US-12623750-B2 - Drive unit for human-powered vehicle

US12623750B2US 12623750 B2US12623750 B2US 12623750B2US-12623750-B2

Abstract

A drive unit is configured to be provided to a human-powered vehicle. The drive unit basically includes a support, a drive shaft, an output portion, a motor, a transmission mechanism, and a motor output shaft. The drive shaft is configured to receive a human driving force, and includes a first axis. The output portion is provided on the drive shaft. The motor includes a rotor and a stator. The transmission mechanism is configured to transmit a motor torque of the motor to the output portion. The motor output shaft is connected to the rotor, and includes a second axis. The transmission mechanism includes a first transmission unit including a planetary gear mechanism. At least part of the planetary gear mechanism is configured to rotate about the second axis and overlaps the motor as viewed in a first direction that is orthogonal to the second axis.

Inventors

Hiroyuki Ishizaki
Hikaru Naruse
Tsuyoshi Kameda

Assignees

SHIMANO INC.

Dates

Publication Date: 20260512
Application Date: 20250612
Priority Date: 20240826

Claims (20)

1 . A drive unit for a human-powered vehicle, the drive unit comprising: a support; a drive shaft configured to receive a human driving force, and having a first axis; an output portion provided on the drive shaft; a motor including a rotor and a stator; a transmission mechanism configured to transmit a motor torque of the motor to the output portion; and a motor output shaft connected to the rotor, and having a second axis differing from the first axis, the transmission mechanism including a first transmission unit that includes a planetary gear mechanism, at least part of the planetary gear mechanism being configured to rotate about the second axis and overlapping the motor as viewed in a first direction that is orthogonal to the second axis, and the at least part of the planetary gear mechanism overlaps the rotor at a radially outer side of the motor as viewed in the first direction.
2 . The drive unit according to claim 1 , wherein the at least part of the planetary gear mechanism overlaps the rotor as viewed in the first direction.
3 . The drive unit according to claim 1 , wherein the stator is arranged at a radially outer side of the rotor, and the at least part of the planetary gear mechanism is arranged at a radially inner side of the rotor.
4 . The drive unit according to claim 1 , wherein the rotor is arranged at a radially outer side of the stator, and the at least part of the planetary gear mechanism is arranged at a radially inner side of the stator.
5 . The drive unit according to claim 1 , wherein the at least part of the planetary gear mechanism overlaps the rotor at a radially outer side of the motor as viewed in the first direction.
6 . The drive unit according to claim 1 , wherein the transmission mechanism further includes a transmission shaft having a third axis that differs from the first axis and the second axis.
7 . The drive unit according to claim 6 , wherein the transmission mechanism further includes a second transmission unit including a first transmission gear that receives torque from the planetary gear mechanism, and a second transmission gear that is engaged with the first transmission gear and is provided on the transmission shaft.
8 . The drive unit according to claim 7 , wherein the first transmission gear has a first pitch diameter, the second transmission gear has a second pitch diameter, and the second pitch diameter is greater than the first pitch diameter.
9 . The drive unit according to claim 7 , wherein the transmission mechanism further includes a third transmission unit including a third transmission gear that is provided on the transmission shaft, and a fourth transmission gear that is engaged with the third transmission gear and is provided on the output portion.
10 . The drive unit according to claim 9 , wherein the third transmission gear has a third pitch diameter, the fourth transmission gear has a fourth pitch diameter, and the fourth pitch diameter is greater than the third pitch diameter.
11 . The drive unit according to claim 6 , wherein the second axis and the third axis are parallel to the first axis.
12 . The drive unit according to claim 1 , wherein the planetary gear mechanism includes a sun gear configured to receive a rotational torque from the motor output shaft, a ring gear non-rotatably provided on the support, a planet gear configured to receive a rotational torque from the sun gear and is provided between the sun gear and the ring gear, and a carrier supporting the planet gear and configured to output a rotational torque to the output portion.
13 . A drive unit for a human-powered vehicle, the drive unit comprising: a support; a drive shaft configured to receive a human driving force and having a first axis; an output portion provided on the drive shaft; a motor including a rotor and a stator; a transmission mechanism configured to transmit a motor torque of the motor to the output portion; and a motor output shaft connected to the rotor, and having a second axis differing from the first axis, the transmission mechanism including a first transmission unit that includes a planetary gear mechanism, at least part of the planetary gear mechanism being configured to rotate about the second axis and overlapping the motor as viewed in a first direction that is orthogonal to the second axis, and the planetary gear mechanism entirely overlaps the motor as viewed in the first direction.
14 . The drive unit according to claim 1 , wherein: the planetary gear mechanism includes a sun gear, a ring gear, a planet gear provided between the sun gear and the ring gear, and a carrier supporting the planet gear; and at least one of the sun gear, the planet gear, and the ring gear at least partially overlaps the motor as viewed in the first direction.
15 . The drive unit according to claim 14 , wherein at least part of the ring gear overlaps the motor as viewed in the first direction.
16 . The drive unit according to claim 1 , further comprising: a first bearing rotatably supporting the motor output shaft, and at least part of the first bearing overlapping the rotor as viewed in the first direction.
17 . The drive unit according to claim 1 , wherein the motor has a first maximum outer diameter, the output portion has a second maximum outer diameter, and the first maximum diameter is greater than the second maximum diameter.
18 . The drive unit according to claim 1 , further comprising: a circuit board, and the circuit board being arranged at a position separated from the motor output shaft in a second direction that is parallel to the second axis.
19 . A drive unit for a human-powered vehicle, the drive unit comprising: a support; a drive shaft configured to receive a human driving force, and having a first axis; an output portion provided on the drive shaft; a motor including a rotor and a stator; a transmission mechanism configured to transmit a motor torque of the motor to the output portion; a motor output shaft connected to the rotor, and having a second axis differing from the first axis; a circuit board; and a motor rotational state detector configured to detect a rotational state of the motor output shaft, the transmission mechanism including a first transmission unit that includes a planetary gear mechanism, at least part of the planetary gear mechanism being configured to rotate about the second axis and overlapping the motor as viewed in a first direction that is orthogonal to the second axis, the circuit board being arranged at a position separated from the motor output shaft in a second direction that is parallel to the second axis, the circuit board including a predetermined part facing the motor output shaft in the second direction, and the motor rotational state detector being provided on the predetermined part.
20 . The drive unit according to claim 1 , further comprising a human driving force detector configured to detect a human driving force applied to the human-powered vehicle.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to Japanese Patent Application No. 2024-144215, filed on Aug. 26, 2024. The entire disclosure of Japanese Patent Application No. 2024-144215 is hereby incorporated herein by reference. BACKGROUND Technical Field The present disclosure generally relates to a drive unit for a human-powered vehicle. Background Information Japanese Laid-Open Patent Publication No. 2014-196036 (hereinafter referred to as Patent Document 1) discloses an example of a human-powered vehicle drive unit including a motor that applies propulsion force to the human-powered vehicle. In Patent Document 1, torque of the motor is transmitted to a crank axle of the human-powered vehicle. SUMMARY An objective of the present disclosure is to provide a drive unit for a human-powered vehicle that applies propulsion force to the human-powered vehicle in a preferred manner. A drive unit in accordance with a first aspect of the present disclosure is configured for a human-powered vehicle. The drive unit comprises a support, a drive shaft, an output portion, a motor, a transmission mechanism, and a motor output shaft. The drive shaft is configured to receive a human driving force, and has a first axis. The output portion is provided on the drive shaft. The motor includes a rotor and a stator. The transmission mechanism is configured to transmit a motor torque of the motor to the output portion. The motor output shaft is connected to the rotor, and has a second axis differing from the first axis. The transmission mechanism includes a first transmission unit that includes a planetary gear mechanism. At least part of the planetary gear mechanism is configured to rotate about the second axis and overlaps the motor as viewed in a first direction that is orthogonal to the second axis. With the drive unit according to the first aspect, the transmission mechanism transmits motor torque through the first transmission unit, which includes the planetary gear mechanism, to the drive shaft in a preferred manner. Accordingly, the drive unit applies propulsion force to the human-powered vehicle in a preferred manner. With the drive unit according to the first aspect, at least part of the planetary gear mechanism is configured to rotate about the second axis and overlaps the motor as viewed in the first direction that is orthogonal to the second axis. This reduces the drive unit in size in a direction parallel to the first axis. In accordance with a second aspect of the present disclosure, the drive unit according to the first aspect is configured so that the at least part of the planetary gear mechanism overlaps the rotor as viewed in the first direction. With the drive unit according to the second aspect, at least part of the planetary gear mechanism overlaps the rotor as viewed in the first direction. This reduces the drive unit in size in a direction parallel to the first axis. In accordance with a third aspect of the present disclosure, the drive unit according to the second aspect is configured so that the stator is arranged at a radially outer side of the rotor. The at least part of the planetary gear mechanism is arranged at a radially inner side of the rotor. With the drive unit according to the third aspect, at least part of the planetary gear mechanism is arranged at the radially inner side of the rotor. This reduces the drive unit in size in a direction parallel to the first axis. In accordance with a fourth aspect of the present disclosure, the drive unit according to the second aspect is configured so the rotor is arranged at a radially outer side of the stator. The at least part of the planetary gear mechanism is arranged at a radially inner side of the stator. With the drive unit according to the fourth aspect, at least part of the planetary gear mechanism is arranged at the radially inner side of the stator. This reduces the drive unit in size in a direction parallel to the first axis. In accordance with a fifth aspect of the present disclosure, the drive unit according to any one of the first to fourth aspects is configured so that the at least part of the planetary gear mechanism overlaps the rotor at a radially outer side of the motor as viewed in the first direction. With the drive unit according to the fifth aspect, at least part of the planetary gear mechanism overlaps the rotor at the radially outer side of the motor as viewed in the first direction. This reduces the drive unit in size in a direction parallel to the first axis. In accordance with a sixth aspect of the present disclosure, the drive unit according to any one of the first to fifth aspects is configured so that the transmission mechanism further includes a transmission shaft having a third axis that differs from the first axis and the second axis. With the drive unit according to the sixth aspect, at least part of the transmission mechanism is provided on the transmission shaft that differs from the drive s