WO2020095409A1

WO2020095409A1 - Air cleaner

Info

Publication number: WO2020095409A1
Application number: PCT/JP2018/041494
Authority: WO
Inventors: 哲範岩本; 裕幸新村; 孝彦清水
Original assignee: 本田技研工業株式会社
Priority date: 2018-11-08
Filing date: 2018-11-08
Publication date: 2020-05-14
Also published as: JPWO2020095409A1; CN215256523U; BR112021007407A2; MY196537A; JP7049481B2

Abstract

An air cleaner (39) is provided with: a cleaner case (45) in which are formed a pre-purification chamber (52a) connecting to the outside air and a purification chamber (52b) connecting to a combustion chamber of an engine (29) to which purified air is supplied; a cleaner element (49) that is arranged between the pre-purification chamber (52a) and the purification chamber (52b) and that purifies outside air; and an air intake duct (54) that is secured to the cleaner case (45) and that has an upstream end (54a) which opens into a space outside the cleaner case (45) and a downstream end (54b) which faces the pre-purification chamber (52a), wherein a peripherally extending wall body (65) that maintains a gap (S2) with the outer peripheral surface of the air intake duct (54) is arranged at the downstream end (54b) of the air intake duct (54). Negative pressure waves flow smoothly into the downstream end (54b) of the air intake duct (54) without flowing backwards in a vortex along the inner periphery of the downstream end (54b).

Description

air cleaner

The present invention includes a cleaner case that forms an unpurified chamber that communicates with the outside air, and a purification chamber that communicates with a combustion chamber of an engine that is a supply destination of purified air, and is disposed in the cleaner case between the unpurified chamber and the purified chamber. The present invention relates to an air cleaner that includes a cleaner element, and an intake duct that is fixed to the cleaner case and has an upstream end that opens to a space outside the cleaner case and a downstream end that faces the unpurified chamber.

Patent Document 1 discloses an intake duct that guides air to a carburetor in a motorcycle. The intake duct has a tubular portion connected to the carburetor, a chamber portion provided on the intake upstream side of the tubular portion and having an inner diameter larger than that of the tubular portion, and protruding into the internal space of the chamber portion continuously from the tubular portion, And an extended inner wall portion forming an extended flow passage communicating with the flow passage of the tubular portion. By extending the flow path of the tubular part, the turbulent flow of the airflow introduced from the tubular part is suppressed, and the airflow is rectified.

Japanese Patent Laid-Open No. 2011-43165

Pulsation effect is used in engine intake. When the intake valve opens, a negative pressure wave is generated and propagates at a sonic velocity from the downstream end of the intake duct to the upstream end of the intake duct through the purified chamber and the unpurified chamber. The pressure wave reverses at the upstream end of the intake duct to become a positive pressure, bounces back, and returns from the downstream end of the intake duct to the unpurified chamber and the purification chamber. In utilizing the pulsating effect, further improvement in intake efficiency is sought.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an air cleaner that can further improve intake efficiency.

According to the first aspect of the present invention, a cleaner case that forms an unpurified chamber that communicates with the outside air and a purification chamber that communicates with the combustion chamber of the engine to which purified air is supplied, and the unpurified chamber and the purification chamber A cleaner element disposed between the cleaner case and the outside air; and an intake duct fixed to the cleaner case and having an upstream end opening to a space outside the cleaner case and a downstream end facing the unpurified chamber. In the air cleaner, a wall body is disposed at a downstream end of the intake duct and extends in the circumferential direction while maintaining a distance from the outer peripheral surface of the intake duct.

According to the second aspect, in addition to the configuration of the first aspect, the air cleaner has a flange that spreads outward from the outer peripheral surface of the intake duct and integrates the upstream end of the wall body on the outer peripheral surface of the intake duct. Have.

According to the third aspect, in addition to the configuration of the first or second aspect, the downstream end of the wall body is in the same virtual plane as the downstream end of the intake duct, or the downstream end is in the virtual plane. Cross.

According to the fourth aspect, in addition to the configuration of any one of the first to third aspects, the air cleaner is continuous with the wall body in the circumferential direction, and integrates the wall body with the outer peripheral surface of the intake duct. To have a conjugate.

According to the fifth side surface, in addition to the configuration of the fourth side surface, the gap formed by the outer peripheral surface of the intake duct and the inner peripheral surface of the wall body has a U-shaped end portion.

According to the sixth aspect, in addition to the configuration of any one of the first to third aspects, the wall body is continuous in the circumferential direction without interruption and is provided between the outer circumferential surface of the intake duct over the entire circumference in the circumferential direction. Form an interval.

According to the seventh aspect, in addition to the configuration of any one of the first to sixth aspects, the downstream end of the intake duct bends to face the cleaner element.

According to the first aspect, since the wall is arranged at the downstream end of the intake duct, when the negative pressure pressure wave propagates from the downstream end to the upstream end of the intake duct, the negative pressure pressure wave becomes It smoothly flows into the downstream end along the inner circumference of the downstream end without vortexing backflow. The pressure wave efficiently propagates toward the upstream end. The pressure wave has its phase inverted at the upstream end of the intake duct, and the positive pressure pressure wave propagates from the upstream end to the downstream end. When the pressure wave flows into the unpurified chamber from the downstream end, the pressure wave smoothly flows into the unpurified chamber without being affected by the wall body. In this way, the intake efficiency can be increased. Therefore, driving performance is improved.

According to the second aspect, since the wall body is integrated with the intake duct, the formability can be enhanced and the productivity can be improved.

According to the third aspect, it is possible to effectively increase the intake efficiency while reducing the generation of the spiral backflow toward the inner circumference at the downstream end.

According to the fourth aspect, on the outer peripheral surface of the intake duct, the wall body can be omitted in the region of the combined body. Despite the wall arrangement, the profile of the downstream end of the intake duct can be reduced as much as possible. As a result, the cleaner case can be downsized.

According to the fifth aspect, since the end portion of the gap defined between the outer peripheral surface of the intake duct and the wall body is formed by the curved surface, the occurrence of turbulence is suppressed, and the intake efficiency is favorably enhanced. be able to.

According to the sixth aspect, the negative pressure wave can efficiently and efficiently flow into the downstream end of the intake duct.

According to the seventh aspect, unpurified air can flow into the unpurified chamber and effectively flow into the cleaner element.

FIG. 1 is a side view schematically showing an overall image of a saddle type vehicle (motorcycle) according to an embodiment of the present invention. (First embodiment) FIG. 2 is an enlarged cross-sectional view of the air cleaner according to the first embodiment taken along line 2-2 of FIG. (First embodiment) FIG. 3 is an enlarged vertical sectional view taken along line 3-3 of FIG. (First embodiment) FIG. 4 is an enlarged vertical sectional view taken along line 4-4 of FIG. (First embodiment) FIG. 5 is a conceptual diagram schematically showing how pressure flows in and out at the downstream end of the suction duct. (First embodiment) FIG. 6 is an enlarged cross-sectional view of the air cleaner according to the second embodiment. (Second embodiment) FIG. 7 is an enlarged sectional view taken along line 7-7 of FIG. (Second embodiment) FIG. 8 corresponds to FIG. 7 and is an enlarged cross-sectional view of an air cleaner according to a modified example of the second embodiment. (Second embodiment)

29 ... Engine 39 ... Air cleaner 45 ... Cleaner case 49 ... Cleaner element 52a ... Unpurified chamber 52b ... Purification chamber 54 ... Intake duct 54a ... Upstream end 54b ... Downstream end 65 ... Wall 66 ... Flange 71 ... Air cleaner 72 ... Cleaner Case 73 ... Cleaner element 75a ... Unpurified chamber 75b ... Purification chamber 76 ... Intake duct 76a ... Upstream end 76b ... Downstream end 85 ... Wall 86 ... Combined 86a ... Curvature surface 87 ... Flange S2 ... Interval

An embodiment of the present invention will be described below with reference to the accompanying drawings. In the following description, the front-rear direction, the up-down direction, and the left-right direction are the directions viewed by an occupant on the motorcycle.
(1) Air cleaner according to the first embodiment

FIG. 1 schematically shows a scooter type motorcycle according to an embodiment of a saddle type vehicle. The motorcycle 11 includes a vehicle body frame 12 and a vehicle body cover 13 mounted on the vehicle body frame 12. The head pipe of the vehicle body frame 12 rotatably supports a front fork 15 and a rod-shaped steering handle 16 that support the front wheels WF around the axle 14.

The passenger seat 17 is mounted on the vehicle body cover 13 above the rear frame. The vehicle body cover 13 includes a front cover 21 that covers the head pipe from the front, a leg shield 22 that continues from the front cover 21, and a lower end of the leg shield 22 that is continuous between the occupant seat 17 and the front wheels WF and above the main frame. And a step cover 23 arranged on the rear frame, and a rear cover 24 for supporting the occupant seat 17 on the rear frame.

A unit swing type drive unit 25 is arranged in the space below the rear cover 24. The drive unit 25 is connected to a bracket 26, which is connected to the front end of the rear frame, via a link 27 so as to be vertically swingable. A rear wheel WR is supported at the rear end of the drive unit 25 so as to be rotatable around a horizontal axis. A rear cushion unit 28 is arranged between the rear frame and the drive unit 25 at a position apart from the link 27 and the bracket 26. The drive unit 25 includes an air-cooled single-cylinder engine 29, and a transmission case 31 that is coupled to an engine body 29a of the engine 29 and houses a transmission device that transmits the output of the engine 29 to the rear wheels WR.

The engine body 29a of the engine 29 includes a crankcase 33 that rotatably supports a crankshaft about a rotation axis, a cylinder block 34 connected to the crankcase 33, a cylinder head 35 connected to the cylinder block 34, and a cylinder. A head cover 36 coupled to the head 35. The cylinder block 34 is formed with a cylinder that guides the linear reciprocating motion of the piston. A combustion chamber is formed between the piston and the cylinder head 35. The intake stroke, compression stroke, combustion stroke and exhaust stroke of the engine 29 are repeated according to the linear reciprocating motion of the piston.

An intake device 37 connected to the intake passage leading to the combustion chamber and an exhaust device 38 connected to the exhaust passage leading to the combustion chamber are coupled to the cylinder head 35. The intake device 37 includes an air cleaner 39 supported by the transmission case 31, and a throttle body 41 arranged between the air cleaner 39 and the cylinder head 35. In the throttle body 41, the flow rate of purified air supplied from the air cleaner 39 is adjusted by the action of the throttle.

A fuel injection valve 42 is attached to the upper side wall of the cylinder head 35. Fuel is injected from the fuel injection valve 42 into the purified air to form an air-fuel mixture. An intake valve that controls the opening and closing of the intake passage is arranged in the cylinder head 35. In the intake stroke of the engine 29, the piston moves away from the cylinder head 35 in conjunction with the opening operation of the intake valve, and negative pressure is generated in the intake passage. Thus, the air-fuel mixture is introduced into the combustion chamber.

The exhaust device 38 includes an exhaust pipe 43 that extends rearward from a lower side wall of the cylinder head 35 through a lower portion of the engine body 29a, and an exhaust muffler that is connected to a downstream end of the exhaust pipe 43 and is connected to the crankcase 33 (illustrated in the drawing). )) And. The air after combustion is discharged from the combustion chamber through the action of the exhaust valve.

The air cleaner 39 according to the first embodiment is a cleaner case 45 that forms an internal space that communicates with the supply destination (engine 29) of the outside air and purified air, and is fixed to the cleaner case 45 so as to be outside in the vehicle width direction of the motorcycle 11. And a case cover 46 that covers the outer surface of the cleaner case 45. The case cover 46 is formed with an opening 47 that connects a space of outside air to a standby chamber defined by the outer surface of the cleaner case 45 and the case cover 46. The opening 47 of the case cover 46 is provided with a louver 48 formed of a plurality of blades extending in parallel to a plane orthogonal to the rotation axis of the rear wheel WR.

As shown in FIG. 2, the cleaner case 45 includes a first body 45a and a second body 45a, which are joined together at a mating surface along a vertical plane VP parallel to an imaginary plane orthogonal to the rotation axis of the crankshaft. 45b. The first container body 45a and the second container body 45b are molded from, for example, a resin material. A partition wall 51 holding the cleaner element 49 is sandwiched between the first container 45a and the second container 45b. The cleaner case 45 forms an unpurified chamber 52a communicating with the outside air space between the partition wall 51 and the first container 45a, and an engine 29, which is a supply destination of purified air, between the partition wall 51 and the second container 45b. To form a purification chamber 52b that communicates with the combustion chamber. In this way, the inner space of the cleaner case 45 is partitioned into the unpurified chamber 52a and the purified chamber 52b. The cleaner element 49 is arranged between the unpurified chamber 52a and the purified chamber 52b. The outside air passes through the cleaner element 49, is purified, and is introduced into the purification chamber 52b.

The cleaner case 45 includes an intake duct 54 having an upstream end 54a that opens in the space outside the cleaner case 45 in the standby chamber 53 and a downstream end 54b that faces the unpurified chamber 52a in the cleaner case 45, and the cleaner case 45. An upstream end 55a located inside the purification chamber 52b opens to the internal space of the cleaner case 45, and a downstream end 55b outside the cleaner case 45 is fixed to the connecting tube 55 connected to the throttle body 41. The intake duct 54 and the connecting tube 55 can be molded from a resin material. The intake duct 54 and the connecting tube 55 have the flexibility to be deformed manually.

The intake duct 54 extends in the front-rear direction of the vehicle in parallel with the partition wall 51, and penetrates the outer wall of the first device body 45a at the mounting port 56. On the outer wall surface of the intake duct 54, a pair of fixing flanges 57 that sandwich the outer wall of the first container 45a from the axial direction are formed. The intake duct 54 is axially fixed to the through hole 56 of the first body 45a by the action of the fixing flange 57.

The outer wall of the first body 45 a is located on the front side of the vehicle and outside the intake duct 54 in the vehicle width direction, and is recessed on the rear side of the vehicle to form a standby chamber 53 between the inner surface of the case cover 46. The downstream end 54b of the intake duct 54 is bent in the horizontal direction so as to face the cleaner element 49.

Referring also to FIG. 3, at the upstream end 54a of the intake duct 54, an inner wall surface 58 that expands toward the upstream end 54a is defined. On the other hand, the outer wall surface 59 of the upstream end 54a is partitioned into a cylindrical surface having a uniform diameter. At the upstream end 54a of the intake duct 54, a wall body 61 that extends in the circumferential direction while maintaining a space S1 between the outer periphery (outer wall surface 59) of the intake duct 54 is arranged. The wall 61 defines an inner peripheral surface and an outer peripheral surface that are coaxial with the outer wall surface 59 of the upstream end 54a. As a result, the upstream end 54a of the intake duct 54 can be axially removed during resin molding of the intake duct 54.

The intake duct 54 is formed with a flange 62 that extends outward from the outer wall surface of the intake duct 54 and integrates the downstream end of the wall body 61 on the outer wall surface of the intake duct 54. The upstream end of the wall body 61 is in contact with a virtual plane including the upstream end 54 a of the intake duct 54. That is, the upstream end of the wall body 61 and the upstream end 54a of the intake duct 54 are on the same virtual plane. In addition, the upstream end of the wall body 61 may extend rearward of a virtual plane including the upstream end 54a of the intake duct 54 and intersect the virtual plane. The wall body 61 is continuous in the circumferential direction without interruption, and forms a space S1 between the wall body 61 and the outer wall surface of the intake duct 54 over the entire circumference in the circumferential direction.

At the downstream end 54b of the intake duct 54, an inner wall surface 63 that expands toward the downstream end 54b is defined. On the other hand, the outer wall surface 64 of the downstream end 54b is partitioned into a cylindrical surface having a uniform diameter. Referring also to FIG. 4, at the downstream end 54b of the intake duct 54, a wall body 65 that extends in the circumferential direction while maintaining a distance S2 from the outer periphery (outer wall surface 64) of the intake duct 54 is arranged. The wall body 65 is formed of a cylindrical body 65a coaxial with the outer wall surface 64 of the downstream end 54b and a flat wall body 65b facing the inner surface of the first device body 45a and extending along a vertical surface. The space between the wall body 65 and the outer wall surface 64 of the intake duct 54 is narrowed by the flat wall body 65b. The outer diameter of the wall body 65 is reduced at the position of the flat wall body 65b. When molding the air intake duct 54, the downstream end 54b of the air intake duct 54 can be removed in the axial direction.

The intake duct 54 is formed with a flange 66 that extends outward from the outer wall surface of the intake duct 54 and integrates the upstream end of the wall body 65 on the outer wall surface of the intake duct 54. The downstream end of the wall body 65 contacts the virtual plane VP including the downstream end 54b of the intake duct 54. That is, the downstream end of the wall body 65 and the downstream end 54b of the intake duct 54 are on the same virtual plane VP. In addition, the downstream end of the wall body 65 may extend forward of the virtual plane VP including the downstream end 54b of the intake duct 54 and intersect the virtual plane VP. The wall body 65 is continuous in the circumferential direction without interruption, and forms a space S2 between the outer wall surface of the intake duct and the entire circumference in the circumferential direction.

Next, the operation of this embodiment will be described. When the engine 29 operates, the intake stroke, compression stroke, combustion stroke, and exhaust stroke of the engine 29 are repeated according to the linear reciprocating motion of the piston. In the intake stroke of the engine 29, the piston moves away from the cylinder head 35 in conjunction with the opening operation of the intake valve, and negative pressure is generated in the intake passage. The mixture is introduced into the combustion chamber.

The pulsating effect is used in the intake of the engine 29. When the intake valve is opened, a negative pressure wave is generated and propagates at a sonic velocity from the downstream end 54b of the intake duct 54 to the upstream end 54a of the intake duct 54 through the purified chamber 52b and the unpurified chamber 52a. The pressure wave reverses at the upstream end 54a of the intake duct 54 to become a positive pressure and bounces back from the downstream end 54b of the intake duct 54 to the unpurified chamber 52a and the purified chamber 52b.

At this time, since the wall body 65 is arranged at the downstream end 54b of the intake duct 54, when the negative pressure wave propagates from the downstream end 54b to the upstream end 54a of the intake duct 54, the negative pressure wave of FIG. ), The negative pressure wave smoothly flows into the downstream end 54b along the inner circumference of the downstream end 54b without vortexing backflow. The pressure wave efficiently propagates toward the upstream end 54a. After that, the pressure wave is inverted in phase at the upstream end 54a of the intake duct 54, and the positive pressure pressure wave propagates from the upstream end 54a to the downstream end 54b. When the pressure wave flows into the unpurified chamber 52a from the downstream end 54b, the pressure wave smoothly flows into the unpurified chamber 52a without being influenced by the wall body 65, as shown in FIG. 5B. In this way, the intake efficiency can be increased. Therefore, driving performance is improved.

If the wall 65 is not formed at the downstream end 54b of the intake duct 54, the negative pressure wave is shown in FIG. 5C when propagating from the downstream end 54b of the intake duct 54 toward the upstream end 54a. As described above, the negative pressure wave swirls back along the inner circumference of the downstream end 54b, and the smooth inflow to the downstream end 54b is prevented. As a result, the intake efficiency is reduced. Therefore, improvement of driving performance cannot be expected.

In the intake duct 54, the upstream end of the wall body 61 extends outward from the outer wall surface of the intake duct 54 and is integrated with the outer wall surface of the intake duct 54 by a flange 62. In this way, since the wall body 61 is integrated with the intake duct 54, the moldability is enhanced and the productivity is improved.

The downstream end of the wall 65 contacts the virtual plane VP including the downstream end 54b of the intake duct 54. As a result, the intake efficiency is effectively increased as compared with the case where the downstream end of the wall body 61 does not reach the virtual plane VP including the downstream end 54b of the intake duct 54. In addition, even if the downstream end of the wall 61 intersects with the virtual plane VP including the downstream end 54b of the intake duct 54, the downstream end of the wall 61 does not reach the virtual plane VP including the downstream end 54b of the intake duct 54. The intake efficiency is effectively increased as compared with the case.

In the air cleaner 39 according to the present embodiment, the wall body 61 is continuous in the circumferential direction without interruption, and the space S2 is formed between the outer wall surface of the intake duct 54 over the entire circumference in the circumferential direction. Therefore, the negative pressure wave can flow into the downstream end 54b of the intake duct 54 with maximum efficiency.

In the present embodiment, since the downstream end 54b of the intake duct 54 is bent so as to be directed to the cleaner element 49, the unpurified air can flow into the unpurified chamber 52a and effectively hit the cleaner element 49.
(2) Air cleaner according to the second embodiment

As shown in FIG. 6, the air cleaner 71 according to the second embodiment includes a cleaner case 72 that forms an internal space that communicates with a supply destination (engine 29) of outside air and purified air. The cleaner case 72 is connected to the upper first body 72a from below at the mating surface along a front rising virtual plane HP extending horizontally in parallel to the rotation axis of the crankshaft. It has a second body 72b and a third body 72c which is joined to the second body 72b from below at a mating surface along a front-down virtual plane JP that spreads in the horizontal direction parallel to the rotation axis of the crankshaft. The first container body 72a, the second container body 72b, and the third container body 72c are molded from, for example, a resin material. A cleaner element 73 is sandwiched between the first container 72a and the second container 72b. The cleaner element 73 is held by a partition wall 74 formed integrally with the second container 72b. The cleaner case 72 forms an unpurified chamber 75a that communicates with the outside air space between the partition wall 74 and the first device body 72a, and supplies clean air between the second device body 72b and the third device body 72c. A purifying chamber 75b communicating with the combustion chamber of an engine 29 is formed. In this way, the inner space of the cleaner case 72 is partitioned into the unpurified chamber 75a and the purified chamber 75b. The cleaner element 74 is arranged between the unpurified chamber 75a and the purified chamber 75b. The outside air passes through the cleaner element 74 to be purified and introduced into the purification chamber 75b.

The cleaner case 72 has an upstream end 76a that opens below the passenger seat (not shown) to the space outside the cleaner case 72, and a downstream end 76b that faces the unpurified chamber 75a in the cleaner case 45. And the connecting tube 77 that is opened to the internal space of the cleaner case 72 at the upstream end 77a located inside the purification chamber 75b of the cleaner case 72 and is connected to the throttle body 41 at the downstream end 77b outside the cleaner case 72. To be done. The intake duct 76 and the connecting tube 77 can be molded from a resin material. The intake duct 76 and the connecting tube 77 have the flexibility that they can be deformed manually.

The intake duct 76 extends in the front-rear direction of the vehicle in parallel with the partition wall 74, and penetrates the outer wall of the first device body 72a at the attachment port 78. A pair of fixing flanges 79 are formed on the outer wall surface of the intake duct 76 so as to sandwich the outer wall of the first body 72a from the axial direction. The intake duct 76 is axially fixed to the through hole 78 of the first body 72a by the action of the fixing flange 79.

The outer wall of the first body 72a is located above the intake duct 76 on the front side of the vehicle, and recessed below the intake duct 76 on the rear side of the vehicle. The upstream end 76a of the intake duct 76 is bent in the vertical direction so as to move away from the upper occupant seat.

At the upstream end 76a of the intake duct 76, an inner wall surface 81 that expands toward the upstream end 76a is defined. At the upstream end 76a of the intake duct 76, a wall body 82 that extends in the circumferential direction while maintaining a space S1 between the intake duct 76 and the outer periphery (outer wall surface) of the intake duct 76 is arranged. The space S1 is constant at least from the downstream end to the upstream end of the wall body 82, and partially increases from the downstream end to the upstream end of the wall body 82. As a result, the upstream end 76a of the intake duct 76 can be axially demolded when the intake duct 76 is molded with resin.

The intake duct 76 is formed with a flange 83 that extends outward from the outer wall surface of the intake duct 76 and integrates the downstream end of the wall body 82 on the outer wall surface of the intake duct 76. The upstream end of the wall body 82 is in contact with an imaginary plane including the upstream end 76 a of the intake duct 76. That is, the upstream end of the wall body 82 and the upstream end 76a of the intake duct 76 are on the same virtual plane. In addition, the upstream end of the wall body 82 may extend rearward of a virtual plane including the upstream end 76a of the intake duct 76 and intersect the virtual plane. The wall body 82 is continuous in the circumferential direction without interruption, and forms a space S1 between the wall body 82 and the outer wall surface of the intake duct 76 over the entire circumference in the circumferential direction.

At the downstream end 76b of the intake duct 76, an inner wall surface 84 that expands toward the downstream end 76b is defined. Referring also to FIG. 7, at the downstream end 76b of the intake duct 76, a wall body 85 that extends in the circumferential direction while maintaining a distance S2 from the outer circumference (outer wall surface) of the intake duct 76 is arranged. The intake duct 76 is continuous with the wall body 85 in the circumferential direction, and has a combined body 86 that integrates the wall body 85 on the outer peripheral surface of the intake duct 76. The outer surface of the combined body 86 is divided into a plane facing the inner surface of the first container 72 a and the cleaner element 73. Therefore, the outer diameter of the wall body 85 is reduced at the position of the joint body 86. When molding the air intake duct 76, the downstream end 76b of the air intake duct 76 can be removed in the axial direction.

The intake duct 76 is formed with a flange 87 that extends outward from the outer wall surface of the intake duct 76 and integrates the upstream end of the wall body 65 on the outer wall surface of the intake duct 76. The downstream end of the wall body 85 is in contact with the virtual plane VQ including the downstream end 76b of the intake duct 76. That is, the downstream end of the wall body 85 and the downstream end 76b of the intake duct 76 are on the same virtual plane VQ. In addition, the downstream end of the wall body 85 may extend forward of the virtual plane VQ including the downstream end 76b of the intake duct 76 and intersect the virtual plane VQ.

At the downstream end 76b of the intake duct 76, the outer surface of the combined body 86 is divided into a plane facing the inner surface of the first container 72a and the cleaner element 73. Therefore, the outer diameter of the wall body 85 is reduced at the position of the joint body 86. As a result, the downstream end 76b of the intake duct 76 can be compactly accommodated in the space in the height direction.

According to the present embodiment, as in the first embodiment, since the wall body 85 is arranged at the downstream end 76b of the intake duct 76, a negative pressure wave is generated from the downstream end 76b of the intake duct 76 to the upstream end 76a. When propagating toward, the negative pressure wave smoothly flows into the downstream end 76b along the inner circumference of the downstream end 76b without being swirled backward. The pressure wave efficiently propagates toward the upstream end 76a. In this way, the intake efficiency is increased. Therefore, driving performance is improved.

In the intake duct 76, the upstream end of the wall body 85 extends outward from the outer wall surface of the intake duct 76 and is integrated with the outer wall surface of the intake duct 76 by a flange 87. In this way, since the wall body 85 is integrated with the intake duct 76, the formability is enhanced and the productivity is improved.

The downstream end of the wall 82 contacts the virtual plane VQ including the downstream end 76b of the intake duct 76. As a result, the intake efficiency is effectively increased as compared with the case where the downstream end of the wall body 82 does not reach the virtual plane VQ including the downstream end 76b of the intake duct 76. In addition, even if the downstream end of the wall body 82 intersects with the virtual plane VQ including the downstream end 76b of the intake duct 76, the downstream end of the wall body 85 does not reach the virtual plane VQ including the downstream end 76b of the intake duct 76. The intake efficiency is effectively increased as compared with the case.

In the air cleaner 71 according to the present embodiment, the intake duct 76 has a joint body 86 that is continuous with the wall body 85 in the circumferential direction and that integrates the wall body 85 on the outer wall surface of the intake duct 76. On the outer wall surface of the intake duct 76, the wall body 85 is omitted in the region of the joint body 86. Despite the arrangement of the wall body 85, the outer shape of the downstream end 76b of the intake duct 76 is reduced as much as possible. As a result, the cleaner case 72 can be downsized.

As shown in FIG. 8, the combined body 86 may have a concave curved surface 86 a that is continuous from the outer peripheral surface of the intake duct 76 to the inner side surface of the wall body 85. The curved surface 86 a draws a U shape on the virtual plane VQ including the downstream end of the wall body 85. Since the end portion of the gap defined between the outer wall surface of the intake duct 76 and the wall body 85 is formed by the curved surface 86a, the occurrence of turbulence is suppressed, and the intake efficiency can be favorably enhanced.

Claims

A cleaner case (45; 72) forming an unpurified chamber (52a; 75a) that communicates with the outside air and a purified chamber (52b; 75b) that communicates with the combustion chamber of the engine (29) to which purified air is supplied.
A cleaner element (49; 73) disposed between the unpurified chamber (52a; 75a) and the purified chamber (52b; 75b) for purifying outside air;
An upstream end (54a; 76a) fixed to the cleaner case (45; 72) and opening to a space outside the cleaner case (45; 72), and a downstream end facing the unpurified chamber (52a; 75a). An air cleaner (39; 71) comprising an intake duct (54; 76) having (54b; 76b),
At the downstream end (54b; 76b) of the intake duct (54; 76), a wall body (65; which maintains a space (S2) from the outer peripheral surface of the intake duct (54; 76) and extends in the circumferential direction. 85) is arranged in the air cleaner.
The air cleaner according to claim 1, wherein the upstream end of the wall body (65; 85) extends outward from the outer peripheral surface of the intake duct (54; 76) and extends to the outer peripheral surface of the intake duct (54; 76). An air cleaner characterized by having integral flanges (66; 87).
The air cleaner according to claim 1 or 2, wherein the downstream end of the wall body (65; 85) is in the same imaginary plane (VP; VQ) as the downstream end (54b; 76b) of the intake duct (54; 76). An air cleaner characterized in that it is on the top or the downstream end (54b; 76b) intersects with the virtual plane (VP; VQ).
The air cleaner according to any one of claims 1 to 3, which is continuous with the wall body (85) in a circumferential direction, and integrates the wall body (85) with an outer peripheral surface of the intake duct (76). An air cleaner having a combination (86).
The air cleaner according to claim 4, wherein the gap formed between the outer peripheral surface of the intake duct (76) and the inner peripheral surface of the wall body (85) has a U-shaped end portion. air cleaner.
The air cleaner according to any one of claims 1 to 3, wherein the wall body (65) is continuous in the circumferential direction without interruption and between the outer peripheral surface of the intake duct (54) over the entire circumference in the circumferential direction. An air cleaner characterized by forming a space (S2).
The air cleaner according to any one of claims 1 to 6, wherein the downstream end (54b) of the intake duct (54) is bent so as to be directed toward the cleaner element (49).