Gearbox Interlocking Key for Oblique Shift Precision
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Solution Overview
Problem
Conventional mechanical gearboxes for vehicles face complexity and cost issues due to numerous moving parts and precise machining requirements, particularly in the assembly and operation of balling systems, which affect the driver's handling experience during gear changes, especially in 'oblique passages'.
Innovation Solution
An internal control device for mechanical gearboxes with a reduced number of ballings, featuring an interlocking key with a double 'V' profile and chamfers, allowing limited translational movement along the longitudinal axis to facilitate angled passages and improve gear change precision, eliminating the need for specific balling at each fork and simplifying the gearbox design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple ballings are provided for each fork and interlocking key, then the positioning precision and holding of moving parts is improved, but the device complexity and assembly cost increase
Solution Approach 1:
The patent combines multiple ballings into a single integrated interlocking key structure. The interlocking key integrates the functions of multiple separate ballings by providing a unified mechanism with multiple notches that can engage with different forks simultaneously, thereby reducing the number of separate components while maintaining positioning precision for multiple engagement elements.
Solution Approach 2:
The interlocking key serves multiple functions: it positions multiple engagement elements simultaneously, prevents simultaneous engagement of multiple reports, and provides a unified indexing mechanism. This multi-functional design replaces what would traditionally require multiple separate ballings, reducing device complexity while maintaining positioning precision.
2Reliability
If multiple ballings with precise machining are provided, then the holding in position of moving parts is improved, but the assembly cost increases
Solution Approach 1:
By merging multiple ballings into a single interlocking key assembly, the patent reduces the number of precision machining operations and assembly steps required. The unified structure can be manufactured as a single component or pre-assembled unit, reducing cumulative tolerance stacking and assembly complexity, thereby lowering manufacturing costs while maintaining reliable positioning.
3Measurement precision
If traditional balling system is used, then the indexing of rotational movement is achieved, but the handling experience during oblique passages deteriorates
Solution Approach 1:
The interlocking key is designed to be movable in translation along the longitudinal axis, providing dynamic adjustment capability. This translational movement allows the key to adapt to different engagement positions and oblique passages, enabling smoother gear changes while maintaining indexing precision through the notching mechanism.
Solution Approach 2:
The movable interlocking key acts as an intermediary between the selection rod and the engagement elements. Its ability to translate along the longitudinal axis provides a mechanical buffer that facilitates oblique passages by allowing sequential engagement, thereby improving handling experience while maintaining precise indexing through its notched structure.
Data Source
Figure 1~3
Figure 4~5
AI summary
The device has an interlocking key (22) carried by a selecting rod (12). A gear change pin (14) and the key are engaged in respective notches arranged in a crosshead (18) integrated to a fork (16) of a casing (24) to immobilize the elements. The pin and the key drive the element by translation of the pin and a finger, respectively, along the rod. The key is movable in translation along a longitudinal axis (XX'), and two fixed stops with respect to the case limits each side of the course of the key at a value less than displacement of the pin during a gear shift engagement.