Patent ID: 9240115
Filing Date: 2016-01-19
CPC Classification: F16H,G01M,G08B

Claim Text:
1. A power transmission apparatus, comprising: a drive pulley supported on a drive shaft, a driven pulley supported on a driven shaft, a power transmission belt wound around the drive pulley and the driven pulley and containing a stress light emission material to emit light in response to an external force exerted thereon, an optical sensor disposed in face-to-face relationship with the power transmission belt to measure the light emitted by the power transmission belt, and an exchange judgment unit that judges whether or not the power transmission belt is deteriorated based on the measured value of the light detected by the optical sensor, and judges that a belt exchanging time is reached with the judgment indicating that the power transmission belt is deteriorated, the exchange judgment unit comprising a deterioration-exchange judgment section adapted to judge that the power transmission belt is deteriorated with the belt exchanging time reached at least one of the times when the measured value of the light exceeds a predetermined light emission threshold value and when the measured value of the light is varied in a predetermined light emission pattern, the power transmission belt being constituted by a toothed belt having a tooth surface and a tooth cloth provided on the tooth surface, the optical sensor being disposed in face-to-face relationship with the tooth cloth of the toothed belt, and the deterioration-exchange judgment section comprising a setting subsection, an increased light determination subsection, a pattern determination subsection, and an exchange judgment subsection, the setting subsection being adapted to set an average measured value of the light based on the measured value of the light detected by the optical sensor at the initial stage of the power transmission belt wound around the drive pulley and the driven pulley and to set the predetermined light emission threshold value with a predetermined value being added to the average measured value of the light, the increased light determination subsection being adapted to judge that the power transmission belt is deteriorated when the measured value of the light exceeds the predetermined light emission threshold value, and the pattern determination subsection being adapted to judge that there is a crack generated in the tooth cloth at a specific portion of the power transmission belt and that the power transmission belt is deteriorated when the measured value of the light at a specific portion of the power transmission belt is periodically peaked and when the measured value of the light is varied in the light emission pattern, the exchange judgment subsection being adapted to judge that the power transmission belt reaches the belt exchanging time when at least one of the increased light determination subsection and the pattern determination subsection judges that the power transmission belt is deteriorated.