A high-precision valve body turning fixture

Abstract

This utility model provides a high-precision valve body turning fixture, belonging to the field of machining fixture technology. The high-precision valve body turning fixture includes a base with a positioning base at its center. The base has multiple sets of through holes and stepped countersunk holes. A four-way synchronous clamping mechanism is provided on the upper surface of the base, including opposing first radial clamping blocks, second radial clamping blocks, and opposing third and fourth radial clamping blocks. The first and second radial clamping blocks clamp the valve body by adjusting a fine-tuning screw; the third and fourth radial clamping blocks clamp the valve body by tightening clamping bolts. The base is a square substrate with chamfered edges at its four corners. This utility model solves the problems of inconsistent positioning references, uneven clamping force distribution, poor adaptability, and low adjustment accuracy, which lead to a high rate of cumulative error exceeding tolerances in valve body machining and make it difficult to meet high-precision machining requirements.

Description

Technical Field

[0001] This utility model belongs to the field of machining fixture technology, specifically, it relates to a high-precision valve body turning fixture. Background Technology

[0002] In petrochemical pipeline systems, the valve body of a DN80 150 / 300 lb top-mount valve requires step-by-step machining via turning and milling, with stringent precision requirements. Turning must ensure end-face concentricity ≤0.03mm, while milling requires controlling the flange's evenly distributed groove angle tolerance to ±0.5°. Currently, traditional valve body turning fixtures often employ a decentralized positioning structure, where the positioning datum frequently changes with clamping components. For example, turning might use one end face of the valve body as the datum, while milling switches to the flange's outer diameter. This inconsistency in datum can lead to cumulative errors. Furthermore, traditional fixtures often use unidirectional or bidirectional clamping, resulting in uneven clamping force distribution that can cause valve body misalignment or deformation. Additionally, the clamping components are often fixed structures, making them unsuitable for different valve body specifications. Changing the fixture necessitates readjusting the positioning, further increasing the risk of datum deviation. In addition, the clamping and adjusting components of traditional tooling have low precision and lack fine adjustment mechanisms, making it difficult to accurately control the valve body positioning. These factors together result in a cumulative error deviation rate of up to 42% for traditional tooling, which cannot meet the requirements of high-precision machining. In summary, existing technologies suffer from problems such as inconsistent positioning references, uneven clamping force distribution, poor adaptability, and low adjustment accuracy, resulting in a high rate of cumulative error exceeding tolerances in valve body machining and making it difficult to meet the requirements of high-precision machining. Utility Model Content

[0003] In view of this, the present invention provides a high-precision valve body turning fixture, which can solve the problems of inconsistent positioning references, uneven clamping force distribution, poor adaptability and low adjustment accuracy, resulting in a high rate of cumulative error exceeding tolerance in valve body machining and making it difficult to meet the requirements of high-precision machining.

[0004] This utility model is implemented as follows: This utility model provides a high-precision valve body turning fixture, which includes a base, a positioning base at the center of the base, and multiple sets of through holes and stepped countersunk holes on the base. A four-way synchronous clamping mechanism is provided on the upper surface of the base. The four-way synchronous clamping mechanism includes a first radial clamping block, a second radial clamping block, a third radial clamping block, and a fourth radial clamping block facing each other. The first radial clamping block and the second radial clamping block clamp the valve body by adjusting the fine-tuning screw. The third radial clamping block and the fourth radial clamping block clamp the valve body by tightening the clamping bolt.

[0005] The technical advantages of this high-precision valve body turning fixture are as follows: The positioning base at the center of the base provides a positioning reference for the valve body; multiple through holes and stepped countersunk holes on the base provide flexible adaptability for the installation of fixture components; the four-way synchronous clamping mechanism clamps the valve body from four opposing directions, which, compared to traditional single-way or double-way clamping, avoids displacement or deformation of the valve body due to uneven force, ensuring that the concentricity of the valve body end face is stably controlled within ≤0.03mm during turning; the fine-tuning screw can precisely control the clamping force, avoiding excessive clamping and damage to the valve body; the clamping bolts provide stable locking force, preventing the valve body from loosening during machining.

[0006] Based on the above technical solution, the high-precision valve body turning fixture of this utility model can be further improved as follows: The base is a square substrate with chamfered edges at the four corners.

[0007] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: compared with round or irregular bases, square base plates have a more stable support structure, which can reduce the installation offset of the fixture on the processing equipment; the chamfering of the four corners can avoid sharp edges and improve operational safety.

[0008] Furthermore, the inner sides of the first radial clamping block and the second radial clamping block are provided with reinforcing ribs, which are fixedly connected to the upper surface of the base by bolts.

[0009] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the reinforcing ribs can enhance the structural rigidity of the first and second radial clamping blocks, prevent the clamping blocks from bending and deforming due to force during clamping, ensure that the clamping force is stably transmitted to the valve body, prevent the valve body positioning offset caused by the deformation of the clamping blocks, and ensure the concentricity accuracy of the end faces; the reinforcing ribs are fixed to the base with bolts, further enhancing the connection stability between the clamping blocks and the base, preventing the clamping blocks from loosening during long-term use, reducing the positioning error caused by the connection gap, and facilitating the disassembly, maintenance and replacement of the clamping blocks in the later stage.

[0010] Furthermore, the first radial clamping block is provided with a threaded hole, and the fine-tuning screw is movably connected to the first radial clamping block through the threaded hole. The fine-tuning screw is provided with an abutment seat at one end near the inner side of the first radial clamping block.

[0011] The beneficial effects of adopting the above-mentioned improved scheme are as follows: Fine adjustment via threaded drive is achieved through the cooperation of the threaded hole and the fine-tuning screw. Operators can precisely control the feed amount of the abutment seat by rotating the fine-tuning screw. Compared with traditional direct clamping, this allows for more accurate positioning of the valve body at the reference position, reducing positioning deviation. Furthermore, the abutment seat increases the contact area between the fine-tuning screw and the valve body, while also dispersing the clamping force, ensuring that the valve body surface is not damaged. The increased contact area also improves positioning stability and reduces offset caused by machining vibration.

[0012] Furthermore, a slot is provided at the top of the second radial clamping block; the connecting part of the contact plate is inserted into the slot and locked at its top by a locking bolt, and the contact plate abuts against the valve body through the contact part.

[0013] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the detachable contact structure is achieved by the insertion and cooperation of the slot and the contact plate, and the appropriate contact plate can be replaced according to different valve body specifications, improving the versatility of the fixture, eliminating the need to design fixtures separately for different valve bodies, and reducing costs; the locking bolt ensures the connection stability between the contact plate and the second clamping block, avoiding positioning offset caused by loosening of the plate during processing; at the same time, the contact part of the contact plate can be customized according to the shape of the valve body, such as an arc-shaped contact surface, improving the fit with the valve body and further ensuring positioning accuracy.

[0014] Furthermore, threaded holes are provided on both sides of the second radial clamping block near the slot, and a set of fine-tuning screws are respectively provided in the threaded holes. The inner end of the fine-tuning screws abuts against the contact plate.

[0015] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the contact plate is positioned and adjusted laterally by the fine-tuning screws on both sides, and together with the fine-tuning screw of the first clamping block, a two-way fine-tuning system is formed, which can accurately correct the positional deviation between the contact plate and the valve body, ensure that the center of the valve body and the center of the positioning base are completely coincident, and further improve the concentricity accuracy of the end face; the fine-tuning screws symmetrically arranged on both sides can balance the force on the contact plate, avoid the plate tilting caused by unilateral adjustment, ensure that the contact plate and the valve body keep the contact surface flat, and reduce the positioning error caused by the plate tilting.

[0016] Furthermore, the third radial clamping block includes a lower clamping clamp and an upper clamping clamp. A clamping groove is provided between the lower clamping clamp and the upper clamping clamp. The lower clamping clamp and the upper clamping clamp are movably hinged on one side and fixedly connected on the other side by clamping bolts.

[0017] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the opening and closing adjustment of the clamping groove is achieved by hinged one side of the upper clamp and fixed by bolts on the other side, which facilitates the quick clamping and disassembly of the valve body and improves the operating efficiency compared with the traditional integral clamping block; at the same time, the clamping groove can be designed according to the radial dimension of the valve body to ensure a tight fit between the clamping block and the valve body and reduce the positioning gap; the hinged structure can ensure the stability of the upper clamp when opening and closing, avoid the position displacement of the clamping block during the opening and closing process, and ensure the consistency of the positioning reference.

[0018] Furthermore, the bottom end of the clamping bolt is hinged to the lower clamp, and the upper clamp has a through hole, through which the clamping bolt passes and is locked in place by a nut.

[0019] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the hinge structure between the clamping bolt and the lower clamp can prevent the clamping bolt from rotating and shifting during the locking process, thereby improving the transmission efficiency of the locking force; at the same time, the through bolt design can provide stronger locking force and prevent the valve body from loosening due to cutting force during the machining process.

[0020] Furthermore, the fourth radial clamping block structure is the same as the third radial clamping block structure, and is arranged opposite to the third radial clamping block. The bottom clamping block is fixedly connected to the base by bolts.

[0021] The beneficial effects of adopting the above-mentioned improved scheme are as follows: by symmetrically setting the fourth radial clamp and the third radial clamp, and cooperating with the opposing layout of the first radial and second radial clamps, a four-way symmetrical clamping is formed, which ensures that the clamping force on the valve body is evenly distributed in four directions, avoids the valve body from shifting or deforming due to force on one side, ensures the stability of the positioning reference, and improves the control accuracy of end face concentricity and flange groove angle tolerance.

[0022] Furthermore, the stepped countersunk hole specifications are Φ13-Φ19 to be compatible with M12-M16 bolts.

[0023] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the compatible design of the stepped countersunk hole allows the base to be adapted to bolts of different specifications, and when installing the fixture components, the appropriate bolt specifications can be selected according to the stress requirements of the components.

[0024] Compared with existing technologies, the advantages of this high-precision valve body turning fixture are as follows: A unified positioning reference is provided by the positioning base at the center of the base, and a four-way synchronous clamping mechanism avoids deviations caused by dispersed positioning references and uneven force. Fine positioning is achieved through the micro-adjustment screws of the first and second radial clamping blocks, while the hinged clamping structure of the third and fourth radial clamping blocks enhances stability. Simultaneously, the square base, reinforcing ribs, and compatible stepped countersunk holes improve the fixture's rigidity, adaptability, and installation flexibility. The overall solution ensures that the concentricity of the valve body turning end face is stably controlled within ≤0.03mm, significantly reducing the cumulative error rate. It is also adaptable to different valve body specifications, such as 150 / 300 lbs, balancing precision and versatility, and improving processing efficiency and product qualification rate. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1This is a schematic diagram of a high-precision valve body turning fixture. Figure 2 This is a schematic diagram showing the location of the openings in the base. Figure 3 This is a schematic diagram of the first radial clamping block; Figure 4 This is a schematic diagram of the second radial clamping block; Figure 5 This is a schematic diagram of the top of the second radial clamping block; Figure 6 This is a schematic diagram of the third radial clamping block; Figure 7 This is a schematic diagram of the fourth radial clamping block; The attached diagram lists the components represented by each number as follows: 10. Base; 11. Positioning base; 12. Through hole; 13. Stepped countersunk hole; 14. Four-way synchronous clamping mechanism; 15. First radial clamping block; 16. Second radial clamping block; 17. Third radial clamping block; 18. Fourth radial clamping block; 19. Fine-tuning screw; 20. Clamping bolt; 21. Reinforcing rib; 22. Abutment seat; 23. Contact plate; 24. Lower clamp; 25. Upper clamp; 26. Clamping groove; 27. Clamping slot; 28. Locking bolt. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0028] like Figure 1-7 The image shows an embodiment of a high-precision valve body turning fixture provided by this utility model. In this embodiment, a base is included, a positioning base is provided at the center of the base, and multiple sets of through holes and stepped countersunk holes are provided on the base. A four-way synchronous clamping mechanism is provided on the upper surface of the base. The four-way synchronous clamping mechanism includes a first radial clamping block, a second radial clamping block, and a third radial clamping block and a fourth radial clamping block facing each other. The first radial clamping block and the second radial clamping block clamp the valve body by adjusting the fine-tuning screw; the third radial clamping block and the fourth radial clamping block clamp the valve body by tightening the clamping bolt.

[0029] In the above technical solution, the base is a square substrate, and the four corners of the square substrate are chamfered.

[0030] Furthermore, in the above technical solution, the inner sides of the first radial clamping block and the second radial clamping block are provided with reinforcing ribs, and the reinforcing ribs are fixedly connected to the upper surface of the base by bolts.

[0031] Furthermore, in the above technical solution, a threaded hole is provided on the first radial clamping block, and the fine-tuning screw is movably connected to the first radial clamping block through the threaded hole. An abutment seat is provided at one end of the fine-tuning screw near the inner side of the first radial clamping block.

[0032] Furthermore, in the above technical solution, a slot is provided at the top of the second radial clamping block; the connecting part of the contact plate is inserted into the slot and locked at its top by a locking bolt, and the contact plate abuts against the valve body through the contact part.

[0033] Furthermore, in the above technical solution, threaded holes are provided on both sides of the second radial clamping block near the slot, and a set of fine-tuning screws are respectively provided in the threaded holes, where the inner end of the fine-tuning screws abuts against the contact plate.

[0034] Furthermore, in the above technical solution, the third radial clamping block includes a lower clamping block and an upper clamping block. A clamping groove is provided between the lower clamping block and the upper clamping block. The lower clamping block and the upper clamping block are movably hinged on one side and fixedly connected on the other side by clamping bolts.

[0035] Furthermore, in the above technical solution, the bottom end of the clamping bolt is movably hinged to the lower clamp, and the upper clamp has a through hole, through which the clamping bolt passes and is locked and fixed by a nut.

[0036] Furthermore, in the above technical solution, the fourth radial clamping block structure is the same as the third radial clamping block structure, and is arranged opposite to the third radial clamping block. The bottom clamping block is fixedly connected to the base by bolts.

[0037] Furthermore, in the above technical solution, the stepped countersunk hole specifications are Φ13-Φ19 to be compatible with M12-M16 bolts.

[0038] The following is a specific embodiment: The fixture base adopts a square base plate of 320mm×260mm×24mm, and the base plate material is 45# steel; the four corners of the base plate are machined with 20mm×45° chamfers. Four sets of stepped countersunk holes with specifications of Φ13-Φ19 are opened on the square base plate, distributed near the four corners of the base plate, which are compatible with M12-M16 bolts, and are used to realize the fixed assembly of the fixture with the worktable of the processing equipment, and the various clamping components with the base plate, to adapt to the force requirements of different components (e.g., M16 bolts are used to fix the clamping mechanism, and M12 bolts are used to fix the auxiliary components). A positioning base with a diameter adapted to the center hole of the DN80 valve body is welded to the center of the base plate. The coaxiality error between the axis of the positioning base and the geometric center of the base plate is ≤0.005mm, providing a unified positioning reference for the valve body. A four-way synchronous clamping mechanism is assembled on the upper surface of the base plate, and its clamping range is designed to be Φ80-Φ220mm, which can cover the processing requirements of valve bodies with a diameter of DN80 and larger. The first and second radial clamping blocks are both equipped with reinforcing ribs on their inner sides, which are fixed to the upper surface of the base plate by M14 bolts. The first radial clamping block has threaded holes that are compatible with M42 fine-tuning screws. The tolerance of the fine-tuning screw is controlled within ±0.015mm. A circular abutment seat is installed at the end of the screw closest to the valve body. By rotating the fine-tuning screw, the screw can be tightened against the center hole of the valve body to achieve precise longitudinal positioning. The second radial clamping block has a slot at the top, into which a contact plate is inserted. The top of the contact plate is locked by a locking bolt. M42 fine-tuning screws are also installed in the threaded holes on both sides of the slot, which can be used to tighten the contact plate laterally to further correct the position of the valve body. The third and fourth radial clamping blocks are arranged opposite each other and have the same structure, both including a lower clamping block and an upper clamping block. The lower clamping block is fixed to the base plate by an M16 bolt, and a clamping groove is formed between the lower and upper clamping blocks. One side is hinged to the lower clamping block, and the other side is fixed by a clamping bolt. The bottom end of the clamping bolt is hinged to the lower clamping block, and a through hole is opened at the corresponding position on the upper clamping block. The clamping bolt passes through the through hole and is locked by a nut. When locking, the torque can be controlled by a torque wrench (set to 80-100 N·m) to ensure stable clamping force and no damage to the valve body. In use, the DN80 valve body is placed on the positioning base. The fine-tuning screw of the four-way clamping mechanism works in conjunction with the clamping bolt to achieve offset positioning of the valve body, meeting the accuracy requirement of concentricity of the machined end face ≤0.03mm.

[0039] Specifically, the principle of this utility model is as follows: In use, the valve body is first placed on the central positioning base of the base, using the positioning base as a unified reference for initial positioning. Then, the four-way clamping mechanism is operated: the fine-tuning screw of the first radial clamping block pushes the abutment seat, cooperating with the contact plate in the slot of the second radial clamping block and the fine-tuning screws on both sides to precisely clamp the valve body longitudinally; then, the upper clamps of the third and fourth radial clamping blocks are flipped around the hinge, causing the valve body to be inserted into the clamping groove. The clamping bolts passing through the through holes of the upper clamps are tightened and the locking nuts are tightened to securely clamp the valve body laterally. During this process, reinforcing ribs enhance the rigidity of the clamping blocks, the square base ensures overall stability, and the compatible stepped countersunk bolts ensure reliable component connections, ultimately achieving precise positioning of the valve body without offset or deformation, meeting the requirements of high-precision turning machining.

Claims

1. A high-precision valve body turning jig characterized by, The device includes a base with a positioning base at its center. The base has multiple sets of through holes and stepped countersunk holes. A four-way synchronous clamping mechanism is provided on the upper surface of the base. The four-way synchronous clamping mechanism includes opposing first radial clamps, second radial clamps, and opposing third and fourth radial clamps. The first and second radial clamps clamp the valve body by adjusting the fine-tuning screws. The third and fourth radial clamps clamp the valve body by tightening the clamping bolts.

2. The high-precision valve body turning fixture according to claim 1, wherein The base is a square substrate with chamfered edges at the four corners.

3. The high-precision valve body turning fixture according to claim 2, wherein, The inner sides of the first radial clamping block and the second radial clamping block are provided with reinforcing ribs, which are fixedly connected to the upper surface of the base by bolts.

4. The high-precision valve body turning fixture according to claim 3, wherein The first radial clamping block has a threaded hole, and the fine-tuning screw is movably connected to the first radial clamping block through the threaded hole. The fine-tuning screw has an abutment seat at one end near the inner side of the first radial clamping block.

5. The high-precision valve body turning fixture according to claim 4, wherein, The top of the second radial clamping block is provided with a slot; the connecting part of the contact plate is inserted into the slot and locked at its top by a locking bolt, and the contact plate abuts against the valve body through the contact part.

6. The high-precision valve body turning fixture according to claim 5, wherein The second radial clamping block has threaded holes on both sides near the slot, and a set of fine-tuning screws is installed in each threaded hole. The inner end of the fine-tuning screw abuts against the contact plate.

7. The high-precision valve body turning fixture according to claim 6, wherein The third radial clamping block includes a lower clamping block and an upper clamping block. A clamping groove is provided between the lower clamping block and the upper clamping block. The lower clamping block and the upper clamping block are movably hinged on one side and fixedly connected on the other side by clamping bolts.

8. The high-precision valve body turning fixture according to claim 7, wherein, The bottom end of the clamping bolt is hinged to the lower clamp, and the upper clamp has a through hole. The clamping bolt passes through the through hole and is locked in place by a nut.

9. The high-precision valve body turning fixture according to claim 8, wherein, The fourth radial clamping block structure is the same as the third radial clamping block structure, and is arranged opposite to the third radial clamping block. The bottom clamping block is fixedly connected to the base by bolts.

10. The high-precision valve body turning fixture according to claim 9, wherein, The stepped countersunk hole specifications are Φ13-Φ19 to be compatible with M12-M16 bolts.

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