Divided Input Shaft Spline Placement for Power Transmission Assembly
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Solution Overview
Problem
Existing power transmission devices in automobiles face assembly challenges due to interference between components, particularly the first clutch and sun gear of the third planetary gear mechanism, which can lead to reduced assembly efficiency and potential durability issues when subjected to high torque.
Innovation Solution
The power transmission device employs a divided input shaft with coaxially connected first and second input shafts via spline engagement portions, allowing for smooth assembly by separating the components and minimizing torque at critical connections to prevent durability reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the first clutch and sun gear of the third planetary gear mechanism are integrally connected to the input shaft, then the structure is simplified, but assembly becomes difficult due to interference with planetary gear mechanisms
Solution Approach 1:
The input shaft is divided into a first input shaft and a second input shaft that can be separated. The first clutch is connected to the first input shaft, while the sun gear of the third planetary gear mechanism is connected to the second input shaft. This segmentation allows the planetary gear mechanisms to be assembled without interference from the first clutch, while maintaining the integrated structure's simplicity where applicable.
2Productivity
If the input shaft is divided into pieces to enable smooth assembly, then assembly efficiency is improved, but durability is reduced due to high torque at divided portions
Solution Approach 1:
The spline engagement portions are strategically positioned at locations where the torque acting on the input shaft is relatively small. Specifically, the first spline engagement portion connects the first and second input shafts at a position away from the high-torque regions near the first clutch and third clutch. This local optimization ensures that the divided portions experience minimal stress, maintaining durability while enabling efficient assembly.
3Ease of manufacture
If spline engagement portions are used to connect divided input shafts, then assembly is facilitated, but torque transmission may be compromised at connection points
Solution Approach 1:
The design changes the operational parameters of the spline engagement portions by positioning them in regions where the torque load is minimized. The first spline engagement portion connects the input shafts at a location where torque is relatively low compared to the regions near the clutches. This parameter optimization allows the spline connections to adequately transmit torque while facilitating easy assembly and disassembly.
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 solution enables efficient assembly of the power transmission device without component interference and maintains the durability of the input shaft by optimizing the placement of spline engagement portions to reduce torque, thereby enhancing assembly efficiency and durability.
Implementation Method 1
a first spline engagement portion that connects the first input shaft and the second input shaft to each other
Data Source
AI summary
A first clutch, a first planetary gear mechanism, a second planetary gear mechanism, a third planetary gear mechanism, a fourth planetary gear mechanism, and a third clutch are arranged along an input shaft in that order from a driving source. The input shaft includes first and second input shafts that are coaxially connected together through a first spline engagement portion and capable of being separated from each other in an axial direction. The first spline engagement portion is disposed between the first clutch and a first element of the third planetary gear mechanism on the input shaft. The first clutch is connected to the first input shaft. The first element of the third planetary gear mechanism and the third clutch are connected to the second input shaft. The first element of the third planetary gear mechanism is removably connected to the second input shaft through a second spline engagement portion.