Spring Steel Coupling Element for Engine Brake Actuation

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Solution Overview

Problem

The existing connecting device for an actuating lever to a control valve in engine brakes is not robust, durable, or cost-effective, requiring improvements in design and materials to enhance performance and longevity.

Innovation Solution

A resilient coupling element made of spring steel with parallel limbs and a C- or Z-shaped configuration, where the first limb is pivotably mounted in the control slide's bore and the second limb is latched into the actuating lever's locking groove, ensuring a secure, play-free connection without additional securing means, allowing for easy assembly and high durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a U-shaped sheet metal coupling element with slots is used to connect the actuating lever to the control slide, then the connection can be established, but the device lacks robustness and durability

Engineering Contradiction:
Improveconnection durabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The coupling element is changed from U-shaped sheet metal with slots to a wire with round cross-section. This parameter change in geometry and material form provides inherent flexibility and robustness while simplifying the manufacturing process to basic wire forming and bending operations.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Instead of using a rigid U-shaped structure with slots that requires complex assembly, the invention uses a flexible wire that is bent into shape. The wire is inserted through the control slide bore and then bent to engage the actuating lever, inverting the approach from rigid-with-clearances to flexible-with-form-fit.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If additional securing means are used to fasten the coupling element, then the connection becomes more secure, but the assembly process becomes more complex and time-consuming

Engineering Contradiction:
Improveconnection securityVSAvoidassembly speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The coupling element is designed to be self-securing through its bent wire configuration. The wire engages the actuating lever through elastic deformation and geometric interlocking, eliminating the need for separate fasteners, clips, or securing mechanisms. The assembly is complete simply by inserting and bending the wire into its final position.

Inventive Principle:
Principle #25Self-service

3Strength

If the coupling element is made from rigid material, then it can withstand actuating forces, but it cannot accommodate pivoting movements and may cause wear or failure

Engineering Contradiction:
Improveforce withstanding capacityVSAvoidpivoting accommodation
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The coupling element uses a flexible wire configuration that can bend and pivot to accommodate the movement between the control slide and actuating lever. The wire's flexibility allows it to follow the pivoting motion while maintaining sufficient stiffness to transmit the required actuating forces, combining adaptability with strength.

Inventive Principle:
Principle #30Flexible shells and thin films

4Reliability

If deep locking grooves are formed in the actuating lever to secure the coupling element, then the connection becomes more secure, but the actuating lever is weakened and has reduced service life

Engineering Contradiction:
Improveconnection securityVSAvoidactuating lever service life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The engagement method is changed from deep grooves to a shallow locking groove combined with elastic deformation of the wire. The wire's flexibility provides the securing force through its bent configuration rather than relying on deep mechanical interlocking, thereby preserving the actuating lever's structural integrity and extending its service life.

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

The solution provides a robust, durable, and cost-effective connection that withstands actuating forces, ensuring a long service life with minimal deformation and no weakening of the components, facilitating easy installation and operation of the engine brake system.

Implementation Method 1

the coupling element consists of spring steel

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3549834B1Engine brake for an internal combustion vehicle
Publication Date: 2022.07.27 ZF CV SYST EURO BV
  • EP3549834B1 patent drawingFigure 1~4

AI summary

The invention relates to a device for connecting an actuating lever (1) to a control slide (8) of a control valve (7), in which the actuating lever (1) is designed as a pivoting lever and is connected to the control slide (8) by means of a spring-elastic coupling element (11). To make this device robust and cost-effective, the invention provides that the coupling element (11) has two legs (12, 13) aligned parallel to each other and a section (15) connecting the two legs (12, 13), and that the first leg (12) of the coupling element (11) is pivotably mounted on the free end (9) of the control slide (8), and that the second leg (13) can be locked to the free end (3) of the actuating lever (1).