A liquid pump includes: a casing; a feed pipe bringing liquid from outside the casing to inside the casing; a pump mechanism provided in the casing and including a suction hole for sucking in the liquid and a discharge hole for discharging the liquid sucked in via the suction hole; a suction space positioned in the casing on a suction-hole inlet side and making a flow path formed by the feed pipe and the suction hole communicate with each other; and a discharge space positioned on a discharge-hole outlet side in the casing and communicating with the discharge hole. The suction space includes a gas accumulation area that is positioned above a center of an opening at casing-side end of the feed pipe, when viewed vertically and that accumulates gas brought into the casing through the feed pipe together with the liquid to separate the gas from the liquid.

A liquid pump of the present disclosure includes a container, a shaft, a bearing, a pump mechanism, a storage space, and a liquid supply passage. The shaft is disposed in the container. The bearing supports the shaft. The pump mechanism pumps a liquid by rotation of the shaft. The storage space is defined in the container at a position outside the pump mechanism. The storage space stores the liquid to be taken into the pump mechanism or the liquid to be discharged to outside of the container after being expelled from the pump mechanism. The liquid supply passage is a flow path including an inlet open to the storage space and supplying the liquid stored in the storage space to the bearing.

A gerotor pump is provided with a body defining a chamber with cylindrical wall sections and having a fluid inlet and a fluid outlet, and a cover. An internally toothed gear member is supported for rotation within the chamber about a first axis, and has a cylindrical outer wall defining a series of grooves. Each groove has an associated aperture extending through the gear member to an inner surface of the gear member, and is radially positioned between adjacent teeth of the internally toothed gear member. An externally toothed gear member is rotatably supported within the internally toothed gear member about a second axis spaced apart from the first axis, and is coupled for rotation with a drive shaft. The internally toothed gear member and externally toothed gear member cooperate to form a plurality of variable volume pumping chambers therebetween to pump fluid.

A brushless DC compressor comprising a casing, a brushless DC motor, a compression device, and a driving mechanism. The casing has a left room, a right room adjacent the left room, and a lower room. The brushless DC motor is disposed in the left room, and the compression device is disposed in the right room. The driving mechanism is disposed in the lower room, including a driving gear engaging a rotor of the brushless DC motor, a driven gear engaging a hollow shaft of the compression device and driven by the driving gear; whereby refrigerant flows into a compression space of the compression device, rotating the rotor by the stator and driving the driving gear, the driven gear, then the compression device; then being discharged from a refrigerant discharge hole and an axial groove, to form a brushless DC compressor with stronger torque and greater compression efficiency.

A stepping motor-driven system includes a stepping motor, an output device, and a belt and pulley system operably coupling the stepping motor with the output device to impart rotation therebetween. The belt and pulley system includes an input pinion engaged with the stepping motor, an output pinion engaged with the output device, and a timing belt. The timing belt is disposed about the input and output pinions, inhibits elongation, and defines a plurality of spaced-apart grooves on an inwardly-facing surface thereof that are wider than the teeth of the pinions and are configured to receive the teeth of the pinions in meshed engagement therewith. As a result, a gap is defined within each groove. The gaps permit backlash of the timing belt in response to changes in a rotational speed input to the belt and pulley system from the stepping motor, thereby inhibiting loss of control.

A fluid pump includes a pump head and a motor coupled by a drive shaft. The pump head includes a pump inlet, a pump outlet, and a pumping stage in which a movable pump element is driven by the drive shaft. The motor includes a motor rotor and a motor stator. A connector couples the motor rotor and the drive shaft. The connector includes a plate rotatable with the drive shaft, fan blades attached to the plate for establishing a flow of air for cooling the motor, and one or more counterweights attached to the plate for reducing or eliminating imbalance created by certain forces generated by the pump during operation.

A fluid pumping device is disclosed. The fluid pumping device includes a housing having a front end and a rear end, a fluid discharge opening in the front end of the housing, a pump assembly, a crank assembly rotatably connected to the pump assembly wherein the crank assembly operates the pump assembly, and a fluid storage reservoir connected to the gear housing from which fluid is drawn into the gear housing to be pumped through the fluid discharge opening.

The subject matter of this specification can be embodied in, among other things, a rotary vane actuator. A rotor assembly includes longitudinal vanes disposed radially on a central shaft, with each vane connected at their ends to a circular plates secured to the shaft. Each vane has an outer edge, wherein the shaft, a surface of each plate, and the vanes define interior pockets in the rotor assembly. A stator assembly includes two stator elements each having a first longitudinal edge and a second longitudinal edge.

An inner gear includes an insertion hole, which extends through the inner gear in an axial direction, and a first balance groove, which is axially recessed at an axial end portion of the inner gear and is communicated with the insertion hole. First and second chamfered portions are formed in an inner peripheral edge of the inner gear, which is adjacent to the insertion hole. A joint member has a leg inserted into the insertion hole. An inserting direction of the leg into the insertion hole is defined as a first direction, and a direction, which is opposite from the first direction, is defined as a second direction. In a view taken in a direction perpendicular to the axial direction, at least a part of a first direction side end portion of the leg is axially placed between a first chamfered end plane and a first groove end plane.

An example crescent seal assembly comprises: an outer crescent of a gear pump; an inner crescent of the gear pump mating with the outer crescent such that an exterior peripheral surface of the inner crescent interfaces with an interior peripheral surface of the outer crescent, forming: (i) a spring cavity, (ii) a first check valve cavity, and (iii) a second check valve cavity therebetween; a spring disposed in the at least one spring cavity; a first check pin disposed in the first check valve cavity; and a second check pin disposed in the second check valve cavity.