A vehicle-mounted electric oil-free air compressor, including a motor, a box body, a piston, and a flywheel shaft. The motor is fixed on the box body, a cylinder cover is at the top of the box body, a main shaft of the motor includes a coupling driving end, the flywheel shaft is driven by an elastic body to rotate. The piston includes a primary intake valve piece and a primary exhaust valve piece, the box body is provided with a secondary cavity, a secondary exhaust valve piece is provided at a vent hole on one side of the cavity, and the primary exhaust valve piece is also a secondary intake valve piece of the compressor, increasing the exhaust pressure. When the piston reciprocates, the stress is balanced and the vibration is small, and with the assistance of a high-efficiency flywheel, the operation of the air compressor is stable.

Disclosed herein is a compressor that includes a casing, a fastening part disposed at a portion corresponding to a support bracket provided in a compressor mounting part of a vehicle on the casing, and a fastener connecting the support bracket to the fastening part, wherein a compressor's center of gravity and a compressor's point of support supported by the fastener are positioned in a longitudinal direction of the fastener. The present disclosure has an effect of relieving rotational moment and fatigue stress occurring in the compressor when the compressor is mounted to the vehicle.

A compressor arrangement for operating a compressed air supply installation includes a pneumatic compressor and an electric motor arranged inside a drive housing, the electric motor having an internal stator and an external outer rotor. The external outer rotor is arranged in a rotatable manner about the internal stator. The external outer rotor is supported in a rotatable manner about a center axis with respect to the drive housing via a bearing arrangement. The bearing arrangement has at least one bearing. The external outer rotor is supported by the bearing arrangement on an outer circumference of the outer rotor.

A compressor having curved connecting rods, comprising cylinders (8), pistons (9), piston pins (10), curved connecting rods (11), a swing rod (12), a crank pin (13), a crankshaft (14) and the other components; when the compressor having curved connecting rods works, a power machine driving the crankshaft (14) to rotate, the rotation of the crankshaft (14) driving the crank pin (13) to push the swing rod (12) to swing left and right, and the movement, towards the left and right, of the swing rod (12) driving the curved connecting rods (11) and the pistons (9) to reciprocate within the cylinders (8) and perform work in a compression manner.

A reciprocating compressor-expander according to the present invention comprises a cylinder, a piston, a crankshaft connected to the piston, a first valve for a low pressure compressible fluid, a second valve for a high pressure compressible fluid, and a valve drive mechanism for driving the first valve and the second respectively such that, during a compression process, the low-pressure compressible fluid is sucked into the cylinder from the first valve in synchronization with the rotation of the crankshaft and the high-pressure compressible fluid compressed in the cylinder is discharged from the second valve, and that, during an expansion process, the high-pressure compressive fluid is introduced from the second valve into the cylinder, and the low-pressure compressible fluid expanded in the cylinder is discharged from the first valve.

A positioning structure of a motor of an air compressor contains: a base, a cylinder, the motor, and a transmission mechanism. The base includes a first locating orifice and a second locating orifice. The cylinder includes an air storage seat. A small-diameter gear is fitted on the motor via the first locating orifice. A bearing housing of the motor is accommodated in the first locating orifice. The transmission mechanism actuates a piston to move in the cylinder reciprocately. The base includes two symmetrical elongated plates having two hooks respectively and includes two symmetrical arcuate retainers. An outer wall of the motor is retained by the two symmetrical arcuate retainers, and the two hooks are engaged with the magnetic coil.

An air compressor contains: a torque gear on which a central orifice and a connection rod are arranged. The central orifice has screw threads defined thereon and corresponds to one of multiple positioning orifices of a base, the one positioning orifice is configured to accommodate a bearing, and a screw bolt is inserted through the bearing in the base so as to screw with the central orifice via the torque gear. The connection rod of the torque gear is rotatably connected with a piston so that the piston moves in a cylinder to produce compressed air, the torque gear matingly contacts with the bearing along the screw bolt, and the bearing is not broken in the one positioning orifice, thus moving the piston in the cylinder reciprocately.

A two-stage high-pressure pump includes a reduction gearbox disposed in front of a motor, a-crank shaft connected to an output shaft of the reduction gearbox, a connecting rod having one side connected to the crank shaft and the other side connected to a primary piston, a primary one-way valve disposed at one end of the primary piston, and a gas storage chamber provided at the middle of the primary piston. The other end of the primary piston is connected to a secondary piston rod in a highly sealed manner. The secondary piston rod is provided with a vent in the middle, and the other end of the secondary piston is connected to a high-pressure piston. A secondary one-way valve is disposed in the secondary high-pressure piston. A noise attenuating filter and a one-way valve block are disposed at an air inlet of the primary cylinder cover.

A hermetic refrigerant compressor (100) includes a sealed container (101) in which lubricating oil (103) having a kinematic viscosity in a range of 1 to 9 mm.sup.2/S at 40° C. is stored, the lubricating oil (103) containing a sliding modifier that is either sulfur or a sulfur-containing compound. A compression element (107) includes a shaft part that is a crank shaft (108). In a case where a sliding surface of a main shaft (109) is a single sliding surface, a length of the single sliding surface in an axial direction is a single sliding length L, whereas in a case where the sliding surface is divided into a plurality of sliding surfaces, a length of one of the sliding surfaces in the axial direction, the one sliding surface having the least length in the axial direction among the plurality of sliding surfaces, is the single sliding length L, and a ratio L/D of the single sliding length L to an external diameter D of the main shaft (109) is less than or equal to 0.51.

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.