Scroll fluid machine that maintains control accuracy of back pressure
The scroll-type compressor comprises a fixed scroll and an orbiting scroll engaged with each other; a back pressure control valve 50 inserted from the large-diameter side of the stepped-shaped pressure release passage L 4 which communicates between a suction chamber H 1 and a back pressure chamber H 3 which applies a back pressure for pressing the orbiting scroll against the fixed scroll. The scroll-type compressor further comprises an O-ring 60 fitted in a circumferential groove 53 a formed in the outer peripheral surface of the valve 50 , and a ring member 61 press-fitted into the large-diameter side of the pressure release passage L 4 , and holds the valve 50 between the ring member 61 and the stepped portion. Then, the compressive stress is unlikely to be applied to the valve 50 , and the deformation of the valve 50 is reduced to prevent the reduction in the control accuracy of the back pressure.
1. A scroll fluid machine comprising:
a fixed scroll and an orbiting scroll engaged with each other;
a back pressure control valve inserted into a communication passage communicating between a back pressure chamber which applies a back pressure that presses the orbiting scroll against the fixed scroll and an outside of the back pressure chamber for controlling a pressure in the back pressure chamber;
a seal member fitted into a circumferential groove formed in an outer peripheral surface of the back pressure control valve;
a ring member press-fitted into the communication passage to fix the back pressure control valve;
wherein the ring member is constituted by a member that is different from the back pressure control valve, and has a portion protruding from the communication passage;
the protruding portion forms a locking part with which a tool can be locked, the communication passage is a stepped shape;
the back pressure control valve is inserted from a large-diameter side of the communication passage; and
the ring member is press-fitted into the large-diameter side of the communication passage, and holds and fixes the back pressure control valve between the ring member and a stepped portion of the communication passage.
2. The scroll fluid machine according to claim 1 , wherein the fixed and orbiting scrolls compress or expand a CO 2 refrigerant.
3. The scroll fluid machine according to claim 2 , wherein the back pressure control valve is a unit-type differential-pressure-operation-type check valve which integrates at least a valve body, an elastic body for biasing the valve body in the valve closing direction, and a casing for accommodating the valve body and elastic body.
4. The scroll fluid machine according to claim 1 , wherein the locking part is a circumferential groove formed in an outer peripheral surface or an inner peripheral surface of the protruding portion.
5. The scroll fluid machine according to claim 4 , wherein the back pressure control valve is a unit-type differential-pressure-operation-type check valve which integrates at least a valve body, an elastic body for biasing the valve body in the valve closing direction, and a casing for accommodating the valve body and elastic body.
6. The scroll fluid machine according to claim 1 , wherein the locking part is a plurality of projections formed on an outer peripheral surface or an inner peripheral surface of the protruding portion.
7. The scroll fluid machine according to claim 6 , wherein the back pressure control valve is a unit-type differential-pressure-operation-type check valve which integrates at least a valve body, an elastic body for biasing the valve body in the valve closing direction, and a casing for accommodating the valve body and elastic body.
8. The scroll fluid machine according to claim 1 , wherein the locking part is a plurality of recessed portions formed in an outer peripheral surface or an inner peripheral surface of the protruding portion.
9. The scroll fluid machine according to claim 8 , wherein the back pressure control valve is a unit-type differential-pressure-operation-type check valve which integrates at least a valve body, an elastic body for biasing the valve body in the valve closing direction, and a casing for accommodating the valve body and elastic body.
10. The scroll fluid machine according to claim 1 , wherein the back pressure control valve is a unit-type differential-pressure-operation-type check valve which integrates at least a valve body, an elastic body for biasing the valve body in the valve closing direction, and a casing for accommodating the valve body and elastic body.
11. The scroll fluid machine according to claim 10 , wherein the outside of the back pressure chamber is a fluid suction chamber.
12. The scroll fluid machine according to claim 1 , wherein the outside of the back pressure chamber is a fluid suction chamber.