Manufacturing method of high-strength and high-pressure-resistant spark plug

Abstract

The invention discloses a manufacturing method of a high-strength high-pressure-resistant spark plug, and particularly relates to the field of spark plug manufacturing, and the manufacturing method comprises the following steps: S1, material selection: respectively selecting iridium platinum and platinum as materials of a central electrode and a side electrode, selecting steel as a metal shell, and selecting aluminum oxide ceramic as an insulator; s2, manufacturing: (1) manufacturing a central electrode; (2) manufacturing a side electrode; (3) manufacturing a metal shell; (4) manufacturing an aluminum oxide ceramic insulator; s3, assembling is carried out; assembling the central electrode, the side electrode, the metal shell and the ceramic insulator to obtain a spark plug; and S4, detection: performing appearance inspection, size detection, electrical performance test and service life test on the spark plug. The metal ring manufactured by the chromium-nickel-molybdenum alloy powder through a spray welding process has the characteristics of high temperature resistance and corrosion resistance, and the internal organization structure of the metal ring can be changed into a continuous and compact metallurgical structure by remelting after spraying, so that the service life of the metal ring is prolonged, and the service life of the spark plug is further prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of spark plug manufacturing, in particular to a method for manufacturing a high-strength and high-voltage resistant spark plug. Background Art

[0002] The spark plug is a key component in the engine, used to ignite the mixture and keep the engine running normally. The spark plug acts as an electric spark generator, which generates sparks between the center electrode and the side electrode through high voltage current. This spark then ignites the gasoline mixture, driving the piston in the cylinder to do work, thereby driving the car to run. In the normal operation of the car, the spark plug needs to operate and work continuously, so it is a vulnerable structure that needs to be replaced regularly, and the working condition of the spark plug directly affects the performance and fuel efficiency of the engine.

[0003] There are generally traditional single-side pole spark plugs and multi-side pole spark plugs on the market. The side electrode on the single-side pole spark plug covers the center electrode, which can easily lead to reduced spark performance. The multi-side pole spark has greater energy and is easier to penetrate into the cylinder, which helps to improve the combustion of the mixture and reduce exhaust emissions. There is a floating electrode on the multi-side pole spark plug, and carbon deposits are easily generated between the floating electrode composed of a metal ring and the center electrode, which not only easily affects the service life of the spark plug, but also the metal ring made by the electroplating process has a loose structure and poor mechanical properties, and is prone to cracks, affecting the strength and high-voltage resistance of the spark plug, and thus affecting the service life of the spark plug.

[0004] Therefore, we have made improvements to this and proposed a method for manufacturing a high-strength and high-voltage resistant spark plug. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] The present invention provides a method for manufacturing a high-strength and high-voltage resistant spark plug, comprising the following steps:

[0007] S1. Material selection: Iridium platinum and platinum are selected as the materials of the center electrode and side electrode respectively, steel is selected as the metal shell, and alumina ceramics is selected as the insulator;

[0008] S2. Manufacturing:

[0009] (1) Manufacturing of a center electrode: grinding a platinum-iridium alloy into powder, mixing the ground platinum-iridium alloy powder with carbon powder in a certain ratio to obtain a mixture, sintering the mixture into a block at a high temperature to obtain a block, cutting the block into a platinum-iridium electrode of a desired size, preparing fluoride and chloride on the surface of the platinum-iridium electrode by electrolysis, and soaking the electrolytically treated platinum-iridium center electrode in nitric acid for a period of time and then taking it out to obtain a center electrode;

[0010] (2) Manufacturing of side electrodes: Grind platinum into powder and mix it with carbon powder in a certain proportion, then sinter it to obtain a block, cut the block to obtain a side electrode, use an electrolytic method to prepare fluoride and chloride on the surface of the side electrode, and soak the electrolyzed side electrode in nitric acid for a period of time and then take it out;

[0011] (3) Manufacturing of metal shell: stamping steel into a hollow tube to obtain a semi-finished metal shell, grinding the semi-finished metal shell to obtain a metal shell, and pressing one end of the metal shell into a hexagonal nut shape to facilitate subsequent installation and fixation;

[0012] (4) Alumina ceramic insulator manufacturing: adding alumina powder to a solvent and stirring to obtain a slurry, pouring the slurry into a mold, vibrating and pressing to form a ceramic body, sintering the formed ceramic body to obtain an alumina ceramic insulator, forming an annular groove on the upper part of the alumina ceramic insulator, and spraying a metal material in the annular groove by a spray welding process to form a metal ring, wherein the metal material is a self-fluxing powder;

[0013] S3, assembly: welding the side electrodes to the metal shell, and adjusting the gap, inserting the center wiring screw into the ceramic insulator, and combining the two by pressing; inserting the center electrode into the center hole of the ceramic insulator and fixing it, and fixing the ceramic insulator in the metal shell to obtain the spark plug;

[0014] S4. Inspection: The assembled spark plugs are subjected to appearance inspection, size inspection, electrical performance test and life test.

[0015] As a preferred technical solution of the present invention, when manufacturing the center electrode, the platinum-iridium material ratio is 90:10, and the carbon powder content in the mixture is less than or equal to 0.03% to ensure the high temperature stability and chemical reaction activity of the material.

[0016] As a preferred technical solution of the present invention, preparing fluoride and chloride on the surface of the platinum-iridium electrode by electrolysis can ensure the quality and performance of the platinum-iridium electrode, enhance the corrosion resistance and stability of the electrode, and extend the service life of the electrode; by soaking the electrolytic platinum-iridium center electrode in nitric acid, impurities on the surface of the platinum-iridium center electrode can be removed.

[0017] As a preferred technical solution of the present invention, the central connecting screw is produced and cut by a specific lathe, and the central connecting screw can be used as a conductor for transmitting high voltage electricity to the central electrode.

[0018] As a preferred technical solution of the present invention, the self-fluxing powder is a chromium-nickel-molybdenum alloy powder with good high temperature resistance and corrosion resistance, and the mass fraction ratio of each material in the alloy powder is carbon content (C) ≤ 0.08%; chromium (Cr) content 16.5% to 19.0%; nickel (Ni) content 14.5% to 18.0%; molybdenum (Mo) content 4.5% to 5.8%.

[0019] As a preferred technical solution of the present invention, before spraying the ceramic insulator, the annular groove needs to be preheated to 320°C to 380°C, the self-fluxing powder is in a molten or semi-molten state, and the coating needs to be heated to 900°C to 1100°C after spraying.

[0020] As a preferred technical solution of the present invention, the ceramic insulator is sprayed to obtain a coating, and the coating is subjected to grinding and polishing processes to form a metal ring.

[0021] As a preferred technical solution of the present invention, the spark plug electrical performance test includes measuring the spark plug resistance value using a digital multimeter; simulating the ignition condition under the vehicle running state by a high-voltage ignition tester to observe the spark intensity and stability of the spark plug.

[0022] The beneficial effects of the present invention are:

[0023] In the present invention, the metal ring made of chromium-nickel-molybdenum alloy powder by a spray welding process has the characteristics of high temperature resistance and corrosion resistance, and the internal organizational structure of the metal ring can be transformed into a continuous and dense metallurgical structure by remelting after spraying, thereby improving its service life and further improving the service life of the spark plug.

[0024] In the present invention, iridium-platinum and platinum are selected as the materials of the central electrode and the side electrode respectively, so that the central electrode and the side electrode have the characteristics of high strength, high corrosion resistance and high melting point, which can meet the needs of high-power engines and are resistant to high temperatures, making the electrodes not easy to melt and be damaged. The central electrode and the side electrode are electrolytically treated by an electrolytic method, which can ensure the quality and performance of the platinum-iridium electrode, enhance the corrosion resistance and stability of the electrode, and extend the service life of the electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 It is a manufacturing step flow chart of a manufacturing method of a high-strength and high-voltage resistant spark plug of the present invention;

[0027] Figure 2 The present invention discloses a spark plug assembly flow chart in a method for manufacturing a high-strength and high-voltage resistant spark plug. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0029] Example: Figure 1 and Figure 2 As shown, a method for manufacturing a high-strength and high-voltage resistant spark plug of the present invention comprises the following steps:

[0030] S1. Material selection: Iridium platinum and platinum are selected as the materials of the center electrode and side electrode respectively. They have the advantages of high strength, high corrosion resistance, high melting point, etc., which can meet the needs of high-power engines and withstand high temperatures, making the electrodes not easy to melt and damage. Steel is selected as the metal shell, and the steel is 20# high-quality steel; alumina ceramics are selected as insulators;

[0031] S2. Manufacturing:

[0032] (1) Manufacturing of the center electrode: Grind the platinum-iridium alloy into powder, during which the grinding time and method are precisely controlled to ensure the particle size and uniformity of the powder; mix the ground platinum-iridium alloy powder with carbon powder in a certain proportion to obtain a mixture; sinter the mixture into a block at a high temperature to obtain a block; this process requires precise control of the sintering time and temperature to ensure that the structure and performance of the platinum-iridium electrode meet the design requirements; cut the block into platinum-iridium electrodes of a desired size; prepare fluoride and chloride on the surface of the platinum-iridium electrode by electrolysis; this process requires strict control of the electrolysis time and voltage to ensure that the fluoride and chloride on the electrode surface are uniform and stable; soak the electrolytically treated platinum-iridium center electrode in nitric acid for a period of time and then take it out to obtain the center electrode;

[0033] (2) Manufacturing of side electrodes: Grind platinum into powder and mix it with carbon powder in a certain proportion, then sinter it to obtain a block, cut the block to obtain a side electrode, use an electrolytic method to prepare fluoride and chloride on the surface of the side electrode, and soak the electrolyzed side electrode in nitric acid for a period of time before taking it out. The precautions in the manufacturing process are the same as those in the production process of the center electrode. The processing time and temperature of each stage can be determined according to the time and temperature required in the actual production process;

[0034] (3) Manufacturing of metal shell: stamping steel into a hollow tube to obtain a semi-finished metal shell, grinding the semi-finished metal shell to obtain a metal shell, and pressing one end of the metal shell into a hexagonal nut shape to facilitate subsequent installation and fixation;

[0035] (4) Alumina ceramic insulator manufacturing: Alumina powder is added to a solvent and stirred to obtain a slurry, the slurry is poured into a mold, and after vibration and pressing, a ceramic body is formed, and the formed ceramic body is sintered to obtain an alumina ceramic insulator, an annular groove is formed on the upper part of the alumina ceramic insulator, and a metal material is sprayed into the annular groove by a spray welding process to form a metal ring, and the metal material is a self-fluxing powder;

[0036] S3, assembly: welding the side electrodes to the metal shell, and adjusting the gap, inserting the center wiring screw into the ceramic insulator, and combining the two by pressing; inserting the center electrode into the center hole of the ceramic insulator and fixing it, and fixing the ceramic insulator in the metal shell to obtain the spark plug;

[0037] S4. Inspection: The assembled spark plugs are inspected for appearance, size, electrical performance and life. The electrical performance test of the spark plugs includes measuring the resistance of the spark plugs with a digital multimeter; simulating the ignition condition of the vehicle under running conditions with a high-voltage ignition tester, and observing the spark strength and stability of the spark plugs.

[0038] The inspection also includes the distance detection between the center electrode and the side electrode of the spark plug. The electrode gap should be between 0.6-1.0mm. It is detected using a spark plug gap measurer. Too large or too small will affect the ignition effect of the spark plug; the spark plug insulator is tested by testing the insulation performance with a multimeter. The insulation resistance should be between 5-20 megohms; use a thickness gauge or a special gap measuring tool to detect the gap between the spark plug electrodes to ensure that it meets the standard value; use X-rays to detect the internal structure of the spark plug, especially to check whether there are hidden cracks or internal damage.

[0039] When the center electrode is manufactured, the platinum-iridium material ratio is 90:10, and the carbon powder content in the mixture is less than or equal to 0.03% to ensure the high temperature stability and chemical reactivity of the material.

[0040] The preparation of fluoride and chloride on the surface of the platinum-iridium electrode by electrolysis can ensure the quality and performance of the platinum-iridium electrode, enhance the corrosion resistance and stability of the electrode, and extend the service life of the electrode; by removing chloride and immersing the electrolytic platinum-iridium center electrode in nitric acid, impurities on the surface of the platinum-iridium center electrode can be removed.

[0041] The center terminal screw is produced and cut by a special lathe, and the center terminal screw can serve as a conductor for transmitting high voltage electricity to the center electrode.

[0042] The self-fluxing powder is a chromium-nickel-molybdenum alloy powder with good high temperature resistance and corrosion resistance, and the mass fraction ratio of each material in the alloy powder is carbon content (C) ≤ 0.08%; chromium (Cr) content 16.5% to 19.0%; nickel (Ni) content 14.5% to 18.0%; molybdenum (Mo) content 4.5% to 5.8%.

[0043] Before spraying the ceramic insulator, the annular groove needs to be preheated to 320℃~380℃, the self-fluxing powder is in a molten or semi-molten state, and the coating needs to be heated to 900℃~1100℃ after spraying. Before spraying the ceramic insulator, place it on the spraying equipment and rotate it slowly around the center axis.

[0044] The ceramic insulator is sprayed to obtain a coating, which is then ground and polished to form a metal ring. During spraying, multiple intermittent spraying is required, and the time difference between the spraying and the coating is between 30 minutes and 45 minutes. Before continuing to spray, the temperature of the metal ring needs to be between 450 and 600 degrees Celsius. After multiple sprayings have satisfied the requirements, the metal ring needs to be remelted at a temperature of 9000 to 11500 degrees Celsius. Remelting can transform the internal structure of the metal ring into a metallurgical bonding structure, thereby improving its performance and service life.

[0045] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for manufacturing a high-strength and high-voltage resistant spark plug, characterized in that: The following steps are involved: S1. Material selection: Iridium platinum and platinum are selected as the materials of the center electrode and side electrode respectively, steel is selected as the metal shell, and alumina ceramics is selected as the insulator; S2. Manufacturing: Manufacturing of the center electrode: grinding a platinum-iridium alloy into powder, mixing the ground platinum-iridium alloy powder with carbon powder in a certain proportion to obtain a mixture, sintering the mixture into a block at a high temperature to obtain a block, cutting the block into a platinum-iridium electrode of a desired size, preparing fluoride and chloride on the surface of the platinum-iridium electrode by electrolysis, soaking the electrolytically treated platinum-iridium center electrode in nitric acid for a period of time and then taking it out to obtain the center electrode; Manufacturing of the side electrode: Grind platinum into powder and mix it with carbon powder in a certain proportion, then sinter it to obtain a block, cut the block to obtain the side electrode, use an electrolytic method to prepare fluoride and chloride on the surface of the side electrode, and soak the electrolyzed side electrode in nitric acid for a period of time and then take it out; Manufacturing of metal shell: stamping steel into a hollow tube to obtain a semi-finished metal shell, grinding the semi-finished metal shell to obtain a metal shell, and pressing one end of the metal shell into a hexagonal nut shape to facilitate subsequent installation and fixation; Alumina ceramic insulator manufacturing: Alumina powder is added to a solvent and stirred to obtain a slurry, the slurry is poured into a mold, and after vibration and pressing, a ceramic body is formed, and the formed ceramic body is sintered to obtain an alumina ceramic insulator, an annular groove is formed on the upper part of the alumina ceramic insulator, and a metal material is sprayed in the annular groove by a spray welding process to form a metal ring, and the metal material is a self-fluxing powder; S3, assembly: welding the side electrodes to the metal shell, and adjusting the gap, inserting the center wiring screw into the ceramic insulator, and combining the two by pressing; inserting the center electrode into the center hole of the ceramic insulator and fixing it, and fixing the ceramic insulator in the metal shell to obtain the spark plug; S4. Inspection: The assembled spark plugs are subjected to appearance inspection, size inspection, electrical performance test and life test.

2. The method for manufacturing a high-strength and high-voltage resistant spark plug according to claim 1, characterized in that: When the center electrode is manufactured, the ratio of platinum to iridium is 90:10, and the carbon powder content in the mixture is less than or equal to 0.03% to ensure the high temperature stability and chemical reaction activity of the material.

3. The method for manufacturing a high-strength and high-voltage resistant spark plug according to claim 1, characterized in that: The preparation of fluoride and chloride on the surface of the platinum-iridium electrode by electrolysis can ensure the quality and performance of the platinum-iridium electrode, enhance the corrosion resistance and stability of the electrode, and extend the service life of the electrode; by removing chloride and immersing the electrolytic platinum-iridium center electrode in nitric acid, impurities on the surface of the platinum-iridium center electrode can be removed.

4. The method for manufacturing a high-strength and high-voltage resistant spark plug according to claim 1, characterized in that: The central connecting screw is produced and cut by a special lathe, and the central connecting screw can be used as a conductor for transmitting high voltage electricity to the central electrode.

5. The method for manufacturing a high-strength and high-voltage resistant spark plug according to claim 1, characterized in that: The self-fluxing powder is a chromium-nickel-molybdenum alloy powder with good high temperature resistance and corrosion resistance, and the mass fraction ratio of each material in the alloy powder is carbon content (C) ≤ 0.08%; chromium (Cr) content 16.5% to 19.0%; nickel (Ni) content 14.5% to 18.0%; molybdenum (Mo) content 4.5% to 5.8%.

6. The method for manufacturing a high-strength and high-voltage resistant spark plug according to claim 5, characterized in that: Before spraying the ceramic insulator, the annular groove needs to be preheated to 320°C to 380°C, the self-fluxing powder is in a molten or semi-molten state, and the coating needs to be heated to 900°C to 1100°C after spraying.

7. The method for manufacturing a high-strength and high-voltage resistant spark plug according to claim 6, characterized in that: The ceramic insulator is sprayed to obtain a coating, and the coating is subjected to grinding and polishing processes to form a metal ring.

8. The method for manufacturing a high-strength and high-voltage resistant spark plug according to claim 1, characterized in that: The spark plug electrical performance test includes measuring the spark plug resistance value using a digital multimeter; simulating the ignition condition under the vehicle running state by a high-voltage ignition tester, and observing the spark strength and stability of the spark plug.

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