Lumbar Support System Using Threaded Member and Flexmat
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Solution Overview
Problem
Existing lumbar support systems in vehicle seats often suffer from poor efficiency due to the use of Bowden cables, requiring large and heavy motors, and are noisy during operation.
Innovation Solution
A lumbar support system that includes a frame, movable support elements anatomically contoured for lumbar and pelvic support, and a motor-driven spindle mechanism with flexible cables, allowing for precise adjustment and reduced noise through a worm gear and threaded member configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a Bowden cable is used to move the lumbar support, then the support can be adjusted, but the system efficiency deteriorates and the motor size and weight increase
Solution Approach 1:
The patent removes the Bowden cable from the system and replaces it with a direct motor-to-threaded-member connection. This extraction of the inefficient cable mechanism eliminates the energy losses associated with cable friction and mechanical advantage, allowing the motor to directly drive the lumbar support movement through the threaded member.
Solution Approach 2:
The patent substitutes the Bowden cable mechanical transmission system with a motor-driven threaded member system. The threaded member converts rotational motor motion directly into linear movement of the lumbar support, replacing the indirect cable-pulley mechanism with a more efficient screw-mechanism that reduces energy loss and eliminates the need for large motors.
2Ease of operation
If a Bowden cable system is used, then lumbar support adjustment is achieved, but the system becomes noisy during operation
Solution Approach 1:
The patent extracts the noisy Bowden cable components (cables, pulleys, and associated mechanical linkages) from the system and replaces them with a compact motor-driven threaded member assembly. This removal of the cable system eliminates the sources of noise generated by cable friction, pulley rotation, and mechanical play.
Solution Approach 2:
The patent replaces the noisy mechanical cable transmission system with a quieter motor-driven threaded member system. The threaded member provides smooth, controlled movement with minimal mechanical noise, as the screw mechanism inherently dampens vibrations and eliminates the slapping and rubbing sounds characteristic of cable systems.
3Force
If large motors are used to drive the lumbar support, then sufficient force is achieved, but the system complexity and component count increase
Solution Approach 1:
The patent changes the mechanical advantage parameter by eliminating the cable system's inherent mechanical disadvantage. By using a motor directly connected to a threaded member, the system achieves high force output with a smaller motor, as the threaded member's screw mechanism provides natural mechanical advantage without requiring oversized drive components.
Solution Approach 2:
The patent removes the Bowden cable system and its associated large motors from the design. The extraction of this over-engineered subsystem reduces component count and simplifies the overall system while maintaining sufficient actuation force through the more efficient direct-drive threaded member mechanism.
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 system provides efficient, quiet, and adjustable lumbar support by translating the motor's rotational motion into axial movement of support elements, enhancing occupant comfort and reducing system complexity.
Implementation Method 1
a threaded member operatively engaged with the motor such that the motor rotates the threaded member about an axis. First and second traveling members are engaged with the threaded member such that rotation of the threaded member translates the first and second traveling members in opposite axial directions along the threaded member.
Implementation Method 2
The system also includes first and second flexible cables, each having a first end coupled to an associated one of the first and second traveling members for movement therewith, a second end coupled to the fixed frame, and an intermediate portion operatively associated with the first support element.
Data Source
AI summary
A lumbar support system for a seat backrest includes a fixed frame and a flexmat coupled to the fixed frame. The flexmat includes first and second outer wires and a plurality of transverse wires extending between the outer wires. A support element is coupled to a lower portion of the flexmat below the plurality of transverse wires for concurrent movement with the flexmat from a first position to a second position. The support element is anatomically contoured for lumbar and pelvic support, and the support element is constructed of a more rigid material than the flexmat.