Quick Adjust Power Adjuster Split Nut Mechanism
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Solution Overview
Problem
Existing power seat track assemblies in automotive vehicles only provide powered fore and aft movement, lacking a convenient mechanism for quick manual adjustment from a passenger-adjusted position to a full forward easy entry position.
Innovation Solution
A quick adjust power adjuster system that includes a split nut and release mechanism, allowing the upper track to be manually moved by decoupling from the lead screw, enabling axial sliding without motor input, and relocking for powered operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional gearbox or drive assembly is used for powered seat movement, then the seat can be adjusted fore and aft with motor control, but the mechanism cannot be quickly manually moved to a full forward easy entry position
Solution Approach 1:
The system dynamically switches between two operational states: a locked state where the split nut engages the lead screw for powered motor-driven adjustment, and an unlocked state where the release mechanism disengages the split nut from the lead screw, allowing free manual movement of the upper track. This dynamic state change enables both powered and manual operation modes without permanent structural modification.
Solution Approach 2:
The nut is divided into two separate halves (split nut) that can be independently positioned. When the release mechanism is activated, the two halves separate to disengage from the lead screw, enabling manual movement. When released, the halves come together to engage the lead screw for powered operation. This segmentation allows the same component to serve both locked and unlocked functions.
2Speed
If the upper track is fixedly secured to the seat cushion for powered movement, then motor control is achieved, but quick manual movement to forward-most position is prevented
Solution Approach 1:
The release mechanism acts as an intermediary component that mediates between the motorized drive system and the upper track. It provides a simple manual interface (such as a button or lever) that, when actuated, triggers the disengagement of the split nut from the lead screw, allowing rapid manual movement. This intermediary enables quick mode switching without requiring complex direct coupling mechanisms.
3Adaptability or versatility
If the split nut is used to allow both powered and manual operation, then versatility is improved, but the manufacturing complexity increases
Solution Approach 1:
The split nut is manufactured as two separate halves rather than a single monolithic component. This segmentation simplifies the manufacturing process for each individual half while enabling the versatile function of engagement and disengagement. The two halves can be produced using standard machining processes and then assembled together with the release mechanism.
Solution Approach 2:
The split nut assembly is designed to perform multiple functions: it serves as a threaded fastener for powered operation, a locking mechanism when engaged, and a disengageable connector when unlocked. This multi-functionality is achieved through the same basic component structure, reducing the need for separate specialized components for different operation modes.
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
Enables both powered and manual fore and aft movement of the seat assembly, facilitating easy access and entry into the vehicle by allowing the seat to be manually adjusted to a forward-most position without the need for motor operation.
Implementation Method 1
An elongated lead screw extends axially between opposite fore and aft ends and is adapted to be fixedly secured to the lower track. A driven assembly is selectively coupled to the lead screw for axial travel along the lead screw between the fore and aft ends.
Implementation Method 2
The friction between the split nut halves and the lead screw threads provides axial positioning and prevents unintended movement.
Data Source
AI summary
A power adjuster for adjusting an upper track relative to a lower track of a seat track assembly. An elongated lead screw extends axially between opposite fore and aft ends and is fixedly secured to the lower track. A driven assembly is selectively coupled to the lead screw for axial travel along the lead screw between the fore and aft ends. A drive assembly is fixedly coupled to the upper track and operatively coupled to the driven assembly for selectively rotating the driven assembly in opposite first and second directions for axial travel along the lead screw in a power operation mode. A release mechanism is coupled to the upper track and operable between a locked condition.