Hand-held power tool

Abstract

A hand-held power tool, including: a drive circuit for providing an adjustment signal as a function of actuation of a button, a control apparatus for adjusting a drive current for an electric motor of the hand-held power tool as a function of the adjustment signal, wherein the control apparatus is connected to an electrical energy source for operating the hand-held power tool via a first electrical line arrangement, the drive circuit is connected to the control apparatus via a second electrical line arrangement, a drive current line carrying the drive current for the electric motor is routed via an interruption switch, coupled to the button, for interrupting the drive current, and wherein an interference-suppression capacitor is connected to the drive power line via a first node and to the second electrical line arrangement via a second node.

Claims

1-15. (canceled)

16. A hand-held power tool comprising: a drive circuit for providing an adjustment signal as a function of actuation of a button; a controller for adjusting a drive current for an electric motor of the hand-held power tool as a function of the adjustment signal, the controller being connected to an electrical energy source for operating the hand-held power tool via a first electrical line arrangement, the drive circuit being connected to the controller via a second electrical line arrangement; a drive current line carrying the drive current for the electric motor being routed via an interruption switch, coupled to the button, for interrupting the drive current; and an interference-suppression capacitor being connected to the drive power line via a first node and to the second electrical line arrangement via a second node.

17. The hand-held power tool as recited in claim 16 wherein the interference-suppression capacitor is directly connected to the second electrical line arrangement.

18. The hand-held power tool as recited in claim 16 wherein the interference-suppression capacitor is connected to a neutral conductor potential or to a ground potential via the second electrical line arrangement.

19. The hand-held power tool as recited in claim 16 wherein the interruption switch is connected to the controller via a first section of the drive power line and is connected to the electrical energy source via a second section of the drive power line, wherein the interference-suppression capacitor is connected to the second section of the drive power line via the first node.

20. The hand-held power tool as recited in claim 16 wherein the interruption switch is opened or closed as a function of actuation of the button.

21. The hand-held power tool as recited in claim 16 wherein the drive circuit, the button, the interference-suppression capacitor and the interruption switch are part of a common component.

22. The hand-held power tool as recited in claim 16 wherein the drive circuit includes a circuit board on which at least one detector, coupled to the button, for detecting the actuation of the button is integrated.

23. The hand-held power tool as recited in claim 22 wherein the interference-suppression capacitor is integrated on the circuit board.

24. The hand-held power tool as recited in claim 23 wherein the interference-suppression capacitor is designed as an SMD component.

25. The hand-held power tool as recited in claim 16 wherein the drive circuit is integrated in a handle of the hand-held power tool and the button is actuatable from the outside of the handle.

26. The hand-held power tool as recited in claim 16 wherein the controller is configured to provide an operating voltage for the drive circuit via the second electrical line arrangement.

27. The hand-held power tool as recited in claim 16 wherein the second electrical line arrangement has lines with a maximum cross section of 1 mm.sup.2.

28. The hand-held power tool as recited in claim 27 wherein the second electrical line arrangement has lines with a maximum cross section of 0.5 mm.sup.2.

29. The hand-held power tool as recited in claim 28 wherein the second electrical line arrangement has lines with a maximum cross section of 0.33 mm.sup.2.

30. The hand-held power tool as recited in claim 16 wherein the drive current line has a line cross section of between 1.5 mm.sup.2 and 5 mm.sup.2.

31. The hand-held power tool as recited in claim 16 wherein the interference-suppression capacitor has a capacitance of between 0.1 and 1 F.

32. The hand-held power tool as recited in claim 16 wherein the interference-suppression capacitor is designed as a class X1 or a class X2 capacitor.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0046] The following description explains the invention with reference to exemplary embodiments and figures, in which:

[0047] FIG. 1 shows a schematic view of a hand-held power tool; and

[0048] FIG. 2 shows a schematic view of internal wiring of a hand-held power tool.

[0049] Identical or functionally identical elements are indicated by the same reference signs in the figures, unless stated otherwise.

DETAILED DESCRIPTION

[0050] FIG. 1 schematically shows a hand-held power tool 1, which is designed as a hammer drill in this example. The hammer drill 1 has a tool fitting 2 into which a drill bit 3 can be inserted as a tool. A primary drive of the hammer drill 1 forms an electric motor 4 which drives an impact mechanism 5 and a drive shaft 6. A user can guide the hammer drill 1 by means of a handle 8 and put the hammer drill 1 into operation by means of a button 12. During operation, the hammer drill 1 rotates the drill bit 3 continuously about a working axis and in so doing can hit the drill bit 3 along the working axis into a substrate.

[0051] An electrical arrangement 10, which fulfills various functions, is arranged in the handle 8. A drive circuit 11 is configured to provide an adjustment signal SIG (see FIG. 2) as a function of actuation of the button 12. For this purpose, the drive circuit 11 is coupled to a control apparatus 20 by means of the second electrical line arrangement 15. In particular, the adjustment signal SIG is transmitted via the second electrical line arrangement 15. The drive circuit 11 provides the adjustment signal SIG as a function of a current position of the button 12, which is designed in particular as a trailing button. The combination of the button 12 and the drive circuit 11 can also be referred to as a rotation speed controller. The electrical arrangement 10 further comprises an interruption switch 14 which is arranged in a drive current line 16A, 16B which carries the drive current for the electric motor 4. The interruption switch 14 is coupled to the button 12 and is opened or closed as a function of actuation of the button 12. The interruption switch 14 ensures that the electric motor 4 is only supplied with power when the button 12 is actuated. In addition, the arrangement 10 comprises an interference-suppression capacitor 13 which is connected at one end to the drive power line 16A, 16B and at the other end to the second electrical line arrangement 15. In this example, the connection to the second electrical line arrangement 15 is implemented via the drive circuit 11.

[0052] The tool fitting 2 has a sleeve into which one end of the drill bit 3 can be inserted. The torque is provided by the electric motor 4 and passed on to the sleeve via a drive train. The drive train includes, for example, the output shaft 6 and a transmission between the motor 4 and the drive shaft 6. The transmission can adapt, for example, a rotation speed of the motor 4 to a desired rotation speed of the drill bit 3.

[0053] The rotation speed and/or the torque of the electric motor 4 is adjusted by a control apparatus 20 as a function of the adjustment signal SIG. It can also be said that the control apparatus 20 controls the electric motor and/or regulates it to a target value. The control apparatus 20 is coupled via a first electrical line arrangement 21 to a connection terminal 24 which can be coupled to a power supply system by means of a plug 23. As an alternative, the hammer drill 1 can also be supplied with power via a rechargeable battery. Power consumption by the electric motor 4 during operation, the operating value, preferably corresponds approximately to the rated power of the electric motor 4, as a result of which an optimal ratio of power and weight is obtained. The electric motor 4 is, in particular, a mechanically commutating universal motor and/or an electronically commutating motor.

[0054] FIG. 2 shows a schematic view of an exemplary embodiment of the internal wiring of a hand-held power tool 1, for example the hammer drill 1 from FIG. 1. It is, for example, a mains-operated hand-held power tool 1 which can be connected to a power supply system via a plug 23. In this example, a phase conductor L and a neutral conductor N are provided via a connection terminal 24, which is arranged in particular in a housing 9 (see FIG. 1) of the hand-held power tool 1.

[0055] A control apparatus 20 is connected to the connection terminal 24 and the two phases L, N of the power supply system via a first electrical line arrangement 21. The control apparatus 20 can therefore be supplied with electrical energy as soon as the plug 23 is coupled to the power supply system. The first electrical line arrangement 21 comprises lines with a cross section of up to 5 mm.sup.2. The control apparatus 20 comprises, for example, a transformer which is configured to generate and provide a low voltage. The low voltage is, for example, one or more voltage values of between 1 V and 20 V. For example, integrated components, such as a control unit (ASIC: application specific integrated circuit, PLC: programmable logic controller, CPU: central processing unit), memory units (ROM: read only memory, RAM: random access memory), display apparatuses (LCD: liquid crystal display), lighting devices (LED: light emitting diode) and the like, can be operated with the low voltage.

[0056] In particular, a drive circuit 11 is connected to the control apparatus 20 via a second electrical line arrangement 15 and is fed with the low voltage via this. In this example, the second electrical line arrangement 15 comprises three separate lines N, V and SIG, wherein the lines N and V correspond to the poles of the low voltage and the adjustment signal SIG is transmitted via the third line. In this example, the low voltage relates to the neutral conductor potential of the power supply system, but this does not necessarily have to be the case. In embodiments, yet further lines can be provided, for example in order to provide additional potentials. The drive circuit 11 is coupled to a button 12 and is configured to provide the adjustment signal SIG as a function of actuation of the button 12. For this purpose, the drive circuit 11 comprises, in particular, a detection unit 17 which, in this example, is designed as a voltage converter. The lines N, V, SIG of the second electrical line arrangement 15 have, for example, a line cross section of 0.33 mm.sup.2.

[0057] The button 12 is further coupled to an interruption switch 14. When the button 12 is actuated, for example depressed by 10%, the interruption switch 14 closes. The interruption switch 14 is connected to the control apparatus 20 via a first section 16A of the drive power line and is connected to the connection terminal 24 and the phase conductor L of the power supply system via a second section 16B of the drive power line. The drive power line 16A, 16B has a cross section of 3 mm.sup.2. An interference-suppression capacitor 13 is connected via a first node K1 to the second section 16B of the drive power line and the interference-suppression capacitor 13 is connected to the second electrical line arrangement 15, in this example to the neutral conductor potential N which is looped through the drive circuit 11, via a second node K2. The interference-suppression capacitor 13, which has a capacitance of 0.22 F and can withstand a peak voltage of 4000 V (class X1), is therefore configured to filter high-frequency voltage fluctuations which can occur during operation of the electric motor 4 (see FIG. 1).

[0058] The drive circuit 11, the button 12, the interference-suppression capacitor 13 and the interruption switch 14 preferably form a common component 10. In preferred embodiments, the drive circuit 11 is designed as a circuit board, wherein the interference-suppression capacitor 13 is integrated on the circuit board, preferably as an SMD component (SMD: surface-mounted device). The drive circuit 11 can have further electronic components or can be configured for their operation, such as an LED, a torque sensor, an acceleration sensor, a temperature sensor and the like, for example.

LIST OF REFERENCE SIGNS

[0059] 1 Hand-held power tool (hammer drill) [0060] 2 Tool fitting [0061] 3 Tool [0062] 4 Motor [0063] 5 Impact mechanism [0064] 6 Drive shaft [0065] 7 Rechargeable battery [0066] 8 Handle [0067] 9 Housing [0068] 10 Arrangement [0069] 11 Drive circuit [0070] 12 Button [0071] 13 Interference-suppression capacitor [0072] 14 Interruption switch [0073] 15 Second electrical line arrangement [0074] 16A Section [0075] 16B Section [0076] 17 Voltage divider [0077] 20 Control apparatus [0078] 21 First electrical line arrangement [0079] 23 Plug [0080] 24 Connection terminal [0081] K1 Node [0082] K2 Node [0083] L Phase conductor [0084] N Neutral conductor [0085] SIG Adjustment signal [0086] V Low voltage potential