JPH0768684B2 - Laying machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a leveling machine such as an asphalt finisher used for paving a pavement material such as an asphalt mixture material on a roadbed to make a road.

[Conventional technology]

In the conventional asphalt finisher, since the asphalt mixture is compacted by the screed's own weight, the difference in hardness of the mixture changes the amount of sinking of the screed with respect to the mixture and the thickness of the mixture after paving. However, there is a drawback that they are different.

Therefore, the applicant of the present invention lifts the screed with a force smaller than the weight of the screed by being reduced by the hydraulic oil supplied from the hydraulic source to the weight reduction side cylinder chamber between the traveling vehicle body and the screed by the piping. We have developed a leveling machine that is equipped with a hydraulic cylinder that works like this, and a pressure reducing valve that reduces the pressure of hydraulic oil in the pipe (actual flat 2
-129407 publication).

According to this new leveling machine, even if the asphalt mixture is soft, the hydraulic cylinder is activated to substantially reduce the weight of the screed and keep the amount of sinking constant, thus maintaining the thickness of the asphalt mixture. The thickness can be accurately set to a predetermined value.

[Problems to be Solved by the Invention]

However, the pressure reducing valve is generally in the pressure reducing range (pressure adjusting range).
Therefore, the apparent weight of the screed cannot be adjusted within the range of 100%. That is, if there is a screed having a self-weight of 2000 kg, it can be said that the apparent self-weight can be adjusted only in the range of 0 to 1800 kg in the above-mentioned conventional leveling machine, and a dropout portion between 1800 and 2000 kg can be made. There is inconvenience. The value of 1800 kg depends on the pressure reducing valve etc. and cannot be said in a general way.

Further, the pavement thickness of the asphalt mixture changes subtly with the inclination of the paved road surface in the front-rear direction or the left-right direction, or the leveling speed, and cannot be ignored if the changing conditions overlap, but the above-mentioned conventional The leveling machine is dissatisfied with the fact that it cannot follow the change in the pavement thickness with high precision. This is a major drawback in an automatic leveling machine that automatically controls pavement thickness.

INDUSTRIAL APPLICABILITY The present invention provides a laying machine capable of remotely and instantly making the apparent weight of a screed lighter or heavier than the actual weight of the screed, thereby accurately paving various paving materials. The purpose is to provide.

[Means for Solving the Problems]

In order to achieve the above object, a leveling machine according to the present invention provides a traveling vehicle with a leveling arm capable of swinging up and down, and laying a paving material on a swinging end of the leveling arm. In a leveling machine equipped with a leveling screed, between the traveling vehicle and the screed is extended by hydraulic oil supplied from the hydraulic power unit to the weight side cylinder chamber through the first pipe to push the screed downward, Further, a hydraulic cylinder that is reduced by the hydraulic oil supplied from the hydraulic power unit to the depressurizing side cylinder chamber through the second pipe to lift the screed with a force smaller than the weight of the screed is provided, and the first pipe is connected to the first pipe. , Reduces the hydraulic oil supplied from the hydraulic power unit to the weight side cylinder chamber to a set pressure, remote to any set pressure A first pressure reducing valve with a adjustable relief mechanism is provided, and the second pipe is configured to reduce the hydraulic oil supplied from the hydraulic power unit to the weight reducing side cylinder chamber to a set pressure, which can be remotely set to any set pressure. A second pressure reducing valve with a relief mechanism is provided.

[Action]

When hydraulic oil is supplied to the weight side cylinder chamber, the hydraulic cylinder extends and pushes the screed downward. At this time, the first pressure reducing valve operates to keep the hydraulic oil at the set pressure. The screed increases the apparent weight because it is pushed by the hydraulic cylinder.

When hydraulic fluid is supplied to the weight reducing side cylinder chamber, the hydraulic cylinder contracts and urges the screed upward. On this occasion,
The second pressure reducing valve works to keep the hydraulic oil at the set pressure. The screed is urged upward by the hydraulic cylinder, which reduces the apparent weight.

〔Example〕

An embodiment applied to the asphalt finisher of the present invention will be described below with reference to the drawings.

Reference numeral 1 in FIG. 1 denotes a traveling vehicle of an asphalt finisher AF whose basic structure is well known. This traveling vehicle 1
Is composed of a vehicle body 2, wheels 3, a driver's seat 4, and the like.

A hopper 5 for storing an asphalt mixture (paving material) is provided in the front part of the vehicle body 2 of the traveling vehicle 1. The asphalt mixture in the hopper 5 is transferred to the rear of the vehicle body (rightward in FIG. 1) by a feeder (not shown) at the lower part of the vehicle body, and then spread evenly left and right by a screw (not shown) to form a left-right pair. The screed 6 of FIG.

The screed 6 is attached to the vehicle body of the traveling vehicle 1 in a suspended state at a swinging end of a leveling arm 7 that is vertically swingably provided, and is of a floating type.

The front ends of the leveling arms 7 are pivotally supported by the vehicle body 2 via support shafts 8 on both sides of the vehicle body 2 and extend in the front-rear direction of the vehicle body 2. The screed 6 is attached. The support shaft 8 is
It is adapted to be moved up and down by the pivot cylinder 9.

A hydraulic cylinder 10 is provided between the driver's seat 4 and the screed. This hydraulic cylinder 10
Cylinder body 10a and rod 10b
The end of a is connected to the driver's seat 4 and the end of the rod 10b is connected to the rear end of the leveling arm 7 so as to be rotatable.

Reference numeral 11 in FIG. 2 indicates a hydraulic circuit connected to the hydraulic cylinder 10. Reference numeral 12 in the drawing denotes a hydraulic power unit and 13
Is a relief valve, and 14 and 15 are pressure reducing valves with a relief mechanism. The pressure reducing valve 14 is a pipe connecting the hydraulic power unit 12 to the weight (extension) side cylinder chamber Sa of the hydraulic cylinder 10.
The pressure reducing valve 15 provided in the Pa is provided in the hydraulic power unit 12
Is provided in the pipe Pb connected to the weight reduction (reduction) side cylinder chamber Sb of the hydraulic cylinder 10, and both pressure reducing valves 14 and 15 can be remotely operated.

Note that FIG. 2 shows only the basic configuration of the hydraulic circuit. In practice, the pipe Pa between the pressure reducing valve 14 and the cylinder chamber Sa has a pressure reducing valve 14 when the hydraulic cylinder 10 is reduced. When the hydraulic cylinder 10 is extended, a relief circuit is provided to disconnect the hydraulic fluid in the cylinder chamber Sa to the oil tank by disconnecting from the cylinder chamber Sa, and to the pipe Pb between the pressure reducing valve 15 and the cylinder chamber Sb. A relief circuit is provided for disconnecting the pressure reducing valve 15 and the cylinder chamber Sb to release the hydraulic oil in the cylinder chamber Sb to the oil tank.

According to the asphalt finisher AF described above, the hydraulic cylinder 10 allows the screed 6 to obtain a desired paving pressure via the leveling arm 7, and the set pressures of the pressure reducing valves 14 and 15 in the hydraulic circuit 11 in the hydraulic cylinder 10 are set. By remotely setting to any value, the hydraulic cylinder 10
The advancing output of the rod 10b is changed to adjust the surface pressure of the screed 6 on the pavement surface.

That is, when hydraulic oil is supplied to the weight side cylinder chamber Sa,
Since the hydraulic cylinder 10 extends and pushes the screed 6 downward, the apparent weight of the screed 6 increases, and the asphalt mixture is spread with a force larger than the self-weight of the screed 6. When the asphalt mixture is hard, the pavement thickness is set to a predetermined value by performing the above operation.

Further, when hydraulic oil is supplied to the weight reducing side cylinder chamber Sb, the hydraulic cylinder 10 contracts and biases the screed 6 upward, so that the apparent weight of the screed 6 is reduced and the asphalt mixture material is less than the own weight of the screed 6. It is spread with a small force. When the asphalt mixture is soft, the pavement thickness is set to a predetermined value by operating in this way.

Both pressure reducing valves 14 and 15 can be operated remotely, so if the pavement conditions such as the hardness of the asphalt mix change, the pressure reducing valve set pressure can be immediately adjusted by remote control without paving. continue.

〔The invention's effect〕

As described above, in the leveling machine of the present invention, the traveling vehicle is provided with the leveling arm capable of swinging up and down, and the swinging end of the leveling arm is provided with the screed for spreading the leveling material. In the installed leveling machine, between the traveling vehicle and the screed, the hydraulic oil is extended from the hydraulic power unit to the load side cylinder chamber through the first pipe to push the screed downward, and also from the hydraulic power unit. A hydraulic cylinder is installed in the depressurization side cylinder chamber to reduce the hydraulic oil supplied through the second pipe to lift the screed with a force smaller than the weight of the screed. The operating oil supplied from the power unit to the weight side cylinder chamber is reduced to the set pressure, which can be set remotely to any set pressure. A first pressure reducing valve with a relief mechanism is provided, and the second pipe reduces the operating oil supplied from the hydraulic power unit to the depressurizing side cylinder chamber to a set pressure, which can be remotely set to any set pressure. Since the second pressure reducing valve with a relief mechanism is provided,
It has the following effects.

By using the second pressure reducing valve, the weight of the screed can be substantially reduced, and by using the first pressure reducing valve, the above-mentioned missing portion of the second pressure reducing valve is filled to reduce the apparent weight of the screed. It can be larger than the actual weight.

Therefore, the apparent weight of a screed having an actual weight of 2000 kg is, for example, 0 to 3000 kg (when the pressing force of the hydraulic cylinder 10 is 1000 kg. However, provided that the traveling vehicle 1 does not float and does not interfere with traveling. It is possible to improve the accuracy of the pavement thickness by adapting it to the pavement condition within the range of (.

Since the set pressure of both pressure reducing valves can be freely adjusted by remote control, even if the paving conditions change from moment to moment, the apparent weight of the screed can be adjusted immediately in response to the paving without interruption. You can continue to.

[Brief description of drawings]

FIG. 1 is a side view of an asphalt finisher to which the present invention is applied, and FIG. 2 is a hydraulic circuit connected to a hydraulic cylinder. 1 ... traveling vehicle, 6 ... screed 7 ... leveling arm, 10 ... hydraulic cylinder 14,15 ... pressure reducing valve, Pa, Pb ... piping Sa, Sb ... cylinder chamber AF ... asphalt finisher (laying machine).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenichi Nakabachi, 730, Mitsutaka, Gunma-gun, Gunma-gun Gunma Prefecture Niigata Iron Works Takasaki Plant (72) Ichiro Yamaguchi, 27, Isogo-cho, Isogo-ku, Yokohama, Kanagawa Prefecture Niigata Iron Works Development Center Co., Ltd. (56) References JP-A-60-23503 (JP, A) Actual Kaihei 2-129407 (JP, U)

Claims (1)

[Claims] 1. A leveling machine in which a traveling vehicle is provided with a leveling arm capable of swinging up and down, and a swinging end of the leveling arm is provided with a screed for leveling paving material. Between the traveling vehicle and the screed, from the hydraulic power unit to the load side cylinder chamber
The screed is stretched by the hydraulic oil supplied through the pipe to push the screed downward, and is reduced by the hydraulic oil supplied from the hydraulic power unit to the weight reduction side cylinder chamber through the second pipe so that the screed is less than the weight of the screed. A hydraulic cylinder that acts so as to lift it with a small force is provided, and the first pipe reduces the operating oil supplied from the hydraulic power unit to the weight side cylinder chamber to a set pressure, and can be set remotely to any set pressure. A first pressure reducing valve with a relief mechanism is provided, and the second pipe is
A leveling machine characterized by being provided with a second pressure reducing valve with a relief mechanism capable of remotely setting an arbitrary set pressure for reducing the working oil supplied from the hydraulic power unit to the depressurizing side cylinder chamber to a set pressure. .