| 摘要 |
PURPOSE:To improve the resistance against vibration and shock and enhance the detecting performance, by a method wherein an electromagnetic pickup, forming a piston ring sensor, is incorporated in a cylinder oil filling check valve, resulting in the formation of the device into a simple, small and compact type and an integrated structure. CONSTITUTION:An electromagnetic pickup body 21 is inserted from a base end side into a screwed hole 18 for holding a retainer cylinder member 15 and is screwed in by the use of an undercut 24 for integral mounting. Thereby, this process causes oil passages to be formed with a projection 22 at the tip and screw projections 23 on the peripheral side between the body 21 and the screwed hole 18. A yoke lever 27, passing the centers of a bored hole 17 and an oil filling hole 5 with its forward end surface facing a liner wall surface 2, forms a magnetic circuit together with a permanent magnet 28. Since a magnetic flux extends into a cylinder from the wall surface 2, the magnetic flux is cut by a piston ring which slides and frictionally passes along the wall surface in a manner to make press contact with the wall surface 2. This causes a detecting coil 26 to fetch a change in the magnetic flux corresponding to the state of the piston ring crossing the front end surface of the yoke lever 27. |
