Hydraulic Piston Zeroing Device Fatigue Resistance

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Solution Overview

Problem

Existing zeroing devices for hydraulic pistons often rely on return springs that experience material fatigue over time, leading to inaccuracies in defining the zero position of the piston.

Innovation Solution

A zeroing device comprising a piston, biasing members, and an axially displaceable zeroing member that limits the axial movement of the biasing members, allowing for precise setting of the zero position through axial displacement of the zeroing member.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If return springs are used to return the piston to its zero position, then the zero position can be defined, but material fatigue over time impairs the accuracy of the zero position definition

Engineering Contradiction:

Improvezero position accuracyVSAvoidservice life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent extracts the zero-position-defining function from the return spring system. A separate zeroing device with a zeroing member is introduced that can independently define the zero position without relying on the elastic properties of the return spring. This separates the functions of returning the piston (spring) and defining zero position (zeroing member), eliminating the accuracy degradation caused by spring fatigue.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The zeroing member is pre-adjustable to set the zero position before operation begins. By preliminarily positioning the zeroing member at the desired zero location, the system establishes an accurate reference point that remains stable throughout operation, independent of spring condition. This preliminary setup ensures accurate zero positioning from the start and maintains it over the service life.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If a zeroing member is introduced to define the zero position independently, then zero position accuracy is improved, but device complexity increases

Engineering Contradiction:

Improvezero position accuracyVSAvoidstructure complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The zeroing member is integrated into the existing piston assembly structure. It combines with the return spring and piston body to form a unified zeroing device that leverages existing spatial relationships and mounting points. This merging approach adds the zero-position-defining capability without requiring a completely separate mechanism, thereby limiting the increase in overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The zeroing member is designed to perform multiple functions: it defines the zero position, can be adjusted for calibration, and works in conjunction with the return spring system. This multi-functionality reduces the need for additional dedicated components, as the zeroing member serves as both a positioning element and a calibration reference, thereby minimizing the complexity increase.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS12313060B2Zeroing device

Publication Date: 2025.05.27 DPC HYDRAULICS SRL

AI summary

The present disclosure relates to a zeroing device comprising a piston movable along an axis, at least one biasing member for biasing the piston along the axis, and an axially displaceable zeroing member limiting axial movement of the at least one biasing member. The present disclosure further relates to a variable displacement hydraulic unit including said zeroing device.