JPH0748091A - Winch drive circuit - Google Patents

Abstract

PURPOSE:To appropriately control a winch motor at its combined operation by increasing discharge capacity of the winch motor, before the total loading pressure of a hydraulic actuator and the winch motor reaches its maximum- capacity pressure. CONSTITUTION:When hydraulic motors 3, 32 are placed in their complex operation, the discharge pressure of a hydraulic pump 1 is equal to the total pressure of consumption pressure of the hydraulic motor 32 and loading pressure of the hydraulic motor 3. When the total pressure is increased and an upper limit side pressure switch 40 reaches a set pressure, ON signal is output and signal S3 is output from a latching relay 42 to a relay 43 so as to excite 2 relay coil RS2. Power supply of the solenoid of a switching valve 12 is cut out thereby so as to be fixed at A position. Then, pilot pressure flowing from a switching valve 11 to a switching valve 15 is cut off by the switching valve 12 and the switching valve 15 is fixed at B position, so that pressure of the oil pressure 18a of a regulator 18 is released to a tank 9. Therefore discharge capacity of the hydraulic motor 3 is fixed at the maximum, even if the loading pressure is under the set pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit for driving a winch by a variable displacement hydraulic motor.

[0002]

2. Description of the Related Art As a winch drive circuit having a variable displacement hydraulic motor, for example, JP-A-3-57033, JP-A-5-17961 and JP-A-3-1025 are available.
The ones described in JP-A-91 and JP-A-60-191993 are known.

FIG. 3 shows an example of a winch drive circuit of this type. In the figure, 1 is a variable displacement hydraulic pump as a hydraulic source for driving a winch, 2 is a hydraulic pump for driving various control valves, etc. These hydraulic pumps 1 and 2 are prime movers (not shown) (for example, diesel engine).
Driven by. 3 is a variable displacement hydraulic motor for driving a winch, 4 is a control valve for controlling the flow of pressure oil from the hydraulic pump 1 to the hydraulic motor 3, and 5 is a pilot valve for switching and controlling the control valve 4. When the operation lever 5a of the pilot valve 5 is tilted from the upright position shown to either side in the direction of the arrow in the drawing, the pressure depending on the operation amount of the operation lever 5a from the valve 5b or 5c on the tilted side becomes the pilot conduit 6a or It is output to 6b. Accordingly, the control valve 4 is switched to the A position side or the B position side, the pressure oil from the hydraulic pump 1 is guided to the hydraulic motor 3, and the rotation thereof is transmitted to the winch drum 8 via the speed reducer 7. When the operation lever 5a of the pilot valve 5 is in the upright position, the control valve 4 is held in the neutral position, and the entire amount of pressure oil from the hydraulic pump 1 is returned to the tank 9. When the control valve 4 is switched to the A position side, the drum 8 rotates in the hoisting direction of the suspended load.

When the operating lever 5a is operated and the pressure rises in the pilot pipe lines 6a and 6b, the pressure acts on the pilot port of the switching valve 11 via the high pressure selection valve 10, and the switching valve 11 is moved from the A position. The discharge pressure PS of the hydraulic pump 2 is guided to the switching valve 12 by switching to the B position. At this time, if the switch 13 is turned on and the switching valve 12 is switched to the B position, the pressure PS is reduced by a predetermined amount by the pressure reducing valve 14 and then acts on the pilot port on the A position side of the switching valve 15. The outlet pressure at the time of winding of the hydraulic motor 1 also acts on the pilot port on the A position side of the switching valve 15 via the conduit 16. On the other hand, either the discharge pressure PS of the hydraulic pump 2 or the inlet pressure of the hydraulic motor 3 whichever is higher acts on the pilot port on the B position side of the switching valve 15 via the high pressure selection valve 17.

The pressure receiving area of the pilot port of the switching valve 15 is adjusted so that the switching valve 15 is fixed at the position A in the range where the difference between the inlet pressure and the outlet pressure of the hydraulic motor 3 is smaller than a predetermined value. When the switching valve 15 is in the A position, the output pressure of the high pressure selection valve 17 is the oil chamber 1 of the pump regulator 18.
8a, the pressure of the oil chamber 18b on the opposite side is released to the tank 9 via the conduit 19. Thus, when the load on the winch is small, the discharge capacity of the hydraulic motor 3 is set to the minimum value, the drum 8 is rotationally driven at high speed, and the work efficiency is increased. On the other hand, when the load on the winch increases and the difference between the inlet pressure and the outlet pressure of the hydraulic motor 3 at the time of winding increases, the switching valve 15 switches from the A position to the B position side. As a result, the inlet pressure of the hydraulic motor 3 changes to the regulator cylinder 1
8 to the oil chamber 18b side, the discharge capacity of the hydraulic motor 3 increases, and the inlet pressure is maintained within the range of the maximum allowable pressure by the relief valve 20, and the hoisting torque commensurate with the load is secured. The difference between the inlet pressure and the outlet pressure of the hydraulic motor 3 is the so-called load pressure of the hydraulic motor 3, and in the circuit shown in the figure, the outlet pressure is the tank pressure, so the load pressure substantially matches the inlet pressure.

4 and 5 show the relationship between the load pressure of the hydraulic motor 3 and the discharge capacity or output torque in the circuit of FIG. As is clear from these figures, the load pressure is P
Until reaching 1, the discharge volume is kept at the minimum value q _min ,
The output torque increases in proportion to the increase in load pressure. While the load pressure exceeds P1 and reaches P2, the discharge capacity increases in proportion to the increase of the load pressure, and the output torque rapidly increases in combination with the increase of the load pressure and the discharge capacity. Then, the maximum discharge capacity q _max is reached at the load pressure P2, and thereafter, the output torque gradually increases up to the relief pressure in proportion to only the load pressure. When the switch 13 is turned off in the circuit of FIG. 3, the pilot pressure from the switching valve 11 to the switching valve 15 is blocked by the switching valve 12, the switching valve 15 is fixed at the B position, and the discharge capacity of the hydraulic motor 3 is increased. Is fixed to the maximum value regardless of winch load.

[0007]

Since the conventional winch drive circuit is constructed on the premise of a so-called 1-pump-1 motor type circuit in which an independent hydraulic pump 1 drives an independent hydraulic motor 3, a plurality of plural winch drive circuits are provided. When a so-called series circuit in which a hydraulic motor is connected in series to a common hydraulic power source is configured, it is inconvenient to adopt it as it is. One example is
The series circuit shown in FIG. 6 constructed based on the circuit shown in FIG. 3 will be described.

In the circuit of FIG. 6, the hydraulic pump 1 and the control valve 4 are
The control valve 30 is interposed between the control valve 30 and the control valve 30. When the control valve 30 is in the neutral position, the discharge pressure of the hydraulic pump 1 is guided to the control valve 4 as it is. When the control valve 30 is switched to the A position or the B position side according to the operation of the pilot valve 31, the discharge oil of the hydraulic pump 1 is supplied to the hydraulic motor 32, and the boom raising / lowering drum 34 is moved via the reduction gear 33. It is driven to rotate. Then, the return oil from the hydraulic motor 32 is guided to the control valve 4 side via the control valve 30. When the hydraulic motor 32 is driven, the pressure introduced to the control valve 4 becomes lower than the discharge pressure of the hydraulic pump 1 by the consumed pressure on the hydraulic motor 32 side.
Therefore, for example, the set pressure of the relief valve 20 is 30M.
If Pa and the consumption pressure in the hydraulic motor 32 are 15 MPa, the inlet pressure of the hydraulic motor 3 can only be increased to 15 MPa at the maximum. In this case, when the set value of the load pressure of the hydraulic motor 3 (pressure P1 in FIG. 4) at the time when the switching valve 15 starts the switching operation from the A position to the B position is larger than 15 MPa, the combined hydraulic motors 3 and 32 are combined. During operation, the hydraulic motor 3 is always driven with the minimum discharge capacity. Therefore, the increase rate of the load pressure of the hydraulic motor 3 with respect to the increase of the load of the winch is large, and the relief valve 20 is activated, and the hydraulic motors 3 and 32 are likely to stop.

Here, in order to reduce the load pressure of the hydraulic motor 3 during the combined operation, the setting of the pressure P1 in FIG. 4 may be changed to the low pressure side to accelerate the timing at which the discharge capacity of the hydraulic motor 3 increases. . However, in this case, even when the hydraulic motor 3 side is operated independently, the timing of the increase of the discharge capacity with respect to the increase of the load of the winch becomes earlier, and the drum 8
Rotation speed is relatively reduced, and workability is reduced. Figure 6
It is conceivable that the switch 13 is turned off only when the combined operation is performed in the above circuit.
The operation to switch 3 is extremely troublesome.

An object of the present invention is to provide a winch drive hydraulic motor for combined operation without deteriorating workability in independent operation of the winch side even when the winch drive hydraulic motor is connected in series with another hydraulic actuator. It is to provide a winch drive circuit capable of appropriately controlling the discharge capacity of the.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1 showing an embodiment, the present invention will be described. In the present invention, a variable displacement winch drive hydraulic motor 3 driven by pressure oil from a hydraulic power source 1 is used.
And a discharge capacity control means 15 for increasing the discharge capacity when the load pressure of the winch driving hydraulic motor 3 exceeds a predetermined set value, and a hydraulic actuator 32 driven by the pressure oil from the hydraulic source 1. The pressure oil from the hydraulic power source 1 is applied to a winch drive circuit that is guided to the winch drive hydraulic motor 3 side via a hydraulic actuator 32.
Then, when the total pressure of the consumption pressure of the hydraulic actuator 32 and the load pressure of the winch drive hydraulic motor 3 approaches the maximum allowable pressure of the circuit to a certain range, the load pressure of the winch drive hydraulic motor 3 becomes Capacity switching point changing means 12 for increasing the discharge capacity of the winch drive hydraulic motor 3 even if it is less than or equal to the set value of the discharge capacity control means 15,
By providing 40 to 43, the above-mentioned object is achieved. In the circuit according to claim 2, the capacity switching point changing means 12, 40 is associated with an increase in the total pressure of the hydraulic actuator 32 and the load pressure of the winch driving hydraulic motor 3.
˜43, the displacement switching point changing means 12, 40-43 increase the discharge capacity with the value of the total pressure when the discharge capacity of the winch drive hydraulic motor 3 starts increasing. It was set to be larger than the value of the total pressure at the time of stopping.

[0012]

In the combined operation of the winch driving hydraulic motor 3 and the other hydraulic actuator 32, the discharge capacity control means 1
Regardless of the set value of 5, the discharge capacity of the winch drive hydraulic motor 3 increases before the total pressure of the hydraulic actuator 32 and the load pressure of the winch drive hydraulic motor 3 reaches the maximum allowable pressure of the circuit. To do. When the winch drive hydraulic motor 3 is operated independently, the discharge capacity control means 15 can change the discharge capacity of the winch drive hydraulic motor 3 according to a diagram suitable for the operation of the winch alone.

According to the second aspect of the present invention, even if the load pressure of the winch drive hydraulic motor 3 is decreased in response to an increase in the discharge capacity of the winch drive hydraulic motor 3 by the capacity switching point changing means 12, 40 to 43,
Immediately, the discharge capacity does not decrease, and the frequency of switching the discharge capacity decreases.

Incidentally, in the section of means and action for solving the above-mentioned problems for explaining the constitution of the present invention, the drawings of the embodiments are used for the sake of easy understanding of the present invention. It is not limited to.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS. The same parts as those of the circuits of FIGS. 3 and 6 described above are designated by the same reference numerals, and the description thereof will be omitted. Figure 1
In this embodiment, as shown in FIG.
An upper limit side pressure switch 40 and a lower limit side pressure switch 41 that are turned on / off according to the discharge pressure of the hydraulic pump 1 are added. As shown in FIG. 2 (a), the upper limit side pressure switch 40 controls the discharge pressure of the hydraulic pump 1 to be the relief valve 20 (FIG.
The off signal is output until the set pressure Ps2, which is slightly lower than the set pressure of (see), is reached, and the on signal is output when the set pressure Ps2 is exceeded. Further, the lower limit side pressure switch 41 has a set pressure Ps1 in which the discharge pressure of the hydraulic pump 1 is lower than the set pressure Ps2 of the upper limit side pressure switch 40 as shown in FIG. 2B.
The ON signal is output until the pressure reaches P, and the OFF signal is output when the set pressure Ps1 is exceeded. The set pressure Ps2 is set higher than the pressure P2 in FIG.

As shown in FIG. 1, the upper limit pressure switch 4
The output signal of 0 is the set side terminal 42a of the latch relay 42.
And the output signal of the lower limit side pressure switch 41 is input to the reset side terminal 42b of the latch relay 42. When the ON signal is input to the set side terminal 42a, the internal contact 4
2s is closed, signal S2 is output, and reset side terminal 4
When the ON signal is input to 2b, the internal contact 42s is opened and the output of the signal S2 is blocked. When the ON signal is not input to either the set side terminal 42a or the reset side terminal 42b, the internal contact 42s is held in the previous state. Therefore, the discharge pressure of the hydraulic pump 1 is set to the upper limit side pressure switch 4
If a cycle is considered in which the pressure exceeds the set pressure Ps2 of 0 and rises to the vicinity of the set pressure of the relief valve 20 and then decreases to the set pressure Ps1 of the lower limit side pressure switch 41 or less, FIG.
As indicated by the arrow in (c), the signal S2 is not output in the sections 1 and 2, and the signal S2 is continuously output in the sections 2 to 6.

The output signal S2 from the latch relay 42 is input to the relay coil R2 of the relay 43. Relay 43
Is a relay contact 43a closed by excitation of the relay coil R1 and a relay contact 43b closed by release of excitation of the relay coil R2, which are connected in series between the power source E and the solenoid of the switching valve 12. The relay coil R1 is connected to the switch 13 described above.

When the switch 13 is turned on in the above circuit, the relay contact 43a is closed by the excitation of the relay coil R1 of the relay 43, and the relay coil R2 is in the non-excited state unless the signal S2 is output from the latch relay 42. And the relay contact 43b is also closed. In this state, the solenoid of the switching valve 12 is excited and the switching valve 12
Switches to the B position, and the hydraulic pump 2 switches the switching valves 11, 1
A predetermined pilot pressure is introduced to the pilot port on the A position side of the switching valve 15 via the pressure reducing valve 2 and the pressure reducing valve 14. At this time, the discharge capacity of the hydraulic motor 3 tends to change according to the above-mentioned diagram of FIG.

When the hydraulic motor 32 for raising and lowering the boom is driven by operating the operating lever 31, the pressure guided to the hydraulic motor 3 is higher than the discharge pressure of the hydraulic pump 1 by the pressure consumed by the hydraulic motor 32. Get lower. In other words, the discharge pressure of the hydraulic pump 1 when the hydraulic motors 3 and 32 are operated in combination is equal to the total pressure of the hydraulic motor 32 and the load pressure of the hydraulic motor 3. When this total pressure rises and reaches the set pressure Ps2 of the upper limit side pressure switch 40,
An ON signal is output from the upper limit side pressure switch 40, a signal S2 is output from the latch relay 42 to the relay 43, and the relay coil R2 is excited. As a result, the power of the solenoid of the switching valve 12 is cut off, and the switching valve 12 is fixed at the A position. Then, the pilot pressure from the switching valve 11 to the switching valve 15 is blocked by the switching valve 12, the switching valve 15 is fixed at the B position, and the pressure of the oil chamber 18a of the regulator 18 is released to the tank 9. Therefore, the discharge capacity of the hydraulic motor 3 is fixed to the maximum value even if the load pressure is equal to or lower than the set pressures P1 and P2 shown in FIG.

Once the upper limit side pressure switch 40 is turned on, unless the discharge pressure of the hydraulic pump 1 falls below the set pressure Ps1 of the lower limit side pressure switch 41 as shown in FIG. Continues to be output,
The discharge capacity of the hydraulic motor 3 remains fixed at the maximum value. When the discharge pressure of the hydraulic pump 1 drops below the set pressure Ps1, the output of the signal S2 from the latch relay 42 to the relay 43 disappears and the relay contact 43b closes.
As a result, the switching valve 12 is switched to the B position and the discharge capacity of the hydraulic motor 3 is controlled as shown in the diagram of FIG.

Since the relay contact 43a is opened when the switch 13 is turned off, the switching valve 12 is fixed at the A position and the discharge capacity of the hydraulic motor 3 reaches the maximum value regardless of whether the pressure switches 40 and 41 are on or off. Fixed to.

As is clear from the above, in this embodiment, when the switch 13 is turned on to control the discharge capacity of the hydraulic motor 3 in accordance with the load of the winch, the hydraulic motor 32 is driven and the hydraulic pressure is changed by the consumed pressure. Even when the load pressure of the motor 3 is limited to be lower than the pressure P1 set as the switching point of the discharge capacity by the switching valve 15, when the discharge pressure of the hydraulic pump 1 reaches the set pressure Ps2 of the upper limit side pressure switch 40, the hydraulic motor 3 The discharge capacity of is switched to the maximum value. Therefore, while ensuring the output torque of the hydraulic motor 3 according to the load of the winch, the discharge pressure of the hydraulic pump 1 is adjusted to the relief valve 2
It is possible to prevent the hydraulic motors 3 and 32 from stopping by maintaining the set pressure at 0 or less. When the hydraulic motor 32 is not driven, the discharge pressure of the hydraulic pump 1 is the set pressure P of the upper limit pressure switch 40.
The load pressure of the hydraulic motor 3 is shown in FIG. 4 before reaching s2.
Since the set values Ps1 and Ps2 of the hydraulic motor 3 are reached, the discharge capacity of the hydraulic motor 3 changes as shown in the diagram of FIG. Therefore, the workability of the winch during the independent operation does not deteriorate.

In this embodiment, in particular, the pair of pressure switches 4
Since the set pressure Ps2 when the discharge capacity of the hydraulic motor 3 starts to increase by setting 0, 41 is made larger than the set pressure Ps1 when the increase of the discharge capacity is stopped, the hydraulic motor 3 increases due to the increase of the discharge capacity. Since the switching valve 12 does not immediately return to the original B position side even if the load pressure of is decreased, the switching frequency of the discharge capacity of the hydraulic motor 3 during the combined operation is reduced and the change in the rotation speed of the winch drum 8 is smooth. become. If the set pressures Ps1 and Ps2 are equal, the discharge capacity immediately decreases due to the decrease in the load pressure due to the increase in the discharge capacity, and the rotation speed of the drum 8 increases and decreases frequently.

In the circuit of this embodiment, only the pressure switches 40 and 41 are connected to the circuit of FIG. 6 and the relays 42 and 43 for processing the detection signals of these pressure switches are added. Therefore, the existing hydraulic circuits are not changed. Can be easily connected to the circuit.

In the correspondence between the above embodiment and the claims,
The hydraulic pump 1 serves as a hydraulic source, the hydraulic motor 3 serves as a winch driving hydraulic motor, the switching valve 15 serves as a discharge capacity control means, the hydraulic motor 32 serves as a hydraulic actuator, the switching valve 12, the pressure switches 40 and 41, and the latch relay 42. The relay 43 constitutes a capacity switching point changing means, and the set pressure of the relief valve 20 corresponds to the maximum allowable pressure of the circuit. In the embodiment, the set pressure P1 and the set pressure P2 in FIG. 4 may be equal. The hydraulic power source may be composed of a plurality of hydraulic pumps. Even when the pressure reducing valve 14 is changed to a variable type and the pressure reducing degree of the pressure reducing valve 14 is increased when the pressure switch 40 is turned on, the switching valve 15 is fixed to the B position side, and the same effect as the embodiment is obtained. To be In the embodiment, the switching valve 12 is switched and controlled by the combination of the latch relay 42 and the relay 43. However, the pressure sensor that detects the discharge pressure of the hydraulic pump 1 and the software that controls the switching valve 12 according to the detection result. It is also possible to provide a microcomputer provided with and perform switching control in the same manner.

[0026]

As described above, according to the present invention,
During combined operation of the winch drive hydraulic motor and other hydraulic actuators, the total pressure of the hydraulic actuator consumption pressure and the winch drive hydraulic motor load pressure is the maximum allowable pressure of the circuit regardless of the set value of the discharge capacity control means. Since the discharge capacity of the winch drive hydraulic motor increases before reaching, the work capacity when operating the winch drive hydraulic motor alone is not reduced, and the discharge capacity of the winch drive hydraulic motor is appropriately adjusted during combined operation. Can be controlled. According to the circuit of the second aspect, the discharge capacity of the winch driving hydraulic motor is switched less frequently during the combined operation, and the change in the rotation speed of the winch due to the increase or decrease of the discharge capacity becomes smooth.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an embodiment of the present invention.

2 is a discharge pressure and pressure switch 4 of the hydraulic pump 1 of FIG.
The figure which shows the relationship with the output signal of 0,41.

FIG. 3 is a diagram showing an example of a circuit for changing a discharge capacity of a winch driving hydraulic motor 3 according to a load of a winch.

4 is a diagram showing a relationship between a load pressure of a winch driving hydraulic motor 3 and its discharge capacity in the circuit of FIG.

5 is a diagram showing the relationship between the load pressure of the winch drive hydraulic motor 3 and its output torque in the circuit of FIG.

6 is a diagram showing an example in which another hydraulic motor 32 is connected in series between the hydraulic pump 1 and the winch driving hydraulic motor 3 of FIG. 3 to form a series circuit.

[Explanation of symbols]

 1 Hydraulic pump 3 Hydraulic motor for winch drive 12 Switching valve 15 Switching valve 20 Relief valve that sets the maximum allowable pressure of the circuit 32 Hydraulic motor for boom / elevation 40 Upper pressure switch 41 Lower pressure switch 42 Latch relay 43 Relay

Claims (2)

[Claims] 1. A variable displacement winch drive hydraulic motor driven by pressure oil from a hydraulic source, and a discharge for increasing its discharge capacity when the load pressure of the winch drive hydraulic motor exceeds a predetermined set value. A winch drive circuit including a capacity control means and a hydraulic actuator driven by pressure oil from the hydraulic source, and the pressure oil from the hydraulic source is guided to the winch driving hydraulic motor side via the hydraulic actuator. In, when the total pressure of the consumption pressure in the hydraulic actuator and the load pressure of the winch drive hydraulic motor approaches a certain range with respect to the maximum allowable pressure of the circuit, the load pressure of the winch drive hydraulic motor is A capacity switching point changing means for increasing the discharge capacity of the winch drive hydraulic motor even if the discharge capacity control means is less than or equal to the set value. Winch drive circuit, characterized in that digit. 2. The winch drive circuit according to claim 1, wherein the displacement switching point changing means starts increasing the discharge capacity of the winch drive hydraulic motor as the total pressure rises. The winch drive circuit is characterized in that a set value is set to be larger than a set value of the total pressure when the capacity switching point changing means stops increasing the discharge capacity due to the decrease in the total pressure. .