JPS6283996A - Low horse-power type hydraulic winch controller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a constant horsepower hydraulic winch control device for use in cargo handling winches and other hydraulic lifting machines.

[Conventional technology]

As prior art to the present invention, there is a constant horsepower control valve winch control device described in Japanese Patent Application Laid-Open No. 58-89589. This conventional device will be explained with reference to FIG. 4. A directional control valve 3 connected to a hydraulic pressure source 1 and a tank 2 is connected to a variable displacement motor 4 through a flow path 6 and a flow path 7 through which a counterbalance valve 5 is interposed. is,
A flow path 9 and a flow path 7 connecting the check valve 8 of the counterbalance valve 5 and the variable displacement motor 4 are connected via a shuttle valve 12 to a hydraulic switching valve 36 of 5 points and 3 positions and a constant horsepower control valve 1.
6 P ports, respectively.

The hydraulic switching valve 36 guides the hydraulic pressure in the flow path 17 connecting the check valve 8 and the directional switching valve 3 and the hydraulic pressure in the flow path 7 to the end of the spool 37 as pilot pressure, and controls the cylinder 20 of the neutral constant horsepower control valve 16. The fluid chamber 21 of the constant horsepower control valve 16 is connected to the tank 2 via the sequence valve 38, and the fluid chamber 19 of the constant horsepower control valve 16 is connected to the secondary port of the shuttle valve 12, so that the motor supply pressure is connected to the fluid chamber at the load hoisting position ia. Lead to 19, 21,
When the load is lower than the rated load, the motor braking pressure is guided to the liquid chamber 21 through the sequence valve 38, and the liquid chamber 19 is communicated with the tank 2.

The constant horsepower control valve 16 controls the displacement control cylinder 24 of the variable displacement motor 4, and its set pressure is set to the cylinder 20.
It is set by compressing the inner spring 29 by a predetermined length by the piston 28 which receives hydraulic pressure.

Now, when the directional control valve 3 is set at position a, the hydraulic fluid from the hydraulic pressure source 1 flows into the variable displacement motor 4 via the directional control valve 3 and the check valve 8, and the discharged liquid flows through the flow path 7 and the directional control valve 8. It flows into the tank 2 via the valve 3, and the variable displacement motor 4 rotates in the load hoisting direction. At that time, the hydraulic switching valve 36 is connected to flow paths 6 and 17.
Position a is taken due to the pressure difference between the motor supply pressure and the motor supply pressure to the liquid chambers 19 and 21 of the constant horsepower control valve 16. As a result, when the motor supply pressure is lower than the set pressure of the constant horsepower control valve 16, the spool 27 takes position a and the small capacity switching chamber 26
Since the motor supply pressure is guided to communicate the large capacity switching chamber 25 with the tank 2, the variable displacement motor 4 has a minimum displacement per revolution and can hoist the load at high speed. When the motor supply pressure and the set pressure of the constant horsepower control valve 16 are equal, the spool 27 takes a neutral position and blocks the large-capacity switching chamber 25 and the small-capacity switching chamber 26, so that the displacement volume and hoisting speed remain constant. . When the load is between W1 and W2 shown in Fig. 5, when the motor supply pressure decreases below the set pressure of the valve 16, the spool 27 will move to 7jla, and the displacement per revolution of the remote will decrease and the hoisting speed will decrease. When the motor supply pressure increases and becomes equal to the set pressure of the valve 16, the spool 27 takes a neutral position and the displacement becomes constant. Conversely, when the motor supply pressure increases from this neutral state, the spool 27 takes its position and moves into the large capacity switching chamber 25.
Since the motor supply pressure is guided to communicate the small capacity switching chamber 26 with the tank 2, the displacement volume increases and the motor hoisting speed decreases. 25 takes a neutral position. In this way, when the load is between W1 and W2, winch control is performed where the hoisting speed x load is constant, that is, the horse power is constant.

Next, when the directional control valve 3 is switched from the neutral position to the neutral position, the hydraulic fluid from the hydraulic pressure source 1 flows into the variable displacement motor 4 via the directional control valve 3 and the flow path 7, and the discharged fluid flows into the counterbalanced motor 4. The fluid flows to the tank 2 via the valve 5 and the directional switching valve 3, and the variable displacement motor 4 rotates in the direction of lowering the load, generating motor braking pressure in the flow path 9. On the other hand, the hydraulic switching valve 36 is connected to the flow paths 7 and 17.
Due to the pressure difference between has the minimum displacement and lowers the load at high speed.

When the motor braking pressure exceeds the set pressure of the sequence valve 38 during load lowering, the sequence valve 38 switches from position a to position a and communicates the liquid chamber 21 with the tank 2.
expands and the spring force decreases, which causes the spool 27 to take its position, so that the variable displacement motor 4 has a maximum displacement and lowers the load at a low speed.

By the way, in the conventional device as described above, the hydraulic pressure in the flow path 7 is released to the flow path 17 via the safety valve 39 in order to prevent the sequence valve 38 from malfunctioning.

That is, when the directional control valve 3 is placed in the neutral position and the rated load is suspended, motor braking pressure is generated in the flow path 9. When the directional control valve 3 is positioned to lower the load in this state, surge pressure for starting the variable displacement motor 4 builds up in the flow path 7, and in response to this, the braking pressure in the flow path 9 increases. Boost the pressure.

When this pressure exceeds the set pressure of the sequence valve 38, the sequence valve 38 switches to the position to communicate the liquid chamber 21 with the tank 2, and the spool 27 assumes the position, so that the displacement of the variable displacement motor 4 increases. becomes maximum, and a load that should be lowered at high speed may be lowered at low speed. Therefore, the surge pressure in the flow path 7 is regulated by the safety valve 39 so that the pressure in the flow path 9 does not exceed the set pressure of the sequence valve 38 when lowering a load below the rated load W2.

[Problem that the invention attempts to solve]

However, when the safety valve operates, a portion of the pump discharged liquid escapes to the tank and the amount of liquid supplied to the motor decreases, resulting in a lowering speed and lowering the cargo handling efficiency. Additionally, problems of heat generation and noise occur due to the operation of the safety valve.

This idea was made in view of the above points, and it solves the above problems with a simple configuration that eliminates the need for the safety valve, and also reduces the motor 1 depending on the size of the load when lowering an excessive load. The purpose of the present invention is to provide a safe constant horsepower type wave pressure winch control device that controls the displacement per rotation and prevents an abnormal increase in motor braking pressure.

[Means for solving problems]

The structure of the present invention for achieving the above object will be explained using FIGS. 1 to 3.

A hydraulic pressure: 6JX1 is connected to a variable displacement motor 4 equipped with a counterbalance valve 5 via a directional control valve 3, and a constant horsepower control valve 16 is connected to the constant horsepower control valve 16 as pilot pressure when hoisting a load. A hydraulic pressure switching valve 14 is provided to guide the motor supply pressure and the motor braking pressure during load lowering via the constant pressure reducing valve 23, and the constant horsepower control valve 1G is variable when its set pressure exceeds the pilot pressure. Capacitive motor 1
The displacement control cylinder 24 of the variable displacement motor 4 is controlled so that the displacement per rotation is increased, conversely when it is low, it is decreased, and when the displacement is balanced, the displacement becomes constant.

[For production]

In the neutral state shown in FIGS. 1 and 2, when the directional control valve 3 is switched from the neutral position to the position, the hydraulic fluid from the hydraulic pressure source 1 passes through the directional control valve 3 and the flow path 7 to the variable displacement motor 4, the discharged liquid flows to the tank 2 via the counterbalance valve 5 and the directional switching valve 3, the variable displacement motor 4 rotates in the direction of lowering the load, and motor braking pressure is generated in the flow path 9. On the other hand, the hydraulic pressure switching valve 14 guides the motor braking pressure to the liquid chamber 21 of the constant horsepower control valve 16 and sets the valve 16 to a predetermined pressure. Lead to 19. In this case, the pressure reduction ratio of the constant pressure reducing valve 23 is determined so that the motor braking pressure generated when lowering the rated load W2 is reduced to a pressure equal to the set pressure of the constant horsepower control valve 16, so that the load is lower than the rated load. When the load is lighter than W2, the constant horsepower control valve 16 takes position a, and the variable displacement motor 4 has a minimum displacement per rotation, lowering the load at high speed. When the load is above the rated load W2, the constant horsepower control valve 16 assumes the position when the hydraulic pressure acting on the liquid chamber 19 exceeds the set pressure. As a result, the displacement per revolution of the variable displacement motor 4 increases and the lowering speed decreases.As a result, the motor braking pressure decreases and when the fluid pressure in the fluid chamber 19 becomes equal to the set pressure, constant horsepower control is performed. The valve 16 takes a neutral position and the displacement becomes constant. Conversely, when the liquid pressure in the liquid chamber 19 falls below the set pressure, the constant horsepower control valve 16 assumes position a, so the displacement volume decreases and the lowering speed increases, and the motor braking pressure increases accordingly. When the hydraulic pressure 19 becomes equal to the set pressure, the constant horsepower control valve 16 assumes a neutral position, so that the displacement becomes constant. That is, as shown in FIG. 3, when the load is lighter than the rated load W2, the maximum lowering speed is achieved, and when the load is greater than the rated load W2, constant horsepower control is performed, so that no abnormal increase in motor braking pressure occurs.

〔Example〕

Embodiments of the present invention will be described based on the drawings. In FIG. 1, a directional control valve 3 connected to a hydraulic pressure source 1 and a tank 2 is connected to a variable displacement motor 4 through a flow path 6 and a flow path 7 in which a counterbalance valve 5 is interposed. The flow path 9 and the flow path 7 connecting the check valve 8 and the variable displacement motor 4 are connected to the shuttle valve 12 by the passage 10 and the passage 11.
The secondary boat of the shuttle valve 12 is connected to the passageway 3.
The 6-bottle, 3-position hydraulic pressure switching valve 14 is connected to the passage 1.
3.15 are respectively connected to the P port of the constant horsepower control valve 16.

The hydraulic pressure switching valve 14 counteracts the hydraulic pressure in a flow path 17 connecting the check valve 8 and the directional control valve 3 with the hydraulic pressure in the flow path 7 via a spool 18, and controls the hydraulic pressure in the neutral constant horsepower control valve 16. room 19
is connected to the secondary boat of the shuttle valve I2, the liquid chamber 21 of the cylinder 20 is connected to the tank 2 via the return passage 22, and the pilot piston 31 of the liquid chamber 19 of the constant horsepower control valve 16 is connected to the position a when the load is hoisted. The motor supply pressure is guided to the piston 28 of the liquid chamber 21, and the motor braking pressure in the flow path 9 is guided to the liquid chamber 21 at the time of lowering the load. I'm leading you to room 19. The pressure reduction ratio of the electric ratio pressure reducing valve 23 is such that the motor braking pressure generated upstream of the check valve 8 at the time of lowering the rated load W2 is equal to the constant horsepower control valve 1.
It is determined that the pressure is to be reduced until the pressure becomes equal to the set pressure of No. 6.

The constant horsepower control valve 16 connects a passage 15 communicating with the secondary boat of the shuttle valve 12 and a return passage 22 communicating with the tank 2 to a displacement control cylinder 240 for controlling the displacement per revolution of the variable displacement motor 4. It is selectively connected to the chamber 25 and the small capacity switching chamber 26, and the displacement per rotation of the motor increases when the pressure liquid is introduced to the large capacity switching chamber 25, and when the pressure liquid is introduced to the small capacity switching chamber 26. It decreases when it is drained.

Note that the set pressure of the constant horsepower control valve 16 is the same as in the conventional device, when the piston 28 is controlled by the motor supply pressure or motor braking pressure guided to the liquid chamber 21 of the cylinder 20 at the intermediate stage 33 of the cylinder 20.
The spring 20 is set by compressing the spring 20 to a predetermined length.

Next, the operation of this embodiment will be explained. When the directional control valve 3 is placed in position a in the neutral state shown in FIG. The liquid flows into the tank 2 via the flow path 7 and the directional switching valve 3, and the variable displacement motor 4 rotates in the load hoisting direction. At this time, the spool 18 of the hydraulic pressure switching valve 14 assumes position a due to the motor supply pressure in the flow path 17, and guides the motor supply pressure to the liquid chambers 19 and 21 of the constant horsepower control valve 16. As a result, the hoisting load for the set pressure of the constant horsepower control valve 16 is the load W shown in FIG. Since the motor supply pressure is guided to connect the large capacity switching chamber 25 to the tank 2, the variable displacement motor 4 has a minimum displacement per revolution and can hoist the load at high speed.

If the hoisting load is between W1 and W2 shown in Figure 3,
When the motor supply pressure is equal to the set pressure of the constant horsepower control valve 16, the spool 27 takes a neutral position and blocks the large capacity switching chamber 25 and the small capacity switching chamber 26, so the displacement of the variable displacement motor 4 is constant. Hoist the load at a constant speed. When the motor supply pressure falls below the set pressure of the constant horsepower control valve 16, the spool 27 assumes position a and directs the motor supply pressure to the small capacity switching chamber 26 and communicates the large capacity switching chamber 25 with the tank 2. When the displacement of the variable displacement motor 4 decreases and the hoisting speed increases, and the motor supply pressure that increases accordingly becomes equal to the set pressure of the constant horsepower control valve 16, the spool 27 assumes the neutral position and the variable displacement motor 4 The displacement of is constant.

Conversely, when the motor supply pressure becomes higher than the set pressure, the spool 27 takes its position and directs the motor supply pressure to the large capacity switching chamber 25 and communicates the small capacity switching chamber 26 with the tank 2, so that the displacement volume increases. When the hoisting speed decreases and the motor supply pressure that decreases accordingly becomes equal to the set pressure of the constant horsepower control valve 16, the spool 27 assumes a neutral position, so the displacement of the variable displacement motor 4 becomes constant and the load is reduced. Wind up at a constant speed. In this way, when the load is between W1 and W2, winch hoisting control is performed where the hoisting speed x load is constant, that is, the horse power is constant.

Next, when the directional control valve 3 is switched from the neutral position to the neutral position, the hydraulic fluid from the hydraulic pressure source 1 flows into the variable displacement motor 4 via the directional control valve 3 and the flow path 7, and the discharged fluid flows into the counterbalanced motor 4. The fluid flows to the tank 2 via the valve 5 and the directional switching valve 3, and the variable displacement motor 4 rotates in the direction of lowering the load, generating motor braking pressure in the flow path 9. On the other hand, the hydraulic pressure switching valve 14 takes a position depending on the motor supply pressure in the flow path 7, and changes the motor braking pressure in the flow path 9 selected by the shuttle valve 12 to the constant horsepower control valve 16.
At the same time, the motor braking pressure is introduced into the electric ratio pressure reducing valve 2.
3 to the liquid chamber 19. In this case, electric ratio pressure reducing valve-2
The pressure reduction ratio of 3 is determined so that the motor braking pressure generated when lowering the rated load W2 is reduced to a pressure equal to the set pressure of the constant horsepower control valve 16. Therefore, when the load is lighter than the rated load W2, the spool 2 of the constant horsepower control valve 16
7 takes position 3a, and the variable displacement motor 4 has a minimum displacement and lowers the load at a high speed. When the load is above the rated load W2, the spool 27 of the constant horsepower control valve 16 assumes a neutral position when the pressure introduced into the liquid chamber 19 is equal to the set pressure, and assumes the neutral position when the pressure exceeds the set pressure. When the spool 27 reaches its position, the displacement per revolution of the motor increases and the unwinding speed decreases, and accordingly, the motor braking pressure decreases and when the fluid pressure in the fluid chamber 19 becomes equal to the set pressure, The spool 27 assumes a neutral position. Conversely, when the liquid pressure in the liquid chamber 19 falls below the set pressure, the spool 27 assumes position a, which reduces the displacement per rotation of the motor and increases the lowering speed. Correspondingly, the motor braking pressure increases and when the liquid pressure in the liquid chamber 19 becomes equal to the set pressure, the spool 27 assumes a neutral position, so that the displacement per motor rotation becomes constant, resulting in constant speed lowering.

The relationship between the lowering speed and load when lowering a load is shown in Figure 3. If the load is less than the rated load W2, the load is lowered at the maximum speed, and when the load is higher than the rated load, constant horsepower control is applied. The lowering speed corresponds to the size of the load. Therefore, the motor braking pressure does not rise abnormally, and efficient lowering can be achieved.

In the embodiment shown in FIG. 2, when lowering a load, the hydraulic pressure switching valve 14
This embodiment differs from the previous embodiment in that the motor braking pressure is guided to the liquid chamber 21 of the constant horsepower control valve, and the motor braking pressure is guided directly to the liquid chamber 29 from the shuttle valve 12 via the electric ratio pressure reducing valve 23. are the same, and the effects are the same.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, a predetermined pressure reduction ratio is set between the hydraulic pressure switching valve and the constant horsepower control valve so that when the lowering load exceeds the rated load, the lowering can be performed under constant horsepower control. Since a constant ratio pressure reducing valve is provided, there is no need for a safety valve and a sequence valve for preventing an abnormal increase in motor braking pressure as in the conventional case. Therefore, even when lowering an excessive load, there is no noise or heat generated due to the operation of the safety valve, and all the hydraulic fluid from the hydraulic pressure source can be supplied to the variable displacement motor, improving cargo handling efficiency.

Furthermore, since safety valves and sequence valves are not required, it helps to reduce costs.

[Brief explanation of drawings]

Figures 1 and 2 are hydraulic circuit diagrams of embodiments of the present invention, Figure 3 is a chart showing the relationship between load and load hoisting/lowering speed in the present invention, and Figure 4 is a hydraulic pressure diagram of a conventional device. circuit diagram,
FIG. 5 is a chart showing the relationship between load and load hoisting/lowering speed in a conventional device. 1. Hydraulic pressure source, 3. Directional switching valve, 4. Variable displacement motor, 5. Counter balance valve, 14. Hydraulic pressure switching valve, 6. Constant horsepower control valve, 23. Constant Specific pressure reducing valve, 24.
・Volume control cylinder.

Claims (1)

[Claims] A variable displacement motor connected to a hydraulic pressure source via a directional valve is provided with a counterbalance valve and a constant horsepower control valve that controls the displacement control cylinder of the variable displacement motor. A constant horsepower hydraulic winch, characterized in that it is equipped with a hydraulic pressure switching valve that directs the motor supply pressure when hoisting a load as pressure and the motor braking pressure when lowering a load via a constant ratio pressure reducing valve. Control device.