Running device

Abstract

To solve that problem that in a running vehicle having a conventional structure, its weight and a steering device (steering angles of front wheels) are subjected to restriction and mechanically-determined rotation speed ratios of wheels are subjected to restriction, which very often destroys a soil surface and a plow pan when the vehicle turns (veers) and in the worst case, the vehicle becomes unable to run, when running on a soft farm field such as a paddy field in particular.SOLUTION: A wheel driving mechanism composed of an electric motor for driving wheels and a deceleration device are arranged near respective wheel axes thereof (generally called [an in-wheel motor]), and the wheels and the wheel driving mechanism are supported to be integrally turnable with a shaft nearly perpendicular to a wheel grounding point as a center, and further the turning (steering) is performed by the electric motor through a deceleration device for steering. A plurality of wheel-type running device structures in which the wheel, the wheel driving mechanism, the electric motor for steering and the deceleration device for steering are integrally formed are supported so that positions thereof can be changed in a longitudinal direction (device advancing direction) or in a lateral direction (device width direction) with respect to a running body.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention mainly relates to a traveling device that can travel accurately and efficiently (with low energy consumption) within a field for growing crops.

Background Art

[0002] As this type of traveling device, vehicles such as those shown in Published Patent Gazette 2022-9673, 2022-101317, or 2023-058587 are known. Various devices are described in these to achieve automatic traveling within a field or to accommodate the width of ridges on which crops grow.

[0003] Many of the traveling devices and steering devices shown in these devices are characterized by the structures of tractors and rice transplanters that have been conventionally commercially available, namely, driving by an internal combustion engine, speed change and deceleration by a transmission, front-wheel steering, and relatively wide wheels.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005]

Patent Document 2

[0006]

Patent Document 3

[0007]

Patent Document 4

[0008]

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0009] In the traveling devices as shown in Patent Documents 1, 2, and 3 above, since they follow the basic structures of conventionally commercially available tractors and riding rice transplanters, generally many use internal combustion engines as prime movers, and many transmit the power to the wheels through power transmission mechanisms such as transmissions and reduction mechanisms.

[0010] In the conventional structure, due to its weight, the constraints of the steering device (steering angle of the front wheels), the constraints of the rotation speed ratio of each wheel determined mechanically, etc., especially when traveling on soft fields such as paddy fields, the soil surface and plow pan are often damaged during turning (direction change), and in the worst case, it may fall into an inoperable state. Even in the electrified ones, they are just structures that replace the conventional internal combustion engine with an electric motor and a battery, and have not achieved problem-solving.

[0011] Also, Patent Document 4 shows an electric wheelchair with an electric motor and a reduction device arranged on the axle, and Patent Document 5 shows an example of a self-propelled sweeper, but they are not capable of traveling in fields such as paddy fields.

[0012] The present invention enables accurate and efficient traveling without significantly damaging the soil surface and plow pan even under field conditions such as flooded paddy fields as well as fields where crops are growing.

Means for Solving the Problems

[0013] The traveling device according to the present invention arranges a wheel drive mechanism composed of a wheel drive motor and a speed reduction device near each axle (generally called an "in-wheel motor"), and integrally supports the wheel and the wheel drive mechanism so as to be rotatable about an axis substantially perpendicular to the wheel contact point. Further, this rotation (steering) is performed by an electric motor via a steering speed reduction device. (For the purpose of improving straight running performance, etc., those in which this rotation axis is slightly inclined from the vertical are included in "substantially perpendicular".)

[0014] A wheel-type traveling device mechanism (hereinafter referred to as a "wheel unit") in which the above-described wheel, wheel drive mechanism, steering electric motor, and steering speed reduction device are integrally configured, and these wheel units are supported so that their positions can be changed in the front-rear (machine body traveling direction) or left-right (machine body width direction) directions with respect to the traveling machine body.

Effects of the Invention

[0015] According to the present invention, the rotational speed and steering angle of the wheels can be set to an optimal state for each wheel individually, and a power transmission device such as a large and heavy transmission as in the prior art is not required, so the weight can be reduced and the ground pressure can be reduced, enabling accurate and efficient traveling even on soft soil conditions such as paddy fields.

[0016] In addition, due to the weight reduction, the energy consumption for traveling is reduced, so in the further electrification that is expected in the future, the battery mounted can be made smaller for the required working time, thus shortening the charging time.

[0017] Since accurate traveling along the rows and ridges of crops is possible, by grasping the position of the machine body using GPS or the like and controlling each wheel by computer control, it becomes possible to further expand the range of unmanned traveling work.

Brief Description of the Drawings

[0018]

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BEST MODE FOR CARRYING OUT THE INVENTION

[0019] FIG. 1 shows a four-wheel drive type traveling device according to the present invention. Wheel units 1.2 are arranged on the front, rear, left, and right of a frame-shaped airframe frame 1.1, and each wheel unit is fastened and fixed with fixing bolts 1.3 so as to sandwich the horizontal frame of the airframe frame.

[0020] By loosening these fixing bolts 1.3, the wheelbase (tread) can be adjusted according to the rows and widths of agricultural crops.

[0021] The body frame 1.1 is divided into two parts, the front frame 1.4 and the rear frame 1.5, and the front and rear frames are connected by a pipe insertion structure. This insertion part is fixed by bolts 1.6.

[0022] By loosening these bolts 1.6, the wheelbase can be adjusted according to the weight of the working machine and the size of the field.

[0023] Figures 2, 3, and 4 are perspective view, side view, and front view of the "wheel unit" according to the present invention. Also, Figure 5 is a cross-sectional view of the wheel drive part. A wheel drive mechanism 2.3 composed of a motor 5.1 and a speed reducer 5.2 is arranged near the central axle 2.2 of the wheel 2.1, and it is supported by an inverted U-shaped member 2.4. The upper part of this member is rotatably supported about an axis 2.6 that is substantially perpendicular to the wheel contact point 2.5. This rotation (steering) operation is performed by a steering motor 2.8 via a steering speed reducer 2.7.

[0024] The seal member 5.3 serves to protect components such as the electric motor and speed reducer for wheel drive from rainwater and muddy water in the field. To further enhance this effect, air is sent in by a pipe 5.4 to make the internal air pressure slightly higher than the atmospheric pressure. The internal air pressure partitioned by the seal member through holes 5.5 provided in the internal partition walls is kept substantially constant in each room. This air is pressure-fed by a separately provided electric air pump, but the illustration is omitted.

[0025] In this illustrated example, both for wheel drive and steering, the electric motor and the planetary gear type speed reducer are arranged on the same axis, but in the case of speed reduction by other methods, they do not have to be on the same axis. Although not shown in this example, the battery or controller for electric motor drive may be individually arranged for each of these units.

[0026] Figure 6 is an enlarged view of the part where the wheel unit 1.2 is fixed to the horizontal frame 6.1 (composed of two round pipes in this example) of the body frame 1.1.

[0027] Figure 7 is an enlarged view of the connecting and fixing part between the front frame and the rear frame that constitutes the airframe frame. In this example, it is fixed at a total of four locations with 1.6 bolts.

[0028] Figure 8 is a detailed view inside the steering reduction gear (shown as a semi-transparent exploded view). In this example, a two-stage planetary gear device is used to obtain a predetermined reduction ratio. In addition, in this example as well, the motor 2.8 and the reduction gear 2.7 are arranged on the same axis, but when using other types of reduction devices (such as a worm and a worm wheel, etc.), they do not need to be on the same axis.

[0029] Figure 9 shows an embodiment in which a commercially available rice transplanter planting device 9.1 is mounted as a working machine on the traveling unit shown in Figure 1. The height with respect to the field surface 9.3 can be changed by the lifting link 9.2. Also, by installing the motor 9.4 on the side of the planting working machine, there is no need to connect and arrange a drive shaft from the main body side of the traveling unit. Therefore, not only is the degree of freedom in arranging the working machine increased, but the planting pitch (plant spacing) can also be steplessly changed by changing the rotational speed of the motor.

[0030] Figure 10 is a plan view of an embodiment in which a weeding machine 10.1 mainly for intertillage weeding during the growth of rice is mounted on the central part of the airframe. According to the above-described adjustment structure, the wheelbase and the axle distance can be changed according to the dimensions and working content of the working machine to be mounted. It should be noted that it is also possible to arrange working machines such as the previous rice transplanter here using the lifting link in this figure. (In this example, the tread 10.2 of the front wheels is widened, the tread 10.3 of the rear wheels is narrowed, and the wheelbase 10.4 is extended.)

[0031] An embodiment when no working machine is mounted is shown in Figure 11. A loading platform 11.1 is provided on the airframe frame and can be used as a transport vehicle or a harvesting assistance vehicle for vegetables, etc.

[0032] Figure 12 shows an example of the operation part when a person rides and operates. The operation amount signal from an operation lever (generally called a joystick) that can be operated with the fingertips is transmitted to the electric motor for driving the wheels and the electric motor for steering via the main computer (main controller). In this example, a running operation lever 12.1 is provided on the right side of the driver's seat, an emergency stop switch 12.2 is provided in the vicinity thereof, and a working machine operation lever 12.3 is provided on the left side of the driver's seat. (Illustration of electrical wiring is omitted.)

[0033] Figure 13 is a block diagram of a system that enables unmanned (automatic) driving, and Figure 14 shows the arrangement of a battery 14.1, each controller, and a GPS (Global Positioning System) receiver 14.2. The GPS receiver recognizes the position, and the driving trajectory operated by a person is recorded and stored in a computer (main controller) 14.3, and the trajectory is followed during automatic driving. Also, by taking in map information in advance, the size and shape of the field can be recognized, and the driving trajectory can be determined by them. In addition, for ensuring safety, since the operation lever and the emergency stop switch may be operated during automatic driving, the priority should be in the order of the emergency stop switch signal, the operation lever signal, and the automatic driving signal. The power controller 14.4 mainly performs power supply to each part and battery management. Note that 14.5 is a stroke sensor for detecting the set wheelbase.

[0034] Figure 15 shows the trajectories of the wheels during a left turn. For a required turning radius, if the wheelbase WB and the tread T are determined, the trajectories of the left front wheel 15.1, the right front wheel 15.2, the left rear wheel 15.3, and the right rear wheel 15.4 are uniquely determined. The input of the values of the wheelbase and the tread to the computer can be manual input or the values can be automatically taken in from respective sensors. By appropriately giving the steering angle (in this example, only the front wheels are steered) and the rotational speed of each wheel that matches this trajectory under the control of the computer (main controller), an accurate and efficient turn that does not damage the soil or the plow can be achieved.

[0035] This description is based on a four-wheel drive and four-wheel steering vehicle that has the same wheel units on the front, rear, left, and right as shown in Figure 1. However, depending on the usage conditions, the same effect may be obtained even if the steering function on either the front or the rear is abolished. If cost is prioritized, such a structure can also be considered.

Explanation of Symbols

[0036] 1.1 Traveling body (body frame) 1.2 Wheel-type traveling device mechanism (wheel unit) 1.3 Wheel unit fixing bolt 1.4 Front frame 1.5 Rear frame 1.6 Body frame fixing bolt 2.1 Wheel 2.2 Axle 2.3 Wheel drive mechanism 2.5 Wheel contact point 2.7 Steering reduction gear 2.8 Steering motor

Claims

1. A wheel drive mechanism composed of an electric motor for driving wheels and a speed reduction device is arranged near the axle, and the wheels and the wheel drive mechanism are integrally rotatably supported about an axis substantially perpendicular to the wheel contact point. Further, this rotation (steering) operation is performed by an electric motor via a steering speed reduction device. An electric vehicle equipped with a plurality of wheeled traveling device mechanisms.

2. A wheeled traveling device mechanism in which the above-mentioned wheels, wheel drive mechanism, steering electric motor, and steering speed reduction device are integrally configured is supported so that its position can be changed and fixed in the front-rear (vehicle body traveling direction) or left-right (vehicle body width direction) direction, or both front-rear and left-right directions with respect to the traveling body. An electric vehicle characterized by this.

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