Electric roller

Abstract

Provided is an electric roller capable of improving the braking force of a brake system. The electric roller includes: an electric motor for a rolling wheel that drives the rolling wheel; an inverter for a rolling wheel that controls the rotation speed of the electric motor for a rolling wheel; a control unit (3) that outputs a signal to the inverter for the rolling wheel in accordance with the inclination of a forward / reverse lever (17); an electric brake (61) that outputs a zero rotation signal to the inverter for the rolling wheel and causes a vehicle to decelerate or stop when the forward / reverse lever is in neutral; and a mechanical brake (62) that mechanically holds the stopped state of the vehicle. The control unit (3) comprises a mechanical brake state determination means (400) that automatically determines the state of the mechanical brake (62) at least either when the vehicle starts moving or when the vehicle is stopped.

Description

Electric Roller

[0001] The present invention relates to a powered roller.

[0002] For example, Patent Document 1 discloses a road compaction vehicle (compaction roller) for compacting road surfaces. A conventional compaction roller includes a pair of compaction wheels, a vehicle frame, an engine, a hydraulic pump, a hydraulic motor for traveling, a hydraulic motor for vibration, and a brake mechanism for braking the compaction wheels. Conventional compaction rollers are driven by an engine to drive a hydraulic pump, which then rotates a hydraulic motor for traveling using hydraulic pressure. Furthermore, the vehicle accelerates, decelerates, or stops by adjusting the oil discharge force according to the input amount of a forward / reverse lever.

[0003] JP 2010-149784 A

[0004] Incidentally, when a conventional hydraulically driven roller is replaced with an electric roller driven by an electric motor, a mechanical brake and an electric brake can be considered as a brake system for braking the roller.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an electric roller that can improve the braking force of a brake system.

[0006] In order to achieve the above-mentioned object, the electric roller of the present invention comprises a pair of rolling wheels installed at the front and rear respectively, a body frame that rotatably supports the rolling wheels, an electric motor for the rolling wheels that drives the rolling wheels, a rolling wheel inverter that controls the rotation speed of the electric motor for the rolling wheels, a battery that supplies power to the electric motor for the rolling wheels and the rolling wheel inverter, a control unit that outputs a signal to the rolling wheel inverter depending on the tilt of a forward / reverse lever, an electric brake that outputs a 0 rotation signal to the rolling wheel inverter to slow down or stop the vehicle when the forward / reverse lever control bar is in neutral, and a mechanical brake that mechanically holds the vehicle stopped, and is characterized in that it does not have an internal combustion engine, the rolling wheels are powered only by the battery, and the control unit is equipped with a mechanical brake state determination means that automatically determines the state of the mechanical brake at least when the vehicle starts to move or when it stops moving.

[0007] According to the present invention, the vehicle includes an electric brake that outputs a zero rotation signal to the roller wheel inverter to slow down or stop the vehicle when the forward / reverse lever is in neutral, and a mechanical brake that mechanically maintains the vehicle in a stopped state. In this invention, the control unit includes mechanical brake state determination means that automatically determines the state of the mechanical brake either when the vehicle starts to move or when the vehicle is stopped. When the mechanical brake is in an on state and the vehicle starts to move from a stopped state, this mechanical brake state determination means determines whether the motor torque (driving torque) of the roller wheel electric motor is equal to or greater than a predetermined value to determine whether the mechanical brake is exerting braking force. If the determination of the mechanical brake's braking force determines that there is no braking force, the control unit turns on the electric brake and maintains the vehicle in a stopped state.

[0008] Furthermore, when the vehicle stops from a moving state, the mechanical brake state determination means activates the electric brake once to control the running electric motor to maintain 0 revolutions, and then activates the mechanical brake again, and when the 0 revolution maintenance control of the electric brake is released, determines whether the number of revolutions of the running electric motor is 0, thereby determining whether the mechanical brake is exerting braking force. If it is determined that there is no braking force in the determination of the braking force of the mechanical brake, the control unit (mechanical brake state determination means) turns the electric brake on again to maintain the vehicle at a stop.

[0009] In this way, in the present invention, even if a serious error occurs that causes the braking force of the mechanical brake to become ineffective, the vehicle can be maintained in a stopped state by controlling the electric brake, thereby improving the braking force of the brake system.

[0010] In the present invention, when it is determined that there is no braking force in the determination of the braking force of the mechanical brake, it is preferable to at least one of issueing an alarm and displaying a message on a display means of the vehicle.

[0011] Furthermore, in the present invention, when it is determined that there is no braking force in the braking force determination of the mechanical brake, it is preferable that the vehicle power supply be switched from the on state to the off state only when an error release operation is input.

[0012] According to the present invention, an electric roller capable of improving the braking force of a brake system can be obtained.

[0013] 17A and 17B are a side view of an electric roller according to a first embodiment of the present invention; a plan view of an electric roller according to the first embodiment; a rear view of an electric roller according to the first embodiment; a block diagram showing the configuration of the electric roller according to the first embodiment; a schematic diagram of the operation of the electric roller according to the first embodiment; a block diagram showing the power supply system and control system of the electric roller according to the first embodiment; a rear view showing the dashboard of the electric roller according to the first embodiment; a side view showing the dashboard of the electric roller according to the first embodiment; a side view showing the brake pedal of the electric roller according to the first embodiment when moving forward; a side view of the electric roller according to the first embodiment when the brake pedal is depressed; a partially see-through side view of the electric roller according to the first embodiment; a partially see-through plan view of the electric roller according to the first embodiment; a cross-sectional view showing the front wheel of the electric roller according to the first embodiment; a plan view showing the first gear box of the electric roller according to the first embodiment; a cross-sectional view taken along line XV-XV of FIG. 14; a cross-sectional view taken along line XVI-XVI of FIG. 14; a cross-sectional view showing the periphery of the rear wheel of the electric roller according to the first embodiment; a cross-sectional view taken along line XVIII-XVIII of FIG. 17; a side view showing the steering system of the electric roller according to the first embodiment; a plan view showing the steering system of the electric roller according to the first embodiment; a graph showing the relationship between time and rotation speed of a comparative example at start-up. 1 is a graph showing the relationship between time and rotation speed in a comparative example when stopped. FIG. 1 is a graph showing the relationship between time and rotation speed of the drive command values ​​of the electric motors for the rolling wheels of the comparative example and the example. FIG. 2 is a graph showing the relationship between time and rotation speed in an example when starting up. FIG. 3 is a graph showing the relationship between time and rotation speed in an example when stopped. FIG. 4 is a graph showing the relationship between time and rotation speed of the drive command values ​​of the electric motors for the rolling wheels of a modified example. FIG. 5 is a cross-sectional view showing the front wheels of an electric roller according to a fourth embodiment. FIG. 6 is a block diagram showing the configuration of an electric roller according to the fourth embodiment. FIG. 7 is a plan view showing the top surface of the dashboard of an electric roller according to the fourth embodiment. FIG. 8 is a block diagram of a multi-stage speed change control unit of an electric roller according to the fourth embodiment. FIG. 9 is a flowchart showing multi-stage speed change control by a speed change switch of an electric roller according to the fourth embodiment. FIG. 10 is a flowchart showing control of acceleration of an electric roller according to the fourth embodiment.10 is a table showing an overview of each brake in the electric roller. FIG. 11 is a block diagram showing the flow of brakes in the electric roller. FIG. 12 is a block diagram showing mechanical brake error control in the electric roller according to the fifth embodiment. FIG. 13 is a flowchart showing electric brake control modes when the vehicle starts to travel in the electric roller according to the fifth embodiment. FIG. 14 is a flowchart showing electric brake control modes when the vehicle stops traveling in the electric roller according to the fifth embodiment.

[0014] [First embodiment] The electric roller of the present invention will be described in detail with reference to the drawings. The embodiments and modifications described below are merely examples, and each embodiment and modification can be used in combination as appropriate. In the drawings, up and down, left and right, and front and back correspond to the direction of travel of the electric roller.

[0015] <Overall Schematic Configuration> As shown in Figures 1 to 4, the electric roller 1 mainly includes a front wheel R1, a rear wheel R2, a body frame 2, an electric motor M (M1 to M4), an inverter J (J1 to J4), a battery K (K1 to K3), and a control unit 3.

[0016] The front wheel R1 is rotatably supported by a pair of front wheel side plates SP1, SP2 provided at the front of the body frame 2. The front wheel R1 is a rolling wheel that rolls on the road surface, and in this embodiment is configured as a single iron wheel. The front wheel R1 may be configured as a plurality of tires or a plurality of iron wheels.

[0017] The rear wheels R2 are rotatably supported at the rear of the body frame 2. The rear wheels R2 are rolling wheels that roll on the road surface, and in this embodiment are composed of four tires (R2A, R2B, R2C, R2D). The rear wheels R2 may also be composed of a single or multiple steel wheels.

[0018] The vehicle frame 2 is a vehicle body that rotatably supports the front wheels R1 and the rear wheels R2. The vehicle frame 2 includes a front frame 11, a rear frame 12, a driver's seat 13, and a dashboard 14. Front wheel side plates SP1, SP2 are fixed to the front of the front frame 11. A front space 15 that houses an inverter J and a battery K is formed inside the front frame 11. The rear frame 12 includes the driver's seat 13 and the dashboard 14, and a rear space 16 that houses an electric motor M, an inverter J, a gearbox, etc. The rear space 16 includes a first rear space 16a formed below the feet of the driver's seat 13 and a second rear space 16b formed below the driver's seat 13. The front frame 11 and the rear frame 12 are connected via joint pins that are parallel to the vertical direction. The electric roller 1 of this embodiment is an articulated type, but may also be a rigid type.

[0019] As shown in Figure 4, the front wheel electric motor M1 is an electric motor that drives the front wheel R1. The front wheel electric motor M1 is driven in accordance with a drive command value input from the control unit 3 to the front wheel inverter J1. The right rear wheel electric motor M2 is an electric motor that drives the rear wheel R2. The right rear wheel electric motor M2 is driven in accordance with a drive command value input from the control unit 3 to the right rear wheel inverter J2.

[0020] The left rear wheel electric motor M3 is an electric motor that drives the rear wheel R2. The left rear wheel electric motor M3 is driven in accordance with a drive command value input from the control unit 3 to the left rear wheel inverter J3. The front wheel electric motor M1, the right rear wheel electric motor M2, and the left rear wheel electric motor M3 are collectively referred to as the "compaction wheel electric motors." Furthermore, the front wheel inverter J1, the right rear wheel inverter J2, and the left rear wheel inverter J3 are collectively referred to as the "compaction wheel inverters."

[0021] 4, the vibration electric motor M4 is an electric motor that drives the vibration generating shaft 130. The vibration electric motor M4 is driven in accordance with a drive command value input from the control unit 3 to the vibration inverter J4.

[0022] As shown in FIG. 6 , the battery K supplies power to various components such as the electric motor M and the inverter J. In this embodiment, the battery K includes a 48V battery K1, a 24V battery K2, and a 12V battery K3, and is housed in a battery case KA (see FIG. 11 ) located in the front space 15. The 48V battery K1 and the 24V battery K2 are lithium-ion secondary batteries. The 12V battery K3 is a lead-acid battery. In this embodiment, three types of batteries with different voltages are provided, but any number of types may be provided, or the battery K may be configured with a single voltage. The battery management unit 71 uses, for example, a BMU (Battery Management Unit). The control unit 3 is a controller that controls the various components. The control unit 3 uses, for example, a VCU (Vehicle Control Unit). The battery K, the battery management unit 71, and the control unit 3 are linked via CAN communication for transmitting battery information.

[0023] As shown in FIG. 5 , in the electric roller 1, the control unit 3 outputs drive command values ​​to the inverters J (J1 to J3) in accordance with the tilt angle of the forward / reverse lever 17 operated by the operator OP. The electric motors M (M1 to M3) rotate in accordance with the drive command values ​​input to each inverter J, causing the vehicle to travel forward or backward. While conventional vehicles burn fuel such as gasoline to operate an internal combustion engine (engine, etc.) to drive a hydraulic pump and drive rolling wheels, the electric roller 1 of this embodiment differs in that it does not have an internal combustion engine and uses a battery K as the only power source for the rolling wheels. Furthermore, while conventional vehicles adjust the acceleration and deceleration of the vehicle's traveling speed using hydraulic control, the electric roller 1 of this embodiment differs in that it controls the acceleration and deceleration using a drive command value output from the control unit 3 to the inverter J.

[0024] <Traveling System> Next, the travelling system will be described in detail. As shown in Figures 1 and 2, the driver's seat 13 is where the operator OP sits, and faces the dashboard 14. The dashboard 14 is a box-shaped body installed in front of the driver's seat 13, and is provided with a brake pedal BP that protrudes rearward, and a display 18 is disposed on the upper surface. The steering wheel 19 is a device that determines the direction of travel of the vehicle, and is provided on the upper surface of the dashboard 14. The steering wheel 19 is connected to Orbitroll (registered trademark, the same applies hereinafter; see Figures 4 and 19) 51 installed inside the dashboard 14.

[0025] As shown in Fig. 1, the brake pedal BP is provided at the bottom rear of the dashboard 14 and is configured to apply the brakes when the operator OP steps on it. The forward / reverse levers 17, 17 are provided on both sides of the dashboard 14 and are levers that can be tilted to a neutral position, a forward position, and a reverse position. The forward / reverse lever 17 may be configured to be provided on only one side of the dashboard 14.

[0026] As shown in Fig. 7, the forward / reverse levers 17, 17 are connected to both ends of a shaft 21. The shaft 21 is disposed inside the dashboard 14 along the width direction of the vehicle. As shown in Fig. 8, the shaft 21 is provided with a plate-shaped base plate 22 that rotates in synchronization with the shaft 21 and is fixed perpendicular to the shaft 21.

[0027] As shown in Fig. 9, the brake pedal BP is configured to move in conjunction with a shaft 21. A first pin 22a and a second pin 22b that protrude in the width direction of the vehicle are formed on the base plate 22. The first pin 22a and the second pin 22b are disposed at approximately the same distance from the shaft 21. The brake pedal BP includes a main body plate 23, a pedal portion 24, a rotation fulcrum portion 25, and a connecting fulcrum portion 26.

[0028] The main body plate 23 is a plate-like member having a pedal portion 24 at the rear. The front end of the main body plate 23 is rotatably fixed via a bracket 27 fixed to the front wall of the dashboard 14. The rotation fulcrum portion 25 serves as the rotation center of the brake pedal BP. The connecting fulcrum portion 26 is formed on the upper part of the main body plate 23.

[0029] The connecting fulcrum 26 is connected to the base plate 22 via a first brake pedal rod 28 and a second brake pedal rod 29. The first brake pedal rod 28 and the second brake pedal rod 29 are rod-shaped members. The lower ends of the first brake pedal rod 28 and the second brake pedal rod 29 are connected to the connecting fulcrum 26 by pin connections.

[0030] An elongated hole 28a into which the first pin 22a fits loosely is formed at the upper end of the first brake pedal rod 28. An elongated hole 29a into which the second pin 22b fits loosely is formed at the upper end of the second brake pedal rod 29. When viewed from the side, the first brake pedal rod 28 and the second brake pedal rod 29 are V-shaped.

[0031] In the initial position (when the forward / reverse lever 17 is in the neutral position), the base plate 22 is generally horizontal. The first pin 22a and the second pin 22b are located slightly above the center in the height direction of the elongated holes 28a and 29a.

[0032] 9 is a diagram illustrating the operation of the base plate 22 and its surroundings when the forward / reverse lever 17 is tilted to its fullest position in the forward direction. As shown in FIG. 9, when the forward / reverse lever 17 is tilted forward, the shaft 21 and the base plate 22 rotate counterclockwise around the shaft 21. At this time, the first pin 22a is positioned at the upper end of the elongated hole 28a of the first brake pedal rod 28. Meanwhile, the second pin 22b is positioned slightly below the center in the height direction of the elongated hole 29a of the second brake pedal rod 29. Even when the forward / reverse lever 17 is tilted forward, the first pin 22a and the second pin 22b each move within the elongated holes 28a and 29a, so the position of the brake pedal BP does not change.

[0033] Although not specifically shown in the drawings, when the forward / reverse lever 17 is tilted rearward to move the vehicle backward, the base plate 22 rotates clockwise in synchronization with the shaft 21. In this case, as in the case of moving forward, even if the forward / reverse lever 17 is tilted rearward, the first pin 22a and the second pin 22b move within the elongated holes 28a, 29a, respectively, and therefore the position of the brake pedal BP does not change.

[0034] Figure 10 is an operational diagram of the base plate 22 and its surroundings when the brake pedal BP is depressed. As shown in Figure 10, when the operator OP depresses the brake pedal BP, the brake pedal BP rotates downward around the rotation fulcrum 25. Accordingly, the first brake pedal rod 28 and the second brake pedal rod 29 are pulled downward, so that the first pin 22a and the second pin 22b are positioned at the upper ends of the elongated holes 28a and 29a, respectively, and the base plate 22 rotates by a predetermined angle and becomes substantially horizontal. Synchronously with this, the shaft 21 and the forward / reverse lever 17 also rotate and are positioned in the neutral position, so that the brake is activated and braking occurs.

[0035] As described above, the operator OP can return the forward / reverse lever 17 to the neutral position or depress the brake pedal BP, thereby returning the forward / reverse lever 17 to the neutral position and braking the vehicle. Details of the brake system will be described later.

[0036] As shown in FIGS. 4 and 7 , a potentiometer 31 is installed inside the dashboard 14. The potentiometer 31 is a device that detects the tilt angle of the forward / reverse lever 17. A connecting plate 34 that protrudes in a direction perpendicular to the axial direction is provided on the shaft 21. Meanwhile, the potentiometer 31 is provided with a connecting plate 35 that is connected to the potentiometer 31 and rotates in synchronization with the connecting plate 34. A connecting rod 33 that connects the connecting plates 34, 35 to each other is also provided. When the forward / reverse lever 17 is tilted, the tilt angle can be detected by the potentiometer 31 through a link mechanism formed by the connecting plates 34, 35 and the connecting rod 33. The detection result of the potentiometer 31 is output to the control unit 3.

[0037] 7 , a limit switch (neutral sensor) 32 is installed inside the dashboard 14 near the shaft 21. The limit switch 32 is a device that detects the neutral position of the forward / reverse lever 17. The detection result of the limit switch 32 is output to the control unit 3.

[0038] Furthermore, a display 18 provided on the top surface of the dashboard 14 displays various vehicle information held by the control unit 3, such as a speedometer, remaining charge of the battery K, mileage, an hour meter, alert information, etc. The display 18 may be configured to display a touch-type operation panel. The display 18 may also be configured to display information related to compaction, such as the compaction status of the construction site, map information of the compacted area, and location information.

[0039] As shown in FIGS. 4 and 6, the dashboard 14 is provided on its upper surface with a travel H / L switch 36, a parking switch 37, a vibration switch 39, a lighting switch, an alarm switch, and the like.

[0040] The travel H / L switch 36 is a switch that allows the user to select a high-speed travel mode or a low-speed travel mode. When the forward / reverse lever 17 is fully tilted (full throttle), for example, the high-speed travel mode is set to 10 km / h, and the low-speed travel mode is set to 5 km / h. These speeds can be set as appropriate.

[0041] The parking switch 37 is a switch that can select whether to activate or release the parking brake. The vibration switch 39 is a switch that can select whether to turn on or off vibration of the front wheel R1. A switch that can control the intensity (number of rotations) of the vibration in conjunction with the vibration switch 39 may be provided. The lighting switch is, for example, a switch that can select whether to turn on or off hazard lights that flash when stopping the vehicle. The alarm switch is, for example, a switch that can select whether to turn on or off a backup buzzer when backing up. The ON or OFF status of these function switches (buttons) may be displayed on the display 18.

[0042] 4, the inverter J includes a front wheel inverter J1, a right rear wheel inverter J2, a left rear wheel inverter J3, and a vibration inverter J4. The inverter J controls the frequency based on a drive command value output from the control unit 3, and changes the rotation speed of each electric motor M.

[0043] 4, the electric motors M include a front wheel electric motor M1, a right rear wheel electric motor M2, a left rear wheel electric motor M3, and a vibration electric motor M4. The type of electric motor M may be selected as appropriate, but in this embodiment, induction motors are used for all of them.

[0044] <Structure of Front Wheel R1 (Vibration System)> As shown in Figure 13, the front wheel R1 is equipped with a roll 111, with a front wheel electric motor M1 and a vibration electric motor M4 installed at both ends of the vehicle width direction. The roll 111 has a hollow cylindrical shape, and a first head plate 112 and a second head plate 113 are provided on its inner surface with a gap between them. A hollow cylindrical vibration exciter case 114 is fixed between the first head plate 112 and the second head plate 113. The interior of the vibration exciter case 114 is filled with lubricating oil. A first holder 115 is attached to the first head plate 112, and a second holder 116 is attached to the second head plate 113. The first holder 115 is supported by a cylindrical housing 118 via bearings 117. The housing 118 hangs down from the left side surface of the body frame 2, and its lower end is attached to the front wheel side plate SP1 located inside the roll 111 via vibration-isolating rubber 121 and a support member 122.

[0045] The second holder 116 is fixed to the second end plate 113. The front wheel electric motor M1 is attached via a motor mounting plate 124 to the front wheel side plate SP2, which hangs down from the right side of the body frame 2 and has its lower end positioned at the roll 111. A reduction gear mechanism 125 is installed in the output portion M1a of the front wheel electric motor M1. The output portion M1a is connected to the second end plate 113 via vibration isolating rubber 123 and a support member 126. A cover 127 is attached to the second holder 116, covering the right end portion.

[0046] As a result of the above, when the front wheel electric motor M1 rotates, its rotational force is reduced in speed by the reduction gear mechanism 125 and transmitted to the support member 126 and the second mirror plate 113, and the roll 111 runs and rotates while the first holder 115 is supported by the housing 118.

[0047] On the other hand, the vibration electric motor M4 is attached via a motor attachment plate 128 connected to the front wheel side plate SP1. A joint member (e.g., a constant velocity joint) 129 connects the output shaft of the vibration electric motor M4 and a vibration generating shaft 130.

[0048] The vibration generating shaft 130 is disposed within the vibration generator case 114 and extends in the vehicle width direction around an axis that is coaxial with the roll 111. The vibration generating shaft 130 includes a main body 131, support shafts 132 and 133 provided at both ends of the main body 131, and an eccentric weight 134. The main body 131 is a shaft-shaped portion, and is provided at both ends with support shafts 132 and 133 that are smaller in diameter than the main body 131. The support shaft 132 is supported by the first holder 115 via a bearing 135. The support shaft 133 is supported by the second holder 116 via a bearing 136. The eccentric weight 134 is provided on the outer circumferential surface of the main body 131.

[0049] As described above, when the vibrating electric motor M4 rotates, the rotational force is transmitted to the vibration generating shaft 130 via the joint member 129, and the vibration generating shaft 130 rotates relative to the first holder 115 and the second holder 116. At that time, the vibration generating shaft 130 is provided with the eccentric weight 134, so the roll 111 vibrates.

[0050] When the operator OP operates the vibration switch 39 (see FIG. 4), a vibration signal is output from the control unit 3 to the vibration inverter J4, and the vibration electric motor M4 is activated based on the drive instruction value of the vibration inverter J4. A new operation switch may be provided to set, for example, a high vibration mode or a low vibration mode. Rotating the vibration electric motor M4 at high speed increases the vibration, while rotating it at low speed decreases the vibration. Furthermore, the rotation speed of the vibration electric motor M4 may be freely controlled in response to the operation of the operator OP, allowing the strength of the vibration to be adjusted.

[0051] In this embodiment, the vibration generating shaft 130 (vibration system) is provided only on the front wheel R1, but it may also be provided on the rear wheel R2, or only on the rear wheel R2.

[0052] 14 to 18, the rotational forces of the right rear wheel electric motor M2 and the left rear wheel electric motor M3 are transmitted to the rear wheel R2 via a reduction mechanism. The reduction mechanism is made up of a first gear box 200A and a second gear box 200B, and is provided from the second rear space 16b of the rear space 16 to the rear wheel R2. As shown in FIG. 14, the right rear wheel electric motor M2 and the left rear wheel electric motor M3 are arranged so that their output shafts face each other and are parallel to the vehicle width direction.

[0053] The first gearbox 200A includes a first gear 201, a second gear 204, a third gear 205, and a fourth gear 207. The first gearbox 200A is a rectangular parallelepiped box-shaped body and is disposed inside the second rear space 16b. The first gear 201, the second gear 204, the third gear 205, and the fourth gear 207 all have rotation axes that are parallel to the vehicle width direction. The inside of the first gearbox 200A is filled with lubricating oil.

[0054] The first gear 201 includes a shaft portion 201 a and a gear portion 201 b provided on the shaft portion 201 a. Both ends of the shaft portion 201 a are connected to the output shafts of the electric motor M2 for the right rear wheel and the electric motor M3 for the left rear wheel, respectively, and are supported by bearings 202, 202 provided in the first gear box 200A.

[0055] The second gear 204 includes a shaft portion 204a, and a large-diameter gear 204b and a small-diameter gear 204c provided on the shaft portion 204a. Both ends of the shaft portion 204a are supported by bearings 203, 203 provided in the first gear box 200A. The large-diameter gear 204b is meshed with the gear portion 201b of the first gear 201 and the gear portion 205b of the third gear 205, respectively. The small-diameter gear 204c is meshed with the large-diameter gear 207b of the fourth gear 207.

[0056] The third gear 205 includes a shaft portion 205a and a gear portion 205b provided on the shaft portion 205a. The shaft portion 205a is supported by a bearing 206 provided in the first gear box 200A. A non-excited brake (negative brake) 62 is connected to the tip of the shaft portion 205a. In other words, the non-excited brake 62 is connected to the outside of the first gear box 200A via the shaft portion 205a.

[0057] The fourth gear 207 includes a shaft portion 207a, and a large-diameter gear 207b and a small-diameter gear 207c provided on the shaft portion 207a. The shaft portion 207a communicates between the first gear box 200A and the second gear box 200B, and is supported by bearings 209, 209 provided in the second gear box 200B. A seal member 208 is interposed between the first gear box 200A and the outer periphery of the shaft portion 207a. The large-diameter gear 207b is disposed in the first gear box 200A and meshes with the small-diameter gear 204c of the second gear 204. The small-diameter gear 207c is disposed in the second gear box 200B.

[0058] As shown in Figure 17, the second gear box 200B is arranged next to the first gear box 200A and is a vertically long box-shaped body arranged from the second rear space 16b to the rear wheel R2. The fifth gear 210 includes a shaft portion 210a and a gear portion 210b provided on the shaft portion 210a. The shaft portion 210a is supported by a bearing 211 provided in the second gear box 200B. The gear portion 210b is meshed with the small-diameter gear 207c of the fourth gear 207 and the gear portion 213b of the sixth gear 213, respectively.

[0059] The sixth gear 213 includes a shaft 213a and a gear portion 213b provided on the shaft 213a. The shaft 213a is a shaft extending across the tires R2A to R2D of the rear wheel R2. Holders 218A and 218B extend from the lower part of the second gearbox 200B to the left and right in the vehicle width direction and support the shaft 213a via bearings 214. The left end of the shaft 213a is fastened to a hub 216A via a fastening portion 217A. The hub 216A also supports disc wheels DWA and DWB that are placed inside the tires R2A and R2B.

[0060] Similarly, the right end of the shaft portion 213a is fastened to a hub 216B via a fastening portion 217B. The hub 216B supports the disc wheels DWC and DWD disposed inside the tires R2C and R2D.

[0061] In the reduction mechanism configured as described above, the rotational forces of the right rear wheel electric motor M2 and the left rear wheel electric motor M3 are transmitted to the shaft 213a via the first gear 201, the second gear 204, the fourth gear 207, the fifth gear 210 and the sixth gear 213, and are also transmitted to the rear wheel R2 via the hubs 216A and 216B.

[0062] <Steering System> Next, the steering system will be described. As shown in Figure 19, the steering system includes an orbit roll 51, an electric hydraulic pump 52, a filter 53, an accumulator 54, hydraulic cylinders 55, 55, and a pressure switch 56 (see Figure 4). These components of the steering system are connected by piping to form a hydraulic circuit.

[0063] The orbit roll 51 is connected to the steering 19 and is located inside the dashboard 14. The electric hydraulic pump 52 is electrically connected to the 24V battery K2 and is located in the first rear space 16a. The filter 53 is connected to a portion of the piping and is a component that removes impurities such as dust and iron contained in the hydraulic oil. The accumulator 54 is connected to a portion of the piping and is a device that stores and releases the fluid energy of the hydraulic oil. The filter 53 and the accumulator 54 are located in the second rear space 16b. As shown in FIG. 20 , the hydraulic cylinders 55, 55 are cylinders that connect the front frame 11 and the rear frame 12 and are located on both sides in the vehicle width direction. The extension and contraction of the hydraulic cylinders 55, 55 enables the vehicle to turn left and right.

[0064] 4, the pressure switch 56 checks the pressure in the hydraulic circuit and determines whether to start or stop the electric hydraulic pump 52. When the control unit 3 receives a detection signal from the pressure switch 56 and the pressure in the hydraulic circuit drops below a predetermined value, it starts the electric hydraulic pump 52, and when the pressure is above the predetermined value, it stops the electric hydraulic pump 52. The pressure switch 56 can also detect pressure errors in the hydraulic circuit.

[0065] The steering system includes an electric hydraulic pump 52, hydraulic cylinders 55, 55 driven by the pressure oil discharged from the electric hydraulic pump 52, and a steering valve (not shown) that controls the direction and flow rate of the pressure oil supplied from the electric hydraulic pump 52 to the hydraulic cylinders 55, 55. The steering valve is switched according to the direction and amount of rotation of the steering wheel 19 to drive and control the hydraulic cylinders 55, 55. The switching of the steering valve according to the direction and amount of rotation of the steering wheel 19 is performed by the orbit roll 51.

[0066] <Brake System> In this embodiment, the following brake systems (1) to (3) are provided. Note that the types of brakes are not limited to those listed below and may be increased or decreased as appropriate. (1) Neutral Brake As shown in FIG. 4, the neutral brake is a brake that is activated when the forward / reverse lever 17 is placed in the neutral position by the operator OP. During a stopping operation, the vehicle is decelerated by applying regenerative motion and reverse braking of the electric motor for the rolling wheels, and is electrically stopped by the zero rotation speed holding brake (excitation brake 61). The excitation brake 61 functions as an "electric brake" (described below) that is activated when energized, and is released when de-energized.

[0067] When the forward / reverse lever 17 is in the neutral position, the limit switch 32 outputs a detection signal to the control unit 3. The control unit 3 outputs drive command values ​​to the front wheel inverter J1, the right rear wheel inverter J2, and the left rear wheel inverter J3 so that the front wheel electric motor M1, the right rear wheel electric motor M2, and the left rear wheel electric motor M3 each rotate at 0 revolutions. The control unit 3 also outputs a brake signal to the electromagnetic brake 61. After a predetermined time has elapsed since the control unit 3 output the drive command values ​​(maintaining 0 revolutions) to each inverter J, the control unit 3 activates the non-excitation brake 62 (FIGS. 4 and 14) via an activation relay while releasing the braking of the electromagnetic brake 61. This predetermined time can be set as appropriate. The non-excitation brake 62 is controlled by an activation relay connected to the control unit 3.

[0068] (2) Foot Brake (Emergency Stop) As shown in Figures 4 and 8, the foot brake is a brake that is activated by depressing the brake pedal BP. When the operator OP depresses the brake pedal BP, a foot brake signal is output to the control unit 3. The control unit 3 then cuts off power to each electric motor M. Furthermore, when the brake pedal BP is depressed, the base plate 22, which has been tilted by the mechanism shown in Figures 9 and 10 as described above, returns to a horizontal position. In other words, the shaft 21 (forward / reverse lever 17) is positioned in the neutral position, and the neutral brake described above is activated.

[0069] (3) Parking Brake The parking brake is a brake that is activated by pressing the parking switch 37, as shown in Fig. 4. When the operator OP presses the parking switch 37, a parking brake signal is output to the control unit 3. The control unit 3 activates the non-excitation brake 62. This non-excitation brake 62 functions as a "mechanical brake" that will be described later.

[0070] As shown in FIG. 16 , the non-excitation brake 62 is a mechanical disc brake that operates when de-energized. The non-excitation brake 62 is electrically connected to the 24V battery K2. When energized, the non-excitation brake 62 allows the rotor 64, which rotates in synchronization with the shaft 205a of the third gear 205, to rotate. This causes the third gear 205 to also rotate, enabling travel. On the other hand, when de-energized, the rotor 64 is clamped, preventing the rotation of the shaft 205a, and the brake operates. The non-excitation brake 62 is provided with a release lever 63. An operator OP or a worker can release the non-excitation brake 62 by operating the release lever 63.

[0071] <Electrical System> As shown in Figure 6, the battery K in this embodiment includes a 48V battery K1, a 24V battery K2, and a 12V battery K3. The 48V battery K1 and the 24V battery K2 are lithium-ion batteries. A battery management unit (BMU) 71 is a device that measures the voltage, current, temperature, etc. of each battery cell and monitors and controls the battery (lithium-ion secondary battery) K. The battery management unit 71 also has a function to display measured data, a balancing function to maintain constant voltages between each cell, and a function to detect overcharge and overdischarge. The battery management unit 71 and the control unit 3 are capable of communicating battery information via CAN communication.

[0072] The 12V battery K3 is a lead-acid battery. The 12V battery K3 is electrically connected to a starter switch 38 that starts the electric roller 1. The 12V battery K3 is also electrically connected to electrical components including lighting devices (e.g., hazard lights) 40 and alarm devices (e.g., a backup buzzer and an alert buzzer) 41. For example, even if the control unit 3 goes down, the 12V battery K3 can start (restart) the electric roller 1 and supply electricity to various electrical components.

[0073] The 48V battery K1 is electrically connected to each inverter J and each electric motor M. A DC-DC converter 42 is interposed between the 48V battery K1 and the 12V battery K3. The DC-DC converter 42 is a device that reduces the voltage in order to supply power from the 48V battery K1 to the 12V battery K3. The 24V battery K2 is electrically connected to the electric hydraulic pump 52 and the non-excitation brake 62.

[0074] The control unit (VCU) 3 is a device that determines the state of the vehicle as it changes while traveling and controls each component to maintain the optimum state. The control unit 3 controls each component that influences each other, such as the electric motor M, inverter J, and battery K, while taking into account the influence on other components.

[0075] The control unit 3 includes a calculation unit (CPU: Central Processing Unit), a memory unit, a communication unit, etc. The control unit 3 may be located anywhere, but in this embodiment, it is attached to the front of the battery case KA (see FIG. 11 ) of the battery K. The calculation unit is a component that reads out programs stored in the memory unit and causes the programs to function as functional units. The memory unit includes a RAM (Random Access Memory), a ROM (Read Only Memory), an HDD (Hard Disk Drive), etc. The memory unit stores various programs and drive instruction values ​​for each inverter J corresponding to the tilt angle of the potentiometer 31 as a drive instruction value file. The communication unit is, for example, a CAN communication unit, and is capable of communicating with each component.

[0076] The control unit 3 may also be linked to a Global Navigation Satellite System (GNSS) to acquire and utilize driving records, location information, driving conditions, and the like. The control unit 3 may also be linked to a compaction management device equipped with a sensor that acquires road surface compaction information to acquire and utilize compaction information in real time. The control unit 3 may also be linked to an autonomous driving device to enable autonomous driving by remote control. The control unit 3 may also transmit vehicle operation information (driving time, abnormality information, battery status, etc.) to a technical center, leasing company, etc., and store and manage the information.

[0077] <Operations and Effects> When the operator OP tilts the forward / reverse lever 17 forward, the vehicle moves forward, and when tilted backward, the vehicle moves backward. When the forward / reverse lever 17 is tilted, the potentiometer 31 outputs the tilt angle to the control unit 3. The control unit 3 outputs drive command values ​​to the front wheel inverter J1, the right rear wheel inverter J2, and the left rear wheel inverter J3, and operates the electric motors for the rolling wheels based on the drive command values. Increasing the tilt angle of the forward / reverse lever 17 makes the vehicle travel faster, and decreasing it makes the vehicle travel slower. When the forward / reverse lever 17 is returned to the neutral position, the neutral brake is activated and the electric roller 1 stops.

[0078] When the operator OP operates the vibration switch 39, a vibration signal is output to the control unit 3. The control unit 3 sends a vibration instruction value to the vibration inverter J4, and operates the vibration electric motor M4 based on the vibration instruction value. This causes the vibration generating shaft 130 to rotate, and the front wheel R1 to vibrate.

[0079] According to the electric roller 1 according to the present embodiment described above, fuel consumption and greenhouse gas emissions can be substantially eliminated by electrification. Furthermore, because electric motorization can reduce noise and substantially eliminate greenhouse gas emissions, the burden on the operator OP can be reduced and the working environment can be improved. Furthermore, because no hydraulic pump or hydraulic circuit is used for traveling as in the past, there is no need to replace hydraulic oil, resulting in excellent maintainability.

[0080] Furthermore, according to this embodiment, a plurality of electric motors for the rolling wheels (front wheel electric motor M1, right rear wheel electric motor M2, and left rear wheel electric motor M3) are provided. Although a single electric motor for the rolling wheels may be used, providing a plurality of electric motors can increase the main torque while preventing the electric motor for the rolling wheels from becoming too large. This allows the vehicle to stop and start on an uphill slope.

[0081] Furthermore, according to this embodiment, the potentiometer 31 is provided, which enables precise speed control according to the tilt of the forward / reverse lever 17. Furthermore, the limit switch 32 is provided, which makes it possible to reliably detect the neutral position. Although the neutral position can be detected using only the potentiometer 31, if an error occurs in the input from the potentiometer 31, there is a risk that the vehicle will start moving even when the forward / reverse lever 17 is in the neutral position. However, according to this embodiment, the limit switch 32 is provided, which makes it possible to reliably detect the neutral position.

[0082] Furthermore, according to this embodiment, the vehicle is equipped with electrical equipment including the lighting device 40 and the alarm 41, and is equipped with a plurality of batteries K with different voltages that are electrically connected to the electric motor for the rolling wheels and the electrical equipment, respectively. This allows power to be supplied according to the voltage of each component. Furthermore, the 48V battery K1 and the 24V battery K2 are lithium-ion batteries (storage batteries), and therefore can be charged and used repeatedly.

[0083] Furthermore, according to this embodiment, the battery K is installed in the front space 15 of the body frame 2, which allows for effective use of space and allows for downsizing. In other words, the battery K can be placed in the area where the engine was previously installed. Furthermore, the battery K can be protected by being housed in the battery case KA. The battery K may be installed only in the rear space 16, or in both the front space 15 and the rear space 16.

[0084] Furthermore, according to this embodiment, the electrical components including the lighting device 40 and the alarm device 41 are electrically connected to a 12V battery K3 made of a lead storage battery. This allows the electrical components including the lighting device 40 to function even if the control unit 3 goes down. Therefore, even if the system goes down, it is possible to issue an alert to those around, and the vehicle can be smoothly restarted or reactivated.

[0085] Furthermore, according to this embodiment, the speedometer can be displayed on the display 18 provided on the dashboard 14, and vehicle information held by the control unit 3 can also be displayed on the display 18. This allows the operator OP to grasp not only the speed, but also vehicle information held by the control unit 3, such as whether the vehicle is moving forward or backward, whether there is vibration, the amount of charge, the time, and the total distance traveled.

[0086] Furthermore, while a mechanism for vibrating the rollers may be provided as needed, according to this embodiment, the vibration generating shaft 130 is operated by a vibration inverter J4 and a vibration electric motor M4. This allows for easy vibration control of the vibration generating shaft 130, and by electrifying the vibration generating shaft 130, fuel consumption and greenhouse gas emissions are substantially eliminated. Furthermore, by electrifying the vibration generating shaft 130, noise can be reduced and greenhouse gas emissions can be substantially eliminated, thereby reducing the burden on the operator OP and improving the working environment. Furthermore, because a hydraulic pump or hydraulic circuit for vibration is not used as in conventional systems, there is no need to replace hydraulic oil, resulting in excellent maintainability.

[0087] Furthermore, according to this embodiment, by installing the vibration electric motor M4 on the sprung part (above the vibration-isolating rubber 121 (towards the vehicle body frame 2)), it is possible to reduce vibration acting on the vibration electric motor M4. Furthermore, by providing a constant velocity joint that connects the vibration generating shaft 130 and the output shaft of the vibration electric motor M4, it is possible to transmit the drive of the vibration electric motor M4 to the vibration generating shaft 130 even when an operating angle is provided.

[0088] Furthermore, according to this embodiment, since the steering system uses the electric hydraulic pump 52, electrification can substantially eliminate fuel consumption and greenhouse gas emissions. Furthermore, electrification can reduce noise and substantially eliminate greenhouse gas emissions, thereby reducing the burden on the operator OP and improving the working environment. Furthermore, according to this embodiment, since the hydraulic cylinder 55 is driven by the electric hydraulic pump 52, modifications to the steering-related mechanisms can be minimized when electrification is implemented.

[0089] Furthermore, according to this embodiment, pressure can be accumulated in the accumulator 54, which prevents the electric hydraulic pump 52 from seizing due to continuous operation and reduces energy consumption.

[0090] Furthermore, according to this embodiment, the electric hydraulic pump 52, piping, and accumulator 54 are installed in the rear space 16 of the body frame 2, which allows for effective use of the rear space 16 and reduces the number of piping and the like spanning between the front space 15 and the rear space 16.

[0091] Furthermore, according to this embodiment, the hydraulic cylinders 55 are installed on both the left and right sides of the body frame 2, which reduces or eliminates the difference in the amount of oil discharged left and right during turning, thereby stabilizing behavior during turning. Note that the number of hydraulic cylinders 55 may be just one per body frame 2. This simplifies the structure and reduces the number of parts.

[0092] Furthermore, according to this embodiment, when the forward / reverse lever 17 is in the neutral position, the control unit 3 outputs a zero rotation signal to the roller wheel inverters (front wheel inverter J1, right rear wheel inverter J2, and left rear wheel inverter J3) and activates the electromagnetic brake 61. This allows for an easy configuration of the brake system, and electrification of the brake system substantially eliminates fuel consumption and greenhouse gas emissions. Furthermore, electrification reduces noise and substantially eliminates greenhouse gas emissions, thereby reducing the burden on the operator OP and improving the working environment. Furthermore, because the brake system does not use a hydraulic circuit as in conventional systems, there is no need to replace hydraulic oil, resulting in excellent maintainability.

[0093] Furthermore, according to this embodiment, the control unit 3 activates the non-excited brake 62, which mechanically brakes the vehicle, after a predetermined time has elapsed since the activation of the electromagnetic brake 61. Activating the electromagnetic brake 61 results in continued consumption of power while the vehicle is stopped, but according to this embodiment, after the predetermined time has elapsed, the control unit 3 switches to the non-excited brake 62 and releases the electromagnetic brake 61, thereby reducing power consumption.

[0094] Furthermore, when the operator OP depresses the brake pedal BP or operates a switch (parking switch 37) provided on the dashboard 14 or the driver's seat 13, the control unit 3 activates a non-excited brake 62, which mechanically brakes the vehicle, via an activation relay. This allows the vehicle to stop in an emergency.

[0095] Furthermore, by providing a release lever 63 for releasing the non-excitation brake 62 around the driver's seat 13, the operation of releasing the non-excitation brake 62 can be easily performed.

[0096] [Second embodiment - over-rotation prevention mechanism for electric motors for rolling wheels] Next, a second embodiment of the present invention will be described. The electric roller 1 according to the second embodiment differs from the first embodiment in that it is equipped with an over-rotation prevention mechanism that prevents over-rotation of the front wheel electric motor M1, the right rear wheel electric motor M2, and the left rear wheel electric motor M3 (electric motors for rolling wheels). The second embodiment will be described mainly focusing on the differences from the first embodiment. Note that the drive command values ​​and times shown below are merely examples, and these numerical values ​​can be set as appropriate.

[0097] <Issue> As described above, in the electric roller 1, the tilt of the forward / reverse lever 17 is input to the control unit 3, and the control unit 3 outputs a drive command value for acceleration, deceleration, or stop to each inverter J. Each inverter J that has received the drive command value from the control unit 3 accelerates or decelerates according to the input amount of the forward / reverse lever 17, and controls the running operation of the vehicle by outputting a drive command value for the number of rotations to the electric motor for the roller wheel.

[0098] However, the above-described embodiment has a problem in that the vehicle behavior is unstable during acceleration, deceleration, or stopping. For example, when the forward / reverse lever 17 is operated at full throttle in the forward direction during acceleration, the drive command value input to the inverter J rises suddenly from 0 RPM to the target drive command value. At this time, the output of the electric motor for the compaction wheels is small, so the inertial force generated during acceleration cannot be suppressed. As a result, the rotation speed of the electric motor for the compaction wheels exceeds the target drive command value due to the inertia that cannot be fully controlled.

[0099] On the other hand, when decelerating or stopping, the electric motor for the roller wheels is controlled to decelerate by applying regenerative motion and reverse braking. When the forward / reverse lever 17 is returned from full throttle to the neutral position during deceleration or stopping, the drive command value output to the electric motor for the roller wheels drops sharply to 0 rotations. The braking torque generated at this time cannot be fully controlled due to insufficient output from the electric motor for the roller wheels, so a return swing occurs at the time of stopping, equivalent to the braking torque that could not be fully controlled.

[0100] These problems will be explained in more detail. Fig. 21 is a graph showing the relationship between time and engine speed in a comparative example at startup. As shown in Fig. 21, the thin line indicates the input of the forward / reverse lever 17. The forward / reverse lever 17 is, for example, in a state where it is tilted to the maximum in the forward or reverse direction (full throttle state).

[0101] The dotted line indicates the drive command value of the electric motor for the compaction wheels in the comparative example. In other words, it is the drive command value output from the control unit 3 to the inverter for the compaction wheels. In the comparative example shown in FIG. 21 , the target drive command value P1 is approximately 2200 rpm. The point at which the forward / reverse lever 17 is input is defined as the "acceleration command start point W1," the point at which the drive command value of the electric motor for the compaction wheels reaches the target drive command value P1 (the point it reaches in calculation) is defined as the "acceleration command start point N1," and the line connecting the acceleration command start point W1 and the acceleration command target speed reach point N1 is defined as the "first stage acceleration Q1." In the comparative example, for example, the setting is such that the speed rises from 0 rpm to 2200 rpm in approximately 3.0 seconds.

[0102] The thick line indicates the rotation speed (actual rotation speed) of the electric motor for the compaction wheels in the comparative example. The rotation speed of the electric motor for the compaction wheels in the comparative example is lower than the first-stage acceleration Q1, which is the drive command value, immediately after the acceleration-side command start point W1. On the other hand, after reaching the acceleration-side target rotation speed point N1, the inertial force generated during acceleration cannot be suppressed, so the rotation speed of the electric motor for the compaction wheels exceeds the target drive command value P1 for a certain period of time. Furthermore, after slightly falling below the target drive command value P1, the rotation speed of the electric motor for the compaction wheels and the target drive command value P1 become equal. In other words, in this comparative example, after the acceleration-side target rotation speed point N1, the electric motor for the compaction wheels enters an overspeed state for a certain period of time, causing the vehicle behavior to become unstable.

[0103] FIG. 22 is a graph showing the relationship between time and rotation speed in a comparative example when the vehicle is stopped. As shown in FIG. 22, when the vehicle is stopped, the target drive command value P2 is 0 rpm (0 rotations). The point at which the forward / reverse lever 17 is returned from the full throttle state to the neutral position is defined as the "deceleration command start point W2." The point at which the drive command value of the electric motor for the rolling wheels reaches the target drive command value P2 (the point calculated) is defined as the "deceleration command target rotation speed arrival point N2." The line connecting the deceleration command start point W2 and the deceleration command target rotation speed arrival point N2 is defined as the "first stage deceleration Q2." In the comparative example, the setting is such that the vehicle speed decreases from 2,200 rpm to 0 rpm in approximately 2.0 seconds, for example.

[0104] In the comparative example, the rotation speed of the electric motor for the compaction wheels exceeds the drive command value immediately after the deceleration-side command start point W2. However, after the deceleration-side target rotation speed point N2 is reached, the generated braking torque cannot be fully controlled due to insufficient output from the electric motor for the compaction wheels, so the rotation speed of the electric motor for the compaction wheels falls below the target drive command value P2 for a certain period of time. Thereafter, the rotation speed of the electric motor for the compaction wheels and the target drive command value P2 match. In other words, in this comparative example, the electric motor for the compaction wheels enters an overspeed state for a certain period of time after the deceleration-side target rotation speed point N2, causing unstable vehicle behavior (a return movement when stopped).

[0105] <Configuration of over-rotation prevention mechanism for electric motor for rolling wheel - starting side> Figure 23 is a graph showing the drive command value of the electric motor for the rolling wheel of the comparative example and the example as a relationship between time and rotation speed. The solid line shows the drive command value of the electric motor for the rolling wheel of the example. The dotted line shows the drive command value of the electric motor for the rolling wheel of the comparative example.

[0106] As shown by the solid line in Figure 23, at the start of the embodiment, the drive command value for the electric motor for the roller wheels has an acceleration-side shift point U1, and also has a first-stage acceleration Q3 and a second-stage acceleration Q4. The slope (acceleration) of the first-stage acceleration Q3 is larger (steeper) than the slope (acceleration) of the first-stage acceleration Q1 of the comparative example. On the other hand, the slope of the second-stage acceleration Q4 is smaller (gentler) than the slope (first-stage acceleration Q1 of the comparative example.

[0107] Figure 24 is a graph showing the relationship between time and rotation speed at start-up in an embodiment. In Figure 24, the dotted line shows the drive command value of the electric motor for the compaction wheels in the embodiment. The solid line shows the rotation speed of the electric motor for the compaction wheels in the embodiment. In the embodiment as well, the drive command value of the electric motor for the compaction wheels is set so that the target drive command value P1 is 2200 rpm and the target drive command value P1 is reached in 3.0 seconds from the input of the forward / reverse lever 17.

[0108] As shown in FIG. 24 , at the start of the embodiment, the slope of the second-stage acceleration Q4 when approaching the acceleration-side target rotation speed reaching point N1 is smaller (gentler) than the slope of the first-stage acceleration Q1 in the comparative example. More specifically, at the start of the embodiment, the slope of the first-stage acceleration Q3 is larger than the slope of the first-stage acceleration Q1 in the comparative example (see FIG. 23 ), so the rotation speed of the electric motor for the compaction wheels rises more rapidly than in the comparative example. Thereafter, the second-stage acceleration Q4 reaches the target drive command value P1 more slowly than in the comparative example. This allows the electric motor for the compaction wheels to reach the target drive command value P1 without over-rotating (or by reducing the over-rotation). This stabilizes vehicle behavior during acceleration.

[0109] <Configuration of Overspeed Prevention Mechanism for Electric Motor for Rolling Wheel - Stop Side> As shown by the solid line in Figure 23, on the stop side of the embodiment, the drive command value for the electric motor for the rolling wheel has a deceleration-side speed change point U2, and has a first-stage deceleration Q5 and a second-stage deceleration Q6. The slope (deceleration) of the first-stage deceleration Q5 is larger (steeper) than the slope (deceleration) of the first-stage deceleration Q2 of the comparative example. On the other hand, the slope of the second-stage deceleration Q6 is smaller (more gentle) than the slope of the first-stage deceleration Q2 of the comparative example.

[0110] Fig. 25 is a graph showing the relationship between time and rotation speed in an embodiment when the vehicle is stopped. In Fig. 25, the dotted line shows the drive command value of the electric motor for the rolling wheel in the embodiment. The solid line shows the rotation speed of the electric motor for the rolling wheel in the embodiment. In the embodiment, the target drive command value P2 is set to 0 rpm, and is set to reach the target drive command value P2 2.0 seconds after the forward / reverse lever 17 returns to the neutral position.

[0111] As shown in FIG. 25 , when the vehicle is stopped in the example, the slope of the second-stage deceleration Q6 when approaching the deceleration-side target rotation speed reaching point N2 is smaller (more gentle) than the slope of the first-stage deceleration Q2 in the comparative example. More specifically, when the vehicle is stopped in the example, the slope of the first-stage deceleration Q5 is larger than the slope of the first-stage deceleration Q2 in the comparative example (see FIG. 23 ), so the rotation speed of the electric motor for the compaction wheels drops more rapidly than in the comparative example. The target drive command value P2 is then reached more gently at the second-stage deceleration Q6. This allows the electric motor for the compaction wheels to reach the target drive command value P2 without overspeeding (or by reducing the overspeeding). This prevents rebound during deceleration and stabilizes vehicle behavior.

[0112] FIG. 26 is a graph showing the relationship between time and rotation speed of the electric motor for the roller wheels in the modified example. As shown in FIG. 26, the modified example accelerates or decelerates in three stages. As shown by the solid line in FIG. 26, the drive command value of the electric motor for the roller wheels on the starting side in the modified example includes shift points U3 and U4, as well as a first-stage acceleration Q11, a second-stage acceleration Q12, and a third-stage acceleration Q13. The third-stage acceleration Q13 approaches the acceleration-side target rotation speed arrival point N1. The slope of the third-stage acceleration Q13 is smaller (more gentle) than the first-stage acceleration Q1 in the comparative example. This prevents over-rotation of the electric motor for the roller wheels, as in the second embodiment.

[0113] As shown by the solid line in Figure 26, the drive command value for the electric motor for the rolling wheel on the stop side according to the modified example includes speed change points U5 and U6, as well as a first-stage reduction gear Q14, a second-stage reduction gear Q15, and a third-stage reduction gear Q16. The third-stage reduction gear Q16 faces the reduction-side target rotation speed reaching point N2. The slope of the third-stage reduction gear Q16 is smaller (more gentle) than the first-stage reduction gear Q2 in the comparative example. This makes it possible to prevent over-rotation of the electric motor for the rolling wheel, just like the second embodiment. As in the modified example, two or more speed change points may be provided on the start side or the stop side.

[0114] As described above, the over-speed prevention mechanism for the electric motor for the compaction wheels has at least one speed change point in the drive command value for the electric motor for the compaction wheels, and sets the slope approaching the acceleration-side target speed reach point N1 and the deceleration-side target speed reach point N2 to be smaller than the slope in the comparative example. This allows signals to be output to the inverter for the compaction wheels in multiple speed change ranges, making it possible to gradually reach the target speed of the electric motor for the compaction wheels.

[0115] In the over-speed prevention mechanism for the electric motor for the compaction wheel according to this embodiment, when setting the slope of the drive command value toward the acceleration-side target rotation speed reach point N1 and the deceleration-side target rotation speed reach point N2, a reference slope (here, the slope of the first-stage acceleration Q1 and first-stage deceleration Q2 in the comparative example) is set from the acceleration-side target rotation speed reach point N1 and the deceleration-side target rotation speed reach point N2, and the slope is set so as to be smaller (so as to have a gentler angle) than the reference slope. The drive command value for the electric motor for the compaction wheel over-speed prevention mechanism may be set based on a drive command value file that is preset according to the tilt angle of the forward / reverse lever 17. The drive command value file is, for example, a data file in which shift points are preset according to the tilt angle of the forward / reverse lever 17, the target drive command value, the arrival time, etc. The drive command value file is stored in the memory of the control unit 3. The drive command value for the over-speed prevention mechanism for the electric motor for the compaction wheel may also be calculated appropriately by the control unit 3, for example, based on the detected tilt angle of the forward / reverse lever 17.

[0116] [Third embodiment: Mechanism for preventing over-rotation of the vibrating electric motor] Next, a third embodiment of the present invention will be described. The electric roller 1 according to the third embodiment differs from the first embodiment in that it is provided with a mechanism for preventing over-rotation of the vibrating electric motor M4 in the vibration system. The third embodiment will be described mainly focusing on the differences from the first embodiment.

[0117] <Issue> As in the second embodiment, the vibration electric motor M4 also has the vibration generating shaft 130 equipped with the eccentric weight 134, which may result in an over-rotation state relative to the target drive command value when starting and stopping vibration, which may cause the vehicle behavior to become unstable and give the operator OP a sense of discomfort.

[0118] <Configuration of Mechanism for Preventing Over-Rotation of Vibration Electric Motor> The mechanism for preventing over-rotation of the vibration electric motor sets a speed change point in the drive command value output from the control unit 3 to the vibration inverter J4. The method for setting the speed change point is the same as in the second embodiment, so a detailed description will be omitted. The control unit 3 outputs a signal to the vibration inverter J4 in multiple speed change ranges during vibration generation, allowing the vibration electric motor M4 to gradually reach the target rotation speed. As a result, the vibration electric motor M4 gradually reaches the target rotation speed, making it possible to suppress unstable vibration behavior caused by over-rotation.

[0119] Furthermore, when vibration is stopped, the control unit 3 outputs a signal to the vibration inverter J4 in multiple speed ranges to gradually stop the vibration, thereby suppressing the swing-back phenomenon of the vibration generating shaft 130 and enabling the vibration generating shaft 130 to be stopped stably.

[0120] [Fourth embodiment, front wheel, dashboard] Next, an electric roller 1D according to a fourth embodiment of the present invention will be described. This embodiment differs from the first embodiment in the structure of the front wheel R1D, the structure of the dashboard 14D, the provision of multiple modes according to the state of the vehicle, and the provision of a multi-stage transmission control unit 301. In this embodiment, the differences from the first embodiment will be mainly described.

[0121] As shown in FIG. 27 , the front wheels R1D are equipped with rolls 111D, and a front wheel electric motor M1 and a vibration electric motor M4 are installed at both ends of the vehicle in the width direction. The front wheels R1D have longer rolls 111D and shorter vibration generating shafts 130 compared to the structure of the first embodiment. This allows all components, including the front wheel electric motor M1 and the vibration electric motor M4, to be housed inside the rolls 111D. Therefore, when performing compaction work, the rolls 111D can be moved as close as possible to other structures, etc., improving operability. Other structural features of the front wheels R1D are generally the same as those of the first embodiment, and therefore the same reference numerals as those of the first embodiment are used, and a description thereof will be omitted.

[0122] As shown in Figures 28 and 29, in addition to the structure of the first embodiment, the electric roller 1D is equipped with a sprinkler switch 81 for sprinkling water, a liquid agent switch 82 for spraying liquid agent, a vibration H / L switch 83 for changing the vibration frequency, a speed change switch (multi-speed change means) 84 for changing the vehicle's traveling speed in multiple stages, a hazard switch (light) 85, a buzzer switch (alarm) 86, and a headlight switch (light) 87.

[0123] As shown in FIG. 29, on the top surface of the dashboard 14D, a water sprinkler switch 81, a liquid agent switch 82, a vibration H / L switch 83, a speed change switch 84, a hazard switch 85, a buzzer switch 86, a headlight switch 87, a parking switch 37, and a vibration switch 39 are provided around the display (e.g., an LCD display) 18.

[0124] The water sprinkler switch 81 is electrically connected to the control unit 3D and is a switch that controls the water sprinkler unit (not shown) to start or stop water sprinkling. When the water sprinkler switch 81 is turned ON, water is sprinkled onto the roll 111D via the control unit 3D and the water sprinkler unit (not shown), and when the water sprinkler switch 81 is turned OFF, water sprinkling stops.

[0125] The liquid agent switch 82 is electrically connected to the control unit 3D and is a switch that starts or stops the spraying of the liquid agent via a liquid agent spraying unit (not shown). When the liquid agent switch 82 is turned ON, the liquid agent is sprayed onto the roll 111D via the control unit 3D and the liquid agent spraying unit (not shown), and when the liquid agent switch 82 is turned OFF, the spraying of the liquid agent is stopped.

[0126] The vibration H / L switch 83 is electrically connected to the control unit 3D, operates in conjunction with the vibration switch 39, and is a switch for selecting either the high-speed vibration mode or the low-speed vibration mode. The high-speed vibration mode is a mode in which the vibration electric motor M4 rotates at high speed to increase the vibrating force, and the low-speed vibration mode is a mode in which the vibration electric motor M4 rotates at low speed to decrease the vibrating force. When the vibration H / L switch 83 is set to the high-speed vibration mode side, a high-speed vibration mode signal is sent to the vibration inverter J4. On the other hand, when the vibration H / L switch 83 is set to the low-speed vibration mode side, a low-speed vibration mode signal is sent to the vibration inverter J4.

[0127] The speed change switch 84 is electrically connected to the control unit 3D and is a switch for changing the vehicle's traveling speed among a plurality of gears. In the first embodiment, two speeds could be selected with the traveling H / L switch 36, but in this embodiment, a multi-speed structure of three or more speeds is used. This point will be described in detail later.

[0128] The hazard switch 85 is a switch that turns the hazard warning lamps on or off. The buzzer switch 86 is a switch that turns the alarm 41 that outputs an alarm sound on or off. The headlight switch 87 is a switch that turns the headlights on or off. The headlights can be set to high beam or low beam. The hazard switch 85, buzzer switch 86, and headlight switch 87 are also electrically connected to the control unit 3D, and each operation can be controlled and managed.

[0129] The operating status of each switch may be displayed at any time on the display 18. In the first embodiment described above, the electric hydraulic pump 52 is powered by the 24V battery K2, but it may also be powered by the 48V battery K1 as in this embodiment shown in FIG.

[0130] In addition, the electric roller 1D (control unit 3D) according to this embodiment has five basic control modes for the running state of the electric roller 1D: "switch-off mode," "standby mode," "ready mode," "run mode," and "charge mode," as well as "torque-up mode" and "charge-while-running mode."

[0131] These modes can be switched by the operator OP operating the starter switch 38 (number of times, time, etc.) or by a specific input operation (including operation of the starter switch 38). The starter switch 38 corresponds to a key cylinder that is operated by inserting an ignition key in a vehicle powered by an internal combustion engine, i.e., an engine vehicle. The control unit 3D can, for example, display these modes (excluding the switch-off mode) on the display 18. This allows the operator OP to understand the state (mode) of the vehicle.

[0132] <Switch-off mode> The control unit 3D enters switch-off mode when the starter switch 38 is in the switched-off state. Switch-off mode corresponds to a state in which the ignition key is removed from the key cylinder in an engine vehicle. In switch-off mode, the power is turned off (the control unit (VCU) 3D is also not activated), so the electric roller 1D is unable to travel. Energy consumption in switch-off mode (power consumption of the 48V battery K1 and the 24V battery K2) is zero. In switch-off mode, the forward / reverse lever 17 is set to the neutral position by the operator OP, and the parking switch 37 is set to ON by the operator OP (i.e., the parking brake is activated).

[0133] <Standby Mode> The control unit 3D enters standby mode when the starter switch 38 is activated from switch-off mode. Standby mode is a mode in which the vehicle is in a standby state before traveling. Standby mode corresponds to a state in an engine vehicle in which the main switch is turned on and power can be supplied to electrical components (such as a display) by turning the ignition key one step while it is inserted in the key cylinder. In standby mode, the control unit 3D is activated by power supplied from the 12V battery K3 (lead-acid battery). However, the control unit 3D does not activate the inverter J (inverter for the rolling wheels), so the electric roller 1D is unable to travel. Energy consumption in standby mode (power consumption of the 48V battery K1 and the 24V battery K2) is zero. The ready mode, described below, may be configured to automatically switch to standby mode under certain conditions (for example, if no operation is performed for a long period of time during ready mode).

[0134] <Ready Mode> The control unit 3D switches from standby mode to ready mode when the operator OP operates the starter switch 38 (number of times, time, etc.) or performs a specific input operation. The ready mode corresponds to the state in an engine vehicle in which the engine is started by turning the ignition key one step further from the standby state. In other words, in ready mode, the inverter J is activated under the control of the control unit 3D (the forward / reverse lever 17 is in the neutral position), and the electric roller 1D is ready to travel. The amount of energy consumed in ready mode (the amount of power consumed by the 48V battery K1 and the 24V battery K2) is very small.

[0135] <Run Mode> The control unit 3D switches from ready mode to run mode when the forward / reverse lever 17 is operated to set it to the forward or reverse position. That is, the run mode is switched to by tilting the forward / reverse lever 17, and the vehicle enters a traveling state. Tilting the forward / reverse lever 17 drives the electric motor M, and when the torque of the electric motor M exceeds a predetermined value, the parking brake (de-excited brake 62) is automatically released, and the electric roller 1D starts traveling. Energy consumption in run mode (power consumption of the 48V battery K1 and the 24V battery K2) varies depending on the traveling speed, traveling distance, etc. Note that the operator OP may manually release the parking brake, and then tilt the forward / reverse lever 17 to start the electric roller 1D traveling.

[0136] <Charging Mode (Normal Charging Mode)> In the switch-off mode, the control unit 3D switches from the switch-off mode to the charging mode in response to a specific input operation by the operator OP (for example, connecting a charging terminal (charging cable)). In the charging mode, the control unit 3D executes charging by allowing charging of the 48V battery K1 and the 24V battery K2 from a charging power source or a charging battery. Here, the charging battery may be an external power source or a battery that can be mounted on the electric roller 1D.

[0137] <Torque-Up Mode> When a specific input operation is performed in the ready mode, the control unit 3D switches from the ready mode to the torque-up mode. In the torque-up mode, the control unit 3D temporarily increases the upper limit of the torque output of the inverter J.

[0138] <Charge-while-traveling mode> When a specific input operation is performed while the controller 3D is in the ready mode, the controller 3D switches from the ready mode to the charge-while-traveling mode. In the charge-while-traveling mode, the controller 3D allows the charging of the 48V battery K1 and the 24V battery K2 from the charging battery K4 while the vehicle is traveling. Here, the charging battery K4 can be loaded onto the electric roller 1D and does not interfere with the traveling of the electric roller 1D. In the charge-while-traveling mode, the controller 3D can cause the vehicle to travel when the forward / reverse lever 17 is operated to the forward or reverse position. Furthermore, in the charge-while-traveling mode, the controller 3D activates the electric motor M to enable the electric roller 1D to travel. Note that when the charging rates of the 48V battery K1 and the 24V battery K2 in the charging mode are equal to or higher than a predetermined charging rate (for example, full charge (SoC: 100%)) or when a predetermined input operation (disconnection of the charging terminals 91, 92 (charging cables)) is performed, the control unit 3D ends the charging mode and switches from the charging mode to ready mode or simple run mode. Here, the control unit 3D obtains the charging rates of the 48V battery K1 and the 24V battery K2 detected and calculated by the BMU 71 and uses them for determination.

[0139] [Fourth Embodiment: Multi-Stage Transmission Control Unit] In addition to the structure of the first embodiment, the control unit 3D of the electric roller 1D includes a multi-stage transmission control unit 301 that changes the vehicle's traveling speed in multiple stages. This multi-stage transmission control unit 301 is configured to include a speed change switch 84, a control unit (VCU) 3D, and a display 18 (see FIG. 30 ).

[0140] The speed change switch 84 is a general type of momentary switch, including, for example, a momentary dial switch, a momentary toggle switch, a momentary push switch (up △, down △), a momentary rocker switch, etc. In the present embodiment, the following description will be given assuming that a momentary dial switch is used as the speed change switch 84, but the present invention is not limited to this.

[0141] For example, this momentary dial switch has an operating handle 303 (see Figure 29) that can be held by an operator OP, and is configured so that the operating handle 303 can be rotated one step in the rightward (clockwise) direction and one step in the leftward (counterclockwise) direction by the operator OP's switch input operation.

[0142] When the operating handle 303 is operated in a right-handed (clockwise) direction, the speed change switch 84 is set to input 1 (see step S1 described later) which increases the gear step. On the other hand, conversely, when the operating handle 303 is operated in a left-handed (counterclockwise) direction, the speed change switch 84 is set to input 2 (see step S5 described later) which decreases the gear step. For example, a switch input operation in a right-handed (clockwise) direction of the operating handle 303 increases the gear step by one step, and a switch input operation in a left-handed (counterclockwise) direction of the operating handle 303 decreases the gear step by one step. Note that the gear step may not only increase or decrease by one step, but may also be continuously increased or decreased by a switch input operation of the operating handle 303 continued for a predetermined time.

[0143] This momentary dial switch is initially set to five steps, and then five steps up and four steps down, for a total of ten steps, so that the vehicle's running speed can be changed in 10 steps in increments of 1 km / h.

[0144] More specifically, for example, when the momentary dial switch is set to the 10th position and the forward / reverse lever 17 is at full throttle, the vehicle will travel at 10 km / h. The acceleration up to 10 km / h is determined in advance by an acceleration map stored in the control unit 3D, and is determined in advance so as to avoid damaging the road surface and to achieve optimal energy consumption, for example. For example, if the momentary dial switch is set to the 10th position and the forward / reverse lever 17 is tilted only halfway or one-quarter, fine adjustment of the traveling speed is also possible. An acceleration map for when the forward / reverse lever 17 is not fully tilted is also determined in advance.

[0145] The gear position set by the gear change switch 84 is input as a switch signal to the control unit 3D. Furthermore, the gear position set by the gear change switch 84 is displayed on the display 18 by inputting a display signal from the control unit 3D to the display 18 (see FIG. 30).

[0146] Next, the multi-stage speed change control of the control unit 3D will be described in detail below with reference to Fig. 31. Fig. 31 is a flowchart showing the multi-stage speed change control by the speed change switch.

[0147] First, the control unit 3D determines whether the switch position of the speed change switch 84 is at input 1 (step S1). The determination of whether the switch position is at input 1 is made based on whether the switch input operation of the speed change switch 84 is being rotated in the right direction (clockwise direction). When the control unit 3D determines that the switch operation of the speed change switch 84 is being rotated in the right direction (clockwise direction) (Yes in step S1), the control unit 3D proceeds to step S2.

[0148] In step S2, the control unit 3D checks the gear position n of the gear change switch 84. In this embodiment, the gear position n is set to a natural number between 1 and 10, but is not limited to this.

[0149] Next, the control unit 3D determines whether the gear position n confirmed in step S2 is smaller than MAX (step S3). If it is determined in step S3 that the gear position n is smaller than MAX (Yes in step S3), the control unit 3D proceeds to step S4. If it is determined in step S3 that the gear position n is not smaller than MAX (gear position n=MAX) (No in step S3), the process ends.

[0150] In step S4, the control unit 3D increases the gear n of the gear change switch 84 by one step (n+1), and then ends the process.

[0151] Next, a case will be described where the switch position of the speed change switch 84 is not at input 1 (No in step S1). If the switch position of the speed change switch 84 is not at input 1 in step S1, the process proceeds to step S5.

[0152] In step S5, the control unit 3D determines whether the switch position of the speed change switch 84 is at input 2. Whether the switch position is at input 2 is determined by whether the switch input operation of the speed change switch 84 is rotated in the leftward direction (counterclockwise direction). If the control unit 3D determines that the switch input operation of the speed change switch 84 is rotated in the leftward direction (counterclockwise direction) (Yes in step S5), the control unit 3D proceeds to step S6. Conversely, if the control unit 3D determines that the switch input operation of the speed change switch 84 is not rotated in the leftward direction (counterclockwise direction) (No in step S5), the control unit 3D ends the processing.

[0153] In step S6, the control unit 3D checks the gear position n of the gear change switch 84. Next, the control unit 3D determines whether the gear position n checked in step S6 is greater than 1 (step S7). In step S7, if it is determined that the gear position n is greater than 1 (Yes in step S7), the control unit 3D proceeds to step S8. Conversely, if it is determined that the gear position n is 1 (No in step S7), the control unit 3D ends the process.

[0154] In step S8, the control unit 3D decreases the gear n of the gear change switch 84 by one step (n-1), and then ends the process.

[0155] Next, the control of the vehicle acceleration in accordance with the gear position of the speed change switch 84 will be described in detail below with reference to Fig. 32. Fig. 32 is a flowchart showing the control of the vehicle acceleration.

[0156] First, the control unit 3D determines whether the operator OP has tilted the forward / reverse lever 17 to input the forward / reverse lever 17 (step S11). When the control unit 3D determines that the operator OP has tilted the forward / reverse lever 17 to input the forward / reverse lever 17 (Yes in step S11), the control unit 3D proceeds to step S12.

[0157] In step S12, the control unit 3D checks the gear position n of the gear change switch 84. Setting of this gear position of the gear change switch 84 is performed by the processing steps shown in Figure 31. In this embodiment, the gear position is set to n = a natural number from 1 to 10.

[0158] Next, the control unit 3D determines whether the gear position is 1 (n=1) (step S13). If it is determined that the gear position is 1 (Yes in step S13), the control unit 3D applies acceleration map 1 stored in advance in the storage unit of the control unit 3D and ends the process (step S14).

[0159] In step S13, if it is determined that the gear is not in first gear (n=1) (No in step S13), the process proceeds to step S15. In step S15, it is determined whether the gear is in second gear (n=2). If it is determined that the gear is in second gear (n=2) (Yes in step S15), the acceleration map 2 stored in advance in the memory unit of the control unit 3D is applied, and the process ends (step S16).

[0160] In step S15, if it is determined that the gear is not in second gear (No in step S15), the process proceeds to the next step. In the next step, it is determined whether the gear is in third gear (n=3). If it is determined that the gear is in third gear (Yes in the next step), acceleration map 3 is applied and the process ends.

[0161] If it is determined in the next step that the gear is not in third gear, the process proceeds to the next step. In the next step, it is determined whether the gear is in fourth gear (n=4). If it is determined that the gear is in fourth gear, acceleration map 4 is applied and the process ends.

[0162] If it is determined in the next step that the gear is not in fourth gear, the process proceeds to the next step. In the next step, it is determined whether the gear is in fifth gear (n=5). If it is determined that the gear is in fifth gear, acceleration map 5 is applied and the process ends.

[0163] In the above-described order, it is determined whether the gear is set to 6, and if it is determined that the gear is set to 6, the acceleration map 6 is applied and the processing is terminated. In this way, the control unit 3D increases the gear by one step (7th step → 8th step → 9th step), and finally, the gear is set to 10th step (n=10, MAX) (step S17), and the acceleration map 10 is applied and the processing is terminated (step S18).

[0164] As described above, in this embodiment, the acceleration of the vehicle is controlled by applying an acceleration map n corresponding to the gear n set by the input operation of the gear change switch 84. This acceleration map is preset in the storage unit of the control unit 3D, and the acceleration of the vehicle increases or decreases as the gear is increased or decreased. Furthermore, this acceleration map is set taking into account the existence of an ideal energy consumption for reaching a set speed in the same amount of time.

[0165] In this embodiment, the control unit 3D outputs a motor rotation speed command value to the inverter J from a predetermined acceleration map n based on the input amount (tilt angle) of the forward / reverse lever 17 and the gear set by the gear change switch 84, thereby controlling the vehicle's running speed in multiple stages.

[0166] According to the present embodiment described above, electrification can substantially eliminate fuel consumption and greenhouse gas emissions. Furthermore, electrification can reduce noise and substantially eliminate greenhouse gas emissions, thereby reducing the burden on operators and improving the working environment. Furthermore, there is no need to change hydraulic oil, resulting in excellent maintainability. Furthermore, the inclusion of an inverter for the roller wheels makes speed control easy.

[0167] Furthermore, according to this embodiment, the provision of the speed change switch 84 allows for easy multi-stage control of the vehicle's gears. This makes it possible to effectively prevent differences in compaction work speed that occur depending on the operator's operating technique or on each site. As a result, this embodiment makes it possible to stabilize the construction quality of the compacted road surface.

[0168] Furthermore, according to this embodiment, multi-stage vehicle travel control simplifies vehicle speed adjustment using the forward / reverse lever 17. As a result, this embodiment eliminates variations in construction quality depending on the operator OP, and achieves improved and stable construction road surface quality.

[0169] Furthermore, according to this embodiment, by accelerating the vehicle at a jerk corresponding to the gear set by the gear change switch 84, energy consumption can be reduced and the construction time can be improved.

[0170] Furthermore, in this embodiment, it is preferable that the speed change switch 84 is configured by a momentary switch. By using a momentary switch, it can be configured inexpensively and simply.

[0171] Furthermore, according to this embodiment, the shift switch 84 (momentary switch) is configured so that a switch input operation in a predetermined direction increases the gear step by one step, and a switch input operation in the opposite predetermined direction decreases the gear step by one step, thereby enabling simple multi-stage control of the vehicle's gear steps.

[0172] Furthermore, according to this embodiment, the speed change switch 84 (momentary switch) is configured so that the gear position not only increases or decreases one gear at a time, but also continues to increase or decrease the gear position by a switch input operation of the operating handle 303 that continues for a predetermined time. For example, by continuing to rotate the operating handle 303 clockwise for a predetermined time, the gear position can be set from, for example, 5th gear to 10th gear. This allows the gear position to be changed quickly and easily in this embodiment.

[0173] Fifth Embodiment Electric Brake Control in Vehicle Emergency, etc. Overview of Brake System of Electric Roller First, an overview of each brake in an electric roller according to an embodiment of the present invention will be described based on the table shown in FIG.

[0174] Brakes are broadly divided into "service brakes" and "parking brakes." "Service brakes" are electric brakes designed to slow down the vehicle. Electric brakes use an electric motor to generate a counter torque in the direction of travel, thereby slowing the vehicle.

[0175] A parking brake is made up of an electric brake that keeps the vehicle stopped, and a mechanical brake that also keeps the vehicle stopped. The electric brake uses an electric motor to control the number of rotations of the roll and roller wheels to zero, thereby keeping the vehicle stopped. Note that energy is consumed while the electric brake is keeping the vehicle stopped. The mechanical brake is a negative brake that keeps the vehicle stopped when not energized.

[0176] Next, the braking flow in the electric roller according to this embodiment will be described with reference to the block diagram shown in FIG.

[0177] The operator OP issues a command to stop the vehicle (A1). The operator OP operates the forward / reverse lever 17 to the neutral (N) position. Next, the electric brake, which is the service brake, is activated to decelerate and stop the vehicle (A2). Furthermore, the electric brake, which is the parking brake, is activated to hold the vehicle at a stop (holding at 0 rotations) (A3). After a predetermined time has elapsed since the vehicle was held at a stop, the control unit 3 activates the mechanical brake to hold the vehicle at a stop (A4). Because the mechanical brake is activated to hold the vehicle at a stop, from the perspective of energy consumption efficiency, power supply to the electric brake is stopped and the zero rotation holding of the electric brake is released. As a result, the electric brake enters a motor-free state (A5).

[0178] <Issue> Conventionally, there is no system to determine whether the braking force of the mechanical brake is operating normally, so if the braking force of the mechanical brake is not normal, there is a risk that the vehicle will move due to the operation of the operator OP.

[0179] Furthermore, if the mechanical brakes lose their braking force due to a malfunction, there is a problem in that the electric brakes are released when the power supply to the electric brakes is cut off, and there is no way to keep the vehicle stopped.

[0180] Therefore, the object of this embodiment is to provide an electric roller that allows the vehicle to automatically check the braking state of the mechanical brake when the vehicle starts to move and when the vehicle stops moving, and that can automatically keep the vehicle stopped using the electric brake if the braking force of the mechanical brake is no longer effective.

[0181] <Electric Brake Control When Vehicle Starts Running> Next, control of the electric brake when the vehicle starts running will be described below with reference to the block diagram shown in FIG. 35 and the flowchart shown in FIG.

[0182] 35, first, when the vehicle starts to travel, the vehicle operator OP operates the forward / reverse lever 17 to instruct the vehicle to travel (forward / reverse) (B1). Based on this instruction from the operator OP, the control unit 3 outputs control signals instructing the motor rotation speeds to the front wheel inverter J1, the right rear wheel inverter J2, and the left rear wheel inverter J3, respectively (B2).

[0183] Next, the control unit 3 outputs a braking force confirmation signal to confirm the braking force of the non-excitation brake 62 (hereinafter referred to as the mechanical brake 62) to the rear right wheel inverter J2 and the rear left wheel inverter J3 (B3), thereby starting the electric brake control mode at the start of driving shown in Figure 36.

[0184] 36, the control unit 3 determines whether or not the mechanical brake 62 is in the "ON state" (step S21). If the mechanical brake 62 is in the "ON state" (Yes in step S21), the process proceeds to step S22, and if the mechanical brake 62 is in the "OFF state" (No in step S21), the process returns to step S21 again.

[0185] In step S22, the control unit 3 (mechanical brake state determination means 400 (see FIGS. 4 and 28)) determines whether the motor torque (vehicle start-up torque) of either the right rear wheel electric motor M2 or the left rear wheel electric motor M3 is equal to or greater than a predetermined value X (Nm) when the electric motors are rotating (when the motors start to rotate). This motor torque is detected by a function provided in either the right rear wheel inverter J2 or the left rear wheel inverter J3, and the detection signal is output to the control unit 3. Note that the motor torque of the electric motor may also be detected by a function provided in the inverter (for example, a torque sensor, not shown).

[0186] That is, the control unit 3 includes a mechanical brake state determination means 400 that automatically determines the state of the mechanical brake 62 when the vehicle starts to move (when the vehicle starts to move from a stopped state) (see FIGS. 4 and 28). With the mechanical brake 62 in an on state, the mechanical brake state determination means 400 determines whether the motor torque (driving torque) of at least one of the right rear wheel electric motor M2 and the left rear wheel electric motor M3 is equal to or greater than a predetermined value when the right rear wheel electric motor M2 and the left rear wheel electric motor M3 start to rotate, thereby determining whether the mechanical brake 62 is exerting a braking force. The reason for determining whether the mechanical brake 62 is exerting a braking force based on the motor torque (driving torque) of the electric motor when the vehicle starts to move from a stopped state is that the presence or absence of the braking force of the mechanical brake 62 cannot be determined based on the rotational speed of the electric motor. Regardless of whether the mechanical brake 62 is exerting a braking force, the rotational speed of the electric motor increases from 0 when the vehicle starts to move.

[0187] If the motor torque of either electric motor is equal to or greater than the predetermined value X (Nm) (Yes in step S22), the process proceeds to step S23, but if the motor torque of at least one of the electric motors is less than the predetermined value X (Nm) (No in step S22), the control unit 3 assumes that the mechanical brake 62 has failed or been damaged, and proceeds to step S25, which will be described later.In this embodiment, as shown in Figures 14 and 15, the right rear wheel electric motor M2 and the left rear wheel electric motor M3 are connected by a single shaft, and therefore it is sufficient to detect the motor torque of at least one of the two electric motors.

[0188] In step S23, since it is confirmed that there is no problem with the braking force of the mechanical brake 62, normal driving control is performed. Next, the control unit 3 determines whether the vehicle power is currently off (step S24). If the vehicle power is currently off, the electric brake control mode at the start of driving is terminated. If the vehicle power is currently on, the process returns to the initial step S21.

[0189] Next, in step S22, if the motor torque of either of the two electric motors (the right rear wheel electric motor M2 and the left rear wheel electric motor M3) is less than the predetermined value X (Nm) (No in step S22), the control unit 3 (mechanical brake state determination means 400) determines that the mechanical brake 62 is malfunctioning or damaged because the drive torque of the electric motor is less than the predetermined value. Next, the control unit 3 outputs an ON signal to the electromagnetic brake 61 (hereinafter referred to as the electric brake 61) to activate the electric brake 61, thereby starting to hold the rear wheel R2 of the vehicle at zero rotation (step S25). In other words, in this embodiment, if the motor torque of at least one of the two electric motors (the right rear wheel electric motor M2 and the left rear wheel electric motor M3) is less than the predetermined value X (Nm), the control unit 3 determines that the mechanical brake 62 is malfunctioning or damaged, and starts zero rotation hold control by the electric brake 61.

[0190] Next, in step S26, the control unit 3 prevents the vehicle power supply from being turned off by operating the starter switch 38 (see FIG. 6). That is, the control unit 3 controls the vehicle power supply so that it is not turned off even when the operator OP operates the starter switch 38 to switch it off. This is because, normally, when the starter switch 38 is switched off, the vehicle power supply is turned off, making it impossible for the electric brake 61 to hold the vehicle stopped.

[0191] Next, the control unit 3 issues a mechanical brake error alarm (step S27). When a mechanical brake error alarm is issued, the control unit 3 activates the electric brake 61 to stop the vehicle and notifies the operator OP of the error condition by issuing an alarm and displaying the error on the display. Furthermore, when a mechanical brake error occurs, the control unit 3 prevents the vehicle power from being turned off unless a specific operation, such as a mechanical brake error release operation (see step S29) described below, is performed.

[0192] Next, the control unit 3 performs driving control during the mechanical brake error (step S28). During the mechanical brake error, the vehicle can be driven by operating the forward / reverse lever 17, but the control unit 3 sets a limit on the maximum speed at which the vehicle can be driven.

[0193] Next, the control unit 3 determines whether or not the operator OP has input an operation to cancel the mechanical brake error (step S29). If the operator OP has input an operation to cancel the mechanical brake error (Yes in step S29), the control unit 3 ends the electric brake control mode at the start of vehicle travel. On the other hand, if the operator OP has not input an operation to cancel the mechanical brake error (No in step S29), the control unit 3 returns to step S29 again.

[0194] <Electric Brake Control When Vehicle Stops Running> Next, control of the electric brake when the vehicle stops running will be described below with reference to the flowchart shown in FIG.

[0195] First, the control unit 3 determines whether the forward / reverse lever 17 is in the neutral (N) position (step S31). The control unit 3 makes this determination based on a detection signal from the limit switch 32 (see FIG. 4) that detects the neutral position of the forward / reverse lever 17.

[0196] If the forward / reverse lever 17 is not in the neutral (N) position (No in step S31), the control unit 3 controls the front wheel electric motor M1, the right rear wheel electric motor M2, and the left rear wheel electric motor M3 (travel motor control) in accordance with the input amount of the forward / reverse lever 17 (step S32). Note that in this embodiment, the front wheel electric motor M1, the right rear wheel electric motor M2, and the left rear wheel electric motor M3 may all be collectively referred to as the "travel motors."

[0197] On the other hand, in contrast to the above, when the forward / reverse lever 17 is in the neutral (N) position (Yes in step S31), the control unit 3 activates the electric brake 61 to perform deceleration control of the front wheel electric motor M1, the right rear wheel electric motor M2, and the left rear wheel electric motor M3 (step S33).

[0198] Next, the control unit 3 outputs a braking signal to the electric brake 61 to perform zero rotation holding control of the front wheel electric motor M1, the right rear wheel electric motor M2, and the left rear wheel electric motor M3 (step S34).

[0199] Next, the control unit 3 (mechanical brake state determination means 400) determines whether the rotation speeds of the right rear wheel electric motor M2 and the left rear wheel electric motor M3 have each become 0 due to the 0 rotation hold control of the electric brake 61 (step S35). This is detected by rotation sensors (not shown) attached to the right rear wheel electric motor M2 and the left rear wheel electric motor M3, respectively, and the detection signals are output to the control unit 3.

[0200] If the rotation speeds of the right rear wheel electric motor M2 and the left rear wheel electric motor M3 are not 0 (No in step S35), return to step S35 until the rotation speeds of the right rear wheel electric motor M2 and the left rear wheel electric motor M3 become 0.

[0201] Next, when the rotation speeds of the right rear wheel electric motor M2 and the left rear wheel electric motor M3 become 0 (Yes in step S35), the control unit 3 activates the mechanical brake 62 after n seconds to turn on the mechanical brake 62 (step S36). At the same time as turning on the mechanical brake 62, the control unit 3 outputs a 0 rotation hold release signal to the electric brake 61 to release the 0 rotation hold state by the electric brake 61 (step S37).

[0202] Furthermore, the control unit 3 (mechanical brake state determination means 400) determines whether the rotation speeds of the right rear wheel electric motor M2 and the left rear wheel electric motor M3 are each zero due to the braking force of the mechanical brake 62 (step S38). This determination is made based on a detection signal from a rotation sensor (not shown). Note that when the vehicle stops running (when the vehicle stops from a moving state), the presence or absence of braking force from the mechanical brake 62 is determined based on the rotation speed of the electric motor. This is because when the electric motor rotates (operates) under its own weight, it is difficult to determine the motor torque value that is fed back, and therefore the rotation speed of the electric motor, which is reliably fed back, is used as the determination criterion.

[0203] In step S38, if the rotation speeds of the right rear wheel electric motor M2 and the left rear wheel electric motor M3 are not 0 (No in step S38), the control unit 3 (mechanical brake state determination means 400) determines that the mechanical brake 62 has failed or been damaged and does not have the required braking force, and activates the electric brake 61 again to start 0 rotation maintenance control (step S39).

[0204] Next, in step S40, the control unit 3 prevents the vehicle power supply from being turned off by operating the starter switch 38 (see FIG. 6). That is, the control unit 3 controls the vehicle power supply so that it is not turned off even when the operator OP operates the starter switch 38 to switch it off. This is because, normally, when the starter switch 38 is switched off, the vehicle power supply is turned off, making it impossible for the electric brake 61 to hold the vehicle stopped.

[0205] Next, the control unit 3 issues a mechanical brake error alarm (step S41). When a mechanical brake error alarm is issued, the control unit 3 activates the electric brake 61 to stop the vehicle and notifies the operator OP of the error condition by issuing an alarm and displaying the error on the display. Furthermore, when a mechanical brake error occurs, the control unit 3 prevents the vehicle power from being turned off unless a specific operation, such as a mechanical brake error release operation (see step S43) described below, is performed.

[0206] Next, the control unit 3 performs driving control during the mechanical brake error (step S42). During the mechanical brake error, the vehicle can be driven by operating the forward / reverse lever 17, but the control unit 3 sets a limit on the maximum speed at which the vehicle can be driven.

[0207] Next, the control unit 3 determines whether the operator OP has input an operation to cancel the mechanical brake error and the vehicle's power supply has been turned off (step S43). If the operator OP has input an operation to cancel the mechanical brake error and the vehicle's power supply has been turned off (Yes in step S43), the control unit 3 ends the electric brake control mode when the vehicle is stopped. On the other hand, if the operator OP has not input an operation to cancel the mechanical brake error, the control unit 3 returns to step S43 again.

[0208] In step S38, if the control unit 3 determines that the rotation speeds of the electric motor M2 for the right rear wheel and the electric motor M3 for the left rear wheel are each 0 (Yes in step S38), it determines that the braking force of the mechanical brake 62 is operating normally.

[0209] Next, the control unit 3 determines whether the vehicle power supply has been turned off by the operation of the operator OP (step S44). This is determined by whether the starter switch 38 has been turned off by the operation of the operator OP. If the vehicle power supply has been turned off (Yes in step S44), the electric brake control mode when the vehicle is stopped is terminated. On the other hand, if the vehicle power supply is still on (No in step S44), the process returns to step S31 again.

[0210] <Effects of this embodiment> This embodiment has an electric brake 61 that outputs a zero rotation signal to the right rear wheel inverter J2 and the left rear wheel inverter J3 when the forward / reverse lever 17 is in neutral to slow down or stop the vehicle, and a mechanical brake 62 that mechanically holds the vehicle stopped.

[0211] The control unit 3 includes a mechanical brake state determination means 400 that automatically determines the state of the mechanical brake 62 when the vehicle starts to move (when the vehicle starts to move from a stopped state) and when the vehicle stops to move (when the vehicle stops to move) (see FIGS. 4 and 28). The mechanical brake state determination means 400 includes an electric brake control mode when the vehicle starts to move (see FIG. 36) and an electric brake control mode when the vehicle stops to move (see FIG. 37).

[0212] In the electric brake control mode when the vehicle starts to travel, with the mechanical brake 62 in the ON state, when the right rear wheel electric motor M2 and the left rear wheel electric motor M3 start to rotate, the presence or absence of braking force of the mechanical brake 62 is determined by determining whether the motor torque (driving torque) of the right rear wheel electric motor M2 and the left rear wheel electric motor M3 is equal to or greater than a predetermined value, and if so, the control unit 3 (mechanical brake state determination means 400) turns on the electric brake 61 to stop and hold the vehicle.

[0213] In the electric brake control mode when the vehicle is stopped, the electric brake 61 is first activated to control the running electric motor to maintain zero rotations, and then the mechanical brake 62 is activated. After that, when the zero rotation hold control of the electric brake 61 is released, it is determined whether the number of rotations of the running electric motor is zero, thereby determining whether the mechanical brake 62 is exerting braking force. If it is determined that the braking force of the mechanical brake 62 is not exerted, the control unit 3 (mechanical brake state determination means 400) turns the electric brake 61 on again to maintain the vehicle at a stop. In the electric brake control mode when the vehicle is stopped, for example, when the vehicle is stopped halfway up a slope, such as an uphill or downhill slope, if the mechanical brake 62 malfunctions or is damaged, the vehicle may move under its own weight. However, in this embodiment, even in such a state, the control unit 3 activates the electric brake 61 to start the zero rotation hold control, thereby preventing the vehicle from moving (moving) under its own weight.

[0214] In this embodiment, even if a serious error occurs that causes the braking force of the mechanical brake 62 to become ineffective, the vehicle can be maintained in a stopped state by controlling the electric brake 61, thereby improving the braking force of the brake system.

[0215] Furthermore, in this embodiment, the timing for detecting the braking force of the mechanical brake 62 is when the vehicle starts moving from a stopped state and when the vehicle stops from a moving state, thereby preventing the vehicle from running without the braking force of the mechanical brake 62 being effective, and further improving the braking force of the brake system.

[0216] Furthermore, in this embodiment, even if a mechanical brake error occurs, the vehicle can be allowed to travel with restrictions (for example, a limit on the maximum traveling speed), making it possible to evacuate the vehicle to a safe area, thereby improving the convenience of the vehicle.

[0217] Furthermore, in this embodiment, when it is determined that there is no braking force in the braking force assessment of the mechanical brake 62, the control unit 3 controls the vehicle power supply to be switched from the ON state to the OFF state only when an error reset operation is input. That is, in this embodiment, the control unit 3 controls the vehicle power supply so that it will not be switched OFF when a mechanical brake error occurs unless the operator OP performs a specific operation (for example, an error reset operation). As a result, in this embodiment, even if the operator OP reflexively switches the vehicle power supply OFF when a mechanical brake error occurs, the vehicle's stopped state maintained by the electric brake 61 will not be released, and the braking force of the brake system can be further improved.

[0218] Furthermore, in this embodiment, when it is determined that there is no braking force in the braking force determination of the mechanical brake 62, the control unit 3 issues an error alarm and displays an error on the display 18. This makes it possible to notify the operator OP of the error condition.

[0219] Although the embodiment of the present invention has been described above, appropriate design changes are possible within the scope of the present invention.

[0220] 1 Electric roller 3, 3D control unit 17 Forward / reverse lever 61 Excited brake (electric brake) 62 Non-excited brake (mechanical brake) 400 Mechanical brake state determination means M1 Front wheel electric motor M2 Right rear wheel electric motor M3 Left rear wheel electric motor R1 Front wheel (rolling wheel) R2 Rear wheel (rolling wheel)

Claims

1. An electric roller comprising: a pair of compaction wheels installed at the front and rear, respectively; a body frame rotatably supporting the compaction wheels; an electric motor for driving the compaction wheels; a compaction wheel inverter controlling the rotation speed of the electric motor for the compaction wheels; a battery supplying power to the electric motor for the compaction wheels and the compaction wheel inverter; a control unit outputting a signal to the compaction wheel inverter in accordance with the tilt of a forward / reverse lever; an electric brake which, when the forward / reverse lever is neutral, outputs a zero rotation signal to the compaction wheel inverter to slow down or stop the vehicle; and a mechanical brake which mechanically holds the vehicle in a stopped state; wherein the electric roller does not have an internal combustion engine, and the battery is the only power source for the compaction wheels; and the control unit is equipped with mechanical brake state determination means for automatically determining the state of the mechanical brake at least when the vehicle starts to move or when it stops moving.

2. An electric roller according to claim 1, wherein when the vehicle starts moving from a stopped state, the mechanical brake state determination means determines whether the torque of the electric motor for the rolling wheel is equal to or greater than a predetermined value when the mechanical brake is in the on state, thereby determining whether the mechanical brake has braking force.

3. An electric roller according to claim 2, wherein when the braking force of the mechanical brake is judged to be insufficient, the electric brake is turned on to stop and hold the vehicle.

4. An electric roller according to claim 3, wherein when it is determined that there is no braking force in the braking force judgment of the mechanical brake, at least one of issuing an alarm and displaying the information on the display means of the vehicle is performed.

5. An electric roller according to claim 3, characterized in that when the braking force of the mechanical brake is judged to be insufficient, the vehicle power supply is switched from an on state to an off state only when an error release operation is input.

6. An electric roller according to claim 1, characterized in that when the vehicle stops from a moving state, the mechanical brake state determination means determines whether the number of rotations of the electric motor for the rolling wheel is 0 when the mechanical brake is in the on state, thereby determining whether the mechanical brake has braking force.

7. An electric roller according to claim 6, wherein when the braking force of the mechanical brake is judged to be insufficient, the electric brake is turned on to stop and hold the vehicle.

8. An electric roller according to claim 7, wherein when it is determined that there is no braking force in the braking force judgment of the mechanical brake, at least one of issuing an alarm and displaying the information on the display means of the vehicle is performed.

9. An electric roller according to claim 7, characterized in that when the braking force of the mechanical brake is judged to be insufficient, the vehicle power supply is switched from an on state to an off state only when an error release operation is input.

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