| 摘要 |
PURPOSE:To provide a four-way reversing valve for reversible refrigerating cycle which may be quickly switched from a heating operation to a cooling operation, by providing an auxiliary return spring operable in the heating operation only. CONSTITUTION:When a solenoid valve 16 is energized and a compressor 4 is started in a cooling operation, a plunger 17 is attracted, and a needle valve 18 opens a pressure relief hole 3a to communicate a pressure converting chamber R2 with a low-pressure suction side of the compressor 4. As a result, the pressure in the pressure converting chamber R2 is reduced, and therefore, there is generated a pressure differential greater than a resilient force of a compression spring 13 between chambers R1 and R2, thereby starting to move a piston 12 and a slide valve 21 toward a plug 3. Accordingly, an auxiliary return spring 12g is compressed to close a pressure balancing hole 12a, then stopping the cooling operation and being switched to a heating operation. In the heating operation, when the compressor 4 is stopped by a thermostat, pressure on the high pressure side and that on the low pressure side are gradually balanced to reach a maximum operational pressure differential. Then, the piston starts to be moved relatively quickly by resilient forces of the compression spring 13 and the auxiliary return spring 12g. Thus, the heating operation is switched to a cooling operation.
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