Electromagnetic clutch

Patent metadata

Field	Value
Publication number	US-9945430-B2
Application number	US-201515317511-A
Country	US
Kind code	B2
Filing date	Nov 26, 2015
Priority date	Dec 5, 2014
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

A thermal fuse is covered with a case that has a slit. A capacity of the case is larger than a volume of the thermal fuse, and the case has a space that is formed between an inner wall surface of the case and the thermal fuse. The slit is formed in the case introduce radiant heat, which is generated at a friction surface of a rotor, into an inside of the case. Thereby, the radiant heat, which is inputted into the inside of the case through the slit, can be reflected by the inner wall surface of the case and thereafter can be absorbed by the thermal fuse.

First claim

The invention claimed is:

1. An electromagnetic clutch comprising:
an electromagnetic coil that generates an electromagnetic attractive force when the electromagnetic coil is energized;
a rotor that is rotated about a rotation center axis when the rotor receives a rotational drive force from a drive source, wherein the rotors includes a first surface and a second surface, which are spaced away from each other in an axial direction of the rotation center axis, and the first surface and the second surface extend in a direction perpendicular to the axial direction;
an armature that is connectable with a rotatable shaft of a driven-side device, wherein the armature is attracted to and attached to the first surface of the rotor by the electromagnetic attractive force when the electromagnetic coil is energized, and the armature is detached from the first surface of the rotor when the electromagnetic coil is not energized;
a stator that is opposed to the second surface of the rotor in the axial direction and forms a space between the stator and the second surface, wherein the stator has an opening on a side wherein the second surface is located, and the stator receives the electromagnetic coil in an inside space of the stator, which is communicated with the opening;
a resin member that closes the opening of the stator and seals the electromagnetic coil in the inside space of the stator;
a case that is held by a portion of the resin member, which is located in the opening of the stator; and
a thermal fuse that is received in an inside of the case and cuts supply of an electric current to the electromagnetic coil when a temperature of the thermal fuse equal to or higher than a predetermined temperature, wherein:
the case has a gap, through which radiant heat generated at the first surface is introduced into the inside of the case;
a capacity of the case is larger than a volume of the thermal fuse; and
the case has a space that is formed between an inner wall surface of the case and the thermal fuse.

2. The electromagnetic clutch according to claim 1 , wherein:
the thermal fuse includes:
a main body portion; and
a lead wire, which electrically connects between the main body portion and the electromagnetic coil;

a portion of the lead wires, which is placed at an outside of the case, is held by the resin member; and
the thermal fuse contacts the inner wall surface of the case with a predetermined contact pressure, which is generated by a resilient force of the lead wire.

3. The electromagnetic clutch according to claim 1 , wherein a portion of the case, which forms the inner wall surface of the case, is made of a metal material that has a metallic luster color.

4. The electromagnetic clutch according to claim 1 , wherein a portion of the case, which forms the inner wall surface of the case, is made of a non-metallic material having a white color.

5. The electromagnetic clutch according to claim 1 , wherein the inner wall surface of the case is in a form of a recessed curved surface.

6. The electromagnetic clutch according to claim 1 , wherein:
the case is in a cylindrical tubular form and is opened at both of one end and another end of the case along a direction of a central axis of the case; and
the gap is a slit that extends along the direction of the central axis.

7. An electromagnetic clutch comprising:
an electromagnetic coil that generates an electromagnetic attractive force when the electromagnetic coil is energized;
a rotor that is rotated about a rotation center axis when the rotor receives a rotational drive force from a drive source, wherein the rotor includes a first surface and a second surface, which are spaced away from each other in an axial direction of the rotation center axis, and the first surface and the second surface extend in a direction perpendicular to the axial direction;
an armature that is connectable with a rotatable shaft of a driven-side device, wherein the armature is attracted to and attached to the first surface of the rotor by the electromagnetic attractive force when the electromagnetic coil is energized, and the armature is detached from the first surface of the rotor when the electromagnetic coil is not energized;
a stator that is opposed to the second surface of the rotor in the axial direction and forms a space between the stator and the second surface, wherein the stator has an opening on a side wherein the second surface is located, and the stator receives the electromagnetic coil in an inside space of the stator, which is communicated with the opening;
a resin member that closes the opening of the stators and seals the electromagnetic coil in the inside space of the stator;
a case that is held by a portion of the resin member, which is located in the opening of the stator; and
a thermal fuse that is received in an inside of the case and cuts supply of an electric current to the electromagnetic coil when a temperature of the thermal fuse is equal to or higher than a predetermined temperature, wherein:
the case has a gap, through which radiant heat generated by slipping between the armature and the rotor at a time of occurrence of locking of the driven-side device during energization of the electromagnetic coil is introduced into the inside of the case;
a capacity of the case is larger than a volume of the thermal fuse; and
the case has a space between an inner wall surface of the case and the thermal fuse.

Assignees

• Denso Corp

Inventors

• Fukumura Yoshinori

Classifications

• F16D27/06 Primary

  with friction surfaces arranged within the flux · CPC title

• F16D27/14

  Details · CPC title

• F16D28/00

  Electrically-actuated clutches (arrangements for synchronisation F16D23/02; clutches actuated directly by means of an electromagnet F16D27/00; automatic clutches F16D43/00 - F16D45/00; external control F16D48/00) · CPC title

• F16D2300/18

  Sensors; Details or arrangements thereof · CPC title

• F16H7/0827

  for disconnecting the drive · CPC title