Concentric Actuation Transfer Case Barrel Cam Design
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Solution Overview
Problem
Current transfer cases require a plethora of off-axis components to actuate both the range shifting assembly and the clutch assembly, making them complex and costly to produce.
Innovation Solution
A motor-driven transfer case with concentric actuation that uses a simplified off-axis gear train to rotate a gear mounted concentric to the clutch and range actuating axis, with a barrel cam and springs to actuate both the range shifting and clutch functions, reducing the number of components needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate power-operated actuators are used to control the range shift mechanism and clutch assembly, then each component can be independently controlled, but the device complexity and production cost increase
Solution Approach 1:
The patent combines the control of the range shift mechanism and clutch assembly into a single power-operated actuator. The actuator uses a cam mechanism with different cam lobes that sequentially engage with shift forks to perform both range shifting and clutch actuation functions, thereby reducing the number of actuators from two to one while maintaining independent control capability through programmed sequential operation
Solution Approach 2:
The single power-operated actuator is designed with a universal cam mechanism that can perform multiple functions: actuating the range shift mechanism via first and second shift forks, and actuating the clutch assembly via a clutch fork. The cam mechanism is engineered with specific cam lobes that sequentially engage different forks to achieve diverse actuation functions from a single actuator source
2Device complexity
If a single motor is used to perform both clutch actuating and range shifting functions, then component quantity is reduced, but additional off-axis components such as worm gear drives, cams, barrel cams, gear reduction, shift shafts, and range forks are required
Solution Approach 1:
The patent merges the functions of multiple off-axis components into a single integrated cam mechanism. The cam mechanism incorporates multiple cam lobes on a single cam shaft that sequentially engage with shift forks and clutch fork, eliminating the need for separate worm gear drives, barrel cams, gear reduction mechanisms, and multiple shift shafts, thereby reducing overall component quantity while maintaining manufacturing feasibility
Solution Approach 2:
The cam mechanism is designed as a universal actuating component that can control both the range shift mechanism and clutch assembly through its multiple cam lobes. The single cam shaft with strategically positioned cam lobes can sequentially actuate different forks, providing multi-functionality without requiring additional specialized components for each function
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances efficiency and reduces component complexity, allowing for effective actuation of both range shifting and clutch functions using fewer components, thereby improving the operational efficiency and reducing production costs.
Implementation Method 1
The range function is performed by rotating a barrel cam, through a plurality of springs. A shift fork can travel within a cam range of the barrel cam for shifting between a low-range and high-range drive mode.
Implementation Method 2
The concentric gear can actuate the range shifting assembly during a portion of angular rotation about the primary axis and can actuate the clutch assembly during a mutually exclusive portion of angular rotation about the primary axis.
Data Source
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AI summary
A transfer case (30) and a method of assembly can include a range shifting assembly (60) and a clutch assembly (80) located axially adjacent to one another along a common primary axis. An actuating device (32) can include a concentric gear located coaxially interposed between the range shifting assembly (60) and the clutch assembly (80) for rotation about the common primary axis. The concentric gear (48) can actuate the range shifting assembly (60) during a portion of angular rotation about the common primary axis and can actuate the clutch assembly (80) during a mutually exclusive portion of angular rotation about the common primary axis. The actuating device (32) can include a barrel cam (59), a plurality of springs engageable between the barrel cam (59) and the concentric gear (48), and a shift fork (68) operably engageable with a cam surface groove (57) for guided axial movement to actuate the range shifting assembly (60) between a low-range and high-range drive mode.