阅读说明：本技术 一种阀门机构及采用该阀门机构的低温制冷机 (Valve mechanism and cryogenic refrigerator adopting same ) 是由 李奥 周志坡 查子文 蔡旭东 查健 于 2020-08-10 设计创作，主要内容包括：本发明公开了一种阀门机构,包括旋转阀(7)和配气阀(6)构成的配气机构,该配气阀(6)的外圆周与嵌置该配气阀(6)的罩体(2)的容纳腔的内圆周面之间设有第一密封圈(b1)和第二密封圈(b2),以旋转阀(7)的切换平面(73)与配气阀(6)的配气面(61)的相接触面构成的半径为R3的最小外圆的截面面积为A3；第二密封圈(b2)围绕配气阀(6)所形成的半径为R2的第二密封圈围绕圆的截面面积为A2；R3和R2之间满足以下关系：0.7≤(R2/R3)≤0.95。本发明通过扩大配气阀的配气面与旋转阀的切换平面的相接触面积,以缩小配气阀的正向受压面积,降低了阀门的磨损,该阀门机构加工简单、具有较低的泄漏。(The invention discloses a valve mechanism, which comprises a valve mechanism consisting of a rotary valve (7) and a valve (6), wherein a first sealing ring (b 1) and a second sealing ring (b 2) are arranged between the outer circumference of the valve (6) and the inner circumferential surface of an accommodating cavity of a cover body (2) embedded with the valve (6), and the cross-sectional area of the minimum excircle with the radius of R3, which is formed by the contact surface of a switching plane (73) of the rotary valve (7) and a valve distributing surface (61) of the valve (6), is A3; the cross-sectional area of a circle surrounded by the second sealing ring (b 2) which surrounds the gas distribution valve (6) and has the radius of R2 is A2; the following relationship is satisfied between R3 and R2: 0.7-0.95 (R2/R3). The invention reduces the positive pressure area of the air distribution valve by enlarging the contact area of the air distribution surface of the air distribution valve and the switching plane of the rotary valve, reduces the abrasion of the valve, and has simple processing and lower leakage of the valve mechanism.)

1. A valve mechanism comprises a rotary valve (7) and a valve (6), wherein a first sealing ring (b 1) and a second sealing ring (b 2) are arranged between the outer circumference of the valve (6) and the inner circumferential surface of an accommodating cavity of a cover body (2) embedded with the valve (6), and the valve mechanism is characterized in that: the cross-sectional area of the smallest excircle with the radius of R3 formed by the contact surface of the switching plane (73) of the rotary valve (7) and the gas distribution surface (61) of the gas distribution valve (6) is A3; the cross-sectional area of a circle surrounded by the second sealing ring (b 2) which surrounds the gas distribution valve (6) and has the radius of R2 is A2; the following relationship is satisfied between R3 and R2: 0.7-0.95 (R2/R3).

2. The valve-gate mechanism of claim 1, wherein: the cross-sectional area of a circle surrounded by the first sealing ring (b 1) which surrounds the gas distribution valve (6) and has the radius of R1 is A1, and the following relation is satisfied between R1 and R2: (R1/R2) is less than or equal to 1.

3. A valve train according to claim 1 or 2, wherein: the first sealing ring (b 1) is positioned between the distributing valve (6) and the accommodating cavity of the cover body (2) and separates a high-pressure area (23) and a variable-pressure area (25) between the cover body (2) and the distributing valve (6) in a sealing mode; the second sealing ring (b 2) is located between the distributing valve (6) and the accommodating cavity of the cover body (2) and isolates the low-pressure area (24) and the variable-pressure area (25) between the cover body (2) and the distributing valve (6) in a sealing mode.

4. A valve train according to claim 1 or 2, wherein: the gas distribution surface (61) side of the gas distribution valve (6) is an annular step valve body, the gas distribution valve (6) in the areas of the first sealing ring (b 1) and the second sealing ring (b 2) is a cylindrical valve body, and the annular step valve body which is integrally positioned in the low-pressure area (24) of the cover body (2) is positioned between the second sealing ring (b 2) and the rotary valve (7).

5. A valve train according to claim 1 or 2, wherein: the valve body of the gas distribution valve (6) is in a three-stage step shape, wherein the diameter of a first-stage valve body of the gas distribution valve (6) where a first sealing ring (b 1) is located is smaller than that of a second-stage valve body of the gas distribution valve (6) where a second sealing ring (b 2) is located, and the diameter of a second-stage valve body of the gas distribution valve (6) where a second sealing ring (b 2) is located is smaller than that of a third-stage valve body of the gas distribution surface (61) area of the gas distribution valve (6), and the whole third-stage valve body is located in the low-pressure area (24) of the cover body (2) and located between the second sealing ring (b 2) and the rotary valve (7).

6. A valve train according to claim 1 or 2, wherein: the gas distribution surface (61) side of the gas distribution valve (6) is a frustum-shaped valve body, the gas distribution valve (6) in the areas of the first sealing ring (b 1) and the second sealing ring (b 2) is a cylindrical valve body, and the frustum-shaped valve body which is integrally positioned in the low-pressure area (24) of the cover body (2) is positioned between the second sealing ring (b 2) and the rotary valve (7).

7. A valve train according to claim 1 or 2, wherein: the valve body of the gas distribution valve (6) is in a cone frustum shape, wherein the diameter of the valve body of the gas distribution valve (6) where the first sealing ring (b 1) is located is smaller than that of the valve body of the gas distribution valve (6) where the second sealing ring (b 2) is located, the diameter of the valve body of the gas distribution valve (6) where the second sealing ring (b 2) is located is smaller than that of the valve body of the gas distribution surface (61) area of the gas distribution valve (6), and the whole valve body of the gas distribution surface (61) area of the gas distribution valve (6) is located in the low-pressure area (24) of the cover body (2) and is located between the second sealing ring (b 2) and the rotary valve (7).

8. The valve-gate mechanism of claim 1, wherein: the minimum folding distance L2 of the air distribution valve air hole (63) of the air distribution valve (6) is less than the minimum distance L1 of the high pressure groove of the minimum excircle circumference formed by the contact surface of the switching plane (73) and the air distribution surface (61) from the high pressure groove (72) of the rotary valve (7).

9. A cryogenic refrigerator, characterized by: the cryocooler comprising a valve mechanism according to any one of claims 1 to 8.

10. The cryocooler of claim 9, wherein: the low-temperature refrigerator is a single-machine refrigerator or a multi-stage refrigerator.

Technical Field

The invention belongs to the technical field of low-temperature refrigerators, and particularly relates to a valve mechanism and a low-temperature refrigerator adopting the valve mechanism.

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). The refrigerator provides high pressure air flow from the compressor, and the high pressure air flow enters the pushing piston arranged in the cylinder via the air distributing mechanism and reciprocates up and down to exchange heat with the cold accumulating material, then the high pressure air flow enters the expansion cavity to do work expansion, and then the high pressure air flow flows out of the air distributing mechanism via the pushing piston and returns to the low pressure cavity of the compressor. Through the continuous circulation process, the refrigeration effect is formed.

Specifically, the refrigerator shown in fig. 1 includes a compressor 1, a cover 2, a cylinder 13, and a pushing piston 10, wherein a motor 12 and a driving cam 3 are installed in the cover 2; the eccentric cam handle 31 on the cam 3 drives the connecting rod 5 to convert the rotating motion into the up-and-down reciprocating motion, and the connecting rod 5 is fixed by the guide sleeve 4 in the radial direction, so that the pushing piston 10 is driven to move in the cylinder 13 along the extending direction of the cylinder. The air distribution mechanism RV consists of an air distribution valve 6 and a rotary valve 7. The gas distribution valve 6 is installed in the housing 2 and fixed therein by a positioning pin 16, and the high-pressure gas hole 62 is in gas-tight communication with the high-pressure discharge pipe 1a of the compressor 1 to form a high-pressure region 23 on one side. The other side gas distribution surface 63 is tightly attached to the switching plane 73 of the coaxially arranged rotary valve 7 by means of a pressure difference. The cam shank 31 rotates the rotary valve 7 mounted on the bearing 14 along the rotation axis. The compressor 1 sucks and compresses a refrigerant gas to discharge the refrigerant gas as a high-pressure refrigerant gas. The high-pressure discharge pipe 1a supplies the high-pressure refrigerant gas to the cover 2, and passes through the high-pressure gas hole 62 in the gas distribution valve 6 to the high-pressure groove 72 in the rotary valve 7 to which the gas is hermetically attached. The rotary valve 7 has a low-pressure hole 71 formed therethrough, and the low-pressure hole 71 communicates with the low-pressure passage 22 in the cover 2. According to the position shown in fig. 1, the low-pressure hole 71 is in overlapped communication with the air distribution valve air hole 63 on the air distribution valve 6; at the moment, the system is in a low-pressure exhaust stage, gas in the expansion cavity 9 changes from high pressure to low pressure, and flows out through a piston rear hole 10b, a cold accumulation material 10c and a piston front hole 10a on the pushing piston 10 in sequence and returns to a low-pressure 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 communicated with the air distribution valve air hole 63 on the air distribution valve 6, and the high pressure air 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 sequentially enters the expansion chamber 9 through the piston front hole 10a on the push piston 10, the cold storage material 10c and the piston rear hole 10 b. In the above process, the high-pressure air discharged from the compressor 1 acts on the back surface of the air distribution valve 6, and the air distribution valve 6 is tightly attached to the rotary valve 7 by the positive pressure on the area size parallel to the air distribution surface 61 on the back surface, so that the high-pressure valve and the low-pressure valve on the air distribution mechanism are separated to isolate high-pressure air flow and low-pressure air flow.

The gas distribution valve 6 in the conventional structure is cylindrical (shown in fig. 2 and 3), the cross-sectional area of the minimum outer circle with the radius R3 formed by the contact surface of the switching plane 73 of the rotary valve 7 and the gas distribution surface 61 of the gas distribution valve 6 is A3, and the minimum distance L1 from the gas distribution valve gas hole 63 on the gas distribution surface 61 to the gas distribution hole on the minimum outer circle circumference is the same as the minimum distance L1 (the same symbol is used herein) from the high pressure groove 72 of the rotary valve 7 on the switching plane 73 to the high pressure groove on the minimum outer circle circumference. To prevent leakage of the gas flow, L1 should not be too small to provide a long flow resistance distance to prevent leakage of the high pressure gas flow in high pressure groove 72 into low pressure region 24, which acts as a valve leakage inhibitor. Meanwhile, the high-pressure air hole 62 and the air hole 63 on the air distribution valve 6 have certain size and position requirements, so that the outer diameter of the air distribution valve 6 cannot be too small, otherwise, the valve cannot be manufactured. Therefore, the positive pressure which is attached together is large, the abrasion of the contact surface of the rotary valve 7 and the gas distribution valve 6 can be caused by long-term operation, the performance of the equipment is influenced, and the reliability of the equipment is reduced.

In document 1(CN 104165474B), the minimum distance from the high-pressure groove 72 on the rotary valve 7 to the circumference of the minimum outer circle of the contact surface of the distribution valve 6 and the rotary valve 7 is greater than the minimum distance from the distribution valve air hole 63 on the distribution valve 6 to the circumference of the minimum outer circle of the contact surface of the distribution valve 6 and the rotary valve 7, and this plays a certain role in suppressing leakage. However, this configuration does not allow the high pressure groove 72 to completely cover the gas port 63, and introduces additional flow resistance losses for higher flow valves.

In document 2(CN 107449171 a), the gas distribution valve 6 is in a three-step ladder shape, and an additional third sealing member is mounted on the circumferential surface of the smallest outer circle of the contact surface of the gas distribution valve 6 and the rotary valve 7, so that when the gas distribution valve is communicated with the high-pressure gas path, a positive high-pressure is formed on the surface, and leakage is suppressed. However, in order to reduce the wear of the valve and reduce the positive pressure formed by the minimum circumference formed by the third sealing element, an additional low-pressure constant-pressure area must be introduced between the first sealing element and the second sealing element, and an air guide duct needs to be machined on the component, so that the machining difficulty and the cost are increased. Meanwhile, the pressure in the constant-pressure area is low pressure, and the areas with isolated sealing at two sides are high-pressure areas, so that the risk of air leakage of high pressure and low pressure is increased.

Disclosure of Invention

The present invention has been made in view of the above problems occurring in the prior art, and an object of the present invention is to provide a valve mechanism and a cryocooler using the same, which can suppress leakage of a valve by modifying the structure of the valve mechanism.

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

the utility model provides a valve mechanism, includes the valve timing mechanism that rotary valve and distribution valve constitute, is equipped with first sealing washer and second sealing washer between the outer circumference of this distribution valve and the inner circumferential surface of the chamber that holds of the cover body of embedding this distribution valve, its characterized in that: the section area of the minimum excircle with the radius of R3 formed by the contact surface of the switching plane of the rotary valve and the gas distribution surface of the gas distribution valve is A3; the cross-sectional area of a circle surrounded by the second sealing ring with the radius of R2 formed by the second sealing ring surrounding the gas distribution valve is A2; the following relationship is satisfied between R3 and R2: 0.7-0.95 (R2/R3).

The cross-sectional area of a circle surrounded by the first sealing ring with the radius R1 formed by the first sealing ring surrounding the gas distribution valve is A1, and the following relation is satisfied between R1 and R2: (R1/R2) is less than or equal to 1.

The first sealing ring is positioned between the gas distribution valve and the accommodating cavity of the cover body and isolates a high-pressure area and a variable-pressure area between the cover body and the gas distribution valve in a sealing mode; the second sealing ring is positioned between the gas distribution valve and the accommodating cavity of the cover body and isolates a low-pressure area and a variable-pressure area between the cover body and the gas distribution valve in a sealing mode.

The gas distribution surface side of the gas distribution valve is an annular step valve body, the gas distribution valve in the areas of the first sealing ring and the second sealing ring is a cylindrical valve body, and the annular step valve body which is integrally positioned in the low-pressure area of the cover body is positioned between the second sealing ring and the rotary valve.

The valve body of the gas distribution valve is in a three-stage step shape, wherein the diameter of a first-stage valve body of the gas distribution valve where the first sealing ring is located is smaller than the diameter of a second-stage valve body of the gas distribution valve where the second sealing ring is located, the diameter of the second-stage valve body of the gas distribution valve where the second sealing ring is located is smaller than the diameter of a third-stage valve body of a gas distribution surface area of the gas distribution valve, and the whole third-stage valve body is located in a low-pressure area of the cover body and located between the second sealing ring.

The gas distribution surface side of the gas distribution valve is a frustum-shaped valve body, the gas distribution valve in the areas of the first sealing ring and the second sealing ring is a cylindrical valve body, and the frustum-shaped valve body which is integrally positioned in the low-pressure area of the cover body is positioned between the second sealing ring and the rotary valve.

The valve body of the gas distribution valve is in a cone frustum shape, wherein the diameter of the valve body of the gas distribution valve where the first sealing ring is located is smaller than that of the valve body of the gas distribution valve where the second sealing ring is located, the diameter of the valve body of the gas distribution valve where the second sealing ring is located is smaller than that of the gas distribution surface area of the gas distribution valve, and the whole body of the valve body of the gas distribution surface area of the gas distribution valve is located in the low-pressure area of the cover body and located between the second sealing ring and the rotary valve.

The minimum folding distance L2 of the air distribution valve air hole of the air distribution valve is less than the minimum distance L1 from the high pressure groove of the rotary valve to the high pressure groove of the minimum excircle circumference formed by the contact surface of the switching plane and the air distribution surface.

A cryogenic refrigerator, characterized by: the cryocooler comprises the valve mechanism described above.

The low-temperature refrigerator is a single-machine refrigerator or a multi-stage refrigerator.

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

the valve mechanism of the invention reduces the positive pressure area of the air distribution valve by enlarging the contact area of the air distribution surface of the air distribution valve and the switching plane of the rotary valve, reduces the abrasion of the valve, and has simple processing and lower leakage.

Drawings

FIG. 1 is a schematic diagram of a cryocooler with a conventional valve mechanism;

FIG. 2 is a schematic diagram of a conventional valve mechanism;

FIG. 3 is a three-dimensional schematic view of a conventional valve mechanism;

FIG. 4 is a schematic structural view of a valve mechanism provided in accordance with the present invention;

FIG. 5 is a second schematic structural view of a valve mechanism provided in the present invention;

FIG. 6 is a third schematic structural view of a valve mechanism provided in the present invention;

FIG. 7 is a fourth schematic view of the valve mechanism according to 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-high pressure zone; 24-a low-pressure region; 25-a pressure change zone; 3, a cam; 31-eccentric cam handle; 4, a guide sleeve; 5, connecting rods; 6-distributing valve; 61-air distribution surface; 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; 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-a positioning pin; b1 — first seal ring; b 2-second sealing ring.

Detailed Description

In connection with the background of the art, a detailed description of conventional valve structures and cryocooler structures will not be repeated. The invention is further described with reference to the following figures and examples.

As shown in fig. 4, 5, 6, and 7: a valve mechanism comprises an air distribution valve 6 and a rotary valve 7, wherein the air distribution valve 6 is provided with a high-pressure air hole 62 which axially penetrates through the air distribution valve 6 and an air distribution valve air hole 63 which axially penetrates through the air distribution valve 6, the folding direction of the air distribution valve air hole 63 is the minimum distance L2, the high-pressure air hole 62 can be communicated with a high-pressure exhaust pipeline 1a of a compressor 1, and the air distribution valve air hole 63 can be communicated with a cover body air hole 21 on a cover body 2; meanwhile, the high-pressure air hole 62 can be communicated with the air distribution valve air hole 63 and the cover body air hole 21 through a high-pressure groove 72 on the rotary valve 7; alternatively, the air vent 63 communicates with the low pressure passage 22 of the cover body 2 through a low pressure hole 71 penetrating the rotary valve 7. The circumferential surface of the gas distribution valve 6 is provided with a first sealing ring b1 and a second sealing ring b2 which are embedded on the inner wall of the installation cavity of the cover body 2, the gas distribution valve 6 is sealed, the gas distribution valve air hole 63 on the gas distribution valve 6 is connected with the cover body air hole 21 on the cover body 2 in a sealing way and is not communicated with the gas at other positions, and the gas distribution valve air hole 63 on the gas distribution valve 6 is the only passage of the high-pressure gas and the low-pressure gas which enter or flow out of the cylinder 13. The back surface of the gas distributing valve 6 and the cover body 2 form a high pressure area 23, and the high pressure area 23 can be in air-tight communication with the high pressure air hole 62 and the high pressure groove 72. The periphery of the gas distribution surface 63 is contained within the low pressure region 24. In the above structure, the switching plane 73 of the rotary valve 7 is tightly attached to the valve actuating surface 61 of the rotary valve 6 by the high-pressure air flow in the high-pressure region 23 and the spring 15.

The following specifically describes embodiments of the present invention.

Fig. 4 shows a first embodiment of the valve mechanism provided in the present invention.

The cross-sectional area of a circle surrounded by a second sealing ring b2 with the radius R2 formed around the gas distribution valve 6 is A2, and the second sealing ring b2 hermetically separates the cover body 2 from the pressure change area 25 and the low pressure area 24 at the gas distribution valve 6; the cross-sectional area of a circle surrounded by the first sealing ring b1 with the radius R1 formed around the gas distribution valve 6 is A1, and the first sealing ring b1 hermetically separates the cover body 2 from the pressure changing area 25 and the high pressure area 23 on the gas distribution valve 6. In the central axial direction, the minimum folding distance L2 arranged on the air distributing valve air hole 63 in the pressure changing area 25 is not necessary distance for inhibiting the valve leakage, so in the implementation process, only the switching plane 73 of the rotary valve 7 is in contact with the air distributing surface 61 of the air distributing valve 6, the size of the cross-sectional area A3 of the minimum excircle with the radius R3 formed by the contact surface is kept large, namely the minimum distance L1 of the high pressure groove in the technical background is kept in proper size; the R2 or the R2 and the R1 are reduced and the folding direction is the minimum distance L2, so that the gas distributing valve 6 forms a two-stage step shape, and R2/R3 is less than 1, and R1/R2 is equal to 1. Thus, the positive pressure-receiving area acting on the gas distribution valve 6 is changed from A3 to original A2, so that projected circular rings (R3-R2) in the axial direction of the central shaft are accommodated in the low-pressure area 24, and the abrasion of the valve is reduced on the basis of keeping the minimum distance L1 of the high-pressure groove with the necessary length.

The infinitesimal area which takes the central axial direction of the gas distribution valve 6 as an original point and takes a certain distance from the original point on the gas distribution surface 63 as R is characterized as follows: rd θ · dR. The wear loss q of the infinitesimal area per unit time is: q ═ K · (Δ P · a2/A3) · (R · ω) · (Rd θ · dR), where: k is the wear rate of the distributing valve 6 relative to the rotary valve 7; (Δ P. A2/A3) is the positive pressure of the contact surface; r & omega is the linear velocity on the area of the infinitesimal; omega is angular frequency; d is a differential sign; theta is an angle.

The formula of the abrasion loss q is simplified to obtain: q ═ K.DELTA.P.ω (R2/R3)²·R²D θ dR, wherein the equation is a differential equation of the wear rate of the valve in unit time, and the equation is integrated to obtain an average wear amount Q of the valve in unit time: q2 pi · K · Δ P · ω · (R2/R3)²·(R3)³And/3, wherein Q is the average abrasion loss of the valve per unit time.

When R2 ═ R3, the valve structure reverts to the conventional valve structure. That is, R3 remained unchanged, as R2 shrunk, the amount of wear decreased proportionally as a square index. Table 1 gives the improved structure versus conventional valve data (values have been normalized).

TABLE 1 abrasion loss comparison data sheet for improved structure and conventional valve mechanism

	Size of traditional valve structure	Improved structure 1	Improved structure 2	Improved structure 3
					R3	1	1	1.1	1
R2	1	0.95	0.95	0.7
					R2/R3	1	0.95	0.86	0.7
Amount of wear	1	0.9	0.98	0.49

It is calculated from table 1 that even if the size of R3 is increased in order to suppress valve leakage, the wear of the valve is not increased by adjusting the size of R2, which facilitates the design of the valve. Meanwhile, in consideration of the sizes of the high-pressure hole 62 and the air hole 63 on the air distribution valve 6, R2/R3 is designed to be more than or equal to 0.7 in the practical implementation process.

Fig. 5 is a view showing a structure in which the annular step valve body in fig. 4 is changed to a frustum valve body, that is, fig. 5, based on a modification of the embodiment in fig. 4.

Fig. 6 shows another embodiment of the basic structure of fig. 4. In the embodiment, the size of the radius R1 of the first sealing element surrounding the circle A1 corresponding to the first sealing element b1 is further reduced, so that R1/R2 is less than 1, the distributing valve 6 forms a three-step ladder shape, the variable pressure area 25 is isolated into a ladder structure by the first sealing element b1 and the second sealing element b2, in a half period, the high pressure groove 72 is communicated with the distributing valve air hole 63, the variable pressure area 25 is high pressure, and the positive pressure area borne by the distributing valve 6 is A2; in the other half period, the low pressure hole 71 is communicated with the air distribution valve air hole 63, the pressure changing area 25 becomes low pressure, and the positive pressure area of the air distribution valve 6 is A1. The average wear per unit time of the valve in such a cycle is mathematically transformed into: q ═ pi · K · Δ P · ω · [ (R2+ R1)/R3]²·(R3)³/12. This can further reduce the amount of wear per unit time of the valve while suppressing leakage of the valve.

For simplicity of processing, fig. 7 shows another embodiment. The housing 2 contains a cavity for receiving the gas distribution valve 6 and the gas distribution valve 6 is shaped like a truncated cone, and the surface close to the high pressure area 23 is smaller than the gas distribution surface 61 of the gas distribution valve 6. In implementation, the cross-sectional area A3 of the smallest outer circle of the contact surface of the gas distribution valve 6 and the rotary valve 7 is the largest area of the truncated cone in the axial cross section, so when the first sealing ring b1 and the second sealing ring b2 are sealed on the outer circumference of the gas distribution valve 6, the cross-sectional area of the first sealing ring surrounding the circle is a1, and the cross-sectional area of the second sealing ring surrounding the circle is a2, the following conditions are met: a1< a2< A3, i.e.: r1< R2< R3. By adjusting the proper taper, the three radiuses reach proper proportions, so that the valve mechanism does not increase the abrasion of the valve mechanism while inhibiting leakage.

A cryocooler comprises the valve mechanism. The low-temperature refrigerator is a valve switching type refrigerator in any form, is not limited to a gifford-mcmahon refrigerator, a solvin refrigerator, a pulse tube refrigerator and the like, and can be applied to a single-stage or double-stage refrigerator.

The invention can effectively inhibit the leakage of the valve by adjusting the appearance structure of the gas distribution valve 6 on the basis of not increasing the abrasion of the valve.

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.