Abstract: A control unit for variable displacement compressors is used for two independent air conditioning cycles, wherein two compressors 1, 11 driven by a common external drive source 8 include electromagnetic displacement control valves 6, 16, respectively. By controlling these control valves by ECU 7, the displacement of the compressor is variable. When the air temperature is higher than a predetermined temperature T0, both of the compressors are subjected to the variable displacement operation even though one of them is unnecessary for the air conditioning operation. On the contrary, if the outer air temperature is lower than the predetermined temperature, only one compressor, needed for the air conditioning operation, is subjected to the variable displacement operation, while the other compressor is subjected to the minimum displacement operation.

Abstract: A compressor device for a refrigerant cycle includes a compressor and a control unit. The compressor is provided with a displacement changing mechanism for changing its displacement. The control unit changes a current value supplied to the displacement changing mechanism, thereby relatively changing the displacement of the compressor. In the compressor device, when a rotational speed of a vehicle engine is lower than a predetermined rotational speed, the control unit controls an upper limit of the current value between a first predetermined value and a maximum value. Accordingly, a displacement specification of the compressor device can be normalized for vehicle engines having different power outputs, while engine stall can be prevented.

Abstract: A plate 13e, the outer diameter side of which is fixed to be integral with a plate section 13c, and which is provided with an engagement part 13g to be engaged with a shoulder 13f formed on the inner diameter side of a boss section 13a, is integral with a center hub 13. Thereby, even if a bridge section 13d is broken and the plate section 13c moves in the detachment direction of the center hub 13, the engagement part 13g of the plate 13e is engaged with the shoulder 13f of the boss section 13a, whereby the plate section 13c and the boss section 13a are engaged and coupled with each other while interrupting the torque transmission. Accordingly, even if the bridge section 13d is broken, the boss section 13a as well as the plate section 13c side are prevented from being detached from a pulley 10.

Abstract: The screw engagement portion (10) between the pulley (9) (the boss (9g)) and the shaft (1a) is provided with a thread in a direction to increase the tightening torque when the pulley (9) is driven. A breakable part (1i) which is broken by the axial tension produced in accordance with the tightening, when the tightening torque acting on the screw engagement portion (10) is above a predetermined value, is also provided. With this structure, the stress to break the breakable part (1i) is not a shearing stress but is mainly a tensile stress. Unlike the shearing stress, the tensile stress is substantially uniformly distributed in a cross section and, hence, the stress distribution of the breakable part (1i) can be relatively precisely predicted and analyzed. Consequently, the necessity of determining the dimension and the material, etc. of the breakable part (1i) by trial and error is reduced, thus leading to facilitation of the design and development.

Abstract: When a first damper contacts both of a protruding portion of a pulley body and a protruding portion of a center hub, a second damper is disposed as being apart from the protruding portion of the center hub with a gap. Even when the pulley body is rotated in a reverse direction, no reverse torque is thereby transmitted to the center hub as long as the gap exists, or before the second damper contacts the protruding portion of the center hub. As a result, torque fluctuation is sufficiently absorbed. This prevents the following: a reverse torque is transmitted to the center hub; a torque limiter wrongly acts; a fastening part between a shaft and the center hub loosens; or abnormal noise or aversive vibration takes place.

Abstract: A compressor device for a refrigerant cycle includes a compressor and a control unit. The compressor is provided with a displacement changing mechanism for changing its displacement. The control unit changes a current value supplied to the displacement changing mechanism, thereby relatively changing the displacement of the compressor. In the compressor device, when a rotational speed of a vehicle engine is lower than a predetermined rotational speed, the control unit controls an upper limit of the current value between a first predetermined value and a maximum value. Accordingly, a displacement specification of the compressor device can be normalized for vehicle engines having different power outputs, while engine stall can be prevented.

Abstract: A power transmission device which interrupts torque transmission when the torque exceeds a predetermined torque. A torque limiter includes projections formed on a center hub and a pulley. The center hub includes bridges that transmit torque by a pulling force. When a preset torque limit is reached, the projections on the center hub make contact with and move along slanted faces so as to move the center hub in an axial direction relative to the pulley. The bridges are thereby subjected to a bending moment in addition to the pulling force when the torque exceeds the preset torque level, so that the bridges break precisely above the preset torque level due to the reduced fatigue limit.

Abstract: A control unit for variable displacement compressors is used for two independent air conditioning cycles, wherein two compressors 1, 11 driven by a common external drive source 8 include electromagnetic displacement control valves 6, 16, respectively. By controlling these control valves by ECU 7, the displacement of the compressor is variable. When the air temperature is higher than a predetermined temperature To, both of the compressors are subjected to the variable displacement operation even though one of them is unnecessary for the air conditioning operation. On the contrary, if the outer air temperature is lower than the predetermined temperature, only one compressor, needed for the air conditioning operation, is subjected to the variable displacement operation, while the other compressor is subjected to the minimum displacement operation.

Abstract: An improved displacement control valve incorporated in a variable displacement compressor. The control valve includes a valve body and a solenoid for actuating the valve body. The coil of the solenoid is wound about a bobbin made of insulating synthetic resin. A base plate integrally protrudes from the bobbin. A pair of conducting plates are secured to the base plate. Each plate has a clamping block. The coil has a pair of terminal wires. Each terminal wire is secured to and electrically corrected to one of the clamping blocks. Each terminal wire is wound about a holder formed in each plate between the bobbin and the corresponding clamping block. A diode is secured to the holders and is connected in parallel with the coil. A pair of terminals of the diode are secured to the corresponding holders by soldering and crimping. The holders prevent tension in the terminal wires from being applied to electrical joints formed between the wires and the clamping blocks, which makes the valve more reliable.

Abstract: A fuel vapor treatment apparatus for a vehicle for absorbing the fuel vapor emanating from a fuel tank has a diffusing chamber at the portion into which an inlet port opens. The fuel vapor introduced through the inlet port diffuses in this diffusing chamber, by which the component of the fuel vapor velocity in the direction in which the fuel vapor is adsorbed by the adsorbent is reduced. In consequence, the capability with which the canister adsorbs the fuel vapor is increased so as to allow a large volume of fuel vapor which flows at a high flow rate to be adsorbed.