Fluid polishing device and method for inner surface of elongated tube

Abstract

A fluid polishing device for the inner surface of an elongated tube, comprising a working platform (13), fluid processing units, and a magnetically controlled fluid unit. Two fluid processing units are provided, and are symmetrically mounted on the left side and the right side of the working platform (13); the left end and the right end of a workpiece (7) are respectively connected to the fluid processing units on the left side and the right side; the magnetically controlled fluid unit is located below the workpiece (7), and magnetic particles in a polishing solution in the fluid processing units are controlled by means of a magnetic field applied by a magnetic pole (11), so that the magnetic particles form, in a magnetic direction, a flux linkage having a certain yield strength, and are attracted on the inner surface of the workpiece (7) to form a local blocking block, thereby reducing the actual circulation diameter of the polishing solution in a blocked region, thus increasing the flow rate of the polishing solution, and improving the polishing strength. Also provided is a method using the polishing device. The polishing device and method can selectively polish regions of elongated tubes having an extremely fine diameter and an extremely large length-to-diameter ratio.

Description

Device and method for fluid polishing inner surface of slender tube Technical Field

[0001] The invention belongs to the field of fluid precision processing and relates to a device and method for polishing the fluid on the inner surface of a slender tube by using a magnetic field to control the fluid. Background Art

[0002] As modern high-end precision equipment tends to be miniaturized, slender tubular parts with small diameters and large aspect ratios are widely used in aerospace, biomedicine, chemical engineering and other fields, performing functions such as sample extraction, fluid transportation, and heat conduction and heat dissipation. In order to ensure the stability, accuracy and residue-free nature of sample extraction and fluid transportation, the inner surface of slender tubes must have a high degree of finish. At present, the processes for preparing slender tubular parts are mainly drawing and extrusion molding. When preparing small-diameter and variable-diameter tubes, wrinkles are inevitably generated on the inner surface, resulting in an inner surface roughness that does not meet industrial requirements and requires further polishing.

[0003] Currently, the main methods for polishing the inner surface of slender tubes are mechanical polishing, abrasive flow polishing, magnetic grinding, and electrolytic polishing. Mechanical polishing uses a tool head to penetrate the inner surface of the slender tube, but for slender tubes with a diameter of 1 mm or less, the tool has difficulty penetrating. Abrasive flow polishing uses high-pressure, high-viscosity non-Newtonian fluid for polishing, but the pressure inside the slender tube decays severely along the way, resulting in severely uneven polishing. Magnetic grinding uses magnets to drive magnetic particles inside the tube for polishing, but the magnetic particles cannot effectively and evenly cover the inner surface due to flow difficulties. Electrolytic polishing uses a redox reaction to dissolve the workpiece as the anode in the electrolyte, but the cathode has difficulty penetrating into the interior of the slender tube, making it difficult to avoid short circuits.

[0004] The existing patents related to polishing the inner surface of slender tubes are as follows:

[0005] Chinese patent CN102211295A proposes a magnetorheological polishing device for the inner surface of a capillary. This device uses a piston to inject magnetorheological fluid into the capillary and simultaneously activates a vibration drive system to vibrate the capillary, thereby increasing the fluidity of the magnetorheological fluid. After the capillary is completely filled with the magnetorheological fluid, an electromagnet is activated to generate a magnetic field, forming a cylindrical polishing mold within the capillary. This mold rotates around the capillary and moves along the capillary axis, polishing the inner surface of the capillary. Although this device introduces a magnetic field and magnetorheological fluid, it uses electromagnets to drive extremely small magnetic particles to grind the tube wall, resulting in extremely low polishing efficiency.

[0006] Chinese patent CN201455796U proposes a device for polishing the inner surface of a steel pipe, which can effectively polish the entire inner surface of the steel pipe. The device polishes the inner surface of the steel pipe using a polishing rope. The polishing rope passes through the steel pipe to be polished and is placed on a driving wheel and a driven wheel. The driving wheel is driven by a motor. A magnetic core is provided in the polishing rope, and a magnetic strip that can generate mutual attraction with the magnetic core is provided below the steel pipe to be polished. At the same time, the steel pipe rotates under the drive of the motor, thereby achieving the polishing process of the inner surface of the steel pipe. The device has a simple structure and obvious effect, but it uses a polishing rope for polishing, which has high requirements for the polishing rope and limited polishing effect. It cannot meet the polishing requirements for slender tubes with high inner surface quality requirements. At the same time, this method has high requirements for the aperture of the slender tube and is not suitable for polishing slender tubes with smaller apertures. Moreover, this method is difficult to use for slender tubes with poor rigidity, and it is impossible to keep the polishing rope in close contact with the inner surface of the slender tube.

[0007] Chinese patent CN202137643U proposes a magnetic polishing machine for the inner surface of a slender tube, which can quickly remove burrs, polish and clean the inner surfaces of various metal tubes and non-metallic tubes such as hard plastics. In this device, an iron core with a coil wrapped around it is arranged below and on the side of the non-magnetic slender tube. Alternating current is passed through the iron core to generate a reciprocating alternating magnetic field. Magnetic abrasive particles are placed in the tube cavity, and the magnetic abrasive particles are driven by the magnetic field generated by the iron core. At the same time, the electric motor drives the slender tube to rotate, thereby polishing its inner surface. This device can complete the polishing of inner surfaces that cannot be performed or cannot guarantee the processing quality of traditional technologies, but the coil generates severe heat after being energized, and there is a lack of corresponding heat dissipation measures; at the same time, the transmission wheel can only transmit large-diameter tubes, and this device is not suitable for processing small-diameter slender tubes.

[0008] Chinese patent CN110815027A proposes a device for polishing the inner hole of a slender tube, which has a simple structure and can be operated by one person. The device uses a flexible rod to connect the grinding head to the output end of the motor. The flexible rod is elastic. When the motor rotates, the end of the flexible rod connected to the grinding head swings circumferentially relative to the axis of the flexible rod, thereby polishing the inner surface of the slender tube. The polished tubes processed by this device have a high pass rate, low labor consumption, high polishing efficiency, and good polishing effect. However, for some slender tubes with smaller apertures, this method is limited by the size of the grinding head, and the grinding head cannot enter the interior of the slender tube, causing the method to fail.

[0009] Chinese patent CN206998477U proposes a polishing machine for the inner hole of a slender pipe. The device uses yarn to axially polish the inner hole of the workpiece. The yarn is clamped and fixed in sequence through a guide wheel, the inner hole of the workpiece, and a roller. The yarn drives the abrasive to move axially and radially relative to the inner hole of the workpiece, thereby polishing the inner hole. Although the yarn can enter a small inner hole, the abrasive driven by the yarn is very small and cannot effectively polish the inner hole surface.

[0010] The polishing tools of the above patents and other slender tube inner surface polishing devices are mostly polishing ropes and polishing rods, which cannot meet the polishing requirements of small-diameter slender holes. Therefore, it is urgent to provide a slender hole polishing device and method for smaller apertures to ensure polishing efficiency and polishing accuracy.

[0011] Summary of the Invention

[0012] In response to the problems existing in the current polishing schemes, the present invention aims to provide a fluid polishing device and method for the inner surface of a slender tube with magnetically controlled flow field scouring intensity, which can achieve rapid and uniform polishing of the inner surface of a straight tube, a variable diameter tube, and a variable roughness tube, thereby reducing the along-the-line resistance of the medium in the tube, improving sampling and injection accuracy, and enhancing the stability of the fluid in the tube, thereby solving the problems of limited, uneven and low efficiency in the existing polishing of the inner surface of a slender tube.

[0013] To achieve the above object, the present invention provides the following technical solutions:

[0014] A fluid polishing device for the inner surface of a slender tube includes a work platform, a fluid processing unit and a magnetic control fluid unit; there are two fluid processing units, which are symmetrically installed on the left and right sides of the work platform; the left and right ends of the slender tube, i.e. the workpiece, are respectively connected to the fluid processing units on the left and right sides.

[0015] The magnetic control fluid unit is located on the lower side of the workpiece. The magnetic field applied by the magnetic pole controls the magnetic particles in the polishing liquid in the fluid processing unit to form a magnetic chain with a certain yield strength along the direction of the magnetic force, which is adsorbed on the inner surface of the workpiece to form a local blockage, thereby reducing the actual flow diameter of the polishing liquid in the blocked area.

[0016] The fluid processing unit includes a piston, a piston cylinder, a piston rod, a rotating part, a connecting part and a piston cylinder bracket. The piston cylinder is fixedly connected to the work platform through the piston cylinder bracket, the inner end of the piston rod is fixedly connected to the piston, and the piston rod is slidably connected to the opening at the outer end of the piston cylinder; the piston is slidably connected to the inner surface of the piston cylinder, and polishing liquid is poured into the cavity between the inner side of the piston and the inner surface of the piston cylinder; the outlet of the inner end of the piston cylinder is connected to one end of the rotating part, and the other end of the rotating part is connected to the connecting part, and the other end of the connecting part clamps one end of the workpiece through an internal buckle.

[0017] The magnetron fluid unit comprises a magnet, a guide rail, a guide rail bracket, and a magnetic yoke. The guide rail bracket is located below the workpiece and fixedly connected to the workpiece platform. The guide rail is mounted on the guide rail bracket, with the axial direction of the guide rail parallel to the axial direction of the workpiece. The magnetic yoke is slidably connected to the guide rail. The magnet is fixed to the magnetic yoke. The distance between the magnet and the workpiece is 1-3 mm.

[0018] The rotating part includes a fixed section and a rotating section, the fixed section and the rotating section are connected through an internal bearing, the fixed section is connected to the piston cylinder, and the moving section is connected to the workpiece through a connecting piece.

[0019] Furthermore, there are three guide rails, which are installed at equal intervals in a plane parallel to the working platform.

[0020] Furthermore, there are two magnets, which have the same structure and are symmetrically installed on the yokes on the front and back sides of the workpiece. Each magnet includes a pole and a pole tip. The two magnets and the yoke form an isosceles triangle structure with an upper opening, and the distance between the pole tip and the workpiece is 1-3 mm.

[0021] Furthermore, the rotation speed of the workpiece is 6-20 revolutions per minute.

[0022] Furthermore, the magnet moves along the guide rail to perform magnetic control flow field polishing on each point on the axial direction of the inner surface of the workpiece.

[0023] Furthermore, the polishing medium in the polishing liquid is selected according to the workpiece material: cerium oxide is selected when the workpiece material is quartz glass, aluminum oxide is selected when the workpiece material is stainless steel, and diamond powder is selected when the workpiece material is cast iron.

[0024] A method for fluid polishing the inner surface of an elongated tube, comprising the following steps:

[0025] Step 1: Select appropriate polishing medium according to the workpiece material to prepare polishing liquid, stir the prepared polishing liquid evenly and then absorb it into the inner cavity of the piston cylinder.

[0026] Step 2: Connect the piston cylinder outlet to the rotating part and the connecting part through a threaded connection. The connecting part is connected to the two ends of the workpiece through its internal buckle. After the whole connection is completed, check the sealing.

[0027] Step 3: Place the magnet on the yoke so that the distance between the magnetic pole tip and the outer wall of the workpiece is 1-3 mm.

[0028] Step 4: Rotate the rotating part through an external transmission device to control the workpiece speed to 6-20 revolutions per minute.

[0029] Step 5: Use the external push rod to push the piston rods at both ends to move synchronously, ensuring that the polishing liquid is pushed out by the piston cylinder on one side while the polishing liquid is sucked into the piston cylinder on the other side. The polishing liquid flushes back and forth on the inner surface of the workpiece under the pushing action of the piston rod, thereby polishing the inner surface of the workpiece.

[0030] Step 6: Move the magnet along the guide rail to attract magnetic powder in different areas of the workpiece and adhere to the pipe wall to produce a blocking effect.

[0031] Step 7: After the processing is completed, stop the rotation, remove the workpiece, and put it into the ultrasonic cleaning machine for cleaning.

[0032] Step 8: The workpiece is inspected after processing, and its inner surface quality reaches the expected target, and the polishing process is completed.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] 1. The present invention uses magnets to adsorb magnetic particles in the magnetorheological polishing fluid flowing in the tube. The magnetic particles adhere to the tube wall to form regional magnetic blockages, causing the cross-sectional area of ​​the flow channel in this area to decrease. The flow velocity of the magnetic fluid containing polishing abrasives increases rapidly when passing through this area, thereby controllably changing the flow field intensity and polishing intensity in this area.

[0035] 2. The present invention utilizes a rotary joint to connect the relative rotation between the slender tube and the fixed polishing liquid delivery pipeline. The rotation of the slender tube ensures the uniformity of the inner surface area of ​​the selective polishing tube, while increasing the relative movement distance between the abrasive particles in the flushing fluid and the inner surface of the tube, thereby improving the removal efficiency.

[0036] 3. Compared with traditional fluid polishing, the present invention uses a magnetic field to selectively control polishing, completely resolving the problems of fluid pressure attenuation along the polishing process and uneven polishing. It also addresses the inability of traditional fluid polishing to polish thin tubes of varying diameters and varying roughness. Compared with traditional magnetic grinding, the use of a magnetic fluid polishing solution solves the problem of magnetic particles having difficulty penetrating small-diameter, thin tubes. Furthermore, because the present invention primarily uses polishing abrasive particles entrained by the flow field to perform polishing, varying degrees of material are removed from the entire inner surface of the thin tube, resulting in a polishing efficiency far superior to traditional magnetic grinding.

[0037] 4. In addition to magnetic abrasive particles, magnetic tools such as iron wire and magnetic needles can also be used to block the flow channel. Under the suction of the external magnet, these magnetic tools adhere tightly to the inner surface of the slender tube, not only blocking the flow field but also increasing the length of the blockage along the axial direction of the slender tube.

[0038] 5. In summary, the present invention is based on the fluidity of magnetorheological fluid and can realize the processing of slender tubes with extremely fine diameters and large aspect ratios, such as needle tubes with a length of >200 mm and an inner diameter of ≤1 mm. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG1 is a schematic structural diagram of the device of the present invention.

[0040] FIG2 is a cross-sectional view of a fluid processing unit according to the present invention (section lines are not shown).

[0041] FIG3 is a schematic diagram of a magnetron fluid unit of the present invention.

[0042] FIG4 is a cross-sectional view of FIG3 .

[0043] FIG5 is a partial enlarged view of FIG4 .

[0044] In the figure: 1. Piston rod; 2. Piston cylinder; 3. Piston cylinder bracket; 4. Piston; 5. Rotating part; 6. Connecting part; 7. Workpiece; 8. Guide rail bracket; 9. Guide rail; 10. yoke; 11. Magnetic pole; 12. Magnetic pole tip; 13. Working platform. DETAILED DESCRIPTION

[0045] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below with reference to the accompanying drawings. The description in this part is only exemplary and explanatory and should not have any limiting effect on the scope of protection of the present invention.

[0046] As shown in Figures 1-5, a fluid polishing device for the inner surface of an elongated tube includes a work platform 13, a fluid processing unit, and a magnetic control fluid unit. The fluid processing units are two and are symmetrically mounted on the left and right sides of the work platform 13. The left and right ends of the elongated tube, i.e., the workpiece 7, are connected to the fluid processing units on both sides, respectively.

[0047] The magnetic control fluid unit is located on the lower side of the workpiece 7. The magnetic field applied by the magnetic pole 11 controls the magnetic particles in the polishing liquid in the fluid processing unit to form a magnetic chain with a certain yield strength along the magnetic direction. The magnetic chain is adsorbed on the inner surface of the workpiece 7 to form a local blockage, thereby reducing the actual flow diameter of the polishing liquid in the blocked area.

[0048] The fluid processing unit includes a piston 4, a piston cylinder 2, a piston rod 1, a rotating member 5, a connecting member 6 and a piston cylinder bracket 3. The piston cylinder 2 is fixedly connected to the work platform 13 through the piston cylinder bracket 3. The inner end of the piston rod 1 is fixedly connected to the piston 4, and the piston rod 1 is slidably connected to the opening at the outer end of the piston cylinder 2; the piston 4 is slidably connected to the inner surface of the piston cylinder 2, and polishing liquid is poured into the cavity between the inner side of the piston 4 and the inner surface of the piston cylinder 2; the outlet at the inner end of the piston cylinder 2 is connected to one end of the rotating member 5, and the other end of the rotating member 5 is connected to the connecting member 6, and the other end of the connecting member 6 clamps one end of the workpiece 7 through an internal buckle;

[0049] The magnetron fluid unit includes a magnet, a guide rail 9, a guide rail bracket 8, and a yoke 10. The guide rail bracket 8 is located below the workpiece 7 and is fixedly connected to the workpiece 7 platform. The guide rail 9 is mounted on the guide rail bracket 8, with the axial direction of the guide rail 9 parallel to the axial direction of the workpiece 7. The yoke 10 is slidably connected to the guide rail 9. The magnet is fixed to the yoke 10. The distance between the magnet and the workpiece 7 is 1-3 mm.

[0050] The rotating member 5 includes a fixed section and a rotating section, which are connected via an internal bearing. The fixed section is connected to the piston cylinder 2 , and the moving section is connected to the workpiece 7 via a connecting member 6 .

[0051] Furthermore, there are three guide rails 9 , which are installed at equal intervals in a plane parallel to the working platform 13 .

[0052] Furthermore, there are two magnets, which have the same structure and are symmetrically mounted on the yoke 10 on the front and rear sides of the workpiece 7. Each magnet includes a pole 11 and a pole tip 12. The two magnets and the yoke 10 form an isosceles triangle structure with an upper opening, and the distance between the pole tip 12 and the workpiece 7 is 1-3 mm.

[0053] Furthermore, the rotation speed of the workpiece 7 is 6-20 revolutions per minute.

[0054] Furthermore, the magnet moves along the guide rail 9 to perform magnetic control flow field polishing on each point on the inner surface of the workpiece 7 in the axial direction.

[0055] Furthermore, the polishing medium in the polishing liquid is selected according to the workpiece material: cerium oxide is selected when the workpiece material is quartz glass, aluminum oxide is selected when the workpiece material is stainless steel, and diamond powder is selected when the workpiece material is cast iron.

[0056] A method for fluid polishing the inner surface of an elongated tube, comprising the following steps:

[0057] Step 1: Select a suitable polishing medium according to the material of the workpiece 7 to prepare a polishing liquid, stir the prepared polishing liquid evenly and then absorb it into the inner cavity of the piston cylinder 2.

[0058] Step 2: Connect the outlet of the piston cylinder 2 to the rotating part 5 and the connecting part 6 through a threaded connection. The connecting part 6 is connected to the two ends of the workpiece 7 through its internal buckle. After the whole connection is completed, check the sealing.

[0059] Step 3: Place the magnet on the yoke 10 so that the distance between the magnetic pole tip 12 and the outer wall of the workpiece 7 is 1-3 mm.

[0060] Step 4: Rotate the rotating member 5 through an external transmission device to control the speed of the workpiece 7 to be 6-20 revolutions per minute.

[0061] Step 5: Use an external push rod to push the piston rods 1 at both ends to move synchronously, ensuring that the polishing liquid is pushed out by the piston cylinder 2 on one side while the polishing liquid is sucked into the piston cylinder 2 on the other side. The polishing liquid flushes back and forth on the inner surface of the workpiece 7 under the pushing action of the piston rod 1, thereby polishing the inner surface of the workpiece 7.

[0062] Step 6: Move the magnet along the guide rail 9 to attract magnetic powder in different areas of the workpiece 7 to adhere to the pipe wall to produce a blocking effect.

[0063] Step 7: After the processing is completed, the rotation is stopped, the workpiece 7 is removed, and placed in an ultrasonic cleaning machine for cleaning.

[0064] Step 8: The workpiece 7 is inspected after processing, and its inner surface quality reaches the expected target, and the polishing process is completed.

[0065] The working principle of the present invention is as follows:

[0066] Two fluid processing units clamp the two ends of the workpiece 7. At the same time, the fluid processing units contain polishing liquid. The polishing liquid flows through the workpiece 7 at a certain speed under a certain pressure. The abrasive particles in the polishing liquid scratch, plow and wear the inner surface material of the workpiece 7, thereby polishing the inner surface of the workpiece 7.

[0067] The magnetron fluid unit is located on one side of the workpiece 7. The magnetic field applied by the magnetic pole 11 controls the magnetic particles in the polishing liquid to form a magnetic chain with a certain yield strength along the direction of the magnetic force, forming a blocking block close to the inner surface of the workpiece 7, changing the actual flow diameter of the polishing liquid in this area, greatly increasing the circulation speed of the polishing liquid at this location, and thereby improving the material removal efficiency in this area.

[0068] The piston cylinder 2 is fixedly connected to the work platform 13 through the piston cylinder bracket 3, which is used to determine the position of the piston cylinder 2 and provide support; the workpiece 7 is located between the two piston cylinders 2, ensuring that the polishing liquid in the inner cavity of the piston cylinder 2 can pass through the inner surface of the workpiece 7 in a straight-through manner during operation; the piston 4 is in contact with the inner surface of the piston cylinder 2, and the piston 4 can move flexibly in the piston cylinder 2. At the same time, the piston 4 is sealed from the inner surface of the piston cylinder 2 to ensure that the polishing liquid can be pressurized under the action of the piston 4; the outlet of the piston cylinder 2 is connected to the rotating part 5 to ensure that the piston cylinder 2 remains fixed when the workpiece 7 rotates, which is convenient for the operation of the piston 4; the other end of the rotating part 5 is connected to the connecting part 6, and the other end of the connecting part 6 clamps the workpiece 7; the two ends of the workpiece 7 are respectively connected to a connecting part 6 to ensure the sealing of the entire device and to clamp the workpiece 7 to determine its position.

[0069] The guide rail 9 is suspended below the workpiece 7 by the guide rail bracket 8. The axial direction of the guide rail 9 is parallel to the axial direction of the workpiece 7 and is used to determine the movement direction and movement range of the magnet; the yoke 10 contacts the guide rail 9 through the hole groove below and can move linearly on the guide rail 9; the magnet is fixed on the yoke 10 to ensure that it can move linearly below the workpiece 7, thereby controlling the magnetic field range; the magnet needs to be as close to the workpiece 7 as possible to ensure that the polishing liquid in the workpiece 7 can be subjected to a sufficiently large magnetic field force.

[0070] The rotation of the workpiece 7 is achieved by rotating the rotating member 5. The rotating member 5 is divided into two parts, connected by a bearing in the middle, so that one part can rotate while the other part is fixed. One end of the rotating member 5 is connected to the piston cylinder 2 to maintain its immobility, and the other end is connected to the workpiece 7 through the connecting member 6, ensuring that the workpiece 7 and the rotating member 5 can rotate together.

[0071] The magnet can move at a constant speed along the guide rail 9, and the controllability and uniformity of the polishing of the entire inner surface of the workpiece 7 are ensured by performing magnetic control flow field polishing on each point in the axial direction of the inner surface of the workpiece 7.

[0072] An embodiment of the present invention is as follows:

[0073] A method for polishing the inner surface of a slender tube comprises the following steps:

[0074] Step 1: Install and connect the polishing device according to the process sequence and check the air tightness of the device.

[0075] Step 2: Workpiece 7 is made of stainless steel with an inner diameter of 0.3 mm and an outer diameter of 0.6 mm. The original inner surface roughness is 650 μm. Aluminum oxide is selected as the polishing medium, and 200 mL of polishing liquid is prepared with water at a mass ratio of 3:7. The prepared polishing liquid is stirred with a magnetic stirrer for 10 minutes. The stirred polishing liquid is then drawn into the inner cavity of the piston cylinder 2 in the two fluid processing units.

[0076] Step 3: The workpiece 7 is clamped and fixed between the two fluid processing units. Both ends of the workpiece 7 are connected to the inner cavity of the piston cylinder 2 through the connecting piece 6 and the rotating piece 5, so that the polishing liquid can flow into the interior of the workpiece 7 for processing.

[0077] Step 4: Push and pull the piston rods 1 on the left and right sides in turn to allow the polishing liquid to move quickly in the inner cavity of the left and right piston cylinders 2 and the workpiece 7, so that the polishing liquid flow rate reaches 35 mL / s, and flush continuously 1000 times; at the same time, rotate the rotating part 5 so that the workpiece 7 rotates slowly at a speed of 10 revolutions per minute.

[0078] Step 5: After the processing is completed, stop pushing the piston rod 1, remove the stainless steel workpiece 7, put it into an ultrasonic cleaning machine for cleaning, and use an air gun to dry its inner surface to remove the residual polishing liquid.

[0079] Step 6: Bevel cut the workpiece 7 after processing, and inspect the surface quality of the inner surface of the cross section. The overall roughness Ra is about 46nm, and the optimal local roughness reaches Ra 32nm.

[0080] The front, back, left, and right of the present invention are only relative to FIG1 and do not constitute any limitation to the present invention.

[0081] The above is only a preferred embodiment of the present invention. It should be pointed out that due to the limitations of textual expression, there are objectively infinite specific structures. For ordinary technicians in this technical field, without departing from the principles of the present invention, they can make several improvements, modifications or changes, and can also combine the above technical features in an appropriate manner; these improvements, modifications, changes or combinations, or the direct application of the concepts and technical solutions of the application to other occasions without improvement, should be regarded as the scope of protection of the present invention.

Claims

1. A fluid polishing device for the inner surface of an elongated tube, characterized in that: It comprises a working platform (13), a fluid processing unit and a magneto-fluid unit; there are two fluid processing units, which are symmetrically installed on the left and right sides of the working platform (13); the left and right ends of the slender tube, i.e. the workpiece (7), are respectively connected to the fluid processing units on the left and right sides; The magnetic control fluid unit is located at the lower side of the workpiece (7), and the magnetic field applied by the magnetic pole (11) controls the magnetic particles in the polishing liquid in the fluid processing unit to form a magnetic chain with a certain yield strength along the magnetic force direction, which is adsorbed on the inner surface of the workpiece (7) to form a local blocking block, thereby reducing the actual flow diameter of the polishing liquid in the blocking area; The fluid processing unit comprises a piston (4), a piston cylinder (2), a piston rod (1), a rotating part (5), a connecting part (6) and a piston cylinder bracket (3); the piston cylinder (2) is fixedly connected to the working platform (13) via the piston cylinder bracket (3); the inner end of the piston rod (1) is fixedly connected to the piston (4), and the piston rod (1) is slidably connected to the opening at the outer end of the piston cylinder (2); the piston (4) is slidably connected to the inner surface of the piston cylinder (2), and polishing liquid is poured into the cavity between the inner side of the piston (4) and the inner surface of the piston cylinder (2); the outlet at the inner end of the piston cylinder (2) is connected to one end of the rotating part (5), the other end of the rotating part (5) is connected to the connecting part (6), and the other end of the connecting part (6) clamps one end of the workpiece (7) through an internal buckle; The magnetron fluid unit comprises a magnet, a guide rail (9), a guide rail bracket (8) and a yoke (10); the guide rail bracket (8) is located below the workpiece (7) and is fixedly connected to the workpiece (7) platform; the guide rail (9) is mounted on the guide rail bracket (8), and the axial direction of the guide rail (9) is parallel to the axial direction of the workpiece (7); the yoke (10) is slidably connected to the guide rail (9); the magnet is fixed on the yoke (10); the distance between the magnet and the workpiece (7) is 1-3 mm; The rotating part (5) comprises a fixed section and a rotating section, wherein the fixed section and the rotating section are connected via an internal bearing, the fixed section is connected to the piston cylinder (2), and the movable section is connected to the workpiece (7) via a connecting part (6).

2. A fluid polishing device for the inner surface of an elongated tube according to claim 1, characterized in that: There are three guide rails (9) which are installed at equal intervals in a plane parallel to the working platform (13).

3. The fluid polishing device for the inner surface of an elongated tube according to claim 1, characterized in that: There are two magnets, which have the same structure and are symmetrically mounted on the yokes (10) on the front and rear sides of the workpiece (7). Each magnet comprises a magnetic pole (11) and a magnetic pole tip (12). The two magnets and the magnetic yoke (10) form an isosceles triangle structure with an upper opening, and the distance between the magnetic pole tip (12) and the workpiece (7) is 1-3 mm.

4. The fluid polishing device for the inner surface of an elongated tube according to claim 1, characterized in that: The rotation speed of the workpiece (7) is 6-20 revolutions per minute.

5. The fluid polishing device for the inner surface of an elongated tube according to claim 1, characterized in that: The magnet moves along the guide rail (9) to perform magnetic control flow field polishing on each point on the inner surface of the workpiece (7) in the axial direction.

6. The fluid polishing device for the inner surface of an elongated tube according to claim 1, characterized in that: The polishing medium in the polishing liquid is selected according to the workpiece material: cerium oxide is selected when the workpiece material is quartz glass, aluminum oxide is selected when the workpiece material is stainless steel, and diamond powder is selected when the workpiece material is cast iron.

7. A method for polishing the inner surface of an elongated tube by fluid, using the elongated tube inner surface fluid polishing device as claimed in claim 1, characterized in that: The steps include: Step 1: Select a suitable polishing medium according to the material of the workpiece (7) to prepare a polishing liquid, stir the prepared polishing liquid evenly and then suck it into the inner cavity of the piston cylinder (2); Step 2: Connect the outlet of the piston cylinder (2) to the rotating member (5) and the connecting member (6) through threaded connection. The connecting member (6) is connected to the two ends of the workpiece (7) through its internal buckle. After the whole is connected, check the sealing performance; Step 3: Place the magnet on the yoke (10) so that the distance between the magnetic pole tip (12) and the outer wall of the workpiece (7) is 1-3 mm; Step 4: Rotate the rotating member (5) through an external transmission device to control the speed of the workpiece (7) to be 6-20 revolutions per minute; Step 5: Use an external push rod to push the piston rods (1) at both ends to move synchronously, so that the polishing liquid is pushed out by the piston cylinder (2) on one side while the polishing liquid is sucked into the piston cylinder (2) on the other side. The polishing liquid flushes back and forth on the inner surface of the workpiece (7) under the pushing action of the piston rod (1), thereby polishing the inner surface of the workpiece (7). Light processing; Step 6: Move the magnet along the guide rail (9) to absorb magnetic powder in different areas of the workpiece (7) to adhere to the pipe wall to produce a blocking effect; Step 7: After the processing is completed, the rotation is stopped, the workpiece (7) is removed, and placed in an ultrasonic cleaning machine for cleaning; Step 8: The processed workpiece (7) is inspected, and its inner surface quality reaches the expected target, and the polishing process is completed.

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