JP2011047434A - Pulley structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulley structure preventing the resonance of two rotors magnetically connected to each other by suppressing the occurrence of torque when a rotating speed difference (a phase difference) between the two rotors is small. <P>SOLUTION: A plurality of first magnets 17 with center angles equal to one another are provided on a hub 3, and arranged across magnetic bodies in the peripheral direction. A plurality of second magnets 18 as two types of magnets, namely, magnets 18a with center angles equal to those of the first magnets 17 and magnets 18b with center angles greater than those of the first magnets 17 are provided on a pulley 2, and the two types of magnets are arranged alternately in the peripheral direction. The faces of the two first magnets 17 neighboring each other in the peripheral direction, opposite to the second magnets 18, have mutually reverse magnetic poles. The faces of the two second magnets 18 neighboring each other in the peripheral direction, opposite to the first magnets 17, have mutually reverse magnetic poles. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pulley structure having two rotating bodies capable of relative rotation.

  Conventionally, as a pulley structure having two rotating bodies connected so as to be relatively rotatable, when a rotational fluctuation occurs in one of the two rotating bodies, a structure having a configuration for attenuating the rotational fluctuation is provided. Are known.

  For example, a pulley structure described in Patent Document 1 includes a pulley around which a belt is wound, and a hub that is provided inside the pulley so as to be relatively rotatable with respect to the pulley and is connected to an output shaft of an engine. And a rubber elastic body (rubber coupling) for connecting the pulley and the hub. When the rotation fluctuation occurs in the hub in accordance with the engine torque fluctuation, the rubber elastic body between the hub and the pulley is elastically deformed to absorb the rotation fluctuation.

  There has also been proposed a pulley structure in which two rotating bodies are connected by a magnetic force without using a rubber elastic body. For example, the pulley structure described in Patent Document 2 includes a pulley around which a belt driven by an output shaft of an engine is wound, and a cylindrical shaft that is arranged inside the pulley and is connected to an alternator. A plurality of magnets arranged in the circumferential direction are provided on the inner surface of the pulley, and a plurality of magnets arranged in the circumferential direction are also provided on the outer surface of the cylindrical shaft. In addition, the plurality of magnets provided on the pulley and the cylinder shaft are both arranged so that the magnetic poles alternately change in the circumferential direction, and by the magnetic force in the attracting direction that acts when magnets of different polarities face each other, The pulley and the cylinder shaft are connected. In this pulley structure, when the rotational fluctuation is transmitted from the output shaft of the engine to the pulley via the belt, the rotational fluctuation is absorbed by shifting the rotational phase of the pulley coupled by the magnetic force and the cylindrical shaft.

Japanese Utility Model Publication No. 63-68540 Japanese Patent Laying-Open No. 2006-9898 (FIG. 2)

  However, when two rotating bodies are connected by a rubber elastic body as in the pulley structure of Patent Document 1, a failure due to aged deterioration or fatigue failure of the rubber elastic body occurs. In addition, when an excessive rotation fluctuation occurs in one of the rotating bodies, an excessive force exceeding the elastic deformation range acts on the rubber elastic body, and the rubber elastic body may be damaged. Furthermore, the pronunciation of the rubber elastic body during elastic deformation may be a problem.

  On the other hand, in the configuration in which two rotating bodies are coupled by magnetic force as in the pulley structure of Patent Document 2, the above-described problem does not occur because the rubber elastic body is not used. However, in the pulley structure of Patent Document 2, a small rotational fluctuation occurs and the phases of the two rotating bodies are slightly shifted, so that the plurality of magnets provided on one rotating body and the other rotating body Magnets with the same polarity face each other and a large repulsive force is generated between a plurality of provided magnets, and the torque acting on the two rotating bodies in a direction to eliminate the phase difference (rotational speed difference) is very large. It will be a thing. As described above, if the torque acting in the direction of eliminating the phase difference is too large for a small phase difference, resonance may occur between the two rotating bodies.

  An object of the present invention is to connect two rotating bodies by a magnetic force and suppress a torque generated when the rotational speed difference (phase difference) between the two rotating bodies is small, thereby preventing resonance. Is to provide a body.

Means for Solving the Problems and Effects of the Invention

A pulley structure according to a first aspect of the present invention is provided on one of a first rotating body, a second rotating body that can rotate relative to the first rotating body, and the first rotating body and the second rotating body. A plurality of first magnets arranged along the circumferential direction, and a plurality of first magnets arranged along the circumferential direction, provided on the other of the first rotating body and the second rotating body so as to face the first magnet. Second magnet,
The plurality of first magnets have a central angle equal to each other, the plurality of first magnets are arranged with a magnetic body sandwiched in the circumferential direction, and the plurality of second magnets are magnets having the same central angle as the first magnet. And a magnet having a larger central angle than the first magnet, and the two types of magnets are alternately arranged in the circumferential direction,
Further, the magnetic poles on the surface facing the second magnet are opposite between the two first magnets adjacent in the circumferential direction, and the second magnet is also between the two second magnets adjacent in the circumferential direction. The magnetic poles on the surface facing one magnet are opposite to each other.

  According to the configuration of the present invention, the first magnet provided on one of the first rotating body and the second rotating body, and the second magnet provided on the other of the first rotating body and the second rotating body, the first magnet The rotating body and the second rotating body are connected in a state in which relative rotation is possible. When a rotational fluctuation occurs in one rotating body and a rotational speed difference (phase shift, phase difference) occurs between the two rotating bodies, the magnetic force acting between the first magnet and the second magnet Torque acts between the first rotating body and the second rotating body so as to eliminate the rotational speed difference. Thereby, the rotation fluctuation produced in one rotating body is attenuated.

  According to this configuration, since the rubber elastic body is not used to attenuate the rotational fluctuation, problems such as aging deterioration and fatigue destruction of the rubber elastic body or sound generation at the time of elastic deformation of the rubber elastic body do not occur.

  In the present invention, the plurality of first magnets have the same center angle, and the plurality of first magnets are arranged in the circumferential direction with the magnetic material interposed therebetween. On the other hand, the plurality of second magnets are composed of two types of magnets, a magnet having the same central angle as the first magnet and a magnet having a larger central angle than the first magnet, and these two types of magnets are in the circumferential direction. Are alternately arranged. Furthermore, the magnetic poles of the opposing surfaces are reversed between two adjacent magnets in both the plurality of first magnets and the plurality of second magnets. Therefore, when a relatively small rotational speed difference (phase difference) is generated between the first rotating body and the second rotating body, the phases of the plurality of first magnets and the plurality of second magnets are slightly shifted from each other. The second magnet having a large angle is partially opposed to the first magnet having the same magnetic pole on the opposite surface, but the second magnet having a small central angle (equal to the first magnet and the central angle) is the first magnet. It faces the magnetic body located between them and does not face the first magnet of the same polarity. Therefore, the repulsive magnetic force acting between the plurality of first magnets and the plurality of second magnets is relatively small. That is, when the rotational speed difference (phase difference) between the two rotating bodies is small, the torque that acts to eliminate this rotational speed difference is small, so that resonance occurs between the first rotating body and the second rotating body. It can be prevented from occurring.

  Further, when the magnetic poles on the opposing surfaces of the plurality of first magnets and the plurality of second magnets are the same between the magnets adjacent in the circumferential direction (that is, the magnetization direction is the same), the magnets between the adjacent magnets Due to the repulsive force that acts, it is difficult to arrange the first magnet and the second magnet in the circumferential direction. In the present invention, since the magnetic poles on the opposing surfaces are reversed between the magnets adjacent in the circumferential direction, the arrangement of the magnets is facilitated.

  A pulley structure according to a second invention is the pulley structure according to the first invention, wherein at least one of the plurality of first magnets and the plurality of second magnets is made of a magnetic material on a surface opposite to the facing surface. A yoke is provided.

  According to this configuration, leakage of magnetic flux is suppressed from the surface opposite to the opposing surface of the first magnet and the second magnet, and the magnetic energy generated by the first magnet and the second magnet is reduced between the first magnet and the second magnet. Therefore, torque can be efficiently transmitted between the first rotating body and the second rotating body.

  The pulley structure according to a third aspect of the present invention is characterized in that, in the first or second aspect of the invention, the plurality of first magnets and the plurality of second magnets each constitute an annular magnet body. To do.

  According to this configuration, since the plurality of first magnets and the plurality of second magnets are arranged over the entire circumference, the torque acts evenly in the circumferential direction between the first rotating body and the second rotating body. Can be made.

It is a schematic structure figure of an auxiliary machinery drive system concerning an embodiment of the present invention. It is sectional drawing regarding the surface containing the rotating shaft of a pulley structure. It is a perspective view of the annular magnet body arrange | positioned between a pulley and a hub. (A) is the figure which looked at the 1st annular magnet body from the rotation axis direction, (b) is the figure which looked at the 2nd annular magnet body from the rotation axis direction. It is a figure which shows the positional relationship of a 1st magnet and a 2nd magnet when there is no rotational speed difference between a pulley and a hub. It is a figure which shows the positional relationship of a 1st magnet and a 2nd magnet when there exists a small rotational speed difference between a pulley and a hub. It is a figure which shows the positional relationship of a 1st magnet and a 2nd magnet when there exists a big rotational speed difference between a pulley and a hub. It is sectional drawing regarding the surface containing a rotating shaft of the pulley structure which concerns on a change form. It is sectional drawing regarding the surface containing a rotating shaft of the pulley structure of another modification. It is the figure which looked at the annular magnet body of the pulley structure of FIG. 9 from the rotation axis direction. It is a graph which shows the relationship between the rotation angle of the pulley structure of Examples 1-4 and the comparative example 1, and a torque. It is a graph which shows the relationship between the rotation angle of the pulley structure of Examples 5-8 and the comparative example 2, and a torque.

  Next, an embodiment of the present invention will be described. This embodiment is an example in which the present invention is applied to a pulley structure used in an accessory drive system that drives an accessory by the torque of the output shaft of an automobile engine.

  FIG. 1 is a schematic configuration diagram of an auxiliary machine drive system according to this embodiment. As shown in FIG. 1, an accessory drive system 100 includes a drive pulley 105 connected to an engine output shaft 101 (a reciprocating engine crankshaft, a rotary engine eccentric shaft, etc.), and various types such as a water pump and an alternator. Drive shafts (auxiliary shafts) 102 and 103 respectively connected to the accessory, a driven pulley 104 attached to the driven shaft 102, and a pulley 2 of the pulley structure 1 according to the present embodiment attached to the driven shaft 103. And a drive pulley 105, a driven pulley 104, and a transmission belt 106 that spans the pulley 2 of the pulley structure 1. In the present embodiment, a V-ribbed belt having a plurality of V-ribs 106a extending in parallel with each other along the belt longitudinal direction is used as the transmission belt 106 (see FIG. 2).

  When the drive pulley 105 is rotationally driven by the torque of the output shaft 101, the transmission belt 106 is driven by the rotation of the drive pulley 105. Then, as the transmission belt 106 travels, the driven pulley 104 and the pulley 2 of the pulley structure 1 are driven to rotate, so that auxiliary equipment such as a water pump and an alternator connected to the driven shafts 102 and 103 is obtained. Each is driven.

  Next, the pulley structure 1 of this embodiment that transmits torque transmitted from the output shaft 101 via the transmission belt 106 to the driven shaft (auxiliary shaft) 103 will be described in detail. FIG. 2 is a cross-sectional view relating to the plane including the rotation axis C of the pulley structure 1 of the present embodiment. As shown in FIG. 2, the pulley structure 1 includes a cylindrical pulley 2 around which the transmission belt 106 is wound, and a hub 3 connected to a driven shaft (auxiliary shaft) 103 and provided inside the pulley 2. It has. The pulley 2 and the hub 3 correspond to the first rotating body and the second rotating body in the present invention. The pulley 2 and the hub 3 are connected to each other via a bearing 5 so as to be relatively rotatable. The right side in FIG. 2 is defined as the distal end side of the pulley structure 1 and the left side in FIG. 2 (the driven shaft (auxiliary shaft) 103 side) is defined as the proximal end side of the pulley structure 1 and will be described below.

  A plurality of V grooves 11 extending along the circumferential direction are formed on the outer peripheral portion of the pulley 2. The transmission belt 106 is wound around the outer circumference of the pulley 2 with a plurality of V ribs 106 a formed on the abdominal surface side engaged with the plurality of V grooves 11.

  The hub 3 has two cylindrical members 3a and 3b arranged coaxially along the rotation axis direction, and these two cylindrical members 3a and 3b are connected and integrated in a portion not shown. The distal end portion of the driven shaft 103 is fitted into the two cylindrical members 3a and 3b of the hub 3, and the driven shaft 103 and the hub 3 are connected so as not to be relatively rotatable by appropriate connecting means such as bolts. The two cylindrical members 3a and 3b constituting the pulley 2 and the hub 3 are each made of a nonmagnetic material (paramagnetic material, diamagnetic material, or antiferromagnetic material). Examples of the nonmagnetic material include austenitic stainless steel, aluminum alloy, titanium alloy, and synthetic resin.

  Of the two cylindrical members 3a and 3b, the cylindrical member 3a located on the proximal end side is provided with a bearing 5, and the pulley 2 is rotatably connected to the cylindrical member 3a via the bearing 5. On the other hand, an annular magnet housing chamber 16 is formed between the cylindrical member 3b located on the distal end side and the pulley 2, and two magnets 16 fixed to the cylindrical member 3b of the hub 3 are formed in the magnet housing chamber 16. The first annular magnet body 20 and one second annular magnet body 21 fixed to the pulley 2 are accommodated.

  3 is a perspective view of the annular magnet bodies 20 and 21 shown in FIG. 2, and FIGS. 4A and 4B are views of the annular magnet bodies 20 and 21 viewed from the direction of the rotation axis C of the pulley 2. FIG. . As shown in FIG. 2, the 1st annular magnet body 20 is being fixed to the hub 3 in the internal peripheral surface. As shown in FIGS. 3 and 4A, the first annular magnet body 20 is composed of six first magnets 17 and a magnetic body 25 made of six magnetic materials (preferably soft magnetic materials). The six first magnets 17 and the six magnetic bodies 25 are alternately arranged in the circumferential direction. That is, the six first magnets 17 are arranged in the circumferential direction with the magnetic body 25 interposed therebetween. 4A, both the first magnet 17 and the magnetic body 25 have a substantially fan shape, but the central angle α of the first magnet 17 is larger than the central angle β of the magnetic body 25. ing.

  As shown in FIG. 2, the 2nd annular magnet body 21 is being fixed to the pulley 2 in the outer peripheral surface. As shown in FIGS. 3 and 4, the second annular magnet body 21 includes six second magnets 18 arranged side by side in the circumferential direction. Furthermore, as shown in FIG. 4B, the six second magnets 18 are each formed in a substantially fan shape, but the center angles of these six second magnets 18 are not all the same, but the center angles are different. There are two types of magnets 18a, 18b. Of the two types of second magnets 18 a and 18 b, the central angle of one magnet 18 a is equal to the central angle α of the first magnet 17. The center angle of the other magnet 18b is larger than the center angle α of the first magnet 17, and is equal to an angle (α + 2β) obtained by adding the center angle β of the two magnetic bodies 25 to the center angle α.

  In addition, the 1st magnet 17 and the 2nd magnet 18 are comprised with the permanent magnet, respectively. As the permanent magnet, a material containing neodymium, samarium cobalt, ferrite, alnico, platinum, chromium, iron, manganese, aluminum, praseodymium, or the like can be used. Moreover, as a magnetic material which comprises the magnetic body 25, soft iron, a ferrite (Ni-Zn type ferrite, Mn-Zn type ferrite), etc. are mentioned. In addition, permalloy, sendust, permendur, silicon steel, etc. can be used.

  Also, the two first annular magnet bodies 20 fixed to the hub 3 and the one second annular magnet body 21 fixed to the pulley 2 are alternately arranged with a gap in the direction of the rotation axis C of the pulley 2. ing. In other words, the second annular magnet body 21 composed of the second magnet 18 is sandwiched between the first annular magnet body 21 composed of the first magnet 17 and the magnetic body 25 in the rotation axis direction. And the 2nd magnet 18 which comprises the 2nd annular magnet body 21 has each opposed the 1st magnet 17 of the 1st annular magnet body 20 located in both sides.

  Moreover, the 1st magnet 17 and the 2nd magnet 18 are each magnetized in the rotating shaft direction. As shown in FIGS. 3 and 4, the magnetic poles on the surface facing the second magnet 18 are reversed between the two first magnets 17 adjacent in the circumferential direction (with the magnetic body 25 sandwiched). Yes. Further, even between the two second magnets 18 adjacent in the circumferential direction, the magnetic poles on the surface facing the first magnet 17 are reversed.

  In the present embodiment, as shown in FIG. 2, among the three annular magnet bodies 20 and 21 arranged alternately with respect to the direction of the rotation axis C, the second annular magnet body 21 located in the center is the pulley 2. It is directly attached to the inner surface. As an attachment method, methods such as adhesion, press-fitting, or fixing with screws, bolts, or the like can be employed. On the other hand, the two first annular magnet bodies 20 positioned on the outer side in the rotational axis direction are attached to the outer peripheral surface of the hub 3 (cylindrical member 3b) via two annular support members 22 and 23, respectively. As a method of attaching the two support members 22 and 23 to the hub 3, a method such as adhesion, press-fitting, or fixing with screws, bolts, or the like can be employed. In addition, as a method for attaching the two first annular magnet bodies 20 to the support members 22 and 23, a method such as adhesion, press-fitting, or fixing with screws, bolts, or the like can be employed.

  The supporting members 22 and 23 cover the surfaces of the two first annular magnet bodies 20 (second magnets 17) to be supported on the side opposite to the surface facing the second annular magnet body 21 (first magnet 18). It is provided as follows. That is, the support member 22 on the base end side (left side in FIG. 2) covers the surface on the base end side (left surface in the drawing) of the first annular magnet body 20, and the support member 23 on the tip end side is the first annular magnet. The surface of the body 20 on the tip side (the surface on the right side in the figure) is covered. The two support members 22 and 23 are each made of a magnetic material (ferromagnetic material). Examples of the magnetic material constituting the support members 22 and 23 include soft iron and ferrite (Ni—Zn ferrite, Mn—Zn ferrite, Ba ferrite, or Ferroc planar ferrite). The support members 22 and 23 made of these magnetic materials serve as a yoke, and the leakage of magnetic flux from the surface of the first magnet 17 opposite to the surface facing the second magnet 18 is suppressed.

  Of the two support members 22 and 23, the support member 23 that supports the first annular magnet body 20 (first magnet 17) on the front end side (right side in FIG. 2) is the outer peripheral surface of the first annular magnet body 20. Is also covered. In addition, an annular sliding member 24 is provided on the inner peripheral surface of the pulley 2, and an outer peripheral portion 23 a of the support member 23 covering the first annular magnet body 20 slides with respect to the sliding member 24. It is rotating. That is, the outer peripheral portion 23a of the support member 23 and the sliding member 24 serve as a bearing. The sliding member 24 is preferably made of a material having a small surface friction resistance and excellent wear resistance. For example, molybdenum disulfide, tungsten disulfide, graphite, boron nitride, brass, plating treatment Brass, bronze, and bronze that has been plated can be used. Or synthetic resin materials, such as nylon, polytetrafluoroethylene, and high molecular weight polyethylene, can also be used.

  Next, the operation of the pulley structure 1 of the present embodiment will be described. First, FIG. 5 is a diagram showing a positional relationship between the first magnet 17 and the second magnet 18 when there is no rotational speed difference between the pulley 2 and the hub 3. In FIG. 5, three magnets arranged in the circumferential direction included in each of the annular magnet bodies 20, 21, 20 are shown as viewed from the radial direction of the annular magnet body.

  As shown in FIG. 5, when there is no rotational speed difference (phase difference) between the pulley 2 and the hub 3, the first magnet 17 of the first annular magnet body 20 fixed to the hub 3 and the pulley 2 are fixed. The magnetic force in the direction attracted between the second annular magnet body 21 and the second magnet 18 acts, and the first magnet 17 of the first annular magnet body 20 and the second magnet of the second annular magnet body 21 rotate. They are opposed to each other in the axial direction (left-right direction in FIG. 5).

  In this way, when the pulley 2 and the hub 3 rotate integrally, torque fluctuations generated in the engine are transmitted via the belt 106 and rotational fluctuations occur in the pulley 2. A rotational speed difference (phase difference) occurs between the two. FIG. 6 is a diagram showing the positional relationship between the first magnet 17 and the second magnet 18 when the rotational speed difference is small. FIG. 7 is a diagram showing the positional relationship between the first magnet 17 and the second magnet 18 when the rotational speed difference is large. When a rotational speed difference is generated between the pulley 2 and the hub 3, the circumferential positions (phases) of the first magnet 17 and the second magnet 18 are changed according to the rotational speed difference, as shown in FIGS. Shift.

  As shown in FIG. 6, when the rotational speed difference (phase difference) is small, the magnet 18 a having a small central angle of the second magnet 18 is slightly out of phase with the first magnet 17. However, it does not face the first magnet 17 having the same magnetic pole on the facing surface. Only the magnet 18b having a large central angle among the second magnets 18 partially opposes the first magnet 17 having the same pole on the opposing surface, and the figure between the magnet 18b and the first magnet 17 As shown by an arrow 6 in FIG. Accordingly, torque is generated between the hub 3 to which the first annular magnet body 20 is fixed and the pulley 2 to which the second annular magnet body 21 is fixed so as to reduce the difference in rotational speed between the two. Torque is relatively weak. That is, when the rotational fluctuation is small and the rotational speed difference between the pulley 2 and the hub 3 is small, the torque that acts to eliminate the rotational speed difference does not become too large. Can prevent resonance.

  On the other hand, as shown in FIG. 7, when the rotational speed difference is large, the phase difference between the first magnet 17 and the second magnet 18 becomes large. The magnetic poles on the opposing surface partially face the first magnet 17 having the same polarity. Therefore, as shown by the arrows in FIG. 7, a repulsive magnetic force acts between all the first magnets 17 and the second magnets 18, so that a large torque is generated between the pulley 2 and the hub 3. appear. Therefore, when the rotational fluctuation is large and the rotational speed difference between the pulley 2 and the hub 3 is large, a large torque acts on both, and the large rotational fluctuation can be quickly attenuated.

  According to the pulley structure 1 of the present embodiment, when the rotational speed difference between the pulley 2 and the hub 3 is small, the torque that acts to reduce the rotational speed difference becomes small. Resonance can be prevented from occurring between the hubs 3. Further, when the rotational speed difference between the two is large, the torque also increases, and a large rotational fluctuation can be quickly attenuated.

  Further, in the annular magnet bodies 20 and 21, the magnetic poles on the opposing surfaces of the plurality of first magnets 17 and the plurality of second magnets 18 are the same between the magnets adjacent in the circumferential direction (that is, the magnetization directions are the same). Then, due to the repulsive force acting between these adjacent magnets, it becomes difficult to manufacture the annular magnet bodies 20 and 21 by arranging the plurality of magnets 17 and 18 in the circumferential direction. In the pulley structure 1 of the present embodiment, the magnetic poles on the opposing surfaces are reversed between the magnets adjacent in the circumferential direction, so that the annular magnet bodies 20 and 21 can be easily assembled.

  In the present embodiment, support members 22 and 23 made of a magnetic material are provided on the surface of the first magnet 17 (second annular magnet body 20) opposite to the surface facing the second magnet 18. These support members 22 and 23 serve as a yoke. Accordingly, the leakage of magnetic flux from the first magnet 17 other than the surface facing the second magnet 18 is suppressed as much as possible, and the magnetic energy of the first magnet 17 and the second magnet 18 is reduced to the first magnet 17 and the second magnet 18. Therefore, the torque can be efficiently transmitted between the pulley 2 and the hub 3.

  Further, in the present embodiment, a plurality (six) first magnets 17 and a plurality (six) second magnets 18 are arranged in the circumferential direction, and each has a ring-shaped magnet body (first ring magnet body 20, first ring). A two-ring magnet body 21) is formed. According to this, since the plurality of first magnets 17 and the plurality of second magnets 18 are arranged over the entire circumference, it is possible to apply torque equally between the pulley 2 and the hub 3 in the circumferential direction. it can.

  In addition, as shown in FIG. 2, two first annular magnet bodies 20 (first magnets 17) and one second annular magnet body 21 (second magnet 18) are alternately arranged with respect to the direction of the rotation axis C. Therefore, compared with the case where the first magnet 17 and the second magnet 18 are provided one by one in the rotation axis direction, the magnetic force acting between the pulley 2 and the hub 3 is increased, and between the two Torque can be transmitted reliably.

  Next, modified embodiments in which various modifications are made to the embodiment will be described. However, components having the same configuration as in the above embodiment are given the same reference numerals and description thereof is omitted as appropriate.

  1] The size, shape, number, material, arrangement, etc. of the first magnet 17, the second magnet 18, and the magnetic body 25 depend on the shape of the pulley 2 and the hub 3, the degree of rotation fluctuation that can occur, etc. It can be changed as appropriate.

  For example, the number of the annular magnet bodies 20 and 21 arranged in the direction of the rotation axis of the pulley 2 is limited to three (two first annular magnet bodies 20 and one second annular magnet body 21) as in the above embodiment. It is not a thing. For example, like the pulley structure 1A shown in FIG. 8, the number of the 1st annular magnet bodies 20 and the 2nd annular magnet bodies 21 arrange | positioned regarding the direction of the rotating shaft C may each be one. In the embodiment of FIG. 8, the support members 22A and 23 serving as yokes are respectively provided on the outer surfaces of the first annular magnet body 20 and the second annular magnet body 21 (surfaces opposite to the opposing surfaces). Is provided. Alternatively, four or more first annular magnet bodies 20, 21 may be provided so as to be alternately arranged in the rotation axis direction.

  Further, the number of magnets 17 and 18 and magnetic bodies 25 constituting one annular magnet body 20 and 21 need not be six, and can be changed as appropriate. Further, the central angle of the magnets 17 and 18 formed in a substantially fan shape or the magnetic body 25 can be changed as appropriate. Furthermore, the magnets 17 and 18 and the magnetic bodies 25 and 26 need not be arranged over the entire circumference in the circumferential direction to form an annular magnet body, and the magnets 17 and 18 and the magnetic body 25 are arranged only in a part of the circumferential direction. It may be a configuration.

  Moreover, in the said embodiment, although the 1st magnet 17 and the magnetic body 25 were provided in the hub 3 side, and the 2nd magnet 18 was provided in the pulley 2 side, the reverse may be sufficient. That is, a plurality of first magnets 17 having the same central angle are provided along the circumferential direction on the pulley 2 side, and the second magnet 18 (two types of magnets 18a and 18b) are provided on the hub 3 side. ) May be provided along the circumferential direction.

  2] In the above embodiment, the first magnet 17 (first annular magnet body 20) and the second magnet 18 (second annular magnet body 21) face each other in the rotation axis direction. The magnet 18 may face the radial direction of the pulley 2. For example, in the pulley structure 1B shown in FIG. 9, the first annular magnet body 20B is fixed to the pulley 2B via an annular support member 22B made of a magnetic material, while the hub 3B has a second structure. An annular magnet body 21B is fixed via an annular support member 23B made of a magnetic material. In addition, the first annular magnet body 20B on the pulley 2B side is formed to have a diameter larger than the diameter of the second annular magnet body 21B on the hub 3B side, and then radially inward of the first annular magnet body 20B. The second annular magnet body 21B is disposed with a gap therebetween.

  As shown in FIG. 10, the first annular magnet body 20B located on the outer side is composed of six first magnets 17B and six magnetic bodies 25B arranged alternately in the circumferential direction. The six first magnets 17B are magnetized in the radial direction, and the magnetic poles on the inner peripheral surface (the surface facing the second magnet 18B) are reversed between the two first magnets 17B adjacent in the circumferential direction. Yes. The second annular magnet body 21B located on the inner side is composed of six second magnets 18B arranged alternately in the circumferential direction, and the six second magnets 18B have two different central angles. It consists of magnets 18Ba and 18Bb. The six second magnets 18B are also magnetized in the radial direction, and the magnetic poles on the outer peripheral surface (the surface facing the first magnet 17B) are reversed between the two second magnets 18B adjacent in the circumferential direction. .

  The operation of the pulley structure 1B when a rotational speed difference is generated between the pulley 2B and the hub 3B is basically the same as that of the pulley structure 1 of the above embodiment. That is, when a rotational speed difference occurs between the pulley 2B and the hub 3B, the circumferential positions of the first magnet 17B of the first annular magnet body 20B and the second magnet 18B of the second annular magnet body 21B are shifted. When the rotational speed difference (phase difference) is small, only the second magnet 18Bb having a large central angle is partially opposed to the first magnet 17B having the same magnetic pole on the opposing surface, so that the rotational speed difference is eliminated. Excessive torque will not be generated.

  5] In the above embodiment, the support members 22 and 23 for attaching the first magnet 17 to the hub 3 are made of a magnetic material, but the present invention is not limited to such a form. For example, even if the first magnet 17 or the second magnet 18 is directly fixed to the corresponding pulley 2 or the hub 3 and a magnetic material serving as a yoke is attached to the first magnet 17 or the second magnet 18. Good. Furthermore, such a magnetic material serving as a yoke may be omitted.

  As described above, an example in which the present invention is applied to a pulley structure of an engine accessory drive system has been described as an embodiment of the present invention. However, the application target of the present invention is not limited to this. For example, in the fields of building materials, furniture, machinery, etc., it is used for various applications such as pulley structures used to change torque according to the opening / closing angle of opening / closing members such as windows, doors, lids, etc. The present invention can also be applied to a pulley structure.

  Next, specific examples of the present invention will be described together with comparative examples.

Example 1
As the first magnet 17 provided in the hub 3, a neodymium magnet having a fan shape with an outer diameter of 58 mm, an inner diameter of 28 mm, a thickness of 6 mm, and a central angle (α) of 50 degrees and magnetized in the direction of the rotation axis was used. The magnetic body 25 alternately combined with the first magnets 17 was made of S25C material formed in a sector shape having an outer diameter of 58 mm, an inner diameter of 28 mm, a thickness of 6 mm, and a central angle (β) of 10 degrees. The first magnets 17 are alternately arranged in the circumferential direction so that the magnetic poles are reversed, and the magnetic body 25 is arranged between the first magnets 17 adjacent in the circumferential direction, so that the six first magnets 17 Two first annular magnet bodies 20 composed of six magnetic bodies 25 were produced.

  The two types of magnets 18a and 18b of the second magnet 18 provided on the pulley 2 are fan-shaped neodymium magnets having an outer diameter of 56 mm, an inner diameter of 24 mm, a thickness of 6 mm, and a central angle (α) of 50 degrees and magnetized in the direction of the rotation axis. Then, a neodymium magnet magnetized in the direction of the rotation axis with a fan shape having an outer diameter of 56 mm, an inner diameter of 24 mm, a thickness of 6 mm, and a central angle (α + 2β) of 70 degrees was used. The two types of second magnets 18 were alternately arranged in the circumferential direction so that the magnetic poles were reversed, and one second annular magnet body 21 composed of six second magnets 18 was produced.

  Two first annular magnet bodies 20 and one second annular magnet body 21 are arranged at intervals of 0.5 mm, and the outer surfaces of the two first annular magnet bodies 20 have an outer diameter of 56 mm, an inner diameter of 28 mm, and a thickness of 5 mm. The S25C material was laminated as a back yoke. These three annular magnet bodies 20, 21, 20 were attached to the hub 3 and the pulley 2 shown in FIG. 1 to produce a pulley structure.

(Example 2)
The specifications were the same as in Example 1 except that the central angle (α) of the first magnet 17 and the second magnet 18a was 45 degrees and the central angle (β) of the magnetic body 25 was 15 degrees.

(Example 3)
The specifications were the same as in Example 1 except that the central angle (α) of the first magnet 17 and the second magnet 18a was 42.5 degrees and the central angle (β) of the magnetic body 25 was 17.5 degrees.

Example 4
The specifications were the same as in Example 1 except that the central angle (α) of the first magnet 17 and the second magnet 18a was 40 degrees and the central angle (β) of the magnetic body 25 was 20 degrees.

(Comparative Example 1)
The central angle (α) of the first magnet 17 and the second magnet 18a is set to 60 degrees, and the central angle (β) of the magnetic body 25 is set to 0 degrees (that is, the six first magnets 17 without the magnetic body 25 being disposed). The configuration was the same as that of Example 1 except that the annular magnet body was configured only with this.

  For each of the pulley structures of Examples 1 to 4 and Comparative Example 1 described above, the relationship between the phase difference between the pulley and the hub and the torque was determined. Specifically, the rotating shaft attached to the hub is inserted into the rotating shaft of a torque meter (Ishido Electric Manufacturing Co., Ltd .: Torque measuring machine) to enable the hub to rotate integrally with the torque meter, while the surface of the pulley Was fixed mechanically in a non-rotatable manner. In this state, the relationship between the rotation angle and torque when the torque meter was rotated counterclockwise (forward rotation) at 1.5 rpm was determined. The result is shown in FIG.

  From FIG. 11, in Comparative Example 1, the torque change rate is large in the range where the phase difference (rotation angle) between the pulley and the hub is small, whereas in Examples 1 to 4, the torque in the range where the phase difference is small. It can be seen that the rate of change is small.

  Further, in Example 1 in which β = 10 degrees, the maximum torque value is almost the same as that in Comparative Example 1, but the torque change rate in the range where the phase difference is small (in the range where the rotation angle is small in the graph of FIG. 11). The slope of () is reduced to about ３ of Comparative Example 1. Further, in Example 2 (β = 15 degrees) and Example 3 (β = 17.5 degrees), the maximum torque value is reduced by about 10% compared to Comparative Example 1, and in Example (β = 20 degrees). Although the maximum torque value is reduced by about 20%, the torque change rate in the range where the phase difference is small is ¼ or less of that of Comparative Example 1, respectively.

  Moreover, the Examples 1-4 and the comparative example 1 produced the pulley structure which changed the shape of the 1st magnet and the 2nd magnet (Examples 5-8 and the comparative example 2). The first magnet 17 had an outer diameter of 52 mm, an inner diameter of 26 mm, and a thickness of 6 mm, and the second magnet 18 had an outer diameter of 48 mm, an inner diameter of 24 mm, and a thickness of 6 mm.

  Regarding the central angles of the magnets and magnetic bodies, Example 5 has α = 52.5 degrees and β = 7.5 degrees, Example 6 has α = 50 degrees, β = 10 degrees, and Example 7 has α = 45 degrees. , Β = 15 degrees, Example 8 has α = 40 degrees and β = 20 degrees, and Comparative Example 2 has α = 60 degrees and β = 0 degrees. Other specifications are the same as those in Examples 1 to 4 and Comparative Example 1. FIG. 12 shows the results of obtaining the relationship between the phase difference between the pulley and the hub and the torque for each of the pulley structures of Examples 5 to 8 and Comparative Example 2.

  As can be seen from FIG. 12, in Example 5 (β = 7.5 degrees), the maximum torque value is almost the same as that in Comparative Example 2, while the torque change rate in the range where the phase difference is small is 1 of Comparative Example 2. / 3 or smaller. In Example 7 (β = 15 degrees), the maximum torque value is reduced by about 10% compared to Comparative Example 2, and in Example 8 (β = 20 degrees), the maximum torque value is reduced by about 15%. However, the torque change rate in the range where the phase difference is small is 1/4 or less that of Comparative Example 1.

  Since the maximum torque value greatly depends on the outer diameter of the magnet, the optimum value of β varies depending on how much torque is required. From Examples 1-4 and Examples 5-8 above, In order to allow the torque value to be reduced to about 10% when the magnetic material is not used (Comparative Examples 1 and 2), and to make the torque change rate in the range where the phase difference is small, β is It can be said that the range of 7.5 to 20 degrees is desirable.

1, 1A, 1B Pulley structure 2, 2A, 2B Pulley 3, 3A, 3B Hub 17, 17B First magnet 18, 18B Second magnet 22, 22A, 22B Support member 23, 23B Support member 25, 25B Magnetic body

Claims (3)

A first rotating body;
A second rotating body rotatable relative to the first rotating body;
A plurality of first magnets provided on one of the first rotating body and the second rotating body and disposed along a circumferential direction;
A plurality of second magnets arranged along the circumferential direction, provided on the other of the first rotating body and the second rotating body so as to face the first magnet;
The plurality of first magnets have the same center angle, and the plurality of first magnets are arranged with a magnetic body interposed therebetween in the circumferential direction,
The plurality of second magnets are composed of two types of magnets, a magnet having the same central angle as the first magnet and a magnet having a larger central angle than the first magnet. Alternately arranged in the direction,
Furthermore, the magnetic poles on the surface facing the second magnet are opposite between the two first magnets adjacent in the circumferential direction, and the first magnet is also between the two second magnets adjacent in the circumferential direction. A pulley structure characterized in that the magnetic poles on the surface facing one magnet are reversed.   2. The yoke according to claim 1, wherein at least one of the plurality of first magnets and the plurality of second magnets is provided with a yoke made of a magnetic material on a surface opposite to the facing surface. Pulley structure. The pulley structure according to claim 1 or 2, wherein each of the plurality of first magnets and the plurality of second magnets constitutes an annular magnet body.

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