Electrochemical machining device and method for microstructure of inner wall of deep small hole

Abstract

The present application belongs to the technical field of electrolytic processing, and particularly relates to an electrolytic processing device and method for the inner wall microstructure of a deep small hole. The device comprises an electrolyte backflow tank, an electrolyte tank and an electrolytic processing main body. The electrolytic processing main body is used for the electrolytic processing of a workpiece in the electrolyte tank. The bottom of the electrolytic processing main body is provided with a double-layer tube electrode for the electrolytic processing of the micro small hole. The double-layer tube electrode comprises a metal inner tube and an insulating outer tube arranged coaxially. The electrolyte is input into the inner tube electrode, and compressed air is introduced into the insulating outer tube. The electrolyte is high-speed sprayed from the side wall aperture of the inner tube electrode, and at the same time, the compressed gas high-speed sprayed from the side wall aperture of the insulating outer tube forms a local air chamber, thereby providing a stable processing place for the electrolytic jet. Meanwhile, the high-localized flexible processing is performed by utilizing the characteristics of the flow field impact and the electric field concentration of the electrolytic jet processing.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrolytic machining, and particularly relates to an electrolytic machining device and method for the inner wall microstructure of a deep small hole. BACKGROUND

[0002] In the field of manufacturing aero-engine and gas turbine, the design and manufacture of turbine cooling structure has great significance for strengthening heat exchange effect and improving turbine temperature. As a new type of turbine cooling structure, the periodic microstructure arranged on the inner wall of the turbulent cooling hole can increase the heat exchange area and strengthen the cold gas disturbance, and is a hot and key research object for designing and manufacturing high-performance aero-engine and gas turbine.

[0003] The turbulent cooling hole, i.e. the deep small hole, refers to a hole with a hole diameter of 0.1 to 3.0 mm and a ratio of hole depth to diameter greater than 10. The hole has a small diameter, a large depth-diameter ratio, a special and various hole type, and is usually made of high-temperature alloy, which belongs to a typical difficult-to-machine material extreme size structure and brings severe challenges to the existing manufacturing technology. The traditional hole inner wall microstructure machining methods include laser honing, vibration-assisted cutting, extrusion-ploughing, high-speed liquid-filled spinning and drawing, etc. Due to the large size of the device, the difficulty in preparing the forming tool and the tool damage, etc., the methods are not suitable for the manufacturing process of the turbulent cooling hole. Since electrolytic machining has the characteristics of non-contact, no stress and wide tool electrode design space, scholars at home and abroad still generally regard it as a main breakthrough for realizing the manufacturing of the microstructure on the inner wall of the small hole.

[0004] The current electrolytic machining method for the turbulent cooling hole mainly adopts lateral liquid supply, i.e. the electrolyte flows through the deep small hole to be machined, and the microstructure is transferred on the inner wall of the hole by using a forming cathode. The mass transfer effect of the flow field of this method is poor, and as the machining gap continuously increases, the internal electric field distribution gradually disperses, the stray corrosion is enhanced, and the machining localization is weakened, which affects the machining precision and quality.

[0005] Electrolytic jet machining is to use a simple-shaped electrode (such as a tube electrode) or other special-shaped electrode as a tool cathode, and the electrolyte is sprayed from the inside of the cathode to impact the surface of the workpiece anode. With the scanning movement of the cathode, the tool anode is dissolved by electrochemical reaction to machine a certain shape and feature. The electrolytic jet machining has the characteristics of direct impact of flow field and concentrated restriction of electric field, and can realize high-localized material removal and efficient product removal, and is particularly suitable for precision machining of surface microstructure. However, in the face of the long and closed environment of the deep small hole, high-speed liquid jet will flood the internal space of the small hole and the jet liquid beam, so that the electrolytic jet machining with process advantages cannot be directly used for small hole internal machining.

[0006] Therefore, the application is provided. SUMMARY

[0007] In order to meet the needs of stronger mass transfer and better electric field limitation in the process of processing turbulent cooling holes, and solve the problems of electrolytic jet machining technology in deep and small hole environment, the application provides an electrolytic machining device and method for deep and small hole inner wall microstructure, which aims to form a local gas chamber by compressed gas to provide a stable processing place for electrolytic jet, and use the characteristics of electrolytic jet machining flow field impact and electric field concentration to perform high-locality flexible processing.

[0008] The basic idea of the technical scheme of the application is:

[0009] The application discloses an electrolytic machining device for deep and small hole inner wall microstructure, which comprises an electrolyte backflow tank, an electrolyte pump, an air pump, a power supply, an electrolyte tank and an electrolytic machining main body.

[0010] The electrolyte tank is provided with a workpiece; the workpiece is provided with a micro hole to be processed; the electrolytic machining main body is located directly above the workpiece and can move in the vertical or horizontal direction; the positive electrode of the power supply is connected to the workpiece, and the negative electrode of the power supply is connected to the electrolytic machining main body; the bottom of the electrolytic machining main body is provided with a double-layer tube electrode for electrolytic machining of the micro hole; the double-layer tube electrode comprises a metal inner tube and an insulating outer tube, which are coaxially arranged and sealed at the ends, and the inner tube electrode and the insulating outer tube are both provided with holes at the same position on the side wall; the electrolyte backflow tank inputs electrolyte into the inner tube electrode through the electrolyte pump; the air pump is used for inputting compressed air into the insulating outer tube; while the electrolyte is sprayed at high speed from the hole in the side wall of the inner tube electrode, the compressed gas sprayed at high speed from the hole in the side wall of the insulating outer tube is used to remove the electrolyte and electrolytic products accumulated in the deep and small hole, so that the inner wall surface of the small hole impacted by the jet is electrochemically dissolved; the movement of the main shaft and the Z-axis of the machine tool is combined to control the trajectory of the jet scanning the inner wall surface of the small hole, and the required microstructure is formed.

[0011] As a preferred technical scheme, the electrolytic machining main body comprises a rotating head, a rotating drive device, a metal inner tube chuck, a conductive copper base, a gas cavity and a guide; the rotating head is located at the hollow shaft center of the entire electrolytic machining main body and drives the double-layer tube electrode to rotate through the rotating drive device; the metal inner tube chuck is used to install the metal inner tube at the lower end of the rotating head and conduct electricity; the conductive copper base is installed on the outer side wall of the rotating head and is used to connect the negative electrode of the power supply; the rotating drive device comprises a rotating head pulley, a motor pulley and a motor, the motor drives the motor pulley to rotate, and the rotation of the rotating head is driven through the belt; the gas cavity is used to clamp the insulating outer tube and provide a compressed gas delivery inlet; the guide is installed at the lower end of the gas cavity and plays a guiding role for the insulating outer tube.

[0012] As a preferred technical scheme, the rotating head comprises a pipe joint and a rotating head shell, a hollow shaft, a water stop plug and a connecting rod; the pipe joint is used as an electrolyte delivery inlet and is connected with an electrolyte pump through a water pipe; the pipe joint is installed at the upper end of a copper conduit, and the lower end of the copper conduit enters the interior of the rotating head shell; the hollow shaft is arranged at the center of an electrolytic machining main body and is inserted into the interior of the copper conduit; the hollow shaft and the rotating head shell are sealed through a sealing ring; the inner side of a rotating head pulley is fixed with the bottom of the outer side of the hollow shaft, and the upper end of the connecting rod enters the interior of the hollow shaft; the bottom of the outer side of the connecting rod is in interference connection with a metal inner tube clamp; the top of the metal inner tube is sequentially penetrated through the inner holes of the metal inner tube clamp and the connecting rod from bottom to top, and the top of the metal inner tube is sealed by the water stop plug arranged in the hollow shaft.

[0013] As a preferred technical scheme, the interior of the hollow shaft is in a stepped structure, the water stop plug is located in the interior of the first stage shaft cavity at the lower end, the outer diameter of the water stop plug is the same as the inner diameter of the first stage shaft cavity, the inner diameter of the water stop plug is the same as the outer diameter of the metal inner tube; the upper end of the metal inner tube is inserted into the interior of the water stop plug, the lower end of the water stop plug is supported by the connecting rod and is pressed by a copper nut; the copper nut is fixed at the lower end of the hollow shaft through threads, and simultaneously presses the connecting rod and the water stop plug.

[0014] As a preferred technical scheme, the air cavity comprises a sleeve, a cavity and a sleeve base; the sleeve is installed at the lower end of the rotating head and is used for clamping an insulating outer tube; the sleeve is installed at the lower end of the copper nut through bolts on a sleeve mounting plate; a plurality of sleeve wall holes penetrating through the sleeve are arranged on the sleeve; the cavity is nested outside the sleeve and does not directly contact the sleeve, a pipe joint mounting hole on the cavity is a compressed gas delivery inlet; the sleeve base is sleeved on the insulating outer tube.

[0015] As a preferred technical scheme, the lower end of the sleeve has a channel, and the channel is in a three-stage stepped structure; the insulating outer tube is clamped at the lower end of the sleeve and penetrates to the uppermost stage channel; the sleeve base is installed at the lowermost threaded channel of the sleeve.

[0016] As a preferred technical scheme, the guide is installed at the middle position of the stepped channel of the sleeve, the inner diameter of the guide is larger than the outer diameter of the insulating outer tube, and the outer diameter of the guide is consistent with the middle stepped channel at the lower end of the sleeve.

[0017] As a preferred technical scheme, the cavity is nested outside the sleeve and is installed on a multi-hole plate of a machine tool through a cavity mounting plate and does not directly contact the sleeve; a penetrating pipe joint mounting hole is arranged at the center position of the side of the cavity so as to be connected with a gas pump pipeline; compressed gas enters the cavity through the pipe joint and fills the cavity, then enters the sleeve through the sleeve wall holes, and after filling the sleeve, enters the insulating outer tube and is sprayed out from the side wall holes of the insulating outer tube.

[0018] The application further discloses a working method of the electrolytic machining device for the microstructure of the inner wall of a deep and small hole.

[0019] S1, install the rotating head on the z-axis perforated plate of the machine tool;

[0020] S2, insert the metal inner tube into the water stop plug from the bottom, clamp the metal inner tube with the metal inner tube clamp, and fix it;

[0021] S3, install the sleeve on the lower end of the copper nut of the rotating head through the sleeve mounting plate;

[0022] S4, insert the insulating outer tube into the sleeve from the bottom, then put on the second O-ring, and tighten the sleeve base to fix the insulating outer tube;

[0023] S5, the cavity is sleeved on the outside of the sleeve from the bottom, and is fixed on the perforated plate of the machine tool through the cavity mounting plate;

[0024] S6, install the motor on the right side of the rotating head through the motor mounting plate;

[0025] S7, install the conductive copper base on the left side of the rotating head by bolts;

[0026] S8, the conductive copper base is connected to the negative pole of the power supply through wires, and the workpiece is connected to the positive pole of the power supply through wires;

[0027] S9, control the machine tool to move, and insert the insulating outer tube into the micro hole of the workpiece;

[0028] S10, during processing, start the electrolyte pump and the air pump, the electrolytic jet is stably formed in the local gas chamber formed by compressed gas, the electric field between the metal tube electrode and the inner wall of the deep small hole is constrained, and the compressed gas can quickly remove the electrolysis products in the processing area;

[0029] S11, turn on the power supply and the motor and set the parameters, the metal inner tube and the insulating outer tube rotate coaxially and reciprocate up and down at the same time, the electrolytic jet and the compressed gas move at the same time, under the action of the flow field impact and the electric field constraint characteristics of the electrolytic jet processing, the high localized flexible processing of the inner wall surface of the deep small hole with different hole diameters and different hole wall configurations is completed.

[0030] Compared with the prior art, the present application has the following advantages:

[0031] The present application has the following advantages: 1. By means of the local air chamber method, the compressed gas is used to drive away the electrolyte accumulated in the deep small hole, to form a local air chamber, to protect the stable formation of the electrolytic jet, to overcome the limitation that the electrolytic jet cannot adapt to the narrow semi-closed process environment of the deep small hole, and to stably introduce the electrolytic jet into the deep small hole. 2. The local air chamber can compress the liquid layer near the jet, limit the stray distribution of the electric field in the processing area, reduce stray corrosion, improve processing precision, and at the same time can quickly remove the electrolysis products in the processing area, and improve the mass transfer effect of the flow field. 3. The electric field constraint and flow field impact effect of the electrolytic jet can improve the localization and stability of the processing. 4. By adjusting the rotating speed of the inner tube electrode and the insulating outer tube, the feeding speed and the power supply parameters, a complex surface microstructure that cannot be achieved by traditional processing methods can be obtained, and flexible processing of the microstructure of the inner wall of the deep small hole can be realized.

[0032] The specific embodiments of the present application will be described in further detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a three-dimensional view of the electrolytic processing device for the microstructure of the inner wall of the deep small hole of the present application;

[0034] Figure 2 is a schematic diagram of the deep hole processing principle of the present application;

[0035] Figure 3 is a schematic diagram of the main structure of the electrolytic processing of the present application;

[0036] Figure 4 is a schematic diagram of the double-layer tube electrode structure of the present application;

[0037] Figure 5 is a sectional view of the rotating head of the present application;

[0038] Figure 6 is an enlarged schematic diagram of the metal inner tube of the present application;

[0039] Figure 7 is a local enlarged schematic diagram of the air cavity of the present application;

[0040] Figure 8 is an enlarged schematic diagram of the insulating outer tube of the present application.

[0041] Wherein the label name: I, rotating head, II, air cavity, 1, electrolyte backflow tank, 2, electrolyte pump, 3, air pump, 4, power supply, 5, workpiece, 6, electrolyte tank, 7, compressed gas, 8, electrolyte, 9, local air chamber, 10, sleeve base, 11, cavity, 12, cavity mounting plate, 13, sleeve mounting plate, 14, copper nut, 15, conductive copper base, 16, rotating head shell, 17, copper pipe, 18, pipe joint, 19, motor, 20, motor mounting plate, 21, belt, 22, metal inner tube, 23, metal inner tube side wall hole, 24, insulating outer tube side wall hole, 25, insulating outer tube, 26, metal inner tube clamp, 27, connecting rod, 28, rotating head pulley, 29, rotating head shell base, 30, first hollow bearing, 31, rubber washer, 32, second hollow bearing, 33, copper pipe base, 34, sealing ring, 35, hollow shaft, 36, metal washer, 37, water stop plug, 38, motor pulley, 39, sleeve, 40, pipe joint mounting hole, 41, sleeve wall hole, 42, first O-ring, 43, second O-ring, 44, guide, 45, cavity mounting hole. DETAILED DESCRIPTION

[0042] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments will be described clearly and completely below with reference to the drawings in the embodiments of the present application. The following embodiments are used to illustrate the present application.

[0043] As Figures 1-8 shown, the application discloses a kind of deep small hole inner wall microstructure's electrolytic machining device, including electrolyte backflow tank 1, electrolyte pump 2, air pump 3, power supply 4, electrolyte tank 6, electrolytic machining main body;

[0044] The workpiece 5 is arranged in the electrolyte tank 6; The workpiece 5 is provided with a micro-hole to be processed; The electrolytic machining main body is located directly above the workpiece 5, and can move in vertical or horizontal direction. The positive electrode of the power supply 4 is connected to the workpiece 5, and the negative electrode of the power supply 4 is connected to the conductive copper base 15 on the electrolytic machining main body, so as to provide power for the operation of the electrolytic machining main body; The bottom of the electrolytic machining main body is provided with a double-layer tube electrode for electrolytic machining of the micro-hole, the double-layer tube electrode includes a metal inner tube 22 and an insulating outer tube 25, which are coaxially arranged 35 and sealed at the end, and small holes are formed in the same position of the inner tube electrode and the insulating outer tube 25 side wall.

[0045] The electrolyte backflow tank 1 inputs electrolyte 8 into the inner tube electrode through electrolyte pump 2; the air pump 3 is used to input compressed air into the insulated outer tube 25; while the electrolyte 8 is sprayed at high speed from the small holes on the side wall of the inner tube electrode, the compressed gas 7 sprayed at high speed from the small holes on the side wall of the insulated outer tube 25 is used to remove the electrolyte 8 accumulated in the deep small holes, form a local air chamber 9, protect the stable formation of the electrolytic jet, thereby constrain the electric field between the metal inner tube 22 (cathode) and the inner wall of the small hole (anode), and quickly remove the electrolytic products in the processing area, so as to electrochemically dissolve the inner wall of the small hole impacted by the jet.

[0046] In addition to the conductive copper base 15 and the double-layer tube electrode, the electrolytic machining main body further comprises a rotating head I, a rotating drive device, a metal inner tube chuck 26, a gas cavity II and a guide 44.

[0047] The rotating head I is located in the hollow shaft 35 of the entire electrolytic machining main body, and drives the double-layer tube electrode to rotate through the rotating drive device.

[0048] The metal inner tube chuck 26 is used to install the metal inner tube 22 at the lower end of the rotating head I and conduct electricity.

[0049] The conductive copper base 15 is installed on the outer side wall of the rotating head I and is used to connect the negative electrode of the power supply 4.

[0050] The rotating drive device comprises a rotating head pulley 28, a motor pulley 38 and a motor 19. The motor 19 drives the motor pulley 38 to rotate, and drives the rotation of the rotating head I through the belt 21.

[0051] The gas cavity II is used to clamp the insulated outer tube 25 and provide a compressed gas 7 delivery inlet.

[0052] The guide 44 is installed at the lower end center of the sleeve 39 and plays a guiding role for the insulated outer tube 25.

[0053] The structure of the above components will be described in more detail as follows:

[0054] 1) Rotating head I:

[0055] The rotating head I comprises a pipe joint 18, a hollow shaft 35, a water stop plug 37, a rotating head shell 16, a connecting rod 27 and a copper nut 14. The pipe joint 18 is located at the upper end of the rotating head I and serves as an electrolyte 8 delivery inlet. The pipe joint 18 is installed at the upper end of the copper guide pipe 17, the lower end of the copper guide pipe 17 enters the inside of the rotating head shell 16, the hollow shaft 35 is inserted into the inside of the copper guide pipe 17, and the pipe joint 18 serves as the electrolyte 8 delivery inlet and is connected with the electrolyte pump 2 through a water pipe.

[0056] The hollow shaft 35 is arranged at the center of the electrolytic machining main body, and is sealed between the rotary head shell 16 and the hollow shaft 35 through the sealing ring 34; the inner side of the rotary head pulley 28 is fixed to the bottom of the outer side of the hollow shaft 35, and the upper end of the connecting rod 27 enters the inside of the hollow shaft 35; the bottom of the outer side of the connecting rod 27 is connected with the metal inner tube chuck 26 in an interference fit, the top of the metal inner tube 22 penetrates the inner holes of the metal inner tube chuck 26 and the connecting rod 27 from bottom to top in sequence, and the top of the metal inner tube 22 is sealed by the water stop plug 37 arranged in the hollow shaft 35; further, the inside of the hollow shaft 35 is a stepped structure, the water stop plug 37 is located in the first level shaft cavity at the lower end, the outer diameter of the water stop plug 37 is the same as the inner diameter of the first level shaft cavity, the inner diameter of the water stop plug 37 is the same as the outer diameter of the metal inner tube 22, and the water stop plug 37 plays a guiding role; when the metal inner tube 22 is installed, the upper end of the metal inner tube 22 is inserted into the inside of the water stop plug 37, and the water stop plug 37 plays a sealing role; the lower end of the water stop plug 37 is supported by the connecting rod 27 and is pressed by the copper nut 14. The copper nut 14 is fixed to the lower end of the hollow shaft 35 through threads, and simultaneously presses the connecting rod 27 and the water stop plug 37, thereby playing a sealing role.

[0057] 2) air cavity II:

[0058] The air cavity II includes the sleeve 39, the cavity body 11 and the sleeve base 10.

[0059] The sleeve 39 is installed at the lower end of the rotary head I and is used for clamping the insulating outer tube 25; the sleeve 39 is installed on the lower end of the copper nut 14 through bolts on the sleeve mounting plate 13; the lower end of the sleeve 39 has a hole, and the hole is a three-level stepped structure; the insulating outer tube 25 is clamped at the lower end of the sleeve 39, and the insulating outer tube 25 penetrates to the uppermost level hole; the inner diameter of the hole is only slightly larger than that of the insulating outer tube 25, thereby playing a guiding role; the sleeve 39 is provided with a plurality of sleeve wall holes 41 which are penetrated, so that the compressed gas 7 enters the sleeve 39 through the sleeve wall holes 41 and then enters the insulating outer tube 25.

[0060] The cavity body 11 is nested outside the sleeve 39 and does not directly contact the sleeve 39; the pipe joint mounting hole 40 on the cavity body 11 is the inlet for the compressed gas 7.

[0061] The sleeve base 10 is sleeved on the insulating outer tube 25 and is installed in the lowermost level threaded hole of the sleeve 39; the sleeve base 10 is fixed and pressed through threads, and simultaneously presses the second O-shaped ring 43, thereby playing a fixing role on the insulating outer tube 25; the inner hole diameter of the sleeve base 10 is slightly larger than the outer diameter of the insulating outer tube 25, thereby playing a guiding role.

[0062] 3) guider 44:

[0063] The guide 44 is installed in the middle of the stepped hole of the sleeve 39, and has a second O-ring 43 at each end to play a sealing role; the guide 44 is made of insulating medium, and its inner diameter is only slightly larger than the outer diameter of the insulating outer tube 25, and its outer diameter is basically consistent with the stepped hole in the middle of the lower end of the sleeve 39, so as to ensure the guiding effect on the insulating outer tube 25.

[0064] 4) the cavity 11:

[0065] The cavity 11 is nested outside the sleeve 39 and is bolted to the perforated plate of the machine tool through the cavity mounting plate 12, and does not directly contact the sleeve 39, and the two are sealed by the first O-ring 42; a through pipe joint mounting hole 40 is arranged at the center of the side surface of the cavity 11 to connect the pipe line of the air pump 3; the compressed gas 7 enters the cavity 11 through the pipe joint mounting hole 40 and fills the cavity 11, then enters the sleeve 39 through the sleeve wall hole 41, and after filling the sleeve 39, enters the insulating outer tube 25 and is sprayed out from the side wall hole 24 of the insulating outer tube 25.

[0066] The working method steps of the electrolytic machining device for the microstructure of the inner wall of the deep small hole of the application are as follows:

[0067] S1, the rotating head I is installed on the z-axis perforated plate of the machine tool through the mounting plate;

[0068] S2, the metal inner tube 22 is inserted into the water stop plug 37 from below, and the metal inner tube clamp 26 clamps the metal inner tube 22 to fix it;

[0069] S3, the sleeve 39 is installed at the lower end of the copper nut 14 of the rotating head I through the sleeve mounting plate 13;

[0070] S4, the insulating outer tube 25 is inserted into the sleeve 39 from below, and the second O-ring 43 is sleeved, and the sleeve base 10 is tightened to fix the insulating outer tube 25;

[0071] S5, the cavity 11 is sleeved outside the sleeve 39 from below, and is fixed on the perforated plate of the machine tool through the cavity mounting plate 12;

[0072] S6, the motor 19 is installed on the right side of the rotating head I through the mounting plate;

[0073] S7, the conductive copper base 15 is installed on the left side of the rotating head I through the bolt;

[0074] S8, the conductive copper base 15 is connected to the negative electrode of the power supply 4 through the wire, and the workpiece 5 is connected to the positive electrode of the power supply 4 through the wire;

[0075] S9, control the machine tool to move, and insert the insulating outer tube 25 into the small hole of the workpiece 5;

[0076] S10, when processing, start electrolyte pump 2 and air pump 3, electrolytic jet in the local gas chamber 9 formed by compressed gas 7 stable formation, the electric field between the metal tube electrode (cathode) and the inner wall of the deep small hole (anode) is constrained, and the compressed gas 7 can quickly remove the electrolysis products in the processing area;

[0077] S11, open power supply 4 and motor 19, set the parameters such as voltage, current, motor 19 speed, metal inner tube 22 and insulating outer tube 25 coaxial rotation and at the same time up and down reciprocating motion, electrolytic jet and compressed gas 7 move at the same time, under the action of electrolytic jet processing flow field impact and electric production constraint characteristics, complete the high domain flexible processing of different aperture, different hole wall configuration deep small hole inner wall surface.

[0078] Although the above has been described in detail with general description and specific embodiments, some modifications or improvements can be made on the basis of the present application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application, all belong to the scope of the present application.

Claims

1. An electrolytic machining device for the inner wall microstructure of a deep small hole, characterized in that: The electrolyte tank is provided with a workpiece, and the workpiece is provided with a micro-hole to be machined; the electrolytic machining main body is located directly above the workpiece and can move in the vertical or horizontal direction; the positive pole of the power supply is connected to the workpiece, and the negative pole of the power supply is connected to the electrolytic machining main body; the bottom of the electrolytic machining main body is provided with a double-layer tube electrode for electrolytic machining of the micro-hole, which comprises a metal inner tube and an insulating outer tube, and the two are coaxially arranged and sealed at the end; the same position of the side wall of the metal inner tube and the insulating outer tube is provided with a hole; the electrolyte tank inputs electrolyte into the metal inner tube through the electrolyte pump; the air pump is used to input compressed air into the insulating outer tube; while the electrolyte is sprayed at high speed from the hole in the side wall of the metal inner tube, the compressed gas sprayed at high speed from the hole in the side wall of the insulating outer tube is used to remove the electrolyte and electrolytic products accumulated in the deep micro-hole, so that the inner wall surface of the micro-hole impacted by the jet flow is electrochemically dissolved; the movement of the machine tool spindle and the Z-axis is combined to control the trajectory of the jet flow scanning the inner wall surface of the micro-hole, thereby forming the required microstructure. The electrolytic machining main body comprises a gas cavity, the gas cavity comprises a sleeve, a cavity and a sleeve base; the sleeve is installed at the lower end of the rotary head and used for clamping the insulating outer tube; a plurality of sleeve wall holes are provided on the sleeve; the cavity is nested outside the sleeve and does not directly contact the sleeve; a pipe joint mounting hole on the cavity is a compressed gas delivery inlet; the sleeve base is sleeved on the insulating outer tube. The electrolytic machining main body further comprises a rotary head, a rotary driving device, a metal inner tube chuck, a conductive copper base and a guide; the rotary head is located at the hollow shaft center of the entire electrolytic machining main body and drives the double-layer tube electrode to rotate through the rotary driving device; the metal inner tube chuck is used to install the metal inner tube at the lower end of the rotary head and conduct electricity; the conductive copper base is installed on the outer side wall of the rotary head and used to connect the negative pole of the power supply; the rotary driving device comprises a rotary head pulley, a motor pulley and a motor; the motor drives the motor pulley to rotate, and the rotation of the rotary head is driven through the belt; the gas cavity is used to clamp the insulating outer tube and provide a compressed gas delivery inlet; the guide is installed at the lower end of the gas cavity and plays a guiding role on the insulating outer tube.

2. The apparatus for electrochemical machining of the inner wall microstructure of a deep small hole according to claim 1, characterized in that: The rotary head comprises a pipe joint, a rotary head shell, a hollow shaft, a water stop plug and a connecting rod; the pipe joint serves as an electrolyte delivery inlet and is connected with the electrolyte pump through a water pipe; the pipe joint is installed at the upper end of a copper conduit, and the lower end of the copper conduit enters the inside of the rotary head shell; the hollow shaft is arranged at the center of the electrolytic machining main body and inserted into the inside of the copper conduit; the hollow shaft and the rotary head shell are sealed through a sealing ring; the inside of the rotary head pulley is fixed with the bottom of the outside of the hollow shaft, and the upper end of the connecting rod enters the inside of the hollow shaft; the bottom of the outside of the connecting rod is connected with the metal inner tube chuck in interference, and the top of the metal inner tube sequentially penetrates the inner holes of the metal inner tube chuck and the connecting rod from bottom to top, and the top of the metal inner tube is sealed by the water stop plug arranged in the hollow shaft.

3. The apparatus for electrochemical machining of the inner wall microstructure of a deep small hole according to claim 2, characterized in that: ​ 4. The apparatus for electrochemical machining of the microstructure of the inner wall of a deep small hole according to claim 3, characterized in that: The hollow shaft is internally stepped, the water stop plug is located in the first-stage shaft cavity at the lower end, the outer diameter of the water stop plug is the same as the inner diameter of the first-stage shaft cavity, the inner diameter of the water stop plug is the same as the outer diameter of the metal inner tube, the upper end of the metal inner tube is inserted into the water stop plug, the lower end of the water stop plug is supported by the connecting rod and is pressed by the copper nut, and the copper nut is fixed on the lower end of the hollow shaft through threads and simultaneously presses the connecting rod and the water stop plug.

5. The apparatus for electrochemical machining of the inner wall microstructure of a deep small hole according to claim 1, characterized in that: The sleeve lower end has a hole, the hole is a three-stage stepped structure, the insulating outer tube is clamped on the sleeve lower end and penetrates to the uppermost hole, and the sleeve base is installed on the lowermost threaded hole of the sleeve.

6. The apparatus for electrochemical machining of the inner wall microstructure of a deep small hole according to claim 2, characterized in that: The guide is installed at the middle position of the stepped hole of the sleeve, the inner diameter of the guide is larger than the outer diameter of the insulating outer tube, and the outer diameter of the guide is consistent with the middle stepped hole at the lower end of the sleeve.

7. The apparatus for electrochemical machining of the inner wall microstructure of a deep small hole according to claim 1, characterized in that: The cavity is nested outside the sleeve, is installed on the multi-hole plate of the machine tool through the cavity mounting plate and does not directly contact the sleeve, a through pipe joint mounting hole is arranged at the center position of the side of the cavity to connect the air pump pipeline, compressed gas enters the cavity through the pipe joint and fills the cavity, then enters the sleeve through the sleeve wall hole, fills the sleeve, and then enters the insulating outer tube and is sprayed out from the side wall hole of the insulating outer tube.

8. The working method of the electrolytic processing device of the inner wall microstructure of a deep small hole according to claim 1, characterized in that, The method comprises the following steps: S1, install the rotating head on the z-axis multi-hole plate of the machine tool; S2, insert the metal inner tube into the water stop plug from below, clamp the metal inner tube by the metal inner tube clamp to fix it; S3, install the sleeve on the lower end of the copper nut of the rotating head through the sleeve mounting plate; S4, insert the insulating outer tube into the sleeve from below, then put on the second O-shaped ring, and tighten the sleeve base to fix the insulating outer tube; S5, nest the cavity outside the sleeve from below, and fix it on the multi-hole plate of the machine tool through the cavity mounting plate; S6, install the motor on the right side of the rotating head through the motor mounting plate; S7, install the conductive copper base on the left side of the rotating head through the bolt; S8, connect the negative pole of the power supply to the conductive copper base through the wire, and connect the positive pole of the power supply to the workpiece through the wire; S9, control the machine tool to move and insert the insulating outer tube into the micro hole of the workpiece; S10, during processing, start the electrolyte pump and the air pump, the electrolytic jet is stably formed in the local gas chamber formed by the compressed gas, the electric field between the metal inner tube and the inner wall of the deep small hole is constrained, and the compressed gas can quickly remove the electrolysis products in the processing area; S11, turn on the power supply and the motor and set the parameters, rotate the metal inner tube and the insulating outer tube coaxially and simultaneously reciprocate up and down, and the electrolytic jet and the compressed gas move simultaneously, under the action of the flow field impact and electric field constraint characteristics of the electrolytic jet processing, the high-localized flexible processing of the inner wall surface of the deep small hole with different hole diameters and different hole wall configurations is completed.

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