JPH0731163B2 - Ultrasonic flaw detection system for structural member balls - Google Patents

Description

The present invention relates to an ultrasonic flaw detector for a structural member ball.

[Conventional technology]

Regarding the defects on the surface and inside of the balls for structural members used for bearing members, wear resistant members, sliding members, etc.
Conventionally, it has been performed by X-ray inspection, zycro inspection, or visual inspection with a microscope and the naked eye. However, these inspections require a great deal of time because the balls for the structural members must be manually rotated, and it is also difficult to inspect the entire peripheral surface.

Therefore, the applicant has previously proposed an ultrasonic inspection method and apparatus for structural member balls that overcomes the above-mentioned drawbacks of the prior art (Japanese Patent Application No. 63-44000 (Japanese Patent Publication No. 6-25756)).

[Problems to be Solved by the Invention] The present invention has an object to further enhance the practicality of the previously proposed ultrasonic flaw inspection device for a structural member ball.

[Means for Solving the Problems]

According to the present invention, a ball drive unit is formed by combining two sets of a shaft portion and two rollers having a circular cross section perpendicular to the shaft portion, and the shaft portion and the roller of the ball drive portion are made of ceramics. And a ball driving roller for rotating the ball by placing the structural member ball thereon and rotating the roller of the ball driving unit, and transmitting ultrasonic waves to the ball. Then, there is provided an ultrasonic flaw detection device for a structural member ball, which is provided with an ultrasonic flaw detection probe for flaw detection of the ball.

In the present invention, the shaft portion is composed of a shaft that holds the roller and a bearing that supports the shaft.

Further, the ball driving roller is configured such that the balls for the structural member of the inspection object can be placed by combining the rollers forming the ball driving unit.

As described above, the basic structure of the ball driving unit of the present invention is a combination of two sets of the shaft portion and two rollers having a circular cross section perpendicular to the shaft portion. Part or a conical surface part and a shaft and a shaft part composed of a bearing are combined, a shaft and a spherical surface part or a conical surface part are integrally manufactured and borne, and a ball for driving a ball For example, it is a combination of a roller composed of two discs each having a curved surface or a tapered surface only in the roller portion and a shaft portion composed of a shaft and a bearing.

More specifically, for example, in FIG. 2 conceptually showing an example of the ball driving portion, it has two spherical portions having the same outer diameter, and a part of the spherical portion is cut to join the cross sections thereof. By combining two sets of the two rollers 11 and the shaft 12 which are supported and supported by the bearing 13, the ball driving roller
The reference numeral 30 designates a ball mounting portion 31 which is a concave portion formed at the joint portion of the spherical cross section of the four rollers so that the structural member balls can be mounted thereon. For driving a ball, two conical parts are provided, two conical parts are tapered and the two cross-sections are joined to each other, and two sets of two rollers 11 and a shaft 12 are combined and supported by a bearing 13. The roller 30 is one in which a ball for a structural member can be placed on a ball placing portion 31 of a concave portion formed in the conical portion of four rollers, and two rollers each having a different diameter in FIG. Two rollers 11 and a shaft 12 each having a spherical surface portion and cutting a part of the spherical surface portion to join the cross sections.
The ball driving roller 30 is formed by combining two sets of the above and the above and is supported by the bearing 13. The ball driving roller 30 is a ball mounting portion of a concave portion formed at the joint of the spherical cross sections of the four rollers.
The structure 31 can be mounted with a ball for a structural member.

Of these ball driving parts, the ball driving roller in the ball driving part is in contact with the balls for the structural member of the device under test at at least two points, and the cross sections perpendicular to the shaft part at each contact point have different outer diameters. The ball drive unit (see Fig. 4), which has a circular shape, shifts the center of rotation of the ball while rotating in a fixed direction, so that the entire circumference of the ball can be automatically inspected. Very preferable.

In the present invention, the ball for the structural member of the object to be inspected is placed on the ball driving roller, the roller constituting the ball driving section is rotated, and the frictional force between the ball driving roller and the ball is increased. The ball is rotated at a predetermined speed by the ultrasonic probe and an ultrasonic flaw detection probe is arranged so as to face the ball, and ultrasonic waves are transmitted to the rotating ball by the probe, and the entire circumference of the ball is transmitted. It is to detect the surface.

In this case, in order to detect minute defects on the surface of the ball and the vicinity of the surface of the ball, which have the greatest adverse effect on the balls for the structural member, in particular, minute defects of 100 μm or less, the rotation axis of the ball should be kept constant without being eccentric Need to This is because if the rotation axis of the ball is eccentric, the ultrasonic echo reflected from the ball will fluctuate drastically on the CRT, making it difficult to accurately detect a minute defect waveform due to a minute defect.

There are various possible methods for preventing the eccentricity of the rotating shaft of the structural member ball mounted on the ball driving roller as described above. Generally, the shaft portion of these devices, their bearings, rollers, etc. are protected. Since it is usually made of stainless steel due to rust, the ultrasonic flaw detector for this structural member ball developed by the applicant was also initially made of stainless steel. However, the eccentricity of the rotary shaft of the ball mounted on the ball drive unit during long-term use is mainly due to wear of the ball drive unit, particularly the shaft unit including the shaft and the bearing, and thereby the ball for the structural member. It was found that the microdefects in 1) could not be detected accurately.

In the device of the present invention, the shaft portion of the ball drive portion and the roller are integrally formed of ceramics to prevent eccentricity of the rotary shaft of the structural member ball mounted on the ball drive roller. In a normal drive rotating shaft, it is generally slightly eccentric, but if the eccentricity of the rotating shaft of the structural member ball is 0.7 mm or less, preferably 0.5 mm or less, the surface of the ball and the vicinity of the surface There is no major obstacle to the detection of micro defects.

The ball drive unit of the present invention is configured by combining two sets of a shaft portion including a shaft and a bearing that supports the shaft, and two rollers having a circular cross section perpendicular to the shaft portion. The roller is supported by the shaft. In this case, the shaft and the roller are integrally formed. At least the shaft portion of the ball driving portion in the present invention, that is, the shaft supporting the roller and the bearing are formed of ceramics. The roller may be formed of ceramics or various other materials such as rubber, metal, and plastics. When the roller is made of ceramics, it may be formed integrally with the shaft, or it may be molded separately and integrated with an adhesive or the like, or it may be held on the shaft by a bonding tool and driven. It may be done. Preferably, the shaft of the ball drive unit and the roller are integrally formed of ceramics. This is because the ultrasonic flaw detection inspection of micro defects in the balls for structural members is stable and the accuracy of defect detection is high.

The ceramics used for the ball driving section may have a hardness higher than that of stainless steel, and particularly wear resistance,
From the viewpoint of corrosion resistance, zirconia, silicon nitride, alumina, silicon carbide and the like having a Knoop hardness of 1200 kg / mm ² or more are preferable.

The ball for a structural member to be subjected to the ultrasonic flaw detection of the present invention is used for a bearing member, a wear resistant member, and a sliding member, and its material can be ceramic or metal, and is not particularly limited. However, in the case of a ceramic structural member ball, accurate detection of microscopic defects on the surface of the ball and in the vicinity of the surface greatly affects its reliability, so that it is particularly targeted for the device of the present invention. It is effective.

As the ceramic balls, since high strength and high hardness characteristics such as bearing members, wear resistant members and sliding members are required, those made of silicon nitride, silicon carbide, zirconia or alumina are preferably used.

Although water is generally used as the ultrasonic wave transmission medium in the ultrasonic flaw detection inspection, other oily liquids such as turbine oil and cylinder oil can also be used.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to this embodiment.

Embodiment 1 FIG. 1 is a cross-sectional explanatory view showing an embodiment of the ultrasonic flaw detector according to the present invention.

In Figure 1, two diameters 10mm held by the shaft 12
Two sets each of which forms a ball driving roller 30 having a shape in which a part of a roller 11 having a spherical portion of (φ) is cut and the cross sections thereof are joined are made of zirconia integrally with a shaft. The portion of the bearing 13 supporting the shaft 12 was also made of zirconia.

The Knoop hardness of the test piece manufactured in the same lot as that of the shaft and the like was 1200 kg / mm ² . In addition, the shaft tip and bearing were finished to a surface roughness of Rmax 2 μm or less.

The ball driving roller 30 is attached to the gear 14 and the driving belt.
A ball driving motor 16 for rotating the probe 17 through the probe 15, a probe mounting arm 18 for fixing the probe 17, and a probe for rotating the probe 17 around the ceramic ball 10 via the probe mounting arm 18. A ball ultrasonic testing device for structural members, including a tentacle drive motor 19, was installed in a water tank 20. Further, an appropriate amount of water was put in the water tank 20. In FIG. 1, 24 is a mount for the ball drive motor 16 and the probe drive motor 19, 25 is a mount for the ball drive roller 30, and 26 is a mount.
Indicates a structural member.

With the ultrasonic inspection equipment set as above,
mm silicon nitride ball 10 is mounted on the ball mounting portion 31 of the ball driving roller 30, and an ultrasonic testing probe 17 having a flaw detection frequency of 30 MHz, a transducer diameter of 5 mm, and a focal length of 10 mm is searched. The probe 17 was fixed to the arm 18 and the probe 17 and the ultrasonic flaw detector 21 were connected by a cable 22. The position of the probe 17 was adjusted so that the distance between the probe 17 and the surface of the ball 10 was 10 mm, and the ultrasonic waves were incident perpendicularly to the surface of the ball 10. Also, ultrasonic waves are transmitted from the probe 17 and the surface waves are CR.
It was located at the center of T23.

Next, the ball drive motor 16 was rotated, and the fluctuation of the surface wave on the CRT was measured while rotating the ball 10 very slowly at a rotation speed of about 10 rpm. As a result, the amount of eccentricity is 0.50 mm
Met.

Next, after removing the ball 10 and rotating the ball 10 at 1000 rpm for 1000 hours, the ball 10 was placed again and the eccentricity of the ball rotation was measured in the same manner as above. As a result, the amount of eccentricity is 0.50 mm
Had not changed at all.

Example 2 The ball rotation was performed in the same manner as in Example 1 except that the roller 11 and the shaft 12 were integrally molded with silicon nitride having a Knoop hardness of 1350 kg / mm ² instead of zirconia, and the bearing was also made of silicon nitride. The eccentricity of the shaft was measured.

As a result, as in Example 1, the initial eccentricity amount and the eccentricity amount after 1000 hours were both 0.30 mm, which was unchanged.

Comparative Example The eccentricity was measured in the same manner as in Example 1 except that the shaft and the roller were integrally made of stainless steel instead of zirconia and the bearing was also stainless steel. As a result, the initial amount of eccentricity was 0.35 mm, but the amount of eccentricity after rotating for 1000 hours changed to 0.80 mm, and the CRT waveform could not be accurately observed.

〔The invention's effect〕

According to the ultrasonic flaw inspection apparatus for a ball for a structural member of the present invention, there is an advantage that minute defects on the surface of the ball and in the vicinity of the surface can be detected quickly, accurately, and accurately for a long time.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing an embodiment of the ultrasonic flaw detector of the present invention, FIG. 2 is a plan view showing an example of a ball drive unit used in the present invention, and FIG. 3 is a ball drive used in the present invention. FIG. 4 is a plan view showing another example of the portion, and FIG. 4 is a plan view showing still another example of the ball driving portion used in the present invention. 10 ... Ball, 11 ... Roller, 12 ... Axis 13 ... Bearing, 14 ... Gear 15 ... Driving belt 16 ... Ball drive motor, 17 ... Probe 18 ... Probe mounting arm 19 ... Probe drive motor, 20 ... Water tank 21 ... Ultrasonic flaw detector, 22 ... Cable 23 ... CRT, 24, 25 ... Stand 26 ... Structural member 30 ... Ball driving roller 31 ... Ball mounting part

Claims (2)

[Claims] 1. A shaft portion and a cross section perpendicular to the shaft portion are circular. 2
It comprises a ball drive part formed by combining two sets of two rollers, and the shaft part of the ball drive part and the roller are integrally formed of ceramics, and the balls for the structural members are mounted on the ball drive part. A ball driving roller that rotates the ball by rotating the roller of the ball driving unit; and an ultrasonic flaw detection probe that transmits ultrasonic waves to the ball to detect the ball. Ultrasonic flaw inspection equipment for balls for structural members. 2. The ultrasonic flaw detector for a structural member ball according to claim 1, wherein the ceramic has a Knoop hardness of 1200 kg / mm ² or more.