JPH0759824B2 - Stabilization circuit for suppressing running vibration of wheeled construction machinery - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention This invention pivotally supports a base end portion of a working device protruding from a vehicle body in a vertically rotatable manner on the vehicle body, and additionally installs a hydraulic vibration suppressing device. Action of running vibration prevention device in non-buffer type wheel type construction machine supported by hydraulic cylinder
The present invention relates to a circuit capable of automatically excluding the working device from descending by its own weight when switching the inaction.

2. Description of the Related Art Conventionally, a vibration suppressor is provided in a load circuit of a hydraulic cylinder that supports a working device protruding from a vehicle body of a wheel-type construction machine. Only during the operation, the vibration suppressing device was operated so as to intervene in the load side pipe line of the hydraulic cylinder.

For example, as a typical example of a wheel-type construction machine, an embodiment of a main part of a traveling vibration suppressing device provided on a wheel-type tractor shovel as shown in FIG. 4 is as shown in FIG. Therefore,
When the wheeled tractor excavator travels on an uneven road surface, the working device 7 projects forward from the front axle, and its weight ratio is large. The axle is non-buffering type and is entirely supported by rubber tires. Therefore, vibration is likely to occur.

For the purpose of absorbing the vibration energy at this time to make a damping vibration, the load side pipe 15a of the lift cylinder 8 supporting the working device 7 is provided with a slow return valve 18 including a throttle valve 18a and a check valve 18b, and an accumulator 19. The working device 7 is vibrated separately from the vehicle main body by communicating with the vibration suppressing device 20 constituted by the branch pipe 16 so as to be damped.

On the other hand, the wheeled tractor excavator is not only for traveling, but also for lowering the bucket of the working device 7 to the ground, forcing the blade edge into the earth and sand with the forward force of the machine body, loading the earth and sand in the bucket, and raising it with the dump cylinder 9. In many cases, the entire working device 7 is lifted by the lift cylinder 8, the height is adjusted to an appropriate height at another point, and the dump cylinder 9 is operated again to dump the earth and sand. The traveling speed at the time of dumping or dumping in such excavation / loading work is at an ultra-low speed or in a stopped state, vibration does not occur, rather, the bucket is held integrally with the vehicle body. If this is not the case, accurate and safe work cannot be performed, so in such a case, the lift cylinder 8 must be isolated from the vibration suppression device 20, and, on the other hand, it is desirable that the lift cylinder 8 communicates with it when traveling. .

Therefore, a switch valve 17 is provided near the driver's seat with a switching valve 17 interposed in the middle of a branch pipe 16 that connects the vibration suppressor 20 with a pipe 15a that communicates with the head-side oil chamber 8a that is the load side of the lift cylinder 8. 6 was operated selectively.

Problems to be Solved by the Invention During a series of operations of excavation / movement / loading / movement during work, the movement distance becomes long at least twice,
Depending on the road surface and the condition of obstacles, repeat more times,
The opening / closing operation of the communication between the lift cylinder and the vibration suppression device becomes frequent. To specifically describe the situation at this time, when loading the soil of the bucket of the working device 7, the switch 6 is opened and the opening / closing valve 17 is set to the position A in FIG. The vibration suppressing device 20 is cut off. In this state, if the working device 7 for loading the sand into the bucket is raised,
The circuit pressure of the head side oil chamber 8a of the lift cylinder 8 becomes high in proportion to the load of the bucket. Next, when excavation of earth and sand is completed and traveling is started for movement, the switch 6 is closed to connect the vibration suppressing circuit 20 and the pipe 15a to each other to suppress vibration during traveling. Pipeline 15a
Since the pressure is not accumulated up to the pressure of, a part of the pressure oil in the head side oil chamber 8a of the lift cylinder 8 is partially connected to the pipe line 15a, the branch pipe line 16,
The working device 7 descends with respect to the vehicle body because it flows into the accumulator 19 through the B position passage of the opening / closing valve 17 and the slow return valve 18. Also, after the next movement, when dumping with earth and sand at a predetermined place, in order to prevent the vehicle from shaking, the switch 6 is opened again and the pipeline 15a and the vibration suppressing device 2 are opened.
The communication with 0 is cut off, and the dump cylinder 9 is operated to discharge the soil in the bucket. As a result, the load on the work device 7 decreases, and the pressure in the conduit 15a decreases accordingly. The movement of the vehicle is started from this state,
When the switch 6 is closed and the lift cylinder 8 and the vibration suppression circuit 20 are communicated with each other to suppress the vibration of the vehicle, the accumulator 19 has a head-side oil chamber corresponding to the load when the soil is fully loaded.
Since the high pressure of 8a is stored as it is, the on-off valve 17 is set to B
A part of the pressure oil accumulated at the moment of switching to the position flows into the head side oil chamber 8a of the lift cylinder 8, and the working device 7
As a result, the vehicle is lifted with respect to the vehicle body.

As described above, every time the opening / closing valve 17 is switched to the B position, the working device 7 slightly moves up and down against the driver's will, and it becomes difficult to maintain the accurate bucket position required during the work. It hinders quick and safe work.

In view of such a problem, the present invention keeps the pressure of the head side oil chamber of the lift cylinder and the accumulated pressure of the accumulator always the same when switching to the vibration suppression circuit state, and the working device is unnecessary for the vehicle body. It is intended to provide a stabilizing circuit that prevents vertical rotation.

Means for Solving the Problems In order to solve the above problems, the present invention takes the following means. That is, (a) intermediate the branch line of the discharge line of the hydraulic pump for working device with the first on-off valve that opens and closes the line leading to the vibration suppression device and the load-side oil chamber of the hydraulic cylinder supporting the working device. B) A second on-off valve that opens only when a signal acts on the receiving part, and a branch pipe line that is normally connected to the flow rate detection valve by the biasing force of the built-in spring However, when the holding pressure in the vibration suppression device, that is, the pressure higher than the accumulator accumulated pressure acts on the receiving part, it switches to cut off the connection to the flow rate detection valve and branch the pressure oil from the hydraulic pump. A switching valve, which is introduced into the vibration suppressing device via a passage, is provided in series.

C) A power supply is connected to the receiving portion of the first opening / closing valve through a switch, a limit switch that operates by the flow rate detection valve, and a make contact that operates by the limit switch and has a holding function.

D) A power supply is connected to the receiving portion of the second opening / closing valve through the switch and a break contact that opens the internal electric circuit only when the receiving portion of the first opening / closing valve is energized.

E) The pressure oil in the pipeline communicating with the load side oil chamber of the hydraulic cylinder supporting the working device is guided to the receiving portion of the switching valve by the pilot pipeline.

Action When a load is applied to the working device and the running is started, if the switch is closed and the working device is adjusted to the running posture, the power source acts on the receiving portion of the second opening / closing valve through the switch and the break contact, The second on-off valve opens to supply the pressure oil from the hydraulic pump to the switching valve. At this time, since the load side pressure of the hydraulic cylinder for supporting the working device acts on the receiving portion of the switching valve, this pressure is higher than the pressure in the vibration suppressing device, and therefore the hydraulic pump passing through the switching valve. Pressure oil flows into the vibration suppression device. As a result, when the pressure inside the vibration suppression device rises and becomes approximately equal to the load side pressure of the hydraulic cylinder, the switching valve switches, and the pressure oil flows into the flow rate detection valve and the flow rate detection valve and limit switch Since it is operated, the make contact is excited, the power source is connected to the receiving portion of the first opening / closing valve, the first opening / closing valve is opened, and vibration suppression with the load side oil chamber of the hydraulic cylinder supporting the working device is performed. The device is in communication with each other to exert a vibration suppressing effect during traveling. At this time, as described above, after the pressures of the oil chamber of the hydraulic cylinder and the vibration suppressing device are approximately the same, the first opening / closing valve is Since it is open, there is no momentary descent of the work equipment.

Note that the break contact is energized at the same time when the receiving portion of the first opening / closing valve is energized, the power supply to the receiving portion of the second opening / closing valve is cut off, and the branch pipeline is closed. Although the pressure oil inflow stops and the limit switch does not operate, the make contact is provided with a holding function.Therefore, unless the switch is opened, power is continuously supplied to the receiving part of the first on-off valve. To be done.

Embodiment An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an electric / hydraulic system diagram when a wheel type tractor shovel, which is a typical example of a wheel type construction machine, is provided with a normal vibration suppressing device and a traveling vibration suppressing stabilizing circuit according to the present invention.

In the figure, 8 and 9 are soft cylinders for work equipment, dump cylinders, 10 is a tank, 11 is a hydraulic pump for operating work equipment in a hydraulic power unit, 12 is a hydraulic switching valve for dump cylinders 9, The hydraulic switching valve 12 has pipes 14a, 14
The head side oil chamber 9a and the rod side oil chamber 9b of the dump cylinder 9 are connected via b, 13 is a hydraulic switching valve for the lift cylinder 8, and the hydraulic switching valve 13 is connected to the hydraulic switching valve 13 via pipelines 15a, 15b. The head side oil chamber 8a and the rod side oil chamber 8b of the lift cylinder 8 are connected. Further, in the lift cylinder 8, a branch pipe line 16 is provided in the middle of a pipe line 15a connected to the load-side oil chamber by the work device, that is, the head-side oil chamber 8a. It is connected via a valve 17 to a slow return valve 18 consisting of a throttle valve 18a and a check valve 18b, and this slow return valve 18 is further connected to an accumulator 19. The on-off valve 17 normally closes the branch pipe 16 by the urging force of a built-in spring, and when the electric signal is input to its receiving portion, it opens to open the branch pipe 16 and the slow return valve 18 Vibration suppressor 20 consisting of an accumulator 19 and
It is designed to communicate with. Also the accumulator
A prada type accumulator is usually used as 19, and may be a single or a plurality in view of the magnitude of the load, working conditions, installation space, etc., or may be a single or a plurality of combinations including the open / close valve 17, the vibration suppressing device 20, and the like. It may be used.

In addition, 21 is a main relief valve, and 22, 23, 24 are pipelines, respectively.
Overload relief valves of circuits communicating with 14a, 14b and 15a, and check valves 25, 26, 27 and 28 for preventing cavitation.

Further, the pressure oil of the hydraulic pump 11 flows into the hydraulic pressure switching valve group consisting of the hydraulic pressure switching valves 12 and 13 in the middle of the hydraulic pressure switching valve group.
0'is provided, and the branch line 30 'is provided with a vibration suppressing device 20 and an on-off valve 1
A check valve 36 for preventing backflow is connected in the middle of 7 and an opening / closing valve 34 and a switching valve 35 are provided in the pipe line 30 in series. The on-off valve 34 is normally in the C position and closes the conduit 30 by the urging force of the built-in spring, but when an electric signal acts on the receiving part via the electric wire 32, it switches to the D position, Open road 30. Further, the switching valve 35 is always in the E position by the urging force of the built-in spring so that the conduit 30 is connected to the conduit 30.
37, but the pressure oil of the pilot pipe line 31 communicating with the pipe line 15a acts on the receiving portion, and the pressure is applied to the pipe line 30 '.
If it is higher than that, it will switch to the F position,
The passage to 37 is blocked and the lines 30, 30 'are in communication.

Reference numeral 4 denotes a flow rate detection valve, in which two oil chambers on the left and right are formed by a piston a supported by a spring for maintaining neutrality, and communicate with the pipeline 37 and the tank 10, respectively, and both oil chambers on the left and right are inside the piston a. Since they communicate with each other through the throttle b, when there is a flow of pressure oil from the conduit 37 toward the tank 10, the piston a moves to the right in the figure, and when the flow of pressure right stops, the piston a moves. a is gradually returned to the neutral position.
Reference numeral 5 is a limit switch, which normally opens the electric wire 33, but when the piston a of the flow rate detection valve 4 moves to the right, it acts on the actuator of the limit switch 5 and is provided at a position where the electric wire 33 is closed. is there.

Further, 1 is a relay circuit having a make contact 2, a break contact 3, a switch 6 for opening and closing the power source, and the make contact 2 is normally open, but when the switch 6 is closed, the limit switch 5 When the electric wire 33 is once closed by means of this, power is continuously supplied to the electric wire 29 leading to the receiving portion of the on-off valve 17, and this state is maintained unless the switch 6 is closed, and the break contact 3 is normally closed. However, it is an electric circuit of a known technique that is designed to open while the electric wire 29 is energized regardless of whether the limit switch 5 is opened or closed.

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

When the wheel type tractor excavator is stopped, or when excavating and scooping earth and sand at an ultra-low speed, the switch 6 is left open and the hydraulic switching valves 12 and 13 for operating the work device 7 are operated to achieve the required operation. The open / close valve 1
Since no electric signal is applied to the receiving portions of 7,34, the positions A and C in the closed state are held in both cases. Therefore, the working device 7 is reliably supported by the lift cylinder 8 with respect to the vehicle body, and, like a normal machine, the hydraulic switching valve.
Accurate operation is performed according to the operation of 12, 13.

When the bucket is completely scooped with soil and the vehicle starts traveling on an uneven transportation path, the switch 6 is first closed and the hydraulic switching valves 12 and 13 are operated to adjust the traveling posture. During this time, the power source is switch 6, break contact 3, electric wire 32
Since it acts on the receiving part of the on-off valve 34,
Switches from the C position to the D position, and connects the conduit 30 to the switching valve 35. On the other hand, in the receiving portion of the switching valve 35, the pilot pipe line 31 is led from the pipe line 15a communicating with the head side oil chamber 8a of the lift cylinder 8, but this pressure is a value increased by the load after the sand and sand are scooped. Therefore, the switching valve 35 is already in the F position, and the pressure oil in the pipeline 30 is in the D position oil passage of the opening / closing valve 34, the F position oil passage of the switching valve 35, the check valve 36, and the pipeline 30 '. , And flows into the accumulator 19 via the slow return valve 18, but the storage pressure of the accumulator 19 rises, and the pressure in the pilot pipe line 31 is almost the same, that is, the head side oil chamber 8a.
When the pressure becomes equal to the pressure of, the switching valve 35 switches from the F position to the E position by the restoring force of the built-in spring. As a result, the pressure oil in the pipe 30 is transferred to the E position oil passage of the switching valve 35 and the pipe 37.
Through the flow rate detecting valve 4 into the oil chamber on the left side of the flow rate detecting valve 4 and moving the piston a to the right, the limit switch 5 operates and the electric wire 33 is closed. Along with this, the power supply passing through the switch 6 excites the make contact 2 via the limit switch 5, so that the make contact 2 is closed and the receiving portion of the on-off valve 17 is energized through the electric wire 29. The on-off valve 17 switches from the A position to the B position, and the line 16
Is connected to the accumulator 19 via the opening / closing valve 17 and the slow return valve 18 and exerts a vibration suppressing effect.However, when the opening / closing valve 17 is switched, the pressure between the oil chamber 8a and the accumulator 19 is changed as described above. However, the working devices 7 do not descend temporarily because they are generally the same.

When the make contact 2 is closed and power is supplied to the electric wire 29, the holding function is given to the make contact 2 regardless of whether the limit switch 5 is opened or closed. Therefore, unless the switch 6 is opened. Since the break contact 3 is opened and the open / close valve 34 is not excited when the power is supplied to the electric wire 29, the open / close valve 34 is switched to the original C position to close the pipe 30. However, the pressure oil discharged from the hydraulic pump 11 flows only into the hydraulic pressure switching valves 12 and 13. further,
When the on-off valve 34 returns to the C position, the flow rate detection valve 4
Since the pressure oil no longer flows in, the pressure oil in the left oil chamber of the flow rate detection valve 4 flows out to the tank 10 through the throttle b built in the piston a and the right oil chamber, so that the piston a gradually increases. The neutral switch is restored, the limit switch 5 is also reset accordingly, and the electric wire 33 is opened.

Next, FIG. 2 is a main part electric / hydraulic system diagram showing another embodiment for supplying pressure oil to the vibration suppressing device 20 according to the present invention. In this figure, instead of providing the opening / closing valve 34 on the branch line 30 in FIG. 1, the hydraulic pump 11 and the hydraulic switching valve 12 are replaced.
The discharge pressure oil of the hydraulic pump 11 is always supplied to the hydraulic pressure switching valve 12 in the middle of the line between and, but when a signal acts on the receiving portion, it switches from the G position to the H position and the hydraulic pump A second on-off valve 38 for communicating the discharge pressure oil 11 to the pipe 30 is provided, and the electric wire 32 from the relay circuit 1 of FIG. 1 is connected to the receiving portion of the on-off valve 38. Others are the same as those in FIG.

In the case of the circuit shown in FIG. 2 above, when the switch 6 is closed in order to give the traveling vibration suppressing function to the working device 7 under a heavy load, the opening / closing valve 38 is switched from the G position to the H position. First, the pressure oil discharged from the hydraulic pump 11 is
It flows into the switching valve 35 through the H position passage 38 and the conduit 30 and supplies pressure oil to the vibration suppressing device 20 as described above, and the accumulated pressure in the accumulator 19 is approximately equal to the pressure in the head side oil chamber 8a. Then, the electric power of the electric wire 32 is cut off, and the on-off valve 38 is turned to G again.
Returning to the position, the entire amount of hydraulic fluid discharged from the hydraulic pump 11 flows into the hydraulic switching valve that operates the working device 7 and the like. At the same time, the on-off valve 17 shown in FIG. 1 is opened, and the conduit 16 is communicated with the vibration suppressing device 20 to realize smooth switching. Therefore, even when the traveling vibration suppressing effect is obtained, it is possible to obtain a stable circuit at the time of switching without specially operating the hydraulic switching valve for operating the working device 7 or the like.

FIG. 3 is an electric / hydraulic system diagram of a main portion of a traveling vibration suppressing / stabilizing circuit provided in a portion where the pipe line 16 and the vibration suppressing device 20 are connected via the opening / closing valve 17. In this figure, a branch line 1 from a line 15a leading to the head side oil chamber 8a of the lift cylinder 8 is shown.
6, the vibration suppressing device 20, the opening / closing valve 17, the electric wire 29 connected to the receiving portion of the opening / closing valve 17, etc. are all the same as those in the embodiment of FIG. Pipe line 16,16 ′
A bypass pipe 40 is provided in the interior of the bypass pipe 40, and a check valve 39 that can flow only in the direction of the pipe 16 is provided in the middle of the bypass pipe 40.

In the circuit configuration shown in this figure, the pressure oil accumulated in the accumulator 19 is always irrespective of the switching position of the opening / closing valve 17 and corresponding to the load variation on the lift cylinder 8.
The pressure does not become higher than the pressure in the head side oil chamber 8a, but on the other hand, the vibration suppressing effect is exerted only when the opening / closing valve 17 is in the B position. Therefore, even if the open / close valve 17 is in the A position, the accumulator 19 is released as the sediment loaded in the working device 7 is discharged and the pressure in the head side oil chamber 8a decreases.
The excess pressure oil inside flows out to the pipeline 16 through the bypass pipeline 40 and the check valve 39 to complete the discharge of the sediment, and immediately after switching the open / close valve 17 to the B position, the accumulator 19
Since the pressures in the head-side oil chamber and the pressure in the head-side oil chamber are approximately the same, the working device 7 can automatically obtain a traveling vibration suppressing and stabilizing circuit that does not rise suddenly.

The circuits shown in FIG. 1, FIG. 2, and FIG. 3 of the above embodiment can be used as a traveling vibration suppressing stabilizing circuit independently in the traveling vibration suppressing device. By further using FIG. 3, FIG. 2 and FIG. 3 in combination, a more effective traveling vibration suppression stabilizing circuit for a wheel-type construction machine can be obtained.

EFFECTS OF THE INVENTION If a stabilizing circuit according to the present invention is provided along with a traveling vibration suppressing circuit of hydraulic means provided in a wheel-type construction machine, it will switch from a hydraulic circuit in a normal working state to a circuit exhibiting a vibration suppressing effect. Automatically, the hydraulic pressure in the oil chamber of the working device supporting hydraulic cylinder and the hydraulic pressure accumulated in the accumulator in the vibration suppression circuit are approximately the same automatically, so that the working device moves up and down during switching. Since it does not oscillate, and the accumulated pressure of the accumulator automatically corresponds to the weight of the work device including the work object,
Safe and stable work is possible without requiring any special operation.

[Brief description of drawings]

FIGS. 1, 2, and 3 are all electric / hydraulic system diagrams showing an embodiment of the present invention. FIG. 1 is a first embodiment, and FIG. 2 is a main part of a second embodiment. FIG. 3 shows a main part of the third embodiment, FIG. 4 is an external side view of a wheel type tractor shovel, and FIG. 5 is an electric part of a conventional traveling vibration suppressing device provided in the wheel type tractor shovel. -It is a hydraulic system diagram. 1 …… Relay circuit 2 …… Make contact 3 …… Break contact 4 …… Flow rate detection valve 5 …… Limit switch 6 …… Switch 17,34,38 …… Opening / closing valve 20 …… Vibration suppressor 35 …… Switching valve

Claims (3)

[Claims] 1. A wheel-type construction machine in which a base end of a boom for a working device is pivotally supported on a wheel body and is supported by a hydraulic cylinder.
Divide the pipeline that leads to the load side oil chamber of the hydraulic cylinder,
In a hydraulic operating circuit connected to a hydraulic vibration suppression device during traveling via a first opening / closing valve that opens an internal oil passage when a signal acts on the receiving portion, the discharge pipe of the hydraulic pump for a working device and the above-mentioned first A second branch line is provided which communicates with the middle of the line from the on-off valve to the vibration suppressing device, and opens the internal oil line only when a signal acts on the receiving section in the middle of the second branch line.
The on-off valve and the branch line from the second on-off valve are normally led to the flow rate detection valve, and when a pressure higher than the pressure in the line communicating with the vibration suppressing device acts on the receiving unit, the valve is connected back and forth. And a switching valve that communicates with the above branch pipe line are arranged in series, and a switch near the driver's seat, a limit switch operated by the flow rate detection valve, and a make contact having a holding function are provided in the receiving portion of the first opening / closing valve. Power is supplied to the receiving portion of the second on-off valve via a switch near the driver's seat and a break contact which opens when the receiving portion of the first on-off valve is energized. A traveling vibration suppressing stabilization circuit for a wheel-type construction machine, in which a pipeline that leads to a load-side oil chamber of a hydraulic cylinder that supports a working device is guided to a receiving portion of the switching valve by a pilot pipeline. 2. A pipeline is normally opened in the middle of a discharge side pipeline of a hydraulic pump for a working device, and when a signal acts on a receiving section, the pipeline is connected to the first opening / closing valve and a vibration suppressing device. A second on-off valve that communicates with a branch line connected to the line between
In the middle of the branch pipe from the second on-off valve, the branch pipe is always guided to the flow rate detection valve, and when a pressure higher than the pressure in the pipe leading to the vibration suppression device acts on the reception unit, A traveling vibration suppressing and stabilizing circuit for a wheeled construction machine according to claim (1), further comprising a switching valve that connects the branch pipes connected to each other. 3. A bypass line connecting the branch lines before and after the first on-off valve provided in the middle of the branch line leading from the load side oil chamber of the hydraulic cylinder to the vibration suppressing device, The above-mentioned claim (1), wherein a check valve is provided in the middle of the bypass pipe, the check valve being able to flow only in the direction of the pipe communicating with the load-side oil chamber of the hydraulic cylinder.
A traveling vibration suppressing and stabilizing circuit for a wheel-type construction machine according to item (2).