Adjusting device for a lumbar support and method of adjusting a lumbar support
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Solution Overview
Problem
Conventional lumbar support adjusting devices require significant installation space for electric motors and pulleys, making them bulky and complex to install, especially in vehicle seat backrests where space is limited.
Innovation Solution
A lumbar support adjusting device featuring a pair of guide members with a displaceable motor and a shaft with a structured exterior surface, allowing the motor to move along the guide members with the adjusting member, reducing the need for dedicated installation space and incorporating a flexible shaft to minimize breakage risk under load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a Bowden cable is used to couple the power actuator to the lumbar support, then the lumbar support can be adjusted, but the installation space required for the electric motor or pulley increases significantly
Solution Approach 1:
The motor is integrated directly into the adjusting member, merging the drive mechanism with the adjustment component. This eliminates the need for separate Bowden cable systems and reduces installation space requirements by consolidating components that were previously distributed across different locations.
Solution Approach 2:
The patent replaces the Bowden cable mechanical transmission system with a direct-drive mechanism where the motor is mounted on the adjusting member itself. This substitution eliminates the intermediate cable and pulley components, reducing the overall space required for the power actuation system.
2Force
If the electric motor is dimensioned to provide sufficient force for Bowden cable adjustment, then the lumbar support can be adjusted under load, but the installation space required increases
Solution Approach 1:
By mounting the motor directly on the adjusting member, the force generation and adjustment functions are combined in a single integrated unit. This eliminates the need for oversized motors required to pull Bowden cables under load, as the motor directly drives the adjustment mechanism without mechanical transmission losses.
3Ease of operation
If the motor is installed spaced from the lumbar support to accommodate Bowden cable routing, then the cable can be drawn in or played out, but the installation becomes more complex
Solution Approach 1:
The patent extracts the Bowden cable intermediate transmission elements from the system and replaces them with a direct-drive motor mounted on the adjusting member. This elimination of intermediate components simplifies the installation process by removing the need for complex cable routing through the seat backrest structure.
4Device complexity
If a rigid shaft is used for the drive mechanism, then the motor can be mounted on the adjusting member, but the shaft may break under load conditions
Solution Approach 1:
The patent changes the physical parameter of the shaft from rigid to flexible, allowing it to bend and absorb loads without breaking. This flexible shaft maintains the simplified drive mechanism structure while significantly improving reliability under various load conditions, including unexpected lateral or longitudinal forces.
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 enables a compact and efficient adjustment mechanism that reduces the risk of motor breakage and simplifies installation by allowing the motor to move with the adjusting member, while maintaining effective lumbar support adjustment capabilities.
Implementation Method 1
The shaft may be configured such that, when a normal force of about 250 N is exerted onto the lumbar support, the shaft is still elastically deformed
Data Source
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AI summary
An adjusting device (3) for a lumbar support comprises a pair of spaced guide members (4, 5), an adjusting member (14) coupled to the pair of guide members (4, 5), and a drive mechanism (30, 40) for effecting an adjustment of the lumbar support. The adjusting member (14) is displaceable along the pair of guide members (4, 5) and configured such that the lumbar support is adjusted when the adjusting member (14) is displaced. The drive mechanism (30, 40) comprises a motor (31, 41), which is provided on the adjusting member (14) so as to be displaceable along the guide members (4, 5) jointly with the adjusting member (14). The motor (31, 41) may be coupled to a shaft (32, 42) having a structured exterior surface, the drive mechanism (30, 40) being configured to effect a relative displacement between the adjusting member (14) and the shaft (32, 42).