Pumps – Three or more cylinders arranged in parallel – radial – or...
Reexamination Certificate
1999-05-26
2001-05-08
Walberg, Teresa (Department: 3742)
Pumps
Three or more cylinders arranged in parallel, radial, or...
C417S222100
Reexamination Certificate
active
06227814
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a reciprocating type refrigerant compressor improved so as to prevent leakage of a compressed refrigerant from the cylinder bores in which compression of the refrigerant is carried out by the reciprocation of pistons. More particularly, the present invention relates to an improved internal sealing unit interposed between an end of a cylinder block and a valve plate assembly of a reciprocating type refrigerant compressor in order to tightly seal the periphery of each of a plurality of cylinder bores in which respective pistons reciprocate to suck a refrigerant from a suction chamber, compress the refrigerant, and discharge the compressed refrigerant into a discharge chamber. The reciprocating type refrigerant compressor according to the present invention is intended to be used as a refrigerant compressor incorporated in a vehicle climate control system.
2. Description of the Related Art
U.S. Pat. No. 4,688,997 to Suzuki et al. discloses one of the typical reciprocating refrigerant compressors adapted for use in a vehicle climate control system. The reciprocating refrigerant compressor includes a cylinder block having formed therein a plurality of parallel cylinder bores arranged around an axis of rotation of a drive shaft rotatably supported by the cylinder block and a housing assembly closing the opposite ends of the cylinder block, a valve plate having bored therein a plurality of suction ports and a plurality of discharge ports arranged to open into the respective cylinder bores, a suction chamber, a discharge chamber and, a crank chamber which are defined in the housing assembly, a suction valve interposed between one end of the cylinder block and the valve plate, a discharge valve interposed between the valve plate and the housing assembly, and a plurality of single-headed pistons reciprocating in the cylinder bores for the compression of a refrigerant sucked from the suction chamber and for the discharge of the compressed refrigerant into the discharge chamber. Namely, in the reciprocating refrigerant compressor, the plurality of pistons reciprocate in the cylinder bores in response to the rotation of a cam plate and the drive shaft within the crank chamber and, accordingly, the refrigerant at low temperature and pressure which has entered from an external refrigerating circuit into the suction chamber is sucked into the respective cylinder bores via the suction ports to be compressed by the pistons in the compression chambers formed in the respective cylinder bores. The compressed refrigerant is discharged as the refrigerant gas at high temperature and pressure by the pistons from the compression chambers into the discharge chamber via the discharge ports. The compressed refrigerant is further delivered from the discharge chamber into the external refrigerating circuit of the climate control system.
When the refrigerant is compressed by the pistons within the compression chambers in the respective cylinder bores, the refrigerant at high pressure should be discharged from the compression chambers into only the discharge chamber while being prevented from leaking into a suction pressure area or an exterior of the compressor via an end face area of the cylinder block surrounding the respective cylinder bores. The leakage of the compressed refrigerant reduces the amount of the compressed refrigerant to be used with the climate control system, and therefore, the compressing performance of the refrigerant compressor decreases. Thus, the end of the cylinder block must be appropriately sealed.
The sealing of the cylinder block end and, particularly, the end face area surrounding the respective cylinder bores of the cylinder block, to prevent the leakage of the compressed refrigerant acquires a great importance to the reciprocating refrigerant compressors used with a supercritical-cycle-refrigerating system in which a closed refrigerant-circulation path thereof includes a high-pressure path through which the refrigerant under a high discharge pressure, more specifically, under an supercritical pressure flows.
In the refrigerant compressor incorporated in the super-critical-cycle refrigerating system, the gas of the refrigerant is compressed to have a pressure high above a critical pressure peculiar to the refrigerant. For example, when a carbon dioxide of which the critical pressure is 7.35 MPa is used as a refrigerant, the compressor compresses the refrigerant to a pressure of approximately 10 MPa.
On the other hand, when a fluorinated hydrocarbon gas is used as the refrigerant, and when the refrigerant compressor is incorporated in a refrigerating system operated under a condition such that a discharge pressure and a suction pressure of the refrigerant gas are always kept below a critical pressure of the refrigerant gas (this type of refrigerating system will be hereinafter referred to as a subcritical-cycle-type refrigerating system), the discharge pressure of the refrigerant discharged from the compression chambers of the compressor is approximately 1 through 3 MPa.
Therefore, it will be understood that the discharge pressure of the compressor incorporated in the supercritical-cycle-type refrigerating system is much higher than that of the compressor incorporated in the subcritical-cycle-type refrigerating system.
Accordingly, the sealing of the end face area of the cylinder block around the respective cylinder bores is very critical to the reciprocating refrigerant compressor which is used with the supercritical-cycle-type refrigerating system, in order to prevent leakage of the compressed refrigerant from the cylinder bores into the suction pressure region in the compressor or the exterior of the compressor, via a boundary between the end face area of the cylinder block around the cylinder bores and the confronting face of the valve plate.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a reciprocating refrigerant compressor with a sealing unit capable of surely preventing leakage of the refrigerant at a high pressure from respective cylinder bores into non-desired region inside or outside the compressor.
Another object of the present invention is to provide a sealing unit suitable for sealing an end face of a cylinder block at an area surrounding bore ends of the cylinder bores of a reciprocating refrigerant compressor, which is used for compressing a refrigerant to a pressure far above a critical pressure of the refrigerant, and for preventing leakage of the compressed refrigerant from the cylinder bores into non-desired region inside or outside the compressor such as the suction pressure area or the exterior of the compressor to thereby prevent a reduction in the compressing performance of the compressor.
A further object of the present invention is to provide a reciprocating refrigerant compressor provided with a sealing unit, which permits the compressor to employ a carbon dioxide as a refrigerant and to be used with a supercritical-cycle-type refrigerating system.
In accordance with the present invention, there is provided a reciprocating refrigerant compressor which comprises:
a cylinder block having formed therein a plurality of cylinder bores arranged to be parallel with one another around an axis extending between opposite ends of the cylinder block;
a valve plate arranged adjacent to the cylinder block and having bored therein a plurality of suction ports and a plurality of discharge ports which are respectively arranged to be in registration with the cylinder bores;
a housing assembly assembled to the cylinder block to close the opposite ends of the cylinder block and defining a suction chamber, a discharge chamber, and a crank chamber;
a suction valve interposed between one of the opposite ends of the cylinder block and the valve plate;
a discharge valve interposed between the valve plate and an end of the housing assembly;
a plurality of pistons arranged to be reciprocated in the plurality of cylinder bores for the compression of a refrig
Koide Tatsuya
Murakami Kazuo
Yokomachi Naoya
Kabushiki Kaisha Toyoda Jidoshokki Seisakusho
Robinson Daniel
Walberg Teresa
Woodcock Washburn Kurtz Mackiewicz & Norris LLP
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