Windscreen Wiper Drive Device with Knurled Coupling
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Solution Overview
Problem
Existing windshield wiper drive devices often fail to reliably actuate both wiper arms over a long period of operation, leading to inefficiencies and potential mechanical failures.
Innovation Solution
A drive device with an electric drive motor and gearbox that converts rotational movement into a rotary pendulum motion, featuring a first wiper arm coupled to the output shaft and a second wiper arm driven through a transmission linkage, with non-rotatable connection points using knurled or corrugated surfaces for secure coupling, ensuring both wiper arms can operate in the same or opposite directions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a drive unit with electric drive motor and gear unit is used to drive two wiper arms, then the number of drive units is reduced, but the reliability of long-term actuation of both wiper arms deteriorates
Solution Approach 1:
The output shaft is divided into multiple connection points (first connection point for first wiper arm, second connection point for transmission linkage) spaced at different axial positions. This segmentation allows independent attachment of different components to the same drive shaft, enabling one motor to reliably drive multiple wiper arms through separate connection points.
Solution Approach 2:
A transmission linkage with a component acting on the output shaft serves as an intermediary mechanism. The transmission linkage receives rotational movement from the output shaft and converts it into the desired rotary pendulum movement for the second wiper arm, ensuring reliable actuation through mechanical advantage and motion transformation.
2Reliability
If connection points on the output shaft are designed as shaft-hub connections with knurled surfaces, then the coupling security is improved, but the manufacturing complexity increases
Solution Approach 1:
The connection sections on the output shaft are designed with knurled or corrugated surfaces featuring curved or irregular patterns. These surface geometries provide enhanced friction and mechanical interlocking between the shaft and hub connections, preventing rotational slippage while maintaining manufacturability through standard machining or forming processes.
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 ensures reliable and long-term actuation of both wiper arms, enhancing operational efficiency and durability by maintaining a secure, non-rotatable coupling through standardized connection points, reducing mechanical stress and wear.
Implementation Method 1
a drive unit with an electric drive motor and a downstream gear unit, via which the rotational movement of the drive motor is converted into a rotary pendulum movement of an output shaft
Implementation Method 2
The connecting section (18) is knurled, and the connecting section (18) is pressed into a smooth-walled bore (173) of the transmission linkage (8), so that the bore wall (174) is deformed according to the knurling (170)
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a drive device for a windscreen wiping device (1), comprising an electric drive motor (3) and a transmission (4) for driving an output shaft (5), said output shaft supporting the first wiper arm (6) and drives a transmission rod assembly (8) which actuates a second wiper arm (13). The invention relates to, in particular, the connection of the drive shaft to the transmission rod assembly.