Hydraulic Brake Assembly Third Conduit Bypass

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing hydraulic brake assemblies face challenges in reducing dead running of vehicles when braking, particularly due to increased spacing between brake linings and friction surfaces, which delays braking and does not align with ecological constraints to reduce carbon emissions, and requires significant modifications to the booster.

Innovation Solution

A hydraulic braking assembly with a third conduit that bypasses pressure to directly fill the primary chamber, increasing pressure inside the master cylinder and hydraulic braking circuit, controlled by sensors and hydraulic pumps to reduce dead stroke without major booster modifications, and utilizing a computer to manage fluid supply and pressure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If the brake lining is separated from the friction surface to reduce carbon emissions, then ecological constraints are satisfied, but the dead running time increases and braking is delayed

Engineering Contradiction:
Improvecarbon emissionsVSAvoiddead running time
Core Design Contradiction:
Object-generated harmful factorsVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pressurizing the primary chamber before the thrust chamber during brake pedal depression. This pre-pressurization of the primary chamber (via the bypass conduit) ensures that when the thrust chamber fills and the feeler piston moves, the brake linings engage the friction surfaces immediately without delay, thus reducing dead running time while maintaining the separated rest position for ecological benefits

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a bypass conduit as an intermediary pathway that allows hydraulic fluid to reach the primary chamber directly, bypassing the thrust chamber. This intermediary route enables independent pressurization of the primary chamber, decoupling the timing of primary chamber pressurization from thrust chamber filling, thereby eliminating dead running delay while preserving the ecological advantage of separated brake linings

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the brake pedal is depressed deeply to take up all play before braking, then complete contact is achieved, but the driver must depress the pedal for too long a distance

Engineering Contradiction:
Improvebrake contact reliabilityVSAvoidbrake pedal stroke distance
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system performs preliminary action by automatically pressurizing the primary chamber through the bypass conduit as soon as the brake pedal is depressed, before the thrust chamber fills. This pre-pressurization eliminates the need for deep pedal depression to take up play, as the brake linings are already positioned near the friction surfaces by the pre-applied hydraulic pressure

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The bypass conduit acts as an intermediary that provides a direct hydraulic pathway to the primary chamber, independent of the thrust chamber filling process. This intermediary mechanism delivers hydraulic pressure to the brake linings immediately upon pedal depression, eliminating the long stroke distance requirement while ensuring reliable brake contact

Inventive Principle:
Principle #24Intermediary (Mediator)

3Loss of time

If the thrust chamber volume is increased to reduce dead stroke, then dead running is reduced, but significant modifications to the booster are required

Engineering Contradiction:
Improvedead stroke durationVSAvoidbooster modification complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The patent applies segmentation by separating the hydraulic fluid supply paths into two independent routes: the original path through the thrust chamber and a new bypass path directly to the primary chamber. This segmentation allows the system to achieve rapid brake lining engagement through the bypass without modifying the thrust chamber volume, thus reducing dead stroke without complex booster modifications

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bypass conduit serves as an intermediary pathway that provides an alternative route for hydraulic fluid to reach the primary chamber. This intermediary structure enables the system to reduce dead stroke duration by pre-pressurizing the primary chamber without requiring modifications to the thrust chamber or booster geometry, avoiding complex modifications

Inventive Principle:
Principle #24Intermediary (Mediator)

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 reduces the duration of dead stroke, ensures immediate brake lining engagement, and maintains ecological constraints by minimizing carbon emissions without degrading performance in assist failure modes.

Implementation Method 1

A hydraulic pump is connected to the third conduit, the fluid filling in the primary chamber via the third conduit being controlled by a sensor which activates the pump when the brake pedal is pressed

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

The primary chamber is supplied with hydraulic fluid by a first reservoir of hydraulic fluid via a first conduit. This first duct is formed through a body of the master cylinder.

Methodology Applied
Scientific EffectHydraulic fluid transmission: Hydraulic Press

Implementation Method 3

There is then an overpressure in the primary chamber and also in the ducts of the hydraulic braking circuit. This causes the brake linings to move closer to their friction surface, resulting in braking

Methodology Applied
Scientific EffectHydraulic force transmission: Pascal's Law

Implementation Method 4

The feeler piston is then driven in the direction of the master cylinder due to the movement of the control rod but also due to the pressure exerted by the fluid injected into the thrust chamber on the feeler piston

Methodology Applied
Scientific EffectHydraulic pressure force: Pressure Increase

Data Source

PatentEP2646300B1Hydraulic assembly for braking a vehicle and reducing the free travel of said vehicle
Publication Date: 2017.04.26 ROBERT BOSCH GMBH
  • EP2646300B1 patent drawingFigure 1
  • EP2646300B1 patent drawingFigure 2
  • EP2646300B1 patent drawingFigure 3

AI summary

The invention relates to a hydraulic brake assembly (1) comprising a braking-assistance servomotor (2), a master cylinder (3), a first hydraulic-fluid tank (19) supplying hydraulic fluid to a primary chamber (16) of the master cylinder, and a second hydraulic-fluid tank (24) supplying hydraulic fluid to a thrust chamber of the servomotor. According to the invention, the assembly includes a third pipe (26) leading from the second tank into the primary chamber of the master cylinder. The filling of the primary chamber with fluid is controlled via the second tank and via the third pipe at the instant the brake pedal is depressed and prior to the filling of the thrust chamber.