Transmission Shift Interlock Mechanism Preventing Simultaneous Gear Engagement
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Solution Overview
Problem
In vehicle and non-vehicle transmissions, there is a risk of accidentally engaging multiple gears simultaneously, which can lead to wear and damage, necessitating a mechanism to prevent simultaneous gear engagement.
Innovation Solution
A shift interlock assembly with a shift rail and interlock passages prevents simultaneous engagement by using interlock members that move between indents on gear engagement devices, ensuring only one gear can be engaged at a time by aligning interlock passages and indents to restrict movement when another gear is engaged.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If multiple gear engagement devices are mounted on a single shift rail to minimize space, then the transmission occupies less space, but the risk of accidentally engaging multiple gears simultaneously increases
Solution Approach 1:
An interlock member is introduced as an intermediary element between the gear engagement devices. This interlock member physically connects multiple engagement devices and prevents them from being simultaneously actuated, thereby resolving the contradiction by maintaining compact spacing while ensuring safe operation
Solution Approach 2:
The interlock mechanism is designed to preemptively prevent simultaneous gear engagement before it can occur. The interlock member is positioned and configured to block the movement of engagement devices in advance, eliminating the risk of accidental multi-gear engagement before it happens
2Reliability
If an interlock mechanism is added to prevent simultaneous gear engagement, then gear engagement safety is improved, but the device complexity increases
Solution Approach 1:
The interlock function is merged with the existing shift rail structure. The interlock passage is formed within the shift rail itself, and the interlock member integrates with the gear engagement devices through shared components like the interlock portions and indents, thereby reducing overall complexity compared to a separate interlock system
Solution Approach 2:
The shift rail serves multiple functions: it guides the movement of gear engagement devices, provides structural support, and incorporates the interlock passage to enable the interlocking function. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity
Data Source
AI summary
A transmission interlock assembly is described. A shift rail may include an interlock passage containing at least one interlock member. First and second gear engagement devices mounted to the shift rail may include, respectively, first and second interlock indents. The interlock member may extend into the first or the second interlock indent when, respectively, the first or the second gear engagement device is in neutral. With both gear engagement devices in neutral, as the first (or second) gear engagement device is moved to engage a gear, the interlock member may be urged out of the first (or second) indent and into the second (or first) indent, the interlock member thereby preventing the second (or first) gear engagement device from moving out of neutral.