JP5221431B2 - Electromagnetic clutch and manufacturing method thereof - Google Patents

Description

  The present invention relates to an electromagnetic clutch that transmits power to a compressor for a car air conditioner or a water pump, and a manufacturing method thereof.

  Electromagnetic clutches used in car air conditioner compressors, water pumps, etc. are generally composed of non-excitation operation type electromagnetic clutches, and when the excitation coil is not excited, the armature is magnetically attracted to the rotor by the magnetic force of the permanent magnet. Thus, the power of the engine is transmitted to the driven device, and the armature is released from the permanent magnet by canceling the magnetic force by the permanent magnet by energizing the exciting coil when the power transmission is interrupted.

  As such a non-excitation operation type electromagnetic clutch, what was indicated by patent documents 1 and 2, for example is known.

  The non-excitation actuating electromagnetic clutch described in Patent Document 1 is arranged on a rotor attached to a rotating shaft, a hub rotatably attached to the rotating shaft, an armature attached to the hub, and the rotor. And a permanent magnet and an exciting coil. The rotor is composed of two members, an outer magnetic pole member and an inner magnetic pole member, which are integrally coupled by a compound made of a nonmagnetic material, and a permanent magnet is interposed in a space formed between the flange portions of these two members. The magnetic circuit of the permanent magnet forms a magnetic circuit in which the magnetic flux bypasses the armature from the outer magnetic pole of the rotor (the magnetic pole surface of the outer magnetic pole member) and passes through the inner magnetic pole of the rotor (the magnetic pole surface of the inner magnetic pole member).

  On the other hand, the magnetic circuit when the exciting coil is energized forms a magnetic circuit in which the magnetic flux passes through the field core through the field core-inner magnetic path member-permanent magnet-outer magnetic path member.

  In the non-excitation actuated electromagnetic clutch having such a structure, in the non-excited state where the energization to the exciting coil is cut off, the frictional surface (polar surface) of the armature is brought into contact with the friction surface (polar surface) of the rotor by the magnetic force generated by the magnetic flux of the permanent magnet By magnetically adsorbing the inner and outer pole surfaces), the rotor and the armature are frictionally coupled, and the rotation of the rotor is transmitted to the hub via the armature. For example, in the case of a water pump electromagnetic clutch that circulates engine coolant, the power of the engine is transmitted to the rotor via the belt, so that the water pump is also driven while the engine is being driven. When the drive of the water pump is stopped during driving of the engine, the armature is released from the permanent magnet by energizing the exciting coil and canceling the magnetic force caused by the magnetic flux of the permanent magnet by the magnetic force caused by the magnetic flux of the exciting coil. As a result, the armature is separated from the rotor, the power transmission from the engine to the water pump is interrupted, and the water pump stops.

  The electromagnetic clutch described in Patent Document 2 has an inner cylindrical magnetic path portion (inner magnetic flux path portion) in which a bearing fitting portion is formed on the inner peripheral surface of the rotor, and a pulley groove formed on the outer peripheral surface. Consists of an outer cylindrical magnetic path section (outer magnetic flux path section) and a disk-shaped magnetic path section (flange section) that connects one end of both magnetic path sections. doing. The magnetic body is configured by integrally coupling a pair of annular magnetic plates and an annular permanent magnet.

  The permanent magnet is opposed to the outer cylindrical magnetic path portion and the inner cylindrical magnetic path portion of the rotor with an appropriate gap, and is sandwiched between a pair of annular magnetic plates. Of the pair of annular magnetic plates, one annular magnetic plate located on the inner side of the rotor from the permanent magnet has an appropriate gap between the inner surface of the disk-shaped magnetic path portion and the inner peripheral surface of the outer cylindrical magnetic path portion. It is kept opposite and fixed to the outer peripheral surface of the inner cylindrical magnetic path portion. The other annular magnetic plate faces the inner cylindrical magnetic path portion and the exciting coil with an appropriate gap, and is fixed to the inner peripheral surface of the outer cylindrical magnetic path portion. Note that this electromagnetic clutch employs a double flux system, and the operation is exactly the same, although it is different from the single flux system electromagnetic clutch described in Cited Document 1.

U.S. Pat. No. 3,263,784 Japanese Utility Model Publication No. 63-011394

  However, the conventional electromagnetic clutch described in Patent Document 1 described above includes a rotor, an inner magnetic pole member, and an outer peripheral surface of the permanent magnet and an inner peripheral surface of the outer magnetic pole member, and an inner portion of the permanent magnet. Electromagnetic clutch with low productivity because it employs a permanent magnet built-in rotor structure in which a compound is filled between the outer peripheral surface and the outer peripheral surface of the inner magnetic pole member, and the inner magnetic pole member is integrally coupled. There was a problem that could not be provided at low cost.

  The electromagnetic clutch described in Patent Document 2 is easy to manufacture and assemble because it uses an integral rotor, but because it is a double flux system, it faces one annular magnetic plate of the magnetic body and the armature. It is necessary to provide a gap between the rotor and the disk-shaped magnetic path. For this reason, there existed a problem that the dimension of the axial direction of an electromagnetic clutch became large. For example, it is necessary to change the design of the cylindrical part of the front housing of the compressor (the part where the bearing for rotatably supporting the rotor is fitted) and the size of the rotating shaft whose tip protrudes from this cylindrical part. Lack. In addition, since the annular permanent magnet formed integrally is expensive, there is a problem that the manufacturing cost of the electromagnetic clutch cannot be reduced. Furthermore, when the rotor is immersed in the cationic electrodeposition paint for electrodeposition coating, it is in the gap between the disk-shaped magnetic path portion of the rotor and the annular magnetic plate, and between the annular magnetic plate and the field core. When air accumulates, poor electrodeposition occurs, and when the paint remains as a liquid pool, poor appearance occurs.

  Therefore, in order to solve such a problem, it is also conceivable to assemble parts after subjecting them to surface treatment in advance. However, in that case, when fixing a magnetic body consisting of a surface-treated annular magnetic plate and permanent magnet to the inside of the rotor by caulking, electron beam welding, laser welding, etc., the appearance will be poor if it is accidentally damaged during the work. Is not practical.

  The present invention has been made to solve the above-described conventional problems, and an object of the present invention is to provide an electromagnetic clutch capable of improving the assembly workability and reducing the manufacturing cost.

  In order to achieve the above object, the present invention comprises an inner cylindrical magnetic path portion, an outer cylindrical magnetic path portion, and a disk-shaped magnetic path portion that connects one end of both magnetic path portions, and a driven device. A rotor rotatably disposed in the housing, an armature hub attached to a rotating shaft of the driven device, and an armature hub movably disposed in an axial direction so as to contact and separate the armature hub and the rotor. An armature that can be connected, a magnet unit that is disposed inside the rotor and magnetically attracts the armature to the magnetic pole surface of the rotor, and a magnet unit made of a magnetic material and a permanent magnet; A field core inserted by contact and facing the magnetic body, and disposed in the field core to cancel the magnetic force of the permanent magnet during excitation, And an exciting coil for releasing the permanent magnet from the permanent magnet, the permanent magnet is composed of a plurality of magnet pieces, the magnet pieces are temporarily fixed in a ring shape to the magnetic body by temporary fixing members, and the magnetic body is attached to the rotor The magnet piece is in close contact with the inner surface of the disk-shaped magnetic path portion.

  Further, the present invention is the above invention, wherein the magnetic body is provided with an annular recess into which a magnet piece is fitted, the magnet piece is formed in an arc shape, the temporary fixing member has elasticity, and the gap between the magnet pieces is By interposing, the outer periphery of each magnet piece is pressed against the inner wall of the annular recess.

  Further, the present invention is the above invention, wherein the temporary fixing member is formed in a disc shape and has a plurality of attachment portions into which magnet pieces are fitted.

  In the present invention, the magnet unit is magnetized after the magnet unit is incorporated in the rotor.

  In the present invention according to the present invention, the magnetic body has a center hole and a discharge opening for discharging air or a solution.

  Furthermore, the present invention includes a step of temporarily fixing a plurality of magnet pieces before magnetization to a magnet mounting surface of a magnetic body by a temporary fixing member and assembling a magnet unit; and incorporating the magnet unit into a rotor; The method includes a step of fixing the magnet piece to the rotor, a step of immersing the rotor in a processing solution to perform a surface treatment, and a step of magnetizing the magnet piece.

In the present invention, since the permanent magnet is composed of a plurality of magnet pieces, it is not necessary to use an expensive permanent magnet integrally formed, and the manufacturing cost can be reduced.
In addition, the magnet unit is built into the rotor with the magnet piece temporarily fixed to the magnetic body by the temporary fixing member, and then the magnetic body is fixed to the rotor and the magnet piece is magnetized. Assembly is easy, and productivity can be improved.
In addition, since the temporary fixing member having elasticity can be formed of a wire spring, synthetic resin, metal plate, etc., it is inexpensive and easy to manufacture, and is securely fixed temporarily by pressing the magnet piece against the inner wall of the magnetic body. can do.
In addition, since the discharge opening is provided in the magnetic material, when the rotor is dipped in a treatment liquid such as plating or cationic electrodeposition coating and surface-treated, the air in the space behind the rotor magnet unit or The processing liquid can be reliably discharged from the discharge opening to the outside of the rotor. Accordingly, it is possible to prevent coating defects due to air and appearance defects due to the processing liquid.

It is a top view of the non-excitation state which shows one Embodiment of the electromagnetic clutch which concerns on this invention. It is the sectional view on the AA line of FIG. It is a top view of a rotor. It is a rear view of a rotor. (A) is a top view of a magnet unit, (b) is a BB sectional drawing. It is sectional drawing of the excitation state of an electromagnetic clutch. (A) is a top view which shows other embodiment of a magnet unit, (b) is CC sectional view taken on the line. (A) is a top view which shows other embodiment of a magnet unit, (b) is DD sectional view taken on the line. (A) is a top view which shows other embodiment of a magnet unit, (b) is EE sectional view taken on the line. (A) is a top view which shows other embodiment of a magnet unit, (b) is FF sectional view taken on the line. It is sectional drawing which shows other embodiment of the electromagnetic clutch of this invention.

  1 to 6, the present embodiment transmits the rotation of an engine (not shown) as a driving side device to the rotating shaft 3 of the car air conditioner compressor 2 as a driven side device, or interrupts the transmission. The example applied to the single-flux type electromagnetic clutch 1 is shown. The electromagnetic clutch 1 is disposed in a rotor 6 rotatably disposed in a housing 4 of a car air conditioner compressor 2 via a bearing 5, an armature assembly 7 fixed to the rotating shaft 3, and the rotor 6. The magnet unit 8 and the electromagnetic coil device 9 are provided.

  The rotor 6 is generally made of a material such as mechanical structural carbon steel (S12C) or hot rolled steel (SPHC) into a double cylindrical shape having one end opened by hot forging or cold forging. Thus, a concentric inner cylindrical magnetic path portion 6A and an outer cylindrical magnetic path portion 6B, and a disk-shaped magnetic path portion 6C for connecting the armature side ends of both magnetic path portions 6A and 6B to each other are integrally provided. The inner cylindrical magnetic path portion 6 </ b> A is rotatably supported by the bearing 5. On the inner peripheral surface 6a of the inner cylindrical magnetic path portion 6A, a step portion 12 is formed that is formed of an annular groove into which the outer ring of the bearing 5 is fitted. On the other hand, a plurality of V-shaped grooves 13 are formed on the outer peripheral surface of the outer cylindrical magnetic path portion 6B, and the power of the automobile engine is passed through these V-shaped grooves 13 via a V-belt (not shown). Communicated.

  The space inside the rotor 6, that is, the space surrounded by the inner cylindrical magnetic path portion 6 </ b> A, the outer cylindrical magnetic path portion 6 </ b> B, and the disc-shaped magnetic path portion 6 </ b> C forms an annular groove 14 that opens to the housing 4 side. The magnet unit 8 and the electromagnetic coil device 9 are disposed in the annular groove 14.

Discoid magnetic path portion 6C of the rotor 6, the surface forms a pole face 15 which magnetically attracted armature 16, a disc-shaped magnetic path of the magnetic flux phi ₁ of the permanent magnet 17 constituting the magnet unit 8 to near the outer periphery A plurality of through holes 18 for bypassing the magnetic flux to be bypassed from the portion 6C to the armature 16 are formed. As shown in FIG. 3, the through holes 18 are arc-shaped long holes formed concentrically, and communicate with the annular grooves 14. That is, the electromagnetic clutch 1 in the present embodiment constitutes a single flux type electromagnetic clutch by a plurality of through holes 18 arranged and formed on the same circumference.

  The armature assembly 7 includes the armature 16, an armature hub 20, a leaf spring 21 as an armature support, and the like.

  The armature 16 is formed in a disk shape from a magnetic material, and is supported on the armature hub 20 by a leaf spring 21 so as to be movable in the axial direction. A surface of the armature 16 facing the magnetic pole surface 15 of the rotor 6 forms a friction surface 16a.

  The armature hub 20 is composed of a boss portion 20A and a disk-like flange 20B integrally projecting on the outer periphery of the boss portion 20A. The boss portion 20A is splined to the end portion 3A of the rotary shaft 3. And fixed by a nut 22.

  The leaf spring 21 is formed of a fixed base portion 21A and a free end portion 21B by forming a rectangular shape by punching a spring steel plate or the like (FIG. 1), and the fixed base portion 21A is a flange of the armature hub 20. It is in close contact with the back surface of the portion 20B and fixed by caulking with a plurality of rivets 23. The free end portion 21 </ b> B is brought into close contact with a plane opposite to the friction surface 16 a of the armature 16 and fixed by caulking with a plurality of rivets 24. Further, the leaf spring 21 has a connecting portion between the fixed base portion 21A and the free end portion 21B that is elastically deformable in the plate thickness direction, and the free end portion 21B is further forward than the fixed base portion 21A in the rotational direction of the armature hub 20. And is bent at a required angle on the rotor 6 side.

  In FIG. 5, the magnet unit 8 includes a permanent magnet 17 and a temporary fixing member 31 that temporarily fixes the magnetic body 30 and the permanent magnet 17 to the magnetic body 30. Although the permanent magnet 17 has a ring shape, the permanent magnet 17 includes, for example, eight arc-shaped magnet pieces 17a to 17h divided in the circumferential direction.

  The pole pieces 17a to 17h are made of a ferromagnetic material such as neodymium or ferrite, and N and S poles are magnetized on the front and back surfaces. However, the magnet pieces 17 a to 17 h are magnetized after being incorporated in the rotor 6 together with the magnetic body 30.

  The magnetic body 30 has a center hole 32 larger than the outer diameter of the inner cylindrical magnetic path portion 6A of the rotor 6, and is formed in a disc shape whose outer diameter is substantially equal to the inner diameter of the outer cylindrical magnetic path portion 6B. Yes. The surface on the armature 16 side of the magnetic body 30 forms a magnet attachment surface 30a to which the permanent magnet 17 is attached, and has an annular recess 33 into which the permanent magnet 17 is fitted. The annular recess 33 has a hole diameter substantially equal to the outer diameter of the permanent magnet 17, in other words, the outer diameter of the magnet pieces 17a to 17h, and the outer circumference of the permanent magnet 17 is in close contact with the inner wall 33A. The magnetic body 30 has a plurality of discharge openings 34 formed therein. The discharge opening 34 is for improving the discharge of the air and the processing liquid accumulated in the rotor 6 during the surface treatment such as plating or painting of the rotor 6. In this embodiment, the outer periphery of the magnetic body 30 is used. Although the example of the semicircular notch formed in the above is shown, the present invention is not limited to this, and a through hole having an appropriate shape may be used. If such a discharge opening 34 is provided, in the state where the magnet unit 8 is incorporated in the annular groove 14 of the rotor 6, the space 36 </ b> A on the back side and the space 36 </ b> B on the near side from the magnet unit 8 of the annular groove 14 ( 2) can be communicated with each other by the discharge opening 34, so that it is possible to prevent air and processing liquid from accumulating in the inner space 36A in the post-processing step.

  In FIG. 5, the temporary fixing member 31 is for temporarily fixing the magnetized pieces 17 a to 17 h to the magnetic body 30 before the magnet unit 8 is assembled in the rotor 6. The elastic deformation portions 31A and 31B facing each other and the connecting portion 31C connecting the base ends of the elastic deformation portions 31A and 31B are formed by being formed in a substantially U shape or Ω shape by synthetic resin or the like. The elastically deforming portions 31A and 31B are respectively provided with locking portions 31D and 31E that are bent outward at the free ends. As shown in FIG. 5 (a), such a temporary fixing member 31 is configured such that the magnet pieces 17 a to 17 h are arranged in a ring shape while maintaining a gap 38 in the circumferential direction in the annular recess 33 of the magnetic body 30. Elastically deforming portions 31A and 31B are closed with the legs closed, whereby the elastically deforming portions 31A and 31B are elastically restored to press the side surfaces of the magnet pieces 17a to 17h, and the locking portions 31D and 31E are The magnet pieces 17a to 17h are pressed against the magnetic body 30 by pressing the inner peripheral corners of the magnet pieces 17a to 17h and pressing the outer peripheral surfaces of the magnet pieces 17a to 17h against the inner wall 33A of the annular body 30. Temporarily fixed. The magnet unit 8 is incorporated in the rotor 6 with the magnetic pole pieces 17 a to 17 h temporarily fixed to the magnetic body 30. In assembling, the magnetic body 30 is press-fitted into the annular groove 14 of the rotor 6 and the magnet pieces 17a to 17h are pressed against the inner surface of the disk-shaped magnetic path portion 6C, and the magnetic body 30 is pressed against the inner surface of the outer cylindrical magnetic path portion 6B. Fix it. The magnetic body 30 can be fixed to the outer cylindrical magnetic path portion 6B by caulking, electronic beer welding, laser welding, or the like. FIG. 2 shows an example of fixing by caulking, and the symbol K is the caulking portion of the outer cylindrical magnetic path portion 6B.

  The temporary fixing method and temporary fixing member of the magnet pieces 17a to 17h are not limited to the above-described embodiment, and various changes and modifications can be made as shown in FIGS. 7 to 10, for example.

  FIG. 7 shows an example in which every two magnet pieces 17a to 17h are arranged in a ring shape with an interval 38a therebetween, and a temporary fixing member 39 formed in a substantially U shape is elastically mounted in each gap 38a. It is shown. The temporary fixing member 39 is different in that the interval between the two elastically deforming portions 39A and 39B is set larger than the interval between the elastically deforming portions 31A and 31B of the temporary fixing member 31 shown in FIG. Are all the same.

  FIG. 8 shows two temporary fixings having a plurality of convex portions 41 in which the magnet pieces 17a to 17h are arranged in a ring shape with an interval 38 as in FIG. 5 and two wire springs are bent into an arc shape. An example of temporary fixing with the member 40 is shown. The convex portion 41 of the temporary fixing member 40 has the same shape and function as the temporary fixing member 31 shown in FIG.

  9 has a plurality of convex portions 43 in which magnet pieces 17a to 17h are arranged in a ring shape with an interval 38a between every two magnet pieces 17a to 17h, and one wire spring is bent into a ring shape. An example of temporary fixing by the temporary fixing member 42 is shown. The convex portion 43 of the temporary fixing member 42 has the same shape and function as the temporary fixing member 39 shown in FIG.

  In FIG. 10, the temporary fixing member 44 is formed of a disk, and a plurality of attachment portions 45 to which the magnet pieces 17 a to 17 h are fitted are provided at equal intervals in the circumferential direction. The mounting portion 45 is formed of an arc-shaped through hole, and has rising walls 46a and 46b on the outer peripheral edge and the inner peripheral edge, and the outer peripheral surfaces and inner peripheral surfaces of the magnet pieces 17a to 17h are sandwiched by these rising walls. I have to. For this reason, the interval between the rising walls 46 a and 46 b is set slightly narrower than the width of the magnet pieces 17 a to 17 h, and the magnet pieces 17 a to 17 h are press-fitted into the mounting portions 45 from the back surface side of the temporary fixing member 44. In addition, the both ends of the attaching part 45 comprise the opening part 34 for discharge | emission by setting wider than the width | variety of the magnet pieces 17a-17h.

  In FIG. 2, the electromagnetic coil device 9 includes an exciting coil 50 and a field core 51. The field core 51 integrally includes an inner cylindrical portion 51A and an outer cylindrical portion 51B that are concentrically formed, and a disc portion 51C that connects ends of both the cylindrical portions 51A and 51B opposite to the armature 16 side. Thus, it consists of a double cylindrical body similar to the rotor 6, and the disc portion 51 </ b> C is fixed to the housing 4 via the mounting plate 52, and in other words, a slight gap is maintained in the annular groove 14 of the rotor 6. The rotor 6 is loosely inserted in a non-contact state, and faces the magnetic body 30 of the magnet unit 8 with an appropriate gap. The exciting coil 50 is housed in the interior 53 of the field core 51 and molded with a synthetic resin 54.

  When manufacturing such an electromagnetic clutch 1, a plurality of magnet pieces 17a to 17h and a magnetic body 30 are prepared. Then, the magnet pieces 17 a to 17 h are temporarily fixed to the annular recess 33 of the magnetic body 30 by the temporary fixing member 31, and the magnet unit 8 is assembled. In this state, since the magnet pieces 17a to 17h are not yet magnetized, the magnet pieces 17a to 17h and the magnetic plate 30 are not magnetically attracted.

  Next, the magnet unit 8 is assembled into the rotor 6, and the magnet pieces 17 a to 17 h are pressed against the inner surface of the disc-shaped magnetic path portion 6 </ b> C of the rotor 6. Then, the magnetic body 30 is caulked to the inner peripheral surface of the outer cylindrical magnetic path portion 6 and fixed by electron beam welding or the like.

  After the assembly operation of the magnet unit 8 to the rotor 6 is completed, the rotor 6 is subjected to a surface treatment such as plating or painting. For example, when applying cationic electrodeposition coating, the rotor 6 is immersed in a cationic electrodeposition coating liquid in an electrodeposition tank, the rotor 6 is used as a cathode, and a voltage is applied between the rotor 6 and the entire rotor 6. A cationic electrodeposition coating film is formed on.

  Here, when the rotor 6 is immersed in the cationic electrodeposition coating liquid, if there is a portion where air remains or the coating liquid accumulates in the rotor 6, it causes a coating failure. Of the space 36 </ b> A on the back side of the magnetic body 30, the portion outside the outer periphery of the permanent magnet 17 in particular is a place where a reservoir for air or paint liquid is easily formed. Therefore, in the present invention, the space 36A on the back side and the space 36B on the near side from the magnetic body 30 are communicated with each other by the discharge opening 34 provided on the outer periphery of the magnetic body 30, so that the air in the back side space 36A In addition, the coating liquid can be reliably discharged to the outside of the rotor 6 through the near space 36B, and the above problem can be solved.

  In addition, since the magnet unit 8 is surface-treated after being incorporated into the rotor 6, there is no possibility that the magnet unit 8 is accidentally damaged when incorporated into the rotor 6 to cause poor appearance.

  When the electrodeposition coating is completed, the rotor 6 is lifted from the electrodeposition tank and heated in a heating furnace to bake a cationic electrodeposition coating film.

  When the electrodeposition coating is completed, the magnet pieces 17a to 17h are magnetized. Magnetization of the magnet pieces 17a to 17h can be magnetized from the outside of the rotor 6 by a magnetizing device.

  After the magnetizing work for the magnet pieces 17a to 17h is completed, the bearing 5 is press-fitted into the rotor 6 to complete the manufacture and assembly of the rotor 6.

  Next, the rotor 6 and the armature assembly 7 are mounted on the compressor 2, and the electromagnetic coil device 9 is inserted and disposed inside the rotor 6, thereby completing the operation of attaching the electromagnetic clutch 1 to the compressor 2.

The electromagnetic clutch 1 having such a structure is generated by the magnetic flux φ ₁ of the permanent magnet 17 in the power transmission state (clutch ON state) shown in FIG. 1, that is, in the non-excitation state in which the energization to the excitation coil 50 is cut off. The armature 16 is magnetically attracted to the magnetic pole face 15 of the rotor 6 by the magnetic force to transmit the engine power to the rotating shaft 3 of the compressor 2 via the rotor 6 and the armature assembly 7. In this power transmission state, the connecting portion between the fixed base portion 21A and the free end portion 21B of the leaf spring 21 is elastically deformed toward the rotor 6 side.

When interrupting the power transmission, the exciting coil 50 is energized so that a magnetic flux φ _{2 in the} direction opposite to the magnetic flux φ ₁ of the permanent magnet 17 is generated. When the exciting coil 50 is excited by energization, the magnetic flux φ ₂ of the exciting coil 50 is, as shown in FIG. 6, the outer cylindrical portion 51B of the field core 51—the outer cylindrical magnetic path portion 6B of the rotor 6—the disc-shaped magnetic path portion. 6C—the armature 16—the disk-shaped magnetic path portion 6C of the rotor 6—the inner cylindrical magnetic path portion 6A—the inner cylindrical portion 51A of the field core 51 and the disk portion 51C. At this time, to excite the exciting coil 50 such that the direction of the magnetic flux phi ₂ is in the opposite direction to the direction of the magnetic flux phi ₁ by the permanent magnet 17, and is substantially the same magnetic force and the magnetic force generated by the magnetic flux phi ₁ of the permanent magnet 17 Thus, the magnetic force caused by the magnetic flux φ ₁ is canceled out by the magnetic force caused by the magnetic flux φ ₂ . For this reason, the armature 16 is released from the magnetic force due to the magnetic flux φ ₁ of the permanent magnet 17, and is separated from the magnetic pole surface 15 of the rotor 6 by the elastic return force of the leaf spring 21, whereby the power transmission to the compressor 2 by the electromagnetic clutch 1 is performed. Blocked. At this time, the armature 16 is separated from the magnetic pole surface 15 of the rotor 6 until the stopper portion 16 </ b> A (FIG. 6) contacts the rivet 23 due to the elastic restoring force of the leaf spring 21. FIG. 6 shows this state. The stopper portion 16 </ b> A is formed to extend radially inward at three locations in the circumferential direction of the inner peripheral surface of the armature 16.

When the power transmission to the compressor 2 is interrupted and then returned to the power transmission state, the energization to the exciting coil 50 is interrupted, and the rotor 6 and the armature 16 are frictionally coupled by the magnetic force generated by the magnetic flux φ ₁ of the permanent magnet 17. Alternatively, the exciting coil 50 is energized in the opposite direction to the opposite direction to generate a magnetic flux in the same direction as the magnetic flux φ ₁ of the permanent magnet 17. As a result, the armature 16 is again magnetically attracted to the magnetic pole surface 15 of the rotor 6 by the magnetic force generated by the magnetic flux of the permanent magnet 17 and the exciting coil 50, and the rotation of the rotor 6 is transmitted to the rotating shaft 3 of the compressor 2. That is, the electromagnetic clutch 1 operates. Then, after the armature 16 is magnetically attracted to the magnetic pole surface 15 of the rotor 6, the energization to the exciting coil 50 is cut off.

  Here, in the electromagnetic clutch 1 according to the present invention, the permanent magnet 17 constituting the magnet unit 8 is constituted by a plurality of magnet pieces 17 a to 17 h, and these magnet pieces 17 a to 17 h are temporarily fixed to the annular recess 33 of the magnetic body 30. Since the magnet unit 8 is temporarily fixed by the member 31 and the magnet unit 8 is assembled in the rotor 6 and the magnetic body 30 is fixed to the rotor 6 in this state, the assembly work of the magnet unit 8 is facilitated. Can be improved. Moreover, since the permanent magnet 17 is comprised by several magnet piece 17a-17h, it is not necessary to use the expensive permanent magnet formed integrally, and the manufacturing cost of an electromagnetic clutch can be reduced. Further, since the discharge opening 34 is provided in the magnetic body 30, when surface treatment such as plating or electrodeposition coating is performed, air or a solution remains in the rotor 6, resulting in poor coating or poor appearance. Therefore, a good surface treatment can be performed.

FIG. 11 is a sectional view of an electromagnetic clutch showing another embodiment of the present invention.
This embodiment is applied to a double flux type electromagnetic clutch 100. For this reason, two large and small magnetic flux bypassing through holes 18A and 18B having different diameters are formed concentrically in the disk-like magnetic path portion 6C of the rotor 6, and the magnetic arm bypassing through hole 101 is also formed in the armature 16. The magnetic holes φ ₁ and φ ₂ of the permanent magnet 17 and the exciting coil 50 are caused to bypass the armature 16 twice by these through holes 18A, 18B, and 101. The through holes 18A, 18b, and 101 are each formed of a plurality of arc-shaped elongated holes, like the through hole 18 shown in FIG. Since other structures are the same as those of the above-described embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted.
Such an electromagnetic clutch 100 can also obtain the same effect as the electromagnetic clutch 1 described above.

  In the above-described embodiments, the armature 16 is attached to the armature hub 20 via the leaf spring 21. However, the present invention is not limited to this example. Alternatively, a rigid plate may be attached to the armature hub 20, and the armature 16 may be attached to the plate via a damper rubber, or the armature 16 may be attached to the armature hub 20 via a coil spring.

  DESCRIPTION OF SYMBOLS 1 ... Electromagnetic clutch, 2 ... Compressor, 3 ... Rotating shaft, 4 ... Housing, 6 ... Rotor, 6A ... Inner cylindrical magnetic path part, 6B ... Outer cylindrical magnetic path part, 6C ... Disc-shaped magnetic path part, 7 DESCRIPTION OF SYMBOLS ... Armature assembly, 8 ... Magnet unit, 9 ... Electromagnetic coil device, 15 ... Magnetic pole surface, 16 ... Armature, 17 ... Permanent magnet, 17a-17h ... Magnet piece, 20 ... Armature hub, 21 ... Leaf spring, 30 ... Magnetic Body 31 ... Temporary fixing member 32 ... Center hole 30a ... Magnet mounting surface 33 ... Annular recess 33A ... Inner wall 34 ... Discharge opening 44 ... Temporary fixing member 45 ... Mounting portion 50 ... Excitation coil 51. Field core.

Claims (4)

A rotor that is composed of an inner cylindrical magnetic path portion, an outer cylindrical magnetic path portion, and a disk-shaped magnetic path portion that connects one end of both magnetic path portions, and is rotatably disposed in the housing of the driven device. When,
An armature hub attached to the rotating shaft of the driven device;
An armature that is disposed on the armature hub so as to be movable in an axial direction and connects the armature hub and the rotor in a detachable manner;
A magnet unit made of a magnetic material and a permanent magnet that is disposed inside the rotor and magnetically attracts the armature to the magnetic pole surface of the rotor;
A field core attached to the housing and inserted into the rotor in a non-contact manner and facing the magnetic body;
An excitation coil disposed within the field core to cancel the magnetic force of the permanent magnet during excitation and release the armature from the permanent magnet;
The permanent magnet is composed of a plurality of magnet pieces, the magnet pieces are temporarily fixed in a ring shape to the magnetic body by a temporary fixing member, the magnetic body is fixed inside the rotor, and the magnet pieces are attached to the disk. Close to the inner surface of the magnetic path,
The magnet unit is an electromagnetic clutch in which the plurality of magnet pieces are magnetized after being incorporated into the rotor. The electromagnetic clutch according to claim 1,
The magnetic body has an annular recess into which a magnet piece is fitted,
The magnet piece is formed in an arc shape,
The temporary fixing member is an electromagnetic clutch which has elasticity and presses the outer periphery of each magnet piece against the inner wall of the annular recess by being interposed between the magnet pieces. The electromagnetic clutch according to claim 1,
The temporary fixing member is an electromagnetic clutch that is formed in a disc shape and has a plurality of attachment portions into which magnet pieces are fitted. The electromagnetic clutch according to any one of claims 1, 2, and 3,
The magnetic body is an electromagnetic clutch having a center hole and a discharge opening for discharging air or a solution.

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