Valve Assembly Vibration Damping Hydraulic Drive

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Solution Overview

Problem

Conventional hydraulic clutch control systems experience vibration transmission from the internal combustion engine to the clutch pedal due to the lack of effective vibration decoupling between the master and slave cylinders, leading to undesirable pedal vibrations and increased force required for actuation, especially at low temperatures.

Innovation Solution

A valve arrangement with two spring-loaded valve bodies and a volume sensor that opens immediately with fluid flow in either direction, reducing residual pressure and friction losses, and effectively isolates the liquid column sections to prevent vibration transmission, featuring a compact design with minimal resistance and reduced friction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a valve arrangement is used to isolate vibrations between master and slave cylinders, then vibration transmission is reduced, but the force required to actuate the clutch pedal increases

Engineering Contradiction:
Improvevibration transmissionVSAvoidactuation force
Core Design Contradiction:
Object-affected harmful factorsVSForce

Solution Approach 1:

The valve arrangement is segmented into two separate valve bodies (first and second valve bodies) that can independently open and close. This segmentation allows the system to isolate vibrations effectively while maintaining low actuation force, as each valve body can respond independently to pressure changes without requiring excessive force to operate the entire system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The valve arrangement employs spring elements that provide dynamic response to pressure changes. The springs allow the valve bodies to open and close automatically based on the instantaneous pressure conditions, creating a dynamic system that adapts to varying operating conditions without requiring high actuation force from the driver.

Inventive Principle:
Principle #15Dynamics

2Object-affected harmful factors

If longer pipelines are used to increase damping, then vibration transmission is reduced, but the return speed of the clutch pedal decreases

Engineering Contradiction:
Improvevibration transmissionVSAvoidpedal return speed
Core Design Contradiction:
Object-affected harmful factorsVSSpeed

Solution Approach 1:

The valve arrangement acts as an intermediary device placed between the master and slave cylinders. It provides vibration isolation without requiring long pipeline lengths, thereby maintaining fast pedal return speed while still effectively reducing vibration transmission through its active valve mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If orifices or throttles are installed to increase flow resistance, then vibration damping improves, but the force required for quick clutch actuation increases

Engineering Contradiction:
Improvevibration dampingVSAvoidactuation force
Core Design Contradiction:
Object-affected harmful factorsVSForce

Solution Approach 1:

The valve arrangement provides dynamic flow control through spring-loaded valve bodies that open and close based on pressure conditions. This dynamic mechanism achieves vibration damping without the continuous flow resistance of fixed orifices or throttles, allowing quick actuation with minimal force when the valves are open.

Inventive Principle:
Principle #15Dynamics

4Object-affected harmful factors

If a preloaded valve arrangement is used to block vibrations, then vibration isolation improves, but residual pressure builds up delaying valve body return

Engineering Contradiction:
Improvevibration isolationVSAvoidvalve body return time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The segmented valve design with two independent valve bodies allows one valve to close while the other remains open, providing alternative flow paths. This prevents residual pressure buildup that would delay valve return, as the segmented structure enables pressure equalization through different routes during the valve operation cycle.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The valve arrangement allows partial flow through alternative paths (the second valve body) while the primary path is closed for vibration isolation. This partial action prevents complete pressure buildup by maintaining some flow capability, thereby reducing the time required for valve body return.

Inventive Principle:
Principle #16Partial or excessive action

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 significantly reduces vibration transmission from the slave cylinder to the master cylinder, improving the return speed of the clutch pedal and maintaining effective vibration isolation across varying temperatures and pressures, while minimizing the force required for actuation.

Implementation Method 1

The first valve body is prestressed by a first spring element in a first direction against a stop fixed to the housing

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

The second valve body is prestressed by a second spring element in a second direction opposite to the first direction against a valve seat on the first valve body

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 3

a volume sensor mounted in a bore of the housing adjacent one of the first and second valve bodies, which volume sensor is elastically deformable under pressure in order to reduce residual vibrations

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP1719921B1Valve assembly for dampening vibrations in a hydraulic drive comprising a master cylinder and a slave cylinder
Publication Date: 2011.08.03 FTE AUTOMOTIVE GMBH & CO KG
  • EP1719921B1 patent drawingFigure 1~20
  • EP1719921B1 patent drawingFigure 2~9
  • EP1719921B1 patent drawingFigure 4~7

AI summary

The valve device has two through passages (60, 66) for hydraulic fluid. The second of these is between the first valve body (52) and a housing. There is a valve seat (68) on the stop (58) fixed to the housing, against which the first valve body is pre-stressed, so that in the basic position of the valve unit, the first valve body completely or almost completely closes the second through passage.