In-Wheel Transmission Layout With Nested Decelerators for Compact Width
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Solution Overview
Problem
Indirect driving-type in-wheel systems face limitations in achieving large speed reduction ratios due to the volume occupied by decelerators, which increases the size of the system, especially when multiple decelerators are used.
Innovation Solution
A power transmission device with two decelerators, where the first decelerator is inserted into the rotary shaft and coupled thereto, and the second decelerator is coupled to the first decelerator, featuring planetary gears and helical gear regions with opposite helix angles to minimize space and enhance sealability and modularization, allowing for efficient speed reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple decelerators are provided to achieve a large speed reduction ratio, then the speed reduction ratio increases, but the size of the in-wheel system in the width direction becomes excessively increased
Solution Approach 1:
The first decelerator is inserted into the rotary shaft of the motor, and the second decelerator is coupled to the first decelerator, creating a nested configuration where decelerators are arranged axially rather than radially. This nesting approach allows multiple decelerators to be stacked along the axial direction, minimizing the width direction dimensions while achieving the required speed reduction ratio.
Solution Approach 2:
The invention transitions from a radial arrangement of decelerators (which increases width) to an axial arrangement by inserting the first decelerator into the rotary shaft and coupling the second decelerator to the first decelerator. This dimensional reorganization places components along the axial dimension instead of the radial dimension, effectively reducing the width direction footprint.
2Volume of stationary object
If the volume occupied by decelerators is reduced, then the size of the in-wheel system decreases, but the speed reduction ratio that can be achieved is limited
Solution Approach 1:
By nesting the first decelerator inside the rotary shaft and coupling the second decelerator to the first decelerator, the invention achieves a compact volumetric arrangement. This nested configuration maximizes the utilization of available space within the motor housing, allowing two complete decelerator stages to be accommodated in a reduced volume while maintaining the required speed reduction ratio.
Solution Approach 2:
The speed reduction function is segmented into two separate decelerators (first and second), each with its own planetary gear mechanism. This segmentation allows the total speed reduction ratio to be distributed across multiple stages, with each stage contributing to the overall reduction while occupying less individual volume than a single large decelerator would require.
3Area of stationary object
If decelerators are arranged to minimize width direction size, then the in-wheel system becomes more compact, but assembly and sealing become more difficult
Solution Approach 1:
The nested configuration of inserting the first decelerator into the rotary shaft and coupling the second decelerator to the first provides a clear hierarchical assembly sequence. This nesting approach, combined with the modular design of the planetary gear mechanisms, facilitates systematic assembly while maintaining effective sealing paths between the motor and decelerator components.
Data Source
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AI summary
A power transmission device include a motor including a rotary shaft, a first decelerator, coupled to the rotary shaft of the motor, configured to receive power from the rotary shaft, a second decelerator, coupled to the first decelerator, configured to receive the power from the first decelerator, and a wheel bearing coupled to one side of the second decelerator. A portion of the first decelerator is configured to insert into the rotary shaft and couple thereto.