Low-noise type road milling machine

Abstract

To provide a low-noise type road milling machine by reducing driving noise and the like that are generated around an engine of a road milling machine and radiate to the outside.SOLUTION: A machine is configured to comprise: a road milling machine main body 11; an engine attached to the road milling machine main body 11; an engine hood 19 connected to the road milling machine main body 11 for forming an engine room 18 which, together with the road milling machine main body 11, houses and installs the engine; an air inlet 20 and an exhaust outlet 21 which connect from the outside to the inside of the engine room 18; a first noise reducing material 22A attached to the road milling machine main body 11 side through covering the entire outer surface of the air inlet 20 while ensuring ventilation; and a second noise reducing material 22B attached to the road milling machine main body 11 side through covering the outer side of the exhaust outlet 21.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a low-noise road milling machine, and more particularly to a low-noise road milling machine that mills the surface of a paved road surface and discharges the milled material. [Background technology]

[0002] The cutting and overlay method has been known as a method for repairing pavement surfaces made of cement concrete or asphalt mixtures. This method involves using a road cutting machine to remove surface areas of the pavement that have been damaged by repeated running of large vehicles on the pavement, and then repaving the surface with new materials (see, for example, Patent Document 1).

[0003] A self-propelled road milling machine known from Patent Document 1 and the like comprises a relatively long cutting drum that is rotatably mounted on the road milling machine body and has cutting bits on its outer periphery, a first belt conveyor adjacent to the front of the cutting drum (in the work or construction direction) that receives the cutting material cut by the cutting drum from the cutting drum and transports it outside the road milling machine body, a second belt conveyor that receives the cutting material from the first belt conveyor and transports it to a transport vehicle (truck) or the like, and an engine that serves as the power source for the road milling machine, etc.

[0004] While the road milling machine is self-propelled by the driving force of the engine, the cutting drum is also driven at high speed by the driving force of the engine to cut the surface portion of the pavement, and the cutting material is transported from the rotating cutting drum onto a belt conveyor, and further from the belt conveyor directly to a transport vehicle or the like, and the cut material is removed from the pavement to be repaired. This method is mainly used for large-scale repair work of paved roads, particularly because it allows the cutting drum to cut a wide width of the pavement to be repaired at once and remove the cut material.

[0005] In the self-propelled road milling machine with the above-mentioned structure, the engine is used as the driving force, and the machine runs independently by the driving force of the engine, and the cutting drum is rotated at high speed by the driving force of the engine to cut the surface part of the paved road surface, so a large engine is required, and the engine is always driven at high speed during operation. Furthermore, when cutting the surface part of the paved road surface, cutting noise is generated in addition to engine noise. Therefore, when working in an area adjacent to residential areas, it directly stimulates the senses of the residents, and there are concerns about the impact on their daily lives. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2017-75489 A Summary of the Invention [Problem to be solved by the invention]

[0007] As mentioned above, the operation of road milling machines, which generates engine noise and cutting noise, has various effects on the daily lives of residents and workers. For example, noise not only reduces the quality of sleep, but also impairs concentration and memory, causing stress and irritability. It can also cause hearing loss and hearing impairment, and research has shown that it increases the risk of lifestyle-related diseases such as heart disease and high blood pressure, which is a problem that has a significant impact on the health and happiness of residents.

[0008] Therefore, a technical problem arises that needs to be solved in order to provide a low-noise road milling machine by suppressing the driving noise that is generated around the engine of the road milling machine and dissipated to the outside, and the present invention aims to solve this problem. [Means for solving the problem]

[0009] The present invention has been proposed to achieve the above-mentioned object, and the invention described in claim 1 provides a low-noise road cutting machine that cuts and discharges surface portions of a paved road surface, comprising an engine attached to the road cutting machine body of the road cutting machine, an engine hood that, together with the road cutting machine body, forms an engine compartment in which the engine is housed and installed, an opening provided in the engine hood and connecting the inside of the engine compartment to the outside of the engine compartment in a manner that allows ventilation, and a noise suppression material attached to the road cutting machine body side, covering the entire outer surface of the opening while ensuring ventilation, and suppressing noise emitted from around the engine by absorbing and blocking sound.

[0010] According to this configuration, the entire outer surface of the opening that connects the inside of the engine room to the outside of the engine room in a manner that allows ventilation is covered with a noise suppression material in a state where ventilation is ensured. Therefore, the driving noise generated around the engine is suppressed by absorbing and insulating it with the noise suppression material, so the amount of noise leaking out of the engine room is reduced, resulting in low noise. This makes it possible to realize a low-noise road milling machine.

[0011] The invention described in claim 2 provides a low-noise road surface cutting machine having the configuration described in claim 1, wherein the noise suppression material includes a sound-absorbing material that absorbs noise around the engine and a sound-insulating material that blocks noise around the engine.

[0012] With this configuration, the drive noise generated around the engine can be suppressed by the sound absorbing and sound insulating materials, making it possible to realize an even quieter road milling machine.

[0013] The invention as recited in claim 3 provides a low-noise road surface milling machine having the configuration as recited in claim 1, wherein the noise suppression material is equipped with a vibration-damping material that suppresses vibrations transmitted through the vehicle body structure.

[0014] According to this configuration, the vibrations generated in the engine compartment and transmitted from the engine through the vehicle body structure can be suppressed by the noise suppression material, making it possible to realize an even quieter road milling machine.

[0015] The invention as recited in claim 4 provides a low noise type road milling machine as recited in claim 1, wherein the opening is an air intake port for drawing air into the engine compartment.

[0016] According to this configuration, noise generated around the engine and attempting to leak out through the intake port is suppressed and reduced by the noise suppression material covering the outside of the intake port.

[0017] The invention as recited in claim 5 provides a low noise type road milling machine as recited in claim 1, wherein the opening is an exhaust port for discharging air from within the engine compartment.

[0018] According to this configuration, noise generated around the engine and attempting to leak out through the exhaust port is suppressed and reduced by the noise suppression material covering the outside of the exhaust port. Effect of the Invention

[0019] According to the present invention, the engine driving noise and vibrations generated around the engine are suppressed by the noise suppression material arranged to cover the outside of the engine compartment so that they do not leak out of the engine compartment, so the amount of noise leaking out of the engine compartment is reduced, resulting in low noise. This makes it possible to achieve a low-noise road milling machine. [Brief description of the drawings]

[0020] [Figure 1] 1 is a side view of an entire road milling machine shown as one example of an embodiment of the present invention, and shows a schematic diagram of a position where a noise suppression material is attached. FIG. [Diagram 2] FIG. 2 is a perspective view of the road milling machine as a whole seen from the rear, showing the position where the noise suppression material is attached. [Diagram 3] FIG. 2 is an enlarged rear view of the road milling machine, showing the position where the noise suppression material is attached. [Figure 4] 1A to 1C are diagrams showing an example of a noise suppression material attached to the rear surface of the same road milling machine, where (a) is a front view, (b) is a BB cross-sectional view of (a), and (c) is a CC cross-sectional view of (a). [Diagram 5] FIG. 2 is an enlarged plan view of the rear of the road milling machine, showing the position where the noise suppression material is attached. [Figure 6] FIG. 2 is an enlarged side view of the rear of the road milling machine, showing a schematic diagram of the position where the noise suppression material is attached. [Figure 7] FIG. 4 is a plan view showing an example of a frame for holding noise suppression material attached to a side of the same road surface milling machine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] In order to achieve the object of providing a low-noise road cutting machine by suppressing driving noise etc. generated around the engine of the road cutting machine and radiating to the outside, the present invention provides a low-noise road cutting machine that cuts and discharges the surface portions of a paved road surface, and is realized by comprising an engine attached to the road cutting machine body of the road cutting machine, an engine hood which, together with the road cutting machine body, forms an engine compartment in which the engine is housed and installed, an opening provided in the engine hood and connecting the inside of the engine compartment to the outside of the engine compartment in a manner that allows ventilation, and a noise suppression material attached to the road cutting machine body side, covering the entire outside of the opening while ensuring ventilation, and suppressing noise radiating from around the engine. EXAMPLES

[0022] An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. In the following embodiment, when the number, value, amount, range, etc. of components are mentioned, the number is not limited to the specific number, and may be more or less than the specific number, unless otherwise specified or when it is clearly limited to a specific number in principle.

[0023] In addition, when referring to the shape or positional relationship of components, etc., this includes things that are substantially similar or approximate to those shapes, etc., unless otherwise specified or considered to be clearly different in principle.

[0024] In addition, the drawings may exaggerate characteristic parts to make the features easier to understand, and the dimensional ratios of the components may not be the same as the actual ones. In addition, in cross-sectional views, hatching of some components may be omitted to make the cross-sectional structure of the components easier to understand.

[0025] In the following description, the expressions indicating directions such as up, down, left, right, etc. are not absolute, but are appropriate when each part of the low noise road milling machine of the present invention is in the posture depicted, but if the posture is changed, the interpretation should be changed accordingly. Also, the same elements are given the same symbols throughout the description of the embodiments.

[0026] Figures 1 and 2 show a road milling machine 10 as a low-noise road milling machine according to the present invention, with Figure 1 being a side view showing the overall appearance, and Figure 2 being a perspective view of the entire road milling machine as seen from the rear. In the following explanation, the left side in the left-right direction of Figure 1 will be referred to as the front side in the front-to-rear direction of the road milling machine 10, the right side as the rear side, the up-down direction as up-down, and the direction perpendicular to the paper surface as left-right.

[0027] 1 and 2 has a road milling machine body 11 equipped with an engine (not shown). The road milling machine body 11 of the road milling machine 10 has running wheels 12 (front wheels 12A, rear wheels 12B, rear wheels 12C) at the front and rear positions on the left and right, respectively, and the running wheels 12 are rotated by the driving force of the engine to enable self-propelling.

[0028] In addition, a cutting drum box 14 with a cutting drum chamber 13 provided therein is attached to the road surface milling machine body 11 between the front wheels 12A and the rear wheels 12B. In the cutting drum chamber 13, a relatively long cutting drum 15 (see FIG. 1) with cutting bits provided on the outer periphery for cutting the surface portion of the paved road surface is arranged in the left-right direction (vehicle width direction). Furthermore, a ground roller 16 capable of contacting the surface portion of the paved road surface is attached to the underside of the cutting drum box 14. When cutting work is not being performed, the cutting drum box 14 rises to a position (position in FIG. 1) where the ground roller 16 is far away from the surface portion of the paved road surface, and retreats together with the cutting drum 15. That is, the cutting drum box 14 and the cutting drum 15 housed in the cutting drum chamber 13 of the cutting drum box 14 are attached to the road surface milling machine body 11 so as to be able to move up and down and slide left and right.

[0029] On the other hand, when cutting work is being performed, the road surface milling machine body 11 is lowered until the ground contact roller 16 comes into contact with the surface portion of the paved road surface, and the cutting drum 15 is also lowered until it comes into contact with the surface portion of the paved road surface. Then, the cutting drum 15 is rotated by the driving force of the engine that realizes the self-propelled road surface milling machine body 11, and this rotation causes the cutting drum 15 to cut the surface portion of the paved road surface with cutting bits attached to the outer circumferential surface.

[0030] The cutting material cut by the cutting drum 15 is sent onto a first belt conveyor (not shown) provided on the road surface milling machine body 11, and is sent to the front of the road surface milling machine body 11 by the first belt conveyor, and is further transported onto a transport vehicle (truck) (not shown) via a conveyor device 17 having a second belt conveyor provided at the front of the road surface milling machine body 11. When the cutting work by the cutting drum 15 is completed, the cutting drum 15 and the cutting drum box 14 are returned to the raised position shown in FIG.

[0031] Incidentally, this type of road milling machine 10 is self-propelled by rotating the running wheels 12 of the road milling machine body 11 with the driving force of the engine. The same driving force of the engine also rotates the cutting drum 15 to cut the surface of the paved road surface, and the cutting material generated there is transported to a transport vehicle or the like via a conveyor device 17 for removal. For this reason, the engine requires a large output, and since a large output is required, the noise generated during operation is also large. Moreover, the engine is constantly driven during operation. In addition, at the same time as the engine is driven, wind noise caused by the rotation of the engine cooling fan, driving noise of the fan belt, wind noise when air passes through an opening, and the like are generated. That is, in the present invention, these engine driving noises, wind noises of the engine cooling fan, driving noise of the fan belt, wind noise when air passes through an opening, and the like are collectively referred to as "sounds around the engine". And these sounds around the engine are one of the main noises during operation. Therefore, in the road milling machine 10 of this embodiment, as a structure for reducing the leakage of engine-related sounds (driving noise) to the outside, a noise suppression material 22 is provided covering the outside of the engine room 18 in which the engine is housed and installed, in order to suppress and reduce the leakage of engine-related sounds generated within the engine room 18 to the outside.

[0032] As shown in Figure 2, the engine hood 19 is provided with an air intake port 20 serving as an intake opening for taking in outside air from the outside into the engine compartment 18, corresponding to the rear side of the road milling machine 10, and exhaust ports 21 serving as exhaust openings for discharging the outside air taken into the engine compartment 18 from the air intake port 20 to outside the engine compartment 18 are provided on each of the left and right sides of the road milling machine 10.

[0033] In addition, the noise suppression material 22, which suppresses and reduces noise around the engine in the engine room 18 from leaking to the outside, consists of a first noise suppression material 22A attached to cover the outside of the intake port 20, and a second noise suppression material 22B attached to cover the outside of the exhaust port 21.

[0034] Figures 3 and 4 show an example of the first noise suppressing material 22A in the noise suppressing material 22. More specifically, Figure 3 is an enlarged view showing a schematic view of the rear surface of the road milling machine 10 to which the first noise suppressing material 22A is attached so as to cover the outside of the intake port 20 of the engine hood 19. Figure 4 shows the first noise suppressing material 22A alone, where (a) is a front view of the first noise suppressing material 22A as seen from the rear side, (b) is a BB cross-sectional view of (a), and (c) is a CC cross-sectional view of (a).

[0035] 3 and 4, the first noise suppression material 22A comprises a frame body 24 formed into a roughly rectangular shape with an opening 23 in the center, and a noise suppression member 25 attached within the frame body 24 in a state in which the opening 23 is covered over almost the entire surface when viewed from the front.

[0036] The frame 24 is made of a metal material such as aluminum steel. On the other hand, the noise suppression member 25 is formed in a louver shape with three horizontal beams arranged across both the left and right sides of the frame 24, and has an intake slit 26 between the beams, which opens diagonally downward. Therefore, outside air (air) is taken into the engine room 18 through the intake slit 26 and the intake port 20. In addition, the noise suppression member 25 has a sound absorbing material (not shown) arranged on the inner side facing the engine room 18, which absorbs sounds around the engine, and a sound insulation material (not shown) is attached to the outside of the sound absorbing material, i.e., the outer side opposite the engine room 18, in a multi-layered combination with the sound absorbing material, which reflects the sounds around the engine that have already been attenuated by passing through the sound absorbing material to the engine room 18 side. In other words, the noise suppression member 25 can attenuate and suppress sounds around the engine with the sound absorbing material and the sound insulation material. In FIG. 4(b), the dashed line at the lower end of the noise reduction member 25 indicates a punched metal.

[0037] The first noise suppression material 22A, having a noise suppression member 25 attached to the opening 23 of the frame body 24, is attached to the rear side of the road milling machine 10, covering the entire outside of the air intake 20 of the engine hood 19, and is fixed to a predetermined location of the engine hood 19 with bolts or the like, as shown in Figure 3.

[0038] In this way, in the road milling machine 10 in which the first noise suppressing material 22A is attached to a predetermined location of the engine hood 19 to cover the outside of the intake port 20 of the engine hood 19, the entire surface of the intake port 20 leading to the engine compartment 18 is covered by the first noise suppressing material 22A. Therefore, when vibrations and sounds transmitted from the engine through the body structure in the engine compartment 18, such as engine noise generated around the engine, attempt to leak out from the intake port 20 to the outside, the engine noise is absorbed and suppressed by the sound absorbing material and sound insulating material in the noise suppression member 25 because substantially the entire surface of the intake port 20 is covered by the first noise suppressing material 22A.

[0039] Figures 5 to 7 show an example of the second noise suppression material 22B in the noise suppression material 22. More specifically, Figure 5 is an enlarged view showing a schematic view of the rear upper surface of the road milling machine 10 in which the entire outer surface of the exhaust port 21 of the engine hood 19 is covered with the second noise suppression material 22B and attached to the engine hood 19, Figure 6 is an enlarged view showing a schematic view of the rear side surface of the road milling machine 10 in which the entire outer surface of the exhaust port 21 of the engine hood 19 is similarly covered with the second noise suppression material 22B and attached to the engine hood 19, and Figure 7 shows an example of a frame 27 for attaching the second noise suppression material 22B shown in Figures 5 and 6 to a peripheral portion of the exhaust port 21 of the engine hood 19.

[0040] The second noise suppression member 22B is a block-shaped member having intake and exhaust properties, which is a substantially hexahedron, and is attached to the engine hood 19 around the exhaust port 21 of the engine hood 19 using a frame 27 that fixes the block-shaped noise suppression member 28 to a predetermined location on the engine hood 19. The noise suppression member 28, like the first noise suppression member 22A, has a function of absorbing and insulating engine sounds, and has a sound-absorbing material (not shown) that absorbs sounds around the engine arranged on the inner side facing the engine room 18, and a sound-insulating material (not shown) that insulates the sounds around the engine that have already been attenuated by passing through the sound-absorbing material is attached to the outside of the sound-absorbing material, i.e., the outer side opposite the engine room 18, in a multi-layered combination with the sound-absorbing material. That is, the noise suppression member 28 can attenuate and suppress sounds around the engine with the sound-absorbing material and the sound-insulating material. As the noise suppression member 28, for example, a honeycomb soundproof panel "Texel SAINT" manufactured by Gifu Plastic Industry Co., Ltd. is used.

[0041] The frame 27 is made of a metal material such as aluminum steel, and "Texel SAINT" is fitted as a holding panel 29 in each portion of the frame 27 that faces the surface of the engine hood 19. The noise suppression members 28 are sandwiched between the holding panels 29 and the outer surface of the engine hood 19, and are arranged to cover the outside of the exhaust port 21 of the engine hood 19. A vibration suppression material may be provided to suppress vibration of the second noise suppression material 22B transmitted via the vehicle body structure. The vibration suppression material may be, for example, Hayadamper, Showdamp (registered trademark), Karmoon sheet, or the like that can be attached to the second noise suppression material 22B.

[0042] In this way, in the road milling machine 10 in which the second noise suppression material 22B is attached to cover the outer side and the outer top of the engine hood 19 including the exhaust port 21 while ensuring breathability, when sounds generated around the engine in the engine room 18, i.e., engine noise, etc., leak out from the exhaust port 21 to the outside, the exhaust port 21 and its surrounding areas are covered with the second noise suppression material 22B, so that the engine noise, etc. is absorbed and insulated by the sound absorbing material and sound insulating material in the noise suppression member 28, and is suppressed and reduced. In addition, vibrations transmitted through the vehicle body structure are suppressed by the vibration-damping material. As a result, noise, etc. leaking out from the side of the road milling machine 10 to the outside can be suppressed and reduced by the second noise suppression material 22B.

[0043] Therefore, in the road milling machine 10 of this embodiment, the first noise suppression material 22A and the second noise suppression material 22B can effectively suppress and reduce the noise generated around the engine from leaking to the outside.

[0044] The present invention can be modified in various ways without departing from the spirit of the present invention, and it is natural that the present invention covers such modifications. [Explanation of symbols]

[0045] 10: Road milling machine (low noise road milling machine) 11: Road milling machine body 12: Running wheel 13: Cutting drum room 14: Cutting drum box 15: Cutting drum 17: Conveyor device 18: Engine room 19: Engine hood 20: Air intake 21: Exhaust port 22: Noise suppression material 22A: No. 1 noise suppression material 22B: Second noise suppression material 23 :Aperture 24:Frame body 25: Noise suppression materials 26: Slit 27:Frame body 28: Noise suppression materials 29: Retaining panel

Claims

1. A low-noise road milling machine that mills and discharges a surface portion of a paved road surface, an engine attached to a main body of the road milling machine; an engine hood forming an engine room for accommodating and installing the engine together with the road surface milling machine body; an opening provided in the engine hood and connecting the inside of the engine compartment to the outside of the engine compartment in a manner allowing ventilation; and a noise suppression material that covers the entire outer surface of the opening while ensuring ventilation and is attached to the road surface milling machine body, and absorbs and insulates noise emitted from around the engine to suppress the noise. A low noise type road surface milling machine characterized by:

2. The noise suppression material includes a sound absorbing material that absorbs sounds around the engine and a sound insulating material that insulates sounds around the engine.

2. A low noise type road milling machine according to claim 1.

3. The noise suppression material includes a vibration-damping material that suppresses vibrations transmitted through a vehicle body structure.

2. A low noise type road milling machine according to claim 1.

4. 2. The low noise type road milling machine according to claim 1, wherein the opening is an air intake port for drawing air into the engine compartment.

5. 2. The low noise type road milling machine according to claim 1, wherein the opening is an exhaust port for discharging air taken into the engine compartment.

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