JP5175232B2 - Pulley structure - Google Patents

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 is provided on a pulley (first rotating body) around which a belt is wound, and on the inner side of the pulley so as to be relatively rotatable with respect to the pulley. A hub (second rotating body) coupled to the shaft and a rubber elastic body (rubber coupling) coupling the pulley and the hub are included. 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.

  Moreover, the pulley structure described in Patent Literature 2 includes a damper main body (first rotating body) assembled to the crankshaft and a damper mass (second rotating body) provided inside the damper main body. A plurality of permanent magnets arranged in the circumferential direction are fixed to the damper mass, while a copper plate facing the plurality of permanent magnets of the damper mass is fixed to the damper main body. When a rotational speed difference is generated between the damper main body and the damper mass due to the torsional vibration generated in the crankshaft, an eddy current is generated in the copper plate due to the speed difference between the permanent magnet and the copper plate. At this time, a force that reduces the speed difference between the two rotating bodies (damper main body and damper mass) acts between the two rotating bodies (damper main body and damper mass) due to the eddy current generated in the copper plate, and the rotational fluctuation of the damper main body is suppressed.

Japanese Utility Model Publication No. 63-68540 JP 2002-286094 A

  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, as in the pulley structure of Patent Document 2, an eddy current generated in the copper plate due to the speed difference between the permanent magnet and the copper plate suppresses the two rotors to reduce the speed difference between them. In the configuration in which the above is applied, since it is not necessary to use a rubber elastic body, the above-described problem does not occur. However, the restraining force that can be applied to the two rotating bodies by the eddy current is quite small, and when the rotational fluctuation generated in one rotating body is large, it is difficult to quickly attenuate the rotational fluctuation. is there.

  An object of the present invention is to provide a pulley structure that can quickly attenuate a rotational fluctuation generated in a rotating body without using a rubber elastic body.

Means for Solving the Problems and Effects of the Invention

A first rotating body, a second rotating body that can rotate relative to the first rotating body, a first magnet provided on the first rotating body, and the second rotating body in the direction of the rotation axis A second magnet that is provided so as to sandwich the first magnet and that can be opposed to the first magnet in the rotation axis direction, and at least one of the first magnet and the second magnet is A plurality of magnets which are magnetized in the circumferential direction and are arranged in the circumferential direction with the magnetic material interposed therebetween, and the magnetic poles of the two magnets sandwiching the magnetic material in the circumferential direction have the same polarity. is there.

  According to the present invention, at least one of the first magnet provided on the first rotating body and the second magnet provided on the second rotating body is arranged in the circumferential direction across the magnetic body. The magnetic poles of the two magnets sandwiching the magnetic body in the circumferential direction have the same polarity. The magnetic flux emitted in the circumferential direction from the one magnet passes through the magnet adjacent to the magnet in the circumferential direction and flows to the other magnet facing the one magnet, thereby opposing the first magnet. And the second magnet attract each other. Further, when a rotational speed difference (phase difference) occurs between the first rotating body and the second rotating body, the phases of the first magnet and the second magnet are shifted. Since the magnetic flux passing between the second magnets is inclined with respect to the direction in which the two magnets face each other, a magnetic force acts so as to attract the circumferential direction between the first magnet and the second magnet that are out of phase. That is, torque acts between the first rotating body and the second rotating body so as to eliminate the rotational speed difference, so that the rotational fluctuation generated in one rotating body is attenuated.

  Here, the magnetic force between the first magnet and the second magnet acting on the first rotating body and the second rotating body so as to reduce the rotational speed difference is a restraining force acting on the rotating body by the conventional eddy current. Compared to, it is much more powerful. Therefore, even when a large rotational fluctuation occurs in one of the rotating bodies, the rotational fluctuation can be quickly attenuated. Further, since the rubber elastic body is not used to attenuate the rotational fluctuation, problems such as aging deterioration of the rubber elastic body, fatigue failure, or sound generation at the time of elastic deformation of the rubber elastic body do not occur.

  Furthermore, in the present invention, 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 first magnet and the second magnet are slightly shifted from each other. However, since the surface of the one magnet that is not connected to the magnetic body is not a magnetic pole, the increase in potential due to this surface facing the other magnet is small. Accordingly, when the rotational speed difference between the two rotating bodies is small, the torque that acts to eliminate the rotational speed difference does not become too large, and resonance occurs between the first rotating body and the second rotating body. Can be prevented.

  A pulley structure according to a second aspect of the present invention is the pulley structure according to the first aspect, wherein the first rotating body is provided with a plurality of the first magnets, and the plurality of first magnets and the magnetic body are alternately arranged in a circumferential direction. The second rotating body is also provided with a plurality of second magnets, and the plurality of second magnets and the magnetic body are alternately arranged in a circumferential direction. Is.

According to this configuration, since the plurality of first magnets and the plurality of second magnets are arranged in the circumferential direction, torque is evenly distributed in the circumferential direction between the first rotating body and the second rotating body. Can act.
A pulley structure according to a third invention is characterized in that, in the second invention, the central angle of the magnetic body is 0.8 times or more of the central angle of the one magnet.

The pulley structure according to a fourth aspect of the present invention is the pulley structure according to the first aspect, wherein a plurality of the other ones of the first magnet and the second magnet are arranged in the circumferential direction without sandwiching the magnetic body. Are arranged so that the magnetic poles on the surface facing the one magnet are opposite between the magnets adjacent in the circumferential direction.

  As described above, when the difference between the rotational speeds of the two rotating bodies is small by arranging a plurality of the other magnets of the first magnet and the second magnet in the circumferential direction without sandwiching the magnetic body, the rotational speed difference is reduced. As the phase difference increases, the gradient of the magnetic flux efficiently increases with respect to the rotating shaft, preventing the torque from acting excessively. It becomes possible to attenuate quickly.

The pulley structure according to a fifth aspect of the present invention is the pulley structure according to any one of the first to fourth aspects, wherein the one magnet and the magnetic body are alternately arranged in the circumferential direction to constitute an annular magnet body. It is characterized by this.

  According to this configuration, since the plurality of magnets arranged alternately with the magnetic body are distributed over the entire circumference, torque is evenly distributed in the circumferential direction between the first rotating body and the second rotating body. Can act.

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. It is the IV-IV sectional view taken on the line of FIG. It is the figure which showed typically the flow of the magnetic flux between two annular magnet bodies when there is no rotational speed difference between a pulley and a hub. FIG. 5 is a cross-sectional view corresponding to FIG. 4 of the pulley structure when there is a difference in rotational speed between the pulley and the hub. It is the figure which showed typically the flow of the magnetic flux between two annular magnet bodies when there exists a 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 a perspective view of the annular magnet body concerning another modification. It is the figure which showed typically the flow of the magnetic flux between the three annular magnet bodies of FIG. 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 cyclic | annular magnet body of the pulley structure of FIG. 11 from the rotating shaft direction. It is a perspective view of the annular magnet body of the comparative example 1 comprised only with the magnet. It is a graph which shows the relationship between the rotation angle of the pulley structure of Examples 1-5 and Comparative Example 1, and 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 is connected to a cylindrical pulley 2 (first rotating body) around which the transmission belt 106 is wound, and a driven shaft (auxiliary shaft) 103 and to the inside of the pulley 2. And a hub 3 (second rotating body) provided on the head. 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 nonmagnetic materials include aluminum alloys, titanium alloys, and synthetic resins.

  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 3 b located on the distal end side and the pulley 2, and the first annular magnet body 20 fixed to the pulley 2 is formed in the magnet housing chamber 16. And two second annular magnet bodies 21 fixed to the cylindrical member 3b of the hub 3 are accommodated.

  3 is a perspective view of the annular magnet bodies 20 and 21 shown in FIG. 2, and FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. The first annular magnet body 20 is fixed to the pulley 2 on the outer peripheral surface thereof. As shown in FIGS. 3 and 4, the first annular magnet body 20 is composed of four first magnets 17 and a magnetic body 25 made of four magnetic materials (preferably soft magnetic materials). Both the first magnet 17 and the magnetic body 25 have a substantially sector shape with a central angle (45 degrees), and the four first magnets 17 and the four magnetic bodies 25 are alternately arranged in the circumferential direction. A first annular magnet body 20 is configured.

  The second annular magnet body 21 is fixed to the hub 3 on the inner peripheral surface thereof. The second annular magnet body 21 is also composed of a magnetic body 26 made of four second magnets 18 and four magnetic materials (preferably soft magnetic materials), like the first annular magnet body 20. . Both the second magnet 18 and the magnetic body 26 have a substantially sector shape with a central angle (45 degrees), and the four second magnets 18 and the four magnetic bodies 26 are alternately arranged in the circumferential direction. The second annular magnet body 21 is configured.

  In addition, one first annular magnet body 20 fixed to the pulley 2 and two second annular magnet bodies 21 fixed to the hub 3 are alternately arranged with a gap in the direction of the rotation axis C of the pulley 2. ing. In other words, the first annular magnet body 20 including the first magnet 17 is sandwiched between the second annular magnet bodies 21 including the second magnet 18 in the rotation axis direction.

  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 and the magnetic body 26, 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.

  Further, the first magnet 17 and the second magnet 18 are respectively magnetized in the circumferential direction. As shown in FIG. 3, in the first annular magnet body 20, the magnetic poles on the magnetic body 25 side of the two first magnets 17 sandwiching one magnetic body 25 in the circumferential direction have the same polarity. Similarly, in the second annular magnet body 21, the magnetic poles on the magnetic body 26 side of the two second magnets 18 sandwiching one magnetic body 26 in the circumferential direction have the same polarity.

  In the present embodiment, among the three annular magnet bodies 20, 21 arranged alternately with respect to the direction of the rotation axis C, the first annular magnet body 20 located at the center is attached to the inner peripheral surface of the pulley 2. However, as the attachment method, a method such as adhesion, press-fitting, or fixing with a screw or a bolt can be employed. Further, the two second annular magnet bodies 21 positioned outside in the rotation axis direction are attached to the outer peripheral surface of the hub 3 (cylindrical member 3b), but to the hub 3 of these two second annular magnet bodies 21. As the mounting method, methods such as adhesion, press-fitting, or fixing with screws or bolts can be adopted.

  Next, the operation of the pulley structure 1 of the present embodiment will be described. As shown in FIG. 4, in a state where there is no rotational speed difference (phase difference) between the pulley 2 and the hub 3, the four first magnets 17 of the first annular magnet body 20 fixed to the pulley 2 and the hub 3. The four second magnets 18 of the second annular magnet body 21 fixed to each other are opposed to each other with respect to the rotation axis direction (perpendicular to the plane of FIG. 4).

  FIG. 5 is a diagram schematically showing the flow of magnetic flux between the two second annular magnet bodies 20 and 21 when there is no rotational speed difference between the pulley 2 and the hub 3. In FIG. 5, the magnets 17 (18) and the magnetic bodies 25 (26) alternately arranged in the circumferential direction of the annular magnet bodies 20, 21 are viewed from the outside in the radial direction of the annular magnet bodies ( (Development).

  In a state where there is no rotational speed difference (phase difference) between the pulley 2 and the hub 3 and both are rotating together, the first magnet 17 of the first annular magnet body 20 is shown in FIGS. 4 and 5. And the circumferential position of the second magnet 18 of the second annular magnet body 21 coincide with each other, and both the magnets 17 and 18 face each other in the rotation axis direction. Since the magnetization directions of the first magnet 17 and the second magnet 18 are both in the circumferential direction, the magnetic flux B is generated in the circumferential direction from the N pole of each magnet 17 (18).

  The magnetic flux B emitted from the N pole of the first magnet 17 in the circumferential direction flows to the magnetic body 25 adjacent to the first magnet 17 in the circumferential direction. Further, the magnetic flux B flows through the gap between the two annular magnet bodies 20 and 21 to the opposing magnetic body 26 and reaches the S pole of the second magnet 18. The flow of the magnetic flux B from the N pole of the second magnet 18 to the S pole of the first magnet 17 is the same as above. As described above, in the state where there is no difference in rotational speed between the pulley 2 and the hub 3, the direction of the magnetic flux B flowing between the magnetic body 25 and the magnetic body 26 rotates in the gap between the two annular magnet bodies 20 and 21. It is parallel to the axial direction (left-right direction in FIG. 5). Therefore, no torque is generated between the pulley 2 provided with the first annular magnet body 20 and the hub 3 provided with the second annular magnet body 21.

  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. 7 is a diagram schematically showing the flow of magnetic flux between the two annular magnet bodies 20 and 21 in a state where a rotational speed difference is generated between the pulley 2 and the hub 3. As shown in FIG. 7, the direction of the magnetic flux B between the first annular magnet body 20 and the second annular magnet body 21 by shifting the circumferential positions (phases) of the first magnet 17 and the second magnet 18. However, the magnetic force attracting in the circumferential direction acts between the first magnet 17 and the second magnet 18 with respect to the rotation axis direction (left-right direction in FIG. 7). That is, torque acts between the pulley 2 to which the first annular magnet body 20 is fixed and the hub 3 to which the second annular magnet body 21 is fixed so as to eliminate the rotational speed difference between the two. Therefore, the rotational fluctuation is attenuated.

  Here, the magnetic force between the first magnet 17 and the second magnet 18 acting on the pulley 2 and the hub 3 so as to reduce the rotational speed difference between them acts on the rotating body by the conventional eddy current. Compared to restraint, it is much more powerful. Therefore, even when a large rotational fluctuation occurs in the pulley 2, it is possible to quickly attenuate the rotational fluctuation. Further, since the rubber elastic body is not used to attenuate the rotational fluctuation, problems such as aging deterioration of the rubber elastic body, fatigue failure, or sound generation at the time of elastic deformation of the rubber elastic body do not occur.

  Furthermore, the annular magnet bodies 20 and 21 have a configuration in which magnets 17 (18) and magnetic bodies 25 (26) magnetized in the circumferential direction are alternately arranged in the circumferential direction, and one magnetic body 25 (26 Is sandwiched between the same-polar surfaces of the two magnets 17 (18). Therefore, as shown in FIG. 7, when a relatively small rotational speed difference (phase difference) is generated between the pulley 2 and the hub 3, when viewed from the first magnet 17, the second magnet that has been opposed earlier. 18 is partially opposed to the magnetic body 26 adjacent in the circumferential direction.

  At this time, as described above, the magnetic flux emitted from the N pole of one magnet 17 (18) between the two annular magnet bodies 20 and 21 facing each other passes through the magnetic bodies 25 and 26 and the other magnet. 18 (17) S pole. Therefore, even if a phase difference occurs between the first magnet 17 and the second magnet 18, the gap between the magnetic body 25 and the first annular magnet body 20 (magnetic body 25) and the second annular magnet body 21 (magnetic body 26). The inclination of the magnetic flux flowing between the magnetic bodies 26 with respect to the rotation axis direction can be kept small. This is because the magnetic flux does not reach the central portion of the magnetic body 26 from the central portion of the magnetic body 25 but passes through a route having a small magnetic resistance. In other words, when a phase difference occurs between the first magnet 17 and the second magnet 18, the magnetic potential becomes high, but the magnetic body 25 ( Since the surface not connected to (26) (the end surface in the direction of the rotation axis C) is not a magnetic pole, the increase in potential due to this surface facing the other magnet 18 (17) is small. Therefore, when the rotational speed difference between the pulley 2 and the hub 3 is small and the magnets 17 and 18 have a small phase difference so as to partially face the magnetic bodies 26 and 25, the rotational speed difference between the pulley 2 and the hub 3 is eliminated. Thus, it is possible to prevent the resonance between the pulley 2 and the hub 3 from occurring.

  Moreover, in this embodiment, both the 1st magnet 17 provided in the pulley 2 and the 2nd magnet 18 provided in the hub 3 are alternately arrange | positioned regarding the magnetic bodies 25 and 26 and the circumferential direction, respectively, and are cyclic | annular. The magnet bodies 20 and 21 are configured. According to this configuration, since the plurality of first magnets and the plurality of second magnets are arranged in the circumferential direction, torque is applied equally between the pulley 2 and the hub 3 in the circumferential direction. Can do.

  In the present embodiment, the four first magnets 17 and the four second magnets 18 are each composed of a permanent magnet. Therefore, the pulley 2 and the hub 3 are connected by a magnetic flux generated semipermanently from the permanent magnet, and the rotational fluctuation is smaller than that of a rubber elastic body that deteriorates over time or fatigue due to long-term use. It is difficult to cause a problem that the function of attenuating is deteriorated or incapable of being attenuated.

  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 and the second magnet 18 and the magnetic bodies provided on them depend on the shape of the pulley and hub, the degree of rotation fluctuation that can occur, etc. These 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 (one first annular magnet body 20 and two second annular magnet bodies 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. 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 constituting one annular magnet body 20 and 21 is not necessarily four, and can be changed as appropriate. In other words, the central angle of the magnets 17 and 18 formed in a substantially fan shape need not be 45 degrees, and may be changed to another angle.

  Furthermore, there is no particular need to make the center angle of the magnets 17 and 18 equal to the center angle of the magnetic bodies 25 and 26, and the center angles of both may be different. In particular, the larger the central angle of the magnetic bodies 25, 26, the smaller the phase difference between the first magnet 17 and the second magnet 18 than the central angle of the magnetic bodies 25, 26 occurs. The opposing area of the magnetic body 25 sandwiched between the magnetic body 26 and the magnetic body 26 sandwiched between the second magnets 18 is kept wide. Therefore, the inclination of the magnetic flux flowing between the two annular magnet bodies 20 and 21 (between the magnetic body 25 and the magnetic body 26) with respect to the direction in which the annular magnet bodies 20 and 21 face (rotational axis direction) is further reduced. Since it is almost parallel to the rotation axis direction, the torque acting between the pulley 2 and the hub 3 is reduced.

  Furthermore, it is not necessary that the magnet 17 (18) and the magnetic body 25 (26) are arranged over the entire circumference in the circumferential direction to form an annular magnet body, and the magnet 17 (18) and the magnetic body are only partly in the circumferential direction. 25 (26) may be arranged.

  Further, it is not always necessary that the magnetic body is disposed in the circumferential direction with respect to both the first magnet 17 and the second magnet 18, and only one of the first magnet 17 and the second magnet 18 is provided with the magnetic body. Also good. For example, as shown in FIG. 9, the first annular magnet body 20 fixed to the pulley 2 is composed of six first magnets 17 and six magnetic bodies 25 arranged alternately in the circumferential direction, The second annular magnet body 121 fixed to the hub 3 may be composed of only a plurality of (for example, six) second magnets 18 arranged in the circumferential direction without sandwiching the magnetic body. The plurality of second magnets are arranged such that the magnetic poles on the surfaces facing the first magnets (the left and right side surfaces in FIG. 9) are opposite between the magnets adjacent in the circumferential direction. As shown in FIG. 10, the magnetic flux emitted from the N pole of the first magnet 17 reaches the S pole of the second magnet 18 through the magnetic body 25 adjacent to the N pole in the circumferential direction. The magnetic flux emitted from the N pole of the second magnet 18 reaches the S pole of the first magnet 17 through the magnetic body 25.

  As described above, one of the first magnet 17 and the second magnet 18 is arranged in the circumferential direction so as to sandwich the magnetic body, while a plurality of other magnets are arranged in the circumferential direction without sandwiching the magnetic body. When the difference in rotational speed between the pulley 2 and the hub 3 is small, the torque acting to eliminate this rotational speed difference is prevented from being excessive, and when the rotational speed difference is large, the pulley 2 It is possible to quickly attenuate the rotational fluctuation by applying a large torque between the hub 3 and the hub 3.

  2] In the above embodiment, the first magnet 17 on the pulley side and the second magnet 18 on the hub side face each other in the rotational axis direction, but the first magnet 17 and the second magnet 18 face each other in the radial direction of the pulley. May be. For example, in the pulley structure 1B shown in FIG. 11, the first annular magnet body 20B is fixed to the pulley 2B, while the second annular magnet body 21B is fixed to the hub 3B. 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.

  FIG. 12 is a view of the annular magnet bodies 20B and 21B of FIG. 11 viewed from the direction of the rotation axis. As shown in FIG. 12, the first annular magnet body 20B located on the radially outer side is composed of four first magnets 17B and four magnetic bodies 25B that are alternately arranged in the circumferential direction. The four first magnets 17B are respectively magnetized in the circumferential direction, and the two first magnets 17B sandwiching one magnetic body 25B in the circumferential direction have the same magnetic poles on the magnetic body 25B side. The second annular magnet body 21B located on the inner side is composed of four second magnets 18B and four magnetic bodies 26B that are alternately arranged in the circumferential direction. The four second magnets 18B are also magnetized in the circumferential direction, and the two second magnets 18B sandwiching the magnetic body 26B in the circumferential direction have the same magnetic poles on the magnetic body 26B side.

  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 is generated between the pulley 2B and the hub 3B, the rotational speed difference is generated between the pulley 2B and the hub 3B by the magnetic force in the attracting direction acting between the two types of magnets 17B and 18B. Torque is generated in the direction to cancel. Further, when a relatively small rotational speed difference is generated between the pulley 2B and the hub 3B, and the first magnet 17B and the second magnet 18B are out of phase, the first annular magnet body 20B and the second annular magnet body 21B. Since the magnetic force acting in the circumferential direction between the two is relatively small, no excessive torque is generated in the direction of eliminating the rotational speed difference.

  3] If the rotational fluctuation generated in the pulley 2 is very large, the rotational fluctuation may not be attenuated immediately by the magnetic force between the first magnet 17 and the second magnet 18 alone. Therefore, a stopper structure that suppresses further increase of the phase difference when the phase difference between the pulley 2 and the hub 3 reaches a certain angle may be provided. For example, protrusions are provided on the inner peripheral surface of the pulley 2 and the inner peripheral surface of the hub 3, respectively, and when the phase difference between the pulley 2 and the hub 3 becomes a constant angle, the protrusions of the two abut in the circumferential direction. By engaging (engaging), the pulley 2 and the hub 3 may be integrally rotated to prevent relative rotation in the direction in which the phase difference increases.

  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 on the pulley 2, a neodymium magnet (residual magnetic flux density of 1.15 T) having an outer diameter of 58 mm, an inner diameter of 26 mm, a thickness of 6 mm, and a sector shape with a central angle of 20 degrees was used. The magnetic body 25 combined with the first magnet 17 was made of S25C material having the same outer diameter, inner diameter, and thickness as the first magnet 17 and formed in a sector shape with a central angle of 25 degrees. Then, one first annular magnet body 20 in which eight first magnets 17 and eight magnetic bodies 25 are alternately arranged in the circumferential direction was produced.

  As the second magnet 18 provided in the hub 3, a neodymium magnet (residual magnetic flux density of 1.15T) having an outer diameter of 56 mm, an inner diameter of 24 mm, a thickness of 6 mm, and a sector shape with a central angle of 20 degrees was used. The magnetic body 26 combined with the second magnet 18 was made of S25C material having the same outer diameter, inner diameter, and thickness as the second magnet 18 and having a sector shape with a central angle of 25 degrees. Then, two second annular magnet bodies 21 in which eight second magnets 18 and eight magnetic bodies 26 are alternately arranged in the circumferential direction were produced.

  With the above-described one first annular magnet body 20 sandwiched between two second annular magnet bodies 21, these three annular magnet bodies 21, 20, 21 are attached to the pulley 2 and the hub 3 shown in FIG. A pulley structure was produced. In addition, the arrangement | positioning space | interval of the three annular magnet bodies 21, 20, and 21 was 0.5 mm.

(Example 2)
The specifications were the same as in Example 1 except that the central angle of the first magnet 17 and the second magnet 18 was 25 degrees and the central angle of the magnetic bodies 25 and 26 was 20 degrees.

(Example 3)
The specifications were the same as in Example 1 except that the central angle of the first magnet 17 and the second magnet 18 was 30 degrees, and the central angle of the magnetic bodies 25 and 26 was 15 degrees.

Example 4
The specifications were the same as in Example 1 except that the central angle of the first magnet 17 and the second magnet 18 was 35 degrees and the central angle of the magnetic bodies 25 and 26 was 10 degrees.

(Example 5)
As the first magnet 17 provided on the pulley 2, a neodymium magnet (residual magnetic flux density of 1.15 T) having a fan shape with an outer diameter of 58 mm, an inner diameter of 26 mm, a thickness of 6 mm and a central angle of 50 degrees was used. The magnetic body 25 combined with the first magnet 17 was made of S25C material having the same outer diameter, inner diameter, and thickness as the first magnet 17 and formed in a sector shape with a central angle of 10 degrees. Then, one first annular magnet body 20 in which six first magnets 17 and six magnetic bodies 25 are alternately arranged in the circumferential direction was created.
Further, as shown in FIG. 9 described above, the two annular magnet bodies 121 fixed to the hub 3 are configured by only a plurality (six) second magnets 18 arranged in the circumferential direction without sandwiching the magnetic bodies. . Each of the second magnets 18 has an outer diameter of 56 mm, an inner diameter of 24 mm, a thickness of 6 mm, and a sector shape with a central angle of 60 degrees. Further, the second magnet 18 is magnetized in the direction of the rotation axis C, and the magnetic poles on the surfaces facing the first annular magnet body 20 (left and right side surfaces in FIG. 9) are opposite between adjacent magnets. Has been placed. Further, on the surface of the second annular magnet body 121 composed of the second magnet 18 that does not face the first annular magnet body 20 (left and right outer surfaces in FIG. 9), an outer diameter of 56 mm and an inner diameter of 24 mm are provided. An S25C material having a thickness of 5 mm was attached.

(Comparative Example 1)
As shown in FIG. 13, each of the three annular magnet bodies 121, 120, 121 is composed of eight magnets 17 (18) magnetized in the direction of the rotation axis C. The eight magnets 17 (18) arranged in the circumferential direction are arranged so that the magnetic poles on the surfaces facing the other annular magnet bodies (left and right side surfaces in FIG. 13) are opposite between adjacent magnets. The central angle of each magnet 17 (18) is 45 degrees. The other specifications were the same as in Example 1. A S25C material having an outer diameter of 56 mm, an inner diameter of 24 mm, and a thickness of 5 mm was attached as a back yoke to the surfaces of the two left and right annular magnet bodies 121 not facing the annular magnet body 120.

(Comparative Example 2)
It is the same as Comparative Example 1 except that each of the three annular magnet bodies 121, 120, 121 is configured using six fan-shaped magnets having a central angle of 60 degrees.

  For each of the pulley structures of Examples 1 to 5 and Comparative Examples 1 and 2 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.

  As shown in FIG. 14, in Examples 1 to 5 in which a magnet magnetized in the circumferential direction and a magnetic material are combined, in comparison with Comparative Examples 1 and 2 configured only with magnets magnetized in the rotation axis direction, The initial torque change rate (slope) with a small rotation angle is small. That is, the torque when the difference in rotational speed between the pulley 2 and the hub 3 is small is kept small, and resonance is unlikely to occur.

  In addition, the center angle of the magnetic body is larger than the center angle of the magnet, and in Examples 1 to 4, the center angle of the magnetic body is the largest. Is the smallest. It can also be seen that the smaller the central angle of the magnetic material, the larger the initial torque change rate (Example 1: about 0.1 Nm / degree, Example 2: about 0.2 Nm / degree, Example 3: About 0.35 Nm / degree, Example 4: about 0.8 Nm / degree). From this, it is possible to adjust the rate of change of torque within a range where the phase difference is small by changing the central angle of the magnetic body.

  Moreover, when Example 5 and Comparative Example 2 are compared with the case where Examples 1-4 and Comparative Example 1 are compared, Example 5 has a small initial torque change rate with a small rotation angle, and rotation. When the angle becomes larger, a larger torque can be obtained as compared with Comparative Example 2 (the maximum torque of Examples 1 to 4 is about 8 Nm with respect to the maximum torque of about 14 Nm of Comparative Example 1, and the maximum torque of Comparative Example 2 is about The maximum torque of Example 5 is about 12 Nm for 11.5 Nm). As described above, in the fifth embodiment, when the rotational angle difference between the pulley and the hub is small, the torque acting to eliminate the rotational speed difference is prevented from being excessive, and the rotational speed difference is large. It can be seen that rotation fluctuation can be attenuated quickly by applying a large torque.

1, 1A, 1B Pulley structure 2, 2A, 2B Pulley 3, 3A, 3B Hub 17, 17B First magnet 18, 18B Second magnet 25, 25B Magnetic body 26, 26B Magnetic body

Claims (5)

A first rotating body;
A second rotating body rotatable relative to the first rotating body;
A first magnet provided on the first rotating body;
A second magnet provided on the second rotating body so as to sandwich the first magnet in the direction of the rotation axis, and capable of opposing the first magnet in the direction of the rotation axis ;
At least one of the first magnet and the second magnet is magnetized in the circumferential direction, and a plurality of the magnets are arranged in the circumferential direction with the magnetic material interposed therebetween.
2. A pulley structure characterized in that two magnets sandwiching the magnetic body in the circumferential direction have the same magnetic pole on the magnetic body side. The first rotating body is provided with a plurality of the first magnets, and the plurality of first magnets and the magnetic body are alternately arranged in the circumferential direction,
The plurality of second magnets are also provided in the second rotating body, and the plurality of second magnets and the magnetic body are alternately arranged in a circumferential direction. Pulley structure. The pulley structure according to claim 2, wherein a center angle of the magnetic body is 0.8 times or more of a center angle of the one magnet. The other of the first magnet and the second magnet is arranged in the circumferential direction without sandwiching the magnetic body,
2. The pulley according to claim 1, wherein the plurality of the other magnets are arranged such that the magnetic poles on the surface facing the one magnet are opposite between the magnets adjacent in the circumferential direction. Structure. The pulley structure according to any one of claims 1 to 4 , wherein the one magnet and the magnetic body are alternately arranged in a circumferential direction to constitute an annular magnet body.

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