WO2016042927A1 - Asphalt finisher - Google Patents

Abstract

The present invention heats an asphalt mixture loading part uniformly to a high temperature in a short time, compared to prior art. An inner steel plate 11, an outer steel plate 12, an electric heating sheet 13, a heat insulating sheet 14, and a convection layer 15 form a heating device 10 which heats an asphalt mixture loading part 3. A hopper 6 or the like has a double-plate structure. Between the inner steel plate 11 and the outer steel plate 12, a space extending along the steel plate surfaces is formed. The electric heating sheet 13 is in close contact with the inner side of the inner steel plate 11. The heat insulating sheet 14 is in close contact with the inner side of the outer steel plate 12. Between the electric heating sheet 13 and the heat insulating sheet 14, the convection layer 15 is formed.

Description

Asphalt finisher

The present invention relates to an asphalt finisher that stores and spreads an asphalt mixture.

Generally, an asphalt mixture is manufactured at a compound factory, transported by a dump truck, and charged into an asphalt mixture input section of an asphalt finisher. The asphalt mixture charging unit has a hopper that loads and temporarily stores the charged asphalt mixture, and a bar feeder that conveys the loaded asphalt mixture to the screed side. The asphalt mixture conveyed to the screed side is spread and leveled to perform pavement construction.

By the way, the asphalt mixture is required to be paved in a preset temperature range from the viewpoint of ensuring quality. On the other hand, depending on the geographical conditions such as cold regions and mountainous regions, the cold season, and nighttime construction conditions, problems such as rapid temperature drop of the asphalt mixture and difficulty in obtaining a predetermined degree of compaction are likely to occur. In some cases. In addition, there is a possibility that problems such as dragging and dragging holes on the leveling surface and problems such as insufficient adhesion of the joint portion of the pavement may occur.

For this reason, it is preferable to avoid asphalt pavement construction in a low temperature environment where the outside temperature is 5 ° C. or less. In particular, in drainage pavement that requires a gap between asphalt mixtures, strict temperature control is required because there is a risk of quality deterioration due to a temperature drop.

However, there are cases where construction in an environment where the outside air temperature is low is unavoidable from the viewpoint of ordering schedule and year-round construction, and some measures are necessary. For example, measures can be taken such as slightly raising the temperature of the asphalt mixture at the time of shipping to the composite material factory, or placing a heat insulating sheet on the loading platform of the dump truck during transportation. On the other hand, the heat released between the asphalt finisher and the paving work after the asphalt mixture is charged cannot be ignored.

In the asphalt finisher of Patent Document 1, a hopper and a bar feeder having a preheating function that reuses exhaust generated during engine warm-up operation have been proposed. According to the prior art, by applying preheating to the hopper and the bar feeder before the asphalt mixture is charged, even if the asphalt mixture initially charged in a low temperature environment contacts the surface of the hopper or bar feeder, The temperature drop of the asphalt mixture can be suppressed. Furthermore, after the asphalt mixture is charged and during paving, the asphalt mixture can be kept warm, and the temperature drop of the asphalt mixture can be suppressed.

JP 2013-113028 A

However, since the conventional technique according to Patent Document 1 reuses exhaust gas, it has the following problems.

¡In order to reuse exhaust gas generated during engine warm-up operation, the temperature of the hopper after preheating is about 60 degrees at the maximum. Since the temperature of the asphalt mixture charged from the dump truck is usually about 150 to 200 ° C., the preheating temperature is preferably as high as possible.

According to the actual construction example, the elapsed time from the start of the engine to the maximum temperature was about 30 to 90 minutes. From the viewpoint of shortening the construction period, it is preferable that the time to reach the set preheating temperature is short.

In the prior art, exhaust is caused to flow through a flow path provided in two steel plates. If the distance between the steel plates is not less than 25 mm and the channel width is not more than 200 mm, the channel does not function sufficiently. In consideration of the size of the flow path, there is a portion where the flow path is not provided in the hopper or the bar feeder, and as a result, temperature unevenness may occur.

Furthermore, for example, a flow path cannot be provided in the front wing or the like.

Also, the exhaust temperature is different between the upstream and downstream of the flow path, and there is a risk of temperature unevenness.

In the prior art, the preheating temperature is passively determined, but it is preferable that the preheating temperature can be set and adjusted principally. Furthermore, it is preferable that the preheating temperature can be partially set and adjusted.

This invention solves the said subject, and aims at providing the asphalt finisher which can heat an asphalt mixture injection | throwing-in part to high temperature uniformly in a short time compared with a prior art.

The asphalt finisher of the present invention that solves the above problems includes a heating device. The heating device heats the asphalt mixture charging part of the asphalt finisher. The heating device includes an inner plate member, an outer plate member, and a planar electric heating device. The inner plate member and the outer plate member face each other and constitute a part of the asphalt mixture charging part. The planar electric heating device is in close contact with the inner side of the inner plate member.

The asphalt mixture charging part can be heated to a high temperature in a short time without unevenness by the planar electric heating device.

Preferably, in the above invention, the asphalt mixture charging portion is composed of constituent members such as an upper hopper wing, a lower hopper wing, a hopper rear surface, a front wing, a rear plate, and a bar feeder. The heating device is provided in one or more of the components.

It can be applied in a wide range by downsizing with a planar electric heating device.

In the above invention, preferably, a plurality of the planar electric heating devices are provided. The plurality of planar electric heating devices are electrically in parallel.

This makes it possible to set the set temperature individually.

In the above invention, preferably, in the plurality of planar electric heating devices, the set temperature of the planar electric heating device provided at the lower position is set to be equal to or higher than the set temperature of the planar electric heating device provided at the upper position. For example, the set temperature of the planar electric heating device provided in the lower hopper wing is set so as to be equal to or higher than the set temperature of the planar electric heating device provided in the upper hopper wing.

Thereby, a sufficient preheating effect can be obtained even on the downstream side.

Preferably, in the above invention, a corner portion is formed in a continuous portion between the upper hopper wing and the lower hopper wing of the asphalt mixture charging portion. A plurality of planar electric heating devices are provided in the upper hopper wing and / or the lower hopper wing. In the plurality of planar electric heating devices, the set temperature of the planar electric heating device closest to the corner is set to be equal to or higher than the setting temperature of the other planar electric heating devices.

This makes it difficult for the asphalt mixture to clump at the corners, ensuring pavement quality.

Preferably, in the above invention, the heating device has a three-layer structure of a planar electric heating device, a convection layer, and a heat insulating sheet. The heat insulating sheet is in close contact with the inside of the outer plate member. A convection layer is provided between the planar electric heating device and the heat insulating sheet.

¡Temperature unevenness is further reduced by the convection layer. In particular, a synergistic effect can be expected by combination with electrical parallel.

According to the present invention, it is possible to heat the asphalt mixture charging section in a short time and uniformly at a high temperature as compared with the prior art. As a result, the temperature drop of the asphalt mixture can be more reliably suppressed by preheating and heat retention than in the prior art.

Schematic diagram of asphalt finisher Configuration diagram of asphalt mixture charging unit 3 Bar feeder configuration diagram Configuration diagram of the heating device Example of power consumption allocation Power consumption allocation example (center front and left details) Example of power consumption allocation (detailed right side)

~ Configuration ~
The structure of the asphalt finisher according to this embodiment will be described.

FIG. 1 is a schematic configuration diagram of an asphalt finisher. The asphalt finisher includes a crawler 1 for traveling, a driver's seat 2 for an operator to perform driving work, an asphalt mixture input unit 3 provided in front of the driver's seat 2 and into which the asphalt mixture is input from a dump truck, Various member devices such as a screw spreader 4 provided behind the driver's seat 2 for uniformly spreading the asphalt mixture to the paving width, and a screed 5 with a tamper provided behind the screw spreader 4 for compacting the asphalt mixture. It is composed of

FIG. 2 is a configuration diagram of the asphalt mixture charging unit 3. The asphalt mixture charging unit 3 includes a hopper 6, a bar feeder 7, a rear plate 8, and a front wing 9.

The hopper 6 is formed by opposingly arranging a pair of outer plates that are substantially L-shaped on the left and right with the bar feeder 7 in between. The outer plate of the hopper 6 has a posture in which the bottom plate surface is substantially parallel to the bar feeder 7 by the expansion and contraction operation of the cylinder (usually, in this posture, the asphalt mixture is introduced and temporarily stored) and the left and right outer sides are The posture can be changed to lift and slide the asphalt mixture to the bar feeder 7 side.

The hopper 6 includes a side upper step 61, a side lower step 62, and a hopper rear surface 63. The upper side surface 61 and the lower side surface 62 are continuous so as to form a substantially L-shaped wing. The substantially L shape has a corner portion 64. The hopper rear surface 63 is arranged corresponding to a substantially L-shape.

The bar feeder 7 conveys the charged asphalt mixture backward. The bar feeder 7 includes a bottom plate 71 and a rotating portion 72 that is rotatably arranged around the bottom plate (FIG. 3).

The rear plate 8 is provided in front of the driver's seat 2 and constitutes a part of the asphalt finisher main body. While the hopper 6 is variable, the rear plate 8 is unchanged.

As a characteristic configuration of the present embodiment, the asphalt mixture charging unit 3 includes a heating device 10.

The heating device 10 is provided in the hopper 6 in principle, but may be provided in the bar feeder 7 (bottom plate 71), the rear plate 8, and the front wing 9.

Further, in the asphalt finisher of the prior art (Patent Document 1), the heating device 10 may be provided on the rear plate 8 and / or the front wing 9.

FIG. 4 is a configuration diagram of the heating device 10. Although the example provided in the hopper 6 is demonstrated, the example provided in the bar feeder 7, the rear board 8, and the front wing 9 is also the same structure.

The hopper 6 has a double plate structure composed of two steel plates 11 and 12, and a space extending along the steel plate surface is formed between the inner steel plate 11 and the outer steel plate 12. Here, the side into which the asphalt mixture is charged is the inside.

The electric heating sheet 13 is in close contact with the inner side (space side) of the inner steel plate 11. The electric heating sheet 13 is a sheet formed by meandering heating wires, and generates heat due to electric resistance during energization. The power source of the electric heating sheet 13 is a generator and a battery that are standardly installed in the asphalt finisher main body. However, when a sufficient amount of electricity cannot be supplied, an additional generator is mounted on the asphalt finisher.

The heat insulating sheet 14 is in close contact with the inner side (space side) of the outer steel plate 12. A convection layer (space) 15 is formed between the electric heating sheet 13 and the heat insulating sheet 14.

For example, the thickness of the electrothermal sheet 13 is 3 mm, the thickness of the convection layer 15 is 5 mm, and the thickness of the heat insulating sheet 14 is 4 mm. A three-layer structure is formed at a distance of 12 mm between the steel plates.

The heating device 10 is provided individually for each of the upper side surface 61, the lower side surface 62, and the hopper rear surface 63. The electrothermal sheets 13 provided on the respective constituent members 61 to 63 are electrically in parallel.

Further, in each of the constituent members 61 to 63, the region is divided into a plurality of regions, and the electrothermal sheet 13 is electrically arranged in parallel for each region. In principle, the power consumption of the electric heating sheet 13 is set based on the area of the region. FIG. 5 is an example of power consumption allocation. FIG. 5A shows a general overview, FIG. 5B shows details of the left side and center front, and FIG. 5C shows details of the right side.

A temperature sensor 16 is provided on the inner steel plate 11 corresponding to each electric heating sheet 13. The control device 17 (not shown) adjusts the energization amount so that the temperature detected by the temperature sensor 16 becomes a set temperature (for example, 80 degrees).

Furthermore, an outside air sensor 18 (not shown) may be provided, and the control device 17 may vary the set temperature between 50 and 120 degrees based on the temperature detected by the outside air sensor 18. Specifically, the lower the outside air temperature, the higher the set temperature.

In the present embodiment, the inner steel plate 11, the outer steel plate 12, the electric heating sheet 13, the heat insulating sheet 14, the convection layer 15, the temperature sensor 16, and the control device 17 constitute a heating device 10 that heats the asphalt mixture charging unit 3. .

-Construction-
An asphalt pavement method using the asphalt finisher of the present embodiment will be described.

Generally, the asphalt mixture is manufactured at a compound factory and transported to a construction site by a dump truck. The asphalt finisher waits until the dump truck arrives at the construction site.

Generally, countermeasures are required for construction in an environment where the outside air temperature is 5 ° C or lower. Furthermore, it is preferable to suppress the temperature drop of the asphalt mixture even in an environment where the outside air temperature is low.

During standby, the asphalt finisher preheats (heats) the asphalt mixture charging unit 3 as a temperature drop suppression measure.

When the inventor of the present application conducted a confirmation test, the surface temperature of the hopper 6 reached the set temperature (80 ° C.) in about 20 minutes by the heating device 10 under the environment of the outside air temperature of 5 ° C.

After the set temperature is reached, the control device 17 maintains the set temperature. In this state, the asphalt mixture is put into the hopper 6 from the dump truck. The temperature of the asphalt mixture charged from the dump truck is usually about 150 to 200 ° C. When the asphalt mixture at about 150 to 200 ° C. was brought into contact with the surface of the hopper 6 that had been preheated to 80 ° C., the temperature detected by the temperature sensor 16 became 120 ° C. or higher. It is presumed that the temperature of the asphalt mixture that is initially charged and contacts the surface of the hopper 6 is also 120 ° C. or higher.

The asphalt mixture temporarily stored in the hopper 6 is conveyed by the bar feeder 7, spread by the screw spreader 4, and spread by the screed 5. The heating apparatus 10 continues to operate after the asphalt mixture is charged and also during paving. The preheat application function operates as a heat retention function.

~ Effect ~
-Comparison with the prior art (exhaust gas reuse) Whereas the maximum heating temperature of the prior art is 60 degrees, in this embodiment, it can be heated to 120 degrees.

In the prior art, the elapsed time from the start of the engine to reaching the maximum temperature was about 30 to 90 minutes. In contrast, in the present embodiment, the set temperature is reached in 20 to 60 minutes.

In the prior art, there is a component member (for example, front wing) that cannot be heated because an exhaust passage is not provided from the viewpoint of size. In addition, there were places where the exhaust passage was not provided even in the hopper. As a result, temperature unevenness may occur. On the other hand, in the present embodiment, the heating device 10 can be installed on the bar feeder 7, the rear plate 8, and the front wing 9 by downsizing the heating device 10. Moreover, it is also possible to install the heating apparatus 10 in almost the entire area of the hopper 6. Thereby, it can heat evenly.

In the prior art, there is a risk of temperature unevenness between the upstream and downstream of the flow path, whereas in this embodiment, heating can be performed without any unevenness in this point.

In the prior art, the preheating temperature depends on the outside air temperature and the exhaust temperature (passive), whereas in this embodiment, the preheating temperature can be set and adjusted (primary).

Thus, as compared with the prior art, the asphalt mixture charging unit 3 can be heated in a short time without unevenness at a high temperature, and the temperature drop of the asphalt mixture can be reliably suppressed.

-Effect by further characteristic structure By the way, as above-mentioned, in this embodiment, it can heat evenly compared with a prior art. On the other hand, places (for example, corners and narrow portions) where the electric heating sheet 13 cannot be installed closely remain. Heat cannot be generated between the electric heating sheets 13. Further, the electric heating sheet 13 is not always able to generate heat uniformly due to the arrangement of the heating wires. Minute unevenness occurs in heat generation at a portion corresponding to the heating wire and a portion corresponding to the space between the heating wires. In other words, the problem relating to temperature unevenness remains slight.

In the present embodiment, the heating device 10 includes a heat insulating sheet 14 and a convection layer 15. The heat from the electric heating sheet 13 is directly transmitted to the inner steel plate 11, and after being circulated through the convection layer 15, is indirectly transmitted to the inner steel plate 11. Thereby, temperature unevenness is reduced.

In this embodiment, the region is divided into a plurality of regions, and the electrothermal sheet 13 is electrically arranged in each region in parallel. Thereby, the preset temperature of the electric heating sheet 13 in each region can be individually set (described later). On the other hand, when any one of the electrothermal sheets 13 is disconnected, the portion cannot be heated and temperature unevenness occurs in the short term.

On the other hand, since the heat from the other electrothermal sheet 13 is transmitted to the non-heat-equivalent portion through the inner steel plate 11 and the convection layer 15, the temperature unevenness is eliminated. That is, due to the synergistic effect of the convection layer and the electrical parallel, heating can be continued even when there is a partial break.

-Additional composition and effect-
In this embodiment, the electrothermal sheet 13 is electrically arranged in parallel in each constituent member and each region. Thereby, the preset temperature of each electric heating sheet 13 can be individually set.

・ Case 1
The asphalt mixture is put into the hopper 6 and conveyed by the bar feeder 7. With the time from upstream to downstream, the temperature of the asphalt mixture tends to drop. Therefore, it is preferable that the preheat imparting function is higher toward the downstream.

For example, the set temperature of the upper side 61 of the hopper and the hopper rear surface 63 is set to 80 degrees, and the set temperature of the lower side 62 and the front wing 9 is set to 90 degrees. Further, the set temperature of the bar feeder 7 is set to 95 degrees.

Thereby, a sufficient preheating effect can be obtained even on the downstream side.

・ Case 2
The generally L-shaped corner portion 64 tends to accumulate asphalt mixture during storage. As the temperature of the asphalt mixture drops, it clumps and clumps. When this lump is mixed with a normal asphalt mixture, pavement quality deteriorates, which is not preferable.

On the other hand, for example, the set temperature of the upper side 61 of the hopper is set to 80 degrees and the set temperature of the lower side 62 of the hopper is set to 90 degrees, while only the region closest to the corner 64 of the upper hopper side 61 and the lower side 62 is set. The temperature is 100 degrees. That is, the set temperature closest to the corner 64 is set to be equal to or higher than the set temperature of the other region.

This makes it difficult for the asphalt mixture to clump at the corner 64, thus ensuring pavement quality.

DESCRIPTION OF SYMBOLS 1 Crawler 2 Driver's seat 3 Asphalt mixture insertion part 4 Screw spreader 5 Screed 6 Hopper 7 Bar feeder 8 Rear plate 9 Front wing 10 Heating device 11 Inner steel plate 12 Outer steel plate 13 Electric heating sheet 14 Heat insulation sheet 15 Convective layer 16 Temperature sensor 17 Control Device 18 Outside air sensor 61 Upper side of hopper wing side 62 Lower side of hopper wing side 63 Hopper rear surface 71 Bottom plate 72 Rotating part

Claims (7)

Equipped with a heating device to heat the asphalt mixture input part of the asphalt finisher,
The heating device
Constituting a part of the asphalt mixture charging part, opposite inner plate member and outer plate member,
An asphalt finisher comprising: a planar electric heating device in close contact with the inner side of the inner plate member. The asphalt mixture charging part is composed of hopper wing upper stage, hopper wing lower stage, hopper rear surface, front wing, rear plate, and bar feeder.
The asphalt finisher according to claim 1, wherein the heating device is provided in one or more of the components. A plurality of the planar electric heating devices are provided,
The asphalt finisher according to claim 1 or 2, wherein the plurality of planar electric heating devices are electrically in parallel. In the plurality of planar electric heating devices,
The asphalt finisher according to claim 3, wherein the set temperature of the planar electric heating device provided at the lower position is set to be equal to or higher than the set temperature of the planar electric heating device provided at the upper position. In the plurality of planar electric heating devices,
The set temperature of the planar electric heating device provided in the lower hopper wing is set so as to be equal to or higher than the set temperature of the planar electric heating device provided in the upper hopper wing of the asphalt mixture charging unit. Asphalt finisher as described. A corner portion is formed in a continuous portion between the upper hopper wing and the lower hopper wing of the asphalt mixture charging portion,
A plurality of planar electric heating devices are provided on the upper hopper wing and / or the lower hopper wing,
4. The plurality of planar electric heating devices are set such that a set temperature of the planar electric heating device closest to the corner is equal to or higher than a setting temperature of another planar electric heating device. Asphalt finisher. The heating device is
A heat insulating sheet in close contact with the inside of the outer plate member;
The asphalt finisher according to any one of claims 1 to 6, further comprising a convection layer provided between the planar electric heating device and the heat insulating sheet.

Images