Overflow Valve Dual Spring Segmentation Hysteresis

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing overflow valves for compressed air devices require high spring forces and exhibit significant hysteresis and unfavorable construction volume, leading to inefficient and difficult-to-adjust switching behavior.

Innovation Solution

The overflow valve design features a second compression spring supported in the upper housing part, axially spaced from the valve seat, which reduces tilting and friction, allowing for smaller spring forces and improved sealing, with a first compression spring for fine adjustments and a membrane to isolate pressure effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a conventional overflow valve design with a single compression spring is used, then the valve can maintain sealing contact, but high spring forces are required and significant hysteresis occurs

Engineering Contradiction:
Improvespring forceVSAvoidswitching behavior
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The single compression spring is divided into two separate compression springs: a first compression spring (10) that acts in the opening direction and a second compression spring (20) that acts in the closing direction. This segmentation allows each spring to be optimized for its specific function, enabling the use of smaller spring forces while reducing hysteresis and improving switching behavior reliability.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the compression spring is positioned close to the valve seat, then sealing contact is maintained, but the switching piston tilts and friction increases

Engineering Contradiction:
Improvesealing contactVSAvoidfriction
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The second compression spring (20) is positioned at a distance from the valve seat in the axial dimension, rather than directly adjacent to it. This spatial repositioning allows the spring to act on the switching piston without causing tilting, reducing friction while maintaining sealing contact through the distributed force application.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If the spring force is increased to maintain sealing, then the valve remains sealed, but hysteresis and construction volume increase

Engineering Contradiction:
ImprovesealingVSAvoidconstruction volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

By segmenting the spring system into two directional springs, each spring can be smaller and more efficient, reducing the overall construction volume while maintaining reliable sealing. The distributed force application eliminates the need for oversized springs.

Inventive Principle:
Principle #1Segmentation

4Ease of operation

If the overflow valve uses a conventional single-spring design, then the structure is simple, but switching behavior is difficult to adjust and hysteresis is high

Engineering Contradiction:
Improveswitching behavior adjustmentVSAvoidhysteresis
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The system allows dynamic adjustment of the first compression spring (10) to fine-tune the switching pressure point, while the second compression spring (20) provides a stable closing force. This dynamic adjustability optimizes switching behavior and minimizes hysteresis.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

By independently adjusting the parameters of two separate springs (force constants, preloads), the switching characteristics can be precisely controlled to minimize hysteresis and optimize performance.

Inventive Principle:
Principle #35Parameter changes

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 achieves lower hysteresis and better, easily adjustable switching behavior with reduced spring forces, minimizing tilting and leaks, and optimizing sealing pressure.

Implementation Method 1

a first compression spring (10) which acts in the opening direction of the overflow valve on the switching piston (31) with an adjustable restoring force

Methodology Applied
Scientific EffectCompression spring restoring force: Spring

Implementation Method 2

a second compression spring (20) is also present, which acts in the closing direction of the overflow valve on the switching piston (31) with a predetermined restoring force

Methodology Applied
Scientific EffectCompression spring restoring force: Spring

Implementation Method 3

a membrane to isolate pressure effects

Methodology Applied
Scientific EffectPressure isolation: Semipermeable Membrane

Implementation Method 4

a switching piston (31) which, in a closed position of the overflow valve (1), sits sealingly on a valve seat (30)

Methodology Applied
Scientific EffectSealing contact: Friction

Data Source

PatentEP3453581B1Overflow valve and compressed air device for motor vehicles
Publication Date: 2020.03.11 ZF CV SYST HANNOVER GMBH
  • EP3453581B1 patent drawingFigure 1

AI summary

The invention relates to a pressure relief valve (1) for compressed air systems, which has a pressure inlet (4) and a pressure outlet (6) for compressed air, and with a switching piston (31) which, in a closed position of the pressure relief valve (1), seals against a valve seat (30) and which can be lifted from the valve seat (30) against an adjustable restoring force of a compression spring (9) under the influence of the compressed air pressure present at the pressure inlet (4) of the pressure relief valve (1). The invention was based on the objective of proposing a pressure relief valve whose opening characteristic is not influenced by the controlled pressure, requires smaller spring forces, and exhibits smaller hysteresis as well as easily adjustable switching behavior at smaller spring forces.This problem is solved by the additional provision of a second compression spring (39) which acts on the switching piston (31) with a predefinable restoring force in the closing direction of the overflow valve (1).