PH12013000205B1 - Air cooled oil cooler mounting structure for internal combustion engine - Google Patents

Abstract

To provide an air-cooled oil cooler mounting structure of an internal combustion engine, in which an oil cooling effect can be considerably expected, which is assembled to the internal combustion engine without requiring piping of oil pipes, and which is superior in assemblability with less number of parts. In an air-cooled oil cooler mounting structure for an internal combustion engine which is installed in a vehicle and in which a crankcase cover covers an outside of a crankcase in an axial direction, the crankcase rotatably journaling a crankshaft oriented in a vehicle width direction, an oil cooler unit in which an oil introduction passage and an oil lead-out passage are provided integrally with an air-cooled oil cooler is mounted to a front portion of the crankcase cover with the oil introduction passage and the oil lead-out passage respectively communicating with an oil upstream side passage and an oil downstream passage which are formed in the crankcase cover.

Description

AIR-COOLED OIL COOLER MOUNTING STRUCTURE FOR INTERNAL oo po

COMBUSTION ENGINE EE Tint

A - 1 25 © [Technical Field] | Nn Lap

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USE ts. . : . Min. wd

The present invention relates to an air-cooled of cooler i mounting structure for an internal combustion engine installed in a vehicle. = [Background Art] - ]

An air-cooled oil cooler for an internal combustion engine installed in a vehicle is mounted to a place against which travelling air outside the internal combustion engine strikes directly. : SE :

In a Patent Literature 1, an air-cooled oil cooler is mounted to a down frame which extends downward frem a head pipe in a vehicle body frame of a motorcycle. = = /. = ‘ a [Citation List] Eh ai . “O Te [Patent Literature] ND

Cc [Patent Literature 1] JP-A No. 2010-196564

The air-cooled oil cooler disclosed in the Patent

Literature 1 is mounted to the down frame in front of the © 25 internal combustion engine, so that the travelling air strikes directly against the cooler without being influenced by heat of the internal combustion engine and an oil cooling effect can be expected by air cooling. :

- : ch 3 [Summary of Invention] 7 [Technical Problem] oo - : os z

However, the air-cooled oil cooler is separated from the io internal combustion engine, so that an oil introducing pipe : ~ © introducing oil from the internal combustion engine and an oil on lead-out pipe returning the oil to the internal combustion engine - are separately required, and the internal combustion engine and = 0 the air-cooled oil cooler must be connate. Cd

Accordingly, in addition to the work for mounting the air- cooled oil cooler to the down frame, the work for connecting the 0il introducing pipe and the oil lead-out pipe is required, the number of parts is increased, and it takes a lot of time and b> labor to carry out the assembling work.

Moreover, there is a situation where a different member (Eor example, a radiator) is provided at the down frame, thus presenting a case where a space for mounting the air-cooled oil cooler cannot be obtained, and another mounting position is required to be considered.

The present invention has been made in light of such a point, and an object of the present invention is to provide an air-cooled oil cooler mounting structure of an internal combustion engine, in which an oil cooling effect can be considerably expected, which is assembled to the internal combustion engine without requiring piping of oil pipes, and ,

- which 1s superior in assemblability with less number -of parts. | - [Solution to Problem] | -® bed =

To attain the above-mentioned object, an aspect of the oe invention described in claim 1 is that, nN in an air-cooled oil cooler mounting structure for an | - internal combustion engine which is installed in a vehicle and in which a crankcase cover (50) covers an outside of a crankcase > 0 (11) in an axial direction, the crankcase (11) rotatably co journaling a crankshaft (20) oriented in a vehicle width direction, an oil cooler unit (70) in which an oil introduction passage (751) and an oil lead-out passage (76e) are provided integrally with an air-cooled oil cooler (71) is mounted to a

P ~ front portion of the crankcase cover (50) with the oil introduction passage (75i) and the oil lead-out passage (76e) respectively communicating with an oil upstream side passage (58) and an oil downstream side passage (59) which are formed in the crankcase cover (50).

An aspect of the invention described in claim 2 is that, BN in the air-cooled 0il cooler mounting structure of the ~ internal combustion engine according to claim 1, : oo the oil cooler unit (70) is mounted to the front portion of ) the crankcase cover (50) in such a manner that a cooling fin (73) provided at the air-cooled oil cooler (71) assumes a posture facing in a vehicle body forward direction.

- An aspect of the invention described in claim 3 is that, 7 po in the air-cooled oil cooler mounting structure of the | = internal combustion engine according to claim 1 or 2, J the crankcase cover. (50) 1s formed, at an outer peripheral o edge portion of a cover sidewall (51), with a mating surface with - respect to the crankcase (11); and | _ the air-cooled oil cooler (71) is arranged inside in the - vehicle width direction relative to a bulged end of a bulged wall = (52) in front of the bulged wall (52) of the cover sidewall (51), - ° bulging outside in the vehicle width direction.

An aspect of the invention described in claim 4 is that, in the air-cooled oil cooler mounting structure of the internal combustion engine according to claim 3, 5 a front outside surface (51s) of the cover sidewall (51) in front of the bulged wall (52) and a front surface (52s) of the bulged wall (52) are crossed at a substantially right angle to form a corner portion (57) which is notched into an L-shape; and the air-cooled oil cooler (71) is arranged at the corner oo portion (57) in front of the bulged portion (52) of the cover sidewall (51). | i

An aspect of the invention described in claim 5 is that, in the air-cooled oil cooler mounting structure of the internal combustion engine according to claim 4, the front surface (52s) of the bulged wall (52) faces in an obliquely upward direction and inclines.

. | An aspect of the invention described in claim 6 is that, “ pn in the air-cooled oil cooler mounting structure of the = internal combustion engine according ‘to claim 4 or 5, | = ~ mounting boss portions (55, 56) are protrusively formed at | = the front surface (52s) of the bulged wall (52) or the front = outside surface (51s) of the cover sidewall (51) and provided i Co with the oil upstream side passage (58) and the oil downstream - side passage (59); Co = 0 unit mounting portions (75a, 76a) which are fixed to the > mounting boss portions (55, 56) of the bulged wall (52) are provided with the oil introduction passage (75i) and the oil lead-out passage (76e) and formed integrally with the oil cooler unit (70); the unit mounting portions (75a, 76a) of the oil cooler > unit (70) are fixed to the mounting boss portions of the crankcase cover (50), whereby the oil introduction passage (75i) and the oil lead-out passage (76e) are allowed to respectively communicate with the oil upstream side passage (58) and the oil downstream side passage (59), and the oil cooler unit (70) is mounted to the crankcase cover (50).

An aspect of the invention described in claim 7 is that, in the air-cooled oil cooler mounting structure of the internal combustion engine according to claim 6, the oil cooler unit (70) is fixed to the mounting boss portions (55, 56) of the crankcase cover (50) with the air-cooled oil cooler (71) being located outside in the vehicle width direction, and with the unit mounting portions (75a, 76a) being 5 Co

- located inside in the vehicle width direction and along the front 7 on outside surface (51s) of the cover sidewall (51). | = fir

An aspect of the invention described in claim 8 is that, - ox in the air-cooled oil cooler mounting structure of the - internal combustion engine according to any one of claims 1 to 7, - at least a front side of the air-cooled oil cooler (71) and - an outside of the air-cooled oil cooler (71) in the vehicle width | > direction are covered with a breathable protector (80). : An aspect of the invention described in claim 9 is that, in the air-cooled oil cooler mounting structure of the internal combustion engine according to claim 8, the protector (80) is co-fastened, together with the oil

P cooler unit (70), to the crankcase cover (50) and mounted to the crankcase cover (50). [Advantageous Effects of Invention]

According to the air-cooled oil cooler mounting structure - of the internal combustion engine which is described in claim 1, in the air-cooled oil cooler mounting structure of the internal - combustion engine installed in the vehicle, in which the crankcase cover (50) covers the outside of the crankcase (11) in the axial direction, the crankcase (11) rotatably journaling the crankshaft (20) oriented in the vehicle width direction, the oil cooler unit (70) in which the oil introduction passage (751) and : the oil lead-out passage (76e) are provided integrally with the air-cooled oil cooler (71) is mounted to the front portion of the

- crankcase cover (50) with the oil introduction passage (751i) and 7 ot the oil lead-out passage (76¢e) respectively communicating with = the oil upstream side passage (58) and the oil downstream side = passage (59) which are formed in the crankcase cover (50), so o that traveling air strikes directly against the air-cooled oil ~ cooler (71) mounted to the front portion of the crankcase cover . (50) in the vehicle width direction of the crankcase (11) of the | - internal combustion engine (10) and the air-cooled oil cooler = (71) is separated from a heat source of the internal combustion oO

He engine (10) and, thus, the oil cooling effect is considerably X expected, the air-cooled oil cooler (71) is assembled to the crankcase cover (50) as the oil cooler unit (70), without requiring the piping of external oil pipes, assembling work is made more easily with the less number of parts, and the air- 13 cooled oil cooler (71) is superior in assemblability.

According to the air-cooled oil cooler mounting structure of the internal combustion engine which is described in claim 2, the oil cooler unit (70) is mounted to the front portion of the ‘crankcase cover (50) in such a manner that the cooling fin (73) provided at the air-cooled oil cooler (71) assumes a posture facing in the vehicle forward direction, so that the traveling air from the vehicle body forward direction strikes directly . against the cooling fin (73), thus being capable of effectively cooling oil which circulates in the air-cooled oil cooler (71).

According to the air-cooled oil cooler mounting structure of the internal combustion engine which is described in claim 3,

- the crankcase cover (50) is formed, at the outer peripheral edge 7 po portion of the cover sidewall (51), with the mating surface with = respect to the crankcase (11), and the air-cooled oil cooler (71) pi is arranged inside in the vehicle width direction relative to the » bulged end of the bulged wall in front of the bulged wall (52) of’ iy the cover sidewall (51), bulging outside in the vehicle width _ direction, so that the air-cooled oil cooler (71) is mounted by _ using a dead space in front of the bulged wall (52) of the on ] crankcase cover (50), and the bulged wall (52) that entirely | & covers the rear portion of the air-cooled oil cooler (71) in the vehicle width direction can protect the air-cooled oil cooler (71) from the rearward direction.

According to the air-cooled oil cooler mounting structure 2 of the internal combustion engine which is described in claim 4, the front outside surface (51s) of the cover sidewall (51) in front of the bulged wall (52) and the front surface (52s) of the bulged wall (52) are crossed at the substantially right angle to form the corner portion (57) which is notched into an L-shape; and the air-cooled oil cooler (71) is arranged at the corner portion (57) in front of the bulged portion (52) of the cover sidewall (51), so that the air-cooled oil cooler (71) can be compactly housed in the corner portion (57) which becomes the dead space in front of the bulged wall (52) of the crankcase cover (50), thus making it possible to improve the degree of J freedom for the arranging layout in instruments.

According to the air-cooled oil cooler mounting structure

- of the internal combustion engine which is described in claim 5, ® pe the front surface (52s) of the bulged wall (52) faces in the CE obliquely upward direction and inclines, so that the traveling oo r air passing through the air-cooled oil cooler (71) then smoothly 0 passes-through along the inclined surface of the front surface : - . (52s) of the bulged wall (52), thus making it possible to effectively cool the oil. -

Moreover, the bulged wall (52) defends the downside of the i air-cooled oil cooler (71) as well as the rear side of the air- - 0 cooled oil cooler (71) and can protect the air-cooled oil cooler (71) from jumping stones or the like as possible.

According to the air-cooled oil cooler mounting structure of the internal combustion engine which is described in claim 6, the unit mounting portions (75a, 76a) of the oil cooler unit (70) are fixed to the mounting boss portions (55, 56) of the crankcase cover (50), whereby the oil introduction passage (751i) and the : 0il lead-out passage (76e) are allowed to respectively communicate with the oil upstream side passage (58) and the oil downstream side passage (59), and the oil cooler unit (70) is mounted to the crankcase cover (50), thus making piping of external oil pipes unnecessary, reducing the number of parts, and making the assembling work considerably easy. J

According to the air-cooled oil cooler mounting structure : of the internal combustion engine which is described in claim 7, the unit mounting portions (75a, 76a) are located inside in the vehicle width direction and along the front outside surface (51s)

: of the cover sidewall (51), whereby the oil passages (58, 59) in > . the crankcase cover (50) can be made short, and the air-cooled = oll cooler (71) is located outside in the vehicle width direction, o whereby the air-cooled oil cooler (71) can be effectively exposed i. to the traveling air, thus making it possible to improve the ol cooling efficiency of the oil. 0

Loa

According to the air-cooled oil cooler mounting structure i of the internal combustion engine which is described in claim 8, a at least the front side of the air-cooled oil cooler (71) and the outside of the air-cooled oil cooler (71) in the vehicle width direction are covered with the breathable protector (80), so that it is possible to protect, by the protector (80), the air-cooled oil cooler 71 from external force, without detracting the cooling

P effect of the air-cooled oil cooler (71) that is exerted by the traveling air.

According to the air-cooled oil cooler mounting structure of the internal combustion engine which is described in claim 9, the protector (80) is co-fastened, together with the oil cooler unit (70), to the crankcase cover (50) and mounted to the crankcase cover (50), so that the assembling work is made easier / with the less number of parts. | / [Brief Description of Drawings] [Fig. 1] Fig. 1 is a right side view showing a motorcycle ~ equipped with an internal combustion engine according to an embodiment of the present invention.

- [Fig. 2] Fig. 2 is a right side view of the internal > ps combustion engine. | | | : & [Fig. 3] Fig. 3 is a sectional view (a sectional view taken = along line III-III of Fig. 2) of the internal combustion engine. po (Fig. 4] Fig. 4 is an exploded side view of a right ol crankcase cover, an oil cooler unit, and a protector. -

Cd [Fig. 5] Fig. 5 is a front view of the oil cooler unit. I” [Fig. 6] Fig. 6 is a perspective view of the protector. | . 0 [Fig. 7] Fig. 7 is a side view showing a state where the > 0il cooler unit and the protector are installed to the right crankcase cover. [Fig. 8] Fig. 8 is a rear view in the same state. [Fig. 9] Fig. 9 is a front view in the same state. [Fig. 10] Fig. 10 is a plan view in the same state. > [Fig. 11] Fig. 11 is a side view showing a state where a 0il cooler unit and a protector are installed to a right crankcase cover in another embodiment. [Description of Embodiments]

Hereinafter, an embodiment of the present invention will be described based on Figs. 1-10.

Fig. 1 is an entire side view of a motorcycle 1 equipped with an internal combustion engine 10 according to this embodiment. oo

A vehicle body frame 2 of the motorcycle 1 includes a pair of right and left main frames 2b, 2b which extend rearward from a head pipe 2a and further bends downward to form steep slope

- portions 2ba, 2ba, lower portions of which are forward bent in an 7

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L-shape and extend to a lower end portion. *

Moreover, a pair of right and left down frames 2c, 2c which = extend downward and obliquely at an acute angle from the head | pe pipe 2a extends substantially parallel to the steep slope = portions 2ba of the main frames 2b when viewed in a side view. | -

Ca

Seat rails 2d, 2d extend rearward from upper portion of the = steep slope portions 2ba, 2ba of the main frames 2b, 2b. Back hy stays 2e, 2e which connect center portions of the seat rails 2d, 2d and lower portions of the steep slope porlLions 2ba, 2ba support the seat rails 2d, 2d. oo

In such a vehicle body frame 2 as described above, on the 5 head pipe 2a, a front fork 3 is pivotally supported, to a lower end of which a front wheel 4 is journaled, a rear fork 5 which is = . journaled at a front end thereof to pivot plates 2f provided at the lower portions of the main frames 2b, 2b extends rearward, to a rear end of which a rear wheel 6 is journaled and, between the year portion of the rear fork 5 and the center portions of the seat rails 2d, 2d, a rear cushion is interposed.

A fuel tank 8 is disposed between the main frames 2b, 2b.

In rear of the fuel tank 8, a seat 9 is supported by the seat rails 2d, 2d.

The internal combustion engine 10 which is installed in the vehicle body frame 2 is a SOHC type, single-cylinder, four-stroke : internal combustion engine and suspended with respect to the .

to (Ts - vehicle body with a crankshaft 20 being oriented in a vehicle > body width direction and with a cylinder being slightly forward - inclined and raised up. : oo | go - A crankcase 11 which rotatably journals the crankshaft 20 g of the internal combustion engine 10 has a structure in which a oo transmission chamber 11M housing a transmission 40 is formed in - rear of a crank chamber 11C in which the crankshaft 20 is | & arranged (refer to Fig. 3) and downward of the crank chamber 11C, - . a bottom wall is slightly bulged downward to integrally form an oil sump 11P accumulating oil (refer to Figs. 2 and 3).

Referring to Figs. 2 and 3, on the crank chamber 11C of the crankcase 11, a cylinder block 12 having one cylinder 12a is Co lapped, on the cylinder block 12, a cylinder head 13 is lapped through a gasket, the cylinder block 12 and the cylinder head 13 are fastened integrally by a stud bolt 15, and a cylinder head cover 14 covers the upward of the cylinder head 13.

The cylinder block 12, the cylinder head 13 and the : cylinder head cover 14, lapped on the crankcase 11, extend upward in a posture slightly inclined forward from the crankcase 11 (refer Fig. 1 and 2).

An intake pipe 101 extends from the cylinder head 13 of the internal combustion engine 10, installed in the vehicle body : frame, which is slightly inclined forward and raised up in this manner. The intake pipe 101 is connected, via a throttle body 102, to an air cleaner 103 which is arranged in a space surrounded by

. the main frames 2b, the seat rails 2d, and the back stay 2e in a | 2 side view (refer to Fig. 1). | - ; Co

Moreover, an exhaust pipe 105 which extends forward from | = ’ the cylinder head 13 is bent downward, further bent rearward, ~ made close to the rear and right sides of the crankcase 11 along | - an undersurface of the crankcase 11, and connected to a muffler MV 106 that is arranged on the right side of the rear wheel 6. = od : Se

Co. : .

The crankcase 11 which is joined with the lower portion of the cylinder block 12 is configured such that a left crankcase 11L and a right crankcase 11R which constitute a pair of cases including a cylinder axis (a center axis of the cylinder 12a) and divided into left and right section on a plane perpendicular to the crankshaft 20 are put together at mating surfaces thereof and joined by a bolt (refer to Fig. 3).

The crankshaft 20 which is oriented a left and right ~~ direction and rotatably journaled to the left and right crankcases 11L, 11R is configured by connecting left and right crankshaft bodies 20L, 20R with a crankpin 21 to make them integral (refer to Fig. 3).

Annular bearing bushes 22, 22 are buried in bearing hole outer peripheries of mutually opposed bearing walls 11Lw, 11Rw of the left and right crankcases 11L, 11R to which the crankshaft 20 is journaled. The left and right crankshaft bodies 20L, 20R of the crankshaft 20 are journaled to the inner peripheries of the

- bearing bushes 22, 22 through metal bearings 23, 23. | - = iy

On the other hand, as shown in Fig. 3, the lower portion of the cylinder 12a of the cylinder block 12 is fitted in a circular . opening which is formed above the crank chamber 11C by combining nN the left and right crankcases 11L, 11R, and a piston 16 is , reciprocatingly slidably fitted in a cylinder bore 12b of the _ cylinder 12a. =

A piston pin 17 is disposed between a pair of pin bosses & which are protrusively provided on a back surface of a piston top portion of the piston 16. By a connecting rod 18 with a small end port ion thereof journaled to the piston pin 17 and a large end portion thereof Journaled to the crankpin 21 of the crankshaft 20, : . the piston 16 and the crankshaft 20 are connected, whereby a > crank mechanism is configured.

Correspondingly to the cylinder 12a, a combustion chamber 13b is formed in the cylinder head 13 so as to be opposed to the piston 16 in a cylinder axial direction. A spark plug 19 is 20 attached to a ceiling wall of the combustion chamber 13b in such a manner that a tip end thereof faces the combustion chamber 13b (refer to Fig. 3).

Referring to Fig. 3, a valve train 60 is a valve train of 25 the SOHC type internal combustion engine in which one camshaft 65 is oriented in the left and right direction and journaled onto the cylinder head 13. Front and rear rocker arms 671i, 67e which are swung by rotation of the camshaft 65 openingly/closingly

. drive an intake valve and an exhaust valve which are not shown. | o

The camshaft 65 is fitted with a driven chain sprocket 68 - at a left axial end portion thereof (refer to Fig. 3). v os | en

On the other hand, a drive chain sprocket 25 is spline- ~ ‘fitted on a left side of a journal portion of the left crankshaft Py body 20L which protrudes in the left direction from the left ” . bearing wall 11Lw of the crankshaft 20. A cam chain 69 is bridged = between the drive chain sprocket 25 and the driven chain sprocket . oe 68 above the drive chain sprocket 25 (refer to Fig. 3). The rotation power of the crankshaft 20 is transmitted, via the cam chain 69, to the rotation of the camshaft 65 with a 1/2 revolution of the crankshaft 20, the rocker arms 671, 67e swing synchronously with the crankshaft 20, and the intake valve and the exhaust valve respectively drive for opening/closing at a required timing.

A nut member 26 positioning and fixing the drive chain sprocket 25, a starter driven gear 27, and an ACG rotor 30R of an

AC generator 30 through a one-way clutch 29 are sequentially fitted on the left crankshaft body 20L protruding in the left direction from the left bearing wall 11Lw of the crankshaft 20, and fastened and fixed, via a washer 31, with a nut member 32 (refer to Fig. 4). oo

An inner stator 30S is fixedly supported by an inner cylinder 49a formed at a left crankcase cover 49 which covers the

AC generator 30 and the like from the left side.

- On the other hand, as shown in Fig. 3, a balancer drive 7 poi gear 35 and a primary drive gear 36 are sequentially fitted on = the right crankshaft body 20R protruding in the right direction 5 from the right bearing wall 11Rw of the crankshaft 20, a filter case 37a of a centrifugal filter 37 is further fitted on the _ right crankshaft body 20R, and they are fastened and fixed, via a -

Lr washer 39w, with a nut member 39n. -

The centrifugal filter 37 is configured such that a right oo 0 side opening of the cup-shaped filter case 37a is covered with a bowl-shaped filter cover 37b and a centrifugal separation chamber 37¢ is formed inside. A communication pipe 38 penetrates through a center of the filter cover 37b coaxially with thc crankshaft 20.

A right crankcase cover 50 covers the right side of the

P right crankcase 22R (refer to Fig. 3). The communication pipe 38 penetrating through the filter cover 37b is press-contacted with an opened end of an oil passage of the right crankcase cover 50 : by a coned disc spring 38s. i

Referring to Fig. 3, a main shaft 41 and countershaft 42 of the transmission 40 are oriented to the left/right direction in rear of the crankshaft 20, parallel to each other, and rotatably : disposed, via bearings 41b, 42b, between the left and right bearing walls 11Lw, 1lRw in the transmission chamber 11M of the crankcase 11. A main gear group 41g journaled to the main shaft 41 and a counter gear group 42g journaled to the countershaft 42 are normally meshed with each other to constitute the transmission 40.

Coa

The countershaft 42 penetrates through the crankcase 11 in J the left direction, and protrudes outside to form an output shaft

Cs An output sprocket 43 is fittingly mounted on a left end of the i. countershaft 42 which protrudes. | -

A drive chain 44 which is wound around the output sprocket 43 is stretched with respect to a driven sprocket on a rear wheel - side, which is not shown, to configure a chain transmission = mechanism, by which power is transmitted to the rear wheel. o

A multiplate friction shift clutch 46 is provided at a right side portion of the main shaft 41 which protrudes in the right direction from the right bearing wall 11Rw.

A clutch outer 460 of the shift clutch 46 is supported, via > a buffer member, on a primary driven gear 45 which is rotatably journaled to the main shaft 41. Between the clutch outer and a : clutch inner 46i integrally fitted with respect to the main shaft 41, a plurality of clutch plates 46c are interposed. By the drive of a compression member 46p, disconnection is performed.

The primary driven gear 45 is meshed with the primary drive gear 36 which is fittingly mounted on the crankshaft 20.

Accordingly, the power of the crankshaft 20 is transmitted to the main shaft 41 of the transmission 40 and interrupted, by the drive of the shift clutch 46.

In front of the crankshaft 20, a balancer shaft 47 is rotatably disposed between the left and right bearing walls 11Lw,

@ . 11Rw (refer to Fig. 2). A balancer driven gear (not shown) is 7 po provided at a right side portion of the balancer shaft 47, which = protrudes in the right direction from the right bearing wall 11Rw, and is meshed with the balancer drive gear 35 fittingly mounted to the crankshaft 20. = a

Incidentally, in rear of the cylinder block 12 which is - slightly inclined forward and protrusively provided from the = crankcase 11, a starter motor 120 is arranged on an upper wall of - the crankcase 11.

The drive of the starter motor 120 is transmitted, via an unshown gear mechanism, to the starter driven gear 27. : The right crankcase cover 50 which is put on the right b> crankcase 11R from the outside covers the centrifugal filter 37 at the right end of the crankshaft 20, the shift clutch 46 at the right end of the main shaft 41, the power transmission gear mechanism with respect to the balancer shaft 47, a power transmission gear mechanism (not shown) with respect to an oil pump 48 below the crankshaft 20, etc., from the right side (refer to Fig. 2).

Referring to Figs. 4 to 10, in the right crankcase cover 50, : an outer peripheral edge of a cover sidewall 51 is bent inside (a 23 side of the right crankcase 11R) to form an outer peripheral edge portion 54 having at an end surface a mating surface 54s with respect to the right crankcase 11R, and a plurality of mounting holes 54h are formed in the outer peripheral edge portion 54.

In the cover sidewall 51, its front, rear, and lower = portions are partially left and a major part of its substantially - center is largely bulged outside in the vehicle width direction to form a bulged wall 52, and further a center portion (portion ” opposed to the shift clutch 46) of the bulged wall 52 is formed | - . Coun with a circular-shaped bulge portion 53 bulged into a circular- . shape. >

A front surface 52s of the bulged wall 52 of the right a crankcase cover 50 faces obliquely upward and inclines. A front ~ outside surface 51s of the cover sidewall 51 in front of the bulged wall 52 and a front surface 52s of the bulged wall 52 are crossed at a substantially right angle to form a corner portion is 57 which is notched into an L-shape (refer to Figs. 4 and 7). ~The inclining front surface 52s of the bulged wall 52 is formed with a pair of a lower mounting boss portion 55 and an upper mounting boss portion 56 which protrudes obliquely upward.

The lower mounting boss portion 55 and the upper mounting boss portion 56 exhibit an elliptical shape with its major axis being oriented obliquely vertically and project along the front outside surface 51s of the cover sidewall 51. oo

An oil upstream side passage 58 which penetrates a center : of the lower mounting boss portion 55 opens in an elliptical shaped end surface of the lower mounting boss portion 56, the end surface being formed with bolt mounting holes 55b, 55b vertically of the opening of the oil upstream side passage 58.

- Similarly, an oil downstream side passage 59 which | = penetrates a center of the upper mounting boss portion 56 opens = food in an elliptical shaped end surface of the upper mounting boss = portion 56, the end surface being formed with bolt mounting holes we 56b, 56b vertically of the opening of the oil downstream side . passage 59. o

The oil upstream side passage 58 extends rearward and - obliquely downward and communicates with a discharge oil passage - of the oil pump 48.

A divergent oil passage 58b which diverges from a midway of the oil upstream side passage 58 leads to the centrifugal filter 37 provided at the right end of the crankshaft 20.

The oil downstream side passage 59 is an oil passage which passes the crankcase 11 and the cylinder block 12 and supplies oil to the valve train 60 of the cylinder head 13.

An oil cooler unit 70 is mounted to the lower mounting boss portion 55 and the upper mounting boss portion 56.

As shown in Figs. 4 and 5, the oil cooler unit 70 is integrated by causing an oil introduction passage 75i and an oil : lead-out passage 76e to be integrally provided at an air-cooled oil cooler 71. :

In the air-cooled oil cooler 71, three communication pipes 72 which are each made by overlapping a pair of plate members in a sandwich shape and has connecting pipes 72i, 72e bulged at both end portions, and is formed into a flat elongated circular-shape : 21 oo

I

- are integrated by taining the connecting pipes 721, Ize. Among ~

Ca the flat communication pipes 72, 72, a cooling fin 73 is | = interposed. | - | Oil which is introduced into three connecting pipes 72i on 0 one side, which are communicated with one another, passes through = the three communication pipes 72, and leads into the three | oo

Co 5 connecting pipes 72e on the other side, which are communicated _ with one another, during which the oil is effectively cooled by = the cooling fin 73 from which heat is removed by traveling air. 5

Referring to Figs. 4 and 5, a unit mounting portion 75a which is fastened to the lower mounting boss portion 55 is formed a integrally with an oil introduction pipe 75 which extends to the three connecting pipes 721 on the one side, which communicates co © ‘with one another.

The unit mounting portion 75a is opposed to an elliptical- shaped end surface of the lower mounting boss portion 55 and : exhibits an elliptical plate shape, on a center of which the oil introduction passage 75i communicating with the oil upstream side passage 58 opens. The oil introduction passage 751 extends perpendicularly from the same opening, is bent at a right angle, forms a passage of the oil introduction pipe 75, and communicates with the three connecting pipes 72i.

Bolt penetrating holes 75b, 75b are formed vertically of the opening of the oil introduction passage 75i in the center of the unit mounting portion .75a.

Similarly, a unit mounting portion 76a which is fastened to

: Ca . the upper mounting boss portion 56 is formed integrally with an | “ oil lead-out pipe 76 which extends to the three connecting pipes - 72e on the one side, which communicate with one another. pot

The unit mounting portion 76a is opposed to an elliptical ~ shaped end surface of the upper mounting boss portion 56 and | ~ : exhibits an elliptical plate shape, on a center of which the oil lead-out passage 76e communicating with the oil downstream side . - passage 59 opens. The oil lead-out passage 76e extends = perpendicularly from the opening, is bent at a right angle, forms = a passage of the oil lead-out pipe 76, and communicates with the three connecting pipes 72e.

Bolt penetration holes 76b, 76b are formed vertically of the opening of the oil lead-out passage 76e in the center of the unit mounting portion 76a.

As shown in Fig. 4, the oil cooler unit 70 in which the oil introduction passage 751i and the oil lead-out passage 76e are : integrally provided at the air-cooled oil cooler 71 as described above is mounted with the air-cooled oil cooler 71 being arranged - outside (right side) and with the unit mounting portions 75a, 76a being arranged inside (left side) and fixed to the lower mounting boss portion 55 and the upper mounting boss portion 56 which are protrusively formed on the front surface 52s of the bulged wall 52 of the right crankcase cover 50 which inclines so as to face obliquely upward.

Incidentally, both of connecting seal-pipes 77, 78 (refer . to Fig. 4) are fitted in the openings of the oil passages which are respectively opposed to the lower mounting boss portion 55

: and the unit mounting portion 75a, and the upper mounting boss = po portion 56 and the unit mounting portion 76a, and respectively = make communication between the oil upstream side passage 58 and = fo the oil introduction passage 751i and between the oil downstream oe side passage 59 and the oil lead-out passage 76e. =

Co;

Accordingly, the oil delivered from the oil pump 48 = diverges from the divergent oil passage 58b diverging from the oo oil upstream side passage 58, the oil which flows into the divergent oil passage 58b on one side is supplied to lubrication EE portions in the crankcase 11 of the crankshaft 20 and the like, 0il which does not diverges into the divergent oil passage on the ~~ other side flows into the air-cooled oil cooler 71 from the oil + upstream side passage 58, is cooled and allowed to flow out to © the oil downstream side passage 59, Flows to the cylinder block 12 and the cylinder head 13, in which temperature rising is large, from the oil downstream side passage 59, and can be used for cooling. , .

The air-cooled oil cooler 71 does not cool all lubricant oils and cools only oils supplied to the cylinder block 12 and the cylinder head 13 which are particularly required to be cooled, and can be therefore made to a compact structure whose capacity - is reduced.

A protector 80 which is formed of a metal mesh is put on the air-cooled oil cooler 71 of the oil cooler unit 70 (refer to

Fig. 4).

; As shown in Fig. 6, the metal mesh of the protector 80 2 includes an outside portion 8la, which almost covers an outside = of flat elongated circular-shaped communication pipe 72 on an i

Le outermost side of the air-cooled oil cooler 71, an inside portion. te 81b, which covers substantially a half of an inside of a o communication pipe 72 on an innermost side, and an outer o peripheral portion 8lc, which connects outer peripheral edges of - the outside portion 8la and inside portion 81b and covers a front . re side (obliquely upper side) and vertical side of the air-cooled @ 0il cooler 71, and opens rearward (obliquely downward) .

A rear edge of the inside portion 81b of the protector 80 is formed with semi-circular shaped notches 81bv, 8lbv which is escapes the- oil introduction pipe 75 and the oil lead-out pipe 76. ’

Mounting pieces 82, 82 which are respectively formed with mounting holes 82b, 82b in a vertical direction of the notches 81bv, 81bv protrude inside at a right angle.

When the oil cooler unit 70 is fastened to the right crankcase cover 50 by a bolt 85, the protector 80 is mounted with the mounting pieces 82 being co-fastened by the bolt 85. :

More specifically, as shown in Fig. 4, the unit mounting portions 75a, 76a which are positioned inside (left side) the air-cooled oil cooler 71 of the oil cooler unit 70 is made to abut from a forward and oblique upward direction on the lower mounting boss portion 55 and the upper mounting boss portion 56 which are protrusively formed on the obliquely upward facing and inclined front surface 52s of the bulged wall 52 of the right

- crankcase cover 50, the protector 80 is put on the air-cooled oil 7 pot cooler 71, the mounting holes 82b, 82b of the upper and lower = mounting pieces 82, 82 at the rear edge of the inside portion 81b o bs of the protector 80 are made aligned with the bolt penetrating x holes 76b, 76b of the unit mounting portions 75a, 76a, and the = bolts 85, 85 are threadedly penetrated through the bolt mount ing - holes 55b, 55b of the lower mounting boss portion 55 and upper - mounting boss portion 56 to co-fasten the oil cooler unit 70 and | = the protector 80 to the right crankcase cover 50. ~

When the oil cooler unit 70 is mounted to the front.surface 52s of the bulged wall 52 of the right crankcase cover 50 in this way, the oil delivered from the oil pump 48 passes through the 0il upstream side passage 58 and the oil introduction passage 751 12 of the oil introduction pipe 75, is introduced into the three connecting pipes 721i with which the air-cooled oil cooler 71 communicates, passes through the three communication pipes 72, leads to the three connecting pipes 72e on the other side which communicate with each other. During which the oil is cooled by the cooling fin 73 and the communication pipe 72 whose heat is Co removed by traveling air, the cooled oil passes through the oil downstream side passage 59 from the oil lead-out passage 76e of the oil lead-out pipe 76 and is supped to the valve train 60. - The oil cooler unit 70 in which the oil introduction passage 751i and the oil lead-out passage 76e are provided integrally with the air-cooled oil cooler 71 is mounted to the oo right crankcase cover 50 with the oil introduction passage 75i

; and the oil lead-out passage 76e being made to respectively ~ communicate with the oil upstream side passage 58 and the oil = downstream side passage 59 which are formed in the mounting boss - ot portions 55, 56 of the right crankcase cover 50, so that the air- © cooled oil cooler 71 is assembled to the right crankcase cover 50 as the oil cooler unit 70, without requiring the piping of - external oil pipes, and assembling work of the air-cooled oil = cooler 71 is very easily carried out with less number of parts | > : Co Lo 0 and superior in assemblability. ft

The state where the oil cooler unit 70 and the protector 80 are mounted to the right crankcase cover 50 in this way is shown in Figs. 7 to 10. oo oo The air-cooled oil cooler 71 of the oil cooler unit 70 is

P arranged at the corner portion 57 becoming a dead space that is notched into an L-shape by crossing the front outside surface 51s of the cover sidewall 51 in front of the bulged wall 52 of the right crankcase cover 50 and the front surface 52s of the bulged wall 52 at the substantially right angle.

As shown in Fig. 9, the air-cooled oil cooler 71 is arranged inside (left side) in the vehicle width direction - relative to a bulged end (a rightmost end of the bulged wall 52) of the bulged wall in front of the bulged wall 52, so that the air-cooled oil cooler 71 is mounted using the dead space in front of the bulged wall 52 of the right crankcase cover 50, and the bulged wall 52 that entirely covers the rear portion of the air- cooled oil cooler 71 in the vehicle width direction can protect

; the air-cooled oil cooler 71 from the rearward direction. ¢

The air-cooled 0il cooler 71 can be compactly housed in the - corner portion 57 which becomes the dead space in front of the bulged wall 52 of the right crankcase cover 50, thus making it on possible to improve the degree of freedom in the arranging layout of instruments. | | on 1,

The air-cooled oil cooler 71 which is mounted onto the 3 obliquely upward facing and inclined front surface 52s of the . bulged wall 52 of the right crankcase cover 50 is present at a pogition for receiving the traveling air from a forward direction, and the cooling fin 73 which is interposed between the communication pipes 72, 72 of the air-cooled oil cooler 71 is mounted in a posture of facing the vehicle body forward direction, so that the traveling air from the vehicle body forward direction strikes directly against the cooling fin 73 and can effectively cool the oil which circulates in the air-cooled oil cooler 71.

Moreover, the front surface 52s of the bulged wall 52 faces in the obliquely upward direction and inclines, so that the traveling air passing through the air-cooled oil cooler 71 then smoothly passes-through along the inclined surface of the front surface 52s of the bulged wall 52, thus making it possible to effectively cool the oil.

Incidentally, the traveling air which enters between the alr-cooled oil cooler 71 and the front outside surface 51s of the cover sidewall 51 can passes outside (right direction) between the lower mounting boss portion 55 and the upper mounting boss

’ portion 56, air accumulation is not produced, and cooling ~ . operation is not prevented. =

Pod 2 | Moreover, the front surface 52s of the bulged wall 52 faces = the obliquely upward direction and inclines, so that the bulged N wall 52 defends the downside of the air-cooled oil cooler 71 as ’ well as the rear side of the air-cooled oil cooler 71 and can oT protect the air-cooled oil cooler 71 from jumping stones or the o

Te like as possible. -

The unit mounting portions 75a, 76a are located along the front outside surface 51s of the cover sidewall 51 inside in the vehicle width direction, whereby the oil upstream side passage 58 5 and the oil downstream side passage 59 in the right crankcase ’ cover 50 can be made short, and the air-cooled oil cooler 71 is located outside in the vehicle width direction, whereby the air- cooled oil cooler 71 can be effectively exposed to the traveling air, thus making it possible to improve the cooling efficiency of the oil.

At least the front side of the air-cooled oil cooler 71 and the outside of the air-cooled oil cooler 71 in the vehicle width direction are covered with the protector 80 of metal mesh that has a breathability, so that it is possible to protect the air- 23 cooled oil cooler 71 from external force, without detracting the cooling effect of the air-cooled oil cooler 71 that is exerted by the traveling air. :

Moreover, the protector 80 is co-fastened together with the

. oil cooler unit 70 and mounted to the right crankcase cover 50, - . fmm so that the assembling work is made easier with the less number = po of parts. . en . frre 5 . : | . LA uo - Incidentally, as the breathable protector, it is ~ conceivable that it is made to a louver structure, aside from the wn 1 metal mesh. _ ] , Am . Lhd } ' Li

An air-cooled oil cooler mounting structure according to oN another embodiment is shown in Fig. 11 and will be explained.

The same reference signs which are applied to the members of the above-mentioned embodiment are applied to the members of this embodiment. . As apparent from comparing the same air-cooled oil cooler mounting structure to the embodiment shown in Fig. 7, mounting boss portions 54b, 54b of two front mounting holes 54h, 54h of an outer peripheral edge portion 54 of the right crankcase cover 50 mounted to the right crankcase 11R protrudes forward relative to the outer peripheral portion 8lc of the protector 80.

Accordingly, all mounting boss portions of the right crankcase cover 50 are not overlapped with the air-cooled oil cooler 71 and the protector 80 when viewed in the side view.

For that reason, when the right crankcase cover 50 is removed from the crankcase 11, the air-cooled oil cooler 71 and the protector 80 do not become obstacles and are not required to be removed from the right crankcase cover 50, and the attaching/detaching work of the right crankcase cover 50 can be :

. performed while leaving the air-cooled oil cooler 71 and the @ protector 80 attached to the right crankcase cover 50, and the - workability is good. [Reference Signs List] | o i. wd 10.. Internal combustion engine | . 11... Crankcase - 11P.. Oil sump - 20.. Crankshaft | : -

© 20L, 20R.. Crankshaft body : 37... Centrifugal filter : 38... Communication pipe 47... Balancer shaft 48.. 011 pump 49.. Left crankcase cover 50.. Right crankcase cover 51... Cover sidewall 51s.. Front outside surface 52... Bulged wall 52s.. Front surface : 53.. Circular-shaped bulge portion 55... Lower mounting boss 56... Upper mounting boss : 57.. Corner portion 58.. Oil upstream side passage 59.. Oil downstream side passage 60.. Valve train 70.. 0il cooler unit -

} 71.. Air-cooled oil cooler @ : 72... Communication pipe } = 73... Cooling fin 75.. 011 introduction pipe ~ 75a... Unit mounting portion ~ 751i... 011 introduction passage | . 76... 0il lead-out pipe - 76a... Unit mounting portion ~ ~ 76e.. 011 lead-out passage 0 ° 77, 178.. Connecting seal-pipe 20... Protector 8la.. Outside portion 81b.. Inside portion . 81lc.. Outer peripheral portion 82.. Mounting piece 85... Bolt

Claims (5)

1. ) 7, a CL Lr Se oo : | - “o Zz fel per PROPERTY ok ~ [Document Name] Claims %, o | TTT % >, BHTHAR -3 £3 3:0p 0

   [Claim 1] “ D oY An air-cooled oil cooler mounft ing structure for an fit internal combustion engine which As installed in a vehicle and - in which a crankcase cover (50) covers an outside of a | ~ crankcase (11) in an axial direction , the crankcase (11) od rotatably journaling a crankshaft (20) oriented in a vehicle width direction, ” wherein an oil cooler unit (70) in which an oil - introduction passage (751) and an oil lead-out passage (76e) are provided integrally with an air-cooled oil cooler (71) is = mounted to a front portion of the crankcase cover (50) with the oil introduction passage (751) and the oil lead:out passage (76e) respectively communicating with an oil upstream side passage (58) and an oil downstream side passage (59) which are formed in the crankcase cover (50); wherein the crankcase cover (50) is formed, at an outer peripheral edge portion of a cover sidewall (51), with a mating surface with respect to the crankcase (11); and } the air-cooled oil cooler (71) is arranged inside in the vehicle width direction relative to a bulged end of a bulged wall (52) in front of the bulged wall (52) of the cover sidewall (51), bulging outside in the vehicle width direction; wherein a front outside surface (51s) of the cover sidewall (51) in front of the bulged wall (52) and a front surface (52s) of the bulged wall (52) are crossed at a substantially right angle to form a corner portion (57) which . 1s notched into an L-shape; and the air-cooled o0il cooler (71) 1s arranged at the corner : portion (57) in front of the bulged portion (52) of the cover sidewall (51); and wherein mounting boss portions (55, 56) are protrusively formed at the front surface (52s) of the bulged wall (52) or —-

   the front outside surface (51s) of the cover sidewall (51) and = provided with the oil upstream side passage (58) and the oil ~ downstream side passage (59); | Co = unit mounting portions (75a, 76a) which are fixed to the jy mounting boss portions (55, 56) of the bulged wall (52) are ~ provided with the oil introduction passage (751) and the oil | ~ lead-out passage (76e) and formed integrally with the oil oo cooler unit (70); 1 the unit mounting portions (75a, 76a) of the oil cooler - unit (70) are fixed to the mounting boss portions of the on crankcase cover (50), whereby the oil introduction passage (751) and the oil lead-out passage (76e) are allowed to respectively communicate with the oil upstream side passage (58) and the oil downstream side passage (59), and the oil cooler unit (70) is mounted to the crankcase cover (50).
2. [Claim 2] : The air-cooled oil cooler mounting structure for an internal combustion engine, according to claim 1, wherein the . oil cooler unit (70) is mounted to the front portion of the crankcase cover (50) in such a manner that a cooling fin (73) provided at the air-cooled oil cooler (71) assumes a posture facing in a vehicle body forward direction.
3. [Claim 3] The air-cooled oil cooler mounting structure for an internal combustion engine, according to claim 1, wherein the front surface (52s) of the bulged wall (52) faces in an - obliquely upward direction and inclines. .
4. [Claim 4] The air-cooled oil cooler mounting structure for an internal combustion engine, according to claim 1, wherein the oil cooler unit (70) is fixed to the mounting boss portions (55, 56) of the crankcase cover (50) with the air-cooled oil cooler (71) being located outside in the vehicle width direction,—~and with the unit. mounting portions-{75a, 76a)

   being located inside in the vehicle width direction and along © the front outside surface (513) of the cover sidewall (51). ~
5. [Claim 5] Bo The air-cooled oil cooler mounting structure for an : internal combustion engine, according to any one of claims 1 : = to 4, wherein at least a front side of the air-cooled oil © cooler (71) and an outside of the air-cooled oil cooler (71) i. in the vehicle width direction are covered with a breathable oon protector (80). , J