JP2007255491A - Shaft coupling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shaft coupling of such type that transmits power through a cylindrical rolling body arranged at a crossing position of guide grooves crossing mutually and orthogonally between two parallel axes, prevents occurrence of trouble due to inclination of the rolling body, and suppresses increase of its size in the radial direction. <P>SOLUTION: By providing a slider 9 for restraining rotation in a plane including axes of each rolling body 3 in such a way that it overhangs onto only outer peripheral side from a position of a long hole 7 of a retainer 4, each rolling body 3 is kept in parallel with the axial direction of a plate to prevent the rolling bodies 3 from being caught into the guide grooves 5, 6 and reduce distance between adjacent rolling bodies 3 more than that of a shaft coupling provided with a conventional slider so that size of this shaft coupling in the radial direction can be reduced. <P>COPYRIGHT: (C)2008,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).

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

  6 and 7 show an example of the above-described shaft coupling (see Japanese Patent Application No. 2005-154090 (FIGS. 5 and 6)). This shaft coupling is provided with a plurality of guide grooves 53 and 54 on the opposing surfaces of 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, and cylindrical at each guide groove intersection position. The rolling elements 55 are arranged, both end portions thereof are guided by the guide grooves 53 and 54, and the central portion is held through the long hole 57 of the retainer 56. 6 and 7 show the state where both the rotating members 51 and 52 are concentric for the sake of explanation, they are usually used in a state where the rotational axes of both are shifted (eccentric).

  Each of the rolling elements 55 is in rolling contact with the recesses 53a and 54a of the respective guide grooves 53 and 54 via rolling bearings 58 fitted on the outer circumferences of both ends thereof. Further, the central portion of the rolling element 55 is passed through sliders 59 on both sides of the cage 56, and a rolling bearing 60 that rolls in the long hole 57 of the cage 56 is fitted on the outer periphery of a column member that connects both sliders 59. Thus, the rolling element 55 is in a state in which the cage 56 is restrained from moving in the radial direction of the rotating member. In this state, the rolling element 55 is pushed by the driving-side rotating member 51, thereby pushing the driven-side rotating member 52 while driving the inside of the guide grooves 53, 54 and the long hole 57 of the cage 56. To communicate.

  Here, the slider 59 engages with the retainer 56 in a state where the cylindrical rolling element 55 is passed through and restrains rotation in a plane including the axis of the rolling element 55, thereby rotating the rolling element 55. This prevents the trouble of being inclined with respect to the axial direction of the member and biting into the guide grooves 53 and 54.

  However, in the above-described shaft coupling, the slider protrudes from the position of the long hole of the cage to the center side and the outer peripheral side, and the center side and the outer peripheral side of the long hole can be smoothly moved relative to the cage. Since it has a linear motion bearing that is in rolling contact with the edge of the long hole, a certain size is required. For this reason, it is necessary to increase the distance between adjacent rolling elements so that the sliders do not interfere with adjacent ones even if their relative positions are changed with the eccentricity of both rotating members. The number of rolling elements that can be arranged is limited. As a result, the upper limit of the torque load capacity that can be obtained for a certain joint radial size is reduced, and in order to obtain the required torque load capacity, the radial size must be larger than when no slider is provided. There were often no cases.

  On the other hand, if the load capacity is set low and the number of rolling elements is reduced or the amount of eccentricity is reduced, the radial size can be reduced, but the joint performance is reduced and the usable range is limited. .

  An object of the present invention is to prevent a trouble caused by the inclination of a rolling element in a shaft coupling that transmits power via a cylindrical rolling element arranged at a crossing position of guide grooves perpendicular to each other between two parallel axes. In addition, the increase in the radial size is suppressed.

  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 joint configured to transmit power between the rotating members via the rolling elements, and in a plane including the axis of the rolling elements by engaging the rolling elements in a state of passing through the through holes. From the position of the long hole of the cage to the outer peripheral side. It was provided so as to give Ri.

  That is, by providing a slider that restrains rotation in a plane including the axis of each rolling element so that it does not protrude toward the center side of the long hole of the cage, each rolling element is moved in the axial direction of the rotating member by the slider. Keeping them parallel to prevent the rolling elements from getting caught in the guide grooves, and reducing the distance between adjacent rolling elements as compared with the conventional sliders, the size of the joint in the radial direction can be reduced. I was able to plan.

  In the above configuration, the slider and the rolling element are smooth with respect to the cage by interposing a linear motion bearing or a sliding member between each slider and the outer peripheral portion of the long hole of the cage. It is good to be able to move relative to.

  Moreover, if each said slider remove | excludes the cage | basket | center center side corner part of the both ends of the slide direction, the adjacent rolling elements can be brought closer together and the joint will be further miniaturized.

  As described above, the shaft coupling of the present invention is provided so that the slider protrudes only from the position of the long hole of the cage to the outer peripheral side, so that the rolling element is prevented from being caught in the guide groove. In addition to stabilizing the joint operation, the distance between the adjacent rolling elements can be reduced as compared with a shaft joint provided with a conventional slider, and a compact design with a reduced radial size is possible. In addition, since the number of linear motion bearings and sliding members interposed between the slider and the cage is half of the conventional number, the cost of parts is reduced, and the number of processing steps and assembly steps such as grooves for mounting these members are reduced. Can be reduced.

  On the other hand, when the radial size is the same as the conventional size, the number of rolling elements is increased to increase the torque load capacity, or the guide groove of the rotating member and the long hole of the cage are lengthened to increase the eccentric amount. can do. Further, since the linear motion bearing and the sliding member are provided only on the outer peripheral side of the long hole of the cage, the weight of the cage can be reduced by making the hole in the central portion of the cage larger than the conventional one.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 5. 1 to 4 show a first embodiment. As shown in FIGS. 1 and 2, the shaft coupling is a plate (rotating member) 1 that is fixed to each of the input / output shafts A and B that are opposed to each other in the axial direction and are held in parallel with each other. 2, a plurality of cylindrical rolling elements 3 disposed between both plates 1 and 2, and a retainer 4 that restrains movement of each rolling element 3 in the plate radial direction. Power is transmitted between the plates 1 and 2. 1 and 2 show the state where the input / output shafts A and B are concentric for the sake of explanation, but the rotation shafts of the input / output shafts A and B are usually shifted (eccentric) as will be described later. Used in state.

  Each of the plates 1 and 2 is a donut-shaped disk, and is fitted in the outer periphery of the shaft ends of the input shaft A and the output shaft B with a cylindrical portion formed on the inner peripheral side, and fixed in a state of being opposed in the axial direction. Has been. Each of the plates 1 and 2 is provided with a plurality of guide grooves 5 and 6 at equal intervals in the circumferential direction so as to be orthogonal to the guide grooves at corresponding positions on the counterpart plate. In addition, the rolling element 3 is incorporated in parallel with the plate axial direction.

  Each of the guide grooves 5 and 6 is formed so as to extend linearly, and recessed portions 5a and 6a having a certain depth are provided on the inner surface thereof, and both ends of the rolling element 3 are formed by the recessed portions 5a and 6a. Guide the department. In addition, each guide groove does not necessarily need to penetrate a plate like this embodiment, and should just be provided in the opposing surface of both plates.

  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 center of the rolling element 3.

  Each of the rolling elements 3 is in rolling contact with the recesses 5a and 6a of the guide grooves 5 and 6 via rolling bearings 8 fitted on the outer circumferences of both ends thereof. Further, the center of the rolling element 3 is passed through through holes 9 a of a slider 9 provided on both sides of the cage 4, and a long hole of the cage 4 is formed on the outer periphery of the two column members 10 connecting the sliders 9. 7, the rolling bearings 11 that roll in the inside are fitted, and the rolling elements 3 are in a state in which movement in the plate radial direction is restrained by the cage 4.

  Each slider 9 is a rectangular plate-like member, and approximately half of the slider 9 projects from the position of the long hole 7 of the cage 4 to the outer peripheral side, and is a linear motion bearing attached to the surface facing the cage 4. 12 is in rolling contact with the edge of the long hole 7 on the outer peripheral side of the cage 4. As a result, the rotation in the plane including the axis of the rolling element 3 is restricted, and the slider 9 and the rolling element 3 can be smoothly moved relative to the cage 4. In addition, as the linear motion bearing 12, a flat cage in which needle rollers are incorporated is used. Further, a sliding member (slide bearing) may be provided instead of the linear motion bearing.

  Next, the power transmission mechanism of this shaft coupling will be described. When the input shaft A of the shaft coupling is driven to rotate and the plate 1 fixed thereto rotates, the rolling element 3 pushed from the circumferential direction into the guide groove 5 of the input side plate 1 is moved to the plate by the cage 4. Power is transmitted to the output shaft B by pushing the guide groove 6 of the plate 2 fixed to the output shaft B and rotating the output side plate 2 in a state where the movement in the radial direction is constrained. Even if the rotation direction of the input shaft A changes or the driving side and the driven side of the input / output shafts A and B are reversed, power transmission is performed by the same mechanism.

  At this time, each rolling element 3 generates a rotational moment because the acting point and direction of the force received from the plates 1 and 2 are not coaxial, but the engagement between the slider 9 and the cage 4 through which the rolling element 3 passes. Therefore, the rotation in the plane including the shaft is restrained, so that the posture parallel to the plate axis direction can be maintained, and there is no possibility of being caught in the guide grooves 5 and 6.

  The power transmission mechanism is basically the same even in a normal use state where the input / output shafts A and B are eccentric. FIG. 3 shows a state in which the input side plate 1 is decentered upward by the amount of eccentricity e from the concentric state shown in FIGS. 1 and 2, and accordingly, the cage 4 is decentered upward and leftward by e / 2. Show. Even in this state, both the plates 1 and 2 and the cage 4 rotate synchronously without swinging in the same manner as in the concentric state. On the other hand, each rolling element 3 has an inner position of the guide grooves 5 and 6 and the long hole 7 of the cage 4 by changing the crossing position of the guide grooves 5 and 6 and the long hole 7 of the cage 4 in the plate circumferential direction. Power is transmitted between the plates 1 and 2 while moving.

  The state of FIG. 3 is a state in which two adjacent sliders 9 are closest to each other as shown in FIG. At this time, the closest parts of the two sliders 9 shown in FIG. 4 are the corners on the cage center side at one end and the other end in the sliding direction. Therefore, in this state, these sliders 9 do not interfere with each other, but when the sliders are projected toward the center side of the long holes of the cage as in the conventional case, the sliders interfere with each other.

  This shaft coupling has the above-described configuration, and the slider 9 is provided so as to protrude only from the position of the long hole 7 of the cage 4 to the outer peripheral side and not to the center side. The distance between the adjacent rolling elements 3 can be reduced to reduce the radial size.

  FIG. 5 shows a second embodiment. In this embodiment, on the basis of the first embodiment, the adjacent rolling elements 3 are brought closer to each other than in the state of FIG. 3 by removing the cage center side corners at both ends in the sliding direction of each slider 9. The amount of eccentricity can be increased. At the same time, the slider 9 and the linear motion bearing 12 are extended to reduce the contact pressure between the linear motion bearing 12 and the cage 4 so that the slider 9 can move relative to the cage 4 more smoothly. Yes. Although illustration is omitted, it is possible to further reduce the size of the joint by making the amount of eccentricity and the dimensions of the slider 9 and the linear motion bearing 12 the same as in the first embodiment.

Side view of shaft coupling of first embodiment (rotary shafts are concentric) II-II sectional view of FIG. 1 is a side view showing the usage state of the shaft coupling of FIG. 1 (rotary shaft is eccentric) 3 is an enlarged side view of the main part of FIG. The principal part expanded side view corresponding to FIG. 4 of the shaft coupling of 2nd Embodiment. Side view of conventional shaft coupling (rotary shaft is concentric) VII-VII sectional view of FIG.

Explanation of symbols

1, 2 Plate (Rotating member)
DESCRIPTION OF SYMBOLS 3 Rolling body 4 Cage 5, 6 Guide groove 7 Elongate hole 8 Rolling bearing 9 Slider 9a Through hole 10 Column member 11 Rolling bearing 12 Linear motion bearing A Input shaft B Output shaft

Claims (3)

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 slider that engages with a cage in a state in which each of the rolling elements passes through a through hole and restrains rotation in a plane including the axis of the rolling element, It is provided so as to protrude from the position of the long hole to the outer peripheral side Joint.
  2. The shaft coupling according to claim 1, wherein a linear motion bearing or a sliding member is interposed between each slider and a portion on the outer peripheral side of the long hole of the cage.   The shaft coupling according to claim 1 or 2, wherein each slider has a cage center side corner portion removed at both ends in the sliding direction.

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