Brake Piston Pump Assembly With Zero-Point Position Limiting

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Solution Overview

Problem

In hydraulic vehicle brake systems, determining the position at which a piston stops is challenging, leading to inconsistent brake pressure and compromised driving safety, as the piston pump's movement is difficult to control, affecting the reliability and stability of brake operations.

Innovation Solution

A piston pump group with a lead screw transmission assembly, a follower, and a planetary gear assembly, where a limiting member is used to control the movement of the follower and piston, allowing for zero point calibration and stable brake pressure generation, including a hollow lead screw design to prevent pressure-related issues and ensure structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a piston pump is used for service braking and slip adjustment, then brake pressure can be generated, but the piston stop position is difficult to determine, leading to inconsistent brake pressure

Engineering Contradiction:
Improvebrake pressure consistencyVSAvoidpiston position determination
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

A magnetic marker is attached to the piston and a magnetic sensor is installed on the pump body to detect the piston's position. This intermediary magnetic detection system enables precise measurement of piston position without direct mechanical contact, solving the problem of difficult position determination and ensuring consistent brake pressure generation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the piston pump operates without position control, then the structure is simpler, but driving safety is affected due to unpredictable brake pressure

Engineering Contradiction:
Improvepump structureVSAvoiddriving safety
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The magnetic marker and magnetic sensor form a non-contact detection system that adds minimal structural complexity while providing reliable piston position information. This enables safe and consistent brake pressure generation without requiring complex mechanical position control mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the piston moves without limiting, then the operating range is larger, but collisions may occur affecting service life

Engineering Contradiction:
Improvepiston movement rangeVSAvoidpump service life
Core Design Contradiction:
Adaptability or versatilityVSDuration of action of stationary object

Solution Approach 1:

A limiting member is pre-installed on the pump body at the maximum allowable piston position. This preliminary structural constraint prevents the piston from moving beyond the safe range and colliding with the pump body, thereby extending the service life of the pump while maintaining adequate operating range for brake functions.

Inventive Principle:
Principle #10Preliminary 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

The solution provides stable brake pressure, prevents collisions, ensures the piston's zero point position is accurately calibrated, and prolongs the service life of the piston pump by maintaining structural stability and reducing energy consumption through controlled movement and pressure management.

Implementation Method 1

a lead screw transmission assembly, a follower, and a planetary gear assembly used for transmitting power to the lead screw transmission assembly

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 2

a planetary gear assembly used for transmitting power to the lead screw transmission assembly

Methodology Applied
Scientific EffectPlanetary gear mechanism: Epicyclic Gearing

Data Source

PatentEP4047207B1Piston pump assembly for use in braking system, and control method therefor
Publication Date: 2025.03.26 BYD CO LTD
  • EP4047207B1 patent drawingFigure 1
  • EP4047207B1 patent drawingFigure 2
  • EP4047207B1 patent drawingFigure 3

AI summary

A piston pump group for a brake system and a control method thereof are provided, and the piston pump group includes: a piston (2), a pump body (1) provided with an operating chamber, and a transmission mechanism (3) used for driving the piston (2) to move in the operating chamber, where the transmission mechanism includes a lead screw transmission assembly (32), a follower (33), and a planetary gear assembly (31) used for transmitting power to the lead screw transmission assembly, the follower (33) is fixedly connected to the piston (2), the lead screw transmission assembly (32) is used for driving the follower (33) to move relative to the operating chamber, and a limiting member (34) used for limiting the movement of the follower is disposed between the lead screw transmission assembly (32) and the follower (33).