Wiper Motor Layout with Link Transmission for Compact Vehicle Design

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Solution Overview

Problem

In vehicles requiring size reduction in the longitudinal direction, existing wiper apparatuses face challenges in locating the wiper motor on the rear side due to the need for a direct drive type's rotation shaft to serve as both the pivot and rotation center, and the link type's increased number of parts for transmitting drive power, which complicates size reduction and layout optimization.

Innovation Solution

A wiper apparatus design where the wiper motor is housed below the windshield, with a power transmission mechanism including a swing member and support shafts that allow the wiper motor to be positioned behind the windshield, reducing the number of parts needed for power transmission and enabling the motor to be located on the rear side, while a clutch mechanism disconnects power transmission when torque exceeds a predetermined value to prevent overload.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the wiper motor is located on the rear side of the vehicle to reduce longitudinal size, then the vehicle longitudinal dimension is reduced, but the rotation shaft cannot be positioned behind the windshield in direct drive type apparatuses

Engineering Contradiction:
Improvevehicle longitudinal dimensionVSAvoidshaft positioning complexity
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The patent divides the drive system into separate functional components: the wiper motor is positioned on the rear side while the pivot shaft is positioned at the windshield, connected through a link mechanism. This segmentation allows each component to be optimally positioned independently, resolving the contradiction between compact vehicle dimensions and shaft positioning requirements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A link mechanism serves as an intermediary between the rear-side wiper motor and the windshield-mounted pivot shaft. This intermediary component transmits the rotational drive force from the motor to the wiper arm while bridging the spatial gap, enabling the motor to be positioned behind the windshield without compromising drive transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of moving object

If the link type mechanism is used to position the motor on the rear side, then the motor layout is improved, but the number of parts for power transmission increases

Engineering Contradiction:
Improvemotor positioning flexibilityVSAvoidnumber of power transmission parts
Core Design Contradiction:
Length of moving objectVSQuantity of substance

Solution Approach 1:

The patent combines the link mechanism with the existing pivot shaft assembly, where the link directly connects to the pivot shaft without requiring separate intermediate transmission components. This merging reduces the total number of parts compared to traditional link type mechanisms while maintaining the ability to position the motor on the rear side.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The link mechanism is designed to perform multiple functions simultaneously: it transmits rotational force from the motor, provides structural support for the wiper arm assembly, and enables the motor to be positioned on the rear side. This multi-functionality reduces the need for additional dedicated components, thereby reducing the overall part count.

Inventive Principle:
Principle #6Universality (Multi-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 design improves the layout of the wiper motor, reduces the number of parts, and protects the motor from excessive loads by allowing the wiper motor to be positioned behind the windshield, thus satisfying size reduction requirements and preventing overload, while maintaining effective wiper arm movement.

Implementation Method 1

a worm formed on the armature; and a worm wheel meshing with the worm

Methodology Applied
Scientific EffectWorm gear mechanism: Worm Drive

Data Source

PatentEP2757002B1Wiper device
Publication Date: 2019.10.02 MITSUBA CORP
  • EP2757002B1 patent drawingFigure 1
  • EP2757002B1 patent drawingFigure 2
  • EP2757002B1 patent drawingFigure 3

AI summary

A wiper apparatus is provided with: a wiper arm (14) which is swung about a rotation shaft (18); and a wiper motor (13) for generating drive power to be transmitted to the rotation shaft (18), the wiper apparatus is provided with a power transmission mechanism (19) for transmitting the drive power from the rotation shaft (18) to the wiper arm (14), the power transmission mechanism (19) is provided with: a link member (19a) fixed to the rotation shaft (18) ; and a support shaft (19b) fixed at a position on the link member (19a), which deviates from the rotation shaft (18), and configured to support the wiper arm (14), a coupling section between the support shaft (19b) and the wiper arm (14) is positioned in front of the front end of the front glass (11), and at least one part of the wiper motor (13) is located within the projection region of the front glass (11), thereby suppressing the increase in the number of parts.