JP7033296B2 - Screed equipment and road paving machines - Google Patents

Description

The present invention relates to a screed device used in a road paving machine, and more specifically to a screed device capable of heating a screed plate by electricity.

Patent Document 1 discloses a screed device that heats a screed plate using a sheathed heater. In the screed device described in Patent Document 1, the seeds heater is brazed to the steel member, and then the steel member and the screed plate are welded by intermittent welding or spot welding of fillet welding. This makes it possible to provide a screed device having excellent heating energy transfer efficiency and heating uniformity without losing wear resistance.

The sheathed heater is an electric heater that heats by utilizing Joule heat generated in a conductor through which an electric current flows. The sheathed heater has a structure in which a heating element such as a nichrome wire is covered with an insulator.

Patent Document 2 describes a screed device provided with a high-frequency induction heating mechanism in which a high-frequency induction coil is arranged and fixed on the upper surface of the screed plate, a high-frequency current is passed through the high-frequency induction coil, and the screed plate is heated by the generated Joule heat. It has been disclosed. In this way, by taking a means of inducing and heating the plate by passing a high-frequency current through the high-frequency induction coil and using the generated Joule heat, the entire surface of the plate, which is the heating material, is uniformly and accurately applied, in an extremely short time, and moreover. It is said that the bottom surface of the plate can be efficiently heated to a predetermined temperature by the skin effect of the eddy current. In paragraph 0009 of Patent Document 2, it is stated that a holding member made of, for example, a ceramic, which is a heat-resistant insulator, is mounted at a predetermined position on the upper part of the high-frequency induction coil.

Patent Document 3 discloses a screed device capable of uniformly heating the screed plate by inserting a heat conductive plate between the electric heating unit and the screed plate. In Patent Document 3, it is said that a coil is wound in a rigid hollow bar as an electric heating unit (paragraph 0028 of Patent Document 3). Further, in paragraph 0028 of Patent Document 3, an insulating layer is provided on the electric heating portion so that heat flows downward into the heat conductive plate, whereby the heat is spread over the entire heat conductive plate. It is said that the heat spreads relatively evenly.

Japanese Unexamined Patent Publication No. 2012-7466 Japanese Unexamined Patent Publication No. 10-252012 Special Table 2003-591733 Gazette

Patent Document 1 proposes a structure for heating a screed plate using a sheathed heater. Although Patent Document 1 refers to the joining method and arrangement shape of the sheathed heater, it discloses a technique for efficiently transferring the heat generated by the sheathed heater to the screed plate without leaking to the outside. It has not been. In the structure described in Patent Document 1, the upper side of the sheathed heater is not insulated at all. Therefore, in such a structure, the thermal efficiency has to be lowered.

The screed device described in Patent Document 2 uses a heating structure using a high-frequency induction coil, and discloses that a ceramic holding member, which is a heat-resistant insulator, is used above the high-frequency induction coil.

In the screed device described in Patent Document 3, an electric heating unit using a coil is used, and a structure that uniformly spreads heat over the entire heat conductive plate is adopted by providing an insulating layer on the electric heating unit. Has been done.

However, when a sheathed heater is used, the problem is how to fix the sheathed heater to the screed plate. Since the screed plate vibrates up and down during pavement, the sheathed heater must be fixed to the screed plate with a structure that can withstand the vibration. Therefore, a structure such as the screed device described in Patent Document 2 having a heat-resistant insulator and the screed device described in Patent Document 3 having an insulating layer is used as it is for a screed device that heats a screed plate with a sheathed heater. Cannot be applied.

Therefore, an object of the present invention is to provide a screed device having a structure capable of increasing the thermal efficiency as much as possible when the screed plate is heated by using a sheathed heater, and a road paving machine using the screed device.

In order to solve the above problems, the present invention has the following features. The present invention is a screed device used in a road paving machine, in which the screed plate is in contact with the upper surface of the screed plate, and at least two sheathed heaters arranged in the width direction of the road paving machine and a plate shape. The sheathed heater is put in the recess provided in the rib portion, and at least two sheathed heaters are pressed together against the screed plate by the thick portion of the recess , and each is arranged at a space. A metal heat shield plate that is placed on multiple holding parts and on top of multiple holding parts and is not in direct contact with at least two sheathed heaters blocks heat radiation upward from the sheathed heater. It has a hot part.

Preferably, the sheathed heater is pressed by a plurality of pressing portions arranged in parallel.

Further, the present invention is a screed device used in a road paving machine, which comprises a screed plate, a seeds heater arranged to heat the screed plate, a holding portion for pressing the seeds heater against the screed plate, and a seeds heater. It is equipped with a heat shield that blocks upward heat dissipation and a drainage means for draining water around the sheathed heater to the outside. The drainage means is between the screed plate and the main frame of the screed device. It is characterized by being a hole provided in the arranged member.

Preferably, a cover for preventing the hole from being clogged may be further provided.

The present invention is a road paving machine provided with the screed device.

According to the present invention, a holding portion for pressing the sheathed heater against the screed plate is provided. Therefore, even if the seeds heater is deformed when the seeds heater is heated, the seeds heater is pressed against the screed plate, so that the screed plate can be efficiently heated.

Further, according to the present invention, a heat shield portion for blocking heat radiation to the upper side of the sheathed heater is provided. Therefore, it is possible to efficiently heat the screed plate because the heat of the sheathed heater is prevented from being dissipated upward.

There are various possible shapes of the presser portion. For example, by providing the presser portion with a recess for inserting the sheathed heater, the sheathed heater can be efficiently pressed with a simple structure.

At that time, if a rib portion is provided on the bottom surface of the pressing portion and a recess is provided in the rib portion, the sheathed heater can be pressed while maintaining the strength of the pressing portion.

By arranging a plurality of pressing portions in parallel, it is possible to press the sheathed heater with an even force.

By using a metal heat shield plate as the heat shield, not only is it easy to process, but it is also possible to effectively block heat dissipation. In addition, there is a problem that the heat insulating effect is reduced when water is contained, but when a metal heat insulating plate is used, the heat insulating effect due to water is hardly reduced as is caused by the heat insulating material of the fiber. , Effective heat insulation can be realized.

By arranging the heat shield plate on the holding portion, it is possible to hold down the sheathed heater and to realize heat shielding at the same time. Further, since the heat of the holding portion can be prevented from being dissipated upward, the heating efficiency is improved by arranging the heat shield plate on the holding portion.

By using the drainage means, when water enters the screed device, it is possible to prevent the heat from being taken away due to the evaporation of the water as much as possible. Therefore, it can be said that the heating efficiency is improved by providing the drainage means.

As a drainage means, it can be realized with a simple structure such as a hole provided in a member, and the heating efficiency can be improved at low cost without adopting a special structure for draining water. Can be done.

By providing the hole cover, it is possible to prevent the hole from being clogged with foreign matter, and it is possible to maintain the water draining action during construction.

These and other objects, features, aspects and effects of the present invention will be further clarified from the following detailed description in light of the accompanying drawings.

FIG. 1 is an external perspective view of the road paving machine 1 according to the embodiment of the present invention when viewed from diagonally above from the left rear. FIG. 2 is an external perspective view of the road pavement machine 1 when viewed from the bottom surface side. FIG. 3 is a perspective view showing the external structure of the main screed 7a, the left telescopic screed 7b, and the right telescopic screed 7c provided in the screed device 7. FIG. 4 is a perspective view showing the internal structure of the screed 7a when the main frame 10 is removed. FIG. 5A is an exploded perspective view showing the internal structure of the screed 7a. FIG. 5B is an exploded perspective view showing the internal structure of the screed 7a. FIG. 5C is a perspective view of the pressing member 15 when viewed from the bottom surface side. FIG. 6 is a cross-sectional view when cut along the line AA in FIG. 4, and is a cross-sectional view in a state where the main frame 10 is attached. FIG. 7 is a cross-sectional view taken along the line BB in FIG. 4, and is a cross-sectional view in a state where the main frame 10 is attached. FIG. 8 is a cross-sectional view showing an example of a structure for preventing the hole 17a for draining water from being clogged.

FIG. 1 is an external perspective view of the road paving machine 1 according to the embodiment of the present invention when viewed from diagonally above from the left rear. FIG. 2 is an external perspective view of the road pavement machine 1 when viewed from the bottom surface side.

In FIGS. 1 and 2, the road paving machine 1 includes a vehicle body 2, a hopper 3, a front wheel 4, a conveyor 5, a screw 6, a screed device 7, a leveling arm 8, and a rear wheel 9. In the road paving machine 1, the hopper 3 side is in the forward traveling direction. The hopper 3 accommodates an asphalt mixture supplied from a dump truck or the like (not shown). The asphalt mixture in the hopper 3 is conveyed in front of the screed 7 by a conveyor 5 provided inside the vehicle body 2. The screw 6 spreads the conveyed asphalt mixture to the left and right in the traveling direction. The asphalt mixture spread and stretched by the screw 6 is spread and leveled by the screed device 7. The leveling arm 8 adjusts the height of the screed device 7 to smoothly spread the asphalt mixture.

The screed device 7 includes a main screed 7a, a left telescopic screed 7b that can be expanded and contracted to the left and right, and a right telescopic screed 7c that can also be expanded and contracted to the left and right. As the structure for expanding and contracting the telescopic screeds 7b and 7c, any well-known structure can be used.

Here, the screed device 7 using the main screed 7a, the left telescopic screed 7b, and the right telescopic screed 7c is illustrated, but this is only an example. The present invention is also applicable to a screed device not provided with a telescopic screed, and the presence or absence of a telescopic screed does not limit the present invention.

FIG. 3 is a perspective view showing the external structure of the main screed 7a, the left telescopic screed 7b, and the right telescopic screed 7c provided in the screed device 7. In describing the structure, it is not necessary to consider the difference in size between the main screed 7a, the left telescopic screed 7b, and the right telescopic screed 7c. The structure shall be explained. Further, in the main screed 7a, the left telescopic screed 7b, and the right telescopic screed 7c, since the parts related to the present invention have the same structure, they will be described below as representatives as screed 7a.

FIG. 4 is a perspective view showing the internal structure of the screed 7a when the main frame 10 is removed. 5A and 5B are exploded perspective views showing the internal structure of the screed 7a. FIG. 5C is a perspective view of the pressing member 15 when viewed from the bottom surface side. FIG. 6 is a cross-sectional view when cut along the line AA in FIG. 4, and is a cross-sectional view in a state where the main frame 10 is attached. FIG. 7 is a cross-sectional view taken along the line BB in FIG. 4, and is a cross-sectional view in a state where the main frame 10 is attached.

The screed 7a includes a main frame 10, a screed plate 11, a sheathed heater 12, a tip member 13, a mounting member 14, a pressing member 15, a heat shield member 16, and a mounting member 17.

The screed 7a has a screed plate 11 on the bottom surface. The screed plate 11 is provided with a plurality of fastening elements such as stud bolts that project in a columnar shape. The fastening element is fixed by welding or the like. The screed plate 11 is attached to the lower part of the main frame 10 via the attachment member 14 on the front side and the attachment member 17 on the rear side. The nuts and the like fixed to the fastening element are not shown. The mounting member 14 and the mounting member 17 are merely spacers arranged between the screed plate 11 and the main frame 10, other than considering that the screed plate 11 is provided for mounting the screed plate 11 on the main frame 10. It can be said that it is a member of. Therefore, the mounting member 14 and the mounting member 17 can be understood simply as members arranged between the screed plate 11 and the main frame 10 without being bound by the expression “mounting member”.

One or more sheathed heaters 12 are arranged on the upper surface of the screed plate 11. The arrangement position, number, shape, etc. of the sheathed heater 12 are not particularly limited, and are appropriately designed. By devising the arrangement position, number, shape, etc. of the sheathed heater 12, it is possible to heat a place where heating is difficult. The sheathed heater 12 arranged on the screed plate 11 is pressed so as not to move by the pressing member 15.

The cross-sectional shape of the sheathed heater 12 is not limited to a circle, but may be a triangle, a quadrangle, or another polygon, and the shape is not limited to the present invention.

The pressing member 15 is a member for pressing the sheathed heater 12 against the screed plate 11. The pressing member 15 is provided with a hole at a position corresponding to the fastening element. Further, the pressing member 15 has a rib portion 15b on the bottom surface side, and the rib portion 15b is formed with one or more recesses 15a matching the cross-sectional shape of the sheathed heater 12. By inserting the sheathed heater 12 into the recess 15a, the sheathed heater 12 is pressed against the screed plate 11.

A plurality of pressing members 15 are arranged in parallel. As a result, the sheathed heater can be pressed down with a uniform force.

The front mounting member 14 is provided with a recess 14a according to the shape of the pressing member 15.

The heat shield member 16 is arranged on the holding member 15. The heat shield member 16 is provided with a hole at a position corresponding to the fastening element. In FIG. 5B, the fastening correspondence of the fastening element, the hole of the holding member 15, and the hole of the heat shield member 16 is shown by a alternate long and short dash line.

The heat shield member 16 is fixed to the fastening element of the screed plate 11. As a result, the sheathed heater 12 is pressed against the screed plate 11 by the heat shield member 16 and the pressing member 15. The recess 15a provided in the pressing member 15 prevents the sheathed heater from shifting.

The sheathed heater 12 expands and contracts and its shape changes depending on the heating temperature. Therefore, as described in Patent Document 1, if the sheathed heater 12 is simply attached to the screed plate 11 or the steel plate by brazing or welding, the sheathed heater in the unbonded portion is deformed and the screed plate 11 is formed. There is a possibility that the contact will not be achieved, and the heating efficiency will drop.

However, if the pressing member 15 is used, even if the sheathed heater is deformed, the sheathed heater 12 can be pressed against the screed plate 11 as a whole, so that it is possible to prevent the heating efficiency from dropping.

Even if the sheathed heater 12 is fixed to the screed plate 11 directly or via a steel plate, the pressing member 15 exerts a pressing action. Therefore, in the present invention, the sheathed heater 12 is the screed plate 11. In addition, it is not excluded that the steel plate is directly fixed by brazing or the like, or that the steel plate is fixed to the screed plate 11 by welding or the like after being fixed to the steel plate by brazing or the like.

The heat shield member 16 is made by processing a metal heat shield plate having a heat shield effect (for example, SPHC (hot rolled steel plate) or the like). For example, the heat shield member 16 may have an SPHC thickness of 1.6 mm or the like, but is not limited to this as long as it is a member having a heat shield effect. By using the heat shield member 16, it is possible to block and suppress the heat radiation upward, so that the heating efficiency is improved. It is preferable to use a metal heat shield plate as the heat shield member, but as the heat shield member 16, a heat insulating material woven with fibers may be used. However, when the heat insulating material is used as the heat shield member 16, if it contains water, the heating efficiency may be lower than that of the metal heat shield plate. In addition, a ceramic heat shield plate may be used for the heat shield member 16.

By pressing the sheathed heater 12 from above with the pressing member 15 in this way, even if the sheathed heater 12 is deformed by heating, the sheathed heater 12 is pressed against the screed plate 11, so that the screed plate 11 can be heated. It will be done efficiently.

Further, by arranging the heat shield member 16 on the holding member 15, it is possible to block and suppress the heat radiation upward, so that the screed plate 11 can be heated more efficiently. ..

If a metal heat shield plate is used as the heat shield member 16, the heating efficiency is further improved.

According to the embodiment of the present invention, it is possible to provide a screed device having high heating efficiency while using a sheathed heater.

Water may enter the screed 7a due to its structure. For example, rainwater may enter. In addition, water may enter when the car is washed for maintenance. When water enters the screed 7a, heat is taken away until the water evaporates, and the heating efficiency is lowered. When heating with a gas burner, water evaporates quickly, so it was rarely necessary to consider the heating efficiency when water enters the screed, but when heating the screed plate with electrical energy, , The influence of water cannot be ignored.

Therefore, in the screed 7a using electric heating, it is necessary to discharge water to the outside as soon as possible.

Therefore, in the embodiment of the present invention, one or more holes 17a for draining water are provided in the rear mounting member 17. The holes 17a allow the water existing around the sheathed heater 12 to go out, and it is possible to prevent the heat from being taken away by the time the water evaporates. However, in the present invention, the drainage hole 17a is merely a mechanism for further improving the heating efficiency, and is not an essential configuration.

Here, the hole 17a has a semicircular columnar shape, but the shape thereof is not particularly limited, such as a square columnar shape or a triangular columnar shape.

If a foreign substance enters the hole 17a during the work, the water cannot be discharged. Therefore, it is advisable to devise the shape of the main frame 10 so that foreign matter does not enter the hole 17a. For example, it is preferable that the main frame 10 has a structure in which water can be discharged to the outside through the gap of the main frame 10 while closing the holes 17a.

FIG. 8 is a cross-sectional view showing an example of a structure for preventing the hole 17a for draining water from being clogged. As shown in FIG. 8, the cover 18 is detachably attached to the main frame 10 so that the holes 17a are not clogged with foreign substances such as asphalt mixture and gravel. By providing the gap 18a between the cover 18 and the screed plate 11, water will flow from the gap 18a. The oil content of the asphalt mixture can be cleaned by removing the cover 18 from the oil content in the gap 18a between the cover 18 and the screed plate 11.

It should be noted that, without providing a gap between the cover 18 and the screed plate 11, a gap is provided between the cover 18 and the mounting member 17, and holes and recesses are appropriately provided in the cover 18 to drain water. Means may be secured.

In the above embodiment, the pressing member 15 and the heat shield member 16 are separate members, but a rib is provided on the bottom surface of the heat shield member, and a recess for inserting the sheathed heater 12 into the rib. It is possible to use the heat shield member as a holding member by providing the above. Therefore, in the present invention, the pressing member and the heat shielding member may be integrated. In that case, functionally, it can be said that a holding portion for holding the sheathed heater and a heat shielding portion for blocking upward heat dissipation are provided in the screed device.

In the above embodiment, the heat shield member 16 is a single plate-shaped member, but the heat shield member may be formed by a plurality of plate-shaped members.

In the above embodiment, the pressing member 15 is composed of a plurality of members, but a plurality of ribs arranged in parallel to the bottom surface of one plate-shaped member are provided, and the ribs are provided with seeds. By providing a recess that matches the shape of the heater, it is possible to use a single plate-shaped member as a holding member. In this case, one plate-shaped member can be regarded as functioning as a holding portion, and each rib and recess can be regarded as functioning as a holding portion.

As described above, in the present invention, it is preferable to provide a pressing portion for pressing the sheathed heater against the screed plate and a heat shielding portion for blocking the heat of the sheathed heater.

In the above embodiment, the mounting member 17 for mounting the main frame 10 on the screed plate 11 is a single member, but it may be divided into a plurality of members. That is, the main frame 10 may be attached to the screed plate 11 via a plurality of attachment members. Even in that case, it is preferable that each mounting member is formed with a hole for draining water.

In the above embodiment, the mounting member 17 is used as the mounting portion for mounting the main frame 10 on the screed plate 11. However, in the case of a structure in which the main frame 10 can be directly mounted on the screed plate 11, the main frame 10 is used. It is preferable that the frame 10 is formed with a hole for draining water.

That is, it can be said that the screed device of the present embodiment is provided with a drainage means for draining the water around the sheathed heater to the outside. In the illustrated example, the draining means is the hole 17a provided in the mounting member 17. Further, if the drainage is realized by providing the drainage hole in the main frame 10, the hole provided in the main frame 10 is the drainage means. In addition, any means for draining water around the sheathed heater to the outside falls under the drainage means of the present invention.

Although the present invention has been described in detail above, the above description is merely an example of the present invention in all respects and does not intend to limit the scope thereof. Needless to say, various improvements and modifications can be made without departing from the scope of the present invention.

The present invention relates to a screed device and is industrially applicable.

1 Road paving machine 2 Body 3 Hopper 4 Front wheel 5 Conveyor 6 Screw 7 Screed device 7a Main screed 7b Left telescopic screed 7c Right telescopic screed 8 Leveling arm 9 Rear wheel 10 Main frame 11 Screed plate 12 Seeds heater 13 Tip member 14 Mounting member 14a Recess 15 Recess member 15a Recess 15b Rib 16 Heat shield member 17 Mounting member 17a Hole (drainage means)

Claims (5)

A screed device used in road paving machines.
With the screed plate,
At least two sheathed heaters that are in contact with the upper surface of the screed plate and are arranged in the width direction of the road paving machine.
It has a plate-shaped rib portion, and the sheathed heater is placed in a recess provided in the rib portion, and at least two sheathed heaters are pressed together against the screed plate by the thick portion of the recess. With multiple holding parts arranged at intervals,
A heat shield that is arranged on the plurality of holding portions and that blocks heat radiation upward from the sheath heater by a metal heat shield plate that is not in direct contact with at least the two sheath heaters. A screed device characterized by being provided. The screed device according to claim 1 , wherein the plurality of holding portions are arranged in parallel. A screed device used in road paving machines.
With the screed plate,
A sheathed heater arranged to heat the screed plate, and
A holding portion that presses the sheathed heater against the screed plate, and
A heat shield that blocks heat dissipation above the sheathed heater,
A drainage means for draining the water around the sheathed heater to the outside is provided.
The screed device is characterized in that the draining means is a hole provided in a member arranged between the screed plate and the main frame of the screed device. The screed device according to claim 3, further comprising a cover for preventing the holes from being clogged. A road paving machine comprising the screed device according to any one of claims 1 to 4.

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