Detecting flaws formed in surfaces of rotating members with ultrasonic waves
First Claim
1. A method of detecting a defect formed in a surface of a rotating member having a circular cross-section with the aid of a focusing-type probe for emitting an ultrasonic wave toward the rotating member and receiving an ultrasonic wave reflected from the rotating member, comprising the steps of:
- setting the focusing-type probe with respect to the rotating member in an ultrasonic wave propagating medium such that a center axis (a) of the probe is displaced from a normal axis (b) which passes through a center axis of the rotating member and extends parallel to said center axis of the probe by such a displacement about (x) that the ultrasonic wave is made incident upon the rotating member substantially at a critical angle of reflection, such that a portion of the ultrasonic wave is refracted thereby to propagate substantially along a surface of the rotating member as a surface wave, said probe being set at a distance from the surface of the rotating member which is substantially equal to the focal length of the ultrasonic wave emitted from the focusing-type probe, such that the ultrasonic wave to be projected from the probe is focused on the surface of the rotating member;
projecting the ultrasonic wave from the probe toward the rotating member; and
receiving an ultrasonic wave reflected from a defect formed in the surface of the rotating member.
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Accused Products
Abstract
In a method of detecting defects formed in a surface or in the vicinity thereof of a ball of a bearing by means of an ultrasonic wave, the ball and a probe for projecting an ultrasonic wave toward the ball and receiving an ultrasonic wave reflected from the detects are arranged in water in such a manner that a center axis of the probe is deviated from a normal axis of the ball which passes through a center of the ball and extends in parallel with the center axis of the probe by such a displacement amount that the ultrasonic wave refracted by the ball propagates along the surface of ball. The ball is rotated about a horizontal axis perpendicular to the normal axis, and the ball and probe are rotated relative to each other about a center axis of the ball which is perpendicular both to the normal axis and horizontal axis of the ball, so that the whole surface of the ball is scanned automatically with the ultrasonic wave.
36 Citations
20 Claims
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1. A method of detecting a defect formed in a surface of a rotating member having a circular cross-section with the aid of a focusing-type probe for emitting an ultrasonic wave toward the rotating member and receiving an ultrasonic wave reflected from the rotating member, comprising the steps of:
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setting the focusing-type probe with respect to the rotating member in an ultrasonic wave propagating medium such that a center axis (a) of the probe is displaced from a normal axis (b) which passes through a center axis of the rotating member and extends parallel to said center axis of the probe by such a displacement about (x) that the ultrasonic wave is made incident upon the rotating member substantially at a critical angle of reflection, such that a portion of the ultrasonic wave is refracted thereby to propagate substantially along a surface of the rotating member as a surface wave, said probe being set at a distance from the surface of the rotating member which is substantially equal to the focal length of the ultrasonic wave emitted from the focusing-type probe, such that the ultrasonic wave to be projected from the probe is focused on the surface of the rotating member; projecting the ultrasonic wave from the probe toward the rotating member; and receiving an ultrasonic wave reflected from a defect formed in the surface of the rotating member. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An apparatus for detecting a defect formed in a surface of a rotating member having a circular cross-section with the aid of an ultrasonic wave comprising:
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a focusing-type probe for emitting a focused ultrasonic wave toward the rotating member and receiving an ultrasonic wave reflected from the defect; first supporting means for supporting the rotating member rotatably about a center axis thereof; second supporting means for supporting said focusing-type probe with respect to the rotating member in such a manner that a center axis (a) of the probe is displaced from a normal axis (b) which passes through the center axis of the rotating member and extends parallel to said center axis of the probe by such a predetermined displacement about (x) that the ultrasonic wave is made incident upon the rotating member substantially at a critical angle of reflection, such that a portion of the ultrasonic wave is refracted thereby to propagate substantially along a surface of the rotating member as a surface wave, said probe being set at a distance from the surface of the rotating member which is substantially equal to the focal length of the ultrasonic wave emitted from the focusing-type probe, such that the ultrasonic wave projected from the probe is focused on the surface of the rotating member; and means for containing an ultrasonic wave propagating medium in which said probe, said first supporting means and said second supporting means are immersed. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification