Knurled Pin Coupling for Plastic Pedal Rotor and Shaft
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Solution Overview
Problem
Existing rotor-to-shaft coupling structures in vehicle pedal assemblies are not applicable when both components are made of the same or similar materials, such as plastic, as they lack a secure and cost-effective method for attachment.
Innovation Solution
A pin coupling assembly is used, where a pin with a knurled outer surface is interference fitted through a recess in the shaft and a through aperture in the rotor, with beveled ends for easy alignment and a collar for retention, providing a secure and inexpensive coupling between a plastic rotor and shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If press fitting or slot-based coupling is used for rotor to shaft attachment, then the coupling works for metal shafts, but it cannot be applied when both shaft and rotor are made of plastic
Solution Approach 1:
A pin is introduced as an intermediary component to couple the rotor to the shaft. The pin includes a metal core with a knurled outer surface that provides secure interference fitting into both the shaft and rotor, enabling reliable attachment when both components are made of plastic materials that cannot be directly coupled using traditional metal shaft methods
2Reliability
If a pin with knurled surface is interference fitted through rotor and shaft, then secure attachment is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The pin design incorporates a knurled outer surface that changes the friction parameters between the pin and the holes in the rotor and shaft. This increased friction from the knurled surface allows for secure interference fitting with reduced sensitivity to dimensional variations, thereby reducing the number of dimensions that must be tightly controlled during manufacturing
3Ease of operation
If beveled ends are added to the pin for alignment, then ease of assembly improves, but device complexity increases
Solution Approach 1:
The pin is pre-formed with beveled ends during manufacturing. These beveled ends automatically guide the pin into proper alignment with the rotor and shaft holes during assembly, eliminating the need for separate alignment operations and simplifying the assembly process despite the slightly more complex pin structure
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 solution enables a robust, simple, and cost-effective coupling of a plastic rotor to a plastic shaft, ensuring secure attachment and alignment while reducing the number of dimensions to control, thus addressing the limitations of existing coupling methods.
Implementation Method 1
the pin includes a knurled outer surface and is interference fitted to the rotor and the shaft
Data Source
AI summary
An assembly for coupling the rotor of a vehicle pedal assembly to the shaft of a vehicle pedal assembly. The rotor includes a cap which is fitted over a distal end of the shaft. The cap and the distal end of the shaft define a through aperture and an interior recess respectively. A coupling pin extends through the aperture in the cap of the rotor and into the recess in the shaft and includes a knurled outer surface which allows the pin to be interference fitted to the rotor and the shaft for securely coupling the rotor to the shaft.