Battery-powered stand-alone motor unit

Patent metadata

Field	Value
Publication number	US-12289073-B2
Application number	US-202418731781-A
Country	US
Kind code	B2
Filing date	Jun 3, 2024
Priority date	Aug 28, 2018
Publication date	Apr 29, 2025
Grant date	Apr 29, 2025

Abstract

A stand-alone motor unit for use with a piece of power equipment includes a housing and a flange coupled to the housing on a first side thereof. A plurality of apertures through the flange defines a first bolt pattern that matches an identical, second bolt pattern defined in the piece of power equipment. An electric motor has a power output of at least about 2760 W. The motor includes a stator having a nominal outer diameter of up to about 80 mm and a rotor supported for rotation within the stator. A power take-off shaft receives torque from the rotor and protrudes from one of the flange or a second side of the housing. A controller is positioned within the housing and electrically connected to the motor. A battery pack for powering the motor has battery cells having a nominal voltage of up to about 80 V.

First claim

What is claimed is:

1. A stand-alone motor unit for use with a piece of power equipment, the motor unit comprising:
a housing having a first side and a second side adjacent the first side;
a flange coupled to the first side of the housing;
a plurality of apertures through the flange defining a first bolt pattern that matches an identical, second bolt pattern defined in the piece of power equipment;
an electric motor arranged in the housing and including an output shaft;
a battery pack for providing power to the motor;
a power take-off shaft protruding from the second side of the housing; and
a gear train for transferring torque from the output shaft of the motor to the power take-off shaft, the gear train including
a first gear set with a first reduction stage, the first gear set receiving torque from the output shaft of the motor, and
a second gear set with a second reduction stage, the second gear set transferring torque from the first gear set to the power take-off shaft.

2. The stand-alone motor unit of claim 1 , wherein the first gear set includes a first gear coupled for rotation with the output shaft and a second gear coupled for rotation with a second shaft that is parallel with the output shaft.

3. The stand-alone motor unit of claim 2 , wherein the second gear set includes a third gear coupled for rotation with the second shaft and a fourth gear, and wherein the power take-off shaft is coupled for rotation with the fourth gear.

4. The stand-alone motor unit of claim 3 , wherein the first gear is removable from the output shaft, the second and third gears are removable from the second shaft, and the fourth gear is removable from the power take-off shaft.

5. The stand-alone motor unit of claim 4 , further comprising a faceplate that is removably attached to the second side of the housing, such that when the faceplate is removed, the first, second, third, and fourth gears can be removed from the housing.

6. The stand-alone motor unit of claim 3 , wherein the first gear has a first rotational center and the second gear has a second rotational center, such that a first center distance is defied between the first and second rotational centers, and wherein the third gear has a third rotational center and the fourth gear has a fourth rotational center, such that a second center distance is defined between the third and fourth rotational centers.

7. The stand-alone motor unit of claim 6 , wherein the first and second center distances are equal.

8. The stand-alone motor unit of claim 6 , wherein the first center distance is greater than the second center distance.

9. The stand-alone motor unit of claim 6 , wherein the second center distance is greater than the first center distance.

10. The stand-alone motor unit of claim 1 , further comprising a controller configured to
determine whether the stand-alone motor unit is operating in a no-load condition for a pre-determined period of time,
in response to determining that the stand-alone motor unit is operating in the no-load condition, reduce the motor speed of the motor to a no-load speed, and
in response to determining that the stand-alone motor unit is not operating in the no-load condition, operating the motor at a loaded speed that is greater than the no-load speed.

11. The stand-alone motor unit of claim 10 , wherein the controller determines whether the stand-alone motor unit is operating in the no-load condition based on detecting a motor current.

12. The stand-alone motor unit of claim 10 , wherein the controller determines whether the stand-alone motor unit is operating in the no-load condition based on detecting a motor speed.

13. The stand-alone motor unit of claim 10 , wherein the controller determines whether the stand-alone motor unit is operating in the no-load condition for the pre-determined period of time based on determining a point of the stand-alone motor unit on a motor power curve.

14. The stand-alone motor unit of claim 1 , further comprising:
a current sensor and a controller electrically connected to the current sensor, wherein the controller is configured to:
measure, using the current sensor, a motor current,
measure a motor speed,
determine a point on a motor power curve corresponding to the measured motor current and the measured motor speed,
determine whether the stand-alone motor unit is operating in a no-load condition for a pre-determined period of time based on the point on the motor power curve,
in response to determining that the stand-alone motor unit is operating in the no-load condition for a pre-determined period of time, reduce the motor speed of the motor to a no-load speed, and
in response to determining that the stand-alone motor unit is not operating in the no-load condition for a pre-determined period of time, operating the motor at a loaded speed that is greater than the no-load speed.

15. The stand-alone motor unit of claim 1 , further comprising:
a user input device electrically connected to a controller;
a current sensor electrically connected to the controller; and
a power switching network electrically connected between the controller and the motor, wherein the controller is configured to:
control the power switching network to provide power to the motor in response to determining that the user input device has been actuated,
detect, using the current sensor, a current level of the motor,
compare the current level to a bog-down current threshold, and
in response to determining that the current level is greater than the bog-down current threshold, control the power switching network to simulate bog-down.

16. The stand-alone motor unit of claim 15 , wherein simulating bog-down includes at least one selected from the group consisting of
controlling the power switching network to decrease the speed of the motor to a non-zero value, reducing the duty cycle of the power switching network proportional to an amount that the current level is above the bog-down current threshold, and controlling the power switching network to oscillate between different motor speeds.

17. The stand-alone motor unit of claim 15 , after simulating bog-down, the controller is further configured to:
detect a second current level of the motor
compare the second current level to the bog-down current threshold, and
in response to the second current level decreasing below the bog-down current threshold, control the power switching network to cease simulating bog-down and operate the motor in accordance with actuations of the user input device.

18. The stand-alone motor unit of claim 1 , further comprising a transceiver electrically connected to a controller, wherein the controller is configured to:
receive, via the transceiver, a load command from the piece of power equipment,
determine a load limit of the battery pack,
determine whether the load command exceeds the load limit,
in response to determining that the load command does not exceed the load limit, perform normal operation of the stand-alone motor unit,
in response to determining that the load command exceeds the load limit perform limited operation of the stand-alone motor unit.

19. The stand-alone motor unit of claim 18 , wherein normal operation of the stand-alone motor unit includes controlling a power switching network to operate the motor according to the load command.

20. The stand-alone motor unit of claim 18 , wherein limited operation of the stand-alone motor unit includes operating the motor with limited power within the load limi

Assignees

• Milwaukee Electric Tool Corp

Inventors

• Abbott Jonathan E
• Wekwert James
• Hietpas Logan M
• Scott John S
• Thorson Troy C

Classifications

• H01M50/213

  adapted for cells having curved cross-section, e.g. round or elliptic (H01M50/209, H01M50/216 take precedence) · CPC title

• H02K7/116

  with gears · CPC title

• E02D3/046

  by tamping or vibrating, e.g. with auxiliary watering of the soil (E02D3/026, E02D3/08 take precedence; generating or transmitting mechanical vibrations for performing mechanical work in general B06B; tamping or vibrating apparatus for working ballast or railways E01B27/00, for consolidating paving materials E01C19/30, for consolidating concrete in general E04G21/06) · CPC title

• F16H1/20

  involving more than two intermeshing members · CPC title

• H01M2220/20

  Batteries in motive systems, e.g. vehicle, ship, plane · CPC title