JPS60167761A - Surface polishing device - Google Patents

Abstract

PURPOSE:To improve a degree of roundness in a work ever so better, by setting up the work being pregnated in a working fluid mixing abrasive grains, in a magnetic fluid, while installing a magnetic field generator, which makes a work axial center a turning center, in the outside of a working fluid vessel and making it produce a swirl stream of the working fluid. CONSTITUTION:When a motor 50 is driven, each of magnets 58 and 42 at both upper and lower revolving magnet holding members 60 and 44 synchronously rotates together, producing a revolving magnetic field there, whereby a magnetic fluid is magnetized and draggingly turned round, causing a swirl stream in an arrow (b) direction around the work 70, therefore abrasive grains in a working fluid also moves in the same direction and uniformly collide with an outer circumference of the work 70, thus surface polishing takes place. Since these abrasive grains polish a surface of the work 70 while moving along the swirl stream that makes an axial center of the work 70 its turning center, this turning motion approximates to a state of roundness owing to fluidic inertia, thus a degree of roundness in the work 70 is improved.

Description

[Detailed Description of the Invention] [Technical Field] The present invention applies rIA to a surface polishing apparatus, and in particular, a workpiece is immersed in a machining fluid made of a magnetic fluid mixed with abrasive grains, and a rotating magnetic field is applied to the machining fluid. This invention relates to a surface polishing device that generates a swirling flow of machining fluid around a workpiece. The surface polishing apparatus of the present invention is effective when used for polishing the surface of a workpiece such as a cylindrical or round rod-shaped ceramic, glass, metal, or the like.

[Prior Art] Conventionally, as a surface polishing device for polishing a workpiece immersed in a machining fluid containing a magnetic fluid and abrasive grains, as shown in FIG. A double cylinder 12 consisting of an inner cylinder and an outer cylinder as shown in FIG. is rotatably supported by a rotating shaft 14, and an electromagnetic coil 16 and a container 18 for containing a machining fluid are provided in the double cylinder 12, and magnetic poles 19.
A radial static magnetic field is created between 20 and 20 to orient the magnetic fluid and abrasive grains in the machining fluid along this field, and the spindle 22 that clamps the workpiece 21 in the machining fluid can be rotated. As shown in the figure, a wrap 28 is separated by a certain gap G from the surface of the workpiece 26 in the machining liquid container 24.
It has been proposed to rotatably support the wrap 28 and provide a magnetic field between the wrap 28 and the iron core 32 using electromagnetic coils 29 and 30. This is the surface polishing apparatus disclosed in Japanese Patent Application Laid-Open No. 5'1-163057.

However, in the case shown in FIG. 1, the workpiece 4 is fixed;
In addition, since the moving direction of the abrasive grains is not uniform, the collision of the abrasive grains with the surface of the workpiece is partially biased, and as a result, it is difficult to improve the roundness of the workpiece having a circular cross section. In the system shown in Figure 2, the workpiece is rotated in the middle of a radial static magnetic field, and the machining fluid container is also rotated, so collisions and friction of the abrasive grains against the workpiece are uneven, and As a result, as mentioned above, it is difficult to improve the roundness of the workpiece, and the method shown in Fig. 3 is for polishing the flat part of the workpiece, and the surface of the workpiece with a circular cross section is polished. There was a problem in that it was difficult to use for polishing.

[Object of the Invention] The present invention was made against the background of the above, and an object of the present invention is to add abrasive grains to a magnetic fluid that can improve the roundness of a workpiece having a circular cross section. An object of the present invention is to provide a surface polishing device that uses a processing fluid containing a mixture of the following.

[Structure of the Invention] The gist of the present invention, which has been made to achieve the above object, is to place a workpiece in a container containing a machining fluid made of a magnetic fluid mixed with abrasive grains. In addition to providing a workpiece attachment part that can be mounted in an immersed state, a rotating magnetic field generating device for generating a rotating magnetic field with the workpiece axis as the center of rotation is provided outside the container. The structure is such that a swirling flow of machining fluid is generated around the swirling center. Here, the expression "the axis of the workpiece is the center of rotation or the center of rotation" does not mean that the center of rotation or the center of rotation completely coincides with the axis of the workpiece, but also includes cases where the center of rotation or the center of rotation is slightly deviated from the axis of the workpiece.

[Example] An example of the present invention will be described in detail below based on the drawings.

In FIG. 4, reference numeral 34 denotes a container made of a cylindrical non-magnetic material with an open top for containing the machining fluid, and at the center of the container is the upper end of a shaft-shaped support member 36 erected on a substrate 35. The sides are inserted and secured in a fluid-tight manner. Support member 36
The upper end portion can be fitted into a cylindrical workpiece inner hole, and constitutes a workpiece mounting portion. In addition, in the case of a round bar-shaped workpiece, the workpiece can be attached by providing a hole into which the end of the workpiece can be fitted. A lower rotating magnet holding member 44 that can rotatably support the magnet 42 in a cantilevered manner near the outside of the bottom surface of the container 34 is attached to the supporting member 36 . A timing belt 46 is attached to the holding member 44.
A pulley part 48 is provided for winding the motor, while the electric motor 15
0 via a coupling 52 to the Ic drive shaft 54.
A timing pulley 56 is fixed to the holding member 44, and a belt 46 is hung thereon so that the holding member 44 can be rotated.

Above the container 34, there is an upper rotating magnet holding member 60 having the same structure as the holding member 44, which can rotatably support the magnet 5B near the upper surface of the machining liquid in a cantilevered manner.
A timing pulley 66 fixed to a pulley portion 64 and a drive shaft 54 is connected via a timing belt 68, and the holding member 60 can be rotationally driven. ing. Each magnet 42.58 has different magnetic poles located opposite each other,
and timing pulleys 56 and 66 and pulley parts 48 and 6
4 means that the number of teeth is the same, and both magnets are 42.58.
are configured so that they can be rotationally driven in the same direction and at the same speed synchronously. In addition, in place of the timing belt and pulley,
The holding members 44 and 60 may be rotated at the same time by using gears. Both holding members 44 and 60 configured as described above constitute a rotating magnetic field generating device that generates a rotating magnetic field about the axis of the workpiece 70 as the center of rotation. Note that the holding member 60 holds the workpiece 70
It can be moved to the side so that it does not get in the way when installing or removing. 72.74.76 indicates a bearing.

The machining liquid placed in the container 34 is a mixture of magnetic fluid and abrasive grains. The magnetic fluid has colloidal size (
It is a colloidal solution in which ferromagnetic powder (150 Å or less) is dispersed, has superparamagnetic properties, is not easily magnetically saturated, and does not exhibit hysteresis. Normally magnetite 1~(1:e
30a) is used as a dispersoid, and water, hydrocarbon, ester, diester, hydrogen fluoride, etc. are used as a dispersion medium. As the abrasive grains, for example, diamond particles are used when the workpiece is ceramics, and alumina particles are used when the workpiece is metal.

The effects of the above embodiment will be explained below.

When the electric motor 50 is driven, the magnets 58 and 42 of the upper and lower rotating magnet holding members 60 and 44 rotate synchronously to generate a rotating magnetic field, and the magnetic fluid is magnetized and drawn by the rotating magnetic field. The workpiece 70 is rotated as shown in FIG.
A swirling flow is generated around the arrow in the direction of the arrow. As a result, the abrasive grains in the machining fluid are also dragged and moved in the same direction, colliding uniformly with the outer periphery of the workpiece, and the surface of the workpiece rtl! Polishing is done. The abrasive grains polish the surface of the workpiece while moving along the swirling flow with the workpiece axis as the center of rotation.
Even when the rotation precision of the magnetic field is poor, the rotation of the magnetic fluid approaches a perfect circle due to the inertia of the fluid, so that the abrasive grains often collide with the protrusion 80 of the workpiece 78 as shown in FIG.
It is particularly well polished and improves the roundness of the workpiece.

It is also possible to discontinue the attachment of the upper holding member 60 in the embodiment described above, and to use two magnets for the upper holding member 44 and attach them in a state where they are held on both sides. In addition, holding part 0
Instead of 44.60, a rotating magnetic field may be generated by providing a plurality of field coils above and below the container 34 and applying multiphase voltages.

Although one embodiment of the present invention has been described above, the present invention is not equally limited to such an embodiment and can of course be implemented in various forms without departing from the gist of the present invention. be.

[Effects of the Invention] As described in detail above, according to the present invention, a rotating magnetic field can be generated with the axis of the workpiece to be installed in the machining fluid container as the rotation center by the rotating magnetic field generating device. As a result, a swirling flow of the magnetic fluid with the rotation center as the center of rotation is generated around the workpiece, and the abrasive grains in the machining fluid are also pulled by this swirling flow. As a result, the protrusions are well rounded and the roundness of the workpiece can be improved.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a first conventional example of a surface polishing apparatus, FIG. 2 is a cross-sectional view of the second conventional example, and FIG. 3 is a cross-sectional view of a third conventional example. FIG. 4 is a sectional view showing an embodiment of the present invention, FIG. 5 is an explanatory diagram of the operation of the embodiment, and FIG. 6 is an explanatory diagram of a workpiece to which the embodiment is applied. 34... Container 44... Lower rotating magnet holder (rotating magnetic field generator 60
... Upper rotating magnet holder (rotating magnetic field generator 70.7
8... Workpiece Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. A workpiece attachment part is provided, which can be attached while the workpiece is immersed in a container containing a machining liquid made of a magnetic fluid mixed with abrasive grains, and a workpiece mounting part is provided outside the container. A surface comprising: a rotating magnetic field generating device that generates a rotating magnetic field around the axis of the workpiece; the surface is configured to generate a swirling flow of machining fluid around the axis of the workpiece; Polishing equipment. 2. The rotating magnetic field generator is provided with magnets on both ends of an extension line of the workpiece axis so that they can be driven to rotate in synchronization with each other with the extension line as the rotation center, and the magnets are arranged with different magnetic poles facing each other. A surface polishing apparatus according to claim 1, which is a surface polishing apparatus according to claim 1.