Ceramic Heater Joining via Metallized Layer Mass Transfer
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Solution Overview
Problem
The existing manufacturing methods for ceramic heater-type glow plugs are costly due to complex structures and insufficient joining strength between the ceramic heater and the outer cylinder, primarily because the brazing material is located near the heat-generating section, leading to oxidation and reduced joining efficiency.
Innovation Solution
A method involving the formation of a metallized layer on the ceramic heater, press-insertion into a metallic outer cylinder, and heating to achieve mass transfer between the outer cylinder and the metallized layer for joining, with silver plating and oxidation-resistant layers to enhance strength and simplify the process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If brazing material is placed on the step portion of the outer cylinder to join the ceramic heater, then the ceramic heater can be held by the outer cylinder, but the manufacturing process becomes complex and costly due to the need for step formation and plating
Solution Approach 1:
The invention extracts the harmful step structure from the outer cylinder design. Instead of forming a step in the outer cylinder to hold the brazing material, the brazing material is applied directly to the end surface of the ceramic heater itself. This eliminates the complex step formation and plating processes on the outer cylinder while maintaining effective joining.
Solution Approach 2:
The ceramic heater's end surface acts as an intermediary carrier for the brazing material. By applying the brazing material directly to the ceramic heater's end surface, the invention uses the ceramic heater itself as the platform for joining, eliminating the need for specialized outer cylinder structures like steps and plating layers.
2Ease of manufacture
If the length of the ceramic heater is reduced to cut manufacturing cost, then manufacturing cost decreases, but the outer cylinder structure becomes more complicated to ensure proper joining
Solution Approach 1:
The invention removes the complex outer cylinder step structure and plating requirements, allowing the ceramic heater length to be reduced without complicating the outer cylinder design. The simplified joining method using direct brazing material application to the ceramic heater end enables cost-effective manufacturing with shorter ceramic heaters.
3Strength
If brazing material is located near the heat generating section of the ceramic heater, then joining can be achieved, but the copper component in the brazing material is oxidized by heat, reducing joining strength
Solution Approach 1:
The invention applies protective measures preliminarily by positioning the brazing material on the ceramic heater end surface away from the heat generating section. This preliminary positioning prevents the brazing material from being exposed to high temperatures during operation, thereby preventing oxidation of the copper component before it occurs.
Solution Approach 2:
The invention converts the potential harm of high temperature exposure into a benefit by deliberately positioning the brazing material away from the heat generating section. The heat zone that could cause oxidation is used to define the optimal placement zone for the brazing material, ensuring it remains in a cooler, oxidation-free environment.
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 approach simplifies the structure, reduces manufacturing costs, and ensures sufficient joining strength between the ceramic heater and the outer cylinder, preventing oxidation and improving durability.
Implementation Method 1
heating the ceramic heater and the outer cylinder at a temperature at which a material for forming the metallized layer becomes a semi-molten state and performing joining by mass transfer between the outer cylinder and a solid layer of the metallized layer
Implementation Method 2
these are heated to a temperature at which the brazing material is melted, and the molten brazing material flows between a surface of the ceramic heater and the inner surface of the outer cylinder
Data Source
Figure 1
Figure 2
Figure 3(a)~3(e)
AI summary
To simplify a structure and a manufacturing process of a ceramic heater-type glow plug so as to cut manufacturing cost. A manufacturing method of a ceramic heater-type glow plug (1) including: a ceramic heater (11); and a metallic outer cylinder (12), one end of which holds the ceramic heater and the other end of which is fixed to a housing (14) has: a step of forming a metallized layer (116) on at least a portion of a surface region in the ceramic heater that is held by the outer cylinder (12); a step of press-inserting at least the metallized layer of the ceramic heater in the outer cylinder; and a step of heating the ceramic heater and the outer cylinder at a temperature at which a material for forming the metallized layer becomes a semi-molten state and performing joining by mass transfer between the outer cylinder and a solid layer of the metallized layer.