Abstract: In a heating unit, based on a required output amount Q, a control part 50 performs: (A) when the required output amount Q is not more than a predetermined set value, a control in which none of the heating devices 24a is continuously kept on throughout a heating cycle, and all or one or more heating devices 24a are controlled in a periodically divided manner; and (B) when the required output amount is larger than the predetermined set value, a control in which all or one or more heating devices 24a are continuously kept on throughout the heating cycle, and all or one or more heating devices 24a among the remaining heating devices 24a are controlled in the periodically divided manner during this heating cycle. At this time, a difference between the maximum number and the minimum number of the heating devices 24a that are simultaneously kept on during the heating cycle is made not more than 1.

Abstract: To provide a compact size machine tool free from the inconveniences inherent to the prior art and excellent in the collection and removal of chips or the like, there is provided a channel 39 in a central portion of the bed 3 directly beneath the table 21 and extending parallel to the table moving direction; a chip conveyor 47 being provided inside the channel 39; on both sides with respect to the channel 39, a pair of opposite slopes 51, 51 for collection of chips as well as telescopic covers 53, 53 extensible or contractible in accordance with the displacement of the table 21 being provided so as to cover a pair of guide rails 13, 13 which extend parallel to each other along the Z direction.

Abstract: A rolling-contact type bearing for rotatably supporting a spindle of a machine is cooled by a temperature controlled liquid lubricant supplied to an internal cavity or passageways provided in the spindle, and circulated toward the bearing so that the temperature controlled liquid lubricant comes into direct or indirect contact with the bearing in the order of the inner race, the rolling element, and the outer recess, to thereby apply a cooling and lubricating effect to those elements. The lubricant after cooling is collected to a lubricant-temperature controller to be subjected to a temperature control treatment for reuse as a coolant. An air seal is applied to a lubricant entrance of the spindle where the temperature controlled lubricant is supplied from a lubricant supply member into the spindle, to thereby prevent a leakage of the lubricant toward the exterior.