JPH04278843A - Controller for working vehicle - Google Patents

Abstract

PURPOSE:To control the car speed or torque to each constant value by operating an engine revolution speed control part E or transmission control part T according to the variation of the conditions of soil, crops, etc., in the controller for a working vehicle such as tractor. CONSTITUTION:An engine revolution speed control part E is constituted by installing an electronic governor mechanism in an engine, and a transmission control part T having an HST controller H in a speed change device is constituted, and control is performed so that each of car speed and torque is made constant for the variation of load according to the working state, and also in case of car speed control or torque control, control is performed from the transmission control part T, and then control for the engine revolution speed control part E is started.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling the engine rotational speed and speed of a working vehicle such as agricultural machinery so that the vehicle speed and torque become set values as the load changes.

0002

2. Description of the Related Art Conventionally, techniques relating to control devices that respond to changes in the load of a working vehicle have been known. For example, JP-A-54-135102, JP-A-58-
This is similar to the technique described in Japanese Patent No. 20524.

0003

SUMMARY OF THE INVENTION The present invention is equipped with an engine speed control section E and a transmission control section T, and by both of them, the vehicle speed can be controlled to be constant as the load on the work vehicle changes. It controls the torque to a constant level, and in the vehicle speed control and torque control, by setting which of the transmission control section T and the engine rotation speed control section E is controlled first, efficient automatic control can be achieved. It is for controlling. Further, when the transmission control section T is an HST control device H, the swash plate angle during automatic control is configured to be equal to or less than the angle set by the HST operating lever.

0004

[Means for Solving the Problems] The problems to be solved by the present invention are as described above, and next, the means for solving the problems will be explained. That is, the engine speed control section E and the transmission control section T
A work vehicle having a vehicle speed setting device S1 and a vehicle speed detector S2, first controls the transmission control unit T so that the vehicle speed setting value K1 and the vehicle speed detection value K2 are equal,
Next, the engine speed control section E is configured to be controlled. Further, in a work vehicle equipped with an engine speed control section E and a transmission control section T, a torque setting device S3
and a torque detector S4, and first, the transmission control unit T
, and then controls the engine rotation speed control section E. In addition, a vehicle speed setter S1 and a vehicle speed detector S
2 to control the vehicle speed setting value K1 and the vehicle speed detection value K2 to be equal, or a torque setting device S3 and a torque detector S4 are provided so that the torque setting value K3=torque detection value K4. In a work vehicle that controls a transmission control section T, the transmission control section T is an HST control device H, and is configured such that the swash plate angle during automatic control is equal to or less than the angle set by the HST operating lever. This is what I did.

[0005]

[Operation] The operation of the present invention will be explained. A working vehicle such as a tractor works on soil or crops while constantly pulling a working machine, and its load changes from moment to moment due to differences in soil conditions and crop conditions. When the load changes, the vehicle speed decreases or the axle torque increases, but the present invention maintains the engine rotation so that the vehicle speed and torque remain constant throughout the work even if the load changes. It is controlled by a numerical control section E and a transmission control section T. However, by controlling both the engine speed control section E and the transmission control section T, it is possible to maintain a constant vehicle speed and constant torque. , control is performed so that the vehicle speed or torque is constant, and then when the transmission control section T becomes unable to perform control, the engine rotation speed control section E can perform control. Also, the transmission control section T
Separately, an HST operating lever 2 is provided, and the HST operating lever 2 limits the maximum setting angle of the swash plate angle of the HST transmission, making it impossible to control the swash plate angle to rotate beyond that. It is something.

[0006]

[Example] An example of the present invention will be explained. FIG. 1 is a side view of a tractor equipped with a control device for a work vehicle according to the present invention, FIG. 2 is a plan view of the tractor, and FIG. 3 is a transmission case 11.
4 is a side view, FIG. 5 is an enlarged side sectional view of the inside of the transmission case 11, FIG. 6 is a rear sectional view, and FIG. 7 is a plan view of the control operation panel C. It is. An overall side view of the tractor will be explained with reference to FIGS. 1 and 2. FIG. An engine E with an electronic governor mechanism is placed inside the front hood, and the engine E is equipped with an electronic governor mechanism.
A transmission case 11 that is integrated with the clutch hanging is placed on the rear surface. A main clutch is disposed in the clutch housing at the front of the mission case 11, and an HST control device H is disposed at the rear of the mission case 11. The HST control device H is composed of a variable swash plate type hydraulic pump P and a fixed swash plate type hydraulic motor M. A rear axle case 12 is fixed to the rear surface of the fixed swash plate type hydraulic motor M that constitutes the HST control device H. A gear type sub-transmission device and a differential gear device are housed inside the rear axle case 12, and a PTO shaft 13 for driving a working machine is protruded from the rear surface.

The engine speed control section E, which constitutes the main part of the present invention, is constituted by an electronic governor mechanism, and the transmission control section T is constituted by an HST control device H. An HST operating lever 2 is disposed on the right side of a seat S of a tractor, and a neutral switch 3 for the HST operating lever is provided to detect the neutral position of the HST operating lever 2. As shown in claim 3, the HST operating lever 2 is used to set the upper limit of the angle controlled by the swash plate of the HST control device H in the transmission control section T. Further, the neutral position is indicated by a neutral switch 3 for the HST operating lever, and stepless speed change during manual operation is performed by a reverse speed change pedal 14 and a forward speed change pedal 15. Further, as pedals to be operated with the feet, a reverse speed change pedal 14 and a forward speed change pedal 15 are arranged above the right step. A forward/reverse pedal position detection sensor 6 constituted by a rotary encoder is disposed at the pivot shaft of the reverse speed change pedal 14 and the forward speed change pedal 15. A clutch pedal 26 is also arranged above the left step. Furthermore, left and right brake pedals 16L and 16R are arranged above the left step. An HST shift lever 2 and an auxiliary shift lever 8 are disposed on the left side of the seat S, and a PTO shift lever 9 is disposed below the auxiliary shift lever 8. Sub-shift position detection sensors 4a, 4b, and 4c for detecting the shift position of the sub-shift lever 8 are provided in the operating path of the sub-shift lever 8.

[0008] An explanation will be given from an enlarged view of the tractor with reference to FIGS. 3 and 4. The HST operating lever 2 is not configured to mechanically operate the maximum rotation angle of the swash plate from the lever via a link or an arm.
The rotation angle of the swash plate is detected by a rotary encoder and the maximum rotation angle of the swash plate is set. In addition, it detects that the neutral switch 3 for the HST operating lever has rotated to the neutral position,
The swash plate of the HST control device H is electrically controlled to the neutral position by the HST swash plate control device 1. Normally, the depression values of the forward speed change pedal 15 and the reverse speed change pedal 14 are detected by the forward/reverse pedal position detection sensor 6, and the detected values are sent to the HST swash plate control device 1, which causes the HST swash plate control device 1 to extend or retract. The swash plate angle is controlled by A swash plate position detection sensor 7 that detects the rotated position of the swash plate by the HST swash plate control device 1 is configured to be operated in conjunction with the HST swash plate control device 1. In addition, by operating the reverse speed change pedal 14 and the forward speed change pedal 15,
A forward/reverse changeover switch 5 for detecting a switching state is arranged at a position interlocked with a reverse speed change pedal 14 and a forward speed change pedal 15.

Next, a description will be given with reference to FIGS. 5 and 6. An output shaft 19 from a fixed swash plate hydraulic motor M of the HST control device H protrudes inside the rear axle case 12, and a shaft that drives a hydraulic pump P from the engine E is above the fixed swash plate hydraulic motor M. PTO power transmission shaft 17 as is
The PTO power transmission shaft 17 protrudes into the inside of the rear axle case 12, and a loose fitting tube is disposed around the outer periphery of the PTO power transmission shaft 17, into which the gear 21 is loosely fitted. The rotation of the output shaft 19 of the fixed swash plate type hydraulic motor M is transmitted from the gear 20 to the gear 21, and the power is transmitted from the gear 27 to the sub-transmission mechanism 18. The sub-transmission mechanism 18 is provided with speed change shifters 24 and 25, and performs a three-stage sub-speed change. The gear shifter 2
4 and 25 are operated by the aforementioned sub-shift lever 8. A detection rotating body 22 that rotates integrally with the gear 21 is also provided, and the biasing spring 22 operates the vehicle speed detector S2 to detect the vehicle speed. Also torque detector S4
As such, a hydraulic pressure gauge is inserted into the center plate 30 of the HST control device H. The change in pressure within the closed circuit of the HST control device H is detected by substituting the change in torque.

FIG. 7 is a diagram of a control operation panel C, in which a speed range setting switch B controls the vehicle speed to high speed, medium speed, and low speed. Further, an automatic/manual mode changeover switch 28 is provided to change the control mode to automatic/manual. Further, an automatic/manual shift changeover switch 29 is provided for switching the shift from automatic to manual. Further, a vehicle speed setting device S1 and a torque setting device S3 are provided integrally, and by switching the work implement selection switch A, the vehicle speed setting device S1 and the vehicle speed detector S2 can be automatically switched.

FIG. 8 is a side sectional view of the electronic governor mechanism, and FIG. 9 is a front view thereof. The electronic governor mechanism will be explained. Numeral 31 is a fuel injection pump, 33 is a rack actuator, 34 is a position sensor for detecting the position of the rack actuator, 35 is a rotational speed sensor 35, and a separate accelerator position sensor is provided. FIG. 10 is a diagram showing control by the electronic governor mechanism. Figure 8 to Figure 1
0, the engine speed control section E will be explained. Various signals for recognizing the state of the engine are managed by an electronic governor controller, and the electronic governor controller performs control calculations according to a predetermined program and outputs various signals. Regarding the speed fluctuation rate, first, the set value and actual value of the engine speed are recognized, the rack position equivalent to no load is read out, and then the state of the work equipment selection switch A set by the operator is read, and depending on the mode, Calculate the target rack position to be set according to the droop rate map. This target rack position corresponds to the target fuel supply amount for obtaining a predetermined actual value for the set value of the engine speed, and is determined by a calculation formula using the droop coefficient from the detected set value and actual value. . Next, the maximum rack position is read out and compared with the determined target rack position. If the target rack position is smaller than the maximum rack position, a signal is sent from the electronic governor controller to set the target rack position as the actual rack position. Sent. Further, if the target rack position is larger than the maximum rack position, a signal is sent from the electronic governor controller to correct the target rack position to the maximum rack position and to set the actual rack position as the corrected rack position. In this way, the rack position of the fuel pump is automatically set, and constant engine speed control (isochronous control) is performed.

In the case of constant rotation speed control (isochronous control), as shown in FIG. 10, reverse droop control, which is a special control different from droop control, is possible. In other words, if the load suddenly increases when the engine is operating below its peak torque rotation speed, the engine speed will drop significantly or, in extreme cases, the engine will stop. As the pressure decreases, the operating feeling of the tractor deteriorates. Moreover, the result is that the engine is forced to operate in an unreasonable manner. In this example, if the load suddenly increases during work, the set value of the rotational speed is automatically increased to cope with the increase in load by increasing the rotational speed. It also incorporates reverse droop control to prevent a drop in

FIG. 11 shows the relationship between the speed range set by the speed range setting switch B and the vehicle speed. The speed range setting switch B is used to set low speed, medium speed, and high speed, and the engine speed is approximately 900 rpm at low speed, 1800 rpm at medium speed, and 2700 rpm at high speed. has been done. Since the speed that can be changed in each speed range is determined, during automatic control, the speed that can be changed at the time when the rotation angle of the swash plate reaches the maximum is determined from the respective low, medium, and high speed ranges. If the speed range setting switch B goes out of range, the system is configured to automatically move out of the range of the speed range setting switch B and move to the upper or lower speed range.

FIG. 12 shows an electronic governor controller;
It is a drawing showing the entire automatic control mechanism, centering on the central HST controller, HST sub-controller, OK/UFO controller, and loader controller. FIG. 13 is a diagram showing the flow of signals between the central HST controller, electronic governor controller, and HST sub-controller in the case of a vehicle speed control mechanism, and FIG. 14 is a control flowchart diagram of the vehicle speed control mechanism. The vehicle speed control mechanism will be explained with reference to FIGS. 12, 13, and 14. First, select whether the entire tractor is under automatic control or manual control using the automatic/manual gear changeover switch 29 and the automatic/manual mode changeover switch 28.
If the conditions for automatic start are met, then it is determined whether or not the machine is in a working state. In the non-working state, the electronic governor mechanism that constitutes the engine speed control section E is placed in the electronic governor loop control state described above. Next, in the case of a working state, it is determined whether the engine speed is below the peak torque rotation speed at which it is necessary to apply the above-mentioned reverse droop. If the peak torque rotation speed is higher than the peak torque rotation speed, electronic governor isochronous control, which is constant rotation speed control, continues. If the rotation speed is lower than the Pete torque rotation speed, electronic governor reverse droop control is performed.

Next, the vehicle speed detection value K2 of the rotation speed sensor of the output shaft 19 of the HST control device H constituting the vehicle speed detector S2.
Then, the vehicle speed set value K1 is read by the vehicle speed setter S1 provided on the control operation panel C. If the vehicle speed setting value K1 does not equal the vehicle speed detection value K2, it is first determined whether the swash plate of the HST control device H constituting the transmission control section T can be rotated to increase or decrease the speed. If there is a margin in the rotation angle of the swash plate, the swash plate angle is changed to be controlled by the transmission control section T. Next, in the transmission control part T that constitutes the transmission control part T, only when there is no margin in the rotation angle of the swash plate, the engine speed control part E sets the speed range setting switch B described above. It moves up and down through the low, medium, and high speed stages. That is, in FIG. 11, when the engine is in the low-speed range mode, when a command to further increase the speed is issued and the rotation of the swash plate is at its maximum angle and cannot be changed to the speed-increasing side any further, the engine enters the medium-speed range mode for the first time. It is changed by the rotation speed control section E. Also, if the swash plate angle reaches its maximum in the medium speed range mode and cannot be handled, the mode is changed to the high speed range mode. Conversely, in the case of deceleration, if the optimum low speed cannot be obtained at the swash plate angle, the mode is changed from the medium speed range mode to the low speed range mode.

Next, the case of axle torque control will be explained. FIG. 15 is a diagram showing the movement of signals between the central HST controller, electronic governor controller, and HST subcontroller in the case of axle torque control, and FIG. 16 is a flowchart of the axle torque control. This will be explained with reference to FIG. First, the automatic/manual gear changeover switch 29 is turned to
N, it is determined whether automatic control is to be performed, and then automatic control is performed.
It is determined whether the manual mode changeover switch 28 is ON and the engine rotation set by the speed range setting switch B is ON to change to the upper or lower mode. Next, it is determined whether the engine is in a working state, and if it is in a non-working state, the electronic governor mechanism that constitutes the engine speed control section E is switched to droop control. Next, it is determined whether to perform isochronous control or reverse droop control depending on whether the rotational speed exceeds the peak torque point in the working state. Next, the torque detection value K4 of the torque detector S4 constituted by the pressure sensor that detects the hydraulic oil pressure of the HST control device H and converts it into axle torque is read. Next, the torque detection value K4 is read using the torque setting device S3 provided on the control operation panel C. And both of them are torque setting value K3
= torque detection value K4, but if they do not match, first determine whether there is a possibility of changing the swash plate angle of the HST control device H, and decide whether to change the swash plate angle. If there is room, first change the swash plate angle of the HST control device H that constitutes the transmission control section T.
Change the value of torque detector S4. Even if the swash plate angle is changed to a full value, the engine rotational speed control section E
The electronic governor mechanism that constitutes changes the low, medium, and high speeds set by the speed range setting switch B.

Next, claim 3 will be explained with reference to FIG. In FIG. 17, a vehicle speed setter S1 and a vehicle speed detector S2 are provided, and control is performed so that vehicle speed set value K1=vehicle speed detected value K2, or a torque setter S3 and a torque detector S4 are provided.
In a work vehicle that controls a transmission control section T so that torque setting value K3 = torque detection value K4, the transmission control section T is an HST control device H, and the transmission control section T is an HST control device H, It is a flowchart when it is configured so that the plate angle is equal to or less than the angle set by the HST operating lever. normal H
In the ST control device H, the swash plate angle is rotated until it becomes full to control the transmission control section T. However, in the present invention, a separate HST operating lever 2 is provided to control the HST control section T.
The maximum angle controlled by the swash plate is set using the ST operation lever 2, and the swash plate angle is set not to increase beyond that.

For this purpose, the constructed control flowchart shown in FIG. 17 will be explained. That is, first, it is detected whether the neutral position detected by the neutral switch 3 for the HST operating lever is normal or not, and then it is determined whether there is any abnormality in the state of the sensors. Next, it is detected whether swash plate control is to be performed. Next, check whether the automatic/manual mode changeover switch 28 and the automatic/manual transmission changeover switch 29 are in the automatic state, and if they are in the automatic state, the HS
Based on the set position of the T operation lever 2, it is detected whether the swash plate angle detected by the swash plate position detection sensor 7 is large. Next, it is determined whether vehicle speed control or axle torque control is to be performed. When vehicle speed control is to be performed, a vehicle speed control subroutine is entered, and then the flowchart of vehicle speed control shown in FIG. 14 is reached. Next, in the case of axle torque control, the axle torque subroutine is passed through to the axle torque control flowchart of FIG. 16. If it is neither vehicle speed control nor axle torque control, a speed increase subroutine or deceleration subroutine for plowing depth control etc. is reached.

[0019]

[Effects of the Invention] Since the present invention is constructed as described above, the following effects can be achieved. That is, with the configuration as in claim 1, the vehicle speed can be controlled over a wider range than when control is performed only by the engine speed control section E or only by the transmission control section T. For example, it is possible to perform a wide range of tasks that maintain a constant vehicle speed, from transplanting operations that require a relatively high and constant speed to seeding operations that require a low and constant vehicle speed. Furthermore, by controlling the transmission control section T first, it is possible to maintain the set vehicle speed while maintaining the fuel efficiency, noise level, and vibration level of the engine at favorable conditions. Furthermore, the characteristics of the transmission control section T, which has high control responsiveness, can be fully utilized.

[0020] Since the configuration is configured as in claim 2, the torque control range can be made larger than in the case of control by only the engine speed control section E or only the transmission control section T. For example, it is possible to perform a wide range of tasks that maintain a constant torque, from transplanting operations that require relatively low and constant torque to seeding operations that require high and constant torque. Furthermore, by controlling the transmission control section T first, it is possible to maintain the set torque while maintaining the fuel efficiency, noise level, and vibration level of the engine at favorable conditions. Note that if the discharge pressure sensor of the HST control device H is used as the torque detector S4, even if the working machine changes from a plow to a front loader, the same torque detector S4 can be used as is. Also, it is not affected by the responsiveness of the spring, etc.

[0021] Since the structure is configured as in claim 3, even if there is a reduction in load such as a sudden decrease in traction force during plowing during ``vehicle speed control'' or ``torque control,'' the work vehicle is prevented from running out of control. It is possible to do so.

[Brief explanation of the drawing]

FIG. 1 is a side view of a tractor equipped with a control device for a work vehicle according to the present invention.

FIG. 2 is a plan view of the same tractor.

[Figure 3] Mission case 11 and rear axle case 1
FIG. 2 is a plan view of part 2;

FIG. 4 is a side view as well.

FIG. 5 is an enlarged side sectional view of the inside of the mission case 11.

FIG. 6 is a rear sectional view.

FIG. 7 is a plan view of the control operation panel C.

FIG. 8 is a side cross-sectional view of the electronic governor mechanism.

FIG. 9 is a front view as well.

FIG. 10 is a drawing showing control by an electronic governor mechanism.

FIG. 11 shows the relationship between the speed range set by the speed range setting switch B and the vehicle speed.

[Figure 12] Electronic governor controller, central HST controller, HST sub-controller, OK/UF
Focusing on the O controller and loader controller,
It is a drawing showing the entire automatic control mechanism.

FIG. 13 is a diagram showing the signal flow between the central HST controller, electronic governor controller, and HST subcontroller in the case of a vehicle speed control mechanism.

FIG. 14 is a control flowchart of the vehicle speed control mechanism.

[Figure 15] Central HST in case of axle torque control
controller, electronic governor controller, and HST
7 is a diagram showing signal movement between subcontrollers. FIG.

FIG. 16 is a flowchart of axle torque control.

FIG. 17 is equipped with a vehicle speed setter S1 and a vehicle speed detector S2 to control the vehicle speed setting value K1=vehicle speed detected value K2, or is equipped with a torque setter S3 and a torque detector S4, In a work vehicle that controls a transmission control unit T so that torque setting value K3=torque detection value K4, the transmission control unit T is an HST control device H, and the swash plate angle during automatic control is HST. It is a flowchart when it is configured so that the angle is less than or equal to the angle set by the operating lever.

[Explanation of symbols]

E Engine speed control section T Transmission control section 1 HST swash plate control device 2 HST operating lever 3 Neutral switch for HST operating lever 4 Sub-shift position detection sensor 5 Forward/forward detection switch 6 Forward/forward pedal position detection sensor 8 Sub-shift lever 9 PTO gear shift lever

Claims (3)

[Claims] Claim 1: A work vehicle equipped with an engine speed control section E and a transmission control section T, which has a vehicle speed setting device S1 and a vehicle speed detector S2, and has a vehicle speed set value K1 and a vehicle speed detected value K2.
1. A control device for a work vehicle, characterized in that it is configured to first control a transmission control section T, and then control an engine rotation speed control section E so that the numbers are equal. 2. A work vehicle equipped with an engine speed control section E and a transmission control section T, which has a torque setting device S3 and a torque detector S4, and has a torque setting value K3 and a torque detection value K4 equal to each other. A control device for a work vehicle is characterized in that it first controls a transmission control section T, and then controls an engine speed control section E. 3. The vehicle is equipped with a vehicle speed setter S1 and a vehicle speed detector S2, and is controlled so that vehicle speed set value K1=vehicle speed detected value K2, or a torque setter S3 and a torque detector S are provided.
4, which controls a transmission control section T so that a torque setting value K3 and a detected torque value K4 are equal, the transmission control section T being an HST control device H,
A control device for a work vehicle, characterized in that the swash plate angle during automatic control is configured to be equal to or less than the angle set by the HST operating lever.