Method for evaluating service life of solid lubricating film of spacecraft mechanism based on humidity accumulation

Abstract

The invention discloses a spacecraft mechanism solid lubricating film life evaluation method based on humidity accumulation, which finely considers the accumulation effect of storage humidity on storage life, and considers multiple parameters such as lubricating film function, in-orbit use, ground test, safety coefficient and the like at the same time. The problem that the current spacecraft solid lubricating film service life evaluation is lack of a refined method is solved, and the method has high economic benefits.

Description

Technical Field

[0001] The invention relates to a method for evaluating the life of a solid lubricating film of a spacecraft mechanism based on humidity accumulation, and belongs to the technical field of spacecraft mechanisms. Background Art

[0002] Spacecraft mechanisms generally use lubrication technology in the moving parts, the purpose of which is to reduce the friction of the moving parts or prevent the occurrence of cold welding. Generally speaking, molybdenum disulfide solid lubrication film is often used for low-speed, intermittent motion and mechanisms directly exposed to space.

[0003] During the storage process of the solid lubricating film on the ground, the solid lubricating film reacts chemically with water molecules in the air to generate new substances, thus affecting its life. If the solid lubricating film is stored for too long or the storage humidity is too high, it may cause the lubricating film to fail, which in turn causes wear of the kinematic pair and increased rotational friction. In the worst case, it will increase the movement resistance of the mechanism or even cause it to get stuck, threatening the safety of the entire spacecraft. Therefore, it is very important to evaluate the life of the solid lubricating film of the spacecraft mechanism.

[0004] At present, the storage life of solid lubricant films in spacecraft mechanisms is usually defined in a relatively broad way. For example, a certain unit defines the life of molybdenum disulfide lubricant films as follows:

[0005] 1) The relative humidity of the environment is always controlled within 33% and the storage period is 10 years.

[0006] 2) Storage under the condition of relative humidity of 33% to 60%:

[0007] a) If the base metal does not rust, the storage period is 5 years;

[0008] b) In other cases, the storage period is 3 years.

[0009] The current evaluation methods have the following main problems:

[0010] a) The current method only makes broad provisions and only meets the minimum envelope of the life of lubricating products. For example, the storage life at 0-33% humidity is 10 years. In fact, the humidity range from 0 to 33% is a very large span. Theoretically, the molybdenum disulfide film layer can remain stable for a long time in an environment with 0 humidity, and its storage life is much greater than 10 years, which can be defined as long-term; and the storage life is only 10 years in an environment with 33% humidity.

[0011] b) The current method does not consider the differences in the on-orbit service life requirements of different types of mechanisms. In fact, the on-orbit usage patterns of spacecraft mechanisms vary greatly. Some mechanisms need to operate for a long time, such as the SADA mechanism of the solar wing, while others only need to move once, such as the locking mechanism of the solar wing. This requires that the required on-orbit service life for different mechanisms needs to be considered when evaluating the ground storage life.

[0012] c) The current method does not distinguish between solid lubricating products based on their main functions when evaluating their lifespan. The main functions of solid lubricating films are to reduce friction and prevent cold welding. Cold welding requires a clean, uncontaminated metal contact surface to allow atomic bonds to form welds. Failure of the solid lubricating film layer will not cause cold welding of the mechanism. Therefore, for lubricating films that only prevent cold welding, their lifespan is long. Only for solid lubricating films with lubrication functions, the impact of the storage environment needs to be considered.

[0013] Therefore, in the ground storage of spacecraft structures, it is necessary to develop a scientific and refined life assessment method, which has high economic value and practical significance. Summary of the invention

[0014] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art and to provide a method for evaluating the life of a solid lubricating film of a spacecraft mechanism based on humidity accumulation, which can provide a refined method for evaluating the remaining life of a solid lubricating film stored on the ground.

[0015] The technical solution of the present invention is:

[0016] The present invention discloses a method for evaluating the life of a solid lubricating film of a spacecraft mechanism based on humidity accumulation, comprising:

[0017] According to the product design, the functions of the solid lubricating film of the spacecraft mechanism are classified and the classification results are obtained;

[0018] According to the classification results, it is determined whether the function of the solid lubricating film is to prevent cold welding. If so, the life assessment result is long-term; otherwise, tribological tests are carried out on the sample specimens of the solid lubricating film of the spacecraft mechanism to obtain the tribological life of the lubricating layer;

[0019] Carry out natural storage test or accelerated aging test on the specimens of solid lubricating film of spacecraft mechanism to obtain the storage life and humidity at different time;

[0020] Calculate the cumulative value of the life humidity of the lubricating film based on the storage life and humidity at different times;

[0021] Obtain the history of the solid lubricating film sample of the spacecraft mechanism since the day it was unsealed, and obtain the humidity data S at different times during the whole process;

[0022] Based on the humidity data, calculate the cumulative humidity value of the solid lubricating film sample of the spacecraft mechanism from the date of opening to the present;

[0023] Obtain the parameters of the solid lubricant film of the spacecraft mechanism according to product design, ground test requirements and actual on-orbit work requirements;

[0024] The remaining life of the solid lubricating film for the spacecraft mechanism is calculated based on the tribological life of the lubricating layer, the accumulated humidity value of the authentic sample of the solid lubricating film for the spacecraft mechanism from the date of opening to the present, and the parameters of the solid lubricating film for the spacecraft mechanism.

[0025] Furthermore, in the above method, the classification results include: lubrication function, cold welding prevention function and both lubrication and cold welding prevention functions.

[0026] Furthermore, in the above method, the life humidity cumulative value of the lubricating film is specifically:

[0027]

[0028] in, is the life humidity accumulation value of the lubricating film, T 寿命 is the storage life, and SP is the humidity at different times.

[0029] Furthermore, in the above method, the cumulative humidity value of the solid lubricating film sample product of the spacecraft mechanism from the date of unsealing to the present is specifically:

[0030]

[0031] in, is the accumulated humidity value of the solid lubricating film sample of the spacecraft mechanism from the date of unsealing to the present, S is the humidity data at different times in the whole process, and t is the time.

[0032] Furthermore, in the above method, the solid lubricating film parameters of the spacecraft mechanism include the number of ground motion circles N 地 , Number of on-orbit movements N 天 , Ground life test duration factor Z 地 , Ground life test duration factor Z 天 , subsequent storage average humidity S 后 .

[0033] Furthermore, in the above method, the remaining life of the solid lubricating film of the spacecraft mechanism is specifically:

[0034]

[0035] in, This is the cumulative humidity value of the solid lubricating film sample of the spacecraft mechanism from the date of opening to the present. is the life humidity accumulation value of the lubricating film, and N is the tribological life of the lubricating layer.

[0036] The beneficial effects of the present invention and the prior art are:

[0037] (1) The current definition of the life of the lubricating film of the spacecraft mechanism does not distinguish between functions. The present invention uses mechanism analysis to distinguish the life of the anti-cold welding function and the lubrication function, thereby extending the life of the mechanism components that are only used for the anti-cold welding function to a long term, thereby avoiding the early scrapping of the mechanism components that are only used for the anti-cold welding function due to storage date issues.

[0038] (2) The current evaluation of the ground storage life of solid lubricating films of spacecraft mechanisms only defines the envelope properties, without considering the cumulative effect of storage humidity in detail, nor considering important parameters such as the actual on-orbit use requirements of the mechanism and the number of ground tests. The present invention provides a method for evaluating the remaining ground storage life of solid lubricating films of spacecraft mechanisms based on humidity accumulation, which is a relatively accurate method for evaluating the ground storage life. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0040] The present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0041] like Figure 1 As shown, the present invention discloses a method for evaluating the life of a solid lubricating film of a spacecraft mechanism based on humidity accumulation, comprising:

[0042] According to the product design, the functions of the solid lubricating film of the spacecraft mechanism are classified and the classification results are obtained;

[0043] According to the classification results, it is determined whether the function of the solid lubricating film is to prevent cold welding. If so, the life assessment result is long-term; otherwise, tribological tests are carried out on the sample specimens of the solid lubricating film of the spacecraft mechanism to obtain the tribological life of the lubricating layer;

[0044] Carry out natural storage test or accelerated aging test on the specimens of solid lubricating film of spacecraft mechanism to obtain the storage life and humidity at different time;

[0045] Calculate the cumulative value of the life humidity of the lubricating film based on the storage life and humidity at different times;

[0046] Obtain the history of the solid lubricating film sample of the spacecraft mechanism since the day it was unsealed, and obtain the humidity data at different times during the whole process;

[0047] Based on the humidity data, calculate the cumulative humidity value of the solid lubricating film sample of the spacecraft mechanism from the date of opening to the present;

[0048] Obtain the parameters of the solid lubricant film of the spacecraft mechanism according to product design, ground test requirements and actual on-orbit work requirements;

[0049] The remaining life of the solid lubricating film for the spacecraft mechanism is calculated based on the tribological life of the lubricating layer, the accumulated humidity value of the authentic sample of the solid lubricating film for the spacecraft mechanism from the date of opening to the present, and the parameters of the solid lubricating film for the spacecraft mechanism.

[0050] Preferably, the classification results include: lubrication function, cold welding prevention function and both lubrication and cold welding prevention functions.

[0051] Preferably, the life humidity accumulation value of the lubricating film is specifically:

[0052]

[0053] in, is the life humidity accumulation value of the lubricating film, T 寿命 is the storage life, and SP is the humidity at different times.

[0054] Preferably, the cumulative humidity value of the solid lubricating film sample of the spacecraft mechanism from the date of unsealing to the present is:

[0055]

[0056] in, is the accumulated humidity value of the solid lubricating film sample of the spacecraft mechanism from the date of unsealing to the present, S is the humidity data at different times in the whole process, and t is the time.

[0057] Preferably, the solid lubricant film parameters of the spacecraft mechanism include the number of ground motion circles N 地 , Number of on-orbit movements N 天 , Ground life test duration factor Z 地 , Ground life test duration factor Z 天 , subsequent storage average humidity S 后 .

[0058] Preferably, the remaining life of the solid lubricating film of the spacecraft mechanism is specifically:

[0059]

[0060] in, This is the cumulative humidity value of the solid lubricating film sample of the spacecraft mechanism from the date of opening to the present. is the life humidity accumulation value of the lubricating film, and N is the tribological life of the lubricating layer.

[0061] Example

[0062] The present invention provides a method for assessing the remaining life of a solid lubricating film of a spacecraft mechanism on the ground based on humidity accumulation, and describes the method by taking the assessment of the remaining life of a solid lubricating film of a certain model and mechanism on the ground as an example.

[0063] In order to achieve the above object, the present invention adopts the following technical scheme:

[0064] a) According to the design of a certain mechanism of the spacecraft, the function of the solid lubricating film of the joint is defined, and its function has both lubrication function and cold welding prevention function, and then proceeds to step b);

[0065] b) Tribological tests were conducted on a sample of the lubricating film of a spacecraft mechanism, and the tribological life of the lubricating layer was obtained to be 4*10 5 lock up;

[0066] c) Carry out natural storage test on the sample of lubricating film of a certain structure product of spacecraft to obtain the storage life T 寿命 = 10 years, obtain the humidity SP at different times: 23% humidity for 5 years, 43% humidity for 5 years, and calculate the cumulative value of the life humidity of the lubricating film:

[0067]

[0068] d) Sort out the history of the lubricating film sample of a certain structure of the spacecraft since the day it was unsealed, and obtain the humidity data S at different times during the whole process: 50% humidity for 1 year, 30% humidity for 1 year;

[0069] e) Calculate the cumulative humidity value of the product from the date of opening to the present;

[0070]

[0071] f) According to product design, ground test requirements and actual on-orbit work requirements, obtain the number of ground movement circles N of the lubricating film of the mechanism product 地 =3*10 4 , Number of on-orbit movements N 天 =1*10 4 , Ground life test duration factor Z 地 =4, on-orbit life test duration factor Z 天 =10, subsequent storage average humidity S 后 =25%;

[0072] g) Calculate the remaining life of the lubricating film of a certain mechanism product;

[0073]

[0074] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0075] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

[0076] The contents not described in detail in the specification of the present invention belong to the common knowledge of the professionals in this field.

Claims

1. A method for evaluating the life of a solid lubricating film of a spacecraft mechanism based on humidity accumulation, characterized in that: include: According to the product design, the functions of the solid lubricating film of the spacecraft mechanism are classified and the classification results are obtained; According to the classification results, it is determined whether the function of the solid lubricating film is to prevent cold welding. If so, the life assessment result is long-term; otherwise, tribological tests are carried out on the sample specimens of the solid lubricating film of the spacecraft mechanism to obtain the tribological life of the lubricating layer; Carry out natural storage test or accelerated aging test on the sample of solid lubricating film of spacecraft mechanism to obtain the storage life and humidity at different time; Calculate the cumulative value of the life humidity of the lubricating film based on the storage life and humidity at different times; Obtain the history of the solid lubricating film sample of the spacecraft mechanism since the day it was unsealed, and obtain the humidity data at different times during the whole process; Based on the humidity data, calculate the cumulative humidity value of the solid lubricating film sample of the spacecraft mechanism from the date of opening to the present; Obtain the parameters of the solid lubricant film of the spacecraft mechanism according to product design, ground test requirements and actual on-orbit work requirements; The remaining life of the solid lubricating film for the spacecraft mechanism is calculated based on the tribological life of the lubricating layer, the accumulated humidity value of the authentic sample of the solid lubricating film for the spacecraft mechanism from the date of opening to the present, and the parameters of the solid lubricating film for the spacecraft mechanism.

2. The method for evaluating the life of a solid lubricating film of a spacecraft mechanism based on humidity accumulation according to claim 1, characterized in that: The classification results include: lubrication function, cold welding prevention function and both lubrication and cold welding prevention functions.

3. The method for evaluating the life of a solid lubricating film of a spacecraft mechanism based on humidity accumulation according to claim 1, characterized in that: The life humidity accumulation value of the lubricating film is specifically: in, is the life humidity accumulation value of the lubricating film, T 寿命 is the storage life, and SP is the humidity at different times.

4. The method for evaluating the life of a solid lubricating film of a spacecraft mechanism based on humidity accumulation according to claim 1, characterized in that: The cumulative humidity value of the solid lubricating film sample of the spacecraft mechanism from the date of opening to the present is: in, is the accumulated humidity value of the solid lubricating film sample of the spacecraft mechanism from the date of unsealing to the present, S is the humidity data at different times in the whole process, and t is the time.

5. The method for evaluating the life of a solid lubricating film of a spacecraft mechanism based on humidity accumulation according to claim 1, characterized in that: The solid lubricant film parameters of the spacecraft mechanism include the number of ground motion circles N 地 , Number of on-orbit movements N 天 , Ground life test duration factor Z 地 , Ground life test duration factor Z 天 and subsequent storage average humidity S 后 .

6. The method for evaluating the life of a solid lubricating film of a spacecraft mechanism based on humidity accumulation according to claim 5, characterized in that: The remaining life of the solid lubricant film of the spacecraft mechanism is: in, This is the cumulative humidity value of the solid lubricating film sample of the spacecraft mechanism from the date of opening to the present. is the life humidity accumulation value of the lubricating film, and N is the tribological life of the lubricating layer.

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