Forkless Synchronizer Sensor Rail Arrangement
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Solution Overview
Problem
Conventional synchronizer assemblies in work vehicles are complex, heavy, and space-consuming due to the use of shift forks and rails, and they face manufacturing and operational challenges such as mechanical failure and increased complexity when using hydraulic power for actuation.
Innovation Solution
A forkless synchronizer arrangement that utilizes rails for positioning sensing and control, eliminating the need for load-carrying rails and reducing the part count and space requirements, while using hydraulic power to disengage and engage shift collars with gears through a sensor rail arrangement and electro-hydraulic system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional shift forks and rails are used in synchronizer assemblies, then the mechanism can reliably engage and disengage gears, but the assembly becomes complex, heavy, and space-consuming
Solution Approach 1:
The patent removes the shift fork from the synchronizer assembly, extracting the load-carrying function to a separate hydraulic actuator. This eliminates the complex mechanical linkage between the shift collar and shift rail, reducing overall assembly complexity while maintaining gear engagement reliability through direct hydraulic actuation of the shift collar.
Solution Approach 2:
The patent replaces the mechanical shift fork-rail system with a hydraulic actuation system. The hydraulic piston directly moves the shift collar axially to engage or disengage gears, eliminating the need for mechanical shift forks and their associated rails, thereby reducing device complexity and weight.
2Extent of automation
If hydraulic power is used to actuate the shift fork, then automated gear shifting is achieved, but the system becomes more complex and prone to mechanical failure
Solution Approach 1:
The patent extracts the hydraulic actuation function from the traditional shift fork mechanism and applies it directly to the shift collar. This eliminates the intermediate mechanical components (shift fork, shift rail) that connected the hydraulic system to the gear engagement function, reducing system complexity while maintaining automation.
Solution Approach 2:
The patent introduces a sensor rail arrangement as an intermediary between the shift collar and the control system. This sensor rail detects the axial position of the shift collar and provides feedback signals, enabling automated control without requiring complex mechanical linkages, thus achieving automation with reduced complexity.
3Ease of operation
If load-carrying rails are used in the synchronizer assembly, then the shift fork can be properly positioned and actuated, but the assembly weight and space requirements increase
Solution Approach 1:
The patent removes the load-carrying function from the rails, converting them into non-load-bearing sensor rails that only detect shift collar position. This extraction of the load-carrying function eliminates the need for heavy, robust rails, significantly reducing assembly weight while still providing adequate shift collar positioning through the sensor feedback mechanism.
Solution Approach 2:
The patent replaces the mechanical load-carrying rail system with a sensor-based detection system. The sensor rail uses non-contact or minimal-contact sensing to detect shift collar position, eliminating the need for heavy mechanical rails that must support shifting loads, thereby reducing weight while maintaining operational capability.
4Adaptability or versatility
If multiple rails and shift forks are used for multiple gears, then each gear can be independently controlled, but the assembly becomes even more complex and space-consuming
Solution Approach 1:
The patent implements a universal sensor rail arrangement where a single sensor rail can detect the axial positions of multiple shift collars corresponding to different gears. This multi-functional approach allows independent control of multiple gears without requiring separate dedicated rails for each gear, significantly reducing assembly volume while maintaining full multi-gear control capability.
Solution Approach 2:
The patent merges the positioning and sensing functions into a single integrated sensor rail system that serves multiple gears simultaneously. Instead of having separate rails for each gear, the sensor rail detects positions of multiple shift collars through a unified structure, reducing the overall volume and complexity of the synchronizer assembly while preserving independent gear control.
Data Source
AI summary
A forkless synchronizer arrangement selectively couples one or more gears to a drive shaft that is rotatable about a rotation axis. A shift collar, rotated by the drive shaft, is configured to disengage from a first of the gears when in a first neutral axial position and to engage the first gear when in a first engaged axial position to transmit rotational input from the drive shaft to the first gear. A rail is arranged in parallel with the rotation axis. A rail arm has an end fixedly coupled to the rail and another end coupled to the shift collar to permit relative rotation and to transmit axial shifting movement to the rail in response to axial movement of the shift collar between the first engaged and neutral axial positions. A sensor proximate the rail senses an axial position of the rail.