Spring Brake Radial Retention for Actuator Noise Reduction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The existing electromechanical actuator for home automation systems with a spring brake suffers from operating noise and manufacturing defects due to misalignment of the coil spring relative to the input member, output member, and cover, leading to unwanted friction and lack of radial support, which affects the assembly and operation of the spring brake.

Innovation Solution

Incorporating first and second radial retaining elements between the drive tooth and spacer on the input member and cover to ensure radial retention of the coil spring, reducing operating noise and preventing misalignment, thereby maintaining the coil spring's position within the drum and preserving lubrication during assembly and operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If radial retaining elements are added to ensure proper coil spring positioning, then manufacturing precision and reliability improve, but device complexity increases

Engineering Contradiction:
Improvecoil spring alignmentVSAvoidspring brake structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent introduces radial retaining elements as intermediary components between the coil spring and the drum housing. These retaining elements act as mediators that provide radial support to the coil spring, ensuring proper alignment with the input and output members while distributing the mechanical constraints across dedicated structural features rather than relying on tight tolerances alone.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The radial retaining elements are designed to pre-position the coil spring radially before the assembly enters operation. By establishing the correct radial alignment during assembly, the retaining elements prevent misalignment issues from developing during subsequent operation, thereby improving manufacturing precision without requiring complex adjustment mechanisms.

Inventive Principle:
Principle #10Preliminary action

2Stability of the object's composition

If the coil spring is constrained radially by the drum housing, then positioning stability improves, but friction and operating noise increase

Engineering Contradiction:
Improvecoil spring positioningVSAvoidfriction and noise
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The patent segments the radial constraint function from the rotational contact function. The radial retaining elements provide radial support and positioning stability, while the drum housing's internal friction surface is dedicated solely to providing friction for actuation. This segmentation allows each component to perform its specific function optimally without the coil spring simultaneously experiencing both radial constraint and rotational friction from the same surface.

Inventive Principle:
Principle #1Segmentation

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 effectively reduces operating noise and manufacturing defects by ensuring proper radial retention of the coil spring, maintaining its position, and preventing friction-related issues, thus enhancing the reliability and efficiency of the spring brake in home automation systems.

Implementation Method 1

The friction force between the coils of the coil spring and the inner surface of the housing of the drum is increased during the rotational drive of the coil spring in the second direction of rotation

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3717728B1Electromechanical actuator and home automation installation comprising such an actuator
Publication Date: 2021.09.01 SOMFY ACTIVITES SA
  • EP3717728B1 patent drawingFigure 1~2
  • EP3717728B1 patent drawingFigure 3
  • EP3717728B1 patent drawingFigure 4~5

AI summary

An electromechanical actuator comprises a spring brake (15) comprising a helical spring (22), a drum (23), an input member (24), an output member (25) and a cap (33). The drum (23) comprises a housing (26) comprising an inner friction surface (27) configured to cooperate with at least one turn of the spring (22). The input member (24) comprises a driving tooth (31) extending between the input member (24) and the cap (33). The input member (24) or the cap (33) comprises a spacer (34) extending between the input member (24) and the cap (33). The input member (24) comprises a first element (54) for radial retention of the spring (22) that extends between the tooth (31) and the spacer (34) along a first side (C1) of the brake (15). In addition, the cap (33) comprises a second element for radial retention of the spring (22) that extends between the tooth (31) and the spacer (34) along a second side (C2) of the brake (15).