초록 ▼

In order to obtain a reliable position determination in a hydraulic cylinder optionally exposed to hard frost, it is suggested to mount a magnetically sensitive component in the form of a Hall-effect transducer in a bore in the cylinder wall and placed between a permanent annular magnet (17) and a m

In order to obtain a reliable position determination in a hydraulic cylinder optionally exposed to hard frost, it is suggested to mount a magnetically sensitive component in the form of a Hall-effect transducer in a bore in the cylinder wall and placed between a permanent annular magnet (17) and a magnetically conducting sheet (14). In the middle of the bore a magnetically conducting post (16) is placed and towards the inner side of the cylinder the bore is sealed by a non-magnetic material (19) e.g. brass. The Hall-effect transducer (15) forms thus part of a closed magnetic circuit comprising the permanent magnet (17), the magnetically conducting post (16), the magnetically conducting disc (14) and the hydraulic cylinder wall surrounding the bore. When the piston in the hydraulic cylinder opposes the sensor, a second closed magnetically conducting circuit is formed comprising the permanent magnet, the magnetically conducting post, the piston, and the steel wall of the cylinder. In this way the magnetic field over the Hall-effect transducer is removed and the piston position can be registered by suitable electric detector circuits connected to the Hall-effect transducer.

대표청구항 ▼

A hydraulic cylinder with a piston slidable in the cylinder and with magnetic position indication comprising at least one magnetically sensitive component mounted in the cylinder wall, characterized in that the magnetically sensitive component is embedded in a magnetically essentially non-conducting

A hydraulic cylinder with a piston slidable in the cylinder and with magnetic position indication comprising at least one magnetically sensitive component mounted in the cylinder wall, characterized in that the magnetically sensitive component is embedded in a magnetically essentially non-conducting material and forms part of a first closed magnetic circuit comprising at least one permanent magnet, and that in a predetermined position to be indicated, the piston forms a second closed magnetically better conducting circuit including the permanent magnet, but excluding the magnetically sensitive component.