A circular tube inner surface polishing device and method controlled by coupling of electromagnetic coil and permanent magnet

Abstract

The invention discloses a device and method for polishing the inner surface of a round tube controlled by coupling an electromagnetic coil and a permanent magnet, belonging to the field of inner surface polishing. The device comprises a workbench, a precision displacement platform, a magnetic field generating device, a hydraulic system device, an abrasive circulation device, a workpiece, and a fixture. The magnetic field gradient and magnetic field force of a polishing area are improved by coupling and controlling the electromagnetic coils and permanent magnets arranged in pairs and in parallel, thereby avoiding the problem of high heat generation when a single electromagnetic coil provides the required magnetic field strength. The direction and frequency of the alternating current passed into the paired electromagnetic coils are changed to realize controllable adjustment of the magnetic field force and magnetic field gradient of the polishing position. The paired electromagnetic coils dominate the magnetic field gradient of the processing area, and the combination of the permanent magnets increases the magnetic field strength of the processing area. At the same time, the angle between the paired electromagnetic coils is adjusted, and the arrangement of different magnetic poles is coordinated, so that polishing at any angle can be realized, thereby realizing efficient and high-quality targeted intelligent polishing of the workpiece.

Description

Technical Field

[0001] The invention relates to a round tube inner surface polishing technology, and in particular provides a round tube inner surface polishing device and method controlled by coupling of an electromagnetic coil and a permanent magnet. Background Art

[0002] In recent years, with the rapid development of machinery, petroleum, aerospace and other fields, higher requirements have been put forward for the polishing processing technology of various parts. Among them, there are many parts with hole surfaces in mechanical parts, and the inner hole surface processing accounts for about 1 / 3 of the total mechanical processing. The processing quality of the hole surface has an important impact on the performance and life of the parts and their products. Slender pipe fittings (inner diameter 2-6mm, aspect ratio greater than 25) are widely used in large machines such as aerospace, nuclear power plants, biomedicine, shipbuilding and military industries for the transportation or cooling of gases and liquids, such as artificial blood vessels, medical minimally invasive introduction devices, hydraulic catheters, high-throughput heat exchange tubes, refrigeration pipeline thin copper tubes, etc. Due to the characteristics of small diameter and large aspect ratio, the polishing conditions of the inner surface of slender tubes are more stringent. Exploring controllable and efficient polishing methods for the inner surface of slender tubes has become one of the hot spots in the development of precision machining technology, and has attracted great attention from scholars at home and abroad. Traditional polishing methods, such as honing and grinding, can only polish specific workpiece surfaces and complete a certain limit of processing, staying at the rough processing stage and cannot reach the micro-nano level; in addition, traditional polishing methods are time-consuming and labor-intensive, with poor economic efficiency and cannot accurately control cutting forces. Non-traditional polishing methods, such as abrasive flow polishing, magnetorheological polishing, magnetic grinding, etc., mostly use permanent magnets as magnetic field sources because permanent magnetic materials have advantages such as high hysteresis loops, high coercive force, high remanence, no need for external current to provide permanent magnetic fields, low manufacturing costs, and easy use. However, the magnetic induction intensity generated by permanent magnets is difficult to adjust, which leads to the uncontrollable size of the magnetic field and the inability to better control the pressure on the abrasive particles; at the same time, the polishing medium cannot achieve targeted control of the polishing medium by passing through the workpiece surface solely by magnetic force or flow pressure, but by adjusting the frequency and direction of the pulse current flowing through the electromagnetic coil, the magnetic field can be better controlled. The electromagnetic coil can generate magnetic field gradients and magnetic induction intensity at the processing position when an alternating current is passed through it, and the permanent magnet can increase the magnetic field force, greatly increasing the polishing effect, combining the advantages of the two. Therefore, in order to achieve the polishing of the inner surface of the slender tube, the present invention proposes a device and method for polishing the inner surface of a round tube based on the coupling control of an electromagnetic coil and a permanent magnet. Summary of the invention

[0003] The invention provides a circular tube inner surface polishing device and method controlled by electromagnetic coil and permanent magnet coupling. Through a magnetic field generating device composed of paired electromagnetic coils and permanent magnets, a magnetic polishing medium is used, a chuck drives a workpiece to rotate, and the coordinated movement of a comprehensive precision motion platform and an abrasive circulation system is performed to achieve efficient polishing of the circular tube inner surface. Paired electromagnetic coils are arranged in pairs and in parallel on a magnetic core. Compared with a single coil, the paired electromagnetic coils can generate a greater magnetic field intensity and a greater magnetic field gradient, thereby avoiding the problem of high heat generation when a single electromagnetic coil provides the required magnetic field intensity. The paired electromagnetic coils dominate the magnetic field gradient of the polishing area, and the composite of the permanent magnet increases the magnetic field intensity of the polishing area. The direction and frequency of the alternating current passed into the paired electromagnetic coils are changed, the magnetic field force and magnetic field gradient of the polishing position are adjusted in real time, and the shape of the magnetic polishing medium is regulated to achieve targeted control of complex curved surface polishing. In addition, by adjusting the angle change between the electromagnetic coils and the direction, size and frequency of the current, different magnetic pole arrangements are deployed to form magnetic lines of force of different loops, and polishing at any angle can be achieved, thereby achieving efficient and high-quality targeted intelligent polishing of the workpiece.

[0004] The present invention provides a circular tube inner surface polishing device controlled by coupling of an electromagnetic coil and a permanent magnet: the device comprises a workpiece support frame, a magnetic field generating device, a precision displacement platform, a workpiece, a fixture, a hydraulic system device, an abrasive circulation device and a workbench, the magnetic field generating device is fixed on the precision displacement platform, one end of the abrasive circulation device is connected to the fixture through a check valve, and the other end is connected to the hydraulic system device through a connecting rod and a rod joint, the magnetic field generating device comprises a pair of electromagnetic coils, a bolt 1, a support rod, a bolt 2, an inner ring frame, an outer ring frame, a magnetic pole The outer ring frame has a magnetic core sliding groove on the inner side, the upper end of the magnetic core is connected to the outer ring frame by bolts 2, and the lower end is connected to the upper end of the triangular fixing member by bolts 3. The electromagnetic coils are arranged in pairs and in parallel on the magnetic core. The triangular fixing member is installed on the inner ring frame by bolts 3. The outer ring frame is connected to the inner ring frame by support rods, bolts 5 and bolts 2. The four magnetic pole sleeves are fastened to the lower part of the triangular fixing member by bolts 1 in a circumferentially evenly distributed manner. The magnetic field generating device is fixed by bolts 4. The abrasive circulation device comprises a servo motor, a timing belt, a bearing, a connecting shaft, a three-jaw chuck, a bolt 6, a motor bracket, a base and a screw. The three-jaw chuck is connected to the connecting shaft by a bolt 6, and the connecting shaft is fixed to the bearing by a screw. The timing belt cooperates with the connecting shaft through a key connection. The servo motor drives the three-jaw chuck to rotate. The abrasive circulation device comprises a rotary joint, a check valve, an abrasive storage cylinder, a bracket 1, a connecting rod, an abrasive stirring cylinder, a hose and a slurry pump. The check valve is installed at the inlet and outlet of the abrasive storage cylinder. The check valve is connected to the workpiece through a rotary joint and a connecting rod. One end of the workpiece is installed on a three-jaw chuck, and the other end is connected to an abrasive mixing cylinder through a rotary joint and a hose. One end of the slurry pump is connected to the abrasive mixing cylinder through a hose, and the other end is connected to an abrasive storage cylinder. The abrasive mixing cylinder is fixed to the bracket 1 by bolts 6. The hydraulic system device includes a rod joint, a hydraulic cylinder, a bracket 2, an oil tank and a hydraulic pump. One end of the hydraulic pump is connected to the oil tank through a hose, and the other end is connected to the hydraulic cylinder. The other end of the hydraulic cylinder is connected to the abrasive storage cylinder through a rod joint.

[0005] The present invention provides a processing method provided by a circular tube inner surface polishing device controlled by coupling of an electromagnetic coil and a permanent magnet:

[0006] (1) The workpiece is fixed by a three-jaw chuck (3-5), a workpiece support frame (1-2) and a rotary joint (1-1), and a motor drives the three-jaw chuck (3-5) and the rotary joint (1-1) to rotate, so that the workpiece (1-5) rotates;

[0007] (2) placing the magnetic polishing medium in the abrasive stirring tank (1-14), and sucking the magnetic polishing medium into the abrasive storage tank (1-8) through the slurry pump (1-16);

[0008] (3) The angles of the paired electromagnetic coils (2-1) and the coupled magnetic field are adjusted according to the target area to be processed, and the paired electromagnetic coils (2-1) are coupled with the permanent magnets (2-11) to generate a magnetic field with a high magnetic field gradient and a strong magnetic field force to act on the processing area, thereby improving the processing efficiency;

[0009] (4) The magnetic field generating device (1-3) is driven by the precision displacement platform (1-4) to move to the entrance of the magnetic polishing medium of the workpiece (1-5), and at the same time, the hydraulic system device provides pressure to allow the magnetic polishing medium to enter the inner pipe of the workpiece (1-5). The precision displacement platform (1-4) drives the magnetic field generating device (1-3) to perform feeding movement, so that the formed flexible protrusion of the polishing medium generates relative movement with the target area, thereby achieving material removal;

[0010] (5) The current and frequency values ​​of the paired electromagnetic coils (2-1) are changed in real time, the force applied to the magnetic polishing medium and the shape of the polishing medium are dynamically adjusted, and the rotation of the three-jaw chuck (3-5) and the feeding of the precision displacement platform (1-4) are coordinated to form the control of the motion trajectory, thereby realizing the localized and intelligent polishing of the inner surface of the workpiece (1-5).

[0011] The beneficial effects of the present invention are:

[0012] 1. The invention discloses a circular tube inner surface polishing device controlled by coupling an electromagnetic coil and a permanent magnet. The paired electromagnetic coils are arranged in pairs and in parallel on the magnetic core. Compared with a single coil, when an alternating current of the same direction, magnitude and frequency is applied for excitation, the paired electromagnetic coils can generate a greater magnetic field strength and magnetic field gradient, thereby avoiding the problem of high heat generation when a single electromagnetic coil provides the required magnetic field strength, ensuring that the polishing medium and abrasive particles are not affected by heat, and improving the polishing efficiency and stability. 2. The invention discloses a circular tube inner surface polishing device controlled by coupling an electromagnetic coil and a permanent magnet. Through the coupling control method of paired electromagnetic coils and permanent magnets, the direction, magnitude and frequency of the alternating current passed into the paired electromagnetic coils are changed, and the magnetic field force and magnetic field gradient of the polishing position are adjusted in real time. The paired electromagnetic coils dominate the magnetic field gradient of the processing area, and the combination of the permanent magnets increases the magnetic field strength of the processing area, thereby regulating the morphology of the magnetic polishing medium and realizing targeted control of complex surface polishing. 3. The circular tube inner surface polishing device controlled by coupling of an electromagnetic coil and a permanent magnet described in the present invention regulates the direction of the alternating current passed into the paired electromagnetic coils to generate magnetic lines of force in the same direction as the permanent magnet, forming magnetic field coupling, and deploys different magnetic pole arrangements to form different magnetic line arrangements, such as forming 4-way magnetic lines of force, 1-way magnetic lines of force and 2-way magnetic lines of force, to achieve control of different magnetic field processing areas, and at the same time change the angle between the paired electromagnetic coils to further regulate the magnetic field action area, such as forming a 45° single-way magnetic line of force, and coordinate the motion control of the three-jaw chuck and the precision displacement platform to enable the magnetic polishing medium to form a targeted motion trajectory, thereby achieving targeted and localized intelligent polishing of the inner surface of the workpiece. 4. The present invention describes a circular tube inner surface polishing device controlled by coupling of an electromagnetic coil and a permanent magnet. The four permanent magnets can form 16 circularly evenly distributed arrangement patterns according to different magnetic pole allocations. The two magnetic pole polarities (N pole and S pole) of the combined paired electromagnetic coils can generate 32 types of coupled magnetic fields in the polishing area, forming different distributions of magnetic lines of force, thereby achieving efficient and high-quality processing of curved surfaces, flat surfaces, and grooved surfaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The invention discloses an overall structural diagram of a device and method for polishing the inner surface of a round tube controlled by coupling of an electromagnetic coil and a permanent magnet.

[0014] Figure 2 The present invention is a schematic structural diagram of a magnetic field generating device of a circular tube inner surface polishing device and method controlled by coupling of an electromagnetic coil and a permanent magnet.

[0015] Figure 3 The invention discloses a fixture structure schematic diagram of a device and method for polishing the inner surface of a round tube controlled by coupling of an electromagnetic coil and a permanent magnet.

[0016] Figure 4It is a schematic diagram of the distribution of magnetic lines of force in different polishing areas of a circular tube inner surface polishing device and method controlled by coupling of an electromagnetic coil and a permanent magnet according to the present invention.

[0017] Figure 5 It is a schematic diagram of the distribution of magnetic lines of force of different coupled magnetic fields of a circular tube inner surface polishing device and method controlled by coupling of an electromagnetic coil and a permanent magnet according to the present invention. DETAILED DESCRIPTION

[0018] Specific implementation method 1: Combination Figure 1 , Figure 2 , Figure 3The device described in this embodiment includes a workpiece support frame (1-2), a magnetic field generating device (1-3), a precision displacement platform (1-4), a workpiece (1-5), a fixture (1-6), a hydraulic system device, an abrasive circulation device and a workbench (1-19). The magnetic field generating device (1-3) is fixed on the precision displacement platform (1-4). One end of the abrasive circulation device is connected to the fixture (1-6) through a check valve (1-7), and the other end is connected to the hydraulic system device through a connecting rod (1-10) and a rod joint (1-11). The magnetic field generating device (1-3) includes a pair of electromagnetic coils (2-1), a bolt 1 (2-2), a support rod (2-3), a bolt 2 (2-4), an inner ring frame (2- 5), an outer ring frame (2-6), a magnetic pole sleeve (2-7), a magnetic core (2-8), a triangular fixing member (2-9), a bolt 3 (2-10), a permanent magnet (2-11), a bolt 4 (2-12) and a bolt 5 (2-13), the inner side of the outer ring frame (2-6) is provided with a magnetic core sliding groove, the upper end of the magnetic core (2-8) is connected to the outer ring frame (2-6) by a bolt 2 (2-4), and the lower end is connected to the upper end of the triangular fixing member (2-9) by a bolt 3 (2-10), the paired electromagnetic coils (2-1) are arranged in pairs and in parallel on the magnetic core (2-8), the triangular fixing member (2-9) is installed on the inner ring frame (2-5) by a bolt 3 (2-10), and the outer ring frame (2-6) is connected to the outer ring frame (2-6) by a support rod (2-3 ), bolts 5 (2-13) and bolts 2 (2-4) are connected to the inner ring frame (2-5), the four pole sleeves (2-7) are fastened to the lower part of the triangular fixing member (2-9) by bolts 1 (2-2) in a circumferentially evenly distributed manner, the magnetic field generating device (1-3) is fixed to the precision displacement platform (1-4) by bolts 4 (2-12), the fixture (1-6) includes a servo motor (3-1), a synchronous belt (3-2), a bearing (3-3), a connecting shaft (3-4), a three-jaw chuck (3-5), bolts 6 (3-6), a motor bracket (3-7), a base (3-8) and screws (3-9), the three-jaw chuck (3-5) is connected to the connecting shaft (3-4) by bolts 6 (3-6), the The connecting shaft (3-4) is fixed to the bearing (3-3) by means of a screw (3-9); the synchronous belt (3-2) is matched with the connecting shaft (3-4) by means of a key connection; the servo motor (3-1) drives the three-jaw chuck (3-5) to rotate; the abrasive circulation device comprises a rotary joint (1-1), a check valve (1-7), an abrasive storage cylinder (1-8), a bracket 1 (1-9), a connecting rod (1-10), an abrasive stirring cylinder (1-14), a hose (1-15) and a slurry pump (1-16); the check valve (1-7) is installed at the inlet and outlet of the abrasive storage cylinder (1-8); the check valve (1-7) is connected to the workpiece (1-5) by means of a rotary joint (1-1) and a connecting rod (1-10);One end of the workpiece (1-5) is mounted on the three-jaw chuck (3-5), and the other end is connected to the abrasive stirring cylinder (1-14) via a rotary joint (1-1) and a hose (1-15). One end of the slurry pump (1-16) is connected to the abrasive stirring cylinder (1-14) via a hose (1-15), and the other end is connected to the abrasive storage cylinder (1-8). The abrasive stirring cylinder (1-14) is fixed to the bracket 1 (1-9) via a bolt 6 (3-6). ), the hydraulic system device comprises a rod joint (1-11), a hydraulic cylinder (1-12), a bracket 2 (1-13), an oil tank (1-17) and a hydraulic pump (1-18), one end of the hydraulic pump (1-18) is connected to the oil tank (1-17) through a hose (1-15), and the other end is connected to the hydraulic cylinder (1-12), and the other end of the hydraulic cylinder (1-12) is connected to the abrasive storage cylinder (1-8) through a rod joint (1-11).

[0019] Specific implementation method 2: Combination Figure 1 , Figure 2 , Figure 3 The present embodiment describes the use of the magnetic field generating device (1-3) in conjunction with a precision motion platform (1-4) and a fixture (1-6). The paired electromagnetic coils (2-1) are arranged in pairs and in parallel on a magnetic core (2-8). When an alternating current of the same direction, magnitude and frequency is applied for excitation, the paired electromagnetic coils (2-1) can generate a greater magnetic field strength and a greater magnetic field gradient than a single coil, thereby avoiding the problem of high heat generation when a single electromagnetic coil provides the required magnetic field strength, ensuring that the polishing medium and abrasive particles are not affected by heat, and improving polishing efficiency and stability. The rest is the same as the first specific embodiment.

[0020] Specific implementation method three: Combination Figure 1 , Figure 2 The present embodiment describes that the paired electromagnetic coils (2-1) and the permanent magnets (2-11) are coupled and controlled in such a way that the paired electromagnetic coils (2-1) dominate the magnetic field gradient in the processing area, and the combination of the permanent magnets (2-11) increases the magnetic field strength in the processing area, changes the direction and frequency of the alternating current passed through the paired electromagnetic coils (2-1), adjusts the magnetic field force and magnetic field gradient at the polishing position in real time, regulates the morphology of the magnetic polishing medium, and realizes targeted control of complex surface polishing. The rest is the same as the first or second specific implementation method.

[0021] Specific implementation method four: Combination Figure 4The present embodiment describes that by regulating the direction of the alternating current passed through the paired electromagnetic coils (2-1), magnetic lines of force in the same direction as the permanent magnets (2-11) are generated to form magnetic field coupling, and different magnetic pole arrangements are deployed to form four magnetic lines of force (4-1), one magnetic line of force (4-2) and two magnetic lines of force (4-3), thereby achieving control of different magnetic field processing areas. The four magnetic lines of force (4-1) can achieve the polishing of the inner surface of the entire circular tube, the one magnetic line of force (4-2) can achieve the polishing of the inner surface of a quarter of the circular tube, and the two magnetic lines of force (4-3) can achieve the polishing of the inner surface of a quarter of the circular tube. The magnetic lines of force (4-3) can achieve polishing of one-half of the inner surface of the circular tube, and at the same time, changing the angle between the paired electromagnetic coils (2-1) can further regulate the magnetic field action area, such as forming a 45° single-path magnetic line of force (4-4), and coordinating the motion control of the three-jaw chuck (3-5) and the precision displacement platform (1-4), so that the magnetic polishing medium can form a targeted motion trajectory, thereby achieving intelligent polishing of the targeted localized inner surface of the workpiece; when polishing the entire inner surface of the circular tube, the paired electromagnetic coils (2-1) are at an angle of 90°, and the paired The lower end of the electromagnetic coil (2-1) 1 is coupled to an N pole, the lower end of the paired electromagnetic coil (2-1) 2 is coupled to an S pole, the lower end of the paired electromagnetic coil (2-1) 3 is coupled to an N pole, and the lower end of the paired electromagnetic coil (2-1) 4 is coupled to an S pole, thereby forming four magnetic lines of force (4-1); when polishing the inner surface of a quarter-circular tube or a half-circular tube, a specific pair of electromagnetic coils (2-1) and a permanent magnet (2-11) can be selected according to different processing areas. For example, the lower end of the paired electromagnetic coil (2-1) 1 is coupled to an N pole, the lower end of the paired electromagnetic coil (2-1) 2 is coupled to an S pole, the lower end of the paired electromagnetic coil (2-1) 3 is coupled to an N pole, and the lower end of the paired electromagnetic coil (2-1) 4 is coupled to an S pole, thereby forming four magnetic lines of force (4-1). The lower end of the magnetic coil (2-1) 2 is coupled to an S pole, the lower end of the paired electromagnetic coil (2-1) 4 is coupled to an S pole, and so on, forming one magnetic line of force (4-2) and two magnetic lines of force (4-3) respectively; when polishing any area of ​​the inner surface of the circular tube, the angle between the paired electromagnetic coils (2-1) can be changed, such as the lower end of the paired electromagnetic coil (2-1) 1 is coupled to an N pole, and the lower end of the paired electromagnetic coil (2-1) 2 is coupled to an S pole, forming a 45° single magnetic line of force (4-4), and the rest is the same as the specific implementation mode one, two or three.

[0022] Specific implementation method five: Combination Figure 5It is explained that the four permanent magnets (2-11) described in this embodiment can form 16 kinds of circumferentially evenly distributed arrangements according to different magnetic pole arrangements, and the two magnetic pole polarities (N pole and S pole) of the combined paired electromagnetic coils can generate 32 types of coupled magnetic fields in the polishing area, forming different magnetic line distributions, such as NSN arrangement (5-1) and paired NS arrangement (5-2), to achieve efficient and high-quality processing of curved surfaces, planes, and groove surfaces; the lower end of the paired electromagnetic coil (2-1) 1 is coupled to the N pole The lower ends of the paired electromagnetic coils (2-1) 2 are coupled as S poles, and the lower ends of the paired electromagnetic coils (2-1) 3 are coupled as N poles, forming an NSN arrangement (5-1); the lower ends of the paired electromagnetic coils (2-1) 1 are coupled as N poles, the lower ends of the paired electromagnetic coils (2-1) 2 are coupled as S poles, the lower ends of the paired electromagnetic coils (2-1) 3 are coupled as S poles, and the lower ends of the paired electromagnetic coils (2-1) 4 are coupled as N poles, forming a paired NS arrangement (5-2), and the rest are the same as the specific embodiments one, two, three or four.

[0023] Specific implementation method six: Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 The polishing steps of this embodiment using the device described in any one of the embodiments 1, 2, 3, 4 or 5 are as follows:

[0024] (1) The workpiece is fixed by a three-jaw chuck (3-5), a workpiece support frame (1-2) and a rotary joint (1-1), and a motor drives the three-jaw chuck (3-5) and the rotary joint (1-1) to rotate, so that the workpiece (1-5) rotates;

[0025] (2) placing the magnetic polishing medium in the abrasive stirring tank (1-14), and sucking the magnetic polishing medium into the abrasive storage tank (1-8) through the slurry pump (1-16);

[0026] (3) The angles of the paired electromagnetic coils (2-1) and the coupled magnetic field are adjusted according to the target area to be processed, and the paired electromagnetic coils (2-1) are coupled with the permanent magnets (2-11) to generate a magnetic field with a high magnetic field gradient and a strong magnetic field force to act on the processing area, thereby improving the processing efficiency;

[0027] (4) The magnetic field generating device (1-3) is driven by the precision displacement platform (1-4) to move to the entrance of the magnetic polishing medium of the workpiece (1-5), and at the same time, the hydraulic system device provides pressure to allow the magnetic polishing medium to enter the inner pipe of the workpiece (1-5). The precision displacement platform (1-4) drives the magnetic field generating device (1-3) to perform feeding movement, so that the formed flexible protrusion of the polishing medium generates relative movement with the target area, thereby achieving material removal;

[0028] (5) changing the current and frequency values ​​of the paired electromagnetic coils (2-1) in real time, dynamically adjusting the force applied to the magnetic polishing medium and the shape of the polishing medium, coordinating the rotation of the three-jaw chuck (3-5) and the feeding of the precision displacement platform (1-4), forming the regulation of the motion trajectory, and realizing the localized and intelligent polishing of the inner surface of the workpiece (1-5);

[0029] (6) After polishing is completed, the power supply to the paired electromagnetic coils (2-1) is stopped and the operation of other systems is stopped, so that the magnetic polishing medium in the polishing processing area stops moving relative to the workpiece, the force is eliminated, and the polishing process is stopped.

Claims

1. A round tube inner surface polishing device controlled by coupling of an electromagnetic coil and a permanent magnet, characterized in that: The device comprises a workpiece support frame (1-2), a magnetic field generating device (1-3), a precision displacement platform (1-4), a workpiece (1-5), a fixture (1-6), a hydraulic system device, an abrasive circulation device and a workbench (1-19); the magnetic field generating device (1-3) is fixed on the precision displacement platform (1-4); one end of the abrasive circulation device is connected to the fixture (1-6) via a check valve (1-7); the other end is connected to the hydraulic system device via a connecting rod (1-10) and a rod joint (1-11); the magnetic field generating device (1-3) comprises a pair of electromagnetic coils (2-1), a bolt 1 (2-2), a support rod (2-3), a bolt 2 (2-4), an inner ring frame (2-5), and an outer ring frame (2-6). , a magnetic pole sleeve (2-7), a magnetic core (2-8), a triangular fixing member (2-9), a bolt 3 (2-10), a permanent magnet (2-11), a bolt 4 (2-12) and a bolt 5 (2-13); a magnetic core sliding groove is opened on the inner side of the outer ring frame (2-6); the upper end of the magnetic core (2-8) is connected to the outer ring frame (2-6) by a bolt 2 (2-4); the lower end is connected to the upper end of the triangular fixing member (2-9) by a bolt 3 (2-10); the paired electromagnetic coils (2-1) are arranged in pairs and in parallel on the magnetic core (2-8); the triangular fixing member (2-9) is installed on the inner ring frame (2-5) by a bolt 3 (2-10); the outer ring frame (2-6) is connected by a support rod (2-3), a bolt 5 (2-13) and a bolt 2 (2-4) is connected to the inner ring frame (2-5), the four magnetic pole sleeves (2-7) are fastened to the lower part of the triangular fixing member (2-9) by bolts 1 (2-2) in a circumferentially evenly distributed manner, the magnetic field generating device (1-3) is fixed to the precision displacement platform (1-4) by bolts 4 (2-12), the fixture (1-6) includes a servo motor (3-1), a synchronous belt (3-2), a bearing (3-3), a connecting shaft (3-4), a three-jaw chuck (3-5), bolts 6 (3-6), a motor bracket (3-7), a base (3-8) and screws (3-9), the three-jaw chuck (3-5) is connected to the connecting shaft (3-4) by bolts 6 (3-6), and the connecting shaft (3-4) is fixed by screws (3-9) On the bearing (3-3), the synchronous belt (3-2) is matched with the connecting shaft (3-4) through a key connection, the servo motor (3-1) drives the three-jaw chuck (3-5) to rotate, the abrasive circulation device comprises a rotary joint (1-1), a check valve (1-7), an abrasive storage cylinder (1-8), a bracket 1 (1-9), a connecting rod (1-10), an abrasive stirring cylinder (1-14), a hose (1-15) and a slurry pump (1-16), the check valve (1-7) is installed at the inlet and outlet of the abrasive storage cylinder (1-8), the check valve (1-7) is connected to the workpiece (1-5) through the rotary joint (1-1) and the connecting rod (1-10), and one end of the workpiece (1-5) is installed on the three-jaw chuck (3-5).The other end is connected to the abrasive mixing cylinder (1-14) through a rotating joint (1-1) and a hose (1-15); one end of the slurry pump (1-16) is connected to the abrasive mixing cylinder (1-14) through a hose (1-15), and the other end is connected to the abrasive storage cylinder (1-8); the abrasive mixing cylinder (1-14) is fixed to the bracket 1 (1-9) through a bolt 6 (3-6); the hydraulic system device comprises a rod joint (1-11), a hydraulic cylinder (1-12), a bracket 2 (1-13), an oil tank (1-17) and a hydraulic pump (1-18); one end of the hydraulic pump (1-18) is connected to the oil tank (1-17) through a hose (1-15), and the other end is connected to the hydraulic cylinder (1-12); the other end of the hydraulic cylinder (1-12) is connected to the abrasive storage cylinder (1-8) through a rod joint (1-11).

2. The device for polishing the inner surface of a round tube controlled by coupling of an electromagnetic coil and a permanent magnet according to claim 1, characterized in that: The paired electromagnetic coils (2-1) are arranged in pairs and in parallel on the magnetic core (2-8). When an alternating current excitation of the same direction, magnitude and frequency is applied, the paired electromagnetic coils (2-1) can generate a greater magnetic field strength and a greater magnetic field gradient than a single coil, thereby avoiding the problem of high heat generation when a single electromagnetic coil provides the required magnetic field strength, ensuring that the polishing medium and abrasive particles are not affected by heat, and improving the polishing efficiency and stability.

3. A tube inner surface polishing device controlled by coupling of electromagnetic coil and permanent magnet according to claim 1 or 2, characterized in that: Through the coupling control method of the paired electromagnetic coils (2-1) and the permanent magnets (2-11), the paired electromagnetic coils (2-1) dominate the magnetic field gradient of the processing area, and the combination of the permanent magnets (2-11) increases the magnetic field strength of the processing area, changes the direction and frequency of the alternating current passed into the paired electromagnetic coils (2-1), adjusts the magnetic field force and magnetic field gradient of the polishing position in real time, regulates the shape of the magnetic polishing medium, and realizes targeted control of complex surface polishing.

4. A tube inner surface polishing device controlled by coupling of an electromagnetic coil and a permanent magnet according to claim 1 or 2, characterized in that: By regulating the direction of the alternating current passed through the paired electromagnetic coils (2-1), magnetic lines of force in the same direction as the permanent magnets (2-11) are generated to form magnetic field coupling. By adjusting different magnetic pole arrangements, four magnetic lines of force (4-1), one magnetic line of force (4-2) and two magnetic lines of force (4-3) can be formed to control different magnetic field processing areas. The four magnetic lines of force (4-1) can polish the entire inner surface of the circular tube, the one magnetic line of force (4-2) can polish the inner surface of a quarter of the circular tube, and the two magnetic lines of force (4-3) can polish the inner surface of one-half of the circular tube. By changing the angle between the paired electromagnetic coils (2-1) at the same time, the magnetic field action area can be further regulated, such as forming a 45° single magnetic line of force (4-4). By coordinating the motion control of the three-jaw chuck (3-5) and the precision displacement platform (1-4), the magnetic polishing medium can form a targeted motion trajectory, thereby realizing intelligent polishing of the targeted and localized inner surface of the workpiece.

5. A tube inner surface polishing device controlled by coupling of electromagnetic coil and permanent magnet according to claim 1 or 2, characterized in that: The four permanent magnets (2-11) can form 16 circumferentially evenly distributed arrangements according to different magnetic pole arrangements, and the two magnetic pole polarities (N pole and S pole) of the combined paired electromagnetic coils can generate 32 types of coupled magnetic fields in the polishing area, forming different magnetic line distributions, such as NSN arrangement (5-1) and paired NS arrangement (5-2), which can achieve efficient and high-quality processing of curved surfaces, flat surfaces, and groove surfaces.

6. The polishing method of a round tube inner surface polishing device using a coupling control of an electromagnetic coil and a permanent magnet according to claim 1, 2, 3, 4 or 5, characterized in that: The polishing method comprises the following steps: (1) The workpiece is fixed by a three-jaw chuck (3-5), a workpiece support frame (1-2) and a rotary joint (1-1), and a motor drives the three-jaw chuck (3-5) and the rotary joint (1-1) to rotate, so that the workpiece (1-5) rotates; (2) placing the magnetic polishing medium in the abrasive stirring tank (1-14), and sucking the magnetic polishing medium into the abrasive storage tank (1-8) through the slurry pump (1-16); (3) The angles of the paired electromagnetic coils (2-1) and the coupled magnetic field are adjusted according to the target area to be processed, and the paired electromagnetic coils (2-1) are coupled with the permanent magnets (2-11) to generate a magnetic field with a high magnetic field gradient and a strong magnetic field force to act on the processing area, thereby improving the processing efficiency; (4) The magnetic field generating device (1-3) is driven by the precision displacement platform (1-4) to move to the entrance of the magnetic polishing medium of the workpiece (1-5), and at the same time, the hydraulic system device provides pressure to allow the magnetic polishing medium to enter the inner pipe of the workpiece (1-5). The precision displacement platform (1-4) drives the magnetic field generating device (1-3) to perform feeding movement, so that the formed flexible protrusion of the polishing medium generates relative movement with the target area, thereby achieving material removal; (5) The current and frequency values ​​of the paired electromagnetic coils (2-1) are changed in real time, the force applied to the magnetic polishing medium and the shape of the polishing medium are dynamically adjusted, and the rotation of the three-jaw chuck (3-5) and the feeding of the precision displacement platform (1-4) are coordinated to form the control of the motion trajectory, thereby realizing the localized and intelligent polishing of the inner surface of the workpiece (1-5).

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