Self-locking automatic control ball valve bonnet structure capable of accurately regulating valve position and its method

Abstract

The present invention discloses a self-locking type automatic control ball valve bonnet structure capable of precisely regulating the valve position and its method, belonging to the valve field. Among them, the shaft sleeve is fixedly connected with the valve stem. The lower part of the shaft sleeve is sleeved in the sleeve, and the lower part of the sleeve is sleeved in the positioning plate, and the positioning plate is fixed on the upper surface of the bonnet. When the valve stem drives the shaft sleeve to rotate, relative static in one direction and relative rotation in another direction can be achieved between the shaft sleeve and the sleeve, and relative static in one direction and relative rotation in another direction can also be achieved between the sleeve and the positioning plate, but the cooperation direction is opposite to that between the shaft sleeve and the sleeve. The present invention realizes the function of precisely positioning the valve position during the opening and closing processes of the automatic control ball valve, thereby avoiding inaccurate valve position caused by inaccurate transmission of the motor torque, lifting the valve position during the movement of the valve stem, reducing the wear of the sealing ring and the valve seat and the torque resistance of the ball valve sphere during the process of changing the valve position, and improving the comprehensive performance of the automatic control ball valve in preventing internal leakage from multiple aspects.

Description

Technical Field

[0001] The present invention belongs to the field of valves, and particularly relates to a self-locking type automatic control ball valve bonnet structure capable of accurately adjusting the valve position and a method thereof. Background Art

[0002] The valve sealing performance refers to the ability of each sealing part of the valve to prevent the leakage of the medium, and it is an important performance index of the valve. The main function of the valve is to control the on-off flow of the medium in the pipeline. Since the internal medium is often high-temperature, high-pressure, flammable, dangerous, toxic and harmful, and as a key throttling part, it can significantly affect the working state of the entire process flow. Once leakage occurs, the consequences are very serious.

[0003] Valve leakage is divided into internal leakage and external leakage. The generation mechanism of internal leakage is relatively complex, and there are many possible reasons. For example, the closing valve position is inaccurate, the valve is not fully closed, and some medium leaks from the gap; the soft sealing ring fits tightly with the sphere and is locked, the valve stem torque is too large, and the valve opening and closing are difficult; after the valve is closed, the valve stem is not fully locked, and the medium pressure difference causes the sphere to rotate slightly; the changes in working conditions such as medium pressure and temperature cause the sealing ring to expand and contract, affecting the sealing performance and sealing specific pressure of the sealing ring; the valve is worn, the closing valve position is not very accurate or there are some changes; impurities enter the gap between the sphere and the sealing ring, resulting in valve core jamming, etc. The valve stem of the automatic control ball valve is driven by a motor, and the torque it can provide is set after leaving the factory. However, when the ball valve is put into actual use, the working conditions often face different working conditions, resulting in the torque provided by the motor not being able to fully close the ball valve, often causing false leakage. When the service life of the valve increases, improper maintenance will also cause true leakage. Therefore, aiming at the inducement of valve internal leakage, it is of great significance to study a mechanical structure and method of an automatic control ball valve capable of accurately adjusting the valve position to improve the comprehensive sealing performance of the ball valve. Summary of the Invention

[0004] The purpose of the present invention is to overcome the defects in the prior art, and provide a self-locking type automatic control ball valve bonnet structure capable of accurately adjusting the valve position and a method thereof. The present invention realizes the function of accurately positioning the valve position during the opening and closing processes of the automatic control ball valve, thereby avoiding inaccurate valve position caused by inaccurate motor torque transmission, lifting the valve position during the valve stem movement process, reducing the wear of the sealing ring and valve seat and the torque resistance of the ball valve sphere during the process of changing the valve position, using the detachable and flexible assembly of the pressing cover, realizing the convenient debugging of the valve position and sealing performance, and improving the comprehensive performance of the automatic control ball valve to prevent internal leakage from multiple aspects.

[0005] The specific technical solutions adopted by the present invention are as follows:

[0006] In the first aspect, the present invention provides a self-locking type automatic control ball valve bonnet structure capable of accurately adjusting the valve position, including a shaft sleeve, a sleeve and a positioning plate;

[0007] The bushing is of a cylindrical structure, and its bottom extends horizontally towards the outer periphery to form a first spiral disk body with four wedge-shaped teeth; the sleeve includes a first ring body and a first cylinder body coaxially connected from top to bottom. A first spiral groove matching the first spiral disk body is provided at the center of the first ring body. The first spiral groove includes a first upper sliding layer and a first lower fixing layer; four first wedge-shaped grooves are provided along the circumferential direction of the inner periphery of the first upper sliding layer, and first wedge-shaped sliders with the same rough end orientation are respectively arranged in each first wedge-shaped groove; the first wedge-shaped sliders are connected to the inner side wall of the first wedge-shaped groove by first springs capable of providing radial elastic force and can be completely retracted into the first wedge-shaped grooves; a first limiting cover is fixed at the top of the sleeve, and the first limiting cover limits the first spiral disk body between the top of the first cylinder body and the first limiting cover; when the first spiral disk body is located at the first lower fixing layer, the bushing and the sleeve are in a relatively static state; when the first spiral disk body is located at the first upper sliding layer, the bushing can only rotate relative to the sleeve in the first direction, and during the rotation, the first spiral disk body can press the first wedge-shaped sliders into the first wedge-shaped grooves;

[0008] The bottom of the first cylinder body extends horizontally towards the outer periphery to form a second spiral disk body with four wedge-shaped teeth, and the orientation of the wedge-shaped teeth of the second spiral disk body is opposite to that of the wedge-shaped teeth of the first spiral disk body; the positioning plate is of a ring structure and is fixed to the top of the valve cover. A second spiral groove matching the second spiral disk body is provided at the center of the positioning plate. The second spiral groove includes a second upper sliding layer and a second lower fixing layer; four second wedge-shaped grooves are provided along the circumferential direction of the inner periphery of the second upper sliding layer, and second wedge-shaped sliders with the same rough end orientation are respectively arranged in each second wedge-shaped groove. The rough end orientation of the second wedge-shaped sliders is opposite to that of the rough end orientation of the first wedge-shaped sliders; the second wedge-shaped sliders are connected to the inner side wall of the second wedge-shaped groove by second springs capable of providing radial elastic force and can be completely retracted into the second wedge-shaped grooves; a second limiting cover is fixed at the top of the positioning plate, and the second limiting cover limits the second spiral disk body between the bottom of the positioning plate and the second limiting cover; when the second spiral disk body is located at the second lower fixing layer, the positioning plate and the sleeve are in a relatively static state; when the second spiral disk body is located at the second upper sliding layer, the sleeve can only rotate relative to the positioning plate in the second direction, and during the rotation, the second spiral disk body can press the second wedge-shaped sliders into the second wedge-shaped grooves; the second direction is opposite to the first direction; the valve stem passes through the valve cover, the positioning plate, the second limiting cover and the sleeve from bottom to top and is sleeved and fixedly connected with the bushing.

[0009] Preferably, a pressing cover is further provided at the top of the second limiting cover, and the pressing cover is fixed to the valve cover by a plurality of second bolts to press and fix the second limiting cover and the positioning plate to the top of the valve cover.

[0010] Preferably, the first limiting cover is fixed to the top of the sleeve by a plurality of first bolts.

[0011] Preferably, the second limiting cover is fixed to the top of the positioning plate by a plurality of third bolts.

[0012] Preferably, the inner radian angles of the wedge teeth of the first spiral disc body and the second spiral disc body are both 90°.

[0013] Preferably, the height of the first lower fixing layer ≥ the height of the first upper sliding layer, and the height of the second lower fixing layer ≥ the height of the second upper sliding layer.

[0014] Preferably, both the positioning plate and the sleeve are centrosymmetric structures.

[0015] Preferably, convex corners for limiting each first wedge-shaped slider are provided between adjacent first wedge-shaped grooves, and convex corners for limiting each second wedge-shaped slider are provided between adjacent second wedge-shaped grooves.

[0016] Preferably, when the first spiral disc body is located in the first lower fixing layer, the second spiral disc body is located in the second lower fixing layer; when the first spiral disc body is located in the first upper sliding layer, the second spiral disc body is located in the second upper sliding layer.

[0017] In a second aspect, the present invention provides a valve position adjustment method using the valve cover structure of the self-locking type automatic control ball valve capable of precisely adjusting the valve position according to any one of the first aspects, specifically as follows:

[0018] When the ball valve is opened, the valve stem is lifted so that the first spiral disc body is located in the first upper sliding layer and the second spiral disc body is located in the second upper sliding layer; then the valve stem is rotated in the first direction. Due to the blocking effect of the thick end of the second wedge-shaped slider, the second spring cannot be compressed, the sleeve cannot rotate, and the valve stem drives the shaft sleeve to rotate and squeezes the first wedge-shaped slider into the first wedge-shaped groove, and the first spring is compressed until the first spiral disc body rotates 90°. The first spring rebounds and drives the first wedge-shaped slider to reset; during the opening process, the first spiral disc body will drive the valve stem to precisely rotate 90° under the action of the extrusion of the first spring and the first wedge-shaped slider, so that the ball valve is completely opened to avoid inaccurate valve position; when the ball valve is completely opened, the valve stem is lowered so that the first spiral disc body falls back into the first lower fixing layer and the second spiral disc body falls back into the second lower fixing layer, and the valve stem cannot rotate circumferentially, and the valve position is locked;

[0019] When the ball valve is closed, lift the valve stem so that the first spiral disk body is located on the first upper sliding layer and the second spiral disk body is located on the second upper sliding layer; then rotate the valve stem in the second direction. Due to the blocking effect of the thick end of the first wedge-shaped slider, the first spring cannot be compressed, and the first spiral disk body cannot rotate within the sleeve. Thus, the valve stem drives the sleeve to rotate together through the bushing. During the rotation of the sleeve, the second spiral disk body squeezes the second wedge-shaped slider into the second wedge-shaped groove, and the second spring is compressed until the second spiral disk body rotates 90°. Then the second spring rebounds and drives the second wedge-shaped slider to reset. During the closing process, the second spiral disk body will drive the valve stem to accurately rotate 90° under the action of the extrusion of the second spring and the second wedge-shaped slider, so that the ball valve is completely closed, avoiding inaccurate valve positions. When the ball valve is completely closed, let the valve stem fall, so that the first spiral disk body falls back into the first lower fixed layer and the second spiral disk body falls back into the second lower fixed layer. The valve stem cannot rotate circumferentially, and the valve position is locked, ensuring the sealing performance of the ball valve.

[0020] If there is still internal leakage of the medium when the ball valve is fully closed, rotate the positioning plate to adjust the angle of the valve stem so that the internal leakage of the medium is minimized when the ball valve is completely closed, and then fix the positioning plate.

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

[0022] The present invention realizes the functions of accurately positioning and locking the valve position during the opening and closing processes of the ball valve, reduces the wear of the sealing ring and valve seat and the torque resistance of the ball valve sphere during the process of changing the valve position, and realizes the convenient debugging of the valve position and sealing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is an exploded part drawing of the valve cover structure;

[0024] Figure 2 It is an assembled effect drawing of the valve cover structure;

[0025] Figure 3 It is a part drawing (a) and a sectional view (b) of the sleeve;

[0026] Figure 4 It is a part drawing (a) and a sectional view (b) of the positioning plate;

[0027] In the figure: 101, the first bolt; 102, the second bolt; 103, the third bolt; 201, the first limit cover; 202, the second limit cover; 3, the bushing; 401, the first spring; 402, the second spring; 5, the sleeve; 6, the pressing cover; 7, the positioning plate; 8, the valve cover; 9, the valve stem. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention will be further described and illustrated below in conjunction with the accompanying drawings and specific embodiments. The technical features of each embodiment of the present invention can be combined correspondingly without conflict.

[0029] As Figure 1 and 2 shown, a self-locking type automatic control ball valve bonnet structure capable of accurately adjusting the valve position provided by the present invention mainly includes a bushing 3, a sleeve 5 and a positioning plate 7. The bushing 3 is fixedly connected to the valve stem 9. The lower part of the bushing 3 is sleeved in the sleeve 5, the lower part of the sleeve 5 is sleeved in the positioning plate 7, and the positioning plate 7 is fixed on the upper surface of the bonnet 8. When the valve stem 9 drives the bushing 3 to rotate, relative static in one direction and relative rotation in another direction can be achieved between the bushing 3 and the sleeve 5. For example, when the bushing 3 rotates in the clockwise direction, the bushing 3 can achieve relative rotation under the limit of the top of the sleeve 5. When the bushing 3 rotates in the counterclockwise direction, relative rotation cannot be achieved between the bushing 3 and the sleeve 5, and the two are in a relatively static state. Similarly, relative static in one direction and relative rotation in another direction can also be achieved between the sleeve 5 and the positioning plate 7, but it needs to be opposite to the cooperation direction between the bushing 3 and the sleeve 5. For example, if relative rotation in the clockwise direction and relative static in the counterclockwise direction can be achieved between the bushing 3 and the sleeve 5, then relative rotation in the counterclockwise direction and relative static in the clockwise direction need to be achieved between the sleeve 5 and the positioning plate 7.

[0030] The specific composition and connection method of the bonnet structure of the present invention will be specifically described below in order to achieve the above-mentioned cooperation effect. For the convenience of description, the first direction is taken as the counterclockwise direction and the second direction is taken as the clockwise direction as an example below. However, it should be understood that in actual applications, the first direction can also be the clockwise direction and the second direction can be the counterclockwise direction. For the second case, it will not be elaborated here.

[0031] The bushing 3 is a hollow cylindrical structure, and its bottom extends horizontally outward to form a first spiral disk body with four wedge-shaped teeth, and all four wedge-shaped teeth are deflected in the clockwise direction. As Figure 3As shown, the sleeve 5 mainly includes a first ring body and a first cylinder body, and the first ring body and the first cylinder body are coaxially connected from top to bottom. A first spiral groove matching the first spiral disk body is formed in the center of the first ring body, so that the first spiral disk body can be snapped into the first spiral groove and slide up and down in the first spiral groove. The first spiral groove is divided into two layers, including a first upper sliding layer and a first lower fixed layer. On the basis of the shape of the first spiral groove, four first wedge-shaped grooves are formed in the first upper sliding layer from the inner circumference to the outer circumference, and the adjacent first wedge-shaped grooves are separated by convex corners. First wedge-shaped sliders with the same thick ends facing the same direction are respectively arranged in each first wedge-shaped groove. In this embodiment, the thick ends of the first wedge-shaped sliders face counterclockwise, and the inner circumferential radian angles of the first wedge-shaped sliders and the four wedge-shaped teeth of the first spiral disk body are both 90°, so as to ensure an accurate 90° offset when the ball valve is opened. The first wedge-shaped sliders are connected to the inner side walls of the first wedge-shaped grooves by first springs 401 capable of providing radial elastic force, and can be completely retracted into the first wedge-shaped grooves. In the initial state, the first springs 401 have no elastic force on the first wedge-shaped sliders, and the first wedge-shaped sliders are axially aligned with the inner circumference of the first spiral groove, so that the first spiral disk body can freely extend into the first spiral groove without obstruction.

[0032] A first limit cover 201 is fixed to the top of the sleeve 5. The inner diameter of the first cylinder body in the shaft sleeve 3 should be smaller than the hole where the first spiral groove is formed, so that the first spiral disk body can only slide between the top of the first cylinder body and the first limit cover 201. In this embodiment, the first limit cover 201 is detachably fixed to the top of the sleeve 5 by a plurality of first bolts 101. When the first spiral disk body slides to the position of the first lower fixed layer, the shaft sleeve 3 cannot rotate in the sleeve 5, and the shaft sleeve 3 and the sleeve 5 are in a relatively static state. When the first spiral disk body slides to the position of the first upper sliding layer, the shaft sleeve 3 can only rotate counterclockwise relative to the sleeve 5. During the rotation process, the first spiral disk body can press the first wedge-shaped sliders into the first wedge-shaped grooves. It is not until the first spiral disk body rotates 90° that the first wedge-shaped sliders will bounce back and reset under the action of the first springs 401.

[0033] The bottom of the first cylinder body extends horizontally outward to form a second spiral disk body with four wedge-shaped teeth. The orientations of the wedge-shaped teeth of the second spiral disk body are opposite to those of the wedge-shaped teeth of the first spiral disk body. That is, in this embodiment, the four wedge-shaped teeth of the second spiral disk body are all deflected counterclockwise. As Figure 4As shown, the positioning plate 7 is a ring structure and is fixed to the top of the valve cover 8. A second spiral groove matching the second spiral disk body is provided at the center of the positioning plate 7, enabling the second spiral disk body to be snap-fitted into the second spiral groove and slide up and down in the second spiral groove. The second spiral groove is divided into two layers, including a second upper sliding layer and a second lower fixing layer. Based on the shape of the second spiral groove, four second wedge-shaped grooves are further formed in the second upper sliding layer from the inner circumference to the outer circumference. Adjacent second wedge-shaped grooves are separated by convex corners. Second wedge-shaped sliders with the same thick-end orientation are respectively provided in each second wedge-shaped groove, and the thick-end orientation of the second wedge-shaped sliders is opposite to that of the first wedge-shaped sliders. For example, in this embodiment, the thick ends of the second wedge-shaped sliders face the clockwise direction, and the inner circumferential radian angles of the second wedge-shaped sliders and the four wedge-shaped teeth of the second spiral disk body are both 90°, so as to ensure an accurate 90° offset when the ball valve is closed. The second wedge-shaped sliders are connected to the inner side walls of the second wedge-shaped grooves by second springs 402 capable of providing radial elastic force and can be completely retracted into the second wedge-shaped grooves. In the initial state, the second springs 402 have no elastic force on the second wedge-shaped sliders, and the second wedge-shaped sliders are axially aligned with the inner circumference of the second spiral groove, enabling the second spiral disk body to freely extend into the second spiral groove without obstruction.

[0034] A second limit cover 202 is fixed to the top of the positioning plate 7. The inner diameter of the bottom of the positioning plate 7 should be smaller than the hole where the second spiral groove is formed, so that the second spiral disk body can only slide between the bottom of the positioning plate 7 and the second limit cover 202. In this embodiment, the second limit cover 202 is fixed to the top of the positioning plate 7 by a plurality of third bolts 103. At the same time, the positioning plate 7 is fixed to the top of the valve cover 8 by a pressing cover 6. The specific structure is as follows: A pressing cover 6 is provided on the top of the second limit cover 202, and the pressing cover 6 is fixed to the valve cover 8 by a plurality of second bolts 102 to press and fix the second limit cover 202 and the positioning plate 7 to the top of the valve cover 8. Under the above structure, when the second spiral disk body slides to the second lower fixing layer, the sleeve 5 cannot slide in the positioning plate 7, and the positioning plate 7 and the sleeve 5 are in a relatively static state. When the second spiral disk body slides to the second upper sliding layer, the sleeve 5 can only rotate relative to the positioning plate 7 in the clockwise direction. During the rotation, the second spiral disk body can press the second wedge-shaped sliders into the second wedge-shaped grooves. It is not until the second spiral disk body rotates 90° that the second wedge-shaped sliders will bounce back to their original positions under the action of the second springs 402. The valve stem 9 passes through the valve cover 8, the positioning plate 7, the second limit cover 202, and the sleeve 5 from bottom to top and is sleeved and fixedly connected to the bushing 3.

[0035] In practical applications, both the positioning plate 7 and the sleeve 5 can adopt a centrally symmetrical structure. By adjusting the thickness ratio of the first spiral disk body, the second spiral disk body, the first upper sliding layer, the first lower fixed layer, the second upper sliding layer and the second lower fixed layer, when the first spiral disk body is located at the first lower fixed layer, the second spiral disk body is located at the second lower fixed layer, and when the first spiral disk body is located at the first upper sliding layer, the second spiral disk body is located at the second upper sliding layer. Preferably, the height of the first lower fixed layer is ≥ the height of the first upper sliding layer, and the height of the second lower fixed layer is ≥ the height of the second upper sliding layer. In this embodiment, the thickness of the first spiral disk body, the second spiral disk body, the first upper sliding layer, the first lower fixed layer, the second upper sliding layer and the second lower fixed layer are the same, and an equal height structure is adopted.

[0036] The valve position adjustment method using the self-locking automatic control ball valve bonnet structure capable of accurately adjusting the valve position is as follows:

[0037] When the ball valve needs to be opened or closed, the motor will act on the valve stem 9 to lift it a certain distance. At this time, the lower end of the ball of the fixed ball valve will separate from the ball valve base, reducing the wear of the valve seat and the ball due to the friction between the lower end of the ball and the valve seat during the rotation of the ball; at the same time, due to the lifting of the pre-tightening position for a certain distance, the pre-tightening force between the side of the ball and the sealing ring decreases, alleviating the situation where the torque of the valve stem 9 is too large due to the locking of the sealing ring, causing the valve core to get stuck and the valve is difficult to open and close.

[0038] When the ball valve is opened, first lift the valve stem 9 so that the first spiral disc is located in the first upper sliding layer and the second spiral disc is located in the second upper sliding layer. Then rotate the valve stem 9 in the counterclockwise direction. Due to the blocking effect of the thick end of the second wedge-shaped slider, the second spring 402 cannot be compressed, and the sleeve 5 cannot rotate. The valve stem 9 drives the shaft sleeve 3 to rotate and squeezes the first wedge-shaped slider into the first wedge-shaped groove. The first spring 401 is compressed until the first spiral disc rotates 90°. The first spring 401 bounces up and drives the first wedge-shaped slider to reset. During the opening process, the first spiral disc will drive the valve stem 9 to rotate accurately 90° under the action of the first spring 401 and the first wedge slider, so that the ball valve is fully opened, avoiding the occurrence of inaccurate valve position. When the ball valve is fully opened, the valve stem 9 is allowed to fall back, so that the first spiral disc falls back to the first lower fixed layer, and the second spiral disc falls back to the second lower fixed layer. The valve stem 9 cannot rotate circumferentially, and the valve position is locked at this time.

[0039] When the ball valve is closed, the valve stem 9 is lifted so that the first spiral disc body is located on the first upper sliding layer and the second spiral disc body is located on the second upper sliding layer. Subsequently, the valve stem 9 is rotated clockwise. Due to the blocking effect of the thick end of the first wedge-shaped slider, the first spring 401 cannot be compressed, and the first spiral disc body cannot rotate within the sleeve 5. Thus, the valve stem 9 drives the sleeve 5 to rotate together through the bushing 3. During the rotation of the sleeve 5, the second spiral disc body squeezes the second wedge-shaped slider into the second wedge-shaped groove, and the second spring 402 is compressed until the second spiral disc body rotates 90°. Then the second spring 402 rebounds and drives the second wedge-shaped slider to reset. During the closing process, the second spiral disc body drives the valve stem 9 to accurately rotate 90° under the action of the extrusion of the second spring 402 and the second wedge-shaped slider, so that the ball valve is completely closed, avoiding the occurrence of inaccurate valve positions. After the ball valve is completely closed, the valve stem 9 is lowered so that the first spiral disc body falls back into the first lower fixed layer and the second spiral disc body falls back into the second lower fixed layer. The valve stem 9 cannot rotate circumferentially. At this time, the valve position is locked and completely closed, ensuring the sealing performance of the ball valve.

[0040] If the set angle is unreasonable and there is still internal leakage of the medium when the valve is fully closed, the angle of the valve stem 9 needs to be adjusted to ensure the sealing performance. The method is to loosen the second bolt 102 and remove the pressing cover 6. At this time, the positioning plate 7 can rotate circumferentially. The positioning plate 7 is finely adjusted until the valve is fully closed and the internal leakage reaches the minimum. Then the pressing cover 6 is installed again using the second bolt 102. At this time, the set angle reaches the state with the optimal sealing performance.

[0041] The present invention realizes the function of accurately positioning the valve position during the opening and closing processes of the automatic control ball valve, thus avoiding inaccurate valve positions caused by inaccurate transmission of the motor torque. The valve position is lifted during the movement of the valve stem, reducing the wear of the sealing ring and valve seat and the torque resistance of the ball of the ball valve during the process of changing the valve position. The detachable and flexible assembly of the pressing cover is used to realize the convenient debugging of the valve position and sealing performance, improving the comprehensive performance of the automatic control ball valve to prevent internal leakage in multiple aspects.

[0042] The above-described embodiments are only a preferred solution of the present invention, but they are not intended to limit the present invention. Those of ordinary skill in the relevant technical fields can still make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all technical solutions obtained by means of equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A self-locking type automatic control ball valve bonnet structure capable of accurately adjusting the valve position, Characterized in that, it includes a bushing (3), a sleeve (5) and a positioning plate (7); The bushing (3) is a cylindrical structure, and its bottom extends horizontally outward to form a first spiral disk body with four wedge teeth; the sleeve (5) includes a first ring body and a first cylinder body coaxially connected from top to bottom. A first spiral groove matching the first spiral disk body is opened in the center of the first ring body. The first spiral groove includes a first upper sliding layer and a first lower fixing layer; four first wedge grooves are opened along the inner circumference of the first upper sliding layer, and a first wedge-shaped slider with the same thick end orientation is respectively arranged in each first wedge groove; the first wedge-shaped slider is connected to the inner side wall of the first wedge groove by a first spring (401) capable of providing radial elastic force, and can be completely retracted into the first wedge groove; a first limit cover (201) is fixed on the top of the sleeve (5), and the first limit cover (201) limits the first spiral disk body between the top of the first cylinder body and the first limit cover (201); when the first spiral disk body is located at the first lower fixing layer, the bushing (3) and the sleeve (5) are in a relatively static state; when the first spiral disk body is located at the first upper sliding layer, the bushing (3) can only rotate relative to the sleeve (5) in the first direction, and during the rotation, the first spiral disk body can press the first wedge-shaped slider into the first wedge groove; The bottom of the first cylinder body extends horizontally outward to form a second spiral disk body with four wedge teeth, and the orientation of the wedge teeth of the second spiral disk body is opposite to that of the wedge teeth of the first spiral disk body; the positioning plate (7) is a ring structure, fixed on the top of the bonnet (8), and a second spiral groove matching the second spiral disk body is opened in the center of the positioning plate (7). The second spiral groove includes a second upper sliding layer and a second lower fixing layer; four second wedge grooves are opened along the inner circumference of the second upper sliding layer, and a second wedge-shaped slider with the same thick end orientation is respectively arranged in each second wedge groove. The thick end orientation of the second wedge-shaped slider is opposite to that of the first wedge-shaped slider; the second wedge-shaped slider is connected to the inner side wall of the second wedge groove by a second spring (402) capable of providing radial elastic force, and can be completely retracted into the second wedge groove; a second limit cover (202) is fixed on the top of the positioning plate (7), and the second limit cover (202) limits the second spiral disk body between the bottom of the positioning plate (7) and the second limit cover (202); when the second spiral disk body is located at the second lower fixing layer, the positioning plate (7) and the sleeve (5) are in a relatively static state; when the second spiral disk body is located at the second upper sliding layer, the sleeve (5) can only rotate relative to the positioning plate (7) in the second direction, and during the rotation, the second spiral disk body can press the second wedge-shaped slider into the second wedge groove; the second direction is opposite to the first direction; the valve stem (9) sequentially passes through the bonnet (8), the positioning plate (7), the second limit cover (202) and the sleeve (5) from bottom to top and is sleeved and fixedly connected with the bushing (3).

2. The self-locking type automatic control ball valve bonnet structure capable of accurately adjusting the valve position according to claim 1, Characterized in that, A pressing cover (6) is further provided on the top of the second limiting cover (202). The pressing cover (6) is fixed to the valve cover (8) by a plurality of second bolts (102) so as to press and fix the second limiting cover (202) and the positioning plate (7) on the top of the valve cover (8).

3. The valve cover structure of a self-locking type automatic control ball valve capable of accurately adjusting the valve position according to claim 1, characterized in that, the first limiting cover (201) is fixed to the top of the sleeve (5) by a plurality of first bolts (101).

4. The valve cover structure of a self-locking type automatic control ball valve capable of accurately adjusting the valve position according to claim 1, characterized in that, the second limiting cover (202) is fixed to the top of the positioning plate (7) by a plurality of third bolts (103).

5. The valve cover structure of a self-locking type automatic control ball valve capable of accurately adjusting the valve position according to claim 1, characterized in that, the inner radian angles of the wedge teeth of the first spiral disk body and the second spiral disk body are both 90°.

6. The valve cover structure of a self-locking type automatic control ball valve capable of accurately adjusting the valve position according to claim 1, characterized in that, the height of the first lower fixing layer ≥ the height of the first upper sliding layer, and the height of the second lower fixing layer ≥ the height of the second upper sliding layer.

7. The valve cover structure of a self-locking type automatic control ball valve capable of accurately adjusting the valve position according to claim 1, characterized in that, the positioning plate (7) and the sleeve (5) are both centrosymmetric structures.

8. The valve cover structure of a self-locking type automatic control ball valve capable of accurately adjusting the valve position according to claim 1, characterized in that, convex corners for limiting each first wedge-shaped slider are provided between adjacent first wedge-shaped grooves, and convex corners for limiting each second wedge-shaped slider are provided between adjacent second wedge-shaped grooves.

9. The valve cover structure of a self-locking type automatic control ball valve capable of accurately adjusting the valve position according to claim 1, characterized in that, when the first spiral disk body is located in the first lower fixing layer, the second spiral disk body is located in the second lower fixing layer; when the first spiral disk body is located in the first upper sliding layer, the second spiral disk body is located in the second upper sliding layer.

10. A valve position adjusting method using the valve cover structure of a self-locking type automatic control ball valve capable of accurately adjusting the valve position according to any one of claims 1 to 9, characterized in that, specifically as follows: When the ball valve is opened, the valve stem (9) is lifted so that the first spiral disk body is located on the first upper sliding layer and the second spiral disk body is located on the second upper sliding layer; then the valve stem (9) is rotated in the first direction. Due to the blocking effect of the thick end of the second wedge-shaped slider, the second spring (402) cannot be compressed, the sleeve (5) cannot rotate, and the valve stem (9) drives the bushing (3) to rotate and squeezes the first wedge-shaped slider into the first wedge-shaped groove. The first spring (401) is compressed until the first spiral disk body rotates 90°. The first spring (401) rebounds and drives the first wedge-shaped slider to reset; during the opening process, the first spiral disk body will drive the valve stem (9) to accurately rotate 90° under the action of the extrusion of the first spring (401) and the first wedge-shaped slider, so that the ball valve is fully opened, avoiding inaccurate valve positions; after the ball valve is fully opened, the valve stem (9) is lowered so that the first spiral disk body falls back into the first lower fixed layer and the second spiral disk body falls back into the second lower fixed layer. The valve stem (9) cannot rotate circumferentially and the valve position is locked; When the ball valve is closed, the valve stem (9) is lifted so that the first spiral disk body is located on the first upper sliding layer and the second spiral disk body is located on the second upper sliding layer; then the valve stem (9) is rotated in the second direction. Due to the blocking effect of the thick end of the first wedge-shaped slider, the first spring (401) cannot be compressed, and the first spiral disk body cannot rotate in the sleeve (5), so that the valve stem (9) drives the sleeve (5) to rotate together through the bushing (3); during the rotation of the sleeve (5), the second spiral disk body squeezes the second wedge-shaped slider into the second wedge-shaped groove, and the second spring (402) is compressed until the second spiral disk body rotates 90°. The second spring (402) rebounds and drives the second wedge-shaped slider to reset; during the closing process, the second spiral disk body will drive the valve stem (9) to accurately rotate 90° under the action of the extrusion of the second spring (402) and the second wedge-shaped slider, so that the ball valve is fully closed, avoiding inaccurate valve positions; after the ball valve is fully closed, the valve stem (9) is lowered so that the first spiral disk body falls back into the first lower fixed layer and the second spiral disk body falls back into the second lower fixed layer. The valve stem (9) cannot rotate circumferentially and the valve position is locked, ensuring the sealing performance of the ball valve; If there is still internal leakage of the medium when the ball valve is fully closed, the valve stem (9) angle is adjusted by rotating the positioning plate (7) to minimize the internal leakage of the medium when the ball valve is fully closed, and then the positioning plate (7) is fixed.

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