| 摘要 |
PURPOSE:To decrease the effect on a machined diameter, by providing a step difference in a mounting surface of the headstock and bed in a horizontal bed lathe, equalizing the minimum distance of tightening point positions of each mounting surface from the center of a spindle and arranging the direction of the thermal displacement of the spindle to the direction at a right angle with the cutting direction of a tool. CONSTITUTION:The cutting direction of a tool 7 in a horizontal bed lathe is sloped to an equal direction for a horizontal level. A mounting surface of a headstock 3 to a bed 1 is formed by the first and second mounting surfaces 1a and 1b having a vertical step difference. The first lower mounting surface 1a is arranged below a spindle 2, and the second mounting surface 1b higher than the former is successively arranged to a cutting direction of the tool 7. A minimum distance of positions of tightening bolts 8a, 8b in each mounting surface 1a, 1b from the center of the spindle 2 is equalized, and the thermal displacement of the spindle center O, displaced to the front diagonal Y-Y direction on the bisector of an angle <AOB formed by tightening points A, B of the tightening bolts 8a, 8b and the spindle center O, is generated to the direction at a right angle with a cutting direction of the tool to decrease the effect to a machined diameter and obtain stable machining accuracy. |
