Electric drive system
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-06-04
- Publication Date
- 2026-08-14
Smart Images
Figure 2026131773000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an electric drive device.
Background Art
[0002] Conventionally, as described in Patent Document 1, a transmission integrated with a motor is known.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] The transmission includes an input shaft, an output shaft extending in the direction in which the input shaft extends, and a transmission mechanism that changes the rotational speed of the input shaft and transmits it to the output shaft. The input shaft, the output shaft, and the transmission mechanism are housed in a case of the transmission.
[0005] There may be a requirement for a braking mechanism that applies a braking force to the input shaft of the transmission. If the transmission is provided with a braking mechanism, there is a concern that the size of the transmission will increase.
[0006] The main object of the present invention is to provide an electric drive device that can suppress an increase in size as much as possible.
Means for Solving the Problems
[0007] The present invention is an electric drive device mounted on a vehicle, including an input shaft, an output shaft that extends in the direction in which the input shaft extends and rotates a drive wheel of the vehicle, a transmission mechanism that changes the rotational speed of the input shaft and transmits it to the output shaft, a case that houses the input shaft, the output shaft, and the transmission mechanism, and a braking mechanism that applies a braking torque to the input shaft. A motor that applies rotational torque to the input shaft of the transmission, A control board is provided, The control board controls the motor in order to apply rotational torque to the input shaft, based on commands from a higher-level ECU to the control board. The braking mechanism is energized by a command from the higher-level ECU, thereby stopping the application of the braking torque while the motor is being controlled by the control board, and then reapplies the braking torque when the power supply is stopped.
[0008] This makes it possible to minimize the increase in size of the electric drive unit equipped with a transmission. [Brief explanation of the drawing]
[0009] [Figure 1] A diagram showing the overall configuration of an automated guided vehicle according to one embodiment. [Figure 2] Side view of an automated guided vehicle (AGV). [Figure 3] Perspective view of the speed reduction gear. [Figure 4] A diagram showing the internal structure of the motor and reduction gear. [Figure 5] A diagram showing the internal configuration of the speed reducer with the second and third case members removed. [Figure 6] A diagram showing the internal configuration of the reduction gear with the third case component removed. [Figure 7] A diagram showing the internal configuration of the reduction gear with the third case component removed. [Figure 8] A diagram showing the drum brake mechanism. [Figure 9] A diagram showing the drum brake mechanism in the brake operating state. [Figure 10] A diagram showing a drum brake mechanism in a non-operated state. [Figure 11] A view from above of the solenoid coil area inside the case. [Figure 12] A diagram showing the overall configuration of an automated guided vehicle according to another embodiment. [Figure 13] Side view of an automated guided vehicle according to another embodiment. [Modes for carrying out the invention]
[0010] Hereinafter, an embodiment of the transmission and electric drive system equipped with the transmission according to the present invention will be described with reference to the drawings. The electric drive system is applied to small mobility vehicles. The small mobility vehicle of this embodiment is a vehicle that travels at a low speed, for example, 10 km / h or less. Specifically, the small mobility vehicle is an unmanned guided vehicle (AGV) that is an electric vehicle used for transporting goods in a factory production line or a workplace such as a warehouse, and more specifically, it is an AGV (Automatic Guided Vehicle).
[0011] As shown in Figures 1 and 2, the automated guided vehicle (AGV) 10 comprises a vehicle body 11 and a plurality of drive wheels 12. In this embodiment, the plurality of drive wheels 12 are the right front wheel 12FR, the left front wheel 12FL which is aligned with the right front wheel 12FR in the vehicle width direction, the right rear wheel 12RR, and the left rear wheel 12RL which is aligned with the right rear wheel 12RR in the vehicle width direction. In other words, the AGV 10 is equipped with two sets of right drive wheels and two sets of left drive wheels. Note that, for convenience, only the configuration of the right drive wheels is shown in Figure 2.
[0012] The vehicle body 11 has a structure in which the length dimension is greater than the width dimension. The top surface of the vehicle body 11 is a loading surface 11a on which the transported object is placed. The loading surface 11a is approximately parallel to the road surface GL of the automated guided vehicle 10. In Figure 1, the outer edge of the vehicle body 11 is drawn with a dashed line, and a portion of the structure below the loading surface 11a of the vehicle body 11 is drawn with a solid line.
[0013] The vehicle body 11 is equipped with, as an in-vehicle system, an electric drive device 20 for rotating drive wheels 12 to run the driverless transport vehicle 10, a steering mechanism 13 for steering the drive wheels 12, a host ECU (not shown) for controlling the running of the driverless transport vehicle 10, and a power storage unit (not shown) that serves as the power source for the electric drive device 20 and the host ECU. The power storage unit is, for example, a secondary battery such as a lithium-ion battery. The power storage unit is provided, for example, at the lower part of the vehicle body 11.
[0014] The electric drive devices 20 are provided individually corresponding to the respective drive wheels 12. In the present embodiment, the electric drive devices 20 basically have the same configuration. The electric drive device 20 includes a motor 30 that serves as the rotational power source of the drive wheel 12, and a speed reduction device 50 that amplifies the output torque of the motor 30 and transmits it to the drive wheel 12.
[0015] First, the motor 30 will be described using FIG. 4. FIG. 4 is a longitudinal full view of the motor 30 and the speed reduction device 50.
[0016] The motor 30 includes a rotor 31 including a field pole (for example, a permanent magnet), a shaft 32 fixed to the rotor 31, and a stator 33 disposed to face the outside in the radial direction with respect to the rotor 31. The rotation center axis of the shaft 32 extends in the horizontal direction. The stator 33 includes a stator core (not shown) and a stator winding (not shown) wound around the stator core.
[0017] The motor 30 includes a motor housing 34. The motor housing 34 includes a tubular section 35, a first connecting section 36, a second connecting section 37, and a cover section 38. The tubular section 35 is long in the direction in which the shaft 32 extends, and is specifically cylindrical. The first connecting section 36 is provided at the first end of the tubular section 35 in the longitudinal direction, and the second connecting section 37 is provided at the second end. The rotor 31 and stator 33 are housed in the cylindrical space enclosed by the tubular section 35, the first connecting section 36, and the second connecting section 37. The stator 33 is provided on the inner circumferential surface of the tubular section 35. Note that the motor housing 34 is not limited to having a cylindrical cross-section; for example, it may have a rectangular cross-section.
[0018] A first opening 36a is formed in the first connecting portion 36. A first motor bearing 39 is provided in the first opening 36a. A second opening 37a is formed in the second connecting portion 37, and a second motor bearing 40 is provided in the second opening 37a. In this embodiment, each bearing 39, 40 is a rolling bearing having an inner ring, an outer ring, and rolling elements provided between the inner ring and the outer ring. The first end of the shaft 32 is rotatably supported by the first motor bearing 39, and the second end of the shaft 32 is rotatably supported by the second motor bearing 40.
[0019] A cover portion 38 is provided on the side of the second connection portion 37 opposite to the tubular portion 35 in the longitudinal direction of the motor housing 34. A control board 41 is arranged in the space enclosed by the second connection portion 37 and the cover portion 38. In this embodiment, the control board 41 is positioned so that its surface is perpendicular to the direction in which the shaft 32 extends. The control board 41 is equipped with an inverter electrically connected to the stator winding and a motor ECU as a control unit. The inverter has three phases of semiconductor switches on the upper and lower arms. The inverter converts the DC power supplied from the power storage unit of the automated guided vehicle 10 into AC power by switching control of the semiconductor switches on the upper and lower arms and supplies it to the stator winding. The motor ECU is mainly composed of a microcontroller. The motor ECU performs switching control of the inverter in order to control the control amount (e.g., torque) of the motor 30 to a command value transmitted from the higher-level ECU.
[0020] Next, the reduction gear 50 will be described using Figures 3 to 5. For convenience, some of the components of the case and other parts shown in Figure 4 are simplified versions of those shown in Figure 3. The reduction gear 50 amplifies the input torque from the shaft 32 and outputs it to the drive wheels 12. In this embodiment, in order to suppress the increase in the size of the electric drive unit 20 in the vehicle width direction, the reduction gear 50 has a configuration that is long in the vehicle length direction. The reduction gear 50 includes a case 60 connected to the motor housing 34.
[0021] The case 60 has a roughly rectangular parallelepiped shape with its longitudinal direction perpendicular to the input shaft 70b and the output shaft 72b. The case 60 comprises a roughly rectangular bottom plate 66, first and second longitudinal wall portions 67a and 67b extending perpendicularly from the long side of the bottom plate 66, first and second short-side wall portions 68a and 68b extending perpendicularly from the short side of the bottom plate 66, and a top plate 69. The case 60 is composed of a first case member 61, a second case member 62, and a third case member 63. The output shaft 72b extends outside the case 60 from an output-side opening formed in the first longitudinal wall portion 67a of the case 60. The input shaft 70b extends toward an opening 63a (corresponding to the "input-side opening") formed in the second longitudinal wall portion 67b of the case 60. Figure 5 shows the internal configuration of the reduction gear 50 with the second and third case members 62 and 63 removed. For convenience, some components are omitted from the illustration in Figure 5.
[0022] The first space 64, enclosed by the first case member 61 and the second case member 62, houses a plurality of spur gears that constitute a reduction (speed change) mechanism. Specifically, the first space 64 houses an input gear 70a, an intermediate gear 71a, and an output gear 72a arranged in the longitudinal direction of the case 60. The input gear 70a is provided with an input shaft 70b, the intermediate gear 71a is provided with an intermediate shaft 71b, and the output gear 72a is provided with an output shaft 72b. The input shaft 70b, the intermediate shaft 71b, and the output shaft 72b extend in the same direction as the shaft 32. In this embodiment, the rotational axes of the input shaft 70b, the intermediate shaft 71b, the output shaft 72b, and the shaft 32 are located on the same plane.
[0023] An opening 63a is formed in the third case member 63. A shaft 32 is inserted through the opening 63a. The first end of the shaft 32 is fixed to the first end of the input shaft 70b by a joint or the like. The second end of the input shaft 70b is rotatably supported by a first bearing 70c (rolling bearing) provided in the first longitudinal wall portion 67a.
[0024] The intermediate shaft 71b of the intermediate gear 71a that meshes with the input gear 70a is rotatably supported by a second bearing 71c (rolling bearing) provided on the first and second longitudinal walls 67a and 67b. The output shaft 72b of the output gear 72a that meshes with the intermediate gear 71a is rotatably supported by a third bearing 72c (rolling bearing) provided on the first and second longitudinal walls 67a and 67b. The output shaft 72b extends to the outside of the case 60 through an output-side opening in the first longitudinal wall 67a where the third bearing 72c is provided. A drive wheel 12 is connected to the end of the output shaft 72b.
[0025] The diameter of the intermediate gear 71a is larger than the diameter of the input gear 70a, and the diameter of the output gear 72a is larger than the diameter of the intermediate gear 71a. In other words, the diameters of each gear 70a, 71a, and 72a housed in the first space 64 increase in the longitudinal direction of the case 60 from the input shaft 70b side to the output shaft 72b side. This reduces the rotational speed of the output gear 72a relative to the input gear 70a, making it possible to amplify the torque transmitted from the motor 30 to the input shaft 70b and transmit it to the output shaft 72b.
[0026] Returning to the explanation of Figures 1 and 2, each electric drive unit 20 is arranged such that the longitudinal direction of the case 60 constituting the reduction gear 50 faces the vehicle length direction. In addition, each electric drive unit 20 arranged in the vehicle width direction is arranged such that each output shaft 72b is aligned in the vehicle width direction.
[0027] As shown in Figure 2, the upper part of the case 60 of each electric drive unit 20 is connected to the lower part of the vehicle body 11 via a steering mechanism 13. The steering mechanism 13 rotatably supports the electric drive unit 20 relative to the vehicle body 11 around an axis perpendicular to the mounting surface 11a. This enables steering of the drive wheels 12. Steering by the steering mechanism 13 is performed, for example, by a higher-level ECU.
[0028] In the example shown in Figure 1, the motor 30 of the electric drive unit 20 corresponding to the right front wheel 12FR (corresponding to the "right side unit") and the motor 30 of the electric drive unit 20 corresponding to the left front wheel 12FL (corresponding to the "left side unit") are facing each other in the vehicle length direction. Similarly, the motor 30 of the electric drive unit 20 corresponding to the right rear wheel 12RR (corresponding to the "right side unit") and the motor 30 of the electric drive unit 20 corresponding to the left rear wheel 12RL (corresponding to the "left side unit") are facing each other in the vehicle length direction. This reduces the width dimension of the automated guided vehicle 10. Furthermore, each electric drive unit 20 is positioned so that its top plate portion 69 faces upward.
[0029] Each electric drive unit 20 is equipped with a brake mechanism 80 that applies braking to the drive wheels 12. The brake mechanism 80 will be described below with reference to Figures 4 to 8. Figures 6 and 7 show the internal configuration of the reduction gear 50 with the third case member 63 removed. In Figures 6 and 7, some components are omitted from the illustration for convenience.
[0030] In this embodiment, the brake mechanism 80 applies braking torque only to the input shaft 70b of the input shaft 70b and output shaft 72b. The torque of the output shaft 72b is greater than the torque of the input shaft 70b. For this reason, brake mechanisms that apply braking torque to the output shaft 72b tend to be large. In contrast, the brake mechanism 80 of this embodiment can be made smaller.
[0031] The brake mechanism 80 is a drum brake mechanism and includes a brake drum 81 (corresponding to the "rotating part") provided on the input shaft 70b. The brake drum 81 is housed in a second space 65 surrounded by a second case member 62 and a third case member 63, and rotates integrally with the input shaft 70b. Because the brake mechanism 80 is housed in the case 60, the size of the reduction gear 50 can be kept from increasing.
[0032] A fixing portion 73 for securing the brake drum 81 is provided on the input shaft 70b on the motor 30 side of the input gear 70a. The brake drum 81 comprises a disc portion 81a fixed to the fixing portion 73 by fastening members such as bolts, and a sliding portion 81b. The sliding portion 81b is an annular shape that extends from the peripheral edge of the disc portion 81a toward the input gear 70a in the direction in which the input shaft 70b extends. The brake drum 81 rotates integrally with the input shaft 70b. Figures 6 and 7 show the brake drum 81 in a state with the brake drum 81 removed.
[0033] As shown in Figures 4, 6, and 7, the brake mechanism 80 includes a first brake shoe 82 and a second brake shoe 83. The first brake shoe 82 faces the inner circumferential surface of the sliding portion 81b of the brake drum 81 and has an arc shape extending along this inner circumferential surface. The second brake shoe 83 faces the inner circumferential surface of the sliding portion 81b that is opposite to the surface facing the input shaft 70b where the first brake shoe 82 faces, and has an arc shape extending along this inner circumferential surface.
[0034] The brake mechanism 80 includes an anchor portion 84 and a return spring 85 as a biasing portion (see Figure 8). Figure 8 is a view of the brake mechanism 80 shown in Figure 7 from the rear. The anchor portion 84 is a member that supports the first ends of the first brake shoe 82 and the second brake shoe 83 so that they can rotate relative to the case 60 around the direction in which the input shaft 70b extends. The anchor portion 84 is fixed to the case 60 (for example, the first longitudinal wall portion 67a of the first case member 61).
[0035] The return spring 85 is attached to each brake shoe 82, 83 and is a component that applies elastic force to the first brake shoe 82 and the second brake shoe 83 in the direction that their respective second ends move closer together. Alternatively, a rotating spring may be attached to each brake shoe 82, 83 instead of the return spring 85. The rotating spring is provided so as to circle the anchor portion 84. In this case as well, the rotating spring applies elastic force to the first brake shoe 82 and the second brake shoe 83 in the direction that their respective second ends move closer together.
[0036] Each brake shoe 82, 83 is configured such that its first end faces its second end across the input shaft 70b.
[0037] An arc-shaped first lining 82a (corresponding to the "pressing portion") is provided on the arc-shaped portion of the first brake shoe 82 that faces the sliding portion 81b. An arc-shaped second lining 83a (corresponding to the "pressing portion") is provided on the arc-shaped portion of the second brake shoe 83 that faces the sliding portion 81b.
[0038] The brake shoes 82 and 83 are arranged such that the first end of each brake shoe 82 and 83 faces the bottom plate portion 66, and the second end of each brake shoe 82 and 83 faces the top plate portion 69. Furthermore, the brake shoes 82 and 83 are arranged such that the second end of each brake shoe 82 and 83 is located on the side of the output shaft 72b rather than the input shaft 70b in the longitudinal direction of the case 60.
[0039] The brake mechanism 80 includes a position-changing section for adjusting each lining 82a, 83a to either the state shown in Figure 6, where the second ends of the first brake shoe 82 and the second brake shoe 83 are pushed apart so that they contact the inner circumferential surface of the sliding portion 81b, or the state shown in Figure 7, where the second ends of the first brake shoe 82 and the second brake shoe 83 are brought closer together so that they are separated from the inner circumferential surface of the sliding portion 81b. Specifically, as shown in Figures 4 to 11, the position-changing section includes a cam portion 90, a solenoid coil 100, a spring 110, a base portion 111, and a lever portion 120. Note that Figure 9 corresponds to Figure 6, and Figure 10 corresponds to Figure 7.
[0040] The cam portion 90 has an oval cross-sectional shape and has a major axis direction and a minor axis direction. As shown in Figure 11, the cam portion 90 is fixed to the first end of the support portion 121 that constitutes the lever portion 120. The support portion 121 extends in the direction in which the input shaft 70b extends. The second end of the support portion 121 is supported by the first longitudinal wall portion 67a so as to be rotatable around the direction in which the input shaft 70b extends. As a result, the cam portion 90 is supported by the case 60 so as to be rotatable around the direction in which the input shaft 70b extends.
[0041] The solenoid coil 100 is a linear actuator comprising a coil section 101 (corresponding to the "main body") including a fixed iron core and a coil wound around the fixed iron core, and a movable iron core 102 (corresponding to the "movable part") that is movable in a linear direction relative to the coil section 101. As shown in Figures 4 and 11, the solenoid coil 100 is positioned within the case 60 on the side of the second short-direction wall 68b relative to the input-side gear 70a. The solenoid coil 100 is also positioned within the case 60 on the side of the first longitudinal-direction wall 67a relative to the brake drum 81.
[0042] The coil portion 101 of the solenoid coil 100 is fixed to the case 60 (for example, at least one of the bottom plate portion 66 and the second short-direction wall portion 68b). The movable core 102 is movable in the longitudinal direction of the case 60 and in a direction perpendicular to the input shaft 70b by energizing the coil portion 101. The energizing operation of the coil portion 101 is performed, for example, by the motor ECU or a higher-level ECU. When the coil portion 101 is energized, the movable core 102 is attracted by the magnetic force of the coil portion 101, and the movable core 102 moves in a direction toward the coil portion 101.
[0043] The solenoid coil 100 is equipped with wiring 103 for energizing the coil section 101. The wiring 103 is for supplying power from the energy storage section to the coil section 101. The wiring 103 is led out to the outside of the case 60 through a through hole 130 and a sealing section 131 (see Figure 3) formed in the second short-side wall section 68b of the case 60. Within the case 60, the wiring 103 is positioned in the space on the second short-side wall section 68b side of the input-side gear 70a. Therefore, the wiring 103 is less likely to get caught in rotating members such as the input-side gear 70a.
[0044] The spring 110 (for example, a compression spring) extends in the operating direction of the movable iron core 102 and is provided alongside the solenoid coil 100 in the direction in which the input shaft 70b extends. The base end of the spring 110 is attached to a base portion 111 fixed to the bottom plate portion 66.
[0045] The lever portion 120 includes a main connecting portion 122 extending longitudinally from the support portion 121 to the case 60, and a sub-connecting portion 123 branching off from the middle of the main connecting portion 122. In this embodiment, the support portion 121, the main connecting portion 122, and the sub-connecting portion 123 are integrally formed so that the lever portion 120 is configured as a single component. The tip of the main connecting portion 122 is connected to the tip of the movable core 102. In this embodiment, the connection point between the main connecting portion 122 and the movable core 102 is configured to allow rotation around the direction in which the input shaft 70b extends.
[0046] A seat portion 124 is provided on the secondary connection portion 123. The tip of the spring 110 is attached to the seat portion 124.
[0047] Next, the operating mode of the brake mechanism 80 will be described. Hereafter, the motor ECU or higher-level ECU will simply be referred to as ECU.
[0048] If the ECU determines that a braking command has been issued, it stops the power supply from the energy storage unit to the coil unit 101. As a result, the attractive force acting on the movable core 102 is eliminated, and the restoring force of the spring 110 causes the movable core 102 to move away from the coil unit 101. Consequently, the tip position of the movable core 102 is set to the first position shown in Figure 9.
[0049] As the tip position of the movable iron core 102 approaches the first position, the cam portion 90 rotates in the first direction via the lever portion 120. When the tip position of the movable iron core 102 is in the first position, the first end of the cam portion 90 in the major axis direction comes into contact with the second end of the first brake shoe 82, and the second end of the cam portion 90 in the major axis direction comes into contact with the second end of the second brake shoe 83, resulting in a first state. As a result, the first brake shoe 82 and the second brake shoe 83 are pushed apart, and the linings 82a and 83a come into contact with the inner circumferential surface of the sliding portion 81b that constitutes the brake drum 81. Consequently, braking torque is applied to the input shaft 70b.
[0050] The spring 110 provides elastic force to the lever portion 120. Here, the spring 110 is positioned alongside the solenoid coil 100 in the direction in which the input shaft 70b extends. This allows the distance between the cam portion 90 and the tip of the spring 110 to be increased, thereby increasing the amount of rotation of the cam portion 90 relative to a predetermined vertical displacement at the spring 110 side end of the lever portion 120, and enabling accurate spreading of each brake shoe 82, 83. In addition, increasing the distance between the cam portion 90 and the tip of the spring 110 allows for an increase in the moment around the main connection portion 122. Furthermore, by arranging the spring 110 in the empty space as shown in Figures 9 and 10, the free length and diameter of the spring 110 can be increased. With the above configuration, the braking torque can be increased, and for example, the stopped state of the automated guided vehicle 10 can be accurately maintained.
[0051] Furthermore, in a configuration where the spring 110 is positioned alongside the solenoid coil 100 in the direction in which the input shaft 70b extends, the vertical dimension of the solenoid coil 100 can be reduced compared to a configuration where the spring is provided on the movable iron core 102. As a result, the vertical dimension of the automated guided vehicle 10 can be reduced.
[0052] In this embodiment, in the state shown in Figure 9, the length of the spring 110 is shorter than its free length, and the spring 110 is in a compressed state. Therefore, each lining 82a, 83a can be accurately pressed against the inner circumferential surface of the sliding portion 81b.
[0053] In this embodiment, among the spur gears constituting the reduction mechanism, there is a space on the top plate portion 69 side of the input gear 70a, which has the smallest diameter. To make effective use of this space, the support portion 121 of the lever portion 120 is positioned in that space. This allows the distance between the cam portion 90 and the tip of the spring 110 to be increased, and the moment around the main connection portion 122 to be increased. As a result, the braking torque can be increased without increasing the vertical dimensions of the reduction device 50.
[0054] When the coil section 101 is not energized, a braking torque is applied to the input shaft 70b. This prevents the automated guided vehicle (AGV) 10 from starting to move when it is not in use, such as when it is stored.
[0055] On the other hand, if the ECU determines that no braking command has been issued, it energizes the coil section 101 from the energy storage unit. This causes an attractive force to act on the movable core 102, and the movable core 102 moves closer to the coil section 101 while overcoming the restoring force of the spring 110. As a result, the tip position of the movable core 102 is set to the second position shown in Figure 10.
[0056] As the tip of the movable core 102 approaches the second position, the cam portion 90 rotates in the second direction, opposite to the first direction, via the lever portion 120. When the tip of the movable core 102 is in the second position, the end of the cam portion 90 in the minor axis direction faces the second end of each brake shoe 82, 83. Due to the restoring force of the return spring 85, the first end of the cam portion 90 in the minor axis direction comes into contact with the second end of the first brake shoe 82, and the second end of the cam portion 90 in the minor axis direction comes into contact with the second end of the second brake shoe 83, resulting in a second state. As a result, the second ends of the first brake shoe 82 and the second ends of the second brake shoe 83 come closer together, and the linings 82a, 83a move away from the inner circumferential surface of the sliding portion 81b. Consequently, no braking torque is applied to the input shaft 70b.
[0057] In this embodiment, the solenoid coil 100 and spring 110, etc., necessary for the operation of each brake shoe 82, 83 are provided not between each brake shoe 82, 83, but in the space adjacent to each brake shoe 82, 83. This makes it possible to reduce the outer diameter of the brake drum 81, and consequently, to miniaturize the reduction gear 50.
[0058] In this embodiment, the vehicle body 11 is long in the vehicle length direction and short in the vehicle width direction. Therefore, it is desirable to minimize the vehicle length dimension of the reduction gear 50. To this end, a mechanism equipped with spur gears is used as the reduction mechanism, and within the case 60, the solenoid coil 100 and spring 110, etc. are arranged in the space adjacent to the input shaft 70b in the vehicle length direction. This makes it possible to reduce the vehicle width dimension of the reduction gear 50.
[0059] <Other Embodiments> The above embodiment may be implemented with the following modifications.
[0060] In the reduction mechanism, multiple intermediate gears may be provided aligned along the longitudinal direction of the case 60. In this case, the diameter of each intermediate gear may increase, for example, from the input shaft 70b side to the output shaft 72b side in the longitudinal direction of the case 60. Alternatively, the reduction mechanism may not have an intermediate gear 71a, and the input gear 70a and the output gear 72a may mesh directly with each other.
[0061] The linear actuator is not limited to a solenoid coil; for example, it may also consist of a ball screw (corresponding to the "movable part") and a motor (corresponding to the "main body") for moving the ball screw in a linear direction.
[0062] The support portion 121 that rotatably supports the cam portion 90 may be made of a separate component from the lever portion 120.
[0063] The braking mechanism is not limited to a drum brake mechanism; for example, it may be a disc brake mechanism. In this case, the braking mechanism only needs to include a disc rotor (corresponding to the "rotating part"), brake pads (corresponding to the "pressing part"), and a brake caliper (corresponding to the "position changing part"). The disc rotor is mounted on the input shaft and rotates integrally with the input shaft. The brake pads apply braking torque to the input shaft by contacting the disc rotor and stop applying braking torque to the input shaft by moving away from the disc rotor. The brake caliper, when energized, moves the brake pads either in contact with the disc rotor or away from the disc rotor.
[0064] The braking mechanism is not limited to one that applies braking torque only to the input shaft, but may also apply braking torque only to the output shaft, or apply braking torque to both the input and output shafts.
[0065] The reduction mechanism is not limited to a mechanism equipped with spur gears; for example, it may be a planetary gear mechanism or a cycloidal gear mechanism in which the rotational center axes of the input shaft and output shaft are the same.
[0066] The transmission device in an electric drive system is not limited to a reduction gear; it may also be a speed booster that increases the rotational speed of the input shaft and transmits it to the output shaft.
[0067] The motor is not limited to an inner rotor type; it may also be an outer rotor type. Furthermore, the motor is not limited to a radial gap type; it may also be an axial gap type.
[0068] • The automated guided vehicle (AGV) may be, for example, the AGV 10a shown in Figures 12 and 13. In this AGV 10a, the electric drive units 20 arranged in the vehicle width direction are positioned so that the motors 30 face each other in the vehicle width direction and the output shafts 72b are aligned in the vehicle width direction. In the example shown in Figures 12 and 13, the electric drive unit 20 that rotates the right front wheel 12FR and the left rear wheel 12RL is positioned so that the top plate portion 69 faces upward. On the other hand, the electric drive unit 20 that rotates the left front wheel 12FL and the right rear wheel 12RR is positioned so that the bottom plate portion 66 faces upward.
[0069] • The automated guided vehicle (AGV) is not limited to a four-wheeled vehicle; for example, it may be a six-wheeled vehicle with three sets of drive wheels arranged in the width direction, or a two-wheeled vehicle with one set of drive wheels. Furthermore, the AGV is not limited to having all wheels as drive wheels; some wheels may be driven wheels.
[0070] • Unmanned guided vehicles used in factories are not limited to AGVs; for example, autonomous mobile robots (AMRs) may also be used.
[0071] Furthermore, small mobility devices are not limited to automated guided vehicles; they may also include, for example, electric wheelchairs or mobility scooters. Small electric vehicles are, for example, vehicles with a driving speed of 10 km / h or less.
[0072] The control unit and its method described herein may be implemented by a dedicated computer provided by configuring a processor and memory programmed to perform one or more functions embodied by a computer program. Alternatively, the control unit and its method described herein may be implemented by a dedicated computer provided by configuring a processor by one or more dedicated hardware logic circuits. Alternatively, the control unit and its method described herein may be implemented by one or more dedicated computers configured by a combination of a processor and memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by the computer on a computer-readable non-transitional tangible recording medium.
[0073] The following describes the characteristic configurations extracted from each of the embodiments described above. [Configuration 1] Input axis (70b), An output shaft (72b) extending in the direction in which the input shaft extends, A speed change mechanism (70a, 71a, 72a) that changes the rotational speed of the input shaft and transmits it to the output shaft, A case (60) housing the input shaft, the output shaft, and the gear shift mechanism, A brake mechanism (80) that applies braking torque to at least one of the input shaft and the output shaft, Equipped with, The aforementioned brake mechanism is a transmission (50) housed in the aforementioned case. [Configuration 2] The aforementioned gear shifting mechanism is a reduction mechanism that reduces the rotational speed of the input shaft and transmits it to the output shaft. The transmission according to configuration 1, wherein the brake mechanism applies braking torque to the input shaft among the input shaft and the output shaft. [Configuration 3] The aforementioned brake mechanism is A rotating part (81) is provided on the input shaft and rotates integrally with the input shaft, A pressing portion (82a, 83a) that applies braking torque to the input shaft by contacting the rotating portion and stops applying braking torque to the input shaft by moving away from the rotating portion, The position-changing parts (90, 100, 110, 111, 120) are operated by applying power to either bring the pressing part into contact with the rotating part or move it away from the rotating part, It has, The aforementioned position-changing section is housed in the case, and is part of the transmission according to configuration 2. [Structure 4] The rotating part is a brake drum, The aforementioned brake mechanism is A first brake shoe (82) facing the inner circumferential surface of the brake drum and including an arc-shaped portion extending along the inner circumferential surface, The second brake shoe (83) is located on the inner circumferential surface of the brake drum, facing the inner circumferential surface opposite to the surface facing the input shaft where the first brake shoe faces, and includes an arc-shaped portion extending along the inner circumferential surface. An anchor portion (84) that supports the first end of each of the first brake shoe and the second brake shoe so as to be rotatable relative to the case in the direction in which the input shaft extends, A biasing portion (85) that applies elastic force to the first brake shoe and the second brake shoe in a direction that brings the second ends of the first brake shoe and the second brake shoe closer together, It has, The pressing portion is a lining (82a, 83a) provided on the arc-shaped portion of the first brake shoe and the second brake shoe, respectively. The gear shift device according to configuration 3, wherein the position changing portion moves the lining in one of two states: either by pushing the first brake shoe and the second brake shoe apart in a direction that separates the second end of the first brake shoe and the second end of the second brake shoe, so that they are in contact with the inner circumferential surface of the brake drum, or by bringing the second end of the first brake shoe and the second end of the second brake shoe closer together, so that they are separated from the inner circumferential surface of the brake drum. [Composition 5] The aforementioned position changing unit is A cam portion (90) having a major axis direction and a minor axis direction, A support portion (121) that rotatably supports the cam portion around the direction in which the input shaft extends, Lever part (120) and An actuator (100) including a main body (101) and a movable part (101) that can move linearly relative to the main body, It has, The cam portion and the movable portion are connected by the lever portion. In a first state in which the first end of the cam portion in the longitudinal direction abuts against the second end of the first brake shoe and the second end of the cam portion in the longitudinal direction abuts against the second end of the second brake shoe, the first brake shoe and the second brake shoe are spread apart so that the lining abuts against the inner circumferential surface of the brake drum. In a second state in which the first end of the cam portion in the minor axis direction abuts against the second end of the first brake shoe and the second end of the cam portion in the minor axis direction abuts against the second end of the second brake shoe, the second end of the first brake shoe and the second end of the second brake shoe are brought closer together and the lining is spaced apart from the inner circumferential surface of the brake drum, The gear change device according to configuration 4, wherein the position changing section is configured such that when the tip position of the movable section is set to a first position, the operating state of the cam section is set to the first state, and when the tip position of the movable section is set to a second position closer to the main body than the first position, the operating state of the cam section is set to the second state. [Composition 6] The case has a shape in which the longitudinal direction is perpendicular to the input shaft and the output shaft, The input shaft and the output shaft are arranged side by side in the longitudinal direction of the case. The aforementioned reduction mechanism is The input side spur gear (70a) provided on the input shaft, An output spur gear (72a) is provided on the output shaft and has a larger diameter than the input spur gear, It has, Within the aforementioned case, the actuator is provided on the side opposite to the output shaft with respect to the input shaft. The movable part is operable in the longitudinal direction of the case and in a direction perpendicular to the input shaft. The transmission according to configuration 5, wherein the cam portion and the support portion are positioned further away from the input shaft than the input-side spur gear in the direction from the input shaft toward the cam portion. [Composition 7] The actuator is a solenoid coil having a coil portion as the main body and a movable iron core as the movable part. The position changing section has a spring (110) that applies elastic force to the lever section so that the position of the movable section becomes the first position. The gear shift device according to configuration 5 or 6, wherein the position changing unit is configured such that when the main body is energized, the position of the movable part is set to the second position, and when the energization to the main body is stopped, the position of the movable part is set to the first position. [Structure 8] The movable part is operable in the longitudinal direction of the case and in a direction perpendicular to the input shaft. The transmission according to configuration 7, wherein the spring extends in the operating direction of the movable part and is provided alongside the solenoid coil in the direction in which the input shaft extends. [Composition 9] A transmission described in any one of configurations 5 to 8, A motor (30) that applies rotational torque to the input shaft of the transmission, An electric drive unit (20) equipped with and mounted on a vehicle (10,10a). [Configuration 10] In an in-vehicle system comprising multiple electric drive devices as described in Configuration 9, In each of the aforementioned electric drive devices, the output shaft extends from an output-side opening formed on the first end side in the longitudinal direction of the case to the outside of the case. In each of the above-mentioned electric drive devices, the input shaft extends toward the input-side opening formed on the second end of the case in the longitudinal direction of the case, In each of the aforementioned electric drive devices, the input-side opening is formed on the side opposite to the output-side opening with respect to the axis extending in the longitudinal direction of the case. In each of the above-mentioned electric drive devices, the motor is mounted in the case at the position of the input-side opening. In each of the aforementioned electric drive devices, the output shaft is connected to the drive wheel (12) of the vehicle. A right-side unit, which is an electric drive device that rotates the right-side drive wheel of the vehicle, and a left-side unit, which is an electric drive device that rotates the left-side drive wheel of the vehicle, are provided side by side in the vehicle width direction on the vehicle body (11). An in-vehicle system in which the right-side device and the left-side device are arranged such that the longitudinal direction of the cases of the right-side device and the left-side device, which are aligned in the vehicle width direction, faces the vehicle length direction. [Composition 11] The in-vehicle system according to configuration 10, wherein the width dimension of the vehicle body is smaller than the length dimension of the vehicle body. [Composition 12] The vehicle is an automated guided vehicle used in a workplace, as described in configuration 9 or 10 of the vehicle-mounted system. [Explanation of symbols]
[0074] 10...Automated guided vehicle, 30...Motor, 50...Reduction gear, 60...Case, 70b...Input shaft, 72b...Output shaft, 80...Brake mechanism.
Claims
1. An electric drive unit (20) mounted on a vehicle (10, 10a), A transmission (50) having an input shaft (70b), an output shaft (72b) extending in the direction in which the input shaft extends and rotating the drive wheels of the vehicle, a gear shift mechanism (70a, 71a, 72a) that changes the rotational speed of the input shaft and transmits it to the output shaft, a case (60) housing the input shaft, the output shaft and the gear shift mechanism, and a brake mechanism (80) that applies braking torque to the input shaft, A motor (30) that applies rotational torque to the input shaft of the transmission, The system includes a control board (41) and The control board controls the motor in order to apply rotational torque to the input shaft, based on commands from a higher-level ECU to the control board. The brake mechanism is an electric drive device that, when energized by a command from the higher-level ECU, stops the application of the braking torque while the control board is controlling the motor, and applies the braking torque when the power is stopped.
2. The electric drive device according to claim 1, wherein the vehicle is an automated guided vehicle.
3. The aforementioned brake mechanism is A rotating part (81) is provided on the input shaft and rotates integrally with the input shaft, The pressing portions (82a, 83a) apply the braking torque by contacting the rotating portion and stop applying the braking torque by moving away from the rotating portion, Position changing units (90, 100, 110, 111, 120) that, when the power supply is cut off, bring the pressing portion into contact with the rotating portion, and when power is supplied by a command from the higher-level ECU, move the pressing portion away from the rotating portion, An electric drive device according to claim 1 or 2, having the following features.
4. The electric drive device according to claim 1 or 2, wherein the gear shifting mechanism is a reduction mechanism that reduces the rotational speed of the input shaft and transmits it to the output shaft.
Citation Information
Patent Citations
Method for removing deposit on throat of converter by heating and cutting
JP1986048509A