Electric Machine Drive Train Assembly for Stiff Single-Piece Housings
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Solution Overview
Problem
Conventional drive train assemblies for wind turbines face challenges in achieving improved stiffness while maintaining cost-effectiveness, as single-piece housings require expensive tapered roller bearings for assembly.
Innovation Solution
A method and design for assembling a drive train using a single-piece housing with spherical roller bearings, employing a sequence of temporary heating and positioning steps for bearings and covers to enhance stiffness and reduce weight, while maintaining the use of conventional spherical roller bearings and assembly tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single-piece housing is used to improve stiffness and reduce weight, then the stiffness and weight are improved, but expensive tapered roller bearings must be used for assembly
Solution Approach 1:
The patent changes the physical state of the bearing components by temporarily heating them to expand, enabling assembly into the single-piece housing. After assembly, the components cool and contract to achieve tight interference fits without requiring expensive tapered roller bearings. This parameter change (temperature) allows conventional spherical roller bearings to be used instead of expensive alternatives.
Solution Approach 2:
The patent utilizes thermal expansion and contraction phase transitions to enable the assembly process. The bearing components are heated to expand their outer dimensions, allowing them to be inserted into the housing. Upon cooling, they contract to create secure interference fits, eliminating the need for expensive specialized bearings while maintaining assembly feasibility with a single-piece housing.
2Weight of stationary object
If a single-piece housing is used to reduce the number of parts, then the weight is reduced, but the assembly complexity increases due to bearing installation requirements
Solution Approach 1:
The patent applies preliminary heating to the bearing components before assembly to expand them, making installation into the single-piece housing feasible. This preliminary thermal action simplifies the assembly process by enabling components to be installed in a predetermined sequence without requiring complex specialized bearing housings, thus reducing overall weight while managing assembly complexity.
Solution Approach 2:
By changing the temperature parameter of the bearing components during assembly, the patent enables straightforward installation into the single-piece housing. The thermal expansion allows components to be inserted easily, and subsequent cooling creates secure fits, reducing assembly complexity compared to what would be required without thermal assistance.
3Ease of manufacture
If conventional spherical roller bearings are used with a single-piece housing, then cost is reduced, but assembly difficulty increases without proper heating and positioning methods
Solution Approach 1:
The patent changes the temperature parameter of the bearing components during assembly, heating them to expand for easier installation into the single-piece housing. This parameter change makes assembly of conventional spherical roller bearings feasible without increasing cost, while the controlled heating and cooling process actually simplifies the assembly operation compared to cold assembly methods.
Solution Approach 2:
The patent introduces thermal energy as an intermediary to facilitate the assembly of conventional spherical roller bearings into the single-piece housing. The temporary heating acts as a mediator that enables easy installation, and the subsequent cooling creates secure fits, making the assembly process easier while maintaining cost-effectiveness with conventional bearings.
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 method increases the stiffness of the drive train assembly, reduces the weight of the main frame, and decreases the number of bolts in the housing/main frame interface, while maintaining cost-effectiveness and allowing for maintainability throughout the drive train's lifespan.
Implementation Method 1
mounting the housing to the shaft by temporarily heating the housing and relatively moving the same over the shaft
Implementation Method 2
mounting the front bearing to the shaft by temporarily heating the front bearing and shifting the same to a front position at the shaft; mounting the rear bearing to the shaft by temporarily heating the rear bearing and shifting the same from the rear end of the shaft to a rear position at the shaft
Data Source
AI summary
A drive train for an electric machine is provided. The drive train includes a shaft. The shaft has a front end and a rear end and which is supported in a housing via a front bearing and a rear bearing, wherein the front bearing including a front bearing outer ring and a front bearing inner ring, and the rear bearing including a rear bearing outer ring and a rear bearing inner ring). The drive train includes a first cover mounted to the housing and being configured to seal a rear side of the front bearing, wherein the first cover is mounted to the housing by an auxiliary support which connects the first cover to the housing, a second cover mounted to the housing and being configured to seal a front side of the rear bearing, a third cover mounted to the housing and being configured to seal the rear bearing.