 32 form an angle inclined in opposite directions with respect to the axis, and a ball 33 is formed at the intersection of the track groove 36 of the inner ring 31 and the track groove 37 of the outer ring 32 that make a pair. Is incorporated. A cage 34 is disposed between the inner ring 31 and the outer ring 32, and the ball 33 is held in a pocket 44 of the cage 34.

  The cage 34 is provided with a plurality of (for example, six) pockets 44 at a predetermined pitch along the circumferential direction, and a ball 33 is accommodated in each pocket 44. In this case, the entire outer diameter surface is spherical, and the minimum inner diameter D1 of the cage 34 is set smaller than the maximum outer diameter D2 of the inner ring 31. The number of pockets may be 8, other than 6, or 10 pockets. That is, the number of balls is determined according to the number of pockets. For this reason, the number of balls is 6, 8, 10, or the like.

  A cap (end cap) 45 is attached to the outer ring 32 on the side opposite to the shaft, and the opening on the side opposite the shaft is closed. The cap 45 has a short cylindrical fitting portion 45a to which the outer diameter surface of the outer ring 32 is fitted, an inner flange portion 45b extending from the fitting portion 45a in the inner diameter direction, and an inner diameter portion of the inner flange portion 45b. It comprises a bulging portion 45c that is continuously provided and bulges to the opposite joint side.

  A sealing device 50 is mounted on the shaft protruding side of the outer ring 32. The sealing device 50 includes a boot 51 and a metal boot adapter 52. The boot 51 includes a small-diameter end portion 51a, a large-diameter end portion 51b, and an intermediate folded portion 51c that connects the small-diameter end portion 51a and the large-diameter end portion 51b. The boot adapter 52 has a cylindrical main body portion 52a and an outer ring fitting portion 52b, and the end portion 53 on the opposite outer ring side of the main body portion 52a is crimped to be connected to the large diameter portion 51b of the boot 51. . The outer ring fitting portion 52b includes a short cylindrical fitting portion 54 with which the outer diameter surface of the outer ring 32 is fitted, and an inner flange portion 55 extending from the fitting portion 54 in the inner diameter direction.

  In a state where the outer ring fitting portion 52b of the boot adapter 52 is externally fitted to the outer ring 32, the small diameter end portion 51a of the boot 51 is externally fitted to the stub shaft 40, and the small diameter end portion 51a is tightened by the boot band 58, A boot 51 can be attached to the shaft 40. Note that through holes are provided in the inner flange portion 55 of the boot adapter 52 and the inner flange portion 45b of the cap 45, respectively. A bolt member (not shown) is inserted into the through hole 64 of the boot adapter 52, the through hole 56 provided in the outer ring 32, and the through hole 65 of the cap 45, thereby fastening the boot adapter 52 to the outer ring 32. And the cap 45 are integrated.

  By the way, the surface of the cage 34 is subjected to a curing process. And in the outer diameter surface 34a, hardened steel is cut and a processed surface is formed. Hardened steel cutting is simply cutting, and since cutting is usually performed in the state of raw material, it was referred to as hardened steel cutting in order to clarify that the cutting was after heat treatment (after quenching). Since cutting is performed after quenching, the heat treatment deformation of the material can be removed in this cutting process. When quenching, tensile residual stress tends to remain, and fatigue strength decreases as it is. For this reason, if the surface is cut, a compressive residual stress can be given to the outermost surface portion, thereby improving the fatigue strength. Note that a cutting tool capable of such cutting is used as a cutting tool. As a cutting tool capable of cutting hardened steel, for example, a sintered tool obtained by adding a special ceramic binder to CBN (cubic boron nitride) can be used.

  As the curing process, induction hardening, carburizing and quenching are performed. Quenching by high-frequency heating is a quenching method that applies the principle of heating a conductive object by placing Joule heat in a coil through which high-frequency current flows, and generating Joule heat by electromagnetic induction. is there. Carburizing and quenching is a process in which carbon is impregnated from the surface layer (carburizing treatment) by heating the steel for a long time in a carburizing agent such as gas, liquid or solid containing a lot of carbonized carbon. It is a method of quenching and tempering steel.

  By the way, in such a constant velocity universal joint, the maximum operating angle is regulated by the interference between the adapter 52 and the boot band 58 in the sealing device 50. The angle at this time is 15 ° or less at the maximum, and is usually kept to about 10 ° to 13 °. That is, as shown in FIG. 2, the cage 34 has a joint function required portion 48 in a range (necessary surface roughness range) H1 and a joint function unnecessary portion 49 in a range H2, and the range of the joint function required portion 48 is included. If H1 is a cage 34 of such a constant velocity universal joint for propeller shafts, it will be in the range of β (15 °) centered on the axis.

  Therefore, in the present invention, the cutting speed by the cutting tool is made different between the joint function required portion 48 and the joint function unnecessary portion 49. In this case, the cutting speed of the joint function unnecessary portion 49 is made faster than that of the joint function required portion 48. As a result, the surface roughness of the joint function unnecessary portion 49 is made larger than the surface roughness of the joint function required portion 48.

  The surface roughness of the joint function required portion 48 is set to Ra 0.8 or less. Here, the surface roughness is the arithmetic average roughness, which is a value obtained by folding the roughness curve from the center line and dividing the area obtained by the roughness curve and the center line by the length. Expressed in meters (μm). Thus, if the surface roughness is Ra 0.8 or less, the surface roughness is as small as that of the grinding process.

  According to the cage of the constant velocity universal joint of the present invention, the outer diameter surface 34a becomes a machined surface cut by hardened steel, and the machined surface is machined by hardened steel. There is no need to use. For this reason, the manufacturing process becomes environmentally friendly, and the processing cost can be reduced. Moreover, in the constant velocity universal joint using the cage 34, the outer diameter surface 34a of the cage 34 is cut by quenching steel, so that the outer diameter surface 34a is allowed to contact the outer ring 32 of the joint function required portion 48. can do. For this reason, the clearance gap between the outer ring | wheels 32 can be made small, radial backlash can be suppressed, and the improvement of the vibration characteristic of a vehicle can be aimed at.

  By making the surface roughness of the joint function unnecessary portion larger than the surface roughness of the joint function required portion, the cutting speed can be increased in the joint function unnecessary portion. Therefore, it is possible to shorten the machining time of the entire outer diameter surface, and it is possible to reduce the work time (machining time) and reduce the cost.

  By setting the surface roughness of the joint function required portion to Ra 0.8 or less, the constant velocity universal joint incorporating the cage of the present invention can exhibit a highly accurate function.

  Next, FIG. 3 shows a second embodiment, which is also used for the drive shaft, and the shaft 60 of the drive shaft is inserted into the center hole 35 of the inner ring 31 to be fitted by a spline. Torque can be transmitted between the two by the spline fitting. That is, by forming the male spline 61 of the shaft 60 and inserting the shaft 60 into the center hole 35 of the inner ring 31, the male spline 61 on the shaft 60 side and the female spline 42 on the inner ring 31 side are fitted. . Further, a retaining ring 63 for retaining is attached to an end portion of the shaft 60.

  Also in this case, a cap (end cap) 45 is mounted on the outer ring 32 on the side opposite to the shaft protruding side, and a sealing device 50 is mounted on the outer ring 32 on the shaft protruding side. The sealing device 50 includes a boot 71 and a metal boot adapter 72. The boot 71 includes a small diameter part 71a, a large diameter part 71b, and a bellows part 71c that connects the small diameter part 71a and the large diameter part 71b. The boot adapter 72 has a cylindrical main body portion 72a and an outer ring fitting portion 72b. The end portion 76 on the side opposite to the bellows portion of the large diameter portion 71b of the boot 71 is fitted to the fitting portion 73 of the main body portion 72a, and the boot 71 and the boot adapter 72 are connected. The outer ring fitting portion 72 b includes a short cylindrical fitting portion 74 that fits the outer diameter surface of the outer ring 32, and an inner flange portion 75 that extends from the fitting portion 74 in the inner diameter direction.

  With the outer ring fitting portion 72 b of the boot adapter 72 fitted on the outer ring 32, the small diameter portion 71 a of the boot 71 is fitted on the shaft 60, and the small diameter portion 71 a is tightened by the boot band 78, thereby It can be attached to the shaft 60. Note that through holes 80 and 65 are provided in the inner collar portion 75 of the boot adapter 72 and the inner collar portion 45b of the cap 45, respectively. By tightening a bolt member (not shown) through the through hole 80 of the boot adapter 72, the through hole 56 provided in the outer ring 32, and the through hole 65 of the cap 45, the boot adapter 72 is fixed to the outer ring 32. And the cap 45 are integrated.

  Also in this case, the surface roughness of the joint function unnecessary portion 49 is made larger than the surface roughness of the joint function required portion 48. By the way, the maximum operating angle is regulated by the interference between the adapter 72 of the sealing device 50 and the boot band 78. The angle at this time is 25 ° or less at the maximum, and is usually kept to about 20 ° to 33 °. For this reason, if the range H1 of the joint function required portion 48 is such a cage 34 of a constant velocity universal joint for drive shafts, the range is β (25 °) centered on the axis.

  Even the constant velocity universal joint shown in FIG. 3 has the same effect as the constant velocity universal joint shown in FIG. In this way, even if it is a propeller shaft assembly or a drive shaft assembly, there is a minimum joint function necessary part, and the surface roughness can be reduced only in this range, and workability is improved. Can do.

  In each of the above embodiments, the entire outer diameter surface is spherical, and the cage 34 has a float type in which the minimum inner diameter D1 is set smaller than the maximum outer diameter D2 of the inner ring 31, but as shown in FIG. A non-float type cage 84 may be used. The non-float type cage 84 is formed with a plurality of pockets 94 at a predetermined pitch along the circumferential direction, like the float type cage 34, but the outer diameter surface 84 a is composed of a spherical portion 90 and tapered surfaces 91, 91. Composed.

  For this reason, the minimum inner diameter D11 of the cage 84 is set larger than the maximum outer diameter D2 of the inner ring 31 (see FIG. 1). Also in this case, the outer diameter surface 84 a is hardened steel cut, and the surface roughness of the joint function unnecessary portion 49 is made larger than the surface roughness of the joint function required portion 48.

  Therefore, even when such a cage 84 is used, the same operational effects as when the cage 34 shown in FIG. The cage 84 may be a propeller shaft assembly as shown in FIG. 1 or a drive shaft assembly as shown in FIG.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications can be made. For example, even in the joint unnecessary portion 49, the surface roughness is determined as the joint required portion. It is good also as equivalent surface roughness. Further, the inner diameter surface of the cage 34 may be finished by cutting hardened steel.

It is sectional drawing of the constant velocity universal joint which shows 1st Embodiment of this invention. It is sectional drawing of the cage of the constant velocity universal joint shown in the said FIG. It is sectional drawing of the constant velocity universal joint which shows 2nd Embodiment of this invention. It is sectional drawing which shows other embodiment of a cage. It is sectional drawing of the conventional float type cross groove type constant velocity universal joint. It is sectional drawing of the conventional non-float type cross groove type constant velocity universal joint.

Explanation of symbols

31 Inner ring 32 Outer ring 33 Ball 34 Cage 34a Outer diameter surface 36 Track groove 37 Track groove 48 Joint function required part 49 Joint function unnecessary part

Claims (8)

Linear track grooves are formed in the axial direction on the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring in a state where they are inclined in opposite directions with respect to the axial direction, and balls are incorporated at the intersections of both track grooves. In the constant velocity universal joint cage,
A constant velocity universal joint cage characterized in that the outer diameter surface has a machined surface on which hardened steel is cut after heat treatment.   The said processing surface is formed in the whole outer-diameter surface, The surface roughness of the joint function unnecessary part is made larger than the surface roughness of a joint function required part among processing surfaces, etc. Quick universal joint cage.   3. The constant velocity universal joint cage according to claim 2, wherein the surface roughness of the joint function required portion is Ra 0.8 or less.   The cage of the constant velocity universal joint according to any one of claims 1 to 3, wherein six, eight, or ten balls can be held.   5. The cage of a constant velocity universal joint for a propeller shaft, wherein the joint function required portion is in a range of 15 ° centering on an axis. 6. The described constant velocity universal joint cage.   5. The cage of a constant velocity universal joint for a drive shaft, wherein the joint function required portion is in a range of 25 ° centering on an axis. The described constant velocity universal joint cage.   A propeller shaft assembly in which the cage according to any one of claims 1 to 5 is incorporated.   A drive shaft assembly in which the cage according to any one of claims 1 to 4 or claim 6 is incorporated.

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