CN111854210A

CN111854210A - Low-temperature refrigerator with rotation-proof mechanism

Info

Publication number: CN111854210A
Application number: CN202010796702.0A
Authority: CN
Inventors: 李奥; 周志坡; 钱继峰; 刁俊杰; 葛金宏; 吴兴旺
Original assignee: Csic Pride Nanjing Cryogenic Technology Co ltd; China State Shipbuilding Corp Ltd
Current assignee: Csic Pride Nanjing Cryogenic Technology Co ltd; China State Shipbuilding Corp Ltd
Priority date: 2020-08-10
Filing date: 2020-08-10
Publication date: 2020-10-30

Abstract

The invention discloses a low-temperature refrigerator with an anti-rotation mechanism, which comprises a cover body (2), wherein an accommodating cavity (23) for accommodating a mouth-shaped window (5 c) which can reciprocate up and down in a connecting rod (5) is arranged in the cover body (2), at least two anti-rotation mechanisms (19) which protrude from the wall surface of the accommodating cavity (23) are arranged on the wall surface of the accommodating cavity (23) which is opposite to a flat plane formed by a vertical surface (53) and a horizontal surface (52) of the outer side wall of a mouth-shaped cavity in the mouth-shaped window (5 c), the free end surface of each anti-rotation mechanism (19) is always in contact connection with the vertical surface (53), and the anti-rotation mechanisms (19) can act on the mouth-shaped window (5 c) in a rectangular mode with opposite acting force. The anti-rotation mechanism is arranged in the cover body and is not contacted with the external environment, the problem of airtight leakage of the guide pin arranged in the traditional structure is solved, the risk of refrigerant working medium leakage is reduced, and the anti-rotation mechanism is simple in structure and low in processing cost.

Description

Low-temperature refrigerator with rotation-proof mechanism

Technical Field

The invention belongs to the technical field of cryogenic refrigerators, and particularly relates to a cryogenic refrigerator with an anti-rotation mechanism, which can prevent a connecting rod mechanism from rotating.

Background

A cryogenic refrigerator, typified by a Gifford-McMahon (GM) refrigerator, has an expander and a compressor of a working gas (also referred to as a refrigerant gas). Fig. 1 shows a refrigerator of this type. The high-pressure air flow discharged from the compressor 1 enters a pushing piston 10 which is arranged in a cylinder 13 and reciprocates up and down through an air distribution mechanism RV (an air distribution valve 6 and a rotary valve 7), exchanges heat with a cold storage material 10c, then does work and expands in an expansion cavity 9, flows out of the air distribution mechanism through the pushing piston 10, and returns to a low-pressure cavity of the compressor 1. Through the continuous circulation process, the refrigeration effect is formed.

A flat rotary valve comprising two main components: a rotary valve 7 and a distributing valve 6, wherein one part is made of resin wear-resistant material, and the other part is made of metal material. When the air distribution valve works, the planes of the two components are attached to each other, and the communication states of the channels on the rotary valve 7 and the air distribution valve 6 are switched through the rotation of the rotary valve 7 arranged on the bearing 14, so that the switching of high-pressure air flow and low-pressure air flow is realized.

A connecting rod 5, comprising: the mouthpiece-shaped window 5c has a flat hexagonal structure having a central square hole and consisting of a horizontal surface 52 and a vertical surface 53, and a driving surface 51 and a side wall surface 54 which are in contact with the outer peripheral surface of the driving sleeve 100, and is in the form of a thin plate structure formed of a main body surface consisting of the horizontal surface 52 and the vertical surface 53. The upper and

lower drive shafts

5a, 5b shown in fig. 9 are coaxially connected at their centers to outer side surfaces (not specifically shown in fig. 9) opposite to the upper and lower contact surfaces 51.

The motor 12 drives the cam 3 with the cam handle 31 eccentrically mounted thereon to rotate around the central axis O at a constant speed, and the cam handle 31 is inserted into the blind hole type insertion hole 74 on the back surface 75 of the rotary valve 7 to drive the rotary valve 7 to rotate, as shown in fig. 2. Meanwhile (as shown in fig. 7), the cam shank 31 passes through an inner peripheral center hole of a cylindrical driving sleeve 100 made of a resin material, so that the driving sleeve 100 rotates about the center axis O of the cam 3 while the outer peripheral surface of the driving sleeve 100 is brought into direct contact with the upper and lower driving surfaces 51 of the mouth-shaped window 5c of the link 5. The upper and

lower driving shafts

5a and 5b are fixedly installed in the housing 2 in the radial direction by the guide sleeve 4 and can move only up and down (i.e., move in the directions Z1-Z2). The axial center of the driving sleeve 100 makes a uniform circular motion around the central axis O, and the size of the hole in the center direction of the mouth-shaped window 5c along the X-axis direction is much larger than the size along the Z-axis direction, so that the hole is not limited in the X-direction. However, in the Z-axis direction, the driving sleeve 100 contacts the driving surface 51 of the mouth-shaped window 5c, thereby moving the rising rod 5 up and down in a reciprocating manner in a sinusoidal manner, thereby moving the pushing piston 10 in the cylinder 13 along the Z-axis.

The connecting rod 5 does not generate X, Y-directional displacement in the up-and-down reciprocating motion, but does not restrict the rotation with the Z axis as the central axis, the mouth-shaped window 5c of the connecting rod 5 rotates, the cover body 2 is worn by the contact with the accommodating cavity 23, and a large amount of metal debris is generated; or the driving sleeve 100 is reduced in contact with the driving surface 51 of the mouth-shaped window 5c and even falls out of the square hole of the mouth-shaped window 5c, and mechanical failure occurs.

Fig. 3 is a partial schematic view of a conventional cryocooler with an anti-rotation mechanism shown in a cross-sectional direction of C-C in fig. 1, and fig. 4 is a partial enlarged structural view of fig. 3, both showing the conventional anti-rotation mechanism. The side wall of the cover body 2 is provided with a threaded hole 24 and a guide pin 200. In the implementation process, a downward through opening groove 55 is processed on the side wall surface 54 of the mouth-shaped window 5c, the guide pin 200 comprises a pin head 203, a pin body 201 and a pin tail 202, the size of the pin head 203 is slightly smaller than that of the opening groove 55, the pin head 203 is inserted into the opening groove 55, the pin body 201 is processed into a threaded assembly and matched with the threaded hole 24, and the pin tail 202 and the cover body 2 are hermetically installed through a sealing ring 300. The overall process is relatively complex and risks of leakage of the refrigerant working medium.

Disclosure of Invention

The invention aims to provide a low-temperature refrigerator with a rotation prevention mechanism, which can prevent a connecting rod mechanism from rotating, aiming at the problems in the prior art.

The invention aims to solve the problems by the following technical scheme:

a low-temperature refrigerator with an anti-rotation mechanism comprises a cover body, wherein an accommodating cavity for accommodating a mouth-shaped window capable of reciprocating up and down in a connecting rod is arranged in the cover body, and the low-temperature refrigerator is characterized in that: the wall surface of the containing cavity opposite to a flat plane formed by a vertical surface of the outer side wall of the mouth-shaped cavity in the mouth-shaped window and a horizontal plane is provided with at least two anti-rotation mechanisms protruding out of the wall surface, the free end surface of each anti-rotation mechanism is always in contact connection with the vertical surface, and the anti-rotation mechanisms can act on the mouth-shaped window in an opposite acting force rectangular manner; when the concentric axis Z of the upper driving shaft and the lower driving shaft is a rotating shaft, the anti-rotation mechanism can act on the mouth-shaped window in an opposite acting force rectangular mode, and the mouth-shaped window is always in contact connection with the vertical surface in the vertical reciprocating motion process.

The anti-rotation mechanism is a round bar structure, and the axial direction of the anti-rotation mechanism is perpendicular to a flat plane formed by the vertical plane and the horizontal plane.

And the fixed tail end of the anti-rotation mechanism is fixedly arranged on the wall surface of the accommodating cavity.

The cover body is internally provided with a mounting hole which is positioned on the wall surface of the containing cavity and used for mounting the anti-rotation mechanism, and the fixed tail end of the anti-rotation mechanism is inserted into the mounting hole for fixing.

When the mounting holes are located on the same side wall surface of the containing cavity where the mouth-shaped window is located, the two mounting holes are respectively arranged corresponding to the two vertical surfaces on the same side of the same flat plane formed by the vertical surface and the horizontal plane, so that the free end surface of the anti-rotation mechanism is respectively abutted against the two vertical surfaces.

The distance between the axial leads of the two anti-rotation mechanisms is not less than the minimum distance between the two vertical surfaces on the same side on the same flat plane.

When the mounting holes are positioned on the wall surface of the different side of the containing cavity where the mouth-shaped window is positioned, the two mounting holes are respectively arranged corresponding to the two vertical surfaces of the different sides on the two flat planes formed by the vertical surfaces and the horizontal plane, and the axial lines of the mounting holes are positioned on the same central axis, so that the free end surfaces of the anti-rotation mechanisms are symmetrically abutted against the two vertical surfaces.

The mounting hole is a blind hole.

The anti-rotation mechanism is made of wear-resistant plastics.

Compared with the prior art, the invention has the following advantages:

the anti-rotation mechanism is arranged in the cover body and is not contacted with the external environment, the problem of airtight leakage of the guide pin arranged in the traditional structure is solved, the risk of refrigerant working medium leakage is reduced, and the anti-rotation mechanism is simple in structure and low in processing cost.

Drawings

FIG. 1 is a schematic view showing the constitution of a cryocooler according to the present invention;

FIG. 2 is a schematic three-dimensional structure of a valve train;

FIG. 3 is a partial schematic view of a conventional cryocooler with an anti-rotation mechanism shown in cross-section C-C in FIG. 1;

FIG. 4 is an enlarged partial schematic view of FIG. 3;

FIG. 5 is a schematic structural diagram of a first embodiment of a cryocooler having an anti-rotation mechanism according to the present invention shown in cross-section C-C in FIG. 1;

FIG. 6 is an enlarged schematic view of a portion of the anti-rotation mechanism of FIG. 5;

FIG. 7 is a schematic view of the cross-sectional A-A configuration of FIG. 6;

FIG. 8 is a schematic view of the cross-sectional B-B structure of FIG. 6;

FIG. 9 is a schematic three-dimensional view of the cam and link portion of FIG. 5;

FIG. 10 is a schematic structural view of a second embodiment of the cryocooler having an anti-rotation mechanism of the present invention.

Wherein: 1-a compressor; 1 a-a high pressure exhaust duct; 1 b-a low pressure suction duct; 2, a cover body; 21-cover body air hole; 22 — a low pressure path; 23-a containment chamber; 24-a threaded hole; 25-mounting holes; 3, a cam; 31-eccentric cam handle; 4, a guide sleeve; 5, connecting rods; 51-a drive face; 52-horizontal plane; 53-vertical plane; 54 — side wall face; 55-open slot; 5a — an upper drive shaft; 5b — a lower drive shaft; 5 c-a mouth-shaped window; 6-distributing valve; 61-gas distribution valve face; 62-high pressure vent; 63-air hole of air distribution valve; 7-a rotary valve; 71-low pressure hole; 72-high pressure tank; 73 — switching plane; 74-a jack; 75 — back; 8-a thermal chamber; 9-an expansion chamber; 10-pushing piston; 10 a-front hole of piston; 10 b-piston rear bore; 10 c-cold storage material; 12-a motor; 13-a cylinder; 14-a bearing; 15-a spring; 16-valve body locating pin; 19-means for preventing rotation in the technology of the present invention; 100-a driving sleeve; 200-a guide pin; 201-pin body; 202-pin head; 203-pin tail; 300-sealing ring.

Detailed Description

The invention is further described with reference to the following figures and examples.

As shown in fig. 1: the low-temperature refrigerator comprises a compressor 1, a cover body 2, a cylinder 13 and a pushing piston 10, wherein a motor 12 and a driven cam 3 are arranged in the cover body 2; the eccentric cam handle 31 of the cam 3 drives the connecting rod 5 to convert the rotary motion into the up-and-down reciprocating motion, thereby driving the pushing piston 10 to move up and down in the cylinder 13. The air distribution mechanism RV consists of an air distribution valve 6 and a rotary valve 7. The gas distribution valve 6 is mounted in the housing 2, fixed therein by a valve body positioning pin 16, and arranged coaxially with the rotary valve 7. The cam shank 31 rotates the rotary valve 7 mounted on the bearing 14 along the rotation axis. The compressor 1 sucks and compresses refrigerant gas to discharge the refrigerant gas as high-pressure refrigerant gas; the high-pressure discharge pipe 1a supplies the high-pressure refrigerant gas to the cover 2, and the high-pressure refrigerant gas is transferred to the high-pressure groove 72 of the rotary valve 7, which is hermetically bonded to the high-pressure gas through the high-pressure gas hole 62 on the center axis of the gas distribution valve 6, and the high-pressure groove 72 is not communicated with the low-pressure hole 71. The rotary valve 7 is provided with a low pressure hole 71, and the low pressure hole 71 is communicated with the low pressure passage 22 in the cover body 2. The high pressure groove 72 extends radially outward along the rotation axis O and is eccentrically disposed on the rotary valve 7. The low pressure hole 71 is disposed opposite the high pressure groove 72 on the other side of the axis O.

In the position shown in figure 1 in combination with figure 2. The low-pressure hole 71 is in overlapped communication with the air distribution valve air hole 63 on the air distribution valve 6; at this moment, the low pressure hole 71 on the rotary valve 7, the gas distribution valve air hole 63 on the gas distribution valve 6 and the cover body air hole 21 on the cover body 2 are communicated, the system is in a low pressure exhaust stage, gas in the expansion cavity 9 is changed from high pressure to low pressure, and flows out through the piston rear hole 10b, the cold storage material 10c and the piston front hole 10a on the push piston in sequence and returns to the low pressure air suction pipeline 1b of the compressor 1. When the rotary valve 7 rotates a certain angle, the low pressure hole 71 is not communicated with the air distribution valve air hole 63 on the air distribution valve 6, and becomes a high pressure groove 72 on the rotary valve 7 to be communicated with the air distribution valve air hole 63 on the air distribution valve 6 (the matching relation is not shown), at this moment, the high pressure gas discharged by the compressor 1 enters the cylinder 13 through the high pressure air hole 62 on the air distribution valve 6 and the high pressure groove 72 on the rotary valve 7 communicated with the air distribution valve, and enters the expansion chamber 9 through the piston front hole 10a on the push piston, the cold storage material 10c and the piston rear hole 10b in sequence. In the above process, the high pressure gas discharged from the compressor 1 acts on the rear surface of the distribution valve 6, and the distribution valve 6 is tightly attached to the rotary valve 7 by the positive pressure on the rear surface and the elastic force of the spring 15 to form an airtight sliding contact surface. The rotary valve 7 and the gas distributing valve 6 are both designed as a revolving body structure along the rotation axis, wherein the rotary valve 7 is rotatably supported by a bearing 14 and is arranged in the cover body 2; the gas distribution valve 6 is disposed coaxially with the rotary valve 7 in the cover body 2, and the gas distribution valve 6 is fixed by a valve body positioning pin 16 so as not to be rotatable but detachable in the axial direction of the center axis O.

The connecting rod 5 is composed of an upper drive shaft 5a, a lower drive shaft 5b and a mouth-shaped window 5c in the middle. The mouth-shaped window 5c is of a flat cuboid structure and is internally provided with a rectangular cavity, and the mouth-shaped window 5c can be accommodated in the accommodating cavity 23 of the cover body 2. The guide sleeve 4 is mounted in the cover body 2, coaxially fixed to the outer peripheries of the upper drive shaft 5a and the lower drive shaft 5b, and radially restricted, but does not restrict the rotational movement of the upper drive shaft 5a and the lower drive shaft 5b about the concentric axis Z.

The structure of the link 5 will be described in detail by taking fig. 9 as an example. The concentric axis of the upper drive shaft 5a and the lower drive shaft 5b is a Z axis, the rotation axis O of the cam 3 is a Y axis, a rectangular cavity penetrating along the Y axis is processed on the maximum surface formed by the horizontal surface 52 and the vertical surface 53 and perpendicular to the Y axis, the inner wall of the cavity forms a drive surface 51, and the dimension of the cavity along the Z axis direction is far smaller than the distance between two opposite sides along the X axis direction. The outer diameter of the driving sleeve 100 is equal to the distance between the driving surfaces 51 parallel to each other in the Z-axis direction. When the cam 3 is rotated, the eccentric cam shank 31 is rotated along the rotation axis O through the center hole of the resin-made driving sleeve 100, and the outer periphery of the driving sleeve 100 comes into contact with the driving surface 51, forming a displacement component in the Z1 direction or the Z2 direction (up-down direction) along the Z-axis direction, while being restricted in the Z-axis direction and not restricted in the X-axis direction. Therefore, the entire mouth-shaped window 5c forms a sinusoidal motion reciprocating up and down along the Z axis. Thereby causing the push piston 10 connected to the lower driving shaft 5b to reciprocate up and down along the Z-axis.

The technical scheme of the invention is explained in detail in the following with the accompanying drawings,

example one

Fig. 5 is a structural schematic view of a first embodiment of a cryocooler having an anti-rotation mechanism according to the present invention, which is shown in a sectional direction of C-C in fig. 1, fig. 6 is an enlarged schematic view of a portion of the anti-rotation mechanism in fig. 5, fig. 7 is a schematic view of a sectional structure of a-a in fig. 6, fig. 8 is a schematic view of a sectional structure of B-B in fig. 6, and fig. 9 is a schematic view of a three-dimensional structure of a cam and link portion in fig. 5.

As shown in fig. 5, 7, 8, and 9, in the implementation, two mounting holes 25 to which the rotation preventing mechanism 19 for preventing the rotation of the link 5 is attached are formed in the cover body 2 at positions symmetrical to the rotation axis O (Y axis) on the X axis. The flat plane formed by the horizontal plane 52 and the vertical plane 53 of the mouthpiece-shaped window 5c is perpendicular to the Y-axis, and the same side wall surface of the housing chamber 23 facing the flat plane is penetrated by the two mounting holes 25. The anti-rotation mechanism 19 is a round bar structure and is installed in the installation hole 25, the axial direction of the anti-rotation mechanism 19 is vertically crossed with a flat plane formed by a horizontal plane 52 and a vertical plane 53 of the mouth-shaped window 5c, and the anti-rotation mechanism protrudes out of the same side wall surface of the accommodating cavity 23. And the axial center distance of the two mounting holes 25 along the X-axis direction is approximately equal to the center distance of the two vertical surfaces 53 on the same flat plane, and the anti-rotation mechanism 19 is always in contact with the two vertical surfaces 53 during the vertical reciprocating motion of the mouth-shaped window 5c along the Z-axis.

Further explaining the technical characteristics of the technical scheme of the invention.

Fig. 6 is an example, when the link 5 rotates about the Z-axis, that is, the flat plane formed by the horizontal plane 52 and the vertical plane 53 of the mouth-shaped window 5c rotates clockwise about the Z-axis; the vertical surface 53 on the + X side will press the anti-rotation mechanism 19 near the + X side to move in the-Y direction; since the mounting hole 25 is a blind hole, the rotation preventing mechanism 19 cannot move in the-Y axis direction, and the rotation preventing mechanism 19 contacting the vertical surface 53 will generate a moment in the "counterclockwise" direction with the Z axis as the rotation axis to the link 5. On the contrary, when the flat plane formed by the horizontal plane 52 and the vertical plane 53 of the mouth-shaped window 5c rotates counterclockwise along the Z-axis, the vertical plane 53 on the-X side presses the anti-rotation mechanism 19 close to the-X side and moves in the-Y direction; similarly, the mounting hole 25 near the-X side is also a blind hole, and the anti-rotation mechanism 19 near the-X side contacts the vertical surface 53 near the-X side to generate a moment in a clockwise direction with the Z axis as a rotating shaft. The link 5 is limited to form rotation in the Z-axis by the two anti-rotation mechanisms 19 mounted as described above.

In general, the anti-rotation mechanism 19 is a round bar structure, and can be made of wear-resistant plastic material, so as to prevent metal abrasion with the vertical surface 53 of the metal connecting rod 5.

The mounting hole 25 is in the form of a blind hole structure. To explain further, the side close to the accommodating chamber 23 is a wall surface with an opening structure opposite to the flat plane formed by the vertical surface 53 and the horizontal surface 52. On the other side, the blind hole can be directly processed, and a structure with the function of the blind hole can also be formed by other structural forms. For example, as illustrated in fig. 5, before the motor 12 is connected to the cover 2, a through hole is formed from one side of the motor 12 in the mounting direction toward the accommodating cavity 23 of the cover 2, and when the motor 12 is connected to the cover 2, a plug or a blind plate is mounted on one side of the through hole away from the accommodating cavity 23, and the through hole is configured as a blind hole.

Example two

Fig. 10 is another embodiment of the present invention, which will be described in detail below.

The mounting holes 25 in the first embodiment are formed in the same side wall of the receiving cavity 23, or in the opposite wall according to the manner shown in fig. 10. Specifically, two mounting holes 25 are formed in one side of the X-axis, two holes of wall surfaces of the accommodating cavity 23 are formed along the Y-axis as the mounting holes 25, and two anti-rotation mechanisms 19 are respectively mounted in the mounting holes 25, wherein the rear end surfaces of the two anti-rotation mechanisms 19 respectively abut against the bottom of the corresponding mounting holes 25, the front end surfaces of the two anti-rotation mechanisms 19 are oppositely arranged, and the two anti-rotation mechanisms respectively abut against two flat planes formed by the vertical surfaces 53 and the horizontal surface 52 at two sides of the mouth-shaped window 5 c.

The low-temperature refrigerator with the anti-rotation mechanism comprises a gas distribution mechanism RV, wherein a gas distribution valve 6 of the gas distribution mechanism is eccentrically fixed on a cover body 2 through a valve body positioning pin 16; the rotary valve 7 of the valve train is positioned in the housing 2 by means of a bearing 14. The cryocooler is not limited to gifford-mcmahon coolers, solvin coolers, pulse tube coolers, etc.

The above embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby, and any modification made on the basis of the technical scheme according to the technical idea proposed by the present invention falls within the protection scope of the present invention; the technology not related to the invention can be realized by the prior art.

Claims

1. A low-temperature refrigerator with an anti-rotation mechanism comprises a cover body (2), wherein an accommodating cavity (23) for accommodating a mouth-shaped window (5 c) which can reciprocate up and down in a connecting rod (5) is arranged in the cover body (2), and the low-temperature refrigerator is characterized in that: at least two anti-rotation mechanisms (19) protruding from the wall surface of the accommodating cavity (23) opposite to a flat plane formed by a vertical surface (53) of the outer side wall of the mouth-shaped cavity and a horizontal surface (52) in the mouth-shaped window (5 c) are arranged, the free end surface of each anti-rotation mechanism (19) is always in contact connection with the vertical surface (53), and the anti-rotation mechanisms (19) can act on the mouth-shaped window (5 c) in a rectangular manner by opposite acting force; when the concentric axis Z of the upper driving shaft (5 a) and the lower driving shaft (5 b) is a rotating shaft, the anti-rotation mechanism (19) can act on the mouth-shaped window (5 c) in a rectangular mode by opposite acting force, and the mouth-shaped window (5 c) is always kept in contact connection with the vertical surface (53) in the vertical reciprocating process.

2. The cryocooler with an anti-rotation mechanism according to claim 1, wherein: the anti-rotation mechanism (19) is of a round bar structure, and the axial direction of the anti-rotation mechanism (19) is perpendicular to a flat plane formed by the vertical plane (53) and the horizontal plane (52).

3. The cryocooler with an anti-rotation mechanism according to claim 1 or 2, wherein: the fixed tail end of the anti-rotation mechanism (19) is fixedly arranged on the wall surface of the accommodating cavity (23).

4. The cryocooler with an anti-rotation mechanism according to claim 1 or 2, wherein: the anti-rotation device is characterized in that a mounting hole (25) which is located on the wall surface of the containing cavity (23) and used for mounting the anti-rotation mechanism (19) is formed in the cover body (2), and the fixed tail end of the anti-rotation mechanism (19) is inserted into the mounting hole (25) to be fixed.

5. The cryocooler with an anti-rotation mechanism according to claim 4, wherein: when the mounting holes (25) are positioned on the same side wall surface of the accommodating cavity (23) where the mouth-shaped window (5 c) is positioned, the two mounting holes (25) are respectively arranged corresponding to the two vertical surfaces (53) on the same side on the same flat plane formed by the vertical surface (53) and the horizontal surface (52), so that the free end surfaces of the anti-rotation mechanism (19) are respectively abutted against the two vertical surfaces (53).

6. The cryocooler with an anti-rotation mechanism according to claim 5, wherein: the distance between the axial leads of the two anti-rotation mechanisms (19) is not less than the minimum distance between the two vertical surfaces (53) on the same side on the same flat plane.

7. The cryocooler with an anti-rotation mechanism according to claim 4, wherein: when the mounting holes (25) are positioned on the wall surface on the different side of the accommodating cavity (23) where the mouth-shaped window (5 c) is positioned, the two mounting holes (25) are respectively arranged corresponding to the two vertical surfaces (53) on the different sides of the two flat planes formed by the vertical surfaces (53) and the horizontal plane (52), and the axial lines of the mounting holes (25) are positioned on the same central axis, so that the free end surfaces of the anti-rotation mechanisms (19) are symmetrically abutted against the two vertical surfaces (53).

8. The cryocooler with an anti-rotation mechanism according to claim 4, wherein: the mounting hole (25) is a blind hole.

9. The cryocooler with an anti-rotation mechanism according to claim 1, wherein: the anti-rotation mechanism (19) is made of wear-resistant plastics.