JPH06183243A - Wheel type working vehicle - Google Patents

Abstract

PURPOSE:To moderate the vibration at working without an outrigger, stabilize working posture, and improve working efficiency. CONSTITUTION:A suspension device 27 consisting of a hydraulic cylinder 28, an accumulator 31 and a throttle valve 33, and a stroke sensor 37 for detecting vertical displacement is provided between a chassis 22 and each wheel 25. The detection signal from the sensor 37 is divided into displacements of frequency components higher and lower than a determined frequency by a controller 38. The displacement of the higher component is dumped by the throttle valve 33 of each suspension device 27, and a control valve 35 is controlled on the basis of the deviation obtained by relatively operating the displacement with the lower component with a target value signal followed by calculation to supply and discharge oil liquid to the oil chamber A of the hydraulic cylinder 28 to actively (forcedly) damp the vibration. Thus, a fine vibration at traveling is damped by the throttle valve 33, and a large vibration at turning is damped by the oil liquid supplied to and discharged from the hydraulic cylinder 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel type working vehicle such as a wheel type hydraulic excavator or a wheel type hydraulic crane which can run on a general road, and more particularly to a wheel type working vehicle having an upper swing body.

[0002]

2. Description of the Related Art FIG. 12 shows a wheel type hydraulic excavator as an example of a wheel type working vehicle according to the prior art.

In the figure, 1 is a lower traveling body, 2 is an upper revolving body mounted on the lower traveling body 1 via a revolving device 3 so as to be revolvable, and the upper revolving body 2 has a revolving frame. 4, a driver's cab 5, a machine room 6, a counterweight 7 and the like are provided. Reference numeral 8 indicates a work device provided on the revolving frame 4 adjacent to the operator's cab 5, and the work device 8 is configured to be capable of being lifted and lowered from a boom 8A, an arm 8B, a bucket 8C and the like.

Reference numeral 9 denotes a chassis as a track frame which forms a part of the lower traveling body 1, and a cylindrical round cylinder 10 is provided so as to project upward at the center of the upper surface side of the chassis 9, and the circular cylinder 10 turns. The upper revolving structure 2 is rotatably supported via the device 3.

Reference numeral 11 denotes a front wheel (one of which is shown) provided on both sides of a front axle (not shown) located on the front side of the chassis 9, and reference numeral 12 denotes a rear axle (shown on the rear side of the chassis 9). Rear wheels (only one is shown) provided on both ends of (not shown),
Tires 11A and 12A made of a rubber material having elasticity are mounted on the outer peripheral sides of the wheels 11 and 12, respectively. The wheels 11 and 12 are directly coupled to the chassis 9 via the axles and are also coupled to a traveling hydraulic motor via a speed reducer, a propeller shaft (neither is shown), or the like. There is. The wheels 11 and 12 drive the lower traveling body 1 by being rotationally driven by a hydraulic motor.

Reference numerals 13 and 13 denote outriggers provided on the front and rear ends of the chassis 9, respectively.
The leg portion 13B has a base end side rotatably connected to the left and right end sides of the chassis 9 and a float end 13A.
And an outrigger cylinder (not shown) for rotating each leg 13B. The outriggers 13 are extended by extending the outrigger cylinders and pivoting the legs 13B to float the floats 13A.
The ground is pressed by and the lower traveling body 1 is jacked up.

The wheel type hydraulic excavator according to the prior art has the above-described structure. When excavating work or the like by the working device 8, the operator first operates each leg 13B of each outrigger 13. The undercarriage 1 is jacked up and fixed, and in this state, the excavation work is performed by operating the working device 8 while revolving the upper revolving structure 2. In addition, when the work is completed and the robot moves, the legs 13
B is stored, and in this state, the vehicle travels on a general road or the like and moves.

[0008]

By the way, in the wheel type hydraulic excavator according to the above-mentioned prior art, the undercarriage 1 is jacked up by the respective outriggers 13 to excavate the work in a stable posture. However, the undercarriage 1
When carrying out the work while gradually moving the, the outriggers 13 must be put in and taken out every time the work is carried out.
There is a problem that it takes time to put in and take out each of the outriggers 13 and work efficiency is significantly lowered.

However, when the work is performed without using the respective outriggers 13, the wheels 11 and 12 are
Since the tires 11A and 12A have elasticity, the entire vehicle body vibrates due to the reaction when the work device 8 performs a work operation or when the turning operation of the upper swing body 2 is suddenly stopped. . In particular, when excavating work with the bucket 8C, the excavation reaction force applied to the entire vehicle body suddenly escapes at the moment when the bucket 8C is released from the excavation load, that is, at the moment when the so-called "ground cutting" is performed. There is a problem that the elastic energy of each of the tires 11A and 12A that has been elastically deformed is released and a very large vibration is generated.

Therefore, it is conceivable to apply a suspension device adopted in a vehicle such as an automobile in order to buffer this vibration. However, in the suspension device, static fluctuation of the center of gravity due to the turning motion of the upper swing body 2 and the like is considered. There is a problem in that the upper revolving structure 2 cannot be supported and the upper revolving superstructure 2 is tilted at the time of revolving and the safety is significantly reduced.

The present invention has been made in view of the above-mentioned problems of the prior art, and it is a wheel type which is capable of improving the working efficiency by damping the vibrations at the time of working and stabilizing the working posture without using the outrigger. The purpose is to provide a work vehicle.

[0012]

[Means for Solving the Problems] The structure of a wheel-type work vehicle includes a lower traveling body that is capable of traveling on a road, an upper revolving body that is rotatably provided on the lower traveling body, and an upper revolving body. The lower traveling unit is composed of a truck frame and a pair of left and right wheels provided in front of and behind the truck frame.

In order to solve the above problems,
The features of the configuration adopted by the present invention are: a suspension device provided between each wheel and a track frame and including a hydraulic cylinder; and a hydraulic cylinder of each suspension device in response to a signal from the outside. A valve device for supplying / discharging pressure oil, a displacement detecting unit provided between each wheel and the track frame for detecting a displacement in the height direction between each wheel and the track frame, and each displacement detecting unit. Deviation from a set value and a signal for controlling the supply and discharge of pressure oil to and from the hydraulic cylinders of the suspension devices are output to the valve devices according to the deviation to output the signals to the wheel devices and the track. A control means for controlling the displacement in the height direction with respect to the frame to a predetermined value, and in the control means, among the detection signals from each of the displacement detection means, only a signal having a predetermined frequency or less is supplied to each valve. Go out to the device In the provision of the low-pass filter to.

[0014]

With the above structure, when vibration occurs between each wheel and the track frame, each displacement detecting means causes the displacement (vibration) in the height direction between each wheel and the track frame.
Is detected and output to the control means. As a result, the control means takes out a component (static displacement) of a predetermined frequency or less during the displacement by the low-pass filter, and sends a control signal to each valve device based on the deviation obtained by the comparison calculation with the set value. In response to this control signal, each valve device supplies and discharges pressure oil to the hydraulic cylinder of each suspension device to buffer the displacement (vibration). In addition, a component (dynamic displacement) above a predetermined frequency during displacement is buffered by each suspension device.

[0015]

Embodiments of the present invention will be described below with reference to FIGS. In the embodiment, the same components as those of the conventional technique shown in FIG. 12 described above are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, 21 is a lower traveling body according to the present embodiment, 22 is a chassis as a track frame forming a part of the lower traveling body 21, and a cylindrical round cylinder is provided at the center of the upper surface side of the chassis 22. 23 is projected upward.

Reference numeral 24 denotes a front wheel (only one of which is shown) provided on both sides of a front axle (not shown) located on the front side of the chassis 22, and 25 denotes a rear axle 26 (located on the rear side of the chassis 9). 2 shows rear wheels (only one of which is shown) provided on both ends of the chassis 24. The wheels 24 and 25 are provided so as to be movable up and down with respect to the chassis 22, respectively. Include tires 24A, 2 made of elastic rubber material or the like.
5A is installed.

Reference numerals 27 and 27 denote front axles and rear axles 2 on the front wheels 24 and rear wheels 25, respectively.
6 shows a pair of front and rear suspensions (only one of which is shown) for suspending the chassis 22 via 6, and each suspension 27 includes a hydraulic cylinder 28, an accumulator 31, a throttle valve 33, etc., which will be described later. It is roughly composed.

First, reference numeral 28 denotes a hydraulic cylinder which is provided between the chassis 22 and the rear axle 26 and constitutes the main body of each suspension device 27. The hydraulic cylinder 28 comprises a tube 28A and a piston-rod 28B. An oil chamber A is defined in the tube 28A by the piston-rod 28B. The tube 28A of the hydraulic cylinder 28 is fixed to the lower surface side of the chassis 22, and the piston-rod 28B is fixed to the rear axle 26.

One end of 29 is an oil chamber A of the hydraulic cylinder 28.
Is connected to the oil tank 30 via an electromagnetic proportional pressure control valve 35 described later, and 31 is an accumulator connected via a connection pipe 32 in the middle of the hydraulic pipe 29. The accumulator 31 is formed as a closed container, and the inside thereof is divided into an oil storage chamber B and a gas chamber C by a piston (not shown). And
The accumulator 31 presses the oil liquid in the oil storage chamber B via the piston by the pressure of the pressurized gas filled in the gas chamber C, and the oil liquid is supplied to the hydraulic cylinder via the connection pipe 32 and the hydraulic pipe 29. When the hydraulic cylinder 28 is contracted, the oil liquid in the oil chamber A is added when the hydraulic cylinder 28 is contracted by causing the piston-rod 28B to constantly urge the piston-rod 28B in the extending direction. It is designed to allow the gas to flow into the oil storage chamber B against the pressure of the pressurized gas.

Reference numeral 33 denotes a throttle valve provided in the middle of the connection pipe 32. The throttle valve 33 is provided with oil in the hydraulic cylinder 28 when the hydraulic cylinder 28 expands or contracts due to vibrations during work or traveling. By providing a flow resistance to the oil liquid flowing between the chamber A and the oil storage chamber B of the accumulator 31, a damping effect is exerted to act as a damper, and the vibration at this time is buffered.

Reference numeral 34 denotes a hydraulic pump provided on the other end side of the hydraulic pipe 29. The hydraulic pump 34 holds the oil liquid in the oil tank 30 at a predetermined pressure and the oil chamber A of the hydraulic cylinder 28.
It is to be pumped in.

Reference numeral 35 denotes an electromagnetic proportional pressure control valve (hereinafter referred to as a control valve 35) as a valve device which is located in the middle of the hydraulic pipe 29 and is provided between the accumulator 31 and the hydraulic pump 34. Reference numeral 35 denotes an electromagnetic proportional pressure control valve actuation signal V0 'output from a controller 38 described later.
Is received by the solenoid 35A, and the oil liquid from the hydraulic pump 34 is supplied to the oil chamber A of the hydraulic cylinder 28 or the oil chamber A of the hydraulic chamber A is supplied with the oil liquid from the hydraulic pump 34 in accordance with the voltage value (current value) of the operation signal V0 '. The oil liquid is returned to the oil tank 30 via the return pipe 36.

A stroke sensor 37, which is located near the hydraulic cylinder 28 and is provided between the chassis 22 and the rear axle 26 as displacement detecting means (hereinafter referred to as sensor 3).
7), the sensor 37 is configured as, for example, a potentiometer, and the chassis 22 and the rear axle 26 are
The displacement in the height direction between and is detected, and this detection signal V1 is output to the controller 38.

Reference numeral 38 denotes a controller as a control means composed of a microcomputer or the like. The input side of the controller 38 is connected to the sensor 37,
The output side is connected to the solenoid 35A of the control valve 35. Further, as shown in FIG. 3, a low-pass filter 39 described later is provided in the controller 38, and a set value storage section 40 and a control calculation section 41 described later are stored in a storage area 38A thereof.

First, reference numeral 39 denotes a low-pass filter for cutting off an unnecessary frequency signal in the detection signal V1 output from the sensor 37. The low-pass filter 39 is provided from the sensor 37 as shown in the characteristic diagram of FIG. Of the detection signal V1 is attenuated (cut off) to obtain a detection signal V1 'of a low frequency component.

Reference numeral 40 denotes a set value storage section stored in the storage area 38A. In the set value storage section 40, a reference displacement position in the height direction between the chassis 22 and the wheels 24 and 25 is shown. The target value signal V2 is stored.

Reference numeral 41 denotes a control calculation unit for comparing and calculating the detection signal V1 'from the sensor 37 and the target value signal V2. The control calculation unit 41 is configured as a proportional control calculation unit as shown in FIG. There is. The control calculation section 41 outputs the electromagnetic proportional pressure control valve actuation signal V0 'by the control program shown in FIG. 6 to actuate the control valve 35.

The controller 38 is constructed as described above, and its operation will now be described with reference to FIGS. 6 and 7.

First, when the detection signal V1 shown in FIG. 7 is output from the sensor 37, the low-pass filter 39 cuts off the frequency component (high frequency vibration) having a frequency higher than a predetermined frequency in the detection signal V1. The detection signal V1 'of the low frequency component (vibration of low frequency) is taken out and output to the control calculation unit 41. As a result, the control calculation section 41 reads the above-mentioned detection signal V1 'in step 1 based on the control program shown in FIG. Next, in step 2, the target value signal V2 in the set value storage section 40 shown in FIG. 7 is read out, and in step 3, the target value signal V2 and the detection signal V1 'are compared and calculated as V1'. The deviation V0 from V2 is calculated. Then, in step 4, it is determined whether or not the deviation V0 is "0". When the determination is "YES", the displacement in the height direction between the chassis 22 and the wheels 24 and 25 is a set value (reference value). Since it is the same as the above, the processing from step 1 is repeated. On the other hand, if "NO" is determined in step 4, the process proceeds to step 5 and the deviation V0 is multiplied by the proportional gain to output the electromagnetic proportional pressure control valve actuation signal V0 ', and the control valve 35 is actuated by this actuation signal V0'. It is designed to let you.

The wheel type hydraulic excavator according to the present embodiment has the above-described structure, and since the basic operation thereof is not particularly different from that according to the above-mentioned prior art, each suspension device 27, controller 38, etc. The operation will be described.

When vibration occurs during traveling or during work, and displacement in the height direction occurs between the wheels 24 and 25 and the chassis 22, each sensor 37 detects this displacement and controls the detection signal V1. Output to 38. Then, the controller 38 receiving the detection signal V1 takes out only the detection signal V1 'which is a frequency component below a predetermined frequency among the frequency components in the detection signal V1 by the low-pass filter 39, and blocks the displacement above the predetermined frequency. . As a result, the blocked displacement of the high frequency component, for example, small vibrations (dynamic vibrations) generated during traveling etc. are buffered by the damping effect of the throttle valve 33 of each suspension device 27 separately from the control by the controller 38.

On the other hand, the displacement of the low frequency component which becomes the detection signal V1 'which has passed through the low pass filter 39, for example, a large vibration (static vibration) generated during turning or excavation work, is set value (target value signal V2). The control can be performed by controlling the control valve 35 with the electromagnetic proportional pressure control valve actuation signal V0 'based on the deviation V0 from the oil supply and discharge of the oil liquid into the oil chamber A of the hydraulic cylinder 28 to buffer it.

That is, when the detection signal V1 'indicates a short displacement (when the wheels 24 and 25 approach the chassis 22), the control valve 35 is controlled to control the hydraulic cylinder 28.
Of the oil chamber A is communicated with the hydraulic pump 34 to transfer the oil liquid
By inflowing into the inside, the piston-rod 28B is extended to separate the wheels 24 and 25 from the chassis 22, and conversely, the detection signal V1 'is displaced by a long displacement (the wheels 24 and 25 and the chassis 22). (When is separated from), the control valve 35 is controlled to open the oil chamber A to the oil tank 30 through the return pipe 36 to discharge the oil liquid, and thereby the piston-rod 28B is contracted. By bringing the wheels 24, 25 and the chassis 22 close to each other, the vibration at this time is actively (compulsively) damped to surely prevent the wheel type hydraulic excavator from tilting.

Thus, in the present embodiment, high-frequency vibrations (fine vibrations) during traveling etc. are generated by the throttle valve 3 of each suspension device 27.
In addition to being able to buffer the oil by means of 3, the low-frequency vibration (large vibration, for example, the inclination of the vehicle body) at the time of turning is controlled by controlling the control valve 35 to supply and discharge the oil liquid into the oil chamber A of the hydraulic cylinder 28. Since it is possible to buffer the vibration by excavating reaction force in addition to the static displacement of the center of gravity at the time of turning, it is possible to use each outrigger 13 described in the prior art. In addition, excavation work can be performed in a stable posture, and work efficiency can be significantly improved.

In the above embodiment, the controller 38
Has described that the detection signal V1 output from the stroke sensor 37 is first passed through the low-pass filter 39 to be a detection signal V1 'having a frequency equal to or lower than a predetermined frequency, but the present invention is not limited to this, and is shown in, for example, FIG. As in the first modification,
The controller 38 'may input the deviation V0 "between the detection signal V1 from the stroke sensor 37 and the target value signal V2 of the set value storage section 40 to the low pass filter 39.
Further, as in the second modified example shown in Fig. 9, the controller 38 "may be configured such that the low-pass filter 39 and the control calculation section 41 are replaced. Even in the case of these modified examples, the effects of the above-described embodiment There is no difference.

In the above embodiment, the control calculation unit 41 is described as a proportional control calculation unit as shown in FIG. 5, but instead of this, for example, the hydraulic cylinder 28 to be controlled, the electromagnetic Depending on the response characteristic of the proportional pressure control valve 35, the control calculation unit 41 'may be configured as an integral control calculation unit as in the third modification shown in FIG.
As in the fourth modification shown in FIG. 11, the control calculation unit 41 ″ may be configured as a calculation unit that combines proportional control and integral control.

Further, in the above embodiment, the gas chamber C of the accumulator 31 is filled with the pressurized gas, and the pressurized gas urges the piston-rod 28B of the hydraulic cylinder 28 in the extending direction to act as a gas spring. However, the present invention is not limited to this, and a suspension spring may be provided between the chassis 22 and the front axle / rear axle 26.

[0039]

As described above in detail, according to the present invention, the vibration generated between each wheel and the track frame is converted by the displacement detecting means in the height direction between each wheel and the track frame. Detected and output to the control means, the low-pass filter of the control means extracts a component (static displacement) of a predetermined frequency or less during the displacement, and each valve based on the deviation obtained by comparison calculation with the set value. This displacement (vibration) is buffered by outputting a control signal to the device to supply and discharge pressure oil to the hydraulic cylinders of each suspension device, and at the same time, a component (dynamic displacement) above a predetermined frequency during displacement is Since it is designed to be dampened by the suspension system, it is possible to effectively dampen small vibrations during running, large swings during turning, etc., and stabilize the posture of the car body during working to improve work efficiency and reliability. It is possible to improve.

[Brief description of drawings]

FIG. 1 is a side view of a position similar to FIG. 12 schematically showing a wheel hydraulic excavator according to an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram showing a suspension device and the like in FIG. 1 in an enlarged manner.

3 is a block diagram showing an internal configuration of a controller in FIG.

FIG. 4 is a block diagram showing characteristics of a low pass filter in FIG.

5 is a block diagram showing an internal configuration of a control calculation unit in FIG.

FIG. 6 is a flowchart showing arithmetic processing by a controller.

FIG. 7 is a characteristic diagram showing the correlation of each signal in the controller.

FIG. 8 is a block diagram similar to FIG. 3, showing a controller according to a first modification of the present invention.

FIG. 9 is a block diagram similar to FIG. 3, showing a controller according to a second modification of the present invention.

FIG. 10 is a block diagram similar to FIG. 5, showing an internal configuration of a control calculation unit according to a third modification of the present invention.

FIG. 11 is a block diagram similar to FIG. 5, showing an internal configuration of a control calculation unit according to a fourth modification of the present invention.

FIG. 12 is a side view showing a conventional wheel hydraulic excavator.

[Explanation of symbols]

 2 Upper revolving structure 8 Working device 21 Lower traveling structure 22 Chassis (track frame) 24 Front wheel 25 Rear wheel 27 Suspension device 28 Hydraulic cylinder 35 Electromagnetic proportional pressure control valve (valve device) 37 Stroke sensor (displacement detecting means) 38, 38 ′, 38 ″ controller (control means) 39 low-pass filter V1 detection signal V2 target value signal (set value) V0, V0 ″ deviation V0 ′ electromagnetic proportional pressure control valve actuation signal

Claims (1)

[Claims] 1. A lower traveling body which is capable of traveling on a road, an upper revolving body which is provided on the lower traveling body so as to be rotatable, and a work device which is provided on the upper revolving body so as to be able to descend and descend. A wheel-type working vehicle in which the undercarriage is composed of a track frame and a pair of left and right wheels provided in front of and behind the track frame, and provided between the wheels and the track frame. Between the wheel and the track frame, a suspension device including a hydraulic cylinder, a valve device for supplying and discharging pressure oil to and from the hydraulic cylinder of each suspension device in response to a signal from the outside. Displacement detection means provided respectively for detecting the displacement in the height direction between each wheel and the track frame, and a deviation between a signal from each displacement detection means and a set value is calculated, and each of the deviations is calculated according to the deviation. A control means for outputting a signal for controlling the supply and discharge of pressure oil to and from the hydraulic cylinder of the suspension device to each valve device to control the displacement in the height direction between each wheel and the track frame to a predetermined value, A wheel-type working vehicle characterized in that the control means is provided with a low-pass filter that outputs only a signal having a predetermined frequency or less among the detection signals from the displacement detection means to each valve device.