Concentric 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
1Ease of operation
If the shift drum is located on an axis different from the transmission shafts, then the power transmission paths can be switched effectively, but the radial dimension becomes large
Solution Approach 1:
The invention merges the drive drum axis with the transmission shafts by arranging them concentrically on a common rotational axis. This integration eliminates the need for a separate parallel axis configuration, thereby reducing the radial dimension while maintaining the power transmission path switching function through the concentric arrangement of the drive drum (130) and transmission shafts (110, 120, 140).
Solution Approach 2:
The invention transitions from a parallel axis configuration to a concentric arrangement, effectively changing the spatial dimension from radial separation to axial stacking. The drive drum and transmission shafts are arranged concentrically, allowing the mechanism to achieve compact radial dimensions while utilizing the axial dimension for the movement of shift sleeves and engagement of gears.
2Volume of moving object
If the transmission shafts are arranged concentrically on a common rotational axis, then the radial dimension is reduced, but the complexity of controlling multiple shift sleeves increases
Solution Approach 1:
The drive drum serves multiple functions: it drives both the first driven drum (150) and second driven drum (160) through its circumferential surface, and its rotation simultaneously controls both shift sleeves (180, 190). This multi-functionality reduces the need for separate control mechanisms for each shift sleeve, thereby managing complexity while achieving compact radial dimensions.
Solution Approach 2:
The cam grooves (131, 132) on the drive drum act as intermediaries that translate the rotational motion of the drive drum into the axial movement of the driven drums and shift sleeves. This intermediary mechanism simplifies the control of multiple shift sleeves by using a unified cam groove design that can be replicated or varied to achieve different shifting sequences.
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 and versatility.
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.