JP2008082361A - Shaft coupling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten an axial size, reduce an internal space, and improve a torque load capacity in a shaft coupling of a type transmitting power via cylindrical rolling elements arranged in a crossing position of mutually orthogonal guide grooves between two parallel shafts. <P>SOLUTION: The shaft coupling is structured such that one slider 8 protruding like a collar from an outer circumference is provided on each shaft (the cylindrical rolling element) 3, two retainer pieces 4a, 4b axially facing each other with the slider 8 in between to form a retainer 4, and rotation is constrained in a plane including an axis of the shaft 3 by engagement of the slider 8 and the retainer 4. Thereby, the axial size can be shortened, and the internal space is reduced in comparison with a conventional one with two sliders provided in each shaft. By improving rigidity of a connection part of both retainer pieces 4a, 4b, the torque load capacity can be improved also. <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

  4 and 5 show an example of the above-described shaft coupling (see Japanese Patent Application No. 2005-154090). 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. 4 and 5 show the state in which 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).

  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. Further, two sliders 59 project from the outer periphery of the shaft 55 so as to sandwich the retainer 56, and roll in the elongated hole 57 of the retainer 56 on the outer periphery of the column member 60 connecting both the sliders 59. The rolling bearing 61 to be fitted is fitted, and the shaft 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 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.

  At this time, forces having different operating points and directions are applied to the shaft 55 from both rotating members 51 and 52 to generate a rotational moment. However, a slider 59 integral with the shaft 55 engages with the cage 56 to engage the shaft 55. By restricting rotation in a plane including the axis of the shaft, the shaft 55 maintains a posture parallel to the axial direction of the rotating member, and a trouble (hereinafter referred to as “twisting”) occurs in which the shaft 55 is engaged with the guide grooves 53 and 54. There is no such thing. Here, the two sliders 59 facing each other across the cage 56 receive vertical drag (hereinafter referred to as “separation force”) in a direction in which the sliders 59 are separated from the cage 56. Is received by a column member 60 connecting both sliders 59.

  By the way, in this shaft coupling, it is necessary to provide the slider 59 with a certain degree of rigidity so that each slider 59 can be engaged with the cage 56 and receive the rotational moment generated in the shaft 55. Further, in order to smoothly move the slider 59 in a linear motion, a linear motion bearing (hereinafter also referred to as “linear motion bearing”) 62 is provided on the surface of the slider 59 facing the cage 56, and the space for that is also provided. It is necessary to design the slider 59 in consideration of this. As a result, the slider 59 becomes thick in the axial direction, and the axial dimension of the entire joint becomes large.

  A space is formed between the sliders 59 adjacent to each other in the circumferential direction of the rotating member so that the rotating members 51 and 52 and the retainer 56 are separated by the thickness of the slider 59. Since the volume of this space is large, when the periphery of the space between the rotating members 51 and 52 is closed with a boot (not shown) and a lubricant such as grease is enclosed therein, the amount of lubricant used increases, Running costs are high. In addition, since the interval between the rotating members 51 and 52 and the cage 56 is wide, the lubricant is likely to be scattered to the outer peripheral side by centrifugal force, and it is difficult to obtain a lubricating effect on the stability of the joint operation.

  Furthermore, as described above, in order to receive the rotational moment generated in the shaft 55 by the slider 59, the rigidity of the slider 59 is required. In addition, the column member 60 that connects the sliders 59 is also required to have high rigidity. It is done. However, in actuality, the column member 60 needs to be formed in a cross-sectional area that can pass through the long hole 57 of the cage 56, so that it is difficult to ensure sufficient rigidity, which limits the torque load capacity of the joint. Often. In addition, the column member 60 may be deformed due to insufficient rigidity, and the inclination of the shaft 55 cannot be suppressed, and a twist may occur.

  An object of the present invention is to reduce axial dimensions and internal space in a shaft coupling that transmits power via cylindrical rolling elements disposed at intersecting positions of guide grooves perpendicular to each other between two parallel axes. And to improve the torque load capacity.

  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 to be guided by the guide grooves at both ends. 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, Power is transmitted between the rotating members via each rolling element, projecting from the outer periphery of the rolling element in a bowl shape, engaged with the retainer, and rotated in a plane including the axis of the rolling element. In a shaft coupling provided with a slider for restraining, the cage is connected to the slide. Two retainer pieces arranged at positions sandwiching the was a concatenation.

  That is, one slider is projected from the outer periphery of each rolling element, two cage pieces are arranged so as to face each other in the axial direction with this slider interposed therebetween, and both cage pieces are connected to form a cage. By adopting the structure, the axial dimension can be shortened and the internal space can be reduced as compared with the conventional structure in which two rolling elements are provided on each rolling element and connected by a column member. In addition, since the force corresponding to the separation force acting on the two conventional sliders is received by the two cage pieces with little radial size restriction, the connecting portion of both cage pieces is rigid. As a high thing, torque load capability can be improved.

  In the above configuration, by interposing a linear motion bearing between the slider and each cage piece, the slider and the shaft can be smoothly moved relative to the cage to stabilize the joint operation at the time of eccentricity. it can.

  If the slider and the rolling element are integrally formed, the number of parts and the number of assembling steps can be reduced, and an improvement in torque load capacity can be expected by improving the strength of the rolling element.

  As a means for connecting the two cage pieces, any one of a screw, a retaining ring, caulking, and welding may be employed.

  In the present invention, as described above, a single slider is provided for each rolling element of the shaft coupling, and two cage pieces facing each other in the axial direction with this slider interposed are connected to form a cage. Compared with the conventional one in which each rolling element is provided with two sliders, the axial dimension can be shortened, and the thickness can be reduced while maintaining the torque load capability. In addition, since the internal space is reduced and the volume of the useless space is reduced, the amount of lubricant used is reduced, the running cost is reduced, and the interval between each rotating member and the cage is reduced. Can hardly be scattered to the outer peripheral side, and the stability of the joint operation can be reliably improved. Furthermore, by increasing the rigidity of the portion that receives the rotational moment generated in the rolling elements, it is possible to improve the torque load capability and to suppress the tilting of the rolling elements and prevent the twisting.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 3. 1 and 2 show a first embodiment. This shaft coupling is opposed to the plates (rotary members) 1 and 2 fixed to the input / output shafts A and B, which are opposed to each other in the axial direction and whose rotation shafts are held in parallel with each other. Are provided with a plurality of shafts (cylindrical rolling elements) 3 and a cage 4 that restrains the movement of each shaft 3 in the plate radial direction, and power is transmitted between the plates 1 and 2 via each shaft 3. To communicate. 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, fitted into the outer periphery of the shaft end portions of the input shaft A and the output shaft B, and fixed in a state of being opposed in the axial direction. 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 corresponding guide grooves of the counterpart plate. The shaft 3 is incorporated in parallel with the plate axis 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 a plate like this embodiment, and should just be provided in the opposing surface of both plates.

  The cage 4 is formed by connecting two cage pieces 4a and 4b formed in a donut shape so as to face each other in the axial direction. Each of the cage pieces 4a and 4b is provided with a plurality of elongated holes 7 extending linearly in the direction of 45 degrees with the respective guide grooves 5 and 6 at the same interval in the circumferential direction. The shaft 3 is passed through, and the slider 8 is connected in a state of sandwiching the slider 8 protruding from the outer periphery of the central portion in a hook shape. Further, the connection is performed by screwing the screw 9 into the output side retainer piece 4b from the outer side surface of the input side retainer piece 4a. However, as other connection means, a retaining ring, caulking, welding or the like can be used. It can also be adopted.

  The shafts 3 are in rolling contact with the recesses 5a and 6a of the guide grooves 5 and 6 via rolling bearings 10 fitted on the outer circumferences of both ends. Further, two shaft members 11 pass through the slider 8 fitted on the outer periphery of the central portion thereof in parallel with the shaft 3, and roll in the long holes 7 of the cage 4 at both ends of each shaft member 11. The rolling bearing 12 to be fitted is fitted, and the shaft 3 is in a state in which movement in the plate radial direction is restrained by the cage 4.

  The slider 8 is in rolling contact with the edges of the long holes 7 of the cage pieces 4a and 4b by linear motion bearings 13 attached to the recesses on both side surfaces thereof. , And the slider 8 and the shaft 3 can smoothly move relative to the cage 4. 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 shaft A of the shaft coupling is driven to rotate and the plate 1 fixed thereto rotates, the shaft 3 pushed from the circumferential direction into the guide groove 5 of the input side plate 1 is moved by the retainer 4 to the plate diameter. 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 of the 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 shaft 3 is not coaxial with the point of action and direction of the force received from each plate 1 and 2, so that a rotational moment is generated. Since the rotation in the plane including the shaft is restricted, 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. That is, although illustration is omitted, when the input / output shafts A and B are decentered, the intersecting position of the guide grooves 5 and 6 changes in the circumferential direction of the plate, and each shaft 3 has a long hole in the guide grooves 5 and 6 and the cage 4. The power is transmitted between the plates 1 and 2 while moving inside 7.

  This shaft coupling is configured as described above, and one shaft 8 is provided for each shaft 3, and two cage pieces 4 a and 4 b facing each other with these sliders 8 are connected to form a cage 4. Therefore, the axial dimension can be shortened as compared with the conventional one (see FIGS. 4 and 5) in which two sliders are provided on each shaft. This shortening of the axial dimension not only reduces the space occupied by the slider but also reduces the rotational moment generated on the shaft, so the rigidity of the part that receives the rotational moment and the load capacity of the linear motion bearing are designed to be small accordingly. As a result, it is possible to further reduce the thickness.

  Moreover, since the space | interval between each plate 1 and 2 and the holder | retainer 4 is narrow compared with the conventional one, the volume of the useless space inside a bearing is small, and the usage-amount of a lubricant can be reduced, Lubricant is less likely to scatter to the outer periphery. In addition, since the lubricant is easily held inside the cage 4 (between the two cage pieces 4a and 4b), the slider 8 moves relative to the cage 4 more smoothly than in the prior art. be able to.

  Further, the force corresponding to the separating force acting on the two conventional sliders is received by the two retainer pieces 4a and 4b connected to each other. Therefore, by enlarging the cross-sectional area of the connecting portion of each cage piece 4a, 4b with little restriction in the radial direction, and making the both in direct contact and fastening with screws 9, the rigidity of the connecting portion is increased and torque is increased. The load capacity can be improved.

  FIG. 3 shows a second embodiment. In this embodiment, the shaft 3 and the slider 8 of the first embodiment are integrally formed. Thereby, the number of parts and the number of assembling steps can be reduced as compared with the first embodiment in which the shaft 3 and the slider 8 are separated from each other, and the torque load capacity can be expected to be improved by improving the strength of the rolling elements. Although illustration is omitted, not only the shaft 3 but also two shaft members 11 into which the rolling bearings 12 are fitted at both ends may be integrally formed with the slider 8.

Partially cutaway 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 Partially cutaway side view of a conventional shaft coupling VV line sectional view of FIG.

Explanation of symbols

1, 2 Plate (Rotating member)
3 Shaft (cylindrical rolling element)
4 Cage 4a, 4b Cage piece 5, 6 Guide groove 7 Long hole 8 Slider 9 Screw 10 Rolling bearing 11 Shaft member 12 Rolling bearing 13 Linear motion bearing A Input shaft B Output shaft

Claims (4)

  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 the shaft coupling provided with a slider for transmitting power, projecting in a bowl shape from the outer periphery of the rolling element, and engaging the retainer to restrain the rotation in a plane including the axis of the rolling element, the holding Two cage pieces arranged at positions sandwiching the slider Shaft coupling being characterized in that the a concatenation.   The shaft coupling according to claim 1, wherein a linear motion bearing is interposed between the slider and each cage piece.   The shaft coupling according to claim 1 or 2, wherein the slider and the rolling element are integrally formed.   The shaft coupling according to any one of claims 1 to 3, wherein any one of a screw, a retaining ring, caulking, and welding is adopted as means for connecting the two cage pieces.

Images