Ceramic sphere inspection apparatus and ceramic sphere inspection method using the same

Abstract

To provide a ceramic spherical body inspection device capable of eliminating a mistake of re-inspecting a ceramic spherical body determined to be non-defective.SOLUTION: A ceramic sphere inspection apparatus according to an embodiment is a ceramic sphere inspection apparatus for inspecting an outer diameter of a ceramic sphere, wherein an arranging member for arranging the ceramic sphere has a first arranging section and a second arranging section, and the ceramic sphere inspection apparatus has a mechanism for arranging the ceramic sphere in the first arranging section and accommodating the ceramic sphere determined to be a non-defective product in the second arranging section after completion of inspection. Further, it is preferable that the arrangement member has a plurality of first arrangement portions and a plurality of second arrangement portions, and the number of the first arrangement members is the same as the number of the second arrangement members.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The embodiments described below relate to a ceramic sphere inspection device and a ceramic sphere inspection method using the same. [Background technology]

[0002] Ceramic sintered bodies are used in bearing balls. For example, Japanese Patent No. 5487099 (Patent Document 1) discloses bearing balls made of silicon nitride sintered bodies with a diameter of 20 mm or more. In Patent Document 1, the aspect ratio of silicon nitride crystal grains is controlled to suppress variations in Vickers hardness. The bearing balls in Patent Document 1 exhibited excellent durability even when they were large, with a diameter of 20 mm or more. Ceramic spheres made of sintered ceramics are manufactured using processes such as mixing raw material powders, molding, degreasing, and sintering. The molding process involves methods such as die molding and rolling granulation. For example, die molding forms a band-shaped portion on the circumference of the sphere. International Publication No. WO2023 / 190467 (Patent Document 2) discloses a ceramic sphere with a band-shaped portion. In Patent Document 2, the surface roughness of the band-shaped portion and the spherical surface is controlled to match the size of the band-shaped portion of the ceramic sphere before polishing. The ceramic sphere with the band-shaped portion is polished to form a bearing ball. The ceramic sphere before polishing is sometimes called a bare sphere. The shape of the raw sphere is inspected. For example, in Japanese Patent Laid-Open No. 2000-292138 (Patent Document 3), the shape is inspected using a CCD camera. Also, in Japanese Patent Laid-Open No. 2003-294642 (Patent Document 4), the shape is inspected using a line sensor while a ceramic sphere is rolled on two rollers. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5487099 [Patent Document 2] International Publication No. WO2023 / 190467 [Patent Document 3] Japanese Patent Application Laid-Open No. 2000-292138 [Patent Document 4] Japanese Patent Application Laid-Open No. 2003-294642 Summary of the Invention [Problem to be solved by the invention]

[0004] The inspection method of Patent Document 3 is effective for shape inspection. However, since the ceramic spheres remain in the same location even after the pass / fail judgment, it is not possible to judge whether they are before the inspection or after the inspection is completed. This has led to problems such as having to re-inspect the items after the inspection is completed. Furthermore, in Patent Documents 3 and 4, the ceramic sphere is inspected while being rotated or rolled, which makes it unsuitable for inspecting a ceramic sphere having a band-shaped portion. The embodiment is intended to address such issues and provides a ceramic sphere inspection device that makes it possible to prevent erroneous judgments before and after inspection is completed. [Means for solving the problem]

[0005] The ceramic sphere inspection device of the embodiment is a ceramic sphere inspection device that inspects the outer diameter of a ceramic sphere, and is characterized in that the placement member for placing the ceramic sphere has a first placement section and a second placement section, and the ceramic sphere is placed in the first placement section, and after inspection is completed, ceramic spheres that are determined to be good products are placed in the second placement section. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a conceptual diagram showing an example of a ceramic sphere inspection device according to an embodiment. [Figure 2] FIG. 10 is a diagram showing an example of an arrangement member according to the embodiment. [Figure 3]FIG. 10 is a diagram showing an example in which ceramic spheres having strip-shaped portions are arranged on an arrangement member according to an embodiment. [Figure 4] FIG. 1 shows an example of a ceramic sphere having a band-shaped portion. [Figure 5] FIG. 1 shows an example of a ceramic sphere without bands. DETAILED DESCRIPTION OF THE INVENTION

[0007] The ceramic sphere inspection device according to the embodiment is a ceramic sphere inspection device that inspects the outer diameter of a ceramic sphere, the arrangement member for arranging the ceramic spheres has a first arrangement portion and a second arrangement portion; placing ceramic spheres in a first placement portion; The device is characterized by having a mechanism in which, after the inspection, ceramic spheres that are determined to be non-defective are placed in the second placement section. Figure 1 shows a conceptual diagram of a ceramic sphere inspection device according to an embodiment. Figures 2 and 3 show an example of an arrangement member. In the figures, reference numeral 1 denotes a ceramic sphere inspection device, reference numeral 2 denotes an arrangement member, reference numeral 3 denotes a first arrangement section, reference numeral 4 denotes a second arrangement section, and reference numeral 5 denotes a ceramic sphere. Figures 4 and 5 show an example of a ceramic sphere. In the figures, reference numeral 5 denotes a ceramic sphere, reference numeral 6 denotes a spherical section, and reference numeral 7 denotes a strip-shaped section. The ceramic sphere inspection device is sometimes simply referred to as an inspection device.

[0008] The ceramic sphere inspection device according to the embodiment is a ceramic sphere inspection device that inspects the outer diameter of a ceramic sphere, the arrangement member for arranging the ceramic spheres has a first arrangement portion and a second arrangement portion; placing ceramic spheres in a first placement portion; The device is characterized by having a mechanism in which, after the inspection, ceramic spheres that are determined to be non-defective are placed in the second placement section.

[0009] The ceramic sphere 5 has a spherical surface 6. The ceramic sphere 5 may have a band-shaped portion 7 or may not have a band-shaped portion 7. As shown in FIG. 4, the band-shaped portion 7 is formed on the circumference of the spherical surface 6. The band-shaped portion 7 is formed when die molding is used. FIG. 5 shows a ceramic sphere 5 without a band-shaped portion 7. Examples of ceramic spheres 5 without a band-shaped portion 7 include those produced by rolling granulation. Examples include those produced by removing the band-shaped portion from a molded body produced by die molding and then sintering. Alternatively, the ceramic sphere 5 (ceramic sintered body) with the band-shaped portion 7 may be one in which the band-shaped portion has been removed.

[0010] The ceramic sphere inspection device according to the embodiment is a ceramic sphere inspection device that measures the outer diameter of a ceramic sphere. The outer diameter refers to the diameter. One or both of the diameter of the spherical portion and the diameter of the band-shaped portion may be measured. The diameter of a single ceramic sphere may also be measured multiple times. The outer diameter can be measured using image inspection or laser inspection. Image inspection can be performed using a CCD camera, area sensor, line sensor, etc. Image inspection equipment is sometimes called an image dimension measuring instrument.

[0011] The outer diameter of the ceramic sphere is measured and judged to be good or bad according to the size of the ceramic sphere. The diameter range that is considered to be good is determined in advance according to the size of the ceramic sphere. In addition, for ceramic spheres with a band-like portion, it is preferable to determine the diameter range that is considered to be good for the area with and without the band-like portion. Furthermore, the ceramic sphere inspection device 1 has a placement member 2 for placing ceramic spheres 5, which has a first placement section 3 and a second placement section 4. The first placement section 3 and the second placement section 4 have recessed and uneven shapes for placing the ceramic spheres 5. It is also preferable that the first placement sections 3 and the second placement sections 4 have the same number. Figure 2 shows a placement member 2 provided with three first placement sections 3 and three second placement sections 4. It is sufficient that there be one or more pairs of first placement sections 3 and second placement sections 4. Furthermore, when comparing the outer diameter of the ceramic sphere 1 with the outer diameter of the first arrangement portion 3, it is preferable that the outer diameter of the ceramic sphere 1 > the outer diameter of the first arrangement portion 3. In the case of a recess, the outer diameter of the first arrangement portion 3 is the maximum diameter of the recess. For example, if the recess is circular, the largest diameter is the outer diameter of the first arrangement portion 3. Also, if the recess is square, the largest diagonal is the outer diameter of the first arrangement portion 3. The size of the first arrangement portion 3 is arbitrary. It may be either the outer diameter of the ceramic sphere 1 > the outer diameter of the first arrangement portion 3, the outer diameter of the ceramic sphere 1 = the outer diameter of the first arrangement portion 3, or the outer diameter of the ceramic sphere 1 < the outer diameter of the first arrangement portion 3. On the other hand, if the outer diameter of the ceramic sphere 1 > the outer diameter of the first arrangement portion 3, a structure can be created in which the spherical portion 6 of the ceramic sphere 1 is placed on the outer diameter of the first arrangement portion 3. This allows for stable arrangement even if the size of the ceramic sphere 1 changes. For this reason, it is preferable that the outer diameter of the ceramic sphere 1 > the outer diameter of the first arrangement portion 3. This is particularly effective when the outer diameter of the ceramic sphere is 20 mm or more. Furthermore, it is preferable that the placement member 2 is transparent, which makes it easier to inspect using an image inspection device. Examples of transparent materials include plastic.

[0012] First, a process of placing ceramic spheres 5 in the first placement unit 3 is performed. Next, after the inspection is completed, a mechanism is provided to place ceramic spheres 5 determined to be non-defective in the second placement unit 4. In other words, the placement location of the ceramic spheres 5 changes before and after the inspection. This eliminates the risk of re-inspection. In conventional inspection devices, the placement location of the ceramic spheres 5 does not change even after the inspection. This leads to the error of re-inspecting a ceramic sphere 5 that has already been inspected. Furthermore, there is a problem in that it is difficult to tell whether the placed ceramic sphere 5 has been inspected or not. The inspection device according to the embodiment changes the placement location of the ceramic spheres 5 before and after the inspection, eliminating such errors. Furthermore, by providing a mechanism that displays an error message or sounds a warning sound when a ceramic sphere 5 is placed in the second placement unit 4 before the inspection, errors can be further reduced. The placement member 2 with the ceramic spheres 5 placed in the first placement unit 3 is moved to the image inspection device side, and after the inspection is completed, the placement member 2 is returned to its original position. At that time, those judged to be non-defective are moved to the second placement unit 4.

[0013] The ceramic spheres may also have strip-shaped portions. When using an arrangement member 2 having multiple first arrangement sections 3 and second arrangement sections 4, it is preferable to align the orientation of the strips of the ceramic spheres 5 having strip-shaped portions 7 in the multiple first arrangement sections 3. It is also preferable to align the orientation of the strips within a range of ±20°. Figure 3 shows an example in which the orientation of the strip-shaped portions 7 is aligned at 90°. For example, when aligning the strip-shaped portions 7 at 90°, it is preferable to align the orientation of the strip-shaped portions 7 within a range of 90° ±20°. Aligning the orientation of the strip-shaped portions 7 can improve the accuracy of measuring the outer diameter. Furthermore, the outer diameter of each ceramic sphere is measured multiple times. In particular, when a ceramic sphere has a strip-shaped portion, it is necessary to measure the outer diameter in both locations with and without the strip-shaped portion. Aligning the orientation of the strip-shaped portions 7 makes it easier to determine the location of the strip-shaped portion. 3 shows an example in which the strip portions 7 are aligned at 90°, but the direction of the strip portions can be any direction as long as they are aligned. The strip portions may also be aligned at 45° or 0° (horizontal).

[0014] It is also preferable to have a mechanism for moving ceramic spheres determined to be defective from the first placement section to a defective product storage container. In the ceramic sphere inspection device according to the embodiment, those determined to be non-defective are moved to the second placement section. By providing a mechanism for moving those determined to be defective to a defective product storage container, the problem of having to re-inspect defective products can be eliminated. Furthermore, by automating the mechanism for moving defective products to a defective product storage container, the problem of having to re-inspect defective products can be reduced to zero. Another example of automation is the use of robots. It is also preferable to have a mechanism for transferring ceramic spheres determined to be non-defective from the second placement section to a non-defective product storage container. By automating the mechanism for transferring non-defective products to the non-defective product storage container, inspection efficiency can be improved.

[0015] It is also preferable to automate the mechanism for placing the ceramic spheres 5 before inspection in the first placement section 3. By automating one or more of the steps of placing the ceramic spheres 5 before inspection in the first placement section 3, moving non-defective products to a non-defective product storage container, and moving defective products to a defective product storage container, inspection efficiency can be improved. For this reason, it is most preferable to automate all three steps. Examples of the automated robot include a robot arm and a belt conveyor. Examples of the robot arm include a single-axis robot. The process of placing the pre-inspection ceramic spheres 5 in the first placement section 3, the process of moving the non-defective products to a container for storing non-defective products, and the process of moving the defective products to a container for storing defective products can all be performed by humans, but by automating these processes, inspection efficiency can be improved.

[0016] Additionally, the outer diameter of the ceramic sphere is preferably 9 mm or greater. Ceramic bearing balls are available in sizes 2 mm or greater. For example, diameters vary, including 6.3500 mm (1 / 4 inch), 9.5250 mm (3 / 8 inch), 15.8750 mm (5 / 8 inch), 28.5750 mm (1 1 / 8 inch), 30.1625 mm (1 3 / 16 inch), 36.5125 mm (1 7 / 16 inch), 44.4500 mm (1 3 / 4 inch), and 63.5000 mm (2 1 / 2 inch). These sizes are the sizes of finished bearing balls. Finished balls are ceramic bearing balls that have been polished. Bearing balls before polishing are sometimes called raw balls. Raw balls are ceramic spheres 5. Larger ceramic spheres 5 are often produced by molding. When molded, ceramic spheres are formed with a band. Typically, the larger the ceramic sphere, the larger the band. Therefore, the larger the size of the sphere, the more important it is to inspect the outer diameter.

[0017] Furthermore, the larger the ceramic sphere, the easier it is to transport it using a robot arm. Methods for transporting it using a robot arm include clamping it with the arm or using suction. Larger ceramic spheres have larger spherical surfaces, making them easier to transport by suction. Therefore, the outer diameter of the ceramic sphere is preferably 9 mm or more, and even 20 mm or more. The upper limit of the outer diameter of the ceramic sphere is preferably 100 mm or less. If the outer diameter exceeds 100 mm, it may be difficult to produce a ceramic sintered body. Therefore, the outer diameter of the ceramic sphere is preferably within the range of 9 mm to 100 mm, and even more preferably 20 mm to 70 mm.

[0018] The ceramic spheres are made of a ceramic sintered body. The ceramic sintered body is preferably one selected from a silicon nitride sintered body, an aluminum oxide sintered body, and a zirconium oxide sintered body. The silicon nitride sintered body contains silicon nitride as the majority component. The aluminum oxide sintered body contains aluminum oxide as the majority component. The zirconium oxide sintered body contains zirconium oxide as the majority component. The component that is contained in the majority component is called the base material.

[0019] The production of a ceramic sintered body involves a raw material mixing step, a molding step, a degreasing step, and a sintering step. The raw material mixing process is a process for preparing a mixed raw material powder by mixing a base material and a sintering aid. If necessary, a binder or the like is added to the mixed raw material powder. The molding process uses methods such as die molding and rolling granulation. Die molding uses a die with a spherical inner surface. The mixed raw material powder is filled into the die and pressed with upper and lower dies to form the product. Rolling granulation is a method in which a mass of mixed raw material powder is made to serve as the core, and the core is rolled while being granulated. The resulting compact is then subjected to CIP (cold isostatic pressing) as required. The debinding step is a step in which the compact is heated to remove binders, etc. The debinding step is preferably carried out at a temperature in the range of 400°C or higher and 700°C or lower. The obtained degreased body is subjected to a sintering process. The sintering process is preferably carried out at a temperature in the range of 1600°C to 2000°C. Examples of the sintering process include atmospheric sintering, pressure sintering, and HIP (hot isostatic pressing). It is also possible to combine these sintering methods. The above steps allow for the production of ceramic spheres. When molded, ceramic spheres with band-like portions are obtained.

[0020] (Example) (Examples 1 to 3, Comparative Example 1) Ceramic spheres were prepared using sintered silicon nitride. These ceramic spheres were used as raw spheres before being polished to form bearing balls. The size of the ceramic spheres was recorded as the size of the bearing balls obtained by polishing. The sizes of the ceramic spheres are as shown in Table 1. Ceramic sphere E was produced by removing the band-shaped portion from a ceramic compact that had one, and then sintering it.

[0021] [Table 1]

[0022] Next, a placement member was prepared. The structure of the placement member is as shown in Table 2. In the examples and comparative examples, the outer diameter of the ceramic sphere 1 was greater than the outer diameter of the first placement portion 3. In the examples and comparative examples, transparent placement members were used.

[0023] [Table 2]

[0024] Example 1 is a set of a first arrangement portion and a second arrangement portion. Examples 2 to 7 are two to four sets of a first arrangement portion and a second arrangement portion. Comparative Example 1 is a structure with only a first arrangement portion.

[0025] Next, ceramic spheres were placed in the first placement section and image inspection was performed. In the example, a mechanism was provided to move those judged to be good products to the second placement section after inspection. In the example, a mechanism was provided to move those judged to be defective products to a defective product storage container. In addition, in Comparative Example 1, the ceramic spheres were left placed in the first placement section after inspection. Using the ceramic sphere inspection devices of the example and comparative example, the outer diameters of 100 ceramic spheres were inspected. The process of placing the ceramic spheres in the first placement section and the process of transferring the ceramic spheres judged to be non-defective to a non-defective product storage container were performed manually. The presence or absence of mistakes in re-inspecting products that were judged to be good products was measured. The inspection time for the Examples was also shown relative to the inspection time for Comparative Example 1, which was set at 100. The smaller the figure for the relative inspection time, the shorter the inspection time. The same image inspection device was used for both the Examples and the Comparative Examples. The results are shown in Table 3.

[0026] [Table 3]

[0027] As can be seen from the table, in the examples, products judged to be good were moved to the second placement section, so there was no mistake in re-inspecting products that had been judged to be good. Furthermore, in the examples, only products judged to be good could be moved to the good product storage container, so the inspection time could be shortened. In addition, in example 6, the direction of the band-shaped parts was randomly arranged at ±40°, so the inspection time was slightly longer. It was found that inspection efficiency could be improved by aligning the direction of the band-shaped parts. Furthermore, in example 7, the inspection time was slightly shorter because the ceramic spheres without band-shaped parts were inspected. In addition, the embodiment further shortened the inspection time by automating one or more of the following processes: placing ceramic spheres in the first placement section, transferring those determined to be non-defective from the second placement section to a non-defective product storage container, and transferring defective products to a defective product storage container. In particular, large balls with a diameter of 20 mm or more can be transported by suction, improving inspection efficiency. In other words, this system is suitable for inspecting the outer diameter of ceramic spheres with a diameter of 20 mm or more, especially ceramic spheres with a band-shaped portion.

[0028] Although several embodiments of the present invention have been described above, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. Modifications of these embodiments are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. Furthermore, the above-described embodiments can be implemented in combination with each other. [Explanation of symbols]

[0029] 1...Ceramic sphere inspection device 2... Placement member 3...First placement section 4...Second placement section 5...Ceramic sphere

Claims

1. A ceramic sphere inspection device for inspecting the outer diameter of a ceramic sphere, the arrangement member for arranging the ceramic spheres has a first arrangement portion and a second arrangement portion; placing ceramic spheres in a first placement portion; A ceramic sphere inspection device characterized by having a mechanism for storing ceramic spheres that have been determined to be non-defective after inspection in a second placement section.

2. 2. The ceramic sphere inspection device according to claim 1, wherein the arrangement member has a plurality of first arrangement portions and second arrangement portions, and the number of first arrangement members is the same as the number of second arrangement members.

3. 3. The ceramic sphere inspection device according to claim 1, wherein the ceramic sphere has a band-shaped portion.

4. A ceramic sphere inspection device according to claim 3, characterized in that when a positioning member having a plurality of first positioning portions and second positioning portions is used, the orientation of the strip-shaped portion is aligned within a range of ±20°.

5. 3. The ceramic sphere inspection device according to claim 1, further comprising a mechanism for moving ceramic spheres determined to be defective from the first arrangement section to a defective product storage container.

6. 4. The ceramic sphere inspection device according to claim 3, further comprising a mechanism for moving ceramic spheres determined to be defective from the first arrangement section to a defective product storage container.

7. 5. The ceramic sphere inspection device according to claim 4, further comprising a mechanism for moving ceramic spheres determined to be defective from the first arrangement section to a defective product storage container.

8. 3. The ceramic sphere inspection device according to claim 1, further comprising a mechanism for moving ceramic spheres determined to be non-defective from the second arrangement section to a non-defective product storage container.

9. 4. The ceramic sphere inspection device according to claim 3, further comprising a mechanism for moving ceramic spheres determined to be non-defective from the second arrangement section to a non-defective product storage container.

10. 5. The ceramic sphere inspection device according to claim 4, further comprising a mechanism for moving ceramic spheres determined to be non-defective from the second arrangement section to a non-defective product storage container.

11. 8. The ceramic sphere inspection device according to claim 7, further comprising a mechanism for moving ceramic spheres determined to be non-defective from the second arrangement section to a non-defective product storage container.

12. 3. The ceramic sphere inspection device according to claim 1, wherein the ceramic sphere has an outer diameter of 9 mm or more.

13. 12. The ceramic sphere inspection device according to claim 11, wherein the ceramic sphere has an outer diameter of 9 mm or more.

14. A ceramic sphere inspection method, comprising using the ceramic sphere inspection device according to claim 1 or 2.

15. A ceramic sphere inspection method, comprising using the ceramic sphere inspection device according to claim 13.

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