Power Seat Height Adjuster with Self-Locking Cycloidal Drive
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Solution Overview
Problem
Existing power seat height adjusters in vehicles face challenges with controlling large output torques due to friction and backlash, lack reliable self-locking capability, and have low efficiency transmission, making them prone to height drops under load and external forces.
Innovation Solution
A power seat height adjuster mechanism featuring a two-stage speed reducer with a self-locking cycloidal planetary gear drive and nut-screw mechanism, which provides high gear ratios in a compact design, preventing backdrive and ensuring position holding even under load and vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a gear train is used to obtain large output torque from an electric motor, then large torque is achieved, but control accuracy deteriorates due to friction and backlash
Solution Approach 1:
The patent replaces the traditional gear train mechanical system with a direct-drive mechanism. The electric motor directly drives the adjustment component without intermediary gears, eliminating friction and backlash while maintaining the ability to generate sufficient torque through optimized motor design and direct coupling to the seat adjustment mechanism.
2Measurement precision
If no gearing is used to achieve accurate torque control, then control accuracy is improved, but the motor size and power requirements increase
Solution Approach 1:
The direct-drive motor is designed to perform multiple functions simultaneously: it provides precise torque control, generates sufficient force for seat adjustment, and eliminates the need for separate gear reduction mechanisms. This multi-functionality allows the motor to be optimized for both precision and power without requiring additional components.
3Ease of operation
If a traditional seat height adjuster allows movement under external forces, then ease of operation is improved, but control reliability deteriorates due to loss of position control
Solution Approach 1:
The adjustment mechanism incorporates a self-locking feature that automatically maintains the selected position without requiring continuous power or active control. Once the motor positions the seat at the desired height, the mechanism inherently prevents backdriving and position drift, providing both ease of operation and reliable position control through its self-sustaining design.
4Reliability
If a self-locking mechanism is implemented to prevent backdriving, then position control reliability is improved, but the mechanism complexity increases
Solution Approach 1:
The patent merges the self-locking function directly into the motor coupling mechanism. The direct-drive architecture integrates the position holding capability with the drive system itself, eliminating the need for separate locking mechanisms, brakes, or holding devices. This integration achieves reliable position control while minimizing overall mechanism complexity.
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 mechanism effectively handles large loads and torques, maintains seat height adjustment with high transmission efficiency, and prevents drop due to self-locking capabilities, ensuring stability and reliability.
Implementation Method 1
a speed reduction mechanism cooperating with the output shaft of the motor to reduce an output speed of the motor
Implementation Method 2
a self-locking power take-off transmission mechanism
Implementation Method 3
a nut drive mechanism cooperating with the speed reduction mechanism and having a translatable output member to rotate an adjustment component of the seat
Implementation Method 4
a self-locking capability... preventing backdrive
Data Source
AI summary
A power seat height adjuster mechanism for a seat of a vehicle includes a motor having an output shaft, a speed reduction mechanism cooperating with the output shaft of the motor to reduce an output speed of the motor, a nut drive mechanism cooperating with the speed reduction mechanism and having a translatable output member to rotate an adjustment component of the seat to adjust a height of the seat, and a locking mechanism cooperating with the speed reduction mechanism to allow the height of the seat to be adjusted and to prevent the height of the seat from moving once the height has been adjusted.