JPH0134578B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a vehicle speed control device that appropriately controls vehicle speed during harvesting work in a combine harvester that travels in a field, reaps grain culms planted in the field, and threshes the harvested grain culms. . Conventionally, as shown in, for example, Japanese Unexamined Patent Publication No. 53-58335, it has been known to provide a threshing section with a plurality of load detectors for control. But this is
Since control is only performed based on load detection, if the load is light, the speed will be increased anyway. Therefore, even when the sorting was not good, the speed was increased, making the sorting even worse. The present invention gives priority to control based on the degree of sorting, and performs control based on the load as an auxiliary, thereby achieving the original purpose of threshing with less loss and, in addition, efficient work at the same time. The structure of the vehicle speed control device for a combine harvester according to the present invention will be explained with reference to the embodiment shown in FIGS. 1-7. The combine harvester shown in FIG. While the machine is running, the grain culms to be planted in the field are divided by the grass division plate 2 at the frontmost part, and the grain culm lifter is raised slightly backward from the position of the grass division plate 2. The planted grain culm is harvested at the base of the plant by the cutting blade 4 at the rear of the dividing plate 2, and the harvested grain culm is conveyed vertically by the horizontal conveyance belt 5 and on the side of the plant base and the tip side. The belts 6 and 7 transport the grain toward the threshing section 8 on the machine body, and the feed chain 9 along one side of the threshing section 8 transports the harvested grain culm backwards.
Supplying the tip side of the harvested grain culm into the threshing section 8,
A combine harvester configured to perform threshing and to send the threshed grains to a top picker 10 on the other side of the machine after sorting,
Note that the feed chain 9 is provided with a rear-upward extension 9a so that the waste straw leaving the threshing section 8 is carried out by the extension 9a, and an engine 11 constituting a driving source is The present invention is implemented as follows in a combine harvester mounted on the rear of one side of the fuselage. That is, for convenience of explanation, first, the configuration of the threshing section 8 and the sorting section 12 that sorts the threshing parts from the threshing section 8 in the illustrated combine harvester will be briefly explained with reference to FIG. In the threshing section 8, a handling barrel 13 is rotatably provided with its axis extending in the longitudinal direction of the machine body, and the handling barrel 13 is rotatably driven by transmission from the engine 11 via an appropriate transmission mechanism. 13 separates the grain from the tip of the harvested grain culm and threshes it using a large number of handling teeth 14 installed thereon. Also, sorting section 1
2 is first equipped with a crimp net 15 located below the above-mentioned handling cylinder 13, and this crimp net 15 collects grain culms and fine straw waste etc. is allowed to leak, and non-leakable materials are discharged from the dust outlet at the rear end of the crimp net 15. From the bottom to the rear of the crimp net 15, a swinging sorting mechanism is provided which includes a feed van 16 from the front to the rear, a chaff sheave 17 and a grain sheave 18 arranged vertically in parallel, and a stroke rack 19. A winch 20 and a dust exhaust fan 21 are provided at the front and rearmost positions of the lower part, respectively. The above-mentioned swing sorting mechanism 16-19 is made to swing vertically, and as the feed van 16 at the forefront of the mechanism swings, the leakage material from the crimp net 15 is conveyed rearward. Sort heavy grains to the bottom layer and light straw waste to the top layer. From the grains falling from the feed van 16 to the chaff sieve 17, straw waste is further removed by the sorting air sent from the winnower 20, and the above-mentioned grains are sorted again by passing through the chaff sieve 17. A finer grain sieve 18 leaks from the grain sieve 17, and is fed to the first port 22 in a carefully selected state by receiving the sorting wind from the winnower 20 during that time. Also, from Feed Ban 16 to Karaki 2
From the straw waste that is transferred onto the straw rack 19 with the help of zero wind, as the straw rack 19 swings, mixed grains are separated forward and transferred onto the chaff sheave 17, The ear pieces and some of the grains are separated into the lower layer and fed to the lower second port 23 through the through holes of the straw rack 19. In the swinging sorting mechanism shown in FIG. 2, an upper stroke rack 24 is provided above the stroke rack 19 described above, and the upper stroke rack 24 is swung to assist the sorting action of the stroke rack 19 described above. The plan is to encourage the removal of straw waste. Due to the action of the stroke rack 19 itself, the suction wind of the dust exhaust fan 21, and furthermore the sorting wind from the winnower 20, the straw waste leaving the stroke rack 19 is discharged toward the rear of the machine from the No. 3 dust exhaust port 25. Ru. The grains supplied to the first port 22 as described above are conveyed toward the other side of the machine by the first conveyor 26 in the first port 22, and are transferred to the top feeder 10 by a grain frying conveyor (not shown). It will be done. Further, the ear chips and the like supplied to the second slot 23 as described above are returned to the threshing section 8 by the second thrower 27, and are reprocessed in the threshing section 8. In order to detect the load acting on the threshing section 8, the following threshing load detector is provided. That is, in the illustrated case, this detector is configured as a handling drum rotation speed detector 28 that detects the rotation speed of the handling drum 13, and as shown in FIG. is installed on top. As shown in FIG.
It is equipped with a rotor 29 which is fixed to the shaft 13a and rotates integrally with the handling cylinder shaft 13a, and on the inner peripheral surface of the drum-shaped rotor 29, a plurality of magnets 30 are arranged at equal intervals in the circumferential direction. It is fixed. The handling cylinder rotation speed detector 28 is further provided with a fixed position reed switch 31 installed opposite to the rotor 29, as shown in FIG. An integrator 32 is provided for integrating the output voltage from 31. The reed switch 31 has one terminal connected to the power supply terminal and the other terminal grounded, and as the rotor 29 rotates, each time the magnet 30 in the rotor 29 passes the reed switch 31 position, Magnetically turned on.
An amplifier 33 is connected to the integrator 32, and the members 20-33 form a handling cylinder rotation speed detection circuit _C1 .
The rotation speed of the handling cylinder 13 is increased or decreased as the load on the handling cylinder 13 increases or decreases, and the handling cylinder rotation speed detection circuit _C1 outputs a voltage signal proportional to the rotation speed of the handling cylinder 13 at its output terminal. Output Vrev. In order to detect the degree of threshing sorting by the sorting section 12, the following sorting degree detector is provided.
That is, in the illustrated case, this detector is constituted by a grain loss detector 34 that detects the number of grains contained in the dust discharged from the third dust exhaust port 25, in other words, the amount of grain loss. As shown in FIG. 2, it is installed to hang down from the upper edge of the dust exhaust end of the third dust exhaust port 25 so as to be inclined rearward and downward. The grain loss detector 34 is equipped with a piezoelectric element such as a piezoelectric ceramic disk, and is configured to output voltage spikes or voltage pulses corresponding to the pressure when it receives pressure. Therefore, when the dust discharged from the third dust exhaust port 25 hits the surface of the detector 34 and receives pressure, the grain loss detector 34 generates a voltage pulse with a frequency and amplitude corresponding to the pressure. Output. Naturally, such voltage pulses, as shown in pulses P ₁ and P ₂ illustrated in FIG. Different frequencies. No. 3 Sorting unit 12 based on the amount of lost grains discharged as waste
In order to check the sorting state of the detector, a bandpass filter 35, which is connected to the main body of the Glenn loss detector 34 and constitutes a part of the detector 34, is provided as shown in FIGS. 3 and 6. ing. As shown in FIG. 3, this bandpass filter 35 filters only the voltage pulse P ₁ with a frequency corresponding to grains, and the voltage pulse P ₂ corresponding to straw waste etc.
This is cut and not transmitted to the secondary side. As shown in FIG. 6, an amplifier 36 is provided connected to the bandpass filter 35 to amplify the voltage pulse P ₁ corresponding to the grain. , when a voltage pulse from the amplifier 36 is input, the monomulti 3 is turned on for a certain period of time and outputs a rectangular voltage pulse of a certain frequency and amplitude.
7 is provided. An integrator 38 is connected to the monomulti 37 and integrates the output pulse of the monomulti 37.
An amplifier 39 is provided connected to 8, and the above members 34-39 form a Glenn loss detection circuit _C2 . As described above, the degree of threshing sorting in the sorting section 12 is taken from the amount of grains in the third waste, and the grain loss detection circuit C ₂ outputs a voltage signal Vloss proportional to the amount of grains lost at its output terminal. Output. Next, for the sake of explanation, the configuration of the traveling drive section of the illustrated combine harvester will be explained. The drive wheel 40 that drives the crawler 1 receives rotational drive from the drive section inside the transmission case 41 shown in FIG. , the drive section in the transmission case 41 is constructed with a hydrostatic transmission shown in FIG. That is, as shown in FIG. 5, a variable displacement hydraulic pump 42 driven by the engine 11 and a fixed displacement hydraulic motor 43 which are interlocked and connected in the direction of the drive wheels 40 are connected. These hydraulic pumps 42 and hydraulic motors 43 are connected by a pair of oil supply/drainage circuits 44 and 45 that form a closed circuit, and the gear shift lever 46
By changing and adjusting the angle of the swash plate 42a of the hydraulic pump 42 through the operation, the oil discharge direction and discharge amount of the hydraulic pump 42 are changed and controlled, thereby changing and controlling the rotation direction and rotation speed of the hydraulic motor 43. A hydrostatic transmission configured to do so is provided. In FIG. 5, 47 is a high pressure relief valve that sets the oil pressure of the high pressure side circuit in the oil supply and discharge circuits 44 and 45;
Reference numerals 8 and 49 respectively indicate a pair of check valves that allow oil to flow only in the direction of the high pressure relief valve 47 from the oil supply and drainage circuits 44 and 45, and 50 operates from the oil tank 51 to the oil supply and drainage circuits 44 and 45. An oil replenishment circuit for replenishing oil, 52 a charge pump inserted into the oil replenishment circuit 50 and driven by the engine 11 to replenish hydraulic oil, 53 a low pressure relief valve for setting the oil pressure of the oil replenishment circuit 50, 54; 55 are each
These are a pair of check valves that allow oil to flow only from the oil supply circuit 50 to the oil supply and discharge circuits 44 and 45. As shown in FIG. 4, a hydraulic cylinder 56 for lever operation is provided with the end of the cylinder body pivotally supported on the machine body. 42a is connected to the shift lever 46 for operating the lever so that the shift lever 46 can be rotationally displaced by the expansion and contraction movement of the lever operating hydraulic cylinder 56. And the hydraulic cylinder 56
In order to selectively operate the lever operating hydraulic cylinder 56, an oil supply circuit 59 that guides the hydraulic oil set at the relief valve 58 from the oil tank 51 by a hydraulic pump 57 toward the lever operating hydraulic cylinder 56, and a lever operating hydraulic Oil supply and drainage circuits 60 and 61 connected to the extension oil chamber and contraction oil chamber of the cylinder 56, respectively.
An electromagnetic switching valve 62 as shown is provided between the two. This electromagnetic switching valve 62 connects the oil supply circuit 59 toward the oil tank 51 and blocks both oil supply and discharge circuits 60 and 61 ends.
a neutral position ^N where the motor stops at a certain extension/retraction position, and a speed increasing position I which is moved by the excitation of the solenoid 63. 51, the hydraulic cylinder 56 for lever operation is extended, and the shift lever 46 is rotated in the direction of arrow A so that the angle of the swash plate 42a of the hydraulic pump 42 is increased in the forward direction. The speed action position I and the deceleration action position are moved by the excitation of the solenoid 64, and the oil supply circuit 59 is connected to the oil supply and discharge circuit 61, and the oil supply and discharge circuit 60 is connected to the oil tank 51, and the lever is operated. 3 positions ^N and a deceleration action position in which the hydraulic cylinder 56 is shortened and the gear shift lever 46 is rotationally displaced in the direction opposite to the arrow A so that the angle of the swash plate 42a is decreased in the normal rotation direction of the hydraulic pump 42; ,,
It is equipped with In FIG. 4, reference numeral 65 denotes a lower limit speed regulation switch disposed within the rotation locus of the gear shift lever 46, and as described later, this lower limit speed regulation switch 65 controls the control shown in FIG. It is incorporated in the circuit, and is turned off by the lever 46 when the gear shift lever 46 rotationally displaces the pump swash plate 42a in the direction opposite to arrow A to a certain angle in the normal rotation direction of the hydraulic pump 42. The vehicle speed in the forward direction of the aircraft is regulated so that it does not fall below a certain speed. Also, in Figure 4, 66
is an electromagnetic short-circuit valve that selectively short-circuits both the oil supply and discharge circuits 60 and 61 between the electromagnetic switching valve 62 and the lever operating hydraulic cylinder 56, and this electromagnetic short-circuit valve 66 is normally operated by a spring. It assumes the illustrated non-short circuit position ^U under bias, and is moved to the short circuit position S by energizing the solenoid 67.
A power source 68 and a manual switch 69 are connected to the solenoid 67.
9, the electromagnetic short-circuit valve 66 is moved to the short-circuit position S. In the short-circuit position S of the electromagnetic short-circuit valve 66, the speed change lever 46 can be freely operated manually. In addition, the solenoids 63, 6 of the electromagnetic switching valve 62
Of course, it is also possible to configure the swash plate 42a to be magnetized by a manual switch so that the angle of the swash plate 42a can be changed by the hydraulic cylinder 56 even during manual operation. The vehicle speed of the illustrated combine harvester is determined by the control circuit shown in FIG. 6 according to the output of the handling barrel rotation speed detection circuit _C1 and the output of the grain loss detection circuit _C2 .
It is controlled by selectively energizing both the solenoids 63 and 64 of the lever operating hydraulic cylinder 56 described above. Before explaining the configuration of the above-mentioned control circuit for this purpose, the control logic will be explained first. As shown in FIG. It is divided into three zones: an excessive rotation speed zone H, which has a higher rotation speed, and an under-rotation speed zone L, which has a lower rotation speed than the proper rotation speed zone M, and the upper and lower limits of the appropriate rotation speed zone M are set respectively. , a voltage corresponding to the output voltage signal Vrev of the handling cylinder rotation speed detection circuit _C1 , which is the appropriate zone upper limit voltage Vomax and the appropriate zone lower limit voltage Vomin, as shown in FIG. 7a. In addition, as shown in Fig. 7b, the Glen loss is divided into two zones: an excessive loss zone H that is greater than a certain amount of loss and an underloss zone L that is less than the certain amount of loss.
The above constant loss amount is set to be divided into zones, and the above output voltage signal of the Glenn loss detection circuit _C2
The voltage corresponds to Vloss, which is the loss reference voltage Vdef as shown in FIG. 7b. The control logic is assembled to control vehicle speed increase/decrease in six control areas, as shown in Table 1 below.

【table】

[Table] To explain the specific circuit configuration with reference to Fig. 6, the output voltage signal Vrev of the handling cylinder rotation speed detection circuit _C1
The first comparator 70 is supplied to the positive input terminal, and the second comparator 70 is supplied to the negative input terminal.
Comparators 71 are provided respectively. Then, the above-mentioned appropriate zone upper limit voltage Vomax is introduced into the negative input terminal of the first comparator 70 by appropriately lowering and adjusting the power supply voltage Vcc with the first variable resistor 72. The above-described appropriate zone lower limit voltage Vomin is introduced into the plus side input terminal of the comparator 71 by further lowering the upper limit voltage Vomax with a second variable resistor 73 and adjusting it appropriately. As described above, the first comparator 70 outputs the excessive rotation speed signal voltage Vh when the output voltage Vrev of the handling cylinder rotation speed detection circuit _C1 is higher than the appropriate zone upper limit voltage Vomax (Vrev>Vomax), Conversely, the second comparator 71 outputs the under-rotation speed signal voltage V1 when the output voltage Vrev of the handling cylinder rotation speed detection circuit _C1 is lower than the appropriate zone lower limit voltage Vomin (Verv<Vomin). , it's summery. In addition, a third comparator 74 is supplied with the output voltage signal Vloss of the Glen loss detection circuit _C2 to its positive input terminal.
is provided, and this third comparator 7
The power supply voltage Vcc is connected to the negative input terminal of 4.
The above-mentioned loss reference voltage Vdef is introduced by adjusting the voltage appropriately with the variable resistor 75.
Therefore, this third comparator 74 operates when the output voltage Vloss of the Glen loss detection circuit _C2 is larger than the loss reference voltage Vdef (Vloss>Vdef).
The loss excessive signal voltage Vg is output. Similarly, as shown in FIG. 6, a NAND circuit 77 is provided, and the first comparator 70 is directly connected to the input terminal of this NAND circuit 77.
Further, a third comparator 74 is connected to each other via an inverter 78. Furthermore, the first pulse generator 79 and the second pulse generator 80,
A first pulse generator 7 is provided, among which a first pulse generator 7
A NAND circuit 77 is connected to the input terminal of 9 via an inverter 81. Further, a second comparator 71 is connected to the input terminal of the second pulse generator 80.
are connected directly and the third comparator 74 is connected through a diode 82, respectively. As described above, the first pulse generator 79 and the second pulse generator 80 are connected to the comparators 70, 71, 74.
Depending on the presence or absence of the output voltages Vh, Vl, and Vg, the following second
It will be operated as shown in the table.

[Table] Furthermore, as shown in FIG. 6, the solenoids 63 and 64 of the electromagnetic switching valve 56 described above are connected in parallel with surge absorption diodes 84 and 85.
Moreover, one end is connected to a power supply terminal, the other end is grounded, and inserted into the control circuit. The grounding side of solenoids 63 and 64 has an emitter grounding.
A switching circuit including NPN transistors 86 and 87 is provided.
87 base with first and second pulse generators 7
9 and 80 are connected via resistors 88 and 89, respectively, and transistors 86 and 8
Both of the switching circuits described above are completed by grounding the base of 7 through pull-down resistors 90 and 91. Based on the above, each pulse generator 7
When voltage pulses are not output from transistors 9 and 80, the resistance value between the collector and emitter of each transistor 86 and 87 is close to infinity, and no current flows between them. When input from 79, 80 to the ground of each transistor 86, 87, the transistor 86, 87
The resistance value between the collector and emitter of the solenoid 63 and emitter is extremely reduced, and a current flows between the solenoids 63 and 6.
The current flowing through 4 causes each solenoid 6 to
3 and 64 are selectively excited. As shown in FIG. 6, the lower speed limit switch 65 described above is inserted into a circuit that connects the solenoid 64 to a power terminal. solenoid 64
is for displacing the electromagnetic switching valve 62 to the deceleration action position as described above. Therefore, when the lower limit speed regulation switch 65 is turned off by the speed change lever 46 as described above, the solenoid 64 is not energized even if the second pulse generator 80 is operating, and therefore the electromagnetic Since the switching valve 62 does not take the deceleration action position,
The lower limit speed in the forward direction of the aircraft is regulated. Note that an NPN transistor 92 with a grounded emitter is connected to the output terminal of the first comparator 70 as shown in FIG. 6, and the output terminal of the second comparator 71 is connected to the base of this transistor 92. , constitutes a switching circuit, and as long as the second comparator 71 outputs the underspeed signal voltage V1, even if the first comparator 70 unexpectedly outputs the excessive speed signal voltage Vh for some reason, the corresponding The voltage Vh is designed to be reduced by grounding. That is, the second comparator 71 functions to compare the rotation speed of the handling cylinder with a set lower limit value, and to energize the solenoid 64 for vehicle speed reduction using the underspeed rotation signal voltage V1. As mentioned above, priority is given to the deceleration side. The vehicle speed control device according to the present invention, shown in FIGS. 1-7, is constructed as described above, and operates as follows during harvesting work using a combine harvester. In other words, it is clear that each control range in Table 1 and each case in Table 2 correspond to each other, and it is clear that each control range in Table 1 and each case in Table ₂ correspond to each other. As shown in Table 2, according to the detected value of the rotational speed of the handling cylinder and the grain loss value obtained by the grain loss detector 34 or the grain loss detection circuit _C2 ,
First pulse generator 79 and second pulse generator 8
0 is selectively activated, thereby causing the fourth
A solenoid 63 for moving the electromagnetic switching valve 62 shown in the figure to the speed increasing position and a solenoid 64 for moving it to the decelerating position are selectively energized, and as shown in Table 1, each control area is Alternatively, the vehicle speed is reduced or increased in each case. As is clear from Table 1, if the grain loss is excessive, the vehicle speed control logic for each control region or case will act on the threshing section 8 regardless of the rotation speed of the handling cylinder 13. Regardless of the magnitude of the load, the vehicle speed is reduced to improve the sorting accuracy at the sorting degree of 12, and the sorting degree of the sorting section 12 is within the appropriate range and the rotation speed of the handling cylinder 13 is excessive. The assembly is such that when the threshing section 8 receives only a sufficient load, the vehicle speed is increased to improve work efficiency. Therefore,
According to the illustrated vehicle speed control device, during harvesting work using a combine harvester, work with improved work accuracy and work efficiency can be carried out under automatic control. In the above embodiment, the grain loss detector 34 that detects the grain loss ratio in the waste is provided as a sorting degree detector that detects the degree of grain removal sorting. 8th, 9th
The figure shows another embodiment in which a sorting degree detector 34A is provided as such a sorting degree detector, which directly detects the sorting degree from the straw waste ratio in the sorted grain culms. be. That is, in the threshing plate 8 according to this other embodiment, as shown in FIG. 8, the upper stroke rack 19 in the threshing section 8 shown in FIG. Unlike the illustrated dust exhaust fan 21, it is disposed at the rear and upper side of the stroller rack 19, and further,
The No. 3 dust exhaust port corresponding to the No. 3 dust exhaust port 25 shown in FIG. The above-mentioned sorting degree detector 34A is divided into an upper dust exhaust port 96 for discharging dust from the end of the stroke rack 19, and a lower dust exhaust port 97 for mainly discharging dust from the end of the stroke rack 19. , a grain flow plate 98 provided below the grain sieve 18 and inclined in the direction of the first mouth 22, which guides grains leaking through the grain sieve 18 in the direction of the first mouth 22.
It is provided on 8. The bandpass filter 35A attached to the selectivity detector 34A is different from the above-mentioned bandpass filter 35 in that, among the voltage pulses P ₁ and P ₂ from the main body of the detector 34A, the voltage pulse P corresponding to straw waste is ₂ is filtered, and the voltage pulse _P1 corresponding to the grain is cut off and not transmitted to the secondary side. As a result, the sorting degree detector 34A directly detects the sorting degree by detecting the straw waste ratio in the grains after sorting. Therefore, the output signal of the bandpass filter 35A can be used together with the output signal of the handling drum rotation speed detector 28 in the same manner as in the previous embodiment to control the operation of the threshing section. Note that if the selection sensitivity is low when using only one selection degree detector 34A, a plurality of detectors 34A may be provided.
The outputs can be added together using an adder and used for control purposes. As is clear from the above description, the vehicle speed control device of the combine harvester of the present invention has the following effects. In this control, vehicle speed deceleration control based on the degree of sorting is first performed preferentially so that there is no loss in the harvesting work of the combine harvester. Therefore, it is possible to reliably prevent sorting loss from occurring. Furthermore, when the degree of sorting is good, the speed is increased as much as the load allows, allowing highly efficient work.

[Brief explanation of drawings]

FIG. 1 is a schematic side view of a combine equipped with an embodiment of the present invention, FIG. 2 is a schematic vertical side view of the main parts of the combine, and FIG.
FIG. 4 is a schematic diagram and hydraulic circuit diagram showing the control mechanism and hydraulic circuit in the same embodiment; FIG. 5 is a hydraulic circuit diagram showing the traveling drive section of the combine harvester; FIG. 6 is a block diagram and an electric circuit diagram showing an electric control circuit in the same embodiment, and FIGS. 7a and 7b are explanatory diagrams showing control range settings in the same embodiment, respectively. FIG. 8 is a schematic vertical sectional side view of the main part of a combine equipped with another embodiment of the present invention, and FIG.
It is a schematic diagram for explaining the action of the member. DESCRIPTION OF SYMBOLS 1... Crawler, 8... Threshing section, 11... Engine, 12... Sorting section, 13... Handling cylinder, 13a...
...Handling trunk shaft, 20...Kingen, 21...Dust exhaust fan,
25... No. 3 dust exhaust port, 28... Handling cylinder rotation speed detector, 29... Rotor, 30... Magnet, 31
...Reed switch, 32...Integrator, 34...
Glen loss detector, 35... band pass filter, 37... monomulti, 38... integrator, 40
... Drive wheel, 41 ... Mission case, 42 ...
...Hydraulic pump, 42a...Swash plate, 43...Hydraulic motor, 44, 45...Oil supply/drainage circuit, 46...Speed lever, 56...Hydraulic cylinder for lever insertion, 6
2... Solenoid switching valve, 63, 64... Solenoid,
70, 71, 74... Comparator, 76, 77
...NAND circuit, 78...Inverder, 79,
80...Pulse generator, 81...Inverter, 8
2...Diode, 83...Inverter, 86,
87... Transistor, 34A... Sorting degree detector, 95... Dust exhaust fan, 98... Grain flow board, 35
A...Band pass filter.

Claims (1)

[Claims] 1 A threshing load detector that detects the load acting on the threshing section and a sorting degree detector that detects the degree of threshing sorting by the sorting section are provided, and when the sorting degree detection signal is in the excessive loss zone, the threshing load detector is installed. A combine harvester characterized by having means for preferentially decelerating regardless of the signal, and means for increasing speed only when the sorting degree detection signal is in the underloss zone and the threshing load detection signal is in the light load zone. Vehicle speed control device.