JPS62162782A - Driver for system including prime mover and hydraulic pump - Google Patents

Abstract

PURPOSE:In a system in which plural variable delivery hydraulic pump are driven by a prime mover, to make it possible to make sufficient use of the output of the prime mover and control the hydraulic pump with excellent responsibility by controlling input horse power for its own hydraulic pump according to the delivery pressure of the other hydraulic pump. CONSTITUTION:Each of variable delivery hydraulic pumps 1, 1' is controlled by a control equipment 18. The control equipment 18 determines the value of control for the number of pump input revolution from the deviation of the actual number of revolution of a prime mover 14 from its target one. Then, the value of control for the pump input for each of the hydraulic pumps 1, 1' is found from the said value of control for the number of pump input revolution and delivery pressure signals P, P' for the other hydraulic pumps 1, 1' and the target delivery quantity of each of the hydraulic pumps 1, 1' is found from pump input torque based on the each value of control for the pump input and the delivery pressure P, P' to control each of the hydraulic pumps 1, 1'.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a motor and hydraulic system in which the discharge amount of a variable displacement hydraulic pump driven by the motor is controlled by a solenoid valve by detecting the tilt angle and pressure. The present invention relates to a drive device for a system including a pump.

<Prior Art> As a drive device for a system including this type of prime mover and a hydraulic pump, there is a conventional drive device described in Japanese Patent Application No. 140449/1982. This device calculates the difference between the target rotation speed set by the accelerator amount of the internal combustion engine and the output rotation speed, that is, the rotation speed deviation, and as this rotation speed deviation increases, the input torque of the hydraulic pump decreases. The target value of the swash plate tilting amount of the hydraulic pump is calculated from the rotation speed deviation and the discharge pressure of the hydraulic pump itself, and the input horsepower of the hydraulic pump is controlled based on the calculation result. It was designed to do this.

<Problems to be solved by the invention> However, in this conventional example, the input horsepower of the hydraulic pump is controlled according to the discharge pressure of the own hydraulic pump, and a large inertial body is used. In working machines, etc., which operate the large inertial body, it is difficult to cope with load fluctuations caused by fluctuations in oil pressure that occur when driving the actuator that operates the large inertial body, and as a result, hunting occurs in the control system, which tends to reduce responsiveness. Conversely, if an attempt is made to lower the gain of the control device in an attempt to prevent knocking, the rotational speed of the prime mover will decrease, making it impossible to fully utilize the output of the prime mover.

The present invention was made in view of the actual situation in the prior art, and its purpose is to develop a motor and hydraulic system that can fully utilize the output of the motor and provide a highly responsive control system. An object of the present invention is to provide a driving device for a system including a pump.

<Means for solving the problem> In order to achieve this object, the present invention provides a first calculation in which a control device calculates a pump input rotation speed control value from a deviation between a target rotation speed and an actual rotation speed of the prime mover. and determining a first pump input control value for the first variable displacement oil field pump from the pump input rotational speed control value obtained by the first calculation means and the discharge pressure of the second variable displacement hydraulic pump. , a second calculation means for calculating a second pump input control value for the @2 variable displacement oil field pump from the pump input rotational speed control value and the discharge pressure of the first variable displacement hydraulic pump; The first variable displacement is determined from the first pump manual torque related to the first variable displacement hydraulic pump obtained based on the first pump input control value obtained by the means and the discharge pressure of the first variable displacement hydraulic pump. While determining the target discharge amount of the hydraulic pump, the second pump input torque related to the second variable displacement hydraulic pump obtained based on the second pump input control value and @2
0 variable displacement hydraulic pump and third calculation means for determining the target discharge amount of the second variable displacement hydraulic pump from the discharge pressure of the second variable displacement hydraulic pump.

<Operation> The present invention is configured as described above, and depending on the deviation between the target rotation speed and the actual rotation speed of the prime mover and the discharge pressure of the variable displacement hydraulic pump other than the own variable displacement hydraulic pump, Since it controls the input horsepower of its own variable displacement hydraulic pump, it increases or decreases its own input torque with respect to the input torque of other pumps, and the total input torque of the entire pump is within the output range of the prime mover. It is possible to control the total input torque in response to the output of the prime mover.

<Example> Hereinafter, a driving device of a system including a prime mover and a hydraulic pump according to the present invention will be explained based on the drawings.

FIG. 1 is a circuit diagram showing the overall structure of an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the structure of a control device provided in the embodiment shown in FIG.

In FIG. 1, 1.1' is 1.1'. a second variable displacement hydraulic pump; 2.2' is a variable displacement mechanism for each of the variable displacement hydraulic pumps 1.1';3.3' is a servo piston that drives the variable displacement mechanism 2.2'; 4. 4'
is a servo cylinder housing a servo piston 3.3'. 4a, 4a', and 4b, 4b' are servo cylinders 4, which are divided by servo pistons 3, 3'IC.
4' left ventricle and right ventricle, respectively.
The cross-sectional area of a and 4a' is the cross-sectional area of right chamber 4b and 4b' d
It is formed larger than. 5 is the servo cylinder 4,
4' is a hydraulic source that supplies pressure oil, and 6 is an oil tank in which hydraulic oil for this circuit is stored.

7.7' is a pipe connecting the hydraulic power source 5 and the left chambers 4a, 4a' of the servo cylinders 4, 4', respectively; 8 is the hydraulic power source 5;
and the right chamber 4b of the servo cylinders 4, 4'.

4 b', 9.9' is a return pipe connecting pipes 7, 7' and oil tank 6, and 10.10' is a pipe connecting hydraulic power source 5 and pipes 7, 7'. A solenoid valve interposed between 1
1.11' is a solenoid valve interposed between line 7.7' and return line 9.9'. These solenoid valves 10.10'
, 11.11' are normally closed solenoid valves (function to return to closed state when energized). A displacement meter 12.12' detects the displacement of the variable displacement mechanism 2.2' of the variable displacement hydraulic pump 1.1' and outputs a discharge amount signal QptQ,' proportional to the amount of displacement. 13.13' is the discharge pipe of the variable displacement hydraulic pump 1.1'.

16.16' is a pressure detector provided in the discharge pipe line 13.13' of the variable displacement hydraulic pump 1, 1', and detects the pressure of the pressure oil that cannot be discharged from the variable displacement hydraulic pump 1.1'. and an electric signal, that is, a discharge pressure signal P.

Output P'. 17.17' is variable displacement hydraulic pump 1
．． A command device for changing the displacement volume of 1′,
A target discharge amount signal QrtQr' is output.

14 is a prime mover, and 20 is a rotation speed detector for detecting the 140 rotation speed of the prime mover.

18 is a control device consisting of a microcomputer;
As shown in the figure, a central processing unit 118a, an output I10 interface 18b, and solenoid valves 101 to 11
．． Amplifiers 18c, 1 connected to 10', 11'
8d, 18e, 18f, a memory 8h for storing a control procedure program, a discharge amount control signal QptQ' output from a displacement meter 12.12', and a pressure detector 16.16.
'The discharge ball force signals P, P' output from the command device 1
7. Target discharge amount signal Q r l output from 17'
A/D converter 8 that converts Q% into a digital signal
g, and a counter 8j that detects pulses corresponding to the rotational speed output from the rotational speed detector 20 and measures the intervals of the pulses.

And the above-mentioned memory 8h and central processing bag #
18a is the target rotation speed N of the prime mover 14.

a first calculation means for calculating a pump input rotation speed control value δ, from the deviation between The first ribbon input control value δ for the first variable displacement oil field pump 1 is determined from the discharge pressure signal P' of the displacement oil field pump 1', and the pump input rotational speed control value δ and the first variable displacement hydraulic bongo are calculated. a second calculation means for calculating a second pump input control value δ' for the second variable displacement hydraulic pump 1' from the discharge pressure signal P; and a first pump input control obtained by the second calculation means. From the first pump input torque T related to the first variable displacement hydraulic pump l obtained based on the value δ and the discharge pressure signal P of the first variable displacement hydraulic pump 1, the first
The target discharge amount Q of the variable displacement hydraulic pump 1 of 3s calculation means for calculating the target discharge amount Q' of the second variable displacement oil field pump 1' from the second pump input torque T' and the discharge pressure signal P' of the second variable displacement hydraulic pump 1'; Please include it.

This control device 18 also receives discharge amount control signals Q and Qp' output from the displacement meters 12 and 12', and a pressure detector 16.
．． Discharge pressure signals P, P/ outputted from 16' and target discharge amount signal Q outputted from command device 1117.17'
,,Q,' and the rotational speed N obtained by measuring the interval of pulses detected by the rotational speed detector 20 with a counter 8j, a variable capacitance is determined based on a control procedure program described later stored in a memory 18hK. Calculate the drive command value for the oil field pump 1.1', and send the command signal Q,,Q,' to the solenoid valve 10°10', 11. 11', the discharge amount signal Q, which is the output of the displacement meter 12.12',
' is the command signal Q0. Using the electro-hydraulic servo, set the position e of the servo piston 3.3' so that it is equal to Q,' (
- It is designed to be controlled by an on-off servo.

This on-off servo is switched when the solenoid valve 10.10' is excited! IBK switching, servo cylinders 4, 4
The left side chambers 4a, 4a' of
The servo pistons 3 and 3' move to the right in FIG. 1 due to the difference in area between the right chambers 4b and 4b' (7).

Further, when the solenoid valves 10, 10' and the solenoid valves 11, 11' are demagnetized and returned to the switching position, the left side chambers 4a, 4a
The oil passage ' is cut off, and the ski pistons 3, 3' are held stationary at that position. In addition, solenoid valve 11.1
1' is excited and switches to switching position B, the left side chamber 4a
, 4a' and the oil tank 6 communicate with each other to form the left side chambers 4a, 4.
The pressure at a' decreases, and the servo pistons 3 and 3' move to the right chamber 4b.

4. Due to the pressure b', it moves to the left in FIG.

Next, the control procedure performed by the control device 18 of the embodiment configured as described above will be explained based on FIG. 3.

First, in step 111, the central processing unit (IT18a) reads the state quantities, that is, the discharge pressure signal P of the pressure detector 16, the discharge pressure signal P' of the pressure detector 16', and the displacement meter 12.
discharge amount control signal Qp of displacement meter 12', /, target discharge amount signal Qr of command device a17, target discharge amount signal Q of command device 117', / and signal of rotation speed detector 20 The prime mover 1 obtained by the counter 18j according to
IA insertion is performed at a rotational speed N of 4.

Then hand Jl! Moving on to 112, the read rotation speed N,
and a preset target rotation speed N (for example, the rated rotation speed of the prime mover 14), the first calculation means calculates ΔN=N − N < 1+, and the result obtained by this equation (1) is A calculation is performed to obtain the pump input rotational speed control value δ,=f(ΔN) from the obtained ΔN. FIG. 4 is an explanatory diagram showing an example of the functional relationship of δ5=fcΔN), and when expressed as a formula, it is K as shown below.

When ΔN - ΔN1, δ, = Of2) - ΔN1≦
When ΔN≦ΔN2, δ, = α fist ΔN+δ N O(31ΔN>ΔN
When δ, = δN2 (4) Next, the process moves to step 113, and the pump input rotation speed control value δ obtained by the first calculating means described above and the second variable displacement hydraulic pumps 1, 1' are calculated.
discharge pressure signal P.

From P', the second calculation means calculates the first pump input control value δ=, lP', δN) and the second pump input control value δ'=J' (P, δN). . FIG. 5 is an explanatory diagram showing an example of these functional relationships, and when expressed as a formula, it becomes 5 below.

When P≦P1, δ=-βYP'+δ1+δN(5) [
However, β=δs/Pt-δ1 and Pl are constants]p>p
When 1, δ=δN (6) Similarly, K.

When P'≦p, / δ'=-β'・P+δ1'+δN
(7) [However, β′=δ1//P! /, δ□' and p, / are constants]P/)P,' (7) To! a'
=aN (8) Next, the process moves to step 114, and the following processing is performed by the third calculation means. First, the minimum input torque 'r of the first variable displacement hydraulic pump 1 is set in advance.
m t n and the first obtained by the second calculation means described above.
From the pump input control value δ, the torque T to be controlled is determined as follows.

T=T, n, ++5 (91 Also, the discharge pressure signal P of the first variable displacement hydraulic pump 1 and (
9) From the torque T of the equation, the first variable displacement hydraulic pump l
The target discharge amount Qp is determined as follows.

Q,,=T/P Similarly for αOO20 variable displacement hydraulic pump 1'.

T/=T1. l, ,'+δlCLυ Q, ,'= T'/P' Q3
is calculated, and the target discharge iQp,' of the second variable displacement hydraulic pump 1' is determined.

In this case, equations α1 and (12) may be divided as they are, but since division i normally requires a long calculation time,
The following approximate method can also be used.

That is, as shown in FIG. 6, for example, a reference hyperbola f0(P)=x/P is stored in advance in the memory 18h, and the values of this hyperbola f, ( Pa)'r Read from memory ish, QPl=fo(”a)×(Tmin+δ) <13
) and calculate by multiplying. In this way, the calculation time is shortened.

Also, as another method, Q9. =T0. ．． /P (The hyperbola of Ixun is stored in the memory 18h, and Q
and transform the coordinate axes of P to Q,.

l It is also possible to obtain an approximate value of .

As described above, the first. Second. After the calculation is performed in the third calculation means, the process moves to step 115.

In this step 115, the target discharge amount QpI of the first variable displacement hydraulic pump 1 obtained in step 114 and the command device (l
! Select the minimum value of the target discharge amount signal Q, 17, and combine it with the command signal Q, to obtain the target discharge amount Q,,' of the second variable displacement hydraulic pump 1' and the target discharge amount of the command device 17'. A process is performed in which the minimum value of the signal Qr' is selected and used as the command signal Q, /.

Next, in step J@116, the discharge amount of the first variable displacement hydraulic pump 1 and the discharge amount of the second variable displacement hydraulic pump 1' are controlled using Qo, Q, and l as target values.

In the embodiment configured as described above, the calculation means @3 operates the first variable displacement hydraulic pump according to the discharge pressure signal P of the first variable displacement oil field pump 1 in response to the first pump input torque δ1. The target discharge amount Q of the second variable displacement hydraulic pump 1' is calculated based on the discharge pressure signal P' of the second variable displacement hydraulic pump 1' with respect to the second pump input torque δ'. , "Y," the first variable displacement hydraulic pump 1 and the second variable displacement hydraulic pump 1' each have a discharge illumination independent of the other pumps.
You can get it.

Further, the second calculation means calculates the second variable displacement hydraulic pump 1.
' from the discharge pressure signal P' of the first variable displacement oil field pump 1.
A first pump input control value δ related to the first variable displacement hydraulic pump 1 is determined, and a second pump input control value δ′ related to the second variable displacement hydraulic pump 1' is determined from the discharge pressure signal P of the first variable displacement hydraulic pump 1. Therefore, it is possible to increase or decrease the input torque of one pump with respect to the input torque of other pumps so that the sum of all input torques becomes the pressure within the output range of the prime mover 14.

Further, based on the pump input rotational speed control value δ obtained by the first calculation means, the second calculation means calculates the first pump input control value δ and the second pump input rotation speed control value δ related to the first variable displacement hydraulic pump l. The second pump input control value δ' for the variable displacement hydraulic pump 1'
Since , the total input torque can be controlled in accordance with the output of the prime mover 14.

For this reason, the output of the prime mover 14 can be fully utilized and a control system with good responsiveness can be obtained.

Furthermore, the functional relationships used in the first calculation means and the second calculation means are not limited to the linear function relationships shown in FIGS. 4 and 5, but can be easily changed as necessary. Desired characteristics can be obtained without changing or adjusting components other than the control device 18.

<Effects of the Invention> Since the drive device of the system including the prime mover and oil field pump of the present invention is configured as described above, it is possible to obtain a control system that can fully utilize the output of the prime mover and has good responsiveness. , and the effects listed below are achieved.

■ Discharge volume can be obtained independently from other variable displacement hydraulic pumps.

■ It is possible to increase or decrease its own input torque with respect to the input torque of other variable displacement hydraulic pumps so that the sum of all input torques is within the range of the output of the prime mover.

■ The total input torque can be controlled according to the output of the prime mover.

■ Desired characteristics can be obtained without changing or adjusting any parts other than the control device.

■ According to the above (■), human torque can be accurately controlled even if the measurement accuracy of pressure detectors, displacement meters, etc. is poor.

(2) Even if the characteristics of the prime mover change due to (2) above, for example due to aging and a decrease in output, the input torque can be controlled in response to the changed characteristics.

■ Input torque can be controlled even when the output characteristics of the prime mover decrease due to thin air, such as at high altitudes.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the overall configuration of an embodiment of a drive system including a prime mover and a hydraulic pump according to the present invention, and FIG. 2 is an explanation showing the configuration of a control device provided in the embodiment shown in FIG. 3 is a flowchart showing the control procedure processed by the control device shown in FIG. 2, and FIG. 4 is a flow chart showing the control procedure processed by the control device shown in FIG. 2. An explanatory diagram showing an example of the relationship, Fig. 5 is an explanatory diagram showing an example of the relationship between the discharge upper force signal of the 0T variable displacement hydraulic pump and the pump input control value set by the control device shown in Fig. 3, @ 6
The figure is a diagram illustrating an approximation method for calculations performed by the third calculation means of the control device shown in FIG. 2. l...First variable displacement hydraulic pump, 1'...
...Second variable displacement hydraulic pump, 10.10', 1
1.11'...Solenoid valve, 12.12'...
... Displacement meter, 14... Prime mover, 16.16'.
...Pressure detector, 17, 17'...Command device, 18...Control device, 18a...
Central processing unit, 18b...I10 interface, 18ct 186w18e, 18f...
...Amplifier, 18g...A/D converter, 18h...Memory, 18j...Counter, Fig. 2 Fig. 4 Fig. 4 5Ni ΔN Fig. 5 Rate () PPrR'P' Figure 6a

Claims (1)

[Claims] (1) A system including one prime mover and at least a first variable displacement hydraulic pump and a second variable displacement hydraulic pump, the input horsepower of the first variable displacement hydraulic pump and the second variable displacement hydraulic pump In the drive device, the control device includes a first calculation means for calculating a pump input rotation speed control value from a deviation between a target rotation speed and an actual rotation speed of the prime mover; A first pump input control value related to the first variable displacement hydraulic pump is determined from the pump input rotational speed control value obtained by the first calculation means and the discharge pressure of the second variable displacement hydraulic pump, and the pump input a second calculation means for calculating a second pump input control value for the second variable displacement hydraulic pump from the rotational speed control value and the discharge pressure of the first variable displacement hydraulic pump; The target of the first variable displacement hydraulic pump is determined from the first pump input torque related to the first variable displacement hydraulic pump obtained based on the first pump input control value and the discharge pressure of the first variable displacement hydraulic pump. A second variable displacement hydraulic pump related to the second variable displacement hydraulic pump obtained based on the second pump input control value while determining the discharge amount.
and third calculating means for calculating a target discharge amount of the second variable displacement hydraulic pump from the pump input torque of the pump and the discharge pressure of the second variable displacement hydraulic pump. system drive device.