Abstract:
The present invention aims to provide an electromagnetic clutch capable of decreasing the impact noise generated when the armature plate and the driving rotor are coupled. The present invention further aims to provide a compressor equipped with this electromagnetic clutch. 
     An electromagnetic clutch in the present invention comprises a driving rotor including a coil, and an armature having an armature plate that is disposed facing this driving rotor and having the same axis of rotational thereas, and when a voltage is applied to excite coil, the end face of driving rotor and the armature plate are attached together by coil&#39;s magnetic force, thereby coupling driving rotor and armature. Armature plate comprises a plurality of metal thin plates (plate members) laminated together, and at least a part of the plate members being connected each other.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an electromagnetic clutch, and more preferably, to an electromagnetic clutch employed in a compressor that is assembled into an air conditioner in a vehicle or the like. 
     2. Description of the Related Art 
     FIG. 16 is a view in longitudinal section showing an example of a conventional electromagnetic clutch. 
     This electromagnetic clutch  100  is provided in a compressor, such as an air conditioner in a vehicle or the like. Electromagnetic clutch  100  mechanically and intermittently connects this compressor and a driving source not shown in the Figure. Electromagnetic clutch  100  is disposed in the nose portion  101  of the front case of the compressor. 
     A driving rotor  103  is supported in a freely rotating manner at the outer periphery of nose portion  101  via clutch shaft bearing  102 . A coil  104  is included inside driving rotor  103 . Armature plate  105  is coaxially disposed so as to be facing said driving rotor  103 . 
     Hub  106  is fixed in place by a nut  107  to the projecting portion of drive shaft  112  of the compressor. One end of connecting plate  108  is fixed in place to this hub  106  by rivet  110 , while the other end is fixed to armature plate  105  via rivet  109 . Electromagnetic clutch  100  is composed of clutch shaft bearing  102 , driving rotor  103 , coil  104 , armature plate  105 , hub  106 , connecting plate  108 , and rivets  109  and  110  as main parts thereof. 
     A belt pulley  111  is provided at the outer periphery of driving rotor  103  and is connected to a driving source such as an engine via a V belt that is wrapped around belt pulley  111  but is not shown in the figures. 
     In an electromagnetic clutch  100  of this design, the driving rotor  103  is connected to a driving source such as an engine, so that it is constantly rotating when the driving source is rotating. When electricity is sent through coil  104  and excites it in this state, armature plate  105  attaches to driving rotor  103  as a result of the magnetic force of coil  104 . A rotating torque of the driving source is communicated to drive shaft  111  via, in sequence, driving rotor  103 , armature plate  105 , rivet  109 , connecting plate  108 , rivet  110 , and hub  106 . Drive shaft  112  of the compressor element is rotated as a result. 
     In this state, when electricity ceases to be sent through coil  104 , armature plate  105  separates from driving rotor  103 , and the transmission of power to drive shaft  112  is interrupted. 
     In the electromagnetic clutch  100 , the armature plate  105  is made of metal and is formed as a thick plate having a unitary structure. Driving rotor  103  is also formed as a unitary structure from a metal material. When electricity is passed through coil  104  and armature plate  105  is attached to driving rotor  103  due to the magnetic force of coil  104 , armature plate  105  is coupled to driving rotor  103  at high speed so as to minimize the relative slipping time between armature plate  105  and the end face of driving rotor  103 . For this reason, a problematic noise is generated when electricity is sent through coil  104 , so that coil  104  is excited and the armature plate  105  makes contact with an end face of the driving rotor  103 . 
     SUMMARY OF THE INVENTION 
     The present invention was conceived in view of the above-described problems, and has as its objective the provision of an electromagnetic clutch capable of decreasing the noise generated when the armature plate makes contact with the driving rotor. The present invention further aims to provide a compressor equipped with this electromagnetic clutch. 
     The electromagnetic clutch in the present invention comprises a driving rotor that is connected so as to be linked to a driving source and that includes a coil, and an armature having an armature plate that is disposed facing this driving rotor and having the same axis of rotational thereas, wherein, when a voltage is applied to excite the coil, the end face of the driving rotor and the armature plate are attached or separated by the coil&#39;s magnetic force, thereby intermittently coupling the driving rotor and the armature. In said electromagnetic clutch, the armature plate comprises a plurality of plate members laminated together, and at least a part of each of the plate members being connected the other plate members. 
     In this electromagnetic clutch, the armature plate is formed by laminating together a plurality of plate members. As a result, air layers are formed in between each of the plate members. For this reason, a force generated when the armature plate makes contact with the end face of the driving rotor is absorbed and reduced through the vibration of the individual plate members of the armature plate. 
     In addition, because the armature plate comprises a plurality of plate members laminated together, the armature plate is less rigid as compared to conventional armature plates which consist of a thick plate formed as a unitary structure. Thus, the force generated when the armature plate makes contact with the end face of the driving rotor is absorbed and reduced. 
     In the electromagnetic clutch, each of the plate members has the same thickness. 
     Because each of the plate members is of equal thickness in this electromagnetic clutch, numerous plate members can be formed easily. As a result, the cost of the armature plate is decreased. 
     In said electromagnetic clutch, among the various plate members, the plate member that comes in contact with the end face of the driving rotor is of a different thickness than the other plate members. 
     The magnetic force generated by the armature plate is controlled by on the thickness of the plate member that comes in contact with the driving rotor. Accordingly, when the thickness of the plate member that comes in contact with the end face of the driving rotor is increased in this electromagnetic clutch, the magnetic flux generated by the coil passes easily through the plate members. Thus, the magnetic force generated at the armature plate becomes greater, and, as a result, the clutch torque increases. 
     Conversely, if the plate that comes in contact with the end face of the driving rotor is made thinner, then the plate members are less rigid. Therefore, the force generated when the armature plate makes contact with the end face of the driving rotor is reduced. 
     In the electromagnetic clutch, among the plate members, the plate member that comes in contact with the end face of the driving rotor is thicker than the other plate members. 
     Because the plate member that comes in contact with the end face of the driving rotor is in sliding contact with the end face of the driving rotor, it experiences more severe abrasion than the other plate members. Accordingly, in this electromagnetic clutch, the plate member that comes in contact with the end face of the driving rotor is made thicker than the other plate members. 
     In the electromagnetic clutch, the various plate members forming the armature plate are roughly ring-shaped and made of a metal material, and are fixed in place by welding at a plurality of sites on the outer periphery, or on the outer and inner peripheries, of the plate members. 
     By suitably welding a plurality of sites on the outer periphery, or on the outer and inner peripheries, of the plate members, the various plate members are conveniently fixed in place. 
     In addition, in the electromagnetic clutch in the present invention, the various plate members forming the armature plate are roughly ring-shaped, and are fixed in place by caulking at a variety of sites on the end face of the plate members. 
     By employing caulking, it is possible to fix the plate members securely without carrying out a thermal treatment such as welding. 
     The electromagnetic clutch comprises a driving rotor, that includes a coil and is connected so as to be linked to a driving source, and an armature, that has an armature plate that is disposed so as to face the driving rotor and has the same axis of rotation thereas, and the end face of the driving rotor and the armature plate are attached together or are separated by the coil&#39;s magnetic force when the coil is excited due to voltage impression, thereby intermittently linking and connecting the driving rotor and the armature. In this electromagnetic clutch, the driving rotor has a main body portion formed in a unitary manner and a wall portion that forms the end face of the driving rotor, the wall portion comprises laminating a plurality of plate members, and at least a part of each of said plate members being connected to the other plate members. 
     The wall portion forming the end face of the driving rotor in this electromagnetic clutch is formed by laminating a plurality of plate members together. As a result, air layers are formed between each of the plate members, and a driving rotor end face is formed that has a low eigenvalue (spring constant). For this reason, the force generated when the end face of the driving rotor couples with the armature plate is absorbed and reduced due to the vibration of the individual plate members that form the wall portion on the end face side of the driving rotor. 
     In addition, the wall portion forming the end face of the driving rotor comprises a plurality of plate members laminated together. Thus, the driving rotor end face is less rigid than a conventional driving rotor end face that is formed to have a unitary structure. Thus, the force generated when the armature plate makes contact with the end face of the driving rotor is reduced. 
     In the electromagnetic clutch, each of the plate members has the same thickness. 
     By forming each of the plate members to have the same thickness in this electromagnetic clutch, a plurality of plate members can be easily formed. Thus, the cost of the driving rotor can be reduced. 
     In the electromagnetic clutch, among the plate members, the plate member that comes in contact with the armature plate is thicker than the other plate members. 
     The plate member that comes in contact with the armature plate is in sliding contact with the armature plate, so that it experiences more severe abrasion as compared to the other plate members. According, in this electromagnetic clutch, the plate member that comes in contact with the armature plate is thicker than the other plate members. 
     Further, in the present invention, each of the plate members is roughly ring-shaped and is formed of a metal material, and welding is performed to a plurality of sites on the outer periphery of the plate members or caulking is performed to outer peripheral sites on the end face of each of the plate members to fix the plate members to the outer peripheral side of the main body portion; and/or welding is performed to a plurality of sites on the inner periphery of the plate members or caulking is performed at inner peripheral sites on the end face of each of the plate members to fix the plate members to the inner peripheral side of the main body portion. 
     By welding or caulking on the outer peripheral side and/or the inner peripheral side of the plate members, each of the plate members can be conveniently fixed in place to the main body portion of the driving rotor. 
     In addition, in the present invention, the provision of the above-described armature plate and driving rotor. 
     In present invention, in a compressor for compressing a fluid using a compressor element, the power from the driving source that is mechanically connected to the driving rotor via the above-described electromagnetic clutch is communicated to the drive shaft of the compressor element that is mechanically connected to the armature. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a sectional view showing an embodiment of the compressor according to a first embodiment of the present invention. 
     FIG. 2 is a lateral view of the armature plate shown in FIG.  1 . 
     FIG. 3 is a plan view of the metal thin plate forming the armature plate in FIG.  2 . 
     FIG. 4 is a plan view of the friction plate forming the armature plate in FIG.  2 . 
     FIG. 5 is a plan view of the metal thin plate showing the means for fixing each of the metal thin plates shown in FIG.  3 . 
     FIG. 6 is a view showing the level of noise generated when the armature plate and the driving rotor end face couple through a comparison with the conventional design. 
     FIG. 7 is a plan view of the metal thin plates shown as a modification of the means for fixing each of the metal thin plates shown in FIG.  5 . 
     FIG. 8 is a plan view of the metal thin plates shown as a modification of the means for fixing each of the metal thin plates shown in FIG.  5 . 
     FIG. 9 is a plan view of the metal thin plates shown as a modification of the means for fixing each of the metal thin plates shown in FIG.  5 . 
     FIG. 10 is a plan view of the metal thin plates shown as a modification of the means for fixing each of the metal thin plates shown in FIG.  5 . 
     FIG. 11 is a side view showing a modification of the armature plate shown in FIG.  2 . 
     FIG. 12 is a side view of the driving rotor according to a second embodiment of the present invention. 
     FIG. 13 is a plan view of the metal thin plates forming the wall portion on the end face side of the driving rotor in FIG. 12, and is a view showing the means for fixing in place each of the metal thin plates. 
     FIG. 14 is a plan view of the metal thin plates shown as a modification of the means for fixing each of the thin metal plates shown in FIG.  13 . 
     FIG. 15 is a plan view of the metal thin plates shown as a modification of the means for fixing each of the thin metal plates shown in FIG.  13 . 
     FIG. 16 is a sectional view showing an example of a conventional electromagnetic clutch. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The first embodiment of the present invention will now be explained with reference to the accompanying figures. Note, however, that the present invention is not limited to these embodiments. 
     FIG. 1 is a view in longitudinal section showing an embodiment of a compressor according to the present invention. 
     In the compressor shown in FIG. 1, numeral  1  indicates a housing consisting of a cup-shaped main body  2  and a front case  3  fastened by a bolt not shown in the figure. 
     A scroll compressor element consisting of a fixed scroll  11  and a revolving scroll  12  is disposed inside cup-shaped main body  2 . 
     Fixed scroll  11  is provided with an end plate  13  and a spiral lap  14  that is provided projecting out from the inner surface of end plate  13 . End plate  13  is fastened to cup-shaped main body  2  by bolt  15 . Revolving scroll  12  is provided with end plate  16  and a spiral lap  17  that is provided projecting out from the inner surface of end plate  16 . The axes of the evolving scroll  12  and fixed scroll  11  are eccentrically separated from each other by a radius of revolving, that is, they are in an eccentric form. In addition, phases of these scrolls are different from each other by 180°, and these scrolls are engaged with each other. As a result, a plurality of closed small chambers  18   a,    18   b  are formed essentially at positions of point symmetry with respect to the center of the spiral. 
     Drive bush  21  is included so as to be freely rotating via revolving bearing  22  inside a cylindrical boss  20  which projects from the middle of the outer surface of end plate  16 . An eccentric drive pin  24 , which is provided projecting from the inner end of drive shaft  4 , engages in a freely rotating manner with eccentric hole  23  which is provided penetrating through this drive bush  21 . This drive shaft  4  projects to the outside passing through nose portion  5  of front case  3 , and is supported by front case  3  via shaft bearings  6  and  7 . 
     As shown in the figure, driving rotor  32  is supported in a freely rotating manner via a clutch shaft bearing  31  at the outer periphery of nose portion  5  of front case  3 . A coil  33  held in place by nose portion  5  via a fixing member is included in driving rotor  32 . In other words, driving rotor  32  is provided so as to be freely rotating with respect to coil  33  which is fixed in place. An armature plate  34  having the same axis is disposed facing this driving rotor  32 . 
     Hub  35  is fixed in place by nut  36  to the projecting portion of drive shaft  4  of this compressor. One end of connecting plate  37  is fixed in place to hub  35  by rivet  38 , and the other end of connecting plate  37  is fixed in place to armature plate  34  via rivet  39 . 
     Electromagnetic clutch  30  is composed of a clutch shaft bearing  31 , a driving rotor  32 , coil  33 , armature plate  34 , hub  35 , connecting plate  37 , and rivets  38  and  39  as main components thereof. An armature is formed of armature plate  34 , hub  35 , connecting plate  37 , and rivets  38 ,  39 . 
     A belt pulley  40  is provided to the outer periphery of driving rotor  32 , and is connected to a driving source such as an engine via a V-belt, not shown in the figures, which is wrapped around belt pulley  40 . 
     The compressor operates as follows. 
     Driving rotor  32  is connected to a driving source such as an engine via the V-belt. As a result, driving rotor  32  is constantly turning during the rotation of the engine or other such driving source. In this state, electricity is sent through coil  33 , exciting it. As a result, armature plate  34  attaches to end face  32   a  of driving rotor  32  due to the magnetic force of coil  33 . The rotation of driving rotor  32  is communicated by drive shaft  4  to armature plate  34 , rivet  39 , connecting plate  37 , rivet  38 , and hub  35  in sequence. Drive shaft  4  in this compressor mechanism is rotated. 
     When the transmission of electricity through coil  33  stops, armature  34  moves away from driving rotor  32  and transmission of power to drive shaft  4  is interrupted. 
     Drive shaft  4  is rotated, so that revolving scroll  12  is driven via eccentric drive pin  24 , drive bushing  21 , revolving bearing  22 , and boss  20 , and revolving scroll  12  is revolved and turned along a circular orbit, with auto-turning thereof prevented by rotation-blocking mechanism  25 . 
     A line-contact portion between spiral laps  14  and  17  are gradually moved toward the center of “swirl”. And thereby, the closed small chambers  18   a  and  18   b  also move toward the center of the swirl while the volume of each chamber is gradually reduced. Accordingly, gas, which flows into suction chamber  26  via an inlet port not shown in the figures is trapped inside closed small chambers  18   a  and  18   b  from the opening at the outer peripheral end between spiral laps  14  and  17 , and reaches small chamber  18   c  in the center while being compressed. The gas then passes through discharge port  61  which is provided penetrating through end plate  13  of fixed scroll  11 , pushes open discharge valve  62 , is discharged to discharge cavity  63 , and then flows out from here through discharge port  64 . 
     Next, an explanation of the electromagnetic clutch which is the characteristic portion of the present invention in a compressor of the above-described design will be explained with reference to FIGS. 2 to  4 . 
     FIG. 2 is a lateral view of the armature plate that forms the electromagnetic clutch. Armature plate  34  is formed by laminating a plurality of metal thin plates  41  which have a thickness on the order of 0.3 to 1.0 mm, for example. These metal thin plates  41  constitute a magnetic member employing, for example, S12, S15, S17, or SPCC (SPCC-E supplied by Nippon Steel Corp. may also be used). In addition, of these metal thin plates  41 , the metal thin plate that comes in contact with the end face of the driving rotor (i.e., the metal thin plate on the right side of the figure) will be referred to as friction plate  42 . 
     In this way, armature plate  34  is formed by laminating a plurality of metal thin plates  41  and then laminating friction plate  42  to the side that comes in contact with the driving rotor end face. 
     FIG. 3 is a plan view of a metal thin plate  41 . 
     Metal thin plate  41  is ring-shaped with a hollow center. Holes  43  for connecting with a connecting plate are provided on the same circumference at three sites that are at equivalent angles with respect to one another. In addition, respective long holes  44  are provided in between each connecting hole  43  and on the same circumference as connecting holes  43 . 
     FIG. 4 is a plan view of friction plate  42  which is the plate from among the metal thin plates  41  forming armature plate  34  that comes in contact with the end face of the driving rotor. 
     Friction plate  42  is designed such that concavities  45  are formed in the aforementioned metal thin plates  41 . With the exception of connecting holes  43 , long holes  44 , and concavities  45 , the remainder of friction plate  42  serves as the friction surface that is in contact with the end face of the driving rotor. 
     Armature plate  34  is fixed in place by laminating together friction plate  42  and a plurality of metal thin plates  41  shaped as described above, and then performing welding at multiple sites (three in this embodiment) P 1 , P 2 , and P 3  on the outer periphery of the metal thin plates and at multiple sites (two in this embodiment) Q 1  and Q 2  on the inner periphery of the metal thin plates as shown in FIG.  5 . The degree of welding is considered sufficient provided that the various metal thin plates  41  do not separate when the clutch torque is applied. By fixing armature plate  34  in this way, an air layer is formed in between each of the metal thin plates  41 . 
     This armature plate  34  is fixed to connecting plate  37  by a bolt  46 . 
     By forming armature plate  34  as described above, an air layer is formed in between each of the metal thin plates  41 . As a result, the impact which occurs when armature plate  34  couples with the end face of the driving rotor is attached and decreased due to the vibration of the various individual metal thin plates  41  that form armature plate  34 . 
     In addition, armature plate  34  is formed by laminating a plurality of metal thin plates  41 , so that the rigidity of armature plate  34  is less than the rigidity of conventional armature plates formed as a thick unitary structure. Thus, the force generated when armature plate  34  and the end of the driving rotor couple is absorbed and reduced. 
     Thus, the force generated when armature plate  34  makes contact with end face  32   a  of driving rotor  32  couple is decreased in said electromagnetic clutch  30 , and the noise generated when the armature plate  34  makes contact with the end face  32  is reduced. It is therefore possible to realize a compressor clutch and compressor in which there is little noise. 
     FIG. 6 shows the level of noise generated when the armature plate and the end face of the driving rotor couple. In this figures, the line indicated by the black circles shows the noise level where employing an armature plate formed by laminating together metal thin plates. The line indicated by the white circles shows the noise level when employing a conventional armature consisting of a thick plate formed in a unitary manner. According to this figure, if the noise level generated by the conventional armature plate is defined to be 1 at an rpm of 1000, a armature plate formed by metal thin plates laminated together is around 0.9. The noise level is decreased by about 10%. In this way, it was possible to confirm that said armature plate formed by metal thin plates laminated together is effective in reducing the noise generated by the armature plate. 
     Note that the first embodiment employed as the means for fixing in place the plurality of metal thin plates  41  a design in which welding was performed at a plurality of sites on the outer and inner peripheries of the metal thin plates  41  as shown in FIG.  5 . However, the same actions and effects can be realized for a design in which caulking  47  is performed to a plurality of sites on the end face of metal thin plates  41  to fix a plurality of the metal thin plates in place as shown in FIG.  7 . 
     Moreover, the same actions and effects are realized in the case of a design in which fixing is performed by welding only at a plurality of sites P 1 , P 2 , and P 3  on the outer periphery of metal thin plates  41  as shown in FIG. 8; a design in which fixing is performed by welding at a plurality of sites P 1 , P 2 , and P 3  on the outer periphery of metal thin plates  41  and performing caulking  47  to a plurality of sites on the end face of metal thin plates  41  as shown in FIG. 9; and a design in which fixing is performed by welding at a plurality of sites P 1 , P 2 , and P 3  on the outer periphery and at a plurality of sites Q 1  and Q 2  on the inner periphery of metal thin plates  41 , and performing caulking  47  to a plurality of sites on the end face of metal thin plates  41  as shown in FIG.  10 . 
     In other words, the means for fixing the plurality of metal thin plates is not particularly restricted in the present invention. Rather, the means employed is acceptable provided there is fixing in place to a sufficient degree such that the various metal thin plates  41  do not separate when a clutch torque is applied. Similarly, the welding site, the number of welding spots, the caulking site, and the number of caulking spots for fixing metal thin plates  41  in place may be selected as appropriate. 
     In the first embodiment, the friction plate has the same thickness as the other metal thin plates. However, it is also acceptable to vary the thickness of the friction plate as appropriate for the design considerations. 
     The armature place is made less rigid if the friction plate is made thinner. As a result, there is a reduction in the force generated when the armature plate and the driving rotor end face couple. 
     Conversely, the magnetic force generated by the armature plate is controlled by the thickness of the friction plate that comes in contact with the driving rotor. Accordingly, when the thickness of the friction plate is increased, the magnetic flux generated by the coil passes easily through the friction plate. Thus, the magnetic force generated at the armature plate becomes greater, and, as a result, the clutch torque increases. In addition, when the friction plate comes in contact with the driving rotor end face, it contacts the end face while sliding, so that hardly any abrading occurs. Accordingly, by making friction plate  42   a  thicker than the other metal thin plates  41  as shown in FIG. 11, it is possible to prevent damage to the armature plate and friction plate from abrasion. In this case, the thickness of the friction plate is preferably 0.5 mm or more greater than the other metal thin plates. 
     Accordingly, the thickness of the friction plate can be set according to the aforementioned considerations. 
     In addition, in the present embodiment, the metal thin plates and friction plate constitute a magnetic member employing, for example, S12, S15, S17, or SPCC (SPCC-E supplied by Nippon Steel Corp. may also be used). In addition, however, it is also acceptable to increase the clutch torque by employing such strong magnetic members as magnetic steel plate 50A1300, 50A1000 and the like. 
     The second embodiment of the present invention will now be explained with reference to FIGS. 12 and 13. 
     This embodiment differs from the first embodiment in that the wall portion forming the driving rotor end plate is formed by laminating metal thin plates. The armature  105  as shown in FIG. 16, or armature plate  34  as shown in FIG. 2 from the first embodiment may be used for this armature plate. 
     FIG. 12 is a lateral view of the driving rotor that forms the electromagnetic clutch. Driving rotor  32  has a main body portion  48  which is formed in a unitary manner and a wall portion  49  forming the end face. Wall portion  49  is formed by laminating a plurality of metal thin plates  50  which have a thickness on the order of 0.3 to 1.0 mm. These metal thin plates  50  constitute a magnetic member employing, for example, S12, S15, S17, or SPCC (SPCC-E supplied by Nippon Steel Corp. may also be used). 
     FIG. 13 is a plan view of a metal thin plate  50 . 
     Metal thin plate  50  is ring-shaped with a hollow center. Long holes  51  and  52  are provided intermittently over each circumferences of concentric circles with the metal thin plate  50 . 
     In driving rotor  32 , metal thin plates  50  are laminated together, and welding is performed at a plurality of sites (6 in this embodiment) P 4 , P 5 , P 6 , P 7 , P 8  and P 9  on the outer periphery and at a plurality of sites (4 in this embodiment) Q 3 , Q 4 , Q 5  and Q 6  on the inner periphery of the metal thin plates as shown in FIG. 13, to form a unitary structure with main body portion  48 . The degree of welding is considered sufficient provided that the various metal thin plates  50  do not separate when a clutch torque is applied. By fixing in this way, an air layer is formed in between each of metal thin plates  50 . 
     In said driving rotor  32 , an air layers are formed in between each of the metal thin plates  50 , and an end face  32   a  of driving rotor  32  is formed that has a low eigenvalue (spring constant). For this reason, the force generated when the end face  32   a  of driving rotor  32  couples with the armature plate is reduced through the vibration of the individual metal thin plates  50  that form the wall portion on the end face  32   a  side of the driving rotor. 
     In addition, end face  32   a  of driving rotor  32  is less rigid than the end face of the driving rotor in conventional designs that consist of a unitary structure. Thus, there is a reduction in the force generated when the armature plate and the end face  32   a  of the driving rotor  32  couple. 
     Thus, the force generated when the armature plate and end face  32   a  of driving rotor  32  couple is decreased in said electromagnetic clutch  30 , enabling a reduction in the noise generated when the armature plate makes contact with the end face  32   a  of driving rotor  32 . It is therefore possible to realize a compressor clutch and compressor in which there is little noise. 
     Note that the second embodiment employed as the means for fixing the plurality of metal thin plates  50  to a main body portion  48  a design in which welding was performed to a plurality of sites on the outer and inner peripheries of the metal thin plates  50  as shown in FIG.  13 . However, the same actions and effects can be realized for a design in which the metal thin plates are fixed to main body portion  48  by performing welding at a plurality of sites P 4  to P 9  on the outer periphery of metal thin plates  50  and performing caulking  53  at sites on the inner periphery of metal thin plates  50  as shown in FIG. 14; a design in which the metal thin plates are fixed to main body portion  48  by performing caulking  53  and  54  at the inner and outer peripheries of metal thin plates  50  as shown in FIG. 15; and a design in which the metal thin plates are fixed to the main body portion by performing caulking to sites on the outer periphery of the metal thin plates and performing welding to a plurality of sites on the inner periphery of the metal thin plates. 
     In other words, the means for fixing the plurality of metal thin plates  50  is not particularly restricted in the present invention. Rather, the means employed is acceptable provided there is fixing in place to a sufficient degree such that each of the metal thin plates  50  does not separate when the clutch torque is applied. It is also acceptable to fix metal thin plates  50  on their inner peripheral side or their outer peripheral side only. Similarly, the welding site, the number of welding spots, the caulking site, and the number of caulking spots for fixing metal thin plates  50  to main body portion  48  may be selected as appropriate. 
     In the second embodiment, the wall portion forming the end face of the driving rotor is formed by laminating together metal thin plates which are of equal thickness. However, it is also acceptable to form this wall portion by laminating together metal thin plates which have different thicknesses. When the driving rotor end face comes in contact with the armature plate, the armature plate contacts the end face of the driving rotor while sliding. Thus, the metal thin plate that comes in contact with the armature plate is scarcely abraded. According, by making the metal thin plate that comes in contact with the armature plate thicker that the other plate members, it is possible to prevent damage to the end face of the driving rotor by abrasion. In this case, the thickness of the metal thin plate that comes in contact with the armature plate is preferably 0.5 mm or more greater than the other metal thin plates. 
     In this embodiment, S12, S15, S17, or SPCC (SPCC-E supplied by Nippon Steel Corp. may also be used) was used for the metal thin plates, however, the material for the plates is not limited thereto. 
     Note that it is also acceptable to employ an electromagnetic clutch equipped with the armature plate disclosed in the first embodiment and the driving rotor disclosed in the second embodiment as modifications for the first and second embodiments. 
     The preceding embodiments described a scroll compressor, however the present invention is not limited thereto. It is also acceptable to employ other compressors such as a rotary compressor or a reciprocating compressor for example. 
     Further, these embodiments explained the case where the end face of the driving rotor and the armature plate were attached due to the magnetic force of the coil when the coil was excited by the impression of a voltage. However, the present invention also includes the case where the driving rotor end face and the armature plate are separated by the coil&#39;s magnetic force. 
     In the electromagnetic clutch of the present invention, the force generated when the armature plate is coupled with the end face of the driving rotor is reduced through the vibration of the individual plate members forming the armature plate. As a result, it is possible to reduce the noise of the contact between the armature plate and the driving rotor end face. 
     In addition, because the armature plate is less rigid as compared to conventional armature plates which consist of a thick plate formed as a unitary structure, the force generated when the armature plate and the end face of the driving rotor couple is reduced. The noise of the contact between the armature plate and the driving rotor end face can therefore be decreased. 
     By forming the plate members of the armature plate to have the same thickness in the above-described electromagnetic clutch, numerous plate members can be formed easily. As a result, the cost of the armature plate is decreased, and the cost of the electromagnetic clutch can be reduced. 
     Because the thickness of the plate member that comes in contact with the end face of the driving rotor from among the various plate members of said armature plate can be optionally varied, it is possible to realize an electromagnetic clutch according to a purpose of the electromagnetic clutch. 
     By making the plate member that comes in contact with the end face of the driving rotor thicker than the other plate members in this armature plate, it is possible to prevent damage to the armature plate from abrasion when contacting the end face of the driving rotor. 
     By forming each of the plate members to be roughly ring-shaped and made of metal, and welding at the outer or inner periphery of the plate member, it is possible to easily fix each of the plate members in place. 
     By performing a caulking operation on the end face of the plate member, the plate members can be fixed in place with confidence without carrying out a heat treatment. Thus, concerns about the effects of heat stress can be eliminated. 
     By providing the rotor in the present invention&#39;s electromagnetic clutch with the design described above, the force generated when the armature plate and the end face of the driving rotor couple is absorbed and by the vibration of the individual plate members forming the wall portion on the end face side of the driving rotor. Thus, the noise of the impact between the armature plate and the driving rotor can be reduced. 
     In addition, because the driving rotor end face is less rigid as compared to the conventional driving rotor end face which consists of a unitary structure, the force generated when the armature plate and the end face of the driving rotor couple is reduced. The noise generated when the armature plate contacts with the driving rotor end face can be decreased. 
     By forming the plate members of the rotor to have the same thickness, numerous plate members can be formed easily. As a result, the cost of the driving rotor is decreased, and the cost of the electromagnetic clutch can be reduced. 
     By making the plate member of the rotor that comes in contact with the armature plate thicker than the other plates, it is possible to prevent damage to the end face of the driving rotor from abrasion during contact with the armature plate. 
     By performing welding or caulking at the outer periphery and/or the inner periphery of the rotor plate members, it is possible to easily fix the various plate members to the main body portion of the driving rotor. 
     By employing an electromagnetic clutch provided with said armature plate and a rotor, a compressor with little noise can be realized.