JPS6361214B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to an automatic vehicle speed control device for a working vehicle equipped with a working machine.

For work vehicles such as tractors, driving on the road for simple transportation, driving by towing a trailer etc. for transportation, driving while towing a flat plate in a rice field,
There are various different work systems, such as driving while rotating a rotary tiller, and driving on four wheels on slopes and uneven terrain.

Depending on the work system, the operator must operate the high and low travel gears to perform the work.

This operation is difficult for beginners because it involves monitoring the position and condition of the work equipment and operating the steering wheel at the same time.

The present invention is configured to automatically change the driving speed according to the engine load.

(b) Conventional technology Conventionally, in part-time 4-wheel drive vehicles, technology has been known that detects the slip condition of the front and rear wheels based on abnormal changes in engine speed and automatically switches between 2-wheel and 4-wheel drive. It is.

For example, Japanese Patent Application Laid-Open No. 122229/1983.

(c) Purpose of the Invention The present invention detects the actual horsepower of the engine with a sensor, and sets the detected actual horsepower to a percentage of the maximum horsepower at the regulator position operated to set the engine speed. By comparing the set horsepower and the set horsepower, the high and low gears are switched.

This allows the regulator position to
This prevents the engine from stalling due to engine overload by switching to the light load side before the actual horsepower R reaches close to 100% horsepower.

Also, in comparing this actual horsepower and set horsepower,
If the transmission is changed frequently due to severe changes in size, the control may enter a hunting state and control stability may be lost.In order to prevent this, the set horsepower is
A belt-shaped dead zone is provided between the two lines as two stages of Woff and set horsepower Won.

(d) Structure of the Invention The object of the present invention is as described above, and next, the structure for achieving the object will be explained.

The actual horsepower R of the engine based on load fluctuations is detected by the position of the adjustment rack 29 that adjusts the discharge amount of the fuel injection pump, and the actual horsepower R and the set horsepower W of the engine at each regulator opening set in the controller C are calculated. In the automatic transmission control device that automatically switches and operates the hydraulic clutches 19 and 20 for high and low speed changes, the set horsepower W is set to change the high and low speed switching solenoid valve 14 from high speed to low speed.
Woff and high/low switching solenoid valve 14 from low speed to high speed
The setting horsepower Won is set to 2, and the Won
> Woff, a dead band is constructed by shifting both set values, and the set horsepower Woff and the set horsepower Won are set as a percentage of the maximum horsepower at each regulator opening.

(E) Embodiment The object and structure of the present invention are as described above. Next, the structure of the embodiment shown in the attached drawings will be explained.

Figure 1 is a plan view of a rotary tiller attached to a tractor, Figure 2 is a diagram showing the arrangement of the panels on the dart board, and Figure 3 is a hydraulic circuit for switching operations based on the results of automatic control. , Figure 4 is a side view of the fuel injection pump device and governor device for detecting actual horsepower, Figure 5 is a control block diagram for actual control, and Figure 6 is a drawing showing the engine characteristic curve. It is.

The overall mechanism of the tractor will be explained with reference to Figure 1.

Reference numeral 1 denotes a bonnet, and an engine is disposed within the bonnet 1. A rotary tiller that is driven by this engine and also serves as a working machine.
It also drives Ro etc. and performs work.

At the rear of the hood, in front of the seat 5, that is, under the steering wheel, is a dash board, and on the instrument panel A of this dash board, an actual horsepower display device 9 and a vehicle speed display device 7, which will be described later, are placed side by side to display the information. be.

Then, depending on the load fluctuation of the actual engine horsepower R, the hydraulic valve of the transmission is automatically switched,
It switches to two-wheel drive with only the rear wheels 4 and 4, or four-wheel drive with the front wheels 3 and 3 added.

FIG. 2 is an enlarged view of the instrument panel of the dash board section.

Reference numeral 10 denotes a sensor lamp that displays detection results from sensors provided in each part of the tractor, and is configured to notify abnormalities by blinking or the like when each part reaches a certain state.

The sensor lamp 10 includes information such as the high beam of the headlights, the use of a thermostart device, the braking of the parking brake, the presence or absence of a deflock state, the drive of the PTO axis,
Flashing lamps display the four-wheel drive status, whether or not charging is in progress, engine lubrication oil pressure, decrease in radiator water volume, clogged air cleaner, decrease in battery fluid level, water separator water level, etc.

A warning lamp 11 for when an abnormality occurs in the sensor of these sensor lamps and a warning lamp 11 for failure of fuel control due to a failure of the electronic governor device are arranged next to it.

Further, 6 is a tilting angle display device for preventing accidents such as overturning when the tractor is working in a tilted state on a slope, 12 is a fuel gauge, and 13 is a cooling water temperature gauge.

In the lower center, an analog display shows the rotation speed of the engine crankshaft with an analog tachometer 7, and below that, the rotation of the PTO shaft is shown with a digital tachometer 8.

And an actual horsepower display device 9 that displays actual horsepower.
is configured as an analog display meter. The analog tachometer 7, which indicates the number of revolutions of the engine, has an inclined part and a horizontal part, and when the engine is rotating at the number of revolutions in the inclined part, it indicates that the engine is not rotating efficiently. In this case, the actual horsepower R is too large, so it is necessary to reduce the gear shift.

And the analog tachometer 7 has scales 7a and 7b.
The bar graph is configured so that it lights up separately and the bar graph expands and contracts, and when scale 7a is the engine rotation, scale 7
In the case of b, the traveling speed is displayed in km/h.

In the present invention, high and low speed changes are performed so that the engine always rotates effectively near the maximum efficiency.

FIG. 4 is a side view of the fuel injection pump portion showing the actual horsepower R sensor of the present invention.

The fuel injection pump 45 is fixed to the side of the engine 23 inside the bonnet 1, and rotates from the engine crankshaft to the fuel pump camshaft 26.
is rotating.

This fuel pump camshaft 26 protrudes into the electronic governor case 31 of the electronic governor device. Similarly, an adjustment rack 29 for adjusting the discharge rate of the fuel injection pump projects into the electronic governor case 31.

The adjustment rack 29 is connected to the control section 33 and the actuator 32 by a pin 28.

The governor gear 27 at the tip of the fuel injection pump camshaft 26 is provided with a convex portion, a magnetic body, etc. for counting the number of revolutions on a governor sensor (not shown), and the governor sensor detects the rotation of the governor gear 27. This is sensed, converted into an electrical value, and transmitted to the control unit 33, which then moves an actuator comprised of a solenoid or the like from side to side.

As a result, when the rotational speed increases, the amount of fuel discharged is reduced to lower the rotational speed, and when the rotational speed becomes low, the amount of fuel discharged is increased to increase the rotational speed.

In this electronic governor device, a stop lever 30 and a regulator lever 40, which are manually operated by an operator, abut the pin 28 from opposite directions.

When the top lever 30 is turned to the left or right in an emergency, the adjustment rack is moved to the low rotation side and fuel injection is stopped, regardless of the position of the actuator 32 or the regulator lever 40.

The regulator lever 40 rotates when the accelerator lever or foot accelerator pedal is depressed, contacts the pin 28, moves the adjustment rack 29 to the high rotation side, and raises the minimum rotation range.

The actual horsepower R of the present invention is determined by converting the left and right movement position of the adjustment rack 29 into rotation using a rack and pinion case 34, and rotating an actual horsepower sensor 35 composed of a rotary encoder or the like to generate a signal as a voltage change. It is.

The value detected by the actual horsepower sensor is displayed on the instrument panel A, and is also fed back to the automatic gear change control device, where it is compared with the set horsepower.

FIG. 3 is a hydraulic circuit diagram of the switching actuator, which performs control operations based on instructions from the control device, contrary to the actual horsepower sensor 35.

Three switching actuators that are actually controlled with respect to changes in the actual horsepower R are shown in FIG. Of the three types of switching devices, the present invention relates to low switching of traveling speed.

The first is the high/low switching section for the travel gear, which is composed of hydraulic clutches 19 and 20, which are the essential parts of the present invention, and the second is the four-wheel drive/two-wheel drive, which is composed of the hydraulic clutch 17. The third is a position control/draft control switching section constituted by a hydraulic clutch 18.

And actually these switching hydraulic clutches 1
9, 20, 17, and 18 are solenoid valves, 14 is a high/low switching solenoid valve, and 16 is a four-wheel drive/
The two-wheel drive switching solenoid valve 15 is a position/draft switching solenoid valve.

In addition, 23 is the engine under the hood, 24
2 is a main clutch device, 25 is a hydraulic pump, 21 is a hydraulic brake pump device, and 22, 22 are hydraulic brake actuators.

The present invention compares the actual horsepower R detected by the actual horsepower sensor 35 with the set horsepower W set in the controller, and switches the high/low switching solenoid valve 14 depending on the magnitude of the comparison.

FIG. 5 is a control flowchart of the present invention,
C is the controller. FIG. 6 shows a characteristic curve map of the engine, and this characteristic curve map is stored in the microcomputer in the controller C.

Further, along this characteristic curve, a band-shaped dead zone surrounded by dotted lines b1 and b2 is set. In the embodiment shown in FIG. 6, this dead zone is set at b1 at the 60% torque point and at b2 at the 40% torque point.

This period becomes a dead zone.

In Figure 6, a1, a2, a3, a4, a
5 is a characteristic curve at each regulator opening, that is, at the accelerator position, and there is a characteristic curve depending on each regulator opening.

Therefore, the rotational position of the regulator lever 40 is also input to the controller C. The rotation speed from the governor sensor is also input to controller C.

Then, in those tables, one map corresponding to the current regulator position in a1...an is selected from the characteristic curve maps in the microcomputer, and the maximum rack position of the adjustment rack 29 in that characteristic map is calculated, Next, from the value of this maximum rack position, the setting horsepower Won at the intersection with the b1 line of the dead band and the adjustment rack position at this position are calculated.
It calculates Wdon.

Also, the set horsepower Woff at the intersection with the b2 line and the adjustment rack position Wdoff at this position are calculated.

On the other hand, the actual horsepower R is determined by changing the movement of the adjustment rack 29 shown in FIG. 4 into rotation by a rack and pinion case 34, and detecting the actual horsepower sensor 35 comprised of a rotary encoder or the like.

Then, the adjustment rack position determined by the above calculation
Easy adjustment of actual horsepower R for Wdon and Wdoff 2
9 position Ract is compared.

If Ract > Wdon, a solenoid valve on signal is issued,
If Ract > Wdoff, a signal is issued to turn off the solenoid valve.

(F) Function of the Invention As described above, the present invention is constructed as described above, and when the tractor is running at high speed with high-low speed change, the slope becomes uneven and overload occurs, the rotation decreases, and the rotation speed decreases by 60% after passing through the dead zone. When entering the load range above the torque point,
When a heavy load is applied to the engine, the high/low switching solenoid valve 14 is turned on to shift to low speed running, and conversely, when the vehicle is going downhill and the torque drops below the 40% torque point, the gear is shifted to high speed.

Similarly, if a load of 60% or more torque is applied while driving in 2-wheel drive, the 4-wheel drive/2-wheel drive switching solenoid valve 16 is switched to switch to 4-wheel drive, and when going downhill, etc., the mode changes to 2-wheel drive. I will return.

Similarly, if the soil changes during position control and the load becomes large and the engine rotation drops and exceeds the 60% torque point, the position/draft switching solenoid valve 1 is activated to protect the engine and agricultural tractor.
5 and switches to draft control, and conversely, when the soil returns to its original state and the load falls below the 40% torque point, it returns to the position controller.

(G) Effects of the Invention Since the present invention is configured as described above, it has the following effects.

First, the engine's actual horsepower R based on load fluctuations is detected, and when the actual horsepower R becomes greater than the setting horsepower W set in the controller C, the high-low gear is switched to low speed. This prevents engine stoppage due to rapid load fluctuations and traction loss due to tire slippage.

Second, when comparing the set horsepower and actual horsepower,
Solenoid valve 1 for switching the set horsepower W from high speed to low speed
Setting horsepower Won to switch between 4 and setting horsepower Woff to switch high-low switching solenoid valve 14 from low speed to high speed.
Since we set two setting values, Won>Woff, and constructed a dead band by shifting both setting values, on the on/off line that occurs when the on and off points match,
This eliminates the hunting situation where the running speed changes many times in a short period of time.

Thirdly, in the conventional technique, JP-A-57-146516, there are 16 balance areas consisting of 4 torque areas in the longitudinal direction and 4 torque areas in the lateral direction. 3. The dead zone is arranged diagonally by discrimination.
Since the area was set, there will be a part where the boundary part becomes a point at the part where the area of □ and the area join at a diagonal position, and in the vicinity of this part, the same state as before without the dead zone will occur. However, in the present invention, the set horsepower Woff
Two lines are drawn depending on the setting horsepower Won,
During that time, a complete dead zone is formed, so a hunting condition where ON and OFF switches do not occur at a single point.

[Brief explanation of drawings]

Figure 1 is a plan view of a rotary tiller attached to an agricultural tractor, Figure 2 is a diagram showing the arrangement of the panels on the dart board, and Figure 3 is a hydraulic circuit for switching operations for switching as a result of automatic control. , Figure 4 is a side view of the fuel injection pump and governor device for detecting actual horsepower, Figure 5 is a control block diagram for actual control, and Figure 6 is a drawing showing special curves of the engine. . R... Actual horsepower, W... Set horsepower, C... Controller, A... Instrument panel, 23... Engine.

Claims (1)

[Claims] 1 Adjustment rack 29 that adjusts the actual horsepower R of the engine based on load fluctuations and the discharge amount of the fuel injection pump
In an automatic shift control device that detects the actual horsepower R and the set horsepower W of the engine at each regulator opening set in the controller C, and automatically switches the hydraulic clutches 19 and 20 for high and low shifting. , the setting horsepower W to switch the high-low switching solenoid valve 14 from high speed to low speed.
Won and high/low switching solenoid valve 14 from low speed to high speed
The setting horsepower Woff is set to 2, and Woff is set to 2.
＞Woff, a dead band is formed by shifting both set values, and the set horsepower Woff and the set horsepower Won are set as a percentage of the maximum horsepower at each regulator opening. .