Pumps – With condition responsive pumped fluid control – Pressure responsive relief or bypass valve
Reexamination Certificate
1999-01-26
2001-01-23
Thorpe, Timothy S. (Department: 3746)
Pumps
With condition responsive pumped fluid control
Pressure responsive relief or bypass valve
C417S299000, C417S440000, C417S295000, C417S308000, C418S055100, C418S055400, C418S055500, C062S505000
Reexamination Certificate
active
06176685
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates in general to a scroll compressor and more particularly to a chock reduction mechanism for reducing a shock at the time of starting of the compressor.
A scroll compressor having a shock reduction mechanism has been used for air conditioners in automotive vehicles. In general, the air conditioner for automobiles is driven by an engine of the automobiles by way of an electromagnetic clutch and a belt so that driving and stop of the air conditioner is selected by an on-off operation of the electromagnetic clutch. Therefore, shocks are added to a body of the automobile due to a load variation at the starting time of the air conditioner and, consequently, a riding comfort is spoiled. Thus, an attempt has been sought to restrict or lessen the load variation at the starting time and to lessen a shock received by the body of the automobile.
An attempt is made to overcome the shortcomings described above by providing a new mechanism for a scroll compressor, as disclosed in JP-A-7-324690 in which the scroll compressor has, on an end plate of a fixed scroll member, a cylinder extending in a radial direction and a bypass channel which connects the cylinder with an operation chamber or a compression space. The cylinder is provided with a spool valve to displace the spool valve within the cylinder by the use of a pressure difference, so that a refrigerant gas which is in the midst of compression at the starting time is returned to a suction chamber through the bypass channel and the cylinder. This permits reduction of volume of the compressor at the starting time and, therefore, the load difference at the starting time can be reduced.
However, the scroll compressor suggested by JP-A-7-324690 involves some problems that a compression load is generated by a compression loss because of utilization of the by-pass channel provided for the purpose of returning the refrigerant gas into the suction chamber and, therefore, a reduction effect of a shock to the vehicle body is limited to a low level. Further, in order to reduce a pressure loss at the by-pass chamber, the size of the spool valve and the cylinder must be designed to be large enough and, accordingly, this results in a large-size fixed scroll member and finally a large scaled entire structure of the scroll compressor. Besides the above, when the discharge pressure which provides a pressure difference for driving the spool valve results in a pressure variation as pulsation or the like, it is likely that the spool valve is driven out of the predetermination. Consequently, there are cases that the reduction effect of shock to the vehicle body is lowered.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a scroll compressor which permits to reduce a load variation at the starting time of the compressor without involvement of problems of a pressure loss and larger/heavy structure.
It is another object of the present invention to provide a scroll compressor of the type described, in which communication is controlled between adjacent compression spaces so as to enable variable displacement in the scroll compressor.
Other objects of the present invention will become clear as the description proceeds.
A scroll compressor to which the present invention is applied comprises a fixed scroll member and a movable scroll member which define a plurality of compression spaces therebetween in cooperation with each other. The compression spaces are movable with volumes reduced by movement of the movable scroll member. The scroll compressor further comprises a hole defining surface formed to the fixed scroll member for defining a hole communicable with adjacent ones of the compression spaces. The adjacent ones are different from each other in pressure when the scroll compressor is driven. The scroll compressor further comprises a valve member disposed in the hole for controlling communication between the adjacent ones through the hole.
According to an aspect of the present invention, there is provided a scroll compressor which comprises a fixed scroll member having an end plate, a movable scroll member eccentrically spaced from the fixed scroll member and having an end plate, a compression space formed between the fixed scroll member and the movable scroll member, the compression space being movable with its volume reduced by an orbiting movement of the movable scroll member, a cylinder channel provided on the end plate of the fixed scroll member and capable of being connected with the compression space, and a piston valve disposed in the cylinder channel such that the piston valve is movable between a first position contacted with an upper surface of an involute portion of the movable scroll member and a second position spaced from the first position, a fluid in the compression space being permitted to flow into a low pressure space between the movable scroll member and the fixed scroll member through the cylinder channel when the piston valve is position in the second position.
According to another aspect of the present invention, there is provided a scroll compressor which comprises a fixed scroll member having an end plate, a movable scroll member eccentrically spaced from the fixed scroll member and having an end plate, a compression space formed between the fixed scroll member and the movable scroll member, the compression space being movable with its volume reduced by an orbiting movement of the movable scroll member, at least a single two-step shaped hole provided on the end plate of the fixed scroll member such that the two-step shaped hole is opened at one side thereof to the compression space, with a sectional area of the opened portion being smaller than a sectional area of the other portion, a two-step shaped piston valve slidably contacted with each step of the two-step shaped hole, a first sealed space formed between a large diameter portion and a step portion of the two-step shaped hole, a biasing means, disposed in the first sealed space and contacted with the large diameter portion of the piston valve and the step portion of the two-step shaped hole of the fixed scroll member, for biasing the piston valve in the clearance-increasing direction between an upper end surface of an involute portion of the movable scroll member and an end surface of a small diameter portion of the piston valve, a suction pressure inlet, disposed on the end plate of the fixed scroll member, for connecting the first sealed space with the suction chamber, a second sealed space formed in a confronting relation with the first sealed space with the large diameter portion of the piston valve being disposed therebetween, and a discharge pressure inlet connecting the second sealed space with a discharge port of the fixed scroll member.
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Higashiyama Akiyoshi
Iizuka Jiro
Baker & Botts L.L.P.
Brown Steven
Sanden Corporation
Thorpe Timothy S.
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