JP3115209B2 - Vibration suppression device for vehicle construction machinery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration suppressing device for a vehicle type construction machine having wheels such as a wheel loader.

[0002]

2. Description of the Related Art In general,
In this type of vehicle construction machine, a so-called ride control system is provided in which an accumulator is connected to a hydraulic oil supply / discharge circuit of a hydraulic cylinder for vertically swinging a working device, and the accumulator suppresses body vibration during traveling. There are things.

An example of such a ride control system is shown in a hydraulic circuit diagram of FIG. 5, where 11 is a hydraulic pump, 12 is an oil tank, 13 is a control valve for the hydraulic cylinder 9, and 18 is an accumulator. Reference numeral 27 denotes an open / close switching valve provided in a branch oil passage A extending from the bottom oil chamber 9a of the hydraulic cylinder 9 to the accumulator 18, and reference numeral 22 denotes an operation switch provided in a driver's seat for switching the open / close switching valve 27. At times, the operation switch 22 is operated to open and close the open / close switching valve 27 so that the bottom-side oil chamber 9a and the accumulator 1
8 and the ride control system is configured to work. On the other hand, when an operation such as excavation is performed, the ride control system does not operate if the open / close switching valve 27 is closed. Now, in this apparatus, when the open / close switching valve 27 is switched from the closed state to the open state to operate the ride control system, if the pressure of the accumulator 18 is lower than the pressure of the bottom oil pressure 9b of the hydraulic cylinder 9, the bottom oil chamber 9b
When the oil flows into the accumulator 18 and the hydraulic cylinder 9 contracts, the working device 5 may drop unexpectedly.

Therefore, a small-diameter bypass oil passage (orifice oil passage) for connecting the bottom side oil chamber 9b and the accumulator 18 to the branch oil passage A while bypassing the open / close switching valve 27.
The bottom-side oil chamber 9b and the accumulator 18 are always in the orifice open state by the small-diameter bypass oil path so that a pressure difference between the two does not occur, whereby the open / close switching valve 27 is changed from the closed state to the open state. It is proposed to prevent the working device 5 from unexpectedly lowering when switching.

However, in this case, since the bottom oil chamber 9b of the hydraulic cylinder 9 and the accumulator 18 are always connected with the orifice open, a load acts on the hydraulic cylinder 9 during operations such as excavation and dumping. In this case, oil flows from the hydraulic cylinder 9 to the accumulator 18 side, which causes a new problem that the working force is reduced, and the hydraulic cylinder 9 is contracted and the vehicle body fluctuates.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has been made in order to provide a vibration suppressing device for a vehicle-based construction machine capable of eliminating these disadvantages. The invention described in claim 1 is a vehicle-based construction machine comprising a hydraulic oil accumulator branched and connected to a hydraulic oil supply / discharge circuit of a hydraulic cylinder for vertically swinging a working device. A branch oil passage switching means for switching between an open state, an orifice open state, and a closed state is provided in a branch oil path of an accumulator.
The branch oil passage switching means opens the branch oil passage.
Oil passage switching valve for switching between open and closed states, and branch oil
Second oil that switches the path between open and orifice open
It is characterized in that it is constituted by arranging a path switching valve in series . The invention described in claim 2 is an operation
Supply and discharge of hydraulic oil from a hydraulic cylinder to swing the device up and down
The circuit is connected by branching the vibration suppression accumulator
In the vehicle construction machine, the vibration suppressing accumulator
Open and orifice open and closed
To provide a branch oil passage switching means for switching to the state
The branch oil passage switching means includes an oil passage switching valve for opening and closing the branch oil passage, a bypass oil passage provided around the oil passage switching valve, and a bypass oil passage provided in the bypass oil passage. And a bypass oil path switching valve for switching the path between a closed state and an orifice opened state.
According to the third aspect of the present invention, the working device is vertically swung.
Oil supply and discharge circuit of hydraulic cylinder for vibration suppression
Vehicle-based construction machines with accumulators connected in a branch
The branch oil passage of the vibration suppression accumulator.
Switching between release state, orifice open state and closed state
In providing the branch oil passage switching means , the branch oil passage switching means is constituted by an oil passage switching valve for switching the branch oil passage between an open state, an orifice open state and a closed state. Vibration suppression device in machinery. In these, the detection means for detecting the height of the working device,
The branch oil passage switching means may be connected to switch to the closed state when the detection signal from the detection means is within a preset setting range. Further, in these, the detecting means for detecting the height of the working device is connected to a control unit for outputting a switching control command to the branch oil passage switching means, and the control unit receives a detection signal from the detecting means in advance. When the set range is set, a means for outputting a command for switching the branch oil passage to the closed state to the branch oil passage switching means is provided.

According to the present invention, the hydraulic cylinder and the accumulator are connected with the orifice open even when the vibration suppression system is not operating, and the oil flows to the accumulator during a heavy load operation. It is not to be.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a wheel loader. The wheel loader 1 is mounted on a vehicle body 3 having wheels 2, a driver's seat 4 provided on the upper part of the vehicle body 3, and a front part of the vehicle body 3. The working device 5 includes a lift arm 6 whose base end is supported by a front frame 3a of the vehicle body 3 so as to be vertically swingable, and a distal end of the lift arm 6. The bucket 7 is supported by the section so as to be capable of tilting forward and backward, a bendable link member 8 that connects the middle part of the lift arm 6 and the bucket 7, and the front frame 3 a and the lift arm 6 for vertically swinging the lift arm 6 And a bucket cylinder 10 interposed between the front frame 3a and the link member 8 for tilting the bucket 7 back and forth. The basic configuration of is conventional.

FIG. 2 shows a main part of a pressure oil supply / discharge circuit for the lift cylinder 9. The branch oil passage A provided with the vibration suppressing device of the present invention is connected to the pressure oil supply / discharge circuit. I have. That is, in FIG. 2, 11 is a hydraulic pump, 12 is an oil tank, and 13 is a control valve for the lift cylinder 9. The control valve 13 is a six-port four-position switching valve, and its first port 13
a to the hydraulic pump 11, the second port 13 b to the hydraulic pump 11 via the check valve 14, the third and fourth ports 13
c and 13d are respectively connected to the oil tank 12 and the fifth port 13
e is connected to the rod side (cylinder reduced side) oil chamber 9a of the lift cylinder 9, and the sixth port 13f is connected to the bottom side (cylinder extension side) oil chamber 9b of the lift cylinder 9.

The control valve 13 is
The first port 13a to the fourth port 13d are operated based on the operation of the lift arm operating tool 15 provided in the driver's seat section 4.
And the second, third, fifth, and sixth ports 13b, 13c, 13e, and 13f are closed,
The valve path from the second port 13b to the sixth port 13f and the valve path from the fifth port 13e to the third port 13c are open, and the first and fourth ports are closed cylinder extension positions, and the second port 13b to 5th port 13e
, The sixth port 13f to the third port 1
The valve path leading to 3c is opened and the first and fourth ports are closed, the cylinder contraction position, the valve path from first port 13a to fourth port 13d, and the valve path from second port 13b to fifth port 13e. The valve, the valve path from the sixth port 13f to the third port 13c, and the valve path from the second port 13b to the third port 13c are each switched to the cylinder reduction allowable position.

On the other hand, the branch oil passage A branches from a branch point C in the oil passage B connecting the sixth port 13f of the control valve 13 and the bottom oil chamber 9b of the lift cylinder 9. The branch oil passage A is provided with first and second oil passage switching valves 16 and 17 and accumulators (accumulators such as a bladder type accumulator, a piston type accumulator, a diaphragm type accumulator) 18 in this order from the branch point C side. ing.

The first oil passage switching valve 16 is an electromagnetic two-port two-position switching valve, which is switched by energizing a solenoid 16c based on a switching operation of a microswitch 20 described later. However, the first port 16a is connected to the branch point C, and the second port 16b is connected to the first port 17a of the second oil passage switching valve 17, respectively. When the solenoid 16c is not energized, the first oil passage switching valve 16 closes the first and second ports 16a and 16b to close the branch oil passage A. However, the first oil passage switching valve 16 is energized to the solenoid 16c. Thus, the valve passage connecting the first port 16a and the second port 16b is opened, and the branch oil passage A is opened.

The second oil passage switching valve 17 is an electromagnetic four-port two-position switching valve,
The solenoid 17e is energized based on the ON operation of a vibration suppression (ride control system) operation switch 22 provided in the solenoid valve 17a. The first port 17a is connected to the first oil as described above. Road switching valve 1
6, the second port b is connected to the accumulator 18, and the third port 17c is connected to the oil tank 12. The fourth port 17d is connected to an auxiliary branch oil passage F branched from a branch point E in an oil passage D connecting the fifth port 13e of the control valve 13 and the rod-side oil chamber 9a of the lift cylinder 9. It is connected. When the solenoid 17e is not energized, the second oil passage switching valve 17 opens the branch oil passage A in a state where the valve passage connecting the first port 17a and the second port 17b is throttled. While the orifice is opened, the valve passage connecting the fourth port 17d and the third port 17c is closed, and the auxiliary branch oil passage F is closed.
When the solenoid 17c is energized, the first port 1
A valve path connecting the first port 7b and the second port 17b and a valve path connecting the fourth port 17d and the third port 17c are opened to open the branch oil passage A and the auxiliary branch oil passage F. Is configured.

On the other hand, a portion of the front frame 3a close to the base end of the lift arm 6 is provided with a microswitch 2
0 is attached. Further, a cam body 21 for switching a switch contact of the micro switch 20 is provided at a base end of the lift arm 6. Then, when the height position T of the lift arm 6 is smaller than the preset first set height T ₁ (T <T ₁ ), and is equal to or larger than the preset second set height T ₂ (T ≧ T _2). ), The cam body 21 is separated from the switch lever 20a of the micro switch 20, and the switch contact of the micro switch 20 is open, but the height position of the lift arm 6 is equal to the first set height T. ₁ or more and less than the second set height T ₂ (T ₁ ≦
When T <T ₂ ), the cam body 21 is switched to the switch lever 2
0a is pressed so that the switch contact of the microswitch 20 is switched to the closed side.

When the micro switch 20 is opened, the micro switch 20 is connected to the solenoid 16 c of the first oil passage switching valve 16.
, But is electrically connected to energize the solenoid 16c when the microswitch 20 is closed.

The first and second set heights T ₁ and T ₂ are:
It is configured so that it can be arbitrarily set by adjusting the mounting position of the micro switch 20 and the cam body 21.
In the present embodiment, the height position of the lift arm 6 is equal to or less than the first set height T ₁ when performing an operation such as excavation near the ground using the bucket 7, and the height of the lift arm 6 is reduced to a dump truck by the bucket 7. when Honi becomes second set height T ₂ or more, are more during running of the wheel loader 1 is set to be and the second set height T than ₂ in the first set height T ₁ or more.

In the embodiment of the present invention configured as described above, when the wheel loader 1 travels, the lift arm 6
Wherein the first set but a height above T ₁ at and the height of the second set than the height T ₂ of, in this state, microswitch 20 has the pressing cam 21 is a switch lever 20a, as described above It is closed. As a result, the solenoid 16c of the first oil passage switching valve 16 is in an energized state,
The first oil passage switching valve 16 opens the branch oil passage A. In this state, the operator operates the operation switch 22
Is turned on, the solenoid 17e of the second oil passage switching valve 17 is energized, and the second oil passage switching valve 17 opens the branch oil passage A and the auxiliary branch oil passage F. As a result, the bottom-side oil chamber 9b of the lift cylinder 9 that holds the weight of the working device 5 and generates hydraulic pressure is moved to the accumulator 1
8, a relative motion is generated between the vehicle body 3 and the working device 5 by the spring action of the accumulator 18, and the cushioning action and the lift cylinder 9
The vibration of the vehicle main body 2 is suppressed and reduced by the damping effect of the flow resistance of the pipe flow path leading to, and the ride comfort of the operator during traveling is improved. In this state,
The rod-side oil chamber 9a of the lift cylinder 9 is connected to the oil tank 12, so that oil can enter and exit the rod-side oil chamber 9a.

On the other hand, when the lift arm 6 is located above the first set height T ₁ and below the second set height T ₂ , that is, when the first oil passage switching valve 16 When the operation switch 22 is OFF in the open state, the second oil passage switching valve 17 has the branch oil passage A in the orifice open state. There is no difference in oil pressure between the oil pressure on the bottom oil chamber 9b and the oil pressure on the accumulator 18 side. Thus, as described above, the operator turns on the operation switch 22 to turn on the second oil passage switching valve 17.
Is switched, the oil in the bottom oil chamber 9b does not flow toward the accumulator 18 and the lift cylinder 9 does not contract, and the working device 5 is inadvertently lowered with the ON operation of the operation switch 22. Can be avoided.

On the other hand, when an operation such as excavation near the ground using the bucket 7 or an operation of unloading a dump truck or the like using the bucket 7 is performed, the lift arm 6 is moved to the first set height T. ₁ or less, although the second set height T ₂ or more height, in this state, the cam member 21 as described above is a micro switch 20 are spaced from the switch lever 20a has been opened. As a result, the solenoid 16c of the first oil passage switching valve 16 is de-energized, and the first oil passage switching valve 16 closes the branch oil passage A. Therefore, the pressure oil in the bottom-side oil chamber 9b does not flow toward the accumulator 18 due to the load acting on the lift cylinder 9, and a powerful operation can be performed. It is possible to avoid inconveniences such as wobble.

As described above, according to the embodiment of the present invention, when traveling, the bottom oil chamber 9 of the lift cylinder 9 is operated.
The vibration of the vehicle body 3 can be suppressed and reduced by opening the branch oil passage A that connects the accumulator 18 with the b, and the operation switch 22 is turned on to open the branch oil passage A.
When the operation switch 22 is turned off so that the oil does not flow from the bottom oil chamber 9b to the accumulator 18 side and the lift cylinder 9 is unexpectedly lowered when the second oil passage switching valve 16 is switched. But the second oil passage switching valve 1
Although the orifice 6 is in the open state, the first oil passage switching valve 1 is set based on lowering or raising the lift arm 6 to perform a large load operation.
6 is automatically switched to close the branch oil passage A. As a result, it is possible to prevent the pressure oil in the bottom side oil chamber 9b from flowing to the accumulator 18 side due to the load acting on the lift cylinder 9 during the operation, thereby performing a powerful operation and wobbling the vehicle body 3. Troubles can be avoided.

The present invention is, of course, not limited to the above-described embodiment. The branch oil passage switching means for switching the branch oil passage A between the open state, the orifice open state, and the closed state includes a hydraulic circuit shown in FIG. As in the second embodiment shown in the drawing, a bypass oil passage G is formed to branch off from a branch oil passage A, and a branch oil passage A is formed.
Is provided with a third oil passage switching valve 23 for switching the branch oil passage A between an open state and a closed state based on the operation of the vibration suppression operation switch 22. The bypass oil passage G is provided with a micro switch 20. It can also be configured by providing a bypass oil passage switching valve 24 that switches the bypass oil passage G between a closed state and an orifice opened state based on a switching operation. further,
As in the third embodiment shown in the hydraulic circuit diagram of FIG.
Can be configured using a fourth oil passage switching valve 25 that switches between an open state, an orifice open state, and a closed state,
In each case of the second and third embodiments, the same operation and effect as those of the first embodiment can be obtained. Further, in the first embodiment, the height position of the lift arm 6 is detected by the micro switch 20, and the micro switch 20 and the first all-replacement valve 16 are electrically connected. However, the present invention is not limited to this. For example, as in the third embodiment shown in FIG.
The height position of the lift arm is detected by an angle detection sensor 25 provided on the lift arm.
And the vibration suppressing operation switch 22 is connected to a control unit 26 composed of a microcomputer or the like, and based on a signal input from the angle detection sensor 25 and the operation switch 22, the control unit 26 transmits a signal to the fourth oil passage switching valve 25. Alternatively, a switching command may be output.

[0022]

In summary, since the present invention is constructed as described above, the branch oil passage in which the vibration suppressing accumulator is branched is formed by opening the branch oil passage, opening the orifice, and closing the branch oil passage. That is, there is provided a branch oil passage switching means for switching between. As a result, by opening the branch oil passage during traveling, the hydraulic cylinder and the accumulator are connected to suppress and reduce the vibration of the vehicle body, and by setting the orifice open, the hydraulic cylinder and the accumulator can be connected. Although it is possible to eliminate the difference in oil pressure between them, at the time of work with a large load, the branch oil passage is closed so that the hydraulic oil of the hydraulic cylinder can be prevented from flowing to the accumulator, and powerful work can be done. And the problem that the vehicle body fluctuates can be avoided. Further, when the branch oil passage switching means is connected to a detecting means for detecting the height of the working device, the branch oil passage switching device automatically performs the operation based on changing the height of the working device to perform the work. By switching to the closed state, workability is improved.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a wheel loader.

FIG. 2 is a hydraulic circuit diagram showing the first embodiment.

FIG. 3 is a hydraulic circuit diagram showing a second embodiment.

FIG. 4 is a hydraulic circuit diagram showing a third embodiment.

FIG. 5 is a hydraulic circuit diagram showing a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 wheel loader 5 working device 9 lift cylinder 16 first oil passage switching valve 17 second oil passage switching valve 18 accumulator 20 micro switch 21 cam body 23 third oil passage switching valve 24 bypass oil passage switching valve 25 fourth oil passage switching Valve 26 control unit A branch oil passage G bypass oil passage

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-136431 (JP, A) JP-A 64-42358 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02F 9/22

Claims (5)

(57) [Claims] 1. A vehicular construction machine in which a vibration suppression accumulator is branched and connected to a hydraulic oil supply / discharge circuit of a hydraulic cylinder for vertically swinging a working device, wherein a branch oil passage of the vibration suppression accumulator is provided. When providing the branch oil path switching means for switching between the open state, the orifice open state and the closed state, the branch oil path
First oil passage switching valve that switches the passage between open and closed states
Switch the branch oil passage between the open state and the orifice open state
And a second oil passage switching valve arranged in series . 2. A hydraulic system for vertically swinging a working device.
Accumulator for vibration suppression
In a vehicle-type construction machine having a branch connection
Open orifice in the branch oil passage of the suppression accumulator
Branch oil path switching hand for switching between open and closed state
In providing the step, the branch oil passage switching means is provided in the oil passage switching valve for opening and closing the branch oil passage, a bypass oil passage provided around the oil passage switching valve, and the bypass oil passage. And a detour oil passage switching valve for switching the detour oil passage between a closed state and an orifice opened state. 3. A hydraulic system for vertically swinging a working device.
Accumulator for vibration suppression
In a vehicle-type construction machine having a branch connection
Open orifice in the branch oil passage of the suppression accumulator
Branch oil path switching hand for switching between open and closed state
When the step is provided, the branch oil passage switching means is constituted by an oil passage switching valve for switching the branch oil passage between an open state, an orifice open state, and a closed state, whereby vibration suppression in a vehicle construction machine is characterized. apparatus. 4. The apparatus according to claim 1, wherein the detecting means for detecting the height of the working device is closed with respect to the branch oil passage switching means when a detection signal from the detecting means is within a preset range. A vibration suppression device for a vehicle-based construction machine, wherein the vibration suppression device is connected to be switched to a state. 5. The control device according to claim 1, wherein the detecting means for detecting the height of the working device is connected to a control unit for outputting a switching control command to the branch oil passage switching means. The unit is provided with a unit that outputs a command to switch the branch oil passage to the closed state to the branch oil passage switching unit when the detection signal from the detection unit is within a preset setting range. Vibration suppression device for vehicle construction machinery.