Damper Piston Hole for Redundant Thrust Reduction

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Solution Overview

Problem

In damper devices with a piston-cylinder mechanism, the difference in pressure-receiving areas between gas chambers leads to redundant thrust, degrading the damper's performance, especially when operating with high-pressure gas.

Innovation Solution

The damper device features a piston head with a circular outer shape and a hole with a circular bottom, where the pressure-receiving areas are optimized by the difference between the outer diameter of the piston head and the inner/outer diameters of the hole and rod, connected through a variable aperture that adjusts with external acceleration, reducing the pressure-receiving area difference and minimizing redundant thrust.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a piston rod is placed in one of the two gas chambers, then the damper device can be compact and operational, but a difference in pressure-receiving areas is produced leading to redundant thrust

Engineering Contradiction:
Improvecompact structureVSAvoidredundant thrust
Core Design Contradiction:
Volume of moving objectVSForce

Solution Approach 1:

The patent extracts the harmful effect (redundant thrust) by introducing a through-hole in the piston head that allows pressure equalization between the two gas chambers. This removes the imbalance caused by the piston rod occupying space in one chamber, eliminating the redundant thrust while maintaining the compact structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The through-hole in the piston head acts as an intermediary channel that mediates the pressure difference between the two gas chambers. By allowing gas to flow through this intermediary pathway, the pressure imbalance is corrected and redundant thrust is eliminated.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If high-pressure gas is used to reduce damper size and improve responsiveness, then the damper size is reduced and responsiveness is improved, but the redundant thrust becomes larger

Engineering Contradiction:
Improvedamper sizeVSAvoidredundant thrust
Core Design Contradiction:
Volume of moving objectVSForce

Solution Approach 1:

The patent extracts the harmful redundant thrust effect by providing a pressure equalization pathway through the through-hole in the piston head. This allows the system to utilize high-pressure gas for compact size and improved responsiveness while simultaneously removing the pressure imbalance that would otherwise create excessive redundant thrust.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If the piston head has a simple circular shape, then manufacturing is easy, but the pressure-receiving area difference cannot be optimized

Engineering Contradiction:
Improvepiston head manufacturingVSAvoidpressure-receiving area difference
Core Design Contradiction:
Ease of manufactureVSForce

Solution Approach 1:

The patent segments the piston head structure by introducing a through-hole that divides the pressure-receiving surfaces. This segmentation allows the simple circular outer shape to be maintained for ease of manufacture, while the internal through-hole creates optimized pressure distribution that reduces the effective pressure-receiving area difference.

Inventive Principle:
Principle #1Segmentation

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 configuration significantly reduces the pressure-receiving area difference, suppressing redundant thrust and enabling effective operation with high-pressure gas, while allowing for semi-active damper functionality by adjusting the aperture according to external accelerations, thereby enhancing the damper's performance and reducing torsional stress on vehicles.

Implementation Method 1

a guide shaft which has a tip having an outer peripheral surface that slides on an inner wall surface of the hole with the bottom is provided in the piston head

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the two gas chambers act as a damper with respect to a movement of the piston

Methodology Applied
Scientific EffectDamping: Damping

Implementation Method 3

a piston rod is placed in one of the two gas chambers, a difference is produced in pressure-receiving areas of the piston facing the two gas chambers

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP3061986B1Damper device
Publication Date: 2020.08.05 PNEUMATIC SERVO CONTROLS LTD
  • EP3061986B1 patent drawingFigure 1
  • EP3061986B1 patent drawingFigure 2
  • EP3061986B1 patent drawingFigure 3(a)~3(c)

AI summary

The present invention addresses the problem of minimizing the difference between the pressure-receiving surface areas of two gas chambers that are demarcated by a piston unit in a damper device which uses a piston cylinder mechanism. This damper device (20) is equipped with: a cylinder unit (22) having a sliding inner wall surface; a piston unit (26), having a piston head (28), which has an outer diameter part that slides on the sliding inner wall surface of the cylinder unit (22), and divides the interior space of the cylinder unit (22) into a first gas chamber (38) and a second gas chamber (40), a rod (32) extending from the second gas chamber (40) side of the piston head (28), and a closed-end hole (34) which opens toward the first air chamber (38) side of the piston head (28) and extends through the interior of the rod (32) in the direction of the second air chamber (40); and a guide shaft (42) affixed to the first gas chamber (38) side of the cylinder unit (22) and equipped with a tip part (48) having an outer circumferential surface that slides on the inner wall surface of the closed-end hole (34) of the piston unit (26).