JPH0736729B2 - Harvester vehicle speed controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vehicle speed control device for a harvester that operates to change a traveling speed according to an increase / decrease in load on a working unit such as a threshing unit and a cutting unit.

[Prior art]

The harvesting machine conveys the grain culms cut by the mowing section to the threshing section, and performs threshing and sorting processing at the threshing section to take out the fine grain, and the working sections such as the mowing section and the threshing section. While the load increases or decreases according to the amount of grain culm to be treated in these, the amount of grain culm to be treated increases or decreases according to the traveling speed of the harvester, the field conditions, and the like. Therefore, the conventional harvester is equipped with a vehicle speed control device that changes the traveling speed according to the increase or decrease of the load in the working unit so that the working unit can always perform the respective processing under an appropriate load condition. There is something.

The conventional vehicle speed control device detects the load of the working unit by, for example, the number of rotations of the threshing unit in the threshing unit, and when this exceeds a preset appropriate range (or falls below), the grain to be processed in the working unit The traveling speed is reduced (or increased) by a predetermined amount in order to reduce (or increase) the culm volume and reduce (or increase) the load on the working unit. (Japanese Patent Application No. 60-168707 (JP-A No. 62-29909)).

However, in such a vehicle speed control device, when the load of each part of the working unit other than the handling cylinder, for example, the cutting blade or the moving device in the mowing unit or the rocking sorting device in the threshing unit suddenly changes, the load changes suddenly. Is transmitted to the engine through the integrated transmission, the rotation speed of the engine decreases, and the reduced rotation speed is detected at the time when the rotation speed is transmitted to the handling cylinder through another transmission, There is a drawback that the detection of the load is delayed.

Therefore, a so-called isochronous-controlled engine that can rotate at a constant speed regardless of the size of the load is mounted on the harvester by adjusting the fuel supply amount according to the increase / decrease of the load. And the load of the working unit is detected as the load of the engine that sensitively reflects this, for example, by the position of the fuel rack of the engine, while the speed corresponding to the travel speed adjustment position of the transmission and the engine The relationship with the load is stored in advance so that the load on the working unit after the gear shift is within an appropriate range based on the above-mentioned stored contents based on the detection result of the engine load and the current traveling speed adjustment position. If the target value of the traveling speed adjustment position is obtained and operated to realize this, and the traveling speed is changed promptly, the above-mentioned difficulties are eliminated.

[Problems to be solved by the invention]

However, in the harvester equipped with the vehicle speed control device having the structure as described above, when the mowing of one stroke is finished and the shifting operation is performed in the headland, the load in the mowing section is rapidly reduced immediately after the mowing, In response to this, there is a risk that unnecessary increase in traveling speed will be performed, especially when the headland is narrow,
There was even a risk of a collision on the shore due to this speed increase. Therefore, in order to avoid this, if a delay time is provided between the detection of the decrease in load and the change of the traveling speed adjustment position for acceleration, responsiveness to the decrease in load during normal harvesting work is provided. However, there is a problem that the work efficiency deteriorates and the work efficiency decreases.

The present invention has been made in view of such circumstances, and unnecessary speedup is not performed at the time of shifting to the rounding operation in the headland, and further, the load of the engine is not increased during normal harvesting work. An object of the present invention is to provide a vehicle speed control device for a harvester that can quickly realize an optimum traveling speed adjustment position based on a detection result.

[Means for solving problems]

The vehicle speed control device for a harvester according to the present invention has an engine speed control unit that operates to maintain the engine speed at a set speed regardless of the magnitude of the load, and the traveling unit and the working unit are operated by the engine. It is equipped with a harvester that is driven to detect the load of the working unit as the load of the engine related to it, and travels to keep the load of the working unit within an appropriate range based on the detection result. In the vehicle speed control device of the harvester that adjusts the speed, when acceleration is required due to the detection result, means for delaying the execution for a predetermined time,
During this delay, there is provided a change rate calculating means for calculating a change rate of the load of the engine per unit time, and the load of the engine is shorter than the delay time according to the calculation result of the change rate calculating means. The present invention is characterized in that if the speed does not change or is increasing in a predetermined time, the acceleration is immediately executed, and in other cases, the acceleration is not executed.

〔Example〕

The present invention will be described below with reference to the drawings showing an embodiment thereof. FIG. 1 is an external perspective view of a harvester equipped with a vehicle speed control device according to the present invention (hereinafter referred to as the device of the present invention). In the figure, reference numeral 1 is a traveling crawler, and an engine (not shown)
Is transmitted to the traveling crawler 1 through the main clutch, the gear meshing auxiliary transmission, the main transmission using the power shift transmission, and the side clutch to drive the vehicle, while the traveling crawler 1 Upper part of the threshing unit 3, a swinging selection device (both not shown) and the like, and a cutting blade 41 and a moving device 42 provided on the cutting unit 4 at the front of the machine body.
Etc. are also driven by the driving force of the engine.

Reference numeral 6 in the drawing denotes an operation column provided on the side of the driver's seat DS. The operation column 6 is used to change the main shift lever 51 for changing the traveling speed stage of the main transmission and the traveling speed stage of the auxiliary transmission. The auxiliary shift lever 52, an accelerator lever 53 for changing the engine rotation speed, an automatic switch 9 for instructing the device of the present invention to start its operation, and the like are provided.

Further, 7 is a vertical transport chain, and its end is provided along the handling opening on the left side of the threshing unit 3, and the grain culm pinching and transporting device 8 is provided.
Of the feed chain 81, the grain culm cut by the reaper 4 is conveyed by the feed chain 81 and the pinching rod 82 of the vertical conveying chain 7 and the grain culm pinching and conveying device 8. Threshing processing is performed inside the threshing unit 3.

A grain culm sensor 71 is installed on the front surface of the threshing unit 3 in the vicinity of the end of the vertical transport chain 7, and the grain culm sensor 71 has a detection rod 72 protruding downward in the vertical transport chain 7. It is detected that the grain culm is fed to the grain culm unit 3 by bringing it into contact with a part of the grain culm to be conveyed.

FIG. 2 is a block diagram showing the configuration of the device of the present invention.
Is a vehicle speed control unit, and 30 is an engine speed control unit. The engine speed control unit 30 detects the engine speed,
In order to match the detection result with the set rotational speed, a fuel rack of the fuel injection pump (hereinafter referred to as a rack) is moved to perform so-called isochronous control for controlling the fuel supply amount to the engine. On the side, a rack position sensor 31 mounted coaxially with the rack for detecting the position of the rack, for example, a rack position sensor 31 using a differential transformer and mounted at an appropriate position of the engine, the rotation speed of the engine The engine speed sensors 32 for detecting the above are respectively connected, and an operation command signal is given from the vehicle speed control unit 10 as described later.

On the other hand, the output of the engine speed control unit 30 includes a rack actuator 33 that uses, for example, a linear solenoid that drives the rack, and an input port a ₈ of a vehicle speed control unit 10 described later.
Are given to each.

The engine speed control unit 30 includes a numerical table or an arithmetic expression for obtaining a corrected set speed that is set to restore the set speed to the set speed when the detected speed differs from the set speed due to a change in load. Of the correction setting rotational speed at the time of no load and the position of the rack that can obtain this, that is, a mathematical table or an arithmetic expression for obtaining the relationship between the rack position corresponding to the no load, the rack position corresponding to the no load and the detected rack position The rack position required to obtain the set number of rotations from, that is, a numerical table or an arithmetic expression for obtaining the target rack position, and the maximum allowable position of the rack at each number of rotations are stored.

Then, the engine rotation speed control unit 30 calculates the corrected set rotation speed when the detected rotation speed input from the engine rotation sensor 32 is different from the set rotation speed (the rated rotation speed in this embodiment) due to a change in the load. Then, the rack position equivalent to the no-load corresponding to the corrected set rotational speed is detected, and from this and the actual rack position input from the rack position sensor 31, the target rack required to obtain the corrected set rotational speed. The position is calculated and a signal corresponding to this target rack position is given to the rack actuator 33. In response to this signal, the rack actuator 33 operates to move the rack to the target rack position, and adjusts the fuel supply amount to the engine. In this way, the engine speed control unit
The engine 30 operates to maintain the engine speed at its rated speed regardless of the size of the load, but the operation of the control unit 30 is given an operation command signal from the vehicle speed control unit 10 as described later. It is supposed to be done only when.

On the other hand, the vehicle speed control unit 10 calculates the engine load from a signal corresponding to the target rack position given from the engine speed control unit 30, obtains a traveling speed stage that does not exceed the upper limit value, and realizes the traveling speed stage. Therefore, the traveling speed stage in the main transmission and the auxiliary transmission is changed.

The automatic switch 9 is connected to the input port a ₁ of the vehicle speed control unit 10.
Are connected, and when the switch 9 is turned on, the input port a ₁ changes to low level. Also, input ports a ₂ , a ₃ , a ₄
The threshing switch 11, which is turned on when the threshing clutch is engaged, the mowing switch 12 which is turned on when the mowing clutch is engaged, and the detection rod 72 of the grain culm sensor 71.
The grain culm switches 13 that are turned on when the grain culms come into contact with are respectively connected, and the input ports a ₂ , a ₃ , and a ₄ are turned to high level by turning on these switches. And the vehicle speed control unit 10 when the above switches are turned on,
That is, the input port a ₁ is at low level, and the input port a ₂ ,
only operates when a _3, a ₄ are both high level, controls the speed of the harvester.

The auxiliary speed change lever 52 is connected to the input ports a ₅ and a ₆ of the vehicle speed control unit 10.
Is arranged at the base end of the lever 52 and is turned on by the locking position of the lever 52,
The first and second auxiliary transmission switches 14 and 15 which are turned off are connected to each other, and the input port a ₅ is input when the first auxiliary transmission switch 14 is turned on, and the input port a ₅ is input when the second auxiliary transmission switch 15 is turned on. Port a ₆ turns to low level, respectively. The auxiliary transmission device has three traveling speed stages, that is, "low speed stage", "medium speed stage" and "high speed stage", and the first auxiliary transmission switch.
14 indicates that the sub shift lever 52 is in the locking position corresponding to the "low speed stage", and the second sub shift switch 15 is in the locking position where the sub shift lever 52 corresponds to the "high speed stage". In some cases, the vehicle speed control unit 10 is arranged so as to be turned on respectively.
, By the input port a ₅ is at low level, by said running speed stage of the auxiliary speed change device is a "slow stage", also has an input port a ₅ is at low level, like "high gear" The fact that the input ports a ₅ and a ₆ are both at the high level makes it possible to recognize that they are also “medium speed stages”.

To the input port a ₇ of the vehicle speed control unit 10, a shift sensor 16 that is mounted on the base end pivotal support portion of the main shift lever 51 and outputs a potential according to the amount of rotation thereof and that uses a potentiometer is connected. . The main transmission has four forward speeds and one reverse speed.
The vehicle has six speed stages, namely, high speed and neutral speed stages, and the vehicle speed control unit 10 determines which state of the main speed device the travel speed stages are in, depending on the level of the signal input to the input port a ₇ . recognize.

Further, a signal corresponding to the target rack position which is the output of the engine speed control unit 30 is given to the input port a ₈ of the vehicle speed control unit 10 as described above.

The signals input to the input ports a ₇ and a ₈ are subjected to predetermined processing by the input interface of the vehicle speed control unit 10, and are transferred to the CPU 10a of the vehicle speed control unit 10 as digital data corresponding to the level of each signal. It is designed to be crowded.

On the other hand, the output ports b ₁ and b ₂ of the vehicle speed control unit 10 are connected to the main shift lever.
51 The shift motor 20 for rotation is connected through a drive circuit (not shown), and the shift motor 20 rotates normally (or reversely) in response to the high level output of the output port b ₁ (or b ₂ ). The shift lever 51 is rotated to a high speed (or low speed) running side.

The output port b ₃ of the vehicle speed control unit 10 has a vehicle speed lamp 21 for informing the operator that the vehicle speed control operation is being performed.
Further, the output ports b ₄ and b ₅ are connected to a speed-up instruction lamp 22 and a deceleration instruction lamp 23, respectively, for instructing an operator to operate the auxiliary shift lever 52 to the high speed side and the low speed side, output port b _3, b ₄ each lamp in accordance with the low level output of, b ₅ is adapted to be respectively turned on.

The output port b ₆ of the vehicle speed control unit 10 is connected to a buzzer 24 for outputting various alarms, and the buzzer 24 sounds according to the high level output of the output port b ₆ .

The output port b ₇ of the vehicle speed control unit 10 is connected to the input side of the engine speed control unit 30, and the engine speed control unit connected to the output port b ₇ according to the high level output of the output port b _7. When the input port of 30 becomes high level, the control unit 30 operates as described above, and the engine of the harvester is
Regardless of the magnitude of the load applied to it, it is rotated at a constant speed at its rated speed.

The vehicle speed control unit 10 is a CPU 10 that performs input / output instructions and control calculations.
a, a RAM 10b used for control calculation in the CPU 10a, and a ROM 10c storing various data and control programs necessary for control calculation. FIG. 3 is a graph of load characteristics showing the relationship between the traveling speed of the harvester and the load of the engine when the engine speed is the rated speed. One of the above data is stored in the ROM 10c. Remembered The horizontal axis of FIG. 3 shows the traveling speed V, and the vertical axis shows the load factor E with respect to the maximum load of the engine. F _{1 to} F _n indicate the actual harvesting work under various load conditions. It is a load characteristic curve obtained by performing.

Further, L _{1 to} L ₄ , M _{1 to} M ₄ and H ₁ and H ₂ in FIG. 3 are reference numerals indicating traveling speed stages, and L, M and H are traveling speed stages in the auxiliary transmission. The "low speed stage", "medium speed stage", and "high speed stage", and 1,2,3,4 the traveling speed stage in the main transmission is "first forward speed stage", "second forward speed stage", respectively. Dan ",
It indicates that it is a “third forward speed” and a “fourth forward speed”. As described above, the graph of FIG. 3 is obtained under the condition that the engine is rotating at a constant speed at the rated rotation speed, and therefore each code indicating the traveling speed stage corresponds to the traveling speed. To do.

Further, E _{cmax in} FIG. 3 is a limit maximum load ratio, which is an upper limit value of the load for limiting the load applied to the engine during the vehicle speed control operation to this value or less, and is 85 to 90 of the maximum load of the engine.
Set to%, stored in ROM 10c.

Now, the operation of the device of the present invention configured as described above will be described with reference to the flowcharts showing the control contents of the vehicle speed control unit 10 in FIGS. 4, 5, and 6.

When the vehicle speed control unit 10 is connected to the power supply by turning on the key switch for starting the engine, first, the on / off state of the automatic switch 9 is monitored by the level of the input port a ₁ , and the automatic switch 9 is turned on. When the input port a ₁ turns to low level, the output port b _{7 is set} to high level to issue an operation command to the engine speed control unit 30, and the operation of the control unit 30 causes the engine of the harvester to be rated thereafter. Rotate at a constant speed at the number of revolutions.

Next, the vehicle speed control unit 10 checks the on / off states of the threshing switch 11, the reaping switch 12, and the grain culm switch 13 according to the levels of the input ports a _{2 to} a ₄ , and all of these switches are turned on, and the input port a ₂ at the time the ~a ₄ becomes all high level, starts its speed control operation, first turn the output port b ₃ to the low level, and allowed to light the vehicle lamp 21, the vehicle speed control operation is performed to the operator The control unit 10 thereafter informs that the load factor in the engine does not exceed the maximum load factor E _cmax , in order to obtain the highest work efficiency. Select and operate to achieve this to change the harvester's running speed.

After turning on the vehicle speed lamp 21, the vehicle speed control unit 10 determines the rack position R according to the level of the input signal to the input port a ₈ and the traveling speed in the main transmission according to the level of the input signal to the input port a ₇ . Gear (hereinafter referred to as main gear) A
Further, the traveling speed stage (hereinafter referred to as the auxiliary shift stage) B in the auxiliary transmission is recognized by the levels of the input ports a ₅ and a ₆ , respectively, and then the rack position R is used to calculate the arithmetic expression stored in the ROM 10c. Based on this, the input load factor ε corresponding to the current load factor in the engine is calculated. And the vehicle speed control unit 10
Compares the input load factor ε with the limited maximum load factor E _cmax, and when ε is equal to or less than E _cmax , performs vehicle speed control operation according to a speed increasing control subroutine described later, and ε is E
If it is larger than _{cmax, the} following operation is performed in order to change the traveling speed stage in the main transmission device or the sub transmission device from the current main transmission stage A or the sub transmission stage B to the one-step lower speed side.

That is, the vehicle speed control unit 10 checks whether or not the current main gear A is 1 (first forward gear), and if A is not 1 and deceleration is possible by changing the main gear, the output port b _{2 is set} to a high level, the shift motor 20 is reversely rotated by a predetermined amount, and the main shift stage is changed to the one-step lower speed side. If A is 1, then it is checked whether or not the auxiliary gear B is L (low speed). If B is not L and deceleration is possible by changing the auxiliary gear, that is The output port b _{5 is set} to the low level, the deceleration instruction lamp 23 is turned on to instruct the operator to operate the auxiliary shift lever 52 to the low speed side, and the input ports a ₅ and a ₆
The output port b _{6 is set} to a high level at a predetermined time interval of T ₁ sec until the operation is performed, and the buzzer 24 sounds intermittently. Let

In this way, when the deceleration is performed by changing the main shift stage or the sub shift stage, the threshing unit 3 is decelerated according to the traveling speed after the deceleration.
The predetermined time (T ₂ ) set in consideration of the time required until the amount of grain culm sent to
sec) After waiting, the vehicle speed control unit 10 determines whether or not the above conditions for starting the vehicle speed control are satisfied, that is, the automatic switch 9, the threshing switch 11, the reaping switch 12 and the culm switch 13 are all turned on. If it is satisfied, the process returns to the stage of recognizing the rack position R, the main shift stage A and the sub shift stage B, and the same operation is repeated thereafter. Further, when the condition is not satisfied, the vehicle speed control unit 10, turn its output port b ₃ to the high level, and allowed to turn off the vehicle lamp 21, pauses vehicle speed control operation until the condition is satisfied Switch to standby mode.

Further, when the current main gear A is 1 and the sub gear B is L and it is impossible to reduce the traveling speed by changing the gear, the vehicle speed control unit 10 outputs the output port.
The b ₂ to the high level, the main gear is reversely rotates the shift motor 20 until neutral, to stop the aircraft, and the output port b ₆ to the high level causes the buzzer 24 for a predetermined time ringing, the output port b ₃ Is set to a high level and the vehicle speed lamp 21 is turned off, and then the operation ends. This is a state in which an excessive load is applied to any part of the working parts such as the threshing part 3 and the mowing part 4. In this case, the operator temporarily stops the engine and inspects each part After removing the cause of the various loads, the vehicle speed control unit 10 restarts the operation by operating the key switch and restarting the engine.

As described above, the input load factor ε is limited to the maximum load factor E _cmax
If ε is less than or equal to E _cmax when compared with
The vehicle speed control unit 10 operates according to a speed-up control subroutine whose flowchart is shown in the figure.

In the speed-up control subroutine, first, the current load state is specified from the input load factor ε and the current main shift stage A and the sub shift stage B, and the load characteristic curves that match this are F _{1 to} F shown in FIG. Selected from _n . For example, if the current traveling speed stage is “M3” and the input load factor is ε, the current load state is specified at point C in FIG. 3 and the load characteristic curve indicated by F _{i in} FIG. Is selected.

Then, the vehicle speed control unit 10 determines that the traveling speed stage “H
2 "in order from the traveling speed stage corresponding to the current main speed stage A and the sub-speed stage B to the traveling speed stage one step higher than the traveling speed stage, the load factor on the load characteristic curve F _i. E _i is calculated, and this is compared with the limited maximum load factor E _cmax, and the main shift stage a and the sub shift stage b at the time when E _i becomes smaller than E _cmax are set as the target travel speed stages, and In order to realize the above, the speed increasing control operation for changing the traveling speed stage in the main transmission and / or the auxiliary transmission is performed as described later. Further, the load factor E _i calculated at each traveling speed stage
_Are all above the maximum limit load factor E _cmax , the vehicle speed control unit 10 determines that the current main gear stage A and the sub gear stage B are the optimum traveling speed stages, and the speed increase control operation is performed. The control operation according to the speed-up control subroutine is immediately ended without performing the above, and the process returns to the predetermined stage of the flowchart of FIG.

Now, when the target traveling speed stages a and b are obtained, the vehicle speed control unit 10 does not immediately start its operation in order to realize the traveling speed stages a and b, but first, FIG. The state of change of the load factor of the engine is monitored in accordance with the change rate monitoring subroutine shown in the flowchart. In the change rate monitoring subroutine, the vehicle speed control unit 10 first resets the flag F indicating that the load rate has not changed for a predetermined time or is increasing, starts the time measurement of the timer t ₃ , and then reads the rack position R. Then, the input load factor ε is calculated using this.

Then, the input load factor ε and the previously calculated input load factor ε
By calculating the change rate dε / dt of the load factor in the engine, if dε / dt is negative, that is, the load factor tends to decrease, the flag F is reset and the content of the timer t ₃ is preset. Check whether or not it has exceeded the predetermined time T ₃
If the content of the timer t ₃ is less than the predetermined time T ₃ ,
The next rack position R is read, the input load factor ε is calculated, the same operation is repeated, and the content of the timer t ₃ is the predetermined time.
When it becomes equal to or higher than T _3, the process returns to the predetermined stage of the acceleration control subroutine.

When the change rate dε / dt of the load factor is 0 or positive, that is, when the load factor does not change or is increasing, the vehicle speed control unit
10 checks whether or not the flag F is 1, and checks the flag F
If but not 1, to start counting of the timer t _4, after waiting until the contents of the timer t ₄ becomes sufficiently small predetermined time T ₄ than the predetermined time T _3, and sets the flag F Return to a predetermined stage to read the next rack position R,
If the flag F is 1, the process immediately returns to the predetermined stage of the speed-up control subroutine.

After ending the operation according to the change rate monitoring subroutine in this way, the vehicle speed control unit 10 checks the state of the flag F that is set or reset in the change rate monitoring subroutine, and when F is 1, the target In order to realize the traveling speed stages a and b, first, the current sub-shift stage B and the target sub-shift stage b are compared. When B = b and it is not necessary to change the sub-shift stage, the vehicle speed control unit 10 determines that the output port
With b _{1 set} to a high level, the shift motor 20 is normally rotated until it is confirmed by the level of the signal input to the input port a ₇ that the main shift stage has become the target main shift stage a. If B ≠ b and it is necessary to change the auxiliary gear,
Similarly to the deceleration control operation described above, the vehicle speed control unit 10 sets its output port b ₄ to the low level to turn on the speed increasing instruction lamp 22 in order to instruct the operation of the auxiliary shift lever 52 to the speed increasing side. , The output port b _{6 is set} to the high level at the time interval of T ₁ sec until it is confirmed by the levels of the input ports a ₅ and a ₆ that the sub gear stage becomes the target sub gear stage b, and the buzzer 24 Sound intermittently. Then, when it is confirmed that the sub shift lever 52 has been operated and the sub shift stage has become b, the vehicle speed control unit 10 immediately performs the above-described operation so as to set the main shift stage to the target main shift stage a. .

After changing the traveling speed stage for acceleration in this way, the vehicle speed control unit 10 waits for a predetermined time of T ₂ sec, and then ends the control operation according to the acceleration control subroutine.
The process returns to the predetermined stage of the flowchart of FIG. On the other hand, when the flag F is in the reset state, it immediately returns to the predetermined stage of the flowchart of FIG. 4 without changing the traveling speed stage as described above. And vehicle speed control
10 confirms whether or not the conditions for starting the control described above are satisfied, and if not satisfied, shifts to the standby mode described above, and if satisfied, a new rack position R Then, the main shift stage A and the sub shift stage B are recognized, and a series of vehicle speed control operation units are continued based on these.

As described above, in the vehicle speed control unit 10, after the target traveling speed stages a and b are obtained, the target traveling speed stages are set according to the set state of the flag F which is set or reset in the change rate monitoring subroutine. It is determined whether or not to increase the speed by changing the traveling speed stage to. As a result, immediately after the end of the one-step cutting, the load on the engine is reduced due to a sudden decrease in the load on the cutting blade 41 and the raising device 42 of the cutting unit 4, and the load on each part of the working unit during normal harvesting work. It is distinguished from the case where the load on the engine is reduced due to the change in the state. In the former case, it is prevented that the acceleration is performed according to the decrease in the load on the engine. In the latter case, the target traveling speed stage a And the required speed increase is promptly performed by changing the traveling speed stage to b.

That is, in the former case, after the load on the mowing unit 4 decreases sharply, the amount of grain culm transported by the vertical transport chain 7 decreases as the harvester further travels, and then the amount of threshing treatment on the handling cylinder. Is gradually decreased, and further, the amount of sorting processing in the swing sorting device is gradually reduced, and the load of the engine that drives them tends to be gradually reduced for a considerably long time immediately after the end of mowing. Therefore, the above-mentioned predetermined time T ₃ in the change rate monitoring subroutine is more than the time required for the vertical transfer chain 7 to convey the grain culm to the installation position of the grain culm sensor 71 after the grain culm is mowed by the operation of the mowing unit 4. Sufficiently long, if set to an appropriate time shorter than the time required to complete the threshing process in the barrel of the grain culm, the engine load at the end of mowing is at least this predetermined time T ₃ In the meantime, it is decreasing. Therefore, when the vehicle speed control unit 10 operates in accordance with the speed-up control subroutine to increase the traveling speed by detecting the reduction of the engine load at the end of the mowing, the target traveling speed stage a
And b) are obtained, and after the series of processing in the change rate monitoring subroutine is completed, the flag F becomes a reset state and returns to the acceleration control subroutine. Since the flag F is in the reset state, the vehicle speed control unit
Reference numeral 10 indicates that the speed increasing control subroutine immediately shifts to a predetermined step in the flowchart of FIG. 4 without operating to change the running speed step to the target running speed steps a and b.
Next, it is checked whether or not the conditions for starting the vehicle speed control are satisfied. The predetermined time T ₃ as described above, since culms was reaped is set longer than the time required for being conveyed to the position of the culms sensor 71, cutting the predetermined time T ₃ from the end of the elapsed At the time of doing, the harvested grain culm has already passed the installation position of the grain culm sensor 71,
At the time of checking whether or not the above-mentioned control start condition is satisfied, the grain culm switch 13 is in the off state, and the above condition is not satisfied. Therefore, after that, the vehicle speed control unit 10 shifts to the standby mode, finishes the turning in the headland, the cutting of the next stroke is started, and the head part of the cut grain is located at the position of the grain sensor 71. This standby mode is maintained until the grain culm switch 13 is turned on and the traveling speed of the harvester is maintained at a constant speed.

On the other hand, in the latter case, after the load of the engine is once reduced due to the change of the load state, the load of the engine stabilizes at a value according to the new load state within a relatively short time. Therefore, when the vehicle speed control unit 10 operates in response to the decrease of the engine load, the engine load is stabilized before the predetermined time T ₃ elapses, and the change rate of the load rate obtained in the change rate monitoring subroutine. When dε / dt becomes 0 or a positive value and this state continues for the predetermined time T ₄ , the flag F becomes the set state and the process returns to the speed-up control subroutine. Then, since the flag F is in the reset state, the vehicle speed control unit 10 operates as described above to realize the target traveling speed stages a and b obtained previously, and the main shift stage and / or the sub shift stage are changed. By changing the speed, the traveling speed of the harvester is increased to a speed according to the new load condition.

〔effect〕

As described above in detail, in the device of the present invention, the target position of the traveling speed adjusting position is obtained based on the detected value of the load of the engine, and this is on the higher speed side than the current traveling speed adjusting position, and it is necessary to increase the speed. When it becomes, whether or not to operate to realize the target position is determined based on the calculation result of the change rate calculation means, so that the one-step cutting is completed and the headland also shifts to the turning motion. There is no unnecessary speedup when doing so, and the risk of collision with the shore is avoided, while the required speedup is promptly performed to reduce the load on the working section during normal harvesting work. Is performed, and excellent effects such as improved work efficiency are achieved.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a perspective view of a harvester equipped with the device of the present invention, FIG. 2 is a block diagram showing the configuration of the device of the present invention, and FIG. Graphs showing the relationship between speed and engine load, and FIGS. 4, 5, and 6 are flowcharts showing the control contents of the vehicle speed control unit. 3 ... Threshing part, 4 ... Mowing part, 9 ... Automatic switch 10 ... Vehicle speed control part, 14, 15 ... Auxiliary shift switch 16 ... Shift sensor, 20 ... Shift motor 30 ... Engine speed control part

Claims (1)

[Claims] Claim: What is claimed is: 1. An engine speed control unit is provided which operates to maintain the engine speed at a set speed regardless of the load, and the running unit and the working unit are driven by the engine. The harvester is equipped with a load on the working unit,
In the vehicle speed control device of the harvester that detects the load of the engine related to this and adjusts the traveling speed so that the load of the working unit is within the proper range based on the detection result, acceleration is required by the detection result. In the case of the above, there is provided a means for delaying the execution for a predetermined time, and a change rate calculation means for calculating the change rate of the load of the engine per unit time during this delay. According to the calculation result, if the engine load does not change or tends to increase in a predetermined time shorter than the delay time, the speed increase is immediately performed, and in other cases, the speed increase is performed. A vehicle speed control device for a harvester, which is characterized in that it does not execute.