Taper Lock Linear Drive Assembly for Precise Torque Transmission
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Solution Overview
Problem
Current linear actuators face challenges in achieving precise torque transmission and runout control due to complex and costly interface methods between screws and motors, which also make assembly and disassembly time-consuming and prone to damage.
Innovation Solution
A linear actuator system utilizing a taper lock apparatus with a screw having a tapered end and a compression fitting with expandable slits, allowing for secure torque transmission and axial load retention without the need for critical tolerances, enabling fast assembly and disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a press fit method is used to interface screw to motor, then torque transmission is achieved, but critical tolerances are required which increase cost and complexity
Solution Approach 1:
The patent changes the geometric parameters of the interface by introducing a tapered configuration instead of a cylindrical press fit. The taper angle allows for torque transmission through friction while accommodating larger tolerances, eliminating the need for critical dimensional controls required by traditional press fits.
Solution Approach 2:
The patent introduces asymmetry through the tapered interface geometry, where the diameter varies along the length of the connection. This asymmetric shape creates a self-centering effect and allows torque transmission without requiring the symmetric, precision-machined interfaces of conventional press fits.
2Strength
If a weld method is used to interface screw to motor, then torque transmission and strength are improved, but assembly complexity and labor intensity increase
Solution Approach 1:
The patent replaces the thermal welding process with a mechanical tapered interface system. Instead of using heat and metallurgical bonding, the solution uses mechanical friction and geometric interlocking through the taper to achieve torque transmission, eliminating welding equipment and specialized labor requirements.
Solution Approach 2:
The patent segments the connection interface into distinct functional zones: the tapered surface for torque transmission, the threaded bore for axial retention, and the expansion mechanism for securing the screw. This segmentation allows each feature to be manufactured independently using standard machining operations rather than requiring complex welded assemblies.
3Ease of manufacture
If an adhesive method is used to bond screw to motor, then assembly is simplified, but torque transmission capability and strength are reduced
Solution Approach 1:
The patent introduces a tapered interface as an intermediary mechanism between the screw and motor shaft. This intermediate geometric feature enables mechanical torque transmission through friction and normal forces, replacing the chemical bonding of adhesives while providing superior strength and repeatability.
4Strength
If permanent attachment methods are used to interface screw to motor, then torque transmission is achieved, but disassembly and component reuse become difficult
Solution Approach 1:
The patent creates a dynamic attachment system where the degree of fixation can be controlled. The tapered interface with threaded retention allows the assembly to transition between a secure locked state for operation and an easily disassembled state for maintenance, enabling component reuse while maintaining strong attachment during use.
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 simplifies the interface between the screw and motor, ensuring precise runout and concentricity, allowing for easy component swapping and reducing assembly time while maintaining superior performance and flexibility.
Implementation Method 1
tightening of the retaining screw into the bore engages the taper end of the screw with the internal taper of the fitting forcing the expansions radially outward
Data Source
AI summary
A linear drive assembly having a linear drive motor having a shaft, the shaft defining a first bore therein extending from the first end of the shaft, the shaft defining a tapering within the first bore, and the shaft defining a second bore therein connected with the first bore and extending to the second end of the shaft; a screw including a tapered end at the first end of the screw, the tapered end configured to substantially mate with the tapering within the bore, and the screw defining a threaded bore extending from the tapered end at least partially along a longitudinal axis of the screw; and a retaining screw having a head portion and a threaded portion, the threaded portion configured to extend through the second bore and mate with a threaded bore of the screw when the screw is mounted within the shaft.