JPH10281183A - Electromagnetic clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce working noise during engagement of a clutch without using another component. SOLUTION: An electromagnetic clutch 1 comprises an exciting coil to generate a magnetic force by effecting electrical energization thereto; a stator to support the exciting coil; a rotor to be rotated through transmission of the rotation force of an engine thereto; an armature 5 attracted to a rotor during electrical connection to the excitation coil; and hub indenters 12, 13, and 14 to hold the armature 5. The armature 5 is formed such that columnar coupling pins 11 being a coupling means being a coupling means to the hub indenters 12, 13, and 14 are fixed three spots arranged at equal intervals in a peripheral direction. Further, A rib 5a protruded from the surface on the opposite rotor side of the armature 5 is formed on an approximate intermediate part between the coupling pins 11 in a peripheral direction of the armature 5. The rib 5a changes rigidity of the armature 5 by increasing the thickness of the armature 5 and is formed through, for example, cold forge processing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic clutch for intermittently transmitting rotational power.

[0002]

2. Description of the Related Art Conventionally, there is an electromagnetic clutch used for, for example, an air conditioner for a vehicle. The electromagnetic clutch includes a rotor that rotates by receiving the rotational force of the engine, and an armature that is opposed to the rotor and supported by an elastic body (e.g., rubber or a leaf spring), and a built-in excitation coil is energized. Then, the armature is attracted to the rotor side against the reaction force of the elastic body and rotates integrally with the rotor, so that the rotational force of the engine can be transmitted to the rotating shaft of the refrigerant compressor. In this electromagnetic clutch, since the armature collides with the rotor and vibrates when the clutch is connected, a large operating noise is generated. Is being reduced.

[0003]

However, in the electromagnetic clutch using the above-mentioned cushioning material, since the cushioning material is a separate component from the components of the clutch, the structure becomes complicated by adding the cushioning material, and the cost is reduced. There was a problem of inviting up. The present invention has been made based on the above circumstances, and an object of the present invention is to provide an electromagnetic clutch that can reduce operating noise when a clutch is connected without using another component.

[0004]

[Means for Solving the Problems]

The armature has connecting portions connected to the elastic body at a plurality of locations which are maintained at substantially equal intervals in the circumferential direction, and changes the rigidity of the armature at a substantially central portion between the connecting portions. A change means is provided. In this case, a change in the rigidity of the armature changes the vibration mode of the armature generated when the armature is attracted to the rotor. As a result, the vibration frequency of the operation sound generated when the clutch is engaged is changed, and it is possible to reduce the operation sound that is unpleasant for the occupant.

(Means of Claim 2) The changing means provided on the armature is a rib projecting on the surface of the armature. In this case, for example, the ribs can be formed by partially increasing the wall thickness of the armature (for example, formed by cold forging), and the rigidity of the armature can be changed with a simple configuration. Therefore, there is no need to use separate parts as in the prior art, and the structure does not become complicated.

(Means of Claim 3) The changing means provided on the armature is a concave portion which is depressed on the surface of the armature. In this case, the rigidity of the armature can be changed by a simple configuration in which a recess such as a notch is provided on the surface of the armature. Therefore, there is no need to use separate parts as in the prior art, and the structure does not become complicated.

[0007]

Next, an electromagnetic clutch according to the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is a plan view of an electromagnetic clutch 1 viewed from the axial direction (left side in FIG. 3). The electromagnetic clutch 1 of the present embodiment is mounted on, for example, a refrigerant compressor (not shown) of an automobile refrigeration cycle, and transmits or shuts off the rotational power of the engine to the refrigerant compressor. As shown in FIG. 3, the electromagnetic clutch 1 includes an exciting coil 2 that generates a magnetic force when energized, a stator 3 that supports the exciting coil 2, and a rotor 4 that rotates by transmitting the torque of the engine.
And an armature 5 that is attracted to the rotor 4 when the excitation coil 2 is energized, and a hub assembly (described later) that holds the armature 5.

The excitation coil 2 is a well-known coil formed by winding a coil wire coated with an insulating coating on a resin spool 6. After being housed inside the stator 3, it is molded and fixed with an epoxy resin 7 or the like. Is done. The stator 3 is made of a magnetic material such as iron or low-carbon steel, and forms a magnetic circuit of the exciting coil 2 together with the rotor 4 and the armature 5, which are also magnetic materials. The stator 3 has an annular arm support 8 joined to the right end face in FIG. 3, and the arm support 8 is fixed to a housing of the refrigerant compressor by a circlip (not shown) and is positioned in the axial direction.

The rotor 4 is formed in an annular shape having a U-shaped cross section (inverted U-shaped in FIG. 3) for accommodating the stator 3, and is rotatable to a housing of the refrigerant compressor via a bearing 9 disposed on the inner periphery thereof. It is supported by. The rotor 4 has a pulley 10 fixed to an outer peripheral surface in a radial direction.
The rotation power of the engine is transmitted via a belt (not shown) that is wound around the vehicle and rotates. Also, the rotor 4
An axial surface facing the armature 5 is formed as a friction surface.

The armature 5 is formed in an annular shape and is arranged to face the friction surface of the rotor 4. The surface of the armature 5 on the rotor 4 side is formed as a friction surface similarly to the friction surface of the rotor 4. On the armature 5, cylindrical connecting pins 11 as connecting means for connecting to a hub assembly are fixed at three places which are kept at equal intervals in the circumferential direction. Also,
As shown in FIG. 1, a rib 5a projecting from the surface of the armature 5 on the side opposite to the rotor 4 (the left side surface in FIG. 3) is provided at a substantially intermediate portion between the connecting pins 11 in the circumferential direction of the armature 5. . As shown in FIG. 2 (A view in FIG. 1), the ribs 5a increase the thickness of the armature 5 to increase the thickness of the armature 5.
(In this case, the rigidity is increased), and can be formed by, for example, cold forging.

The hub assembly includes an inner hub 12 for transmitting a rotational force to a rotating shaft of the refrigerant compressor, a hub plate 13 fixed to the inner hub 12, and a hub plate 1
3 comprises a rubber hub 14 and the like. The inner hub 12 has a cylindrical boss portion 12a as shown in FIG. 3, and the boss portion 12a is fitted to the rotating shaft of the refrigerant compressor and fixed to the rotating shaft by a bolt (not shown). As shown in FIG. 1, the hub plate 13 has a substantially triangular planar shape when viewed from the axial direction, and is fixed to the inner hub 12 by rivets 15 or the like. The hub plate 13 is formed with a cylindrical wall portion 13a that is depressed in a circular shape at each of three ends (each of the tops of a triangle). The rubber hub 14 is formed into a ring shape and
3 is accommodated in each cylindrical wall portion 13a, and the outer peripheral surface thereof is bonded and fixed to the inner peripheral surface of the cylindrical wall portion 13a. Further, a connection pin 11 fixed to the armature 5 is inserted into the inner periphery of the rubber hub 14, and is adhesively fixed to the outer peripheral surface of the connection pin 11.

Next, the operation of this embodiment and the effects of the invention will be described. When the exciting coil 2 is energized to generate a magnetic force,
The armature 5 is opposed to the rotor 4 against the elastic force of the rubber hub 14.
The rotation of the rotor 4 is transmitted to the armature 5 by being attracted to the side and the friction surface of the armature 5 being attracted to the friction surface of the rotor 4 and frictionally engaging with each other. The rotor 4
The power of the engine is transmitted via a belt stretched over the pulley 10, and the engine is constantly rotating when the engine is operating. The rotation of the armature 5 is transmitted to the rubber hub 14 → the hub plate 13 → the inner hub 12 through the connecting pin 11, whereby the rotating shaft of the refrigerant compressor to which the inner hub 12 is fixed rotates. When the energizing of the exciting coil 2 is stopped and the attraction force is extinguished, the archer 5 which has been attracted to the rotor 4 until then is removed from the rubber hub 14.
Is separated from the rotor 4 by the elastic force. As a result, the transmission of the rotational force between the rotor 4 and the armature 5 is interrupted, so that the rotational power of the engine is not transmitted to the rotating shaft of the refrigerant compressor.

In this operation, the conventional electromagnetic clutch 1
In this case, an unpleasant operation sound is generated by the vibration of the armature 5 generated when the clutch is engaged. As shown in the model diagram of FIG. 4, the vibration of the armature 5 has the largest amplitude at the connection portion of the armature 5 (the portion fixed to the hub plate 13 by the connection pin 11), and the vibration between the connection portions is substantially the same. The center is the node of the amplitude. On the other hand, in the present embodiment, the ribs 5a are provided substantially at the intermediate portions of the connecting pins 11 which are nodes of the amplitude of the armature 5, thereby improving the rigidity of the armature 5 and suppressing the deformation of the armature 5. Therefore, the problematic vibration mode is eliminated. This means
When the resonance level of the armature 5 is measured, the resonance level of the conventional armature without the rib 5a increases at a certain frequency H, as shown in FIG. 5, whereas the armature 5 of the present embodiment with the rib 5a has the rib 5a. 6, it can be seen from the fact that the resonance level at the same frequency H is kept low. Thus, according to the present embodiment, the armature 5
By changing the resonance characteristics of the armature 5 by changing the rigidity of the armature 5, harsh operating noise can be reduced. In addition, the operating noise can be reduced with a simple configuration in which the armature 5 is provided with the ribs 5a without using a cushioning material or the like, which is a separate component from the clutch components, thereby suppressing an increase in cost.

(Second Embodiment) FIG. 7 is a plan view of the electromagnetic clutch 1 viewed from the axial direction. In this embodiment, as a means for changing the rigidity of the armature 5, a notch 5b is provided on the surface of the armature 5 on the side opposite to the rotor 4, as shown in FIG. 8 (B view in FIG. 7). Notch 5b
Are provided substantially at the intermediate portions between the connecting pins 11 in the circumferential direction of the armature 5 similarly to the rib 5a of the first embodiment (see FIG. 7). In this case, the armature 5 is divided into three equal parts in the circumferential direction by the notch 5b, and the movement of each part is independent. Therefore, the problematic vibration mode is eliminated, and the operating noise can be reduced.

In the above embodiment, the rubber hub 14 is used as a means for applying a reaction force for separating the armature 5 from the rotor 3 when the power supply to the exciting coil 2 is stopped. However, for example, a metal plate spring may be used.

[Brief description of the drawings]

FIG. 1 is a plan view of an electromagnetic clutch.

FIG. 2 is a partial cross-sectional view of a rib provided on an armature.

FIG. 3 is a side half sectional view of an electromagnetic clutch.

FIG. 4 is a model diagram showing a vibration mode of an armature.

FIG. 5 is a graph illustrating the resonance characteristics of a conventional armature.

FIG. 6 is a graph showing a measured resonance characteristic of the armature according to the present embodiment.

FIG. 7 is a plan view of an electromagnetic clutch (second embodiment).

FIG. 8 is a side view showing a cutout portion of the armature (second embodiment).

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electromagnetic clutch 2 excitation coil 4 rotor 5 armature 5 a rib (change means) 5 b notch (recess / change means) 11 connection pin (connection part) 12 inner hub (output member) 13 hub plate (output member) 14 rubber hub (elastic body) )

Claims (3)

[Claims] A rotor that rotates by receiving a rotation force of a drive source; an excitation coil that is energized to generate a magnetic force; an armature that is attracted to the rotor when the excitation coil is energized and rotates integrally with the rotor An elastic body coupled to the armature to apply a reaction force to the armature in a direction away from the rotor, and to disconnect the armature from the rotor when power supply to the excitation coil is stopped; and An output member to which the rotational force of the armature is transmitted to output the armature, wherein the armature has a connecting portion that is connected to the elastic body at a plurality of locations that keep substantially equal intervals in a circumferential direction. An electromagnetic clutch, wherein a change means for changing the rigidity of the armature is provided at a substantially central portion between the connecting portions. 2. The electromagnetic clutch according to claim 1, wherein said changing means is a rib projecting on a surface of said armature. 3. The electromagnetic clutch according to claim 1, wherein said changing means is a concave portion recessed on a surface of said armature.