JPH02186020A - Restraining and stabilizing circuit for running vibration of wheel type construction machine - Google Patents

Abstract

PURPOSE:To protect an accumulator by closing an opening/closing valve so as to stop supply of pressure oil to a vibration restraining circuit, when pressure in the oil chamber on the head side of a lift cylinder rises and pressure in the vibration restraining circuit is over a prescribed pressure. CONSTITUTION:When a drilling work is performed while closing a main switch 6, a soft cylinder 8 is loaded. When pressure in pipe lines 15a, 33, 42 rises over a prescribed pressure as the result, a pressure switch 4 is actuated to supply current from an electric wire 40 to a wire 41, and brake contacts 3b, 3c are opened. Nextly, regardless of the condition of a make contact 2, all signals from a controller 1 to an opening/closing valve 17 and a second changeover valve 31 are stopped. When the main switch 6 is opened, the condition is same as the condition of no work of a vibration restraining device and the main switch 6 is unnecessary to be opened at each time of drilling work. Consequently, an accumulator 19 can be protected and efficiency of the drilling work can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention provides for a system in which the base end of a working device protruding from a vehicle body is pivoted to the vehicle body so as to be movable up and down, and the vibrations are suppressed hydraulically! Is it possible to prevent running vibrations in non-buffered, wheeled construction machinery that is supported by a hydraulic cylinder with an I< position? This invention relates to a hydraulic circuit that automatically prevents a working device from descending under its own weight when switching between activation and deactivation of a C position, and also protects equipment.

Conventional technology Conventionally, a vibration suppressing device is installed in the load side circuit of a hydraulic cylinder that supports a working device that protrudes from the vehicle body of a wheeled construction machine, so that it can be opened and closed by an on-off valve, and vibration is generated. The vibration suppression device was operated only while the vehicle was running, intervening in the load g4 line of the hydraulic cylinder.

For example, as a typical example of a heavy-wheeled construction machine, a wheeled tractor-shovel as shown in FIG. In this way, the working device 7 of the wheeled tractor excavator protrudes further forward than the front axle, and its weight ratio is large. , vibration of the aircraft is likely to occur.

Absorb the vibration energy at this time and make it into damped vibration, and the aircraft! c<For the purpose of stabilization, the load side pipe 15α of the lift cylinder 8 that supports the working device 7 is connected to the branch pipe 16
The working device 7 is connected to the vibration suppressing device 20 consisting of the throttle valve 18α, the slow return valve 18 consisting of the check valve 1B4, and the accumulator 19.
vibrates separately from the vehicle body, leading to damped vibration.

On the other hand, the wheeled tractor excavator not only travels, but also places the packet of the working device 7 on the ground, uses the forward force of the machine to dig the cutting edge into the earth and sand, fills the packet with earth and sand, and lifts it up with the dump cylinder 9. There are many operations in which the entire working device 7 is lifted by the lift cylinder 8, adjusted to an appropriate height at another point, and the dump cylinder 9 is operated again to dump the sand. During such excavation and planting work, the traveling speed during planting and tamping is either extremely low or stopped, and no vibration occurs, rather the packet is attached to the vehicle body. Accurate and safe work cannot be performed unless the lift cylinder 8 is held securely, so in such a case, the lift cylinder 8 must be isolated from the vibration suppressor 20. On the other hand, when traveling, the lift cylinder 8 must be in communication with the vibration suppressor 20. Therefore, a switching valve 17 is interposed in the middle of a branch pipe 16 that communicates a pipe 15α leading to a head side oil chamber 8α, which is the load side of the lift cylinder 8, and the vibration suppressing device 20. They were selectively operating switch 6 installed near the machine.

During a series of operations such as digging, moving, loading, and moving during work, the invention or problem to be solved must be carried out at least twice, and more times depending on the distance traveled, the road surface, and obstacles. Moreover, opening and closing operations of communication between the lift cylinder and the vibration suppression device become frequent. To specifically describe the situation at this time,
When loading earth and sand into the packet of the working device 7, the switch 6 is opened and the on-off valve 17 is set to IP, the A position in FIG. 5, so that the pipe 15α and the vibration suppressing device 20 are cut off. In this state, when loading earth and sand into the packet and lifting the working device 7, the oil chamber 8a of the lift cylinder 8
The circuit pressure becomes high in proportion to the load on the packet.Next, when all earth and sand excavation operations have been completed and travel is started, switch 6 is turned on to suppress vibrations during travel.
When the circuit is closed and the vibration suppressing circuit 20 and the pipe line 15α are communicated, since the pressure in the accumulator 19 has not reached the pressure of the pipe line 15α, a part of the pressure oil in the front side oil chamber 8a of the lift cylinder 8 is Flows into the accumulator 19 through the pipe 15Q, the branch pipe 16, the B position passage of the on-off valve 17, and the slow return valve 18, so the working device 7 is lowered relative to the vehicle body. In addition, when dumping earth and sand at a predetermined location after the next move, to prevent the vehicle from shaking, the switch 6 is opened again to cut off communication between the conduit 15α and the vibration suppressor 20. , the dump cylinder 9 is operated to discharge the packet of earth and sand.

During the above-mentioned series of operations, it is often very dangerous that the working device lowers slightly at the moment the switch 6 for activating the vibration suppressor 20 is closed in order to scoop up and move the earth and sand into the packet. Therefore, as shown in FIG. 6, a relay circuit 44 and a vibration suppressor are installed between the receiving part of the on-off valve 17 and the switch 6! The pressure in the pipe line 33 leading to the lift cylinder 8 is transferred to the pipe line 15α leading to the head side oil chamber 8α of the lift cylinder 8.
When the pressure in the pipe 33 is lower than that in the pipe 15α, the hydraulic pump 11 is closed until the pressure in the pipe 15α is approximately equal to or higher than that in the pipe 15α. A first switching valve 30 that preferentially supplies discharged pressure oil to the pipe line 33 and a second switching valve 31 that receives a command from the relay circuit 44 and operates the first switching valve are provided. Even if the pipe line 15 is closed, the pressure accumulated in the vibration suppressing device 20 or
An electric/hydraulic circuit is provided in which the on-off valve 17 will not open unless α is the same as that of the conduit 16.

However, the lift cylinder 8 generates pressure in the side oil chamber 8α in response to the static and dynamic loads of the entire working device 7, and during normal excavation, transportation, etc. Hydraulic circuits are designed to accommodate these high pressures.

For example, when excavating with the dump cylinder 9, the reaction force of the excavation resistance generates a pressure in the oil chamber 8α that is much higher than the static weight load pressure of the working device 7 containing the work object. If excavation work or traveling is performed with the switch 6 closed, the accumulator 19 in the vibration suppressing device 20 as described above will accumulate pressure corresponding to the maximum pressure generated in the oil chamber 8α, which will shorten the life of the accumulator. becomes shorter.

In view of this point, when the traveling vibration suppression stability circuit is operated, pressure oil flows into the achievator of the vibration suppression device, and the pressure thereof is approximately equal to the pressure in the head side oil chamber of the lift cylinder. After that, opening the on-off valve that communicates with the vibration suppression device in the oil chamber is the same as in the past, or during excavation work, as mentioned above, the pressure in the oil chamber on the head side of the lift cylinder increases. When the pressure in the vibration suppression circuit reaches a predetermined pressure or higher, the on-off valve is automatically closed and the supply of pressure oil to the vibration suppression circuit is also stopped to protect the accumulator. The object of the present invention is to improve the efficiency of excavation work, and to automatically provide a running vibration suppressing and stabilizing circuit during normal running after the excavation work room Y.

Means for Solving the Problems In order to solve the above problems, the present invention takes the following measures. In other words, a.) An on-off valve that is located in the middle of the communication pipeline between the vibration suppression device and the load-side oil chamber of the lift cylinder and opens the internal oil passage in response to an external signal.

) Located in the middle of the discharge side pipe line of the hydraulic pump, only when a pressure higher than the accumulated pressure of the accumulator in the vibration suppression device acts on the receiving part, the discharge pressure oil of the hydraulic pump is transferred to the vibration suppression device. f51 switching valve which switches to supply the
2.) a pressure detection device, a pressure switch, a break contact, a make contact, etc.; (e) A control means equipped with a function of emitting signals to the receivers of the first switching valve and the second switching valve; A switch is provided for each.

) The signal emitted by the control means is supplied to the receiving part of the second switching valve when the means commands the operation execution, but the signal is sent to the receiving part of the second switching valve, but the signal is not transmitted to the vibration suppressing device guided by the pressure detecting device. When the pressure becomes approximately equal to or higher than the load side pressure of the lift cylinder, the signal to the receiving part of the ui2 switching valve is stopped, and at the same time, a signal is supplied to the receiving part of the opening/closing valve, and furthermore, the vibration suppressing device When the internal pressure exceeds a predetermined pressure, a function is provided in which all signals to the receiving section of the on-off valve and the second switching valve are stopped.

When the switch for the operation signal is closed and the v control means is put into the operating state, the accumulated pressure in the accumulator of the vibration suppression device guided by the pressure detection device or the standard load pressure of the lift cylinder is higher than the While low, the signal from the control means is supplied only to the second switching valve.

Therefore, the on-off valve maintains the closed state, and the pressure in the load-side oil chamber of the lift cylinder is reduced to the first uJ by the operation of the second switching valve.
The discharge pressure oil of the hydraulic pump passes through the if switching valve and flows into the accumulator.Next, when the pressure in the accumulator and the pressure in the load side oil chamber of the lift cylinder become approximately the same pressure, the pressure detection device The control means is operated by the internal make contact and break contact to control the second
Stops the signal to the switching valve and supplies a signal to the on-off valve. As a result, the pipe line leading to the load-side oil chamber of the lift cylinder communicates with the vibration suppression device having an accumulator stored at approximately the same pressure as this pressure, via the internal passage of the on-off valve, so that the on-off valve is The vibration suppression effect of the vehicle body can be obtained by raising the working equipment to the required height using a lift cylinder and traveling without lowering the working equipment at the moment the circuit is opened.

Next, while the control means is in operation, the pressure in the load-side oil chamber of the lift cylinder approaches the set maximum pressure due to, for example, excavation work with one working device or an abnormal load on the working device from the outside. On the other hand, making the maximum allowable pressure of the accumulator of the vibration suppression device that is communicated with °C through an on-off valve to withstand high pressure not only becomes expensive, but also poses a problem of durability. In such a case, in the present invention, the conduit leading to the vibration suppressor is led to a pressure switch constituting the control means, and when the pressure switch is applied with a pressure higher than a predetermined value, a signal is sent through this to the break contact. The control means includes an on-off valve, a second
No signal is provided to any of the switching valves.

Therefore, even if you perform excavation work with the signal switch closed, the accumulated pressure in the accumulator will not increase abnormally, and the working equipment will not rotate relative to the vehicle body. Excavation work will be carried out.

In addition, when the signal switch is opened and the operation of the control means is stopped, the signal is not supplied from the means to the on-off valve and the second switching valve, so the characteristics of the original wheel-type construction machine are not met. Needless to say, the residue will be given to you.

Example Embodiments of this invention will be described based on the drawings.

FIG. 91 is an electrical/hydraulic system diagram when a wheeled tractor excavator, which is a typical example of a wheeled construction machine, is provided with a normal vibration suppression device and a traveling vibration suppression stabilization circuit according to the present invention.

In the figure, 8.9 is a lift cylinder and a dump cylinder for working equipment, 1O is a tank, 11 is a hydraulic pump for operating the working equipment in a hydraulic power unit, and 12 is a hydraulic switching valve for the dump cylinder 9. The oil pressure switching valve 12 is connected to the head side oil chamber 9α of the dump cylinder 9 via pipes 14cL and 146.

The lot side oil chamber 9a is connected, and 13 is the lift cylinder 8.
It is a hydraulic switching valve for use, and a pipe, a passage 15 is connected to the hydraulic switching valve 13.
α, head side oil chamber 8 of lift cylinder 8 via 15F
α, the lot side oil chamber 8a is connected, and furthermore, in the lift cylinder 8, the load side oil chamber by one working device,
That is, a branch pipe 16 is provided in the middle of a pipe 15α connected to the head side oil chamber 8α, and this branch pipe 16 is connected to a slow return valve 18 consisting of a throttle valve 18α and a check valve 18Δ via an on-off valve 17. This slow return valve 18 is further connected to an accumulator 19.

The above-mentioned on-off valve 17 normally closes the first branch pipe 16 by the biasing force of a built-in spring, and when an electric signal is input to its receiving part, it opens and closes the branch pipe 16 as a slow return valve. 18 and an accumulator 19.
1120. Further, as the accumulator 19, a plug-type accumulator is usually used, and depending on the load size, work conditions, installation space, etc., it may be one or more, or it may be one or more including the on-off valve 17 and the vibration suppressor 20. They may be used in various combinations.

21 is a main relief valve, 22, 23 and 24 are overload relief valves for circuits communicating with the pipes 14a, 144 and 15Q, respectively, and 25, 26, 27 and 28 are check valves for preventing cavitation.

Furthermore, the pressure oil of the hydraulic pump ll is
In the middle of the pipe line 32 flowing into the hydraulic switching valve group consisting of
Of the pipes 37 and 41 leading to the receiving section, when pipe 37 has a higher pressure, the position is C, and when pipe 41 has a higher pressure, the position is D.
When the wSl switching valve 30 is in the C position, the pressure oil discharged from the hydraulic pump 11 passes through the check valve 29 and the conduit 33 to the vibration suppressor 2.
When the check valve 29 is switched to the 0 and D positions, the passage to the check valve 29 is blocked and the passage is led to the conduit 32. 3
Reference numeral 1 designates a second electromagnetic switching valve, which is connected to the receiving section by an electric wire 38 to a control means l, which will be described later.
position, allowing the pipe line 37 to pass through the tank lO, but when a signal is supplied, it switches to the F position, allowing the pipe line 37 to pass through the pipe line 36 branched from the pipe line 15Q. Also,
Reference numeral 39 is an electric wire, which connects the above-mentioned control means l and the receiving section of the on-off valve 17, and 6 is a main switch that connects and disconnects the power to the control means l.

Then, 1 is the control means mentioned above, and to show one example, as in the first rg, a pressure detection device 5 that interlocks the make contact 2, a pressure switch 4, a break contact 3α,
34.3c etc. The pressure detection device 5 is provided with two divided oil chambers, and each oil chamber is led to a pipe line 34 branching from the pipe line 15α and a pipe line 35 branching from the pipe line 33. When the pressure in the line 35 becomes approximately equal to or higher than the pressure in the line 34, the built-in make contact 2, which had been open until then, is closed, and the line 33 is branched to the pressure switch 4. A conduit 42 is led through the pressure switch, and when the pressure in the conduit 42 exceeds a predetermined pressure or becomes abnormally high, the internal electric circuit of the pressure switch is closed.

Also, 3α, 34, and 3c are all break contacts,
The internal electrical circuit is normally closed, but opens when energized. Note that 40 and 41 are all electric wires and constitute an electric circuit within the control means 1.

Next, the operation of the present invention having the above configuration will be explained.

When using the illustrated wheeled tractor excavator without activating the normal running vibration suppression circuit, the main switch 6
Since it is sufficient to operate with the main switch 6 open, a detailed explanation of the operating state at that time will be omitted, and the main switch 6 will be left closed.

We will only explain the operation when performing work such as traveling or digging.

First, when the traveling vibration suppression device starts operating during traveling, the engine (not shown) drives the hydraulic pump 11, and the lift cylinder 8 moves the working device 7 against its own weight or the load of the loaded object. Assuming that the state is maintained, the load side oil chamber 8α and the pipe line 15a leading thereto.
coercive force is generated. Therefore, if the main switch 6 is closed while the accumulated pressure in the accumulator 19 of the vibration suppression device δ20 is much lower than the force inside the pipe 15α, the pressure in the pipes 33 and 35 will be lower than that in the pipe 15α. 15α,
34, the make contact 2 in the pressure detection device 5 is open, so the main switch edge 6. Since the power supply connected to the electric wire 40 is not connected to the electric wire 39, the on-off valve 17 maintains the on position. On the other hand, the power source of the electric wire 40 is connected to the break contacts 3α, 3 which are arranged in series and are closed.
(.

Since the signal passes through the electric wire 3B and reaches the receiving part of the second switching valve 31, the second switching valve switches from the E position to the F position, and as a result, the pipes 36 and 37 are brought into communication. At this time,
The pressure in the pipe line 41 is connected to the pipe line 33 and is lower than the pressure in the pipe line 36, so the rtS1 switching valve 30 is in the C position, and the pressure oil discharged from the hydraulic pump 11 is in the C position passage of the first switching valve 30, the check valve 29, It passes through the pipe line 33 and the slow return valve 18 and flows into the accumulator 19, increasing the internal pressure of the vibration suppressing device 20. Accordingly, when the pressure in the conduit 35 becomes approximately equal to or exceeds the pressure in the conduit 34, the pressure detection device 5 is activated to close the built-in make contact 2. Then, the power of the electric wire 40 passes through the meter contact 2 and the break contact 3C, and acts as a signal on the receiving part of the on-off valve 17 via the electric wire 39 to switch the valve from the A position to the 8 position. At the same time, the break contact 3α is opened, and the signal to the electric wire 38 is stopped.
The second switching valve 31 switches from the F position to the E position, and the first switching valve 30 switches from the C position to the D position. It is natural that the flow into the group and the operation of the first working device 1117 would be difficult, but at the moment when the on-off valve 17 is switched to the B position, the pressure around 1 is almost equal, so the intention of the first worker is On the other hand, the working equipment does not descend.

Furthermore, when performing excavation work with the main switch 6 closed, an excessive load is applied to the lift cylinder 8 due to the excavation reaction force of the working device 7 or an unexpectedly excessive external force, and the pipes 15α and 33.42 are When the pressure exceeds a predetermined pressure, the pressure switch 4 is activated and the power of the electric @ 40 passes through the electric wire 41 and opens the break contacts 34, 3c, so regardless of the state of the make contact 2, the control device l
From, on-off valve 17. All signals to the second switching valve 31 are stopped, which is the same as when the main switch 6 is opened, that is, when the vibration suppression device is not activated. Even during excavation work, etc., the main switch 6 can be opened each time. The accumulator is also protected.

21& is an electric/hydraulic system diagram showing a second embodiment of the present invention, or the hydraulic pump 11 shown in the first embodiment is a hydraulic pump for operating a working device and a hydraulic pump for filling pressure oil into a vibration suppressing device. This is an embodiment in which a hydraulic pump 43 is separately provided independently of the hydraulic pump 11 in order to further smooth the operation.
Both effects are similar to the first embodiment.

FIG. 3 shows another embodiment 1α of the control means l in FIGS. 1 and 2. , 4A yarn system. This system diagram and that shown in Fig. 1 differ in the arrangement and combination of the break contacts 46α, 46f and the make contacts 2, 47, and their operation is based on a signal from the main switch 6, which is a signal opening/closing operation. Power is supplied to the pressure switch 4 and the break contact 46α through the electric wire 40, and in the illustrated state, the power is supplied as a signal to the break contact 46a and the break contact 4.
When the pressure in the conduit 35 is equal to or exceeds the pressure in the conduit 34, the make contact 2 of the pressure detection device 5 closes. The make contact 47 is closed, sending a signal to the wire 1139, and the break contact 46 is opened, cutting off the signal to the wire 38.

To the east, as described in the operation of the previous embodiments,
When the pressure in the pipe 42 rises above a predetermined value, the pressure switch 4 is closed, and as a result, the break contact 46α is opened, and all electrical circuits other than the pressure switch 4 are cut off. All signals to are interrupted or
When the pressure switch 4 automatically returns, the control means lα is activated again.
starts operating.

As mentioned above, the control means l shown in FIGS. 1 and 3.

1α is a part of an example in which a power supply is used as a signal medium, and a pressure detection device, a pressure switch, and various contacts are combined, and ``C'' is a control means in this invention. For example, it is not limited to only
The on-off valve 17, the second switching valve 31, the pressure detection device 5 in the control means 1, the pressure switch 4. Break contact 3
α, 3(.

In combination with 3c, 46α, 46shi, make contact 2.47, etc., their characteristics or reverse characteristics may be used, or there is no problem even if the signal medium is replaced with a fluid such as hydraulic pressure or pneumatic pressure in addition to electricity. The key point is that switching to the running vibration suppression circuit of the wheeled construction machine can be realized by an easy operation, and when the running vibration suppression circuit is in operation, the accumulated pressure of the accumulator 19 is equal to or lower than that of the lift cylinder 8. When the pressure is lower than the load-side oil chamber pressure, the pressure oil discharged from the hydraulic pump 11 or 43 is supplied to the vibration suppression device 20 with priority until the pressure becomes almost the same, and when the pressure becomes almost the same, In addition to automatically opening the on-off valve 17 and at the same time stopping the flow of pressure oil into the vibration suppression device by the hydraulic pump E, if for some reason the pressure inside the vibration suppression device becomes abnormal above a predetermined pressure. When this occurs, the second switching valve 31 is automatically placed in a position where the on-off valve 17 is closed and the pressure oil of the hydraulic pump 11 or 43 is stopped from flowing into the vibration suppressing device 20 side. Any control means that emits such a signal may be used.

Effects of the Invention When the stability circuit according to the present invention is added to the running vibration suppression circuit of the hydraulic means provided in a wheeled construction machine, the hydraulic circuit in the normal working state can be switched to a circuit that can obtain a vibration suppression effect. When the operation is performed, the accumulator in the vibration suppression device is automatically replenished with pressure oil from the hydraulic pump until the pressure is almost equal to the pressure in the load side oil chamber of the lift cylinder for supporting the work equipment, and then the vibration is suppressed. Since the suppression device is activated, the work equipment does not descend against the operator's will during switching, providing safe free rotation and good ride comfort. If the pressure in the load-side oil chamber of the lift cylinder for supporting work equipment reaches an abnormal pressure higher than the predetermined pressure allowed by the accumulator due to work or other reasons, the connection between the load-side oil chamber and the vibration suppression device is automatically shut down. The pipeline between the two is cut off, and at the same time, the supply of pressure oil from the hydraulic pump to the vibration suppression fill device is also stopped, protecting the accumulator, and the work equipment is integrated with the aircraft via the lift cylinder. Therefore, it is possible to improve the durability of the vibration suppression device, simplify J-1 driving operations, and improve safe driving.

[Brief explanation of the drawing]

Fig. 1 shows a first embodiment of the present invention, Fig. 2 shows an electric/hydraulic system diagram showing a second embodiment, and Fig. 3 shows another embodiment of the control means in Figs. 1 and 2. Electrical system diagram, 4th
The figure is an external side view of a wheeled tractor excavator, Figure 5 is a main electrical and hydraulic system diagram showing a conventional general running vibration suppression circuit installed in a wheeled tractor excavator, and Figure 6 is a further version of Figure 5. It is an improved conventional electric/hydraulic system diagram. 1.1 (L... Control means 2...
・・・・・・・・・Make contacts 3α, 3&, 3c
...... Break contact 4 ...... Pressure switch 5 ...... Pressure detection device 17 ...... Opening/closing valve 20 ...... - Vibration suppressor 30...
...... 1st switching valve... 2nd switching valve or higher

Claims (1)

[Claims] A wheel-type construction machine in which the base end of a working equipment support member is pivotally supported on the vehicle body and supported by a lift cylinder, in which a pipe leading to a load-side oil chamber of the lift cylinder is opened by the action of a signal. In a hydraulic traveling vibration suppression circuit connected to a vibration suppression device via an on-off valve, a pressure higher than the pressure inside the vibration suppression device is provided in the middle of a pipe connecting a hydraulic power source and a pipe on the upstream side of the on-off valve. A first switching valve that guides the hydraulic pressure source to the upstream pipe line only when pressure acts on the receiving part, and a pipe line that leads to the receiving part of the first switching valve that is opened when a signal acts on the receiving part. When a signal is input through the second switching valve that communicates with the pipe leading to the load side oil chamber of the lift cylinder and the signal switch that can be opened and closed from the driver's seat,
A signal is output to the receiving section of the second switching valve, and when the pressure inside the vibration suppression device is approximately equal to or higher than the pressure in the load side oil chamber of the lift cylinder, a signal is output to the receiving section of the opening/closing valve. A function that cuts off the signal output circuit to the receiving section of the 2-way switching valve, and further cuts off the signal output circuit to the receiving section of the on-off valve and the 2nd switching valve when the pressure inside the vibration suppression device exceeds a predetermined pressure. A running vibration suppression stability circuit for a wheeled construction machine, comprising a control means having the following.