JPH0441942A - Automatic deceleration control device for hydraulically driven machinery - Google Patents

Abstract

PURPOSE:To optimal realize good cost performance and a low noise with automatic deceleration by measuring an interval of periods during which an operation lever of a hydraulic driving machine is set neutral, changing the automatic deceleration time under a next neutral condition according to the measured period, and improving the using feeling of the automatic deceleration function. CONSTITUTION:In a variable volume pump 6 which is driven by an engine 11 provided with a vuel jet pump 2 and a governor 3, a discharge flow rate by one rotation is changed by changing a tilting angle of an inclined plate 6a by means of the inclined plate driving mechanism 7. The pressure oil discharged from the pump 6 is supplied to a hydraulic actuator 9 which drives a running system or a working machine through a hydraulic valve 8. The hydraulic actuator 9 is operated by an operation lever 10. A neutral detector 18 composed of a cam 16, a switch 17 or the like is provided on the operation lever 10, and a detected output therefrom is input Lt is input to an automatic decelerator timer controller 20. The time of a neutral condition is measured. The automatic deceleration time suited to the measured value is computed, and the computed value Ti is output to a governor controller 13.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in the auto-deceleration function of a hydraulically driven machine such as a power shovel.

[Conventional technology]

The auto deceleration function aims to reduce fuel consumption and noise by lowering the engine speed when the operating lever is in neutral, and the conventional technology is shown in FIG.

In this conventional auto-deceleration control, when the operating lever becomes neutral (at time t), first at this time t. After the first auto deceleration time T+ (set value), the engine speed is reduced to the first deceleration speed N1, and further, after the second auto deceleration time T2 (set value), the engine speed is reduced to the second deceleration speed N2. control such as This auto-deceleration control is canceled when the neutral position of the operating lever is released.

[Problem to be solved by the invention]

However, in conventional auto-deceleration control, the first auto-deceleration time T1 and the second auto-deceleration time T2 are fixed, so under work conditions where, for example, the neutral time of the operating lever is slightly longer than the second auto-deceleration time T2. , the engine speed starts decreasing to the second deceleration speed N2 immediately before the operator releases the control lever from neutral.

Therefore, under such work conditions, it will take more time than usual for the engine speed to rise after the control lever is released from neutral, and the responsiveness of the hydraulic actuator to the control lever operation may be affected. It gets worse. Therefore, in the conventional technology, in order to prevent this, the operator must turn the auto-deceleration function switch from on to off each time during work to cancel the auto-deceleration control, which forces the operator to perform troublesome operations. .

Further, canceling auto-deceleration during work in this way goes against the original purpose of auto-deceleration control, which is low fuel consumption and low noise.

The present invention was made in view of the above circumstances, and
It is an object of the present invention to provide an auto-deceleration automatic control device that improves the feeling of using the auto-deceleration function and suitably achieves low fuel consumption and low noise due to auto-deceleration.

[Means to solve the problem]

In this invention, in the auto-deceleration automatic control device for a hydraulically-driven machine that reduces the engine speed to a predetermined speed after a predetermined auto-deceleration time interval has elapsed when the control lever of the hydraulically-driven machine becomes neutral, the control lever The present invention includes a neutral time measuring means for measuring a time interval during which the neutral time is in neutral, and an auto-deceleration time variable means for varying the auto-deceleration time at the next neutral time according to the measurement time of the neutral time measuring means.

[Effect]

According to this configuration, the neutral time from the time when the operating lever becomes neutral until the time when neutral is released is measured each time. Then, the next auto-deceleration time in neutral is variably controlled depending on the JFI constant value each time.

〔Example〕

Embodiments of the present invention will be described above with reference to the accompanying drawings.

Figure 1 shows the configuration of the hydraulic drive system of a hydraulically driven machine.An engine 1 includes a fuel injection pump 2 and a governor 3.
There is also a. A fuel control lever 3a of the governor 3 is driven by a motor 4, and a sensor 5 detects the drive position of the lever 3a.

The variable displacement pump 6 is driven by the engine 1,
By changing the tilt angle of the swash plate 6a by the swash plate drive mechanism 7, the discharge flow rate per rotation is changed. Pressure oil discharged from the pump is supplied via a hydraulic valve 8 to a hydraulic actuator 9 that drives a traveling system and a working machine.

The operating lever 10 operates the hydraulic actuator 9, and the displacement of the lever is detected by a potentiometer 11. Note that the operating lever 9 is shown as one operating lever to represent a plurality of operating levers.

The output of potentiometer 1] is the output of pump controller 12.
The pump controller 12 switches and drives the hydraulic valve 8 according to the output of the potentiometer.

The pump controller 12 also has a heavy excavation mode.

Mode selection signals such as excavation mode 1 fine operation mode and auto deceleration mode are input, and pump controller 1
2 controls the drive of the swash plate drive mechanism 7 in accordance with the selected mode, thereby performing constant control of the combined absorption power of the pump 6 corresponding to the selected mode. Further, the pump controller 12 obtains a throttle signal corresponding to the selected mode and inputs this to the governor controller 13.

The throttle amount setting device 14 includes a dial 14a and a potentiometer 1 that detects rotational displacement of the dial 14a.
4b. The engine rotation sensor 15 detects the engine rotation speed and inputs this to the governor controller 13.

The governor controller 13 compares the first throttle signal output from the setting device 14 and the second throttle signal output from the pump controller 12, and drives the motor 4 based on the smaller signal. do.

The operating lever is provided with a neutral detector 18 consisting of a cam 16, a switch 17, etc., and its detection output Lt is input to the auto-deceleration timer controller 20.

An auto-deceleration timer controller (hereinafter abbreviated as timer controller) 20 outputs the output Lt of the neutral detector 18.
Based on #1, measure the neutral time (the time from when the operating lever 10 becomes neutral to when neutral is released), and calculate the second auto deceleration time T2 (see Figure 7) suitable for this measured value. Then, the calculated value TI (=Tz
) is output to the governor controller 13, and its internal configuration is shown in FIG.

The counter 30 adds a total of δP1 to the neutral time N based on the output of the neutral detector 18, and inputs the output N to the MPU 31.

The ROM 32 stores a conversion table showing the correspondence between the neutral time N and the second auto-deceleration time T2, as shown in FIG.

The second auto-deceleration time T2 is the neutral time N
If the time when N is measured is the current time, it represents the second auto deceleration time at the next neutral time.According to this conversion table, as the neutral time N becomes longer, the second auto deceleration time at the next neutral time increases. T2
is shorter.

That is, when the neutral time is long, the engine speed is reduced earlier next time, and when the neutral time is short, the engine speed is reduced later next time.

The MPU 31 determines the optimum auto-deceleration time T2 based on the neutral time N inputted from the counter 30 and the conversion table stored in the ROM 32, and its operation is shown in FIG.

When the engine 1 of the hydraulically driven machine is started, the MPU 31
initializes the N max flag (hereinafter simply referred to as FLAG) in its own circuit to O and resets the counter 30 (step 110).

The above FLAG becomes 1 when the count value N of the counter 30 exceeds a predetermined upper limit value N1llaX.

After the engine starts, the MPU 31 detects the neutral detector 18
Step 120) determines whether the operating lever 10 is in neutral based on the output Lt, and if it is neutral, determines whether the FLAG is 1 or 0 (step 120).
130) When FLAG is 0, the counter 30 starts counting (step 140).

Then, when the MPU 31 detects that the neutral state has ended based on the neutral detection signal Lt, the MPU 31 starts the counter 3
The counting operation of 0 is stopped, the count value N at this time is taken into the count value register Nl in the own circuit, and the count value of the counter 30 is reset (steps 170 to 200).

Note that the count value N of the counter 30 is a predetermined upper limit value N.
When the value exceeds wax, the MPU 31 uses this upper limit value N.
While importing wax, the FLAG is set to 1 (steps 210, 220).

Next, the MPU 31 calculates a second auto-deceleration time Ti corresponding to the loaded count value Nl using the conversion table in the ROM 32 (step 240).

The MPU 31 inputs the second auto-deceleration time TI calculated in this way to the governor controller 13 (steps 250 and 260).

Thereafter, the MPU 31 determines that the lever is neutral in the same manner as described above, and then starts the counter 30 to perform a neutral time measurement operation (steps 1.20 to 20).
0,260).

Note that the procedure via steps 150 and 160 is such that when the count value N becomes equal to or greater than the upper limit value Nfflax,
It is provided to stop and reset the counter 30 and to reset the FLAG.

In the governor controller 13, when the second auto-deceleration time T1 is input from the MPU 31, this input value is temporarily held, and when the next neutral detection signal Lt is input, this input value TI is set as the second auto-deceleration time T2. Perform auto-deceleration control (see Figure 7).

That is, the governor controller 13 gives the first deceleration rotation speed N to the motor 4 as a command value after the time T has elapsed since the next neutral state, and then (TI-'
r,) Auto-deceleration control is performed in which the second deceleration rotation speed N2 is output to the motor 4 after a period of time has elapsed.

FIG. 5 shows step 240 of the embodiment of FIG. This shows another embodiment in which step 241 is inserted between step 250 and step 250.

In this step 241, the second auto-deceleration time TI calculated using the conversion table 32 is input to a low-pass filter (digital filter), and by passing it through the low-pass filter, By performing the processing, the waveform is smoothed and the value T
An attempt is made to control sudden changes in I.

FIG. 6 shows another embodiment in which steps 240 and 250 in FIG. 4 are replaced with steps 240 to 247.

In this embodiment, a predetermined standard value Tx (an average value as the second auto-deceleration time T2) is set for the second auto-deceleration time T2 (step 242), so that the second auto-deceleration time TI calculated this time is the same as the second auto-deceleration time TI calculated last time. Distinguish whether the change is toward the standard value Tx or away from the standard value Tx for the second autodeceleration time Ti-1 (step 24B), and different types of low-pass filters are used for both of these cases. Let it pass.

That is, when moving away from the standard value Tx, a low pass filter using elk as a filter coefficient is passed,
The value fil after such filter processing is output to the governor controller 13 (steps 244 and 245). If it approaches the standard value, the filter coefficient is passed through a low-pass filter using a filter coefficient c2k with a different cutoff frequency, and the value after this filter processing is outputted as f21 to the governor controller 13 (steps 246 and 247).
).

That is, in this embodiment, the responsiveness is made different by applying different filters when the calculated second auto-deceleration time TI approaches the standard value Tx and when it moves away from the standard value Tx. , I try to change it slowly when moving away.

In this way, in the device of this embodiment, the operating lever 10
Auto-deceleration control is performed in which the neutral measurement time TI is measured each time, and the next auto-deceleration time is varied according to the neutral measurement time TI.

Note that in this embodiment, a two-stage auto-deceleration function is used, and the second auto-deceleration time T2 is varied according to the previous neutral time, but the first auto-deceleration time T1 is variable and the second auto-deceleration The time T2 may be fixed, or both the first auto-deceleration time TI and the second auto-deceleration time T2 may be variable. Furthermore, the auto deceleration speed is 1
The present invention may also be applied to one-stage auto-deceleration control.

Furthermore, in the above embodiment, the governor controller 13 holds the current calculated value TI for one cycle and uses this held value for auto-deceleration control during the next neutral state, but the MPU 31 in FIG. The count value N of 30 may be held for one cycle, or the MPU 31 may hold the calculated value TI for one cycle.

〔Effect of the invention〕

As explained above, in the present invention, the neutral time is measured and the next auto-deceleration time is appropriately varied according to this measured value, thereby improving the usability of auto-deceleration control and achieving the purpose of auto-deceleration. This makes it possible to achieve a higher level of low fuel consumption and low noise.

[Brief explanation of the drawing]

The first is a schematic configuration diagram showing an embodiment of the present invention, FIG. 2 is an internal configuration diagram of an auto-deceleration timer controller, and FIG. 3 is an R
FIGS. 4 to 6 are flowcharts showing the operation of the MPU of the embodiment. FIG. 7 is a time chart of auto-deceleration control. 1...Engine, 2...Fuel injection pump, 3...
Governor, 3a...Fuel control lever, 4...
Motor, 5...sensor, 6...variable displacement pump,
6a... Swash plate, 7... Swash plate angle drive mechanism, 8... Hydraulic valve, 9... Hydraulic actuator, 10... Operation lever 11, 14a... Potentiometer, 12
... Pump controller, 13... Governor controller, 14... Throttle amount setter, 14a... Dial, 15... Rotation sensor, 16... Cam, 17
...Switch, 18...Neutral detector, 20
... Auto deceleration timer controller, 30... Counter, 31... MPU, 32... ROM Figure 2 = Coat Tsuru Senma Figure 3 Figure 5

Claims (4)

[Claims] (1) In an auto-deceleration automatic control device for a hydraulically-driven machine that reduces the engine speed to a predetermined speed after a predetermined auto-deceleration time interval has elapsed when the control lever of the hydraulically-driven machine becomes neutral, the control lever The vehicle is characterized by comprising: a neutral time measuring means for measuring a time interval during which the vehicle is in neutral; and an auto-deceleration time variable means for varying the auto-deceleration time at the next neutral time according to the measurement time of the neutral time measuring means. Automatic deceleration control device for hydraulically driven machinery. (2) The auto deceleration time is the first auto deceleration time from when starting neutral to the time when the engine speed is lowered to the first deceleration speed, and the first auto deceleration time from when starting neutral to the time when the engine speed is lowered from the first deceleration speed to the second deceleration speed. 2. The hydraulically driven machine according to claim 1, wherein the automatic deceleration time is a second auto deceleration time up to a point in time when the neutral measurement time is lowered to a certain value, and the auto deceleration time variable means varies the second auto deceleration time in accordance with the neutral measurement time. Auto deceleration automatic control device. (3) The auto-deceleration automatic control device for a hydraulically driven machine according to claim (1), wherein the auto-deceleration time variable means includes filter means for removing high frequency components of the auto-deceleration time determined according to the measured time. (4) A standard auto-deceleration time is set in the auto-deceleration time variable means, and a filter coefficient of the filter means is determined when the auto-deceleration time determined according to the measurement time approaches and moves away from the standard auto-deceleration time. The automatic deceleration control device for a hydraulically driven machine according to claim 3, wherein the automatic deceleration control device for a hydraulically driven machine is made to have different values.