Magnetic Encoder Shielding for Axial Piston Pump Position Monitoring
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Solution Overview
Problem
Existing axial piston pump monitoring systems using magnetic encoders are disrupted by the movement of ferromagnetic pistons and are sensitive to maladjustments, leading to non-linearities in measurement.
Innovation Solution
A magnetic encoder with at least two permanent magnets arranged on a ferromagnetic plate, where each magnet's pole is partially or fully covered by the plate, minimizes interference from piston movement and allows for easy differentiation and compensation of maladjustments, ensuring the system is compact and balanced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a magnetic encoder is attached to the swash plate to monitor angular position, then monitoring capability is improved, but measurement precision deteriorates due to interference from ferromagnetic piston movement
Solution Approach 1:
A non-ferromagnetic plate is introduced as an intermediary component between the ferromagnetic pistons and the permanent magnets of the magnetic encoder. This plate acts as a magnetic shield that blocks the interfering magnetic field lines generated by piston movement, preventing them from reaching the encoder sensor. The plate material (such as aluminum or plastic) is specifically chosen to be non-ferromagnetic, creating a barrier that allows accurate angular position measurement while the pistons move freely.
2Reliability
If magnets are arranged on the swash plate for monitoring, then monitoring capability is improved, but device complexity increases due to firm installation requirements
Solution Approach 1:
The magnetic encoder components (permanent magnets, plate, and sensor mounting structure) are merged into a single integrated assembly that is designed to be mounted as one unit on the swash plate. This integration eliminates the need for separate installation steps for each component and reduces the number of fastening points required. The assembly can be securely attached using simple mounting brackets or adhesive, significantly reducing installation complexity while maintaining monitoring reliability.
3Ease of manufacture
If a magnetic encoder with uncovered poles is used, then manufacturing is simplified, but measurement precision deteriorates due to sensitivity to maladjustments and non-linearities
Solution Approach 1:
The plate is designed with differentiated local qualities: the regions corresponding to the permanent magnet poles are covered by non-ferromagnetic material, while other areas may have different properties. This selective covering ensures that the critical pole areas are protected from piston interference, maintaining measurement precision. The plate thickness and material distribution are optimized locally to provide adequate shielding exactly where needed, without unnecessarily complicating the overall manufacturing process.
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
The solution effectively shields the magnetic field sensor from piston movement interference and reduces non-linearities, enabling accurate and reliable monitoring of the axial piston pump's operation with minimal installation space and weight imbalance.
Implementation Method 1
A magnetic encoder with at least two permanent magnets arranged on a ferromagnetic plate
Implementation Method 2
a plate consisting of a ferromagnetic material
Data Source
AI summary
An axial piston pump having several pistons has a magnetic encoder (5), which is arranged on a swash plate, and a magnetic field sensor, which is arranged in such a way that it faces towards the magnetic encoder (5). The magnetic encoder (5) has at least two permanent magnets (2, 3) and a plate (4) which consists of a ferromagnetic material. The permanent magnets (2, 3) are arranged on the plate (4) in such a way that they each faces a magnetic pole towards the plate (4), and this pole is at least partially covered by the plate (4) in each case.