Electric work machine

Patent metadata

Field	Value
Publication number	US-12095312-B2
Application number	US-202217824474-A
Country	US
Kind code	B2
Filing date	May 25, 2022
Priority date	Jun 30, 2021
Publication date	Sep 17, 2024
Grant date	Sep 17, 2024

Abstract

A sensor board is downsized. An electric work machine includes a stator, a rotor rotatable about a rotation axis, magnetic sensors, a sensor board supporting the magnetic sensors, and an output unit drivable by the rotor. The stator includes a stator core, an insulator, and coils including first-, second-, and third-phase coils. The rotor includes a rotor core and magnets fixed to the rotor core. The magnetic sensors detect the magnets and include, in a circumferential direction, a first magnetic sensor aligned with at least a portion of a first coil pair, a second magnetic sensor aligned with at least a portion of a second coil pair, and a third magnetic sensor aligned with at least a portion of a third coil pair.

First claim

What is claimed is:

1. An electric work machine, comprising:
a stator ( 30 ) including
a stator core ( 31 ) including a plurality of teeth ( 31 B),
an insulator ( 32 ) fixed to the stator core ( 31 ),
coils ( 33 ) each wound around a corresponding tooth ( 31 B) of the plurality of teeth ( 31 B) with the insulator ( 32 ) in between, the coils ( 33 ) including
a plurality of first-phase coils (C1, C2) assigned to a first phase,
a plurality of second-phase coils (C3, C4) assigned to a second phase, and
a plurality of third-phase coils (C5, C6) assigned to a third phase,
two of the plurality of first-phase coils (C1, C2) adjacent to each other being included in a first coil pair (P 1 a ),
two of the plurality of second-phase coils (C3, C4) adjacent to each other being included in a second coil pair (P 2 a ),
two of the plurality of third-phase coils (C5, C6) adjacent to each other being included in a third coil pair (P 3 a ),
the second coil pair (P 2 a ) being adjacent in a first circumferential direction to the third coil pair (P 3 a ), the first coil pair (P 1 a ) being adjacent in the first circumferential direction to the second coil pair (P 2 a ),
the first coil pair (P 1 a ) including a first-phase coil (C1) located in the first circumferential direction, the first-phase coil (C1) having a winding direction different from a winding direction of a first-phase coil (C2) located in a second circumferential direction in the first coil pair (P 1 a ),
the second coil pair (P 2 a ) including a second-phase coil (C3) located in the first circumferential direction, the second-phase coil (C3) having a winding direction different from a winding direction of a second-phase coil (C4) located in the second circumferential direction in the second coil pair (P 2 a ),
the third coil pair (P 3 a ) including a third-phase coil (C5) located in the first circumferential direction, the third-phase coil (C5) having a winding direction different from a winding direction of a third-phase coil (C6) located in the second circumferential direction in the third coil pair (P 3 a ),
the first coil pair (P 1 a ) and the second coil pair (P 2 a ) adjacent to each other including the first-phase coil (C2) located in the second circumferential direction in the first coil pair (P 1 a ) and the second-phase coil (C3) located in the first circumferential direction in the second coil pair (P 2 a ), the first-phase coil (C2) and the second-phase coil (C3) having a same winding direction,
the second coil pair (P 2 a ) and the third coil pair (P 3 a ) adjacent to each other including the second-phase coil (C4) located in the second circumferential direction in the second coil pair (P 2 a ) and the third-phase coil (C5) located in the first circumferential direction in the third coil pair (P 3 a ), the second-phase coil (C4) and the third-phase coil (C5) having a same winding direction;

a rotor ( 10 ) rotatable about a rotation axis (AX), the rotor ( 10 ) including
a rotor core ( 12 ), and
a plurality of magnets ( 13 ) fixed to the rotor core ( 12 );

a plurality of magnetic sensors ( 51 ) configured to detect the plurality of magnets ( 13 ), the plurality of magnetic sensors ( 51 ) including, in a circumferential direction,
a first magnetic sensor ( 51 U) aligned with at least a portion of the first coil pair (P 1 a ),
a second magnetic sensor ( 51 V) aligned with at least a portion of the second coil pair (P 2 a ), and
a third magnetic sensor ( 51 W) aligned with at least a portion of the third coil pair (P 3 a );

a sensor board ( 50 ) supporting the magnetic sensors ( 51 ); and
an output unit ( 5 ) drivable by the rotor ( 10 ),
wherein
the first magnetic sensor ( 51 U) is between the first-phase coil (C1) located in the first circumferential direction and the first-phase coil (C2) located in the second circumferential direction in the first coil pair (P 1 a ),
the second magnetic sensor ( 51 V) is between the second-phase coil (C3) located in the first circumferential direction and the second-phase coil (C4) located in the second circumferential direction in the second coil pair (P 2 a ), and
the third magnetic sensor ( 51 W) is between the third-phase coil (C5) located in the first circumferential direction and the third-phase coil (C6) located in the second circumferential direction in the third coil pair (P 3 a ).

2. The electric work machine according to claim 1 , wherein
a distance between the first magnetic sensor ( 51 U) and the second magnetic sensor ( 51 V) is equal to a distance between the second magnetic sensor ( 51 V) and the third magnetic sensor ( 51 W) in the circumferential direction.

3. The electric work machine according to claim 2 , wherein
the first coil pair (P 1 a ) includes the two first-phase coils (C1, C2) connected to each other in series, and the two first-phase coils (C1, C2) are first-phase coils formed with a single wire ( 90 ),
the second coil pair (P 2 a ) includes the two second-phase coils (C3, C4) connected to each other in series, and the two second-phase coils (C3, C4) are second-phase coils formed with the single wire ( 90 ), and
the third coil pair (P 3 a ) includes the two third-phase coils (C5, C6) connected to each other in series, and the two third-phase coils (C5, C6) are third-phase coils formed with the single wire ( 90 ).

4. The electric work machine according to claim 2 , further comprising:
a controller ( 100 ) configured to supply a driving current to the plurality of first-phase coils ( 33 ) in response to a detection signal from the first magnetic sensor ( 51 U), to the plurality of second-phase coils ( 33 ) in response to a detection signal from the second magnetic sensor ( 51 V), and to the plurality of third-phase coils ( 33 ) in response to a detection signal the third magnetic sensor ( 51 W).

5. The electric work machine according to claim 1 , wherein
the first coil pair (P 1 a ) includes the two first-phase coils (C1, C2) connected to each other in series, and the two first-phase coils (C1, C2) are first-phase coils formed with a single wire ( 90 ),
the second coil pair (P 2 a ) includes the two second-phase coils (C3, C4) connected to each other in series, and the two second-phase coils (C3, C4) are second-phase coils formed with the single wire ( 90 ), and
the third coil pair (P 3 a ) includes the two third-phase coils (C5, C6) connected to each other in series, and the two third-phase coils (C5, C6) are third-phase coils formed with the single wire ( 90 ).

6. The electric work machine according to claim 1 , further comprising:
a controller ( 100 ) configured to supply a driving current to the plurality of first-phase coils ( 33 ) in response to a detection signal from the first magnetic sensor ( 51 U), to the plurality of second-phase coils ( 33 ) in response to a detection signal from the second magnetic sensor ( 51 V), and to the plurality of third-phase coils ( 33 ) in response to a detection signal the third magnetic sensor ( 51 W).

7. The electric work machine according to claim 1 , wherein
the stator core ( 31 ) includes a yoke ( 31 A) being cylindrical,
the plurality of teeth ( 31 B) protrude radially outward from an outer circumferential surface of the yoke ( 31 A), and
the rotor core ( 12 ) is located outside a periphery of the stator ( 30 ).

8. The electric work machine according to claim 7 , further comprising:
a stator base ( 40 ) supporting the stator ( 30 ),
wherein the sensor board ( 50 ) is supported by the stator base ( 40 ).

9. The electric work machine according to claim 8 , wherein
the sensor board ( 50 ) is in contact with the stator base ( 40 ).

Assignees

• Makita Corp

Inventors

• INUZUKA Junya

Classifications

• H02K3/12

  arranged in slots · CPC title

• H02K7/003

  Couplings; Details of shafts (means for mounting rotors on shafts H02K1/28) · CPC title

• H02K11/30

  Structural association with control circuits or drive circuits · CPC title

• H02K1/16

  Stator cores with slots for windings · CPC title

• H02K11/20

  for measuring, monitoring, testing, protecting or switching (rectifiers H02K11/04; power electronics H02K11/33) · CPC title