A drive shaft for a machine tool is connectable to a drilling tool. The drive shaft contains a cavity extending substantially over the entire length of the drive shaft and along the axis of rotation where the cavity contains an inflow opening through which water can be fed along the drive shaft into the drilling tool. An insert device is provided in the cavity, through which, to cool the drive shaft, the water is guided first in a first direction and then in a second direction where the insert device contains a first curved guide element and a second curved guide element for separating the water which is guided in the first direction from the water which is guided in the second direction. The cross-sectional area of the first curved guide element is designed point-symmetrically about a center longitudinal axis to the cross-sectional area of the second curved guide element.

A machine tool for cutting a workpiece with a cutting tool, includes a spindle motor that generates heat, a spindle head for supporting the spindle motor, and a heat insulating sheet disposed between the spindle motor and the spindle head. The area of a part of the heat insulating sheet that is in contact with a part of the spindle head having a high heat capacity is small so as to increase the amount of heat transferring from the spindle motor to the part of the spindle head having a high heat capacity, and thereby make the temperature distribution of the spindle head uniform.

The present invention particularly relates to a hand-held sanding machine with an outer housing (1), a tool shaft (2) and a brushless electric drive motor. In the present invention, the rotor of the drive motor is fastened to the tool shaft (2) of the sanding machine, and the stator (6) is positioned in the outer housing (1). The present invention also relates to a control method for an electric sanding machine.

A hand-held power tool, in particular a hammer drill or combi-hammer, including a tool housing having an accommodating region designed for accommodating a rechargeable tool battery, wherein, in the accommodating region, a contact region for electrically contacting the rechargeable tool battery as well as a connection region that is electrically connected to the contact region is provided, wherein the connection region is designed to convey a supply current provided by the rechargeable tool battery to an electric drive motor of the hand-held power tool, wherein the hand-held power tool has a cooling fan arranged in the tool housing and operated by the electric drive motor, by which cooling air for cooling the accommodating region can be sucked through the accommodating region, wherein at least one partitioning element is provided in the accommodating region in such a way that the contact region remains substantially free from cooling air sucked through the accommodating region.

The invention relates, on the one hand, to a machine element (6), for example a motor spindle or an electromechanical drive unit, with integrated, internal cooling system (8) and, on the other hand, to a closed cooling circuit (24) with corresponding machine element (6). According to the invention, the cooling takes place with a special coolant (4). The coolant (4) is a dispersion containing at least one Phase Change Material (PCM).

An angle grinder includes a housing formed with a handle, a clamping device for mounting a grinding disk, an output shaft for driving the clamping device to rotate, a brushless motor being provided with a motor shaft, a transmission mechanism for transmitting power between the motor shaft and the output shaft, and a circuit board assembly for providing electricity to the brushless motor. The clamping device is disposed outside of the housing and connected with the output shaft. The output shaft is at least partially disposed inside of the housing and connected with the transmission mechanism. The brushless motor is arranged between the transmission mechanism and the circuit board assembly in a direction substantially parallel to the motor shaft, and the motor shaft is disposed along a direction substantially perpendicular to the output shaft.

A motor driving device comprises a first heat sink arranged outside a housing, a second heat sink arranged inside the housing, and a heat conduction plate configured to thermally connect the first heat sink and the second heat sink. A switching element for a spindle is mounted on the first heat sink, and a switching element for a feed axis is mounted on the second heat sink.

A cooling medium accumulation part is integrally formed with a spindle housing and an attaching section between the spindle housing and the attaching section so that at least a width of the cooling medium accumulation part in a direction perpendicular to the spindle is wider than a width of the motor accommodation section in a virtual projection plane obtained by projecting the cooling medium accumulation part in a direction from the spindle housing to the attaching section. A straight oil supply through-holes communicating the cooling medium accumulation part and the cooling passages are formed in a side wall part of the spindle housing.

An object is to provide a machine-tool spindle cooling method and a machine tool capable of suppressing thermal deformation of a spindle while achieving energy saving. To achieve it, a machine-tool spindle cooling method is provided in which bearings (13) and a spindle rotation motor (14) that generate heat with rotation of a spindle (12) are cooled by causing a spindle cooling device (18) to supply and circulate cooled cooling oil inside a housing (11) rotatably supporting the spindle (12), the method comprising deactuating the spindle cooling device (18) to thereby stop supplying the cooling oil in a case where the number of revolutions of the spindle (12) is less than or equal to a predetermined number of revolutions and the temperatures of the bearings (13) and the spindle rotation motor (14) detected by temperature sensors (15, 16) are less than or equal to a predetermined temperature.

A cooling gas is fed from an ejection nozzle into the interior of a through-hole which is formed in a radially central portion of a main spindle, and which penetrates through said main spindle in an axial direction. The cooling gas passes through radial venting holes provided in a plurality of locations, in the circumferential direction, in an axially intermediate portion of the main spindle, is fed into axial venting holes provided in a plurality of locations, in the circumferential direction, extending from one axial-direction end of the main spindle to an intermediate portion thereof, is caused to flow through the axial venting holes, and is discharged from discharge holes.