Dr. Johannes Heidenhain Gmbh

Johannes Heidenhain Gmbh

Hiroshi Haga

Mamoru Yamashita

Takeshi Yamamoto

Andre Schramm

A rotary encoder includes a rotary shaft that may be manufactured easily and efficiently includes a rotating magnet with a mounting precision in which variance may not occur readily. A rotary shaft includes a rotary shaft main unit with a rotating magnet mounting part for mounting a rotating magnet and a ring-shaped rotating magnet that is formed integrally with this rotating magnet mounting part of the rotary shaft. In a method of manufacturing the rotary shaft, a ring-shaped rotating magnet is formed integrally with the rotary shaft mounting part of the rotary shaft main unit.

Rotary encoder

In a position measuring device in which data, which requires buffering, may be held without accommodating a high-capacitance capacitor in the inside of the encoder, a backup current source may be exchanged while the circuits required for the operating capability state remain operable. In addition, current usage during the buffering time may be held low, and the service life of the backup current source may be extended, so that the demand for maintenance may be reduced. The position measuring device may include an encoder main part, arranged to measure the extent of the shift in position of an object to be measured, and a backup current source arranged to supply backup current when main current source, that supplies encoder main part with current, is interrupted. Outside of the encoder main part, an auxiliary current source is provided which, during the exchange of a main battery of the backup current source, undertakes supplying backup current in place of this main battery. The backup current source supplies backup current only to those circuits of the encoder main part which require buffering.

Position measuring device

To provide a low-cost magnetic detection circuit, in which the differential detection function accomplished by outputting differential signals may not be lost, and which may be hardly affected by temperature fluctuations and may be resistant to noise, and in which the number of magnetic detection elements may be reduced, and to provide an encoder, the costs of which may be further reduced by using such a magnetic detection circuit for the multi-revolution detection part, etc., a magnetic detection circuit includes a bridge circuit formed by two bridge sections between the current-source terminal and the grounding terminal. The first bridge section and the second bridge section of the bridge circuit include magnetic detection elements MR, MR, respectively, and, viewed from the output-signal output points, the magnetic detection elements MR, MRin the two bridge sections are arranged on only one of the sides that include the current-source side and the grounding-terminal side. An encoder includes such a magnetic detection circuit.

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Fuchu, Japan

Hiroshi Haga