JPS6253725B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic drive device for driving an inertial load.

FIG. 1 is a diagram showing a conventional hydraulic drive device for raising and lowering a boom of a construction machine such as a hydraulic excavator. In the figure, 1 is a hydraulic source, 4 is a hydraulic cylinder operated by the discharged pressure oil of the hydraulic source 1, 7 is an inertial load driven by the hydraulic cylinder 4, 1
0 is an operating device such as a lever or dial, 11 is a signal generator that outputs an operating signal such as voltage, oil pressure, air pressure, etc. x ₁ proportional to the amount of physical operation of the operating device 10,
The hydraulic cylinder 4 is operated by the operating device 10 and the signal generator 11.
Configure an operating device to set the speed of the Reference numeral 14 denotes a flow rate control device that controls the hydraulic cylinder 4 by supplying pressure oil to the hydraulic cylinder 4 at a flow rate corresponding to the operating device _x1 .

In this hydraulic drive device, when the operating device 10 is switched from the neutral position to the operating position, the pressure oil discharged from the hydraulic source 1 is supplied to the hydraulic cylinder 4, and the hydraulic cylinder 4 moves at a speed corresponding to the amount of operation of the operating device 10. It operates with. In this case, as shown in FIG. 2a, the time t ₀
If the actuator 10 is operated in steps from the neutral position to the operating position by x _A , and the actuator 10 is returned to the neutral position in steps at time _t2 , the hydraulic cylinder 4
The speed change is as shown in Fig. 2b. That is, the hydraulic cylinder 4 is accelerated at a constant acceleration from time t ₀ to time t ₁ , and at time t ₁ the operation amount x of the operating device 10 is increased.
It reaches a speed V _A corresponding to _A , operates at a constant speed V _A from time t ₁ to time t ₂ , and decelerates at a constant deceleration from time t ₂ to time t ₃ and comes to rest. In this case, when the load value of the inertial load acting on the hydraulic cylinder 4 is large, and the acceleration/deceleration of the hydraulic cylinder 4 at the time of starting and stopping is large, the force acting on the hydraulic cylinder 4 becomes large, causing the vehicle body to shake significantly. , the support portion of the hydraulic cylinder 4 may be damaged, impairing safety and stability. Therefore, when the load value of the inertial load 7 is large, it is conceivable to operate the controller 10 slowly, but in this case, the operator needs to check the load value of the inertial load 7 for each operation. Since this has to be confirmed, operability deteriorates.

It is also possible to reduce the acceleration/deceleration of the hydraulic cylinder 4 regardless of the load value of the inertial load 7, but in this case, even when the load value of the inertial load 7 is small, the acceleration/deceleration of the hydraulic cylinder 4 is small. As you get used to it, the operability decreases.

The first invention was made to solve the above-mentioned problem, and even if the operator operates without checking the magnitude of the inertial load, if the inertial load is small, It is an object of the present invention to provide a hydraulic drive device in which a large force does not act on a hydraulic actuator when the acceleration/deceleration of the hydraulic actuator is not small and the load value of the inertial load is large.

In order to achieve this objective, the first invention includes a hydraulic actuator that drives an inertial load;
In a hydraulic drive device having an operating device that sets the speed of the hydraulic actuator, and a flow rate control device that supplies pressure oil to the hydraulic actuator at a flow rate according to an output signal of the operating device, the load value of the inertial load is determined. A load detection device for detecting is provided between the operating device and the flow rate control device, and when the operating device is operated, the larger the load value of the inertial load is, the more the load detecting device outputs a signal that rises and falls gradually. A speed control device shall be provided.

In the hydraulic drive device of the first invention, when the operating device is operated, the acceleration/deceleration control device outputs a signal that rises as the load value of the inertial load becomes larger and falls more slowly. If is small, the acceleration/deceleration of the hydraulic actuator will not become small, and if the load value of the inertial load is large, the acceleration/deceleration of the hydraulic actuator will be small, so a large force will not act on the hydraulic actuator. Moreover, since the load value of the inertial load is detected by the load detector, there is no need for the operator to confirm the load value of the inertial load for each operation.

By the way, when the deceleration of the hydraulic actuator is reduced when the load value of the inertial load is large as in the first invention, if the speed of the hydraulic actuator is large, the time from the time when the operating device is operated until the hydraulic actuator stops is reduced. Since the time, that is, the stop time becomes long, the operation cannot be performed safely.

The second invention was made to solve this problem, and even if the operator operates without checking the magnitude of the inertial load, if the inertial load is small, the hydraulic To provide a hydraulic drive device in which a large force is not applied to a hydraulic actuator when the acceleration/deceleration of the actuator is not small and the load value of an inertial load is large, and the stopping time of the hydraulic actuator is not prolonged. The purpose is to

In order to achieve this object, the second invention includes a hydraulic actuator that drives an inertial load;
In a hydraulic drive device having an operating device that sets the speed of the hydraulic actuator, and a flow rate control device that supplies pressure oil to the hydraulic actuator at a flow rate according to an output signal of the operating device, the load value of the inertial load is determined. A load detection device for detecting is provided between the operating device and the flow rate control device, and when the operating device is operated, the larger the load value of the inertial load is, the more the load detecting device outputs a signal that rises and falls gradually. A speed control device is provided between the acceleration/deceleration control device and the flow rate control device, and when the load value of the inertial load is large, the maximum speed signal is set to a small value, and when the load value of the inertial load is small, the maximum speed signal is set to a small value. The signal is set large, and when the output signal of the acceleration/deceleration control device is smaller than the maximum speed signal, the output signal of the acceleration/deceleration control device is output, and when the output signal of the acceleration/deceleration control device is larger than the maximum speed signal, the output signal of the acceleration/deceleration control device is output. A speed limiting device is provided to output the maximum speed signal.

In the hydraulic drive device of the second invention, the first
Similar to the hydraulic drive device of the invention, when the load value of the inertial load is small, the acceleration/deceleration of the hydraulic actuator does not become small, and when the load value of the inertial load is large, a large force acts on the hydraulic actuator. There is no need for the operator to check the load value of the inertial load for each operation, and the speed limiter allows the maximum speed signal to be set to a small value when the load value of the inertial load is large. Therefore, when the load value of the inertial load is large, the maximum speed of the hydraulic actuator is set small, so even when the deceleration of the hydraulic actuator is small, the stop time of the hydraulic actuator does not become long.

FIG. 3 is a diagram showing a hydraulic drive device according to the first invention. In the figure, 12 is a load detection device that detects the load value of the inertial load 7, and 13 is a signal generator 11.
The acceleration/deceleration control device 13 is an acceleration/deceleration control device provided between the flow control device 14 and the output signal of the signal generator 11, that is, the operation signal _x1 , and the output signal of the load detection device 12, that is, the load signal L. When the load signal L is input and the operating device 10 is operated, the larger the load signal L is, the more slowly the signal is output, and the output signal of the acceleration/deceleration control device 13 is
x ₂ is input to the flow rate control device 14.

FIG. 4 is a diagram for explaining an example of a method for detecting a load value of an inertial load by the load detection device 12, that is, a diagram showing a hydraulic excavator. In the figure, 15 is a traveling part, 16 is an upper revolving body rotatably attached to the traveling part 15, 17 is a swing hydraulic motor for rotating the upper revolving body 16, 18 is a boom, 19 is an arm, and 20 is a bucket. , 21 is a boom cylinder,
22 is an arm cylinder, 23 is a bucket cylinder, and the boom 18, arm 19, bucket 20, and cylinders 21 to 23 constitute a front section 24. Then, a bucket 20 is attached to the front part 24.
The load value _M1 of the inertial load including the load 25 inside, that is, the inertial load of the boom cylinder 21, is determined by detecting the oil pressure p in the lower cylinder chamber 26 of the boom cylinder 21 and the angle θ between the boom cylinder 21 and the vertical line. You can easily find it by doing this. That is, the load value M ₁ =f ₁ (p, θ). Also,
Load value M ₂ of the inertial load for the swinging operation of the upper rotating body 16, that is, the inertial load of the hydraulic motor 17
is the value obtained by adding the load value M ₃ =f ₂ (p, θ) of the front portion 24 (including the load 25) to the constant load value M ₀ determined by the shape and weight of the upper revolving structure 16. That is, the load value M ₂ =M ₀ +M ₃ .

Note that the load value M of the inertial load can generally be detected from the oil pressure in the hydraulic actuator, the length of the boom, distortion, or a combination thereof, depending on the installation position of the hydraulic actuator and the direction of the inertial load.

FIG. 5 is a diagram showing details of the acceleration/deceleration control device 13. In the figure, 27 is an acceleration/deceleration controller that receives the load signal L and outputs a small signal Δx _L that is small when the load signal L is large and large when the load signal L is small, and 28 is an acceleration/deceleration controller 2.
An integrator 29 integrates the output signal Δx _L of the integrator 28 and the operation signal x ₁ , and when the signal x _L is smaller than the signal x ₁ , _the signal x _L
It is a limiter that outputs a signal x ₁ when the signal x _L is larger than the signal x ₁ . Note that the acceleration/deceleration controller 27 starts operating when the operation signal _x1 changes from 0 to a value other than 0. Next, the operation will be explained. When the operation signal x ₁ changes from 0 to a value other than 0, the acceleration/deceleration controller 27 starts outputting the signal Δx _L. Since this signal Δx _L is small when the load signal L is large and large when the load signal L is small, the signal x _L of the integrator 28 rises slowly when the load signal L is large, and rises slowly when the load signal L is small. It gets sudden. Then, while the signal x _L is smaller than the operation signal x ₁ , the limiter 29 outputs the signal x _L ,
When the signal x _L becomes larger than the operation signal x ₁ , the limiter 29 outputs the signal x ₁ .

In addition, in the case of an electrical signal, the acceleration/deceleration control device 13 uses an operational amplifier, a resistor,
It can be easily made by combining capacitors, etc., and in the case of hydraulic signals, it can be made by inserting an accumulator in the middle of the signal transmission line and changing the sealing pressure of the accumulator.

Furthermore, as a specific example of the flow rate control device 14,
There are those that use a pressure-compensated flow control valve that outputs a flow rate proportional to an input signal, and those that use a variable pump that outputs a discharge amount that is proportional to an input signal. In other words, the opening degree of the variable throttle valve of the pressure-compensated flow control valve becomes a value proportional to the input signal, and the hydraulic cylinder 4 is supplied with pressure oil at a flow rate proportional to the opening degree of the pressure-compensated flow control valve. Therefore, the pressure compensated flow control valve supplies the hydraulic cylinder 4 with pressure oil at a flow rate proportional to the input signal. Furthermore, the tilting angle of the variable pump's swash plate is proportional to the input signal, and the hydraulic cylinder 4 is supplied with pressure oil at a flow rate proportional to the tilting angle of the variable pump's swash plate. supplies pressure oil to the hydraulic cylinder 4 at a flow rate proportional to the input signal. In this manner, the flow rate control device 14 supplies pressure oil to the hydraulic cylinder 4 at a flow rate proportional to the input signal.
Moreover, the hydraulic cylinder 4 operates at a speed proportional to the flow rate of pressure oil supplied from the flow rate control device 14.
Since the hydraulic cylinder 4 operates at a speed proportional to the input signal 4, the hydraulic cylinder 4 operates at an acceleration/deceleration rate proportional to the rate of change of the input signal. Therefore, by making the rise and fall of the input signal of the flow rate control device 14 gentle when the hydraulic cylinder 4 is started and stopped, the acceleration and deceleration when the hydraulic cylinder 4 is started and stopped can be reduced.

Next, the operation in the above configuration will be explained. When the operator 10 is operated, the signal generator 1
1, an operation output x _1A proportional to the operation amount x _A of the operating device 10 is output. Then, load detection device 1
If the load signal L output from 2 is large,
A signal x _L with a gradual rise is output from the acceleration/deceleration control device 13, and when the load signal L is small, a signal x _L with a steep rise is output from the acceleration/deceleration control device 13. Since the flow rate control device 14 supplies pressure oil to the hydraulic cylinder 4 at a flow rate proportional to the signal x _L (x ₂ ), the hydraulic cylinder 4 changes its speed in accordance with the signal x _L . Then, when the signal x _L becomes larger than the signal x _1A , the acceleration/deceleration control device 13 outputs the signal x _1A , so that the hydraulic cylinder 4 moves at a speed V corresponding to the signal x _1A .
At _A , the speed is constant.

To explain this according to FIG _. 6, when the operating signal x ₁ becomes x _1A stepwise at time t ₀ and becomes 0 stepwise at time t ₂ , the load signal L becomes L Assuming that ₁ < L ₂ < L ₃ , the output signal x ₂ of the acceleration/deceleration control device 13 rises more slowly as the load signal L becomes larger, and as a result, the speed change of the hydraulic cylinder 4 also changes as the load signal L becomes larger. The more slowly the rise becomes. That is, when the load value M of the inertial load 7 is large, the acceleration/deceleration of the hydraulic cylinder 4 becomes small, and when the load value M is small, the acceleration/deceleration of the hydraulic cylinder 4 becomes large. Note that the broken line indicates the conventional case. In this way, when the load value M of the inertial load 7 is small, the acceleration/deceleration of the hydraulic cylinder 4 does not become small.
Operability does not deteriorate, and when the load value M of the inertial load 7 is large, the acceleration/deceleration of the hydraulic cylinder 4 becomes small, so a large force is not applied to the hydraulic cylinder 4, and the vehicle body does not shake significantly. , the support part of the hydraulic cylinder 4 will not be damaged, and safety and stability will not be impaired.
Furthermore, since the load value of the inertial load 7 is detected by the load detector 12, there is no need for the operator to confirm the load value of the inertial load for each operation.

The above has described the case where the load signal L corresponding to the load value M of the inertial load 7 that changes every moment is output from the load detection device 12. For example, when the hydraulic excavator shown in FIG. 4 is excavating with the bucket 20. Since the oil pressure p in the lower cylinder chamber 26 of the boom cylinder 21 may fluctuate regardless of the load value M, when detecting the load value M using the oil pressure p, it is necessary to accurately detect the load value M. It may not be possible. Therefore, when the operating device 10 is operated in a certain direction from the neutral position, that is, when the operation signal x ₁ changes from 0 to a certain value other than 0, the load value M of the inertial load 7 is detected and the load value The load detection device 12 is configured to store M until the operating device 10 returns to the neutral position and is operated in a certain direction again, that is, until the operating signal _x1 becomes 0 and becomes a certain value other than 0 again. For example, the above-mentioned drawbacks can be eliminated. Note that it is easy to configure the load detection device 12 in this manner using current electronic engineering technology. In this case, the operation signal x ₁ , load value M,
The relationship between the load signal L and the speed V of the hydraulic cylinder 4 will be described in detail with reference to FIG. When the operating device 10 is suddenly operated from the neutral position (x=0) at time t ₀ , an operating signal x _1A proportional to the operating amount x _A of the operating device 10 is output from the signal generator 11, and the load detecting device 12
detects the load value M _A of the inertial load at time t ₀ ,
The load signal L _A corresponding to the load value M _A is held and output. Then, from the acceleration/deceleration control device 13, a signal x ₂ having a rising edge corresponding to the load signal L _A is output.
_A (x _LA ) is output, this signal x _2A is input to the flow rate control device 14, and the speed V of the hydraulic cylinder 4 changes with an acceleration corresponding to the load signal _LA (V _LA ),
The steady speed V _A corresponds to the operation signal x _1A . Next, when the operation signal x ₁ is changed stepwise from x _1A to 0 by operating the controller 10 at time t ₂ , the load detection device 12 does not perform new detection and at time t Since the load signal _LA detected at ₀ is held, the speed V of the hydraulic cylinder 4 changes at a deceleration corresponding to the load signal _LA (V _LA ) and eventually becomes 0. Next, when the operation signal x ₁ is changed stepwise from 0 to x _1B again at time t ₄ , the load detection device 12 detects the load value M _B of the inertial load at time t ₄ .
is detected, and a load signal L _B corresponding to the load value M _B is held and output. As a result, the speed V of the hydraulic cylinder 4 changes with an acceleration corresponding to the load signal L _B (V _LB ), and becomes a steady speed V _B corresponding to the operation signal x _1B . That is, the load value M of the inertial load is M _A > M _B
At this time, the load signal L is L _B >L _B , the hydraulic cylinder 4 operates at an acceleration/deceleration rate corresponding to the load signal L, and the speed V _LA of the hydraulic cylinder 4 changes more slowly than the speed V _LB.

As described above, when the load value M of the inertial load is large, if the acceleration/deceleration of the hydraulic cylinder 4 is made small, if the load value M of the inertial load is large and the steady speed of the hydraulic cylinder 4 is large, it will be difficult to This may take an inconvenient amount of time, which poses a safety problem. Therefore, when the load value M of the inertial load is large, it is necessary to reduce the maximum speed of the hydraulic cylinder 4, and when the load value M is small, it is necessary to increase the maximum speed of the hydraulic cylinder 4.

FIG. 8 shows a hydraulic drive system according to the second invention, that is, a hydraulic cylinder 4 corresponding to a load value M of an inertial load.
2 is a diagram illustrating a hydraulic drive system that includes a device that delays the rise in speed of the hydraulic cylinder 4 and a device that limits the maximum speed of the hydraulic cylinder 4 in accordance with a load value M. FIG. In the figure, 30 is the acceleration/deceleration control device 13
The speed limiting device 30 is a speed limiting device provided between the acceleration/deceleration control device 1 and the flow rate control device 14.
As shown in FIG. ₉ , when the load signal L is large, the maximum speed signal x nax is set small, and when the load signal L is small, the maximum speed signal x _nax is set to a _small value. When the output signal _x2 of the acceleration/deceleration control device 13 is smaller than the maximum speed signal _xnax , the output signal
x ₂ , and the output signal x ₂ is the maximum speed signal x _na
When it becomes larger than _x , the maximum speed signal x _nax
The output signal x ₃ of the speed limiter 30 is input to the flow rate controller 14 . Note that such a speed limiting device 30 can be easily realized using a limiter circuit.

The operation of the above configuration will be explained with reference to FIG. When the output signal of the signal generator 11, that is, the operation signal _x1 changes stepwise to _x1A as shown in a, the output signal of the load detection device 12, that is, the load signal L is _L1 as shown in b. Then, the output signal x ₂ of the acceleration/deceleration control device 13 is
As shown in c, the change has a delay in rising commensurate with the load signal _L1 . This output signal x ₂
is compared with the maximum speed signal x _nax1 corresponding to the load signal L ₁ in the speed limiting device 30, and if the output signal x ₂ is smaller than the maximum speed signal x _nax1 , the speed limiting device An output signal x ₂ is output from 30. That is, when the operation signal x _1A is smaller than the maximum speed signal x _nax1 , the output signal
x ₂ is output (x ₃ ) from the speed limiter 30. Then, since the speed V of the hydraulic cylinder 4 changes in response to the output signal x ₃ , the speed V becomes a steady speed V _A corresponding to the operation signal x _1A , as shown in e. Further, when the operation signal x ₁ becomes x _1A at time t ₄ , if the load signal L is L ₂ and the maximum speed signal x _nax2 corresponding to the load signal L ₂ is smaller than the operation signal x _1A , the output signal While x ₂ is smaller than the maximum speed signal x _nax2 , the speed limiting device 30 outputs the output signal x ₂ , but when the output signal x ₂ becomes larger than the maximum speed signal x _nax2 , the speed limiting device 30 outputs the maximum signal A speed signal _xnax2 is output. As a result, the steady speed of the hydraulic cylinder 4 is limited to the maximum speed V _nax2 corresponding to the load signal L. Therefore, even when the deceleration of the hydraulic cylinder 4 is small because the load signal L is large, that is, when the speed change of the hydraulic cylinder 4 is slow, it is possible to shorten the stop time.

In the above-described embodiments, the case where the hydraulic actuator is a hydraulic cylinder has been described, but it goes without saying that the present invention can also be applied to a hydraulic actuator such as a hydraulic motor.

As explained above, in the hydraulic drive device according to the first invention, when the load value of the inertial load is small, the acceleration/deceleration of the hydraulic actuator does not become small, so the operability does not deteriorate. In addition, even if the load value of the inertial load is large, a large force will not act on the hydraulic actuator, so safety and stability will not be compromised. Since there is no need to check whether the Further, in the hydraulic drive device according to the second invention, safety and stability are not impaired, and operability is not reduced, and even if the deceleration of the hydraulic actuator is small, the stop time of the hydraulic actuator is Since it does not take too long, it can be operated safely. As described above, the effects of the first and second inventions are remarkable.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional hydraulic drive device, FIG. 2 is a graph for explaining the operation of the conventional hydraulic drive device, FIG. 3 is a diagram showing a hydraulic drive device according to the first invention, and FIG. is a diagram for explaining an example of a method for detecting the load value of an inertial load, FIG. 5 is a diagram showing details of the acceleration/deceleration control device, and FIGS. 6 and 7 are diagrams showing the operation of the hydraulic drive device according to the present invention. Graphs for explanation, FIG. 8 is a diagram showing the hydraulic drive device according to the second invention, FIG. 9 is a graph showing the relationship between the load signal L and the maximum speed signal x _nax , and FIG. 10 is the graph shown in FIG. 8. It is a graph for explaining the operation of the shown hydraulic drive device. 4... Hydraulic cylinder, 10... Operating device, 11...
...Signal generator, 12...Load detection device, 13...
...Acceleration/deceleration control device, 14...Flow rate control device, 3
0... Speed limiter.

Claims (1)

[Claims] 1. A hydraulic actuator that drives an inertial load;
In a hydraulic drive device having an operating device that sets the speed of the hydraulic actuator, and a flow rate control device that supplies pressure oil to the hydraulic actuator at a flow rate according to an output signal of the operating device, the load value of the inertial load is determined. A load detection device for detecting is provided between the operating device and the flow rate control device, and when the operating device is operated, the larger the load value of the inertial load is, the more the load detecting device outputs a signal that rises and falls gradually. A hydraulic drive device characterized by being provided with a speed control device. 2. The hydraulic pressure according to claim 1, wherein the load detection device is one that detects the load value of the inertial load when the operating device is operated from a neutral position in a certain direction. Drive device. 3 a hydraulic actuator that drives an inertial load;
In a hydraulic drive device having an operating device that sets the speed of the hydraulic actuator, and a flow rate control device that supplies pressure oil to the hydraulic actuator at a flow rate according to an output signal of the operating device, the load value of the inertial load is determined. A load detection device for detecting is provided between the operating device and the flow rate control device, and when the operating device is operated, the larger the load value of the inertial load is, the more the load detecting device outputs a signal that rises and falls gradually. A speed control device is provided between the acceleration/deceleration control device and the flow rate control device, and when the load value of the inertial load is large, the maximum speed signal is set to a small value, and when the load value of the inertial load is small, the maximum speed signal is set to a small value. The signal is set large, and when the output signal of the acceleration/deceleration control device is smaller than the maximum speed signal, the output signal of the acceleration/deceleration control device is output, and when the output signal of the acceleration/deceleration control device is larger than the maximum speed signal, the output signal of the acceleration/deceleration control device is output. A hydraulic drive device comprising a speed limiting device that outputs the maximum speed signal. 4. The hydraulic pressure according to claim 3, wherein the load detection device is one that detects the load value of the inertial load when the operating device is operated from a neutral position in a certain direction. Drive device.