JP7208856B2 - Air intake duct drainage structure - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drainage structure for an intake duct that extends in the longitudinal direction of a straddle-type vehicle and supplies air to an engine.

BACKGROUND ART Straddle-type vehicles such as motorcycles have an intake duct that extends in the longitudinal direction of the vehicle body and supplies air to the engine (for example, Patent Document 1). Air introduced into the air intake duct is supplied to the engine after being filtered by elements in the air intake duct.

Japanese Patent No. 5898776

In the air intake duct disclosed in Patent Document 1, there is a risk that rainwater and the like may enter the air intake duct through the opening at the front end of the vehicle while the vehicle is running. Therefore, it is necessary to prevent such rainwater from entering the element.

SUMMARY OF THE INVENTION An object of the present invention is to provide a draining structure for an air intake duct of a straddle-type vehicle that can effectively prevent water from entering an element.

In order to achieve the above object, a draining structure for an intake duct according to the present invention is a draining structure for an intake duct extending in the front-rear direction of a saddle-ride type vehicle for supplying air to an engine, wherein an intake passage is formed therein. and an element arranged in the duct body for filtering air flowing through the intake passage, the element being inclined forward and upward with respect to a horizontal plane, and the element in the intake passage. A downstream portion of the upstream portion is formed with an upwardly sloping passage portion sloping upwardly toward the element, and a draining opening is formed in the rear wall of the upwardly sloping passage portion.

According to this configuration, since the air flows from bottom to top toward the element, it is possible to effectively prevent water from entering the element. The water separated from the air is discharged to the outside through the drainage opening.

In the present invention, a downwardly inclined passage portion may be formed upstream of the upwardly inclined passage portion for guiding air downward toward the upwardly inclined passage portion. According to this configuration, the air flows downward toward the element and then upward, thereby promoting gas-liquid separation. As a result, it is possible to more effectively prevent water from entering the element.

When the downwardly inclined passage portion is formed, the upper wall of the intake passage on the upstream side of the element is smoothly recessed downward from the downwardly inclined passage portion to the upwardly inclined passage portion to release the air downward. A deflection recess may be formed for deflecting to and then deflecting upward. According to this configuration, the air smoothly flows from the bottom to the top toward the element, thereby promoting gas-liquid separation.

In the present invention, a clean passage downstream of the element in the intake passage may protrude upward from the element, be curved and inclined downward, and then extend rearward. According to this configuration, since the air passing through the element is smoothly guided rearward, the intake efficiency is kept high.

In this case, a reservoir space communicating with the drain opening is formed behind the upwardly inclined passage portion and below the downwardly inclined portion of the clean passage, and a discharge hole is formed in the bottom wall of the reservoir space. good too. According to this configuration, the air intake duct can be made large by the size of the storage space. This increases the rigidity of the intake duct, and the space can be used, for example, to support the duct or to support other components in the duct.

When the storage space is formed, an engaging projection extending inward in the vehicle width direction may be formed on the duct body, and the engaging projection may be formed on a wall of the storage space in the duct body. . According to this configuration, when the vehicle overturns, the portion of the storage space is preferentially damaged. Since the part where the storage space is formed is the area where the intake passage is not formed, even if the part is damaged, the intake air can be supplied to the engine, and the running can be continued.

The present invention may further include a cover body detachably attached to the duct body and covering the duct body from the outside, and the element may be covered with the cover body from the outside. According to this configuration, by removing the cover body, the element can be replaced without removing the duct main body, so the element can be easily replaced. In addition, the duct main body and the cover body can accentuate the appearance, thereby improving the degree of freedom in setting the design.

According to the drain structure for the air intake duct of the straddle-type vehicle of the present invention, air flows from bottom to top toward the element, so that it is possible to effectively prevent water from entering the element.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side view showing a front portion of a motorcycle, which is a kind of straddle-type vehicle, provided with a draining structure for an intake duct according to the first embodiment of the present invention; It is a top view which shows the front part of the same two-wheeled motor vehicle. Fig. 2 is a plan view showing an intake system of the same motorcycle; It is a side view which shows the intake duct of the same motorcycle. It is a side view which shows the duct main body of the same air intake duct. It is a downward perspective view which shows the inner half body of the same duct main body. It is a top view which shows the same air intake duct.

Preferred embodiments of the present invention will be described below with reference to the drawings. In this specification, "right" and "left" refer to "right" and "left" as seen from the driver in the vehicle. "Upstream" and "downstream" refer to the upstream side and the downstream side in the flow direction of intake air.

FIG. 1 is a side view of a motorcycle, which is a type of straddle-type vehicle, provided with a water drain structure for an intake duct according to a first embodiment of the present invention. The body frame FR of the straddle-type vehicle of this embodiment has a main frame 1 forming a front half and a rear frame 2 forming a rear half. The rear frame 2 is connected to the rear portion of the main frame 1 .

A front fork 6 is rotatably supported by a head pipe 4 at the front end of the main frame 1 via a steering shaft (not shown). A front wheel 8 is attached to the lower end of the front fork 6 . A handle 10 is attached to the upper end of the front fork 6 .

A swing arm bracket 12 is provided at the rear end of the main frame 1 . A front end of a swing arm 14 is supported by the swing arm bracket 12 so as to be vertically swingable. A rear wheel (not shown) is attached to the rear end of the swing arm 14 .

An engine E, which is a driving source, is mounted below the main frame 1 and in front of the swing arm bracket 12 . Rear wheels (not shown) are driven by the engine E via a power transmission member (not shown) such as a chain.

The engine E of this embodiment is a parallel four-cylinder engine. However, the type of engine E is not limited to this. The engine E has a crankcase 16 that rotatably supports a crankshaft 15 , a cylinder block 18 projecting upward from the crankcase 16 , and a cylinder head 20 attached to the top of the cylinder block 18 . The cylinder axis C1 of the engine E of the present embodiment extends upward with a slight forward incline.

A fuel tank 22 is arranged on the upper part of the main frame 1, and a seat 24 on which an operator sits is attached to the rear frame 2. - 特許庁A front cowl 25, which is a kind of resin cowling, is attached to the front part of the vehicle body. The front cowl 25 of this embodiment has an upper cowl portion 26 that covers the front of the head pipe 4, and a pair of left and right shroud portions 28 that extend rearward from the lower portion of the upper cowl portion 26 and cover the front forks 6 from the outside. there is However, the configuration of the cowling (front cowl) 25 is not limited to this.

An exhaust port 20a is formed on the front surface of the cylinder head 20, and an intake port 20b is formed on the rear surface. An exhaust pipe 30 is connected to the exhaust port 20a. After extending downward in front of the engine E, the exhaust pipe 30 extends rearward under the engine E and is connected to an exhaust muffler (not shown).

An air intake duct 32 for supplying air A in front of the engine E to the engine E as intake air is arranged on the left side of the vehicle body. The air intake duct 32 has a front end 32 a that opens forward, and a rear end 32 b that is connected to a supercharger 34 arranged in the cylinder block 18 . In other words, the supercharger 34 constitutes an intake intake section provided behind the cylinder block 18 and supported by the engine E. As shown in FIG. In this embodiment, since the engine is a supercharged engine, the supercharger 34 constitutes the intake air intake portion. Configure the intake section.

An intake chamber 36 is arranged downstream of the turbocharger 34 and the turbocharger 34 and the intake chamber 36 are connected. The intake chamber 36 stores high pressure air HA pressurized by the supercharger 34 . The intake chamber 36 extends in the longitudinal direction from above the supercharger 34 to above the cylinder block 18 and the cylinder head 20 . A relief valve 35 shown in FIG. 3 is attached to the front surface of the intake chamber 36 . The relief valve 35 opens when the pressure inside the intake chamber 36 exceeds a predetermined value, and excess air (high pressure air) HA inside the intake chamber 36 is returned to the intake duct 32 through the relief passage 37 .

As shown in FIG. 1, the intake chamber 36 and the intake port 20b are connected via a throttle body 38. As shown in FIG. The throttle body 38 includes a throttle valve (not shown) inside and adjusts the amount of intake air supplied to the engine E. Since the intake chamber 36 is arranged above the cylinder head 20, the intake passage inside the throttle body 38 extends substantially vertically. This realizes a downdraft structure.

The air intake duct 32 includes a duct body 40 in which an air intake passage IP is formed, and a cover body 42 that covers the front half of the duct body 40 from the outside. The intake duct 32 further includes a cleaner unit 44 arranged in the front half of the duct body 40 . The cleaner unit 44 is provided with an element 45 that filters the air A flowing through the intake passage IP. The intake passage IP is partitioned by an element 45 into a primary side (upstream) dirty passage DP and a secondary side (downstream) clean passage CP. The cleaner unit 44 is also covered with the cover body 42 from the outside. A cap 47 is attached to the front end of the duct body 40 .

As shown in FIG. 2, the duct main body 40 extends in the vehicle width direction outside (left side) of the vehicle body frame FR and the engine E in the front-rear direction. In the present embodiment, the front end 32a of the intake duct 32 is located outside the upper cowl portion 26. As shown in FIG. However, the position of the front end 32a is not limited to this.

As shown in FIG. 3, the duct body 40 has a left and right split structure, and has a left outer duct half body 40L and a right inner duct half body 40R. The outer duct half 40L and the inner duct half 40R are connected by a plurality of bolts 46. As shown in FIG. The duct body 40 of this embodiment is, for example, polypropylene (PP) or nylon 6 (PA6). However, the material of the duct body 40 is not limited to this.

A front end portion of the duct body 40 shown in FIG. 1 is detachably attached to the vehicle body by a first fastening member 48 mounted from the outside. In this embodiment, the front end of the duct body 40 is attached to a cowling (front cowl) 25 supported by the vehicle body frame FR. That is, the front end portion of the duct body 40 is indirectly attached to the vehicle body frame FR. However, the front end portion of the duct body 40 may be directly attached to the vehicle body frame FR.

The first fastening member 48 is, for example, a bolt. In this embodiment, the front end portion of the duct body 40 is attached to the vehicle body by two first fastening members 48 arranged vertically. However, the number and arrangement of the first fastening members 48 are not limited to this.

On the other hand, the rear end portion of the duct body 50 is attached to the intake air intake portion (supercharger 34) by means of three second fastening members 50 arranged in the circumferential direction. The second fastening member 50 is, for example, a bolt. However, the number and arrangement of the second fastening members 50 are not limited to this.

FIG. 5 is a side view showing a state in which the cover body 42 is removed from the intake duct 32. FIG. As shown in the figure, a first bolt insertion hole 52 facing in the vehicle width direction is formed in the front end portion of the duct body 40 . Two first bolt insertion holes 52 are provided side by side in the vertical direction. The first fastening member 48 ( FIG. 1 ) is inserted into the first bolt insertion hole 52 . Specifically, a rubber nut (not shown) is attached to the first bolt insertion hole 52 and a mounting hole (not shown) formed in the front cowl 25 from the outside in the vehicle width direction, and the first fastening member 48 is attached to the rubber nut. Tighten from the outside in the width direction. As described above, the front end portion of the duct body 40 is attached to the vehicle body.

The first bolt insertion hole 52 is formed in the inner duct half 40R on the inner side in the vehicle width direction. As shown in FIG. 7, the front edge 40La of the outer duct half 40L on the outside in the vehicle width direction is receded rearward from the front edge 40Ra of the inner duct half 40R. Therefore, in the side view of FIG. 5, the first bolt insertion hole 52 is exposed outward. That is, the first bolt insertion hole 52 can be visually recognized from the outside. This improves the operability from the outside.

A second bolt insertion hole 54 facing the vehicle width direction is formed in the rear end portion of the duct body 40 . Three second bolt insertion holes 54 are provided side by side in the circumferential direction. The second fastening member 50 ( FIG. 1 ) is inserted into the second bolt insertion hole 54 . Specifically, the second fastening member 50 is inserted through the second bolt insertion hole 54 from the outside in the vehicle width direction, and is fastened to a screw hole (not shown) formed in the supercharger 34 from the outside in the vehicle width direction. As described above, the rear end portion of the duct body 40 is attached to the supercharger 34 .

The second bolt insertion hole 54 is formed in the inner duct half 40R on the inner side in the vehicle width direction. More specifically, three flange portions 55 are formed radially protruding from the rear end of the inner duct half 40R, and a second bolt insertion hole 54 is formed in each flange portion 55 . In this embodiment, the flange portion 55 extends upward, downward and rearward from the rear end of the inner duct half 40R. As a result, the second bolt insertion hole 54 is exposed outward when viewed from the side. That is, the second bolt insertion hole 54 can be visually recognized from the outside. Therefore, operability from the outside is improved.

A first screw hole 56 facing the vehicle width direction is formed in the longitudinally intermediate portion of the duct body 40 . The first screw hole 56 is formed in the outer duct half 40L on the outer side in the vehicle width direction. The first screw hole 56 is, for example, an insert nut. A cleaner opening 58 into which the cleaner unit 44 is inserted is formed in the outer duct half 40L. The cleaner opening 58 is a rectangular opening elongated in the front-rear direction. The cleaner opening 58 is formed forward of the first screw hole 56 in the front half of the outer duct half 40L.

A second screw hole 60 facing the vehicle width direction is formed in the vicinity of the cleaner opening 58 in the outer duct half 40L. In this embodiment, the second screw holes 60 are provided one each on the front side and the rear side of the cleaner opening 58 . The second screw hole 60 is, for example, an insert nut. A cap engaging piece 62 extending forward is formed on the front edge of the duct body 40 . The cap engagement piece 62 is formed on each of the outer duct half 40L and the inner duct half 40R.

The aforementioned cap 47 is attached to the cap engaging piece 62 . As shown in FIG. 4 , the cap 47 has a filter 64 that prevents foreign matter from entering the intake duct 32 . The filter 64 consists of a seal portion 65 and a wire mesh 66 . The seal portion 65 is made of rubber, for example, and constitutes the outer frame of the filter 64 . A groove (not shown) is formed in the back surface (rear surface) of the seal portion 65 , and by fitting the groove of the seal portion 65 into the cap engaging piece 62 of the duct body 40 from the front, the cap 47 is attached to the duct body 40 . can be attached to

A wire mesh 66 is provided so as to block the opening at the front end of the intake duct 32, and traps foreign matter larger than the mesh. This prevents foreign matter from entering the intake passage IP in the intake duct 32 . The cap 47 is obliquely attached to the front-rear direction. Specifically, since the front edge of the outer duct half 40L is set back behind the front edge of the inner duct half 40R, the wire mesh 66 is arranged so as to incline outward toward the rear. As a result, the appearance is improved and the surface area of the wire mesh 66 can be increased. In this embodiment, the head portion 48a of the first fastening member 48 is exposed outward when the cap 47 is removed.

The cover body 42 shown in FIG. 1 covers the front half of the duct body 40 from the outside. The cover body 42 is an integrally molded product made of resin with an open inside. The cover body 42 is, for example, an acrylonitrile-butadiene-styrene copolymer synthetic resin (ABS resin). However, the material of the cover body 42 is not limited to this. In this embodiment, as shown in FIG. 4 , the first fastening member 48 , the cleaner unit 44 and the sealing portion 65 on the outer periphery of the cap 47 are covered with the cover body 42 from the outside.

The cover body 42 is detachably attached to the duct body 40 with a third fastening member 68 . Specifically, the front end of the cover body 42 is inserted into the seal portion 65 of the cap 47 from the front, and the rear end of the cover body 42 is attached to the duct body 40 with a third fastening member 68 . The third fastening member 68 is inserted through a third bolt insertion hole 69 formed in the cover body 42 and fastened to the first screw hole 56 ( FIG. 5 ) of the duct body 40 .

The cleaner unit 44 is arranged in the front half of the duct body 40 . Here, the front half portion of the duct body 40 refers to a region forward of the middle portion of the duct body 40 in the front-rear direction. In this embodiment, the cleaner unit 44 is arranged below the handle 10 in FIG. Since the cleaner unit 44 is not arranged behind the cylinder block 18 and outside the supercharger 34, a part of the supercharger 34 can be visually recognized in a side view.

As shown in FIG. 5, the cleaner unit 44 is detachably attached to the duct body 40 by a fourth fastening member 70 from the outside. FIG. 6 is a side view of the inner duct half 40R with the outer duct half 40L removed from the duct body 40 of FIG. 4, that is, the inner duct half 40R. As shown in the figure, the cleaner unit 44 has a lid-integrated element 45 . That is, the element 45 is fitted in the frame 72 made of resin. Element 45 is, for example, a sponge. However, the element 45 is not limited to this. In this embodiment, the duct body 40 also serves as a cleaner case.

A third bolt insertion hole 72 a is formed in the frame 72 . Two third bolt insertion holes 72 a are provided corresponding to the second screw holes 60 ( FIG. 5 ) of the duct body 40 . The element 45 of the cleaner unit 44 is inserted into the cleaner opening 58 of the duct body shown in FIG. In this state, the fourth fastening member 70 is inserted through the third bolt insertion hole 72 a of the cleaner unit 44 from the outside and is tightened to the second screw hole 60 of the duct body 40 .

As shown in FIG. 6, which is a perspective view from below, the inner duct half 40R may be provided with guides 75 for guiding and holding the cleaner unit 44 as it is inserted into the cleaner opening 58 (FIG. 5). The element 45 is arranged in a posture inclined forward and upward with respect to the horizontal plane, that is, in a posture inclined downward toward the rear.

An upwardly inclined passage portion 76 that is inclined upward toward the element 45 is formed in the downstream portion of the upstream side portion (dirty passage DP) of the element 45 in the intake passage IP. Furthermore, a downwardly inclined passage portion 78 that guides air downward toward the upwardly inclined passage portion 76 is formed on the upstream side of the upwardly inclined passage portion 76 .

Specifically, the upper wall of the intake passage IP on the upstream side of the element 45 is smoothly recessed downward from the lower inclined passage portion 78 to the upper inclined passage portion 76 to deflect the air downward and then upward. A deflection recess 80 is formed to allow the Further, the rear wall 82 of the upper inclined passage portion 76 is inclined upward while smoothly curving rearward. A drain opening 84 is formed in the rear wall 82 of the upwardly inclined passage portion 76 . In this embodiment, the drain opening 84 is an elongated rectangular slit-like through hole. However, the drain opening 84 is not limited to this, and may be, for example, a circular opening.

The air A that has flowed in from the opening at the front end of the intake duct 32 flows downward through the downwardly inclined passage portion 78, flows upwardly through the upwardly inclined passage portion 76, and then passes through the element 45 that is inclined forward and upward. . In this manner, the air A passes through the element 45 from bottom to top, thereby promoting gas-liquid separation and suppressing the inflow of moisture into the element 45 . The separated water is discharged through drain openings 84 in rear wall 82 .

A clean passage CP on the downstream side of the element 45 in the intake passage IP protrudes upward from the element 45, further curves, inclines downward, and then extends rearward. A secondary air outlet 86 opening in the vehicle width direction is formed in the clean passage CP. The outlet 86 is formed in the inner duct half 40R and arranged slightly downstream of the element 45 in the clean passage CP. A secondary air introduction passage 88 shown in FIG. 3 is connected to the outlet 86 to introduce air into the exhaust pipe 30 of the engine E.

A blow-off introduction port 90 opening in the vehicle width direction is formed in the clean passage CP in FIG. In this embodiment, the blow-off inlet 90 is formed in the inner duct half 40R and arranged downstream of the outlet 86 in the clean passage CP. The relief passage 37 shown in FIG. 3 is connected to the blow-off inlet 90 , and surplus air HA inside the intake chamber 36 is returned to the intake duct 32 through the relief passage 37 .

A blow-by pipe 92 is connected to the rear end of the duct body 40 shown in FIG. The blow-by pipe 92 returns the blow-by gas BG leaking from the crankcase 16 and the cylinder block 18 shown in FIG.

In this embodiment, since the element 45 is arranged in the front half of the intake duct 32, the clean passage CP is enlarged. By increasing the size of the clean passage CP, the degree of freedom in arranging the secondary air outlet 86 and the blow-off inlet 90 is increased, and the secondary air introduction passage 88 and the relief passage 37 connected to these are increased. The degree of freedom in the placement of is also increased.

As shown in FIG. 6, a storage space SP is formed behind the upwardly inclined passage portion 76 of the dirty passage DP and in regions below and in front of the clean passage CP. The storage space SP communicates with the dirty passage DP through the drain opening 84, but is not the intake passage IP through which the air A flows. A discharge hole 85a is formed in the bottom wall 85 of the storage space SP.

As shown in FIG. 7, the duct body 40 is formed with an engaging projection 94 extending inward in the vehicle width direction. The engagement projection 94 extends inward in the vehicle width direction from the inner side surface in the vehicle width direction of the inner duct half 40R. In the present embodiment, the engaging projection 94 extends inward in the vehicle width direction while being inclined rearward in plan view of FIG. 7 .

The engagement projection 94 has a projecting portion 96 extending inward in the vehicle width direction from the inner surface of the duct body 40 in the vehicle width direction, and an engaging portion 98 provided at the tip of the projecting portion 96 . The engaging portion 98 of the present embodiment is a substantially conical projection, and is engaged with the engaged portion 100 formed on the vehicle body shown in FIG.

In this embodiment, a bracket 102 is fixed to the vehicle body frame FR, and an engagement hole 102a is formed in the bracket 102 . A cylindrical rubber damper 104 is attached to the engagement hole 102 a , and the engagement portion 98 of the engagement projection 94 is fitted into the hollow hole of the rubber damper 104 . That is, the bracket 102 constitutes the engaged portion 100 that is engaged with the engaging portion 98 .

As shown in FIG. 7, the engaging projection 94 is formed in the front-rear direction intermediate portion of the duct body 40 . Also, the engaging projection 94 is formed in a region of the duct body 40 where the intake passage IP is not formed. Specifically, the engagement protrusion 94 is formed on the inner wall of the storage space SP.

As shown in FIG. 2, the engaging projection 94 is formed on the vehicle width direction inner wall of the portion OS of the intake duct 32 that is the outermost portion of the vehicle body. For example, if the vehicle rolls over while parked, the outermost portion OS of the intake duct 32 contacts the ground. At that time, a load received from the ground acts on the engagement protrusion 94 . The inner wall of the storage space SP is preferentially damaged by the load received by the engaging projection 94 . However, since the storage space SP does not constitute the intake passage IP, the supply of the air A to the engine E is not hindered, so the vehicle can run.

Next, a procedure for attaching the air intake duct 32 to the vehicle body will be described. First, the outer duct half 40L and the inner duct half 40R are connected by a plurality of bolts 46 shown in FIG. Next, as shown in FIG. 3, the engaging protrusion 94 of the duct body 40 is engaged with the engaging hole 102a of the bracket 102 fixed to the body frame FR via the rubber damper 104. Next, as shown in FIG. Thereby, the air intake duct 32 is positioned on the vehicle body. At this time, the secondary air introduction passage 88 and the relief passage 37 are connected to the secondary air outlet 86 and the blow-off introduction port 90 , respectively, and the blow-by pipe 92 is connected to the rear end of the duct body 40 .

In this state, the front end portion of the duct body 40 shown in FIG. Thereby, the duct body 40 is attached to the vehicle body.

Next, a cap 47 is attached to the front end of the intake duct 32 shown in FIG. The cap 47 is inserted from the front into the cap engaging piece 62 at the front end of the intake duct 32 . Furthermore, the cleaner unit 44 of FIG. 6 is attached to the duct main body 44 . Specifically, the cleaner unit 44 is inserted into the cleaner opening 58 and the frame 72 is attached to the duct body 40 by the fourth fastening member 70 .

Next, the cover body 42 shown in FIG. 4 is attached to the duct main body 40 . Specifically, the cover body 42 is inserted into the duct body 40 and the cap 47 from the front, and the front end of the cover body 42 is engaged with the duct body 40 and the cap 47 . In this state, the front end portion of the cover body 42 is attached to the duct main body 40 by the third fastening member 68 . The cover body 42 covers the first fastening member 48 and the cleaner unit 44 from the outside and fixes the cap 47 .

Next, a replacement procedure for the element 45 will be described. First, the third fastening member 68 is loosened and the cover body 42 is removed. Next, the fourth fastening member 70 shown in FIG. 5 is loosened and the cleaner unit 44 is removed. The cleaner unit 44 after cleaning or a new cleaner unit 44 is attached to the duct body 40 by the procedure described above, and the cover body 42 is attached to the duct body 40 by the procedure described above. Thus, in this embodiment, by operating one third fastening member 68 in FIG. 4, the cover body 42 can be removed and the cleaner unit 44 can be accessed.

Next, the flow of intake air in this embodiment will be described. When the engine E starts, air A flows into the intake passage IP from the opening at the front end of the intake duct 32 shown in FIG. The air A flowing into the intake passage IP flows downward through the downward inclined passage portion 78 and upward through the upward inclined passage portion 76 and then passes through the element 45 . After the air A flows while changing its direction up and down, it flows upward from the bottom toward the element 45, thereby promoting gas-liquid separation. Thereby, it is possible to suppress the inflow of moisture into the element 45 . The separated water flows into the storage space SP through the drainage opening 84 of the rear wall 82 and is discharged to the outside through the discharge holes 85a of the storage space SP.

The air A that has passed through the element 45 flows rearward and downward through the clean passage CP and is sucked into the supercharger 34 shown in FIG. Air pressurized by the supercharger 34 is stored in an intake chamber 36 and supplied to the engine E via a throttle body 38 . When the pressure in the intake chamber 36 increases, the relief valve 35 in FIG. 3 opens, and excess air HA in the intake chamber 36 is returned to the clean passage CP through the relief passage 37 and the blow-off inlet 90 .

Further, air is introduced into the exhaust pipe 30 of the engine E from the secondary air outlet 86 through the secondary air introduction passage 88 . As a result, the unburned hydrocarbons contained in the exhaust gas are completely burned. Further, the blow-by gas BG leaking from the crankcase 16 and the cylinder block 18 is returned to the clean passage CP inside the intake duct 32 through the blow-by pipe 92 shown in FIG. The blow-by gas BG returned to the clean passage CP is sucked into the supercharger 34 together with the air A.

According to the above configuration, the cleaner unit 44 can be replaced without removing the duct body 40 by operating the third fastening member 68 shown in FIG. 1 to remove the cover body 42 . Therefore, replacement of the element 45 is easy. In addition, since the duct main body 40 can be attached and detached by fastening and loosening the first fastening member 48 and the second fastening member 50 from the same outside direction, the workability of attaching and detaching the duct body 40 is also good. Furthermore, the duct main body 40 and the cover body 42 can accentuate the appearance, thereby improving the degree of freedom in setting the design. Moreover, since the first fastening member 48 at the front end of the duct body 40 is hidden by the cover body 42, the appearance of the vehicle is improved.

A cleaner unit 44 shown in FIG. 5 is detachably attached to the duct body 40 by a fourth fastening member 70 extending from the outside. As a result, the cleaner unit 44 can be easily removed from the outer side of the vehicle body. Therefore, replacement of the element 45 is easy.

As shown in FIG. 4 , a cap 47 is attached to the front end portion of the duct body 40 and the outer peripheral portion of the cap 47 is covered with the cover body 42 . As a result, since the cover body 42 can be used for fixing the cap 47, the number of parts can be reduced.

Also, when the cap 47 is removed, the head portion 48a of the first fastening member 48 is exposed outward. As a result, the fastening and loosening work of the first fastening member 48 can be performed from the outside of the vehicle body, so that the duct main body 40 can be easily attached and detached.

An intake duct 32 is connected to a supercharger 34 shown in FIG. Since the intake duct 32 is directly connected to the supercharger 34 in this manner, the supercharger 34 is not covered from the outside by other equipment such as an air cleaner, and a part of the supercharger 34 is can be exposed outward. Therefore, by constructing the supercharger 34 as a design part, it is possible to improve the appearance. Further, since the element 45 is arranged in the front half of the air intake duct 32, a large capacity clean passage CP from the supercharger 34 to the element 45 can be formed upstream of the supercharger 34.

As shown in FIG. 6, a secondary air outlet 86 and a blow-off inlet 90 are formed in the clean passage CP. As shown in FIG. 3, the intake duct 32 passes outside the engine, so the engine E and the intake duct 32 are close to each other. Therefore, the relief passage 37 and the secondary air introduction pipe 88 can be shortened.

As shown in FIG. 6, an engaging projection 94 extending inward in the vehicle width direction is formed in a region (storage space SP) of the duct body 40 where the intake passage IP is not formed. The engaging projection 94 is engaged with an engaged portion 100 formed on the vehicle body shown in FIG. As a result, when the duct body 40 is attached, it can be positioned by the engaging protrusions 94, so workability is good. Also, when the vehicle rolls over, the portion where the engaging projection 94 is formed is preferentially damaged. Since the portion where the engaging projection 94 is formed is a region where no intake passage is formed, even if the portion is damaged, the supply of air to the engine E is not hindered and the running can be continued.

As shown in FIG. 6, since the air A flows upward toward the element 45, it is possible to effectively prevent water from entering the element 45. As shown in FIG. Water separated from the air A is discharged to the outside through the drainage opening 84 .

Furthermore, the air A flows downward toward the element 45 and then upward due to the downwardly inclined passage portion 78 and the upwardly inclined passage portion 76 on the upstream side of the element 45, thereby promoting gas-liquid separation. As a result, it is possible to more effectively prevent water from entering the element 45 .

In addition, the deflection unit smoothly recesses downward from the lower inclined passage portion 78 to the upper inclined passage portion 76 in the upper wall on the upstream side of the element 45 in the intake passage IP to deflect the air downward and then upward. A recess 80 is formed. As a result, the air A smoothly flows upward toward the element 45, thereby further promoting gas-liquid separation.

A clean passage CP projects upwardly from the element 45, further curves and slopes downwardly and then extends rearwardly. As a result, the air A that has passed through the element 45 is smoothly guided rearward, thereby maintaining a high intake efficiency.

A storage space SP communicating with the drain opening 84 is formed behind the upwardly inclined passage portion 76 and below the downwardly inclined portion of the clean passage CP, and a discharge hole 85a is formed in the bottom wall 85 of the storage space SP. ing. As a result, the intake duct 32 can be made larger by the size of the storage space SP. Therefore, the rigidity of the air intake duct 32 is increased, and the space SP can be used, for example, to support the duct or to support other parts on the duct. As a result, the degree of freedom in design is improved.

The present invention is not limited to the above embodiments, and various additions, changes, or deletions are possible without departing from the scope of the present invention. For example, in the above embodiment, an example in which the air intake duct draining structure of the present invention is applied to a motorcycle has been described, but the air intake duct draining structure of the present invention can also be applied to straddle-type vehicles other than motorcycles. Accordingly, such are also included within the scope of this invention.

32 Intake duct 40 Duct main body 42 Cover body 45 Element 76 Upper inclined passage portion 78 Lower inclined passage portion 80 Deflection concave portion 82 Rear wall 84 Drain opening 85a Discharge hole 94 Engagement protrusion A Air CP Clean passage E Engine IP Intake passage SP Storage space

Claims (6)

A draining structure for an intake duct extending in the longitudinal direction of a straddle-type vehicle and supplying air to an engine,
a duct body having an intake passage formed therein; and an element arranged in the duct body for filtering air flowing through the intake passage;
a cover body detachably attached to the duct body and covering the duct body from the outside ,
The element is arranged to tilt forward and upward with respect to a horizontal plane,
an upwardly inclined passage portion inclined upward toward the element is formed at a downstream portion of the upstream portion of the element in the intake passage,
A drain opening is formed in the rear wall of the upwardly inclined passage portion,
A drainage structure for an air intake duct , wherein the element is covered from the outside by the cover body . 2. A draining structure for an intake duct according to claim 1, wherein a downwardly inclined passage portion for guiding air downward toward said upwardly inclined passage portion is formed upstream of said upwardly inclined passage portion. 3. The drain structure according to claim 2, wherein the upper wall of the intake passage on the upstream side of the element is smoothly recessed downward from the lower inclined passage portion to the upper inclined passage portion to deflect air downward. A draining structure for an air intake duct, in which a deflecting concave portion is formed to deflect upward from the air intake duct. 4. The drain structure according to any one of claims 1 to 3, wherein a clean passage on the downstream side of the element in the intake passage protrudes upward from the element, further curves and slopes downward and then extends rearward. Drainage structure for the extended intake duct. A draining structure for an intake duct extending in the longitudinal direction of a straddle-type vehicle and supplying air to an engine ,
a duct body having an intake passage formed therein; and an element arranged in the duct body for filtering air flowing through the intake passage,
The element is arranged to tilt forward and upward with respect to a horizontal plane,
an upwardly inclined passage portion inclined upward toward the element is formed at a downstream portion of the upstream portion of the element in the intake passage ,
A drain opening is formed in the rear wall of the upwardly inclined passage portion,
a clean passage on the downstream side of the element in the intake passage protrudes upward from the element, further curves and slopes downward, and then extends rearward;
A storage space communicating with the drain opening is formed behind the upwardly inclined passage portion and below the downwardly inclined portion of the clean passage,
A drainage structure for an intake duct, wherein a discharge hole is formed in the bottom wall of the storage space. The drain structure according to claim 5, wherein the duct body is formed with an engaging projection extending inward in the vehicle width direction,
A drainage structure for an air intake duct, wherein the engaging projection is formed on a wall of the storage space in the duct body.

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