Abstract: An electromagnetic clutch includes a coil generating a first magnetic flux or a second magnetic flux depending on the direction of current flowing therein, a stationary core accommodating therein the coil, a stationary magnet providing a magnetic flux that opposes the first magnetic flux, a rotor rotatable concentrically with a rotatable shaft, a moving core fixed to the rotor, a moving magnet providing a magnetic flux that opposes the second magnetic flux, a sun gear fixed to the rotatable shaft, an internal gear fixed to the rotor, a planetary gear meshed with the sun gear and the internal gear, an arm supporting the planetary gear, a pulley rotatable concentrically with the rotatable shaft, a first armature being capable of coupling to the stationary core, and a second armature being capable of coupling to the moving core.

Abstract: A swash plate type compressor has a housing assembly, a drive shaft, a swash plate, a piston, a motion converter, a bleed passage, and an oil separator. The housing assembly includes a cylinder bore, a suction chamber, a discharge chamber, and a crank chamber. The drive shaft is rotatably supported by the housing assembly, and extends through the crank chamber. The bleed passage communicates between the crank chamber and the suction chamber. The oil separator is disposed in the housing assembly. The oil separator separates no or less amount of lubricating oil from the refrigerant gas in the increased rotational speed of the drive shaft than that in the decreased rotational speed of the drive shaft. The refrigerant gas passed through the oil separator is introduced into the suction chamber, and the separated lubricating oil is returned to the crank chamber.

Abstract: An object of the invention is to provide a swash plate compressor capable of realizing an excellent sliding characteristic when a drive shaft is rotated at high speed, and a high refrigerating capacity when the drive shaft is rotated at low speed. The swash plate compressor according to the invention comprises an release passage for communication between a crank chamber and a suction chamber. The release passage includes a first passage communicated to an oil rich region, in which lubricating oil is large in quantity, in the crank chamber, and a second passage communicated to an oil poor region, in which lubricating oil is small in quantity, in the crank chamber. Also, the swash plate compressor comprises an valve mechanism that increases an opening ratio of the first passage with respect to the release passage, as a rotational speed of a drive shaft increases, and increases an opening ratio of the second passage with respect to the release passage, as the rotational speed of the drive shaft decreases.

Abstract: A suction structure allows refrigerant from a suction pressure region in a piston type compressor. The suction structure includes a shifting device, a bleed passage, and a check valve. The shifting device has a valve body, a return spring, a backpressure chamber, and a backpressure passage. The valve body is movable between a connecting position and a disconnecting position. The return spring urges the valve body from the connecting position toward the disconnecting position. The backpressure chamber is defined by the valve body. The backpressure passage communicates with the suction pressure region and the backpressure chamber. The bleed passage communicates with the suction pressure region and the backpressure chamber. The check valve allows a fluid to flow from the backpressure chamber into the bleed passage.

Abstract: A suction structure is provided for allowing refrigerant into a suction pressure region in a fixed displacement piston type compressor. The compressor includes a rotary valve. The suction structure includes a shifting device which shifts between a connecting state and a disconnecting state. The shifting device includes a valve body, a return spring, a first and a second displacement chambers, and a throttle passage. The return spring urges the valve body from a connecting position toward a disconnecting position. The volume of the first displacement chamber is displacable in accordance with an amount of a fluid inside therein. The volume of the second displacement is displaced. The fluid is filled in the first and the second displacement chambers. The throttle passage connects the first displacement chamber to the second displacement chamber. The fluid flows through the throttle passage when the volume of the first displacement chamber is displaced.

Abstract: A suction structure is provided for allowing refrigerant from a suction pressure region in a piston type compressor. The compressor includes a rotary valve. The suction structure includes a shifting device which shifts between a connecting state and a disconnecting state. In the connecting state an outlet of a supply passage of the rotary valve is connected to a suction pressure region and in the disconnecting state the outlet of the supply passage is disconnected from the suction pressure region. The shifting device includes a valve body, a return spring, and a permanent magnet. The valve body is movable between a connecting position and a disconnecting position. The return spring urges the valve body from the connecting position toward the disconnecting position. The permanent magnet attracts the valve body by magnetic force from the connecting position toward the disconnecting position.

Abstract: An introduction passage of rotary valve has outlets for feeding out refrigerant in a suction pressure zone toward each of compression chambers. A switch portion in a shutoff state shuts off a portion of the suction pressure zone within a compressor from the outlets of the introduction passage. The switch portion includes a valve body, a working pressure chamber, and a working pressure applying portion. The working pressure chamber introduces a working pressure that is applied to the valve body so as to arrange the valve body at a communication position. The pressure in the suction pressure zone acts against the pressure in the working pressure chamber through the valve body.

Abstract: A fluid pump system has a cover, a fluid pump and a conduit. An inside of the cover is divided into a main chamber and a sub chamber. The fluid pump is accommodated in the main chamber. The conduit extends from the fluid pump to an outside of the cover through the sub chamber.

Abstract: A power transmission mechanism that permits power to be transmitted from an external driving source to a rotary shaft of a rotating machine includes a first rotating body, a second rotating body, an armature, and a spring clutch. The first rotating body rotates integrally with the rotary shaft of the rotating machine. The second rotating body is rotatably supported by the housing of the rotating machine and is coaxially arranged with the first rotating body. The second rotating body receives power from the external driving source. The second rotating body accommodates an electromagnetic coil and has a cylindrical extended portion. The armature is arranged to face the second rotating body. The spring clutch is wound about an outer circumference of the first rotating body. An outer circumference of the spring clutch is surrounded by the extended portion of the second rotating body. The spring clutch has a first end and a second end.

Abstract: A first rotor is rotatably supported by a housing. A second rotor rotates integrally with a rotary shaft. A power transmission mechanism is capable of transmitting power from the first rotor to the second rotor. When supplied with a current, an electromagnetic coil is capable of causing the armature plate to adhere to the first rotor. In a state where the armature plate adheres to the first rotor, the spring clutch couples the second rotor to the first rotor. An urging member is accommodated in the second rotor. The urging member is located between the rotary shaft and the armature plate. Therefore, the power transmission mechanism is compact and achieves a high performance.

Abstract: A fluid pump includes a housing, a drive source, a rotary unit and a pumping mechanism. The drive source is accommodated in the housing and includes a rotary member for rotation. The rotary unit includes the rotary member and a rotary shaft, which is operatively connected to the rotary member for rotation. The rotary unit forming an engaging portion for engaging with a maintenance tool which is prepared outside the housing. The pumping mechanism is placed in the housing and is operated in accordance with the rotation of the rotary shaft. An allowing means is formed in the housing for allowing the maintenance tool to engage with the engaging portion so as to face the engaging portion. The rotary shaft is rotated by rotating the maintenance tool in a state that the maintenance tool is engaged with the engaged portion.

Abstract: A vacuum pump having a rotary shaft that is rotated by a drive source has a main pump and a sub pump. The main pump includes a pump chamber and a gas transferring body that is located in the pump chamber. The main pump is driven by the drive source through the rotary shaft for transferring gas to an exhaust space. The sub pump is connected to the exhaust space for partially exhausting the gas from the exhaust space. The sub pump is driven by the same drive source. The displacement volume of the sub pump is smaller than that of the main pump.

Abstract: A roots pump has a housing, a plurality of rotary shafts, a rotor, a confluent passage and a closed space. The housing forms therein a pump chamber. The rotary shafts are supported on the housing in parallel relation to each other. The rotor is mounted on each of the rotary shafts, and the rotors on any adjacent rotary shafts are in engagement with each other. A set of the engaged rotors is accommodated in the pump chamber. The confluent passage is formed along one crossing line of paired imaginary swept peripheral surfaces in one-to-one correspondence with the paired and engaged rotors. The closed space is formed in one-to-one correspondence with each of the paired rotors between the paired rotors and paired peripheral wall surfaces which form the pump chamber. The closed space initially joins the confluent passage from a terminal end thereof with rotation of the paired rotors.

Abstract: A roots pump has a housing, a plurality of rotary shafts, a rotor, a confluent passage and a closed space. The housing forms therein a pump chamber. The rotary shafts are supported on the housing in parallel relation to each other. The rotor is mounted on each of the rotary shafts, and the rotors on any adjacent rotary shafts are in engagement with each other. A set of the engaged rotors is accommodated in the pump chamber. The confluent passage is formed along one crossing line of paired imaginary swept peripheral surfaces in one-to-one correspondence with the paired and engaged rotors. The closed space is formed in one-to-one correspondence with each of the paired rotors between the paired rotors and paired peripheral wall surfaces which form the pump chamber. The closed space initially joins the confluent passage from a terminal end thereof with rotation of the paired rotors.

Abstract: A reciprocating pump has an action chamber, a diaphragm, a drive shaft, and a roller. The diaphragm is displaced for changing the volume of the action chamber. A groove is formed on a circumference of the drive shaft. The roller is engaged with the groove and is connected to the diaphragm. When the drive shaft is rotated, the roller is guided by the groove to reciprocate along the axis of the drive shaft. When the roller reciprocates, the diaphragm is displaced along the axis of the drive shaft.

Abstract: A fluid pump includes a housing, a drive source, a rotary unit and a pumping mechanism. The drive source is accommodated in the housing and includes a rotary member for rotation. The rotary unit includes the rotary member and a rotary shaft, which is operatively connected to the rotary member for rotation. The rotary unit forming an engaging portion for engaging with a maintenance tool which is prepared outside the housing. The pumping mechanism is placed in the housing and is operated in accordance with the rotation of the rotary shaft. An allowing means is formed in the housing for allowing the maintenance tool to engage with the engaging portion so as to face the engaging portion. The rotary shaft is rotated by rotating the maintenance tool in a state that the maintenance tool is engaged with the engaged portion.

Abstract: A fluid pump system has a cover, a fluid pump and a conduit. An inside of the cover is divided into a main chamber and a sub chamber. The fluid pump is accommodated in the main chamber. The conduit extends from the fluid pump to an outside of the cover through the sub chamber.

Abstract: A vacuum pump has a main pump, a booster pump and a coupling member. The main pump has a first housing and a first pump mechanism accommodated in the first housing. The booster pump has a second housing and a second pump mechanism accommodated in the second housing. The booster pump and the main pump are coupled in series such that gas is sent from the booster pump to the main pump. The coupling member couples the first housing and the second housing to each other. The coupling member is directly coupled to a portion of the first housing that surrounds a last stage of the first pump mechanism such that transmission of heat to the portion is permitted.

Abstract: A vacuum pump draws gas by operating a gas conveying body in a pump chamber through rotation of a rotary shaft. The vacuum pump has an oil housing member, a stopper and a circumferential wall surface. The oil housing member defines an oil zone adjacent to the pump chamber. The stopper has a circumferential surface. The stopper is located on the rotary shaft to rotate integrally with the rotary shaft and prevents oil from entering the pump chamber. The center of curvature of the circumferential wall surface coincides with that of the rotary shaft. The circumferential wall surface surrounds at least a part of the circumferential surface of the stopper that is above the rotary shaft. The circumferential wall surface is inclined such that the distance between the circumferential wall surface and the axis of the rotary shaft decreases toward the oil zone.

Abstract: A Roots pump rotates a plurality of rotors by a pair of rotary shafts to draw gas. Each rotary shaft extends through a rear housing member of the Roots pump. An annular shaft seal is fitted around each rotary shaft and is received in a recess formed in the rear housing member. A labyrinth seal is located between an end surface of each shaft seal and the bottom of the associated recess. A resin layer is firmly attached to the end surface of each shaft seal. As a result, oil is reliably prevented from leaking into a pump chamber.