Vehicle Brake System Draining Circuit Design

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Solution Overview

Problem

In vehicle brake systems with shared brake disc assemblies for service and parking brakes, existing anti-compounding solutions complicate the design by requiring adaptation of effective piston areas, leading to potential overload and damage due to combined forces.

Innovation Solution

A draining circuit that diverts service brake pressure to a return tank when the parking brake is engaged, using a non-return valve to prevent flow from the parking brake circuit to the service brake circuit, thereby avoiding overload without adapting piston areas and simplifying the design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If service brake and parking brake functions share brake assemblies, then space utilization is improved, but brake assembly overload risk increases

Engineering Contradiction:
Improvespace utilizationVSAvoidbrake assembly overload
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

A draining circuit acts as an intermediary between the service brake circuit and parking brake circuit. When the parking brake is engaged, the draining circuit diverts service brake pressure to a return tank, preventing the叠加 of forces on the brake disc assembly. This mediator mechanism allows both brake functions to share the same brake assembly without causing overload.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If anti-compounding solution with double check valve assembly is used, then brake assembly overload is prevented, but device complexity increases

Engineering Contradiction:
Improvebrake assembly overloadVSAvoiddevice complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention extracts the draining function from the brake assembly design itself and implements it through a separate draining circuit. Instead of adapting piston areas within the brake assembly (which would complicate the assembly design), the solution takes out the pressure management function to a dedicated circuit with a non-return valve and return tank, simplifying the brake assembly while preventing overload.

Inventive Principle:
Principle #2Taking out (Extraction)

3Force

If service brake pressure is allowed to act on engaged parking brake, then braking force is improved, but brake disc friction material damage occurs

Engineering Contradiction:
Improvebraking forceVSAvoidfriction material integrity
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The draining circuit implements preliminary anti-action by preemptively diverting service brake pressure away from the brake disc assembly when the parking brake is engaged. The non-return valve detects parking brake engagement and automatically routes service brake pressure to the return tank before it can combine with parking brake force, thereby protecting the friction material from overload damage while maintaining the ability to apply service brakes independently.

Inventive Principle:
Principle #9Preliminary anti-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

This solution prevents brake disc assembly overload, provides flexibility in brake system design, and ensures reliable operation independent of electric valves or software control, even in power or control system failures.

Implementation Method 1

A draining circuit is provided in the vehicle brake system that is adapted to drain the service brake circuit when the parking brake circuit is drained, with a non-return valve to prevent flow from the parking brake circuit to the service brake circuit

Methodology Applied
Scientific EffectValve: Valve

Data Source

PatentEP3322621B1A vehicle brake system
Publication Date: 2020.03.25 VOLVO CONSTRUCTION EQUIPMENT AB
  • EP3322621B1 patent drawingFigure 1~2
  • EP3322621B1 patent drawingFigure 3
  • EP3322621B1 patent drawingFigure 4~5

AI summary

The invention provides a vehicle brake system (16) comprising - a brake assembly providing a service brake (1611) and a parking brake (1612) having a brake disc assembly in common, - a service brake circuit (163), - a parking brake circuit (164), and - a brake control arrangement (165, 1671, 1672, 1673, 1682) adapted to control the service brake (1611) by selectively providing a fluid communication between a pressurising arrangement (166) and the service brake (1611) via the service brake circuit (163), the brake control arrangement (165, 1671, 1672, 1673, 1682) further being adapted to control the parking brake (1612) by selectively providing a fluid communication between the pressurising arrangement (166) and the parking brake (1612) via the parking brake circuit (164), and by selectively draining the parking brake circuit (164), - wherein the vehicle brake system comprises a draining circuit (168) adapted to drain the service brake circuit (163) to avoid overload of the brake disc assembly.