Friction Brake Torque via Speed Reducer

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Solution Overview

Problem

Existing friction brakes configured to reduce rotation of a wheel driven by a motor unit are large due to the need for significant pressing force to apply brake torque, which increases the size and weight of the brake system.

Innovation Solution

A friction brake design that incorporates a speed reducer to increase brake torque applied to the wheel, allowing for a smaller pressing force and reduced size, featuring a pressing device with a hydraulic-pressure source and friction plates that generate a large frictional force with a rotor, and a brake cooling mechanism to manage heat, while using materials like aluminum alloy for weight reduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a friction brake is configured to reduce rotation of a wheel driven by a motor unit, then the brake torque is increased by the speed reducer, but the pressing force required is significant which increases the size of the friction brake

Engineering Contradiction:
Improvebrake torqueVSAvoidsize of friction brake
Core Design Contradiction:
PowerVSVolume of moving object

Solution Approach 1:

A reaction force receiving member is introduced as an intermediary component that receives the reaction force from the pressing member and transmits it to the housing. This mediator allows the pressing force to be effectively utilized while reducing the overall size of the friction brake assembly, as the reaction force is now transmitted through a dedicated pathway rather than requiring a larger structural framework.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The reaction force receiving member extends in the axial direction of the rotor, utilizing the axial dimension to transmit the reaction force. This dimensional approach allows the brake system to manage forces more efficiently in three-dimensional space, reducing the radial and lateral dimensions of the overall brake assembly.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If a lever and actuator mechanism is used to apply pressing force to the friction plates, then the brake can be actuated, but the device complexity increases

Engineering Contradiction:
Improvebrake actuationVSAvoidcomplexity of pressing device
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The complex lever and actuator mechanism is extracted and replaced with a more straightforward pressing member connected to a hydraulic-pressure source. This extraction of the overly complex mechanism and replacement with a simpler hydraulic system maintains the brake actuation functionality while significantly reducing the overall device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The mechanical lever and actuator system is replaced with a hydraulic-pressure source that directly applies pressing force through a pressing member. This substitution of the mechanical system with a hydraulic system simplifies the overall mechanism while maintaining effective brake actuation capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 design achieves a smaller and lighter friction brake with reduced pressing force requirements, increased brake torque efficiency, and effective heat management, resulting in improved performance and reduced wear on components.

Implementation Method 1

a pressing device configured to press the plurality of friction plates against the rotor

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The drive source includes a hydraulic-pressure source configured to generate hydraulic pressure to move the pressing member in the axial direction

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentEP3614010B1Vehicle-mounted apparatus
Publication Date: 2022.10.19 TOYOTA JIDOSHA KK
  • EP3614010B1 patent drawingFigure 1
  • EP3614010B1 patent drawingFigure 2
  • EP3614010B1 patent drawingFigure 3

AI summary

A friction brake (6) for reducing the rotation of a vehicle wheel driven by a motor unit (4) comprising a drive motor (10) and a speed reducer (12) by reducing the rotational speed of an output shaft (14) of the drive motor (10), the friction brake (6) comprises: - at least one rotation disc (36) for rotating integrally with the output shaft (14) of the drive motor (10); - a housing (30) that is a non-rotatable member; - at least one friction plate (32,34) held by the housing (30) so as to be movable relative to the housing (30) in the axial direction such that rotation of the at least one friction plate (32,34) relative to the housing (30) about its axis is restricted; and - a pressing device (38;100) configured to press the at least one friction plate (32,34) against the at least one rotation disc (36).