Compressor having capacity modulation
A compressor may include a shell assembly, a first scroll, a second scroll, a piston, and a piston-retention member. The piston engages the first scroll and may be partially received within a recess defined by the shell assembly. The piston and the shell assembly may cooperate to define a pressure chamber. The pressure chamber may be in selective fluid communication with a source of working fluid to control movement of the piston relative to the shell assembly. The piston-retention member may be mounted to the piston and selectively engage a rotationally fixed structure. The piston-retention member allows rotation of the piston relative to the first scroll in a first rotational direction and restricts rotation of the piston relative to the first scroll in a second rotational direction.
1. A compressor comprising:
a shell assembly defining a discharge chamber;
a first scroll disposed within the shell assembly and including a first end plate and a first spiral wrap extending from the first end plate;
a second scroll disposed within the shell assembly and including a second end plate and a second spiral wrap extending from the second end plate, the first and second spiral wraps meshing;
a piston engaging the first scroll and cooperating with the shell assembly to define a pressure chamber therebetween, wherein the pressure chamber is in selective fluid communication with a first source of working fluid to control movement of the piston relative to the shell assembly; and
a piston-retention member mounted to the piston and selectively engaging a rotationally fixed structure, wherein the piston-retention member allows rotation of the piston relative to the first scroll in a first rotational direction, and wherein the piston-retention member selectively engages a selected one of a plurality of notches formed on the rotationally fixed structure to restrict rotation of the piston relative to the first scroll in a second rotational direction that is opposite the first rotational direction.
2. The compressor of claim 1 , wherein a spring engages the piston-retention member and the piston, and wherein the spring rotationally biases the piston-retention member into engagement with the selected one of the plurality of notches formed in the rotationally fixed structure.
3. The compressor of claim 1 , wherein the rotationally fixed structure is a partition of the shell assembly, wherein the partition partially defines the discharge chamber and a suction chamber.
4. The compressor of claim 3 , wherein the plurality of notches are formed on a wear ring of the partition.
5. The compressor of claim 3 , wherein the piston-retention member is pivotably mounted to the piston.
6. The compressor of claim 5 , wherein a spring engages the piston-retention member and the piston, and wherein the spring biases the piston-retention member into engagement with the selected one of the plurality of notches.
7. The compressor of claim 6 , wherein the plurality of notches are arranged on the partition in a circular pattern that extends around a portion of the piston.
8. The compressor of claim 1 , wherein the piston threadably engages the first scroll.
9. The compressor of claim 8 , wherein a passage in the piston provides fluid communication between a discharge passage in the first scroll and the discharge chamber.
10. The compressor of claim 1 , wherein the first scroll is a non-orbiting scroll and the second scroll is an orbiting scroll.
11. The compressor of claim 1 , wherein the piston-retention member is movable relative to the piston and the rotationally fixed structure to allow rotation of the piston relative to the first scroll in the first rotational direction.
12. A compressor comprising:
a shell assembly having an end cap at least partially defining a discharge chamber and a pressure chamber;
a first scroll disposed within the shell assembly and including a first end plate and a first spiral wrap extending from the first end plate;
an second scroll disposed within the shell assembly and including a second end plate and a second spiral wrap extending from the second end plate, the first and second spiral wraps meshing with each other;
a piston including a main body and a flange portion extending radially outward from the main body, wherein the main body threadably engages the first scroll, wherein the flange portion is received within a recess defined by the end cap such that the piston cooperates with the end cap to define the pressure chamber, wherein the pressure chamber is in selective fluid communication with a source of working fluid to control movement of the piston relative to the shell assembly; and
a piston-retention member pivotably mounted to the piston and selectively engaging a rotationally fixed structure, wherein the piston-retention member allows threadable rotation of the piston relative to the first scroll in a first rotational direction to threadably tighten the piston to the first scroll, and wherein the piston-retention member selectively engages a selected one of a plurality of notches formed on the rotationally fixed structure to restrict rotation of the piston relative to the first scroll in a second rotational direction to restrict the piston from threadably loosening from the first scroll.
13. The compressor of claim 12 , wherein the piston-retention member is a lever that is rotatable about a rotational axis that is spaced apart from a rotational axis about which the piston is rotatable relative to the rotationally fixed structure.
14. The compressor of claim 12 , wherein a spring engages the piston-retention member and the piston, and wherein the spring biases the piston-retention member into engagement with the selected one of the plurality of notches formed in the rotationally fixed structure.
15. The compressor of claim 12 , wherein the rotationally fixed structure is a partition of the shell assembly, wherein the partition partially defines the discharge chamber and a suction chamber.
16. The compressor of claim 15 , wherein the plurality of notches are formed on a wear ring of the partition.
17. The compressor of claim 15 , wherein a spring engages the piston-retention member and the piston, and wherein the spring biases the piston-retention member into engagement with the selected one of the plurality of notches.
18. The compressor of claim 15 , wherein the plurality of notches are arranged on the partition in a circular pattern that extends around the main body of the piston.
19. The compressor of claim 12 , further comprising:
a discharge valve disposed axially between an axial end of the piston and a surface of the first end plate,
wherein a passage in the piston provides fluid communication between a discharge passage in the first scroll and the discharge chamber, and
wherein another passage in the piston provides fluid communication between the pressure chamber and the discharge chamber.
20. The compressor of claim 12 , wherein the piston-retention member is movable relative to the piston and the rotationally fixed structure to allow rotation of the piston relative to the first scroll in the first rotational direction.
21. The compressor of claim 1 , wherein the piston-retention member is a lever that is rotatable about a rotational axis that is spaced apart from a rotational axis about which the piston is rotatable relative to the rotationally fixed structure.