Dewar structure, vibration test device and vibration test method

Abstract

The invention provides a Dewar structure, a vibration test device and a vibration test method.The Dewar structure comprises an outer cylinder, an inner cylinder and a cover plate, the outer bottom of the outer cylinder is connected with an outer cylinder flange, the top of the inner cylinder is connected with the top of the outer cylinder, a vacuum cavity is formed between the outer wall of the inner cylinder and the inner wall of the outer cylinder, and a clamping assembly is arranged in the inner cylinder and used for clamping a to-be-tested piece; a temperature sensor and a heating device are further arranged in the inner cylinder; the cover plate is detachably connected to the tops of the outer cylinder and the inner cylinder and provided with a liquid conveying opening and an exhaust opening. The Dewar structure is connected to a vibration table through an outer cylinder flange to form a vibration test box, a low-temperature working medium is input through a liquid conveying opening in a cover plate to evaporate and absorb heat to reduce the temperature in the inner cylinder so as to meet the extreme low-temperature requirement, and the temperature in the inner cylinder is increased through heating of a heating device so as to meet the extreme high-temperature requirement. Temperature monitoring is carried out based on the temperature sensor, accurate temperature control in a vibration test is achieved, and the requirement of a test piece to be tested for an extreme temperature environment is met.

Description

Technical Field

[0001] The invention relates to the technical field of vibration testing, and in particular to a dewar structure, a vibration testing device and a vibration testing method. Background Art

[0002] Civilian electrical and electronic products, automobile and aircraft parts, and various components in rockets and aerospace vehicles will encounter periodic or random vibrations during production, manufacturing, transportation and use. Therefore, vibration tests such as modal tests and vibration resistance tests are required to determine the structural strength, fatigue strength and working performance of the test pieces before formal use.

[0003] For some test pieces with extreme working environments, such as aerospace product test pieces, vibration conditions may occur in complex environments. For example, in the lunar exploration project, the lander is in an ultra-high vacuum on the lunar surface, with a temperature of 127°C during the day and -183°C at night. Under this large temperature difference between day and night, various vibration conditions will be encountered. In order to fully test the performance of the above product test pieces when in service, it is necessary to simulate the natural environment in which the above products are working and provide a vibration test chamber that can achieve rapid temperature rise and fall and temperature control.

[0004] The existing vibration test chamber cannot meet the test requirements of the test specimens in extreme temperature environments, especially in extreme low temperature environments. Summary of the invention

[0005] The present invention provides a dewar structure, a vibration test device and a vibration test method, which are used to solve the defect that a conventional vibration test chamber in the prior art cannot meet the requirements of a test piece to be tested on an extreme temperature environment.

[0006] On one hand, the present invention provides a Dewar structure, comprising an outer cylinder, an inner cylinder and a cover plate, wherein the outer bottom of the outer cylinder is connected to the outer cylinder flange, and the outer cylinder flange is used to connect to a vibration table; the inner cylinder is arranged in the outer cylinder, the top of the inner cylinder is connected to the top of the outer cylinder, a vacuum cavity is formed between the outer wall of the inner cylinder and the inner wall of the outer cylinder, a clamping assembly is arranged in the inner cylinder, the clamping assembly is used to clamp a piece to be tested, and a temperature sensor and a heating device are also arranged in the inner cylinder; the cover plate is detachably connected to the outer cylinder and the top of the inner cylinder, and an infusion port and an exhaust port are arranged on the cover plate.

[0007] According to a Dewar structure provided by the present invention, a support column is fixed to the inner bottom of the outer cylinder, the outer bottom of the inner cylinder is connected to the inner cylinder flange, and the support column is connected to the inner cylinder flange to rigidly fix the inner cylinder relative to the outer cylinder.

[0008] According to a Dewar structure provided by the present invention, a stirring mechanism is arranged in the inner cylinder, and the stirring mechanism is used for stirring to accelerate the heat exchange inside the inner cylinder.

[0009] According to a Dewar structure provided by the present invention, the stirring mechanism includes an axial flow fan, the axial flow fan is connected to the driving shaft, the driving shaft is rotatably mounted on the bearing seat, the bearing seat is passed through the cover plate, a power motor is arranged on the cover plate, the output shaft of the power motor is connected to the driving shaft through a coupling, and the outer cover of the power motor is provided with a motor protection cover.

[0010] According to a Dewar structure provided by the present invention, the exhaust port is a KF flange interface, and a solenoid valve is arranged in the infusion port; a handle and an aviation plug are symmetrically arranged on the cover plate, and the aviation plug is connected to the temperature sensor and the heating device.

[0011] According to a Dewar structure provided by the present invention, there are multiple temperature sensors, which are evenly installed on the bottom, side wall and surface of the test piece of the inner cylinder, and the heating device includes multiple heating rods, which are installed on the bottom of the inner cylinder and the surface of the test piece.

[0012] According to a Dewar structure provided by the present invention, the clamping assembly includes two clamping platforms arranged opposite to each other, the clamping platforms are fixed to the inner bottom of the inner tube, and clamping members are movably provided on the two clamping platforms. The clamping members on the two clamping platforms correspond to each other and are arranged opposite to each other, so as to clamp the test piece through the clamping members arranged opposite to each other.

[0013] According to a Dewar structure provided by the present invention, the clamping component is made of Invar alloy.

[0014] Another aspect of the present invention provides a vibration test device, comprising the Dewar structure described in any one of the above items and a vibration table, wherein the Dewar structure is fixed to the vibration table via an outer cylinder flange connection.

[0015] Another aspect of the present invention further provides a vibration test method, which is applicable to the above-mentioned vibration test device, and the vibration test method includes the following steps S1 to S4.

[0016] S1. Fix the test piece to the clamping assembly of the inner cylinder, cover the cover tightly, and fix the Dewar structure to the vibration table through the outer cylinder flange connection.

[0017] S2. Spray low-temperature working fluid into the inner cylinder through the infusion port on the cover plate, so that the low-temperature working fluid evaporates and absorbs heat to cool down in the inner cylinder. Connect the exhaust port on the cover plate to a gas collection system to collect the evaporated gaseous working fluid. Monitor the temperature of the test piece through a temperature sensor. When the temperature of the test piece reaches the low-temperature test temperature and the temperature is stable, adjust the spraying rate of the low-temperature working fluid to keep the test piece at the low-temperature test temperature. Start the vibration table to perform a low-temperature vibration performance test and record the low-temperature vibration test parameters.

[0018] S3. After the low-temperature vibration performance test is completed, stop spraying the low-temperature working fluid, use the heating device to heat the inner cylinder, monitor the temperature of the test piece through the temperature sensor, and when the temperature of the test piece reaches the high-temperature test temperature, adjust the heating power of the heating device to keep the test piece at the high-temperature test temperature, start the vibration table to perform the high-temperature vibration performance test, and record the high-temperature vibration test parameters.

[0019] S4. Change the low-temperature test temperature and the high-temperature test temperature in turn, and repeat the low-temperature vibration performance test at different low-temperature test temperatures and the high-temperature vibration performance test at different high-temperature test temperatures respectively. After the test is completed, take out the test piece, observe and record the appearance data of the test piece, and complete the vibration test.

[0020] The present invention provides a dewar structure, a vibration test device and a vibration test method. The outer cylinder, the inner cylinder and the cover plate form a dewar structure. The dewar structure is connected to a vibration table through the outer cylinder flange at the outer bottom of the outer cylinder to form a vibration test box. The low-temperature working fluid is input through the infusion port on the cover plate to evaporate and absorb heat to reduce the internal temperature of the inner cylinder to meet the extreme low temperature requirements. The internal temperature of the inner cylinder is increased by heating through a heating device to meet the extreme high temperature requirements. The temperature is monitored based on a temperature sensor to achieve precise control of the temperature in the vibration test. The present invention forms a vibration test box by connecting the dewar structure to the vibration table. The precise control of the internal temperature of the inner cylinder can meet the requirements of the test piece for the extreme temperature environment, and realize the vibration test within the temperature range of -233~200℃. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a schematic diagram of the internal structure of the Dewar structure provided by the present invention.

[0023] Figure 2 It is an axonometric structural schematic diagram of the Dewar structure provided by the present invention.

[0024] Figure 3 It is a schematic diagram of the explosion structure of the Dewar structure provided by the present invention.

[0025] Figure numerals: 1. outer cylinder; 2. outer cylinder flange; 3. inner cylinder; 4. clamping assembly; 5. temperature sensor; 6. heating device; 7. cover plate; 8. infusion port; 9. exhaust port; 10. support column; 11. inner cylinder flange; 12. axial flow fan; 13. drive shaft; 14. bearing seat; 15. power motor; 16. coupling; 17. motor protection cover; 18. handle; 19. aviation plug; 20. test piece. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0028] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0029] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0030] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0031] Combine the following Figures 1 to 3 The present invention describes the dewar structure, vibration test device and vibration test method.

[0032] One embodiment of the present invention provides a Dewar structure, combined with Figure 1 and Figure 3 As shown, the Dewar structure includes an outer tube 1, an inner tube 3 and a cover plate 7, wherein the outer bottom of the outer tube 1 is connected to the outer tube flange 2, and the outer tube flange 2 is used to connect to the vibration table; the inner tube 3 is arranged in the outer tube 1, the top of the inner tube 3 is connected to the top of the outer tube 1, and a vacuum cavity is formed between the outer wall of the inner tube 3 and the inner wall of the outer tube 1, and a clamping assembly 4 is arranged in the inner tube 3, and the clamping assembly 4 is used to clamp the test piece, and a temperature sensor 5 and a heating device 6 are also arranged in the inner tube 3; the cover plate 7 is detachably connected to the outer tube 1 and the top of the inner tube 3, and an infusion port 8 and an exhaust port 9 are arranged on the cover plate 7.

[0033] It can be understood that the Dewar structure of this embodiment can be connected to the vibration table through the outer tube flange 2 at the outer bottom of the outer tube 1 to form a vibration test chamber. The outer tube 1, the inner tube 3 and the cover plate 7 form a Dewar structure. The low-temperature working fluid is input through the infusion port 8 on the cover plate 7 to evaporate and absorb heat to reduce the internal temperature of the inner tube 3 to meet the extreme low temperature requirements. The heating device 6 is used to heat the internal temperature of the inner tube 3 to meet the extreme high temperature requirements. The temperature is monitored based on the temperature sensor 5 to achieve precise control of the temperature during the vibration test. The Dewar structure provided in this embodiment is connected to the vibration table to form a vibration test chamber. The precise control of the internal temperature of the inner tube 3 can meet the requirements of the test specimen for the extreme temperature environment and achieve a vibration test within the temperature range of -233~200℃.

[0034] In some embodiments of the Dewar structure of the present invention, see Figure 1As shown, a support column 10 is fixed to the inner bottom of the outer cylinder 1 , and the outer bottom of the inner cylinder 3 is connected to the inner cylinder flange 11 . The support column 10 is connected to the inner cylinder flange 11 , so that the inner cylinder 3 is rigidly fixed relative to the outer cylinder 1 .

[0035] In a conventional Dewar structure, the inner cylinder is in a suspended state, and the inner cylinder will shake during the vibration test. It can be understood that the Dewar structure in this embodiment is different from the conventional Dewar structure. In this embodiment, the inner and outer cylinders of the Dewar structure are rigidly connected by support columns 10, which ensures the high vacuum of the interlayer and enhances the stiffness of the Dewar, so that it can complete the test of the set vibration intensity under structural stability. In addition, the existence of the vacuum interlayer reduces heat leakage during the low-temperature vibration test and reduces the loss of low-temperature working fluid.

[0036] In some embodiments of the Dewar structure of the present invention, a stirring mechanism is provided in the inner cylinder 3, and the stirring mechanism is used to stir and accelerate the heat exchange inside the inner cylinder 3. In some specific examples, see again Figure 1 As shown, the stirring mechanism includes an axial flow fan 12, the axial flow fan 12 is connected to the driving shaft 13, the driving shaft 13 is rotatably mounted on the bearing seat 14, the bearing seat 14 is passed through the cover plate 7, and a power motor 15 is arranged on the cover plate 7. The output shaft of the power motor 15 is connected to the driving shaft 13 through a coupling 16, and a motor protection cover 17 is arranged on the outer cover of the power motor 15.

[0037] It is understandable that during the period of evaporation and cooling of the low-temperature working medium filled in the inner cylinder 3, and during the period of heating the inner cylinder 3 by the heating device 6 to increase the temperature inside the inner cylinder 3, the stirring mechanism in this example can accelerate the flow of air in the inner cylinder 3, achieve rapid heat exchange, enhance the uniformity of temperature distribution inside the inner cylinder 3, and make the temperature control accuracy higher. Specifically, the power motor 15 is started, and the rotational power is transmitted to the drive shaft 13 through the coupling 16. The drive shaft 13 rotates on the bearing seat 14, driving the axial flow fan 12 in the inner cylinder 3 to work. The rotation of the axial flow fan 12 accelerates the heat exchange inside the inner cylinder 3, making the temperature distribution more uniform.

[0038] The working intensity of the axial flow fan 12 needs to be related to the temperature in the inner tube 3. Based on the test temperature to be reached in the inner tube 3, the temperature in the inner tube 3 is monitored by the temperature sensor 5, and the working intensity of the axial flow fan 12 is adjusted according to the data monitored by the temperature sensor 5. It should be understood that in the process of low-temperature vibration performance testing, it is necessary to reduce the temperature in the inner tube 3, the flow rate of the low-temperature working fluid input by the temperature sensor 5 and the infusion port 8, the speed of the evaporation working fluid sucked by the exhaust port 9, and the working intensity of the axial flow fan 12 can all be controlled in a linkage manner through an automatic control program (such as LabView). In the process of high-temperature vibration performance testing, it is necessary to increase the temperature in the inner tube 3, and the temperature sensor 5, the heating device 6 and the working intensity of the axial flow fan 12 can also be controlled in a linkage manner through an automatic control program (such as LabView). Through the control of the automatic control program, the internal temperature of the Dewar structure can be changed according to the set heating and cooling rate and kept stable at a specific temperature.

[0039] In some embodiments of the Dewar structure of the present invention, the exhaust port 9 is a KF flange interface, and a solenoid valve is provided in the infusion port 8; during the low-temperature vibration performance test, the low-temperature working fluid filled in the inner tube 3 is evaporated and cooled. At this time, the exhaust port 9 of the KF flange interface is externally connected to a gas collection system, and the gas collection system provides exhaust for the inner tube 3 through the exhaust port 9 to discharge the evaporated low-temperature working fluid to maintain a certain air pressure and avoid excessive internal air pressure. During the high-temperature vibration performance test, it is necessary to increase the temperature inside the inner tube 3. While heating by the heating device 6, normal temperature or high-temperature and high-pressure nitrogen or helium can also be introduced into the inner tube 3 through the exhaust port 9, so that the temperature inside the inner tube 3 can be quickly increased.

[0040] For some specific examples, see Figure 2 As shown, the cover plate 7 is symmetrically provided with a handle 18 and an aviation plug 19, the aviation plug 19 connects the temperature sensor 5 and the heating device 6, and the aviation plug 19 realizes the electrical signal connection inside and outside the vacuum, and the data signal of the temperature sensor 5 and the control signal of the heating device 6 can be output and input through the aviation plug. The handle 18 is used to open or close the cover plate 7. If the size and weight of the overall equipment are too large, the handle 18 can be designed as a lifting ear to lift the cover plate 7 by a crane.

[0041] In the inner cylinder 3, multiple temperature sensors 5 can be provided. The temperature sensors 5 are used to monitor the ambient temperature in the inner cylinder 3 and the temperature of the test piece. The temperature sensors 5 can be installed at the bottom and side walls of the inner cylinder 3. After the test piece is loaded, the temperature sensors 5 also need to be fixed on the surface of the test piece. The heating device 6 is used to heat the internal ambient temperature of the inner cylinder 3 during the high-temperature vibration performance test. In some specific examples, the heating device 6 includes multiple heating rods, which are installed at the bottom of the inner cylinder 3 and the surface of the test piece to provide heat for low-temperature rewarming and high-temperature testing.

[0042] In some embodiments of the Dewar structure of the present invention, the clamping assembly 4 is made of Invar alloy, and the clamping assembly 4 includes two clamping tables arranged opposite to each other, the clamping tables are fixed to the bottom of the inner tube 3, and clamping members are movably provided on the two clamping tables. The clamping members on the two clamping tables correspond to each other and are arranged opposite to each other, so as to clamp the test piece through the clamping members arranged opposite to each other.

[0043] It is understandable that the clamping assembly 4 made of Invar alloy has an extremely low thermal expansion coefficient, which can ensure both the rigid connection strength with the inner tube 3 and the stability of fixing the test piece. When installing the test piece, the test piece is placed between the two clamping tables, and then the clamping members arranged opposite to each other on the two clamping tables are adjusted at the same time. The clamping members can be fastening bolts, and the test piece is clamped and fixed by the clamping members arranged opposite to each other.

[0044] Another aspect of the present invention provides a vibration test device. In some embodiments, the vibration test device includes the Dewar structure in any one of the above embodiments or examples, and also includes a vibration table. The Dewar structure is connected and fixed to the vibration table through an outer cylinder flange 2.

[0045] It can be understood that, since the vibration test device in this embodiment includes the above-mentioned Dewar structure, the vibration test device in this embodiment has the advantages of the above-mentioned Dewar structure. Through the vibration test device of this embodiment, the vibration test of the test piece in the extreme temperature range (-233~200℃) can be realized; the inner and outer cylinders of the Dewar are rigidly connected by multiple rigid support columns, which enhances the stiffness of the Dewar, and at the same time, combined with the vacuum cavity, low heat conduction between the inner and outer cylinders of the Dewar is realized.

[0046] Another aspect of the present invention provides a vibration test method, which is applicable to the vibration test device in the above embodiment. The vibration test method includes the following steps S1 to S4.

[0047] S1. Fix the test piece to the clamping assembly 4 of the inner cylinder 3, cover the cover plate 7, and connect and fix the Dewar structure to the vibration table through the outer cylinder flange 2.

[0048] Step S1 is the vibration test preparation stage. Before conducting the vibration test, the cover plate 7 is lifted by a crane, and the test piece 20 is installed on the clamping assembly 4 and clamped. After testing that each temperature sensor 5, solenoid valve, power motor 15, axial flow fan 12 and heating device 6 are working normally, the device cover plate 7 is closed tightly, and the assembled Dewar structure is placed on the vibration table as a whole, and connected to the vibration table through the holes of the outer cylinder flange 2 at the bottom to achieve the fixation of the Dewar structure and the vibration table.

[0049] S2. Spray the low-temperature working fluid into the inner tube 3 through the infusion port 8 on the cover plate 7, so that the low-temperature working fluid evaporates and absorbs heat and cools down in the inner tube 3. Connect the exhaust port 9 on the cover plate 7 to the gas collection system to collect the evaporated gaseous working fluid. Monitor the temperature of the test piece through the temperature sensor 5. When the temperature of the test piece reaches the low-temperature test temperature and the temperature is stable, adjust the spraying rate of the low-temperature working fluid to keep the test piece at the low-temperature test temperature. Start the vibration table to perform the low-temperature vibration performance test and record the low-temperature vibration test parameters.

[0050] Step S2 is the low-temperature vibration performance test stage. The power motor 15 is started to turn on the axial flow fan 12, and the temperature control program is started. The low-temperature working fluid is sprayed from the infusion port 8 into the inner tube 3 at the set cooling rate and under the flow control of the solenoid valve, and the internal environment of the inner tube 3 is quickly evaporated and cooled. The exhaust port 9 is connected to the gas collection system to avoid excessive air pressure inside the inner tube 3. The temperature sensor 5 monitors the temperature cooling rate of the test piece and starts the vibration test after the test temperature is stable.

[0051] S3. After the low-temperature vibration performance test is completed, stop spraying the low-temperature working fluid, heat up the inner tube 3 through the heating device 6, monitor the temperature of the test piece through the temperature sensor 5, and when the temperature of the test piece reaches the high-temperature test temperature, adjust the heating power of the heating device 6 to keep the test piece at the high-temperature test temperature, start the vibration table to perform the high-temperature vibration performance test, and record the high-temperature vibration test parameters.

[0052] Step S3 is the high temperature vibration performance test stage. After the low temperature vibration performance test is completed, the temperature needs to be quickly raised to a test temperature higher than room temperature. At this time, the input of liquid low temperature working fluid is stopped and the heating device 6 is turned on. The rotation of the axial flow fan 12 will quickly diffuse the heat of local heating, and the overall temperature will be increased. At the same time, normal temperature or high temperature and high pressure nitrogen or helium is introduced into the air inlet (the exhaust port 9 can be used directly) to quickly increase the temperature. After waiting for the high temperature to stabilize, the vibration test program is started.

[0053] S4. Change the low-temperature test temperature and the high-temperature test temperature in turn, and repeat the low-temperature vibration performance test at different low-temperature test temperatures and the high-temperature vibration performance test at different high-temperature test temperatures respectively. After the test is completed, take out the test piece, observe and record the appearance data of the test piece, and complete the vibration test.

[0054] Step S4 is to repeat the above steps S2 and S3 after changing the test temperature, and perform low-temperature vibration performance tests and high-temperature vibration performance tests at different test temperatures. After the set number of high and low temperature cycle tests, wait for the temperature to be controlled to room temperature, lift the cover plate 7 to take out the test piece, observe and record the appearance of the test piece after vibration, and complete the vibration test.

[0055] It is understandable that the mechanical refrigeration method in the traditional vibration test provides a small amount of cooling, a slow cooling rate, and is not suitable for working conditions with loaded vibration. The vibration test method of this embodiment uses low-temperature working fluid cooling and heating by a heating device to coordinate, uses an automatic control program (such as LabView) to control the low-temperature fluid flow valve to achieve regulation of the low-temperature working fluid flow, and controls the current of the heating rod to control the heating amount. The two control actions can make the internal temperature of the Dewar change according to the set heating and cooling rate, and remain stable at a specific temperature. Not only can it effectively perform vibration tests under extreme temperature conditions, but also improve the accuracy and reliability of the test through precise temperature control and a stable vibration structure. At the same time, compared with traditional mechanical refrigeration and cooling, this cooling method of this embodiment reduces the overall weight of the Dewar structure, which is conducive to loading and unloading and moving on the vibration table.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A Dewar structure, characterized in that: include: An outer cylinder (1), the outer bottom of the outer cylinder (1) being connected to an outer cylinder flange (2), and the outer cylinder flange (2) being used for connecting to a vibration table; An inner cylinder (3) is arranged in the outer cylinder (1); the top of the inner cylinder (3) is connected to the top of the outer cylinder (1); a vacuum cavity is formed between the outer wall of the inner cylinder (3) and the inner wall of the outer cylinder (1); a clamping assembly (4) is arranged in the inner cylinder (3); the clamping assembly (4) is used to clamp the test piece; a temperature sensor (5) and a heating device (6) are also arranged in the inner cylinder (3); A cover plate (7) is detachably connected to the outer tube (1) and the top of the inner tube (3); an infusion port (8) and an exhaust port (9) are provided on the cover plate (7).

2. The Dewar structure according to claim 1, characterized in that: A support column (10) is fixed to the inner bottom of the outer cylinder (1), the outer bottom of the inner cylinder (3) is connected to an inner cylinder flange (11), and the support column (10) is connected to the inner cylinder flange (11) so that the inner cylinder (3) is rigidly fixed relative to the outer cylinder (1).

3. The Dewar structure according to claim 1, characterized in that: A stirring mechanism is provided inside the inner cylinder (3), and the stirring mechanism is used to stir and accelerate heat exchange inside the inner cylinder (3).

4. The Dewar structure according to claim 3, characterized in that: The stirring mechanism comprises an axial flow fan (12), the axial flow fan (12) is connected to a driving shaft (13), the driving shaft (13) is rotatably mounted on a bearing seat (14), the bearing seat (14) is passed through the cover plate (7), a power motor (15) is arranged on the cover plate (7), an output shaft of the power motor (15) is connected to the driving shaft (13) via a coupling (16), and a motor protection cover (17) is arranged on the outer cover of the power motor (15).

5. The Dewar structure according to claim 1, characterized in that: The exhaust port (9) is a KF flange interface, and a solenoid valve is provided in the infusion port (8); a handle (18) and an aviation plug (19) are also symmetrically provided on the cover plate (7), and the aviation plug (19) is connected to the temperature sensor (5) and the heating device (6).

6. The Dewar structure according to claim 1, characterized in that: There are a plurality of temperature sensors (5), which are evenly mounted on the inner bottom, side walls and surface of the test piece of the inner cylinder (3); the heating device (6) comprises a plurality of heating rods, which are mounted on the inner bottom of the inner cylinder (3) and the surface of the test piece.

7. The Dewar structure according to any one of claims 1 to 6, characterized in that: The clamping assembly (4) comprises two clamping tables arranged opposite to each other, the clamping tables being fixed to the inner bottom of the inner cylinder (3), the two clamping tables being movably provided with clamping pieces, the clamping pieces on the two clamping tables corresponding to each other and arranged opposite to each other, so as to clamp the test piece through the clamping pieces arranged opposite to each other.

8. The Dewar structure according to claim 7, characterized in that: The clamping assembly (4) is made of Invar alloy.

9. A vibration test device, characterized in that: It comprises the dewar structure and a vibration table as claimed in any one of claims 1 to 8, wherein the dewar structure is connected and fixed to the vibration table via an outer cylinder flange (2).

10. A vibration test method, characterized in that: Applicable to the vibration test device of claim 9, the vibration test method comprising: The test piece is fixed to the clamping assembly (4) of the inner cylinder (3), the cover plate (7) is tightly closed, and the Dewar structure is connected and fixed to the vibration table through the outer cylinder flange (2); A low-temperature working fluid is sprayed into the inner tube (3) through an infusion port (8) on the cover plate (7) so that the low-temperature working fluid evaporates in the inner tube (3) to absorb heat and cool down, and an exhaust port (9) on the cover plate (7) is connected to an external gas collection system to collect the evaporated gaseous working fluid; the temperature of the test piece is monitored through a temperature sensor (5); when the temperature of the test piece reaches a low-temperature test temperature and the temperature is stable, the spraying rate of the low-temperature working fluid is adjusted so that the test piece maintains the low-temperature test temperature, the vibration table is started to perform a low-temperature vibration performance test, and the low-temperature vibration test parameters are recorded; After the low-temperature vibration performance test is completed, the spraying of the low-temperature working fluid is stopped, and the heating device (6) is used to heat the inner cylinder (3), and the temperature of the test piece is monitored by the temperature sensor (5). When the temperature of the test piece reaches the high-temperature test temperature, the heating power of the heating device (6) is adjusted to maintain the high-temperature test temperature of the test piece, and the vibration table is started to perform the high-temperature vibration performance test, and the high-temperature vibration test parameters are recorded; The low-temperature test temperature and the high-temperature test temperature are changed in turn, and the low-temperature vibration performance test at different low-temperature test temperatures and the high-temperature vibration performance test at different high-temperature test temperatures are repeated respectively. After the test is completed, the test piece is taken out, and the appearance data of the test piece is observed and recorded to complete the vibration test.

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