JPH0513817Y2 - - Google Patents

Description

[Detailed explanation of the invention] Industrial application field This invention uses a working device that protrudes from the vehicle body.
While a wheeled construction machine, which is pivoted to the vehicle body so that it can move up and down and is supported by a hydraulic cylinder equipped with a hydraulic vibration suppression circuit, is in motion, it is necessary to adjust the characteristics suitable for the load state of the work equipment and operating conditions. This invention relates to an adjustment device that can be controlled by the driver's will to provide a vibration suppression circuit.

BACKGROUND ART In wheel-type construction machinery, the working device is protruded from the front part of the vehicle body, and in rare cases at the rear thereof, and a hydraulic cylinder is provided to support the working device with respect to the vehicle body. It is provided between the two and expands and contracts to ensure that the workpiece is handled by the work device and to maintain a predetermined working or running posture. On the other hand, the vehicle itself is a so-called non-shock type vehicle, in which the frame on which the driver's seat, control device, work equipment, power plant, etc. are mounted is directly mounted on an axle with rubber tire wheels. The majority.

In recent years, these wheeled construction machines have seen dramatic improvements in their running performance, maneuverability, and running stability, as well as the diversification of types of work. It is more economical to move a heavy snow plow as a working device, such as a snow plow, and the demand for this is increasing, but this wheel-type construction machine If the vehicle continues to travel at a speed higher than that, the undulations of the road surface will cause undamped oscillations in the vehicle body, such as longitudinal and lateral vibrations, pitching, rolling, and yawing, resulting in large dynamic loads on the vehicle body and the road surface. This not only causes discomfort to the driver, but also causes discomfort and fatigue for the driver, leading to health problems and even erroneous operation.

The occurrence of this undamped vibration is basically strongly influenced by the position of the center of gravity of the entire vehicle, the wheelbase, the proportion of mass that overhangs and protrudes outward from the wheelbase, and the driving conditions. In practical terms, this is caused by a combination of the type, position, and weight of the type of work such as bucket carts and snow plows, the magnitude of the load imposed by the object being worked on, the degree of roughness of the road surface, and the traveling speed. Traditionally, as a method to suppress this vibration, when vibration occurs while driving under certain driving conditions, the driving operation is done by changing the driving speed (mainly by switching to a lower speed), Alternatively, the machine is equipped with hydraulic means in advance, that is, the pressure oil pipe on the load side of the hydraulic cylinder that supports the working device is branched and communicated with the pipe of a vibration suppression circuit consisting of a slow return valve and an accumulator. method is taken.

Among these means, the former method leads to a decrease in work efficiency, and the latter hydraulic method is affected not only by the capacity of the accumulator and the initial gas pressure, but also by the throttling effect of the slow return valve. The vibration absorption energy characteristics of vibration suppression circuits naturally differ, and a vibration suppression circuit that only has certain characteristics will not be able to obtain characteristics suitable for each of the various operating load conditions as described above. will be far from achieving its objectives.

Problems that the invention aims to solve: When using hydraulic means to suppress vibrations of wheeled construction machinery, when there is no load on the working equipment, when the work equipment is loaded with a workpiece, when the working equipment is used as a working tool other than the original In practice, it often happens that a vehicle is driven with special work tools that have different weights and center of gravity positions, but a single accumulator and slow speed vibration suppressing circuit with characteristics suitable for each situation may occur. This could not be achieved with a return valve.

This invention adjusts the characteristics of the vibration suppression circuit according to the driver's will, that is, the load condition of the work equipment.
The present invention aims to provide an adjustment device that provides a suppressing effect.

Means for Solving the Problems In order to solve the above problems, this invention has the following configuration. In other words, the pipe line leading to the load-side oil chamber of the hydraulic cylinder that supports the working equipment is branched, and the throttle part of the slow return valve that constitutes the vibration suppression circuit of the hydraulic means connected to the vibration suppression circuit is connected to the proportional electromagnetic A proportional electromagnetic variable throttle valve is used, and power is supplied to the receiving section of the proportional electromagnetic variable throttle valve via a controller installed near the driver's seat.

Operation By operating the controller to increase or decrease the throttling effect of the proportional electromagnetic variable throttle valve, the vibration energy absorption characteristics of the vibration suppression circuit will change, so vibrations with characteristics suitable for the weight and center of gravity of each work equipment will be created. A suppressive effect can be obtained.

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

1 and 2 are external side views of a wheeled tractor shovel as a typical example of wheeled construction machinery. It shows the driving posture when the vehicle body 2 is installed.
are the same, but the working device 3 when the vehicle is empty when the bucket 5 is installed, when the vehicle is loaded, and when the snow removal plow is installed.
The distance l ₁ between the center of gravity position G and the center of the front wheel 1,
l ₂ , l ₃ and their weights are different.

This wheeled tractor shovel has a working device 3 mounted on a front frame 2a of a vehicle main body 2, which is mounted in a non-shocked manner on the axles of a plurality of wheels 1 using rubber tires. The working device 3 includes a boom 4 whose base end is rotatably supported on a front frame 2a, and a work tool such as a bucket 5 or a snow plow 6 rotatably supported at the tip of the boom 4. , a lift cylinder 8 provided between the front frame 2a and the boom 4, and a dump cylinder 9 provided via a link device between the front frame 2a and the power tool. .

FIG. 3 is a hydraulic system diagram of this wheeled tractor shovel, but it is also an electrical system diagram according to this invention. In this figure, 10 is a tank,
11 is a main pump for operating the working device in the hydraulic power unit, 12 is a hydraulic switching valve for the dump cylinder, and 13 is a hydraulic switching valve for the lift cylinder.
A pipe line 14a is connected to the hydraulic switching valve 12 for the dump cylinder.
The head side oil chamber 9a and the rod side oil chamber 9b of the dump cylinder 9 are connected through the pipe 14b. A side oil chamber 8b is connected thereto. Further, a branch pipe 16 is provided in the middle of the pipe 15a connected to the oil chamber on the side of the lift cylinder 8 where the weight of the working device 3 is loaded, that is, the head side oil chamber 8a. , an electromagnetic on-off valve 17 that normally closes the internal oil passage (position A in the diagram) with the biasing force of a spring, and opens the circuit (position B in the diagram) when an electric signal is input to the receiver. A slow return valve 18 consisting of a proportional electromagnetic variable throttle valve 18a and a check valve 18b is connected through the slow return valve 18, and an accumulator 19 is further connected to the slow return valve 18.

Note that the accumulator 19 is usually a Prada type accumulator, and may be used in various combinations depending on the load size, installation space, and other factors, such as capacity, intended gas pressure, and number of units used. . Also, the accumulator 19
A vibration suppression circuit 20 consisting of a and a slow return valve 18 is connected between the head side oil chamber 8a and the lift cylinder hydraulic switching valve 13 by external piping including pipes 15a and 16. Therefore, the above-mentioned accumulator 19 and the like may be installed at any position on the front frame 2a within a range that does not interfere with the rotation of the boom 4 and the expansion and contraction operations of the lift cylinder 8, and by using a connecting piping method.

Also, 21 is the main relief valve, 22, 2
3 and 24 are conduits 14a, 14b, and 15a, respectively.
an overload relief valve for a circuit communicating with the 2
5, 26, 27, and 28 are check valves for preventing cavitation.

Further, the proportional electromagnetic variable throttle valve 18a, which is the throttle section of the slow return valve 18, increases or decreases its throttle effect depending on the magnitude of an external electric signal, and its receiving section C has a plurality of adjustment stages. The wire 3 is connected through a preset resistor 7 that can be
A power supply 30 is connected through 2 and 33. A switch 29 connects and disconnects the power source 30 to the receiving section of the electromagnetic on-off valve 17 via an electric wire 31 branched from an electric wire 32.

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

When carrying out excavation or loading work with a wheeled tractor shovel, the vehicle speed is very low or the vehicle is stationary, and it is not affected by the undulations of the road surface at all; rather, the working device 3 is The switch 29 is left open since it must maintain a secure relative position with the main body 2. At this time,
The on-off valve 17 is in the A position, and the head side oil chamber 8a of the lift cylinder 8 is connected only to the lift cylinder hydraulic switching valve 13 through the pipe 15a, so the hydraulic circuit of a conventional wheeled tractor shovel is The working device 3 is securely held in the vehicle body 2 as it is.

Next, the machine starts moving to transport the excavated soil and transport it by itself. At this time, when the switch 29 is closed, the power supply 30 passes through the switch 29 and the electric wire 31 and acts on the receiving part of the on-off valve 17. Since the on-off valve 17 is switched from the A position to the B position to open the internal oil passage, the pipe line 15a is communicated with the pipe line of the vibration suppression circuit 20 via the branch pipe line 16 and the B position passage of the on-off valve 17. However, the working device 3 is supported by a lift cylinder 8 that is also provided with a vibration suppression circuit 20, and vibrations of the vehicle body are suppressed. However, as described above, unless the vibration suppression circuit 20 has characteristics commensurate with the weight and center of gravity position of the working device 3, appropriate vibration energy absorption will not be achieved and its effectiveness cannot be expected.

Therefore, on the preset resistor 7 placed near the driver's seat, the conditions of the working device 3 obtained through pre-calculation and experiment, such as when the bucket 5 is attached, when the vehicle is empty, when the vehicle is loaded, or when the snow removal plow 6 is Weight when installed and distance from center of front wheel axis to center of gravity G
The electric signal generation positions are set in multiple stages to provide a throttle effect suitable for each of l ₁ , l ₂ , and l ₃ , and before the start of travel, the preset resistor is set at a stage that matches the conditions of the working device 3 at that time. Select 7 and wire 3
3 to the proportional electromagnetic variable throttle valve 1
8a.

In this way, vibrations caused when a wheeled construction machine similar to a wheeled tractor shovel travels on an uneven road surface at a certain speed or higher are suppressed by a vibration suppression circuit that has a preset throttling effect. can do.

Note that the preset resistor 7 in the above embodiment
When the changing conditions of the working device 3 are limited, the operation can be performed simply by setting the required values in multiple stages in advance and selecting and adjusting the preset resistor 7 to the stage that meets the conditions. However, there are many types of work tools that should be installed as the work equipment 3, or there are various variations in the loading weight of the work object,
When the setting value of the aperture effect is infinite, it is of course possible to use a controller such as a continuously variable resistor in place of the preset resistor 7.

Effects of the invention This invention uses a proportional electromagnetic variable throttle valve in the throttle part of the slow return valve that constitutes the vibration suppression circuit of wheeled construction machinery, and allows easy adjustment by adjusting the controller located near the driver's seat. It is now possible to change the aperture effect. Therefore,
Since you can freely realize various vibration suppression characteristics,
Even if the machine is operated by changing various working devices, the vibration suppression effect most suitable for the conditions and operating conditions of each working device can be achieved by using a simple device and operation.

[Brief explanation of the drawing]

Figure 1 is an external side view of a wheeled tractor shovel equipped with a bucket, Figure 2 is an external side view of a wheeled tractor shovel equipped with a snow removal plow, and Figure 3 is an external side view of a wheeled tractor shovel equipped with a snow removal plow.
The figure is an electric/hydraulic circuit diagram of a wheeled tractor shovel equipped with the device of the present invention. 3... Working device, 18... Slow return valve,
5... Bucket, 18a... Proportional electromagnetic variable throttle valve, 6... Snow removal plow, 7... Preset resistor, 19... Accumulator, 17... Open/close valve,
20... Vibration suppression circuit.

Claims (1)

[Scope of utility model registration request] In wheel-type construction machinery, in which the base end of the working equipment is pivotally supported on the vehicle body, and the hydraulic cylinder supports the working equipment's own weight and work load, and performs predetermined rotational movements, the oil on the load side of the hydraulic cylinder is A hydraulic vibration suppression circuit configured by connecting a pipe line leading to the chamber to an accumulator via a slow return valve consisting of a throttle valve and a check valve, a proportional electromagnetic variable throttle valve as the throttle valve, and a proportional electromagnetic variable throttle valve as the throttle valve. A vibration suppression circuit adjustment device that supplies an electrical signal to the receiving section of the variable throttle valve and consists of a variable resistor placed near the driver's seat.