Piston machine, especially fluid piston machine

Abstract

A piston machine, in particular a fluid piston machine, is described as having a plurality of piston units, which have differently sized output volumes for reasons of geometry, and are able to be deactivated individually for the discrete adjustment of a total output volume of the piston machine. In this context, the larger output volume of one of the piston units is twice as high as the next smaller output volume of one of the other piston units.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a piston machine, especially a fluid piston machine, having a plurality of piston units which, for reasons of geometry, have output volumes of different size, and which are able to be deactivated individually for the discrete adjustment of an overall output volume of the piston machine.BACKGROUND INFORMATION[0002]Piston machines of the type described at the outset are known from the related art. In many technological fields piston machines are used as pumps and / or motors. Different principles are known for generating a variable volumetric flow or volume flow, possibly also a variable pressure (pump) or rotational speed and torque (motor). Conventional types for the continuous variation / setting of the output volume of the piston units are, for example, piston machines having a swash plate, an oblique axis or a wobble plate. By changing the angle, the upper and lower dead centers of the piston strokes are varied and the outp...

AI Technical Summary

Benefits of technology

[0004]The piston machine according to the exemplary embodiments and / or exemplary methods of the present invention has the features described herein. Accordingly, the piston machine is developed in such a way that the larger output volume of one of the piston units is twice as large as the next smaller output volume of one of the other piston units. That is to say, the piston units have output volumes of different sizes, and the piston unit having a greater output volume is designed such that its output volume is twice as large as that of the other piston unit having the next smaller output volume. For example, when three piston units are provided, the output volume of the second piston unit is twice as high as that of the first, and the output volume of the third piston unit is twice as high as that of the second piston unit. This applies analogously to any other number of piston units of the piston machine. This makes it possible to vary or adjust the total output volume of the piston machine in discrete manner in equidistant stages.

[0005]In the aforementioned exemplary embodiment featuring three piston units, it is possible to adjust eight different total output volumes, from zero to seven times the output volume of the piston unit having the smallest output volume. For practical purposes, the piston units are configured in such a way that the stage in the increase or reduction of the total output volume in each case corresponds to the output volume of the piston unit having the smallest output volume. This creates a piston machine whose total output volume is variably adjustable in equidistant stages and which provides high efficiency even in partial-load range.

[0006]Furthermore, each piston unit is assigned a switchable drain valve for deactivating the piston unit. The drain valve is designed such that opening of the drain valve prevents pressure from being generated in the piston unit, thereby preventing the supply of fluid. The drain valve thus allows the volume contained in the piston unit to “run dry”.

Problems solved by technology

However, such constructions have low efficiency, especially in the partial-load range.

This low efficiency essentially is due to the leakage at the corresponding control, oblique or swash plate, the friction at the control / oblique or swash plate as well as a constantly required control current for supporting the control / oblique or swash plate.

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