JPS6212100Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electromagnetic clutch, in particular, which cuts off the power to the electromagnet when the rotating equipment is overloaded and is attached to the rotating shaft of the rotating equipment and the rotor being rotated by the source motor. This invention relates to an electromagnetic clutch equipped with a protection device for preventing destruction of a rotating machine by releasing the coupling between the disk and the rotor.

The conventional protection device of this type was Utility Model Publication No. 44-31084.
As shown in the figure, a fusible metal nut that is attached to the drive-side rotor plate and rotates together with the drive-side rotor plate is brought into close contact with the friction surface of the driven-side rotor plate to prevent the driven-side equipment from becoming overloaded. It is known to operate a protection device by melting a fusible metal nut by the frictional heat generated on the friction surface of the driven rotating plate when the driven rotating plate slows down.

However, in this conventional example, the fusible nut that detects frictional heat is fixed to the rotary plate on the drive side and rotates, so when trying to obtain an electric signal by melting this nut, the current collecting ring must be removed. It is not suitable for applying to an electromagnetic clutch to control energization/cutoff of an electromagnet. In addition, the nut wears out due to small slips that do not result in melting, and detection accuracy decreases over time.

The purpose of this invention is to detect the frictional heat generated by the sliding between the rotating plate on the driving side, that is, the rotor, and the rotating plate on the driven side, that is, the disk, without touching the rotor or disk, and to provide alarm and protection. The purpose of this invention is to enable electrical control of the device without a current collecting ring, and to prevent detection accuracy from deteriorating over time.

The feature of this invention is that a heat storage space is provided on the side of the rotor opposite to the disc coupling surface, and a part of the coil case of the electromagnet of the electromagnetic clutch is extended to this space, and the protection device is controlled by detecting frictional heat in that space. A temperature fuse is provided to detect the frictional heat caused by the sliding between the rotor, disk, and other rotating bodies without touching them.

An embodiment of the present invention shown in the drawings will be explained in detail below.

The drawings show an embodiment in which the present invention is applied to an electromagnetic clutch that transmits and disconnects the rotational force of an engine to a compressor for an air conditioner of an automobile.

A coil case 3 constituting an electromagnet is fixed to a side cover 1 of the compressor by screws 2.
A toroidal coil 9 is attached to the coil case 3. 10 is a lead wire that connects the coil 9 to a power source.

The rotor 5, which is annular and has a U-shaped cross section, is rotatably supported via a ball bearing 4 on the outer periphery of a sleeve 12 formed integrally with the coil case 3, and is supported on a V-belt stretched in a V-groove 16. It is then rotated by the engine.

An electromagnet consisting of a coil case 3 and a coil 9 is arranged in an annular space having a U-shaped cross section of the rotor 5 without contacting the rotor. At this time, a space 13 for heat storage is formed between the bottom of the U-shaped cross-sectional space of the rotor 5 and the end surface of the electromagnet on the rotor side.

A disk 8 is provided opposite the outer end surface of the rotor 5. The disk 8 is elastically supported by a leaf spring 15 to be movable in the axial direction on a hub 14 which is secured to the rotary shaft 6 of the compressor by a key 7.

A temperature fuse 11 is electrically connected in series to the coil 9 in the coil case 3, and the temperature fuse 11 detects the temperature of the heat storage space 13.
It is fixed to the coil case 3 at a position facing the space 13.

When the coil 9 is energized through the lead wire 10, a magnetic flux is generated as shown by the dashed line through the coil case 3 made of magnetic material, the rotor 5, and the disk 8, and as a result, the disk is supported so as to be movable in the axial direction. 8 is attracted and coupled to the end surface of the rotor 5 under magnetic attraction.

Thus, the rotational force of the rotor 5 is transmitted to the rotating shaft 6 via the disk 8.

When the rotary shaft 6 becomes overloaded due to seizure of the compressor or the like, the rotation of the disk 8 decreases and the coupling surface between the rotor 5 and the disk 8 slips, and this slip generates frictional heat. This frictional heat immediately raises the temperature of the heat reservoir space, which is detected by the temperature fuse 11.

Temperature fuse 1 is activated when the temperature rises above a predetermined value.
1 is fused, and the current to the coil 9 is cut off.

As a result, the magnetic attractive force between the rotor 5 and the disk 8 disappears, the coupling between the two is dissociated, and the rotation of the rotary shaft 6 of the compressor is stopped.

In this way, damage to the compressor and belt breakage due to seizure of the rotating parts can be prevented.

As explained above, according to the present invention, when detecting the overload of the driven machine using the frictional heat caused by the slippage between the rotor and the disk, the structure is configured so that the detection can be performed without contacting the rotating part, so that the overload from the detector can be detected without contacting the rotating part. Electric signals can be processed without a current collecting ring, etc., and the structure of the protection device becomes extremely simple. Furthermore, since the detection section does not wear out, the detection accuracy does not deteriorate over time.

In addition, since frictional heat is detected as a temperature rise in the air pocket, the temperature rise in the air pocket is insufficient for short-term slips that occur during startup, and as a result, the detection means does not detect such slips. , functions to prevent malfunction.

[Brief explanation of the drawing]

The figure is a sectional view of an electromagnetic clutch according to an embodiment of the present invention. 1...Side cover, 3...Coil case, 5...
...Rotor, 8...Disk, 9...Coil, 11
...Temperature fuse, 13...Heat storage space.

Claims (1)

[Claims for Utility Model Registration] 1. A rotor that rotates in response to the rotational force of a power source and a disk attached to a rotating shaft of a driven rotating body are magnetically coupled together by an attractive force of an electromagnet, and the rotor is In the device for transmitting rotational force from the rotor to the disk, a heat storage space is provided on the side opposite to the disk connection side of the rotor, a part of the coil case of the electromagnet is extended into the space, and the temperature of the space is raised to a predetermined value or higher. 1. An electromagnetic clutch with a protection device, characterized in that a temperature fuse that cuts off current to the electromagnet when the temperature rises is attached to a portion of the coil case facing the heat pool. 2 Utility Model Registration In the coil described in claim 1, an annular space having a U-shaped cross section is formed on the anti-disk coupling side of the rotor, and an annular coil constituting the electromagnet is provided in the space. An electromagnetic clutch with a protection device, characterized in that the case is housed in the rotor in a non-contact manner, and the temperature fuse is attached to the coil case at a position facing the end face of the rotor.