Brake Control Device Stroke Simulator Hydraulic Pressure Response

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Solution Overview

Problem

Conventional brake control systems require larger or more expensive actuators to improve pressure response in wheel cylinders, which is inefficient and costly.

Innovation Solution

The brake control system uses a stroke simulator that operates in response to the driver's brake operation to generate hydraulic pressure, independent of the actuator size, by flowing brake fluid from a master cylinder to wheel cylinders, enhancing pressure response without the need for a larger actuator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a larger or more expensive actuator is used for the hydraulic pressure source, then the pressure response in wheel cylinders is improved, but the device complexity and cost increase

Engineering Contradiction:
Improvepressure responseVSAvoidactuator size
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The brake control system divides the hydraulic pressure generation into two independent sources: the master cylinder handles normal braking pressure generation, while a separate auxiliary hydraulic pressure source provides additional pressure when needed. This segmentation allows each component to be optimized for its specific function, avoiding the need for a single large actuator to handle all pressure requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The auxiliary hydraulic pressure source is designed to work in conjunction with the master cylinder, serving multiple functions: it can supplement master cylinder pressure when braking force is insufficient, maintain pressure when the master cylinder pressure drops, and operate independently if needed. This multi-functionality allows the system to achieve high pressure response without requiring the main actuator to be oversized.

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

2Productivity

If a larger actuator is used to improve pressure response, then the wheel cylinder pressure demand is met faster, but the cost and system complexity increase

Engineering Contradiction:
Improvepressure generation speedVSAvoidsystem cost
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The system segments the pressure generation task between the master cylinder (handling routine braking) and the auxiliary hydraulic pressure source (handling peak or emergency pressure demands). This allows the auxiliary source to be a smaller, more cost-effective component rather than requiring a large expensive actuator to handle all scenarios.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The auxiliary hydraulic pressure source is designed to automatically activate when the master cylinder pressure is insufficient, without requiring complex control systems or large actuators. The system self-regulates by utilizing the auxiliary source only when needed, reducing overall system cost while maintaining high productivity when pressure is demanded.

Inventive Principle:
Principle #25Self-service

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 approach improves the response to increased wheel cylinder pressure demands while maintaining a minimal actuator size, reducing costs and enhancing system efficiency.

Implementation Method 1

a spring (221) that is compressed and thereby generates an elastic force acting on the piston (220) in the first direction

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

brake control systems that comprise a stroke simulator for generating force reacting to a driver's braking operation and use a hydraulic pressure source separate from a master cylinder to generate hydraulic pressure that is applied to the wheel cylinders

Methodology Applied
Scientific EffectHydraulic pressure transmission: Pascal's Law

Data Source

PatentEP3135549B1Brake control device, braking system, and brake hydraulic pressure generation method
Publication Date: 2020.09.23 HITACHI AUTOMOTIVE SYST LTD
  • EP3135549B1 patent drawingFigure 1
  • EP3135549B1 patent drawingFigure 2~3
  • EP3135549B1 patent drawingFigure 4

AI summary

A system comprises: pump 7 (hydraulic pressure source) that uses brake fluid supplied from reservoir tank 4 (reservoir) to generate hydraulic pressure in first hydraulic line 11, thereby generating hydraulic pressure in wheel cylinder 8; piston 220 configured to move axially in cylinder 22a under the action of hydraulic fluid supplied from master cylinder 5, piston 220 dividing cylinder 22a into at least two chambers (positive pressure chamber R1 and backpressure chamber R2); stroke simulator 22 for generating reaction force to a driver's brake operation by moving piston 220; second hydraulic line 12 provided between positive pressure chamber R1 (one chamber) in stroke simulator 22 and master cylinder 5; and third hydraulic chamber 13 provided between backpressure chamber R2 (other chamber) and first hydraulic chamber 11 to transmit brake fluid from backpressure chamber R2 to first hydraulic chamber 11.