Cam type control rod driving mechanism and control method

Abstract

The invention relates to the field of pressurized water reactor nuclear power stations, in particular to a cam type control rod driving mechanism and a control method. The device is arranged in the center of an upper supporting plate of the pressure vessel and comprises a mechanism shell, a driving rod penetrating through the mechanism shell is arranged in the mechanism shell, the lower end of the driving rod is connected with a clamping plate, a plurality of control rods are installed on the clamping plate, a driving assembly is arranged on the mechanism shell, and a clamping assembly is arranged in the mechanism shell. The clamping assembly comprises a movable clamping set and a fixed clamping set, the movable clamping set and the fixed clamping set make contact with the driving assembly, the movable clamping set is located above the fixed clamping set, and the driving assembly operates to control the time sequence of the movable clamping set and the fixed clamping set for clamping the driving rod. And the driving assembly is matched with the clamping assembly, so that the driving rod realizes lifting motion. And the operation of controlling a plurality of assemblies to sequentially execute functions by controlling a plurality of groups of electromagnets is omitted, the assembly control and driving process is simplified, and the problems of jamming, damage and the like caused by improper matching are avoided.

Description

Technical Field

[0001] This invention relates to the field of pressurized water reactor nuclear power plant technology, and in particular to a cam-type control rod drive mechanism and control method. Background Technology

[0002] The control rod drive mechanism, also known as the control rod drive mechanism (CRDM), is a servo mechanism of the nuclear power plant reactor control system and safety protection system. It is responsible for reactor startup, power regulation, shutdown, and rapid shutdown in case of an accident. Under normal operating conditions, the mechanism moves the control rods at approximately 10 mm / s. In case of an accident, it can complete the shutdown operation within 2 seconds. Its design life is equivalent to that of the reactor and it must meet technical requirements such as shock resistance and anti-stick jamming.

[0003] The control rod drive mechanism is an electromechanical device in a nuclear reactor used to adjust the position of the control rods. It consists of components such as a drive rod, a claw, a pressure vessel, and a magnetic yoke coil. It uses magnetic lifting to achieve step-by-step movement of the control rods and undertakes functions such as reactor startup, power regulation, and emergency shutdown. The mechanism drives the armature to move by sequentially energizing three sets of electromagnetic coils. The traction claw alternately engages with the annular groove of the drive rod, enabling it to complete a step-by-step movement within 150ms and rapidly lower the control rod within 2 seconds. During installation, it is connected to the reactor pressure vessel top cover pipe seat via a threaded connection through the pressure vessel and sealed by Ω-welding.

[0004] The control rod drive mechanism (CRDM) is a crucial component of the control and safety protection system for pressurized water reactors. It controls the reactor's start-up and shutdown and regulates reaction power by driving control rods to perform lifting, lowering, holding, or quick insertion actions. Current control rod drive mechanisms are complex, requiring multiple components such as latches, springs, and pawls to control multiple sets of electromagnets to execute functions sequentially, with close coordination in timing. This demands tight coordination between the electromagnets, resulting in poor continuity of motion and low drive efficiency, and prolonged response time for electromagnetic drives in emergency situations.

[0005] To simplify the control components and drive process, and to improve the response efficiency of the drive mechanism, there is an urgent need for a cam-type control rod drive mechanism and control method. Summary of the Invention

[0006] The present invention aims to solve the above problems, thereby providing a cam-type control rod drive mechanism and control method, which eliminates the need to control multiple components to execute functions sequentially by controlling multiple sets of electromagnets, simplifies the control components and drive process, avoids problems such as jamming and damage caused by improper coordination, improves the lifting efficiency of the control rod, and improves the response rate of the clamping components.

[0007] The technical solution adopted by the present invention to solve the aforementioned problem is as follows: A cam-type control rod drive mechanism is located at the center of the upper support plate of a pressure vessel. It includes a housing, a drive rod extending through the housing along its height, a clamping plate connected to the lower end of the drive rod, and several control rods mounted on the clamping plate. A drive assembly is mounted on the housing, and a clamping assembly is located inside the housing. The clamping assembly includes a movable clamping group and a fixed clamping group, both of which are in contact with the drive assembly. The movable clamping group is located above the fixed clamping group. The drive assembly operates to control the timing of the movable and fixed clamping groups clamping the drive rod. The drive assembly and the clamping assembly cooperate to achieve the lifting and lowering movement of the drive rod.

[0008] Furthermore, the drive assembly includes a drive motor disposed on the outer wall of the mechanism housing, a camshaft drivenly connected to the drive motor, and the camshaft extends through the outer wall of the mechanism housing into the mechanism housing. Two cams are fixedly connected to the camshaft, and the two cams are spaced apart along the axial direction. Two first arc protrusions with the same structure are provided on the outer surface of one of the cams, and the movable clamping assembly contacts the two first arc protrusions. Two second arc protrusions with the same structure are provided on the inner surface of the other cam, and the fixed clamping assembly contacts the two second arc protrusions.

[0009] Furthermore, upper support plates are provided at the four corners inside the outer shell of the mechanism, and the four upper support plates are at the same horizontal height. The movable clamping assembly is placed on the four upper support plates. Lower support plates are provided at the four corners inside the outer shell of the mechanism, and the four lower support plates are at the same horizontal height. The fixed clamping assembly is placed on the four lower support plates.

[0010] Furthermore, the movable clamping assembly includes a left clamping component and a right clamping component. The left and right clamping components have the same structure and are symmetrically arranged around the drive rod. Both the left and right clamping components include movable connecting plates disposed on two upper support plates on the same side. The movable connecting plates are located directly above the cam, and the distance between the movable connecting plates and the cam is less than the height of the cam. The bottom surface of the movable connecting plates is in contact with the cam. Movable clamping parts adapted to the drive rod are fixedly connected to the movable connecting plates. First spring connecting seats are fixedly connected to the movable connecting plates. First connecting springs are connected to both first spring connecting seats. The two movable clamping parts and the first connecting springs cooperate to clamp the drive rod. Trapezoidal wedges are fixedly connected to the movable connecting plates near the two first arc protrusions. The trapezoidal wedges are located between the two first arc protrusions and are in contact with the two first arc protrusions.

[0011] Furthermore, spring limit rods are vertically fixed on both movable connecting plates, and limit springs are fitted on the spring limit rods. The limit springs are located between the inner wall of the mechanism housing and the movable connecting plate. Through holes corresponding to the two spring limit rods are provided on the upper end face of the mechanism housing.

[0012] Furthermore, the fixed clamping assembly includes a left clamping component and a right clamping component. The left and right clamping components have the same structure and are symmetrically arranged with the drive rod as the center. Both the left and right clamping components include fixed connecting plates on two lower support plates on the same side. Fixed clamping parts adapted to the drive rod are fixedly connected to the fixed connecting plates. Electromagnets are fixedly connected to the fixed connecting plates. The magnetic poles of the two electromagnets are opposite to each other on their opposite sides. The two fixed clamping parts and the two electromagnets work together to clamp the drive rod. Electromagnetic switches are fixedly connected to the fixed connecting plates near the two second arc protrusions. Both electromagnets are connected to the electromagnet switch circuit. The electromagnet switches are located between and in contact with the two second arc protrusions. Second spring connecting seats are fixedly connected to the fixed connecting plates. A first compression spring is connected to both second spring connecting seats.

[0013] Furthermore, the electromagnet switch includes a switch base fixed to a fixed connecting plate, a limit seat fixedly connected to the upper end of the switch base, a displacement groove provided on the limit seat, the opening direction of the displacement groove being away from the cam, a horizontal column rotatably connected to the limit seat and passing through the displacement groove, a vertical column fixedly fixed in the center of the horizontal column, the vertical column being located between and in contact with the two second arc protrusions, a horizontal limit baffle fixed to the horizontal column being provided in the displacement groove, the horizontal limit baffle being located on the side of the horizontal column away from the cam, a second compression spring being fixedly connected between the horizontal limit baffle and the switch base, two circuit contacts being provided on the wall surface of the displacement groove near the cam, the two circuit contacts being connected to two electromagnet circuits, and the vertical column being in contact with the two circuit contacts.

[0014] Furthermore, a coaxial through hole is provided on both the upper and lower end faces of the mechanism housing, the drive rod is placed in the through hole, and several annular grooves are arranged at intervals from top to bottom on the upper part of the drive rod.

[0015] Furthermore, the movable clamping component and the fixed clamping component have the same structure, both including a vertical plate. Several clamping teeth that are adapted to the annular groove are provided on the side of the vertical plate near the drive rod, and a reinforcing rib plate that is connected to the movable connecting plate or the fixed connecting plate is fixed on the side of the vertical plate away from the drive rod.

[0016] A control method for a cam-type control rod drive mechanism includes the following steps: S1. Assemble the cam-type control rod drive mechanism, set it at the center of the upper support plate of the pressure vessel, and conduct a pre-lifting test by powering on it to ensure that the cam-type control rod drive mechanism operates normally. S2. When the control rod needs to rise, the drive motor is activated, causing the cam to rotate clockwise. This causes the first arc-shaped protrusion to press against the trapezoidal wedge and compress the first connecting spring, thereby moving the movable clamping member to hold the drive rod via the movable connecting plate. Simultaneously, the second arc-shaped protrusion presses against the electromagnet switch, causing the vertical column to rotate away from the cam by a certain angle and become closed, thus releasing the first compression spring and loosening the fixed clamping member. The movable clamping member rises along with the cam via the movable connecting plate, compressing the two limit springs until the cam rotates 90° to reach its highest point. Just before reaching the highest point, the second arc-shaped protrusion stops pressing against the electromagnet switch and springs back to the open state. The fixed connecting plate moves towards the drive rod under the action of the electromagnet, causing the fixed clamping member to hold the drive rod. Subsequently, the first arc-shaped protrusion stops pressing against the trapezoidal wedge, and the first connecting spring springs back to its natural state, simultaneously releasing the movable clamping member. The cam continues to rotate and causes the movable connecting plate to descend until it rotates 180°, returning to the initial state. S3. When the control rod needs to descend, the cam-type control rod drive mechanism can descend by making the cam rotation direction opposite to the rotation direction during the ascent process in the initial state, as described above. S4. In an emergency, the control cam can stop rotating to clamp the drive rod, thereby securing the control rod in an emergency. Alternatively, the cam-type control rod drive mechanism can be de-energized, and the electromagnet will stop functioning. The rebound force generated by the first compression spring will loosen the fixed clamping component. The rebound force generated by the two compressed limit springs will return the cam to its initial position, loosening the moving clamping component and allowing the control rod to be quickly inserted into the fuel assembly.

[0017] The present invention, which adopts the above technical solution, has the following prominent features compared with the prior art: The cam-type control rod drive mechanism of the present invention includes a mechanism housing, a drive rod, a drive assembly, and a clamping assembly. The clamping assembly includes a movable clamping group and a fixed clamping group. The drive assembly operates to control the timing of the movable clamping group and the fixed clamping group clamping the drive rod. The drive assembly and the clamping assembly cooperate to enable the drive rod to perform lifting and lowering movements. The above structure not only eliminates the need to control multiple components to execute functions sequentially by controlling multiple sets of electromagnets, but also simplifies the control assembly and drive process, avoiding problems such as jamming and damage caused by improper coordination. Furthermore, the cam-type control rod drive mechanism improves the lifting and lowering efficiency of the control rod and the response rate of the clamping assembly, thereby improving the motion continuity and drive efficiency of the cam-type control rod drive mechanism. Attached Figure Description

[0018] Figure 1This is a schematic diagram of the main view structure of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the main view structure of the present invention. Figure 2 ; Figure 3 yes Figure 2 A schematic diagram of a partially enlarged structure; Figure 4 This is a schematic diagram of the main structure of the electromagnet switch of the present invention; Figure 5 This is a schematic diagram of the side cross-sectional structure of the electromagnet switch of the present invention; In the diagram: 1. Mechanism housing; 2. Drive rod; 3. Clamping plate; 4. Control rod; 5. Camshaft; 6. Cam; 7. First arc protrusion; 8. Second arc protrusion; 9. Square support plate; 10. Right-angle limiting plate; 11. Moving connecting plate; 12. Moving clamping component; 13. First spring connecting seat; 14. First connecting spring; 15. Trapezoidal wedge; 16. Spring limiting rod; 17. Through hole; 18. Limiting spring; 19. Fixed connection 20. Connecting plate; 21. Fixing clamp; 22. Electromagnet; 23. Electromagnet switch; 24. Second spring connecting seat; 25. First compression spring; 26. Switch base; 27. Limit seat; 28. Displacement groove; 29. ​​Horizontal column; 30. Vertical column; 31. Horizontal limit baffle; 32. Second compression spring; 33. Circuit contact; 34. Through hole; 35. Annular groove; 36. Vertical plate; 37. Clamping teeth; 38. Reinforcing rib. Detailed Implementation

[0019] The following description of the embodiments will help the public better understand the present invention. However, the specific embodiments provided by the applicant should not and should not be regarded as a limitation on the technical solution of the present invention. Any changes to the definition of components or technical features and / or formal but not substantive changes to the overall structure should be regarded as the scope of protection defined by the technical solution of the present invention.

[0020] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0022] In this invention, terms such as "upper," "lower," "left," "right," "front," "back," "vertical," "horizontal," "side," and "bottom" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are used only to facilitate the description of the structural relationships of the various components or elements of this invention and do not specifically refer to any component or element in this invention. They should not be construed as limiting the invention.

[0023] In this invention, terms such as "fixed connection," "connected," and "linked" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of these terms in this invention based on the specific circumstances, and they should not be construed as limitations on the invention.

[0024] See Figures 1 to 5 As shown, the technical solution of the present invention is as follows: A cam-type control rod drive mechanism is located at the center of the upper support plate of a pressure vessel. It includes a housing 1, which is a rectangular structure made of steel or iron plates and has a hollow interior. A drive rod 2 is installed inside the housing 1, extending through it along its height. A clamping plate 3 is connected to the lower end of the drive rod 2. The clamping plate 3 has several clamping holes, each housing a control rod 4. The number of clamping holes on the clamping plate 3 varies depending on the usage requirements of the control rod 4. A drive assembly is installed on the housing 1, and a clamping assembly is installed inside the housing 1. The clamping assembly includes a movable clamping group and a fixed clamping group, both of which are in contact with the drive assembly. The movable clamping group is located above the fixed clamping group. The drive assembly operates to control the timing of the movable and fixed clamping groups clamping the drive rod 2. The drive assembly and the clamping assembly cooperate to achieve the lifting and lowering movement of the drive rod 2.

[0025] The drive assembly includes a drive motor. Any rotary motor that meets the power requirements for lifting and has forward and reverse rotation functions can be used as the drive motor. The motor speed and reducer are selected according to the required speed. The drive motor is fixed to the outer wall of the mechanism housing 1. A camshaft 5 is connected to the drive motor and extends through the outer wall of the mechanism housing 1 into the mechanism housing 1. Two cams 6 are fixedly connected to the camshaft 5. The two cams 6 are spaced apart along the axial direction of the camshaft 5. Two first arc protrusions 7 are fixed on the outer surface of one of the cams 6. The two first arc protrusions 7 have the same structure and are symmetrically arranged about the central axis of the cam 6. The movable clamping assembly and the two first arc protrusions 7 are connected together. A first arc protrusion 7 contacts the second arc protrusion 8, and a second arc protrusion 8 is provided on the inner side of another cam 6. The two second arc protrusions 8 have the same structure and are symmetrically arranged about the central axis of the cam 6. The fixed clamping assembly contacts the two second arc protrusions 8. The first arc protrusion 7 and the second arc protrusion 8 are both of inferior arc shape, and the length of the first arc protrusion 7 is greater than the length of the second arc protrusion 8. Both first arc protrusions 7 are quarter arcs. The above-mentioned structural arrangement of the first arc protrusion 7 and the second arc protrusion 8 makes the moving clamping member 12 clamp before the fixed clamping member 20 and release after the fixed clamping member 20, so as to ensure positioning during movement.

[0026] Upper support plates are fixed at the four corners inside the outer casing 1 of the mechanism. The four upper support plates are at the same horizontal height. The movable clamping assembly is placed on the four upper support plates, and there is no fixed connection between the movable clamping assembly and the four upper support plates. Lower support plates are fixed at the four corners inside the outer casing 1 of the mechanism. The four lower support plates are at the same horizontal height, and the fixed clamping assembly is placed on the four lower support plates. The four upper support plates are all located above the four lower support plates and have the same structure. Each of them includes a square support plate 9. The square support plate 9 is made of steel plate or iron plate and is welded and fixed to the corresponding corners inside the outer casing 1 of the mechanism. A right-angle limiting plate 10 is welded and fixed to the upper surface of the square support plate 9. The movable clamping assembly or the fixed clamping assembly is placed at the right-angle limiting plate 10. The above-mentioned structural arrangement can prevent the movable clamping component 12 and the fixed clamping component 20 from failing to be properly positioned and clamped. At the same time, the four upper support plates also prevent the movable connecting plate 11 from exceeding the limit when it descends.

[0027] The movable clamping assembly includes a left clamping component and a right clamping component. The left and right clamping components have identical structures and are symmetrically arranged around the drive rod 2. Both the left and right clamping components include a long, narrow movable connecting plate 11. The movable connecting plate 11 is placed on two upper support plates on the same side, with its right angle abutting against two right-angle limiting plates 10 on the same side. The movable connecting plate 11 is located directly above the cam 6, and the distance between the movable connecting plate 11 and the cam 6 is less than the height of the cam 6. The lower surface of plate 11 contacts cam 6. A movable clamping member 12 is fixedly connected to the movable connecting plate 11. The movable clamping member 12 is close to and adapted to the drive rod 2. A first spring connecting seat 13 is fixedly connected to the movable connecting plate 11. The first spring connecting seat 13 is located on the right side of the movable clamping member 12. A first connecting spring 14 is connected to the first spring connecting seat 13 on both the left and right clamping members. In its natural state, the first connecting spring 14 has no compression. The two movable clamping members 1 2 and the first connecting spring 14 work together to clamp the drive rod 2. A trapezoidal wedge 15 is fixedly connected to the movable connecting plate 11 near the two first arc protrusions 7. The trapezoidal wedge 15 is located between the two first arc protrusions 7, and the two inclined surfaces of the trapezoidal wedge 15 are in contact with the two first arc protrusions 7 respectively. The two first arc protrusions 7 are configured to compress the trapezoidal wedge 15. In the initial state, the corresponding first arc protrusions 7 first contact the inclined surfaces of the trapezoidal wedge 15. The contact parts rotate with the cam 6 and produce friction with the inclined surfaces. Due to the restriction of the right-angle limiting plate 10, the movable connecting plate 11 can only move left and right in the horizontal direction, thereby causing the trapezoidal wedge block 15 to move in the direction of the first connecting spring 14, which in turn drives the movable connecting plate 11 to drive the movable clamping member 12 to clamp the drive rod 2; when the first arc protrusion 7 moves away from the trapezoidal wedge block 15 as the cam 6 continues to rotate, the compressed first connecting spring 14 rebounds, causing the movable connecting plate 11 to move in the opposite direction of the above clamping process, thereby driving the movable clamping member 12 to release the drive rod 2.

[0028] Spring limiting rods 16 are vertically fixed on both movable connecting plates 11. Two through holes 17 are reserved on the upper end face of the mechanism housing 1, and the two through holes 17 correspond one-to-one with the two spring limiting rods 16. The spring limiting rods 16 can extend upward out of the mechanism housing 1 through the through holes 17. Limiting springs 18 are fitted on both spring limiting rods 16. The limiting springs 18 are fixed between the inner wall of the mechanism housing 1 and the movable connecting plate 11. In the natural state, neither of the two limiting springs 18 has any compression. The above-mentioned structural arrangement ensures that when the two limiting springs 18 are compressed, the spring limiting rods 16 pass through the through holes 17 and out of the mechanism housing 1, so as to ensure that the lifting and lowering does not cause overturning and that the drive rod 2 can move normally. Since the displacement of the cam 6 in each cycle is determined, setting the maximum number of rotations in a certain direction can ensure that the limit is not exceeded.

[0029] The fixed clamping assembly includes a left clamping component and a right clamping component. The left and right clamping components have the same structure and are symmetrically arranged around the drive rod 2. Both the left and right clamping components include a long strip-shaped fixed connecting plate 19, which is placed on two lower support plates on the same side. The right angle of the fixed connecting plate 19 abuts against two right angle limiting plates 10 on the same side. A fixed clamping member 20 is fixedly connected to the fixed connecting plate 19. The fixed clamping member 20 is close to and adapted to the drive rod 2. An electromagnet 21 is fixedly connected to the fixed connecting plate 19. The opposing magnetic poles of the iron 21 sides are opposite. Two fixed clamping parts 20 and two electromagnets 21 work together to clamp the drive rod 2. An electromagnet switch 22 is bolted to a fixed connecting plate 19 near the two second arc protrusions 8. Both electromagnets 21 are electrically connected to the electromagnet switch 22. The electromagnet switch 22 is located between the two second arc protrusions 8 and is in contact with them. A second spring connecting seat 23 is fixedly connected to the fixed connecting plate 19, and a first compression spring 24 is connected to both second spring connecting seats 23. The two second spring connecting seats 23... The two arc-shaped protrusions 8 are configured to compress the electromagnet switch 22. In the initial state, the first compression spring 24 is compressed under the action of the two electromagnets 21. There is a circuit connection between the electromagnet switch 22 and the two electromagnets 21. The vertical column 29 on the electromagnet switch 22 is in a vertical state and is in contact with the switch base 25 and the two circuit contacts 32 located on the displacement groove 27. At this time, the circuit is closed, and the two electromagnets 21 attract each other and move closer to each other. When the cam 6 rotates, the two second arc-shaped protrusions 8 compress the vertical column 29, and under the restriction of the limiting seat 26, it can only deflect in a direction away from the drive rod 2. At this time, the vertical column 29 drives the horizontal limiting baffle 30 to compress the second compression spring 31 and disconnect it from the circuit contact 32, thereby de-energizing the two electromagnets 21. This causes the magnetic force of the first compression spring 24 to disappear, and the first compression spring 24 rebounds, causing the fixed moving plate to move away from the drive rod 2, thereby causing the fixed clamping member 20 to loosen. Subsequently, when the cam 6 continues to rotate and the second arc protrusion 8 leaves the vertical column 29, the compressed second compression spring 31 generates a rebound force, causing the vertical column 29 to reset and contact the two circuit contacts 32, closing the circuit. The two electromagnets 21 generate magnetic force and return to the initial state.

[0030] The electromagnet switch 22 includes a switch base 25, which is fixed to a fixed connecting plate 19. A limit seat 26 is integrally formed on the upper end of the switch base 25. A displacement groove 27 is reserved on the limit seat 26. The upper part of the displacement groove 27 and the side away from the cam 6 are open. A horizontal column 28 that passes through the displacement groove 27 is rotatably connected to the limit seat 26. A vertical column 29 is fixed vertically and centrally on the horizontal column 28. A horizontal limit stop is provided in the displacement groove 27. The length of the horizontal limiting baffle 30 is matched with the width of the displacement groove 27, and the horizontal limiting baffle 30 is vertically fixed on the side of the horizontal column 28 away from the cam 6. A second compression spring 31 is fixedly connected between the horizontal limiting baffle 30 and the switch base 25. The vertical column 29 is located between the two second arc protrusions 8, and the vertical column 29 is in contact with the two second arc protrusions 8. Two circuit contacts 32 are reserved on the wall surface of the displacement groove 27 near the cam 6. Contact 32 is connected to two electromagnets 21 in a circuit, and the vertical column 29 is in contact with the two circuit contacts 32. In its natural state, the second compression spring 31 contacts the horizontal limiting baffle 30 and is compressed to a certain extent, causing the vertical column 29 connected to the horizontal limiting baffle 30 to tend to rotate towards the cam 6, thereby pressing the vertical column 29 onto the two circuit contacts 32 to form a circuit. When a force is applied to the vertical column 29 away from the cam 6, it causes the horizontal column 28 to rotate as well, at which point the circuit is broken, and the second compression spring 31 is further compressed by the horizontal limiting baffle 30. When the above force is removed, the second compression spring 31 generates a rebound force that acts on the horizontal limiting baffle 30, causing the vertical column 29 to rotate towards the cam 6, thereby resetting the electromagnet switch 22 and returning it to its natural state. The horizontal limiting baffle 30 prevents the horizontal column 28 from moving horizontally during rotation, ensuring good contact between the vertical column 29 and the circuit contacts 32 in its natural state.

[0031] Two coaxial through holes 33 are machined on the upper and lower end faces of the housing 1. The diameter of the two through holes 33 is larger than the diameter of the drive rod 2, and the drive rod 2 is placed inside the through holes 33. Several annular grooves 34 are reserved on the upper part of the drive rod 2. The several annular grooves 34 are arranged sequentially from top to bottom on the drive rod 2.

[0032] The movable clamping member 12 and the fixed clamping member 20 have the same structure, both including a vertical plate 35. Three clamping teeth 36 are machined on the side of the vertical plate 35 near the drive rod 2. The three clamping teeth 36 are all in the shape of a slight arc and are arranged alternately from top to bottom along the height direction of the vertical plate 35. The three clamping teeth 36 are adapted to the annular groove 34. A reinforcing rib 37 is fixed on the side of the vertical plate 35 away from the drive rod 2. The reinforcing rib 37 is fixed on the movable connecting plate 11 or the fixed connecting plate 19 respectively.

[0033] It should be noted that in an emergency, the control cam 6 can stop rotating to clamp the drive rod 2, thereby securing the control rod 4 in an emergency; or the power to the device can be turned off, and the rebound force generated by the two compressed limit springs 18 will cause the cam 6 to return to its initial position, releasing the moving clamp 12 and allowing the control rod 4 to be quickly inserted into the fuel assembly.

[0034] A control method for a cam-type control rod drive mechanism includes the following steps: 1. Assemble the cam-type control rod drive mechanism, set it at the center of the upper support plate of the pressure vessel, and conduct a pre-lifting test by powering it on to ensure that the cam-type control rod drive mechanism operates normally. 2. When the control rod 4 needs to rise, the drive motor is controlled to rotate, causing the cam 6 to rotate clockwise. This causes the first arc protrusion 7 to press against the trapezoidal wedge block 15 and compress the first connecting spring 14, thereby driving the movable clamping member 12 to clamp the drive rod 2 via the movable connecting plate 11. Simultaneously, the second arc protrusion 8 presses against the electromagnet switch 22, causing the vertical column 29 to rotate a certain angle away from the cam 6 and become closed, thereby releasing the first compression spring 24 and loosening the fixed clamping member 20. The movable clamping member 12 rises along with the cam 6 via the movable connecting plate 11 and... Compress the two limit springs 18 until the cam 6 rotates 90° to reach its highest point; just before reaching the highest point, the second arc protrusion 8 stops pressing the electromagnet switch 22 and springs back to the open state. The fixed connecting plate 19 moves towards the drive rod 2 under the action of the electromagnet 21, causing the fixed clamping member 20 to clamp the drive rod 2; then the first arc protrusion 7 stops pressing the trapezoidal wedge block 15, and the first connecting spring 14 springs back to its natural state while the moving clamping member 12 is released; the cam 6 continues to rotate and causes the moving connecting plate 11 to descend until it rotates 180° and returns to the initial state; 3. When the control rod 4 needs to descend, the cam-type control rod drive mechanism can descend by making the rotation direction of the cam 6 opposite to the rotation direction during the upward process in the initial state, as described above. 4. In an emergency, the control cam 6 can stop rotating to clamp the drive rod 2, thereby securing the control rod 4 in an emergency; or the cam-type control rod drive mechanism can be de-energized, and the electromagnet will stop working. The rebound force generated by the first compression spring will loosen the fixed clamping member, and the rebound force generated by the two compressed limit springs 18 will return the cam 6 to its initial position, loosening the moving clamping member 12 and allowing the control rod 4 to be quickly inserted into the fuel assembly.

[0035] Working principle: Several control rods 4 are clamped by clamping plates 3. When it is necessary to control the power of the fuel assembly, the clamping plates 3 move up and down under the drive of the drive rod 2, thereby controlling the power of the fuel assembly. Ascending process: Cam 6 rotates clockwise, causing the first arc protrusion 7 to press against the trapezoidal wedge block 15 and compress the first connecting spring 14, thereby driving the movable clamping member 12 to clamp the drive rod 2 via the movable connecting plate 11; simultaneously, the second arc protrusion 8 presses against the electromagnet switch 22, causing the vertical column 29 to rotate a certain angle away from cam 6 and become closed, thereby releasing the first compression spring 24 and loosening the fixed clamping member 20; the movable clamping member 12 continues to rise with cam 6 via the movable connecting plate 11 and compresses the two limit springs 1 8. Until the cam 6 rotates 90° to reach its highest point; when it is about to reach its highest point, the second arc protrusion 8 no longer presses the electromagnet switch 22, and it springs back to the open state. The fixed connecting plate 19 moves closer to the drive rod 2 under the action of the electromagnet 21, so that the fixed clamping member 20 clamps the drive rod 2; then the first arc protrusion 7 no longer presses the trapezoidal wedge block 15, and the first connecting spring 14 springs back to its natural state while the moving clamping member 12 is released; the cam 6 continues to rotate and the moving connecting plate 11 descends until it rotates to 180° and returns to the initial state; By following the above process, the cam-type control rod drive mechanism can be lowered by making the rotation direction of cam 6 opposite to the rotation direction during the upward process in the initial state.

[0036] The beneficial technical effects of this invention are as follows: The cam-type control rod drive mechanism of this invention includes a mechanism housing 1, a drive rod 2, a drive assembly, and a clamping assembly. The clamping assembly includes a movable clamping group and a fixed clamping group. The drive assembly operates to control the timing of the movable clamping group and the fixed clamping group clamping the drive rod 2. The drive assembly and the clamping assembly cooperate to enable the drive rod 2 to achieve lifting and lowering movement. The above structure not only eliminates the need to control multiple components to execute functions sequentially by controlling multiple sets of electromagnets, but also simplifies the control assembly and drive process, avoiding problems such as jamming and damage caused by improper coordination. Furthermore, the cam-type control rod drive mechanism improves the lifting efficiency of the control rod 4 and the response rate of the clamping assembly, thereby improving the motion continuity and drive efficiency of the cam-type control rod drive mechanism.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent changes made based on the description and drawings of the present invention are included within the scope of the present invention.

Claims

1. A cam-type control rod drive mechanism, disposed at the center of the upper support plate of a pressure vessel, characterized in that: The device includes a housing, within which a drive rod extends vertically through the housing. A clamping plate is connected to the lower end of the drive rod, and several control rods are mounted on the clamping plate. A drive assembly is mounted on the housing, and a clamping assembly is located inside the housing. The clamping assembly includes a movable clamping group and a fixed clamping group, both of which are in contact with the drive assembly. The movable clamping group is located above the fixed clamping group. The drive assembly operates to control the timing of the movable and fixed clamping groups clamping the drive rod. The drive assembly and the clamping assembly cooperate to enable the drive rod to move up and down.

2. The cam-type control rod drive mechanism according to claim 1, characterized in that: The drive assembly includes a drive motor disposed on the outer wall of the mechanism housing, a camshaft drivenly connected to the drive motor, and the camshaft extends through the outer wall of the mechanism housing into the mechanism housing. Two cams are fixedly connected to the camshaft and are spaced apart along the axial direction. Two first arc protrusions with the same structure are provided on the outer surface of one of the cams, and the movable clamping assembly contacts the two first arc protrusions. Two second arc protrusions with the same structure are provided on the inner surface of the other cam, and the fixed clamping assembly contacts the two second arc protrusions.

3. The cam-type control rod drive mechanism according to claim 1, characterized in that: Upper support plates are provided at the four corners inside the outer shell of the mechanism. All four upper support plates are at the same horizontal height. The movable clamping assembly is placed on the four upper support plates. Lower support plates are provided at the four corners inside the outer shell of the mechanism. All four lower support plates are at the same horizontal height. The fixed clamping assembly is placed on the four lower support plates.

4. The cam-type control rod drive mechanism according to claim 3, characterized in that: The movable clamping assembly includes a left clamping component and a right clamping component. The left and right clamping components have the same structure and are symmetrically arranged with the drive rod as the center. Both the left and right clamping components include movable connecting plates on two upper support plates on the same side. The movable connecting plates are located directly above the cam, and the distance between the movable connecting plates and the cam is less than the height of the cam. The bottom surface of the movable connecting plates is in contact with the cam. Movable clamping parts adapted to the drive rod are fixedly connected to the movable connecting plates. First spring connecting seats are fixedly connected to the movable connecting plates. First connecting springs are connected to both first spring connecting seats. The two movable clamping parts and the first connecting springs cooperate to clamp the drive rod. Trapezoidal wedges are fixedly connected to the movable connecting plates near the two first arc protrusions. The trapezoidal wedges are located between the two first arc protrusions and are in contact with the two first arc protrusions.

5. The cam-type control rod drive mechanism according to claim 4, characterized in that: Spring limit rods are vertically fixed on both movable connecting plates, and limit springs are fitted on the spring limit rods. The limit springs are located between the inner wall of the mechanism housing and the movable connecting plate. Through holes corresponding to the two spring limit rods are provided on the upper end face of the mechanism housing.

6. The cam-type control rod drive mechanism according to claim 3, characterized in that: The fixed clamping assembly includes a left clamping component and a right clamping component. The left and right clamping components have the same structure and are symmetrically arranged with the drive rod as the center. Both the left and right clamping components include fixed connecting plates on two lower support plates on the same side. Fixed clamping parts adapted to the drive rod are fixedly connected to the fixed connecting plates. Electromagnets are fixedly connected to the fixed connecting plates. The magnetic poles of the two electromagnets are opposite to each other on their opposite sides. The two fixed clamping parts and the two electromagnets work together to clamp the drive rod. Electromagnetic switches are fixedly connected to the fixed connecting plates near the two second arc protrusions. Both electromagnets are connected to the electromagnet switch circuit. The electromagnet switches are located between and in contact with the two second arc protrusions. Second spring connecting seats are fixedly connected to the fixed connecting plates. A first compression spring is connected to both second spring connecting seats.

7. The cam-type control rod drive mechanism according to claim 6, characterized in that: The electromagnet switch includes a switch base fixed to a fixed connecting plate, a limit seat fixedly connected to the upper end of the switch base, a displacement groove provided on the limit seat, the opening direction of the displacement groove being away from the cam, a horizontal column rotatably connected to the limit seat and passing through the displacement groove, a vertical column fixedly fixed in the center of the horizontal column, the vertical column being located between and in contact with the two second arc protrusions, a horizontal limit baffle fixed to the horizontal column being provided in the displacement groove, the horizontal limit baffle being located on the side of the horizontal column away from the cam, a second compression spring being fixedly connected between the horizontal limit baffle and the switch base, two circuit contacts being provided on the wall surface of the displacement groove near the cam, the two circuit contacts being connected to two electromagnet circuits, and the vertical column being in contact with the two circuit contacts.

8. The cam-type control rod drive mechanism according to claim 1, characterized in that: A coaxial through hole is provided on both the upper and lower end faces of the mechanism housing. The drive rod is placed inside the through hole, and several annular grooves are arranged at intervals from top to bottom on the upper part of the drive rod.

9. The cam-type control rod drive mechanism according to claim 8, characterized in that: The movable clamping component and the fixed clamping component have the same structure, both including a vertical plate. Several clamping teeth that are adapted to the annular groove are provided on the side of the vertical plate near the drive rod. A reinforcing rib plate that is connected to the movable connecting plate or the fixed connecting plate is fixed on the side of the vertical plate away from the drive rod.

10. A control method for a cam-type control rod drive mechanism according to any one of claims 1-9, characterized in that: Includes the following steps: S1. Assemble the cam-type control rod drive mechanism, set it at the center of the upper support plate of the pressure vessel, and conduct a pre-lifting test by powering on it to ensure that the cam-type control rod drive mechanism operates normally. S2. When the control rod needs to rise, the drive motor is activated, causing the cam to rotate clockwise. This causes the first arc-shaped protrusion to press against the trapezoidal wedge and compress the first connecting spring, thereby moving the movable clamping member to hold the drive rod via the movable connecting plate. Simultaneously, the second arc-shaped protrusion presses against the electromagnet switch, causing the vertical column to rotate away from the cam by a certain angle and become closed, thus releasing the first compression spring and loosening the fixed clamping member. The movable clamping member rises along with the cam via the movable connecting plate, compressing the two limit springs until the cam rotates 90° to reach its highest point. Just before reaching the highest point, the second arc-shaped protrusion stops pressing against the electromagnet switch and springs back to the open state. The fixed connecting plate moves towards the drive rod under the action of the electromagnet, causing the fixed clamping member to hold the drive rod. Subsequently, the first arc-shaped protrusion stops pressing against the trapezoidal wedge, and the first connecting spring springs back to its natural state, simultaneously releasing the movable clamping member. The cam continues to rotate and causes the movable connecting plate to descend until it rotates 180°, returning to the initial state. S3. When the control rod needs to descend, the cam-type control rod drive mechanism can descend by making the cam rotation direction opposite to the rotation direction during the ascent process in the initial state, as described above. S4. In an emergency, the control cam can stop rotating to clamp the drive rod, thereby securing the control rod in an emergency. Alternatively, the cam-type control rod drive mechanism can be de-energized, and the electromagnet will stop functioning. The rebound force generated by the first compression spring will loosen the fixed clamping component. The rebound force generated by the two compressed limit springs will return the cam to its initial position, loosening the moving clamping component and allowing the control rod to be quickly inserted into the fuel assembly.

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