JP2019082004A - Screed device and road paving machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screed device having a structure capable of increasing the thermal efficiency as much as possible when heating a screed plate using a sheathed heater, and a road paving machine using the screed device. SOLUTION: A screed device 7a includes a screed plate 11, a sheathed heater 12 arranged to heat the screed plate 11, a plurality of pressing members 15 for pressing the seeds heater 12 against the screed plate 11, and a sheathed heater 12. It is provided with a heat shield member 16 that blocks heat radiation upward. The mounting member 17 arranged between the screed plate 11 and the main frame 10 has a hole 17a for draining water. As a result, the sheathed heater 12 is pressed against the screed plate 11 and the heat radiation upward is blocked, so that the heating efficiency is improved. Further, since water escapes to the outside of the screed device 7a, heat is prevented from being taken away due to evaporation of water, so that the heating efficiency is further improved. [Selection diagram] FIG. 4

Description

  The present invention relates to a screed device used in a road paver, and more particularly to a screed device capable of electrically heating a screed plate.

  Patent Document 1 discloses a screed apparatus which heats a screed plate using a sheathed heater. In the screed device described in Patent Document 1, after the sheathed heater is brazed to the steel member, the steel member and the screed plate are welded by fillet welding or spot welding. It is said that this makes it possible to provide a screed device excellent in 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 current flows. The sheathed heater has a configuration in which a heating element such as a nichrome wire is covered with an insulator.

  Patent Document 2 discloses a screed apparatus including a high-frequency induction heating mechanism in which a high-frequency induction coil is disposed on and fixed to the upper surface of a screed plate and a high-frequency current is supplied to the high-frequency induction coil to heat the screed plate by generated Joule heat. It is disclosed. As described above, by supplying a high frequency current to the high frequency induction coil and taking a means for inductively heating the plate by generated Joule heat, the entire surface of the plate which is the heating material is uniformly and precisely in a very short time. 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, a pressing member made of, for example, a ceramic, which is a heat-resistant insulator, is placed at a predetermined position on the upper part of the high frequency induction coil.

  Patent Document 3 discloses a screed apparatus capable of uniformly heating a screed plate by inserting a heat conduction type plate between an electric heating portion and the screed plate. In Patent Document 3, 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 the heat flows downward into the heat conductive plate, thereby covering the entire heat conductive plate, It is believed that the heat spreads relatively uniformly.

JP, 2012-7466, A Japanese Patent Application Laid-Open No. 10-252012 Japanese Patent Publication No. 2003-519733

  In patent document 1, it is proposed about the structure which heats a screed plate using a sheathed heater. Patent Document 1 mentions a bonding method and an arrangement shape of a sheathed heater, but discloses a technique for efficiently transmitting heat generated by the sheathed heater to a screed plate without leaking it to the outside. It has not been. In the structure described in Patent Document 1, the upper side of the sheathed heater is not thermally insulated at all. Therefore, in such a structure, the thermal efficiency can not but be reduced.

  In the screed device described in Patent Document 2, a heating structure by a high frequency induction coil is used, and it is disclosed that a pressing member made of ceramic, 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 by providing an insulating layer on the electric heating unit, a structure is adopted in which heat is uniformly spread over the entire heat conductive plate. It is done.

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

  Therefore, when heating a screed plate using a sheathed heater, the present invention aims at providing a screed device which has a structure which can raise thermal efficiency as much as possible, and a road paving machine using the same.

  In order to solve the above-mentioned subject, the present invention has the following features. The present invention is a screed apparatus for use in a road paver, comprising a screed plate, a sheathed heater arranged to heat the screed plate, a pressing portion for pressing the sheathed heater against the screed plate, and upward of the sheathed heater. And a heat shield to block the heat radiation of the

  Preferably, the pressing portion may have a recess in which the sheathed heater is inserted.

  Preferably, the pressing portion is provided with a recess in the rib portion on the bottom surface.

  Preferably, the sheathed heater may be held down by a plurality of holding portions arranged in parallel.

  Preferably, the heat shield may be made of a metal heat shield plate.

  Preferably, the heat shield may be disposed on the pressing portion.

  Preferably, a water draining means for draining water around the sheathed heater may be further provided.

  For example, the drainage means may be holes provided in a member disposed between the screed plate and the main frame of the screed device.

  Preferably, a cover may be further provided to prevent the holes from being clogged.

  The present invention is a road pavement machine provided with the above-mentioned screed device.

  According to the present invention, the pressing portion for pressing the sheathed heater against the screed plate is provided. Therefore, even if the sheathed heater is deformed at the time of heating the sheathed heater, the sheathed heater is held down on the screed plate, so that the screed plate can be efficiently heated.

  Further, according to the present invention, the heat shield is provided to block the heat radiation to the upper side of the sheath heater. Therefore, the heat of the sheathed heater is prevented from being dissipated upward, so that the screed plate can be efficiently heated.

  Although various shapes are considered as a shape of a holding | suppressing part, it becomes possible to suppress a sheathed heater efficiently by simple structure, for example by providing the recessed part which puts a sheathed heater in a holding | suppressing part.

  At that time, if the rib portion is provided on the bottom surface of the pressing portion and the recess portion is provided on 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 equal force.

  By using a metal heat shield as the heat shield, not only processing is easy, but also heat radiation can be effectively cut off. In addition, there is a problem that the heat insulation effect is reduced when it contains water, but when using a metal heat shield plate, the decrease of the heat shield effect by water that occurs with the heat insulation material of fiber hardly occurs. Effective heat shielding can be realized.

  By disposing the heat shield plate on the pressing portion, it is possible to realize pressing of the sheathed heater and heat shielding simultaneously. In addition, since the heat of the pressing portion can be prevented from radiating to the upper side, the heating efficiency is improved by arranging the heat shield plate on the pressing portion.

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

  As a drainage means, for example, it can be realized with a simple structure like a hole provided in a member, and the heating efficiency can be enhanced at low cost without adopting a special structure for drainage. Can.

  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 drainage action during construction.

  These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

FIG. 1 is an external perspective view of a road pavement machine 1 according to an embodiment of the present invention as viewed from diagonally above from the rear left. FIG. 2 is an external perspective view of the road paver 1 as viewed from the bottom side. FIG. 3 is a perspective view showing the external appearance of the main screed 7a, the left stretchable screed 7b, and the right stretchable screed 7c provided in the screed device 7. As shown in FIG. FIG. 4 is a perspective view showing an internal structure when the main frame 10 is removed in the screed 7a. 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 when the pressing member 15 is viewed from the bottom side. FIG. 6 is a cross-sectional view taken along the line A-A in FIG. 4 and is a cross-sectional view of a state in which the main frame 10 is attached. FIG. 7 is a cross-sectional view taken along the line B-B in FIG. 4 and is a cross-sectional view of a state in which the main frame 10 is attached. FIG. 8 is a cross-sectional view showing an example of a structure for preventing clogging of the drainage holes 17a.

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

  In FIG. 1 and FIG. 2, the road pavement machine 1 includes a vehicle body 2, a hopper 3, a front wheel 4, a conveyor 5, a screw 6, a scredding device 7, a leveling arm 8 and a rear wheel 9. In the road paver 1, the hopper 3 side is in the forward traveling direction. The hopper 3 accommodates the 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 left and right in the traveling direction. The asphalt mixture spread by the screw 6 is spread by the screed device 7. The leveling arm 8 adjusts the height of the screed device 7 and smoothly lays out the asphalt mixture.

  The screed device 7 is provided with a main screed 7a, a left telescopic screed 7b that can expand and contract in the left and right direction, and a right telescopic screed 7c that can expand and contract in the left and right direction as well. In addition, as a structure for expanding and contracting the telescopic screed 7b and 7c, any known structure can be used.

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

  FIG. 3 is a perspective view showing the external appearance of the main screed 7a, the left stretchable screed 7b, and the right stretchable screed 7c provided in the screed device 7. As shown in FIG. In describing the structure, it is not necessary to consider the differences in the sizes of the main screed 7a, the left telescopic screed 7b, and the right telescopic screed 7c, and therefore, representatively referring to FIGS. Let us explain the structure. Further, in the main screed 7a, the left telescopic screed 7b, and the right telescopic screed 7c, portions relating to the present invention have the same structure, and therefore, will be representatively described as the screed 7a hereinafter.

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

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

  The screed 7 a has a screed plate 11 on the bottom surface. The screed plate 11 is provided with a plurality of cylindrically projecting fastening elements such as stud bolts. 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 front side mounting member 14 and the rear side mounting member 17. About a nut etc. which are fixed to a fastening element, illustration is omitted. The attachment member 14 and the attachment member 17 are simply used as a spacer disposed between the screed plate 11 and the main frame 10, except that the screed plate 11 is considered to be attached to the main frame 10. It can be said that it is a member of Therefore, the attachment member 14 and the attachment member 17 can be understood simply as a member disposed between the screed plate 11 and the main frame 10 without being bound by the expression “attachment member”.

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

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

  The pressing member 15 is a member for pressing the sheathed heater 12 against the screed plate 11. The holding member 15 is provided with a hole at a position corresponding to the fastening element. Furthermore, the pressing member 15 has a rib portion 15 b on the bottom surface side, and the rib portion 15 b is formed with one or more concave portions 15 a that match the cross-sectional shape of the sheathed heater 12. The sheathed heater 12 is pressed against the screed plate 11 by putting the sheathed heater 12 in the recess 15 a.

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

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

  The heat shield member 16 is disposed on the pressing member 15. The heat shield member 16 is provided with holes at locations corresponding to the fastening elements. In FIG. 5B, the fastening correspondence of the fastening element, the hole of the pressing member 15, and the hole of the heat shield member 16 is indicated by an alternate long and short dash line.

  The heat shield 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 15 a provided in the pressing member 15 prevents the sheath heater from being displaced.

  The sheathed heater 12 stretches or changes its shape according to the heating temperature. Therefore, as described in Patent Document 1, only by attaching the sheathed heater 12 to the screed plate 11 or steel plate by brazing, welding or the like, the sheathed heater in a portion not joined is deformed and the screed plate 11 And may not be in close contact with each other, resulting in a decrease in heating efficiency.

  However, if the pressing member 15 is used, the sheathed heater 12 can be entirely pressed against the screed plate 11 even if the sheathed heater is deformed, so that the heating efficiency can be prevented from being lowered.

  In addition, even if the sheathed heater 12 is fixed to the screed plate 11 directly or through a steel plate, the pressing action by the pressing member 15 is generated, so in the present invention, the sheathed heater 12 is a screed plate 11. It is not excluded that the steel plate is fixed to the screed plate 11 by welding or the like after being fixed directly by brazing or fixed to the steel plate by brazing or the like.

  The heat shield member 16 is obtained by processing a metal heat shield plate (for example, SPHC (hot-rolled steel plate) or the like) having a heat shield effect. For example, although the thickness 1.6 mm of SPHC etc. can be considered as the heat shielding member 16, if it is a member which has a heat shielding effect, it will not be limited to this. By using the heat shield member 16, the heat radiation to the upper side can be shut off and suppressed, so the heating efficiency is enhanced. In addition, although it is preferable to use a metal heat shield board as a heat shield member, as the heat shield member 16, the heat insulating material in which the fiber was woven may be used. However, in the case where the heat insulating material is used as the heat shield member 16, if it contains water, there is a possibility that the heating efficiency may be reduced compared to a metal heat shield plate. In addition, a heat shield made of ceramic may be used as the heat shield 16.

  As described above, by pressing the sheathed heater 12 from above with the pressing member 15, even if the sheathed heater 12 is deformed by heating, the sheathed heater 12 is pressed against the screed plate 11, so that heating of the screed plate 11 is achieved. It will be done efficiently.

  Further, by disposing the heat shield member 16 on the pressing member 15, the heat radiation to the upper side can be blocked and suppressed, and furthermore, the heating of the screed plate 11 can be efficiently performed. .

  Then, 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 with high heating efficiency while using a sheathed heater.

  Water may enter the screed 7a due to its structure. For example, rainwater etc. enter. In addition, water may enter at the time of car wash of maintenance. When water enters the screed 7a, heat is taken until the water is evaporated, and the heating efficiency is reduced. When heating with a gas burner, the evaporation of water is fast, so it is hardly necessary to consider the heating efficiency when water enters the screed, but when heating the screed plate with electrical energy , The impact of water can not be ignored.

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

  Therefore, in the embodiment of the present invention, one or more holes 17 a for draining water are provided in the rear attachment member 17. The holes 17a allow the water present around the sheathed heater 12 to be discharged to the outside, and it is possible to prevent the heat from being taken away until the water evaporates as much as possible. However, in the present invention, the holes 17a for draining water are merely mechanisms for further improving the heating efficiency, and are not essential components.

  In addition, although the hole 17a is made into a semi-cylindrical shape here, the shape in particular, such as square-pole shape and triangular-pole shape, is not limited.

  In the meantime, if foreign matter enters the hole 17a during the operation, the water can not be discharged. Therefore, it is preferable to devise the shape of the main frame 10 so that foreign matter does not enter the holes 17a. For example, the main frame 10 may be configured to be capable of discharging water to the outside through the gaps of the main frame 10 while closing the holes 17 a.

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

  In addition, a gap is provided between the cover 18 and the mounting member 17 without providing a gap between the cover 18 and the screed plate 11, and a hole or a recess is appropriately provided in the cover 18, thereby removing water. Means may be secured.

  In the above embodiment, although the pressing member 15 and the heat shielding member 16 are separate members, a rib is provided on the bottom surface of the heat shielding member, and a recess for putting the sheathed heater 12 in the rib It is possible to make the heat shield member double as a pressing member by providing 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 the pressing unit for pressing the sheathed heater and the heat shield unit for blocking the heat radiation upward are provided in the screed device.

  In the said embodiment, although the heat shield member 16 was a plate-shaped member of 1 sheet, the heat shield part may be comprised by the plate-shaped member of several sheets.

  In the above embodiment, although the pressing member 15 is configured by a plurality of members, a plurality of ribs disposed in parallel to the bottom surface of a single plate-like member are provided, and It is also possible to use a single plate-like member as a pressing member by providing a recess that matches the shape of the heater. In this case, one plate-like member can be regarded as functioning as a pressing portion, and it can also be understood that each rib and the recess respectively function as pressing portions.

  As described above, in the present invention, it is preferable that a pressing portion that presses the sheathed heater against the screed plate and a heat shield that shields the heat of the sheathed heater be provided.

  In the above embodiment, the attachment member 17 for attaching the main frame 10 to the screed plate 11 is a single member, but 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. Also in this case, it is preferable that a hole for draining be formed in each mounting member.

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

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

  While the invention has been described in detail, the foregoing description is in all points illustrative only and is not intended to limit the scope thereof. It goes without saying that 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.

Reference Signs List 1 road pavement machine 2 vehicle 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 sheathed heater 13 tip member 14 mounting member 14a Recess 15 Holding member 15a Recess 15b Rib 16 Heat shield 17 Mounting member 17a Hole (water draining means)

Claims (10)

It is a screed device used for a road paving machine,
With screed plate,
A sheathed heater arranged to heat the screed plate;
A pressing portion for pressing the sheathed heater against the screed plate;
And a heat shielding unit configured to block heat radiation upward of the sheathed heater.   The screed device according to claim 1, wherein the pressing portion has a recess in which the sheathed heater is inserted.   The said pressing part has provided the said recessed part in the rib part of the bottom face, The screed apparatus of Claim 2 characterized by the above-mentioned.   The screed device according to any one of claims 1 to 3, wherein the sheathed heater is held down by the plurality of holding portions arranged in parallel.   The said heat shielding part consists of metal heat shielding boards, The screed apparatus in any one of the Claims 1-4 characterized by the above-mentioned.   The screed device according to claim 5, wherein the heat shield plate is disposed on the pressing portion.   The screed apparatus according to any one of claims 1 to 6, further comprising a draining means for draining water around the sheathed heater to the outside.   8. The screed device according to claim 7, wherein the water draining means is a hole provided in a member disposed between the screed plate and a main frame of the screed device.   9. The screed device according to claim 8, further comprising a cover for preventing the holes from clogging.   A road paving machine comprising the screed device according to any one of claims 1 to 9.