JPS59220535A - Controller for operation of wheel loader - Google Patents

Abstract

PURPOSE:To shorten the cycle time by automatically performing a V-shape operation by providing a machanism to vary the distribution ratio of engine output in a working machine and a traveling system. CONSTITUTION:A variable capacity TC14 consisting of a clutch 141 provided between an engine 11 and a change gear 15 and a torque converter (TC) 142, a servo valve 34 to vary the coupling pressure of the clutch 141, a maximum drag force setter 24 to set up the output torque of TC are provided. Also, a sequence controller consisting of a controller 30 to control the valve 34 on each of three operation modes, that is, the first operation mode to completely connect the clutch 141, the second operation mode to convert the output torque of TC into an output torque set by the setter 22, and the third operation mode to give input and output rotation ratios set in the setter 24, a sensor 21 to detect speed- changing time in the change gear 15, and CPU26 to control the device 30 for orderly practising operation modes stored each time of the speed changing time of the change gear 15 with the V-shape operation of the wheel loader is received from the sensor 21 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an operation control device for a wheel loader that distributes engine power to a hydraulic working machine and a traveling system. It relates to an operation control device.

Generally, wheel loaders are used to excavate rock in packets and load them onto dump trucks. Figure 1 shows a series of operation patterns from digging with a wheel loader to loading onto a dump truck. This is the most frequently used operation pattern called V-shape operation.

In order to minimize the working time in this V-shape operation (operations ① to ① indicated by the arrows), the following operation is required.

■ Move the foil loader l forward toward rock 2.

At this time, it is important to run fast, and maximize the power of the driving system.

■ Since it is used for excavation work, it is required that the traction force of the tires is maximum within the range that does not cause the tires to slip.

■ Move the wheel router back from the basic excavation position. At this time, it is important to run fast and maximize the power of the running system.

(2) The driving method is to approach the dump truck 3 without raising the packet, and it is most efficient if the packet is at the vessel height of the dump truck 3 when it reaches the dump truck 3.

In other words, it is necessary to optimally distribute power between the work machine and the travel system.

■ Driving away from the Dump Truck Tsuno 3 while lowering the packet, maximizing the power of the driving system to drive quickly.

By the way, in conventional wheel loaders, the distribution ratio of the engine output between the work equipment and the traveling system is fixed, so if you increase the engine output to increase the output of the work equipment during excavation work during operation, As the K increases, the traction force also increases, resulting in tire slip. In addition, in the case of operation ■, if the power distribution to the work equipment is set small, the packet will not rise to the vessel height when the 1-wheel loader l arrives at the dump truck 3, so the packet will rise to the vessel height. 7') The loading work on the rack 3 has to wait until the work is completed, and on the contrary, the power distribution to the work equipment is set too high. , there was a problem that the running speed was slow.

The present invention solves the above-mentioned problems and provides an operation control device for a wheel loader that can automatically carry out the V-shape operation to shorten the cycle time. With the goal.

According to this invention, a variable capacity torque converter consisting of a clutch and a torque converter is interposed between the engine and the transmission, and by controlling the slip rate of the clutch, the power distribution between the working machine and the traveling system can be varied. a first driving mode in which the slippage of the clutch is reduced to zero and power distribution to the driving system is maximized; and a tire slip mode in which the slippage of the clutch is adjusted appropriately and the output torque of the torque converter is set in advance. A second operation mode in which the output torque is maintained at a maximum output torque within a range in which no
A means for controlling the latch is provided for each of the three operation modes including a second operation mode in which the clutch is controlled so that the clutch is in a state of When detecting the time of gear change, the three operating modes are set to the first, second, first . The control means is sequentially controlled to execute the third and first operation modes in order of KJII, thereby shortening the cycle time of the V-shape operation by 5K.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a block diagram showing an embodiment of the wheel loader operation control device according to the present invention. In the same figure, the output of an engine 11 is connected to a hydraulic pump 13 for driving a lift cylinder 12 of the packet via an appropriate power transmission means.
And, it is a trap to be applied to the hydraulic clutch 141 of the variable capacity torque converter 14.

The hydraulic clutch 141 is slip-controlled by a servo valve 34 (described later), and the driving force from the hydraulic clutch 141 is transferred to the variable capacity torque converter 14.
The torque is applied to the transmission 15 via the torque converter 142, which is another component, and is transmitted to the drive wheels 16 after being appropriately changed in speed.

Output shaft of the above engine 11, torque/core A-11
Speed sensors 17#18 and 19bZ are arranged on the input shaft and output shaft of 42, respectively, to detect the rotational speeds of these and output signals of frequencies corresponding to the speeds, and the detection signals s, 6, a frequency-to-voltage converter (CF/V converter) 20, and a speed sensor 17.
The detection signals 8 and 19 will be described later. pv
(Central processing unit) 26 is added to the input/output circuit 27 .

Further, the transmission 15 is provided with a speed change sensor 21 that detects a time point at which the speed change occurs in the transmission 15.
detection signal (cruise signal that becomes "l#" during gear shifting) Pt
! It is added to the input/output circuit 27 of the 0PU25.

The maximum traction force setting device 22 is configured to determine the driving force (
The set output is converted into a corresponding digital signal DtlC by an analog-to-digital converter (A/D converter) 23 and applied to the input/output circuit 27. The maximum traction force setting device 22 is used to prevent tire slippage, which will be described later. force is set.

FIG. 4 is a graph showing the relationship between vehicle speed and traction force, and the maximum traction force TS is appropriately set by the maximum traction force setting device 22.

The power distribution setting device 24 sets the distribution ratio of the engine output to the work equipment and the traveling system.
Output power/D converter 25 indicating the input/output rotation ratio at 1
The input/output circuit 27 converts it into a digital signal Dr to be compared with
Add to. Furthermore, this power distribution setting device 24 is configured to set the power distribution setting device 24 so that when the packet is approaching the dump truck without raising the packet, when the packet reaches the second dump truck, the height of the raised packet is at the height of the tip of the dump truck. Set the power distribution to the above work equipment and travel system. Further, when setting the power distribution, a signal indicating the input/output rotation ratio of the hydraulic clutch 141, that is, a signal corresponding to the slip rate of the hydraulic clutch 141 is output.

Fig. 3 is a graph showing the relationship between vehicle speed and traction force using the slippage of the hydraulic clutch 141 as a parameter.
If the hydraulic clutch 141's Super S is 100X, then the amount is 0% for the traveling system and 1% for the work machine.
00% power is distributed.

The ROM (read only memory) 28 is the CPU 26
A program showing the control procedure executed by the controller and the relationship between the input shaft rotational speed and the output shaft rotational speed of the torque converter 142 when the output torque is constant are shown for each torque magnitude.・・・・・・
...Ln (see Figure 5)? i' is stored, and the stored contents are read out by the CPU 26. Also, RAM
(Random-access memory) 29 is the CPU 2
6 data storage unit, whose memory contents are 'O
Written and read by A'U26.

Next, the operation of the optr 26 will be explained with reference to the flowchart shown in FIG.

In the V-shave operation (see FIG. 1), operation (2) sets the first gear to F2, fully engages the hydraulic clutch 141, and moves forward at high speed. In operation (2), the gear is set to 'gFl' and the vehicle moves forward at low speed while controlling the hydraulic clutch 141 so as not to exceed the maximum traction force set by the maximum traction force setting device 22. In the operations (2) and (2), the gear position is set to R, the hydraulic clutch 141 is fully engaged, and the vehicle moves backward at high speed. In operation (2), the gear stage is set to F2, and the vehicle moves at high speed while sliding the hydraulic clutch 141 so as to achieve the power distribution set by the power distribution setting device 24.

Now, when ■ shape operation is started, the opυ 26 determines whether the gear stage has been changed from F2 to 71 (from operation ■ to ■) by the signal applied from the shift sensor 21 (judgment 100). inputs a signal B indicating the rotational speed of the output shaft of the engine 11 from the speed sensor 17 (input 101), outputs this signal B1 to the set value register 30 (output 102),
' The set value register 30 (Fig. 2) is the hydraulic clutch 141.
This register 3 is used to set the rotation speed of the output shaft of
The set value set to 0 is applied to the subtracter 32 via the D/A converter 31.

The output signal of the EP/V converter 20, that is, the voltage signal corresponding to the frequency of the detection signal St, is applied to the subtracter 32. Therefore, the subtracter 41
42 outputs a signal indicating the deviation of the input shaft rotational speed from the command value. This deviation signal is applied to the servo valve 34 via an amplifier 33 as a control signal.

When the control signal is positive, the servo valve 34 is switched to the position I to increase the pressing force of the hydraulic cylinder 1411L, that is, the engagement pressure of the hydraulic clutch 141, and when the control signal is negative, it is switched to the position I, and the servo valve 34 is switched to the position I when the control signal is negative. Reduce engagement pressure.

In the above case, the servo valve 34 is controlled to 5 so that the rotational speeds of the speed sensors 17 and 18 match, so the hydraulic clutch 141 is completely connected.

Next, when the first gear is changed from F2 to yl, it is determined whether or not the gear has been changed from Fl to R (from operation ■ to ■) by the signal applied from the shift sensor 21 (
Judgment 200), If it has not been switched, input the signal Dt applied from the maximum traction force setting device 22. Input 201), ROM 28 K Stored songs Is”t~L
n (FIG. 5), selects the curve corresponding to the signal Dt (cJA 202).

Next, input a signal S indicating the output shaft rotation speed of the torque converter 142 from the speed sensor 19 (203).
, 1ltl The input shaft rotational speed of the torque comparator 7142 with the selected curve and signal S, and the output torque constant is determined (process 204). Now, as shown in FIG. 5, the selected curve is Ln. When the signal s1 corresponds to no, the input shaft rotational speed is determined to be n. K like this
The input shaft rotational speed of the torque converter 142 obtained by the calculation is output to the set value register 30 (output 20 g).

In this case, speed sensor? The engagement pressure of the hydraulic clutch 141 is adjusted so that the rotational speeds of the clutches 18 and 19 have the relationship shown in FIG.
That is, the amount of slippage is adjusted as appropriate, and the traction force set by the maximum traction force setting device 22 is maintained.

Next, when the gear is switched from 71 to R, the shift sensor 21 determines whether or not the first gear has been switched from R to IF2 (from operation ■ to ■) based on the signal applied.
Judgment 300), if it has not been switched, input the signal 81 indicating the rotational speed of the output shaft of the engine 11 from the speed sensor 17 in the same way as the input 101 and output 102 described above (input 301), and set this signal B1 to the set value. It is output to the register 30 (output 302).

From this point K, the hydraulic clutch 141 is completely connected.

When the gear is changed from R to F2, the gear changes to F2.
to R (driving ■ to ■) is determined by the signal applied from the shift sensor 21 (determination 40).
0), if it is not switched, the signal s indicating the rotational speed of the output shaft of the engine 11 is sent from the speed sensor 17.
1 shift (input 401), and a signal Dr indicating the input/output rotation ratio in the hydraulic clutch 141 to which the power distribution setting device 24 is also applied. This signal S8 and signal Dr
By multiplying the input shaft rotation speed of the torque converter 142 (the output shaft rotation speed of the hydraulic clutch 141)
(Process 40B) % This determined rotational speed is output to the set value register 30 (Output 404), whereby the 1 hydraulic clutch 141 is controlled to have a constant slip rate, and the engine is applied to the work machine and the traveling system. The output is distributed in the desired proportion.

Further, #CPυ26 applies a packet rise signal (negative signal) to the servo valve 36 via the input/output circuit 27 and the amplifier 35. As a result, the servo valve 36 is switched to position I, and the hydraulic oil is transferred from the hydraulic pump 13 to the check valve 3.
7. Oil chamber XZa of lift cylinder 12 via oil passage 3B
The hydraulic oil in the oil chamber 121) is led to the drain 40 through a 39-ft oil passage. As a result, lift cylinder 12
expands and a packet (not shown) rises. Note that when the dump truck pressure is reached, the packet of rock is thrown into the dump truck by manual operation by the operator.

Next, when the gear is changed from F2 to RK, it is determined whether the first gear has been changed from R to F2 (from operation ■ to ■) or K based on the signal applied from the shift sensor 21 (judgment 500). In this case, similarly to the human power 10L output 102, a signal 51fJI indicating the rotational speed of the output shaft of the engine 11 is sent from the speed sensor 17 (input 501), and this signal s1 is sent to the set value register 3.
0 (output 502).

As a result, the hydraulic clutch 141 is completely connected.

Also, at this time, the aptr 26 applies a packet down signal (positive signal) to the servo valve 36 via the input/output circuit 27 and the amplifier 35. From this K, the servo valve 36 is in position IK.
The hydraulic oil is transferred from the hydraulic pump 13 through the check valve 87 and the oil passage 39 to the oil chamber 12 of the cylinder 12.
1) The hydraulic oil in the oil chamber 12a is guided to the train 41 via the oil passage 38. As a result, the lift cylinder 12 contracts and the packet descends.

When it is confirmed in judgment 500 that the gear stage has been switched from R to F2, a series of V-shape operations (one time) is completed, and the operation returns to the initial operating state of V-shape operation again.

In this way, the K, 0PU 26 detects the gear position by the shift sensor 21 and performs slow operation in V-shape operation.
The hydraulic clutch 1 is determined whether one of the operations is being executed or will be executed, and the hydraulic clutch 1 is set in the optimum operation mode for each operation.
41 is controlled by outputting signals indicating various rotational speeds to the set value register 30. Also, the raising and lowering of packets is automatically controlled by the commands from the 0PU26.

As explained above, according to the present invention, the V of the wheel loader
During shape operation, the slip of the hydraulic clutch is automatically adjusted according to the driving situation, and the engine output is efficiently distributed between the production system and the drive system, reducing the cycle time of V-shape operation. can be achieved. Furthermore, since slipping can be prevented, wear and tear of tires and the like can be prevented.

[Brief explanation of drawings]

Figure 1 is a pattern diagram of V-shave operation of a wheel loader.
Fig. 2 is a block diagram showing an embodiment of the wheel calculator operation control device according to the present invention, Fig. 3 is a graph showing the relationship between vehicle speed and traction force using hydraulic clutch slippage as a parameter, and Fig. 4 is a graph showing the relationship between vehicle speed and traction force using hydraulic clutch slippage as a parameter. A graph showing the relationship between vehicle speed and traction force when the maximum traction force is set. Figure 5 shows the relationship between the input shaft rotation speed and output shaft rotation speed of the torque converter when the output torque is constant, for each torque size. The graph shown in FIG. 6 is a flowchart illustrating the opv control procedure. 11... Engine, 12... Lift cylinder, 13
...Hydraulic pump, 14...Variable capacity torque controller 115...Transmission, 16・φ・Wheel, 17,18
119... Speed sensor, 21-... Speed change sensor, 2
2... Maximum traction force setting device, 24... Power distribution setting device, 26... Central processing unit (oPtr), a o
...Set value register, 34°36...Servo valve, 1
41...Hydraulic clutch, 142...Torque converter

Claims (2)

[Claims] (1) In a wheel loader that distributes engine power to a hydraulic working machine and a traveling system, a variable capacity torque converter consisting of a clutch and a torque converter is interposed between the engine and the transmission; and the engagement pressure of the clutch. a first setting device for setting the output torque of the torque converter, an fs2 setting device for setting the input/output rotation ratio of the clutch, and a first operation mode for completely connecting the clutch. , a second operation mode in which the output torque of the torque converter is set to the output torque set by the setting device of said llX1, and a second operation mode in which the input/output rotation ratio of the clutch is set to the input/output rotation ratio set by the second setting device a control device that controls the engagement pressure changing means of the clutch for each of the three operation modes of No. 3; a detector that detects when the transmission changes gears; , 1st. jlss in the order of the first operation mode, and receives from the detector the time of the gear change of the transmission accompanying the V-shape operation of the wheel loader, and upon accepting this time of shift, the stored operation mode. A wheel loader operation control device comprising: a sequence control device for controlling the control device; (2) The control device detects the rotational speed of the carrot, the input shaft rotational speed, and the output shaft rotational speed of the torque converter, respectively. second and third speed detectors; storage means for storing the relationship between the input shaft rotational speed and the output shaft rotational speed in advance according to the output torque for keeping the output torque of the torque converter constant; 1st
reading means for reading out the input shaft rotational speed at which the output torque becomes constant from the storage means in accordance with the output torque set by the setting device and the output shaft rotational speed detected by the third speed detector; and an arithmetic circuit that multiplies the engine rotational speed detected by the first speed detector and the input/output rotation ratio of the clutch set by the second setting device. The clutch engagement pressure changing means is controlled based on the deviation between the engine rotational speed detected by the first speed detector and the input shaft rotational speed detected by the second speed detector, and the second operation mode is The clutch engagement pressure changing means is controlled based on the deviation between the input shaft rotational speed read by the successive output means and the input shaft rotational speed detected by the second speed detector, and the third operation mode is controlled by the calculation. Operation of the wheel loader according to claim (1), wherein the engagement pressure changing means of the clutch is controlled based on the deviation between the multiplication value calculated by the circuit and the input shaft rotational speed detected by the second speed detector. Control device.