A turbulence-assisted dynamic magnetic field magnetorheological polishing device and method

Abstract

This invention relates to a turbulence-assisted dynamic magnetic field magnetorheological polishing device and method, belonging to the field of precision and ultra-precision machining technology. The device includes a base plate, a reciprocating moving mechanism, a rotary drive system, a magnetic field adjustment system, a turbulence generating component, a fluid circulation system, and a pipe fixing component. The turbulence generating component is a spiral head fitted onto a cylindrical magnet. The reciprocating moving mechanism drives the cylindrical magnet in reciprocating linear motion, and the rotary drive system drives the cylindrical magnet to rotate, forming a dynamic magnetic field. When the spiral head rotates, it generates uniform turbulence within the flow channel of the pipe wall, simultaneously creating a localized necking inside the pipe, increasing the flow velocity and pressure of the magnetorheological fluid, and enhancing the impact energy of the abrasive particles on the wall surface. The fluid circulation system achieves closed-loop circulation and maintains the activity of the magnetorheological fluid. This invention achieves uniform distribution of the magnetorheological fluid through turbulence generated by the rotation of the spiral head, and forms a dynamic magnetic field through the combined reciprocating and rotary motion of the cylindrical magnet. The magnetic field parameters can be adjusted in real time according to the polishing process, effectively improving the efficiency and uniformity of polishing the inner wall of pipes. It is suitable for ultra-smooth polishing of the inner walls of various slender pipes and precision fluid pipes.

Description

[0001] This invention relates to a turbulence-assisted dynamic magnetic field magnetorheological polishing device and method, belonging to the field of precision and ultra-precision machining technology. Background Technology

[0002] In modern manufacturing, fields such as aerospace, hydraulic transmission, and precision chemicals place extremely high demands on the surface quality of the inner wall of small-diameter, slender pipes. Defects such as burrs, microcracks, and machining textures on the inner wall of pipe fittings directly affect fluid transport efficiency, sealing performance, and equipment service life. Therefore, it is necessary to achieve smooth inner wall finishing through a special polishing process.

[0003] Traditional pipe inner wall polishing technology has many limitations: mechanical polishing uses rigid grinding heads, which are limited by the slender structure of pipes and cannot achieve full-area processing. The polishing uniformity is poor, and the equipment precision requirements are extremely high. It is necessary to ensure the coaxiality of the grinding head and the pipe, otherwise it is easy to cause eccentric wear or damage to the pipe wall. At the same time, high-precision processing equipment is expensive. The abrasive distribution of abrasive flow polishing is random, and the processing effect is greatly affected by process parameters, which can easily lead to uneven processing allowance. Although chemical polishing can handle complex pipes, the polishing waste liquid pollutes the environment and does not meet the requirements of green manufacturing.

[0004] When existing magnetorheological polishing devices are applied to the inner walls of pipes, the magnetic field generator is typically fixed to the outside of the pipe or inside the polishing tool. The magnetic field distribution is statically fixed and cannot be dynamically adjusted according to the polishing process. Furthermore, polishing tools are often smooth shafts, which can cause laminar flow of the magnetorheological fluid within the polishing gaps, leading to abrasive particle sedimentation and affecting polishing uniformity. These technical shortcomings result in low polishing efficiency, poor consistency in the inner wall surface finish, and insufficient measures to maintain the activity of the magnetorheological fluid, further hindering the widespread application of magnetorheological polishing technology in the processing of slender pipe inner walls.

[0005] To overcome the above problems, this invention discloses a turbulence-assisted dynamic magnetic field magnetorheological polishing device and method. Turbulence is generated by the rotation of the spiral head to achieve uniform distribution of the magnetorheological fluid. A dynamic magnetic field is formed by the reciprocating motion of the array of magnets, which enables real-time adjustment of the magnetic field strength and distribution during the polishing process, thereby improving the efficiency and uniformity of polishing the inner wall of the pipe. Summary of the Invention

[0006] A turbulence-assisted dynamic magnetic field magnetorheological polishing device includes a base plate, a reciprocating moving mechanism, a rotary drive system, a magnetic field adjustment system, a turbulence generating component, a fluid circulation system, and a pipe fixing component. The reciprocating moving mechanism provides reciprocating power to the magnetic field adjustment system; the rotary drive system provides rotational power to the magnetic field adjustment system; the magnetic field adjustment system can perform reciprocating linear motion and rotational motion inside the turbulence generating component to form a dynamic magnetic field to adapt to the magnetic field requirements of different polishing stages; the turbulence generating component generates turbulence in the flow channel on the inner wall of the pipe during rotation to prevent the magnetorheological fluid from settling; the fluid circulation system realizes the circulation and delivery of the magnetorheological fluid and maintains its activity; the pipe fixing component is used for coaxial fixation of the pipe to be polished, and all components are integrated and installed on the base plate.

[0007] The reciprocating motion mechanism includes a speed-regulating motor 1, a motor baffle 2, a lead screw side plate 17, a lead screw 16, a slider 15, and a lead screw base 14. The speed-regulating motor 1 is bolted to the motor baffle 2. One end of the lead screw 16 is connected to the output shaft of the speed-regulating motor 1, and the other end is supported and fixed by the lead screw side plate 17. The slider 15 is threadedly engaged with the lead screw 16 and is fixed on the lead screw base 14. Driven by the speed-regulating motor 1, the lead screw 16 drives the slider 15 to perform linear reciprocating motion along the axial direction.

[0008] The rotary drive system includes a stepper motor 3 and a coupling 4. The stepper motor 3 is fixed on the slider 15 and reciprocates with the slider 15. One end of the coupling 4 is connected to the output shaft of the speed-regulating motor 3, and the other end is fixedly connected to the cylindrical magnet 5. The stepper motor 3 can drive the cylindrical magnet 5 to rotate.

[0009] The turbulence generating component is a spiral head 23, which is sleeved on a cylindrical magnet 5. The cylindrical magnet 5 passes through the left end of the T-shaped connector 6 and extends into the workpiece 7. Driven by the stepper motor 3, it can perform reciprocating linear motion and rotational motion inside the workpiece 7 to form a dynamic magnetic field. The axial movement range of the cylindrical magnet 5 partially overlaps with the axial length of the workpiece 7.

[0010] The pipe fixing assembly includes a workpiece clamp 24, a support frame 18, and a support frame pad 19. The workpiece 7 is fixed to the base plate 10 by the workpiece clamp 24 and the support frame 18. The support frame 18 supports the workpiece clamp 24 by bolts, is fixed to the support frame pad 19, and then fixed to the base plate 10. The left end of the workpiece 7 is connected to the right end of the T-shaped connector 6. The left end of the T-shaped connector 6 allows the cylindrical magnet 5 to pass through, and the lower end of the T-shaped connector 6 is connected to the inlet pipe 12. The right end of the workpiece 7 is connected to the left end of the second T-shaped connector 6. The right end of the second T-shaped connector 6 is sealed with a lip seal ring 21, and the lower end is connected to the outlet pipe 8. The workpiece 7 and the T-shaped connector 6 are sealed by an O-ring seal ring 22.

[0011] The magnetic field adjustment system includes a cylindrical magnet 5, which passes through the left end of the T-shaped connector 6 and extends into the workpiece 7. Driven by the speed-regulating motor 3, the cylindrical magnet 5 can perform reciprocating linear and rotational motions inside the workpiece 7 to form a dynamic magnetic field. The axial movement range of the cylindrical magnet 5 partially overlaps with the axial length of the workpiece 7.

[0012] The fluid circulation system includes a storage tank 11, a piston pump 13, a delivery pipe 20, an inlet pipe 12, an outlet pipe 8, and a stirring motor 9. The storage tank 11 is a storage container for the magnetorheological fluid. The stirring head of the stirring motor 9 extends into the storage tank 11 and can rotate and stir the magnetorheological fluid to maintain the uniform suspension and good activity of the abrasive particles in the magnetorheological fluid. The inlet end of the piston pump 13 is connected to the storage tank 11 through the delivery pipe 20, and the outlet end is connected to the inlet pipe 12. The inlet pipe 12 is connected to the T-connector 6. The lower end of the T-connector 6 on the right side of the workpiece 7 is connected to the outlet pipe 8, and the end of the outlet pipe 8 is connected to the storage tank 11.

[0013] The aforementioned turbulence-assisted dynamic magnetic field magnetorheological polishing device has a base plate 10 that is a T-shaped groove plate, and the axial spacing of each component can be adjusted for easy installation and adjustment.

[0014] In the aforementioned turbulence-assisted dynamic magnetic field magnetorheological polishing device, the speed-regulating motor 3 in the rotary drive system has an output speed range of 0-3000 r / min.

[0015] In the aforementioned turbulence-assisted dynamic magnetic field magnetorheological polishing device, the annular polishing gap between the spiral head 23 and the inner wall of the workpiece 7 is 0.5-2mm.

[0016] In the aforementioned turbulence-assisted dynamic magnetic field magnetorheological polishing device, the cylindrical magnet 5 performs reciprocating linear and rotational motions inside the workpiece 7, forming a dynamic magnetic field of 0.3-1.2T within the polishing gap.

[0017] In the aforementioned turbulence-assisted dynamic magnetic field magnetorheological polishing device, the reciprocating speed of the slider 15 in the reciprocating moving mechanism is 1-4 mm / s.

[0018] In the aforementioned turbulence-assisted dynamic magnetic field magnetorheological polishing device, the stirring motor 9 in the fluid circulation system has a stirring speed of 100-300 r / min, and the piston pump 13 has a delivery flow rate of 3-10 L / min.

[0019] A magnetorheological polishing method for the inner wall of a pipe using the aforementioned device includes the following steps:

[0020] Step 1, Fitting clamping and coaxial adjustment: Fix the workpiece 7 to be polished coaxially on the base plate 10 through the workpiece clamp 24 and the support frame 18. Connect both ends of the workpiece 7 to the T-shaped connector 6. Seal the connection with the O-ring 22. Let the cylindrical magnet 5 with the spiral head 23 pass through the T-shaped connector 6 and extend into the workpiece 7. Adjust the coaxiality of the cylindrical magnet 5 and the workpiece 7 to ensure that there is a 0.5-2mm annular polishing gap between the spiral head 23 and the workpiece 7.

[0021] Step 2, magnetorheological fluid activity pretreatment: Add the prepared magnetorheological fluid to the storage tank 11, start the stirring motor 9, and continuously stir the magnetorheological fluid by rotating the stirring head;

[0022] Step 3, Initial adjustment of magnetic field: Start stepper motor 1, drive slider 15 to move through lead screw 16, and then drive speed control motor 3, coupling 4 and cylindrical magnet 5 to move to the set position, forming an initial magnetic field of 0.3-1.2T in the polishing gap;

[0023] Step 4, Magnetorheological fluid circulation and transportation: Start the piston pump 13. The piston pump 13 draws magnetorheological fluid from the storage tank 11 through the liquid delivery pipe 20, and delivers it to the polishing gap inside the workpiece 7 through the liquid inlet pipe 12 and T-joint 6. Under the action of the magnetic field generated by the cylindrical magnet 5, the magnetorheological fluid flows into a flexible polishing mold with viscoplasticity. The magnetorheological fluid flowing through the polishing gap flows back to the storage tank 11 through the T-joint 6 and the liquid outlet pipe 8 at the other end.

[0024] Step 5, Turbulence Generation and Dynamic Magnetic Field Polishing: Start the speed-regulating motor 3, which drives the cylindrical magnet 5 to rotate at high speed through the coupling 4. The spiral head 23, which is sleeved on the cylindrical magnet 5, rotates accordingly, generating turbulence in the flow channel of the inner wall of the workpiece 7, forming uniform turbulence. At the same time, the spiral head 23 forms a local necking inside the workpiece 7, which increases the flow velocity and pressure of the magnetorheological fluid when passing through the necking area. Simultaneously, control the forward and reverse rotation of the stepper motor 3, which drives the lead screw 16 to rotate reciprocally, causing the slider 15 to perform reciprocating linear motion. This, in turn, drives the speed-regulating motor 3 and the cylindrical magnet 5 to perform continuous reciprocating linear motion inside the workpiece 7. Control the speed-regulating motor 3 to drive the cylindrical magnet 5 to rotate, forming a dynamic magnetic field, and dynamically adjusting the magnetic field strength and distribution in the polishing gap. Under the action of turbulence, dynamic magnetic field, and relative shearing action between the flexible polishing mold and the inner wall of the workpiece 7, the material on the inner wall of the workpiece 7 is removed.

[0025] Step 6, Polishing stage switching and parameter adjustment: According to the polishing process, the rough polishing and fine polishing stages are switched in sequence. The turbulence intensity is changed by adjusting the speed of the speed-regulating motor 3, the reciprocating speed of the cylindrical magnet 5 is changed by adjusting the speed of the stepper motor 1, and the delivery rate of the magnetorheological fluid is changed by adjusting the flow rate of the piston pump 13, so as to adapt to the process parameter requirements of different polishing stages.

[0026] Step 7, Polishing Finishing: After the inner wall of workpiece 7 has been polished to the preset requirements, turn off the speed regulating motor 3, stepper motor 1 and piston pump 13 in sequence; after all the magnetorheological fluid in the polishing gap has flowed back to the storage tank 11, disconnect the workpiece 7 from the T-joint 6 and remove the polished workpiece 7 from the workpiece fixture 24.

[0027] Compared to existing technologies, the advantages of this invention are as follows: This invention employs a circulating spiral rod structure. The spiral rod extends into the interior of the pipe, forming a localized necking in the flow channel. This causes the magnetorheological fluid to flow faster and increase in pressure as it passes through the necking region, effectively enhancing the impact energy of the abrasive particles on the pipe wall. Simultaneously, the spiral rod generates turbulence during rotation, disrupting the laminar flow state and enhancing the flow performance of the magnetorheological fluid, preventing abrasive sedimentation. Furthermore, a dynamic magnetic field is generated by the reciprocating and rotating motion of the cylindrical magnet 5, compensating for the insufficient attenuation of the magnetic field with distance. This allows for real-time adjustment of the magnetic field strength and distribution during polishing, thereby improving the efficiency and uniformity of polishing the inner wall of the pipe. Attached Figure Description

[0028] Figure 1 This is a front view of a turbulence-assisted dynamic magnetic field magnetorheological polishing device and method according to the present invention.

[0029] Figure 2 A three-dimensional image of a magnetorheological polishing device for the inner wall of a pipe, used for turbulence generation and magnetic field regulation.

[0030] Figure 3 An axial cross-sectional view of the fit between the spiral head and the pipe fitting.

[0031] The labels in the diagram are as follows: 1-Stepper motor, 2-Motor baffle, 3-Speed-regulating motor, 4-Coupling, 5-Cylindrical magnet, 6-T-joint, 7-Workpiece, 8-Outlet pipe, 9-Electric stirrer, 10-Base plate, 11-Storage tank, 12-Inlet pipe, 13-Piston pump, 14-Lead screw base, 15-Lead screw slider, 16-Lead screw, 17-Lead screw side plate, 18-Support frame, 19-Padded block, 20-Delivery pipe, 21-Lip seal, 22-O-ring, 23-Screw head, 24-Workpiece clamp Detailed Implementation

[0032] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0033] Example: Figure 1-3 This invention relates to a turbulence-assisted dynamic magnetic field magnetorheological polishing device and method.

[0034] The specific steps for using this invention are as follows:

[0035] 1. Install the base plate 10 on the ground. The upper part of the base plate 10 is a T-shaped groove plate that is easy to install and adjust.

[0036] 2. Assemble the reciprocating movement mechanism: Connect the stepper motor 3 to the motor baffle 2 with bolts. Connect one end of the lead screw 16 to the output shaft of the stepper motor 3, and support and fix the other end through the lead screw fixing block 17. The slider 15 is threadedly engaged with the lead screw 16 and is fixed on the lead screw base 14.

[0037] 3. Assemble the rotary drive system and magnetic field adjustment system: Fix the speed-regulating motor 1 on the slider 15 and make reciprocating motion with the slider 15; connect one end of the coupling 4 to the output shaft of the speed-regulating motor 1 and the other end to the cylindrical magnet 5; put the helical head 23 on the cylindrical magnet 5.

[0038] 4. Assemble the pipe fitting fixing assembly and turbulence generating assembly: Fix the workpiece 7 to the base plate 10 using the workpiece clamp 24 and the support frame 18; the support frame 18 is bolted to support the workpiece clamp 24, fixed to the support frame pad 19, and then fixed to the base plate 10; the left end of the workpiece 7 is connected to the right end of the T-shaped connector 6, the left end of the T-shaped connector 6 allows the cylindrical magnet 5 to pass through, and the lower end of the T-shaped connector 6 is connected to the liquid inlet pipe 12; the right end of the workpiece 7 is connected to the left end of the second T-shaped connector 6, the right end of the second T-shaped connector 6 is sealed with a lip seal ring 21, and the lower end is connected to the liquid outlet pipe 8; the workpiece 7 and the T-shaped connector 6 are sealed with an O-ring seal ring 22; the cylindrical magnet 5 with a spiral head 23 is inserted into the workpiece 7 through the T-shaped connector 6, and a 1.0mm annular polishing gap is left between the spiral head 23 and the workpiece 7.

[0039] 5. Assemble the fluid circulation system: Place the storage tank 11 on the base plate 10, and extend the stirring head of the stirring motor 9 into the storage tank 11; the inlet end of the piston pump 13 is connected to the storage tank 11 through the liquid delivery pipe 20, and the outlet end is connected to the inlet pipe 12; the lower end of the T-shaped connector 6 on the right end of the workpiece 7 is connected to the outlet pipe 8, and the end of the outlet pipe 8 is connected to the storage tank 11.

[0040] 6. Adjust the coaxiality of each component: Adjust the axial distance and radial position of each module to make the center axis of the speed regulating motor 1, the cylindrical magnet 5, the workpiece 7 and the load end coincide.

[0041] During the experiment, the stirring motor 9 was first started and the stirring speed was adjusted to 200 r / min to continuously agitate the magnetorheological fluid. The stepper motor 3 was started, which moved the slider 15 through the lead screw 16, thereby moving the speed-regulating motor 1 and the cylindrical magnet 5 to the set position, forming an initial magnetic field of 0.8T in the polishing gap. The piston pump 13 was started and the delivery flow rate was adjusted to 6 L / min to deliver the magnetorheological fluid to the polishing gap inside the workpiece 7. The speed-regulating motor 1 was started and the speed was adjusted to 1500 r / min, which drove the cylindrical magnet 5 to rotate at high speed through the coupling 4. The spiral head 23 sleeved on the cylindrical magnet 5 rotated accordingly, generating uniform turbulence in the flow channel inside the inner wall of the workpiece 7. Meanwhile, the spiral head 23 forms a localized necking inside the workpiece 7, causing the magnetorheological fluid to flow faster and increase pressure when passing through the necking area. At the same time, the stepper motor 3 is controlled to rotate in both directions, the reciprocating speed of the slider 15 is adjusted to 2 mm / s, and the speed-regulating motor 1 is controlled to drive the cylindrical magnet 5 to rotate, so that the cylindrical magnet 5 performs a continuous reciprocating and rotating compound motion inside the workpiece 7, forming a dynamic magnetic field of 0.3-0.8T in the polishing gap. Under the uniform turbulence, the dynamic magnetic field, and the relative shearing action between the flexible polishing mold and the inner wall of the workpiece 7, the material on the inner wall of the workpiece 7 is removed. After polishing is completed, the speed-regulating motor 1, the stepper motor 3, and the piston pump 13 are turned off in sequence, the workpiece 7 is removed, and the polishing operation is completed.

[0042] The specific embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A turbulence-assisted dynamic magnetic field magnetorheological polishing device and method, characterized in that: The system includes a base plate, a reciprocating moving mechanism, a rotary drive system, a magnetic field adjustment system, a turbulence generating component, a fluid circulation system, and a pipe fixing component. The reciprocating moving mechanism includes a stepper motor, a motor baffle, a lead screw fixing block, a lead screw, a slider, and a lead screw base plate. The rotary drive system includes a speed-regulating motor and a coupling. The magnetic field adjustment system includes a cylindrical magnet. The turbulence generating component is a helical head fitted onto the cylindrical magnet. The fluid circulation system includes a storage tank, a pump, a delivery pipe, an inlet pipe, an outlet pipe, and a stirring motor. The pipe fixing component includes a clamp, a support frame, and a support. A support block is provided; the stepper motor drives the slider to perform linear reciprocating motion via a lead screw, and the speed-regulating motor is fixed on the slider and moves reciprocally with the slider. The speed-regulating motor is connected to the cylindrical magnet via a coupling and drives the cylindrical magnet to rotate. The cylindrical magnet passes through the T-joint and extends into the workpiece. The spiral head moves reciprocating linearly and rotatingly with the cylindrical magnet inside the workpiece, generating turbulence and forming local necking in the flow channel on the inner wall of the workpiece. The pump draws magnetorheological fluid from the storage tank through the liquid delivery pipe, and delivers it to the polishing gap between the inner wall of the workpiece and the spiral head through the liquid inlet pipe and the T-joint. The magnetorheological fluid flows back to the storage tank through the liquid outlet pipe.

2. The turbulence-assisted dynamic magnetic field magnetorheological polishing device and method according to claim 1, characterized in that: The speed-regulating motor outputs a speed range of 0-3000 r / min; the pipe inner wall magnetorheological polishing device based on turbulence generation and magnetic field adjustment is characterized in that: the annular polishing gap between the spiral head and the inner wall of the workpiece is 0.5-2 mm; the pipe inner wall magnetorheological polishing device based on turbulence generation and magnetic field adjustment is characterized in that: the cylindrical magnet performs reciprocating linear motion and rotational motion inside the workpiece, forming a dynamic magnetic field of 0.3-1.2 T within the polishing gap.

3. The turbulence-assisted dynamic magnetic field magnetorheological polishing device and method according to claim 1, characterized in that: The support frame is bolted to support the workpiece clamp, fixed on the support frame pad, and then fixed on the base plate.

4. The turbulence-assisted dynamic magnetic field magnetorheological polishing device and method according to claim 1, characterized in that: The ball screw and the screw slider in the reciprocating moving mechanism are threadedly engaged, the speed-regulating motor and the cylindrical magnet are connected by a coupling, the reciprocating moving speed of the screw slider is 1-4 mm / s, the stirring speed is 100-300 r / min, and the pump delivery flow rate is 3-10 L / min.

5. The turbulence-assisted dynamic magnetic field magnetorheological polishing device and method according to claim 1, characterized in that: One end of the tee connector is threaded through the drive shaft and has a rotary sealing device inside; the other end is connected to the end of the pipe fitting, and an O-ring is provided at the connection position.

6. A method for magnetorheological polishing of the inner wall of a pipe using the apparatus described in any one of claims 1-5, characterized in that, Includes the following steps: (1) Fix the workpiece to be polished on the base plate coaxially using a fixture and a support frame. Connect both ends of the workpiece to the T-shaped connector so that the cylindrical magnet with the spiral head passes through the T-shaped connector and extends into the workpiece. Adjust the coaxiality between the cylindrical magnet and the workpiece to ensure that there is an annular polishing gap between the spiral head and the workpiece. (2) Start the fluid circulation system to deliver magnetorheological fluid to the polishing gap; (3) Start the stepper motor, drive the slider to move through the lead screw, and then drive the speed-regulating motor and the cylindrical magnet to move to the set position to form an initial magnetic field in the polishing gap; (4) Start the pump to deliver the magnetorheological fluid to the polishing gap inside the workpiece. Under the action of the magnetic field generated by the cylindrical magnet, the magnetorheological fluid flows into a flexible polishing mold and flows back to the storage tank after passing through the polishing gap. (5) Start the speed-regulating motor to drive the cylindrical magnet to rotate at high speed. The spiral head fitted on the cylindrical magnet rotates accordingly, generating turbulence in the flow channel inside the workpiece. At the same time, the spiral head forms a local necking inside the workpiece. Control the stepper motor to rotate forward and backward, so that the cylindrical magnet makes continuous reciprocating linear motion inside the workpiece. Control the speed-regulating motor to drive the cylindrical magnet to rotate, forming a dynamic magnetic field. Under the action of turbulence, dynamic magnetic field and relative shearing action between the flexible polishing mold and the inner wall of the workpiece, the material inside the workpiece is removed.

7. The magnetorheological polishing method for the inner wall of a pipe according to claim 6, characterized in that: It also includes adjusting the rotation speed of the spiral head, the reciprocating speed of the array magnets, and the delivery flow rate of the magnetorheological fluid during the polishing process, depending on whether it is a rough polishing stage or a fine polishing stage.

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