Compressor Motor Back Yoke Gap Insulation
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Solution Overview
Problem
Welding a motor to a compressor casing can cause melting of insulating members due to heat transfer, particularly in motors with concentrated windings, where the back yoke portion is thinner, leading to potential electrical insulation failure.
Innovation Solution
A compressor design with a gap between the back yoke portion and the insulating member, using aramid-based resin for the insulating material with higher Young's modulus than PET, and optionally laminating multiple insulating members, along with recesses in the back yoke portion to absorb thermal stress and improve magnetic flux balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the back yoke portion is made thinner to reduce motor size, then the motor dimensions are reduced, but the welding heat is more easily transferred to the insulating member causing melting
Solution Approach 1:
The patent introduces an intermediary substance (insulating member) with high heat resistance and low thermal conductivity between the back yoke portion and the coil to block heat transfer from welding operations, preventing insulation damage while maintaining thin back yoke design
Solution Approach 2:
The patent applies protective measures beforehand by selecting insulating materials with high heat resistance and low thermal conductivity, and by optimizing the arrangement of insulating members and cooling passages to cushion against welding heat before it can reach and damage the coil insulation
2Strength
If welding is performed to join motor to casing, then the motor is securely fixed in the casing, but the welding heat causes melting of the insulating member
Solution Approach 1:
The patent uses insulating members as intermediary protective layers between the welding zone and the electrical components, allowing secure welding while preventing heat damage to insulation and maintaining electrical reliability
Solution Approach 2:
The patent applies different thermal protection strategies to different locations: high heat resistance materials are positioned at critical heat exposure zones, and cooling passages are strategically placed to provide localized thermal management where welding heat is most intense
3Ease of manufacture
If conventional insulating materials are used, then the material is easy to work with, but the material warps under thermal stress and cannot effectively block heat transfer
Solution Approach 1:
The patent employs composite insulating structures combining multiple materials with complementary properties - high heat resistance materials for thermal blocking, low thermal conductivity materials for heat isolation, and warp-resistant materials with high Young's modulus to maintain structural integrity under thermal stress
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
Prevents melting of insulating members by reducing heat transfer, enhances reliability and dielectric strength, and minimizes electromagnetic vibration and noise, while maintaining efficiency and cost-effectiveness.
Implementation Method 1
a gap being provided between the back yoke portion and the insulating member... restrains the welding heat from being transferred to the insulating member
Implementation Method 2
the at least one insulating member is made of an aramid-based resin... whose Young's modulus is greater than PET which is a typically used material for the insulating member. This way, the insulating member is hardly warped
Data Source
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AI summary
Melting of an insulating member disposed in a slot is restrained. A compressor of the present invention includes a pipe 11 and a motor disposed inside the pipe 11, which is jointed to the pipe 11 by welding at a plurality of weld positions P1 to P3. The motor includes an annular back yoke portion 75, a plurality of tooth portions 76 protruding from the back yoke portion 75 in the radial direction (X-direction), a core 71 having a slot 77 formed between the tooth portions 76 adjacent to each other, a coil 72 disposed in the slot 77, and a slot cell 73 made of an aramid-based resin, which is disposed in the slot 77 and which insulates the coil 72 from the core 71. Between the back yoke portion 75 and the slot cell 73 is provided a gap S1.