Hydraulic Block Guide Section for Lubricated Brake Piston Travel

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Solution Overview

Problem

Current hydraulic blocks for external power vehicle brake systems face challenges in efficiently generating and controlling brake pressure, particularly in slip-controlled systems like ABS, ASR, and ESP, where mechanical and hydraulic interconnection of components is complex and requires effective lubrication and sealing to prevent jamming and ensure reliable brake actuation.

Innovation Solution

The hydraulic block incorporates an external power cylinder bore with a guide section and piston seals, featuring a brake fluid channel for lubrication and a radially guiding design that allows axially displaceable movement of the external power piston, ensuring smooth operation and preventing jamming, while an electromechanical drive generates brake pressure through an electric motor, screw gear, and ball screw mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the external power piston is radially guided in the guide section, then the piston can be axially displaceable without jamming, but the guide section requires additional space and increases device complexity

Engineering Contradiction:
Improveaxial displacability of pistonVSAvoidguide section structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The guide section is integrated directly into the external power cylinder bore, merging the guiding function with the existing cylindrical structure. This eliminates the need for separate guiding components while still providing radial guidance through the cylindrical wall, thus reducing device complexity while maintaining axial displacability.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If the guide section has the same diameter as the external power piston, then radial guidance is achieved, but the piston may jam due to lack of clearance

Engineering Contradiction:
Improveradial guidance of pistonVSAvoidrisk of piston jamming
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The guide section is designed with a slightly larger diameter than the external power piston, creating a small radial clearance. This local dimensional adjustment provides both radial guidance through the cylindrical constraint and sufficient clearance to prevent jamming, resolving the contradiction between guidance and reliability.

Inventive Principle:
Principle #3Local quality

3Ease of operation

If the guide section extends over part of the axial length of the external power cylinder bore, then radial guidance is provided during piston movement, but the overall length of the cylinder bore increases

Engineering Contradiction:
Improveradial guidance during displacementVSAvoidaxial length of cylinder bore
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The guide section extends only over the portion of the axial length where radial guidance is actually needed during piston displacement, rather than covering the entire bore length. This partial extension provides sufficient guidance functionality while minimizing the increase in overall cylinder bore length.

Inventive Principle:
Principle #16Partial or excessive action

4Reliability

If brake fluid channels are provided in the guide section, then lubrication of the piston seal is improved, but the manufacturing complexity of the hydraulic block increases

Engineering Contradiction:
Improvelubrication of piston sealVSAvoidhydraulic block structure
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Brake fluid channels are integrated into the guide section to deliver lubricating brake fluid directly to the piston seal interface. This hydraulic lubrication system improves reliability by ensuring continuous lubrication during piston movement, while the channels are designed to be manufactured using standard drilling and machining processes.

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 design enhances the reliability and efficiency of brake pressure generation and control, ensuring consistent lubrication of the piston seals and preventing dead strokes, thereby improving the overall performance and reliability of the hydraulic vehicle brake system.

Implementation Method 1

a brake fluid channel (11) is provided in the peripheral surface of the external power cylinder bore (4) in the guide section (6) on the pressure side of the external power piston (5), which extends to the piston seal (9)

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

To generate a brake pressure, the external power piston can be displaced in the external power cylinder bore using an external power drive

Methodology Applied
Scientific EffectHydraulic pressure generation: Hydraulic Press

Implementation Method 3

The external power piston is sealed in the external power cylinder bore with a piston seal, in particular a sealing ring

Methodology Applied
Scientific EffectSealing:

Data Source

PatentEP4065439B1Hydraulic block for a hydraulic arrangement of a brake system for a vehicle
Publication Date: 2023.12.13 ROBERT BOSCH GMBH
  • EP4065439B1 patent drawingFigure 1

AI summary

The invention proposes guiding an external-power piston (5) in an external-power cylinder bore (4) of a hydraulic block (2) of a hydraulic unit (1) of an externally powered hydraulic vehicle brake system in only one axially delimited guide section (6) in a radial direction and to form the external-power cylinder bore (4) with a larger diameter axially outside of the guide section (6). A brake fluid channel (11) passes through the guide section (6) up to an opening of the brake fluid line (15).