JP2014109375A - Electromagnetic clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact electromagnetic clutch.SOLUTION: An electromagnetic clutch 100 is provided with: a drive pulley 10 having an outside cylindrical part 11, a disk plate part 12, and an inside cylindrical part 13; a field core 20 housed in a circular space 15 surrounded by an inner peripheral surface 11B of the outside cylindrical part 11, an axial direction end surface 12B of the disk plate part 12, and an outer peripheral surface 13A of the inside cylindrical part 13; a rotary shaft 30 of a variable water pump 120 for an automobile engine; an operation member 40 thrust rotatably supported with respect to the rotary shaft 30; an electromagnetic solenoid 50 which is housed in the state that it is supported by the field core 20 and generates a magnetic force which suctions and fixes the operation member 40; a seal member 60 forming a sealed space 61 liquid-tightly sealed up in a gap between the drive pulley 10 and the field core 20; and a magnetic fluid 70 filled up in the sealed space 61.

Description

  The present invention relates to an electromagnetic clutch that intermittently inputs and outputs rotational power to a variable water pump for an automobile engine.

  2. Description of the Related Art Conventionally, an electromagnetic clutch has been used as one of devices that intermittently transmit rotational power from a driving device that is rotationally driven to a driven device that uses the rotational power of the driving device as a power source. There exists a thing of patent document 1 as a technique regarding such an electromagnetic clutch.

  The electromagnetic clutch described in Patent Document 1 includes a rotor that is rotated by a drive-side device, a field core that is supported by the driven-side device and that accommodates an excitation coil, and a rotor that rotates integrally with a rotation shaft of the driven-side device. And an armature configured to be able to contact and separate. In this electromagnetic clutch, when the exciting coil is not energized, the armature and the rotor are separated from each other, so that rotational power is not input to the rotating shaft of the driven device. On the other hand, when the exciting coil is energized, a magnetic path is formed between the armature, the rotor, and the field core, and the armature is attracted to the rotor. Thereby, the rotational power from the drive side device is input to the rotation shaft of the driven side device via the rotor and the armature.

JP 2012-117551 A

  In the technique described in Patent Document 1, a rotor that is rotationally driven by the rotational power of a drive-side device is disposed on the radially outer side of the field core. On the other hand, the field core is supported by a driven device that is in a stationary state regardless of whether the electromagnetic clutch is engaged or not. For this reason, a gap is provided in the circumferential direction between the rotor and the field core so as not to hinder the rotational drive of the rotor. When the armature is attracted to the rotor, it is necessary to form a magnetic path through such a gap at the beginning of the attracting. Since the magnetic resistance of such a gap (the magnetic resistance of air existing in the gap) is much larger than the magnetic resistance of the field core, it is necessary to increase the strength of the magnetic field generated by the exciting coil. As such a method, it is conceivable to increase the number of windings of the exciting coil wire, increase the current to be energized, or increase the cross-sectional area of the field core.

  However, when the number of windings of the exciting coil wire is increased, the size of the exciting coil itself is increased. Further, when increasing the current to be applied to the exciting coil, it is necessary to increase the diameter of the wire in order to reduce the Joule heat generated in the wire of the exciting coil. As a result, the size of the exciting coil is increased. Furthermore, even when the cross-sectional area of the field core is increased, the size of the exciting coil is increased. Such an increase in the size of the exciting coil leads to an increase in the size of the electromagnetic clutch, making it difficult to adopt it for in-vehicle applications where there is a strong demand for weight reduction and size reduction.

  In view of the above problems, an object of the present invention is to provide a small electromagnetic clutch.

  In order to achieve the above object, the electromagnetic clutch according to the present invention is characterized in that an outer cylindrical portion in which a belt winding portion around which a drive belt that rotates synchronously with a crankshaft of an automobile engine is wound is formed on an outer peripheral surface. A disc-like disc-like portion extending radially inward at one of axial end portions of the outer cylindrical portion, and extending in the axial direction from an inner edge portion of the disc-like portion, A driving pulley having an inner cylindrical portion provided opposite to the cylindrical portion; an inner peripheral surface of the outer cylindrical portion; an axial end surface of the disc-shaped portion; and an outer peripheral surface of the inner cylindrical portion. At least a part is accommodated in the enclosed annular space, and is rotated on the same axis as the non-rotating portion of the field core made of a magnetic material and the rotational axis of the drive pulley in response to power from the drive pulley. Supply refrigerant to the engine A rotating shaft of a variable water pump for an automobile engine, supported to be rotatable with respect to the rotating shaft, an operating member made of a magnetic material, and housed in the field core in a state supported by the field core, An electromagnetic solenoid that generates a magnetic force for adsorbing and fixing the operating member; a sealing member that forms a sealed space that is liquid-tightly sealed in at least a part of a gap between the drive pulley and the field core; and the sealing And a magnetic fluid filled in the space.

  With such a characteristic configuration, at least a part of the gap existing between the drive pulley and the field core can be eliminated. For this reason, since the magnetic resistance between the drive pulley and the field core can be reduced, the strength of the magnetic field when electromagnetically attracting the actuating member to the field core is reduced in the case of an electromagnetic clutch having a conventional gap. It can be made smaller. Therefore, the size of the electromagnetic solenoid can be reduced. In accordance with this, since the drive pulley having a small diameter can be used, the electromagnetic clutch can be miniaturized.

  Further, it is preferable that the sealed space is formed between the outer cylindrical portion and the field core and between the inner cylindrical portion and the field core.

  With such a configuration, the magnetic fluid can be filled between the outer cylindrical portion and the field core and between the inner cylindrical portion and the field core. Magnetic resistance can be reduced. For this reason, since the intensity of the magnetic field generated by the electromagnetic solenoid can be reduced, the electromagnetic solenoid can be changed to a compact one. Therefore, the electromagnetic clutch can be reduced in size.

  Further, it is preferable that the field core is an annular core accommodated in the annular space.

  With this configuration, each of the space between the outer cylindrical portion of the drive pulley and the field core and the space between the inner cylindrical portion of the drive pulley and the field core can be configured in an annular shape. it can. Therefore, in the configuration of the sealed space, it is only necessary to use seal members on both sides in the axial direction of the respective annular spaces, so that the magnetic fluid can be easily filled.

It is a sectional side view of an electromagnetic clutch. It is the II-II sectional view taken on the line of FIG. It is a figure which shows the partial cross section figure of an electromagnetic clutch.

  The electromagnetic clutch according to the present invention has a function of transmitting rotational power input to an automotive engine variable water pump 120 that supplies a coolant to an automotive engine, and blocking the rotational power. Hereinafter, the electromagnetic clutch 100 of the present embodiment will be described in detail.

  FIG. 1 shows a side sectional view of an electromagnetic clutch 100 according to this embodiment. 2 shows a cross-sectional view taken along the line II-II in FIG. FIG. 3 shows an enlarged view around the electromagnetic solenoid 50. As shown in FIG. 1, the electromagnetic clutch 100 includes a drive pulley 10, a field core 20, a rotating shaft 30, an operating member 40, an electromagnetic solenoid 50, a seal member 60, and a magnetic fluid 70. Is done.

  The drive pulley 10 includes an outer cylindrical portion 11, a disc-shaped portion 12, and an inner cylindrical portion 13. The outer cylindrical portion 11 is formed in a cylindrical shape. That is, the outer cylindrical portion 11 is formed in a cylindrical shape having a circular cross section perpendicular to the axial direction as shown in FIG. The outer cylindrical portion 11 has a belt winding portion 14 around which a driving belt 111 that rotates synchronously with the crankshaft 110 of the engine E of the automobile is wound on the outer peripheral surface 11A. The engine E is a power source of an automobile on which the electromagnetic clutch 100 is mounted. The drive belt 111 is wound around the pulley groove 112 of the crankshaft 110 of the engine E and the belt winding portion 14 of the drive pulley 10. Thereby, when the crankshaft 110 is rotationally driven, the rotational driving force is transmitted to the outer cylindrical portion 11 via the driving belt 111, and the driving pulley 10 is rotationally driven.

  The disk-shaped part 12 is configured in a so-called donut shape. The disk-shaped part 12 is configured to extend radially inward at one of the axial ends of the outer cylindrical part 11. The disc-like portion 12 is provided such that the outer peripheral surface of the disc-like portion 12 abuts on the inner peripheral surface 11B of the outer cylindrical portion 11. Therefore, the disk-shaped part 12 is provided coaxially with the outer cylindrical part 11.

  The inner cylindrical portion 13 is also formed in a cylindrical shape. That is, as shown in FIG. 2, the inner cylindrical portion 13 is formed in a cylindrical shape having a circular cross section perpendicular to the axial direction. The inner cylindrical portion 13 extends in the axial direction from the inner edge portion 12 </ b> A of the disk-shaped portion 12 and is provided to face the outer cylindrical portion 11. As described above, the disk-shaped part 12 is formed in a donut shape. Accordingly, the inner cylindrical portion 13 is provided along the axial direction from the doughnut-shaped inner edge portion 12A. The axial length of the inner cylindrical portion 13 is preferably formed to be approximately the same as the axial length of the outer cylindrical portion 11.

  The outer cylindrical part 11, the disk-like part 12, and the inner cylindrical part 13 are integrally formed. Such a drive pulley 10 forms an annular space 15 surrounded by the inner peripheral surface 11B of the outer cylindrical portion 11, the axial end surface 12B of the disk-shaped portion 12, and the outer peripheral surface 13A of the inner cylindrical portion 13. To do. As shown in FIG. 1, the annular space 15 has an opening on one side in the axial direction, and is coaxial with the drive pulley 10 and has a U-shaped cross section orthogonal to the circumferential direction.

  At least a part of the field core 20 is accommodated in the annular space 15. In the present embodiment, the field core 20 is composed of an annular core accommodated in the annular space 15 (see FIG. 2). The field core 20 is provided with a gap between it and the drive pulley 10. Further, such a field core 20 is formed of a magnetic material. A disc-shaped mounting plate 139 is connected and fixed to the back surface of the field core 20. The mounting plate 139 is connected and fixed to a housing 130 which is a stationary system (described later). Therefore, the field core 20 is supported by a stationary system. Therefore, the field core 20 is composed of a non-rotating member.

  The rotating shaft 30 is a rotating shaft of the variable water pump 120 for an automobile engine, and is rotated coaxially with the rotating shaft center of the driving pulley 10 by receiving power from the driving pulley 10 to supply refrigerant to the engine E. Rotates integrally with the impeller 122. As shown in FIG. 2, the rotation shaft 30 is disposed with the same axis as the rotation axis of the drive pulley 10. The rotating shaft 30 is supported by a non-rotating member, that is, a stationary system regardless of whether or not rotational power is input from the engine E. Here, the electromagnetic clutch 100 is connected and fixed to a housing 130 that attaches the electromagnetic clutch 100 to the engine E. From the housing 130, an axially extending portion 131 is provided by extending the radially outer side of the rotating shaft 30 along the axial direction. In the present embodiment, the housing 130 and the axially extending portion 131 correspond to a stationary system. The rotating shaft 30 is supported via a bearing 132 on the radially inner side of the axially extending portion 131. Further, the inner cylindrical portion 13 of the drive pulley 10 is supported on the radially outer side of the axially extending portion 131 via a bearing 133.

  In the present embodiment, the impeller 122 is connected and fixed to the rotary shaft 30 via the boss portion 121. Here, the driving pulley 10 receives rotational power from the engine E via the driving belt 111. As will be described in detail later, when the electromagnetic clutch 100 puts the rotational power of the engine E into a connected state, this rotational power is input to the rotating shaft 30 to drive the impeller 122 to rotate. Thereby, the variable water pump 120 for an automobile engine can supply the refrigerant to the engine E.

  The operating member 40 is supported so as to be capable of thrust rotation with respect to the rotating shaft 30. Here, the hub portion 41 is fixed to the axial end portion of the rotating shaft 30. The hub part 41 includes a boss part 41a and a flange part 41b. The boss 41a is fitted to the axial end of the rotating shaft 30, and is connected and fixed so as to rotate integrally with the rotating shaft 30. The flange portion 41b is formed in a disk shape protruding in the radial direction from the tip portion of the boss portion 41a. The flange portion 41b is formed integrally with the boss portion 41a.

  The actuating member 40 is formed in a disc shape, and is supported coaxially with the rotary shaft 30 by a spring 95 fixed to the flange portion 41b on the end face in the axial direction. The spring 95 is fastened and fixed to the operating member 40 by a rivet 49, and fastened and fixed to the flange portion 41b by a rivet 48. The spring 95 is biased so that the operating member 40 is moved outward in the axial direction, that is, the operating member 40 is moved away from the field core 20. It is preferable to provide a plurality of such springs 95 across the flange portion 41b and the actuating member 40. As a result, the actuating member 40 is separated from the drive pulley 10 by the biasing force of the spring 95. The above-mentioned thrust rotation means that it can move along the extending direction of the rotating shaft 30 and rotates in synchronization with the rotating shaft 30. Thereby, it becomes possible for the operation member 40 and the rotating shaft 30 to rotate synchronously. Such an operating member 40 is formed of a magnetic material.

  The electromagnetic solenoid 50 is accommodated in the field core 20 while being supported by the field core 20, and generates a magnetic force for attracting and fixing the operating member 40. Here, as described above, in the present embodiment, the field core 20 is formed in an annular shape and is accommodated in the annular space 15 of the drive pulley 10. Such a field core 20 is formed with an annular groove 20A having an opening on the side of the axial end face 12B of the disk-like portion 12 of the drive pulley 10 (see FIG. 2). The electromagnetic solenoid 50 is fixed in the annular groove 20A via an insulating resin 51.

  When the electromagnetic solenoid 50 is energized, a magnetic flux is generated from the field core 20, and a magnetic path is formed by the magnetic flux. The operating member 40 is attracted to the driving pulley 10 against the biasing force of the spring 95 by this magnetic path. Thereby, the operation member 40 is rotated integrally with the drive pulley 10.

  The seal member 60 forms a sealed space 61 that is liquid-tightly sealed in at least a part of the gap between the drive pulley 10 and the field core 20. The field core 20 is disposed with a gap between the inner wall of the drive pulley 10, that is, the inner peripheral surface 11 </ b> B of the outer cylindrical portion 11 and the outer peripheral surface 13 </ b> A of the inner cylindrical portion 13. In the present embodiment, an annular core is used as the field core 20. Therefore, the above-described gap includes an annular gap along the inner peripheral surface of the field core 20, an annular gap along the outer peripheral surface, and a disc-shaped gap on the inner side of the opening of the annular space 15. In the present embodiment, the sealed space 61 is formed by fitting the annular seal member 60 into the annular gap along the inner peripheral surface of the field core 20 and the annular gap along the outer peripheral surface. Therefore, in this embodiment, the sealed space 61 is also formed in an annular shape as shown in FIG. The sealed space 61 that is liquid-tightly sealed means that the liquid does not leak from the sealed space 61 when the sealed space 61 is filled with liquid.

  Here, the drive pulley 10 rotates in synchronization with the crankshaft 110 of the engine E. On the other hand, the field core 20 is supported by a stationary system and does not rotate. The seal member 60 is disposed on the outer peripheral surface of the field core 20 as such a non-rotating portion, and the drive pulley 10 slides and rotates on the outer peripheral surface of the seal member 60. For this reason, it is necessary to use a seal member 60 that is excellent in liquid-tightness and wear resistance. For such a seal member 60, for example, a seal member used for a fluid bearing can be used. is there. Such a seal member is well known and will not be described.

  The magnetic fluid 70 is filled in the sealed space 61. The sealed space 61 is an annular space formed by fitting an annular seal member 60 into an annular gap along the inner peripheral surface of the field core 20 and an annular gap along the outer peripheral surface. Yes (see FIG. 2). For example, an isoparaffin-based magnetic fluid is preferably used as the magnetic fluid 70 filled in such an annular space. Of course, other magnetic fluids can naturally be used.

  When the electromagnetic solenoid 50 is energized, the electromagnetic solenoid 50 functions as an electromagnet. Thereby, as FIG. 3 shows, magnetic flux arises centering on the electromagnetic solenoid 50, and a magnetic path is formed. In FIG. 3, such a magnetic path is indicated by a broken line. As a result, the operating member 40 is adsorbed and supported by the drive pulley 10 against the urging force of the spring 95. Thereby, the operation member 40 is rotated together with the drive pulley 10, and the rotary shaft 30 is also rotationally driven. Therefore, the variable water pump 120 for automobile engines is driven to rotate.

  According to the electromagnetic clutch 100, since the magnetic fluid 70 is filled between the field core 20 and the drive pulley 10, the magnetic flux does not jump over the gap and is formed of a magnetic material. For this reason, since the magnetic resistance of the magnetic path can be reduced, it is not necessary to increase the number of windings of the electromagnetic solenoid 50, and it is not necessary to increase the cross-sectional area of the electromagnetic solenoid 50. Therefore, the electromagnetic clutch 100 can be configured in a compact manner.

[Other Embodiments]
In the said embodiment, it demonstrated that the sealing member 60 which forms the sealed space 61 over the circumferential direction in the gap between the drive pulley 10 and the field core 20 was provided. However, the scope of application of the present invention is not limited to this. Naturally, it is also possible to form a sealed space 61 that is liquid-tightly sealed in a part of the gap between the drive pulley 10 and the field core 20.

  In the embodiment described above, the sealed space 61 is described as being formed between the outer cylindrical portion 11 and the field core 20 and between the inner cylindrical portion 13 and the field core 20. However, the scope of application of the present invention is not limited to this. Of course, it is also possible to form the sealed space 61 only between the outer cylindrical portion 11 and the field core 20 and only between the inner cylindrical portion 13 and the field core 20.

  In the above embodiment, the field core 20 has been described as an annular core accommodated in the annular space 15. However, the scope of application of the present invention is not limited to this. Of course, the field core 20 may be formed of a non-annular core.

  INDUSTRIAL APPLICABILITY The present invention can be used for an electromagnetic clutch that intermittently inputs a power source to a variable water pump for an automobile engine.

DESCRIPTION OF SYMBOLS 10: Drive pulley 11: Outer cylindrical part 11A: Outer peripheral surface 11B: Inner peripheral surface 12: Disk-shaped part 12A: Inner peripheral surface 12B: Axial end surface 13: Inner cylindrical part 13A: Outer peripheral surface 14: Belt winding Part 15: Annular space 20: Field core 30: Rotating shaft 40: Actuating member 50: Electromagnetic solenoid 60: Seal member 61: Sealed space 70: Magnetic fluid 100: Electromagnetic clutch 110: Crankshaft 111: Drive belt 120: For automobile engine Variable water pump E: Engine

Claims (3)

An outer cylindrical portion in which a belt winding portion around which a driving belt that rotates synchronously with a crankshaft of an automobile engine is wound is formed on the outer peripheral surface, and a radially inner side at one of axial end portions of the outer cylindrical portion A drive pulley having a disk-shaped disk-shaped part extending in the direction of the axis, and an inner cylindrical part extending in the axial direction from the inner edge of the disk-shaped part and provided to face the outer cylindrical part When,
At least a part is accommodated in an annular space surrounded by the inner peripheral surface of the outer cylindrical portion, the axial end surface of the disc-shaped portion, and the outer peripheral surface of the inner cylindrical portion, and is made of a magnetic material. A field core which is a rotating part;
On the same axis as the rotational axis of the drive pulley, the rotational axis of a variable water pump for an automobile engine that rotates by receiving power from the drive pulley and supplies refrigerant to the engine;
An actuating member made of a magnetic material supported so as to be capable of thrust rotation with respect to the rotating shaft;
An electromagnetic solenoid housed in the field core in a state of being supported by the field core and generating a magnetic force for adsorbing and fixing the operating member;
A seal member that forms a sealed space liquid-tightly sealed in at least a part of a gap between the drive pulley and the field core;
A magnetic fluid filled in the sealed space;
With electromagnetic clutch.   The electromagnetic clutch according to claim 1, wherein the sealed space is formed between the outer cylindrical portion and the field core and between the inner cylindrical portion and the field core.   The electromagnetic clutch according to claim 1, wherein the field core is an annular core accommodated in the annular space.

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