Electric roller

Abstract

This invention provides an electric roller that allows for easy speed and vibration control, contributing to a decarbonized society, improving the working environment, and enhancing maintainability. [Solution] The vehicle comprises a compaction wheel, a vehicle frame, an electric motor for the compaction wheel, an inverter for the compaction wheel, a vibration generating shaft 130 provided inside the compaction wheel and equipped with an eccentric weight, a vibration electric motor M4 that drives the vibration generating shaft 130, a vibration inverter J4 that controls the rotational speed of the vibration electric motor M4, a battery K that supplies power to the electric motor for the compaction wheel, etc., and a control unit 3 that outputs a signal to the vibration inverter J4 in accordance with the operator's operation. The vehicle does not have an internal combustion engine, the power source for the compaction wheel is solely the battery K, the rotational speed of the vibration electric motor M4 is controlled by the vibration inverter J4 in accordance with the operator's operation, and the intensity of the vibration can be adjusted according to the rotational speed.

Description

Technical Field

[0001] The present invention relates to an electric roller.

Background Art

[0002] For example, Patent Document 1 discloses a compaction vehicle (compaction roller) for compacting a road surface. A conventional compaction roller includes a pair of compaction wheels, a vehicle body frame, an engine, a hydraulic pump, and a travel hydraulic motor. The conventional compaction roller drives the hydraulic pump by the engine, and rotates the travel hydraulic motor by the hydraulic pressure to travel. Further, by adjusting the oil discharge force according to the input amount of the forward and reverse lever, the vehicle accelerates, decelerates or stops.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, efforts have been made globally towards a decarbonized society aiming for zero emissions of greenhouse gases that cause global warming. However, in a conventional compaction roller, since an engine is used, fossil fuel is consumed and greenhouse gases such as CO2 are also emitted. Further, since the use of an engine increases noise and exhaust heat, for example, the burden on an operator in an enclosed space such as a tunnel increases, and the adverse impact on the working environment (people, structures, trees, etc.) at the construction site also increases. Furthermore, in a conventional compaction roller, there are problems such as occurrence of hydraulic oil leakage and increase in the frequency of hydraulic oil replacement, resulting in poor maintainability. Also, it is preferable that the compaction roller can easily perform speed control and vibration control of the compaction wheels.

[0005] Therefore, the objective of the present invention is to provide an electric roller that can easily control speed and vibration of the compaction wheel, and that can contribute to a decarbonized society, improve the working environment, and enhance maintainability. [Means for solving the problem]

[0006] The electric roller of the present invention comprises a pair of compaction wheels installed at the front and rear, a vehicle frame that rotatably supports the compaction wheels, an electric motor for compaction wheels that drives the compaction wheels, an inverter for compaction wheels that controls the rotational speed of the electric motor for compaction wheels, a vibration-generating shaft provided inside the compaction wheel and equipped with an eccentric weight, an electric motor for vibration that drives the vibration-generating shaft, an inverter for vibration that controls the rotational speed of the electric motor for vibration, a battery that supplies power to the electric motor for compaction wheels, the inverter for compaction wheels, the electric motor for vibration, and the inverter for vibration, and a control unit that outputs a signal to the inverter for vibration according to the operator's operation. The present invention does not have an internal combustion engine, the power source for the compaction wheels is solely the battery, the rotational speed of the electric motor for vibration is controlled by the inverter for vibration according to the operator's operation, and the intensity of vibration can be adjusted according to the rotational speed.

[0007] Furthermore, the electric roller of the present invention comprises a pair of compaction wheels installed at the front and rear, a vehicle frame that rotatably supports the compaction wheels, an electric motor for compaction wheels that drives the compaction wheels, an inverter for compaction wheels that controls the rotational speed of the electric motor for compaction wheels, a vibration-generating shaft provided inside the compaction wheel and equipped with an eccentric weight, an electric motor for vibration that drives the vibration-generating shaft, an inverter for vibration that controls the rotational speed of the electric motor for vibration, a battery that supplies power to the electric motor for compaction wheels, the inverter for compaction wheels, the electric motor for vibration, and the inverter for vibration, and a control unit that outputs a signal to the inverter for vibration according to the operator's operation, and is characterized in that it does not have an internal combustion engine, the power source for the compaction wheels is the battery alone, the compaction wheels are rotatably supported via vibration-damping rubber provided on a pair of side plates provided on the side of the vehicle frame, and the electric motor for vibration and the inverter for vibration are installed above the springs above the vibration-damping rubber.

[0008] According to the present invention, speed control and vibration control of the compaction wheels can be easily performed, and fuel consumption and greenhouse gas emissions can be substantially eliminated by electrification. Furthermore, since noise can be reduced and greenhouse gas emissions can be substantially eliminated by electrification, the burden on the operator can be reduced and the working environment can be improved. In addition, maintenance is excellent as there is no need to change the hydraulic fluid, etc. Furthermore, according to the present invention, the compaction wheels can be vibrated by electricity.

[0009] Furthermore, it is preferable that the battery comprises multiple batteries with different voltages, and that the batteries supplying power to the compaction wheel electric motor, the compaction wheel inverter, the vibration electric motor, and the vibration inverter are configured separately from the battery supplying power to the starter switch used during starting. [Effects of the Invention]

[0010] According to the present invention, speed control and vibration control of the compaction wheels can be easily performed, and it is possible to contribute to a decarbonized society, improve the working environment, and enhance maintainability. [Brief explanation of the drawing]

[0011] [Figure 1] This is a side view of an electric roller according to the first embodiment of the present invention. [Figure 2] This is a plan view of the electric roller according to the first embodiment. [Figure 3] This is a rear view of the electric roller according to the first embodiment. [Figure 4] This is a block diagram showing the configuration of an electric roller according to the first embodiment. [Figure 5] This is a schematic diagram illustrating the operation of the electric roller according to the first embodiment. [Figure 6] This is a block diagram showing the power supply system and control system of an electric roller according to the first embodiment. [Figure 7] This is a rear view showing the dashboard of the electric roller according to the first embodiment. [Figure 8] This is a side view showing the dashboard of the electric roller according to the first embodiment. [Figure 9] This is a side view showing the brake pedal when the electric roller is moving forward, according to the first embodiment. [Figure 10] This is a side view showing the electric roller according to the first embodiment, when the brake pedal is pressed. [Figure 11] This is a partially transparent side view of an electric roller according to the first embodiment. [Figure 12] This is a partially transparent plan view of an electric roller according to the first embodiment. [Figure 13] This is a cross-sectional view showing the front wheel of an electric roller according to the first embodiment. [Figure 14] This is a plan view showing the first gearbox of an electric roller according to the first embodiment. [Figure 15] This is a cross-sectional view taken along line XV-XV in Figure 14. [Figure 16]It is a cross-sectional view taken along line XVI-XVI of FIG. 14. [Figure 17] It is a cross-sectional view showing the rear wheel of the electric roller according to the first embodiment. [Figure 18] It is a cross-sectional view taken along line XVIII-XVIII of FIG. 17. [Figure 19] It is a side view showing the steering system of the electric roller according to the first embodiment. [Figure 20] It is a plan view showing the steering system of the electric roller according to the first embodiment. [Figure 21] It is a graph showing the relationship between time and rotational speed in the comparative example at startup. [Figure 22] It is a graph showing the relationship between time and rotational speed in the comparative example at shutdown. [Figure 23] It is a graph showing the drive command values of the electric motors for the pressure rollers in the comparative example and the examples in relation to time and rotational speed. [Figure 24] It is a graph showing the relationship between time and rotational speed in the examples at startup. [Figure 25] It is a graph showing the relationship between time and rotational speed in the examples at shutdown. [Figure 26] It is a graph showing the drive command values of the electric motors for the pressure rollers in the modified example in relation to time and rotational speed.

BEST MODE FOR CARRYING OUT THE INVENTION

[0012] [First Embodiment] The electric roller of the present invention will be described in detail with reference to the drawings. The embodiments, modified examples, etc. described below are merely illustrative, and the respective embodiments and modified examples can be used in appropriate combinations. The up-down, left-right, and front-back directions shown in the drawings follow the traveling direction of the electric roller.

[0013] [Overall Schematic Configuration] As shown in Figures 1-4, the electric roller 1 mainly consists of a front wheel R1, a rear wheel R2, a vehicle frame 2, electric motors M (M1-M4), inverters J (J1-J4), batteries K (K1-K3), and a control unit 3.

[0014] The front wheel R1 is rotatably supported by a pair of front wheel side plates SP1 and SP2 provided on the front of the vehicle frame 2. The front wheel R1 is a compaction wheel that compacts the road surface, and in this embodiment it is composed of a single iron wheel. The front wheel R1 may be composed of multiple tires or multiple iron wheels.

[0015] The rear wheel R2 is rotatably supported at the rear of the vehicle frame 2. The rear wheel R2 is a compaction wheel that compacts the road surface, and in this embodiment, it consists of four tires (R2A, R2B, R2C, R2D). The rear wheel R2 may consist of one or more iron wheels.

[0016] The vehicle frame 2 is a vehicle body that rotatably supports the front wheels R1 and R2. The vehicle frame 2 comprises a front frame 11, a rear frame 12, a driver's seat 13, and a dashboard 14. The front frame 11 has front wheel side plates SP1 and SP2 fixed to its front. Inside the front frame 11 is a front space 15 that houses the inverter J and battery K. The rear frame 12 comprises the driver's seat 13 and dashboard 14, and also has a rear space 16 that houses the electric motor M, inverter J1, gearbox, etc. The rear space 16 comprises a first rear space 16a formed below the footwell 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 articulated pins parallel to the vertical direction. The electric roller 1 in this embodiment is articulated, but it may also be rigid.

[0017] 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 according to the 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 according to the drive command value input from the control unit 3 to the right rear wheel inverter J2.

[0018] 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 according to the drive command value input from the control unit 3 to the left rear wheel inverter J3. The electric motors M1 for the front wheels, M2 for the right rear wheel, and M3 for the left rear wheel are collectively referred to as "electric motors for the compaction wheels." Furthermore, the inverter J1 for the front wheels, the inverter J2 for the right rear wheel, and the inverter J3 for the left rear wheel are collectively referred to as "inverters for compaction wheels."

[0019] As shown in Figure 4, the vibration motor M4 is an electric motor that drives the excitation shaft 130. The vibration motor M4 is driven according to the drive command value input from the control unit 3 to the vibration inverter J4.

[0020] As shown in Figure 6, the battery K is a component that supplies power to various components such as the electric motor M and the inverter J. In this embodiment, the battery K comprises a 48V battery K1, a 24V battery K2, and a 12V battery K3, and is housed in a battery case KA (see Figure 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 for the battery K, but any number of types may be used, or it 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 each component. 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 can cooperate with each other via CAN communication for transmitting battery information.

[0021] As shown in Figure 5, the electric roller 1 operates by outputting drive command values ​​from the control unit 3 to the inverters J (J1 to J3) according to the tilt angle of the forward / reverse lever 17 controlled by the operator OP. The electric motors M (M1 to M3) rotate according to the drive command values ​​input to each inverter J, causing the vehicle to move forward or backward. Conventionally, a hydraulic pump was operated using an internal combustion engine (engine, etc.) that burned fuel such as gasoline to drive the compaction wheels, whereas the electric roller 1 of this embodiment differs in that it does not have an internal combustion engine and the power source for the compaction wheels is only the battery K. Furthermore, conventionally, the acceleration and deceleration of the vehicle's travel speed was adjusted by hydraulic control, whereas the electric roller 1 of this embodiment differs in that it is controlled by drive command values ​​output from the control unit 3 to the inverters J.

[0022] <Driving System> Next, the driving 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 equipped with a brake pedal BP that protrudes to the rear, and a display 18 is located on its top surface. The steering wheel 19 is a device that determines the direction of travel of the vehicle and is located on the top surface of the dashboard 14. The steering wheel 19 is connected to an orbit roll (registered trademark, hereinafter the same; see Figures 4 and 19) 51 located inside the dashboard 14.

[0023] As shown in Figure 1, the brake pedal BP is located at the lower rear of the dashboard 14 and is configured to activate the brake when pressed by the operator OP. The forward and reverse levers 17, 17 are located on both sides of the dashboard 14 and are tiltable to a neutral position, a forward position, and a reverse position. The forward and reverse levers 17 may be located on only one side of the dashboard 14.

[0024] As shown in Figure 7, the forward and reverse levers 17, 17 are connected to both ends of the shaft 21. The shaft 21 is located inside the dashboard 14 along the width direction of the vehicle. As shown in Figure 8, the shaft 21 is provided with a plate-shaped base plate 22 that rotates synchronously with the shaft 21 and is fixed perpendicular to the shaft 21.

[0025] As shown in Figure 9, the brake pedal BP is configured to move in conjunction with the shaft 21. The base plate 22 has a first pin 22a and a second pin 22b that protrude in the width direction of the vehicle. The first pin 22a and the second pin 22b are positioned at approximately equidistant distances from the shaft 21. The brake pedal BP comprises a main plate 23, a pedal portion 24, a pivot point portion 25, and a connecting pivot point portion 26.

[0026] The main plate 23 is a plate-shaped member with a pedal portion 24 at its rear. The front end of the main plate 23 is rotatably fixed via a bracket 27 that is fixed to the front wall of the dashboard 14. The pivot point 25 is the pivot center of the brake pedal BP. The connecting pivot point 26 is formed on the upper part of the main plate 23.

[0027] The connecting pivot point 26 is connected to the base plate 22 via the first brake pedal rod 28 and the 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 pivot point 26 by pin connections.

[0028] An elongated hole 28a is formed at the upper end of the first brake pedal rod 28, into which the first pin 22a is loosely fitted. An elongated hole 29a is formed at the upper end of the second brake pedal rod 29, into which the second pin 22b is loosely fitted. When viewed from the side, the first brake pedal rod 28 and the second brake pedal rod 29 have a V-shape.

[0029] In the initial position (with the forward / reverse lever 17 in the neutral position), the base plate 22 is approximately horizontal. Also, the first pin 22a and the second pin 22b are located slightly above the center in the height direction within the elongated holes 28a and 29a.

[0030] Figure 9 is a diagram showing the operation around the base plate 22 when the forward / reverse lever 17 is tilted to its maximum forward position. As shown in Figure 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 located at the upper end of the elongated hole 28a of the first brake pedal rod 28. On the other hand, the second pin 22b is located slightly below the middle of the elongated hole 29a of the second brake pedal rod 29 in the height direction. Even when the forward / reverse lever 17 is tilted forward, the position of the brake pedal BP does not change because the first pin 22a and the second pin 22b move within the elongated holes 28a and 29a, respectively.

[0031] Although a detailed illustration is omitted, when the forward / reverse lever 17 is tilted backward to move the vehicle in reverse, the base plate 22 rotates clockwise in sync with the shaft 21. In this case as well, even when the forward / reverse lever 17 is tilted backward, the first pin 22a and the second pin 22b move within the elongated holes 28a and 29a, respectively, so the position of the brake pedal BP does not change.

[0032] Figure 10 is a diagram showing the operation around the base plate 22 when the brake pedal BP is pressed. As shown in Figure 10, when the operator OP presses the brake pedal BP, the brake pedal BP rotates downward around the pivot point 25. Consequently, 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 at a predetermined angle and becomes approximately horizontal. Synchronized with these movements, the shaft 21 and the forward / reverse lever 17 also rotate to the neutral position, so the brakes are activated and braking occurs.

[0033] As explained above, the operator OP can return the forward / reverse lever 17 to the neutral position or depress the brake pedal BP, thereby bringing the forward / reverse lever 17 to the neutral position and braking the vehicle. Details of the braking system will be described later.

[0034] As shown in Figures 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. The shaft 21 is provided with a connecting plate 34 that extends in a direction perpendicular to the axial direction. The potentiometer 31 is also provided with a connecting plate 35 that is connected to the potentiometer 31 and rotates in sync with the connecting plate 34. A connecting rod 33 is also provided that connects the connecting plates 34 and 35 to each other. When the forward / reverse lever 17 is tilted, the tilt angle can be detected by the potentiometer 31 through the link mechanism composed of the connecting plates 34 and 35 and the connecting rod 33. The detection result from the potentiometer 31 is output to the control unit 3.

[0035] Furthermore, as shown in Figure 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.

[0036] Furthermore, the display 18 located on the top surface of the dashboard 14 displays various vehicle information held by the control unit 3, such as the speedometer, battery K level, mileage, hour meter, and alert information. The display 18 may also display a touch-sensitive operation panel. In addition, the display 18 may also display information related to compaction, such as the compaction status of the construction site, map information of the compaction area, and location information.

[0037] Furthermore, as shown in Figures 4 and 6, the top surface of the dashboard 14 is equipped with a drive H / L switch 36, a parking button 37, a vibration button 39, a lighting button 40, an alarm button 41, and the like.

[0038] The H / L driving switch 36 is a switch that allows you to select between high-speed driving mode and low-speed driving mode. When the forward / reverse lever 17 is tilted to its maximum position (full throttle), for example, the high-speed driving mode is set to 10 km / h and the low-speed driving mode is set to 5 km / h. These speeds can be set as appropriate.

[0039] The parking button 37 is a button that allows the user to select whether to activate or release the parking brake. The vibration button 39 is a button that allows the user to select whether to turn the front wheel R1 vibration ON or OFF. A button that controls the intensity (rotation speed) of the vibration in conjunction with the vibration button 39 may also be provided. The lighting button 40 is a button that allows the user to select whether to turn ON or OFF the hazard lights that flash when the vehicle is stopped, for example. The alarm button 41 is a button that allows the user to select whether to turn ON or OFF the backup buzzer when reversing, for example. The ON or OFF status of these function switches (buttons) may be displayed on the display 18.

[0040] As shown in Figure 4, the inverter J comprises an inverter J1 for the front wheels, an inverter J2 for the right rear wheel, an inverter J3 for the left rear wheel, and a vibration inverter J4. The inverter J is a device that controls the frequency based on the drive command value output from the control unit 3 and changes the rotational speed of each electric motor M.

[0041] As shown in Figure 4, the electric motor M comprises an electric motor M1 for the front wheels, an electric motor M2 for the right rear wheel, an electric motor M3 for the left rear wheel, and an electric motor M4 for vibration. The type of electric motor M can be selected as appropriate, but in this embodiment, induction motors are used for all of them.

[0042] <Structure of the front wheel R1 (vibration system)> As shown in Figure 13, the front wheel R1 is equipped with a roll 111, and an electric motor M1 for the front wheel and an electric motor M4 for vibration are installed at both ends in the width direction of the vehicle. The roll 111 has a hollow cylindrical shape, and a first end plate 112 and a second end plate 113 are provided on its inner surface at a distance from each other. A hollow cylindrical vibrator case 114 is fixed between the first end plate 112 and the second end plate 113. The inside of the vibrator case 114 is filled with lubricating oil. A first holder 115 is attached to the first end plate 112, and a second holder 116 is attached to the second end plate 113. The first holder 115 is supported by a cylindrical housing 118 via a bearing 117. The housing 118 hangs down from the left side of the vehicle frame 2, and its lower end is attached to the side plate SP1 located inside the roll 111 via vibration-damping rubber 121 and support member 122.

[0043] The second holder 116 is fixed to the second end plate 113. The front wheel electric motor M1 is attached to the side plate SP2, which hangs down from the right side of the vehicle frame 2 and whose lower end is located around the roll 111, via a motor mounting plate 124. A reduction gear mechanism 125 is installed on the output section M1a of the front wheel electric motor M1. The output section M1a is connected to the second end plate 113 via vibration-damping rubber 123 and support member 126. A cover 127 is attached to the right end of the second holder 116.

[0044] As described above, when the front wheel electric motor M1 rotates, its rotational force is reduced by the reduction gear mechanism 125 and transmitted to the disc 126 and the second end plate 113, and the roll 111 rotates while the first holder 115 is supported by the housing 118.

[0045] Meanwhile, the vibration motor M4 is mounted via a motor mounting plate 128 connected to the side plate SP1. A joint member (e.g., a constant velocity joint) 129 connects the output shaft of the vibration motor M4 to the excitation shaft 130.

[0046] The vibration generating shaft 130 extends in the vehicle width direction within the vibration generating machine case 114, with an axis coaxial with the roll 111. The vibration generating shaft 130 comprises a main body portion 131, support shaft portions 132 and 133 provided at both ends of the main body portion 131, and an eccentric weight 134. The main body portion 131 is an axial portion, with support shaft portions 132 and 133, which have a smaller diameter than the main body portion 131, provided at both ends. Support shaft portion 132 is supported by the first holder 115 via a bearing 135. Support shaft portion 133 is supported by the second holder 116 via a bearing 136. An eccentric weight 134 is provided on the outer circumferential surface of the main body portion 131.

[0047] As described above, when the vibration motor M4 rotates, its rotational force is transmitted to the vibration shaft 130 via the joint member 129, causing the vibration shaft 130 to rotate relative to the first holder 115 and the second holder 116. At that time, the roll 111 vibrates because the vibration shaft 130 is equipped with an eccentric weight 134.

[0048] When operator OP operates the vibration button 39 (see Figure 4), a vibration signal is output from the control unit 3 to the vibration inverter J4, and the vibration motor M4 operates based on the drive command value of the vibration inverter J4. Alternatively, additional operation buttons may be provided, for example, to provide a high vibration mode or a low vibration mode. Rotating the vibration motor M4 at high speed increases the vibration, while rotating it at low speed decreases the vibration. Furthermore, the rotation speed of the vibration motor M4 may be freely controlled according to the operator OP's operation, allowing for adjustment of the vibration intensity.

[0049] In this embodiment, the vibration excitation shaft 130 (vibration system) is provided only on the front wheel R1, but it may also be provided on the rear wheel R2, or it may be provided only on the rear wheel R2.

[0050] <Deceleration mechanism> As shown in Figures 14-18, the rotational force of the right rear wheel electric motor M2 and the left rear wheel electric motor M3 is transmitted to the rear wheel R2 via a reduction mechanism. The reduction mechanism consists of a first gearbox 200A and a second gearbox 200B and is provided from the second rear space 16b of the rear space 16 to the rear wheel R2. As shown in Figure 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.

[0051] The first gearbox 200A comprises a first gear 201, a second gear 204, a third gear 205, and a fourth gear 207. The first gearbox 200A is a box-shaped body exhibiting a rectangular parallelepiped and is located inside the second rear space 16b. The first gear 201, second gear 204, third gear 205, and fourth gear 207 all have their rotation axes arranged parallel to the vehicle width direction. The inside of the first gearbox 200A is filled with lubricating oil.

[0052] The first gear 201 comprises a shaft portion 201a and a gear portion 201b provided on the shaft portion 201a. The shaft portion 201a is connected at both ends to the output shafts of the right rear wheel electric motor M2 and the left rear wheel electric motor M3, respectively, and is supported by bearings 202, 202 provided on the first gearbox 200A.

[0053] The second gear 204 comprises a shaft portion 204a and a large-diameter gear 204b and a small-diameter gear 204c provided on the shaft portion 204a. The shaft portion 204a is supported at both ends by bearings 203, 203 provided on the first gearbox 200A. The large-diameter gear 204b meshes 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 meshes with the gear portion 207b of the fourth gear 207.

[0054] The third gear 205 comprises 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 on the first gearbox 200A. A non-excitation brake (negative brake) 62 is connected to the tip of the shaft portion 205a. In other words, the non-excitation brake 62 is connected to the outside of the first gearbox 200A via the shaft portion 205a.

[0055] The fourth gear 207 comprises 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 connects the first gearbox 200A and the second gearbox 200B and is supported by bearings 209, 209 provided on the second gearbox 200B. A sealing member 208 is interposed between the first gearbox 200A and the outer circumference of the shaft portion 207a. The large-diameter gear 207b is located inside the first gearbox 200A and meshes with the small-diameter gear 204c of the second gear 204. The small-diameter gear 207c is located inside the second gearbox 200B.

[0056] As shown in Figure 17, the second gearbox 200B is positioned alongside the first gearbox 200A and is a vertically elongated box-shaped body located from the second rear space 16b to the rear wheel R2. The fifth gear 210 comprises 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 gearbox 200B. The gear portion 210b meshes with the small-diameter gear 207c of the fourth gear 207 and the gear portion 213b of the sixth gear 213, respectively.

[0057] The sixth gear 213 comprises a shaft portion 213a and a gear portion 213b provided on the shaft portion 213a. The shaft portion 213a is a shaft that extends from the rear wheel R2 to the tires R2A to R2D. Holders 218A and 218B extend from the lower part of the second gearbox 200B, extending to the left and right in the vehicle width direction and supporting the shaft portion 213a via bearings 214. The left end of the shaft portion 213a is fastened to the hub 216A via a fastening portion 217A. The hub 216A also supports the disc wheels DWA and DWB, which are located inside the tires R2A and R2B.

[0058] Similarly, the right end of the shaft portion 213a is fastened to the hub 216B via the fastening portion 217B. The hub 216B also supports the disc wheels DWC and DWD, which are located inside the tires R2C and R2D.

[0059] In the reduction mechanism configured as described above, the rotational force of the electric motor M2 for the right rear wheel and the electric motor M3 for the left rear wheel is 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 is also transmitted to the rear wheel R2 via the hubs 216A and 216B.

[0060] <Steering System> Next, the steering system will be described. As shown in Figure 19, the steering system comprises 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 are connected by piping to form a hydraulic circuit.

[0061] 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 part of the piping and is a component that removes impurities such as dust and iron contained in the hydraulic fluid. The accumulator 54 is connected to a part of the piping and is a device that stores and releases the fluid energy of the hydraulic fluid. The filter 53 and the accumulator 54 are located in the second rear space 16b. As shown in Figure 20, the hydraulic cylinders 55, 55 are cylinders that connect the front frame 11 and the rear frame 12 and are arranged in pairs on both sides in the vehicle width direction. The extension and retraction of the hydraulic cylinders 55, 55 allows the vehicle to turn left and right.

[0062] As shown in Figure 4, the pressure switch 56 checks the pressure in the hydraulic circuit and determines whether to start or stop the electric hydraulic pump 52. The control unit 3 receives a detection signal from the pressure switch 56 and starts the electric hydraulic pump 52 if the pressure in the hydraulic circuit falls below a predetermined value, and stops the electric hydraulic pump 52 if it is above the predetermined value. The pressure switch 56 can also detect pressure errors in the hydraulic circuit.

[0063] The steering system includes an electric hydraulic pump 52, hydraulic cylinders 55, 55 driven by pressurized oil discharged from the electric hydraulic pump 52, and a steering valve (not shown) that controls the direction and flow rate of pressurized oil supplied from the electric hydraulic pump 52 to the hydraulic cylinders 55, 55. The steering valve is switched according to the rotation direction and amount of the steering 19 to drive and control the hydraulic cylinders 55, 55. The switching of the steering valve according to the rotation direction and amount of the steering 19 is performed by an orbit roll 51.

[0064] <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 The neutral brake, as shown in Figure 4, is a brake that operates when the forward / reverse lever 17 is moved to the neutral position by the operator OP. During stopping, the vehicle decelerates by applying regenerative motion and reverse braking of the electric motor for the compaction wheels, and is electrically stopped by the zero-speed holding brake (excitation brake 61). The excitation brake 61 is a brake that operates when energized and is released when de-energized.

[0065] 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 rear right wheel inverter J2, and the rear left wheel inverter J3 so that the front wheel electric motor M1, the rear right wheel electric motor M2, and the rear left wheel electric motor M3 each rotate at 0 revolutions. The control unit 3 also outputs a brake signal to the excitation brake 61. After a predetermined time has elapsed since outputting the drive command value (holding at 0 revolutions) to each inverter J, the control unit 3 activates the de-excitation brake 62 (Figures 4 and 14) via an operating relay and releases the brake of the excitation brake 61. This predetermined time can be set as appropriate. The de-excitation brake 62 is controlled by an operating relay connected to the control unit 3.

[0066] (2) Foot brake (emergency stop) As shown in Figures 4 and 8, the foot brake is activated by pressing the brake pedal BP. When the operator OP presses 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. Also, when the brake pedal BP is pressed, the base plate 22, which was tilted as described above by the mechanism in Figures 9 and 10, returns to the horizontal position. In other words, the shaft 21 (forward / reverse lever 17) is in the neutral position, and the neutral brake is activated.

[0067] (3) Parking brake As shown in Figure 4, the parking brake is activated by pressing the parking button 37. When the operator OP presses the parking button 37, a parking brake signal is output to the control unit 3. The control unit 3 then activates the de-excitation brake 62.

[0068] As shown in Figure 16, the de-excitation brake 62 is a mechanical disc brake that operates when the vehicle is not energized. The de-excitation brake 62 is electrically connected to a 24V battery K2. When energized, the rotor 64 of the de-excitation brake 62 rotates in sync with the shaft 205a of the third gear 205. This allows the third gear 205 to rotate, enabling the vehicle to move. On the other hand, when the vehicle is not energized, the rotor 64 is clamped, preventing the rotation of the shaft 205a, and the brake operates. The de-excitation brake 62 is provided with a release lever 63. The operator OP or worker can release the de-excitation brake 62 by operating the release lever 63.

[0069] <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. The 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 the measured data, a balancing function to keep the voltage between each cell constant, and a function to detect overcharging and over-discharging. The Battery Management Unit 71 and the control unit 3 can communicate battery information via CAN communication.

[0070] The 12V battery K3 is a lead-acid battery. The 12V battery K3 is electrically connected to the 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., backup buzzer, alert buzzer) 41. The 12V battery K3 can supply power to the electric roller 1 for starting (restarting) and to various electrical components even when the control unit 3 goes down, for example.

[0071] 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 steps down 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 de-excitation brake 62.

[0072] The control unit (VCU) 3 is a device that determines the state of the vehicle as it changes during operation and controls each component to maintain the optimal state. The control unit 3 controls each component that interacts with each other, such as the electric motor M, inverter J, and battery K, while taking into account their effects on other components.

[0073] The control unit 3 includes a arithmetic unit (CPU: Central Processing Unit), a memory unit, a communication unit, etc. The control unit 3 can be located anywhere, but in this embodiment it is attached to the front of the battery case KA (see Figure 11) of the battery K. The arithmetic unit is the part that reads the program stored in the memory unit and makes it function as a functional unit. The memory unit includes RAM (Random Access Memory), ROM (Read-only memory), HDD (Hard Disk Drive), etc. Various programs and drive instruction values ​​for each inverter J in relation to the tilt angle of the potentiometer 31 are stored in the memory unit as drive instruction value files. The communication unit is, for example, CAN communication and is able to communicate with each component.

[0074] Furthermore, the control unit 3 may be linked with a GNSS (Global Navigation Satellite System) to acquire and utilize driving records, location information, driving conditions, etc. The control unit 3 may also be linked with a compaction management device equipped with sensors to acquire road surface compaction information to acquire and utilize compaction information in real time. The control unit 3 may also be linked with an autonomous driving device to enable remotely controlled autonomous driving. Additionally, the control unit 3 can transmit vehicle operation information (driving time, abnormal information, battery status, etc.) to a technical center, leasing company, etc., and store and manage this information.

[0075] <About the effects and mechanisms> When the operator OP tilts the forward / reverse lever 17 forward, the machine moves forward; when tilted backward, it 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 rear right wheel inverter J2, and the rear left wheel inverter J3, and operates the electric motors for the compaction wheels based on these drive command values. Increasing the tilt angle of the forward / reverse lever 17 results in faster movement, while decreasing it results in slower movement. When the forward / reverse lever 17 is returned to the neutral position, the neutral brake described above is activated, and the electric roller 1 stops.

[0076] When operator OP operates the vibration button 39, a vibration signal is output to the control unit 3. The control unit 3 transmits a vibration command value to the vibration inverter J4 and operates the vibration electric motor M4 based on the vibration command value. As a result, the excitation shaft 130 rotates and the front wheel R1 vibrates.

[0077] As described above, the electric roller 1 according to this embodiment can substantially eliminate fuel consumption and greenhouse gas emissions through electrification. Furthermore, since electrification can reduce noise and substantially eliminate greenhouse gas emissions, it can reduce the burden on the operator OP and improve the working environment. In addition, since it does not use a hydraulic pump or hydraulic circuit for travel as in the conventional model, it does not require the replacement of hydraulic fluid, etc., resulting in excellent maintainability.

[0078] Furthermore, according to this embodiment, multiple electric motors for the compaction wheels (electric motor M1 for the front wheels, electric motor M2 for the right rear wheel, and electric motor M3 for the left rear wheel) are provided. While one electric motor for the compaction wheels is sufficient, providing multiple motors allows for increased main torque while preventing the motors from becoming too large. This enables stopping and starting on inclines.

[0079] Furthermore, according to this embodiment, since a potentiometer 31 is provided, fine speed control is possible according to the tilt of the forward / reverse lever 17. In addition, since a limit switch 32 is provided, the neutral position can be reliably detected. Although neutral position can be detected with the potentiometer 31 alone, if an error occurs in the input from the potentiometer 31, the vehicle may start moving even if the forward / reverse lever 17 is in the neutral position. However, according to this embodiment, since a limit switch 32 is provided, the neutral position can be reliably detected.

[0080] Furthermore, according to this embodiment, the vehicle is equipped with electrical components including a lighter 40 and an alarm 41, and is equipped with multiple batteries K with different voltages, each electrically connected to the electric motor for the compaction wheel and the electrical components. This allows power to be supplied according to the voltage of each component. In addition, since the 48V battery K1 and the 24V battery K2 are lithium-ion batteries (storage batteries), they can be recharged and reused repeatedly.

[0081] Furthermore, according to this embodiment, since the battery K is installed in the front space 15 of the vehicle frame 2, miniaturization can be achieved by effectively utilizing the space. In other words, the battery K can be placed in the area where the engine was previously installed. In addition, the battery K can be protected by housing it in a battery case KA. The battery K may be installed only in the rear space 16, or it may be installed in both the front space 15 and the rear space 16.

[0082] Furthermore, according to this embodiment, the electrical components, including the lighter 40 and alarm 41, are electrically connected to a 12V battery K3 consisting of a lead-acid battery. This configuration ensures that the electrical components, including the lighter 40, continue to function even when the control unit 3 goes down. Therefore, even if the system goes down, alerts can be issued to the surrounding area, and restarting and rebooting can be performed smoothly.

[0083] Furthermore, according to this embodiment, the speed meter 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. As a result, the operator OP can understand 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.

[0084] Furthermore, while a mechanism for vibrating the compaction wheels may be provided as needed, in this embodiment, the vibration shaft 130 is operated by a vibration inverter J4 and a vibration electric motor M4. This makes it easy to control the vibration of the vibration shaft 130, and by electrifying the vibration shaft 130, fuel consumption and greenhouse gas emissions can be substantially eliminated. In addition, since noise can be reduced and greenhouse gas emissions can be substantially eliminated by electrifying the vibration shaft 130, the burden on the operator OP can be reduced and the working environment can be improved. Moreover, since a hydraulic pump and hydraulic circuit for vibration are not used as in the conventional method, the replacement of hydraulic fluid is unnecessary, resulting in excellent maintainability.

[0085] Furthermore, according to this embodiment, by installing the vibration electric motor M4 on a spring (above the vibration-damping rubber 121 (on the vehicle frame 2 side)), the vibrations acting on the vibration electric motor M4 can be reduced. In addition, by providing a constant velocity joint that connects the excitation shaft 130 and the output shaft of the vibration electric motor M4, the drive of the vibration electric motor M4 can be transmitted to the excitation shaft 130 even when an operating angle is applied.

[0086] Furthermore, according to this embodiment, since an electric hydraulic pump 52 is used in the steering system, fuel consumption and greenhouse gas emissions can be substantially eliminated by electrification. In addition, since noise can be reduced and greenhouse gases can be substantially eliminated by electrification, the burden on the operator OP can be reduced and the working environment can be improved. Moreover, according to this embodiment, since the hydraulic cylinder 55 is driven by the electric hydraulic pump 52, changes to the steering mechanism can be kept to a minimum when electrifying.

[0087] Furthermore, according to this embodiment, since pressure can be accumulated in the accumulator 54, it is possible to prevent the electric hydraulic pump 52 from burning out due to continuous operation and to suppress energy consumption.

[0088] Furthermore, according to this embodiment, since the electric hydraulic pump 52, piping, and accumulator 54 are installed in the rear space 16 of the vehicle frame 2, the rear space 16 can be used effectively, and the number of pipes and the like that need to be spanned between the front space 15 and the rear space 16 can be reduced.

[0089] Furthermore, according to this embodiment, since the hydraulic cylinders 55 are installed on both the left and right sides of the vehicle frame 2, the difference in the amount of oil discharged in the left and right directions during turning can be reduced or eliminated, thereby stabilizing the vehicle's behavior during turning. Note that the number of hydraulic cylinders 55 may be just one per the vehicle frame 2. This simplifies the structure and reduces the number of parts.

[0090] Furthermore, according to this embodiment, when the forward / reverse lever 17 is in the neutral position, the control unit 3 outputs a 0 rotation signal to the compaction wheel inverters (front wheel inverter J1, rear right wheel inverter J2, rear left wheel inverter J3) and activates the excitation brake 61. This allows for easy configuration of the brake system, and the electrification of the brake system effectively eliminates fuel consumption and greenhouse gas emissions. In addition, electrification reduces noise and effectively eliminates greenhouse gases, thereby reducing the burden on the operator OP and improving the working environment. Moreover, since the brake system does not use a hydraulic circuit as in conventional systems, maintenance is excellent as there is no need to change the hydraulic fluid, etc.

[0091] Furthermore, according to this embodiment, the control unit 3 activates a de-excitation brake 62, which mechanically applies braking, after a predetermined time has elapsed since the excitation brake 61 was activated. When the excitation brake 61 is activated, power is continuously consumed while the vehicle is stopped. However, according to this embodiment, after a predetermined time has elapsed, the system switches to the de-excitation brake 62, and the braking of the excitation brake 61 is released, thus reducing power consumption.

[0092] Furthermore, when the operator OP presses the brake pedal BP, or operates a button (parking button 37) located on the dashboard 14 or the driver's seat 13, the control unit 3 activates a de-excitation brake 62 that mechanically applies braking via an operating relay. This allows the vehicle to be stopped in an emergency.

[0093] Furthermore, by providing a release lever 63 around the driver's seat 13 for releasing the de-excitation brake 62, the operation of releasing the de-excitation brake 62 can be easily performed.

[0094] [Second Embodiment: Over-rotation prevention mechanism for electric motor for compaction wheel] 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 to prevent over-rotation of the front wheel electric motor M1, the rear right wheel electric motor M2, and the rear left wheel electric motor M3 (electric motor for compaction wheel). The second embodiment will be described mainly in terms of the differences from the first embodiment. Note that the drive command values ​​and times shown below are merely examples, and these values ​​can be set as appropriate.

[0095] <Challenges> As described above, the electric roller 1 receives input from the control unit 3 based on the tilt of the forward / reverse lever 17, and the control unit 3 outputs a drive command value for acceleration, deceleration, or stopping to each inverter J. Each inverter J that receives the drive command value from the control unit 3 controls the vehicle's movement by outputting a drive command value for rotational speed to the electric motor for the compaction wheel in order to accelerate or decelerate according to the input amount of the forward / reverse lever 17.

[0096] However, the above-described embodiment has the problem that the vehicle behavior during acceleration, deceleration, or stopping is unstable. For example, when accelerating, if the forward / reverse lever 17 is operated to full throttle in the forward direction, the drive command value input to the inverter J rises rapidly from 0 revolutions to the target drive command value. At this time, because the output of the electric motor for the compaction wheels is small, it is not possible to suppress the inertial force generated during acceleration. As a result, the rotational speed of the electric motor for the compaction wheels becomes excessive relative to the target drive command value due to the uncontrollable inertia.

[0097] On the other hand, during deceleration and stopping, deceleration is achieved by applying regenerative motion and reverse braking as control of the electric motor for the compaction wheels. When the forward / reverse lever 17 is returned from the full throttle position to the neutral position during deceleration and stopping, the drive command value output to the electric motor for the compaction wheels drops sharply to 0 revolutions. At this time, the braking torque generated cannot be controlled due to insufficient output from the electric motor for the compaction wheels, resulting in a rebound motion due to the uncontrollable braking torque when stopping.

[0098] These issues will be explained in more detail. Figure 21 is a graph showing the relationship between time and rotational speed for a comparative example during startup. As shown in Figure 21, the thin line indicates the input of the forward / reverse lever 17. The forward / reverse lever 17 is, for example, in the most tilted position in the forward or reverse direction (full throttle state).

[0099] The dotted line indicates the drive command value for the compaction wheel electric motor in the comparative example. In other words, it is the drive command value output from the control unit 3 to the compaction wheel inverter. In the comparative example shown in Figure 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-side command start point W1," the point at which the drive command value of the compaction wheel electric motor reaches the target drive command value P1 (the point reached in calculations) is defined as the "acceleration-side target rotational speed arrival point N1," and the line connecting the acceleration-side command start point W1 and the acceleration-side target rotational speed arrival point N1 is defined as the "first stage acceleration Q1." In the comparative example, for example, the setting is to reach 2200 rpm from 0 rpm in approximately 3.0 seconds.

[0100] The thick line indicates the rotational speed (actual rotational speed) of the compaction wheel electric motor in the comparative example. Immediately after the acceleration instruction start point W1, the rotational speed of the compaction wheel electric motor in the comparative example is lower than the first-stage acceleration Q1, which is the drive instruction value. On the other hand, after reaching the acceleration target rotational speed point N1, the rotational speed of the compaction wheel electric motor exceeds the target drive instruction value P1 for a predetermined time because the inertial force generated during acceleration cannot be suppressed. Furthermore, after falling slightly below the target drive instruction value P1, the rotational speed of the compaction wheel electric motor and the target drive instruction value P1 become equal. In other words, in this comparative example, after reaching the acceleration target rotational speed point N1, the compaction wheel electric motor enters an over-rotation state for a predetermined time, resulting in unstable vehicle behavior.

[0101] Figure 22 is a graph showing the relationship between time and rotational speed in the comparative example when stopped. As shown in Figure 22, when stopped, the target drive instruction 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 side instruction start point W2," the point at which the drive instruction value of the electric motor for the compaction wheel reaches the target drive instruction value P2 (the point reached in calculations) is defined as the "deceleration side target rotational speed arrival point N2," and the straight line connecting the deceleration side instruction start point W2 and the deceleration side target rotational speed arrival point N2 is defined as the "first stage deceleration Q2." In the comparative example, for example, the setting is such that it goes from 2200 rpm to 0 rpm in about 2.0 seconds.

[0102] In the comparative example, the rotational speed of the compaction wheel electric motor is higher than the drive command value immediately after the deceleration instruction start point W2. On the other hand, after reaching the deceleration target rotational speed point N2, the generated braking torque cannot be controlled due to insufficient output from the compaction wheel electric motor, so the rotational speed of the compaction wheel electric motor falls below the target drive command value P2 for a predetermined time. After that, the rotational speed of the compaction wheel electric motor and the target drive command value P2 become equal. In other words, in this comparative example, after reaching the deceleration target rotational speed point N2, the compaction wheel electric motor becomes over-rotating for a predetermined time, resulting in unstable vehicle behavior (rebound motion when stopped).

[0103] <Configuration of the over-speed prevention mechanism for the electric motor used for compaction wheels - starting side> Figure 23 is a graph showing the relationship between time and rotational speed for the drive command values ​​of the compaction wheel electric motors in the comparative example and the embodiment. The solid line shows the drive command values ​​of the compaction wheel electric motor in the embodiment. The dotted line shows the drive command values ​​of the compaction wheel electric motor in the comparative example.

[0104] As shown by the solid line in Figure 23, at startup in the embodiment, the drive command value of the electric motor for the compaction wheel includes an acceleration-side shift point U1, as well as a first-stage acceleration Q3 and a second-stage acceleration Q4. The slope (acceleration) of the first-stage acceleration Q3 is greater (steeper angle) than the slope (acceleration) of the first-stage acceleration Q1 in the comparative example. On the other hand, the slope of the second-stage acceleration Q4 is smaller (gentler angle) than the slope of the first-stage acceleration Q1 in the comparative example.

[0105] Figure 24 is a graph showing the relationship between time and rotational speed in the embodiment during startup. In Figure 24, the dotted line shows the drive command value of the electric motor for the compaction wheel in the embodiment. The solid line shows the rotational speed of the electric motor for the compaction wheel in the embodiment. In the embodiment as well, the drive command value of the electric motor for the compaction wheel is set so that the target drive command value P1 is 2200 rpm, and the target drive command value P1 is reached 3.0 seconds from the time of input of the forward / reverse lever 17.

[0106] As shown in Figure 24, in the embodiment, at startup, the slope of the second-stage acceleration Q4 when approaching the target rotational speed point N1 is smaller (gentler angle) than the slope of the first-stage acceleration Q1 in the comparative example. More specifically, in the embodiment, at startup, the slope of the first-stage acceleration Q3 is larger than the slope of the first-stage acceleration Q1 in the comparative example (see Figure 23), so the rotational speed of the electric motor for the compaction wheels increases more rapidly than in the comparative example. Subsequently, the target drive instruction value P1 is reached more gradually with the second-stage acceleration Q4 than in the comparative example. As a result, the target drive instruction value P1 can be reached without the electric motor for the compaction wheels over-rotating (or with reduced over-rotation). Therefore, the vehicle behavior during acceleration can be stabilized.

[0107] <Configuration of the over-speed prevention mechanism for the electric motor used for compaction wheels - stopping side> As shown by the solid line in Figure 23, the stopping side of the embodiment includes a deceleration shift point U2 in the drive command value of the electric motor for the compaction wheel, as well as a first-stage deceleration Q5 and a second-stage deceleration Q6. The slope (deceleration) of the first-stage deceleration Q5 is greater (steeper angle) 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 (gentler angle) than the slope of the first-stage deceleration Q2 of the comparative example.

[0108] Figure 25 is a graph showing the relationship between time and rotational speed in the embodiment when stopped. In Figure 25, the dotted line shows the drive command value of the electric motor for the compaction wheel in the embodiment. The solid line shows the rotational speed of the electric motor for the compaction wheel in the embodiment. In the embodiment, the target drive command value P2 is set to 0 rpm, and the setting is such that the target drive command value P2 is reached 2.0 seconds after the forward / reverse lever 17 returns to the neutral position.

[0109] As shown in Figure 25, when the embodiment stops, the inclination of the second-stage deceleration Q6 as it approaches the target rotational speed point N2 is smaller (gentler angle) than the inclination of the first-stage deceleration Q2 in the comparative example. More specifically, when the embodiment stops, the inclination of the first-stage deceleration Q5 is larger than the inclination of the first-stage deceleration Q2 in the comparative example (see Figure 23), so the rotational speed of the electric motor for the compaction wheels drops more rapidly than in the comparative example. Subsequently, the target drive instruction value P2 is reached gradually with the second-stage deceleration Q6. As a result, the target drive instruction value P2 can be reached without the electric motor for the compaction wheels over-rotating (or with reduced over-rotation). Therefore, rebound during deceleration can be prevented and vehicle behavior can be stabilized.

[0110] Figure 26 is a graph showing the relationship between time and rotational speed for the drive command value of the modified compaction wheel electric motor in terms of the modified example. As shown in Figure 26, the modified example accelerates or decelerates in three stages. As shown by the solid line in Figure 26, the drive command value of the starting-side compaction wheel electric motor in the modified example includes gear 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 rotational speed point N1. The slope of the third-stage acceleration Q13 is smaller (gentler angle) than the first-stage acceleration Q1 of the comparative example. As a result, over-rotation of the compaction wheel electric motor can be prevented, similar to the second embodiment.

[0111] As shown by the solid line in Figure 26, the drive command value of the electric motor for the compaction wheel on the stopping side in the modified example includes gear shift points U5 and U6, as well as a first-stage reduction Q14, a second-stage reduction Q15, and a third-stage reduction Q16. The third-stage reduction Q16 is positioned at the point N2 where the target rotational speed on the reduction side is reached. The slope of the third-stage reduction Q16 is smaller (gentler angle) than that of the first-stage reduction Q2 in the comparative example. This prevents over-rotation of the electric motor for the compaction wheel, just as in the second embodiment. As in the modified example, two or more gear shift points may be provided on the starting side or the stopping side.

[0112] As described above, the over-rotation prevention mechanism for the compaction wheel electric motor has at least one gear shift point in the drive command value of the compaction wheel electric motor, and sets the slope toward the acceleration target rotational speed point N1 and the deceleration target rotational speed point N2 to be smaller than the slope in the comparative example. This allows signals to be output to the compaction wheel inverter in multiple gear shift ranges, enabling the compaction wheel electric motor to reach its target rotational speed gradually.

[0113] In the over-rotation prevention mechanism for the compaction wheel electric motor of this embodiment, when setting the inclination toward the acceleration target rotational speed point N1 and the deceleration target rotational speed point N2 in the drive command value, a reference inclination (here, the inclination of the first-stage acceleration Q1 and first-stage deceleration Q2 in the comparative example) is set from the acceleration target rotational speed point N1 and the deceleration target rotational speed point N2, and the inclination is set to be smaller (the angle becomes gentler) relative to this inclination. The drive command value of the over-rotation prevention mechanism for the compaction wheel electric motor may be set based on a drive command value file that is set in advance according to the tilt angle of the forward / reverse lever 17. The drive command value file is a data file in which the gear shift point is set in advance according to, for example, 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 unit of the control unit 3. Alternatively, the drive command value of the over-rotation prevention mechanism for the compaction wheel electric motor may be calculated by the control unit 3 from the detected tilt angle of the forward / reverse lever 17 and calculated as appropriate.

[0114] [Third Embodiment: Over-rotation prevention mechanism for vibration-type electric motors] 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 equipped with an over-rotation prevention mechanism for the vibration electric motor M4 in the vibration system to prevent over-rotation. The third embodiment will be described focusing on the differences from the first embodiment.

[0115] <Challenges> Similar to the second embodiment, in the vibration electric motor M4, the excitation shaft 130 is equipped with an eccentric weight 134, which may result in over-rotation relative to the target drive command value when starting and stopping vibration. This can lead to unstable vehicle behavior and cause discomfort to the operator OP.

[0116] <Configuration of the over-speed prevention mechanism for a vibration-type electric motor> The over-rotation prevention mechanism for the vibration electric motor includes a gear shift point in the drive command value output from the control unit 3 to the vibration inverter J4. The method for setting the gear shift point is the same as in the second embodiment, so a detailed explanation is omitted. When vibration is started, the control unit 3 outputs signals to the vibration inverter J4 in multiple gear shift ranges, allowing the vibration electric motor J4 to gradually reach its target rotational speed. As a result, the vibration electric motor M4 reaches its target rotational speed gradually, suppressing unstable vibration behavior caused by over-rotation.

[0117] Furthermore, when vibration stops, the control unit 3 outputs signals to the vibration inverter J4 in multiple speed ranges, allowing for a gradual stop. This suppresses the rebound phenomenon of the excitation shaft 130, enabling the excitation shaft 130 to be stopped stably.

[0118] While embodiments of the present invention have been described above, the design can be modified as appropriate, as long as it does not contradict the spirit of the present invention. [Explanation of Symbols]

[0119] 1 Electric roller 2. Vehicle frame 3. Control Unit (VCU) 11 Front frame 12 Rear frame 17 Forward / Forward Lever 18 displays 19 Steering 51 Orbitroll 52 Electric Hydraulic Pump 53 Filters 54 Accumulator 55 Hydraulic Cylinder 61 Excitation Brake 62 Non-excitation brake 63 Release lever 71 Battery Management Unit (BMU) J Inverter K Battery K1 48V Battery K2 24V Battery K3 12V Battery M Electric Motor R1 Front Wheel R2 rear wheel

Claims

1. A pair of compaction wheels are installed at the front and rear, A vehicle frame that rotatably supports the aforementioned compaction wheel, An electric motor for the compaction wheel that drives the compaction wheel, An inverter for the compaction wheel controls the rotation speed of the electric motor for the compaction wheel, A vibration shaft equipped with an eccentric weight is provided inside the rolling wheel, A vibration motor for driving the aforementioned vibration excitation shaft, A vibration inverter that controls the rotational speed of the aforementioned vibration electric motor, The electric motor for the compaction wheel, the inverter for the compaction wheel, the electric motor for vibration, and the battery that supplies power to the vibration inverter, It includes a control unit that outputs a signal to the vibration inverter in response to the operator's operation, It does not have an internal combustion engine, and the power source for the compaction wheel is solely the battery. The rotational speed of the vibration motor is controlled by the vibration inverter according to the operator's operation, and the intensity of the vibration can be adjusted according to the rotational speed, characterized in that the motor's rotational speed is controlled by the vibration inverter according to the operator's operation, and the intensity of the vibration can be adjusted accordingly.

2. A pair of compaction wheels are installed at the front and rear, A vehicle frame that rotatably supports the aforementioned compaction wheel, An electric motor for the compaction wheel that drives the compaction wheel, An inverter for the compaction wheel controls the rotation speed of the electric motor for the compaction wheel, A vibration shaft equipped with an eccentric weight is provided inside the rolling wheel, A vibration motor for driving the aforementioned vibration excitation shaft, A vibration inverter that controls the rotational speed of the aforementioned vibration electric motor, The electric motor for the compaction wheel, the inverter for the compaction wheel, the electric motor for vibration, and the battery that supplies power to the vibration inverter, It includes a control unit that outputs a signal to the vibration inverter in response to the operator's operation, It does not have an internal combustion engine, and the power source for the compaction wheel is solely the battery. The compaction wheel is rotatably supported via vibration-damping rubber provided on a pair of side plates located on the side of the vehicle frame. The electric roller is characterized in that the vibration-generating electric motor and the vibration-generating inverter are installed above the spring relative to the vibration-damping rubber.

3. The aforementioned battery comprises multiple batteries with different voltages. The electric roller according to claim 1 or 2, characterized in that the battery that supplies power to the electric motor for the compaction wheel, the inverter for the compaction wheel, the electric motor for vibration, and the inverter for vibration, and the battery that supplies power to the starter switch used during starting are configured separately.

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