WO2005040579A1

WO2005040579A1 - Engine for saddle riding-type vehicle and saddle riding-type vehicle with the same

Info

Publication number: WO2005040579A1
Application number: PCT/JP2004/014719
Authority: WO
Inventors: Tatsuya Masuda; Yousuke Ishida
Original assignee: Yamaha Hatsudoki Kabushiki Kaisha
Priority date: 2003-10-23
Filing date: 2004-10-06
Publication date: 2005-05-06
Also published as: CN100520010C; JP2007022098A; CN1871417A

Abstract

An engine has components and devices such as a cylinder block (19) inside which a cylinder is formed, a crankshaft (28), a drive shaft (48), an automatic speed changer, and a balancer weight (129a). The automatic speed changer has a primary sheave, a secondary sheave, and a V-belt carried on the primary sheave and the secondary sheave. The automatic speed changer is received in a speed changer case (45). In a side view, the axis (C) of the crankshaft (28) is offset upward from the center line (A) of the cylinder.

Description

Specification

Saddle-ride type vehicle engine and saddle-ride type vehicle provided with the same

Technical field

The present invention relates to a straddle-type vehicle engine and a straddle-type vehicle provided with the same.

Background art

[0002] Saddle-riding vehicles are widely used, for example, as motorcycles. Generally, in an engine such as a motorcycle, a cylinder block, a crankcase, and the like are formed such that an axis of the cylinder block (that is, a center line of the cylinder) intersects with an axis of a crankshaft. On the other hand, there is also known an engine in which the axis of the cylinder block is offset from the axial force of the crankshaft in order to reduce the length of the engine in the front-rear direction. Japanese Patent Application Laid-Open No. 2002-227601 (hereinafter referred to as Patent Document 1) discloses such an engine.

[0003] The engine disclosed in Patent Document 1 includes a transmission housed in a crankcase. The transmission includes a speed change input shaft, a speed change output shaft, and a plurality of speed change gear trains arranged between the speed change input shaft and the speed change output shaft. The speed change input shaft is disposed at a position offset upward with respect to a plane including both the axis of the crank shaft and the speed change output shaft. In this engine, the cylinder block extends forward and upward from the upper front end of the crankcase. The cylinder block is arranged so that the axis of the cylinder block is located forward of the axis of the crankshaft.

[0004] Patent Document 1 describes the following description. That is, in the above-mentioned engine, by adopting the above configuration, even if the speed change input shaft is arranged to some extent above, the speed change input shaft is not obstructed by the cylinder block. Therefore, it is possible to sufficiently increase the upward offset amount of the shift input shaft. When the amount of upward shift of the shift input shaft is increased, the distance between the crankshaft and the shift output shaft is reduced, and the length of the engine in the front-rear direction is reduced.

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-227601

Disclosure of the invention

Problems the invention is trying to solve [0005] Incidentally, a V-belt type continuously variable transmission may be used for a transmission such as an engine for a motorcycle, in addition to a transmission having a plurality of transmission gear train forces. The engine disclosed in Patent Document 1 does not include a V-belt type continuously variable transmission as a transmission. Therefore, the layout of the above engine could not be used as it is for an engine equipped with a V-belt type continuously variable transmission.

[0006] Further, in an engine of a motorcycle or the like, in addition to a transmission, an auxiliary machine that transmits power to a crankshaft or transmits power to a crankshaft may be provided. In that case, additional space for installing auxiliary equipment is required. In particular, when using auxiliary equipment whose axial length is longer than the radial length (hereinafter referred to as “slender auxiliary equipment”), it is necessary to secure a large space for installing auxiliary equipment. Become. Therefore, in order to realize an efficient layout of the engine, the positional relationship between the transmission and other auxiliary equipment, the arrangement of intake system components, and the like are important.

[0007] However, in the engine disclosed in Patent Document 1, special attention was not paid to the efficient arrangement of the auxiliary equipment. As a result, auxiliary equipment was not efficiently arranged in the engine, and the size of the crankcase and the like was increased. If the size of the crankcase, etc. increases while the force is applied, the space between the crankcase, etc. and the vehicle body becomes smaller, and it becomes difficult to arrange the intake system components above the crankcase.

[0008] Further, in an engine equipped with a balancer, the vibration suppression effect of the balancer can be obtained, but on the other hand, the sliding resistance accompanying driving of the balancer shaft increases, and there is a possibility that the engine performance is reduced. Therefore, it is necessary to provide a layout that considers engine performance when arranging auxiliary equipment.

[0009] The present invention has been made in view of its power, and an object of the present invention is to provide a compact saddle-ride type vehicle engine in which a V-belt type continuously variable transmission and accessories are efficiently arranged. It is to provide

Means for solving the problem

[0010] A straddle-type vehicle engine according to the present invention includes a cylinder block having a cylinder formed therein, a piston provided in the cylinder and reciprocating within the cylinder, and a reciprocating piston. A crankshaft that rotates as it moves, from the axial direction of the crankshaft. A crankshaft whose center is shifted upward from the center line force of the cylinder when viewed, and a crankshaft disposed above the crankshaft when viewed from the axial direction of the crankshaft to transmit power to the crankshaft or Auxiliary machine to which power is transmitted, a drive shaft that outputs rotational driving force, a primary sheave that rotates according to the rotation of the crankshaft, a secondary sheave directly or indirectly connected to the drive shaft, An automatic transmission having a sheave and a transmission belt wound around the secondary sheave.

[0011] In the saddle-ride type vehicle engine, the axial center of the crankshaft (the center of the shaft) is displaced upward from the center line of the cylinder when viewed from the axial force of the crankshaft. In other words, the cylinder is located at a position shifted downward from the crankshaft when viewed from the axial force of the crankshaft. For this reason, an empty space is generated above by an amount corresponding to the displacement of the cylinder downward. Therefore, by arranging auxiliary equipment in the empty space, efficient arrangement of auxiliary equipment is achieved. Even for long and narrow accessories that require a large installation space, efficient arrangement is possible.

[0012] Here, the efficient arrangement refers to, for example, a high-density arrangement, an orderly arrangement, an arrangement in which essential functions such as auxiliary equipment are easily exhibited, and the performance of a saddle-ride type vehicle engine. An arrangement that improves the operation, or an arrangement that improves the operability or getting on and off of a saddle-ride type vehicle.

[0013] The accessory may be disposed above an imaginary line connecting the center of the primary sheave and the center of the secondary sheave when viewed from the axial direction of the crankshaft.

[0014] Thus, the auxiliary equipment is arranged above the automatic transmission, and the efficient arrangement of the auxiliary equipment is achieved.

[0015] The auxiliary machine also has a balancer force.

[0016] Thereby, the vibration suppressing effect of the noranser can be obtained. In the above engine, since the crankshaft is also offset from the center line force of the cylinder, it is possible to suppress an increase in the sliding resistance of the biston due to the balancer.

[0017] The straddle-type vehicle engine includes a cylinder head connected to the cylinder block. An intake or exhaust valve provided in the cylinder head, a cam mechanism provided in the cylinder head for opening and closing the valve, and a transmission member for transmitting a rotational driving force of the crankshaft to the cam mechanism. A transmission member housing chamber for housing the transmission member is defined in the cylinder block, and the cylinder is disposed between the transmission member housing chamber and the automatic transmission in the axial direction of the crankshaft. It is preferable to be located.

[0018] Thus, the automatic transmission and the transmission member accommodating chamber are arranged on opposite sides of the cylinder. Therefore, interference between the automatic transmission and the transmission member housing chamber is avoided, and the degree of freedom in the layout of the automatic transmission is increased.

It is preferable that the primary sheave is cantilevered by the crankshaft.

[0020] Thus, an efficient layout of the automatic transmission can be achieved.

[0021] The saddle-ride type vehicle engine includes at least a crankcase accommodating the crankshaft, and an intake system component directly or indirectly connected to the cylinder head, and at least one of the intake system components. The part is preferably disposed above the cylinder block or the crankcase.

As a result, efficient arrangement of the intake system components is achieved.

[0023] The saddle-ride type vehicle engine includes an intake system component directly or indirectly connected to the cylinder head, and a crankcase accommodating at least the crankshaft, and includes the cylinder block and the crankcase. Constitutes an engine main body, the crankshaft extends in the left-right direction, the automatic transmission is disposed on one of the left and right sides of the engine main body, and the secondary sheave is closer to the primary sheave than the primary sheave. The intake system component may be disposed above the engine body and on the side opposite to the side where the automatic transmission is provided in the left-right direction. preferable.

[0024] As described above, since the secondary sheave is arranged above the primary sheave and the intake system components are arranged above the engine main body, an extra space is generated below the engine main body. Therefore, the layout below the engine body The degree of freedom increases. In the left-right direction, the intake system components are arranged on the side opposite to the side where the automatic transmission is provided, so that interference between the intake system components and the automatic transmission can be effectively avoided, and furthermore An efficient layout can be achieved.

[0025] The straddle-type vehicle engine may include a secondary sheave shaft formed separately from the drive shaft and fitted into the secondary sheave.

[0026] By thus forming the secondary sheave shaft and the drive shaft separately, the degree of freedom of the layout further increases.

[0027] The saddle-ride type vehicle engine includes a transmission case accommodating the automatic transmission, an idle shaft extending in the left-right direction, and a reduction mechanism connected to the secondary sheave shaft and the drive shaft. Wherein the crankshaft extends in the left-right direction, the secondary sheave shaft is disposed above the drive shaft, and the idle shaft is configured such that, when viewed from the side, the axis of the drive shaft and the secondary shaft It is preferable that the drive shaft is disposed closer to the primary sheave side than a virtual line connecting the sheave shaft and the drive shaft, and the drive shaft is disposed inside the contour of the transmission case in a side view. .

[0028] In the above engine, the lower portion of the engine is reduced in size by disposing the secondary sheave shaft above the drive shaft. Therefore, in a straddle-type vehicle, a large space can be secured below the engine. Also, in side view, the idle shaft is located on the primary sheave side with respect to the imaginary line connecting the axis of the drive shaft and the axis of the secondary sheave shaft. Can be reduced in size. For example, when the primary sheave is arranged in front of the engine, the rear part of the engine can be downsized. Therefore, in a saddle-ride type vehicle, a large space can be secured behind the engine. Further, since the drive shaft is positioned inside the contour of the transmission case in a side view, the drive shaft and the automatic transmission can be arranged at a high density in the engine.

[0029] By combining the above-mentioned various factors, that is, a plurality of factors for space saving, downsizing of the saddle-ride type vehicle engine is promoted.

[0030] A straddle-type vehicle according to the present invention includes the saddle-ride type vehicle engine. [0031] The saddle-ride type vehicle includes a head pipe, a front frame that also extends diagonally downward and rearward with the head pipe force, and a rear frame that extends diagonally rearward and upward from the front frame. A vehicle body that supports the saddle-ride type vehicle engine in a position that is located behind the crankshaft, wherein the cylinder block is supported by being suspended from the front frame. Yo,

[0032] Thereby, the engine can be efficiently arranged in a so-called underbone type vehicle.

[0033] The straddle-type vehicle includes a vehicle body that supports the saddle-ride type vehicle engine in a posture such that the drive shaft is located rearward of the crankshaft; A rear arm supported and supporting the rear wheel may be provided, and a driving force transmission member extending in the front-rear direction along the rear arm and transmitting driving force from the drive shaft to the rear wheel.

[0034] In general, in a vehicle that transmits driving force to the rear wheels via a driving force transmitting member, the effect of friction in the engine tends to increase, but according to the present engine, the effect of friction can be suppressed. .

[0035] The support point of the lear arm in the vehicle body may be located behind the saddle-ride type vehicle engine in a side view.

[0036] A support point of the lear arm in the vehicle body may be located below an axis of the secondary sheave.

[0037] The support point of the lear arm in the vehicle body is preferably located near the rear of the drive shaft! /.

[0038] This makes it possible to suppress a decrease in the transmission efficiency of the driving force transmission member when the lear arm swings around the support point.

The invention's effect

As described above, according to the present invention, a compact saddle-ride type vehicle engine in which a V-belt type continuously variable transmission and auxiliary devices are efficiently arranged can be realized. Brief Description of Drawings

FIG. 1 is a left side view of a motorcycle according to an embodiment of the present invention. [2] FIG. 2 is a perspective view in which a left side surface of the engine according to the embodiment of the present invention is seen through, and a part of which is a sectional view.

FIG. 3 is a cross-sectional view taken along line ΠΙ-ΠΙ of FIG. 2.

FIG. 4 is a partial sectional view of the engine unit.

FIG. 5 is a cross-sectional view taken along line VV of FIG. 2.

[6] Fig. 6 is a left side view of the engine unit showing a positional relationship among a starter cell motor, a crankshaft, a lancer shaft, a drive shaft, and the like. Explanation of symbols

1 Motorcycle (saddle-ride type vehicle)

16 Automatic transmission

19 Cylinder block

19b cylinder

22 crankcase

28 crankshaft

48 drive shaft

55 Primary Sheave

56 Secondary sheave

57 V belt (transmission belt)

129a Balancer weight (Auxiliary equipment)

154 Intake system parts

A Cylinder center line

C Crankshaft shaft center

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiments described below are exemplifications for explaining the present invention, and the present invention is not limited only to these embodiments. Therefore, the present invention can be implemented in various modes without departing from the gist thereof. Note that the terms front and rear, left and right in the present embodiment mean front and rear as viewed in the state of sitting on a motorcycle seat (the traveling direction is forward), and left and right. To do.

FIG. 1 shows a motorcycle 1 including the engine according to the present embodiment. As will be described later in detail, the engine according to the present embodiment is a continuously variable transmission engine. A head pipe 3 is fixed to the front end of the vehicle frame la. A front fork 5 is supported on the head pipe 3 so as to be rotatable in the left-right direction. At the lower end of the front fork 5, a front wheel 4 is rotatably supported.

A rear arm bracket 6 is disposed at the center in the front-rear direction of the vehicle body. The Lear arm 8 is supported on the Lear arm bracket 6 via a pivot shaft (support point) 100. The rear arm 8 is rotatably supported by a pivot shaft 100. Therefore, the rear arm 8 is provided so as to be vertically swingable about the pivot shaft 100. A rear wheel 7 is rotatably supported at the rear end of the rear arm 8. A seat 9 is disposed above the body frame la. The seat 9 also includes a driver seat portion 9a and a rear passenger seat portion 9b. Although details will be described later, the engine unit 2 is attached to the vehicle body frame la in such a manner that a drive shaft 48 (see FIG. 3) for outputting a rotational driving force is located behind the crankshaft 28. In the engine unit 2, the pivot shaft 100 of the rear arm 8 is located behind the engine unit 2 and is located near the rear of the drive shaft 48.

[0045] As shown in FIG. 1, the vehicle body frame la includes a down tube lb extending obliquely downward and rearward from the head pipe 3, an upper tube lc extending obliquely upward following the rear end of the down tube lb, and a down tube lb. And the upper tube lc, and the seat rail Id and the force that extend in the front-rear direction between the down tube lb and the upper tube lc are also configured. The down tube lb, the upper tube lc, and the seat rail 1d are provided on both left and right sides of the vehicle body, respectively.

The vehicle body frame la is covered with a cover 10 made of resin. The cover 10 includes a front cover 10a, a redder shield 10b, a side cover 10c, and the like. A steering handle 11 covered with a handle cover 11a is fixed to an upper end of the front fork 5. A lya cushion (shock absorber) 12 is provided between the lear arm 8 and the lear arm bracket 6. [0047] The engine unit 2 is supported by the down tube lb of the vehicle body frame la in a suspended state. The engine unit 2 has an air-cooled four-cycle single-cylinder engine as the engine body 15 (see Fig. 3). The cylinder axis of the engine body 15 (that is, the center line of the cylinder 19b) is approximately 45 degrees away from the horizontal axis. Degrees. However, the angle between the cylinder axis A and the horizontal axis (standing angle) is not limited at all. The cylinder axis A may extend substantially horizontally.

Next, the configuration of the engine unit 2 will be described in detail with reference to FIGS.

As shown in FIG. 3, the engine unit 2 includes an engine body 15, a V-belt type continuously variable automatic transmission 16, a wet multi-plate centrifugal clutch 17, and a reduction mechanism 18.

[0050] The engine body 15 includes a cylinder block 19, a cylinder head 20, and a crankcase 22. The cylinder head 20 is connected to the upper mating surface of the cylinder block 19. A head cover 21 is provided above the cylinder head 20. The crankcase 22 is connected to a lower mating surface of the cylinder block 19. The crankcase 22 supports a crankshaft 28 and a secondary sheave shaft (transmission shaft) 47.

[0051] An intake port (not shown) communicating with the combustion recess 20a is opened on the rear surface of the cylinder head 20. The intake port is connected to a carburetor 23 via an intake pipe 23a (see FIG. 1). In this embodiment, the intake pipe 23a extends rearward, but the intake pipe 23a may extend forward (see a two-dot chain line in FIG. 2). On the other hand, an exhaust port (not shown) communicating with the combustion recess 20a is opened on the front surface of the cylinder head 20. An exhaust pipe 24 (see FIG. 1) is connected to this exhaust port. As shown in FIG. 1, the exhaust pipe 24 extends obliquely rearward and downward, then extends obliquely upward and rearward through the right side of the engine body 15 and is connected to the muffler 25. The muffler 25 is disposed on the right side of the rear wheel 7. As shown in FIG. 3, a spark plug 30 is inserted inside the combustion recess 20a.

On the left side of the cylinder block 19, a cam chain chamber 19a that connects the inside of the crankcase 22 and the inside of the cylinder head 20 is formed. A timing chain 34 is provided in the cam chain chamber 19a. The timing chain 34 is wound around the crankshaft 28 and the camshaft 31. The camshaft 31 rotates according to the rotation of the crankshaft 28, and opens and closes an intake valve and an exhaust valve (not shown). However, the transmission member that transmits the rotational driving force of the crankshaft 28 to the camshaft 31 is not limited to the timing chain 34. For example, a transmission belt, a push rod, or the like can be used as the transmission member.

[0054] A piston 26 is slidably inserted into the cylinder 19b of the cylinder block 19. A small end 27b of a connecting rod 27 is connected to the piston 26. A crank pin 29 is provided between the left crank arm 28a and the right crank arm 28b of the crank shaft 28. The large end 27a of the connecting rod 27 is connected to the crankpin 29. Reference numeral 32 indicates a cylinder sleeve.

[0055] The crankcase 22 includes two divided cases, that is, a first case 40 on the left and a second case 41 on the right. The mating surface between the first case 40 and the second case 41, that is, the split surface D of the crank case 22 extends parallel to the center line A of the cylinder 19b. However, the split plane D does not coincide with the center line A, and is offset to the left of the center line A.

[0056] On the right side of the second case 41, a case cover 71 is attached. An opening is formed on the right side of the second case 41, and the case cover 71 covers the opening. The case cover 71 is detachably fixed to the second case 41 by bolts 72. Therefore, the case cover 71 is easy to attach and detach. By removing the case cover 71 from the second case 41, the centrifugal clutch 17 and the secondary sheave shaft 47 can be easily removed.

[0057] On the left front side of the first case 40, a generator case 44 accommodating the generator 42 is detachably attached. On the right side of the second case 41, a transmission case 45 accommodating the automatic transmission 16 is attached. The automatic transmission 16 is housed in a transmission room partitioned by a transmission case 45.

[0058] The transmission case 45 is formed independently of the crankcase 22, and also includes a case body 45a, a lid 45b, and a force. The case body 45a is arranged on the right side of the second case 41, and opens on the right side. The lid 45b is disposed on the right side of the case main body 45a, and seals an opening on the right side of the case main body 45a. The case body 45a, the lid 45b, and the second case 41 are integrally fixed by bolts 70. The bottom wall 45c of the case body 45a and the Between the two cases 41, a gap a is provided. As described above, the case body 45a and the second case 41 are separated from each other, so that heat from the engine body 15 is prevented from being transmitted to the transmission case 45. The right side of the transmission case 45 is covered with a decorative cover 60.

[0059] On the front side (upper side in FIG. 3) of the crankcase 22, a crankshaft 28 is disposed so as to extend in the left-right direction. The left side of the central portion of the crankshaft 28 is rotatably supported by a first case 40 via a bearing 35. On the other hand, the right side of the central portion of the crankshaft 28 is rotatably supported by the second case 41 via the bearing 36.

The right end of the crankshaft 28 extends into the transmission case 45 beyond the second case 41. A primary sheave (drive bull) 55 of the automatic transmission 16 is coaxially fitted to the right end of the crankshaft 28. Therefore, the primary sheave 55 rotates according to the rotation of the crankshaft 28. The right end of the crankshaft 28 forms a primary sheave shaft. However, the mode of connection between the primary sheave 55 and the crankshaft 28 is not limited to the above-described mode. The primary sheave shaft and the crankshaft 28 may be formed separately. The primary sheave shaft may not necessarily be arranged coaxially with the crankshaft 28, but may be arranged parallel to the crankshaft 28, for example. Further, the term "connection" as used herein means a connection in a broad sense, and is specifically specified to be!, Na! /, As long as it is directly connected! Connected to!

[0061] On the other hand, the left end of the crankshaft 28 extends into the generator case 44 beyond the first case 40. Further, a generator 42 is attached to the left end of the crankshaft 28. A seal member 37 is provided between a portion of the right end surface of the second case 41 on which the crankshaft 28 extends and a bottom wall 45c of the transmission case 45. Thereby, the second case 41 is sealed with respect to the transmission case 45. Therefore, a wet type clutch can be used as the clutch housed in the second case 41. As described above, in this embodiment, the wet multi-plate centrifugal clutch 17 is used as the clutch.

[0062] The generator 42 includes a stator 42b and a rotor 42a facing the stator 42b.

The rotor 42a is fixed to a sleeve 43 that rotates together with the crankshaft 28. In addition, pickpocket The tapered portion of the crankshaft 28 is fitted into the bead 43. The stator 42b is fixed to the generator case 44.

[0063] A secondary sheave shaft 47 parallel to the crankshaft 28 is disposed on the rear side (the lower side in FIG. 3) of the crankcase 22. The right part of the center of the secondary sheave shaft 47 is supported by the case cover 71 via the bearing 38! The left portion of the central portion of the secondary sheave shaft 47 is supported by the left end of the second case 41 via a bearing 39. The right end of the secondary sheave shaft 47 extends into the transmission case 45 beyond the second case 41. A secondary sheave (driven pulley) 56 of the automatic transmission 16 is connected to a right end of the secondary sheave shaft 47. Here, the secondary sheave 56 is coaxially connected to the secondary sheave shaft 47.

The centrifugal clutch 17 is mounted on the left side of the secondary sheave shaft 47.

The centrifugal clutch 17 is disposed on the left side of the secondary sheave 56, that is, on the cylinder block 19 side. Such an arrangement is achieved by the large internal space of the second case 41. That is, in the present engine unit 2, the dividing plane D of the crankcase 22 is located on the left side of the center line A of the cylinder 19b, and a wide space is secured inside the second case 41. Therefore, it is possible to arrange the centrifugal clutch 17 on the left side of the secondary sheave 56.

The centrifugal clutch 17 is a wet multi-plate centrifugal clutch, and includes an inner clutch 84 and a bowl-shaped outer clutch 83. The outer clutch 83 is spline-fitted to the secondary sheave shaft 47, and rotates together with the secondary sheave shaft 47, while freely moving in the axial direction of the secondary sheave shaft 47. The inner clutch 84 is disposed coaxially inside the outer clutch 83. The inner clutch 84 is spline-fitted to the small reduction gear 74 on the primary side, and the small reduction gear 74 rotates together with the inner clutch 84. The small reduction gear 74 is rotatably supported by the secondary sheave shaft 47.

As shown in FIG. 4, inside the outer clutch 83, a plurality of outer clutch plates 85 are arranged. Press plates 86 are disposed on both left and right ends of the outer clutch plate 85, respectively. The outer clutch plate 85 and the pressing plate 86 are locked to the outer clutch 83 so as to rotate together with the outer clutch 83. Presser plate with a quarter clutch plate 85 An inner clutch plate 87 is provided between the inner clutch plate 87 and the inner plate 86. The inner clutch plate 87 is locked to the outer peripheral portion of the inner clutch 84 so as to rotate together with the inner clutch 84.

[0067] Inside the outer clutch 83, a cam surface 83a protruding leftward is formed. A weight 88 is provided between the cam surface 83a and the right pressing plate 86. When the rotation speed of the outer clutch 83 becomes equal to or higher than a predetermined speed, the weight 88 receives the centrifugal force and moves radially outward. Since the cam surface 83a is formed inside the outer clutch 83, when the weight 88 moves outward in the radial direction, the right pressing plate 86 is pushed leftward by the weight 88 and moves leftward. As a result, the outer clutch plate 85 and the inner latch plate 87 are connected. That is, the clutch is connected. In FIGS. 3 and 4, the front (upper in FIGS. 3 and 4) portion of the centrifugal clutch 17 indicates the disconnected state, and the rear (lower in FIGS. 3 and 4) portion indicates the connected state. It represents.

The V-belt type continuously variable automatic transmission 16 includes a primary sheave 55, a secondary sheave 56, and a V-belt 57 wound around the primary sheave 55 and the secondary sheave 56. As described above, the primary sheave 55 is attached to the right end of the crankshaft 28. Therefore, the driving force of the crankshaft 28 is transmitted to the primary sheave 55. Secondary sheave 56 is connected to the right end of secondary sheave shaft 47.

[0069] The primary sheave 55 includes a fixed pulley half 55a and a movable pulley half 55b facing the fixed pulley half 55a. The fixed pulley half 55a is fixed to the right end of the crankshaft 28, and rotates together with the crankshaft 28. The movable pulley half 55b is disposed on the left side of the fixed pulley half 55a. A slide collar 59 slidable with respect to the crankshaft 28 is attached to the crankshaft 28. The movable pulley half 55b is attached to the crankshaft 28 via the slide collar 59. Therefore, the movable pulley half 55b rotates together with the crankshaft 28 and is movable in the axial direction of the crankshaft 28. A cam plate 58 is provided on the left side of the movable pulley half 55b. A cylindrical weight 61 is disposed between the cam plate 58 and the movable pulley half 55b.

[0070] Secondary sheave 56 is opposed to fixed pulley half 56a and fixed pulley half 56a. And a movable pulley half 56b. The movable pulley half 56b is attached to the right end of the secondary sheave shaft 47. The movable pulley half 56b rotates together with the secondary sheave shaft 47 and is movable in the axial direction of the secondary sheave shaft 47. A coil spring 67 is provided at the right end of the secondary sheave shaft 47, and the movable pulley half 56 b receives a leftward biasing force from the coil spring 67. The fixed pulley half 56a is installed on the left side of the movable pulley half 56b. A cylindrical slide collar 62 is fixed to the axis of the fixed pulley half 56a. The slide collar 62 is spline-fitted to the secondary sheave shaft 47.

[0071] In this automatic transmission 16, the magnitude relationship between the force by which the weight 61 pushes the movable pulley half 55b on the drive side to the right and the force by which the coil spring 67 pushes the movable pulley half 56b on the driven side back to the left. Determines the speed reduction ratio. That is, when the rotation speed of the crankshaft 28 increases, the weight 61 moves radially outward (upward in FIG. 4) due to the centrifugal force, and moves the movable pulley half 55b on the driving side to the right. Then, the movable movable half 56 b on the driven side also moves to the right against the urging force of the coil spring 67. As a result, the winding diameter of the V-belt 57 around the driving pulley 55 increases, and the winding diameter around the driven pulley 56 decreases. Therefore, the reduction ratio becomes small. On the other hand, when the rotation speed of the crankshaft 28 decreases, the centrifugal force of the weight 61 decreases, so that the weight 61 moves radially inward. Therefore, the movable pulley half 55b on the driving side can easily move to the left. Then, the movable pulley half 56b on the driven side moves leftward by receiving the urging force of the coil spring 67, and accordingly, the movable pulley half 55b also moves leftward. As a result, the winding diameter of the V belt 57 on the driving pulley 55 decreases, and the winding diameter of the driven pulley 56 increases. Therefore, the reduction ratio increases.

A lock nut 66 is screwed into the tip of the secondary sheave shaft 47, and the secondary sheave 56 is fixed to the secondary sheave shaft 47 via the lock nut 66. The lock nut 66 is recessed in the right end 62a of the slide collar 62. The inner diameter of the slide collar 62 gradually increases in the axial direction. On the other hand, the right end 47a of the secondary sheave shaft 47 is gradually reduced. In other words, the diameter of the secondary sheave shaft 47 is reduced stepwise toward the distal end. In the present engine unit 2, by adopting such a configuration, the lock nut 66 can be arranged without any trouble inside the right end portion 62 a of the slide collar 62. Therefore, it is possible to position the hook nut 66 on the left side of the spring receiving member 65 of the coil spring 67. Thus, the protrusion on the outside (right side) without shortening the coil spring 67 itself can be reduced. In other words, the engine unit 2 is downsized (widthwise downsized) with a simple structure.

[0074] As shown in FIG. 2, a non-lancer shaft 129 extending parallel to the crank shaft 28 is provided diagonally behind and above the crank shaft 28. As shown in FIG. 5, the right end of the non-lancer shaft 129 is supported by the second case 41 via a bearing 131. On the other hand, the left side of the center of the balancer shaft 129 is supported by the first case 40 via the bearing 130. The left end of the rotor shaft 129 extends outward from the first case 40. At the left end of the balancer shaft 129 extending from the first case 40, a lancer gear 132 is fixed.

The left and right crank arms 28a and 28b of the crankshaft 28 are located between the bearing 130 and the bearing 131. The balancer weight 129a of the balancer shaft 129 (see FIG. 2) is arranged between the crank arm 28a and the crank arm 28b. In addition, as shown in FIG. 2, the balancer weight 129a is arranged at a position close to the crankshaft 28 so as to overlap with the rotation locus of the crankpin 29. As described above, the peripheral components of the balancer shaft 129 (the balancer 129a and the like) are densely arranged. Further, the nolancer shaft 129 is disposed inside the contour (profile) of the transmission case 45 in a side view. The balancer shaft 129 and the balancer weight 129a constitute a balancer as a whole! /

As shown in FIG. 5, a first drive gear 121 is press-fitted into the crankshaft 28. The first drive gear 121 is provided with a second drive gear 127 that rotates together with the first drive gear 121. The second drive gear 127 meshes with the non-lancer gear 132. With such a configuration, the rotation of the crankshaft 28 is transmitted to the nolancer shaft 129 via the first drive gear 121, the second drive gear 127, and the balancer gear 132.

[0077] Between the bearing 35 supporting the crankshaft 28 and the sleeve 43 of the generator 42, a one-way clutch 120, a first drive gear 121, and a cam sprocket 122 are arranged in order from left to right. Are located. The one-way clutch 120 is provided with a starting gear 120a. The starting gear 120a is connected to the driving gear 125a of the starting cell motor 125 via the idle gear 124.

Next, referring to FIG. 2, with respect to a direction along an imaginary line connecting the axis of the crankshaft 28 and the axis of the secondary sheave shaft 47, the crankshaft 28, the sensor shaft 129, and the starting The positional relationship of the cell motor 125 will be described. First, the lancer shaft 129 is located closer to the secondary sheave shaft 47 than the crankshaft 28. The starting cell motor 125 is disposed further on the secondary sheave shaft 47 side than the balancer shaft 129. However, the starting cell motor 125 is disposed closer to the crankshaft 28 than the secondary sheave shaft 47 is. The starting cell motor 125 is arranged inside the outline of the transmission case 45 in a side view. As shown in FIG. 5, the drive gear 125a of the starting cell motor 125 extends in parallel with the crankshaft 28, and is disposed inside the engine with respect to the starting cell motor 125.

As shown in FIG. 3, the speed reduction mechanism 18 includes an idle shaft (deceleration shaft) 52 parallel to the secondary sheave shaft 47. The idler shaft 52 is connected with a large reduction gear 75 which is engaged with the primary small reduction gear 74. The small reduction gear 74 is rotatably mounted on the secondary sheave shaft 47. The secondary reduction small gear 76 is further integrally formed with the idle shaft 52. The drive shaft 48 is integrally formed with a large reduction gear 77 that meshes with the small reduction gear 76.

The right end of the idle shaft 52 is supported on the left side of the second case 41 via a bearing 91. The left end of the idle shaft 52 is rotatably supported by the left side of the first case 40.

[0081] The drive shaft 48 is arranged in parallel with the idle shaft 52. Therefore, the drive shaft 48 is configured as a separate shaft from the secondary sheave shaft 47. The right end of the drive shaft 48 is supported by the left part of the second case 41 via a bearing 92. The left part of the drive shaft 48 is supported by the left part of the first case 40 via a bearing 93. A sprocket 49 is connected to the left end of the drive shaft 48. The sprocket 49 is connected to a driven sprocket 51 (see FIG. 1) of the rear wheel 7 via a chain 50. A kick shaft 110 extending parallel to the drive shaft 48 is provided below the drive shaft 48 (see FIG. 1). 2).

As shown in FIG. 6, the axis C of the crankshaft 28 is shifted from the center line A of the cylinder 19b (so-called bore center axis) in a side view. In FIG. 6, reference numeral A1 indicates the center line of the cylinder 19b when intersecting with the axis C of the crank shaft 28. That is, the symbol A1 indicates the center line of the cylinder 19b when there is no deviation between the axis C of the crankshaft 28 and the center line of the cylinder 19b. In the present embodiment, the axis C of the crankshaft 28 also offsets the center line A force of the cylinder 19b upward (more specifically, obliquely rearward and upward). In other words, the cylinder 19b is offset downward (more specifically, inclined downward and forward) from the axis C of the crankshaft 28.

[0083] Thereby, a relatively large space can be secured in the upper part of the engine unit 2 or above the engine unit 2. That is, in a side view (see FIG. 2), the center line A of the cylinder 19b is located above an imaginary line connecting the axis of the primary sheave 55 (that is, the right end portion of the crankshaft 28) and the secondary sheave axis 47. A relatively large space can be secured at a higher position. Therefore, it is possible to efficiently arrange the engine auxiliary equipment (such as the lancer weight 129a) and the intake system components 154 in the space. Auxiliary equipment that transmits power to or is transmitted from the crankshaft 28 and whose axial length is longer than the radial length (e.g., balancer, starter motor, separate power generation Machine, drive assist motor, etc.) can be efficiently arranged.

[0084] Further, since the crankshaft 28 is offset, the sliding resistance of the piston 26 can be reduced. Therefore, according to the present embodiment, it is possible to efficiently arrange the devices while minimizing the influence of the friction in the engine.

Here, it is preferable to devise a layout of the intake system component 154. For example, in the engine unit 2, on the side (left side) opposite to the side where the automatic transmission 16 is provided, a large extra space is formed by the absence of the automatic transmission 16. Therefore, at least a part of the suction system component 154 may be arranged in the extra space to avoid interference with the automatic transmission 16.

[0086] In order to reduce the longitudinal length of the engine unit 2, the secondary sheave shaft 47 is pushed. It may be arranged above the axis of the primary sheave 55. In this case, in order to arrange the intake system component 154 above the engine unit 2, it is preferable to arrange the intake system component 154 so as to avoid the secondary sheave 56. By arranging the secondary sheave 56 above the engine unit 2, extra space can be secured in the lower part of the engine unit 2. Therefore, it is possible to secure an extra space around the drive shaft 48, and it is possible to increase the degree of freedom in the layout of the drive shaft 48. As a result, for example, it becomes possible to arrange the drive shaft 48 close to the pivot shaft 100 (see FIG. 1).

[0087] By arranging intake system component 154 above engine unit 2, it is possible to improve the occupant's ability to get on and off motorcycle 1 as compared to the case where intake system component 154 is arranged on the side of the engine unit. it can.

[0088] At least a part of the intake system component 154 may be arranged so as to overlap with the secondary sheave 56 in a side view. With such an arrangement, the intake system component 154 can be arranged above the engine unit 2 while securing a sufficient loading space.

By the way, in a straddle-type vehicle such as a motorcycle that transmits driving force from a drive shaft 48 to a rear wheel 7 via a transmission member such as a chain 50, a transmission belt, and a drive shaft, It is difficult to increase the distance between the drive shaft 48 and the rear wheel 7. Therefore, the position of the drive shaft 48 with respect to the vehicle body is restricted to some extent. In contrast, the installation positions of the secondary sheave shaft 47 and the idle shaft 52 of the reduction mechanism 18 can be determined relatively freely. Therefore, in the present engine unit 2, the secondary sheave shaft 47 is provided separately from the drive shaft 48, and the positions of the secondary sheave shaft 47 and the idle shaft 52 are devised to obtain the following effects.

That is, in the present engine unit 2, since the secondary sheave shaft 47 and the drive shaft 48 are separate axes, the layout of the secondary sheave shaft 47 can be freely changed without being restricted by the drive shaft 48. It is. By arranging the secondary sheave shaft 47 above the drive shaft 48, the size of the lower portion of the engine unit 2 can be reduced, and a relatively large space can be secured below the engine unit 2. Become . Also, as shown in FIG. 2, an imaginary line connecting the drive shaft 48 and the secondary sheave shaft 47 Since the idle shaft 52 is arranged on the front side (the side of the primary sheave 55), the rear part of the engine unit 2 can be downsized, and a relatively large space can be provided behind the engine unit 2. Can be secured. Furthermore, since the drive shaft 48 is arranged inside the outline of the transmission case 45 in a side view, the drive shaft 48 and the speed reducer 18 can be efficiently arranged in the engine unit 2. Become.

[0091] As shown in FIG. 3, in the present engine unit 2, the cam chain chamber 19a and the automatic transmission 16 were arranged on opposite sides of the cylinder 19b. As a result, compared to the case where the cam chain chamber 19a and the automatic transmission 16 are arranged on the same side, the configuration and layout of the components in the engine unit 2 can be simplified, and the timing chain 34 The operation failure of the automatic transmission 16 resulting from the above operation can be prevented. Further, the crankshaft 28 (that is, the primary sheave shaft) fitted into the primary sheave 55 can be shortened. Therefore, the shaft rigidity of the crankshaft 28 can be increased, so that the primary sheave 55 can be supported without supporting the tip of the crankshaft 28 with a bearing or the like, and the primary sheave 55 is cantilevered. It becomes possible.

As shown in FIG. 2, the starting cell motor 125 is disposed above the engine unit 2. For this reason, it is assumed that water and the like are also splashed on the ground force while the motorcycle 1 is running, and there is little possibility that the water or the like will be applied to the starter motor 125.

In this embodiment, as shown in FIG. 5, only one idle gear 124 is interposed between the starting gear 120a and the driving gear 125a of the starting cell motor 125. Needless to say, two or three or more idle gears may be interposed, with only one idle gear 124 being used.

In the present embodiment, as shown in FIG. 3, the reduction gear mechanism 18 includes a primary-side reduction small gear 74 provided on the secondary sheave shaft 47 and a primary-side reduction large gear provided on the idle shaft 52. 75, a small secondary reduction gear 76 provided on the idle shaft 52, and a large secondary reduction gear 77 provided on the drive shaft 48. However, the reduction mechanism is not limited to the reduction gear mechanism 18 having the above configuration. For example, in the reduction gear mechanism 18, the idle shaft 52 and the primary-side large reduction gear 75 are omitted, and the large reduction gear 77 provided on the drive shaft 48 and the small reduction gear 74 provided on the secondary sheave shaft 47 are replaced. Interlock You may do so.

[0095] According to the motorcycle 1, the rear arm 8 can be lengthened, so that steering stability can be improved. Further, the pivot shaft 100 can be positioned below the axis of the secondary sheave shaft 47. Further, the drive shaft 48 and the pivot shaft 100 can be brought close to each other. Therefore, when the rear arm 8 swings around the pivot shaft 100, the slack of the chain 50 wound around the drive shaft 48 can be reduced. Therefore, the transmission efficiency of the driving force to the rear wheel 7 can be improved, and the generation of noise due to the slack of the chain 50 can be suppressed.

In the above embodiment, the driving force transmitting member that transmits the driving force of the drive shaft 48 is the chain 50. However, the driving force transmission member is not limited to the chain 50, and may be a transmission belt or a drive shaft. Even when a drive shaft or the like is used as the transmission member, almost the same effect can be obtained because the distance between the drive shaft 48 and the pivot shaft 100 is short. That is, when the rear arm 8 swings around the pivot shaft 100, it is possible to suppress a decrease in the transmission efficiency of the driving force.

[0097] As described above, the pivot shaft 100 is preferably provided near the rear of the drive shaft 48. It should be noted that the degree of “near” is not particularly limited, but it is particularly preferable that the degree is, for example, within the radius of the secondary sheave 56, which is desired to be within the diameter of the secondary sheave 56.

Industrial applicability

[0098] As described above, the present invention is useful for a straddle-type vehicle engine and a straddle-type vehicle such as a motorcycle.

Claims

The scope of the claims

[1] a cylinder block having a cylinder formed therein;

A piston provided in the cylinder and reciprocating in the cylinder; and a crankshaft rotating in accordance with the reciprocating movement of the piston, wherein the axial center of the crankshaft as viewed in the axial direction of the crankshaft is above the center line of the cylinder. And the crankshaft shifted to

An auxiliary machine that is disposed above the crankshaft when viewed from the axial direction of the crankshaft and transmits power to the crankshaft or transmits the crankshaft power;

A drive shaft that outputs rotational driving force,

A primary sheave that rotates according to the rotation of the crankshaft, a secondary sheave directly or indirectly connected to the drive shaft, and a transmission belt wound around the primary sheave and the secondary sheave. An automatic transmission having: and an engine for a straddle-type vehicle comprising:

2. The saddle according to claim 1, wherein the auxiliary device is disposed above an imaginary line connecting a center of the primary sheave and a center of the secondary sheave when viewed from an axial direction of the crankshaft. Engine for riding type vehicles.

3. The straddle-type vehicle engine according to claim 1, wherein the auxiliary device also has a balancer force.

[4] a cylinder head connected to the cylinder block,

An intake or exhaust valve provided on the cylinder head,

A cam mechanism provided in the cylinder head for opening and closing the valve; and a transmission member for transmitting a rotational driving force of the crankshaft to the cam mechanism. The cylinder block accommodates the transmission member. The engine for a straddle-type vehicle according to claim 1, wherein a transmission member housing chamber is defined, and wherein the cylinder is located between the transmission member housing chamber and the automatic transmission in an axial direction of the crankshaft. .

5. The straddle-type vehicle engine according to claim 1, wherein the primary sheave is cantilevered by the crankshaft.

[6] a crankcase that houses at least the crankshaft;

An intake system component directly or indirectly connected to the cylinder head, wherein at least a part of the intake system component is the cylinder block or the crankcase. 2. The engine for a saddle-ride type vehicle according to claim 1, wherein the engine is disposed above the engine.

[7] an intake system component directly or indirectly connected to the cylinder head,

And a crankcase accommodating at least the crankshaft,

The cylinder block and the crankcase constitute an engine body, the crankshaft extends in the left-right direction,

The automatic transmission is disposed on the left or right side of the engine main body, or on one side, the secondary sheave is disposed above the primary sheave, and the intake system component is disposed above the engine main body. The straddle-type vehicle engine according to claim 1, wherein the engine is disposed on a side opposite to a side on which the automatic transmission is provided in a left-right direction.

8. The straddle-type vehicle engine according to claim 1, further comprising a secondary sheave shaft formed separately from the drive shaft and fitted into the secondary sheave.

[9] a transmission case accommodating the automatic transmission;

A speed reduction mechanism having an idle shaft extending in the left-right direction, the speed reduction mechanism being coupled to the secondary sheave shaft and the drive shaft;

The crankshaft extends in the left-right direction,

The secondary sheave shaft is disposed above the drive shaft,

The idle shaft is disposed on the primary sheave side with respect to an imaginary line connecting the axis of the drive shaft and the axis of the secondary sheave shaft in a side view,

9. The straddle-type vehicle engine according to claim 8, wherein the drive shaft is disposed inside a contour of the transmission case in a side view.

[10] A straddle-type vehicle comprising the saddle-ride type vehicle engine according to claim 1.

[11] A head pipe, a front frame that also extends diagonally downward and rearward with the head pipe force, and a rear frame that extends diagonally upward and rearward from the front frame, wherein the drive shaft is located rearward of the crankshaft. A vehicle body that supports the saddle-ride type vehicle engine in a posture such that it is positioned,

11. The straddle-type vehicle according to claim 10, wherein the cylinder block is supported by being suspended from the front frame.

[12] a vehicle main body that supports the saddle-ride type vehicle engine in a posture such that the drive shaft is located rearward of the crankshaft;

A rear arm that is swingably supported by the vehicle body and supports a rear wheel; a driving force transmitting member that extends in the front-rear direction along the rear arm and transmits driving force from the drive shaft to the rear wheel;

11. The straddle-type vehicle according to claim 10, comprising:

13. The straddle-type vehicle according to claim 12, wherein a support point of the lear arm in the vehicle body is located behind the saddle-ride type vehicle engine in a side view.

14. The straddle-type vehicle according to claim 13, wherein a support point of the lear arm in the vehicle body is located below an axis of the secondary sheave.

15. The straddle-type vehicle according to claim 13, wherein a support point of the lear arm in the vehicle body is located near the rear of the drive shaft.