Spindle Drive Assembly with Deformed Tube Section
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Solution Overview
Problem
Existing spindle drives for motor vehicle seat adjustments require complex assembly processes due to the mismatched locations of the motor-driven spindle and actively driven nut unit, leading to increased effort and potential issues with jamming and dirt collection.
Innovation Solution
A method for producing a spindle drive with a plastic nut and retainer where the nut has recesses on its outer jacket, allowing a tube section to be deformed to create a positive-fit connection without the need for threading, enabling a cost-effective and simple assembly process with adjustable axial and torsion strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the spindle and nut unit are allocated to different rails with complex assembly positioning, then the drive function is achieved, but the assembly effort increases significantly
Solution Approach 1:
The patent combines the retainer and nut into a single integrated nut unit that is self-positioning. The retainer forms an integral part of the nut structure with recesses that directly receive the spindle, eliminating the need for separate assembly positioning steps and reducing overall assembly complexity while maintaining the distributed rail configuration.
2Weight of moving object
If the tube section has thin wall thickness to reduce weight, then material usage is optimized, but connection strength may be compromised
Solution Approach 1:
The patent applies local quality by providing reinforcement ribs or protrusions at specific locations on the tube section that correspond to the recesses. These localized reinforcements concentrate material only where connection strength is needed (at the joining points) while maintaining thin wall thickness in other areas, thus optimizing the weight-strength ratio.
3Strength
If the tube section is deformed to create positive-fit connection, then connection strength is improved, but manufacturing complexity increases
Solution Approach 1:
The patent incorporates the deformation features (recesses with reinforcement ribs) into the tube section during its initial forming process. This preliminary action creates the positive-fit connection geometry before assembly, so that the deformation required for strong connection is already built into the component structure rather than requiring complex post-assembly deformation operations.
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
This method simplifies the connection between the retainer and nut, allowing for different material usage, reduced assembly effort, and effective prevention of jamming and dirt accumulation, while providing a strong and reliable mechanical connection.
Implementation Method 1
the tube section, in the areas in which the recesses of the nut are located, is deformed into the area of the recesses
Data Source
AI summary
In the method for producing a spindle drive of an adjustment device of a motor vehicle seat, the adjustment device comprises a spindle and a nut unit. The nut unit comprises a nut made from plastic and a retainer in which the nut is retained. The nut has an internal thread which is in engagement with the spindle and has recesses in its outer jacket. The method comprises the following steps: the tube section is pushed over the nut during assembly, the nut is located within the tube section, the tube section, in the areas in which the recesses of the nut are located, is deformed into the area of the recesses and a portion of material of the tube section is located in the recesses.