JP2013194623A - Air cleaner for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air cleaner for a vehicle, in which intake noise can be reduced while decreasing engine output degradation and adverse influences upon a travel feeling.SOLUTION: An air cleaner (24) for a vehicle includes an air cleaner box (241) having a plurality of wall surfaces and cleans air to be supplied to an engine (21). In the air cleaner (24) for the vehicle, the rear panel (245) of the air cleaner box (241) is constituted of a high rigidity material, and intake noise is reduced while suppressing intake sound transmission in the air cleaner box (241).

Description

  The present invention relates to an air cleaner for a vehicle, and more particularly to an air cleaner for a vehicle of an off-road type motorcycle.

  In the motocross race sponsored by the International Federation of Motorcyclisms (FIM), the noise regulation (2 mM AX method) newly adopted in 2011 will be raised in 2013. In this noise regulation, the noise is measured when no load is applied and when the accelerator is fully open. For this reason, in the motocross racing vehicle (motocrosser), it is necessary to take new measures against noise according to the conditions of no load and full throttle.

  Noise when the motocrosser is unloaded and the accelerator is fully opened is classified into exhaust noise from the muffler and intake noise based on the intake air pulsation of the engine. In order to reduce the exhaust noise, it is effective to increase the exhaust pressure. However, when the exhaust pressure is increased, the exhaust efficiency is lowered, and there is a problem that the adverse effect on the engine output and the running feeling becomes extremely large. For this reason, it is difficult to satisfy the noise regulations while maintaining engine output and running feeling only by measures against exhaust noise.

  On the other hand, in order to reduce the intake noise, it is effective to make the vehicle air cleaner have a box shape and reduce the intake port to increase the intake resistance. However, when the intake resistance is increased, there is a problem in that the output of the engine is lowered and the running feeling is deteriorated. In view of this, there has been proposed a vehicle intake device capable of reducing intake noise without increasing intake resistance by devising the shape of the air cleaner box (see, for example, Patent Document 1).

  In the vehicle air intake device described in Patent Document 1, a stair-like step surface is provided on the wall surface of the air cleaner box so as to increase the thickness of the wall surface. Thereby, since the rigidity of the wall surface is improved, the vibration of the wall surface of the air cleaner box based on the intake air pulsation of the engine can be prevented, and the intake sound radiated outside the air cleaner box is reduced. Similarly, a proposal has been made to reduce the intake noise by providing a reinforcing rib for improving the rigidity of the wall surface of the air cleaner box.

JP 2010-071245 A

  However, if a staircase surface or a reinforcing rib is provided on the wall surface of the air cleaner box, the capacity in the air cleaner box may not be sufficiently secured, or the airflow in the air cleaner box may be disturbed by the staircase surface or the reinforcing rib. For this reason, although intake noise can be reduced, there is a problem that the engine output is reduced and the driving feeling is adversely affected.

  In addition, when the air cleaner box is provided with staircases and reinforcing ribs, there is a problem that the construction of the wall becomes complicated and the production cost increases, and the weight of the air cleaner for the vehicle increases as the wall thickness of the air cleaner box increases. .

  The present invention has been made in view of this point, and an object of the present invention is to provide a vehicle air cleaner that can reduce intake noise while reducing adverse effects on engine output reduction and running feeling.

  The vehicle air cleaner according to the present invention includes an air cleaner box having a plurality of wall surfaces, and in the vehicle air cleaner that purifies air supplied to the engine, the air cleaner box includes at least one wall surface made of a highly rigid material. It is characterized by.

  According to this configuration, the rigidity of at least one wall surface of the air cleaner box is improved by the high-rigidity material, and vibration of the wall surface of the air cleaner box due to engine intake pulsation or engine vibration is reduced. As a result, the transmission of the intake sound in the air cleaner box is suppressed, the intake noise is reduced, and the adverse effects on the engine output reduction and the running feeling can be reduced without increasing the intake resistance. Further, since the intake noise can be reduced simply by configuring the wall surface of the air cleaner box with a high-rigidity material, it is not necessary to provide ribs on the wall surface, and the shape of the air cleaner box is not complicated. As a result, it is possible to prevent adhesion of mud during traveling to the wall surface due to the complicated structure of the wall surface and deterioration of workability such as cleaning in the air cleaner box and element replacement. In addition, since the intake noise can be reduced by simply replacing the general-purpose resin material with a high-rigidity material without increasing the thickness of the wall surface of the air cleaner box, the weight increment is only the specific gravity of the general-purpose resin material and the high-rigidity resin material. The weight increment of the vehicle air cleaner can be kept low.

  In the vehicle air cleaner according to the present invention, the wall surface made of the high-rigidity material is a wall surface on the vehicle rear side. Generally, the wall on the rear side of the vehicle is formed with a larger area than other walls, so this configuration can further reduce intake noise by improving the rigidity of the wall that is large in area and easily vibrates. .

  In the vehicle air cleaner of the present invention, the high-rigidity material is a carbon fiber composite material containing carbon fibers. With this configuration, the rigidity of the wall surface can be improved while keeping the weight increment of the vehicle air cleaner low.

  Further, in the vehicle air cleaner of the present invention, a wall surface made of the carbon fiber composite material is fixed to an aluminum alloy body frame via an attachment member, and a potential difference between the attachment member and the carbon fiber composite material is: It is smaller than the potential difference between the carbon fiber composite material and the body frame. With this configuration, electrolytic corrosion based on the potential difference between the carbon fiber composite material and the aluminum alloy can be prevented.

  Moreover, in the said vehicle air cleaner of this invention, the rib which reinforces the said wall surface is provided in the wall surface comprised with the said highly rigid material. With this configuration, the rigidity of the wall surface of the air cleaner box can be further increased, and wall noise of the air cleaner box caused by engine intake pulsation or engine vibration can be suppressed, and intake noise can be further reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the air cleaner for vehicles which can reduce intake noise can be implement | achieved, reducing the engine output fall and the bad influence on driving | running | working feeling.

1 is a left side view of a motorcycle according to the present embodiment. 1 is a top view of a motorcycle according to the present embodiment. 1 is a rear view of a motorcycle according to the present embodiment. FIG. 3 is a top view illustrating a state in which a fitting component such as a vehicle body cover is removed in FIG. 2. It is a top view which shows the structure of the air cleaner periphery for vehicles which concerns on this Embodiment. It is a perspective view of the periphery of the vehicle air cleaner which concerns on this Embodiment. It is the upper side figure and rear view of the air cleaner for vehicles which concern on this Embodiment. It is a side view of the air cleaner for vehicles concerning this embodiment. It is a perspective view of the air cleaner for air cleaner vehicles concerning this embodiment. It is sectional drawing which follows the AA line of FIG. It is a schematic diagram which shows the vibration state of a rear panel.

  Hereinafter, the present embodiment will be described in detail with reference to the accompanying drawings. In the following, an example in which the fuel supply device according to the present invention is applied to an off-road motorcycle will be described, but the present invention is not limited to this and can be modified as appropriate. For example, the present invention can be applied to other types of motorcycles such as an on-road type and a scooter type.

  With reference to FIGS. 1 to 3, a schematic configuration of the entire motorcycle 1 according to the present embodiment will be described. FIG. 1 is a left side view of a motorcycle 1 according to the present embodiment. FIG. 2 is a top view of the motorcycle 1 according to the present embodiment. FIG. 3 is a rear view of the motorcycle 1 according to the present embodiment. In the following description, the front of the vehicle is indicated by an arrow FR, the rear of the vehicle is indicated by an arrow RE, the left side of the vehicle is indicated by L, and the right side of the vehicle is indicated by R.

  As shown in FIGS. 1 to 3, the motorcycle 1 includes a body frame 11 made of steel or aluminum alloy on which various parts such as a power unit and an electrical system are mounted. The main frame 12 of the vehicle body frame 11 branches leftward and rightward from the head pipe 13 located at the front end, and extends obliquely downward. A swing arm bracket 14 extends downward from the rear end of the main frame 12. The down tube 15 of the body frame 11 extends from the head pipe 13 substantially downward. From the lower end of the down tube 15, a lower tube 16 branched left and right extends substantially horizontally toward the rear, and is connected to the lower end of the swing arm bracket 14.

  A water-cooled engine 21 serving as a driving source is mounted in a space surrounded by the body frame 11. A radiator 22 that dissipates the cooling water in the engine 21 is disposed in front of the engine 21. A fuel tank 23 in which fuel is stored is disposed above the engine 21, and a seat 31 is disposed behind the fuel tank 23. The seat 31 is supported by a seat rail 17 that extends rearward and upward from the rear portion of the main frame 12. A subframe 18 that supports the seat rail 17 in an auxiliary manner is connected between the rear end portion of the seat rail 17 and the swing arm bracket 14.

  A vehicle air cleaner 24 that filters air in the atmosphere is disposed in a space surrounded by the seat rail 17 and the subframe 18 (see FIG. 6). Both side surfaces of the vehicle air cleaner 24 are partially covered by a pair of left and right side covers 35. The side cover 35 is fixed to the seat rail 17 and the subframe 18. A footrest 55 is provided below the seat 31. A shift pedal 56 is provided in front of the footrest 55 on the left side of the vehicle body, and a brake pedal 57 for the rear wheel 61 is provided in front of the footrest 55 on the right side of the vehicle body.

  A front fork 72 is supported on the front upper side of the vehicle body frame 11 via a steering shaft provided in the head pipe 13 so as to be steerable. The front fork 72 has a suspension for cushioning the front wheels. A handle bar 73 is provided at the upper end of the steering shaft, and grips 74 are attached to both ends of the handle bar 73. A clutch lever 75 is provided on the handle bar 73 on the left side of the vehicle body, and a brake lever 76 for the front wheel 71 is disposed on the handle bar 73 on the right side of the vehicle body. A front wheel 71 is rotatably supported at the lower portion of the front fork 72. The front wheel 71 is provided with a brake disc 77 and a caliper 78 that constitute a brake. An upper portion of the front wheel 71 is covered with a front fender 79 provided on the front fork 72.

  A swing arm 62 is connected to the swing arm bracket 14 of the vehicle body frame 11 so as to be able to swing in the vertical direction. Yes. A rear wheel 61 is rotatably supported at the rear portion of the swing arm 62. A driven sprocket 64 is provided on the left side of the rear wheel 61, and a drive chain 66 is bridged between the driven sprocket 64 and the drive sprocket 65 on the engine 21 side. The rear wheel 61 is provided with a brake disk (not shown) and a caliper 67 that constitute a brake. The upper portion of the rear wheel 61 is covered with a rear fender 68 disposed behind the seat 31.

  The engine 21 includes a horizontal crank type four-cycle single cylinder engine (for example, 450 cc) and a transmission. Air is taken into the engine 21 through a throttle body (not shown), and the fuel and air injected by the fuel injection device are mixed and supplied to the combustion chamber. The exhaust gas after combustion is exhausted from the muffler 27 via an exhaust pipe 26 extending rearward on the right side surface of the engine 21.

  Next, the configuration around the vehicle air cleaner 24 of the motorcycle 1 will be described with reference to FIGS. 4 to 6. FIG. 4 is a top view showing the vehicle air cleaner in which the fuel tank 23, the seat 31, the side cover 35, and the like are removed from the motorcycle 1 according to the present embodiment, and FIG. 5 is a partial view of FIG. It is an enlarged view. FIG. 6 is a perspective view of the periphery of the vehicle air cleaner 24 when viewed from the rear right side of the motorcycle 1. 4 and 5 show a state in which some components such as the fuel tank 23 and the seat 31 are omitted for convenience of explanation (see FIG. 1). FIG. 6 shows a state in which some parts such as the rear fender 68 and the side cover 35 are omitted.

  As shown in FIGS. 4 to 6, the vehicle air cleaner 24 is disposed between the engine 21 and the rear wheel 61 in a top view, and is disposed directly under the seat 31 in a side view (see FIG. 1). ). The vehicle air cleaner 24 has a substantially triangular air cleaner box 241 in a side view. The air cleaner box 241 is attached to the seat rail 17 and the subframe 18 with the apex of a substantially triangle facing downward in a side view. The upper surface of the air cleaner box 241 is open, and the upper surface of the air cleaner box 241 is covered with the sheet 31.

  A wall surface on the vehicle front side of the air cleaner box 241 is configured by a front panel 243 having a substantially circular opening 243a. The front panel 243 partitions the vehicle air cleaner 24 into an upstream dirty side and a downstream clean side of the air intake path. An element 242 (see FIGS. 7 to 9) for filtering the air sucked into the air cleaner box 241 is attached to the front panel 243 so as to cover the opening 243a. The vehicle air cleaner 24 filters the air taken from the upper surface side of the air cleaner box 241 through the element 242 and supplies the air to the throttle body (not shown) via the throttle body (not shown).

  Wall surfaces on both sides in the vehicle width direction of the air cleaner box 241 are configured by side panels 244 having a substantially triangular shape in a side view. The upper part of the side panel 244 is cut away so as to form an opening X between the side panel 244 and the seat rail 17. The opening X serves as an air inlet of the vehicle air cleaner 24.

  A wall surface on the vehicle rear side of the vehicle air cleaner 24 is constituted by a rear panel 245 that also serves as a part of the tire house of the rear wheel 61. The rear panel 245 has a curved surface portion 245 a that is curved so as to avoid contact with the rear wheel 61. By providing the curved surface portion 245a, contact between the rear wheel 61 and the rear panel 245 can be avoided even when the swing arm 62 swings and the rear wheel 61 and the vehicle air cleaner 24 approach each other. Thus, the vehicle air cleaner 24 ensures the maximum capacity while avoiding a collision with the rear wheel 61 by the curved surface portion 245a of the rear panel 245. The rear panel 245 is fixed to a fixing portion 18a provided on each of the pair of left and right subframes 18 with a screw member.

  By the way, in a general motocrosser, a vehicle air cleaner is disposed in the vicinity of the engine behind the engine in order to reduce the intake resistance to the engine. In such a motocrosser, a single-cylinder engine with a relatively large displacement is used, so that the intake sound from the engine has a high sound pressure in a low frequency region that easily passes through the air cleaner box. For this reason, when the rear panel of the vehicle air cleaner is made of a general-purpose resin material (for example, polypropylene), the intake sound from the engine is likely to be transmitted to the outside of the vehicle air cleaner through the rear panel.

  In particular, when the area of the rear panel is large, the rear panel vibrates due to engine intake pulsation or engine vibration, and the rear panel functions like a speaker to expand the intake sound and radiate it as intake noise. For this reason, even when talc material is added to the wall surface of the air cleaner box to improve the rigidity, it is difficult to sufficiently reduce the intake sound transmitted through the vehicle air cleaner unless the wall thickness is increased. Further, when the rear panel also serves as a rear wheel tire house, it is difficult to ensure the rigidity of the wall surface by providing ribs or the like on the surface of the rear panel.

  Therefore, in the present embodiment, the rear panel 245 having a larger area than the front panel 243 and the side panel 244 in the vehicle air cleaner 24 is made of a highly rigid material. With this configuration, vibration of the rear panel 245 based on intake air pulsation or the like of the engine 21 can be prevented, and intake sound radiated to the outside through the vehicle air cleaner 24 can be reduced. Hereinafter, the configuration of the vehicle air cleaner 24 will be described in detail.

  Next, the configuration of the vehicle air cleaner 24 according to the present embodiment will be described in detail with reference to FIGS. 7 to 9. FIG. 7 is a top view and a rear view of the vehicle air cleaner 24 according to the present embodiment. FIG. 8 is a side view of the vehicle air cleaner 24 according to the present embodiment, and FIG. 9 is a perspective view of the vehicle air cleaner 24 according to the present embodiment as viewed from the rear side.

  As shown in FIGS. 7 to 9, the vehicle air cleaner 24 is configured by disposing an element 242 in an air cleaner box 241 having an open upper surface. The air cleaner box 241 and the outlet tube 246 are partitioned by a front panel 243. The air cleaner box 241 is a dirty side on the upstream side of the air suction path, and the outlet tube 246 is a clean side on the downstream side of the air suction path.

  The front panel 243 has a substantially rectangular plate shape, and has a substantially circular opening 243a (see FIGS. 4 and 5) that communicates the air cleaner box 241 and the outlet tube 246 at the center. The front panel 243 is provided with a fixture (not shown) so as to straddle the opening 243a. By fixing a fixing portion (not shown) of the element 242 to the fixing tool, the element 242 is attached so as to cover the opening 243a. The vehicle air cleaner 24 sucks air from the air cleaner box 241 on the dirty side via the element 242, filters the sucked air through the element 242, and discharges it to the outlet tube 246 on the clean side.

  The air cleaner box 241 includes a front panel 243, a pair of side panels 244, and a rear panel 245. Each side panel 244 is formed of a general-purpose resin material, and has a substantially triangular shape in a side view as described above. The oblique side 244a on the front side of each side panel 244 is fastened to the side of the front panel 243 by rivets.

  The rear panel 245 is formed of a highly rigid material, and is curved so as to be away from the front panel 243 from below to above. The lower side portion of the rear panel 245 is fastened to the lower side portion of the front panel 243 by a rivet 244b. Both side portions of the rear panel 245 are fastened to the oblique sides on the rear side of the pair of side panels 244 by rivets 244b. A mounting recess 245c for receiving an insert nut 19 (see FIG. 10) for fixing the vehicle air cleaner 24 to the subframe 18 is formed on both left and right ends of the rear panel 245. The mounting recess 245c has a through hole 245b. Is provided.

  The outlet tube 246 is formed of rubber or a general-purpose resin material, and is formed in a tubular shape so as to reduce the passage resistance of the air suction path. One end side of the outlet tube 246 is formed to have a large diameter to match the opening 243a of the front panel 243, and the opening 246a on the other end side of the outlet tube 246 is formed to have a small diameter to match the throttle body (not shown). Has been. The outlet tube 246 connects the air cleaner box 241 and the throttle body so as to reduce the diameter from one end side to the other end side.

  The high-rigidity material used for the rear panel 245 is not particularly limited as long as the rigidity of the rear panel 245 can be improved. As the highly rigid material, it is preferable to use a carbon fiber composite material (CFRP: Carbon Fiber Reinforced Plastics) using a lightweight resin or a resin base material from the viewpoint of preventing an increase in the weight of the vehicle air cleaner 24. As the carbon fiber composite material, one formed by impregnating a carbon sheet with a resin, or one obtained by mixing carbon fiber into a resin pellet and injection molding can be used. Since these carbon fiber composite materials have higher rigidity than general-purpose resin materials, a sufficient noise reduction effect can be obtained. Among these, from the viewpoint of productivity and production cost of the vehicle air cleaner 24, a pellet type that can be produced by the same injection molding method as that of the general-purpose resin material is preferable.

  When a carbon fiber composite material is used as the highly rigid material, it is preferable to use a material having a flexural modulus of 8 GPa or more. If the flexural modulus of the carbon fiber composite material is 8 GPa or more, vibration of the rear panel 245 (permeation of intake sound) based on intake pulsation of the engine 21 or the like can be prevented, and intake noise can be reduced. Examples of the carbon fiber composite material having a flexural modulus of 8 GPa or more include those having a carbon fiber content of 10% by weight or more.

  Resin pellets include polyamide resin (PA resin), polypropylene resin (PP resin), acrylonitrile / butadiene / styrene resin (ABS resin), polybutylene terephthalate resin (PBT resin), thermoplastic polyurethane resin (TPU resin) and polyphenylene sulfide. Resin (PPS resin) etc. are mentioned.

  Specific examples of the carbon fiber composite material include long fiber reinforced resin (trade name: Plastron (registered trademark) PP-CF 30%, PA-CF 20%, PA-CF 30%, manufactured by Daicel Polymer Co., Ltd.). . Moreover, it may replace with what mixed carbon fiber in the resin pellet, and what mixed glass fiber in the resin pellet may be used.

  By the way, when the rear panel 245 of the vehicle air cleaner 24 of the motorcycle 1 is made of a carbon fiber composite material, electrolytic corrosion (galvanic corrosion) occurs due to a potential difference between the carbon fiber exhibiting conductivity and a metal such as aluminum. Hereinafter, a configuration example of the vehicle air cleaner 24 that can suppress electrolytic corrosion will be described.

  10 is a cross-sectional view taken along line AA in FIG. In the example shown in FIG. 10, the rear panel 245 is provided with a through hole 245b of the mounting recess 245c at a position corresponding to the through hole 18b of the fixed portion 18a. The mounting recess 245c accommodates an iron insert nut 19 (mounting member). The rear panel 245 is fixed to an aluminum alloy fixing portion 18 a via the insert nut 19. By fixing in this way, a clearance between the rear panel 245 and the fixing portion 18a is secured.

  Further, the potential difference between the iron constituting the insert nut 19 and the carbon fiber composite material constituting the rear panel 245 is smaller than the potential difference between the carbon fiber composite material and the aluminum alloy constituting the subframe 18. For this reason, electrolytic corrosion of the rear panel 245 based on the potential difference between the rear panel 245 and the subframe 18 is prevented. In the present embodiment, the iron insert nut 19 is used as the mounting member, but the present invention is not limited to this configuration. The attachment member may be formed of a material in which the potential difference with the carbon fiber is smaller than the potential difference between the carbon fiber and the aluminum alloy.

  Next, with reference to FIG. 11, the relationship between the configuration of the rear panel and the intake noise will be described in detail by comparing the vehicle air cleaner according to the comparative example with the vehicle air cleaner according to the present embodiment. FIG. 11A is a schematic diagram of a vehicle air cleaner 500 according to a comparative example, and FIG. 11B is a schematic diagram of a vehicle air cleaner 24 according to the present embodiment. In FIG. 11A and FIG. 11B, the same components are denoted by the same reference numerals.

  As shown in FIG. 11A, in the vehicle air cleaner 500 according to the comparative example, the rear panel 501 is made of a general-purpose resin material. For this reason, the intake sound from the engine 21 acts on the rear panel 501 having a large area via the throttle body, the intake pipe (not shown), and the outlet tube 246. The rear panel 501 vibrates due to the intake air pulsation of the engine 21 and radiates the intake noise by expanding the intake sound like a speaker.

  On the other hand, as shown in FIG. 11B, in the vehicle air cleaner 24 according to the present embodiment, the rear panel 245 is made of a highly rigid material. For this reason, the vibration of the rear panel 245 due to the intake air pulsation of the engine 21 can be reduced. As a result, the intake noise is shielded by the rear panel 245, so that the intake noise radiated from the vehicle air cleaner 24 is reduced.

  As described above, according to the vehicle air cleaner 24 according to the above-described embodiment, the rigidity of the rear panel 245 of the air cleaner box 241 is improved by the high-rigidity material. Vibration can be reduced. As a result, the transmission of the intake noise through the air cleaner box 241 is suppressed, the intake noise is reduced, and the adverse effect on the output reduction of the engine 21 and the running feeling can be reduced without increasing the intake resistance.

  In particular, in the above-described embodiment, it is possible to obtain a sufficient noise reduction effect simply by configuring the rear panel 245 where loads due to intake noise to the vehicle air cleaner 24 are concentrated with a highly rigid material. In addition, since the intake noise can be reduced simply by configuring the rear panel 245 from a highly rigid material, there is no need to provide ribs or the like on the rear panel 245, and the shape of the air cleaner box is not complicated. As a result, it is possible to prevent the mud from being attached to the wall surface during the traveling due to the complicated structure of the rear panel 245 and the deterioration of workability such as the cleaning in the air cleaner box 241 and the element 242 replacement. Moreover, since the airflow supplied to the engine 21 is not disturbed, the influence on the output of the engine 21 can be minimized.

  In the above embodiment, the intake noise can be reduced simply by replacing the rear panel 245 of the air cleaner box 241 from a general-purpose resin material to a high-rigidity material. Therefore, the weight increment is only the specific gravity of the general-purpose resin material and the high-rigidity resin material Thus, the weight increment of the vehicle air cleaner 24 can be kept low. Further, since it is not necessary to use an expensive high-rigidity material over a wide area, it is excellent in cost effectiveness. Further, since the conventional manufacturing apparatus for the rear panel 245 can be used as it is, the rear panel 245 can be easily manufactured.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  For example, in the above embodiment, the example in which the rear panel 245 of the vehicle air cleaner 24 is configured using a high-rigidity material has been described, but the present invention is not limited to this configuration. The highly rigid material may be used for at least one wall surface of the vehicle air cleaner 24. For example, the front panel 243 and the side panel 244 may be made of a highly rigid material.

  Moreover, in the said embodiment, although the air cleaner box 241 demonstrated the example which has four wall surfaces (The front panel 243, the side panel 244, and the rear panel 245), it is not limited to this structure. The air cleaner box 241 may have a box shape that takes in air from the outside.

  Moreover, in the said embodiment, although the structure which does not provide a reinforcement rib in the vehicle air cleaner 24 was demonstrated, it is not limited to this structure. Reinforcing ribs may be provided on the rear panel 245 to improve rigidity. In this case, the shape of the reinforcing rib and the installation location of the reinforcing rib are not particularly limited. In particular, in the present embodiment, since the rigidity of the rear panel 245 is enhanced by a high rigidity material for the rear panel 245, the installation range of the reinforcing ribs can be suppressed to the extent that the performance of the vehicle air cleaner 5 is not affected. . For example, the reinforcing rib may be provided so that the height decreases from the outer edge portion of the rear panel 245 toward the center portion. As a result, the rigidity of the rear panel 245 can be further improved while securing the detachability of the element, and intake noise can be further reduced.

  Further, when the rear panel 245 is made of a carbon fiber composite material, the surface of the rear panel 245 may be subjected to a surface treatment such as embossing. Thereby, the embossing from the component surface of the carbon fiber material can be made inconspicuous.

  Moreover, in the said embodiment, although the structure which fixes the air cleaner 24 for vehicles to the fixing | fixed part 18a of the sub-frame 18 via the iron insert nut 19 was demonstrated, the material which comprises the insert nut 19 is limited to iron. Not. The insert nut 19 may be made of any material that can prevent the carbon fiber from being corroded.

  INDUSTRIAL APPLICABILITY The present invention has an effect that intake noise can be reduced while reducing adverse effects on engine output reduction and running feeling, and is particularly effective as a vehicle air cleaner for off-road type competition vehicles.

1 Motorcycle 19 Insert nut (mounting member)
24 Vehicle Air Cleaner 241 Air Cleaner Box 242 Element 243 Front Panel (Wall Surface)
244 Side panel (wall surface)
245 Rear panel (wall surface)
245a Curved portion 246 Outlet tube 246a Opening

Claims (5)

In a vehicle air cleaner that includes an air cleaner box having a plurality of wall surfaces and purifies air supplied to an engine,
In the air cleaner box, at least one of the wall surfaces is made of a highly rigid material.   The vehicle air cleaner according to claim 1, wherein the wall surface made of the highly rigid material is a wall surface on the vehicle rear side.   The vehicle air cleaner according to claim 1, wherein the high-rigidity material is a carbon fiber composite material containing carbon fibers.   A wall surface made of the carbon fiber composite material is fixed to an aluminum alloy body frame via an attachment member, and a potential difference between the attachment member and the carbon fiber composite material is determined between the carbon fiber composite material and the body frame. The vehicle air cleaner according to claim 3, wherein the vehicle air cleaner is smaller than the potential difference. The vehicle air cleaner according to any one of claims 1 to 4, wherein a rib that reinforces the wall surface is provided on the wall surface made of the highly rigid material.

Images