Hydraulic clamp for processing nuclear fuel assembly tube seat

Abstract

The utility model relates to the field of nuclear fuel assembly manufacturing, in particular to a hydraulic clamp for nuclear fuel assembly tube base machining. The hydraulic clamp comprises a clamp base body, wherein the center of the clamp base body is a clamping station; the air tightness detection system matching device is installed in the clamp base body and connected to the air tightness detection supporting block through a pipeline. The clamp unit comprises a positioning pin, an air tightness detection supporting block, a hydraulic clamp and an air tap. The two positioning pins are arranged at two opposite angles of the clamping station; the air tightness detection supporting block is provided with an air tightness detection hole. The two air tightness detection supporting blocks are arranged at the other two opposite angles of the clamping station; after the air tightness detection hole is tightly attached to the workpiece to be machined, an air path of the air tightness detection system is closed; the hydraulic clamps are arranged on the four side faces of the clamping station and are symmetrically distributed, and the air nozzles are located above or below the air tightness detection supporting blocks; and the control mechanism realizes information interaction with the air tightness detection system and controls the hydraulic clamp to act. The positioning device is matched with a manipulator to work, so that automatic production is realized, the positioning accuracy is high, and the processing time is shortened.

Description

Technical Field

[0001] This utility model relates to the field of nuclear fuel assembly manufacturing, and in particular to a hydraulic clamp for machining nuclear fuel assembly tube seats. Background Technology

[0002] The fuel assembly includes a tube seat made of 304 stainless steel, such as Figure 1 As shown. The upper and lower tube sockets have complex structures, each consisting of an upper and a lower tube socket. The processing methods for the tube sockets differ slightly depending on the fuel assembly. For annular fuel assemblies, the upper and lower tube sockets are machined in two parts, welded together, and then precision-machined. For AP1000 and CAP1400 fuel assemblies, the upper tube socket is integrally cast and then machined to achieve high-precision dimensions. The lower tube socket is partly cast and partly machined from sheet metal, then welded together and finally machined to achieve high-precision dimensions. For AFA 3G fuel assemblies, the upper tube socket is formed by electron beam welding of a frame plate and a surrounding plate, while the lower tube socket is formed from sheet metal through four machining processes.

[0003] In general, the fittings for various fuel assemblies require high precision and involve long machining times. Existing machining fixtures are manual, requiring manual loading and unloading. Hexagonal clamps are used to hold the fixture in place, and after installation, manual alignment is necessary to ensure the workpiece's position coincides with the coordinate system. This current machining technology results in low processing efficiency and cannot meet production capacity requirements. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a hydraulic fixture for machining nuclear fuel assembly tube seats, which, in conjunction with a robotic arm, enables automated production, has high positioning accuracy, and shortens processing time.

[0005] This utility model provides a hydraulic fixture for machining nuclear fuel assembly tube seats, including: a fixture base, a fixture unit, an airtightness detection system, and a control mechanism;

[0006] The fixture base has a clamping station at its center; the air tightness testing system and its supporting devices are installed inside the fixture base and connected to the air tightness testing support block via pipelines.

[0007] The clamping unit includes a positioning pin, an airtightness testing support block, a hydraulic clamp, and an air nozzle;

[0008] Two locating pins are set at two opposite corners of the clamping station; the airtightness testing support block is provided with an airtightness testing hole;

[0009] Two airtightness testing support blocks are set at the other two opposite corners of the clamping station;

[0010] After the air tightness test hole is tightly fitted to the workpiece to be processed, the air passage of the air tightness test system is closed.

[0011] The hydraulic clamps are symmetrically distributed on the four sides of the clamping station.

[0012] The air nozzle is located above or below the airtightness testing support block;

[0013] The control mechanism interacts with the airtightness testing system and controls the hydraulic clamp's movement.

[0014] In this specific embodiment, six hydraulic clamps are arranged on the four sides of the clamping station in a symmetrical distribution.

[0015] In this specific embodiment, a hydraulic cylinder is pre-embedded inside the fixture base. The hydraulic clamp is connected to the hydraulic cylinder, which is controlled by a solenoid valve. When the hydraulic cylinder moves, it drives the hydraulic clamp to move, thereby achieving clamping and releasing.

[0016] In this specific embodiment, the bottom surface of the fixture base is connected to the machine tool worktable, a fixture unit is installed on it, and a fixture unit is installed on each of the three surrounding sides.

[0017] In a specific embodiment of this example, the positioning pin is provided with an airtightness detection hole.

[0018] In this specific embodiment, an air nozzle is also provided above or below the positioning pin.

[0019] In this specific embodiment, the airtightness testing support block is a cylinder.

[0020] In this specific embodiment, an energy storage mechanism is also included. The energy storage mechanism is installed on the clamp base to provide pressure replenishment for the hydraulic clamp.

[0021] Compared with the prior art, the hydraulic clamp for machining nuclear fuel assembly tube seats of this utility model has the following advantages:

[0022] Beneficial effects:

[0023] (1) Equipped with airtightness detection to ensure that the automatic feeding system is installed in place;

[0024] (2) The hydraulic clamp has an automatic positioning function. The hydraulic clamp ensures uniform clamping force for each installation, avoiding the problem of uneven force on the workpiece causing dimensional changes that occurs when using manual clamps.

[0025] (3) It can be used in conjunction with a robot to achieve automated workpiece clamping and automated pipe seat processing. Attached Figure Description

[0026] Figure 1 This diagram shows the structure of the tube seat.

[0027] Figure 2 This diagram shows the structure of the tube seat clamp.

[0028] In the figure, 1. Fixture base; 2. Positioning pin; 3. Hydraulic clamp; 4. Air tightness test support block; 5. Air nozzle; 6. Energy storage mechanism; 7. Pipe seat. Detailed Implementation

[0029] To further understand this utility model, the embodiments of this utility model are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of this utility model, and not for limiting this utility model.

[0030] The hydraulic clamp described in this utility model can be used to clamp the tube seat structure of various types of fuel assembly. The fuel assembly tube seat structure mainly features planes, cavities, and stepped holes. Based on its structural characteristics, the dimensions and positioning methods of the hydraulic clamp's locating pins are studied to ensure the stability and reliability of the hydraulic clamp. During the finishing process, accurate positioning is ensured; pre-machined holes are typically used as locating holes. To prevent the locating pins from scratching the inner wall of the holes, the hydraulic clamp uses clearance fits throughout. Considering the ease of use of the hydraulic clamp, the positioning and clamping method should be a scheme with a self-aligning method to ensure the consistency of the hydraulic clamp's center and avoid the manual alignment work of existing technologies. To prepare for subsequent process optimization of the tube seat machining process, the hydraulic clamp should be designed with good rigidity to ensure that the clamping force can meet the requirements of subsequent process optimization. The hydraulic fixture is also equipped with an airtightness detection function, which can give a signal to the robot arm. If the clamping is not in place or there is a problem with the blank, it can feed back to the machine tool control mechanism to stop the subsequent processing action and call the robot arm to re-clamp. If the airtightness test meets the requirements, the hydraulic fixture will perform hydraulic clamping and processing. After processing is completed, the fixture will be automatically released and the robot arm will automatically unload the blank.

[0031] An embodiment of this utility model discloses a hydraulic fixture for machining nuclear fuel assembly tube seats, such as... Figure 2 As shown, it includes: a fixture base 1, a fixture unit, an airtightness detection system, and a control mechanism;

[0032] The fixture base 1 has a clamping station at its center; the air tightness testing system is installed inside the fixture base 1 and is connected to the air tightness testing support block 4 through a pipeline, which is the existing structure.

[0033] The clamping unit includes a positioning pin 2, an airtightness testing support block 4, a hydraulic clamp 3, an air nozzle 5, and an energy storage mechanism 6.

[0034] Two locating pins 2 are set at two opposite corners of the clamping station to position the tube seat workpiece.

[0035] The locating pin 2 is positioned relative to the other two diagonals of the reference hole of the tube seat, serving to support the tube seat workpiece. The locating pin 2 is symmetrically distributed, which can ensure positioning accuracy and will not cause the workpiece to shake during machining, thus greatly reducing the displacement in the XY direction.

[0036] The positioning pin 2 is provided with an airtightness detection hole;

[0037] In actual working environment, after the air tightness test hole on the positioning pin 2 is tightly fitted with the tube seat workpiece, the air tightness test system air circuit is closed, and the tube seat tool is installed in place.

[0038] The air tightness testing support block 4 is a cylinder, and two air tightness testing support blocks 4 are set at the other two opposite corners of the clamping station; the air tightness testing support block 4 is provided with an air tightness testing hole, which is connected to the air tightness testing system.

[0039] Only after the lower tube seat and support block are fully in contact and the airtightness test hole is closed, will the pressure of the airtightness test system change. This will trigger the pressure sensor in the system to activate and send a signal to the control mechanism, allowing the system to continue operating.

[0040] The positioning pin and the airtightness testing support block can function simultaneously or not. When only one is functioning, the other remains closed.

[0041] A hydraulic cylinder is pre-embedded inside the fixture base 1. The hydraulic clamp 3 is connected to the hydraulic cylinder. The hydraulic cylinder is controlled by a solenoid valve. When the hydraulic cylinder moves, it drives the hydraulic clamp 3 to move, thereby achieving clamping and releasing.

[0042] Six hydraulic clamps 3 are symmetrically distributed on the four sides of the clamping station.

[0043] Since the hydraulic cylinder pressure is set to be consistent, the hydraulic clamps 3 move in a consistent manner. Furthermore, because the hydraulic clamps are symmetrically distributed, the clamping force on each surface is consistent, thus the fixture has a self-aligning function.

[0044] Nozzle 5 is used to blow away debris from the surface of the locating pins or airtightness testing support blocks during the processing.

[0045] The air nozzle 5 is located above or below the positioning pin 2; or

[0046] An air nozzle 5 is also provided above or below the airtightness testing support block 4.

[0047] The energy storage mechanism 6 is installed on the clamp base 1 to provide pressure replenishment for the hydraulic clamp 3.

[0048] Since the hydraulic clamp 3 uses hydraulic power, the hydraulic pressure is disconnected after clamping the workpiece. In order to maintain a stable pressure in the pipe seat tooling during the processing, an energy storage mechanism 6 is added to store a certain amount of positive pressure hydraulic oil for pressure replenishment.

[0049] The bottom surface of the fixture base 1 is connected to the machine tool worktable, a fixture unit is installed on it, and a fixture unit is installed on each of the three surrounding sides.

[0050] When the internal pressure of the airtightness detection system changes, the pressure sensor sends a signal to the control mechanism. Once the airtightness detection is passed, the solenoid valve is energized and engaged, the oil circuit is switched, the hydraulic cylinder is activated, and the hydraulic clamp 3 connected to it is activated to begin the clamping action.

[0051] The control mechanism interacts with the airtightness detection system. The pressure sensor sends a signal to the control mechanism. If the airtightness test is passed, the control mechanism energizes the solenoid valve, switches the oil circuit, and activates the hydraulic cylinder, which in turn moves the hydraulic clamp connected to it. If the airtightness test fails, no action is taken.

[0052] The control mechanism also controls the air nozzle 5 to perform automatic purging.

[0053] The specific operation process of the hydraulic fixture for machining nuclear fuel assembly tube seats of this utility model is as follows:

[0054] Step 1: Before starting automated processing, a pre-operation inspection is carried out manually to check the appearance and integrity of the hydraulic clamps. Ensure that there are no debris on the surface of the support block and the locating pin, and that the chamfer of the locating pin is rounded and free of defects such as dents and scratches, so as to ensure that the workpiece will not be squeezed or scratched during the clamping process.

[0055] Step 2: Start the automated machining program. The robotic arm picks up the workpiece and aligns the S-hole with the S-hole positioning pin on the hydraulic clamp. The workpiece is slowly pushed in and pressed against the airtightness testing support block. The airtightness testing hole is now closed, and the internal pressure of the airtightness system changes. The pressure sensor sends a signal to the machine tool, and the airtightness test is passed. The solenoid valve is energized and engages, the oil circuit is switched, and the hydraulic cylinder actuates, driving the hydraulic clamps connected to it to move and begin the clamping action. Starting from the 12 o'clock direction, two hydraulic clamps on each side form a group and clamp counterclockwise. Since the preset pressure and model of each hydraulic cylinder are completely consistent, the displacement distance of the hydraulic clamps is consistent during the clamping action. Therefore, the centering and consistency of the clamping process are guaranteed, achieving a self-positioning function.

[0056] Step 3: Workpiece machining. After the workpiece is clamped, the control mechanism rotates the clamped hydraulic fixture to the machining area and calls the machining program to perform the machining.

[0057] Step 4: Remove the workpiece. After processing, the control mechanism automatically rotates the hydraulic clamp with the workpiece to the non-processing area, automatically starts the release program, the solenoid valve actuates, the oil circuit changes, the state changes from engaged to released, and then the hydraulic cylinder actuates, pushing the hydraulic clamp to move. Starting from the 12 o'clock direction, two hydraulic clamps on each side form a group, and the release action is performed counterclockwise. After the release action is completed, the robot slowly and evenly pulls the workpiece outward; the purging program is run, the solenoid valve is energized, the air circuit is connected, and compressed air is sprayed from the air nozzle to purge the airtightness inspection support block of the clamp, and the cycle continues to process the next tube seat.

[0058] The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principle of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

[0059] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A hydraulic fixture for machining nuclear fuel assembly tube seats, characterized in that, include: Fixture base, fixture unit, airtightness testing system and control mechanism; The fixture base has a clamping station at its center; the air tightness testing system and its supporting devices are installed inside the fixture base and connected to the air tightness testing support block via pipelines. The clamping unit includes a positioning pin, an airtightness testing support block, a hydraulic clamp, and an air nozzle; Two locating pins are set at two opposite corners of the clamping station; the airtightness testing support block is provided with an airtightness testing hole; Two airtightness testing support blocks are set at the other two opposite corners of the clamping station; After the air tightness test hole is tightly fitted to the workpiece to be processed, the air passage of the air tightness test system is closed. The hydraulic clamps are symmetrically distributed on the four sides of the clamping station. The air nozzle is located above or below the airtightness testing support block; The control mechanism interacts with the airtightness testing system and controls the hydraulic clamp's movement.

2. The hydraulic fixture for machining nuclear fuel assembly tube seats according to claim 1, characterized in that, It includes six hydraulic clamps, which are symmetrically distributed on the four sides of the clamping station.

3. The hydraulic fixture for machining nuclear fuel assembly tube seats according to claim 2, characterized in that, A hydraulic cylinder is pre-embedded inside the fixture base. The hydraulic clamp is connected to the hydraulic cylinder, which is controlled by a solenoid valve. When the hydraulic cylinder moves, it drives the hydraulic clamp to move, thereby achieving clamping and releasing.

4. The hydraulic fixture for machining nuclear fuel assembly tube seats according to claim 1, characterized in that, The bottom surface of the fixture base is connected to the machine tool worktable, a fixture unit is installed on it, and a fixture unit is installed on each of the three surrounding sides.

5. The hydraulic fixture for machining nuclear fuel assembly tube seats according to claim 1, characterized in that, The positioning pin is provided with an airtightness detection hole.

6. The hydraulic fixture for machining nuclear fuel assembly tube seats according to claim 5, characterized in that, An air nozzle is also provided above or below the positioning pin.

7. The hydraulic fixture for machining nuclear fuel assembly tube seats according to claim 1, characterized in that, The airtightness testing support block is a cylinder.

8. The hydraulic fixture for machining nuclear fuel assembly tube seats according to claim 1, characterized in that, It also includes an energy storage mechanism, which is mounted on the clamp base to provide pressure replenishment for the hydraulic clamp.

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