KR910004035B1 - Control apparatus of hydraulic winch - Google Patents

Abstract

No content.

Description

Hydraulic pressure control device

1 and 2 are circuit diagrams and output characteristics diagrams of a conventional apparatus.

3 is a circuit diagram of the present invention.

4 is a control characteristic diagram of the hydraulic motor and other valves.

5 is a circuit diagram of another embodiment.

* Explanation of symbols for main parts of the drawings

20: hydraulic source 22,22A: direction switching valve

22a, 50: Control valve 20.24A: Hydraulic motor

30,30: Hydraulic cylinder as a regulator 34: Oil loss

36,38: check valve as a high pressure selection valve

40, 40A: Pressure reducing valve as control valve 42: Cam mechanism

The present invention relates to a control device applied to a hydraulic pressure source that changes the capacity of a variable displacement hydraulic motor in response to a change in load to have a substantially constant horsepower output characteristic.

Background Art Hydraulic pressure sources that increase or decrease the capacity of a variable displacement hydraulic motor for driving a primary drum in response to a load increase or decrease and obtain almost constant horsepower output characteristics have conventionally been known. In this principle, low speed and large torque are obtained at high loads, and high speed and small torque control characteristics are obtained at light loads.

Although this kind of raw material is shown in the prior art in Japanese Patent Application Laid-Open No. 58-52196, it has a circuit configuration shown in FIG. 1 and control characteristics shown in FIG. 2, and the hydraulic pressure of the hydraulic source 1 of FIG. It is supplied to the variable displacement hydraulic motor 2 via the direction switching valve 3, and the volume of the hydraulic motor 2 is controlled by the hydraulic cylinder 4. As shown in FIG. Denoted at 5 is a constant horsepower control valve, the pressure of the high pressure selection valve 6 is delivered to the piston 7 so that the pressure of the high pressure selection valve 6 is balanced with the pressure of the compression spring 8. In the hoisting position (a) of the switching valve (3), the hydraulic oil of the hydraulic pressure source (1) passes through the check valve (9) of the counterweight valve (9), the high pressure selection valve (6), and the piston (7) and the sprue ( 10) is moved upward and downward in the drawing. As a result, the pressure of the high pressure selection valve 6 is led to the large chamber 4a of the cylinder 4, so that the volume of the motor 2 increases to become the volume corresponding to the load. Since the pressure applied to the piston 7 increases in response to the load of the motor 2, the motor 2 becomes a large capacity at the time of heavy load, and the motor 2 becomes low speed and large torque at this time. That is, the constant horsepower characteristic indicated by the hyperbola of FIG. 2 is obtained.

In the conventional apparatus configured as described above, if the switching valve 3 is in a neutral position and the pressure is selected as the low pressure of the high pressure selection valve 6, the sprue 10 is pushed to the left by the spring 8 and the high pressure selection valve (6) communicates with the chamber 4b of the cylinder 4, and the cylinder 4a of the cylinder 4 communicates with the tank of the hydraulic source 1 via the spun 10, so that the cylinder 4 Move to the left in the figure. That is, the motor 2 is made into the minimum volume. In this state, the motor 2 is at the position of the minimum torque, and is in a state where the maximum speed can be achieved if the oil supply amount is constant.

For this reason, even if the switching valve 3 is controlled to start the motor 2 at a small load, the ratio of the rotation speed change of the motor 2 to the operation amount of the switching valve 3 is large, so that the motor 2 It rotates at a high speed in a timely manner, which causes a problem that microspeed control becomes very difficult. In the case where the load is suspended in the air, when the switching valve 3 is in the neutral position, the capacity of the hydraulic motor 2 is equivalent to that of the load. There was also a problem that the falling amount inversely proportional to the power of 2 was larger than the case where the hydraulic motor 2 reached the maximum capacity. In other words, there is a problem that the speed of the original speeds up against the operator's intention.

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention has a first object to provide a control device for a hydraulic pressure source capable of stably performing slow speed control at the time of starting a motor. In addition, it is possible to provide a hydraulic pressure control device capable of improving the handling performance by enabling the speed control according to the operator's intention without increasing the original speed against the operator's intention when the load suddenly decreases. The purpose.

The first object of the present invention is achieved by controlling the hydraulic motor to have a maximum capacity within a predetermined operating range near the neutral position of the control lever for controlling the directional control valve. In other words, the first object is to connect a variable displacement hydraulic motor and a hydraulic pressure source for driving the unwanted drum through a directional valve, and change the capacity of the hydraulic motor in response to the load by means of a regulator. And a control valve for operating the regulator so as to maximize the hydraulic motor within a predetermined operating range near the neutral position of the control lever controlling the directional control valve in the hydraulic pressure source. .

The second object is a regulator which increases or decreases by increasing or decreasing the load of the hydraulic motor by adding a function of reducing the automatic pressure of the regulator in response to the increase in the operation amount of the control lever above the predetermined operating range of the control lever. By operating the regulator in the direction of increasing the hydraulic motor capacity by the regulator operating pressure on any high pressure side between the operating pressure and the regulator operating pressure determined by the regulating lever. That is, the capacity of the hydraulic motor is controlled to be any larger capacity between the capacity determined by the increase and decrease of the load and the capacity determined by the operation amount of the control lever.

Hereinafter, the present invention will be described in detail by way of examples.

The following example is an example using hydraulic pressure as hydraulic pressure.

3 is a circuit diagram of one embodiment, and FIG. 4 is a control characteristic diagram of a hydraulic motor and other valves. In FIG. 3, 20 is a four-port, three-position ABR connection manually switching valve, 24 is a variable displacement hydraulic motor, which is connected to circulate oil, which is a working fluid. The direction switching valve 22 has an throttling valve, and when the operating angle θ of the control lever is small between θ ₃ and θ ₁ , the flow rate becomes almost proportional to θ and the flow rate becomes constant when θ becomes larger than this range. It has adjustment characteristics (Fig. 4). An external pilot type flow regulating valve 26 is connected between the discharge port of the hydraulic source 20 and the P port of the switching valve 22, and the flow regulating valve 26 is formed by the A and B of the switching valve 22. It is operated by the pressure difference between the hydraulic pressure delivered from the high pressure selection valve 27 connected between the oats and the hydraulic pressure immediately after the flow control valve 26, and at a certain flow rate, it is almost constant despite the change of the load condition applied to the original value. The flow rate is supplied to the hydraulic motor 24.

(28) is an external pilot type counterweight valve, which is connected between the oil inlet at the time of hoisting of the motor 24 and the A port of the switching valve 22, so that it can be unloaded at a stable speed under the load. Works. The pilot pressure of this counterweight valve 28 is taken out from the oil outlet when the motor 24 is hoisted.

30 generates a driving force for controlling the capacity of the hydraulic motor 24 as a hydraulic cylinder as a regulator. This cylinder 30 is provided with the returning wetness to the direction which makes the motor 24 minimum capacity by the compression coil spring 32, and raises the capacity | capacitance of the motor 24 by raising the internal pressure of the oil chamber 34. As shown in FIG. Increase. The high pressure side of the inlet and outlet of the motor 24 is supplied to the oil chamber 34 through the check valves 36 and 38 as the high pressure selection valve as the regulator operating pressure.

40 is a hydraulic pressure reducing valve as a control valve interposed between the discharge side of the hydraulic source 20 and the oil chamber 34, and the output pressure of the pressure reducing valve 40 is a direction switching valve via the cam mechanism 42. In conjunction with (22), the conversion is performed as in the fourth degree.

That is, within the predetermined operating range of θ ₁ -θ ₃ near the neutral position of the switching valve 22, the hydraulic oil of the hydraulic source 20 is guided to the oil chamber 34 to the maximum capacity of the motor 24, and the switching valve ( As the operating angle θ of 22) increases beyond this θ ₁ -θ ₃ , the decompression amount increases, and this pressure is supplied to the oil chamber 34 as a regulator operating pressure determined by the control lever.

Reference numeral 44 denotes a flow control valve with a check valve, and the check valve 44a interposed between the pressure reducing valve 44 and the oil chamber 34 and inserted into the flow control valve 44 is the check valve 36. (38), in conjunction with the regulator operating pressure determined by the load and the regulator operating pressure determined by the control lever, is guided to the oil chamber 34 to determine the capacity of the motor 24.

Next, the operation will be described. First, when the operating angle θ of the control lever 22a is 0, the switching valve 22 is in a neutral position, and the pressure oil of the hydraulic pressure source 20 flows into the oil chamber 34 through the pressure reducing valve 40 and the check valve 44a. Is delivered. At this time, since the pressure generated by the pressure reducing valve 40 is sufficiently higher than the pressure required to maintain the hydraulic motor 29 at the maximum capacity, the hydraulic motor 24 has a maximum capacity. The pressure generated by the pressure reducing valve 40 maintains the capacity of the hydraulic motor 24 to the maximum. The operating angle θ of the control lever 22a is between θ ₁ and θ ₃ , and the hydraulic motor 24 is in this range. ) Is always fixed at maximum capacity. For this reason, even when the load is suspended in the air when the operating angle θ is 0 °, that is, when the switching valve 22 is neutral, the drop amount of the load for the same load is minimized, and the hydraulic source is stopped in the most stable state. You lose.

Furthermore, since the operating capacity θ of the control lever 22a is θ ₁ -θ ₃ , the capacity of the hydraulic motor 24 is maximum and does not change, so that the speed of the hydraulic motor 24 passes through the switching valve 22. Proportional to the liquid level. In other words, if the flow rate passing through the switching valve 22 is approximately proportional to the operating angle θ within the operating range of θ ₁ -θ ₃ of the control lever 22a, the speed of the original value is determined by the operating angle θ of the control lever 22a. It is delicately controlled and fine speed control is performed stably. The 1st object of this invention is achieved as mentioned above.

When the operating angle θ of the control lever 22a becomes large in the range of θ ₁ -θ ₃ , the pressure generated by the pressure reducing valve 40 is the loss of the regulator 30 of the regulator 30 of the hydraulic motor 24 as a regulator operation input. It acts on and returns to the pressure which reduces the capacity of the hydraulic motor 24.

That is, as the operation angle θ of the control lever 22a becomes large, the capacity of the hydraulic motor 24 becomes small. Therefore, the rotational speed of the hydraulic motor 24 increases with respect to the same feed liquid amount, and the speed of the original value also increases. On the other hand, the hydraulic pressure generated in the motor 24 due to the drop applied to the hydraulic motor 24 is inversely proportional to the capacity of the hydraulic motor 24 when the hydraulic load is the same load, so that the operating angle θ of the control lever is greatly increased. As the capacity of the hydraulic motor 24 is reduced, the oil pressure generated by the load increases.

When the hydraulic pressure at this time is higher than the pressure generated by the pressure reducing valve 40, the high pressure side pressure selected by either the check valve 36 or 38 is directed to the oil chamber 34 as a regulator operating pressure, and the hydraulic motor 24 ) Is determined by the load in preference to the operating angle θ of the control lever 22a. Therefore, at this time, the speed is determined by the load and becomes a substantially constant horsepower output characteristic as shown in FIG.

In other words, in the control circuit of the hydraulic pressure value, the regulator operating pressure generated by the pressure reducing valve 40 is given priority to determine the capacity of the hydraulic motor 24, so that the original speed is adjusted regardless of the load variation. Can be stabilized.

In addition, in the other range, that is, the range in which the regulator operating pressure generated by the load in the hydraulic motor 24 takes precedence, almost constant horsepower output characteristics are obtained.

In this way, the speed control of the original value is stabilized, the controllability and the workability are improved, and the second object of the present invention is achieved.

In FIG. 4, for convenience, the flow control range (θ ₁ -θ ₃ ) of the switching valve 22 and the hoisting and hoisting ranges of the original value (θ ₁ -θ ₂ , θ ₃ -θ ₄ ) are shown as θ ₁ and θ _3. In the present invention, the present invention does not matter whether the two control ranges overlap or fall, and such cases are included.

5 is a circuit diagram of another embodiment of the present invention, in which the direction switching valve 22A and the hydraulic pressure reducing valve 40A are hydraulically controlled by the control lever 50. As shown in FIG. That is, when the lever 50 is turned to the right from the neutral position in the figure, the switching valve 22A moves to the right, and the hydraulic motor 24A rotates in the lifting direction. At this time, if the operation of the lever 50 is small, the regulator operating pressure, which is the output of the pressure reducing valve 40A, becomes high, so the switching valve 52 of the regulator 30A moves to the left, and the piston of the regulator 30A moves to the right. do. Therefore, the capacity of the motor 24A is maximized.

When the lever 50 is pushed further to the right, the regulator operating pressure of the pressure reducing valve 40A decreases so that the switching valve 52 moves to the right and the capacity of the motor 24A decreases. When the lever 50 is operated to the left side, the motor 24A is reversed so that the control system is almost the same as above and the control characteristics are almost the same as those in FIG. In FIG. 5, the same reference numerals as in FIG. 3 and the same parts are denoted by "A".

In the above embodiment, although the hydraulic pressure is used as the working fluid, the present invention also includes using a fluid such as water other than the hydraulic pressure. Moreover, although the regulator which controls the capacity of the motor 24 is the hydraulic cylinder 30 in this embodiment, and the control valve was the hydraulic pressure reducing valve 40, the control system was comprised hydraulically, but the regulator in this invention, The control valve may be one of pneumatic control and electrical control. It goes without saying that the types of the directional control valve and the control valve are not limited to this embodiment.

As described above, the present invention allows the hydraulic motor to be the maximum capacity within a predetermined operating range near the neutral position of the control lever, and the hydraulic fluid flow to the hydraulic motor is controlled by the direction switching valve. The controllability of the speed becomes good, and the speed control is performed stably.

When the pressure is generated by the load of the hydraulic motor such as the load suspended in the air, the capacity of the motor is the maximum, so the braking force is the maximum, and the drop amount of the load is minimal compared to the other so that the workability is good. do.

On the other hand, it is also possible to control the regulator and change the capacity of the motor by the operation amount of the control lever, so that the maximum speed of the original value is limited by the operation amount.

Therefore, it is a remote control characteristic that can reflect the intention of the operator, improving stability and workability.

Claims (9)

The variable displacement hydraulic motor 24 for driving the unwanted drum and the hydraulic source 20 are connected via the direction switching valve 22, and the capacity of the hydraulic motor 24 is changed according to the load by the regulator. In the hydraulic pressure source having a substantially constant horsepower output characteristic, the regulator 30 is set so that the hydraulic motor 24 has a maximum capacity within a predetermined operating range near the neutral position of the control lever 22a for controlling the direction switching valve 22. The control device of the hydraulic pressure source, characterized in that it comprises a control valve (40) for operating. 2. The control device for a hydraulic pressure source according to claim 1, wherein the amount of liquid passing through the direction switching valve (22) increases in proportion to the amount of operation within the predetermined operating range of the control lever (22a). 2. The hydraulic cylinder according to claim 1, wherein the regulator 30 is constituted by a hydraulic cylinder to which the hydraulic motor 24 is returned to the minimum capacity side, and the hydraulic chamber 34 of the hydraulic cylinder 24 is A control device connected to the liquid inlet and the liquid outlet via a high pressure selection valve (27). 2. The apparatus for controlling a hydraulic pressure source according to claim 1, wherein the control valve (40) comprises a hydraulic pressure reducing valve (40) provided between the discharge side of the hydraulic pressure source (20) and the liquid chamber of the hydraulic cylinder (30). 5. The control device of a hydraulic pressure source according to claim 4, wherein the control valve (40) detects by the cam mechanism (42) that the adjustment lever (22a) is within a predetermined operating range. 2. The control device according to claim 1, wherein the regulator (30) is formed of a pneumatic cylinder and the control valve controls the air pressure supplied to the pneumatic cylinder. The apparatus of claim 1, wherein the regulator (30) is formed of an electric servo motor so that the control valve (40) electrically detects the movement of the direction change valve (22a) to control the electric submotor. The variable displacement hydraulic motor 24A and the hydraulic source 20 for driving the unwanted drum are connected via the direction switching valve 22A, and the capacity of the hydraulic motor 24A is changed to the load by the regulator 30A. In the hydraulic pressure source having a substantially constant horsepower output characteristic, the hydraulic motor 24A being the maximum capacity within a predetermined operating range near the neutral position of the control lever 50 for controlling the direction switching valve 22A. Of the liquid inlet and the liquid outlet of the control valve 40A and the hydraulic motor 24A, which operates the regulator 30A and reduces the operating pressure of the regulator 30A according to the increase in the operation amount of the control lever 56. It is provided with a high pressure selection valve 36A which selects the hydraulic pressure on the high pressure side and sets the operating pressure of the regulator 30A, and by the operating pressure of the regulator 30A on any of the high pressure sides of the operating pressure of the regulator 30A determined by the control lever. Increase the capacity of the hydraulic motor 24A A control device, characterized in that the liquid pressure Any of controlling the regulator (30A) to the direction. 9. The control valve (40A) of claim 8, wherein the regulator (30A) is composed of a hydraulic cylinder (30A) provided with a returning habit of returning the hydraulic motor (24A) to the minimum capacity side, and the control valve (40A) of the control lever (22A). It consists of a hydraulic pressure reducing valve 40A in which the decompression amount increases according to the operation amount more than a predetermined operation amount, and this hydraulic pressure reducing valve 40A depressurizes the discharge side pressure of the hydraulic pressure source 20, and operates it as a hydraulic pressure regulator 30A. A liquid pressure source control device for supplying to the liquid chamber of (30A) while supplying the liquid inlet of the hydraulic motor (24A) and the high pressure side hydraulic pressure of the liquid outlet to the liquid chamber as a regulator (30A) operating pressure.

Images