A rotary valve with pre-tightening force and a low-temperature refrigerator using the rotary valve

Abstract

The present invention discloses a rotary valve with preload, characterized in that: the rotary valve (7) is composed of a rotary valve seat (7a) and a rotary valve body (7b) installed in a receiving cavity (7a2) of the rotary valve seat (7a); a passage that can penetrate the rotary valve seat (7a) and the rotary valve body (7b) is provided as a low-pressure hole (71); a valve body high-pressure groove (7b2) is provided on the switching plane (73) side of the rotary valve body (7b); a force applying mechanism that can apply positive pressure to the valve body bottom surface (7b3) at the far end of the valve body high-pressure groove (7b2) away from the low-pressure hole (71); the positive pressure applied by the force applying mechanism can offset the eccentric force generated by the positive pressure of the high-pressure groove (7b2) on the high-pressure groove (7b2) of the valve body. The rotary valve of the present invention always provides an eccentric preload through the force applying mechanism, thereby reducing the influence of "asymmetric pressure" in the whole cycle.

Description

Technical Field

[0001] The invention belongs to the technical field of low-temperature refrigerators, in particular to a rotary valve with pre-tightening force and a low-temperature refrigerator using the rotary valve. Background Art

[0002] A cryogenic refrigerator represented by a Gifford-McMahon (GM) refrigerator includes an expander and a compressor of a working gas (also called a refrigerant gas). Figure 1 This is a refrigerator of this type. The high-pressure airflow discharged by the compressor 1 enters the push piston 10 placed in the cylinder 13 and reciprocating up and down through the valve mechanism RV (valve 6 and rotary valve 7), exchanges heat with the cold storage material 10c, and then expands in the expansion chamber 9 to do work, and then flows out of the valve mechanism through the push piston 10 and returns to the low-pressure chamber of the compressor 1. Through the above continuous cycle process, a refrigeration effect is formed.

[0003] The plane rotary valve includes two main parts: the rotary valve 7 and the gas distribution valve 6, one of which is made of resin wear-resistant material and the other is made of metal material. When working, the two parts fit together, and the connection state of the grooves on the rotary valve 7 and the gas distribution valve 6 is switched by the rotation of the rotary valve 7 to achieve the switching of high and low pressure airflow. The fitting process is compressed by the pressure difference on both sides of the gas distribution mechanism. Then, for the GM refrigerator, the gas distribution mechanism (RV) is as follows Figure 2 As shown, the high-pressure groove 72 and the low-pressure hole 71 on the rotary valve 7 are respectively connected to the high-pressure airflow and the low-pressure airflow in an airtight manner, and are arranged eccentrically on both sides of the rotary axis O (dashed line) of the rotary valve 7 itself. The pressure between the switching surface 73 and the gas distribution valve surface 61 in one cycle is "asymmetric pressure", that is, the pressure on both sides symmetrical to the rotary axis O is different. Therefore, this type of valve is called an asymmetric plane rotary valve.

[0004] The high-pressure gas discharged from the compressor 1 acts on the back side of the gas distribution valve face 61 relative to the gas distribution valve 6. The gas distribution valve 6 relies on the positive pressure on the back side and the elastic force of the spring 15 to fit tightly with the rotary valve 7 to form an airtight sliding contact surface to ensure that the switching surface 73 of the asymmetric rotary valve 7 and the gas distribution valve face 61 of the gas distribution valve 6 will not be pushed open by the air pressure (the area on the sliding surface where the pressure from both sides is applied is called the double-side action area). However, a large number of actual operation cases reflect that in the structure where the working high-pressure gas and the spring 15 press the back side of the gas distribution valve 6 (relative to the gas distribution valve face 61) symmetrically relative to the central axis, the above-mentioned "asymmetric pressure" generates torque on the double-side action area, which will make the double-side action area close to the high-pressure groove 72 of the rotary valve 7 more likely to separate, and there is a risk of refrigerant gas leakage.

[0005] Specifically, Figure 3 Take the example shown. The rotary valve 7 is installed in the bearing 14, and its own rotation axis O is coaxially positively pressed on the gas distribution valve 6. The high-pressure groove 72 on the rotary valve 7 extends from the center position of the rotation axis O, and is slotted along the side away from the central axis O, and is connected to the opening on the central axis of the gas distribution valve 6-the high-pressure air hole 62, and the pressure of the high-pressure working gas is applied to each end and groove of the high-pressure air hole 62. The gas distribution valve 6 is processed with a gas distribution valve air hole 63 in the direction closer to the cover body air hole with the rotation axis O as the center. Since the high-pressure groove 72 and the low-pressure hole 71 on the rotary valve 7 are distributed on both sides of the rotation axis O, when the rotary valve 7 rotates about the O axis, the high-pressure groove 72, the low-pressure hole 71 and the gas distribution valve air hole 63 on the rotary valve 6 will overlap and separate periodically. In this way, the high-pressure and low-pressure valve switching of the refrigerant airflow is achieved.

[0006] by Figure 3 For example, the high-pressure groove 72 on the rotary valve 7 is bounded by the central axis O, and two areas X1 and X2 are divided at the bottom of the groove, and a positive pressure Ph (high pressure) is applied, and X1>X2. Therefore, the positive pressure acting on the X1 area is greater than the positive pressure acting on the X1 area, forming an eccentric force close to the extension direction of the high-pressure groove 72. At the same time, the air distribution valve 6 is also subjected to the eccentric force of the positive pressure Ph in the area X3 opposite to the high-pressure groove 72, and the direction is closer to the extension direction of the high-pressure groove 72 relative to the central axis O. The above two force effects are to form an outward separation effect between the air distribution valve 6 and the rotary valve 7 in the direction close to the extension side of the high-pressure groove 72 with the rotation axis O as the center. In the theoretical design, the rotary valve 7 and the air distribution valve 6 are respectively fixed in the bearing 14 and the cover body 2 in the radial direction perpendicular to the rotation axis O. During operation, there is no separation of the rotary valve 7 or the air distribution valve 6 around the rotation axis O. However, in the actual process, for the convenience of installation, during the implementation, there are radial clearances between the bearing 14 and the rotary valve 7, between the bearing 14 and the cover 2, and between the valve 6 and the cover 2. In addition, the bearing 14 itself also has "radial clearance" and "axial clearance". The existence of these clearances makes the switching plane 73 and the valve face 61 have a "retreat" space under the action of positive pressure during the operation of the valve mechanism (RV), that is, the following is formed: Figure 3 As shown: the central axis of the rotary valve 7 and the gas distribution valve 6 form angles A1 and A2 with the design central axis O respectively, extending in one direction close to the high-pressure groove 72 to form an opening angle, which always exists.

[0007] Document 1 (CN 103968591) proposes an improved idea, which is to eccentrically install a spring 15 on the side of the gas distribution valve hole 63 on the gas distribution valve 6 so that the center of the spring's pressing force is closer to the gas flow path. This technology is mainly aimed at the time period (regional section) when the leakage possibility is the greatest in the action area of ​​both parties, but in the remaining time period, "asymmetric pressure" still exists, that is, the leakage problem still exists.

[0008] Document 2 (CN 107449171) improves the structure of the gas distribution valve 6. When the high-pressure intake is connected to the gas distribution valve hole 63, the active areas of both sides are subjected to a large positive pressure. However, when the low-pressure exhaust process is connected to the gas distribution valve hole 63, the positive pressure of the active areas of both sides will become smaller, and the "asymmetric pressure" still exists, so the risk of leakage still exists. Summary of the invention

[0009] The purpose of the present invention is to provide a rotary valve with pre-tightening force and a low-temperature refrigerator using the rotary valve in order to solve the problems existing in the prior art; the low-temperature refrigerator switches the flow path through the rotation of the rotary valve and the gas distribution valve and can suppress gas leakage between valves to ensure the stability of the equipment.

[0010] The purpose of the present invention is to be solved by the following technical solutions:

[0011] A rotary valve with a preload force, characterized in that: the rotary valve consists of a rotary valve seat and a rotary valve body installed in a accommodating cavity of the rotary valve seat, and the rotary valve seat and the rotary valve body are fixedly connected, and a channel that can penetrate the two is provided on the rotary valve seat and the rotary valve body as a low-pressure hole, a valve body high-pressure groove is opened on the switching plane side of the rotary valve body, and a force-applying mechanism that can apply positive pressure to the bottom surface of the valve body at the far end of the valve body high-pressure groove is provided at the far end of the valve body high-pressure groove away from the low-pressure hole, and there is no airflow flow characteristic between the area where the above-mentioned pressure-applying mechanism is located and the low-pressure hole; the positive pressure applied by the force-applying mechanism to the bottom surface of the valve body at the far end of the valve body high-pressure groove can offset the eccentric force generated by the high-pressure airflow on the positive pressure of the high-pressure groove.

[0012] The valve body high-pressure groove is provided with a channel that penetrates the rotary valve body and is located at the far end of the valve body high-pressure groove away from the low-pressure hole. The circumferential outer side of the channel is provided with a seal embedded in the bottom surface of the valve body and / or the bottom surface of the accommodating cavity of the accommodating cavity. The pressure area surrounded by the above-mentioned seal and the bottom surface of the valve body and the bottom surface of the accommodating cavity is connected to the valve body high-pressure groove through the channel to introduce high-pressure airflow to form a force-applying mechanism.

[0013] A blind hole is provided on the bottom surface of the valve body and / or the bottom surface of the accommodating cavity, and the blind hole is located on the distal side of the high-pressure groove of the valve body away from the low-pressure hole; an elastic element capable of protruding out of the blind hole is provided in the blind hole, and the blind hole and the elastic element can constitute a force-applying mechanism for applying positive pressure to the bottom surface of the valve body at the distal end of the high-pressure groove of the valve body.

[0014] The elastic element is a spring, a spring washer, a rubber pad or a rubber ring that can provide a restoring force after being compressed.

[0015] The rotary valve seat is provided with a valve seat low-pressure hole which can penetrate the rotary valve seat, and the rotary valve body is provided with a valve body low-pressure hole which can penetrate the rotary valve body. The valve seat low-pressure hole and the valve body low-pressure hole constitute the low-pressure hole of the rotary valve.

[0016] The rotary valve seat and the rotary valve body are fixedly connected via a rotary valve positioning pin to limit relative rotation therebetween.

[0017] A valve seat positioning pin hole into which a rotary valve positioning pin can be inserted is provided on the bottom surface of the accommodating cavity, and a valve body positioning pin hole into which a rotary valve positioning pin can be inserted is provided on the bottom surface of the valve body.

[0018] The valve seat locating pin hole and the valve body locating pin hole are arranged adjacent to the low-pressure hole.

[0019] The rotary valve seat is rotatably supported in the cover body by a bearing.

[0020] A low-temperature refrigerator comprises a gas distribution mechanism, which is composed of a gas distribution valve and the above-mentioned rotary valve combination.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] The rotary valve of the present invention, through the setting of the force-applying mechanism, always has an eccentric pre-tightening force on the far-end switching surface of the high-pressure groove of the valve body away from the low-pressure hole of the rotary valve (that is, the double-acting pressure area where separation and gas leakage are prone to occur), thereby reducing the influence of the "asymmetric pressure" throughout the whole cycle and reducing the risk of refrigerant gas leakage in the pressure area. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG1 is a schematic diagram showing the structure of a low-temperature refrigerator in the present invention;

[0024] Figure 2 is a schematic diagram of the three-dimensional structure of a conventional rotary valve mechanism;

[0025] Figure 3 is a schematic diagram of the leakage plane structure of a conventional rotary valve mechanism;

[0026] FIG4 is a schematic diagram of the explosion structure of the rotary valve with pre-tightening force provided by the present invention;

[0027] FIG5 is a schematic diagram of the installation structure of the rotary valve with pre-tightening force provided by the present invention;

[0028] FIG. 6 is a schematic diagram of another embodiment of the rotary valve with pre-tightening force provided by the present invention.

[0029] Among them: 1-compressor; 1a-high-pressure exhaust pipe; 1b-low-pressure suction pipe; 2-cover; 21-cover air hole; 22-low-pressure passage; 3-cam; 31-eccentric cam handle; 4-guide sleeve; 5-connecting rod; 6-gas distribution valve; 61-gas distribution valve surface; 62-high-pressure air hole; 63-gas distribution valve air hole; 7-rotary valve; 71-low-pressure hole; 72-high-pressure groove; 73-switching plane; 74-jack; 75-back; 7a-rotary valve seat; 7a1-valve seat low-pressure hole; 7a2-accommodating chamber; 7a3-accommodating chamber bottom surface; 7a4- Valve seat locating pin hole; 7b—rotary valve body; 7b1—valve body low-pressure hole; 7b2—valve body high-pressure groove; 7b3—valve body bottom surface; 7b4—valve body locating pin hole; 7b5—channel; 8—hot chamber; 9—expansion chamber; 10—push piston; 10a—piston front hole; 10b—piston rear hole; 10c—cold storage material; 12—motor; 13—cylinder; 14—bearing; 15—spring; 16—gas distribution valve locating pin; 100—elastic element; 101—seal; 102—blind hole; 103—rotary valve locating pin; S1—pressure application area. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0031] like Figure 1 As shown, this type of low-temperature refrigerator includes a compressor 1, a housing 2, a cylinder 13, and a push piston 10. The housing 2 is equipped with a motor 12 and a driven cam 3; the eccentric cam handle 31 on the cam 3 drives the connecting rod 5 to convert the rotary motion into up and down reciprocating motion, thereby driving the push piston 10 to move up and down in the cylinder 13. The valve mechanism RV is composed of a valve 6 and a rotary valve 7. The valve 6 is installed in the housing 2, fixed therein by the valve positioning pin 16, and arranged coaxially with the rotary valve 7. The cam handle 31 drives the rotary valve 7 installed on the bearing 14 to rotate along the rotating shaft. The compressor 1 inhales and compresses the refrigerant gas and discharges it as high-pressure refrigerant gas. The high-pressure exhaust pipe 1a supplies the high-pressure refrigerant gas to the housing 2, and transmits it to the high-pressure groove 72 on the rotary valve 7 that is airtightly fitted therewith through the high-pressure gas hole 62 on the central axis of the valve 6, and the high-pressure groove 72 is not connected to the low-pressure hole 71. The rotary valve 7 has a low-pressure hole 71 in communication with the low-pressure passage 22 in the housing 2. The high-pressure groove 72 extends radially outward along the rotary axis O and is eccentrically arranged on the rotary valve 7. The low-pressure hole 71 is arranged on the other side of the axis O opposite to the high-pressure groove 72.

[0032] According to the position shown in Figure 1, the low-pressure hole 71 is overlapped and connected with the gas distribution valve hole 63 on the gas distribution valve 6; at this moment, the low-pressure hole 71 on the rotary valve 7, the gas distribution valve hole 63 on the gas distribution valve 6 and the cover body hole 21 on the cover body 2 are connected, and the system is in the low-pressure exhaust stage. The gas in the expansion chamber 9 changes 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 intake pipe 1b of the compressor 1. When the rotary valve 7 rotates to a certain angle, the low-pressure hole 71 is no longer connected to the gas distribution valve hole 63 on the gas distribution valve 6, and the high-pressure groove 72 on the rotary valve 7 is connected to the gas distribution valve hole 63 on the gas distribution valve 6 (the matching relationship is not shown). At this moment, the high-pressure gas discharged from the compressor 1 enters the cylinder 13 through the high-pressure gas hole 62 on the gas distribution valve 6 and the high-pressure groove 72 on the rotary valve 7 connected thereto, and enters the expansion chamber 9 through the piston front hole 10a, the cold storage material 10c, and the piston rear hole 10b on the push piston in sequence. In the above process, the high-pressure gas discharged from the compressor 1 acts on the back of the gas distribution valve 6, and the gas distribution valve 6 relies on the positive pressure on the back and the elastic force of the spring 15 to tightly fit with the rotary valve 7 to form an airtight sliding contact surface. Both the rotary valve 7 and the air distribution valve 6 are designed as a rotating body structure along the rotation axis, wherein the rotary valve 7 is rotatably supported by the bearing 14 in the cover body 2; the air distribution valve 6 is coaxially arranged with the rotary valve 7 in the cover body 2, and the air distribution valve 6 is fixed by the air distribution valve locating pin 16 so as to be unable to rotate, but can be loaded and unloaded along the axial direction of the center axis O.

[0033] Embodiment 1

[0034] Figure 4 , Figure 5As shown, the rotary valve 7 is of a separate type, consisting of a metal rotary valve seat 7a and a metal rotary valve body 7b installed in its accommodating chamber 7a2, and a valve seat positioning pin hole 7a4 is opened on the bottom surface of the accommodating chamber 7a2 of the rotary valve seat 7a, and a valve body positioning pin hole 7b4 is arranged coaxially with the valve body bottom surface 7b3 of the rotary valve body 7b, and the relative rotation between the two is limited by the rotary valve positioning pin 103, but the rotary valve seat 7a and the rotary valve body 7b can be disassembled along the axial direction. The high-pressure gas hole 62 on the gas distribution valve 6 airtightly connects the high-pressure gas flow discharged from the compressor 1 with the high-pressure groove 72 extending radially outward on the switching surface 73 of the rotary valve body 7b at the center side corresponding to the rotation axis O; the high-pressure groove 7b2 on the switching plane 73 of the rotary valve body 7b extends radially outward along the rotation axis O as the starting point to form a high-pressure gas switching channel. The rotary valve seat 7a and the rotary valve body 7b are processed with through holes that penetrate themselves and are interconnected on the other side of the radial direction relative to the extension direction of the high-pressure groove 7b2 - the valve seat low-pressure hole 7a1 and the valve body low-pressure hole 7b1. The valve seat low-pressure hole 7a1 and the valve body low-pressure hole 7b1 constitute the low-pressure hole 71 which can be air-tightly connected with the low-pressure passage 22 to form a low-pressure gas switching channel.

[0035] A through hole 7b5 is provided on the bottom surface 7b3 of the valve body of the rotary valve main body 7b, which is connected to the high-pressure groove 7b2 of the valve body, so as to introduce the high-pressure gas flow into the pressure area S1 between the bottom surface 7b3 of the accommodating cavity 7a2 of the rotary valve seat 7a and the bottom surface 7b3 of the valve body of the rotary valve main body 7b. Since the periphery of the rotary valve 7 is always in a low-pressure gas atmosphere, in order to prevent the high-pressure gas in the pressure area S1 from flowing to the low-pressure gas, especially the low-pressure pressure area where the valve seat low-pressure hole 7a1 and the valve body low-pressure hole 7b1 are located, a seal 101 is installed on the periphery of the pressure area S1, and the positive pressure from the gas distribution valve 6 is used to press the rotary valve main body 7b against the positive pressure of the rotary valve seat 7a, thereby isolating it from the surrounding low-pressure gas atmosphere, and ensuring that the pressure area S1 has no gas flow characteristics with the surrounding.

[0036] With the rotation axis O as the center, the center position of the pressure application area S1 is located on the extended side of the valve body high pressure groove 7b2 away from the low pressure hole 71, and the pressure application area S1 is always connected with the valve body high pressure groove 7b2, that is, the high pressure gas pressure application area, and positive pressure is applied on the bottom surface 7a3 of the accommodating cavity 7a2, closer to the far end of the valve body high pressure groove 7b2, to press the rotary valve seat 7b "backward" onto the bearing 14; at the same time, the positive pressure applies positive pressure on the valve body bottom surface 7b3 of the rotary valve body 7b, closer to the far end of the high pressure groove 7b2, to press the side of the rotary valve body 7b close to the far end of the valve body high pressure groove 7b2 toward the corresponding side of the gas distribution valve 6. By adjusting the area and position of the pressure application area S1, the eccentric force generated by the positive pressure in the high pressure groove 72 mentioned in the previous technical background can be offset to prevent the switching surface 73 from separating from the gas distribution valve surface 61.

[0037] Embodiment 2

[0038] like Figure 6 As shown, a blind hole 102 can be processed at the pressure application area S1 described in the first embodiment, and an elastic element 100 is installed in the blind hole 102, that is, a blind hole 102 is processed on the bottom surface 7b3 of the valve body or the bottom surface 7a3 of the accommodating groove relative to the rotation axis O, closer to the distal end of the valve body high pressure groove 7b2 away from the low pressure hole 71, and the elastic element 100 is compressed and placed inside the blind hole 102. By adjusting the depth and position of the blind hole 102, the preload force of the rotary valve seat 7a and the rotary valve body 7b close to the distal end of the valve body high pressure groove 7b2 can be properly adjusted to offset the eccentric force generated by the positive pressure in the valve body high pressure groove 7b2. Since the internal air flow of the blind hole 102 processed on the bottom surface 7b3 of the valve body or the bottom surface 7a3 of the accommodating groove is connected to the valve seat low-pressure hole 7a1 or the valve body low-pressure hole 7b1, both are low-pressure pressure areas. Therefore, there is no gas flow between the pressure area S1 of the force-applying mechanism and the valve seat low-pressure hole 7a1 or the valve body low-pressure hole 7b1.

[0039] In the above implementation process, the elastic element 100 mentioned can be a spring, a spring washer, a rubber pad or a rubber ring, etc., which are devices that can provide a large restoring force after being compressed.

[0040] A cryogenic refrigerator using the above rotary valve with preload force comprises the above gas distribution mechanism, wherein the gas distribution valve 6 of the gas distribution mechanism is eccentrically fixed on the cover body 2 through the valve body positioning pin 16; the rotary valve 7 of the gas distribution mechanism is positioned in the cover body 2 through the bearing 14. The cryogenic refrigerator is any type of valve switching refrigerator, not limited to Gifford-McMahon refrigerator, Solvang refrigerator, pulse tube refrigerator, etc.

[0041] The rotary valve of the present invention has a force-applying mechanism so that an eccentric preload force is always applied on the far-end switching surface of the high-pressure groove 7b2 of the valve body of the rotary valve 7 away from the low-pressure hole 7 (i.e., the double-acting pressure area prone to separation and gas leakage), thereby reducing the influence of the "asymmetric pressure" throughout the entire cycle and reducing the risk of refrigerant gas leakage in the pressure area.

[0042] The above embodiments are only for illustrating the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the present invention; any technology not involved in the present invention can be realized by existing technologies.

Claims

1. A rotary valve with preload, characterized in that: The rotary valve (7) comprises a rotary valve seat (7a) and a rotary valve body (7b) installed in a receiving cavity (7a2) of the rotary valve seat (7a), wherein the rotary valve seat (7a) and the rotary valve body (7b) are fixedly connected, and a passage capable of penetrating the two is provided on the rotary valve seat (7a) and the rotary valve body (7b) as a low-pressure hole (71), a valve body high-pressure groove (7b2) is provided on the switching plane (73) side of the rotary valve body (7b), and a force applying mechanism capable of applying positive pressure to a valve body bottom surface (7b3) at the far end of the valve body high-pressure groove (7b2) is provided at the far end of the valve body high-pressure groove (7b2) away from the low-pressure hole (71), wherein the positive pressure applied by the force applying mechanism to the valve body bottom surface (7b3) at the far end of the valve body high-pressure groove (7b2) can offset the eccentric force generated by the high-pressure airflow on the positive pressure of the high-pressure groove (7b2).

2. The rotary valve with preload according to claim 1, characterized in that: The valve body high pressure groove (7b2) is provided with a channel (7b5) which penetrates the rotary valve body (7b) and is located at the far end of the valve body high pressure groove (7b2) away from the low pressure hole (71); the outer circumferential side of the channel (7b5) is provided with a sealing member (101) embedded in the bottom surface (7b3) of the valve body and / or the bottom surface (7a3) of the accommodating cavity (7a2); the pressure application area (S1) surrounded by the sealing member (101) and the bottom surface (7b3) of the valve body and the bottom surface (7a3) of the accommodating cavity is connected to the valve body high pressure groove (7b2) through the channel (7b5) to introduce high pressure airflow to form a force application mechanism.

3. The rotary valve with preload according to claim 1, characterized in that: A blind hole (102) is provided on the bottom surface (7b3) of the valve body and / or on the bottom surface (7a3) of the accommodating cavity (7a2), and the blind hole (102) is located at the distal end side of the high-pressure groove (7b2) of the valve body away from the low-pressure hole (71); an elastic element (100) capable of protruding from the blind hole (102) is provided in the blind hole (102), and the blind hole (102) and the elastic element (100) can constitute a force-applying mechanism for applying positive pressure to the bottom surface (7b3) of the valve body at the distal end of the high-pressure groove (7b2) of the valve body.

4. The rotary valve with preload according to claim 3, characterized in that: The elastic element (100) is a spring, a spring washer, a rubber pad or a rubber ring that can provide a restoring force after being compressed.

5. The rotary valve with preload according to any one of claims 1 to 4, characterized in that: The rotary valve seat (7a) is provided with a valve seat low-pressure hole (7a1) capable of penetrating the rotary valve seat, and the rotary valve body (7b) is provided with a valve body low-pressure hole (7b1) capable of penetrating the rotary valve body. The valve seat low-pressure hole (7a1) and the valve body low-pressure hole (7b1) constitute a low-pressure hole (71) of the rotary valve (7).

6. The rotary valve with preload according to any one of claims 1 to 4, characterized in that: The rotary valve seat (7a) and the rotary valve body (7b) are fixedly connected via a rotary valve positioning pin (103) to limit relative rotation between the two.

7. The rotary valve with preload according to claim 6, characterized in that: The accommodating cavity bottom surface (7a3) of the accommodating cavity (7a2) is provided with a valve seat locating pin hole (7a4) into which a rotary valve locating pin (103) can be inserted, and the valve body bottom surface (7b3) is provided with a valve body locating pin hole (7b4) into which a rotary valve locating pin (103) can be inserted.

8. The rotary valve with preload according to claim 7, characterized in that: The valve seat positioning pin hole (7a4) and the valve body positioning pin hole (7b4) are arranged adjacent to the low-pressure hole (71).

9. The rotary valve with preload according to any one of claims 1 to 4, characterized in that: The rotary valve seat (7a) is rotatably supported in the cover body (2) by a bearing (14).

10. A cryogenic refrigerator, comprising a gas distribution mechanism, characterized in that: The gas distribution mechanism is composed of a gas distribution valve (6) and a rotary valve (7) as described in any one of claims 1 to 9.

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