JP2002047934A - Cooling structure for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provided a cooling structure of an internal combustion engine which can be used for both of water cooling and air cooling without basically changing a main structure. SOLUTION: In a cooling structure for an internal combustion engine, a flow passage 70 around a cylinder bore of a cylinder block 4 is communicated to a flow passage 80 around a combustion chamber of a cylinder head 5 to form a cooling passage, an opening portion to the outside for a flow passage of a cylinder head 5 is water-tightly closed by a cover member 9 to thereby circulate a cooling water in the cooling passage as a water jacket, or to make the air flow in the cooling passage as an air jacket, thereby making an air cooled internal combustion engine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cooling structure for an internal combustion engine, and more particularly to a cooling structure for a cylinder and a cylinder head.

[0002]

2. Description of the Related Art In the case of an ordinary air-cooled internal combustion engine, cooling air introduced into a cover for covering a cylinder or the like is guided by the rotation of a blower fan supported at one end of a crankshaft to guide the cylinder and cylinder head. By flowing between a number of fins on the outer surface, heat can be taken away and the internal combustion engine can be cooled.

In the internal combustion engine having the above-described air-cooled structure, it is impossible to use the flow of the cooling air for the flow of the cooling water and divert it to the water-cooled internal combustion engine. That is, since a large number of fins exposed to the cooling air are open to the outside, cooling water cannot be held and flown between the fins.

Accordingly, an example in which a cooling air passage is formed by partially covering the space between the fins through which the cooling air flows with a partition wall (Japanese Utility Model Application Laid-Open No. 56-103).
No. 642), and it is possible to use this cooling air passage as a cooling water passage.

[0005]

However, the cooling operation as air cooling is based on the fact that cooling air flows between a number of fins that open outward between the fins, so that partition walls are provided between all the fins. Therefore, when water cooling is used, the cooling water passage is insufficient, and the cooling effect cannot be expected.

The present invention has been made in view of the above points, and its object is to use an internal combustion engine which can be used for both water cooling and air cooling without basically changing the main structure, and which can expect both cooling effects. The point is to provide a cooling structure for the engine.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, a flow path around a cylinder bore of a cylinder block communicates with a flow path around a combustion chamber of a cylinder head. A cooling channel is formed, and an opening to the outside of the channel of the cylinder head is closed in a water-tight manner with a cover member to circulate cooling water as a water jacket to form a water-cooled internal combustion engine. And an air-cooled internal combustion engine that allows air to flow through the cooling passage as an air jacket.

[0008] Since the flow paths around the cylinder bore and the combustion chamber are formed as cooling flow paths through which either cooling water or air can flow, it is basically easy to switch between water cooling and air cooling without changing the main structure of the internal combustion engine. Can be used, and a cooling effect can be expected in both cases of water cooling and air cooling.

According to a second aspect of the present invention, in the cooling structure for an internal combustion engine according to the first aspect, when the water-cooled internal combustion engine is used, the cover member is formed integrally with a thermostat case.

Since the thermostat holding case, which is not required for air cooling and used only for water cooling, is formed integrally with the cover, the thermostat can be mounted without changing the main structure of the cylinder block or cylinder head for mounting the thermostat. It is easy to attach and detach, and can be easily applied to both water cooling and air cooling.

According to a third aspect of the present invention, in the cooling structure for an internal combustion engine according to the first or second aspect, when the water-cooled internal combustion engine is used, the cover member is formed integrally with the spark plug holder. Features.

Since the spark plug holder is formed integrally with the cover member, in order to set the spark plug to an appropriate heat value in any of the water-cooled and air-cooled cooling systems, it is appropriately designed for each cooling system. By changing to the cover member, it is possible to easily cope without changing the main structure of the cylinder head.

According to a fourth aspect of the present invention, in the cooling structure for an internal combustion engine according to the first aspect, air is introduced into one surface of the cylinder block so as to communicate with an air jacket around the cylinder bore and is opposed to the upstream side of the blower. Port, an air outlet port opened to communicate with the outside from the air jacket on the other surface of the cylinder block, and cooling air flowing into the air inlet port flows through the air jacket to cool around the cylinder bore. An air-cooled internal combustion engine flowing out of the air outlet or the like is provided.

[0014] The water-cooled internal combustion engine can be used as an air-cooled internal combustion engine by a simple process of providing an air inlet and an air outlet at required portions of a cylinder block without changing the main cooling structure.

According to a fifth aspect of the present invention, in the cooling structure for an internal combustion engine according to the fourth aspect, a fan cover for supporting a blower fan is covered on at least one surface of the cylinder block, and the blower is provided so as to face the air inlet. It is characterized by disposing a fan.

Since the fan cover that covers at least one surface of the cylinder block supports the blower fan so as to face the air inlet of the cylinder block, the air blown by the blower fan efficiently flows into the air inlet and the cylinder block and the cylinder. The cylinder block and the cylinder head can efficiently be cooled by flowing through the air jacket of the head and flowing out of the air outlet or the like.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described below with reference to FIGS. First, a water-cooled internal combustion engine 1 that circulates and cools cooling water will be described with reference to FIGS. 1 to 16.

The water-cooled internal combustion engine 1 is a single-cylinder four-cycle internal combustion engine, and is mounted vertically with the crankshaft 2 directed in the front-rear direction of the vehicle body. 1 is a front view of the entire internal combustion engine 1, FIG. 2 is a rear view of the same, FIG. 3 is a cross-sectional view taken at right angles to the crankshaft 2, and FIG. 3 shows a cross section of the member.

The water-cooled internal combustion engine 1 comprises a lower crankcase 3 with a crankshaft 2 interposed therebetween, a cylinder block 4 integral with the upper crankcase, a cylinder head 5 sequentially stacked on the cylinder block 4, and a cylinder head cover 6. The cylinder of the cylinder block 4 projects slightly upward in the right direction, and has a split surface of the lower crankcase 3, the cylinder block 4, and the cylinder head 5 perpendicular to the cylinder center axis.

As shown in FIG. 1, on the front of the internal combustion engine 1,
A rectangular radiator 7 is provided so as to cover the central portion of the lower crankcase 3 and the cylinder block 4. A charging device 8 is attached to an upper side wall of the cylinder block 4 in FIG. A first cover member 9 for closing a water jacket 80, which is a cooling channel of the cylinder head 5, is attached to a side surface.

A water pump 10 is mounted on the front of the feeding device 8, and a cooling water hose 11 extending from an outlet tank 7a (left side in FIG. 1) of the radiator 7 is connected to the water pump 10.
And a cooling water hose 12 extending from the first cover member 9 is connected to an inflow-side tank 7b (right side in FIG. 1) of the radiator 7.

Referring to FIG. 1, an exhaust pipe 13 extends from the front side wall of the cylinder head 5, and a breather pipe 14 projects upward from the upper side wall of the cylinder head 5 near the cylinder head cover 6. A rubber cap 23 of the ignition plug 22 protrudes from the cover member 9.

As shown in FIG. 2, on the rear surface of the water-cooled internal combustion engine 1, an oil pump driven by being connected to the crankshaft 2 at the mating surface of the lower crankcase 3 and the cylinder block 4 is provided.
A circular hole 15 into which the output shaft 25 protrudes is opened in the lower crankcase 3.

A supply suction pipe 17 and a supply discharge pipe 18 extend from a left bulging portion of the supply device 8, and the supply discharge pipe 17 is connected to a supply port from a rear side wall of the cylinder head 5. . An electromagnetic solenoid 19 for oil supply is attached to the rear surface of the feeding device 8, and an intake pipe 20 further extends from a rear side wall of the cylinder head 5. A reserve pipe 21 extends from the rear surface of the first cover member 9.

Referring to FIGS. 3 and 4, a reciprocating piston 31 is slidably fitted to the cylinder liner 30 of the cylinder portion of the cylinder block 4, and the piston 31 and the crank pin 2a of the crankshaft 2 are slidably fitted. And a connecting rod 32.

As shown in FIG. 4, the crankshaft 2 is rotatably supported by a pair of bearing holders 33 and 34 via main bearings 35 and 36, and the front side walls of the lower crankcase 3 and the cylinder block 4 are formed. An AC generator 37 is provided at a front portion of the crankshaft 2 that penetrates and protrudes. An outer rotor 37b that rotates around an inner stator 37a is fixed to a front end of the crankshaft 2, and a cooling surface is provided at a front surface of the outer rotor 37b. Fan 38
Is attached. The radiator 7 is arranged in front of the cooling fan 38.

On the other hand, a pump drive shaft 24a of a trochoidal oil pump 24 fitted in the circular hole 15 is coaxially connected to a rear end of the crankshaft 2 which is supported by a main bearing 36 and protrudes. The oil sucked from the oil reservoir at the bottom of the lower crankcase 3 and the cylinder block 4 and discharged from the oil pump 24 is supplied to the oil passage 24b in the pump drive shaft 24a, the lower crankcase 3, the cylinder block 4 and the cylinder head. The oil is supplied to the lubrication points of the internal combustion engine 1 and the transmission through oil passages 24c and 24d provided in the transmission 5.

The timing gear 40 fitted to the rear end of the crankshaft 2 meshes with the cam gear fitted to the camshaft 41 so that the camshaft 41 rotates once every two rotations of the crankshaft 2. Have been. Referring to FIG. 3, three cams are formed integrally with the cam shaft 41, and the first rocker arm shaft 42
A first intake rocker arm (not shown), a first supply rocker arm 43, and a first exhaust rocker arm that are coaxially supported on
It is in contact with 44.

On the other hand, a second intake rocker arm (not shown) for driving the intake valve 51 to open coaxially with the second rocker arm shaft 45 in the cylinder head 5, a second supply rocker arm 46 for driving the supply valve 52 to open, The second for opening and driving the exhaust valve 53
An exhaust rocker arm 47 is pivotally supported, an intake pull rod (not shown) is connected between the first and second intake rocker arms, and a supplied pull rod 48 is provided between the first and second supplied rocker arms 43 and 46.
And an exhaust pull rod 49 connects between the first and second exhaust rocker arms 44 and 47.

The rotation of the camshaft 41 which makes one rotation every two rotations of the crankshaft 2 by the above-described valve driving mechanism causes the intake valve to rotate via the first rocker arm, the pull rod and the second rocker arm.
The opening of the intake pipe 20, the supply pipe 55, and the exhaust pipe 13 on the combustion chamber 5a side is opened and closed at a predetermined timing by driving the supply pipe 51, the supply valve 52, and the exhaust valve 53.

As shown in FIG. 4, the cylinder head 5 has
An intake pipe 20, a supply pipe 55, and an exhaust pipe 13 made of a pipe material opened to a combustion chamber 5a formed in the cylinder head 5 are cast.
The fuel injected from the fuel injection valve 56 mounted on the mounting portion 20a protruding from the intake pipe 20 and the intake air are mixed and supplied to the combustion chamber 5a, and the supply air is added.

A primary drive gear 57 provided on the outer periphery of the second crank web 2b of the crankshaft 2 meshes with a primary driven gear 58 of a starting clutch 59 rotatably mounted on the output shaft 25, and Power is transmitted to the output shaft 25, which is the main shaft of the transmission, via the starting clutch 60.

Next, the cooling structure of the cylinder block 4 and the cylinder head 5 will be described. Cylinder block 4
FIGS. 5 to 8 show single-part drawings. FIG. 5 is a top view of the cylinder block 4 as viewed from above the cylinder center axis direction.
FIG. 6 is a front view (viewed along the arrow VI in FIG. 5), and FIG. 7 is a rear view (viewed along the arrow VII in FIG. 5).

A water jacket 70 is provided around the cylinder liner 30 in the center cylinder portion of the cylinder block 4.
(See FIGS. 3, 4, 5, and 8), and a cooling water introduction passage 71 penetrates from the front surface toward the water jacket 70 as shown in FIGS.

One circular recess 72 is formed from the front surface of the cylinder toward the water jacket 70 (see FIGS. 6 and 8), and a circular recess 72 is formed from the rear surface of the cylinder toward the water jacket 70. Two recesses 73 and 74 are formed (see FIGS. 7 and 8). The recesses 72, 73, 74
When used as an air-cooled internal combustion engine, this is a portion that is used as an air inlet / outlet by replacing a casting pin and penetrating a mold for casting a cylinder block.

The cylinder block 4 is provided with a mounting bracket 75 having a large circular hole protruding from a portion extending to one side of the mating surface with the lower crankcase 3 and a side wall of the cylinder portion. The feeding device 8 is attached.

Next, the cylinder head 5 will be described with reference to FIGS. A water jacket 80 is formed around the combustion chamber 5a, which is defined by an intake pipe 13, an exhaust pipe 20, a supply pipe 55, and a mounting hole 82 in which the ignition plug 22 is mounted, which communicates with the combustion chamber 5a of the cylinder head 5. ing. The water jacket 80 of the cylinder head 5 communicates with the water jacket 70 of the cylinder block 4 at a mating surface.

The space forming the water jacket 80 has a rectangular opening 81 on one side surface of the cylinder head 5 as shown in FIG.
Is fitted and watertightly attached to the water jacket
80 is closed.

A valve operating system such as a second rocker arm shaft 45 and a second rocker arm is disposed in a valve operating system space 84 (see FIG. 10) above the partition wall that partitions the upper part of the water jacket 80. A breather chamber 85 is formed in a part of the valve system space 84, and the breather pipe 14 extends from the breather chamber 85. The cylinder head cover 6 is covered so as to cover the rectangular opening of the valve operating space 84.

A feed pipe cast into the cylinder head 5
55 is formed to be curved from the opening of the combustion chamber 5a to the connection opening 5b provided on the same split surface as shown in FIG.
The supply / discharge pipe 18 extending from the supply device 8 is connected to the connection opening 5b, and supply air is supplied to the combustion chamber 5a.

The first cover member 9 for closing the rectangular opening of the water jacket 80 opened on the side wall of the cylinder head 5
Will be described with reference to FIGS. As shown in FIG. 13, the first cover member 9 is provided with a groove 91 a for fitting a sealing material into a mating surface 91 mated with the mating surface 83 of the cylinder head 5, and bulges outward from the mating surface 91. An inner space 90 is formed inside by the outer wall 92 thus formed.

12 and 13, a cylindrical spark plug holder 93, which protrudes from the center of the outer wall 92 in the left-right direction into the inner space 90 and in which the spark plug 22 is mounted, is formed so as to further protrude from the mating surface 91. . A holding case 94 to which a thermostat 97 is attached to one of the left and right side surfaces of the outer wall 92 and to which the cooling water hose 12 is connected, and a connecting case 95 to which the reserve pipe 21 is connected to the other are integrally formed. A mounting cylinder 96 of a water temperature sensor 98 is formed adjacent to 93.

A thermostat 97, a water temperature sensor 98, and a reserve pipe 21 are mounted on the first cover member 9, and the first cover member 9 is inserted into an opening of the water jacket 80 of the cylinder head 5.
FIG. 16 shows a state where the mating surfaces 83 and 91 are joined together with a sealing material interposed therebetween, and the four corners are fastened and fixed with bolts 99.

The first cover member 9 tightly contacts the peripheral mating surface 91 with the mating surface 83 of the cylinder head 5 via a sealing material, and at the same time, attaches the tip of the ignition plug holder 93 projecting inside to the cylinder head 5. It fits into the mounting hole 82.
Then, the water jacket 80 of the cylinder head 5 and the first
The inner space 90 of the cover member 9 is in communication with the inner space 90, and the cooling water circulates.

Cylinder block 4 and cylinder head 5
Is configured as described above. The water pump 10 for circulating the cooling water is attached to the front of the feeding device 8 as described above, and as shown in FIGS. 1 and 4, a pump cover 10b for covering the pump case 10a of the water pump 10 from the front. Is connected to a cooling water hose 11.

Pump case 10a and pump cover 10b
Extends to a part of the cylinder block 4 to cover the cooling water introduction passage 71 on the front surface of the cylinder block 4 (see FIG. 1), and a cooling water passage 10c is formed toward the cooling water introduction passage 71. (See FIG. 4).

The cooling water circulation path by the water pump 10 will be described below. When the water pump 10 is driven, cooling water is sucked from the radiator 7 into the pump case 10a through the cooling water hose 11 and supplied to the water jacket 70 of the cylinder block 4 from the cooling water introduction path 71 through the cooling water passage 10c. ,
Cooling around the cylinder bore is performed.

Water jacket of cylinder block 4
Since 70 communicates with the water jacket 80 of the cylinder head 5, the cooling water moves from the cylinder block 4 to the water jacket 80 of the cylinder head 5 and cools around the combustion chamber 5 a of the cylinder head 5.

The water jacket 80 of the cylinder head 5
The cooling water flowing into the inner space 90 of the first cover member 9 is adjusted in flow by the thermostat 97, discharged to the cooling water hose 12, and returned to the radiator 7. The internal space 90 of the first cover member 9 is supplied with cooling water from the reserve pipe 21.

The cylinder block 4 and the cylinder head 5 are cooled by circulating the cooling water through the cooling water circulation path as described above. The thermostat 97 and the holding case 94 of the water temperature sensor 98 and the mounting cylinder 96 which are not necessary for air cooling and are used only for water cooling are formed integrally with the first cover member 9. The thermostat 97 and the water temperature sensor 98 can be easily attached and detached by changing the cover member without changing the main body of the cylinder block 4 or the cylinder head 5 for mounting, and both water cooling and air cooling can be easily applied.

Further, since the spark plug holder is formed integrally with the cover member, in order to set the spark plug to an appropriate heat value in any of the water-cooled and air-cooled cooling systems, it is appropriately designed for each cooling system. By replacing the cover member with the one described above, it is possible to easily cope without changing the main structure of the cylinder head.

As described above, components unnecessary and need to be changed at the time of air cooling are collectively attached to the first cover member 9, so that the main structures of the cylinder block 4 and the cylinder head 5 themselves are not changed. It is easy to apply to air cooling.

Next, the internal combustion engine 101 applied to the air cooling system will be described with reference to FIGS. The air-cooled internal combustion engine 101 generally has a lower crankcase 103, a cylinder block
104, a cylinder head 105, and a cylinder head cover 106. The lower crankcase 103 and the cylinder head cover 106 are exactly the same as the lower crankcase 3 and the cylinder head cover 6 in a water-cooled system. The basic structure of the cylinder block 4 and cylinder head 5 remains the same,
The only difference is the cooling structure.

That is, the air-cooled cylinder block 104
Can be manufactured using the same mold as the water-cooled cylinder block 4, using a partially cast pin, and performing simple boring. In addition, the air-cooled cylinder head 105 can be manufactured by casting a part of the same mold as the water-cooled cylinder head 5 without using a molding pin and performing a slight drilling process.

With respect to the cylinder block 104, the recesses 72, 73, and 73 provided from the outside toward the water jacket 70 of the cylinder portion of the cylinder block 4 are provided.
Reference numeral 74 (refer to FIG. 8) denotes a recess which can be inserted into a mold for casting the cylinder block by replacing the casting pin with a casting pin. An air inlet 112 and air outlets 113 and 114 on the rear surface are formed to communicate with the air jacket 110 corresponding to the water jacket. That is, the water jacket 70 in the water cooling system is used as the air jacket 110 as it is.

In the case of the cylinder block 104, an air outlet 115, which is a circular hole penetrating one side wall of the cylinder portion toward the air jacket 110, is additionally formed. In the water-cooled cylinder head 5, a cooling water introduction passage 71 is drilled from the front surface toward the water jacket 70, but this process is not required in the air-cooled cylinder head.

Accordingly, the air introduced into the air jacket 110 around the cylinder bore from the air introduction port 112 vacated on the front surface is derived from the air outlet ports 113 and 114 on the rear face and the air outlet port 115 on the side face, and part of the cylinder block. 104 air jacket 110 to cylinder head 105 air jacket
Flows to 120.

Members that can be used in common with the water-cooled internal combustion engine 1 are denoted by the same reference numerals. In the air-cooled internal combustion engine 101, there is no charging device, and therefore, there is no member related to charging in the valve train. Referring to FIG. 18, cooling fan 130 having large blades is attached to the front wall of outer rotor 37b of AC generator 37 provided on crankshaft 2 protruding forward from cylinder block 104. Is covered by the fan cover 131 from the front.

As shown in FIG. 17, the fan cover 131
A circular portion 131a covering the front of the lower crankcase 103 and the cylinder block 104 in a substantially circular shape at the center of the crankshaft 2 and extending from a part of the circular portion 131a to a second cover member 109 covering a part of the cylinder head 105. Consisting of an extension 131b,
A large circular air inlet 131c is formed at the center of the circular portion 131a.

The extension 131b of the fan cover 131 covers the air inlet 112 on the front surface of the cylinder block 104. Therefore, the air inlet 112 of the cylinder block 104
Is directed toward the cooling fan 130 in the fan cover 131, so that the air sucked and blown by the cooling fan 130 can be efficiently introduced into the air jacket 110 in the cylinder block 4.

On the other hand, the extension 131b of the fan cover 131 is a second cover for covering the opening of the air jacket 120 of the cylinder head 105.
A part of the air that is connected to the cover member 109 and is sucked by the cooling fan 130 is guided by the extending portion 131b and is introduced from the second cover member 109 to the air jacket 120 of the cylinder head 105.

The structure of the cylinder head 105 is basically the same as that of the cylinder head 5 except for the structure shown in FIGS.
As shown in FIG. 1, there is no charging pipe, and the charging pipe 55 is provided in the combustion chamber 5a.
The port through which the feed valve 52 penetrated by casting was closed, and instead of the feed pipe 55, the air outlet pipe 12 was opened.
1 is cast into the cylinder head 105 so that the air jacket 120 of the cylinder head 105 communicates with the outside.

That is, the air outlet pipe 121 communicates from the air jacket 120 of the cylinder head 105 to the air outlet 105b provided on the split surface as shown in FIG. The second cover member 109 for closing the opening of the air jacket 120 of the cylinder head 105 has no mounting or connection of a thermostat, a water temperature sensor, a reserve pipe, etc. other than having a spark plug holder for mounting a spark plug.

The internal cooling structure as described above is
1, the air sucked by the cooling fan 130 into the fan cover 131 covering the front surface
04 is introduced into the air jacket 110 from the air inlet 112 and cools around the cylinder bore.
4 and 115, the remainder enters the air jacket 120 on the cylinder head 105 side, cools around the combustion chamber 105a, passes through the air outlet pipe 121 from the air jacket 120, and connects with the cylinder block 104 from the air outlet 105b. Is discharged to the outside through the gap of the split surface.

On the other hand, the cooling fan 130 causes the fan cover 131
The air sucked into the air and guided to the extension portion 131 b is supplied from the second cover member 109 to the air jacket 12 of the cylinder head 105.
The air is introduced into the combustion chamber 105a and is cooled around the combustion chamber 105a.

The internal combustion engine 101 has the above-described internal air cooling structure, and has a large number of cooling fins protruding from the outer surfaces of the cylinder block 104 and the cylinder head 105.

As described above, the air inlet 112 and the air outlets 113, 11 are provided at required portions of the cylinder block of the water-cooled internal combustion engine.
4, 115 are provided, and the opening position of the supply pipe of the cylinder head is changed to form the air outlet pipe 121, so that the air-cooled internal combustion engine can be used without changing the main cooling structure.

In the case of a motorcycle, an air-cooled internal combustion engine whose body is relatively light is preferable, and an example in which the air-cooled internal combustion engine 101 is mounted on a motorcycle 200 is shown in FIGS. 22 and 23. The motorcycle 200 is a scooter-type motorcycle, and a body frame is formed by a pair of left and right main frames 202 extending right and left from a head pipe 201 and extending downward, bending backward at a lower end to form a horizontal portion, and forming a horizontal portion at a rear portion. Bends diagonally upward to form rear end portions 202a, 202a.
a, a cross member 202b is erected between 202a,
The rear frame 203 is connected to the left and right rear ends 202a, 202a and extends obliquely rearward and upward.

The head pipe 201 pivotally supports a handle 205 via a steering shaft 204, extends obliquely downward from a lower portion of the steering shaft 204 so that a front arm 206 turns rightward, and extends through a link 207 to a front wheel 208. Is supported from one side.

This air-cooled internal combustion engine 101 is arranged behind a rear end 202a of the main frame 202 which is inclined obliquely upward.
Is a swing unit type internal combustion engine in which a transmission case 210 extends rearward from a rear mating surface of the lower crankcase 3 and a rear wheel 211 is pivotally supported by a rear end gear case 210a.

In the air-cooled internal combustion engine 101, the front face covered with the fan cover 131 faces between the left and right rear ends 202a, 202a of the main frame 202, the transmission case 210 faces rearward, and the cylinder head 105 moves to the right. The vehicle is connected to and supported by the vehicle body frame in a posture that is tilted to near the horizontal.

The left and right rear end portions 202a, 20 of the main frame 202
Brackets 212, 212 project along the rear surface of the bracket 2a, and the air-cooled internal combustion engine 101 has a transmission case 210, a rear part pivotally supported by engine pivots 213, 213 of the brackets 212, 212. It is pivotally supported so as to be able to swing up and down together with the wheel 211. A rear cushion 214 is interposed between a gear case 210a that supports the rear wheel 211 and the rear frame 203.

Above the air-cooled internal combustion engine 101, a storage box 220 such as a helmet is provided so as to be supported by the rear frame 203, and a seat 221 is provided to open and close the upper opening of the storage box 220. A fuel tank 215 is installed and supported between the left and right horizontal portions of the main frame 202, and a step floor 222 covers the fuel tank 215.

The front portion of the main frame 202 from the steering shaft 204 is connected to the front cover 223 and the leg shield.
The front fender 225 covers an area above the front wheel 208.

In the air-cooled internal combustion engine 101, the front fan cover 131 is directed between the left and right rear ends 202a, 202a of the main frame 202. Therefore, the air intake 131c opened in front of the fan cover 131 is provided in the storage box 220. An opening is provided in a space between the fuel tank 215 and the fuel tank 215 (see FIG. 22) so that air can be easily taken in.

As described above, the motorcycle having a relatively light vehicle body
The air-cooled internal combustion engine 101 is mounted on the 200, and the water-cooled internal combustion engine 1 is mounted on a three-wheeled motor vehicle and a four-wheeled motor vehicle having a heavier body.

FIG. 24 shows an example in which the water-cooled internal combustion engine 1 is mounted on a three-wheeled motor vehicle 300. This tricycle 300 is
The main frame 202 used for the motorcycle 200 is shared with the main frame 302, and the support structure of the front wheel 308 is the same as that of the motorcycle 200.

A rear frame 303 extends from the rear end of the main frame 302, and the water-cooled internal combustion engine 1 is mounted on a bracket attached to the rear frame 303 via an engine pivot 304 with its front portion pivotally supported. Can be

The present water-cooled internal combustion engine 1 is also of a swing unit type. The transmission case 310 is combined with the lower crankcase 3 and a differential case 311 is integrally provided at the rear end of the transmission case 310. Rear wheels 312, 312 are fitted to an axle projecting left and right from the rear.

A pair of left and right subframes 307 extending obliquely upward and rearward from a Neidhart plate 306 installed between the rear portions of the main frame 302 pass over the water-cooled internal combustion engine 1, and the left and right subframes 307 are connected. A rear cushion 308 is interposed between the rear end and the differential case 311.

In the water-cooled internal combustion engine 1 mounted on the three-wheeled motor vehicle 300, the radiator 7 on the front
It is attached to the space between 7 and 307 so as to be able to swing up and down together with the rear wheels 312 and 312 at the rear.

Next, the water-cooled internal combustion engine 1
25 is shown in FIG. Automobile 400
The main frame 402 can share the same frame as the main frames 202 and 203 used for the motorcycle 200 and the motorcycle 300.

The left and right horizontal portions of the main frame 402 are reinforced by side pipes 403, 403 oriented in the front-rear direction. A dash frame is provided at the front end of the side pipes 403, 403.
Front frames 405, 405 are extended forward through 404, and a front bumper 406 is provided between the front ends.

The front wheels 408, 408, which extend to the left and right from the vicinity of the lower end of the steering shaft 407, have front wheels.
409, 409 are pivotally supported, and front cushions 410, 410 are interposed between the respective front arms 408, 408 and the dash frame 404. A pillar pipe 411 having a front end connected to the rear end of the side pipes 403 is bent obliquely upward and stands upright.

A pair of left and right rear arms 413, 413 extending rearward from a Neidhart plate 412 erected between the rear portions of the main frame 402 have engine pivots 414, 4.
The water-cooled internal combustion engine 1 is mounted with its front part pivotally supported via.

This water-cooled internal combustion engine 1 is
The transmission case 420 is united with the lower crankcase 3 and a differential case 421 is integrally provided at the rear end of the transmission case 420 in the same manner as that mounted on the axle which is protruded left and right from the differential case 421. Rear wheels 422, 422 are fitted.

On the other hand, a pair of left and right rear frames 415, 415 extend obliquely upward from the rear end of the main frame 402. The rear frames 415, 415 and the differential case
Rear cushions 416, 41 between the left and right axle sleeves of 421
6 are interposed.

In the water-cooled internal combustion engine 1 mounted on the automobile 400 in this manner, the radiator 7 on the front
Located between 3,413 and facing the front space, rear wheels 422,422
It is mounted so that it can swing freely.

As described above, the present internal combustion engine can be easily used for both water cooling and air cooling without changing the main structure. On the other hand, it can be easily mounted on a three-wheeled motor vehicle 300 and a four-wheeled motor vehicle 400 as a water-cooled type.

[Brief description of the drawings]

FIG. 1 is a front view of an internal combustion engine applied to a water cooling system.

FIG. 2 is a rear view of the same.

FIG. 3 is a cross-sectional view taken at right angles to a crankshaft;

FIG. 4 is a sectional view of the same section and other members taken along a plane including a crankshaft, showing a cooling water path.

FIG. 5 is a top view of a cylinder block in the water-cooled internal combustion engine.

FIG. 6 is a front view of the same.

FIG. 7 is a rear view of the same.

FIG. 8 is a sectional view taken along the line VIII-VIII in FIG.

FIG. 9 is a side view of a cylinder head in the water-cooled internal combustion engine.

FIG. 10 is a top view of the same.

11 is a cross-sectional view taken along line XI-XI in FIG.

FIG. 12 is a front view of the first cover member.

FIG. 13 is a rear view of the same.

FIG. 14 is a sectional view taken along line XIV-XIV in FIG.

FIG. 15 is a sectional view taken along line XV-XV in FIG.

FIG. 16 is a side view showing a state where a first cover member and the like are attached to a cylinder head.

FIG. 17 is a front view of an internal combustion engine applied to an air cooling system.

FIG. 18 is a top view of a cylinder block in the air-cooled internal combustion engine and a partial cross-sectional view taken along a crankshaft.

FIG. 19 is a sectional view of the cylinder block corresponding to FIG. 8;

FIG. 20 is a top view of a cylinder head in the air-cooled internal combustion engine.

FIG. 21 is a sectional view taken along line XXI-XXI in FIG.

FIG. 22 is a side view of a motorcycle equipped with an air-cooled internal combustion engine.

FIG. 23 is a perspective view of the motorcycle with a cover and the like omitted.

FIG. 24 is a perspective view of a motorcycle equipped with a water-cooled internal combustion engine, with a cover and the like omitted.

FIG. 25 is a perspective view of a four-wheeled motor vehicle equipped with a water-cooled internal combustion engine with a cover and the like omitted.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Water-cooled internal combustion engine, 2 ... Crankshaft, 3 ... Lower crankcase, 4 ... Cylinder block, 5 ... Cylinder head,
6 ... Cylinder head cover, 7 ... Radiator, 8 ... Charging device, 9 ... First cover member, 10 ... Water pump, 11 ... Cooling water hose, 12 ... Cooling water hose, 13 ... Exhaust pipe, 14 ... Breezer pipe, 15, 16… Circular hole, 17… Feeding supply pipe, 18… Feeding discharge pipe, 19… Electromagnetic solenoid, 20… Intake pipe, 21… Reserve pipe, 22… Spark plug, 23… Rubber cap, 24…
Oil pump, 25 ... output shaft, 30 ... cylinder liner, 31
... piston, 32 ... connecting rod, 33, 34 ... bearing holder,
35, 36: Main bearing, 38: Cooling fan, 40: Timing gear, 41: Cam shaft, 42: First rocker arm shaft, 43: First feeding rocker arm, 44: First exhaust rocker arm, 45: Second
Rocker arm shaft, 46 ... second feeding rocker arm, 47 ... second
Exhaust rocker arm, 48… Pull pull rod, 49… Pull pull rod, 51… Intake valve, 52… Pull valve, 53… Exhaust valve, 55… Pull pipe, 56… Fuel injection valve, 57… Primary drive gear, 58… Primary driven gear , 60 ... launch clutch, 70 ... water jacket,
71 ... cooling water introduction path, 72, 73, 74 ... recess, 75 ... mounting bracket, 80 ... water jacket, 81 ... rectangular opening, 82 ... mounting hole, 83 ... mating surface, 84 ... valve system space, 85 ... breather Chamber, 90… Inner space, 91… Matching surface, 92… Outer wall, 93… Spark plug holder, 94… Retention case, 95… Connection case, 96…
Mounting tube part, 97 ... thermostat, 98 ... water temperature sensor, 99 ...
Bolt, 101: air-cooled internal combustion engine, 103: lower crankcase, 104: cylinder block, 105: cylinder head, 10
6… Cylinder head cover, 110… Air jacket, 112
... air inlet, 113, 114, 115 ... air outlet, 120 ... air jacket, 121 ... air outlet, 130 ... cooling fan, 131
... Fan cover, 200 ... Motorcycle, 201 ... Head pipe, 202 ... Main frame, 203 ... Rear frame, 204 ...
Steering shaft, 205 ... steering wheel, 206 ... front arm, 207 ... link, 208 ... front wheel, 210 ... transmission case, 211 ... rear wheel, 212 ... bracket, 213 ... engine pivot, 214 ... rear cushion, 220 ... storage box, 221
… Seat, 222… step floor, 223… front cover, 224… leg shield, 225… front fender,
300: Motorcycle, 302: Main frame, 303: Rear frame, 304: Engine pivot, 306: Neidhart plate, 307: Sub frame, 308: Rear cushion, 31
0 ... transmission case, 311 ... differential case, 312
... Rear wheel, 400 ... Tricycle, 402 ... Main frame, 403
… Side pipe, 404… dash frame, 405… front frame, 407… steering shaft, 408… front arm, 409… front wheel, 410… front cushion, 411
… Pillar pipe, 412… Neidhart plate, 413… rear arm, 414… engine pivot, 415… rear frame, 416… rear cushion, 420… transmission case, 421…
Differential case, 422 ... rear wheel.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) F01P 5/06 502 F01P 5/06 502D 7/16 502 7/16 502B F02F 1/04 F02F 1/04 1 / 08 1/08 Z 1/10 1/10 BD (72) Inventor Noriaki Okano 1-4-1, Chuo, Wako, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Takashi Tsutsumizaki Wako, Saitama Prefecture 1-4-1 Chuo F-term in Honda R & D Co., Ltd. (Reference) 3G024 AA02 AA04 AA21 AA26 AA36 AA71 CA05 CA19 CA23 CA24 CA30 DA01 DA03 DA08 DA16 EA01 EA04

Claims (5)

[Claims] 1. A cooling passage is formed by communicating a flow passage around a cylinder bore of a cylinder block with a flow passage around a combustion chamber of a cylinder head, and a cover member for opening a part of the passage of the cylinder head to the outside. By closing the cooling passages in a water-tight manner with a water jacket, the cooling water can be circulated to form a water-cooled internal combustion engine by circulating cooling water, and the cooling passages can be made into an air-cooled internal combustion engine by flowing air as an air jacket. A cooling structure for an internal combustion engine, comprising: 2. The cooling structure for an internal combustion engine according to claim 1, wherein said cover member when formed as a water-cooled internal combustion engine is formed integrally with a thermostat case. 3. The cooling structure for an internal combustion engine according to claim 1, wherein the cover member in the case of a water-cooled internal combustion engine is formed integrally with a spark plug holder. 4. An air inlet opening on one surface of the cylinder block in communication with an air jacket around the cylinder bore and facing the upstream side of the blower, and communicating with the outside of the cylinder jacket from the air jacket on the other surface of the cylinder block. An air-cooled internal combustion engine comprising: an open air outlet, wherein air introduced into the air inlet flows through the air jacket, cools around a cylinder bore, and is drawn out from the air outlet and the like. The cooling structure for an internal combustion engine according to claim 1. 5. The internal combustion engine according to claim 4, wherein a fan cover for supporting the blower fan covers at least one surface of the cylinder block, and the blower fan is disposed so as to face the air inlet. Cooling structure.