Windscreen Wiper Motor Brush Assembly for Precise Carbon Brush Positioning

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Solution Overview

Problem

The existing windscreen wiper motor designs face challenges in efficiently positioning and securing the carbon brush holder plate within the transmission housing, leading to complex structural designs and potential misalignment, which can result in suboptimal contact and increased abrasion during operation.

Innovation Solution

The activation device is integrated into the transmission housing as a component, featuring a contact surface that decreases radially with respect to the carbon brush holder plate's longitudinal axis, allowing for a smooth movement of the spring element and ensuring proper alignment through guide elements and counter-elements, and a curved contact section that can engage both sides of the carbon brush for enhanced force distribution and centering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the activation device is integrated into the transmission housing, then the structural design of the carbon brush holder plate is simplified, but the positioning and alignment requirements become more critical

Engineering Contradiction:
Improvestructural design of carbon brush holder plateVSAvoidpositioning and alignment
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The activation device is merged with the transmission housing as an integrated component rather than a separate part. This combining reduces the overall number of components and simplifies the structural design of the carbon brush holder plate, while the transmission housing itself provides the positioning function through its geometry

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The transmission housing serves dual functions: both as a structural enclosure and as an activation device through its geometric features (such as the annular groove and positioning protrusions). The housing's own structure provides the activation and positioning functions without requiring additional dedicated components

Inventive Principle:
Principle #25Self-service

2Ease of operation

If the contact surface is designed with decreasing radial distance in assembly direction, then smooth movement of spring element is achieved, but manufacturing complexity increases

Engineering Contradiction:
Improvemovement of spring elementVSAvoidcontact surface geometry
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The contact surface is designed with a curved profile (decreasing radial distance) rather than a flat surface. This curvature guides the spring element smoothly during assembly, ensuring proper seating and activation while the curve can be integrated into the housing's overall geometry

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Manufacturing precision

If guide elements and counter-elements are used for positioning, then correct angular positioning is ensured, but device complexity increases

Engineering Contradiction:
Improveangular positioningVSAvoidpositioning mechanism
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The guide elements and counter-elements are designed with asymmetric geometries that provide precise angular positioning through their unique shapes. The asymmetric features ensure correct orientation during assembly while being integrated into the overall housing structure

Inventive Principle:
Principle #4Asymmetry

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 simplifies the structural design of the carbon brush holder plate, ensures correct angular positioning, reduces abrasion, and maintains consistent contact pressure, thereby improving the operational efficiency and longevity of the windscreen wiper motor.

Implementation Method 1

a spring element (40) which presses the carbon brush (32) against the collector (18)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the frictional connection of the carbon brush with the side wall of the guide element is removed

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3844848B1Windscreen wiper motor and method of assembling the windscreen wiper motor
Publication Date: 2023.11.01 VALEO SYST DESSUYAGE SAS
  • EP3844848B1 patent drawingFigure 1~2
  • EP3844848B1 patent drawingFigure 3~4
  • EP3844848B1 patent drawingFigure 5~6

AI summary

The invention relates to a windscreen wiper motor (10) with a motor housing (56) of an electric motor (14) being connectable with a transmission housing (12), the electric motor (14) comprising an anchor (16) with a collector (18) and a carbon brush holder plate (26) working together with the collector (18), wherein the carbon brush holder plate (26) has a guide element (46) for a carbon brush (32), wherein the carbon brush (32) is arranged in the guide element (46) so as to be longitudinally displaceable in the direction of a longitudinal axis (34) of the carbon brush (32), with a first end surface (36) of the carbon brush (32) which is designed to be in contact with the collector (18), with, opposite the first end surface (36), a second end surface (38), on which, in an operating position, a spring element (40) is in spring-pretensioned contact in order to press the carbon brush (32) in the direction of the collector (18), wherein the spring element (40), when the carbon brush holder plate (26) is assembled, is in spring-pretensioned contact on a side surface (63) of the carbon brush (32) and presses the carbon brush (32) against the guide element (46) forming a frictional connection (65), so that the first end surface (36) of the carbon brush (32) is positioned at a distance from the collector (18) and wherein an activation device (58) is provided which interacts with the second end surface (38) of the carbon brush (32).