The invention relates to an eccentric screw pump comprising at least one stator (1) made from an elastic material and a rotor (2) that is rotatable in the stator (1), wherein at least some regions of the stator (1) are surrounded by a stator casing (3), and the stator casing (3), as a casing split along its length, consists of at least two casing segments (19) and forms a stator clamping device by means of which the stator can be clamped against the rotor (2) in the radial direction, wherein the stator clamping device has one or more movable adjusting elements which work on the casing segments (19) to adjust and clamp the stator. Said pump is characterised in that the stator clamping device comprises one or more actuators which are connected to the adjusting elements or are equipped with adjusting elements for an automated advancement of the stator.

A rotary positive displacement pump for fluids, in particular for the lubrication oil of a motor vehicle engine (60), has a displacement that can be regulated by means of the rotation of a stator ring (12) having an eccentric cavity (13) in which the rotor (15) of the pump (1) rotates. The stator ring (12) is configured as a multistage rotary piston for displacement regulation and is arranged to be directly driven by a fluid under pressure, in particular oil taken from a delivery side (19) of the pump or from a point of the lubrication circuit located downstream the oil filter (62). The invention also concerns a method of regulating the displacement of the pump (1) and a lubrication system for a motor vehicle engine in which the pump (1) is used.

A scroll compressor according to the present invention includes a casing, an orbiting member provided within the casing and performing an orbiting motion, a non-orbiting member forming a compression chamber together with the orbiting member, the compression chamber having a suction chamber, an intermediate pressure chamber and a discharge chamber, a communication passage configured to bypass a refrigerant of the compression chamber into the casing, an opening/closing valve assembly configured to open and close the communication passage, and a switching valve assembly configured to operate the opening/closing valve assembly, the switching valve assembly being provided outside the casing and connected to the opening/closing valve assembly, whereby an installation of the bypass hole can result in prevention of over-compression and an installation of a control valve for varying a capacity outside the casing can result in reduction of costs for the control valve.

A scroll compressor according to the present invention includes a casing, an orbiting member provided within the casing and performing an orbiting motion, a non-orbiting member forming a compression chamber together with the orbiting member, the compression chamber having a suction chamber, an intermediate pressure chamber and a discharge chamber, a communication passage configured to bypass a refrigerant of the compression chamber into the casing, an opening/closing valve assembly configured to open and close the communication passage, and a switching valve assembly configured to operate the opening/closing valve assembly, the switching valve assembly being provided outside the casing and connected to the opening/closing valve assembly, whereby an installation of the bypass hole can result in prevention of over-compression and an installation of a control valve for varying a capacity outside the casing can result in reduction of costs for the control valve.

A variable capacity compressor is provided, including: two cylinders and a middle plate; at least one flow channel provided in the middle plate, wherein one end of the flow channel is connected to an exhaust chamber of any one of the two cylinders, the other end is connected to a suction chamber of the other one of the two cylinders. In present disclosure, by setting a flow channel in the middle plate of the variable capacity compressor, the exhaust chamber of one cylinder is connected to the suction chamber of the other cylinder. When the flow channel is completely closed, the two cylinders operate independently; when the flow channel is opened, the refrigerant in the exhaust chamber flows into the suction chamber through the flow channel, that is, the upper cylinders and the lower cylinder are connected to each other, which can adjust the capacity of the compressor.

A variable capacity compressor is provided, including: two cylinders and a middle plate; at least one flow channel provided in the middle plate, wherein one end of the flow channel is connected to an exhaust chamber of any one of the two cylinders, the other end is connected to a suction chamber of the other one of the two cylinders. In present disclosure, by setting a flow channel in the middle plate of the variable capacity compressor, the exhaust chamber of one cylinder is connected to the suction chamber of the other cylinder. When the flow channel is completely closed, the two cylinders operate independently; when the flow channel is opened, the refrigerant in the exhaust chamber flows into the suction chamber through the flow channel, that is, the upper cylinders and the lower cylinder are connected to each other, which can adjust the capacity of the compressor.

A scroll compressor according to the present invention includes a casing, an orbiting member provided within the casing and performing an orbiting motion, a non-orbiting member forming a compression chamber together with the orbiting member, the compression chamber having a suction chamber, an intermediate pressure chamber and a discharge chamber, a communication passage communicating inside and outside of the compression chamber with each other, an opening/closing valve assembly provided outside the non-orbiting member within the casing and opening and closing the communication passage, and a switching valve assembly provided within the casing and operating the opening/closing valve assembly, whereby a facilitated fabrication, improved valve responsiveness and a relaxed restriction for a specification of a valve can be achieved, and also an over-compression can be prevented by an installation of a check valve, and an assembling efficiency can be improved by installing two valve assemblies outside the non-orbiting member.

A scroll compressor according to the present invention includes a casing, an orbiting member provided within the casing and performing an orbiting motion, a non-orbiting member forming a compression chamber together with the orbiting member, the compression chamber having a suction chamber, an intermediate pressure chamber and a discharge chamber, a communication passage communicating inside and outside of the compression chamber with each other, an opening/closing valve assembly provided outside the non-orbiting member within the casing and opening and closing the communication passage, and a switching valve assembly provided within the casing and operating the opening/closing valve assembly, whereby a facilitated fabrication, improved valve responsiveness and a relaxed restriction for a specification of a valve can be achieved, and also an over-compression can be prevented by an installation of a check valve, and an assembling efficiency can be improved by installing two valve assemblies outside the non-orbiting member.

A scroll compressor may include a block insertion groove recessed by a predetermined depth into a rear surface of a non-orbiting scroll to accommodate a discharge port and at least one bypass hole, and a retainer block having at least one bypass valve to open and close the at least one bypass hole may be fixedly inserted into the block insertion groove. Accordingly, the at least one bypass valve that suppresses or prevents overcompression in a compression chamber is not fastened to a non-orbiting end plate, which may allow the non-orbiting end plate to be formed thin. As the non-orbiting end plate is reduced in thickness, a length of the at least one bypass hole may be reduced, thereby decreasing a dead volume in the at least one bypass hole.

Variable volume ratio compressors may be controlled using a switching parameter based on compressor speed and suction density to improve the matching of compressor volume ratio to desired discharge conditions. Delay periods may be implemented in the determination of when to change volume ratio to control the frequency of changes to the volume ratio. The switching parameter may be a product of the compressor speed and suction density. The volume ratio of the compressor may be controlled by switching valves directing pressure to a piston of a variable volume ratio system of the compressor.