Spindle Drive Guide Tube Locking for Low-Cost Motor Vehicle Closures

The connection between the torque tube and housing tube is divided into two independent requirements: axial positioning (preventing separation along the tube axis) and rotational prevention (preventing relative rotation). This segmentation allows different connection mechanisms to address each requirement separately, enabling the use of inexpensive materials like polypropylene that would be unsuitable for traditional adhesive bonding or welding.

The patent replaces chemical bonding methods (adhesive bonding) and thermal joining methods (welding) with a purely mechanical connection system. The bayonet-style connection uses geometric interlocking features that provide both axial and rotational restraint through mechanical means alone, eliminating the need for expensive materials or specialized joining processes.

The patent adopts the philosophy of using inexpensive materials for components where high strength is not critically required. By using a mechanical connection system that distributes loads appropriately, the torque tube can be made from cheap materials like polypropylene, reducing the overall cost of the spindle drive while maintaining sufficient structural integrity for the application.

The patent changes the connection parameters from chemical/thermal bonding to mechanical interlocking. This parameter change allows the torque tube material properties to be optimized for cost rather than maximum strength, as the mechanical connection provides the necessary structural support through its geometry and engagement features.

The patent merges multiple functions into the single torque tube component: axial guidance of the spindle nut, rotational support (anti-rotation safeguard), and structural connection to the housing tube. The bayonet-style mechanical connection integrates axial positioning and rotational prevention into one unified system, reducing overall device complexity compared to having separate components for each function.

The torque tube is designed as a multi-functional component that simultaneously provides axial guidance, rotational restraint, and structural support. The mechanical connection system serves multiple purposes: it positions the torque tube axially, prevents relative rotation, and transfers loads between components. This multi-functionality reduces the number of separate parts needed, simplifying the overall spindle drive design.