JPH074103B2 - Harvester vehicle speed controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vehicle speed control device for a harvester that increases / decreases a traveling speed in accordance with 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, threshes at the threshing section, sorts and picks out the fine grain, and the working sections such as the mowing section and the threshing section. The load increases or decreases depending on the amount of grain culm to be processed in these,
The amount of grain culm to be processed increases or decreases according to the traveling speed of the harvesting machine and the field conditions. Therefore, the conventional harvester is equipped with a vehicle speed control device that changes the traveling speed of the harvester according to the increase or decrease of the load in the working unit so that the working unit is always operated under an appropriate load condition. There is something.

This vehicle speed control device, for example, detects the load of the working part by the number of rotations of the threshing part of the threshing part, and when this detected value exceeds a preset proper range, the amount of grain culm to be processed in the working part. In order to reduce the load on the working unit, the traveling speed is reduced by a predetermined amount, and when the detected value falls below the appropriate range and there is a margin in the output of the engine that drives the working unit, the working unit Increase the amount of grain culm to be processed in
The running speed is increased by a predetermined amount in order to increase the load on the working unit, and the running speed is increased or decreased by changing the running speed adjusting position of the transmission (Japanese Patent Application No. 60-168707).
(JP-A-62-29909).

[Problems to be solved by the invention]

As described above, the conventional vehicle speed control device, when the number of rotations of the handling cylinder is increased or decreased according to the load of the working unit and is out of the proper range, the traveling speed is kept until the value becomes within the proper range. Since the detected value of the number of revolutions deviates significantly from the proper range because of the stepwise change, and multiple shifts are required to return the detected value to the proper range, the predetermined value of the traveling speed is set once. After making the change, wait until the load on the working unit increases and decreases according to this speed and stabilizes, and then change the next running speed according to the detected value of the rotation speed of the handling cylinder after stabilization. However, it takes a considerable time to change the traveling speed, and during that time, each process is performed in the working unit under an overload or underload condition, and the engine driving the working unit is overloaded. The difficulty is that you have to drive under the ground or work efficiency decreases. Was Tsu.

In order to eliminate this difficulty, if the amount of change in one running speed is made large, for example, when the detected value of the number of rotations of the handling cylinder exceeds the appropriate range and the running speed is decelerated, the speed after deceleration On the contrary, the load of the working unit corresponding to the above may fall below the appropriate range, the traveling speed may be increased, and the acceleration / deceleration may be repeated thereafter, so-called hunting may occur.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a vehicle speed control device for a harvester in which acceleration / deceleration to a proper traveling speed is immediately performed according to a detected value of a load of a working unit. And

[Means for solving problems]

The vehicle speed control device for a harvester according to the present invention has an engine rotation speed control unit that operates to maintain the rotation speed of the engine at a set rotation speed regardless of the magnitude of the load. In the vehicle speed control device of the harvester for controlling the traveling speed, which is provided in the harvester that is driven, the traveling speed adjustment position of the transmission is changed according to the load of the working portion, and the load of the working portion is controlled. The load detection means for detecting the load of the engine, the position detection means for detecting the travel speed adjustment position, and the relationship between the load of the engine and the travel speed at each travel speed adjustment position, One of the plurality of load characteristics is selected from the characteristic storage means for storing in the form of a plurality of load characteristics according to the load state, and the detection results of the load detection means and the position detection means. Wherein calculating a load of the engine to be expected at each running speed adjustment position, characterized by comprising a means for changing the traveling speed adjusting position based on the calculation result in accordance with.

[Action]

In the present invention, the load of the working unit is detected as the load of the engine and the traveling speed is detected as the traveling speed adjusting position of the transmission, respectively, and the load characteristics corresponding to the current load of the working unit are detected by the characteristic storage means. Selected from the stored contents, the engine load at each traveling speed adjustment position is calculated according to the characteristic, and the traveling speed adjustment position is changed so as to obtain an appropriate load state in the engine, and the traveling speed is controlled. Is done.

〔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 part 3, a swinging selection device (both not shown), and the like, and a cutting blade 41 and a raising device 42 provided on the cutting part 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, the end of which faces the starting end of the feed chain 81 of the grain-culm pinching and transporting device 8 provided along the left side of the threshing device 3 and the cutting unit. The grain culms harvested in 4 are transported by the vertical transport chain 7 and the feed chain 81 and the sandwiching rod 82 of the grain culm sandwiching and transporting device 8 and subjected to threshing processing 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 threshing 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. In the figure, 10 is a vehicle speed control unit and 30 is an engine speed control unit. The vehicle speed control by the device of the present invention is possible only in a harvester equipped with an engine capable of rotating at a constant speed regardless of the size of the load, and the engine speed control unit 30 detects the engine speed and detects the detected speed. Is to perform so-called isochronous control for controlling the fuel supply amount to the engine so as to match the set rotational speed. First, the control content of the engine rotational speed control unit 30 will be briefly described.

An input side of the engine speed control unit 30 is mounted on a fuel rack (hereinafter referred to as a rack) of a fuel injection pump (not shown) attached to the engine and detects the position of the rack, for example, a differential transformer. Is mounted on the engine and a rack position sensor 31 using, the engine rotation sensor 32 for detecting the number of revolutions of the engine is connected,
The output of the engine speed control unit 30 is the input port of the vehicle speed control unit 10 and a rack actuator 33 that drives the rack, for example, a rack actuator 33 using a linear solenoid.
They are given respectively to a _8.

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 (in this case, the rated rotation speed) due to a change in the load. , A signal for moving the rack to the target rack position by reading out the rack position corresponding to the correction setting number of revolutions, calculating the target rack position from the read rack position corresponding to no load and the actual rack position 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 rotation speed control unit 30 causes the engine to rotate at a constant speed at the rated rotation speed of the engine regardless of the size of the load due to its operation.

On the other hand, the input ports a _{1 to} a ₄ of the vehicle speed control unit 10 are
A signal is given to 10 to start its operation. The input port a _1, the provided automatic switch 9 is sustained, the input port a ₁ by turning on of the switch 9 is turned to a low level. The input ports a ₂ , a ₃ , and a ₄ have a threshing switch 1 that is turned on when the threshing clutch is engaged.
1, when the cutting clutch is engaged, the cutting switch 12 and the grain culm switch 13 that is turned on when the grain culm is in contact with the detection rod 72 of the grain culm sensor 71 are connected, respectively. By turning on each switch, the input ports a ₂ , a
₃ and a ₄ each turn to a high level. And the vehicle speed control unit 10
Operates only when the respective switches are turned on, that is, when the input port a ₁ is at a low level and the input ports a ₂ , a ₃ , a ₄ are at a high level, the vehicle speed of the harvester is To control.

The input ports a ₅ and a ₆ of the vehicle speed control unit 10 are connected to the auxiliary shift lever 5
The first and second sub-transmission switches 14 and 15 which are arranged at the base end of the second lever 52 and are turned on and off by the locking position of the lever 52 are connected to each other, and The input port a ₅ turns to a low level when turned on, and the input port a ₆ turns to a low level when the second auxiliary transmission switch 15 turns on. The auxiliary transmission device has three traveling speed stages, that is, "low speed stage", "medium speed stage", and "high speed stage". The second auxiliary shift switch 15 is turned on when the auxiliary shift lever 52 is in the locking position corresponding to the "low speed" and the auxiliary shift lever 52 is in the locking position corresponding to the "high speed". The vehicle speed control unit 10 is provided, because the input port a ₅ is at a low level,
By the fact that the speed stage of the auxiliary speed change device is a "slow stage", also has an input port a ₆ is at low level,
Similarly, input ports a ₅ and a ₆
Both are at "high speed", so "medium speed stage"
Recognize that each is.

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 speed control unit 10 has six types of traveling speed stages, namely, high speed and neutral, and the vehicle speed control unit 10 determines which of the traveling speed stages of the main transmission will depend on the level of the output signal of the shift sensor 16 input to the input port a ₇ . Recognize whether or not

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.

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

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

Output port b ₃ of the vehicle speed control unit 10, the vehicle speed lamp 21 for informing that the vehicle speed control is performed to the worker, also the output port b ₄ and the b _5, increasing of the subtransmission lever 52 The operation to the speed side and the deceleration side is respectively connected to the speed-up instruction lamp 22 and the deceleration instruction lamp 23 for instructing the operator,
Output port b _3, b _4, b ₅ is adapted to the respective lamp is turned to be a low level.

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 when the output port b ₆ becomes high level.

Further, 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, the output port b ₇ becomes high level, the engine speed control unit 30 of the output port b ₇ connected to this. When the input port goes high, the control unit 30
Will start its operation, and the output port b ₇
Is at a high level, the engine of the harvester rotates at a constant speed at the rated speed regardless of the load by the operation of the engine speed control unit 30 as described above.

The vehicle speed control unit 10 is a CPU 10 that performs input / output instructions and control calculations.
a, RAM 10b used for control calculation of CPU 10a, and various data and control programs necessary for control calculation are stored.
It consists of ROM 10c. 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, the horizontal axis being the running speed V, and the vertical axis. Is the load factor E with respect to the maximum load of the engine.

By the way, even if the traveling speed of the harvester is constant, the load on the working parts such as the threshing part 3 and the mowing part 4 is the planar density of the grain culms to be mowed on the field surface and the number of grains adhering to the grain culms, etc. The curves shown as F _{1 to} Fn in FIG. 3 are load characteristic curves obtained by actually performing harvesting work under various different working conditions. Further, since the engine is rotating at a constant speed, the traveling speed of the harvester is determined by the traveling speed stage in the main transmission and the auxiliary transmission. In FIG. 3, L1 to L4, M1 to M4 and H1 and H2 are symbols indicating the traveling speed stages, and L, M, and H are the traveling speed stages in the auxiliary transmission, respectively, the "low speed stage", "Medium speed stage" and "high speed stage", and 1,2,3,4 indicate that the traveling speed stage in the main transmission is "first forward speed", "second forward speed",
It shows that it is "three forward speeds" and "fourth forward speeds".
The curve shown as ΔE in FIG. 3 is a load fluctuation curve showing the fluctuation amount of the load at each speed.
Is a limit maximum load factor for limiting the load applied to the engine to below this value during vehicle speed control, and is set to 85 to 90%.

Now, F _{1 to} Fn and ΔE shown in FIG. 3 are stored in the ROM 10c as a mathematical table or an approximate expression approximating these,
The value of Ecmax is also stored in the ROM 10c. ROM 10
In addition to these, in c, various data such as an arithmetic expression for calculating the load factor E from the rack position of the fuel injection pump, a mathematical expression, etc. are stored.

Now, the operation of the device of the present invention configured as described above will be described based on the flowchart showing the control content of the vehicle speed control unit 10 shown in FIG.

The vehicle speed control unit 10 has a control start condition that the threshing unit 3 and the reaping unit 4 are operating together, that the grain culms are fed to the threshing unit 3, and that the automatic switch 9 is turned on. As mentioned above, all are satisfied.
performing speed control operation only when it is confirmed by the level of a ₁ ~a _4.

When each of the above conditions is satisfied, the vehicle speed control unit 10 first sets the output port b ₃ to a low level, lights the vehicle speed lamp 21, and notifies the operator that the vehicle speed control is being performed, and outputs the output. The port b _{7 is set} to the high level, and the engine speed control unit 30 is instructed to start its operation. After that, the engine of the harvester rotates at a constant speed at the rated speed by the operation of the engine speed control unit 30.

Next, the vehicle speed control unit 10 determines the rack position R from the signal input to the input port a ₈ and the traveling speed stage (hereinafter referred to as the main shift position) A in the main transmission from the signal input to the input port a _7. By the level of input ports a ₅ and a ₆ ,
As described above, each traveling speed stage (hereinafter referred to as the sub-shift position) B in the sub-transmission device is recognized. Then, using the rack position R, the input load factor ε is calculated according to the arithmetic expression stored in the ROM 10c. The input load factor ε calculated in this way
May be used as it is for subsequent calculations, but in an engine that is isochronously controlled, its rack position is frequently changed, so vehicle speed control is performed by the peak value of the instantaneous rack position R. Therefore, it is desirable to use the moving average value of the input load factor ε calculated as described above for the subsequent calculation.

Next, the vehicle speed control unit 10 compares the input load factor ε with the limited maximum load factor Ecmax stored in the ROM 10c, and ε is Ecm.
If it is equal to or less than ax, the subsequent processing is shifted to the speed-up control subroutine D described later. Further, when ε is larger than Ecmax and deceleration is required, it is first determined whether the main shift position A is 1, that is, the main shift position is the "first forward speed".
If A is not 1 and the traveling speed can be decelerated by changing the main shift position, the output port b ₂ thereof is set to the high level for a predetermined time, and the shift motor 20 is moved by a predetermined amount. Reverse to reduce the running speed.

When A is 1 and the traveling speed cannot be reduced by changing the main shift position, the vehicle speed control unit 10 determines whether the sub shift position B is L, that is, the sub shift position is If it is possible to reduce the traveling speed by changing the auxiliary shift position by checking whether or not it is the “low speed stage”, the output port b _{5 is set} to the low level, and the deceleration instruction lamp is set. 23 is turned on and the operator is instructed to operate the auxiliary shift lever 52 toward the deceleration side. Thereafter, the vehicle speed control unit 10 checks whether or not the auxiliary shift lever 52 is operated by monitoring the change in the level of the input ports a ₅ and a ₆ , and outputs the output when the operation is not performed. After setting the port b ₆ to a high level and causing the buzzer 24 to ring, after waiting for a predetermined time (T ₁ sec), the same operation is repeated. That is, when the operator misses the lighting of the deceleration instruction lamp 23 and the sub shift lever 52 is not operated, the buzzer 24 is operated until the sub shift lever 52 is operated.
Is intermittently sounded at a time interval of T ₁ sec to instruct the operator to operate the lever 52. When it is confirmed that the auxiliary shift lever 52 has been operated and the traveling speed has been decelerated by changing the auxiliary shift position, the vehicle speed control unit 10 turns the output port b ₅ to the high level and outputs the deceleration instruction. Turn off the lamp 23.

In this way, after the traveling speed is reduced by the reverse rotation of the shift motor 20 or the operation of the auxiliary shift lever 52, the vehicle speed control unit 10 determines the time required until the load on the threshing unit 3 decreases according to the changed traveling speed. In other words, the control start condition is satisfied after waiting for a predetermined time (T ₂ sec) set in consideration of the time required for the culms cut by the cutting unit 4 to be conveyed to the threshing unit 3. If it is satisfied, the process returns to the first stage of the flowchart and the above-mentioned operation is repeated. If the above condition is not satisfied, the vehicle speed control operation is suspended until the condition is satisfied again.

Further, when it is previously checked whether or not the auxiliary shift position B is L and B is L, and the traveling speed cannot be reduced by changing the auxiliary shift position, the vehicle speed control unit 10 The output port b _{2 is set} to a high level, the shift motor 20 is continuously rotated in the reverse direction until the main shift position reaches the neutral position, the traveling of the aircraft is stopped, and then the output port b _{6 is set} to a high level to ring the buzzer 24. After that, the vehicle speed control operation is stopped. 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 returns to the original state by restarting the engine.

Now, FIG. 5 is a flowchart of the speed-up control subroutine D. When the input load factor ε is compared with the limited maximum load factor Ecmax, the vehicle speed control unit 10
Shifts the subsequent processing to the speed-up control subroutine D.
In the subroutine D, the previously calculated input load factor ε and the previously recognized main shift position A and sub shift position B are detected.
Based on the above, first, the load characteristic curve Fi that matches the current load state is selected from the plurality of load characteristic curves F _{1 to} Fn stored in the ROM 10c. For example, the main shift position A is 3,
When the auxiliary shift position B is M, the current load state is
The characteristic curve identified by point C on the graph showing the load characteristic of FIG. 3 and indicated by Fi in FIG. 3 is selected. If there is no match among the load characteristic curves F _{1 to} Fn, the two load characteristic curves Fi and F _{i + 1} close to the above-mentioned load state.
The following two are selected, and the later-described calculation performed based on them is performed by linear interpolation between the curve Fi and the curve F _{i + 1} .

Then, the vehicle speed control unit 10 sets the register a indicating the main shift position to 2, the register b indicating the auxiliary shift position to H, the auxiliary shift position B to the contents of the register b, and the main shift position A to the contents of the register a. And B = b, and A
= A, without increasing the traveling speed,
The control operation according to the speed-up control subroutine D is ended. When B ≠ b or A ≠ a, the load characteristic curve when the main shift position is a and the sub shift position is b
The load factor Ei on Fi and the load change amount ΔEi on the load change curve ΔE at that time are calculated, respectively, and then Ei
+ ΔEi is compared with the limited maximum load factor Ecmax. Then, when Ei + ΔEi is equal to or more than Ecmax, the content of the register a is examined next, and when a is 1, the content of the register b is updated to the low speed side by one step, and a is set to 4, and then a If is not 1, the contents of the register a are updated to the low speed side by one step, and then the process returns to the stage of comparing the auxiliary shift position B with the contents of the register b and the main shift position A with the contents of the register a. The above operation is repeated. In the register a, the content of the register is updated by subtracting 1 from the content of the register a. In the register b, if the content of the register a is H, it is set to M, and if the content is M, the content is updated. Is done by setting this to L. On the other hand, Ei + Δ
When Ei is smaller than Ecmax, the vehicle speed control unit 10
Acceleration control is performed in which the main shift position is a and the sub shift position is b. That is, first, it is checked whether or not b matches the current sub-shift position B. If they match and it is not necessary to change the sub-shift position, the output port b _{1 is set} to high level, Input port a ₇
The shift motor 20 is rotated in the normal direction until the traveling speed is increased until the input signal is input to the shift motor 20. If b does not match B and the auxiliary shift position needs to be changed, first, the output port b ₄ of the auxiliary shift position is set to low level, the speed increasing instruction lamp 22 is turned on, and the worker is requested to change the auxiliary shift position. Instruct to operate the lever 52 to the speed increasing side. After that, by monitoring the levels of the input ports a ₅ and a ₆ , it is confirmed whether or not the auxiliary shift lever 52 has been operated until the auxiliary shift position becomes b, and if the operation is not performed, the deceleration described above is performed. Output port as in the case of instructions
Set _b6 to high level until the above operation is performed.
Buzzer 24 sounds intermittently at a time interval of T ₁ sec. When it is confirmed that the auxiliary shift lever 52 has been operated and the auxiliary shift position has become b, the vehicle speed control unit 10 turns the output port b ₄ to a high level and turns off the speed increase instruction lamp 22. After that, as described above, the output port b _{1 is set} to the high level so that the main shift position is set to a, and the shift motor 20 is normally rotated. In this way, after the speed increasing control is performed so that the main shift position is set to a and the sub shift position is set to b, the vehicle speed control unit 10
Waits for the predetermined time T ₂ sec, and ends the control operation according to the speed-up control subroutine D.

Vehicle speed control section in acceleration control subroutine D as described above
For the 10 control operations, the current load condition is C in FIG.
A case in the point state will be specifically described as an example. In this case, as described above, the main shift position A is 3, the sub shift position B is M, and the load characteristic curve Fi is selected in the first stage of the speed-up control subroutine D. Then, a = 2, b = H, and B ≠ b, so that the load factor Ei and the load variation ΔEi on the load characteristic curve Fi at the traveling speed adjustment position H2, that is, at the highest speed position are calculated. . As is clear from FIG. 3, Ei + ΔEi at this time is equal to or more than Ecmax, so that a = 1 is set next, and B ≠ b.
Load factor Ei and load variation Δ at travel speed adjustment position H1
Ei is calculated and Ei + ΔEi and Ecmax are compared. As is clear from FIG. 3, Ei + ΔEi at this time is equal to or greater than Ecmax, so that b = M and a = 4 are set next, and B = b, but A ≠ a. Ei at position M4
And ΔEi are calculated. As shown in Fig. 3,
Since Ei + ΔEi is smaller than Ecmax, the vehicle speed control unit 10
By the subsequent operation, the main shift position is set to 4 and the sub shift position is set to M, that is, the operation is performed to realize the traveling speed stage of M4, and the traveling speed is increased. That is, in the speed-up control subroutine D, the load factor of the engine at each traveling speed stage that is higher than the current traveling speed stage is calculated from the current load state, and the vehicle speed control unit 10 outputs the calculation result as described above. Under the condition that the maximum load factor Ecmax is not exceeded, the vehicle operates in order to realize an allowable maximum speed range.

Further, in the above example, E + ΔEi at the traveling speed stage M4
If the value of is equal to or greater than Ecmax, then a = 3 is set, but in this case, B = b and A = a, so the acceleration control subroutine D is followed without increasing the traveling speed. The control operation ends. This is because the current driving speed M3
This is because it is the traveling speed stage on the highest speed side described above, and it is not necessary to perform speed-up control.

Now, in the present embodiment, when the input load factor ε exceeds the maximum limit load factor Ecmax, that is, when deceleration is required, the traveling speed stage is gradually shifted to the deceleration side as in the conventional case. However, this is because Ecmax is set to a high value of 85 to 90%, and at the time of deceleration, it is possible to return to a load factor smaller than the Ecmax by one-step deceleration in the main transmission or the auxiliary transmission. Therefore, it goes without saying that a deceleration control subroutine similar to the acceleration control subroutine D may be provided during deceleration.

Further, in this embodiment, the auxiliary transmission is a manually operated type, but a power shift transmission similar to the main transmission may be used for this, and a hydrostatic transmission may be used for them. Good.

Further, in the present embodiment, the load variation amount ΔEi is added to the load factor Ei obtained from the graph showing the load characteristic, and Ei + ΔEi
When the input load factor ε becomes Ecmax or more due to the short-term fluctuation of the load after speedup, because the acceleration control is performed to realize the traveling speed stage that does not exceed the limit maximum load factor Ecmax. In addition, there is little risk that unnecessary deceleration control is performed due to this.

〔effect〕

As described above in detail, in the device of the present invention, the traveling speed adjustment position where an appropriate load is obtained is obtained from the engine load and the traveling speed adjustment position, and the traveling speed adjustment position of the transmission is changed to realize this. Therefore, even when the load greatly deviates from the appropriate range, the vehicle speed is promptly changed so that the traveling speed becomes appropriate, the work efficiency is improved, and the engine is under the overload condition for a long time. Excellent effects such as not being forced to drive in

[Brief description of drawings]

The drawings show an 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. 3 is a harvester. Graphs showing the relationship between the traveling speed of the machine and the load of the engine, and FIGS. 4 and 5 are flowcharts of vehicle speed control. 3 ... Threshing unit, 4 ... Mowing unit, 9 ... Automatic switch, 10
…… Vehicle speed control unit, 14,15 …… Sub shift switch, 16 …… Shift sensor, 20 …… Shift motor, 30 …… Engine speed control unit, 31 …… Rack position sensor, 51 …… Main shift lever, 52 ... Sub shift lever

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Wataru Nakagawa Wataru Nakagawa 1-32 Chayamachi, Kita-ku, Osaka City, Osaka Prefecture Yanma Agricultural Machinery Co., Ltd. (56) Reference JP-A-60-116008 (JP, A) JP 50-99841 (JP, A)

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. A vehicle speed control device for a harvester that is provided in a harvester and that changes a traveling speed adjustment position of a transmission according to a load of the working unit to control a traveling speed, wherein the engine related to the load of the working unit Load detection means for detecting the load, position detection means for detecting the traveling speed adjustment position, and a relationship between the engine load and the traveling speed at each traveling speed adjustment position, depending on the load state in the working unit. A plurality of load characteristics, which is stored in the form of a plurality of load characteristics, and one of the plurality of load characteristics is selected from the detection results of the load detecting means and the position detecting means, and each of the running characteristics is selected according to the characteristics. A vehicle speed control device for a harvester, comprising: means for calculating an expected engine load at the traveling speed adjustment position and changing the traveling speed adjustment position based on the calculation result.