Shock Absorber Sleeve Damping with Throttle Pressure Equalization

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Solution Overview

Problem

Existing hydraulic shock absorbers exhibit deviations in damping behavior under high loads and varying temperature conditions, leading to undesired pressure effects that distort the desired degressive damping behavior.

Innovation Solution

A shock absorber design with connecting channels and throttle valves between the jacket gap and cylinder interior, allowing controlled pressure equalization and adjusting the pressure ratio, using a Tesla valve structure to manage fluid flow in both compression and rebound stages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a damper sleeve is used to expand under pressure to increase the annular gap, then the shock absorber becomes almost purely displacement-dependent, but deviations from desired damping behavior occur under high loads and varying temperature conditions

Engineering Contradiction:
Improvedisplacement-dependent dampingVSAvoiddamping behavior consistency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

A connecting channel is introduced as an intermediary element between the cylinder interior and the jacket gap. This channel includes a throttle valve that mediates fluid flow, allowing controlled pressure equalization while maintaining the damper sleeve's expansion capability. The throttle valve restricts flow in one direction (from cylinder interior to jacket gap) while allowing freer flow in the opposite direction, thus managing pressure imbalances under high loads.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the flow resistance parameter dynamically through the throttle valve in the connecting channel. By restricting fluid flow from the cylinder interior to the jacket gap, the system adjusts pressure distribution in response to varying loads and temperature conditions, maintaining consistent damping behavior across different operating parameters.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If the annular gap is increased to facilitate fluid flow, then the shock absorber loses velocity dependence, but overpressure in the sleeve gap causes unintended increase in damping force

Engineering Contradiction:
Improvefluid flow capabilityVSAvoidoverpressure effects
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The connecting channel with throttle valve serves as a mediator between the cylinder interior and jacket gap. It controls pressure equalization by restricting flow in the direction from cylinder interior to jacket gap, preventing overpressure buildup in the sleeve gap while maintaining adequate fluid flow capability through the annular gap.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention replaces purely mechanical pressure balancing (through sleeve expansion alone) with a controlled fluid dynamic system. The throttle valve creates a pressure drop across the connecting channel, substituting uncontrolled elastic expansion with controlled hydraulic flow management to eliminate overpressure effects.

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

3Stress or pressure

If a compensating bore is added to balance pressure in the sleeve gap, then pressure balance is achieved, but the bore becomes overloaded under high power demands and cannot adequately discharge combined oil volume

Engineering Contradiction:
Improvepressure balanceVSAvoidfluid discharge capability
Core Design Contradiction:
Stress or pressureVSProductivity

Solution Approach 1:

The connecting channel with throttle valve acts as an intermediary pressure management system. Instead of relying on a single compensating bore that becomes overloaded, the throttle valve provides continuous pressure regulation by controlling fluid flow between the cylinder interior and jacket gap, maintaining pressure balance without discharge bottlenecks.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention extracts the pressure balancing function from the compensating bore system and relocates it to the connecting channel with throttle valve. This separates the pressure regulation function from the fluid discharge function, allowing the compensating bore to handle only local pressure equalization while the throttle valve manages overall pressure balance and fluid flow.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Ensures a defined damping characteristic even under high workloads and changing conditions, maintaining the desired degressive damping behavior by managing pressure imbalances through controlled fluid flow.

Implementation Method 1

a connecting channel (57) which connects the jacket gap (12) to the cylinder interior (13) and in which a throttle valve is arranged, wherein the throttle valve is designed such that fluid flow is restricted only in the direction from the cylinder interior (13) into the jacket gap (12)

Methodology Applied
Scientific EffectThrottle valve flow restriction: Valve

Implementation Method 2

using a Tesla valve structure to manage fluid flow in both compression and rebound stages

Methodology Applied
Scientific EffectTesla valve: Tesla Valvular Conduit

Implementation Method 3

the outer diameter of which is smaller than the inner diameter of the cylinder tube. This allows the damper sleeve to expand when the pressure in the cylinder increases, thereby increasing the annular gap between the damper sleeve and the piston

Methodology Applied
Scientific EffectElastic expansion: Elasticity

Implementation Method 4

Within the shock absorber, hydraulic oil is forced through narrow bores and valve systems via a piston. The damping force, which counteracts the damper's velocity, increases with the piston's compression or rebound velocity

Methodology Applied
Scientific EffectHydraulic damping: Hydraulic Press

Data Source

PatentEP4675125A1Shock absorber
Publication Date: 2026.01.07 DRIVEMAN GMBH
  • EP4675125A1 patent drawingFigure 1a~1b
  • EP4675125A1 patent drawingFigure 2a~3
  • EP4675125A1 patent drawingFigure 4

AI summary

The invention relates to a shock absorber comprising a cylinder (1) filled with a fluid and a piston rod (3) guided therein, wherein the piston rod (3) is guided into or through the cylinder (1) and is provided with at least one piston (4), wherein at least one damper sleeve (2) is arranged in the cylinder (1) surrounding the at least one piston (4), the outer diameter of which is smaller than the inner diameter of the cylinder (1) and the inner diameter of which is larger than the outer diameter of the at least one piston (4), whereby an annular gap (43) is formed between the at least one piston (4) and the at least one damper sleeve (2), and a shell gap (12) is formed between the at least one damper sleeve (2) and the cylinder (1), characterized in that the shell gap (12) is connected to the cylinder interior on at least one side via at least one connecting channel (57).wherein a throttle valve is arranged in the connecting channel (57).