Motor

1. A motor comprising a stator, a rotor rotatable relative to the stator, a circuit board fixed to the stator, and a heat sink disposed on the circuit board, a side surface of the circuit board facing the heat sink comprising an insulating region and a metal heat dissipation region without solder mask.

2. The motor according to claim 1 , wherein the material of the insulating region is solder resist ink, and the material of the metal heat dissipation region is nickel gold or tin.

3. The motor according to claim 1 , wherein the circuit board is a two-layer circuit board or a four-layer circuit board, and the circuit board comprises an inverter circuit, and the inverter circuit comprises a plurality of switching transistors, the plurality of switching transistors are mounted on a side surface of the circuit board opposite to the side surface facing the heat sink, and the metal heat dissipation region is under the plurality of switching transistors.

4. The motor according to claim 2 , wherein a heat conducting sheet is disposed between the heat sink and the metal heat dissipation region of the circuit board.

5. The motor according to claim 1 , wherein the circuit board comprises an inverter circuit, the inverter circuit comprising at least two pairs of switching transistors, and each pair of the switching transistors is integrated in one semiconductor package.

6. The motor according to claim 1 , wherein the stator core is fixed to the heat sink via an injection molded member.

7. The motor according to claim 1 , wherein the motor is an outer rotor brushless motor, a bearing of the motor is supported by the heat sink, and the stator and the circuit board are respectively disposed on two sides of the heat sink.

8. A motor comprising a stator, a rotor rotatable relative to the stator, and a circuit board fixed to the stator, the circuit board comprising at least one capacitor and/or an inductor, one end of the at least one capacitor and/or the inductor being mounted to the circuit board, the other end of the capacitor and/or the inductor extending into an interior of the stator so as to overlap windings of the motor in an axial direction.

9. The motor according to claim 8 , wherein the motor comprises a heat sink fixed to the stator, the heat sink has a heat dissipation plate, a bearing housing is formed on the heat dissipation plate, a supporting wall configured for supporting the stator is arranged around the bearing housing, the bearing housing and the supporting wall are partially connected in the circumferential direction through a connecting plate, the radially outer surface of the bearing housing, the radially inner surface of the supporting wall, and the axial inner surface of the connecting plate together form a housing portion with the at least one capacitor and/or the inductor received therein, and the housing portion protrudes into an interior of the stator.

10. A motor comprising a stator, a rotor rotatable relative to the stator, a circuit board fixed to the stator, and a heat sink disposed on the circuit board, a side surface of the circuit board facing the heat sink comprising an insulating region and a metal heat dissipation region without solder mask, wherein at least one capacitor and/or an inductor are mounted on the circuit board, one end of the at least one capacitor and/or the inductor is mounted to the circuit board, the other end of the at least one capacitor and/or the inductor extends into the stator and overlaps with stator windings in an axial direction.

11. The motor according to claim 10 , wherein the heat sink comprises a receiving portion that extends into an interior of the stator, and the at least one capacitor and/or the inductor are received in the receiving portion.