JP2006329295A - Shaft coupling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shaft coupling having an always stable operating condition by using a system for transmitting power between two parallel shafts via rolling elements arranged at intersecting positions in guide grooves perpendicular to each other. <P>SOLUTION: Each rolling element 3 is formed in a cylindrical shape with its both ends guided by guide grooves 5, 6 of both plates 1, 2 and its center held passing through an oblong hole 7 of a cage 4. A slider 8 is provided extending in a collar shape from the outer periphery near both ends of each rolling element 3 and engaging with the plates 1, 2 for constraining the rotation of the rolling element 3 in a plane including the axis thereof. Thus, no force works in the axial direction of the plate to cause no axial backlash and the rolling element is held parallel to the axial direction of the plate to prevent the biting of the rolling element 3 into the guide grooves 5, 6, resulting in the always stable operating condition. <P>COPYRIGHT: (C)2007,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).

  Of these, an Oldham coupling is well known as a shaft coupling for connecting two parallel axes. However, when a large amount of power is transmitted to this Oldham joint, there is a case where poor lubrication occurs on the friction surface between the sliders interposed between the two shafts, and the power transmission may not be performed smoothly, and a large amount of eccentricity (2 There is also a problem that the amount of deviation of the shaft in the radial direction cannot be allowed.

  In addition to the Oldham joint, a plate is inserted between two rotating members (disks) facing each other in the axial direction, and linear motion guides are provided at a plurality of positions on the front and back surfaces of the plate, and their operating directions are orthogonal to each other on the front and back surfaces of the plate. A mechanism for transmitting power between both rotating members via a plate and a linear motion guide has been proposed (see Patent Document 1).

  By adopting this mechanism, the required amount of eccentricity can be obtained simply by changing the length of the linear guide, and a large amount of power can be obtained by arranging a plurality of steel balls on the relative movement surface in the linear guide. It can also be transmitted smoothly. However, since a large number of linear motion guides are used, the manufacturing cost is considerably increased, it is difficult to assemble the linear motion guides with high accuracy, and the assembling work becomes very troublesome.

  Therefore, prior to the present invention, the present applicant has proposed a shaft coupling of a type in which power is transmitted via rolling elements arranged at intersecting positions of guide grooves perpendicular to each other between two parallel axes (Japanese Patent Application 2004). -183559).

  FIG. 8 shows an example of the above-described type of shaft coupling. 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 is transferred to each guide groove crossing position. A moving body 55 is arranged, and each rolling element 55 is accommodated in a long hole 57 of a cage 56. 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).

  Each rolling element 55 is pushed by the drive-side rotating member 51 in a state where movement of the rotating member in the radial direction is restrained by the cage 56, whereby the guide grooves 53 and 54 and the long holes 57 of the cage 56 are formed. Power is transmitted by pushing the rotation member 52 on the driven side while rolling inside. Therefore, the frictional resistance at the time of power transmission is small, large power can be transmitted, and a necessary amount of eccentricity can be obtained only by changing the lengths of the guide grooves 53 and 54 and the long hole 57 of the cage 56. Further, since the parts between the rotating members 51 and 52 are only the rolling elements 55 and the retainer 56, the manufacturing cost is low and the assembling property is good.

  By the way, in this shaft coupling, when the rolling element is a sphere, since the sphere contacts the guide groove at a constant contact angle, an axial force that separates both rotating members acts in proportion to the transmission power. Therefore, it is desirable to provide an axial restraint mechanism that restrains changes in the axial spacing between the two rotating members in order to prevent axial rattling during power transmission. However, the provision of the axial restraint mechanism complicates the structure of the shaft joint as a whole and causes frictional resistance at the contact portion with each rotating member, so that the operation is smooth when both rotating members slide relative to each other. May not be performed.

  On the other hand, if the rolling element is a roller (cylindrical body), the roller is incorporated parallel to the axial direction of the rotating member, and its outer diameter surface contacts the inner surface of the guide groove of each rotating member. No axial force is applied, and no axial backlash occurs. Therefore, it is not necessary to provide the above-mentioned axial direction restraining mechanism, the structure of the entire shaft coupling is simplified correspondingly, and the operation at the time of relative sliding of both rotating members becomes smooth. However, since the point and direction of the force that the roller receives from each rotating member and the cage are not coaxial, a rotational moment is generated in the roller, and the roller is guided in a state of being inclined with respect to the axial direction of the rotating member. The problem that it is easy to bite into a groove | channel arises.

In addition, when the rolling element is either a sphere or a roller, the rolling element contacts the guide groove of each rotating member and the long hole of the cage at the same time, so that at least one contact point becomes a sliding contact. It became the resistance at the time of relative sliding.
JP 2003-260902 A

  An object of the present invention is to provide a shaft coupling that can always obtain a stable operating state by transmitting power through rolling elements arranged at intersecting positions of guide grooves orthogonal to each other between two parallel axes. is there.

  In order to solve the above-mentioned problems, the present invention forms each rolling element in a cylindrical shape, guides both ends thereof by the guide grooves, and passes a central portion through a long hole provided in the cage. Rotate in a plane including the axis of the rolling element by holding it and projecting in a bowl shape from the outer circumference of the rolling element to at least one of the one end side and the other end side of each rolling element and engaging with the rotating member at the corresponding position The slider which restrains is provided. In this way, the rolling element is formed in a cylindrical shape, and the slider that engages with the rotating member is provided on the outer periphery of the rolling element, so that the axial force of the rotating member is prevented from acting and the axial play is eliminated. It is possible to eliminate the need for a restraining mechanism and to keep the rolling element parallel to the axial direction of the rotating member and prevent the rolling element from being caught in the guide groove.

  In the above configuration, if a sliding member or a linear motion bearing is interposed between the slider and the rotating member at a corresponding position, the slider and the rolling element can smoothly move relative to the rotating member. .

  In addition, rolling bearings are fitted on the outer circumferences of both end portions and the central portion of each rolling element, and the rolling elements are in rolling contact with the guide grooves of the rotating members and the long holes of the cage via the rolling bearings, respectively. If so, the resistance when the rolling element moves relative to the guide groove and the long hole of the cage can be further reduced.

  As described above, according to the present invention, the rolling element of the shaft coupling is formed in a cylindrical shape, and the slider that engages with the rotating member is provided on the outer periphery thereof, thereby eliminating the axial play and the axial restraint mechanism. In addition to being unnecessary, the rolling element is kept parallel to the axial direction of the rotating member, and the rolling element can be prevented from being caught in the guide groove, so that the shaft coupling can be operated in a stable state at all times.

  In addition, each rolling element is in rolling contact with the guide groove of both rotating members and the long hole of the cage via the rolling bearing, so that the rolling element moves relative to the guide groove and the long hole of the cage. The resistance can be further reduced, and the operation during relative sliding of both rotating members can be made smoother. In addition, heat generated by friction between the rolling elements and each rotating member and cage can be suppressed, and by eliminating the sliding contact portion, damage such as seizure can occur even at high rotations or when large power is transmitted. There is also an effect that it becomes difficult to occur.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 7. 1 to 4 show a first embodiment. As shown in FIGS. 1 and 2 (a) and 2 (b), the shaft coupling is opposed to each of the input / output shafts A and B having the same diameter that are opposed to each other in the axial direction and whose rotating shafts are held parallel to each other. The plates 1 and 2 as rotating members fitted to the shaft end of the shaft, the plurality of cylindrical rolling elements 3 disposed between the plates 1 and 2, and the movement of the rolling elements 3 in the plate radial direction are restrained. It consists of a cage 4 and transmits power between both plates 1 and 2 via each rolling element 3. FIG. 1 shows the state where the input / output shafts A and B are concentric for the sake of explanation, but normally, the input / output shafts A and B are used in a state where the rotation shafts are shifted (eccentric) as described later. Is done.

  Each of the plates 1 and 2 is a donut-shaped disk, and is fitted into the shaft end portions of the input shaft A and the output shaft B with a cylindrical portion formed on the inner periphery, and fixed in a state of being opposed in the axial direction. . Four guide grooves 5, 6 are provided on the opposing surfaces of the plates 1, 2, respectively, at equal intervals in the circumferential direction so as to be orthogonal to the corresponding guide grooves of the counterpart plate. The rolling elements 3 are incorporated in parallel to the plate axis direction at positions where the two guide grooves 5 and 6 intersect.

  The guide grooves 5 and 6 are formed so as to extend linearly in the direction of 45 degrees with the plate radial direction. In the plate thickness direction, guide portions 5a and 6a for guiding both end portions of the rolling element 3 are formed on the surface side, and the inner side is wider than the guide portions 5a and 6a. Storage portions 5b and 6b for storing the slider 8 attached in the vicinity of both ends are formed.

  The cage 4 is formed in an annular shape, and elongated holes 7 extending linearly in a direction perpendicular to the radial direction are provided at four positions at equal intervals in the circumferential direction. 3 through the central part.

  Each of the rolling elements 3 is fitted with ball bearings 9 as rolling bearings on the outer circumferences of both end portions and a central portion thereof, and the guide portions 5a and 6a of the guide grooves 5 and 6 and the holding portions via the ball bearings 9. Each is in rolling contact with the long hole 7 of the vessel 4. And the part accommodated in the accommodating part 5b, 6b of each guide groove 5, 6 protrudes from the outer periphery of the rolling element 3 in the shape of a bowl, and the guide part 5a, 6a of the guide groove 5, 6 and the accommodating part 5b, 6b. A slider 8 that is in sliding contact with the stepped surface is provided so that rotation in a plane including the axis of the rolling element 3 is constrained. A sliding member 10 made of a copper alloy, a synthetic resin or the like and having a low friction coefficient is attached to the sliding contact portion of each slider 8 with the plates 1 and 2. Further, each ball bearing 9 and each slider 8 are fixed with a protruding ring at one end of the rolling element 3 or a retaining ring fitted to the other end, a spacer, a screw or the like so as not to move in the axial direction of the rolling element 3. Has been.

  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 each of the plates 1 and 2 and the cage 4 are not coaxial, but the slider 8 and each plate provided near both ends thereof. Since the rotation in the plane including the shaft is restrained by the engagement with 1 and 2, the posture parallel to the plate axial direction can be maintained.

  The power transmission mechanism is basically the same even in a normal use state in which the rotation axes of the input / output shafts A and B are shifted as shown in FIGS. 3 and 4, the crossing positions of the guide grooves 5 and 6 are changed in the circumferential direction of the plates due to the displacement of the rotation axes of the plates 1 and 2, and the rolling elements 3 are guided by the guide grooves 5 and 6 and Power is transmitted between the plates 1 and 2 while moving in the long hole 7 of the cage 4. In this state, together with the rolling element 3, the slider 8 on one end side thereof is directed to the guide groove 5 of the input side plate 1, and the slider 8 on the other end side is directed to the guide groove 6 of the output side plate 2. Moves linearly relative to each other.

  This shaft coupling has the above-described configuration, and the rolling element 3 is cylindrical, so that no force in the plate axial direction acts during power transmission, and no axial backlash occurs. For this reason, compared with the case where the rolling element is a sphere, the entire structure is simple and the frictional resistance when the plates 1 and 2 are slid relative to each other is less because the axial restraint mechanism is unnecessary. In addition, since the slider 8 that engages with each of the plates 1 and 2 is provided on the outer periphery of the rolling element 3 so that the rolling element 3 does not tilt with respect to the plate axis direction, the rolling element 3 is guided to the guide grooves 5 and 6. Biting does not occur and a stable operating state is always obtained.

  Further, a sliding member 10 is interposed between each slider 8 and the plates 1 and 2 to reduce resistance when the slider 8 moves relative to the plates 1 and 2, and the rolling element 3 is a ball bearing. The rolling element 3 is in rolling contact with the guide grooves 5 and 6 and the long hole 7 of the cage 4 via 9, so that the resistance when the rolling element 3 moves relative to the guide grooves 5 and 6 and the long hole 7 of the cage 4 is reduced. Since it is made small, the operation at the time of relative sliding of both plates 1 and 2 is also performed smoothly.

  In the above-described embodiment, the ball bearing is a rolling bearing that is fitted to the outer periphery of each rolling element, but may be a roller bearing. Further, the sliding member between the slider and the plate is attached to the slider side, but may be attached to the plate side.

  FIG. 5 shows a second embodiment. This shaft coupling is formed based on the first embodiment, with the rear side portions 5c and 6c of the storage portions 5b and 6b of the guide grooves 5 and 6 being substantially the same width as the guide portions 5a and 6a. The sliders 8 are in sliding contact with the step surfaces in the storage portions 5b and 6b, and the sliding members 10 are attached to the sliding contact portions as in the first embodiment.

  In this embodiment, since the contact surface pressure between each slider 8 and the plates 1 and 2 is lower than that in the first embodiment, the progress of wear of these members is suppressed, and the joint life is extended. Moreover, since each slider 8 restrains the axial direction movement of the rolling element 3, the movement of the rolling element 3 becomes more stable.

  6 and 7 (a) and 7 (b) show a third embodiment. This shaft coupling is based on the first embodiment, and the guide grooves 5, 6 are formed with concave guide portions 5a, 6a on the inner surface thereof, and a guide member 11 is formed on the guide portions 5a, 6a. In addition to the slider 8 and the ball bearing 9 of the first embodiment, a slider 12 facing the guide member 11 is attached to both ends of each rolling element 3, and the guide member 11 and the slider 12 are connected to each other. The linear motion bearing 13 is formed by providing V-shaped grooves on the opposed surfaces and arranging a plurality of spheres between the opposed grooves.

  In this embodiment, the slider 12 is engaged with the plates 1 and 2 via the linear motion bearings 13, thereby restricting rotation in a plane including the axis of the rolling element 3. And since the contact of the slider 12 and each plate 1 and 2 is rolling contact, the operation | movement at the time of relative sliding of both plates 1 and 2 is smoother than 1st Embodiment. And since the ball bearing 9 does not need to be fitted in both ends of the rolling element 3, the axial dimension of the entire shaft coupling can be reduced.

  In the examples of FIGS. 6 and 7, the rolling elements of the linear motion bearing are spheres, but cylindrical rollers having different inclination directions may be alternately arranged. Further, the structure of the linear motion bearing is not limited to the structure for a finite track as in the illustrated example, and a structure for an endless track of a type in which rolling elements such as steel balls circulate can also be adopted. In this case, the structure is somewhat complicated, but the bias of the rolling elements is eliminated, so that the reliability of the operation can be expected to be improved.

Side view of shaft coupling of first embodiment (rotary shafts are concentric) a is a sectional view taken along line IIa-IIa in FIG. 1, and b is a sectional view taken along line IIb-IIb in FIG. 1 is a side view showing the usage state of the shaft coupling of FIG. 1 (rotary shaft is eccentric) Sectional view along line IV-IV in FIG. Sectional drawing corresponding to Fig.2 (a) of the shaft coupling of 2nd Embodiment. Partially cutaway side view of shaft coupling of third embodiment (rotary shafts are concentric) a is a sectional view taken along line VIIa-VIIa in FIG. 6, and b is a sectional view taken along line VIIb-VIIb in FIG. Side view of conventional shaft coupling (rotary shaft is concentric)

Explanation of symbols

1, 2 Plate 3 Rolling element 4 Cage 5, 6 Guide groove 7 Long hole 8 Slider 9 Ball bearing 10 Sliding member 11 Guide member 12 Slider 13 Linear motion bearing A Input shaft B Output shaft

Claims (4)

  A plurality of guide grooves are orthogonal to the guide grooves at corresponding positions of the counterpart rotating member 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. A rolling element that rolls while being guided by each guide groove at a position where the guide grooves of the two rotating members intersect with each other, and that holds the rolling members in the radial direction of the rotating member. In the shaft coupling in which power is transmitted between the rotating members via the rolling elements, the rolling elements are formed in a cylindrical shape, and both ends thereof are formed by the guide grooves. Guide and hold the central part through the long hole provided in the cage, and project from the outer periphery of the rolling element to at least one of the one end side and the other end side of each rolling element, and rotate at the corresponding position Engage with the member to constrain rotation in a plane that includes the axis of the rolling element Shaft coupling, characterized in that provided that the slider.   2. The shaft coupling according to claim 1, wherein a sliding member is interposed between each slider and a rotating member at a corresponding position.   The shaft coupling according to claim 1, wherein a linear motion bearing is interposed between each slider and a rotating member at a corresponding position.   Rolling bearings are fitted on the outer circumferences of both end portions and the central portion of each rolling element so that each rolling element is in rolling contact with the guide grooves of both rotating members and the long holes of the cage via these rolling bearings. The shaft coupling according to any one of claims 1 to 3, wherein the shaft coupling is provided.

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