Axial Piston Machine Proportional Adjustment Feedback
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Solution Overview
Problem
Existing axial piston machines face issues with mechanical hysteresis and large adjustment device sizes due to lever and spring systems, which affect proportional adjustment and increase the risk of damage to proportional magnets, especially in machines with small volumetric displacement and limited installation space.
Innovation Solution
The axial piston machine employs a feedback device with spring levers mounted on bearing shells and a two-armed pointer lever system that pivots about a common axis, reducing tilting moments and friction, allowing for precise and compact adjustment of the swashplate position using proportional magnets acting on a control piston along a common tappet axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a lever and spring system is used for mechanical feedback, then the swashplate position can be fed back to the control piston, but mechanical hysteresis adversely affects the proportional adjustment characteristic
Solution Approach 1:
The patent replaces the traditional lever and spring mechanical feedback system with a magnetic field-based feedback mechanism. The first and second magnets generate magnetic fields that act directly on the control piston, eliminating the need for mechanical levers and springs. This substitution removes the source of mechanical hysteresis while maintaining the feedback function, as the magnetic fields directly transmit the swashplate position information to the control piston without mechanical intermediate components.
2Manufacturing precision
If differently dimensioned adjustment devices are used for different axial piston machine sizes, then each machine can have optimized adjustment, but the overall width increases and proportional magnets must be mounted farther apart
Solution Approach 1:
The patent creates a universal adjustment device design where the control piston with its magnetic field-based feedback mechanism can be scaled and applied to axial piston machines of different sizes. The proportional magnets are mounted on the control piston itself, allowing the same fundamental design to be used across different machine dimensions without requiring differently dimensioned adjustment devices. This universality reduces the overall width requirement while maintaining manufacturing precision.
3Ease of operation
If proportional magnets are mounted at an exposed location on the axial piston machine, then the adjustment function is achieved, but the risk of damage increases
Solution Approach 1:
The patent merges the proportional magnets with the control piston structure. The first and second magnets are integrated into the control piston assembly, which is positioned within the hydraulic system's internal architecture. This integration protects the magnets from external damage while they continue to perform their adjustment function by generating magnetic fields that control the oil pressure and swashplate position.
4Volume of stationary object
If the axial piston machine has small volumetric displacement and correspondingly small installation space, then compactness is achieved, but there is insufficient space for traditional adjustment devices
Solution Approach 1:
The patent implements a nested arrangement where the proportional magnets are mounted on the control piston itself, which is positioned within the existing hydraulic system architecture. The magnetic feedback mechanism is nested within the control piston assembly, allowing the adjustment device to function within the limited installation space of small volumetric displacement machines without compromising operational capability.
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 enables a compact, precise, and robust adjustment system that can be used across a range of axial piston machines with different volumetric displacements, eliminating the need for multiple adjustment devices and reducing the risk of damage to proportional magnets.
Implementation Method 1
The control piston is adjusted by means of at least one proportional magnet which can be activated electrically and which acts on the control piston along a common tappet axis
Implementation Method 2
The feedback device comprises spring levers which can pivot about an axis. The spring levers are each mounted on the pivot axis with a bearing shell
Implementation Method 3
The spring levers are each mounted on the pivot axis with a bearing shell, which are each composed of two component shells which support the spring lever at separate locations on the pivot axis
Data Source
AI summary
An axial piston machine having a swashplate or an oblique axis which can be adjusted by means of servopistons and has a valve segment and an adjustment unit for the electrically proportional adjustment of the volumetric displacement. The adjustment unit comprises proportional magnets which can be activated electrically, and a control piston for controlling the oil pressure which moves the servopistons. The proportional magnets act on the control piston along a common tappet axis, a feedback device for feeding back the current swashplate or oblique-axis valve-segment position to the control piston being provided. The feedback device comprises spring levers 6, 6′ which can pivot about an axis, the spring levers 6, 6′ each being mounted on the pivot axis 5 with a bearing shell 15, which are each composed of two component shells which support the spring lever 6, 6′ at separate locations on the pivot axis 5, and which each essentially enclose a half-space about the pivot axis 5.