Electric running vehicle

Abstract

To provide an electric running device that can accurately and efficiently run without destroying a soil surface and a plow pan largely, under a condition of a farm field such as a dry field on which crops are grown naturally and a flooded paddy field.SOLUTION: A wheel driving mechanism composed of an electric motor for driving wheels and a deceleration device is arranged near wheel axes, and front wheels or rear wheels, or left and right wheels of the front and rear wheels and the wheel driving mechanism are supported to be integrally turnable with a shaft which is nearly perpendicular to a center of a left / right wheel grounding point as a center, and further operation of the turning (steering) is performed based on a difference in rotation speed between the left and right wheels. A wheel-type running device in which the wheels and the wheel driving mechanism are integrally formed is supported at a position higher from the ground than upper ends of diameters of the wheels, and a wheel track (tread) or a wheel track (wheel base), or both of the trad and the wheel base can be changed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention mainly relates to an electric vehicle capable of traveling accurately and efficiently (with low energy consumption) within a farm field for growing crops.

Background Art

[0002] As vehicles of this type, for example, vehicles such as those shown in Published Patent Gazette 2022-9673, 2022-101317, or 2023-058587 are known. Various devices for realizing automatic driving within a farm field or for accommodating the width of ridges (furrows) where crops grow are described in these.

[0003] Many of the vehicles and steering devices shown in these devices are generally characterized by the structure of conventional commercially available tractors and rice transplanters, that is, driving by an internal combustion engine, speed change and deceleration by a transmission, steering by the front wheels, 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 vehicles 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 relatively large-diameter wheels through power transmission mechanisms such as transmissions and reduction mechanisms.

[0010] In the conventional structure, due to its overall 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, when turning (changing direction), the soil surface and plow layer are often damaged, 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 layer even under field conditions such as flooded paddy fields as well as arable 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 reduction device near each axle (generally referred to as an "in-wheel motor"), and integrally supports the wheel and the wheel drive mechanism so that they can rotate about an axis substantially perpendicular to the center of the left and right wheel contact points. Further, this rotation (steering) is performed by the rotational speed difference between the left and right wheels. (For the purpose of improving straight running performance, etc., those with the rotation axis slightly inclined from the vertical are included in "substantially perpendicular".)

[0014] The wheel-type traveling device in which the above-described wheel and wheel drive mechanism are integrally configured is supported at a position higher than the ground with respect to the upper end of the wheel diameter and substantially on the vertical line of the wheel contact point, and can be changed in position in the left-right (machine body width direction) with respect to the traveling machine body. At the same time, the wheelbase (tread) and the axle distance (wheelbase) can be changed.

Effect 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 large and heavy power transmission device such as a conventional transmission is not required, so the weight can be reduced and the ground pressure can be reduced. It becomes possible to run accurately and efficiently even on soft soil conditions such as paddy fields.

[0016] In addition, since the steering operation is performed by the rotational speed difference between the left and right steering wheels, even at low speeds, the amount of soil moved during steering is small and smooth steering with less energy loss is possible without separately mounting a power device for steering. Due to the weight reduction effect, the energy consumption for traveling is also reduced. Therefore, even in the future electrification that is expected to progress further, the battery mounted can be made smaller for the required working time, and the charging time can be shortened.

[0017] Since the wheel-type traveling device in which the above-described wheel and wheel drive mechanism are integrally configured is supported at a position higher than the ground with respect to the upper end of the wheel diameter and substantially on the vertical line of the wheel contact point, it is possible to travel without damaging the crops even if the height of the crops is about the wheel diameter.

[0018] Since it is possible to drive accurately along the rows and ridges of crops, while grasping the position of the aircraft using GPS etc., by adjusting the rotational speed of each wheel and steering by computer control, it becomes possible to further expand the range of unmanned driving operations.

Brief Description of the Drawings

[0019]

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Modes for Carrying Out the Invention

[0020] Figure 1 shows a four-wheel drive traveling device according to the present invention. Front wheels 1.2 are arranged on the front side (left side in the figure) of the body frame 1.1, and rear wheels 1.3 are arranged on the rear side (right side in the figure). In this example, the front wheels will be described as for steering.

[0021] The body frame 1.1 is divided into two parts, a front frame 1.4 and a 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 (axle distance) can be adjusted according to the weight of the working machine and the size of the field.

[0023] Figure 2 is a perspective view of the "wheel-type traveling device" according to the present invention. The wheel drive mechanism 2.3 and the wheel 2.1 are supported by an inverted U-shaped member 2.4, and an attachment and fixing portion 2.6 to other components is provided above the inverted U-shaped member. Figure 3 shows the details of the attachment portion. In this example, pipes are clamped and fixed by the recessed portions 3.1 and 3.2 provided vertically. By loosening the upper fixing bolts, the tread (wheel track) can be adjusted according to the ridge width of the crops. 2.5 is the ground contact point of the wheel.

[0024] Figure 4 is a cross-sectional view of the wheel drive part. The wheel drive mechanism 2.3 composed of an electric motor 4.1 and a speed reducer 4.2 is arranged near the central axle 2.2 of the wheel 2.1. The seal member 4.3 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 4.4 so that the internal air pressure is slightly higher than the atmospheric pressure. The internal air pressure partitioned by the seal member through the holes 4.5 provided in the internal partition wall is kept almost constant in each room. This air is pressure-fed by a separately provided electric air pump, but the illustration is omitted.

[0025] In this illustration, the electric motor and the planetary gear type 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, a battery or a controller for driving the electric motor may be individually arranged for each of these driving parts.

[0026] FIG. 5 is a perspective view of the front wheel part used for steering, and FIG. 6 is a front view thereof. The wheel type traveling device is fastened and fixed to a plurality of pipe members 5.1, and the left and right wheels and their pipe members are integrally rotatable about a shaft 5.2. Further, the rotation shaft is supported by an inverted U-shaped member 5.3 from above, and the whole is supported by a shaft 5.4 so as to be rotatable about a vertical line passing through substantially the middle position 6.1 of the ground contact points 2.5 of the left and right wheels. The limit angle of rotation around the shaft 5.2 is determined by the gap 6.2.

[0027] Steering is performed by giving a speed difference to the drive electric motors of the left and right wheels. That is, for example, if the rotational speed of the right wheel 5.5 is increased with respect to the left wheel 5.6, the whole rotates counterclockwise in a top view about the shaft 5.4, and steering can be performed without applying a separate force for steering.

[0028] FIG. 7 is a perspective view showing the structure of the rear wheel part (non-steering side). Each wheel type traveling device is supported independently on the left and right by a pipe material 7.1, and the pipe material is supported so as to be rotatable about a shaft 7.2 integrally with the fixed wheel type traveling device. The rotatable range is restricted by a cushion rubber 7.3 provided near the pipe end and a U-shaped member 7.4. A simple suspension function is provided by this cushion rubber 7.3.

[0029] FIG. 8 is a perspective view of the entire traveling part. By supporting the support shaft 5.4 of the front wheel part on the frame 1.1 via a cushion rubber 8.1, a suspension effect is imparted to the front wheel.

[0030] Figure 9 is a perspective view of an embodiment in which a weeding machine 9.3 mainly for intertillage weeding during rice growth is mounted on the rear of a vehicle body equipped with a floor 9.1 for riding on the body frame and a transparent driver protection shield 9.2 via a work implement lifting link 9.4.

[0031] Figure 10 shows an embodiment in which the upper structure is mounted on the traveling unit with the front and rear reversed. In this case, the work implement 10.1 is on the front side and the rear wheels 1.2 are for steering.

[0032] Figure 11 shows an embodiment of the operation part when a person rides and operates. The operation amount signal from an operation lever (generally called a joystick) operable with fingertips is transmitted to the electric motor for driving the wheels and the work implement via a main computer (main controller). In this example, a traveling operation lever 11.1 is provided on the right side of the driver's seat, an emergency stop switch 11.2 is provided in the vicinity thereof, and a work implement operation lever 11.3 is provided on the left side of the driver's seat. (Illustration of electrical wiring is omitted)

[0033] Figure 12 is a block diagram of a system that enables unmanned (automatic) driving. Figure 13 shows the arrangement of a battery 13.1, each controller 13.3, 13.4, and a GPS (Global Positioning System) receiver 13.2. The GPS receiver recognizes the position and records and stores in a computer (main controller) 13.3 the traveling trajectory previously operated (taught) by a person, and follows the trajectory during automatic driving. Also, by taking in map information, the size and shape of the field can be recognized, and the traveling trajectory can be automatically determined based on them. Note that for ensuring safety, since the operation lever or the emergency stop switch may be operated during automatic driving, the priority order should be the emergency stop switch signal, the operation lever signal, and the automatic driving signal in that order. The power controller 13.4 mainly supplies power to each part and manages the battery.

[0034] Figure 14 shows the trajectory of the wheels during a left turn. For a required turning radius, once the respective track (tread) T1, T2, wheelbase (WB), and the center of the turn P1 are determined, the trajectories R1, R2, R3, R4 of the left front wheel 14.1, right front wheel 14.2, left rear wheel 14.3, and right rear wheel 14.4 required for the turn are uniquely determined. During a turn, by controlling a computer (main controller) to provide the rotational speed of each wheel proportional to these radii, an accurate and efficient turn can be achieved without damaging the soil or the tillage pan.

[0035] The values of the tread and wheelbase may be manually input into the computer (main controller), or sensors may be provided at each adjustment section so that the values are automatically captured. As an example, Figure 13 shows an angle sensor 13.5 and a wheelbase sensor (stroke sensor) 13.6 for sensing the steering angle and the value of the wheelbase, and Figure 12 shows the signals from them and the connections of each part.

Explanation of Signs

[0036] 1.1 Traveling body (body frame) 1.2 Wheeled traveling device (front wheel) 1.3 Wheeled traveling device (rear wheel) 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 2.6 Steering reduction gear 2.8 Steering motor

Claims

1. A wheel drive mechanism consisting of an electric motor for driving wheels and a speed reduction device is arranged near the axle, and the left and right wheels of the front or rear wheels and the wheel drive mechanism are integrally rotatably supported about an axis substantially perpendicular to the center of the ground contact points of the left and right wheels. Further, this rotation (steering) operation is performed by the rotational speed difference between the left and right wheels. An electric vehicle equipped with a wheeled traveling device characterized by this.

2. The wheeled traveling device in which the above-described wheels and wheel drive mechanism are integrally formed is supported at a position higher than the ground with respect to the upper end of the wheel diameter, and can be fixed in a position change in the left-right (machine body width direction) with respect to the traveling body. An electric vehicle characterized by this.

3. The wheeled traveling device in which the above-described wheels and wheel drive mechanism are integrally formed is arranged in the front and rear of the machine body, and the distance between the front and rear wheels can be changed and fixed. An electric vehicle characterized by this.

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