JPH05337813A - Method of polishing inner surface of nonmagnetic pipe and device therefor - Google Patents

Abstract

PURPOSE:To widely control internal surface polishing conditions for a nonmagnetic pipe, and aim at enhancing the polishing efficiency and at maintaining the polishing characteristic. CONSTITUTION:Guide holes 21 are formed in a rotary ring 21 adapted to be rotated around a nonmagnetic pipe 1, and a magnet 23B is attached to the rotary ring 21. The nonmagnetic pipe 1 is rotated by a chuck 32 which is rotated by a motor 35 through the intermediary of a rotary cylinder 32 and a gripping cylinder 31, And a movable base 30 is reciprocated by link mechanisms 45, 46. The gripping cylinder 31 is attached to the rotary cylinder 33, slidably in the axial direction, through spline-joint, and is superposed thereto with high frequency vibration by a piezoelectric vibrator 39. A polishing pressure and a polishing peripheral speed can be set independent from each other due to the combination of the rotational speed of the rotary ring 21 and the rotational speed of the nonmagnetic pipe 1, and further, the superposition of the high frequency vibration enhances the polishing efficiency so as to maintain the polishing characteristic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for polishing the inner surface of a non-magnetic tube, and more particularly to a technique for optimizing polishing conditions and improving polishing efficiency according to the material and diameter of the non-magnetic tube.

[0002]

2. Description of the Related Art As a conventional method for polishing a non-magnetic tube, there has been a method in which a polishing tool made of a magnetic material is housed in the tube and a magnetic field is applied from the outside to rotate the magnetic material. In this case, the magnetic body is rotated by the rotation of the magnet or the rotating magnetic field generated by the electromagnetic coil. The advantage of these polishing methods is that the mechanism can be polished without contact with the drive mechanism by magnetic action, the mechanism is simple and easy to adjust, and only a specific portion in the tube can be polished.

[0003]

By the way, there are some non-magnetic tubes made of various alloys such as stainless steel, aluminum and brass depending on the application, and in recent years, many of them have a small tube diameter. It is becoming more and more necessary to optimize polishing conditions according to these various materials and tube diameters. Further, in recent years, the demands on the inner surface of the pipe have become stricter year by year, and it is desired to perform the processing efficiently under the optimum conditions from the rough polishing to the final finishing. Furthermore, even with partial polishing, which is an advantage of magnetic polishing, there is a need for a method capable of processing only fine regions with higher efficiency than in the past. Therefore, in view of the above problems, the present invention provides a magnetic polishing method and apparatus capable of easily optimizing the polishing conditions according to the material and diameter of the tube and enhancing the polishing efficiency, and capable of high quality inner surface treatment. The purpose is to get.

[0004]

Means for Solving the Problems The means taken by the present invention to achieve the above object is to rotate a magnetic field around the axis of a non-magnetic tube and rotate the non-magnetic tube around its axis to polish the magnetic field. is there. In addition, the magnetic field is rotated about the axis of the non-magnetic tube relative to the non-magnetic tube, and is reciprocated relatively in the axial direction, and high-frequency vibration with a smaller amplitude and higher frequency than the reciprocating motion is applied to the axis of the tube. It is to be superposed in the direction and polished.

[0005]

According to such means, since the non-magnetic tube itself rotates when the magnetic field in the tube is driven by rotating the magnetic field, the non-magnetic tube of magnetic material determined by the sum of the rotation speed and the rotation speed. It is possible to independently set the peripheral speed with respect to and the centrifugal force applied to the magnetic body, which is determined only by the rotation speed. As a means for realizing the rotation of the magnetic field, when a magnet is attached to a rotating ring having a plurality of guide diameter portions radially arranged so as to be movable along the guide diameter portions, various magnetism can be obtained with a simple structure. It can be used for body and pipe material and pipe diameter. When high-frequency vibration is superimposed on the axial reciprocating motion, the polishing conditions can be changed, the momentum of the magnetic body increases, and when the magnetic body is liquid or powder, the high-frequency vibration propagates inside the magnetic body. .

[0006]

Embodiments of the present invention will now be described with reference to the drawings. This embodiment is an example of a polishing apparatus for realizing the polishing method and apparatus according to the present invention. As shown in FIG. 1, a magnetic field forming unit 2 for forming a rotating magnetic field on a base 10 and a non-magnetic tube. A rotation drive unit 3 for gripping and rotating 1 and an axial drive unit 4 for driving the non-magnetic tube 1 in its axial direction are provided.

The magnetic field forming unit 2 has a disk-shaped rotating ring 21.
Is rotatably attached, and the belt 2 is driven by the drive motor 26 with the non-magnetic tube 1 passing through the center hole 21b.
5, rotated via the pulley 24. As shown in FIG. 2, guide holes 21a extending in the radial direction are radially formed in the rotating ring 21 at intervals of 22.5 degrees. A fixture 22 is attached by a bolt at an arbitrary position in the radial direction of the guide hole 21a, and the magnet 2 is attached to this fixture.
3A and 23B are fixed by bolts. 2 in the illustrated example
The two magnets 23A and 23B are attached at opposing positions (at intervals of 180 degrees) so that their opposite poles face inward. This magnet has a shell-like shape with a slightly narrowed tip and a smooth surface without ridges in order to make the magnetic flux distribution uniform and increase the magnetic flux density in the tube.

It is desirable that the arrangement of the magnets 23A and 23B be changed depending on the tube diameter of the non-magnetic tube 1 and the type of magnetic material housed inside. It is natural to move the position of the magnet in the radial direction depending on the pipe diameter, but in the case where a magnetic tool extended in the rotational direction is housed in the pipe, in order to obtain sufficient synchronous torque, the rotational direction of the polishing tool It is necessary to match the magnetic pole length with the magnetic pole spacing, and it is necessary to change the mutual angle of the magnets. Further, according to the experiments by the inventor, even when the abrasive particles are mixed and used in the magnetic powder or the magnetic fluid, the optimum angular interval of the magnets changes depending on the tube diameter. It has been confirmed that 120 to 180 degrees is optimal in terms of driving efficiency as the tube diameter decreases to about 90 degrees. Depending on the conditions, three or more magnets may be arranged. Although the guide hole 21a is provided in the rotary ring, any structure such as a rib or a slide shaft can be selected as long as it can guide the magnet so as to be movable in the radial direction. The means for rotating the magnetic field according to the present invention is not limited to the above method, and a rotating magnetic field generated by an electromagnetic coil may be used.

The rotary drive unit 3 has a grip cylinder 31 having a three-jaw interlocking chuck 32 for gripping the non-magnetic tube 1, a rotary cylinder 33 splined to the grip cylinder 31, and a rotary cylinder 33 as a gear. A motor 35 driven via 34, a vibration plate 37 that engages with an engagement portion 36 of the grip cylinder 31, and a vibration plate 37.
The piezoelectric vibrator 39 having the shaft center part 38 fitted to the output part as an output part. The piezoelectric vibrator 39 is connected to a variable frequency function generator or the like to cause the shaft center portion 38 to project and retract at an arbitrary frequency, and applies high frequency vibration in the axial direction to the non-magnetic tube 1 via the vibration plate 37 and the grip cylinder 31. . Of course, other means such as an air vibrator may be used depending on the required amplitude and frequency. The rotary drive unit 3 is housed in the movable unit 30 so that the entire rotary drive unit 3 can move along the slide shaft 42. The axial drive section 4 includes a movable base 41 having a slide shaft 42 slidably supporting the movable section 30, a link mechanism including links 45 and 46 for reciprocating the movable section 30 and a motor 47, and a movable base. It is composed of a ball screw 43 for moving 41 in the axial direction and a motor 44, and can move forward the movable portion 30 holding the non-magnetic tube 1 while reciprocating in the axial direction at a predetermined amplitude and cycle. The movable bearing 11 is composed of three parts that can move in the radial direction of the non-magnetic tube 1, and can support non-magnetic tubes having different diameters.

The magnetic material used in this apparatus is a polishing tool consisting of an extended magnetic material or magnet that matches the curvature of the inner surface of the tube, a magnetic fluid mixed with abrasive particles such as diamond particles, or magnetic powder. Or a mixture of these with abrasive grains. The extended magnetic body or magnet has a large synchronizing force with respect to the rotating magnetic field and has a high polishing efficiency.
On the other hand, magnetic fluids or powders that are not in the extended shape cause slippage and have a small synchronizing force, which makes them suitable for finishing processes. In view of this, the present inventor uses the above-mentioned polishing tool or the extended shape (needle-shaped) magnetic powder in rough polishing to efficiently perform the polishing, and uses a general magnetic fluid or powder in the final step. Therefore, both the polishing efficiency and the quality of the polished surface are compatible.

In the present embodiment, the rotation of the rotary ring 21 drives the magnetic tools and magnetic particles contained in the non-magnetic tube 1 to rotate. At the same time, the rotary drive unit 3 drives the non-magnetic tube 1 to rotate.
It can rotate itself. The peripheral speed of the tool or fluid with respect to the non-magnetic tube 1 is determined by the sum of both rotation amounts, but the centrifugal force due to the rotation of the tool or fluid is determined only by the rotating magnetic field of the rotating ring 21. Therefore, the peripheral speed and the centrifugal force of the polishing member can be set independently by adjusting the rotation speeds of both. For example, if the rotation of the rotary ring 21 and the rotation of the non-magnetic tube 1 are reversed, the peripheral speed of the tool or abrasive grains can be increased while suppressing the centrifugal force.
When both are rotated in the same direction, the centrifugal force can be increased while suppressing the peripheral speed. Since this centrifugal force affects the polishing pressure, the polishing conditions can be adjusted over a wider range than in the past. Further, when a magnetic fluid (powder) is used, the fluid (powder) spreads in the axial direction of the tube due to the centrifugal force, but as described above, the centrifugal force can be set independently of the peripheral speed in this embodiment. Therefore, the spreading range of the fluid can also be adjusted, and for example, only a narrow area in the pipe such as a welded portion can be polished without affecting other portions.

In the polishing by the above apparatus, the rotational movement of the tool or fluid (powder) by the magnetic field forming unit 2 and the rotation driving unit 3 and the reciprocating movement by the link mechanism cause the polishing cloth and the abrasive grains to spiral in the tube. Optimum value is searched for by changing the crossing angle of the spiral orbit (the angle between the circumference of the tube and the path of the polishing member), which is usually determined by the peripheral speed of rotation, the amplitude of reciprocating motion, and the cycle, depending on the material of the tube. The polishing conditions can be optimized.
In this device, since the piezoelectric vibrator 39 that superimposes high-frequency vibrations is further provided on the rotation drive unit 3, the surface roughness and smoothness of the inner surface of the pipe are achieved in a high degree, like the combination of the rotation, rotation and reciprocation. The degree of freedom in setting the conditions for improving the polishing conditions can be increased, and the polishing conditions can be set in a wide range, and the momentum of the tool and the abrasive grains can be increased without increasing the rotation speed and the reciprocating motion, so that the polishing efficiency can be improved. Especially when using magnetic fluid or magnetic powder or abrasive particles mixed in these, this high-frequency vibration disperses polishing debris mixed in these fluids or powder, or separates abrasive debris from the abrasive particles. It has the effect of causing the above-mentioned effects, and the initial polishing efficiency and polishing characteristics can be maintained for a long time. Note that the amplitude and frequency of high-frequency vibration depend on the material of the tube, the type of magnetic material,
It should be set appropriately according to the rotation and rotation speeds, the amplitude and cycle of reciprocating motion, etc., but the amplitude should be of the order of microns and the frequency should be high enough to ignore the rotational direction component of the displacement vector due to vibration. Is desirable.

The polishing method according to the present invention can be applied not only to the straight pipe shown in the embodiment but also to a different diameter pipe (reducer) having a different diameter, and also to a curved pipe. Further, the reciprocation of the device is not limited to the case of driving the non-magnetic tube, and the magnetic field forming means, that is, the rotating ring may be reciprocated.
Further, since it is sufficient for the high frequency vibration to be applied between the rotating magnetic field and the non-magnetic tube, it may be applied to the magnetic field forming means side.

[0014]

As described above, according to the present invention, the means for rotating the magnetic field and the means for rotating the non-magnetic tube are used together or provided side by side, and high frequency vibration is superimposed on the reciprocating motion between the magnetic field and the non-magnetic tube. Since it is characterized in that it is provided with a means for causing or superimposing it, the following effects are achieved. By rotating the magnetic field and rotating the non-magnetic tube, the peripheral speed of the polishing tool and abrasive grains with respect to the inner surface of the non-magnetic tube and the centrifugal force of the polishing tool and abrasive grains can be set independently, so the centrifugal force can be set independently. With this, the polishing pressure and the spread of the magnetic fluid or powder in the axial direction can be controlled, and the polishing conditions can be adjusted in a wide range. When high frequency vibration is applied to the reciprocating motion of the non-magnetic tube in the axial direction, the polishing conditions can be easily adjusted, and the momentum of the magnetic material is increased to improve the polishing efficiency. When a magnetic fluid or powder is used, high-frequency vibration promotes dispersion of polishing debris and separation of polishing debris from abrasive grains, and polishing efficiency and polishing characteristics can be maintained for a long time.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the configuration of an inner surface polishing apparatus for a non-magnetic tube according to the present invention.

FIG. 2 is a front view showing the structure of a rotary ring of the same device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Non-magnetic tube 2 Magnetic field forming part 21 Rotating ring 21a Guide hole 23A, 23B Magnet 3 Rotation drive part 31 Grasping cylinder 33 Rotation cylinder 39 Piezoelectric vibrator 4 Axial direction drive part

Claims (6)

[Claims] 1. A method for driving a magnetic substance in a non-magnetic tube by a magnetic field applied from the outside of the non-magnetic tube to polish the inner surface of the non-magnetic tube, wherein the magnetic field is rotated around an axis of the non-magnetic tube and the non-magnetic tube is rotated. A method for polishing the inner surface of a non-magnetic tube, which comprises rotating the magnet around an axis. 2. A method for polishing an inner surface of a non-magnetic tube by driving a magnetic material in the tube by a magnetic field applied from the outside of the non-magnetic tube, wherein the magnetic field is around the axis of the non-magnetic tube relative to the non-magnetic tube. The inner surface of the non-magnetic tube is polished while being relatively reciprocated in the axial direction of the non-magnetic tube, and high-frequency vibration having a smaller amplitude and a higher frequency than the reciprocating movement is superimposed in the axial direction. Method. 3. The method for polishing an inner surface of a non-magnetic tube according to claim 1, wherein the magnetic material is magnetic fluid or magnetic powder. 4. An apparatus for polishing a inner surface of a non-magnetic tube by driving a magnetic material in the non-magnetic tube by a magnetic field applied from the outside of the non-magnetic tube. An inner surface polishing apparatus for a non-magnetic tube, comprising: a magnetic field rotating means for forming a magnetic field; a rotation driving means for rotating the non-magnetic tube; and an axial direction driving means capable of moving the non-magnetic tube in an axial direction. 5. The rotating ring according to claim 4, wherein the magnetic field rotating means includes a rotating ring radially arranged with a plurality of guide diameter portions extending in a radial direction, the rotating ring being arranged in a state where the non-magnetic tube penetrates the center hole. An inner surface polishing apparatus for a non-magnetic tube, comprising a magnet mounted so as to be movable along a guide diameter portion of the ring. 6. An apparatus for polishing a inner surface of a non-magnetic tube by driving a magnetic material inside the tube by a magnetic field applied from the outside of the non-magnetic tube, wherein the magnetic field rotates relative to the non-magnetic tube about its axis. Magnetic field forming means for forming a magnetic field, an axial driving means capable of relatively reciprocating a non-magnetic tube in the axial direction with respect to the magnetic field, and a high frequency vibration having a small amplitude and a high frequency than the reciprocating motion. An inner surface polishing apparatus for a non-magnetic tube, comprising: a vibration applying unit that is superposed in the axial direction of the magnetic tube.