Gearbox Shift Rod Interlock for Reverse Selection Prevention
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Solution Overview
Problem
Current shift control arrangements in gearboxes for vehicles, particularly in heavier vehicles like trucks, face challenges such as inadvertent selection of forward or reverse modes, complexity in assembly and disassembly, high manufacturing and maintenance costs, and a lack of compact design, which can lead to damage and increased weight due to unnecessary components like reverse gear wheels.
Innovation Solution
A shift control arrangement featuring first and second shift rods with specific groove configurations and lock pins that restrict or allow axial movement, preventing inadvertent mode selection, facilitating easy assembly and disassembly, reducing manufacturing and maintenance costs, and incorporating a compact design with reduced axial extension and weight by integrating lock pins in a common guide hole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a reverse gear wheel is added to the main gearbox device, then reverse gear functionality is achieved, but the gearbox length and vehicle weight increase
Solution Approach 1:
The reverse gear functionality is extracted from the main gearbox device and relocated to the range gearbox device. This allows the main gearbox to maintain its compact design while the auxiliary range gearbox provides the reverse gear capability through a separate planetary gear mechanism.
Solution Approach 2:
The range gearbox device is designed to serve multiple functions: it provides both the reverse gear functionality and the range shifting capability (low range/high range). By integrating the reverse gear wheel into the range gearbox, one component performs multiple functions, avoiding the need for separate dedicated reverse gear mechanisms in the main gearbox.
2Adaptability or versatility
If a reverse gear wheel with intermediate gear wheel is added, then reverse gear is achieved, but noise and energy losses increase
Solution Approach 1:
The reverse gear mechanism is extracted from the main gearbox power flow path and placed in the range gearbox. This separation allows the reverse gear to operate through a dedicated planetary gear set with direct engagement, eliminating the need for intermediate gear wheels that cause energy losses and noise in the main transmission path.
3Ease of operation
If multiple axially displaceable coupling sleeves are used for range and reverse gear shifting, then gear positioning is achieved, but assembly and disassembly complexity increases
Solution Approach 1:
The control mechanisms for multiple coupling sleeves are merged into a single integrated shift control arrangement. The shift forks and actuating mechanisms are combined such that one coordinated control system manages both the range gear positioning and reverse gear positioning, simplifying the overall assembly and disassembly process while maintaining precise gear control.
4Ease of operation
If separate guide holes for lock pins are provided for first and second shift rods, then shift control is achieved, but manufacturing costs and device complexity increase
Solution Approach 1:
The guide holes for the lock pins of both the first and second shift rods are merged into a single common guide hole in the gearbox housing. This allows both shift rods to be controlled through one integrated positioning feature, reducing manufacturing complexity and costs while maintaining independent control capability for each shift rod through the shared guide hole structure.
Data Source
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AI summary
The invention relates to a shift control arrangement (3) in a gearbox (2), comprising a first shift rod (68), provided with a first and second end part (72, 82), which first end (72) part is connectable to a first power means (66) and the second end part (82) is connected to a first shift fork (60); a second shift rod (70), provided with a first and second end part (73, 84), which first end part (73) is connectable to a second power means (67) and the second end part (84) is connected to a second shift fork (61); a first set of grooves (86) arranged in the first shift rod (68), a second set of grooves (88) arranged in the second shift rod (70); and a first and a second lock pin (75, 79) arranged between the first and second shift rods (68, 70), which first and a second lock pins (75) together with the first and second set of grooves (86, 88) are arranged to restrict or allow axial movement of the respective first and second shift rod (68, 70). The first set of grooves (86) comprises at least one groove (96, 97) arranged in the first shift rod (68) above a plane (101) passing through the first and second shift rods (68, 70), and at least one groove (98, 99) arranged below the plane (101), and the second set of grooves (88) comprises at least one groove (94) arranged in the second shift rod (70) above the plane (101) and at least one groove (95) arranged below the plane (101).