Seat Cushion Linkage With Planetary Gear Rigidity Control
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Solution Overview
Problem
Existing seats lack sufficient rigidity, particularly when transitioning between different postures, leading to potential instability and reduced comfort.
Innovation Solution
A seat design incorporating a planetary gear mechanism that restricts rotation of the seat cushion through an actuator, using a transmission mechanism with a sun gear, planetary gear, and internal gear to maintain rigidity during posture changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the seat cushion is made displaceable between different postures using links and connection pipes, then comfort and posture adjustability are improved, but rigidity and structural stability deteriorate
Solution Approach 1:
The seat cushion is designed with dynamic displacement capability between different postures (comfortable posture with front end higher than rear end, and normal posture with small height difference). The cushion frame includes rotatable connection bodies and drive-side links that enable controlled movement between postures while maintaining structural integrity through the planetary gear mechanism.
Solution Approach 2:
A planetary gear mechanism is introduced as an intermediary between the actuator and the cushion frame. This mechanism includes a sun gear connected to the actuator, planetary gears meshing with the sun gear, and an internal gear connected to the second driven-side link. The planetary gear mechanism transmits and amplifies the actuator's rotational force to effectively rotate the connection body and change the seat cushion posture while maintaining rigidity.
2Strength
If a planetary gear mechanism is added to restrict rotation and improve rigidity, then structural stability is improved, but device complexity increases
Solution Approach 1:
The planetary gear mechanism is integrated into the existing cushion frame structure by combining the sun gear with the actuator output, the planetary gears with the connection body, and the internal gear with the second driven-side link. This merging approach allows the rigidity-enhancing mechanism to be incorporated without requiring completely separate structural components, thereby limiting the increase in overall device 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
Enhances the rigidity of the seat by restricting unwanted rotation, ensuring stability and improved comfort during posture transitions.
Implementation Method 1
a planetary gear that has a rotation center revolvable about a center of the sun gear and rotates while meshing with the sun gear; a planetary carrier that rotatably supports the planetary gear and is capable of restricting revolution of the planetary gear
Data Source
AI summary
Provided is a seat having improved rigidity. The seat includes: a first side frame; a second side frame, a connection body; a base member; a first drive-side link; a second drive-side link, an actuator that generates a force for changing an angle between the first drive-side link and the second drive-side link; a first driven-side link that is fixed on the second side frame side of the connection body and rotates integrally with the connection body; a second driven-side link whose first end side is rotatably connected to a second end side of the first driven-side link and whose second end side is rotatably connected to a base member; and a transmission mechanism that mechanically transmits, when a force for rotating the second driven-side link about a connection part between the second driven-side link and the base member acts on the second driven-side link, the force to the connection body.