Worm Gear Actuator Structure Without Coil Springs or Foam Blocks

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Solution Overview

Problem

Existing actuators that convert rotating motion into linear reciprocating motion are complex, costly, and suffer from heat-related issues due to the use of coil springs and foam plastic blocks, which affect braking performance and heat dissipation, leading to structural damage and vibrations.

Innovation Solution

The actuator design replaces coil springs with a transmission mechanism using a gasket and limiting structures, and eliminates foam plastic blocks, instead using a gasket member and elastic cushions to secure the motor, reducing friction and heat generation, and incorporating a reversible electric motor with a worm wheel and connector to achieve efficient linear motion conversion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a coil spring is employed in the transmission member to exert a braking force, then the braking effect is achieved, but friction generates heat which damages the surrounding structure and degrades braking performance

Engineering Contradiction:
Improvebraking forceVSAvoidheat generation
Core Design Contradiction:
ForceVSTemperature

Solution Approach 1:

The patent replaces the coil spring-based mechanical braking system with a frictionless magnetic braking mechanism. The magnetic brake uses magnetic attraction force between a magnet and a ferromagnetic material to provide braking force without physical contact, thereby eliminating friction-generated heat while maintaining effective braking capability.

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

2Stability of the object's composition

If a foam plastic block is used to secure the electric motor in the cabinet, then the motor is firmly held, but heat dissipation performance degrades and the foam block distorts or melts when heated

Engineering Contradiction:
Improvemotor securingVSAvoidheat dissipation
Core Design Contradiction:
Stability of the object's compositionVSTemperature

Solution Approach 1:

The patent removes the foam plastic block entirely from the motor mounting structure. Instead, the motor is secured using alternative mounting methods such as brackets or direct mechanical fastening to the cabinet, which do not interfere with heat dissipation and are resistant to thermal distortion or melting.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the foam plastic block entirely covers the electric motor sides, then the motor is tightly received, but heat dissipation is degraded and vibrations occur when the foam block distorts or melts

Engineering Contradiction:
Improvemotor positioningVSAvoidvibrations
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent eliminates the foam plastic block that was entirely covering the motor sides. The motor is positioned and secured using rigid mounting structures that maintain stable positioning without thermal distortion, preventing vibrations caused by foam block degradation.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of operation

If a traditional transmission mechanism with coil spring is used, then motion conversion is achieved, but the actuator becomes structurally and operably complicated and costly in fabrication

Engineering Contradiction:
Improvemotion conversionVSAvoidactuator structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent removes the coil spring from the transmission mechanism, simplifying the overall actuator structure. The motion conversion function is achieved through a streamlined transmission system that eliminates the need for the complex coil spring-based braking and positioning mechanism, reducing both structural complexity and fabrication cost.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical coil spring braking system with a magnetic braking mechanism, simplifying the transmission member design. This substitution reduces the number of moving parts and structural complexity while maintaining the necessary motion control and conversion functions.

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

This design enhances the efficiency and reliability of the actuator by reducing friction, heat, and vibrations, leading to improved performance and cost-effectiveness, while maintaining effective linear motion conversion without the drawbacks of coil springs and foam plastic blocks.

Implementation Method 1

a magnetic brake is provided in the transmission member instead of the coil spring

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Implementation Method 2

two elastic cushions are provided on the bottom wall of the housing, and the motor is positioned on the elastic cushions

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3739239B1An actuator for converting a rotating motion into a linear reciprocating motion
Publication Date: 2024.02.14 ZHEJIANG JIECHANG LINEAR MOTION TECH
  • EP3739239B1 patent drawingFigure 1
  • EP3739239B1 patent drawingFigure 2A
  • EP3739239B1 patent drawingFigure 2B

AI summary

The present invention relates to an actuator for converting a rotating motion into a linear reciprocating motion, comprising: a motor (110) having a front end and an output worm shaft (112) extending from the front end; a transmission mechanism (120') operatively coupled to the output worm shaft (112) of the motor (110) for converting a rotating motion of the motor (110) into a linear reciprocating motion, wherein the transmission mechanism (120') comprises: a bracket (121) mounted onto the front end of the motor (110), having a base (122), and a fixing pin (1221) extending from the base (122) along a direction perpendicularly to the worm shaft (112) of the motor (110); a worm wheel (123') having a first side (1231'), an opposite, second side (1232'), and a recess (124') defined in the second side (1232'), the worm wheel (123') being connected onto the base (122) through the fixing pin (1221) on the first side (1231'), and meshing with the worm shaft (112) of the motor (110); and a connector (127') having a first end portion (1271') and a second end portion (1272') extending oppositely from the first end portion (1271'); and wherein the transmission mechanism (120') is devoid of a coil spring; and a housing (151) and mounting means for mounting the motor (110) in the housing 150, wherein the mounting means is devoid of a foam plastic block, characterized in that the worm wheel (123') further comprises limiting structures (1233') spaced-apart formed on walls of the recess (124'); the transmission mechanism (120') further comprises a gasket (125') having flanges (1251') radially protruded from a perimeter (1252') of the gasket (125), placed in the recess (124') of the worm wheel (123') such that each limiting structure (1233') is tightly positioned between two adjacent flanges (1251'); and the first end portion (1271') of the connector (127') is formed with engaging posts (1271'), and placed in the recess (124') of the worm wheel (123') such that each engaging post (1271') is tightly positioned between two adjacent flanges (1251') and between two adjacent limiting structures (1233'), whereby each flange (1251') of the gasket (125) is tightly positioned between a respective limiting structure (1233') and a respective engaging post (1271').