Linkage Assembly Elastomeric Damping for Brake Pushrod Wear

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Solution Overview

Problem

Hydraulically powered brake systems in off-highway vehicles experience wear and vibration issues due to the interaction between pushrods and plungers, leading to noise and reduced force transmission, and existing solutions like extension springs add complexity and resistance.

Innovation Solution

A linkage assembly featuring a pushrod coupled with a resilient elastomeric member that deforms to allow direct engagement with the plunger, providing vibration damping and reducing wear by using a rubber or elastomeric element to isolate the pushrod from the plunger during normal operations and compressing to enable direct contact during braking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a guide bushing is used to keep the pushrod in vertical orientation, then the pushrod maintains proper alignment, but the pushrod slides over the plunger surface causing wear

Engineering Contradiction:
Improvepushrod alignmentVSAvoidcomponent wear
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

A resilient member is introduced as an intermediary between the pushrod and plunger. This resilient member deforms to accommodate the pushrod's arc motion while maintaining contact with the plunger, eliminating direct sliding contact and wear between the pushrod and plunger surfaces.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The resilient member changes its deformation parameters to adapt to the pushrod's motion. It deforms elastically to allow the pushrod to swing along an arc while maintaining engagement with the plunger, thus accommodating the motion without causing wear.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If an extension spring is added to hold the pushrod off the plunger, then vibration is reduced, but additional components and resistance are added to the system

Engineering Contradiction:
Improvevibration transmissionVSAvoidnumber of components
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The resilient member combines multiple functions into a single component: it acts as a vibration isolator, a motion accommodation element, and a force transmission medium. This eliminates the need for separate extension springs, upstops, and mounting brackets required in previous designs.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The resilient member serves multiple purposes simultaneously: it dampens vibrations, accommodates the pushrod's arc motion, and transmits braking force. This multi-functional design simplifies the overall system by replacing multiple specialized components with one universal element.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Force

If the pushrod directly engages the plunger, then force transmission is efficient, but vibration and noise are transmitted to the brake pedals

Engineering Contradiction:
Improveforce transmissionVSAvoidvibration and noise
Core Design Contradiction:
ForceVSObject-generated harmful factors

Solution Approach 1:

The resilient member serves as a mediator between the pushrod and plunger. It transmits the braking force from the pushrod to the plunger while simultaneously absorbing and isolating vibrations and noises, preventing them from transmitting to the brake pedals and operator.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The resilient member converts the harmful vibrations and noises into elastic deformation energy. By deforming under the impact and vibration, it absorbs these harmful energies and dissipates them, transforming the harmful effects into a beneficial damping action.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 effectively reduces wear and vibration transmission, maintaining force transmission efficiency while minimizing added resistance, thus enhancing the braking performance and operator experience.

Implementation Method 1

The resilient member deforms to allow the pushrod to directly engage the plunger when the pushrod is moved towards the plunger

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

The resilient member deforms to allow the pushrod to directly engage the plunger when the pushrod is moved towards the plunger

Methodology Applied
Scientific EffectVibration damping: Damping

Data Source

PatentEP3028911B1Linkage assembly for coupling a plunger of an actuator to a manually operated input member
Publication Date: 2018.08.01 DEERE & CO
  • EP3028911B1 patent drawingFigure 1
  • EP3028911B1 patent drawingFigure 2
  • EP3028911B1 patent drawingFigure 3

AI summary

A linkage assembly (10) for coupling a plunger (12) of an actuator (14) to a manually operated input member (16) is provided. The linkage assembly (10) comprises a pushrod (18) and a resilient member (20) coupled to the pushrod (18). The resilient member (20) has an outer end (27) which is engagable with the plunger (14) when the pushrod (18) is spaced apart from the plunger (14). The resilient member (20) deforms to allow the pushrod (18) to directly engage the plunger (14) when the pushrod (18) is moved towards the plunger (14).