CONTACT ANGLE MEASURING APPARATUS AND CONTACT ANGLE MEASURING METHOD

PROBLEM TO BE SOLVED: To provide a contact angle measuring apparatus and a contact angle measuring method that enable accurate measurement of a radial contact angle.SOLUTION: There is provided a contact angle measuring apparatus capable of measuring a radial contact angle of a ball which comes into contact, at two points, with a raceway surface 111 formed on a bearing ring 11 of a ball bearing. The contact angle measuring apparatus comprises: a measurement jig 20 which has a same circular cross section as a cross section passing through the center of the ball, and which has, on an outer peripheral surface thereof, conductive parts 25 and 26 coming into contact with the raceway surface 111 at one point and nonconductive parts 22a and 23a other than the conductive parts 25 and 26; a power source unit 28 for applying a voltage between the conductive parts 25 and 26 and the bearing ring 11; a detector 29 for detecting conduction between the conductive parts 25 and 26 and the bearing ring 11 that is generated by the contact of the conductive part 25 or 26 with the raceway surface 111; and a measuring device 30 for measuring a rotation angle of the measurement jig 20 when the detector 29 detects the conduction by rotating the measurement jig 20 brought into contact with the raceway surface 111, around a center line of the measurement jig 20. 【課題】ラジアル接触角を正確に測定できる接触角測定装置及び接触角測定方法を提供する。【解決手段】玉軸受の軌道輪１１に形成された軌道面１１１に２点で接触する玉のラジアル接触角を測定する接触角測定装置は、玉の中心を通る断面と同一の円形断面を有しかつ外周面に軌道面１１１と１点で接触可能となる導電部２５，２６及び当該導電部２５，２６以外の非導電部２２ａ，２３ａを有する測定用治具２０と、導電部２５，２６と軌道輪１１との間に電圧を印加する電源部２８と、導電部２５，２６が軌道面１１１に接触することで生じる導電部２５，２６と軌道輪１１との間の導通を検出する検出器２９と、軌道面１１１に接触させた測定用治具２０を測定用治具２０の中心線回りに回転させて検出器２９が前記導通を検出した際の測定用治具２０の回転角度を測定する測定器３０と、を備えている。【選択図】図２