Rotary Piston Machine Compact Housing Design

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Solution Overview

Problem

Existing rotary piston machines for pumps, compressors, or motors have a bulky housing design that is difficult to manufacture and requires separate hemispherical housing parts, leading to inefficiencies in sealing and increased peripheral speeds of fluid transport.

Innovation Solution

A rotary piston machine design with a rotor and counter-rotor arrangement where the axes of rotation enclose an angle less than 45°, reducing the outer diameter by 50% or more, allowing for a one-piece housing with integrated sealing and lower peripheral speeds, and featuring multiple working spaces for multi-stage compression and flow control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the housing is divided into two hemispherical parts with separate center points, then assembly is facilitated, but the sealing complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvehousing assemblyVSAvoidsealing structure
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the two separate hemispherical housing parts into a single monoblock housing structure. This eliminates the need for complex sealing between two halves while maintaining the spherical geometry needed for the rotor-counter-rotor mechanism. The single housing structure with integrated sealing surfaces directly resolves the contradiction by simplifying both manufacturing and sealing complexity.

Inventive Principle:
Principle #5Merging (Combining)

2Area of stationary object

If the angle between the second extension and the second axis of rotation is reduced to less than 45°, then the outer diameter of the toothing is reduced by 50% or more, but the housing length increases

Engineering Contradiction:
Improvehousing diameterVSAvoidhousing length
Core Design Contradiction:
Area of stationary objectVSLength of stationary object

Solution Approach 1:

The patent changes the critical geometric parameter - the angle between the second extension of the tooth base surface line and the second axis of rotation - from the conventional larger angle to less than 45°. This parameter change fundamentally alters the spatial arrangement of the toothing, enabling a 50% or more reduction in outer diameter while accepting an increase in housing length as a necessary trade-off for achieving compact radial dimensions.

Inventive Principle:
Principle #35Parameter changes

3Area of stationary object

If the rotor-counter-rotor arrangement is designed with smaller outer diameter, then the housing diameter is reduced, but the teeth length increases

Engineering Contradiction:
Improvehousing diameterVSAvoidtooth length
Core Design Contradiction:
Area of stationary objectVSLength of moving object

Solution Approach 1:

The patent transitions from a conventional radial tooth arrangement to a configuration where teeth are arranged at inclined angles relative to the rotation axes. By introducing angular dimensions and orienting teeth along inclined surface lines that intersect at the common center point, the design achieves compact radial dimensions while accommodating longer tooth lengths in the axial and angular directions, effectively redistributing dimensional requirements across different spatial dimensions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Loss of energy

If the peripheral speed of the teeth is reduced, then energy loss is reduced, but the housing must accommodate longer teeth

Engineering Contradiction:
Improveperipheral speed lossVSAvoidtooth length
Core Design Contradiction:
Loss of energyVSLength of moving object

Solution Approach 1:

The patent changes the geometric parameters of the rotor-counter-rotor system, specifically the angle between rotation axes and the arrangement of tooth surface lines, to achieve a more favorable velocity distribution. This parameter optimization reduces the peripheral speed of teeth and transported fluid, thereby reducing energy losses, while the accompanying increase in tooth length is accommodated by the redesigned housing structure.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2655802B1Gear machine with a small diameter-to-length ratio
Publication Date: 2015.04.15 ROBERT BOSCH GMBH
  • EP2655802B1 patent drawingFigure 1~2
  • EP2655802B1 patent drawingFigure 3~4
  • EP2655802B1 patent drawingFigure 5~6

AI summary

The invention relates to a rotary piston machine which operates as a pump, a compressor, or a motor and which has a rotor (2) and a counter rotor (4), said counter rotor (4) being disposed opposite the rotor (2). The rotor (2) has a first end surface (6) with a first toothing system (8). The counter rotor (4) has a second end surface (16) with a second toothing system (18). The first toothing system (8) is made of at least one first tooth (10) and a first tooth space (12). The second toothing system (18) is made of at least one second tooth (20) and a second tooth space (22) with a second tooth base (24). The toothing systems (8, 18) are in engagement with each other such that first working chambers (28) are formed by means of the meshing of the first teeth (10) of the first toothing system (8) and the second teeth (20) of the second toothing system (18), wherein volumes that are formed by the first working chambers (28) are changed by means of the meshing of the teeth (10, 20). The rotor (2) has a first rotational axis (I), and the counter rotor (4) has a second rotational axis (II). The first rotational axis (I) and the second rotational axis (II) enclose a first angle (φ) that is not equal to 0°. A second extension (26) of a second surface line of the second tooth base (24), the first rotational axis (I), and the second rotational axis (II) intersect at a common central point (M). According to the invention, a second angle (β) that is enclosed between the second extension (26) and the second rotational axis (II) is smaller than 45°.