DC Motor Brush Holder Assembly Heat Dissipation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing solutions for positioning and supporting DC motor brushes in vehicles, such as windscreen wiper motors, face issues with maintaining precise and constant positioning, heat dissipation, and mechanical stability, leading to wear and potential detachment of the spring blade-support connection, which can cause vibrations and deterioration of the motor components.
Innovation Solution
A DC motor brush axial support assembly featuring a stair-step profiled, electrically conductive spring blade with a carbon fixing zone, seat zone, and connection zone, utilizing positioning and centering orifices and tabs to secure the blade in place, and a planar seat area for effective heat dissipation through a cooling fin configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the leaf spring is overmolded in a plastic support, then the positioning is simplified, but the elasticity of the leaf spring is reduced and heat dissipation is impaired
Solution Approach 1:
The support is divided into a plastic support structure and a separate metal leaf spring component. The leaf spring is not overmolded but rather integrated through positioning orifices and tabs that engage with the support, maintaining its elastic properties while achieving simplified positioning.
Solution Approach 2:
The leaf spring is extracted from the plastic support structure as a separate component. Instead of being embedded in the plastic, it is positioned using dedicated orifices and tabs, allowing it to maintain its full elasticity while still achieving simplified positioning through the integrated design.
2Device complexity
If the leaf spring is overmolded in a plastic support, then the positioning is simplified, but heat dissipation from friction is impaired
Solution Approach 1:
The support structure is segmented into plastic and metal components, with the metal leaf spring serving as a thermal pathway. This segmentation allows heat to conduct through the metal leaf spring to the support structure, improving heat dissipation while maintaining simplified positioning.
Solution Approach 2:
The leaf spring is extracted from the plastic support as a separate metal component, creating a thermal pathway for heat dissipation. The metal material provides superior thermal conductivity compared to plastic, enabling effective heat transfer from the friction zone to the support structure.
3Device complexity
If the conductive blade is directly welded on the power supply circuit, then electrical connection is simplified, but mechanical vibrations are not transmitted to the power supply circuit
Solution Approach 1:
The connection structure is segmented into the conductive blade, positioning tabs, and support components. The tabs provide mechanical engagement that transmits vibrations to the support structure, while the conductive blade maintains electrical connection, separating these two functions into distinct structural elements.
Solution Approach 2:
The vibration transmission function is extracted from the electrical connection structure. The positioning tabs and support structure provide the mechanical pathway for vibration transmission, while the conductive blade focuses on electrical connection, allowing both functions to be optimized independently.
4Strength
If the leaf spring is fixed to the support by a screw, then the connection is secure, but vibrations cause play and potential screw detachment over time
Solution Approach 1:
The connection system is segmented into multiple engagement points: positioning orifices that align components, tabs that provide mechanical interlocking, and retention features that prevent detachment. This segmentation distributes the connection function across multiple elements, reducing stress on any single connection point and preventing vibration-induced failure.
Solution Approach 2:
The screw connection is extracted and replaced with an integrated tab-and-orifice connection system. The positioning orifices and tabs provide secure mechanical engagement that is inherently resistant to vibration, eliminating the risk of screw detachment while maintaining strong connection.
5Reliability
If positioning orifices and tabs are used to secure the blade, then mechanical stability is improved, but device complexity increases
Solution Approach 1:
The positioning orifices and tabs are merged into the plastic support structure as integrated features rather than separate components. This merging achieves mechanical stability through the orifice-tab connection system while avoiding the complexity of additional separate parts, as the support structure itself provides the positioning and retention functionality.
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 solution ensures precise and constant positioning of the brushes, minimizes wear, enhances heat dissipation, and eliminates the risk of spring blade-support connection deterioration, maintaining mechanical stability and reducing the risk of vibrations and motor component deterioration.
Implementation Method 1
the thermal link between the support and the circuit power supply is improved, making it possible to ensure good dissipation of the heat generated by the friction of the brush on the commutator sectors
Implementation Method 2
The direct welding of the electrically conductive blade on the electric power supply circuit of the carbons has the disadvantage of a useless transmission, and ultimately negative, of the mechanical vibrations, generated by the friction of the carbon on the sectors of the collector, to the circuit power supply
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to an assembly for axially holding the brush of a DC motor, comprising at least one electrically conductive blade (1) forming a spring that includes an area (1a) for attaching the brush (C), an area (1b) for seating the blade on a mounting, and an area (1c) for connecting the blade, and a blade mounting (2) including at least one blade seat (2a) onto which the blade forming a spring is inserted and held in position. The area (1a) for attaching the brush and the brush are held in position in a direction that is substantially parallel to the rotational axis (ZZ) of the motor collector. The invention can be used in the production of motors for wipers for automobiles.