Off-road vehicles

Abstract

Improve the air cleaner to enhance vehicle performance. [Solution] The air cleaner includes an air cleaner case 41 that defines an internal space, and an air cleaner element 42 housed in the air cleaner case, which includes an air filter 42b that divides the internal space into a dirty area and a clean area. The air cleaner case includes an inner surface that defines the internal space, an inlet 61e disposed on the inner surface and facing the air filter via the dirty area, and an outlet 63a facing the clean area. The air filter extends in a predetermined direction. The inlet has a shape that extends in the predetermined direction.

Description

Technical Field

[0001] The present disclosure relates to an off-road vehicle equipped with an air cleaner.

Background Art

[0002] An off-road vehicle equipped with an internal combustion engine includes an intake passage that supplies outside air to the internal combustion engine for combustion. An off-road vehicle equipped with a continuously variable transmission includes an intake passage that supplies outside air to the continuously variable transmission for cooling. An air cleaner for purifying air may be provided in those intake passages.

[0003] Patent Document 1 discloses an air cleaner provided in an intake passage of a vehicle. The air cleaner includes an air cleaner case and an air filter housed in the air cleaner case. The air filter divides the internal space of the air cleaner case into a dirty region and a clean region. The intake duct on the upstream side of the air cleaner communicates with the dirty region of the internal space of the air cleaner case, and the intake duct on the downstream side of the air cleaner communicates with the clean region of the internal space of the air cleaner case.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Although the air filter creates resistance to the intake air flow, smooth intake air is desired to improve the performance of the internal combustion engine or the continuously variable transmission. Also, in order to maintain the purification performance of the air cleaner, it is desired that the intake air passes through the air filter uniformly.

[0006] Therefore, one aspect of the present disclosure aims to improve the air cleaner to enhance the performance of the vehicle. [Means for solving the problem]

[0007] An off-road vehicle according to one aspect of the present disclosure comprises an intake duct defining a dirty air passage and an air cleaner connected to the intake duct. The air cleaner includes an air cleaner case defining an internal space and an air cleaner element housed in the air cleaner case, which includes an air filter that divides the internal space into a dirty area and a clean area. The air cleaner case includes an inner surface defining the internal space, an inlet disposed on the inner surface and facing the air filter through the dirty area, and an outlet facing the clean area. The air filter extends in a predetermined direction. The inlet has a shape that extends in the predetermined direction.

[0008] An off-road vehicle according to another aspect of the present disclosure comprises an intake duct defining a dirty passage and an air cleaner connected to the intake duct. The air cleaner includes an air cleaner case defining an internal space and an air cleaner element housed in the air cleaner case, which includes an air filter that divides the internal space into a dirty area and a clean area. The air cleaner case includes an inner surface defining the internal space, an inlet disposed on the inner surface and facing the air filter through the dirty area, and an outlet facing the clean area. The air filter extends in a predetermined direction. The size of the inlet in the predetermined direction is greater than half the size of the air filter in the predetermined direction. [Effects of the Invention]

[0009] According to one aspect of this disclosure, the performance of the vehicle can be improved in terms of intake. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a right side view of an off-road vehicle according to an embodiment. [Figure 2] Figure 2 is a perspective view of the intake structure of the vehicle shown in Figure 1, viewed from the right rear of the vehicle. [Figure 3] Figure 3 is a perspective view of the intake structure shown in Figure 2, viewed from the inside in the vehicle width direction. [Figure 4] Figure 4 is a side view of the air cleaner and other components shown in Figure 2. [Figure 5] Figure 5 is a longitudinal cross-sectional view of the air cleaner shown in Figure 4. [Figure 6] Figure 6 is a side view of the air cleaner shown in Figure 5, viewed from a direction directly facing the inlet cylinder. [Figure 7] Figure 7 is a perspective view of the rear of the vehicle shown in Figure 1, viewed from the right rear. [Figure 8] Figure 8A is a cross-sectional view showing the fasteners of the first protective cover. Figure 8B is a cross-sectional view showing the engagement structure of the second protective cover. [Figure 9] Figure 9 is a longitudinal cross-sectional view of a modified air cleaner. [Modes for carrying out the invention]

[0011] The embodiments will be described below with reference to the drawings. In the following description, unless otherwise specified, directions are based on the direction of the off-road vehicle 1, with the front-rear direction corresponding to the vehicle length direction and the left-right direction corresponding to the vehicle width direction.

[0012] Figure 1 is a right side view of an off-road vehicle 1 according to an embodiment. As shown in Figure 1, the off-road vehicle 1 comprises a body frame 2, a pair of left and right front wheels 3 supporting the front of the body frame 2, and a pair of left and right rear wheels 4 supporting the rear of the body frame 2. The body frame 2 is a pipe frame formed by connecting a plurality of pipes to each other. The tires of the front wheels 3 and rear wheels 4 are balloon tires for off-road driving. The space between the left and right front wheels 3 is covered from above by a front cover 5.

[0013] Behind the front cover 5, an occupant seat 6 is positioned, supported by the vehicle frame 2. The vehicle frame 2 includes a cabin frame 2a, etc., which surrounds the cabin C where the occupant seat 6 is located. The cabin C is exposed to the outside. Side doors 7 are positioned on the sides of the cabin C. A dashboard 8 is positioned in front of the occupant seat. A handle 9 is provided on the dashboard 8.

[0014] Behind the cabin frame 2a is a cargo bed 10 supported by the rear frame 2b of the vehicle body frame 2. The cargo bed 10 defines a concave loading space that is open to the outside. Behind the cabin frame 2a and below the cargo bed 10 is the engine room ER. The engine room ER is partially covered by a rear side cowl 11 that is exposed to the outside in the width direction of the vehicle. The rear side cowl 11 is supported by the rear frame 2b of the vehicle body frame 2.

[0015] The engine room ER houses an internal combustion engine 12 as the prime mover and a continuously variable transmission that changes the driving force output by the internal combustion engine 12. The internal combustion engine 12 is supported by the rear frame 2b. The internal combustion engine 12 is located approximately in the center of the vehicle width direction of the vehicle 1. An intake system 14 is connected to the intake port of the internal combustion engine 12. An exhaust system 15 is connected to the exhaust port of the internal combustion engine 12. The intake box 21, which constitutes the intake system 14, is located behind the cabin C and in front of the cargo bed 10. The intake box 21 is located higher than the side door 7.

[0016] The air cleaner 23 that constitutes the intake system 14 is disposed lower than the intake box 21. The air cleaner 23 is covered by the rear side cowl 11 from the outer side in the vehicle width direction and is hidden in a side view of the off-road vehicle 1. That is, in a side view of the vehicle, the rear side cowl 11 overlaps the air cleaner 23. The air cleaner 23 is disposed higher than the rear wheel 4. The intake box 21 and the air cleaner 23 are disposed on one side in the vehicle width direction of the vehicle 1, for example, on the right side of the vehicle 1. The rear side cowl 11 has a notch 11a that partially exposes the engine room ER to the outer side in the vehicle width direction.

[0017] FIG. 2 is a perspective view of the intake structure 20 of the vehicle 1 in FIG. 1 as viewed from the right rear of the vehicle. FIG. 3 is a perspective view of the intake structure 20 in FIG. 2 as viewed from the inner side in the vehicle width direction. As shown in FIGS. 2 and 3, the intake structure 20 that constitutes the intake system 14 includes an intake box 21, a first intake duct 22, an air cleaner 23, a second intake duct 24, and a supercharger 25. Note that the intake air sent from the supercharger 25 is supplied to the intake port of the internal combustion engine 12 via a third intake duct, an intercooler, a fourth intake duct, an intake tank, and a throttle body.

[0018] The intake box 21 includes a box 21a, and filters 21b and 21c attached to the box 21a. The box 21a defines an internal space and has two openings that open the internal space to the outside. The filters 21b and 21c close the respective openings of the box 21a. Due to the negative pressure generated in the intake port of the internal combustion engine 12, outside air is sucked into the internal space of the intake box 21 as intake air through the filters 21b and 21c. The filters 21b and 21c roughly remove foreign matters from the intake air upstream of the air cleaner 23.

[0019] The intake air of the intake air box 21 flows through the first intake duct 22, the air cleaner 23, the second intake duct 24, and the supercharger 25 in this order. The intake air box 21 is connected to the air cleaner 23 by the first intake duct 22. The first intake duct 22 defines a dirty flow path through which the intake air before being purified by the air cleaner 23 flows. The first intake duct 22 includes a resin duct.

[0020] The air cleaner 23 has a cylindrical shape having an axis X, and the axis X of the air cleaner 23 is substantially upward at an angle within a range of less than 45°, preferably less than 30°, with respect to the vertical line V when viewed in the horizontal direction. Thereby, the air cleaner 23 can be formed in a shape extending in the vertical direction, and the occupied space of the air cleaner 23 in the horizontal direction in the vehicle 1 is reduced. Details of the first intake duct 22 and the air cleaner 23 will be described later.

[0021] The air cleaner 23 is connected to the supercharger 25 by the second intake duct 24. The supercharger 25 is disposed below the air cleaner 23. The supercharger 25 is disposed at a height overlapping the internal combustion engine 12. The supercharger 25 is adjacent to the internal combustion engine 12. The supercharger 25 is, for example, a mechanical supercharger driven by power extracted from the internal combustion engine 12. The supercharger 25 includes a housing portion 25a that houses an impeller, and an inlet cover portion 25b that is fixed to the housing portion 25a so as to cover the intake inlet of the housing portion 25a. The housing portion 25a is made of metal. The inlet cover portion 25b is made of resin. Note that the supercharger 25 may be a turbocharger driven by the exhaust of the internal combustion engine 12.

[0022] The second intake duct 24 defines a clean flow path through which the intake air purified by the air cleaner 23 flows. The second intake duct 24 is disposed at a height overlapping the height range of the first intake duct 22. The second intake duct 24 overlaps the first intake duct 22 from the inner side in the vehicle width direction. The second intake duct 24 has a first portion 24a, a second portion 24b, and a third portion 24c.

[0023] The first portion 24a of the second intake duct 24 protrudes upward from the air cleaner 23. The second portion 24b of the second intake duct 24 curves downward from the first portion 24a. That is, the second portion 24b has an inverted U shape. The third portion 24c extends from the second portion 24b toward the supercharger 25. The upper parts of the first portion 24a, the second portion 24b, and the third portion 24c are made of resin. The lower part of the third portion 24c is made of metal.

[0024] The intake structure 20 is partially covered by at least one protective cover. This at least one protective cover covers at least the second intake duct 24 that defines the clean airflow path. In this embodiment, the intake structure 20 is partially covered by a first protective cover 31, a second protective cover 32, and a third protective cover 33. The protective covers 31-33 are interposed between the rear wheel 4 and the intake structure 20. Details of the protective covers 31-33 will be described later.

[0025] Figure 4 is a side view of the air cleaner 23 shown in Figure 2. Figure 5 is a longitudinal cross-sectional view of the air cleaner 23 shown in Figure 4. As shown in Figures 4 and 5, the air cleaner 23 has an air cleaner case 41 and an air cleaner element 42. The air cleaner element 42 includes a mesh-like support 42a with a cylindrical outer shape and an air filter 42b supported by the support 42a and arranged in a cylindrical shape. The air cleaner element 42 is housed in the air cleaner case 41.

[0026] The internal space S of the air cleaner case 41 is divided into a dirty region S1 and a clean region S2 by the air filter 42b of the air cleaner element 42. That is, the area upstream of the air cleaner element 42 in the internal space S is the dirty region S1, and the area downstream of the air cleaner element 42 in the internal space S is the clean region S2.

[0027] The air cleaner case 41 has a cylindrical shape with an axis X. The direction in which the axis X extends is referred to as the axial direction X. The air cleaner case 41 is made of resin. The air cleaner case 41 includes a case body 51 and a lid 52. The case body 51 has a case section 61, an inlet cylinder section 62, an inner outlet cylinder section 63, and an outer outlet cylinder section 64.

[0028] The case portion 61 has a cylindrical wall portion 61a having an axis X, an upper wall portion 61b that closes the upper side of the cylindrical wall portion 61a, and a maintenance opening 61c at the lower end of the cylindrical wall portion 61a that opens the internal space S downward. The maintenance opening 61c has a shape and size that allows the air cleaner element 42 to pass through. The maintenance opening 61c of the case portion 61 is closed from below by a lid 52. As shown in Figure 2, the lid 52 is connected to the case body 51 via a hinge 53. The lid 52 is locked to the case body 51 by a lock 54 when the maintenance opening 61c is closed. The operator can open the lid 52 by manually releasing the lock 54.

[0029] The cylindrical wall portion 61a of the case portion 61 has an inner circumferential surface 61d that defines an internal space S and faces the outer circumferential surface of the air filter 42b. The axis X of the case portion 61 coincides with the axis X of the air cleaner 23. The cylindrical wall portion 61a of the case portion 61 has an inlet 61e located on the inner circumferential surface 61d. The inlet 61e faces the air filter 42b via a dirty region S1. The axis X of the air filter 42b coincides with the axis X of the air cleaner 23. The dirty region S1 is defined between the inner circumferential surface 61d of the case portion 61 and the outer circumferential surface of the air filter 42b.

[0030] The inlet cylinder portion 62 protrudes outward from the cylindrical wall portion 61a of the case portion 61. The inlet cylinder portion 62 defines a flow path that communicates with the inlet 61e of the case portion 61. The flow path axis Y of the inlet cylinder portion 62 extends in a direction intersecting the axis X of the case portion 61. The direction in which the flow path axis Y extends can be called the flow path axis direction Y. The first intake duct 22 is connected to the inlet cylinder portion 62.

[0031] The inlet cylinder portion 62 has a tab 62a protruding from its outer surface. The first intake duct 22 has a tab 22d that matches the tab 62a of the inlet cylinder portion 62. The tab 62a of the inlet cylinder portion 62 and the tab 22c of the first intake duct 22 are fastened together by a fastener 27.

[0032] The upper wall portion 61b of the case portion 61 has an outlet 61f. The inner outlet cylinder portion 63 protrudes from the upper wall portion 61b toward the internal space S and defines a flow path that communicates with the outlet 61f. The inner outlet cylinder portion 63 has an outlet 63a at its lower end that faces the clean area S2. The outlet 63a faces the clean area S2 and communicates with the clean flow path of the second intake duct 24. The outlet 63a is located on the upper side in the axial direction X of the case body 51, and the maintenance opening 61c is located on the other side in the axial direction X of the case body 51. The area of ​​the inlet 61e is larger than the area of ​​the outlet 63a.

[0033] The outer outlet cylinder portion 64 protrudes outward from the upper wall portion 61b on the same axis as the inner outlet cylinder portion 63, defining a flow path that communicates with the outlet 61f. The second intake duct 24 is connected to the outer outlet cylinder portion 64. The inner outlet cylinder portion 63 and the outer outlet cylinder portion 64 are located on the upper part of the case body 51. The axes X of the inner outlet cylinder portion 63 and the outer outlet cylinder portion 64 coincide with the axis X of the case portion 61. The outlet 61f has a circular shape, and the inner outlet cylinder portion 63 and the outer outlet cylinder portion 64 have a cylindrical shape.

[0034] The air cleaner element 42 has a bottomed cylindrical shape with an upward opening. The upper end of the air cleaner element 42 is fitted into the inner outlet cylinder portion 63 in the axial direction X. The inner outlet cylinder portion 63 functions as an element support portion that supports the air cleaner element 42. When housed in the air cleaner case 41, the air cleaner element 42 is positioned at a distance from the cylindrical inner circumferential surface of the case body 51. That is, the dirty region S1 has an annular cross-section around the axis X. The clean region S2 is defined on the inner circumferential surface of the air filter 42b.

[0035] The intake air that flows from the first intake duct 22 into the inlet cylinder 62 flows into the internal space S from the inlet 61e, diffuses in the dirty region S1, passes through the air filter 42b, and enters the clean region S2. The intake air in the clean region S2 flows out to the second intake duct 24 from the outlet 63a.

[0036] Figure 6 is a side view of the air cleaner 23 of Figure 5, viewed from a direction directly facing the inlet cylinder 62. As shown in Figure 6, the inlet cylinder 62 has a shape that extends in the axial direction X when viewed from the flow path axis Y of the inlet cylinder 62. The inlet 61e of the case 61 has a shape that extends in the axial direction X when viewed from a viewpoint directly facing the inlet 61e. That is, the inner circumferential surface of the inlet cylinder 62 and the inlet 61e of the case 61 have a shape that extends in the axial direction X when viewed from a viewpoint where the area of ​​the inlet 61e is maximized.

[0037] Viewed from the flow path axis direction Y of the inlet 61e, the inlet 61e extends in the direction in which the air filter 42b extends. The direction in which the inlet 61e extends does not have to be exactly the same as the direction in which the air filter 42b extends; it may be slightly offset. The inlet 61e has an oval shape with a major axis extending in the axial direction X when viewed from a viewpoint directly facing the inlet 61e. The inner circumferential surface of the inlet cylinder 62 also has an oval shape with a major axis extending in the axial direction X when viewed from the flow path axis direction Y of the inlet cylinder 62. The air filter 42b extends in the axial direction X. Note that the inlet 61e is not limited to an oval shape. The inlet 61e may have an elliptical shape with a major axis extending in the axial direction X when viewed from a viewpoint directly facing the inlet 61e.

[0038] The size of the inlet 61e in the axial direction X is greater than half the size of the air filter 42b in the axial direction X. Preferably, the size of the inlet 61e in the axial direction X is 65% to 80% of the size of the air filter 42b in the axial direction X. If the inlet 61e has such a size in the axial direction X, the inlet 61e may have a circular shape when viewed from a viewpoint directly facing the inlet 61e.

[0039] The first intake duct 22 includes a downstream section 22a connected to the inlet cylindrical section 62, and an upstream section 22b located upstream of the downstream section 22a in the intake air flow direction of the intake duct 22. The flow path axis at the outlet of the downstream section 22a of the first intake duct 22 coincides with the flow path axis Y of the inlet cylindrical section 62. The outlet of the downstream section 22a of the first intake duct 22 has an oval shape that matches the inlet cylindrical section 62, that is, it has a shape that extends in the axial direction X when viewed from the flow path axis direction Y. The inlet of the upstream section 22b of the first intake duct 22 has a circular shape.

[0040] The cross-sectional shape of the first intake duct 22 changes as you move from the upstream side to the downstream side of the first intake duct 22. The outlet of the downstream section 22a of the first intake duct 22 is larger than the inlet of the upstream section 22b of the first intake duct 22. The major axis inner diameter of the outlet of the downstream section 22a of the first intake duct 22 is larger than the inner diameter of the inlet of the upstream section 22b of the first intake duct 22. The flow path cross-sectional area of ​​the downstream section 22a of the first intake duct 22 gradually expands towards the outlet of the downstream section 22a. The minimum flow path cross-sectional area of ​​the upstream section 22b of the first intake duct 22 is larger than the minimum flow path cross-sectional area of ​​the second intake duct 24. The minimum flow path cross-sectional area of ​​the upstream section 22b of the first intake duct 22 may also be larger than the maximum flow path cross-sectional area of ​​the second intake duct 24.

[0041] Figure 7 is a perspective view of the rear of vehicle 1 in Figure 1, taken from the right rear. As shown in Figure 7, the air cleaner 23 is covered by the rear side cowl 11 from the outside in the vehicle width direction and is hidden in a side view of the off-road vehicle 1. The rear side cowl 11 has a cutout 11a that partially exposes the engine room ER on the outside in the vehicle width direction. The off-road vehicle 1 does not have a wheel well facing the rear wheel 4. If the first to third protective covers 31 to 33 were absent, the intake box 21, first intake duct 22, air cleaner 23, second intake duct 24, and supercharger 25 would be directly facing the rear wheel 4. If the first to third protective covers 31 to 33 were absent, the cover 52 and lock 54 of the air cleaner 23 would be exposed when viewed from the diagonal side rear of the off-road vehicle 1.

[0042] The first to third protective covers 31 to 33 are positioned between the rear wheel 4 and the intake structure 20. This protects the intake structure 20 from stones and other debris kicked up by the rear wheel 4. The first to third protective covers 31 to 33 are spaced apart from the rear side cowl 11. The first to third protective covers 31 to 33 are made of resin.

[0043] As shown in Figures 2 and 7, the first protective cover 31 is a one-piece plate that covers the first intake duct 22, the air cleaner 23, and the second intake duct 24 together from the rear of the vehicle. The first protective cover 31 is not present in front of the first intake duct 22, the air cleaner 23, and the second intake duct 24 in the longitudinal direction of the vehicle. That is, the first protective cover 31 does not cover the first intake duct 22, the air cleaner 23, and the second intake duct 24 from the front of the vehicle. The first protective cover 31 includes a first intake duct protection section 31a that covers the first intake duct 22, a second intake duct protection section 31b that covers the second intake duct 24, and a bridge section 31c that covers the air cleaner 23.

[0044] The first intake duct protection part 31a has a curved shape that conforms to the outer surface of the first intake duct 22. The gap between the first intake duct protection part 31a and the first intake duct 22 is within the range of 1 mm to 5 mm. A gap of 1 mm or more between the first intake duct protection part 31a and the first intake duct 22 allows for tolerance absorption, while a gap of 5 mm or less effectively prevents the intrusion of foreign matter.

[0045] The second intake duct protection part 31b has a curved shape that follows the outer surface of the second intake duct 24. The second intake duct protection part 31b covers the resin portion of the second intake duct 24, but does not cover the metal portion which is the downstream portion of the second intake duct 24. The gap between the second intake duct protection part 31b and the second intake duct 24 is within the range of 1 mm to 5 mm. A gap of 1 mm or more between the second intake duct protection part 31b and the second intake duct 24 allows for tolerance absorption, while a gap of 5 mm or less effectively prevents the intrusion of foreign matter.

[0046] The bridge section 31c connects the first intake duct protection section 31a to the second intake duct protection section 31b. The bridge section 31c covers a portion of the air cleaner 23. The bridge section 31c has a shape that is closer to flat than the first intake duct protection section 31a and the second intake duct protection section 31b.

[0047] The first protective cover 31 is attached to the intake structure 20 in at least part. Specifically, the first protective cover 31 is fixed to a tab 22c protruding from the outer circumferential surface of the downstream portion 22a of the first intake duct 22, a tab 22d protruding from the outer circumferential surface of the upstream portion 22b of the first intake duct 22, and a tab portion 24d protruding from the outer circumferential surface of the second intake duct 24. Specifically, as shown in Figure 8A, the first protective cover 31 has fastening holes 31d that coincide with the fastening holes 24f of the tab portion 24d. The fasteners 27 are, for example, rivets, but may also be bolts. The fasteners 27 fix the first protective cover 31 to the first intake duct 22 by inserting them through the fastening holes 31d of the first protective cover 31 and the fastening holes 24f of the first intake duct 22. The first protective cover 31 may also be further fixed to the vehicle body frame 2 by fasteners.

[0048] The second protective cover 32 covers the lid 52 and lock 54 of the air cleaner 23 from the rear of the vehicle. The second protective cover 32 is not located in front of the lid 52 of the air cleaner 23 in the longitudinal direction of the vehicle. That is, the second protective cover 32 does not cover the lid 52 from the front of the vehicle. The second protective cover 32 is detachably engaged with the air cleaner 23 by a tool-free engaging structure 72. Specifically, as shown in Figure 8B, the engaging structure 72 includes a boss portion 41a protruding from the air cleaner case 41 of the air cleaner 23 and an elastic ring 73 fitted into a hole 32a of the second protective cover 32. The elastic ring 73 is, for example, a rubber ring.

[0049] The outer circumferential surface of the boss portion 41a is provided with a retaining portion 41b that protrudes radially outward from the boss portion 41a. The second protective cover 32 engages with the air cleaner case 41 when the boss portion 41a inserts the elastic ring 73 so that the retaining portion 41b passes through the central hole of the elastic ring 73. This allows the worker to remove the second protective cover 32 by hand without using tools. Therefore, when replacing the air cleaner element 42, the lid 52 can be opened by removing the second protective cover 32 by hand and then releasing the lock 54 by hand. Note that the engagement structure 72 is not limited to the boss elastic press-fit structure shown in Figure 8B, but may be, for example, a claw locking structure.

[0050] The third protective cover 33 covers the resin inlet cover portion 25b of the supercharger 25. Since the inlet cover portion 25b of the supercharger 25 is located on the outside in the vehicle width direction of the housing portion 25a, it is covered by the third protective cover 33 from the outside in the vehicle width direction. The third protective cover 33 is detachably fixed to the supercharger 25 by fasteners.

[0051] Furthermore, if an intake duct and an exhaust duct are connected to a continuously variable transmission (CVT) to cool the CVT that changes the driving force output by the internal combustion engine 12, and at least one of the intake duct and exhaust duct directly faces the rear wheel 4, then at least one of the intake duct and exhaust duct for the CVT may be partially covered by at least one protective cover. That is, the portion of at least one of the intake duct and exhaust duct for the CVT that faces the rear wheel 4 may be covered by at least one protective cover. In addition, although this embodiment illustrates a structure in which the intake structure 20 is covered by three protective covers 31 to 33, at least two of the protective covers 31 to 33 may be integrated as a one-piece unit.

[0052] With the configuration described above, the intake air flowing into the dirty area S1 from the inlet 61e of the air cleaner case 41 spreads evenly along the outer surface of the air filter 42b, allowing the intake air to pass through the air filter 42b relatively uniformly and smoothly. Therefore, the performance of the off-road vehicle 1 can be improved in terms of intake air.

[0053] Figure 9 is a longitudinal cross-sectional view of a modified air cleaner 123. Components common to the previously described embodiment are denoted by the same reference numerals and their descriptions are omitted. As shown in Figure 9, the case body 151 of the air cleaner case 141 of the modified air cleaner 123 includes an inlet cylinder 162 with a different shape from the inlet cylinder 62 of the previously described embodiment. The inlet cylinder 162 includes an elongated cylindrical portion 162a, a true cylindrical portion 162b, and a transition portion 162c. The elongated cylindrical portion 162a of the inlet cylinder 162 is the downstream end of the inlet cylinder 162 and has the same oval cross-section as the inlet 61e of the case portion 61. The true cylindrical portion 162b is the upstream end of the inlet cylinder 162 and has a true circular cross-section. The downstream end of the first intake duct 122 connected to the inlet cylinder 162 has a true circular cross-section. The transition section 162c has a cross-section that smoothly changes from a circular shape to an oblong shape from the upstream side to the downstream side, so as to smoothly connect the cylindrical section 162b to the elongated cylindrical section 162a.

[0054] Even with this configuration, the intake air that flows from the first intake duct 122 into the inlet cylinder 162 flows into the dirty region S1 from the inlet 61e of the case 61 and spreads evenly along the outer surface of the air filter 42b, so that the intake air can pass through the air filter 42b relatively uniformly and smoothly.

[0055] As described above, the embodiments have been explained as examples of the technology disclosed in this application. However, the technology in this disclosure is not limited to these embodiments and can be applied to embodiments that have been modified, replaced, added, or omitted as appropriate. It is also possible to combine the components described in the embodiments to create new embodiments. For example, some components or methods in one embodiment may be applied to other embodiments, and some components in an embodiment can be separated from other components in that embodiment and extracted as appropriate. Furthermore, the components described in the attached drawings and detailed description include not only components essential for solving the problem, but also components that are not essential for solving the problem, in order to illustrate the technology.

[0056] [Aspect] The embodiments described above are specific examples of the following embodiments.

[0057] (Aspect 1) An intake duct that defines the dirty airflow path, The system includes an air cleaner connected to the aforementioned intake duct, The aforementioned air cleaner is, An air cleaner case that defines the internal space, The air cleaner element, housed in the air cleaner case, includes an air filter that divides the internal space into a dirty area and a clean area, The aforementioned air cleaner case is The inner surface that defines the aforementioned internal space, An inlet is provided on the inner surface and faces the air filter via the dirty region, Includes an outlet facing the clean area, The air filter extends in a predetermined direction, The inlet has a shape that extends in the predetermined direction, and is an off-road vehicle.

[0058] With this configuration, the intake air that flows into the dirty area from the inlet of the air cleaner case spreads widely across the surface of the air filter, allowing the intake air to pass through the air filter relatively uniformly and smoothly. Therefore, the vehicle's performance in terms of intake can be improved.

[0059] (Aspect 2) The aforementioned air filter has a cylindrical shape, The predetermined direction is the axial direction of the air filter. The inner surface of the air cleaner case is an inner surface that faces the outer surface of the air filter. The clean area is defined on the inner circumferential surface of the air filter. The off-road vehicle according to embodiment 1, wherein the dirty area is defined between the inner circumferential surface of the air cleaner case and the outer circumferential surface of the air filter.

[0060] This configuration allows for a compact air cleaner with a large surface area, while still enabling even distribution of intake air that enters the dirty area from the inlet of the air cleaner case along the outer surface of the air filter.

[0061] (Aspect 3) The off-road vehicle according to embodiment 2, wherein the axial direction is a direction that is oriented at an angle within the range of less than 45° with respect to the vertical line when viewed from the horizontal direction.

[0062] This configuration allows the air cleaner to have a vertically extending shape, reducing the horizontal space it occupies within the vehicle.

[0063] (Aspect 4) The aforementioned air cleaner case is A case body having the inlet, the outlet located on one side in the axial direction, and a maintenance opening located on the other side in the axial direction, An off-road vehicle according to embodiment 2 or 3, comprising a lid for closing the maintenance opening of the case body.

[0064] With this configuration, the air cleaner element can be replaced by opening the lid and accessing the maintenance opening in the case. Furthermore, since the inlet and outlet are located on the case body rather than the lid, interference between the intake duct and the lid can be prevented when replacing the air cleaner element.

[0065] (Aspect 5) The off-road vehicle according to any one of embodiments 1 to 4, wherein the inlet has a larger area than the outlet.

[0066] This configuration allows for smoother airflow from the air cleaner case inlet into the dirty area.

[0067] (Aspect 6) The aforementioned air cleaner case is The case portion having the aforementioned inner surface, It includes an inlet cylindrical portion that protrudes outward from the case portion, to which the intake duct is connected, and which defines a flow path that communicates with the inlet, The inlet cylinder portion has a shape that extends in the predetermined direction when viewed from the direction of the flow path axis of the inlet cylinder portion, The intake duct has a downstream portion connected to the inlet cylindrical portion, The off-road vehicle according to any one of embodiments 1 to 5, wherein the downstream portion of the intake duct has a shape that extends in the predetermined direction when viewed from the direction of the flow path axis of the outlet of the downstream portion.

[0068] This configuration allows for smoother intake airflow from the intake duct to the air cleaner.

[0069] (Aspect 7) The intake duct has an upstream portion located on the upstream side of the downstream portion in the intake air flow direction of the intake duct, The off-road vehicle according to embodiment 6, wherein the outlet of the downstream portion of the intake duct is larger than the inlet of the upstream portion of the intake duct.

[0070] With this configuration, the cross-sectional shape of the intake duct changes as it moves from the upstream side to the downstream side, allowing the intake air to be diffused over a wider area as it approaches the air filter.

[0071] (Pattern 8) The intake duct is the first intake duct, The vehicle further comprises a second intake duct connected to the air cleaner and defining a clean airflow path, The off-road vehicle according to embodiment 7, wherein the minimum flow path cross-sectional area of ​​the upstream portion of the first intake duct is larger than the minimum flow path cross-sectional area of ​​the second intake duct.

[0072] This configuration allows for a smoother flow of intake air from the first intake duct into the air cleaner.

[0073] (Aspect 9) An off-road vehicle according to any one of embodiments 1 to 8, wherein the size of the inlet in the predetermined direction is greater than half the size of the air filter in the predetermined direction.

[0074] This configuration allows intake air that flows into the dirty area from the inlet of the air cleaner case to be spread over a wide area across the surface of the air filter.

[0075] (Aspect 10) The intake duct is the first intake duct, The aforementioned vehicle is A second intake duct connected to the aforementioned air cleaner and defining a clean airflow path, It includes at least one protective cover, and furthermore, The first intake duct, the air cleaner, and the second intake duct constitute an intake structure. The off-road vehicle according to any one of embodiments 1 to 9, wherein the at least one protective cover partially covers the intake structure.

[0076] With this configuration, the protective cover prevents damage to the intake structure caused by something hitting it.

[0077] (Aspect 11) Equipped with wheels, The off-road vehicle according to embodiment 10, wherein the at least one protective cover is positioned between the wheel and the intake structure.

[0078] This configuration protects the air intake structure from stones and other debris kicked up by the wheels.

[0079] (Aspect 12) The off-road vehicle according to embodiment 10 or 11, wherein at least one of the protective covers is attached to the intake structure in part.

[0080] This configuration allows the protective cover to adequately cover the intake structure while preventing the protective cover from becoming too large.

[0081] (Aspect 13) The aforementioned at least one protective cover includes a one-piece protective cover, The off-road vehicle according to any one of embodiments 10 to 12, wherein the one-piece protective cover covers at least two of the group consisting of the first intake duct, the air cleaner, and the second intake duct.

[0082] This configuration allows for extensive protection of the intake structure by a one-piece protective cover.

[0083] (Aspect 14) The off-road vehicle according to any one of embodiments 10 to 13, wherein the at least one protective cover has a shape that conforms to the outer shape of the intake structure.

[0084] This configuration allows for a smaller overall gap between the protective cover and the intake structure, thereby effectively protecting the intake structure.

[0085] (Aspect 15) The off-road vehicle according to any one of embodiments 10 to 14, wherein the at least one protective cover includes a protective cover that is detachably engaged with the intake structure by a tool-free engagement structure.

[0086] This configuration allows the protective cover to be removed without tools, thus maintaining good maintainability of the intake structure.

[0087] (Aspect 16) The aforementioned at least one protective cover includes a first protective cover and a second protective cover, The first protective cover is fixed to the intake structure by fasteners that are attached and detached by a tool. The off-road vehicle according to any one of embodiments 10 to 15, wherein the second protective cover is detachably engaged with the intake structure by a tool-free engagement structure.

[0088] With this configuration, the first protective cover is firmly fixed to the intake structure, while the second protective cover can be removed without tools, thus maintaining good maintainability of the air cleaner.

[0089] (Aspect 17) The air cleaner case includes a case body having a maintenance opening, a lid that closes the maintenance opening of the case body, and a lock that locks the lid to the case body when the lid is closed. The off-road vehicle according to embodiment 16, wherein the second protective cover covers at least one of the lid and the lock.

[0090] This configuration allows for easy removal of the second protective cover and unlocking of the lid, thus maintaining good maintainability of the air cleaner.

[0091] (Aspect 18) An intake duct that defines the dirty airflow path, The system includes an air cleaner connected to the aforementioned intake duct, The aforementioned air cleaner is, An air cleaner case that defines the internal space, The air cleaner element, housed in the air cleaner case, includes an air filter that divides the internal space into a dirty area and a clean area, The aforementioned air cleaner case is The inner surface that defines the aforementioned internal space, An inlet is provided on the inner surface and faces the air filter via the dirty region, Includes an outlet facing the clean area, The air filter extends in a predetermined direction, An off-road vehicle in which the size of the inlet in the predetermined direction is greater than half the size of the air filter in the predetermined direction.

[0092] With this configuration, intake air that flows into the dirty area from the inlet of the air cleaner case spreads widely across the surface of the air filter, allowing the intake air to pass through the air filter uniformly and smoothly. Therefore, the vehicle's performance in terms of intake air can be improved.

[0093] (Aspect 19) Ducts and, Air cleaner and, An off-road vehicle comprising at least one protective cover that partially covers the duct or the air cleaner.

[0094] With this configuration, a protective cover can prevent damage to the duct or air cleaner caused by stones or other objects kicked up by the wheels hitting them. [Explanation of Symbols]

[0095] 1. Off-road vehicle 2. Vehicle frame 4 Rear wheels 12 Internal Combustion Engines 20 Intake structure 22 First intake duct 22a downstream 22b Upstream part 23 Air Cleaner 24 Second intake duct 24a Part 1 24b Part 2 24c Part 3 25 Supercharger 27 Fasteners 31. First protective cover 32. Second protective cover 33. Third protective cover 41 Air cleaner case 42 Air cleaner element 42b Air filter 51 Case body 52 Lid 54 Rock 61d Inner surface 61e Inlet 61 Case section 61c Maintenance opening 62 Inlet cylinder part 63a Outlet 72 Engagement structure C Cabin S interior space S1 Dirty Area S2 Clean Area V vertical line X-axis direction Y-direction of the flow path axis

Claims

1. An intake duct that defines the dirty airflow path, The system includes an air cleaner connected to the aforementioned intake duct, The aforementioned air cleaner is, An air cleaner case that defines the internal space, The air cleaner element, housed in the air cleaner case, includes an air filter that divides the internal space into a dirty area and a clean area, The aforementioned air cleaner case is The inner surface that defines the aforementioned internal space, An inlet is provided on the inner surface and faces the air filter via the dirty region, Includes an outlet facing the clean area, The air filter extends in a predetermined direction, The inlet has a shape that extends in the predetermined direction, and is an off-road vehicle.

2. The aforementioned air filter has a cylindrical shape, The predetermined direction is the axial direction of the air filter. The inner surface of the air cleaner case is an inner surface that faces the outer surface of the air filter. The clean area is defined on the inner circumferential surface of the air filter. The off-road vehicle according to claim 1, wherein the dirty area is defined between the inner circumferential surface of the air cleaner case and the outer circumferential surface of the air filter.

3. The off-road vehicle according to claim 2, wherein the axial direction is a direction that is oriented at an angle of less than 45° with respect to the vertical line when viewed from the horizontal direction.

4. The aforementioned air cleaner case is A case body having the inlet, the outlet located on one side in the axial direction, and a maintenance opening located on the other side in the axial direction, The off-road vehicle according to claim 2, further comprising a lid for closing the maintenance opening of the case body.

5. The off-road vehicle according to claim 1, wherein the inlet has a larger area than the outlet.

6. The aforementioned air cleaner case is The case portion having the aforementioned inner surface, It includes an inlet cylindrical portion that protrudes outward from the case portion, to which the intake duct is connected, and which defines a flow path that communicates with the inlet, The inlet cylinder portion has a shape that extends in the predetermined direction when viewed from the direction of the flow path axis of the inlet cylinder portion, The intake duct has a downstream portion connected to the inlet cylindrical portion, The off-road vehicle according to claim 1, wherein the downstream portion of the intake duct has a shape that extends in the predetermined direction when viewed from the direction of the flow path axis of the outlet of the downstream portion.

7. The intake duct has an upstream portion located on the upstream side of the downstream portion in the intake air flow direction of the intake duct, The off-road vehicle according to claim 6, wherein the outlet of the downstream portion of the intake duct is larger than the inlet of the upstream portion of the intake duct.

8. The intake duct is the first intake duct, The vehicle further comprises a second intake duct connected to the air cleaner and defining a clean airflow path, The off-road vehicle according to claim 7, wherein the minimum flow path cross-sectional area of ​​the upstream portion of the first intake duct is greater than the minimum flow path cross-sectional area of ​​the second intake duct.

9. The off-road vehicle according to claim 1, wherein the size of the inlet in the predetermined direction is greater than half the size of the air filter in the predetermined direction.

10. The intake duct is the first intake duct, The aforementioned vehicle is A second intake duct connected to the aforementioned air cleaner and defining a clean airflow path, It further includes at least one protective cover, The first intake duct, the air cleaner, and the second intake duct constitute an intake structure. The off-road vehicle according to claim 1, wherein the at least one protective cover partially covers the intake structure.

11. Equipped with wheels, The off-road vehicle according to claim 10, wherein the at least one protective cover is positioned between the wheel and the intake structure.

12. The off-road vehicle according to claim 10, wherein at least one of the protective covers is attached to the intake structure in part.

13. The aforementioned at least one protective cover includes a one-piece protective cover, The off-road vehicle according to claim 10, wherein the one-piece protective cover covers at least two of the group consisting of the first intake duct, the air cleaner, and the second intake duct.

14. The off-road vehicle according to claim 10, wherein the at least one protective cover has a shape that conforms to the outer shape of the intake structure.

15. The off-road vehicle according to claim 10, wherein the at least one protective cover includes a protective cover that is detachably engaged with the intake structure by a tool-free engagement structure.

16. The aforementioned at least one protective cover includes a first protective cover and a second protective cover. The first protective cover is fixed to the intake structure by fasteners that can be attached and detached with a tool. The off-road vehicle according to claim 10, wherein the second protective cover is detachably engaged with the intake structure by a tool-free engagement structure.

17. The air cleaner case includes a case body having a maintenance opening, a lid that closes the maintenance opening of the case body, and a lock that locks the lid to the case body when the lid is closed. The off-road vehicle according to claim 16, wherein the second protective cover covers at least one of the lid and the lock.

18. An intake duct that defines the dirty airflow path, The system includes an air cleaner connected to the aforementioned intake duct, The aforementioned air cleaner is, An air cleaner case that defines the internal space, The air cleaner element, housed in the air cleaner case, includes an air filter that divides the internal space into a dirty area and a clean area, The aforementioned air cleaner case is The inner surface that defines the aforementioned internal space, An inlet is provided on the inner surface and faces the air filter via the dirty region, Includes an outlet facing the clean area, The air filter extends in a predetermined direction, An off-road vehicle in which the size of the inlet in the predetermined direction is greater than half the size of the air filter in the predetermined direction.

19. Ducts and, Air cleaner and, An off-road vehicle comprising at least one protective cover that partially covers the duct or the air cleaner.

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