JP2008215429A - Magnetic power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce weight and manufacturing cost, even when a desired moving distance is large. <P>SOLUTION: A magnet body 33 of a base member 30 is constituted so as to have the predetermined reference length X along the axis C of a shaft-like member 20. A magnet body 22 of the shaft-like member 20 has a pair of side part magnetic bodies 22 mutually adjacent by sandwiching at least an optional central magnet body 22. When the shaft-like member 20 and the base member 30 relatively move in the axial direction of the shaft-like member 20, an end surface 22a positioned on one end part side of the shaft-like member 20 on one side part magnet body 22, deviates from an area opposed to the magnet body 33 of the base member 30, and at the same time, an end surface 22a positioned on one end part side of the shaft-like member 20 in the other side part magnetic body 22, is arranged at an equal interval by securing a predetermined clearance between mutual ones in a mode of entering the area opposed to the magnet body 33 of the base member 30. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a magnetic power transmission device that transmits power between the rotational movement of a shaft-like member and the reciprocation of a base member by the magnetic force between the magnet body of the shaft-like member and the magnet body of the base member. Is.

  An example of this type of magnetic power transmission device is disclosed in Patent Document 1. In this Patent Document 1, a shaft-like member disposed so as to be rotatable about its own axis, reciprocating along the axis of the shaft-like member, and rotating around the axis of the shaft-like member. A base member that is inserted into the shaft-shaped member in a restricted state, and transmits power between the shaft-shaped member and the base member. The outer peripheral surface of the shaft-shaped member and the inner peripheral surface of the base member The spiral permanent magnets are provided at the same pitch in such a manner as to face each other. The permanent magnet of the shaft-like member and the permanent magnet of the base member have different magnetic poles, and an attractive force acts by the magnetic force between them.

  In this magnetic power transmission device, for example, when the shaft-shaped member is rotated around its axis by a drive source such as an electric motor, the permanent magnet of the shaft-shaped member is rotated relative to the permanent magnet of the base member. Therefore, the base member moves in one direction along the screwing direction of the permanent magnet by the mutual attractive force. If the rotation direction of the shaft-shaped member is changed, the screwing direction is reversed, so that the movement direction of the base member with respect to the shaft-shaped member is also reversed.

  According to this type of magnetic power transmission device, since the shaft member and the base member are not in direct contact with each other, the noise during operation is extremely low, both do not wear, and damage occurs even when there is excessive input. There are advantages such as no fear of coming.

Japanese Patent No. 2777131

  By the way, in this type of magnetic power transmission device, at least one of the shaft-like member or the base member needs to have a length that is sufficiently longer than a desired movement distance. For example, in what is described in Patent Document 1, the total length of the shaft-shaped member is configured to be sufficiently large with respect to the base member, and by moving the base member along this shaft-shaped member, a desired value can be obtained. Trying to get the distance traveled.

  However, in the configuration described in Patent Document 1, in order to move the base member over the entire length of the shaft-shaped member, permanent magnets must be configured on all of the shaft-shaped members, and when manufacturing costs are considered, It is not necessarily preferable. In addition, in the case where the permanent magnet is constituted over the entire length of the shaft-shaped member, the weight thereof must be extremely large.

  In view of the above circumstances, an object of the present invention is to provide a magnetic power transmission device capable of reducing the weight and manufacturing cost even when a desired moving distance is large.

  In order to achieve the above object, a magnetic power transmission device according to claim 1 of the present invention is provided with a magnet body in which a permanent magnet is formed in a spiral shape around its own axis on the outer peripheral surface. A shaft-shaped member disposed rotatably around the center, and a magnet body in which a plurality of permanent magnets are arranged in parallel along the axial direction of the shaft-shaped member at a facing portion facing the outer peripheral surface of the shaft-shaped member. And a base member arranged so as to be able to reciprocate linearly along the axial direction of the shaft-shaped member, and rotation of the shaft-shaped member by the magnetic force between the magnet body of the shaft-shaped member and the magnet body of the base member A magnetic power transmission device for transmitting power between movement and reciprocation of a base member, wherein one of the magnet body of the shaft member and the magnet body of the base member is a shaft of the shaft member It is configured to have a predetermined reference length along the center, and the shaft shape The other of the magnet body of the material and the magnet body of the base member includes a pair of side magnet bodies adjacent to each other with at least an arbitrary central magnet body, and the shaft-shaped member and the base member are the shaft-shaped member. When one side magnet body moves relatively along the axial direction, an end surface portion located on one end side of the shaft-like member deviates from a region facing the magnet body of the base member and at the same time the other side portion. In the magnet body, the end face portion located on one end side of the shaft-like member enters the region facing the magnet body of the base member, and a predetermined gap is secured between them and arranged at equal intervals. It is characterized by that.

  A magnetic power transmission device according to a second aspect of the present invention is the magnetic power transmission device according to the first aspect, wherein the base member is provided with a magnet body having a reference length, and the shaft-like member is provided with a plurality of magnet bodies at equal intervals. It was set up.

  According to a third aspect of the present invention, there is provided the magnetic power transmission device according to the first aspect, wherein the magnet body formed on the base member has a semi-cylindrical concave surface centered on the axis of the shaft-shaped member. It is characterized by having.

  According to the present invention, with respect to the magnet body of the reference length provided on one of the shaft-like member and the base member, a gap is secured between each other in such a manner that the other magnet body always faces two. As a result, the number of the other magnet bodies can be reduced as much as possible, and power can be reliably transmitted without causing step-out between the two. As a result, even when a desired moving distance is large, it is possible to reduce the weight and reduce the manufacturing cost.

  Exemplary embodiments of a magnetic power transmission device according to the present invention will be explained below in detail with reference to the accompanying drawings.

  1 to 3 show a magnetic actuator to which a magnetic power transmission device according to the present invention is applied. The magnetic actuator illustrated here is applied as a drive source for positioning a work table that holds a work, which is a workpiece, in a machine tool, for example, with respect to a tool, and includes an actuator body 10. The actuator body 10 includes a pair of bearing plates 11 and a pair of side plates 12 spanned between the bearing plates 11 and is configured in a rectangular parallelepiped shape. The bearing plates 11 are flat plate members each having a rectangular shape, and are provided so as to be parallel to each other. The side plates 12 extend so as to be parallel to each other from edges located on the left and right sides of the bearing plate 11 in FIG.

  Moreover, this magnetic actuator is provided with the shaft-shaped member 20 and the guide rail member 13 as shown in FIGS.

  The shaft-like member 20 has a columnar shape having an overall length larger than the distance between the pair of bearing plates 11, and each end portion penetrates the center portion of the bearing plate 11 and has its own axis. It is constructed between the bearing plates 11 in such a manner that it can rotate.

  The shaft-like member 20 is provided with a plurality of large diameter portions 21. The large-diameter portion 21 is a cylindrical portion that bulges radially outward about the axis C of the shaft-shaped member 20, and is provided at positions that are equidistant from each other along the axial direction of the shaft-shaped member 20. is there.

  The guide rail member 13 is the only flat plate member that spans between the pair of bearing plates 11, and is provided between the edges located below the bearing plate 11 in FIG. As is clear from FIGS. 1 to 3, the guide rail member 13 is configured to have a width smaller than the distance between the pair of side plates 12, and a gap is secured between each side plate 12 and the shaft. It extends in a mode along the axial direction of the shaped member 20.

  As shown in FIGS. 1 to 3, the guide rail member 13 is provided with a base member 30 at a portion between the pair of side plates 12. The base member 30 includes a slide base 31 and a pair of support plates 32.

  The width of the slide base 31 in the direction perpendicular to the axis C of the shaft-shaped member 20 is larger than that of the guide rail member 13, and the length along the axis direction of the shaft-shaped member 20 is longer than that of the side plate 12 of the actuator body 10. Is also a small flat plate member, and has a pair of rail guides 31a on its outer surface. The rail guide 31a protrudes from the slide base 31 in a state in which a gap that allows the guide rail member 13 to be fitted between the rail guides 31a is secured. The slide base 31 is disposed between the pair of side plates 12 with the guide rail member 13 disposed between a pair of rail guides 31 a and the outer surface thereof being in contact with the guide rail member 13. Yes, it is possible to reciprocate along the axial direction of the shaft-shaped member 20 using the guide rail member 13 as a guide.

  The pair of support plates 32 are flat plate-like members erected in such a manner that they are parallel to each other from both side edges of the slide base 31. As shown in FIGS. 2 and 3, these support plates 32 are arranged on the slide base 31 so that the inner surfaces facing each other cover the outer peripheral surface of the shaft-shaped member 20 and the distance from the shaft-shaped member 20 is the same. It is attached.

  Further, in the magnetic actuator, magnet bodies 22 and 33 are formed on the outer peripheral surface of the large-diameter portion 21 of the shaft-shaped member 20 and the inner surfaces of the pair of support plates 32, respectively.

  As shown in FIG. 4, the magnet body of the shaft-shaped member 20 (hereinafter referred to as “shaft magnet body 22”) is helically formed on the outer peripheral portion of the large-diameter portion 21 around the axis C of the shaft-shaped member 20. It is a thing. In the present embodiment, the first permanent magnet 22A and the second permanent magnet 22B are wound so as to draw two spirals at a constant regular pitch in a manner in which the magnetic poles appearing on the outer peripheral surface are different from each other, so that a plurality of thick magnets can be obtained. A shaft magnet body 22 is formed in each of the diameter portions 21. Each of the first permanent magnet 22A and the second permanent magnet 22B is configured by previously magnetizing a magnetic material. In the present embodiment, the inclination angle α of the spiral drawn by each permanent magnet 22A, 22B of the shaft magnet body 22 with respect to the axis C of the shaft-shaped member 20 is 45 °.

  As shown in FIG. 5, the magnet body of the support plate 32 (hereinafter referred to as “support magnet body 33”) has linear first permanent magnets 33A and second permanent magnets 33B in such a manner that the magnetic poles appearing on the outer surface are different from each other. Are arranged in parallel along the axial direction of the shaft-shaped member 20. Each permanent magnet 33A, 33B has a shaft magnet of the large-diameter portion 21 so as to face the permanent magnet 22A, 22B of the shaft magnet body 22 formed on the large-diameter portion 21 of the shaft-shaped member 20 on a one-to-one basis. The pitch is substantially the same as that of the body 22 and the tilt angle β is 45 ° with respect to the axis C of the shaft member 20.

  Further, as shown in the detailed configuration of FIG. 6, the support magnet body 33 configured on one support plate 32 and the support magnet body 33 configured on the other support plate 32 include a large-diameter portion 21 of the shaft-shaped member 20. They are offset in different directions from each other with respect to the shaft magnet body 22 configured as described above. That is, in the support plate 32 located in the upper part of FIG. 6, the permanent magnets 22 </ b> A and 22 </ b> B of the shaft magnet body 22 formed in the large diameter portion 21 are offset to the right along the axis C of the shaft-shaped member 20. Thus, permanent magnets 33A and 33B are arranged in parallel. On the other hand, in the support plate 32 located in the lower part of FIG. 6, on the left side along the axis C of the shaft-shaped member 20 with respect to the permanent magnets 22A and 22B of the shaft magnet body 22 formed in the large diameter portion 21. Permanent magnets 33A and 33B are arranged in parallel so as to be offset.

  Here, as described above, the permanent magnets 33A and 33B of the support magnet body 33 formed on the support plate 32 and the permanent magnets 22A and 22B of the shaft magnet body 22 formed on the large-diameter portion 21 of the shaft-shaped member 20 are When the central axes of each other are offset along the axial direction of the shaft-shaped member 20, as shown in FIG. 7, the magnetic attractive force along the axial direction of the shaft-shaped member 20 according to the offset amount. (Magnetic biasing force) will act.

  Specifically, as shown on the right side of FIG. 7, when the permanent magnet of the shaft magnet body 22 is offset to the right with respect to the permanent magnet of the support magnet body 33, A magnetic attraction force F that moves the support plate 32 in the right direction acts on the shaft-like member 20 so that the central axes of the support magnet body 33 and the permanent magnet coincide with each other. In contrast, as shown on the left side of FIG. 7, when the permanent magnet of the shaft magnet body 22 is offset to the left side with respect to the permanent magnet of the support magnet body 33, the permanent magnet and the support of the shaft magnet body 22 are supported. Magnetic attraction force −F (force toward the right side in FIG. 7) that moves the support plate 32 leftward relative to the shaft-like member 20 so that the central axes of the magnet body 33 and the permanent magnet coincide with each other. Act as positive). The magnitude of the magnetic attractive force acting between the permanent magnet of the shaft magnet body 22 and the permanent magnet of the support magnet body 33 gradually increases as the offset amount increases, and then gradually decreases as the offset amount increases. To come.

  In the present embodiment, the permanent magnets 33A of the support magnet body 33 configured on one support plate 32 with respect to the arbitrary permanent magnets 22A and 22B of the shaft magnet body 22 configured on the large diameter portion 21 of the shaft-shaped member 20. The magnetic attractive force acting between 33B and the magnetic attractive force acting between the permanent magnets 33A, 33B of the supporting magnet body 33 formed on the other supporting plate 32 is almost the maximum value and is axial. The permanent magnets 22A, 22B, 33A, 33B are offset and arranged so as to act in opposite directions along the axial direction of the member 20. Although not clearly shown in the figure, the number of permanent magnets 33A and 33B of the support plate 32 facing the permanent magnets 22A and 22B of the shaft magnet body 22 is the same in one support plate 32 and the other support plate 32. Each dimension is set so that That is, the permanent magnets 33A and 33B of the support magnet body 33 are opposed to the permanent magnets 22A and 22B of the shaft magnet body 22 between the one support plate 32 (first facing position) and the other. The permanent magnets 33 </ b> A and 33 </ b> B of the support magnet body 33 oppose each other (second opposing position).

  As shown in FIG. 3, the support magnet body 33 of the support plate 32 and the shaft magnet body 22 of the shaft-shaped member 20 always have two shafts when the support plate 32 is reciprocated relative to the shaft-shaped member 20. Each dimension is set so that only the magnet body 22 faces the support magnet body 33 of the support plate 32. More specifically, when the length along the axial center direction of the shaft-shaped member 20 in the support magnet body 33 of the support plate 32 is the reference length X, an arbitrary shaft magnet body 22 (hereinafter referred to as “ In a pair of shaft magnet bodies 22 (hereinafter referred to as “side magnet bodies” as appropriate) that are adjacent to each other across the “center magnet body”), the distance between the end faces 22a positioned on one end side of the shaft-like member 20 is The support magnet body 33 of the support plate 32 and the shaft magnet body 22 of the shaft-like member 20 are configured to match the reference length X, respectively. That is, when the shaft-shaped member 20 and the base member 30 move relatively along the axial center direction of the shaft-shaped member 20, the end surface 22a of one side magnet body 22 is based on the central magnet body 22 as a base. While deviating from the region facing the support magnet bodies 33, 33 of the member 30, the end surface 22 a of the other side magnet body 22 enters the region facing the support magnet bodies 33, 33 of the base member 30 and at the same time A predetermined gap is secured at equal intervals.

  In the magnetic actuator configured as described above, for example, each permanent magnet of the shaft magnet body 22 that forms the spiral shape of the shaft member 20 with respect to the permanent magnets 33A and 33B that form the support magnet bodies 33 and 33 of the base member 30. The state where 22A and 22B face each other different magnetic poles is the drive standby state. When the shaft-like member 20 is rotated in one direction around its axis by a drive source such as an electric motor (not shown) in a state where the movement of the actuator main body 10 is restricted from the drive standby state, for example, the support magnet of the base member 30 The shaft magnet body 22 that forms the spiral shape of the shaft-shaped member 20 is screwed with respect to the bodies 33 and 33. Since the base member 30 is in contact with the guide rail member 13 via the slide base 31, the rotation of the shaft-like member 20 around the axis is restricted. As a result, due to the magnetic attractive force acting between the supporting magnet body 33 of the base member 30 and the shaft magnet body 22 of the shaft-shaped member 20, the base member 30 is shaft-shaped with respect to the shaft-shaped member 20 and the actuator body 10. It will move in one direction along the 20 axis direction. If the rotation direction of the shaft-like member 20 is changed, the screwing direction of the helical shaft magnet body 22 is reversed, so that the movement direction of the base member 30 with respect to the shaft-like member 20 is also reversed. Therefore, for example, if the actuator body 10 is held by the fixed body and the base member 30 is held by the work table, the work table can be reciprocated by the rotation of the electric motor and can be arranged at an arbitrary position.

  Here, in the magnetic actuator described above, the permanent magnets 22A and 22B constituting the shaft magnet body 22 of the shaft-like member 20 and the permanent magnets 33A and 33B constituting the support magnet body 33 of the base member 30 are offset from each other. The directions of the magnetic attractive forces acting between the permanent magnets 22A, 22B, 33A, 33B facing each other are opposite to each other along the axial direction of the shaft-like member 20 at a plurality of opposing positions corresponding to each other. It is configured to be oriented. Therefore, the shaft-like member 20 and the base member 30 always stop at a position where the opposite electromagnetic attracting forces are balanced, and maintain that position. Accordingly, if the rotation of the shaft-like member 20 is stopped, the movement of the base member 30 is also immediately stopped and the position thereof is maintained accordingly, and the positioning accuracy of both can be improved.

  In this case, it is not necessary to precisely define the dimensions of the permanent magnets 22A and 22B constituting the shaft magnet body 22 of the shaft-shaped member 20 and the permanent magnets 33A and 33B constituting the support magnet body 33 of the base member 30, and simply The magnetic attractive force acting in the reverse direction may be balanced. Accordingly, there is no need to match the widths of the permanent magnets 22A and 22B constituting the shaft magnet body 22 of the shaft-like member 20 and the permanent magnets 33A and 33B constituting the support magnet body 33 of the base member 30. Manufacturing operations can be facilitated.

  Moreover, since the shaft member 20 and the base member 30 are not in direct contact with each other, the noise when the base member 30 moves is extremely small, the two members do not wear, and damage is caused even if there is an excessive input. There are advantages such as no fear.

  Further, according to the magnetic actuator, only the two shaft magnet bodies 22 always face the support magnet body 33 of the support plate 32 with respect to the support magnet body 33 of the reference length X provided on the base member 30. Each dimension is set. Therefore, although the total length of the shaft-like member 20 corresponds to the reciprocation distance with respect to the desired reciprocation distance of the base member 30, the number of the shaft magnet bodies 22 provided on the shaft-like member 20 can be as large as possible. Can be reduced. As a result, even when a large moving distance is required for the magnetic actuator, the weight can be reduced and the manufacturing cost can be reduced. In this case, since the two shaft magnet bodies 22 always face the support magnet body 33 of the support plate 32 regardless of the overall length of the shaft member 20, the rotational movement of the shaft member 20 and the support plate 32 There is no possibility of incurring a situation where the reciprocating movement is out of step and deviated.

  In the above-described embodiment, the power transmission device applied to the magnetic actuator that reciprocates the base member when the shaft-like member is rotated is illustrated, but the present invention is not limited to this. . For example, the present invention can be applied to a structure in which a shaft member is rotated by reciprocating a base member with a drive source such as a cylinder actuator.

  In the above-described embodiment, since the pair of magnet bodies are provided in a manner parallel to the base member with respect to the magnet body of the shaft-shaped member, the magnet body of the shaft-shaped member and the base member Although it becomes possible to improve the power transmission efficiency during irradiation without applying a bending force to the shaft-like member due to the magnetic force between the magnet body, the magnet body of the base member does not necessarily have to be a pair, Needless to say, the magnet body of the shaft member and the magnet body of the base member need not be offset.

  Furthermore, in the above-described embodiment, as shown in FIG. 6, the magnetic material configured as the shaft-shaped member is smaller in width than the magnetic material configured as the base member. However, the present invention is not limited thereto, and the width of the magnetic body formed on the shaft-like member may be larger than the width of the magnetic body formed on the base member, or both may be the same width (not necessarily exactly the same). It does not have to be configured).

  In the above-described embodiment, when performing power transmission between the cylindrical shaft-shaped member and the flat plate-shaped base member, the cylindrical magnetic material provided on the large-diameter portion of the shaft-shaped member. Although a flat plate-like magnetic body is disposed on the support plate of the base member with respect to the outer peripheral surface of the base plate, for example, if it is configured as in the modification shown in FIG. 8, the power transmission efficiency between the two is further increased. It is possible.

  That is, in the modification of FIG. 8, a support magnet body 133 having a semi-cylindrical concave surface 133 a is disposed on the support plate 132 of the base member 130, and the concave surface 133 a is configured as the large diameter portion 21 of the shaft-shaped member 20. The shaft magnet body 22 is made to face. The base member 130 of the modified example shown in FIG. 8 includes a slide base 131 and a pair of support plates 132, as in the embodiment. The slide base 131 has a guide rail member 13 disposed between a pair of rail guides 131a, and the outer surface of the slide base 131 is in contact with the guide rail member 13, and guides the guide rail member 13. As described above, it is possible to reciprocate along the axial direction of the shaft-shaped member 20. As in the embodiment, the shaft-shaped member 20 has a large-diameter portion 21, and the shaft magnet body 22 is spirally formed on the outer peripheral portion of the large-diameter portion 21. The concave surface 133 a of the support magnet body 133 is formed around the axis C of the shaft-shaped member 20, and is constant with respect to the outer peripheral surface of the shaft magnet body 22 formed in the large-diameter portion 21 of the shaft-shaped member 20. It is arranged at a position where the gap is secured.

  According to the magnetic actuator of the modified example configured as described above, the facing area between the shaft magnet body 22 of the shaft-shaped member 20 and the support magnet body 133 of the base member 130 is increased. In addition to the function and effect produced by this embodiment, the power transmission efficiency between the two can be improved.

  In the modified example of FIG. 8, the support magnet body 133 has a semi-cylindrical concave surface 133a. However, the semi-cylindrical concave surface 133a is not necessarily required. There is no. In addition, the concave surface of the support magnet body 133 is not necessarily configured by a single magnetic body, and a cylindrical concave surface may be configured as a plurality of aggregates.

1 is a perspective view of a magnetic actuator to which a magnetic power transmission device according to an embodiment of the present invention is applied. It is a cross-sectional view of the magnetic actuator shown in FIG. It is a principal part top view of the magnetic actuator shown in FIG. It is a conceptual diagram which shows typically the arrangement | positioning aspect of the magnetic body comprised on the shaft-shaped member of the magnetic actuator shown in FIG. It is a conceptual diagram which shows typically the arrangement | positioning aspect of the magnetic body comprised in the shaft-shaped member and base member of the magnetic actuator shown in FIG. It is a conceptual diagram for demonstrating in detail the arrangement | positioning aspect of the magnetic body comprised in the shaft-shaped member and base member of the magnetic actuator shown in FIG. 2 is a graph showing a relationship between a magnetic force acting between a shaft-like member and a base member in the magnetic actuator shown in FIG. FIG. 6 is a cross-sectional view of a main part showing a modification of the magnetic actuator shown in FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Actuator main body 20 Shaft-shaped member 21 Large diameter part 22 Magnet body 22A, 22B Permanent magnet 30 Base member 31 Slide base 32 Support plate 33 Support magnet body 33A, 33B Permanent magnet C Shaft center of shaft-shaped member

Claims (3)

A shaft-shaped member provided on the outer peripheral surface with a magnet body helically configured with a permanent magnet centered on its own axis, and rotatably arranged around its own axis;
A magnet body in which a plurality of permanent magnets are arranged in parallel along the axial direction of the shaft-shaped member is provided at a portion facing the outer peripheral surface of the shaft-shaped member, and is linearly reciprocated along the axial direction of the shaft-shaped member. And a base member arranged as possible, and the transmission of power between the rotational movement of the shaft-shaped member and the reciprocating movement of the base member by the magnetic force between the magnet body of the shaft-shaped member and the magnet body of the base member. A magnetic power transmission device for performing
Either one of the magnet body of the shaft-shaped member and the magnet body of the base member is configured to have a predetermined reference length along the axis of the shaft-shaped member,
The other of the magnet body of the shaft-shaped member and the magnet body of the base member includes a pair of side magnet bodies adjacent to each other with at least an arbitrary central magnet body sandwiched between the shaft-shaped member and the base member. When the one side magnet body moves relatively along the axial direction of the cylindrical member, the end surface portion located on the one end side of the axial member deviates from the region facing the magnet body of the base member and at the same time the other In the aspect in which the end surface portion located on one end portion side of the shaft-like member enters the region facing the magnet body of the base member in the side magnet body, a predetermined gap is secured between each other and arranged at equal intervals. A magnetic power transmission device characterized by that.   2. The magnetic power transmission device according to claim 1, wherein a magnet body having a reference length is provided on the base member, and a plurality of magnet bodies are arranged on the shaft-like member at equal intervals.   2. The magnetic power transmission device according to claim 1, wherein the magnet body configured in the base member has a semi-cylindrical concave surface centering on an axis of the shaft-shaped member.

Images