Abstract: A railcar bogie includes: a cross beam to support a carbody of a railcar; wheels at both railcar width direction sides of the bogie lined up longitudinally at each side; a pair of front and rear axles respectively at a front side and rear side in the railcar longitudinal direction to sandwich the cross beam each of the axles connect wheels located at the left side and right side of the railcar; bearings at both railcar width direction sides of each axle to rotatably support the axle; axle box portions coupled to the cross beam via elastic members to store the bearing; and plate spring portions to respectively support both railcar width direction end portions of the cross beam and both railcar longitudinal direction end portions of the plate spring portions, supported by the axle box portions. The axle box portions include a surface that supports the plate spring portion.

Abstract: A control unit (14) makes an end effector (10) compliant with respect to an x-axis and a y-axis which are perpendicular to a z-axis parallel to a direction in which a shaft (20) is moved for insertion and makes the end effector (10) produce a pressing force acting in a direction parallel to the z-axis to press the shaft (20) against an internally toothed disk (22). The control unit (14) moves the compliance center of the shaft (20) along a predetermined groping route in a state where the pressing force acting in the direction parallel to the z-axis is produced by the end effector (10). The shaft (20) gripped by the end effector (10) repeats radially outward movement from a position near the center of the center opening (22b) of the internally toothed disk (22) in different phases in an xy plane defined by the x-axis and the y-axis to find a position where the splines (20a) of the shaft (20) are able to engage the internal teeth (22a) of the outermost internally toothed disk (22).