JP2521864B2 - Control device for screen working angle of civil engineering machinery - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for automatically controlling a working angle of a screed in a civil engineering machine such as an asphalt finisher for evenly laying a pavement surface.

[0002]

2. Description of the Related Art Generally, a pavement surface is finished by a screed to a substantially uniform pavement surface. To briefly explain the principle, the screed 101 has a traction force P and a synthetic force F of weight W as shown in FIG. Get to work. The screed 101 has a predetermined working angle α, and a combined reaction force R of the reaction force against the propulsive force of the screed 101 and the reaction force against the weight R
Works. The screed 101 is maintained at a constant height by balancing F and R, and it becomes possible to spread the paving material to a predetermined thickness.

When the working angle α is changed, the balance between F and R is broken, and the screed 101 is moved up and down to a position where it is balanced again, so that the pavement thickness can be changed.

The working angle α of the screed 101 can be adjusted by moving the pulling portion of the leveling arm 103 up and down by the hydraulic cylinder 105.
Is controlled by a solenoid valve 109 that switches based on a detection signal from the detection sensor 107.

[0005]

As described above, the leveling arm 10 for changing the working angle α of the screed 101.
3 moves up and down based on the detection signal from the detection sensor 107. As the detection sensor 107, a type arranged near the screed 101 as shown in the drawing and a type arranged not shown in the drawing near the towing portion are known.

A detection sensor 10 near the screed 101
In the former case where 7 is arranged, the vertical movement of the screed 101 can be accurately detected and corrected, so that a uniform paved surface can be obtained, but the height of the towing portion also increases when the machine body 111 side moves up and down due to the unevenness of the roadbed or the like. However, there is a problem that the working angle α of the screed 101 also changes.

Further, since the correction by the detection sensor 107 starts after the height of the screed 101 starts to change, follow-up control is always performed, and unevenness is likely to occur, and it is difficult to obtain a uniform paved surface.

On the other hand, in the latter case where the detection sensor is arranged near the towing unit, the position of the towing unit is immediately corrected even if the body 111 moves up and down due to the unevenness of the roadbed or the like, and the working angle α
However, since the detection switch 107 is far away from the screed 101, the vertical movement of the screed 101 cannot be accurately coped with, and problems such as small waves are generated on the pavement surface. .

In this case, as a means for solving the above-mentioned problems, for example, the mounting position of the detection sensor 107 may be arranged at an intermediate position between the former and the latter, but in reality, both defects overlap each other, and the screed 101 is vertically moved. There is a problem that both the motion detection and the up / down motion detection of the airframe have low sensitivity, and good control cannot be expected.

Therefore, an object of the present invention is to provide a control device for a screed working angle of a civil engineering machine, which solves the above problems.

[0011]

In order to achieve the above object, according to the present invention, a leveling arm for changing the working angle of the screed by vertical movement and one of which is supported by the leveling arm so as to be vertically rotatable. And a sub-arm that is vertically movably and vertically rotatably connected to the other body, and a first extendable and retractable mechanism that moves the sub-arm up and down with respect to the other body on the side of the body And a leveling arm, which is capable of expanding and contracting to vertically rotate the leveling arm, and a machine body detection sensor which is supported by either one of the sub arm and the machine body near the sub arm and which detects the vertical movement of the machine body. ,
A screed detection sensor that is supported by one of the screed and a leveling arm near the screed and that detects the vertical movement of the screed, and a sub-arm integrally connected to the leveling arm based on a detection signal from the machine body detection sensor. First driving means for expanding and contracting the first expansion and contraction mechanism so as to move up and down relative to the machine body in a fixed state, and the leveling arm rotates up and down with respect to the sub arm based on a detection signal from the screed detection sensor. It comprises a second drive means for expanding and contracting the second expansion and contraction mechanism.

[0012]

According to such a screed working angle control device,
For example, when the screed detection sensor detects the vertical movement of the screed, the second drive means operates based on the detection signal, and the leveling arm is vertically rotated with respect to the sub-arm by the extension or contraction of the second expansion / contraction mechanism, and the appropriate movement is achieved. The working angle of the screed can be obtained.

On the other hand, when the vertical movement of the machine body is detected by the machine body detection sensor, the first drive means operates based on the detection signal, and as a result, the first expansion / contraction mechanism expands and contracts without being affected by the vertical movement of the machine body. The pulling point of the leveling arm is always kept at a fixed position with respect to the reference plane.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings of FIGS.

In the figure, reference numeral 1 shows a machine body such as an asphalt finisher which can be traveled by a traveling device 3 such as a caterpillar. Although not shown, the machine body 1 includes a hopper for charging the paving material, a transportation device (not shown) such as a bar feeder for feeding the paving material charged into the hopper backward,
It has a spiral lateral feed device 5 that spreads the paving material that has been sent rearward to the left and right, and a screed 7 that evenly spreads the paving material that has spread to the left and right.

The screed 7 is formed to be long in the vehicle width direction and is supported by a leveling arm 9 which is long in the front-rear direction. The working surface serving as the bottom surface of the screed 7 has a working angle α that is changed by the vertical movement of the leveling arm 9 (chain line in FIG. 1).

The front of the leveling arm 9 is supported by the rear portion of the sub-arm 11 so as to be vertically movable via a pivot shaft 14 serving as a pulling point. A front end portion of the sub-arm 11 is rotatably connected to a tow hitch 15 that vertically moves along upper and lower guy rails 13 fixed to the machine body 1 by a connecting shaft 16.

The sub-arm 11 and the leveling arm 9 are vertically movably controlled by a first telescopic mechanism 17 and a second telescopic mechanism 19.

That is, the first extension mechanism 17 and the second extension mechanism 1
Reference numeral 9 is composed of a cylinder 21 and a piston rod 23 that reciprocates in the cylinder 21.
When the oil is fed into the chamber 21a, the piston rod 2
3 is a double-acting type that expands and contracts when oil is fed into the second chamber 21b. The cylinder 21 of the first extension / contraction mechanism 17 is pivotally supported by the machine body 1, and the piston rod 23 is pivotally supported by the tow hitch 15. As a result, the sub arm 11 can be lowered by the extension of the piston rod 23 and can be raised by the contraction.

The cylinder 21 of the second extension / contraction mechanism 19
Is a piston rod 2 at approximately the middle of the sub arm 11.
3 are pivotally supported at the tip of the leveling arm 9. As a result, the extension of the piston rod 23 allows the leveling arm 9 to rise on the rear end side (on the right side in FIG. 1) with the pivot shaft 14 as a fulcrum, and to lower by contracting.

FIG. 2 shows a first hydraulic circuit 25 for controlling the first expansion / contraction mechanism 17 and a second hydraulic circuit 27 for controlling the second expansion / contraction mechanism 19, respectively.

The first hydraulic circuit 25 is provided with a switching control valve 29 having spool valves S ₁ and S ₂ which are connected to and communicate with the intake-side and extraction-side ports P ₁ , P ₂ , P _3, and P ₄ , respectively. , The oil pressure of the hydraulic pump 31 is in the tank 3 at the neutral time.
I will come back to 3. Further, as shown in FIG. 3, when one spool valve S ₁ is connected and communicates with the ports P ₃ and P ₄ from the neutral position, the hydraulic pressure from the hydraulic pump 31 causes the first chamber 21a of the cylinder 21 of the first expansion and contraction mechanism 17 to have a hydraulic pressure. Sent to.
Further, as shown in FIG. 4, the other spool valve S ₂ is connected to the port P.
_By connecting and communicating with ₃ · P ₄ , the hydraulic pressure from the hydraulic pump 31 allows the second chamber 21 of the cylinder 21 of the first extension / contraction mechanism 17 to be connected.
sent to b.

Further, each spool valve S ₁ of the switching control valve 29
The switching of S ₂ is controlled based on a detection signal from the sub arm 11 or a machine body detection sensor 39 supported by the machine body 1 near the sub arm 11.

The machine body detection sensor 39 detects the vertical movement of the machine body 1 during traveling by the sensor section 39a and outputs a signal for raising or lowering.

The second hydraulic circuit 27 is provided with a switching control valve 43 having spool valves S ₁ and S ₂ connected and communicating with the intake-side and extraction-side ports P ₁ , P ₂ , P _3, and P _4. , The oil pressure of the hydraulic pump 31 is in the tank 3 at the neutral time.
I will come back to 3. Further, as shown in FIG. 5, when one spool valve S ₁ is connected and communicates with the ports P ₃ and P ₄ from the neutral position, the hydraulic pressure from the hydraulic pump 31 causes the hydraulic pressure from the hydraulic pump 31 to move to the first chamber 21a of the cylinder 21 of the second expansion and contraction mechanism 19. Sent to.
Further, as shown in FIG. 6, the other spool valve S ₂ is connected to the port P.
_By connecting and communicating with ₃ · P ₄ , the hydraulic pressure from the hydraulic pump 31 allows the second chamber 21 of the cylinder 21 of the second expansion / contraction mechanism 19 to have a hydraulic pressure.
sent to b.

The switching control valve 43 is switching-controlled based on a detection signal from the screed 7 or a screed detection sensor 45 supported by the leveling arm 9 near the screed 7.

The sensor section 45 of the screed detection sensor 45
a becomes capable of traveling along the reference surface 41, and the screed 7
It detects the vertical movement of the and outputs a signal for raising or lowering.

In the hydraulic circuit, 47 is a pilot check valve. This check valve 47
Has a function of allowing the hydraulic pressure in the first chamber 21a or the second chamber 21b of the cylinder 21 to escape to the tank 33 when the pilot pressure acts by the circuit shown by the dotted line.

According to the screed working angle control device thus constructed, for example, when the machine body detection sensor 39 detects the vertical movement of the machine body 1, an up or down signal is output, and based on the signal, The hydraulic circuit 25 of No. 1 works, and the 1st expansion-contraction mechanism 17 expand-contracts. At this time, the second extension / contraction mechanism 19 does not extend / contract, and the sub-arm 11 and the leveling arm 9 do not move relative to each other and are in a fixed state in which they are integrally coupled.

As a result, the pulling point of the leveling arm 9 is always affected by the vertical movement of the machine body 1 and the reference plane 41
The condition of a constant position with respect to is secured, and the working angle (angle of inclination of the lower surface of the screed 7 with respect to the reference surface 41) α of the screed 7 does not change.

At the same time, when the screed detection sensor 45 detects the vertical movement of the screed 7 while the operation for ensuring the constant condition is being performed, a signal for raising or lowering is output, and based on the signal. The second hydraulic circuit 27 also works, the second expansion / contraction mechanism 19 expands / contracts, and the pivot 1
4, the leveling arm 9 rotates up and down with respect to the sub arm 11, and the screed 7 is moved up and down together with the leveling arm 9. As a result, the screed 7 can always obtain a working angle α that provides a constant pavement thickness without being affected by conditions such as the machine body 1 and the pavement surface.

In this embodiment, the hydraulic means is adopted, but it is also possible to electrically control by a servomotor or the like.

[0033]

As described above, according to the screed working angle control device of the present invention, the up and down movement of the machine body and the up and down movement of the screed can be detected by the machine body detection sensor and the screed detection sensor, respectively. Along the reference plane without being affected by running conditions and uneven conditions,
Moreover, it becomes possible to secure a working angle of the screed that can obtain a constant pavement thickness, and a uniform pavement surface can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a screed working angle control device of the present invention.

FIG. 2 is a first and second hydraulic circuit diagram.

FIG. 3 is an operation explanatory diagram.

FIG. 4 is an operation explanatory diagram.

FIG. 5 is an operation explanatory diagram.

FIG. 6 is an operation explanatory diagram.

FIG. 7 is an explanatory view similar to FIG. 1 showing a conventional example.

[Explanation of symbols]

 1 Aircraft 7 Screed 9 Leveling Arm 11 Sub Arm 17, 19 First and Second Extension Mechanism 25 First Hydraulic Circuit (Drive Means) 27 Second Hydraulic Circuit (Drive Means) 39 Aircraft Detection Sensor 45 Screed Detection Sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Kobayashi 1-4-1 Kasumigaseki, Chiyoda-ku, Tokyo Inside Niigata Iron Works Co., Ltd. (72) Inventor Hirokazu Watanabe 1-4-1 Kasumigaseki, Chiyoda-ku, Tokyo Niigata Construction Machinery Co., Ltd. Inspector Tsuneaki Onomura (56) Reference JP-A-3-166405 (JP, A)

Claims (1)

(57) [Claims] 1. A leveling arm for changing a working angle of a screed by a vertical movement, one of which is rotatably supported by the leveling arm vertically and the other of which is vertically movably and vertically rotatably connected to an airframe. And a first expandable / contractible mechanism for moving the sub-arm up and down with respect to the machine body on the other side of the machine body, and an expandable and contractible first arm for vertically rotating the leveling arm between the sub-arm and the leveling arm. 2 Telescopic mechanism, a body detection sensor that is supported by one of the sub-arm and the body near the sub-arm to detect vertical movement of the body, and a screed supported by either one of the screed and the leveling arm near the screed. A screed detection sensor for detecting vertical movement, and a sub arm based on a detection signal from the machine body detection sensor. A first drive means for expanding and contracting the first expansion and contraction mechanism so as to move up and down with respect to the machine body in a fixed state integrally coupled with the leveling arm; and the leveling arm based on a detection signal from the screed detection sensor. A screed working angle control device for a civil engineering machine, comprising: a second drive unit that extends and retracts the second extension mechanism so as to rotate up and down with respect to the sub arm.