Motor power transmission device

Abstract

To provide a power transmission device for a motor that can properly connect or disconnect a wheel hub and the motor.SOLUTION: There is provided a power transmission device for a motor which includes a hub shell 10, a hub shaft 20, a motor, and a power transmission assembly. The power transmission assembly comprises: a transmission wheel which is connected to the motor and is rotated by the driving of the motor; an output plate gear which is coupled to the hub shell 10 in a rotation-driving manner; a bracket which has magnetic attracting force and is arranged between the output plate gear and the motor; a clutch gear which is formed of a magnetic material to be magnetically attracted, and is arranged movably between the bracket and the output plate gear; a press plate which is arranged movably between the bracket and the clutch gear, and is detachably connected to the clutch gear; and an elastic member which is arranged between the bracket and the press plate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power transmission device, and more particularly to a power transmission device for a motor. [Background technology]

[0002] In addition to conventional bicycles that are pedaled entirely by human power, there are also electrically assisted bicycles that help save the user's physical strength. These electrically assisted bicycles assist the bicycle's running by supplying power to the wheels through an electric motor installed on the bicycle. Most of the electric motors installed on electrically assisted bicycles are hub motors that are installed on the bicycle's wheel hub, and the hub motor detects the bicycle's running speed and the user's pedaling state while controlling the rotation speed of the hub motor to provide an appropriate amount of auxiliary power to the wheels.

[0003] However, the maximum speed of an electrically assisted bicycle is regulated by law, so there is an upper limit to the rotation speed of the hub motor. If the bicycle is traveling downhill or the user pedals hard, the power will be cut off when the rotation speed of the hub motor reaches the upper limit. In this state, the hub motor and the bicycle's wheel hub are still connected, so the wheel hub rotates the hub motor instead, and as a result, the hub motor provides extra resistance to the wheel hub, wasting kinetic energy.

[0004] Therefore, how to improve the above-mentioned problems has been a current issue in the industry. Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in consideration of the shortcomings of the conventional technology, and has an object to provide a motor power transmission device that can appropriately connect or disconnect the wheel hub and the motor. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention proposes a motor power transmission device, the motor power transmission device including a hub shell, a hub shaft, a motor, and a power transmission assembly, the hub shaft is installed so as to penetrate both opposing side surfaces of the hub shell, and an extending direction of the hub shaft is defined as a first direction; the motor is connected to the hub shaft and disposed within the hub shell, a rotational drive direction of the motor being defined as a first rotational direction; the power transmission assembly is disposed within the hub shell and connected to the hub shell and a motor, and includes a transmission wheel, an output plate gear, a bracket, a clutch gear, a pressure plate, and an elastic member; The transmission wheel is connected to the motor and rotates in a first rotation direction by being driven by the motor. The transmission wheel has a first annular tooth row on it. the output plate gear is coupled to the hub shell so as to be capable of rotatably driving the hub shell, and the output plate gear has a plurality of first meshing portions formed continuously, the plurality of first meshing portions being formed on a side surface of the output plate gear facing the motor so as to surround a rotation center of the output plate gear, The bracket has a magnetic attraction force and is disposed between the output plate gear and the motor. The bracket has a first pressing surface facing the output plate gear and a first sliding guide portion formed on the first pressing surface. The clutch gear is made of a magnetic material that can be attracted by magnetism, and is disposed between the bracket and the output plate gear so as to be movable along the first direction. The clutch gear has a second annular tooth row, a plurality of second meshing portions formed continuously, and a first engagement portion, the second annular tooth row is connected to mesh with the first annular tooth row, and receives a rotational driving force from the transmission wheel, the plurality of second meshing portions are formed on a side surface of the clutch gear facing the output plate gear, and selectively mesh with the plurality of first meshing portions, and the first engagement portion is formed on a side surface of the clutch gear away from the output plate gear, the pressure plate is disposed between the first pressure surface of the bracket and the clutch gear so as to be movable along the first direction, and is connected to the clutch gear so as to be capable of being brought into contact with and separated from the clutch gear; the pressure plate has a second engagement portion and a second sliding guide portion, and the second engagement portion is formed on a side surface of the pressure plate facing the clutch gear, and can be selectively engaged with the first engagement portion of the clutch gear; when the first engagement portion and the second engagement portion are engaged, the clutch gear rotates the pressure plate; the second sliding guide portion is in slidable contact with the first sliding guide portion of the bracket, and when the second sliding guide portion slides to contact the first sliding guide portion, the pressure plate moves toward the output plate gear; The elastic member applies a biasing force to the bracket and the pressure plate on the side surfaces facing the clutch gear.

[0007] The first and second meshing portions are each a sawtooth ratchet gear capable of meshing with each other.

[0008] Each of the first meshing portions has a first tooth portion and a second tooth portion that are connected to each other, and both the first tooth portion and the second tooth portion are formed to protrude toward the motor and are inclined in a tangential direction of a rotation direction opposite to the first rotation direction.

[0009] The first sliding guide portion has an inclined abutment surface that is inclined toward the pressure plate, and the second sliding guide portion has an abutment protrusion that slidably abuts against the inclined abutment surface.

[0010] The first engagement portion is formed so as to protrude from a side surface of the clutch gear facing the pressure plate, and the second engagement portion is formed so as to protrude from a side surface of the pressure plate facing the clutch gear, and the first engagement portion is engaged so as to abut against the second engagement portion along the first rotational direction.

[0011] The bracket is characterized by including a first magnetic member disposed between the clutch gear and a pressure plate.

[0012] The bracket has a second pressing surface opposing the first pressing surface, and the elastic member is disposed so as to apply a biasing force between the second pressing surface and the pressing plate.

[0013] The first annular tooth row is formed on an outer circumferential surface of the transmission wheel, and the second annular tooth row is formed on an inner circumferential surface of the clutch gear.

[0014] Alternatively, the first annular tooth row is formed on an inner peripheral surface of the transmission wheel, and the second annular tooth row is formed on an outer peripheral surface of the clutch gear.

[0015] The pressure plate is made of a magnetic material that can be magnetically attracted, and the motor power transmission device is characterized in that it includes a second magnetic member that is installed on the bracket and magnetically attracts the pressure plate. Effect of the Invention

[0016] As described above, the advantage of the motor power transmission device according to the present invention is that when the motor stops outputting power, the clutch gear is disconnected from the output plate gear, thereby preventing the motor from causing rotational resistance to the hub shell. On the other hand, when the motor starts outputting driving force, the pressure plate pushes the clutch gear, so that the clutch gear is coupled to mesh with the output plate gear, thereby transmitting the rotational driving force from the motor to the wheels. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a perspective view of a first preferred embodiment of the present invention; [Diagram 2] FIG. 1 is an exploded perspective view of a first preferred embodiment of the present invention. [Diagram 3] FIG. 2 is an exploded perspective view of the first preferred embodiment of the present invention seen from another angle. [Figure 4] FIG. 1 is a perspective view of a power transmission assembly in a first preferred embodiment of the present invention. [Diagram 5] FIG. 1 is a side view of a power transmission assembly in a first preferred embodiment of the present invention. [Figure 6] FIG. 1 is a schematic side sectional view showing an operating state of a power transmission assembly in a first preferred embodiment of the present invention. [Figure 7] FIG. 1 is a schematic side sectional view showing an operating state of a power transmission assembly in a first preferred embodiment of the present invention. [Figure 8] FIG. 1 is a schematic side sectional view showing an operating state of a power transmission assembly in a first preferred embodiment of the present invention. [Figure 9] FIG. 7 is an enlarged view of a local portion of FIG. [Figure 10] FIG. 8 is an enlarged view of a local portion of FIG. [Figure 11] FIG. 9 is an enlarged view of a local portion of FIG. 8. [Figure 12] FIG. 2 is a schematic enlarged view of a local area showing an engagement state between a first engagement portion and a second engagement portion in a first preferred embodiment of the present invention. [Figure 13] FIG. 2 is a side view of a power transmission assembly according to a second preferred embodiment of the present invention, in which a transmission wheel is shown in dashed lines; [Figure 14] FIG. 11 is a plan view showing a power transmission assembly in a second preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] 1 to 4 show a motor power transmission device according to the present invention, and the motor power transmission device includes a hub shell 10, a hub shaft 20, a motor 30, a power transmission assembly 40 and a second magnetic member 50.

[0019] The hub shaft 20 is installed so as to penetrate both opposing side surfaces of the hub shell 10, and the extension direction of the hub shaft 20 is defined as a first direction D1. The motor 30 is connected to the hub shaft 20 and disposed within the hub shell 10, and the rotational drive direction of the motor 30 is defined as a first rotational direction R1.

[0020] 2 to 5 and 12, the power transmission assembly 40 is disposed inside the hub shell 10 so as to be connected to the hub shell 10 and the motor 30. In this preferred embodiment, the hub shaft 20 is installed so as to pass through the power transmission assembly 40, and they are assembled so as to be rotatable relative to each other, however, the method of assembling the hub shaft 20 and the power transmission assembly 40 is not limited to this. The power transmission assembly 40 includes a transmission wheel 41, an output plate gear 42, a bracket 43, a clutch gear 44, a pressure plate 45, and an elastic member 46. These components will be described below.

[0021] The transmission wheel 41 is connected to the motor 30 and rotates in the first rotation direction R1 by being driven by the motor 30. A first annular tooth row 411 is formed on the transmission wheel 41. Specifically, in the first preferred embodiment of the present invention, the first annular tooth row 411 is formed on the outer circumferential surface of the transmission wheel 41, but the formation position of the first annular tooth row 411 is not limited thereto.

[0022] The output plate gear 42 is coupled to the hub shell 10 so as to be able to rotate and drive the hub shell 10. In this preferred embodiment, the hub shell 10 has a coupling recess 11 that corresponds to the outer shape of the output plate gear 42, and the output plate gear 42 is coupled to the hub shell 10 so as to fit into the coupling recess 11, but this is not limited to this, and in other embodiments, the output plate gear 42 may be screwed into the hub shell 10. In addition, the output plate gear 42 has a plurality of first meshing portions 421 formed continuously, and the plurality of first meshing portions 421 are formed on the side of the output plate gear 42 facing the motor 30 so as to surround the center of rotation of the output plate gear 42.

[0023] The first meshing portions 421 will be described in detail. Each of the first meshing portions 421 is a sawtooth ratchet gear, and has a first tooth portion 4211 and a second tooth portion 4212. The first tooth portion 4211 and the second tooth portion 4212 are both formed to protrude toward the motor 30 and are inclined in a tangential direction of a rotation direction opposite to the first rotation direction R1. Specifically, the first meshing portion 421 is formed to protrude from a surface of the output plate gear 42 toward the motor 30, and as shown in FIG. 12, the first tooth portion 4211 and the second tooth portion 4212 are inclined along a tangential direction of a rotation direction opposite to the first rotation direction R1 with respect to the first direction D1.

[0024] The bracket 43 has a magnetic attraction force and is disposed between the output plate gear 42 and the motor 30. The bracket 43 in this preferred embodiment includes a bottom plate portion 431, a support portion 432, and a first magnetic member 433, and the bottom plate portion 431 has a first pressing surface 4311 facing the output plate gear 42, and a first sliding guide portion 4312. Specifically, the first pressing surface 4311 is a side surface of the bottom plate portion 431 of the bracket 43 facing the output plate gear 42, and the first sliding guide portion 4312 is formed on the first pressing surface 4311.

[0025] More specifically, the first sliding guide portion 4312 has an inclined abutment surface 4313 inclined toward the pressing plate 45. Specifically, the inclined abutment surface 4313 is inclined in a direction opposite to the first rotation direction R1 so as to face the pressing plate 45. In this preferred embodiment, the first sliding guide portion 4312 is a recessed groove formed so as to be recessed in the first pressing surface 4311, and the inclined abutment surface 4313 is one side surface of the recessed groove, but in other embodiments, the first sliding guide portion may be a protruding structure formed to protrude from the first pressing surface 4311.

[0026] The support portion 432 is connected to a side surface of the bottom plate portion 431 on the output plate gear 42 side, and is formed to extend so as to surround the clutch gear 44 and the pressing plate 45. The support portion 432 has a second pressing surface 4321. The first magnetic member 433 is installed on the support portion 432, so that the bracket 43 obtains a magnetic attraction force. The second pressing surface 4321 and the first pressing surface 4311 are spaced apart from each other and face each other, and thus a recess is formed between the second pressing surface 4321 and the first pressing surface 4311. Specifically, the second pressing surface 4321 in this preferred embodiment is one of the side surfaces of the support portion 432 facing the first pressing surface 4311.

[0027] The clutch gear 44 is movably disposed between the bracket 43 and the output plate gear 42 along the first direction D1, and is made of a magnetic material that can be attracted by a magnetic force, so that it can be attracted by the magnetic attraction force of the bracket 43. The clutch gear 44 is provided with a second annular tooth row 441, a plurality of second meshing portions 442, and a first engaging portion 443. Specifically, the clutch gear 44 in this preferred embodiment has an inner peripheral surface, and the second annular tooth row 441 is formed on the inner peripheral surface, but is not limited thereto. The second annular tooth row 441 is disposed to mesh with the first annular tooth row 411, and receives a driving force from the transmission wheel 41 and transmits it to the clutch gear 44.

[0028] The second meshing portions 442 are formed continuously on a side surface of the clutch gear 44 facing the output plate gear 42, and each of the second meshing portions 442 is a sawtooth-shaped ratchet gear capable of meshing with each of the first meshing portions 421. The second meshing portions 442 and the first meshing portion 421 can be selectively meshed with each other, and when the first and second meshing portions 421 and 442 mesh with each other, the clutch gear 44 and the output plate gear 42 are joined together. The first engaging portion 443 is formed on a side surface of the clutch gear 44 that is away from the output plate gear 42. Specifically, the first engaging portion 443 is formed so as to protrude from a side surface of the clutch gear 44 facing the pressing plate 45.

[0029] In this preferred embodiment, the pressing plate 45 is preferably made of a magnetic material that can be attracted by magnetism, but is not limited thereto. In other embodiments, the pressing plate may be made of a material that cannot be attracted by magnetism. The pressing plate 45 in this preferred embodiment is disposed between the first pressing surface 4311 of the bracket 43 and the clutch gear 44 so as to be movable along the first direction D1, and is connected to the clutch gear 44 so as to be detachable. Specifically, the pressing plate 45 in this preferred embodiment is disposed in a groove between the first pressing surface 4311 and the second pressing surface 4321 so as to be movable along the first direction D1.

[0030] The pressing plate 45 has a second engaging portion 451 and a second sliding guide portion 452, and the second engaging portion 451 is formed on a side surface of the pressing plate 45 facing the clutch gear 44, and can be selectively locked to the first engaging portion 443. Specifically, the second engaging portion 451 is formed to protrude from a side surface of the pressing plate 45 facing the clutch gear 44, and the first engaging portion 443 can be locked to abut against the second engaging portion 451 along the first rotation direction R1. With this configuration, the clutch gear 44 rotates the pressing plate 45 in the first rotation direction R1 with the first and second engaging portions 443 and 451 locked.

[0031] The second sliding guide portion 452 slidably abuts against the first sliding guide portion 4312 of the bracket 43, and with such a design, when the second sliding guide portion 452 slides to abut against the first sliding guide portion 4312, the pressing plate 45 moves toward the output plate gear 42. Specifically, the second sliding guide portion 452 in this preferred embodiment has an abutment protrusion formed to protrude from a side surface facing the first pressing surface 4311 of the pressing plate 45 and slidably abuts against the inclined abutment surface 4313 of the first sliding guide portion 4312, but is not limited thereto, and in other embodiments, the second sliding guide portion may have an inclined abutment surface, and the first sliding guide portion may be provided with an abutment protrusion.

[0032] The elastic member 46 is disposed between the bracket 43 and the side surface of the pressing plate 45 facing the clutch gear 44. Specifically, the elastic member 46 is a compression coil spring disposed between the second pressing surface 4321 of the bracket 43 and the pressing plate 45, one end side of which contacts the second pressing surface 4321 and the other end side of which biases the pressing plate 45 to press against the first pressing surface 4311.

[0033] The second magnetic member 50 is attached on the bracket 43 and is used to magnetically attract the pressing plate 45. Specifically, the second magnetic member 50 is attached near the first sliding guide portion 4312 on the bottom plate portion 431 of the bracket 43, and this arrangement allows the second magnetic member 50 to generate a magnetic attraction force for the pressing plate 45, but does not allow the second magnetic member 50 to magnetically attract the clutch gear 44. In addition, the bracket 43 in this preferred embodiment is preferably further provided with a positioning ring member 4314 attached to the bottom plate portion 431 for fixing the second magnetic member 50. In addition, in other embodiments, the second magnetic member 50 or the positioning ring member 4314 may not be provided.

[0034] Hereinafter, a method of operating the motor power transmission device according to the present invention will be described with reference to Figures 6 to 12. When the motor 30 is started, the transmission wheel 41 starts to rotate in the first rotation direction R1, and also rotates the clutch gear 44 in the first rotation direction R1. At this time, the clutch gear 44 is located on the pressing plate 45 side due to the magnetic attraction of the first magnetic member 433, and the first engagement portion 443 and the second engagement portion 451 are in a locked state, so that the rotating clutch gear 44 rotates the pressing plate 45 in the first rotation direction R1.

[0035] When the pressing plate 45 rotates, its second sliding guide portion 452 slides along the inclined abutment surface 4313 of the first sliding guide portion 4312, and the pressing plate 45 moves along the first direction D1 toward the output plate gear 42. As a result, the pressing plate 45 presses the clutch gear 44 against the output plate gear 42 along the first direction D1, and meshes the second meshing portion 442 of the clutch gear 44 with the first meshing portion 421 of the output plate gear 42. Furthermore, as shown in FIG. 12, the first tooth portion 4211 and the second tooth portion 4212 are configured to be inclined in a tangential direction of a rotational direction opposite to the first rotational direction R1 with respect to the first direction D1. Therefore, when the clutch gear 44 drives the output plate gear 42 to rotate, if the rotational speed of the clutch gear 44 on the driving side is higher than or equal to the rotational speed of the output plate gear 42 on the driven side, the first meshing portion 421 and the second meshing portion 442 continue to mesh with each other without separating.

[0036] Furthermore, in a state where the second meshing portion 442 and the first meshing portion 421 are engaged with each other, the first tooth portion 4211 and the second tooth portion 4212 are inclined with respect to the first direction D1, so that the clutch gear 44 moves toward the output plate gear 42 along the first direction D1, and as a result, the clutch gear 44 is separated from the pressing plate 45. Then, the pressing plate 45 is pressed against the first pressing surface 4311 of the bracket 43 by the biasing force of the elastic member 46, and at the same time, the second sliding guide portion 452 is returned to the position before the rotational drive by the magnetic attraction force of the second magnetic member 50. Note that the pressing plate 45 does not need to be made entirely of a magnetic material that can be attracted by magnetism, and if the second sliding guide portion 452 is made of a magnetic material that can be attracted by magnetism, it can be returned to the position before the rotational drive by the magnetic attraction action of the second magnetic member 50.

[0037] When the rotational speed of the output plate gear 42 exceeds a predetermined upper limit rotational speed, the motor 30 is turned off, the rotational speed of the clutch gear 44 driven by the motor 30 decreases and becomes lower than the rotational speed of the output plate gear 42. Since the first tooth portion 4211 and the second tooth portion 4212 of the first meshing portion 421 are inclined in the tangential direction of the rotational direction opposite to the first rotational direction R1, at this time, the first meshing portion 421 and the second meshing portion 442 are disengaged from the meshed state, and the clutch gear 44 is pressed toward the motor 30 along the first direction D1, while moving further toward the motor 30 due to the magnetic attraction action of the first magnetic member 433. As a result, the first meshing portion 421 and the second meshing portion 442 are completely separated from each other.

[0038] Figures 13 and 14 show a second preferred embodiment of the present invention. The power transmission device of the motor according to the second preferred embodiment is almost the same as that of the first preferred embodiment, except that in the power transmission assembly 40A, a first annular tooth row 411A of the transmission wheel 41A is formed on the inner peripheral surface of the transmission wheel 41A, and a second annular tooth row 441A of the clutch gear 44A is formed on the outer peripheral surface of the clutch gear 44A.

[0039] As described above, in the motor power transmission device according to the present invention, when the motor 30 is not outputting power, the power transmission relationship between the motor 30 and the hub shell 10 can be separated by the operation of the power transmission assembly 40, and as a result, the hub shell 10 can rotate freely without rotating with the motor 30, making it possible to avoid loss of kinetic energy. Also, when the motor 30 is not outputting power, the bracket 43 according to the present invention separates the clutch gear 44 from the output plate gear 42, making it possible to suppress wear due to continuous contact. Furthermore, when the motor 30 starts, the pressing plate 45 is operated so that the clutch gear 44 is pressed against the output plate gear 42 and coupled thereto, causing the output plate gear 42 to rotate together with it, transmitting the rotational driving force from the motor 30 to the hub shell 10, and then the pressing plate 45 can automatically return to its original position so as not to interfere with the rotation of the clutch gear 44. [Explanation of symbols]

[0040] 10 Hub shell 11 Coupling recess 20 Hub shaft 30 Motor 40, 40A Power Transmission Assembly 41, 41A Transmission wheel 411, 411A First annular dentition 42 Output plate gear 421 First meshing part 4211 1st tooth part 4212 2nd tooth part 43 Bracket 431 Bottom plate part 4311 First pressing surface 4312 First sliding guide 4313 Slanted contact surface 4314 Positioning ring member 432 Support part 4321 Second pressing surface 433 First magnetic member 44, 44A Clutch gear 441, 441A Second annular dentition 442 Second meshing part 443 First engagement part 45 Pressing plate 451 Second engagement part 452 Second sliding guide 46 Elastic Members 50 Second magnetic member D1 1st direction R1 First rotation direction

Claims

1. A motor power transmission device, comprising: a hub shell, a hub shaft, a motor, and a power transmission assembly; the hub shaft is installed so as to penetrate both opposing side surfaces of the hub shell, and an extending direction of the hub shaft is defined as a first direction; the motor is connected to the hub shaft and disposed within the hub shell, a rotational drive direction of the motor being defined as a first rotational direction; the power transmission assembly is disposed within the hub shell and connected to the hub shell and a motor, and includes a transmission wheel, an output plate gear, a bracket, a clutch gear, a pressure plate, and an elastic member; The transmission wheel is connected to the motor and rotates in a first rotation direction by being driven by the motor. The transmission wheel has a first annular tooth row on it. the output plate gear is coupled to the hub shell so as to be capable of rotatably driving the hub shell, and the output plate gear has a plurality of first meshing portions formed continuously, the plurality of first meshing portions being formed on a side surface of the output plate gear facing the motor so as to surround a rotation center of the output plate gear, The bracket has a magnetic attraction force and is disposed between the output plate gear and the motor. The bracket has a first pressing surface facing the output plate gear and a first sliding guide portion formed on the first pressing surface. The clutch gear is made of a magnetic material that can be attracted by magnetism, and is disposed between the bracket and the output plate gear so as to be movable along the first direction. The clutch gear has a second annular tooth row, a plurality of second meshing portions formed continuously, and a first engagement portion, the second annular tooth row is connected to mesh with the first annular tooth row, and receives a rotational driving force from the transmission wheel, the plurality of second meshing portions are formed on a side surface of the clutch gear facing the output plate gear, and selectively mesh with the plurality of first meshing portions, and the first engagement portion is formed on a side surface of the clutch gear facing the pressure plate, the pressure plate is disposed between the first pressure surface of the bracket and the clutch gear so as to be movable along the first direction, and is connected to the clutch gear so as to be capable of being brought into contact with and separated from the clutch gear; the pressure plate has a second engagement portion and a second sliding guide portion, the second engagement portion is formed on a side surface of the pressure plate facing the clutch gear, and can be selectively engaged with the first engagement portion of the clutch gear; when the first engagement portion and the second engagement portion are engaged, the clutch gear rotates the pressure plate; the second sliding guide portion is in slidable contact with the first sliding guide portion of the bracket, and when the second sliding guide portion slides to contact the first sliding guide portion, the pressure plate moves toward the output plate gear; The elastic member biases the pressure plate so as to press the pressure plate against the first pressure surface.

2. 2. The motor power transmission device according to claim 1, wherein each of the first meshing portions and each of the second meshing portions are meshable sawtooth ratchet gears.

3. 3. The motor power transmission device of claim 2, wherein each of the first meshing portions has a first tooth portion and a second tooth portion that are connected to each other, and both the first tooth portion and the second tooth portion are formed to protrude toward the motor and are inclined in a rotational direction opposite to the first rotational direction as they approach the clutch gear along the first direction.

4. The first sliding guide portion has an inclined abutment surface inclined toward the pressing plate, 4. The motor power transmission device according to claim 1, wherein the second sliding guide portion has a contact protrusion that slidably contacts the inclined contact surface.

5. 4. The motor power transmission device according to claim 1, wherein the first engagement portion is formed so as to protrude from a side surface of the clutch gear facing the pressure plate, the second engagement portion is formed so as to protrude from a side surface of the pressure plate facing the clutch gear, and the first engagement portion is engaged so as to abut against the second engagement portion along the first rotational direction.

6. 4. The motor power transmission device according to claim 1, wherein the bracket includes a first magnetic member disposed between the clutch gear and a pressure plate.

7. 4. The motor power transmission device according to claim 1, wherein the bracket has a second pressing surface opposing the first pressing surface, and the elastic member is disposed so as to apply a biasing force between the second pressing surface and the pressing plate.

8. 4. A motor power transmission device according to claim 1, wherein the first annular tooth row is formed on an outer peripheral surface of the transmission wheel, and the second annular tooth row is formed on an inner peripheral surface of the clutch gear.

9. 4. A motor power transmission device according to claim 1, wherein the first annular tooth row is formed on an inner peripheral surface of the transmission wheel, and the second annular tooth row is formed on an outer peripheral surface of the clutch gear.

10. 4. The motor power transmission device according to claim 1, wherein the pressure plate is made of a magnetic material that can be magnetically attracted, and the motor power transmission device includes a second magnetic member that is installed on the bracket and magnetically attracts the pressure plate.

Images