JP2010174908A - Pulley structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulley structure, capable of quickly depressing rotational fluctuation caused in a rotator without using a rubber elastic material. <P>SOLUTION: The pulley structure 1 includes a pulley 2 around which a belt 106 is wrapped; a hub 3 rotatable relative to the pulley 2; a first annular magnet unit 20 provided on the pulley 2 and composed of three first magnets 17 and three magnetic bodies 25 disposed alternately in the circumferential direction; and a second annular magnet unit 21 provided on the hub 3 and composed of three second magnets 18 and three magnetic bodies 26 disposed alternately in the circumferential direction. <P>COPYRIGHT: (C)2010,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 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 pulley structure according to a first aspect of the invention includes 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 first rotating body. The two-rotor has a second magnet provided so as to be able to face the first magnet, and at least one of the first magnet and the second magnet has a magnetic body aligned in the circumferential direction. Is arranged.

  According to the configuration of the present invention, the first rotating body and the second rotating body are relatively rotated by the magnetic flux between the first magnet provided on the first rotating body and the second magnet provided on the second rotating body. Connected in a possible state. 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.

  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, at least one of the first magnet and the second magnet is provided with a magnetic body so as to be aligned along the circumferential direction. Therefore, when a relatively small rotational speed difference (phase difference) occurs between the first rotating body and the second rotating body, the phases of the first and second magnets facing each other shift, A magnet will face the magnetic body adjacent to the other magnet in the circumferential direction. At this time, as described above, a magnetic force is generated between the first magnet and the second magnet that are out of phase so as to reduce the rotational speed difference. The magnetic force in the direction of repulsion (that is, the direction of reducing the difference in rotational speed) does not act greatly between the magnets having different polarities. 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. In addition, when the magnetic body and the magnet face each other, a reverse magnetic field does not act on the magnet between the magnetic body and the demagnetization of the magnet due to the reverse magnetic field can be prevented.

  A pulley structure according to a second invention is characterized in that, in the first invention, at least one of the first magnet and the second magnet is sandwiched between the magnetic bodies in the circumferential direction. .

  According to this configuration, even if the rotational speed difference (phase difference) between the first rotating body and the second rotating body occurs in any of the two circumferential directions, one of the first magnet and the second magnet. This magnet is opposed to the magnetic body adjacent to the other magnet in the circumferential direction, so that the torque that acts to eliminate the rotational speed difference between the two rotating bodies is suppressed from becoming too large. .

  The pulley structure according to a third aspect of the present invention is the pulley structure according to the second 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 the 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.

  The pulley structure according to a fourth invention is the pulley structure according to the third invention, wherein the magnetic poles of the plurality of first magnets on the surface facing the second magnet are all equal, and the first magnet of the plurality of second magnets is the first one. The magnetic poles on the surface facing the magnet are all equal and are different from the magnetic poles of the first magnet.

  Since the magnetic poles of the opposing surfaces of the plurality of first magnets are all the same, and the magnetic poles of the opposing surfaces of the plurality of second magnets are all the same, and are different from the magnetic poles of the first magnets, all the first magnets And since a reverse magnetic field does not act on a 2nd magnet and an irreversible demagnetization by this reverse magnetic field does not arise, degradation of the attenuation function of a rotation fluctuation is suppressed.

  A 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 first rotating body and the second rotating body are made of a nonmagnetic material, and the first magnet and the second magnet At least one of these is attached to the corresponding rotating body via a support member made of a magnetic material.

  When the first rotating body and the second rotating body are formed of a magnetic material, the magnetic flux generated from the first magnet and the second magnet passes through the inside of the first rotating body and the second rotating body, and both magnets. The closed circuit that does not pass through the gap is formed, and there is a problem that the energy of the magnet cannot be used efficiently. However, if the first rotator and the second rotator are made of a nonmagnetic material, the first rotator and the second rotator made of a nonmagnetic material from surfaces other than the opposing surfaces of the first magnet and the second magnet. There is a problem that a large amount of magnetic flux leaks to the outside through the. Therefore, in the present invention, the first rotating body and the second rotating body are formed of a nonmagnetic material, and at least one of the first magnet and the second magnet is made of a magnetic material for the corresponding rotating body. The support member is attached via a support member, and the support member made of the magnetic material serves as a yoke for guiding a magnetic flux so as to pass between the first magnet and the second magnet. In other words, the leakage of magnetic flux from the first magnet and the second magnet other than the opposing surfaces is suppressed as much as possible, and the energy of the magnetic force generated by the first magnet and the second magnet is effectively between the first magnet and the second magnet. Therefore, torque can be efficiently transmitted between the first rotating body and the second rotating body.

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 three 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 three annular magnet bodies when there exists a rotational speed difference between a pulley and a hub. It is a perspective view of the annular magnet body comprised only with the magnet. 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 of another modification. It is a figure which shows the circumferential direction arrangement | positioning of the magnet and magnetic body of another modified 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. 12 from the rotation axis direction. It is a perspective view of the annular magnet body of another modification. It is a graph which shows the relationship between the rotation angle of the pulley structure of Example 1, and a torque. It is a graph which shows the relationship between the rotation angle of the pulley structure of Example 2, and a torque. It is a graph which shows the relationship between the rotation angle of the pulley structure of Example 3, and a torque. It is a graph which shows the relationship between the rotation angle of the pulley structure of the comparative example 1, 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. A drive pulley 105, a driven pulley 104, and a transmission belt 106 that is stretched across 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 inner side 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. As shown in FIGS. 3 and 4, the first annular magnet body 20 is fixed to the pulley 2 on the outer peripheral surface thereof. The first annular magnet body 20 is composed of three first magnets 17 and a magnetic body 25 made of three 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 (60 degrees), and the three first magnets 17 and the three 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 three second magnets 18 and a magnetic body 26 made of three 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 (60 degrees), and the three second magnets 18 and the three 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.

  Furthermore, the first magnet 17 and the second magnet 18 are each magnetized in the rotation axis direction. The three first magnets 17 constituting the first annular magnet body 20 all have N poles on the base side (left side in FIGS. 2 and 3), and the tip side surface (FIGS. 2 and 2). The magnetic pole on the surface 3) is the S pole. Similarly, all of the three second magnets 18 constituting the second annular magnet body 21 have N poles on the base side surface and S poles on the tip side surface.

  In other words, the magnetic poles of the three first magnets 17 constituting the first annular magnet body 20 on the surface facing the second magnet 18 are all equal. Further, the magnetic poles of the three second magnets 18 constituting the second annular magnet body 21 on the surface facing the first magnet 17 are all the same and are different from the magnetic poles of the first magnet 17. Therefore, a magnetic force in the direction of attraction always acts between the first magnet 17 and the second magnet 18.

  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 directly attached to the inner surface of the pulley 2. . 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 second annular magnet bodies 21 located outside in the rotation axis direction are attached to the outer peripheral surface of the hub 3 (cylindrical member 3b) through two annular support members 22 and 23, respectively. As a method for 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 of attaching the two second annular magnet bodies 21 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 support members 22 and 23 cover the surface of the second annular magnet body 21 (second magnet 18), which is a support target, on the opposite side of the surface facing the first annular magnet body 20 (first magnet 17). Is provided. 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 side surface in the drawing) of the second annular magnet body 21, and the support member 23 on the tip end side is the second annular magnet. The front surface of the body 21 (the right surface 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).

  Of the two support members 22, 23, the support member 23 that supports the second annular magnet body 21 (second magnet 18) on the tip side (right side in FIG. 2) is the outer surface of the second annular magnet body 21. Is also covered. In addition, an annular sliding member 24 is provided on the inner surface of the pulley 2, and the outer peripheral portion 23 a of the support member 23 covering the second annular magnet body 21 slides and rotates with respect to the sliding member 24. It has become. 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. As shown in FIG. 4, when there is no rotational speed difference (phase difference) between the pulley 2 and the hub 3, the three first magnets 17 of the first annular magnet body 20 fixed to the pulley 2 and the hub 3. The three 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 three second annular magnet bodies 21, 20, 21 when there is no rotational speed difference between the pulley 2 and the hub 3. In addition, in FIG. 5, the figure which looked at one magnet and two magnets arrange | positioned so that it may be pinched | interposed in the circumferential direction contained in each annular magnet body 21,20,21 from the radial direction of the annular magnet body Is shown.

  As shown in FIG. 5, when 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 and the second magnet 20 of the first annular magnet body 20 are rotated. The circumferential positions of the second magnets 18 of the annular magnet body 21 are the same, and both the magnets 17 and 18 face each other. At this time, the magnetic flux B emitted from the N pole of the magnet reaches the S pole through the support members 22 and 23 made of a magnetic material and the magnetic bodies 25 and 26 arranged so as to sandwich the magnet in the circumferential direction. However, the direction of the magnetic flux B between the two annular magnet bodies 20 and 21 is parallel to the rotation axis 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.

  When this rotational speed difference is relatively small, as shown in FIG. 6, the circumferential positions of the three first magnets 17 and the three second magnets 18 are slightly shifted from each other. The magnetic body 26 that is adjacent to the second magnet 18 in the circumferential direction is partially opposed.

  FIG. 7 is a diagram schematically showing the flow of magnetic flux between the three annular magnet bodies 21, 20, 21 in a state where a rotational speed difference is generated between the pulley 2 and the hub 3. As shown in FIG. 7, when the circumferential positions of the first magnet 17 and the second magnet 18 are shifted, the direction of the magnetic flux B flowing between the first annular magnet body 20 and the second annular magnet body 21 is A magnetic force acts between the first magnet 17 and the second magnet 18 so as to eliminate a circumferential positional shift (phase difference). Therefore, a rotational speed difference becomes small between the pulley 2 to which the first magnet 17 (first annular magnet body 20) is fixed and the hub 3 to which the second magnet 18 (second annular magnet body 21) is fixed. Torque is generated as follows. Thereby, the rotational fluctuation generated in the pulley 2 is attenuated when it is transmitted to the hub 3.

  As described above, the magnetic force between the first magnet 17 and the second magnet 18 that acts to reduce the rotational speed difference between the pulley 2 and the hub 3 is a rotational fluctuation suppression caused by a conventionally known eddy current. It is much more powerful than power. Therefore, it is possible to quickly attenuate the rotational fluctuation generated in the hub 3. Further, 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.

  By the way, in this embodiment, the 1st annular magnet body 20 and the 2nd annular magnet body 21 are magnets in which permanent magnets (first magnet 17 and second magnet 18) and magnetic bodies 25 and 26 are alternately arranged. However, it is also conceivable that an annular magnet body is composed of only permanent magnets. For example, as shown in FIG. 8, by using permanent magnets instead of the magnetic bodies 25 and 26, the annular magnet bodies 120 and 121 are made up of only six magnets 17 and 18 having different magnetic poles between magnets adjacent in the circumferential direction. Constitute. Even with this configuration, it is possible to achieve the effect of generating torque that reduces the difference in rotational speed between the annular magnet bodies 20 and 21 as described above.

  However, the configuration shown in FIG. 8 has the following problems. That is, when a rotational speed difference occurs between the pulley 2 and the hub 3 (between the two annular magnet bodies 120 and 121), the first magnet 17 and the second magnet 18 having the same magnetic pole face each other. Become. Therefore, in addition to the magnetic force in the attracting direction between the first magnet 17 and the second magnet 18 having different polarities, a repulsive magnetic force acts between the first magnet 17 and the second magnet 18 having the same polarity. Thus, even when the rotational speed difference (phase difference) is small, the torque acting on the pulley 2 and the hub 3 in a direction to eliminate the rotational speed difference becomes very large. Thus, if the torque for eliminating this is too large for a small rotational speed difference, resonance may occur between the pulley 2 and the hub 3. Therefore, it is preferable that the relationship between the rotational speed difference (phase difference) and the torque is close to a linear relationship so that when the rotational speed difference (phase difference) is small, the torque for eliminating the difference is also small.

  Further, in the configuration of FIG. 8, when a rotational speed difference is generated between the pulley 2 and the hub 3 and the first magnet 17 and the second magnet 18 having the same polarity face each other, A magnetic field (reverse magnetic field) from the opposing magnet acts on each of the two magnets 18. For this reason, this reverse magnetic field causes irreversible demagnetization in both the first magnet 17 and the second magnet 18, and as a result, the rotational fluctuation damping function of the pulley structure 1 may be degraded.

  On the other hand, in the pulley structure 1 of the present embodiment, the magnetic bodies 25 and 26 arranged along the circumferential direction with the first magnet 17 and the second magnet 18 are provided. When a relatively small rotational speed difference is generated between the pulley 2 and the hub 3, each magnet 17 (18) has a magnetic body 26 (25) adjacent to the magnet 18 (17) that originally faced the magnet 17 (18). However, no magnetic force acts between the magnetic body 26 (25) and the magnet 17 (18) in the repulsive direction (that is, the direction in which the phase difference is eliminated). Therefore, when the rotational speed difference (phase difference) is small, the torque that acts to eliminate this rotational speed difference does not become too large, and resonance between the pulley 2 and the hub 3 is prevented. it can. The reverse magnetic field acting on the magnet 17 (18) is smaller than that of the configuration of FIG.

  Further, when a rotational speed difference is generated between the pulley 2 and the hub 3 and the magnet and the magnetic body face each other, unlike the case where the magnets 17 and 18 having the same polarity face each other, an unnecessary external magnetic field ( The reverse magnetic field does not act on the magnets 17 and 18. Accordingly, it is possible to prevent the irreversible demagnetization from occurring in the magnets 17 and 18 and the rotational fluctuation attenuation function from being lowered.

  In the present embodiment, the three first magnets 17 and the three magnetic bodies 25, and the three second magnets 18 and the three magnetic bodies 26 are alternately arranged in the circumferential direction, whereby the first magnet 17 and the second magnet 18 are sandwiched between the magnetic bodies 25 and 26 in the circumferential direction, respectively. Therefore, even if the rotational speed difference between the pulley 2 and the hub 3 occurs in any of the two circumferential directions, the first magnet 17 and the second magnet 18 face the magnetic bodies 25 and 26. Therefore, it is possible to suppress the torque acting so as to eliminate the rotational speed difference from becoming too large. Further, since the three first magnets 17 and the three second magnets 18 are distributed in the circumferential direction, an equal torque can be applied in the circumferential direction between the pulley 2 and the hub 3. .

  In the pulley structure 1 of the present embodiment, as described above, the pulley 2 provided with the first magnet 17 (first annular magnet body 20) and the second magnet 18 (second annular magnet body 21). Each of the hubs 3 provided with is made of a nonmagnetic material. However, in this case, a large amount of magnetic flux leaks to the outside through the pulley 2 and the hub 3 made of a nonmagnetic material from surfaces other than the opposing surfaces of the first magnet 17 and the second magnet 18. As shown in FIGS. 2, 5, and 7, the second magnet 18 (second annular magnet body 21) provided so as to sandwich the first magnet 17 is attached to the hub 3 by support members 22 and 23 made of a magnetic material. It is attached.

  The two support members 22, 23 made of these magnetic materials serve as a yoke for guiding magnetic flux so as to pass between the first magnet 17 and the second magnet 18, and the first magnet 17 and the second magnet 18. Magnetic flux leakage from surfaces other than the opposing surfaces of each other is suppressed as much as possible, and the energy of magnetic force generated by the first magnet 17 and the second magnet 18 is effectively applied between the first magnet 17 and the second magnet 18. be able to. As a result, torque can be efficiently transmitted between the pulley 2 and the hub 3.

  As shown in FIG. 2, the first annular magnet bodies 20 (first magnets 17) and the two second annular magnet bodies 21 (second magnets 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 torque is generated between the two. It will be possible to communicate reliably. In addition, two second annular magnet bodies 21 arranged on both outer sides of the three annular magnet bodies 21, 20, 21 arranged in the rotation axis direction are on the opposite side to the surface facing the first annular magnet body 20. The surface is covered with support members 22 and 23. Therefore, it is possible to reliably prevent a part of the magnetic flux from leaking from the surface opposite to the facing surface of the second magnet 18 in the rotation axis direction (the direction opposite to the first magnet 17). Further, as shown in FIG. 2, the one support member 23 also covers the outer surface of the second annular magnet body 21. Thereby, it becomes a bearing of the sliding member 24.

  In the present embodiment, the three first magnets 17 and the three 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. 9, the number of the first annular magnet bodies 20 and the second annular magnet bodies 21 arranged in the direction of the rotation axis C may 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.

  The number of magnets 17 and 18 constituting one annular magnet body 20 and 21 is not necessarily three, 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 60 degrees, and may be changed to other angles such as 45 degrees and 30 degrees. Further, as shown in FIG. 10, the annular magnet body 20 (21) may be configured by only one magnet 17 (18) and one magnetic body 25 (26) having a central angle of 180 degrees. 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.

  Furthermore, it is not necessary to arrange the magnets 17 and 18 and the magnetic bodies 25 and 26 over the entire circumference in the circumferential direction to form an annular magnet body, and as shown in FIG. The structure by which the magnetic body 25 (26) is arrange | positioned may be sufficient. Further, it is not necessary to arrange the magnetic body 25 (26) on both sides in the circumferential direction with respect to one magnet 17 (18), and the magnetic body 25 (26) only on one side in the circumferential direction as shown in FIG. May be arranged.

  Further, the magnetic bodies 25 and 26 are not necessarily arranged in the circumferential direction with respect to both the first magnet 17 and the second magnet 18, and the magnetic body is provided only in one of the first magnet 17 and the second magnet 18. It may be provided.

  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. 12, 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. 13, the first annular magnet body 20B located on the outer side is composed of three first magnets 17B and three magnetic bodies 25B arranged alternately in the circumferential direction. The three first magnets 17B are magnetized in the radial direction, the inner peripheral surface facing the inner second annular magnet body 21B is an N pole, and the outer peripheral surface is an S pole. The second annular magnet body 21B located on the inner side includes three second magnets 18B and three magnetic bodies 26B arranged alternately in the circumferential direction. The three second magnets 18B are also magnetized in the radial direction, and the outer peripheral surface facing the outer first annular magnet body 20B is the S pole and the inner peripheral surface is the N pole.

  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. Due to the magnetic force in the attracting direction acting between the two types of magnets 17B and 18B, a torque in a direction to eliminate the rotational speed difference is generated between the pulley 2B and the hub 3B. Further, when a rotational speed difference is generated between the pulley 2B and the hub 3B, the magnet 17B (18B) and the magnetic body 25B (26B) are partially opposed to each other, so that the rotational speed difference is excessively increased. No torque is generated.

  3] In the above embodiment, the magnetic poles of the plurality of magnets 17 and 18 constituting the annular magnet bodies 20 and 21 (the magnetic poles facing the other annular magnet bodies) are all the same, but are shown in FIG. Thus, the magnetic poles of the plurality of magnets may be different. In this case, when the first magnet 17 and the second magnet 18 are displaced in the circumferential direction, the magnetic field (reverse magnetic field) of the other magnet 18 (17) having the same polarity is slightly increased in one magnet 17 (18). Although it may act, since the plurality of magnets 17 (18) included in the annular magnet body 20 (21) are arranged in the circumferential direction with the magnetic body 25 (26) interposed therebetween, The first magnet 17 and the second magnet 18 having the same polarity do not often face each other directly. Therefore, even if a reverse magnetic field acts on the magnets 17 and 18, demagnetization of the magnets 17 and 18 hardly occurs.

  4] 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.

  5] In the above embodiment, the support members 22 and 23 for attaching the second magnet 18 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 on the pulley 2, a neodymium magnet having a fan shape with an outer diameter of 58 mm, an inner diameter of 26 mm, and a central angle of 45 degrees and magnetized in the direction of the rotation axis was used. The magnetic body 25 combined with the first magnet 17 was made of S25C material formed in the same shape as the first magnet 17. Then, one first annular magnet body 20 in which the four first magnets 17 and the four 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 having a fan shape with an outer diameter of 56 mm, an inner diameter of 24 mm, and a central angle of 45 degrees and magnetized in the direction of the rotation axis was used. Further, the magnetic body 26 combined with the second magnet 18 was made of S25C material formed in the same shape as the second magnet 18. Then, two second annular magnet bodies 21 in which four second magnets 18 and four magnetic bodies 26 are alternately arranged in the circumferential direction were produced. Further, an S25C material (support members 22 and 23) having an outer diameter of 56 mm, an inner diameter of 24 mm, and a thickness of 5 mm is provided on the N pole side of one second annular magnet body 21 and the S pole side of the other second annular magnet body 21. Laminated as a back yoke.

  One first annular magnet body 20 is sandwiched between two second annular magnet bodies 21 so that the magnetization directions (positions of magnetic poles) are the same. In addition, the arrangement | positioning space | interval of the three annular magnet bodies 21, 20, and 21 was 0.5 mm. These three annular magnet bodies were attached to the pulley 2 and the hub 3 shown in FIG. 1 to produce a pulley structure.

(Example 2)
The same specifications as in Example 1 were used except that the outer diameter of the first magnet 17 was 68 mm and the outer diameter of the second magnet 18 was 66 mm.

(Example 3)
The central angle of the first magnet 17, the second magnet 18, and the magnetic bodies 25, 26 combined with both magnets is 30 degrees, and the number of circumferential arrangements of the magnets 17, 18 and the magnetic bodies 25, 26 is six. Except for this, the specifications were the same as in Example 1.

(Comparative Example 1)
In the first embodiment, the magnetic bodies 25 and 26 of S25C arranged side by side with the first magnet 17 and the second magnet 18 in the circumferential direction are different from those of the adjacent first magnet 17 and the second magnet 18 in which the magnetic poles are opposite to each other. It replaced with the magnet (namely, the structure of FIG. 8 where the annular magnet body was comprised only with the magnet). Other than the above, the specifications were the same as those in Example 1.

  For each of the pulley structures of Examples 1 to 3 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 results are shown in FIGS.

  In Examples 1 to 3 (FIGS. 15 to 17) in which a magnet and a magnetic material are combined, the phase difference (rotation angle) between the pulley and the hub and the torque have a substantially linear relationship in a wide phase difference range. In other words, the torsion spring constant does not change so much due to the phase difference. Therefore, since the torque when the phase difference is small is suppressed, resonance hardly occurs. On the other hand, in Comparative Example 1 (FIG. 18) using only magnets, it can be seen that the rate of torque change when the phase difference is small is very large, and even with a slight phase difference, a large torque acts and resonance occurs. It becomes easy.

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 26 , 26B Magnetic material

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 be able to face the first magnet;
Have
In at least one of the first magnet and the second magnet, a magnetic body is arranged so as to be aligned along the circumferential direction.   The pulley structure according to claim 1, wherein at least one of the first magnet and the second magnet is sandwiched between the magnetic bodies in a circumferential direction. 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 magnetic poles on the surface of the plurality of first magnets facing the second magnet are all equal,
4. The pulley structure according to claim 3, wherein all of the magnetic poles of the plurality of second magnets on the surface facing the first magnet are equal and different from the magnetic poles of the first magnet. The first rotating body and the second rotating body are made of a nonmagnetic material,
The at least one of the first magnet and the second magnet is attached to the corresponding rotating body via a support member made of a magnetic material. Pulley structure.

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