Handheld electric machine tool

Abstract

A handheld electric machine tool is described including a housing with a grip area, a tool area for a tool that is drivable in a linear and/or oscillating manner, an operating part on the housing for activation of the tool and/or the electric machine tool by the user, a drive unit disposed in the housing for producing a working motion of the tool, an electronic unit disposed in the housing for acting upon the drive unit with at least control and/or regulating signals, an operating voltage unit for supplying an electrical DC voltage, the drive unit including at least one excitation actuator having a volume of excitation-active material, which excitation actuator when in operation is electrically supplied by the operating voltage unit, is controlled or regulated by the electronic unit. The electronic unit may be configured to operate the at least one excitation actuator in a resonant frequency.

1 - 28 . (canceled) 
     
     
         29 . A handheld electric machine tool, comprising:
 a housing with a grip area;   a tool area for a tool that is drivable in at least one of a linear and oscillating manner;   an operating part on the housing for activation by a user of at least one of the tool and the electric machine tool;   a drive unit disposed in the housing to produce a working motion of the tool;   an electronic unit disposed in the housing to act upon the drive unit with at least one of control signals and regulating signals; and   an operating voltage unit to supply an electrical DC voltage, wherein the drive unit includes at least one excitation actuator having a volume of excitation-active material, which excitation actuator when in operation is electrically supplied by the operating voltage unit, is controlled or regulated by the electronic unit;   wherein the electronic unit is configured to operate the at least one excitation actuator in a resonant frequency.   
     
     
         30 . The handheld electric machine tool as recited in  claim 29 , wherein the electronic unit includes a regulating unit with frequency matching for re adjustment of the resonant frequency of the at least one excitation actuator. 
     
     
         31 . The handheld electric machine tool as recited in  claim 29 , wherein the excitation-active material is piezoelectric. 
     
     
         32 . The handheld electric machine tool as recited in  claim 31 , wherein a volume of the piezoelectric material is at least 0.2 cm 3 . 
     
     
         33 . The handheld electric machine tool as recited in  claim 31  wherein a volume of the piezoelectric material is at least 0.5 cm 3 . 
     
     
         34 . The handheld electric machine tool as recited in  claim 31  wherein a volume of the piezoelectric material is at least 1 cm 3 . 
     
     
         35 . The handheld electric machine tool as recited in  claim 32 , wherein the at least one excitation actuator has a power density of at least 5 Watt/cm 3 , based on the volume of the piezoelectrically active material of the at least one excitation actuator. 
     
     
         36 . The handheld electric machine tool as recited in  claim 35  wherein the power density is at least 20 Watt/cm 3 . 
     
     
         37 . The handheld electric machine tool as recited in  claim 29 , wherein the at least one excitation actuator has, at a tip of the tool, an oscillation amplitude of at least 3 μm. 
     
     
         38 . The handheld electric machine tool as recited in  claim 37 , wherein the oscillation amplitude is at least 8 μm. 
     
     
         39 . The handheld electric machine tool as recited in  claim 37 , wherein the oscillation amplitude is at least 12 μm. 
     
     
         40 . The handheld electric machine tool as recited in  claim 29 , wherein on an input side of the electronic unit, an electrical power for acting upon the at least one excitation actuator is at least 20 Watt. 
     
     
         41 . The handheld electric machine tool as recited in  claim 29 , wherein a disc thickness of the excitation actuator is from 1 mm to 10 mm. 
     
     
         42 . The handheld electric machine tool as recited in  claim 41 , wherein the disc thickness is between 2 mm to 6 mm. 
     
     
         43 . The handheld electric machine tool as recited in  claim 41 , wherein the disc thickness is 5 mm. 
     
     
         44 . The handheld electric machine tool as recited in  claim 31 , wherein an input field strength of the at least one excitation actuator is in the range below 300 V/mm, based on a thickness of the piezoelectrically active material. 
     
     
         45 . The handheld electric machine tool as recited in  claim 44 , wherein the range is from 50 V/mm to 220 V/mm. 
     
     
         46 . The handheld electric machine tool as recited in  claim 29 , wherein an input voltage of the at least one excitation actuator is in a range below 1000 Volts. 
     
     
         47 . The handheld electric machine tool as recited in  claim 46 , wherein the range is from 300 Volts to 700 Volts. 
     
     
         48 . The handheld electric machine tool as recited in  claim 29 , wherein an electrical output voltage of the operating voltage unit is below 100 Volts. 
     
     
         49 . The handheld electric machine tool as recited in  claim 29 , wherein an electrical output voltage of the operating voltage unit is above 100 Volts. 
     
     
         50 . The handheld electric machine tool as recited in  claim 29 , wherein an operating frequency of the at least one excitation actuator is in the range of from 10 kHz to 1000 kHz. 
     
     
         51 . The handheld electric machine tool as recited in  claim 50 , wherein the range is from 30 kHz to 50 kHz. 
     
     
         52 . The handheld electric machine tool as recited in  claim 50 , wherein the range is from 35 kHz to 45 kHz. 
     
     
         53 . The handheld electric machine tool as recited in  claim 29 , wherein the operating voltage unit includes an electrochemical storage device. 
     
     
         54 . The handheld electric machine tool as recited in  claim 53 , wherein the electrochemical storage device is rechargeable. 
     
     
         55 . The handheld electric machine tool as recited in  claim 29 , wherein the operating voltage unit includes a rectifier. 
     
     
         56 . The handheld electric machine tool as recited in  claim 29 , wherein the electronic unit is concentrated on a printed circuit board. 
     
     
         57 . The handheld electric machine tool as recited in  claim 29 , wherein the electronic unit includes at least one inductance provided in a power circuit acting upon the at least one excitation actuator with electrical power for at least one of signal filtering and inductive compensation of the at least one excitation actuator. 
     
     
         58 . The handheld electric machine tool as recited in  claim 29 , wherein at least the drive unit, the electronic unit and the operating voltage unit are distributed in the housing in such a manner that a center of gravity lies in a region of the grip part. 
     
     
         59 . The handheld electric machine tool as recited in  claim 29 , wherein the drive unit further includes at least one further drive component. 
     
     
         60 . The handheld electric machine tool as recited in  claim 29 , wherein the at least one excitation actuator forms a main energy consumer of the electric machine tool, for which at least 50% of the electrical input power is provided. 
     
     
         61 . The handheld electric machine tool as recited in  claim 29 , further comprising:
 at least one of an optical, acoustic, and haptic operating indicator to indicate an activated state of the at least one excitation actuator.   
     
     
         62 . The handheld electric machine tool as recited in  claim 29 , further comprising:
 an illumination element for a working area.   
     
     
         63 . The handheld electric machine tool as recited in  claim 29 , wherein the excitation actuator is configured to generate superimposed oscillations in the tool which are superimposed on a working motion of the tool. 
     
     
         64 . The handheld electric machine tool as recited in  claim 29 , wherein the tool is rotatably supported and a working motion of the tool is a rotational motion. 
     
     
         65 . The handheld electric machine tool as recited in  claim 64 , wherein the tool is a grinding wheel. 
     
     
         66 . The handheld electric machine tool as recited in  claim 63 , wherein the superimposed oscillations excite the tool in at least one of (i) orthogonally to a plane of motion of the tool in which the working motion of the tool takes place, (ii) in a direction of the longitudinal axis of a tool shaft carrying the tool, (iii) in a plane of motion in which the working motion of the tool takes place, and (iv) perpendicularly to the tool shaft. 
     
     
         67 . The handheld electric machine tool as recited in  claim 29 , wherein the excitation actuator acts upon a bearing of the tool. 
     
     
         68 . The handheld electric machine tool as recited in  claim 29 , wherein an excitation-active material of the excitation actuator is magneto-restrictive.