JPH0672447B2 - Automatic vibration suppressor for wheeled construction machinery - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel-type construction machine of a type in which a working device projects from a vehicle body and is jointed to the working device. During positioning and high-speed running, the action of the hydraulic cylinders causes the vehicle body to vibrate up and down, front and back, left and right, and pitching, rolling,
The present invention relates to an automatic vibration suppressing device that automatically suppresses yawing and the like in a damping manner and improves ride comfort and driving operability.

2. Description of the Related Art In a wheel-type construction machine, its working device is provided in a vehicle body, most of which is forward, and rarely protruding rearward, in a jointed state, and the entire working device is rotated up and down around a joint portion,
A hydraulic cylinder or the like is provided between the working device and the vehicle body to hold the fixed position. As a result, a work object is reliably handled by the work device, and a predetermined work posture or running posture is maintained, so that a hydraulic cylinder or the like having a large capacity is adopted. On the other hand, due to the nature of the work, the above-described work device has a conventional structure and is apt to increase in weight, and the center of gravity of the entire vehicle is largely dependent on the position and weight of the work device.

In particular, in recent vehicle-type construction machines, in addition to the dramatic improvement in running performance, handling performance, and running safety, diversification of work types has made it possible to perform short-distance movement with the work target loaded on the work equipment. It is more economical to do so, or to transfer by self-propelled between work sites,
There are many requests.

As a result, a work device having a large ratio of the work device or the work object to the total weight of the vehicle is often mounted while being firmly attached to the vehicle body. In addition, in general, wheel-type construction machines are much smaller than wheel-type construction machines, which are mainly used for running, because of their maneuverability at narrow work sites, and the wheelbase is as small as possible. This is the actual situation that cannot be helped.

For example, as a typical example of a vehicle-type construction machine, the main structure of a wheel-type tractor shovel shown in FIG. 1 will be described. This machine has a vehicle main body 2 including a plurality of (for example, four) wheels 1. The working device 3 is mounted on the front frame 2a. The working device 3 includes a boom 4 whose base end is rotatably supported by the front frame 2a in an articulated manner, a bucket 5 rotatably supported by the tip of the boom 4, and an intermediate part of the boom 4. A cross link 6 and a dump link 7 flexibly connected to one side of the bucket 5.
A lift cylinder 8 provided between the front frame 2a and the boom 4, the front frame 2a and the cross link 6
It is constituted by a dump cylinder 9 and the like provided between and.

When the wheel-type tractor shovel as described above travels at a certain speed or more on a ground 30 'having uneven portions or a road surface having a wavy surface as shown in FIG. 1 is lifted on the convex portion of the ground 30 'and is lifted higher than the rear wheel 1, the forward traveling direction axis of the machine is conversely inclined obliquely upward, and then the rear wheel 1 is riding on the convex portion.
On the contrary, the forward axis of the machine tilts obliquely downward and swings. Such swinging of the machine is not limited to the front-back direction,
When either one of the left and right wheels of the wheels 1 and 1 enters the uneven portion of the ground 30 ', the rocking occurs in the left-right direction at right angles to the traveling direction. Not only is it impossible to avoid the above-mentioned unevenness that causes the rocking at the work site,
Even on public roads it is smooth but has undulations,
The same phenomenon as described above occurs as the traveling speed of the wheeled tractor shovel increases. Here, in the wheel-type construction machine such as the wheel-type tractor illustrated,
As described above, the wheel base is relatively short, the height of the center of gravity is high, and a suspension spring that absorbs vertical vibrations of the wheels 1 and 1 is not provided. 4. Since the work cylinder 3 is firmly fixed to the front frame 2a of the vehicle main body 2 by the lift cylinder 8, the working device 3 is integrated with the vehicle main body 2 in terms of swing, swing and cycle. It will vibrate. Therefore,
When traveling at high speed, the wheels 1, 1 ride on and off the road surface and uneven parts on the ground at a certain interval with respect to the single natural frequency of the entire machine supported by the elastic pneumatic rubber tire. As a result, the vibration is simply added to the natural vibration of the entire machine, and the amplitude appears as a non-damped vibration that increases more and more, and the vibration tends to continue or increase for a long time as long as it is within a certain traveling speed range.

Continuing to run in such a state is not only uncomfortable to ride, but also causes a risk of erroneous operation of driving, and even if it does not reach that level, fatigue of the driver is large.

In recent years, in order to prevent this vibration, the lift cylinder 8 for holding the working device 3 in FIG. 2 in a fixed position is given shock absorbing performance, and the working device 3 having a relatively high weight is provided.
There is one in which the vibration of (1) is supported by the vehicle body 2 so as to be a damped vibration and is performed separately from the vibration of the vehicle body 2, so that the vibration of the entire machine is always a damped vibration.

There are several examples of methods for forcibly generating this damped vibration. The first example is a spring inside a piston rod of a boom hoist cylinder in a mobile crane, as disclosed in JP-A-59-182195. It is known that an (auxiliary spring) and a damper mechanism are provided. In this device, the piston rod of the hoist cylinder is formed hollow, and a large number of members such as auxiliary pistons, metal springs, spring guides, support rings, etc. are built inside the rod and it acts as a holding pressure to support the working device. N ₂ gas must be enclosed.

As a second example, as disclosed in, for example, Japanese Patent Application Laid-Open No. 60-11930, an arm cylinder or a basket is provided between a boom and an arm cylinder of a hydraulic excavator or between an arm and a bucket cylinder. It is known that a cushioning cylinder is provided separately from a working hydraulic cylinder such as a cylinder.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As described above, the vibration suppressing method has recently come to have a special structure for a hydraulic cylinder that supports a working device, or an auxiliary device that individually absorbs and damps vibrations, or a vibration suppressing device. Countermeasures such as providing an auxiliary hydraulic circuit have been proposed,
In the first example, the vibration damping constant is determined by the spring constant for reducing vibration and the property of the orifice, and cannot be easily changed, and it is also very difficult to set the constant. In addition, the structure is complicated and the manufacturing cost is high. In addition, in the second example, the purpose is to prevent the constituent members of the working device tip end from resonating during traveling of the vehicle body and the effect of suppressing the vibration of the entire machine. Is few.

In view of the above, the present invention has a simple structure, is low in cost, and can be easily applied to a conventional machine. Moreover, the hydraulic pressure between the vehicle body and the work device is ensured during the work by the work device. It is an object of the present invention to provide an automatic vibration suppressing device which is held by a cylinder and is switched to a circuit in which the vibration of the entire machine is automatically attenuated during traveling.

Means for Solving the Problems The present invention has the following configuration in order to solve the above problems. That is, a. The branch line of the hydraulic line on the load side of the hydraulic cylinder that supports the work device articulated to the vehicle body of the wheel-type construction machine is connected to the vibration suppression circuit that is connected to the accumulator via the slow return valve. In the hydraulic circuit device that The branch pipe, which is provided in the middle of the branch pipe and normally closes the internal oil passage by the urging force of a built-in spring, but includes an opening / closing valve that opens the internal oil passage when a signal from the outside acts on the receiving portion. Road opening and closing means, c. A signal that acts on the receiving portion of the on-off valve and outputs a signal to open the valve when it is detected that the operation signal of the speed stage selected by the vehicle becomes an operation signal of a predetermined speed stage or more set in advance. Output means, d. Supply means for guiding the signal from the signal output means to the receiving portion of the opening / closing means, and e. A signal stop means is provided which can arbitrarily stop the output of the signal regardless of the magnitude or presence or absence of the operation signal of the speed stage input to the signal output means.

Action Excavation / excavation can be performed with construction equipment such as wheel-type tractor excavators.
When the process such as loading is completed, and then the vehicle is moved for a medium distance or self-propelled for a long distance, leave the signal stop means of this device inoperative and select the traveling speed stage to the high speed side above a predetermined level. When selected, the signal from the signal output means acts on the receiving portion of the on-off valve on the branch pipeline via the supply means, so that the internal oil passage of the valve automatically opens and the load of the hydraulic cylinder supporting the working device is increased. Since the side oil chamber communicates with the vibration suppression open circuit via the opening / closing valve which is the opening / closing means, the working device vibrates separately with respect to the vehicle body, and the vibration energy is absorbed, damped vibration, and eventually, The vibration suppressing effect of the entire machine can be obtained without any special operation for high speed movement. Further, when the traveling speed stage is set to the low speed or the neutral position, the signal from the signal output means is not output. Therefore, the internal oil passage of the on-off valve is automatically closed by the urging force of the spring, and the working device is a hydraulic cylinder. Is firmly supported by the vehicle body.

If the signal stop means is operated, the signal from the signal output means will not be output regardless of the presence or absence of the operation signal of the speed gear means of the vehicle. The working device is firmly supported integrally with the vehicle body.

Example FIG. 1 shows a side view of a wheel type tractor excavator as a typical example of a wheel type construction machine to which the present invention is applied, and the main constitution of this machine is as described above. The hydraulic circuit of the main part of the tractor shovel is as shown in FIG. In this figure, 10 is a tank, 11 is a hydraulic pump for operating a working device in a hydraulic power unit, and 12 is a hydraulic pump.
Is a hydraulic switching valve for the dump cylinder, 13 is a hydraulic switching valve for the lift cylinder, and is connected to the hydraulic switching valve for the dump cylinder 12 via the pipe lines 14a and 14b.
a, the rod-side oil chamber 9b is connected, and the lift-cylinder hydraulic switching valve 13 is connected to the head-side oil chamber 8a and the rod-side oil chamber 8b of the lift cylinder 8 via the pipe lines 15a and 15b. Further, in the lift cylinder 8, a branch pipe line 16 is provided in the middle of a pipe line 15a connected to the oil chamber on the side where the weight of the work device 3 is loaded, that is, the head side oil chamber 8a.
6 through the electromagnetic switching valve 17 to the variable throttle portion 18a and the check valve 18
A slow return valve 18 including b and b is connected, and an accumulator 19 is connected to the slow return valve 18.
A prada-type accumulator is usually used as the accumulator 19, and it may be used in various combinations such as the pressure of the enclosed gas and the number of the gas used, singular or plural depending on the size of the load, the installation space and other factors. Accumulator 19
A vibration suppression circuit 20 including a slow return valve 18 and the head side oil chamber 8a of the lift cylinder 8 and the lift cylinder hydraulic pressure switching valve 13 are connected by an external pipe including pipe lines 15a and 16. Therefore, the accumulator 19 or the like may be installed at any position of the front frame 2a depending on the range that does not hinder the rotation of the boom 4 and the extension / contraction operation of the lift cylinder 8 and the connecting piping method.

Further, 21 is a main relief valve 22, 23, 24 is an overload relief valve of a circuit communicating with the pipelines 14a, 14b, 15a, respectively, and 25, 26, 27, 28 are check valves for preventing cavitation.

Further, 29 is a hydraulic clutch 36, 37, which selects and switches the speed stage of the transmission (not shown) for traveling the vehicle, forward and backward, etc.
38, 39 (hydraulic clutch for forward / reverse selection not shown) for operating clutch control valve 31 and other hydraulic pumps that serve as a hydraulic source, the discharge pressure oil of which is regulated by a relief valve and passes through a conduit 40, It flows into the clutch control valve 31.

The clutch control valve 31 is composed of a regulator valve 32, a clutch cutoff valve 33, a forward / reverse selector valve 34, and a speed stage selector valve 35. Of these, the pressure oil outlet port from the speed stage selector valve 35 is Four are provided independently, and by sliding the position of the spool in four steps, pressure oil is supplied from each port to the hydraulic clutch 36 for the first speed through the conduit 41.
Selectively through the line 42 to the second speed hydraulic clutch 37, through the line 43 to the third speed hydraulic clutch 38, and through the line 44 to the fourth speed hydraulic clutch 39. It can be sent to. Then, pipeline 4 branched from pipeline 43
5, the pipe line 46 branched from the pipe line 44 is connected to the shuttle valve 48, the outlet port of the shuttle valve 48 is connected to the pressure switch 49 by the pipe line 47, and at the same time, the power source 51 is switched to the switch.
50, which is led to the receiving portion of the electromagnetic switching valve 17 via the pressure switch 49.

As shown in the drawing, the electromagnetic switching valve 17 is in the A position due to the urging force of the built-in spring when it is not excited, and shuts off the conduit 16, but when it is excited, it switches to the B position, and the conduit 16 is closed. And the accumulator 19 are communicated with each other via the slow return valve 18.

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

When excavating and loading with a wheeled tractor shovel, the working device 3 is lowered and the bottom surface of the bucket 5 is placed on the ground 30.
When the bucket 5 is fully loaded with earth and sand, the working device 3 is lifted by the lift cylinder 8, and the bucket 5 is adjusted to an angle so that the earth and sand do not flow out, and the forward or backward movement is performed. Move to a predetermined place and discharge the earth and sand. Of course, when the moving distance is relatively long, when there is an obstacle above the moving passage, or when there are many irregularities on the ground, the work device 3 is moved before moving.
To lower position.

The forward speed in the excavating and loading operation as described above is the first forward speed in the machine of the forward three-stage switching system, and the first forward speed or the second speed in the machine of the four-forward switching system. For the reverse speed, use the low speed stage according to the above.

At the time of this kind of work, even if the power switch 50 is closed, the position of the spool of the variable speed stage selector valve 35 is the first position.
As long as the hydraulic clutch 36 or 37 is activated in the first and second speed positions, no pressure is generated in the pipelines 43 and 44, and therefore no pressure is also generated in the pipelines 45, 46 and 47. Therefore, the internal electric circuit of the pressure switch 49 maintains the open circuit state, so the power supply 51
Cannot energize the electromagnetic switching valve 17, the electromagnetic switching valve 17 stays in the A position by the urging force of the spring, and as a result, the head side oil chamber 8a of the lift cylinder 8 and the lift cylinder hydraulic switching valve 13 are separated from each other. , The branch line 16 is directly connected by the line 15a, and the branch line 16 is closed at the position A of the electromagnetic switching valve 17. Therefore, the state of the hydraulic circuit that supports the working device is the same as that in a normal wheel-type tractor shovel. When the switching valve 13 is neutral, the working device 3 is firmly connected to the front frame 2a of the vehicle body 2.

Next, when carrying the medium distance with the soil loaded in the bucket 5 or when forwarding the machine by self-propelled,
For the purpose of shortening the required time, when the spool position of the variable speed stage selector valve 35 is moved to the third speed or the fourth speed and the hydraulic clutch 38 or 39 is operated, the pipeline 43 or 44 and the pipeline branched from them The pressure at 45 or 46 increases.
As a result, the pressure oil on the high-pressure side of either the pipeline 45 or 46 is taken out by the shuttle valve 48 and passed through the pipeline 47 to the pressure switch 49.
To close the internal electric circuit of the pressure switch 49, the power source 51 is guided to the receiving portion of the electromagnetic switching valve 17 via the switch 50 and the pressure switch 49, and the electromagnetic switching valve 17 moves from the A position to the B position. Switch to position. As a result, even if the lift cylinder hydraulic pressure switching valve 13 is in the neutral position, the pressure oil in the head-side oil chamber 8a of the lift cylinder 8 and the pipe line 15a is distributed to the branch pipe line 16, the B position passage of the electromagnetic switching valve 17, It can flow into and out of the accumulator 19 through the slow return valve 18.

In this state, the wheeled tractor excavator runs, the vehicle body 2 vibrates in response to ups and downs of the road surface, rapid acceleration and deceleration,
As a result, the working device 3 vibrates, the boom 4 supporting the working device 3 tries to rotate in the vertical direction, and pressure is applied to the head side oil chamber 8a of the lift cylinder 8 supporting the boom 4. Fluctuation occurs. At this time, the head side oil chamber 8a communicates with the accumulator 19 via the pipe lines 15a, 16 and the electromagnetic switching valve 17 and the slow return valve 18, so that pressure oil can flow into and out of the accumulator 19. Become. At that time, the vibration is suppressed by the damping action of the variable throttle portion 18a of the slow return valve 18, and the riding comfort is also improved.

That is, according to the wheel type shovel loader, the vehicle body 2 side is considered as a main vibration system, and the work device 3 side having a smaller weight (mass) than the vehicle body 2 is considered as a dynamic vibration damper. Therefore, the capacity of the accumulator 19 and the filled gas pressure should be selected so that the natural frequency of the auxiliary vibration system on the side of the work device 3 becomes substantially equal to the natural frequency of the main vibration system on the vehicle body 2 side. As a result, the vehicle main body 2 side hardly vibrates while traveling, and the auxiliary vibration system work device 3
On the working device 3 side, the spring force, that is, the accumulated pressure of the accumulator 19 always acts in the direction opposite to the exciting force received from the ground surface 30 and the road surface side to suppress the vibration, and by the variable throttle portion 18a. Vibration damping effect is demonstrated,
As a result, vibration is greatly and quickly suppressed, and riding comfort is improved.

By selecting and using the vehicle main body 2, the mass of the working device 3, the load state on the working device 3, the road surface condition that causes vibration, the accumulator and the slow return valve that match the usage conditions of the machine, Of course, a larger effect can be expected, but the variable throttle section 18a in the slow return valve 18 is not necessarily limited to a variable type, and a value that is most suitable for the vibration damping effect can be obtained in accordance with the usage condition of the machine. It is also possible to replace the fixed diaphragm part. Further, for example, when it is required that the vehicle body 2 and the working device 3 are always integrated and have the same movement even during high-speed traveling, the power switch 34 is opened. Needless to say, the electromagnetic switching valve 17 always holds the position A, and the branch conduit 16 is closed.

Further, when it is desirable that the automatic vibration suppressing device operates in multiple stages, such as when the traveling speed stage is the second speed, the third speed, and the fourth speed, as shown in FIG.
It is possible by providing 48 'in addition to 48.

FIG. 5 is a hydraulic circuit diagram of an essential part of a method for equalizing the effects of the present invention without using a power source. A hydraulic pilot switching valve 52 is provided in place of the electromagnetic switching valve 17 of FIG. The pilot oil chamber of the hydraulic pilot switching valve 52 and the outlet port of the shuttle valve 48 are connected to each other via a manual switching valve 53.
When it is desired that the automatic vibration suppressor does not operate regardless of the gear position, the manual switching valve 53 automatically vibrates when the manual switching valve 53 is set to the C position and the predetermined speed stage is set. D when it is desired to switch to the suppression circuit
Switch to the position.

EFFECTS OF THE INVENTION When the present invention is applied to a wheel-type construction machine in which a working device is mounted on a vehicle body having wheels so as to be able to move up and down via a lift cylinder, the wheel-type construction machine can be operated at low speed stages. As in the past, the work device is held integrally with the vehicle body by the lift cylinder, and when traveling at high speed stages, the work device is automatically switched to be supported via the vibration suppression circuit, so high-speed traveling, There is little vibration of the car body during forwarding, the driver only has to concentrate on operating the work device or steering operation, and the riding comfort is good, so the driver is less tired, safe and work efficiency is improved. .
Further, when the automatic vibration suppressing circuit is not required, it is possible to easily and quickly change over by operating a switch or a manual switching valve, so that one machine can be applied to multiple purposes.

Further, since all the equipment used in the present invention is a general-purpose product, the degree of freedom in selecting a mounting location is high and it is easy to additionally mount the existing machine, which is economically advantageous.

[Brief description of drawings]

FIG. 1 is a side view showing the configuration of a wheel-type tractor shovel,
FIG. 2 is a side view of the wheeled tractor shovel during traveling, FIG. 3 is an electric / hydraulic system diagram according to the present invention, FIG. 4 and FIG.
The drawing is a hydraulic system diagram of a main part showing another embodiment of the present invention. 3 …… Working device 8 …… Lift cylinder 13 …… Hydraulic switching valve for lift cylinder 17 …… Electromagnetic switching valve 18 …… Slow return valve 20 …… Vibration suppression circuit 31 …… Clutch control valve 49 …… Pressure switch 52… … Hydraulic pilot switching valve 53… Manual switching valve

Claims (1)

[Claims] 1. A wheel-type construction machine in which one end of a working device is pivotally supported by a vehicle body, and a hydraulic cylinder supports the own weight and working load of the working device, or a predetermined rotation is performed to support the working device. A vibration suppressing circuit formed by connecting a branch conduit of a conduit communicating with the oil chamber on the side where the load pressure of the hydraulic cylinder is generated to an accumulator via a slow return valve, and normally provided on the branch conduit. Although the pipe is closed, the opening / closing means for opening the branch pipe when a signal from the outside is supplied to the receiving unit, and the operation signal of the speed stage selected by the vehicle is equal to or higher than a predetermined speed stage set in advance. Signal output means that outputs a signal when it detects that it has become an operation signal, supply means that guides the signal from the signal means to the receiving portion of the opening / closing means, and the signal from the signal output means is stopped arbitrarily. thing Wheel construction machine of the automatic vibration suppression device comprising a signal stopping means possible.