Stepped Pin Gearbox Box Assembly for Scratch-Free Bearing Mounting
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Solution Overview
Problem
Conventional gearbox assemblies with multi-bearing integrated shaft structures face issues of surface scratches during assembly due to insufficient offset room between positioning pins and pin holes, affecting the performance and lifespan of bearings and the entire system.
Innovation Solution
The use of stepped pins with a guide section and an engagement section, where the guide section provides a larger radial gap to prevent scratches during assembly, allowing more than half of the axial length of rollers to enter the raceway before the engagement section secures the first housing, ensuring a sufficient radial space and preventing compression-induced scratches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If single-diameter positioning pins are used to position housings, then the assembly structure is simple, but there is not enough offset room between positioning pins and pin holes, causing rollers and inner ring to compress each other and form surface scratches
Solution Approach 1:
The positioning pin is segmented into two distinct sections: a guide section with a first diameter and an engagement section with a second diameter. This segmentation allows the guide section to provide sufficient offset room during assembly, preventing compression and surface scratches, while the engagement section provides secure positioning. The pin is thus divided into functional zones that address different requirements of the assembly process.
Solution Approach 2:
Different sections of the positioning pin have different diameters to fulfill different local functions. The guide section has a larger diameter (first diameter) to create adequate radial clearance and offset room, preventing harmful compression during assembly. The engagement section has a smaller diameter (second diameter) to provide precise positioning and secure connection. This local variation in geometric quality resolves the contradiction between assembly safety and positioning accuracy.
2Object-affected harmful factors
If positioning pins with sufficient offset room are used, then surface scratches are prevented, but the positioning pin structure becomes more complex
Solution Approach 1:
The positioning pin is segmented into two distinct sections: a guide section with a first diameter and an engagement section with a second diameter. This segmentation allows the guide section to provide sufficient offset room during assembly, preventing compression and surface scratches, while the engagement section provides secure positioning. The pin is thus divided into functional zones that address different requirements of the assembly process.
Solution Approach 2:
Different sections of the positioning pin have different diameters to fulfill different local functions. The guide section has a larger diameter (first diameter) to create adequate radial clearance and offset room, preventing harmful compression during assembly. The engagement section has a smaller diameter (second diameter) to provide precise positioning and secure connection. This local variation in geometric quality resolves the contradiction between assembly safety and positioning accuracy.
3Object-affected harmful factors
If the guide section diameter is increased to prevent scratches, then bearing protection is improved, but the positioning accuracy may be affected
Solution Approach 1:
The positioning pin is segmented into two distinct sections: a guide section with a first diameter and an engagement section with a second diameter. This segmentation allows the guide section to provide sufficient offset room during assembly, preventing compression and surface scratches, while the engagement section provides secure positioning. The pin is thus divided into functional zones that address different requirements of the assembly process.
Solution Approach 2:
Different sections of the positioning pin have different diameters to fulfill different local functions. The guide section has a larger diameter (first diameter) to create adequate radial clearance and offset room, preventing harmful compression during assembly. The engagement section has a smaller diameter (second diameter) to provide precise positioning and secure connection. This local variation in geometric quality resolves the contradiction between assembly safety and positioning accuracy.
Data Source
AI summary
An electric drive power transmission system box assembly is provided having stepped pin positioning and a mounting method of the electric drive power transmission system box assembly. The box assembly includes a housing shaft string assembly, stepped pins, a first housing, and a first bearing. The housing shaft string assembly includes a housing and a shaft string supported on the housing. Each stepped pin includes a matching section and a guide section, the diameter of the matching section is greater than the diameter of the guide section, a tail end portion of the matching section is fixed in a fixing pin hole of the housing, the first housing is mounted and fixed to the housing shaft string assembly under the guide of the guide section, and a rear end of the shaft string is supported on the first housing by means of the first bearing.