| 摘要 |
PURPOSE:To prevent the infiltration of a water drop from the spacing between a holder and cap and to make improvement in the reliability of the sensor by widening the clearance between the stepped surface between the small-diameter part and large- diameter part on the base end side of the holder and the front end of the cap. CONSTITUTION:The distance of the clearance S between the stepped surface 10 of the large-diameter part of the holder 1 and the small-diameter part on the base end and the front end of the cap 5 is widened to, for example, about 3mm, and further, the angle of the stepped surface 10 with the small-diameter part on the base end side of the holder 1 is set at, for example, about 107 deg. to form the curved shape having a smooth angle part. The water drop is generally liable to be stuck to the clearance S by surface tension if the distance of the clearance S is small. The clearance S between the holder 1 and the cap 5 is, thereupon, widened, by which the sticking of the water drop between the stepped surface part 10 of the holder 1 and the front end of the cap 5 is prevented. The infiltration of the water drop into the sensor is prevented in this way and the degradation in the electromotive force of the sensor by the infiltration of the water drop into the sensor is prevented, by which the improvement in the reliability of the sensor is made. |
