Concentric Input Shaft and Ring Gear Transfer Design
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Solution Overview
Problem
Existing four-wheel-drive vehicle transfer systems are bulky due to the separation of rotational axes of the ring gear and input shaft, leading to increased size and complexity.
Innovation Solution
A compact transfer system design where the input shaft is arranged concentrically within the ring gear, with a connecting-disconnecting mechanism that allows for efficient power transmission between the ring gear and input shaft, reducing the overall size by minimizing the distance between their rotational axes and optimizing the assembly of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the rotational axes of the ring gear and input shaft are separated (two-axis configuration), then the power transmission path is simplified, but the size of the transfer in the direction perpendicular to the ring gear rotational axis increases
Solution Approach 1:
The input shaft is arranged concentrically inside the ring gear, with the input shaft passing through the central through-hole of the ring gear. This nesting configuration allows the input shaft to be positioned within the ring gear's rotational axis, minimizing the perpendicular distance between axes and reducing the transfer's overall size in the direction perpendicular to the ring gear axis.
Solution Approach 2:
The design transitions from a two-axis configuration (separated rotational axes) to a concentric single-axis configuration (coincident rotational axes). By changing the spatial arrangement from separated axes to concentric axes, the patent reduces the footprint in the direction perpendicular to the ring gear axis while maintaining power transmission functionality through the axial direction.
2Area of stationary object
If the input shaft is arranged concentrically inside the ring gear, then the transfer size is reduced, but the assembly complexity increases due to the need for precise positioning and integration
Solution Approach 1:
The ring gear is designed with a central through-hole that accommodates the input shaft, creating a nested structure where the input shaft passes through the ring gear's center. This design simplifies assembly by allowing the input shaft to be inserted axially through the ring gear, avoiding complex lateral positioning requirements.
Solution Approach 2:
The transfer is divided into modular components: the ring gear assembly (including the case and bearing), the input shaft assembly (including the clutch mechanism), and the connecting-disconnecting mechanism. This segmentation allows each component to be manufactured and assembled independently, reducing overall assembly complexity.
3Adaptability or versatility
If a connecting-disconnecting mechanism is added to enable 4WD state, then the vehicle can switch between 2WD and 4WD, but the number of components and transfer size increase
Solution Approach 1:
The connecting-disconnecting mechanism serves multiple functions: it connects the input shaft to the ring gear for 4WD operation, disconnects them for 2WD operation, and the sleeve itself acts as both a connecting element and a shifting element. This multi-functionality reduces the need for separate components for each function.
Solution Approach 2:
The sleeve is designed to perform multiple roles simultaneously: it acts as a connecting element that engages the input shaft with the ring gear, a shifting element that moves axially to connect or disconnect power transmission, and a support element that is guided by the case. By merging these functions into a single component, the patent reduces the total number of parts.
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 design reduces the size of the transfer system perpendicular to the ring gear's rotational axis, enhancing compactness and assembly efficiency while maintaining effective power transmission between the main and auxiliary driving wheels.
Implementation Method 1
The input shaft is supported at a first end portion of the input shaft and a second end portion of the input shaft by the case in a manner rotatable around the rotational axis via the first bearing and the second bearing
Implementation Method 2
The case supports the ring gear via the third bearing in a manner enabling the ring gear to rotate around a rotational axis
Data Source
AI summary
A transfer includes a main body, a subassembly and a connecting-disconnecting mechanism. The main body includes a ring gear, a case and a third bearing. The subassembly includes an input shaft, a sleeve, a moving mechanism, a first bearing and a second bearing. The connecting-disconnecting mechanism selectively connects/disconnects the ring gear to/from the input shaft. The input shaft is arranged concentric with the ring gear and inside the ring gear. The input shaft includes a first end portion and a second end portion. The input shaft is supported at the first end portion and the second end portion by the case in a manner rotatable around the rotational axis via the first bearing and the second bearing.