Zero-point positioning system, square-hole machining device and method based on the system

Abstract

The present invention relates to a zero-point positioning system, a square hole machining device and a method based on the system. The zero-point positioning system includes a pull stud, which is a complete rotary body structure composed of two semi-rotary body structures. A wire threading hole for the electrode wire a to pass through is provided at the center of the zero-point positioning system. Two positioning wheels a with the same shape and size are arranged symmetrically along the central axis inside the pull stud. The central connection line of the two positioning wheels a is perpendicular to the central axis of the pull stud, so that the position of the electrode wire a is fixed, and different diameter electrode wires a can be replaced by replacing the positioning wheels a with different diameters; the machining device includes the electrode wire a and the electrode wire b, the zero-point positioning system, two positioning wheels b with the same shape and size, an electro-hydraulic servo valve sleeve fixture and a wire electrical discharge machining machine tool; the machining method includes: valve sleeve clamping → square hole machining → valve sleeve rotation → square hole machining. The zero-point positioning system of the present invention can be quickly replaced and has a short wire replacement time, and the device of the present invention has high machining accuracy.

Description

Technical Field

[0001] The present invention belongs to the technical field of high-precision carrier and tactical weapon servo systems, and relates to a zero-point positioning system, a square hole machining device and method based on the system. Background Art

[0002] The aerospace electro-hydraulic servo valve consists of a spool working edge and a valve sleeve / housing working square hole to jointly form a throttle window, realizing the conversion of the servo system's electrical signal to hydraulic actuation, which is a key characteristic of the precision power amplification link. Since the servo throttle window works at a micron-level resolution, the machining requirements for the square hole are micron-level resolution and strict shape and position accuracy requirements.

[0003] For traditional wire electrical discharge machining technology, when facing the machining of hole structures, the perforation operation is cumbersome and time-consuming, the machining efficiency is low, and when machining different holes, the workpiece needs to be frequently clamped, and the clamping error caused by changing the clamping position seriously affects the accuracy of wire electrical discharge machining.

[0004] Therefore, there is an urgent need to research a zero-point positioning system, a square hole machining device and method based on the system to overcome the problem of low machining accuracy. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems existing in the prior art and provide a zero-point positioning system, a square hole machining device and method based on the system.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A zero-point positioning system A includes a pull stud. The pull stud is a complete rotary body structure composed of two semi-rotary body structures. There is a wire threading hole in the center of the zero-point positioning system A for the electrode wire a to pass through. A partial length section of the wire threading hole is located inside the pull stud, denoted as the L section; there are two positioning wheels a with the same shape and size and two positioning wheel pins with the same shape and size inside the pull stud;

[0008] The central axis of the L section coincides with the central axis of the pull stud;

[0009] The two positioning wheel pins are symmetrically distributed on both sides of the central axis of the pull stud. The central axis of the positioning wheel pin is perpendicular to the central axis of the pull stud. One end of the two positioning wheel pins is fixedly connected to the same semi-rotary body structure, and the other end penetrates into the positioning hole on the other semi-rotary body structure;

[0010] The two positioning wheels a are respectively sleeved on the two positioning wheel pins and are symmetrically distributed on both sides of the central axis of the pull stud. The positioning wheel a is coaxially matched with the positioning wheel pin. The distance between the two positioning wheels a is equal to the diameter of the electrode wire a (the distance between the two positioning wheels a = the length of the gap obtained by subtracting the respective radii from the distance between the centers of the two positioning wheels a, and its value is equal to the diameter of the electrode wire a);

[0011] The pull stud is provided with a space for placing two positioning wheels a, and the size of this space is such that the two positioning wheels a can only rotate around their own central axes.

[0012] As a preferred technical solution:

[0013] For a zero-point positioning system A as described above, the diameter of the L section is 1.5 times the diameter of the electrode wire a.

[0014] For a zero-point positioning system A as described above, the two semi-rotary body structures are connected and fixed by fastening bolts.

[0015] For a zero-point positioning system A as described above, the zero-point positioning system A further includes a zero-point positioning center chip protection device, a zero-point locator, and a base. The remaining length section of the wire threading hole is located inside the zero-point positioning center chip protection device, the zero-point locator, and the base. The base is provided with an unlocking air circuit interface and a central blowing air circuit interface for connecting the external air circuit to the zero-point locator;

[0016] The zero-point positioning center chip protection device is used to prevent cutting fluid, chips, and other impurities from entering the internal structure of the zero-point locator, and to avoid the influence of impurities, etc. on the repeat positioning accuracy of the zero-point positioning system A;

[0017] The zero-point locator uses the power source provided by the internal spring thereof, and uses the mechanical structure automatic centering and locking method to fix the position of the pull stud and ensure its repeat positioning accuracy during the replacement process, thereby ensuring the position accuracy of the electrode wire a. During replacement, the unlocking air circuit interface is connected to an air circuit with a certain air pressure. Under the action of the air pressure, the zero-point locator is unlocked from the pull stud. At this time, the pull stud can move freely and realize the function of guiding the replacement of the electrode wire a; the unlocking air circuit interface is used to provide the air pressure source for unlocking the zero-point locator and the pull stud. When ventilated, the air pressure pushes the zero-point locator to unlock, and the pull stud can move freely; when closed, the zero-point locator fixes and clamps the pull stud; the central blowing air circuit interface is used to provide the air pressure source for central blowing, and is ventilated when the zero-point locator is unlocked from the pull stud. Since the sealing between the zero-point positioning center chip protection device and the inner hole wall of the zero-point locator is released during unlocking, it is necessary to introduce an air flow into the air circuit and blow it out from the gap between the zero-point locator and the zero-point positioning center chip protection device to prevent cutting fluid, chips, and other impurities from entering the inside of the zero-point positioning system A along the gap between the zero-point locator and the zero-point positioning center chip protection device.

[0018] The present invention also provides another zero-point positioning system B, including a pull stud. The pull stud is a complete rotary body structure composed of two semi-rotary body structures. A wire threading hole for the electrode wire a to pass through is provided at the center of the zero-point positioning system B. A partial length section of the wire threading hole is located inside the pull stud, denoted as the L section; two positioning wheels a with the same shape and size, two positioning wheel pins with the same shape and size, two guide wheels a with the same shape and size, and two guide wheel pins with the same shape and size are provided inside the pull stud;

[0019] The central axis of the L section coincides with the central axis of the pull stud;

[0020] The two positioning wheel pins are symmetrically distributed on both sides of the central axis of the pull stud. The central axis of the positioning wheel pin is perpendicular to the central axis of the pull stud. One end of the two positioning wheel pins is fixedly connected to the same semi-rotary body structure, and the other end penetrates into the positioning hole on the other semi-rotary body structure;

[0021] The two positioning wheels a are respectively sleeved on the two positioning wheel pins and are symmetrically distributed on both sides of the central axis of the pull stud. The positioning wheel a is coaxially fitted with the positioning wheel pin. The distance between the two positioning wheels a is equal to the diameter of the electrode wire a (the distance between the two positioning wheels a = the gap length obtained by subtracting their respective radii from the distance between the centers of the two positioning wheels a, and its value is equal to the diameter of the electrode wire a);

[0022] A space for placing the two positioning wheels a is provided inside the pull stud. The size of this space enables the two positioning wheels a to only rotate around their own central axes;

[0023] The two guide wheel pins are symmetrically distributed on both sides of the central axis of the pull stud. The central axis of the guide wheel pin is perpendicular to the central axis of the pull stud. One end of the two guide wheel pins is fixedly connected to the same semi-rotary body structure, and the other end penetrates into the positioning hole on the other semi-rotary body structure;

[0024] The two guide wheels a are respectively sleeved on the two guide wheel pins and are symmetrically distributed on both sides of the central axis of the pull stud. The guide wheel a is coaxially fitted with the guide wheel pin. The distance between the two guide wheels a is equal to the diameter of the electrode wire a (the distance between the two guide wheels a = the gap length obtained by subtracting their respective radii from the distance between the centers of the two guide wheels a, and its value is equal to the diameter of the electrode wire a);

[0025] A space for placing the two guide wheels a is provided inside the pull stud. The size of this space enables the two guide wheels a to only rotate around their own central axes;

[0026] The two guide wheels a and the two positioning wheels a are arranged at intervals, and the two guide wheels a are closer to the entrance of the L section than the two positioning wheels a;

[0027] The guide wheel a mainly prevents problems that are likely to occur in the wire threading hole, such as bending, touching the wall, and clogging of the electrode wire a. After adding the guide wheel a, it is equivalent to shortening the distance of the wire threading hole by half, greatly reducing the possibility of the above problems, and indirectly improving the piercing efficiency.

[0028] As a preferred technical solution:

[0029] For a zero-point positioning system B as described above, one end of the two positioning wheel pins and the two guide wheel pins is fixedly connected to the same semi-rotary body structure.

[0030] For a zero-point positioning system B as described above, the distance between the guide wheel a and the positioning wheel a is 1 / 3 of the length of section L; the distance between the guide wheel a and the entrance of section L is 1 / 3 of the length of section L. The purpose of setting the distance in this way is to make the electrode wire evenly distributed in each section of the wire threading hole of the pull stud, reduce the winding and bending that may occur during the electrode wire piercing process, and provide stable support for the electrode wire.

[0031] For a zero-point positioning system B as described above, the diameter of section L is 1.5 times the diameter of the electrode wire a.

[0032] For a zero-point positioning system B as described above, the two semi-rotary body structures are connected and fixed by fastening bolts.

[0033] For a zero-point positioning system B as described above, the zero-point positioning system B further includes a zero-point positioning center chip protection device, a zero-point locator, and a base. The remaining length section of the wire threading hole is located inside the zero-point positioning center chip protection device, the zero-point locator, and the base. The base is provided with an unlocking air circuit interface and a central blowing air circuit interface for connecting the external air circuit to the zero-point locator;

[0034] The zero-point positioning center chip protection device is used to prevent cutting fluid, chips, and other impurities from entering the internal structure of the zero-point locator, and avoid the influence of impurities and the like on the repeat positioning accuracy of the zero-point positioning system B;

[0035] The zero-point locator uses the power source provided by its internal spring and the automatic centering and locking method of the mechanical structure to fix the position of the pull stud and ensure the repeat positioning accuracy during its replacement process, thereby ensuring the position accuracy of the electrode wire a. During replacement, the unlocking air circuit interface is connected to an air circuit with a certain air pressure. Under the action of the air pressure, the zero-point locator unlocks from the pull stud. At this time, the pull stud can move freely and realize the function of guiding the replacement of the electrode wire a. The unlocking air circuit interface is used to provide the air pressure source for unlocking the zero-point locator and the pull stud. When ventilated, the air pressure pushes the zero-point locator to unlock, and the pull stud can move freely. When closed, the zero-point locator fixes and clamps the pull stud. The central blowing air circuit interface is used to provide the air pressure source for central blowing. It is ventilated when the zero-point locator unlocks from the pull stud. Since the central anti-chip device at the zero-point locator releases the seal with the inner wall of the central hole of the zero-point locator during unlocking, it is necessary to introduce an air circuit to generate an air flow, which is blown out from the gap between the zero-point locator and the central anti-chip device at the zero-point locator to prevent impurities such as cutting fluid and chips from entering the internal part of the zero-point positioning system B along the gap between the zero-point locator and the central anti-chip device at the zero-point locator.

[0036] The present invention also provides a processing device A for the square hole of the valve sleeve of an electro-hydraulic servo valve, including an electrode wire a and an electrode wire b, a zero-point positioning system A, two positioning wheels b with the same shape and size, a fixture for the valve sleeve of the electro-hydraulic servo valve, and a wire electrical discharge machining machine tool.

[0037] The electrode wire a and the electrode wire b are wire-cutting wires in the wire electrical discharge machining technology and are used for processing the square hole of the valve sleeve of the electro-hydraulic servo valve. The diameter of the electrode wire a is larger than that of the electrode wire b.

[0038] The two positioning wheels b are used to replace the two positioning wheels a in the zero-point positioning system A to clamp the resistance wire b.

[0039] The fixture for the valve sleeve of the electro-hydraulic servo valve is used to clamp the valve sleeve of the electro-hydraulic servo valve, horizontally fix it above the wire electrical discharge machining machine tool, and at the same time is used to drive the valve sleeve of the electro-hydraulic servo valve to rotate around its own central axis. The valve sleeve of the electro-hydraulic servo valve is the part to be processed.

[0040] The zero-point positioning system A is fixedly connected to the moving platform of the wire electrical discharge machining machine tool (mainly realized by the cooperation of the mechanical structure of the base of the zero-point positioning system A and the moving platform of the wire electrical discharge machining machine tool), and the central axis of the pull stud is perpendicular to the moving platform of the wire electrical discharge machining machine tool.

[0041] The positioning wheels are used to determine the fixed positions of the electrode wires. Different-sized positioning wheels need to be configured for different-sized electrode wires to achieve precise fixing of their positions. In the present invention, two positioning wheels a are configured for electrode wire a, and two positioning wheels b are configured for electrode wire b. By replacing the positioning wheels, adaptation to different-sized electrode wires can be achieved without changing the position of the positioning pins. The present invention only needs to ensure the diameter precision of the positioning wheels to guarantee the overall positioning precision.

[0042] As a preferred technical solution:

[0043] For a processing device A for the square hole of the valve sleeve of an electro-hydraulic servo valve as described above, the fixture for the valve sleeve of the electro-hydraulic servo valve is a three-jaw chuck and a center. The three-jaw chuck is used to clamp and rotate the valve sleeve of the electro-hydraulic servo valve, and the center is used to position the valve sleeve of the electro-hydraulic servo valve to ensure the horizontal reference of the valve sleeve.

[0044] The present invention also provides a processing device B for the square hole of the valve sleeve of an electro-hydraulic servo valve, which includes electrode wire a and electrode wire b, zero-point positioning system B, two positioning wheels b with the same shape and size, two guide wheels b with the same shape and size, a fixture for the valve sleeve of the electro-hydraulic servo valve, and a wire electrical discharge machining machine;

[0045] Electrode wire a and electrode wire b are wire-cutting wires in the wire electrical discharge machining technology and are used for processing the square hole of the valve sleeve of the electro-hydraulic servo valve. The diameter of electrode wire a is larger than that of electrode wire b;

[0046] Two positioning wheels b are used to replace two positioning wheels a in the zero-point positioning system B to clamp resistance wire b; two guide wheels b are used to replace two guide wheels a in the zero-point positioning system B to clamp resistance wire b;

[0047] The fixture for the valve sleeve of the electro-hydraulic servo valve is used to clamp the valve sleeve of the electro-hydraulic servo valve, horizontally fix it above the wire electrical discharge machining machine, and at the same time is used to drive the valve sleeve of the electro-hydraulic servo valve to rotate around its own central axis. The valve sleeve of the electro-hydraulic servo valve is the part to be processed;

[0048] The zero-point positioning system B is fixedly connected to the moving platform of the wire electrical discharge machining machine (mainly achieved by the cooperation of the mechanical structure of the base of the zero-point positioning system B and the moving platform of the wire electrical discharge machining machine), and the central axis of the pull stud is perpendicular to the moving platform of the wire electrical discharge machining machine.

[0049] The positioning wheels are used to determine the fixed positions of the electrode wires. Different-sized positioning wheels need to be configured for different-sized electrode wires to achieve precise fixing of their positions. In the present invention, two positioning wheels a are configured for electrode wire a, and two positioning wheels b are configured for electrode wire b. By replacing the positioning wheels, adaptation to different-sized electrode wires can be achieved without changing the position of the positioning pins. The present invention only needs to ensure the diameter precision of the positioning wheels to guarantee the overall positioning precision.

[0050] As a preferred technical solution:

[0051] For a processing device B for the square hole of the valve sleeve of an electro-hydraulic servo valve as described above, the fixture for the valve sleeve of the electro-hydraulic servo valve is a three-jaw chuck and a center, the three-jaw chuck is used to clamp and rotate the valve sleeve of the electro-hydraulic servo valve, and the center is used to position the valve sleeve of the electro-hydraulic servo valve to ensure the horizontal reference of the valve sleeve.

[0052] The present invention also provides a processing method for the square hole of the valve sleeve of an electro-hydraulic servo valve using the above-described processing device A or processing device B, and the process includes: valve sleeve clamping → square hole processing → valve sleeve rotation → square hole processing;

[0053] Valve sleeve clamping means clamping the valve sleeve of the electro-hydraulic servo valve with the fixture for the valve sleeve of the electro-hydraulic servo valve and horizontally fixing it above the wire electrical discharge machining machine; the three-jaw chuck and the center are not connected to the table of the wire electrical discharge machining machine, are independently fixed and ensure that the position remains unchanged during the whole processing process, so as to ensure that the position of the valve sleeve remains unchanged during the whole processing process;

[0054] Valve sleeve rotation means driving the valve sleeve of the electro-hydraulic servo valve to rotate 90° around its own central axis by using the fixture for the valve sleeve of the electro-hydraulic servo valve;

[0055] The specific process of all square hole processing is as follows: first, use the zero-point positioning system A or B to guide the electrode wire a to process a group of square holes on the valve sleeve of the electro-hydraulic servo valve, and then use the zero-point positioning system A or B to guide the electrode wire b to finish machining the group of square holes. During the whole process, the zero-point positioning system A or B is driven by the wire electrical discharge machining machine to move; wherein, in the square hole processing, guiding the electrode wire a or the electrode wire b by the zero-point positioning system A or B means using the quick change function of the zero-point positioning system A or B to pass the electrode wire for wire electrical discharge machining through the zero-point positioning system A or B and fix the position (fix it at the center of the pull stud through the positioning wheel a or the positioning wheel b, and fix it at the center of the zero-point positioning system A or B through the cooperation of the pull stud and the zero-point locator), and then the pull stud guides the electrode wire a or the electrode wire b to pass through the valve sleeve of the electro-hydraulic servo valve to be processed, so as to realize the quick piercing of the electrode wire; the zero-point positioning system A or B is fixed to the moving platform of the wire electrical discharge machining machine through the zero-point positioning base, and through the cooperation of the pull stud and the zero-point locator in the zero-point positioning system A or B, the position of the pull stud is ensured to be fixed and unchanged, and further the position of the electrode wire guided by it is ensured to be unchanged, so as to realize the accurate machining of the electrode wire and eliminate the reference non-coincidence error caused by disassembly and replacement during the piercing of the electrode wire.

[0056] As a preferred technical solution:

[0057] For the processing method of the square hole of the valve sleeve of the electro-hydraulic servo valve as described above, the dimensional error of the square hole of the valve sleeve of the electro-hydraulic servo valve is within 0.001 mm, and the form and position error is within 0.005 mm.

[0058] Beneficial effects

[0059] (1) The zero-point positioning system of the present invention has a rapid tool change function, which shortens the wire cutting piercing and wire changing time and improves the processing efficiency;

[0060] (2) By using the positioning reference maintaining function of the zero-point positioning system, during the process of the electrode wire moving to machine another square hole after the machining of one square hole is completed, the positioning reference is kept unchanged, that is, the relative position between the electrode wire and the machining reference of the electro-hydraulic servo valve sleeve is ensured to be unchanged (the relative position being unchanged means that the position of the electrode wire before tool change is the same as that after tool change), eliminating the positioning error generated by multiple clampings in the traditional machining method and ensuring the high-precision machining of multiple square holes in one clamping. Description of the drawings

[0061] Figure 1 is a schematic diagram of the machining device for the square hole of the electro-hydraulic servo valve sleeve in the present invention;

[0062] Figure 2 is the internal structure diagram of the key part pull stud in the machining device for the square hole of the electro-hydraulic servo valve sleeve in the present invention;

[0063] Figure 3 is the process flow chart of the machining method for the square hole of the electro-hydraulic servo valve sleeve in the present invention;

[0064] Among them, 1 - electrode wire, 2 - electro-hydraulic servo valve sleeve, 3 - square hole of the electro-hydraulic servo valve sleeve, 4 - pull stud, 5 - zero-point positioning center chip protection device, 6 - zero-point locator, 7 - base, 8 - unlocking air circuit interface, 9 - central blowing air circuit interface, 10 - positioning wheel a, 11 - positioning wheel pin, 12 - guide wheel a, 13 - guide wheel pin, 14 - fastening bolt. Detailed implementation manners

[0065] The present invention will be further described below in conjunction with specific implementation manners. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0066] Embodiment 1

[0067] A zero-point positioning system B, as Figures 1 - 2 shown, includes a pull stud 4, a zero-point positioning center chip protection device 5, a zero-point locator 6 and a base 7;

[0068] The pull stud 4 is a complete rotary body structure composed of the cooperation of two semi-rotary body structures, and the two semi-rotary body structures are connected and fixed by a fastening bolt 14;

[0069] There is a wire threading hole in the center of the zero-point positioning system B for the electrode wire a to pass through. A partial length section of the wire threading hole is located within the pull stud 4, denoted as the L section; the diameter of the L section is 1.5 times the diameter of the electrode wire a.

[0070] There are two positioning wheels a 10 with the same shape and size, two positioning wheel pins 11 with the same shape and size, two guide wheels a 12 with the same shape and size, and two guide wheel pins 13 with the same shape and size within the pull stud 4.

[0071] The central axis of the L section coincides with the central axis of the pull stud 4.

[0072] The two positioning wheel pins 11 are symmetrically distributed on both sides of the central axis of the pull stud 4. The central axis of the positioning wheel pin 11 is perpendicular to the central axis of the pull stud 4. One end of the two positioning wheel pins 11 is fixedly connected to the same semi-rotary body structure, and the other end penetrates into the positioning hole on another semi-rotary body structure.

[0073] The two positioning wheels a 10 are respectively sleeved on the two positioning wheel pins 11 and are symmetrically distributed on both sides of the central axis of the pull stud 4. The positioning wheel a 10 is coaxially fitted with the positioning wheel pin 11, and the distance between the two positioning wheels a 10 is equal to the diameter of the electrode wire a.

[0074] There is a space for placing the two positioning wheels a 10 within the pull stud 4, and the size of this space enables the two positioning wheels a 10 to only rotate around their own central axes.

[0075] The two guide wheel pins 13 are symmetrically distributed on both sides of the central axis of the pull stud 4. The central axis of the guide wheel pin 13 is perpendicular to the central axis of the pull stud 4. One end of the two guide wheel pins 13 is fixedly connected to the same semi-rotary body structure, and the other end penetrates into the positioning hole on another semi-rotary body structure; one end of the two positioning wheel pins 11 and the two guide wheel pins 13 is fixedly connected to the same semi-rotary body structure.

[0076] The two guide wheels a 12 are respectively sleeved on the two guide wheel pins 13 and are symmetrically distributed on both sides of the central axis of the pull stud 4. The guide wheel a 12 is coaxially fitted with the guide wheel pin 13, and the distance between the two guide wheels a 12 is equal to the diameter of the electrode wire a.

[0077] There is a space for placing the two guide wheels a 12 within the pull stud 4, and the size of this space enables the two guide wheels a 12 to only rotate around their own central axes.

[0078] The two guide wheels a 12 and the two positioning wheels a 10 are arranged at intervals. The distance between the guide wheel a and the positioning wheel a is 1 / 3 of the length of the L section; the two guide wheels a 12 are closer to the entrance of the L section relative to the two positioning wheels a 10, and the distance between the guide wheel a and the entrance of the L section is 1 / 3 of the length of the L section.

[0079] The remaining length segment of the wire threading hole is located within the zero-point positioning center chip protection device 5, the zero-point locator 6, and the base 7. An unlocking air path interface 8 and a central blowing air path interface 9 for connecting the external air path and the zero-point locator 6 are provided on the base 7.

[0080] Embodiment 2

[0081] A zero-point positioning system A is basically the same as that in Embodiment 1, except that in Embodiment 2, there is no guide wheel a and guide wheel pin, and there is no space in the pull stud for placing two guide wheels a.

[0082] Embodiment 3

[0083] A processing device for the square hole of the valve sleeve of an electro-hydraulic servo valve, as Figures 1 - 2 shown, includes electrode wire a and electrode wire b (the electrode wire 1 shown in Figures 1 - 2 is one of them), the zero-point positioning system B of Embodiment 1, two positioning wheels b with the same shape and size, two guide wheels b with the same shape and size, an electro-hydraulic servo valve sleeve fixture, and a wire electrical discharge machining machine;

[0084] Electrode wire a and electrode wire b are wire-cutting wires in the wire electrical discharge machining technology, and the diameter of electrode wire a is larger than that of electrode wire b; the diameter of electrode wire a (the rough machining electrode wire for forming the square hole profile) is 0.16 mm, and the diameter of electrode wire b (the finish machining electrode wire for precision trimming the square hole profile) is 0.02 mm;

[0085] The two positioning wheels b are used to replace the two positioning wheels a 10 in the zero-point positioning system B to clamp the resistance wire b; the two guide wheels b are used to replace the two guide wheels a 12 in the zero-point positioning system B to clamp the resistance wire b;

[0086] The electro-hydraulic servo valve sleeve fixture is a three-jaw chuck and a center, which is used to clamp the electro-hydraulic servo valve sleeve 2, horizontally fix it above the wire electrical discharge machining machine, and at the same time is used to drive the electro-hydraulic servo valve sleeve 2 to rotate around its own central axis;

[0087] The zero-point positioning system B is fixedly connected to the moving platform of the wire electrical discharge machining machine, and the central axis of the pull stud 4 is perpendicular to the moving platform of the wire electrical discharge machining machine.

[0088] A processing method for the square hole of the electro-hydraulic servo valve sleeve using the processing device for the square hole of the electro-hydraulic servo valve sleeve as described above, as Figure 3 shown, the processing flow includes: valve sleeve clamping → square hole machining → valve sleeve rotation → square hole machining;

[0089] Valve sleeve clamping means using the electro-hydraulic servo valve sleeve fixture to clamp the electro-hydraulic servo valve sleeve 2 and horizontally fix it above the wire electrical discharge machining machine;

[0090] The rotation of the valve sleeve means that the valve sleeve fixture of the electro-hydraulic servo valve drives the valve sleeve 2 of the electro-hydraulic servo valve to rotate 90° around its own central axis;

[0091] The specific process of machining all the square holes is as follows: First, use the zero-point positioning system B to guide the electrode wire a to machine a group of square holes on the valve sleeve 2 of the electro-hydraulic servo valve, and then use the zero-point positioning system B to guide the electrode wire b to finish machining the group of square holes. During the whole process, the zero-point positioning system B is driven by the wire electrical discharge machining machine.

[0092] The dimensional error of the square holes of the manufactured valve sleeve of the electro-hydraulic servo valve is within 0.001 mm, and the form and position error is within 0.005 mm.

[0093] Example 4

[0094] A machining device for square holes of a valve sleeve of an electro-hydraulic servo valve includes an electrode wire a, an electrode wire b, the zero-point positioning system A of Example 2, two positioning wheels b with the same shape and size, a valve sleeve fixture of the electro-hydraulic servo valve, and a wire electrical discharge machining machine;

[0095] The electrode wire a and the electrode wire b are wire-cutting wires in the wire electrical discharge machining technology, and the diameter of the electrode wire a is larger than that of the electrode wire b; the diameter of the electrode wire a (coarse machining electrode wire, used for forming the square hole profile) is 0.16 mm, and the diameter of the electrode wire b (fine machining electrode wire, used for finishing the square hole profile) is 0.02 mm;

[0096] The two positioning wheels b are used to replace the two positioning wheels a in the zero-point positioning system A to clamp the resistance wire b;

[0097] The valve sleeve fixture of the electro-hydraulic servo valve is a three-jaw chuck and a center, which is used to clamp the valve sleeve of the electro-hydraulic servo valve, horizontally fix it above the wire electrical discharge machining machine, and at the same time is used to drive the valve sleeve of the electro-hydraulic servo valve to rotate around its own central axis;

[0098] The zero-point positioning system A is fixedly connected to the moving platform of the wire electrical discharge machining machine, and the central axis of the pull stud 4 is perpendicular to the moving platform of the wire electrical discharge machining machine.

[0099] The machining method for the square holes of the valve sleeve of the electro-hydraulic servo valve using the machining device for the square holes of the valve sleeve of the electro-hydraulic servo valve as described above includes: valve sleeve clamping → square hole machining → valve sleeve rotation → square hole machining;

[0100] Valve sleeve clamping means using the valve sleeve fixture of the electro-hydraulic servo valve to clamp the valve sleeve of the electro-hydraulic servo valve and horizontally fix it above the wire electrical discharge machining machine;

[0101] Valve sleeve rotation means using the valve sleeve fixture of the electro-hydraulic servo valve to drive the valve sleeve of the electro-hydraulic servo valve to rotate 90° around its own central axis;

[0102] The specific process of machining all the square holes is as follows: First, use the zero-point positioning system A to guide the electrode wire a to machine a group of square holes on the valve sleeve of the electro-hydraulic servo valve. Then, use the zero-point positioning system A to guide the electrode wire b to finish machining the group of square holes. During the whole process, the zero-point positioning system A is driven by the wire electrical discharge machining machine.

[0103] The dimensional error of the square holes on the valve sleeve of the electro-hydraulic servo valve obtained is within 0.001 mm, and the form and position error is within 0.005 mm.

[0104] It should be noted that the diameters of the electrode wire a and the electrode wire b in the present invention are not uniquely determined and can be replaced according to the actual production and machining conditions. The above Examples 3 and 4 only select a specific set of diameters of the electrode wire a and the electrode wire b for illustrative purposes, and do not represent that the diameters of the electrode wire a and the electrode wire b in the present invention must be set according to Examples 3 and 4. In addition, in the forming machining (rough machining) of the square hole profile and the finishing machining (finishing machining) of the square hole profile, it is not necessarily only one diameter of the electrode wire that is used, and multiple diameters of the electrode wire may be used.

Claims

1. A zero-point positioning system, comprising a pull stud (4), the pull stud (4) being a complete rotary body structure composed of the cooperation of two semi-rotary body structures, characterized in that, There is a wire threading hole in the center of the zero-point positioning system for the electrode wire a to pass through. A part of the length section of the wire threading hole is located inside the pull stud (4), denoted as the L section; there are two positioning wheels a (10) with the same shape and size and two positioning wheel pins (11) with the same shape and size inside the pull stud (4). The central axis of the L section coincides with the central axis of the pull stud (4). The two positioning wheel pins (11) are symmetrically distributed on both sides of the central axis of the pull stud (4). The central axis of the positioning wheel pin (11) is perpendicular to the central axis of the pull stud (4). One end of the two positioning wheel pins (11) is fixedly connected to the same semi-rotary body structure, and the other end penetrates into the positioning hole on the other semi-rotary body structure. The two positioning wheels a (10) are respectively sleeved on the two positioning wheel pins (11), and are symmetrically distributed on both sides of the central axis of the pull stud (4). The positioning wheel a (10) is coaxially fitted with the positioning wheel pin (11). The distance between the two positioning wheels a (10) is equal to the diameter of the electrode wire a. There is a space for placing the two positioning wheels a (10) inside the pull stud (4). The size of this space enables the two positioning wheels a (10) to only rotate around their own central axes.

2. The zero-point positioning system according to claim 1, characterized in that, There are also two guide wheels a (12) with the same shape and size and two guide wheel pins (13) with the same shape and size inside the pull stud (4). The two guide wheel pins (13) are symmetrically distributed on both sides of the central axis of the pull stud (4). The central axis of the guide wheel pin (13) is perpendicular to the central axis of the pull stud (4). One end of the two guide wheel pins (13) is fixedly connected to the same semi-rotary body structure, and the other end penetrates into the positioning hole on the other semi-rotary body structure. The two guide wheels a (12) are respectively sleeved on the two guide wheel pins (13), and are symmetrically distributed on both sides of the central axis of the pull stud (4). The guide wheel a (12) is coaxially fitted with the guide wheel pin (13). The distance between the two guide wheels a (12) is equal to the diameter of the electrode wire a. There is a space for placing the two guide wheels a (12) inside the pull stud (4). The size of this space enables the two guide wheels a (12) to only rotate around their own central axes. The two guide wheels a (12) and the two positioning wheels a (10) are arranged at intervals, and the two guide wheels a (12) are closer to the entrance of the L section than the two positioning wheels a (10).

3. A zero-point positioning system according to claim 2, wherein One end of the two positioning wheel pins (11) and the two guide wheel pins (13) is fixedly connected to the same semi-rotary body structure.

4. A zero-point positioning system according to claim 2, characterized in that, The distance between the guide wheel a and the positioning wheel a is 1 / 3 of the length of the L section; the distance between the guide wheel a and the entrance of the L section is 1 / 3 of the length of the L section.

5. A zero-point positioning system according to any one of claims 1 to 4, characterized in that, The diameter of the L section is 1.5 times the diameter of the electrode wire a.

6. A zero-point positioning system according to any one of claims 1 to 4, characterized in that The zero-point positioning system further includes a zero-point positioning center chip protection device (5), a zero-point locator (6) and a base (7). The remaining length section of the wire threading hole is located inside the zero-point positioning center chip protection device (5), the zero-point locator (6) and the base (7). There are an unlocking air path interface (8) and a central blowing air path interface (9) on the base (7) for connecting the external air path with the zero-point locator (6).

7. A processing device for a square hole of a valve sleeve of an electro-hydraulic servo valve, characterized in that, It includes electrode wire a and electrode wire b, the zero-point positioning system as described in Claim 1, two positioning wheels b with the same shape and size, a clamp for the sleeve of an electro-hydraulic servo valve, and a wire electrical discharge machining (WEDM) machine tool; Electrode wire a and electrode wire b are wire-cutting wires in the wire electrical discharge machining technology, and the diameter of electrode wire a is larger than that of electrode wire b; The two positioning wheels b are used to replace the two positioning wheels a (10) in the zero-point positioning system to clamp the resistance wire b; The clamp for the sleeve of an electro-hydraulic servo valve is used to clamp the sleeve of the electro-hydraulic servo valve, horizontally fix it above the wire electrical discharge machining machine tool, and at the same time drive the sleeve of the electro-hydraulic servo valve to rotate around its own central axis; The zero-point positioning system is fixedly connected to the moving platform of the wire electrical discharge machining machine tool, and the central axis of the pull stud (4) is perpendicular to the moving platform of the wire electrical discharge machining machine tool.

8. A processing device for a square hole of a valve sleeve of an electro-hydraulic servo valve, characterized in that, It includes electrode wire a and electrode wire b, the zero-point positioning system as described in any one of Claims 2 to 4, two positioning wheels b with the same shape and size, two guide wheels b with the same shape and size, a clamp for the sleeve of an electro-hydraulic servo valve, and a wire electrical discharge machining (WEDM) machine tool; Electrode wire a and electrode wire b are wire-cutting wires in the wire electrical discharge machining technology, and the diameter of electrode wire a is larger than that of electrode wire b; The two positioning wheels b are used to replace the two positioning wheels a (10) in the zero-point positioning system to clamp the resistance wire b; the two guide wheels b are used to replace the two guide wheels a (12) in the zero-point positioning system to clamp the resistance wire b; The clamp for the sleeve of an electro-hydraulic servo valve is used to clamp the sleeve of the electro-hydraulic servo valve, horizontally fix it above the wire electrical discharge machining machine tool, and at the same time drive the sleeve of the electro-hydraulic servo valve to rotate around its own central axis; The zero-point positioning system is fixedly connected to the moving platform of the wire electrical discharge machining machine tool, and the central axis of the pull stud (4) is perpendicular to the moving platform of the wire electrical discharge machining machine tool.

9. A machining method for the square hole of the valve sleeve of an electro-hydraulic servo valve using the machining device according to claim 7 or 8, characterized in that, The process includes: valve sleeve clamping → square hole machining → valve sleeve rotation → square hole machining; Valve sleeve clamping means using the clamp for the sleeve of an electro-hydraulic servo valve to clamp the sleeve of the electro-hydraulic servo valve and horizontally fix it above the wire electrical discharge machining machine tool; Valve sleeve rotation means using the clamp for the sleeve of an electro-hydraulic servo valve to drive the sleeve of the electro-hydraulic servo valve to rotate 90° around its own central axis; The specific process of all square hole machining is as follows: first, use the zero-point positioning system to guide electrode wire a to machine a group of square holes on the sleeve of the electro-hydraulic servo valve, and then use the zero-point positioning system to guide electrode wire b to finish machining the group of square holes. During the whole process, the zero-point positioning system is driven by the wire electrical discharge machining machine tool to move.

10. The machining method of the square hole of the valve sleeve of the electro-hydraulic servo valve according to claim 9, characterized in that, The dimensional error of the square holes on the sleeve of the electro-hydraulic servo valve is within 0.001 mm, and the form and position error is within 0.005 mm.

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