A rotary piston engine and a method for manufacturing a sealing in a rotary piston engine are described. The rotary piston engine has at least two piston pairs respectively connected via a link, the pistons of which are arranged at opposite ends of the links and, during operation, circulate on an at least approximately circular path in a piston housing, such that varying working volumes are enclosed between the pistons of different piston pairs during the circulation and that, via a sealing provided between the piston housing and the pistons, a fluid flow between the enclosed working volumes is at least impeded. The technical solution described is characterized in that the sealing is formed by a gap between the pistons and the piston housing and surfaces of the pistons and the piston housing delimiting the gap at least at times are irregularly structured.

A rotary piston engine and a method for manufacturing a sealing in a rotary piston engine are described. The rotary piston engine has at least two piston pairs respectively connected via a link, the pistons of which are arranged at opposite ends of the links and, during operation, circulate on an at least approximately circular path in a piston housing, such that varying working volumes are enclosed between the pistons of different piston pairs during the circulation and that, via a sealing provided between the piston housing and the pistons, a fluid flow between the enclosed working volumes is at least impeded. The technical solution described is characterized in that the sealing is formed by a gap between the pistons and the piston housing and surfaces of the pistons and the piston housing delimiting the gap at least at times are irregularly structured.

Variable volume chamber devices are disclosed. The chambers may be defined by the space between two complementary rotors. The volume of the chambers may vary as a function of the variation of relative rotational speeds of the two rotors.

Variable volume chamber devices are disclosed. The chambers may be defined by the space between two complementary rotors. The volume of the chambers may vary as a function of the variation of relative rotational speeds of the two rotors.

A gerotor pump having an inner rotor and an outer rotor, which is also the rotor of an electric drive, having a housing and a flange which closes the housing with the motor compartment, the rotor being arranged on a shaft and sealing against the flange at a gap, wherein, in addition to the gap, there is at least one device with which at least a partial pressure compensation takes place between the suction region of the gerotor pump and the motor compartment of the gerotor pump.

Variable volume chamber devices are disclosed. The chambers may be defined by the space between two complementary rotors. The volume of the chambers may vary as a function of the variation of relative rotational speeds of the two rotors.

A multiple vane kinetic system produces variation in an enclosed volume between pairs of radial vane sets independent of each other and coaxial with a central axis within a annular casing that encapsulates the vane sets. The system operates in a sequence where the vane sets function as rotating links of the mechanism for a particular period, which is preceded and succeeded by another period where either vane sets successively alternate between being a fixed link and a rotating link of the mechanism and during the former period the volumes between vanes remain constant as long as the vane sets have equal angular velocities, otherwise varies at rates proportional to differing angular velocities. The two time periods are controlled by timing devices actuating vane sets to be coupled and decoupled with a power shaft and the variation in length of two time periods makes roto-dynamic variable displacement machine.

An oil pump is provided. The oil pump comprises: a shell; a rotor mounting part on the shell and having a rotor supporting structure; and a rotor mechanism disposed on the rotor mounting part. The shell has an inlet and an outlet and defines a low-pressure oil chamber and a high-pressure oil chamber. A partition wall is disposed between the low-pressure oil chamber and the high-pressure oil chamber for separating the low-pressure oil chamber and the high-pressure oil chamber. An engine cover comprising the oil pump and an engine comprising the engine cover are also provided.

Provided is a hollow rotor and method for making a hollow rotor for a gerotor system, the gerotor system including inner and outer rotors having interengaging lobed profiles. At least one of the inner or outer rotors comprises the hollow rotor, the hollow rotor including radially inner and outer walls radially spaced-apart in relation to a rotational axis of the rotor and walls extending between the radially inner and outer walls for closing axial ends of the hollow rotor. The radially inner and outer walls define therebetween a cavity, thus providing for a hollow or empty interior of the hollow rotor. At least one of the radially inner or outer walls forms a plurality of lobes circumferentially spaced-apart around the cavity.