JP2003207488A - Ultrasonic flaw detection method and apparatus for inner surface of bearing outer race - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To detect a surface defect on an inner diameter portion of an outer race while keeping a finished product bearing in an assembled state, and to make an ultrasonic transmission medium such as water or oil penetrate into the finished product bearing. Provided is an ultrasonic flaw detection method capable of detecting a surface defect without causing interference echo due to grease or the like sealed in a seal bearing, and a probe unit therefor. An outer race (17) of a finished bearing (16) is provided.
The probe 14 for ultrasonic flaw detection is arranged at a distance from the ultrasonic incidence point on the outer surface of the
6 is placed in the ultrasonic transmission medium 4 such as water or oil, and an ultrasonic beam is emitted from the probe 14 to the outer race 17 while an ultrasonic echo reflected from the outer race 17 is generated. The probe 14 detects the surface flaw 21 on the inner surface of the outer race 17 by receiving the signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic flaw detection method for the surface of the inner diameter portion of the outer race of a bearing, and more particularly to an ultrasonic flaw detection method for the surface of the inner diameter portion of the outer race of an assembled finished bearing.

[0002]

2. Description of the Related Art Conventionally, as an ultrasonic flaw detection method for detecting surface flaws on the inner diameter portion of the outer race ring of a bearing by detecting flaws, the ring material after rolling in the steel making process of the bearing ring steel is put in water or on a table. There is known a vertical flaw detection method of flaw detection of the bearing ring material by transmitting ultrasonic waves from the outer peripheral surface of the ring material to the inside.

Further, Japanese Patent Laid-Open No. 11-337530 discloses an ultrasonic flaw inspection method for inspecting inner surface defects of an outer race ring of a bearing. A flaw detection method performed by flaw detection is disclosed.

By the way, when the inner race of the finished product bearing is immersed in a water layer or an oil layer, which is an ultrasonic transmission medium, for ultrasonic flaw detection, water or oil enters the inside of the bearing, so that the bearing is in a finished product state. Then, such an ultrasonic flaw detection method cannot be applied.

The side surface of the ball 19 of the bearing is sealed,
In the case of a sealed bearing in which the grease 24 is enclosed around the steel balls 19, the grease 24 is enclosed inside the bearing 16, and if flaw detection is performed in the state of the finished product bearing by the conventional method, the inner surface of the outer race 17 is detected. Due to the unevenness of the grease 24 enclosed on the 27, as shown in (a) measurement schematic diagram, (b) enlarged schematic diagram, and (c) echo waveform diagram of FIG. 7, it is emitted from the probe 14. The ultrasonic beam 22 is applied to the outer surface 27 of the outer race 17.
Is incident on the outer race 17 and is reflected by a defect due to a flaw in the inner surface portion to generate a defect echo 30, and is further reflected on the inner surface 26 to generate a surface echo 29. Grease 2 incident on grease 24
A large number of disturbing echoes 31 are generated due to the unevenness of the presence of the grease 24 caused by being reflected on the surface of No. 4. Therefore, in the case of the bearing 16 with a seal, it becomes difficult to accurately detect the flaw 21 by ultrasonic flaw detection.

Therefore, conventionally, when the outer ring race 17 is to be flaw-detected, it is necessary to disassemble the finished product bearing 16 once to leave the outer ring race 17 as a single body without the grease 24 before performing ultrasonic flaw detection. Therefore, it takes time to disassemble and assemble the finished product bearing 16 for flaw detection.

[0007]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is to detect surface defects in the inner diameter portion of the outer ring race while the finished product bearing is in the assembled state. Ultrasonic flaw detection method and ultrasonic wave detection method that can detect surface defects without invading ultrasonic transmission medium such as etc., and can detect surface defects without generating interfering echo due to the influence of grease enclosed in seal bearings. An object of the present invention is to provide a probe unit for an ultrasonic flaw detection device used in a flaw detection method.

[0008]

According to the invention of claim 1, an ultrasonic wave incident point on the outer surface of an outer race of a finished product bearing and the ultrasonic wave incident point are provided. A probe for ultrasonic flaw detection, which is spaced apart from, is placed in an ultrasonic transmission medium such as water or oil,
A bearing outer ring race characterized by detecting ultrasonic defects reflected from the outer ring race on the inner surface of the outer ring race while emitting ultrasonic waves from the probe to the outer ring race. This is a method of ultrasonic flaw detection on the inner surface of the.

According to a second aspect of the present invention, the flaw detection of the surface defects on the inner surface of the outer ring race is performed over the entire peripheral surface of the inner surface of the outer ring race. This is an ultrasonic flaw detection method.

According to the third aspect of the present invention, the position of the ultrasonic wave emitting portion of the probe is deviated from the radial direction of the bearing by a certain value or more so that the ultrasonic wave emitting direction is parallel to the radial direction of the bearing, and the probe is connected to the outer ring race. The angle of incidence on the outer surface of the outer ring race is set to a certain angle or more, and the angle of incidence on the inner surface of the outer ring race is set to a larger angle so that the inner surface of the outer ring race is closer to the bearing center side. 3. The ultrasonic flaw detection method according to claim 1 or 2, wherein the ultrasonic wave is not incident on and totally reflected.

According to the invention of claim 4, the incident angle from the ultrasonic wave incident point to the inner surface of the outer race is 80 to 90 °.

According to the invention of claim 5, a bearing having a holding groove for receiving and holding a part of the outer ring race in the radial direction of the finished product, and an ultrasonic transmission medium filling groove formed in the lower center of the holding groove. A probe unit for ultrasonic flaw detection, comprising a holding frame and an incident angle adjusting plate in which a probe for ultrasonic flaw detection is erected from the lower surface in a filling groove of the bearing holding frame and the filling groove is sealed. Is.

In the invention of claim 6, the incident angle adjusting plate is mounted on the lower surface of the bearing holding frame by a bolt so that the incident angle adjusting plate can be displaced in the longitudinal direction of the bearing holding frame, and the probe is fixed in the incident angle adjusting plate. The probe unit for ultrasonic flaw detection according to claim 6, wherein the probe unit is fixed by a tool.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view for explaining a flaw detection method for a finished product bearing of the present invention by showing a partial cross section thereof. FIG. 2 is a perspective view showing the bearing holding frame of the probe unit of the flaw detection device used in the flaw detection method of the present invention. FIG. 3 is a perspective view showing an incident angle adjusting plate of the probe attached to the lower portion of the bearing holding frame of FIG. FIG. 4 is a schematic diagram for explaining the difference in the incident angle to the inner surface of the outer race due to the displacement of the ultrasonic wave emitting portion of the probe from the center of the finished product bearing. FIG. 5 is a waveform diagram of the echo on the display according to the method of the present invention. 6A and 6B are diagrams of a probe and an ultrasonic beam, FIG. 6A is an elevation view of a focused probe and an ultrasonic beam, and an elevation view of a non-focus probe and an ultrasonic beam, and FIG. It is a bottom view and the bottom view of a focus type probe.

The ultrasonic flaw detector used in the ultrasonic flaw detection method of the present invention will be briefly described. The means of the present invention comprises a probe unit 1 and a probe 14 having an ultrasonic oscillator.
And an ultrasonic transmission medium 4 such as water or oil held in the probe unit 1. Probe unit 1
Attach the incident angle adjusting plate 3 to the bearing holding frame 2 with the bolt 1
It is attached by 5 and is integrally formed. As shown in FIG. 2, the bearing holding frame 2 comprises a shallow groove bearing holding groove 6 having a medium filling groove 5 having a bottom opening 7 at the bottom. The bearing holding groove 6 is designed according to the outer diameter of the outer race 17. Bolt holes 8 for attaching the incident angle adjusting plate 3 are provided at the bottom of the bearing holding frame 2 in front of and behind the medium filling groove 5. As shown in FIG. 3, the incident angle adjusting plate 3 has a protruding portion 9 protruding downward from the center.
And a probe 10 having a guide 10 protruding to the upper surface on one side thereof. The projection 9 is provided with two probe mounting holes 11 for mounting probes on the left and right sides, and the probe mounting holes 11 are provided on the side thereof. There is a fixture insertion hole 12 into which a probe 14 is inserted and fixed. Before and after the projecting portion 9 of the incident angle adjusting plate 3, elongated holes 13 in the front-rear direction for inserting and attaching the bolts 15 to the bottom of the bearing holding frame 2 are provided, respectively. Is guided in the front-rear direction by the guide 10 to be set to the optimum position, and then fixed to the bearing holding frame body 2 by the bolt 15.

First, as shown in FIG. 1, an ultrasonic wave transmission medium 4 such as water or oil is filled in a medium filling groove 5 in a bearing holding frame 2 assembled in the probe unit 1. Next, the finished product bearing (hereinafter referred to as “bearing”) 16 is fitted into the bearing holding groove 6 to hold the bearing 16. In this case, the liquid amount is adjusted so that the liquid surface of the ultrasonic transmission medium 4 does not come into contact with the side surface seal portion 20 of the bearing 16.

Next, the ultrasonic beam emitting position of the probe 14 is displaced from the center O of the bearing 16. The deviation amount d or the deviation amount D is the inner surface state of the outer race 17 of the bearing 16, that is, the grease 2 on the inner surface 27.
The incident angle adjusting plate 3 is moved back and forth for adjustment depending on the presence or absence of 4. A side seal portion 20 is provided on the side surface of a steel ball 19 inserted between the outer race 17 and the inner race 18 of the bearing 16, and the grease 2 is provided inside the side seal portion 20.
In the case where the grease 24 is present on the inner surface 27 of the outer ring race 17 in a sealed bearing having 4 or the like, the incident angle θ6 of the ultrasonic beam 23 on the inner surface 27 of the outer ring race 17 is set to 80 as shown in FIG. The incident angle adjusting plate 3 is moved so that the angle becomes ˜90 °, and the ultrasonic beam emitting position of the probe 14 is adjusted from the center O of the bearing 16 so that the deviation amount D is obtained. At this time, the refraction angle of the ultrasonic beam 23 entering the grease 24 at the boundary 25 between the inner surface 27 of the outer race 17 and the grease 24 is 90 °.
Thus, the ultrasonic beam 23 is used for the outer race 1
It is totally reflected at the boundary 25 between the grease 7 and the grease 24 and does not penetrate into the grease 24. Therefore, the disturbing echo 31 caused by the reflection of the ultrasonic beam in the grease 24 does not occur.

This is for the following reason. As shown in FIG. 4, when the deviation of the ultrasonic beam emitting position of the probe 14 from the center O of the bearing 16 is taken as the displacement amount d, the ultrasonic beam 22 follows the Snell's law shown in the following formula 1. Become.

## EQU1 ## Sinθ1 / Sinθ2 = C1 / C2 = constant, where C1: the speed of sound in the oil of the medium, C2: the speed of sound in the steel of the outer race of the medium

Therefore, when the displacement of the ultrasonic beam emitting position of the probe 14 from the center O of the bearing 16 is largely shifted to make the displacement amount d a larger displacement amount D, the incident angle θ1 is incident at a larger angle. The angle is θ4. At this time, according to Snell's law, the following Expression 2 is established, and therefore the refraction angle θ5 is also larger than the refraction angle θ2.

## EQU00002 ## Sin.theta.4 / Sin.theta.5 = C1 / C2 = constant

Therefore, the incident angle θ6 from the outer race 17 into the inner surface thereof is also larger than the incident angle θ3. Therefore, when the deviation amount D is increased and θ6 approaches 90 °, the ultrasonic beam 23 is totally reflected at the boundary 25 and does not enter the grease 24.

On the other hand, when the grease 24 is not present on the inner surface 27 of the outer race 17, the interference echo 31 due to the influence of the grease 24 does not occur, so that the inner surface 27 of the outer race 17 is not generated.
By adjusting the incident angle adjusting plate 3 toward the center so that the incident angle θ3 of the ultrasonic beam 23 into the inside is in the range of 45 to 70 °, and by reflecting at the flaw 21 in the inner surface portion of the outer race 17. The defect echo 31 can be accurately detected.

Further, in order to reduce the influence of the state of the inner surface of the bearing 16 such as the presence of the steel balls 19, as shown in FIG. 6, the focus probe 14b is selected as the probe 14 and the outer ring race is performed. It is assumed that the probe 14b having a focal length corresponding to the wall thickness of 17 and the water distance is selected to irradiate the ultrasonic beam 22 on the inner surface 27 of the outer race 17 of the bearing 16.

FIG. 5 shows the waveform of the inspection result obtained by eliminating the interfering echo 31 with the deviation amount d according to the present invention as a larger deviation amount D. In FIG. 5, a surface echo 29 and a defect echo 30 indicating the presence of the flaw 21 are shown on the display.

[0024]

As described above, the finished bearing is disassembled by using the method and apparatus of the present invention in the method of ultrasonically detecting defects on the inner surface of the outer race of the bearing. Without doing so, ultrasonic flaw detection can be performed efficiently, in a short time, and with high accuracy in the assembled state.

[Brief description of drawings]

FIG. 1 is a schematic view for explaining a flaw detection method for a finished product bearing of the present invention by showing a partial cross section thereof.

FIG. 2 is a perspective view showing a bearing holding frame of the probe unit of the flaw detection apparatus used in the flaw detection method of the present invention.

FIG. 3 is a perspective view showing an incident angle adjusting plate of a probe attached to a lower portion of a bearing holding frame.

FIG. 4 is a schematic diagram for explaining the difference in the incident angle to the inner surface of the outer race due to the displacement of the ultrasonic wave emitting portion of the probe from the center of the finished product bearing.

FIG. 5 is a waveform diagram of an echo according to the method of the present invention.

6A and 6B are diagrams of a probe and an ultrasonic beam, FIG. 6A is an elevation view of a focused probe and an ultrasonic beam, and an elevation view of a non-focus probe and an ultrasonic beam, and FIG. 6B is a focused probe. FIG. 3 is a bottom view of FIG.

7A and 7B are schematic explanatory views of a conventional flaw detection method for a bearing outer ring race, in which FIG. 7A is a schematic view, FIG. 7B is a partially enlarged view showing a grease pool, and FIG. 7C is an echo waveform diagram.

[Explanation of symbols]

1 probe unit 2 Bearing holding frame 3 Incident angle adjustment plate 4 Ultrasonic transmission medium 5 medium filling groove 6 Bearing retaining groove 7 Bottom opening 8 bolt holes 9 Projection 10 guides 11 Probe mounting hole 12 Probe fixture insertion hole 13 long hole 14 probes 14a Non-focus probe 14b Focus probe 15 volts 16 finished product bearings 17 outer race 18 inner race 19 steel balls 20 Side seal part 21 Defect 22 Ultrasonic beam 22a Focused ultrasonic beam 22b Non-focus type ultrasonic beam 23 Ultrasonic beam 24 Grease 25 boundaries 26 Bottom of probe 27 Inner surface 28 outer surface 29 surface echo 30 defect echo 31 jamming echo O bearing center d deviation amount D deviation amount θ1 incident angle θ2 Refraction angle θ3 incident angle θ4 incident angle θ5 Refraction angle θ6 incident angle

Claims (6)

[Claims] 1. An ultrasonic wave incident point on an outer surface of an outer ring race of a finished product bearing and an ultrasonic flaw detection probe arranged apart from the ultrasonic wave incident point in an ultrasonic wave transmission medium such as water or oil. The bearing is characterized in that the probe emits ultrasonic waves to the outer race and at the same time receives ultrasonic echoes reflected from the outer race by the probe to detect surface defects on the inner surface of the outer race. Ultrasonic flaw detection method for inner surface of outer race. 2. The ultrasonic flaw detection method for an inner surface of a bearing outer ring race according to claim 1, wherein flaw detection of surface defects on the inner surface of the outer ring race is performed over the entire circumferential surface of the inner surface of the outer ring race. 3. The position of the ultrasonic wave emitting portion of the probe is deviated from the radial direction of the bearing by a certain value or more so that the ultrasonic wave emitting direction is parallel to the radial direction of the bearing, and the ultrasonic wave from the probe to the outer surface of the outer race is By making the incident angle at the ultrasonic wave incident point a certain angle or more and making the incident angle from the ultrasonic wave incident point to the inner surface of the outer ring race a larger angle, the ultrasonic wave from the inner surface of the outer ring race to the bearing center side The ultrasonic flaw detection method according to claim 1 or 2, wherein incident light is eliminated and total reflection is performed. 4. The ultrasonic flaw detection method according to claim 3, wherein the incident angle from the ultrasonic wave incident point to the inner surface of the outer race is 80 to 90 °. 5. A bearing holding frame body having a holding groove for receiving and holding a part of a radial outer ring race of a finished product and an ultrasonic transmission medium filling groove formed in the center of a lower portion of the holding groove, A probe unit for ultrasonic flaw detection, comprising: an incident angle adjusting plate in which a probe for ultrasonic flaw detection is erected from the lower surface in the filling groove of the bearing holding frame and the filling groove is sealed. 6. The incident angle adjusting plate is attached to the lower surface of the bearing holding frame by a bolt so that the incident angle adjusting plate can be displaced in the front-rear direction of the bearing holding frame, and the probe is fixed in the incident angle adjusting plate by a probe fixture. The probe unit for ultrasonic flaw detection according to claim 6, wherein