Abstract: In a thermal displacement compensating device and a thermal displacement compensating method for a machine tool, a block temperature obtaining section obtains temperatures of respective blocks based on temperature information detected by temperature sensors wherein temperatures in each of the respective blocks into which a column is divided to be pluralized are defined as a uniform value. An FEM analysis section performs a structural analysis by a finite element method based on the temperatures of the respective blocks obtained by the block temperature obtaining section and infers thermal displacement amounts of the column. A compensation value calculation section calculates a compensation value for a machining command position based on the thermal displacement amounts of the column inferred by the FEM analysis section. A compensation section compensates the machining command position by the compensation value obtained by the compensation value calculation section.

Abstract: There are provided a power transmission chain which can reduce a noise level further by eliminating unfavorable combinations from a random arrangement of combinations of pitch lengths and pin shapes and a power transmission system using the same power transmission chain. With respect to pitch length, links include two types of a link L1 which has a small pitch length and a link L2 which has a large pitch length. With respect to pin shape, pins include two types a pin P1 of which a curvature of a rolling contact surface is large and a pin P2 of which the curvature of the rolling contact surface is small. The links are arranged so that a possibility is avoided that a combination of (L2, P2) and a combination of (L2, P1) come immediately after a combination of (L1, P2) in a chain traveling direction, and that a possibility is adopted that a combination of (L1, P2) or a combination of (L1, P1) comes immediately after the combination of (L1, P2).

Abstract: In a bearing device, a double row rolling bearing for supporting a pinion gear-side portion of a pinion shaft on a case (annular wall) is formed by a tandem-type double row angular contact ball bearing. A first row of balls having a larger pitch circle diameter are disposed between inner and outer rings of the double row angular contact ball bearing at a region near to the pinion gear, and a second row of balls having a smaller pitch circle diameter are disposed between the inner and outer rings at a region remote from the pinion gear. A bearing internal space is divided into a first bearing internal space containing the first ball row and open toward the pinion gear and a second bearing internal space containing the second ball row and sealed by partition walls formed respectively by bearing seals, lubricating grease being sealed in the second bearing internal space.