Transfer Case Actuator Mechanism with Face Cam
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Solution Overview
Problem
Current transfer cases require multiple actuators to select drive ratios and selectively engage secondary output shafts, which complicates the drivetrain system and increases complexity.
Innovation Solution
A transfer case with a single actuator that utilizes a hub member, cam mechanism, and bearing member to both select drive ratios and engage the secondary output shaft, incorporating a face cam mechanism to operate the secondary torque transfer mechanism, allowing for a single actuator to manage both functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple actuators are used to select drive ratios and engage secondary output shafts, then the transfer case can perform both functions, but the drivetrain system complexity increases
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 actuator member includes a hub member with bearing members that engage followers on different cam mechanisms, allowing one actuator to control multiple functions through shared mechanical components.
Solution Approach 2:
The single actuator is designed with universal functionality to perform multiple tasks: it selects between high and low drive ratios while also engaging and disengaging the secondary output shaft. The actuator member's design with multiple bearing members allows it to interface with different cam mechanisms for different functions, making it a multi-functional component.
2Device complexity
If a single actuator is used to manage both drive ratio selection and secondary output shaft engagement, then the drivetrain system is simplified, but the actuator must handle increased mechanical stress and force distribution requirements
Solution Approach 1:
The actuator member is segmented into distinct functional components: a hub member with multiple bearing members positioned at different locations. Each bearing member handles specific force requirements for different functions, allowing the actuator to manage distributed mechanical stresses without requiring the entire structure to be overly robust.
Solution Approach 2:
The bearing members act as intermediaries between the actuator's rotational motion and the cam mechanisms. They distribute localized forces from the cam followers across larger surface areas of the hub member, reducing stress concentrations and protecting the actuator structure from excessive mechanical loads.
3Strength
If the bearing member is formed from a harder material than the hub member, then localized force from the follower is distributed across the end wall, but material compatibility and wear resistance must be optimized
Solution Approach 1:
The bearing member is made from a harder material than the hub member to provide localized wear resistance and strength at the contact point with the cam follower. This local quality enhancement allows the bearing member to handle high-contact-stress areas while the rest of the actuator can use softer, more ductile materials that are easier to manufacture and less prone to brittleness.
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
Simplifies the drivetrain system by reducing the number of actuators needed, enhancing operational efficiency and reliability by using a single actuator to manage drive ratio selection and secondary output shaft engagement.
Implementation Method 1
The bearing member is configured to distribute localized force from the follower across the end wall
Implementation Method 2
The face cam mechanism includes a first cam member, a second cam member, and a follower member coupled to the second cam member. The second cam member is configured to displace axially away from the first cam member when rotated relative to the first cam member.
Data Source
AI summary
An actuator for a transfer case includes an actuator member, a face cam mechanism, and a motor. The actuator member includes a circumferential flange and an annular body extending from an inner periphery of the circumferential flange. The annular body includes a circumferential slot opposite the flange defined between two end walls formed by the annular body. One of the end walls includes a bearing member coupled thereto. The face cam mechanism includes a follower coupled to a cam member. The cam member is configured to displace axially when rotated. The follower is disposed within the slot. In a first range of motion, the annular member is rotated independent of the face cam mechanism. In a second range of motion, the bearing member engages the follower to rotate the second cam member relative to the first cam member, and the follower moves axially along the bearing member.