Patent ID: 8366407
Filing Date: 2013-02-05
Classification: F04B

Abstract:
1. A device for reducing pulsation in a variable displacement compressor, wherein the compressor is connected to an external refrigerant circuit, the compressor comprising: a compressor housing having a crank chamber, a suction chamber, a discharge chamber and a plurality of cylinder bores; a plurality of pistons slidably received in the respective cylinder bores; and a reciprocating mechanism provided in the crank chamber for reciprocating the pistons in the cylinder bores, wherein as the pistons are reciprocated, refrigerant gas in the suction chamber is drawn into the cylinder bores for compression and the compressed refrigerant gas is discharged into the discharge chamber, wherein pressure in the crank chamber is controlled to vary a discharge amount of the refrigerant gas; the device for reducing pulsation comprising: a suction passage formed in the compressor housing, wherein the suction chamber communicates with the external refrigerant circuit through the suction passage; a control valve disposed in the suction passage for controlling opening of the suction passage, the control valve comprising: a valve housing disposed in the compressor housing; a spool valve slidably disposed in the valve housing, wherein the spool valve has formed therethrough a flow hole, wherein pressure in the suction passage acts on the spool valve to move the spool valve; a damper chamber provided in the valve housing, wherein the damper chamber communicates with the suction passage adjacent to the external refrigerant circuit through the flow hole, a back pressure valve slidably disposed in the valve housing, wherein the back pressure valve is located in a facing relation to the spool valve so that the damper chamber is formed between the back pressure valve and the spool valve, wherein the pressure in the crank chamber acts on the back pressure valve to move the back pressure valve; a compression spring disposed in the damper chamber for urging the spool valve and the back pressure valve away from each other; and a releasing hole formed through the valve housing for releasing the refrigerant gas from the damper chamber, wherein a communication passage is formed in the compressor housing, wherein the releasing hole communicates with the suction chamber through the communication passage, wherein an opening between the releasing hole and the damper chamber is variable so as to be fully closed and fully opened by the movement of the back pressure valve, wherein effective cross-sectional area and effective length of the flow hole are determined based on frequency of a specific pulsation of the refrigerant gas and volume of the damper chamber at the time of the development of the specific pulsation in such a manner that when the specific pulsation is developed, resonance effect of a Helmholtz resonator takes place in the damper chamber, wherein the effective cross-sectional area and the effective length of the flow hole are determined based on frequency of the specific pulsation of the refrigerant gas and the total volume of the damper chamber at the time of the development of the specific pulsation, the suction chamber, the releasing hole and the communication passage.