Gearless hand tool

Abstract

Hand-held power tool with at least one tool spindle (12a; 12b), with a drive unit (14a; 14b) having a brushless electric motor (30a), with a rechargeable battery (18a; 18b), in particular a lithium-based rechargeable battery, which is provided for supplying the drive unit (14a; 14b) with electrical energy, and with a hand-held power tool housing (20a) having a housing element (46a, 48a) extending substantially parallel to a rotational axis (54a) of the tool spindle (12a) along the drive unit (14a) and the tool spindle (12a), wherein the drive unit (14a, 14b) is connected gearlessly to the tool spindle (12a; 12b) and is provided for rotating the tool spindle (12a; 12b) at a rotational speed greater than 10,000 min -1to drive, wherein the drive unit (14a; 14b) receives a direct voltage for supplying the electric motor (30a) in at least one operating state, wherein the drive unit (14a; 14b) has an electronic commutator (36a) which is provided to convert the direct voltage at least into an alternating voltage, wherein the drive unit (14a; 14b) is provided to brake a rotor (38a) of the electric motor (30a) via a motor driver (32a).

Description

State of the art

[0001] The invention is based on a hand-held power tool according to the preamble of claim 1.

[0002] There is already a hand-held power tool with at least one tool spindle and a drive unit which is intended to rotate the tool spindle at a speed greater than 10 000 min -1 to drive, has been proposed. Further subject matters can be found in DE 10 2006 032 920 A1, DE 10 2007 037 125 A1, DE 10 2008 041 682 A1, DE 697 26 871 T2, DE 35 45 705 A1, US 2011 / 0 031 922 A1 and US 2011 / 0 000 691 A1. Disclosure of the invention

[0003] The invention is based on a hand-held power tool with at least one tool spindle and a drive unit which is intended to rotate the tool spindle at a speed greater than 10,000 min -1 to drive.

[0004] It is proposed that the drive unit comprise a brushless electric motor. A “tool spindle” is to be understood in particular as a shaft which, during operation, transmits torque to a tool chuck of the handheld power tool. The tool spindle preferably transmits the torque directly to the tool chuck. Advantageously, the tool spindle is connected to the tool chuck in a rotationally fixed manner. Preferably, the tool spindle is fixedly connected to the tool chuck in the axial direction. In particular, a “drive unit” is to be understood as a unit which, during operation, rotates an insert tool fastened in the tool chuck. Advantageously, the drive unit converts electrical energy into rotational energy. “Provided” is to be understood in particular as specially programmed, designed and / or equipped.In particular, "rotational speed" should be understood as a parameter that indicates the rotational speed of the tool spindle around a rotational axis of the tool spindle. Advantageously, the drive unit drives the tool spindle at a speed greater than 15,000 rpm. -1 particularly advantageous greater than 20 000 min -1 A "brushless electric motor" is understood, in particular, to mean an electric motor designed to transfer drive energy, in an energy form different from electrical energy, from a stator of the electric motor to a rotor of the electric motor. Preferably, the electric motor transfers the drive energy from the stator to the rotor by means of a magnetic field. The inventive design of the handheld power tool allows for a small overall size, high efficiency, and low wear.

[0005] In one embodiment of the invention, it is proposed that the drive unit, in at least one operating state, receives a direct current to supply the electric motor, thereby enabling a structurally simple power supply, in particular with a rechargeable battery. A "direct current" is understood, in particular, to mean a voltage that has a constant polarity relative to a zero potential of the drive unit. Preferably, the direct current has a constant value, different from the zero potential, over a period of time in at least one operating state.

[0006] According to the invention, the drive unit has an electronic commutator which is provided for converting the direct voltage at least into an alternating voltage, thereby enabling particularly high efficiency and advantageously low wear. A motor driver of the drive unit preferably has the commutator. Particularly preferably, the commutator is arranged and / or fastened separately from the electric motor. Alternatively or additionally, the electric motor of the drive unit could have a commutator. In particular, “electronic” should be understood to mean that the commutator, during operation, converts the direct voltage into an alternating voltage in a manner different from mechanical switching. The commutator preferably influences at least one electric current in a gas, in a vacuum and / or advantageously in a semiconductor.The electronics preferably comprise at least one transistor, particularly preferably at least one microprocessor. An "alternating voltage" is understood, in particular, to mean a voltage that, in at least one operating state, has a value that fluctuates around a mean value, particularly periodically. The alternating voltage preferably fluctuates sinusoidally. The value preferably fluctuates around the zero potential. The commutator preferably converts the direct voltage into a plurality of alternating voltages, particularly phase-shifted ones.

[0007] It is further proposed that the commutator be designed to convert the DC voltage dependent on a rotational speed, in particular of the tool spindle and / or advantageously of the rotor, into an AC voltage, thereby achieving particularly high efficiency. In particular, the phrase "dependent on a rotational speed" should be understood to mean that a fluctuation in the AC voltage is dependent on the rotational speed. Preferably, a period of the AC voltage is linear to the rotational speed. Alternatively, an amplitude of the AC voltage could be dependent on the rotational speed.

[0008] It is also proposed that the electric motor have an internal rotor, which allows for a particularly compact design with a simple construction. An "internal rotor" is understood, in particular, to be a rotor arranged within a stator, which, during operation, is firmly connected to a hand tool housing of the hand-held power tool.

[0009] Furthermore, it is proposed that the drive unit be designed to brake a rotor of the electric motor, thereby achieving a high level of safety and advantageous handling. In particular, the handheld power tool can be quickly and safely put away by an operator after being switched off. In this context, "braking" should be understood in particular to mean that the drive unit counteracts any movement of the rotor relative to a handheld tool housing of the handheld power tool.

[0010] In an advantageous embodiment of the invention, it is proposed that the drive unit have a maximum power of between 15 watts and 150 watts, thereby enabling effective workpiece processing with a compact design. In particular, "maximum power" should be understood as the maximum power consumed by the drive unit for driving the tool spindle during operation.

[0011] Furthermore, it is proposed that the handheld power tool comprise a lithium-based battery intended to supply the drive unit with electrical energy, thereby achieving particularly small installation space and low weight with high performance. A "lithium-based battery" should be understood in particular as a battery that stores electrical energy during a charging process using a lithium-chemical process. Preferably, the battery has an operating voltage between 3 volts and 15 volts. Particularly preferably, the battery has an operating voltage between 3 volts and 7.6 volts. Advantageously, the battery has a storage capacity between 2 and 25 Wh, particularly advantageously between 4 and 10 Wh.

[0012] According to the invention, the drive unit is connected to the tool spindle without a gear, which enables particularly low unit costs and minimal wear. In particular, "connected without a gear" should be understood to mean that a rotor of the drive unit and the tool spindle rotate at the same speed during operation.

[0013] It is further proposed that the hand-held power tool have a hose coupling that connects the drive unit to the tool spindle, thereby allowing manufacturing tolerances to be compensated for in a simple design and protecting the electric motor. A “hose coupling” should be understood in particular to be a tubular, rubber-elastic means that is intended to transmit a force from the drive unit to the tool spindle. Preferably, the hose coupling is non-positively connected to the drive unit and / or the tool spindle. Advantageously, the hose coupling encloses the drive unit and / or the tool spindle on at least one plane by 360 degrees. Preferably, the hose coupling is intended to release a rotationally fixed connection between the drive unit and the tool spindle in the event of a blockage of an inserted tool, in particular by slipping a non-positive connection. drawing

[0014] Further advantages will become apparent from the following description of the drawings. The drawings illustrate two exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0015] They show: Fig. 1 a hand-held power tool according to the invention in a perspective view, Fig. 2 the hand tool Fig. 1 without a hand tool housing of the hand tool, Fig. 3 a block diagram of a part of the hand tool from Fig. 1, Fig. 4 a side view of the hand tool from Fig. 1, Fig. 5 a top view of the hand tool from Fig. 1, Fig. 6 a part of a lighting unit of the hand tool from Fig. 1, Fig. 7 an alternative embodiment of the hand tool from Fig. 1 and Fig. 8 a system with a hand tool charger and the hand tool from Fig. 7. Description of the embodiments

[0016] Fig. 1 and Fig. 2 shows a handheld power tool 10a according to the invention, comprising a tool spindle 12a, a drive unit 14a, a tool chuck 16a, a battery 18a, and a handheld tool housing 20a. The drive unit 14a rotates the tool spindle 12a during workpiece machining. The drive unit 14a is connected to the tool spindle 12a without a gear.

[0017] In an operating state, the drive unit 14a drives the tool spindle 12a at a speed greater than 10,000 min -1In this embodiment, the speed is adjustable by an operator between 10,000 rpm -1 and 40,000 rpm -1adjustable. The handheld power tool 10a has a hose coupling 22a which, in an operational state, connects a rotor of the drive unit 14a to the tool spindle 12a. The handheld power tool 10a has two bearings 24a which, in an operational state, mount the tool spindle 12a in the handheld tool housing 20a. If an insert tool 26a becomes blocked in the workpiece, a force-locking connection between the hose coupling 22a and the drive unit 14a or the tool spindle 12a slips. The handheld power tool 10a has a spindle lock (not shown in detail) which, in at least one operating state, fastens the tool spindle in a rotationally fixed manner relative to the handheld tool housing 20a. The spindle lock has a push button which engages in a recess (not shown in detail) in the tool spindle 12a.By blocking the tool spindle 12a, the operator can open the tool chuck 16a for a tool change by a rotary movement.

[0018] In an operational state, the tool chuck 16a secures the insert tool 26a. The insert tool 26a is embodied here as an engraving knife. Alternatively, the tool chuck 16a could secure a milling cutter, a grinding wheel, a grindstone, a polishing tip, a polishing wheel, a polishing brush, a cutting wheel, a saw blade with a diameter of less than 50 mm, and / or a drill bit with a diameter of less than 5 mm for workpiece machining.

[0019] The battery 18a is based on lithium-chemical energy storage. The battery 18a has a storage capacity of 6 Wh. It provides a voltage of 7.2 volts when ready for operation. During operation, the battery 18a supplies the drive unit 14a with electrical energy. The battery 18a has two battery cells 28a. The battery cells 28a are connected in series.

[0020] The drive unit 14a is designed as an electrically commutated drive unit 14a. The drive unit 14a has a brushless electric motor 30a and a motor driver 32a. The rotor of the electric motor 30a is formed internally. The motor driver 32a supplies the electric motor 30a with energy by means of an alternating voltage during operation. The motor driver 32a has a Fig. 3. The commutator 36a has at least one transistor (not shown in detail). During operation, the commutator 36a converts a direct voltage into an alternating voltage for energy transmission to a Fig. 3 of the electric motor 30a. A frequency of the alternating voltages corresponds, in at least one operating state, to a rotational speed of the rotor 38a. For this purpose, the commutator 36a has a sensor 40a that measures an orientation and / or a rotational speed of the rotor 38a. The sensor 40a measures a rotational speed of the rotor 38a via a coil of the electric motor 30a. A commutator and / or an electric motor could also have another sensor for determining the rotational speed that would be deemed appropriate by a person skilled in the art.

[0021] How Fig. 3 shows that the handheld power tool 10a includes a computing unit 34a. The computing unit 34a is designed as a microcontroller. The computing unit 34a regulates the AC voltage, which the motor driver 32a supplies to the electric motor 30a, via the motor driver 32a. Alternatively, a computing unit could control a DC voltage. The rotational power delivered by the electric motor 30a to the tool spindle 12a depends on the AC voltage of the motor driver 32a. The electric motor 30a consumes a maximum power of between 15 watts and 150 watts to drive the tool spindle 12a, in this embodiment a maximum of 40 watts. In this embodiment, the motor driver 32a and the computing unit 34a are designed separately. Alternatively, a motor driver and a computing unit could be arranged on a common circuit board.Before driving the tool spindle 12a, the computing unit 34a moves the rotor 38a of the electric motor 30a into a predetermined starting position. During starting, the computing unit 34a accelerates the rotor 38a according to a predetermined acceleration function. Here, the computing unit 34a accelerates the rotor 38a linearly.

[0022] The drive unit 14a has a sensor 42a that measures an orientation angle and / or a rotational speed of the tool spindle 12a. This sensor 42a is partially connected to the tool spindle 12a in a rotationally fixed manner. Thus, the drive unit 14a has a total of two sensors 40a, 42a for measuring a rotational speed. The computing unit 34a regulates the rotational speed of the tool spindle using the sensor 42. The drive unit 14a drives the tool spindle 12a at a continuously adjustable speed. The computing unit 34a compares a characteristic of a rotational speed of the tool spindle 12a with a characteristic of a rotational speed of the rotor 38a of the electric motor 30a. Alternatively, a computing unit could link a characteristic of a rotational speed of the tool spindle 12a with a characteristic of a power consumption of the electric motor 30a. The computing unit 34a detects whether the hose coupling 22a slips.In this case, the computing unit 34a brakes the rotor 38a of the electric motor 30a via the motor driver 32a. Furthermore, the computing unit 34a brakes the rotor 38a when an operator reduces a target speed. Furthermore, the computing unit 34a brakes the rotor 38a when an operator sets the target speed to zero. Furthermore, the computing unit 34a switches off the electric motor 30a if it detects a load jump on the tool spindle 12a that exceeds a limit value. Such a load jump occurs in particular when the insert tool 26a jams. Alternatively, a computing unit 34a could brake the rotor 38a of the electric motor 30a in this case.

[0023] The hand tool housing 20a of the hand tool 10a encloses the electric motor 30a without any ventilation openings. The hand tool housing 20a conducts waste heat from the electric motor 30a to a surface of the hand tool housing 20a. The hand tool housing 20a has a sealant (not shown in detail). The sealant prevents liquid, humidity, air, dust, and dirt from penetrating an interior space 44a of the hand tool housing 20a.

[0024] The handheld tool housing 20a has four housing elements 46a, 48a, 50a, 52a. A first and a second of the housing elements 46a, 48a are designed as half-shells. The first and second housing elements 46a, 48a extend parallel to a rotational axis 54a of the tool spindle 12a along the battery 18a, the drive unit 14a, and the tool spindle 12a. The first and second housing elements 46a, 48a are connected to one another along a plane that runs parallel to a rotational axis 54a of the tool spindle 12a. The first and second housing elements 46a, 48a are laser-welded to one another. The third housing element 50a delimits the interior 44a of the handheld tool housing 20a on a side facing away from the tool chuck 16a. The fourth housing element 52a delimits the interior space 44a of the hand tool housing 20a on a side facing the tool chuck 16a.To this end, the third and fourth housing elements 50a, 52a each partially enclose the first and second housing elements 46a, 48a on a plane oriented perpendicular to the rotation axis 54a. The third and fourth housing elements 50a, 52a are thus designed as a cover. The third and fourth housing elements 50a, 52a are laser-welded to the first and second housing elements 46a, 48a. Thus, screwing is not required for the hand tool housing 20a.

[0025] Fig. 4 shows the hand tool 10a in a top view. The Fig. 5 shows the handheld power tool 10a in a side view. The handheld power tool housing 20a has a plane of symmetry 56a that runs parallel to the rotational axis 54a of the tool spindle 12a. The handheld power tool housing 20a comprises a battery region 58a, a handle region 60a, and a lighting unit region 62a. The handheld power tool housing 10a has an oval cross-section perpendicular to the rotational axis 54a. The handheld power tool housing 10a comprises a top side 64a and a bottom side 66a. An operating unit 68a of the handheld power tool 10a is arranged on the top side 64a. The handheld power tool housing 10a has a total length 70a parallel to a rotational axis 54a of less than 250 mm. Here, the total length is 180 mm. The handheld power tool 10a has a total weight of less than 150 g. Here the total weight is 128 g.A center of gravity 72a of the handheld power tool 10a is spaced less than 40 mm in the axial direction from the control unit 68a of the handheld power tool 10a. Here, the center of gravity 72a of the handheld power tool 10a is spaced 30 mm from the control unit 68a in the axial direction away from the tool chuck 16a.

[0026] The battery area 58a has a diameter of less than 35 mm on a battery plane. The battery plane intersects the battery 18a and is aligned perpendicular to the rotation axis 54a. Here, the battery area 58a has a diameter 74a of approximately 29 mm on the battery plane parallel to the symmetry plane 56a. The top side 64a has a distance 76a of 13 mm from the rotation axis 54a on the battery plane and parallel to the symmetry plane 56a. The bottom side 66a has a distance 78a of 16 mm from the rotation axis 54a on the battery plane and parallel to the symmetry plane 56a. Perpendicular to the symmetry plane 56a, the battery area 58a has a diameter 80a of 26 mm.

[0027] The grip region 60a has a rubber-elastic, anti-slip grip material on its outer side. The grip region 60a extends, on average, parallel to the rotational axis 54a of the tool spindle 12a. The grip region 60a comprises a tapered region 82a, a handle stop region 84a, and a constriction maximum 86a. The constriction maximum 86a is arranged between the tapered region 82a and the handle stop region 84a. The constriction maximum 86a is arranged on a plane oriented perpendicular to the rotational axis 54a. At the constriction maximum 86a, the grip region has a minimum diameter 90a. The diameter 88a at the constriction maximum 86a parallel to the symmetry plane 56a is 16.1 mm. A diameter 90a at the constriction maximum 86a perpendicular to the symmetry plane 56a is 15.6 mm. The constriction maximum 86a is spaced less than 22 mm from a workpiece side 92a of the hand tool housing 20a.In this embodiment, the maximum constriction is located 19 mm from the workpiece side 92a. A portion of the gripping area 60a is spaced less than 10 mm from the workpiece side 92a.

[0028] The tapered region 82a is arranged between the constriction maximum 86a and the accumulator region 58a. It has an extension 94a parallel to the rotation axis 54a of 50 mm. On the underside 66a, it tapers at an angle 96a of 10 degrees relative to the accumulator region 58a. Relative to the plane of symmetry 56a, the tapered region 82a tapers at an angle 98a of approximately 6 degrees. The handle stop region 84a is arranged on a side of the constriction maximum 86a facing the tool chuck 16a. It has an extension 100a parallel to the rotation axis 54a of 11 mm. It widens from the constriction maximum 86a in the direction of the tool chuck 16a. It widens according to an elliptic curve 102a, which appears reasonable to the expert, here with ellipse axes of 11 mm and 19 mm respectively.The handle stop region 84a has a maximum diameter 104a that is less than 1.2 times the diameters 88a, 90a of the constriction maximum 86a. Here, the handle stop region has the maximum diameter 104a, approximately 1.15 times the diameter 88a, 90a of the constriction maximum 86a.

[0029] The lighting unit region 62a is arranged between the handle stop region 84a and the tool chuck 16a. The lighting unit region 62a is essentially cylindrical. The lighting unit region 62a has a diameter 104a of 18.5 mm radially to the rotation axis 54a. The diameter 104a of the lighting unit region 62a corresponds to the maximum diameter 104a of the handle stop region 84a. The lighting unit region 62a delimits the interior space 44a of the hand tool housing 20a in the direction of the tool chuck 16a. The lighting unit region 62a of the hand tool housing 10a encloses a lighting unit 106a of the handheld power tool 10a on at least one plane perpendicular to the rotation axis 54a. The lighting unit 106a illuminates a work area of ​​the workpiece in at least one operating state (not shown in detail).

[0030] The lighting unit 106a comprises an optical element 108a, which is partially formed integrally with the hand tool housing 20a. Specifically, the optical element 108a is formed integrally with the fourth housing element 52a, which delimits the interior space 44a of the hand tool housing 20a on a side facing the tool chuck 16a. Thus, the optical element 108a is provided to secure the first and second housing elements 46a, 48a. The fourth housing element 52a forms part of the lighting unit region 62a. The optical element 108a has lenses (not shown in detail) that focus a luminous flux emitted by illuminants 110a, 112a of the lighting unit 106a. Furthermore, the optical element 108a has a diffuser (not shown in detail) that scatters the luminous flux during operation, whereby a shadow of the inserted tool 26a has smooth transitions.Alternatively, the optical element 108a could comprise only lenses and / or lenses could be formed integrally with a diffuser.

[0031] The lighting unit 106a has eight lamps 110a, 112a. The lighting unit 106a also has a lamp carrier 114a. The lamp carrier 114a secures the lamps 110a, 112a on an axial plane of the tool spindle 54a, arranged at an angle 116a of 45 degrees to one another relative to the tool spindle 54a. They are evenly distributed around the rotation axis 54a. The lamp carrier 114a is designed as a printed circuit board. It has an annular shape. The lamp carrier 114a surrounds the tool spindle 12a by 360 degrees on at least one plane.

[0032] The lighting unit 106a has a delay unit (not shown in detail here) that delays the switching off of the lamps 110a, 112a by a specified time after the drive unit 14a is switched off. The time can be set by an operator. The delay unit is embodied as a calculation routine of the calculation unit 34a. The delay unit begins to dim the lamps 110a, 112a, for example, two seconds after the drive unit 14a is switched off. Within two seconds, the delay unit dims the lamps 110a, 112a until they no longer emit any luminous flux.

[0033] The illuminants 110a, 112a are partially designed as white-emitting illuminants 110a. Furthermore, the illuminants 110a, 112a are partially designed as colored illuminants 112a. The white-emitting illuminants 110a are designed as white-emitting light-emitting diodes. The colored illuminants 112a are designed as RGB light-emitting diodes. This means that they are designed to emit red, green, and blue light. In this exemplary embodiment, the lighting unit 106a has six white-emitting illuminants 110a and two colored illuminants 112a. The colored illuminants are designed to emit light in different colors with variable color components.

[0034] The handheld power tool 10a has a display unit 118a. The colored lamps 112a are part of the display unit 118a. Thus, the display unit 118a is partially formed integrally with the lighting unit 106a. During operation, the colored lamps 112a illuminate the work area in a color that depends on a specific parameter. Thus, the display unit 118a is designed to output two different parameters. The computing unit 34a controls the output of the parameters. The operator can select which parameter should be output. A single parameter can also be output simultaneously by both colored lamps 112a.Selectable parameters are parameters that appear useful to a person skilled in the art, but in particular a temperature of the drive unit 14a and / or the battery 18a, a speed of the tool spindle 12a, a charge level of the battery 18a, a contact pressure of the inserted tool on the workpiece, a power consumption of the drive unit 14a, and / or a temperature or charge level warning when a threshold value is exceeded. The handheld power tool 10a has a display (not shown in detail), here an OLED display, which shows the operator a type of output parameter. The handheld power tool 10a has a temperature sensor 119a, which measures a temperature of the electric motor 30a during operation.

[0035] The handheld power tool 10a has a further display unit 120a, which is arranged at an end of the handheld tool housing 20a facing away from the tool chuck 16a. The further display unit 120a has four green-illuminating lamps 122a and four red-illuminating lamps 124a. Two differently colored lamps 122a, 124a each illuminate through a recess 126a of the handheld tool housing 10a. As an alternative to the two display units 118a, 120a, a handheld power tool 10a could also have only one of the two display units 118a, 120a.

[0036] The handheld power tool 10a has the operating unit 68a with two operating elements 128a, 130a. The handheld tool housing 20a mounts the operating elements 128a, 130a. The first of the operating elements 128a is designed as a capacitive button. During operation, the operator stops and starts a drive of the tool spindle 12a using the first operating element 128a. The first operating element 128a is arranged at a distance of less than 30 mm from the constriction maximum 86a of the handle area 60a, namely 24 mm. The first operating element 128a is arranged on the plane of symmetry 56a. The second of the operating elements 130a comprises two capacitive buttons. The two buttons are spaced 132a apart by 8 mm and are arranged symmetrically to the plane of symmetry 56a.

[0037] During operation, the operator can select a speed of the tool spindle 12a using the second control element 130a. The second control element 130a is provided to output a parameter for controlling a speed of the tool spindle 12a. By simultaneously pressing the two buttons, the operator can select a parameter output to the display units 118a, 120a. The second control element 130a is arranged at a distance of less than 80 mm from the constriction maximum 86a of the grip area 60a, namely 50 mm. The buttons only have an unactuated stable state, i.e., they do not lock in a pressed state. The control unit 68a detects a forceless touch by an operator. Alternatively or additionally, the control unit 68a could have partially movable buttons, in particular with a mechanically closing contact.

[0038] The handheld power tool 10a has a charging energy input 134a. The charging energy input 134a is designed as a USB interface. The charging energy input 134a is arranged on a side of the handheld tool housing 20a facing away from the tool chuck 16a. The charging energy input 134a is intended for data transmission. Specifically, the computing unit 34a can be adjusted via the charging energy input 134a using a computer (not shown in detail). The operator can configure a speed range adjustable using the operating elements 130a, configure a characteristic displayed by the colored lamps 124a, and make other settings deemed appropriate by a person skilled in the art. Furthermore, the operator can transfer operating data deemed appropriate by a person skilled in the art, such as operating hours and / or work processes of the handheld power tool 10a, from the handheld power tool 10a to the computer via the charging energy input 134a.

[0039] The handheld power tool 10a has a pressure sensor (not shown in detail) that detects the pressure exerted by the insert tool 26a on the workpiece during operation. The pressure sensor is arranged on one of the bearings 24a of the tool spindle 12a. The display unit 118a displays the pressure exerted by the insert tool 26a on the workpiece during an operating state. This enables particularly precise workpiece machining.

[0040] The handheld power tool 10a has a proximity sensor 136a that detects an approach of the insert tool 26a to the workpiece. The proximity sensor 136a is designed as an optical sensor. Alternatively, a proximity sensor could be designed as a capacitive sensor that detects a capacitance of the insert tool 26a. Upon an intended approach, which can be set in particular by an operator, the computing unit 34a automatically starts a drive of the tool spindle 12a. This enables particularly comfortable working with frequent stops, in particular for checking a machining result. Alternatively or additionally, the handheld power tool could have a motion sensor that detects a speed of a movement of the handheld power tool 10a relative to the workpiece. In particular, a display unit could output the speed.Furthermore, the handheld power tool could have an acceleration sensor, a gyroscope, and / or a position sensor. In particular, a computing unit could be provided to use these sensors to determine a blockage of an insert tool and / or information about a machining process, and to output this information, in particular, via a display unit.

[0041] In the Fig. 7 and Fig. 8 shows two further embodiments of the invention. The following descriptions and the drawings are essentially limited to the differences between the embodiments, whereby with regard to components with the same designation, in particular with regard to components with the same reference numerals, reference is generally also made to the drawings and / or the description of the other embodiment of the Fig. 1 to 6. To distinguish the embodiments, the letter a is added to the reference numerals of the embodiment in the Fig. 1 to 6. In the example of the Fig. 7 and Fig. 8 the letter a is replaced by the letter b.

[0042] Fig. Figure 7 shows a handheld power tool 10b with a tool spindle 12b and a drive unit 14b. In an operating state, the drive unit 14b drives the tool spindle 12b at a speed greater than 10,000 rpm. -1The handheld power tool 10b comprises an operating unit 68b, which detects a forceless touch by an operator during operation. The operating unit 68b detects the approach of a body part of the operator. For this purpose, the operating unit 68b has an operating element 130b with two capacitive sensors 138b and an electrically conductive operating surface 140b. The operating surface 140b is strip-shaped. It has an aspect ratio greater than one to five. The sensors 138b detect where an operator touches the operating surface 140b. The sensors 138b output this value as a parameter of an operating state. The operating unit 68b is thus intended to detect more than three different operating states. A computing unit 34b of the hand-held power tool 10b adjusts a target speed of the tool spindle 12b when the operator moves a touch point on the operating surface 140b.The computing unit 34b starts or stops a drive of the tool spindle 12b when the operator taps the operating surface 140b. The operating unit 68b has a display unit 142b, which displays a selected parameter of an operating state during operation. The display unit 142b illuminates the operating surface 140b.

[0043] Fig.8 shows a system 144b with a handheld tool charger 146b and the handheld power tool 10b. The handheld power tool 10b has a charging energy input 134b with two charging contacts 148b. The charging energy input 134b is arranged on a side of the handheld tool housing 20b facing the tool chuck 16b. When charging a battery 18b of the handheld power tool 10b, the handheld tool charger 146b contacts the charging contacts 148b. For this purpose, the handheld tool charger 146b has spring-loaded contacts (not shown in detail). When charging the handheld power tool 10b, the handheld tool charger 146b transfers electrical energy to the handheld power tool 10b via the charging contacts 148b. Alternatively or additionally, a handheld tool charger and a handheld power tool could each have a coil that transfers energy from the handheld tool charger to the handheld power tool during a charging process.

[0044] The hand tool charger 146b encloses the hand tool 10b on a plane by more than 180 degrees during a charging process. Here, the hand tool charger 146b encloses the hand tool 10b on the plane by 360 degrees. The hand tool charger 146b encloses the hand tool housing 20b of the hand tool 10b on a side facing the tool chuck 16b.

Claims

[1] Hand-held power tool with at least one tool spindle (12a; 12b), with a drive unit (14a; 14b) which has a brushless electric motor (30a), with a rechargeable battery (18a; 18b), in particular a lithium-based rechargeable battery, which is provided for supplying the drive unit (14a; 14b) with electrical energy, and with a hand-held power tool housing (20a) which has a housing element (46a, 48a) extending substantially parallel to a rotational axis (54a) of the tool spindle (12a) along the drive unit (14a) and the tool spindle (12a), wherein the drive unit (14a, 14b) is connected to the tool spindle (12a; 12b) in a gearless manner and is provided for rotating the tool spindle (12a; 12b) at a speed greater than 10,000 min -1to drive, wherein the drive unit (14a; 14b) receives a direct voltage for supplying the electric motor (30a) in at least one operating state, wherein the drive unit (14a; 14b) has an electronic commutator (36a) which is provided to convert the direct voltage at least into an alternating voltage, wherein the drive unit (14a; 14b) is provided to brake a rotor (38a) of the electric motor (30a) via a motor driver (32a). [2] Hand tool according to claim 3, characterized by that the commutator (36a) is provided to convert the DC voltage dependent on a speed into an AC voltage. [3] Hand tool according to one of the preceding claims, characterized by that the electric motor (30a) has an internal rotor (38a). [4] Hand tool according to one of the preceding claims, characterized bythat the drive unit (14a; 14b) has a maximum power between 15 watts and 150 watts. [5] Hand tool according to one of the preceding claims, characterized by a hose coupling (22a; 22b) connecting the drive unit (14a; 14b) to the tool spindle (12a; 12b).

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