JPH04175572A - Setting method and device for prime mover target revolving speed characteristic of oil pressure drive device - Google Patents

Abstract

PURPOSE:To perform rewriting of the target revolving speed characteristic simply and shortly by sensing the actual revolving speed of a prime mover under certain conditions, correcting the basic target revolving speed characteristic in memory with the actual revolving speed obtained, and setting the target revolving speed characteristic. CONSTITUTION:A controller 80 comprises a function generator 181, into which the accel, pedal 10 stamping amount Xp is intered and which emits an applicable function f(Xp), and a factor apparatus 182 into which the actual revolving speed Na sensed by a revolving speed sensor 11 is entered and which updates the factor (a) according to the actual revolving speed Na in conformity to on signal of a rewrite switch 13. The outputs of these function generator 181 and factor apparatus 182 are added together by an adding device 183 to determine the target revolving speed Nr, and its deviation Nd from the actual revolving speed Na is calculated by a deviation device 184, and the deviation obtained Nd is integrated by an integrator 185 to emit a discharge capacity control signal K. Setting of the target revolving speed characteristic is made by turning the prime mover 1 in idleing, i.e., releasing the accel, pedal 10, followed by turning-on of the switch 13.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a method and apparatus for setting prime mover target rotation speed characteristics of a hydraulic drive system in which a variable displacement hydraulic pump and a hydraulic motor are connected in a closed circuit.

B. Conventional technology Figure 6 shows the results of the 8th Aachen Hydraulic Technology Joint Discussion (1988).
FIG. 2 is a diagram illustrating the prior art disclosed in Volume 2 of a collection of papers entitled "Electronic Control and Adjustment in Hydraulic Transmission Vehicles" (March 15-17, 2013).

In the figure, a hydraulic motor 5 is connected in a closed circuit to a variable displacement hydraulic pump 2 driven by a prime mover 1 via main lines 3 and 4. A controller 8 is connected to an electric regulator 6 that controls the discharge capacity of the variable displacement hydraulic pump 2 via a forward/backward switch 7, and the discharge capacity of the variable displacement hydraulic pump 2 is controlled by a discharge capacity control signal from the controller 8. controlled.

An accelerator pedal 10 is connected to the throttle lever 1a of the prime mover 1 via a cable 9, and the number of rotations of the prime mover is adjusted depending on the amount of depression of the accelerator pedal 10. The actual rotation speed Na of the prime mover is detected by the rotation speed sensor 11,
The amount of depression Xp of the accelerator pedal 10 is detected by a potentiometer 12 .

The controller 8 includes a function generator 81 that reads out the target rotation speed Nr based on the depression amount signal Xp from the potentiometer 12, an operational amplifier 82 that outputs the deviation Nd between the actual rotation speed signal Na and the target rotation speed Nr, and an operational amplifier 82 that outputs the deviation Nd between the actual rotation speed signal Na and the target rotation speed Nr. The output K from the integrator 83 is input to the regulator 8 via the forward/reverse switch 7, and the discharge capacity of the variable displacement hydraulic pump 2 is controlled. Although an example using only the integrator 83 is shown here, it may be configured to perform, for example, well-known PID control. When the forward/reverse switch 7 is in the F position, pressure oil is discharged to the pipe line 3 side, when it is in the R position, pressure oil is discharged to the pipe line 4 side, and when it is in the N position, the variable displacement hydraulic pump 2 is in the neutral state. position and no pressure oil is discharged. L3 is
This is a switch that is turned on when setting the target rotation speed characteristic of the function generator 81, as will be described later.

Here, the input-output characteristics of the function generator 81, that is,
The characteristics of the target rotational speed Nr with respect to the accelerator depression amount Xp are set as follows.

When the switch 13 is operated, the controller 8 is switched to a setting mode for the prime mover target rotation speed characteristics.

In this state, the operator slowly depresses the accelerator pedal 10 to the full throttle position, and the characteristic of the prime mover rotational speed Na relative to the depressing amount Xp during that time is input into the controller 8. This characteristic is indicated by the broken line a in FIG. Throttle position "1"
”, the prime mover rotational speed is Nmax. Then, a characteristic is set that connects the point where the rotational speed Nmax at the full throttle position is reduced, for example, by 20%, and the point of the idle rotational speed Ni at the non-operating position "0", and this characteristic is used to Set as a numerical property.

According to such a hydraulic drive device, the discharge capacity of the hydraulic pump 2 is adjusted in accordance with the amount of depression of the accelerator pedal 9, and overload of the prime mover 1 is prevented, thereby preventing engine stalling.

Problems to be Solved by the C0 Invention However, such conventional devices have the following problems.

(1) When setting target rotation speed characteristics, it takes several tens of seconds to more than a minute to rewrite the previously set characteristics.

(2) The work is interrupted when setting the target rotation speed, and it is difficult to rewrite it during the period from startup to warm-up.

(3) It is necessary to operate the accelerator pedal 9 quasi-statically, which requires skill and is complicated.

An object of the present invention is to provide a method and apparatus for setting a target rotation speed of a prime mover for a hydraulic drive device, which allows rewriting target rotation speed characteristics with simple operations and in a short time.

The present invention will be explained in conjunction with FIG. 1, which is an embodiment of means for solving the D0 problem. A hydraulic motor 5 connected in a closed circuit to the pump 2, a command means 10 for commanding the rotation speed of the prime mover 1, a detection means 11 for detecting the actual rotation speed of the prime mover 1, and a hydraulic motor 5 connected in a closed circuit to the pump 2, a command means 10 for commanding the rotation speed of the prime mover 1, and a detection means 11 for detecting the actual rotation speed of the prime mover 1, according to a preset target rotation speed characteristic. Discharge capacity control means that controls the discharge capacity of the variable displacement hydraulic pump 2 according to the deviation Nd between the target rotation speed Nr read based on the command value XP of the command means 10 and the detected actual engine rotation speed Na. 80 respectively.

In the method invention, the actual rotation speed of the prime mover 1 is detected under predetermined conditions, and the basic target rotation speed characteristic stored in advance is corrected by the detected actual rotation speed to set the target rotation speed characteristic. This achieves the above objective.

Further, in the device invention, a storage means 81 for storing a basic target rotation speed characteristic, and a basic target rotation speed characteristic stored in advance in this storage means 81 are corrected by an actual rotation speed detected under predetermined conditions. By providing setting means 82 and 83 for setting the target rotation speed characteristics, the above-mentioned object is achieved.

81 action The actual rotational speed of the prime mover 1 is detected under predetermined conditions. The basic target rotation speed characteristic stored in advance is corrected by the detected actual rotation speed, and the target rotation speed characteristic is set.

F. Embodiment An embodiment of a method and apparatus for setting a target rotational speed of a prime mover for a hydraulically driven vehicle according to the present invention will be explained with reference to FIGS. 1 and 2. FIG.

FIG. 1 is an overall configuration diagram of a prime mover target rotation speed setting device for a hydraulically driven vehicle. Elements similar to those in FIG. 6 will be described with the same reference numerals, but the difference from the device in FIG. 6 is the controller 8, so the explanation will focus on the controller.

Reference numeral 80 denotes a controller of this embodiment, which receives a function generator 181 that generates a function f (Xp) by inputting the amount of depression Xp of the accelerator pedal 10, and an actual rotational speed Na detected by the rotational speed sensor 11. In response to the ON signal of the rewrite switch 13 (rewrite signal Rev), the actual rotation speed N
a coefficient unit 182 that updates the coefficient α according to a; an adder 183 that adds the output of the function generator 181 and the output of the coefficient unit 182 to output a target rotation speed Nr; Deviation device 18 that calculates the deviation Nd from the rotation speed Na
4, and an integrator 185 that integrates the deviation Nd and outputs a discharge volume control signal K.

Note that although an example using only the integrator 185 is shown here, it may be configured to perform well-known PID control, for example.

As can be seen from Fig. 1, the target rotation speed Nr is a function f (X
p) and the output α of the coefficient unit 182. function f
(Xp) is called the basic target rotational speed characteristic, and is set in advance for each prime mover based on the specification values of the prime mover 1 and experiments in the average usage environment of several prime movers, and is indicated by the broken line A in FIG. On the other hand, the coefficient α is expressed as the intercept N■ of the prime mover rotational speed axis in FIG. Characteristic A is moved in parallel and a new target rotation speed characteristic is set.

Here, the setting operation of the target rotation speed characteristic will be explained.

Unlike the conventional example, there is no need to slowly depress the accelerator pedal and collect the rotation speed characteristics with respect to the amount of accelerator pedal depression, and the prime mover 1 is kept in an idle state.

That is, the setting can be made simply by releasing the accelerator pedal 10 and turning on the switch 13. When the switch 13 is turned on, the coefficient multiplier 182 updates and holds the currently stored coefficient α to the actual rotation speed Na (idle rotation speed) input at that time. Therefore, the target rotation speed Nr is determined by the adder 183 as the sum of the function f (Xp) and the coefficient α, and is determined by the characteristic obtained by translating the basic target rotation speed characteristic A as shown in the characteristic diagrams A' and A'' in FIG. It is expressed as

The accelerator pedal 10 and the throttle control correct the predetermined basic target rotation speed characteristics based on the idle rotation speed. 1, and also compensates for the decrease in prime mover output at high altitudes and due to aging, but the former output fluctuation is
The output torque curve 4IC in FIG. 3 moves in parallel as shown by the solid lines A' and A' in FIG.
Since the parallel movement occurs as shown in ", it is sufficient to deal with the parallel movement of the basic target rotational speed characteristic using the above-mentioned coefficient α.

The general operation of such a device will be explained assuming that the forward/reverse selector switch 7 is in the F position.

When the accelerator pedal 10 is not operated (Xp=O), both the actual rotation speed NCL and the target rotation speed Nr are the idle rotation speed Ni. At this time, the deviation Nd does not occur,
Since the discharge volume control signal K to the variable displacement hydraulic pump 2 does not change, the discharge volume of the variable displacement hydraulic pump 2 remains zero. When the hydraulic pump 2 tries to discharge pressure oil in this state, the actual rotation speed Na becomes lower than the target rotation speed Nr, so the deviation Nd becomes negative, the discharge volume control signal K decreases, and the discharge volume of the hydraulic pump 2 is decreased. As a result, the discharge amount becomes zero.Next, the accelerator pedal 10 is depressed to the maximum (Xp=1
) sometimes works like this: The relationship between the prime mover rotational speed and the output torque in this case is shown by the characteristic diagram in FIG. When the load is light, for example at point E, the prime mover rotational speed does not decrease much, so N a > N r and the discharge capacity increases to the maximum discharge capacity. In this way, by depressing the accelerator pedal 10 between 0 and 1, the pump discharge capacity changes between 0 and the maximum, and the accelerator pedal 10 changes between 0 and the maximum.
It becomes possible to control the speed of the load using zero.

Furthermore, when the load increases and the motor output torque increases with the amount of depression of the accelerator pedal 10 being Xp=1,
The rotational speed of the prime mover decreases as indicated by arrow F in FIG.

When the load increases further and reaches point G, for example, and the prime mover rotation speed Na falls below the target rotation speed Nr, the deviation Nd becomes negative, the discharge volume control signal K decreases, and the discharge volume of the variable displacement hydraulic pump 2 is reduced. let Since the pump absorption torque decreases as the discharge capacity decreases, the prime mover torque is prevented from increasing and the prime mover rotational speed is maintained at approximately point G. In addition, 20% of the maximum engine rotation speed Nmax explained in the conventional technology
The drop point is the rotational speed corresponding to point G in FIG. Furthermore, in FIG. 4, a dotted line H indicates pump absorption torque.

FIG. 5 shows another circuit for generating the rewriting signal Rew of the coefficient multiplier 182.

In FIG. 5(a), the rewrite signal Rev is output when the engine is at idle speed, the work implement control lever is in the neutral position, and the rewrite switch 13 is on. Therefore, a detector 21 that detects that the operating lever is in the neutral state, an idle signal generator 22, and an AND gate 23 that takes the logical product of the signal of the detector 21, the idle signal, and the on signal of the switch 13 are connected. Be prepared. Here, the idle signal generator 22 is configured to be output after a predetermined delay time has elapsed after detecting that the accelerator pedal 10 has been released.

According to such an embodiment, there is no fear that the coefficient lχ may be rewritten due to the operator's carelessness when the work equipment is being operated even when it is not idling, and the target rotation speed characteristic setting can be changed. Improved reliability. Note that the working machine refers to, for example, a wheel loader or a hydraulic excavator packet.

FIG. 5(b) shows yet another generation circuit for the rewriting signal Rev.

When the signals are output from the detector 21 and the idle signal generator 22, the rewrite signal Rev is input to the coefficient unit 182 through the ant gate 23. According to this embodiment, the coefficient α can be rewritten during no-load idling operation without the operator turning on the switch 13 one by one.

The gist of the present invention is to set the target rotation speed characteristic by correcting the preset basic target rotation speed based on the prime mover rotation speed during no-load idling. The circuit for generating the signal shown, that is, the rewrite signal, is not limited to the above embodiment, and can be generated using various circuit configurations. Further, although the basic target rotational speed characteristics are stored as a function in the function generator, a table of accelerator pedal depression amount and prime mover rotational speed may be provided and the basic target rotational speed characteristics may be stored in this table.

In the configuration of the above embodiment, the accelerator pedal 10 serves as a command means, the controller 80 serves as a discharge volume control means, the function generator 181 serves as a storage means, the coefficient unit 182 and the deviation unit 8
3 constitutes a setting means, and the accelerator pedal depression amount Xp is a command value.

G0 Effects of the Invention According to the present invention, basic target rotation speed characteristics that are uniformly set in advance can be corrected with extremely simple operations according to mechanical deviations and play of individual prime movers and their peripheral equipment, changes over time, or altitude. This improves operability.

[Brief explanation of drawings]

FIG. 1 is a schematic overall configuration diagram showing an embodiment of the prime mover target rotation speed setting device for a hydraulically driven vehicle according to the present invention, FIG. 2 is a diagram showing the characteristics of accelerator pedal displacement and engine rotation speed, and FIG. Figure 4 is a diagram showing engine output torque characteristics,
5(a) and 5(b) are diagrams showing two other examples of the dual change signal generation circuit, FIG. 6 is a schematic overall configuration diagram showing one embodiment of a conventional prime mover target rotation speed setting device, and FIG. The figure is a diagram showing the conventional characteristics of accelerator pedal displacement and engine speed. 1: Engine 2: Variable displacement hydraulic pump 3.
4: Main pipe 5: Hydraulic motor 6: Electric regulator 7: Forward/forward selector switch 10: Accelerator pedal 11: Rotation speed sensor 12: Potentiometer 80
: Controller 181: Function generator 182: Coefficient unit 183: Adder 184: Deviation unit 185: Integrator Patent applicant Hitachi Construction Machinery Co., Ltd. Representative Patent attorney Fuyu Nagai Figure 1 Controller Figure 2 Figure 3 C 'Engine speed Fig. 4 Fig. 7 Accelerator rotation speed Fig. 5

Claims (1)

[Scope of Claims] 1) A variable displacement hydraulic pump driven by a prime mover, a hydraulic motor connected in a closed circuit to the hydraulic pump, a command means for commanding the rotation speed of the prime mover, and an actual rotation speed of the prime mover. a detection means for detecting the number of rotations, and a detection means for detecting the number of rotations according to the deviation between the target rotation speed read out based on the command value of the command means according to the target rotation speed characteristic set in advance and the detected actual rotation speed of the prime mover. A method for setting a prime mover target rotation speed characteristic of a hydraulic drive device having a discharge capacity control means for controlling a discharge capacity of a variable displacement hydraulic pump, the method comprising detecting the actual rotation speed of the prime mover under predetermined conditions and storing it in advance. A method for setting a target rotation speed characteristic of a prime mover for a hydraulic drive system, characterized in that the target rotation speed characteristic is set by correcting a certain basic target rotation speed characteristic using a detected actual rotation speed. 2) A variable displacement hydraulic pump driven by a prime mover, a hydraulic motor connected in a closed circuit to the hydraulic pump, a command means for commanding the rotation speed of the prime mover, and a detection means for detecting the actual rotation speed of the prime mover. and the variable displacement hydraulic pump according to the deviation between the target rotation speed read out based on the command value of the command means according to the target rotation speed characteristic set in advance and the detected actual rotation speed of the prime mover. A prime mover target rotation speed characteristic setting device for a hydraulic drive device having a discharge capacity control means for controlling a discharge capacity, a storage means for storing a basic target rotation speed characteristic, and a basic target stored in advance in the storage means. A prime mover target rotation speed characteristic setting device for a hydraulic drive system, comprising a setting means for setting the target rotation speed characteristic by correcting the rotation speed characteristic by the actual rotation speed detected under predetermined conditions. .