JP2014034285A - Ram duct unit and motor cycle including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ram duct unit which inhibits peeling of a sound absorption member and improve the yield.SOLUTION: A ram duct unit 1 includes: a ram duct 21; a sound absorbing sponge 23; and a ring 24. The ram duct 21 forms an intake passage 25 for guiding air to an engine E. The sound absorbing sponge 23 is adhered along an inner surface part of the ram duct 21. The ring 24 is a linear member extending on a plane arranged perpendicular to an air flow direction and is formed so that a dimension measured in the flow direction becomes short, and presses at least a front end part of the sound absorbing sponge 23 against the inner surface part of the ram duct 21.

Description

  The present invention relates to a ram duct unit for introducing outside air into an engine, and a motorcycle including the same.

  A motorcycle is provided with a ram duct in the front portion of the vehicle body. The ram duct is connected to the combustion chamber of the engine via an air cleaner, and external air taken in as combustion air for the engine is supplied to the engine via the air cleaner. Since the ram duct generates intake noise when taking in outside air, a sound absorbing member is attached to the inner surface of the ram duct. However, the sound absorbing member may peel off from the inner surface of the ram duct when the motorcycle travels at a high speed and receives strong traveling wind. As a ram duct unit capable of preventing such a sound absorbing member from peeling off, for example, a ram duct unit described in Patent Document 1 is known.

  The ram duct unit of Patent Document 1 has a net-like holder formed in accordance with the shape of the inner surface of the ram duct, and is configured to press the entire surface of the sound absorbing member against the inner surface of the ram duct. Thereby, peeling of a sound absorption member can be prevented.

JP 2010-95245 A

  The shape of the ram duct is formed by three-dimensionally combining irregularities and curves, and the shape is complicated. In the ram duct unit described in Patent Document 1, a holder having such a complicated shape must be formed in a net shape. Therefore, high dimensional accuracy is required at the time of forming the holder, and the yield of the ram duct unit is lowered. On the other hand, if the dimensional accuracy is lowered to improve the yield, the sound absorbing member cannot be uniformly pressed against the inner surface of the ram duct by the holder, and the sound absorbing member may be peeled off from the inner surface of the ram duct.

  Then, this invention aims at providing the ram duct unit which can suppress peeling of a sound absorption member and can improve a yield.

  The ram duct unit of the present invention includes a ram duct that forms an intake passage that guides air to an engine, a sound absorbing member that is attached along an inner surface of the ram duct that defines the intake passage, and the sound absorbing member. A pressing member that presses at least the upstream end of the ram duct against the inner surface of the ram duct, and the pressing member extends on a plane perpendicular to the air flow direction so that the dimension in the flow direction is shortened. It is formed by existing linear members.

  According to the present invention, since the upstream end of the sound absorbing member is pressed against the inner surface of the ram duct by the pressing member, the sound absorbing member is peeled off due to the air introduced into the ram duct even if the pressing member is a linear member. Can be prevented. In addition, since the pressing member is a linear member, the shape of the pressing member can be simplified even if the ram duct is formed in a three-dimensional shape in which unevenness and curves are three-dimensionally combined. Therefore, peeling of the sound absorbing member can be suppressed and the yield can be improved.

  In the above invention, the pressing member may be formed in an annular shape in accordance with the shape of the inner surface portion of the ram duct, and the inner surface portion of the upstream end portion of the sound absorbing member may be pressed against the inner surface portion of the ram duct over the entire circumferential direction. Good.

  According to the above configuration, since the pressing member is formed in an annular shape, it is easy to make the pressing member, and deformation of the pressing member can be suppressed.

  In the above invention, the inner surface of the ram duct may be formed with a plurality of locking portions spaced apart from each other in the circumferential direction, and the pressing member may be fitted and positioned in the locking portion. .

  If the said structure is followed, since the pressing member is positioned by the latching | locking part, it can prevent that the position of a pressing member shifts | deviates by the air introduce | transduced. Thereby, peeling of the sound absorption member accompanying the position shift of a pressing member can be prevented.

  In the above invention, at least three or more locking portions may be formed on the inner surface of the ram duct.

  If the said structure is followed, since the three or more latching | locking parts are formed, it can prevent that a pressing member rotates. Thereby, tilting of a pressing member can be prevented and peeling of the sound absorption member accompanying tilting of a pressing member can be prevented.

  In the above invention, the inner surface portion of the ram duct has a linear inner surface portion extending in a vertical direction perpendicular to the flow direction, and the linear inner surface portion includes one of the plurality of locking portions. The fitting groove portion may be formed, and the fitting groove portion may extend along the vertical direction and be formed in a long shape.

  If the said structure is followed, since the fitting groove part which latches a pressing member is formed in elongate, it can prevent that a pressing member rotates. Thereby, tilting of a pressing member can be prevented and peeling of the sound absorption member accompanying tilting of a pressing member can be prevented.

  In the above invention, the plurality of locking portions are formed on an inner surface portion of the ram duct and include a protruding portion that protrudes from the inner surface portion of the ram duct to the inside of the ram duct, and the protruding portion is inserted into the sound absorbing member. A through hole may be formed.

  If the said structure is followed, positioning can be performed also in the part by which the sound absorption member is arrange | positioned between a pressing member and a ram duct.

  In the above invention, on the upstream side of the ram duct, an intake port portion for taking in air is formed, and on the inner surface portion of the ram duct, a recessed portion for arranging the sound absorbing member is formed, and the recessed portion is The sound absorbing member may be formed so that the inner surface of the sound absorbing member is flush with the inner surface of the intake port portion or closer to the inner surface portion of the ram duct than the inner surface of the intake port portion.

  According to the above configuration, since the inner surface of the sound absorbing member is flush with the inner surface of the intake port portion or closer to the inner surface portion of the ram duct than the inner surface of the intake port portion, the sound absorbing member is closer to the intake passage than the inner surface of the intake port portion. Protruding to the side can be prevented. As a result, the intake resistance of the intake passage can be reduced, and it is possible to prevent the sound absorbing member from being peeled off due to air hitting the upstream end surface of the sound absorbing member.

  In the above invention, the ram duct is formed with a resonance chamber that communicates with the intake passage, and has an isolation wall that separates the intake passage and the resonance chamber, and the isolation wall is a part of an inner surface portion of the ram duct. The sound absorbing member may be attached to a region of the inner surface portion of the ram duct excluding the isolation wall.

  According to the above configuration, since the resonance chamber is formed on the opposite side through the isolation wall of the intake passage, the intake noise transmitted from the intake passage to the isolation wall can be attenuated in the resonance chamber. Thereby, transmission of intake noise can be suppressed by the resonance chamber without attaching a sound absorbing member to the isolation wall. That is, noise in the ram duct unit can be reduced without attaching a sound absorbing member to the isolation wall.

  Further, by removing the isolation wall from the region where the sound absorbing member is attached, the position of the isolation wall can be moved toward the intake passage by the thickness of the sound absorbing member as compared to the case where the isolation wall is attached. As a result, the volume of the resonance chamber can be increased, and the degree of freedom in selecting the frequency band of the intake noise to be attenuated can be expanded.

  The motorcycle according to the present invention includes any of the ram duct units described above.

  According to the present invention, it is possible to provide a motorcycle that exhibits the effects described above.

  According to the present invention, peeling of the sound absorbing member can be suppressed and the yield can be improved.

It is a right view which shows a motorcycle provided with the ram duct unit which is one Embodiment of this invention. Fig. 2 is a front view of a ram duct unit provided in the motorcycle of Fig. 1. FIG. 3 is a cross-sectional view showing the ram duct unit of FIG. 2 cut along a cutting line III-III. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. It is sectional drawing cut | disconnected and shown by the cutting line VV of FIG. It is an expanded sectional view which expands and shows the latching | locking part periphery of the ram duct unit of FIG. FIG. 2 is an exploded view showing the ram duct unit of FIG.

  Hereinafter, a motorcycle 2 including a ram duct unit 1 according to an embodiment of the present invention will be described with reference to the drawings. In addition, the concept of the direction used in the following description is based on the direction seen from the driver riding on the motorcycle 2. Further, the ram duct unit 1 and the motorcycle 2 described below are only one embodiment of the present invention. Therefore, the present invention is not limited to the embodiments, and additions, deletions, and changes can be made without departing from the spirit of the invention.

[Motorcycle]
FIG. 1 is a right side view of a motorcycle 2 including a ram duct unit 1 according to the first embodiment of the present invention. As shown in FIG. 1, the motorcycle 2 includes a vehicle body 3, a front wheel 4, and a rear wheel 5. The front wheel 4 is rotatably supported by a lower end portion of a front fork 6 that extends substantially in the vertical direction. The front fork 6 is supported by a steering shaft (not shown) via an upper bracket (not shown) provided at the upper end portion thereof and an under bracket (not shown) provided below the upper bracket. Yes. The steering shaft is rotatably supported by the head pipe 7. A handle 8 is attached to the upper bracket.

  The handle 8 extends from the upper bracket in the vehicle width direction (that is, in the left-right direction) so that the driver can grip the vicinity of both ends of the handle 8 with both hands. A throttle grip 8a is provided near the right end of the handle 8 at a portion gripped by the driver's right hand. The throttle grip 8a is configured to be rotatable about the axis of the handle 8 and will be described later. The throttle device 14 moves in conjunction with the rotation of the throttle grip 8a. The handle 8 is connected to the steering shaft via an upper bracket and an under bracket, and the steering shaft can be rotated in the head pipe 7 by rotating the handle 8. In the motorcycle 2, the front wheel 4 can be turned in a desired direction by rotating the steering shaft by rotating the handle 8.

  In addition, a pair of left and right main frames 9 are integrally provided on the head pipe 7 constituting a part of the vehicle body 3. The pair of left and right main frames 9 extends rearward while being slightly inclined downward from the head pipe 7, and a pair of left and right pivot frames 10 are connected to the rear end portion of the main frame 9. The pivot frame 10 pivotally supports a front end portion of a swing arm 11 extending substantially in the front-rear direction, and a rear wheel 5 is rotatably supported by the rear end portion of the swing arm 11. A fuel tank 12 is placed on the pair of main frames 9 behind the head pipe 7, and a seat 13 for riding a driver is provided behind the fuel tank 12.

  Further, as shown in FIG. 1, a parallel four-cylinder engine E is mounted on the main frame 9 and the pivot frame 10 below the fuel tank 12 and between the front wheels 4 and the rear wheels 5. ing. A transmission (not shown) is connected to the engine E, and a driving force output from the transmission is transmitted to the rear wheel 5 via a chain (not shown). A throttle device 14 disposed inside the main frame 9 is connected to an intake port (not shown) of the engine E. The ram duct unit 1 is connected to the upstream side of the throttle device 14 via an air cleaner 15 and a head block 16 disposed below the fuel tank 12. The ram duct unit 1 is connected to the engine E using traveling wind pressure from the front F. It is configured to take in outside air (air).

  The ram duct unit 1 is provided in a front portion of the vehicle body 3, and the front portion of the vehicle body 3 is covered with a front cowl 17. The front cowl 17 is formed in a substantially U shape in a plan view, and covers the front end portion of the vehicle body 3 from the front F at its front end portion. The front cowl 17 has a pair of headlamps 18 formed at the front end of the vehicle body 3. The pair of headlamps 18 are arranged symmetrically with respect to the center line of the vehicle body 3, and an intake port 19 is formed at the center position thereof. The intake port 19 is formed in a substantially triangular shape when viewed from the front, and is connected to the ram duct unit 1. The ram duct unit 1 is adapted to take in outside air through the intake port 19, and the taken-in outside air is guided to the throttle device 14 through the head block 16 and the air cleaner 15. Thus, the ram duct unit 1 that takes in outside air is configured to suppress intake noise when taking in outside air. Hereinafter, the configuration of the ram duct unit 1 will be specifically described with reference to FIGS.

[Ram duct unit]
The ram duct unit 1 has a ram duct 21 as shown in FIG. The ram duct 21 is a duct for sending outside air (air) taken in from the intake port 19 to the head block 16 at the rear, and the taken outside air flows backward in the ram duct 21. The ram duct 21 is formed in a substantially T shape in a side view, and has a main body 21a and a resonator box 21b. As shown in FIG. 2, the main body 21a is formed in a substantially cylindrical shape, and has a funnel shape with a width that decreases toward the rear. The cross section of the main body 21a (specifically, the cross section perpendicular to the flow direction of air flowing in the main body 21a (that is, substantially the front-rear direction)) has a generally trapezoidal shape that tapers downward. An intake passage 25 defined by the inner surface portion is formed in the main body 21a having such a shape. As shown in FIG. 3, the intake passage 25 extends substantially in the front-rear direction, and a cross section of the intake passage 25 (specifically, a cross section perpendicular to the flow direction) tapers downward in a generally trapezoidal shape. (See also FIG. 5 described later).

  As shown in FIG. 1, the opening end on the rear side of the main body 21 a is fixed to the head block 16, and the intake passage 25 is connected to the inside of the head block 16. On the other hand, the opening end 21 d on the front side of the main body 21 a is fixed to the front cowl 17 so as to surround the attachment port 19, and the intake passage 25 is connected to the intake port 19 by being fixed. As shown in FIGS. 2 and 3, a screen 22 is fitted into the opening end 21d on the front side of the main body 21a. The screen 22 is a so-called wire mesh, and prevents foreign matter taken together with outside air from the intake port 19 from entering the intake passage 25. In the main body 21 a fixed in this way, air is taken in from the opening end 21 d on the front side via the intake port 19, and the air is sent to the head block 16 through the intake passage 25. The foreign matter contained in the taken-in air is removed by the screen 22 when passing through the intake passage 25.

  Further, the main body 21 a has an isolation wall 26 in the middle part in the front-rear direction of the lower surface part that is a part of the inner surface part that defines the ventilation passage 25. The isolation wall 26 is formed in a substantially flat plate shape, and forms a linear inner surface portion in the inner surface portion of the main body 21a. A resonator box 21 b is integrally provided on the lower surface of the isolation wall 26. The resonator box 21b is formed in a substantially bottomed rectangular tube shape, and is formed so that the front and rear wall portions thereof spread to the front side and the rear side, respectively. The resonator box 21b having such a shape is fixed to the isolation wall 26 so as to close the opening, and a resonator chamber 27 is formed in the resonator box 21b where the opening is closed. . The resonator chamber 27 is separated from the intake passage 25 by a separating wall 26, and a connecting pipe 28 is provided in the separating wall 26.

  The connection pipe 28 is formed in a substantially cylindrical shape. The connecting pipe 28 vertically penetrates the isolation wall 26, and connects the resonator chamber 27 and the intake passage 25. As a result, it is possible to resonate and cancel noise of a specific frequency among noises of various frequencies included in the intake noise generated in the intake passage 25, and to prevent the intake noise from leaking out of the ram duct 21. The connection pipe 28 can adjust the frequency of noise to be resonated by changing its diameter and length, and the diameter and length of the connection pipe 28 can be freely set.

  As shown in FIGS. 4 and 5, in the inner surface portion of the main body 21a defining the intake passage 25, the left side portion, the upper side portion, and the right side portion of the front-rear direction intermediate region 21c are open end portions 21d on the front side of the intermediate region 21c. And it is dented outside the inner surface part of the opening end part of the rear side. As a result, a substantially U-shaped attachment groove 29 is formed on the inner surface of the main body 21a, and a sound absorbing sponge 23 for suppressing intake noise is disposed in the attachment groove 29 which is a recess. 2, 3, 4, and 5, the sound absorbing sponge 23 is indicated by a dot pattern in order to clearly indicate the sound absorbing sponge 23.

  The sound absorbing sponge 23 which is a sound absorbing member is a sponge made of a sound absorbing material, and can reduce noise in a wide range of frequencies as well as a specific frequency like the resonator chamber 27. The sound absorbing sponge 23 is formed in a substantially U shape substantially matching the shape of the mounting groove 29, and is adhered along the left side, the upper side and the right side of the inner surface of the main body 21a with an adhesive, an adhesive tape or the like. It is attached. That is, the sound absorbing sponge 23 is affixed to a region excluding the part of the isolation wall 26 in the front-rear direction intermediate portion of the inner surface of the main body 21a.

  The thickness of the sound absorbing sponge 23 attached in this way is such that the inner surface of the front end portion (upstream end portion) of the sound absorbing sponge 23 is flush with the inner surface of the opening end portion 21d (intake port portion) on the front side of the main body 21a. Thus, it is possible to prevent the air flowing through the intake passage 25 from hitting the front end portion of the sound absorbing sponge 23 and raising it, and the intake resistance of the intake passage 25 from being increased. The inner surface of the front end portion of the sound absorbing sponge 23 does not necessarily need to be flush with the inner surface of the opening end portion 21d on the front side, and the inner surface of the front end portion of the sound absorbing sponge 23 is outside the inner surface of the opening end portion 21d on the front side. That is, you may be located in the inner surface part side of the front-back direction intermediate | middle area | region 21c of the main body 21a. As a result, as in the case of the flushing, the rising of the sound absorbing sponge 23 and the increase in the intake resistance of the intake passage 25 can be prevented. Further, in order to prevent the front end portion of the sound absorbing sponge 23 from rising, a ring 24 is provided on the main body 21a.

  The ring 24 that is a pressing member has a main body portion 31, a plurality of protruding pieces 32, and a pin portion 33. The main body 31 is formed by extending a linear member having a circular cross section made of a synthetic resin such as PEP resin on one plane and forming it in an annular shape. The main body 31 formed in this way is erected perpendicular to the flow direction so that the linear member extends on a plane perpendicular to the flow direction of the air passing through the intake passage 25, and its thickness ( The dimension in the flow direction is thin. In addition, the outer shape of the main body 31 is formed in accordance with the shape of the inner surface of the main body 21a, and is substantially trapezoidal when viewed from the front. That is, the main body 31 is formed in a substantially trapezoidal shape by connecting four linear portions of an upper portion 31a, a left portion 31b, a lower portion 31c, and a right portion 31d.

  In the main body 31 having such a shape, a plurality of protruding pieces 32 are formed on the left side portion 31b and the right side portion 31d of the four straight portions at intervals, and in this embodiment, the left side portion Four protruding pieces 32 are formed on 31b and the right portion 31d, respectively. The protruding pieces 32 protrude outward from the left portion 31b and the right portion 31d (that is, the left and right sides), respectively, and their tips are formed in a sharp shape so as to be caught by the sound absorbing sponge 23. Thereby, the position shift of the sound absorbing sponge 23 with respect to the ring 24 is prevented. In addition, a pair of pin portions 33 are formed on the left portion 31b and the right portion 31d, respectively. The pin portion 33 is formed in a substantially cylindrical shape, and protrudes outward (ie, left side and right side) from the left side portion 31b and the right side portion 31d of the main body portion 31, respectively. On the other hand, as shown in FIG. 6, projecting portions 41 are formed on the inner surface portion of the main body 21 a of the ram duct 21 at positions corresponding to the pair of pin portions 33, respectively.

  The protruding portion 41 is formed in a substantially cylindrical shape, and protrudes from the left and right side portions of the inner surface toward the inside of the main body 21a. The sound-absorbing sponge 23 has a pair of through-holes 23c, and the pair of through-holes 23c are formed so as to correspond to the pair of protrusions 41, respectively. The protrusion 41 is inserted through the through hole 23c of the sound absorbing sponge 23, and the inner hole 41a of the protrusion 41 is exposed to the inside. The inner hole 41a of the protruding portion 41 is formed so that the pin portion 33 can be inserted, and the ring 24 can be locked and positioned by inserting the pin portion 33 into the inner hole 41a of the protruding portion 41. Yes. Thus, the sound absorbing sponge 23 is inserted between the inner peripheral portion of the main body 31 and the ring 24 by inserting the protruding portion 41 into the through hole 23 c of the sound absorbing sponge 23 and inserting the pin portion 33 into the protruding portion 41. The ring 24 can be positioned even at the intervening portion.

  The height of the protruding portion 41 having such a positioning function is lower than the thickness of the sound absorbing sponge 23, and the inner surface of the sound absorbing sponge 23 is hidden so that the front end surface of the protruding portion 41 is hidden by the sound absorbing sponge 23 in the front view. It is located lower (that is, on the inner surface side of the main body 21a). Further, the outer dimension of the ring 24 is formed to be larger than the inner dimension of the sound absorbing sponge 23. Therefore, the ring 24 can be sunk in the sound absorbing sponge 23, and the ring 24 can press the entire circumferential direction of the front end portion of the sound absorbing sponge 23 against the inner surface of the main body 21a. Thereby, it is possible to prevent the front end portion of the sound absorbing sponge 23 from rolling up.

  Furthermore, the inner dimension of the ring 24 is the same as or larger than the inner dimension of the sound absorbing sponge 23, and the difference between the height of the protrusion 41 and the thickness of the sound absorbing sponge 23 is the same as the thickness of the linear member of the ring 24 or It is bigger than that. As a result, the entire upper part 31a, left part 31b and right part 31d of the main body 31 of the ring 24 can be submerged in the sound absorbing sponge 23, and they are hidden by the sound absorbing sponge 23 in a front view. Thereby, since the protrusion from the sound absorbing sponge 23 can be eliminated, the resistance of the intake passage 25 can be reduced.

  Further, as shown in FIG. 6, an engaging groove 41 b extending in the vertical direction is formed on the tip surface of the protruding portion 41 that locks the ring 24. The cross section of the engagement groove portion 41b is formed in an arc shape, and a part of the left side portion 31b and the right side portion 31d of the main body portion 31 of the ring 24 is fitted into the engagement groove portion 41b to be engaged. In this way, by engaging the ring 24 with the engagement groove 41b, the ring 24 can be prevented from being tilted around the pin 33. Further, in order to prevent the ring 24 from tilting, a fitting groove portion 42 is also formed in the isolation wall 26 of the ram duct 21.

  The isolation wall 26 is formed flat including the tip portion, and constitutes the straight inner surface portion of the main body 21a of the ram duct 21 as described above. The fitting groove portion 42 that is a locking portion is formed at the distal end portion of the isolation wall 26, and the fitting groove portion 42 is formed according to the shape of the lower portion 31 c of the ring 24. That is, the fitting groove portion 42 is linearly formed so as to extend in the left-right direction, like the lower portion 31 c of the ring 24. Since the lower portion 31c of the ring 24 is fitted and locked in the fitting groove portion 42, the ring 24 can be positioned and the tilt of the ring 24 can be prevented.

  Further, the fitting groove 42 is formed on the front side of the resonator box 21 b in the isolation wall 26. Accordingly, it is not necessary to increase the thickness of the isolation wall 26 in order to prevent the portion of the fitting groove 42 from protruding into the resonator chamber 27, and the volume of the resonator chamber 27 can be prevented from decreasing. Further, the depth of the fitting groove 42 is deeper than the thickness of the lower portion 31 c of the ring 24. Therefore, the lower portion 31 c of the main body 31 is also hidden in the fitting groove 42 in front view. Thereby, since the protrusion from the isolation wall 26 can be eliminated, the resistance of the intake passage 25 can be reduced.

  Thus, on the inner surface of the main body 21a of the ram duct 21, a pair of protruding portions 41 and fitting groove portions 42, which are locking portions, are formed on the left side surface, the right side surface, and the bottom surface, respectively. That is, the three locking portions 41 and 42 are formed on the inner surface portion of the main body 21a of the ram duct 21 with a space therebetween. As described above, since the three locking portions 41 and 42 are arranged at intervals, the ring 24 can be positioned so as not to be tilted by the three locking portions 41 and 42. Thereby, the position shift and tilt of the ring 24 due to the air taken into the ram duct 21 can be prevented, and the sound absorbing sponge 23 can be prevented from peeling off due to the position shift and tilt of the ring 24.

  As shown in FIG. 7, the ram duct 21 is configured to be divided into right and left along the center plane of the ram duct 21 (corresponding to the plane including the cutting line III-III in FIG. 2). The ram duct 21 can be assembled by combining the right portion 52. Similarly, the sound absorbing sponge 23 is also configured to be divided into right and left along the center plane, and the parts 23 a and 23 b of the divided sound absorbing sponge 23 are attached to the parts 51 and 52 of the ram duct 21 before assembly. It has been.

  The portions 51 and 52 of the ram duct 21 are combined so that the portions 24 a and 23 b of the sound absorbing sponge 23 are attached thereto, and then the ring 24 is interposed therebetween. At this time, the lower portion 31c of the ring 24 is placed in a fitting groove portion 42 extending in the left-right direction, and the lower portion 31c is slid rightward or leftward along the fitting groove portion 42, thereby each portion 51 of the ram duct 21. , 52 are brought close to each other and the ring 24 is fitted into the ram duct 21. The ram duct unit 1 can be assembled by fitting in this way. Further, the front end portion of the sound absorbing sponge 23 can be pressed against the inner peripheral portion of the main body 21a by the ring 24, and the front end portion of the sound absorbing sponge 23 can be prevented from rolling up. Further, since the inner holes 41a of the pair of projecting portions 41 extend in the left-right direction similarly to the fitting groove portion 42, the pin portion 33 is fitted into the inner hole 41a by fitting the ring 24 into the respective portions 51 and 52. Inserted.

  As described above, since the ram duct 21 has a left and right divided structure, the ring 24 is interposed between the portions 51 and 52, and the operation of fitting the ring 24 into the portions 51 and 52 and the pin portion are performed. The operation of inserting 33 into the corresponding protrusion 41 can be performed simultaneously. Therefore, the assembly of the ram duct unit 1 is easy. Further, by making the ram duct 21 into a left and right divided structure, it is possible to easily assemble the ring 24 formed in a downwardly tapered trapezoidal shape into the ram duct 21.

  In the ram duct unit 1 configured as described above, the front end portion of the sound absorbing sponge 23 is pressed against the inner surface portion of the ram duct 21 by the ring 24, so that the ring 24 is introduced into the ram duct 21 even if the ring 24 is configured by a linear member. It is possible to prevent the sound absorbing member from being beaten and peeled off by the air that is generated. The ram duct 21 is formed in a three-dimensional shape in which unevenness and curves are three-dimensionally combined. However, since the ring 24 is composed of a linear member, the shape of the ring 24 can be simplified. Therefore, the yield of the ram duct 21 can be improved while suppressing the peeling of the sound absorbing sponge 23.

  Further, in the ram duct unit 1 of the present embodiment, since the ring 24 is formed in an annular shape, the manufacturing of the ring 24 is easy, and the ring 24 is deformed as compared with the case where the ring 24 is formed in a U shape. Can be suppressed.

  Furthermore, in the ram duct unit 1 of the present embodiment, the resonator chamber 27 is formed on the opposite side of the intake passage 25 via the isolation wall 26, that is, on the lower side of the isolation wall 26. The transmitted intake noise can be attenuated in the resonator chamber 27. Accordingly, the transmission of intake noise can be suppressed by the resonator chamber 27 without attaching the sound absorbing sponge 23 to the isolation wall 26. That is, noise in the ram duct unit 1 can be reduced without attaching the sound absorbing sponge 23 to the isolation wall 26.

  Further, by removing the part of the isolation wall 26 from the region where the sound absorbing sponge 23 is applied, it is necessary to form a recess for placing the sound absorbing sponge 23 compared to the case where the sound absorbing sponge 23 is applied to the isolation wall 26. Therefore, the isolation wall 26 can be moved toward the intake passage 25. That is, the isolation wall 26 can be prevented from falling to the resonator chamber 27 side, and the volume of the resonator chamber 27 can be increased. Thereby, the freedom degree of selection of the frequency band of the intake noise to attenuate can be expanded.

  In addition, since the sound absorbing sponge 23 is pressed by the ring 24 formed of a linear member, it is possible to prevent the surface of the sound absorbing sponge 23 from being uneven as in the prior art holder. Thereby, the intake resistance and intake noise of the ram duct 21 can be reduced.

[Other embodiments]
In the ram duct unit 1 of the above-described embodiment, the ram duct 21 is configured to be divided into left and right, but may be configured such that the ram duct 21 is divided up and down. In the ram duct unit 1 of the above-described embodiment, the resonator chamber 27 is formed. However, the resonator chamber 27 is not always necessary and may be omitted. Moreover, although the cross section of the main body 21a of the ram duct 21 has a substantially trapezoidal shape, it is not limited to the shape, and may be a quadrangle or a triangle, or may be a pentagon or more polygonal shape. Moreover, the cross section of the main body 21a of the ram duct 21 may be a shape combining curves.

  In the ram duct unit 1 of the above-described embodiment, the sound absorbing sponge 23 is attached to the region excluding the part of the isolation wall 26 in the middle portion in the front-rear direction of the inner surface of the main body 21a. May extend to the part of the isolation wall 26. That is, the sound absorbing sponge 23 may be provided over the entire circumference of the inner surface of the main body 21a in the middle portion in the front-rear direction.

  In the ram duct unit 1 of the above-described embodiment, the ring 24 is made of synthetic resin, but may be a metal material. The shape of the ring 24 is not limited to an annular shape, and may be U-shaped in accordance with the shape of the sound absorbing sponge 23. The ring 24 is formed of a linear member and substantially extends on one plane. Any shape can be used. Further, the protruding piece 32 may be provided not only on the left side portion 31b and the right side portion 31d of the ring 24 but also on the upper side portion 31a, and when the sound absorbing sponge 23 is extended also on the isolation wall 26, the lower side The protruding piece 32 may also be provided on the portion 31c. Furthermore, in the ram duct unit 1, the ring 24 is disposed only at the front end portion of the sound absorbing sponge 23, but it may be disposed at the rear end portion or the intermediate portion of the sound absorbing sponge 23 in addition to the front end portion of the sound absorbing sponge 23. The number of rings 24 arranged is not limited.

DESCRIPTION OF SYMBOLS 1 Ram duct unit 2 Motorcycle 21 Ram duct 21d Open end 23 Sound absorption sponge 23c Through-hole 24 Ring 25 Intake passage 26 Isolation wall 27 Resonator chamber 29 Mounting groove part 33 Pin part 41 Protrusion part 42 Fitting groove part E Engine

Claims (9)

A ram duct forming an intake passage for guiding air to the engine;
A sound-absorbing member attached along the inner surface defining the intake passage of the ram duct;
A pressing member pressing the upstream end of the sound absorbing member against the inner surface of the ram duct;
The ram duct unit, wherein the pressing member is formed of a linear member extending on a plane perpendicular to the air flow direction so that the dimension in the flow direction is shortened.   The said pressing member is cyclically | annularly formed according to the shape of the inner surface part of the said ram duct, and is pressing the inner surface part of the upstream edge part in the said sound absorption member against the inner surface part of the said ram duct over the whole circumferential direction. Ram duct unit as described in. A plurality of locking portions are formed on the inner surface of the ram duct at intervals in the circumferential direction,
The ram duct unit according to claim 1 or 2, wherein the pressing member is positioned by being fitted to the locking portion.   The ram duct unit according to claim 3, wherein at least three locking portions are formed on an inner surface portion of the ram duct. The inner surface portion of the ram duct has a linear inner surface portion extending in a vertical direction perpendicular to the flow direction,
In the linear inner surface portion, a fitting groove portion that is one of the plurality of locking portions is formed,
The ram duct unit according to claim 3 or 4, wherein the fitting groove portion is formed in a long shape extending along the vertical direction. The plurality of locking portions are formed on an inner surface portion of the ram duct, and include a protruding portion that protrudes from the inner surface portion of the ram duct to the inside of the ram duct,
The ram duct unit according to any one of claims 3 to 5, wherein the sound absorbing member is formed with a through hole through which the protruding portion is inserted. On the upstream side of the ram duct, an air inlet portion for taking in air is formed,
The inner surface of the ram duct is formed with a recess for arranging the sound absorbing member,
The recess portion is formed such that an inner surface of the sound absorbing member is flush with an inner surface of the intake port portion or is positioned closer to an inner surface portion of the ram duct than an inner surface of the intake port portion. The ram duct unit according to any one of the above. The ram duct is formed with a resonance chamber that communicates with the intake passage, and has an isolation wall that separates the intake passage and the resonance chamber.
The isolation wall constitutes a part of the inner surface of the ram duct;
The ram duct unit according to any one of claims 1 to 7, wherein the sound absorbing member is attached to a region of the inner surface portion of the ram duct excluding the isolation wall.   A motorcycle comprising the ram duct unit according to any one of claims 1 to 8.