Clutch Cam Disk Actuation Mechanism for Transfer Case
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Solution Overview
Problem
Conventional clutch-controlled transfer cases with a two-stage intermediate gear have limited transmission ratios for actuating friction clutches, which restricts the torque transmission capability and efficiency due to the limited angular range of the selector shaft and the mechanical design of existing actuation mechanisms.
Innovation Solution
A device with a selector shaft, clutch cam disk, and switching cam disk, utilizing scissor levers and cam tracks that allow for increased angular rotation of the clutch cam disk, enabling a higher transmission ratio by distributing the clutch actuation over a larger angle range and optimizing the cam track design for increased deflection, thereby enhancing the mechanical transmission and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional actuation mechanisms with limited angular range are used, then the device complexity is reduced, but the transmission ratio is limited
Solution Approach 1:
The invention extends the actuation from a limited angular range to a full 360-degree rotation of the selector shaft. By utilizing the entire rotational dimension, the cam disk can generate sufficient transmission ratio while maintaining a relatively simple mechanical structure. The cam track is designed to convert the extended rotational motion into effective linear actuation force over the complete rotation cycle.
Solution Approach 2:
The invention employs a dynamic cam track design where the radial position of the cam track varies continuously with the rotation angle. This dynamic geometry allows the mechanism to achieve high transmission ratio at critical points in the rotation cycle while maintaining smooth operation throughout the full 360-degree range, avoiding the need for overly complex static mechanical arrangements.
2Productivity
If the angular range of the selector shaft is increased, then the transmission ratio improves, but the device complexity increases
Solution Approach 1:
The selector shaft serves multiple functions: it actuates the friction clutch, shifts the intermediate gear stages, and controls the overall power distribution. By making the selector shaft a universal control element that performs multiple tasks within its 360-degree rotation, the invention achieves high transmission ratio without adding separate complex actuation mechanisms for each function.
Solution Approach 2:
The invention merges the actuation of multiple components (clutch, gear stages) into a single integrated cam disk system driven by the selector shaft. This consolidation allows the mechanism to achieve high transmission ratio through coordinated motion of multiple elements rather than through complex individual actuation systems, thereby improving productivity while controlling device complexity.
3Force
If a higher transmission ratio is achieved through extended angular rotation, then the torque transmission capability improves, but the power requirements for the drive increase
Solution Approach 1:
The invention utilizes the periodic 360-degree rotation of the selector shaft to achieve clutch actuation. The cam track is designed so that the necessary actuation force is generated during specific portions of the rotation cycle, allowing the drive system to operate at lower average power while still achieving the required peak torque transmission capability through the mechanical advantage of the cam mechanism.
Solution Approach 2:
The cam track geometry is designed to generate the necessary actuation force in advance of the actual clutch engagement point in the rotation cycle. This preliminary action allows the mechanical system to build up the required force through the cam's mechanical advantage before the clutch plates need to be pressed together, reducing the instantaneous power requirements of the drive motor.
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
The solution achieves a higher transmission ratio, improving the mechanical efficiency and reducing the power requirements for the drive, allowing for increased torque transmission while maintaining a compact design, thus overcoming the limitations of existing systems.
Implementation Method 1
at least one scissor-type lever (5) whose end (6) is guided in a link (7) provided on the clutch cam disk (3)
Implementation Method 2
The link (7) has a cam track (71, 72) for each scissor-type lever (5), in which the end (6) of the scissor-type lever (5) assigned to the cam track (71, 72) is guided
Data Source
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AI summary
A device for actuating a clutch-controlled transfer case including a rotatable selector shaft, a clutch cam disk rotatable about a clutch cam disk axis by means of the selector shaft and having a gate, and at least one scissor lever having an end guided in the gate. The gate has at least one curved portion having a continuously increasing radial distance from the clutch cam disk axis. The clutch cam disk defines an opening about the clutch cam disc axis, and the clutch cam disk defines a pair of stops extending radially into the opening. The selector shaft is rotatably positioned in the opening. The selector shaft includes a stopping member in radial alignment with the pair of stops such that the selector shaft can be rotated with respect to the clutch cam disk between two stops.