Vibration-proof support structure for muffler in engine-driven work machine

Abstract

To suppress generation of noise due to vibrations of an engine drive type working machine which are caused from the start to stable operation of an engine.SOLUTION: Movement restriction means 40 for a muffler 30 consisting of a pedestal 32 and a muffler body 31 mounted on a top plate 322 thereof by: fitting the muffler onto a frame 12 of a sound insulation box 10 through a vibration insulation member 33; providing a pair of brackets 41, 42 having planes 41a, 42a orthogonal to an axial direction of an engine 2 on an inner surface of a side wall (side cover 113) of an engine hood 11 arranged in the same direction as the axial direction of an output shaft of the engine 2; and holding a stopper member 43 formed of an elastic body fixed to the muffler between planes of both the brackets. Large vibrations of the muffler which are caused in the axial direction of the output shaft of the engine are thereby suppressed from the start of the engine 2 of the engine drive type working machine 1 to its stable operation, thereby suppressing noise at the start of the engine drive type working machine.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a vibration-proof support structure for a muffler in an engine-driven working machine, and more specifically to a vibration-proof support structure for a muffler that makes it possible to reduce noise caused by vibrations from a muffler installed in an engine-driven working machine being transmitted to a soundproof box. [Background technology]

[0002] As shown in Figure 11, in an engine-driven work machine 200 that is composed of a work machine main body 206 such as a generator and compressor (a generator in the illustrated example), an engine 202 that drives the work machine main body 206, and other necessary equipment, these components are housed and packaged in a soundproof box 210 that is composed of a frame 212 on which these components are placed and a bonnet 211 that covers the top of this frame 212.This prevents noise from leaking outside the soundproof box 210 and also prevents the components from being directly exposed to wind and rain even when used outdoors.

[0003] In such an engine-driven work machine 200, a configuration is generally adopted in which the interior of the soundproof box 210 is divided into two chambers, front and rear, in the longitudinal direction of the soundproof box 210 by a partition wall 213 that vertically divides the inside of the soundproof box 210, one of which is an engine chamber 210a that houses the engine 202 and the work machine main body 206, and the other is an exhaust chamber 210b for discharging cooling air that has passed through the engine chamber 210a outside the machine.

[0004] An opening (not shown) that connects the engine compartment 210a and the exhaust chamber 210b is provided in the central part of this partition wall 213, and a radiator core (not shown) is attached to this opening. A radiator fan 203 that blows cooling air to the radiator core is also provided, so that the cooling air introduced into the engine compartment 210a from outside the aircraft through an intake port (not shown) provided in the hood 211 on the engine compartment 210a side cools the inside of the engine compartment 210a, passes through the radiator core, reaches the exhaust chamber 210b, and is then discharged outside the aircraft through the exhaust port 219 provided in the exhaust chamber 210b.

[0005] In the engine-driven working machine 200 configured as described above, the muffler 230 of the engine 202 is arranged in the exhaust chamber 210b, and the engine 202 arranged in the engine chamber 210a and one end of the muffler 230 arranged in the exhaust chamber 210b are connected via the exhaust pipe 220, and one end of the tail pipe 225 is connected to the other end of the muffler 230, and the other end of this tail pipe 225 is arranged facing outside the machine via the exhaust port 219, so that the exhaust gas that has passed through the muffler 230 can be discharged outside the machine.

[0006] In this way, the engine 202 and the muffler 230 are connected by the exhaust pipe 220, but the aforementioned partition wall 213 exists between the engine compartment 210a in which the engine 202 is located and the exhaust compartment 210b in which the muffler 230 is located.

[0007] For this reason, this partition wall 213 has an opening 213a consisting of a notch or hole, etc., for passing the exhaust pipe 220 from the engine compartment 210a to the exhaust compartment 210b, as shown in Figure 12, and the exhaust pipe 220 is inserted into this opening 213a and fixed to the partition plate 213.

[0008] As an example, in the configuration shown in Figures 11 and 12, the exhaust pipe 220 is fixed to a bracket 214 attached to the partition wall 213 by bolting or other means using a U-bolt 215, so that the exhaust pipe 220 does not come into contact with the opening edge of the opening 213a even when vibrations occur.

[0009] Furthermore, the muffler 230 arranged in the exhaust chamber 210b is also fixed by bolts or the like to the frame 212 or the inner wall of the bonnet 211 (the frame 212 in the illustrated example) within the exhaust chamber 210b.

[0010] In the soundproof engine-driven working machine 200 configured as described above, a flexible pipe 221 (see Figure 11), which is a metal pipe or the like having a bellows structure, is provided in a part of the exhaust pipe 220, and by making this part deformable, it is configured to be able to absorb vibrations transmitted from the engine 202.

[0011] However, even if such a flexible pipe 221 is installed, it is not possible to completely absorb the vibrations generated by the engine 202, and the vibrations transmitted from the engine 202 via the exhaust pipe 220 are transmitted to the partition wall 213, and further to the frame 212 and bonnet 211 that secure the partition wall 213, causing the entire soundproof box 210 to vibrate and generating noise.

[0012] In addition, the vibrations transmitted from the engine 202 to the exhaust pipe 220 are also transmitted to the muffler 230 connected to the exhaust pipe 220, and the muffler 230 itself generates vibrations as the exhaust gas expands and contracts within the muffler 230.As a result, the vibrations of the muffler 230 are transmitted to the entire soundproof box 210 via the frame 212 that secures the muffler 230, causing the soundproof box 210 to generate noise.

[0013] In order to prevent noise generated by such vibrations, particularly noise generated by the transmission of vibrations of the muffler 230 to the soundproof box 210, Patent Document 1 listed below proposes that muffler side stays 262 protruding from both ends of the muffler 230 be placed and fixed on soundproof box side stays 261 protruding from the inner wall of the bonnet 211 of the soundproof box 210 via vibration-damping members 233 made of an elastic material such as vibration-damping rubber, as shown in Figure 13, thereby making it difficult for vibrations of the muffler 230 to be transmitted to the bonnet 211 (see Figures 4 and 7 of Patent Document 1). [Prior art documents] [Patent documents]

[0014] [Patent Document 1] Patent No. 4427210 Summary of the Invention [Problem to be solved by the invention]

[0015] In a configuration in which the stay 262 on the muffler side is attached to the stay 261 on the soundproof box side via a vibration-damping member 233 such as vibration-damping rubber, as in the device configuration introduced in Patent Document 1 cited above, the vibration of the muffler 230 is attenuated by the vibration-damping member 233 and is therefore not easily transmitted to the soundproof box 210 side, and it is expected that this will have the effect of reducing the vibration of the soundproof box 210 caused by the muffler 230 as a vibration source, and the noise generated by this.

[0016] However, even in the configuration described in the above-mentioned Patent Document 1, the exhaust pipe 220 is fixed to the partition wall 213 by, for example, bolting the flange 222 provided on the exhaust pipe 220 to the partition wall 213 as shown in Figure 13, and therefore the generation of noise caused by vibrations transmitted from the engine 202 to the exhaust pipe 220 vibrating the entire soundproof box 210 via the partition wall 213 has still not been eliminated.

[0017] Therefore, in order to prevent the generation of noise caused by the vibrations of the exhaust pipe 220 being transmitted to the soundproof box 210 via the partition wall 213, the inventors of the present invention tried to operate the engine 202 with the exhaust pipe 220 released from its fixation to the partition wall 213, while maintaining the structure adopted in Patent Document 1 in which the muffler 230 is attached to the soundproof box 210 via the vibration-damping member 233.

[0018] As a result, after engine 202 is started, until engine 202 operation stabilizes, muffler 230 vibrates with a relatively large amplitude in the axial direction of the output shaft of engine 202 (the direction of the white arrow in Figure 11), and it was confirmed that this vibration of muffler 230 is transmitted to soundproof box 210, resulting in a new problem in which the noise level at engine start-up actually increases.

[0019] Furthermore, when the muffler 230 vibrates greatly in the axial direction of the engine output shaft (the direction of the white arrow in Figure 11), the exhaust pipe 220 swings up and down greatly, interfering with the edge of the opening 213a in the partition wall 213 and generating new noise, and the flexible pipe 221 attached to the exhaust pipe 220 is repeatedly and greatly deformed, which may cause metal fatigue in the flexible pipe 221 and cause it to break relatively early.

[0020] Furthermore, if a structure is adopted in which the muffler 230 is fixed by attaching the stay 261 on the soundproof box side to the side wall of the bonnet 211, which has a relatively low strength, as in the above-mentioned Patent Document 1, there is a concern that such large vibrations occurring in the muffler 230 will not provide the strength necessary to support the muffler 230.

[0021] Therefore, the inventors of the present invention investigated the mechanism by which such vibration occurs in order to suppress the large vibration that occurs in the muffler 230 when the exhaust pipe 220 is released from its fixation to the partition wall 213.

[0022] As a result, it was found that this increase in vibration of the muffler 230 was caused by the expansion and contraction of the exhaust gas inside the exhaust pipe 220 when the engine 202 was started, causing the flexible pipe 221 to expand and contract.

[0023] In other words, in a structure in which the exhaust pipe 220 is fixed to the partition wall 213, the expansion and contraction of the flexible pipe 221 is restricted by the partition wall 213, whereas in a structure in which the exhaust pipe 220 is released from its fixed position on the partition wall 213, the flexible pipe 221 is able to expand and contract freely without being restricted by the partition wall 213, and it was found that this expansion and contraction causes the muffler 230 to shake in the longitudinal direction of the flexible pipe 221, and therefore in the axial direction of the output shaft of the engine 202.

[0024] On the other hand, it has been confirmed that the vibration of the muffler 230 caused by the expansion and contraction of the flexible pipe 221 occurs only when the engine 202 is started, and after the engine has transitioned to a stable operating state, the muffler 230 no longer vibrates with large amplitude in the axial direction of the output shaft of the engine 202, and changes to a relatively small vibration moving in a direction perpendicular to the axial direction of the engine output shaft (the direction indicated by the blackened arrow in Figure 12).

[0025] It has also been confirmed that small vibrations perpendicular to the axial direction of the engine output shaft that occur when engine 202 is in a stable operating state can be damped by adopting a configuration in which muffler 230 is attached to soundproof box 210 via vibration-damping member 233 such as vibration-damping rubber.

[0026] From the above results, if it is possible to suppress the large vibrations that occur in the muffler 230 after the engine 202 starts and before it transitions to a stable operating state, not only can the noise generated by the muffler as a vibration source be suppressed, but it will also be possible to adopt a structure in which the exhaust pipe 220 is not fixed to the partition wall 213 or the bonnet 211, and therefore the vibrations transmitted from the exhaust pipe 220 to the soundproof box 210 can also be reduced, thereby significantly improving the quietness of the engine-driven working machine 200.

[0027] Therefore, the present invention aims to provide a vibration-proof support structure for a muffler in an engine-driven working machine that can suppress the large vibrations of the muffler that occur from the time the engine starts until it transitions to stable operation. [Means for solving the problem]

[0028] The means for solving the problems are described below together with the reference numerals used in the description of the embodiment of the invention. These reference numerals are used to clarify the correspondence between the description of the claims and the description of the embodiment of the invention, and needless to say, are not used to restrict the interpretation of the technical scope of the present invention.

[0029] In order to achieve the above object, the vibration-proof support structure of the muffler in the engine-driven working machine of the present invention comprises: A vibration-proof support structure for a muffler 30 in an engine-driven working machine comprising a soundproof box 10 having a frame 12 serving as a base for mounting components and a bonnet 11 covering the frame 12, an engine 2 housed in the soundproof box 10, a working machine body 6 driven by the engine 2, an exhaust pipe 20 at least part of which is made of a flexible pipe 21, and a muffler 30 connected to the engine 2 via the exhaust pipe 20, The muffler 30 comprises a muffler body 31 which is a silencer, and fixing legs 32 for fixing the muffler body 31 onto the frame 12, and the fixing legs 32 are attached to the frame 12 via vibration-isolating members 33 when the muffler 30 is positioned on a line L (see Figure 4) which is an extension of the axis of the output shaft of the engine 2 in a plan view, and In plan view The movement of the muffler 30 in a direction perpendicular to the axial direction of the output shaft of the engine 2 (in the direction of the blackened arrow in FIG. 4) No regulation A movement restricting means 40 is provided within the soundproof box 10 to restrict movement of the muffler 30 in the axial direction of the output shaft (the direction of the white arrow in Figure 4) (Claim 1).

[0030] The movement restricting means 40, The engine 2 is provided with a pair of brackets 41, 42 provided on the inner surface of the side wall (113, or 113 and 114) of the bonnet 11 arranged in a direction parallel to the axial direction of the output shaft of the engine 2, or on one of the mufflers 30 (in the illustrated example, the inner surface of the bonnet side wall 113, or 113 and 114), and a stopper member 43 made of an elastic body fixed to the other (in the illustrated example, the muffler 30), The pair of brackets 41, 42 may each be provided with flat surfaces 41a, 42a that are perpendicular to the axial direction of the output shaft of the engine 2, and the stopper member 43 may be sandwiched between the flat surfaces 41a, 42a (Claim 2: Figures 6, 7, 9, 10).

[0031] The fixing legs 32 of the muffler 30 described above may be, for example, made by attaching angle bars to both longitudinal ends of the muffler body 31, but preferably, the muffler body 31 is placed and fixed on a stand having legs 321, 321 and a top plate 322 erected on the legs 321, 321, and the stand is used as the fixing legs 32, thereby positioning the muffler body 31 on the frame 12 and spaced apart from the frame 12, and The lower ends of the legs 321, 321 of the stand 32 may be attached to the frame 12 via the vibration-isolating member 33 (claim 3: see FIGS. 2, 3, and 5).

[0032] In the engine-driven working machine 1, the soundproof box 10 is provided with a partition wall 13 that vertically divides the soundproof box 10, the engine 2 is housed in one chamber (engine chamber 10a) separated by the partition wall 13, and the muffler 30 is housed in the other chamber (exhaust chamber 10b), The engine 2 and the muffler body 31 of the muffler 30 are connected by the exhaust pipe 20 which is not fixed to either the partition wall 13 or the bonnet 11, It is preferable that the opening 13a in the partition wall 13, through which the exhaust pipe 20 is inserted, is formed with dimensions such that the exhaust pipe 20 does not interfere with the opening edge of the opening 13a even when vibration occurs (Claim 4).

[0033] Furthermore, the muffler 30 is arranged so that the length direction of the muffler body 31 is perpendicular to the axial direction of the output shaft of the engine 2, and It is preferable to provide the movement restricting means 40 at least on the end side of the muffler 30 opposite to the connection side of the exhaust pipe 20 (claim 5: see Figs. 6 and 7). [Effects of the Invention]

[0034] With the configuration of the present invention as described above, the vibration-proof support structure for the muffler in the engine-driven working machine 1 of the present invention can achieve the following significant effects.

[0035] By providing a movement restriction means 40 to restrict the movement of the muffler 30 in the axial direction of the output shaft of the engine 2, it is possible to prevent the muffler 30 from vibrating significantly in the axial direction of the output shaft of the engine 2 from the time the engine 2 starts until it reaches stable operation.

[0036] As a result, it is possible to reduce the noise generated from the start of the engine 2 until it reaches stable operation, and it is also possible to prevent repeated large deformations from being applied to the flexible pipe 21 attached to the exhaust pipe 20, thereby extending the life of the flexible pipe 21.

[0037] Furthermore, since the movement restriction means 40 restricts the movement of the muffler in the axial direction of the output shaft of the engine 2, it is possible to effectively prevent damage, etc., caused by the muffler 30 vibrating greatly due to vibrations during transportation, for example, when the engine-driven working machine 1 is loaded onto the bed of a truck or the like and transported, which repeatedly and significantly deforms the flexible pipe 21 of the exhaust pipe 20.

[0038] On the other hand, this movement restriction means 40 does not restrict the movement of the muffler 30 in a direction perpendicular to the axial direction of the output shaft of the engine 2, so when the engine 2 transitions to stable operation and the vibration of the muffler 30 changes to small vibrations in a direction perpendicular to the axial direction of the output shaft of the engine 2, such small vibrations are not easily transmitted to the side walls of the bonnet 11 via the movement restriction means 40.

[0039] Furthermore, such small vibrations are damped by the vibration-damping member 33 provided between the fixing legs 32 of the muffler 30 and the frame 12, making it difficult for the vibrations of the muffler 30 to be transmitted to the frame 12, thereby achieving a reduction in noise after the engine 2 has transitioned to stable operation.

[0040] Such movement restriction means 40 is composed of a pair of brackets 41, 42 provided on either the inner surface of the side wall (113, or 113 and 114) of the bonnet 11 or on one of the mufflers 30, and a stopper member 43 made of an elastic body fixed to the other, and the stopper member 43 is sandwiched between the flat surfaces 41a, 42a of the pair of brackets 41, 42. Despite the relatively simple structure, this configuration can reliably restrict only the movement of the muffler 30 in the axial direction of the output shaft of the engine 2, without restricting the movement of the muffler 30 in a direction perpendicular to the axial direction of the output shaft of the engine 2.

[0041] Furthermore, in a configuration in which the muffler body 31 is placed on and fixed to a stand, and the stand serves as fixing legs 32 for fixing the muffler body 31 to the frame 12, the distance from the muffler body 31 to the vibration-damping member 33 can be made long, so even if the vibration-damping member 33 is made of a material that is sensitive to heat, such as vibration-damping rubber, it is possible to prevent the vibration-damping member 33 from deteriorating prematurely due to the heat of the muffler body 31.

[0042] As described above, by providing the movement restriction means 40, large vibrations of the muffler 30 when the engine 2 is started are suppressed, and when the vibration-proof support structure for the muffler of the present invention is adopted in an engine-driven working machine 1 equipped with a soundproof box 10 whose interior is divided into two chambers by a partition wall 13, it becomes possible to adopt a structure in which the exhaust pipe 20 is not fixed to the partition wall 13, and by forming an opening 13a in the partition wall 13 that divides the interior of the soundproof box 10 for inserting the exhaust pipe 20 with dimensions that prevent the exhaust pipe 20 from interfering with the opening edge even when vibrations occur, it is possible to prevent vibrations of the exhaust pipe 20 from being transmitted to the soundproof box 10 via the partition wall 13, thereby achieving improved quietness not only when the engine 2 is started but also after it has transitioned to stable operation.

[0043] Furthermore, in a configuration in which the muffler body 31 is positioned so that its longitudinal direction is perpendicular to the axial direction of the output shaft of the engine 2, it has been experimentally confirmed that by adopting a configuration in which the movement restriction means 40 is provided at least on the end side of the muffler 30 opposite the connection side of the exhaust pipe 20, a higher noise suppression effect can be obtained compared to when the movement restriction means 40 is provided only on the end side of the connection side of the exhaust pipe 20. [Brief explanation of the drawings]

[0044] [Figure 1] FIG. 1 is an external perspective view of an engine-driven working machine. [Figure 2] 1 is a perspective view of an engine-driven working machine with a portion of the hood (a rear panel 112, a side panel 114, and a top panel 115) removed. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. [Figure 6] FIG. [Figure 7] FIG. 10 is an enlarged plan view of a muffler portion showing a modified example of the movement restricting means. [Figure 8] FIG. 10 is a rear perspective view of the engine-driven working machine showing another modified example of the movement restricting means. [Figure 9] FIG. 10 is an enlarged plan view of a muffler portion showing another modified example of the movement restricting means. [Figure 10] FIG. 10 is an enlarged plan view of a muffler portion showing yet another modified example of the movement restricting means. [Figure 11] FIG. 1 is a side perspective view of a conventional engine-driven working machine. [Figure 12] FIG. 1 is a rear perspective view of a conventional engine-driven working machine. [Figure 13] FIG. 1 is an explanatory diagram of a vibration-proof support structure for a muffler in Patent Document 1. DETAILED DESCRIPTION OF THE INVENTION

[0045] Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0046] [Overall configuration of engine-driven work machine] The symbol 1 in the figure indicates an engine-driven working machine to which the vibration-damping support structure of the present invention is applied, and this engine-driven working machine 1 is configured as a package-type engine-driven working machine, as shown in Figures 2 and 3, in which a soundproof box 10 houses a working machine main body 6 (see Figure 3) including a generator, compressor, etc., which are the components of the engine-driven working machine, an engine 2 that drives the working machine main body 6, and a muffler 30 connected to the engine 2 via an exhaust pipe 20.

[0047] As shown in Figure 1, the aforementioned soundproof box 10 that houses the components of the engine-driven work machine 1 has a bonnet 11 consisting of a front panel 111, a rear panel 112, side panels 113 and 114, and a top panel 115, and a frame 12 that serves as a base on which the components are placed.By covering the frame 12 with the aforementioned bonnet 11 while the components of the engine-driven work machine 1 are placed, the components can be housed within the soundproof box 10.

[0048] The space within this soundproof box 10 is divided into two chambers by a partition wall 13 arranged perpendicular to the longitudinal direction of the soundproof box 10, as shown in Figures 2 and 3. An engine chamber 10a that houses the engine and the main body of the work machine is formed in one of the divided spaces, and an exhaust chamber 10b that discharges the cooling air that has passed through the engine chamber 10a outside the machine is formed in the other space.

[0049] Within the engine compartment 10a, the engine 2 is positioned so that the axial direction of its output shaft is perpendicular to the longitudinal direction of the soundproof box 10, and therefore perpendicular to the partition wall 13, and the radiator fan 3 provided on the engine 2 is configured to generate cooling air toward the partition wall 13.

[0050] An opening is provided in the central part of this partition wall 13, connecting the engine compartment 10a and the exhaust chamber 10b. A radiator core 4 (see Figures 3 and 4) is attached to this opening, and the cooling air generated by the radiator fan 3 is blown onto the radiator core 4. This allows the cooling air introduced into the engine compartment 10a from outside the aircraft through the intake ports 116, 117 (see Figure 1) provided in the side panels 113, 114 of the hood 11 at the position where the engine compartment 10a is formed to cool the inside of the engine compartment 10a, then pass through the radiator core 4 to reach the exhaust chamber 10b, and then be discharged outside the aircraft through the exhaust port 119 (see Figure 1) provided in the exhaust chamber 10b.

[0051] A muffler 30 is placed in this exhaust chamber 10b, and the engine 2 placed in the engine chamber 10a and the muffler 30 (muffler body 31 of the muffler 30) placed in the exhaust chamber 10b are connected by an exhaust pipe 20 that penetrates the partition wall 13 and is placed across the two chambers 10a and 10b.One end of the tail pipe 25, which is connected to the muffler 30 (muffler body 31), is positioned with the other end facing outside the aircraft through the exhaust port 119, so that exhaust gas that has passed through the muffler 30 (muffler body 31) can be discharged outside the aircraft.

[0052] 〔scarf〕 The aforementioned muffler 30 placed in the exhaust chamber 10b is composed of a muffler body 31, which is a silencer, and fixing legs 32 for attaching the muffler body 31 to the frame 12, as shown in Figures 2 and 3. In the illustrated embodiment, the muffler body 31 is placed on and fixed to a base, which serves as the aforementioned fixing legs 32.

[0053] Furthermore, this fixing leg 32 is not limited to being constructed using a stand as in the configuration shown in the figure, but may also be constructed by directly attaching angle bars or the like to both longitudinal end faces of the muffler body 31, and various configurations can be adopted without being limited to the configuration shown in the figure.

[0054] In the illustrated embodiment, as described above, the base on which the muffler body 31 is placed is made of fixing legs 32, and the muffler body 31 is positioned at a predetermined height above the frame 12, in the illustrated example at a position on the extension of the rotation axis of the radiator fan 3, making it easier for cooling air to reach the muffler 30.

[0055] In this embodiment, the stand 32 is composed of a pair of legs 321, 321 erected on the frame 12 as shown in Figures 2 and 5, and a top plate 322 erected on the upper ends of the legs 321, 321, but the configuration of the stand 32 is not limited to the configuration shown in the figure, and various structures can be adopted as long as they can position the muffler body 31 at a predetermined height within the exhaust chamber 10b.

[0056] The muffler 30 is attached to the frame 12 via an anti-vibration member 33 such as anti-vibration rubber, and in the illustrated embodiment in which the aforementioned base 32 is used as the fixing leg, the lower ends of the legs 321, 321 provided on the base 32 are attached to the frame 12 via the anti-vibration member 33.

[0057] In this manner, by placing the muffler body 31 on the stand 32 and attaching the vibration-damping member 33 to the lower ends of the legs 321, 321 of the stand 32, even if the vibration-damping member 33 is made of a material that is weak to heat, such as vibration-damping rubber, the vibration-damping member 33 can be positioned away from the muffler body 31, which is the heat source, and the vibration-damping member 33 can be prevented from prematurely deteriorating due to the heat from the muffler body 31.

[0058] One longitudinal end of the muffler body 31, which is placed and fixed on the stand 32, is connected to the exhaust port of the engine 2 via an exhaust pipe 20 made of a flexible pipe 21, such as a metal pipe with a bellows structure, at least a portion of which is deformable.

[0059] In order to connect the exhaust port of the engine 2 located in the engine compartment 10a with the muffler body 31 located in the exhaust compartment 10b via the exhaust pipe 20, an opening 13a is provided in the partition wall 13 for passing the exhaust pipe 20 through.

[0060] The exhaust pipe 20 is configured so as not to be fixed to the partition wall 13 or the bonnet 11, and the aforementioned opening 13a provided in the partition wall 13 is formed to a size that prevents the exhaust pipe 20 from interfering with the opening edge of the opening 13a even when the exhaust pipe 20 vibrates.

[0061] In this embodiment, as an example, the opening 13a is formed with a diameter that is approximately 20 mm larger than the outer diameter of the exhaust pipe 20 at the portion that is inserted into the opening 13a, so that a gap Δ2 (see Figure 5) of approximately 10 mm is created between the outer diameter of the exhaust pipe 20 and the opening edge of the opening 13a.

[0062] By configuring it in this manner, it is possible to prevent vibrations from the exhaust pipe 20 from being transmitted to the soundproof box 10 via the partition wall 13, thereby preventing the generation of noise that would otherwise accompany the transmission of such vibrations.

[0063] In addition, one end of the tail pipe 25 is connected to the other longitudinal end of the muffler body 31, and by positioning the other end of this tail pipe 25 facing outside the aircraft through the exhaust port 119, the exhaust gas that has passed through the muffler body 31 can be discharged outside the aircraft.

[0064] The muffler 30 configured as described above is arranged on a line L extending from the axis of the output shaft of the engine 2 when viewed in a plane, as shown in Figure 4, and in the illustrated embodiment, the longitudinal direction of the muffler body 31 is arranged in a direction perpendicular to the axial direction of the output shaft of the engine 2, and therefore in the width direction of the soundproof box.

[0065] [Movement restriction means] The muffler 30 configured as described above is permitted to move in a direction perpendicular to the axial direction of the output shaft of the engine 2 (the direction indicated by the blackened arrow in Figure 4) by the movement restriction means 40, while being restricted from moving in the axial direction of the output shaft of the engine 2 (the direction indicated by the white arrow in Figure 4).

[0066] As shown in Figure 6, this movement restriction means 40 is composed of a pair of brackets 41, 42 provided on the inner surface of the side wall (side cover 113 in the illustrated example) of the bonnet 11 arranged in a direction parallel to the axial direction of the output shaft of the engine 2, and a stopper member 43 made of elastic material fixed to the muffler 30.

[0067] Of these, brackets 41, 42 are each provided with flat surfaces 41a, 42a that are perpendicular to the axial direction of the output shaft of engine 2, and the two brackets 41, 42 are attached to the inner surface of side cover 113 with these flat surfaces 41a, 42a facing each other at a predetermined distance.

[0068] The stopper member 43 is sandwiched in the space between the flat surfaces 41a and 42a provided on the pair of brackets 41 and 42.

[0069] By configuring in this manner, movement of the muffler 30 in the axial direction of the output shaft of the engine 2 (the direction indicated by the white arrow in Figure 6) is restricted, while movement of the muffler 30 in a direction perpendicular to the axial direction of the output shaft of the engine 2 (the direction indicated by the black arrow in Figure 6) is permitted.

[0070] As shown in the enlarged view in Figure 6, the aforementioned stopper member 43, which is one of the components constituting the movement restriction means 40, is attached to the side of the top plate 322 of the stand 32 by bolting or other means to a Z-shaped metal fitting 45 that protrudes toward the inner wall of the side panel 113 of the hood 11, and the aforementioned stopper member 43 made of an elastic material such as rubber is attached to the tip of this Z-shaped metal fitting 45.

[0071] The configuration of the stopper member 43 is not limited to the example shown in the figure, and various configurations can be adopted as long as they can cooperate with the pair of brackets 41, 42 to restrict movement of the muffler 30 in the axial direction of the output shaft of the engine 2. For example, as shown in Figure 7, a rubber bumper attached to the corner of the top plate 322 of the frame 32 can be used as the stopper member 43', and this stopper member 43' can be clamped between the flat surfaces 41a, 42a of the pair of brackets 41, 42.

[0072] In addition, in a configuration in which such a rubber bumper is used as the stopper member 43', as shown as a modified example in Figure 7, the stopper member 43' may also be provided at the opposite corner in the width direction of the top plate 322, and a pair of brackets 41, 42 may be configured to clamp the top plate 322 of the stand 32 together with these two stopper members 43', 43' from the width direction.

[0073] Furthermore, in the embodiment described with reference to Figures 6 and 7, a configuration was described in which the stopper members 43, 43' are both provided at the corners of the top plate 322 of the stand 32, but instead of this configuration, as shown in Figures 8 and 9, for example, a mounting bracket 45' protruding toward the side panel 113 on the back surface in the center of the width direction of the top plate 322 of the stand 32 may be provided, and the stopper member 43 may be attached to the tip of this mounting bracket 45', and the mounting position is not limited to the configuration shown.

[0074] On the other hand, a pair of brackets 41, 42 provided on the inner wall of the side panel 113 (114) sandwich the stopper members 43, 43' between their flat surfaces 41a, 42a.

[0075] These brackets 41, 42 may be provided by separately attaching angle irons or the like that will become brackets 41, 42 to side panels 113, 114 by welding or other means, as shown in Figure 9, or one or both of brackets 41, 42 may be constructed from components that are already provided on side panels 113, 114.By configuring them in this way, it is possible to reduce the number of parts and the assembly labor required.

[0076] As an example, in the embodiment shown in Figure 6, the bent portion provided on the side edge of the side panel 113 forms one bracket 41, and the side surface of the fuel filler cover protruding from the inner surface of the side panel 113 forms the other bracket 42, and a stopper member 43 is sandwiched between these two members.

[0077] In addition, in the embodiment shown in Figures 7 and 10, the bent portion provided on the side edge of the side panel 113 (, 114) forms one bracket 41, while the other bracket 42 is formed by attaching a separate angle bar to the inner surface of the side panel 131 (, 114).

[0078] The distance between the flat surfaces 41a, 42a of this pair of brackets 41, 42 must be such that the stopper member 43 can be inserted (clamped) without elastic deformation, and is formed to be the same width as the stopper member 43 or slightly wider.

[0079] The gap δ (0 to X) between the stopper member 43 and the flat surfaces 41a, 42b of the brackets 41, 42, indicated by the symbol δ in Figure 6, is preferably 0 (zero) in order to restrict movement of the muffler 30 in the axial direction of the output shaft of the engine 2 (the direction indicated by the white arrow in Figure 6).

[0080] On the other hand, in order to prevent small vibrations that occur in the muffler 30 after the engine 2 has transitioned to a stable operating state in a direction perpendicular to the axial direction of the output shaft of the engine 2 (the direction indicated by the blackened arrow in Figure 6) from being transmitted to the side panel 113, it is desirable to separate the stopper member 43 from the flat surfaces 41a, 42b of the brackets 41, 42.

[0081] The maximum value X of such a gap δ (0 to X) may correspond, for example, to the maximum value of the movement range Δ (see Figure 4) of the engine and work machine body attached to the frame 12 via a vibration-damping member (7 mm in this embodiment), or to the distance Δ2 between the outer diameter of the exhaust pipe 20 and the opening edge of the opening 13a provided in the partition wall 13 (see Figure 5: 10 mm in this embodiment).

[0082] As an example, this movement restricting means 40 may be provided on one longitudinal end side of the muffler body 31 (in the illustrated example, on the attachment side of the tail pipe 25), as shown in Figures 6 and 7, or it may be provided on each of the longitudinal end sides of the muffler body 31, as shown in Figures 9 and 10.

[0083] However, when adopting a configuration in which the movement-restricting means 40 is provided only on one longitudinal end side of the muffler body 31 as shown in Figures 6 and 7, it is preferable to provide the movement-restricting means 40 on the longitudinal end side of the muffler body 31 opposite the attachment side of the exhaust pipe 20 (in the illustrated example, the end side on the attachment side of the tail pipe 25).

[0084] It has been experimentally confirmed that by providing the movement restriction means 40 at this position, the vibration damping effect can be improved compared to when the movement restriction means 40 is provided only on the opposite side (the side where the exhaust pipe 20 is attached).

[0085] In the embodiment described with reference to Figures 6 to 10, the stopper members 43, 43' are both described as being attached to the top plate 322 of the stand 32, but this is not limited to this position, and the stopper members 43, 43' may also be attached to the legs 321 of the stand 32 or the muffler body 31.

[0086] In addition, in all of the illustrated embodiments, a stopper member 43 is provided on the muffler 30 side and a pair of brackets 41, 42 are provided on the inner wall of the side panel 113 (, 114) of the bonnet 11, but the opposite configuration may also be adopted, in which a pair of brackets 41, 42 are provided on the muffler 30 side and a stopper member 43 is provided on the inner surface of the side panel 113 (, 114) of the bonnet, and the configuration is not limited to the illustrated embodiments.

[0087] [Effect, etc.] When the engine 2 is started in an engine-driven working machine 1 equipped with a muffler 30 supported by the vibration-proof support structure configured as described above, the flexible pipe 21 of the exhaust pipe 20 expands and contracts, repeatedly applying a force to the muffler 30 that tends to move it in the axial direction of the output shaft of the engine 2, from the time the engine 2 starts until it transitions to a stable operating state.

[0088] However, movement of the muffler 30 in the axial direction of the output shaft of the engine 2 is restricted by the stopper member 43 of the movement restriction means 40 being clamped between the flat surfaces 41a, 42a of the brackets 41, 42, and the range of movement of the muffler 30 is limited to the range of the sum of the gap δ formed between the stopper member 43 and the flat surfaces 41a, 42a of the brackets 41, 42 and the deformation amount of the stopper member 43, thereby preventing the muffler 30 from vibrating significantly.

[0089] As a result, it is possible to significantly reduce the vibration of the soundproof box 10 that occurs from the start of the engine 2 until it transitions to stable operation, and the noise that accompanies this vibration.

[0090] Furthermore, by preventing the muffler 30 from vibrating significantly when the engine 2 is started, the flexible pipe 21 of the exhaust pipe 20 can be prevented from being repeatedly subjected to large deformations, thereby extending the life of the flexible pipe 21.

[0091] Furthermore, by suppressing the large vibrations of the muffler 30 that occur when the engine is started, there is no longer any need to fix the exhaust pipe 20 to the partition wall 13 or the bonnet 11, and the vibrations of the exhaust pipe 20 are prevented from being transmitted to the soundproof box 10 via the fixed parts.

[0092] On the other hand, the pair of brackets 41, 42 provided on the movement restriction means 40 restrict the movement of the stopper member 43 in the axial direction of the output shaft of the engine 2, but do not restrict the movement of the stopper member 43 in a direction along the planes 41a, 42a of the brackets 41, 42, i.e., in a direction perpendicular to the axial direction of the output shaft of the engine 2.

[0093] As a result, when the operating state of the engine 2 stabilizes and the vibration of the muffler 30 changes to small vibrations perpendicular to the axial direction of the output shaft of the engine 2, the vibration of the muffler 30 in this direction is not transmitted to the movement control means 40, and therefore is not transmitted to the side panel 113 (, 114).

[0094] In addition, such small vibrations of the muffler 30 are damped by the vibration-damping member 33 provided between the lower end of the leg 321 of the stand 32 and the frame 12, thereby suppressing the vibrations transmitted to the soundproof box via the frame 12.

[0095] As a result, the vibration-proof support structure of the muffler of the present invention can attenuate both the noise and vibration that occurs from the time the engine 2 starts until it reaches stable operation, and the noise and vibration that occurs after it has transitioned to stable operation, making it possible to provide an engine-driven working machine that is quieter. [Explanation of symbols]

[0096] 1 Engine-driven work equipment 2 engines 3 Radiator fan 4 Radiator Core 6 Work machine body (generator) 10 Soundproof box 10a Engine compartment 10b Ventilation room 11. Bonnet 111 Front Panel 112 Rear panel 113,114 Side panel (hood side wall) 115 Top Panel 116,117 Air intake 119 Exhaust port 12 frames 13 Partition Wall 13a opening 20 exhaust pipe 21 Flexible pipe 25 tailpipe 30 Muffler 31 Muffler body (silencer) 32 Fixing legs (stand) 321 Legs 322 Top plate 33 Vibration-proofing material 40 Movement Control Measures 41,42 Bracket 41a, 42a Flat surface (bracket) 43, 43' Stopper member 45 Z-shaped bracket 45' Mounting Bracket 200 Engine-driven work equipment 202 Engine 203 Radiator fan 206 Work machine body (generator) 210 Soundproof Box 210a Engine compartment 210b Ventilation room 211 Bonnet 212 frames 213 Partition Wall 213a opening 214 Bracket 215 U-bolt 219 Exhaust port 220 exhaust pipe 221 Flexible Pipe 222 flange 225 tailpipe 230 Muffler 233 Vibration-proofing material 261 Stay on the soundproof box side 262 Muffler side stay L: The extension of the axis of the engine output shaft

Claims

1. A vibration-proof support structure for a muffler in an engine-driven working machine, comprising: a soundproof box having a frame serving as a base for mounting components and a bonnet covering the frame; an engine housed in the soundproof box; a working machine body driven by the engine; an exhaust pipe at least a portion of which is made of a flexible pipe; and a muffler connected to the engine via the exhaust pipe, The muffler includes a muffler body that is a silencer and fixing legs that fix the muffler body to the frame, and the fixing legs are attached to the frame via vibration-isolating members in a state where the muffler is positioned on a line extending from the axis of the output shaft of the engine in a plan view, and A vibration-proof support structure for a muffler in an engine-driven working machine, characterized in that a movement restriction means is provided within the soundproof box, which does not restrict movement of the muffler in a direction perpendicular to the axial direction of the engine output shaft in a plan view, but restricts movement of the muffler in the axial direction of the output shaft.

2. The movement restriction means a pair of brackets provided on either the inner surface of the side wall of the bonnet arranged in a direction parallel to the axial direction of the output shaft of the engine or the muffler, and a stopper member made of an elastic body fixed to the other, A vibration-proof support structure for a muffler in an engine-driven working machine as described in claim 1, characterized in that the pair of brackets each have a flat surface perpendicular to the axial direction of the output shaft of the engine, and the stopper member is sandwiched between said flat surfaces.

3. The muffler body is placed on and fixed to a stand having legs and a top plate installed on the legs, and the stand serves as the fixing legs, thereby disposing the muffler body on the frame and spaced apart above the frame; 3. A vibration-isolating support structure for a muffler in an engine-driven working machine according to claim 1 or 2, wherein lower ends of the legs of the frame are attached to the frame via the vibration-isolating member.

4. the soundproof box is provided with a partition wall that vertically divides the soundproof box, and the engine is accommodated in one chamber separated by the partition wall, and the muffler is accommodated in the other chamber, The engine and the muffler body of the muffler are connected by the exhaust pipe that is not fixed to either the partition wall or the hood, and A vibration-proof support structure for a muffler in an engine-driven working machine as described in any one of claims 1 to 3, characterized in that the opening in the partition wall through which the exhaust pipe is inserted is formed with dimensions such that the exhaust pipe does not interfere with the opening edge of the opening even when vibrations occur.

5. The muffler is disposed so that the length direction of the muffler body is perpendicular to the axial direction of the output shaft of the engine, A vibration-proof support structure for a muffler in an engine-driven working machine as described in any one of claims 1 to 4, characterized in that the movement-restricting means is provided at least on the end side of the muffler opposite the connection side of the exhaust pipe.

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