Integral Input Shaft for Motor and Gearbox Axial Size Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current motor and gearbox shaft connections in electric vehicles are complex, leading to increased axial size and weight, and lack concentricity, affecting system stability.
Innovation Solution
An integral input shaft structure is designed with a main shaft connected to both the motor and gearbox, featuring bearings for axial positioning and a hub with a matching inner bore for radial positioning, ensuring concentricity and stability, and using a bushing and snap ring or tighten nut for secure fit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the motor shaft and gearbox input shaft are connected via splined connection, then the torque transmission is achieved, but the axial size and weight increase
Solution Approach 1:
The patent merges the motor shaft and gearbox input shaft into a single integrated input shaft structure. The motor rotor is directly coupled to the input shaft, eliminating the need for separate splined connection components. This integration reduces the axial dimension by combining what were previously separate transmitting elements into one unified structure, while maintaining full torque transmission capability through direct mechanical coupling.
2Ease of manufacture
If the gear and main shaft are connected by flat key with clearance fit, then the assembly is easy to manufacture, but the concentricity cannot be ensured
Solution Approach 1:
The patent introduces a precisely fitted hub as an intermediary component between the driving gear and the input shaft. The hub features an inner bore that matches the shaft diameter, creating a natural radial positioning mechanism. This intermediary structure provides both radial and axial positioning, ensuring concentricity while maintaining ease of assembly through standardized fitting methods.
3Manufacturing precision
If the shaft and hub are fixed using tapered bushing on one side, then the concentricity is improved, but the structure complexity increases
Solution Approach 1:
The patent segments the positioning function into two independent components: radial positioning is achieved through the precisely fitted hub inner bore matching the shaft diameter, while axial positioning is achieved through the bushing and snap ring or tighten nut arrangement. This segmentation allows each component to perform its specific function optimally without requiring complex integrated solutions like tapered bushings, thereby reducing overall structural complexity.
Data Source
Figure 1~2
Figure 3
AI summary
An input shaft structure for connecting a motor (4) and a gearbox (1) is provided, wherein the input shaft structure comprises a main shaft (5), an input end of the main shaft is located within the motor, and is connected to a rotor of the motor, an output end of the main shaft is located within the gearbox, and is connected to a driving gear (2) of the gearbox, and all of the two ends and an middle portion of the main shaft are provided with a bearing (6, 9, 14) to perform axial positioning, wherein a hub (2-1) of the driving gear extend toward two sides, and an inner bore of the hub matches with a shaft diameter of the main shaft to perform radial positioning, to ensure a concentricity of the driving gear and the main shaft. The motor shaft and the input shaft of the gearbox are designed as an integral input shaft, which reduces the entire axial size of the power section, facilitates the layout of the entire vehicle, and has a smaller weight. The two ends of the driving gear are added radial positioning, to ensure a concentricity of the driving gear and the main shaft, which improves the stability of the system.