Spline Lock Nut Retainment for Precise Torque Positioning
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Solution Overview
Problem
Existing mechanical lock nut retainment systems fail to provide the necessary precision, robustness, and security for heavy-duty equipment while ensuring ease of assembly and disassembly, leading to premature wear or catastrophic failure due to improper torque retention.
Innovation Solution
A mechanical lock nut retainment system comprising a shaft with external threads and splines, a lock nut with internal threads and grooves, and a lock washer with internal splines and teeth, where the teeth of the washer fit into the grooves of the nut, ensuring a unique rotational relationship that fixes the lock nut in a specific position, resisting vibration and impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional locking mechanisms (cotter keys, split pins, lock washers) are used to retain lock nuts, then ease of assembly and disassembly is improved, but precision and security of torque retention deteriorate
Solution Approach 1:
A lock washer with internal splines acts as an intermediary component between the shaft and lock nut. The lock washer engages with both the shaft splines and the lock nut grooves, providing a positive mechanical connection that maintains precise torque retention while enabling straightforward assembly and disassembly operations.
Solution Approach 2:
The locking function is segmented into distinct components: the shaft with external splines, the lock nut with grooves, and the lock washer with internal splines and teeth. This segmentation allows each component to perform its specific function independently, with the lock washer providing both the locking mechanism and the interface for tool engagement during assembly and disassembly.
2Ease of operation
If friction/chemical assisted retainment is used instead of mechanical retainment, then ease of assembly is improved, but reliability and security under harsh conditions deteriorate
Solution Approach 1:
The patent replaces friction-based or chemical retainment systems with a purely mechanical retainment system. The lock washer engages positively with the shaft splines and lock nut grooves through mechanical interlocking, providing reliable security under vibration and impact conditions while maintaining ease of assembly through simple mechanical engagement.
3Ease of operation
If the angle between spaced teeth is evenly divisible by the angle between splines, then ease of assembly is improved, but manufacturing precision and unique rotational positioning deteriorate
Solution Approach 1:
The patent employs asymmetric angular relationships between the spaced teeth on the lock washer and the spaced grooves on the lock nut. By making the angle between teeth not evenly divisible by the angle between grooves, the system ensures a unique rotational positioning when assembled, preventing any ambiguity or multiple possible orientations while still allowing straightforward assembly through the self-aligning nature of the splined connection.
Data Source
AI summary
A mechanical lock nut retainment system enables accurate retention of a specified assembled position and torque of a lock nut. The system includes: a shaft having external threads on a threaded portion and external splines on a splined portion; a lock nut having internal threads that are threaded onto the threaded portion of the shaft, and the nut having spaced grooves extending around a circumference of the nut; and a lock washer having internal splines receivable on the splines of the splined portion of the shaft, and the washer having spaced teeth extending around a circumference of the washer. The spaced teeth of the washer are receivable in the spaced grooves of the nut.