Transfer Case Actuator Mechanism for Drive Ratio Selection
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Solution Overview
Problem
Current transfer cases require separate actuators to select drive ratios and selectively engage secondary output shafts, leading to increased complexity and cost.
Innovation Solution
A transfer case design with a single actuator that uses a gear reduction mechanism and a secondary torque transfer mechanism, operated by a motor-driven gear assembly, to select drive ratios and engage the secondary output shaft, simplifying the actuation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate actuators are used for drive ratio selection and secondary output shaft engagement, then the transfer case can perform both functions, but the device complexity and cost increase
Solution Approach 1:
The patent combines two separate actuators into a single integrated actuator that performs both drive ratio selection and secondary output shaft engagement. The single actuator includes a motor, gear assembly, and linkage mechanisms that sequentially operate the range selector mechanism (for drive ratio) and the clutch mechanism (for secondary output shaft engagement), thereby reducing component count and system complexity while maintaining full functional capability
Solution Approach 2:
The single actuator is designed as a multi-functional device that can perform multiple operations: selecting between first and second drive ratios via the range selector mechanism, and selectively engaging the secondary output shaft via the clutch mechanism. This universal actuator replaces two specialized actuators, achieving the same versatility with reduced complexity
2Adaptability or versatility
If separate actuators are used for drive ratio selection and secondary output shaft engagement, then both functions can be performed independently, but the cost increases
Solution Approach 1:
By merging two separate actuator systems into one integrated unit, the patent reduces the total number of motors, control systems, and mechanical components required. This consolidation lowers manufacturing costs through reduced part counts, simplified assembly processes, and decreased material requirements, while the actuator maintains the capability to perform both drive ratio selection and secondary output shaft engagement
3Device complexity
If a single actuator is used for both drive ratio selection and secondary torque transfer, then complexity and cost are reduced, but the actuator must perform multiple functions sequentially
Solution Approach 1:
The single actuator is designed to perform preliminary actions in a predetermined sequence: first operating the range selector mechanism to establish the desired drive ratio, then subsequently engaging the clutch mechanism to connect the secondary output shaft. This sequential operation is automatically controlled by the actuator's internal timing and linkage design, eliminating the need for complex external control logic and simplifying the overall operation
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 design reduces complexity and cost by integrating the actuation of drive ratio selection and secondary torque transfer into a single actuator system, enhancing operational efficiency and reliability.
Implementation Method 1
The motor may be an electric motor configured to rotate the drive gear assembly
Implementation Method 2
The gear reduction mechanism may include a set of planetary gears
Implementation Method 3
The secondary torque transfer mechanism may include a friction clutch
Data Source
AI summary
A transfer case includes an input shaft, a primary output shaft, a secondary output shaft, and an actuator. The primary output shaft is coupled to the input shaft with a gear reduction mechanism. The secondary output shaft is selectively coupleable to the primary output shaft with a secondary torque transfer mechanism. The actuator includes a first actuation mechanism, a second actuation mechanism, and a driver gear assembly. The first actuation mechanism is configured to operate the gear reduction mechanism. The second actuation mechanism is configured to operate the secondary torque transfer mechanism. The drive gear assembly includes a gear plate member, a sense plate member configured to engage the first actuation mechanism, and a hub member configured to engage the second actuation. The sense plate member and the hub member are independently coupled to the gear plate member to rotate in unison with the gear plate member.