JPH0649643Y2 - Automatic vibration suppressor for wheeled construction machinery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention This invention relates to a wheel-type construction machine in which a working device projects from a vehicle body and is jointed to the working device. Position the
During traveling, due to the action of the hydraulic cylinder, the vehicle body vibrates 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, the working device is provided in a jointed state in which most of the vehicle main body projects forward and rarely rearward, and the entire working device is rotated up and down around a joint. 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, with recent wheel-type construction machinery, in addition to the dramatic improvement in running performance, handling performance, and running safety, diversification of work types has made it possible to carry out 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 or a work device having a large weight ratio including a work object in the entire vehicle weight often travels 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 wheel-type construction machine, a main structure of a wheel-type tractor shovel shown in FIG. 1 will be described. This machine has a plurality of wheels (for example, four wheels) 1
The working device 3 is mounted on the front frame 2a of the vehicle body 2 having the above. The working device 3 includes a front frame 2a.
A boom 4 whose base end is rotatably supported in an articulated manner,
A bucket 5 rotatably supported at the tip of the boom 4,
A cross link 6 and a dump link 7 flexibly connected between an intermediate portion of the boom 4 and one side portion 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 ridden 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 tilted obliquely upward, and then the rear wheel 1 is riding on the convex portion, the machine traveling direction axis line. On the contrary, the front tilts diagonally downward and swings. Such swinging of the machine is not limited to the forward / backward direction, but when any one of the left and right wheels of the wheels 1 and 1 enters the uneven portion of the ground 30 ', the swinging in the left / right direction is perpendicular to the traveling direction. Occurs. Not only is it impossible to avoid the unevenness that causes the above-mentioned swings at the work site, but it is smooth on general public roads, but it has undulations.
The same phenomenon as described above occurs as the traveling speed of the wheeled tractor shovel increases. In the wheel-type construction machine such as the wheel-type tractor shovel illustrated here, as described above, the wheel base is relatively short, the height of the center of gravity is high, and a suspension spring that absorbs the vertical movement of the wheels 1 and 1 is also included. Since the working device 3 is not provided and is firmly fixed to the front frame 2a of the vehicle body 2 by the boom 4 and the lift cylinder 8 while traveling, the working device 3 is not provided. The swing, the amplitude, and the cycle of the swing together with the vehicle body 2 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 further added to the natural vibration of the entire machine, and the amplitude appears as non-damped vibration that becomes larger and larger, 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 in the piston rod of a boom hoist cylinder in a mobile crane, as disclosed in Japanese Patent Laid-Open No. 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, JP-A-60-11930, an arm cylinder, a bucket cylinder, or the like is provided between the boom and arm cylinder of a hydraulic excavator or between the arm and bucket cylinder. It is known that a cushioning cylinder is provided separately from the working hydraulic cylinder.

Problems to be Solved by the Invention As described above, the vibration suppression method has recently come to have a special structure for a hydraulic cylinder that supports a working device, or an auxiliary device that separately absorbs and damps vibrations, or vibrations. Although countermeasures such as providing a suppression 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 working device is ensured during the working by the working 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 Problems The present invention has the following configuration in order to solve the above problems. That is, a. Vehicle of wheeled construction machine equipped with a transmitter that generates an electric signal proportional to the rotational speed of the traveling wheel or its drive system and a speedometer that receives the electrical signal and displays the traveling speed of the vehicle in digital or analog value. An accumulator is provided in the branch line of the hydraulic line on the load side of the hydraulic cylinder that supports the working device that is articulated to the main body via an electromagnetic switching valve and a slow return valve in series. The electromagnetic switching valve normally closes the internal oil passage by the urging force of the built-in spring, and has the function of opening the internal oil passage when an electric signal from the outside acts on the receiving section. ． The output circuit of the speedometer transmitter is branched and led to a relay circuit, and when the speed meter indicates an electric signal that exceeds a predetermined value, the contact operates to close the main electric circuit. Provide a relay, d. A power source is connected to the receiving portion of the electromagnetic switching valve via the relay.

When the work device completes work such as excavation / loading and starts medium-distance movement or long-distance self-propelled, and the traveling speed exceeds a certain value, the output electric signal of the speedometer transmitter increases. , The main electric circuit of the relay is closed, and with this,
The internal oil passage of the electromagnetic switching valve is automatically opened, and the load-side hydraulic pipeline of the hydraulic cylinder that supports the working device communicates with the accumulator through the branch pipeline, the electromagnetic switching valve, and the slow return valve. The device vibrates separately with respect to the vehicle body, the vibration energy is absorbed, and the vibration is damped, so that the vibration suppressing effect of the entire machine is obtained without any special operation. Also, when the traveling speed is reduced or stopped, the output electric signal of the speedometer transmitter decreases, the main electric circuit of the relay opens, the internal oil passage of the electromagnetic switching valve closes, and the working device becomes a hydraulic cylinder. It is firmly supported by the vehicle body.

Embodiment FIG. 1 shows a side view of a wheel type tractor excavator as a representative example of a wheel type construction machine to which the present invention is applied. The main structure 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, 12 is a hydraulic switching valve for a dump cylinder, and 13 is a hydraulic switching valve for a lift cylinder. Pipeline 14
The head side oil chamber 9a and the rod side oil chamber 9b of the dump cylinder 9 are connected via a and 14b, and a lift cylinder hydraulic switching valve
A head-side oil chamber 8a and a rod-side oil chamber 8b of the lift cylinder 8 are connected to 13 via pipe lines 15a and 15b. Further, in the lift cylinder 8, a branch conduit 16 is provided in the middle of the oil chamber on the side where the weight of the working device 3 is loaded, that is, the conduit 15a connected to the head-side oil chamber 8a. A slow return valve 18 including a variable throttle portion 18a and a check valve 18b is connected via an electromagnetic switching valve 17, and an accumulator 19 is connected to the slow return valve 18. In addition,
As the accumulator 19, a prada type accumulator is usually used, and it may be used in various combinations, such as the pressure of the enclosed gas and the number of used gas, singular or plural, depending on the size of the load, the installation space and other factors. A vibration suppressing circuit 20 including an accumulator 19 and a slow return valve 18 is connected between the head side oil chamber 8a of the lift cylinder 8 and the lift cylinder hydraulic pressure switching valve 13 by an external pipe including pipe lines 15a and 16. . Therefore, the accumulator 19 and the like are within a range that does not interfere with the rotation of the boom 4 and the extension and contraction operation of the lift cylinder 8,
It may be installed at any position on the front frame 2a depending on the connection piping method.

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

In addition, in a wheel type construction machine such as a wheel type tractor excavator that is capable of producing a maximum speed above a certain level on a general public road, a speedometer visible from the driver's seat can constantly indicate the running speed state of the vehicle. Although the installation is obligatory, as an example, the drive shaft 31 of FIG. 3 meshes with the drive system of the wheel 1, for example, the final stage drive shaft of the transmission (not shown) and rotates at a constant ratio with the wheel 1. A transmitter 32 driven by is provided, and its output is led to a speedometer 33 by an electric wiring 37 so that the traveling speed corresponding to the rotation speed of the wheel 1 is displayed in a digital or analog value.

Further, in this invention, the output part is connected to the receiving part of the electromagnetic switching valve 17, the input part is provided with the relay 29 connected to the power source 36 via the switch 35, and the relay circuit 39 of the relay 29 is an electrical wiring. 39, the frequency discriminator 34 and the electric wiring 38 are connected to the electric wiring 37, the traveling speed of the vehicle increases, and when the output of the transmitter 32 exceeds a certain value, the relay 29 operates, The main electric circuit of the relay 29 is closed, and the power source 39 is guided to the receiving portion of the electromagnetic switching valve 17 via the switch 35.

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. In this way, the traveling speed of the vehicle during excavation and loading work in a relatively narrow place is about several kilometers per hour, but when the transportation distance of earth and sand becomes long or when the vehicle is forwarded by self-propelled, etc. ,
The traveling speed is increased for the purpose of shortening the required time.

In such work, even when the switch 35 is closed, when the traveling speed is low, the electric signal from the transmitter 32 is small, and the relay 29 is not activated. Since the circuit maintains the open state, the electromagnetic switching valve 17 also stays in the A position. That is, during excavation / loading work, short-distance movement, and traveling on a rough road, the vehicle traveling speed is low, and the branch pipe 16 is closed at the position A of the electromagnetic switching valve 17, so that the head side of the cylinder 8 is closed. The oil chamber 8a and the lift cylinder hydraulic switching valve 13 are directly connected to the pipe line 15a, and the state of the hydraulic circuit supporting the working device is such that the lift cylinder hydraulic switching valve 13 is neutral as in the case of a normal wheel type tractor shovel. When, the front frame of the vehicle body 2
The working device 3 is firmly connected to 2a.

Next, when carrying the medium distance while loading the bucket 5 with earth and sand, or when forwarding the vehicle by self-propelled,
Place the transmission lever (not shown) in the high speed stage to move forward and backward,
As the vehicle speed gradually increased, the transmitter 32
Since the rotation of the electric motor increases and the electric signal also increases, the electric signal finally activates the relay 29 via the frequency discriminator 34 and closes the main electric circuit of the relay 29.
36 is guided to the receiving portion of the electromagnetic switching valve 17 through the switch 35 and the relay 29, the electromagnetic switching valve 17 is switched from the A position to the B position, and the branch pipe line 16 makes the pipe line 15a vibrate suppression circuit 20. To automatically connect.

As a result, the head side oil chamber 8a of the lift cylinder 8 and the pipeline 15
The pressure oil in a can flow into the accumulator 19 through the branch pipe 16, the B position passage of the electromagnetic switching valve 17, and the slow return valve 18.

In this state, the wheel type tractor excavator travels, the vehicle body 2 vibrates in response to the ups and downs of the road surface, and the rapid acceleration and deceleration, so that the working device 3 vibrates, and the boom 4 supporting the working device 3 moves. The head side oil chamber 8a of the lift cylinder 8 supporting the boom 4 in an attempt to rotate in the vertical direction.
Pressure fluctuations occur at. At this time, since the head side oil chamber 8a communicates with the accumulator 19 via the conduit 15a, the branch conduit 16, the electromagnetic switching valve 17, and the slow return valve 18, the pressure oil flows out to the accumulator 19. I will enter.
At this 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, during traveling, the vehicle body 2 side hardly vibrates, the sub-vibration work device 3 side vibrates, and the work device 3 side receives the spring force, that is, the accumulated pressure of the accumulator 19 from the ground 30 and the road surface side at all times. The vibration is suppressed by acting in the direction opposite to the exciting force, and at the same time, the variable throttle portion 18a exerts a vibration damping action, whereby the 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. Also, for example, even when traveling at high speed, when it is required that the vehicle body 2 and the working device 3 are always integrated and have the same movement, the power switch 35 is opened, It goes without saying that the electromagnetic switching valve 17 always holds the position A and the branch pipe line 16 is closed.

FIG. 4 is a diagram showing an electric circuit in the case of a vehicle equipped with a centrifugal mechanical type speedometer according to a second embodiment of the present invention, and hydraulic circuits not shown in FIG. It is the same. In the figure, reference numeral 40 denotes a tachometer cable for extracting rotation from a traveling power system such as a final stage drive shaft of a transmission, and the other end thereof is connected to a centrifugal speedometer 41.

42 is a limit switch, which closes the relay circuit of the relay 43 when the pointer of the speedometer 41 indicates a speed above a certain value, and the power supply 36 when the main electric circuit of the relay 43 is closed.
Excites the electromagnetic switching valve 17 through the switch 35 and the relay 43.

In the second embodiment described above, the operation is similar to that in the first embodiment, and the vehicle speed increases automatically, and when the vehicle body reaches the speed at which the vehicle body vibrates due to the influence of the unevenness of the road surface, the vibration automatically occurs. It switches to the suppression circuit.

Effect of the Invention When the device of the present invention is mounted on a wheel-type construction machine having wheels and a work device supported on a vehicle body so as to be able to move up and down through a lift cylinder, the wheel-type construction machine is working. While traveling at low speed, the working device is held integrally with the vehicle body by the lift cylinder as before, and is supported by the working device via the vibration suppression circuit when traveling at high speed for transportation and forwarding. Since it switches automatically as described above, there is no vibration of the vehicle body even at high speed, the driver only has to concentrate on the operation of the working device or the steering operation, and the ride comfort is good, Less fatigue, safer and more efficient work. Further, when the vibration suppressing circuit is not required, it is sufficient to operate the switch, so that one machine can be used for multiple purposes.

Further, since all the equipment constituting the present invention is a general-purpose product, and the degree of freedom in selecting its mounting location is high, it is easy to add it to an existing machine and is economically advantageous.

BRIEF DESCRIPTION OF THE 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, and FIG. 4 is an electric system diagram of a main part showing a second 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 29,43 …… Relay 32 …… Transmitter 33, 41 …… Speedometer 34 …… Frequency discriminator

Claims (1)

[Scope of utility model registration request] 1. A wheel-type construction machine in which one end of a work device is pivotally supported on a vehicle body, and a hydraulic cylinder supports the own weight and work load of the work device, or a predetermined rotation is performed. A vibration suppressing circuit provided so as to communicate with a branch pipeline of a pipeline communicating with the oil chamber of the hydraulic cylinder on the side where pressure is generated, and an opening / closing unit that opens and closes the branch pipeline when a signal acts on the receiving unit, An automatic vibration suppressing device for a wheel-type construction machine, comprising: a transmitting means for supplying a signal to the receiving portion of the opening / closing means when the traveling speed of the vehicle increases and the vibration of the vehicle body exceeds a predetermined value.