US 12,186,821 B2
Electric discharge machine and sensor unit
Masashi Sakaguchi, Kanagawa (JP)
Assigned to Sodick Co., Ltd., Kanagawa (JP)
Filed by Sodick Co., Ltd., Kanagawa (JP)
Filed on Jun. 20, 2021, as Appl. No. 17/352,351.
Claims priority of application No. 2020-116424 (JP), filed on Jul. 6, 2020.
Prior Publication US 2022/0001474 A1, Jan. 6, 2022
Int. Cl. B23H 7/32 (2006.01); G01B 5/00 (2006.01); G01D 5/20 (2006.01); G01D 5/34 (2006.01)
CPC B23H 7/32 (2013.01) [G01B 5/0014 (2013.01); G01D 5/20 (2013.01); G01D 5/34 (2013.01); B23H 2500/20 (2013.01)] 5 Claims
OG exemplary drawing
 
1. An electric discharge machine, comprising:
an axis drive part, configured to move a tool electrode in at least one axial direction; and
a sensor unit, configured to detect a linear movement position of the axis drive part in the at least one axial direction,
wherein the sensor unit comprises:
a measurement scale, having a linear shape;
a position detector, configured to scan the measurement scale and obtain position information; and
a pair of adjustment blocks, being fixed to both ends of the measurement scale or the position detector and erected perpendicular to an extension direction of the measurement scale,
wherein each of the pair of adjustment blocks comprises a first block and a second block made of different materials, being joined with each other through a fastening surface, and
wherein each of the pair of adjustment blocks is fixed to the axis drive part and is curved in the at least one axial direction due to a temperature change,
wherein an internal stress is generated in the fastening surface due to a difference in coefficient of thermal expansion between the first block and the second block, and the adjustment block is curved due to a bimetal effect.