Multi-part Pin Shifting Mechanism for Reduced Torque
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Solution Overview
Problem
Existing gearbox shifting mechanisms require excessive torque to implement gear ratio changes due to friction between pins and slots, leading to potential jamming issues, especially when steep angles are used.
Innovation Solution
A shifting apparatus featuring a multi-part pin with first and second parts that rotate relative to each other, extending through slots and channels on a shaft, along with a biasing mechanism and a drive member selector, allowing for reduced friction by enabling the pin to ride along the shaft and rotate in opposite directions, thereby reducing the torque required for gear shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single solid pin is used in the shifting mechanism, then the structure is simple, but excessive torque is required to rotate the shift shaft due to friction between the pin and slot edges
Solution Approach 1:
The pin is divided into two separate parts (first pin part and second pin part) that can rotate relative to each other. This segmentation allows each pin part to independently rotate within its respective slot, reducing friction between the pin and slot edges during drum movement along the shaft. The relative rotation capability eliminates the jamming issue that occurs with a single solid pin when steep ramp angles are used.
2Productivity
If a steep angle on the ramp is used to enable gear ratio changes, then the shifting mechanism can implement gear changes without disengaging the clutch, but the mechanism can jam due to increased friction between pins and slot edges
Solution Approach 1:
The pin structure is made dynamic by allowing the first and second pin parts to rotate relative to each other during operation. This dynamic capability enables the pin to adapt its orientation during drum movement, maintaining smooth operation even with steep ramp angles. The relative rotation prevents the pin from binding against the slot edges, eliminating the jamming risk while preserving the ability to implement gear ratio changes without clutch disengagement.
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 reduces the torque needed for gear ratio shifts, minimizes the risk of jamming, and allows for smoother operation by distributing load effectively across multiple dog features, enhancing gearbox performance and passenger comfort.
Implementation Method 1
a multi-part pin having first and second parts arranged to rotate relative to each other that extend through respective slots extending along the shaft... as the drum moves along the shaft each of the first and second parts of the multi-part pin are in shear with an edge of the slot through which the respective part extends
Implementation Method 2
a biasing mechanism for urging the drum towards a rest position along the length of the shaft... when torque is transferred to the drum from the shaft and an axial force is applied to the drum that overcomes the biasing mechanism the drum moves along the shaft
Data Source
AI summary
A shifting apparatus including a shaft extending along an axis, and at least one shifting feature, each of the at least one shifting feature including: a multi-part pin having first and second parts arranged to rotate relative to each other that extend through respective slots extending along the shaft; a drum arranged around the shaft and having channels extending along the length thereof wherein the first and second parts of the multi-part pin are respectively received for enabling torque transfer to the drum when the shaft is rotated, the drum also defining a track at least partially around its outer surface; a biasing mechanism for urging the drum towards a rest position along the length of the shaft; and a drive member selector member provided in operative relation to the track. The drive member selector member can be controlled to selectively engage a drive member.