JP2002061673A - Electromagnetic clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce the interference noise in attracting an armature 5 to an end face of a rotor 4. SOLUTION: This electromagnetic clutch comprises a non-rotational exciting coil 2 axially movably mounted on a housing 1, a rotor 4 mounted in a state of surrounding the exciting coil 2, and rotatably held on an outer periphery of the housing 1, an armature 5 mounted close to and opposite to an end face of the rotor 4, a coupling 7 axially movably connecting the armature 5 to the rotating shaft 6, a permanent magnet 8 fixed to the housing 1 and opposite to the exciting coil 2 by the polarities different from each other from a side opposite to the armature 5, and an energizing means 9 for energizing the exciting coil 2 toward an armature 5 side. As the exciting coil 2 is displaced to a permanent magnet 8 side in being electrically energized, a distance to the armature can be kept, and the acceleration of the armature 5 in attraction process to the rotor 4 can be inhibited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic clutch, and more particularly, to an electromagnetic clutch provided in a compressor of a vehicle air conditioner.

[0002]

2. Description of the Related Art In a refrigerating cycle of a vehicle air conditioner for an automobile, an electromagnetic clutch of a compressor for compressing a refrigerant is conventionally known, for example, as shown in FIG.

That is, as shown in FIG. 6, a conventional electromagnetic clutch includes a non-rotating exciting coil 102 fixed to a housing 101 and an exciting coil 10
2 and surrounding the housing 1
01, a rotor 104 rotatably held via a bearing 103 and having a pulley 104a on its outer circumference, an armature 105 closely opposed to an end wall portion 104b of the rotor 104, and the armature 105 inserted through the housing 101. And a coupling 107 connected to the rotating shaft 106 so as to be movable in the axial direction.

A coupling 107 has a hub 7107a attached to the outer periphery of the tip end of the rotating shaft 105 via a screw member 108, and a plurality of rivets circumferentially mounted on the armature 105 concentrically arranged on the outer periphery of the hub 7107a. An outer ring 107b connected via
An elastic body 107c made of an annular rubber-like elastic material is vulcanized and bonded between the outer peripheral surfaces of the outer ring 107b and the rim of the hub 7107a.

That is, the coupling 107 prevents the armature 105 from moving in the axial direction and being attracted to the end wall 104b of the rotating rotor 104 by the magnetic force when the exciting coil 102 is energized. In addition to allowing the deformation, the noise at the time of suction between the armature 105 and the rotor 104 is reduced, and the armature 10
5 transmits the torque to the rotating shaft 106. Also, when the excitation coil 102 is not energized, the elastic member 107
armature 105 by rotor c
Is separated from the end face by a predetermined distance.

[0006]

FIG. 7 shows the relationship between the amount of movement of the armature 105, the magnetic force acting on the armature 105, and the shear spring load of the elastic body 107c of the coupling 107. That is, by energizing the excitation coil 102, the armature 105
Magnetic force acting on the rotor 104
In the process of moving to the end wall portion 104b side, while increasing non-linearly, the armature 105 to the rotor 104 side
The shear spring load of the elastic body 107c acting as a drag against the movement of the armature 105 also increases with the movement of the armature 105, but the increase is almost linear. Therefore, immediately before the armature 105 is attracted to the end wall portion 104b, the attracting force F, which is the difference between the magnetic force and the shear spring load, rapidly increases, and the armature 105 is moved to the end wall portion 10b.
There is a problem that it is strongly adsorbed to 4b and generates a large interference sound.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its main technical problem to effectively reduce interference noise when an armature is attracted to an end face of a rotor. It is in.

[0008]

Means for Solving the Problems As means for effectively solving the above technical problems, an electromagnetic clutch according to the present invention comprises a non-rotating exciting coil disposed in a housing so as to be movable in the axial direction, and A rotor rotatably held by the housing and magnetized by the excitation coil; an armature closely opposed to an end wall of the rotor and magnetized by the excitation coil; and a rotation having the armature inserted through the inner periphery of the housing. A coupling that is connected to the shaft so as to be movable in the axial direction, a magnet that is fixed to the housing and faces the excitation coil with different poles from the side opposite to the armature from the armature, and the excitation coil is moved toward the end wall. Biasing means for biasing toward the front.

Further, as another means for effectively solving the above-mentioned technical problem, an electromagnetic clutch according to the present invention comprises a non-rotating exciting coil disposed in a housing so as to be movable in an axial direction, and an electromagnetic coil provided in the housing. A rotor rotatably held and magnetized by the exciting coil; an armature closely opposed to an end wall of the rotor and magnetized by the exciting coil; and a rotating shaft having the armature inserted through the inner periphery of the housing. A coupling that is connected to the coupling so as to be movable in the axial direction, a magnet that is fixed to the coupling and faces the excitation coil with the same polarity, and a bias that biases the excitation coil toward the end wall. Means.

[0010]

FIG. 1 is a sectional view showing a first embodiment of an electromagnetic clutch according to the present invention. In FIG. 1, reference numeral 1 denotes an end of a housing 1 of a compressor in a vehicle air conditioner of an automobile, 2 denotes a non-rotating exciting coil disposed in the housing 1, and 4 denotes a ball bearing 3 mounted on the housing 1. The rotor 5 is rotatably held via an armature, 5 is an armature disposed close to and opposed to the outside of the rotor 4 in the axial direction, 6 is a rotating shaft inserted through the inner periphery of the housing 1, 7 is a rotating shaft of the armature 5. 6 is a coupling that is connected to the motor 6 so as to be movable in the axial direction. The rotor 4 and the armature 5 are both
Made of a magnetic metal that is magnetized by the magnetic field generated in the magnetic field.

The exciting coil 2 is axially movable with respect to the housing 1. A permanent magnet 8 is fixed to the housing 1 at a position opposite to the armature 5 with respect to the exciting coil 2. A rubber bush 9 is disposed between the permanent magnet 8 and the exciting coil 2 as urging means for urging the exciting coil 2 toward the armature 5.

The housing 1 has an inner peripheral side bearing support cylindrical portion 1a and an outer peripheral side holding ring portion 1b formed concentrically. The ball bearing 3 has an inner race 3a formed by the bearing support cylindrical portion. 1a is fitted on the outer peripheral surface. Further, the rotor 4 has an inner peripheral cylindrical portion 4 a whose inner peripheral surface is fitted to the outer race 3 b of the ball bearing 3.
An end wall portion 4b extending in a disc shape between the holding ring portion 1b of the housing 1 and the armature 5, and a pulley portion 4c extending from the outer diameter end of the end wall portion 4b along the outer peripheral side of the holding ring portion 1b. , That is, a cross-sectional shape surrounding the holding ring portion 1b in a substantially U-shape.

A plurality of hollow portions 1c are formed in the holding ring portion 1b of the housing 1 at equal intervals in the circumferential direction, and the exciting coil 2, the permanent magnet 8 and the rubber bush 9 are provided in each of the hollow portions 1c. Are arranged in the axial direction. More specifically, the exciting coil 2 is disposed at a position near the armature 5 in the hollow portion 1c, in other words, at a position near the end wall portion 4b of the rotor 4 so as to be movable in the axial direction. Is fixed to the end opposite to the armature 5 in the hollow portion 1c.

The rubber bush 9 is formed of a rubber-like elastic material into a tubular shape.
b, the excitation coil 2 and the permanent magnet 8 in each hollow portion 1c.
And between the inner surface of the hollow portion 1c and
Has appropriate clearance. The rubber bush 9 may be bonded to one or both of the exciting coil 2 and the permanent magnet 8.

The axis of the exciting coil 2 and the magnetic pole of the permanent magnet 8 are arranged in the axial direction. The exciting coil 2 generates a magnetic field in the same direction as the magnetic field of the permanent magnet 8 when energized. That is, the exciting coil 2 is applied to the exciting coil 2 so that the exciting coil 2 and the permanent magnet 8 face each other with different polarities. The direction of the exciting current is set. Therefore, the exciting coil 2
When energized, the rubber bush 9 is moved toward the permanent magnet 8 by a predetermined distance while compressively deforming the rubber bush 9 by the attractive force between the different poles acting between the rubber bush 9 and the permanent magnet 8.

The coupling 7 has a hub 71 attached to the tip of the rotating shaft 6 via a screw member 74, and a plurality of rivets 75 in the circumferential direction on the armature 5 of the electromagnetic clutch.
And an elastic body 73 that elastically connects the hub 71 and the outer ring 72 to each other. The elastic body 73 is formed of a rubber-like elastic material in an annular shape, and has an outer peripheral surface of a rim portion 71a of the hub 71 and an inner peripheral surface of the outer ring 72 concentrically arranged on the outer peripheral side thereof. And vulcanized.

FIG. 2 shows the operation of the electromagnetic clutch according to the first embodiment configured as described above.
The rotor 4 is rotated by a driving force from a crank pulley or the like of an engine via a belt (not shown) wound around a pulley 4c.

Here, when the exciting coil 2 is energized, the magnetic field generated thereby magnetizes the rotor 4 and the armature 5. For this reason, as shown in FIG. 2A, the armature 5 is connected to the elastic body 73 of the coupling 7.
End wall portion 4b of rotor 4
It is displaced in the axial direction toward the side, and is attracted to its end face to be in a clutch meet state. At this point, the rotational torque of the rotor 4 is transmitted from the armature 5 to the rotary shaft 6 via the outer ring 72, the elastic body 73, and the hub 71 of the coupling 7, so that the compressor (and, consequently, the air conditioner) operates. Becomes

Regarding the adsorption process of the armature 5,
More specifically, first, in the initial state at the time when the exciting coil 2 is energized, the exciting coil 2 is in a position close to the end wall portion 4b of the rotor 4, so that the elastic member 73 is attached to the armature 5. The required magnetic force required to start the movement toward the rotor 4 against the axial shear spring load is provided.

On the other hand, the magnetic field generated by energizing the exciting coil 2 is in the same direction as the magnetic field of the permanent magnet 8, so that the exciting coil 2 and the permanent magnet 8 face each other with different polarities and attract each other. Therefore, as shown in FIG. 2A, the exciting coil 2 that is axially movable with respect to the housing 1 moves toward the permanent magnet 8 while compressing the rubber bush 9 while being energized. I do. Therefore, even if the armature 5 is displaced in the axial direction toward the rotor 4 by the magnetic force, a decrease in the distance between the armature 5 and the exciting coil 2 is suppressed. In addition, since the rubber bush 9 has an appropriate clearance with respect to the inner surface of the hollow portion 1c,
It is flexibly compressed and deformed between the exciting coil 2 and the permanent magnet 8 while expanding toward the outer peripheral side.

FIG. 3 is an explanatory diagram showing the relationship between the amount of movement of the armature 5 toward the rotor 4 and the magnetic force acting on the armature 5 and the shear spring load of the elastic body 73 of the coupling 7. That is, as described above, even if the armature 5 is axially displaced toward the rotor 4 by the magnetic force, the exciting coil 2 also moves in the same direction, so that the distance between the armature 5 and the exciting coil 2 does not become so short. Therefore, as shown in FIG. 3, the magnetic force acting on the armature 5 is suppressed to a level slightly larger than the shear spring load of the elastic body 73 of the coupling 7 that increases with the movement of the armature 5. As a result, the end wall portion 4b of the rotor 4
The acceleration when the armature 5 is sucked is suppressed, and the interference sound at the time of sucking is effectively reduced.

Further, at the same time that the armature 5 is attracted to the end wall portion 4b of the rotor 4, the impact caused by the sudden input of the rotational torque of the rotor 4 to the armature 5 is caused by the torsion of the elastic body 73 of the coupling 7. The directional shearing action effectively mitigates.

Next, when the supply of the exciting current to the exciting coil 2 is cut off from the operating state of the compressor in which the armature 5 is attracted to the rotor 4, the magnetic attraction force of the armature 5 is released. Due to the elastic restoring force of the elastic body 73, the armature 5 is separated from the end wall 4b of the rotor 4, and is returned as shown in FIG. Therefore, transmission of the rotation torque from the rotor 4 via the armature 5 and the coupling 7 is interrupted, and the rotation of the rotation shaft 6 stops.

On the other hand, since the attractive force between the exciting coil 2 and the permanent magnet 8 is eliminated, the exciting coil 2 is pushed back to the end wall 4b side of the rotor 4 by the restoring force of the rubber bush 9 in the compressed state. It returns to the position shown in FIG.

FIG. 4 is a sectional view showing a second embodiment of the electromagnetic clutch according to the present invention. This electromagnetic clutch differs from the first embodiment described above in that the permanent magnet 8 is connected to the hub 71 of the coupling 7.
When the excitation coil 2 is energized, a magnetic field in the opposite direction to the magnetic field of the permanent magnet 8 is generated,
That is, the direction of the exciting current to the exciting coil 2 is set so that the exciting coil 2 and the permanent magnet 8 face each other with the same polarity.

The other parts are basically the same as those of the first embodiment shown in FIG. That is, the non-rotating exciting coil 2 is disposed so as to be axially movable in the hollow portion 1c formed in the holding ring portion 1b of the housing 1, and is arranged so as to surround the holding ring portion 1b in a substantially U-shaped cross section. A rotor 4 rotatably held by a bearing support cylinder portion 1a of the housing 1 via a ball bearing 3; an armature 5 disposed close to and axially outside the end wall portion 4b of the rotor 4 in the axial direction; Coupling 7 for connecting armature 5 to rotating shaft 6 so as to be movable in the axial direction.
And an exciting coil 2 disposed in the hollow portion 1c.
And a rubber bush 9 for urging the armature 5 toward the armature 5 side.

FIG. 5 shows the operation of the electromagnetic clutch according to the second embodiment configured as described above.
The rotor 4 is rotated by a driving force from a crank pulley or the like of an engine via a belt (not shown) wound around a pulley 4c.

When the exciting coil 2 is energized, the magnetic field generated thereby magnetizes the rotor 4 and the armature 5. For this reason, as shown in FIG.
The armature 5 is axially displaced toward the end wall portion 4b of the rotor 4 while being subjected to the axial shearing deformation of the elastic body 73 of the coupling 7, and is attracted to the end face to be in a clutch meet state. At this point, the rotating torque of the rotor 4 is transmitted from the armature 5 to the rotating shaft 6 via the outer ring 72, the elastic body 73, and the hub 71 of the coupling 7, and the compressor (and the air conditioner) enters an operating state.

In the initial state when the exciting coil 2 is energized, the exciting coil 2 is located close to the end wall 4 b of the rotor 4, so that the armature 5 resists the elasticity of the elastic body 73. Thus, a required magnetic force necessary to start the movement to the rotor 4 side is given.

On the other hand, since the magnetic field generated in the energized exciting coil 2 is in the opposite direction to the magnetic field of the permanent magnet 8 provided in the hub 71, the exciting coil 2 and the permanent magnet 8 must be opposed with the same polarity. And repel each other. Therefore, FIG.
As shown in (A), the exciting coil 2 that is movable in the axial direction moves in a direction away from the permanent magnet 8 while compressing the rubber bush 9 at the same time as being energized.

That is, even if the armature 5 is axially displaced toward the rotor 4 by the magnetic force, the exciting coil 2 also moves in the same direction, so that the distance between the armature 5 and the exciting coil 2 does not become so short. Therefore, as shown in FIG. 3, the magnetic force acting on the armature 5 is suppressed to a level slightly larger than the shear spring load of the elastic body 73 of the coupling 7 which increases with the movement of the armature 5. As a result, the armature 5 is attached to the end wall 4b of the rotor 4.
Acceleration at the time of suction is suppressed, and interference noise at the time of suction is effectively reduced.

Next, when the supply of the exciting current to the exciting coil 2 is interrupted from the operating state of the compressor in which the armature 5 is attracted to the end wall portion 4b of the rotor 4, the magnetic attraction force to the armature 5 is released. The coupling 7
Due to the elastic restoring force of the elastic body 73, the armature 5 separates from the end wall portion 4b and performs a returning operation as shown in FIG. Therefore, transmission of the rotation torque from the rotor 4 via the armature 5 and the coupling 7 is interrupted, and the rotation of the rotation shaft 6 is stopped.

On the other hand, since the repulsive force between the exciting coil 2 and the permanent magnet 8 is eliminated, the exciting coil 2 is pushed back toward the end wall portion 4b of the rotor 4 by the restoring force of the rubber bush 9 in the compressed state. It returns to the position shown in FIG.

The present invention is not limited by the illustrated embodiment. For example, as urging means for urging the exciting coil 2 toward the armature 5 side,
An elastic body other than the rubber bush 9 can be used.

[0035]

According to the electromagnetic clutch according to the first aspect of the present invention, when the exciting coil is energized, the exciting coil attracts the permanent magnet, and the moving direction of the armature is controlled against the urging force of the urging means. Since the armature moves in the same direction, even if the armature is axially displaced to the rotor side, a decrease in the distance between the armature and the exciting coil is suppressed, and as a result,
Acceleration in the process in which the armature is attracted to the end wall of the rotor is suppressed, and interference noise during the attraction can be effectively reduced.

According to the electromagnetic clutch of the second aspect of the present invention, when the exciting coil is energized, the exciting coil repels the permanent magnet fixed to the coupling to reduce the urging force of the urging means. Since the armature moves in the same direction as the moving direction of the armature, even if the armature is axially displaced toward the rotor, a decrease in the distance between the armature and the exciting coil is suppressed, and as a result, the armature is attached to the end wall of the rotor. Acceleration in the process of adsorbing is suppressed, and interference noise at the time of adsorbing can be effectively reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of an electromagnetic clutch according to the present invention, cut along a plane passing through an axis.

FIG. 2 is a half sectional view showing an operation according to the first embodiment,
(A) shows when the exciting coil is energized, and (B) shows when the exciting coil is not energized.

FIG. 3 is an explanatory diagram showing the relationship between the amount of movement of the armature according to the first embodiment, the magnetic force acting on the armature, and the shear spring load of the elastic body of the coupling.

FIG. 4 is a cross-sectional view showing a second embodiment of the electromagnetic clutch according to the present invention by cutting along a plane passing through an axis.

FIG. 5 is a half sectional view showing an operation according to the second embodiment,
(A) shows when the exciting coil is energized, and (B) shows when the exciting coil is not energized.

FIG. 6 is a cross-sectional view showing an electromagnetic clutch according to a conventional technique, cut along a plane passing through an axis.

FIG. 7 is an explanatory diagram showing the relationship between the amount of movement of an armature according to a conventional technique, the magnetic force acting on the armature, and the shear spring load of an elastic body of the coupling.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 1c Hollow part 2 Excitation coil 3 Ball bearing 4 Rotor 4b End wall part 4c Pulley part 5 Armature 6 Rotating shaft 7 Coupling 71 Hub 72 Outer ring 73 Elastic body 8 Permanent magnet 9 Rubber bush (biasing means)

Claims (2)

[Claims] 1. A non-rotating exciting coil (2) arranged axially movable in a housing (1), and a rotor rotatably held by the housing (1) and magnetized by the exciting coil (2). (4) an armature (5) which is closely opposed to an end wall (4b) of the rotor (4) and is magnetized by the exciting coil (2); and the armature (5) is inserted into the housing (1). A coupling (7) that is connected to the rotating shaft (6) inserted in the periphery so as to be movable in the axial direction; and the excitation coil (2) fixed to the housing (1).
And a biasing means (9) for biasing the excitation coil (2) toward the end wall (4b) side from a magnet (8) opposed to the armature (5) from a side opposite to the armature (5). And an electromagnetic clutch comprising: 2. A non-rotating exciting coil (2) arranged in the housing (1) so as to be movable in the axial direction, and a rotor rotatably held by the housing (1) and magnetized by the exciting coil (2). (4) an armature (5) which is closely opposed to an end wall (4b) of the rotor (4) and is magnetized by the exciting coil (2); and the armature (5) is inserted into the housing (1). A coupling (7) that is connected to the rotating shaft (6) inserted in the periphery so as to be movable in the axial direction, and is fixed to the coupling (7) and faces the exciting coil (2) with the same polarity. An electromagnetic clutch, comprising: a magnet (8); and an urging means (9) for urging the exciting coil (2) toward the end wall (4b).