Variable displacement compressor and its assembling method

A compressor including a cylinder block having a cylinder bore, a first housing attached to a first end of the cylinder block to define a crank chamber, a second housing attached to a second end of the cylinder block via a valve plate to define a suction chamber and a discharge chamber, a drive plate located in the crank chamber and mounted on a drive shaft, and a piston operably coupled to the drive plate and located in the cylinder bore, wherein said drive plate converts rotation of the drive shaft to reciprocating movement of the piston in the cylinder bore, said piston compressing gas supplied to the cylinder bore from a separate external circuit by way of a suction chamber and discharging the compressed gas to the external circuit by way of a discharge chamber, wherein the drive plate is tiltable between a maximum inclination position and a minimum inclination position according to a difference between the pressure in the crank chamber and the pressure in the cylinder bore, said piston moving by a stroke based on the inclination of the drive plate to control the displacement of the compressor, said compressor comprising:

• said cylinder block having a shutter chamber extending along an axis of the drive shaft and opening to said first end and said second end;
• a shutter member accommodated in the shutter chamber and movable along the axis of the drive shaft, wherein said shutter member is movable between a first position and a second position in response to the inclination of the drive plate, said shutter member connecting the external circuit with the suction chamber in the first position and disconnecting the external circuit from the suction chamber in the second position;
• said valve plate having a positioning surface facing the shutter member;
• said shutter member having an end surface that abuts against the positioning surface when the shutter member is positioned in the second position, wherein said drive plate is held at the minimum inclination position when the end surface abuts against the positioning surface;
• said shutter chamber having a diameter that is constant in an axial direction with respect to the shutter chamber, whereby said shutter member is removably inserted into the shutter chamber from the second end of the cylinder block;
• a spring located in the shutter chamber to bias the shutter member toward the drive plate;
• and
• an adjuster located between the drive plate and the spring to adjust the minimum inclination position of the drive plate.

A method for assembling a variable displacement compressor, wherein said compressor includes a cylinder block having a cylinder bore, a first housing attached to a first end of the cylinder block, a second housing attached to a second end of the cylinder block, a crank chamber defined between the cylinder block and the first housing, a drive plate located in the crank chamber and mounted on a drive shaft, and a piston operably coupled to the drive plate and located in the cylinder bore, wherein said drive plate converts rotation of the drive shaft to reciprocating movement of the piston in the cylinder bore, said piston compressing gas supplied to the cylinder bore from a separate external circuit by way of a suction chamber and discharging the compressed gas to the external circuit by way of a discharge chamber, wherein the drive plate is tiltable between a maximum inclination position and a minimum inclination position according to a difference between the pressure in the crank chamber and the pressure in the cylinder bore, said piston moving by a stroke based on the inclination of the drive plate to control the displacement of the compressor, wherein said compressor further includes a shutter chamber extending through the cylinder bore from said first end to said second end, a shutter member accommodated in the shutter chamber and movable along the axis of the drive shaft, a thrust bearing supported on the drive shaft between the drive plate and the shutter member, and a spring for biasing the shutter member toward the drive plate, wherein said shutter member is movable between a first position and a second position in response to the inclination of the drive plate, said shutter member connecting the external circuit with the suction chamber in the first position and disconnecting the external circuit from the suction chamber in the second position, wherein said drive plate is held at the minimum inclination position when the shutter member is positioned in the second position, said method comprising the steps of:

• attaching the first housing, the drive shaft, the drive plate and the piston to the cylinder block from said first end;
• inserting the thrust bearing, the shutter member and the spring into the shutter chamber from said second end before the second housing is attached to the second end;
• and
• attaching a receiving member to the cylinder block from the second end to receive the spring.