A hydraulic system includes a hydraulic gear pump with a first gear having a plurality of first gear teeth and a second gear having a plurality of second gear teeth. The hydraulic system also includes a control valve and a control circuit. The control circuit controls the pump to adjust at least one of a flow in the hydraulic system to a flow set point or a pressure in the hydraulic system to a pressure set point, and concurrently establishes an opening of the control valve to adjust at least one of the flow to the flow set point or the pressure to the pressure set point. The control circuit establishes a position of a first tooth relative to a position of a second tooth to seal a fluid path from the outlet of the hydraulic gear pump to the inlet of the hydraulic gear pump.

A refrigeration apparatus includes a compressor connected to a refrigerant circuit, and a bearing monitor. The compressor includes a compression mechanism, an electric motor, a drive shaft, and a plain bearing that supports a journal portion of the drive shaft. The bearing monitor performs an abnormal-state operation to cope with poor lubrication on the plain bearing if an abnormal state condition is satisfied. The abnormal state condition is a condition indicating that a rate of change of current exceeds a first reference value. The rate of change of current is an amount of change in a driving current usable to drive the compressor per unit time. The journal portion of the drive shaft has a surface roughness of at least 0.05 μm.

A fluid-driven actuator system includes a fluid-driven actuator and at least one proportional control valve and at least one pump connected to the fluid-driven actuator to provide fluid to operate the fluid-driven actuator. The at least one pump includes at least one fluid driver having a prime mover and a fluid displacement assembly to be driven by the prime mover such that fluid is transferred from the pump inlet to the pump outlet. The fluid-driven actuator system also includes a controller that establishes at least one of a speed and a torque of the at least one prime mover to adjust at least one of a flow in the fluid-driven system to a flow set point and a pressure in the fluid-driven actuator system to a pressure set point and concurrently establishes an opening of the at least one proportional control valve to adjust at least one of the flow to the flow set point and the pressure to the pressure set point.

A refrigeration apparatus includes a compressor connected to a refrigerant circuit, and a bearing monitor. The compressor includes a compression mechanism, an electric motor, a drive shaft, and a plain bearing that supports a journal portion of the drive shaft. The bearing monitor performs an abnormal-state operation to cope with poor lubrication on the plain bearing if an abnormal state condition is satisfied. The abnormal state condition is a condition indicating that a rate of change of current exceeds a first reference value. The rate of change of current is an amount of change in a driving current usable to drive the compressor per unit time. The journal portion of the drive shaft has a surface roughness of at least 0.05 μm.

A lubricant supplying device includes a feed pump that serves to pump lubricant from a lubricant reservoir to at least one lubrication point. A method for operating the lubricant supplying device includes measuring at least one operating parameter, such as temperature (T), of at least one part of a system to be lubricated and/or of the lubricant and/or of the environment. The at least one measured operating parameter (T) is supplied to a controller, where a required volumetric flow ({dot over (V)}.sub.target) of lubricant is determined based on a stored functional relationship ({dot over (V)}.sub.target= (T)) that generates the required volumetric flow ({dot over (V)}.sub.target) based upon the measured operating parameter (T). The feed pump is then actuated in order to achieve the determined, required volumetric flow ({dot over (V)}.sub.target).

A gerotor pump assembly, and a system and method for operating a gerotor pump assembly, result in a lubrication strategy for operating in a loss-of-prime mode. An inner drive gear may be rotated in a first direction and in a second opposite direction about an axis of rotation. The inner drive gear has a number of projections extending outwardly therefrom. An outer driven gear surrounds the inner drive gear and defines a number of recessions along an inner surface configured to engage with the projections of the inner drive gear. The outer driven gear and the inner drive gear further define at least one dynamically-changing fluid cavity therebetween. The inner drive gear and the outer driven gear define an oil transfer volume clearance between a projection and a recession in a fully engaged position. Oil is maintained within the oil transfer volume clearance as the inner drive gear is rotated.

A scroll compressor is disclosed, which may provide an oil supply path opened only in case of driving of a low pressure ratio to improve a differential pressure oil supply structure which may have a defect in oil supply in case of driving of the low pressure ratio.

A compressor is disclosed, which comprises a regulate portion provided in at least one of a main frame and a fixed scroll to control or selectively shield an opening of a delivery path or a fixed path.

One example of a gerotor pump includes an inner rotor comprising multiple teeth, the inner rotor configured to rotate about a first longitudinal gerotor pump axis. The gerotor pump also includes a hollow outer rotor including an outer surface and an inner surface having substantially identical contours, the inner surface configured to engage with the multiple teeth and to rotate about a second longitudinal gerotor pump axis. The pump includes a pump housing within which the inner rotor and the outer rotor are disposed, wherein the outer surface of the outer rotor defines gaps between the pump housing and the outer rotor.

One example of a gerotor pump includes an inner rotor comprising multiple teeth, the inner rotor configured to rotate about a first longitudinal gerotor pump axis. The gerotor pump also includes a hollow outer rotor including an outer surface and an inner surface having substantially identical contours, the inner surface configured to engage with the multiple teeth and to rotate about a second longitudinal gerotor pump axis. The pump includes a pump housing within which the inner rotor and the outer rotor are disposed, wherein the outer surface of the outer rotor defines gaps between the pump housing and the outer rotor.