Vehicle Brake Device Bypass Passage Reduces Flow Resistance

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Solution Overview

Problem

Conventional brake devices face difficulties in smoothly suctioning and pressurizing brake fluid from the reservoir to the wheel cylinders due to high flow resistance at the master cut valve, leading to inefficient braking performance.

Innovation Solution

Incorporating a shut-off valve that switches between closed and open states based on brake pedal operation and a bypass passage with a one-way valve to reduce flow resistance, allowing the pump to suction fluid efficiently from the reservoir and supply pressurized fluid to the wheel cylinders.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the master cut valve is kept open to allow brake fluid flow, then the brake fluid can reach the wheel cylinders, but the flow resistance becomes large making it difficult for the pump to suction fluid smoothly

Engineering Contradiction:
Improvebrake fluid supply reliabilityVSAvoidfluid suction efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent divides the single fluid path into two separate paths: a main passage through the master cut valve and a bypass passage with a one-way valve. This segmentation allows the system to utilize both paths simultaneously, with the bypass passage providing a low-resistance route for the pump to suction brake fluid while the main passage maintains reliable fluid supply to the wheel cylinders.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The one-way valve acts as an intermediary element that selectively allows fluid flow from the reservoir to the pump through the bypass passage while preventing reverse flow. This intermediary component enables the pump to efficiently suction brake fluid without being hindered by the high flow resistance of the master cut valve, thus resolving the contradiction between supply reliability and suction efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If the pump suctions brake fluid through the master cut valve, then the fluid can be pressurized and supplied to wheel cylinders, but the high flow resistance at the valve part hinders smooth suction

Engineering Contradiction:
Improvebrake fluid pressurization capabilityVSAvoidfluid suction smoothness
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

The patent segments the fluid suction path from the pressurization and distribution path. The bypass passage with the one-way valve is dedicated to smooth fluid suction by the pump, while the main passage through the master cut valve handles pressurization and distribution to the wheel cylinders. This segmentation eliminates the conflict between suction smoothness and pressurization capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses partial action by having the pump suction brake fluid through only the bypass passage with the one-way valve, rather than attempting to suction through the high-resistance master cut valve. This partial path utilization ensures smooth suction while the main passage continues to provide the necessary pressurization capability.

Inventive Principle:
Principle #16Partial or excessive 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 configuration enables the pump to smoothly suction and pressurize brake fluid, ensuring quick and reliable application of braking forces to the vehicle wheels, even when the master cut valve is in an open state, thereby stabilizing vehicle behavior.

Implementation Method 1

a bypass passage is provided in communication with the reservoir from the fluid pressure control valve mechanism bypassing the shut-off valve and includes a one-way valve for permitting only a flow in one direction from the side of the reservoir to the side of the fluid pressure control valve mechanism

Methodology Applied
Scientific EffectOne-way valve flow control: Valve

Implementation Method 2

the pump provided in the fluid pressure control valve mechanism can suction the operation fluid smoothly from the reservoir provided at the side of the master cylinder and pressurize the suctioned operation fluid to supply the pressurized operation fluid quickly to the wheel cylinders

Methodology Applied
Scientific EffectPump pressurization: Pump

Data Source

PatentEP2995516B1Vehicle brake device
Publication Date: 2017.10.11 TOYOTA JIDOSHA KK
  • EP2995516B1 patent drawingFigure 1
  • EP2995516B1 patent drawingFigure 2
  • EP2995516B1 patent drawingFigure 3

AI summary

A master cylinder 21 includes pressurizing chambers 21a1, 21b1 and atmospheric pressure chambers 21a2, 21b2 which are in communication with a reservoir 22 provided upstream. The pressurizing chambers 21a1, 21b1 of the master cylinder 21 are connected to a brake fluid pressure control valve device 50 through master pressure pipes 11, 12 provided with master cut valves 23, 24, respectively. The atmospheric pressure chambers 21 a2, 21 b2 of the master cylinder 21 bypass the master cut valves 23, 24 and are connected to the brake fluid pressure control valve device 50 through bypass pipes 13, 14 provided with a check valves 25, 26, respectively. A pump 55a, 55b constituting a brake fluid pressurizing section 55 of the brake hydraulic control valve device 50 suctions the brake fluid from the reservoir 22 preferentially through the bypass pipes 13, 14 provided with the check valves 25, 26 and pressurizes the brake fluid to supply a brake fluid pressure to brake fluid pressure adjust sections 51 to 54, respectively.