Gearbox Selection Mask for Silent Reverse Gear Engagement
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Solution Overview
Problem
Existing motor vehicle gearboxes face difficulties in engaging reverse gear due to residual rotation of the primary shaft, leading to squealing noises and requiring complex braking solutions that increase costs and complicate the gearbox layout.
Innovation Solution
A device with a guide mechanism that temporarily rotates the selection mask to engage the forward gears, causing the primary shaft to stop rotating, allowing for silent and regular engagement of the reverse gear, by shaping the guide means to ensure the selection mask moves into a rotated position during axial travel, activating the forward gear actuation elements to brake the primary shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the primary shaft continues to rotate due to inertia during reverse gear engagement, then the residual rotation must be braked using complex braking solutions, but this increases device complexity and manufacturing costs
Solution Approach 1:
The guide means for the selection mask is designed to preliminarily rotate the selection mask into a position that actuates the forward gear actuating elements before the reverse gear engagement is completed. This preliminary action brakes the primary shaft rotation in advance, eliminating the need for complex dedicated braking mechanisms and allowing smooth reverse gear engagement.
2Ease of operation
If the primary shaft has residual rotation speed during reverse engagement, then braking mechanisms are required to stop the rotation, but this increases manufacturing costs and complicates the gearbox layout
Solution Approach 1:
The guide means for the selection mask serves multiple functions: it guides the selection mask during normal operation and simultaneously acts as a braking mechanism by rotating the selection mask to engage forward gear actuating elements. This multi-functionality eliminates the need for separate braking components, reducing manufacturing complexity and costs while ensuring smooth reverse gear engagement.
3Reliability
If complex braking solutions are implemented to stop primary shaft rotation, then reverse gear engagement reliability improves, but the gearbox layout and component configuration become more complex
Solution Approach 1:
The guide means for the selection mask utilizes the existing selection mask mechanism and forward gear actuating elements to brake the primary shaft rotation. The system serves itself by using its own components in a dual capacity, eliminating the need for external or additional braking components and maintaining a simple gearbox layout while ensuring reliable reverse gear meshing.
Data Source
AI summary
A device for selection and engagement of the gears of a gearbox for motor vehicles has a control shaft mounted rotatable and axially movable with respect to the casing. Mounted on the shaft is a hub having an engagement finger for controlling gear engagement devices, which is configured to oscillate in the space between two fingers of a selection mask, which is mounted on the shaft axially movable therewith and is guided with respect to the casing so as not to follow rotation of the shaft and the hub when a gear is engaged. During displacement of the engagement finger towards an extreme position preliminary to the engagement of the reverse gear, the selection mask is forced to move temporarily into a rotated position, wherein it actuates one or more of the selector devices of the forward gears to enable silent engagement of the reverse gear.