DE20017779U1 - Brush holder unit for a direct current electric motor with collector - Google Patents

Description

GRÜNECKER KINtfELkEY

8^3CHWANHouse

LAW FIRM

GKS S, S MAXIMIUANSTRASSE 58 D-80S38 MUNICH GERMANY

YOUR SIGN I YOUR REF.

LAWYERS PATENT ATTORNEYS PATENT ATTORNEYS LAWYERS EUROPEAN PATENT ATTORNEYS EUROPEAN PATENT ATTORNEYS MUNICH MUNICH COLOGNE DR. HELMUT EICHMANN DR. HERMANN KINKELDEY DR. MARTIN DROPMANN GERHARD 3ARTH PETER H. JAKOB OR. ULRICH SLUMENRÖOER. LLM. WOLFHARD MEISTER CHEMNITZ CHRISTA NKLAS-FALTER HANS HILGERS MANFRED SCHNEIDER DR, MAXIMILIAN XINKELDEY, LL. M. DR. HENNING MEYER-PLATH SONJA SCHAEFFLER ANNE EHNOLD BERLIN DR. KARSTEN 3RANDT THOMAS SCHUSTER DIETER JANDER ANJA FRANKE, LL.M. DR. KLARA GOLDBACH UTE STEPHAN! MARTIN AUFENANGER DR. BERND ALLEKOTTE. LL. M. GOTTFRIED KLITSCH DR. HEIKE VOGELSANG-WENKE OF COUNSEL REINHARD KNAUER PATENT ATTORNEYS DIETMAR KUHL DR. FRANZ-JOSEF ZIMMER AUGUST GRÜNEECKER BETTINA K. SElCHELT DR. GUNTER BEZOLD DR. ANTON K. PFAU OR. WALTER LANGHOFF DR. UDO WElGELT RAINER BERTRAM JENS KOCH, M.S. (U of PA) M.S. BERND ROTHAEMEL DR. WILFRIED STOCKMAIR DR. DANIELA KINKELDEY (-1996I DR. OUR REF. DATE G4413-035/do 17.10.2000

GATE SPA

Via Andrea Doria 15 1-10123 Torino Italy

Brush holder unit for a DC electric motor with

collector

GRÜNEECKER-KINKELDEY _#

STOCKMAIR &SCHWANHÄUJSEIJ;...* MAXIMILIANSTR. 58 \\',

0-30538 MUNICH "· ···* -

GERMANY

+49 89 21 23 50

# 22*0287··: .·

Mtt>://wwWgrur*!Cker.de· &iacgr;

e-mail: postmaster@grunecker.de

DEUTSCHE BANK MUNICH No. 17 51734 BLZ 700 700 10 SWIFT: DEUT DE MM

"Brush holder unit for a DC electric motor with collector"

The present invention relates to a brush holder assembly for a DC electric motor with a collector, which is used, for example, to drive a radiator fan of a cooling system used in internal combustion engines of motor vehicles.

The control of the rotation speed of such a motor is generally carried out by means of a power circuit comprising electromechanical switches (relays) which are typically located outside the casing or housing of the electric motor. These solutions, which are widely used in practice, have the disadvantage of requiring the preparation and assembly of a suitable housing or housing for these electromechanical switches, as well as the preparation and establishment of the connection with electrical cables between these switches and the motor itself.

The object of the present invention is to realize a brush holder unit with which the disadvantages of the conventional problem solutions of the type described above can be overcome

These and other objects can be achieved according to the invention with a brush holder assembly whose essential characteristics are defined in the appended claim 1.

Further characteristics and advantages of the invention will become apparent from the following detailed description, given as a non-limiting example, with reference to the accompanying drawings, in which:

Figure 1 shows a perspective view of a brush holder assembly according to the invention;

Figure 2 is an electrical diagram showing the connections between the various electrical and electronic components of the brush holder assembly in Figure 1;

Figure 3 is a perspective view showing, partially disassembled, another brush holder assembly according to the invention, and

Figure 4 is an electrical circuit diagram showing a possible embodiment of the connections between the electrical and electronic components of the brush holder unit according to Figure 3.

In Figures 1 and 2, 1 designates a brush holder unit according to the invention.

This assembly comprises a terminal board 2 which is substantially ring-shaped and made of an electrically insulating material, for example fibreglass. The well-known terminal board 2 has a central opening 3 which is suitable for receiving the collector (not shown) of a direct current electric motor.

On one side of the terminal board 2, at diametrically opposite points, two guide boxes 4 and 5 are arranged, on which are mounted, in an axially sliding manner, corresponding conductive brushes 6 and 7. These brushes are pushed towards each other, in a manner known per se, by corresponding elastic devices and are intended to bear against the commutator of the motor.

Electrical conductor tracks are provided on and/or in this terminal board 2, on which electrical and electronic components of a power circuit for controlling the motor are attached and electrically connected. The terminations of the electrically insulated cables 8 (Figure ) for the voltage supply and the application of a control signal in such a circuit will be discussed later.

With reference to Figures 1 and 2, this control circuit comprises a solid state electronic switch Q, advantageously a MOSFET transistor, whose drain is intended to be connected to one of these brushes and whose source is intended to be connected to the negative pole of the direct current voltage source of the power supply (battery) B. The gate of the electronic switch Q is connected through a resistor R1 (Figure 2) to a connection cable 8 intended to enable the application of an electrical control signal to this switch.

Another resistor R2 has been connected between the gate and drain of transistor Q. The anode of a Zener diode Z1 is also connected to the gate and source of transistor Q. Another Zener diode Z2 has its anode connected to the gate of transistor Q and its cathode is connected to the cathode of a diode D whose anode is connected to the drain of transistor Q.

A capacitor C is connected in parallel between the brushes 6 and 7, the former of which is intended, during operation, to be connected to the positive pole of the voltage source of the power supply B.

In the brush carrier unit described above, the power circuit for controlling the motor is advantageously provided "on board" on the same terminal board on which the brushes 6 and 7 are mounted.

This solution avoids the need for a separate installation and assembly of the control circuit, and the usual wiring that had to be prepared using the previous technology to connect the control circuit to the electric motor is no longer necessary.

17· if: &Pgr;&Pgr;

A significant structural simplification is definitely achieved, while the number of components that have to be assembled, mounted and connected to each other has also been reduced.

With reference to Figure 1, the casing or housing of the MOSFET transistor Q connected to the drain is advantageously welded onto a current conductor track 9 provided on the terminal board 2 and which serves simultaneously as a heat sink and an electrical contact, making optimal use of the surface of the circuit board mounted on the terminal board.

Figure 3 shows another embodiment of the brush holder assembly according to the invention. In this figure, which contains components and parts already described, the same numbering as before is used.

In Figure 3, in the brush holder unit 1, four guide boxes 4, 5, 14, 15 are fixed at the same angle equidistant from each other on the terminal board, in which corresponding conductive brushes 6, 7, 16, 17 are slidably mounted, which are intended to rest on the commutator of the electric motor.

On and/or in this terminal board 2, electrical conductor tracks are provided on which electrical and electronic components of a power circuit for controlling the motor, which has, for example, the circuit diagram shown in Figure 4, are attached and electrically connected. According to this circuit diagram, the brushes 6 and 7 are connected to one another and are intended to be connected to the positive pole of the voltage source of the power supply B via an inductor L1. Corresponding control circuits are connected to each of the brushes 16 and 17, which are arranged in such a way and each of which has essentially the same components as already described with reference to the circuit

17-InOO

described in Figure 2. These circuits comprise in particular corresponding solid state electronic switches, in particular MOSFET transistors, designated Q1 and Q2. The sources of these transistors are connected together and are intended to be connected to the negative pole of the voltage source of the power supply B via the inductor L2.

C in Figure 4 indicates a capacitor that is connected in such a way that it operates in parallel with the voltage source.

The control circuit according to Figures 3 and 4 has two control inputs that are connected to the gates of the transistors Q1 and Q2. This control circuit makes it possible to operate the electric motor in the so-called "switched brushes" mode, which enables an operating mode in which two, three or even four brushes are active.

In Figure 3, not all the components of the control circuit are shown in detail in a diagram. However, the two MOSFET transistors Q1 and Q2 are shown. In this embodiment, which is shown as an example, the transistors are physically mounted on the side of the terminal board 2 opposite to that on which the brush guide boxes are mounted. The terminals of these transistors are welded to conductors provided on the underside of the terminal board 2. These transistors are advantageously connected to a solid heat sink such as that indicated at 20 in Figure 3. This heat sink is generally ring-shaped, with two lugs 21 and 22 pointing radially outwards and clamped by springs 30 so as to contact the heat sinks associated with the transistors Q1 and Q2.

The heat sink 20 can be fixed to the terminal board 2 by means of the pegs 23 of this sink, which are inserted during assembly into corresponding openings or holes 24 provided on the terminal board 2.

In the embodiment shown in Figure 3, a multi-pin connector 25 is attached to the underside of the terminal board, which is connected to the power supply terminals and the control signal inputs of the control circuit located on this terminal board.

The brush holder unit described with reference to Figures 3 and 4 also has the same advantages that are made clear in the description of the brush holder unit shown in Figures 1 and 2.

Naturally, while maintaining the principle of the invention, the embodiments and details of implementation may be varied widely from what has been described and illustrated and is intended as a non-limiting example, without however departing from the scope of the invention as defined in the appended claims.

Claims (6)

1. Brush holder assembly ( 1 ) for a direct current electric motor, which is equipped with a collector which
an annular terminal board ( 2 ) on one side of which electrically insulating material is applied, on which at least a first and a second guide box ( 4 , 5 ; 14 , 15 ) are fixed at diametrically opposite points, in which respective conductive brushes ( 6 , 7 ; 16 , 17 ) are slidably mounted, which are intended to bear against the collector, wherein on and/or in this terminal board ( 2 ) tracks made of electrically conductive material are provided, on which electrical and electronic components (Q; Q1, Q2; R1, R2; Z1, Z2, . . . ) of a control circuit of the motor are fixed and electrically connected to one another, the
at least one solid state electronic switch (Q; Q1, Q2) connected to said brushes ( 6 , 7 ; 16 , 17 ) and having an input terminal for a control signal, and
passive components (R1, R2) with bias voltage belonging to this electronic switch (Q; Q1, Q2). 2. Brush holder unit according to claim 1, in which electrically insulating cables ( 8 ) are also connected to the tracks made of electrically conductive material attached to the terminal board ( 2 ), which cables serve to supply voltage and to apply an electrical control signal to the control circuit. 3. Brush holder unit according to claim 1 or 2, in which semiconductor devices (Z2, D3) for protection against overvoltage are also attached and electrically connected to the tracks made of electrically conductive material located on the terminal board ( 2 ). 4. Brush holder unit according to one of the preceding claims, in which the components of the control circuit are arranged on the same side of the terminal board ( 2 ) on which the guide boxes ( 4 , 5 ; 14 , 15 ) for the brushes ( 6 , 7 ; 16 , 17 ) are located. 5. Brush holder unit according to one of the preceding claims, in which at least one electronic switch is a MOSFET transistor (Q; Q1, Q2) which is equipped with a heat sink and which is welded onto a conductor track of the voltage supply ( 9 ) located on the terminal board ( 2 ). 6. Brush holder assembly according to one of the preceding claims from 1 to 3, in which at least one electronic switch is a MOSFET transistor (Q1, Q2) which is attached to the side of the terminal board ( 2 ) opposite the guide boxes ( 4 , 5 ; 14 , 15 ) and has a heat sink which is connected to a dissipating structure ( 20 ) attached to the terminal board ( 2 ) for heat exchange.