A toothing for a gerotor pump comprises a plurality of outer teeth (10) at a gerotor inner element (1) and a plurality of inner teeth (20) greater by one at a gerotor outer element (2), wherein a centre (M1) of the gerotor inner element (1) is offset from a centre (M2) of the gerotor outer element (2) by an eccentricity (e), the outer teeth (10) thereby meshing with the inner teeth (20). A contour of the outer teeth (10) at the gerotor inner element (1) is essentially defined by a curve of a single ellipse from a tooth tip (11) continuously via tooth flanks (13) to a transition radius (14) towards a tooth space or a tooth root (12); wherein the principal axis of the ellipse is arranged radially to the gerotor inner element (1) and the centre of the ellipse determines a radius (R.sub.min) at the gerotor inner element (1) which corresponds to the maximum meshing depth of the gerotor outer element (2) between the outer teeth (10) at the meshing.

A positive displacement device that converts energy, namely positive displacement compressors that rotate in a single rotational direction to displace working fluid contained in operating chambers. The device described herein is particularity advantageous for the ability to achieve high compression ratios in combination with high discharge pressure and high volumetric throughput in a single stage.

A pair of co-operating screw rotors including a male rotor and a female rotor. The male rotor and the female rotor have helically extending lobes and intermediate grooves configured to intermesh with one another. Each groove of the female rotor has a first flank including at least three concave sections. A first section includes or is disposed immediately adjacent the radially innermost point of the groove. A second section is shaped as a circular arc with a radius having its center located outside the pitch circle. A third section is shaped as a circular arc with a radius having its center located outside the pitch circle. The radius of the third section is greater than the radius of the second section, which is greater than the radial distance between a pitch circle of the female rotor and the radially innermost point of the groove.

A motor includes a shaft rotatable about an axis, an engaged component engaged by the shaft, a sleeve fixed to the shaft to rotate therewith, and a seal at least partly circumscribing the shaft. The shaft includes an engagement region presenting a substantially variable outer shaft surface that at least in part engages the engaged component. The sleeve includes a first section that at least partly circumscribes and engages the engagement region of the shaft. The first section of the sleeve presents an outer seal-engaging surface and an outer bearing-engaging surface. The seal and the bearing each at least partly circumscribe the engagement region of the shaft and the first section of the sleeve to engage the seal-engaging surface and the bearing-engaging surfaces, respectively, of the sleeve.

A rotor pair for a compressor block of a screw machine includes a secondary rotor that rotates about a first axis and a main rotor that rotates about a second axis. The number of teeth of the main rotor is 3 and the number of teeth of the secondary rotor is 4. The relative profile depth of the secondary rotor is at least 0.5 rk1 is an addendum circle radius drawn around the outer circumference of the secondary rotor and rf1 is a dedendum circle radius starting at the profile base of the secondary rotor. The ratio of the axis distance of the first axis from the second axis and the addendum circle radius rk1 is at least 1.636.

The present invention relates to highly efficient suction and compression rotating mechanisms, particularly the compression mechanism with piston blocks mounted on two axes and driven by a pair of matching gears in the field of compressors and vacuums or hydraulic system such as oil pump, hydraulic motor, hydraulic gearbox, specifically there is application that uses this mechanism to create one rotary motor with multi compression stages, force-generating stages and continuous fuel burning regime. The new rotary lobe structure in this invention provides a close contact between curved surfaces with the same radius, which is a “Surface -to-surface” contact, whith much better tightness than “line” contact.

An electric pump includes a housing that includes a gear chamber, a rotor chamber, and a motor chamber. The electric pump includes a first seal member, a second seal member, and a third seal member. The first seal member seals a space between the gear chamber and the rotor chamber. The second seal member seals the space between the gear chamber and the rotor chamber. The third seal member seals a space between the gear chamber and the motor chamber. The third seal member seals the space between the gear chamber and the motor chamber to a lesser extent than the first seal member and the second seal member seal the space between the gear chamber and the rotor chamber.

The invention relates to a rotor pair for a compressor block of a screw machine, wherein the rotor pair comprises a secondary rotor that rotates about a first axis and a main rotor that rotates about a second axis, wherein the number of teeth of the main rotor is 3 and the number of teeth of the secondary rotor is 4. The relative profile depth of the secondary rotor is at least 0.5, preferably at least 0.515, and at most 0.65, preferably at most 0.595. rk1 is an addendum circle radius drawn around the outer circumference of the secondary rotor and rf1 is a dedendum circle radius starting at the profile base of the secondary rotor, wherein the ratio of the axis distance of the first axis from the second axis and the addendum circle radius rk1 is at least 1.636, and at most 1.8, preferably at most 1.733.

The invention relates to a bi-helical toothed wheel (1) with non-encapsulating profile for a hydraulic gear apparatus, of the type bound to a support shaft (5) to form a driving or driven wheel of the hydraulic apparatus and comprising a plurality of teeth (6) extended with variable helix angle with continuous function in the longitudinal direction, wherein the teeth profile keeps a shape continuity in each cross section thereof. More particularly, each tooth of the toothed wheel is longitudinally split in three zones: initial (A), central (B) and terminal (C) zones, and the central zone (B) has a variable helix angle, while the initial (A) and terminal (c) zones have a constant helix angle. The invention allows to manufacture contra-rotating rotors, having a non-encapsulating profile and a helix shape such as to suppress the angular point at the center of the rotors themselves and therefore all the problems related to their machining.

The invention reduces a pressure or thermal effect while reducing the mass of a screw rotor. There is provided a screw rotor having a helical tooth on an outer periphery, the helical tooth extending by a predetermined length in an axial direction, in which a radial cross section of the screw rotor includes a lobe portion having a predetermined thickness in a direction toward an axis and forming the helical tooth, and a hollow portion extending from an axial side inner surface of the lobe portion toward an axial side, and the predetermined thickness of the lobe portion differs between a high load side on the outer periphery of the screw rotor and a low load side on the outer periphery.