JP2008175287A - Shaft coupling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shaft coupling having a way of transmitting power via a cylindrical rolling element arranged at a crossing position of guide grooves orthogonal to each other between two parallel shafts for surely preventing trouble due to the inclination of the rolling element. <P>SOLUTION: Ball bearings 8 whose outer rings 9 each have an outer peripheral face shaped as a convex face are fitted into the outer peripheries at both ends of a shaft (the cylindrical rolling element) 3 so that the shaft 3 has rolling contact with the inside faces of the guide grooves 5, 6 of both rotating members 1, 2 via the ball bearings 8. Thus, when the shaft 3 is somewhat inclined by backlash or the like between a slider 10 and a cage 4, the bearing outer rings 9 at both ends have stable contact with the inside faces of the guide grooves 5, 6 at the centers of their convex faces to perform smooth rolling without causing pinch, thus suppressing contact surface pressure between the bearing outer ring 9 and each of the guide grooves 5, 6. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a shaft coupling that couples two parallel shafts and transmits 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).

As a shaft coupling for connecting two parallel shafts, the present applicant proposes a method for transmitting power via rolling elements arranged at the intersections of guide grooves orthogonal to each other between the two parallel shafts. (See Patent Document 1).
JP 2005-172217 A

  FIG. 8 shows an example of the above-described shaft coupling (see Japanese Patent Application No. 2005-154090 (FIGS. 5 and 6)). In this axial joint, a plurality of guide grooves 53 and 54 are provided on two rotating members 51 and 52 facing each other in the axial direction so as to be orthogonal to the guide groove on the other side. (Moving body) 55 is arranged, both end portions thereof are guided by the respective guide grooves 53, 54, and the central portion is passed through the elongated hole 57 of the retainer 56 and held. FIG. 8 shows a state in which both the rotating members 51 and 52 are concentric for the sake of explanation, but normally, they are used in a state in which the rotational axes of both are shifted (eccentric).

  The shafts 55 are in rolling contact with the recesses 53a and 54a of the guide grooves 53 and 54 via rolling bearings 58 fitted on the outer circumferences of both ends. In addition, a slider 59 that projects like a bowl is provided at a position sandwiching the large-diameter portion formed at the center thereof, and a pillar member that connects the sliders 59 through the elongated hole 57 of the retainer 56 (not shown). The rolling bearing 60 that rolls in the long hole 57 of the cage 56 is fitted on the outer periphery of the cage 56, so that the shaft 55 is restrained from moving in the radial direction of the rotating member by the cage 56. In this state, the shaft 55 is pushed by the driving-side rotating member 51, thereby pushing the driven-side rotating member 52 while rolling inside the guide grooves 53, 54 and the long hole 57 of the cage 56, thereby generating power. introduce.

  Here, the slider 59 includes the axis of the shaft 55 by engaging with the retainer 56 in a state where the shaft 55 that receives forces having different operating points and directions from the rotating members 51 and 52 and the retainer 56 is passed. The rotation in the plane is constrained so that the shaft 55 does not tilt with respect to the rotating member axial direction.

  However, even with a shaft joint provided with the slider as described above, it is actually difficult to completely eliminate the rotation in the plane including the axis of the rolling element, that is, the inclination of the rolling element. In particular, when a large torque is applied, the rolling element tends to tilt in the torque load direction due to deformation of the connecting member of the slider. Also, a linear motion bearing or the like is provided between the slider and the cage in order to smoothly move both members relative to each other. However, it is inevitable that a slight gap (backlash) is generated. Will tilt. When the rolling element tilts, the rolling bearings fitted to both ends of the rolling element also tilt in the guide groove of each rotating member, and the trouble that the cylindrical outer ring of the bearing bites into the guide groove at its outer peripheral edge (hereinafter referred to as “squeezing” ") Is likely to occur. If the twisting occurs, the outer ring of the bearing stops rotating and the frictional resistance when the rolling element moves in the guide groove increases, so the operating characteristics of the joint deteriorate, and in the worst case the joint locks. Inoperable. Furthermore, the contact surface pressure between the bearing outer ring and the guide groove is remarkably increased, and there is a problem that the joint life is shortened because the contact portions of both members are prematurely worn or damaged.

  Moreover, although such a shaft coupling is intended to transmit power between two parallel axes, in an actual mechanical device, it is difficult to make the two axes connected by the shaft coupling completely parallel. There is often a slight error (misalignment) in the mounting angle. And in the shaft coupling incorporated in this mechanical device with a large misalignment, a rolling element is inclined by an external force, a twist arises, and the above-mentioned problem tends to occur.

  It is an object of the present invention to reliably prevent troubles caused by the inclination of a rolling element in a shaft coupling that transmits power via a cylindrical rolling element that is disposed at the intersection of guide grooves that are orthogonal to each other between two parallel axes. Is to be able to do it.

  In order to solve the above-described problems, the present invention provides a plurality of linearly extending guides on opposing surfaces of two rotating members that are axially opposed and are held in a state where the rotation axes are parallel to each other and not concentric. A cylindrical shape is provided in which a groove is provided so as to be orthogonal to a guide groove at a corresponding position of the counterpart rotating member, and the guide grooves of both the rotating members intersect with each other, and both ends are guided by the guide grooves to roll. A rolling element is provided, and a retainer for restraining movement of each rolling element in the radial direction of the rotating member through a central portion of each rolling element is provided in a linear long hole having a predetermined angle with each guide groove, In a shaft coupling that transmits power between the rotating members via the rolling elements, rolling bearings having outer ring outer peripheral surface shapes that are convex curved surfaces are fitted on the outer periphery of both end portions of the rolling elements. An inner side surface of the guide groove via the rolling bearing It was as rolling contact.

  That is, by making the outer ring outer peripheral surface shape of the rolling bearing fitted into both ends of the rolling element into a convex curved surface, even if the rolling element is slightly inclined, the bearing outer rings at both ends are stably guided at the central part of the convex curved surface. It is in contact with the inner surface of the groove and rolls smoothly without causing twisting, so that the contact surface pressure between the bearing outer ring and the guide groove can be suppressed.

  In the above configuration, a convex curved surface of the outer ring outer periphery of the rolling bearing is a spherical surface, and an inner surface shape of the guide groove is a concave spherical surface having a curvature equal to or smaller than the curvature of the outer ring outer peripheral surface of the rolling bearing; By doing so, the contact surface pressure between the bearing outer ring and the guide groove can be further reduced, and the life of the joint can be extended and the reliability can be improved.

  Further, if the inner side surface shape of the guide groove is a V-groove shape composed of two flat surfaces in contact with the outer ring outer peripheral surface of the rolling bearing, in addition to the reduction of the contact surface pressure between the bearing outer ring and the guide groove, the bearing outer ring The position can be stabilized.

  The convex curved surface of the outer ring outer periphery of the rolling bearing is a spherical surface, and the inner side surface shape of the guide groove has a curvature smaller than the curvature of the outer ring outer peripheral surface of the rolling bearing and contacts the outer ring outer peripheral surface of the rolling bearing. If the shape is composed of two concave spherical surfaces, the position of the bearing outer ring can be stabilized, and the contact surface between the bearing outer ring and the guide groove can be compared to the case where the inner surface shape of the guide groove is a V-groove shape as described above. The pressure can be further reduced.

  Furthermore, when the outer ring of the rolling bearing is incorporated so as to be movable in the axial direction of the rolling element, even when the rolling element is greatly inclined due to the mounting angle error of the two shafts connected by the shaft coupling, The bearing outer ring moves in a direction to mitigate an increase in the contact surface pressure between the bearing outer ring and the guide groove due to the inclination of the rolling element, and it is possible to prevent the twisting from occurring.

  Here, when a needle roller bearing is adopted as the rolling bearing, the rolling element can be moved in the axial direction by forming the outer ring to be narrower than the roller length.

  As described above, the present invention prevents the outer ring of the bearing from being twisted even if the rolling element is slightly inclined with the outer ring outer peripheral surface shape of the rolling bearing that is fitted to both ends of the rolling element of the shaft coupling and is in rolling contact with the guide groove as a convex curved surface. As a result, the operating characteristics of the shaft coupling and the life extension can be improved, and the torque load capacity can be improved.

  In addition, if the outer ring of the rolling bearing is incorporated so as to be movable in the axial direction of the rolling element, it is possible to prevent twisting even when the rolling element is greatly inclined due to the mounting angle error of the two shafts connected by the shaft coupling. Thus, the allowable range of the mounting angle error can be expanded.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 7. 1 and 2 show a first embodiment. This shaft coupling is opposed to each other in the axial direction, and the rotating members 1 and 2 are held in parallel with each other, and a plurality of shafts (cylindrical rolling elements) 3 disposed between the rotating members 1 and 2. And a cage 4 that restrains the movement of each shaft 3 in the radial direction of the rotating member, and transmits power between the rotating members 1 and 2 via each shaft 3. 1 and 2 show the state in which both rotating members 1 and 2 are concentric for the sake of explanation, but the rotational axes of both rotating members 1 and 2 are usually deviated (eccentric) as will be described later. Used in state.

  Each of the rotating members 1 and 2 has a plurality of guide grooves 5 and 6 at equal intervals in the circumferential direction on the disk portions 1b and 2b formed at one ends of the shaft portions 1a and 2a. It is provided so as to be orthogonal to the guide groove at the corresponding position, and the shaft 3 is incorporated at each guide groove intersection position in parallel with the rotating member axial direction.

  Each of the guide grooves 5 and 6 is formed so as to extend linearly, and concave portions 5a and 6a having a certain depth are provided on the inner surface thereof, and both end portions of the shaft 3 are formed by the concave portions 5a and 6a. Is to guide you. In addition, each guide groove does not necessarily need to penetrate the rotating member disk portion as in this embodiment, and may be provided on the opposing surfaces of both rotating members.

  The retainer 4 is formed in an annular shape, and a plurality of elongated holes 7 extending linearly in a direction forming 45 degrees with the guide grooves 5 and 6 are provided at equal intervals in the circumferential direction. And is held through the central portion of the shaft 3.

  Each of the shafts 3 is in rolling contact with the recesses 5a and 6a of the guide grooves 5 and 6 via ball bearings (rolling bearings) 8 that are fitted on the outer periphery of both ends thereof. The outer ring 9 of each of these ball bearings 8 has a convex spherical surface and is in contact with the bottom surfaces of the guide groove concave portions 5a and 6a at the center of the convex spherical surface. Also, a slider 10 that projects like a bowl is provided at a position sandwiching the large diameter portion formed in the central portion of the shaft 3, and two column members that connect the sliders 10 through the long holes 7 of the cage 4. The rolling bearings 12 that roll in the long holes 7 of the cage 4 are fitted into the outer periphery of the cage 11, respectively, so that the shaft 3 is restrained from moving in the radial direction of the rotating member by the cage 4.

  Each slider 10 is brought into rolling contact with the edge of the long hole 7 of the cage 4 by a linear motion bearing 13 attached to a concave portion on the surface facing the cage 4, and rotates in a plane including the axis of the shaft 3. While being restrained, it can move smoothly relative to the cage 4 together with the shaft 3. In addition, the linear motion bearing 13 uses a needle roller incorporated in a flat cage.

  Next, the power transmission mechanism of this shaft coupling will be described. When the input side rotating member 1 of this shaft coupling is driven to rotate, the shaft 3 pushed in the guide groove 5 from the circumferential direction is restrained from moving in the radial direction of the rotating member by the cage 4, and the output side Power is transmitted to the output side by pushing the guide groove 6 of the rotary member 2 and rotating the output side rotary member 2. In addition, even if the rotation direction of the input side rotation member 1 is changed or the driving side and the driven side of both rotation members 1 and 2 are reversed, power transmission is performed by the same mechanism.

  The power transmission mechanism is basically the same even in a normal use state where the rotating members 1 and 2 are eccentric. That is, although illustration is omitted, when the rotating members 1 and 2 are decentered, the intersecting position of the guide grooves 5 and 6 changes in the circumferential direction of the rotating member, and each shaft 3 is the length of the guide grooves 5 and 6 and the cage 4. The power is transmitted while moving inside the hole 7.

  This shaft coupling has the above-described configuration, and even if the shaft 3 is slightly inclined due to play between the slider 10 and the cage 4, the outer ring 9 of the ball bearing 8 fitted to both ends of the shaft 3 is Since it is in contact with the bottom surfaces of the guide groove recesses 5a and 6a stably at the center of the convex spherical surface and rolls smoothly without twisting, the operation characteristics are better and the life is longer than the conventional one.

  The shape of the outer peripheral surface of the outer ring 9 of the ball bearing 8 fitted to both ends of the shaft 3 is not limited to the convex spherical surface as in the above-described embodiment, and is stable with the bottom surfaces of the guide groove concave portions 5a and 6a even if the shaft 3 is slightly inclined. For example, a curved surface whose curvature gradually changes in the bearing width direction can be employed.

  FIG. 3 shows a second embodiment. In this embodiment, needle roller bearings 14 of a type having no inner ring are fitted into both end portions of the shaft 3 of the first embodiment, and the outer peripheral surface shape of the outer ring 15 is a convex spherical surface. When the needle roller bearing 14 is used as a rolling bearing that is fitted to both ends of the shaft 3 in this way, the outer ring 15 cannot essentially be inclined with respect to the shaft 3, so that the outer ring as in the first embodiment. The effect of making the outer ring outer peripheral surface shape a convex spherical surface is greater than when a ball bearing 8 in which 9 is slightly inclined with respect to the inner ring is used.

  FIG. 4 shows a third embodiment. In this embodiment, the inner surface shape of each guide groove 5, 6 of the second embodiment is slightly smaller than the curvature of the outer peripheral surface (convex spherical surface) of the outer ring 15 of the needle roller bearing 14 fitted to both ends of the shaft 3. The concave spherical surface has a small curvature. Thereby, the contact surface pressure between the bearing outer ring 15 and the guide grooves 5 and 6 can be suppressed lower than that in the second embodiment, and it can be expected that the life of the joint is extended and the reliability is improved. Furthermore, since the sliding contact which generate | occur | produced between the side surface of the guide groove recessed parts 5a and 6a of 1st and 2nd embodiment and the bearing outer ring | wheel 15 side is lose | eliminated, when the shaft 3 moves the inside of the guide grooves 5 and 6, Frictional resistance is reduced, and improved operating characteristics can be expected.

  5 and 6 show a fourth embodiment. In this embodiment, as shown in FIG. 5, the outer ring 15 of the needle roller bearing 14 of the third embodiment is formed to be narrower than the roller length so that it can move by a certain amount in the axial direction of the shaft 3. It has changed. Thereby, even if the shaft 3 is largely inclined due to the mounting angle error between the rotating members 1 and 2, the outer rings 15 of the needle roller bearings 14 are located at the positions where the rotating members 1 and 2 approach each other in the circumferential direction. At the position where both the rotating members 1 and 2 move away from each other, the bearing outer rings 15 move toward the end of the shaft 3 (not shown), and the bearing outer rings are caused by the inclination of the shaft 3. The increase in contact surface pressure between 15 and the guide grooves 5 and 6 can be alleviated, and the occurrence of twisting can be prevented.

  FIGS. 7A and 7B show a modification of the guide groove shape of the fourth embodiment in a cross section orthogonal to the guide groove 6 of the output side rotating member 2, respectively. The groove 5 has the same shape as the output side guide groove 6. FIG. 7A shows an example in which the inner surface shape of the guide grooves 5 and 6 of the rotating members 1 and 2 is a V-groove shape composed of two flat surfaces in contact with the outer peripheral surface of the outer ring 15 of the needle roller bearing 14. In addition to the reduction of the contact surface pressure between the bearing outer ring 15 and the guide grooves 5, 6, the position of the bearing outer ring 15 can be stabilized. On the other hand, FIG. 7B shows that the inner surface shape of each guide groove 5, 6 has a curvature smaller than that of the outer peripheral surface (convex spherical surface) of the bearing outer ring 15, and is in contact with the outer peripheral surface of the bearing outer ring 15. In the example having a concave spherical shape (Gothic arch shape), the position of the bearing outer ring 15 can be stabilized as in the example of FIG. 7A, and the bearing outer ring 15 and the guide groove can be more stable than in the example of FIG. The contact surface pressure with 5 and 6 can be reduced. In any of the examples, a clearance 16 that does not require high dimensional accuracy is provided in a portion that does not contact the bearing outer ring 15 in the center of the inner surface of the guide grooves 5 and 6, thereby reducing the processing cost of the guide grooves 5 and 6. It is illustrated.

Side view of the shaft coupling of the first embodiment II-II sectional view of FIG. Sectional drawing corresponding to FIG. 2 of the shaft coupling of 2nd Embodiment Sectional drawing corresponding to FIG. 2 of the shaft coupling of 3rd Embodiment Sectional drawing corresponding to FIG. 2 of the shaft coupling of 4th Embodiment Explanatory drawing of the effect on the mounting angle error of the shaft coupling of FIG. a and b are cross-sectional views showing modifications of the guide groove shape of the shaft coupling of FIG. Sectional view corresponding to FIG. 2 of a conventional shaft coupling

Explanation of symbols

1, 2 Rotating member 3 Shaft (cylindrical rolling element)
4 Cage 5, 6 Guide groove 7 Long hole 8 Ball bearing 9 Outer ring 10 Slider 11 Column member 12 Rolling bearing 13 Linear motion bearing 14 Needle roller bearing 15 Outer ring

Claims (6)

  A plurality of linearly extending guide grooves are formed on the opposing surfaces of the two rotating members that are axially opposed and are held in a state where the rotation axes are parallel to each other and not concentric. Cylindrical rolling elements that roll while being guided by both ends of each guide groove are provided at positions where the guide grooves of the two rotating members intersect with each other. A retainer is provided in a linear long hole that forms an angle of through the central portion of each rolling element to restrain the movement of each rolling element in the radial direction of the rotating member, and between the two rotating members via each rolling element. In a shaft coupling adapted to transmit power, a rolling bearing having an outer ring outer peripheral surface shape of a convex curved surface is fitted on the outer periphery of both end portions of the rolling element, and the rolling element is inserted into the guide groove via these rolling bearings. It is characterized by rolling contact with the inner surface of Joint.   The convex curved surface of the outer ring outer periphery of the rolling bearing is a spherical surface, and the inner surface shape of the guide groove is a concave spherical surface having a curvature equal to or smaller than the curvature of the outer ring outer peripheral surface of the rolling bearing. The shaft coupling according to claim 1.   2. The shaft coupling according to claim 1, wherein an inner side surface shape of the guide groove is a V-groove shape formed of two planes in contact with an outer peripheral surface of the outer ring of the rolling bearing.   The convex curved surface on the outer ring outer periphery of the rolling bearing is a spherical surface, and the inner side surface shape of the guide groove has a curvature smaller than the curvature of the outer ring outer peripheral surface of the rolling bearing and is in contact with the outer ring outer peripheral surface of the rolling bearing. The shaft coupling according to claim 1, wherein the shaft coupling has a concave spherical surface.   The shaft coupling according to any one of claims 1 to 4, wherein an outer ring of the rolling bearing is incorporated so as to be movable in an axial direction of the rolling element.   6. The shaft coupling according to claim 5, wherein a needle roller bearing is employed as the rolling bearing, and the outer ring is formed narrower than the roller length so as to be movable in the axial direction of the rolling element. .

Images