WO2019132222A1

WO2019132222A1 - Electronic clutch and compressor including same

Info

Publication number: WO2019132222A1
Application number: PCT/KR2018/013332
Authority: WO
Inventors: 김승길; 김민환; 정석제
Original assignee: 한온시스템 주식회사
Priority date: 2017-02-22
Filing date: 2018-11-06
Publication date: 2019-07-04
Also published as: KR20180097125A; KR102460908B1

Abstract

The present invention relates to an electronic clutch and a compressor including the same, the clutch comprising: a pulley; a disc hub assembly fastened to a rotary shaft of the compressor, and selectively coming in contact with and being spaced from the pulley; and a field coil assembly for bringing the pulley and the disc hub assembly in contact with each other, wherein the pulley includes a plurality of inner slots, a plurality of outer slots, a plurality of inner bridges, and a plurality of outer bridges, and the plurality of outer bridges can be formed such that, in a rotational radial direction, a portion thereof is overlapped with the plurality of inner bridges and the other portion thereof is not overlapped with the same. Therefore, suction force between the pulley and the disc hub assembly is included in a predetermined range, the rigidity of the pulley is included in a predetermined range, and noise and vibration, generated when the pulley and the disc hub assembly come in contact with each other, can be included in a predetermined range.

Description

ELECTRIC CLUTCH AND COMPRESSOR CONTAINING THE SAME

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic clutch and a compressor including the electromagnetic clutch. More particularly, the present invention relates to an electromagnetic clutch and a compressor including the electromagnetic clutch, which can magnetize and demagnetize the drive clutch, .

Generally, an automobile is provided with an air conditioner (A / C) for cooling and heating the room. Such an air conditioner includes a compressor that compresses gaseous low-temperature and high-pressure gaseous refrigerant introduced from an evaporator into gaseous refrigerant of high temperature and high pressure and sends it to a condenser.

The compressor includes a reciprocating type compressing the refrigerant according to the reciprocating movement of the piston, and a rotary type compressing while rotating. In the reciprocating type, there are a crank type which uses a crank according to a transmission method of a drive source and a crank type which transmits the same to a plurality of pistons, a swash plate type which transmits a swash plate with a swash plate type rotary shaft, a vane rotary type using a rotary shaft, There are scrolling expressions using orbiting scroll and fixed scroll.

Such a compressor typically includes a rotary shaft for transmitting a rotational force to a compressor means for compressing a refrigerant and includes an electromagnetic clutch for selectively connecting and disconnecting a rotary shaft from a drive source (for example, an engine) of the compressor, As shown in FIG.

1 is a sectional view showing a compressor including an electromagnetic clutch. Referring to FIG. 1, the compressor includes a casing 1, a compression mechanism provided inside the casing 1 for compressing refrigerant, A rotary shaft 3 for transmitting a rotational force from a driving source (for example, an engine) (not shown) provided outside the casing 1 to the compression mechanism 2, And an electromagnetic clutch (4) for selectively connecting and disconnecting the rotary shaft (3).

The electromagnetic clutch 4 includes a pulley 5 that is rotated by receiving power from the driving source (not shown), a disc hub assembly (not shown) coupled to the rotating shaft 3 and selectively in contact with and spaced from the pulley 5 A field coil assembly 7 which is magnetized when power is applied and brought into contact with the pulley 5 and the disc hub assembly 6 and a field coil assembly 7, (Not shown) that separates the pulley 5 and the disc hub assembly 6 from each other.

The pulley 5 is formed in a substantially annular shape and a drive belt (not shown) provided with a drive belt (not shown) for transmitting driving force from the drive source (not shown) to the pulley 5 is provided on the outer peripheral surface of the pulley 5 And a bearing 8 for rotatably supporting the pulley 5 is interposed between the inner circumferential surface of the pulley 5 and the outer surface of the casing 1. [ A friction surface 54 is formed on one side surface of the pulley 5 so as to contact the disk 64 of the disk hub assembly 6, A field coil assembly receiving groove 55 into which the field coil assembly 7 is inserted is formed.

The disc hub assembly 6 includes a hub 62 coupled to the rotating shaft 3 and a disc 64 extending from the hub 62 and selectively contacting and spacing the pulley 5.

The field coil assembly 7 includes a coil housing 72 and a coil 74 housed in the coil housing 72 and generating an electromagnetic force upon power application.

The spacing means (not shown) is formed of an elastic member that forces the disc hub assembly 6 in a direction away from the pulley 5.

The compressor according to this configuration operates as follows.

That is, the pulley 5 receives the driving force from the driving source (not shown) and is rotated.

In this state, when power is applied to the coil 74, the disk hub assembly 6 is moved toward the pulley 5 by the attraction force by the magnetic induction of the coil 74, . The disk hub assembly 6 and the pulley 5 are coupled so that the power of the drive source (not shown) is transmitted to the rotary shaft 3 through the pulley 5 and the disk hub assembly 6 do. The rotary shaft (3) operates the compression mechanism (2) with the transmitted power to compress the refrigerant.

On the other hand, when the power supply to the coil 74 is stopped, the suction force by the magnetic induction of the coil 74 is not generated, and the disk hub assembly 6 is rotated by the spacing means Is moved away from the pulley (5) and separated from the pulley (5). That is, power transmission from the driving source (not shown) to the rotating shaft 3 is interrupted. Then, the operation of the compression mechanism (2) is stopped, and the refrigerant compression is stopped.

Wherein the pulley 5 has its friction plate 53 attached to the friction plate 53 having the friction surface 54 so that the attracted magnetic flux of the field coil assembly 7 is effectively transferred to the disk hub assembly 6. [ Wherein the

slots

532 and 535 extend through the

slots

532 and 535 to increase the attraction flux of the field coil assembly 7 transmitted to the

disk hub assembly

6, 5 and the disk hub assembly 6 while ensuring the stiffness of the pulley 5 to a predetermined level. 2 is a front view showing a pulley 5 in the electromagnetic clutch 4 according to an embodiment of the related art. Referring to FIG. 2, a pulley 5 according to a conventional example includes: And the

slots

532 and 535 penetrate the friction plate 53 and the

slots

532 and 535 are spaced apart from each other by a predetermined first distance from the center of rotation of the friction plate 53, A plurality of inner slots 532 formed along the rotation direction of the friction plate 53 and a rotation of the friction plate 53 at a position spaced from the rotation center of the friction plate 53 by a second distance that is longer than the first distance, And a plurality of outer slots 535 formed along the direction. The friction plate 53 includes an inner circumferential portion 531 positioned radially inwardly of the friction plate 53 with respect to the inner slot 532 and an inner circumferential portion 531 located on the outer circumferential surface of the friction plate 53, An intermediate portion 534 positioned between the inner slot 532 and the outer slot 535 and a middle portion 534 interposed between the inner slots 532 and the inner slot 533, A plurality of inner bridges 533 connecting the main portion 531 and the intermediate portion 534 and a plurality of inner bridges 533 interposed between the plurality of outer slots 535 and connecting the intermediate portion 534 and the outer peripheral portion 537, And a plurality of outer bridges 536 for connecting the outer bridges. Here, the inner slot 532 and the outer slot 535 are formed to overlap with each other in the radial direction of rotation of the friction plate 53. That is, any one of the inner slots 532 of the plurality of inner slots 532 overlaps with one of the plurality of outer slots 535 in the radial direction of rotation of the

friction plate

53, 535 are formed to overlap with one of the plurality of inner slots 532 and the friction plate 53 in the radial direction of rotation. Similarly, the inner bridge 533 and the outer bridge 536 are formed to overlap with each other in the radial direction of rotation of the friction plate 53. That is, any of the plurality of inner bridges 533 is overlapped with one of the plurality of outer bridges 536 in the radial direction of rotation of the friction plate 53, and the plurality of outer bridges 536 536 are formed so as to overlap with one of the plurality of inner bridges 533 and the friction plate 53 in the radial direction of rotation. However, in this case, resonance is generated, and noise and vibration are deteriorated. Specifically, when the pulley 5 and the disk hub assembly 6 are in contact with each other, a squeal noise and accompanying vibration are generated. Here, the skill noise may be referred to as chirp noise or cue noise, and a stick slip may be generated during sliding contact between the pulley 5 and the disc hub assembly 6, And the noise caused by the vibration caused by the stick slip is released when it is grown and accumulated and exceeds its accumulation limit. Here, the growth of vibration is mainly caused by resonance. In the conventional pulley 5 shown in FIG. 2, resonance is easily generated as shown in FIG. 6, so that skill noise and accompanying vibration are deteriorated.

On the other hand, a pulley 5 for improving noise and vibration due to contact between the pulley 5 and the disk hub assembly 6 has been disclosed. 3 is a front view showing the pulley 5 in the electromagnetic clutch 4 according to another embodiment of the present invention. Referring to FIG. 3, a pulley 5 according to another embodiment of the present invention includes: The inner bridge 533 and the outer bridge 536 are formed so as not to overlap with each other in the radial direction of rotation of the friction plate 53. [ That is, any one of the inner bridges 533 of the plurality of inner bridges 533 is not overlapped with any of the plurality of outer bridges 536 in the radial direction of rotation of the friction plate 53, Any of the outer bridges 536 of the bridge 536 is formed so as not to overlap with any of the plurality of inner bridges 533 in the radial direction of rotation of the friction plate 53. In this case, as shown in Fig. 6, no resonance occurs and the vibration due to the stick slip is not grown, so that the skill noise and the vibration accompanying it are improved. In this case, however, the rigidity of the pulley 5 is weakened as shown in Fig. That is, in this case, the suction force between the pulley 5 and the disk hub assembly 6 is included within a predetermined range, and the noise generated when the pulley 5 and the disk hub assembly 6 are in contact with each other Is included in the predetermined range, but the stiffness of the pulley 5 falls short of the predetermined range.

6 is a graph comparing the electromagnetic clutch performance, the pulley rigidity and the resonant frequency according to the pulleys shown in Figs. 2 to 5, wherein the pulleys and the disks, which are numerical values capable of comparing the electromagnetic clutch performance, And the maximum stress and resonance frequency given to the bridge of the pulley, which is a value that can compare the suction force between the hub assembly and the stiffness of the pulley. The suction force between the pulley and the disc hub assembly is a relative value based on the pulley of FIG. 2. The larger the percentage, the stronger the attracting force between the pulley and the disc hub assembly than the pulley of FIG. 2 and the better the electromagnetic clutch performance. The maximum stress applied to the bridge of the pulley is a relative value based on the maximum stress applied to the inner bridge of the pulley of Fig. 2, and the smaller the percentage, the more the maximum stress applied to the bridge of the pulley than the pulley of Fig. It is small and has a strong pulley rigidity.

Therefore, in the conventional electromagnetic clutch 4 and the compressor including the electromagnetic clutch 4, the suction force between the pulley 5 and the disk hub assembly 6 is increased, the rigidity of the pulley 5 is secured, and the pulley 5 and the disk hub assembly 6 The noise and the vibration reduction can not be achieved at the same time.

Accordingly, it is an object of the present invention to provide an electromagnetic clutch capable of simultaneously increasing suction force between a pulley and a disk hub assembly, ensuring rigidity of the pulley, and noise and vibration reduction occurring when the pulley and disk hub assembly are in contact, and a compressor including the same For that purpose.

In order to achieve the above object, the present invention provides a pulley which is rotated by receiving power from a driving source; A disk hub assembly coupled to a rotary shaft of the compressor and selectively in contact with and spaced from the pulley; And a field coil assembly magnetized upon application of power to contact the pulley and the disc hub assembly, the pulley comprising a plurality of inner slots for transmitting a suction flux of the field coil assembly to the disc hub assembly And a plurality of outer slots; A plurality of inner bridges interposed between the inner slots; And a plurality of outer bridges interposed between the plurality of inner bridges, wherein the plurality of outer bridges are partially overlapped with the plurality of inner bridges in a radial direction of rotation, Lt; / RTI >

Wherein the pulley includes a friction plate capable of being in contact with the disk hub assembly, the friction plate comprising: a plurality of inner slots formed along a rotational direction of the friction plate at a position spaced apart from a center of rotation of the friction plate by a predetermined first distance; The plurality of outer slots being formed along a rotational direction of the friction plate at a position spaced apart from the center of rotation of the friction plate by a second distance that is longer than the first distance; An inner circumference positioned radially inwardly of the friction plate with respect to the inner slot; An outer circumferential portion positioned radially outward of the friction plate with respect to the outer slot; An intermediate portion positioned between the inner slot and the outer slot; The plurality of inner bridges interposed between the plurality of inner slots and connecting the inner peripheral portion and the intermediate portion; And the plurality of outer bridges interposed between the plurality of outer slots and connecting the intermediate portion and the outer peripheral portion. The plurality of outer bridges may include an overlapping outer bridge overlapping with one of the plurality of inner bridges in a rotating radial direction; And a non-overlapping outer bridge that does not overlap with any of the plurality of inner bridges in the radial direction of rotation.

Wherein the plurality of inner slots and the plurality of inner bridges are each formed of n, and the n inner slots and the n inner bridges are alternately formed along the rotational direction of the friction plate, And the n inner bridges may be formed at regular intervals along the rotational direction of the friction plate. Wherein the plurality of outer slots and the plurality of outer bridges are formed in m different from the n slots, the m outer slots and the m outer bridges are alternately formed along the rotational direction of the friction plate, Slots may be formed at regular intervals along the rotational direction of the friction plate, and the m inner bridges may be formed at regular intervals along the rotational direction of the friction plate.

The overlapping outer bridge may be formed of two.

The two superposed outer bridges may be formed at positions symmetrical to each other with respect to the center of rotation of the friction plate.

Meanwhile, according to an embodiment, the inner slots and the plurality of inner bridges are each formed of six, and the outer slots and the plurality of outer bridges may be respectively formed of eight.

The plurality of inner slots include a first inner slot, a second inner slot, a third inner slot, a fourth inner slot, a fifth inner slot, and a sixth inner slot sequentially formed along the rotational direction of the friction plate can do. The plurality of inner bridges may include a first inner bridge interposed between the first inner slot and the second inner slot, a second inner bridge interposed between the second inner slot and the third inner slot, A third inner bridge interposed between the fourth inner slot and the fourth inner slot, a fourth inner bridge interposed between the fourth inner slot and the fifth inner slot, and a second inner bridge interposed between the fifth inner slot and the sixth inner slot, And a sixth inner bridge interposed between the sixth inner slot and the first inner slot. The plurality of outer slots may include a first outer slot, a second outer slot, a third outer slot, a fourth outer slot, a fifth outer slot, a sixth outer slot, and a seventh outer slot sequentially formed along the rotational direction of the friction plate. Slot and an eighth outer slot. The plurality of outer bridges may include a first outer bridge interposed between the first outer slot and the second outer slot, a second outer bridge interposed between the second outer slot and the third outer slot, A third outer bridge interposed between the fourth outer slot and the fourth outer slot, a fourth outer bridge interposed between the fourth outer slot and the fifth outer slot, and a third outer bridge interposed between the fifth outer slot and the sixth outer slot, A sixth outer bridge interposed between the sixth outer slot and the seventh outer slot, a seventh outer bridge interposed between the seventh outer slot and the eighth outer slot, and a seventh outer bridge interposed between the seventh outer slot and the eighth outer slot, And an eighth outer bridge interposed between the slot and the first outer slot.

The first inner bridge and the first outer bridge are overlapped with each other in the radial direction of rotation of the friction plate, the fourth inner bridge and the fifth outer bridge are overlapped with each other in the radial direction of rotation of the friction plate, The inner bridge and the fourth inner bridge are symmetrical to each other with respect to the rotation center of the friction plate, and the first outer bridge and the fifth outer bridge are formed symmetrically with respect to the rotation center of the friction plate.

The second outer bridge is overlapped with each other in the radial direction of rotation of the second inner slot and the friction plate and the third outer bridge overlaps with each other in the radial direction of rotation of the third inner slot and the friction plate, 4 outer bridges overlap each other in the radial direction of rotation of the fourth inner slot and the friction plate, the sixth outer bridge overlaps with each other in the radial direction of rotation of the fifth inner slot and the friction plate, and the seventh outer bridge The sixth inner slot and the friction plate overlap each other in the radial direction of rotation, and the eighth outer bridge may be formed to overlap with each other in the radial direction of rotation of the first inner slot and the friction plate.

The second inner bridge is overlapped with each other in the radial direction of rotation of the third outer slot and the friction plate and the third inner bridge overlaps with each other in the radial direction of rotation of the fourth outer slot and the friction plate, 5 inner bridges are overlapped with each other in the radial direction of rotation of the seventh outer slot and the friction plate and the sixth inner bridge is formed to overlap with each other in the radial direction of rotation of the eighth outer slot and the friction plate.

According to another embodiment, the inner slots and the plurality of inner bridges are each formed of six, and the outer slots and the plurality of outer bridges may each be formed of four.

The plurality of inner slots include a first inner slot, a second inner slot, a third inner slot, a fourth inner slot, a fifth inner slot, and a sixth inner slot sequentially formed along the rotational direction of the friction plate Wherein the plurality of inner bridges includes a first inner bridge interposed between the first inner slot and the second inner slot, a second inner bridge interposed between the second inner slot and the third inner slot, A third inner bridge interposed between the third inner slot and the fourth inner slot, a fourth inner bridge interposed between the fourth inner slot and the fifth inner slot, and a fourth inner bridge interposed between the fifth inner slot and the sixth inner slot, And a sixth inner bridge interposed between the sixth inner slot and the first inner slot, wherein the plurality of outer slots are arranged in a circumferential direction along the rotational direction of the friction plate, A first outer slot, a second outer slot, a third outer slot, and a fourth outer slot, the plurality of outer bridges including a first outer slot, a second outer slot, An outer bridge, a second outer bridge interposed between the second outer slot and the third outer slot, a third outer bridge interposed between the third outer slot and the fourth outer slot, and a third outer bridge interposed between the fourth outer slot and the third outer slot, And a fourth outer bridge interposed between the fifth outer slots.

The first inner bridge and the first outer bridge overlap each other in the radial direction of rotation of the friction plate, the fourth inner bridge and the third outer bridge overlap each other in the radial direction of rotation of the friction plate, The inner bridge and the fourth inner bridge are symmetrical to each other with respect to the center of rotation of the friction plate, and the first outer bridge and the third outer bridge are formed symmetrically with respect to the center of rotation of the friction plate.

The second outer bridge may be overlapped with the third inner slot in the radial direction of rotation of the third inner slot and the friction plate and the fourth outer bridge may be formed to overlap with each other in the radial direction of rotation of the sixth inner slot and the friction plate. have.

The second inner bridge is overlapped with each other in the radial direction of rotation of the second outer slot and the friction plate and the third inner bridge overlaps with each other in the radial direction of rotation of the third outer slot and the friction plate, 5 inner bridges are overlapped with each other in the radial direction of rotation of the fourth outer slot and the friction plate and the sixth inner bridge overlaps with each other in the radial direction of rotation of the first outer slot and the friction plate.

The pulleys may be formed such that the sum of the widths of the plurality of outer bridges is less than or equal to the sum of the widths of the plurality of inner bridges.

Further, the present invention provides a refrigerating machine comprising: a compression mechanism provided in the casing and compressing refrigerant; A rotating shaft for transmitting rotational force from a driving source provided outside the casing to the compressor; And a power transmitting mechanism for selectively connecting and disconnecting the driving source and the rotating shaft, wherein the power transmitting mechanism includes the electromagnetic clutch.

An electromagnetic clutch and a compressor including the same according to the present invention include: a pulley that receives power from a drive source and is rotated; A disk hub assembly coupled to a rotary shaft of the compressor and selectively in contact with and spaced from the pulley; And a field coil assembly magnetized upon application of power to contact the pulley and the disc hub assembly, the pulley having a plurality of inner slots for transmitting a suction flux of the field coil assembly to the disc hub assembly, Outer slot; A plurality of inner bridges interposed between the inner slots; And a plurality of outer bridges interposed between the plurality of outer slots, wherein the plurality of outer bridges partially overlap with the plurality of inner bridges and are formed so as not to overlap with each other. Thereby, the suction force between the pulley and the disk hub assembly is included in a predetermined range, the rigidity of the pulley is included in a predetermined range, and the noise and vibration generated when the pulley and the disk hub assembly are in contact with each other And may be included in a predetermined range.

1 is a sectional view showing a compressor including an electromagnetic clutch,

2 is a front view showing a pulley in an electromagnetic clutch according to a conventional example,

3 is a front view showing a pulley in an electromagnetic clutch according to another conventional example,

4 is a front view showing a pulley in an electromagnetic clutch according to an embodiment of the present invention;

5 is a front view showing a pulley in an electromagnetic clutch according to another embodiment of the present invention;

FIG. 6 is a graph comparing the electromagnetic clutch performance, the pulley stiffness, and the resonant frequency according to the pulleys of FIGS. 2 to 5, comparing the attraction between the pulley and the disk hub assembly, and the stiffness of the pulley, The maximum stress and the resonance frequency given to the bridge of the pulley, which is a numerical value.

Hereinafter, an electromagnetic clutch and a compressor including the same according to the present invention will be described in detail with reference to the accompanying drawings.

4 is a front view showing a pulley in an electromagnetic clutch according to an embodiment of the present invention. FIG. 6 is a graph comparing the electromagnetic clutch performance, the pulley stiffness, and the resonant frequency according to the pulley of FIG. 4 to that of a conventional pulley. The suction force between the pulley and the disk hub assembly, The maximum stress and the resonance frequency given to the bridge of the pulley which is a comparable value. 6, the suction force between the pulley and the hub assembly is a relative value based on the pulley of FIG. 2, and the larger the percentage is, the more attractive the pulling force between the pulley and the hub assembly than the pulley of FIG. 2 And the electromagnetic clutch performance is excellent. The maximum stress applied to the bridge of the pulley is a relative value based on the maximum stress applied to the inner bridge of the pulley of Fig. 2, and the smaller the percentage, the more the maximum stress applied to the bridge of the pulley than the pulley of Fig. It is small and has a strong pulley rigidity.

4 and 6, a compressor according to an embodiment of the present invention includes a casing 1, a compression mechanism 2 provided inside the casing 1 and compressing the refrigerant, (Not shown) provided on the outside of the driving mechanism (not shown) for transmitting the rotational force from the driving mechanism (not shown) to the compression mechanism 2 and the driving source And a power transmission mechanism for connecting and disconnecting the power transmission mechanism.

The compression mechanism 2 includes a piston 21 provided so as to be capable of reciprocating within the bore of the casing 1, a piston 21 coupled to the rotation shaft 3, rotated together with the rotation shaft 3, And a swash plate 22 for reciprocating the swash plate 22. The compression mechanism 2 is formed in a swash plate manner including the piston 21 and the swash plate 22 in the present embodiment. However, the compression mechanism 2 includes a orbiting scroll that receives the rotational force of the rotation shaft 3, And a scroll system including a fixed scroll engaged with the orbiting scroll.

The rotary shaft 3 has one end connected to the compression mechanism 2 and the other end projecting to the outside of the casing 1 through the casing 1, (6).

The power transmission mechanism is magnetized when power is applied to connect the driving source (not shown) and the rotary shaft 3, and when the power is shut off, the electromagnetic clutch is disengaged from the driving source (not shown) (4).

The pulley 5 is formed in a substantially annular shape and a driving belt (not shown) is mounted on the outer circumferential surface of the pulley 5 to transmit driving force from the driving source (not shown) to the pulley 5, And a bearing 8 for rotatably supporting the pulley 5 is interposed between the inner circumferential surface of the pulley 5 and the outer surface of the casing 1 .

A friction surface 54 is formed on one side surface of the pulley 5 so as to contact the disk 64 of the disk hub assembly 6, A field coil assembly receiving groove 55 into which the field coil assembly 7 is inserted can be formed.

The disk hub assembly 6 may include a hub 62 coupled to the rotating shaft 3 and a disk 64 extending from the hub 62 and selectively contacting and spacing the pulley 5 have.

The field coil assembly 7 may include a coil housing 72 and a coil 74 housed in the coil housing 72 and generating an electromagnetic force upon power application.

The spacing means (not shown) may be formed of an elastic member that forces the disc hub assembly 6 in a direction away from the pulley 5.

The compressor according to this embodiment according to this configuration can be operated as follows.

That is, the pulley 5 may be rotated by receiving driving force from the driving source (not shown).

In this state, when power is applied to the coil 74, the disk hub assembly 6 is moved toward the pulley 5 by the attraction force by the magnetic induction of the coil 74, Can be brought into close contact with each other. The disk hub assembly 6 and the pulley 5 are coupled so that the power of the drive source (not shown) is transmitted to the rotary shaft 3 through the pulley 5 and the disk hub assembly 6 . The rotary shaft (3) can compress the refrigerant by operating the compression mechanism (2) with the transmitted power.

On the other hand, when the power supply to the coil 74 is stopped, the suction force by the magnetic induction of the coil 74 is not generated, and the disk hub assembly 6 is rotated by the spacing means Can be moved away from the pulley (5) and separated from the pulley (5). That is, power transmission from the driving source (not shown) to the rotating shaft 3 can be interrupted. Then, the compression mechanism (2) is stopped, and the refrigerant compression can be stopped.

slots

532 and 535 extend through the

slots

532 and 535 to increase the attractive force between the pulley 5 and the hub assembly 6 and to secure the rigidity of the

pulley

5, 5 and the disk hub assembly 6 at the same time. That is, the

slots

532 and 535 are formed in such a manner that the suction force between the pulley 5 and the hub assembly 6 is included in a predetermined suction force range, and the stiffness of the pulley 5 is within a predetermined stiffness range And noise and vibration generated when the pulley 5 and the disc hub assembly 6 are in contact with each other may be included in a predetermined noise vibration range.

Specifically, the

slots

532 and 535 include a plurality of

inner slots

532 and 533 formed along the rotating direction of the friction plate 53 at positions spaced apart from each other by a predetermined first distance from the center of rotation of the friction plate 53 And a plurality of outer slots 535 formed along the rotational direction of the friction plate 53 at a position spaced apart from the center of rotation of the friction plate 53 by a second distance that is longer than the first distance.

The friction plate 53 of the pulley 5 includes an inner circumferential portion 531 positioned radially inwardly of the friction plate 53 with respect to the inner slot 532, An intermediate portion 534 positioned between the inner slot 532 and the outer slot 535, a plurality of inner slots 532 disposed between the inner slots 532 and the inner slot 535, A plurality of inner bridges 533 interposed between the inner and

outer portions

531 and 535 and connecting the inner and

outer portions

531 and 534 and a plurality of inner bridges 533 interposed between the plurality of

outer slots

535, 537 that are connected to each other.

The plurality of inner slots 533 and the plurality of inner bridges 533 are connected to the plurality of inner slots 533 and the plurality of outer bridges 536. The plurality of inner slots 533, The outer bridge 536 of the friction plate 53 is partially overlapped in the radial direction of the friction plate 53 and is not overlapped. That is, the plurality of outer bridges 536 include at least one overlapping outer bridge 5362 that overlaps with one of the plurality of inner bridges 533 in the radial direction of rotation, and one of the inner bridges 533 And at least one non-overlapping outer bridge 5364 that does not overlap in any rotational radial direction with respect to any of them. The plurality of inner bridges 533 includes the same number of overlapping inner bridges 5332 overlapping with the overlapping outer bridges 5362 in the radial direction of rotation so as to correspond to the overlapping outer bridges 5362, Overlapped inner bridge 5334 that does not overlap with any of the outer bridges 536 in the radial direction of rotation.

For this purpose, the pulley 5 according to the present embodiment may be formed so as to satisfy the following conditions.

That is, the inner slots 532 and the inner bridges 533 are formed by n, and the n inner slots 532 and the n inner bridges 533 are formed by rotating the friction plate 53 The n inner slots 532 may be formed in the same shape and the n inner bridges 533 may be formed in the same shape. In other words, each inner slot 532 is formed as an arcuate slot extending along the rotational direction of the friction plate 53, and is spaced apart from each other along the rotational direction of the friction plate 53, Are formed in the same shape and can be spaced apart at regular intervals along the rotational direction of the friction plate 53.

The plurality of outer slots 535 and the plurality of outer bridges 536 are formed in m different from the n slots, and the m outer slots 535 and the m outer bridges 536 are connected to the friction plate The m outer slots 535 may be formed in the same shape and the m inner bridges 533 may be formed in the same shape. That is, each outer slot 535 is formed as an arcuate slot extending along the rotational direction of the friction plate 53, and is spaced apart from each other along the rotational direction of the friction plate 53, and the plurality of outer slots 535, Are formed in the same shape and can be spaced apart at regular intervals along the rotational direction of the friction plate 53.

Here, a plurality of the

slots

532 and 535 may be formed, and the size (area) of the

slots

532 and 535 may be increased. This increases the magnetic flux passing from the field coil assembly 7 through the

slots

532 and 535 to the disk hub assembly 6 to thereby increase the magnetic flux transmitted between the pulley 5 and the disk hub assembly 6 The suction force can be increased. That is, the electromagnetic clutch performance can be improved.

The overlapping inner bridge 5362 and the overlapping inner bridge 5332 are overlapped with each other in the radial direction of rotation so that the pulley 5 and the disk hub assembly 6 by the plurality of slots 532, The maximum stress applied to the bridge of the pulley 5 can be reduced while maintaining the suction force between the pulleys. That is, the rigidity of the pulley 5 can be improved.

The non-overlapping inner bridge 5334 is overlapped with the inner slot 532 in the radial direction of rotation, and the non-overlapping inner bridge 5334 is overlapped with the outer slot 535 in the rotation radius direction, While maintaining the suction force between the pulley 5 and the disk hub assembly 6 due to the

slots

532 and 535 of the pulley 5 by the overlapping inner bridge 5362 and the overlap inner bridge 5332, It is possible to prevent resonance when the pulley 5 and the disk hub assembly 6 are in contact with each other. Thus, even if the stick slip occurs between the pulley 5 and the disk hub assembly 6, the vibration due to the stick slip can be prevented from being grown. Thus, the pulley 5 and the disk hub assembly 6 It is possible to reduce the noise and vibration generated during the contact.

Meanwhile, the pulley 5 according to the present embodiment is used to further improve the rigidity of the pulley 5 while maintaining the suction force and the noise vibration level between the pulley 5 and the disk hub assembly 6 at a predetermined level In order to maximize the effect of improving the rigidity of the pulley 5, the two superposed outer bridges 5362 are symmetrical with respect to the center of rotation of the friction plate 53 / RTI > In other words, when a pair of the overlapping outer bridges 5362 and the overlapping inner bridge 5332 overlap each other, the overlapping bridges are formed as two overlapping bridges, And the rotation centers of the two overlapping bridges and the friction plate 53 may be disposed on one axis.

That is, each of the plurality of inner slots 532 and the plurality of inner bridges 533 may be formed of six, and the plurality of outer slots 535 and the plurality of outer bridges 536 may be formed of eight have.

Specifically, the plurality of inner slots 532 include a first inner slot 532a, a second inner slot 532b, a third inner slot 532c, and a third inner slot 532c, which are sequentially formed along the rotational direction of the friction plate 53. [ A fourth inner slot 532d, a fifth inner slot 532e, and a sixth inner slot 532f.

The plurality of inner bridges 533 may include a first inner bridge 533a interposed between the first inner slot 532a and the second inner slot 532b, A second inner bridge 533b interposed between the third inner slots 532c and a third inner bridge 533c interposed between the third inner slot 532c and the fourth inner slot 532d, A fourth inner bridge 533d interposed between the fourth inner slot 532d and the fifth inner slot 532e and a fourth inner bridge 533d interposed between the fifth inner slot 532e and the sixth inner slot 532f. 5 inner bridge 533e and a sixth inner bridge 533f interposed between the sixth inner slot 532f and the first inner slot 532a.

The plurality of outer slots 535 may include a first outer slot 535a, a second outer slot 535b, a third outer slot 535c, and a second outer slot 535c which are sequentially formed along the rotational direction of the friction plate 53, A fourth outer slot 535d, a fifth outer slot 535e, a sixth outer slot 535f, a seventh outer slot 535g, and an eighth outer slot 535h.

The plurality of outer bridges 536 may include a first outer bridge 536a interposed between the first outer slot 535a and the second outer slot 535b and a second outer slot 535b interposed between the second outer slot 535b and the second outer slot 535b. A second outer bridge 536b interposed between the third outer slot 535c and a third outer bridge 536c interposed between the third outer slot 535c and the fourth outer slot 535d; A fourth outer bridge 536d interposed between the fourth outer slot 535d and the fifth outer slot 535e and a fourth outer bridge 536d interposed between the fifth outer slot 535e and the sixth outer slot 535f. A sixth outer bridge 536f interposed between the sixth outer slot 535f and the seventh outer slot 535g and a sixth outer bridge 536f interposed between the seventh outer slot 535g and the eighth outer slot 535e, A seventh outer bridge 536g interposed between the eighth outer slot 535h and the eighth outer slot 535h, And an eighth outer bridge 536h interposed between the first outer slots 535a.

The first inner bridge 533a and the first outer bridge 536a are overlapped with each other in the radial direction of rotation of the friction plate 53 and the fourth inner bridge 533d and the fifth outer bridge 536e Are overlapped with each other in the radial direction of rotation of the friction plate 53 and the first inner bridge 533a and the fourth inner bridge 533d are symmetrical with respect to the rotation center of the friction plate 53, The first outer bridge 536a and the fifth outer bridge 536e may be symmetrical with respect to the rotation center of the friction plate 53. [ At this time, the second outer bridge 536b overlaps with the second inner slot 532b and the friction plate 53 in the radial direction of rotation, and the third outer bridge 536c overlaps the third inner slot 532c And the fourth outer bridge 536d are overlapped with each other in the radial direction of rotation of the fourth inner slot 532d and the friction plate 53, The sixth outer bridge 536f is overlapped with the fifth inner slot 532e and the friction plate 53 in the radial direction of rotation and the seventh outer bridge 536g is overlapped with the sixth inner slot 532f, And the eighth outer bridge 536h may be overlapped with each other in the radial direction of rotation of the first inner slot 532a and the friction plate 53. In this case, The second inner bridge 533b is overlapped with the third outer slot 535c and the friction plate 53 in the radial direction of rotation and the third inner bridge 533c overlaps the fourth outer slot 535d And the fifth inner bridge 533e are superimposed on each other in the radial direction of rotation of the seventh outer slot 535g and the

friction plate

53, 6 inner bridge 533f may overlap each other in the radial direction of rotation of the eighth outer slot 535h and the friction plate 53. [

In this case, the relative positions of the plurality of inner slots 533 and the plurality of outer slots 535 and the plurality of outer bridges 536 relative to the inner slots 532 and the plurality of inner bridges 533 are changed The two overlapping bridges may be formed symmetrically with respect to the center of rotation of the friction plate 53. In this case, the two overlapping bridges may be formed symmetrically with respect to the center of rotation of the friction plate 53. [

The pulleys 5 may be formed to have a total sum of the widths of the plurality of outer bridges 536 in order to improve the attractive force between the pulley 5 and the dam assembly 62 while maintaining the rigidity of the pulleys 5, May be less than or equal to the sum of the widths of the plurality of inner bridges (533). Here, the width of the bridge means the thickness of the bridge measured along the rotational direction of the friction plate 53.

As shown in FIG. 6, the electromagnetic clutch 4 and the compressor including the electromagnetic clutch 4 according to this embodiment according to the present embodiment maintain the suction force between the pulley 5 and the disk hub assembly 6 at the same level , The maximum stress applied to the bridge of the pulley (5) is reduced to improve the rigidity of the pulley (5), and the generation of resonance can be suppressed to reduce noise and vibration.

The plurality of inner slots 532 and the plurality of inner bridges 533 are each formed of six, and the plurality of outer slots 535 and the plurality of outer bridges 536 are 8. However, the present invention is not limited thereto.

5, in the pulley 5 according to another embodiment of the present invention, the plurality of inner slots 532 and the plurality of inner bridges 533 are each formed of six, and the plurality The four outer bridges 536 are partially overlapped with the six inner bridges 533 in the radial direction of rotation and are partially overlapped with each other in the radial direction of the six inner bridges 533. The outer bridges 536 and the outer bridges 536, .

The plurality of outer slots 535 may include a first outer slot 535a, a second outer slot 535b, a third outer slot 535c, and a second outer slot 535c which are sequentially formed along the rotational direction of the friction plate 53 And a fourth outer slot 535d.

The plurality of outer bridges 536 may include a first outer bridge 536a interposed between the first outer slot 535a and the second outer slot 535b and a second outer slot 535b interposed between the second outer slot 535b and the second outer slot 535b. A second outer bridge 536b interposed between the third outer slot 535c and a third outer bridge 536c interposed between the third outer slot 535c and the fourth outer slot 535d; And a fourth outer bridge 536d interposed between the fourth outer slot 535d and the fifth outer slot 535e.

The first inner bridge 533a and the first outer bridge 536a are overlapped with each other in the radial direction of rotation of the friction plate 53 and the fourth inner bridge 533d and the third outer bridge 536c are overlapped with each other, The first inner bridge 533a and the fourth inner bridge 533d are symmetrically symmetrical with respect to the center of rotation of the friction plate 53, The first outer bridge 536a and the third outer bridge 536c may be symmetrical with respect to the rotation center of the friction plate 53. [ At this time, the second outer bridge 536b overlaps with the third inner slot 532c and the friction plate 53 in the radial direction of rotation, and the fourth outer bridge 536d overlaps the sixth inner slot 532f ) And the friction plate (53). The second inner bridge 533b and the third inner bridge 533c overlap each other in the radial direction of rotation of the second outer slot 535b and the friction plate 53 and the third outer slot 535c And the fifth inner bridge 533e are superimposed on each other in the radial direction of rotation of the fourth outer slot 535d and the

friction plate

53, 6 inner bridge 533f may overlap each other in the radial direction of rotation of the first outer slot 535a and the friction plate 53. [

In the case of such another embodiment of the present invention, its operation and effect can be greatly reduced as compared with the above-described embodiment. 6, while the suction force between the pulley 5 and the damper hub assembly 6 is maintained at the same level as that of the other conventional embodiment (the embodiment shown in FIG. 3) The maximum stress imparted to the bridge of the pulley 5 is reduced to the same level as that of the prior art embodiment (the embodiment shown in Fig. 2), so that the stiffness of the pulley 5 is reduced And the generation of resonance is suppressed, so that noise and vibration can be reduced.

However, in the case of another embodiment of the present invention, resonance occurrence can be further suppressed than in the above-described embodiments. That is, referring to FIG. 6, in the case of the above-described embodiment (the embodiment shown in FIG. 4), there is no overlapping frequency, but a difference between frequencies of some regions (for example, 4th and 5th, 7th and 8th) There is a possibility that resonance occurs in the region in a small amount. However, in another embodiment of the present invention, there is no frequency overlapping with each other, and a region where the difference between the frequencies is small can be eliminated.

The present invention provides an electromagnetic clutch capable of increasing suction force between a pulley and a disk hub assembly, ensuring rigidity of the pulley, and noise and vibration reduction caused by contact between the pulley and the disk hub assembly, and a compressor including the electromagnetic clutch.

Claims

A pulley (5) rotated by receiving power from a driving source;

A disk hub assembly (6) engaged with the rotary shaft (3) of the compressor and selectively in contact with and spaced from the pulley (5); And

And a field coil assembly (7) magnetized when power is applied to bring the pulley (5) and the disc hub assembly (6) into contact with each other,

The pulley (5)

A plurality of inner slots 532 and a plurality of outer slots 535 for transferring the suction flux of the field coil assembly 7 to the disk hub assembly 6;

A plurality of inner bridges (533) interposed between the plurality of inner slots (532); And

And a plurality of outer bridges (536) interposed between the plurality of outer slots (535)

Wherein the plurality of outer bridges (536) partially overlap with the plurality of inner bridges (533) in the radial direction and are formed so as not to overlap each other.
The method according to claim 1,

The pulley (5) includes a friction plate (53) capable of contacting the disk hub assembly (6)

The friction plate (53)

The plurality of inner slots (532) formed along the rotational direction of the friction plate (53) at a position spaced apart from the center of rotation of the friction plate (53) by a predetermined first distance;

The plurality of outer slots (535) formed along the rotational direction of the friction plate (53) at a position spaced apart from the center of rotation of the friction plate (53) by a second distance that is longer than the first distance;

An inner circumferential portion 531 positioned radially inwardly of the friction plate 53 with respect to the inner slot 532;

An outer peripheral portion 537 positioned radially outward of the friction plate 53 with respect to the outer slot 535;

An intermediate portion 534 positioned between the inner slot 532 and the outer slot 535;

The plurality of inner bridges 533 interposed between the plurality of inner slots 532 and connecting the inner peripheral portion 531 and the intermediate portion 534; And

And a plurality of outer bridges (536) interposed between the plurality of outer slots (535) and connecting the intermediate portion (534) to the outer peripheral portion (537)

The plurality of outer bridges (536)

An overlapping outer bridge (5362) overlapping with one of the plurality of inner bridges (533) in a rotating radial direction; And

And a non-overlapping outer bridge (5364) that does not overlap with any of the plurality of inner bridges (533) in the radial direction of rotation.
3. The method of claim 2,

The plurality of inner slots 532 and the plurality of inner bridges 533 are each formed of n,

The n inner slots 532 and the n inner bridges 533 are alternately formed along the rotational direction of the friction plate 53. The n inner slots 532 are formed in the same shape, n inner bridges 533 are formed in the same shape,

The plurality of outer slots 535 and the plurality of outer bridges 536 are formed in m different from the n slots,

The m outer slots 535 and the m outer bridges 536 are alternately formed along the rotational direction of the friction plate 53. The m outer slots 535 are formed in the same shape, and the m inner bridges 533 are formed in the same shape with each other.
The method of claim 3,

Wherein the overlapping outer bridge (5362) is formed of two pieces.
5. The method of claim 4,

Wherein the two overlapping outer bridges (5362) are formed at positions symmetrical to each other with respect to the center of rotation of the friction plate (53).
6. The method of claim 5,

The plurality of inner slots 532 and the plurality of inner bridges 533 are each formed of six,

Wherein the plurality of outer slots (535) and the plurality of outer bridges (536) are each formed of eight.
The method according to claim 6,

The plurality of inner slots 532 may include a first inner slot 532a, a second inner slot 532b, a third inner slot 532c, and a fourth inner slot 532b, which are sequentially formed along the rotational direction of the friction plate 53. [ A slot 532d, a fifth inner slot 532e, and a sixth inner slot 532f,

The plurality of inner bridges 533 includes a first inner bridge 533a interposed between the first inner slot 532a and the second inner slot 532b and a second inner bridge 533b interposed between the second inner slot 532b and the third inner slot 532b. A second inner bridge 533b interposed between the inner slots 532c and a third inner bridge 533c interposed between the third inner slot 532c and the fourth inner slot 532d, A fourth inner bridge 533d interposed between the slot 532d and the fifth inner slot 532e and a fourth inner bridge 533d interposed between the fifth inner slot 532e and the sixth inner slot 532f, (533e) and a sixth inner bridge (533f) interposed between the sixth inner slot (532f) and the first inner slot (532a)

The plurality of outer slots 535 may include a first outer slot 535a, a second outer slot 535b, a third outer slot 535c, and a fourth outer slot 535c, which are sequentially formed along the rotational direction of the friction plate 53. [ A fifth outer slot 535e, a sixth outer slot 535f, a seventh outer slot 535g and an eighth outer slot 535h,

The plurality of outer bridges 536 may include a first outer bridge 536a interposed between the first outer slot 535a and the second outer slot 535b and a second outer bridge 536b interposed between the second outer slot 535b and the third outer slot 535b. A third outer bridge 536b interposed between the third outer slot 535c and the fourth outer slot 535d and a second outer bridge 536b interposed between the fourth outer slot 535c and the fourth outer slot 535c, A fourth outer bridge 536d interposed between the slot 535d and the fifth outer slot 535e and a fourth outer bridge 536d interposed between the fifth outer slot 535e and the sixth outer slot 535f. A sixth outer bridge 536f interposed between the sixth outer slot 535f and the seventh outer slot 535g and a sixth outer bridge 536f interposed between the seventh outer slot 535g and the eighth outer slot 535h. A seventh outer bridge 536g interposed between the eighth outer slot 535h and the first sub- And an eighth outer bridge (536h) interposed between the rotor slots (535a).
8. The method of claim 7,

The first inner bridge 533a and the first outer bridge 536a are overlapped with each other in the radial direction of rotation of the friction plate 53,

The fourth inner bridge 533d and the fifth outer bridge 536e are overlapped with each other in the radial direction of rotation of the friction plate 53,

The first inner bridge 533a and the fourth inner bridge 533d are symmetrical with respect to the rotation center of the friction plate 53,

Wherein the first outer bridge (536a) and the fifth outer bridge (536e) are symmetrical with respect to the rotation center of the friction plate (53).
9. The method of claim 8,

The second outer bridge 536b is overlapped with the second inner slot 532b and the friction plate 53 in the radial direction of rotation,

The third outer bridge 536c is overlapped with the third inner slot 532c in the radial direction of rotation of the friction plate 53,

The fourth outer bridge 536d is overlapped with the fourth inner slot 532d and the friction plate 53 in the radial direction of rotation,

The sixth outer bridge 536f overlaps the fifth inner slot 532e and the friction plate 53 in the radial direction of rotation,

The seventh outer bridge 536g is overlapped with the sixth inner slot 532f in the radial direction of rotation of the friction plate 53,

The eighth outer bridge 536h overlaps the first inner slot 532a and the friction plate 53 in the radial direction of rotation,

The second inner bridge 533b is overlapped with the third outer slot 535c in the radial direction of rotation of the friction plate 53,

The third inner bridge 533c is overlapped with the fourth outer slot 535d and the friction plate 53 in the radial direction of rotation,

The fifth inner bridge 533e overlaps the seventh outer slot 535g and the friction plate 53 in the radial direction of rotation,

The sixth inner bridge (533f) overlaps the eighth outer slot (535h) and the friction plate (53) in the radial direction of rotation.
6. The method of claim 5,

The plurality of inner slots 532 and the plurality of inner bridges 533 are each formed of six,

Wherein the plurality of outer slots (535) and the plurality of outer bridges (536) are each formed of four.
11. The method of claim 10,

The plurality of inner slots 532 may include a first inner slot 532a, a second inner slot 532b, a third inner slot 532c, and a fourth inner slot 532b, which are sequentially formed along the rotational direction of the friction plate 53. [ A slot 532d, a fifth inner slot 532e, and a sixth inner slot 532f,

The plurality of inner bridges 533 includes a first inner bridge 533a interposed between the first inner slot 532a and the second inner slot 532b and a second inner bridge 533b interposed between the second inner slot 532b and the third inner slot 532b. A second inner bridge 533b interposed between the inner slots 532c and a third inner bridge 533c interposed between the third inner slot 532c and the fourth inner slot 532d, A fourth inner bridge 533d interposed between the slot 532d and the fifth inner slot 532e and a fourth inner bridge 533d interposed between the fifth inner slot 532e and the sixth inner slot 532f, (533e) and a sixth inner bridge (533f) interposed between the sixth inner slot (532f) and the first inner slot (532a)

The plurality of outer slots 535 may include a first outer slot 535a, a second outer slot 535b, a third outer slot 535c, and a fourth outer slot 535c, which are sequentially formed along the rotational direction of the friction plate 53. [ Slot 535d,

The plurality of outer bridges 536 includes a first outer bridge 536a interposed between the first outer slot 535a and the second outer slot 535b and a second outer bridge 536b interposed between the second outer slot 535b and the third outer slot 535b. A third outer bridge 536b interposed between the third outer slot 535c and the fourth outer slot 535d and a second outer bridge 536b interposed between the fourth outer slot 535c and the fourth outer slot 535c, And a fourth outer bridge (536d) interposed between the slot (535d) and the fifth outer slot (535e).
12. The method of claim 11,

The first inner bridge 533a and the first outer bridge 536a are overlapped with each other in the radial direction of rotation of the friction plate 53,

The fourth inner bridge 533d and the third outer bridge 536c are overlapped with each other in the radial direction of rotation of the friction plate 53,

The first inner bridge 533a and the fourth inner bridge 533d are symmetrical with respect to the rotation center of the friction plate 53,

Wherein the first outer bridge (536a) and the third outer bridge (536c) are symmetrical with respect to the rotation center of the friction plate (53).
13. The method of claim 12,

The second outer bridge 536b is overlapped with the third inner slot 532c in the radial direction of rotation of the friction plate 53,

The fourth outer bridge 536d is overlapped with the sixth inner slot 532f and the friction plate 53 in the radial direction of rotation,

The second inner bridge 533b is overlapped with the second outer slot 535b and the friction plate 53 in the radial direction of rotation,

The third inner bridge 533c overlaps the third outer slot 535c and the friction plate 53 in the radial direction of rotation,

The fifth inner bridge 533e overlaps the fourth outer slot 535d and the friction plate 53 in the radial direction of rotation,

The sixth inner bridge (533f) overlaps the first outer slot (535a) and the friction plate (53) in the radial direction of rotation.
3. The method of claim 2,

Wherein the pulley (5) is formed such that the sum of the widths of the plurality of outer bridges (536) is smaller than or equal to the sum of the widths of the plurality of inner bridges (533).
A casing (1);

A compression mechanism (2) provided in the casing (1) and compressing the refrigerant;

A rotating shaft (3) for transmitting rotational force from a driving source provided outside the casing (1) to the compression mechanism (2); And

And a power transmitting mechanism for selectively connecting and disconnecting the driving source and the rotating shaft (3)

The power transmission mechanism includes the electromagnetic clutch (4) according to any one of claims 1 to 14.