JP2010127618A - Automatic sphere inspection method and device for the same with ultrasonic flaw detection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and positively detect internal flaws on the surface of a sphere to be inspected and within a depth of 17% of the diameter of the sphere at the same time, and to improve reliability of a product and ease of operation. <P>SOLUTION: The surface of an inspection target sphere 31 and the inside of the sphere within a depth of 17% of the diameter of the sphere are simultaneously inspected at high speed by simultaneously performing the steps of: transmitting ultrasonic waves to the inspection target sphere 31 from an ultrasonic probe 37 for a surface wave method with its center line disposed at a position offset by 20-23% of the diameter of the sphere from the center line of the inspection target sphere by rotating the inspection target sphere 31 in a meridian manner in a liquid with a rotation device, and determining the presence of surface defects and internal defects within 0.4 mm from the sphere surface by waveform signals of returning ultrasonic waves reflected from the sphere surface and the inside near the surface; and transmitting ultrasonic waves to the inspection target sphere 31 from an ultrasonic probe 36 for an inclined wave method disposed at a position offset by 13-15% of the diameter of the sphere from the center line of the inspection target sphere 31, and determining the presence of internal defects within a depth of 17% of the diameter of the sphere from waveform signals of returning ultrasonic waves reflected from the inside of the sphere. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a ball defect in a ball, a ball guide, a linear guide, a constant velocity joint, a ball valve, an optical lens and the like, a ball surface defect that occurs during processing of a ceramic ball, a glass ball, etc., and a material defect that occurs in the ball. (Ultrasonic flaw detection sphere automatic inspection method that detects the presence or absence of defects using ultrasonic waves, such as oxide inclusions for steel, metal inclusions for ceramic balls, and segregation of pores and sintering aids) It relates to an apparatus for carrying out the method.

  Conventionally, in a steel ball appearance inspection apparatus, as shown in FIG. 11, light from a filament of a light source 102 is applied to an inspection target ball 101, and reflected light from the ball is received by a light receiving element 103 to electrically convert a change in received light amount. An optical inspection method is known in which a determination unit 104 determines the presence / absence of a defect based on a change amount of an electric signal after being converted into a change in voltage or current. (For example, refer to Patent Document 1). For internal defect inspection, eddy current inspection and inspection methods using X-rays are also known.

However, in the case of the optical inspection method as described above, in steel balls with a mirror-finished surface used for general bearings, defects occurred during the production of materials existing on the surface and occurred during processing into balls. Although defects can be detected, defects such as oxide inclusions generated during material production do not appear on the surface of the sphere and often exist inside the sphere. In that case, in principle, it is impossible to inspect the inside of the sphere by the optical inspection method. There is a concern that defects such as oxide inclusions generated during the production of the material existing inside the sphere have a great influence on the bearing life when the sphere is used in a bearing or the like. Therefore, eddy current flaw detection and inspection methods using X-rays are usually considered, but in the case of eddy current flaw detection, not only the surface but also defects near the surface can be detected, but the defect is exposed to the surface as a detection condition. However, it is necessary to be open, and it is difficult to detect minute defects that are not exposed on the surface and are completely present inside. Also, in the inspection method using X-rays, generally, when manufacturing a sphere, it is processed in units of lots, the number of lots is from tens of thousands to hundreds of thousands, inspection tact can not be ignored, manual If the inspection is performed, there is a problem that a great labor cost and a processing time are required. On the other hand, a method and an apparatus using ultrasonic waves have been proposed as being capable of rapidly detecting minute defects existing on the rolling surface of the rolling element for bearing and in the vicinity of the surface. (For example, see Patent Document 2)
In this method or apparatus, a rolling element for bearing and an ultrasonic probe are disposed in an ultrasonic transmission medium, and the ultrasonic wave is transmitted from the probe while being rotatably held by a rolling means such as a pump. In this method, defects are detected by reflected ultrasonic echoes, and it is disclosed that it is possible to detect the surface of a rolling element and minute defects existing in the vicinity of the surface within 2 mm from the surface.

Further, as a general ultrasonic detection device, although not a sphere, an ultrasonic wave is transmitted from an ultrasonic wave transmission unit in a state where an inspection object is submerged in a liquid, and an ultrasonic wave transmitted from the transmission unit It is also known to perform inspection by receiving reflected waves. (For example, see Patent Document 3)
JP 2002-277226 A Japanese Patent Publication No. 5-84865 JP 2007-47056 A

  However, even in the inspection of the sphere using the ultrasonic wave, even if it is possible to detect a defect on the surface of the sphere or the surface within 2 mm from the surface of the sphere, there is almost no mention of the inspection inside the sphere. Therefore, depending on the diameter of the sphere, it is not sufficient to detect defects such as inclusions produced during the manufacture of the material existing inside the sphere, and when used in a bearing or the like, a great influence on the bearing life is inevitable. Further, in the manufacturing process of the ceramic sphere, when there are holes or metal foreign objects deep inside, the influence on the product life is inevitable. In particular, it is difficult to manage and control the liquid by rotating the inspection target sphere with an injection means such as a pump, and there is no guarantee that the inspection target sphere is reliably rotating in a meridian shape.

  In view of the actual situation as described above, the present invention copes with this by performing a flaw detection inside a sphere surface of a sphere to be inspected at a depth of 17% as well as a ball surface defect affecting a bearing or the like for optical inspection. Compared to the surface of the sphere and internal defects 17% deeper than the diameter of the sphere to be inspected, it is easy and reliable to detect and improve the reliability of the product. The purpose is to improve the workability by facilitating the coupling of devices and the like, and to inspect and process a large number of balls automatically at high speed.

  That is, the feature of the present invention that meets the above-described purpose is that the inspection object sphere is rotated in a meridian by a rotating device in a liquid, and 20 to 23% of the diameter of the inspection object sphere from the center line of the inspection object sphere. Ultrasound is transmitted from the ultrasonic probe for surface wave method with the center line located at the offset position to the sphere to be inspected, propagated on the sphere surface of the sphere to be inspected and the inside of the surface vicinity, and reflected by the reflection source. The returned ultrasonic wave is received, the returned ultrasonic wave is electrically converted, a waveform signal is obtained, and the presence or absence of surface defects and internal defects within 0.4 mm from the surface of the sphere to be inspected is determined based on the level of the signal At the same time, an ultrasonic wave is transmitted to the inspection target sphere from the ultrasonic probe for the oblique wave method arranged at a position offset from the center line of the inspection target sphere by 13 to 15% of the diameter of the inspection target sphere. , Propagates inside the sphere to be inspected and is reflected back by the reflection source The ultrasonic wave is received, the returned ultrasonic wave is electrically converted, a waveform signal is obtained, and the presence or absence of a defect up to a depth of 17% of the sphere diameter of the inspection target sphere is determined based on the level of the signal. Thus, the ultrasonic inspection system automatic inspection method in which the surface of the sphere and the maximum shear stress position of the sphere are simultaneously inspected at a high speed up to 17%, which is 10 times the depth of 1.7% of the sphere diameter.

  According to a second aspect of the present invention, the inspection target sphere is washed prior to the inspection to improve the cleanliness. A third aspect of the present invention is a process for a sphere that has been subjected to the above inspection, and after the inspection has been completed, the discharged sphere is automatically distributed into a non-defective product and a defective product, and a new inspection target sphere is thrown into the inspection section. And

  Claim 4 is an inspection apparatus for carrying out the above-described inspection method, comprising a drive roller, a support roller and a control roller with an eccentric helical gear that are immersed in the liquid, and a twist on the ball to be inspected by rotation of the control roller to give a meridian And a device having a center line disposed at a position offset by 20 to 23% of the sphere diameter of the inspection object sphere from the center line of the inspection object sphere supported in the liquid by the apparatus From the ultrasonic probe for the wave method and the ultrasonic probe for the oblique wave method in which the center line is arranged at a position offset by 13 to 15% of the sphere diameter of the inspection object sphere from the center line of the inspection object sphere Each ultrasonic wave transmitted at the same time is received simultaneously with each ultrasonic wave reflected and returned from the surface of the sphere to be inspected, in the vicinity of the surface, and inside, and electrically converted to process each signal simultaneously. A signal processing unit, characterized in that said formed of liquid in apparatus for removing the immersed liquid the ultrasonic probe.

  By using the ultrasonic flaw detection type sphere automatic inspection method of the present invention, the surface of the sphere and the maximum shear stress depth of the sphere inside the sphere up to 17% depth, which is 10 times the depth of the sphere diameter of 1.7%. It is possible to stably detect harmful micro-defects, and in particular, the maximum shearing of the sphere as well as the entire surface of the sphere, coupled with the fact that the entire surface of the sphere is scanned in a meridian form sequentially with the rotating device. Automatic inspection up to 17% depth of the sphere diameter, which is 10 times the 1.7% depth of the sphere diameter, which is the stress position, is more reliably performed, improving the life and reliability of the product compared to the conventional method. At the same time, labor costs and processing time can be greatly reduced compared to manual inspection, and workability can be improved.

  In addition, internal inspections of defective spheres can be further conducted by X-ray inspection, CT microscanning, etc., and the contents of the defects can be grasped to make a request for improvement to the supplier, leading to improvement of the quality of the basic sphere.

  Hereinafter, specific embodiments of the present invention will be described. FIG. 1 is an overall schematic diagram showing one mode of an inspection apparatus for carrying out the present invention, and FIG. 2 is a schematic diagram showing a main part of the inspection apparatus constituting the main part of the present invention.

  As shown in FIG. 1, an inspection apparatus for carrying out the inspection of the present invention includes a supply apparatus 1 for supplying an inspection object sphere, a cleaning apparatus 2 including an automatic brush cleaning apparatus for cleaning the supplied inspection object sphere before the inspection, and immersion in a liquid. The inspection unit 3 having the rotation mechanism is sequentially arranged, the submerged purification device 4 for purifying the liquid of the inspection unit 3, the receiving box 5 for receiving the ball after the inspection, the supply device 1, the washing Although the whole is configured by combining the apparatus 2 with a pump unit 6 for feeding the cleaning liquid, this arrangement is related to the application of the present applicant, except for the inspection method in the inspection unit 3 described later. Since it is described in detail in Japanese Patent Application Laid-Open No. 2002-277226, detailed description will be omitted, and only the configuration of the inspection unit that is a feature of the present invention will be described below with reference to FIG.

  FIG. 2 shows an example of the configuration of the inspection unit constituting the main part of the present invention. In the figure, reference numeral 31 indicates a sphere to be inspected, and the sphere 31 includes a drive roller 32, a support roller 33 and a control which are immersed in the liquid. The roller 34 is held at a predetermined position. An eccentric helical gear 35 is attached to the control roller 34. By rotating the drive roller 32, the inspection target ball 31 rotates, and thereby the eccentricity attached by the control roller 32, the support roller 33, and the control roller 34. The inspection target sphere 31 is rotated by the helical gear 35, and the control roller 34 is also rotated. At this time, the inspection target sphere 31 is twisted by the eccentric helical gear 35 attached to the control roller 34. 31 has a mechanism that rotates in a meridian manner.

  In the figure, reference numerals 36 and 37 denote ultrasonic probes for the surface wave method and the oblique wave method, which are important elements in the ultrasonic method inspection of the present invention. The center line is arranged at a position in the liquid that is offset by 20 to 23% of the sphere diameter of the inspection object sphere 31 from the center line of the inspection object sphere 31 rotating in a meridian by the series of rotation devices, and the meridian Ultrasonic waves are transmitted to the sphere surface of the inspection target sphere 31 that is rotating at the same time. The ultrasonic wave transmitted from the ultrasonic probe for surface wave method 36 goes straight to the inspection object sphere 31 and is regularly reflected on the surface of the inspection object sphere 31 to return to the ultrasonic probe for surface wave method 36. Sound waves, ultrasonic waves that propagate along the surface of the sphere 31 along the surface of the inspection object sphere 31, and ultrasonic waves that propagate near the sphere surface on the surface of the inspection object sphere 31.

  If there is a defect on the sphere surface at the time of manufacturing the sphere, or if there is a defect on the surface of the sphere at the time of manufacturing the material, the ultrasonic wave or the sphere surface that propagates along the surface of the sphere 31 to be inspected. The ultrasonic wave propagates in the vicinity, the ultrasonic wave is reflected at the defective portion, and returns to the ultrasonic probe following the same path. Here, if there is a material flaw attached at the time of material production inside the inspection object sphere 31, since the ultrasonic wave transmitted from the ultrasonic probe 36 for surface wave method does not propagate to the inside, flaw detection becomes impossible. In this case, the flaw detection can be performed with the oblique wave method ultrasonic probe 37 which is another probe described later.

  On the other hand, the oblique wave method ultrasonic probe 37 is a liquid offset by 13 to 15% of the diameter of the inspection object sphere 31 from the center line of the inspection object sphere 31 rotating in a meridian shape by the series of rotating devices. An ultrasonic wave is transmitted to the sphere surface of the sphere 31 to be inspected, which has a center line arranged at a predetermined position and is rotating in a meridian shape.

  The ultrasonic wave transmitted from the oblique wave method ultrasonic probe 37 goes straight to the inspection object sphere 31 and is regularly reflected on the surface of the inspection object sphere 31 to the oblique wave method ultrasonic probe 37. The returning ultrasonic waves are classified into ultrasonic waves that enter and propagate inside the sphere on the surface of the inspection target sphere 31. If there is a defect in the sphere at the time of manufacturing the material, the ultrasonic wave is reflected at the defective portion by the ultrasonic wave propagating inside the sphere 31 to be inspected, and returns to the ultrasonic probe through the same path. It will be. Here, for example, if there is a defect in the vicinity of the surface of the inspection target sphere 31 when the material is manufactured, the inspection may be impossible due to the influence of echoes reflected on the surface of the inspection target sphere 31. In that case, flaw detection becomes possible with the above-described surface acoustic wave method ultrasonic probe 36. Then, the returned ultrasonic waves are electrically converted by the converter 40 to obtain a signal as a waveform. By determining the level of the signal, the presence or absence of surface defects and internal defects can be determined.

  In addition, after the inspection is completed, the support roller 33 holding the ball is operated, and the ball is discharged from the inspection unit. A discrimination gate 38 for distributing the non-defective product and the defective product is installed in the discharged portion. Depending on the inspection result, the discrimination gate 38 is activated and automatically sorted into a non-defective product and a defective product. On the other hand, at the same time as the balls are discharged, only one next ball 41 waiting for the straightening finger 39 to move up and down is put into the inspection section, and the inspection can be continuously performed by repeating this operation.

  Here, as the ultrasonic probe 36 for the surface wave method to be used, a steel ball having a sphere diameter of about 10 to 20 mm, for example, about 17.5 mm is inspected depending on the sphere diameter and material of the sphere to be inspected. Therefore, a frequency of about 10 to 30 MHz and an element diameter of about 3 to 6 mm are preferable in terms of inspection capability. When inspecting ceramic spheres, a frequency of 20 to 50 MHz and an element diameter of about 3 to 6 mm are preferable in terms of inspection capability. In addition, as the oblique wave method ultrasonic probe 37, depending on the sphere diameter and material of the sphere to be inspected, in order to inspect a steel sphere having a sphere diameter of about 10 to 20 mm, for example, about 14.5 mm, A frequency of about 10 to 30 MHz and an element diameter of about 3 to 6 mm are preferable in terms of inspection capability. Moreover, the jig to which the ultrasonic probe is attached has a structure that can be easily adjusted in the vertical and horizontal directions, and can transmit ultrasonic waves to any location of the sphere.

  The liquid in which the rotating device and the ultrasonic probe are immersed is purified by the liquid purification device, and fine objects such as dust and dirt and bubbles are removed in the liquid. Yield deterioration due to pseudo defect signals due to minute objects and bubbles is prevented, and inspection accuracy is improved. Further, as the liquid used here, not only oil but also water can be used, but oil is used in the present invention in consideration of rusting of the machine. Next, examples of the inspection will be described.

  Using the above device, a sphere with a sphere diameter of 17.5 mm was rotated in a meridian by rotation of a drive roller, a support roller, and a control roller, and an ultrasonic wave was transmitted to the sphere surface by an ultrasonic probe for the oblique wave method. . When the transmitted ultrasonic waves are propagated back to the inside of the sphere, the ultrasonic waves are received and confirmed by the waveform signal by the converter, and the waveform as shown in FIG. However, when a sphere determined to be defective was confirmed by ultrasonic flaw detection for the oblique wave method, a signal that seems to be a defect as shown in FIG. 3B was confirmed. Therefore, when the sphere on which the signal that seems to be a defect was confirmed was confirmed with a microscope, the defect was not confirmed on the sphere surface. Therefore, as a result of checking with a microscope each time cutting the surface of the sphere by several μm, a defect of 300 μm oxide inclusions as shown in FIG. 7 was confirmed in the vicinity of a depth of about 500 μm.

  In addition, ultrasonic waves are transmitted to the sphere to be inspected by the ultrasonic probe for the surface wave method, and ultrasonic waves that are propagated through the sphere surface of the sphere to be inspected and the vicinity of the surface and reflected by the reflection source are received. When the returned ultrasonic wave was confirmed by a waveform signal by electrical conversion, a waveform as shown in FIG. 4 (a) was found for a normal part, but a sphere determined to be defective was detected by ultrasonic flaw detection for the surface wave method. As a result, a signal that seems to be a defect as shown in FIG. Therefore, when the sphere on which the signal that seems to be a defect was confirmed was confirmed with a microscope, the defect was not confirmed on the sphere surface. Therefore, as a result of checking with a microscope each time cutting the surface of the sphere by several μm, a defect of 160 μm oxide inclusions as shown in FIG. 8 was confirmed in the vicinity of a depth of about 400 μm.

  In addition, when the ultrasonic wave transmitted to the sphere surface by the ultrasonic probe for the oblique wave method is received and returned to the inside of the sphere, and confirmed by the waveform signal with the transducer, A signal that seems to be a defect as shown in FIG. Therefore, a sphere with a signal that seems to be defective is transmitted to the sphere to be inspected by the ultrasonic probe for surface wave method, propagated on the sphere surface of the sphere to be inspected and inside the vicinity of the surface, and ultrasonic waves are transmitted by the reflection source The ultrasonic waves that were reflected and received were received, and the returned ultrasonic waves were confirmed by a waveform signal by electrical conversion. As a result, a signal as shown in FIG. 5B was confirmed and was not determined to be a defect. Therefore, as a result of confirming with a microscope each time cutting the surface of the sphere by several μm, a 150 μm metallic foreign substance as shown in FIG. 9 was found in the vicinity of a depth of about 2.975 mm, which is 17% of the diameter of the sphere to be inspected. Defects were confirmed.

  In addition, ultrasonic waves are transmitted to the sphere to be inspected by the ultrasonic probe for the surface wave method, and ultrasonic waves that are propagated through the sphere surface of the sphere to be inspected and the vicinity of the surface and reflected by the reflection source are received. When the returned ultrasonic wave was confirmed by a waveform signal by electrical conversion, a signal that seems to be a defect as shown in FIG. 6 (a) was confirmed. Therefore, an ultrasonic wave is transmitted to the sphere to be inspected by the ultrasonic probe for the oblique wave method, and the ultrasonic wave is propagated through the sphere of the sphere to be inspected and reflected by the reflection source. When the ultrasonic waves returned were received and the returned ultrasonic waves were confirmed by a waveform signal by electrical conversion, a signal as shown in FIG. 6B was confirmed and was not determined to be a defect. Therefore, when the surface of the sphere in which a signal that seems to be a defect as shown in FIG. 6 (a) was confirmed was confirmed with a microscope, the surface of the sphere as shown in FIG. Defects were confirmed.

  In addition, for the sphere in which no signal that seems to be defective is seen as shown in FIG. 3 (a), the surface of the sphere to be inspected is examined with a microscope each time while checking the surface of the sphere and cutting the surface of the sphere by several μm. Although it was confirmed to a depth of 17%, no defect was confirmed. Therefore, as described above, the ultrasonic inspection of the present invention can simultaneously perform automatic inspection up to 17% depth, which is 10 times the depth of the sphere diameter which is the maximum shear stress position of the sphere surface and the sphere. confirmed.

1 is an overall schematic diagram showing one aspect of an inspection apparatus for carrying out the present invention. It is a schematic diagram which shows the test | inspection part which makes the principal part in this invention test | inspection apparatus. Waveform signal when the ultrasonic wave transmitted to the surface of the sphere by the ultrasonic probe for the oblique wave method and propagated back inside the sphere is received. (B) is normal, (b) is The case where there is a defect is shown. This is a waveform signal when the ultrasonic wave transmitted to the sphere by the ultrasonic probe for the surface wave method and propagated back on the surface of the sphere and the inside of the surface is received. ) Indicates a case where there is a defect. Waveform signal when ultrasonic waves transmitted to the surface of the sphere by the ultrasonic probe for oblique wave method and propagated back inside the sphere are received. (B) If there is a defect, (b) (B) shows a case where there is no defect in the waveform signal transmitted by the surface wave method ultrasonic probe and receiving the ultrasonic wave propagating back on the surface of the sphere and in the vicinity of the surface. Ultrasonic wave is transmitted to the sphere by the ultrasonic probe for the surface wave method, and is a waveform signal that propagates back on the surface of the sphere and the vicinity of the surface, and (b) indicates that there is a defect. ) Is transmitted by the oblique wave method ultrasonic probe, propagates through the inside of the sphere and returns to the waveform signal and is not determined as a defect. It is a microscope picture of the defect part of the said FIG. It is a microscope picture of the defect part of the said FIG. It is a microscope picture of the defective part of the said FIG. It is a microscope picture of the defect part of the said FIG. It is a schematic diagram of the apparatus which enforces the conventional optical inspection method.

Explanation of symbols

31: Sphere to be inspected 32: Drive roller 33: Support roller 34: Control roller 35: Eccentric helical gear 36: Ultrasonic probe for oblique wave method 37: Ultrasonic probe for surface wave method 38: Discrimination gate 39: Commutation finger 40: Converter 41: Standby ball

Claims (4)

  The inspection object sphere is rotated in a meridian by a rotating device in the liquid, and the center line is arranged at a position offset (displaced) by 20 to 23% of the diameter of the inspection object sphere from the center line of the inspection object sphere. The ultrasonic wave is transmitted from the ultrasonic probe for the surface wave method to the sphere to be inspected, and the ultrasonic wave that is propagated through the sphere surface of the sphere to be inspected and the inside of the vicinity of the surface and reflected by the reflection source is returned, The returned ultrasonic wave is electrically converted, a waveform signal is obtained, and the level of the signal determines the presence or absence of surface defects and internal defects within 0.4 mm from the surface of the inspection target sphere, and at the same time the center of the inspection target sphere An ultrasonic wave is transmitted from the ultrasonic probe for oblique wave method arranged at a position offset from the line by 13 to 15% of the sphere diameter of the sphere to be inspected to the sphere to be inspected, and propagates inside the sphere to be inspected. Received and returned ultrasound reflected by the reflection source By performing electrical conversion, obtaining a waveform signal, and simultaneously determining whether or not there is a defect having a depth of 17% of the sphere diameter of the sphere to be inspected based on the level of the signal, the surface of the sphere and the maximum shear stress of the sphere An ultrasonic flaw detection type sphere automatic inspection method characterized by simultaneously inspecting at a high speed up to 17% depth, which is 10 times the 1.7% depth of the sphere diameter as a position.   2. The ultrasonic flaw detection type sphere automatic inspection method according to claim 1, wherein the inspection target sphere is cleaned prior to the inspection to improve the cleanliness of the surface state.   3. A ball according to claim 1 or 2, wherein after the inspection is completed, the automatically discharged balls are automatically sorted into non-defective products and defective products, stored in a predetermined storage position, and new inspection target balls are automatically inserted into the inspection section. Ultrasonic flaw detection ball automatic inspection method.   A device comprising a drive roller, a support roller, and an eccentric helical gear that is immersed in the liquid, a device that twists the sphere to be inspected by rotation of the control roller and rotates it in a meridian shape, And an ultrasonic probe for surface wave method in which the center line is arranged at a position offset (displaced) by 20 to 23% of the sphere diameter of the sphere to be inspected supported from the center line of the sphere to be inspected Each ultrasonic wave transmitted simultaneously from the oblique wave method ultrasonic probe in which the center line is arranged at a position offset from the center of the target sphere by 13 to 15% of the diameter of the inspection target sphere is converted into the inspection target sphere. A signal processing unit that simultaneously receives and electrically converts each of the ultrasonic waves reflected and returned near and inside the surface, and purifies the liquid in which the ultrasonic probe is immersed To consist purifier submerged ultrasonic flaw detection method sphere automatic inspection apparatus according to claim that.