Shock Absorber Seal Member Rigidity Under Pilot Chamber Pressure

Solution Overview

Problem

The durability of seal members in shock absorbers is compromised by high pressures in the pilot chamber, leading to unstable sliding and inconsistent damping force characteristics.

Innovation Solution

A shock absorber design featuring an annular seal member with an outer concave portion and an inner convex portion, where the convex portion protrudes radially outward, enhancing the seal member's rigidity and preventing abnormal deformation, thereby improving durability and maintaining stable damping force characteristics under high pressures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the seal member is made flexible to ensure sealing, then sealing performance is improved, but durability deteriorates under high pressure

Engineering Contradiction:

Improvesealing performanceVSAvoiddurability

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The seal member is constructed as a composite structure combining a resilient sealing portion (made of elastomer) with a rigid reinforcement portion (made of metal or rigid plastic). This composite design allows the sealing surface to maintain flexibility for effective sealing while the rigid reinforcement provides structural strength to resist high pressures and improve durability.

Inventive Principle:

Principle #40Composite materials

2Duration of action of stationary object

If the seal member is made rigid to improve durability, then durability is improved, but sliding stability deteriorates

Engineering Contradiction:

ImprovedurabilityVSAvoidsliding stability

Core Design Contradiction:

Duration of action of stationary objectVSStability of the object's composition

Solution Approach 1:

The seal member is constructed as a composite structure combining a resilient sealing portion (made of elastomer) with a rigid reinforcement portion (made of metal or rigid plastic). This composite design allows the sealing surface to maintain flexibility for effective sealing while the rigid reinforcement provides structural strength to resist high pressures and improve durability.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If the seal member structure is simplified, then manufacturing ease is improved, but durability under high pressure deteriorates

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoiddurability

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The seal member is constructed as a composite structure combining a resilient sealing portion (made of elastomer) with a rigid reinforcement portion (made of metal or rigid plastic). This composite design allows the sealing surface to maintain flexibility for effective sealing while the rigid reinforcement provides structural strength to resist high pressures and improve durability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The seal member employs a flexible elastomeric sealing portion that can deform to maintain sealing contact, combined with a rigid reinforcement structure. The flexible material allows the seal to adapt to surface irregularities and maintain sealing effectiveness while the rigid reinforcement prevents abnormal deformation under high pressure.

Inventive Principle:

Principle #30Flexible shells and thin films

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 design significantly enhances the durability of the seal member, ensuring smooth sliding and consistent damping force characteristics even under increased pressures, stabilizing the damping force and improving the shock absorber's performance.

Implementation Method 1

an annular seal member that is provided to be fixed to the outer circumferential side of a rear surface of the damping valve, and is fitted into a tube of the pilot case so as to be slidable and to be in a liquid tight manner

Methodology Applied

Scientific EffectSealing:

Implementation Method 2

a bottomed tubular pilot case that forms a pilot chamber that causes pressure to act on the damping valve in a valve closing direction

Methodology Applied

Scientific EffectPressure: Pressure Increase

Implementation Method 3

a damping valve that suppresses a flow of the operating fluid due to the sliding of the piston to generate damping force

Methodology Applied

Scientific EffectFluid resistance: Drag

Data Source

PatentUS9868331B2Shock absorber

Publication Date: 2018.01.16 ASTEMO LTD

AI summary

A shock absorber includes: a damping valve that suppresses a flow of operating fluid due to the sliding of a piston to generate damping force; a bottomed tubular pilot case that forms a pilot chamber that causes pressure to act on the damping valve in a valve closing direction, together with the damping valve; and an annular seal member (146) that is provided to be fixed to the outer circumferential side of a rear surface of the damping valve, and is fitted into a tube of the pilot case so as to be slidable and to be in a liquid tight manner. A part of the flow of the operating fluid is guided to the pilot chamber and opening of the damping valve is suppressed by the pressure of the pilot chamber. An annular concave portion (380) is formed on the outer circumferential side of the seal member (146), and an annular convex portion (385) is formed on the inner circumferential side of the seal member (146).