JP5449211B2 - Rotary snow plow equipped with hybrid system - Google Patents

Description

The present invention relates to a rotary snowplow mounting a hybrid system using a power as part of a power source.

  Conventionally, for example, a rotary snowplow in which an auger, a blower, a chute and the like are mounted on a vehicle is well known. In this type of conventionally known rotary snowplow, the accumulated snow is broken by the rotating action of the auger, and the broken snow is sucked and collected by a blower and discharged through a cylindrical chute. Therefore, it generally has a configuration for removing snow from roads and the like. On the other hand, recently, a hybrid system that uses electric power as at least a part of a power source such as an engine attracts attention. Since this type of hybrid system uses electric power as a part of a power source for operating a vehicle or the like, it can reduce the environmental load, and various vehicles are used in the automobile industry, which places importance on environmental problems. It has come to be installed in. For this reason, it has been proposed that such a hybrid system is also adopted as a power system for a rotary snowplow as described in the present application.

  As described above, a rotary snowplow is a hybrid system for using electric power not only as a part of a power source for moving a vehicle but also as a part of a power source of a mechanism unit such as an auger or a blower described above. When using this hybrid system, a large current is consumed when attempting to operate various mechanisms such as moving a vehicle, driving an auger, or sucking a blower, for example. It is essential that the temperature of various components of this hybrid system (for example, electric motors, generators, inverters, boost choppers, etc.), in particular, the temperature of large-capacity batteries becomes high. A cooling mechanism for efficiently cooling the component equipment is required.

  Here, since the rotary snowplow to which the present invention is applied is a vehicle for removing snow accumulated on the road or the like, snow inherently exists on the road on which the snowplow is expected to travel. If the hybrid system is installed, it is assumed that the system is used under severe road conditions or usage conditions, such as when there is water that has melted snow. There is essentially a desire to avoid or prevent as much as possible from the viewpoint of water intrusion into the electrical component.

  Therefore, in order to avoid water splashing on the electrical components of the hybrid system, it is conceivable to make the hybrid system itself a sealed structure. However, if the hybrid system is configured with such a sealed structure, the battery As a result of the above-mentioned problem that the temperature of various devices of the hybrid system accompanying this becomes high, the various devices of the hybrid system including the battery are efficiently cooled. Will be further required.

  One solution is to provide a dedicated cooler or cooling mechanism for cooling the sealed hybrid system, although in this case the rotary snowplow is There is a problem that the cost is inevitably increased. In addition, there is a concern that the weight of the rotary snowplow main body increases and the contribution to the environmental load decreases despite the fact that the hybrid system is installed. Therefore, it is practically difficult to adopt a configuration in which the hybrid system has a sealed structure and further includes a dedicated cooler. Therefore, in order to avoid these problems, the external air intake action of the radiator fan of the radiator originally installed in the engine room of the vehicle to cool the engine mounted on the vehicle is used for cooling the hybrid system. It was examined whether it could not be used.

  However, in a conventionally known snowplow, the lower surface side of the engine room where the engine or the like is disposed is released, and further, a radiator grille is provided on the rear side of the engine room as viewed in the traveling direction of the snowplow. A configuration is adopted in which external air is taken in from the lower surface side of the engine room of the snowplow, and the outside air taken in for cooling is discharged from a radiator grill provided at the rear of the snowplow using a radiator fan for the snowplow. . In the case of such a conventional configuration, cooling external air is sucked from the lower surface side of the engine room in which the engine or the like is arranged, particularly from the vicinity of the lower part of the radiator fan in the engine room. Since the outside air for cooling is immediately discharged from the radiator grill to the outside of the engine room, depending on the radiator fan, the air flow of the outside air over the entire engine room is not generated, so the engine cooling water passing through the inside of the radiator is not Even if it can be cooled by outside air, the cooling effect of the entire engine room cannot be expected. Therefore, there has been a problem that the cooling effect of the hybrid system to be arranged in the engine room cannot be expected. Moreover, since the outside air for cooling is sucked from the lower surface side of the engine room, the snow existing on the road and the water that has melted are sucked into the engine room together with the outside air by the action of the radiator fan. It is conceivable that such snow and water will be applied to the hybrid system. Therefore, there has been a problem that such a conventionally known configuration cannot be employed as a cooling mechanism of a hybrid system mounted on a rotary snowplow.

  The invention disclosed in Patent Document 1 discloses a cooling structure or a cooling mechanism for cooling a battery in a hybrid construction machine. In Patent Document 1, the interior of a cabin on which an occupant rides is cooled. The structure which cools a battery using the cold heat from the air conditioner for this is disclosed.

  However, in the configuration disclosed in Patent Document 1, since it is necessary to arrange a battery adjacent to a cabin on which an occupant is boarded, the battery arrangement position is limited. There is a problem in that there is a restriction on the arrangement of. Further, in the configuration of Patent Document 1, only the battery can be cooled, and other elements constituting the hybrid system, such as an electric motor and a generator, and further cooling of an inverter, a boost chopper, etc. are considered. Therefore, there is a problem that the entire hybrid system cannot be cooled. Furthermore, since an air conditioner for cooling the cabin is used, it is assumed that this air conditioner uses a relatively expensive refrigerant-type cooling device. In addition to the cabin, the battery is also cooled. If it tries to do so, it is necessary to prepare a high-performance, and even more expensive refrigerant-type air conditioner, which is disadvantageous in terms of cost.

An object of the present invention is to prevent snow and melted water present on a road from being applied to a hybrid system in a rotary snowplow.

In order to achieve the above object, in the present invention,
A hybrid comprising at least an engine, a radiator having a radiator fan, and an engine room in which the engine and the radiator are arranged, and further arranged in the engine room in order to use electric power as part of a power source Oite the rotary snowplow comprising comprises a system, on one side of the engine room cover covering the engine room, a radiator grille for discharging the outside air captured by the radiator fan engine room outside are provided, the An outside air intake is provided on the side of the engine room cover opposite to the one side where the radiator grill is disposed, and outside air taken into the engine room from the outside air intake by the radiator fan passes through the radiator grill. through, while being discharged to the engine room outside the engine room lower surface wherein the hybrid system is arranged Suggest rotary snowplow, characterized in that it has a closed structure.

Furthermore, in the present invention, it is preferable that a battery chamber in which the battery of the hybrid system is disposed is provided outside the engine room and the air in the engine room is introduced into the battery chamber .

Furthermore, in the present invention, it is preferable that the air in the engine room is introduced into the battery room via an air duct .

  Furthermore, in the present invention, it is preferable that a wind guide fan for taking air in the engine room into the battery chamber is provided in the wind guide duct.

  Furthermore, in the present invention, it is preferable that the air guide fan is configured to be capable of adjusting a fan air volume.

Furthermore, in the present invention, it is preferable that the outside air intake port is provided with an intrusion prevention structure that prevents intrusion of water from the outside, and the intrusion prevention structure further includes a plate body having a substantially T-shaped cross section. It is preferable that there are a plurality of sheets, and the plurality of plate bodies are arranged in a stepwise manner and shifted in the front-rear direction continuously in the vertical direction .

According to the rotary snowplow of the present invention, water from the road is not applied to the hybrid system, and even if the cooling mechanism is configured in this way, the installation environment in the engine room of the hybrid system is not impaired.

1 is a schematic side view of an embodiment of a rotary snowplow employing a hybrid system cooling mechanism of the present invention. It is the schematic perspective view which looked at the rotary snowplow shown by FIG. 1 from the diagonally left rear upper side. FIG. 4 is a perspective view for explaining the hybrid system cooling mechanism of the present invention, and is a schematic perspective view of the rotary snowplow with the engine room cover removed leaving the outside air intake port as viewed from the upper left side obliquely rearward. is there. FIG. 2 is a perspective view for explaining the hybrid system cooling mechanism of the present invention, and is a schematic perspective view of the rotary snowplow with the engine room cover removed leaving the outside air intake port as viewed from the upper right rear side. is there. It is a general | schematic fragmentary sectional view for demonstrating one Example of the external air intake of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
First, FIG. 1 which is a schematic side view showing an embodiment of a rotary snowplow adopting the hybrid system cooling mechanism of the present invention, and the rotary snowplow shown in FIG. A schematic configuration of the rotary snowplow 100 according to the present invention will be described with reference to FIG. 2 which is a schematic perspective view. The rotary snowplow 100 according to the present invention is equipped with a hybrid system for using electric power as a part of a power source, and is well known to those skilled in the art except for the cooling mechanism of the hybrid system. Therefore, the overall configuration will be outlined.

  1 and 2, reference numeral 100 indicates the entire rotary snowplow. The rotary snowplow 100 mainly includes a road traveling vehicle 2 having an engine room 10 and a front of the traveling vehicle 2. The snow removal device 3 is provided. Further, the snow removal device 3 is provided with an auger 5 for collecting snow along the left-right direction of the snow removal device 3. The snow removal device 3 is provided between the auger 5 and the traveling vehicle 2. A snow removal device 6 having a blower and a chute for removing snow collected by the auger 5 in a predetermined direction is provided. Although the auger 5 is drawn in outline and not shown in detail, it has, for example, a helical ribbon shape and can be rotated between the left and right auger support members of the snow removal device 3. It is supported by. Furthermore, the traveling vehicle 2 is provided with a cabin 7 for a passenger to get on.

  In the rotary snowplow 100 as shown here, the snow accumulated by the rotating action of the auger 5 is broken, and the broken snow is sucked and collected by a blower and discharged through a cylindrical chute. Thus, it is configured to remove snow from roads and the like.

  Next, as shown in FIGS. 3 and 4, an engine 11 is mounted on the engine room 10 of the traveling vehicle 2 from the rear side from the center as viewed in the traveling direction of the rotary snowplow 100. A radiator 12 for cooling the cooling water or the like used for the engine is disposed further on the rear side than the engine 11. 3 and 4 are schematic perspective views for explaining the hybrid system cooling mechanism of the present invention. FIG. 3 shows an engine that covers the upper and side surfaces of the engine room while leaving an outside air intake port 18 to be described later. While FIG. 4 is a schematic perspective view of the rotary snow blower 100 with the chamber cover 20 removed as viewed from the upper left diagonally rear side, FIG. 4 is a schematic perspective view as viewed from the upper right diagonal rear side. Further, FIG. 4 shows some devices in the engine room (for example, an inverter 27 for power generation control, an inverter 28 for drive control, a boost chopper 29, etc.) in order to make the air guide duct 30 and the air guide fan 31 described later easier to see. Etc.) is also illustrated. Further, a radiator grill 22 is provided on the engine room cover 20 on the rearmost side of the engine room 10 where the radiator 12 and the like are disposed (see FIG. 2). Furthermore, the radiator 12 has a radiator fan 14 for taking outside air for cooling the cooling water flowing inside the radiator 12 into the engine room 10 from outside the engine room 10 and supplying or blowing the air to the radiator 12. The radiator fan 14 is configured, for example, as an impeller as is generally known, and is provided in front of or immediately before the radiator 12 when viewed in the vehicle traveling direction. In the drawing, since other components are arranged near the radiator fan 14 or there is a fan cover or the like, the radiator fan 14 is depicted by representing only the fan cover. As shown in the illustrated example, the outside air intake 18 is arranged separately from the engine room cover 20, and an opening into which the outside air intake 18 is inserted is provided at a corresponding position of the engine room cover 20. The outside air intake 18 may be provided on one side of the engine room cover 20, or the outside air intake 18 may be provided integrally with the engine room cover 20 by processing one side of the engine room cover 20.

  Furthermore, the rotary snowplow 100 according to the present invention is equipped with a hybrid system for using electric power as part of a power source, and the hybrid system has the same components as those of a generally known hybrid system. ing. In the illustrated example, for example, a nickel metal hydride battery 25 as a battery of the hybrid system, a breaker 26 of the hybrid system, an inverter 27 for power generation control, an inverter 28 for drive control, and the electric power stored in the battery 25 It can be seen that the boost chopper 29 for boosting the voltage, the generator 24 and the like are arranged inside the engine room 10 of the rotary snowplow 100. In the example shown here, the battery 25 is provided outside the engine room 10. However, depending on the design, the battery 25 can be arranged inside the engine room 10. Will also be described later.

  When a hybrid system having such various devices is mounted in the engine room 10 of the rotary snowplow 100, if the lower surface side of the engine room 10 of the rotary snowplow 100 is released as in the prior art, the radiator fan 14 The outside air for cooling that is taken into the engine room by being rotationally driven from the lower surface side of the engine room 10, in particular, from the lower surface side near the immediate lower part where the radiator fan 14 is disposed. It is taken inside and immediately discharged to the outside of the rotary snowplow 100 through the radiator 12 and the radiator grille 22. Therefore, since the atmospheric air on the front side in the engine room 10 is hardly replaced by the outside air taken in by the radiator fan 14, the hybrid system disposed in the engine room 10, particularly in the engine room inside, is used. Various components are not cooled by the airflow caused by the outside air taken in by the radiator fan 14. That is, the various components of the hybrid system that are at a high temperature are cooled only by their own heat dissipation action with respect to the ambient temperature at their arrangement position, and the cooling efficiency of these various components is very poor. Furthermore, in such a configuration in which outside air is taken in from the lower surface side of the engine room 10, snow from the road or water that has melted infiltrates into the engine room 10, so that the electrical equipment that dislikes water very much It is conceivable that the invading water may reach the parts, which may adversely affect the operation of the hybrid system.

  Therefore, in the present invention, for example, by providing a wall surface such as a partition wall on the lower surface side of the engine room 10, all the openings extending from the lower surface side of the engine room 10 to the inside of the engine room are eliminated, and the lower surface side of the engine room 10. I devised to deal with these problems by completely closing In this case, in order to efficiently replace the entire air inside the engine room 10 with the outside air taken in by the action of the radiator fan 14, a radiator grill 22 for discharging the outside air taken in by the radiator fan 14 is arranged. An outside air intake 18 is provided on a side surface facing the side surface or wall surface of the engine room cover 20. If constituted in this way, the air flow of the outside air taken into the engine room 10 by the rotating action of the radiator fan 14 of the radiator 12 originally provided in the rotary snowplow 100 passes through substantially the entire interior of the engine room. Therefore, various components of the hybrid system disposed inside the engine room 10 (for example, the battery 25, the hybrid system breaker 26, the inverter 27 for power generation control, the inverter 28 for drive control, the boost chopper 29, It is possible to use the air flow from the outside air to cool the generator 24, etc., so there is no need to provide a special cooler or cooling mechanism, and the entire hybrid system is cooled with an inexpensive and simple configuration. It becomes possible to do.

  Further, with such a configuration, the entire interior of the engine room 10 is cooled by the air flow of the outside air taken in by the radiator fan 14, so that various devices of the hybrid system can be placed near the radiator fan 14, for example. The necessity for examining or devising the cooling arrangement configuration such as arrangement is reduced, and these apparatuses can be arranged in any position, that is, freely if they are inside the engine room 10. Furthermore, since the lower surface side of the engine room 10 is completely blocked, water and snow do not enter the engine room 10 from the road, and as a result, water from the road is applied to the hybrid system. Can be resolved at the same time. Therefore, even if the cooling mechanism is configured in this way, not only does the installation environment of the hybrid system be impaired, but it is possible to improve rather than the conventional technology.

  In the example shown here, the radiator grille 22 is provided on the rear side surface of the engine room cover 20 as viewed in the traveling direction of the rotary snowplow 100, while the outside air intake 18 is provided on the rotary snowplow 100. Is provided on the side surface in front of the engine room cover 20 as viewed in the direction of travel. In the case of such a configuration, not only the intake of the air flow due to the rotational action of the radiator fan 14 but also the air flow of the outside air from the traveling direction generated in accordance with the operation of the rotary snow blower 100 in the traveling direction, Since it can be taken into the engine room 10, the hybrid system can be cooled more efficiently, which is preferable.

  Here, in the embodiment shown in FIGS. 3 and 4, the battery chamber 40 in which the battery 25 is disposed has a sealed structure, and the battery chamber 40 is provided outside the engine chamber 10. This is because, in the hybrid system for using electric power as a part of the power source of the rotary snowplow 100, the electric power to be stored in the battery 25 becomes very large, and therefore the battery chamber 40 in which the battery 25 is disposed. This is due to the response to the increase in size. That is, when considering the arrangement position in the rotary snowplow 100 of the battery chamber 40 that accommodates the battery 25 that has been enlarged due to its large capacity, when trying to arrange the large battery chamber 40 inside the engine room 10, Since the restriction on the arrangement position of other components in the engine room 10 becomes large, a countermeasure for the possibility that the battery room 40 may be required to be arranged outside the engine room 10 depending on the design conditions. It is shown. Accordingly, the present invention is not limited to the example illustrated here, and the battery chamber 40 can also be disposed inside the engine room 10. In the case where only the battery chamber 40 in the components of the hybrid system is provided outside the engine room 10 in this way, the battery chamber 40 is prevented in order to prevent snow or water that has been melted from being directly applied to the battery 25. Need to have a sealed structure. However, the battery 25 is a component that is expected to reach a particularly high temperature because it is repeatedly charged and discharged many times. Therefore, if the battery chamber 40 has a sealed structure, the inside of the battery chamber must be cooled efficiently. Don't be.

  Therefore, in the present invention, the air duct 30 for taking air inside the engine room 10 into the battery chamber 40 and the air taken from the battery chamber 40 through the air duct 30 are discharged from the battery chamber. An exhaust port (not shown) is provided, and the exhaust port is behind the radiator fan arrangement position as viewed in the air blowing direction of the radiator fan 14 and there is a flow of airflow of exhaust air by the radiator fan 14 It was configured to be arranged or opened at a position to be opened. Here, the rear side of the radiator fan arrangement position viewed in the air blowing direction of the radiator fan 14 means that the air flow taken in by the radiator fan 14 passes through the radiator fan 14 and is behind the radiator fan 14. Means the position behind the position where the radiator fan 14 is located when viewed in the direction of air flow, and the position where the flow of the air flow of the exhaust air by the radiator fan 14 exists is the radiator It means that the air flow taken in by the action of the fan 14 still maintains the flow direction by the action of the radiator fan 14 at the position of the discharge port or the opening position. Therefore, this discharge port may be disposed or opened between the radiator fan 14 and the radiator grille 22 or may be disposed or opened immediately after the radiator grille 22, for example. If comprised in this way, since the air volume of the radiator fan 14 is comparatively large, when the air volume by the ventilation effect | action of this radiator fan 14 is still maintained above a discharge port, the air inside a battery chamber is drawn out As a result, the air inside the battery chamber can be replaced with the air inside the engine room 10 through the air guide duct 30. In other words, the above-described discharge port may be arranged or opened at a position where the air inside the sealed battery chamber 40 can be sucked out by the action of the air flow of the discharge air of the radiator fan 14. .

  In order to make it easier for air in the engine room to flow into the battery chamber through the air guide duct 30, the opening direction of the air guide duct 30 is directed toward the flow direction of the air flow generated by the radiator fan 14. It is preferable to configure so as to open. If comprised in this way, since the air flow in the engine room 10 which generate | occur | produced by the radiator fan 14 flows in into the baffle duct 30 as it is, the air inside the battery chamber 40 is sucked out by the effect | action of the air flow of the radiator fan 14 In addition, the air flowing in from the air guide duct 30 has an effect of pushing out the air in the battery chamber 40, and the air in the battery chamber 40 can be replaced more easily, so that the battery chamber 40 can be cooled more efficiently. become.

  Further, as shown in the figure, a wind guide fan 31 for taking air in the engine room 10 into the battery chamber 40 can be provided in the wind guide duct 30. Providing the air guide fan 31 in this way is preferable because air in the engine room 10 can be reliably introduced into the battery room. Furthermore, if the fan air volume of the wind guide fan 31 is configured to be adjustable, the amount of air inside the engine room 10 flowing through the wind guide duct 30 can be adjusted, so that the temperature inside the battery room 40 is set to an appropriate temperature. It is suitable because it can be controlled to In this case, a temperature sensor or the like is provided inside the battery chamber 40, and the air volume of the air guide fan 31 can be adjusted according to the temperature monitored by the temperature sensor. Regarding air volume adjustment, as is generally known, for example, it is conceivable to control the fan rotation speed by adjusting the voltage supplied to the air guide fan 31 or the power supply frequency.

  By the way, as described above, when water is applied to the hybrid system, there is a high risk of water entering the electrical components. Therefore, it is desired to prevent water from entering the engine room 10 as much as possible. There is a great demand. For this reason, the outside air intake 18 is provided with an intrusion prevention structure that prevents intrusion of water from the outside. For example, even if snow or rain falls, snow and water can be easily discharged from the outside air intake 18. It is preferable that the amount of intrusion is as small as possible so as not to enter or even if it has entered. The intrusion prevention structure for preventing the entry of water from the outside can be, for example, a labyrinth structure 53 as shown in FIG. The labyrinth structure 53 shown in FIG. 5 is configured such that a plate body 54 having a substantially T-shaped cross section is continuously arranged in a stepped manner in the vertical direction, so that the outside air taken in from the plate body 54 arranged in a continuously stepped manner. However, it is arranged so that the air flow is bent along the cross section of the plate body 54 (see the arrow in the figure). By continuously arranging, the outside air that is a gas can bend and flow between the continuously arranged plate bodies 54, while the snow and rain contained in the outside air taken into the plate body 54. A configuration is adopted in which it is not possible to easily enter the engine room 10 by collision. Note that the labyrinth structure 53 shown in FIG. 5 is an example of an intrusion prevention structure, and snow or water is not easily infiltrated from the outside air intake 18 or even if it has entered, As long as the structure is configured so that the amount is as small as possible, other generally known intrusion prevention structures can be employed.

  Further, the outside air inlet 18 may be provided with a filter 55 for preventing the entry of foreign matters (for example, dust and dirt) from the outside over the entire surface. It is preferable to install the filter 55 together with the intrusion prevention structure described above, because the filter 55 can be expected to prevent water from entering.

  The preferred embodiments of the present invention have been described with reference to the drawings, but the present invention is not limited to the illustrated examples. For example, in the illustrated example, the radiator 12 is provided on the rearmost side of the engine room 10, and the radiator grill 22 is provided on the side surface behind the engine room cover 20 as viewed in the traveling direction of the rotary snowplow 100. The example in which the side surface of the engine room cover 20 provided with the outside air intake 18 is the side surface in front of the engine room cover as viewed in the traveling direction of the rotary snowplow 100 has been shown. The radiator 12 is disposed on either side of the engine room 10 in the left-right direction (that is, the width direction of the vehicle) as viewed in the horizontal direction with respect to the traveling direction, and the engine on the side where the radiator 12 is disposed A radiator grill 22 is provided on either of the left and right side surfaces of the chamber cover 20, and the outside air intake 1 is provided on any left and right side surfaces of the engine chamber cover 20 provided with the radiator grille 22. It can also be provided. Even if comprised in this way, since the external air taken in by the radiator fan 14 flows from the left-right direction over the whole engine room 10, the objective of this invention can be achieved.

  The present invention can be suitably used for a hybrid system cooling mechanism in a rotary snow plow equipped with a hybrid system.

DESCRIPTION OF SYMBOLS 10 Engine room 12 Radiator 14 Radiator fan 18 Outside air intake 20 Engine room cover 22 Radiator grill 24 Generator 25 Battery 26 Breaker for hybrid system 27 Inverter for power generation control 28 Inverter for drive control 29 Boost chopper 30 Wind guide duct 31 Wind guide fan 40 Battery compartment 100 Rotary snowplow

Japanese Patent No. 3649147

Claims (7)

A hybrid comprising at least an engine, a radiator having a radiator fan, and an engine room in which the engine and the radiator are arranged, and further arranged in the engine room in order to use electric power as part of a power source Oite to the rotary snowplow made with a system,
On one side of the engine room cover covering the engine room, a radiator grille for discharging the outside air captured by the radiator fan engine room outside it is provided,
An outside air intake is provided on the side of the engine room cover facing the one side where the radiator grille is disposed,
The outside air taken into the engine room from the outside air intake by the radiator fan is discharged outside the engine room through the radiator grille ,
A rotary snowplow characterized in that the lower surface of the engine room in which the hybrid system is arranged is sealed . 2. The rotary snow removal according to claim 1, wherein a battery chamber in which a battery of the hybrid system is disposed is provided outside the engine room, and air in the engine room is introduced into the battery chamber. Car . The engine room air through the air guide duct, characterized in that it is introduced into the battery compartment, a rotary plow according to claim 2. The rotary snowplow according to claim 3, wherein a wind guide fan for taking air in the engine room into the battery chamber is provided in the wind guide duct. The rotary snowplow according to claim 4, wherein the wind guide fan is configured to be capable of adjusting a fan air volume. The rotary snowplow according to any one of claims 1 to 5, wherein the outside air intake port includes an intrusion prevention structure that prevents entry of water from the outside. The intrusion prevention structure has a plurality of plate bodies having a substantially T-shaped cross section, and the plurality of plate bodies are arranged in a stepwise manner and shifted in the front-rear direction. The rotary snowplow according to claim 6 .

Images