JP2000087757A - V-type internal combustion engine for motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chain tensioner lifter on a rear wall of a rear bank while avoiding interference with a transmission case section, without the need of setting a rearward tilting angle of the rear bank to be particularly smaller. SOLUTION: A primary transmitting device and a rear timing-transmitting device are connected to both ends of a crankshaft 15. A side wall 95a of a mission case 95 on the side of the rear timing-transmitting device is offset in a direction from the rear timing-transmitting device toward the primary transmission device. With this arrangement, a chain tensioner lifter 492 can easily be mounted on a rear wall of a rear bank without being interfered with the transmission case section 95.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a V-type internal combustion engine for a motorcycle, and more particularly, to a front part and a rear part which are opened forward and backward about a crankshaft which is arranged in a lateral direction when mounted on a vehicle body frame. A transmission case for housing a transmission is integrally connected to the rear of a crankcase having a bank and housing a crankshaft. The crankshaft has a primary transmission device for transmitting power to the transmission, The front and rear timing transmissions that drive the valve cam shafts of the front and rear banks, respectively, are connected to each other, and a lifter that presses the chain tensioner of the corresponding timing transmission is mounted on the rear wall of each bank. The present invention relates to improvement of a V-type internal combustion engine for a motorcycle.

[0002]

2. Description of the Related Art Such a V-type internal combustion engine for a motorcycle is known as disclosed in, for example, Japanese Patent Application Laid-Open No. 64-83912.

[0003]

In such a conventional V-type internal combustion engine for a motorcycle, a lifter for a chain tensioner mounted on a rear wall of a rear bank and a transmission case portion connected to a rear portion of a crankcase are provided. In order to avoid the interference of the rear bank, the rear bank has a small rearward inclination angle.

[0004] However, in this case, the included angle between the front and rear banks is set to 90 ° or less, or the front tilt angle of the front bank is set to be large according to the decrease in the rear tilt angle of the rear bank. However, both are not desirable in appearance.

[0005] The present invention has been made in view of such circumstances, and without setting the rear inclination angle of the rear bank to a particularly small angle, a chain tensioner lifter is mounted on the rear wall of the rear bank and the transmission case is mounted on the transmission case. It is an object of the present invention to provide a V-type internal combustion engine for a motorcycle, which can be mounted without interference.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a front and rear bank which is opened to the front and rear around a crankshaft which is arranged in a lateral direction when mounted on a body frame. A transmission case for housing a transmission is integrally connected to a rear portion of a crankcase for housing the crankshaft; a primary transmission device for transmitting power to the transmission; A motorcycle having front and rear timing transmissions that respectively drive the valve shaft camshafts of the rear and rear banks, and a lifter that presses a chain tensioner of the corresponding timing transmission on the rear wall of each bank. In the V-type internal combustion engine, the primary transmission and the rear timing transmission are connected to both ends of the crankshaft, and the rear timing transmission side wall of the transmission case is connected to the rear tie. A first feature that it has an offset to the primary transmission side of the ring gear.

According to the first feature, a slight offset between the main body of the crankcase and the transmission case in the left-right direction allows the rear bank of the rear bank to be rearwardly inclined without setting the rear bank of the rear bank at a particularly small angle. The chain tensioner lifter can be mounted on the wall without interference with the transmission case.

In addition to the above-mentioned features, the present invention further comprises a front timing transmission and a rear timing transmission connected to one end of a crankshaft adjacent to each other, and the rear timing transmission is connected to an axial direction of the front timing transmission. The second feature is that it is arranged outside.

According to the second feature, the offset amount between the main body of the crankcase and the transmission case can be minimized, and the internal combustion engine E can be made compact. In addition, the centralized arrangement of the two timing transmissions improves their assemblability and maintainability.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

FIG. 1 is a side view of a motorcycle equipped with the V-type internal combustion engine of the present invention, FIG. 2 is a side view of the internal combustion engine, and FIG.
4 is a sectional view taken along line 3-3 of FIG. 2, FIG. 4 is a sectional view taken along line 4-4 of FIG. 3, FIG. 5 is a sectional view taken along line 5-5 of FIG. 2, and FIG. 7 is a sectional view taken along the line 7-7 in FIG. 2, FIG. 8 is an enlarged view around the front and rear timing transmissions in FIG.
9 is an enlarged view around the transmission of FIG. 3, FIG. 10 is a plan view around the exhaust system of the internal combustion engine, FIG. 11 is a plan view of the cylinder head of the rear bank, and FIG. is there.

In the description, the terms front and rear, left and right are based on the body of a motorcycle. [Overall Configuration of Motorcycle (See FIGS. 1 and 2)] A front fork (neither is shown) for supporting front wheels is steerably connected to the front end of a body frame 1 of the motorcycle M. A rear fork 3 for supporting the rear wheel 2 is vertically swingably connected to a rear portion of the body frame 1, and a rear cushion 7 is interposed between the rear fork 3 and each rear end of the body frame 1. .

A V-type internal combustion engine E having front and rear banks 4 ₁ and 4 ₂ is mounted at an intermediate portion of the body frame 1, and a fuel tank 5 is mounted above the V-type internal combustion engine E. Further, a main seat 6a and a pillion seat 6b are attached to a rear portion of the vehicle body frame 1 so as to be continuous with a rear end of the fuel tank 5.

The chain transmission 10 that connects the output shaft 97 of the transmission 8 connected to the internal combustion engine E and the hub of the rear wheel 2 is disposed on the left side of the rear wheel 2. Starting motor 11
Are arranged in front of and below the crankshaft 15.

The front and rear banks 4 ₁ , 4 of the internal combustion engine E
_In the valley 28 between the _two, front and rear carburetors 12 ₁ and 12 ₂ connected to the corresponding banks are arranged. The front exhaust pipe 13 ₁ and the rear exhaust pipe 13 ₂ connected respectively to the rear of the front bank 4 ₁ in the front and the rear bank 4 _2,
It is connected to the front end of a common exhaust muffler 14 disposed on the opposite side of the chain transmission 10 with respect to the rear wheel 2, that is, on the right side of the rear wheel 2. [Overall Configuration of an internal combustion engine (2, 3, 5, see FIG. 8) the front bank of the internal combustion engine E 4 ₁ and the rear bank 4 ₂
Is 90 ° around the crankshaft 15 arranged in the left-right direction.
Open and placed back and forth. The crankshaft 15 includes a single crank portion 16 having a crank pin 16a, and a pair of left and right journals 17 and 18 adjacent to both ends thereof. The journals 17 and 18 respectively include ball bearings 19 and 20. It is supported by the crankcase 21 through the.

The front and rear banks 4 ₁ , 4 ₂ are respectively provided with cylinder blocks 22 ₁ , 22 for connecting the crankshaft 15 to the front and rear slopes of the upper part of the chevron of the crankcase 21.
₂ and cylinder head 2 joined to their upper ends
3 ₁ , 23 _2, and each cylinder block 22
_A series of water jackets 24 ₁ and 24 ₂ are formed on the cylinder heads ₁ and 22 ₂ and the cylinder heads 23 ₁ and 23 ₂ .

The pistons 26 ₁ and 25 ₂ fitted in the cylinder bores 25 ₁ and 25 ₂ of the cylinder blocks 22 ₁ and 22 ₂ , respectively.
26 ₂ is connected to the crank pin 16a via connecting rods 27 _1, 27 _2. At that time, the connecting rod 27 ₂ of the rear bank 4 _2, the crank on the pin 16a in disposed adjacent to the left of the connecting rod 27 ₁ of the front bank 4 _1, these connecting rods 27 _1, 27 ₂ in the lateral direction of the offset corresponding to the amount S (FIG. 8), the rear bank 4 ₂ of the axis is offset to the left relative to the front bank 4 ₁ axis.

As shown in FIG. 5, at the right end of the crankshaft 15 protruding outward from the right journal 18, the primary transmission connected to the overrunning clutch 53 and the clutch 100 of the starting transmission 94 in order from the inside. Device 54
Are mounted and arranged adjacent to each other. At that time, the overrunning clutch 53
The outer member is spline-coupled to the crankshaft 15 and the starting gear 52 is fixed to the inner member. The drive gear 54a is keyed to the crankshaft 15.

[0019] As shown in FIG. 8, the left end portion protruding outwardly from the left journal 17 of the crankshaft 15, the front for driving the valve operating cam shaft 41 ₁ of the front bank 4 ₁ order from inside drive timing sprocket 42 ₁ of the timing transmission 46 _1, the rear bank 4 ₂ of the valve operating cam shaft 41 ₂
Timing sprocket 42 _{2 of} the rear timing transmission 46 ₂ for driving the motor, and the rotor 3 of the generator 30
1 are mounted and arranged adjacent to each other. At this time, the rotor 31 is keyed to the crankshaft 15. The mounting structure of the _two drive timing sprockets 42 ₁ and 422 will be described later.

A stator 32 of the generator 30 surrounded by the rotor 31 is fixed to an inner wall of a left cover 33 which is joined to a left end surface of the crankcase 21.

A protrusion 35 is provided on the outer peripheral surface of the rotor 31.
A crank position sensor 36 for detecting the rotational position of the crankshaft 15 in cooperation with the projection 35 is fixed to the left end surface of the crankcase 21. The output signal of the crank position sensor 36 is used as a control signal for an ignition device and an input signal for a tachometer.

At the right end of the crankshaft 15 opposite to the generator 30, the starting gear 5 is located adjacent to the right journal 18.
2 is supported via an overrunning clutch 53, and a primary drive gear 5 adjacent to its starting gear 52.
4a is keyed.

With the above configuration, the crankshaft 15
Front and rear timing transmissions 46 ₁ ,
Can be assembled 46 ₂ at once, their assembling property is improved. Front and rear timing transmissions 46
_1, when performing 46 ₂ of maintenance, simply by removing only the generator 30 of their outer from the crankshaft 15, without being in any way interfering with others, it is possible to perform the maintenance easily. Moreover, by the adjacent arrangement to both the timing transmission 46 _1, 46 ₂ of the generator 30, during operation, since both the timing transmission 46 _1, 46 ₂ oil smear to be scattered from will be applied to the generator 30 ， It can be cooled effectively.

The front and rear timing transmissions 46 ₁ , 46 ₂ and the generator 3 are located on the left side of the crankcase 21.
0, and the starting gear 94 and the primary gear 5 on the other side.
Since the clutch 4 and the clutch 100 are disposed, the weight balance on both sides of the crankcase 21 is good. Therefore, when the motorcycle M is mounted on the vehicle body frame 1, the left and right weight balance of the motorcycle M can be easily achieved. . [Valve system (see FIGS. 2 to 4, 8 and 9)] Each bank 4
_1, 4 ₂ of the cylinder head 23 _1, 23 _2, the intake valve 37 _1, 37 ₂ and exhaust valves 38 _1, 38 _2, intake valve 3
7 _1, provided 37 ₂ Intention to both the banks 4 _1, 4 valley 28 side between the _two. In addition, each cylinder head 23 ₁ , 23 ₂
Have corresponding intake and exhaust valves 37 ₁ , 37 ₂ ; 38 ₁ , 3
The _two ends of cam shafts 41 ₁ , 41 ₂ that open and close drive 82 via rocker arms 39 ₁ , 39 ₂ ; 40 ₁ , 40 ₂ are made parallel to the crankshaft 15, via ball bearings 50, 50 ′, respectively. It is supported. And crankshaft 1
5, a drive timing sprocket 4 fixed to the left end
2 _1, and 42 _2, the cam shaft 41 ₁ of each bank 4 _1, 4 _2,
The driven timing sprockets 43 ₁ , 43 ₂ fixed to the left end of 41 ₂ and the timing chains 44 ₁ , 44 2
₂ is wound. The two drive timing sprockets 42 _1, 42 ₂ has a common boss 45 press-fitted adjacent the outer end of the left journal 17 of the crankshaft 15.

[0025] In Thus, the drive timing sprockets 42 ₁ of the front bank 4 _1, the timing chain 44 ₁ and the driven timing sprocket 43 _1, the cam shaft 41 corresponding to decelerate to a rotation of the crankshaft 15 in 2 minutes ₁ constitutes the front timing transmission 46 ₁ for transmission to the
It the front bank 4 ₁ is disposed on the generator 30 side front timing transmission chamber 47 ₁ formed in the side wall of the. The rear bank 4 ₂ of the drive timing sprockets 42 _2, the timing chain 44 ₂ and the driven timing sprocket 43 _2, a rear timing transmission for transmitting to the cam shaft 41 ₂ corresponding to decelerate to a rotation of the crankshaft 15 in 2 minutes constitute a device 46 _2, it is also the front bank 4
_1, is disposed at the rear timing transmission chamber 47 ₂ formed in the side wall of the generator 30 side.

At this time, the rear timing transmission 46
₂ is axially outside the front timing transmission 46 ₁ ,
That is, it is arranged on the generator 30 side.

The crankshaft 15 is indicated by an arrow R in FIG.
Rotating counterclockwise.
Timing chain 44₁, 44_TwoThe back side is the slack side
Become. In order to give a certain tension to those slack sides,
Imming chain 44₁, 44_TwoOn the loose side of the crank
An arcuate chain ten pivotally supported by the case 21
Shona 48₁, 48_TwoSlidably in contact with each other.
Chain tensioner 48 ₁, 48_TwoThe central part in the longitudinal direction of
The corresponding timing chain 44₁, 44_TwoOne towards
A known tensioner lifter 49 that presses with a constant load
₁, 49_TwoIs each bank 4₁, 4_TwoCylinder block 2
2₁, 22_TwoA bolt 109 is attached to the mounting surface formed on the rear surface.
Mounted on each.

The crankcase 21 is divided into a left case half 21a and a right case half 21b at the left and right central portions, and the outer races of the ball bearings 19 and 20 are mounted on them by light press-fitting in advance. Half 2
1a and 21b, the left and right journals 17 and 18 of the crankshaft 15 are lightly pressed into the inner races of the ball bearings 19 and 20, respectively. crankshaft 15 driven timing sprocket 42 ₁ is press-fitted a common boss 45, 42 ₂ as can pass through the inner race of the left ball bearing 19, the drive timing sprockets 42 _1, 42 outer diameter d ₁ of ₂ above It is set slightly smaller than the inner diameter d ₂ of the inner race of the ball bearing 19. Accordingly, press-fitting of the two drive timing sprockets 42 _1, 42 ₂ of the boss 45 during a single crankshaft 15 becomes possible, it is possible to easily perform press fitting work. The ball bearings 19, 20 are connected to the left and right case halves 21a, 21b and the left and right crank journals 17,
By lightly press-fitting the ball 18, vibration of the ball bearings 19 and 20 during engine operation can be suppressed, and noise can be reduced. [Exhaust system (2, 10 and 11 refer) outlet of the exhaust port 51 ₁ of the front bank 4 ₁ is opened to the front face of the cylinder head 23 _1, to which the front exhaust pipe 13 ₁
Upstream end is connected. The outlet of the exhaust port 52 ₂ of the rear bank 4 _2, the cylinder head 23 ₂ rear,
A rear timing transmission unit 46 ₂ is opened on the right side surface of the opposite side, this upstream end of the rear exhaust pipe 13 ₂ is connected to.

The front exhaust pipe 13 ₁ and the rear exhaust pipe 13
₂ are both front and rear chain transmissions 46 ₁ ,
46 ₂ opposite, with the pipe arranged vertically in the internal combustion engine E the right side, is connected to an exhaust muffler 14 disposed on the right side of the rear wheel 2 to set the downstream end.

[0030] In Thus, the internal combustion engine E as described above, the front bank 4 front and rear timing transmission 46 ₁ on one side of the rear bank 4 ₂ of the offset direction with respect to _1, 4
While disposed concentrate to the 6 _2, since the centralized piping arranged front and rear exhaust pipes 13 _1, 13 ₂ up and down the other side of the internal combustion engine E, and both the timing transmission 46 _1, 46 ₂ both While avoiding interference with the exhaust pipes 13 ₁ and 13 ₂ easily, the entire width of the internal combustion engine E including both the exhaust pipes 13 ₁ and 13 ₂ can be reduced as much as possible.

[0031] The rear bank 4 ₂ of the cylinder head 23
The exhaust port 51 ₂ opened to the rear right side of the _2, so connecting the rear exhaust pipe 13 ₂ is piped to the right side of the motorcycle M, with less bending of the rear exhaust pipe 13 _2, the line It can reduce resistance and contribute to improvement of output performance. [Transmission system (FIGS. 2, 3 and 9 reference) to the crank case 21, transmission case portion 95 projecting in the lower portion of the rear bank 4 ₂ is formed integrally, in this mission case portion 95, An input shaft 96 and an output shaft 97 of the transmission 8 are accommodated immediately after the crankshaft 15 and are arranged in parallel in front and rear thereof, and both ends of the transmission shaft are transmitted through a pair of ball bearings 96, 97; 95 are supported on the left and right side walls. At the right end of the input shaft 96, the inner member 1 of the clutch 100 covered by the right cover 34 joined to the right side of the crankcase 21
A primary driven gear 54b, which meshes with the primary drive gear 54a to form the primary transmission 54, is attached to the inner end of the outer member 102. Also between the input shaft 96 and output shaft 97, transmission gear train G ₁ ~G ₅ a plurality of stages (5 stages in the illustrated embodiment) is arranged to be selected.

[0032] (see FIG. 9) the left side wall 95a of the mission case portion 95 for supporting the left end of the input shaft 96 and output shaft 97, so as to offset to the right of the rear bank 4 ₂ of the timing transmission 46 ₂ It is formed. Therefore, when mounting the tensioner lifter 49 ₂ of the rear bank 4 ₂ of the timing transmission 46 ₂ in the cylinder block 22 ₂ rear surface of the rear bank 4 _2, it is possible to avoid interference with the mission case portion 95.

[0033] In particular, the timing gear 46 ₂ of the rear bank 4 _2, the timing transmission of the front bank 4 ₁ 46
Outward from _1, i.e., it is arranged on the left, to minimize the offset amount to the right of the mission case portion 95 with respect to the crank case 21 can be made compact internal combustion engine E. [Vehicle speed sensor (see FIGS. 2, 9 and 12)] A mounting hole 103 is provided in the rear wall of the transmission case 95, and a vehicle speed sensor 105 for projecting the detection unit 105a into the transmission case 95 through the hole 103 is provided. The transmission case 95 is fixed to the rear wall by bolts 110. The vehicle speed sensor 105, the detection portion 105a of the top driven gear, that is arranged to face the addendum of the driven gear 104 of the top gear train G _5.

The top driven gear 104 is not splined to the output shaft 97, a shift to the left serves as a shift gear for establishing a second speed gear train G _2, also due to the shift, the outer circumference of the gear Does not deviate from the detection area of the vehicle speed sensor 105. Vehicle speed sensor 10
5 is a top driven gear 104 that crosses immediately before the detection unit.
A signal corresponding to the number of teeth is output to a computer (not shown). The computer calculates the vehicle speed from the input signal and displays it on a speedometer (not shown) on an instrument panel (not shown) of the motorcycle M. I do.

As described above, the vehicle speed sensor 105 can be mounted on the rear wall of the transmission case 95 because the vehicle speed sensor 105 that constantly detects the rotation speed of the top driven gear 104 rotating together with the output shaft 97 as the vehicle speed is mounted on the rear wall. ,
Rear bank 4 ₂ is tilted backward to the transmission case portion 95 side, of course, it can be done without being in any way obstructed by the rear exhaust pipe 13 ₂ mounted on its rear.

A rib 106 covering the lower surface of the vehicle speed sensor 105 is integrally formed on the rear surface of the transmission case 95, and a through hole 107 for passing a lead wire 108 of the vehicle speed sensor 105 is formed in the center of the rib 106. Is established.

As shown in FIG. 2, a pair of left and right hangers 1 and a pair of upper and lower hangers 1
12 _1, 112 _2, also on the front of the crankcase 21 is a pair of right and left hangers 112 ₃ are integrally projecting respectively, when mounted on the body frame 1 of the internal combustion engine E, these hangers 112 _1, 112 ₂ , 112 ₃ is coupled to the body frame 1. Rear two sets of hanger part 11
2 _1, 112 surrounded by _2, the vehicle speed sensor 105 by utilizing the transmission case portion 95 rearward of the dead space in which are arranged, thereby increasing the space efficiency.

The rib 106 is provided on the motorcycle M
While traveling, the vehicle speed sensor 105
The through hole 107 through which the lead wire 108 passes also functions as an outlet for rainwater and washing water that has entered the rib 106. [Lubrication and cooling system (see FIGS. 2, 3, 5, and 6)]
As shown in FIGS. 2, 3 and 5, the primary drive gear 54a keyed to the right end of the crankshaft 15 has a pump drive gear 56 and a primary driven gear 54b at two different locations in the circumferential direction. Be engaged.

The pump drive gear 56 is connected to the crankcase 2
The bearing 8 is attached to the right cover 34 joined to the right end face of
6 is keyed to a pump shaft 61 which is supported.
This pump shaft 61 is parallel to the crankshaft 15,
It is arranged so as to be forward and upward.

The inner end of the pump shaft 61 is provided with an inner rotor 59 of a trochoid type oil pump 57 for lubrication, and the outer end thereof is provided with an impeller 60 of a water pump 62 for cooling.
Are respectively fixed. A pump housing 60 that houses the outer rotor 59 of the oil pump 57 is screwed to a partition wall 65 of the crankcase 21 that supports the ball bearing 20. The pump casing 64 that accommodates the impeller 63 is fixed to the outer surface of the right cover with bolts 87. Thus, the oil pump 57 and the water pump 62 are arranged coaxially above and in front of the crankshaft 15, and the oil pump 57 is arranged adjacent to the overrunning clutch 53 radially outward. The case 21 is provided.

The suction port of the oil pump 57 has a
A strike installed in the oil reservoir 66 at the bottom of the link case 21
Connected to sieve 67 (see FIG. 2) via suction pipe 68
The discharge port is connected to the crank through the oil supply passage 69.
Axis 15 and each bank 4₁, 4 _TwoCamshaft 41₁, 41_Two
It is communicated with other lubrication parts.

In the middle of the oil supply passage 69, the crankshaft 15
An oil filter 70 located almost directly above is provided. This
The oil filter 70 is formed on the right cover 34.
A cap attached to the filtration chamber 71 and closing the opening of the chamber 71
The cap 72 is fixed to the right cover 34. In the filtration chamber 71
The inlet chamber 71a on the outer peripheral side of the oil filter 70
Is located upstream of an oil supply passage 69 formed in the crankcase 21.
Communicates with the discharge port of the oil pump 57 via the portion 69a
And an outlet chamber 71b on the inner peripheral side of the oil filter 70.
Are the two branches of the oil supply passage 69 formed in the cap 72.
One of the branch oil passages 6 communicates with the oil passages 69b and 69c.
9b communicates with the lubrication part 73 of the crankshaft 15 system,
The branch oil passage 69c is further connected to the crankcase 21 and the right
The front and rear branch oil passages 69d, 69 at the joint surface of the bar 34
e and branches to the front and rear banks 4 ₁, 4_TwoEach cam
Shaft 41₁, 41_TwoValve system lubrication part 74 including₁, 74_Two
Communicate with

Therefore, the rotation of the crankshaft 15
Through the pump drive gear 56 and the pump shaft 61.
When the oil pump 57 is driven, the oil in the oil sump 66 is
Is sucked up from the strainer 67 and pressurized into the filtration chamber 71.
After being sent and filtered by the oil filter 70, the crank
Lubrication part 73 of shaft 15 system and each bank 4₁, 4_TwoValve train
Lubrication part 74₁, 74_TwoAnd lubricated them
be able to. Moreover, the oil pump 57 and the filtration chamber 7
1, the arrangement and structure of the oil filter 70 and the oil supply passage 69
As a result, the length of the refueling passage 69 is reduced as much as possible,
Part and rear bank 4 ₁, 4_TwoSymmetrical lubrication system
Can be configured in both banks 4₁, 4_TwoThe even lubrication is
It becomes possible.

The oil filter 70 is provided with a relief valve 70b for short-circuiting the inlet chamber 71a and the outlet chamber 71b when the filter element 70a is clogged.

On the other hand, in the water pump 62,
As shown in FIG.₁Through
Radiator 29 (as shown in FIG.
It is arranged in. ), And the discharge pipe 76 is a water pipe
77_TwoThrough front bank 4 ₁Water jacket 2
4₁Connected to the bottom of the

As described above, the front and rear banks 4 ₁ ,
4 _2, each cylinder block 22 _1, 22 ₂ and cylinder heads 23 _1, 23 ₂ series of the water jacket 2
4 _1, 24 provided with a _2, also in the rear bank 4 ₂ of the cylinder head 23 _2, merging chamber open to the front face 80
Is formed, and the water jacket 24 is
The upper part of ₂ is communicated.

Front and rear bank 4₁, 4_TwoOn the opposite side of
Is the corresponding water jacket 24₁, 24_TwoBottom of
Lower joint 78 communicating with₁, 78_TwoProtrude integrally
These joints 78₁, 78_TwoTo valley 28
Lower communicating water pipe 77 to be arranged _ThreeAre connected at both ends.

[0048] In addition to the rear surface of the front bank 4 _1, upper joint 79 ₁ is integrally formed in communication with the top of the jacket 23 _1, and more cylinder head 23 ₂ the lower surface of the rear bank 4 _2, merging chamber 80 upper joint 79 ₂ of the flange communicating is screwed, both ends of these upper joints 79 _1, 79 ₂ in the rear communicating water pipe 77 ₄ disposed in the valley portion 28 are connected to.

The merging chamber with the thermostat 82 is installed in the 80, it holds qualityゝthermostat cover 81 is a cylinder head 23 covering the opening portion of the confluence chamber 80 ₂
Joined to the front of

An outlet joint 83 connected to the outlet of the thermostat 82 is formed integrally with the thermostat cover 81, and the outlet joint 83 is connected to the water pipe 77 _5.
To the inlet of the radiator 29.

[0051] In addition to the upper joint 79 _2, the communication passage 8
Bypass outlet joint 84 communicated with the merging chamber 80 through a 4 'are formed integrally, the bypass outlet joint 84, by a bypass water pipe 85, of the rear bank 4 ₂ carburetor 12 ₂ of the heating chamber, the front It passed sequentially communicated to the bank 4 ₁ of the carburetor 12 ₁ of the heating chamber and the suction tube 75. The bypass outlet joint 84 is formed to have a sufficiently smaller diameter than the outlet joint 83 of the thermostat cover 81.

The thermostat 82 shuts off the space between the merging chamber 80 and the thermostat cover 81 when the water temperature of the merging chamber 80 is equal to or lower than a predetermined temperature, and opens a communication passage 84 ′ between the merging chamber 80 and the bypass outlet joint 84. When the water temperature becomes equal to or higher than a predetermined temperature, communication between the merging chamber 80 and the thermostat cover 81 is established, and
4 'is closed.

Therefore, when the water temperature of the merging chamber 80 is relatively low when the water pump 62 is driven by the rotation of the crankshaft 15 via the pump driving gear 56 and the pump shaft 61, the thermostat 82 is connected to the merging chamber. 8
0 and the thermostat cover 81,
Since the communication passage 84 'is opened, the cooling water is supplied to the water pump 6
The 2, firstly sent from the discharge pipe 76 to the water jacket 24 ₁ of the front bank 4 _1, and then moves to the water jacket of substantially half the second bank immediately through the lower communication water pipe 77 ₃ of the cooling water. The cooling water passing through the water jacket 24 ₁ of the front bank 4 ₁ is moved to the merging chamber 80 of the rear bank 4 ₂ by way of the upper communication water pipe 77 _4,
Joins the cooling water having passed through the rear bank 4 ₂ of the water jacket 24 _2, exits the bypass outlet joint 84 from the merging chamber 80 through the communication passage 84 ', the rear of the carburetor 12 ₂
And heating chamber of the front portion of the vaporizer 12 ₁ via sequentially returned to the suction pipe 75 of the water pump 62, thereafter, repeats the same circulation. By circulating such cooling water without passing through the radiator 29, the warming-up of the internal combustion engine E can be promoted, and the carburetors 12 ₁ and 12 ₂ are heated and icing around the fuel nozzles is performed. Can be prevented.

The warm-up of the internal combustion engine E progresses, and both banks 4 ₁ ,
4 the _second water jacket 24 _1, 24 temperature of cooling water merges ₂ at the joining chamber 80 through the exceeds a predetermined value,
The thermostat 82 communicates between the merging chamber 80 and the thermostat cover 81 and closes the communication passage 84 ′. Therefore, the cooling water flows to the outlet joint 83 side, passes through the radiator 29, and flows through the suction pipe of the water pump 62. Return to 75. Thereafter, the same circulation is repeated, so that both banks 4 ₁ and 4 ₂ can be effectively cooled by the cooling water cooled by the heat radiation action of the radiator 29.

By the way, the lower and upper communicating water pipes 77 ₃ ,
77 ₄ on suffice relatively short, they therefore are arranged in valleys between the two banks, the banks 4 _1, 4 without noticeable hidden between _two, does not impair the appearance of the internal combustion engine E .

The thermostat 82 is provided in the merging chamber 8 in which the cooling water that has cooled the front and rear banks 4 ₁ and 4 ₂ merges.
0, so the thermostat 82 is
By accurately detecting the average water temperature of the _first and _second banks, both banks 4 ₁ ,
4 proper water temperature control of ₂ can be carried out. Moreover, no piping is required for the thermostat 82, and the piping can be simplified.

[0057] further top front of the rear bank 4 _2, the thermostat cover 81 with an outlet joint 83 projecting forwardly is joined, the outlet joint 83
It can be a by reducing the bending of the water pipe 77 ₅ for communicating with the inlet of the radiator 29, the suppress the flow resistance, promote the appearance improvements.

[0058] In the rear bank 4 ₂ of the upper joint 79
The _2, so to form a bypass outlet joint 84 communicated with the merging chamber 80 from a small diameter it together, can make attachment to the rear bank 4 ₂ of the upper joint 79 ₂ and the bypass outlet joint 84 at once, Piping work can be simplified.

The oil pump 57 and the water pump 62 are arranged coaxially, and they are connected to the primary drive gear 54a.
, And the drive system can be simplified.

Further, since the oil pump 57 is arranged radially adjacent to the overrunning clutch 53, an increase in the lateral width of the internal combustion engine E can be suppressed even when the oil pump 57 and the water pump 62 are coaxially arranged.

Further, since the oil pump 57 and the water pump 62 are disposed forward and above the crankshaft 15, the rear part of the crankcase 21 and the transmission case part 95 connected thereto are completely interfered with the oil pump 57 and the water pump 62. Therefore, it is possible to make the engine compact and secure the ground clearance of the internal combustion engine E and to easily reduce the height of the occupant seats 6a and 6b. In this case, due to the above arrangement of the oil pump 57 and the water pump 62, the front part of the crankcase 21 has a slightly swelling shape, but the swelling part is formed by the front bank 4
Since it is absorbed in the dead space below ₁ , it does not hinder downsizing of the internal combustion engine E.

In addition, the drive system of the two pumps 57 and 62 occupying the position above the crankshaft 15 can avoid immersion of the oil in the oil reservoir 66, so that the drive system does not cause oil agitation and reduces power loss. Can contribute.

Further, the input shaft 96 and the output shaft 9 of the transmission 8
7 are arranged horizontally immediately after the crankshaft 15 without any interference by the oil pump 57 and the water pump 62, so that the transmission case 95 is made compact and the upper wall thereof is formed flat. The transmission case 95 and the rear exhaust pipe 1
3 ₂ and a sufficient distance between the rear exhaust pipe 13 ₂
Therefore, it is possible to easily avoid the influence of heat on the transmission case 95 and the transmission 8 accommodated therein. [Starting System (See FIGS. 2 and 7)] A housing recess 88 is formed in the front bottom surface of the crankcase 21, and the starting motor 11 is provided with the axis thereof parallel to the crankshaft 15. You. The casing 89 of the starting motor 11
Fits the cylindrical support portion 89a at one end thereof into a through hole 90 formed in the end wall of the accommodation recess 88 in a liquid-tight manner,
The other end of the mounting arm 89b is fastened to the crankcase 21 with bolts 111, so that it is mounted on the crankcase 21. The tip of a rotor shaft 91 of the starting motor 11 projects into the crankcase 21, and a pinion 92 formed at the tip can drive the starting gear 52 via a reduction gear train 93. . Thus,
The starting gear 52, the overrunning clutch 53, and the reduction gear train 93 constitute a starting transmission 94 that communicates between the starting motor 11 and the crankshaft 15.

As described above, since the starting motor 11 is disposed in front of and below the crankshaft 15, the starting motor 11 does not hinder the rear portion of the crankcase 21 and the transmission case 95 from being made compact. Moreover since will be absorbed in the front bank 4 ₁ below the dead space, not an obstacle to compactness of the internal combustion engine.
Further, the above arrangement of the starting motor 11 allows the reduction gear train 93 to be provided.
Is immersed in the oil in the oil sump 66 at the bottom of the crankcase 21, but this is activated when the engine is started, and is not operated during the operation of the engine to agitate the oil. Therefore, no power loss is caused.

The present invention is not limited to the above embodiments, and various design changes can be made without departing from the scope of the present invention.

[0066]

As described above, according to the first aspect of the present invention, the primary transmission and the rear timing transmission are connected to both ends of the crankshaft, and the transmission case and the rear timing transmission are connected to each other. Since the wall is offset from the rear timing transmission to the primary transmission side, a slight left-right offset between the crankcase body and the transmission case allows the rear bank of the rear bank to be set to a specially small angle. The lifter for the chain tensioner can be mounted on the rear wall of the rear bank without interference with the transmission case, so that the appearance of the V-type internal combustion engine can be improved.

According to a second feature of the present invention, a front timing transmission and a rear timing transmission are connected to one end of a crankshaft adjacent to each other, and the rear timing transmission is connected to the shaft of the front timing transmission. Because it was placed outside the direction,
The amount of offset between the main body of the crankcase and the transmission case can be minimized, and the internal combustion engine E can be made compact. Moreover, due to the concentrated arrangement of the two timing transmissions at one end of the crankshaft, their assemblability and maintainability are improved.

[Brief description of the drawings]

FIG. 1 is a side view of a motorcycle equipped with a V-type internal combustion engine of the present invention.

FIG. 2 is a side view of the internal combustion engine.

FIG. 3 is an enlarged vertical sectional view of a part shown in FIG. 2 in FIG. 3;

FIG. 4 is a sectional view taken along line 4-4 in FIG. 3;

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

FIG. 6 is a cooling water system diagram of the internal combustion engine.

FIG. 7 is a sectional view taken along line 7-7 of FIG. 2;

FIG. 8 is an enlarged view around the front and rear timing transmissions of FIG. 3;

FIG. 9 is an enlarged view around the transmission of FIG. 3;

FIG. 10 is a plan view around the exhaust system of the internal combustion engine.

FIG. 11 is a plan view of a cylinder head of a rear bank of the internal combustion engine.

FIG. 12 is a view taken in the direction of the arrow 12 in FIG. 9;

[Explanation of symbols]

E ... internal combustion engine M ... motorcycle 1 ... body frame 4 ₁ ... front bank 4 ₂ ... rear bank 8 ... transmission 15 ... crankshaft 41 ₁ , 41 ₂ ··· front and rear bank cam shafts 46 ₁ , 46 ₂ ··· front and rear bank timing transmissions 48 ₁ , 48 ₂ ··· front and rear bank chain tensioners 49 ₁ , 49 ₂ ... Front and rear bank lifters 54.

Claims (2)

[Claims] 1. A front and rear bank (4 ₁ , 4 ₂ ) which is opened forward and backward about a crankshaft (15) which is arranged in the left and right direction when mounted on a body frame (1). ,
Crankcase (21) for housing crankshaft (15)
A transmission case (95) accommodating the transmission (8) is integrally connected to the rear of the transmission, and a primary transmission (54) for transmitting power to the transmission (8) is provided on the crankshaft (15). When,
Valve camshafts (4) for the front and rear banks (4 ₁ , 4 ₂ )
The front and rear timing transmissions (46 ₁ , 46 ₂ ) for driving the respective 1 ₁ , 41 ₂ ) are connected to each other, and the corresponding timing transmissions (46, 4) are mounted on the rear wall of each bank (4 ₁ , 4 ₂ ). ₁ , 46 ₂ ) chain tensioner (48 ₁ , 4
8 ₂₎ fitted with lifter (49 _1, 49 ₂₎ for pressing the at V-type internal combustion engine for a motorcycle, the primary transmission (54) and rear timing transmission (46 ₂₎ the crankshaft (15) The rear timing transmission (46 ₂ ) side wall (95a) of the transmission case part (95) is connected to the rear timing transmission (46 ₂ ) by one end.
A V-type internal combustion engine for a motorcycle, wherein the V-type internal combustion engine is offset toward the next transmission (54). 2. A V-type internal combustion engine for a motorcycle according to claim 1, wherein front and rear timing transmissions (46 ₁ , 46 ₂ ) are connected to one end of the crankshaft (15) adjacent to each other. With the rear timing transmission (4
6 ₂₎ that is arranged axially outward of the front timing transmission (46 _1), characterized in, V-type internal combustion engine for a motorcycle.