JP3031431B2 - Bulldozer automatic transmission control - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transmission of a bulldozer.
It relates to a control device.

[0002]

2. Description of the Related Art Conventionally, a bulldozer automatic transmission control device includes a torque converter, a transmission, a control valve for controlling a speed stage of the transmission, and a vehicle speed detector (a vehicle speed detecting a transmission output shaft rotation speed to detect a vehicle speed). Placing -equivalent), is composed of a controller for transmitting a signal to the control valve receives a signal from the vehicle speed detector, the vehicle speed is greater than a predetermined shift start vehicle speed controller to the control valve a control signal to To change the speed of the transmission. The speed change is the speed in the transmission.
Multiple hydraulic clutches to set the degree are discharged from the control valve.
It is engaged and released by the pressurized oil.

[0003]

However, according to the above construction, the slippage or slippage of the traveling device during excavation and excavation work.
Vehicle speed when the vehicle speed fluctuates rapidly due to uneven road surface
There therefore increases or decreases frequently and crossed the shift start vehicle speed, Ru made frequent shift-up or shift-down. shift
When shifting up or down, oil in the transmission
The pressure clutch is temporarily released and output to the traveling device
Since the traction force is interrupted, there is a problem that the traction performance is reduced if there is frequent shifts .

[0004] The present invention has been made in view of the above-described problems, even for sudden changes in vehicle speed due to sudden change in the load, frequently without shifting, traction performance deteriorates <br / > It aims to provide a bulldozer automatic transmission control device that does not have any problem.

[0005]

In order to achieve the above object,
The first invention is torque that is attached to the output shaft of the engine
Converter and the output shaft of the torque converter
Transmission that detects the output shaft speed of the transmission
Output shaft speed detector and control to control the speed stage of the transmission
The intersection between the valve and the adjacent speed stage of the vehicle traction curve
The corresponding normal shift start rotational speed is stored in advance and the transmission output
The transmission output shaft speed detected by the shaft speed detector is
Start gear shifting if it exceeds the normal speed shifting start rotation speed.
To output a command to the control valve to shift the transmission
Bulldozer automatic transmission control device with
An engine speed detector for detecting the engine speed; and
Torque converter that detects the output shaft speed of the torque converter
A bar output shaft speed detector is attached, and the controller
A predetermined load fluctuation rate threshold value and a normal shift start rotation speed are determined in advance.
And stores a predetermined sudden load shift start rotation speed
Engine speed and torque converter output shaft speed.
And the calculated traction force of the vehicle
Calculate the load change rate and make the load change rate
Is too large and the output shaft speed of the transmission is under a sudden load
Command to start shifting when it exceeds the start rotation speed
Is output to the control valve. The second invention is the first invention
Based on the invention, detects the vehicle body inclination angle in the front-back direction of the vehicle body
The load change rate is controlled by a controller.
Engine speed and torque conversion
From the traction force of the vehicle calculated based on the
The weight of the vehicle body according to the vehicle body tilt angle from the tilt angle detector
The value obtained by subtracting the component force is calculated by differentiating over time.
Configuration.

[0006]

According to the above construction , the transmission output shaft is normally operated.
The rotation speed exceeds the specified normal speed start rotation speed.
The gearshift command is output from the controller to the control valve
Speeded up. Engine speed and torque converter output shaft
Torque converter speed ratio and torque calculated from rotation speed
For vehicles calculated based on converter performance data
Traction force, that is, load fluctuation by differentiating the load on the vehicle with time
Find the rate. The calculated load change rate is the load change rate stored in advance.
When the value is greater than the threshold value and the transmission output shaft speed is
When the speed is higher than the
The controller outputs a shift command to the control valve to change the speed. During sudden load
The shift start rotation speed is larger than the normal shift start rotation speed
When the load changes suddenly, the vehicle speed increases in a short time.
Shifting starts when the output shaft speed of the transmission is suddenly loaded even if the speed or speed is reduced
The gear does not shift until it becomes higher than the number of revolutions, so
It does not happen frequently. This allows for continuous traction
Output to the traveling device, so the bull with excellent traction characteristics
An automatic transmission control device for the dozer is obtained. Also on slopes
Even in the case of the vehicle body in the front and rear direction of the vehicle body by the inclination angle detector
Detects the tilt angle and calculates the weight of the vehicle weight according to the tilt angle.
Calculate the force component and subtract the calculated component force from the traction force of the vehicle.
Only the excavation load applied to the body from outside
You. In this way, the excavated excavated soil with the effect of the inclination angle removed
Since the load fluctuation rate is calculated based on only the load,
The gear shifting timing when working on the ground
It is determined only by the excavation load. This allows you to
The vehicle is shifted to the speed suitable for excavation
The bulldozer's automatic transmission control device with excellent traction characteristics
can get.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an automatic transmission of a bulldozer according to the present invention.
The control device will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram of an automatic transmission control device, where 1 is an engine,
Reference numeral 2 denotes a torque converter, 3 denotes an engine speed detector, and 4 detects a vehicle body inclination angle in the longitudinal direction of the vehicle body.
That inclination is an angle detector, the vehicle body forward and backward have the 5
Reference numeral 6 denotes a forward / reverse lever for instructing a shift , and reference numeral 6 denotes a torque converter ( hereinafter referred to as a torque converter) output shaft rotation speed detector. 10 is a transmission, 11 is a forward clutch, and 1
2 is a reverse clutch, 13 is a first speed clutch,
14 is a second speed clutch, and 15 is a third speed clutch. Reference numeral 16 denotes a transmission output shaft rotation number detector, which detects a vehicle speed. 17 is the right and left running equipment for the engine power.
The horizontal axis represents device for dispensing the location, 18 towing the traveling device
A sprocket that outputs force . Reference numeral 20 denotes a control valve for controlling a transmission, 21 denotes a reverse clutch valve, 22 denotes a forward clutch valve, 23 denotes a third speed clutch valve,
Reference numeral 24 denotes a second-speed clutch valve, and reference numeral 25 denotes a first-speed clutch valve. Reference numeral 26 denotes a controller, which includes an engine speed detector 3, an inclination angle detector 4, a forward / reverse lever 5, a torque converter output shaft speed detector 6, a transmission output shaft speed detector 16, an electronic modulation Each clutch valve of the valve 20 is connected.

FIG. 2 is a vehicle speed traction curve of a bulldozer. The vertical axis indicates traction, and the horizontal axis indicates vehicle speed. Towing
Force curve 31 is 1st speed, traction curve 32 is 2nd speed, traction
Curve 33 is the third speed. As is clear from the figure, the traction force curves of the respective speed stages intersect at points a and b, and the traction force curve 31 shows the maximum traction force in the low speed range from the point a, and between the points a and b. The traction force curve 32 indicates the maximum traction force, and the traction force curve 33 indicates the maximum traction force at a speed higher than the point b. That is, they correspond to the points a and b.
Set the speed as shift start vehicle speed, vehicle speed shift start vehicle speed
If the gear is changed when the speed becomes larger , the bulldozer always runs with the maximum traction force as indicated by the thick solid line.

Next, an automatic transmission method will be described. In normal driving, before the reverse lever 5 in advance and controller
Rollers 26 send signals to forward clutch valve 22 and first speed clutch valve 25 to start the vehicle in first forward speed. When the vehicle gradually accelerates, the controller 26 receiving the signal from the transmission output shaft rotation speed detector 16 determines that the vehicle speed corresponds to the point a.
When the vehicle speed v1 is reached, a signal is sent to the second speed clutch valve 24 to shift the transmission to the second speed. The shift from the second speed to the third speed is performed in the same procedure when the vehicle speed reaches the vehicle speed v2 corresponding to the point b, and the vehicle is controlled so as to always run with the maximum traction force.

A description will be given of a gear shifting method in the case where the load on the vehicle suddenly changes and the vehicle speed suddenly changes, with reference to the flowchart of FIG. In step 52, the shift lever 5 is operated to move forward or backward. In step 53, the controller 26 determines whether or not the vehicle is moving forward.
In step 4, a control signal is transmitted to the forward clutch valve 22 and the first speed clutch valve 25, and the forward clutch and the first speed clutch are engaged.
If you have to start the vehicle.

When the vehicle starts accelerating, the engine speed is detected in step 55, and the torque converter output shaft speed is detected in step 56. In step 57, the controller 26 calculates and obtains the torque converter speed ratio e = Nt / Ne from the engine speed Ne and the torque converter output shaft speed Nt .
The torque converter speed ratio and the value stored in the controller 26 in advance
The torque converter output shaft torque is calculated based on the torque converter performance data, and the traction force Fm of the vehicle is calculated in consideration of the reduction ratio of the transmission speed stage.

[0012] detection by the inclination angle detector 4 at step 58
Detecting a vehicle body inclination angle θ which issued, controls in step 59
Roller 26 the load F of the vehicle F = Fm-Wsinθ
(W is the vehicle weight).

In step 60, a load change rate α is obtained from the time change rate of the load F. In step 61, the load change rate α is compared with a predetermined load change rate threshold A, and α ≦ A is determined to be YE.
In the case of S, since there is no sudden change in load, step 6
A transmission output shaft rotational speed Nm detected by the transmission rotation speed detector 16 at 2, transmission output shaft speed when the vehicle speed v1
By comparing the normal and the shift start rotation speed n1 is the number Nm,
If Nm.gtoreq.n1 is YES, the program proceeds to a step 63 to shift to the second speed. If Nm ≧ n1 is NO, the first speed is maintained and the process returns to step 55.

If α ≦ A is NO in step 61, there is a sudden load change. Therefore, in step 64, the transmission output shaft rotation speed Nm and the rapid load shift start rotation speed n2 described later are compared with each other. Compare. In the case of a sudden load change, the vehicle speed may repeatedly accelerate and decelerate in a short time. In the case of a sudden load change, the vehicle speed may repeatedly accelerate and decelerate in a short time. In this case, when the vehicle speed reaches n2 and the vehicle shifts to the second speed, the operation of decelerating and shifting to the first speed is frequently repeated immediately after that, and the towing performance deteriorates.

In order to prevent this, start shifting under sudden load.
Given the value of the rotational speed n2 than normal shift start rotation speeds n1
Speed only is set to have a size value. For example, at the time of shifting from the first forward speed to the second forward speed, the normal speed shift start rotation speed n1
Sets the sudden load shift start rotation speed n2 to 606 rpm with respect to 570 rpm. That is, if the shift start speed is V1
From the driving performance curve shown in FIG. V
3 is a vehicle speed corresponding to n2. And step 64
If Nm≥n2 is YES, the program proceeds to step 65 to shift to the second speed. In the case of NO, the first speed is maintained and step 55 is executed.
Return to the processing of. In this way, the vehicle speed reaches V3 even if the load suddenly fluctuates and the vehicle speed repeats some acceleration and deceleration.
Otherwise, the transmission will not shift from the first gear to the second gear, so frequent shifts will not be performed and traction performance will not be reduced.

As described above, the shift from the first forward speed to the second forward speed is performed.
In the case of the top-down, the second forward speed to the third forward speed
The same shift processing is performed in the case of upshifting to. A similar shift process is performed in the case of reverse travel.

[0017]

As described in detail above, during normal times,
The output shaft speed of the machine is higher than the specified normal speed start rotation speed.
The gearshift command is output from the controller to the control valve
The speed is changed. Engine speed, torque converter
Vehicle calculated based on output shaft speed and vehicle body inclination angle
Load fluctuation rate, which is the time derivative of the load on the body, is stored in advance.
Is greater than the specified load regulation threshold and the transmission output
Shaft rotation speed is greater than predetermined sudden load shift start rotation speed
Sometimes the controller outputs a shift command to the control valve and shifts
I do. The speed change start rotation speed under sudden load is the normal speed change start rotation speed.
It has a value larger than the number, and when the load changes suddenly, the vehicle speed
The transmission output shaft speed is suddenly high even when accelerating or decelerating in a short time.
Do not shift gears until it exceeds the load rotation start rotation speed.
Therefore, shifting does not occur frequently. This allows
Since the traction force is continuously output to the traveling device, the traction force
An automatic transmission control device for a bulldozer having excellent characteristics can be obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an automatic transmission according to the present invention.

FIG. 2 is a running performance curve of a bulldozer.

FIG. 3 is a flowchart of an automatic shift.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Engine 2 Torque converter 3 Engine speed detector 4 Tilt angle detector 5 Forward / reverse lever 6 Torque converter output shaft speed detector 10 Transmission 16 Transmission output shaft speed detector 20 Electronic control modulation valve 26 Controller

Claims (2)

(57) [Claims] An engine (1) is attached to an output shaft.
Torque converter (2) and transmission mounted on output shaft of torque converter (2)
(10) and a transmission output shaft for detecting the output shaft rotation speed (Nm) of the transmission (10)
The speed detector (16) and the control that controls the speed stage of the transmission (10)
For each intersection (a) between the control valve (21-25) and the adjacent speed stage of the vehicle traction curve,
The corresponding normal shift start rotational speed (n1) is stored in advance and the transmission
Transmission output shaft detected by output shaft speed detector (16)
The rotation speed (Nm) is larger than the normal speed change start rotation speed (n1).
Command to start shifting is output to the control valve (21-25).
Bulldozer having a controller (26) for shifting the speed changer (10)
In the automatic transmission control device of the user, an engine speed detector that detects the speed of the engine (1)
Detects the output shaft speed (Nt) of (3) and torque converter (2)
A torque converter output shaft speed detector (6)
Then, the controller (26) sets a predetermined load variation rate threshold (A) and
And a sudden load that is greater than the normal speed change start rotation speed (n1)
The speed change start rotation speed (n2) is stored, and the engine speed (Ne) and
And the torque converter output shaft speed (Nt).
Load fluctuation rate by differentiating the traction force (Fm) of the vehicle
(α) is calculated, and the load change rate (α) is set to a predetermined load change rate threshold.
(A) and the transmission output shaft speed (Nm)
Shifting is performed when the speed is higher than the shift start rotation speed (n2) during sudden load
It outputs the start command to the control valve (21-25).
Bulldozer automatic transmission control device. 2. The automatic shift control of a bulldozer according to claim 1.
In the control device, the tilt angle for detecting the vehicle body tilt angle (θ) in the front-rear direction of the vehicle body
A detector (4) is attached, and the load variation rate (α) is
Engine speed (Ne) and torque converter output shaft speed (N
t) from the vehicle's tractive force (Fm) calculated based on
Body weight (W) according to body tilt angle (θ) from detector (4)
Calculate by differentiating the value obtained by subtracting the component force of
Bulldozer automatic shift control instrumentation, characterized in that the
Place.