Abstract: A water pump includes an impeller provided at a first end of a rotational shaft supported by a body via a bearing, a mechanical seal provided between the impeller and the bearing, a draining hole introducing a water drop leaked from an impeller side via the mechanical seal to a reservoir provided at a bottom of the body and having a side opening, a plugging member provided at the side opening of the reservoir for liquid-tightly sealing the reservoir, and an opening portion provided at the plugging member for communicating the reservoir and an atmosphere side.

Abstract: A water pump includes an impeller provided at a first end of a rotational shaft supported by a body via a bearing, a mechanical seal provided between the impeller and the bearing, a draining hole introducing a water drop leaked from an impeller side via the mechanical seal to a reservoir provided at a bottom of the body and having a side opening, a plugging member provided at the side opening of the reservoir for liquid-tightly sealing the reservoir, and an opening portion provided at the plugging member for communicating the reservoir and an atmosphere side.

Abstract: A cooling device of an engine includes a first liquid pump driven by decelerated rotation of an engine and for circulating the cooling liquid in the engine. A second liquid pump is driven by electricity and circulates the cooling liquid in the engine as a supplement to the first liquid pump.

Abstract: A cooling device for an internal combustion engine includes a brushless DC motor having a housing, an output shaft, a magnet rotor fixedly mounted on the output shaft, and a stator positioned in the housing and having three phase windings which are arranged in the circumferential direction around the magnet rotor, an impeller connected at an outside of the housing to one end of the output shaft of the motor and circulating a cooling liquid through the engine, and a radiator while the output shaft is being rotated. A device can be provided for generating heat at the phase windings for warming-up the cooling liquid if a temperature thereof is below a set value. A device can be provided for stopping the rotation of the output shaft of the motor without interrupting the energization of the motor when a temperature of the cooling liquid is below a set value.

Abstract: A numerical controller includes a control section for controlling operation of a machine, an application section which is separated from the control section and adapted to input data into the control section and to monitor a control status, and a communication network for connecting the control section and the application section. This structure makes it possible to reduce the overall size of the numerical controller. A program for a new function or an abnormality diagnosis program is also transmitted from the application section to the control section when required.

Abstract: An apparatus for detecting a residual grinding amount includes first and second feelers adapted to contact the peripheral surface of a workpiece such that they move, in accordance with a variation in the diameter of the workpiece, in opposite directions each perpendicular to the direction of deflection of the workpiece, and a first displacement detector for detecting relative displacement between the first and second feelers. The apparatus also includes a third feeler adapted to contact the peripheral surface of the workpiece such that it moves, in accordance with the variation in the diameter of the workpiece as well as a variation in the deflection of the workpiece, in the direction of deflection of the workpiece, and a second displacement detector for detecting displacement of the third feeler. The residual grinding amount is calculated based on the displacements detected by the first and second displacement detectors.

Abstract: In a method and apparatus for grinding a workpiece, a rotating workpiece and a rotating grinding wheel are relatively moved toward and away from each other, and at least first and second grinding steps are performed at high and low infeed rates, respectively. Further, back-off grinding is performed between the first and second grinding steps. A target workpiece diameter to be obtained at the end of the back-off grinding is first provided. During the rough grinding, prediction is repeatedly performed to obtain a workpiece diameter which would be obtained at the end of the back-off grinding if the back-off grinding were started instantaneously. The workpiece diameter is predicted taking account of a delay in the movement of the grinding wheel. The back-off grinding is started when it is judged that the predicted workpiece diameter becomes equal to the target workpiece diameter.

Abstract: A numerical controlled grinding machine for grinding a workpiece, in which a thermal displacement taking place between a wheel head and the workpiece, is detected with the workpiece not being subjected to the bending due to a grinding resistance. The thermal displacement is calculated from the difference between the present position of the wheel head detected by a position detector and the theoretical position thereof converted from the diameter of the workpiece measured by an in-process measuring device. The position data for the wheel head stored in a numerical controller is compensated for the calculated thermal displacement for use in the subsequent control of feed movement between the workpiece and the wheel head.

Abstract: In a grinding method wherein a rotating workpiece and a rotating grinding wheel are relatively moved toward and away from each other and wherein at least three of rough, fine and finish grinding step are performed successively at high, medium and low infeed rates respectively for grinding the workpiece, the grinding wheel is retracted to a back-off position at the end of the rough grinding step.

Abstract: An apparatus for displaying an operation sequence of a machine tool such as a grinding machine which is controlled by a numerical controller. During operation, successive operations instructed by a machine operator are stored in the memory of the numerical controller along with successive numerical commands which are executed during the successive operations. When a malfunction occurs in the machine tool, the storing operation is stopped, and the successive operations and the successive numerical commands executed before the occurrence of the malfunction are displayed on a display device for analyzing the cause of the malfunction.

Abstract: A numerically controlled machine tool for machining a non-circular workpiece according to profile data. The numerical controller of the machine tool memorizes the ideal profile data calculated from the ideal final shape of the workpiece, and the execution profile data calculated from the ideal profile data and compensated for position error due to the follow delay of the machine tool. The machine tool is controlled according to the execution profile data during grinding the workpiece with cut-in feed and spark-out grinding. The numerical controller has the capability of measuring position change of the main spindle and the tool slide during spark-out grinding. Then, the numerical controller ascertains whether or not the follow delays of the main spindle and the tool slide are within a prescribed tolerance depending on the measured position change and the ideal profile data.