JPH06193608A - Automatic stop device for double acting hydraulic actuator - Google Patents

Abstract

PURPOSE:To improve performance of a double-acting actuator and its operability in an automatic stop device for the double acting hydraulic actuator. CONSTITUTION:Operation of a double-acting hydraulic actuator is artificially suspended immediately before an operation limit position under a condition of deceleration controlling. Then, the double-acting hydraulic actuator 1 is restarted for the side of the operation limit position. A pilot signal value at a suspension point where the upper limit value is regulated is not less than a pilot signal value enough to operate the double-acting hydraulic actuator 1 to the extent that a carryover passage is throttled more than required on the way of low speed control areas 3D, 3E of a hydraulic control valve 3. When the operation of an operation lever 18 is started, the actuator 1 is immediately restarted for the side of the operation limit position. Finally, the hydraulic control valve 3 is set at a neutral position 3A at the operation limit position, bringing about automatic stop.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic stop device for automatically stopping the operation of a double-acting hydraulic actuator at a predetermined limit operating position.

[0002]

2. Description of the Related Art Conventionally, in a hydraulic working machine, for example, a boom hydraulic crane, in order to ensure work safety, for example, when a boom is turned, a collision of the boom with other structures is avoided. In order to avoid or prevent the crane's tipping moment from exceeding the allowable moment, when the boom's turning position reaches the limit in terms of position or moment, double action of the hydraulic motor, etc. It is customary to equip an automatic stop device for forcibly stopping the boom turning operation using a hydraulic actuator regardless of the operator's intention (that is, regardless of the tilting operation of the operating lever).

By the way, the operation control of such a double-acting hydraulic actuator is carried out by connecting a hydraulic control valve for controlling the supply and discharge of the pump hydraulic pressure to the double-acting hydraulic actuator to a carry-over connecting the pump hydraulic pressure to the tank oil passage. A neutral position in which the oil passage is opened and the pair of control ports is cut off, and a switching position in which the pump oil passage and the tank oil passage are connected to the corresponding pair of control ports and the carryover oil passage is cut off, Between the neutral position and the switching position, the connection of the pump oil passage and the tank oil passage to the corresponding control oil passage is gradually increased, and a low speed control area for narrowing down the carryover oil passage is provided. It is composed of a four-way three-position type spring center type hydraulic control valve that is operated, and the hydraulic control valve is operated by an operator. It is performed by switching the pilot signal output in response to dynamic operation amount.

The automatic stop control of the double-acting hydraulic actuator in the hydraulic control device having the above-mentioned structure is performed from the viewpoint of alleviating a shock when the double-acting hydraulic actuator is automatically stopped at the operation limit position. A predetermined area on the front side in the operating direction from the operation limit position is set as a braking area, and when the operating state of the double-acting hydraulic actuator reaches a state corresponding to this braking area, the double-acting hydraulic actuator is gradually decelerated. It is customary to adopt a control mode in which the operation is finally completely stopped at the operation limit position.

As a concrete control method in this case, a system as shown in FIG. 5 has been generally used. That is, the approach rate of the operating state of the double-acting hydraulic actuator with respect to the actuating limit position is used as a parameter, and, for example, the range of the approach rate of 90% to 100% (that is, actuating limit position) is set as the braking area, and the double-acting hydraulic actuator is -When the operating state reaches 90% of the approach rate with the operation of the actuator, the deceleration control is started from this point, and the value of the pilot signal input to the hydraulic control valve becomes zero at the approach rate of 100%. So that the current value (P ₁ ) is linearly decreased (that is, the hydraulic control valve is linearly changed from its switching position to the neutral position via the low speed control region), and the hydraulic control valve is operated at the operation limit position. As a neutral position, the operation of the double-acting hydraulic actuator is stopped.

[0006]

However, the automatic stop device of such a control system has the following problems. That is, when the operator continues to operate the operation lever without noticing that the operating state of the double-acting hydraulic actuator is approaching the operation limit position, the operation of the double-acting hydraulic actuator is performed as described above. Is automatically stopped at the operation limit position, but the operator notices that the operating state of the double-acting hydraulic actuator is approaching the operation limit position, and immediately before the operation limit position (for example, as shown in FIG. When the operation lever is temporarily stopped by returning the operation lever to the neutral position (at the point a), the pilot signal value (P ₃ ) at the time of this stop is the hydraulic control. The pilot signal value (P ₂ : corresponding to the minimum hydraulic pressure sufficient to restart the double-acting hydraulic actuator by operating the valve 3 in the middle of the low-speed control region and until the carry-over oil passage is throttled to a predetermined value or more. Since If this pilot signal value is lower than the reference pilot signal value (below), even if the operator again operates the operating lever in the direction of approaching the double-acting hydraulic actuator to the operation limit position, the double-acting hydraulic actuator will be operated. Does not operate, and there is a problem that the double-acting hydraulic actuator cannot be fully operated up to the operation limit position.

Incidentally, such a problem is that the required power due to dynamic friction when the double-acting hydraulic actuator is decelerated and the double-acting hydraulic actuator is re-actuated after being stopped. Different from the required power due to static friction up to, and as described above, the hydraulic control valve has a structure in which the pump hydraulic pressure from the hydraulic pump is returned to the tank as it is in its neutral position, that is, a carryover oil passage is provided, In the transitional period from the neutral position of the hydraulic control valve to the predetermined switching position (that is, in the low speed control region described above), the pump hydraulic pressure is applied to both the oil supply and discharge passages to the double-acting hydraulic actuator and the tank oil passage. This is because the hydraulic pressure connected and supplied to the double-acting hydraulic actuator does not rise above the hydraulic pressure corresponding to the valve opening at that time.

On the other hand, if the double-acting hydraulic actuator is to be operated to the operation limit position in the above situation, the double-acting hydraulic actuator is once set to the operation limit position. Is operated in the opposite direction (i.e., in the direction in which the approach rate decreases and the operation of the double-acting hydraulic actuator is reflected on the safety side), the double-acting hydraulic actuator is at least approached. Return to a position where it is equal to or less than point b in FIG. 5 (that is, a position where the pilot signal value when operating to the operation limit position side is larger than the reference pilot signal value P ₂ ) and then the operation lever is moved to the operation limit position. However, the operation is complicated and time-consuming, and there is a problem in terms of operability.

Therefore, according to the present invention, even after the double-acting hydraulic actuator is temporarily stopped immediately before the operating limit position, the double-acting hydraulic actuator can be re-actuated toward the operating limit position side again. By doing so, the performance of the double-acting hydraulic actuator can be used as much as possible in relation to the operation limit position to improve its performance, and unnecessary operation can be omitted to improve its operability. The present invention is made to provide an automatic stop device for the double-acting hydraulic actuator.

[0010]

As a concrete means for solving such a problem in the invention of the present application, in the invention of claim 1, as shown in FIG. 1, a carry for connecting pump oil pressure to a tank oil passage. A neutral position 3A in which the over oil passage is opened and a pair of control ports are cut off, and a switching position in which the pump oil passage and the tank oil passage are connected to the corresponding pair of control ports and the carry over oil passage is cut off 3B, 3C, and a low speed control region in which the connection of the pump oil passage and the tank oil passage to the corresponding control oil passage is gradually increased and the carryover oil passage is narrowed between the neutral position 3A and the switching positions 3B, 3C. 3D, 3E
A four-way three-position spring center type hydraulic control valve 3 which is equipped with
And a manual pilot corresponding to the tilt operation amount from the neutral position of the operation lever 18 so that the hydraulic control valve 3 is switched according to the tilt operation amount from the neutral position of the operation lever 18. A manual pilot signal generator 15 for outputting a signal to the hydraulic control valve 3 and a compound pilot oil supply / discharging unit via which hydraulic oil is supplied / discharged via a pair of oil supply / discharge passages connected to the pair of control ports of the hydraulic control valve 3. An automatic stop device for a double-acting hydraulic actuator for automatically stopping the operation of the double-acting hydraulic actuator (1) at a predetermined operation limit position in a hydraulic control device including the dynamic hydraulic actuator 1. Operation limit position signal output means 12 for outputting a signal relating to the above-mentioned operation limit position of the dynamic oil pressure actuator 1, and work which becomes a factor for restricting the operation of the above double-acting hydraulic actuator (1). Working state detecting means 1 for detecting the state
1, the operation limit position signal output means 12 or the work state detection means 11 or the output signals from both the operation limit position signal output means 12 and the work state detection means 11, the operation direction from the operation limit position. Braking area signal output means 13 for outputting a braking area signal related to the braking area of the double-acting hydraulic actuator 1 set on the front side of the
And an actual value detecting means (14) for detecting an actual value related to the current operating state of the double acting hydraulic actuator (1),
The braking area signal output from the braking area signal output means 13 and the actual value detecting means 14 are provided in the transmission path of the pilot signal from the manual pilot signal generating means 15 to the hydraulic control valve 3. The upper limit of the pilot signal transmitted to the hydraulic control valve 3 when it is determined that the current operating state of the double-acting hydraulic actuator 1 has reached the braking range based on the actual value,
Immediately before the operating state of the double-acting hydraulic actuator 1 reaches a state corresponding to its operating limit position, the double-acting hydraulic actuator 1 is placed in the middle of the low speed control regions 3D, 3E and the carry-over oil passage. Is gradually reduced so as to be set to a value sufficient to operate up to a predetermined amount, and when the operating state of the double-acting hydraulic actuator 1 reaches a state corresponding to the operating limit position, the hydraulic pressure It is characterized in that a pilot signal upper limit regulating means 16 for regulating the control valve 3 to a neutral position 3A is provided.

According to the second aspect of the present invention, as illustrated in FIG. 3, the neutral position 3A in which the carryover oil passage connecting the pump oil pressure to the tank oil passage is opened and the pair of control ports are shut off, and the pump Switching positions 3B and 3C for connecting the oil passages and the tank oil passages to the corresponding pair of control ports, respectively, and for shutting off the carryover oil passages.
And the low-speed control regions 3D, 3E for gradually increasing the connection of the pump oil passage and the tank oil passage to the corresponding control oil passages and narrowing down the carryover oil passages from the neutral position 3A to the switching positions 3B, 3C. And a four-way three-position type spring center type hydraulic control valve 3 which is switched by a pilot signal, and an operating lever 18, which corresponds to the tilting operation amount from the neutral position of the operating lever 18 The manual pilot signal generator 15 for outputting to the hydraulic control valve 3 a manual pilot signal corresponding to the tilting operation amount from the neutral position of the operating lever 18 so that the hydraulic control valve 3 is switched, and the hydraulic control valve 3 A hydraulic control device comprising a double-acting hydraulic actuator 1 for supplying / discharging hydraulic oil via a pair of oil supply / drain passages connected to the pair of control ports. What is claimed is: 1. A double-acting hydraulic actuator automatic stop device for automatically stopping the operation of a dynamic hydraulic actuator (1) at a predetermined operating limit position, wherein a signal relating to the operating limit position of the double-acting hydraulic actuator 1 is transmitted. The operation limit position signal output means 12 for outputting, the work state detection means 11 for detecting a work state which is a factor for restricting the operation of the double-acting hydraulic actuator 1, the operation limit position signal output means 12 or the work state. The detection means 11 or the operation limit position signal output means 12 and the work state detection means 1
Braking area signal output means 13 for outputting a braking area signal relating to the braking area of the double-acting hydraulic actuator 1 set on the front side in the operation direction from the operation limit position based on the output signals from both , An actual value detecting means 14 for detecting an actual value related to the current operating state of the double-acting hydraulic actuator 1, and the pump hydraulic pressure directly returned to the tank oil passage to the control port of the hydraulic control valve 3. Hydraulic oil supply blocking means 31, 32 for blocking the supply of hydraulic oil and the transmission path of the pilot signal from the manual pilot signal generating means 15 to the hydraulic control valve 3, and the braking area signal output means 13 In the state where the present operating state of the double-acting hydraulic actuator 1 reaches the braking range based on the braking range signal output from the actual value detecting means 14 and the actual value output from the actual value detecting means 14. If it is determined that the upper limit value of the pilot signal transmitted to the hydraulic control valve 3 is set to the above-mentioned value just before the operating state of the double-acting hydraulic actuator 1 reaches the state corresponding to its operating limit position. Pilot signal upper limit regulation for gradually reducing the dynamic hydraulic actuator 1 to a value sufficient to operate in the middle of the low speed control regions 3D, 3E and until the carryover oil passage is narrowed down to a predetermined amount or more. Based on the means 16, the actual value output from the actual value detection means 14, and the operation limit position signal output from the operation limit position signal output means 12, the operating state of the double-acting hydraulic actuator 1 is as described above. When the state corresponding to the operation limit position is reached, the hydraulic oil supply blocking means 31, 32 are used to block the hydraulic oil supply to the control port of the hydraulic control valve 3. It is characterized in that a stop control unit 17.

[0012]

With each of the inventions of the present application, the following effects can be obtained by adopting such a configuration.

According to the first aspect of the present invention, when the operating state of the double-acting hydraulic actuator 1 reaches the braking area when the double-acting hydraulic actuator 1 is operated toward the limit position side. As long as the operating state of the double-acting hydraulic actuator continues to move toward the operation limit position side, the deceleration control is started from that point, and the upper limit value of the pilot signal changes from the pilot signal value at that point to the compound signal. The pilot signal value immediately before the operating state of the dynamic hydraulic actuator 1 reaches the state corresponding to its operating limit position, that is, the double-acting hydraulic actuator 1 is set in the low speed control regions 3D, 3E of the hydraulic control valve 3. The double-acting hydraulic actuator is regulated gradually so that the pilot signal value is set to a value sufficient for operation on the way and until the carry-over oil passage is narrowed down to a predetermined amount or more. 1 is slowed down gradually. Then, when the operating state of the double-acting hydraulic actuator 1 reaches the state corresponding to the operating limit position, the pilot signal value is restricted to a value capable of setting the hydraulic control valve 3 to the neutral position 3A, The supply of pump hydraulic pressure to the double-acting hydraulic actuator 1 is completely stopped, and the double-acting hydraulic actuator 1 is stopped at that time.

The above is the case where the operator continues to operate the operating lever 18 until the operating state of the double-acting hydraulic actuator 1 reaches the state corresponding to the operating limit position, but unlike this, the operator performs deceleration control. When the operation lever 18 is
Back to the neutral position and artificially double-acting hydraulic actuator 1
When the operation of the double acting hydraulic actuator 1 is operated again toward the operation limit position side by operating the operation lever 18 again, the upper limit value is set by the pilot signal upper limit value regulating means 16. The pilot signal value at the time of the temporary stop when the hydraulic pressure is regulated is always the double-acting hydraulic actuator 1 in the low speed control region 3 of the hydraulic control valve 3.
Since the pilot signal value is equal to or larger than the pilot signal value sufficient to operate in the middle of D and 3E and until the carry-over oil passage is narrowed down to a predetermined amount or more, the operation lever 18
As soon as is re-operated, the re-operation is started toward the operation limit position side, and finally the hydraulic control valve 3 is automatically set to the neutral position 3A at this operation limit position as in the above case. It is what is done.

According to the second aspect of the invention, basically the same operation as described above is performed except for the following points. That is, in the above-described invention according to claim 1, both the deceleration control in the braking region and the stop control in the operation limit position regulate the upper limit value of the pilot signal transmitted to the hydraulic control valve 3, thereby performing the hydraulic control. In contrast to the case where the function of the valve 3 is used, in the invention according to claim 2, the deceleration control in the braking region is to regulate the upper limit value of the pilot signal transmitted to the hydraulic control valve 3. Although done in
The stop control at the operation limit position is performed by the hydraulic oil supply blocking means 31,
32, the pump oil pressure is directly returned to the tank oil passage to prevent the supply of hydraulic oil to the control port of the oil pressure control valve 3.

[0016]

Therefore, according to the automatic stop device of the double-acting hydraulic actuator of the present invention, the double-acting hydraulic actuator is provided.
When the deceleration control of the double-acting hydraulic actuator 1 is being performed as the operating state of the actuator 1 approaches the state corresponding to the operating limit position, the operating lever 18 is once moved to the neutral position immediately before the operating limit position. Back to double-acting hydraulic actuator 1
When the operation lever 18 is operated again in the same direction after stopping the operation of, the double-acting hydraulic actuator 1 immediately resumes the operation to the operation limit position side and reaches the operation limit position. Then, since it is surely stopped, the double-acting hydraulic actuator 1 can be actuated to the operation limit position more quickly by a simple and convenient operation. For example, as in the conventional case, the double-acting hydraulic actuator 1 can be operated immediately before the operation limit position. Hydraulic actuator 1
Once the operation is stopped, the operability is improved as compared with the case where the double-acting hydraulic actuator 1 can be re-operated to the operation limit position side only after being operated in the opposite direction. The effect that the capacity of the double-acting hydraulic actuator 1 can be used more effectively is obtained.

[0017]

EXAMPLES The present invention will be specifically described below based on examples.

First Embodiment FIG. 1 shows a system diagram of an automatic stop device for a double-acting hydraulic actuator according to an embodiment of the invention described in claim 1 of the present application. In this embodiment, for example, a double-acting hydraulic actuator 1 such as a boom turning hydraulic motor of a boom crane is automatically stopped at an operation limit position defined by various conditions. A control oil passage 41, 42 for supplying / discharging hydraulic oil to / from the double-acting hydraulic actuator 1 and a pump oil passage 43 for supplying the pump oil pressure discharged from the hydraulic pump 2 to the control oil passage 41, 42 side. A hydraulic control valve 3 described later is arranged between them.

The hydraulic control valve 3 is composed of a four-way three-position type spring center type directional control valve, which opens the carry-over oil passage for connecting the pump oil pressure to the tank oil passage 44 and opens a pair of control ports. Neutral position 3 to shut off
A and the pump oil passage 43 and the tank oil passage 44 are connected to the corresponding pair of control ports, respectively, and in addition to the three valve positions of the switching positions 3B and 3C for shutting off the carryover oil passage, the neutral position. Each switching position 3 from 3A
As a transitional stage to B, 3C, low speed control regions 3D, 3E are set in which the connection of the pump oil passage 43 and the tank oil passage 44 to the corresponding control oil passages 41, 42 is gradually increased and the carryover oil passage is narrowed down. ing. The switching of the hydraulic control valve 3 is performed by a pilot signal given as a voltage signal so that the spool movement amount from the neutral position, that is, the flow rate is increased or decreased in proportion to the pilot signal value (voltage value). It has become. That is, when the maximum pilot signal value is input, the hydraulic control valve 3 is completely switched from the neutral position 3A to any of the switching positions 3B and 3C, and the input of the pilot signal is blocked, so that the neutral position 3A is blocked. When the pilot signal value is between 0 and the maximum value, it is located in the low speed control areas 3D and 3E and its opening is proportional to the magnitude of the pilot signal value.

The pilot signal transmitted to the hydraulic control valve 3 is basically output from the manual pilot signal generating means 15 according to the operating direction and the tilting operation amount when the operator operates the operation lever 18. However, the pilot signal output from the manual pilot signal generating means 15 is corrected based on various factors such as the working state or the operating state of the double-acting hydraulic actuator 1, its value, the output timing, etc. Therefore, the automatic stop of the double-acting hydraulic actuator 1 and the improvement of the operability associated with the automatic stop control, which are the objects of the present invention, are achieved. In order to realize this, in this embodiment, a work state detecting means 11, an operation limit position signal outputting means 12, a braking area signal outputting means 13, an actual value detecting means 14 and a pilot signal upper limit regulating means 16 described later are provided. I have it.

The work state detecting means 11 detects a work state which is a factor for restricting the operation of the double-acting hydraulic actuator 1, and for example, the double-acting hydraulic actuator 1 is connected to a hydraulic crane. When using a hydraulic motor for swinging the boom, information related to the tipping moment of the crane, that is, the swing angle of the boom, boom extension / contraction length, boom up / down angle, outrigger overhang, etc., and surrounding work conditions. Set signal input by the operator according to (for example, a signal corresponding to the distance between the structure and the crane when there is a structure with a risk of collision with the boom)
Etc. correspond to this. Then, each of these pieces of information is constantly detected by the work state detecting means 11, and is output to the operation limit position signal output means 12 or the braking area signal output means 13 described later as needed.

The operation limit position signal output means 12 receives the work state signal from the work state detecting means 11,
It outputs a signal regarding the operation limit position of the double-acting hydraulic actuator 1 (that is, the boom) under the present working condition. As the operation limit position signal, for example, the limit turning position of the boom corresponding to the limit moment value allowed from the falling moment of the crane, or the collision of the boom with other structures based on the set signal input by the operator. The maximum turning position that can be prevented is considered. The double-acting hydraulic actuator 1 is automatically stopped at the operation limit position based on the operation limit position signal output from the operation limit position signal output means 12.

The braking area signal output means 13 outputs a signal related to the braking area for decelerating the double-acting hydraulic actuator 1 from the viewpoint of shock mitigation, etc., before automatically stopping the double-acting hydraulic actuator 1 at the operation limit position. As shown in FIG. 4, the braking area is a predetermined range on the front side of the operation limit position (for example, the approach rate to the operation limit position is 100% to 100%).
90% range). In this case, the braking area signal in the braking area signal output means 13 is set based on the operation limit position signal from the operation limit position signal output means 12 with respect to the operation limit position as a reference, and is set to the front side by a certain area. On the basis of the work state signal from the work state detecting means 11, when the inertia force when the boom is stopped is large, such as when the boom length is long or when the turning speed is high, the tipping moment or the set signal is used. It is conceivable that the more required braking area is corrected and set more widely, or it is set based on both signals. Which of these setting methods should be adopted depends on various working conditions and the like. The actual value detecting means 14 determined in consideration of the circumstances is related to the current operating state of the double-acting hydraulic actuator 1. Saine, for example, double acting hydraulic actuator - the operation of motor 1 (i.e.,
The moment value of the crane that changes with the turning of the boom) and the current operating position of the double-acting hydraulic actuator 1.
Although the present turning position of the boom may be considered, in this embodiment, as described above, the braking area is defined by the proximity rate to the operation limit position, that is, the distance between the operation limit position and the boom. Therefore, the current turning position of the boom is output here as an actual value.

The pilot signal upper limit value regulating means 16 is based on the braking area signal output from the braking area signal output means 13 and the actual value output from the actual value detecting means 14, and is based on the manual pilot signal generating means 15 described above. The upper limit value of the manual pilot signal output corresponding to the operation tilting amount of the operation lever 18 is appropriately regulated and transmitted to the hydraulic control valve 3 side, and the regulation characteristic is the characteristic shown in FIG. It is set as shown in FIG. L ₁ or the L _2. That is, in the case of the characteristic diagram L ₁ , the pilot signal value is P ₁ when the operation tilt amount of the operation lever 18 is maximum (that is, at the maximum operating speed), and the pilot signal value immediately before the operation limit position is P ₂ The pilot signal value is linearly gradually reduced from the value P ₁ to the value P ₂ in the range of the braking area. In the case of the characteristic diagram L _2, the pilot signal value P ₂ is maintained only in the predetermined range (the range from the operation limit position to the point c) from the operation limit position to the front side, and the point c from the braking start point to the above point c
In the range up to, the pilot signal value is gradually changed from P ₁ to P ₂ . And in either case,
At the operating limit position, the pilot signal value is set to zero.

Incidentally, the value of the pilot signal value P ₂ immediately before the operation limit position corresponds to the reference pilot signal value already explained with reference to FIG. 5, and the hydraulic control valve 3 is in the low speed control region and carry. The value is set such that the minimum oil pressure sufficient to restart the double-acting hydraulic actuator 1 by operating the over oil passage to a state in which it is throttled by a predetermined amount or more is generated. Further, in this embodiment, the regulation characteristic of the upper limit value of the pilot signal is set in the characteristic diagram L ₁ or L ₂ , but the invention of the present application is not limited to this, and the point is that the deceleration control is performed. If the characteristic is such that it gradually decreases from the pilot signal value P ₁ at the start point to the pilot signal value P ₂ immediately before the actuation limit position and that a large shock is not accompanied when the actuation is stopped immediately before the actuation limit position, during that period. The restriction characteristic is not limited to the decreasing path of, and, for example, it is possible to adopt a regulation characteristic that changes in a curve from the pilot signal value P ₁ to the pilot signal value P ₂ .

Further, the regulation characteristic of the upper limit value is set on the basis of the case where the operation lever 18 is at the maximum operation amount as described above. Therefore, for example, when the operation tilt amount of the operation lever 18 is medium. 4 has characteristics as shown by the broken line in FIG. 4, and the point d in the case of the characteristic diagram L ₁ and the point e in the case of the characteristic diagram L ₂ are the starting points of the upper limit regulation. That is,
The braking area changes in accordance with the operation tilt amount of the operation lever 18 (in other words, according to the operating speed before the deceleration control of the double-acting hydraulic actuator 1 is started), and the direction of change is such that the operation tilt amount is large. It becomes wider as the operating speed becomes higher (that is, as the operating speed becomes higher), and this can be said to substantially take into consideration the influence of the inertial force of the boom in the setting of the braking area in the braking area signal output means 13. Further, when the operation tilt amount of the operation lever 18 is at the intermediate position as described above, the actual pilot signal value is smaller than the regulation value before the upper limit regulation of the pilot signal value is started. In this case, the actual pilot signal value is output in preference to the regulation value, and the double-acting hydraulic actuator 1 is operated at a speed corresponding to the operation tilting amount of the operating lever 18.

Next, the operation of the automatic stop device for the double-acting hydraulic actuator according to the present embodiment constructed as described above will be described with reference to the case where the double-acting hydraulic actuator 1 is operated at the maximum speed. A pilot signal for controlling the operation of the hydraulic control valve 3 is input from the manual pilot signal generating means 15 to the pilot signal upper limit regulating means 16 in accordance with the operation tilt amount of the operating lever 18. On the other hand, the work state detection means 11 outputs a work state signal related to the operation of the double-acting hydraulic actuator 1, and the operation limit position signal output means 12 outputs the double-acting hydraulic pressure based on the work state signal or the like. Actuator 1
The operation limit position is set and the operation limit position signal is output. Then, in the braking area signal output means 13,
A braking area for executing deceleration control of the double-acting hydraulic actuator 1 is set based on the operation limit position signal, etc., and a signal related to this braking area is a pilot signal upper limit value control means 16
Entered in. Furthermore, the actual turning position of the boom is input from the actual value detecting means 14 to the pilot signal upper limit value limiting means 16 as an actual value related to the current operation of the double-acting hydraulic actuator 1.

Then, the pilot signal upper limit value regulating means 1
In 6, the upper limit value regulation control of the pilot signal is executed based on the braking area signal from the braking area signal output means 13 and the actual value from the actual value detecting means 14. That is, it is determined whether or not the turning position of the boom has reached the braking area defined in relation to the operation limit position. If not, the upper limit regulation is not performed and the hydraulic control valve 3
The pilot signal value output from the manual pilot signal generating means 15 corresponding to the operation tilting amount of the operation lever 18 is transmitted to the hydraulic control valve 3 as it is. The switching position 3B or the other switching position 3C is set, and the double-acting hydraulic actuator is set.
The tool 1 rotates at a maximum speed in a predetermined direction to rotate the boom.

On the other hand, when it is determined that the turning position of the boom has reached the braking range, the upper limit of the pilot signal value from the manual pilot signal generating means 15 is set according to the regulation characteristic diagram L ₁ or L _{2 of} FIG. Even if the value is regulated and the operator holds the operating lever 18 at the maximum operating position, the pilot signal value transmitted to the hydraulic control valve 3 is gradually changed, and the hydraulic control valve 3 is gradually changed to its switching position 3B. , 3C to the low speed control area 3D. After shifting to 3E, the position gradually approaches the neutral position 3A. Therefore, the amount of oil supplied to the double-acting hydraulic actuator 1 gradually decreases, the rotational speed of the double-acting hydraulic actuator 1 gradually decreases, and the swinging motion of the boom is decelerated.

When the turning position of the boom reaches the operation limit position, the pilot signal value transmitted to the hydraulic control valve 3 becomes zero (that is, transmission of the pilot signal is stopped), and the hydraulic control valve 3 is in the neutral position. When set to 3A, the double-acting hydraulic actuator 1 is stopped at that point, which realizes automatic stop at the operation limit position of the boom. In this case, since the vehicle is sufficiently decelerated before reaching the operation limit position, the shock at the time of stopping is small.

On the other hand, during this deceleration control, when the operator intentionally returns the operating lever 18 to the neutral position at a position immediately before the operation limit position (for example, the position of point f in FIG. 4), the manual pilot signal Since the pilot signal output from the generating means 15 is stopped, the hydraulic control valve 3 is immediately set to the neutral position 3A from the valve position at that time, the double-acting hydraulic actuator 1 is deactivated, and the boom swings. Also stop. After the double-acting hydraulic actuator 1 is once stopped, when the operator again operates the operating lever 18 to turn the boom further toward the operation limit position side, the upper limit value by the pilot signal upper limit value regulating means 16 at that time point. Since the regulation condition of No. 1 is the same as that before the stop, the hydraulic control valve 3 is also reset to the valve position before the stop (that is, the predetermined position in the low speed control regions 3D and 3E). In this case, the pilot signal value P ₂ immediately before the operation limit position operates the hydraulic control valve 3 in the middle of the low speed control regions 3D and 3E and to the throttle position where the double-acting hydraulic actuator 1 can be re-activated from the stopped state. Since the pilot signal value is set to a sufficient value, the double-acting hydraulic actuator 1 is re-actuated toward the actuation limit position at the same time when the operation lever 18 is re-actuated, and finally reaches the actuation limit position. It is automatically stopped at.

Therefore, when the operation of the double-acting hydraulic actuator 1 is once stopped just before the operation limit position as in the conventional case, the operation lever 18 is once operated in order to re-operate it toward the operation limit position side. In the opposite direction, it is necessary to reverse the double-acting hydraulic actuator 1.
The operation is simple and quick, the operability is good, and the maximum capacity allowed in relation to the operation limit position of the double-acting hydraulic actuator 1 can be surely utilized.

Further, particularly when the upper limit value is regulated according to the regulation characteristic diagram L ₂ of FIG. 4, the pilot signal value P ₂ is maintained constant in a predetermined range immediately before the operation limit position. Even if the double-acting hydraulic actuator 1 is temporarily stopped at any position within this range, the shock caused by the stop can be suppressed to a small level, which contributes to the improvement of operational reliability. is there.

In this embodiment, the double-acting hydraulic actuator 1 is used as a boom-turning hydraulic motor of a hydraulic crane for automatic stop at the time of turning the boom. However, the present invention is not limited to this. Of course, for example, in a hydraulic crane, it can be applied to an automatic stopping device for a boom hoisting hydraulic cylinder, an automatic stopping device for a boom telescopic hydraulic cylinder, and the like.

Second Embodiment FIG. 2 shows an essential part of an automatic stop device for a double-acting hydraulic actuator according to an embodiment of the invention described in claim 1 of the present application. In this embodiment, the hydraulic control valve 3 of the first embodiment is an electromagnetic pilot type directional control valve, whereas it is a hydraulic pilot type directional control valve. The manual pilot signal generating means 15 and the pilot signal upper limit regulating means 16 in the first embodiment are constituted by a hydraulic circuit. That is, the pair of pilot hydraulic operation valves 22, 2 selectively operated by the operation lever 18
3 is connected to the discharge oil passage of the hydraulic pump 21 for generating the pilot oil pressure, and the oil pressure generated corresponding to the operation direction and the operation tilt amount of the operation lever 18 is supplied to the oil pressure control valve via the pilot oil passages 35 and 36. 3 to supply the hydraulic control valve 3
The switching control of is performed.

Further, in the middle of the pilot oil passages 35 and 36, the braking area signal output from the braking area signal output means 13 and the actual value detection means 14 (see FIG. 1) and the double-acting hydraulic actuator 1 are output. An electromagnetic proportional pressure reducing valve 24 and an electromagnetic switching valve 25, which are operated and controlled on the basis of the actual value signal, are arranged in parallel so that deceleration control and automatic stop of the double-acting hydraulic actuator 1 can be performed respectively. That is, in this embodiment, each of the pilot hydraulic operation valves 2
The pilot hydraulic pressures generated by the hydraulic pressure control valves _{2 and} 23 are pressure-reduced according to the regulation characteristic diagram L ₁ or L _{2 of} FIG. -While gradually decreasing the operating speed of the motor 1, when the operating limit position is reached, the electromagnetic switching valve 25 is opened to extinguish the pilot hydraulic pressure and return the hydraulic control valve 3 to the neutral position 3A to perform the double-acting operation. The hydraulic actuator 1 is stopped. Therefore, also in this embodiment, the same operational effect as in the case of the first embodiment can be obtained.

In this embodiment, each of the pilot hydraulic pressure operating valves 22 and 23 constitutes the manual pilot signal generating means 15 in the first embodiment, and the electromagnetic proportional pressure reducing valve 24 and the electromagnetic switching valve 25 are the first. It constitutes the pilot signal upper limit value regulating means 16 in one embodiment. Also, FIG.
Although not shown in the figure, it goes without saying that the working state detecting means 11, the operation limit position signal outputting means 12 and the braking area signal outputting means 13 in the first embodiment are also provided in this embodiment.

Further, in this embodiment, as the pilot signal upper limit value control means 16, an electromagnetic proportional pressure reducing valve 24 for performing deceleration control and an electromagnetic switching valve 25 for performing stop control are provided. However, in other embodiments. Even if only the electromagnetic proportional pressure reducing valve 24 is provided as the pilot signal upper limit regulating means 16 and the electromagnetic proportional pressure reducing valve 24 is configured to be unloaded at the operation limit position, the same operational effect can be obtained.

Third Embodiment FIG. 3 shows an automatic stop device for a double-acting hydraulic actuator according to the second embodiment of the present invention.
In this embodiment, in the first embodiment, the deceleration control of the double-acting hydraulic actuator 1 and the stop control at the operation limit position are both achieved by the operation control of the hydraulic control valve 3. On the other hand, only the deceleration control of the double-acting hydraulic actuator 1 is performed by the operation control of the hydraulic control valve 3, and the stop control at the operation limit position is performed by electromagnetically controlling the vent port of the relief valve 31 provided in the pump oil passage 43. The switching valve 32 is arranged, the vent port is opened, and the pump oil pressure is directly returned to the tank side. Therefore, in this embodiment, stop control means 17 for outputting a pilot signal to the electromagnetic switching valve 32 at the operation limit position is added to the structure of the first embodiment.

Also in this embodiment, similarly to the first embodiment, the deceleration control of the double-acting hydraulic actuator 1 and the stop control at the operation limit position are performed, and the double-acting hydraulic actuator is also operated. It is needless to say that the re-operation after once stopping 1 at the position just before the operation limit position can be restarted as it is by the re-operation of the operation lever 18, and the operability and the like can be improved.

[Brief description of drawings]

FIG. 1 is an overall system diagram of an automatic stop device for a double-acting hydraulic actuator according to a first embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of a main part of an automatic stop device for a double-acting hydraulic actuator according to a second embodiment of the present invention.

FIG. 3 is an overall system diagram of an automatic stop device for a double-acting hydraulic actuator according to a third embodiment of the present invention.

FIG. 4 is a control characteristic diagram of a pilot signal in the automatic stop device for a double-acting hydraulic actuator of the present invention.

FIG. 5 is a control characteristic diagram of pilot signals in a conventional automatic stop device for a double-acting hydraulic actuator.

[Explanation of symbols]

1 is a double-acting hydraulic actuator, 2 is a hydraulic pump, 3 is a hydraulic control valve, 11 is a working state detecting means, 12 is a stop position signal outputting means, 13 is a braking area signal outputting means, 14 is an actual value detecting means, 15 is a manual pilot signal generating means, 16
Is a pilot signal upper limit regulating means, 17 is a stop control means, 18 is an operating lever, 21 is a hydraulic pump, 22 is a pilot hydraulic operating valve, 23 is a pilot hydraulic operating valve, 24
Is an electromagnetic proportional pressure reducing valve, 25 is an electromagnetic switching valve, 31 is a relief valve, and 32 is an electromagnetic switching valve.

Claims (2)

[Claims] 1. A neutral position (3A) in which a carry-over oil passage connecting pump oil pressure to a tank oil passage is opened and a pair of control ports are shut off, and the pair of pump oil passages and tank oil passages respectively corresponding to each other. Switching position to connect to the control port of and to cut off the carry-over oil passage
(3B, 3C) and the switching position (3
(B, 3C) is provided with a low-speed control area (3D, 3E) that gradually increases the connection of the pump oil passage and the tank oil passage to the corresponding control oil passage and narrows down the carryover oil passage. A four-way three-position type spring center type hydraulic control valve (3) that is switched by a signal and an operating lever (18) are provided to correspond to the tilting operation amount from the neutral position of the operating lever (18). A manual pilot signal generator (15) for outputting to the hydraulic control valve (3) a manual pilot signal corresponding to the amount of tilt operation from the neutral position of the operating lever (18) so that the hydraulic control valve (3) can be switched.
And a double-acting hydraulic actuator (1) for supplying / discharging hydraulic oil via a pair of oil supply / drain passages connected to the pair of control ports of the hydraulic control valve (3). A double-acting hydraulic actuator automatic stop device for automatically stopping the operation of the double-acting hydraulic actuator (1) at a predetermined operation limit position, the operation of the double-acting hydraulic actuator (1). Actuating limit position signal output means (12) for outputting a signal relating to the limit position
A work state detecting means (11) for detecting a work state which is a factor for restricting the operation of the double acting hydraulic actuator (1), and the operation limit position signal output means (12) or the work state detecting means ( 11) Or the operation limit position signal output means
Braking related to the braking area of the double-acting hydraulic actuator (1), which is set on the front side in the operating direction from the operating limit position based on the output signals from both (12) and the work state detecting means (11). Braking region signal output means for outputting a region signal
(13), actual value detecting means (14) for detecting an actual value related to the current operating state of the double-acting hydraulic actuator (1), and the hydraulic control from the manual pilot signal generating means (15). Based on the braking area signal output from the braking area signal output means (13) and the actual value output from the actual value detection means (14), which is interposed in the transmission path of the pilot signal to the valve (3) The upper limit of the pilot signal transmitted to the hydraulic control valve (3) when it is determined that the current operating state of the double-acting hydraulic actuator (1) has reached the braking range is Immediately before the operating state of the double-acting hydraulic actuator (1) reaches a state corresponding to its operating limit position, the double-acting hydraulic actuator (1) is moved in the middle of the low speed control region (3D, 3E) and The carryover oil passage is squeezed to a specified amount When the operating state of the double-acting hydraulic actuator (1) reaches a state corresponding to the operating limit position, the hydraulic control valve (3 ) To the neutral position
(3A) An automatic stop device for a double-acting hydraulic actuator, comprising: a pilot signal upper limit value regulating means (16) for regulating a value that can be compared. 2. A neutral position (3A) in which a carry-over oil passage connecting pump oil pressure to a tank oil passage is opened and a pair of control ports are shut off, and the pair of pump oil passage and tank oil passage respectively corresponding to the neutral position. Switching position to connect to the control port of and to cut off the carry-over oil passage
(3B, 3C) and the switching position (3
(B, 3C) is provided with a low-speed control area (3D, 3E) that gradually increases the connection of the pump oil passage and the tank oil passage to the corresponding control oil passage and narrows down the carryover oil passage. A four-way three-position type spring center type hydraulic control valve (3) that is switched by a signal and an operating lever (18) are provided to correspond to the tilting operation amount from the neutral position of the operating lever (18). A manual pilot signal generator (15) for outputting to the hydraulic control valve (3) a manual pilot signal corresponding to the amount of tilt operation from the neutral position of the operating lever (18) so that the hydraulic control valve (3) can be switched.
And a double-acting hydraulic actuator (1) for supplying / discharging hydraulic oil via a pair of oil supply / drain passages connected to the pair of control ports of the hydraulic control valve (3). A double-acting hydraulic actuator automatic stop device for automatically stopping the operation of the double-acting hydraulic actuator (1) at a predetermined operation limit position, the operation of the double-acting hydraulic actuator (1). Actuating limit position signal output means (12) for outputting a signal relating to the limit position
A work state detecting means (11) for detecting a work state which is a factor for restricting the operation of the double acting hydraulic actuator (1), and the operation limit position signal output means (12) or the work state detecting means ( 11) Or the operation limit position signal output means
Braking related to the braking area of the double-acting hydraulic actuator (1), which is set on the front side in the operating direction from the operating limit position based on the output signals from both (12) and the work state detecting means (11). Braking region signal output means for outputting a region signal
(13), an actual value detecting means (14) for detecting an actual value related to the current operating state of the double-acting hydraulic actuator (1), and the pump hydraulic pressure is directly returned to the tank oil passage to Hydraulic oil supply blocking means (31, 32) for blocking the supply of hydraulic oil to the control port of the hydraulic control valve (3), and a pilot from the manual pilot signal generating means (15) to the hydraulic control valve (3). The double-acting hydraulic actuator is installed in the signal transmission path and is based on the braking area signal output from the braking area signal output means (13) and the actual value output from the actual value detecting means (14). The upper limit of the pilot signal transmitted to the hydraulic control valve (3) when it is determined that the current operating state of (1) has reached the braking range is the double-acting hydraulic actuator ( The operating state of 1) reaches the operating limit position. Immediately before the operation, the double-acting hydraulic actuator (1) is set to a value sufficient to operate in the middle of the low speed control area (3D, 3E) and until the carryover oil passage is narrowed down to a predetermined amount or more. A pilot signal upper limit regulating means (16) for gradually reducing the regulation, an actual value output from the actual value detecting means (14), and an operation limit position signal output from the operation limit position signal output means (12). Based on the above, the double-acting hydraulic actuator
When the operating state of (1) reaches the state corresponding to the operating limit position, the operating oil supply blocking means (31, 32) is used to supply the operating oil to the control port of the hydraulic control valve (3). An automatic stop device for a double-acting hydraulic actuator, comprising: stop control means (17) for blocking.