A fixture and method for machining eccentric rotary features of multi-pass complex valves

Abstract

The application discloses a clamp for machining eccentric rotation characteristics of a multi-channel complex valve, which comprises a disc-shaped base, a left block, a right block, an upper block, a lower supporting block and an eccentric positioning device, cross-shaped dovetail grooves are arranged on the disc-shaped base and penetrate through the side wall of the disc-shaped base, the left block and the right block are arranged on the two sides of the disc-shaped base and are connected with the disc-shaped base through the dovetail grooves, the upper block and the lower supporting block are arranged on the upper side and the lower side of the disc-shaped base and are connected with the disc-shaped base through the dovetail grooves, the left block, the right block, the upper block and the lower supporting block slide on the dovetail grooves, and the upper block is provided with a threaded hole for mounting a pressing screw. The clamp is simple and convenient to operate, stable and reliable in function, and can meet the product batch production requirements.

Description

Technical Field

[0001] This invention belongs to the field of machining technology and relates to a fixture and method for machining the eccentric rotation features of complex multi-channel valves. Background Technology

[0002] Valves are critical structures in the valve assembly of spacecraft and are widely used. The manufacturing precision of valve nozzles, seats, and inner bores significantly affects the product's performance. Therefore, the dimensional accuracy, form and position accuracy, and surface roughness requirements for valve body rotary features are extremely high. High-precision rotary features are typically machined by turning. Due to the complex shape of multi-way valves, three-jaw chucks on lathes are unsuitable for clamping them. While four-jaw chucks are used, the adjustment process is cumbersome. When high precision is required, the adjustment work becomes even more difficult, demanding a high level of skill from operators and significantly hindering the yield and production efficiency of multi-way valve manufacturing. With the increasing use of difficult-to-machine materials such as high-temperature alloys and low-temperature stainless steel in valves, ensuring manufacturing precision often requires increasing spindle speeds. The dynamic balance problem during valve eccentric machining becomes particularly prominent, further restricting product yield and processing efficiency.

[0003] Patent CN207642751U discloses a machining fixture for non-rotational center features of a cuboid four-way valve body. The fixture's main structure consists of a circular base, four stops, and a mandrel. The fixture clamps and limits the four sides of the cuboid valve using the stops and mandrel. The axis of the valve's rotational feature is ensured by the positions of the stops on the circular base and the mandrel. When machining other rotational features on the four-way valve, the parts need to be rotated and the stops repositioned. Due to the limitations of the fixture's structure and positioning method, this fixture is only suitable for machining cuboid valve bodies with small external dimensions. Furthermore, when the valve body's external dimensions change, the positioning pin holes or stops on the circular base need to be re-machined. Repeated machining inevitably renders the fixture unusable. When the valve body does not have a through hole, or when the axis of the rotational feature to be machined is not perpendicular to the mandrel axis but intersects it, this fixture cannot be used for machining. Additionally, the fixture lacks a designed balancing block installation position, failing to address the dynamic balance problem during machining.

[0004] Patent CN112453971A discloses a turning fixture for a multi-channel valve body with a relatively complex shape. This fixture mainly consists of a disc, supports, and a mandrel. The supports are evenly distributed on the disc at 90° intervals. In use, the valve body is fitted onto the mandrel, which is fixed to two opposing supports. The other two opposing supports provide auxiliary clamping. After machining a certain rotary feature, the part can be rotated to adjust the angle for machining other rotary features. This fixture uses the valve body's rotation axis as a reference and can machine rotary features whose axis intersects the rotation axis perpendicularly. However, it cannot machine rotary features whose axis is offset from the rotation axis. Furthermore, due to the structure of the disc base and the auxiliary support method of the two supports, when the part's dimensions change, the support positioning holes, mandrel, and supports all need to be re-machined. Therefore, this fixture is only suitable for machining specific valve bodies. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a fixture and method for machining the eccentric rotation features of complex multi-channel valves.

[0006] To achieve the above objectives, the present invention employs the following technical solutions:

[0007] A fixture for machining the eccentric rotation feature of a complex multi-channel valve includes a disc-shaped base, a left stop, a right stop, an upper stop, a lower support block, and an eccentric positioning device. The disc-shaped base has cross-shaped dovetail grooves that penetrate the sidewalls of the disc-shaped base. The left and right stops are located on opposite sides of the disc-shaped base and connected to it via the dovetail grooves. The upper and lower support blocks are located on the upper and lower sides of the disc-shaped base and connected to it via dovetail grooves. The left, right, upper, and lower support blocks slide on the dovetail grooves. The upper stop has threaded holes for installing clamping bolts.

[0008] As a preferred embodiment, the eccentric positioning device includes a movable support block, a trapezoidal screw, and a blocking block. The movable support block has a T-shaped structure with a raised rib, and the raised rib of the movable support block has a threaded hole that mates with the trapezoidal screw. The movable support block is assembled on the lower support block, and the blocking block is located on one side of the trapezoidal screw for limiting the position of the trapezoidal screw.

[0009] The eccentric positioning device has a simple structure. When different valve body products have different rotational characteristics and different eccentricities, the moving support block is moved along the square groove on the lower support block by rotating the trapezoidal screw, thereby adjusting the eccentricity. When machining valve bodies with different shapes, it is only necessary to configure the corresponding pin holes in the rough machining stage of the parts to achieve the positioning of the parts on the moving support block.

[0010] In a further preferred embodiment, the left stop block, right stop block, upper stop block, and lower support block are all positioned and attached to the disc-shaped base by bolts and washers.

[0011] Further preferably, the left and right stops are respectively provided with threaded holes, and surface support or screw support can be selected according to the valve's shape characteristics.

[0012] Further preferably, the left stop block and the right stop block are each provided with a stop wedge block 1, and the upper stop block and the lower support block are each provided with a stop wedge block 2.

[0013] Furthermore, preferably, the contact surfaces of the left stop block, right stop block, upper stop block, lower support block, stop wedge block 1, and stop wedge block 2 are all inclined planes, and the angle of the inclined plane is a self-locking angle. When the fixture and the part rotate at high speed, due to the centrifugal force, the stop block tends to move centrifugally. Due to the inclined surface cooperation with the wedge block, the centrifugal movement is prevented. The higher the rotation speed, the greater the force between the left stop block, right stop block, upper stop block, lower support block, and stop wedge block, and the more secure the clamping.

[0014] Further preferably, one side of the disc-shaped base has an arc-shaped through groove along the circumferential direction, and the arc-shaped through groove is connected to a standard counterweight plate by bolts and washers. The dimensions of the arc-shaped through groove and the standard counterweight plate are related, which allows the standard counterweight plate to be installed at any position on the right side of the disc-shaped base.

[0015] This invention includes a "clamp-valve body dynamic balancing" balancing algorithm. The balancing algorithm is based on the two-plane balance theory. It calculates the counterweight weight and installation position based on factors such as the size of the disc-shaped base, the mass and center of gravity of the clamp parts, and the mass and center of gravity of the valve body. The system consisting of the clamp, valve body, and counterweight is balanced by referring to the balancing algorithm.

[0016] The balancing algorithm is based on the two-plane dynamic balancing theory of rigid rotors, establishing a dynamic balancing calculation model for the "clamp-valve body" system. The dynamic balancing of a rigid rotor can be understood as, on selected equivalent planes T′ and T″, increasing or decreasing mass at specific locations until the sum of the mass-radius product vectors on the equivalent planes is zero, i.e. (n1 and n2 are the quantities of unbalanced masses on the equivalent planes T′ and T″, respectively).

[0017] The balancing algorithm picks up the center-of-gravity coordinates of each component in the "clamp-valve body" system and transfers these coordinates to the dynamic balance calculation model. Since only the position of the counterweight can move in this system, only the counterweight mass and the spatial coordinates of its center of gravity are variables. The balancing algorithm uses the dynamic balance deviation... The objective function is the spatial coordinates of the counterweight's center of mass, which are the parameters of the particle swarm optimization. The particle swarm optimization algorithm is used to optimize the spatial coordinates of the counterweight. When the dynamic balance deviation σ is within the allowable deviation range, the optimization process ends. The obtained spatial coordinates of the counterweight's center of mass can then provide guidance for the installation position of the counterweight.

[0018] The present invention also discloses a method for machining the eccentric rotation feature of a multi-channel complex valve using the above-mentioned fixture.

[0019] The present invention has the following advantages:

[0020] This invention can accommodate the clamping of multi-channel valve body parts with a wide range of dimensions, and can also accommodate the machining of valve bodies that do not have through-rotation features. By configuring corresponding pin holes on the parts, it can also accommodate the machining of valve bodies with eccentric rotation features whose rotation axis is not perpendicular to or intersects with the through-rotation axis of the valve body. Furthermore, the balancing algorithm of this invention can achieve precise placement of counterweights, resulting in a better dynamic balance state and improving the machining efficiency and manufacturing accuracy of valve eccentric rotation features. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the assembly of the present invention with the valve body to be processed;

[0022] Figure 2 This is a schematic diagram of the valve body structure to be processed;

[0023] Figure 3 This is a schematic diagram of a disc-shaped base structure;

[0024] Figure 4 This is a schematic diagram of the left and right stop blocks.

[0025] Figure 5 This is a schematic diagram of the lower support block structure;

[0026] Figure 6 This is a schematic diagram of the upper stop block structure;

[0027] Figure 7 This is a schematic diagram of a standardized counterweight structure;

[0028] Figure 8 This is a schematic diagram of the pin structure;

[0029] Figure 9 Schematic diagram of the movable support block structure

[0030] Figure 10 Schematic diagram of the stop wedge block 1;

[0031] Figure 11 Schematic diagram of the stop wedge block 2;

[0032] Figure 12 This is a schematic diagram of the balancing algorithm.

[0033] In the diagram: 1-Disc-shaped base, 2-Stop wedge block 1, 3-Washer 1, 4-Screw 1, 5-Left and right stops, 6-Lower support block, 7-Screw 2, 8-Moving support block, 9-Trapezoidal screw, 10-Block, 11-Counterweight screw washer, 12-Counterweight screw, 13-Counterweight block, 14-Part to be processed, 15-Pin, 16-Upper stop block screw, 17-Washer 2, 18-Washer 3, 19-Stop wedge block 2, 20-Upper stop block. Detailed Implementation

[0034] The present invention will now be described in detail with reference to the accompanying drawings.

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0036] Example 1:

[0037] A valve body 1 to be processed has a multi-pass structure and has a total of 5 rotary features from 1a to 1e. 1a, 1b, 1c, and 1d are nozzles, and 1e is an internal rotary feature. The rotary axes of nozzle 1d and nozzle 1a are parallel, and the internal rotary feature 1e and nozzle 1b are coaxial.

[0038] A fixture for machining the eccentric rotation feature of a multi-way valve includes a disc-shaped base 1. The main body of the disc is a disc with a cylindrical short shaft on the back. The disc has perpendicular dovetail grooves, four waist-shaped through grooves, and four screw holes. A left stop block, a lower support block, a right stop block, and an upper stop block are respectively assembled on the dovetail grooves and can slide along the dovetail grooves. They are connected to the disc-shaped base at certain positions through washers, screws, and stop wedge blocks.

[0039] The eccentric positioning device includes a movable support block, a trapezoidal screw, and a plug. The movable support block has a T-shaped structure with a raised rib. The raised rib of the movable support block has a threaded hole that mates with the trapezoidal screw. The movable support block is assembled on the lower support block. The position of the movable support block can be adjusted by rotating the trapezoidal screw.

[0040] The valve body to be processed is mounted on the eccentric support positioning device by cylindrical pins and diamond pins. At this time, the rotation features 1a, 1b, 1d and 1e of the valve body to be processed form a certain angle with the rotation axis of the disc-shaped base. When processing the valve body nozzle 1a, the end face of the rotation feature 1e of the valve body to be processed is made to fit with the left stop by moving the left stop. At this time, the rotation axis of the nozzle 1a automatically coincides with the rotation axis of the disc-shaped base. Tighten the left stop screw to fix the position of the left stop. At this time, the rotation axis of the valve body nozzle 1a to be processed cannot be moved. Move the right stop in sequence and tighten the screw for auxiliary positioning and clamping. The valve body to be processed is then reliably assembled on the fixture. At this time, the rotation axis of the valve body nozzle 1a to be processed coincides with the rotation axis of the machine tool spindle.

[0041] Using 3D design software such as ProE, the current clamping state of the fixture and valve body described in this invention is virtually assembled. The dimensions of the disc-shaped base, the mass and center of gravity of the fixture parts, and the mass and center of gravity of the valve body are picked up. The weight information and center of gravity coordinates are input into the algorithm script for calculation. After the counterweight is installed according to the counterweight weight and installation position given by the dynamic balance algorithm, the valve body nozzle 1a can be turned.

[0042] After the valve body nozzle 1a is machined, proceed with the machining of valve body nozzle 1d. Before machining nozzle 1d, loosen the left stop block screw, right stop block screw, and upper stop block clamping screw, remove the left and right stops, rotate the valve body 180° so that nozzle 1d faces forward, move the right stop block so that the valve body end face fits against it, rotate the trapezoidal screw, adjust the position of the moving support block so that the rotation axis of nozzle 1d coincides with the rotation axis of the disc-shaped base, tighten the right stop block screw to fix the right stop block, then move the left stop block to any position, tighten the left stop block screw to fix the position of the left stop block, tighten the screw to press against the left side nozzle end face of the valve body to achieve auxiliary clamping, finally tighten the clamping screw at the upper stop block to clamp the valve body, and finally use the dynamic balance balancing algorithm to calculate the weight and installation position of the counterweight.

[0043] The fixture and machining method provided in this embodiment for machining the eccentric rotation feature of valves solve the problems of valve body clamping and dynamic balancing. It is simple and convenient to operate, and has stable and reliable functions, which can meet the needs of mass production of products.

[0044] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A fixture for machining the eccentric rotational features of complex multi-channel valves, characterized in that: The device includes a disc-shaped base, a left stop block, a right stop block, an upper stop block, a lower support block, an eccentric positioning device, and a standard counterweight plate. The disc-shaped base has cross-shaped dovetail grooves that penetrate the sidewalls of the disc-shaped base. The left and right stop blocks are located on opposite sides of the disc-shaped base and are connected to it via the dovetail grooves. The upper stop block and lower support block are located on the upper and lower sides of the disc-shaped base and are connected to it via the dovetail grooves. The left, right, upper, and lower support blocks slide on the dovetail grooves. The upper stop block has threaded holes for installing clamping screws. The eccentric positioning device includes a movable support block, a trapezoidal screw, and a plug. The movable support block is a T-shaped structure with a rib. The rib of the movable support block has a threaded hole that mates with the trapezoidal screw. The lower support block has a square groove. The movable support block is assembled in the square groove of the lower support block and can move along the square groove under the action of the trapezoidal screw. The plug is located on one side of the trapezoidal screw and is used to limit the movement of the trapezoidal screw. The left stop block, right stop block, upper stop block, and lower support block are all positioned and attached to the disc-shaped base by bolts, washers, and stop wedge blocks; The left and right blocks are each provided with a stop wedge block 1, and the upper block and lower support block are each provided with a stop wedge block 2; the contact surfaces of the left block, right block, upper block, lower support block, stop wedge block 1 and stop wedge block 2 are all inclined surfaces, and the included angle of the inclined surfaces is a self-locking angle; The disc-shaped base has an arc-shaped through groove on one side along the circumferential direction, and the arc-shaped through groove is connected to the standard counterweight plate by bolts and washers.

2. The fixture for machining the eccentric rotation feature of a complex multi-channel valve according to claim 1, characterized in that: The left and right stops are respectively provided with threaded holes, and surface support or screw support can be selected according to the valve's shape characteristics.

3. A fixture for machining the eccentric rotation feature of a complex multi-channel valve according to claim 1, characterized in that: The standard counterweight plate can be installed at any predetermined position along the circumference on the right side of the disc-shaped base via an arc-shaped through slot.

4. A method for machining the eccentric rotary feature of a multi-channel complex valve using the fixture described in claim 1, characterized in that, Includes the following steps: The valve body to be processed is mounted on the eccentric positioning device using cylindrical pins and diamond pins. Move the left or right stop block to make the end face of the valve body to be processed fit with the corresponding stop block, and make the rotation axis of the eccentric rotation feature of the valve body to be processed coincide with the rotation axis of the disc-shaped base; move the other side stop block for auxiliary positioning and clamping, and clamp the valve body to be processed by the clamping screw at the upper stop block; Based on the dimensions of the disc-shaped base, the mass and center of gravity of the fixture parts, and the mass and center of gravity of the valve body, the counterweight weight and installation position of the standard counterweight plate are calculated using the fixture-valve body dynamic balance balancing algorithm. After the standard counterweight plate is installed at the corresponding position of the arc-shaped through groove, the turning of the eccentric rotation feature to be processed is carried out. When machining another eccentric rotary feature, loosen the stop block and clamping screw, adjust the valve body direction, rotate the trapezoidal screw to adjust the position of the moving support block, so that the rotation axis of the other eccentric rotary feature coincides with the rotation axis of the disc-shaped base, re-fix the valve body to be machined, and install the standard counterweight plate according to the fixture-valve body dynamic balance balancing algorithm before turning.

5. The method according to claim 4, characterized in that: The clamp-valve body dynamic balancing algorithm is based on the two-dimensional dynamic balancing theory of rigid rotors. It establishes a dynamic balancing calculation model of the clamp-valve body system, picks up the centroid coordinates of each component in the clamp-valve body system, transfers the centroid coordinates to the dynamic balancing calculation model, and uses the mass and centroid spatial coordinates of the standard counterweight plate as variables, with the dynamic balance deviation as the objective function. The particle swarm algorithm is used to optimize the spatial coordinates of the standard counterweight plate. When the dynamic balance deviation is within the allowable deviation range, the installation position of the standard counterweight plate is obtained.

6. The method according to claim 4, characterized in that: When machining valve body nozzle 1a, the left stop is moved to make the end face of the valve body rotation feature 1e fit with the left stop, so that the rotation axis of nozzle 1a coincides with the rotation axis of the disc-shaped base; when machining valve body nozzle 1d, the valve body is rotated 180°, the right stop is moved to make the end face of the valve body fit with the right stop, and the position of the moving support block is adjusted by rotating the trapezoidal screw, so that the rotation axis of nozzle 1d coincides with the rotation axis of the disc-shaped base.

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