JP2695645B2 - Motor control device for hydraulically driven vehicle - Google Patents

Description

The present invention relates to a prime mover control device for a hydraulically driven vehicle such as a wheel type hydraulic shovel.

B. Prior Art FIG. 6 shows an example of a traveling hydraulic circuit used in this type of hydraulically driven vehicle.

The direction and flow rate of the hydraulic oil discharged from the hydraulic pump 1 driven by the prime mover 13 is controlled by a hydraulic pilot control valve 2, and is supplied to a hydraulic motor 4 via a counter balance valve 3. A traveling drive shaft (not shown) is connected to the output shaft of the hydraulic motor 4, and the vehicle travels by rotation of the hydraulic motor 4.

The switching direction and stroke amount of the pilot control valve 2 are controlled by the pilot pressure from the pilot hydraulic circuit. The pilot hydraulic circuit converts the pilot hydraulic pump 5 driven by the prime mover 13 and the primary pressure from the hydraulic pump 5 into a secondary pressure proportional to the amount of depression of the pedal 6a, and reduces the stroke amount of the control valve 2. A pilot valve 6 that controls the traveling speed of the vehicle by controlling the vehicle; a slow return valve 7 that follows the pilot valve 6 and delays return oil to the pilot 6; Forward / reverse switching valve 8 for selecting reverse or neutral
And

FIG. 6 shows a state in which the forward / reverse switching valve 8 is in the neutral position (N position) and the pilot valve 6 is not operated. Therefore, the pilot control valve 2 is in the neutral position, The pressurized oil returns to the tank 9 and the vehicle stops. When the forward / reverse switching valve 8 is switched to forward (F position) or reverse (R position) and the pedal 6a of the pilot valve 6 is operated,
The discharge oil from the hydraulic pump 5 reaches the pilot port 2a or 2b of the pilot control valve 2, and the control valve 2 is switched by a stroke amount according to the pilot oil pressure. As a result, the oil discharged from the hydraulic pump 1 is guided to the hydraulic motor 4 via the control valve 2, the pipeline 12a or 12b, and the counter balance valve 3, and the hydraulic motor 4 is driven to drive the vehicle. If the engine speed is constant, the speed of the vehicle depends on the depression amount of the pedal 6a of the pilot valve 6.

When the pedal 6a is released during traveling, the pilot valve 6 shuts off the pressure oil, and the outlet port thereof communicates with the tank 10. As a result, the pressure oil acting on the pilot port 2a or 2b is changed to the forward / reverse switching valve 8, the slow return valve 7, the pilot valve 6
To the tank 10 via. At this time, since the return oil is throttled by the throttle 7a of the slow return valve 7, the pilot control valve 2 is gradually switched to the neutral position. When the pilot control valve 2 returns to the neutral position, the discharge oil of the hydraulic pump 1 returns to the tank 9, and the counter balance valve 3 also switches to the neutral position shown. As a result, a hydraulic brake operates on the hydraulic motor 4.

The make-up valve 11 connected to the hydraulic pump 5 is interposed in the pipelines 12a and 12b of the entrance and exit ports of the hydraulic motor 4, so that when the pressure in the pipeline 12a or 12b decreases, the discharge of the hydraulic pump 5 is reduced. Roads 12a, 12b are replenished, thereby preventing cavitation.

Further, in a vehicle equipped with this type of hydraulic circuit, a fuel lever is provided in a driver's seat, and the rotation speed of the prime mover is controlled according to the operation amount of the fuel lever.

On the other hand, although not shown, a transmission is provided in this type of hydraulically driven traveling device, and the hydraulic motor 4 is driven at any one of a plurality of preset gear ratios selected in advance.
The drive output shaft is decelerated to drive the traveling drive shaft. Usually, two speed ratios for high speed and low speed are set, and one of them is selected as desired.

C. Problems to be Solved by the Invention In the traveling hydraulic circuit described above, the pilot valve 6 is driven by operating the operation pedal 6a, thereby controlling the stroke amount of the control valve 2 to control the vehicle speed. Since the number does not depend on the displacement of the operation pedal 6a, it is necessary to set the engine speed higher in advance by using the fuel lever. Therefore, it is not preferable in terms of fuel, noise, and feeling.

Therefore, if the rotation speed of the prime mover is controlled in accordance with the amount of depression of the operation pedal 6a, the above-described problem is solved. However, if the displacement of the operation pedal 6a and the rotation speed of the prime mover 原 1: 1 correspond to each other, the following problem occurs.

With this configuration, when the pedal 6a is released during traveling, the rotation speed of the prime mover sharply decreases, and the discharge flow rate of the hydraulic pump 1 also sharply decreases. On the other hand, the control valve 2 does not return to the neutral position immediately after the pedal is released due to the action of the slow return valve 7. Therefore, there is a possibility that the pressure oil on the inlet side of the hydraulic motor 4 runs short and cavitation occurs.
For this reason, although the make-up valve 11 is provided, the discharge flow rate of the hydraulic pump 5 used for make-up also decreases, and it becomes difficult to replenish oil sufficient to prevent cavitation. In combination with these actions, if the amount of oil in the pilot circuit for operating the control valve 2 is insufficient and the pedal 6a is depressed immediately after deceleration, a time lag may occur before the control valve 2 is driven.

Providing another hydraulic pump for make-up increases costs and is not preferable in terms of power loss.

Further, it is conceivable that the rotation speed of the prime mover decreases after a delay time from the release of the pedal 6a, but the appropriate delay time differs depending on the level ground, uphill, and downhill. If it is set, the above problems (cavitation and restart time lag) will occur on the downhill, and if the delay time suitable for the downhill is set, it will take time to reduce the engine speed when decelerating on level ground and on the uphill. It is not preferable in terms of fuel consumption, noise, and operation feeling.

SUMMARY OF THE INVENTION It is an object of the present invention to control a prime mover of a hydraulically driven vehicle having improved mileage, noise, and operation feeling without cavitation and restart time lag even when the rotational speed of the prime mover is controlled in accordance with the amount of depression of a travel pedal. It is to provide a device.

D. Means for Solving the Problems The present invention will be described with reference to FIGS. 1 (a) to 1 (c) corresponding to the claims. Elements corresponding to those of the embodiment will be described with the same reference numerals. The present invention relates to a motor 13 and a motor 13
Hydraulic pump 1 driven by
And a control valve for controlling the flow rate and direction of hydraulic oil from a hydraulic pump 1 which is driven by hydraulic oil discharged from the hydraulic pump 4 and drives a traveling drive shaft, and which flows into and out of the hydraulic motor 4 from the hydraulic motor 4. 2 and a control valve operating means 6 for controlling the displacement of the control valve 3 according to the operation amount.

And the motor control device according to the invention of claim 1 is:
As shown in (a), first information detecting means 24 for detecting first information related to the rotational speed of the hydraulic motor 4 and, based on the first information, the first information is A first target engine speed output means 32 that outputs a first target engine speed that takes a value that indicates that the hydraulic motor 4 will not cause cavitation at the time of deceleration. A rotation speed control means 29 for controlling the engine rotation speed of the prime mover 13 so as to attain one target engine rotation speed is provided.

As shown in (b), the prime mover control device according to the fourth aspect of the present invention includes a first information detecting means 24 for detecting first information related to the number of revolutions of the hydraulic motor 4, and the first information Based on the first information, the first information increases when the hydraulic motor rotation speed increases, and the first information takes a value that does not cause cavitation of the hydraulic motor 4 during deceleration.
A first target engine speed output means 32 for outputting the target engine speed, a control valve operation amount detection means 25 for detecting the operation amount of the control valve operation means 6, and a control valve operation amount detected based on the detected control valve operation amount. A third target engine speed output means 36 that outputs a third target engine speed that increases as the control valve operation amount increases; and a third target engine speed output unit 36 that outputs the first target engine speed and the third target engine speed. The first selection means 37 for selecting a larger value among them, and the rotation speed of the prime mover 13
Speed control means 29 for controlling the target engine speed selected by the selection means 37.

As shown in (c), the prime mover control device according to the invention of claim 7 includes a first information detecting means 24 for detecting first information related to the number of revolutions of the hydraulic motor 1, and the first information Based on the first information, the first information increases when the hydraulic motor rotation speed increases, and the first information takes a value that does not cause cavitation of the hydraulic motor 4 during deceleration.
A first target engine speed output means 32 for outputting the target engine speed, a control valve operation amount detection means 25 for detecting the operation amount of the control valve operation means 6, and a control valve operation amount detected based on the detected control valve operation amount. A target value output means 38 for outputting a target value of the first information; and a first value output means 38 for detecting the output target value.
Acceleration information output means 39, 40 for outputting acceleration information corresponding to the difference when the information is larger than the information of the first target engine speed, and outputting the fourth target engine speed by adding the acceleration information of the first target engine speed. Fourth target engine speed output means 41
And a rotation speed control means 29 for controlling the rotation speed of the prime mover 13 to a fourth target engine rotation speed.

E. Function According to the first aspect of the present invention, the first target engine speed output means 32 outputs the first target engine speed based on the first information related to the speed of the traveling hydraulic motor 4. The engine speed is controlled so as to reach the first target engine speed.

According to the fourth aspect of the present invention, the third target engine rotation speed corresponding to the first information relating to the rotation speed of the traveling hydraulic motor 4 and the third target engine speed based on the operation amount of the operation means 6 are provided. The larger value of the third target engine speed outputted from the engine speed output means 36 is selected by the first selecting means 31, and the prime mover speed is controlled to the selected value.

Further, according to the present invention, the target engine speed corresponding to the first information relating to the speed of the traveling hydraulic motor 4 is obtained as described above, and the acceleration information output means 3 is provided.
According to 9,40, the acceleration amount is obtained from the deviation between the first information relating to the rotation speed of the traveling hydraulic motor 4 and the actual value of the first information, and the fourth target engine speed output means is obtained.
At 41, a fourth target engine speed is obtained by adding the acceleration amount to the first target engine speed, and the prime mover speed is controlled to this value.

For this reason, according to the present invention, the prime mover rotation speed does not suddenly decrease at the time of deceleration by the hydraulic brake, a sufficient amount of oil can be supplied to the hydraulic motor 4, and the prime mover rotation speed can be reduced without running cavitation. Can be controlled in relation to the manipulated variable of.

F. Embodiment The prime mover control device according to the present invention has an economy mode,
Although the rotation speed of the prime mover can be controlled by the power mode and the automatic mode, the overall configuration is the same. First, the overall configuration will be described with reference to FIG. A description will be given of a case where this motor control device is used in combination with the traveling hydraulic circuit of FIG.

In FIG. 2 showing the overall configuration of the motor control device according to the embodiment, a transmission 21 is provided on the output shaft of the hydraulic motor 4 shown in FIG. 6, and a differential gearbox 22 is provided on the output shaft of the transmission 21. The differential gearbox 22 is connected to axles 23R and 23L. Rotational speed sensor 24 detects the rotational speed of the output shaft of the transmission 21, and outputs signals corresponding thereto, that is, the vehicle speed V _C. Pedal operation amount sensor 25 detects the depression amount of the pedal 6a of the pilot valve 6, a signal corresponding thereto, i.e., outputs the pedal operation amount N _P.

Reference numeral 26 denotes a gear ratio changeover switch. In this embodiment, it is assumed that the transmission 21 has a high-low gear ratio. When the gear ratio changeover switch 26 is switched to the L position, the gear ratio is low. Output shift information. The fuel lever 27 controls the rotation speed of the prime mover according to the operation amount, and outputs a fuel lever operation amount _NL according to the operation amount. When the forward / reverse selector switch 28 switches the forward / reverse selector valve 8 to the position of F, N, R, respectively, it takes the switching position of F, N, R,
Output forward / backward information corresponding to each position.

Output signals of these sensors and switches are input to the controller 30 and processed as described later. The controller 30 inputs a motor rotation speed command to the pulse motor 29.

The rotation of the pulse motor 29 is transmitted to the prime mover 13 via the lever mechanism 14, and the prime mover 13 rotates at a rotation speed corresponding to the rotation angle of the pulse motor 29.

First Embodiment: Economy Mode Next, the details of the controller 30 according to the first embodiment will be described with reference to FIG.

The function generator 31 outputs a target engine speed Nr ₀ that increases in proportion to the signal based on the fuel lever operation amount _NL . Function generator 32, by the vehicle speed V _C from the rotational speed sensor 24 and transmission information from the transmission ratio change-over switch 26, and outputs the target engine rotational speed Nr _2. The target engine speed Nr ₂ is
It is set in advance so as to satisfy the following conditions.

That 4 cavitation does not occur to the hydraulic motor be run the engine brake release the pedal 6a when a certain vehicle velocity V _C.

Corresponding to the vehicle speed V _C, for example in proportion to increases it.

It Write gear ratio is high is a rotating speed greater than low for a vehicle speed V _C.

The open / close switch 33 is turned off when the forward / reverse selector switch 28 is at the N position, and is turned on when the F / R position is at. The maximum value selection circuit 34 selects the larger one of the target engine speed Nr ₀ and the target engine speed Nr ₂ , and inputs the target engine speed Nr ₁₀₀ as the prime mover speed command to the pulse motor 29.

The operation of the economy mode according to the first embodiment thus configured will be described.

Fuel lever 27 in idle position, forward / reverse selector switch 28
There N position, the gear ratio change-over switch 26 is H position, and the vehicle speed V _C is zero, the prime mover 13 is assumed to rotate at idle speed.

First, the forward / reverse selector switch 28 is switched to the F position to close the open / close switch 33, and then the travel pedal 6a is depressed. In this case, the function generator 32, the vehicle speed V _C is zero, the gear ratio outputs the target engine rotational speed Nr ₂ commensurate with the condition that H.
On the other hand, since the target engine speed Nr ₀ is output from the function generator 31, the target engine speed Nr ₀ and the target engine speed Nr ₂ are input to the maximum value selection circuit 34, and the larger one is The selected engine speed is output as the target engine speed Nr ₁₀₀ . The target engine rotational speed Nr ₁₀₀ is input to the pulse motor 29, the pulse motor 29 takes a rotational angle according to the target engine speed Nr _100. As a result, the prime mover speed is controlled to the target engine speed Nr ₁₀₀ .

On the other hand, when the travel pedal 6a is depressed, the control valve 2 strokes and the hydraulic motor 4 starts rotating as shown in FIG. 6, and the vehicle starts traveling at a certain vehicle speed. Now, vehicle speed
The target engine speed Nr ₂ output from the function generator 32 when _VC is zero is the target engine speed Nr output from the function generator 31 when the fuel lever 27 is at the idle position.
If it is larger than ₀ , the target engine speed Nr ₁₀₀ is
It becomes equal to the target engine speed Nr ₂ from the start of traveling.
The target engine rotational speed Nr ₂ when the vehicle speed becomes larger increases in proportion with the running start. Accordingly, the pulse motor 29 controls the motor 13 so that motor 13 rotates at the target engine speed Nr ₂ determined by the vehicle speed V _C.

As described above, when the travel pedal 6a is depressed, the vehicle travels at a speed dependent on the depression amount, and the prime mover rotation speed increases according to the speed. That the engine rotational speed in this embodiment can be said to be controlled in relation to the traveling pedal operation amount N _P. Therefore, fuel efficiency, noise, and operation feeling are improved.

Here, when traveling at a predetermined speed, the traveling pedal
When 6a is released, the control valve 2 is switched to the neutral position for removal, and the traveling hydraulic motor 4 is operated with a hydraulic brake. At this time, the target engine speed Nr ₂ is maintained by the function generator 32 at a speed at which cavitation does not occur by converting the opening area of the control valve 2 and the make-up amount, thereby preventing cavitation. Further, if the travel pedal 6a is immediately depressed after deceleration without the shortage of the oil amount in the pilot hydraulic circuit, the control valve 2 strokes in response thereto, and the hydraulic motor 4 is immediately accelerated.

Incidentally, by setting the fuel lever operation amount N _L to the maximum, the engine rotational speed is controlled at the target engine speed Nr ₀ from the function generator 31.

(Second embodiment: power mode) A controller according to a second embodiment according to FIG.
30 will be described in detail. The same parts as those in FIG. 3 will be described with the same reference numerals.

The function generators 31 and 32 are exactly the same as in the first embodiment,
Function generator 31 outputs a target engine speed Nr ₀ according to the fuel lever operation amount N _L, the function generator 32 outputs a target engine rotational speed Nr ₂ in accordance with the shift information and the vehicle speed V _C.

The newly added function generator 36, the travel pedal operation amount N _P, and outputs the target engine speed Nr ₁ in proportion to the travel pedal operation amount N _P. Target engine speed N
The r ₁ and the target engine speed Nr ₂ is input to the maximum value selection circuit 37, whichever is larger is outputted from the maximum value selection circuit 37 as the target rotational speed N _10. The target rotational speed N ₁₀ and the target engine speed Nr ₀ is input to the maximum value selection circuit 34, whichever is larger is outputted from the maximum value selection circuit 34 as the target engine speed Nr ₁₀₀ (rotation speed command), The drive of the pulse motor 29 is controlled.

An operation in the power mode according to the second embodiment thus configured will be described.

Fuel lever 27 in idle position, forward / reverse selector switch 28
There N position, the gear ratio change-over switch 26 is H position, and the vehicle speed V _C is zero, the prime mover 13 is assumed to rotate at idle speed.

First, the forward / reverse selector switch 28 is switched to the F position, and the open / close switch 33 is closed. Then, stepping on the traveling pedal 6a when traveling pedal operation amount N _P is a function generator indicating the depression amount
It is input to 36, the function generator 36 outputs the target engine speed Nr ₁ in accordance with the accelerator pedal operation amount N _P. In this case, the function generator 32, in the same manner as described above, and outputs the target engine rotational speed Nr ₂ on the basis of the shift information and the vehicle speed V _C, the target engine speed Nr ₁ and the target engine speed Nr ₂ Is input to the maximum value selection circuit 37. The maximum value selection circuit 37 selects either greater value of the target engine speed Nr ₁ and the target engine speed Nr _2, is input to the maximum value selection circuit 34 through the switch 33 as the target rotational speed N _10. The target engine speed Nr ₀ is also input to the maximum value selection circuit 34,
Is input to the target engine speed Nr ₀ and the pulse motor 29 is selected, whichever is larger as the target engine speed Nr ₁₀₀ of the target revolution speed Nr _10, the pulse motor 29 is driven and controlled. As a result, the prime mover speed is controlled to the target engine speed Nr ₁₀₀ .

On the other hand, when the travel pedal 6a is depressed, the hydraulic motor 4 rotates as described above to start traveling, and a speed dependent on the rotation speed of the prime mover controlled as described above is obtained.

As described above, when the travel pedal 6a is depressed, the vehicle travels at a speed depending on the depression amount, and the rotation speed of the prime mover
It rises according to the amount of depression. In other words, the engine rotational speed in this embodiment can be said to be controlled by the accelerator pedal operation amount N _P.

Here, when traveling at a predetermined speed, the traveling pedal
When 6a is released, the control valve 2 switches to the neutral position, and the traveling hydraulic motor 6 is actuated by a hydraulic brake. In also the target engine speed Nr ₁ output from the function generator 36 when fully release the accelerator pedal 6a is set to the minimum value, the target engine speed Nr ₂ from the function generator 32 in this embodiment Since the value depends on the vehicle speed V _C , cavitation does not occur.
_The target engine speed Nr ₂ is output as ₁₀₀ . Accordingly, the pulse motor 29 has a rotation angle corresponding to the target engine speed Nr ₂ , and the prime mover speed of the prime mover 13 maintains the target engine speed Nr ₂ . That is, the rotation speed of the prime mover in this mode depends on the function generator 31 during acceleration, and depends on the function generator 32 during deceleration. Therefore, as described above, the discharge flow rates of the hydraulic pumps 1 and 5 are sufficient, and cavitation and time lag at the time of restarting are prevented.

In addition, in the case of the power mode, the traveling pedal operation amount N _P accordingly if depresses the accelerator pedal 6a after deceleration is output, the function generator 36 is a target engine speed
Than Nr ₂ can immediately output a large target engine speed Nr _1, if the target engine speed Nr ₁ is supplied to the pulse motor 29, the engine rotational speed is increased immediately in response to the pedal depression amount The feeling is good, and the acceleration performance after deceleration is better than in economy mode.

Also in this embodiment, if the fuel lever operation amount _NL is maximized, the prime mover speed is controlled to the target engine speed Nr ₀ obtained by the function generator 31.

(Third embodiment: automatic mode) A controller according to a third embodiment according to FIG.
30 will be described in detail. The same parts as those in FIG. 3 will be described with the same reference numerals.

The function generators 31 and 32 are exactly the same as in the first embodiment,
Function generator 31 outputs a target engine speed Nr ₀ according to the fuel lever operation amount N _L, the function generator 32 outputs the target engine rotational speed Nr ₂ in accordance with the shift information and the vehicle speed V _C.

The newly added function generator 38, the accelerator pedal operation amount N _P and shift information, and outputs the target vehicle speed V _P which is proportional to the traveling pedal operation amount N _P according to two information. The target vehicle speed V _P is inputted to the deviation circuit 39, the deviation between the vehicle speed V _C [Delta] V
Is taken. The function generator 40 is configured to output the acceleration amount α when the deviation ΔV is equal to or greater than a predetermined positive value, and to reduce the acceleration amount α to zero when the deviation ΔV is less than the predetermined value. Summing point 41 adds the α acceleration of the target engine rotational speed Nr ₂ Toko from the function generator 32 outputs a target rotational speed N _10. The target engine speed Nr ₀ and the target speed N ₁₀ from the function generator 31 are input to the maximum value selection circuit 34,
Any larger value is input to the pulse motor 29 as the target engine revolution speed Nr _100.

The operation of the automatic mode according to the third embodiment having the above-described configuration will be described.

Fuel lever 27 in idle position, forward / reverse selector switch 28
There N position, the gear ratio change-over switch 26 is H position, and the vehicle speed V _C is zero, the prime mover 13 is assumed to rotate at idle speed.

First, the forward / reverse selector switch 28 is switched to the F position, and the open / close switch 33 is closed. Vehicle speed V _C is input to a function generator 32, a function generator 32, the vehicle speed V _C is zero, the gear ratio outputs the target engine rotational speed Nr ₂ commensurate with the condition that H. When stepping on the traveling pedal 6a traveling pedal operation amount N _P corresponding to the amount of depression is input to the function generator 38, the function generator 38
Outputs the target vehicle speed V _P based on the accelerator pedal operation amount N _P input and the shift information, vehicle speed V _C and the target vehicle speed deviation 39
Deviation ΔV of the V _P is taken. The function generator 40 calculates the deviation Δ
The acceleration amount α corresponding to V is output, the acceleration amount α is added to the target engine speed Nr ₂ at the addition point 41, and the target speed N ₁₀ is input to the maximum value selection circuit 34 through the switch 33. The target engine speed Nr ₀ is also input to the maximum value selection circuit 34, and a large value of both inputs is input to the pulse motor 29 as the target engine speed Nr ₁₀₀ , and the rotation angle is controlled,
As a result, the prime mover speed of the prime mover 13 is controlled to the target engine speed Nr ₁₀₀ .

By the above operation, depresses the accelerator pedal 6a, the acceleration amount corresponding to the deviation between the actual vehicle speed V _C and the target vehicle speed V _P which is obtained by the amount of depression α is, the target engine rotational speed Nr ₂ which is obtained by the vehicle speed V _C summed with the target rotational speed N _10, and the
Prime mover revolution speed of the prime mover 13 is controlled to the target rotational speed N _10.

When the travel pedal 6a is completely released, the hydraulic brake is applied to the hydraulic motor 4. At this time, since the deviation device 39 outputs −ΔV, the acceleration amount α of the function generator 40 is zero. However, the target engine speed corresponding the function generator 32 to the vehicle speed V _C Nr ₂ are output, the engine rotational speed is controlled to the target engine speed Nr _2. This target engine speed N
r ₂ is set to a value such that cavitation does not occur even when the hydraulic brake is applied to the hydraulic motor 4 at a certain vehicle speed V _C , as described above, so that when the control valve 2 is switched to the neutral position, A sufficient amount of oil is supplied from the pump 1 to the hydraulic motor 4, and a sufficient amount of oil is replenished from the make-up valve 11. If the travel pedal 6a is depressed again during deceleration and the acceleration amount α (≠ 0) is output from the function generator 40, α is added to the target engine speed Nr ₂ from the function generator 32. The rotation speed of the prime mover 13 increases with good responsiveness, and the feeling and the acceleration performance are improved as described in the second embodiment.

Also in this embodiment, if the fuel lever operation amount _NL is maximized, the prime mover speed is controlled to the target engine speed Nr ₀ output by the function generator 31.

In the configuration of each of the above embodiments, the rotation speed sensor 24 serves as the first information detecting means, the function generator 32 serves as the first target engine speed output means, the pulse motor 29 serves as the rotation speed control means, and the transmission device. Reference numeral 21 denotes a speed change means, a speed ratio changeover switch 26 denotes a speed change information output means, a fuel lever 27 denotes a rotation speed control operating means, a function generator 31 denotes a second target engine speed output means, and a pedal depression amount detection. The sensor 25 controls the control valve operation amount, the function generator 36 controls the third target engine speed output means, the maximum value selection circuit 37 controls the first selection means, and the maximum value selection circuit 34 controls the second selection. The means are respectively configured. Therefore, the target engine rotational speed Nr ₂ is rotational speed first target engine, the target engine speed Nr ₀ number rotates the second target engine, the target engine speed Nr ₁ is the third target engine speed, respectively corresponding target engine speed Nr ₁₀ of the third embodiment corresponds to the target engine rotational speed of the fourth. Also, the vehicle speed V _C is the first related to the motor speed.
Information.

In the above, the vehicle speed was detected by the rotation speed sensor 24,
The number of rotations of the hydraulic motor 4 may be detected and controlled similarly. In this case, the target engine speed Nr ₂
Need not be changed, and the function generators 32 and 38 do not need the shift information.

In the above, the case where the economy mode, the power mode, and the automatic mode are individually set has been described. However, a circuit configuration in which one of the modes is selected by a mode selection switch in which a plurality of modes are set can be easily realized.

Furthermore, although the rotation speed of the prime mover is controlled by the pulse motor, the present invention is not limited to this, and the present invention can be applied to a prime mover equipped with an electronic governor. Further, the traveling hydraulic circuit is not limited to the one shown in FIG. 6, and the present invention can be applied to, for example, one having a make-up circuit of another type or one having no make-up circuit. Although the slow return valve 7 is provided in FIG. 6, the slow return valve may be omitted.

G. Effects of the Invention According to the first aspect of the present invention, a target engine speed is obtained based on the first information related to the speed of the traveling hydraulic motor, and the prime mover speed is controlled to be the target engine speed. I do.

Further, according to the present invention, the larger one of the target engine speed corresponding to the first information relating to the speed of the traveling hydraulic motor and the target engine speed corresponding to the operation amount of the travel operating means. To control the prime mover speed.

Further, according to the invention of claim 7, a target engine speed corresponding to the first information relating to the rotational speed of the traveling hydraulic motor is obtained, and the first information relating to the rotational speed of the traveling hydraulic motor is obtained. An actual value of the first information is detected, an acceleration amount corresponding to a deviation between the first information and the actual value is obtained, and this acceleration amount is added to the target engine speed to obtain the target engine speed. Control the motor speed to a number.

Therefore, according to the present invention, it is possible to control the rotation speed of the prime mover in association with the operation amount of the traveling operation means without causing cavitation at the time of deceleration by the hydraulic brake. Further, the prime mover rotational speed is controlled to a value that is optimal for the rotational speed of the traveling hydraulic motor, thereby improving fuel economy and reducing noise, and improving the operational feeling.

[Brief description of the drawings]

1 (a) to 1 (c) are claims correspondence diagrams. FIG. 2 is a block diagram showing the entire prime mover control device common to the first to third embodiments, and FIGS. 3 to 5 are detailed block diagrams of controllers in the first to third embodiments, respectively. . FIG. 6 is a hydraulic circuit diagram showing an example of a traveling hydraulic circuit to which the present invention is applied. 1: Hydraulic pump, 2: Control valve 3: Counter balance valve 4: Traveling hydraulic motor 5: Pilot hydraulic pump 6: Traveling pilot valve 6a: Traveling pedal 8: Forward / reverse switching valve 11: Makeup valve, 13: Motor 21: Transmission, 24: Revolution speed sensor 25: Pedal depression amount detection sensor 26: Shift switch 27: Fuel lever 28: Forward / reverse switch lever 29: Pulse motor 30: Controller 31, 32, 36, 38, 40: Function Generator 33: open / close switch 34, 37: maximum value selection circuit 39: deviation device, 41: addition point

Claims (9)

(57) [Claims] A motor; a hydraulic pump driven by the motor; a hydraulic motor driven by hydraulic oil discharged from the hydraulic pump to drive a traveling drive shaft; and a hydraulic motor flowing into and from the hydraulic motor. A motor control device for a hydraulically driven vehicle, comprising: a control valve for controlling a flow rate and a direction of pressure oil from the hydraulic pump flowing out; and control valve operating means for controlling a displacement amount of the control valve according to an operation amount. A first information detecting means for detecting first information related to a rotation speed of the hydraulic motor; and, based on the first information, a first information indicating that the hydraulic motor rotation speed is increased. A first target engine speed output that outputs a first target engine speed that increases when the value is shown and takes a value that does not cause cavitation of the hydraulic motor during deceleration. Means a prime mover control device for a hydraulically driven vehicle, characterized by comprising a speed control means for controlling the engine speed of the prime mover such that the rotational speed of the first target engine. 2. The hydraulic drive vehicle further includes a speed changing means for reducing the output of the hydraulic motor at any one of a plurality of speed ratios selected from among a plurality of speed ratios. Further comprising shift information output means for detecting a shift state of the means and outputting shift information corresponding to the gear ratio, wherein the first information is a vehicle speed, and the first information detecting means is a vehicle speed detecting means, The first target engine speed output means takes a value based on the vehicle speed and the speed change information so as to increase as the vehicle speed increases, and take a value such that the hydraulic motor does not generate cavitation during deceleration. 3. The motor control device for a hydraulically driven vehicle according to claim 1, wherein a first target engine speed that becomes higher as the value of the engine speed increases is output. 3. A motor control device, comprising: a rotation speed control operating means operated to control an engine rotation speed; and a second control unit based on an operation state of the rotation speed control operation means.
And a second target engine speed output unit that outputs the target engine speed of the engine, wherein the rotation speed control unit sets the value to a larger one of the first target speed and the second target speed. The motor control device for a hydraulically driven vehicle according to claim 1 or 2, wherein the engine speed of the motor is controlled. 4. A motor, a hydraulic pump driven by the motor, a hydraulic motor driven by hydraulic oil discharged from the hydraulic pump to drive a traveling drive shaft, and a hydraulic motor that flows into and out of the hydraulic motor. A motor control device for a hydraulically driven vehicle, comprising: a control valve for controlling a flow rate and a direction of pressure oil from the hydraulic pump flowing out; and control valve operating means for controlling a displacement amount of the control valve according to an operation amount. A first information detecting means for detecting first information related to a rotation speed of the hydraulic motor; and, based on the first information, a first information indicating that the hydraulic motor rotation speed is increased. A first target engine speed output that outputs a first target engine speed that increases when the value is shown and takes a value that does not cause cavitation of the hydraulic motor during deceleration. Means, a control valve operation amount detection means for detecting an operation amount of the control valve operation means, and a third target engine rotation that increases based on the detected control valve operation amount as the control valve operation amount increases. Third target engine speed output means for outputting a number, first selection means for selecting a larger value among the first target engine speed and the third target engine speed, and the prime mover A motor control device for controlling the number of revolutions of the engine to a target engine speed selected by the first selection means. 5. The hydraulic drive vehicle further includes a speed change means for reducing an output of the hydraulic motor at any one of a plurality of speed ratios selected from among a plurality of speed ratios. Further comprising shift information output means for detecting a shift state of the means and outputting shift information corresponding to the gear ratio, wherein the first information is a vehicle speed, and the first information detecting means is a vehicle speed detecting means, The first target engine speed output means takes a value based on the vehicle speed and the speed change information so as to increase as the vehicle speed increases, and take a value such that the hydraulic motor does not generate cavitation during deceleration. The motor control device for a hydraulically driven vehicle according to claim 4, wherein a first target engine speed set to a higher value is output as the value of the engine speed is larger. 6. A motor control device according to claim 1, wherein said motor control device includes a second control unit for controlling the number of rotations of said engine, and a second control unit for controlling the number of rotations based on an operation state of said first control unit.
A second target engine speed output unit that outputs the target engine speed of the first and second target engine speeds, and a larger one of the second target engine speed and the target engine speed selected by the first selection unit is selected. And a second selecting means for controlling the engine speed of the prime mover to the target engine speed selected by the second selecting means. 6. A motor control device for a hydraulically driven vehicle according to claim 4 or 5. 7. A prime mover, a hydraulic pump driven by the prime mover, a hydraulic motor driven by pressure oil discharged from the hydraulic pump to drive a traveling drive shaft, and a hydraulic motor flowing into and from the hydraulic motor. A motor control device for a hydraulically driven vehicle, comprising: a control valve for controlling a flow rate and a direction of pressure oil from the hydraulic pump flowing out; and control valve operating means for controlling a displacement amount of the control valve according to an operation amount. A first information detecting means for detecting first information related to a rotation speed of the hydraulic motor; and, based on the first information, a first information indicating that the hydraulic motor rotation speed is increased. A first target engine speed output that outputs a first target engine speed that increases when the value is shown and takes a value that does not cause cavitation of the hydraulic motor during deceleration. Means, control valve operation amount detection means for detecting an operation amount of the control valve operation means, and target value output means for outputting a target value of the first information based on the detected control valve operation amount. An acceleration information output means for outputting acceleration information corresponding to the difference when the output target value is larger than the detected first information; and applying the acceleration information to the first target engine speed. In addition, a fourth target engine speed output unit that outputs a fourth target engine speed, and a speed control unit that controls the speed of the prime mover to the fourth target engine speed are provided. A prime mover control device for a hydraulically driven vehicle. 8. The hydraulic drive vehicle further includes a speed change means for reducing the output of the hydraulic motor at any one of a plurality of speed ratios selected from among a plurality of speed ratios. Further comprising shift information output means for detecting a shift state of the means and outputting shift information corresponding to the gear ratio, wherein the first information is a vehicle speed, and the first information detecting means is a vehicle speed detecting means, The first target engine speed output means takes a value based on the vehicle speed and the speed change information so as to increase as the vehicle speed increases, and take a value such that the hydraulic motor does not generate cavitation during deceleration. The motor control device for a hydraulically driven vehicle according to claim 7, wherein a first target engine speed that is set to a higher value as the value of the engine speed increases is output. 9. The engine control device according to claim 1, wherein said engine control means is operated based on an operation state of said engine control means for controlling an engine speed.
A second target engine speed output unit for outputting the target engine speed of the second unit, and a selecting unit for selecting a larger value between the second target engine speed and the fourth target engine speed. 9. The apparatus according to claim 7, wherein the rotation speed control means controls the engine rotation speed of the prime mover to a target engine rotation speed selected by the selection means. Motor control device for hydraulically driven vehicles.