High-temperature heavy-load low-speed working condition aircraft tail nozzle multi-movement pair wear test fixture device

Abstract

This invention provides a wear testing fixture for multiple kinematic pairs of aircraft tail nozzles under high-temperature, heavy-load, and low-speed operating conditions. The fixture consists of a fixture base and a lower fixture module mounted at both ends of the test workpiece. The fixture base includes a support seat and a replaceable clamping device detachably mounted on the support seat. The replaceable clamping device is rotatably connected to the test workpiece via a rotating shaft. The lower fixture module is rotatably connected to the test workpiece via a rotating shaft or a ball joint. A CrN-CrAlN coating is provided on the friction surfaces of the replaceable clamping device and the lower fixture module that contact the test workpiece. A method for preparing the CrN-CrAlN coating is also disclosed. This wear testing fixture uses a replaceable clamping device to meet the clamping requirements of test workpieces of different sizes and with different motion patterns. The workpiece in the lower fixture module can be connected via a rotating shaft or a ball joint, enabling wear testing of rotating pairs and ball-and-socket joints of the workpiece.

Description

Technical Field

[0001] This invention relates to the field of wear testing equipment technology, specifically to a wear testing fixture for multiple moving parts of an aircraft tail nozzle under high temperature, heavy load, and low speed conditions. Background Technology

[0002] In recent years, the high-performance requirements of a new batch of engineering projects in my country's aerospace, nuclear industry, and other cutting-edge defense technologies have subjected moving mechanisms to extreme conditions such as high temperatures and heavy loads for extended periods. This can easily lead to performance degradation or even failure of key moving parts, thereby limiting the overall performance, lifespan, and reliability of equipment systems, and even causing major engineering disasters. To clarify the tribological performance degradation mechanism of moving components and optimize the tribological design of surface interfaces, it is urgent to develop a high-temperature, heavy-load simulated working condition tribological testing system to fill the gap in testing instruments in this field. Existing rotary joint fixtures lack targeted high-temperature wear-resistant surface design, resulting in easy oxidation and reduced thermal hardness of the contact surface at temperatures above 500°C, leading to rapid wear and low lifespan, making them unsuitable for high-temperature, heavy-load friction and wear tests. For tribological testing systems under special working conditions, a detachable and replaceable moving part wear testing fixture needs to be designed to ensure stability and data reliability during the wear testing process.

[0003] Chinese patent document CN113310787A discloses a multifunctional friction and wear testing device under a controllable and stable magnetic field environment. The lower clamp of the device is fixedly connected to the reciprocating platform and is only suitable for friction and wear testing of a single kinematic pair. Furthermore, the testing device is not optimized for high temperature and heavy load conditions, resulting in a low service life under such conditions. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a fixture device for testing the wear of multiple moving parts of an aircraft tail nozzle under high temperature, heavy load, and low speed conditions.

[0005] According to the present invention, a high-temperature, heavy-load, low-speed aircraft tail nozzle multi-motion pair wear test fixture device includes: a fixture base and a lower fixture module respectively installed at both ends of the test workpiece;

[0006] The fixture base includes a support base and a replaceable clamping device that is detachably mounted on the support base. The replaceable clamping device is rotatably connected to the test workpiece via a rotating shaft. The lower fixture module is rotatably connected to the test workpiece via a rotating shaft or via a ball joint.

[0007] The replaceable clamping device and the lower clamping module have a CrN-CrAlN coating on the friction surfaces that come into contact with the test workpiece.

[0008] Preferably, the support base is provided with multiple mounting holes and mounting slots, and the replaceable clamping device can be embedded in the mounting slots and fixed in the mounting holes by bolts.

[0009] Preferably, the replaceable clamping device includes a hinged support, on which a rotating connection hole is provided. The test workpiece is rotatably connected to the hinged support through a pin passing through the rotating connection hole, and a washer is fixed to one end of the pin.

[0010] The lower clamping module includes a U-shaped clamping head, which has a rotating connection hole. The test workpiece is rotatably connected to the U-shaped clamping head through a pin inserted in the rotating connection hole.

[0011] Preferably, the fixture base and the lower fixture module are used to connect the roller cam workpiece;

[0012] The clamp base is connected to the cam; the lower clamp module is connected to the cam, and the cam makes rolling contact with the roller.

[0013] Preferably, the replaceable clamping device includes a hinged support, on which a rotating connection hole is provided. The test workpiece is rotatably connected to the hinged support through a tie rod pin passing through the rotating connection hole, and a pin retainer is fixed at the end of the tie rod pin.

[0014] The lower clamp module includes a pair of ear plates, a ball socket, and a ball socket pin. The ear plates have a rotating connection hole. The ball socket is located between the pair of ear plates. The ball socket pin passes through the ear plates and the ball socket respectively. The test workpiece is rotated and sleeved on the ball socket.

[0015] Preferably, the clamp base and the lower clamp module are used to connect the tripod;

[0016] The clamp base is rotatably connected to one end of the tripod via a rotating shaft, and the lower clamp module is rotatably connected to the other end of the tripod via a ball joint.

[0017] Preferably, the replaceable clamping device and the lower clamping module are made of GH2747 alloy, and the rotating connection hole of the replaceable clamping device and the lower clamping module is provided with grooves along the circumferential direction on the wall.

[0018] Preferably, the trench is generated through the following steps:

[0019] A1. Roughly machine the contact surface, turn the rotating connection hole of the fixture, and bore the circumferential groove in the hole. The machining accuracy is 15μm and the surface roughness is Ra0.8.

[0020] A2. The contact surface is precision machined, and the circumferential groove structure is precision bored to a surface roughness of Ra0.08. The connecting surface is mirror ground to a surface roughness of Ra0.01.

[0021] Preferably, the CrN-CrAlN coating is formed in the following manner:

[0022] Step S1: Surface cleaning. Spray the detergent at 50℃ for 10 minutes to remove surface oil stains. Then place it in deionized water for ultrasonic cleaning at room temperature for 5 minutes. After air drying, sandblast clean at room temperature for 15 minutes. Place it in anhydrous ethanol for cleaning at room temperature for 5 minutes. After air drying, place it in N2 atmosphere for plasma cleaning.

[0023] Step S2: Vacuum drying. Place the fixture in the vacuum chamber and maintain a vacuum of 1 Pa for 20 minutes to ensure the fixture surface is dry.

[0024] Step S3: Coating preparation, maintaining a vacuum level of less than 5 x 10⁻⁶ in the vacuum chamber. -3 Pa, the surface of the fixture contact surface is sputtered and cleaned by bombarding with high-energy Ar+ particles. The negative bias voltage of the fixture is controlled between -40V and 160V using cathode arc evaporation technology, the cavity temperature is maintained at 400℃, and 99.99% high-purity N2 is introduced. First, a CrN coating with a thickness of 0.5μm-0.7μm is prepared by depositing Cr target material for 20min as a base layer. On the base layer, a CrAl target material is used to deposit CrAlN coating with a thickness of 1.5-3μm for 40min.

[0025] Preferably, the replaceable clamping device includes a base with a height of 12mm, and the depth of the mounting groove is 8mm lower than the height of the base.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The wear test fixture device disclosed in this invention adopts a replaceable clamping device to meet the clamping requirements of test workpieces of different sizes and different motion forms. The workpiece of the lower clamping module can be connected by rotating shaft or ball joint, realizing wear test of workpiece rotating pair and ball joint.

[0028] 2. The CrN-CrAlN coating applied to the friction surfaces of the replaceable clamping device and the lower clamping module in contact with the test workpiece exhibits excellent performance characteristics, including high hardness, good high-temperature thermodynamic properties, good oxidation resistance, and good low-speed wear resistance, thereby improving wear resistance under high-temperature and heavy-load conditions.

[0029] 3. The grooves provided on the wall of the rotating connection hole in this invention can facilitate the guidance of abrasive debris into the grooves, reducing abrasive wear with the surface coating and thus improving the life of the fixture coating.

[0030] Other beneficial effects of the present invention will be explained in detail through the introduction of specific technical features and technical solutions in specific embodiments. Those skilled in the art should be able to understand the beneficial technical effects brought about by these technical features and technical solutions through the introduction of these technical features and technical solutions. Attached Figure Description

[0031] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0032] Figure 1 This is a schematic diagram of the multi-moving-pair wear test fixture device in this invention;

[0033] Figure 2 This is a schematic diagram of the support structure in this invention;

[0034] Figure 3 This is a schematic diagram of the replaceable clamping device structure in this invention;

[0035] Figure 4 This is a schematic diagram of the roller cam pair wear test fixture in this invention;

[0036] Figure 5 This is a schematic diagram of the lower fixture module in the roller cam pair wear test fixture of the present invention;

[0037] Figure 6 This is a schematic diagram of the ball-rotating pair wear test fixture of the present invention;

[0038] Figure 7 This is a schematic diagram of the contact surface of the fixture in this invention.

[0039] Explanation of reference numerals in the attached figures:

[0040] Fixture base 1 Nut 23

[0041] Support 11, Bushing 24

[0042] Mounting hole 110, lower clamp pin 25

[0043] Mounting slot 111 Lower clamp washer 26

[0044] Replaceable clamping device 12, ear plate seat 51

[0045] Pin 13, socket 52

[0046] Washer 14, Socket pin 53

[0047] Hex bolt 15, ball socket washer 54

[0048] Tie rod pin 16, ball socket pin 55

[0049] Pin snap ring 17 Cam 3

[0050] Lower clamping module 2, roller 4

[0051] U-shaped clamp head 21 tripod 6

[0052] Screw 22 Detailed Implementation

[0053] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0054] This invention provides a test fixture for wear of multiple moving parts of an aircraft tail nozzle under high temperature, heavy load, and low speed conditions, with reference to... Figures 1-3 As shown, it includes: a clamp base 1 and a lower clamp module 2 respectively installed at both ends of the test workpiece; the clamp base 1 includes a support base 11 and a replaceable clamping device 12 detachably installed on the support base 11, the replaceable clamping device 12 is rotatably connected to the test workpiece via a rotating shaft, and the lower clamp module 2 is rotatably connected to the test workpiece via a rotating shaft or via a ball joint; the friction surfaces of the replaceable clamping device 12 and the lower clamp module 2 that contact the test workpiece are provided with a CrN-CrAlN coating.

[0055] The support base is provided with multiple mounting holes 110 and mounting grooves 111. The replaceable clamping device 12 can be embedded in the mounting groove 111 and fixed in the mounting hole 110 by hexagonal threaded bolts 15. The base height of the replaceable clamping device 12 is 12mm, and the depth of the mounting groove 111 is about 8mm lower than the plane of the clamp base 1, ensuring that most of the replaceable clamping part is installed in the mounting groove 111, ensuring a firm clamping.

[0056] The structure of the fixture is described below according to the type of workpiece being tested:

[0057] 1) For the wear test fixture of roller cam pairs, refer to Figure 4 and Figure 5 As shown, the test workpiece is connected to the replaceable clamping device 12 and the lower clamping module 2 via a rotating shaft. The clamping base 1 and one of the lower clamping modules 2 are respectively connected to both ends of the cam, and the other lower clamping module 2 is connected to the roller.

[0058] The replaceable clamping device 12 includes a hinged support with a rotating connection hole. The test workpiece is rotatably connected to the hinged support via a pin 13 passing through the rotating connection hole. Washers 14 are fixed to both ends of the pin 13. The inner diameter of the washer 14 is about 0.5 mm larger than the inner diameter of the pin 13 to increase the contact area of ​​the pin 13, thereby reducing pressure concentration on the surface of the pin 13 and preventing damage.

[0059] The lower clamp module 2, connected to the cam, includes a U-shaped clamp head 21. The U-shaped clamp head 21 has a rotating connection hole. The test workpiece is rotatably connected to the U-shaped clamp head 21 via a lower clamp pin 25 passing through the rotating connection hole. The inner distance of the U-shaped clamp head 21 is equal to the width of the cam. The lower clamp pin 25 is inserted into the U-shaped clamp head 21 and the cam, allowing them to rotate relative to each other. A lower clamp washer 26 is fixed to one side of the lower clamp pin 25.

[0060] The lower clamp connected to the roller includes a nut 23, a screw 22, and a bushing 24. The bushing 24 is fitted onto the screw 22. The bushing is coaxial with the inner diameter of the roller. The nut 23 can be fixed to one end of the screw 22 for easy positioning and disassembly.

[0061] 2) For the wear test fixture of the ball joint, refer to Figure 6 As shown, the test workpiece is a tripod 6. One end of the tripod 6 is rotatably connected to the replaceable clamping device 12 via a rotating shaft, and the other end of the tripod 6 is rotatably connected to the lower clamping module 2 via a ball joint.

[0062] The replaceable device includes a hinged support with a rotating connection hole. The test workpiece is rotatably connected to the hinged support through a tie rod pin 16 passing through the rotating connection hole. A pin retainer 17 is fixed at the end of the tie rod pin 16.

[0063] The lower clamp module 2 includes a pair of ear plate seats 51, a ball socket 52, a ball socket pin 55, a ball socket washer 54, and a ball socket pin 55. The ear plate seats 51 have a rotating connection hole. The ball socket 52 is located between the pair of ear plate seats 51. The ball socket pin 55 and the ball socket pin 53 are respectively inserted into the ear plate seats 51 and the ball socket 52. The ball socket washer 54 is slidably fitted onto one side of the ball socket pin 55 and the ball socket pin 55. The ball socket pin 55 is inserted into the side of the ball socket pin 55 and the ball socket washer 54, facilitating assembly and disassembly. A connection hole is provided at one end of the test workpiece, and the ball socket 52 is built into the connection hole, allowing the test workpiece to rotate in multiple directions via the ball socket 52.

[0064] Reference Figure 7As shown, the base material of the detachable clamping device and the lower clamping module 2 in this device is high-temperature alloy GH2747. Grooves are provided circumferentially on the walls of the rotating connection holes of the detachable clamping device and the lower clamping module 2. The grooves are 0.2mm deep and 0.2mm wide, which facilitates the guidance of abrasive debris into the grooves, reducing abrasive wear with the surface coating and thus improving the life of the clamping coating. The surface has a CrN-CrAlN high-temperature stable oxidation-resistant and wear-resistant coating with a tetragonal grain structure. Under experimental conditions of 800℃ high-temperature environment and 1Hz low-frequency reciprocating motion, it exhibits oxidation resistance and wear resistance, which can improve the clamping life. The surface processing method of the contact surface includes the following steps:

[0065] Step S1: Roughly machine the contact surface, turn the rotating connection hole of the fixture, and bore the circumferential groove in the hole. The machining accuracy is 15μm and the surface roughness is Ra0.8.

[0066] Step S2: Finish the contact surface by precision boring the circumferential groove structure to a surface roughness of Ra0.08 and mirror grinding the connecting surface to a surface roughness of Ra0.01 to facilitate subsequent coating preparation.

[0067] Step S3: Surface cleaning. Spray the detergent at 50℃ for 10 minutes to remove surface oil stains, then place it in deionized water for ultrasonic cleaning at room temperature for 5 minutes. After air drying, sandblast clean at room temperature for 15 minutes, place it in anhydrous ethanol for cleaning at room temperature for 5 minutes, and after air drying, place it in N2 atmosphere for plasma cleaning.

[0068] Step S4: Vacuum drying. Place the fixture in the vacuum chamber and maintain a vacuum of 1 Pa for 20 minutes to ensure the fixture surface is dry.

[0069] Step S5: Coating preparation, maintaining a vacuum level of less than 5 x 10⁻⁶ in the vacuum chamber. -3 Pa, the surface of the fixture contact surface is sputtered and cleaned by bombarding with high-energy Ar+ particles. The negative bias voltage of the fixture is controlled between -40V and 160V using cathode arc evaporation technology, the cavity temperature is maintained at 400℃, and 99.99% high-purity N2 is introduced. First, a CrN coating with a thickness of 0.5μm-0.7μm is prepared by depositing Cr target material for 20min as a base layer. On the base layer, a CrAl target material is used to deposit CrAlN coating with a thickness of 1.5-3μm for 40min.

[0070] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0071] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A high-temperature heavy-load low-speed working condition aircraft exhaust nozzle multi-movement pair wear test fixture device, characterized in that, The utility model relates to a test fixture for connecting workpiece, comprising: a fixture base (1) and a lower fixture module (2) respectively installed at two ends of the test workpiece; the fixture base (1) comprises a support seat (11) and a replaceable clamping device (12) detachably installed on the support seat (11), the replaceable clamping device (12) is rotatably connected with the test workpiece through a rotating shaft, and the lower fixture module (2) is rotatably connected with the test workpiece through a rotating shaft or a ball joint; when the lower fixture module (2) is rotatably connected with the test workpiece through the ball joint, the test workpiece is rotated by rotating the fixture base; a CrN-CrAlN coating is arranged on the friction surface of the replaceable clamping device (12) and the lower fixture module (2) in contact with the test workpiece; the mounting structure of the replaceable clamping device (12) and the lower fixture module (2) comprises any one of the following modes: mode one: the replaceable clamping device (12) comprises a hinged support seat, a rotating connection hole is formed in the hinged support seat, the test workpiece is rotatably connected with the hinged support seat through a pin (13) arranged in the rotating connection hole, and a washer (14) is fixed to one end of the pin (13); the lower fixture module (2) comprises a U-shaped clamp head (21), a rotating connection hole is formed in the U-shaped clamp head (21), and the test workpiece is rotatably connected with the U-shaped clamp head (21) through a pin arranged in the rotating connection hole; the fixture base (1) and the lower fixture module (2) are used for connecting a roller cam workpiece, the roller cam workpiece comprises a cam (3) and a roller (4); the fixture base (1) is connected with the cam (3), the lower fixture module (2) is connected with the cam (3), and the cam (3) is in rolling contact with the roller (4); mode two: the replaceable clamping device (12) comprises a hinged support seat, a rotating connection hole is formed in the hinged support seat, the test workpiece is rotatably connected with the hinged support seat through a pull rod pin (16) arranged in the rotating connection hole, and a pin spring (17) is fixed to the end of the pull rod pin (16); the lower fixture module (2) comprises a pair of ear plate seats (51), a ball socket (52) and a ball socket pin (53), a rotating connection hole is formed in the ear plate seat (51), the ball socket (52) is located between the pair of ear plate seats (51), the ball socket pin (53) is arranged in the ear plate seat (51) and the ball socket (52) respectively, and the test workpiece is rotatably sleeved on the ball socket (52); the fixture base (1) and the lower fixture module (2) are used for connecting a tripod (6); the fixture base (1) is rotatably connected with one end of the tripod (6) through a rotating shaft, and the lower fixture module (2) is rotatably connected with the other end of the tripod (6) through a ball joint.

2. The high-temperature heavy-load low-speed working condition aeronautical tail nozzle multi-movement pair wear test fixture device according to claim 1, characterized in that, a plurality of mounting holes (110) and mounting grooves (111) are arranged on the support seat (11), the replaceable clamping device (12) can be embeddedly installed in the mounting groove (111) and fixed in the mounting hole (110) through a bolt.

3. The high-temperature heavy-load low-speed operating condition aeronautical tail nozzle multi-movement pair wear test fixture device according to claim 1, characterized in that, The replaceable clamping device (12) and the lower clamp module (2) are made of GH2747 alloy material, and a groove is arranged on the rotating connecting hole wall of the replaceable clamping device (12) and the lower clamp module (2) in the circumferential direction.

4. The high-temperature heavy-load low-speed operating condition aeronautical tail nozzle multi-movement pair wear test fixture device according to claim 3, characterized in that, The groove is generated by the following steps: A1, roughen the contact surface, turn the clamping rotating connecting hole, bore the circumferential groove in the hole, the machining precision is 15 mu m, and the surface roughness Ra is 0.8; A2, finish the contact surface, finish the circumferential groove structure with a surface roughness Ra of 0.08, and mirror grind the connecting surface with a surface roughness Ra of 0.

01.

5. The high-temperature heavy-load low-speed operating condition aeronautical tail nozzle multi-movement pair wear test fixture device according to claim 3, characterized in that, The CrN-CrAlN coating is generated by the following ways: Step S1: surface cleaning, temperature 50 DEG C, under the condition of dirt remover spray cleaning 10 min to remove surface oil stain, then placed in deionized water, room temperature ultrasonic cleaning 5 min, after natural drying, room temperature sand blasting cleaning 15 min, placed in anhydrous ethanol, room temperature cleaning 5 min, after natural drying, placed in N2 atmosphere, plasma cleaning surface; Step S2: vacuum drying, the clamp is placed in the vacuum cavity, the vacuum degree is 1 Pa, and the clamp surface is dried for 20 min; Step S3: coating preparation, keeping the vacuum degree of the vacuum chamber less than 5x10 -3 Pa, using high-energy Ar+ particle bombardment to sputter clean the surface of the clamp contact surface, using cathodic arc evaporation technology, controlling the negative bias of the clamp at -40V to 160V, keeping the temperature in the chamber at 400℃, and introducing 99.99% high-purity N2, first using a Cr target to deposit a CrN coating with a thickness of 0.5-0.7μm as a bottom layer, and then using a CrAl target to deposit a CrAlN coating with a thickness of 1.5-3μm on the basis of the bottom layer.

6. The high-temperature heavy-load low-speed operating condition aeronautical tail nozzle multi-movement pair wear test fixture device according to claim 2, characterized in that, The replaceable clamping device (12) comprises a base, the height of the base is 12 mm, and the groove depth of the mounting groove (111) is 8 mm lower than the height of the base.

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