JPH02190251A - Spherical body machining device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a processing device for processing spheres of various materials such as ceramic spheres, resin spheres, fiber-reinforced resin spheres, and metal spheres.

(Prior Art) Recently, the excellent mechanical properties of ceramics have been utilized to manufacture spheres as mechanical parts. For example, spheres provided in bearings used under high-temperature conditions are manufactured from silicon nitride sintered viscous material, which has excellent high-temperature strength.

Generally, when manufacturing ceramic spheres, a rough sphere is formed from a sintered body, then the rough sphere is processed to form an intermediate sphere, and the sphere is further processed to form a highly spherical sphere. A finishing process is used. For example, the sphericity required for bearing spheres is on the order of submicrons.

Therefore, the following processing equipment is conventionally used for finishing processing of spheres. In other words, this sphere machining device has an upper disk and a lower disk having an annular groove shallower than the diameter of the sphere arranged vertically facing each other, and a sphere with poor precision is inserted into the annular groove of the lower disk along with slurry-like abrasive grains. Or put a grindstone at the bottom of the annular groove and put only the sphere into the annular groove.

Then, the sphere placed in the annular groove of the lower disk is held down by the upper disk and both disks are eccentrically rotated to process the sphere.

(Problems to be Solved by the Invention) However, such a conventional sphere processing device has the following problems.

That is, when a sphere is polished, shavings are generated from the sphere itself and from the disk, respectively, by the opposing objects.

However, in the structure of the conventional device in which a groove is provided in the lower disk, the shavings scraped off from the sphere and the disk by the abrasive grains are deposited in the annular groove of the lower disk, and the sphere passes over the annular groove. The hard shavings come into contact with the sphere, making the surface of the sphere rough and reducing its sphericity. In addition, because there are places where shavings have accumulated and places where they have not, the spheres on the areas where shavings have accumulated have been processed more than other spheres, and their diameters have increased compared to other spheres. The problem is that the difference between the spheres increases as the spheres become smaller.

The present invention has been made based on the above-mentioned circumstances, and an object of the present invention is to provide a sphere processing device that can eliminate the harmful effects of shavings and obtain spheres with high sphericity and good surface roughness.

[Structure of the Invention] (Means and Effects for Solving the Problems) The inventor of the present invention has developed a method for processing spheres such as resin balls, fiber-reinforced resin balls, metal balls, and ceramic balls with high sphericity and good surface roughness. We have conducted repeated research on this issue, but found that because conventional processing equipment had a groove for inserting the sphere into the lower disk, and the upper disk held down the sphere placed in the groove, the shavings of the sphere and disk were not removed from the groove. It was discovered that problems were occurring due to deposits in the grooves. Based on this, the inventor focused on the fact that the shavings move toward the outer periphery of the lower disk due to centrifugal force, and made the lower disk flat on the outer periphery of the sphere to easily and reliably discharge the shavings to the outside. We have developed a sphere processing device that can

That is, in the sphere processing device of the present invention, four parts are formed on the lower surface of the upper disc to prevent the sphere from moving toward the outer circumference of the disc, and between the lower face located on the outer peripheral side of the four parts of the upper disc and the upper surface of the lower disc. It is characterized by forming a space part with.

One of the basic configurations of the sphere processing apparatus of the present invention will be explained with reference to FIG.

In the figure, 1 is an upper disk, and 2 is a lower disk, and both disks 1.2 are arranged vertically facing each other.

The upper disk 1 has a vertical rotating shaft 3 installed above at the shape center 0□, and the lower disk 2 has the rotating shaft 3 of the upper disk 1 attached.
A vertical rotating shaft 4 provided below is attached at a position 02 eccentric from the center of the drawing, and both rotating shafts 3 and 4 are rotationally driven by a rotating device (not shown). Further, the lower surface of the upper disk 1 is formed with a flat recess 5 in the portion excluding the outer circumferential portion, and this recess 5 is formed by the sphere S disposed between the two rotating disks 1.2.
The ball S is pressed down from above, and the stepped wall surface 5a forming a boundary with the outer circumference prevents the sphere S from flying out toward the outer circumference of the disc. The depth of this four part 5 is smaller than the diameter of the sphere S. In addition, the upper surface of the lower disk 2 is formed with a recess 6 having a flat surface shape except for the central part. This prevents S from moving toward the center of the disk. The depth of this recess 6 is shallower than the diameter of the sphere S. Further, a gap 7 is formed in an annular portion between the outer circumferential portion of the lower surface of the upper disk 1 and the outer circumferential portion of the upper surface of the lower disk 2. This gap 7 communicates with the recess 6 of the lower disc 2, and serves as an outlet for discharging the shavings produced by machining the sphere S to the outside of the disc. That is, by forming the recess 5 for holding the sphere S in the upper disc 1, the outer peripheral part of the lower disc 2 can be made flat, thereby making it possible to form the cavity (exhaust port) 7. Incidentally, an abrasive grain supply port 8 is formed in the upper disk 1.

Therefore, when processing a sphere S made of ceramics, for example, the sphere S is placed in an annular space between the recess 5 of the upper disk 1 and the recess 6 of the lower disk 2, which are sandwiched between the stepped wall surfaces 5a and 6a. The upper disc 1 and the lower disc 2 are rotated in opposite directions by a rotating shaft 3.4. Then, slurry-like free abrasive grains are supplied from the abrasive grain supply port 8 of the upper disk 1 to the space between the recesses 5.6 of the upper and lower disks 1.2 in which the spheres S are arranged. Then, the sphere S has both disks 1,
Polishing is performed while moving between the two recesses 5 and 6. This polishing process produces shavings from the sphere S and the hundred disk 1°2, respectively. The generated shavings spread radially due to the centrifugal force caused by the rotation of the hundred disks 1 and 2, move toward the outer circumference of the disks, and further pass through the annular gap 7 formed between the outer circumferences of the hundred disks 1.2. and is ejected to the outside of the disc. In this way, the shavings generated by machining the sphere S are constantly discharged to the outside of the disk 1.2. That is, since the upper surface of the lower disc 2 is flat, the shavings are easily and reliably discharged to the outside of the disc by centrifugal force. Therefore, the shavings remain in the space between the recesses 5 and 6 of the hundred discs 1 and 2 and do not accumulate. Therefore, the sphere S can be processed well without coming into contact with shavings, and its surface roughness and sphericity can be improved. Further, the increase in the mutual difference between the spheres S due to the deposit of shavings is also eliminated.

FIG. 2 shows another example of the basic configuration of the sphere processing apparatus of the present invention, and the same parts as in FIG. 1 are given the same reference numerals.

In this embodiment, the upper disk 1 is used as the concave portion that presses the sphere S.
An annular groove 9 centered on the rotation center is formed on the lower surface of the holder. In this configuration, a grindstone is more suitable as an abrasive grain than a free abrasive grain, and an upper disc 1 is placed on the upper surface of a lower disc 2.
An annular grindstone 10 is buried opposite the groove 9. The entire upper surface of the lower disk 2 is a flat surface, and a gap 7 is formed between the outer circumference of the lower surface of the upper disk 1 and the outer circumference of the upper surface of the lower disk 2.

However, when processing the sphere S again, the groove 9 of the upper disk 1
A sphere S is placed in the space between the lower disk 2 and the grindstone 10, and the hundred disks 1 and 2 are rotated. As a result, the sphere S is processed by the grindstone 10 while rotating. The shavings produced by this machining are moved by centrifugal force and are discharged to the outside of the disc through the cavity 7. Therefore, 100 yen board 1.
No shavings remain between the two, allowing the sphere to be machined with high precision.

The sphere machining apparatus of the present invention is suitable for machining spheres with a diameter of 6.0 mm or less.

Moreover, the sphere processing apparatus of the present invention is not limited to ceramic spheres, but can also be applied to the processing of resin spheres, fiber-reinforced resin spheres, and metal spheres.

(Example) Example 1 of the present invention will be described.

Silicon nitride powder to which 10 parts by weight of a sintering aid was added was press-molded, degreased, sintered, and roughly processed to prepare a ceramic sintered body with a diameter of 5 m11.

Then, a ceramic sintered body was processed using the processing apparatus shown in FIG. 1 for the purpose of obtaining a sphere with a diameter of 4.75 mm from this roughly processed sphere. Sphere S is placed in the annular groove with a depth of 3.5m+* provided in the upper and lower disks respectively.
A slurry of diamond abrasive grains with a diameter of 4 to 8 μm was added, and the upper disk 1 was rotated counterclockwise at 20 rpa+, and the lower disk 2 was rotated clockwise at 30 rpm.
The surface roughness, sphericity, and mutual difference were measured and compared for a time-processed sphere and a sphere processed by the conventional method of providing grooves on the lower disk (processing conditions are the same as the examples of the present invention). As a result, the surface roughness of the comparative example was 0.072.
μl, sphericity 0.48 μm, and mutual difference 0.85 μω, whereas in the example of the present invention, the surface roughness was 0.018 μm,
Sphericity 0.15μm, mutual difference 0.29μm and surface roughness.

It was found that the sphericity and mutual difference were also highly accurate.

Example 2 of the present invention will be described.

Silicon nitride powder to which 10 parts by weight of a sintering aid had been added was press-molded, degreased, sintered, and roughly processed to prepare a ceramic sintered body with a diameter of 3.5 mm.

Then, from this roughly processed sphere, a diameter of 3.175 mm was obtained.
A ceramic sintered body was processed using the processing apparatus shown in FIG. 2 with the aim of obtaining a sphere of . A sphere S is placed in an annular groove with a height of 2.5+am and a width of 60am provided on the upper disk.
was charged, and processing was performed using a grindstone in which diamonds of 5 to 10 μm were embedded in the lower disk. Top disc 1 is 30
The sphere was machined for 60 hours by rotating the lower disk 2 counterclockwise at 45 rpm and the lower disk 2 was processed clockwise at 45 rpm, and the lower disk 2 was processed using a conventional method (using a grindstone) in which grooves were provided in the lower disk (using a grindstone). The surface roughness, sphericity, and mutual difference of the spheres (same as the present invention example) were measured and compared. the result,
Comparative example has surface roughness of 0.185μ■ and sphericity of 0.59μ
l Mutual difference was 1.03 μm, whereas in the example of the present invention, the surface roughness was 0.055 μm, the sphericity was 0.28 μm, and the mutual difference was 0.41 μm, and the surface roughness, sphericity, and mutual difference were also It was found that the accuracy was high.

[Effects of the Invention] As explained above, according to the sphere machining device of the present invention, the shavings generated during the machining of the sphere can be discharged to the outside of the disk, and the sphere can be machined well, improving surface roughness, sphericity, and Highly accurate spheres can also be obtained with respect to mutual differences.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams showing a sphere processing apparatus of the present invention. DESCRIPTION OF SYMBOLS 1... Upper disk, 2... Lower disk, 3... Rotating shaft, 4... Rotating shaft, 5.6... Recessed part, 7... Gap part, 9... Recessed part, 10 ...Whetstone, S...Sphere.

Claims (1)

[Claims] In an apparatus for processing a sphere by sandwiching a sphere between an upper disk and a lower disk arranged vertically opposite each other and rotating both disks, the lower surface of the upper disk prevents the sphere from moving toward the outer circumference of the disk. A sphere machining device characterized in that a recess is formed, and a gap is formed between a lower surface of the upper disk located on the outer peripheral side of the recess and an upper surface of the lower disk.