A high-precision valve body horizontal milling fixture

Abstract

This utility model provides a high-precision valve body horizontal milling fixture, belonging to the field of machining technology. The high-precision valve body horizontal milling fixture includes a replaceable positioning fixture, which comprises a positioning base and a replaceable tapered clamping plate. The replaceable tapered clamping plate is fixedly installed to the positioning base by bolts. An inner tapered jaw is provided at the center of the replaceable tapered clamping plate, and a U-shaped clamping block is provided above it. An anti-vibration mechanism is provided at the front end of the replaceable tapered clamping plate, and the anti-vibration mechanism abuts against the valve body through a clamping screw. Multiple sets of stepped countersunk holes are formed on the surface of the replaceable tapered clamping plate for fixed installation with the positioning base. The inner tapered angle of the inner tapered jaw is 30°. This utility model can solve the problems of inconsistent positioning benchmarks, single clamping dimensions, poor adaptability, and low adjustment accuracy in current horizontal milling fixtures, which lead to a high cumulative error rate in valve body horizontal milling and make it difficult to meet the flange uniform groove angle tolerance requirements.

Description

Technical Field

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

[0002] In petrochemical pipeline systems, the valve body of a DN80 diameter 150 / 300 lb top-mount valve needs to be machined by horizontal milling to produce evenly distributed grooves on the flange, and the angular tolerance needs to be strictly controlled within ±0.5°. However, traditional horizontal milling fixtures cannot meet this precision requirement, and the cumulative error deviation rate is as high as 42%. Currently, traditional horizontal milling fixtures mostly adopt a fixed, integrated structure. The positioning datum needs frequent adjustment as the valve body specifications change, and the lack of a unified datum carrier makes it easy for deviations to occur when switching datums. The clamping mechanism of the fixture is mostly single-sided or bi-directional clamping, which cannot fix the valve body from multiple dimensions. The vibration of horizontal milling can easily cause the valve body to shift, which in turn leads to the displacement of the flange groove angle. At the same time, traditional fixtures have poor adaptability. For different specifications of valve bodies, the entire fixture set must be replaced, which not only increases equipment costs, but also further amplifies the cumulative error due to the datum reset during the fixture replacement process. In addition, the clamping components of the fixture lack a fine adjustment structure, resulting in low clamping force control accuracy. Too tight a clamp can easily cause valve body deformation, while too loose a clamp can not suppress vibration, both of which will affect the machining accuracy of the flange groove. In summary, existing horizontal milling fixtures suffer from inconsistent positioning datums, a single clamping dimension, poor adaptability, and low adjustment accuracy, resulting in a high rate of cumulative error exceeding tolerances in valve body horizontal milling and making it difficult to meet the flange uniformly distributed groove angle tolerance requirements. Utility Model Content

[0003] In view of this, the present invention provides a high-precision valve body horizontal milling fixture, which can solve the problems of inconsistent positioning reference, single clamping dimension, poor adaptability and low adjustment accuracy of the current horizontal milling fixtures, resulting in a high rate of cumulative error exceeding the tolerance in valve body horizontal milling and making it difficult to meet the flange uniform groove angle tolerance requirements.

[0004] This utility model is implemented as follows: This utility model provides a high-precision valve body horizontal milling fixture, which includes a replaceable positioning fixture. The replaceable positioning fixture includes a positioning base and a replaceable tapered clamping plate. The replaceable tapered clamping plate is fixedly installed to the positioning base by bolts. The replaceable tapered clamping plate has an inner tapered jaw at its center and a U-shaped clamping block above it. The front end of the replaceable tapered clamping plate is provided with an anti-vibration mechanism, which abuts against the valve body through a clamping screw.

[0005] The technical advantages of the high-precision valve body milling fixture provided by this utility model are as follows: The replaceable positioning fixture achieves a unified positioning reference by installing a replaceable tapered clamping plate on the positioning base; the bolt fixing method ensures a stable connection between the clamping plate and the base, avoiding reference offset; the inner tapered jaw can accurately fit with the corresponding tapered surface of the valve body to form a centering positioning, ensuring the angular reference accuracy of the flange uniformly distributed groove machining; the U-shaped clamping block assists in clamping from above, and cooperates with the clamping screw of the anti-vibration mechanism to abut laterally, forming a three-dimensional fixation that combines centering from above and below and laterally, avoiding valve body vibration or displacement during milling, and reducing the risk of angular tolerance exceeding tolerance.

[0006] Based on the above technical solution, the high-precision valve body horizontal milling fixture of this utility model can be further improved as follows: The replaceable tapered plate has multiple sets of stepped countersunk holes on its surface for fixed installation with the positioning base.

[0007] The beneficial effects of adopting the above-mentioned improved scheme are as follows: multiple sets of stepped countersunk holes provide flexible installation positions for the bolt connection between the clamping plate and the base. The corresponding countersunk hole can be selected according to the weight of the valve body or the stress requirements, ensuring that the connection point is subjected to balanced force, avoiding local stress concentration that could cause the clamping plate to deform, and ensuring the stability of the positioning reference. The stepped countersunk holes are compatible with bolts of different specifications, improving the flexibility of fixture assembly. At the same time, the countersunk hole structure allows the bolt head to be embedded in the clamping plate, preventing the bolt from protruding and interfering with valve body clamping or horizontal milling.

[0008] Furthermore, the inner cone angle of the inner cone jaw is 30°.

[0009] The beneficial effects of adopting the above-mentioned improved scheme are as follows: by setting the inner cone angle of 30°, the corresponding cone surface of the DN80 diameter 150 / 300 lb valve body has high compatibility and can achieve large-area fitting. Compared with 45°, the centering accuracy of the 30° cone surface is higher, which can accurately limit the radial displacement of the valve body and provide a stable radial reference for the flange uniform groove angle tolerance of ±0.5°. At the same time, the inclination angle of the 30° cone surface is moderate, which not only facilitates the quick clamping of the valve body and avoids clamping difficulties caused by the angle being too small, but also enhances the positioning stability through the self-locking effect of the cone surface and reduces the valve body offset caused by the milling cutting force.

[0010] Furthermore, the U-shaped clamping block includes fixed uprights on both sides and a transverse clamping block at the top.

[0011] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by setting a U-shaped structure to form an encircling clamp from both sides and the top of the valve body, compared with the traditional single-sided clamping, the clamping force can be distributed more evenly, avoiding the valve body from tilting or deforming due to force on one side, ensuring the flatness of the flange machining surface, and indirectly improving the angular tolerance accuracy; by fixing the uprights on both sides to provide stable support for the transverse clamping block, it is ensured that the transverse clamping block can be accurately aligned with the top of the valve body, avoiding the positioning deviation caused by the transverse clamping block offset during clamping.

[0012] Furthermore, a nut is provided at the bottom of the fixed pole, which is fixedly connected to the replaceable tapered clamp plate by bolts, and a screw is provided at the top, which is locked and fixed to the transverse clamp by nuts.

[0013] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by adjusting the height of the transverse clamping block by rotating the nut, it can be adapted to valve bodies of different heights, thus improving the versatility of the clamp; by fixing the upright and the clamping plate to ensure a stable connection, it can prevent the U-shaped clamping block from shifting due to the loosening of the upright, thus ensuring the consistency between the clamping reference and the positioning reference.

[0014] Furthermore, through holes are provided on both sides of the transverse clamping block for fitting the screw at the top of the fixed pole.

[0015] Furthermore, the vibration damping mechanism includes locking blocks on both sides, with a locking block at the bottom of the locking block and oblique reinforcing ribs on the outer side.

[0016] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the auxiliary clamping is formed from both sides of the valve body by the two-sided locking clamps, and the centering of the inner cone jaw and the upper and lower clamping of the U-shaped clamping block are combined to form an all-round anti-vibration fixation, which effectively absorbs the cutting vibration during horizontal milling, avoids the flange groove angle deviation caused by vibration, and reduces the angle tolerance deviation rate.

[0017] Furthermore, the front end of the replaceable tapered clamping plate is provided with a groove for adapting the clamping block, and a positioning countersunk hole for fixing the locking clamping block is provided on one side of the corresponding groove position.

[0018] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: through the precise matching of the slot and the block, the fastening clamp can be quickly positioned and installed, ensuring the coaxiality of the fastening clamps on both sides and the inner cone jaw, avoiding the imbalance of lateral clamping force caused by the position deviation of the fastening clamp, and ensuring the lateral positioning accuracy of the valve body. The countersunk hole provides an installation reference for the bolts that fix the locking block, allowing the bolts to pass precisely through the countersunk hole to fix the locking block, avoiding the tilting of the locking block caused by bolt installation misalignment. At the same time, the countersunk hole structure allows the bolt head to be embedded in the clamping plate, without interfering with valve body clamping and machining.

[0019] Furthermore, a screw hole is provided on the top of the locking clamp, and a positioning screw hole is provided on the bottom side corresponding to the positioning countersunk hole, for use with fixing bolts to fix and install the locking clamp; the positioning screw hole is located below the oblique reinforcing rib.

[0020] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the upper screw hole provides an adjustment reference for the clamping screw, ensuring that the clamping screw can accurately abut against the valve body laterally; the bottom positioning screw hole corresponds to the positioning countersunk hole of the clamping plate, and the bolts realize a stable connection between the locking clamp and the clamping plate, avoiding the locking clamp from loosening due to processing vibration, and ensuring stable lateral clamping force. The positioning screw hole is located below the inclined reinforcing rib. The reinforcing rib provides structural support for the positioning screw hole, preventing the bottom of the locking block from deforming due to force when the bolt is tightened, ensuring the coaxiality of the screw hole and the countersunk hole, and reducing the positioning deviation caused by the connection gap.

[0021] Furthermore, the clamping screw is connected to the screw hole above the locking block, and the valve body is clamped and fixed by lateral contact.

[0022] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by tightening the screw and the threaded engagement of the screw hole, high-precision adjustment can be achieved. The operator can precisely control the lateral contact force by rotating the screw, which ensures that the valve body is firmly clamped and avoids excessive contact that could cause deformation of the valve body, thus ensuring the angular accuracy of the flange groove machining. By using a lateral abutment method to supplement the clamping from the valve body laterally, and in conjunction with the inner cone bayonet and U-shaped clamping block, the cutting vibration during horizontal milling is effectively suppressed, reducing the angular deviation caused by vibration, and further reducing the cumulative error deviation rate.

[0023] Compared with existing technologies, the advantages of this high-precision valve body milling fixture are as follows: the interchangeable positioning fixture uses a positioning base as a unified positioning reference, coupled with a replaceable tapered clamping plate, ensuring reference stability and adaptability to valve bodies of different specifications; the valve body is centered and positioned by designing a 30° inner tapered jaw, providing a precise radial reference for the flange uniform groove angle tolerance of ±0.5°; the U-shaped clamping block clamps from the top and bottom, and the anti-vibration mechanism is laterally fixed by a locking clamping block and a clamping screw, forming a three-dimensional anti-vibration fixation, which significantly reduces the angle deviation caused by milling vibration. Furthermore, the design incorporates multiple sets of stepped countersunk holes and adjustable screws, improving the fixture's assembly flexibility and adjustment accuracy, reducing the cumulative error rate, enhancing versatility, reducing equipment costs, and meeting the high-precision milling requirements of DN80 diameter 150 / 300 lb valve bodies. Attached Figure Description

[0024] 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.

[0025] Figure 1 This is a schematic diagram of a high-precision valve body horizontal milling fixture. Figure 2 Top view of the replaceable tapered clamping plate; Figure 3 A schematic diagram of the anti-vibration mechanism's locking clamp structure; Figure 4Schematic diagram of the bottom structure of the fixation clamping block; The attached diagram lists the components represented by each number as follows: 10. Replaceable positioning fixture; 11. Positioning base; 12. Replaceable tapered clamping plate; 13. Inner tapered jaw; 14. U-shaped clamping block; 15. Vibration damping mechanism; 16. Clamping screw; 17. Stepped countersunk hole; 18. Fixed upright; 19. Horizontal clamping block; 20. Locking clamping block; 21. Clamping block; 22. Diagonal reinforcing rib; 23. Slot; 24. Positioning countersunk hole; 25. Positioning screw hole. Detailed Implementation

[0026] 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.

[0027] like Figure 1-4 The image shows an embodiment of a high-precision valve body milling fixture provided by this utility model. In this embodiment, it includes a replaceable positioning fixture 10, which includes a positioning base 11 and a replaceable tapered clamping plate 12. The replaceable tapered clamping plate is fixedly installed to the positioning base by bolts. The replaceable tapered clamping plate has an inner tapered jaw 13 at its center and a U-shaped clamping block 14 above it. The front end of the replaceable tapered clamping plate is provided with an anti-vibration mechanism 15, which abuts against the valve body through a clamping screw 16. In the above technical solution, the replaceable tapered plate has multiple sets of stepped countersunk holes 17 on its surface for fixed installation with the positioning base.

[0028] Furthermore, in the above technical solution, the inner cone angle of the inner cone bayonet is 30°.

[0029] Furthermore, in the above technical solution, the U-shaped clamping block includes fixed uprights 18 on both sides and a transverse clamping block 19 at the top.

[0030] Furthermore, in the above technical solution, a nut is provided at the bottom of the fixed pole, which is fixedly connected to the replaceable tapered clamp plate by bolts, and a screw is provided at the top, which is locked and fixed to the transverse clamp by a nut.

[0031] Furthermore, in the above technical solution, through holes are provided on both sides of the transverse clamping block for fitting the screw at the top of the fixed pole.

[0032] Furthermore, in the above technical solution, the vibration damping mechanism includes two fixing blocks 20 on both sides, a locking block 21 is provided at the bottom of the fixing block, and an oblique reinforcing rib 22 is provided on the outer side.

[0033] Furthermore, in the above technical solution, the front end of the replaceable tapered plate is provided with a slot 23 for adapting the card block, and a positioning countersunk hole 24 for fixing the locking clamp is provided on one side of the slot.

[0034] Furthermore, in the above technical solution, a screw hole is provided above the locking clamp, and a positioning screw hole 25 is provided on the bottom side corresponding to the positioning countersunk hole position, for use with fixing bolts to fix and install the locking clamp; the positioning screw hole is located below the oblique reinforcing rib.

[0035] Furthermore, in the above technical solution, the clamping screw is connected to the screw hole above the locking block, and the valve body is clamped and fixed by lateral contact.

[0036] The following is a specific embodiment: The positioning base is made of 45 steel base plate with a hardness of HRC28-32 and a diameter of 400×320×30mm. There are 4 sets of Φ15-Φ21 stepped countersunk holes on the base plate, which are adapted to M14-M18 bolts for fixing with replaceable tapered plates. Two models of replaceable tapered clamping plates are available: Model A is suitable for 150-pound valve bodies, with a main body size of 280×180×25mm. The inner tapered jaw is designed with a 30° inner tapered surface, and the bottom of the inner tapered surface has a 2mm deep annular stop. The inner diameter of the annular stop is precisely matched with the outer diameter of the Φ139.7mm valve body mating end (gap ≤0.02mm); Model B is suitable for 300-pound valve bodies, with the same main body size as Model A. The inner tapered jaw is also a 30° inner tapered surface, and the inner diameter of the annular stop is matched with the outer diameter of the Φ171.4mm valve body mating end. The depth of the annular stop is maintained at 2mm, ensuring that the valve body centering reference is consistent after the two clamping plates are assembled with the positioning base.

[0037] The two fixed uprights are made of Φ20mm 40Cr round steel, with M16 nuts welded to the bottom. They are fixed to the replaceable tapered clamp plate with M16×50 bolts and pre-drilled threaded holes. The top of the uprights is machined with M14 external threads and fitted with M14 lock nuts. The transverse clamping blocks are made of 200×40×15mm Q235 steel plates, with Φ14.5mm through holes on both sides (to accommodate the threads on the top of the uprights). The inner walls of the through holes are polished (Ra≤1.6μm) to ensure smooth lifting and lowering of the transverse clamping blocks.

[0038] The locking clamp is made of No. 45 steel, with a 15×10mm rectangular clamping block machined at the bottom and oblique reinforcing ribs cut on the outside. The replaceable tapered clamping plate has a 15.1×10.1mm rectangular groove at the front end, with a Φ13mm countersunk hole on one side of the groove. An M16 screw hole is made on the top of the locking clamp, and an M12 positioning screw hole is made on one side of the bottom corresponding to the countersunk hole. The clamping screw is an M16×80mm fine-pitch screw (2mm pitch).

[0039] Specifically, the principle of this utility model is as follows: In use, first select a suitable replaceable tapered clamping plate according to the valve body specifications, and fix it to the positioning base using stepped countersunk holes and bolts to ensure uniform reference. Place the valve body into the 30° inner tapered jaw of the clamping plate for centering, then adjust the U-shaped clamping block: fix the upright rod with bolts at the bottom end, and rotate the top screw to adjust the height of the transverse clamping block, so that the transverse clamping block presses against the top of the valve body. Next, install the vibration damping mechanism, inserting the bottom clamping block of the locking clamping block into the clamping plate slot, and fixing it with bolts passing through the positioning countersunk holes and the positioning screw holes of the locking clamping block. Finally, rotate the clamping screw above the locking clamping block to make it laterally abut against the valve body. The three-dimensional fixing structure suppresses horizontal milling vibration, ensures the machining angle accuracy of the flange grooves, and meets process requirements.

Claims

1. A high precision valve body horizontal milling fixture, characterized in that, It includes a replaceable positioning fixture, which includes a positioning base and a replaceable tapered clamping plate. The replaceable tapered clamping plate is fixedly installed to the positioning base by bolts. The replaceable tapered clamping plate has an inner tapered jaw at the center and a U-shaped clamping block above it. The front end of the replaceable tapered clamping plate is equipped with an anti-vibration mechanism, which abuts against the valve body through a clamping screw.

2. A high precision valve body horizontal milling fixture according to claim 1, characterized in that, The replaceable tapered plate has multiple sets of stepped countersunk holes on its surface for fixed installation with the positioning base.

3. A high precision valve body horizontal milling fixture according to claim 2, wherein The inner cone angle of the inner cone jaw is 30°.

4. The high precision valve body horizontal milling fixture of claim 3, wherein, The U-shaped clamping block includes fixed uprights on both sides and a horizontal clamping block at the top.

5. A high precision valve body horizontal milling fixture according to claim 4, wherein The bottom of the fixed pole is equipped with a nut, which is fixedly connected to the replaceable tapered clamp plate by bolts. The top is equipped with a screw rod, which is locked and fixed to the horizontal clamping block by a nut.

6. A high precision valve body horizontal milling fixture according to claim 5, wherein The horizontal clamping block has through holes on both sides for fitting the screw at the top of the fixed pole.

7. A high precision valve body horizontal milling fixture according to claim 6, wherein The vibration damping mechanism includes locking blocks on both sides, with a locking block at the bottom of the locking blocks and oblique reinforcing ribs on the outer side.

8. A high precision valve body horizontal milling fixture according to claim 7, wherein The front end of the replaceable tapered clamping plate is provided with a groove for the clamping block, and a positioning countersunk hole for fixing the clamping block is provided on one side of the corresponding groove.

9. A high precision valve body horizontal milling fixture according to claim 8, wherein The locking clamp has a screw hole on the top and a positioning screw hole on the bottom side corresponding to the positioning countersunk hole, which is used to fix the locking clamp with the fixing bolt; the positioning screw hole is located below the oblique reinforcing rib.

10. A high precision valve body horizontal milling fixture according to claim 9, wherein The clamping screw connects to the screw hole above the locking block, and is clamped and fixed by lateral contact with the valve body.

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