Apparatus for controlling temperature of machine tool

Claim 1

A temperature control apparatus for a machine tool which includes a constituent element having a heat generating source, a heat transfer fluid brought into contact with the constituent element cool it, and a heat exchanger for cooling the heat transfer fluid with a cooling medium to control temperature of said heat transfer fluid connected to a heat transfer fluid outlet of said constituent element to maintain a set temperature difference between a reference temperature and said temperature of said heat transfer fluid at said outlet, wherein the improvement comprises: a reference temperature sensor for detecting, said reference temperature; a heat exchanger outlet temperature sensor for detecting temperature of said heat transfer fluid at an outlet of said heat exchanger; a constituent element inlet temperature sensor for detecting temperature of said heat transfer fluid at an inlet of said constituent element; a constituent element outlet temperature sensor for detecting temperature of said heat transfer fluid at the heat transfer fluid outlet of said constituent element; differential temperature detecting means constituted by said reference temperature sensor, said heat exchanger outlet temperature sensor, said constituent element inlet temperature sensor and said constituent element outlet temperature sensor; and control means activated in accordance with a value of an output signal from said differential temperature detecting means to control the temperature of said heat transfer fluid; wherein a differential temperature between said heat exchanger outlet temperature and said constituent element input temperature operates in said output signal provided to said control means such that both transient deviations of heat transfer fluid temperature and steady-state deviations of machine tool body temperature are minimized.