192 clutches and power-stop control – Clutches – Operators
Reexamination Certificate
2001-07-10
2003-06-24
Bonck, Rodney H. (Department: 3681)
192 clutches and power-stop control
Clutches
Operators
C192S08100C
Reexamination Certificate
active
06581743
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to electromagnetic spring clutches that preferably may be utilized to intermittently drive auxiliary machines for vehicle, such as the water pump, compressor and viscous heater disclosed, for example, in DE 3,147,468. More particularly, the present invention relates to electromagnetic spring clutches that may preferably transmit torque from an automotive engine to the auxiliary machines for vehicle by utilizing a coil spring.
2. Description of the Related Art
A known-electromagnetic spring clutch is disclosed in Japanese Laid-Open Patent Publication No. 58-193939 and includes an electromagnetic coil disposed within an input pulley that is driven by an engine. An armature is disposed at an output hub that is coupled to a rotary shaft of an auxiliary machine for vehicle. The armature is attached to and removed from the input pulley by energizing and de-energizing the electromagnetic coil. The known electromagnetic spring clutch further includes a coil spring mounted around the outer circumference of an input-side winding portion provided on the input pulley and the outer circumference of an output-side winding portion provided on the output hub. One end of the coil spring is coupled to the armature and the other end of the coil spring is coupled to the output hub. When the armature is magnetically coupled to the input pulley by the electromagnetic coil, the coil spring winds onto the input-side winding of the input pulley and onto the output-side winding of the output hub. As the result, torque from the input pulley is transmitted to the output hub and thus to the rotary shaft of the auxiliary machine for vehicle due to the winding force of the coil spring.
The input-side winding portion of the input pulley and the output-side winding portion of the output hub are separated by a minute clearance. The width of the clearance normally does not allow the coil spring to intrude into the clearance. However, when the coil spring wraps around the outer circumference of the input-side winding portion and the output-side winding portion in order to transmit torque, a force is exerted on the inner circumference of the coil spring, which force widens the clearance. When the clearance is widened, the coil spring may possibly intrude into the clearance and prevent the smooth operation of the electromagnetic spring clutch.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide improved electromagnetic spring clutches. In one embodiment of the present electromagnetic spring clutches, the coil spring is prevented from intruding or entering into the clearance between an input-side winding portion and an output-side winding portion during the transmission of torque.
For example, electromagnetic spring clutches of the present teachings may be preferably utilized with a driven device, such as a water pump, compressor or other auxiliary machine for vehicle, that is driven by a rotary or drive shaft. Such electromagnetic spring clutches may include an input-side member, such as an input pulley, and an output-side member, such as an output hub, which parts may be reversibly coupled by an armature and a coil spring. For example, the armature can be attached to and removed from the input-side member by energizing and de-energizing an electromagnetic coil. Further, the coil spring preferably extends from the outer circumference of the input-side member to the outer circumference of the output-side member. In addition, one end of the coil spring is preferably coupled to the armature and the other end of the coil spring is preferably coupled to the output-side member. Thus, when the input-side member and the output-side member are magnetically coupled via the armature, the output-side member will transmit a driving force to the rotary shaft of the driven device. More preferably, the output-side member and the rotary shaft are prevented from moving relative to each other in the axial direction in order to restrict movement of the output-side member along its axial direction. Thus, the relative position of the input-side member and the output-side member will not change during operation. As the result, the coil spring is prevented from intruding into the clearance between the input-side member and the output-side member.
Other objects, features and advantage of the present invention will be readily understood after reading the following detailed description together with the accompanying drawings and the claims.
REFERENCES:
patent: 2979925 (1961-04-01), Hungerford
patent: 3735847 (1973-05-01), Brucken
patent: 4262787 (1981-04-01), Takefuta et al.
patent: 4273226 (1981-06-01), Takefuta et al.
patent: 4466522 (1984-08-01), Shibuya
patent: 4619351 (1986-10-01), Takatoshi
patent: 5090538 (1992-02-01), Osawa
patent: 6247569 (2001-06-01), McGuire et al.
patent: 6352416 (2002-03-01), Ota et al.
patent: 31 47 468 (1982-12-01), None
patent: 58-193939 (1983-11-01), None
patent: 6-73464 (1994-10-01), None
patent: 10-068434 (1998-03-01), None
Moroi Takahiro
Niwa Masami
Suzuki Shigeru
Bonck Rodney H.
Kabushiki Kaisha Toyoda Jidoshokki Seisakusho
Morgan & Finnegan , LLP
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