A device and method for polishing and strengthening the inner surface of micro-holes with non-uniform cross-sections

Abstract

The invention discloses a device and method for polishing and strengthening the inner surface of micro-holes with non-uniform cross-sections. The device and method comprise a cross-shaped piston cylinder and a through-hole piston cylinder opposite thereto. A coil is wound around a piston four in the through-hole piston cylinder, and the inner surface of the micro-holes with non-uniform cross-sections is divided into a plurality of different regional bands along the axial direction according to the inner diameter size. The piston two performs regular reciprocating motion, and the moving distances of the piston one and the piston three toward the axial direction of the center of a workpiece to be processed are controlled to control the intensity of the cavitation effect in a closed space. The regional bands close to the through-hole piston cylinder are first polished and strengthened. After completion, the piston four pushes a magnetic fluid into the micro-holes with non-uniform cross-sections to fill the processed area and protect the area from excessive strengthening. The intensity of the cavitation effect in the closed space is then re-controlled, and the adjacent regional bands are polished and strengthened. The volume size of the closed space is continuously changed by the reciprocating motion of the piston, and the flowability and magnetic properties of the magnetic fluid are utilized to achieve uniform micro-hole polishing and strengthening effects.

Description

Technical Field

[0001] The invention relates to the field of polishing and strengthening processing, and in particular to a device that produces cavitation effect by volume alternation in a closed cavity, releases a large amount of energy and heat to polish and strengthen the inner surface of micropores. Background Art

[0002] With the rapid advancement of science and technology, the requirements for the precision and strength of mechanical parts have been increased, especially in the field of micro-holes and micro-deep holes. In some precision industries, such as military, aerospace, machinery, optoelectronics, civilian manufacturing and other cutting-edge products, precision micro-holes are processed on relatively thick metal materials. These micro-holes are not only stress concentration sites and fatigue weak sites of various components, but also often have burrs, which greatly affect the service life of various components and even directly affect the operation of the entire system. Therefore, micro-hole processing has always been called one of the most difficult manufacturing technologies. At present, optical etching, electric spark drilling, laser drilling, drilling platform drilling and other process methods are commonly used to process micro-holes, and the roughness of the inner surface of the micro-holes is large, and optical etching, laser processing and other methods will change the material properties of the inner surface of the micro-holes. In order to achieve the precision and strength requirements of the inner surface of the micro-holes, the inner surface of the micro-holes needs to be polished and strengthened, and the structural characteristics of micro-holes and deep holes make the inner surface of the micro-holes extremely difficult to process, especially for micro-holes with non-uniform cross-sections. Therefore, there is an urgent need for a device that can realize the polishing and strengthening of the inner surface of micro-holes with non-uniform cross-sections.

[0003] Polishing refers to a processing method that uses mechanical, chemical or electrochemical effects to reduce the surface roughness of a workpiece to obtain a bright and flat surface. Polishing cannot improve the dimensional accuracy or geometric shape accuracy of the workpiece, but is intended to obtain a smooth surface or mirror gloss, and is sometimes used to eliminate gloss (matte). At present, mechanical polishing, chemical polishing, electrolytic polishing, ultrasonic polishing, fluid polishing, magnetic grinding polishing and other methods are commonly used to polish the surface of workpieces. Mechanical polishing is a polishing method that obtains a smooth surface by removing tiny protrusions on the workpiece surface through cutting and plastic deformation of the material surface. Commonly used abrasive tools such as oilstone strips, wool wheels, and sandpaper are difficult to enter micropores with very small inner diameters, and are not suitable for polishing and strengthening the inner surface of micropores with non-uniform cross-sections; chemical polishing is to preferentially dissolve the microscopic protrusions on the surface of the material in a chemical medium to obtain a smooth surface. The solution used in this process is difficult to prepare and regenerate, and harmful gases are generated during the operation, which seriously pollutes the environment; the basic principle of electrolytic polishing is the same as that of chemical polishing, that is, the surface is smoothed by selectively dissolving materials to dissolve the tiny protrusions on the surface, but there are many parameters that affect electrolytic polishing, and it is not easy to find the correct electrolytic polishing parameters; ultrasonic polishing is to put the workpiece into an abrasive suspension and place it together in an ultrasonic field, relying on the oscillation of ultrasonic waves to grind and polish the abrasive on the workpiece surface. This method is difficult to install and install, and the equipment is expensive; magnetic grinding and polishing is to use magnetic abrasives to form abrasive brushes under the action of a magnetic field to grind the workpiece. This process is limited by the material of the workpiece and cannot process magnetic workpieces or workpieces that have been processed by a vibration grinder.

[0004] The cavitation effect refers to the phenomenon that tiny bubbles are generated inside a liquid under certain conditions, and the bubbles undergo a series of growth and development, and eventually collapse and collapse, generating huge energy and heat. For example, the enhanced polishing device disclosed in the document entitled "A Micropore Surface Enhanced Polishing Device and Method" with the Chinese patent publication number CN110116363B includes a workbench part, a cylinder part, a piston part, a clamping device part, and a power device part. The workpiece is fixed on the workbench by the clamping device, docked with the cylinder part and injected with appropriate liquid, and the piston part and the cylinder are matched to form a closed space. The piston part reciprocates in the closed space through the driving force given by the power device part, changing the volume of the closed space to control the pressure intensity in the closed space, thereby generating a cavitation effect and releasing a large amount of energy to polish and enhance the inner surface of the micropores; however, the collective collapse area of ​​the bubbles generated by the device is concentrated in the upper half of the workpiece, which easily leads to uneven polishing effect on the inner surface of the micropores. The cavitation shot peening equipment disclosed in the document with Chinese patent publication number CN110129537B and titled "A pressure-alternating micropore inner surface cavitation shot peening equipment and working method" controls the internal pressure of the closed chamber by changing the liquid volume in the closed chamber by controlling the rotation of the motor, controls the generation of the cavitation effect and the collapse of air bubbles, and uses the shock wave and high-speed water jet generated by the collapse of air bubbles to perform shot peening strengthening treatment on the inner surface of the micropore; however, when the equipment is used to process micropores of non-uniform cross-section, it is easy to cause different polishing and strengthening effects on both sides of the micropore, resulting in uneven strengthening effect on the inner surface of the micropore. The cavitation water jet enhancement device proposed in the document with Chinese patent application number 202210972594.7 and name “A device and method for actively controlling cavitation water jet to enhance the inner surface of micropores” controls the direction of the water jet by controlling four pistons in different directions respectively, and enhances and polishes the inner surface of the micropores. The device realizes variable nozzle outlet diameter, shape and outlet pressure through the degree of closure of the cross-shaped through-hole piston in different directions, actively controls the stroke and direction of the cavitation initiation, development, shedding and collapse stages in the water jet, changes the water flow carrying the cavitation, and changes the inner surface of the micropores. The pressure is controlled to control the travel length and direction of cavitation collapse at the front and rear ends of the micropore inner surface, change the collapse area and collapse direction of the cavitation at the front and rear ends of the micropore inner surface, and realize the strengthening of different areas and directions of the micropore inner surface; however, when the device processes the inner surface of micropores with non-uniform cross-sections, since the cavitations in the unequal cross-section parts will collide with the small cross-section wall in advance to generate energy, inducing other cavitations to collapse before reaching the wall, the cavitation group will collapse in the form of circular blocks on the inner surface of the micropore with the water jet, and the gaps between the blocks are difficult to completely cover, resulting in uneven polishing and strengthening effect on the inner surface of micropores with non-uniform cross-sections. Summary of the invention

[0005] The purpose of the present invention is to solve the problems existing in the prior art of being limited by the aspect ratio of micropores, low machining surface accuracy, uneven strengthening effect on both sides of the inner surface of micropores with non-uniform cross-sections, and not being suitable for polishing and strengthening the inner surface of micropores with non-uniform cross-sections, and to propose a controllable, uniformly strengthened, low-cost, and highly adaptable device for polishing and strengthening the inner surface of micropores with non-uniform cross-sections, and at the same time propose a polishing and strengthening method for the device.

[0006] In order to achieve the above-mentioned purpose, the technical solution adopted by the device for polishing and strengthening the inner surface of micro-holes with non-uniform cross-sections of the present invention is:

[0007] The technical scheme adopted by the method for polishing and strengthening the inner surface of a non-uniform cross-section micro-hole of the present invention is as follows: a cross-shaped piston cylinder is included, and the cross-shaped piston cylinder is composed of a piston cylinder 1, a piston cylinder 2 and a piston cylinder 3 which are all arranged horizontally. The central axes of the piston cylinder 1 and the piston cylinder 3 are collinear, and are respectively located on both sides of the piston cylinder 2 and are arranged symmetrically with respect to the central axis of the piston cylinder 2; the cross-shaped piston cylinder is directly opposite to the through-hole piston cylinder, and the central axis of the through-hole piston cylinder is collinear with the central axis of the piston cylinder 2; a workpiece to be processed is arranged between the piston cylinder 2 and the through-hole piston cylinder; a piston is sealed and slidably connected inside each of the piston cylinders 1, 2, 3 and the through-hole piston cylinder, They are piston one, piston two, piston three and piston four, forming a closed cross-shaped rodless chamber inside the cross-shaped piston cylinder, a coil connected to an external power supply is wound around piston four; piston cylinder two is equipped with rubber sealing ring one at the cylinder mouth end close to the through-hole piston cylinder, and the through-hole piston cylinder is equipped with rubber sealing ring two at the cylinder mouth end of piston cylinder two, and the workpiece to be processed is tightly attached between rubber sealing ring one and rubber sealing ring two, so that the non-uniform cross-section tiny holes of the workpiece to be processed and the cross-shaped rodless chamber and the rodless chamber of the through-hole piston cylinder form a closed space together, and water and magnetic fluid are filled in the closed space, and the coil is energized, and the magnetic fluid is completely adsorbed on piston four.

[0008] Furthermore, the top of bracket one is fixedly connected to the cylinder side wall of the piston cylinder one through a horizontal double-headed threaded connecting rod one, and is fixedly connected to the cylinder side wall of the piston cylinder three through a horizontal double-headed threaded connecting rod two. The bottom of bracket one is vertically fixedly connected to a horizontal base, and the central axes of the double-headed threaded connecting rod one and the double-headed threaded connecting rod two are parallel to the central axis of the piston cylinder two.

[0009] Furthermore, the structures of piston cylinder one and piston cylinder three are the same, and the axial length of piston cylinder two is greater than the axial lengths of piston cylinder one and piston cylinder three.

[0010] Furthermore, the large end of the non-uniform cross-section micro-hole is sealed with the piston cylinder, and the small end is sealed with the through-hole piston cylinder.

[0011] The technical solution adopted by the method for polishing and strengthening the inner surface of the micropores with non-uniform cross-sections of the present invention includes:

[0012] The inner surface of the non-uniform cross-section micro-hole is divided into a plurality of different zone zones along the axial direction according to the inner diameter;

[0013] The second piston performs regular reciprocating motion in the second piston cylinder, and the moving distance of the first piston and the third piston toward the central axis of the workpiece to be processed is controlled to control the intensity of the cavitation effect in the enclosed space;

[0014] First, polish and strengthen the area near the through-hole piston cylinder. After completion, push the piston four, which moves toward the part to be processed, so that the magnetic fluid enters the micro-holes with non-uniform cross-sections and fills the processed area.

[0015] Then the intensity of the cavitation effect in the enclosed space is controlled again, and the adjacent zone is polished and strengthened; after completion, the piston 4 continues to push the magnetic fluid into the non-uniform cross-section micro-holes for filling;

[0016] This cycle is repeated until the entire inner surface of the non-uniform cross-section micro-hole is polished and strengthened.

[0017] Furthermore, when piston two continues to advance from the farthest end away from the workpiece to be processed toward the workpiece to be processed, the distance between piston one and piston three is the largest, and the area closest to the through-hole piston cylinder is polished and strengthened.

[0018] Furthermore, piston one and piston three are driven to move toward opposite sides at the same time, so that the volume of the rodless chamber of piston cylinder one and piston cylinder three is reduced, and piston two moves away from the workpiece to be processed, polishing and strengthening the adjacent area bands, and pushing the magnetic fluid to fill the adjacent area bands.

[0019] Furthermore, piston one and piston three are driven to move toward opposite sides simultaneously until the distance between piston one and piston three is equal to the inner diameter of piston cylinder two, and the area closest to the cross-shaped piston cylinder is polished and strengthened.

[0020] Compared with the prior art, the present invention has the following outstanding beneficial effects:

[0021] (1) The present invention is based on the cavitation principle. Through the reciprocating motion of the piston, the volume of the closed container is controlled to change regularly, and the volume of the closed space is continuously changed. When the volume of the sealed space increases, the pressure of the sealed liquid will decrease to below the saturated vapor pressure of the liquid, forming a low-pressure environment lower than the saturated vapor pressure of the liquid phase. In the low-pressure environment, gas nuclei in the liquid are precipitated to generate gas cavitation bubbles; then high pressure is generated through volume extrusion, the volume of the closed space is reduced, and the pressure of the sealed liquid is increased, which causes the gas cavitation bubbles to collapse and burst, and the cavitation bubbles to rupture; due to the alternating changes in the volume in the closed container, cavitation bubbles are continuously generated and burst, and the rupture of the cavitation bubbles will generate extremely huge energy, thereby realizing the use of the shock wave and high-speed microflow generated by the cavitation bubble collapse energy to polish and strengthen the inner surface of the micropores.

[0022] (2) The present invention utilizes the cavitation impact generated when air bubbles collapse during the cavitation effect to flexibly "hammer" the inner surface of micropores with non-uniform cross-sections. This can achieve better surface quality, smaller surface roughness value, and more continuous and smooth material surface contour than traditional polishing. In addition, it can effectively reduce harmful deformations such as sharp edges and microcracks on the material surface, thereby further improving the comprehensive performance of the material.

[0023] (3) The present invention divides the inner surface of the non-uniform cross-section micropores into different areas according to the pore size, controls the two pistons to push forward toward the axis of the workpiece, thereby controlling the cavitation intensity, and controlling the bubble groups to form tubular collapse zones in different areas of the inner surface of the micropores. The inner surface of the non-uniform cross-section micropores is polished and strengthened in stages to prevent problems such as excessive strengthening of one side of the inner surface of the micropores or incomplete strengthening of one side.

[0024] (4) The present invention utilizes the flowability and magnetic properties of magnetic fluid to fill the processed area on the inner surface of the non-uniform cross-section micropores, protect the area from excessive strengthening, and polish and strengthen different axial areas of the non-uniform cross-section micropores by cooperating with two pistons, so that the micropore polishing and strengthening effects are uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments:

[0026] Figure 1 It is a schematic structural diagram of a device for polishing and strengthening the inner surface of micro-holes with non-uniform cross-sections according to the present invention;

[0027] Figure 2 for Figure 1 A magnified cross-sectional view of the structure of the middle double-threaded connecting rod 1;

[0028] Figure 3 for Figure 1 The structural exploded and enlarged diagram of the middle clamping through-hole piston cylinder;

[0029] Figure 4for Figure 1 A magnified top view of the cross-shaped piston cylinder;

[0030] Figure 5 for Figure 1 A magnified cross-sectional view of the internal structure of the through-hole piston cylinder;

[0031] Figure 6 for Figure 1 A schematic diagram of the internal structure principle of the cross-shaped piston cylinder and the through-hole piston cylinder of the device shown in the initial state;

[0032] Figure 7 for Figure 1 A schematic diagram of the internal structure principle of the cross-shaped piston cylinder and the through-hole piston cylinder when the device shown is working in the intermediate state;

[0033] Explanation of the reference numerals: 1. Base; 2. Piston 1; 3. Bracket 1; 4. Double-threaded connecting rod 1; 5. Piston cylinder 1; 6. Piston 2; 7. Piston cylinder 2; 8. Double-threaded connecting rod 2; 9. Piston cylinder 3; 10. Piston 3; 11. Rubber sealing ring 1; 12. Rubber sealing ring 2; 13. Piston cylinder sleeve; 14. Sealing plug 1; 15. Through-hole piston cylinder; 16. Coil; 17. Piston 4; 18. Bracket 2; 19. Screw; 20. T-shaped boss; 21. Right-handed external thread; 22. Right-handed internal thread; 23. Left-handed internal thread; 24. Left-handed external thread; 25. Sealing plug 2; 26. Water injection hole; 27. Water outlet; 28. Internally threaded hole; 29. ​​T-shaped groove; 30. Workpiece to be processed; 31. Magnetic fluid. DETAILED DESCRIPTION

[0034] See also Figure 1 The present invention discloses a device for polishing and strengthening the inner surface of micro-holes with non-uniform cross-sections, which includes a cross-shaped piston cylinder and a through-hole piston cylinder 15 located directly opposite the cross-shaped piston cylinder. The cross-shaped piston cylinder is composed of piston cylinder 15, piston cylinder 27 and piston cylinder 39, which are all arranged horizontally, wherein the central axes of piston cylinder 15 and piston cylinder 39 are collinear, i.e., in the Y-axis direction. Piston cylinder 15 and piston cylinder 39 have the same structure, and are respectively located on both sides of piston cylinder 27, and are symmetrically arranged relative to the central axis of piston cylinder 27. Piston cylinder 27, piston cylinder 15 and piston cylinder 39 have the same height, and the central axis of piston cylinder 27 intersects vertically on the same horizontal plane as the central axes of piston cylinder 15 and piston cylinder 39. The central axis of piston cylinder 27 is collinear with the central axis of through-hole piston cylinder 15, i.e., in the X-axis direction, and a gap is left between piston cylinder 27 and through-hole piston cylinder 15 for installing a workpiece 30 to be processed, and the workpiece 30 to be processed fits tightly with piston cylinder 27 and through-hole piston cylinder 15, see Figure 6 .

[0035] The cross-shaped piston cylinder is clamped by its corresponding clamp and connected to the horizontal base 1 through the clamp, and the base 1 is parallel to the XY plane; the through-hole piston cylinder 15 is also clamped by its corresponding clamp and connected to the horizontal base 1 through the clamp.

[0036] The fixture for holding the cross-shaped piston cylinder can fix the cross-shaped piston cylinder on the one hand, and can drive the cross-shaped piston cylinder as a whole to move back and forth along the direction of the central axis of the piston cylinder 27 on the other hand. The fixture includes a bracket 13 and two double-threaded connecting rods. The bottom of the bracket 13 is vertically fixedly connected to the upper surface of the base 1, and the vertical direction is the Z-axis direction. The top of the bracket 13 has two branches, which are connected to two double-threaded connecting rods, namely, double-threaded connecting rod 14 and double-threaded connecting rod 28. Double-threaded connecting rod 14 and double-threaded connecting rod 28 are distributed on both sides of the piston cylinder 27. The central axes of the double-threaded connecting rod 14 and double-threaded connecting rod 28 are parallel to the central axis of the piston cylinder 27, and the three are at the same height. The top of the bracket 13 is fixedly connected to the cylinder body side wall of the piston cylinder 15 through the double-threaded connecting rod 14, and is fixedly connected to the cylinder body side wall of the piston cylinder 39 through the double-threaded connecting rod 28.

[0037] See also Figure 2 As shown, the double-threaded connecting rod 14 and the double-threaded connecting rod 28 have the same structure. Take the double-threaded connecting rod 14 as an example: one end of the double-threaded connecting rod 14 is processed with a right-handed internal thread 22, and the other end is processed with a left-handed internal thread 23. The right-handed internal thread 22 matches the right-handed external thread 21 processed on the top of the bracket 3, and the left-handed internal thread 23 matches the left-handed external thread 24 extending from the side wall of the cylinder body of the piston cylinder 15. The internal threads at both ends of the double-threaded connecting rod 14 are rotated in opposite directions. When the double-threaded connecting rod 14 is rotated, the right-handed external thread 21 and the left-handed external thread 24 matched therewith move in the direction of tightening or dismantling at the same time, so that the piston cylinder 15 and the piston cylinder 3 9 move back and forth along the central axis direction of the piston cylinder 2 7, thereby driving the entire cross-shaped piston cylinder to move toward or away from the position of the through-hole piston cylinder 15.

[0038] See also Figure 3 As shown, the fixture for clamping the through-hole piston cylinder 15 includes a bracket 2 18 and a T-shaped boss 20. Two T-shaped bosses 20 are fixedly installed on the upper surface of the base 1. The length direction of the T-shaped boss 20 is consistent with the central axis direction of the through-hole piston cylinder 15. The top of the bracket 2 18 is fixedly connected to the through-hole piston cylinder 15, and two parallel T-shaped grooves 29 are set at the bottom, which respectively match the two T-shaped bosses 20. A horizontal internal thread hole 28 is set at the T-shaped groove 29, and the bracket 2 18 and the T-shaped boss 20 are fixed together by screws matching the internal thread 3 28. When the screws are loosened, the bracket 2 18 can move back and forth along the T-shaped boss 20, thereby driving the through-hole piston cylinder 15 away from or close to the piston cylinder 2 7.

[0039] See also Figure 1 The through-hole piston cylinder 15 is fixedly sleeved with a piston cylinder sleeve 13 on the outside near the second section of the piston cylinder. The top of the second bracket 18 is fixedly connected to the side wall of the piston cylinder sleeve 13, and the through-hole piston cylinder 15 is driven by the piston cylinder sleeve 13.

[0040] See also Figure 1 and Figure 4 , the axial length of piston cylinder 27 is greater than the axial length of piston cylinder 15 and piston cylinder 39. Piston cylinder 15 is sealed and slidably connected to piston 12, and the rod end of piston 12 extends outside piston cylinder 15 to connect to the first external drive component. Piston cylinder 27 is sealed and slidably connected to piston 26, and the rod end of piston 26 extends outside piston cylinder 27 and connects to the second external drive component. Similarly, piston cylinder 39 is sealed and slidably connected to piston 310, and the rod end of piston 310 extends outside piston cylinder 39 and connects to the third external drive component.

[0041] The rodless chambers of piston cylinder 2 7, piston cylinder 1 5 and piston cylinder 3 9 are interconnected to form a closed cross-shaped rodless chamber. Piston 1 2, piston 2 6 and piston 3 10 can all make regular reciprocating motions in the corresponding piston cylinders under the action of an external driving component to control the volume of the cross-shaped chamber.

[0042] The piston cylinder 27 is provided with a rubber seal ring 11 at the cylinder end near the through-hole piston cylinder 15, and the inner diameter of the rubber seal ring 11 is consistent with the inner diameter of the piston cylinder 27. When the workpiece 30 to be processed is tightly fitted between the piston cylinder 27 and the through-hole piston cylinder 15, the cross-shaped chamber is connected to the non-uniform cross-section micro-holes of the workpiece 30 to be processed through the rubber seal ring 11 to form a closed space.

[0043] See also Figure 1 and Figure 5 The through-hole piston cylinder 15 is sealed and slidably connected to the piston four 17, and the rod end of the piston four 17 extends out of the through-hole piston cylinder 15 and is connected to the fourth external drive component. The controller controls the four external drive components to work independently.

[0044] The through-hole piston cylinder 15 is provided with a rubber seal ring 12 at the cylinder end near the piston cylinder 7, and the inner diameter of the rubber seal ring 12 is consistent with the inner diameter of the through-hole piston cylinder 15. When the workpiece 30 to be processed is tightly fitted on the through-hole piston cylinder 15, the non-uniform cross-section micro-holes of the workpiece 30 to be processed are connected to the rodless cavity of the through-hole piston cylinder 15 through the rubber seal ring 11 to form a closed space.

[0045] The inner diameter of the rubber seal ring 11 and the piston cylinder 2 7 is consistent with the inner diameter of one end of the non-uniform cross-section micro-hole of the workpiece 30 to be processed, and the inner diameter of the rubber seal ring 2 12 and the through-hole piston cylinder 15 is consistent with the inner diameter of the other end of the non-uniform cross-section micro-hole of the workpiece 30 to be processed. In the present invention, the inner diameter of the rubber seal ring 11 and the piston cylinder 2 7 is larger than the inner diameter of the rubber seal ring 2 12 and the through-hole piston cylinder 15, so that the large end of the non-uniform cross-section micro-hole of the workpiece 30 to be processed between the piston cylinder 2 7 and the through-hole piston cylinder 15 is sealed and fitted with the piston cylinder 2 7, and the small end is sealed and fitted with the through-hole piston cylinder 15.

[0046] A water injection port 26 is provided on the upper side wall of the cylinder body of the through-hole piston cylinder 15, and a water outlet 27 is provided on the lower side wall. The water injection port 26 can inject water and magnetic fluid 31 into the rodless cavity of the through-hole piston cylinder 15, and the water in the rodless cavity can flow out through the water outlet 27. The water injection port 26 is tightly sealed by a sealing plug 14, and the water outlet 27 is tightly sealed by a sealing plug 25 to prevent gas from entering.

[0047] A coil 16 is wound around the piston 17, and the coil 16 is connected to an external power source, and can be energized to generate a magnetic field. Figure 6 and Figure 7 As shown, when the coil 16 is energized, the generated magnetic field tightly adsorbs the magnetic fluid 31 on the piston four 17. When the piston four 17 is pushed to move toward the piston cylinder two 7, the magnetic fluid 31 is pushed to enter the non-uniform cross-section micropores. As the processing of various areas on the inner surface of the micropores is completed, the magnetic fluid 31 fills the processed areas in the non-uniform cross-section micropores to protect the areas from being over-strengthened.

[0048] See also Figure 1-7 As shown, loosen the screw 19, adjust the bracket 2 18, and move the bracket 2 18 along the T-shaped boss 20 toward the opposite cross-shaped cylinder direction, clamp the workpiece 30 to be processed between the rubber seal ring 1 11 and the rubber seal ring 2 12, and adjust the two ends of the non-uniform cross-section micro-hole of the workpiece 30 to be processed to the same position as the piston cylinder 2 7 and the through-hole piston cylinder 15, so that the central axes of the non-uniform cross-section micro-hole, the piston cylinder 2 7, and the through-hole piston cylinder 15 are collinear. Then, rotate the double-headed threaded connecting rod 1 4 and the double-headed threaded connecting rod 2 8 at the same time and in the same direction, so that the workpiece 30 to be processed is clamped by the piston cylinder 2 7 and the through-hole piston cylinder 15.

[0049] The large-diameter end of the non-uniform cross-section micro-hole is matched with the piston cylinder 2 7, and the maximum diameter of the non-uniform cross-section micro-hole shall not be larger than the outer diameter of the rubber seal ring 1 1. The small-diameter end of the non-uniform cross-section micro-hole is matched with the through-hole piston cylinder 15, and the maximum diameter of the small-diameter end shall not be larger than the outer diameter of the rubber seal ring 2 12, ensuring that the space formed between the non-uniform cross-section micro-hole and the cross-shaped chamber and the through-hole piston cylinder 15 is sealed.

[0050] Water and magnetic fluid 31 in appropriate proportions are injected through the water injection port 26 so that the enclosed space formed by the cross-shaped chamber, the non-uniform cross-section micropores and the rodless cavity of the through-hole piston cylinder 15 is filled with water and magnetic fluid 31, and the water injection port 26 is sealed with a sealing plug 14.

[0051] The coil 16 is energized by an external power source, and a magnetic field is generated due to the electromagnetic effect, which causes the magnetic fluid 31 to flow toward the end of the piston 4 17 and is tightly adsorbed on the piston 4 17. At this time, the total volume of the magnetic fluid 31 should be equal to or slightly smaller than the volume of the rodless cavity of the piston cylinder 15, and there should be no magnetic fluid 31 in the micro-holes of non-uniform cross-section, so that the magnetic fluid 31 can quickly enter the micro-holes of non-uniform cross-section after being pushed.

[0052] Since the radial sections of the non-uniform cross-section micro-holes of the workpiece 30 to be processed are different, in order to achieve a uniform processing effect, the inner surface of the non-uniform cross-section micro-holes is divided into multiple different regional bands along the axial direction according to the inner diameter size, and the piston 2 6 performs regular reciprocating motion in the piston cylinder 2 7, and controls the movement distance of the piston 1 2 and the piston 3 10 to the center axis of the workpiece 30 to be processed to control the intensity of the cavitation effect in the closed space, so that the bubble group is squeezed to collapse in the different regional bands of the inner surface of the non-uniform cross-section micro-holes, and the micro-hole inner surface is strengthened and polished. First, the regional band close to the through-hole piston cylinder 15 is polished and strengthened, and after completion, the piston 4 17 is pushed, and the piston 4 17 moves toward the direction of the workpiece 30 to be processed, so that the magnetic fluid 31 adsorbed on the surface of the piston 4 17 enters the non-uniform cross-section micro-holes, fills the processed area, and prevents excessive strengthening of this part. Then the cavitation effect intensity in the enclosed space is controlled again, and the adjacent zone bands are polished; after completion, the piston 4 17 continues to push the magnetic fluid 31 into the non-uniform cross-section micro-holes for filling; this cycle is repeated until the polishing and strengthening of the entire non-uniform cross-section micro-hole inner surface is completed. The present invention is described as follows by taking the inner surface of the non-uniform cross-section micro-hole as an example of dividing the axial direction of the axial surface of the non-uniform cross-section micro-hole into three different zone bands according to the inner diameter size:

[0053] The external drive component is started to make the piston 26 perform regular reciprocating motion in the piston cylinder 27, and the volume of the enclosed space changes repeatedly. When the piston 26 moves away from the workpiece 30 to be processed, the volume of the enclosed space increases. Since the volume of the liquid remains unchanged, a negative pressure is formed in the enclosed space. When the pressure drops below the saturated vapor pressure of the liquid, the gas core in the liquid precipitates to form gas cavitation. As the volume continues to increase, the gas cavitation further develops and expands. When the piston 26 reaches the farthest end, the direction of the piston 26 is changed, and it begins to continuously move toward the workpiece 30 to be processed. The volume of the enclosed space begins to shrink, and the pressure rises. Under the squeeze of the liquid, the cavitation group collapses and collapses outward in a tubular shape with a central axis, generating a strong shock wave and a high-speed microjet to polish and strengthen the inner surface of the micropore. At this time, the distance between piston 1 2 and piston 3 10 is the largest, and they are located at the axis farthest from the workpiece 30 to be processed. When the volume changes, the liquid must pass through the rodless cavity of piston cylinder 1 5 and piston cylinder 3 9 where it is located, so the cavitation effect intensity is relatively low, resulting in the bubble group to be concentratedly collapsed in a tubular shape in the inner diameter range of the last section area near the through-hole piston cylinder 15 on the inner surface of the non-uniform cross-section micropore, and the rear section area near the through-hole piston cylinder 15 is strengthened. When the rear section area has been repeatedly strengthened and polished to achieve the desired effect, the piston 4 17 is pushed to move toward the opposite direction of the workpiece 30 to be processed. The piston 4 17 pushes the magnetic fluid 31 into the non-uniform cross-section micropore to fill the processed rear section area, and no longer strengthen this part.

[0054] The corresponding external drive components are started to drive the piston 1 2 and the piston 3 10 to move towards each other at the same time, and push in the direction of the central axis of the workpiece 30 to be processed, so that the volume of the rodless chamber of the piston cylinder 1 5 and the piston cylinder 3 9 is reduced. At this time, the piston 2 6 moves away from the workpiece 30 to be processed, and the distance of the movement of the piston 2 6 is slightly adjusted according to the positions of the piston 1 2, the piston 3 10 and the piston 4 17. At this time, due to the reduction of the volume of the rodless chamber of the piston cylinder 1 5 and the piston cylinder 3 9, the cavitation intensity in the closed space is enhanced, resulting in the cavitation bubble group generated by the volume change being concentratedly collapsed in the middle section of the inner surface of the non-uniform cross-section micropore in the form of a circular tube under the stronger squeezing of the liquid, so as to achieve the effect of polishing and strengthening the middle section of the non-uniform cross-section micropore.

[0055] When the enhanced polishing of the middle section of the non-uniform cross-section micro-holes reaches the desired effect, the piston 4 17 continues to be pushed to move toward the workpiece 30, pushing the magnetic fluid 31 to completely fill the processed middle section and rear section to prevent the middle section and rear section from being over-enhanced, thereby solving the problem of uneven strengthening of the inner surface of the micro-holes due to structural influence when the inner surface of the non-uniform cross-section micro-holes is polished and enhanced.

[0056] Continue to drive piston 1 2 and piston 3 10 to move in opposite directions at the same time, and push toward the central axis direction of the workpiece 30 to be processed, until the distance between piston 1 2 and piston 3 10 is equal to the inner diameter of piston cylinder 2 7, and the piston 1 2 and piston 3 10 are flush with the inner wall of piston cylinder 2 7, and the rodless cavity volume of piston cylinder 1 5 and piston cylinder 3 9 is zero. Piston 2 6 continues to move away from the workpiece 30 to be processed. At this time, the liquid does not need to flow through the two sides of the cross-shaped chamber, and the cavitation intensity in the closed space reaches the maximum, resulting in the cavitation group generated by the volume change to be concentratedly collapsed in a circular tube shape in the inner diameter range of the front section area of ​​the non-uniform cross-section micropore inner surface close to the cross-shaped piston cylinder under the strong squeezing pressure of the liquid, so as to achieve the effect of polishing and strengthening the front section area of ​​the non-uniform cross-section micropore, and the area closest to the cross-shaped piston cylinder does not need to be filled with magnetic fluid 31. In this way, the polishing and strengthening of the entire non-uniform cross-section micropore is completed.

[0057] After the processing is completed, the piston 4 17 is driven to reset, the coil 16 is powered off, the water outlet 27 is opened, and the water and magnetic fluid 31 are released. The double-ended threaded connecting rod 1 4 and the double-ended threaded connecting rod 2 8 are loosened, the workpiece 30 to be processed is removed, and the bracket 2 18 is adjusted to reset it.

[0058] This specific embodiment is only an explanation of the present invention, and it is not a limitation of the present invention. After reading this specification, those skilled in the art can make non-creative modifications to this embodiment as needed, but they are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A device for polishing and strengthening the inner surface of a micro hole with a non-uniform cross section, comprising a cross-shaped piston cylinder, characterized in that: The cross-shaped piston cylinder is composed of a piston cylinder 1 (5), a piston cylinder 2 (7) and a piston cylinder 3 (9) which are all arranged horizontally. The central axes of the piston cylinder 1 (5) and the piston cylinder 3 (9) are collinear, and are respectively located on both sides of the piston cylinder 2 (7) and are arranged symmetrically with respect to the central axis of the piston cylinder 2 (7). Opposite the cross-shaped piston cylinder is a through-hole piston cylinder (15), and the central axis of the through-hole piston cylinder (15) is collinear with the central axis of the piston cylinder 2 (7). A workpiece (30) to be processed is installed between the piston cylinder 2 (7) and the through-hole piston cylinder (15). The piston cylinder 1 (5), the piston cylinder 2 (7), the piston cylinder 3 (9) and the through-hole piston cylinder (15) are each sealed and slidably connected with a piston, namely, the piston 1 (2), the piston 2 (6), the piston 3 (10) and the piston 4 (11). 7), a closed cross-shaped rodless chamber is formed inside the cross-shaped piston cylinder, and a coil (16) connected to an external power supply is wound around the piston four (17); the piston cylinder two (7) is equipped with a rubber seal ring one (11) at the cylinder end close to the through-hole piston cylinder (15), and the through-hole piston cylinder (15) is equipped with a rubber seal ring two (12) at the cylinder end of the piston cylinder two (7), and the workpiece (30) to be processed is tightly attached between the rubber seal rings one and two (11, 12), so that the non-uniform cross-sectional micro-holes of the workpiece (30) to be processed and the cross-shaped rodless chamber and the rodless chamber of the through-hole piston cylinder (15) together form a closed space, and water and magnetic fluid (31) are filled in the closed space, and the coil (16) is energized, and the magnetic fluid (31) is completely adsorbed on the piston four (17); The top of the bracket one (3) is fixedly connected to the cylinder side wall of the piston cylinder one (5) through a horizontal double-threaded connecting rod one (4), and is fixedly connected to the cylinder side wall of the piston cylinder three (9) through a horizontal double-threaded connecting rod two (8). The bottom of the bracket one (3) is vertically fixedly connected to the horizontal base (1), and the central axes of the double-threaded connecting rod one (4) and the double-threaded connecting rod two (8) are parallel to the central axis of the piston cylinder two (7); The top of the second bracket (18) is fixedly connected to the through-hole piston cylinder (15), and a parallel T-shaped groove (29) is arranged at the bottom. A T-shaped boss (20) matching with the T-shaped groove (29) is arranged on the horizontal base (1), and the length direction of the T-shaped boss (20) is consistent with the central axis direction of the through-hole piston cylinder (15).

2. The device for polishing and strengthening the inner surface of micro-holes with non-uniform cross-sections according to claim 1 is characterized in that: The piston cylinder one (5) and the piston cylinder three (9) have the same structure, and the axial length of the piston cylinder two (7) is greater than the axial lengths of the piston cylinder one (5) and the piston cylinder three (9).

3. The device for polishing and strengthening the inner surface of micro-holes with non-uniform cross-sections according to claim 1 is characterized in that: The large end of the non-uniform cross-section micro-hole is sealed and fitted with the second piston cylinder (7), and the small end is sealed and fitted with the through-hole piston cylinder (15).

4. The device for polishing and strengthening the inner surface of micro-holes with non-uniform cross-sections according to claim 1 is characterized in that: A water inlet (26) is provided on the upper side wall of the cylinder body of the through-hole piston cylinder (15), and a water outlet (27) is provided on the lower side wall.

5. A polishing and strengthening method, using the non-uniform cross-section micro-hole inner surface polishing and strengthening device according to claim 1, characterized in that include: The inner surface of the non-uniform cross-section micro-hole is divided into a plurality of different zone zones along the axial direction according to the inner diameter; The second piston (6) performs regular reciprocating motion in the second piston cylinder (7), controlling the moving distance of the first piston (2) and the third piston (10) toward the central axis of the workpiece to be processed (30) to control the intensity of the cavitation effect in the enclosed space; First, the area near the through-hole piston cylinder (15) is polished and strengthened, and after completion, the piston four (17) is pushed, and the piston four (17) moves in the direction of the workpiece to be processed (30), so that the magnetic fluid (31) enters the micro-holes of non-uniform cross-section and fills the processed area; The intensity of the cavitation effect in the enclosed space is then controlled again to polish and strengthen the adjacent area bands; after completion, the piston four (17) continues to push the magnetic fluid (31) into the non-uniform cross-section micropores for filling; this cycle is repeated until the polishing and strengthening of the inner surface of the entire non-uniform cross-section micropore is completed.

6. The polishing and strengthening method according to claim 5, characterized in that: When the piston 2 (6) is continuously pushed from the farthest end away from the workpiece (30) to be processed toward the workpiece (30) to be processed, the distance between the piston 1 (2) and the piston 3 (10) is the largest, and the area closest to the through hole piston cylinder (15) is polished and strengthened.

7. The polishing and strengthening method according to claim 6, characterized in that: The driving piston 1 (2) and the piston 3 (10) are simultaneously moved toward opposite sides, so that the volume of the rodless chamber of the piston cylinder 1 (5) and the piston cylinder 3 (9) is reduced, and the piston 2 (6) moves away from the workpiece (30) to be processed, polishing and strengthening the adjacent area bands, and pushing the magnetic fluid (31) to fill the adjacent area bands.

8. The polishing and strengthening method according to claim 7, characterized in that: Continue to drive piston 1 (2) and piston 3 (10) to move towards opposite sides simultaneously until the distance between piston 1 (2) and piston 3 (10) is equal to the inner diameter of piston cylinder 2 (7) and the area closest to the cross-shaped piston cylinder is polished and strengthened.

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