Planetary Transmission Layout for Stop-Shift Gear Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power transmission devices face challenges in switching from high gear speed to low gear speed when stopped, due to potential skew between spline phases, preventing gear shift position changes.
Innovation Solution
A power transmission device incorporating a planetary gear set, a band brake for low gear speed, and a multi-plate friction clutch for high gear speed, allowing gear shift position switching without requiring spline phase alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a meshing type engagement device is used to switch between high gear speed and low gear speed, then the transmission mechanism can achieve gear shift switching, but when the vehicle is stopped with skew between spline phases, the gear shift position cannot be switched from high gear speed to low gear speed
Solution Approach 1:
The patent replaces the meshing type engagement device (spline coupling) with a friction type engagement device (friction clutch). This substitution eliminates the spline phase alignment requirement, allowing gear shift position switching to be performed reliably even when the vehicle is stopped, without the mechanical interlocking constraints of the original system
Solution Approach 2:
The patent changes the engagement mechanism from rigid mechanical meshing to friction-based engagement. This parameter change in the engagement method allows for flexible switching between gear speeds by controlling friction force, eliminating the constraint of spline phase alignment and enabling reliable switching at stationary conditions
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
Enables seamless switching between high and low gear speeds when the vehicle is stopped, reducing shift shock and friction, and improving energy efficiency by using friction-type engagement elements.
Implementation Method 1
the first engagement element is a band brake that is engaged when the transmission mechanism is in the low gear speed
Implementation Method 2
the second engagement element is a multi-plate friction clutch that is engaged when the transmission mechanism is in the high gear speed
Data Source
AI summary
A power transmission device includes a transmission mechanism including a planetary gear set, a first engagement element, and a second engagement element. The first engagement element is a band brake configured to be engaged when the transmission mechanism is in a low gear speed. The second engagement element is a multi-plate friction clutch configured to be engaged when the transmission mechanism is in a high gear speed. The multi-plate friction clutch includes a driven plate and a drive plate. The band brake overlaps with the driven plate and the drive plate of the multi-plate friction clutch in a radial direction.