Drive Member Welding for High Torque Alternator Shafts
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Solution Overview
Problem
Existing assembly methods for drive members, such as pulleys, on rotating electrical motor shafts fail to withstand high torque levels, particularly during the starting of heat engines, leading to potential loosening of the pulley.
Innovation Solution
A supplementary welded link is established between the drive member and the shaft, utilizing welding techniques like TIG, laser, or MIG welding, to enhance the assembly's stability and torque transmission without significant modifications to the existing assembly device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a drive member is assembled by screwing onto a shaft using only threaded engagement, then the assembly device is simple with reduced number of parts, but the assembly cannot withstand high torque levels greater than 70 Nm and tends to loosen during heat engine starting
Solution Approach 1:
The invention merges two different connection methods: threaded engagement and welding. The drive member is first screwed onto the shaft using threaded sections, then a welded link is created between the drive member and shaft to form a combined mechanical-thermal connection that can withstand high torque levels while maintaining simplicity
Solution Approach 2:
The connection becomes composite by combining two different joining mechanisms: the mechanical threaded connection and the thermal weld connection. This composite approach allows the assembly to benefit from both the ease of threaded assembly and the high strength of welding
2Force
If the pulley is screwed onto the shaft with tension applied against an axial stop, then the assembly provides resistance to slippage, but the torque tends to loosen the pulley during heat engine starting
Solution Approach 1:
The welded link is created in advance to prevent the loosening effect that would occur during heat engine starting. The weld acts as a preliminary countermeasure against the reverse torque that tends to loosen the pulley, ensuring stability before the high-torque starting operation occurs
3Reliability
If a welded link is added between the drive member and shaft, then the assembly can transmit major torque levels and withstand acyclism, but the manufacturing process becomes more complex with additional welding operations
Solution Approach 1:
The threaded assembly is performed first as a preliminary step, positioning the drive member correctly on the shaft before the welding operation. This preliminary mechanical assembly ensures proper alignment and positioning, making the subsequent welding process easier and more reliable
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 solution provides a stable and reliable assembly capable of transmitting high torque levels and resisting acyclism in heat engines, ensuring a secure connection between the drive member and the shaft.
Implementation Method 1
a supplementary welded link is effected between the front face of the base or the sleeve of the drive member and the threaded part of the shaft
Data Source
AI summary
The invention relates to a device for assembling, by screwing, a drive member, such as a drive pulley, with a shaft intended to be coupled to the rotor of a rotating electrical machine, the device including an additional, welded connection. According to the invention, this method of producing the assembly device is characterized in that the drive member screwed onto its shaft in the vertical position is welded from below. The invention can be used for rotating electrical machines, such as an alternator or a starter-alternator of a motor vehicle.