Ultrasonic flaw detection device for bearings

Abstract

The present invention provides an ultrasonic flaw detection device that can accurately and easily evaluate the cleanliness of the steel materials constituting a bearing. [Solution] The ultrasonic flaw detection device 200 is a device for evaluating the cleanliness of the steel material constituting the bearing 1A by ultrasonic flaw detection, and comprises a large-diameter bearing chuck 41A connected to the output shaft of the motor 20 for fixing the bearing 1A, and an ultrasonic probe 30 positioned opposite the outer diameter surface 12 of the bearing 1A and moving along the outer diameter surface 12 in a direction parallel to the output shaft. The large-diameter bearing chuck 41A has a mounting member 45 fixed to the output shaft, and a plurality of claw portions 40A supported by the mounting member 45 and arranged in the circumferential direction. The claw portions 40A support the bearing 1A from the inner diameter side, and the radial position of the claw portions 40A is supported by the mounting member 45 so as to be movable in accordance with the inner diameter of the bearing 1A.

Description

Technical Field

[0001] The present invention relates to an ultrasonic flaw detector for evaluating the cleanliness of steel materials constituting bearings.

Background Art

[0002] Conventionally, it has been known that the rolling fatigue life of a bearing has a strong correlation with the amount of various inclusions in the steel constituting the bearing. Since a bearing is manufactured using a steel material, it is common to judge the cleanliness of the steel material by measuring the amount of inclusions in this steel material. And by feeding back the result to the steel manufacturing process, steel materials of a certain quality or higher-quality steel materials are manufactured.

[0003] As methods for measuring such inclusions in steel materials, the JIS method (JIS-G0555), the ASTM (American Society for Testing and Materials): E45 method, the extreme value statistics method, etc. are common. Also, as a method with higher measurement accuracy in a shorter time, the applicant has proposed, in Patent Document 1, an evaluation method for measuring the size and number of inclusions in a steel material (round bar) having a predetermined diameter by ultrasonic flaw detection and evaluating the cleanliness of the steel material based on the measurement result.

[0004] [[ID=第十九]] FIG. 8 is a schematic diagram briefly showing a conventional method for evaluating the cleanliness of a steel material (round bar) by ultrasonic flaw detection. As shown in FIG. 8, both ends of a long round bar 100 are supported and fixed by a pair of chuck 110 for bar steel, and while rotating the round bar 100 around its axis C in the R direction by a motor 120, an ultrasonic probe 130 is translated parallel to the outer peripheral surface of the round bar 100 along the longitudinal direction (left-right direction in the figure) of the round bar 100 to detect the size and position of inclusions in the round bar 100. The ultrasonic probe 130 is configured to be supported and moved by, for example, a probe holder 135. <000001۸> According to the evaluation method described above, the inclusions are measured by rotating the round bar 100 while moving the ultrasonic probe 130 parallel to its longitudinal direction. This allows for a large evaluation volume to be set, enabling accurate measurement of the dimensions and number of inclusions. Therefore, the cleanliness of the steel material used for the outer ring, inner ring, and other components of the bearing can be evaluated. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 7092101 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, since bearings are manufactured using steel as the starting material and undergoing various processes, the cleanliness of the starting steel material does not necessarily directly correspond to the cleanliness of the steel material that makes up the final bearing. Therefore, there is a need for technology to accurately and easily measure the cleanliness of the steel material that makes up the bearing.

[0008] This invention has been made in view of the above circumstances, and aims to provide an ultrasonic flaw detection device that can accurately and easily evaluate the cleanliness of the steel material constituting a bearing. [Means for solving the problem]

[0009] The ultrasonic flaw detection device for bearings according to the present invention has the configuration shown in [1] below.

[0010] [1] An apparatus for evaluating the cleanliness of steel materials constituting a bearing by ultrasonic testing, A bearing chuck connected to the output shaft of the motor and for fixing the bearing, The system comprises an ultrasonic probe positioned opposite the outer diameter surface of the bearing and moving along the outer diameter surface in a direction parallel to the output shaft, The bearing chuck comprises a mounting member fixed to the output shaft and a plurality of claws supported by the mounting member and arranged in the circumferential direction. The aforementioned claw portion supports the bearing from the inner diameter side, An ultrasonic flaw detection device for a bearing, characterized in that the radial position of the claw portion is supported by the mounting member so as to be movable in accordance with the inner diameter of the bearing.

[0011] Furthermore, a preferred embodiment of the ultrasonic flaw detection device for bearings according to the present invention is configured as shown in [2] to

[10] below.

[0012] [2] Furthermore, the device includes a probe holder that holds the ultrasonic probe, The ultrasonic flaw detection apparatus for a bearing according to [1], characterized in that the mounting position of the bearing to the bearing chuck is restricted so that the ultrasonic probe and the probe holder do not come into contact with the bearing chuck. [3] The bearing ultrasonic flaw detection apparatus for a bearing according to [1] or [2], characterized in that the bearing is supported in a cantilevered manner by the bearing chuck. [4] The bearing chuck is provided with an extension portion that is mounted on the jaw portion and extends in a direction away from the mounting member, and the bearing is supported on the jaw portion via the extension portion, as described in any one of [1] to [3]. [5] By making the outer diameter of the claw portion smaller than the outer diameter of the mounting member, a stepped portion is formed between the claw portion and the mounting member. An ultrasonic flaw detection device for a bearing according to any one of [1] to [4], characterized in that a bearing is placed in the stepped portion. [6] The bearing ultrasonic flaw detection apparatus according to any one of [1] to [5], characterized in that at least an outer ring is used as the bearing, and the inner diameter surface of the outer ring of the bearing is fixed to the bearing chuck. [7] The ultrasonic flaw detection device for a bearing according to any one of [1] to [5], characterized in that at least an inner ring is used as the bearing, and the inner diameter surface of the inner ring of the bearing is fixed to the bearing chuck. [8] The bearing ultrasonic flaw detection device according to any one of [1] to [5], wherein at least an outer ring, an inner ring, and rolling elements are used as the bearing, the inner diameter surface of the pre-assembled inner ring of the bearing is fixed to the bearing chuck, and the device has a fixing member that suppresses relative rotation between the outer ring and the inner ring. [9] The ultrasonic flaw detection apparatus for a bearing according to [8], characterized in that the fixing member is a magnet that connects and fixes the outer ring and the inner ring.

[10] The ultrasonic flaw detection apparatus for a bearing according to [8], characterized in that the fixing member comprises a retaining member disposed on the axial end face of the outer ring and the inner ring opposite to the mounting member side, and a wing bolt that fastens the mounting member and the retaining member in a direction that brings them closer together to fix the outer ring and the inner ring. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide an ultrasonic flaw detection device that can accurately and easily evaluate the cleanliness of the steel material constituting a bearing. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a diagram showing an ultrasonic flaw detection apparatus according to a first embodiment of the present invention, and is a schematic diagram showing how a large-diameter outer ring 10A of a large-diameter bearing 1A is fixed. [Figure 2] Figure 2 is a schematic diagram showing an ultrasonic flaw detection apparatus according to the first embodiment of the present invention, illustrating how the medium-diameter outer ring 10B of the medium-diameter bearing 1B is fixed. [Figure 3] Figure 3 is a schematic diagram showing an ultrasonic flaw detection apparatus according to the first embodiment of the present invention, illustrating how a small-diameter outer ring 10C of a small-diameter bearing 1C is fixed. [Figure 4] Figure 4 is a schematic diagram showing a modified example of the ultrasonic flaw detection apparatus according to the first embodiment. [Figure 5] Figure 5 is a schematic diagram showing another modified example of the ultrasonic flaw detection apparatus according to the first embodiment. [Figure 6] FIG. 6 is a schematic diagram showing an ultrasonic flaw detector according to a second embodiment of the present invention. [Figure 7] FIG. 7 is a schematic diagram showing a modified example of the ultrasonic flaw detector according to the second embodiment. [Figure 8] FIG. 8 is a schematic diagram simply showing a conventional method for evaluating the cleanliness of a steel material (round bar) by ultrasonic flaw detection. [Figure 9] FIG. 9 is a schematic diagram showing a reference example of an ultrasonic flaw detector. **Embodiments for Carrying Out the Invention**

[0015] As a result of intensive studies to solve the above problems, the inventors of the present invention have found that it is possible to measure the cleanliness of the steel material itself constituting the bearing by using an ultrasonic flaw detection method for round bars that enables more accurate measurement of inclusions in a short time. Therefore, various studies have been conducted to obtain an ultrasonic flaw detector. As a result, it has been found that securely fixing the bearing and ensuring the measurement range in the axial direction of the bearing are important for realizing accurate measurement of inclusions. The present invention has been made based on this finding.

[0016] Hereinafter, the present invention will be described in detail with reference to the drawings. In the description of the embodiments shown below, a "ball bearing" will be exemplified for explanation, but the present invention is not limited thereto, and can be arbitrarily modified and implemented without departing from the gist of the present invention.

[0017] (First Embodiment) FIG. 1 is a diagram showing an ultrasonic flaw detector according to a first embodiment of the present invention, and is a schematic diagram showing a state in which a large-diameter outer ring 10A of a large-diameter bearing 1A is fixed. Further, FIG. 2 is a diagram showing an ultrasonic flaw detector according to a first embodiment of the present invention, and is a schematic diagram showing a state in which a medium-diameter outer ring 10B of a medium-diameter bearing 1B is fixed. Furthermore, FIG. 3 is a diagram showing an ultrasonic flaw detector according to a first embodiment of the present invention, and is a schematic diagram showing a state in which a small-diameter outer ring 10C of a small-diameter bearing 1C is fixed.

[0018] As shown in Figure 1, the ultrasonic flaw detection device 200 includes a motor 20, a large-diameter bearing chuck 41A connected to the output shaft (not shown) of the motor 20 for fixing the bearing 1A, and an ultrasonic probe 30 positioned opposite the outer diameter surface of the bearing 1A and moving parallel to this outer diameter surface. The large-diameter bearing chuck 41A has a disc-shaped mounting member 45 and three claws 40A arranged circumferentially on one surface of the mounting member 45, and the claws 40A support the outer ring 10A from the inner diameter side. For example, if the inner circumferential surface 11 of the outer ring 10A of the bearing 1A has a diameter DA, the outer diameter surface (circumscribed circle) of the claws 40A can also be adjusted to a diameter DA, and the bearing 1A is fixed by fitting a part or all of the inner circumferential surface 11 of the outer ring 10A with the claws 40A. In this specification, the outer diameter surface of a claw portion refers to the radially outer diameter surface of a plurality of claw portions, and the diameter of the outer diameter surface of a claw portion, or the diameter of a claw portion, refers to the diameter of a circle assumed to be circumscribed by the claw portion.

[0019] More specifically, the claw portion 40A is supported on the mounting member 45 via a screw mechanism or cam mechanism, etc., so as to be movable in the radial direction of the mounting member 45, that is, in the direction toward or toward the center of the disc-shaped mounting member 45. Therefore, by adjusting the radial position of the claw portion 40A to match the inner diameter of the outer ring 10A and bringing the outer diameter surface of the claw portion 40A into contact with the outer ring 10A, the claw portion 40A is fixed in a position that reliably supports the outer ring 10A.

[0020] Furthermore, the ultrasonic probe 30 is held by the probe holder 35 so as to be movable in a direction parallel to the output shaft of the motor 20 (direction X in the figure).

[0021] A method for evaluating the cleanliness of the steel material constituting the outer ring 10A of a bearing 1A using the ultrasonic flaw detection apparatus 200 according to the first embodiment will be described below. First, the motor 20 rotates the outer ring 10A in the R direction together with the large-diameter bearing chuck 41A, while moving the ultrasonic probe 30 together with the probe holder 35 in the X direction in the figure (i.e., the direction away from the large-diameter bearing chuck 41A). At this time, the ultrasonic probe 30 emits ultrasonic waves U toward the outer circumferential surface of the outer ring 10A and performs ultrasonic flaw detection by detecting the echo reflected from the outer ring 10A.

[0022] After ultrasonic testing is completed, the cleanliness is evaluated by calculating a cleanliness index from the testing results. Cleanliness has a strong correlation with bearing life, and cleanliness parameters that correlate with life include inclusion size and number of inclusions. Therefore, the cleanliness index can be calculated using the size and number of inclusions. The method for calculating the cleanliness index is not particularly limited and can be set appropriately according to the application and type of steel. For example, the cleanliness index may be set so that a higher value indicates worse cleanliness, and the index may be set so that it increases as the number of large inclusions increases. Alternatively, for example, the square root of the area of ​​the inclusions used in extreme value statistics may be calculated from the dimensions of the detected inclusions, and the value determined from the size and number of inclusions for which this square root of area is greater than or equal to a predetermined value may be used as the cleanliness index.

[0023] Ultrasonic testing, which uses ultrasound to perform non-destructive inspections, is a method called NSK-Micro-UT. TM Since the (Ultrasonic Testing) method (trademark application pending by NSK Ltd.) is publicly known, a detailed explanation will be omitted.

[0024] The travel distance of the ultrasonic probe 30 in the X direction is a predetermined width corresponding to the outer diameter surface 12 of the outer ring 10A, and is preferably made as long as possible. The movement of the ultrasonic probe 30 can be carried out in a liquid tank containing an ultrasonic transmission medium such as water, kerosene, or industrial cleaning agent, as described in Patent Document 1, for example. Similarly, control such as signal processing of the ultrasonic probe 30 can be carried out in the same manner. Therefore, the illustration and explanation of the control of the liquid tank and the ultrasonic probe 30 are omitted.

[0025] If we were to attempt to measure inclusions in the steel material constituting the outer ring 10A by holding the outer ring 10A with a chuck from the outer diameter side, in the same manner as the method for holding the round bar described in Patent Document 1, the outer ring 10A has a shorter axial length (width) compared to the round bar. As a result, the area held by the chuck would be obscured by the chuck, making it impossible to secure the desired evaluation volume. Since larger inclusions have fewer occurrences per evaluation volume, if the evaluation volume is small, it may not be possible to detect large inclusions when they are the target of measurement.

[0026] In contrast, according to the method using the ultrasonic flaw detection device 200 of the first embodiment described above, since the outer ring 10A is supported from the inner diameter side by the large-diameter bearing chuck 41A, the size and number of inclusions can be measured over the entire axial width of the outer ring 10A, or over the entire area excluding the chamfered region. Therefore, a sufficient axial measurement range of the bearing 1A can be secured, and accurate measurement of inclusions can be achieved.

[0027] Here, one possible method for holding the outer ring of the bearing from the inner diameter side is the method shown in the following example. The example will be explained with reference to Figure 9.

[0028] (Reference example) Figure 9 is a schematic diagram showing a reference example of an ultrasonic flaw detection apparatus. As shown in Figure 9, one possible method is to support and fix both ends of a long fixed rod 50 with a pair of fixed rod chucks 60, and then fit and fix the inner circumferential surface 11 of the outer ring 10 of the bearing 1 to be measured to the fixed rod 50. The outer ring 10 is fixed, for example, to the center of the fixed rod 50 in the longitudinal direction, so as to be sufficiently far from the fixed rod chucks 60 in the longitudinal direction of the fixed rod 50. Then, the motor 20 rotates the fixed rod 50 in the R direction, and moves the ultrasonic probe 30 together with the probe holder 35 in the X direction in the figure. The distance the ultrasonic probe 30 moves in the X direction is at least the entire width (left and right direction in the figure) of the outer diameter surface 12 of the outer ring 10 of the bearing 1, or the entire area excluding the chamfered area.

[0029] According to the method shown in Figure 9, the size and number of inclusions can be measured over the entire range of movement of the ultrasonic probe 30 in the X direction. However, there are many different types of bearings 1 available on the market, and there is no standard for the inner diameter of the outer ring of a bearing; the inner diameter varies depending on the equipment and location in which it is used. Therefore, it is necessary to prepare a very large number of fixing rods 50 to match the inner diameter of the outer ring to be measured, which increases measurement costs and man-hours. Furthermore, if a fixing rod 50 with an outer diameter slightly smaller than the inner diameter of the outer ring 10 is used, the outer ring 10 will run out when the fixing rod 50 is rotated, making accurate measurement of inclusions difficult. Moreover, if a long fixing rod 50 is used and both ends of the fixing rod 50 are supported, the entire device becomes large.

[0030] When using the ultrasonic flaw detection apparatus 200 according to the first embodiment, the outer ring 10A is directly fixed by a large-diameter bearing chuck 41A, which has a size that allows the outer ring 10A to be securely fixed from the inner diameter side, thus suppressing runout in the outer ring 10A. Furthermore, as described above, the width (left-right direction in the figure) of the outer diameter surface 12 of the outer ring 10A is extremely small, so the amount of eccentricity due to rotation is also small. In addition, the jaw portion 40A of the large-diameter bearing chuck 41A is adjustable in the radial direction of the mounting member 45, and can securely grip outer rings 10A having various inner diameters. Therefore, as shown in Figure 1, even if the outer diameter surface of the jaw portion 40A is in a cantilever state supporting only a part of the inner circumferential surface 11 of the outer ring 10A, runout due to eccentricity can be sufficiently suppressed, and accurate ultrasonic flaw detection becomes possible. Moreover, since the jaw portion 40A of the large-diameter bearing chuck 41A can directly hold the outer ring 10A, the ultrasonic flaw detection apparatus can be made more compact compared to the reference example.

[0031] In the ultrasonic flaw detection apparatus according to an embodiment of the present invention, the bearing chuck is configured such that the radial position of the jaw portion can move to match the inner diameter of the bearing. However, depending on the size of the outer ring of the bearing, it may be difficult to accommodate the bearing by moving only the jaw portion. Therefore, as shown in Figure 2, it is preferable to prepare a medium-diameter bearing chuck 41B that corresponds to a bearing with a smaller diameter than the large-diameter bearing 1A in Figure 1 (medium-diameter bearing 1B), and as shown in Figure 3, a small-diameter bearing chuck 41C that corresponds to a bearing with a smaller diameter than bearing 1B (small-diameter bearing 1C). This allows the diameter DB of the jaw portion 40B of the medium-diameter bearing chuck 41B to match the diameter of the inner circumferential surface 11 of the outer ring 10B of the medium-diameter bearing 1B, or the diameter DC of the jaw portion 40C of the small-diameter bearing chuck 41C to match the diameter of the inner circumferential surface 11 of the outer ring 10C of the small-diameter bearing chuck 41C. As a result, inclusions can be accurately measured for outer rings 10B and 10C of various sizes without generating runout during measurement.

[0032] Furthermore, the ultrasonic flaw detection apparatus shown in Figures 2 and 3 can perform ultrasonic flaw detection over the entire width of the outer diameter surface 12 of the outer rings 10B and 10C. The size and number of inclusions can be measured over the entire axial width of the outer ring 10A, or over the entire area excluding the chamfered region. Therefore, a sufficient axial measurement range of the bearing 1A can be ensured, enabling accurate measurement of inclusions.

[0033] Figure 4 is a schematic diagram showing a modified example of the ultrasonic flaw detection apparatus according to the first embodiment. For example, in Figure 1, the outer ring 10A is used as is immediately after manufacturing, or the outer ring 10A is removed by disassembling the bearing 1A after manufacturing and fixed to the large-diameter bearing chuck 41A. In contrast, the ultrasonic flaw detection apparatus 201 shown in Figure 4 performs measurements using a pre-assembled bearing 1 (outer ring 10, inner ring 15, rolling elements 17), and the inner diameter surface 16 of the inner ring 15 is fitted and fixed to the large-diameter bearing chuck 41A. At that time, the position of the jaw portion 40 is adjusted so that the outer diameter of the jaw portion 40 of the large-diameter bearing chuck 41A matches the inner diameter surface 16 of the inner ring 15.

[0034] Furthermore, in the ultrasonic flaw detection apparatus 201 shown in Figure 4, since the bearing 1 is measured in a pre-assembled state, a fixing member is attached to suppress the relative rotation of the outer ring 10 and the inner ring 15. Specifically, for example, an annular magnet 5 is placed as a fixing member on the axial end face (right side in the figure) of the outer ring 10 and the inner ring 15 opposite to the mounting member 45 side. If the outer ring 10 and the inner ring 15 were not fixed by the fixing member, when ultrasonic flaw detection is performed by the ultrasonic probe 30 while the motor 20 rotates the inner ring 15 in the R direction via the large-diameter bearing chuck 41A, there is a risk that the outer ring 10 will rotate freely relative to the inner ring 15. In that case, the outer ring 10 being subjected to ultrasonic flaw detection may not rotate, and it may not be possible to ultrasonically inspect its outer diameter surface 12 along the circumferential direction. In contrast, the ultrasonic flaw detection device 201 has an annular magnet 5 attached as a fixing member to prevent the outer ring 10 from rotating freely relative to the inner ring 15, so that the bearing 1 can be fixed integrally with the bearing chuck 41 and ultrasonic flaw detection can be performed reliably.

[0035] Furthermore, by making the outer diameter of the claw portion 40 smaller than the outer diameter of the mounting member 45, a stepped portion is formed between the claw portion 40 and the mounting member 45. When the inner ring 15 (bearing 1) is placed on this stepped portion, the movement of the inner ring 15 toward the mounting member 45 (to the left in the figure) is restricted, thereby preventing the inner ring 15 (bearing 1) from sliding laterally in the left-right direction in the figure.

[0036] Furthermore, as a fixing member to prevent the outer ring 10 from rotating freely relative to the inner ring 15, for example, the configuration shown in Figure 5 can be used. Figure 5 is a schematic diagram showing another modified example of the ultrasonic flaw detection apparatus according to the first embodiment. The ultrasonic flaw detection apparatus 202 shown in Figure 5 also performs measurements using a pre-assembled bearing 1 (outer ring 10, inner ring 15, rolling elements 17). As fixing members, a retaining member 6 is used, which is positioned on the axial end face of the outer ring 10 and inner ring 15 opposite to the mounting member 45 side, and a wing bolt 7 is used to press this retaining member toward the mounting member 45 side. Specifically, by tightening the mounting member 45 and the retaining member 6 toward each other with the wing bolt 7, the outer ring 10 and the inner ring 15 are fixed, and by preventing the outer ring 10 from rotating freely relative to the inner ring 15, accurate ultrasonic flaw detection can be performed.

[0037] In the ultrasonic flaw detection apparatus 200 shown in Figure 1, when the ultrasonic probe 30 is held by a probe holder 35, if the distance between the large-diameter bearing chuck 41A and the ultrasonic probe 30 is short, the large-diameter bearing chuck 41A, the ultrasonic probe 30, and the probe holder 35 may come into contact, restricting the movement of the ultrasonic probe 30. Contact between the large-diameter bearing chuck 41A and the ultrasonic probe 30 is likely to occur under various conditions, not only depending on the distance between them, but also when the bearing is small or the probe holder 35 is large. As a result, it becomes difficult to measure the size and number of inclusions over the entire axial width of the bearing 1, or over the entire area excluding the chamfered region, and it becomes necessary to repeat measurements multiple times in order to obtain accurate measurements. Therefore, when using an ultrasonic flaw detection device according to an embodiment of the present invention, it is preferable that the mounting position of the bearing 1A to the large-diameter bearing chuck 41A is restricted so that the ultrasonic probe 30 and the probe holder 35 do not come into contact with the large-diameter bearing chuck 41A.

[0038] An example of restricting the mounting position of bearing 1A to the large-diameter bearing chuck 41A will be explained using Figure 1. For example, it is preferable to adjust the mounting position of bearing 1 so that the ultrasonic probe 30 and the motor-side end 35a of the probe holder 35 do not come into contact with the large-diameter bearing chuck 41A. More specifically, as shown in Figure 1, the outer diameter 45d of the mounting member 45 of the large-diameter bearing chuck 41A can be designed to be small enough that it does not interfere with the height indicated by the dotted line in the figure, which shows the movement trajectory of the probe holder 35, or the outer ring 10A can be held at the tip of the jaw portion 40A of the large-diameter bearing chuck 41A.

[0039] (Second Embodiment) Figure 6 is a schematic diagram showing an ultrasonic flaw detection apparatus according to a second embodiment of the present invention. In the ultrasonic flaw detection apparatus 203 according to the second embodiment, the bearing chuck 41 is provided with an extension portion 47 for restricting the mounting position of the bearing 1 to the bearing chuck 41, and the outer ring 10 of the bearing 1 is fitted into this extension portion 47 to fix the outer ring 10. More specifically, the extension portion 47 is attached to the jaw portion 40 of the bearing chuck 41 and has a shape that extends in a direction away from the mounting member 45 of the bearing chuck 41 (direction X in the figure), in other words, in the direction in which the ultrasonic probe 30 moves.

[0040] In the first embodiment described above, the outer ring 10 or inner ring 15 of the bearing 1 was directly fitted and fixed to the bearing chuck 41. In contrast, in the ultrasonic flaw detection apparatus 203 according to the second embodiment, the extension portion 47 is mounted on a radially movable claw portion 40, and the outer ring 10 is fixed from the inner diameter side by the claw portion 40 via the extension portion 47. Furthermore, since the extension portion 47 is radially movable, similar to the claw portion 40, the outer ring 10 can be securely fixed by the extension portion 47, enabling accurate ultrasonic flaw detection. Moreover, according to the ultrasonic flaw detection apparatus 203 according to the second embodiment, the ultrasonic probe 30 and the probe holder 35 can be sufficiently spaced apart so that they do not come into contact with the bearing chuck 41. Therefore, ultrasonic flaw detection can be accurately performed over a wide area, including the entire axial width of the outer diameter surface 12 of the outer ring 10, or the entire area excluding the chamfered region.

[0041] Furthermore, in the ultrasonic flaw detection device 203, the extension portion 47 has a main body portion 47A that is attached to the claw portion and a tip portion 47B that is located in the X direction relative to the main body portion 47A. The tip portion 47B is smaller in diameter than the main body portion 47A and can be adjusted to coincide with the inner circumferential surface 11 of the outer ring 10. Therefore, by fitting the outer ring 10 onto the tip portion 47B and fixing the outer ring 10 to the stepped portion formed by the main body portion 47A and the tip portion 47B, lateral slippage of the outer ring 10 in the left-right direction in the figure can be prevented.

[0042] Figure 7 is a schematic diagram showing a modified example of the ultrasonic flaw detection apparatus according to the second embodiment. The modified example shown in Figure 7 uses the same ultrasonic flaw detection apparatus 203 as the second embodiment, and supports the inner ring 15 of the pre-assembled bearing 1 from the inner diameter side via the tip portion 47B of the extension portion 47, similar to the modified example of the ultrasonic flaw detection apparatus according to the first embodiment (see Figure 4). In addition, in the modified example shown in Figure 7, a fixing member is used to prevent the outer ring 10 from rotating freely relative to the inner ring 15, and as the fixing member, for example, an annular magnet 5 can be used.

[0043] In the ultrasonic flaw detection apparatus 203 shown in Figure 7, the bearing 1 can be securely fixed, and the ultrasonic probe 30 and probe holder 35 can be sufficiently spaced apart so that they do not come into contact with the bearing chuck 41. Therefore, measurements can be taken over the entire axial width of the outer diameter surface 12 of the outer ring 10, or over the entire area excluding the chamfered region, thus enabling accurate ultrasonic flaw detection. [Explanation of Symbols]

[0044] 1, 1A, 1B, 1C bearings 5 Magnets 6. Retaining member 7. Wing bolt 10 Outer ring 11 Inner surface 12 Outer diameter surface 15 Inner circle 16 Inner diameter surface 17 Rolling element 20 motors 30 Ultrasonic probe 35 Probe holder 40,40A,40B,40C Claw part 41, 41A, 41B, 41C Bearing Chucks 45 Mounting components 45d outer diameter 47 Stretching section 47A Main body 47B Tip 50 fixed rod 60 Chuck for fixing rod 100 round bar 110 Chuck for steel bars 120 motor 130 Ultrasonic probe 135 Probe holder C axis DA,DB,DC diameter

Claims

1. An apparatus for evaluating the cleanliness of steel materials constituting a bearing using ultrasonic testing, A bearing chuck connected to the output shaft of the motor and for fixing the bearing, The system comprises an ultrasonic probe positioned opposite the outer diameter surface of the bearing and moving along the outer diameter surface in a direction parallel to the output shaft, The bearing chuck comprises a mounting member fixed to the output shaft and a plurality of claws supported by the mounting member and arranged in the circumferential direction. The aforementioned claw portion supports the bearing from the inner diameter side, An ultrasonic flaw detection device for a bearing, characterized in that the radial position of the claw portion is supported by the mounting member so as to be movable in accordance with the inner diameter of the bearing.

2. Furthermore, it includes a probe holder that holds the ultrasonic probe, The ultrasonic flaw detection apparatus for a bearing according to claim 1, characterized in that the mounting position of the bearing to the bearing chuck is restricted so that the ultrasonic probe and the probe holder do not come into contact with the bearing chuck.

3. The bearing ultrasonic flaw detection apparatus for a bearing according to claim 1 or 2, characterized in that the bearing is supported in a cantilevered manner by the bearing chuck.

4. The bearing chuck is characterized in that it has an extension portion that is attached to the jaw portion and extends in a direction away from the mounting member, and the bearing is supported by the jaw portion via the extension portion, as described in claim 1 or 2.

5. By making the outer diameter of the claw portion smaller than the outer diameter of the mounting member, a stepped portion is formed between the claw portion and the mounting member. The ultrasonic flaw detection apparatus for a bearing according to claim 1 or 2, characterized in that a bearing is arranged in the stepped portion.

6. The ultrasonic flaw detection apparatus for a bearing according to claim 1 or 2, characterized in that at least an outer ring is used as the bearing, and the inner diameter surface of the outer ring of the bearing is fixed to the bearing chuck.

7. The ultrasonic flaw detection apparatus for a bearing according to claim 1 or 2, characterized in that at least an inner ring is used as the bearing, and the inner diameter surface of the inner ring of the bearing is fixed to the bearing chuck.

8. The bearing consists of at least an outer ring, an inner ring, and rolling elements, and the inner diameter surface of the pre-assembled inner ring of the bearing is fixed to the bearing chuck. The ultrasonic flaw detection device for a bearing according to claim 1 or 2, characterized by having a fixing member that suppresses the relative rotation between the outer ring and the inner ring.

9. The ultrasonic flaw detection apparatus for a bearing according to claim 8, characterized in that the fixing member is a magnet that connects and fixes the outer ring and the inner ring.

10. The ultrasonic flaw detection apparatus for a bearing according to claim 8, characterized in that the fixing member comprises a retaining member disposed on the axial end face of the outer ring and the inner ring opposite to the mounting member side, and a wing bolt that fastens the mounting member and the retaining member in a direction that brings them closer together to fix the outer ring and the inner ring.

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