Sliding rotation member for toroidal continuously variable transmission and evaluation method

A method of:

• using at least one of an input disk and output disk of a toroidal continuously variable transmission as a rolling member;
• immersing an examination surface to be examined of the rolling member and a probe for ultrasonic flaw detection disposed opposite to the examination surface into an ultrasonic wave transmission medium;
• rotating the rolling member around an axial line;
• moving the probe for ultrasonic flaw detection forwards and backwards in a direction along the axial line in a section including the axial line of the rolling member;
• scanning the rolling member and the probe with respect to each other along a shape of the examination surface;
• propagating an ultrasonic wave to the rolling member from the probe via the medium;
• and evaluating defects which exist in the examination surface and an inner portion of the rolling member based on a waveform of ultrasonic echo reflected from the rolling member, comprising the steps of:
• combining and using a first method of using either a surface wave method or angle wave method to scan the examination surface in a range right under the surface, and a second method of using either the angle wave method or a normal wave method to scan said examination surface right under the surface, and detecting a flaw within a depth range twice a maximum shear stress depth Zo;
• and
• judging the rolling member to be rejected, when a square root length of the detected defect is 0.05 mm or more.

A toroidal continuously variable transmission comprising:

• an input disk disposed on an input shaft;
• an output disk disposed on an output shaft;
• and a power roller bearing which includes an inner ring, an outer ring and a plurality of rolling members, in which said inner ring is engaged in said input disk and output disk and which transmits a power of said input shaft to said output shaft,
• wherein at least one of said input disk and output disk includes a disk center hole through which said input shaft or output shaft is passed, and does not include a defect exceeding 0.20 mm in terms of a square root length in a portion of a range which extends outwards in a radius direction from an inner peripheral surface of the disk center hole by a distance of ½ or less of a width of an end surface in a direction crossing at right angles to an axial line of the disk center hole, and in a direction along the axial line of the disk center hole from the end surface, in a depth of ⅓ or less of a disk width dimension.

A toroidal continuously variable transmission comprising:

• an input disk disposed on an input shaft;
• an output disk disposed on an output shaft;
• and a power roller bearing which includes an inner ring, an outer ring and a plurality of rolling members, in which said inner ring is engaged in said input disk and output disk and which transmits a power of said input shaft to said output shaft,
• wherein at least one of the inner ring and outer ring of said power roller bearing includes a tilting/rolling shaft hole through which a tilting/rolling shaft is passed, and does not include a defect exceeding 0.20 mm in terms of a square root length in a portion of a range which extends outwards in a radius direction from an inner peripheral surface by ½ or less of a distance to an inner peripheral surface of the tilting/rolling shaft hole from an inner edge groove of a rolling groove in an end surface, and
• in a direction along an axial line of the tilting/rolling shaft hole from the end surface, in a depth of ½ or less of a width dimension of the inner ring/outer ring.

A method of:

• using at least one of an input disk and output disk of a toroidal continuously variable transmission as a rolling member;
• immersing an examination surface to be examined of the rolling member and a probe for ultrasonic flaw detection disposed opposite to the examination surface into an ultrasonic wave transmission medium;
• rotating the rolling member around an axial line;
• moving the probe for ultrasonic flaw detection forwards and backwards along the axial line in a section including the axial line of the rolling member;
• scanning the rolling member and the probe with respect to each other along a shape of an end surface in a vertex of the disk as the examination surface;
• propagating an ultrasonic wave to the rolling member from the probe via the medium;
• and evaluating defects which exist in the examination surface and an inner portion of the rolling member based on a waveform of ultrasonic echo reflected from the rolling member, comprising the steps of:
• combining and using a first method of using either a surface wave method or angle wave method to scan the examination surface in a range under the examination surface, and a second method of using either the angle wave method or a normal wave method to scan the examination surface under the surface, and detecting a flaw in a direction along the axial line of a disk center hole from said end surface, in a depth of ⅓ or less of a disk width dimension, in a direction crossing at right angles to the axial line of the disk center hole, and in a range of ½ or less of a width of the end surface;
• and
• judging the rolling member to be rejected, when the defect detected in a portion of a range extending outwards in a radius direction from an inner peripheral surface of said disk center hole exceeds 0.20 mm in terms of a square root length.

A method of:

• using at least one of an inner ring and outer ring of a power roller bearing as a rolling member;
• immersing an examination surface to be examined of the rolling member and a probe for ultrasonic flaw detection disposed opposite to the examination surface into an ultrasonic wave transmission medium;
• rotating the rolling member around an axial line;
• moving the probe forwards and backwards along the axial line in a section including the axial line of the rolling member;
• scanning the rolling member and the probe with respect to each other along a shape of an end surface as the examination surface on a side including a rolling groove;
• propagating an ultrasonic wave to the rolling member from the probe via the medium;
• and evaluating defects which exist in the examination surface and an inner portion of the rolling member based on a waveform of ultrasonic echo reflected from the rolling member, comprising the steps of:
• combining and using a first method of using either a surface wave method or angle wave method to scan the examination surface in a range right under the surface, and a second method of using either the angle wave method or a normal wave method to scan said examination surface right under the surface, and detecting a flaw in a direction along the axial line of a tilting/rolling shaft hole from said end surface, in a depth of ½ or less of a width dimension of said inner/outer ring, and in a range of ½ or less of a distance to the inner peripheral surface of the tilting/rolling shaft hole from an inner edge groove of a rolling groove in the end surface;
• and
• judging the rolling member to be rejected, when the defect detected in a portion of a range extending outwards in a radius direction from an inner peripheral surface from said tilting/rolling shaft hole exceeds 0.20 mm in terms of a square root length.

A method of:

• immersing a sliding rotation member which is rotatably supported by a support shaft in a toroidal continuously variable transmission and slid on another member for use together with an ultrasonic probe into a transmission medium;
• allowing an ultrasonic wave to be incident upon the sliding rotation member from the ultrasonic probe via the transmission medium;
• and evaluating defects existing in an examination surface and an inner portion of the sliding rotation member based on a waveform of ultrasonic echo reflected from the sliding rotation member, said method comprising:
• (a) a step of using at least one of a surface wave method and angle wave method to scan the examination surface of the sliding rotation member and a portion right under the examination surface;
• (b) a step of defining a maximum shear stress depth generated inside the sliding rotation member at a maximum deceleration time of the toroidal continuously variable transmission as a symbol Z0, and using at least one of the angle wave method and a normal wave method to scan a portion of a depth from the examination surface which is twice the depth Z0;
• and
• (c) a step of defining a size of the defect obtained in accordance with a shape of the defect as a square root length, judging the sliding rotation member to be rejected, when said square root length of the defect detected by said steps (a) and (b) is 0.05 mm or more, and judging the sliding rotation member to be accepted, when said square root length of the defect detected in the steps (a) and (b) is less than 0.05 mm.