Electric Motor Rotor Brake Integration for Compact Packaging
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Solution Overview
Problem
Conventional electric motors require separate brake assemblies external to the motor, which can complicate design and increase package size, especially when torque, holding, and stopping requirements need to be met within limited spaces.
Innovation Solution
An electric motor design that integrates a brake assembly within the housing, featuring a rotor with a hub, cylindrical, and disk portion, and bearings, allowing the brake to be fixed relative to the housing and selectively couple the disk portion, eliminating the need for a separate brake on the drive shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate brake assembly is used external to the motor, then the braking function is provided, but the package size increases and design complexity increases
Solution Approach 1:
The brake assembly is integrated within the motor housing, combining the braking function with the motor structure. The brake housing is positioned within the motor housing and the brake assembly is fixed relative to the housing, eliminating the need for a separate external brake assembly and reducing overall package size.
Solution Approach 2:
The brake assembly is nested within the motor housing structure. The brake housing with its concentric cylindrical portions is positioned inside the motor housing, and the brake assembly components are arranged within the available space, effectively utilizing the internal volume of the motor.
2Reliability
If a separate brake assembly is used external to the motor, then the braking function is provided, but the design complexity increases
Solution Approach 1:
The brake assembly is integrated within the motor housing, combining the braking function with the motor structure. The brake housing is positioned within the motor housing and the brake assembly is fixed relative to the housing, eliminating the need for a separate external brake assembly and reducing overall package size.
3Volume of stationary object
If the brake assembly is integrated within the housing, then the package size is reduced, but the magnetic field space may be limited
Solution Approach 1:
The brake assembly utilizes the axial dimension within the motor housing. The concentric cylindrical portions of the brake housing are arranged axially, with the first cylindrical portion extending from a first axial position and the second cylindrical portion extending from a second axial position, effectively using the axial space without compromising the radial magnetic field space.
Solution Approach 2:
The brake assembly is positioned in specific locations within the motor housing where it does not interfere with the magnetic field generation. The brake housing with its concentric cylindrical portions is arranged to maximize the use of available space while maintaining the integrity of the motor's magnetic circuit.
Data Source
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AI summary
An example electric motor includes a housing, a stator fixed relative to the housing, a rotor, a brake assembly, a first bearing, and a second bearing. The rotor has a hub portion, a cylindrical portion, and a disk portion. The hub portion of the rotor has a first end, a second end, and a through hole therethrough. The brake assembly is fixed relative to the housing and configured to selectively couple the disk portion of the rotor to the housing. The first bearing is mounted between the first end of the hub portion of the rotor and the disk portion of the rotor. The second bearing is mounted between the second end of the hub portion of the rotor and the disk portion of the rotor.