CN118024031A - Magnetorheological polishing device and method for small pipe variable-diameter large-length-diameter-ratio inner hole - Google Patents

Abstract

The invention discloses a magnetorheological polishing device and a magnetorheological polishing method for an inner hole with a small pipe variable diameter and a large length-diameter ratio, and relates to the technical field of ultra-precision machining. The method comprises the steps of preparing magnetorheological fluid, injecting the magnetorheological fluid into a hole of a target workpiece through a delivery pump, stirring to enable the fluid to flow and not to precipitate, enabling the magnetorheological fluid to form a flexible polishing film in the hole by a multi-magnetic-field generating device, enabling the target workpiece to axially reciprocate by a reciprocating mechanism, enabling the multi-magnetic-field generating device to rotate around an axis of the magnetic-field generating device by a magnetic-field driving system, and finally achieving approximately uniform polishing pressure generated on the inner wall, thereby finishing high-quality and high-efficiency polishing. The polishing device is suitable for polishing long and thin through holes with different sizes and reducing capillaries, solves the difficult problem that the capillaries are easy to deform and jump in the processing process, and is beneficial to improving the polishing efficiency.

Description

Magnetorheological polishing device and method for small pipe variable-diameter large-length-diameter-ratio inner hole

Technical Field

The invention belongs to the technical field of ultra-precise machining, and particularly relates to a magnetorheological polishing device and method for an inner hole with a small pipe and a variable diameter and a large length-diameter ratio, which are particularly suitable for polishing through holes with a variable diameter and a large length-diameter ratio.

Background

The application of the fine tube (the inner diameter is smaller than 10mm, the length-diameter ratio is larger than 20) is increasingly wide, such as a conveying pipeline used by a refrigerating unit, core parts of a high-end biochemical analyzer and a chemiluminescent immunoassay analyzer, namely a sample adding needle, a capillary tube used by biological detection analysis, a minimally invasive catheter used by medical industry and the like. Although the performance requirements of different fields are different, most of the fields want the inner wall of the fine pipe to have higher smoothness, and especially the inner hole diameter change is required to be smooth enough to reduce cleaning residues and avoid cross contamination of liquid.

At present, the high-quality inner hole of the small pipe with large length-diameter ratio is generally polished by adopting an abrasive flow or magnetic particle grinding process to remove burrs on the inner wall of the pipe. The abrasive flow polishing can realize polishing of various complex inner cavity structures and inner channels by means of good profiling characteristics and flow characteristics of fluid, but in the processing process, the pressure of an abrasive medium on the surface of a target workpiece is in the MPa level, the polishing effect is obvious when the abrasive medium passes through a variable-section and variable-curvature channel, the polishing effect of the surface of a straight channel is poor, and a controllable polishing method aiming at removing a homogenized material is required to be provided, and the problem of polishing of a thin-wall low-rigidity structural member is solved. The magnetic particle grinding utilizes magnetic field characteristics to assist the abrasive particles to polish, so that the inner hole polishing efficiency and the processing surface quality can be effectively improved, and the method has the advantages of higher self-adaptability, no need of tool compensation and the like.

At present, the polishing technology for reducing deep micropores has reached the bottleneck, and how to improve the processing efficiency while guaranteeing the quality and uniformity of the processed surface becomes a key technical problem to be solved in the field.

In the prior art, the magnetorheological polishing technology can reduce the surface roughness of the device to below 1nm, can obtain better surface and subsurface quality, has wide range of processable materials, is mostly used for polishing the outer surfaces of large-scale elements and micro devices, and has less and immature researches on polishing the inner walls of small tubes such as reducing sample adding needles, capillaries and the like.

Disclosure of Invention

The present invention aims to solve the above technical problems to a certain extent. Therefore, the invention provides a magnetorheological polishing device and a magnetorheological polishing method for an inner hole with a small pipe and a variable diameter and a large length-diameter ratio, which are used for solving the problems that a capillary tube is easy to deform and jump in the processing process of the prior art and a target workpiece is difficult to perform rotary motion in the processing process so as to cause uneven quality of a processing surface.

In order to achieve the above object, the present invention provides the following solutions: a magnetorheological polishing device and method for a small pipe variable-diameter large-length-diameter-ratio inner hole comprises the following steps:

The device comprises a device body, a plurality of working tables and a plurality of control units, wherein the working tables are provided with a plurality of working tables with different horizontal heights, and a central hole with a coaxial center is formed in the center of each working table;

The reciprocating mechanism comprises a guide rail vertically fixedly connected to the device body, a sliding block sliding on the guide rail, a ball screw driving the sliding block to reciprocate, a coupler and a servo motor;

The clamping assembly is fixedly connected to the sliding block and provided with an ER chuck coaxially arranged with the central hole, and the ER chuck is used for clamping a target workpiece;

The multi-magnetic-field generating device is rotationally connected between the two work tables and is provided with a magnetic field channel for accommodating a target workpiece to pass through, the magnetic field channel is coaxial with the central hole, a plurality of layers of turntables are arranged outside the magnetic field channel, and a pair of permanent magnets are fixedly connected on each turntable;

The magnetic field driving system is in transmission connection with the multi-magnetic field generating device and controls the magnetic field to rotate;

And the magnetorheological polishing solution supply circulation system is connected with the target workpiece and is used for circularly supplying the magnetorheological solution to the inner hole of the target workpiece.

Preferably, the multi-magnetic field generating device comprises a pressing plate, a connecting rod, a connecting shaft, tapered roller bearings, a turntable and permanent magnets, wherein the turntable is connected through the connecting rod to form a multi-layer structure, the multi-layer structure is arranged in central holes of two work tables through an upper connecting shaft and a lower connecting shaft and the tapered roller bearings, and the permanent magnets are arranged on the turntable through the pressing plate and screws.

Preferably, the number of layers of the turntable is determined according to the length to be processed of the target workpiece, the rod length of the connecting rod and the reciprocating travel of the target workpiece, and the relation is as follows: c= (L-T)/l+1, where C is the number of layers, L is the length to be processed of the target workpiece, T is the reciprocating travel of the target workpiece, and L is the connecting rod length.

Preferably, the permanent magnets are symmetrically mounted on the turntable in a pair of N-S or S-N poles, each pair of poles being arranged in a manner of continuous 45 degrees of rotation.

Preferably, when the outer diameter of the target workpiece is smaller than 5mm, a pair of magnetic poles are arranged on each turntable; when the outer diameter of the target workpiece is between 5 and 10mm, two pairs of magnetic poles are arranged on each turntable, and the two pairs of magnetic poles are symmetrically arranged.

Preferably, the permanent magnet is an N35 permanent magnet as a magnetic field source.

Preferably, the magnetic field strength can be adjusted within the range of 0 to 0.45T by adjusting the installation position of the permanent magnet.

Preferably, the rotating speed range of the magnetic field driving system for driving the multi-magnetic field generating device to rotate is 0-1000 rpm, and the radial and axial circular runout of the turntable in the multi-magnetic field generating device are both within 0.01 mm.

The invention discloses the following technical effects:

The invention provides a magnetorheological polishing device and a magnetorheological polishing method for an inner hole with a small pipe and a variable diameter and a large length-diameter ratio, which are used for sufficiently improving the finish of the inner wall of the variable diameter deep micro hole, are suitable for polishing an elongated thin-wall through hole with an inner diameter smaller than 10mm and a variable diameter capillary, solve the difficult problem that the capillary is easy to deform and jump in the processing process due to low rigidity, and are beneficial to improving the polishing efficiency of the inner hole of a capillary-like part made of a non-ferromagnetic material.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic structural view of a magnetorheological polishing apparatus according to an embodiment of the present invention;

FIG. 2 is a schematic structural view of a reciprocating mechanism in a magnetorheological polishing apparatus according to an embodiment of the present invention;

FIG. 3 is a schematic view of a clamping assembly in a magnetorheological polishing apparatus according to an embodiment of the present invention;

FIG. 4 is a semi-sectional view of a multi-magnetic field generating device in a magnetorheological polishing apparatus according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of the operation of a magnetorheological polishing apparatus according to an embodiment of the present invention;

FIG. 6 is a graph showing the optimized magnetic field distribution of a pair of magnetic poles in a magnetorheological polishing apparatus according to an embodiment of the present invention.

1, A device body; 2. a reciprocating mechanism; 21. a ball screw; 22. a guide rail; 23. a slide block; 24. a coupling; 25. a servo motor; 3. a clamping assembly; 31. a connecting piece; 32. an ER chuck; 33. a rubber bushing; 34. a lock nut; 35. a plastic bushing; 36. a plastic sliding bearing; 4. a multi-magnetic field generating device; 41. a permanent magnet; 42. a pressing plate; 43. a turntable; 44. a connecting rod; 45. a connecting shaft; 46. tapered roller bearings; 47. an end cap; 5. a magnetic field driving system; 51. a synchronous belt; 52. a belt wheel; 53. a stepping motor; 54. a motor support; 6. supplying the magnetorheological polishing solution to a circulating system; 61. a transfer pump; 62. an electric stirrer; 63. a liquid container; 64. a clamp; 65. a hose clamp; 66. a hose; 7. a target workpiece.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In order that the above-recited objects, features and advantages of the present invention will become more readily apparent, a more particular description of the invention will be rendered by reference to the appended drawings and appended detailed description.

Example 1:

Referring to fig. 1, the invention provides a magnetorheological polishing device and a magnetorheological polishing method for an inner hole with a small pipe variable diameter and a large length-diameter ratio, which comprise a device body 1, a reciprocating mechanism 2, a clamping assembly 3, a multi-magnetic-field generating device 4, a magnetic-field driving system 5 and a magnetorheological polishing liquid supply circulating system 6. The device comprises a device body 1, a lower device body and a control device, wherein the device body 1 comprises a workbench with a three-layer horizontal plane structure, the workbench is of an E-shaped structure and comprises an upper layer, a middle layer and a lower layer, and central holes are formed in the centers of the upper layer workbench, the middle layer workbench and the lower layer workbench; the device body 1 further comprises a vertical body positioned at the rear side of the workbench, a reciprocating mechanism 2 is arranged on the vertical body, and the reciprocating mechanism 2 is connected with the clamping assembly 3 in a sliding manner; the multi-magnetic field generating device 4 is fixedly connected between the upper-layer workbench and the middle-layer workbench, a magnetic field channel for accommodating a target workpiece 7 to pass through is formed in the multi-magnetic field generating device 4, and the magnetic field channel is coaxial with a central hole on the three-layer workbench; the magnetic field driving system 5 is arranged on one side of the device body 1 and provides rotary driving force for the multi-magnetic field generating device 4; the magnetorheological polishing fluid is supplied to the circulation system 6 for pumping the polishing fluid into the target workpiece 7 and powering the circulating flow of the polishing fluid.

Specifically, as shown in fig. 2, the reciprocating mechanism 2 includes a ball screw 21, a guide rail 22, a slider 23, a coupling 24, and a servo motor 25, where the ball screw 21 and the guide rail 22 are precisely and vertically mounted on the device body 1 by screws (not shown), and at the same time, the heights and positions of the ball screw 21 and the guide rail 22 need to be precisely set, so that the center hole of the truncated cone of the connecting piece 31 is coaxial with the center hole of the device body 1, the coaxiality is not less than 0.01mm, and it is also ensured that the movable travel of the slider 23 is not less than the length of the connecting rod 44, and further that the connecting piece 31 will not interfere with movement; the servo motor 25 drives the ball screw 21 through the coupling 24, and the slider 23 is driven by the ball screw 21 to reciprocate on the guide rail 22, so that the target workpiece 7 (slender tube) is axially reciprocated.

Further optimizing the scheme, the heavy positioning precision of the reciprocating mechanism 2 is 0.1mm, the stroke is 300mm, and the reciprocating speed is 0-40 mm/s;

Specifically, as shown in fig. 3, the clamping assembly 3 includes a connecting member 31, an ER chuck 32, a rubber bushing 33, a lock nut 34, a plastic bushing 35, and a plastic sliding bearing 36, wherein the connecting member 31 is connected to the slider 23 by a screw (not shown), and the ER chuck 32 is placed in the connecting member 31 and then is tightened by the lock nut 34; the plastic sliding bearing 36 and the plastic bush 35 are connected on a round table below the device body 1 through screws (not shown), and the plastic bush 35 is contacted with the target workpiece 7; the ER collet 32 and the plastic bushing 35 are selected according to the outer diameter of the target workpiece 7, and if the diameter of the target workpiece 7 is too small, for example, the outer diameter is smaller than 1mm, one rubber bushing 33 is added to cooperate with the ER collet 32, so as to complete the clamping of the target workpiece 7 with a very small outer diameter.

Further optimizing scheme, the ER chuck 32 clamps the target workpiece 7, and for target workpieces 7 with different diameters, the ER chuck 32 can be replaced or a rubber bushing 33 is added to clamp and automatically center, so that the reciprocating mechanism 2 can drive the target workpiece 7 to axially reciprocate and linearly.

Specifically, as shown in fig. 4, the multi-magnetic field generating device 4 includes a permanent magnet 41, a pressing plate 42, a turntable 43, a connecting rod 44, a connecting shaft 45, a tapered roller bearing 46 and an end cover 47, the turntable 43 is connected by the connecting rod 44 to form a multi-layer structure, the layer number C of the multi-layer structure is set according to the length L to be processed of the target workpiece 7, the multi-layer structure is rounded upwards, and the determined relation of the layer number C is: c= (L-T)/l+1; wherein T is the reciprocating motion stroke of the target workpiece 7, and l is the length of the connecting rod 44; the target workpiece 7 needs to be kept long enough for clamping, the permanent magnet 41 is placed on the turntables 43 through the pressing plate 42 and the screws, and then each turntable 43 generates a magnetic field, namely a plurality of sections of magnetic fields are arranged on the target workpiece 7; the multilayer structure is arranged in the central hole of the workbench through the upper connecting shaft 45, the lower connecting shaft 45 and the tapered roller bearing 46, and the coaxiality between the multilayer structure and the central hole is ensured to be within 0.01 mm; the tapered roller bearing 46 above is in contact with the end cover 47, so that the multilayer structure is axially fixed.

In the present embodiment, more specifically, the multiple magnetic field generating device 4 includes 3 pairs of permanent magnets 41, 6 pressing plates 42, 3 turntables 43, 6 connecting rods 44, 2 connecting shafts 45, 2 tapered roller bearings 46, and one end cover 47;3 turntables 43 are connected through 6 connecting rods 44 to form a three-layer structure, and 3 pairs of permanent magnets 41 are respectively arranged on 3 turntables 43 through 6 pressing plates 42 and screws (not shown in the figure), namely 3 sections of magnetic fields are generated on a target workpiece 7; the three-layer structure is arranged in the central hole of the device body 1 through the upper connecting shaft 45, the lower connecting shaft 45 and the 2 tapered roller bearings 46, and the tapered roller bearings 46 contact with the end cover 47 above to realize the axial fixation of the three-layer structure.

According to a further optimization scheme, the permanent magnets 41 are symmetrically arranged on the turnplate 43 according to a pair of magnetic poles N-S or S-N, the pair of magnetic poles are arranged on the radial section and have obvious magnetic field gradients, so that the polishing film can smoothly rotate or flow, in addition, the symmetrically arranged pair of magnetic poles are equivalent to an auxiliary support, the transverse stress balance of the target workpiece 7 is realized, the local magnetic fields of the axial section of the inner hole can be uniformly distributed, the arrangement form of the pair of magnetic poles has obvious magnetic field gradients on the radial section, the situation that the flexible polishing film cannot rotate or flow due to complete solidification can be avoided, when the outer diameter of the target workpiece 7 is smaller than 5mm, the arrangement form of only one pair of magnetic poles is preferred for each layer of turnplate 43, the polishing quality of the inner wall is guaranteed, and when the outer diameter of the target workpiece 7 is between 5mm and 10mm, in order to further improve the polishing efficiency, the arrangement form of two pairs of magnetic poles can be selected for each layer of turnplate 43 under the condition that the polishing quality is not influenced; each pair of symmetrically installed magnetic poles is equivalent to an auxiliary support, so that the transverse stress balance of the target workpiece 7 and the uniform distribution of local magnetic fields of the axial section of the inner hole are realized.

According to a further optimization scheme, each pair of magnetic poles on the turntable 43 are required to be arranged in a continuous rotation mode by 45 degrees, so that continuous spiral movement of abrasive particles in the magnetorheological fluid is facilitated, and polishing efficiency and quality are improved; the permanent magnet 41 can slide and fix on the groove of the turntable 43 to adjust the magnetic field intensity on the inner wall of the target workpiece 7, so that the magnetorheological fluid can smoothly rotate and generate enough and uniform polishing pressure under the action of magnetic force, wherein the adjustable range of the magnetic field intensity is 0-0.45T.

According to a further optimization scheme, aiming at an inner hole of the reducing part of the target workpiece 7, the magnetic field intensity of the reducing part of the target workpiece 7 is adjusted by changing the connecting rods 44 with different rod lengths and adjusting the positions of the permanent magnets 41, so that gradient change of the magnetic field in the vertical direction and the polishing pressure of the inner wall of the reducing part under the influence of the fluid pressure are the same as those before the reducing are achieved, and uniform polishing and smooth transition of the inner wall of the reducing inner hole are achieved.

In a further optimization scheme, the permanent magnet 41 is an N35 permanent magnet 41 as a magnetic field source, in this embodiment, all other parts except the permanent magnet 41 are made of non-ferromagnetic materials, such as aluminum alloy, engineering plastic, etc., and if the structure has magnetism, demagnetization treatment or magnetic shielding protection should be performed.

Specifically, as shown in fig. 5, the magnetic field driving system 5 includes a timing belt 51, 2 pulleys 52, a stepping motor 53, a motor support 54, and a controller (not shown), and the reduction ratio is 2:1 to increase the torque of the connecting shaft 45; the 2 pulleys 52 are respectively connected with the connecting shaft 45 of the multi-magnetic-field generating device 4 and the stepping motor 53; the synchronous belt 51 is connected with the two belt pulleys 52, the installation height and the position of the stepping motor 53 are adjusted, the two belt pulleys 52 are guaranteed to be identical in installation height, and the synchronous belt 51 is tensioned; the controller can control the operation of the servo motor 25 and the stepper motor 53 simultaneously.

Further optimizing scheme, the rotating speed range of the stepping motor 53 is 0-2000 rpm, the rotating speed range of the multi-magnetic-field generating device 4 is 0-1000 rpm, and the radial and axial circular runout of the turntable 43 in the multi-magnetic-field generating device 4 is required to be within 0.01 mm.

Further optimizing scheme, the controller controls the operation of the multi-magnetic-field generating device 4 and the reciprocating mechanism 2, namely, the controller can simultaneously control the reciprocating axial motion of the target workpiece 7 and the rotating motion of the magnetic field, namely, the moving speed, the travel and the rotating speed, so that the magnetic field acting area is enlarged, the polished length of the target workpiece 7 is increased, the uniformity of the quality of the inner wall processing surface is improved, and the spiral line motion of abrasive particles is realized.

Specifically, as shown in fig. 5, the magnetorheological polishing fluid supply circulation system 6 includes a delivery pump 61, an electric stirrer 62, a fluid container 63, a clamp 64, a hose clamp 65, and a hose 66; the hose 66 is internally circulated with magnetorheological fluid, the hose 66 is firstly connected to the target workpiece 7 from the delivery pump 61, then is communicated to the liquid container 63 from the target workpiece 7, and finally is connected to the delivery pump 61 from the liquid container 63 to form a magnetorheological fluid circulation loop; the clamp 64 can clamp the hose 66 and the target workpiece 7, the hose clamp 65 is used for fixing the hose 66, and the electric stirrer 62 is fixed on the liquid container 63, so that the stirring speed can be controlled, and the magnetorheological fluid is not easy to precipitate.

Further optimizing scheme, the hydraulic pressure range provided by the conveying pump 61 is 0-4 MPa, and the flow range is 0-18L/min.

According to a further optimization scheme, the magnetorheological fluid is input into the target workpiece 7 by the conveying pump 61, and the generated fluid flow combines the reciprocating axial movement of the target workpiece 7 and the rotary movement of the multi-magnetic-field generating device 4 to form the compound movement of abrasive particles, namely the continuous spiral movement of the abrasive particles is realized, so that the omnibearing polishing of the inner wall to be processed of the target workpiece 7 is completed.

Example 2:

The embodiment 2 of the invention provides a magnetorheological polishing method for a small pipe variable-diameter large-length-diameter-ratio inner hole, which is implemented by applying the magnetorheological polishing device for the small pipe variable-diameter large-length-diameter-ratio inner hole, which is described in the embodiment 1, taking a stainless steel pipe as a target workpiece 7 as an example, wherein the length of the stainless steel pipe is 30cm, the inner diameter of the stainless steel pipe before non-reducing is 1mm, and the inner diameter of the stainless steel pipe after reducing is 0.7mm, and the specific operation steps are as follows:

Step S1, preparing magnetorheological fluid, namely preparing the magnetorheological fluid according to the existing preparation and application principle, pouring the prepared magnetorheological fluid into a fluid container 63, starting stirring, and ensuring that the magnetorheological fluid is not precipitated under the continuous stirring of an electric stirrer 62 so as to have the optimal polishing effect.

In some embodiments, the magnetorheological fluid is formulated with 36 percent by volume of the iron powder, 6 percent by volume of the silicon carbide or diamond abrasive particles, 57 percent by volume of the aqueous liquid, and the balance being the stabilizer.

Step S2, installing the target workpiece 7: one end of the target workpiece 7 passes through the ER chuck 32 or the rubber bushing 33 thereof, and the locking nut 34 is screwed down, so that the ER chuck 32 clamps the target workpiece 7, and the other end of the target workpiece 7 can pass through the plastic bushing 35, and then the reciprocating mechanism 2 can drive the target workpiece 7 to do axial reciprocating linear motion.

Step S3, setting a liquid loop: the rubber hose 66 is connected from the delivery pump 61 to the upper end of the target workpiece 7, then is communicated to the liquid container 63 from the lower end of the target workpiece 7, and finally is connected from the liquid container 63 to the delivery pump 61, simultaneously the hose 66 and the target workpiece 7 are clamped by the clamp 64, the hose 66 is fixed by the hose clamp 65, a certain length of the hose 66 is reserved to avoid interference in the movement process of the target workpiece 7, then the delivery pump 61 is started, and the flow is set according to the size of the target workpiece 7.

Step S4, distributing magnetic fields and adjusting the magnetic field intensity: after the target workpiece 7 is filled with magnetorheological fluid, the permanent magnet 41 is symmetrically arranged on the turntable 43 according to a pair of magnetic poles N-S by using the pressing plate 42 and the screws; the pair of permanent magnets 41 of each layer are arranged in a continuous rotation mode of 45 degrees, so that continuous spiral line movement of abrasive particles in the magnetorheological fluid is realized, and polishing efficiency and quality are improved; in addition, the position of the permanent magnet 41 on the groove of the turntable 43 is adjusted to change the magnetic field intensity on the inner wall of the target workpiece 7, so as to change the viscosity of the magnetorheological fluid, and ensure that the smooth movement of the flexible polishing film cannot be influenced because the viscosity cannot be too large; in addition, aiming at the pipe wall after reducing, the positions of the permanent magnets 41 of the corresponding layers are adjusted to enable the magnetic field of the target workpiece 7 in the vertical direction to have gradient change so as to realize uniform polishing of the inner wall of the reducing inner hole;

Step S5, polishing: starting a controller in the magnetic field driving system 5, simultaneously enabling the target workpiece 7 to do axial reciprocating motion and magnetic field rotation, increasing the processed length of the target workpiece 7 and realizing spiral line motion of abrasive particles in magnetorheological fluid, and then adjusting the reciprocating stroke, the reciprocating speed, the rotating speed and the running time by using the controller to effectively control the polishing quality of the inner wall;

step S6, cleaning an inner hole of the target workpiece 7: firstly, the permanent magnet 41 is removed, then the liquid in the liquid container 63 is replaced, deionized water or alcohol can be used as the replaced liquid, deionized water or alcohol is input by the conveying pump 61 to thoroughly clean the polished inner hole, and the above operation step S6 is repeated until the inner hole is cleaned.

In the embodiment, the magnetorheological polishing method is suitable for polishing the thin-wall variable-diameter inner hole with the inner diameter smaller than 10mm and the length more than 10 mm.

In some embodiments, the polishing device may be simply modified into a horizontal structure, and the working manner thereof is as follows: the target workpiece 7 is stationary, and the multiple magnetic field generating device 4 rotates while reciprocating. The polishing length of the inner wall of the target workpiece 7 in this form can be further increased.

Compared with the prior art, the embodiment of the invention discloses the following beneficial effects:

1. In the invention, the self-prepared magnetorheological fluid and the multi-magnetic-field generating device 4 are applied, so that the magnetorheological fluid can rotate and smoothly flow in the small pipe; the multi-magnetic field generating device 4 changes the magnetic field intensity on the inner wall of the target workpiece 7, can generate magnetic fields which are approximately uniformly distributed, can realize gradient change of the magnetic fields in the vertical direction, and is further suitable for polishing slender thin-wall through holes with the inner diameter smaller than 10mm and reducing capillaries.

2. In the invention, each pair of magnetic poles of the multi-magnetic field generating device 4 is equivalent to an auxiliary support, which is beneficial to realizing the transverse stress balance of the target workpiece 7 and solves the difficult problems of easy deformation and jumping in the processing process due to low self-rigidity of the capillary tube;

3. the invention is suitable for polishing the inner hole of the capillary-like part made of non-ferromagnetic materials, and the multi-magnetic field design can obtain uniform and better surface quality while improving the polishing efficiency; by adopting the vertical structure, the uneven quality of the processing surface of the horizontal structure caused by the difficulty in rotating the target workpiece 7 which circularly inputs the magnetorheological fluid can be avoided.

4. The invention has novel structural design, is easy to operate and change, can be changed into a horizontal structure through simple transformation, and has a working mode that the working mode is changed into that the target workpiece 7 is rotated and reciprocated by the static multi-magnetic field generating device 4, and the polishing length of the inner wall of the target workpiece 7 can be further increased in the mode.

The present invention is not limited to the conventional technical means known to those skilled in the art.

In the description of the present invention, it should be understood that the terms "longitudinal," "transverse," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate or are based on the orientation or positional relationship shown in the drawings, merely to facilitate description of the present invention, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present invention.

The above embodiments are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the claims of the present invention without departing from the design spirit of the present invention.

Claims (10)

1. A magnetorheological polishing device for a small-tube variable-diameter large-length-diameter-ratio inner hole, which is characterized by comprising:

the device comprises a device body (1) provided with a plurality of work tables with different horizontal heights, wherein a center hole with a coaxial center is formed in the center of each work table;

The reciprocating mechanism (2) comprises a guide rail (22) vertically fixedly connected to the device body (1), a sliding block (23) sliding on the guide rail (22), a ball screw (21) driving the sliding block (23) to reciprocate, a coupler (24) and a servo motor (25);

The clamping assembly (3) is fixedly connected to the sliding block (23) and provided with an ER chuck (32) which is coaxially arranged with the central hole, and the ER chuck (32) is used for clamping a target workpiece (7);

the multi-magnetic-field generating device (4) is rotationally connected between the two work tables and is provided with a magnetic field channel for accommodating a target workpiece (7) to pass through, the magnetic field channel and the central hole are coaxial, the magnetic field channel is externally arranged on a plurality of layers of turntables (43), and a pair of permanent magnets (41) are fixedly connected on each turntable (43);

The magnetic field driving system (5) is in transmission connection with the multi-magnetic field generating device (4) and controls the rotation of the magnetic field;

And the magnetorheological polishing solution supply circulation system (6) is connected with the target workpiece (7) and is used for circularly supplying the magnetorheological solution to the inner hole of the target workpiece (7).

2. Magnetorheological polishing device for small-tube variable-diameter large-length-diameter-ratio inner holes according to claim 1, characterized in that the multi-magnetic-field generating device (4) comprises a pressing plate (42), a connecting rod (44), a connecting shaft (45), a tapered roller bearing (46), the turntable (43) and the permanent magnet (41), wherein the turntable (43) is connected through the connecting rod (44) to form a multilayer structure, the multilayer structure is arranged in the central holes of the two working tables through the upper connecting shaft (45) and the lower connecting shaft (46), and the permanent magnet (41) is arranged on the turntable (43) through the pressing plate (42) and a screw.

3. Magnetorheological polishing device for small-tube variable-diameter large-length-diameter-ratio inner holes according to claim 2, characterized in that the number of layers of the turntable (43) is determined according to the length to be processed of the target workpiece (7), the rod length of the connecting rod (44) and the reciprocating stroke of the target workpiece (7), and the relationship is as follows: c= (L-T)/l+1, where C is the number of layers, L is the length to be processed of the target workpiece (7), T is the reciprocating stroke of the target workpiece (7), and L is the rod length of the connecting rod (44).

4. Magnetorheological polishing device for small-tube variable-diameter large-length-diameter-ratio inner holes according to claim 2, characterized in that the permanent magnets (41) are symmetrically arranged on the turntable (43) according to a pair of N-S or S-N magnetic poles, each pair of magnetic poles being arranged in a manner of continuously rotating 45 degrees.

5. Magnetorheological polishing device for small-tube variable-diameter large-length-diameter-ratio inner holes according to claim 4, characterized in that when the outer diameter of the target workpiece (7) is less than 5mm, a pair of magnetic poles are arranged on each turntable (43); when the outer diameter of the target workpiece (7) is between 5 and 10mm, two pairs of magnetic poles are arranged on each turntable (43) and are symmetrically arranged.

6. Magnetorheological finishing device for small-tube variable-diameter large-length-diameter-ratio inner holes according to claim 4 or 5, characterized in that the permanent magnet (41) is an N35 permanent magnet (41) as a magnetic field source.

7. Magnetorheological finishing device for small-tube variable-diameter large-length-diameter-ratio inner holes according to claim 2, characterized in that the magnetic field strength can be adjusted in the range of 0-0.45T by adjusting the installation position of the permanent magnet (41).

8. Magnetorheological polishing device for small-tube variable-diameter large-length-diameter-ratio inner holes according to claim 1, characterized in that the rotating speed range of the magnetic field driving system (5) for driving the multi-magnetic-field generating device (4) to rotate is 0-1000 rpm, and the radial and axial circular runout of the turntable (43) in the multi-magnetic-field generating device (4) is within 0.01 mm.

9. A magnetorheological polishing method for a small-tube variable-diameter large-length-diameter-ratio inner hole, characterized by applying the magnetorheological polishing device for a small-tube variable-diameter large-length-diameter-ratio inner hole according to any one of claims 1 to 8, comprising the following steps:

s1, preparing magnetorheological fluid;

S2, installing a target workpiece (7);

step S3, setting a liquid loop;

s4, distributing magnetic fields and adjusting the magnetic field intensity;

S5, polishing;

And S6, cleaning an inner hole of the target workpiece (7).

10. The magnetorheological polishing method for the inner bore with the small pipe variable diameter and large length-diameter ratio according to claim 9, wherein in the step S1, the magnetorheological fluid is prepared according to 36 percent by volume of hydroxyl iron powder, 6 percent by volume of silicon carbide abrasive particles or diamond abrasive particles, 57 percent by volume of aqueous liquid and the balance of stabilizer.