JP2619740B2 - Magnetic polishing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for rotating a circular inner surface of a workpiece such as a pipe in a space defined by the inner surface by rotating a polishing tool disposed in the space. And a magnetic polishing apparatus for polishing.

[0002]

2. Description of the Related Art An apparatus for polishing the surface of a workpiece using magnetic abrasive grains and a rotating magnetic field is described in Japanese Patent Application Laid-Open No. 62-102969. However, in this apparatus, since the magnetic abrasive grains themselves are used as a tool and are moved by a rotating magnetic field, the polishing efficiency is poor.

[0003] A polishing tool is arranged in a workpiece having a circular inner surface, that is, a surface to be polished, and the tool is rotated in the workpiece by a magnetic field rotating around the axis of the workpiece.
An inner surface magnetic polishing apparatus for polishing the surface to be polished thereby is described in Journal of Precision Engineering, Vol. 55, No. 10, pp. 148-153.

In this known inner surface magnetic polishing apparatus, a workpiece is supported so as to extend substantially in a horizontal direction.
The tool is rotated about the axis of the workpiece in contact with the surface to be polished. During polishing, the workpiece or tool is relatively moved at least once in the axial direction of the workpiece.
Thus, the polished surface is polished by rotation of the tool about the axis of the workpiece.

However, in the known internal magnetic polishing apparatus, the tool is rotated within the workpiece and the workpiece or the tool is moved only in the axial direction of the workpiece. When polishing is performed using a processing liquid, the abrasive grains are not uniformly distributed on the inner surface of the workpiece, so that the surface to be polished cannot be uniformly polished and the polishing efficiency is low.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an inner surface magnetic polishing apparatus capable of uniformly and efficiently polishing a surface to be polished using a working liquid.

[0007]

A polishing apparatus according to the present invention is a state in which a magnetic tool having a polishing action disposed in a space defined by a circular inner surface of a non-magnetic workpiece is brought into contact with the inner surface. Magnetic field generating means for generating a magnetic field that rotates around the axis of the workpiece; and causing relative reciprocating motion of the workpiece in the axial direction between the workpiece and the tool. And a drive unit for rotating the workpiece around its axis, and a unit for supplying a liquid containing abrasive grains into the space.

The liquid containing the abrasive grains, ie, the working liquid, is supplied into the space of the workpiece prior to or during the polishing.

If the workpiece is not rotated at the time of polishing, only the machining fluid attached to the tool is attached to the inner surface to be polished, that is, the upper portion of the polished surface with the rotation of the tool. The amount of liquid adhering to each part in the circumferential direction of the polished surface is not uniform.

However, when the workpiece is rotated at such a speed that the processing fluid is not rotated together with the workpiece, the processing fluid in the workpiece collects at the bottom of the space by its own weight, and the processing fluid is removed from the surface to be polished. It adheres uniformly over the entire circumferential direction.

Since the working fluid in the space is moved in the axial direction of the workpiece along the relative reciprocating motion between the workpiece and the tool, the working fluid in the axial direction of the surface to be polished is also moved. Adheres uniformly throughout.

During polishing, the workpiece and the tool are reciprocated relatively in the axial direction of the workpiece while the tool is rotated around the axis of the workpiece. In between, relative movement occurs such that the tool follows a spiral trajectory on the surface to be polished. The trajectory of the tool when the workpiece or the tool is moved to one side in the axial direction of the workpiece and the trajectory of the tool when the workpiece or the tool is moved to the other,
Cross each other.

According to the present invention, while the tool is rotated by the magnetic field, the workpiece is rotated about its axis and the workpiece and the tool are reciprocated relatively and reciprocally in the axial direction of the workpiece. Since the driving means is provided, the processing liquid supplied into the space of the workpiece adheres uniformly over the entire surface to be polished, and as a result, the abrasive grains are uniformly distributed. Therefore, the surface to be polished can be uniformly polished.

According to the present invention, the locus of the tool on the surface to be polished when the workpiece or the tool is moved to one side in the axial direction of the workpiece and the surface to be polished when the workpiece or the tool is moved to the other side Since the trajectory of the tool above intersects,
The polishing distance per unit time is increased in combination with the fact that the processing liquid is uniformly attached to the entire surface to be polished, and the cutting effect of the individual abrasive grains due to the intersection of the polishing trajectories is increased, thereby significantly improving the polishing efficiency.

The driving means is provided with a slider arranged to be movable in the axial direction of the workpiece with respect to the magnetic field generating means, and supported by the slider so as to be rotatable around the axis. A chuck for gripping, a moving mechanism for moving the slider in the axial direction of the workpiece, and a rotating mechanism for rotating the chuck about the axis may be provided. In this case, the relative reciprocating motion between the workpiece and the tool is caused by moving the workpiece with respect to the magnetic field generating means.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, a magnetic polishing apparatus 10 includes a box-shaped frame 12 housing a power supply for the magnetic polishing apparatus. Frame 12
By utilizing the plurality of casters 14 attached to the lower surface, the floor can be moved to an arbitrary position on the floor and releasably installed at that position.

A magnetic field generator 16 for generating a rotating magnetic field is mounted on the frame 12.

As shown in FIGS. 1 and 2, the magnetic field generator 16 includes an annular yoke 18 made of a magnetic material,
A plurality (six in the example shown) arranged at equal angular intervals in 8
, And is attached to the frame 12 by a plurality of brackets 22 so that the center axis of the yoke 18 extends substantially in the horizontal direction.

Each electromagnet 20 is formed by winding a coil 26 around an iron core 24. Each iron core is attached to the yoke 18 by a connector 28 so as to extend in the radial direction of the yoke 18, and is magnetically connected to the yoke 18.

The tip end face, ie, the pole face, of the iron core 24 jointly defines a space for receiving the workpiece 30 inside thereof. The workpiece 30 has a circular inner surface, that is, a polished surface like a pipe, and is made of a non-magnetic material such as stainless steel.

On the frame 12, a drive mechanism 32 for gripping the long workpiece 30, moving the workpiece in the axial direction thereof, and rotating the workpiece about the axis is also provided. Are located.

The drive mechanism 32 includes a slider 34 movable in a direction parallel to the center axis of the yoke 18, as shown in FIGS. The slider 34 is supported on a rail assembly 36 fixed to the frame 12.

In the illustrated example, the rail assembly 36 supports a pair of rails 38 extending parallel to each other and to the center axis of the yoke 18 on a pair of brackets 40 fixed to the frame 12. The rail 3
8 support.

The chuck 42 for gripping the workpiece 30 includes
It is arranged on a pair of support members 44 extending upward from the slider 34 in parallel with each other, and is rotatable about the axis of the workpiece 30 by bearings 46 (see FIG. 5) attached to the support members 44. Supported.

As shown in FIGS. 3 and 4, the workpiece 3
A moving mechanism 50 for moving the rotation axis 0 in the axial direction includes a rotation source 52 having an electric motor and a speed reducer, a cam disk 54 attached to the rotation shaft, and the rotational movement of the cam disk 54, which is the axis of the workpiece. And a crankshaft 56 for converting the reciprocating motion in the direction.

One end of the crankshaft 56 is connected to the outer peripheral edge of the cam disk 52, and the other end is connected to the slider 34 via a bracket 58. For this reason, the slider 34 is reciprocated in the axial direction of the workpiece 30 by the rotation of the rotation source 52, whereby the chuck 4 is moved.
2 is also reciprocated in the same direction.

As shown in FIGS. 3 and 5, the workpiece 3
A rotation mechanism 60 for rotating the rotation axis 0 around its axis includes a rotation source 62 having an electric motor and a reduction gear, a pulley 64 attached to the rotation axis, and a pulley 66 attached to the outer peripheral surface of the chuck 42. And an endless belt 68 wound around pulleys 64 and 66.
Rotates the chuck 42 around the axis of the workpiece 30.

As shown in FIG. 1, prior to polishing, the workpiece 30 extends through the chuck 42 and the space defined by the pole faces of the iron core 24 and is slightly inclined with respect to the horizontal. Then, it is gripped by the chuck 42.

Next, the polishing tool 70 is placed in the workpiece 30 and a predetermined amount of working fluid is supplied into the workpiece 30 by the injector 72 from one end in the longitudinal direction.

The tool 70 includes a magnetic material or a permanent magnet material. When the tool 70 includes a permanent magnet material, the permanent magnet material is magnetized, and the tool 70 acts as a permanent magnet.

The shape of the tool 70 is arbitrary, such as a triangular prism, but can be, for example, a rectangular parallelepiped as shown in FIG. The tool 70 shown in FIG. 6 has four portions 74, 74, 76, 76 which are formed as arc surfaces.
4 or 76, 76 are arranged so as to contact the inner surface of the workpiece 30.

It is preferable that the injector 72 includes an adjusting device such as a valve for adjusting the supply amount of the processing liquid. A slurry containing abrasive grains can be used as the working liquid.

The workpiece 30 is supported such that the height of the part on the side where the injector 72 is disposed is slightly higher than the height of the part on the opposite side. For this reason, the working fluid moves in the workpiece 30 with the passage of time.

At the time of polishing, a three-phase alternating current is supplied to each coil 26 of the electromagnet 20 to generate a rotating magnetic field from the pole face of the iron core 24. The connection method between the coil 26 and the three-phase AC power supply is described in, for example, JP-A-62-102969.

As a result, a rotating magnetic field is generated by changing the polarity of the electromagnet 20, and the tool 70 arranged in the workpiece 30 comes into contact with the inner surface of the workpiece 30 with the movement of the rotating magnetic field. In this state, it is rotated in the circumferential direction along the inner surface. The rotation speed of the tool 70 can be changed by changing the frequency of the alternating current supplied to the electromagnet.

During the polishing, the slider 34 is reciprocated by the moving mechanism 50 at a frequency lower than the rotation frequency of the tool 70. Thereby, the workpiece 30 is reciprocated in the axial direction.

However, the tool 70 disposed in the workpiece 30 is not displaced in the axial direction of the workpiece 30 with respect to the electromagnet 20 because of the magnetic flux generated by the electromagnet 20. Therefore, a relative movement of the workpiece 30 in the axial direction occurs between the workpiece 30 and the tool 70.

During polishing, the chuck 42 is also rotated by the rotation mechanism 60 about the axis of the workpiece 30 at a frequency lower than the rotation frequency of the tool 70. Thereby, the workpiece 30 is rotated around its axis. The rotation frequency of the workpiece is such that the inner working fluid is
It is a value that is not rotated with.

The rotational frequency of the tool 70, the reciprocating motion frequency of the workpiece 30, and the rotational frequency of the workpiece 30 can be, for example, about 30 to 50 Hz, 1 to 2 Hz, and 0.1 to 1 Hz, respectively. .

The direction of rotation of the workpiece 30 may be the same as the direction of rotation of the tool, or may be reversed. Also,
The rotation and reciprocation of the workpiece 30 may be continuous or intermittent.

The working fluid in the workpiece 30 is
Is rotated, it gathers at the bottom of the polished surface due to its own weight, and adheres to the entire surface of the polished surface in the circumferential direction as the workpiece 30 rotates. Also, the working fluid in the workpiece 30 is
Due to the relative reciprocation of the workpiece 30 and the tool 70 and the fact that the workpiece 30 is inclined with respect to the horizontal line, the workpiece 30 is moved in the longitudinal direction. As a result, the processing liquid in the workpiece 30 adheres uniformly over the entire polished surface.

Due to the rotation of the tool 70 and the reciprocating motion of the workpiece 30, the relative movement between the workpiece 30 and the tool 70 is such that the tool 70 draws a spiral path on the surface to be polished. Movement occurs. The trajectory of the tool when the workpiece 30 is moved to one side in the axial direction and the trajectory of the tool when the workpiece 30 is moved to the other side cross each other.

During the polishing, it is preferable to supply the working liquid to the workpiece 30 continuously or intermittently. Further, it is preferable to arrange a chute and a container for receiving the machining fluid flowing out of the workpiece on the side opposite to the injector 72 side.

When the polishing of the workpiece 30 within the range of the stroke by the moving mechanism 50 is completed, the gripping position of the workpiece 30 on the chuck 42 is changed, and the polishing within the following range is performed.

The range of the reciprocating movement of the workpiece 30 can be adjusted, for example, by allowing the position at which the crankshaft 56 is attached to the cam disk 54 to be changed.

According to the magnetic polishing apparatus 10, the workpiece 30
Due to the rotation of the workpiece and the reciprocating movement of the workpiece 30, the processing liquid in the workpiece 30 uniformly adheres to the entire polished surface. In addition, the tool 7 when the workpiece 30 is moved in one direction
Since the trajectory of 0 and the trajectory of the tool 70 at the time of moving to the other cross, the polishing efficiency is remarkably improved in combination with the fact that the working liquid uniformly adheres to the entire surface to be polished.

Although one magnetic field generator 16 is used in the illustrated example, a plurality of magnetic field generators 16 may be sequentially arranged on the workpiece in the axial direction. In this case, the tool 70 may be arranged for each magnetic field generator, or one tool may be rotated jointly by a plurality of magnetic field generators.

[Brief description of the drawings]

FIG. 1 is a front view showing an embodiment of a magnetic polishing apparatus according to the present invention.

FIG. 2 is an enlarged view showing one embodiment of a magnetic field generator.

FIG. 3 is a perspective view showing one embodiment of a driving mechanism.

FIG. 4 is a perspective view showing one embodiment of a moving mechanism.

FIG. 5 is a perspective view showing one embodiment of a rotation mechanism.

FIG. 6 is a perspective view showing one embodiment of a polishing tool.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Magnetic polishing apparatus 12 Frame 16 Magnetic field generator 18 Yoke 20 Electromagnet 30 Workpiece 32 Drive mechanism 34 Slider 36 Rail assembly 42 Chuck 50 Moving mechanism 60 Rotary mechanism 70 Polishing tool 72 Injector of working fluid

Claims (2)

(57) [Claims] 1. A magnetic polishing apparatus for polishing a circular inner surface of a non-magnetic workpiece, wherein a magnetic tool having a polishing action arranged in a space defined by the inner surface is brought into contact with the inner surface. Magnetic field generating means for generating a magnetic field that rotates around the axis of the work piece, and rotating the work piece around the axis while the work piece and the tool are between the work piece and the tool. A magnetic polishing apparatus, comprising: driving means for repeatedly causing a relative reciprocating motion of a workpiece in an axial direction; and means for supplying a liquid containing abrasive grains into the space. 2. The driving device according to claim 1, wherein the driving unit is supported by a frame so as to be movable in an axial direction of the workpiece, and is supported by the slider so as to be rotatable around the axis, and holds the workpiece. 2. The magnetic polishing apparatus according to claim 1, further comprising: a chuck that moves the slider in an axial direction of the workpiece; and a rotation mechanism that rotates the chuck around the axis. 3.