# US 2013/0154448 A1 · Electrical machine for a motor vehicle

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- Number: US 2013/0154448 A1
- Document ID: US20130154448A1
- Status: Published application
- Kind: A1
- Application number: 13/714,080
- Filed: 2012-12-13
- Published: 2013-06-20
- Earliest claimed: 2011-12-14
- Inventors: Matthias Schick
- Web page: https://patentgrep.com/patent/US20130154448A1

## CPC

- H02K 13/00: Structural associations of current collectors with motors or generators, e.g. brush mounting plates or connections to windings (supporting or protecting brushes or brush holders in motor casings or enclosures H02K5/14); Disposition of current collectors in motors or generators; Arrangements for improving commutation
- H01R 39/58: Means structurally associated with the current collector for indicating condition thereof, e.g. for indicating brush wear
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})
- H01R: ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS

## Abstract

An electrical machine, e.g., a starter motor for a motor vehicle, includes at least one carbon brush for producing an electrical sliding contact with a commutator, and a displacement sensor for detecting wear of the carbon brush.

## Claims

### Claim 1

An electrical machine configured as a starter motor for a motor vehicle, comprising:
at least one carbon brush producing an electrical sliding contact with a commutator; and
a displacement sensor detecting wear of the carbon brush.

### Claim 2 (depends on 1)

The electrical machine as recited in claim 1, wherein the displacement sensor is configured to detect a displacement of the carbon brush.

### Claim 3 (depends on 2)

The electrical machine as recited in claim 2, wherein the displacement sensor includes a measuring pin which is in contact with the carbon brush.

### Claim 4 (depends on 3)

The electrical machine as recited in claim 3, wherein the measuring pin includes a carbon-fiber-reinforced plastic.

### Claim 5 (depends on 4)

The electrical machine as recited in claim 4, wherein the measuring pin includes a metallic cladding.

### Claim 6 (depends on 2)

The electrical machine as recited in claim 2, wherein the displacement sensor includes a primary coil and at least one first secondary coil.

### Claim 7 (depends on 6)

The electrical machine as recited in claim 6, wherein the displacement sensor includes an oscillator for converting a DC voltage into an AC voltage.

### Claim 8 (depends on 7)

The electrical machine as recited in claim 7, wherein the oscillator is connected electrically to the primary coil.

### Claim 9 (depends on 7)

The electrical machine as recited in claim 7, wherein the displacement sensor includes a demodulator for filtering an output voltage.

### Claim 10 (depends on 9)

The electrical machine as recited in claim 9, wherein the displacement sensor includes a second secondary coil.

### Claim 11 (depends on 10)

The electrical machine as recited in claim 10, wherein the demodulator is connected electrically to the first and second secondary coils.

### Claim 12 (depends on 11)

The electrical machine as recited in claim 11, wherein the demodulator includes a comparator for comparing voltages induced in the first and second secondary coils.

### Claim 13 (depends on 5)

The electrical machine as recited in claim 5, further comprising:
a motor housing having a feed-through opening through which the measuring pin is inserted.

### Claim 14 (depends on 13)

The electrical machine as recited in claim 13, wherein the motor housing has at least one tapped hole for securing the displacement sensor.

### Claim 15 (depends on 13)

The electrical machine as recited in claim 13, wherein the motor housing has a depression for accommodating the displacement sensor.

### Claim 16 (depends on 13)

The electrical machine as recited in claim 13, wherein the feed-through opening is located directly over the at least one carbon brush.