JPH029567A - Polishing device employing magnetic fluid - Google Patents

Abstract

PURPOSE:To reduce vibration of a guide ring during polishing and to improve roundness and the polishing efficiency of a ball body by a method wherein the inner wall surface of the guide ring is lined with friction resistant rubber. CONSTITUTION:A spherical substance 3 to be polished is polished in roundness in a way that a drive lap 1 is rotated in a state that the substance to be polished is held in magnetic fluid 7 by means of the drive lap 1, a float 5, on which buoyancy is exerted togetherwith the magnetic fluid 7 by means of a magnetic field generated by a magnetic field generating means 6, and the inner wall surface of a guide ring 4. In this case, in order that vibration of the guide ring 4 is suppressed during polishing of the substance 3 to be polished, the inner wall surface of the guide ring 4 is lined with a lining material, e.g. friction resistant polyurethane rubber. This constitution enables improvement of roundness of the substance 3 to be polished to an extremely high value and shortening of a polishing time.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a polishing device using a magnetic fluid, and more specifically, a polishing device that uses a magnetic fluid containing abrasive grains under the action of a 61 field to polish ball bearings, etc. This invention relates to an apparatus for efficiently manufacturing spheres with high sphericity by polishing spheres used in

[Prior Art] Conventionally, a method and apparatus for polishing spheres used in ball bearings, etc. using a polishing liquid made of a magnetic fluid containing abrasive grains under the action of a magnetic field has been disclosed in Japanese Patent Laid-Open No. 17316/1983.
It is disclosed in Publication No. 6.

The polishing method and device described in the publication apply ejection force to a sphere immersed in a magnetic fluid containing abrasive grains by the action of an external magnetic field acting from one side outside the magnetic fluid.
It is pressed against the surface of the first-shift jig (Kanno-lap) located at the opposite M; 1, thereby transmitting the movement of the drive jig to the sphere and causing it to move in the magnetic fluid containing abrasive grains. let me,
It is characterized in that the movement of the sphere is controlled by a guide surface.

Also, at this time, if a buoyant plate (float) is inserted so as to be located on the external magnetic field side of the sphere, a discharge force is also applied to this buoyant plate due to the action of the external 6n field, which makes the sphere stronger in contact with the driving jig. It is disclosed that the polishing efficiency is significantly improved because the polishing is applied to the surface.

In the polishing device, in order to control the movement of the sphere, 1. A V-shaped groove or a partition plate is provided on the lower surface of the driving lap to function as a guide surface for the movement of the sphere, thereby improving polishing efficiency and sphericity. We are trying to Another method is to make the lower end of the drive wrap into the shape of a triangular pyramid at every position, so that the sphere has an inverted triangular pyramid with an inclined surface.
When using conventional polishing equipment such as this, polishing is performed by moving the material between a cylindrical container (gaitonog) and a buoyant plate to improve its sphericity. However, the sphericity of the obtained spheres is not necessarily sufficient, and the polishing efficiency is also not satisfactory.

[Problems to be Solved by the Invention] The guide rings disposed in such conventional polishing devices are often made of metal, and the parts that come into contact with the spheres tend to wear out over time. guide ring,
There was a limit to the improvement in sphericity and polishing efficiency due to fluctuations in the positional relationship between the lap, float, and sphere.

The present invention provides 6! containing abrasive grains! It is an object of the present invention to provide a polishing device that uses a U-based fluid and further improves the sphericity of spheres and the polishing efficiency.

[Means and Effects for Solving the Problems] In order to achieve the above object, the inventors of the present invention, as a result of careful consideration, have solved the problem by lining the inner wall surface of the guide ring with a wear-resistant rubber material. By matching with the driving lap and the float, the present invention has been completed in which the guide ring is hardly captured during LLa, and the sphericity and polishing efficiency of the sphere are greatly improved.

That is, the present invention includes a guide ring, a float immersed in a 6N fluid containing abrasive grains, a rotatable drive wrap, and a magnetic field formed in the magnetic fluid to provide a levitation force to the float together with the magnetic fluid. A polishing device that polishes a spherical object to be polished by rotating the driving lap while holding the spherical object in the magnetic fluid by the driving lap, a float receiving a buoyancy force, and the inner wall surface of a guide ring. A polishing device characterized in that the inner wall surface of the guide ring is lined with wear-resistant rubber.

Hereinafter, a polishing apparatus using a magnetic fluid according to the present invention will be explained based on the drawings.

FIG. 1 is a sectional view showing an example of the polishing apparatus of the present invention.
In the figure, 1 is the driving lap, 2 is the contact surface of the lower end of the driving lap with the spherical object to be polished, and 3 is the spherical corrugated object (the spherical object to be polished).
, 4 is the guide ring, 5 is the float, 6 is the magnet, 7 is the magnetic fluid containing abrasive grains, E is the rough, and l) the inclination angle of the contact surface at the lower end of the wrap.The polishing apparatus shown in FIG. So,
The float 5 is immersed in a magnetic fluid 7 containing abrasive grains, and an external magnetic field is applied to the magnetic fluid 7 using a magnet, etc., to give buoyancy to the float 5 (the buoyancy causes the float 5 to rise, and ; ■ The sphere 3 is held by the contact surface of the upper end of the float 5, the contact part 2 of the lower end of the drive wrap 1, and the inner wall of the guide ring 4.Then, by driving the drive wrap 1 and rotating it in the horizontal direction, The motion caused by the rotation is transmitted to the spherical object 3 to be polished, and it comes to move in the magnetic fluid 7 containing abrasive grains.There is a relative movement between the spherical object 3 to be polished and the magnetic fluid 7 containing abrasive grains. As a result, polishing is efficiently performed on the surface where the spherical object 3 to be polished is held, particularly on the tapered contact surface 2 at the lower end of the drive lap 1.

The drive lap 1 shown in the polishing apparatus of FIG. 1 is capable of horizontal rotation about a vertical axis and has a contact surface 2 at its lower end. Further, since the driving lap 1 is worn out by polishing the spherical body 3 to be polished, it is necessary to lower the driving lap 1 each time, so that vertical movement is also possible. This contact surface 2 plays an important role in holding the spherical object 3 to be polished on the orbit between the float 5 and the inner wall surface of the guide ring 4, and for stable and smooth rotational polishing. Contribute to the improvement of Here, when the inclination angle E of the contact surface 2 in the outer circumferential direction with respect to the vertical direction is 20 to 80 degrees, the sphericity of the sphere can be improved. If the inclination angle E of the contact surface 2 exceeds 80 degrees, the force pressing the sphere 3 to be polished against the inner wall surface of the guide ring 4 will be weak, and if it is less than 20 degrees, the contact surface will not effectively press the sphere 3 to be polished. Since no processing pressure is applied from 2,
In each case, the motion of the polished sphere 3 becomes unstable and the sphericity does not improve, which is not preferable.

Further, other shapes of the drive wrap 1 may be cylindrical, and in this case as well, the angle of inclination E of the contact surface is preferably in the range of 20 to 80 degrees.

The material of the drive lap 1 is not particularly limited in the case of rough machining, and examples include stainless steel such as 5OS304, metals such as brass and aluminum, and in the case of finishing, brittle materials such as cast iron and ceramics. Alternatively, one made of resin or the like is preferable.

A guide ring 4 provided in the polishing apparatus shown in FIG. 1 keeps the polished sphere 3 rotating together with the contact surface 2 of the driving lap 1 and the float 5 constant during polishing, thereby contributing to improving the sphericity of the sphere. do.

In the present invention, a lining is provided on the inner wall surface of the guide ring 4 in order to suppress vibration of the guide ring during polishing of the sphere. Lining materials used here include wear-resistant polyurethane rubber, natural rubber, synthetic natural rubber (polyisoprene rubber), styrene-butadiene rubber copolymer, polybutadiene rubber and nitrile-butadiene copolymer rubber, and fluororubber. , chloroprene rubber, chlorosulfonated polyethylene rubber or mixtures of these rubbers, as well as wear-resistant plastics such as Teflon,
Polyamide and the like are preferably used.

Next, the float 5 immersed in the magnetic fluid of the polishing device is
Buoyancy is applied by the action of an external magnetic field such as the magnet 6, and the float 5 floats to strongly press the spherical object 3 to be polished against the contact surface 2 of the lower end of the drive lap 1. This float 5 is
Together with the contact surface 2 of the driving lap 1 and the inner wall surface of the guide ring 4, the rotating spherical object 3 to be polished is held constant during polishing, contributing to improvement in sphericity. The shape of the float 5 in contact with the spherical object 3 to be polished may be a flat or tapered shape that makes contact at one point, or a V-shaped cross section or an R-shaped concave shape that makes contact at two points or a circumferential portion. A recessed portion may be provided.

As the material of the float 5, various materials such as metal, plastic, ceramics, rubber, etc. can be appropriately selected and used.

The buoyant force acting on the float 5 is determined by the strength of the external magnetic field acting from below, the size of the float 5, the distance from the magnet 6 etc. to the float 5, etc., and by changing these, the required processing pressure can be controlled arbitrarily. can do.

It is not an absolute condition that the specific gravity of the 4 particles 5 is higher than the ratio 1 of the magnetic fluid 7 containing abrasive grains, but the external b acting from below is not an absolute condition.
Any material that generates buoyancy due to the action of the n-field may be used.

61 As the injection fluid 7, one in which ferrite, magnetite, etc. is dispersed using water or oil as a medium is used.

As the abrasive grains contained in the magnetic fluid 7, known polishing abrasive grains can be appropriately selected and used. For example AQ203
(corundum), 5iC (silicon carbide: carborundum), diamond, etc., or abrasive grains with added magnetism may be used.

The magnet 6 used as the external magnetic field may be a single magnet or a group of magnets arranged with the same polarity, but it is rather arranged so that the polarities of adjacent magnets are different from each other (as indicated by the arrows in the figure).
Combining magnet groups such that the poles of adjacent magnets are different from each other increases the buoyancy of the abrasive grains and the float 5, and also causes a magnetic ejection force to act in the horizontal direction, thereby reducing the This is to hold the abrasive grains against the direction of movement of the polishing sphere 3. This BN stone or magnet group may be a permanent magnet or an electromagnet.

Further, as the polished sphere 3 applicable to the present invention, Si
A material made of ceramic or metal such as C, Si3N4, etc. is used, and the polished sphere is used for applications such as ball bearings.

In addition, although the spherical object to be polished has been described in the present invention,
It is possible to polish not only spherical objects but also flat plates, cylinders, etc.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

In the polishing apparatus shown in FIG. 1, a polishing test was conducted using lining materials made of polyurethane rubber, nitrile-butadiene copolymer rubber, and polyisoprene rubber on the inner wall surface of the guide ring, respectively. In this case, the drive wrap was made of 5tlS304 and had a contact surface of 60 degrees. The float was made of acrylic and had a flat shape with a thickness of 21II. The polishing test conditions are as follows.

MA magnetic fluid polished sphere, number of spheres Diameter of sphere Sphericity W-40 (manufactured by Taiho Industries) Si, N4, 11 balls 11 balls 7.1a+a+ 2μm Polishing abrasive grains SiCGC#6000 Polishing time
40 minute drive lap rotation speed 9000r, p, m.

The results of Examples 1 to 3 are summarized in Table 1.

Comparative Examples 1-2 A polishing test was conducted under exactly the same conditions as Examples 1-3, except that the guide ring was used as it was without applying a lining material to the inner wall surface of the guide ring. As the material of the guide ring, 5tlS-:104 and brass were used.

Comparative Example 3 Silicone rubber was applied as a lining material to the inner wall surface of the guide ring, and a polishing test was conducted under exactly the same conditions as in Examples 1 to 3.

The test results of Comparative Examples 1 to 3 are shown in Table 1 together with the results of Examples 1 to 3.

Table 1 is obtained. Furthermore, by improving polishing efficiency, polishing time is shortened and economical efficiency is improved.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an example of a polishing apparatus according to the present invention. As is clear from the above examples and comparative examples, when polishing is performed using a guide ring lined with wear-resistant rubber in a polishing device, the comparison is made when polishing is performed using a metallic guide ring. It can be seen that the sphericity is extremely improved. [Effects of the Invention] As explained above, according to the polishing apparatus using the magnetic fluid of the present invention, a sphere with extremely improved sphericity; a driving lap; : a contact surface of the lower end of the driving lap; : a sphere to be polished; Ni guide ring, : Float, : Magnet, : Magnetic fluid containing abrasive grains, Inclination angle of the contact surface of the lower end of the Ni g1 roll.

Claims (1)

[Claims] 1. A guide ring, a float immersed in a magnetic fluid containing abrasive grains, a rotatable drive wrap, and a magnetic field forming means that forms a magnetic field in the magnetic fluid to give a levitation force to the float together with the magnetic fluid. In a polishing apparatus that polishes a spherical object to be polished by rotating the driving lap while holding the spherical workpiece in the magnetic fluid by the driving lap, a float receiving a buoyant force, and an inner wall surface of the guide ring, the guide A polishing device characterized by a wear-resistant rubber lining on the inner wall surface of the ring.