JPH09103169A - Vehicle speed controller in harvester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle speed controller in a harvester capable of previously preventing a trouble without inducing an overload state of an engine even increasing of a load by installing a means instructing an action of a controlling mode keeping a rotation number of an engine at a rated rotation number to an engine rotation number controlling part. SOLUTION: This vehicle speed controller in a harvester is constructed to be switched to the first controlling mode in which a rotation number controlling part of an engine acts to keep a detecting value of a rotation number of the engine to a prescribed rotation number within a range below a rated output E1 (first output) of the engine relating to the characteristic of the engine and to the second controlling mode in which the output of the engine acts to keep the detecting value of the rotation number of the engine to a prescribed rotating number within a range below the maximum output E0 (second output) above the first output. The vehicle speed controller also has a working state detecting means detecting the working state of the working part and a means stopping an automatic change and instructing to the engine rotation number controller at an action in the first controlling mode in a case of detecting a working state other than a harvesting work by the working state detecting means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle speed control device for a harvester that automatically adjusts a traveling speed to a slow speed according to a load increase / decrease in a working unit such as a threshing unit and a mowing unit.

[0002]

2. Description of the Related Art In a harvester that cuts grains while traveling on a field and threshes and sorts the grains to extract fine grains, the load on the working unit such as the mowing unit and the threshing unit is the amount of treated grains. The amount of processed grain mainly depends on the traveling speed. Therefore, the load state in the working unit is maintained at a state close to the maximum allowable load, and a vehicle speed control device that automatically adjusts the traveling speed based on the detection result of the load in the working unit to obtain the highest harvesting efficiency is provided. There is a harvester.

As such a vehicle speed control device, there are inventions of Japanese Patent Application Nos. 61-249848 and 61-304918 by the present applicant. While these are equipped with an engine speed control unit for controlling the engine that drives the traveling unit and working unit of the harvester at a constant speed at a constant speed (isochronous control),
The load on the working unit is detected as the load of the engine that drives the work unit, for example, by the position of the fuel rack of the fuel injection pump, and the transmission travels so that the traveling speed becomes slow according to the magnitude of the detected load. The configuration is such that the speed adjustment position can be changed. In this vehicle speed control device, the engine speed is maintained constant regardless of the load, and the traveling speed and the traveling speed adjustment position of the transmission uniquely correspond to each other. The load can be predicted, and the harvesting work can be performed in a state where the output of the engine is maintained in the vicinity of the rated output, and high working efficiency can be realized.

FIG. 6 shows an output characteristic curve of an engine which is isochronously controlled by the operation of the engine speed control section in comparison with an output characteristic curve of the engine during normal operation. As shown by the solid line in this figure, when the engine speed control unit is operating, the engine is maintained at its rated speed N ₀ in the range from 0 to the maximum output E _0. The Japanese Patent Application Sho 61-
In the vehicle speed control devices of No. 249848 and Japanese Patent Application No. 61-304918, the maximum output E ₀ is slightly higher than the rated speed N ₀ on the output characteristic curve during normal operation shown by the broken line in the figure. It is set so as to be slightly higher than the peak value (rated output) E _{1 of the} shaft output generated at a low rotation speed N ₁ . This is due to the occurrence of clogging in the threshing part during the harvesting work in which the vehicle speed control is performed while maintaining the state in which the load equivalent to 85% to 90% of the rated output E ₁ is applied to the engine. This is because when an excessive load that exceeds the rated output E ₁ is momentarily applied, it can be accepted without lowering the rotation speed.

[0005]

In the harvester equipped with the vehicle speed control device as described above, the vehicle speed is manually decelerated or increased when, for example, reaping one stroke and shifting to the next stroke. However, if the operation of the engine speed control unit is stopped at this time, the engine speed will suddenly decrease or increase to the speed corresponding to the accelerator position at that time, and the handling cylinder Also, due to a sudden change in the rotation speed of the conveying screw, there is a possibility that a problem such as clogging of untreated grain occurs in the threshing section. On the other hand, when the vehicle speed is decelerated or increased by manual operation of the shift lever that changes the traveling speed adjustment position of the transmission without stopping the operation of the engine speed control unit,
Since the engine speed does not change, the risk of clogging in the threshing section is eliminated, but as a result of speedup in this way, the load between the maximum output E ₁ and the rated output E ₁ is exceeded. May add to the engine. However, even in this case, since the engine speed is kept at the rated speed N ₀ by the operation of the engine speed control unit, the operator does not notice that an excessive load is applied to the engine, and As a result of continuing the operating state and forcing the engine to operate for a long time in an overloaded state, there is a possibility that the engine may break down or the life of the engine may be shortened without noticing it.

[0006] In addition, even when the harvester is used as a thresher, the engine speed control unit is operated by manually feeding the harvested grain culm to the thresher without running the harvester. , It is desirable to do this by keeping the engine speed constant, but if a large amount of harvested grain culms are sent all at once to the threshing section and the amount of fed grain culms becomes excessive, the engine In addition, there is a possibility that the driver may be forced to operate for a long time under an overloaded condition.

The present invention has been made in view of the above circumstances, and when the shifting operation is manually performed in the next mowing process while using a harvester as a stationary thresher, the engine is overloaded. An object of the present invention is to provide a vehicle speed control device for a harvester, which is capable of performing these operations in a state of maintaining a constant number of rotations without forcing a long-time operation under load.

[0008]

A vehicle speed control device for a harvester according to the present invention is an engine speed control that operates to maintain a detected value of the speed of an engine that drives a working unit and a traveling unit at a predetermined speed. Vehicle speed control device for controlling the traveling speed of a harvester equipped with a section by automatically changing the traveling speed adjustment position of a transmission that can be manually changed, and controlling to properly maintain the load of the working section. In the first engine speed control section, the engine speed control section operates to maintain the detected value of the engine speed at a predetermined speed within a range in which the engine output is equal to or lower than a first output related to engine characteristics. The control mode is switched to a second control mode in which the engine output operates to maintain the detected value of the engine speed at the predetermined speed within a range where the engine output exceeds the first output and is equal to or less than the second output. Configured as A work state detecting means for detecting a work state of the working part, and when the work state detecting means detects a work state other than the harvesting work, suspends the automatic change and causes the engine speed control part to , Means for instructing an operation in the first control mode.

In the present invention, when the machine is not in a normal harvesting work state such as when it is used as a stationary thresher, or when it is recognized based on the detection result of each of the detecting means, the traveling speed setting position is determined. The automatic change is suspended and the engine speed control unit is instructed to operate in the first control mode in an output range that does not exceed the rated output of the engine.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. FIG. 1 is a schematic right sectional view of a normal type harvester equipped with a vehicle speed control device for a harvester according to the present invention (hereinafter referred to as the device of the present invention), and FIG. 2 is a plan view.

In the figure, 1 is a machine body mounted on the upper side of a pair of left and right traveling crawlers 2, 2 (only one side is shown), and a threshing section 3 is installed on the upper left side of the machine body 1 over the entire length in the front-rear direction. The driver's seat DS, the grain tank 7 and the engine 8 are installed in this order from the front on the upper right side, and the cutting unit 4 is mounted on the front side of the machine body 1 so as to be vertically movable. The traveling crawlers 2 and 2 are driven simultaneously or separately by the driving force of the engine 8 transmitted through a main clutch (not shown), a hydrostatic continuously variable transmission, and left and right side clutches. , In front of Aircraft 1,
Reverse or turn.

As the machine body 1 moves forward,
A grain culm is introduced from between a pair of left and right dividers 41, 41 provided in the front part thereof, and the grain culm is rotated by a take-up reel 42 which is axially supported in the upper part of the mowing unit 4 with the axial direction as the horizontal direction. While being pulled backward, it is cut by the cutting blade 43 that is arranged below the cutting unit 4 and repeatedly moves in the left-right direction. On the upper side of the platform 45 extending to the rear side of the cutting blade 43, a horizontal conveying auger 44 having a columnar shape and forming a spiral conveying plate 44a on its peripheral surface is provided with a shaft length direction as a left-right direction. Is supported,
The grain cut by the cutting blade 43 is laterally transported on the platform 45 in accordance with the rotation of the lateral transport auger 44 by the action of the transport plate 44a, and is transferred to the rear part of the cutting part 4 and the front part of the threshing part 3. In the opening at the front end of the feeder house 5 that communicates with the feeder house 5, the chain conveyor 50 takes over the sheet and conveys it upward and rearward in a state of being sandwiched between the conveyor 50 and the bottom plate of the feeder house 5. It is adapted to be introduced into the handling chamber 30 of the threshing unit 3 through the rear end opening.

On the bottom plate of the feeder house 5, a plurality of grain sensors 51, 51, for detecting the presence / absence of grains in the feeder house 5, that is, the presence / absence of grains fed to the threshing section 3, are arranged side by side in the left / right direction. I am doing it. As the grain sensors 51, 51 ..., for example, the pressure receiving surface is installed facing the inside of the feeder house 5,
When a grain conveyed by the chain conveyor 50 in the feeder house 5 comes into contact with the pressure receiving surface, it is possible to use a piezoelectric conversion element which emits a signal of a level corresponding to the pressure receiving from the grain.

In the handling chamber 30, there is provided a screw handling cylinder 31, which is formed by spirally forming a double pitch screw and a large number of handling teeth on the circumferential surface of a cylinder, and is axially supported with its axial direction in the longitudinal direction. Therefore, the grain introduced into the handling chamber 30 is threshed by the action of the screw while being transported backward by the action of the screw according to the rotation of the screw handling cylinder 31. After threshing processing, the grated food passes through the receiving net 33 stretched on the lower side of the handling cylinder 31, and falls on the rocking and sorting device 32 arranged under the threshing unit 3, Specific gravity sorting is performed by the synergistic action of the swing of the device 32 and the sorting wind that is blown by the Karato device 34 installed on the front side of the lowermost part of the threshing unit 3 and is blown as shown by the white arrow in FIG. It

That is, the fine grains having a relatively high specific gravity in the grated product are the No. 1 gutter 35 provided at the lower part on the upstream side of the sorting wind.
It drops to the upper side and is conveyed in the right direction, and is conveyed upward in the fried-grain barrel 35a which is connected to the right end thereof, and is stored in the grain tank 7. In addition, the second thing such as ear cutting grain, spike sticking grain,
Dropped onto the No. 2 gutter 36, which is located on the downstream side of the selection wind from the No. 1 gutter 35, and conveyed rightward.
The inside of the number-returning cylinder 36a is conveyed to the front upper side, is reintroduced into the foremost part of the handling chamber 30, and is reprocessed. Furthermore, the 3rd items such as straw and dust contained in the grated food are blown backward by the sorting wind and are discharged from the rear end of the screw handling cylinder 31 along with the end of the threshing unit 3. It is discharged onto the field from the No. 3 opening 37 that opens downward in the area.

The traveling speed of the harvester that performs the cutting, threshing, and sorting processing as described above is determined by the rotation speed of the engine 8 and the traveling speed adjustment position of the continuously variable transmission. Shift lever 60 for setting this traveling speed adjustment position
Is disposed on the operation column 6 provided on the left side of the driver's seat DS, and an operator seated in the driver's seat DS rotates the lever 60 back and forth to adjust the traveling speed adjusting position. It can be set steplessly. A shift motor 17 for rotating the lever 60 is provided at a base end pivot portion of the gear shift lever 60.
(See FIG. 3) is mounted, and the traveling speed adjustment position is changed to the high-speed traveling side or the low-speed traveling side according to the forward or reverse rotation of the shift motor 17. Further, in the vicinity of the pivot of the shift lever 60, a neutral switch 14 and a reverse switch 15 which are turned on when the traveling speed adjusting position is in the neutral position and in the reverse position, respectively.
(See FIG. 3). On the operation column 6, in addition to the shift lever 60, an accelerator lever 61 for manually setting the operating state of the engine 8, and an automatic switch 11 for instructing the device of the present invention to start operation (see FIG. 3).
Various levers and switches are provided.

FIG. 3 is a block diagram showing the configuration of the device of the present invention, in which 10 is a vehicle speed control unit and 20 is an engine speed control unit. When the detection result of the rotation speed of the engine 8 is different from the rated rotation speed N ₀ , the engine rotation speed control unit 20 moves a fuel rack (hereinafter referred to as a rack) of a fuel injection pump (not shown) to move to the engine 8. By controlling the fuel supply amount, so-called isochronous control is performed to operate the engine 8 so as to match the engine speed with the rated engine speed N _0. The output signals of the rack position sensor 21 and the engine rotation sensor 22 for detecting The rack position sensor 21 is, for example, a differential transformer that is coaxially mounted on the rack and outputs a voltage corresponding to the moving position of the rack. The engine rotation sensor 22 is mounted on the output shaft of the engine 8, for example. A rotary encoder that outputs a number of pulse signals corresponding to the rotation speed of the output shaft is used.

To the input side of the engine speed control unit 20, an operation start command signal is given from the output port b ₄ of the vehicle speed control unit 10 and a mode command signal is also given from the output port b ₅ to the input side, as will be described later. There is. On the other hand, the output of the engine speed control unit 20 is given to a rack actuator 23 for moving the rack. Rack actuator
Reference numeral 23 denotes, for example, a linear solenoid that linearly moves according to an output signal of the engine speed control unit 20 and is coaxially mounted on the rack.

The engine speed control unit 20 controls the engine speed.
The current rotation of the engine 8 according to the input signal from the sensor 22
Recognize the number, this is the rated speed N₀Showed a different value from
In this case, the detected rotation speed and the rack position sensor 21
Depending on the current rack position recognized by the input signal,
Based on the arithmetic expression stored in advance, the rated rotational speed N ₀
The target rack position where the rack should be located to obtain
Then, a signal corresponding to the calculation result is output. Laqua
The actuator 23 moves the rack to the target according to this signal.
It operates to move it to the rack position,
As a result of adjusting the fuel supply amount, the engine 8
Rated speed N₀Is maintained.

Further, the engine speed control unit 20 has a first control mode in which the above-mentioned operation is performed in the output range until the output of the engine 8 reaches the rated output E ₁ (first output), and the rated output. It has a second control mode in which the above-described operation is performed in an output range up to a predetermined maximum output E ₀ (second output) which exceeds E ₁ by about 10%. FIG. 4 shows the engine speed control unit 20 in these first and second control modes.
Is an output characteristic curve of the engine 8 in the case where is operated, in the figure, the alternate long and short dash line shows the first control mode, and the solid line shows the second control mode. Both control modes are selected according to the mode command signal input from the output port b ₅ of the vehicle speed control unit 10. When the signal is at a low level, the operation in the first control mode is When it is at the high level, the operation in the second control mode is selected.

On the other hand, the vehicle speed control unit 10
Running of the continuously variable transmission based on the current load detection result
Change the speed adjustment position to reduce the load on the engine 8
Load E ₁Within the preset range of about 85 to 90% of
In order to maintain it, the running speed is automatically adjusted.
Input port a₁The automatic switch 11 is connected to
The switch 11 is turned on by a worker sitting in the driver's seat DS.
Input port a when turned on₁Turns to high level
I will.

The input ports a _{2 to} a ₄ are provided with a threshing unit 3
Also, means for detecting the current work state of the reaper 4 is connected. That is, the threshing switch 12 that is turned on when the threshing clutch that engages and disengages the power to the threshing unit 3 is engaged with the input port a ₂ and the input port a ₃ , and the disengagement of the power to the reaping unit 4. The mowing switch 13 that is turned on when the mowing clutch for performing the operation is connected to the threshing switch 11, and the input port a ₂ is turned on when the threshing switch 11 is turned on, and the input port a ₃ is turned on when the mowing switch 12 is turned on. The input port a ₄ is connected to the comparator.
It is connected to the output side of 51a and turns to a high level according to the high level output of the comparator 51a. The + input of the comparator 51a is a voltage obtained by superimposing the outputs of the grain sensors 51, 51 ... Arranged in parallel on the bottom plate of the feeder house 5, and its-input is a predetermined voltage set by the voltage divider 51b. It is a voltage. Therefore, input port a
₄ indicates that when the conveyed grain comes into contact with the pressure receiving surfaces of the grain sensors 51, 51 ... And the output voltage thereof becomes higher than the voltage set by the voltage divider 51b, that is, the grain is fed to the threshing unit 3. If it is, it goes high.

Therefore, the vehicle speed control unit 10 controls the input port a
_{When 2} , a ₃ and a ₄ are all at the high level, it is recognized that the normal harvesting work is in progress, and further, the automatic switch 11
The vehicle speed control operation described later is performed only when the input port a ₁ is at a high level due to turning on.

Means for detecting the current traveling state of the harvester are connected to the input ports a _{5 to} a ₇ of the vehicle speed control unit 10, respectively. That is, the neutral switch 14 and the reverse switch 15 are connected to the input port a ₅ and the input port a ₆ , respectively, so that the input ports a ₅ and a ₆ are turned to a high level when these switches are turned on. The vehicle speed control unit 10 recognizes that the vehicle is moving forward, backward, or stopped based on the levels of the input ports a ₅ and a ₆ . The output signal of the vehicle speed sensor 16 for detecting the traveling speed is given to the input port a ₇ . Vehicle speed sensor 16
For example, a rotation speed detector that detects the teeth of the gear fixed to the axle of the traveling crawler 2 with an electromagnetic pickup and outputs a pulse signal that is an integral multiple of the rotation speed of the axle is used. The vehicle speed control unit 10 counts for a predetermined time, calculates the vehicle speed from the counting result, and recognizes it.

Further, at the input port a ₈ of the vehicle speed control unit 10,
An output signal of the rack position sensor 21 is given,
The vehicle speed control unit 10 recognizes the current rack position based on this signal. As will be described later, when the vehicle speed control unit 10 is performing its control operation, the rotation speed of the engine 8 is always maintained at the rated rotation speed N ₀ by the operation of the engine rotation speed control unit 20, so that the rack is operated. The position is the output of the engine 8,
In other words, in response to the load applied to the engine 8, the vehicle speed control unit 10 can recognize the current load state of the engine 8 by the input signal to the input port a ₈ .

On the other hand, the output ports b ₁ and b _{2 of the} vehicle speed control unit 10
Is connected to the shift motor 17 for rotating the shift lever 60 via a drive circuit (not shown), and the output port b
_The shift motor 17 rotates normally (or reversely) in response to the high level output of ₁ (or the output port b ₂ ), and the traveling speed adjustment position is changed to the high speed (or low speed) traveling side, and the traveling speed of the harvester increases. It is designed to be speeded (or decelerated). Further, the output port b ₃ is connected to a vehicle speed lamp 18 for informing a worker that the vehicle speed control unit 10 is in an operating state,
The lamp 18 is lit according to the high level output of the output port b ₃ .

Further, the output ports b ₄ and b ₅ are respectively connected to the input side of the engine speed control unit 20, and the engine speed control unit 20 responds to the high level output of the output port b ₄ . As described above, the control operation is performed in the control mode corresponding to the level of the output port b ₅ .

In the vehicle speed control unit 10, the relation between the vehicle speed of the harvester and the load applied to the engine 8 when the engine 8 is at the rated speed N ₀ is calculated in the working units such as the threshing unit 3 and the cutting unit 4. A plurality of load characteristic curves obtained by actually performing the harvesting work under various different load states are stored in advance in the form of a numerical table or an approximate expression. And the vehicle speed control unit 10
Recognizes the current vehicle speed from the output signal of the vehicle speed sensor 16 input to the input port a ₇ , and recognizes the current load on the engine 8 from the output signal of the rack position sensor 21 input to the input port a _8. However, after selecting one of the plurality of load characteristic curves corresponding to these recognition results, the load on the engine 8 is about 85 to 90% of the rated output E ₁ on the selected load characteristic curve. Calculate the target vehicle speed within the specified range, compare this target vehicle speed with the current vehicle speed, and the target vehicle speed is higher (or lower)
In this case, the current vehicle speed is recognized from the signal input to the input port a ₇ in order to increase (or decelerate) the vehicle speed, and the output port b ₁ ( Alternatively, the same b ₂ ) is set to a high level, and the shift motor 17 is normally rotated (or reversely rotated). By the operation of the vehicle speed control unit 10, the engine 8 during the harvesting work is always operated under an appropriate load condition that is slightly smaller than the rated output E ₁ , and the harvesting work with high efficiency is realized. To be done.

The vehicle speed control unit 10 configured as described above performs the operation shown in the flowchart of FIG. 5 according to the working state of the working unit and the traveling state of the harvester. The vehicle speed control unit 10 first checks the on / off state of the automatic switch 11 according to the level of the input port a ₁ ,
When 11 is off, the output port b _{3 is set} to the low level, the vehicle speed lamp 18 is turned off, the output port b ₄ is maintained at the low level, and the automatic switch 11 is on standby. In this case, the engine speed control unit 20
Does not perform the control operation, the operator seated in the driver's seat DS can operate the shift lever 60 and the accelerator lever 61 to appropriately set the traveling speed and run the harvester.

On the other hand, when the automatic switch 11 is turned on, the vehicle speed control unit 10 sets the output port b ₃ to the high level and turns on the vehicle speed lamp 18 to notify the operator that the vehicle speed control unit 10 is in the operating state. Output port b
_{4 is set} to a high level to instruct the engine speed control unit 20 to start operation. After this, the engine 8 is operated at the rated output regardless of the rotational position of the accelerator lever 61 by the operation of the engine speed control unit 20 according to the first or second control mode selected as described later. Output range up to E ₁ or maximum output E ₀ approximately 10% more than rated output E ₁
In the output range up to, it is rotated at a constant speed at the rated speed N ₀ .

Next, the vehicle speed control unit 10 controls the input port a
_Two~ A_FourThe working state in the working part by the level of
You. And input port a_Two, A_ThreeIs at a high level,
It is detected that the threshing unit 3 and the mowing unit 4 are operating.
And input port a_FourIs at a high level and grain
Feeding of harvested cereal to threshing unit 3 is detected by sensors 51, 51 ...
If so, it is considered normal harvesting conditions.
And proceed to the next step, while selecting one of the above conditions.
If one is not satisfied, that is, input port a _Two~ A_Four
Is low level, the output port b
_FiveTo the low level, and the first
After the operation in the control mode is commanded, the vehicle speed control
Return to the first stage of the flowchart without performing any operation.

When the above conditions are satisfied, the vehicle speed control unit 10 next checks the traveling state of the harvester according to the levels of the input ports a ₅ and a ₆ . When the input port a ₅ or the input port a ₆ is at the high level and it is recognized that the harvester is stopped or moving backward, the output port b ₅ is set at the low level and the engine speed control unit is set. After instructing 20 to operate in the first control mode, the process returns to the first stage of the flowchart without performing the vehicle speed control operation.

On the contrary, when both output ports a ₅ and a ₆ are at the low level and it is recognized that the harvester is moving forward, then the vehicle speed control unit 10 causes the shift lever to move during the aforementioned vehicle speed control operation. The setting state of the flag F which is set when 60 is manually operated is checked, and when it is set, the output port b ₅ is set to the low level and the engine speed control unit 20 is set in the first control mode. After instructing the operation of, the process returns to the first stage of the flowchart without performing the vehicle speed control operation. The flag is set, for example, when the vehicle speed detected by the vehicle speed sensor 16 does not match the target vehicle speed after the drive signal is output to the shift motor 17 to realize the target vehicle speed during the vehicle speed control operation. It is designed to be automatically reset after a lapse of time.

Then, the flag F is reset.
In this case, the vehicle speed control unit 10_FiveThe high level
In the second control mode, the engine speed control unit 20
The operation of the vehicle speed sensor 16 and rack position
Input port a from sensor 21 ₇And input port a₈Husband
We take in the signals that are input each time, and based on these,
Perform speed control operation.

Due to this operation of the vehicle speed control unit 10, when the gear shift lever 60 is not manually operated during the normal harvesting work, the engine speed control unit 20 is controlled by the second control mode. The engine 8 keeps the rotation speed constant until the load applied to the engine 8 reaches E ₀ , which is larger than the rated output E ₁ , and the threshing unit 3 or the cutting unit 4 is operated during the harvesting work. The rotational speed of the engine 8 does not change even if an excessive load is instantaneously applied to the engine.

On the other hand, when the gear shift lever 60 is manually operated in the case where the cutting of one stroke is completed and the process shifts to the next stroke, the flag F is set, so that the engine speed control unit 20 causes the engine speed control unit 20 to change to the first stroke. Since it operates in the control mode No. 1, the output of the engine 8 does not exceed its rated output E ₁ . The flag F is reset after a lapse of a predetermined time, but at that time, the feeding of the grain to the threshing section 3 has already been stopped, and the grain sensors 51, 51 ... Are not detecting the fed grain, Since the input port a ₄ is at the low level, the engine speed control unit 20 continues the first control mode, the harvesting of the next stroke is started, and the grain sensors 51, 51
... shifts to the second control mode when the fed grain is detected again.

In the embodiment, the case where the device of the present invention is applied to an ordinary type harvester equipped with a reel has been described, but it goes without saying that the device of the present invention is also applicable to a self-removing type harvester. When using a self-throwing harvester equipped with the device of the present invention as a stationary thresher without running, the shift lever 60 is in the neutral position, the neutral switch 14 is off, and the input port of the vehicle speed control unit 10 is Since a ₅ is at the low level, the engine speed control unit 20 operates in the first control mode, and the engine 8 does not generate the output exceeding the rated output E ₁ .

[0038]

According to the present invention, when the harvesting work is being performed by switching and controlling the first and second control modes by the engine speed control unit, or when the harvester is used as a stationary thresher. Regardless of the load, the engine will not be overloaded even if the load increases, and it is possible to prevent the life of the engine from decreasing and the occurrence of failure.

[Brief description of the drawings]

FIG. 1 is a right side sectional view of a conventional harvester equipped with the device of the present invention.

FIG. 2 is a plan view of a conventional harvester equipped with the device of the present invention.

FIG. 3 is a block diagram showing a configuration of the device of the present invention.

FIG. 4 is a graph showing the output characteristics of the engine when the engine speed control unit operates in the first and second control modes.

FIG. 5 is a flowchart for explaining the operation of the device of the present invention.

FIG. 6 is a graph showing an output characteristic of an engine under isochronous control and an output characteristic of an engine during normal operation.

[Explanation of symbols]

 3 Threshing Unit 4 Mowing Unit 8 Engine 10 Vehicle Speed Control Unit 11 Automatic Switch 12 Threshing Switch 13 Mowing Switch 14 Neutral Switch 15 Reverse Switch 17 Shift Motor 20 Engine Speed Control Unit 51 Grain Sensor 60 Shift Lever

Claims (1)

[Claims] 1. A shift speed capable of manually changing the traveling speed of a harvester equipped with an engine rotation speed control unit that operates to maintain a detected value of the rotation speed of an engine that drives a working unit and a traveling unit at a predetermined rotation speed. In the vehicle speed control device of the harvester, which adjusts by automatically changing the traveling speed adjustment position of the machine, and controls so as to appropriately maintain the load of the working unit, the engine speed control unit controls the engine output to be the engine output. A first control mode that operates to maintain the detected value of the engine speed at a predetermined number of revolutions within a range less than or equal to the first output related to the characteristic of the engine, and a first control mode in which the engine output exceeds the first output. A work state detection configured to switch to a second control mode in which the detected value of the engine rotation speed is maintained within the range of the output of 2 or less to maintain the predetermined rotation speed, and detects the work state of the working unit. means A means for suspending the automatic change and for instructing the engine speed control unit to operate in the first control mode when a work state other than harvesting work is detected by the work state detecting means; A vehicle speed control device for a harvester, comprising: