Drive unit of unmanned transport vehicle

Abstract

This invention relates to a drive unit for an unmanned transport vehicle, comprising: a crown wheel (turning gear) fixed to the bottom of the vehicle body; a spindle extending vertically from the vehicle body through the center of the crown wheel; a frame supported on the spindle in a manner that allows rotation in a horizontal plane; a wheel axle rotatably mounted on the frame; and wheels connected to the wheel axles. The drive unit of the unmanned transport vehicle is characterized by being configured as follows: a first motor and a second motor, serving as drive sources, a first planetary gear mechanism, and a second planetary gear mechanism are respectively arranged at both axial ends of the wheel axle; each planet carrier of the first planetary gear mechanism and the second planetary gear mechanism is respectively connected to the wheel axle; and the gear rings of the first planetary gear mechanism and the second planetary gear mechanism respectively mesh with the crown wheel.

Description

Technical Field

[0001] This invention relates to a drive unit for an unmanned transport vehicle in which a planetary gear mechanism is provided in the power transmission path of an electric motor that serves as the drive source. Background Technology

[0002] Automated Guided Vehicles (AGVs) are widely used in the transportation of raw materials, parts, and finished products, with the production site as the center. They have also been widely introduced into various non-manufacturing fields, such as product storage, logistics centers for outbound shipments, and hospitals.

[0003] Furthermore, due to the remarkable advancements in artificial intelligence and control in recent years, intelligent unmanned transport vehicles capable of cooperating with humans have emerged in workshops, homes, public places, and other similar environments. When such unmanned transport vehicles operate in complex environments or confined spaces, their omnidirectional mobility is highly advantageous. As such an omnidirectional unmanned transport vehicle, omnidirectional wheels (caster wheels) comprising passive rollers perpendicular to the wheel axle and rollers oriented at a 45° angle (Mecanum wheels) have been proposed and are already in practical use.

[0004] However, traditional omnidirectional wheels have problems such as complex manufacturing, weak resistance to road surface unevenness, and limited load capacity, which restricts their application.

[0005] Therefore, ordinary wheels with both driving and turning functions are currently in use. In order to achieve the driving and turning of the wheels, a drive unit with a driving motor for driving and a turning motor for steering is used (see, for example, Patent Document 1 and Patent Document 2).

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 60-078831

[0009] Patent Document 2: U.S. Patent No. 6491127 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, if a structure is adopted in which the drive motor and the turning motor are set up independently, these drive motors and turning motors operate independently, thus requiring additional driving force. Therefore, there are problems such as the drive unit equipped with these drive motors becoming larger and consuming more power.

[0012] The present invention was made in view of the aforementioned problems, and its object is to provide a drive unit that enables energy saving and small-compact unmanned transport vehicles.

[0013] Technical means to solve the problem

[0014] The drive unit of the unmanned transport vehicle of the first invention includes: a turning gear fixed to the bottom of the vehicle body; a spindle extending vertically from the vehicle body through the center of the turning gear; a frame supported on the spindle in a manner that allows it to rotate in a horizontal plane; a wheel axle rotatably mounted on the frame; and a wheel connected to the wheel axle. The drive unit of the unmanned transport vehicle is configured such that a first motor and a second motor, a first planetary gear mechanism and a second planetary gear mechanism serving as drive sources are respectively arranged at both axial ends of the wheel axle, and each planet carrier of the first planetary gear mechanism and the second planetary gear mechanism is respectively connected to the wheel axle, and the gear rings of the first planetary gear mechanism and the second planetary gear mechanism respectively mesh with the turning gear.

[0015] Furthermore, the drive unit of the unmanned transport vehicle of the second invention includes: a turning gear fixed to the bottom of the vehicle body; a spindle extending vertically from the vehicle body through the center of the turning gear; a frame supported on the spindle in a manner that allows it to rotate in a horizontal plane; a wheel axle rotatably mounted on the frame; and a wheel connected to the wheel axle. The drive unit of the unmanned transport vehicle is configured such that: a motor and a planetary gear mechanism serving as a drive source are arranged at one axial end of the wheel axle; a first brake is installed at the other axial end of the wheel axle; a second brake is installed on the spindle; the planet carrier of the planetary gear mechanism is connected to the wheel axle; and the ring gear of the planetary gear mechanism meshes with the turning gear.

[0016] The effects of the invention

[0017] According to the first invention, the driving force of the first motor and the second motor pair is used for both the movement and turning of the unmanned transport trolley, so the driving force required by each motor can be smaller, thereby achieving miniaturization and energy saving of these first motors and second motors. As a result, energy saving and miniaturization and compactness of the drive unit can be achieved.

[0018] According to the second invention, the unmanned transport vehicle is driven by a motor to move and turn, thus enabling further miniaturization and energy saving of the motor, thereby achieving further energy saving and miniaturization / compactness of the drive unit. Attached Figure Description

[0019] Figure 1 A perspective view of the drive unit of the unmanned transport vehicle of the first invention.

[0020] Figure 2 This is a longitudinal cross-sectional view of the drive unit of the unmanned transport vehicle of the first invention.

[0021] Figure 3 An exploded perspective view of the motor and planetary gear mechanism of the drive unit of the unmanned transport vehicle of the first invention.

[0022] Figure 4 A diagram illustrating the structure of the drive system of the drive unit of the unmanned transport vehicle of the first invention.

[0023] Figure 5 This is a diagram showing the angular velocities of the various rotational elements of the drive unit of the unmanned transport vehicle of the first invention in tabular form.

[0024] Figure 6 A perspective view of the drive unit of the unmanned transport vehicle of the second invention.

[0025] Figure 7 This is a longitudinal cross-sectional view of the drive unit of the unmanned transport vehicle of the second invention.

[0026] Figure 8 A diagram illustrating the structure of the drive system of the drive unit of the unmanned transport vehicle of the second invention.

[0027] Figure 9 This is a diagram showing the angular velocity values ​​of each rotational element of the drive unit of the unmanned transport vehicle of the second invention and the on / off state of the brakes, in tabular form.

[0028] Explanation of symbols

[0029] 1. 1A: Drive unit

[0030] 2: Crown Gear (Rotating Gear)

[0031] 3: Mandrel

[0032] 4: Framework

[0033] 4A: Top Slab

[0034] 4B: Side panel

[0035] 5: Collar Components

[0036] 6: Bolts

[0037] 7, 14, 15, 17, 18, 21, 22: Bearings

[0038] 8: Wheel and axle

[0039] 9: Wheels

[0040] 10: Ring plate

[0041] 11: Motor housing

[0042] 12: Stator

[0043] 13: Rotor

[0044] 16: Axis

[0045] 19, 20: Intermediate shaft

[0046] 23, 24: Intermediate gears

[0047] 25: Gear

[0048] 26: End-drive gear

[0049] 30: ECU (Electronic Control Unit)

[0050] 100: The body of the unmanned delivery vehicle

[0051] Br1: First brake

[0052] Br2: Second brake

[0053] FL: Ground

[0054] G: Planetary gear mechanism

[0055] G1: First planetary gear mechanism

[0056] G2: Second planetary gear mechanism

[0057] M: Motor

[0058] M1: First Motor

[0059] M2: Second Motor

[0060] c, c1, c2: Planetary support

[0061] p, p1, p2: Planetary gears

[0062] r, r1, r2: gear ring

[0063] s, s1, s2: Sun gear

[0064] ω1~ω7: angular velocity Detailed Implementation

[0065] [First Invention]

[0066] First, the following is based on Figures 1-5 The first invention will be described.

[0067] Figure 1 A perspective view of the drive unit of the unmanned transport vehicle of the first invention. Figure 2 This is a longitudinal cross-sectional view of the drive unit. Figure 3This is an exploded perspective view of the motor and planetary gear mechanism of the drive unit. Figure 4 A diagram illustrating the structure of the drive system of the drive unit. Figure 5 This is a diagram showing the angular velocity values ​​of each rotational element of the drive unit in tabular form.

[0068] Figure 1 and Figure 2 The drive unit 1 shown is installed on the body 100 of the unmanned transport vehicle (see reference). Figure 2 The bottom of the unmanned transport vehicle is positioned on the ground FL (refer to the bottom of the vehicle). Figure 2 The system is designed for driving and turning, and actually includes multiple units. Furthermore, each drive unit 1 has the same structure and function; therefore, the structure and function of one drive unit 1 will be explained below.

[0069] A large-diameter crown wheel 2, serving as a turning gear, is horizontally and tightly fixed to the bottom of the vehicle body 100 of the unmanned transport vehicle. A spindle 3, extending vertically downwards from the bottom surface of the vehicle body 100, passes through the center of the crown wheel 2. Furthermore, the upper central portion of the portal frame 4 is supported on the spindle 3 in a manner that allows it to rotate horizontally around the spindle 3. Specifically, as... Figure 2 As shown, a cylindrical collar member 5 penetrates the center of the top plate 4A of the frame 4, and the collar member 5 is connected by multiple bolts 6 ( Figure 2 (Only two are shown in the figure) are fixed to the top plate 4A of the frame 4. Furthermore, the collar member 5 is rotatably supported by two upper and lower bearings 7 on a spindle 3 inserted from above into the collar member 5. Thus, as described above, the frame 4 is supported in a manner that allows it to rotate in the horizontal plane around the spindle 3.

[0070] Here, a pair of side plates 4B extending parallel to each other vertically downward from the top plate 4A are provided on the frame 4, and the axle 8 is horizontally mounted across the lower part of these side plates 4B in a rotatable manner. Furthermore, a wheel (drive wheel) 9 that rolls on the ground FL is inserted and fixed to the axial center of the axle 8, and a portion of the wheel 9 is housed within the frame 4.

[0071] In addition, such as Figure 2 As shown, at both ends of the axial direction of the axle 8 ( Figure 2 At the left and right ends of the wheel 9, a first motor M1 and a second motor M2, serving as drive sources, are respectively arranged. On the inner side of each of these first electric motors M1 and second motors M2, a first planetary gear mechanism G1 and a second planetary gear mechanism G2 are respectively arranged. That is, with the wheel 9 as the center, on both sides of it... Figure 2The first motor M1 and the second motor M2, as well as the first planetary gear mechanism G1 and the second planetary gear mechanism G2, are symmetrically arranged in two parts (left and right). Here, the structure of the first motor M1 and the first planetary gear mechanism G1 will be described. Furthermore, the structure of the second motor M2 is the same as that of the first motor M1, so the same symbols are used for the same elements and descriptions of their equivalents are omitted. Additionally, the structure of the second planetary gear mechanism G2 is also the same as that of the first planetary gear mechanism G1, but in the second planetary gear mechanism G2, the sun gear is shown as s2, the ring gear as r2, the planetary gears as p2, and the planet carrier as c2.

[0072] like Figure 2 As shown, the first motor M1 is small and thin, an energy-saving, reversible motor, and is constructed by housing a stator 12 and a rotor 13 within a motor housing 11 mounted on a side plate 4B of the frame 4 via an annular plate 10. Here, a three-phase coil (not shown) is wound and mounted on the stator 12, and a hollow shaft-shaped rotor (motor output shaft) 13 is fitted onto one end of the axle 8. Furthermore, the rotor 13 is rotatably supported on the motor housing 11 by bearings 14.

[0073] In addition, such as Figure 2 and Figure 3 As shown, the first planetary gear mechanism G1 includes a small-diameter sun gear s1, a large-diameter ring gear r1, and three planetary gears p1 (see reference). Figure 3 The rotor 13 is composed of a planetary carrier c1 and a small-diameter sun gear s1 mounted on the outer periphery of one end facing the frame 4. A large-diameter ring gear r1 is arranged around the sun gear s1. Three planetary gears p1 mesh with the sun gears s1 and the ring gear r1, rotating on their own axis and revolving around the same axis. The planetary carrier c1 rotatably (rotatably) supports the planetary gears p1 via bearings 15 and shaft 16. Here, the planetary carrier c1 is connected at its center to the outer periphery of the axle 8 and is supported on the rotor 13 by bearings 17 in a rotatable manner. In addition, the planetary carrier c1 and the ring gear r1 are supported by bearings 18 in a rotatable manner.

[0074] Furthermore, the two parallel and horizontally arranged intermediate shafts 19 and 20 are rotatably supported on the side plate 4B of the frame 4 by two rows of bearings 21 and 22, respectively. At the two axial ends of the lower intermediate shaft 20 (inner and outer sides of the side plate 4B of the frame 4), intermediate gears 23 and 24 of different diameters are respectively connected. Moreover, one intermediate gear 23 meshes with a gear 25 engraved on the outer circumference of one axial end of the gear ring r1.

[0075] On the other hand, an end drive gear 26 is connected to one axial end of the upper intermediate shaft 19 (the portion protruding to the outside of the side plate 4B of the frame 4). The end drive gear 26 meshes with the intermediate gear 24, which has a smaller diameter, and with the crown wheel 2, which has a larger diameter. Here, the two intermediate gears 23 and 24 and the end drive gear 26 constitute a gear train that transmits the rotation of the gear ring r1 to the crown wheel 2, via which the gear ring r1 meshes with the crown wheel 2. Alternatively, the crown wheel 2 and the end drive gear 26 can also be meshed by bevel gears.

[0076] Furthermore, the above only applies to one side ( Figure 2 The gear train on the left side was explained, while the other side ( Figure 2 The gear train on the right side has the same structure as the gear train on the other side, so the elements constituting the gear train are marked with the same symbol and the reiteration of their equality is omitted.

[0077] In the drive unit 1 configured as described above, the pair of first electric motor M1 and second electric motor M2, the pair of first planetary gear mechanism G1 and second planetary gear mechanism G2, and the gear system (intermediate gears 23, 24 and end transmission gear 26) are symmetrically arranged on both sides of the wheel 9. Figure 2 (left and right).

[0078] Here, the structure of the drive system of drive unit 1 in this embodiment is schematically shown. Figure 4 In this figure, gear rings r1 and r2 each include two intermediate gears 23 and 24 and one end drive gear 26. For convenience, these gear rings r1 and r2 are shown in the form of direct meshing with crown gear 2.

[0079] In addition, the drive unit 1 of the present invention includes an electronic control unit (ECU) 30 as a control element, which controls the rotation direction and speed of the first motor M1 and the second motor M2, and the ECU 30 is electrically connected to the first motor M1 and the second motor M2.

[0080] Here, as Figure 4As shown, if the angular velocity of the first motor M1 is set to ω1, the angular velocity of the second motor M2 is set to ω2, the angular velocity of the planet carrier c1 of the first planetary gear mechanism G1 is set to ω3, the angular velocity of the planet carrier c2 of the second planetary gear mechanism G2 is set to ω4, the angular velocity of the ring gear r1 of the first planetary gear mechanism G1 is set to ω5, the angular velocity of the ring gear r2 of the second planetary gear mechanism G2 is set to ω6, the turning angular velocity of the wheel 9 is set to ω7, the gear ratio of the sun gears s1 and s2 relative to the ring gears r1 and r2 is set to ξ, and the gear ratio of the ring gears r1 and r2 relative to the crown gear 2 is set to ε, then the following equation holds true. Furthermore, as... Figure 4 As shown, set the + direction of the arrow on wheel axle 8 to forward rotation and the - direction to reverse rotation.

[0081] ω1=(1+ξ)ω3-ξω5···(1)

[0082] ω2=(1+ξ)ω4-ξω6···(2)

[0083] Here, the planet carrier c1 of the first planetary gear mechanism G1 and the planet carrier c2 of the second planetary gear mechanism G2 are both connected to the wheel axle 8, so their angular velocities ω3 and ω4 are always equal. Therefore, the following equation holds true.

[0084] ω3=ω4···(3)

[0085] Therefore, based on equations (1) to (3) above, the following equation is derived.

[0086] ω1-ω2=ξ(ω6-ω5)···(4)

[0087] In addition, in order for the frame 4 to rotate around the spindle 3 and for the wheel 9 (unmanned transport vehicle) to turn, the angular velocity ω5 of the gear ring r1 of the first planetary gear mechanism G1 and the angular velocity ω6 of the gear ring r2 of the second planetary gear mechanism G2 must be opposite in direction and equal in absolute value. The following equation holds between their equality and the turning angular velocity ω7 of the wheel 9.

[0088] -ω5=ω6=εω7···(5)

[0089] Next, refer to the following side. Figure 4 and Figure 5 The operation of the drive unit 1 of the present invention will be described in terms of the following scenarios: the unmanned transport vehicle travels in a straight line, it travels in a turn, and it only turns (turns while stationary).

[0090] 1) When driving in a straight line:

[0091] When the unmanned transport vehicle is traveling in a straight line, the ECU 30 drives the first motor M1 and the second motor M2 to rotate in the same direction (forward or reverse) at the same speed. Thus, the rotation of the first motor M1 and the second motor M2 is transmitted from the sun gears s1 and s2 of the first planetary gear mechanism G1 and the second planetary gear mechanism G2 through the planetary gears p1 and p2 and the planet carriers c1 and c2 to the axle 8, and from the ring gears r1 and r2 to the crown gear 2. Here, the ring gears r1 and r2 want to rotate in the same direction, and when these ring gears r1 and r2 rotate in the same direction at the same speed, the rotation of the crown gear 2 is locked, and the turning angular velocity ω7 of the wheel 9 relative to the crown gear 2 is as follows: Figure 5 The value shown is 0 (ω7 = 0).

[0092] As described above, when the rotation of crown wheel 2 is locked, the rotation of gear rings r1 and r2 meshing with crown wheel 2 is also locked, as according to... Figure 5 As clearly stated in equation (5), the angular velocities ω5 and ω6 of the gear rings r1 and r2 are both 0 (ω5 = ω6 = 0).

[0093] Therefore, both the first planetary gear mechanism G1 and the second planetary gear mechanism G2 function as reduction mechanisms. The planetary gears p1 and p2, which rotate on their own axes 16 and revolve around the sun gears s1 and s2 simultaneously, and the planet carriers c1 and c2 supporting these planetary gears p1 and p2, rotate in a reduced-speed state, driven by the driving force input from the sun gears s1 and s2. Thus, when the planet carriers c1 and c2 rotate, the axle 8 and wheels 9 connecting them rotate, allowing the unmanned transport vehicle to travel in a straight line (forward or backward).

[0094] Here, as Figure 5 As shown, the angular velocity ω1 of the first motor M1 and the angular velocity ω2 of the second motor M2 are both 100 (relative values, not absolute actual values ​​in rad / sec). Assuming a gear ratio ξ = 4 and ε = 5, the angular velocity ω3 of the planet carrier c1 of the first planetary gear mechanism G1 and the angular velocity ω4 of the planet carrier c2 of the second planetary gear mechanism G2 are obtained according to equations (1) and (2). Figure 5 As shown, ω3 = ω4 = 20. That is, the speed of the first motor M1 and the second motor M2 is reduced to 1 / 5 (the torque is amplified to 5 times) and transmitted to the axle 8 and the wheel 9.

[0095] 2) When turning:

[0096] When the unmanned transport vehicle is turning, the ECU 30 drives the first motor M1 and the second motor M2 to rotate in the same direction with a speed difference. Thus, as in straight-line driving, the rotation of the first motor M1 and the second motor M2 is transmitted from the sun gears s1 and s2 of the first planetary gear mechanism G1 and the second planetary gear mechanism G2 through the planetary gears p1 and p2 and the planet carriers c1 and c2 to the axle 8, and from the ring gears r1 and r2 to the crown gear 2. Here, as... Figure 5 As shown, when the angular velocity ω1 of the first motor M1 is 120 and the angular velocity ω2 of the second motor M2 is 80, the angular velocity ω3 of the planet carrier c1 of the first planetary gear mechanism G1 connected to the wheel axle 8 is equal to the angular velocity ω4 of the planet carrier c2 of the second planetary gear mechanism G2 as shown in equation (3) (ω3=ω4). As in straight-line travel, ω3=ω4=20 (refer to...). Figure 5 In this configuration, the ring gear r1 of the first planetary gear mechanism G1 and the ring gear r2 of the second planetary gear mechanism G2 rotate in opposite directions with angular velocities ω5 and ω6, respectively. Relative to the crown wheel 2 meshing with these ring gears r1 and r2, the frame 4 and the wheel 9 supported thereon rotate in the horizontal plane with an angular velocity ω7, centered on the spindle 3. Thus, the wheel 9 rotates with an angular velocity ω7 around the spindle 3, enabling the unmanned transport vehicle to turn.

[0097] Here, if we use equations (1) and (2) to calculate the angular velocity ω5 of the gear ring r1 of the first planetary gear mechanism G1 and the angular velocity ω6 of the gear ring r2 of the second planetary gear mechanism G2, then as follows Figure 5 As shown, ω5 = -5 and ω6 = 5. Furthermore, if we use equation (5) to calculate the turning speed ω7 of wheel 9, then as shown... Figure 5 As shown, ω7=1.

[0098] 3) The case of turning only:

[0099] When the unmanned transport vehicle turns on the spot while already stopped, the ECU 30 rotates in the opposite direction at the same speed, driving the first motor M1 and the second motor M2 respectively. In this case, as... Figure 5As shown, the angular velocity ω3 of the planet carrier c1 of the first planetary gear mechanism G1 and the angular velocity ω4 of the planet carrier c2 of the second planetary gear mechanism G2, which are directly connected to the axle 8, are both 0 (ω3=ω4=0). Therefore, in this state, the planetary gear p1 of the first planetary gear mechanism G1 and the planetary gear p2 of the second planetary gear mechanism G2 rotate on their own axes instead of revolving around the sun gears s1 and s2, causing the gear rings r1 and r2 to rotate in opposite directions with angular velocities ω5 and ω6, respectively. As a result, the frame 4 and the axle 8 and wheel 9 supported on it rotate horizontally with an angular velocity ω7 around the spindle 3. Thus, the wheel 9 rotates around the spindle 3, thereby causing the unmanned transport vehicle to turn on the spot with an angular velocity ω7.

[0100] At this time, as Figure 5 As shown, when the first motor M1 is driven by rotation with an angular velocity ω1 = 20 and the second motor M2 is driven by rotation with an angular velocity ω2 = -20, the angular velocity ω5 of the gear ring r1 of the first planetary gear mechanism G1 and the angular velocity ω6 of the gear ring r2 of the second planetary gear mechanism G2 are calculated according to equations (1) and (2) in the following ways.

[0101] ω5=-ω1 / ξ=-20 / 4=-5

[0102] ω6=-ω1 / ξ=20 / 4=5

[0103] In addition, the turning angular velocity ω7 of wheel 9 is calculated according to equation (5) in the following manner.

[0104] ω7=-ω5 / ε=ω6 / ε=5 / 5=1

[0105] As clearly stated in the above description, according to the drive unit 1 of the present invention, the driving force of the pair of first motors M1 and second motors M2 is used for both the driving and turning of the unmanned transport vehicle. Therefore, the driving force required for these first motors M1 and second motors M2 can be smaller, thereby achieving miniaturization and energy saving of these first motors M1 and second motors M2. As a result, the energy-saving and miniaturized / compacted effects of the drive unit 1 are achieved.

[0106] [Second Invention]

[0107] Next, according to Figures 6-9 The second invention will be described.

[0108] Figure 6 A perspective view of the drive unit of the unmanned transport vehicle of the second invention. Figure 7 This is a longitudinal cross-sectional view of the drive unit. Figure 8 A diagram illustrating the structure of the drive system of the drive unit. Figure 9This is a table showing the angular velocity values ​​of each rotational element of the drive unit and the on / off state of the brake. Figures 6-8 In the middle, to and Figures 1-4 The same elements shown in the previous section are labeled with the same symbol, and further explanation of their equivalents will be omitted below.

[0109] like Figure 6 and Figure 7 As shown, the drive unit 1A of the present invention is configured in such a way that at one end of the axial direction of the axle 8 ( Figure 2 The motor M and planetary gear mechanism G are configured at the left end of the axle 8, and at the other axial end of the axle 8. Figure 2 The first brake Br1 is disposed at the right end of the spindle 3, and the second brake Br2 is installed at the lower end of the spindle 3. Furthermore, other structures, including the gear system, are the same as in the first invention. Alternatively, the end drive gear 26 and the crown wheel 2 can be meshed by bevel gears, which is the same as in the first invention.

[0110] The structure of the electric motor M is the same as that of the first motor M1 and the second motor M2 of the first invention, and the structure of the planetary gear mechanism G is also the same as that of the first planetary gear mechanism G1 and the second planetary gear mechanism G2 of the first invention. That is, the motor M is constructed by housing the stator 12 and the rotor 13 inside the motor housing 11, and the planetary gear mechanism G is constructed by including the sun gear s, the ring gear r, multiple (three) planetary gears p, and the planet carrier c.

[0111] Furthermore, both the first brake Br1 and the second brake Br2 include electromagnetic brakes. The first brake Br1 performs the following functions: locking the rotation of the axle 8 (wheel 9) by connecting, and releasing the locking of the rotation of the axle 8 (wheel 9) by disconnecting. The brake Br2 performs the following functions: locking the turning of the wheel 9 by connecting, and releasing the locking of the turning of the wheel 9 by disconnecting.

[0112] Here, the structure of the drive system of the drive unit 1A of the present invention is schematically shown. Figure 8 In this diagram, with Figure 4 Similarly, the gear ring r also includes two intermediate gears 23 and 24 and a final drive gear 26. For convenience, the gear ring r is also illustrated in the form of direct meshing with the crown gear 2.

[0113] Furthermore, the drive unit 1A of the present invention includes an ECU 30 as a control element, which controls the rotational speed of the motor M and the on / off state of the first brake Br1 and the second brake Br2. The ECU 30 is electrically connected to the motor M and the first brake Br1 and the second brake Br2.

[0114] Here, as Figure 8As shown, if the angular velocity of motor M is set to ω1, the angular velocity of the planet carrier c of planetary gear mechanism G is set to ω3, the angular velocity of ring gear r is set to ω5, the turning angular velocity of wheel 9 is set to ω7, the gear ratio of sun gear s to ring gear r is set to ξ, and the gear ratio of ring gear r to crown gear 2 is set to ε, then the following equation holds true. Furthermore, as... Figure 8 As shown, set the + direction of the arrow on wheel axle 8 to forward rotation and the - direction to reverse rotation.

[0115] ω1=(1+ξ)ω3-ξω5···(6)

[0116] Here, when the first brake Br1 is turned on and the rotation of the wheel axle 8 (wheel 9) is locked, the angular velocity ω3 of the planet carrier c of the planetary gear mechanism G is 0, so equation (6) is expressed as follows.

[0117] ω1=-ξω5=-ξεω7···(7)

[0118] Furthermore, when the second brake Br2 is turned on and the rotation of the gear ring r is locked, the angular velocity of the gear ring r is ω5 = 0, so equation (6) is expressed as follows.

[0119] ω1=(1+ξ)ω3···(8)

[0120] Next, refer to the following side. Figure 8 and Figure 9 The operation of the drive unit 1A of the present invention will be described in terms of the unmanned transport vehicle traveling in a straight line, traveling in a turning direction, and only turning (turning while stationary).

[0121] 1) When driving in a straight line:

[0122] When the unmanned transport vehicle travels in a straight line, such as Figure 9 As shown, ECU 30 rotates drive motor M at a predetermined speed while the first brake Br1 is disengaged and the second brake Br2 is engaged, thus locking the turning of wheel 9 and the rotation of the ring gear r of planetary gear mechanism G. The rotation of motor M is then transmitted from the sun gear s of planetary gear mechanism G through planetary gear p and planet carrier c to axle 8, which, along with the wheel 9 connected thereto, rotates, thereby enabling the unmanned transport vehicle to travel in a straight line (forward or backward).

[0123] Here, the angular velocity ω1 of motor M is as follows: Figure 9 As shown in the figure, 100, under the assumption that the gear ratio ξ = 4 and ε = 5, the angular velocity ω3 of the planet carrier c of the planetary gear mechanism G is obtained in the following manner according to equation (8).

[0124] ω3=ω1 / (1+ξ)=100 / 5=20

[0125] Therefore, the speed of motor M is reduced to 1 / 5 (the torque is amplified to 5 times) and transmitted to axle 8 and wheel 9.

[0126] 2) When turning:

[0127] When the unmanned delivery vehicle turns, such as Figure 9 As shown, ECU 30 disengages both the first brake Br1 and the second brake Br2, and rotates the drive motor M at a predetermined speed. Thus, the rotation of motor M is transmitted from the sun gear s of the planetary gear mechanism G through the planetary gears p and planet carrier c to the axle 8, and from the ring gear r to the crown gear 2. Here, as... Figure 9 As shown, the angular velocity ω1 of the motor M is 120°, and the angular velocity ω3 of the planetary carrier c connected to the wheel axle 8 of the planetary gear mechanism G is ω3 = 20°. In this case, the ring gear r of the planetary gear mechanism G rotates at an angular velocity ω5, and relative to the crown wheel 2 meshing with the ring gear r, the frame 4 and the wheel 9 supported thereon rotate in the horizontal plane with an angular velocity ω7 about the spindle 3. Thus, the wheel 9 rotates with an angular velocity ω7 about the spindle 3, thereby enabling the unmanned transport vehicle to turn.

[0128] Here, if we use equation (6) to calculate the angular velocity ω5 of the gear ring r of the planetary gear mechanism G, then as follows Figure 9 As shown, ω5=-5.

[0129] ω5=((1+ξ)ω3-ω1) / ξ

[0130] = (5 × 20 - 120) / 4 = -5

[0131] (Refer to Figure 9 ).

[0132] Furthermore, if we use equation (7) to calculate the turning angular velocity ω7 of wheel 9, then

[0133] ω7=ω5 / ε=-5 / 5=-1

[0134] (Refer to Figure 9 ).

[0135] 3) The case of turning only:

[0136] When the unmanned transport vehicle makes a turn while stationary, ECU 30 engages the first brake Br1 and disengages the second brake Br2, rotating the drive motor M at a predetermined speed. In this situation, the rotation of axle 8 (wheel 9) is locked, therefore the rotation of the planetary carrier c of the planetary gear mechanism G, which is connected to axle 8, is also locked. Figure 9As shown, the angular velocity ω3 of the planetary carrier c is 0 (ω3=0). Therefore, in this state, the planetary gear p of the planetary gear mechanism G rotates on its own axis instead of revolving around the sun gear s, causing the ring gear r to rotate at an angular velocity ω5. As a result, the frame 4 and the axle 8 and wheel 9 supported thereon rotate horizontally about the spindle 3 at an angular velocity ω7. Thus, the wheel 9 rotates about the spindle 3, thereby causing the unmanned transport vehicle to turn on the spot at an angular velocity ω7.

[0137] At this time, as Figure 9 As shown, when the motor M is driven by rotation at an angular velocity ω1=100, the angular velocity ω5 of the gear ring r of the planetary gear mechanism G is calculated in the following manner according to equation (7).

[0138] ω5=-ω1 / ξ=-100 / 4=-25

[0139] In addition, the turning angular velocity ω7 of wheel 9 is calculated according to equation (7) in the following manner (refer to...). Figure 9 ).

[0140] ω7=ω5 / ε=-25 / 5=-5

[0141] As clearly stated in the above description, according to the drive unit 1A of the present invention, the unmanned transport vehicle is driven by the driving force of a motor M, so the motor M can be further miniaturized and energy-saving, thereby achieving the effect of further energy saving and miniaturization and compactness of the drive unit 1A.

[0142] Furthermore, the application of this invention is not limited to the embodiments described above, and various modifications can be made within the scope of the technical concept described in the claims, specification and drawings.

Claims

1. A drive unit for an unmanned transport vehicle, comprising: A turning gear is fixed to the bottom of the vehicle body; a spindle extends vertically from the vehicle body through the center of the turning gear. The drive unit of the unmanned transport vehicle is characterized by the following configuration: a frame supported on the spindle in a manner that allows it to rotate in a horizontal plane; an axle rotatably mounted on the frame; and wheels connected to the axle. A first motor and a second motor, serving as drive sources, a first planetary gear mechanism, and a second planetary gear mechanism are respectively configured at both ends of the axial direction of the axle. The planet carriers of the first and second planetary gear mechanisms are respectively connected to the axle, and the ring gears of the first and second planetary gear mechanisms respectively mesh with the turning gear. The wheels are driven to move by making the first motor and the second motor rotate at the same speed, and the wheels are driven to turn by setting a rotation difference between the first motor and the second motor. The driving force of the first motor and the second motor is used for both the movement and turning of the unmanned transport vehicle.

2. The drive unit of the unmanned transport vehicle according to claim 1, characterized in that, Each of the gear rings meshes with the turning gear via multiple gear systems.

3. The drive unit of the unmanned transport vehicle according to claim 2, characterized in that, The first motor and the second motor pair, the first planetary gear mechanism and the second planetary gear mechanism pair, and each of the gear systems are symmetrically arranged on both sides of the wheel.

4. The drive unit of the unmanned transport vehicle according to any one of claims 1 to 3, characterized in that, It includes a control element that controls the rotational direction and speed of the first motor and the second motor. When the unmanned transport vehicle is traveling in a straight line, the control element drives the first motor and the second motor to rotate in the same direction and at the same speed. When the unmanned transport vehicle turns, the control element rotates in the same direction, driving the first motor and the second motor with a predetermined speed difference. When the unmanned transport vehicle is only turning, the control elements rotate in opposite directions at the same speed, driving the first motor and the second motor.

5. A drive unit for an unmanned transport vehicle, comprising: A turning gear is fixed to the bottom of the vehicle body; a spindle extends vertically from the vehicle body through the center of the turning gear. The drive unit of the unmanned transport vehicle is characterized by the following configuration: a frame supported on the spindle in a manner that allows it to rotate in a horizontal plane; an axle rotatably mounted on the frame; and wheels connected to the axle. A motor and planetary gear mechanism, serving as a drive source, are configured at one axial end of the axle; a first brake is mounted at the other axial end of the axle; and a second brake is mounted on the spindle. The planet carrier of the planetary gear mechanism is connected to the axle, and the ring gear of the planetary gear mechanism meshes with the turning gear. By switching the engagement and release combinations of the first brake and the second brake, the driving force of the motor is selectively switched and made to act as: a driving force generated by the rotation of the wheel and a turning force generated by the rotation of the frame around the spindle.

6. The drive unit of the unmanned transport vehicle according to claim 5, characterized in that, The gear ring meshes with the turning gear via multiple gear trains.

7. The drive unit of the unmanned transport vehicle according to claim 5 or 6, characterized in that, It includes a control element that controls the rotation direction and speed of the motor, as well as the on / off state of the first and second brakes. When the unmanned transport vehicle is traveling in a straight line, the control element drives the motor at a predetermined speed while the first brake is disengaged and the second brake is engaged. When the unmanned transport vehicle turns, the control element drives the motor at a predetermined speed while both the first brake and the second brake are disengaged. When the unmanned transport vehicle is only turning, the control element drives the motor at a predetermined speed while the first brake is engaged and the second brake is disengaged.

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