Device for measuring linear expansion coefficient and vacuum environment deformation of carbon fiber main bearing cylinder

Abstract

The utility model relates to the technical field of space camera main supporting structures, in particular to a carbon fiber main bearing cylinder linear expansion coefficient and vacuum environment deformation measuring device which comprises a vacuum tank and a deformation measuring device, and the deformation measuring device and a main bearing cylinder are assembled together and placed in the vacuum tank together. The deformation measuring device comprises a tool plate, a center measuring assembly, at least three edge measuring assemblies, a temperature sensor and a heating sheet. A to-be-measured carbon fiber main bearing cylinder is installed on the tool plate and covers the center measurement assembly and all the edge measurement assemblies. The linear expansion sensor and the measuring plate in the center measuring assembly and each edge measuring assembly are matched to complete the measurement of the relative displacement change of the linear expansion sensor and the carbon fiber main bearing cylinder when the temperature and vacuum environment of the carbon fiber main bearing cylinder are changed; the device which is lower in manufacturing cost and higher in measurement precision is provided for subsequent measurement of the linear expansion coefficient and the vacuum environment deformation of the carbon fiber main bearing cylinder.

Description

Technical Field

[0001] The utility model belongs to the technical field of main supporting structures of space cameras, and in particular relates to a device for measuring the linear expansion coefficient of a main carbon fiber bearing tube and deformation in a vacuum environment. Background Art

[0002] Most of the existing main bearing tube structures of space cameras are made of carbon fiber composite materials. However, since the carbon fiber structure is formed by manually bonding single-board prepregs according to the molding process and layer parameters, air bubbles will inevitably be mixed between the prepregs during the structural molding process to form structural cavities. After cooling, structural defects will be caused in the material, affecting the mechanical properties of the structure. Therefore, after the carbon fiber main bearing tube structure is formed, a thermal vacuum degassing test is required and the surface of the structure is artificially sealed. The purpose is to remove the easily vaporized organic small molecules and internal air bubbles in the material, eliminate structural defects and prevent air from entering the structure again, and improve the stability of the carbon fiber structure. However, since the artificial sealing treatment still needs to be carried out at room temperature and pressure, some air will still enter the carbon fiber main bearing tube structure during the thermal vacuum degassing test and the structural surface sealing treatment. At the same time, due to the different complexity of the structure, there will be omissions or defects in the artificial sealing treatment at small positions of the structure, resulting in air entering the carbon fiber structure again at room temperature and pressure, forming air bubbles and causing structural defects. Due to the above-mentioned deficiencies in the carbon fiber composite material molding process, and the fact that the main load-bearing cylinder structure is in a vacuum environment after being launched into space with the satellite, the air bubbles in the main load-bearing cylinder will be drawn out of the structure, causing unpredictable deformation of the structure.

[0003] Since the carbon fiber structure is formed by artificially bonding prepreg, it is easy to deviate from the theoretical molding process and the set layer parameters, resulting in a linear expansion coefficient that is different from the theoretical value. Moreover, most carbon fiber manufacturers currently do not provide the linear expansion coefficient measured after the structure is formed. At the same time, after the satellite is launched into space, it is affected by the instability of external heat flows such as solar radiation and the accuracy of thermal control. The main bearing tube structure is in an unstable temperature range environment. Therefore, the structure will deform due to temperature changes, resulting in changes in the distance between the primary and secondary mirrors, which affects the imaging quality of the entire machine. Therefore, it is necessary to measure the linear expansion coefficient of the main bearing tube.

[0004] Through the investigation, no common measuring device that can integrate linear expansion coefficient and vacuum environment deformation was found, and most linear expansion coefficient measuring devices are only for materials such as metal or glass, and no linear expansion coefficient measuring device for carbon fiber composite material structures was found. The main measurement methods are the top rod indirect method, telescope direct reading method and laser measurement method. The top rod indirect method and telescope direct reading method have low measurement accuracy. The laser measurement method requires the use of lasers and other equipment. While the measurement accuracy is high, the measurement cost is high. Utility Model Content

[0005] In view of this, the utility model aims to provide a device for measuring the linear expansion coefficient and vacuum environment deformation of a carbon fiber main bearing cylinder, which measures the linear expansion coefficient and vacuum environment structural deformation of the carbon fiber main bearing cylinder to be measured by a temperature sensor and a linear expansion sensor.

[0006] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0007] A device for measuring the linear expansion coefficient and deformation of a carbon fiber main bearing tube in a vacuum environment, comprising a vacuum tank and a deformation measuring device, wherein the deformation measuring device is placed in the vacuum tank;

[0008] The deformation measuring device includes a tooling plate, a center measuring component, no less than 3 edge measuring components, a temperature sensor and a heating plate; the carbon fiber main bearing cylinder is installed on the tooling plate through the mounting hole at the bottom thereof, and covers the center measuring component and all edge measuring components, and the assembly consisting of the carbon fiber main bearing cylinder and the deformation measuring device is placed in a vacuum tank;

[0009] The center measurement assembly and each edge measurement assembly include an adapter base, an indium steel support rod, a linear expansion sensor and a measurement plate; one end of the indium steel support rod is fixed to the tooling plate through the adapter base, and the linear expansion sensor is installed on the other end of the indium steel support rod through the sensor base; the measurement plate is installed on the top of the carbon fiber main bearing cylinder and is sensed by the linear expansion sensor, so that the linear expansion sensor completes the measurement of the relative position change with the measurement plate;

[0010] All edge measurement components are evenly distributed around the central measurement component. The heating plate is installed on the outer wall of the carbon fiber main bearing cylinder to complete the heating of the carbon fiber main bearing cylinder. The temperature sensor is installed on the carbon fiber main bearing cylinder and the indium steel support rod to complete the temperature measurement of the carbon fiber main bearing cylinder and the indium steel support rod.

[0011] Furthermore, the center measurement component is located at the center of the carbon fiber main bearing cylinder, and all edge measurement components are evenly distributed inside the carbon fiber main bearing cylinder.

[0012] Furthermore, at least one rotatable connecting nut is installed on both sides of the sensor base, and the linear expansion sensor is fixed to the sensor base through the rotatable connecting nut, so that the rotatable connecting nut can adjust the distance between the linear expansion sensor and the measuring plate.

[0013] Furthermore, the linear expansion sensor is an eddy current sensor, the body of which is fixed to the sensor base via a rotatable connecting nut; the probe of the eddy current sensor is inductively coupled to the measuring plate, so that the eddy current sensor measures the change in relative position of the probe and the measuring plate.

[0014] Furthermore, a smooth test plane is processed on one side of the measuring plate, and the distance between the probe and the test plane of the measuring plate is 1±0.4 mm.

[0015] Furthermore, a lifting ring for fixing a linear expansion coefficient and a vacuum environment deformation measuring device is provided on the edge of the tooling plate.

[0016] Compared with the prior art, the utility model can achieve the following beneficial effects:

[0017] (1) The device for measuring the linear expansion coefficient and vacuum environment deformation of the carbon fiber main bearing tube described in the utility model uses a temperature sensor and a linear expansion sensor to measure the temperature change and structural deformation of the carbon fiber main bearing tube under vacuum environment;

[0018] (2) The utility model is provided with a central measuring component and no less than three edge measuring components, which can obtain not only the axial deformation of the surface to be measured on the carbon fiber main bearing cylinder along the z direction, but also the tilt deformation of the surface to be measured around the x-axis and y-axis. The manufacturing cost of the entire measuring device is lower than that of other methods, and the measuring accuracy is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0020] Figure 1 It is a schematic diagram of the overall structure of the device for measuring the linear expansion coefficient and vacuum environment deformation of the main bearing tube of the carbon fiber according to the embodiment of the utility model;

[0021] Figure 2 It is a schematic diagram of the overall structure of the deformation measuring device according to an embodiment of the utility model;

[0022] Figure 3 It is a schematic cross-sectional structure diagram of the deformation measuring device according to an embodiment of the utility model;

[0023] Figure 4 It is a schematic diagram of the structure of the center measurement component or the edge measurement component described in an embodiment of the utility model.

[0024] Description of reference numerals:

[0025] 1. Vacuum tank; 2. Carbon fiber main bearing cylinder; 3. Experimental table; 4. Tooling plate; 5. Adapter base; 6. Indium steel support rod; 7. Linear expansion sensor; 8. Measuring plate; 9. Sensor base; 10. Lifting ring. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention of the utility model and do not constitute a limitation of the utility model.

[0027] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0028] In the description of the present utility model, it should be understood 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 present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0029] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" 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 it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0030] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0031] like Figure 1 As shown, the device for measuring the linear expansion coefficient and deformation of the carbon fiber main bearing cylinder in a vacuum environment described in the embodiment of the utility model includes a vacuum tank 1 and a deformation measuring device. The deformation measuring device is placed in the vacuum tank 1, and the vacuum tank 1 provides a vacuum environment for the carbon fiber main bearing cylinder 2 to be measured.

[0032] In order to ensure that the deformation measuring device and the carbon fiber main bearing cylinder 2 can be stably placed in the vacuum tank 1, the embodiment of the utility model preferably provides a test bench 3 for placing the deformation measuring device and the carbon fiber main bearing cylinder 2 in the vacuum tank 1.

[0033] like Figure 2 to Figure 4 As shown, the deformation measuring device includes a tooling plate 4, a center measuring component, no less than 3 edge measuring components, a temperature sensor and a heating plate. The carbon fiber main bearing cylinder 2 is installed on the tooling plate 4 through the mounting hole at its bottom, and covers the center measuring component and all edge measuring components, and the assembly consisting of the carbon fiber main bearing cylinder 2 and the deformation measuring device is placed in the vacuum tank 1.

[0034] The center measurement assembly and each edge measurement assembly include an adapter base 5, an indium steel support rod 6, a linear expansion sensor 7 and a measuring plate 8. One end of the indium steel support rod 6 is fixed to the tooling plate 4 through the adapter base 5, and the linear expansion sensor 7 is installed on the other end of the indium steel support rod 6 through the sensor base 9. The measuring plate 8 is installed on the top of the carbon fiber main bearing cylinder 2, and the linear expansion sensor 7 is sensed by the linear expansion sensor 7 by adjusting the distance between the linear expansion sensor 7 and the linear expansion sensor 7, so that the linear expansion sensor 7 can complete the measurement of the change in the relative position with the measuring plate 8.

[0035] All edge measurement components are evenly distributed around the central measurement component, and the heating plate is installed on the outer wall of the carbon fiber main bearing cylinder 2 to complete the heating of the carbon fiber main bearing cylinder 2. The temperature sensor is installed on the carbon fiber main bearing cylinder 2 and the indium steel support rod 6 to complete the temperature measurement of the carbon fiber main bearing cylinder 2 and the indium steel support rod 6.

[0036] In the embodiment of the present invention, the temperature sensor model is MF501, which is mainly used to determine the real-time temperature of the carbon fiber main bearing cylinder 2 and the indium steel support rod 6 during the test. The measurement error of the device can be reduced by calculation. A certain number of temperature sensors can be evenly distributed on the outer wall of the carbon fiber main bearing cylinder 2 and the indium steel support rod 6 according to the actual test situation, and the accurate temperature of both can be fully measured. The utility model does not make specific requirements on the actual application quantity and installation position of the temperature sensor. The heating plate is processed and customized, with multiple size models, and is installed on the outer wall of the carbon fiber main bearing cylinder 2. Its purpose is to heat the carbon fiber main bearing cylinder 2 when the temperature in the vacuum tank 1 is relatively low, increase the thermal deformation of the carbon fiber main bearing cylinder 2, and improve the measurement accuracy. The utility model does not make specific requirements on the heating plate model and the detailed installation position.

[0037] In the embodiment of the utility model, in order to fully reflect the deformation of the carbon fiber main bearing cylinder 2, the central measuring component is located at the center of the carbon fiber main bearing cylinder 2, and the number of edge measuring components is preferably set to 3 and evenly distributed inside the carbon fiber main bearing cylinder 2. The central measuring component can directly reflect the deformation of the carbon fiber main bearing cylinder 2, and the three edge measuring components verify whether there is rotation around the x-axis and y-axis on the upper surface of the carbon fiber main bearing cylinder 2. If the deformation of the central measuring component and the edge measuring component is the same, it indicates that the carbon fiber main bearing cylinder 2 has no tilt deformation, that is, only translational deformation along the z-axis direction occurs, which can verify the consistency of the linear expansion coefficient of the carbon fiber main bearing cylinder 2 and the deformation in the vacuum environment.

[0038] Specifically, in the embodiment of the utility model, the indium steel support rod 6 and the adapter base 5 are connected together by six M5x12 screws on the surface and bottom between the two, which can ensure the coaxiality between the two and the connection strength. The sensor base 9 is fixed to the indium steel support rod 6 by four M3x10 screws, and the adapter base 5 is installed on the tooling plate 4 by 24 M5x12 screws. After adjusting the position of the carbon fiber main bearing cylinder 2, 30 M5x16 screws are used to fix the edge of the tube mouth of the carbon fiber main bearing cylinder 2 on the tooling plate 4, and the measuring plate 8 is installed on the top of the carbon fiber main bearing cylinder 2 by six M3x8 screws.

[0039] The linear expansion sensor 7 preferably adopts DH5922D+eddy current sensor 5E101. The main body of the eddy current sensor is an M6 threaded column installed on the sensor base 9 through a rotatable connecting nut. The diameter of the probe of the eddy current sensor is 6.5mm and the length is 5mm. The eddy current sensor adjusts the distance between the probe of the eddy current sensor and a smooth test plane on one side of the measuring plate 8 through a rotatable connecting nut to maintain at 1±0.4mm, so that the eddy current sensor can sense the measuring plate 8 and complete the measurement of the change in the relative position of the eddy current sensor and the measuring plate 8.

[0040] When measuring the linear expansion coefficient of the carbon fiber main bearing cylinder 2, the carbon fiber main bearing cylinder 2 is installed on the deformation measuring device, and the carbon fiber main bearing cylinder 2 and the deformation measuring device are placed in the vacuum tank 1. The vacuum tank 1 is closed and left for a certain period of time until the temperature in the tank stabilizes, and the readings of the temperature sensors on the carbon fiber main bearing cylinder 2 and the indium steel support rod 6, as well as the readings of the linear expansion sensor 7 are recorded.

[0041] The heating plate is controlled to heat the carbon fiber main bearing cylinder 2 to different temperatures for N times. After heating for a certain time to a certain temperature, the readings of the temperature sensors on the carbon fiber main bearing cylinder 2 and the indium steel support rod 6 and the readings of the linear expansion sensor 7 are recorded, and the linear expansion coefficient of the carbon fiber main bearing cylinder 2 at different temperatures is obtained by the following formula:

[0042]

[0043] Where i = {1, 2, 3, ..., N} represents the number of heating times, α T-i represents the linear expansion coefficient of the carbon fiber main bearing cylinder 2 during the i-th heating, H R0 Indicates the reading of the linear expansion sensor 7 when not heated, H Ri represents the reading of the linear expansion sensor 7 during the i-th heating; T RG-0 It represents the reading of the temperature sensor on the indium steel support rod 6 when it is not heated, T RG-i represents the reading of the temperature sensor on the indium steel support rod 6 during the i-th heating, L G represents the length of the indium steel support rod 6, α G represents the thermal expansion coefficient of the indium steel support rod 6; T RT-0 Indicates the reading of the temperature sensor on the carbon fiber main bearing cylinder 2 when not heated, T RT-i represents the reading of the temperature sensor on the carbon fiber main bearing cylinder 2 during the i-th heating, L T Indicates the length of the carbon fiber main bearing cylinder 2.

[0044] Then the average linear expansion coefficient of the carbon fiber main bearing cylinder 2 is obtained:

[0045]

[0046] Among them, α T Indicates the average linear expansion coefficient of the carbon fiber main bearing cylinder 2. According to the above content, the average linear expansion coefficient reflected by the central measurement component and the average linear expansion coefficient reflected by each edge measurement component are calculated. By comparing the values, the consistency of the linear expansion coefficient of the carbon fiber main bearing cylinder 2 can be obtained. If the values ​​are the same, it proves that the linear expansion coefficient of the entire carbon fiber main bearing cylinder 2 has good consistency.

[0047] When measuring the deformation of the carbon fiber main bearing cylinder 2 in a vacuum environment, the carbon fiber main bearing cylinder 2 is installed on the deformation measuring device, and the carbon fiber main bearing cylinder 2 and the deformation measuring device are placed in the vacuum tank 1. The vacuum tank 1 is closed and left for a certain period of time until the temperature in the tank stabilizes, and the readings of the temperature sensors on the carbon fiber main bearing cylinder 2 and the indium steel support rod 6, as well as the readings of the linear expansion sensor 7 are recorded.

[0048] The vacuum tank 1 is evacuated to a vacuum state and maintained for a period of time until a stable state is reached. The readings of the temperature sensors on the carbon fiber main bearing cylinder 2 and the indium steel support rod 6 and the readings of the linear expansion sensor 7 are recorded M times at a certain interval, and the linear expansion coefficient of the carbon fiber main bearing cylinder 2 under different measurement times is obtained by the following formula:

[0049] Δ Z-j =H Zj -HZ0 -((T ZG-j -T ZG-0 )×L G ×α G

[0050] -(T ZT-j -T ZT-0 )×L T ×α T )

[0051] Where j = {1, 2, 3, ..., M} represents the number of measurements, Δ Z-j represents the vacuum environment deformation of the carbon fiber main bearing cylinder 2 during the jth measurement, H Z0 Indicates the reading of the linear expansion sensor 7 when no vacuum is drawn, H Zj represents the reading of the linear expansion sensor 7 at the jth measurement after vacuuming; T ZG-0 It indicates the reading of the temperature sensor on the indium steel support rod 6 when no vacuum is drawn, T ZG-i It represents the reading of the temperature sensor on the indium steel support rod 6 at the jth measurement after vacuuming, L G represents the length of the indium steel support rod 6, α G represents the thermal expansion coefficient of the indium steel support rod 6; T ZT-0 Indicates the reading of the temperature sensor on the carbon fiber main bearing cylinder 2 when no vacuum is drawn, T ZT-i It indicates the reading of the temperature sensor on the carbon fiber main bearing cylinder 2 at the jth measurement after vacuuming, L T Indicates the length of the carbon fiber main bearing cylinder 2.

[0052] Then the average vacuum environment deformation of the carbon fiber main bearing cylinder 2 is obtained:

[0053]

[0054] Among them, Δ Z It indicates the average vacuum environment deformation of the carbon fiber main bearing cylinder 2. By calculating the average vacuum environment deformation reflected by the center measurement component and the average vacuum environment deformation reflected by each edge measurement component according to the above content, the uniformity of the deformation of the carbon fiber main bearing cylinder 2 in the vacuum environment can be obtained. Combining the above indicators, a more comprehensive evaluation of the product quality of the carbon fiber main bearing cylinder can be made.

[0055] In order to make the deformation measuring device fully adaptable to various working environments, in the embodiment of the utility model, a lifting ring 10 for fixing the tooling plate is preferably provided on the edge of the tooling plate 4. When the deformation measuring device provided by the utility model needs to be used in the air, a steel wire rope can be used to tie it to the lifting ring 10 to suspend the deformation measuring device in the working environment.

[0056] The above specific implementations do not constitute a limitation on the protection scope of the present utility model. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present utility model shall be included in the protection scope of the present utility model.

Claims

1. A device for measuring the linear expansion coefficient and vacuum environment deformation of a carbon fiber main bearing tube, characterized in that: It includes a vacuum tank and a deformation measuring device used when measuring the carbon fiber main bearing cylinder, and the deformation measuring device is placed in the vacuum tank; wherein, The deformation measuring device comprises a tooling plate, a center measuring component, no less than 3 edge measuring components, a temperature sensor and a heating plate; the carbon fiber main bearing cylinder is installed on the tooling plate through the mounting hole at the bottom thereof, and covers the center measuring component and all edge measuring components, and the assembly consisting of the carbon fiber main bearing cylinder and the deformation measuring device is placed in the vacuum tank; The center measurement assembly and each edge measurement assembly include an adapter base, an indium steel support rod, a linear expansion sensor and a measurement plate; one end of the indium steel support rod is fixed to the tooling plate through the adapter base, and the linear expansion sensor is installed on the other end of the indium steel support rod through the sensor base; the measurement plate is installed on the top of the carbon fiber main bearing cylinder and is sensed by the linear expansion sensor, so that the linear expansion sensor completes the measurement of the relative position change with the measurement plate; All edge measurement components are evenly distributed around the central measurement component. The heating plate is installed on the outer wall of the carbon fiber main bearing cylinder to complete the heating of the carbon fiber main bearing cylinder; the temperature sensor is installed on the carbon fiber main bearing cylinder and the indium steel support rod to complete the temperature measurement of the carbon fiber main bearing cylinder and the indium steel support rod.

2. The device for measuring the linear expansion coefficient and vacuum environment deformation of the carbon fiber main bearing cylinder according to claim 1, characterized in that: The center measurement component is located at the center of the carbon fiber main bearing cylinder, and all edge measurement components are evenly distributed inside the carbon fiber main bearing cylinder.

3. The device for measuring the linear expansion coefficient and vacuum environment deformation of the carbon fiber main bearing cylinder according to claim 1, characterized in that: At least one rotatable connecting nut is installed on both sides of the sensor base, and the linear expansion sensor is fixed to the sensor base through the rotatable connecting nut, so that the rotatable connecting nut can adjust the distance between the linear expansion sensor and the measuring plate.

4. The device for measuring the linear expansion coefficient and vacuum environment deformation of the carbon fiber main bearing cylinder according to claim 3 is characterized in that: The linear expansion sensor is an eddy current sensor, and the main body of the eddy current sensor is fixed to the sensor base through the rotatable connecting nut; the probe of the eddy current sensor is sensed by the measuring plate, so that the eddy current sensor can complete the measurement of the change in the relative position of the probe and the measuring plate.

5. The device for measuring the linear expansion coefficient and vacuum environment deformation of the carbon fiber main bearing cylinder according to claim 4, characterized in that: One side of the measuring plate is processed with a smooth testing plane, and the distance between the probe and the testing plane of the measuring plate is 1±0.4 mm.

6. The device for measuring the linear expansion coefficient and vacuum environment deformation of the carbon fiber main bearing cylinder according to claim 1, characterized in that: A lifting ring for fixing the linear expansion coefficient and vacuum environment deformation measuring device is provided on the edge of the tooling plate.

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