Coaxial Shift Drum Mechanism for Compact Power Transmission
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Solution Overview
Problem
Existing shift mechanisms for power transmission devices have a large radial dimension due to the separate axis configuration of the shift drum, which limits their compactness and efficiency.
Innovation Solution
A shift mechanism with concentrically arranged transmission shafts and a pivotable drive drum that uses cam grooves and pins to control the movement of driven drums, allowing for the connection and disconnection of transmission shafts along a common rotational axis, thereby reducing the radial dimension and enhancing compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the shift drum is located on an axis different from the transmission shafts, then the shift mechanism can function properly, but the radial dimension becomes large
Solution Approach 1:
The drive drum is merged with the transmission shafts by positioning it coaxially on the same rotational axis, combining the drive mechanism with the power transmission path rather than separating them on different axes. This eliminates the need for a separate offset axis and reduces radial dimension.
Solution Approach 2:
The invention transitions from a separate-axis configuration to a coaxial configuration, changing the spatial arrangement from radial separation to axial alignment. The driven drums are positioned on the same axis as the transmission shafts, utilizing the axial dimension more effectively to reduce radial footprint.
2Area of stationary object
If multiple transmission shafts are arranged concentrically on a common rotational axis, then the radial dimension is reduced, but the complexity of connecting and disconnecting these shafts increases
Solution Approach 1:
Driven drums are introduced as intermediary elements between the drive drum and the transmission shafts. These driven drums translate the rotational motion of the drive drum into axial movement of the shift sleeves through cam groove mechanisms, simplifying the connection and disconnection process.
Solution Approach 2:
The complex direct mechanical connection system is replaced with a cam groove and pin mechanism. The cam grooves on the driven drums interact with pins on the shift sleeves to convert rotational motion into controlled axial movement, replacing what would otherwise require complex direct coupling mechanisms.
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 enables a more compact and efficient shift mechanism with reduced radial dimensions, allowing for improved power transmission path switching without increasing the device's size, thus enhancing its operational efficiency.
Implementation Method 1
one of the facing surfaces of the drive drum and the first driven drum is provided with a cam groove, and the other one of the surfaces is provided with a pin to be engaged with the cam groove. When the drive drum pivots, the cam grooves and the pins move relatively according to the profiles of the cam grooves, and this causes the first and second driven drums to move along the rotational axis direction.
Data Source
AI summary
A shift mechanism switches power transmission paths among a first transmission shaft, a second transmission shaft, and a third transmission shaft that are concentrically arranged on a rotational axis. The shift mechanism has a drive drum that is provided so as to be coaxial with the rotational axis and pivotable about the rotational axis, and a first driven drum and a second driven drum that are arranged on the rotational axis so as to be concentric with the drive drum and move along the rotational axis as the drive drum pivots. As the first driven drum moves, a first shift sleeve advances and retreats, and the first transmission shaft and the second transmission shaft are connected and disconnected. In addition, as the second driven drum moves, a second shift sleeve advances and retreats, and the second transmission shaft and the third transmission shaft are connected and disconnected.