JP2011002020A - Electromagnetic clutch, compressor, and manufacturing method for electromagnetic clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a contact area of an armature and a rotor without dramatically increasing the cost for increasing the attraction of the armature and the rotor.SOLUTION: Grooves 44, 45A, 45B of the armature 42 and the rotor 43 are formed by laser machining so that the widths of the grooves 44, 45A, 45B are set as little as possible at low cost within such a range that a short-circuit of magnetic flux does not occur. Thereby, the contact area of the armature 42 and the rotor 43 can be increased to increase the attraction towards each other. As a result, an allowance for torque transmission capacity of an electromagnetic clutch M is enhanced, and an increase of the torque of a scroll compressor 10 is achieved.

Description

The present invention relates to an electromagnetic clutch that is applied to, for example, a vehicle air conditioner and transmits power, a compressor including the electromagnetic clutch, and a method for manufacturing the electromagnetic clutch.

2. Description of the Related Art Conventionally, a compressor used in a vehicle air conditioner includes an electromagnetic clutch that is disposed between a drive source and transmits power.
The electromagnetic clutch can be selected by transmitting or not transmitting power by electromagnetic force. For example, the armature 2 is attracted to the rotor 3 by the magnetic force of the electromagnetic coil 1 as shown in FIG. And the rotor 3 are integrally coupled to transmit power (see, for example, Patent Document 1). In the illustrated configuration example, the radial width of the armature 2 is divided into two parts, and the radial width of the rotor 3 is divided into three parts, so that the contact surface (gap) 4 between the armature 2 and the rotor 3 is in the radial direction. Divided into four. In the following description, the contact surface 4 on the rotor 3 side is referred to as an armature contact surface 4a, and the armature 2 side is referred to as a rotor contact surface 4b.

Further, as shown in FIG. 7A, for example, the armature contact surface 4a of the rotor 3 is divided into three in the radial direction by a groove 5 having two groove widths a, and an inner ring 3a, a center ring 3b, An outer ring 3c is formed. The two grooves 5 are divided at a plurality of locations in the circumferential direction by a bridge 6 that connects the inner ring 3a, the center ring 3b, and the outer ring 3c.
Also in the radial direction of the armature 2, as shown in FIG. 7B, for example, the armature 2 is divided into an inner peripheral portion 2a and an outer peripheral portion 2b by a groove 7 having a groove width b. The groove 7 on the armature 2 side is also divided into a plurality of circumferential directions by a bridge 8 that connects the inner peripheral portion 2a and the outer peripheral portion 2b. The armature 2 in this case is composed of a plate punched from a plate material by punching.

JP 2003-314484 A

In the conventional electromagnetic clutch described above, when a sufficient attractive force cannot be secured between the armature 2 and the rotor 3, the margin of torque transmission capability is reduced. That is, there is a problem that a slip trouble occurs between the armature 2 and the rotor 3 when the margin of the torque transmission capability is reduced due to insufficient suction force.
As a countermeasure against the above-described trouble, it is known to process the surface of the rotor 3 to increase the friction coefficient. However, the surface processing of the rotor 3 is accompanied by an increase in the number of processing steps, and therefore an increase in manufacturing cost is inevitable.

  Therefore, it is conceivable to increase the contact area between the armature 2 and the rotor 3. For this, it is conceivable to increase the outer diameters of the armature 2 and the rotor 3, but this is not preferable because the outer diameter of the electromagnetic clutch increases and the size increases.

  The present invention has been made on the basis of such a technical problem, and it is possible to increase the contact area between the armature and the rotor without increasing the cost, and to increase the attractive force between the armature and the rotor. It is an object of the present invention to provide a method for manufacturing a clutch, a compressor, and an electromagnetic clutch.

The present invention made for this purpose is an electromagnetic clutch in which the armature is attracted to the contact surface of the rotor by the magnetic force of the electromagnetic coil, and the armature and the rotor are integrally coupled to transmit power. The ring-shaped grooves formed concentrically with the rotor are divided into a plurality of ring shapes in the radial direction, and the rotor contact surface of the armature is formed by the ring-shaped grooves formed concentrically with the armature. The groove is divided into a plurality of ring shapes in the radial direction, and at least a groove formed on the rotor contact surface of the armature is formed with a width of 0.5 to 1.5 mm by laser processing.
Thus, a groove having a width of 1.5 mm or less can be formed by forming the groove formed on the rotor contact surface of the armature by laser processing. And by setting the width of the groove to 0.5 to 1.5 mm, there is no short circuit of magnetic flux between the inner diameter side and the outer diameter side of the groove, and by reducing the width of the groove, The contact area with the armature can be increased.
It is more preferable that the width of the groove formed on the rotor contact surface of the armature is 0.8 to 1.2 mm.
Similarly, the grooves formed on the armature contact surface of the rotor can be formed by laser processing.

  For example, an outer groove and an inner groove are formed as grooves on the armature contact surface of the rotor, and an intermediate groove located between the outer groove and the inner groove is formed as a groove on the rotor contact surface of the armature. At this time, the first contact surface of the rotor and the armature on the inner peripheral side of the inner groove, the second contact surface of the rotor and the armature between the inner groove and the intermediate groove, and the rotor between the intermediate groove and the outer groove And a third contact surface of the armature, and a rotor and a fourth contact surface of the armature on the outer peripheral side of the outer groove. And each area of the second contact surface and the third contact surface is 11% or more with respect to the total area which is the area between the inner diameter side of the first contact surface and the outer diameter side of the fourth contact surface. Is preferable. Thereby, the area of the 2nd contact surface and the 3rd contact surface which are located in the both sides of an intermediate groove is securable more than fixed. Such a configuration is particularly effective when the areas of the second contact surface and the third contact surface are smaller than the areas of the first contact surface and the fourth contact surface, respectively. More preferably, the area of the second contact surface is 11% to 14% and the third contact surface is 12% to 15% with respect to the total area. The area of the third contact surface may be larger than the area of the second contact surface. The area of the fourth contact surface may be larger than the area of the third contact surface.

  Moreover, it is also preferable to set it as the structure where the area of the 4th contact surface located in an outer peripheral side is larger than each area of another contact surface (a 1st contact surface, a 2nd contact surface, a 3rd contact surface). This is because the contact area on the outer peripheral side of the rotor and the armature can be increased to improve the torque transmission force. Of course, it is not limited to this.

  The groove formed on the rotor contact surface of the armature can be formed with a smaller width than the groove formed on the armature contact surface of the rotor. Of course, it is also possible for both grooves to have the same width.

  The width of the groove formed on the rotor contact surface of the armature may be smaller than the total width of the groove formed on the armature contact surface of the rotor.

  The present invention relates to an electromagnetic clutch that attracts an armature to a contact surface of a rotor by a magnetic force of an electromagnetic coil and transmits power by integrally coupling the armature and the rotor. The armature contact surface of the rotor is formed concentrically with the rotor. The plurality of annular grooves are divided into a plurality of ring shapes in the radial direction, and the rotor contact surface of the armature is formed into a plurality of ring shapes in the radial direction by the annular grooves formed concentrically with the armature. The groove formed on at least the rotor contact surface of the armature is formed to have a width of 0.5 to 1.5 mm by laser processing, and the inner peripheral surface of the groove formed on the rotor contact surface of the armature is the armature It can also be characterized by having a higher hardness than the base material forming.

  The present invention may also be a compressor comprising the electromagnetic clutch according to any one of claims 1 to 6 which is mounted on a shaft portion of a compression mechanism and transmits power. .

  The present invention relates to a method of manufacturing an electromagnetic clutch that attracts an armature to a contact surface of a rotor by a magnetic force of an electromagnetic coil and transmits power by integrally coupling the armature and the rotor. The armature is provided on the rotor contact surface of the armature. And a concentric annular groove having a width of 0.5 to 1.5 mm by laser processing.

According to the present invention, by forming the groove formed on at least the rotor contact surface of the armature by laser processing, it is possible to form a groove having a width of 1.5 mm or less, which could not be realized by punching processing so far. And by reducing the width of the groove within the range where magnetic flux short-circuit does not occur on both sides of the groove, the pressure-bonding area between the rotor and the armature can be increased without much cost, and the attraction between the armature and the rotor The power can be increased.
In addition, the groove formed on the armature contact surface of the rotor can be similarly formed by laser processing to reduce the groove width. Similarly to the above, the pressure-bonding area between the rotor and the armature is greatly increased. The suction force between the armature and the rotor can be increased without increasing the cost.

It is a longitudinal section showing an example of composition of a scroll type compressor provided with an electromagnetic clutch in this embodiment. It is a perspective sectional view of an electromagnetic clutch. (A) is a top view of an armature, (b) is a top view of a rotor. It is an expanded sectional view which shows the crimping | compression-bonding part of an armature and a rotor. It is a figure which shows the result of the difference in the attraction | suction force of an armature and a rotor when changing the width | variety of the groove | channel formed in the armature and the rotor. It is a perspective sectional view of a conventional electromagnetic clutch, and an enlarged sectional view showing a crimping portion of an armature and a rotor. (A) is a top view of the conventional rotor, (b) is a top view of an armature.

Hereinafter, an embodiment of an electromagnetic clutch according to the present invention and a compressor including the electromagnetic clutch will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a configuration example of a scroll compressor provided with an electromagnetic clutch. The scroll compressor (compressor) 10 includes a front housing 11 and a rear housing 12, and includes a housing 13 in which the front housing 11 and the rear housing 12 are integrally fastened and fixed by bolts (not shown). ing.

Inside the front housing 11, a crankshaft (rotary shaft) 14 is rotatably supported around a rotation axis L via a main bearing (needle bearing) 15 and a sub-bearing (needle bearing) 16. One end side (the left side in FIG. 1) of the crankshaft 14 is a small diameter shaft portion 14a, and the small diameter shaft portion 14a penetrates the front housing 11 and protrudes to one end side. An electromagnetic clutch M is mounted on the protruding portion of the small-diameter shaft portion 14a, and between the pulley 18 provided rotatably on the outer peripheral surface of the small-diameter boss portion 11a on one end side of the front housing 11 via a bearing 17. The power is intermittent. Power is transmitted to the pulley 18 from an external drive source such as an engine (not shown) via a V-belt or the like.
Note that a mechanical seal (lip seal) 19 is provided between the main bearing 15 and the sub-bearing 16, thereby hermetically sealing the inside of the housing 13 and the atmosphere.

On the other hand, a large-diameter shaft portion 14 b is provided on the other end side (right side in FIG. 1) of the crankshaft 14, and the large-diameter shaft portion 14 b has a predetermined dimension from the rotation axis L of the crankshaft 14. An eccentric pin 14c is integrally provided in an eccentric state. The large-diameter shaft portion 14b and the small-diameter shaft portion 14a of the crankshaft 14 are rotatably supported by the front housing 11 via the main bearing 15 and the sub bearing 16, respectively.
Further, the orbiting scroll member 22 is connected to the eccentric pin 14c via the balance bush 20 and the drive bearing 21, and the orbiting scroll member 22 is driven to rotate by rotating the crankshaft 14. It has become.

The balance bush 20 is formed with a balance weight 20a for removing an unbalanced load generated when the orbiting scroll member 22 is orbitally driven. The balance weight 20a is orbited when the orbiting scroll member 22 is orbitally driven. Yes.
Inside the housing 13, a pair of fixed scroll portions 24 and a turning scroll member 22 constituting a scroll type compression mechanism 23 are incorporated.
The fixed scroll member 24 includes a fixed end plate 24a and a spiral wrap 24b erected from the fixed end plate 24a. On the other hand, the orbiting scroll member 22 includes the orbiting end plate 22a and the orbiting end plate. And a spiral wrap 22b erected from 22a.

  The fixed scroll member 24 and the orbiting scroll member 22 are assembled in a state where the centers of the fixed scroll member 24 and the orbiting scroll member 22 are separated by the orbiting radius and the spiral wraps 24b and 22b are engaged with each other with a phase difference of 180 degrees. As a result, a pair of compression chambers C defined by the end plates 24a and 22a and the spiral wraps 24b and 22b are formed symmetrically with respect to the scroll center between the scroll members 24 and 22. Will be.

The fixed scroll member 24 is fixed to the inner surface (bottom surface) of the rear housing 12 via a bolt 25. In the orbiting scroll member 22, an eccentric pin 14 c provided on one end side of the crankshaft 14 is fitted into a boss portion 26 provided on the back surface of the orbiting end plate 22 a via a balance bush 20 and a drive bearing 21. Thus, the crankshaft 14 is connected.
Further, the orbiting scroll member 22 has a thrust receiving surface 11b formed on the front housing 11 supported on the back surface of the orbiting end plate 22a, and the orbiting scroll member 22 is interposed between the thrust receiving surface 11b and the orbiting scroll member 22 on the back surface. The orbiting scroll member 22 is configured to be revolved and driven with respect to the fixed scroll member 24 while being prevented from rotating by the rotation-preventing pinning mechanism 27 mounted.

This rotation-preventing pin ring mechanism 27 includes a pin 27a and a ring 27b, and a pin hole 11c for standing the pin 27a on one of the back surface of the fixed end plate 22a of the orbiting scroll member 22 and the thrust receiving surface 11b is provided on the other side. Is provided with a ring hole 22c for fitting the ring 27b. In the present embodiment, the thrust receiving surface 11 b is provided with a pin hole 11 c for standing the pin 27 a, and the orbiting scroll member 22 is provided with a ring hole 22 c for fitting the ring 27 b.
The pin holes 11c and the ring holes 22c are provided at a plurality of locations in the circumferential direction, generally 3 to 4 locations (4 locations in the present embodiment).

Further, a discharge port 24c for discharging compressed refrigerant gas is opened at the center of the fixed end plate 24a of the fixed scroll member 24. The discharge port 24c is connected to the fixed end plate 24a via a retainer 28. A discharge reed valve (not shown) is provided.
Further, a seal member (not shown) such as an O-ring is installed on the back surface of the fixed end plate 24 a of the fixed scroll member 24 so as to be in close contact with the inner surface of the rear housing 12. A discharge chamber 29 partitioned from the internal space (sealed space) is formed. Thereby, the internal space of the housing 13 excluding the discharge chamber 29 functions as the suction chamber 30.

Refrigerant gas returning from the refrigeration cycle is sucked into the suction chamber 30 via a suction port (not shown) provided in the front housing 11, and the fixed scroll member 24 and the orbiting scroll member are passed through the suction chamber 30. The refrigerant gas is sucked into the compression chamber C formed between the two.
A sealing member 31 such as an O-ring is installed on the joint surface between the front housing 11 and the rear housing 12, and the suction chamber 30 in the housing 13 is hermetically sealed from the atmosphere.

The scroll compressor 10 configured as described above operates as follows.
The rotational driving force transmitted from the external drive source to the pulley 18 is transmitted to the crankshaft 14 via the electromagnetic clutch M, and the crankshaft 14 is rotated. Then, the orbiting scroll member 22 connected to the eccentric pin 14c of the crankshaft 14 via the balance bush 20 and the drive bearing 21 is prevented from rotating by the rotation preventing pin ring mechanism 27 while being rotated against the fixed scroll member 24. Revolved and driven.

  The revolving orbiting drive of the orbiting scroll member 22 causes the refrigerant gas in the suction chamber 30 to be sucked into the compression chamber C formed at the outermost side in the radial direction. After the compression chamber C is closed by suction at a predetermined swivel angle position, the compression chamber C is moved to the center side while the volume is reduced in the circumferential direction and the lap height direction. During this time, the refrigerant gas is compressed, and when the compression chamber C reaches a position communicating with the discharge port 24c, the discharge reed valve is pushed open and the compressed gas is discharged into the discharge chamber 29. It is discharged out of the compressor through a discharge port (not shown) provided in the rear housing 12.

  The scroll compressor 10 described above includes an electromagnetic clutch M that is mounted on the crankshaft 14 of the compression mechanism and transmits power. The electromagnetic clutch M attracts the magnetic armature 42 to the contact surface of the rotor 43 by the magnetic force of the electromagnetic coil 41, and transmits the power by integrally coupling the armature 42 and the rotor 43.

In the electromagnetic clutch M of the present embodiment, for example, as shown in FIGS. 2 and 3A, the radial direction of the armature 42 is divided into two by a groove (intermediate groove) 44 having a width b, and an inner ring 42a, An outer peripheral ring 42b is formed. The groove 44 is divided at a plurality of locations in the circumferential direction by a bridge 50 that connects the inner ring 42a and the outer ring 42b. The grooves 44 divided by the bridge 50 each form an arc having the same width with the groove width being b.
Further, the electromagnetic clutch M of the present embodiment includes two grooves (inner circumferential grooves) 45A and grooves (outer circumferential grooves) in which the radial direction of the rotor 43 has a width a as shown in FIGS. 2 and 3B, for example. 3) divided by 45B to form an inner ring 43a, a center ring 43b, and an outer ring 43c. The two grooves 45A and 45B are divided at a plurality of locations in the circumferential direction by bridges 51A and 51B connecting the inner ring 43a, the center ring 43b, and the outer ring 43c. The grooves 45A and 45B divided by the bridges 51A and 51B each form an arc having the same width with the groove width being a.

As shown in FIG. 4, the grooves 44, 45 </ b> A and 45 </ b> B formed in this way allow the rotor contact surface 46 a of the armature 42 and the armature contact surface 46 b of the rotor 43 to be connected to the inner peripheral ring 43 a of the rotor 43. An annular first contact surface A1 facing the inner ring 42a, an inner second ring A2 of the armature 42 facing the center ring 43b of the rotor 43, and an outer ring 42b of the armature 42 are the rotor. The annular contact surface A3 facing the central ring 43b of 43 and the outer ring 43c of the rotor 43 generate a suction force with the annular fourth contact surface A4 facing the outer ring 42b of the armature 42.
Here, the first contact surface A1, the second contact surface A2, the third contact surface A3, and the fourth contact surface A4 are configured so that the areas of the annular areas are substantially equal to each other so that the suction force is equalized. It is preferable to form the grooves 44, 45A, 45B. Further, in order to increase the force against the rotational torque when the armature 42 and the rotor 43 are attracted to each other, of the first contact surface A1, the second contact surface A2, the third contact surface A3, and the fourth contact surface A4, The area of the fourth contact surface A4 on the outer periphery may be maximized.

In the present embodiment, among the first contact surface A1, the second contact surface A2, the third contact surface A3, and the fourth contact surface A4, the second contact surface A2 and the third contact located on both sides of the groove 44 of the armature 42. The area of one or both of the surfaces A3 tends to be the smallest. Therefore, the area of the second contact surface A2 and the third contact surface A3 is 11% or more with respect to the total area A0 between the inner diameter side of the first contact surface A1 and the outer diameter side of the fourth contact surface A4. It is preferable to form so as to occupy. More preferably, the area of the second contact surface A2 is 11% to 14% with respect to the total area A0, and the third contact surface A3 is 12% to 15% with respect to the total area A0.
In this way, the area of the second contact surface A2 or the third contact surface A3 having the smallest area among the contact surface A1, the second contact surface A2, the third contact surface A3, and the fourth contact surface A4 is more than a certain value. By ensuring, the contact area in 2nd contact surface A2 or 3rd contact surface A3 can be ensured as much as possible.

The grooves 44, 45A and 45B are formed by laser processing. In laser processing, the plate material is cut (fused) into a predetermined shape by moving the laser beam, the armature 42, and the rotor 43 relative to each other while irradiating the plate material forming the armature 42 and the rotor 43 with laser light. Thus, the grooves 44, 45A and 45B are formed.
Of the grooves 44, 45A and 45B formed in this way, at least the groove 44 located between the second contact surface A2 and the third contact surface A3 having the smallest area has a width b of 0, respectively. 0.5 to 1.5 mm is preferable, and a more preferable range is 0.8 to 1.2 mm. When the width of the groove 44 exceeds the above range, the effect of increasing the contact area between the armature 42 and the rotor 43 due to the narrowing of the groove 44 is small. When the width of the groove 44 is below the above range, the inner diameter side and the outer diameter of the groove 44 are reduced. A short circuit of magnetic flux occurs between the armature 42 and the rotor 43, and the attractive force between the armature 42 and the rotor 43 decreases.
The same applies to the grooves 45A and 45B, but in this embodiment, the width b of the groove 44 is set smaller than the width a of the grooves 45A and 45B. Of course, the width b of the groove 44 can be made equal to the width a of the grooves 45A and 45B. Further, the width b of the groove 44 can be set smaller than the sum of the widths a of the grooves 45A and 45B.

  In this way, by forming the grooves 44, 45A, 45B by laser processing, the widths a, b of the grooves 44, 45A, 45B are set as low as possible within a range that does not cause a short circuit of magnetic flux at low cost. be able to. Thereby, the pressure-bonding area between the armature 42 and the rotor 43 can be increased without increasing the size of the armature 42 and the rotor 43, and the mutual suction force can be increased. As a result, the margin of torque transmission capability in the electromagnetic clutch M can be increased, and the torque of the scroll compressor 10 can be increased.

  Further, by forming the grooves 44, 45A, 45B by laser processing, the inner peripheral surfaces of the grooves 44, 45A, 45B are hardened by heat input by the laser beam, and the hardness of the base material of the armature 42 and the rotor 43 is increased. It is larger than the hardness. As a result, the strength of the grooves 44, 45A, 45B can be increased.

Here, in the electromagnetic clutch M provided with the armature 42 and the rotor 43, the difference in the attractive force between the armature 42 and the rotor 43 when the widths of the grooves 44, 45A, 45B were changed was examined. Indicates.
First, the armature 42 and the rotor 43 are made of a steel material such as carbon steel, and have an annular shape with an outer diameter of 110 mm and an inner diameter of 65 mm.

  Then, as shown in Table 1, the width b of the groove 44 of the armature 42 is changed to 0.5, 0.8, 1.0, 1.2, 1.5, 2.2 (current) mm, At this time, the ratio of the attractive force between the armature 42 and the rotor 43 when a magnetic field was generated by the electromagnetic coil 41 under the same conditions was obtained by simulation using an electronic computer.

The result is shown in FIG.
As shown in FIG. 5, it was confirmed that the suction force between the armature 42 and the rotor 43 is greatly improved by making the groove 44 smaller than the current width b = 2.2 mm. It was also confirmed that the suction force between the armature 42 and the rotor 43 slightly decreased when the width b of the groove 44 was 0.5 mm.

In the above embodiment, the configuration of the scroll compressor 10 has been described. However, the configuration of other parts other than the configuration related to the main part of the present invention is not limited at all. The same applies to the electromagnetic clutch M.
In addition to this, as long as it does not depart from the gist of the present invention, the configuration described in the above embodiment can be selected or changed to another configuration as appropriate.

  DESCRIPTION OF SYMBOLS 10 ... Scroll type compressor (compressor), 41 ... Electromagnetic coil, 42 ... Armature, 42a ... Inner ring, 42b ... Outer ring, 43 ... Rotor, 43a ... Inner ring, 43b ... Central ring, 43c ... Outer ring 44 ... groove (intermediate groove), 45A ... groove (inner circumferential groove), 45B ... groove (outer circumferential groove), 46a ... rotor contact surface, 46b ... armature contact surface, A1 ... first contact surface, A2 ... second contact Surface, A3 ... third contact surface, A4 ... fourth contact surface, M ... electromagnetic clutch

Claims (10)

In the electromagnetic clutch that attracts the armature to the contact surface of the rotor by the magnetic force of the electromagnetic coil and transmits the power by integrally coupling the armature and the rotor,
The armature contact surface of the rotor is divided into a plurality of ring shapes in the radial direction by a plurality of annular grooves formed concentrically with the rotor,
The rotor contact surface of the armature is divided into a plurality of ring shapes in the radial direction by an annular groove formed concentrically with the armature,
An electromagnetic clutch characterized in that at least the groove formed on the rotor contact surface of the armature is formed with a width of 0.5 to 1.5 mm by laser processing.   The electromagnetic clutch according to claim 1, wherein a width of the groove formed on the rotor contact surface of the armature is 0.8 to 1.2 mm. An outer groove and an inner groove are formed as the groove on the armature contact surface of the rotor,
An intermediate groove located between the outer groove and the inner groove is formed as the groove on the rotor contact surface of the armature,
The first contact surface of the rotor and the armature on the inner peripheral side of the inner groove, the second contact surface of the rotor and the armature between the inner groove and the intermediate groove, the intermediate groove and the outer surface When the rotor and the third contact surface of the armature between the grooves and the fourth contact surface of the rotor and the armature on the outer peripheral side than the outer groove, the inner diameter side of the first contact surface and the fourth contact surface 3. The electromagnetic clutch according to claim 1, wherein an area of each of the second contact surface and the third contact surface is 11% or more with respect to an area between the outer diameter side of the surface.   4. The electromagnetic clutch according to claim 3, wherein areas of the second contact surface and the third contact surface are smaller than areas of the first contact surface and the fourth contact surface, respectively.   5. The electromagnetic clutch according to claim 3, wherein an area of the fourth contact surface is larger than areas of the other first contact surface, the second contact surface, and the third contact surface. 6. .   The width of the groove formed on the rotor contact surface of the armature is smaller than the width of the groove formed on the armature contact surface of the rotor. The electromagnetic clutch according to one item.   The width of the groove formed on the rotor contact surface of the armature is smaller than the total width of the groove formed on the armature contact surface of the rotor. The electromagnetic clutch according to any one of 5. In the electromagnetic clutch that attracts the armature to the contact surface of the rotor by the magnetic force of the electromagnetic coil and transmits the power by integrally coupling the armature and the rotor,
The armature contact surface of the rotor is divided into a plurality of ring shapes in the radial direction by a plurality of annular grooves formed concentrically with the rotor,
The rotor contact surface of the armature is divided into a plurality of ring shapes in the radial direction by an annular groove formed concentrically with the armature,
At least the groove formed on the rotor contact surface of the armature is formed with a width of 0.5 to 1.5 mm by laser processing, and the inner peripheral surface of the groove formed on the rotor contact surface of the armature is An electromagnetic clutch characterized by having a hardness higher than that of the base material forming the armature.   A compressor comprising the electromagnetic clutch according to any one of claims 1 to 8, which is mounted on a shaft portion of a compression mechanism and transmits power. A method of manufacturing an electromagnetic clutch that attracts an armature to a contact surface of a rotor by a magnetic force of an electromagnetic coil, and transmits power by integrally coupling the armature and the rotor,
A method for manufacturing an electromagnetic clutch, comprising: forming at least a concentric annular groove on the rotor contact surface of the armature with a width of 0.5 to 1.5 mm by laser processing.

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