Swivel Angle Measuring Device for Hydrostatic Piston Machine

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing rotary swivel angle measuring devices for hydrostatic axial piston machines with adjustable stroke volume require significant design space and are prone to jamming due to the radial movement of the return lever and the conversion of wide piston movements into small rotational encoder movements.

Innovation Solution

A translational swivel angle measuring device is implemented, where a permanent magnet is moved linearly and translationally by the adjustment piston along its direction of movement via a magnet coupling device, eliminating the need for radial movement and allowing for undiminished linear movement of the encoder.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a rotary swivel angle measuring device is used with radial movement of the return lever, then the swivel angle can be detected, but the design space requirement increases and the risk of jamming increases

Engineering Contradiction:

Improveswivel angle detectionVSAvoiddesign space requirement

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent replaces the rotary mechanical encoder system with a linear magnetic field-based measurement system. The permanent magnet moves linearly with the adjustment piston, and the Hall sensor detects the magnetic field changes to determine the swivel angle, eliminating the need for complex rotary mechanical components and reducing design space requirements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transitions from rotary movement in one dimension to linear movement in another dimension. The return lever's radial rotary movement is replaced by linear axial movement of the permanent magnet, which moves parallel to the adjustment piston's direction of movement, thereby reducing the required design space.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Measurement precision

If wide piston movements are converted into small rotational encoder movements, then the swivel angle detection is achieved, but the risk of jamming increases

Engineering Contradiction:

Improveswivel angle detectionVSAvoidrisk of jamming

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent eliminates the mechanical rotary encoder and its associated jamming risks by using a magnetic field-based linear measurement system. The Hall sensor detects the position of the permanent magnet through magnetic field changes, providing a non-contact measurement method that is free from mechanical friction and jamming.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces the magnetic field as an intermediary between the moving permanent magnet and the stationary Hall sensor. This magnetic field mediator allows for contactless transmission of position information, eliminating the need for direct mechanical contact and thereby preventing jamming.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If the return lever and encoder magnet holder are designed with increased design space, then the swivel angle measurement can be implemented, but the overall device complexity increases

Engineering Contradiction:

Improveswivel angle detectionVSAvoidbearing and holder design

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the functions of the return lever and encoder magnet holder into a single integrated component. The permanent magnet is mounted on the return lever itself, eliminating the need for separate holders and bearings, thereby reducing device complexity while maintaining measurement functionality.

Inventive Principle:

Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution reduces the risk of jamming and minimizes design space requirements by converting wide piston movements into wide translational movements of the encoder, ensuring accurate swivel angle detection.

Implementation Method 1

the permanent magnet is guided past the transducer in a translational relative movement. For this purpose, the permanent magnet can be moved linearly and translationally by the adjustment piston along its direction of movement by way of a magnet coupling device

Methodology Applied

Scientific EffectMagnetic coupling: Magnetism

Implementation Method 2

a transducer (preferably a Hall sensor) fixed to the housing

Methodology Applied

Scientific EffectHall effect: Hall Effect

Data Source

PatentUS20250059963A1Swivel Angle Measuring Device on a Hydrostatic Axial Piston Machine with Variable Stroke Volume

Publication Date: 2025.02.20 ROBERT BOSCH GMBH

AI summary

A swivel angle measuring device and a hydrostatic axial piston machine are disclosed having a swashplate, the swivel angle of which can be adjusted by way of an adjustment piston guided in an adjustment cylinder, and having a swivel angle measuring device, by way of which the swivel angle of the swashplate can be detected. The swivel angle measuring device includes a movable encoder formed by a permanent magnet and a transducer fixed to the housing. The swivel angle measuring device is translational, wherein the permanent magnet can be moved linearly and translationally by the adjustment piston along its direction of movement by way of a magnet coupling device.