Band Brake Actuator Layout for Compact Stepped Transmissions

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Solution Overview

Problem

There is a need to reduce the size of power transmission devices equipped with stepped transmission mechanisms that utilize a band brake, as existing designs are bulky and inefficient in space utilization.

Innovation Solution

The power transmission device incorporates a band brake and an actuator positioned adjacent to the outer circumference wall and side wall of the transmission mechanism, allowing for a compact design without increasing the device's size by utilizing the available space between these components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a band brake is used in a stepped transmission mechanism, then the transmission can switch between low gear and high gear, but the device size increases

Engineering Contradiction:
Improvegear switching capabilityVSAvoiddevice size
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The actuator is positioned in the radial direction adjacent to the outer circumference wall, utilizing three-dimensional space arrangement to accommodate the band brake mechanism without increasing the overall axial length of the transmission device, thus resolving the contradiction between gear switching capability and device size

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

2Volume of moving object

If the actuator is positioned adjacent to the outer circumference wall and side wall, then the device size is minimized, but the available space for other components is reduced

Engineering Contradiction:
Improvedevice sizeVSAvoidspace utilization
Core Design Contradiction:
Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The band brake mechanism is nested within the space formed by the outer circumference wall and side wall, with the actuator positioned in the radial direction to utilize otherwise wasted space, allowing compact arrangement without compromising the gear switching function

Inventive Principle:
Principle #7Nested doll (Nesting)

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 configuration enables a more compact power transmission device with the band brake and actuator arrangement, maintaining performance while minimizing the device's size in both rotational and radial directions.

Implementation Method 1

a band brake (49), and an actuator (ACT) that drives the band brake (49)

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3940264B1Power transmission device
Publication Date: 2024.07.17 JATCO LTD
  • EP3940264B1 patent drawingFigure 1
  • EP3940264B1 patent drawingFigure 2(a)~2(b)
  • EP3940264B1 patent drawingFigure 3

AI summary

A power transmission device (1) has: a motor (2); a transmission mechanism (3) connected downstream of the motor (2); a counter gear (5) disposed downstream of the transmission mechanism (3); and a body case (9) accommodating the motor (2), the transmission mechanism (3) and the counter gear (5). The transmission mechanism (3) has a band brake (49) and an actuator (ACT) for driving the band brake (49). The body case (9) has an outer peripheral wall (147) surrounding a radial outer periphery of the transmission mechanism (3), and a side wall (143) connected to the outer peripheral wall (147) and extending radially outward from the outer peripheral wall (147). The actuator (ACT) is adjacent to the outer peripheral wall (147) and is adjacent to the side wall (143).