JPH07180176A - Blade control method of grader and blade controller - Google Patents

Abstract

PURPOSE:To accurately level a ground surface, by vertically swinging and controlling a blade to get the same height displacement with that of an imaginary blade provided at the almost center part of the longitudinal direction of the front and rear wheels when a behicle body travels a rugged face of a road. CONSTITUTION:An arm 23 is supported by an oscillating cylinder 24 to vertically and freely swing at the middle part of the front wheels 7 and the rear wheels 8 of the horizontal member fitting respective wheels. An auxiliary blade 25 attached at the front end of arm 23 is vertically moved by extending or contracting the oscillating cylinder 24. An inclinometer 26 for the longitudinal direction of behicle body is attached to the body. A lift potentiometer 27 detecting the rotary angle of the pin 15 supporting the blade support arm 14 is attached to the pivotal part of the blade support arm 14 to detect the angle of the blade 18 against the horizontal line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a vehicle body having front wheels and rear wheels mounted on a vehicle body, and a blade projecting forward from the vehicle body and vertically swingably mounted on the vehicle body. The present invention relates to a blade control method and a blade control device for controlling blades of a ground leveling vehicle used for floor and roadbed finishing work.

[0002]

2. Description of the Related Art As a ground leveling vehicle, a motor having a long vehicle body with front wheels and rear wheels attached to the front wheel, and blades mounted vertically between a front wheel and a rear wheel of the vehicle body by a lift cylinder. Grader. As disclosed in JP-A-5-8622, there is known a tire dozer or the like in which a blade is attached to a vehicle body provided with front wheels and rear wheels so as to project forward and swing up and down, and a lift cylinder is connected across the blade and the vehicle body. ing.

[0003]

In the former motor grader, the blade a has a front wheel b and a rear wheel c as shown in FIG.
Since the front wheel b / rear wheel c rides on the convex portion d of the ground or falls into the concave portion of the ground, the vertical height change H ₁ of the blade a is the front wheel b / rear wheel c. Is half the vertical height change H of the
By this, it can be reduced gradually and the ground can be leveled.

However, in the above-mentioned motor grader, since the blades are located at the lower part of the vehicle body, it is necessary to make the front-rear intermediate portion of the vehicle body higher than the front and rear wheels, and to increase the distance between the front and rear wheels, that is, the wheel base. Since the vehicle body is long and the vehicle height is high, the entire ground leveling vehicle is large.

In the latter tire dozer, the blade projects forward from the vehicle body, so that the vehicle body can be lowered, and the wheel base can be shortened to downsize the ground leveling vehicle.

However, since the blades of the tire dozer protrude forward of the vehicle body, the blades are larger than the height changes of the front and rear wheels when the front and rear wheels ride on the convex portions of the ground or when they fall into the concave portions. It is difficult to level the ground because the height changes and the uneven portion of the ground increases sequentially by the blade.

Further, in the tire dozer, the blade height control method and control device for correcting and controlling the blade height are used to keep the height of the blade constant. Since the blade is large, the correction height of the blade is large, and the correction height control cannot follow the change in the height of the blade, so that the ground cannot be leveled in some cases.

Therefore, an object of the present invention is to provide a blade control method and a blade control device for a ground leveling vehicle which can solve the above-mentioned problems.

[0009]

A vehicle body having a front wheel 7 and a rear wheel 8 mounted on a vehicle body 6, and a grounded vehicle including a blade 18 that is vertically swingable on the vehicle body 6 and protrudes forward from the vehicle body 6. When the vehicle body 6 travels on an uneven portion of the ground, the blade 18 has the same height displacement as the height displacement of a virtual blade provided substantially in the center of the front wheel 7 and the rear wheel 8 in the front-rear direction. A method for controlling blades of a ground leveling vehicle, which comprises performing vertical swing control so that In a ground leveling vehicle having a vehicle body having front wheels 7 and rear wheels 8 attached to a vehicle body 6, and a blade 18 that is vertically swingable on the vehicle body 6 and protrudes forward from the vehicle body 6, the vehicle body 6 is an uneven portion of the ground. A blade for vertically swinging the blade 18 so that the blade 18 has the same height displacement as the height displacement of a virtual blade provided substantially at the center in the front-rear direction of the front wheel 7 and the rear wheel 8 when traveling. A blade control device for a ground leveling vehicle, comprising a control mechanism.

[0010]

[Operation] Since the height displacement of the blade 18 when the vehicle body 6 travels on the uneven portion is the same as the height displacement of the virtual blades provided substantially at the center of the front wheel 7 and the rear wheel 8 in the front-rear direction, Since the height displacement of the blade 18 is smaller than the height displacement of the front wheels 7 and the rear wheels 8 due to the forward lean and the rear lean of the vehicle body 6, the distance between the front wheels 7 and the rear wheels 8 is short. The ground can be leveled with the same accuracy as.

[0011]

[Examples] As shown in FIGS. 2, 3, and 4, the front-rear intermediate portions of the wheel mounting cross members 2 are connected to the left and right sides of the vehicle body 1 by the support mechanism 3 so as to be vertically swingable. A longitudinal intermediate portion of an equalizer bar 4 is supported on the vehicle body 1 so as to be vertically swingable, and a rod 5 is formed by a ball joint or the like across both longitudinal end portions of the equalizer bar 4 and left and right wheel mounting cross members 2. And the front wheel 7 and the front wheel 8 are respectively attached to the front and rear ends of each wheel mounting cross member 2 to form a vehicle body.

As shown in FIG. 5, the support mechanism 3 includes a support shaft 9 provided in the vehicle body 1, a support hole 10 provided in the wheel mounting cross member 2, and a support shaft 9 between the support shaft 9 and the support hole 10. It comprises a bearing 11 provided, and the wheel mounting cross member 2 is vertically swingable around a support shaft 9. A front running motor 12 and a rear running motor 13 are mounted near the front and rear ends of the wheel mounting cross member 2, respectively. There is.

A rear end of a U-shaped blade supporting arm 14 is rotatably supported by a pin 15 at substantially central portions of the front wheel 7 and the rear wheel 8 of the vehicle body 1 in the front-rear direction, preferably at the central portions, A lift cylinder 17 is pivotally connected between a bracket 16 provided at an intermediate portion of the blade support arm 14 and the vehicle body 1, and a lower rear portion of the blade 18 is connected to a front end portion of the blade support arm 14 by a ball joint 19. By connecting a pair of left and right angle cylinders 20 between the bracket 16 and the upper portion of the rear surface of the blade 18 and extending and contracting the lift cylinder 17, the blade support arm 14 swings up and down and the blade 18 moves up and down. The blade 18 is angled by extending and contracting the left and right angle cylinders 20 and the tilt cylinder 21 is extended. When condensation tilted blade 18 to the left and right (tilt), the pitching cylinder 22 Shin contraction to the blade 18 are so tilted (pitching) back and forth.

As shown in FIG. 2, each wheel mounting cross member 2
An arm 23 is vertically swingably supported by a swing cylinder 24 at an intermediate portion between the front wheel 7 and the rear wheel 8, and an auxiliary blade 25 is attached to a tip end of the arm 23 to extend and retract the swing cylinder 24. As a result, the auxiliary blade 25 swings up and down.

As shown in FIG. 2, a vehicle body front-back inclinometer 26 is attached to the vehicle body 1, and a means for detecting an angle formed by the blade support arm 14 with the horizontal direction of the blade 18, for example, a blade. Lift potentiometer 27 that detects the rotation angle of the pin 15 that supports the support arm 14.
Is installed. The error signal of the acceleration component may be superimposed on the angle output signal of the vehicle body front and rear inclinometer 26 when the traveling speed at the time of work changes. You may make it obtain | require a vehicle body front-back inclination angle. An angle potentiometer 29 for detecting a rotation angle around a vertical axis of a ball joint 28 connecting the angle cylinder 20 and the blade 18 is attached to the blade 18, and a pitching angle detection means, for example, a blade support arm. A pitching potentiometer 30 for detecting a rotation angle around a horizontal axis of a ball joint 19 connecting the blade 14 and the blade 18 is attached.
8, a tilt angle detecting means, for example, a left and right inclinometer 31 and a height detecting means, for example, an ultrasonic sensor 32 are attached.

FIG. 6 is a hydraulic circuit diagram showing the lift cylinder 17, the angle cylinder 20, and the tilt cylinder 2.
1, the pressure oil discharged from the hydraulic pump 40 is fed to the pitching cylinder 22 and the swing cylinder 24 by the lift solenoid proportional control valve 41,
Angle proportional solenoid control valve 42, tilt proportional solenoid control valve 4
3, the pitching electromagnetic proportional control valve 44 and the swing electromagnetic proportional control valve 45 respectively supply and control, and these electromagnetic proportional control valves are switched and controlled so as to have an opening area proportional to the energization amount from the controller 46.

FIG. 7 is an explanatory view of the control device. The electric lever 47, the changeover switch 48, the vehicle body front-rear inclinometer 26, the vehicle body front-rear angular accelerometer 26a, the left-right inclinometer 31, the lift potentiometer 27, the angle potentiometer. 29,
Pitching potentiometer 30, ultrasonic sensor 32,
A display panel 49 is connected to each controller 46, the electric lever 47 can be operated in an arbitrary direction, outputs a signal in the operation direction and an electric signal proportional to an operation stroke, and includes a button switch 50.
An automatic signal is input from the automatic button 51.

Next, the output signal according to the operating direction of the electric lever 47 will be described. Standard time (changeover switch 48 OFF, button switch 50 O
FF) As shown in FIG. 8A, a lift cylinder contraction signal (blade up) is output when operated in the back and forth direction X (a), and a lift cylinder extension signal (blade down) is output when operated in the front (b). Then, a tilt cylinder contraction signal (lower left tilt) is output when operated to the left (c) in the left-right direction Y, and a tilt cylinder extension signal (lower right tilt) is output when operated to the right (d).

When the button switch 50 is ON, as shown in FIG. 8B, when the button switch 50 is operated to the rear (a) in the front-rear direction X, the pitch cylinder contraction signal (blade rearward tilt),
When operated to the front (b), pitch cylinder extension signal (blade forward tilt), to the left (c) in the left-right direction Y, left angle cylinder extension, right angle cylinder contraction signal (blade left front), right (d). When operated, it outputs a right angle cylinder expansion signal and a left angle cylinder contraction signal (the blade front right).

When the changeover switch 48 is ON and the button switch 50 is OFF. The left / right swing cylinder contraction signal (left / right auxiliary blade 25 is raised) when operated in the back (a) in the front-rear direction X, and the left / right swing cylinder extension signal (lower left / right auxiliary blade 25) when operated in the front (b), diagonally left When operated rearward (e), left swing cylinder contraction signal (left auxiliary blade 24 raised), diagonally right rear (f) operated right swing cylinder contraction signal (right auxiliary blade 24 raised), diagonally left front (g) ) To the left swing cylinder extension signal (left auxiliary blade 24
Down), and when operated diagonally to the front right (h), a right swing cylinder extension signal (down the right auxiliary blade 24) is output.

Next, the operation by manual operation will be described. When the automatic signal is not input from the automatic lead 51, the electric lever 47 is operated as shown in FIG.
8. By turning on and off the button switch 50, the amount of electricity proportional to the operation stroke is output to each electromagnetic proportional control valve to control the opening area, thereby raising the blade 18.
It descends, changes the angle angle, changes the tilt angle, changes the pitching angle, and raises and lowers the auxiliary blade 24.

Next, the automatic control will be described. Figure 9
As shown in (a), the blade 18 is brought into contact with the ground A and an automatic signal is input to the controller 46 from the automatic button 51.
As a result, the output signal of the lift potentiometer 27 and the output signal of the vehicle body inclinometer 26 are input to the controller 46, and the controller 46 calculates the angle of the blade support arm 14 with respect to the horizontal and stores it as a target value.

That is, since the angle of the blade support arm 14 with respect to the vehicle body 1 is known from the output signal of the lift potentiometer 27, the angle of the blade support arm 14 with respect to the horizontal is calculated from the angle and the vehicle body front-back angle.

In this state, as shown in FIG. 9B, the front wheels 7
When the vehicle falls into the concave portion B, the vehicle body 1 leans forward and the blade 18 bites into the ground A, but the output signal of the vehicle body front and rear inclinometer 26 changes, and this output signal and the output signal of the lift potentiometer 27 are used for calculation. Since the angle of the blade support arm 14 with respect to the horizontal is different from the target value, the controller 46 calculates a blade lift correction amount based on this, and the controller 46 outputs a lift signal to the lift solenoid proportional control valve 41 to contract the lift cylinder 17. Then, the blade support arm 14 is swung upward.

As a result, the lift potentiometer 27
Of the lift solenoid proportional control valve 41 when the angle with respect to the horizontal of the blade support arm 14 calculated by the controller 46 approaches the target value and coincides with the target value.
Is set to the neutral position, the blade support arm 14 assumes the initially set posture as shown by the phantom line in FIG. 8B.

The blade 18 when the vehicle body 1 leans forward
The height change of the front wheel 7 depends on the pivot point of the blade support arm 14.
Since it is almost in the center of the rear wheel 8, the change in height of the vehicle body 1 is about half, which is small, and since the change in height at the pivot point is not related to the vertical correction amount of the blade 18, the vertical correction amount of the blade 18 is Small enough to follow the forward lean of the vehicle body 1. In other words, the blade 18 is controlled so as to have the same height displacement as the height displacement of the virtual blade C provided substantially in the center of the front wheel 7 and the rear wheel 8 in the front-rear direction, so that the blade 18 is as if the front wheel 7 and the rear wheel. It is controlled so as to be provided approximately in the center in the front-rear direction with respect to 8, so that the ground can be leveled with high accuracy as in the motor grader.

Further, as shown in FIG. 9 (c), when the front wheel 7 rides on the convex portion C and the vehicle body 1 leans backward, the blade supporting arm 14 is set to the target value in the same manner as described above. To control. At this time, the controller 46 outputs a lowering signal to the lift proportional control valve 41 to extend the lift cylinder 17.

During the above operation, the front wheel 7 and the rear wheel 8 swing up and down with respect to the vehicle body 1 together with the vehicle body cross member 2, so that the vertical height of the vehicle body 1, that is, the height of the blade 18 changes. Becomes extremely small, and the ground behind the front wheel 7 is cut flat by the auxiliary blade 25, so that the rear wheel 8 travels on a flat surface and the height of the blade 18 due to the rear wheel 8 running on the uneven portion. Change is significantly smaller.

In the above embodiment, the blade support arm 14
The blade 18
You may control by the height from the ground A of. That is, as shown in FIG. 9A, the pin 15 (center of the front wheel 7 and the rear wheel 8 of the vehicle body 1 in the front-rear direction) that supports the blade support arm 14 when the blade 18 is grounded from the ground A The vertical height H is calculated from the vehicle body front-back tilt angle of the vehicle body front-back tilt meter 26, and the blade support arm 14 at this time is calculated.
The angle with respect to the horizontal is calculated as described above.

When the front wheel 7 falls into the recess B as shown in FIG. 9B, the blade support arm 14 is operated in the same manner as described above.
The height H ₁ of the pin 15 from the ground A is calculated to calculate the height displacement (H−H ₁ ) of the pin 15 at that time. The controller 46 stores in advance the vertical movement amount of the blade 18 when the angle of the blade support arm 14 with respect to the horizontal changes by 1 according to the length L of the blade support arm 14, and the ground of the pin 15 of the blade support arm 14 is stored in advance. The angle change amount with respect to the horizontal direction of the blade support arm 14 for raising the blade 18 by the height displacement (H−H ₁ ) from A is calculated, and the lift cylinder 17 is contracted to move the blade support arm 14 upward. The lift cylinder 17 is stopped when the angle with respect to the horizontal when moving coincides with the calculated angle change amount.

As a result, the blade 18 changes its height by the height displacement of the pin 15 of the blade support arm 14, so that the blade 18 is provided virtually at the center between the front wheel 7 and the rear wheel 8 of the vehicle body 1 in the front-rear direction. The height displacement is the same as the height displacement of the blade C.

Next, another operation will be described. Operation when the pitching angle of the blade 18 is changed depending on the magnitude of the excavation load. From the state shown by the solid line in FIG.
When the blade 18 is tilted backward as indicated by an imaginary line, the blade tip portion 18a of the blade 18 rises. Therefore, the tilting angle of the blade 18 is detected by the pitching potentiometer 30 and is input to the controller 46, and based on the value, The lowering correction amount is calculated and a lowering signal is output to the lift solenoid proportional control valve 41 to extend the lift cylinder 17 to lower the blade 18, and when the lowering amount matches the calculated blade lowering correction amount, the lift solenoid proportional control valve 41 Is made neutral, whereby the cutting edge portion 18a of the blade 18 returns to its original position as shown in FIG. 9 (b).

When the blade 18 is tilted forward as shown by the phantom line from the state shown by the solid line in FIG. 10 (c), the cutting edge portion 18a of the blade 18 is lowered, so that the blade 18 is raised in the same manner as described above. As shown in FIG. 10D, the blade tip portion 18a of the blade 18 is set to the original position. At this time, a lift signal is input to the lift solenoid proportional control valve 41, and the lift cylinder 17 contracts.

Next, the operation for controlling the blade height to a constant level using the ultrasonic sensor 32 will be described. A signal line corresponding to the distance between the ultrasonic sensor 32 and the reference line is detected by the ultrasonic sensor 32 detecting the reference line such that the reference line such as a water thread is stretched parallel to the surface of the ground to be leveled, for example, horizontally. To be output. In the above-described state, the automatic lead 51 is turned off, the electric lever device 47 is operated, and the controller 46 outputs a raising signal or a lowering signal to the lift solenoid proportional control valve 41 to extend or contract the lift cylinder 17 to operate the blade 18. The blade portion 18a is raised and lowered to a desired height, and the output signal of the ultrasonic sensor 32 at this time is stored in the controller 46 as a target value.

When the automatic button 51 is turned on and an automatic signal is input to the controller 46 to perform ground leveling work, and when the output signal of the ultrasonic sensor 32 changes due to the vertical displacement of the vehicle body 1 at that time, the output signal changes. The blade correction amount is calculated according to the amount, and an up signal or a down signal is output to the lift solenoid proportional control valve 41 to operate the lift cylinder 17 to extend or contract to raise or lower the blade 18 to cause the ultrasonic sensor 32.
When the output signal of 1 matches the target value, the lift electromagnetic proportional control valve 41 is set to neutral and the blade 18 is stopped.

By doing so, the height of the blade 18 is controlled so as to be parallel to the reference line.
By 8, the ground can be cut parallel to the reference line to level the ground.

Next, an operation for controlling the tilt angle of the blade 18 to be constant will be described. The left and right inclinometer 31 is the blade 18
With reference to the output signal when it is horizontal in the longitudinal direction (horizontal direction), the signal is output in proportion to the inclination angle (tilt angle) by inclining to the right and the left.

When the automatic button 51 is turned off and the electric lever 47 is operated, the tilt electromagnetic proportional control valve 4 is operated by the controller 46.
3 outputs a contraction signal to contract the tilt cylinder 21 to move the blade 18 to the right as shown by the solid line in FIG. 11A, and the tilt angle of the blade 18 at this time is detected by the left and right inclinometer 31. It is stored in the controller 46.
At this time, the blade 18 has a zero angle angle, that is, a straight posture, as indicated by the solid line in FIG.

In the above-mentioned state, the automatic button 51 is turned on and the electric lever 47 is operated to output the expansion signal or the contraction signal from the controller 46 to the left and right angle electromagnetic proportional control valves 42 to expand and contract the left and right angle cylinders 20. When the blade 18 is actuated to have a right front angle as shown by the dotted line in FIG. 10 (b), the tilt angle (hereinafter referred to as the transverse gradient) with respect to the direction orthogonal to the traveling direction of the blade 18 is the dotted line in FIG. 11 (a). It changes as shown in.

The controller 46 receives a signal proportional to the angle of the blade 18 from the angle potentiometer 3
An angle angle at which the blade 18 has moved is calculated based on the difference between the input value from 0 and the signal when the angle angle is zero, and the tilt angle correction amount is calculated based on the calculated angle angle. A contraction signal is output to contract the angle cylinder 21 to tilt the blade 18 to the lower right, and when the value coincides with the tilt angle correction amount, the tilt electromagnetic proportional control valve 43 is made neutral. This brings the cross slope of the blade 18 to its initial value.

The above operation is the same when the blade 18 is tilted leftward and the blade 18 is angled leftward.

If the blade 18 is raised or lowered while the blade 18 is tilted, the blade 1
8 changes, the amount of increase or decrease of the blade 18 is calculated according to the amount of change in the output signal of the lift potentiometer 30, and the blade tilt correction amount is calculated based on the amount of increase or decrease of the blade 18. Correct the angle.

In the above embodiment, the blade support arm 14 is pivotally attached to the front wheel 7 and the rear wheel 8 of the vehicle body 1 substantially at the center in the front-rear direction. As shown in FIG. The automatic control when the pin 15 is pivotally attached to the front wheel 7 side will be described.

In this case, as described above, the blade 18 can be vertically swung by height displacement in the same manner as described above except that the length of the blade support arm 14 is different. When the angle with respect to is controlled to be constant, the front and rear wheels 7 and 8 of the vehicle body 1 are substantially centered in the front-rear direction and the blade support arm 1 as shown in FIG.
The height H _{2 of the} blade 18 differs by a distance L _{1 from} the pivot point 4 (pin 15). For example, in FIG. 13, H ₂ = tan θ [(L ₁ + L ₂ ) −L ₂ ].

Therefore, the target angle of the blade support arm 14 is corrected according to the change in the front-back inclination angle of the vehicle body 1. For example, the target angle of the support arm 14 with respect to the horizontal is corrected by the angle θ ₁ obtained from the formula of H ₂ / L ₂ = tan θ ₁ .

[0046]

The height displacement of the blade 18 when the vehicle body 6 runs on the uneven portion is the same as the height displacement of the virtual blade C provided in the front-rear center of the front wheel 7 and the rear wheel 8 of the vehicle body 6. Thus, the height displacement of the blade 18 becomes smaller than the height displacement of the front wheels 7 and the rear wheels 8 due to the forward leaning and the backward leaning of the vehicle body 6, and the control amount thereof becomes small. Therefore,
A compact grounding vehicle having a short distance between the front wheels 7 and the rear wheels 8 can level the ground flatly with the same accuracy as the motor grader.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a ground leveling work by a motor grader.

FIG. 2 is a front view showing the first embodiment of the present invention.

FIG. 3 is a plan view of FIG.

FIG. 4 is a right side view of FIG.

FIG. 5 is a schematic plan view of a vehicle body.

FIG. 6 is a hydraulic circuit diagram.

FIG. 7 is a block diagram of a control device.

FIG. 8 is an operation explanatory diagram of an electric lever.

FIG. 9 is an explanatory diagram of a leveling operation.

FIG. 10 is an explanatory diagram of a blade height correction operation based on a pitching angle.

FIG. 11 is an explanatory diagram of a tilt angle correction operation based on an angle angle.

FIG. 12 is a front view showing a second embodiment of the present invention.

FIG. 13 is an explanatory diagram of a blade control operation.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Car body, 2 ... Horizontal member for wheel mounting, 4 ... Equalizer bar, 5 ... Rod, 6 ... Car body, 7 ... Front wheel, 8 ... Rear wheel, 14
... Blade support arm, 17 ... Lift cylinder, 18 ...
Blade, 25 ... auxiliary blade, 46 ... controller,
47 ... electric lever, 41 ... lift electromagnetic proportional control valve.

Claims (10)

[Claims] 1. A ground leveling vehicle comprising a vehicle body having a front wheel 7 and a rear wheel 8 attached to a vehicle body 6, and a blade 18 which is vertically swingable on the vehicle body 6 and projects forward from the vehicle body 6. When the vehicle travels on the uneven portion of the ground, the blade 18 is moved up and down so that the blade 18 has the same height displacement as the height displacement of the virtual blades provided substantially in the center of the front wheel 7 and the rear wheel 8 in the front-rear direction. A blade control method for a ground leveling vehicle, which comprises rocking control. 2. A ground leveling vehicle comprising a vehicle body having a front wheel 7 and a rear wheel 8 attached to a vehicle body 6, and a blade 18 which is vertically swingable on the vehicle body 6 and projects forward from the vehicle body 6, wherein the vehicle body 6 When the vehicle travels on the uneven portion of the ground, a change in the angle of the blade mounting member that supports the blade 18 to the vehicle body 6 with respect to the horizontal is detected, and the blade 18 is moved to the front wheel 7 and the rear wheel according to the change in the angle. 8. A blade control method for a ground leveling vehicle, wherein vertical swing control is performed so that the height displacement is the same as the height displacement of a virtual blade provided substantially at the center in the front-rear direction. 3. A ground leveling vehicle comprising a vehicle body having a front wheel 7 and a rear wheel 8 mounted on a vehicle body 6, and a blade 18 that is vertically swingable on the vehicle body 6 and protrudes forward from the vehicle body 6. When the vehicle runs on uneven parts of the ground,
Of the front wheels 7 and the rear wheels 8 in the front-rear direction are detected, and the blade 18 is vertically swung so that the height displacement is the same as the detected height displacement. A blade control method for a ground leveling vehicle, comprising: 4. A ground leveling vehicle comprising a vehicle body having a front wheel 7 and a rear wheel 8 mounted on a vehicle body 6, and a blade 18 which is vertically swingable on the vehicle body 6 and projects forward from the vehicle body 6. When the vehicle travels on the uneven portion of the ground, the blade 18 is moved up and down so that the blade 18 has the same height displacement as the height displacement of the virtual blades provided substantially in the center of the front wheel 7 and the rear wheel 8 in the front-rear direction. A blade control device for a ground leveling vehicle, comprising a blade control mechanism for rocking control. 5. A ground leveling vehicle comprising a vehicle body having a front wheel 7 and a rear wheel 8 mounted on a vehicle body 6, and a blade 18 which is vertically swingable on the vehicle body 6 and projects forward from the vehicle body 6, wherein the vehicle body 6 Means for detecting the angle of the blade 18 with respect to the horizontal, a means for detecting the displacement of a blade mounting member that supports the blade 18 on the vehicle body 6, a lift cylinder 17 for swinging the blade 18 up and down, and pressure oil for the lift cylinder 17. Of the virtual blades provided in the front and rear wheels 8 and 8 at substantially the center in the front-rear direction by calculating the angle change with respect to the horizontal of the blade mounting member in accordance with the signals from the respective detecting means. A blade control device for a ground leveling vehicle, comprising: a controller that outputs a switching signal of a directional control valve so that the same height displacement as the height displacement is obtained. 6. A ground leveling vehicle comprising a vehicle body having a front wheel 7 and a rear wheel 8 mounted on a vehicle body 6, and a blade 18 swingably movable up and down on the vehicle body 6 and projecting forward from the vehicle body 6. A means for detecting the height displacement of the front wheels 7 and the rear wheels 8 in the approximately central portion in the front-rear direction, and the blade 1.
8. A blade control device for a ground leveling vehicle, comprising means for vertically swinging so that its height displacement is the same as the detected height displacement. 7. A vehicle body in which a front wheel 7 and a rear wheel 8 are attached to a vehicle body 6, and a blade support arm 14 supported so as to be vertically swingable at approximately the center of the front wheel 7 and the rear wheel 8 of the vehicle body 6 in the front-rear direction.
The blade 18 attached to the blade support arm 14
A lift cylinder 17 for swinging the blade support arm 14 up and down, a first means for detecting an angle between the blade support arm 14 and the horizontal direction, and the lift cylinder 17 for the lift cylinder 17 based on a detection value of the first means. The blade control device for a ground leveling vehicle according to claim 5, further comprising second means for expanding and contracting to keep a constant angle with the horizontal of the blade support arm. 8. The vehicle front-back inclinometer 26 attached to the vehicle body 6 as the first means, and the controller 46 and the lift electromagnetic proportional control valve 41 as the second means.
A blade control device for a ground leveling vehicle as described above. 9. A front and rear direction intermediate portion of a wheel mounting cross member 2 is vertically swingably connected to the left and right of the vehicle body 1, and the left and right wheel mounting cross members 2 and the car body 1 are connected via an equalizer bar 4 and a rod 5. Connected to each other to form the vehicle body 6 and the left and right wheel mounting cross members 2
7. A blade control device for a ground leveling vehicle according to claim 4, 5 or 6, wherein front wheels 7 and rear wheels 8 are attached to said front wheels. 10. The blade control device for a ground leveling vehicle according to claim 8, wherein auxiliary blades 25 are respectively mounted between the front wheels 7 and the rear wheels 8 of the left and right wheel mounting cross members 2.