Superconducting Rotating Machine Sliding Part Hard Coating
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Solution Overview
Problem
Conventional superconducting rotating machines face issues with thermal insulating properties and wear resistance due to the materials used in their sliding parts, leading to excessive heat input and thermal contraction, which affects the performance and durability of large-scale superconducting machines like superconducting motors.
Innovation Solution
The implementation of a superconducting rotating machine design featuring a sliding part with a hard coating film made of fiber-reinforced plastic (FRP) and a heat input suppressing part also made of FRP, where the hard coating film is harder than the FRP and has a smooth connection to the heat input suppressing part, reducing thermal conductivity and enhancing wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a member made of titanium or titanium alloy is used for the sliding part, then the mechanical strength is improved, but the thermal insulating property deteriorates resulting in large heat input amount
Solution Approach 1:
The patent applies composite materials by combining fiber-reinforced plastic (providing thermal insulation) with a hard coating film (providing wear resistance and sufficient mechanical strength). This composite structure resolves the contradiction by integrating materials with complementary properties: the FRP base material suppresses heat input to the superconducting coil, while the hard coating film ensures the sliding surface can withstand mechanical loads and wear.
Solution Approach 2:
The patent applies local quality by creating a layered structure where different materials serve different functions at different locations. The fiber-reinforced plastic forms the bulk structure for thermal insulation, while a hard coating film is applied only to the sliding surface where mechanical strength and wear resistance are critical. This localized material differentiation optimizes both thermal and mechanical performance.
2Ease of operation
If graphite-containing Teflon is used for the sliding part, then the lubricity is improved, but the wear resistance deteriorates
Solution Approach 1:
The patent uses composite materials where fiber-reinforced plastic provides the base structure with inherent lubricity, and a hard coating film is applied on top to provide wear resistance. This composite approach allows the sliding part to maintain low friction while achieving sufficient wear resistance that pure graphite-containing Teflon cannot provide.
Solution Approach 2:
The patent applies local quality by having the hard coating film specifically on the sliding surface where wear occurs, while the underlying fiber-reinforced plastic maintains the lubricity function. This localized differentiation allows each layer to optimize its specific function without compromising the other.
3Stability of the object's composition
If the sliding part is designed to absorb thermal contraction, then the thermal expansion compensation is improved, but the weight of the rotor core increases
Solution Approach 1:
The patent applies parameter changes by utilizing the thermal contraction characteristics of the fiber-reinforced plastic material itself to absorb thermal expansion differences. The FRP material's inherent thermal properties are leveraged to compensate for thermal effects, eliminating the need for additional heavy compensation mechanisms while maintaining rotor core stability.
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
This design significantly reduces thermal conductivity by a factor of 1/20 and improves wear resistance, allowing the superconducting coil to maintain an extremely low temperature and withstand thermal contraction and frictional forces without significant wear.
Implementation Method 1
at least one of the first sliding surface and the second sliding surface has a surface of a hard coating film located to partially cover a heat input suppressing part made of fiber-reinforced plastic... significantly reduces thermal conductivity by a factor of 1/20
Implementation Method 2
a superconducting rotating machine utilizing superconductivity... a superconducting coil held by the rotating shaft and cooled by a coolant
Implementation Method 3
The spoke is made of titanium... while the material of the supporting ring is made of graphite-containing Teflon having low thermal conductivity and excellent lubricity. Therefore, sliding surfaces of the supporting ring and the slide ring are made of graphite-containing Teflon. This superconducting rotating machine has the slide ring made slidable against the supporting ring so that an axial thermal strain can be absorbed by a slide therebetween
Data Source
Figure 1
Figure 2~3
Figure 4~6
AI summary
A sliding surface located to one side in the axial direction relative to the axially central position of a rotary shaft 1 is supported by the slide surface of a supply shaft 2 in a slidable manner in the axial direction, the slide surface being the surface on which sliding occurs. The portion located to the other side in the axial direction side relative to the axially central position of the rotary shaft 1 is fixed to an output shaft 3. The sliding surface is positioned on the surface of a hard coating 51, and the hard coating 51 is positioned so as to cover a part of a substrate 50 made of a GFRP. The slide surface is positioned on the surface of a hard coating 56, and the hard coating 56 is positioned so as to cover a part of a substrate 55 made of a GFRP. A superconducting rotating machine is thereby provided in which heat insulation properties and the wear resistance of the sliding part can be improved despite the presence of a sliding part and the ability to absorb thermal contraction.