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US-12620875-B2 - Battery-powered wheelbarrow

US12620875B2US 12620875 B2US12620875 B2US 12620875B2US-12620875-B2

Abstract

One aspect of the present disclosure provides a battery-powered wheelbarrow including a battery housing, a motor, a wheel, a drive circuit, and a control circuit. The control circuit activates, during a drive requirement of the motor not being satisfied, dynamic braking. The control circuit decreases the dynamic braking through the drive circuit in accordance with a lapse of time in response to a first transition having occurred or occurring.

Inventors

  • Kouichi Takeda

Assignees

  • MAKITA CORPORATION

Dates

Publication Date
20260505
Application Date
20220614
Priority Date
20210616

Claims (20)

  1. 1 . A battery-powered wheelbarrow, comprising: a platform; a handle configured to be gripped by a user of the battery-powered wheelbarrow; a battery housing configured to accommodate a battery therein; a brushless DC motor including a first winding, a second winding, a third winding, a first terminal, a second terminal, and a third terminal, the first winding, the second winding, and the third winding being connected to the first terminal, the second terminal, and the third terminal; a front wheel configured to be driven by the brushless DC motor; a drive circuit configured to: connect the first terminal, the second terminal, and the third terminal to the battery in the battery housing so as to drive the brushless DC motor; and short-circuit at least two of the first terminal, the second terminal, and the third terminal so as to activate a dynamic braking in the brushless DC motor; a control circuit electrically connected to the drive circuit, the control circuit being programmed to: activate the dynamic braking through the drive circuit during (i) a drive requirement of the brushless DC motor not being satisfied, and also (ii) the brushless DC motor being stopped; in response to a first transition having occurred or occurring from the drive requirement not being satisfied to the drive requirement being satisfied, during the brushless DC motor being stopped, decrease the dynamic braking through the drive circuit in accordance with a lapse of time, in response to a rotational speed of the brushless DC motor having stayed at a threshold or lower for a preset period of time after the first transition occurs, drive the brushless DC motor; and in response to a second transition having occurred or occurring, from the drive requirement being satisfied to the drive requirement not being satisfied, during the brushless DC motor rotating, increase the dynamic braking through the drive circuit in accordance with a lapse of time; and a manual switch configured (i) to be manually operated by the user and (ii) to output a first signal to the control circuit in response to the manual switch having been manually operated or being manually operated, the first signal requesting the control circuit to drive the brushless DC motor, wherein the drive requirement is satisfied with the manual switch having been manually operated or being manually operated.
  2. 2 . A battery-powered wheelbarrow, comprising: a battery housing configured to accommodate a battery therein; a motor including two or more windings and two or more terminals, the two or more windings being connected to the two or more terminals; a wheel configured to be driven by the motor; a drive circuit configured to: connect the two or more terminals to the battery in the battery housing so as to drive the motor; and short-circuit at least two of the two or more terminals so as to activate a dynamic braking in the motor; a control circuit configured to: activate the dynamic braking through the drive circuit during a drive requirement of the motor not being satisfied, and in response to a first transition having occurred or occurring from the drive requirement not being satisfied to the drive requirement being satisfied, decrease the dynamic braking through the drive circuit in accordance with a lapse of time; and a first manual switch configured (i) to be manually operated by a user of the battery-powered wheelbarrow and (ii) to output a first signal to the control circuit in response to the first manual switch having been manually operated or being manually operated, the first signal requesting the control circuit to drive the motor, wherein the drive requirement is satisfied with the first manual switch having been manually operated or being manually operated.
  3. 3 . The battery-powered wheelbarrow according to claim 2 , wherein the control circuit is further configured to deactivate the dynamic braking through the drive circuit in response to (i) a first additional requirement being satisfied, and also (ii) the first transition having occurred or occurring.
  4. 4 . The battery-powered wheelbarrow according to claim 3 , wherein the first additional requirement is satisfied with a rotational speed of the motor reaching a first threshold.
  5. 5 . The battery-powered wheelbarrow according to claim 3 , wherein the control circuit is configured to, in response to a second transition having occurred or occurring from the drive requirement being satisfied to the drive requirement not being satisfied, during the motor rotating, increase the dynamic braking through the drive circuit in accordance with a lapse of time.
  6. 6 . The battery-powered wheelbarrow according to claim 5 , wherein the first additional requirement is satisfied with (i) the rotational speed of the motor reaching the first threshold, and also (ii) a magnitude of the dynamic braking being smaller than a preset magnitude.
  7. 7 . The battery-powered wheelbarrow according to claim 2 , wherein the control circuit is further configured to deactivate the dynamic braking through the drive circuit, in response to a second additional requirement being satisfied after the first transition occurs.
  8. 8 . The battery-powered wheelbarrow according to claim 7 , wherein the second additional requirement is satisfied with a third additional requirement being satisfied, and wherein the third additional requirement is satisfied with the rotational speed of the motor having stayed at a second threshold speed or lower for a first preset period of time from a first time point, the first time point arriving after the first transition occurs.
  9. 9 . The battery-powered wheelbarrow according to claim 8 , wherein the second threshold corresponds to the rotational speed of zero.
  10. 10 . The battery-powered wheelbarrow according to claim 8 , wherein the second additional requirement is satisfied with the third additional requirement being satisfied after a fourth additional requirement is satisfied, wherein the fourth additional requirement is satisfied with a second preset period of time elapsing from a second time point after the first transition occurs, and wherein the first time point is a time point after the fourth additional requirement is satisfied.
  11. 11 . The battery-powered wheelbarrow according to claim 7 , wherein the control circuit is further configured to: specify a rotational direction of the motor, and control the motor via the drive circuit such that the motor rotates in the rotational direction specified, wherein the second additional requirement is satisfied with a fifth additional requirement being satisfied, and wherein the fifth additional requirement is satisfied with the motor rotating in a direction opposite to the rotational direction specified.
  12. 12 . The battery-powered wheelbarrow according to claim 11 , wherein the second additional requirement is satisfied with the fifth additional requirement being satisfied after a fourth additional requirement is satisfied, and wherein the fourth additional requirement is satisfied with a second preset period of time elapsing from a second time point after the first transition occurs.
  13. 13 . The battery-powered wheelbarrow according to claim 2 , further comprising: a second manual switch configured to be manually operated by the user; and a mechanical brake configured to directly brake rotation of the wheel in response to the second manual switch being manually operated, wherein the drive requirement is satisfied with (i) the first manual switch having been manually operated or being manually operated, and also (ii) the mechanical brake being deactivated.
  14. 14 . The battery-powered wheelbarrow according to claim 2 , further comprising: an electromagnetic brake (i) including an electromagnet, and also (ii) configured to generate a magnetic force via the electromagnet to thereby brake the motor or to release the motor from braking.
  15. 15 . The battery-powered wheelbarrow according to claim 14 , wherein the control circuit is further configured to activate the electromagnetic brake during (i) the drive requirement not being satisfied, and also (ii) the rotational speed of the motor being a third threshold or lower.
  16. 16 . The battery-powered wheelbarrow according to claim 14 , wherein the control circuit is further configured to deactivate the electromagnetic brake in response to the first transition having occurred or occurring.
  17. 17 . The battery-powered wheelbarrow according to claim 2 , wherein the two or more terminals include a first terminal, a second terminal, and a third terminal, wherein the drive circuit is configured to deliver a three-phase electric power to the first terminal, the second terminal, and the third terminal, and wherein the control circuit is configured to, during the motor being stopped, short-circuit the first terminal, the second terminal, and the third terminal to each other.
  18. 18 . The battery-powered wheelbarrow according to claim 2 , wherein the two or more terminals include a first terminal, a second terminal, and a third terminal, wherein the drive circuit is configured to deliver a three-phase electric power to the first terminal, the second terminal, and the third terminal, and wherein the control circuit is configured to, during the motor rotating, (i) short-circuit two terminals of the first terminal, the second terminal, and the third terminal to each other, and/or (ii) short-circuit the first terminal, the second terminal, and the third terminal to each other.
  19. 19 . The battery-powered wheelbarrow according to claim 2 , further comprising: an electromagnetic brake (i) including an electromagnet, and also (ii) configured to generate a magnetic force via the electromagnet to thereby brake the motor or to release the motor from braking, wherein the control circuit is configured to: during the drive requirement not being satisfied and also the motor being stopped, activate the dynamic braking through the drive circuit and also activate the electromagnetic brake; and in response to the first transition having occurred or occurring during the motor being stopped, (i) deactivate the electromagnetic brake in advance of the dynamic braking and also (ii) decrease the dynamic braking through the drive circuit in accordance with a lapse of time.
  20. 20 . A method of controlling a dynamic braking in a battery-powered wheelbarrow, the method comprising: during a drive requirement of a motor of the battery-powered wheelbarrow being not satisfied, activating the dynamic braking of the motor to thereby inhibit the battery-powered wheelbarrow from moving, the drive requirement being satisfied with a manual switch having been manually operated or being manually operated, the manual switch being configured to request the battery-powered wheelbarrow to drive the motor in response to the manual switch having been manually operated or being manually operated; and in response to the drive requirement being satisfied, decreasing the dynamic braking in accordance with a lapse of time to thereby allow the battery-powered wheelbarrow to move.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present disclosure claims the benefit of Japanese Patent Application No. 2021-100461 filed on Jun. 16, 2021 with the Japan Patent Office, the entire disclosure of which is incorporated herein by reference. BACKGROUND The present disclosure relates to a battery-powered wheelbarrow. Japanese Unexamined Patent Application Publication No. 2019-022338 discloses a battery-powered wheelbarrow with motor-driven wheels. This wheelbarrow includes a mechanical brake device. The mechanical brake device directly applies a braking force to a wheel of the wheelbarrow using a friction force. Further, the wheel harrow includes dynamic braking. The dynamic braking generates the braking force in the motor by short-circuiting motor windings. SUMMARY The mechanical brake is manually adjustable by a user of the wheelbarrow, whereas the dynamic braking is controlled by a microcomputer in the wheelbarrow. In order to allow the user to stably use such battery-powered wheelbarrow, it is desired to properly control the dynamic braking. In one aspect of the present disclosure, if is desirable that dynamic braking in a battery-powered wheelbarrow can be properly controlled. One aspect of the present disclosure provides a battery-powered wheelbarrow (or a battery-powered dolly) including a battery housing. The battery housing accommodates a battery therein. The battery-powered wheelbarrow includes a motor. The motor includes two or more windings and two or more terminals. The two or more windings are connected to the two or more terminals. The battery-powered wheelbarrow includes a wheel driven by the motor. The battery-powered wheelbarrow includes a drive circuit. The drive circuit connects the two or more terminals to the battery in the battery housing so as to drive the motor. The drive circuit short-circuits at least two of the two or more terminals so as to activate a dynamic braking in the motor. The battery-powered wheelbarrow includes a control circuit. The control circuit activates the dynamic braking through the drive circuit during a drive requirement of the motor not being satisfied. The control circuit decreases the dynamic braking (or a braking force by the dynamic braking) through the drive circuit in accordance with a lapse of time (gradually, continuously, or stepwisely) in response to a first transition having occurred or occurring from the drive requirement not being satisfied to the drive requirement being satisfied. The battery-powered wheelbarrow described above can control the dynamic braking properly. In another aspect of the present disclosure, a method of controlling a dynamic braking is used in a battery-powered wheelbarrow. The method includes activating the dynamic braking to thereby inhibit the battery-powered wheelbarrow from moving. The method includes decrasing the dynamic braking in accordance with a lapse of time to thereby allow the battery-powered wheelbarrow to move. The method can exert advantageous effects similar to the aforementioned battery-powered wheel barrow. BRIEF DESCRIPTION OF THE DRAWINGS An example embodiment of the present disclosure will be described hereinafter by way of example with reference to the accompanying drawings, in which: FIG. 1 is a perspective view of a battery-powered wheelbarrow according to an embodiment; FIG. 2 is a bottom view of the battery-powered wheelbarrow without a platform; FIG. 3 is a sectional view taking along line III-III in FIG. 2; FIG. 4 is a block diagram illustrating a configuration of an electric system of the battery-powered wheelbarrow; FIG. 5A is a block diagram of an electric system of a manipulation device in more detail; FIG. 5B is a block diagram of an electric system and the like of a battery box in more detail; FIG. 6 is a flowchart of a main process; FIG. 7 is a flowchart of one part of a control mode setting process; FIG. 8 is a flowchart of another part of the control mode setting process; FIG. 9 is a flowchart of a first deactivating determination process; FIG. 10 is a flowchart of still another of the control mode setting process; FIG. 11A is a flowchart of a second deactivating determination process; FIG. 11B is a flowchart of a braking-start determination process; FIG. 12 is a flowchart of an electromagnetic brake control process; FIG. 13 is a flowchart of a motor control process; FIG. 14 is a flowchart of a motor output control process; FIG. 15 is a flowchart of a standby braking process; FIG. 16 is a flowchart of a first braking process; FIG. 17 is a flowchart of a second braking process. DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS Overview of Embodiment A battery-powered wheelbarrow according to an embodiment may include a handle. The handle may be configured to be gripped by a user of the battery-powered wheelbarrow. The user may use the battery-powered wheelbarrow while standing on a ground where the battery-powered wheelbarrow travels. The user may use the battery-powered wheelbarrow w