Abstract: When a control unit starts to supply power to an electromagnetic coil in a first direction, a magnetic force generated by a non-attracting magnetic circuit becomes larger than a magnetic attraction force generated by an attracting magnetic circuit. As a result, a movable member is guided by a guide portion of a yoke and moves to a second position from a first position. When the control unit starts to supply power to an electromagnetic coil in a second direction, the magnetic attraction force generated by the attracting magnetic circuit becomes larger than the magnetic force generated by the non-attracting magnetic circuit. As a result, the movable member is guided by the guide portion and moves to the first position from the second position. Accordingly, the movable member can reliably perform a moving operation when turning ON/OFF.

Abstract: A clutch includes: a rotor that has a steel material as a base material and is rotated upon receiving a rotational drive force from a drive source; and an armature that has a steel material as a base material and receives the rotational drive force from the rotor when the armature is attracted to the rotor by a magnetic force. The armature has a contact surface side region that includes a contact surface, which contacts a counterpart when the armature is attracted to the rotor. The contact surface side region has a plurality of pores opened at the contact surface and forms a nitride compound of an element of the base material through nitridization of a part of the base material while the contact surface side region is harder than an unreacted portion of the base material that is not reacted at the nitridization.

Abstract: A ring insertion groove is formed between adjacent two of circular plates, which are made of a magnetic material and are arranged concentric with each other, and a ring, which is made of a non-magnetic material and has a larger deformation resistance in comparison to the magnetic material of the plates, is press fitted into the ring insertion groove. Thereafter, a peripheral part around an opening of the ring insertion groove is plastically flowed, so that a compression stress is left in the ring.

Abstract: When a clutch relay connects between a control device and a vehicle electric power source in response to outputting of a clutch OFF signal from an electronic control device to the clutch relay, a timer circuit starts a control operation for energizing coil portions. When a predetermined time period elapses, the timer circuit terminates energization of the coil portions. When the clutch relay connects between the control device and the vehicle electric power source in response to outputting of a clutch ON signal from the electronic control device to the relay, the timer circuit starts a control operation for energizing the coil portions. When a predetermined time period elapses, the timer circuit terminates energization of the coil portions.

Abstract: A recess, which has a bottom, is formed in at least one of a contact surface of a rotor and a contact surface of an armature. A solid material, which is made of thermoset resin that contains powder of metal oxide or metal dispersed in the thermoset resin, is formed in an inside of the recess.

Abstract: When a clutch relay connects between a control device and a vehicle electric power source in response to outputting of a clutch OFF signal from an electronic control device to the clutch relay, a timer circuit starts a control operation for energizing coil portions. When a predetermined time period elapses, the timer circuit terminates energization of the coil portions. When the clutch relay connects between the control device and the vehicle electric power source in response to outputting of a clutch ON signal from the electronic control device to the relay, the timer circuit starts a control operation for energizing the coil portions. When a predetermined time period elapses, the timer circuit terminates energization of the coil portions.

Abstract: A ring insertion groove is formed between adjacent two of circular plates, which are made of a magnetic material and are arranged concentric with each other, and a ring, which is made of a non-magnetic material and has a larger deformation resistance in comparison to the magnetic material of the plates, is press fitted into the ring insertion groove. Thereafter, a peripheral part around an opening of the ring insertion groove is plastically flowed, so that a compression stress is left in the ring.

Abstract: In a clutch mechanism, non-magnetic portions of an armature and non-magnetic portions of a pulley are offset from one another in a radial direction of a rotating shaft. For this reason, in an attracting magnetic circuit, magnetic flux passes between an outer cylindrical portion and an inner cylindrical portion so as to avoid the non-magnetic portions of the armature and the non-magnetic portions of the pulley. Accordingly, magnetic flux passes through a boundary between the armature and the pulley six times. The number of poles of the attracting magnetic circuit is increased. The physical size of a permanent magnet can be reduced. For this reason, the physical size of the clutch mechanism is reduced. As a result, the power consumption of an electromagnetic coil can be reduced by increasing the cross-sectional areas of coil portions. The physical size of the clutch mechanism is reduced and the power consumed is reduced.

Abstract: A recess, which has a bottom, is formed in at least one of a contact surface of a rotor and a contact surface of an armature. A solid material, which is made of thermoset resin that contains powder of metal oxide or metal dispersed in the thermoset resin, is formed in an inside of the recess.

Abstract: When a control unit starts to supply power to an electromagnetic coil in a first direction, a magnetic force generated by a non-attracting magnetic circuit becomes larger than a magnetic attraction force generated by an attracting magnetic circuit. As a result, a movable member is guided by a guide portion of a yoke and moves to a second position from a first position. When the control unit starts to supply power to an electromagnetic coil in a second direction, the magnetic attraction force generated by the attracting magnetic circuit becomes larger than the magnetic force generated by the non-attracting magnetic circuit. As a result, the movable member is guided by the guide portion and moves to the first position from the second position. Accordingly, the movable member can reliably perform a moving operation when turning ON/OFF.

Abstract: When a pulley and an armature are coupled with each other, first and second permanent magnets place the movable member at a location where a magnetic resistance of an attracting magnetic circuit, which generates an attracting magnetic force to couple between the pulley and the armature, is reduced. In contrast, when the pulley and the armature are decoupled from each other, the movable member is placed at a location where the magnetic resistance of the attracting magnetic circuit is increased, and a magnetic resistance of a non-attracting magnetic circuit is reduced. Thereby, a coupled state or a decoupled state of the pulley and the armature can be maintained without an erroneous operation.

Abstract: To reduce running cost while preventing production of noise. Provided are a pair of magnetic meshing rings (151) including magnetic meshing teeth (151b) arranged side by side on both an inner circumferential surface and an outer circumferential surface of a middle yoke member (15); a magnet member (152) situated between the pair of the magnetic meshing rings (151) such that the magnetic meshing teeth on one of the magnetic meshing rings (151) and magnetic meshing teeth on the other one of the magnetic meshing rings (151) have opposite magnetic poles; and a pair of meshing tooth rows (25) including a plurality of meshing teeth (25a) arranged side by side on an outer circumferential surface of an inner yoke member (21) and on an inner circumferential surface of an outer yoke member (22) and facing the magnetic meshing rings (151), the meshing tooth rows (25) being disposed at portions where the meshing tooth rows (25) face the inner and outer circumferential surfaces of the middle yoke member (15).

Abstract: When a pulley and an armature are coupled with each other, first and second permanent magnets place the movable member at a location where a magnetic resistance of an attracting magnetic circuit, which generates an attracting magnetic force to couple between the pulley and the armature, is reduced. In contrast, when the pulley and the armature are decoupled from each other, the movable member is placed at a location where the magnetic resistance of the attracting magnetic circuit is increased, and a magnetic resistance of a non-attracting magnetic circuit is reduced. Thereby, a coupled state or a decoupled state of the pulley and the armature can be maintained without an erroneous operation.

Abstract: The heat retaining article according to the invention comprises at least one inflatable envelope attached on a sheet material. The envelope is made of an air-impermeable sheet which is produced by treating a cloth with at least one synthetic or natural rubber. The heat retaining property of the article can be controlled by adjusting the amount of air filled in the envelope.