JP2000230505A - Hydraulic tuning circuit for construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic tuning circuit for a construction machine capable of preventing the possibility of impairing of the tuning function of a plurality of hydraulic motors, and preventing the lowering of the pressure of the hydraulic oil in a hydraulic oil outflow pipe by quickly closing a valve, when a tuning pipe is broken, for preventing a hydraulic motor from being damaged. SOLUTION: Pilot check valves 6 which opens when the force on the basis of the total pressure of the pressure of the hydraulic oil in a tuning pipe and the pressure of the hydraulic oil in a hydraulic oil inflow pipe 2 becomes stronger than the force on the basis of the pressure of the hydraulic oil in a hydraulic oil outflow pipe 3, are respectively mounted on the connection sides with the hydraulic oil outflow pipes 3, of a tuning pipe 5 for communicating the hydraulic oil outflow pipes 3 respectively comprising the counter balance valves 4 of the hydraulic motors 1, 1, and their primary port 6c side and secondary port 6d side are made to communicate with each other by means of a port communication pipe 8, comprising a throttling 9 for instantaneously closing the pilot check valves when the tuning pipe 5 is damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a hydraulic tuning circuit of a construction machine, and more particularly, to an operation of a plurality of hydraulic actuators operated by supplying and discharging hydraulic oil without impairing the synchronizability of these hydraulic actuators. The present invention belongs to the technical field of a hydraulic tuning circuit for a construction machine that can safely stop the hydraulic actuator even if a tuning path that connects hydraulic oil outlet paths from which oil flows out is broken.

[0002]

2. Description of the Related Art As a hydraulic tuning circuit for a construction machine, for example, a circuit disclosed in Japanese Utility Model Publication No. 64-1345 is known. Hereinafter, a hydraulic tuning circuit of a construction machine according to a conventional example disclosed in Japanese Utility Model Publication No. 64-1345 will be described with reference to FIG.

That is, in order to synchronize and drive a plurality of hydraulic actuators 51 having a counterbalance valve 54, a hydraulic oil outflow pipe 53 which is a hydraulic oil outflow passage through which hydraulic oil flows out from the hydraulic actuators 51, 51. , 5
A tuning tube 55 is provided, which is a tuning path that allows three comrades to communicate with each other. A fuse valve 61 having a configuration to be described later is interposed on each side of the tuning pipe 55 connected to the hydraulic oil outflow pipe 53. This fuse valve 61
It is provided for the purpose of safely stopping the hydraulic actuators 51, 51 when the tuning tube 55 is damaged. More specifically, the fuse valve 61
The force generated by the pressure difference between the pressure of the hydraulic oil in the tuning pipe 55 and the pressure of the hydraulic oil in the hydraulic oil outflow pipe 53 is caused by the set pressure of the spring 72 provided in the fuse valve 61 and the hydraulic actuator 51, The valve is configured to close when a force greater than a force obtained by adding a force generated by the pressure of the hydraulic oil in the hydraulic oil inflow pipes 52, 52, which is a hydraulic oil inflow passage for flowing the hydraulic oil into the hydraulic fluid 51, is provided. I have.

Accordingly, a slight differential pressure (pressure of hydraulic oil in the tuning pipe 55 and hydraulic oil outflow 5
3), the fuse valves 61, 6
Since the valve 1 does not close, the synchronization of the plurality of hydraulic actuators 51, 51 is not hindered.

[0005]

The hydraulic tuning circuit for a construction machine according to the above conventional example is considered to be useful as such. However, there are still problems to be solved as described below. That is, the fuse valve 61 is well understood from FIG. 3 in order to detect the differential pressure (the pressure difference between the pressure of the hydraulic oil in the tuning pipe 55 and the pressure of the hydraulic oil in the hydraulic oil outlet pipe 53). In addition, the tuning pipe 55 and the hydraulic oil outflow pipe 53 are in communication with each other through the throttle 73 even in the fully opened state. Therefore, for example, if there is a characteristic difference in the counterbalance valve 54 (it is impossible to completely eliminate it) and hydraulic oil flows in the tuning tube 55, a differential pressure is generated due to the presence of the throttle 73. I will. That is, although the purpose of the tuning tube 55 is to synchronize the plurality of actuators 51, 51, a differential pressure is generated in the fuse valve 61, so that the loads acting on the actuators 51, 51 are biased. However, there is a problem to be solved that the purpose of the original tuning circuit may be impaired.

Further, there is another problem to be solved in that the fuse valve 61 has a complicated structure (multi-port and special) and the manufacturing cost of the hydraulic tuning circuit increases.

Accordingly, an object of the present invention is to provide a method for safely operating a plurality of actuators when a tuning path that connects hydraulic oil outlet paths through which hydraulic oil flows out from the actuators is broken without impairing the synchronizability of the actuators. An object of the present invention is to provide a hydraulic tuning circuit of a construction machine that can be stopped.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and accordingly, the means adopted by the hydraulic tuning circuit for a construction machine according to claim 1 of the present invention is as follows.
A plurality of hydraulic actuators for driving the work machine are provided, and each of these hydraulic actuators is provided with a hydraulic oil inflow passage through which hydraulic oil flows in from a direction switching valve and a counterbalance valve, and hydraulic oil outflow through which hydraulic oil flows out And the hydraulic oil outflow passages communicate with each other in a synchronized manner in a hydraulic tuning circuit of a construction machine, wherein the hydraulic oil outflow passage is connected to the hydraulic oil outflow passage on each side of the tuning passage connected to the hydraulic oil outflow passage. The valve is opened when the force based on the total pressure of the hydraulic oil pressure in the oil inflow path and the hydraulic oil pressure in the tuning path becomes larger than the force based on the hydraulic oil pressure in the hydraulic oil outflow path. The valve is interposed.

According to a second aspect of the present invention, there is provided a hydraulic tuning circuit for a construction machine according to the first aspect, wherein the valve is an external drain type.
And a pilot-operated valve for preventing hydraulic oil flowing from the primary port from flowing out to the secondary port and preventing hydraulic oil flowing from the secondary port from flowing out to the primary port. I do.

According to a third aspect of the present invention, in the hydraulic tuning circuit for a construction machine according to the second aspect, the hydraulic actuator side is connected to the secondary port side of the valve. And a tuning port side is connected to a primary port side, and a pilot port is connected to the hydraulic oil inflow path.

According to a fourth aspect of the present invention, there is provided a hydraulic tuning circuit for a construction machine according to any one of the first to third aspects, wherein the hydraulic tuning circuit for a construction machine employs a hydraulic tuning circuit. It is characterized in that a port communication path for communicating the secondary port side and the primary port side of the valve is provided, and a throttle is interposed in the port communication path.

According to a fifth aspect of the present invention, there is provided a hydraulic tuning circuit for a construction machine according to any one of the first, second, third and fourth aspects. The cracking pressure of the valve is set to be lower than the cracking pressure of the counterbalance valve.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a hydraulic tuning circuit for a construction machine according to a first embodiment of the present invention will be described with reference to FIG. 1 (a) of a hydraulic tuning circuit diagram thereof and FIG. This will be described with reference to FIG.

Reference numeral 1 shown in FIG. 1A denotes a hydraulic motor which is two hydraulic actuators. Each of the two hydraulic motors 1 is controlled from a hydraulic pump 21 by a pilot control valve 23, and A hydraulic oil inflow pipe 2 as a hydraulic oil inflow passage into which hydraulic oil flows is communicated via a 3-position 6-port direction switching valve 22, and a pilot pipe for controlling a counterbalance valve with which the hydraulic oil inflow pipe 2 communicates. 1
A counterbalance valve 4 whose valve opening is controlled by the inflow of hydraulic oil from 2 is interposed, and a hydraulic oil outflow pipe 3 which is a hydraulic oil outflow passage from which hydraulic oil flows out communicates.

The hydraulic motors 1 of the hydraulic oil outflow pipes 3 and 3 communicate with the counterbalance valve 4 via a tuning pipe 5 which is a tuning path. A valve having a configuration to be described later is interposed on each side of the tuning pipe 5 connected to the hydraulic oil outflow pipe 3. That is, this valve is of an external drain type and allows the hydraulic oil flowing from the primary port 6c to flow out to the secondary port 6d, while the primary oil 6c of the hydraulic oil flowing from the secondary port 6d flows. This is a pilot-operated valve that prevents flow to the side, that is, a commercially available pilot-operated check valve 6 having an extremely common configuration.

Each of the secondary ports 6d of the pilot type check valve 6 communicates with the connection side of the tuning pipe 5 with the hydraulic oil outflow pipe 3, and the primary ports 6c are connected to the tuning port 5d.
To communicate with each other. Each of the pilot ports 6e is connected to the other end of a check valve control pilot pipe 7, one end of which is connected to the hydraulic oil inflow pipe 2, and the drain port 6f is connected to the hydraulic oil tank 2
It communicates with 0.

That is, the pilot check valve 6
The force based on the total pressure of the hydraulic oil pressure in the hydraulic oil inflow pipe 2 and the hydraulic oil pressure in the tuning path 5 becomes larger than the force based on the hydraulic oil pressure in the hydraulic oil outflow pipe 3. Is opened when the tuning tube 5 is normal.
If the next port 6c side and the secondary port 6d side are completely connected, but the portion of the tuning tube 5 connecting the primary ports 6c is broken, the check function is activated and the operation of the hydraulic motor 1 is started. It is configured so that the oil outflow side can be prevented from instantaneously reaching the atmospheric pressure state.

The secondary port 6d side and the primary port 6c side of each of the pilot type check valves 6 are communicated by a port communication passage 8 in which a throttle 9 is interposed. The reason why the port communication passage 8 having the throttle 9 interposed therein is provided is that the pressure of the hydraulic oil in the hydraulic oil outflow pipe 3 is reduced by the load for operating the normal hydraulic motor 1.
When the pressure of the hydraulic oil in the tuning tube 5 is too low, the pilot-type check valve 6 does not open even if the pilot pressure acts, and performs the tuning function. However, the presence of the throttle 9 causes the hydraulic oil outflow pipe 3 and the tuning pipe 5 to communicate with each other, and the pressure of the hydraulic oil in the hydraulic oil outflow pipe 3 and the pressure of the hydraulic oil in the tuning pipe 5 cancel each other. This is because the pilot type check valve 6 can be easily opened only by the pilot pressure. The throttle 9 may be configured to be built in the pilot check valve 6.

A connection between the connecting portion of the tuning pipe 5 of the hydraulic oil inflow pipe 2 and the hydraulic oil outflow pipe 3 and the counterbalance valve 4 is communicated by a relief pipe 10 having a relief valve 11 interposed therebetween. I have. Further, the cracking pressure of the pilot check valve 6 is set lower than the cracking pressure of the counterbalance valve 4. this is,
When the counterbalance valve 4 is opened and the operation of the hydraulic motor 1 is started, the pilot check valve 6 is already opened, and the aim is to enable the synchronized operation of the hydraulic motors 1 and 1. Things.

The operation of the hydraulic tuning circuit of the construction machine having the above construction will be described below. The pilot control valve 23 switches the direction switching valve 22 to supply the hydraulic oil discharged from the hydraulic pump 21 to the hydraulic oil inflow pipe 2. When flowing, the hydraulic oil flowing into the hydraulic oil inflow pipe 2 flows out into the hydraulic oil outflow pipe 3 via the hydraulic motor 1. Since the counter balance valve 4 is in a neutral and closed state, the pressure of the hydraulic oil in the hydraulic oil outflow pipe 3 increases, and the pressure of the hydraulic oil in the hydraulic oil inflow pipe 2 via the hydraulic motor 1 is increased. To rise. The hydraulic oil whose pressure has increased in the hydraulic oil inflow pipe 2 flows into the pilot type check valve 6 via the check valve control pilot pipe 7, and the pilot piston 6a [see FIG. ] To push up the poppet 6b to make the hydraulic oil outflow pipe 3 and the tuning pipe 5 communicate with each other.

The pressure of the hydraulic oil in the hydraulic oil inflow pipe 2 further increases, and when the increased hydraulic oil flows into the counter balance valve 4 via the counter balance valve control pilot pipe 12, the counter balance valve 4 Begins to open. Then, when the valve is opened, the pressures of the hydraulic oil in the hydraulic oil inflow pipe 2 and the hydraulic oil in the hydraulic oil outflow pipe 3 are both reduced, and the counter balance valve is operated in a closing direction.

By repeating such operations, the opening area of the counterbalance valve 4 and the pressure of the hydraulic oil in the hydraulic oil inflow pipe 2 are automatically adjusted, and the flow rate of the hydraulic oil passing through the counterbalance valve 4 determined by the opening area, That is, the flow rate of the hydraulic oil passing through the hydraulic motor 1 is determined, and the rotation speed of the hydraulic motor 1 is determined. Therefore, the hydraulic motor 1 rotates at this rotation speed. As described above, since the cracking pressure of the counterbalance valve 4 is set to be higher than the cracking pressure of the pilot check valve 6, the counterbalance valve 4 and the hydraulic oil in the hydraulic oil inflow pipe 2 are set. When the pressure is automatically adjusted, the pilot check valve 6 does not open or close due to a change in the pressure of the hydraulic oil in the hydraulic oil inflow pipe 2.

During the rotation of the hydraulic motor 1 as described above, the tuning pipe 5 is damaged, and the operating oil between the pilot type check valves 6 and 6 of the tuning pipe 5 leaks to reach atmospheric pressure. Then, the pressure on the side of the primary port 6c decreases, and it becomes impossible to maintain the open state only by the pilot pressure, so that the pilot check valves 6 and 6 are closed. Of course, the hydraulic oil in the hydraulic oil outflow pipe 3 flows out through the throttle 9, but if the throttle area of the throttle 9 is set to be sufficiently small, the pressure of the hydraulic oil in the hydraulic oil outflow pipe 3 suddenly decreases. Can be prevented, and the hydraulic motor 1 can be prevented from being damaged due to a sudden pressure drop on the hydraulic oil outflow side. And, for example, even when the hydraulic motor 1 is applied to a winch of a crane that winds and rewinds a wire rope that hangs a suspended load, it is possible to prevent a sudden drop of the suspended load.

As described above, when the hydraulic motor 1 is operated, the pilot check valves 6 and 6 are open and are not communicated with each other through the throttle as in the conventional art.
In addition to the fact that no differential pressure is generated in the pilot type check valves 6 and 6, the purpose of the original hydraulic tuning circuit is not impaired, the pilot type check valve 6 has an extremely general configuration. Therefore, there is also an economic effect that the cost is more advantageous than a fuse valve having a complicated configuration.

Next, a hydraulic tuning circuit of a construction machine according to a second embodiment of the present invention will be described with reference to FIG. 2 of the hydraulic tuning circuit diagram. However, the second embodiment differs from the second embodiment only in that the connection state of the tuning pipe 5 and the number of pilot check valves are different.
The same components as those in the first embodiment and those having the same functions are denoted by the same reference numerals, and differences will be described.

That is, the hydraulic tuning circuit of the construction machine according to the first embodiment connects the spring chamber of the counterbalance valve 4 interposed in one hydraulic oil outflow pipe 3 and the other hydraulic oil outflow pipe 3. A pilot type check valve 6 is interposed on the connection side of the tuning tube 5 with the other hydraulic oil outflow pipe 3, and a secondary port 6d side of the pilot type check valve 6 is connected to the primary port. The port 6c is communicated with the port 6c through a port communication passage 8 having a throttle 9 interposed.

An outflow pipe pressure measuring pressure sensor 13 is attached to one hydraulic oil outflow pipe 3, and a tuning pipe pressure measuring pressure sensor 14 is attached to the tuning pipe 5, respectively. The difference between the pressure of the hydraulic oil in the hydraulic oil outflow pipe 3 detected by the above and the pressure of the hydraulic oil in the tuning pipe 5 detected by the tuning pipe pressure measuring pressure sensor 14 is a predetermined fixed value. An alarm device (not shown) for notifying that the tuning tube 5 is broken when the value becomes larger than the value is provided.

According to the hydraulic tuning circuit for construction equipment according to the second embodiment, when the tuning pipe 5 is broken, the pilot check valve 6 is closed and the hydraulic motors 1, 1 cannot be driven in synchronization. However, the control of the directional control valve 22 by the pilot control valve 23
1 can be operated in a state close to normal operation,
The operator of the construction machine cannot notice that the hydraulic motors 1 and 1 cannot be synchronized or that the tuning tube 5 is damaged.

However, the pressure of the working oil in the working oil outlet pipe 3 detected by the outlet pipe pressure measuring pressure sensor 13 and the working oil in the tuning pipe 5 detected by the tuning pipe pressure measuring pressure sensor 14 are determined. When the pressure difference from the pressure becomes larger than a certain value, it is possible to know from the alarm device that the tuning tube 5 is damaged.
Embodiment 2 can stop the operation of the second embodiment.
The hydraulic tuning circuit for a construction machine according to the third embodiment can achieve the same effect as the hydraulic tuning circuit for a construction machine according to the first embodiment.

Of course, as described above, even if the tuning tube 5 is broken, the hydraulic motors 1, 1 can be operated in a state close to normal operation, so that the hydraulic motors 1, 1 can be prevented from being damaged. Even if the hydraulic motors 1 and 1 are applied to a winch of a crane that winds and rewinds a wire rope that suspends a suspended load, a sudden drop of the suspended load can be prevented.

[0031]

As described in detail above, claim 1 of the present invention
According to the hydraulic tuning circuit of the construction machine according to the present invention, the pressure of the hydraulic oil in the working oil inflow path and the The valve that opens when the force based on the total pressure of the hydraulic oil and the pressure based on the total pressure of the hydraulic oil in the hydraulic oil outflow passage becomes larger than the force based on the pressure of the hydraulic oil in the hydraulic oil outflow passage.

Therefore, when the tuning path is broken, the pressure of the hydraulic oil in the tuning path decreases, and the valve cannot be closed by the pressure of the hydraulic oil in the hydraulic oil inflow path alone, and the valve is closed. The valve prevents sudden decrease in pressure of the hydraulic oil in the hydraulic oil outflow passage, and prevents damage to the hydraulic actuator as in the conventional example. However, when the hydraulic actuator operates, the valve is opened. Unlike the conventional example, since there is no communication through the throttle, there is no possibility that a differential pressure is generated in the valve, and there is no danger that the original purpose of the hydraulic tuning circuit is impaired.

According to the hydraulic tuning circuit for a construction machine according to claim 2 or 3 of the present invention, the valve is of an external drain type and allows the hydraulic oil flowing from the primary port to flow to the secondary port. Since it is a pilot-operated valve that prevents the hydraulic oil flowing from the secondary port from flowing out to the primary port side, that is, a pilot-type check valve, it can be easily opened and has a small response delay. In addition to
This pilot-type check valve has a simpler configuration than the fuse valve of the hydraulic tuning circuit according to the conventional example, and has an economic effect that it is advantageous in terms of cost.

According to the hydraulic tuning circuit for a construction machine according to a fourth aspect of the present invention, a port communication path is provided for communicating the secondary port side and the primary port side of the valve, and a throttle is provided in the port communication path. Since the valve is mounted, the valve can be more easily opened, and the response delay is further reduced.

According to the hydraulic tuning circuit for a construction machine according to the fifth aspect of the present invention, the cracking pressure of the valve is set to be lower than the cracking pressure of the counterbalance valve. Before the start of the operation of the hydraulic actuator, the tuning operation of the hydraulic actuator is already enabled, and the tuning function is not impaired.

[Brief description of the drawings]

FIG. 1A is a hydraulic tuning circuit diagram of a construction machine according to a first embodiment of the present invention, and FIG. 1B is a sectional configuration explanatory diagram of a pilot-operated valve.

FIG. 2 is a hydraulic tuning circuit diagram of a construction machine according to Embodiment 2 of the present invention.

FIG. 3 is a hydraulic tuning circuit diagram of a conventional construction machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hydraulic motor 2 ... Hydraulic oil inflow pipe 3 ... Hydraulic oil outflow pipe 4 ... Counter balance valve 5 ... Tuning pipe 6 ... Pilot type check valve, 6a ... Pilot piston. 6b: Poppet, 6c: Primary port, 6d: Secondary port, 6e: Pilot port, 6f: Drain port 7: Check valve control pilot pipe 8: Port communication pipe 9 ... Restrictor 10: Relief pipe 11 ... Relief valve DESCRIPTION OF SYMBOLS 12 ... Pilot pipe for counter balance valve control 13 ... Pressure sensor for outflow pipe pressure measurement 14 ... Pressure sensor for tuning pipe pressure measurement 20 ... Hydraulic oil tank 21 ... Hydraulic pump 22 ... Direction switching valve 23 ... Pilot control valve

Claims (5)

[Claims] 1. A hydraulic machine comprising a plurality of hydraulic actuators for driving a working machine, each of which is provided with a hydraulic oil inflow passage through which hydraulic oil flows from a direction switching valve and a counterbalance valve, and the hydraulic oil is provided. The hydraulic oil outflow path that flows out is communicated in parallel with the hydraulic oil outflow path, and the hydraulic oil outflow path is connected to the hydraulic oil outflow path of the construction machine. In each case, the force based on the total pressure of the hydraulic oil pressure in the hydraulic oil inflow path and the hydraulic oil pressure in the tuning path is larger than the force based on the hydraulic oil pressure in the hydraulic oil outflow path. A hydraulic tuning circuit for a construction machine, comprising a valve that opens when the valve is opened. 2. The valve according to claim 1, wherein the valve is an external drain type, and the hydraulic oil flowing from the primary port side flows out to the secondary port side, and the hydraulic oil flowing from the secondary port side flows out to the primary port side. The hydraulic tuning circuit for a construction machine according to claim 1, wherein the hydraulic tuning circuit is a pilot-operated valve that prevents the occurrence of a hydraulic pressure. 3. The valve according to claim 1, wherein the hydraulic actuator side is connected to a secondary port side of the valve, the tuning path side is connected to a primary port side, and a pilot port is connected to the hydraulic oil inflow path. The hydraulic tuning circuit for a construction machine according to claim 2, wherein 4. The valve according to claim 1, further comprising a port communication passage communicating between the secondary port side and the primary port side of the valve, and a restrictor interposed in the port communication passage. Item 3. The hydraulic tuning circuit for a construction machine according to any one of Items 3. 5. The valve according to claim 1, wherein the cracking pressure of the valve is set to be lower than the cracking pressure of the counterbalance valve. Hydraulic tuning circuit for construction equipment as described.