Pumps – Three or more cylinders arranged in parallel – radial – or...
Reexamination Certificate
1999-03-30
2001-06-26
Walberg, Teresa (Department: 3742)
Pumps
Three or more cylinders arranged in parallel, radial, or...
Reexamination Certificate
active
06250892
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to refrigerant suction structures for a compressor. More particularly, the present invention relates to refrigerant suction structures for a compressor in which a plurality of suction ports are formed in a partition plate which separates a plurality of cylinder bores arranged in a circular form around a longitudinal axis of a rotary shaft from a suction chamber. Compressing elements fitted in the cylinder bores are caused to move by rotating motion of the rotary shaft, and a refrigerant is introduced from the suction chamber into the individual cylinder bores through the suction ports. Refrigerant is expelled from the cylinder bores into a discharge chamber formed around the outer periphery of the suction chamber as a result of movements of the compressing elements.
2. Description of the Related Art
In a compressor disclosed in Japanese Unexamined Patent Publication No. 56-69476, a cam plate compartment accommodating a cam plate constitutes part of a suction passage and a refrigerant taken into the cam plate compartment is introduced into a suction chamber formed in a housing which extends from the front to the rear of a cylinder block. The refrigerant in the suction chamber is drawn into cylinder bores through suction holes formed in a side plate with a suction action of each piston, and the refrigerant in the cylinder bores is driven out into a discharge chamber in the housing through discharge holes formed in the side plate with a discharge action of each piston.
In this example of prior art technology, the discharge chamber surrounds the outer periphery of the suction chamber and the refrigerant in the cam plate compartment is introduced into the suction chamber through the holes in the side plate. The suction passage extending from the outside of the compressor to the cylinder bores is bent or curved, and such meandering part of the suction passage causes pressure loss. The pressure loss in the suction passage impedes smooth introduction of the refrigerant into the cylinder bores, resulting in a reduction in volumetric efficiency with respect to the refrigerant.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide refrigerant suction structures which can reduce pressure loss in a suction passage running from the outside of a compressor to its cylinder bores.
The refrigerant suction structures of the invention are intended to be incorporated in a compressor in which a plurality of suction ports are formed in a partition plate which separates a plurality of cylinder bores arranged in a circular form around a longitudinal axis of a rotary shaft from a suction chamber. Compressing elements fitted in the cylinder bores are caused to move by rotating motion of the rotary shaft, and a refrigerant is introduced from the suction chamber into the individual cylinder bores through the suction ports. Refrigerant is expelled from the cylinder bores into a discharge chamber formed around the outer periphery of the suction chamber as a result of movements of the compressing elements.
According to a principal aspect of the invention, a refrigerant feeder for feeding a suction chamber with a gaseous refrigerant to be compressed is formed so as to extend across the discharge chamber and to open into the suction chamber from an outer periphery of the suction chamber.
This makes it possible to form the refrigerant feeder channel running from the outside of the compressor to the suction chamber in a straight or substantially straight line. This structure of the refrigerant feeder channel helps decrease pressure loss in a suction passage inside the compressor that connects an external refrigerant circuit to the suction chamber.
In another aspect of the invention, the refrigerant feeder channel projects from a side wall of the suction chamber with an outflow opening of the refrigerant feeder channel directed toward the center of a circle along which the suction ports are arranged in the circular form.
This structure employing the refrigerant feeder channel projecting from the side wall of the suction chamber helps decrease differences in the distances from the individual suction ports to the outflow opening of the refrigerant feeder channel and uniformly reduce the pressure loss when the refrigerant flows into the individual cylinder bores.
In still another aspect of the invention, the outflow opening of the refrigerant feeder channel is provided at a position corresponding to the center of the circle along which the suction ports are arranged in the circular form.
In this structure, the distances from the individual suction ports to the outflow opening of the refrigerant feeder channel become nearly the same and pressure variations at the outflow opening are minimized. This helps reduce acoustic noise caused by suction pressure pulsation which would be transmitted through the refrigerant feeder channel to the external refrigerant circuit.
In yet another aspect of the invention, the outflow opening of the refrigerant feeder channel has a slanting edge so that it opens toward the partition plate.
The slanting edge of the outflow opening serves to reduce the pressure loss.
In a further aspect of the invention, the refrigerant feeder channel is formed along an inside surface of a rear wall of the suction chamber.
This construction of the refrigerant feeder channel is effective for minimizing the pressure loss.
In a still further aspect of the invention, a structural wall of the refrigerant feeder channel is formed as an integral part of the rear wall of the suction chamber.
This kind of one-piece construction is advantageous from the viewpoint of case of manufacture and production cost.
In a further aspect of the invention, there are formed a plurality of retaining projections on the inside surface of the rear wall of the suction chamber. These retaining projections are arranged in a circular configuration and press the partition plate toward the cylinder bores. The outflow opening of the refrigerant feeder channel is provided inside a circle along which the retaining projections are arranged so that no retaining projections are located between the outflow opening and the individual suction ports.
A pushing force exerted by the multiple retaining projections prevents leakage of the refrigerant from the cylinder bores along the partition plate. This structure in which the outflow opening of the refrigerant feeder channel is located inside the circle along which the retaining projections are arranged reduces the influence of the retaining projections on the flow of the refrigerant from the outflow opening to the suction ports.
In a further aspect of the invention, there is formed a swollen part bulging out into the suction chamber on its rear wall in such a way that an area of the inside surface of the rear wall of the suction chamber extended from the refrigerant feeder channel intersects the swollen part.
The swollen part serves to smooth out refrigerant streams flowing from the outflow opening of the refrigerant feeder channel to the suction ports.
In another aspect of the invention, the compressor is a variable displacement compressor in which the refrigerant is supplied from a discharge pressure region to a controlled pressure chamber and drawn out of the controlled pressure chamber into a suction pressure region, and the displacement capacity of the compressor is varied according to the difference between controlled pressure in the controlled pressure chamber and suction pressure in the suction pressure region, wherein a capacity control valve is used for controlling operation at least for supplying the refrigerant from the discharge pressure region to the controlled pressure chamber or for drawing out the refrigerant from the controlled pressure chamber into the suction pressure region.
The present invention is preferable for embodying in this kind of variable displacement compressor.
In a further aspect of the invention, the capacity control valve is accommodated in a compartment form
Kato Keiichi
Kurakake Hirotaka
Kurita Hajime
Ota Masaki
Fitzpatrick ,Cella, Harper & Scinto
Patel Vinod D.
Toyoda Automatic Loom Works, Ltd.
Walberg Teresa
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