Movable Valve Body Tuning Damper Stroke Position

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Solution Overview

Problem

Existing damper assemblies for vehicle suspension struggle to tune damping forces effectively over the entire piston stroke, as the valve body's operation is primarily dependent on piston speed rather than position, leading to difficulties in achieving desirable damping characteristics and ensuring safe and durable piston movement at the end of its stroke.

Innovation Solution

The damper assembly features a valve body that moves into sealing engagement with a valve seat in response to a compressing spring, allowing damping fluid to flow exclusively through bores, providing additional damping force and making the operation dependent on the piston's position within the tube, thus enabling more precise tuning of damping characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a valve body is disposed in the first tube to control damping fluid flow, then damping force is provided over the entire piston stroke, but the valve body operation is dependent on piston speed rather than position, making it difficult to tune damping characteristics

Engineering Contradiction:
Improvedamping forceVSAvoidtuning of damping characteristics
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The valve body is made movable relative to the first tube, transitioning from a static component to a dynamic one that responds to piston position. The movable valve body is actuated by a spring mechanism that engages at specific stroke positions, allowing the damping characteristics to be dynamically adjusted based on piston position rather than just speed, thereby enabling more precise tuning of damping behavior throughout the stroke.

Inventive Principle:
Principle #15Dynamics

2Reliability

If jounce cushions are disposed at the ends of the first tube to slow or stop piston movement, then extreme movement is controlled, but the cushions are not ideal for safety and durability of the damper assembly

Engineering Contradiction:
Improvesafety and durabilityVSAvoidextreme movement of piston
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A spring mechanism is positioned within the first tube to provide beforehand cushioning for the movable valve body. This spring engages before the piston reaches extreme positions, gradually slowing and controlling the valve body's movement in advance, preventing abrupt impacts and enhancing the safety and durability of the damper assembly by avoiding hard stops at the ends of the stroke.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Adaptability or versatility

If the periphery of the valve body is spaced from the inner surface of the first tube to define an annular channel, then damping fluid can bypass the valve body, but the valve body must move into sealing engagement with the valve seat to provide additional damping force

Engineering Contradiction:
Improvedamping fluid flow pathsVSAvoidvalve body movement and sealing mechanism
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The valve body is designed to dynamically transition between two states: spaced from the valve seat to allow bypass flow through the annular channel, and moved into sealing engagement with the valve seat to restrict flow through bores for additional damping. This dynamic positioning, controlled by the spring mechanism responding to piston position, provides adaptable damping characteristics while maintaining a relatively simple structural implementation.

Inventive Principle:
Principle #15Dynamics

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 design allows for safer and more comfortable operation by ensuring proper energy dissipation at the end of the piston's stroke, enabling easier tuning of damping characteristics and enhancing the durability of the damper assembly.

Implementation Method 1

A spring is disposed within the first tube and engages and extends axially away from the valve body toward the upper portion of the first tube. A bumper is disposed in the first tube and engages the spring for compressing the spring as the bumper moves axially in the first tube toward the lower portion of the first tube.

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The valve body has a periphery and a top and a bottom and defines a plurality of bores extending axially through the valve body from the top to the bottom. The valve body moves into sealing engagement with the valve seat... which causes the damping fluid flowing through the annular channel to travel exclusively through the bores of the valve body which provides additional damping force.

Methodology Applied
Scientific EffectViscous damping: Viscous Damping

Data Source

PatentEP3207273B1Damper assembly
Publication Date: 2020.07.01 BEIJING WEST IND CO LTD
  • EP3207273B1 patent drawingFigure 1
  • EP3207273B1 patent drawingFigure 2
  • EP3207273B1 patent drawingFigure 3

AI summary

A damper assembly (20) is disclosed, and it comprises: a first rube (22) defining an inner surface (24) extending along an axis (A) to define a fluid chamber (30) containing a damping fluid (32); a rod (34) extending axially in the first rube (22); a guide (40) annularly disposed about the rod (34) and engaging the first tube (22); a piston (42) and a retainer (46) which are attached to the rod (34) and are slidably disposed in the first tube (22); a first spring (50) engaging and extending axially away from the retainer (46); a valve body (52) which is disposed adjacent to the first spring (50) and has a periphery (54) spaced from the inner surface (24) of the first tube (22) to define an annular channel (60); a second spring (66) extending axially away from the valve body (52); a bumper (68) engaging the second spring (66). The valve body (52) moves into sealing engagement with the retainer (46) in response to the bumper (68) engaging the guide (40). This causes the damping fluid (32) to move exclusively through the valve body (52) providing additional damping force.