JP2009228735A - Shaft coupling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve manufacturing efficiency and torque transmission capacity while securing durability, in a shaft coupling of such a type that the other rotating member is sandwiched between two plates forming one rotating member and power is transmitted between both the rotating members through a cylindrical rolling element. <P>SOLUTION: An input plate (the other rotating member) 2 is divided into an input disk (a disk member) 2a and an input shaft (a shaft member) 6. Thereby, in comparison with the case of integral forming, material yield is improved by reducing cutting margins during forming, and no time nor effort are required for correcting a dimension by suppressing deformation during heat treatment and improving dimensional accuracy. At the same time, high-frequency induction hardening is applied to the input shaft 6, thereby improving the torque transmission capacity. The input shaft 6 is axially fixedly connected to the input disk 2a by friction welding, thereby axial backlash is less likely to occur, to provide the durability equivalent to the existing case. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a shaft coupling that couples two parallel shafts to transmit power between the two shafts.

A shaft joint that connects two shafts of a general mechanical device and transmits power from the drive side to the driven side has a different structure depending on the positional relationship between the two shafts to be connected. And those that are parallel to each other (and not concentric). Among these, as a shaft coupling for connecting two parallel shafts, there is a type in which power is transmitted through cylindrical rolling elements arranged at intersections of guide grooves perpendicular to each other between the two parallel shafts. And in this type of shaft coupling, the present applicant sandwiches the other rotating member and the rolling element cage between the two plates constituting one rotating member, and from the center of the other rotating member. The thing of the structure which passed the axial part which protrudes in the center hole of any one plate of one rotation member was proposed (refer patent document 1).
JP 2005-233233 A

  FIG. 9 shows an example of the shaft coupling having the above-described configuration. The shaft coupling includes two output plates 51a and 51b that are coupled to each other so as to be integrally rotatable and constitute an output-side rotating member, an input plate (input-side rotating member) 52 sandwiched between the output plates 51a and 51b, and an input It comprises a plurality of rollers (cylindrical rolling elements) 53 incorporated so as to pass through the plate 52, and two annular retainers 54a, 54b disposed between the output plates 51a, 51b and the input plate 52. The output plate 51a and the input plate 52 on one side have shaft portions 55 and 56 protruding from the center portions thereof, and the shaft portion 56 of the input plate 52 is held by the central hole 51c and the holding of the output plate 51b on the other side. The rotation plates of the output plates 51a and 51b and the input plate 52 are held in parallel with each other through the inner periphery of the container 54b. Note that FIG. 9 shows the output plates 51a and 51b and the input plate 52 concentrically for the sake of explanation. Usually, the output plates 51a and 51b and the input plate 52 are used in a state where the rotation axes of the input side and the output side are shifted (eccentric). The

  In each of the output plates 51a and 51b and the input plate 52, a plurality of guide grooves 57 and 58 are provided so as to be orthogonal to the guide grooves at corresponding positions of the counterpart rotating member. The rollers 53 are passed through the guide grooves 58 of the input plate 52 and the long holes 59 of the retainers 54a and 54b, and the both ends are guided by the guide grooves 57 of the output plates 51a and 51b. It is incorporated at the intersection of the guide grooves 57 and 58. Thereby, the roller 53 pushed by the input plate 52 pushes each output plate 51a, 51b while rolling in a state in which movement in the plate radial direction is restricted by each retainer 54a, 54b so as to transmit power. It has become.

  In other words, the shaft coupling is configured such that the output plates 51a and 51b, the input plate 52, and the cages 54a and 54b are arranged symmetrically with respect to the cross section at the center in the longitudinal direction of the roller 53 that is a cylindrical rolling element. Even if a force is applied to the roller 53 from each of these members during transmission, no rotation moment is generated in the roller 53 to prevent twisting (biting into the guide groove) due to the inclination of the roller 53, and the joint operation is always smooth. To be done.

  However, in the shaft coupling configured as described above, the input plate is a disc-like body portion provided with a plurality of guide grooves on the circumference, and the shaft portion that passes through the center hole of the output plate on the other side. Since these are integrally molded, there are the following problems.

  First, it is desirable that the disk portion of the input plate is subjected to surface hardening treatment on the inner surface of the guide groove where the rolling bearing fitted in the roller makes rolling contact and on both side surfaces which are in sliding contact with the cage, but the shape is complicated and hardness is required. Due to the wide area, when manufacturing the input plate, the entire plate is usually carburized and quenched. However, there is a problem that the bending of the shaft portion with respect to the disk portion is likely to occur due to this carburizing and quenching. The bending of the shaft portion may induce vibration during the rotation of the plate and reduce the durability of the plate. On the other hand, if the bending of the shaft portion is to be corrected by cutting, not only a great effort is required, but also the hardened layer of the shaft portion becomes thin, and the torsional strength is reduced.

  In addition, the shape of the shaft protruding from the center of the disk is difficult to form in a near net shape by cold forging, etc. It is a factor that decreases

  Next, in the output plate through which the shaft portion of the input plate passes, there is a gap larger than the design eccentric amount between the peripheral edge of the center hole and the shaft portion of the concentric input plate, and a predetermined size outside the center hole. Since it is necessary to make the guide groove large enough to be provided, if an attempt is made to suppress an increase in the diameter of the shaft joint in the radial direction, the shaft portion of the input plate becomes thin, which tends to be the weakest part in terms of torsional strength. Moreover, the shaft portion of the input plate is carburized and quenched as described above, but the hardened layer depth is shallower and the torsional strength is lower than when subjected to induction hardening. This lowered the limit of the torque transmission capacity of the entire shaft coupling.

  In order to solve the above-described problem, the input plate may be divided into a disk member and a shaft member. However, if the shaft support part of the input plate or output plate is a free end that is supported by an axially slidable fitting spline joint or the like, the shaft member is connected to the disk member so as to be movable in the axial direction. Then, the position of the shaft member in the axial direction is not determined, and there is a possibility that the shaft member is loosened and the shaft member falls off. In addition, if the shaft member of the input plate is rattled, problems such as abnormal noise and vibration may occur, and problems may occur in the joint characteristics. There is also a risk that the durability may be lowered.

  An object of the present invention is to provide a shaft coupling of a type in which the other rotating member is sandwiched between two plates constituting one rotating member and power is transmitted between the rotating members via a cylindrical rolling element. It is to improve manufacturing efficiency and torque transmission capability while ensuring the performance.

  In order to solve the above-described problems, the present invention integrates two plates in which one of two rotating members, whose rotating shafts are held parallel to each other and not concentric, is disposed at a position sandwiching the other rotating member. A shaft portion protruding from the central portion of the other rotating member is passed through the center hole of one of the plates, and is connected to each plate of the one rotating member and the other rotating member. Are provided so as to be orthogonal to the corresponding guide groove at the corresponding rotating member, the guide groove of the other rotating member is penetrated in the axial direction of the rotating member, and the guide grooves of the two rotating members intersect. A cylindrical rolling element that is passed through the guide groove of the other rotating member and is guided to roll at both ends in the guide groove of each plate of the one rotating member. To restrict the movement of the rotating member in the radial direction In a shaft coupling in which a cage is provided on both sides of the other rotating member so that power is transmitted between the rotating members via the rolling elements, the other rotating member is connected to the one rotating member. The disk member arranged between the two plates and the shaft member forming the shaft portion were divided and the shaft member was connected to the disk member in a state of being fixed in the axial direction.

  In other words, by dividing the other rotating member sandwiched between the two plates of one rotating member into a disk member and a shaft member, the material allowance is improved by reducing the machining allowance at the time of molding compared to the case of integral molding. In addition, the deformation during the heat treatment is suppressed, the dimensional accuracy when the shaft member is connected to the disk member is improved, and the dimensional correction does not take time. At the same time, the shaft member, which tends to be the weakest part in terms of torsional strength, is subjected to appropriate heat treatment to improve the torque transmission capability of the shaft joint. Also, by connecting the shaft member to the disk member in the axially fixed state, even if either of the shaft support portions of both rotating members is a free end, the axial play is unlikely to occur, and durability equivalent to the conventional one Was made available.

  Here, it is desirable that the shaft member of the other rotating member is subjected to induction hardening. In other words, by induction-hardening this shaft member, compared to the case of carburizing and quenching as in the past, the shaft member surely has a deepened quenching depth and improved torsional strength, so that the torque transmission of the entire shaft joint can be improved. Ability can be improved.

  The shaft member of the other rotating member and the disk member can be joined by friction welding. In that case, a concave portion is provided on the side surface of the disk member to accommodate a burr generated around the friction welding surface by friction welding between the shaft member and the disk member so that the burr does not interfere with the cage. It is desirable. Further, if a mechanism for guiding the shaft member toward the center of the disk member so as to coincide with the axial direction is provided in the vicinity of the friction welding portion of the shaft member and the disk member, both members can be joined with higher accuracy. The shaft member can be prevented from being misaligned or tilted with respect to the disk member.

  Alternatively, the shaft member of the other rotating member and the disk member may be spline-coupled to provide an axial retaining mechanism for the shaft member. At this time, as a mechanism for preventing the shaft member from coming off, an engaging portion that engages with the disk member in the axial direction is provided on the axial center side of the spline portion of the shaft member, and is fixed to the tip end portion of the shaft member. It is possible to adopt one fitted with a ring. Also in this case, it is desirable to provide a recess for accommodating the retaining ring on the side surface of the disk member so that the retaining ring does not interfere with the cage.

  Here, the retaining ring of the retaining mechanism for the shaft member is brought into contact with an outwardly tapered surface formed on the inner periphery of the disk member in a state of being elastically reduced in diameter, or is elastically expanded in diameter. If it is made to contact | abut to the inward taper surface formed in the outer periphery of the said shaft member in the made state, the force which presses a disk member to the engaging part of a shaft member will arise, and reduction of the axial play can be aimed at.

  In addition, as a retaining mechanism for the shaft member, an engaging portion that engages with the disk member in the axial direction is provided closer to the center side in the axial direction than the spline portion of the shaft member, and the tip end portion of the shaft member serves as the disk member. If a screw-fastening is used, it can be firmly fixed with less play in the axial direction than when a retaining ring is used.

  As described above, the shaft coupling of the present invention is obtained by dividing the other rotating member sandwiched between the two plates of one rotating member into a disk member and a shaft member. The machining allowance at the time of molding is small, the material yield is high, and the bending due to the heat treatment of the shaft member is small. In addition, the shaft member, which is likely to be the weakest part, can be subjected to heat treatment effective for improving torsional strength such as induction hardening, thereby improving torque transmission capability. In addition, since the shaft member is connected to the disk member in a state of being fixed in the axial direction, the shaft member is less likely to rattle in the axial direction and the same durability as the conventional one can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 8. 1 and 2 show a first embodiment. The basic configuration of this shaft coupling is the same as that of the conventional shaft coupling described above. That is, the shaft coupling is connected to each other so as to be integrally rotatable so as to form two output plates 1a and 1b constituting an output side rotating member, and an input plate (input side rotating member) 2 sandwiched between the two output plates 1a and 1b. , A plurality of rollers (cylindrical rolling elements) 3 incorporated so as to penetrate the input plate 2, and two annular retainers 4a, 4b arranged between the output plates 1a, 1b and the input plate 2 Become. The output plate 1a and the input plate 2 on one side have shaft portions 5 and 6 projecting from the respective central portions, and the shaft portion 6 of the input plate 2 is connected to the central hole 1c and the holding of the output plate 1b on the other side. The rotation plates of the output plates 1a and 1b and the input plate 2 are held in parallel with each other through the inner periphery of the container 4b. FIG. 1 shows that the output plates 1a and 1b and the input plate 2 are concentric for the sake of explanation, but usually the rotational axes of the input side and the output side are shifted as shown in FIG. Used).

  The two output plates 1a and 1b are formed by bolting a cylindrical connecting piece 1d integrally formed on the outer peripheral edge of the output plate 1a on one side and the outer peripheral edge of the output plate 1b on the other side at a plurality of positions in the circumferential direction. By fastening, it is connected so as to be integrally rotatable.

  On the other hand, the input plate 2 is formed by joining an input shaft (shaft member) 6 that is a shaft portion to an input disc (disk member) 2a that is a main body portion disposed between the output plates 1a and 1b by friction welding. Therefore, at the time of manufacture, the unprocessed input shaft 6 is friction-welded to the input disk 2a that has been previously carburized and hardened, and then the outer peripheral surface of the input shaft 6 is induction-hardened. Further, a concave portion 2b for accommodating a burr B generated around the friction welding surface of the input disk 2a and the input shaft 6 is provided on the side surface on the joint side of the input disk 2a.

  The two output plates 1a and 1b and the two retainers 4a and 4b are arranged at symmetrical positions with the input disk 2a of the input plate 2 in between. Here, between the inner peripheral surface of the output plate connecting piece 1d and the outer peripheral surfaces of the input disk 2a and the retainers 4a and 4b of the input plate 2, the outer peripheral surface of the input shaft 6 of the input plate 2 and the output plate on the other side. A predetermined clearance is provided between 1b and the inner peripheral surface of the cage 4b, and these members interfere with each other even when the input side and output side rotating shafts are eccentric as shown in FIG. It is supposed not to.

  Each of the output plates 1a and 1b and the input plate 2 is provided with a plurality of guide grooves 7 and 8 for guiding the roller 3, and each retainer 4a and 4b moves in the plate radial direction through the roller 3. A long hole 9 is provided for restraining.

  The guide grooves 7 of the output plates 1a and 1b are provided so that their circumferential positions coincide between the two plates and extend linearly in a direction that forms a certain angle with the plate radial direction. On the other hand, the guide groove 8 of the input plate 2 penetrates in the plate axial direction and is provided so as to extend linearly perpendicular to the guide groove 7 at the corresponding position of the output plates 1a and 1b. In this example, the guide grooves 7 of the output plates 1a and 1b are also penetrated in the plate axis direction for easy processing. Further, the long holes 9 of the cages 4a and 4b are provided at positions corresponding to the guide grooves 7 and 8 so as to extend linearly in a direction that forms 45 degrees with the guide grooves 7 and 8.

  Each of the rollers 3 passes through the guide groove 8 of the input plate 2 and the long hole 9 of each of the cages 4a and 4b, and is guided in the state where both ends are guided by the guide grooves 7 of the output plates 1a and 1b. The plates 1a, 1b, and 2 are in rolling contact with each other through rolling bearings 10 that are incorporated at the intersections of the grooves 7 and 8 and are fitted to the outer periphery of both ends and the center. The rolling bearing is not limited to the roller bearing as in this example, and a ball bearing may be used.

  When the input plate 2 to which the input torque is applied rotates, the roller 3 pushed from the circumferential direction into the guide groove 8 of the input plate 2 is restrained from moving in the plate radial direction by the cages 4a and 4b. Thus, the power is transmitted to the output side by pushing the guide grooves 7 of the output plates 1a and 1b to rotate the output plates 1a and 1b integrally. Even if the rotation direction of the input torque is changed or the input side and the output side are reversed, power transmission is performed by the same mechanism.

  The power transmission mechanism is basically the same even in a normal use state in which the input and output rotation shafts are eccentric. In this state, as shown in FIG. 2, the crossing positions of the guide grooves 7 and 8 change in the circumferential direction of the plate due to the displacement of the rotation shafts of the output plates 1a and 1b and the input plate 2, and the rollers 3 7 and 8 and the power transmission is performed while moving inside the long holes 9 of the cages 4a and 4b.

  This shaft coupling has the above-described configuration, and the input plate 2 is divided into the input disk 2a and the input shaft 6. Therefore, compared with the case of integrally molding as in the prior art, there is less cutting allowance at the time of molding, and the material yield is reduced. high. In addition, since the bending of the input shaft 6 during heat treatment can be suppressed and the dimensional accuracy when the input shaft 6 is joined to the input disk 2a is high, it does not take time to correct the dimensions and can be manufactured efficiently.

  Furthermore, since the input disk 2a and the input shaft 6 can be subjected to a surface hardening process suitable for each function and shape, the shape is complicated and there are a wide range of parts requiring hardness such as both side surfaces and the guide groove 8 inner surface. The input disk 2a is carburized and hardened to ensure the same surface hardness as the conventional one, while the input shaft 6 having a simple shape, which tends to be the weakest part in terms of torsional strength, is subjected to induction hardening and immersed. Compared to the case of carbon quenching, the quenching depth is increased to improve the torsional strength, thereby improving the torque transmission capacity of the entire shaft joint.

  Moreover, since the input shaft 6 is connected to the input disk 2a in the axial direction by friction welding, any one of the shaft support portions (not shown) of the input shaft 6 and the output plate 1a on one side is free. Even in the case of the end, the axial play is unlikely to occur. Therefore, there is little risk of damage such as dropping of the input shaft 6 due to backlash, generation of abnormal noise or vibration, wear of the connecting portion, etc., and durability equivalent to the conventional one can be obtained.

  Further, a burr B made of a melted material is generated around the friction welding surface of the input disk 2a and the input shaft 6. However, a recess 2b for accommodating the burr B is provided on the side surface of the input disk 2a so that the burr B Since it does not interfere with the inner peripheral surface of the retainer 4b, the retainer 4b does not need to expand its inner diameter more than necessary, and can secure the same strength as the conventional one.

  3 and 4 show a modified example in which a mechanism for guiding the input shaft 6 toward the center of the input disk 2a so that the axial directions coincide with each other in the vicinity of the friction welding portion of the input plate 2 is shown. In the example of FIG. 3, an annular protrusion 11 is provided on the inner wall of the recess 2b of the input disk 2a to guide the tip of the input shaft 6 to form an inlay structure. In the example of FIG. 4, the input disk 2a and the input shaft 6 The friction welding surface is tapered. In these examples, the input disk 2a and the input shaft 6 can be joined with higher accuracy than in the example of FIG. 1, and an axial misalignment of the input shaft 6 and an inclination of the shaft with respect to the input disk 2a can be prevented.

  FIG. 5 shows a second embodiment. In this embodiment, the input shaft 6 of the input plate 2 and the input disk 2a are spline-coupled, and the engaging portion 13 that engages the input disk 2a with a tapered surface closer to the center in the axial direction than the spline portion 12 of the input shaft 6 is. And a retaining ring 14 is fitted into the annular groove 6a at the tip of the input shaft 6 to form a retaining mechanism in the axial direction of the input shaft 6. Further, a recess 2c for accommodating the retaining ring 14 is provided on the side surface of the input disk 2a so that the retaining ring 14 does not interfere with the one side retainer 4a. The configuration of the other parts is the same as that of the first embodiment. In order to suppress backlash between the input disk 2a and the input shaft 6, the spline connection may be press-fitted or a twist angle may be given to the spline.

  6 and 7 show a modification of the input shaft retaining mechanism for the input plate 2 in the second embodiment described above. In the example of FIG. 6, the retaining ring 15 having a circular cross section is brought into contact with an outwardly tapered surface 16 formed on the inner periphery of the input disk 2a in a state of being elastically reduced in diameter. On the other hand, in the example of FIG. 7, the retaining ring 17 having a trapezoidal cross section is elastically expanded in diameter, and its tapered surface is brought into contact with an inwardly tapered surface 18 formed on the outer periphery of the input shaft 6. In these examples, a force for pressing the input disk 2a against the engaging portion 13 of the input shaft 6 is generated, and the play in the axial direction can be reduced.

  FIG. 8 shows a third embodiment. In this embodiment, the retaining ring portion of the input shaft retaining mechanism of the input plate 2 is changed to screwing based on the second embodiment. Specifically, the fixing bolt 19 is screwed into the tip end portion of the input shaft 6 through a flat washer 20 fitted in the recess 2d on one side of the input disk 2a. In the retaining mechanism of this embodiment, the input shaft 6 can be more firmly fixed to the input disk 2a than when a retaining ring is used, and axial backlash can be reduced. As a screwing method, a male screw portion that penetrates the plain washer may be provided at the tip of the input shaft, and a nut may be screwed to the male screw portion of the input shaft outside the flat washer.

Sectional drawing of the shaft coupling of 1st Embodiment The side view which shows the use condition of the shaft coupling of FIG. Sectional drawing of the principal part which shows the modification which added the guide mechanism of the input shaft to the shaft coupling of FIG. Sectional drawing of the principal part which shows another modified example same as the above Sectional drawing of the principal part of the shaft coupling of 2nd Embodiment. Sectional drawing of the principal part which shows the modification of the input shaft retaining mechanism of FIG. Sectional drawing of the principal part which shows another modified example same as the above Sectional drawing of the principal part of the shaft coupling of 3rd Embodiment. Cross section of conventional shaft coupling

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b Output plate 2 Input plate 2a Input disk 2b, 2c, 2d Recess 3 Roller 4a, 4b Cage 5 Shaft part 6 Input shaft 7, 8 Guide groove 9 Long hole 10 Rolling bearing 11 Annular protrusion 12 Spline part 13 Joint part 14, 15, 17 Retaining ring 16, 18 Tapered surface 19 Bolt 20 Plain washer B Burr

Claims (10)

  One of the two rotating members that are held in a state where the rotation axes are parallel to each other and not concentric connect two plates arranged at positions sandwiching the other rotating member so as to be integrally rotatable, and one of the plates The shaft portion protruding from the central portion of the other rotating member is passed through the center hole of the other rotating member, and a plurality of guide grooves are provided in the corresponding rotating member on the other side of each plate and the other rotating member of the one rotating member. The guide groove of the other rotary member is provided at a position where the guide groove of the other rotary member intersects with the guide groove of the other rotary member. A cylindrical rolling element that rolls while being guided at both ends in the guide groove of each plate of the one rotating member, and restricts the movement of each rolling element in the radial direction of the rotating member. Cage on both sides of the other rotating member Thus, in the shaft coupling adapted to transmit power between the two rotating members via the rolling elements, the other rotating member is disposed between the two plates of the one rotating member. A shaft coupling, wherein the shaft member is divided into a member and a shaft member forming the shaft portion, and the shaft member is connected to the disk member in a state of being fixed in the axial direction.   The shaft coupling according to claim 1, wherein the shaft member of the other rotating member is subjected to induction hardening.   The shaft coupling according to claim 1 or 2, wherein the shaft member of the other rotating member and the disk member are joined by friction welding.   The shaft coupling according to claim 3, wherein a concave portion is provided on a side surface of the disk member to accommodate a burr generated around the friction welding surface by friction welding between the shaft member and the disk member.   5. The mechanism according to claim 3, wherein a mechanism is provided in the vicinity of the friction welding portion between the shaft member and the disk member to guide the shaft member toward the center of the disk member so that the axial directions coincide with each other. Shaft coupling.   The shaft coupling according to claim 1 or 2, wherein a shaft member of the other rotating member and a disk member are spline-coupled to provide an axial retaining mechanism for the shaft member.   An engagement portion that engages the disk member in the axial direction is provided in the axial direction center side of the shaft member spline portion with respect to the shaft member retaining mechanism, and a retaining ring is fitted into the distal end portion of the shaft member. The shaft coupling according to claim 6, wherein the shaft coupling is a slant.   The shaft coupling according to claim 7, wherein a recess for receiving the retaining ring is provided on a side surface of the disk member.   The retaining ring is brought into contact with an outwardly tapered surface formed on the inner periphery of the disk member in a state of being elastically reduced in diameter, or is elastically expanded on the outer periphery of the shaft member. The shaft coupling according to claim 7 or 8, wherein the shaft coupling is brought into contact with the formed inwardly tapered surface.   An engagement portion that engages the disk member in the axial direction is provided on the axially central side of the shaft member with respect to the shaft member spline portion, and the tip end portion of the shaft member is screwed to the disk member. The shaft coupling according to claim 6, wherein

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