Shared Shift Drum Transmission for Smooth Vehicle Gear Changes
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Solution Overview
Problem
Existing vehicle drive transmission devices have a high number of components due to independent configurations for meshing and frictional engagement devices, leading to increased size and cost.
Innovation Solution
A vehicle drive transmission device with an intermesh first engagement device, a frictional second engagement device, and a shared drive mechanism that integrates the first and second shift drums via a drive shaft, allowing both engagement devices to be driven by a single drum drive source, reducing the number of components and maintaining power transmission during shift speed changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If independent drive devices are provided for meshing engagement device and frictional engagement device, then each engagement device can be driven independently, but the number of components increases leading to increased size and cost
Solution Approach 1:
The patent merges the drive mechanisms for the meshing engagement device and frictional engagement device into a single integrated drive device. This drive device includes a common drive source that can selectively drive either the meshing engagement device or the frictional engagement device through shared transmission components, thereby reducing the total number of components while maintaining the ability to independently control each engagement device when needed
Solution Approach 2:
The integrated drive device is designed with multi-functionality to perform multiple roles: it can drive the meshing engagement device, drive the frictional engagement device, and provide continuous power transmission during shift operations. The drive device includes universal components such as a common drive source and shared transmission path that can serve different engagement devices based on operational requirements
2Adaptability or versatility
If meshing engagement device is disengaged during shift speed change, then shift speed can be changed, but power transmission is interrupted causing shock and fluctuation in wheel driving force
Solution Approach 1:
The frictional engagement device is engaged in advance before the meshing engagement device is disengaged during a shift speed change. This preliminary engagement of the frictional device ensures that power transmission is already established through the frictional connection before the meshing connection is broken, thereby preventing interruption in power transmission and avoiding shock to the wheel driving force
Solution Approach 2:
The frictional engagement device acts as an intermediary during the transition between different shift speeds. When the meshing engagement device is being disengaged, the frictional engagement device provides a continuous power transmission path, serving as a mediator that prevents complete interruption of power flow and smooths the transition between different engagement states
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 configuration reduces the number of components, suppresses size and cost increases, and prevents fluctuations in wheel driving force during shift speed changes by ensuring continuous power transmission.
Implementation Method 1
a frictional second engagement device (2)
Data Source
AI summary
In a vehicle drive transmission device, a transmission includes an intermesh first engagement device, a frictional second engagement device, a first drive device configured to drive the first engagement device, and a second drive device configured to drive the second engagement device. The first drive device includes a first shift drum, a first cam mechanism configured to convert rotational motion of the first shift drum into linear motion, and a first transmission mechanism configured to perform the linear motion. The second drive device includes a second shift drum, a second cam mechanism configured to convert rotational motion of the second shift drum into linear motion, and a second transmission mechanism configured to perform the linear motion. The first shift drum and the second shift drum are connected so as to rotate integrally with each other via a drive shaft. A drum drive source is provided to drive the drive shaft.