Hand-held machine tool comprising a drive motor

Patent metadata

Field	Value
Publication number	US-11040439-B2
Application number	US-201716086516-A
Country	US
Kind code	B2
Filing date	Apr 10, 2017
Priority date	Apr 11, 2016
Publication date	Jun 22, 2021
Grant date	Jun 22, 2021

Abstract

A hand-held machine tool, in particular a sanding machine, including a rod-type handle element for the user to grip and a processing head which is moveably mounted on the handle element by means of a joint assembly. The processing head has an electric drive motor for driving a tool holder provided for holding a processing tool and a speed-reducing gearbox between the drive motor and the tool holder, the gearbox being designed to achieve a reduction in speed of an output of the drive motor relative to a speed of the tool holder. The drive motor is a brushless motor and a power supply system for the drive motor is arranged at a distance from the drive motor on the handle element, the power supply system being connected to the drive motor by means of a cable arrangement.

First claim

The invention claimed is:

1. A hand-held machine tool comprising a rod-shaped handle element for a user to grip and a machining head, which is movably mounted on the handle element by means of a joint assembly, said machining head having an electric drive motor for driving a tool holder provided for holding a machining tool, and a speed-reducing gear unit between the drive motor and the tool holder, said gear unit being designed to achieve a reduction in speed of an output of the drive motor relative to a speed of the tool holder, wherein the drive motor is a brushless motor and a power supply system for the drive motor is arranged at a distance from the drive motor on the handle element, the power supply system being connected to the drive motor by means of a line arrangement,
wherein the drive motor has a stator with an exciter coil arrangement and a rotor with a motor shaft, having a drive for driving the tool holder, wherein a fan propeller is connected in a torsionally-rigid manner or rotatably coupled to the motor shaft, wherein the motor shaft, on its longitudinal end regions, is rotatably supported by a drive bearing arranged in the area of the output and a motor bearing arranged at the other longitudinal end region, so that it can rotate with respect to the stator, wherein the exciter coil arrangement is arranged between the fan propeller and the output of the motor shaft and the fan propeller is designed to generate a cooling air flow for the drive motor flowing from the fan propeller to the output.

2. The hand-held machine tool according to claim 1 , wherein the power supply system is arranged on or directly alongside a handle region for gripping the handle element by an operator and/or wherein the power supply system is arranged in a housing.

3. The hand-held machine tool according to claim 1 , wherein the gear unit comprises a gear unit or an eccentric gear unit generating a hypercycloid motion of the tool holder.

4. The hand-held machine tool according to claim 1 , wherein the line arrangement for each phase of an exciter coil arrangement of the drive motor comprises in each case a conductor or exclusively one conductor.

5. The hand-held machine tool according to claim 1 , wherein the conductor of the line arrangement for supplying the phases of the drive motor individually or as a whole are arranged in at least one electromagnetically-screening screening device.

6. The hand-held machine tool according to claim 1 , wherein the line arrangement comprises conductors provided exclusively for supplying power to the drive motor and/or between the drive motor and the power supply system, no data line exclusively for data transmission and not for supplying power to the drive motor runs to a sensor arranged on the drive motor.

7. The hand-held machine tool according to claim 1 , wherein the distance between the machining head and the power supply system is at least two or three times a diameter of the machining head and/or a length of the power supply system or its housing and/or wherein it has at least one energy storage device connection for an electrical energy storage device, and/or a connection device for connection to an electrical energy supply network.

8. The hand-held machine tool according to claim 1 , wherein an axis of rotation of the output of the drive motor and an axis of rotation of the tool holder are parallel to one another or are at an angle of a maximum of 30° to one another and/or wherein the drive motor does not protrude beyond a machining surface of the machining tool and/or beyond a cover of the machining head for the machining tool transversally to the axis of rotation of the tool holder.

9. The hand-held machine tool according to claim 1 , wherein the drive motor is arranged outside a centre of gravity or centre of the machining head and/or alongside a pivot axis of the joint assembly on the machining head.

10. The hand-held machine tool according to claim 1 , wherein the drive motor is arranged in a motor housing, on which at least one protection body is provided for damping a mechanical shock impacting on the motor housing and/or at least one hoop guard can be arranged to protect the motor housing from mechanical loading.

11. The hand-held machine tool according to claim 10 , wherein the protection body is arranged on an area of the motor housing facing away from the machining head and/or has a circular design and/or comprises an elastic material, and/or is a plug-in component detachable from the motor housing, which can be plugged into a socket opening of the motor housing.

12. The hand-held machine tool according to claim 1 , wherein the handle element comprises a grip rod or is rod-shaped.

13. The hand-held machine tool according to claim 1 , wherein the power supply system and the machining head are arranged on opposing end regions of the handle element.

14. The hand-held machine tool according to claim 1 , wherein a line arrangement connecting the drive motor with the power supply system is run and/or arranged along the handle element.

15. The hand-held machine tool according to claim 14 , wherein the line arrangement comprises conductors exclusively provided for supplying power to the drive motor.

16. The hand-held machine tool according to claim 1 , wherein, between the power supply system and the drive motor, no data line is provided or runs that serves exclusively for data transmission and not for supplying power to the drive motor.

17. A hand-held machine tool comprising a rod-shaped handle element for a user to grip and a machining head, which is movably mounted on the handle element by means of a joint assembly, said machining head having an electric drive motor for driving a tool holder provided for holding a machining tool, and a speed-reducing gear unit between the drive motor and the tool holder, said gear unit being designed to achieve a reduction in speed of an output of the drive motor relative to a speed of the tool holder, wherein the drive motor is a brushless motor and a power supply system for the drive motor is arranged at a distance from the drive motor on the handle element, the power supply system being connected to the drive motor by means of a line arrangement,
wherein the power supply system for supplying power to the drive motor is connected with the drive motor via a line arrangement and, on the drive motor, a protective circuit is arranged with at least one electrical disconnector for isolating a connection between at least one electrical conductor of the line arrangement and a phase that can be supplied with current via this conductor of an exciter coil arrangement of the drive motor.

18. The hand-held machine tool according to claim 17 , wherein the power supply system and the drive motor in each case have at least one fan, and/or, on a motor shaft of the drive motor, a fan propeller is arranged in a torsionally-rigid manner.

19. The hand-held machine tool according to claim 17 , wherein the drive motor is arranged in an electromagnetically screening housing formed by the motor housing or arranged in the motor housing and/or an air routing body arranged in the motor housing for guiding cooling air through the drive motor or past the drive motor and/or connected with a screening electromagnetically screening one of the conductors.

20. The hand-held machine tool according to claim 17 , wherein the at least one disconnector comprises or forms a thermally operable switch, which isolates the conductor from the phase associated with it, as a function of a predetermined temper

Assignees

• Festool Gmbh

Inventors

• Walker Nico

Classifications

• B25F5/00 Primary

  Details or components of portable power-driven tools not particularly related to the operations performed and not otherwise provided for · CPC title

• B25F5/001 Primary

  Gearings, speed selectors, clutches or the like specially adapted for rotary tools · CPC title

• B24B7/186

  with disc-type tools · CPC title

• B24B7/184 Primary

  pole sanders · CPC title

• B25F5/008

  Cooling means · CPC title