JP2018013133A - Electromagnetic clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic clutch which can surely bring a slip ring into contact with a brush, and can improve energization reliability.SOLUTION: An electromagnetic clutch 40 comprises a drive-side rotor 1, an electromagnetic coil 2 for generating an electromagnetic attraction force by energization, and an armature 8 which is attracted to the drive-side rotor 1 by the electromagnetic attraction force which is generated by the electromagnetic coil 2. The electromagnetic clutch 40 transmits rotation to a rotating shaft 13 from a rotation drive source via the rotor 1 and the armature 8 by the attraction of the armature 8 to the rotor 1. The electromagnetic clutch 40 has a slide energization mechanism including brushes 22, 23 arranged at an inner peripheral side of a boss part 6a, and slip rings 19, 20 with which the brushes 22, 23 come into pressure-contact and slidable contact, and is configured to energize the electromagnetic coil 2 through the slide energization mechanism. Mutual contact of the brushes 22, 23 and the slip rings 19, 20 are maintained by a magnetic force.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electromagnetic clutch.

  In the field of electromagnetic clutches, a coil rotary clutch having a highly efficient magnetic circuit is known for the purpose of power saving and light weight when used in a belt drive compressor for a vehicle. Since the coil rotation type clutch has a structure in which the coil is built in the rotor, a method of energizing the coil is a problem. For example, Patent Document 1 proposes a structure in which an energization method (brush method) using a brush is used for a power transmission portion, and the power transmission portion is disposed in a boss of a front housing of a compressor. In this configuration, the brush on the power supply side is slidably contacted with the slip ring on the coil side, and the coil can be energized via the brush and the slip ring.

Japanese Patent Laid-Open No. 11-311263

  However, in the brush system described in Patent Literature 1, the brush may jump due to the compression vibration of the compressor or the actual vehicle vibration. When the brush jumps, the brush and the slip ring are separated from each other to cut off current, and there are problems such as occurrence of sparks and breakage of the brush tip.

  This invention is made | formed in view of such a subject, The objective is to provide the electromagnetic clutch which can make a slip ring and a brush contact reliably and can improve electricity supply reliability.

  In order to solve the above-described problems, an electromagnetic clutch (40, 40A) according to the present invention includes a boss portion (6a) protruding in a cylindrical shape outward in the axial direction in a housing (6), and the center of the boss portion. An electromagnetic clutch (40, 40A) that is applied to a rotary machine (5) having a rotary shaft (13) disposed at a portion thereof and intermittently transmits rotation to the rotary shaft, the rotary member (1), An electromagnetic coil (2) that is electrically insulated from the rotating member and generates an electromagnetic attractive force when energized, and is disposed opposite to the rotating member, and is attracted to the rotating member by the electromagnetic attractive force generated by the electromagnetic coil. An armature (8), wherein the armature is adsorbed to the rotating member, and configured to transmit rotation from a rotational drive source to the rotating shaft via the rotating member and the armature, A sliding energization mechanism including a brush (22, 23, 22A, 23A) disposed on the inner peripheral side of the sleeve portion and a slip ring (19, 20) on which the brush slides against pressure, and the sliding The electromagnetic coil is energized through an energization mechanism, and the brush and the slip ring are kept in contact with each other by magnetic force.

  With this configuration, it is possible to make the contact state between the brush and the slip ring stronger by magnetically attracting the brush and the slip ring to each other, and the brush jumps due to the compression vibration of the compressor and the vibration of the actual vehicle. It can prevent suitably.

  ADVANTAGE OF THE INVENTION According to this invention, a slip ring and a brush can be made to contact reliably and the electromagnetic clutch which can improve electricity supply reliability can be provided.

FIG. 1 is a longitudinal sectional view showing the configuration of the electromagnetic clutch according to the first embodiment of the present invention. 2 is a cross-sectional view taken along the line II-II in FIG. 1 and showing the brush, the brush holding member, and the boss portion. FIG. 3 is an enlarged longitudinal sectional view of a portion of the brush and the brush holding member in FIG. FIG. 4 is a longitudinal sectional view showing the configuration of the electromagnetic clutch according to the second embodiment of the present invention. FIG. 5 is a cross-sectional view taken along the line VV in FIG. 4 and is an axial cross-sectional view showing portions of the brush, the brush holding member, and the boss portion. FIG. 6 is an enlarged longitudinal sectional view of the brush and the brush holding member in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same constituent elements in the drawings will be denoted by the same reference numerals as much as possible, and redundant description will be omitted.

[First Embodiment]
The first embodiment will be described with reference to FIGS. First, the configuration of the electromagnetic clutch 40 according to the first embodiment will be described.

  The electromagnetic clutch 40 according to the first embodiment is a coil rotation type clutch configured by installing the electromagnetic coil 2 for generating an electromagnetic attractive force on the rotating member side. In the coil rotation type clutch, the magnetic circuit through which the magnetic flux by the electromagnetic coil 2 passes can be constituted by only the rotation member (drive type rotor 1) and the armature 8 magnetically attracted to the rotation member, so that the magnetic loss is very small. Thus, there is an advantage that the magnetic efficiency can be greatly improved as compared with the fixed coil type. Hereinafter, each component of the electromagnetic clutch 40 will be described.

  As shown in FIG. 1, the drive-side rotor 1 is integrally joined with a pulley portion 1a having a multiple V-groove engaged with a multiple V-belt on the outer periphery thereof. The drive-side rotor 1 is a drive-side rotating member that rotates by receiving rotational force from an automobile engine via a belt (not shown), and is made of an iron-based metal (ferromagnetic material) such as low carbon steel and has a U-shaped cross section. Are formed into a double ring shape. An annular recess 1d is formed between the inner peripheral cylindrical portion 1b and the outer peripheral cylindrical portion 1c of the drive side rotor 1, and a friction surface 1e is formed on the side surface in the radial direction of the rotor 1.

  The electromagnetic coil 2 generates an electromagnetic attractive force, and is installed in the recess 1 d of the drive side rotor 1. The electromagnetic coil 2 is insulated and fixed to the concave portion 1d by a resin member 3 formed in the concave portion 1d in a state of being wound on a resin winding frame (not shown). Therefore, the electromagnetic coil 2 rotates integrally with the drive side rotor 1.

  The friction plate 4 is made of an iron-based metal (ferromagnetic material) such as low-carbon steel, and has an overall ring shape. The protrusions 4a in the inner diameter direction are provided at a plurality of locations in the circumferential direction of the ring shape. And the protrusion part 4b to an outer-diameter direction is integrally molded. The friction plate 4 is supported and fixed to the axial end portions (the left end portion in FIG. 1) of the inner peripheral cylindrical portion 1b and the outer peripheral cylindrical portion 1c of the rotor 1 at the plurality of protrusions 4a and protrusions 4b. The

  The compressor 5 is a driven device (rotary machine) and includes a front housing 6 positioned on the electromagnetic clutch 40 side. The front housing 6 is made of an aluminum-based metal, and a boss portion (fixing member) 6a protruding in a cylindrical shape outward in the axial direction is integrally formed at the center thereof. Here, the compressor 5 is for refrigerant compression of a refrigeration cycle of an automotive air conditioner, and may be any type such as a known swash plate type, vane type, scroll type or the like.

  The bearing 7 rotatably supports the drive-side rotor 1 on the boss portion 6 a of the front housing 6. In this example, the bearing 7 is rotatably held between an outer ring 7a fixed to the inner peripheral surface of the drive-side rotor 1, an inner ring 7b fixed to the outer peripheral surface of the boss portion 6a, and the both 7a and 7b. It comprises a rolling bearing having a ball 7c.

  The armature 8 is disposed opposite to the friction surface 1e of the rotor 1 and the friction plate 4, and is formed of a ferrous metal (ferromagnetic material) in a ring-shaped flat plate shape. This armature 8 is held by a spring force of a leaf spring (elastic connecting member) 9 at a position (position shown in FIG. 1) that is a predetermined minute distance away from the friction surface 1e of the rotor 1 when the electromagnetic coil 2 is not energized. It has become.

  The plate springs 9 are of a thin and thin plate shape, and a plurality of plate springs 9 are arranged in the circumferential direction of the armature 8. One end of each plate spring 9 is connected to the armature 8 by a rivet 10 a, and the other end of each plate spring 9. The part is connected to the hub 11 by a rivet 10b.

  The hub 11 is a driven side rotating member, and is formed in a shape having a plate portion 11a and a central cylindrical portion 11b extending in a radial direction with an iron-based metal, and at a plurality of locations on the outer peripheral side of the plate portion 11a. A stopper member 12 made of an elastic material such as rubber is mounted, and the stopper member 12 defines the axial position of the armature 8 when the clutch is disconnected (when the coil is not energized). Further, since the armature 8 is pressed in the axial direction (rotor 1 side) by the thickness of the stopper member 12 from the surface of the plate portion 11a of the hub 11, the plate spring 9 is elastically deformed. A spring force is generated, and the armature 8 is held at a predetermined axial position when the clutch is disengaged by the spring force.

  The central cylindrical portion 11b of the hub 11 is fitted to the rotating shaft 13 of the compressor 5 while being prevented from rotating by spline coupling or the like. The hub 11 is integrally connected to the rotary shaft 13 by screwing a nut 14 into the male screw portion 13 a at the tip of the rotary shaft 13. A shaft seal device 15 is provided on the outer periphery of the rotary shaft 13 inside the compressor 5 to prevent the lubricating oil, refrigerant, etc. inside the compressor 5 from leaking outside.

  Next, the configuration of the energization path to the electromagnetic coil 2 that rotates with the rotor 1 will be described. In 1st Embodiment, it has the brushes 22 and 23 arrange | positioned in the position of the inner peripheral side of the compressor boss | hub part 6a which supports the bearing 7, and the slip rings 19 and 20 with which this brushes 22 and 23 carry out pressure-contact sliding. A sliding energization mechanism is configured. Specifically, the layout of the sliding energization mechanism is configured as follows. In the recess 1 d of the rotor 1, the winding start end portion and winding end end portion of the electromagnetic coil 2 are taken out to the friction plate 4 side (armature 8 side), and the positive lead wire 16 is connected to one of the both end portions. Further, the negative lead wire 17 is connected to the other end. In the present embodiment, both the lead wires 16 and 17 are arranged at symmetrical positions approximately 180 ° apart in the clutch circumferential direction, but only the lead wire 16 on the positive electrode side is shown in FIG. The lead wire 17 on the negative electrode side is not shown.

  A slip ring holding member 18 is disposed on the inner peripheral side of the rotor 1, and the holding member 18 is formed in an approximately ring shape extending in the rotor radial direction with an electric insulating material such as resin. In this example, the relationship of the diameter of the positive side slip ring 19 <the diameter of the negative side slip ring 20 is set, and both the slip rings 19 and 20 are arranged concentrically and inserted into the inner peripheral portion of the holding member 18. Molding. As a result, the two slip rings 19 and 20 on the positive electrode side and the negative electrode side are positioned on the inner peripheral side of the boss portion 6 a and are integrally held by the holding member 18.

  The outer peripheral portion 18 a of the slip ring holding member 18 described above is fitted and fixed (for example, adhesively fixed) to the fitting concave groove 1 f formed in the inner peripheral cylindrical portion 1 b of the rotor 1. Thereby, the slip ring holding member 18 can be integrated with the inner peripheral cylindrical portion 1 b of the rotor 1, and the slip ring holding member 18 rotates integrally with the rotor 1. Both the slip rings 19 and 20 are made of a conductive metal such as copper. In this example, the positive-side slip ring 19 positioned on the inner peripheral side has a positive-side terminal piece (not shown) and the negative-electrode positioned on the outer peripheral side. The side slip ring 20 is integrally formed with a negative electrode terminal piece (not shown) by a method such as cutting or pressing. Then, the end of the positive lead wire 16 is mechanically caulked and bonded to the positive terminal strip of the positive slip ring 19 and then soldered, whereby the positive slip ring 19 and the positive lead 16 are connected. Mechanically and electrically coupled. Further, the negative electrode side slip ring 20 and the negative electrode side lead wire 17 are mechanically and electrically coupled by the same means.

  On the other hand, a cylindrical space 21 is formed between the central cylindrical portion 11b of the hub 11 connected to the rotary shaft 13 of the compressor 5 and the inner peripheral surface of the boss portion 6a. The brushes 22 and 23 on the positive electrode side and the negative electrode side and the holding member 24 for the brushes 22 and 23 are arranged. The brush holding member 24 is formed of an electrical insulating material such as resin. As shown in FIG. 2, two brush housing recesses 24 a and 24 b having an arcuate cross section are formed at symmetrical positions approximately 180 ° apart in the circumferential direction of the brush holding member 24. The brush housing recesses 24a and 24b are formed in a shape having a sufficient axial dimension (depth) extending along the axial direction of the brush holding member 24 as shown in FIGS. The bottom is closed by a ring-shaped bottom part 24c.

  The brushes 22 and 23 are formed in a circular arc shape along the brush storage recesses 24a and 24b, and the positive brush 22 is stored in one brush storage recess 24a so as to be slidable in the axial direction. A coil spring 25 is disposed as an elastic pressing member between one end portion 22 and the bottom surface portion 24c of the brush housing recess 24a. Therefore, the other end portion of the positive brush 22 is always in pressure contact with the positive slip ring 19 by the spring force of the coil spring 25.

  Similarly, the negative electrode side brush 23 is accommodated in the other brush accommodating recess 24b so as to be slidable in the axial direction, and elastically pressed between one end of the negative electrode side brush 23 and the bottom surface 24c of the brush accommodating recess 24b. A coil spring 26 is disposed as a member. Therefore, the other end portion of the negative brush 23 is always in pressure contact with the negative slip ring 20 by the spring force of the coil spring 26.

  The brushes 22 and 23 are formed by mixing raw material powder (mainly copper powder) with magnet powder and pressing and solidifying the powder, as in the conventional case. Thereby, the brushes 22 and 23 can generate the magnetic force by magnet powder over the whole. The slip rings 19 and 20 are made of a magnetic material such as an iron-based metal and can be energized. Therefore, the brushes 22 and 23 and the slip rings 19 and 20 are not only pressed by the spring force of the coil springs 25 and 26 described above, but also by the magnetic force generated by the magnetic powder contained in the brushes 22 and 23. 23 adsorbs the slip rings 19 and 20 so that the mutual contact state can be maintained firmly. In addition, the magnetic force which brushes 22 and 23 can generate | occur | produce can be adjusted with the ratio of the magnet powder mix | blended with copper powder. It is preferable that the brushes 22 and 23 can generate a magnetic force that can sufficiently overcome the compression vibration and actual vehicle vibration of the compressor 5.

  Further, in the brush holding member 24, two projecting portions 24d and 24e extending in the axial direction are formed on the outer peripheral surface of the portion where the brush housing recesses 24a and 24b are formed so as to project at a symmetrical position separated by 180 °. As shown in FIG. 1, two recesses 6b and 6c into which the two protrusions 24d and 24e are inserted are formed on the inner peripheral surface of the boss 6a. Therefore, the brush holding member 24 is positioned and held on the inner peripheral surface of the boss 6a by the fitting structure of the two protrusions 24d and 24e and the two recesses 6b and 6c. The brush holding member 24 is fixed to the front housing 6 by screw fastening or the like.

  One end of each of the positive electrode side brush 22 and the negative electrode side brush 23 is electrically connected to one end of a lead wire (pigtail) 27, 28 on the positive electrode side and the negative electrode side, respectively. An external control circuit that passes through the bottom surface portion 24c of 24a, 24b and is taken out to the surface of the brush holding member 24 on the compressor 5 side (the right side end surface in FIGS. 1 and 3) and intermittently energizes the electromagnetic coil 2. It is designed to be electrically connected.

  In the front housing 6 of the compressor 5, a ring-shaped weir 6 d that protrudes toward the outer peripheral surface of the rotary shaft 13 is formed on the outer side portion in the axial direction from the shaft seal device 15. An oil discharge hole 6e for discharging the leaked oil from the shaft seal device 15 as indicated by an arrow A is formed in the lower portion in the axially inner portion of the ring-shaped weir 6d.

  As shown in FIG. 3, a ring-shaped concave groove 24g is formed on the outer wall surface (the surface on the compressor 5 side) of the bottom surface portion 24c of the brush holding member 24, and the concave groove 24g is shown in FIG. As described above, an O-ring 29 made of an elastic material such as rubber is disposed as an elastic sealing material, and this O-ring 29 is pressure-bonded and held between the bottom surface portion 24 c of the brush holding member 24 and the outer wall surface of the front housing 6. Yes.

  Further, as shown in an enlarged view in FIG. 3, in the brush holding member 24, the outer side in the axial direction from the sliding surface of the slip rings 19, 20 and the brushes 22, 23 is located on the inner peripheral side of the brushes 22, 23. A cylindrical sleeve (protruding portion) 30 protruding to the side is integrally formed. An acute-angle shaped portion 30a having a sharp cross-sectional shape is formed at the distal end portion of the sleeve 30 outward in the axial direction. Here, the acute-angle shaped portion 30 a is formed on the same surface as the outer peripheral surface of the main body portion of the sleeve 30.

  In the sleeve 30, a groove 30 b is formed over the entire circumference in the circumferential direction, adjacent to the acute-angled portion 30 a located at the distal end, at a site on the inner side in the axial direction from the acute-angled portion 30 a. Due to the concave groove 30b, leakage from the inside of the compressor 5 through the shaft sealing device 15 leaks outward in the axial direction, and further leaks through a minute gap between the ring-shaped weir 6d and the rotary shaft 13. Since the oil is stored in the concave groove 30b and can be dropped downward by gravity, the leaked oil can be reliably prevented from reaching the sliding surfaces of the brushes 22 and 23.

  Next, the operation of the electromagnetic clutch 40 according to the first embodiment will be described. Since the rotor 1 is rotatably supported by the bearing 7 on the outer peripheral surface of the boss portion 6a of the front housing 6, when an automobile engine (not shown) is operated, rotation of the crank pulley of the engine is not performed by a belt (not shown). ) And the rotor 1 and the electromagnetic coil 2 always rotate.

  As the rotor 1 and the electromagnetic coil 2 rotate, the lead wires 16 and 17, the slip ring holding member 18, and the slip rings 19 and 20 also rotate together. On the other hand, the brushes 22, 23, the brush holding member 24, the coil springs 25, 26, etc. are all held on the boss portion 6a side and do not rotate. Therefore, the end faces in the axial direction of the brushes 22 and 23 are pressed against the rotating slip rings 19 and 20 by the spring force of the coil springs 25 and 26 and slide. At this time, the slip rings 19 and 20 are attracted to the brushes 22 and 23 by the magnetic force generated by the magnetic powder contained in the brushes 22 and 23, and the contact between the brushes 22 and 23 and the slip rings 19 and 20 is maintained. Is done.

  In order to operate the compressor 5 in the above state, when the voltage of the in-vehicle power source battery is applied between the lead wires (pigtails) 27 and 28 of the brushes 22 and 23 by an external control circuit (not shown), the above-described members (16, 17, 19, 20, 22, 23, 27, 28), current flows through the electromagnetic coil 2 through the energizing path. Then, as shown in FIG. 1, the magnetic flux flows in the magnetic circuit M configured between the rotor 1 and the friction plate 4 and the armature 8, so that the friction surface 1 e of the rotor 1 and the friction plate 4 and the armature 8 Electromagnetic attractive force is generated between them. As a result, the armature 8 is attracted and attracted to the friction surface 1e of the rotor 1 and the friction plate 4 against the axial elastic force of the leaf spring 9 (the force in the left direction in FIG. 1).

  As a result, the rotor 1 and the armature 8 rotate together, and the armature 8 rotates together with the hub 11 via the leaf spring 9 and the rivets 10a and 10b. Accordingly, the rotation of the rotor 1 is transmitted to the rotary shaft 13 of the compressor 5 via the hub 11 and the compressor 5 is operated. On the other hand, when the compressor 5 is stopped, the energization to the electromagnetic coil 2 is interrupted by the external control circuit. As a result, the electromagnetic attractive force disappears, so that the armature 8 is separated from the friction surface 1e of the rotor 1 and the friction plate 4 by the axial elastic force of the leaf spring 9, and the rotation transmission to the rotating shaft 13 of the compressor 5 is cut off. Therefore, the compressor 5 stops.

  Next, the effect of the electromagnetic clutch 40 according to the first embodiment will be described. The electromagnetic clutch 40 according to the first embodiment is applied to the compressor 5 in which the housing 6 includes a boss portion 6a that protrudes in a cylindrical shape outward in the axial direction, and the rotating shaft 13 is disposed at the center of the boss portion 6a. Then, the rotation transmission to the rotating shaft 13 is interrupted. The electromagnetic clutch 40 is disposed electrically insulated from the drive side rotor 1, the drive side rotor 1, and is disposed opposite to the drive side rotor 1 to generate an electromagnetic attractive force when energized. And an armature 8 that is attracted to the drive-side rotor 1 by electromagnetic attracting force. The electromagnetic clutch 40 is configured to transmit rotation from the rotational drive source to the rotary shaft 13 via the rotor 1 and the armature 8 when the armature 8 is attracted to the rotor 1. The electromagnetic clutch 40 has a sliding energization mechanism including brushes 22 and 23 disposed on the inner peripheral side of the boss portion 6a, and slip rings 19 and 20 on which the brushes 22 and 23 slide against each other. The electromagnetic coil 2 is energized through the energization mechanism, and the brushes 22 and 23 and the slip rings 19 and 20 are maintained in mutual contact by magnetic force.

  As described above, in the conventional coil rotation type clutch, the state in which the brushes 22 and 23 are pressed against the slip rings 19 and 20 by the spring force of the coil springs 25 and 26, respectively, is maintained. The electromagnetic coil 2 can be energized through the brushes 22 and 23 and the slip rings 19 and 20. However, when only the spring force of the coil springs 25 and 26 is used, the brushes 22 and 23 may jump due to the compression vibration of the compressor 5 or the actual vehicle vibration of the vehicle on which the electromagnetic clutch 40 is mounted. There is. When the brush jumps, the contact between the brushes 22 and 23 and the slip rings 19 and 20 cannot be maintained, and there is a possibility that the energization of the electromagnetic coil 2 is cut off, a spark is generated, or the brush tip is damaged.

  With respect to such a problem, in the electromagnetic clutch 40 according to the first embodiment, the brushes 22 and 23 as the sliding energization mechanism and the slip rings 19 and 20 are configured to maintain mutual contact by magnetic force. . With this configuration, in addition to the pressure contact by the spring force (axial force) of the conventional coil springs 25 and 26, the brushes 22 and 23 and the slip rings 19 and 20 are attracted to each other by a magnetic force. The contact state with the slip rings 19 and 20 can be further strengthened, and the splashing of the brushes 22 and 23 due to the compression vibration of the compressor 5 or the actual vehicle vibration can be suitably prevented. As a result, the electromagnetic clutch 40 according to the first embodiment can reliably contact the slip rings 19 and 20 and the brushes 22 and 23, and can improve energization reliability.

  Further, in the electromagnetic clutch 40 according to the first embodiment, as a specific method for generating magnetic force, the brushes 22 and 23 are formed by mixing magnetic powder, and the brushes 22 and 23 generate magnetic force by the magnetic powder. The contact between the brushes 22 and 23 and the slip rings 19 and 20 is maintained. With this configuration, the slip rings 19 and 20 can be attracted to the brushes 22 and 23 by the magnetic force generated by the brushes 22 and 23, and the contact state between the brushes 22 and 23 and the slip rings 19 and 20 is further strengthened. be able to.

[Second Embodiment]
A second embodiment will be described with reference to FIGS. The electromagnetic clutch 40A according to the second embodiment is different from the electromagnetic clutch 40 according to the first embodiment in a method of generating a magnetic force between the brushes 22A and 23A as the sliding energization mechanism and the slip rings 19 and 20.

  Specifically, in the electromagnetic clutch 40A of the second embodiment, the brushes 22A and 23A are configured to include a magnetic member 31 that extends over the entire length in the axial direction and is exposed at the end in the axial direction. The For example, as shown in FIG. 5, the magnetic member 31 is formed of a ferrous metal (ferromagnetic material) having a circular cross-sectional shape, but the cross-sectional shape may be other than a circular shape. The brushes 22A and 23A can be molded by pressing and solidifying the magnetic member 31 in, for example, copper powder.

Then, in the second embodiment, when the armature 8 is attracted to the drive-side rotor 1, the leakage flux M _L transmitted from the armature 8 to the slip rings 19 and 20, the magnetic member 31 (and the brush 22A, 23A) is By being sucked by the slip rings 19 and 20, the contact between the brushes 22A and 23A and the slip rings 19 and 20 is maintained.

In the second embodiment, the leakage magnetic flux M _L from the magnetic circuit M must flow to slip rings 19, 20 through the slip ring holding member 18. Therefore, the slip ring holding member 18 is formed of an iron-based metal (ferromagnetic material) as with each element constituting the magnetic circuit M.

  The electromagnetic clutch 40A according to the second embodiment has the magnetic member 31 and the brushes 22A and 23A including the magnetic member 31 by the magnetic force generated by the slip rings 19 and 20 by the magnetic force generation method described above. It can be made to adsorb | suck to the slip rings 19 and 20, and the contact state of brush 22A, 23A and the slip rings 19, 20 can be made still stronger.

  Furthermore, in the electromagnetic clutch 40 </ b> A according to the second embodiment, a force for pressing the brushes 22 </ b> A and 23 </ b> A against the slip rings 19 and 20 is obtained using leakage of magnetic flux that attracts the armature 8. For this reason, compared with the conventional method using only the pressure contact by the coil springs 25 and 26, the brush 22A by the leakage magnetic flux ML is used only at the time of clutch-on where there is a fear of spark (that is, when compression vibration is generated by the compressor 5). A pressing force of 23A is supported. Thereby, the pressing force by the coil springs 25 and 26 when the clutch is off can be reduced, and the amount of wear of the brushes 22A and 23A can be reduced.

  In the electromagnetic clutch 40A according to the second embodiment, as shown in FIG. 5, the magnetic member 31 is disposed at the center of gravity of the brushes 22A and 23A on the end faces in the axial direction of the brushes 22A and 23A. With this configuration, the brushes 22A and 23A can be easily adsorbed to the slip rings 19 and 20, and the brushes 22A and 23A can be hardly detached from the slip rings 19 and 20 due to sliding or vibration of the brushes 22A and 23A. Thereby, the slip rings 19 and 20 and the brushes 22A and 23A can be more reliably brought into contact with each other.

  In addition, the electromagnetic clutch 40A according to the second embodiment is common to the first embodiment in that the brushes 22A and 23A and the slip rings 19 and 20 are configured to maintain mutual contact by magnetic force. An effect similar to that of the electromagnetic clutch 40 of the embodiment can be obtained.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. For example, the elements included in each of the specific examples described above and their arrangement, materials, conditions, shapes, sizes, and the like are not limited to those illustrated, and can be changed as appropriate. Moreover, each element with which each embodiment mentioned above is provided can be combined as long as technically possible, and the combination of these is also included in the scope of the present invention as long as it includes the features of the present invention.

1: Driving rotor (rotating member)
2: Electromagnetic coil 5: Compressor (rotary machine)
6: Housing 6a: Boss portion 8: Armature 13: Rotating shaft 19, 20: Slip rings 22, 23, 22A, 23A: Brush 31: Magnetic body member 40, 40A: Electromagnetic clutch

Claims (4)

It is applied to a rotating machine (5) provided with a boss portion (6a) protruding in a cylindrical shape outward in the axial direction in the housing (6) and having a rotating shaft (13) disposed at the center of the boss portion, An electromagnetic clutch (40, 40A) for intermittently transmitting rotation to the rotating shaft,
A rotating member (1);
An electromagnetic coil (2) that is arranged to be electrically insulated from the rotating member and generates an electromagnetic attractive force when energized;
An armature (8) disposed opposite to the rotating member and attracted to the rotating member by an electromagnetic attractive force generated by the electromagnetic coil,
The rotation member is configured to transmit rotation to the rotation shaft via the rotation member and the armature by adsorbing the armature to the rotation member.
A sliding energization mechanism including a brush (22, 23, 22A, 23A) disposed on an inner peripheral side of the boss portion and a slip ring (19, 20) on which the brush slides in pressure contact; Configured to energize the electromagnetic coil through a dynamic energization mechanism,
The brush and the slip ring are kept in mutual contact by magnetic force;
Electromagnetic clutch. The brushes (22, 23) are formed by mixing magnet powder,
Contact between the brush and the slip ring is maintained by the magnetic force generated by the magnetic powder generated by the brush.
The electromagnetic clutch (40) according to claim 1. The brush (22A, 23A) includes a magnetic member (31) that extends over the entire length in the axial direction and is exposed at the end in the axial direction.
When the armature to the rotary member is attracted, the by leakage flux transmitted to the slip ring (M _L) from the armature, the contact of said magnetic member is attracted to the slip ring and the brush and the slip ring Is maintained,
The electromagnetic clutch (40A) according to claim 1. On the end face in the axial direction of the brush, the magnetic member is disposed at the center of gravity of the brush.
The electromagnetic clutch according to claim 3.

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