JP3695371B2 - Motor driven tractor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an agricultural tractor driven by a motor.
[0002]
[Prior art]
Conventionally, most agricultural tractors have a diesel engine mounted on the front of the fuselage, where a radiator, muffler, battery, etc. are placed around the engine, and a transmission is installed in the transmission case at the rear of the fuselage. It was the structure which provided and transmitted the rotational power decelerated suitably with the transmission to the front wheel and the rear wheel.
[0003]
[Problems to be solved by the invention]
By the way, in the above-mentioned conventional apparatus, many expensive parts such as a radiator and a muffler are required, and the manufacturing cost is increased as a whole, and the vibration and noise are high, so that the working environment is deteriorated. was there. In addition, a small tractor sometimes enters a house to perform management work. However, in such work, there is a problem that exhaust gas is trapped in the house and the work cannot be performed for a long time. Therefore, a configuration in which the power source of the tractor is changed from a diesel engine to a battery is conceivable, but in the work of the tractor, the load fluctuates when the vehicle body moves forward and backward, and in particular, traveling using a motor driven by the battery When it was set as the structure to do, the subject that the vehicle speed was easy to fluctuate | deviate greatly with load fluctuations, and workability | operativity was bad.
[0004]
[Means for Solving the Problems]
The present invention has been proposed in view of the above problems, and the following technical means have been taken. That is, in a tractor having front and rear wheels (2) and rear wheels (3) at the front and rear of the fuselage, a battery (16) that can be charged to the fuselage and a traveling system alternating current that is driven by electric power stored in the battery (16). A motor (4), a forward / reverse switching lever (33) for switching forward and backward movement of the aircraft, a travel speed adjusting pedal (27), and a pair of left and right brake pedals for turning the aircraft by one-brake operation, When the travel speed adjusting pedal (27) is depressed, the frequency is changed in accordance with the depression amount. As a result, the rotational speed of the traveling AC motor (4) increases, and the forward / reverse switching lever (33) is operated forward and backward. When the traveling direction of the aircraft is changed while maintaining the vehicle speed set by the travel speed adjusting pedal (27) and the pair of left and right brake pedals (25, 26) are operated simultaneously, the travel system And a motor-driven tractor, characterized in that the rotational speed by changing the frequency provided controller (20) for controlling to decrease the flow motor (4).
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below based on the embodiments shown in the drawings. First, in terms of configuration, reference numeral 1 denotes a tractor, which includes a front wheel 2 and a rear wheel 3 at the front and rear portions of the fuselage. Is installed. The traveling power reduction gear box 5 is configured to transmit the rotational power appropriately reduced to the front wheels 2 and the rear wheels 3.
[0006]
A hydraulic pump 8 and a hydraulic tank 9 are provided at the rear upper part of the reduction gear box 5 in order to move the lift mechanism 6 at the rear of the machine up and down. Then, the hydraulic oil in the hydraulic tank 9 is sent by a hydraulic pump 8 to a hydraulic cylinder (not shown) provided in the rear mission case 10 to rotate the lift mechanism 6 up and down. A PTO AC motor 12 is mounted below the seat 11 and its output shaft is connected to the rear mission case 10. The PTO shaft 15 projecting from the rear end portion of the rear mission case 10 is rotationally driven via a PTO reduction gear mechanism (not shown) incorporated in the rear mission case 10.
[0007]
1 and 2, reference numeral 16 denotes a battery. These batteries 16 are arranged symmetrically on the body frame 18 so as to maintain a good balance in the left-right direction. A control controller 20 controls the rotation of the two AC motors 4 and 12. The upper part of the control controller 20 and the traveling system AC motor 4 is covered with a hood 22, and a solar cell 24 is attached to the upper surface of the hood 22 and the fender 23 that covers the rear wheel 3. The solar cell 24 is installed for the purpose of supplying power stored in the daytime to the battery 16.
[0008]
In FIG. 3, 25 and 26 are left and right brake pedals, 27 is a travel speed adjusting pedal, 28 is a speedometer, 29 is a PTO tachometer, and 30 is an indicator showing battery capacity. The side portion of the seat 11 is provided with a forward / reverse switching lever 33 for switching the forward / backward movement of the airframe, a rotation speed setting dial 35 for setting the PTO rotation speed, a lift operation lever 36 for raising / lowering the work machine, and the like. Yes. The traveling speed adjusting pedal 27 is configured so that the rotational speed of the traveling AC motor 4 changes according to the amount of depression, and the PTO rotational speed setting dial 35 is rotated by an operator. The rotational speed of the PTO shaft 15 is set.
[0009]
The rotational speed adjustment in this embodiment employs a method of changing the frequency, and the traveling system and PTO system can be adjusted in a stepless manner, but the rotational speed is adjusted. It may be something that can be done in stages. FIG. 4 is a block diagram for achieving the rotational speed control. The configuration thereof will be briefly described. On the input side of the microcomputer unit 40 constituting the controller 20, the amount of depression of the travel speed adjusting pedal 27 is detected. 41, brake pedal depression amount detection sensors 42 and 43, forward / reverse switching lever 33 operation detection SW 44, PTO setting dial 35, PTO rotation sensor 46, vehicle speed sensor 47, battery 16, solar cell 24, and the like are connected.
[0010]
On the other hand, on the output side of the microcomputer unit 40, together with the battery indicator 30, the PTO tachometer 29, and the speedometer 28, traveling system and PTO system AC motors 4 and 12 are connected. In the figure, between the battery 16 and the AC motors 4 and 12, forward / reverse units 50 and 51 for changing the rotation direction of the AC motors 4 and 12, and a DC / AC converter for converting DC to AC. 53 and 54 and AC / DC converters 56 and 57 for power recovery for recovering the back electromotive force from the AC motors 4 and 12 in the battery 16 are provided.
[0011]
Then, according to the control flow shown in FIG. 5, the rotational speed control of the traveling AC motor 4 and the rotational speed control of the PTO AC motor 12 are performed. The rotational speed control of the traveling system AC motor will be described based on the flowchart of FIG. During operation or when traveling on the road, the frequency of the AC motor 4 is set according to the amount of depression of the traveling speed adjustment pedal 27 (step S1). When both the left and right brake pedals 25 and 26 are not depressed and the brake flag is not set, the frequency becomes the initial setting value of the traveling AC motor 4 and depends on the state of the forward / reverse switching lever 33. Then move the aircraft forward and backward. That is, when the forward / reverse switching lever 33 is tilted forward, the forward / reverse unit 50 is switched to the forward rotation side (step S7). Conversely, when the forward / backward switching lever 33 is tilted backward, the forward / reverse unit 50 is switched to the reverse rotation side ( In step S8, the set frequency is output to the DC / AC converter 53, and the AC motor 4 is driven at the set rotational speed (step S9).
[0012]
When the left and right brake pedals 25, 26 are connected and depressed simultaneously to stop the aircraft, the frequency is changed to reduce the vehicle speed. In this case, the frequency for decelerating the traveling AC motor 4 is reset again according to the depression amount of the brake pedals 25 and 26 (step S3), and at the same time, the brake flag is set and the frequency at this time is stored. (Step S4). Then, as in the case described above, the aircraft stops, moves forward, or moves backward according to the position of the forward / reverse switching lever 33.
[0013]
Since the decelerated speed is given priority even when the brake pedals 25 and 26 are released, in order to cancel this, the operator once depresses the traveling speed adjusting pedal 27 to the decelerating side to adjust the traveling speed. A so-called safety operation is required to match the speed (frequency) setting by the pedal 27 with the speed (frequency) in the deceleration state set by depressing the brake pedals 25 and 26 (steps S10 and S11).
[0014]
By performing this coincidence operation, the brake flag is returned to the reset state (step S12). Thereafter, the operation by the traveling speed adjustment pedal 27 is given priority, and the vehicle speed is maintained at the speed set by the pedal 27. (Step S13). By incorporating the safety mechanism in this way, it is possible to prohibit the rapid acceleration of the aircraft when the brake operation is interrupted and to improve safety.
[0015]
In this embodiment, when the brake pedals 25 and 26 are depressed at the same time, a brake device (not shown) is configured to operate, and the drive frequency itself of the AC motor 4 is controlled to reduce the vehicle speed. Therefore, the aircraft can be stopped quickly and the brake burn-in phenomenon can be prevented. Also, since the deceleration effect does not occur in one-brake operation and the vehicle speed is reduced only when both brake pedals 25 and 26 are operated, the vehicle speed is extremely reduced during turning by one-brake operation, and workability is improved. There is no problem of deteriorating.
[0016]
Finally, the flowchart of FIG. 7 relates to PTO control. First, the rotational speed of the PTO shaft 15 is set by rotating the PTO rotational speed setting dial 35 (step # 1). Then, the actual rotational speed detected by the PTO rotation sensor 46 is compared with the rotational speed set by the dial 35 (step # 2), and the drive frequency is adjusted according to the difference (step # 3). At this time, AC motor 12 is rotated forward or backward depending on the deviation and its direction (steps # 4, # 6, and # 7). For example, the rotational speed of PTO shaft 15 is increased to maintain a predetermined value. When the speed is to be increased, the forward / reverse unit 51 is switched to the forward rotation side, the frequency necessary for maintaining the rotation is set in the DC / AC converter 54 (steps # 6 and # 8), and the speed is reduced on the contrary. Then, the forward / reverse unit 51 is switched to the reverse side, and the DC / AC converter 54 is set with a frequency necessary for maintaining a predetermined rotation (steps # 7 and # 8).
[0017]
【The invention's effect】
Since the present invention is configured as described above, the following technical effects can be obtained. That is, in a tractor having front and rear wheels (2) and rear wheels (3) at the front and rear of the fuselage, a battery (16) that can be charged to the fuselage and a traveling system alternating current that is driven by electric power stored in the battery (16). A motor (4), a forward / reverse switching lever (33) for switching forward and backward movement of the aircraft, a travel speed adjusting pedal (27), and a pair of left and right brake pedals for turning the aircraft by one-brake operation, When the travel speed adjusting pedal (27) is depressed, the frequency is changed in accordance with the depression amount. As a result, the rotational speed of the traveling AC motor (4) increases, and the forward / reverse switching lever (33) is operated forward and backward. When the traveling direction of the aircraft is changed while maintaining the vehicle speed set by the travel speed adjusting pedal (27) and the pair of left and right brake pedals (25, 26) are operated simultaneously, the travel system Since the motor driven tractor is provided with a controller (20) that controls the rotational speed to be decreased by changing the frequency of the flow motor (4), compared with the case of working with a diesel engine. Vibration and noise are reduced, the work environment is not deteriorated, and even if load fluctuation occurs during forward / reverse switching, the speed is maintained at the set vehicle speed and workability is not impaired.
In addition, when the pedal for adjusting the traveling speed (27) is depressed, the traveling speed of the aircraft can be changed as if the accelerator pedal is depressed in the same manner as a normal tractor equipped with a diesel engine. Even if the vehicle is stepped on, the vehicle speed is not reduced, but is reduced only when the vehicle is stepped on the left and right at the same time, so that workability is good and work efficiency is not reduced.
[Brief description of the drawings]
FIG. 1 is a side view of a tractor.
FIG. 2 is a plan view of the tractor.
FIG. 3 is a plan view of the main part of the tractor.
FIG. 4 is a control block diagram.
FIG. 5 is a flowchart of overall control.
FIG. 6 is a control flowchart of a traveling system.
FIG. 7 is a control flowchart of a PTO system.
[Explanation of symbols]
1 Tractor 2 Front wheel 3 Rear wheel 4 AC motor (travel system)
6 Lift mechanism 12 AC motor (PTO system)
15 PTO shaft 16 Battery 20 Control controller

Claims (1)

In a tractor equipped with front and rear wheels (2) and rear wheels (3) at the front and rear of the fuselage, a battery (16) that can be charged to the fuselage and a traveling AC motor (driven by electric power stored in the battery (16)) 4), a forward / reverse switching lever (33) for switching forward / backward movement of the aircraft, a travel speed adjusting pedal (27), and a pair of left and right brake pedals for turning the aircraft by one-brake operation, When the adjustment pedal (27) is depressed, the frequency is changed according to the depression amount. As a result, the rotational speed of the traveling AC motor (4) increases, and when the forward / reverse switching lever (33) is operated forward and backward, the traveling speed is increased. When the traveling direction of the aircraft is changed while maintaining the vehicle speed set by the adjusting pedal (27) and the pair of left and right brake pedals (25, 26) are operated simultaneously, the traveling system AC mode Motor (4) Motor-driven tractor, characterized in that the rotational speed by changing the frequency provided controller (20) for controlling to decrease the.

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