Vehicle Seat Lifter Reducing Width Protrusion via Planetary Gear Nesting
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Solution Overview
Problem
Conventional seat lifters with planetary gear mechanisms protrude significantly outward in the width direction of a vehicle, leading to increased space requirements and potential structural weaknesses.
Innovation Solution
A seat lifter design featuring an inner link and outer link with a coupling rod, a planetary gear mechanism between the inner and outer lower arms, and a drive unit positioned outside the inner link, reducing protrusion by integrating the gear mechanism between the inner and outer lower arms and positioning the drive unit outside the inner link.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the planetary gear mechanism is disposed on the outer side in the width direction of the vehicle, then the operation force transmission unit can effectively transmit power to the planetary gear mechanism, but the amount of outward protrusion of the planetary gear mechanism and operation force transmission unit from the side frame increases significantly
Solution Approach 1:
The patent repositions the planetary gear mechanism from the outer side to the inner side in the width direction, and places the operation force transmission unit above the planetary gear mechanism in the vertical direction. This spatial reconfiguration in multiple dimensions maintains effective power transmission while significantly reducing outward protrusion from the side frame.
Solution Approach 2:
The operation force transmission unit is disposed above the planetary gear mechanism, creating a nested vertical arrangement. This nesting in the vertical direction allows compact packaging of both components without increasing outward protrusion in the width direction, while maintaining functional connectivity for power transmission.
2Ease of manufacture
If the planetary gear mechanism and operation force transmission unit protrude outward significantly, then the components can be adequately spaced for assembly and maintenance, but the space requirements in the width direction of the vehicle increase
Solution Approach 1:
The patent moves the operation force transmission unit from a horizontal arrangement (outer side) to a vertical arrangement (above the planetary gear mechanism). This dimensional change in the vertical direction reduces the width direction footprint while maintaining adequate spacing for assembly and maintenance access.
Solution Approach 2:
The patent integrates the operation force transmission unit and planetary gear mechanism into a compact assembly where the transmission unit is positioned directly above the gear mechanism. This merging of spatial footprints reduces the overall width direction space requirement while maintaining functional separation for assembly purposes.
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 design minimizes outward protrusion of the planetary gear mechanism and drive unit, enhancing structural reinforcement and allowing for efficient up and down movement of the seat frame while maintaining strength at the connection points.
Implementation Method 1
Each planetary gear mechanism includes: a sun gear that rotates by receiving the operation force from the operation force transmission unit; three planetary gears that revolve around the sun gear while rotating on their axes; and a fixed internal gear fixed to the side frame. The rear link has a different number of internal teeth than the fixed internal gear, and functions as a movable internal gear.
Data Source
AI summary
A seat lifter includes: an inner link for changing a height position of an inner lower arm with respect to a floor of a vehicle; an outer link for changing a height position of an outer lower area with respect to the floor; a coupling rod that couples the inner link to the outer link; a planetary gear mechanism capable of causing the coupling rod to rotate relative to the inner lower arm and the outer lower arm; a drive unit capable of driving the planetary gear mechanism; and a power transmission rod that transmits power of the drive unit to the planetary gear mechanism. The planetary gear mechanism is disposed between the inner lower arm and the outer lower arm. The drive unit is disposed outside the inner lower arm in the width direction or outside the outer lower arm in the width direction.