A discharge voltage test fixture under gas pressure to prevent insulator fragmentation

Abstract

The present application belongs to the technical field of ignition nozzle testing, and specifically relates to a discharge voltage test fixture under air pressure that prevents insulators from breaking. The test fixture comprises a lower shell (17), the top end of which is provided with an internal thread on the inner wall surface; an upper shell (11) is assembled on the top end of the lower shell (17) through a threaded connection; an insulating bushing (16) is arranged in the lower shell (17) and has a top contact surface; a rubber ring (9) is arranged between the top extrusion surface of the lower shell (17) and the top wall of the discharge voltage test bench; the outer side of the head of the insulator (8) is a conical surface, and a side electrode (13) is sleeved, and a center electrode (12) is installed in the center of the insulator, the top contact surface of the insulating bushing (16) is pressed from bottom to top on the step of the insulator, and the bottom end surface of the upper shell (11) is pressed from top to bottom on the side electrode of the head of the insulator, thereby fixing the insulator in the lower shell. The present application reduces the risk of insulator breaking during assembly.

Description

Technical Field

[0001] The present application belongs to the technical field of ignition nozzle testing, and in particular relates to a discharge voltage testing fixture under air pressure for preventing an insulator from breaking. Background Art

[0002] The semiconductor nozzle is an important ignition product in the aircraft engine ignition system. Its main function is to convert the high-voltage electric energy provided by the ignition device into an electric spark with a certain energy through breakdown discharge at the discharge gap of the semiconductor nozzle, and ignite the air-fuel mixture in the engine combustion chamber. In order to ensure the working reliability of the semiconductor nozzle, the top of the insulator in the semiconductor nozzle usually has a semiconductor glaze. Therefore, it is necessary to test the minimum discharge voltage of the insulator under air pressure to screen out the insulator that meets the requirements.

[0003] During the test, the insulator is tightly assembled in a special test fixture, such as Figure 1 As shown, the original lower shell 7 and the original support plate 4 are argon arc welded into one; the original connecting rod 5 is inserted into an original insulating bushing 6, and then installed into the original lower shell 7 together; a proper amount of sealant is filled into the original lower shell 7, and then another original insulating bushing 6 is pressed into the original lower shell 7; the sealant part is induction heated and the two original insulating bushings 6 are pressed to ensure that the special test fixture does not leak; the original center electrode 2 is passed through the insulator 8 (test piece) and tightened to the original connecting rod 5; the original side electrode 3 is put on the insulator 8; the original upper shell 1 is tightened to the original lower shell 7, and finally the rubber ring 9 is placed on the original upper shell 1, and then it is installed on the minimum discharge voltage test bench, the power is turned on, the air pressure is adjusted to the specified value, and then the voltage is gradually loaded from low to high between the two electrodes, and a discharge test is performed until an electric spark is generated. At this time, the loaded voltage is the minimum discharge voltage under air pressure.

[0004] The existing problem is that the insulator 8 taken out from the special test fixture after the test is broken, causing the insulator 8 to be scrapped. At the same time, the test fixture causes quality problems for the insulator 8 that has not been broken, reducing the reliability of the semiconductor nozzle. The reason for the breakage of the insulator 8 is that the insulator 8 is tightly assembled in the special test fixture during the test, otherwise the test result will be inaccurate. Figure 1It can be seen that the insulator 8 fits with the original connecting rod 5 at point A. The fitting part of the insulator 8 is the place where the wall thickness of the insulator 8 is the smallest and the weakest. In addition, the end surface of some insulators 8 is uneven, which causes the local stress to increase. At the same time, when the test fixture is installed on the minimum discharge voltage test bench, the rubber ring 9 and the original upper shell 1 are tightly matched to ensure the airtightness of the discharge part under the air pressure of 1MPa. Therefore, when the airtight device of the minimum discharge voltage test bench is tightened, the original upper shell 1 of the special test fixture will be further tightened along with the rubber ring 9, so that the insulator 8 is subjected to a second force, causing the insulator 8 to break. The insulator 8 that has not broken will also be damaged, and it will cause hidden dangers to the quality of the semiconductor nozzle. Summary of the invention

[0005] In order to solve the above problems, the present application provides a discharge voltage test fixture under air pressure that prevents the insulator from breaking, thereby reducing the risk of breaking when the insulator is assembled.

[0006] The discharge voltage test fixture under air pressure for preventing the insulator from breaking provided in the present application mainly includes:

[0007] The lower shell is a hollow cylinder structure, fixed in the discharge voltage test bench, the top of the cylinder is provided with an internal thread on the inner wall surface, and the top of the cylinder has an annular extrusion surface D;

[0008] The upper shell has external threads and is assembled on the top of the cylinder of the lower shell through threaded connection;

[0009] An insulating bushing is arranged in the lower shell, and the top of the insulating bushing has a top connection surface C, and the center of the insulating bushing has a containing space;

[0010] The rubber ring is arranged between the top extrusion surface D of the lower shell and the top wall of the discharge voltage test bench;

[0011] The outer side of the insulator head is a conical surface and is sleeved with a side electrode. A central electrode is installed in the center of the insulator. The central electrode is connected to a connecting rod at the tail end of the insulator. The connecting rod extends to the outside of the discharge voltage test bench through the accommodating space of the insulating bushing. The top connection surface C of the insulating bushing is pressed from bottom to top on the step of the insulator, and the bottom end surface of the upper shell is pressed from top to bottom on the side electrode of the insulator head, thereby fixing the insulator in the lower shell.

[0012] Preferably, a portion of the upper shell exposed outside the lower shell is clearance-fitted with the rubber ring.

[0013] Preferably, the insulating bushing is made of bakelite.

[0014] Preferably, the bottom end of the cylinder of the lower shell has an inwardly contracted annular step, and the insulating bushing includes a first cylinder with a larger outer diameter and a second cylinder with a smaller outer diameter, an extrusion step is formed between the first cylinder and the second cylinder, the first cylinder is located in the lower shell, the extrusion step is extruded on the inner wall surface B of the annular step of the lower shell, and the second cylinder passes through the annular step of the lower shell and extends out of the lower shell.

[0015] Preferably, the discharge voltage test bench is a closed container, and atmospheric pressure is applied to the lower shell through an air pressure inlet on the top wall.

[0016] Preferably, a support plate is fixedly connected to the outer side of the lower shell, and the support plate is pressed onto the inner annular surface of the bottom opening of the discharge voltage test bench.

[0017] Preferably, the support plate is welded to the outer side of the lower shell by argon arc welding, one side of the support plate abuts against a stop A on the outer side of the lower shell, and the other side of the support plate is crimped onto the inner annular surface of the bottom opening of the discharge voltage test bench.

[0018] The present application reduces the risk of insulator breakage during assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of a preferred embodiment of an existing test fixture.

[0020] Figure 2 Give basis Figure 1 The test fixture shown is a schematic diagram of a discharge voltage test.

[0021] Figure 3 It is a structural schematic diagram of a preferred embodiment of the discharge voltage test fixture under air pressure for preventing the insulator from breaking.

[0022] Figure 4 This application Figure 3 Schematic diagram of the test fixture of the illustrated embodiment being assembled on a discharge voltage test bench for testing.

[0023] Among them, 1-original upper shell, 2-original center electrode, 3-original side electrode, 4-original support plate, 5-original connecting rod, 6-original insulating bushing, 7-original lower shell, 8-insulator, 9-rubber ring, 11-upper shell, 12-center electrode, 13-side electrode, 14-support plate, 15-connecting rod, 16-insulating bushing, 17-lower shell. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the implementation of this application clearer, the technical scheme in the implementation of this application will be described in more detail in combination with the drawings in the implementation of this application. In the drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described implementation is a part of the implementation of this application, not all of the implementations. The implementation described below with reference to the drawings is exemplary and is intended to be used to explain this application, and cannot be understood as a limitation on this application. Based on the implementation in this application, all other implementations obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The implementation of this application is described in detail below in combination with the drawings.

[0025] refer to Figure 1 and Figure 2 The problem with the current special test fixture is that the insulator 8 breaks when the minimum discharge voltage is tested under air pressure. The reason is that the weakest part of the insulator 8 is squeezed twice during the assembly process. One time is when the insulator 8 is installed in the special test fixture, which is a normal force. The other time is when the special test fixture is installed on the minimum discharge voltage test bench, which is an abnormal squeeze, causing part of the insulator 8 to break.

[0026] The present application provides a discharge voltage test fixture under air pressure to prevent the insulator from breaking. The insulator 8 is a hollow structure, which includes a head and a tail. The outer diameter of the head is larger than the outer diameter of the tail, and a step is formed between the head and the tail. Figure 3 , the test fixture comprises:

[0027] The lower shell 17 is a hollow cylinder structure, fixed in the discharge voltage test bench, the top of the cylinder is provided with an internal thread on the inner wall surface, and the top of the cylinder has an annular extrusion surface D;

[0028] The upper shell 11 has external threads and is assembled on the top of the cylinder of the lower shell 17 through threaded connection;

[0029] An insulating bushing 16 is disposed in the lower housing 17, and the top of the insulating bushing has a top connection surface C, and the center of the insulating bushing has a receiving space;

[0030] The rubber ring 9 is arranged between the top extrusion surface D of the lower housing 17 and the top wall of the discharge voltage test bench;

[0031] The outer side of the head of the insulator 8 is a conical surface, and a side electrode 13 is sleeved thereon. A central electrode 12 is installed at the center of the insulator 8. The central electrode 12 is connected to a connecting rod 15 at the tail end of the insulator 8. The connecting rod 15 extends to the outside of the discharge voltage test bench through the accommodating space of the insulating bushing 16. The top connection surface C of the insulating bushing 16 is pressed from bottom to top on the step of the insulator 8, and the bottom end surface of the upper shell 11 is pressed from top to bottom on the side electrode 13 of the head of the insulator 8, thereby fixing the insulator 8 in the lower shell.

[0032] In order to solve the problem of insulator 8 breaking, the present invention first adjusts the force position of insulator 8 to the part with the largest wall thickness of insulator 8 (i.e. Figure 3 At the top connection surface C in the middle), the risk of the insulator 8 being broken during assembly is reduced. At the same time, the upper shell 11 is changed into an internal thread, the outer diameter of the upper shell 11 is reduced, and a gap is formed between the inner wall of the rubber ring 9 and the outer diameter of the upper shell 11. When the test fixture of the present application is assembled on the minimum discharge voltage test bench, the rubber ring 9 will not generate a force on the upper shell 11, but the force will be loaded on the lower shell 17 (i.e. Figure 3 at the extrusion surface D in the middle).

[0033] In the present application, the stress-bearing position of the insulator 8 during assembly is not at the weakest point of the insulator 8, and the insulator 8 is prevented from being subjected to secondary extrusion, thereby solving the problem of the insulator 8 being broken during the discharge voltage test under air pressure, improving the pass rate of the insulator 8 in the test process, reducing the quality risks of the semiconductor nozzle, and improving the working reliability of the semiconductor nozzle.

[0034] The present application discloses a pressure-discharge voltage test fixture for preventing the insulator from being broken. The original insulating bushing 6 material is changed from alumina ceramic to bakelite, and the sealant is eliminated, while a tight fit and extrusion seal is adopted. The insulator 8 is supported by an insulating bushing 16 (bakelite) instead of the original connecting rod 5 (stainless steel), so that the insulator 8 has a buffering and elastic force. In addition, the rubber ring 9 no longer acts on the upper shell 11, so that the insulator 8 is no longer subjected to secondary extrusion. In this way, after the performance of the insulator 8 is tested by the pressure-discharge voltage test fixture of the present application, the insulator 8 no longer breaks, thereby improving the test pass rate of the insulator 8.

[0035] In some optional embodiments, a portion of the upper shell 11 exposed outside the lower shell 17 is clearance-fitted with the rubber ring 9 .

[0036] In some optional embodiments, the insulating bushing 16 is made of bakelite.

[0037] In some optional embodiments, the bottom end of the cylinder of the lower shell 17 has an inwardly contracted annular step, and the insulating bushing 16 includes a first cylinder with a larger outer diameter and a second cylinder with a smaller outer diameter, an extrusion step is formed between the first cylinder and the second cylinder, the first cylinder is located in the lower shell 17, the extrusion step is squeezed on the inner wall surface B of the annular step of the lower shell 17, and the second cylinder passes through the annular step of the lower shell 17 and extends out of the lower shell 17.

[0038] In some optional embodiments, the discharge voltage test bench is a closed container, and atmospheric pressure is applied to the lower shell 17 through an air pressure inlet on the top wall.

[0039] In some optional implementations, a support plate 14 is fixedly connected to the outer side of the lower shell 17 , and the support plate 14 is crimped onto the inner annular surface of the bottom opening of the discharge voltage test bench.

[0040] The lower shell 17 of the present application is welded with the support plate 14 by argon arc welding and installed on the minimum discharge voltage test bench. Figure 4 As shown, when the upper shell 11 is tightened, the upper shell 11 and the lower shell 17 will not squeeze the insulator, thereby preventing the insulator 8 from being stressed again and breaking.

[0041] In some optional embodiments, the support plate 14 is welded to the outside of the lower shell 17 by argon arc welding, one side of the support plate 14 abuts against a stop A on the outside of the lower shell 17, and the other side of the support plate 14 is crimped onto the inner annular surface of the bottom opening of the discharge voltage test bench.

[0042] refer to Figure 2 and Figure 4 , the main differences between the two test fixtures:

[0043] a. When assembled on the discharge voltage test bench, the original dedicated test fixture will generate secondary pressure on the insulator 8, causing the insulator 8 to break, while the test fixture of the present application will not generate secondary pressure, and the insulator 8 will not break.

[0044] b. The clamp of the present application has two inner and outer steps due to the lower housing 17 ( Figure 4 The two steps block and fix all parts to prevent the internal parts of the fixture from loosening and rushing out of the fixture when the airtight device is tightened and the air pressure increases. Therefore, the test fixture of the present invention is safer to use.

[0045] c. Due to the difference in size and structure of the two test fixtures, the number of rubber rings 9 to be assembled will be different when they are installed on the test bench, as long as the air tightness of the assembly can be guaranteed.

[0046] This application follows the following steps to process the test fixture of this application:

[0047] 1. Use a stainless steel rod to process an upper shell 11.

[0048] 2. Use high temperature alloy GH3044 to process one center electrode 12 and one side electrode 13.

[0049] 3. One support plate 14 and one connecting rod 15 are respectively processed from stainless steel.

[0050] 4. Use bakelite stick to process an insulating bushing 16.

[0051] 5. Use stainless steel to process the lower housing 17.

[0052] 6. Use a rubber rod to process multiple rubber rings 9. The thickness of the rubber ring 9 can be adjusted according to the airtightness effect of the assembly.

[0053] 7. Sleeve the support plate 14 onto the outer step of the lower shell 17, and weld the two parts together using argon arc welding.

[0054] 8. Pass the small outer round end of the connecting rod 15 through the large hole end of the insulating bushing 16 and press it tightly to ensure sealing.

[0055] 9. Insert the insulating bushing 16 (including the connecting rod 15) into the lower housing 17 and press it tightly to ensure sealing.

[0056] 10. Put the insulator 8 on the center electrode 12, then tighten the center electrode 12 to the connecting rod 15, put the side electrode 13 on the conical surface of the insulator 8, and finally tighten the upper shell 11 to the lower shell 17. Put several rubber rings 9 on the upper shell 11 to ensure that there is no air leakage when assembled on the discharge voltage test bench.

[0057] The test fixture of the present invention processed by this process tested the minimum discharge voltage of 50 insulator parts under 1MPa pressure, and no insulator fragmentation occurred. The test results were verified to be accurate and reliable, with a qualified rate of 100%.

[0058] Although the present application has been described in detail above with general descriptions and specific implementation schemes, it is obvious to those skilled in the art that some modifications or improvements may be made to the present application. Therefore, these modifications or improvements made without departing from the spirit of the present application all fall within the scope of protection claimed in the present application.

Claims

1. A discharge voltage test fixture under air pressure to prevent the insulator from breaking, wherein the insulator (8) is a hollow structure, comprising a head and a tail, the outer diameter of the head is larger than the outer diameter of the tail, and a step is formed between the head and the tail, characterized in that: The test fixture comprises: The lower shell (17) is a hollow cylinder structure, fixed in the discharge voltage test bench, the top of the cylinder is provided with an internal thread on the inner wall surface, and the top of the cylinder has an annular extrusion surface D; The upper shell (11) has an external thread and is assembled on the top of the cylinder of the lower shell (17) through a threaded connection; An insulating bushing (16) is arranged in the lower housing (17), and the top end of the insulating bushing has a top connection surface C, and the center of the insulating bushing has a containing space; The rubber ring (9) is arranged between the top extrusion surface D of the lower housing (17) and the top wall of the discharge voltage test bench; The outer side of the head of the insulator (8) is a conical surface and is sleeved with a side electrode (13). A central electrode (12) is installed at the center of the insulator (8). The central electrode (12) is connected to a connecting rod (15) at the tail end of the insulator (8). The connecting rod (15) extends to the outside of the discharge voltage test bench through the accommodating space of the insulating bushing (16). The top connection surface C of the insulating bushing (16) is pressed from bottom to top on the step where the wall thickness of the insulator (8) is the largest. The bottom end surface of the upper shell (11) is pressed from top to bottom on the side electrode (13) at the head of the insulator (8), thereby fixing the insulator (8) in the lower shell.

2. The discharge voltage test fixture under air pressure for preventing the insulator from breaking as claimed in claim 1, characterized in that: A portion of the upper shell (11) exposed outside the lower shell (17) and the rubber ring (9) are clearance-fitted.

3. The discharge voltage test fixture under air pressure to prevent insulator fragmentation as claimed in claim 1, characterized in that: The insulating bushing (16) is made of bakelite.

4. The discharge voltage test fixture under air pressure for preventing insulator from breaking as claimed in claim 1, characterized in that: The bottom end of the cylinder of the lower shell (17) has an annular step that contracts inwardly, and the insulating bushing (16) includes a first column with a larger outer diameter and a second column with a smaller outer diameter, an extrusion step is formed between the first column and the second column, the first column is located in the lower shell (17), the extrusion step is squeezed on the inner wall surface B of the annular step of the lower shell (17), and the second column passes through the annular step of the lower shell (17) and extends out of the lower shell (17).

5. The discharge voltage test fixture under gas pressure to prevent insulator fragmentation as claimed in claim 1, characterized in that: The discharge voltage test bench is a closed container, and atmospheric pressure is applied to the lower shell (17) through the air pressure inlet on the top wall.

6. The discharge voltage test fixture under gas pressure to prevent insulator fracture as claimed in claim 1, characterized in that: A support plate (14) is fixedly connected to the outer side of the lower shell (17), and the support plate (14) is pressed onto the inner ring surface of the bottom opening of the discharge voltage test bench.

7. The discharge voltage test fixture under gas pressure for preventing insulator from breaking as claimed in claim 6, characterized in that: The support plate (14) is welded to the outside of the lower shell (17) by argon arc welding, one side of the support plate (14) abuts against a stop A on the outside of the lower shell (17), and the other side of the support plate (14) is pressed against the inner ring surface of the bottom opening of the discharge voltage test bench.

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