Coil-Spring Position Sensing for Simpler Fluid Pressure Control

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Solution Overview

Problem

Existing position sensors and fluid pressure systems, such as those in Patent Literatures 1 and 2, are complex, costly, and not well-suited for integration into fluid pressure systems due to the use of mechanical displacement sensors, self-pumps, and solenoid valves, which complicate configuration and increase costs.

Innovation Solution

A position sensor utilizing a coil spring to bias a movable member within a fluid storage housing, generating an electrical signal based on the member's movement, integrated with a fluid pressure system that includes a pump capable of forward and reverse rotation, controlled by a control unit to switch between rotation directions based on the sensor's output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a mechanical displacement sensor is provided in the vicinity of a jack for vehicle height adjustment, then the displacement can be detected, but the configuration becomes slightly complicated

Engineering Contradiction:
Improvedisplacement detection accuracyVSAvoidsystem configuration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the displacement sensor with the reservoir structure, merging two separate components into one integrated unit. The sensor is housed within the reservoir, eliminating the need for separate mounting structures and reducing overall system complexity while maintaining displacement detection functionality

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The reservoir serves multiple functions: it stores fluid and houses the displacement sensor. This multi-functional design reduces the number of separate components needed in the system, simplifying the overall configuration while maintaining all necessary functions

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of manufacture

If a self-pump using mechanical vibration is used as a drive source for oil, then the pump can operate without external power, but it is a disadvantage for electrification

Engineering Contradiction:
Improvepump operation simplicityVSAvoidelectrification compatibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical vibration-based self-pump with an electric pump that can be controlled through electrical signals. This substitution enables the system to be electrified and integrated with modern vehicle electrical architectures while maintaining pump functionality

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If a solenoid valve is used to switch the path through which oil flows, then the flow path can be controlled, but expensive coils and complex control systems are required

Engineering Contradiction:
Improveflow path control capabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent removes the solenoid valve and its associated control system from the design. Instead of using an electrically-controlled valve, the system uses a check valve that operates passively based on pressure differential, eliminating the need for expensive coils and complex electronic control while maintaining flow path switching capability

Inventive Principle:
Principle #2Taking out (Extraction)

4Measurement precision

If a coil serving as an electronic component is used for the stroke sensor, then the sensor can provide electrical output, but an increase in cost is expected

Engineering Contradiction:
Improvedisplacement measurement capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent uses a simple variable inductance sensor based on a coil spring instead of expensive electronic stroke sensors. The coil spring's inductance changes with compression, providing a low-cost displacement measurement solution that eliminates the need for costly electronic sensors while maintaining measurement functionality

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 simplifies the configuration of fluid pressure systems, reduces costs by eliminating expensive electronic components, and enhances design freedom, making it suitable for electric vehicles.

Implementation Method 1

a control board configured to feed a current through the coil spring to generate a magnetic field, in which an electrical signal fluctuating according to a movement of the movable member is output from the coil spring

Methodology Applied
Scientific EffectMagnetic field generation: Electromagnetic Induction

Implementation Method 2

a movable member provided in a housing and allowed to reciprocate by receiving a pressure from a fluid in the housing or pressing the fluid; a coil spring configured to bias the movable member

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnet

Data Source

PatentEP4647714A1Position sensor and fluid pressure system
Publication Date: 2025.11.12 ASTEMO LTD
  • EP4647714A1 patent drawingFigure 1
  • EP4647714A1 patent drawingFigure 2
  • EP4647714A1 patent drawingFigure 3

AI summary

A position sensor (SE) has a movable member (63) provided in a housing (61) and allowed to reciprocate by receiving a pressure from a fluid in the housing (61) or pressing the fluid, a coil spring (68) configured to bias the movable member (63), and a control board (64) configured to feed a current through the coil spring (68) to generate a magnetic field. An electrical signal (F-Iout) fluctuating according to a movement of the movable member (63) is output from the coil spring (68).