Actuator

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Solution Overview

Problem

Existing actuators are mechanically complex, heavy, and have a soft force characteristic curve due to the use of pre-tensioned scroll springs with many coils, making them inefficient and costly for compact designs.

Innovation Solution

An actuator design featuring a transmission section with a drive gear, transmission gear, and driven gear in the same effective plane, utilizing a helical or spiral spring with fewer turns for a high spring hardness, and a toothed gear mechanism with distinct transfer functions to provide a constant closing force and reduce rotation angle dependency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a pre-tensioned scroll spring with a large number of coils is used as the return spring, then a linear force course is achieved, but the spring becomes mechanically complex and very heavy

Engineering Contradiction:
Improvelinearity of force courseVSAvoidweight of return spring
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent changes the key parameter of the return spring from a scroll spring with many coils to a torsion spring with few coils. This parameter change maintains the linear force course requirement while dramatically reducing the weight and mechanical complexity of the spring component.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses a different spring mechanism (torsion spring) that copies the essential function of providing a linear force course without replicating the complex multi-coil scroll spring structure. The torsion spring achieves the same functional outcome through a fundamentally different design approach.

Inventive Principle:
Principle #26Copying

2Reliability

If a pre-tensioned scroll spring with a large number of coils is used as the return spring, then a linear force course is achieved, but the spring becomes mechanically complex

Engineering Contradiction:
Improvelinearity of force courseVSAvoidmechanical complexity of return spring
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent fundamentally changes the type and configuration parameters of the return spring, transitioning from a scroll spring design with many coils to a torsion spring design with few coils. This parameter transformation achieves the desired linear force course while eliminating the mechanical complexity associated with scroll springs.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The torsion spring copies the functional behavior of providing a linear force course without copying the complex structural design of the scroll spring. This allows the system to achieve the same performance outcome through a simpler mechanical implementation.

Inventive Principle:
Principle #26Copying

3Volume of moving object

If the drive gear, transmission gear section, and driven gear section are arranged in the same effective plane, then a compact design is achieved, but the transmission ratio variation with rotation angle becomes more challenging to control

Engineering Contradiction:
Improvecompactness of actuatorVSAvoidtransmission function design complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent employs dynamic transmission functions in the gear tooth portions that allow the transmission ratio to vary intentionally with rotation angle. This dynamic approach enables compact in-plane arrangement of gears while providing controlled variation in transmission ratio to compensate for spring force characteristics.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the transmission ratio parameter dynamically through the rotation angle, using differently shaped tooth portions on the transmission gear. This allows the system to maintain compact geometry while achieving the necessary transmission characteristics through parameter variation.

Inventive Principle:
Principle #35Parameter changes

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 design results in a compact, cost-effective actuator with a linear force curve, reduced mechanical complexity, and lower weight, enhancing reliability and installation space efficiency while maintaining a high torque output.

Implementation Method 1

the actuator also having a restoring spring, which is used to provide a closing force acting on the actuating element

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The transmission section has at least a drive gear, a transmission gear and a driven gear. The transfer gear has a drive tooth portion and a driven tooth portion, wherein the drive tooth portion meshes with the drive gear and the driven tooth portion meshes with a second transfer function in the output gear.

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Data Source

PatentEP3569894B1Actuator
Publication Date: 2021.07.07 SIEMENS SCHWEIZ AG
  • EP3569894B1 patent drawingFigure 1
  • EP3569894B1 patent drawingFigure 2
  • EP3569894B1 patent drawingFigure 3

AI summary

The present invention relates to an actuator (1) comprising a drive element (2), a transmission section (10), and an actuating element (3), wherein the drive element (2) is mechanically operatively connected to the actuating element (3) via the transmission section (10) for driving the actuating element (3), the actuator (1) further comprising a return spring (4) which is mechanically operatively connected to the actuating element (3) for providing a closing force (6) acting on the actuating element (3). The transmission section (10) comprises at least one drive gear (11), one transmission gear (20), and one output gear (12). The transmission gear (20) comprises a drive tooth section (21) and an output tooth section (23), wherein the drive tooth section (21) meshes with a first transmission function (22) into the drive gear (11) and the output tooth section (23) meshes with a second transmission function (24) into the output gear (12).Furthermore, the first transfer function (22) and the second transfer function (24) are different. The drive gear (11), the drive tooth section (21), the driven tooth section (23) and the driven gear (12) are arranged in the same plane of action (40).