Crankcase Pre-Centering Pin Geometry for Misalignment-Free Assembly
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Solution Overview
Problem
The existing assembly methods for motor vehicle powertrains with adjacent electrical machines and transmission mechanisms face challenges in achieving precise axial alignment due to dimensional dispersions, leading to hyperstatic conditions and misalignment, which complicates the centering process and may require manual force that can stress components.
Innovation Solution
The implementation of a powertrain design that includes a set of pre-centering and centering pins with an intermediate section of reduced diameter, allowing for radial clearance and enabling precise alignment without additional constraints, facilitating the penetration of centering pins into their respective holes and compensating for alignment faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional pre-centering pins are used without intermediate section, then the structure is simpler, but dimensional dispersions cause misalignment and hyperstatic conditions
Solution Approach 1:
The pre-centering pin is divided into three distinct sections: a rear mounting section, an intermediate section with reduced diameter, and a front pre-centering section. This segmentation allows each section to fulfill a specific function - the intermediate section provides radial clearance to accommodate dimensional dispersions while the other sections maintain structural integrity and centering capability.
Solution Approach 2:
The intermediate section acts as a mediator between the mounting section and the pre-centering section. It absorbs the dimensional variations and misalignments through its radial clearance, preventing these variations from propagating to the critical centering function, thus eliminating hyperstatic conditions.
2Productivity
If centering pins are forced into misaligned holes, then assembly can be completed, but components are stressed and integrity is compromised
Solution Approach 1:
The intermediate section with reduced diameter creates radial clearance that acts as a cushion before the centering operation. This pre-established clearance allows the centering pins to accommodate misalignments without forcing components together, preventing stress and potential damage during assembly.
3Manufacturing precision
If pre-centering pins are used to compensate for dimensional dispersions, then alignment improves, but hyperstatic conditions persist due to misalignment
Solution Approach 1:
The diameter parameter of the pre-centering pin is changed in the intermediate section to be smaller than the pre-centering hole diameter. This parameter change creates radial clearance that transforms the assembly from a hyperstatic state (where pins are forced against holes) to a state with degrees of freedom, allowing natural alignment without stress.
Data Source
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AI summary
A system to aid in the assembly of a first crankcase element (32) onto an adjacent second crankcase element (36) belonging to a powertrain (10), a system comprising at least one pre-centering pin (40) which includes: - a rear mounting section (39) and a front pre-centering section (43) in an axial pre-centering hole (44) of the second crankcase element (36), characterized in that each centering pin (40) includes an intermediate section (42) whose outside diameter is smaller than the outside diameter of the front pre-centering section (43) and which, at the end of the axial pre-centering stroke, extends axially through the axial pre-centering hole (44)