JPS6454717A - Differential transformer - Google Patents

Abstract

PURPOSE:To compensate a temperature by simple structure by movably installing a core into a coil, inserting and fixing the root section of a shaft into the central hole of the core and giving specific relationship between the core and the shaft. CONSTITUTION:A differentinal transformer is composed of coils 1, 2, a core 4 movable in the coils 1, 2 and a shaft 5 connected to the core 4. The root section side of the shaft 5 is inserted into the central hole 4a of the core 4, and the shaft 5 is fastened onto the inner circumferential surface of the central hole 4a in the swelling section of the root section 5a and connected to the core 4. Relationship shown in formula is given between these core 4 and shaft. In formula, L represents the distance between the nose of the shaft 5 and the center of the fixing section of the shaft 5, (l) is the distance between the center of the fixing section of the shaft 5 and the center of the core 4, alpha is the linear expansion coefficient of the core 4, and beta is the linear expansion coefficient of the shaft 5. Accordingly, even when there is a temperature change in the transformer, the distance between the nose of the shaft and the center of the core is not changed, thus allowing accurate measurement at all times without being affected by the temperature change.