Brake-Integrated Motor Position Sensing in Limited Axial Space
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Solution Overview
Problem
Conventional brakes and sensors for motor output shafts require significant axial space, necessitating a long shaft to accommodate both components, which is inefficient.
Innovation Solution
A brake integrated with a sensor assembly that minimizes axial space by integrating a sensor within the brake structure, allowing for compact positioning along the rotational axis without increasing the shaft length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional brake and encoder are used separately, then the rotational position can be monitored, but the axial space required increases substantially
Solution Approach 1:
The sensor assembly is integrated directly into the brake structure, with the sensor mounted on the brake plate and the target attached to the rotor. This merging of the position sensing function into the existing brake assembly eliminates the need for a separate encoder mounted on the shaft, thereby reducing the axial space required while maintaining rotational position monitoring capability.
2Ease of manufacture
If the encoder wheel is spaced axially from the brake, then both components can be accommodated, but the motor output shaft becomes relatively long
Solution Approach 1:
The sensor assembly is nested within the brake structure, with the sensor positioned in a recess of the brake plate and the target attached to the rotor. This nesting arrangement allows both the brake and position sensing components to coexist within the same axial space, eliminating the need for additional shaft length to accommodate separate components.
3Measurement precision
If a separate encoder is used in combination with a brake, then position monitoring is achieved, but valuable space is consumed
Solution Approach 1:
The brake assembly is designed to serve multiple functions: providing mechanical braking through the brake plate and armature, and simultaneously enabling rotational position monitoring through the integrated sensor and target. This multi-functionality eliminates the need for a separate encoder, optimizing space utilization while achieving both braking and position monitoring objectives.
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
Enables determination of the rotational position of the motor output shaft without substantial increases in shaft length, optimizing space utilization and integration efficiency.
Implementation Method 1
A spring is configured to urge the armature in a first axial direction towards, and into engagement with, the rotor thereby urging the rotor in the first axial direction towards, and into engagement with, the brake plate to brake rotation of the rotor and rotating body
Implementation Method 2
The electromagnet is configured to urge, when current is delivered to the electromagnet, the armature in a second axial direction away from, and out of engagement with, the rotor
Implementation Method 3
a sensor aligned with the target through the one of the central bore of the brake plate and the central bore of the electromagnet and configured to generate, responsive to the target, position signals indicative of a rotational position of the rotor and rotating body
Data Source
AI summary
A brake includes a rotor rotatably coupled to a rotating body for rotation about a rotational axis. A brake plate and an armature are disposed on opposite sides of the rotor. A spring and an electromagnet urge the armature in opposite directions into and out of engagement with the rotor to move the rotor into and out of engagement with the brake plate and engage and disengage the brake. The brake plate and electromagnet each define a central bore configured to receive the rotating body. The brake is characterized by a target supported on a radially extending face of the rotating body or the rotor and a sensor aligned with the target through the central bore of the brake plate or the electromagnet. The sensor generates, responsive to the target, position signals indicative of a rotational position of the rotor and rotating body.