Compression-Bonded Magnet With Hermetic Case Sealing
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Solution Overview
Problem
Conventional compression-bonded magnets face challenges in achieving high magnetic properties and corrosion resistance while maintaining durability and moldability, especially in corrosive environments, with existing methods being costly and inefficient.
Innovation Solution
A compression-bonded magnet with a case, comprising a rare earth magnet powder and a thermosetting resin binder, is hermetically sealed within a non-magnetic case using a thermosetting resin sealing member, allowing for increased magnet powder volume ratio and reduced resin binder, enhancing magnetic properties and corrosion resistance without high-temperature heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the magnet powder amount is increased to improve magnetic properties, then the magnetic properties are improved, but the durability strength and adhesion strength may deteriorate
Solution Approach 1:
The patent applies parameter changes by optimizing the magnet powder volume ratio to 90% or more, which is higher than conventional compression-bonded magnets. This parameter change enables achieving high magnetic properties while maintaining sufficient structural integrity through the hermetic sealing design that protects the magnet from corrosion.
Solution Approach 2:
The patent uses a cost-effective approach by employing a hermetic sealing structure with a case and sealing member that protects the magnet powder from corrosion without requiring expensive alternative materials. The sealing structure acts as a protective barrier that extends the magnet's service life in corrosive environments.
2Ease of manufacture
If conventional compression-bonded magnets are used, then they are easy to process and have good dimensional accuracy, but they have poorer magnetic properties compared to binderless sintered magnets
Solution Approach 1:
The patent changes the magnet powder volume ratio parameter to 90% or more, which is significantly higher than conventional compression-bonded magnets. This parameter change brings the magnetic properties closer to binderless sintered magnets while retaining the compression-molding processing advantages and dimensional accuracy.
3Reliability
If rare earth magnet powders are used to improve magnetic properties, then the magnetic properties are improved, but the magnets are susceptible to oxidation corrosion and internal rust penetration
Solution Approach 1:
The patent extracts the magnet powder from direct exposure to corrosive environments by enclosing it within a hermetic sealing structure consisting of a case and sealing member. This separation protects the rare earth magnet powder from oxidation and rust penetration while preserving its high magnetic properties.
Solution Approach 2:
The hermetic sealing structure acts as an intermediary barrier between the rare earth magnet powder and the corrosive environment. The sealing member with protrusions fitting into grooves of the case creates a hermetic seal that prevents corrosive substances from reaching the magnet powder.
4Object-affected harmful factors
If a resin coating is formed on the magnet surface to prevent corrosion, then corrosion resistance is improved, but the production process becomes more complex and costly
Solution Approach 1:
The patent extracts the corrosion protection function from surface coatings and implements it through a hermetic sealing structure. Instead of applying multiple resin coatings to the magnet surface, the magnet is enclosed within a sealed case, simplifying the production process while providing superior corrosion protection.
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 cost-effective, high-productivity compression-bonded magnet with improved magnetic properties and corrosion resistance, suitable for corrosive environments, by increasing the magnet powder volume ratio and integrating the sealing member with the case, thus preventing rust and maintaining structural integrity.
Implementation Method 1
a compression-bonded magnet including a rare earth magnet powder and a resin binder of a thermosetting resin
Implementation Method 2
the compression-bonded magnet is hermetically sealed by the sealing member and the case
Data Source
AI summary
There is provided a compression-bonded magnet with a case, which can realize high magnetic properties, high corrosion resistance and high durability strength even at low cost. The compression-bonded magnet with a case is a compression-bonded magnet with a case 1, comprising: a compression-bonded magnet 2 comprising a rare earth magnet powder such as an isotropic Nd—Fe—B magnet powder and a resin binder of a thermosetting resin; a case 3 for inserting the compression-bonded magnet 2; and a sealing member 4, wherein the compression-bonded magnet 2 is formed by compression-molding a mixture comprising the rare earth magnet powder and the resin binder into a green compact and curing the resin binder contained in the green compact, the rare earth magnet powder is contained in a large amount with respect to the entire compression-bonded magnet (for example, in a volume ratio of 85% to 90%), the sealing member 4 is fixed at an insertion opening part 3a of the case 3, and the compression-bonded magnet 2 is hermetically sealed by the sealing member 4 and the case 3.