CN111220054B - Dead gap test method and test tool for infrared detector Dewar refrigeration assembly - Google Patents
Dead gap test method and test tool for infrared detector Dewar refrigeration assembly Download PDFInfo
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- CN111220054B CN111220054B CN202010031931.3A CN202010031931A CN111220054B CN 111220054 B CN111220054 B CN 111220054B CN 202010031931 A CN202010031931 A CN 202010031931A CN 111220054 B CN111220054 B CN 111220054B
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- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
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Abstract
The invention discloses a dead gap test method and a test tool for an infrared detector Dewar refrigeration assembly, wherein the infrared detector Dewar refrigeration assembly comprises a Dewar assembly and a refrigerator which are detachably connected, a pushing piston assembly of the refrigerator is suitable for reciprocating motion in a cold finger of the Dewar assembly, and a coupling surface of the Dewar assembly is in contact with a coupling surface of the refrigerator; the method comprises the following steps: testing the distance H1 between the coupling surface of the dewar assembly and the inner bottom wall of the cold finger; driving the end face of the free end of the pushing piston assembly to move to the top dead center position, and testing the distance H2 between the end face of the free end of the pushing piston assembly and the coupling surface of the refrigerator; and calculating the dead space H1-H2 of the infrared detector Dewar refrigeration assembly according to H1 and H2. By adopting the method and the device, the test of the dead gap of the pushing piston assembly of the infrared detector can be realized, the measurement method is simple in design and strong in operability, and the interference problem which possibly occurs when the Stirling refrigerator is coupled with the Dewar assembly can be effectively avoided.
Description
Technical Field
The invention relates to the technical field of infrared detectors, in particular to a dead clearance test method and a test tool for a Dewar refrigeration assembly of an infrared detector.
Background
The refrigerator structurally generally adopts a direct current brushless motor to drive a crankshaft connecting rod mechanism to reciprocate so as to realize reverse refrigeration cycle to finish refrigeration. In practical applications, it is necessary to couple the refrigerator and the infrared detector dewar assembly (DDA assembly) together to form a complete infrared detector dewar refrigeration assembly (IDDCA assembly). When the IDDCA assembly works, the pushing piston assembly moves back and forth in the cold finger of the refrigerating machine. For the integrated dewar structure, the dewar cold finger is also a refrigerator cold finger, if the dewar structure is not matched with the refrigerator in size, the refrigerator pushing piston assembly is likely to interfere with the dewar cold finger to cause impact, and further the infrared detector assembly is caused to fail. Therefore, when the refrigerator is coupled with the dewar assembly of the infrared detector, the minimum clearance between the refrigerator pushing piston assembly and the bottom of the dewar cold finger needs to be tested, namely the distance from the top end of the pushing piston assembly to the bottom of the dewar cold finger is pushed when the refrigerator pushing piston assembly moves to the top dead center. The sliding piston assembly belongs to a moving part and has no radial constraint, so that the sliding piston assembly is difficult to measure. It is very important to establish an effective refrigerator dead-gap test method.
Disclosure of Invention
The embodiment of the invention provides a dead clearance test method and a test tool for an infrared detector Dewar refrigeration assembly, which are used for solving the problem that the dead clearance test of a pushing piston assembly in the prior art is difficult.
The embodiment of the invention provides a dead gap test method of an infrared detector Dewar refrigeration assembly, wherein the infrared detector Dewar refrigeration assembly comprises a Dewar assembly and a refrigerator which are detachably connected, a pushing piston assembly of the refrigerator is suitable for reciprocating motion in a cold finger of the Dewar assembly, and a coupling surface of the Dewar assembly is in contact with a coupling surface of the refrigerator;
the method comprises the following steps:
testing the distance H1 between the coupling surface of the dewar assembly and the inner bottom wall of the cold finger;
driving the end face of the free end of the pushing piston assembly to move to a top dead center position, and testing the distance H2 between the end face of the free end of the pushing piston assembly and the coupling surface of the refrigerator;
and calculating the dead space H1-H2 of the infrared detector Dewar refrigeration assembly according to the H1 and the H2.
According to some embodiments of the invention, the testing a distance H1 between the coupling face of the dewar assembly and the inner bottom wall of the cold finger comprises:
measuring the distance Ha between the end surface of the Dewar assembly close to one end of the pushing piston assembly and the inner bottom wall of the cold finger;
measuring a distance Hb between an end surface of the Dewar assembly close to one end of the pushing piston assembly and a coupling surface of the Dewar assembly;
calculating the distance H1 between the coupling surface of the Dewar assembly and the inner bottom wall of the cold finger according to the Ha and the Hb.
According to some embodiments of the invention, said driving the end face of the free end of the moving piston assembly to the top dead centre position, testing the distance H2 between the end face of the free end of the moving piston assembly and the coupling face of the refrigerator comprises:
assembling the dial indicator to one end of the sleeve to form a pushing piston assembly height gauge;
fitting the pushed piston assembly height gauge to a standard height gauge, adjusting the dial gauge pointer initial position based on the standard height gauge;
fitting the pushing piston assembly height gauge to the pushing piston assembly;
dismantling a stator assembly of the refrigerator, placing a magnetic piece on a rotor protective sleeve of the refrigerator and rotating along the periphery of the rotor protective sleeve so as to drive the pushing piston assembly to move;
when the end face of the free end of the pushing piston assembly moves to the top dead center position, recording the reading of the dial indicator;
and determining the distance H2 between the end surface of the free end of the pushing piston assembly and the coupling surface of the refrigerator according to the reading of the dial indicator.
In some embodiments of the invention, the method further comprises:
preparing a standard height gauge according to the H1 before assembling the pushed piston assembly height gauge to the standard height gauge, adjusting the initial position of the pointer of the dial gauge based on the standard height gauge.
In some embodiments of the invention, said fitting said pushed piston assembly height gauge to a standard height gauge, adjusting an initial position of a pointer of said dial gauge based on said standard height gauge, comprises:
sleeving the sleeve on the standard height gauge in a sleeved mode, and enabling the end face of the other end of the sleeve to be flush with the zero scale of the standard height gauge;
recording the reading of a small dial of the dial indicator;
and zeroing the reading of the large dial of the dial indicator.
In some embodiments of the invention, said fitting said pushing piston assembly height gauge to said pushing piston assembly comprises:
and sleeving the sleeve on the pushing piston assembly in a sleeving manner, and enabling the end face of the other end of the sleeve to be in contact with the coupling surface of the refrigerator.
In some embodiments of the invention, the magnetic member is a magnet.
In some embodiments of the invention, said recording the reading of said dial indicator when the end face of the free end of said pusher piston assembly moves to the top dead centre position comprises:
observing the reading of the dial indicator during the movement of the pushing piston assembly;
and when the reading of the dial indicator reaches the maximum value, recording the reading of the dial indicator.
According to some embodiments of the invention the cryocooler is a rotary integrated stirling cryocooler.
The embodiment of the invention also provides a dead gap test tool for the infrared detector Dewar refrigeration assembly, which comprises the following components:
a standard height gauge;
the pushing piston assembly height gauge comprises a dial indicator and a sleeve, wherein the dial indicator is arranged at one end of the sleeve, and the pushing piston assembly height gauge can be assembled to the standard height gauge so as to adjust the initial position of a pointer of the dial indicator.
By adopting the embodiment of the invention, the dead clearance of the pushing piston assembly of the infrared detector Dewar refrigeration assembly can be tested, the measuring method has simple design and strong operability, the interference problem possibly occurring when the refrigerator is coupled with the infrared detector Dewar assembly can be effectively avoided, and the application level of the IDDCA assembly of the infrared detector Dewar refrigeration assembly is improved.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
FIG. 1 is a flow chart of a method for testing a dead gap of a Dewar refrigeration assembly of an infrared detector in an embodiment of the invention;
FIG. 2 is a schematic structural diagram of an infrared detector Dewar refrigeration assembly in an embodiment of the present invention;
FIG. 3 is an enlarged view of a portion of the structure at A in FIG. 2;
FIG. 4 is a schematic diagram of a refrigerator of an infrared detector Dewar refrigeration assembly in an embodiment of the present invention;
FIG. 5 is a schematic illustration of the dewar assembly of the infrared detector dewar refrigeration assembly in an embodiment of the present invention;
FIG. 6 is an exploded view of an infrared detector dewar refrigeration assembly in an embodiment of the present invention;
FIG. 7 is a schematic diagram of a push piston assembly height gauge in an embodiment of the present invention;
FIG. 8 is a schematic diagram of a standard height gauge in an embodiment of the present invention;
fig. 9 is an assembly view of the pushing piston assembly height gauge and the pushing piston assembly according to the embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
The embodiment of the invention provides a dead gap testing method for an infrared detector Dewar refrigeration assembly. As shown in fig. 2-5, infrared detector dewar refrigeration assembly 100 includes dewar assembly 110 and refrigerator 120 detachably connected, in other words, dewar assembly 110 is connected to refrigerator 120, and dewar assembly 110 is detachable from refrigerator 120. The pushing piston assembly 121 of refrigerator 120 is adapted to reciprocate within the cold finger 111 of dewar assembly 110, and the coupling surface of dewar assembly 110 is in contact with the coupling surface of refrigerator 120. It will be appreciated that dewar assembly 110 is coupled to refrigerator 120, that pusher piston assembly 121 extends into cold finger 111, and that the free end of pusher piston assembly 121 may be closer to or farther from the inner bottom wall of cold finger 111.
The infrared detector 300 (e.g., infrared focal plane detector) is the core optoelectronic device of infrared detection technology. The infrared detector 300 generally needs to work in a low temperature environment, which can reduce the noise of the infrared detector 300 and improve the sensitivity and resolution of the infrared detector 300.
Referring to fig. 1-5, the method for testing the dead gap of the infrared detector dewar refrigeration assembly comprises the following steps:
s1, the distance H1 between the coupling surface of dewar assembly 110 and the inner bottom wall of cold finger 111 was tested.
S2, the end face of the free end of the pushing piston assembly 121 is driven to move to the top dead center position, and the distance H2 between the end face of the free end of the pushing piston assembly 121 and the coupling surface of the refrigerator 120 is tested. The "top dead center position" is a position at which the end surface of the free end of push piston assembly 121 is located when the distance between the end surface of the free end of push piston assembly 121 and the inner bottom wall of cold finger 111 is the smallest during the movement of push piston assembly 121.
And S3, calculating the dead space 130 of the infrared detector Dewar refrigeration assembly 100 according to H1 and H2, wherein the dead space is H1-H2. The dead space 130 of the infrared detector dewar assembly 100, i.e., the push piston assembly dead space, is understood to be the minimum distance between the end surface of the free end of the push piston assembly 121 and the inner bottom wall of the cold finger 111 during the movement of the push piston assembly 121.
In operation of the IDDCA assembly, pusher piston assembly 121 reciprocates within cold finger 111. If Dewar assembly 110 and refrigerator 120 are not of the same size, it may cause the pushing piston assembly 121 of refrigerator 120 to interfere with cold finger 111 of Dewar assembly 110 causing impact, which in turn may cause infrared detector 300 to fail. Therefore, when refrigerator 120 is coupled to dewar assembly 110, it is necessary to test the minimum clearance between pushing piston assembly 121 and the bottom of cold finger 111, i.e., the distance from the top end (i.e., free end) of pushing piston assembly 121 to the inner bottom wall of cold finger 111 when pushing piston assembly 121 moves to the top dead center.
By adopting the embodiment of the invention, the dead clearance 130 of the pushing piston assembly 121 of the infrared detector Dewar refrigeration assembly 100 can be tested, the measuring method is simple in design and strong in operability, the interference problem possibly occurring when the refrigerator 120 is coupled with the Dewar assembly 110 can be effectively avoided, and the application level of the infrared detector Dewar refrigeration assembly 100 is improved.
On the basis of the above-described embodiment, various modified embodiments are further proposed, and it is to be noted herein that, in order to make the description brief, only the differences from the above-described embodiment are described in the various modified embodiments.
Referring to fig. 5, the testing of the distance H1 between the coupling face of the dewar assembly 110 and the inner bottom wall of the cold finger 111, according to some embodiments of the present invention, includes:
measuring the distance Ha between the end surface of Dewar assembly 110 near one end of pushing piston assembly 121 and the inner bottom wall of cold finger 111; the term "the end of the dewar assembly 110 close to the pushing piston assembly 121" as used herein means that the end of the dewar assembly 110 close to the pushing piston assembly 121 is formed after the dewar assembly 110 is assembled with the refrigerator 120.
Measuring a distance Hb between an end surface of the Dewar assembly 110 near one end of the pushing piston assembly 121 and a coupling surface of the Dewar assembly 110;
from Ha, Hb, the distance H1 between the coupling surface of dewar assembly 110 and the inner bottom wall of cold finger 111 is calculated. H1 ═ Ha-Hb.
Here, the tests for Ha and Hb can be measured with a vernier caliper or a depth gauge.
Referring to fig. 6-9, according to some embodiments of the present invention, the driving the end surface of the free end of the moving piston assembly 121 to move to the top dead center position, and testing a distance H2 between the end surface of the free end of the moving piston assembly 121 and the coupling surface of the refrigerator 120 includes:
fitting a dial gauge 211 to one end of a sleeve 212 forms a push piston assembly height gauge 210; for example, the sleeve 212 is open at both ends, and the dial indicator 211 may be provided at one open end of the sleeve 212 with the measuring rod of the dial indicator 211 extending into the sleeve 212. The object to be measured extends into the sleeve 212 from the other open end of the sleeve 212, the object to be measured drives the measuring rod to move, the movement of the measuring rod is amplified through the gear transmission in the dial indicator 211 to be changed into the rotation of the pointer on the dial, and therefore the size of the measured size is read.
Fitting the pushed piston assembly height gauge 210 to the standard height gauge 220, adjusting the pointer initial position of the dial gauge 211 based on the standard height gauge 220;
fitting a pushing piston assembly height gauge 210 to a pushing piston assembly 121;
removing the stator assembly 122 of the refrigerator 120, placing the magnetic member 230 on the rotor protection sleeve 123 of the refrigerator 120 and rotating along the periphery of the rotor protection sleeve 123 to drive the pushing piston assembly 121 to move;
when the end face of the free end of the pushing piston assembly 121 moves to the top dead center position, recording the reading of the dial indicator 211;
from the reading of the dial gauge 211, the distance H2 between the end face of the free end of the pushing piston assembly 121 and the coupling face of the refrigerator 120 is determined.
It should be noted that in the refrigerator 120 according to the embodiment of the present invention, the rotor protection sleeve 123 of the motor isolates the stator assembly 122 of the motor from other parts of the refrigerator 120, and the refrigerant is enclosed in the rotor protection sleeve 123 of the motor. The stator assembly 122 is removable.
The working medium gas of the refrigerator 120 is high-purity helium gas of 99.999%, and if the working medium is polluted to a certain degree, the performance of the refrigerator 120 is deteriorated, so that the refrigerator 120 fails. The main cause of contamination is the outgassing of the internal materials. A large amount of organic gases are discharged during the storage and operation of the refrigerator 120 due to the impregnating varnish of a large amount of epoxy glue and enameled wire used in the winding process of the motor stator assembly 122, and the gases are gradually condensed at the low-temperature end of the refrigerator 120, so that the performance of the heat regenerator is reduced, and the performance of the refrigerator 120 is reduced. Stator assembly 122 is the most important factor in contamination of chiller 120. By isolating the stator assembly 122, the refrigerant gas can be effectively prevented from being contaminated to ensure the performance of the infrared detector 300.
In some embodiments of the invention, the method further comprises:
before the pushing piston assembly height gauge 210 is assembled to the standard height gauge 220 and the pointer initial position of the dial gauge 211 is adjusted based on the standard height gauge 220, the standard height gauge 220 is prepared according to H1. For example, the length of the standard height gauge 220 may be equal to H1.
In some embodiments of the present invention, fitting the pushed piston assembly height gauge 210 to the standard height gauge 220, adjusting the initial position of the pointer of the dial gauge 211 based on the standard height gauge 220, comprises:
sleeving the sleeve 212 on the standard height gauge 220, and enabling the end face of the other end of the sleeve 212 to be flush with the zero scale of the standard height gauge 220;
recording the reading of the small dial of the dial indicator 211;
the reading of the large dial of the dial indicator 211 is zeroed.
As shown in fig. 9, in some embodiments of the present invention, fitting the pushing piston assembly height gauge 210 to the pushing piston assembly 121 includes:
the sleeve 212 is fitted around the pushing piston assembly 121, and the other end surface of the sleeve 212 is brought into contact with the coupling surface of the refrigerator 120.
In some embodiments of the present invention, the magnetic member 230 may be a magnet.
According to some embodiments of the invention, when the end face of the free end of the pusher piston assembly 121 moves to the top dead centre position, a reading of the dial indicator 211 is recorded, comprising:
during the movement of the pushing piston assembly 121, the reading of the dial indicator 211 is observed;
when the reading of the dial indicator 211 reaches a maximum value, the reading of the dial indicator 211 is recorded.
According to some embodiments of the present invention, the cryocooler 120 is a rotary integrated stirling cryocooler. Stirling refrigeration is one of the widely used refrigeration methods in the application of infrared detector 300 assembly. The rotary integrated Stirling refrigerator has the characteristics of compact structure, small volume, light weight, low power consumption and the like, can meet the high reliability requirements of various infrared detector 300 components, and becomes one of the most important choices of the infrared detector 300 components
The method for testing the dead gap of the infrared detector dewar refrigerating assembly according to the embodiment of the invention is described in detail in a specific embodiment with reference to fig. 2 to 9. It is to be understood that the following description is illustrative only and is not intended to be in any way limiting. All similar structures and similar variations thereof adopted by the invention are intended to fall within the scope of the invention.
In recent years, the infrared detection technology is rapidly developed, and an infrared focal plane detector assembly plays more and more important roles as a core photoelectric device of the infrared detection technology. The infrared detector generally needs to work in a low-temperature environment, and the low-temperature environment can reduce the noise of the infrared detector and improve the sensitivity and the resolution of the infrared detector. Stirling refrigeration is one of the widely used refrigeration methods in infrared detector applications. The rotary integrated Stirling refrigerator has the characteristics of compact structure, small volume, light weight, low power consumption and the like, can meet the high reliability requirements of various infrared detectors, and becomes one of the most important choices of the infrared detectors.
As shown in fig. 2-6, the rotary integrated stirling cryocooler is generally configured to use a dc brushless motor to drive a crankshaft and link mechanism to reciprocate, so as to implement a reverse stirling refrigeration cycle to complete refrigeration. In practice, it is desirable to couple the stirling cooler 120 and the dewar assembly 110(DDA assembly) together to form a complete infrared detector dewar refrigeration assembly 100(IDDCA assembly). During the operation of the IDDCA assembly, the push piston assembly 121 reciprocates within the cold finger 111 of the refrigerator 120. For the integrated dewar structure, the dewar cold finger is also the cold finger 111 of the refrigerator 120, and if the dewar assembly 110 and the refrigerator 120 are not matched in size, it may cause the pushing piston assembly 121 of the refrigerator 120 to interfere with the dewar cold finger 111 to cause impact, thereby causing the infrared detector 300 assembly to fail. Therefore, when refrigerator 120 is coupled to dewar assembly 110, it is necessary to test the minimum clearance between pushing piston assembly 121 of refrigerator 120 and the bottom of dewar cold finger 111, i.e. the distance from the top end of pushing piston assembly 121 to the bottom of dewar cold finger 111 when pushing piston assembly 121 of refrigerator 120 moves to the top dead center, i.e. dead gap 130 of refrigerator 120 according to the embodiment of the present invention. A schematic diagram of the coupling structure of the stirling cooler 120 and the dewar assembly 110 is shown in fig. 2.
The working medium gas of the rotary integrated Stirling refrigerator is high-purity helium with the purity of 99.999 percent, and if the working medium is polluted to a certain degree, the performance of the refrigerator is deteriorated, so that the failure of the refrigerator is caused. The main cause of contamination is the outgassing of the internal materials. A large amount of impregnating varnish of epoxy glue and enameled wires used in the winding process of a motor stator can emit a large amount of organic gases in the storage and working processes of a refrigerator, and the gases are gradually condensed at the low-temperature end of the refrigerator, so that the performance of a heat regenerator is reduced, and the performance of the refrigerator is reduced. The motor stator is the most important factor for contamination of the refrigerator. In order to solve the problem, in the design of the refrigerator 120, a motor stator isolation technology is adopted, that is, a motor stator assembly 122 is isolated from the whole machine through a rotor protective sleeve 123 of the motor, and a refrigeration working medium is sealed in the rotor protective sleeve 123 of the motor. This type of refrigerator 120 motor stator assembly 122 is conveniently detachable by being generally coupled to the body of the refrigerator 120 by screws. A schematic view of the stator assembly 122 of the chiller 120 is shown in fig. 6.
The embodiment of the invention is based on the dead gap test of the push piston assembly of the rotary integrated Stirling refrigerator, and is used for the rotary integrated Stirling refrigerator with the detachable motor stator.
When the rotary integrated stirling cooler is coupled to the infrared detector dewar assembly, there are differences between individuals due to the different coolers and infrared detector dewar assemblies, and they may be from different vendors. If the refrigerator dead clearance measurement is not carried out, the interference between the refrigerator pushing piston assembly and the Dewar cold finger can be caused. And (4) testing the refrigerator dead clearance, wherein the depth from the coupling surface to the bottom of the Dewar cold finger and the distance from the top end of the pushing piston assembly to the coupling surface when the pushing piston assembly of the refrigerator moves to the top dead center need to be measured. The sliding piston assembly belongs to a moving part and has no radial constraint, so that the sliding piston assembly is difficult to measure. Therefore, it is very important to establish an effective method for testing the dead clearance of the refrigerator.
The dead gap test method of the infrared detector Dewar refrigeration assembly provided by the embodiment of the invention comprises the following steps:
firstly measuring the distance Ha from the end face of the Dewar component 110 to the bottom surface of the cold finger 111 by a vernier caliper or a depth gauge;
measuring a dewar assembly 110 end-to-coupling plane distance Hb;
the difference Ha-Hb, the depth H1 of the coupling face of dewar assembly 110 to the bottom face of cold finger 111, is calculated.
Push piston assembly 121 of test refrigerator 120 moves to a top dead center position to coupling surface distance H2;
the dead gap 130 of the refrigerator 120 is obtained by calculating H1-H2.
The dead-space 130 of the cryocooler 120 is compared to the safe distance to determine whether the cryocooler 120 can be coupled to the dewar assembly 110.
In testing H2, a tooling set was designed that included a standard height gauge 220 (shown in fig. 8) and a push piston assembly height gauge 210 (shown in fig. 7), the push piston assembly height gauge 210 being implemented by screwing a dial gauge 211 onto the sleeve 212. The pushing piston assembly height gauge 210 is arranged on the pushing piston assembly 121, the bottom surface of the sleeve 212 reaches the coupling surface of the refrigerator 120, and the small magnet rotates on the periphery of the motor rotor protective sleeve 123 to drive the pushing piston assembly 121 to reciprocate so as to drive the dial indicator 211 to indicate and change, so that the H2 size measurement is realized.
The measurement method is simple in design and strong in operability, can effectively avoid the interference problem which can occur when the Stirling refrigerator 120 is coupled with the Dewar assembly 110, and improves the application level of the IDDCA assembly.
Taking a certain medium wave 640 × 512 infrared detector 300 component as an example, the detailed implementation manner is as follows: the distance Ha from the end face of the Dewar assembly 110 to the bottom surface of the cold finger 111 is measured by a vernier caliper or a depth gauge, then the distance Hb from the end face of the Dewar assembly 110 to the coupling surface is measured, and the difference Ha-Hb between the two is calculated, namely H1. A standard height gauge 220 is designed to have a height of 60.500mm, which generally coincides with or is close to the nominal distance from the coupling surface of dewar assembly 110 to the bottom surface of cold finger 111 (H1), which facilitates measurement. A dial indicator 211 is fixed to the sleeve 212 by screws to form a push piston assembly height gauge 210. The pusher piston assembly height gauge 210 is mounted on the standard height gauge 220 and the reading of the small scale of the dial gauge 211 is recorded and the reading of the large scale of the outer ring is zeroed. And locking the dial of the outer ring, and not rotating in the subsequent measuring process. The pushing piston assembly height gauge 210 is mounted on the pushing piston assembly 121 until the bottom surface of the sleeve 212 reaches the coupling surface of the refrigerator 120 and ensures that the bottom surface of the sleeve 212 is in full contact with the coupling surface of the refrigerator 120. And (3) taking down the stator of the motor, rotating the surface of the protective sleeve 123 of the motor rotor of the refrigerator 120 by using a small magnet until the dial indicator 211 reaches the maximum displacement, and recording the actual reading of the dial indicator 211, wherein the actual reading is the distance H2 from the coupling surface of the refrigerator 120 when the piston assembly 121 is pushed to move to the top dead center. A schematic of the H2 measurement is shown in fig. 9. If H1-H2 is more than or equal to 0.1mm, the mark is qualified. If the value is less than 0.1mm or even negative, there may be a problem of the pushing piston assembly 121 hitting the bottom end of the cold finger 111, and the refrigerator 120 cannot be coupled to the dewar assembly 110 as being rejected.
It should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention, and those skilled in the art can make various modifications and changes. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
As shown in fig. 7 to 9, an embodiment of the present invention further provides a dead gap testing tool for an infrared detector dewar refrigeration assembly, including:
a standard height gauge 220;
the push piston assembly height gauge 210 includes a dial indicator 211 and a sleeve 212, the dial indicator 211 is disposed at one end of the sleeve 212, and the push piston assembly height gauge 210 may be assembled to the standard height gauge 220 to adjust an initial position of a pointer of the dial indicator 211.
By adopting the embodiment of the invention, the dead clearance 130 of the pushing piston assembly 121 of the infrared detector Dewar refrigeration assembly 100 can be tested, the measuring method is simple in design and strong in operability, the interference problem possibly occurring when the refrigerator 120 is coupled with the Dewar assembly 110 can be effectively avoided, and the application level of the infrared detector Dewar refrigeration assembly 100 is improved.
It should be noted that in the description of the present specification, reference to the description of the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples", etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims (9)
1. The method for testing the dead gap of the infrared detector Dewar refrigeration assembly is characterized in that the infrared detector Dewar refrigeration assembly comprises a Dewar assembly and a refrigerator which are detachably connected, a pushing piston assembly of the refrigerator is suitable for reciprocating motion in a cold finger of the Dewar assembly, and a coupling surface of the Dewar assembly is in contact with a coupling surface of the refrigerator;
the method comprises the following steps:
testing the distance H1 between the coupling surface of the dewar assembly and the inner bottom wall of the cold finger;
driving the end face of the free end of the pushing piston assembly to move to a top dead center position, and testing the distance H2 between the end face of the free end of the pushing piston assembly and the coupling surface of the refrigerator;
calculating the dead space H1-H2 of the infrared detector Dewar refrigeration assembly according to the H1 and the H2;
the step of driving the end face of the free end of the pushing piston assembly to move to a top dead center position, and testing the distance H2 between the end face of the free end of the pushing piston assembly and the coupling surface of the refrigerator comprises the following steps:
assembling the dial indicator to one end of the sleeve to form a pushing piston assembly height gauge;
fitting the pushed piston assembly height gauge to a standard height gauge, adjusting the dial gauge pointer initial position based on the standard height gauge;
fitting the pushing piston assembly height gauge to the pushing piston assembly;
dismantling a stator assembly of the refrigerator, placing a magnetic piece on a rotor protective sleeve of the refrigerator and rotating along the periphery of the rotor protective sleeve so as to drive the pushing piston assembly to move;
when the end face of the free end of the pushing piston assembly moves to the top dead center position, recording the reading of the dial indicator;
and determining the distance H2 between the end surface of the free end of the pushing piston assembly and the coupling surface of the refrigerator according to the reading of the dial indicator.
2. The method of claim 1, wherein said testing a distance H1 between a coupling surface of the dewar assembly and an inner bottom wall of the cold finger comprises:
measuring the distance Ha between the end surface of the Dewar assembly close to one end of the pushing piston assembly and the inner bottom wall of the cold finger;
measuring a distance Hb between an end surface of the Dewar assembly close to one end of the pushing piston assembly and a coupling surface of the Dewar assembly;
calculating the distance H1 between the coupling surface of the Dewar assembly and the inner bottom wall of the cold finger according to the Ha and the Hb.
3. The method of claim 1, further comprising:
preparing a standard height gauge according to the H1 before assembling the pushed piston assembly height gauge to the standard height gauge, adjusting the initial position of the pointer of the dial gauge based on the standard height gauge.
4. The method of claim 1, wherein said fitting said pushed piston assembly height gauge to a standard height gauge, adjusting an initial position of a pointer of said dial gauge based on said standard height gauge comprises:
sleeving the sleeve on the standard height gauge in a sleeved mode, and enabling the end face of the other end of the sleeve to be flush with the zero scale of the standard height gauge;
recording the reading of a small dial of the dial indicator;
and zeroing the reading of the large dial of the dial indicator.
5. The method of claim 1, wherein said fitting said push piston assembly height gauge to said push piston assembly comprises:
and sleeving the sleeve on the pushing piston assembly in a sleeving manner, and enabling the end face of the other end of the sleeve to be in contact with the coupling surface of the refrigerator.
6. The method of claim 1, wherein the magnetic member is a magnet.
7. The method of claim 1, wherein recording readings of said dial indicator as the end face of the free end of said pusher piston assembly moves to a top dead center position comprises:
observing the reading of the dial indicator during the movement of the pushing piston assembly;
and when the reading of the dial indicator reaches the maximum value, recording the reading of the dial indicator.
8. The method of claim 1, wherein the chiller is a rotary integrated stirling chiller.
9. The tool is characterized in that the infrared detector Dewar refrigeration assembly comprises a Dewar assembly and a refrigerator which are detachably connected, a pushing piston assembly of the refrigerator is suitable for reciprocating in a cold finger of the Dewar assembly, and a coupling surface of the Dewar assembly is in contact with a coupling surface of the refrigerator;
infrared detector dewar refrigeration subassembly's dead gap test fixture includes:
a standard height gauge;
the pushing piston assembly height gauge comprises a dial indicator and a sleeve, the dial indicator is arranged at one end of the sleeve, and the pushing piston assembly height gauge can be assembled to the standard height gauge so as to adjust the initial position of a pointer of the dial indicator;
said pusher piston assembly height gauge adapted to fit to said standard height gauge to adjust an initial position of a pointer of said dial gauge based on said standard height gauge;
the pushing piston assembly height gauge after the initial position of the pointer of the dial indicator is adjusted is suitable for being assembled to the pushing piston assembly, after a stator assembly of the refrigerator is disassembled, a magnetic piece is placed on a rotor protective sleeve of the refrigerator and rotates along the periphery of the rotor protective sleeve to drive the pushing piston assembly to move, when the end face of the free end of the pushing piston assembly moves to the top dead center position, the reading of the dial indicator is recorded, so that the distance H2 between the end face of the free end of the pushing piston assembly and the coupling face of the refrigerator is determined according to the reading of the dial indicator, and the dead clearance H1-H2 of the infrared detector Dewar refrigeration assembly is calculated by combining the distance H1 between the coupling face of the Dewar assembly and the inner bottom wall of the cold finger.
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