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Refrigerating cycle device and sealed-type rotary compressor

This is a Continuation Application of PCT Application No. PCT/JP2005/023031, filed Dec. 15, 2005, which was published under PCT Article 21(2) in Japanese.

This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2005-000226, filed Jan. 4, 2005, the entire contents of which are incorporated herein by reference.

1. Field of the Invention

The present invention relates to a refrigerating cycle device equipped with a sealed-type rotary compressor that switches one of multiple compressor mechanisms to operate or stop operating in accordance with the magnitude of load, and the sealed-type rotary compressor.

2. Description of the Related Art

A general sealed-type rotary compressor is configured in an in-casing high-pressure type, in which an electric motor and a rotary-type compressor mechanism that is linked to this electric motor are housed in a sealed casing, and gas compressed at the compressor mechanism is temporarily discharged into the sealed casing.

The compressor mechanism has an eccentric roller housed in a cylinder chamber formed in a cylinder, and the head end edge of a vane constantly comes elastically into contact with the circumferential surface of the eccentric roller. The cylinder chamber is divided into two chambers by the vane, and a suction unit communicates with one chamber, while a discharge unit communicates with the other chamber. A suction pipe is connected to the suction unit and the discharge unit is open to the sealed casing.

In recent years, a two-cylinder-type sealed rotary compressor, with two sets of compressor mechanisms set above and below, has been standardized. In this kind of a compressor, if there can be provided a compressor mechanism which constantly carries out compression operation and a compressor mechanism which can switch between compression operation and operation stop in accordance with the magnitude of load, the specifications are advantageously expanded.

For example, Jpn. Pat. Appln. KOKAI Publication No. 1-247786 (Patent Document 1) discloses a technique related to a compressor having two cylinder chambers and equipped with high-pressure introducing means for forcibly separating and holding a vane of either one of the cylinder chambers from a roller as required and pressurizing the cylinder chamber to interrupt compression action.

In addition, Japanese Patent No. 2803456 (Patent Document 2) discloses a technique related to a compressor having a bypass passage serving as means for introducing high pressure from a sealed container to a suction pipe, in which in one cylinder chamber a vane is brought in contact with a roller by the action of an elastic member even at the time of off-cylinder operation in which no compression action takes place and a compression chamber is constantly partitioned by the vane.

Note that, the compressor according to Patent Document 1 is functionally excellent, but in order to configure high-pressure introducing means, it includes a high-pressure introducing hole which communicates one cylinder chamber with the sealed casing, a two-stage restriction mechanism provided to a refrigerating cycle, and a bypass refrigerant pipe which is branched from the intermediate portion of this restriction mechanism, which communicates with a vane chamber of one side, and which is equipped with an electromagnetic open-close valve in the middle portion thereof.

That is, boring processing to provide the high-pressure introducing means to the compressor is required, and at the same time, the restrictor on the refrigerating cycle must be made into a two-stage restrictor. Furthermore, a bypass refrigerant pipe must be connected between this two-stage restrictor and the cylinder chamber to increase complication of the configuration, which adversely affects the cost.

Furthermore, in the compressor according to Patent Document 2, a bypass pipe connection process to bypass the discharge side and the suction side to the sealed container must be performed, and this adversely affects the cost. Further, because the vane is constantly brought elastically in contact with the roller even during the off-cylinder operation, there occurs a failure that the efficiency is lowered due to the presence of a little compression work or sliding loss.

In both techniques, when the high-pressure introducing means is operated and high pressure is introduced to a predetermined compressor mechanism, there is a fear that the high-pressure refrigerant flows backward from the suction pipe connected to the compressor to an accumulator. However, no specific structure to prevent backflow is described in either Patent Document.

The present invention is made on the basis of the above situation and an object of the present invention is to provide a refrigerating cycle device which has pressure switching means to one compressor mechanism that forms a sealed-type rotary compressor to enable switching between compression operation and operation stop in accordance with the magnitude of load, and which prevents backflow of the refrigerant to the accumulator and prevents detrimental thermal effect in providing the pressure switching means to secure reliability, and the sealed-type rotary compressor.

The present invention has been achieved in order to satisfy the object, and comprises: a sealed-type rotary compressor which houses an electric motor unit and multiple sets of rotary compressor mechanisms connected to the electric motor unit in a sealed casing, which suctions a refrigerant from an accumulator provided outside the sealed casing via suction pipes, respectively, to each of the compressor mechanisms, which compresses the refrigerant at each compressor mechanism, and then, discharges the refrigerant via a space in the sealed casing; a refrigerating cycle circuit composed of this sealed-type rotary compressor and refrigerating cycle components which are linked to communicate via a refrigerant pipe; and pressure switching means switching one of the compressor mechanisms in such a manner that low-pressure gas is guided to the compressor mechanism in the sealed-type rotary compressor to allow it to conduct regular compression operation or high-pressure gas is guided thereto to allow it to stop compression operation in accordance with the magnitude of load, wherein the pressure switching means comprises: a branch pipe, one end of which is connected to a high pressure side of the refrigerating cycle via an electromagnetic open-close valve and the other end of which is connected to a suction pipe which communicates the accumulator to the other compressor mechanism; an auxiliary suction pipe connected to an end part protruding to the inside of the accumulator of the suction pipe; a check valve which is mounted on the auxiliary suction pipe or the suction pipe and which checks reverse flow of refrigerant to the accumulator; and a guide pipe which mounts and holds the suction pipe or the auxiliary suction pipe to the accumulator.

And a sealed-type rotary compressor which houses an electric motor unit and multiple sets of rotary compressor mechanisms to be connected to this electric motor unit in a sealed housing, which suctions a refrigerant from an accumulator provided outside the sealed casing via suction pipes, respectively, to each of the compressor mechanisms, and which compresses the refrigerant in each compressor mechanism, and then, discharges the refrigerant via a space in the sealed casing, the compressor comprising pressure switching means having: a branch pipe, one end of which is connected to a high pressure side of the refrigerating cycle via an electromagnetic open-close valve and the other end of which is connected to a suction pipe which communicates the accumulator to the other compressor mechanism; an auxiliary suction pipe connected to an end part protruding to the inside of the accumulator of the suction pipe; a check valve which is mounted on the auxiliary suction pipe or the suction pipe and which checks reverse flow of refrigerant to the accumulator; and a guide pipe which mounts and holds the suction pipe or the auxiliary suction pipe to the accumulator.