Actuator Motor Arrangement With Segmented Magnetic And Short-Circuit Braking

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing linear actuators face reliability issues with self-locking under dynamic external forces, particularly when these forces are directional and prolonged, and traditional bolt-on brakes are costly, increase size, and consume more power, while magnetic brakes are inadequate in applications with frequent vibrations and abrupt movements.

Innovation Solution

An electric motor arrangement with a contactless magnetic brake that provides torque at low speeds and incorporates a motor short-circuit arrangement for supplementary braking at high speeds, ensuring reliable self-locking without the need for a mechanical brake, using a DC motor with a worm gear and a movable magnetic brake member between the commutator and the rotor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a magnetic brake is used to provide positioning force, then the actuator self-lock is improved, but the brake must withstand relatively large torque from gravitational forces and vertical movements

Engineering Contradiction:

Improveactuator self-lockVSAvoidbrake torque

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The braking function is divided into two segments: a magnetic brake for low-speed positioning and a motor short-circuit arrangement for high-speed braking. This segmentation allows each component to be optimized for its specific speed range, reducing the torque requirements on the magnetic brake while maintaining reliable self-locking across all operating conditions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention dynamically switches between two braking mechanisms based on operating speed. At low speeds, the magnetic brake provides positioning force; at high speeds, the motor short-circuit arrangement provides braking force. This dynamic approach allows the system to adapt to varying torque requirements across different operating conditions.

Inventive Principle:

Principle #15Dynamics

2Reliability

If a magnetic brake is designed to withstand large torque, then reliability is improved, but the mass and size of the brake increase

Engineering Contradiction:

Improvebrake torque capacityVSAvoidbrake mass

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention replaces a purely mechanical brake system with a hybrid system that uses electromagnetic braking (motor short-circuit arrangement) for high-speed operations. This substitution reduces the mechanical torque requirements on the magnetic brake components, allowing for a more compact and lighter design.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If traditional bolt-on brakes are added to improve self-lock, then reliability is improved, but cost, size, and power consumption increase

Engineering Contradiction:

Improveself-lockVSAvoidactuator structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the braking function with the motor structure itself by using the motor's electromagnetic fields for both propulsion and braking. The magnetic brake and motor short-circuit arrangement are integrated into the motor assembly, eliminating the need for separate bolt-on brake components and reducing overall system complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The motor structure serves multiple functions: it provides both the driving force and the braking force. The electromagnetic fields generated by the motor are utilized for both propulsion and positioning/braking operations, making the motor a multi-functional component that eliminates the need for dedicated brake assemblies.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Speed

If the motor is short-circuited for high-speed braking, then stopping capability is improved, but power consumption increases during braking

Engineering Contradiction:

Improvebraking capabilityVSAvoidpower consumption

Core Design Contradiction:

SpeedVSUse of energy by moving object

Solution Approach 1:

The invention converts the harmful effect of back-EMF generated during motor deceleration into a useful braking force. By short-circuiting the motor windings during high-speed operation, the back-EMF creates a counter-torque that provides effective braking without requiring additional energy input, thus converting a potentially wasteful energy dissipation into a beneficial braking mechanism.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 achieves 100% reliable self-locking with minimal additional brake torque, maintaining compactness and low power consumption, and effectively stops motor movement even during high-speed operation when connection with the controller is lost, enhancing the efficiency of linear actuators.

Implementation Method 1

The motor arrangement is provided with a magnetic brake comprising a rotating magnetic brake member, which is non-positively connected to the shaft, and a pair of opposing brake pole pieces, which are fixed relative to the motor arrangement and which cooperate with the rotating magnetic brake member

Methodology Applied

Scientific EffectMagnetic attraction: Magnetism

Implementation Method 2

The motor control circuit is adapted to short-circuit the motor windings in response to a brake signal

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS10541631B2Electric motor arrangement adapted for use in an actuator and an actuator including the motor arrangement

Publication Date: 2020.01.21 REAC

AI summary

This invention relates to a linear type actuator unit, said actuator unit (100), including an electric motor (1) driving a linear actuator (2) of, said motor (1) having a casing (11), a stator (14,15) fixed to the casing, a rotor (13) fixed to a rotary part (10), preferably a rotary motor shaft (10), wherein said rotary part (10) is arranged to be operatively connected to a reduction gear (5) which drives the mechanical output of the actuator (2), a separate magnetic brake unit (3), said magnetic brake (3) including a rotating brake member (30,31) connected to the motor shaft (10), directly or indirectly, and a plurality of fixed brake members (32, 33), wherein said magnetic brake (3) is arranged to produce a torque that will strive to position a rotary member (10, 20) with said rotating brake member (30,31) into one or more specific angular positions in relation to the fixed brake members (32, 33), and wherein said rotating brake member (30,31) is in the form of a separate annulus (30, 31) attached to said rotary member (10, 20) arranged to brake the motor at low rotational speeds and in that the actuator unit (100) is arranged with a circuitry (101) including a short circuiting arrangement (113, 103) arranged to enable braking of the motor (1) at rotational speeds above low rotational speeds.