Reversible and Locking Transmission Actuator for Brake Clamping

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Solution Overview

Problem

Existing motorized clamping actuators for vehicle brakes, particularly those with passive holding, suffer from low energy efficiency, increased heating, and the need for more powerful motors due to their non-reversible transmission characteristics, which affects compactness, reliability, and maintenance.

Innovation Solution

A motorized clamping actuator comprising a reversible main transmission and a non-reversible blocking transmission, where the blocking transmission maintains the clamping force after the main transmission is deactivated, using a combination of inclined teeth or threads to achieve irreversible movement, reducing the power requirements of the main motor and allowing for efficient energy use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a non-reversible locking transmission is used to maintain clamping force passively, then energy efficiency is improved and motor power requirements are reduced, but heat generation increases and manufacturing complexity increases

Engineering Contradiction:
Improveenergy efficiencyVSAvoidheat generation
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The transmission system is divided into two independent parts: a reversible main transmission for efficient force application and a non-reversible locking transmission for passive force maintenance. This segmentation allows each transmission to be optimized for its specific function, with the locking transmission being smaller and generating less heat than a full-power irreversible system would require.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system operates in periodic cycles: the reversible transmission applies force during braking events, then the locking transmission maintains the clamping force passively. This periodic operation allows the motor to be deactivated during force maintenance, reducing overall energy consumption and heat generation over the complete operation cycle.

Inventive Principle:
Principle #19Periodic action

2Power

If a non-reversible locking transmission is used to maintain clamping force passively, then motor power requirements are reduced, but device complexity increases

Engineering Contradiction:
Improvemotor power requirementsVSAvoidtransmission complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

Both the reversible main transmission and the non-reversible locking transmission share a common output connection to the clamping piston. This merging of outputs allows the two transmissions to work together in a coordinated manner, reducing overall system complexity compared to having completely separate actuation systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locking transmission serves multiple functions: it maintains passive clamping force, provides mechanical locking, and can assist the reversible transmission during force application. This multi-functionality reduces the need for additional components that would otherwise be required for force maintenance and locking.

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

3Use of energy by moving object

If a reversible main transmission is used for service brake, then energy efficiency is improved, but the ability to maintain force without power is worsened

Engineering Contradiction:
Improveenergy efficiencyVSAvoidforce maintenance capability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The locking transmission acts as an intermediary mechanism between the reversible main transmission and the clamping piston. When the motor is deactivated, the locking transmission engages to maintain the clamping force, while the reversible transmission remains available to re-engage if force adjustment is needed. This intermediary locking mechanism ensures force maintenance without compromising the energy efficiency of the reversible transmission during active operation.

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

The solution enhances energy efficiency, reduces heating, and minimizes the power requirements of the main motor, improving compactness and reliability while maintaining the clamping force without continuous electrical input, suitable for both service and parking brakes.

Implementation Method 1

it can be achieved by choosing a thread or tooth inclination angle that is sufficiently small to be less than the friction angle determined by the pairs of materials in contact

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

a screw-nut mechanism whose output is prevented from rotating. This translation then exerts linear pressure on a brake piston

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentEP3983271B1Passive holding clamping actuator, parking brake, vehicle and method of use
Publication Date: 2023.07.26 HITACHI ASTEMO FRANCE
  • EP3983271B1 patent drawingFigure 1~3
  • EP3983271B1 patent drawingFigure 4~5b
  • EP3983271B1 patent drawingFigure 6a~8b

AI summary

The invention relates to a motorised passive holding clamping actuator for an all-electric brake providing a service and parking brake for a motor vehicle. The actuator comprises a reversible main transmission (T1) and a non-reversible locking transmission (T2), rotated (R1, R2) in order to move a clamping piston in translation (D3, F3), directly or by means of a common transmission (T3) rotated by said main (T1) and locking (T2) transmissions. The main transmission typically actuates the service brake and the parking brake, while the locking transmission moves its irreversibility point in the clamping direction in order to follow the movement of the piston, and to maintain the clamping when the main transmission motor is deactivated. The method proposes to use this locking in order to keep the parking brake clamped or in order to maintain the service brake in case of a continuous or repeated command.