Ngk Insulators, Inc.

Koji Fushimi

Keiji Kawasaki

Shigeo Nishioka

Yukihito Ichikawa

Kazuhiro Konishi

An ultrasonic testing method for detection of flaws in a ball-shaped material to be tested using an ultrasonic probe, wherein a test frequency f (MHz) of the probe and a radius of curvature r (mm) of a tip portion of the probe satisfy the relationship 50 mm.ltoreq.r.sqroot.f.ltoreq.60 mm, and wherein the radius of curvature r (mm) of the tip portion and the diameter D (mm) of an oscillator of the probe satisfy the relationship 0.35 mm.ltoreq.D/r.ltoreq.0.50 mm. The method enables detection of surface and internal flaws in materials, particularly ceramic ball hearings having a diameter ranging from several tens of millimeters down to 10 mm or below.

Ultrasonic testing method for balls

A ceramic guide pin having a guide portion, wherein at least the guide portion has a surface so shaped, microscopically, that top portions of outwardly projected portions of the surface are in the shape of gently curved surfaces. The ceramic guide pin can be produced by a process which comprises the steps of preparing a shaped body of a ceramic guide pin by forming or machining in dimensions calculated from the desired finished dimensions and a firing shrinkage allowance factor, sintering said shaped body, and subjecting the sintered body to barrel polishing.

Ceramic guide pin

An ultrasonic testing method for detecting flaws of balls for structural members comprises rotating a ball to be tested in an ultrasonic wave transmitting medium. At least two focus-type ultrasonic probes are provided and arranged so as to cover nonoverlapping flaw-detecting regions on and/or inside the ball. Flaws in the ball are detected by sending ultrasonic waves from the probes toward the ball. An apparatus for detecting flaws of balls comprises a ball holding portion for rotatably holding the ball to be tested, at least two focus-type probes for detecting flaws and at least two probe mounting portions for mounting the probes thereof so that respective axes of the probes are each capable of being set eccentrically relative to the center of the ball and wherein the focal positions of the probes are variable.

Ultrasonic testing method for detecting flaws of balls for structural

An immersion type automatic ultrasonic testing apparatus for detecting flaws of balls comprising a tank for containing a liquid medium of transmitting ultrasonic wave, a ball rotating device for rotating a ball to be tested, an ultrasonic flaw detection device for detecting flaws in the ball while swiveling a probe around the ball rotated by the ball rotating device or rotating the ball spirally by the ball rotating device with or without swiveling the probe, and a ball feeding and removing device for feeding the ball to the position of the ball rotating device and removing the tested ball from the ball rotating device to a predetermined position. The ball feeding device comprises a holding device having an air cylinder and a tip with a pair of holder claws and a pair of side support claws for holding the ball.

Automatic ultrasonic testing apparatus for detecting flaws of structural

An immersion type automatic ultrasonic testing apparatus for detecting flaws of balls comprising a tank for containing a liquid medium of transmitting ultrasonic wave, a ball rotating device for rotating a ball to be tested, an ultrasonic flaws detection device for detecting surface flaws in the ball while swiveling a probe around the ball rotated by the ball rotating device or rotating the ball spirally by the ball rotating device with or without swiveling the probe, and a ball feeding device for feeding the ball to the position of the ball rotating device. The ball feeding device comprises an air cylinder for holding the ball by suction at the tip thereof. For the suction holding of the ball at the tip of the air cylinder, a level regulating device is additionally provided for setting a level of the liquid medium of transmitting ultrasonic wave in the tank wherein the ball rotating device and the ultrasonic flaws detection device are placed.

Immersion type automatic ultrasonic testing aparatus for detecting flaws

An ultrasonic testing method for detection of flaws in a material to be tested having a curved surface portion by use of an ultrasonic probe, wherein a center axis of curvature of the curved surface portion of the material to be tested and the center axis of the probe are set in an eccentric relationship so that the angle of refraction of an ultrasonic wave is 90.degree., and the probe comprises a tip portion having a curved surface of the same kind as the curved surface portion of the material to be tested and a radius of curvature of from 1.0 to 3.0 times the radius of curvature of the curved surface portion of the material to be tested. The method enables detection of internal flaws in, particularly, a spherical or cylindrical body formed of a ceramic and used as a bearing member.

Ultrasonic testing method

An ultrasonic flaw detecting method able to detect defects of structural balls arranged in an ultrasonic transmitting medium with the aid of reflecting ultrasonic echoes transmitted from an ultrasonic flaw detecting probe immersed in the ultrasonic transmitting medium. The ball to be tested is arranged on two sets of ball driving rollers and the driving rollers are driven to rotate the ball during the test. An ultrasonic flaw detecting apparatus comprises ball driving rollers each including a shaft portion and a ball driving portion having a circular shape in a section perpendicular to the shaft portion to rotate the ball arranged on the ball driving rollers when the ball driving rollers are rotated, and an ultrasonic flaw detecting probe adapted to rotate about the ball for transmitting ultrasonic waves to the ball to scan defects of the ball.

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Gifu, Japan

Koji Fushimi