EP1374653B1 - Control device for an electric motor - Google Patents

Description

The invention relates to a device for controlling a Electric motor according to the preamble of patent claim 1.

Such a device is mainly in one Power tool used. In particular, it can be to a cordless power tool with a brushless DC motor act.

In power tools, it is known to open the control circuit to arrange a board in the housing of the power tool. In the handle of the housing is still on electrical switch for manual operation of the Power tool. Finally, in the case are still the Voltage supply to the electric motor serving Power semiconductors added. The control electronics, the Switches and the power semiconductors are together as well with the electric motor and possibly with the battery through connected electrical lines. As a disadvantage has while the associated with the wiring effort exposed. Due to the limited installation space in the Housing of the power tool is the accommodation of the Facility often difficult. Furthermore, the lines also distortions of the means of power semiconductors cause switched motor current, so that the electric motor is operated incorrectly, which ultimately damages and Failure of the power tool can cause.

From US 5,619,085 A is further an electric motor with a Housing known, the end-side housing closure as a Heat sink is formed. Inside the case is a PCB thermally conductive arranged directly on the heat sink. On the circuit board are the control electronics as well the power transistors for the electric motor. At this Arrangement there is a risk that the of the Power transistors generated insufficient heat from the Inside the housing can be dissipated, bringing it to the Operational safety is lacking.

The invention is based on the object, a device to create an electric motor, the compact is formed and so even in limited installation spaces can be accommodated. In particular, should Control device a reliable operation of the Electric motor permit.

This object is in a generic device for Control of an electric motor by the characterizing Characteristics of claim 1 solved.

The drive device according to the invention has a Support plate, which is for example a Circuit board can act, at least part of the Control circuit, in particular electrical and / or electronic components as well as the electrical and / or electronic components connecting conductor tracks of the Control circuit, is arranged on the support plate. Of the Power semiconductor is on a on the carrier plate fixed support member arranged, whereby the Control device for limited installation spaces is suitable.

In a further embodiment, the inventive Control device, a support plate, wherein at least one Part of the control circuit, in particular electrical and / or electronic components as well as the electrical and / or electronic components connecting conductor tracks of the Control circuit, is arranged on the support plate. The Support plate consists of a metal part, whose the Components and the conductor tracks facing surface with an insulating coating is provided, such that the Components, the conductor tracks o. The like. In turn, on the Coating are located. The metal part also serves as Heatsink, bringing the heat loss even at high Services is safely deductible.

Further embodiments of the invention are the subject of Dependent claims.

These versions can be used for particularly high currents a plurality of power semiconductors arranged on the carrier element be. For DC applications are usually called Power semiconductors then used several MOS-FETs. For example, a drive circuit for a cordless power tool have six MOS-FETs.

In a further embodiment, the support element for the Power semiconductors designed as a heat sink. This is ensured that especially the s.der power semiconductors resulting higher heat loss is safely dissipated and an influence of the control circuit by this Loss of heat is excluded. The carrier element can in turn pressed into the carrier plate and / or be soldered.

Conveniently, a battery is used in DC applications for power supply of the electric motor. It lends itself then to simplify the power supply, that the Support plate is located near the battery, namely Preferably such that the power semiconductor and / or the carrier element with the power semiconductor the battery is facing. An attachable contact of the battery in simple way is made by the fact that at the Support plate plug contacts, in particular in the manner of Contact brackets, for example, "tulip" brackets, are formed, are arranged. Another simplification can be achieved by the plug contacts on the Carrier plate plug-on and / or be latched. Therefor offers an adapter.

In order to keep the leads for the power supply as short as possible, is in more Embodiment of the power semiconductor and / or the carrier element for the Power semiconductor directly to the battery facing edge of the carrier plate arranged. Then the power semiconductor and / or the carrier element in direct make electrical contact with the plug contacts for the battery. To simplify the Manufacture are the plug contacts in one piece in the carrier plate and / or the Integrated support element. The capacitors of the control circuit are more compact Assembly soldered directly to the plug contact. Furthermore, the capacitors of the Control circuit to be arranged on the support plate, between the Power semiconductor and / or the carrier element for the power semiconductor and the Plug contacts.

In a further embodiment, the control circuit is a setpoint for setting a associated speed supplied to the electric motor. For generating the setpoint is located on the support plate, a sensor element, such as a potentiometer, a Hall element, a magnetoresistive element or another element. To protect the Sensor element, this can be arranged in a housing, for this purpose expediently offers the housing of an electrical switch. The switch has then an especially designed in the manner of a pusher actuator for the Actuation of the sensor element, wherein the actuator on the housing of the switch is arranged. Furthermore, in the electrical switch, a contact system, the Switching the power supply of the electric motor and possibly the Control circuit is used, be arranged. The contact system is also using the Actuator actuated. Thus, the carrier plate serves for recording and Attachment of the electrical switch. In extension, it is advantageous if then too yet another electrical switch for switching between right / left rotation of the electric motor is arranged on the carrier plate. In this further switch can it is a micro and / or snap switch, with the other Switch an actuator, for example, designed in the manner of a slider is, acts.

Due to the compact design, the drive device according to the invention Advantageously in the handle of a power tool in the manner of a prefabricated Insert module, in which case the actuator for manual operation of the Handle shell protrudes. Such a control device can alternatively be in the battery arrange the power tool so that after inserting the battery into the handle of the Power tool, the actuator protrudes from the handle shell. Just as well when inserting the battery, the already located in the handle shell actuator in Linkage come to the control device.

The advantages achieved by the invention are in particular that the Control device compact and therefore in tight spaces of the Handle tray of power tools is to accommodate. In addition, there is a simple Mounting as well as a reduction of the wiring effort in the power tool, since in the control device otherwise separately assembled parts already summarized are. Furthermore, this results in a significant cost savings for the Power tool manufacturer. Finally, it should be stressed that the Control device according to the invention a higher reliability than previous ones Having facilities, so that related damage to the power tool is effectively prevented.

Fig. 1

einen Schnitt durch ein Akku-Elektrowerkzeug,

Fig. 2

die Ansteuereinrichtung entsprechend einer ersten Ausführung aus Fig. 1 als Einzelteil in Draufsicht,

Fig.3

die Ansteuereinrichtung aus Fig. 2 in Seitenansicht,

Fig. 4

das Trägerelement mit Leistungshalbleiter als Einzelteil in einer Seitenansicht,

Fig. 5

das Trägerelement mit Leistungshalbleiter als Einzelteil in einer weiteren Seitenansicht und

Fig. 6

die Ansteuereinrichtung wie in Fig. 2 entsprechend einer zweiten Ausführung.

Embodiments of the invention are illustrated in the drawings and will be described in more detail below. Show it

Fig. 1

a section through a cordless power tool,

Fig. 2

the drive device according to a first embodiment of FIG. 1 as an individual part in plan view,

Figure 3

the control device of FIG. 2 in side view,

Fig. 4

the carrier element with power semiconductor as an individual part in a side view,

Fig. 5

the carrier element with power semiconductor as a single part in a further side view and

Fig. 6

the drive device as in Fig. 2 according to a second embodiment.

In Fig. 1 is a power tool 22 with a device 1 for driving a Electric motor 23 shown. For example, the electric motor 23 may be a act brushless DC motor in a cordless power tool. The in Fig. 2 and 3 shown as an item driving device 1 has at least one Power semiconductor 3 for controllably applying an electrical voltage to the Electric motor 23 and a control circuit 4 for controlling the power semiconductor. 3 The control circuit 4 includes electrical and / or electronic components 5 and the this connecting tracks 6. Next, the drive means 1 a Support plate 2, wherein at least a part of the control circuit 4 on the support plate. 2 is arranged.

According to a first embodiment according to FIGS. 2 and 3, the power semiconductor 3 is on a carrier element 7 is arranged. The carrier element 7 is in turn on the carrier plate 2 attached, as can be seen with reference to FIG. 4, whereby a special flexibility in the Arrangement of the power semiconductor 3 in a small footprint on the support plate. 2 is achieved. The carrier plate 2 may be, for example, a printed circuit board act. Of course, the power semiconductor 3 also directly on the carrier plate 2, if the space available there is sufficient.

According to a further second embodiment shown in FIG. 6, the carrier plate 2 from a metal part 9, facing the components 5 and the conductor tracks 6 Surface is provided with an electrically insulating coating 8. The components 5, the conductor tracks 6 o. The like. Are in turn on the coating 8. The metal part 9 simultaneously serves as a heat sink, which means a separately on the control device. 1 attached heat sink is superfluous.

In the second embodiment, the power semiconductor 3 can also be on a Carrier element 7 may be arranged according to FIG. 2, wherein the carrier element 7 then is fixed on the support plate 2. However, here also on the support element. 7 are omitted, which is shown in Fig. 6. In this case, the power semiconductor 3 be arranged on the coating 8 of the metal part 9. Likewise, the Coating 8 a recess 10 included, on which the power semiconductor directly on the metal part 9 is fixed, as shown by the two power semiconductors located on the left 3 'is shown. The attachment of the power semiconductor 3, 3 'takes place for example by Soldering.

Further embodiments, which are usable in both embodiments, are intended in will be described in more detail below.

On the support element 7 or on the support plate 2 can more Power semiconductor 3 may be arranged. As by a comparison of Figs. 4 and 5 to For example, in a brushless DC motor, six can be seen Power semiconductor 3 be located in the control device 1, which is here to MOS-FET acts as a power semiconductor. Furthermore, the carrier element 7 for the Power semiconductor 3 may be formed as a heat sink. The heat sink is approximately vertical arranged projecting from the support plate 2, as shown in FIG. 4 are taken in more detail can. Preferably, the carrier element 7 is pressed into the carrier plate 2 and / or soldered.

Serves a battery, which at a visible in Fig. 1 insertion opening 24 in the Power tool 22 is used to supply power to the electric motor 23, so the carrier plate 2 is arranged in the vicinity of the battery such that the carrier element. 7 with the power semiconductor 3 and / or the power semiconductor 3 itself the battery is facing. For attachable contact of the battery are on the support plate. 2 Plug contacts 11 are arranged. As can be seen from Fig. 3, the Plug contacts 11 in the form of contact clips, for example as "tulip" brackets, educated. The plug contacts 11 are aufsteckund on the carrier plate 2 and / or latched to what an adapter 12 is attached to the plug contact 11.

It lends itself to what can be seen in Fig. 2 in more detail, the support member 7 for the Power semiconductor 3 and / or the power semiconductor 3 directly to the battery facing edge 13 of the support plate 2 to arrange. Conveniently then stand the carrier element 7 and / or the power semiconductor 3 in direct electrical contact to the plug contacts 11 for the battery. The plug contacts 11 may also be integrally in the support plate 2 and / or the support member 7 may be integrated. Furthermore are Capacitors 14 of the control circuit 4 arranged on the support plate 2, and that are the capacitors 14 between the support member 7 for the Power semiconductor 3 and / or the power semiconductor 3 and the plug contacts 11. Alternatively, the capacitors 14 of the control circuit 4 directly on the plug connection 11th be soldered, which is not shown.

To give the user the manual adjustment of the desired speed of the electric motor to allow, located on the support plate 2, a potentiometer 15, as in Fig. 2nd is indicated schematically. Instead of a potentiometer 15 may also be another Sensor element 15, such as a Hall element, a magnetoresistive element o. The like., Used become. With the help of the potentiometer 15 or the sensor element 15 is a setpoint generated, in turn, the control circuit 4 for setting the associated speed for the electric motor 23 is supplied. As can be seen in particular in FIG. 2, this is Potentiometer 15 or the sensor element 15 in a housing 17 of an electric Switch 16 is arranged. An actuator 18 designed in the manner of a pusher is arranged on the housing 17 of the switch 16. With manual movement by the User acts the actuator 18 then on the potentiometer 15 or Sensor element 15 for delivering the corresponding desired value. Next is in the electrical switch 16 again a schematically indicated contact system 19, which also by means of the actuator 18 manually actuated by the user is. The contact system 19 is used to switch the power supply of the electric motor 23. Optionally, by means of the contact system 19 and the power supply of the Control circuit 4 are turned on and off.

In addition, on the support plate 2, yet another electrical switch 20, in which it is in particular a micro and / or snap switch, be arranged. On the further switch 20 acts an actuator 21 for manual operation by the user. The actuator 21 is for example in the manner of a Slider formed and used to switch for the right / left of the Electric motor 23.

As already mentioned, the drive device 1 is preferred for a power tool 22 certainly. The power tool 22 is equipped with a handle shell 25, in which the User holds the power tool 22. It then makes sense to the control device 1 in to arrange the handle shell 25, which can be seen from Fig. 1. This arrangement can be designed such that the actuator 18 and optionally the Actuator 21 for manual operation protrudes from the handle shell 25. 'Alternatively, the control device 1 may be located in the battery, but not is shown further. After inserting the battery into the grip 25 of the power tool 22 then projects the actuator 18 and optionally the actuator 21 from the handle shell 25 out. Just as well when inserting the battery already in the Handle 25 located actuator 18 and optionally the Actuator 21 come in articulation to the control device 1.

The invention is not limited to the described and illustrated embodiments limited. Rather, it also includes all professional training in the context of the inventive concept. Thus, the drive device 1 according to the invention not only find in power tools 22 use, but can also in other Electrical appliances, such as household electrical appliances, electrical gardening equipment, machine tools, Control devices o. The like. Be used advantageously.

Reference numeral list:

1:

Device (for controlling an electric motor) / control device

2: -

support plate

3,3 ':

Power semiconductor

4:

control circuit

5:

Component (the control circuit)

6:

conductor path

7:

support element

8th:

(insulating) coating

9:

metal part

10:

recess

11:

plug contact

12:

Adapter (to plug contact)

13:

Edge (the carrier plate)

14:

capacitor

15:

Sensor element / potentiometer

16:

electrical switch

17:

Housing (from switch)

18:

actuator

19:

Contact system (in the counter)

20:

(further) switch

21:

Actuator (from further switches)

22:

power tool

23:

electric motor

24:

Insertion opening (for battery)

25:

Grip shell (from power tool)

Claims (13)

1. Device for controlling an electric motor (23), in particular a brushless d.c. motor in a battery-operated power tool, comprising at least a power semiconductor (3) for the controllable application of an electric voltage to the electric motor (23), a control circuit (4) for controlling the power semiconductor (3), and comprising a carrier plate (2) configured as a printed circuit board, at least some of the electric and/or electronic components (5) as well as the control circuit (4) comprising the conductor tracks (6) connecting the electric and/or electronic components (5) being arranged on the carrier plate (2), characterised in that the power semiconductor (3) is arranged on a carrier element (7) fastened to the carrier plate (2) and projecting approximately vertically from the carrier plate (2).
2. Device for controlling an electric motor (23) according to claim 1, characterised in that the carrier plate (2) consists of a metal part (9), the surface of which facing the components (5) and the conductor tracks (6) is provided with an insulating coating (8), in such a way that the components (5) and/or the conductor tracks (6) are located for their part on the coating (8), and in that the metal part (9) simultaneously serves as a heat sink.
3. Device for controlling an electric motor (23) according to claim 1 or 2, characterised in that a plurality of power semiconductors (3), in particular a plurality of MOSFETs, for example six MOSFETs, are arranged on the carrier element (7).
4. Device for controlling an electric motor (23) according to any one of claims 1 to 3, characterised in that the carrier element (7) for the power semiconductor (3) is designed as a heat sink, wherein the carrier element (7) is preferably pressed into the carrier plate (2) and/or soldered in.
5. Device for controlling an electric motor (23) according to any one of claims 1 to 4, characterised in that a battery is used for the power supply of the electric motor (23), and in that the carrier plate (2) is arranged near the battery, in particular in such a way that the power semiconductor (3) and/or the carrier element (7) with the power semiconductor (3) faces the battery.
6. Device for controlling an electric motor (23) according to any one of claims 1 to 5, characterised in that plug contacts (11), configured in particular in the manner of contact clamps, for example "tulip" clamps, are arranged on the carrier plate (2) in order to make plug-in contact with the battery, the plug contacts (11) preferably being pluggable and/or latchable onto the carrier plate (2), in particular by means of an adapter (12).
7. Device for controlling an electric motor (23) according to any one of claims 1 to 6, characterised in that the power semiconductor (3) and/or the carrier element (7) for the power semiconductor (3) is arranged directly on the edge (13) of the carrier plate (2) facing the battery, the power semiconductor (3) and/or the carrier element (7) preferably being in direct electric contact with the plug contacts (11) for the battery, the plug contacts (11) more preferably being integrated in one piece into the carrier plate (2) and/or the carrier element (7), and capacitors (14) of the control circuit (4) still more preferably being soldered directly to the plug contact (11).
8. Device for controlling an electric motor (23) according to any one of claims 1 to 7, characterised in that capacitors (14) of the control circuit (4) are arranged on the carrier plate (2), the capacitors (14) in particular being located between the power semiconductor (3) and/or the carrier element (7) for the power semiconductor (3) and the plug contacts (11).
9. Device for controlling an electric motor (23) according to any one of claims 1 to 8, characterised in that a sensor element (15), such as a potentiometer, a Hall element, a magnetoresistive element, is located on the carrier plate (2) to generate a desired value, which is, in turn, fed to the control circuit (4) to adjust an associated rotational speed for the electric motor (23), the sensor element (15) preferably being arranged in a housing (17) of an electric switch (16) and, more preferably, an actuating member (18) for the sensor element (15), designed in particular in the manner of a pushbutton, being arranged on the housing (17) of the switch (16).
10. Device for controlling an electric motor (23) according to any one of claims 1 to 9, characterised in that a contact system (19), which is used, in particular for switching the power supply of the electric motor (23) and optionally of the control circuit (4) is arranged in the electric switch (16), wherein the contact system (19) can preferably be actuated by means of the actuating member (18).
11. Device for controlling an electric motor (23) according to any one of claims 1 to 10, characterised in that a further electric switch (20), in particular a microswitch or a snap-action switch is arranged on the carrier plate (2), an actuating element (21), which is in particular designed in the manner of a slide for switching the electric motor (23) over between clockwise running and counter-clockwise running, acting on the further switch (20).
12. Power tool with a handle shell (25), wherein a device (1) is arranged according to any one of the preceding claims in the handle shell (25) in such a way that the actuating member (18) projects from the handle shell (25) for manual actuation.
13. Power tool with a handle shell (25), wherein a device (1) according to any one of the preceding claims is arranged in the battery in such a way that after insertion of the battery into the handle shell (25) of the power tool (22), the actuating member (18) projects from the handle shell and/or the actuating member (18) already located in the handle shell (25) is articulated on the device (1).

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