JP6990364B2 - Intake duct - Google Patents

Description

The present disclosure relates to an intake duct that partitions an intake flow path to the engine side.

Patent Document 1 discloses an intake duct of a cab-over type vehicle. This intake duct has a snorkel as an intake duct fixed to the rear wall of the cab, a rubber bellows-shaped upper elastic cylinder integrally connected to the lower part of the snorkel, and a cap with a downward opening of the upper elastic cylinder. Equipped with a lower duct to wear. The snorkel is a resin molded product and has a flat bulging container shape. The lower duct is a resin molded product, has a flat rectangular container shape, has an inflow opening formed above it, and has a lateral cylinder extending over the forward wall. The side cylinder is connected to the engine side via an air cleaner or the like. Three inward protrusions are formed on the forward wall of the lower duct, and the tip of each protrusion is integrally connected to the inner wall surface of the rear wall. A bolt head is embedded in the joint portion between each protrusion and the rear facing wall, and a fixing bracket is fixed to the threaded portion of each bolt protruding to the outside. The fixing bracket is integrally connected to the horizontal base frame for supporting the duct. The horizontal base frame fixes the lower duct and the air cleaner, and these are attached to the side rails via the vertical base frame.

Japanese Unexamined Patent Publication No. 9-144615

Like the intake duct described in Patent Document 1, the resin intake duct is formed in a flat tubular shape and has an opening on one side in the minor axis direction, and the opening is connected to the engine side. Occasionally, when a negative pressure is generated inside the duct, the wall portion on the other side facing the opening on one side may be dented toward the inside of the duct, which may narrow the cross-sectional area of the intake air passage.

In the intake duct described in Patent Document 1, three inward protrusions are formed on the forward wall of the lower duct, and the tip of each protrusion is integrally connected to the inner wall surface of the rear wall, and each protrusion and the rear wall are combined. Since the fixing bracket is fixed to the bolt embedded in the joint part of the wall, it is possible to suppress the dent in the front of the rear facing wall. However, in the intake duct described in Patent Document 1, since it is necessary to form an inward protrusion or embed a bolt, the structure of the intake duct is complicated, and the molding of the intake duct may be complicated. There is.

Therefore, an object of the present disclosure is to provide an intake duct capable of preventing a dent on the inner side with a simple structure.

In order to solve the above problems, the first aspect of the present invention has at least a region formed in a flat tubular shape in which a pair of facing wall portions along the major axis direction are separated from each other in the minor axis direction and face each other. , An intake duct that partitions the flow path of intake air to the engine side, and includes an opening and a protruding curved surface region. The opening is provided on the facing wall side of one of the pair of facing walls and is connected to the engine side. The protruding curved surface region is provided on the opposite wall portion side of the other facing wall portion of the pair of facing wall portions, faces at least a part of the opening portion, and projects outward in a spherical shape.

In the above configuration, an opening connected to the engine side is provided on the facing wall side of one of the pair of facing wall portions along the major axis direction of the intake duct, and the opening is provided on the other facing wall portion side. A protruding curved surface region facing at least a part thereof is provided. Therefore, when a negative pressure is generated inside the intake duct during intake, a force acts on the protruding curved surface region of the other facing wall portion toward the opening side. Since the protruding curved surface region of the other facing wall portion protrudes to the outside in a spherical shape, the region facing the opening of the other facing wall portion is flat as compared with the case where the facing wall portion is flat. It is possible to suppress the dent deformation (deformation dented toward the opening side) of the other facing wall portion toward the opening side when a force applied to the opening side is applied.

Further, it has a simple structure in which an opening is provided on one facing wall side and a protruding curved surface region is provided on the other facing wall side (a position facing at least a part of the opening in the other facing wall portion). Therefore, the intake duct can be easily formed.

Further , since the protruding curved surface region on the other facing wall side projects spherically to the outside side, the cross-sectional shape of the protruding curved surface region along the minor axis direction becomes curved at any position of the protruding curved surface region. .. Therefore, it is possible to suitably suppress the dent deformation of the other facing wall portion toward the opening side when a force acting on the other facing wall portion is applied to the opening side.

The second aspect of the present invention is the intake duct of the first aspect, which includes ribs. The rib is provided in at least the protruding curved surface region of the other facing wall portion, and extends in a direction that intersects the minor axis direction in a state of being recessed inward.

In the above configuration, since the other facing wall portion is provided with a rib that is arranged at least in the protruding curved surface region and extends in a direction that intersects the minor axis direction in a state of being recessed inward, the other is provided with respect to a force in the minor axis direction. The rigidity of the facing wall portion is increased, and it is possible to suitably suppress the dent deformation of the other facing wall portion toward the opening side when a force applied to the other facing wall portion is applied to the opening side.

According to the present disclosure, it is possible to prevent a dent on the inner side of the intake duct with a simple structure.

It is a schematic side view of the vehicle equipped with the intake duct which concerns on one Embodiment of this invention, (a) shows the non-tilt state, (b) shows the tilt state respectively. It is a schematic perspective view from the rear of the vehicle equipped with the intake duct which concerns on one Embodiment of this invention. It is a perspective view of the lower intake duct. It is a partial cross-sectional view seen from the side of the lower intake duct. It is a bottom view of the lower intake duct. It is a rear view of the lower intake duct. It is explanatory drawing about the molding of the lower intake duct.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In each figure, FR indicates the front of the vehicle, UP indicates the upper side, and IN indicates the inside in the vehicle width direction. Further, in the following description, the left-right direction means the left-right direction in a state of facing the front of the vehicle.

As shown in FIGS. 1A and 1B, the vehicle 1 provided with the intake duct 10 according to the present embodiment is, for example, a cab-over type vehicle 1 in which the cab 2 is generally arranged above the engine 3. be. The cab 2 is cab 2 from a non-tilted state (a state shown in FIG. 1A) in which the lower part of the front end thereof is rotatably supported by the vehicle body frame 4 and the rear end side of the cab 2 is supported by the vehicle body frame 4. The rear end can be tilted forward and upward to bring it into a tilted state (the state shown in FIG. 1B). The intake duct 10 partitions the flow path of the intake air to the engine 3 side. The intake air is guided to the air cleaner 5 by the intake duct 10, and is supplied to the engine 3 side via the air cleaner 5.

As shown in FIGS. 1 (a), 1 (b) and 2, the intake duct 10 extends in the vertical direction behind the cab 2, the lower end side is connected to the engine 3 side, and the intake port 10a on the upper end side. Guide the sucked intake air (air) to the engine 3 side. The intake duct 10 is supported by the upper intake duct 11 extending along the back surface 2a of the cab 2 and fixed to the back surface 2a, the bellows duct 12 fixed to the upper intake duct 11, and the vehicle body frame 4. It has a lower intake duct 13. The intake duct 10 is arranged at the outer end portion of the back surface 2a of the cab 2 on one side in the vehicle width direction (on the right side in this embodiment). The bellows duct 12 and the lower intake duct 13 are vertically and vertically separably connected to each other. When the cab 2 is changed from the non-tilted state to the tilted state, the upper intake duct 11 and the bellows duct 12 separate from the lower intake duct 13 and tilt forward and upward together with the cab 2, and the lower intake duct 13 tilts. It is supported on the 4th side of the vehicle body frame. In the present embodiment, the intake duct 10 is arranged at the outer end portion in the vehicle width direction on the right side of the back surface 2a of the cab 2, but the present invention is not limited to this, and the intake duct 10 is placed on the back surface 2a of the cab 2. It may be arranged at the outer end portion in the vehicle width direction on the left side, or may be arranged at the center portion in the vehicle width direction of the back surface 2a of the cab 2.

The upper intake duct 11 is a resin duct formed in a flat tubular shape whose length in the front-rear direction is shorter than the length in the vehicle width direction in order to suppress the amount of protrusion from the back surface 2a of the cab 2 to the rear. It extends in the vertical direction and partitions the intake flow path (not shown) inside. At the upper end of the upper intake duct 11, an intake port 10a that communicates the inside and the outside of the upper intake duct 11 is provided. A cover member 14 is attached to the intake port 10a. A plurality of openings are formed in the cover member 14, and while covering the intake port 10a, the intrusion of rainwater or the like from the outside to the inside of the upper intake duct 11 is suppressed, and the intrusion of rainwater or the like from the outside to the inside of the upper intake duct 11 is suppressed. Allows the inflow of air. The lower end of the upper intake duct 11 is arranged in the vicinity of the lower end of the back surface 2a of the cab 2.

The bellows duct 12 is a resin duct formed in a flat tubular shape whose length in the front-rear direction is shorter than the length in the vehicle width direction in order to suppress the amount of protrusion from the back surface 2a of the cab 2 to the rear. It extends in the direction, and the upper end side is fixed to the lower end of the upper intake duct 11. The bellows duct 12 is formed in a bellows shape to partition an air supply flow path (not shown) inside. The lower end opening (not shown) of the bellows duct 12 allows the upper end portion of the lower intake duct 13 to be described later to enter, and is connected to the upper end portion of the lower intake duct 13 in the non-tilted state. The bellows duct 12 connects the upper intake duct 11 and the lower intake duct 13 in a non-tilted state, and allows relative displacement between the upper intake duct 11 and the lower intake duct 13 due to vibration or the like to allow vibration. Absorb.

As shown in FIGS. 3 to 6, the lower intake duct 13 is a resin duct integrally molded with substantially the same plate thickness by blow molding, and is formed in an elbow shape bent at a substantially right angle, and is formed above. The intake air from the upper intake duct 11 side is guided to the front air cleaner 5. The lower intake duct 13 has a flat tubular insertion connecting portion 13a inserted into the bellows duct 12 and a flat tubular lower duct main body (in a flat tubular shape) extending downward continuously from the lower end of the insertion connecting portion 13a. The formed region) 13b and the tubular connecting portion 13c extending forward from the lower end portion of the lower duct main body 13b and connected to the air cleaner 5 (see FIG. 1A) are integrally provided. The insertion connecting portion 13a and the lower duct main body 13b are formed in a flat tubular shape whose length in the front-rear direction is shorter than the length in the vehicle width direction in order to suppress the amount of protrusion from the back surface 2a of the cab 2 to the rear. The bending angle of the lower intake duct 13 is not limited to a substantially right angle.

The insertion connecting portion 13a of the lower intake duct 13 has a long hole-shaped upper end opening 18 in the vehicle width direction. A guide member 19 is attached to the insertion connecting portion 13a. The guide member 19 has a flat tubular fixing portion 19a fixed to the insertion connecting portion 13a of the lower intake duct 13, and a guide portion 19b protruding upward from the fixing portion 19a. The fixing portion 19a is fixed to the insertion connecting portion 13a of the lower intake duct 13 in a state of being arranged on the outer periphery of the insertion connecting portion 13a of the lower intake duct 13. The guide portion 19b has a shape that protrudes upward in a side view, and is formed by a plurality of rods to allow air flow in the vertical direction. The guide portion 19b prevents the lower end opening of the bellows duct 12, which tilts downward together with the cab 2, and the insertion connecting portion 13a of the lower intake duct 13 from being displaced when the cab 2 is changed from the tilted state to the non-tilted state. In the lower end opening of the bellows duct 12, the insertion connecting portion 13a of the lower intake duct 13 is guided.

The lower duct main body 13b of the lower intake duct 13 is formed in a flat tubular shape in which the length L1 in the front-rear direction (minor axis direction) is shorter than the length L2 in the vehicle width direction (major axis direction), and the bellows duct 12 and the lower side. It is exposed below the bellows duct 12 in a state where it is connected to the side intake duct 13. The lower duct main body 13b has front and rear facing wall portions (a pair of facing wall portions) 15 and 16 that are separated from each other in the front-rear direction and face each other, and left and right facing wall portions 20 that are separated from each other in the vehicle width direction and face each other. 21 and a bottom wall portion 22 arranged at a position facing the upper end opening 18 of the insertion connecting portion 13a, and guide the intake air from above downward. The front and rear facing wall portions 15 and 16 partition the front and rear of the intake flow path 17 (the flow path behind the two-dot chain line 6 in FIG. 4) extending in the vertical direction, and the left and right facing wall portions 20 and 21. Partitions the left and right sides of the intake flow path 17, and the bottom wall portion 22 partitions below the intake flow path 17. The two-dot chain line 6 in FIG. 4 is a virtual extension line in which the front facing wall portion 15 is linearly extended downward.

The facing wall portion (one facing wall portion) 15 on the front side is formed in a substantially flat plate shape, and extends long in the vehicle width direction in a state of being crossed with the front-rear direction below the insertion connecting portion 13a. Below the facing wall portion 15 on the front side (position indicated by the alternate long and short dash line 6 in FIG. 4), the intake flow path 17 inside the lower duct main body 13b in the lower intake duct 13 and the lower intake duct 13 A front opening (opening) 23 that communicates with the intake flow path 24, which will be described later, of the connecting portion 13c of the above is provided. That is, a front opening 23 connected to the engine 3 side is provided on the front facing wall portion 15 side of the front and rear facing wall portions 15 and 16. The front opening 23 is formed in a substantially rectangular shape having a length in the vehicle width direction longer than a length in the vertical direction. The upper end of the front opening 23 is partitioned by the lower end edge of the facing wall portion 15 on the front side, and the lower end of the front opening 23 is partitioned by the front end edge of the bottom wall portion 22 of the lower duct body 13b. The left and right ends are partitioned by the front end edges of the left and right facing wall portions 20 and 21 of the lower duct main body 13b.

The rear facing wall portion (the other facing wall portion) 16 is formed in a substantially rectangular shape in the rear view, and extends in the vehicle width direction and the vertical direction while intersecting the front-rear direction. The facing wall portion 16 on the rear side includes a protruding curved surface region 25 that protrudes rearward in a spherical shape at a substantially central portion of the facing wall portion 16 on the rear side, and a planar flat region 27 that surrounds the periphery of the protruding curved surface region 25. Is provided. The protruding curved surface region 25 is a rear view circular region centered on the upper, lower, left and right substantially centers of the facing wall portion 16 on the rear side, and faces a part of the front opening portion 23 of the facing wall portion 15 on the front side. .. The projecting curved surface region 25 projecting rearward in a spherical shape has any cross-sectional shape (cross-sectional shape along the minor axis direction (front-rear direction)) viewed from the direction intersecting the front-rear direction (vertical direction or vehicle width direction). Even at the position, it becomes a curved surface with a substantially arc shape. The central portion of the protruding curved surface region 25 in the rear view is the portion most protruding rearward, and is the rear end of the facing wall portion 16 on the rear side. The upper end 25a of the protruding curved surface region 25 is arranged above the upper end 23a of the front opening 23 of the facing wall portion 15 on the front side. The lower end 25b of the protruding curved surface region 25 is arranged slightly above the lower end 23b of the front opening 23. The vehicle width direction inner end 25c of the protruding curved surface region 25 is arranged outside the vehicle width direction from the vehicle width direction inner end 23c of the front opening 23 and below the upper end 23a of the front opening 23, and the protruding curved surface region 25 The outer end 25d in the vehicle width direction is arranged inside the outer end 23d in the vehicle width direction of the front opening 23 and below the upper end 23a of the front opening 23. The facing wall portion 16 on the rear side is provided with a plurality of ribs 27a to 27d (four in the present embodiment) extending in the vertical direction in a state of being recessed forward. The protruding curved surface region 25 having a circular shape in the rear view includes not only a completely circular protruding curved surface region 25 in the rear view but also an elliptical protruding curved surface region 25 in the rear view. Further, the spherical protruding curved surface region 25 has a substantially arcuate curved surface shape at any position in terms of the cross-sectional shape (cross-sectional shape along the minor axis direction) viewed from the direction intersecting the minor axis direction (front-back direction). It may be in the area of. That is, the spherical protruding curved surface region 25 includes not only the protruding curved surface region 25 of a perfect spherical surface protruding toward the outside (in the present embodiment, the rear), but also the protruding curved surface region 25 in a state close to a spherical surface. Further, in FIGS. 3 and 6, the boundary line between the plane area 27 and the protruding curved surface area 25 is shown for the sake of clarity, but the boundary line between the plane area 27 and the protruding curved surface area 25 recognizes the boundary line. It may be as clear as possible, or it may be a gentle curved surface where the boundary line cannot be recognized.

The ribs 27a to 27d are arranged apart from each other in the vehicle width direction and substantially parallel to each other, and extend linearly in the vertical direction in a state of being recessed forward. The upper end and the lower end of the ribs 27a to 27d are arranged in the plane region 27 of the facing wall portion 16 on the rear side, and the intermediate portion of the ribs 27a to 27d is arranged in the protruding curved surface region 25 of the facing wall portion 16 on the rear side. Will be done. That is, the region where the ribs 27a to 27d are arranged in the plane region 27 of the facing wall portion 16 on the rear side is recessed forward. Further, in the protruding curved surface region 25 of the facing wall portion 16 on the rear side, the region where the ribs 27a to 27d are arranged is recessed forward. The depth of the ribs 27a to 27d (the length from the bottom surface portion 28 of the ribs 27a to 27d to the rear surface of the facing wall portion 16 on the rear side) is deepest in the central portion in the vertical direction of the protruding curved surface region 25.

The facing wall portion 20 on the left side of the lower duct main body 13b connects the inner end edges of the front and rear facing wall portions 15 and 16 in the vehicle width direction. The facing wall portion 21 on the right side of the lower duct main body 13b connects the outer end edges of the front and rear facing wall portions 15 and 16 in the vehicle width direction. The bottom wall portion 22 of the lower duct main body 13b continuously curves downward and gently extends downward from the lower end edge of the facing wall portion 16 on the rear side, and the upper surface of the front end edge thereof is the lower end of the front opening 23. Partition 23b.

The connecting portion 13c of the lower intake duct 13 is formed in a cylindrical shape that partitions the air supply flow path 24 extending forward from the front opening 23. The front end portion 26 of the connecting portion 13c is provided with a circular front end opening 29 connected to the air cleaner 5. That is, the connecting portion 13c has a circular shape toward the front from the front opening 23, and communicates the substantially rectangular front opening 23 with the circular front end opening 29. The diameter (length in the height direction) L3 of the front end portion 26 of the connecting portion 13c is longer than the length L1 in the front-rear direction of the lower duct main body 13b and shorter than the length L2 in the vehicle width direction of the lower duct main body 13b. .. Further, the diameter L3 of the front end portion 26 of the connecting portion 13c is shorter than the vertical length of the protruding curved surface region 25 of the facing wall portion 16 on the rear side, and shorter than the vertical length of the front opening portion 23. The front end opening 29 of the connecting portion 13c is arranged in the front opening portion 23 in the rear view, and a part of the front end opening 29 faces the protruding curved surface region 25 of the facing wall portion 16 on the rear side. The upper end 29a of the front end opening 29 of the connecting portion 13c is below the upper end 25a of the protruding curved surface region 25 and the upper end 23a of the front opening 23, and above the height position of the central portion in the vertical direction of the protruding curved surface region 25. Be placed. The lower end 29b of the front end opening 29 of the connecting portion 13c is arranged at substantially the same height as the lower end 23b of the front opening 23, that is, the lower end 29b of the front end opening 29 of the connecting portion 13c is the lower end of the protruding curved surface region 25. It is placed slightly below 25b. The vehicle width direction inner end 29c of the front end opening 29 of the connecting portion 13c is arranged outside the vehicle width direction inner end 25c of the protruding curved surface region 25. The vehicle width direction outer end 29d of the front end opening 29 of the connecting portion 13c is arranged inside the vehicle width direction outer end 25d of the protruding curved surface region 25.

A drainage portion 31 projecting downward is formed at the central portion of the lower surface portion 30 of the connecting portion 13c in the vehicle width direction. A drainage port (not shown) is formed at the bottom of the drainage section 31, and water droplets that have entered or are generated in the intake duct 10 are discharged from the drainage port of the drainage section 31. The angle of the front wall portion 31a of the drainage portion 31 with respect to the lower surface portion 30 in front of the drainage portion 31 (the angle in front of the front wall portion 31a) is the rear wall of the drainage portion 31 with respect to the lower surface portion 30 behind the drainage portion 31. It is larger than the angle of the portion 31b (the angle behind the rear wall portion 31b). As shown in FIG. 7, when the lower intake duct 13 is blow-molded using the mold 32, the lower duct 13 is above the mold 32 with the corners of the lower duct main body 13b and the connecting portion 13c facing downward. Will be removed. The front wall portion 31a of the drainage portion 31 extends linearly along the removal direction (along the vertical direction in FIG. 7) when the blow-molded lower intake duct 13 is removed from the mold 32.

In the lower duct main body 13b of the lower intake duct 13 configured as described above, the length L1 in the front-rear direction (minor axis direction) is the length of the lower duct main body 13b in the vehicle width direction (major axis direction). It is formed in a flat tubular shape shorter than the L2, and the front opening 23 is provided in the facing wall portion 15 on the front side of the lower duct main body 13b. Therefore, when a negative pressure is generated inside the lower intake duct 13 of the intake duct 10 at the time of intake, a force acts on the facing wall portion 16 on the rear side toward the front opening portion 23 on the front side. The rear facing wall portion 16 is provided with a protruding curved surface region 25 facing a part of the front opening 23 of the front facing wall portion 15, and the protruding curved surface region 25 projects rearward in a spherical shape. Compared to the case where the rear facing wall portion 16 is formed in a planar shape without providing the protruding curved surface region 25 on the side facing wall portion 16, when a forward force acts on the rear facing wall portion 16 It is possible to suppress the dent deformation of the facing wall portion 16 on the rear side (the dent deformation toward the front opening 23 side).

Further, a front opening 23 is provided in the facing wall portion 15 on the front side of the lower duct main body 13b formed in a flat tubular shape, and is located at a position facing at least a part of the front opening 23 in the facing wall portion 16 on the rear side. Since the structure is simple in that the protruding curved surface region 25 is provided, the lower intake duct 13 of the intake duct 10 can be easily formed.

Further, the protruding curved surface region 25 of the facing wall portion 16 on the rear side protrudes in a spherical shape, and the cross-sectional shape of the protruding curved surface region 25 viewed from the direction crossing the front-rear direction (vertical direction or vehicle width direction) is a substantially arcuate curved surface. It becomes a shape. That is, since the cross-sectional shape of the protruding curved surface region 25 along the front-rear direction is curved at any position of the protruding curved surface region 25, the rear side when a forward force is applied to the facing wall portion 16 on the rear side. It is possible to suitably suppress the dent deformation of the facing wall portion 16.

Further, since the ribs 27a to 27d extending in the vertical direction are provided on the facing wall portion 16 on the rear side in a state of being recessed forward, the rigidity of the facing wall portion 16 on the rear side with respect to the force in the front-rear direction is increased. .. Therefore, it is possible to suitably suppress the dent deformation of the rear facing wall portion 16 when a forward force is applied to the rear facing wall portion 16.

Therefore, according to the present embodiment, the lower intake duct 13 of the intake duct 10 can be easily formed, and the inward dent on the front side of the facing wall portion 16 on the rear side of the lower intake duct 13 is formed. Can be prevented.

Further, the front wall portion 31a of the drainage portion 31 of the lower intake duct 13 is straight along the removal direction (in the vertical direction in FIG. 7) when the blow-molded lower intake duct 13 is removed from the mold 32. Since it extends in a shape, it is possible to prevent interference between the front wall portion 31a of the drainage portion 31 and the mold 32 when the blow-molded lower intake duct 13 is removed upward from the mold 32, and the lower intake duct 13 can be prevented from interfering with the mold 32. 13 can be removed upward from the mold 32. Therefore, unlike the case where the front wall portion 31a of the drainage portion 31 and the mold 32 interfere with each other, the position of the mold 32 corresponding to the front wall portion 31a of the drainage portion 31 is higher than that of the lower intake duct 13. Since it is not necessary to provide the slide mold portion that can be removed from the mold 32 in advance, the mold 32 can have a simple structure by that amount, and the manufacturing cost of the mold 32 can be suppressed.

Further, since the ribs 27a to 27d recessed forward are provided on the facing wall portion 16 on the rear side, the amount of protrusion of the intake duct 10 to the rear can be suppressed unlike the case where the ribs 27a to 27d are projected to the rear.

In the present embodiment, the intake duct 10 is composed of an upper intake duct 11, a bellows duct 12, and a lower intake duct 13, and when the cab 2 is tilted, the bellows duct 12 and the lower intake duct 13 are used. Is a duct that can be separated from each other up and down, but the intake duct 10 is not limited to this. For example, the intake duct 10 may be configured such that the bellows duct 12 and the lower intake duct 13 are not vertically separated from each other, and the intake duct 10 may be applied to a vehicle that does not tilt.

Further, in the present embodiment, the intake duct 10 is configured to be long in the vertical direction (predetermined direction) by the upper intake duct 11, the bellows duct 12, and the lower intake duct 13, but the shape of the intake duct is limited to this. For example, it may be a short intake duct in the vertical direction such as the lower intake duct 13.

Further, in the present embodiment, the lower intake duct 13 of the intake duct 10 is a bent elbow type duct, but the shape of the lower intake duct 13 is not limited to this, and for example, the lower duct main body. The 13b is formed in the shape of a bottomed rectangular tubular box that opens upward, and a circular opening (opening) is formed at a predetermined position (central portion, etc.) of the facing wall portion 15 on the front side of the lower duct main body 13b. A duct having a connection portion 13c extending from the opening to the engine 3 side may be used. That is, in the opening provided in the facing wall portion 15 on the front side, a part of the outer edge of the opening is formed by the bottom wall portion 22 and the front end edges of the left and right facing wall portions 20, 21 as in the present embodiment. It may be the front opening 23 to be partitioned, or the entire outer edge of the opening may be an opening partitioned by the facing facing wall 15 on the front side (a predetermined position (central portion) of the facing wall portion 15 on the front side). Etc.) may be an opening).

Further, in the present embodiment, an intake duct 10 composed of an upper intake duct 11 and a bellows duct 12 extending in the vertical direction and an elbow-shaped lower intake duct 13 bent forward at the lower end of the intake duct 10 is exemplified. However, the intake duct is not limited to this. The intake duct may be an intake duct having a flat cylindrical region in which a pair of facing wall portions along the major axis direction are separated from each other in the minor axis direction and face each other. That is, the minor axis direction of the intake duct is not limited to the front-rear direction, the major axis direction of the intake duct is not limited to the vehicle width direction, and the extending direction of the intake duct is not limited to the vertical direction. Further, the arrangement position of the intake duct is not limited to the rear of the cab 2.

Further, in the present embodiment, the shape of the front opening 23 is a substantially rectangular shape in which the length in the vehicle width direction is longer than the length in the vertical direction, but the shape of the front opening 23 is not limited to this. Various shapes can be applied.

Further, in the present embodiment, the protruding curved surface region 25 projecting rearward in a spherical shape is provided on the facing wall portion 16 on the rear side, but the shape of the protruding curved surface region 25 is not limited to the spherical shape. For example, the shape of the protruding curved surface region 25 may be a shape extending linearly in a direction intersecting the minor axis direction (vertical direction, vehicle width direction, etc.) in a state of protruding outward in an arc shape (curved surface shape).

Further, in the present embodiment, four ribs 27a to 27d are provided on the facing wall portion 16 on the rear side, but the number of ribs is not limited to this. The facing wall portion 16 on the rear side may be provided with one or a plurality of ribs. Alternatively, it is not necessary to provide the rib on the facing wall portion 16 on the rear side.

Further, in the present embodiment, a plurality of ribs 27a to 27d extending in the vertical direction are provided on the facing wall portion 16 on the rear side, but the direction in which the ribs 27a to 27d are extended is not limited to this, and the front and rear ribs 27a to 27d are provided. It may be a direction that intersects with the direction (minor diameter direction). For example, a rib extending along the vehicle width direction may be provided on the facing wall portion 16 on the rear side.

Further, in the present embodiment, the lower intake duct 13 is integrally molded by blow molding, but the present invention is not limited to this, and for example, the lower duct main body 13b and the connecting portion 13c are separately molded and then fixed to each other. You may.

Further, in the present embodiment, the intake duct 10 of the vehicle 1 has been described, but the intake duct may be applied to other than the vehicle 1.

Although the present invention has been described above based on the above-described embodiment, the present invention is not limited to the contents of the above-described embodiment, and can be appropriately modified without departing from the present invention. That is, it goes without saying that all other embodiments, examples, operational techniques, and the like made by those skilled in the art based on this embodiment are included in the scope of the present invention.

3: Engine 10: Intake duct 13: Lower intake duct 15: Front facing wall portion (one facing wall portion of a pair of facing wall portions)
16: Rear facing wall portion (the other facing wall portion of the pair of facing wall portions)
17: Intake flow path 23: Front opening (opening)
25: Protruding curved surface area 27a to 27d: Rib

Claims (2)

It is an intake duct that has at least a flat cylindrical region in which a pair of facing walls along the major axis are separated from each other in the minor axis direction and face each other, and partitions an intake flow path to the engine side.
An opening provided on the facing wall side of one of the pair of facing wall portions and connected to the engine side, and an opening.
It is provided with a protruding curved surface region provided on the other facing wall side of the pair of facing wall portions, facing at least a part of the opening and projecting spherically to the outside side. Intake duct featuring. The intake duct according to claim 1.
A rib provided in at least the protruding curved surface region of the other facing wall portion and extending in a direction that intersects with the minor axis direction in a state of being recessed inward is provided.
The intake duct is characterized by that.

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