Rotary drive device

Abstract

The present application provides a rotary drive device capable of reducing the space required for installation in a mobile body main body. A rotary drive device (DV) provided in a mobile body has a main wheel (5) and a pair of drive portions (DP). The pair of drive portions oppose each other in an axial direction (AD) and each drive the main wheel. The main wheel has a plurality of driven rollers (51). A drive portion (DA) of the pair of drive portions has a motor (17), a motor case (18), a drive force transmission member, and a plurality of drive rollers (120). The plurality of drive rollers are disposed in the drive force transmission member in a circumferential direction (CD) and contact at least a portion of the plurality of driven rollers from one side in the axial direction. The drive force transmission member rotates and transmits the drive force of the motor to the main wheel via the plurality of drive rollers (120). At least a portion (80) of the motor case opposes at least a portion of the plurality of drive rollers in the axial direction and is capable of being installed in a mobile body main body (3) of the mobile body.

Description

Technical Field

[0001] The present invention relates to a rotary drive device. Background Art

[0002] Conventional friction drive devices are incorporated into an inverted vibrator-type mobile body as a travel unit (e.g., Patent Document 1). The inverted vibrator-type mobile body includes a lower frame and an upper frame connected to each other. The friction drive device is supported by the lower frame of the inverted vibrator-type mobile body. The lower frame includes a left side wall and a right side wall that are spaced apart and opposed to each other in the left-right direction.

[0003] The friction drive device includes left and right cylindrical mounting members. The friction drive device is positioned between the left and right side walls of the lower frame. The left and right mounting members are secured to the inner sides of the left and right side walls, respectively, using mounting bolts. Specifically, the left and right mounting members are secured to the lower frame concentrically with respect to the central axis.

[0004] The left and right mounting members each rotatably support left and right annular drive plates on the outer periphery of the mounting member's cylindrical portion via cross roller bearings. Each drive plate has an outer annular portion with a larger diameter than the cylindrical portion of the drive plate. The left and right drive rollers are rotatably mounted to the outer annular portion via roller shafts.

[0005] Left and right electric motors are positioned inside the cylindrical portions of the left and right drive plates. The output rotation of the left and right electric motors is reduced by left and right planetary gear mechanisms and transmitted to the left and right drive plates, respectively. The left and right planetary gear mechanisms have sun gears as input components fixed to the rotor shafts of the left and right electric motors, ring gears as output components fixed to the left and right drive plates, and pinion carriers as reaction force components fixed to mounting members, forming a reduction gear. The outer housings of the left and right electric motors, which house stator coils and other components, are secured to the left and right mounting members with bolts.

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2011-63209

[0007] However, conventional friction-type drive devices use left and right mounting components that are fixedly mounted on the left and right side walls of the lower frame of the inverted vibrator-type mobile body, respectively. Therefore, in addition to the space required to configure the left and right mounting components, extra space may sometimes be generated between the inner circumferential surface of the cylindrical portion of the mounting component and the outer housing of the electric motor. In addition, when an electric motor of a size that is not accommodated inside the cylindrical portion of the drive disk is mounted, a mounting component of a larger size is required, so the distance between the mounting position toward the left side wall and the mounting position toward the right side wall, that is, the distance between the left end of the left mounting component and the right end of the right mounting component, may be further increased. As a result, extra space may be required to mount the friction-type drive device on the lower frame of the inverted vibrator-type mobile body. Summary of the Invention

[0008] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a rotation drive device capable of reducing the space required for installation on a mobile body.

[0009] A rotary drive device according to an example of the present invention is configured for a mobile object. The rotary drive device includes a main wheel and a pair of drive units. The main wheel is rotatable about a rotation axis. The pair of drive units are opposed to each other in an axial direction along the rotation axis and respectively drive the main wheel. The main wheel includes a plurality of driven rollers arranged circumferentially relative to the rotation axis. The first drive unit, serving as one of the pair of drive units, includes a first motor, a first motor housing, a first driving force transmission component, and a plurality of first driving rollers. The first motor housing houses the first motor. The first driving force transmission component rotates about the rotation axis. The plurality of first driving rollers are arranged circumferentially relative to the first driving force transmission component and contact at least a portion of the plurality of driven rollers from one side in the axial direction. The first driving force transmission component rotates to transmit the driving force of the first motor to the main wheel via the plurality of first driving rollers. At least a portion of the first motor housing is opposed to at least a portion of the plurality of first driving rollers in the axial direction. The at least a portion of the first motor housing can be mounted to the main body of the mobile object.

[0010] According to the illustrated embodiment of the present invention, it is possible to provide a rotation drive device capable of reducing the space required for installation in a mobile body. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a perspective view showing a transport vehicle according to an embodiment of the present invention.

[0012] Figure 2 It is a side view showing the transport vehicle of this embodiment.

[0013] Figure 3It is a bottom view showing the transport vehicle according to this embodiment.

[0014] Figure 4 It is a perspective view showing the rotation drive device of the transport vehicle according to this embodiment.

[0015] Figure 5 It is a perspective view showing a driving portion of the rotation driving device according to the present embodiment.

[0016] Figure 6A This is a perspective view showing a driving roller of the driving force transmission device according to the present embodiment.

[0017] Figure 6B This is a plan view showing a driving roller of the driving force transmission device according to the present embodiment.

[0018] Figure 7A It is a perspective view showing a rotation drive device and a portion of a vehicle body of a transport vehicle according to this embodiment.

[0019] Figure 7B It is a perspective view showing a rotation drive device and a portion of a vehicle body of a transport vehicle according to this embodiment.

[0020] Figure 8A It is a perspective view showing a motor case of the rotation drive device according to the present embodiment.

[0021] Figure 8B It is a cross-sectional view showing a motor case of the rotation drive device according to the present embodiment.

[0022] Figure 9 It is an exploded perspective view showing the motor unit and the front bracket of the rotation drive device according to the present embodiment.

[0023] Figure 10 It is along Figure 4 Cross-sectional view of line XX.

[0024] Figure 11 It is along Figure 4 Cross-sectional view along line XI-XI.

[0025] Figure 12 It is a side view showing a rotation drive device according to a modified example of the present embodiment.

[0026] Figure 13 It is along Figure 12 A cross-sectional view taken along line XIII-XIII.

[0027] Figure 14 It is a cross-sectional view showing a rotation drive device according to a modified example of the present embodiment.

[0028] Label Description

[0029] 1: Truck (mobile body); 3: Vehicle body (mobile body main body); 5: Main wheel; 51: Driven roller; AD: Axial direction; AX: Rotation axis; CD: Circumferential direction; DA: First drive unit; DB: Second drive unit; DP: A pair of drive units; DV: Rotational drive device; 110, 110A: First driving force transmission component; 110, 110B: Second driving force transmission component; 120, 120A: First driving roller; 120, 120B: Second driving roller; 17, 17A: First motor; 17, 17B: Second motor; 18, 18A: First motor housing; 18, 18B: Second motor housing; 80, 80A: A specific part (at least a part of the first motor housing); 80, 80B: A specific part (at least a part of the second motor housing). DETAILED DESCRIPTION

[0030] Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, identical or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated. Furthermore, in the drawings, the X-axis, Y-axis, and Z-axis of a three-dimensional orthogonal coordinate system are appropriately indicated for ease of understanding.

[0031] In this specification, the rotation axis AX (eg Figure 3 ) is recorded as "axial direction AD". That is, the direction along the axis of rotation is recorded as "axial direction AD". In addition, the direction perpendicular to the axis of rotation AX is recorded as "radial direction RD". "Radial direction RD" is equivalent to an example of "radial direction relative to the axis of rotation". In addition, the direction along the arc centered on the axis of rotation AX is recorded as "circumferential direction CD". "Circumferential direction CD" is equivalent to an example of "circumferential direction around the axis of rotation". In addition, "parallel direction" includes substantially parallel directions, and "perpendicular direction" includes substantially perpendicular directions. In addition, "left and right" means left and right when observing the object from the radial direction RD.

[0032] Reference Figures 1 to 14 The transport vehicle 1, the rotary drive device DV, the first driving force transmission device 11A, the second driving force transmission device 11B, the first driving force transmission member 110A, and the second driving force transmission member 110B according to the embodiment of the present invention will be described. Figures 1 to 3 The transport vehicle 1 will be described.

[0033] Figure 1 It is a perspective view showing the transport vehicle 1 . Figure 2 It is a side view showing the transport vehicle 1 . Figure 3 FIG. 1 is a bottom view showing the transport vehicle 1. Figure 3 In the figure, the transport vehicle 1 is viewed from the side of the floor or the ground.

[0034] Figure 1 and Figure 2 The transport vehicle 1 shown in the figure travels on a floor or ground. In this embodiment, the transport vehicle 1 is an automated guided vehicle (AGV). The transport vehicle 1 is an example of a "moving object."

[0035] like Figure 1 As shown in FIG, the transport vehicle 1 has a vehicle body 3. In other words, the vehicle body 3 is arranged on the transport vehicle 1. Figure 1 and Figure 2 In the example shown in FIG. 3 , the vehicle body 3 has a substantially rectangular parallelepiped shape. However, the shape of the vehicle body 3 is not particularly limited. The vehicle body 3 is an example of a “mobile body main body”.

[0036] like Figure 2 and Figure 3 As shown, the transport vehicle 1 further includes multiple rotation drive devices DV and multiple wheels 7. In this embodiment, the transport vehicle 1 includes a pair of rotation drive devices DV and four wheels 7. The four wheels 7 are respectively arranged at the four corners of the bottom 3a of the vehicle body 3. Each wheel 7 rotates as the vehicle body 3 moves. The pair of rotation drive devices DV rotates independently of each other to move the vehicle body 3. The pair of rotation drive devices DV are arranged on the bottom 3a of the vehicle body 3 so that the rotation axis AX of one of the pair of rotation drive devices DV is aligned with the rotation axis AX of the other rotation drive device DV.

[0037] The pair of rotation drive devices DV have the same structure. Therefore, the following description will focus on one of the pair of rotation drive devices DV.

[0038] like Figure 3 As shown, the rotation drive device DV includes a main wheel 5 and a pair of drive units DP. The pair of drive units DP oppose each other in the axial direction AD along the rotation axis AX and each drive the main wheel 5. One of the pair of drive units DP is the first drive unit DA. The other of the pair of drive units DP is the second drive unit DB. In other words, the rotation drive device DV includes the main wheel 5, the first drive unit DA, and the second drive unit DB. The main wheel 5 is rotatable about the rotation axis AX. Specifically, the first drive unit DA and the second drive unit DB drive the main wheel 5. As a result, the main wheel 5 rotates about the rotation axis AX. Therefore, the rotation axis AX also serves as the rotation axis of the main wheel 5. The first drive unit DA drives the main wheel 5 by contacting the main wheel 5 from one side of the main wheel 5 in the axial direction AD. The second drive unit DB drives the main wheel 5 by contacting the main wheel 5 from the other side of the main wheel 5 in the axial direction AD.

[0039] The first drive unit DA includes a first driving force transmission device 11A, a first motor 17A, and a first motor housing 18A. The first motor 17A includes a first rotating shaft 171A. The first motor housing 18A houses the first motor 17A. At least a portion 80A of the first motor housing 18A can be mounted on the vehicle body 3. The first rotating shaft 171A is an example of an "output shaft of the first motor."

[0040] The second drive unit DB includes a second driving force transmission device 11B, a second motor 17B, and a second motor housing 18B. The second motor 17B includes a second rotating shaft 171B. The second motor housing 18B houses the second motor 17B. At least a portion 80B of the second motor housing 18B can be mounted on the vehicle body 3. The second rotating shaft 171B is an example of an "output shaft of the second motor." The structures of the second motor 17B and the second motor housing 18B are identical to those of the first motor 17A and the first motor housing 18A of the first drive unit DA, respectively, and their descriptions are omitted. The second driving force transmission device 11B is a left-right inverted version of the first driving force transmission device 11A of the first drive unit DA, and its description is omitted as appropriate. Hereinafter, the "first driving force transmission device 11A" and the "second driving force transmission device 11B" may be collectively referred to as the "driving force transmission device 11." Hereinafter, the "first motor 17A" and the "second motor 17B" may be collectively referred to as the "motor 17." In the following, the "first rotating shaft 171A" and the "second rotating shaft 171B" may be collectively referred to as "rotating shaft 171." In the following, the "first motor housing 18A" and the "second motor housing 18B" may be collectively referred to as "motor housing 18." In the following, the "at least a portion 80A of the first motor housing 18A" and the "at least a portion 80B of the second motor housing 18B" may be collectively referred to as "at least a portion 80 of the motor housing 18." For convenience, the "at least a portion 80 of the motor housing 18," the "at least a portion 80A of the first motor housing 18A," and the "at least a portion 80B of the second motor housing 18B" may be referred to as "the specific portion 80," the "specific portion 80A," and the "specific portion 80B," respectively.

[0041] Next, refer to Figure 4 The rotation drive device DV will be described. Figure 4 : is a perspective view showing the rotation drive device DV. Figure 4As shown, in the rotary drive device DV, the first driving force transmission device 11A of the first driving unit DA has a generally disc shape. The first driving force transmission device 11A is arranged on one side of the main wheel 5 in the axial direction AD. The first driving force transmission device 11A is supported so as to be rotatable. The first driving force transmission device 11A is driven by the first motor 17A to rotate about the rotation axis AX. Therefore, the rotation axis AX is also the rotation axis of the first driving force transmission device 11A. Furthermore, the first driving force transmission device 11A contacts the main wheel 5 from the side of the main wheel 5 in the axial direction AD to drive the main wheel 5.

[0042] The first driving force transmission device 11A rotates about the rotation axis AX. As a result, the first driving force transmission device 11A transmits driving force based on the rotational force to the main wheels 5. In other words, the first driving force transmission device 11A transmits driving force from the first motor 17A to the main wheels 5.

[0043] Furthermore, the second driving force transmission device 11B of the second drive unit DB has a generally disc shape. The second driving force transmission device 11B is disposed on the other side of the main wheel 5 in the axial direction AD. The second driving force transmission device 11B is rotatably supported by the main shaft 9. The second driving force transmission device 11B is driven by the second motor 17B to rotate about the rotation axis AX. Therefore, the rotation axis AX also serves as the rotation axis of the second driving force transmission device 11B. Furthermore, the second driving force transmission device 11B contacts the main wheel 5 from the other side of the main wheel 5 in the axial direction AD, thereby driving the main wheel 5.

[0044] The first driving force transmission device 11A and the second driving force transmission device 11B sandwich the main wheel 5 in the axial direction AD. Furthermore, the first driving force transmission device 11A and the second driving force transmission device 11B are arranged bilaterally symmetrically with the main wheel 5 interposed therebetween. Furthermore, the first driving force transmission device 11A and the second driving force transmission device 11B support the main wheel 5 so that it can rotate about the rotation axis AX.

[0045] The main wheel 5 has a plurality of driven rollers 51 and a core 53. The core 53 extends along the circumferential direction CD around the rotation axis AX. The core 53 has a roughly annular shape. The plurality of driven rollers 51 each has a roughly cylindrical shape. The plurality of driven rollers 51 are supported by the core 53 so as to rotate freely. Specifically, the plurality of driven rollers 51 each rotates freely around an axis of its own position along the tangential direction of the core 53. Hereinafter, the rotation of the driven roller 51 around an axis of its own position along the tangential direction of the core 53 is sometimes referred to as "rotation". The plurality of driven rollers 51 are arranged along the circumferential direction CD relative to the rotation axis AX. In detail, the plurality of driven rollers 51 are arranged on the core 53 at intervals along the circumferential direction CD.

[0046] As the main wheel 5 rotates about the rotation axis AX, the multiple driven rollers 51 each rotate and move in the circumferential direction CD. Hereinafter, the position of the driven rollers 51 in the circumferential direction CD during rotational movement will sometimes be referred to as a "rotational movement position." Depending on the rotational movement position of the driven rollers 51, the multiple driven rollers 51 come into contact with the floor surface or the ground. Hereinafter, contact between the driven rollers 51 and the floor surface or the ground will sometimes be referred to as "grounding." The roller bodies of the driven rollers 51 are made of, for example, rubber.

[0047] Next, refer to Figure 4 and Figure 5 The first driving force transmission device 11A will be described in detail. Figure 4 As shown, the first drive unit DA has a first driving force transmission component 110A. The second drive unit DB has a second driving force transmission component 110B. More specifically, in the present embodiment, the first drive unit DA has a first driving force transmission device 11A, and the first driving force transmission device 11A has a first driving force transmission component 110A. Similarly, in the present embodiment, the second drive unit DB has a second driving force transmission device 11B, and the second driving force transmission device 11B has a second driving force transmission component 110B. Hereinafter, the "first driving force transmission component 110A" and the "second driving force transmission component 110B" are sometimes collectively referred to as the "driving force transmission component 110". The driving force transmission component 110 has a roughly disc shape. The driving force transmission component 110 is made of a high-rigidity material such as metal and hard plastic.

[0048] The driving force transmission member 110 is rotatable about the rotation axis AX. Specifically, when the rotation shaft 171 of the motor 17 rotates, the driving force transmission member 110 rotates about the rotation axis AX. Therefore, the rotation axis AX is also the rotation axis of the driving force transmission member 110.

[0049] Figure 5 : is a perspective view showing the main wheel 5 and the second drive unit DB. Figure 5 In, from Figure 4 The main wheel 5 and the second drive unit DB are viewed from the side of the first drive unit DA. Figure 5 In order to facilitate understanding, the first drive unit DA is omitted. Figure 5 In order to facilitate the observation of the drawings, the main wheel 5 is indicated by a two-dot chain line.

[0050] like Figure 4 and Figure 5As shown, the first drive unit DA has a plurality of first drive rollers 120A. The second drive unit DB has a plurality of second drive rollers 120B. More specifically, in this embodiment, the first drive unit DA has a first driving force transmission device 11A, and the first driving force transmission device 11A has a plurality of first drive rollers 120A. Similarly, in this embodiment, the second drive unit DB has a second driving force transmission device 11B, and the second driving force transmission device 11B has a plurality of second drive rollers 120B. Hereinafter, the "first drive roller 120A" and the "second drive roller 120B" may sometimes be collectively referred to as "drive roller 120". The plurality of drive rollers 120 are arranged on the driving force transmission component 110 along the circumferential direction CD. When the driving force transmission component 110 rotates about the rotation axis AX, the plurality of drive rollers 120 respectively rotate and move along the circumferential direction CD. Hereinafter, the position of the drive roller 120 in the circumferential direction CD when the drive roller 120 rotates and moves along the circumferential direction CD may sometimes be referred to as the "rotational movement position".

[0051] The multiple first drive rollers 120A contact at least a portion of the multiple driven rollers 51 from one side in the axial direction AD. The multiple second drive rollers 120B contact at least a portion of the multiple driven rollers 51 from the other side in the axial direction AD. Specifically, the multiple drive rollers 120 contact any one of the multiple driven rollers 51 depending on the rotational position of the drive rollers 120. At least the drive rollers 120 contact the driven roller 51, which is located at the bottom and grounded. In this case, the outer circumferential surface of the drive rollers 120 contacts the outer circumferential surface of the driven rollers 51. As a result, the friction between the drive rollers 120 and the driven rollers 51 transmits the driving force based on the rotation of the driving force transmission member 110 from the drive rollers 120 to the driven rollers 51. In other words, the rotation of the drive force transmission member 110 transmits the driving force of the motor 17 to the main wheel 5 via the multiple drive rollers 120. In other words, the multiple drive rollers 120 transmit the propulsive force to the main wheel 5.

[0052] Specifically, each of the plurality of drive rollers 120 is arranged so as to be rotatable about a central axis (hereinafter referred to as "central axis CT") extending in a direction that is neither perpendicular nor parallel to the direction of rotation of the main wheel 5 about the rotation axis AX. In other words, the central axis CT of the plurality of drive rollers 120 is inclined relative to the direction of rotation of the main wheel 5 about the rotation axis AX and has a twisted relationship with respect to the rotation axis AX.

[0053] At least a portion 80A of the first motor housing 18A opposes at least a portion of the plurality of first drive rollers 120A in the axial direction AD. In other words, the specific portion 80A and at least a portion of the first drive rollers 120A oppose each other in the axial direction AD, overlapping with each other. At least a portion 80B of the second motor housing 18B opposes at least a portion of the plurality of second drive rollers 120B in the axial direction AD. In other words, the specific portion 80B and at least a portion of the second drive rollers 120B oppose each other in the axial direction AD, overlapping with each other.

[0054] The second drive unit DB further includes a second wheel carrier 13B, at least one second coupling member 14B, and a second speed reducing unit. In this embodiment, the second drive unit DB includes three second coupling members 14B. The second coupling members 14B are, for example, bolts.

[0055] The first drive unit DA also has a first wheel frame, at least one first coupling component and a first deceleration unit. In this embodiment, the first drive unit DA has three first coupling components. In addition, hereinafter, the "first wheel frame" is sometimes referred to as the "first wheel frame 13A" and the "first coupling component" is sometimes referred to as the "first coupling component 14A". Regarding the first deceleration unit and the second deceleration unit, refer to Figure 10 This will be described later. Hereinafter, the "first wheel carrier 13A" and the "second wheel carrier 13B" may be collectively referred to as "wheel carrier 13." Hereinafter, the "first coupling member 14A" and the "second coupling member 14B" may be collectively referred to as "coupling member 14."

[0056] The first wheel frame 13A and the second wheel frame 13B are connected via at least one connecting member 14A and at least one connecting member 14B. Therefore, the first drive unit DA and the second drive unit DB are connected via at least one connecting member 14A and at least one connecting member 14B.

[0057] Next, refer to Figure 4 and Figure 5 The control of the moving direction of the main wheel 5 is described below. Figure 4 As shown, the rotation direction and speed of the first driving force transmission member 110A and the rotation direction and speed of the second driving force transmission member 110B are independently controlled by the first motor 17A and the second motor 17B, thereby controlling the moving direction of the main wheel 5 .

[0058] Specifically, when the first motor 17A and the second motor 17B are driven in the same rotational direction and at the same rotational speed, the first driving force transmission member 110A and the second driving force transmission member 110B rotate at the same rotational speed and in the same rotational direction, thereby rotating the main wheel 5 about the rotation axis AX. In this case, there is no rotational speed difference between the first driving force transmission member 110A and the second driving force transmission member 110B, so the driven roller 51 of the main wheel 5 does not rotate, and the main wheel 5 moves forward or backward in a straight line.

[0059] On the other hand, when the first motor 17A and the second motor 17B are driven in different rotation directions and / or at different rotation speeds, a rotation speed difference occurs between the first driving force transmission member 110A and the second driving force transmission member 110B.

[0060] In this case, a component force perpendicular to the circumferential force based on the rotational force of the first driving force transmission member 110A acts on the driving roller 120 ( Figure 5 ) and the contact surface of the driven roller 51 of the main wheel 5. In addition, a component force perpendicular to the force in the circumferential direction based on the rotational force of the second driving force transmission component 110B acts on the contact surface of the driving roller 120 of the second driving force transmission component 110B and the driven roller 51 of the main wheel 5.

[0061] Therefore, the driven roller 51 rotates without the main wheel 5 rotating about the rotation axis AX, or the main wheel 5 rotates about the rotation axis AX and the driven roller 51 rotates. As a result, the main wheel 5 moves in the left-right direction or the tilt direction.

[0062] The first and second driving force transmission devices 11A and 11B support the main wheel 5 rotatably about the rotation axis AX by sandwiching the main wheel 5 between the plurality of driving rollers 120 of the first and second driving force transmission members 110A and 110B.

[0063] Next, refer to Figure 6A and Figure 6B The driving roller 120 will be described. Figure 6A It is a perspective view showing the driving roller 120 . Figure 6B FIG is a top view showing the driving roller 120. Figure 6A and Figure 6BAs shown, the drive roller 120 includes a roller body 121 and a shaft 123. The roller body 121 has a generally circular plate shape. It is made of a highly rigid material, such as metal or rigid plastic. The shaft 123 is disposed on the central axis CT. That is, the shaft 123 extends along the central axis CT. The shaft 123 has a generally cylindrical shape. It penetrates the roller body 121 and is fixed to the roller body 121. The shaft 123 is made of a highly rigid material, such as metal or rigid plastic.

[0064] Here, the driving force transmission device 11 ( Figure 5 ) has a pair of bushings BH and a pair of pads 125 for one driving roller 120. The first driving force transmission device 11A has a plurality of bushings BH and a plurality of pads 125 because it has a plurality of driving rollers 120.

[0065] A pair of bushings BH rotatably supports the drive roller 120 about the central axis CT. Specifically, one bushing BH rotatably supports one end of the shaft 123, while the other bushing BH rotatably supports the other end of the shaft 123. The bushings BH are made of a highly rigid material such as metal or rigid plastic.

[0066] The pair of pads 125 are each made of an elastic member such as rubber. Furthermore, one pad 125 is sandwiched between one side surface 121a of the roller body 121 and the bushing BH, while the other pad 125 is sandwiched between the other side surface 121a of the roller body 121 and the bushing BH. As a result, the generation of noise caused by the drive roller 120 when the drive force transmission member 110 rotates about the rotation axis AX can be suppressed.

[0067] Next, refer to Figure 3 、 Figure 7A as well as Figure 7B The attachment of the rotary drive device DV to the vehicle body 3 of the transport vehicle 1 will be described. Figure 7A and Figure 7B 1 is a perspective view showing a portion of the vehicle body 3 of the rotary drive device DV and the transport vehicle 1. Figure 7A As shown, for example, a specific portion 80A and a specific portion 80B can each be attached to the vehicle body 3 . That is, both the specific portion 80A and the specific portion 80B can be attached to the vehicle body 3 .

[0068] The vehicle body 3 can be, for example, the shell of the transport vehicle 1 or a connecting member. A connecting member connects the specific portion 80 to the shell of the transport vehicle 1. In other words, the vehicle body 3 can include all components of the transport vehicle 1 except the rotary drive device DV. The vehicle body 3 has a contact surface with the specific portion 80.

[0069] The specific portion 80 only needs to be attached to the vehicle body 3 at a height at which the driven roller 51 can touch the ground. For example, it can be attached to the bottom 3a, which is the lower part of the vehicle body 3, or to the side of the vehicle body 3. The specific portion 80 is fixed in contact with the contact surface of the vehicle body 3, for example, by bolts (not shown).

[0070] As described above, according to this embodiment, both the specific portion 80A and the specific portion 80B can be mounted on the vehicle body 3 and are preferably arranged to oppose at least a portion of the plurality of first drive rollers 120A and at least a portion of the plurality of second drive rollers 120B in the axial direction AD. This is because, even in a configuration where the motor 17 is positioned overlapping the rotation axis AX in the axial direction AD, the first drive unit DA and the second drive unit DB can be positioned at highly precise opposing positions, while also minimizing the expansion of the mounting space in the axial direction AD.

[0071] Furthermore, according to this embodiment, the rotational drive device DV only needs to be mountable to the vehicle body 3. For example, at least one of the specific portion 80A and the specific portion 80B can be mounted to the vehicle body 3. Furthermore, as a pair of drive units DP, the second drive unit DB preferably has the same structure as the first drive unit DA. This is to improve the coaxiality between the first drive unit DA and the second drive unit DB. This improves the stability of the transport vehicle 1 during travel.

[0072] In addition, if Figure 7B As shown, according to this embodiment, only one of the pair of drive units DP can be mounted on the vehicle body 3. For example, only a specific portion 80A of the pair of drive units DP can be mounted on the vehicle body 3. By arranging the specific portion 80A opposite at least a portion of the plurality of first drive rollers 120A in the axial direction AD, the expansion of the mounting space in the axial direction AD can be reduced. Consequently, the space required for mounting on the vehicle body 3 can be reduced, thereby contributing to space savings.

[0073] Next, refer to Figure 8A and Figure 8B The structure of the motor case 18 will be described in detail. Figure 8A It is a perspective view showing the motor case 18 . Figure 8B 1 is a cross-sectional view showing the motor housing 18. Figure 8B In FIG. 1 , the motor 17 is simplified and indicated by hatching in order to facilitate understanding of the outer shape of the motor housing 18 .

[0074] like Figure 8A and Figure 8BAs shown, the first motor housing 18A preferably has a first main body portion 181A and a first flange portion 182A. Similarly, the second motor housing 18B preferably has a second main body portion 181B and a second flange portion 182B. Hereinafter, the "first main body portion 181A" and the "second main body portion 181B" are sometimes collectively referred to as the "main body portion 181". In addition, the "first flange portion 182A" and the "second flange portion 182B" are sometimes collectively referred to as the "flange portion 182". The main body portion 181 is in the shape of a roughly bottomed cylinder extending along the rotation axis AX. The main body portion 181 accommodates the motor 17. The flange portion 182 extends from the main body portion 181 toward the outside in the radial direction RD relative to the rotation axis AX. A specific portion 80 constitutes the flange portion 182. According to this embodiment, the specific portion 80 can be configured to avoid the motor 17 in the radial direction RD. Therefore, in the pair of drive portions DP, the rotation drive device DV can be efficiently mounted on the vehicle body 3 without expanding in the axial direction AD toward the mounting position of the vehicle body 3. Furthermore, it is possible to reduce the chance of foreign matter from outside coming into contact with or entering the drive roller 120.

[0075] In addition, the first flange portion 182A preferably has a plurality of first mounting holes 188A. Similarly, the second flange portion 182B preferably has a plurality of second mounting holes 188B. Hereinafter, the "first mounting holes 188A" and the "second mounting holes 188B" may sometimes be collectively referred to as "mounting holes 188." The plurality of mounting holes 188 are arranged in the flange portion 182, for example, at equal intervals along the circumferential direction CD. The mounting holes 188 are, for example, through holes or threaded holes extending along the rotation axis AX. The vehicle body 3 can be mounted to the mounting holes 188 using bolts. Therefore, the flange portion 182 can be easily fixed to the vehicle body 3. In addition, there may be only one mounting hole 188.

[0076] Next, refer to Figure 9 An example of a specific part 80 is described. The specific part 80A and the specific part 80B are preferably the first front bracket FBA and the second front bracket FBB, respectively. Hereinafter, the "first front bracket FBA" and the "second front bracket FBB" are sometimes collectively referred to as "front bracket FB". In addition, the "portion after removing the first front bracket FBA from the first motor housing 18A and the first motor 17A" and the "portion after removing the second front bracket FBB from the second motor housing 18B and the second motor 17B" are sometimes referred to as "first motor part MTA" and "second motor part MTB", respectively. Furthermore, the "first motor part MTA" and the "second motor part MTB" are sometimes collectively referred to as "motor part MT". Figure 918 is an exploded perspective view showing the motor unit MT and the front bracket FB. The “portion obtained by removing the motor 17 from the motor unit MT” and the “portion obtained by removing the flange portion 182 from the front bracket FB” constitute the main body 181 .

[0077] like Figure 9 As shown, the front bracket FB is a substantially annular member, such as a ring. The front bracket FB is made of, for example, metal or resin. It substantially closes the opening of the motor unit MT. The front bracket FB has a plurality of holes 183 and a plurality of holes 184. A specific portion 80 forms the outer end of the front bracket FB in the radial direction RD relative to the rotation axis AX. In other words, the specific portion 80 forms the flange portion 182.

[0078] Next, refer to Figure 9 And further refer to Figure 10 and Figure 11 , the first speed reduction unit 15A, the second speed reduction unit 15B, the front bracket FB, and the motor 17 will be described in detail. Figure 10 It is along Figure 4 Cross-sectional view of line XX. Figure 11 It is along Figure 4 The cross-sectional view of the XI-XI line. Figure 10 As shown, the first drive unit DA and the second drive unit DB further include a first reduction gear 15A and a second reduction gear 15B, respectively.

[0079] The first speed reduction unit 15A is arranged on the load side D1A in the axial direction AD relative to the first motor housing 18A. Specifically, the load side D1A refers to the side of the first motor 17A to which the load is connected. The opposite side of the load side D1A of the first motor 17A is the counter-load side D2A. Figure 10 In FIG. 1 , the load side D1A and the counter-load side D2A relative to the first motor 17A are the right direction side and the left direction side, respectively.

[0080] Similar to the first speed reduction unit 15A, the second speed reduction unit 15B is arranged on the load side D1B in the axial direction AD relative to the second motor housing 18B. Specifically, the load side D1B refers to the side of the second motor 17B to which the load is connected. In addition, the opposite side of the load side D1B of the second motor 17B is the counter-load side D2B. Figure 10 In FIG. 1 , the load side D1B and the counter-load side D2B with respect to the second motor 17B are the left direction side and the right direction side, respectively.

[0081] The front bracket FB connects the motor unit MT and the reduction unit 15. Specifically, the front bracket FB is connected to the motor unit MT. The motor unit MT is fixed to the plurality of holes 183 of the front bracket FB with bolts. The front bracket FB is connected to the reduction unit 15. The reduction unit 15 is fixed to the plurality of holes 184 of the front bracket FB. According to this embodiment, the specific portion 80 is the front bracket FB, thereby suppressing an increase in the number of components used to mount the rotary drive device DV on the vehicle body 3 and suppressing expansion of the mounting position in the axial direction AD. Furthermore, the thickness of the motor unit MT in the axial direction AD can be reduced.

[0082] The first reduction unit 15A includes a first sun gear 151A, a plurality of first planetary gears 153A, a first internal gear 155A, and a plurality of bearings. The second reduction unit 15B includes a second sun gear 151B, a plurality of second planetary gears 153B, a second internal gear 155B, and a plurality of bearings. Hereinafter, the "first sun gear 151A" and the "second sun gear 151B" may sometimes be collectively referred to as "sun gear 151." In addition, in the following, the "first planetary gears 153A" and the "second planetary gears 153B" may sometimes be collectively referred to as "planetary gears 153." In addition, in the following, the "first internal gear 155A" and the "second internal gear 155B" may sometimes be collectively referred to as "internal gear 155."

[0083] The speed reduction unit 15 converts rotational motion at a rotational speed N1 into rotational motion at a lower rotational speed N2. The rotational speeds N1 and N2 represent the rotational speeds per unit time. In this embodiment, the speed reduction unit 15 reduces the rotational speed of the rotating shaft 171 and rotates the driving force transmission member 110 at the reduced speed.

[0084] The reduction unit 15 transmits power by rotating the sun gear 151 and the plurality of planetary gears 153 while they are in contact with each other. In other words, the reduction unit 15 is a so-called planetary gear type reduction unit. Specifically, the reduction unit 15 is a planetary gear type reduction unit with a star-shaped structure. Specifically, the external teeth of each of the plurality of planetary gears 153 mesh with the internal teeth of the internal gear 155. The internal gear 155 constitutes a portion of the driving force transmission component 110. Therefore, when the plurality of planetary gears 153 rotate, the driving force transmission component 110 rotates.

[0085] The carrier 13 accommodates at least a portion of the speed reduction unit 15. In the present embodiment, the carrier 13 accommodates a portion of the rotating shaft 171, the sun gear 151, and the plurality of planetary gears 153.

[0086] The first motor 17A includes a first rotating shaft 171A, a first magnet 172A, a first rotor yoke 173A, and a first stator 700A. The first stator 700A includes a first stator core 710A, multiple first insulators 720A, and multiple first coils 730A. The second motor 17B includes a second rotating shaft 171B, a second magnet 172B, a second rotor yoke 173B, and a second stator 700B. The second stator 700B includes a second stator core 710B, multiple second insulators 720B, and multiple second coils 730B.

[0087] Hereinafter, the "first magnet 172A" and the "second magnet 172B" may be collectively referred to as "magnet 172." Hereinafter, the "first rotor yoke 173A" and the "second rotor yoke 173B" may be collectively referred to as "rotor yoke 173." Hereinafter, the "first stator 700A" and the "second stator 700B" may be collectively referred to as "stator 700." Hereinafter, the "first stator core 710A" and the "second stator core 710B" may be collectively referred to as "stator core 710." Hereinafter, the "first insulator 720A" and the "second insulator 720B" may be collectively referred to as "insulator 720." Hereinafter, the "first coil 730A" and the "second coil 730B" may be collectively referred to as "coil 730."

[0088] The motor 17 is, for example, an inner rotor type motor. The rotating shaft 171, the magnet 172, and the rotor yoke 173 rotate around the rotating axis AX. The magnet 172 is, for example, a permanent magnet. The magnet 172 is fixed to the radially outer surface RD of the rotor yoke 173. Therefore, the motor 17 is a so-called SPM (Surface Permanent Magnet) motor. The rotating shaft 171 is arranged around the central axis. In detail, the rotating shaft 171 is arranged on the rotating axis AX and extends in the axial direction AD. Hereinafter, the rotating axis AX is sometimes referred to as the "central axis AX" of the motor 17. The rotating shaft 171 is roughly columnar. "Columnar" means, for example, "cylindrical". When the motor 17 is driven, the rotating shaft 171 rotates at a rotation speed N1 around the central axis AX. The rotating shaft 171 is fixed to the rotor yoke 173. Therefore, the rotating shaft 171 rotates around the central axis AX together with the rotor yoke 173 and the magnet 172.

[0089] The stator 700 and the magnet 172 are opposed to each other in the radial direction RD. The stator 700 is arranged around the central axis AX.

[0090] The stator core 710 is roughly annular with the central axis AX as the center. "Annular" means, for example, "circular ring shape". The insulators 720 are respectively installed on at least a portion of the stator core 710. The insulators 720 are respectively arranged between the coils 730 and the stator core 710. Therefore, the coils 730 are respectively installed on the stator core 710 via the insulators 720. The insulators 720 are made of insulators. Therefore, the insulators 720 electrically insulate the stator core 710 from the coils 730. The stator core 710 is, for example, made of laminated steel plates formed by stacking electromagnetic steel plates in the axial direction AD. The specific portion 80 is, for example, arranged at a position closer to the outside of the radial direction RD relative to the rotating shaft 171 than the stator core 710. In addition, the front bracket FB is, for example, arranged between the stator 700 and the speed reduction unit 15 in the axial direction AD.

[0091] Furthermore, the specific portion 80A is preferably located closer to the load side D1A than the center portion 18A3 between the end surface 18A1 on the opposite side D2A of the first motor housing 18A and the end surface 18A2 on the load side D1A in the axial direction AD. Specifically, the distance WA2 between the end surface 18A2 and the center portion 18A3 is equal to the distance WA3 between the end surface 18A1 and the center portion 18A3. Within the distance WA1 between the end surfaces 18A1 and 18A2, the specific portion 80A is located within the distance WA2. Furthermore, the specific portion 80B is preferably located closer to the load side D1B than the center portion 18B3 between the end surface 18B1 on the opposite side D2B of the second motor housing 18B and the end surface 18B2 on the load side D1B in the axial direction AD. Specifically, the distance WB2 between the end surface 18B2 and the center portion 18B3 is equal to the distance WB3 between the end surface 18B1 and the center portion 18B3. A specific portion 80B of the gap WB1 between the end surface 18B1 and the end surface 18B2 is located at the gap WB2. According to these preferred examples, the vehicle body 3 can be mounted at a position closer to the load side D1A, D1B relative to the rotary drive device DV. Therefore, the space required for mounting the rotary drive device DV on the vehicle body 3 can be further narrowed in the axial direction AD. In particular, in the case of Figure 7B When the vehicle body 3 is attached to only one side of the rotation drive device DV as shown, that is, when the vehicle body 3 is attached to only the specific portion 80A or the specific portion 80B, the moment load that tends to be generated can be reduced.

[0092] Figure 11 As an example, the rotation drive device DV is shown in which the vehicle body 3 is mounted only on a specific portion 80A. Figure 11As shown, when a load P is applied to the vehicle body 3 while the rotary drive device DV is mounted on the running surface G, a load is applied to the main wheels 5. The stress caused by the load generates a moment load at the load point PA of the specific portion 80A. The running surface G is, for example, a floor or ground surface. Generally, the moment load applied to the load point tends to increase as the distance from the centerline BX of the rotary drive device DV to the load point increases. For example, if the specific portion 80A is located closer to the load side D1A than the center portion 18A3 between the end surface 18A1 on the anti-load side D2A and the end surface 18A2 on the load side D1A of the first motor case 18A in the axial direction AD, the distance LA from the specific portion 80A to the centerline BX is smaller than the distance LLA from the end surface 18A1 to the centerline BX. Therefore, the moment load when the vehicle body 3 is mounted on the specific portion 80A or the specific portion 80B is smaller than the moment load when the vehicle body 3 is mounted on the end surface 18A1 or the end surface 18B1. In other words, the closer the specific portion 80 is positioned to the load side D1A or the load side D1B relative to the motor 17 in the axial direction AD, the lower the moment load generated when the vehicle body 3 is mounted on the specific portion 80. As a result, the rigidity required of components such as the vehicle body 3 and the specific portion 80 can be reduced.

[0093] Next, refer to Figure 12 and Figure 13 Modifications of the motor case 18 will be described. Figure 12 It is a side view showing a rotation drive device DV according to a modified example of the present embodiment. Figure 13 It is along Figure 12 The cross-sectional view of the XIII-XIII line. Figure 12 and Figure 13 As shown, the motor housing 18 has a cylindrical shape extending in the axial direction AD. In this variation, the motor housing 18 further includes a recessed area 185. More specifically, in this embodiment, the motor housing 18 includes a main body 181, which includes the recessed area 185. Furthermore, in this variation, the motor housing 18 may or may not include a flange 182. The recessed area 185 is an area that is recessed inward in the radial direction RD relative to the rotation axis AX.

[0094] The specific portion 80 overlaps with the recessed area 185 in the axial direction AD. The specific portion 80 is, for example, in the shape of a rectangular plate and extends in the radial direction RD. There are preferably multiple specific portions 80, for example, four or one. A mounting hole 188 is provided in the specific portion 80. The vehicle body 3 is mounted to the specific portion 80 using, for example, bolts 31. By arranging the specific portion 80 so that it overlaps with the recessed area 185, it is possible to further suppress expansion of the width of the motor housing 18 in the radial direction RD relative to the rotation axis AX and to mount the rotary drive device DV on the vehicle body 3. Consequently, the space required for mounting on the vehicle body 3 can be further reduced.

[0095] Next, refer to Figure 14 Still another modification of the motor case 18 will be described. Figure 14 1 is a cross-sectional view showing a rotation drive device DV according to a modified example of the present embodiment. Figure 14 The rotary drive device DV is partially shown in FIG.

[0096] like Figure 14 As shown, the first flange portion 182A further includes a first mounting portion 186A and a first cover portion 187A. The second flange portion 182B further includes a second mounting portion 186B and a second cover portion 187B. Hereinafter, the "first mounting portion 186A" and the "second mounting portion 186B" may be collectively referred to as "mounting portion 186." Furthermore, the "first cover portion 187A" and the "second cover portion 187B" may be collectively referred to as "cover portion 187."

[0097] The mounting portion 186 extends from the main body 181 toward the outside in the radial direction RD. The mounting portion 186 can be mounted on the vehicle body 3. In other words, a specific portion 80 constitutes the mounting portion 186. The cover portion 187 is arranged on the outside in the radial direction RD of the driving roller 120 relative to the rotation axis AX. The cover portion 187 extends from the mounting portion 186 toward the driven roller 51. The cover portion 187 and the mounting portion 186 can be independent components or parts of one component. The cover portion 187 is, for example, annular such as a cylinder. In addition, the cover portion 187 is not limited to annular shape, and for example, it can also partially extend from the end portion on the outside in the radial direction RD of the mounting portion 186 toward the driven roller 51. The cover portion 187 extends, for example, along the axial direction AD. In addition, the cover portion 187 can also extend obliquely toward the outside in the radial direction RD relative to the axial direction AD. By extending the cover portion 187 from the mounting portion 186 toward the driven roller 51, it is possible to further reduce the possibility of foreign matter from the outside coming into contact with or entering the driving roller 120.

[0098] Furthermore, the cover portion 187 is preferably disposed vertically below the driving roller 120. Specifically, it is particularly effective to dispose the cover portion 187 vertically below the driving roller 120 when the cover portion 187 partially extends from the radially outer end portion of the mounting portion 186 toward the driven roller 51. This is to effectively reduce the possibility of foreign matter that bounces up from the travel surface G side of the rotary drive device DV coming into contact with or entering the driving roller 120.

[0099] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the above-mentioned embodiments and can be implemented in various ways without departing from the main purpose thereof. In addition, various inventions can be formed by appropriately combining multiple components of multiple embodiments. For example, several components can be deleted from all the components shown in the embodiments. In addition, the components of different embodiments can also be appropriately combined. For ease of understanding, the drawings are schematically shown with each component as the main body. For the convenience of making the drawings, the thickness, length, number, spacing, etc. of each component shown in the drawings are different from the actual ones. In addition, the speed, material, shape, size, etc. of each component shown in the above-mentioned embodiment are only examples and are not particularly limited. Various changes can be made within the scope of the structure of the present invention.

[0100] (1) In reference Figures 1 to 14 In the embodiment described above, the rotation drive device DV ( Figure 3 ) is applied to a transport vehicle 1. However, the application of the rotation drive device DV is not limited to the transport vehicle 1. The rotation drive device DV can be applied to any mobile object that moves on a floor or ground surface. Examples of mobile objects include a unicycle, a two-wheeled vehicle, a three-wheeled vehicle, or a four-wheeled vehicle. Furthermore, a mobile object may have one rotation drive device DV or two or more rotation drive devices DV.

[0101] (2) In reference Figures 1 to 14 In the embodiment described above, the rotation axis AX of the main wheel 5 is substantially aligned with the rotation axis AX of the motor 17. However, the rotation axis AX of the motor 17 may be eccentric with respect to the rotation axis of the main wheel 5.

[0102] Industrial applicability

[0103] The present invention can be used, for example, in a rotary drive device.

Claims

1. A rotation drive device, which is arranged on a moving body, wherein: The rotary drive device has: a main wheel rotatable about an axis of rotation; as well as a pair of driving parts, which are opposed to each other in the axial direction along the rotation axis and respectively drive the main wheel, The main wheel has a plurality of driven rollers arranged along a circumferential direction relative to the rotation axis. The first driving unit as one of the pair of driving units includes: First Motor; a first motor housing housing the first motor; a first driving force transmitting member that rotates about the rotation axis; as well as a plurality of first driving rollers arranged along the circumferential direction on the first driving force transmission member and contacting at least a portion of the plurality of driven rollers from one side in the axial direction; The first driving force transmission member rotates to transmit the driving force of the first motor to the main wheel via the plurality of first driving rollers. At least a portion of the first motor housing is opposed to at least a portion of the plurality of first driving rollers in the axial direction. The at least a portion of the first motor housing is in direct contact with a main body of the mobile object and can be directly mounted on the main body of the mobile object.

2. The rotary drive device according to claim 1, wherein: The second drive unit, which is the other of the pair of drive units, includes: Second motor; a second motor housing for accommodating the second motor; a second driving force transmitting member that rotates about the rotation axis; as well as a plurality of second driving rollers arranged along the circumferential direction on the second driving force transmission member and contacting at least a portion of the plurality of driven rollers from the other side in the axial direction; The second driving force transmission member rotates to transmit the driving force of the second motor to the main wheel via the plurality of second driving rollers. At least a portion of the second motor housing is opposed to at least a portion of the plurality of second drive rollers in the axial direction. At least one of the at least a portion of the first motor housing and the at least a portion of the second motor housing is attachable to the vehicle body.

3. The rotary drive device according to claim 2, wherein: Both the at least a portion of the first motor housing and the at least a portion of the second motor housing can be mounted on the vehicle body.

4. The rotary drive device according to claim 2 or 3, wherein: The at least a portion of the first motor housing is located closer to the load side than a center portion between an end surface on the anti-load side and an end surface on the load side of the first motor housing in the axial direction. The at least a portion of the second motor housing is located closer to the load side than a center portion between an end surface on the anti-load side and an end surface on the load side of the second motor housing in the axial direction.

5. The rotary drive device according to claim 2 or 3, wherein: The first motor housing is in a cylindrical shape extending along the axial direction. The at least one portion of the first motor housing overlaps with a recessed region that is recessed radially inward relative to the rotation axis in the axial direction. The second motor housing is in a cylindrical shape extending along the axial direction. The at least a portion of the second motor housing overlaps with a recessed region that is recessed radially inward with respect to the rotation axis in the axial direction.

6. The rotary drive device according to claim 2 or 3, wherein: The first driving unit further includes a first speed reducing unit, which is arranged on the load side of the first motor housing in the axial direction and reduces the rotation speed of the output shaft of the first motor. At least a portion of the first motor housing is a front bracket connected to the first speed reducing unit. The second driving unit further includes a second speed reducing unit, which is arranged on the load side of the second motor housing in the axial direction and reduces the rotation speed of the output shaft of the second motor. The at least one portion of the second motor housing is a front bracket connected to the second speed reducing portion.

7. The rotary drive device according to claim 2 or 3, wherein: The first motor housing has: a first main body portion housing the first motor; and a first flange portion extending from the first main body portion toward the radially outer side relative to the rotation axis, The at least one portion of the first motor housing constitutes the first flange portion, The second motor housing has: a second main body portion accommodating the second motor; and A second flange portion extends from the second main body portion toward the outside in the radial direction relative to the rotation axis, and the at least a portion of the second motor housing constitutes the second flange portion.

8. The rotary drive device according to claim 7, wherein: The first flange portion has: a first mounting portion, which can be mounted on the mobile body; and a first cover portion arranged radially outward of the first driving roller relative to the rotation axis, The first cover portion extends from the first mounting portion toward the driven roller, The second flange portion has: a second mounting portion, which can be mounted on the mobile body; and a second cover portion disposed radially outward of the second driving roller relative to the rotation axis, The second cover portion extends from the second mounting portion toward the driven roller.

9. The rotary drive device according to claim 8, wherein: The first cover portion is arranged vertically below the first driving roller. The second cover portion is arranged vertically below the second driving roller.

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