Displacement pump with variable volume flow

Abstract

A displacement pump with variable volume flow having a casing; a chamber with an inlet opening on a low pressure side and an outlet opening on a high pressure side for a fluid; an internal rotor capable of rotation about a rotational axis (DI); a ring having a central ring axis (DA) surrounding the internal rotor and forming together with the ring, at least one delivery cell in which fluid is delivered from a low pressure side to a high pressure side of the pump; and an adjusting device which, during an adjusting movement, rolls off on the casing without slipping is provided. The internal rotor is fixed to the adjusting device and rotatble about the rotational axis (DI), and the position of the rotational axis (DI) relative to the central ring axis (DA) of the ring is adjusted by the adjusting movement of the adjusting device.

Description

FIELD OF THE INVENTION [0001] The invention relates to displacement pumps, in particular internal-axle gear pumps, but also wing cell pumps or for example also pendulum slider pumps, whose volume flow can be varied according to requirement, i.e. can be adjusted. The pumps in accordance with the invention are preferably used as lubricant oil pumps for internal combustion engines, wherein the internal combustion engine itself preferably drives the lubricant oil pump in question. The internal combustion engine can in particular be a drive motor, preferably a piston motor, of a vehicle. The specific volume flow, i.e. the volume flow delivered per revolution of a delivery wheel of the pump, can preferably be adjusted continuously. The displacement pumps can also be advantageously used as supply pumps for automatic transmissions in vehicles and when used in this way are also preferably driven by the drive motor of the vehicle in question. Although the displacement pump of the invention, w...

AI Technical Summary

Benefits of technology

[0007] By adjusting the internal rotor relative to the casing and the surrounding ring in order to adjust the specific volume flow, sealing the delivery space formed between the internal rotor and the outer ring can be simplified.

[0018] No eccentric chucks are required for machining the casing parts, since the shaft and external rotor bearings are concentric. The depth of the internal toothing of the casing is minimised and no longer has to be machined over the entire running set width, as with the known design. This toothing can be high-precision manufactured on a CNC machine with a C axis and path-controlled HSC (high speed cutting) spindle unit in a clamp together with the other machining operations. This results in a considerable reduction in the expenditure of time for machining the toothing of the casing.

Problems solved by technology

However, it has proven in practice that the design space available in increasingly compact reciprocating piston motors is becoming smaller and smaller.

Since these pumps are preferably arranged in the oil sump of the crankcases and since a mass-balance shaft often also has to be additionally accommodated in this region, together with other influencing factors such as conductor frame fortification of the crankcase and a highly pitched oil pan for ground clearance and the arrangement of the vehicle steering parts, the outer diameter of the variable pump is too large.

Since, due to the heated idling at low motor speed, the pump has to exhibit a specific minimum delivery amount, the diameter of the gear ring running set cannot be arbitrarily reduced.

Wide running sets have the additional disadvantage that during speed regulation, the overthrust losses between the converging and diverging teeth cells caused by differential varying are very high.

Images