JP2001330404A - Method and apparatus for selecting spherical body and method for manufacturing spherical body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for selecting a spherical body and a method for manufacturing a spherical body, which can reduce the cost for the screening and inspection of a spherical body and improve the inspection accuracy regardless of the skill level. I do. For example, when the deformation amount Δd of the spherical body is relatively large, the rolling friction force F becomes large, so that the time required for rolling down and passing through a predetermined section of the inclined path becomes relatively long. It is sufficient to sort the object to be sorted into any of a plurality of ranks in accordance with the required time for dropping, so that the cost of the inspection for sorting the spherical bodies can be reduced, and the inspection accuracy can be improved regardless of the skill level. Therefore, it is not necessary to rely on a visual inspection using a magnifying glass or the like, and furthermore, it is easy to mechanize or automate, and problems such as deterioration of inspection accuracy due to oversight or limitation of sorting ability due to insufficient skill can be solved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for selecting a spherical body and a method for manufacturing a spherical body.

[0002]

2. Description of the Related Art Generally, spherical bodies made of ceramic, metal, etc., manufactured by sintering, forging, etc., are usually subjected to surface polishing to improve sphericity when used for bearings and the like. It is.

In addition, since silicon nitride ceramic balls have high strength and are excellent in wear resistance, they have recently been used for bearings of hard disks of machine tools and computers, or have been used for driving semiconductor devices by utilizing high-temperature corrosion resistance. It is used for bearings used in high temperature and corrosive special environments such as parts. In the case of such a ceramic ball for a bearing, precise surface polishing is often performed by a lapping machine having a fixed plate and a rotating plate.

[0004]

In the above-mentioned polishing, if a sphere which is significantly deformed in the manufacturing process is mixed, the sphericity of the polished ball is deteriorated or the lapping machine is damaged. Or had a problem. For this reason, an inspection of the degree of deformation of the spherical body before polishing is performed. For example, when the deformation amount exceeds a predetermined value, the ball is selected as a rejected product, and only the passed product is subjected to polishing. However, this inspection has so far relied on a visual inspection using a magnifying glass or the like, which has required a great deal of labor and time, and has been a factor of increasing the manufacturing cost. Moreover, since this inspection is a human operation, there have been problems such as deterioration of inspection accuracy due to oversight or the like, and limitation of sorting ability due to lack of skill.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method and an apparatus for selecting a spherical body and a method for manufacturing a spherical body, which can reduce the cost of the screening and inspection of the spherical body and can improve the inspection accuracy regardless of the skill level. Is to do.

[0006]

Means for Solving the Problems and Action / Effects In order to solve the above-mentioned problems, the method for selecting a spherical body according to the present invention is characterized in that the spherical object to be selected rolls, falls, and passes through a predetermined section of an inclined path. (Hereinafter referred to as a required drop time), and the selected objects are sorted according to the required drop time.

Further, in order to solve the above-mentioned problems, a spherical body sorting apparatus of the present invention provides an inclined path for rolling and dropping a spherical object to be sorted, and a time required for passing through a predetermined section of the inclined path ( (Hereinafter, referred to as a required drop time) and a selecting section that selects the object to be sorted according to the required drop time.

Further, in order to solve the above-mentioned problems, the method for producing a spherical body according to the present invention comprises rolling and dropping each of a plurality of spherically-shaped selected objects on an inclined path.
It is characterized in that a time required for passing through a predetermined section of the inclined path (hereinafter referred to as a required drop time) is measured, and the plurality of selected objects are sorted according to the required drop time.

Here, as shown in FIG. 12, when a spherical body rolls and falls on an inclined path, rolling resistance (rolling frictional force) is obtained.
Is known to depend on the properties (state) of the surface of the spherical body and the surface of the inclined path. That is, the rolling resistance changes depending on, for example, the material of both surfaces, unevenness (surface roughness and the like), and the degree of wetting (lubricating state, that is, presence or absence of an intermediate substance). In FIG. 12, when the gravitational force of the spherical body is W, the mass is m, the acceleration is a, the inclination angle of the inclined path is θ, the normal force is N, and the rolling frictional force is F, the spherical body follows the inclined path. It is considered that there is a uniform acceleration motion in the x direction.
The equations of motion in the directions are expressed by the following equations. W sin θ−F = ma (1) N−W cos θ = 0 (2) Here, assuming that the gravitational acceleration is g, W = mg (3), and the rolling friction force F is the rolling friction coefficient. μ
Then, F = μN (4) From equations (1) to (4), F = μWcosθ (5) a = g (sinθ−μcosθ) (6) is derived. On the other hand, it is known that the rolling friction force F is approximately inversely proportional to the radius r of the spherical body and proportional to the gravity W. That is, μ = f1 (F) = f2 (W / r) (7) However, in equation (7), f1 and f2 indicate that they are represented as functions having variables in parentheses.

The main cause of the generation of the rolling frictional force F in FIG. 12 is unevenness existing on the contact surface between the spherical body and the inclined path. In other words, deformation occurs between the contact surfaces due to the unevenness, and a force in a direction that impedes the progress from the inclined path surface acts on the spherical body surface. Therefore, the sphericity (deformation amount) of the spherical body is closely related to the magnitude of the rolling friction force F.
For example, when the deformation amount Δd of the spherical body is represented by the difference between the maximum diameter dmax and the minimum diameter dmin of the spherical body, the rolling friction force F is expressed as a function f3 having the deformation amount Δd of the spherical body as a variable. F = f3 (Δd) (8) Δd = dmax−dmin (9)

For example, when the deformation amount Δd of the spherical body is relatively large, the rolling frictional force F becomes large, so that the time required for rolling down and passing through a predetermined section of the inclined path (hereinafter referred to as “dropping time required”). Are also relatively long.
According to the present invention, for example, the object to be sorted may be sorted into any of a plurality of ranks in accordance with the required time for dropping, the cost for the sorting inspection of the spherical body can be reduced, and the inspection accuracy can be achieved regardless of the skill level. Can be improved. Therefore, it is not necessary to rely on a visual inspection using a magnifying glass or the like, and furthermore, it is easy to mechanize or automate, and problems such as deterioration of inspection accuracy due to oversight or limitation of sorting ability due to insufficient skill can be solved.

In the present invention, when the object to be sorted is selected as a pass or reject according to the time required for dropping, it is possible to further save labor in the inspection for selecting the spherical body and to improve the inspection efficiency. It greatly contributes to improvement.

Next, the inclined path of the present invention has a cross-sectional dimension larger than the diameter of the object to be sorted, and can be formed by a helical long hollow member. As a result of adopting a helical long hollow member, the inclined path and, consequently, the entire sorting apparatus can be made compact, the installation space is small, and even if the object to be sorted is rolled and dropped at a high speed, it jumps out of the inclined path. Don't worry. In addition, the use of a helical long hollow member causes a centrifugal force or the like to act on the selected object, causing the spherical body to rotate randomly, so that the rolling resistance (rolling frictional force) spreads evenly over the entire surface of the spherical body. It will be. Accordingly, when the spherical body rolls and falls on a predetermined section of the inclined path, the sphericity (for example, the deformation amount Δ
A speed difference reflecting d) is reliably generated, and spheroids can be easily sorted (for example, a good product and a bad product).

Here, when the long hollow member of the present invention is transparent or translucent, it is possible to externally confirm that the object to be selected rolls and falls inside the long hollow member. In the method of sorting one by one, it is easy to understand the timing of the next spherical body. In particular, when the object to be sorted is clogged in the long hollow member, the clogged state can be immediately found through the transparent or translucent long hollow member, and the countermeasure can be taken promptly.

Further, according to the present invention, the area ratio S1 / S2 satisfies 1 <S1 / S2 ≦ 15, where S1 is the cross-sectional area of the hollow portion of the long hollow member and S2 is the cross-sectional area of the object to be sorted. Can be set to By setting the area ratio S1 / S2 to this range, the surface of the spherical body comes into extensive contact with the inner surface of the elongated hollow member when the selected body rolls and falls, so that the rolling resistance (rolling friction force) is reduced. It acts on a wide area of the spherical body surface. Then, a difference in speed at the time of rolling and falling on a predetermined section of the inclined path is formed according to the sphericity (for example, the deformation amount Δd) of the spherical body. Sorting) can be performed easily.

If the area ratio S1 / S2 exceeds 15,
Since the inner surface of the elongated hollow member does not exert a sufficient influence force (rolling friction force) on the spherical body surface, a speed difference corresponding to the sphericity of the spherical body may not be sufficiently formed. On the other hand, when the area ratio S1 / S2 is 1 or less, the long hollow member is clogged with the sphere, and the sphere cannot be sorted.

Further, according to the present invention, when the inclination angle formed by the inclined path with respect to the horizontal line is θ, 0.5 ≦ θ ≦ 4 ° can be set. By setting the inclination angle θ in this range, the difference in the required drop time is sufficiently and stably formed according to the sphericity of the spherical body (for example, the deformation amount Δd). Measurement and sorting of spherical bodies (for example, sorting of acceptable and rejected products) is easy.

If the inclination angle θ exceeds 4 °, the spherical body may roll down the inclined path rapidly and fall, and the difference in the required drop time depending on the sphericity of the spherical body may not be sufficiently formed. is there. On the other hand, when the inclination angle θ is less than 0.5 °, the spherical body is unlikely to roll down the inclined path and fall down, and may stay on the inclined path.

As an example of a spherical body provided as a sorting object in the sorting apparatus of the present invention, for example, a typical application field of a spherical silicon nitride sintered body is a bearing ball, for example, a bearing of a hard disk of a machine tool or a computer. Or a ceramic ball used as a bearing ball or the like used in a high-temperature and corrosive special environment such as a driving portion of a semiconductor device utilizing high-temperature corrosion resistance.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION A spherical silicon nitride sintered body, for example, as an example of a spherical body provided as a sorting object to the sorting apparatus of the present invention will be described together with an example of a method of manufacturing the same. The silicon nitride-based sintered body is mainly composed of silicon nitride, and the remaining component includes a sintering aid component, and 3A, 4A, 5A, 3B (for example, Al) in the periodic table.
And at least one element selected from the group consisting of Mg and 4B (for example, Si) and 1 to 10% by weight in terms of oxide.
It can be contained. These exist mainly in the oxide state in the sintered body. If the sintering aid component is less than 1% by weight, it is difficult to obtain a dense sintered body, and if it exceeds 10% by weight, insufficient strength, toughness or heat resistance is caused. It also leads to a decline. The content of the sintering aid component is desirably 2 to 8% by weight.
In addition, at the time of compounding the raw materials, in addition to oxides of these elements, compounds which can be converted into oxides by sintering, for example, carbonates and hydroxides may be added. Molding of the compounded raw material powder can be performed using a pressure molding method such as a mold press, and a desired shape can be obtained.

The sintering aid component of group 3A includes S
c, Y, La, Ce, Pr, Nd, Sm, Eu, Gd,
Tb, Dy, Ho, Er, Tm, Yb, and Lu are generally used. The content of these elements R is RO only for Ce.
₂ and others are calculated using R ₂ O ₃ type oxides. Of these, oxides of heavy rare earth elements of Y, Tb, Dy, Ho, Er, Tm, and Yb are preferably used because they have the effect of improving the strength, toughness, and wear resistance of the silicon nitride sintered body. used.

The structure of the silicon nitride-based sintered body has a form in which main phase crystal grains containing silicon nitride as a main component are bonded by a vitreous bonding phase. The main phase is composed of Si ₃ having an α conversion of 70% by volume or more (preferably 90% by volume or more).
It may be from essentially provided by a N ₄ phase. In this case, S
The i ₃ N ₄ phase is a phase in which Si or N is partially substituted with Al or oxygen, and further, Li, Ca,
It may be a solid solution of metal atoms such as Mg and Y.
For example, it can be exemplified Sialon which is expressed by the following general formula; _{beta-sialon: Si 6-Z Al Z O} Z N 8-Z (z =
0 to 4.2) _{alpha-SiAlON: M X (Si, Al)} 12 (O, N)
₁₆ (x = 0 to 2) M: Li, Mg, Ca, Y, R (R is a rare earth element excluding La and Ce).

The sintering aid component mainly constitutes a glass phase, but a part thereof may be taken into the main phase. The glass phase may contain unavoidable impurities, for example, silicon oxide contained in the silicon nitride raw material powder, in addition to components intentionally added as a sintering aid.

In this specification, the term “main component” is used.
The term “subject” or “mainly” means that the content of the substance of interest is 50% by weight or more, unless otherwise specified.

When a ceramic ball such as a bearing ball is manufactured, it is desirable to employ the following method in order to improve efficiency. FIG. 1 shows an embodiment of an apparatus used in the raw material powder preparation step. In the apparatus, the hot air flow passage 1 is formed to include a vertically arranged hot air duct 4, and a gas flow member that allows hot air to pass therethrough and does not allow the drying medium 2 to pass therethrough, in the middle of the hot air duct 4. For example, a media holding unit 5 formed of a net or a perforated plate is formed. Then, on the medium holding portion 5, the dry media 2 composed of ceramic spheres mainly composed of any one of alumina, zirconia, and their mixed ceramics are accumulated, and a layered dry media aggregate 3 is formed. .

On the other hand, the raw material is in the form of a slurry obtained by adding a water-based solvent to a blend of silicon nitride powder and a sintering aid powder and wet-mixing (or wet-mixing / grinding) with a ball mill or an attritor. Be prepared.

As shown in FIG.
On the other hand, the hot air is circulated in the hot air duct 4 so as to move upward from the lower side of the medium holding portion 5 while moving the drying medium 2 up. On the other hand, as shown in FIG.
Is pumped up from the slurry tank 20 by the pump P, and is dropped and supplied to the dry media assembly 3 from above. Thereby, as shown in FIG. 3, the slurry is dried by hot air and adheres to the surface of the drying medium 2 in the form of the powder aggregation layer PL.

Then, by the flow of the hot air, the dry media 2 repeatedly hits and falls and hits each other, and the powder agglomeration layer PL is crushed into the raw powder particles 9 by the rubbing caused by the hits. The crushed raw material powder particles 9 include those in the form of isolated primary particles, but are mostly secondary particles in which the primary particles are aggregated.
The raw material powder particles 9 having a particle size of a certain size or less flow downstream along with the hot air (FIG. 1). On the other hand, the crushed particles larger than a certain size are not blown off by the hot air but fall again to the dry media assembly 3 and are further crushed between the media.

[0029] Thus, the hot air was blown to the downstream side.
The raw material powder particles 9 pass through the cyclone S,
It is collected as a raw material powder 10. Raw material powder 10 to be recovered
Means that the average particle diameter is, for example, 0.2 to 2.0 μm and the BET ratio
Surface area value is, for example, 3 to 12 m ²/ G.

In FIG. 1, the diameter of the drying medium 2 is
It is set appropriately according to the flow cross-sectional area of the hot air duct 4. If the diameter is insufficient, the impact force on the powder agglomeration layer formed on the medium is insufficient, and a raw material powder having a particle diameter within an intended range may not be obtained. On the other hand, if the diameter is too large, even if hot air is circulated, it is difficult for the dry medium 2 to move, so similarly the striking force is insufficient, and the raw material powder having the intended range of particle diameter may not be obtained. . Note that it is desirable to use a dry medium 2 having a uniform size as much as possible in order to form an appropriate gap between the media and promote the movement of the medium during hot air circulation.

The filling depth t1 of the drying medium 2 in the drying medium assembly 3 is appropriately set in accordance with the flow rate of the hot air within a range in which the flow of the medium 2 is sufficient and sufficient. If the filling depth t1 is too large, the flow of the dry medium 2 becomes difficult, and the impact force is insufficient, so that a raw material powder having a desired particle diameter may not be obtained. On the other hand, if the filling depth t1 is too small, the amount of the dry medium 2 is too small, and the frequency of impact is reduced, leading to a reduction in processing efficiency.

Next, the temperature of the hot air is appropriately set within a range in which the drying of the slurry proceeds sufficiently and no problems such as thermal deterioration of the powder occur. For example, when the solvent of the slurry is mainly water, when the temperature of the hot air is lower than 100 ° C., the supplied slurry does not sufficiently dry, and the water content of the obtained raw material powder becomes too high to cause agglomeration. In some cases, powder having the desired particle size cannot be obtained.

Further, the flow velocity of the hot air is appropriately set within a range in which the drying medium 3 is not blown to the collecting section 21. When the flow velocity is too low, the flow of the drying medium 2 becomes difficult, and the impact force is insufficient, so that a raw material powder having a particle diameter within an intended range may not be obtained. On the other hand, if the flow velocity is too high, the drying medium 2 rises too high and the collision frequency is rather reduced, leading to a reduction in processing efficiency.

The raw material powder 10 thus obtained is shown in FIG.
The sphere is formed by the rolling granulator 30 shown in FIG. As the tumbling granulation apparatus 30, a known one can be used. For example, a granulation vessel 3 having a somewhat flat cylindrical shape and an open upper side is used.
2, which is rotatably driven by a rotation drive unit (not shown) via a rotation shaft 32 having one end coupled to the center of the bottom surface of the bottom in a substantially orthogonal manner.

Then, the granulation container 32 is driven to rotate at a constant peripheral speed, and the raw material powder is supplied thereto together with water (for example, by spraying). As shown in FIG. 4 (b), the charged raw material powder P is supplied to the rotating granulation container 32.
Rolling on the inclined powder layer formed therein forms a compact G by spherical aggregation. The operating conditions of the tumbling granulator 30 are adjusted, for example, so that the diameter of the obtained compact G is 5 mm or less and the relative density is 61% or more. Specifically, the rotation speed of the granulation container 32 is 10 to 200 rpm
m, and the water supply amount is adjusted so that the water content in the finally obtained molded body is 10 to 20% by weight. The average particle diameter of the silicon nitride-based crystal particles constituting the compact G is, for example, in a range of 2.4 μm or less. If this formed body G is fired by the method described later, for example, the diameter is 4.5 m.
m or less can be obtained.

The molded body obtained as described above can be fired by two-stage firing of primary firing and secondary firing. The primary firing is performed at a temperature of 1900 ° C. or less in a non-oxidizing atmosphere containing nitrogen at 1 to 10 atm or less so that the density of the sintered body after the primary firing becomes 78% or more, preferably 90% or more. Is desirable. Primary firing density is 7
If it is less than 8%, many defects such as pores tend to remain after the secondary firing, which is not preferable. The secondary firing is performed in a non-oxidizing atmosphere containing nitrogen at 10 to 1000 atm.
It can be performed at 00 to 1950 ° C. The firing pressure is 1
If the pressure is less than 0 atm, the decomposition of silicon nitride cannot be suppressed, and even if the pressure exceeds 1000 atm, there is no change in the effect, and the cost is disadvantageous. On the other hand, when the firing temperature is lower than 1600 ° C., defects such as pores cannot be eliminated and the strength is reduced.
When the temperature exceeds ℃, it is difficult to reduce the average particle diameter to, for example, 2.4 μm or less due to the grain growth, and the strength of the sintered body is liable to decrease.

The thus-obtained spherical silicon nitride sintered body is selectively removed by a deformed spherical body sorting apparatus described below in which the above-described deformation amount Δd is determined to exceed 0.1 mm, for example. Is done. The remaining spherical silicon nitride-based sintered body is subjected to coarse polishing for size adjustment and then precisely polished using fixed abrasives to form a ceramic ball 43 shown in FIG. The average particle size of the ceramic balls 43 is, for example, 2.4.
It is adjusted within the range of μm or less. In addition, ceramic ball 4
The surface roughness of the polished surface of No. 3 is adjusted to, for example, 0.012 μm Ra (arithmetic average roughness) or less, and the cutoff value and the evaluation length at this time adopt the standard values in JIS B0601-1994.

For example, as shown in FIG. 5, a ball bearing 40 can be obtained by incorporating a ceramic ball 43 between an inner ring 42 and an outer ring 41 made of metal or ceramic. The shaft SH is provided on the inner surface of the inner ring 42 of the ball bearing 40.
Is fixed, the ceramic ball 43 is held rotatably or slidably with respect to the outer ring 41 or the inner ring 42.

FIGS. 6 to 8 show an example of an apparatus for sorting deformed spherical bodies as one embodiment of the apparatus for sorting spherical bodies according to the present invention. The sorting device 50 for irregularly shaped spheres includes a spiral tube 51 (spiral long hollow member; inclined path) made of transparent or translucent polyurethane and having a circular cross section.
1, a supply unit 52 and a measurement unit 5
3, display unit 54, sorting unit 55, adjusting unit 56, and discharging unit 5
7 is provided. The spiral tube 51 has a running section 51A, a measurement section 51B, and a deceleration section 51 in order from the top.
C is formed, and the central axis of the measurement section 51B is inclined downward by an inclination angle θ with respect to the horizontal line. The central axes of the approach section 51A and the deceleration section 51C are substantially horizontal or inclined downward at an angle smaller than the inclination angle θ.

The practical range of the inclination angle θ is 0.5 ≦ θ.
≤4 ° is desirable. By setting the inclination angle θ in this range, the difference in the required drop time of the measurement section 51B in the helical tube 51 is determined by the sphericity (for example, the deformation Δ
Since it is formed sufficiently and stably in accordance with d), it is easy to measure the time required for dropping and to sort out deformed spherical bodies (rejected products).

The spiral tube 51 is transparent or translucent so that the supply work W0 can be easily found when clogged halfway. Further, since the material of the spiral tube 51 is made of polyurethane, the workability is good, the supply work W0 is easily rolled, and the supply work W0 is not easily worn by rolling. The spiral tube 51
May have a non-circular cross section. Further, as described above, the rolling resistance is affected by (the size of) the unevenness existing on the contact surface between the supply work W0 and the tube 51, so that the deformed work W 'is formed.
The inner surface of the tube 51 has a surface roughness of 20 μm
It is desirable to keep it below (maximum height). However, the reference length and the evaluation length at this time are based on JIS B0601.
-Use the standard value in 1994. In addition, the main dimensions of the spiral tube 51 are as follows. -Measurement section length of tube 51 (length of 51B): L = 2
000-4000 mm ・ Rotating diameter of tube 51: D = 100-200 mm ・ Inner diameter of tube 51: D1 = 2-10 mm ・ Outer diameter of tube 51: D2 = 5-13 mm

The supply section 52 is provided with a supply gutter 521 for accommodating a supply work W0 (sorted object) of a spherical silicon nitride sintered body facing the supply port 511 of the run-up section 51A of the spiral tube 51. Have been. A transmissive photoelectric sensor 522 for detecting the presence or absence of the supply work W0 is provided in the approaching section 51A.
When the photoelectric sensor 522 does not detect the presence of the supply work W0, the pump 523 is driven, and the supply cylinder 524 sends the next supply work W0 to the supply port 511. In the measurement section 51B following the approach section 51A,
A measurement unit 53 is provided. Transmission-type photoelectric sensors 531 and 532 are installed on the entrance side and the exit side of the measurement section 51B, respectively. When the supply work W0 interrupts the transmitted light of the entrance-side photoelectric sensor 531, the timer 533 starts time measurement, and The timer 533 is set to stop counting when W0 blocks the transmitted light from the exit-side photoelectric sensor 532. That is, the distance between the two photoelectric sensors 531 and 532 is the measurement section 51B (predetermined section), and the timer 5
The display 33 indicates the time required for dropping the supply work W0 (sorted object).

Next, the sorting device 50 is provided with a display unit 54 and a sorting unit 55 in association with the measuring unit 53. The display unit 54 includes an acoustic buzzer 541 and a voice synthesis speaker 54.
2. Arbitrary notification means such as a colored display lamp 543 and a liquid crystal display 544 are provided. Further, in the deceleration section 51C of the spiral tube 51, a selection gutter 552 that is opened and closed radially outward of the tube 51 by cutting out a part of the lower surface of the tube 51, and a selection gutter that opens and closes the selection gutter 552. A sorting unit 55 including a drive motor 551 is attached. And the supply work W0 (sorted body)
When the time required for falling exceeds a value (predetermined value) determined by a preliminary experiment or the like, the supply work W0 is deformed by an amount Δ
Sorted as rejected products with large d, and notified means 541-5
Notify by 44 etc. At the same time, the motor 551
Is driven to open the sorting gutter 552, and the corresponding work is accommodated in the rejected product box 553 as a deformed work W ′. On the other hand, if the time required for dropping the supply work W0 is within a predetermined value, the notification means 541 to 544 and the like are not operated, and the sorting gutter 5 is not operated.
The work 52 is closed, and the corresponding work is accommodated in the accepted product box 554 through the discharge port 512 of the spiral tube 51 as a compatible work W.

Further, the sorting device 50 is provided with an adjusting section 56 and a discharging section 57. An adjusting gear drive motor 561 for adjusting the inclination angle θ of the selection device 50;
An adjusting portion 56 composed of an inclination angle adjusting gear 562 integrally connected to 61 is fixed to a fixing portion (not shown), and a driven gear 563 fixed to an arbitrary position of the sorting device 50 is an adjusting gear 562.
And are engaged. Supply port 5 of spiral tube 51
The outlet of the air nozzle 572 of the discharge unit 57 faces the 11. The supply work W0 is a spiral tube 51
When jammed inside, the compressed air supplied from the air compressor 571 is blown out from the air nozzle 572, and the sorting gutter 552 is opened, and the clogged work is discharged from the sorting gutter 552 and stored in the rejected product box 553. .

FIG. 8 shows the supply work W0 and the spiral tube 5
1 shows a cross section. The cross-sectional area of the hollow part of the tube 51 is S
1. When the sectional area of the supply work W0 having the outer diameter d is S2,
The area ratio S1 / S2 = (D1 / d) ² is 1 <S1 / S2 ≦ 1
5 is desirable. By setting the area ratio in this range, the surface of the supply work W0 comes into wide contact with the inner surface of the tube 51, so that the rolling resistance (rolling friction force) acts on a wide range of the surface of the supply work W0. Thus, a speed difference is generated when the spiral tube 51 rolls and falls on the measurement section 51B. The spiral tube 51 has a cross-sectional dimension (inner diameter) D1 larger than the diameter d of the supply work W0.

FIG. 9 is a block diagram showing an electrical configuration of the sorting apparatus shown in FIG. The control unit 58 includes an I / O port 58
1 and the CPU 582, ROM 583, R
A control program 583a is stored in the ROM 583. Then, the photoelectric sensor 522 of the supply unit 52
The output of the timer 533 operated by the photoelectric sensors 531 and 532 of the measurement unit 53 is output from the I / O port 58.
1 has been entered. On the other hand, the I / O port 581
The drive units of the supply unit 52, the display unit 54, the selection unit 55, the adjustment unit 56, and the discharge unit 57 are connected.

The driving section of the supply section 52 includes a servo drive unit 520 and a supply cylinder 5 connected to the unit 520.
24, etc. The driving unit of the display unit 54 includes a driving circuit 540 and a circuit 5
A sound buzzer 541, a voice synthesis speaker 542, a colored display lamp 543, a notification unit such as a liquid crystal display 544, and the like connected to the control unit 40 are configured. The drive unit of the selection unit 55 includes a servo drive unit 550 and a selection gutter drive motor 55 connected to the unit 550 and driving the selection gutter 552.
1 and the like. The driving unit of the adjusting unit 56
It includes a servo drive unit 560 and an adjustment gear drive motor 561 connected to the unit 560 to drive the tilt angle adjustment gear 562. The drive unit of the discharge unit 57 includes a servo drive unit 570 and an air compressor 5 connected to the unit 570 and driving the air nozzle 572.
71 and the like.

Here, an outline of the operation of the sorting apparatus of FIG. 6 will be described with reference to FIG. First, the value of the required time T for dropping the supply work W0 and the value of the inclination angle θ of the spiral tube 51 set by preliminary experiments and the like are stored in the RAM 584 of the control unit 58.
To memorize. At this time, the adjusting gear drive motor 561 is rotated until the inclination of the spiral tube 51 matches the stored inclination angle θ. When the photoelectric sensor 522 does not detect the presence of the supply work W0, the pump 523 is driven to move the supply cylinder 524, and the supply work W0 is sent from the supply gutter 521 to the supply port 511. Supply work W0
Indicates that the speed gradually increases in the approach section 51A and the measurement section 51
Rolling down while accelerating further at B, deceleration section 51C
To reduce the speed again. At this time, the timer 533 measures the time required to fall from when the supply work W0 blocks the transmitted light of the entrance-side photoelectric sensor 531 to when it blocks the transmitted light of the exit-side photoelectric sensor 532.

If the time measured by the timer 533 is within the required dropping time T stored therein, the supply work W0 passes through the discharge port 512 of the spiral tube 51 as a compatible work W, and is stored in the accepted product box 554. You. On the other hand, when the measurement time exceeds the required dropping time T, it is selected as a rejected product, and is notified by the notification means 541 to 544 and the like, and the motor 551 is driven to open the selection gutter 552 to obtain the deformed work W ′. It is stored in the rejected product box 553. The continuous operation is performed by repeating the above operations. Further, when the measurement time far exceeds the required drop time T, it is determined that the supply work W0 is clogged in the spiral tube 51, the continuous operation is stopped, the compressed air is ejected from the air nozzle 572, and the sorting gutter 552 is formed. And the clogged work is discharged from the sorting gutter 552, and the rejected product box 553 is released.
Housed in

The supply work W0 is fed into the supply port 511 after the time of the supply work W0 immediately before is finished and the sorting into the conforming work W or the deformed work W 'is completed, and is processed one by one. It shall be. In order to improve the sorting efficiency, a plurality of sorting devices 50 may be provided in parallel. By the way, when the photoelectric sensor 522 no longer detects the presence of the supply work W0, the supply work W0 is continuously sent to the supply port 511 before the selection of the supply work W0 immediately before is completed. The efficiency of measurement can be improved and the automation of sorting can be promoted. In addition, if the timekeeping data of the supply work W0 is accumulated in the RAM 584 and the setting of the required drop time T and the inclination angle θ is automatically corrected in accordance with the result of the data analysis, more accurate sorting / sorting can be performed. Will be possible.

Instead of the photoelectric sensors 522, 531 and 532, another non-contact sensor such as an ultrasonic sensor, an infrared sensor, a proximity switch or the like may be used, or a limit switch may be used. A drive motor may be used instead of the pump 523, and a pump may be used instead of the drive motors 551 and 561. When a pump is used, it does not matter whether it is a pneumatic type or a hydraulic type. Other than the sound buzzer 541, the voice synthesis speaker 542, the coloring display lamp 543, and the liquid crystal display 544 can be used as the notification means. Sorting unit 55
Instead of the structure in which the selection gutter 552 is opened and closed by the selection gutter drive motor 551, the deformed work W ′ may be stored in the rejected product box 553 by compressed air ejected from an air nozzle.

FIG. 10 shows a modified example of the apparatus for sorting deformed spherical bodies. In the sorting device 60, an inclined shooter 61 (inclined path) having a semicircular cross section is provided instead of the spiral tube 51 of FIG. A running section 61A, a measurement section 61B, and a deceleration section 61C are formed in the inclined shooter 61 in order from the top, and the central axis of the measurement section 61B is inclined downward by an inclination angle θ with respect to a horizontal line. The central axes of the approach section 61A and the deceleration section 61C are substantially horizontal or inclined downward at an angle smaller than the inclination angle θ.

FIG. 11A shows a cross section of the inclined shooter 61 perpendicular to the axis. The bottom portion 61a of the inclined shooter 61 is formed in a semi-arc shape, and extension portions 61b that rise vertically and linearly are continuously provided at both ends of the arc shape. Extension 61
b has the following two roles. It has a role of preventing the supply work W0 from jumping out and falling from the inclined shooter 61, and a role of forming a speed difference when the supply work W0 rolls down the measurement section 61B of the inclined shooter 61. Regarding the latter role, specifically, the surface of the supply work W0 is the bottom portion 61a of the inclined shooter 61.
Is in contact with the inner surface of the extension 61b as well as the inner surface of the extension 61b, so that the rolling resistance (rolling frictional force) acts on a wide range of the surface of the supply work W0, and the deformation amount Δd
Accordingly, a speed difference when rolling and falling down the measurement section 61B is formed.

In the case of FIG. 11A, in the section perpendicular to the axis of the shooter 61, the area of a portion surrounded by a virtual connection line 61c connecting the bottom surface 61a, the inner surface of the extension 61b and the upper end of the extension 61b is S1 '. When the sectional area of the supply work W0 is S2, the provisional area ratio is given by S1 '/ S2.

The cross section of the inclined shooter 61 perpendicular to the axis may be non-circular. FIGS. 11B and 11C show other examples of the cross-section orthogonal to the axis. In each embodiment of FIG. 11, the inclined shooter 61 has a cross-sectional dimension L larger than the diameter d of the supply work W0. In FIG. 10, the same parts as those in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted. Since the inclined shooter 61 is open at the upper side so that the supply work W0 can be easily removed when the work W0 is clogged, the discharge section 57 in FIG. 6 is not sufficient.

[0056]

[Experimental Examples] In order to confirm the effects of the present invention, the following experiments were conducted. As the supply work W0, spherical silicon nitride sintered bodies produced by the rolling granulation method of FIG. 4 and having different deformation amounts Δd were prepared. The outer diameter of the supply work W0 (spherical silicon nitride sintered body) varied from 2.7 to 2.8 mm, and the average outer diameter d of the work was 2.75 mm. Such a supply work W0 was put into the sorting apparatus shown in FIG. 6 to measure the required time T for dropping, and the amount of deformation Δd was measured using a micrometer. Note that the inclination angle θ was adjusted in the range of 1 to 6 °.

The main dimensions of the sorting device used at this time are:
The following is a description with reference to FIGS. 7 and 8. -Measurement section length of tube 51 (length of 51B): L = 3
000 mm ・ Rotating diameter of tube 51: D = 150 mm ・ Inner diameter of tube 51: D1 = 5 mm ・ Outer diameter of tube 51: D2 = 8 mm ・ Average outer diameter of supply work W0: d = 2.75 mm ・ Area ratio: S1 / S2 = (D1 / d) ² = 3.30

Then, when the difference Δd between the deformation amount Δd is 0.1 mm or less and when it exceeds 0.1 mm, the difference of the required drop time T is 1 sec or more, ○, and when it is less than 1 sec, x is evaluated. Was. Table 1 shows the results of the above experiments.

[0059]

[Table 1]

In Table 1, when the inclination angle θ is 4 °, the required time T for dropping the supply work W0 having the deformation amount Δd of 0.1 mm or less is 8.3 sec, and the deformation amount Δd is more than 0.1 mm.
The required drop time T of the supply work W0 of 2 mm or less is 9.9.
sec. Since the time difference between the two is 1 sec or more, T = 9.9 sec (preferably 8.5 sec to 9.
By measuring the time required for falling with 5 sec) as a boundary value, it is possible to sort out deformed spheres. Similar conclusions are drawn when the inclination angle θ is 2 ° and 1 °.

However, when the inclination angle θ is 6 °, the required time T for dropping the supply work W0 having the deformation amount Δd of 0.1 mm or less is 6.3 sec, and the deformation amount Δd is more than 0.1 mm 0.2
The required drop time T of the supply work W0 of 5.9 mm or less is 5.9 s
ec, and the time difference between the two was less than 1 sec. In consideration of the tolerance and the like, it is considered difficult to select the deformed spherical bodies by measuring the time required for dropping.

The rolling granulation method shown in FIG. 4 has the advantage that it can be manufactured at a lower cost than the pressure molding method or the like. However, the deformation amount Δd of the manufactured spherical silicon nitride sintered body is relatively large. Outer diameter d
Tend to be irregular. Therefore, the method and apparatus for sorting spherical bodies according to the present invention are particularly effective for spherical silicon nitride-based sintered bodies manufactured by the rolling granulation method, but the present invention is based on the rolling granulation method. It is not limited to the manufactured spherical body. Further, the object to be sorted according to the present invention is not limited to ceramic balls such as spherical silicon nitride sintered bodies.

Further, with respect to the method and the apparatus for sorting spherical bodies according to the present invention, only the embodiment in the case where the sorted bodies are sorted into either acceptable products or unacceptable products according to the time required for dropping has been described. Sorted into three or more ranks,
You may make it use a spherical body according to each rank.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view conceptually showing an example of an apparatus for producing a raw material powder for ceramic balls.

FIG. 2 is a diagram for explaining the operation of the apparatus shown in FIG. 1;

FIG. 3 is an operation explanatory view following FIG. 2;

FIG. 4 is a perspective view and an operation explanatory view of a rolling granulator.

FIG. 5 is a schematic view of a ball bearing using ceramic balls.

FIG. 6 is a perspective view of an apparatus for sorting deformed spherical bodies according to an embodiment of the present invention.

FIG. 7 is a front view and a plan view of FIG. 6;

FIG. 8 is an axial cross-sectional view of a spiral tube.

FIG. 9 is a block diagram showing an electrical configuration of the sorting device shown in FIG. 6;

FIG. 10 is a side view showing a modification of the sorting device of FIG. 6;

FIG. 11 is a cross-sectional view perpendicular to the axis of the inclined shooter.

FIG. 12 is an explanatory view of a spherical body that rolls and falls on an inclined path.

[Explanation of symbols]

Reference Signs List 50 Sorting device 51 Spiral tube (spiral long hollow member; inclined path) 53 Measurement unit 54 Display unit 55 Sorting unit 61 Inclined shooter (inclined path) W0 Supply work (sorted object) W Compatible work (accepted product) W '' Irregular work (rejected product) T Time required for falling θ Tilt angle

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Tomoki Niwa 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi, Aichi F-term (reference) 2F062 AA57 BB09 BC38 CC22 CC23 CC27 EE01 EE31 FF13 FF18 FF22 GG72 GG90 LL11 LL17 MM13 MM15 NN02 3J101 AA02 EA01 EA41 FA44 GA53 GA55 4D021 JA09 JB01 KA08 KA12 KB10 LA04 MA01 MA08 NA10

Claims (8)

[Claims] 1. A time required for a spherical object to be rolled down and passed through a predetermined section of an inclined path (hereinafter, referred to as a time required for dropping) is measured, and the object to be sorted is determined in accordance with the time required for dropping. A method for sorting spherical bodies, characterized by sorting. 2. The method for sorting spherical bodies according to claim 1, wherein the sorted bodies are sorted into either acceptable products or unacceptable products according to the time required for dropping. 3. The method for sorting spherical bodies according to claim 1, wherein the inclined path has a cross-sectional dimension larger than the diameter of the sorted body and is formed of a helical long hollow member. 4. The method according to claim 3, wherein the elongated hollow member is transparent or translucent. 5. The hollow section of the long hollow member has a sectional area of S
1. When the sectional area of the object to be sorted is S2, the area ratio S1
5. The method for sorting spherical bodies according to claim 3, wherein / S2 satisfies 1 <S1 / S2≤15. 6. The method for sorting spherical bodies according to claim 1, wherein 0.5 ≦ θ ≦ 4 ° is satisfied, where θ is an inclination angle formed by the inclined path with respect to a horizontal line. 7. A sloping path for rolling and dropping a spherical object to be sorted, a measuring unit for measuring a time required to pass through a predetermined section of the sloping path (hereinafter referred to as a required time for dropping), A sorting unit for sorting the object to be sorted in accordance with the selected object. 8. For each of the plurality of spherically shaped objects to be sorted, they are rolled and dropped on an inclined path, and the time required for passing through a predetermined section of the inclined path (hereinafter referred to as a required drop time) is measured. A method for producing a spherical body, wherein the plurality of objects to be sorted are sorted according to the required time for dropping.