JP2620888B2 - Manufacturing method of micro metal ball material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a metal ball such as a steel ball material for a bearing, a mill ball, a ball tip for a ballpoint pen, a bullet of a shotgun, and the like.

[Prior art] For example, the conventional method of manufacturing a steel ball of about 2 mm in diameter is to cut a steel wire of 2 mm or less in diameter slightly longer than its diameter, press it with a heading machine, and vertically cut it. It is crushed into a mayu shape, and then tumbled by a rolling machine to produce steel balls having a smooth surface.

[Problems of the prior art]

However, in a press using a heading machine as in the above-mentioned conventional method, it was only possible to form a cut cylindrical steel wire into a cocoon shape. The yield was very poor (about 50%), the material wasted, the polishing time was long, and the productivity was poor.

[Means for Solving the Problems] The method for producing a fine metal ball material of the present invention is intended to solve the problems of the above-described conventional method for producing a steel ball, and a metal wire having a length slightly shorter than its diameter. Cut into a large number of cylindrical bodies, the cylindrical bodies are accelerated at high speed by acceleration means such as rotating blades or air jets to cause the cylindrical bodies to collide with hard wall surfaces at high speed. Rounding by crushing the corners without crushing the columnar body by collision,
By repeating this collision many times, the columnar body is gradually made spherical.

[Action]

By repeatedly accelerating and colliding, the cylindrical body cut to a length slightly shorter than the diameter gradually approaches a sphere, and a steel ball having a desired roundness is obtained.

〔Example〕

Fig. 1 shows an example of a wire cutting machine. In the drawing, reference numerals 1a to 1d denote metal wires made of high-carbon chromium bearing steel having a diameter of 2.6 mm, and reference numerals 2, 3 denote the wires 2, 3 with the wires 2, 3 facing the table 4. A roller that feeds at a speed. Reference numeral 5 denotes a portion where a cutting blade is provided on the outer periphery and a rotating blade material that rotates at the extreme end of the table 4 is provided, where the tips of the plurality of wires 1a to 1d protrude from the edge of the table 4. The cutting blades of the rotating blade material intersect and cut the wires 1a to 1d to a length of 2.3 mm.
As shown in the figure, a large number of columnar bodies 6 are continuously extracted on the receiving trough 7.

Next, the columnar body 6 is passed through a circulating impact device as shown in FIG. In this apparatus, a rotating blade 10 which is rotated at a high speed by a motor is provided in a chamber 9 having a hard wear-resistant wall surface 8 on an inner peripheral surface. The rotating blades 10 are provided with a plurality of blades radially provided on a peripheral surface of a wheel, and a material supply pipe 13 connected to a hopper 12 faces an input port 11 opened at one side of the center. Reference numeral 14 denotes a bucket conveyor which is assembled so that the material which has flowed down from the chamber 9 through the swash tube 15 can be scooped up by the bucket conveyor 14 and circulated to the hopper 12. Reference numeral 16 denotes an inlet, and 17 denotes an outlet.

Thus, the columnar body 6 is charged from the inlet 16 and is lifted by the bucket conveyor 14 to reach the hopper 12,
The material is supplied to the center of the rotary blade 10 through the material supply pipe 13.
Since the rotating blades 10 are rotating at a high speed, the columnar body 6 is accelerated by its centrifugal force and is scattered radially at a high speed to collide with the hard wall surface 8 and the impact pushes the corner of the columnar body 6. Crushed. The columnar body 6 having collided with the wall surface 8 flows down the swash tube 15 by its own weight, is again pumped by the bucket conveyor 14, is supplied to the rotating blades 10 from the hopper 12, is accelerated again at a high speed, and collide with the wall surface 8. In this way, the columnar body 6 is circulated many times and repeatedly hit.

The following table is shown in FIG. 4 obtained when the collision was repeated by circulating a cylindrical body having a diameter of 2.6 mm and a length of 2.3 mm through the above-mentioned circulating impact device for 20, 30 and 40 minutes, respectively. These are measured values (measured for each of five pieces) of dimensions X and Y of a deformed spherical body and their ratios. In addition, it is estimated that the collision of the columnar body was repeated about 100 times in 20 minutes, 150 times in 30 minutes, and 200 times in 40 minutes.

By repeating the collision in this way, X and Y gradually become closer to each other and the roundness can be increased. In this embodiment, a steel ball having a diameter of about 3 mm could be manufactured.

The steel ball produced in this way is used for shot blasting as it is, or further applied to a rolling machine to rotationally grind the surface and used for bearings and other uses.

In addition, the following table shows that the lengths of cylindrical bodies are 2.3 mm, 2.4 mm, and 2.5 mm (each diameter is 2.6 mm).
Of deformed sphere after one and 300 collisions
The measured values of X and Y and their ratios are shown.

According to this, it is understood that the roundness of the columnar body having a diameter of 2.6 mm is most easily achieved with a length of 2.3 mm.

In this embodiment, a plurality of wires can be cut simultaneously by a cutting machine having a rotary blade as shown in FIG. 1, so that a large number of cylindrical bodies can be manufactured in a short time, Since a large number of columnar bodies can be continuously processed also in the processing step, steel balls can be manufactured with extremely high production efficiency.

In this embodiment, the rotating blades are shown as the accelerating means for the columnar body. However, as the accelerating means for the cylindrical body, in addition to using the centrifugal force generated by the rotating blades, the compressed air is ejected at a higher speed than the nozzle. The cylindrical body may be accelerated by inserting the cylindrical body into the injection portion, and may collide with a hard wall surface.

[Effects of the Invention] As described above, the method for producing a fine metal sphere material of the present invention requires only accelerating a cylindrical body obtained by cutting a metal wire to a length slightly shorter than the diameter at a high speed and colliding against a hard wall surface. High roundness steel balls can be manufactured. Therefore, there is an economically beneficial effect that steel balls having a high roundness can be manufactured more efficiently and in a shorter time than the conventional processing using a head, and the yield of products is greatly improved.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show one embodiment of the method for producing a fine metal ball material according to the present invention, FIG. 1 is a schematic side view of a wire cutting machine, FIG. 2 is a perspective view of a columnar body, and FIG. FIG. 4 is a longitudinal sectional view of the circulation impact device, and FIG. 4 is a front view of the deformed spherical body. 1a to 1d: metal wire, 5: rotating blade material, 6: cylindrical body, 8: wall surface, 10: rotating blades, 11: inlet, 14
...... Bucket conveyor.

Claims (1)

(57) [Claims] 1. A metal wire is cut to a length slightly shorter than its diameter to form a large number of cylindrical bodies, and the cylindrical bodies are accelerated at high speed by a rotating blade or an acceleration means such as air jet. The columnar body is caused to collide with a hard wall surface at a high speed, and by this collision, most of the columnar body is crushed and rounded without being divided, and the collision is repeated many times to thereby form the circle. A method for producing a fine metal sphere material, wherein the columnar body is gradually made spherical.