A variable pressure air pump includes a first cylinder and a second cylinder movable relative to the first cylinder along a longitudinal axis. An air tube is mounted in the first and second cylinders. A mounting portion is integrally formed on a first end of the air tube. A first piston and a second piston compress air in the first and second cylinders. A connecting device is mounted to the first cylinder for coupling with an object to be inflated. An air escape device selectively seals a second chamber of the second cylinder to selectively compress the air in the second cylinder. A first check valve is mounted to the mounting portion of the air tube. A second check valve is mounted to the second piston.

A variable displacement-type compressor for a vehicle includes: an electromagnetic clutch having a first electromagnetic coil; an electromagnetic control valve having an second electromagnetic coil; a first connector having an input terminal portion and an output terminal portion, the first connector being integrated with and electrically connected to one of the electromagnetic clutch and the electromagnetic control valve, and disposed at a position away from the other one of the electromagnetic clutch and the electromagnetic control valve, the input terminal portion being connectable to a vehicle-side connector, and the output terminal portion being electrically connectable to the other one; and a second connector provided separately from the other one, connected to the other one through a cable, and connected to the output terminal portion of the first connector.

A method for operating a pressure control system having a multi-stage compressor includes providing a multiply compressed pressure medium by the multi-stage compressor for filling a pressure medium reservoir or pressure medium chambers of the pressure control system. Providing the multiply compressed pressure medium includes (i) providing, by a first compression stage, a pre-compressed pressure medium and additionally compressing, at least by a second compression stage, the pre-compressed pressure medium, and/or (ii) introducing an already-compressed charging pressure medium into an intermediate volume between the first compression stage and the second compression stage of the multi-stage compressor and further compressing the charging pressure medium at least by the second compression stage. The charging pressure medium simultaneously passes via a control line to a control input of a shut-off valve that interacts with the first compression stage, such that a charging pressure of the charging pressure medium predefines a control pressure.

A spool operation failure due to foreign matter contamination is prevented. A variable displacement compressor 100 includes a first control valve 300 controlling the opening degree of a supply passage 145, a check valve 350, a second control valve 400 controlling the opening degree of a discharge passage 146, and a back-pressure relief passage 147. The second control valve 400 includes a back pressure chamber 410 communicating with an intermediate supply passage 145b1, a valve chamber 420 to which a valve hole 103d and a discharge hole 431a are open and that constitutes a part of the discharge passage 146, a partition member 430 partitioning into the back pressure chamber 410 and the valve chamber 420, and a spool 440 extending through a through hole 432a formed in the partition member 430. The spool 440 has a pressure receiving portion 441 disposed in the back pressure chamber 410, a valve portion 442 disposed in the valve chamber 420, and a shaft portion 443. The spool 440 is supported in a manner slidable in the opening and closing directions on the partition member 430 by arranging the spool valve 440a, constituted by the valve portion 442 and the shaft portion 443, to be in contact with the partition member 430.

A variable pressure air pump includes a first cylinder and a second cylinder movable relative to the first cylinder along a longitudinal axis. An air tube is mounted in the first and second cylinders. A mounting portion is integrally formed on a first end of the air tube. A first piston and a second piston compress air in the first and second cylinders. A connecting device is mounted to the first cylinder for coupling with an object to be inflated. An air escape device selectively seals a second chamber of the second cylinder to selectively compress the air in the second cylinder. A first check valve is mounted to the mounting portion of the air tube. A second check valve is mounted to the second piston.

A variable pressure air pump includes a first cylinder and a second cylinder movable relative to the first cylinder along a longitudinal axis. An air tube is mounted in the first and second cylinders. A mounting portion is integrally formed on a first end of the air tube. A first piston and a second piston compress air in the first and second cylinders. A connecting device is mounted to the first cylinder for coupling with an object to be inflated. An air escape device selectively seals a second chamber of the second cylinder to selectively compress the air in the second cylinder. A first check valve is mounted to the mounting portion of the air tube. A second check valve is mounted to the second piston.

Provided is a variable-capacity compressor control valve with a simple configuration that can secure the size of a sub valve element portion of a sub valve element, which is adapted to open or close an in-valve release passage, and can improve the actuation property and reduce the size of the control valve. The sub valve element (17) is integrated with the plunger (37) for moving the main valve element (15) in the direction to open or close a valve orifice so that the sub valve element (17) always moves together with the plunger (37). The sub valve element (17) is securely inserted in the plunger (37).

A hybrid or battery type working machine including a hydraulic pump, an electric motor, an electric storage device, and a control device which controls a pump absorption horsepower maximum value in accordance with an amount of electricity stored in the electric storage device. The control device reduces the pump absorption horsepower maximum value by dividing the pump absorption horsepower maximum value into a plurality of regions having different target flow rates, and reduces the pump absorption horsepower maximum value from an old pump absorption horsepower maximum value corresponding to the pump absorption horsepower maximum value which has not yet been reduced to a new pump absorption horsepower maximum value corresponding to the pump absorption horsepower maximum value which has been reduced, so that temporal differences among the regions can increase in a descending order of a target flow rate.

A hybrid or battery type working machine including a hydraulic pump, an electric motor, an electric storage device, and a control device which controls a pump absorption horsepower maximum value in accordance with an amount of electricity stored in the electric storage device. The control device reduces the pump absorption horsepower maximum value by dividing the pump absorption horsepower maximum value into a plurality of regions having different target flow rates, and reduces the pump absorption horsepower maximum value from an old pump absorption horsepower maximum value corresponding to the pump absorption horsepower maximum value which has not yet been reduced to a new pump absorption horsepower maximum value corresponding to the pump absorption horsepower maximum value which has been reduced, so that temporal differences among the regions can increase in a descending order of a target flow rate.

A pressure-acting chamber is defined by a first cylinder block and a spacer. The pressure-acting chamber communicates with a discharge chamber via a supply passage. A load based on the pressure difference between the pressure-acting chamber and a swash plate chamber is applied to a rotary shaft and acts toward a second thrust bearing.