vehicle

Abstract

Vehicle (1), comprising: a body frame (2); and an internal combustion engine (9) attached to the body frame (2), wherein the internal combustion engine (9) comprises a crankcase (51) with a top wall (51b), a cylinder (52) located in a front end region of a top of the crankcase (51), a ventilation chamber (67) on the top of the crankcase (51), a crankshaft (63) provided in the crankcase (51) and rotatably mounted, and a balancing mechanism (66) located in the crankcase (51) configured to reduce the vibration of the internal combustion engine (9) by force transmitted by the crankshaft (63); wherein the compensating mechanism (66) comprises an idle gear (83) behind the crankshaft (63), rotated by the force transmitted by the crankshaft (63), and a compensator (85) behind the idle gear (83), rotated by the force transmitted by the idle gear (83); wherein the idle gear (83) and the compensator (85) are arranged along the ceiling wall (51b), wherein the compensator (85) is arranged such that the rotational centerline of the compensator (85) lies below an imaginary line segment (La) which connects the rotational centerline of the idle gear (83) and the rotational centerline of the crankshaft (63), and wherein the ventilation chamber (67) is located behind the cylinder and covers at least part of the compensator (85) in a side view of the internal combustion engine (9), further comprising an anti-lock braking system (18) which is mounted on the body frame (2), covers at least part of the compensator (85) in a top view of the body frame (2), and covers at least part of the ventilation chamber (67) in a side view of the body frame (2).

Description

Field of the invention

[0001] The present invention relates to a vehicle. Description of the state of the art

[0002] A combustion engine is generally known which is equipped with a crankshaft and two compensating elements which enclose the crankshaft between them, e.g. DE 601 31 584 T2.

[0003] This internal combustion engine rotates the two balance elements in opposite directions. Thus, the crankshaft torque is transmitted directly to one of the two balance elements, and the torque reversed by the idle gear is transmitted to the other balance element (e.g., JP 2007-78080 A).

[0004] From DE 41 34 399 A1 a vehicle is known with a balancing device in which two balancing weights are arranged at the same height on both sides of the crankshaft, of which one balancing weight is driven directly by a gear located coaxially with the crankshaft, while the other balancing weight is driven via the idle gear located below the ceiling wall of the crankcase.

[0005] JP 2002-181 134 A shows a vehicle whose engine is equipped with a balancer mechanism. The center of the balance weight lies below the line connecting the crankshaft to the rotational centerline of an idle gear.

[0006] The idle gear and the compensating element rotated with it of the conventional internal combustion engine are arranged along the cylinder and are also arranged in the direction in which the center line of the cylinder bore runs.

[0007] This arrangement of the idler gear and the compensating element reduces the available space behind the cylinder and above the ball housing. In the case of a motorcycle, for example, such a reduction in available space prevents an increase in the fuel tank capacity and prevents the provision of mounting space for equipment such as an anti-lock braking system. DISCLOSURE OF THE INVENTION

[0008] To solve the problems discussed above, it is an object of the present invention to provide a vehicle that includes a counterbalance mechanism for reducing vibration of the internal combustion engine and leaves room to increase the size of the fuel tank and / or to dispose a device or components behind the cylinder and above the crankcase.

[0009] To achieve the above object, one aspect of the invention provides a vehicle incorporating the features of claim 1.

[0010] According to the invention, it is possible to provide a vehicle which includes a compensation mechanism for reducing the vibration of the internal combustion engine and leaves available space for increasing the fuel tank size and / or leaves space for arranging devices or components behind the cylinder and above the crankcase BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a left side view illustrating a vehicle according to an embodiment of the invention. Fig. 2 is a left side view of an internal combustion engine according to the embodiment of the invention. Fig. 3 is a plan view of the internal combustion engine according to the embodiment of the invention. Fig. 4 is a partial left side view of the vehicle according to the embodiment of the invention. Fig. 5 is a partial plan view of the vehicle according to the embodiment of the invention. Fig. 6 is a schematic diagram of a lubrication system of the internal combustion engine according to the embodiment of the invention. Fig. 7 is a partial perspective view of the lubrication system of the internal combustion engine according to the embodiment of the invention. Fig. 8 is a partial cross-sectional view of the lubrication system of the internal combustion engine according to the embodiment of the invention. DETAILED DESCRIPTION

[0011] In the following, an embodiment of a vehicle according to the invention is described with reference to Fig. 1 to 8. In each figure, like reference numerals refer to identical or equivalent components.

[0012] Fig. 1 is a left side view showing the vehicle according to the embodiment of the invention.

[0013] In the present embodiment, directional information such as front, rear, top, up, down, down, right, and left are relative to a driver (operator or chauffeur) of the vehicle. The same applies to an internal combustion engine, and the directional information for the internal combustion engine refers to the engine's installation state.

[0014] As in Fig. 1, the vehicle according to the invention is, for example, a ride-on vehicle, here a motorcycle 1. The motorcycle 1 according to the embodiment includes a body frame 2 extending in the front-rear direction of the motorcycle 1 (that is, in the vehicle longitudinal direction), a front wheel 5 is provided in front of the body frame 2, a steering mechanism 6 rotatably supporting the front wheel 5 is provided at the front end portion of the body frame 2, a rear wheel 7 is provided behind the body frame 2, and a swing arm 8 rotatably supporting the rear wheel 7 is provided at the rear portion of the body frame 2, and an internal combustion engine 9 (hereinafter referred to simply as engine 9) is mounted on the body frame 2.

[0015] The motorcycle 1 further includes an intake system 11 for cleaning intake air (i.e., air sucked into the engine 9) and for supplying an air-fuel mixture with a required flow rate to the engine 9, a fuel tank 12 for containing fuel to be supplied to the engine 9, a saddle 13 on which the rider sits, and a fairing 15 covering at least part of the body frame 2.

[0016] The motorcycle 1 further includes a front wheel brake 16 for braking the rotating front wheel 5, a rear wheel brake 17 for braking the rotating rear wheel 7, and an anti-lock brake system 18 for preventing the front wheel brake 16 and the rear wheel brake 17 from locking during braking.

[0017] The body frame 2, for example, is a so-called cradle frame. The body frame 2 includes a steering head tube 21 at the front end of the body frame 2, a pair of right and left main frames 22 that branch to the right and left immediately behind the steering head tube 21 and then extend rearward, and a pair of right and left seat rails 23 that are connected to the rear end of the main frames and gradually extend rearward.

[0018] The steering head tube 21 controllably supports the steering mechanism 6. The steering head tube 21 is the center of rotation of the steering mechanism 6 and supports the steering mechanism 6 on the body frame 2.

[0019] The right and left main frames 22 are curved, that is, each main frame 22 includes an elongated stretched section branching off immediately behind the steering head tube 21 to increase the distance between the right and left main frames 22 to approximately the same lateral width as the engine and gradually extending downwards in the rearward direction of the motorcycle 1. A short straight section connected to the elongated stretched section extends downwards. The right and left main frames 22 support the engine 9, which is located below the elongated stretched sections and in front of the short straight sections to support the engine 9.The right and left main frames 22 support the air cleaner 25 located above the front half of the elongated sections, support the fuel tank 12 above the rear half of the elongated sections, and support a pivot shaft 26 extending in the vehicle width direction between the short elongated sections. The pivot shaft 26 pivotally supports the swing arm 8.

[0020] The engine 9 is located behind the front wheel 5 and below the main frame 22, it occupies the middle and lower area of ​​the motorcycle 1. The engine 9 contains several, for example four cylinder bores (i.e. cylinders, Fig. 3), which are arranged in the vehicle width direction of the motorcycle 1. That is, the engine 9 is a multi-cylinder in-line engine, for example, a four-cylinder in-line engine.

[0021] The intake system 11 of the engine 9 includes the air cleaner 25 for cleaning the air sucked into the engine 9, a throttle body 27 for injecting fuel into the cleaned air after it has passed through the air cleaner 25 to form an air-fuel mixture, and for changing the flow rate of the intake air (mixture) supplied to the engine 9.

[0022] The air filter 25 is located above the front half of the body frame 2. The air filter 25 is connected to the intake side of the engine 9 via the throttle body 27. The air filter 25 filters and cleans the intake air. The air filter 25 is enclosed between the right and left main frames 22.

[0023] The throttle body 27 is located between the air cleaner 25 and the engine 9. In the intake air flow supplied to the engine 9, the air cleaner 25 is connected to the upstream side of the throttle body 27, and the engine 9 is connected to the downstream side of the throttle body 27.

[0024] The fuel tank 12 is located above the front half of the body frame 2 and behind the air filter 25.

[0025] The steering mechanism 6 includes a steering shaft (not shown) passing through the steering head tube 21 and serving as a center of rotation for the steering mechanism 6, a front fork 28 consisting of right and left parts in vertical extension, and handlebars 29 connected to the upper ends of the two parts of the front fork 28 and extending to the right and left of the motorcycle 1.

[0026] The handlebars 29 are equipped with handgrips 31 for the rider to grip. The right handgrip 31 is a throttle grip. Turning the handle changes the opening of the throttle body 27 (more precisely, a throttle valve) according to the rotational amount, thus changing the output power of the engine 9.

[0027] The front end portion of the swing arm 8 is pivotally connected to the body frame 2 via the pivot shaft 26. The rear end portion of the swing arm 8 rotatably supports the rear wheel 7. A rear damping unit 33 bridges the area between the swing arm 8 and the body frame 2. The rear damping unit 33 buffers the force transmitted from the rear wheel 7 to the body frame 2.

[0028] The rear wheel 7 contains a driven sprocket 35. The drive chain 36 is wrapped around the driven sprocket 35 and transmits torque from the motor 9 to the rear wheel 7.

[0029] The saddle 13 is located above the rear half of the body frame 2.

[0030] The fairing 15 covers the body frame 2 and conceals it, for example, from the front area down to the center lower area of ​​the vehicle body. The fairing 15 has a streamlined shape, whereby the fairing 15 reduces air resistance when riding the motorcycle 1 and protects the rider from wind pressure. The fairing 15 includes a front cover 41 for covering the front part of the motorcycle 1, a pair of right and left side covers 42 for covering the side of the engine 9, an air cleaner cover 43 for covering the air cleaner 25 and the fuel tank 12, and a rear cover 45 for supporting the seat 13 and covering the rear part of the motorcycle 1.

[0031] The front brake 16 applies braking force to the front wheel 5 when a front brake lever (not shown) located on the right handlebar 31 is pulled. The front brake 16 releases the braking force on the front wheel 5 when the operation of the front brake lever is released (or canceled).

[0032] The rear brake 17 applies braking force to the rear wheel 7 when a rear brake lever (not shown) on the right footrest (not shown) is depressed. The rear brake 17 releases the braking force on the rear wheel 7 when the rear brake lever is released.

[0033] The anti-lock brake system 18 is located in the space between the fuel tank 12 and the engine 9. The anti-lock brake system (hereinafter: anti-lock brake system) 18 adjusts the braking force according to the running state of the engine 1. For example, the anti-lock brake system 18 detects the difference between the vehicle speed and the rotational speed of the rear wheel 7 or the front wheel 5. When this difference increases and slippage is expected to occur, the anti-lock brake system 18 reduces the braking force of the front wheel brake 16 and the braking force of the rear wheel brake 17 to prevent slipping.

[0034] Next, the motor 9 of this embodiment will be described in detail.

[0035] Fig. 2 is a left side view of the internal combustion engine according to the embodiment of the invention.

[0036] As in Fig. 2, the engine 9 of the embodiment of the invention includes a crankcase 51, a cylinder 52, a cylinder head 53, a head cover 55, and an oil pan 56.

[0037] A transmission housing is integrated with the crankcase 51. A crank chamber 61 is partitioned in the front half of the crankcase 51, and a transmission chamber 62 is partitioned in the rear half of the crankcase 51. The crank chamber 61 rotatably accommodates the crankshaft 63, and the transmission chamber 62 accommodates a gear 65. The crank chamber 61 and the transmission chamber 62 are opposite each other in the forward-reverse direction of the engine 9. The crank chamber 61 and the transmission chamber 62 are adjacent to each other such that a compartment within the crankcase 51 is located between the two chambers 61 and 62.

[0038] A balancing mechanism 66 is located in the crankcase 51. The balancing mechanism 66 reduces the periodic torsional vibration of the crankshaft 63 due to the force transmitted from the crankshaft 63.

[0039] A vent chamber 67 is located in the crankcase 51, it is located at the top of the crankcase 51 and behind the cylinder 52. The vent chamber 67 separates the oil contained in the blowby gas within the crankcase 51.

[0040] The crankcase 51 includes an upper case 68 in its upper half and a lower case 69 in its lower half. The upper case 68 and the lower case 69 serve together to partition the crank chamber 61 and the transmission chamber 62. The upper case 68 and the lower case 69 are joined together at a mating surface 51a. The rotational centerline of the crankshaft 63, the rotational centerline of the input shaft 71 (i.e., the countershaft 71) of the transmission 65, and the rotational centerline of the output shaft 72 (i.e., the drive shaft 72) of the transmission 65 lie on an imaginary (i.e., virtual) plane passing through the mating surface 51a. The cylinder 52 and the upper case 68 may form an integrated cylinder block.

[0041] The cylinder 52 is located at the front end portion of the top of the crankcase 51. The cylinder 52 is slightly inclined forward from the upright state. In other words, the cylinder 52 is inclined such that its upper portion (the side with the head cover 55) is located more toward the front than its bottom side (i.e., the side of the crankcase 51). The cylinder 52 includes a plurality of cylinder bores 73 arranged in a row in the width direction of the engine 9. All of the cylinder bores 73 are arranged so that the centerline of each cylinder bore 73 lies substantially on the same imaginary plane. A piston 74 is located in each cylinder bore 73. The pistons 74 are accommodated in the corresponding cylinder bores 73 so that they can reciprocate toward and away from the crankshaft 73 (i.e., in the radial direction of the crankshaft 63).The center line of each cylinder bore 73, which is the reciprocating direction of each piston 74, is inclined slightly forward, similar to the cylinder 52.

[0042] The cylinder head 53 closes the upper regions of the cylinder bores 73 and divides combustion chambers (not shown) between the cylinder head 53 and the piston 74. The engine 9 causes the crank 74 to reciprocate by periodically burning the air-fuel mixture in the corresponding combustion chambers.

[0043] The crankshaft 63 is supported between the upper case 68 and the lower case 69 at the mating surface 51a in such a way that it is rotatably supported. The crankshaft 63 extends in the width direction of the engine 9. In other words, the rotational centerline of the crankshaft 63 extends in the width direction of the engine 9. The crankshaft 63 is located at or near the intersection of the mating surface 51a and the extension line of the centerlines of the cylinder bores 63. The crankshaft 63 is connected to each piston 74 via a connecting rod. The crankshaft 63 converts the reciprocating motion of this piston 74 into rotary motion.

[0044] The transmission 65 converts the rotational speed of the crankshaft 63 on its input side depending on the selected gear ratio and rotates its output shaft at the converted rotational speed. The transmission 65 is a so-called manual dog clutch transmission. The transmission 65 includes the countershaft 71 on the input side connected to the crankshaft 63, the drive shaft 72 on the output side, gear wheels 65 for changing the rotational speed and for transmitting the changed rotational speed from the countershaft 71 to the drive shaft 72, and a shifting mechanism (not shown).

[0045] The countershaft 71 and the drive shaft 72 extend parallel to the crankshaft 63. That is, the countershaft 71 and the drive shaft 72 extend in the width direction of the engine 9. In other words, the rotational centerline of the countershaft 71 and that of the drive shaft 72 are arranged parallel to the rotational centerline of the crankshaft 63. The rotational centerline of the countershaft 71 and that of the drive shaft 72 extend in the width direction of the engine 9.

[0046] The rotational centerline of the countershaft 71 passes through the mating surface 51a, and the countershaft 71 transmits torque between the crankshaft 63 and the input shaft 72. At one of the end portions of the countershaft 71, for example, the right end portion, a clutch mechanism (not shown) is provided. The clutch mechanism integrally and rotatably supports an unillustrated primary driven gear. The primary driven gear meshes with an unillustrated primary drive gear, which is integrally and rotatably provided on the crankshaft 63. The clutch mechanism integrally drives the primary driven gear with respect to the countershaft 71 to transmit torque between the crankshaft 63 and the countershaft 71 or to interrupt (i.e., cancel) the power transmission between the two parts.

[0047] The drive shaft 72 is located behind the countershaft 71. That is, the drive shaft 72 is located farther away from the crankshaft 63 than the countershaft 71. The other of the end portions, for example, the left end portion of the drive shaft 72, protrudes from the left side wall of the lower housing 69 to the outside of the transmission chamber 62. A drive sprocket (not shown) is attached to the end portion of the drive shaft 72 located outside the transmission chamber 62. The drive chain 36 is wound around the drive sprocket to transmit torque to the rear wheel 7 via the drive chain 36.

[0048] The transmission gears 75 contain several gear pairs 78. Each gear pair 78 consists of a countershaft gear 79 supported by the countershaft 71 and a drive gear 81 located on the input shaft 72, which continuously meshes with the countershaft gear 79. Each gear pair 78 has a transmission ratio different from the other gear pairs 78, for example, from the first-gear gear pair 78a to the sixth-gear gear pair 78f.

[0049] The shifting mechanism includes shift dogs attached to the gear pairs 78 of the transmission gears 75. The shifting mechanism alternately selects a gear pair 78 that changes the speed transmitted (i.e., input) from the countershaft 71, and then transmits (i.e., outputs) the changed speed to the input shaft 72 via the dog clutch. The gear ratio is determined by which gear pair 78 is selected, and the selected gear pair 78 transmits the speed (i.e., power or torque) from the countershaft 71 to the input shaft 72 according to its gear ratio. All other transmission gear pairs 78 rotate the input gear 81 or the countershaft gear 79 in neutral mode and do not transmit any torque (i.e., they lock the power transmission).

[0050] The balancer mechanism 66 is a so-called biaxial secondary balancer. The balancer mechanism 66 includes a pair of balancers 85 and 86 (two axes) configured to rotate at twice the speed of the crankshaft 63 to reduce the secondary vibration caused by the rotation of the crankshaft 63.

[0051] The balancer mechanism 66 includes an idler or intermediate gear pair 83 behind the crankshaft 63, it is rotated by the power transmitted from the crankshaft 63, the mechanism further includes a first balancer 85 behind the intermediate gear 83, rotated by the power from the intermediate gear 83, and a second balancer 86 in front of the crankshaft 63, rotated by the power from the crankshaft 63.

[0052] In other words, the paired balancers 85 and 86 are located in front of and behind the crankshaft 63, with the crankshaft 63 in between. The second balancer 86 is located in front of the crankshaft 63 and rotates at twice the speed of the crankshaft 63 in the direction opposite to the direction of rotation of the crankshaft 63. The first balancer 85, located behind the crankshaft 63, rotates at twice the speed of the crankshaft 63 in the same direction as the crankshaft 63 itself.

[0053] The first balancer 85 and the second balancer 86 extend parallel to the crankshaft 63. That is, the first balancer 85 and the second balancer 86 extend in the width direction of the engine 9. In other words, those components are arranged such that the respective rotational centerlines of the intermediate gear 83, the first balancer 85, and the second balancer 86 extend parallel to the rotational centerline of the crankshaft 63. The respective rotational centerlines of the intermediate gear 83, the first balancer 85, and the second balancer 86 extend in the width direction of the engine 9.

[0054] The first balancer 85 is located at a position farther from the cylinder bores 73 than the intermediate gear 83. The rotational centerline of the first balancer 85 is located at a position farther from the cylinder bores 73 than the rotational centerline of the intermediate gear 83. The rotational centerline of the first balancer 85 is located at a position farther from the cylinder bores 73 than the intermediate gear 83. In other words, the intermediate gear 83 and the first balancer 85 are sequentially arranged in the direction crossing the centerlines of the cylinder bores 73, that is, in the direction away from the cylinder bores 73 in a side view of the engine 9.

[0055] The intermediate gear 83 and the first balancer 85 are arranged along the ceiling wall 51b of the crankcase 51. That is, the intermediate gear 83 and the first balancer 85 are adjacent to the ceiling wall 51b of the crankcase 51.

[0056] The first balancer 85 is arranged such that the rotational centerline of the first balancer 85 is located below the imaginary line segment La connecting the rotational centerline of the crankshaft 63 to the rotational centerline of the intermediate gear 83. Even more preferable is that the entirety of the first balancer 85 is located below the imaginary line segment La.

[0057] In a side view of the crankcase 51, the first equalizer 85 covers at least a portion of the vent chamber 67. In other words, in a side view of the crankcase 51, the vent chamber 67 covers at least a portion of the first equalizer 85. The coverage between the first equalizer 85 and the vent chamber 67 can be a partial or complete overlap. That is, at least a portion of the first equalizer 85 can overlap the vent chamber 67, or at least a portion of the vent chamber 67 can overlap the first equalizer 85.

[0058] Fig. 3 is a plan view of the internal combustion engine according to the embodiment of the invention.

[0059] As in Fig. 3, the balancer mechanism 66 of the engine 9 of this embodiment includes a pair of idler bearings 87a and 87b for rotatably supporting the intermediate gear 83 to the crankcase 51, and a pair of balancer bearings 88a and 88b for rotatably supporting the first balancer 85 to the crankcase 51.

[0060] The paired idle bearings 87a and 87b and the paired balancer bearings 88a and 88b are formed integrally with the crankcase 51.

[0061] The left balancer bearing 88a is offset from each of the idler bearings 87a and 87b in the direction along the rotational centerline of the crankshaft 63. The right balancer bearing 88b is also offset from each of the idler bearings 87a and 87b in the direction along the rotational centerline of the crankshaft 63. In other words, the left balancer bearing 88a is not aligned with any of the idler bearings 87a and 87b in the direction along the rotational centerline of the crankshaft 63, and the right balancer bearing 88b is not aligned with any of the idler bearings 87a and 87b in the direction along the rotational centerline of the crankshaft 63.

[0062] It is sufficient if at least one of the pair of balancer bearings 88a and 88b is offset with respect to the paired idler bearings 87a and 87b in the direction along the rotational centerline of the crankshaft 63. Specifically, when the left balancer bearing 88a is offset with respect to the left idler bearing 87a, the right balancer bearing 88b may be aligned with the right idler bearing 87b. The direction of the offset may be the right direction of the ball housing 51 or the left direction of the crankcase 51. Further, when the right balancer bearing 88b is offset with respect to the right idler bearing 87b, the left balancer bearing 88a may be aligned with the left idler bearing 87a. The direction of the offset may be the right direction of the crankcase 51 or the left direction of the crankcase 51.

[0063] The positional relationship between the balancer bearings 88a and 88b and the idler bearings 87a and 87b is similar to the positional relationship between both shaft end portions of the intermediate gear 83 and both shaft end portions of the first balancer 85.

[0064] The first balancer 85 is located closer to the center of the width dimension of the crankcase 51 than the intermediate gear 83. Specifically, the first balancer 85 is located closer to the center in the width direction of the crankcase 51 than the intermediate gear 83, which is located closer to the left side of the crankcase 51.

[0065] The vent chamber 67 is offset toward the right side of the engine 9. The first equalizer 85 is located on the left side of the vent chamber 67.

[0066] The right compensator bearing 88b is integrally formed with the wall separating the vent chamber 67. In particular, the right compensator bearing 88b is integrally formed with the left side wall of the vent chamber 67.

[0067] The arrangement of the intermediate gear 83, the first balancer 85, and the breather chamber 67 can be reversed in the right-left direction of the engine 9. That is, it is sufficient if the first balancer 85 is located closer to the center of the crankcase 51 than the intermediate gear 83, which is located closer to the right side of the crankcase 51. The breather chamber 67 may be offset to the left side of the engine 9, and the first balancer 85 may be located on the right side of the breather chamber 67. In other words, it is sufficient if the breather chamber 67 is offset to either the right or left side of the engine 9, and the first balancer 85 is provided on the other of the right and left sides of the breather chamber 67. The left balancer bearing 88a may be formed integrally with the wall that partitions the breather chamber 67.That is, it is sufficient if one of the paired compensating bearings 88a and 88b is formed integrally with the wall that divides the vent chamber 67.

[0068] Fig. 4 is a partial left side view of the vehicle according to the embodiment of the present invention.

[0069] Fig. 5 is a partial plan view of the vehicle according to the embodiment of the present invention.

[0070] As in Fig. 4 and Fig. 5 in addition to Fig. 2 and Fig. 3, the motorcycle 1 according to the present embodiment includes the anti-lock braking system 18. This anti-lock braking system 18 is supported by the body frame 2, occupies at least a part of the first balancer 85 in a plan view of the body frame 2 ( Fig. 5) and covers at least part of the ventilation chamber 67 in a side view of the body frame 2 ( Fig. 4).

[0071] The right and left main frames 22 of the body frame 2 are joined and connected to each other at the rear end portion of the elongated stretched section, as well as at the upper end portion of the short straight section. The connecting portion of the right and left main frames 22 is located on the center line C extending in the front-rear direction of the motorcycle 1 and the body frame 2.

[0072] The anti-lock braking system 18 is supported by a bracket 89 that extends forward from the connecting area of ​​the left main frame 22 and reaches above the crankcase 51 of the engine 9, above the first balancer 85, behind the cylinder 52, and adjacent to the breather chamber 67. The anti-lock braking system 18 is located directly above the first balancer 85 and extends just above the intermediate gear 83. This means that the anti-lock braking system 18 also covers at least part of the intermediate gear 83 in a plan view of the body frame 2.

[0073] In a plan view of the body frame 2, the anti-lock braking system 18 covers at least a portion of the first balancer 85. In other words, in a plan view of the crankcase 51, the first balancer 85 covers at least a portion of the anti-lock braking system 18. Note that the overlap between the anti-lock braking system 18 and the first balancer 85 can be partial or complete. This means that at least a portion of the anti-lock braking system 18 can overlap the first balancer 85, or at least a portion of the first balancer 85 can overlap the anti-lock braking system 18.

[0074] Furthermore, in a side view of the body frame 2, the anti-lock braking system 18 covers at least a portion of the vent chamber 67. In other words, in a side view of the crankcase 51, the vent chamber 67 covers at least a portion of the anti-lock braking system 18. Note that the overlap between the anti-lock braking system 18 and the vent chamber 67 may be partial or complete. That is, at least a portion of the anti-lock braking system 18 may overlap the vent chamber 67, or at least a portion of the vent chamber 67 may overlap the anti-lock braking system 18.

[0075] The rotational centerline of the first balancer 85 is located below the horizontal line HL, which is in contact with the upper end of the intermediate gear 83 in the as-built vehicle state. It is more desirable that the entire first balancer 85 be located below the horizontal line HL.

[0076] The breather chamber 67 of the engine 9 is offset to the right of the center line C, which runs in the fore-aft direction of the body frame 2. The first equalizer 85 is located on the left side of the breather chamber 67.

[0077] The arrangement of the intermediate gear 83, the first balancer 85, and the breather chamber 67 can be reversed in the right-left direction of the body frame 2. That is, the breather chamber 67 can be offset to the left side from the center line C extending in the front-back direction of the body frame 2, and the first balancer 85 can be located on the right side of the breather chamber 67. In other words, it is sufficient that the breather chamber 67 is offset to either the right or left side of the center line C extending in the front-back direction of the body frame 2, and the first balancer 85 is located on the other of the right and left sides of the breather chamber 67.

[0078] A lubrication system 91 of the engine 9 will be described below.

[0079] Fig. 6 is a schematic diagram of the lubrication system of the internal combustion engine according to the embodiment of the invention.

[0080] As in Fig. 6, the engine 9 of this embodiment includes the lubrication system 91 provided in the crankcase 51, the cylinder 52 and the cylinder head 53 to circulate the lubricating oil.

[0081] In addition, the engine 9 includes the oil pan 56, which is located at the bottom of the crankcase 51 and stores lubricating oil.

[0082] The lubrication system 91 supplies the lubricating oil in the oil pan 56 to a part to be lubricated, including the crankshaft 63, the pistons 74, a valve mechanism 93 in the cylinder head 53, the countershaft 71 of the transmission 65, and the drive shaft 72 of the transmission 65, to lubricate these parts and to cool them.

[0083] The lubrication system 91 includes an oil pump 95 for sucking the lubricating oil from the oil pan 56, an oil cooler 96 for cooling the lubricating oil discharged from the oil pump 95, an oil filter 97 for removing contamination (i.e., foreign matter) from the lubricating oil discharged from the oil pump 95 and the lubricating oil cooled by the oil cooler 96, and a main bore 98 into which the lubricating oil purified by the oil filter 97 flows.

[0084] The oil cooler 96 is preferably arranged so as to avoid the location where the oil cooler 96 is opposite the front fender of the front wheel 5, so that the oil cooler 96 is freely exposed to the wind of the motorcycle 1.

[0085] The lubrication system 91 includes a main axle bearing lubricating oil passage 101 branching from the main bore 98 and supplying the lubricating oil to an axle bearing portion 99 of the crankcase 51 supporting the crankshaft 63, a crankpin lubricating oil passage 103 for supplying the lubricating oil from the main axle bearing lubricating oil passages 101 to a crankpin 102 via a lubricating oil passage inside the crankshaft 63, and a magneto lubricating oil passage 106 branching from the main axle bearing lubricating oil passage 101 and supplying the lubricating oil to the magneto 105.

[0086] The lubrication system 91 further includes a piston cooling oil channel 108 (i.e., a so-called piston nozzle) for spraying the lubricating oil arriving from the main bore 98 via the secondary bore 107 onto the piston 74.

[0087] The lubrication system 91 further includes a chain tensioner lubricating oil passage 111 and a valve mechanism lubricating oil passage 115. The chain tensioner lubricating oil passage 111 branches off from the main axle bearing lubricating oil passage 101 and supplies the lubricating oil to a camshaft chain tensioner 109. The valve mechanism lubricating oil passage 115 branches off from the chain tensioner lubricating oil passage 111 to reach the cylinder head 53 and supplies the lubricating oil to an intake-side camshaft 112 and an exhaust-side camshaft 113 of a valve mechanism (not shown). The camshaft chain tensioner 109 adjusts the tension of a camshaft chain (not shown), which transmits torque from the crankshaft 63 to the intake-side camshaft 112 and the exhaust-side camshaft 113 of the valve mechanism.

[0088] The lubrication system 91 further includes a compensator lubricating oil channel 121, which branches off from the main bore 98 and supplies the lubricating oil to the second compensator 86.

[0089] Fig. 7 is a partial perspective view of the lubrication system of the internal combustion engine according to the embodiment of the invention.

[0090] The solid arrow “A” in Fig. 7 means the direction parallel to the rotational center line of the crankshaft 63. The solid arrow “f” in Fig. 7 means the flow direction of the lubricating oil in the lubrication system 91.

[0091] As in Fig. 6 and Fig. As shown in Fig. 7, the lubrication system 91 of the engine 9 according to the present embodiment includes an intermediate gear lubricating oil passage 122 and a countershaft lubricating oil passage 123. The intermediate gear lubricating oil passage 122 branches off from the main bore 98 to supply lubricating oil to the intermediate gear 83, and the countershaft lubricating oil passage 123 branches off from the intermediate gear lubricating oil passage 122 to supply lubricating oil to the countershaft 71 of the transmission 65. The countershaft lubricating oil passage 123 includes a first common lubricating oil passage 125 shared with the intermediate gear lubricating oil passage 122. The countershaft lubricating oil passage 123 branches off from the first common lubricating oil passage 125 and reaches the countershaft 71.

[0092] The lubrication system 91 also includes a balancer lubrication oil passage 126 and a drive shaft lubrication oil passage 127. The balancer lubrication oil passage 126 branches off from the main bore 98 to supply the lubricating oil to the first balancer 85, and the drive shaft lubrication oil passage 127 branches off from the balancer lubrication oil passage 126 to supply the lubricating oil to the drive shaft 72 of the transmission 65. The drive shaft lubrication oil passage 127 includes a second common lubrication oil passage 128, which is used in common with the balancer lubrication oil passage 126. The drive shaft lubrication oil passage 127 branches off from the second common lubrication oil passage 128 and reaches the drive shaft 72.

[0093] The intermediate gear lubricating oil passage 122 and the balancer lubricating oil passage 126 are independent of each other as separate passages and branch separately from the main bore 98. This means that the intermediate gear lubricating oil passage 122 and the balancer lubricating oil passage 126 do not meet until the intermediate gear lubricating oil passage 122 reaches the intermediate gear 83, and are not merged until the balancer lubricating oil passage 126 reaches the first balancer 85. The intermediate gear lubricating oil passage 122 reaches one of the right and left shaft end portions of the intermediate gear 83, for example, the right shaft end portion 83a. The balancer lubricating oil passage 126 reaches one of the right and left shaft end portions of the first balancer 85, for example, the right shaft end portion 85a.

[0094] The balancer lubricating oil passage 126 passes through one of the right and left side walls of the crankcase 51, for example, the right side wall 51c ( Fig. 8). In other words, the balancer lubricating oil passage 126 is formed with a partial portion inside either the right or left side wall of the crankcase 51, for example, the right side wall 51c. Among the respective portions of the balancer lubricating oil passage 126, the portion formed in the right side wall 51c corresponds to the second common lubricating oil passage 128. The second common lubricating oil passage 128 passes through the right side wall 51c on the side remote from the first balancer 85 among the right and left side walls of the crankcase 51.

[0095] The inter-gear lubricating oil passage 122 extends through the interior of one of the right side wall of the crankcase 51, the left side wall of the crankcase 51, and an end wall located midway between the right and left side walls of the crankcase 51, which separates the crank chamber 61. For example, the inter-gear lubricating oil passage 122 extends through the interior of the end wall adjacent to the right side wall 51c. In other words, the inter-gear lubricating oil passage 122 includes a portion formed inside one of the right side wall of the crankcase 51, the left side wall of the crankcase 51, and the end wall that divides the crankcase 51 and is midway between the right and left side walls of the crankcase 51. For example, the inter-gear lubricating oil passage 122 includes a region formed inside the end wall adjacent to the right side wall 51c.Among the respective areas of the intermediate gear lubricating oil passage 122, the portion formed inside the side walls or the end wall corresponds to the first common lubricating oil passage 125.

[0096] The intermediate gear lubricating oil passage 122 may extend through the journal bearing portion 99 of the crankcase 51. In other words, the intermediate gear lubricating oil passage 122 may include a portion formed in the journal bearing portion 99 of the crankcase 51. In this case, of the respective portions of the intermediate gear lubricating oil passage 122, the portion formed in the journal bearing portion 99 corresponds to the first common lubricating oil passage 125.

[0097] The first balancer 85 is located at a position closer to one of the side walls than the intermediate gear 83, for example, closer to the right side wall 51c. That is, the first balancer 85 is located closer to the second common lubricating oil passage 128 than the intermediate gear 83.

[0098] The countershaft lubricating oil channel 123 branches off from the intermediate gear lubricating oil channel 122 and reaches the shaft end area on the left side of the countershaft 71.

[0099] The drive shaft lubricating oil passage 127 branches off from the balancer lubricating oil passage 126 and reaches the shaft end area on the right side of the drive shaft 72.

[0100] The intermediate gear lubrication oil passage 123 may branch off from the balancer lubrication oil passage 126. This means that the intermediate gear lubrication oil passage 123 may share the common lubrication oil passage 125 with the balancer lubrication oil passage 126. Furthermore, the drive shaft lubrication oil passage 127 may branch off from the intermediate gear lubrication oil passage 122. This means that the drive shaft lubrication oil passage 127 may share the second common lubrication oil passage 128 with the intermediate gear lubrication oil passage 122.In other words, the lubrication system 91 includes: the countershaft lubricating oil passage 123, which includes the first common lubricating oil passage 125 shared with one of the intermediate gear lubricating oil passage 122 and the balancer lubricating oil passage 126, and branching from the first common lubricating oil passage 125 to reach the countershaft 71; and the drive shaft lubricating oil passage 127, which includes the second common lubricating oil passage 128 shared with the other of the intermediate gear lubricating oil passage 122 and the balancer lubricating oil passage 126, and branching from the second common lubricating oil passage 128 to reach the drive shaft 72.

[0101] Fig. 8 is a partial sectional view of the lubricating system of the internal combustion engine according to the embodiment of the invention.

[0102] Fig. 8 is a cross-sectional view of the engine 9. The Fig.The cross-sectional view shown in Fig. 8 crosses the rotational center line of the first balancer 85 and is orthogonal to the mating surface 51a of the crankcase 51.

[0103] The crankcase 51 includes a balancer housing 129 that houses the first balancer 85 and is spatially connected to the transmission chamber 62. The left side wall portion of the balancer housing 129 includes a through hole 129a through which the left shaft end portion of the first balancer 85 protrudes from the housing.

[0104] The vent chamber 67 is divided by a lower half partition 135 protruding from the top of the upper housing 68, which divides an upwardly open space (this is the lower half of the vent chamber 67), and by a vent cover 136 that closes off the lower half partition 135 from above. The lower half partition 135 is integrally formed with the upper housing 68. The vent cover closes off the lower half partition 135 and is fixed to the upper housing 68 by means of fastening elements (not shown), such as bolts and nuts.

[0105] The balancer housing 129 and the breather chamber 67 are opposite each other in the width direction of the crankcase 51. The right wall of the balancer housing 129 is opposite the left wall of the breather chamber 67.

[0106] One of the balancer bearings 88a and 88b, for example, the right balancer bearing 88b, is integrally formed with the wall that divides the vent chamber 67. The right balancer bearing 88b is integrally formed with the left side wall of the vent chamber 67. The right balancer bearing 88b is integrally formed with the lower half partition wall 135 that divides the lower half of the vent chamber 67.

[0107] The balancer lubricating oil passage 126 crosses the breather chamber 67 in a plan view of the crankcase 51 and reaches the first balancer 85. In other words, in the width direction of the engine 9 (that is, the right-left direction of the engine 9 or the rotation center line direction of the crankshaft 63), the breather chamber 67 is sandwiched between the first balancer 85 and the second common lubricating oil passage 126, which is commonly used by the drive shaft lubricating oil passage 127 and the balancer lubricating oil passage 126.

[0108] The balancer lubricating oil passage 126 extends through the interior of the bottom wall 67a of the vent chamber 67. The balancer lubricating oil passage 126 extends through the interior of the bottom wall 67a of the vent chamber 67, rises within the left side wall 67b of the vent chamber 67, extends along the right balancer bearing 88b at this rising portion, and reaches the right shaft end portion of the first balancer 85.

[0109] The first balancer 85 is located directly above the countershaft gear 79. The first balancer 85 can be located directly above the drive gear 81, or directly above both the countershaft gear 79 and the drive gear 81 to straddle both. In other words, it is sufficient if the first balancer 85 is located directly above at least one of the countershaft gear 79 and the drive gear 81.

[0110] The first balancer 85 protrudes from the balancer housing 129 and enters the interior of the gear chamber 62. That is, the first balancer 85 protrudes further from the imaginary plane P than the lower end surface of the balancer housing 129 and enters the interior of the gear chamber 62.

[0111] A weight 138 of the first balancer 85 is located directly above the higher gear of the gear pairs 78 of the transmission gears 75. The weight 138 extends radially outward from the first balancer 85. For example, the weight 138 is located directly above the fourth to sixth gear pairs 78 in the six-speed transmission 65, which can shift from first gear to sixth gear. Instead of the weight 138, a balancer gear 139 can be arranged directly above the higher gear of the gear pairs 78 in the transmission gears 75.

[0112] The motorcycle 1 according to the present embodiment includes the idler gear 83 at the rear of the crankshaft 63, and the first balancer 85 is located behind the idler gear 83. The idler gear 83 and the first balancer 85 extend along the ceiling wall 51b of the crankcase 51. Consequently, the arrangement of the idler gear 83 and the first balancer 85 of the motorcycle 1 is reduced in terms of upward protrusion behind the cylinder 52 compared to the conventional vehicle. That is, the motorcycle 1 can easily leave a clearance behind the cylinder 52 and above the crankcase 51.This free space facilitates an increase in the capacity of the fuel tank 12, provides accommodation space for the intake system 11 of the engine 9 including the air filter 25 and the throttle body 27, and provides further accommodation space for devices such as the anti-lock braking system 18, so that the degree of freedom for the arrangement of these parts is increased.

[0113] Furthermore, the motorcycle 1 of the present embodiment includes the breather chamber 67, which covers at least a portion of the first balancer 85 in a side view of the engine 9. That is, the first balancer 85 and the breather chamber 67 of the motorcycle 1 are collectively arranged and compactly mounted. Consequently, the motorcycle 1 can easily maintain available space behind the cylinder 52 and above the crankcase 51.

[0114] Furthermore, the motorcycle 1 of the present embodiment includes the breather chamber 67 offset to either the right or left side with respect to the center line extending in the front-rear direction of the body frame 2 because the first equalizer 85 is located on the other of the right and left sides of the breather chamber 67. In other words, the breather chamber 67 and the first equalizer 85 are arranged to be distributed on the right and left sides of the motorcycle 1, respectively. Accordingly, the motorcycle 1 can easily maintain a clearance both behind the cylinder 52 and above the crankcase 51, and increase the capacity of the breather chamber 67.

[0115] Furthermore, the motorcycle 1 according to the present embodiment includes the anti-lock braking system 18, which covers at least a part of the first balancer 85 in a plan view of the body frame 2. Accordingly, in the motorcycle 1, the center of gravity of the anti-lock braking system 18 is located closer to the center of gravity of the motorcycle 9, and further, the center of gravity of the anti-lock braking system 18 is located closer to the center of gravity of the entire vehicle, which improves its handling characteristics.

[0116] Furthermore, the motorcycle 1 of the present embodiment includes the anti-lock braking system 18, which covers at least a portion of the first equalizer 85 in a plan view of the body frame 2 and covers at least a portion of the breather chamber 67 in a side view of the body frame 2. Consequently, the motorcycle 1 brings the center of gravity of the anti-lock braking system 18 closer to the center of gravity of the engine 9 and also brings the center of gravity of the anti-lock braking system 18 closer to the center of gravity of the entire vehicle, improving its handling. Furthermore, the breather chamber 67 of the motorcycle 1 is adapted to the arrangement of the anti-lock braking system 18 and can have a large capacity.Since the anti-lock braking system 18 and the breather chamber 67 are collectively arranged to be close to each other within the motorcycle 1, the motorcycle 1 facilitates the layout of peripheral components such as a battery (not shown) and the rear damper unit 33 located at the rear, as well as the air cleaner 25, the throttle body 27, and the fuel tank 12 at the upper portion.

[0117] Therefore, the motorcycle 1 according to the present embodiment includes the balancer mechanism 66 for reducing the vibration of the engine 9 and can leave a space for increasing the fuel tank size and / or the arrangement of devices or components behind the cylinder and above the crankcase.

[0118] It should be noted that the vehicle according to the invention is not limited to the motorcycle 1, but can be different types of vehicles, for example a saddle tricycle or a four-wheeled vehicle.

Claims

[1] Vehicle (1), comprising: a body frame (2); and an internal combustion engine (9) attached to the body frame (2), wherein the internal combustion engine (9) comprises a crankcase (51) with a ceiling wall (51b), a cylinder (52) located in a front end region of an upper side of the crankcase (51), a ventilation chamber (67) on the top of the crankcase (51), a crankshaft (63) provided in the crankcase (51) and rotatably mounted, and a balancing mechanism (66) located in the crankcase (51) configured to reduce the vibration of the internal combustion engine (9) by force transmitted from the crankshaft (63); wherein the balance mechanism (66) comprises an idle gear (83) behind the crankshaft (63), rotated by the power transmitted from the crankshaft (63), and a balancer (85) behind the idle gear (83), rotated by the power transmitted from the idle gear (83); wherein the idle gear (83) and the balancer (85) are arranged along the ceiling wall (51b), wherein the balancer (85) is arranged such that the rotational center line of the balancer (85) lies below an imaginary line segment (La) connecting the rotational center line of the idle gear (83) and the rotational center line of the crankshaft (63), and wherein the venting chamber (67) is located behind the cylinder and covers at least a part of the equalizer (85) in a side view of the internal combustion engine (9), further comprising an anti-lock braking system (18) which is supported by the body frame (2), covers at least a part of the equalizer (85) in a plan view of the body frame (2), and covers at least a part of the venting chamber (67) in a side view of the body frame (2). [2] A vehicle (1) according to claim 1, wherein the breather chamber (67) is offset to one of the right and left sides with respect to a center in the front-rear direction of the body frame (2); and the equalizer (85) is arranged on the other of the right and left sides of the breather chamber (67).

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