JP7195203B2 - internal combustion engine - Google Patents

Description

The present invention relates to internal combustion engines.

2. Description of the Related Art A water pump is known that includes a drain passage that communicates with an internal space (see, for example, Patent Document 1 below). 2. Description of the Related Art An engine is known that includes a water pump that is arranged in the axial direction of a camshaft that includes an intake cam and an exhaust cam (see, for example, Patent Document 2 below).
[Prior art documents]
[Patent Literature]
[Patent Document 1] JP-A-2002-115546 [Patent Document 1] JP-A-2015-10551

It is desirable that the bearing portion is provided with an opening serving as an oil supply passage for supplying lubricating oil to the bearing. Further, it is desirable that the oil seal portion is provided with an opening for discharging oil, water, dust, etc. accumulated outside. However, there is a problem that it takes a lot of man-hours to form openings in different places.

In order to solve the above problems, the internal combustion engine according to claim 1 has a water pump arranged coaxially with a shaft that rotates with the rotation of the crankshaft. The water pump housing has a bearing portion in which a bearing that rotatably supports a rotating member that rotates the impeller of the water pump is arranged, and an oil seal portion that seals oil in the internal combustion engine. , the bearing portion and the oil seal portion are provided with coaxial openings.

In the internal combustion engine according to claim 2, the opening is inclined with respect to an axis perpendicular to the rotation axis of the impeller.

In the internal combustion engine according to claim 3, the opening provided in the bearing portion is provided so as to incline upward toward the inside of the internal combustion engine, and the opening provided in the oil seal portion extends into an outside air space. It is provided so as to incline downward.

In the internal combustion engine according to claim 4, the bearing portion is provided with two or more bearings, and the opening of the bearing portion is provided to open toward the space between the bearings. It is

In the internal combustion engine according to claim 5, the water pump is supported by a cylinder head and a stay extending from the cylinder head, and the stay is arranged so as to at least partially overlap the housing when viewed from the cylinder axis. .

In the internal combustion engine according to claim 6, the driven gear for driving the water pump is provided with a concave portion at a center portion in a radial direction of a shaft portion for driving the water pump, and the driven gear is fitted with the shaft portion. The bearing that rotatably supports the rotating member is arranged so as to overlap the recess in the axial direction of the driven gear.

According to the internal combustion engine of claim 1, by providing the opening coaxially formed in the housing in the bearing portion and the oil seal portion, the oil can be supplied to the bearing portion and the oil seal portion can be used as a drain hole. It is possible to reduce the processing man-hours of the opening having the function of

According to the internal combustion engine of claim 2, by inclining the opening, the bearing portion and the oil seal portion can be arranged along the rotation axis of the impeller, thereby suppressing an increase in size in the radial direction. can be done.

According to the internal combustion engine of claim 3, since the opening of the bearing portion is open upward, the oil in the internal combustion engine can be effectively supplied. In addition, since the opening of the oil seal is inclined downward toward the outside air space, water can be drained efficiently. can be opened to the outside air.

According to the internal combustion engine of claim 4, by providing the oil supply port in the space between the bearings, it is possible to effectively supply oil to the bearings on both sides.

According to the internal combustion engine of claim 5, since the stay and the water pump housing are arranged so that at least a part thereof overlaps when viewed from the cylinder axis, the size of the internal combustion engine can be reduced.

According to the internal combustion engine of claim 6, since the recess provided in the driven gear and the bearing that supports the shaft of the driven gear overlap in the axial direction of the driven gear, the internal combustion engine can be downsized.

It should be noted that the above summary of the invention does not list all the necessary features of the invention. Subcombinations of these feature groups can also be inventions.

1 is a side view schematically showing a motorcycle 10 of a first embodiment; FIG. 2 shows the appearance of the engine 20. FIG. The internal structure of the first cylinder head 26 is shown. 6 is a cross-sectional view taken along a plane perpendicular to the camshaft axial direction of the rotation reduction mechanism 60 including the driving gear 61, the intermediate gear 62, and the driven gear 63. FIG. A section of the drive gear 61 is shown. (top view of cylinder axis) A cross section of the intermediate gear 62 is shown. (AA cross section: see Fig. 3) 4 is a perspective view showing the appearance of a first cam holder 64; FIG. A cross-sectional view of the driven gear 63 and the water pump 40 is shown. (BB cross section: see Fig. 2) 6 is a diagram showing meshing of a drive gear 61, an intermediate gear 62 and a driven gear 63; FIG. 4 shows a cross-sectional view of the meshing portion between the shaft portion 80 of the driven gear 63 and the shaft portion 102 of the water pump 40. FIG. (C-C cross section: see FIG. 8) 4 is a diagram showing an appearance of a stay 32; FIG. FIG. 3 is a view of the mounting portion of the water pump 40 and the first cylinder head 26 as viewed from above along the cylinder axis AX. A first cam holder 564a and a first cam holder 564b as modified examples of the first cam holder 64 are shown.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential for the solution of the invention. In addition, in the drawings, the same or similar parts may be denoted by the same reference numerals to omit redundant description.

FIG. 1 is a side view schematically showing a motorcycle 10 of the first embodiment. A motorcycle 10 includes an engine 20 , a main frame 1 , front wheels 4 and rear wheels 6 . Engine 20 includes crankcase 11 , first cylinder bank 21 , second cylinder bank 22 , oil pan 15 and water pump 40 .

In this embodiment, the direction from the rear wheel 6 to the front wheel 4 may be called the front, and the direction from the front wheel 4 to the rear wheel 6 may be called the rear. The left hand when facing the front wheel 4 from the rear wheel 6 is sometimes called the left, and the right hand when facing the front wheel 4 from the rear wheel 6 is sometimes called the right. The left-right direction is the vehicle width direction of the motorcycle 10 . The direction toward the ground when the front wheels 4 and the rear wheels 6 of the motorcycle 10 are in contact with the ground is sometimes called the downward direction, and the opposite direction to the downward direction is sometimes called the upward direction.

The front fork 2 is provided at the front end of the main frame 1 of the motorcycle 10 so as to be able to turn left and right. A steering handle 3 is attached to the upper end of the front fork 2 integrally with the front fork 2 . The front wheel 4 is rotatably supported under the front forks 2 .

The swing arm 5 is provided at the rear portion of the main frame 1 so as to be vertically swingable. A rear wheel 6 is rotatably supported at the rear end of the swing arm 5 . The rear wheel 6 is rotationally driven by the power from the engine 20 via the drive chain 7 . A fuel tank 8 is placed above the front portion of the main frame 1 . A seat 9 is provided behind the fuel tank 8 .

The radiator 18 cools the cooling water circulating between the engine 20 and the running wind. An exhaust pipe 25 is attached to the engine 20 . The exhaust pipe 25 is connected to the exhaust muffler 19 .

FIG. 2 shows the appearance of the engine 20. As shown in FIG. Engine 20 is an example of an internal combustion engine. Engine 20 is a V-type engine. Engine 20 is a four-cylinder engine. The engine 20 is a DOHC four-stroke engine.

The first cylinder bank 21 and the second cylinder bank 22 are positioned above the crankcase 11 . The oil pan 15 is attached below the crankcase 11 .

The first cylinder bank 21 is a cylinder bank arranged on the front side of the engine 20 . The second cylinder bank 22 is a cylinder bank arranged on the rear side of the engine 20 . The first cylinder bank 21 has two cylinders in the vehicle width direction. The second cylinder bank 22 has two cylinders in the vehicle width direction.

The first cylinder bank 21 has a first cylinder block 24 , a first cylinder head 26 and a first head cover 27 . The first cylinder block 24 extends forward and upward from the crankcase 11 . A first cylinder head 26 is attached to the first cylinder block 24 . An exhaust pipe 25 connected to the exhaust muffler 19 is connected to the first cylinder head 26 . The first head cover 27 is attached to the first cylinder head 26 .

The second cylinder bank 22 includes a second cylinder block 28 , a second cylinder head 29 and a second head cover 31 . The second cylinder head 29 is attached to the second cylinder block 28 .

In the crankcase 11, there are a crankshaft that is rotationally driven by the forward and backward movement of the pistons provided in the first cylinder bank 21 and the second cylinder bank 22, and a transmission that rotates the sprocket 17 by changing the rotation of the crankshaft. Prepare. A drive chain 7 is wound around the sprocket 17 , and the sprocket 17 rotates the rear wheel 6 through the drive chain 7 . In this embodiment, the crankshaft inside the crankcase 11 is called "crankshaft".

A water pump 40 is attached to the first cylinder head 26 . The water pump 40 includes a pump-side stay 41 and a pump-side stay 42 for attaching the water pump 40 to the first cylinder head 26 . The pump-side stay 42 is fastened to the stay 32 extending from the first cylinder head 26 . The water pump 40 circulates coolant for the engine 20 . The cooling water circulated by the water pump 40 circulates between the engine 20 and the radiator 18 that cools the cooling water.

FIG. 3 shows the internal structure of the first cylinder head 26. As shown in FIG. FIG. 3 shows a state in which the first head cover 27 is removed. The first cylinder head 26 includes a first cam gear 53 , a second cam gear 54 , a first camshaft 51 , a second camshaft 52 , a rotation reduction mechanism 60 , a first cam holder 64 and a second cam holder 65 . and a third cam holder 66 are provided. The rotation reduction mechanism 60 is driven as the camshaft of the engine 20 rotates. The rotation reduction mechanism 60 includes a drive gear 61 , an intermediate gear 62 and a driven gear 63 .

The first cam gear 53 and the second cam gear 54 are connected to the crankshaft via gear trains. Rotation of the crankshaft is transmitted to the first cam gear 53 and the second cam gear 54 via the gear train. The first cam gear 53 and the second cam gear 54 rotate once every two rotations of the crankshaft.

A first cam gear 53 is connected to one end of the first camshaft 51 . A rotating shaft of the first cam gear 53 is provided coaxially with the first camshaft 51 . A second cam gear 54 is connected to one end of the second camshaft 52 . A rotation axis of the second cam gear 54 is provided coaxially with the second camshaft 52 .

The first cam holder 64 , the second cam holder 65 , and the third cam holder 66 are fixed to the first cylinder head 26 . , and the first cam holder 64 is fastened to the first cylinder head 26 . As a result, the first cam holder 64 presses the first cam shaft 51 and the second cam shaft 52 against the cam shaft bearing portion (not shown) of the first cylinder head 26, and the first cam shaft 51 and the second cam shaft 52 are pushed together. is rotatably supported. Thus, the first camshaft 51 and the second camshaft 52 are supported by the first cam holder 64 , the second cam holder 65 and the third cam holder 66 .

The first camshaft 51 rotates through the first cam gear 53 in synchronization with the rotation of the crankshaft. The second camshaft 52 rotates through the second cam gear 54 in synchronization with the rotation of the crankshaft. The first camshaft 51 and the second camshaft 52 are shafts that rotate as the crankshaft rotates.

The first camshaft 51 rotates in synchronization with the rotation of the crankshaft to open and close the intake port of the intake port. The second camshaft 52 rotates in synchronization with the rotation of the crankshaft to open and close the exhaust port. Specifically, when the first camshaft 51 rotates, the rocker arm swings, and the tappet screw opens and closes the intake valve. Further, the rotation of the second camshaft 52 swings the rocker arm, and the tappet screw opens and closes the exhaust valve.

A plug insertion cylinder 58 is provided between the first camshaft 51 and the second camshaft 52 . A spark plug 59 for igniting a cylinder of the engine 20 is inserted into the plug insertion cylinder 58 .

A driving gear 61 is connected to the end of the first camshaft 51 opposite to the end to which the first cam gear 53 is connected. The drive gear 61 is connected to a driven gear 63 via an intermediate gear 62 . The intermediate gear 62 is supported by the first cam holder 64 via a shaft member 70 . The intermediate gear 62 is located between the first camshaft 51 and the second camshaft 52 when viewed in the camshaft axial direction. Therefore, when viewed in the axial direction of the camshaft, the intermediate gear 62 is provided at a position overlapping the plug insertion cylinder 58 .

FIG. 4 is a cross-sectional view of a rotation reduction mechanism 60 including a drive gear 61, an intermediate gear 62, and a driven gear 63. FIG. FIG. 4 is a cross-sectional view taken along a plane orthogonal to the axial direction of the camshaft, showing an embodiment of the first head cover 27 of the first cylinder head 26, the body portion 300, the spark plug mounting portion 34, and the spark plug cover 35. FIG. 3 is a diagram shown together with FIG. As can be seen from FIGS. 3 and 4 , the rotation reduction mechanism 60 is surrounded by the body portion 300 of the first cylinder head 26 and the first head cover 27 . That is, the rotation speed reduction mechanism 60 is provided inside the first cylinder head 26 . Further, when viewed in the axial direction of the camshaft, the intermediate gear 62 overlaps the spark plug mounting portion 34 .

The drive gear 61 meshes with the intermediate gear 62 . The intermediate gear 62 meshes with the driven gear 63 . Thereby, the rotation of the first camshaft 51 is transmitted to the driven gear 63 via the driving gear 61 and the intermediate gear 62 . The driven gear 63 is a gear with a larger diameter than the driving gear 61 . As will be described later, the driven gear 63 is connected to the impeller of the water pump 40 . Thus, the rotation of the first camshaft 51 is transmitted to the impeller of the water pump 40 via the rotation reduction mechanism 60 including the drive gear 61 , the intermediate gear 62 and the driven gear 63 .

The driven gear 63 is provided coaxially with the second camshaft 52 . The driven gear 63 is not directly connected with the second camshaft 52 . The driven gear 63 is not in contact with the second camshaft 52 .

The water pump 40 is arranged along the central axis of the second camshaft 52 . Water pump 40 is driven by rotation of driven gear 63 . The water pump 40 circulates a coolant that cools the first cylinder block 24 , the first cylinder head 26 , the second cylinder block 28 and the second cylinder head 29 .

As shown in FIGS. 3 and 4, the drive gear 61, the intermediate gear 62, and the driven gear 63 are arranged in a row in the direction in which the first camshaft 51 and the second camshaft 52 are arranged. That is, the driving gear 61 , the intermediate gear 62 , and the driven gear 63 are provided so as to overlap each other in the axial direction of the first camshaft 51 and the second camshaft 52 . As a result, it is possible to prevent the first cylinder head 26 from increasing in size in the axial direction of the camshaft.

Further, the drive gear 61 and the driven gear 63 are connected by an intermediate gear 62 . As a result, it is not necessary to directly mesh the driving gear 61 and the driven gear 63 in order to form the rotation reduction mechanism, and the degree of freedom in layout can be improved. Moreover, since the drive gear 61 and the driven gear 63 can be prevented from increasing in diameter, the first cylinder head 26 can be prevented from increasing in size.

FIG. 5 shows a cross section of the drive gear 61 . The drive gear 61 is provided coaxially with the first camshaft 51 . The drive gear 61 is directly connected to the first camshaft 51 . Specifically, the drive gear 61 is spline-connected to the outer circumference of the first camshaft 51 . The drive gear 61 rotates at the same rotational speed as the first camshaft 51 .

FIG. 6 shows a cross section of the intermediate gear 62 . The intermediate gear 62 is rotatably supported by the shaft member 70 . The shaft member 70 is supported by the first cam holder 64 . The gear portion 72 of the intermediate gear 62 meshes with the gear portion of the driving gear 61 . Also, the gear portion 72 meshes with the gear portion of the driven gear 63 . The intermediate gear 62 is an example of a gear member as an intermediate member connecting the driving gear 61 and the driven gear 63 .

FIG. 7 is a perspective view showing the appearance of the first cam holder 64. As shown in FIG. The first cam holder 64 has a support portion 74 . The support portion 74 supports the intermediate gear 62 . The support portion 74 is part of the integrally molded first cam holder 64 . That is, the support portion 74 is provided integrally with the first cam holder 64 . In this manner, the support portion 74 of the intermediate gear 62 is provided integrally with the holder of the first cam holder 64, so the number of parts can be reduced.

The support portion 74 is formed with an opening (73) into which the shaft member 70 is inserted. An opening 75 is formed in the upper surface of the support portion 74 . A retaining recess 77 is formed radially outward of the shaft member 70 , and is supported by inserting a support member 76 into the opening 75 and the retaining recess 77 . The support member 76 is a pin-shaped member. Thereby, the shaft member 70 is non-rotatably fixed to the first cam holder 64 by the support member 76 .

As described above, the support portion 74 has an opening 75 facing radially outward of the shaft member 70 , and the support member 76 can be inserted through the opening 75 to prevent the shaft member 70 from slipping off. A support member 76 fits and secures the shaft member 70 . Therefore, the shaft member 70 that supports the intermediate gear 62 can be fixed and retained with a simple structure.

The support portion 74 is positioned above the axis AX1 of the first camshaft 51 and the axis AX2 of the second camshaft 52 on the cylinder axis AX. Thus, since the support portion 74 is positioned above the camshaft on the cylinder axis, a sufficient space for disposing other members can be secured below the first cam holder 64 .

The support portion 74 of the intermediate gear 62 is adjacent to the fastening portion 68 of the first cam holder 64 . Since the fastening portion 68 of the first cam holder 64 is provided at a position adjacent to the support portion 74 in this way, the support portion 74 can be firmly fixed.

The first cam holder 64 has a through hole 78 through which the plug insertion tube 58 passes. Since the intermediate gear 62 is supported by the support portion 74 , the intermediate gear 62 is provided at a position overlapping the through hole 78 when viewed in the axial direction of the camshaft. In this manner, the intermediate gear 62 is provided at a position overlapping the mounting portion of the spark plug 59 .

FIG. 8 shows a cross-sectional view of driven gear 63 and water pump 40 . FIG. 9 shows the engagement of drive gear 61, intermediate gear 62 and driven gear 63. FIG. FIG. 9 shows a DD section of FIG.

The driven gear 63 includes a shaft portion 80 and a gear portion 82 . The water pump 40 has a housing 104 , an impeller 100 and a shaft portion 102 . The shaft portion 102 is provided coaxially with the driven gear 63 . The shaft portion 102 is fitted with the shaft portion 80 of the driven gear 63 . Specifically, the shaft portion 80 of the driven gear 63 is fitted to the inner circumference of the shaft portion 102 . Axial portion 102 is a rotating member that rotates impeller 100 .

A bearing portion 92 comprising a bearing 90a and a bearing 90b is arranged in the housing 104 . Bearing 90 a and bearing 90 b are provided between the circumference of shaft 102 and the inner surface of housing 104 . In the direction of the axis AX2 of the second camshaft 52, the bearing 90b is provided closer to the impeller 100 than the bearing 90a. In the radial direction, bearings 90 a and 90 b are provided between shaft portion 102 and the inner wall of housing 104 . The bearing 90a and the bearing 90b may be generically called "bearing 90."

The bearing 90 rotatably supports the rotating member that fits with the shaft. Bearing 90 rotatably supports shaft portion 102 . An impeller 100 is fixed to the shaft portion 102 . The impeller 100 is fixed to the end of the shaft portion 102 of the water pump 40 opposite to the side where the shaft portion 80 of the driven gear 63 is provided.

The driven gear 63 is provided coaxially with the second camshaft 52 . A shaft portion 80 of the driven gear 63 is not in contact with the second camshaft 52 . As such, the driven gear 63 is not in contact with the second camshaft 52 .

The driven gear 63 is provided with an extending portion 84 extending in the axial direction of the second camshaft 52 . The extended portion 84 of the driven gear 63 overlaps with a hollow portion 87 provided in the second camshaft 52 in the axial direction of the second camshaft 52 . Thus, the driven gear 63 has an extension portion 84 that extends into a hollow portion 87 provided in the second camshaft 52 . Therefore, when the water pump 40 is removed from the engine 20 or when the water pump 40 is assembled, the extending portion 84 is supported by the hollow portion 87 and the position of the driven gear 63 can be held.

A shaft portion 80 of the driven gear 63 drives an impeller 100 included in the water pump 40 . The driven gear 63 is provided with a concave portion 83 recessed in the axial direction of the second camshaft 52 with the shaft portion 80 as the center. A bearing 90 that rotatably supports the shaft portion 80 is arranged so as to overlap the recessed portion 83 in the axial direction of the second camshaft 52 . Thus, the recess 83 provided in the driven gear 63 and the bearing 90 that supports the shaft of the driven gear 63 are arranged so as to overlap in the vehicle width direction (axial direction of the driven gear 63). As a result, the entire engine 20 including the water pump 40 can be downsized.

The first camshaft 51 is a camshaft for opening and closing the intake port of the intake port. The second camshaft 52 is a camshaft for opening and closing the exhaust port of the exhaust port. In general, the axial length of the camshaft for opening and closing the exhaust port can be shorter than the axial length of the camshaft for opening and closing the intake port. Therefore, there is a space for forming the recess 83 on the second camshaft 52 side. According to the engine 20, by arranging a portion of the bearing 90 in the recess 83, the space on the second camshaft 52 side can be effectively used.

An oil seal portion 120 a and an oil seal portion 120 b are provided between the housing 104 and the shaft portion 102 . The oil seal portion 120 a is provided closer to the impeller 100 than the bearing 90 in the direction of the axis AX2 of the second camshaft 52 . The oil seal portion 120b is provided closer to the impeller 100 than the oil seal portion 120a in the direction of the axis AX2 of the second camshaft 52 .

The oil seal portion 120 a and the oil seal portion 120 b seal the oil in the engine 20 and the coolant of the water pump 40 . The oil seal portion 120a prevents the oil in the engine 20 from being discharged to the outside. The oil whose discharge is suppressed can serve as lubricating oil for the bearing portion 92 . The oil seal portion 120b mainly suppresses the cooling water from being discharged from the water pump 40 to the outside. The oil seal portion 120a and the oil seal portion 120b may be collectively referred to as "oil seal portion 120".

An opening 111 and an opening 112 are provided in the bearing portion 92 and the oil seal portion 120 . Specifically, the bearing portion 92 is provided with an opening portion 111 . An opening 112 is provided in the oil seal portion 120 . The opening 111 and the opening 112 are provided coaxially. The openings 111 and 112 are inclined with respect to the axis perpendicular to the shaft 102 of the impeller 100 .

An opening 111 provided in the bearing portion 92 is inclined upward toward the inside of the engine 20 . The opening 112 provided in the oil seal portion 120 is provided so as to incline downward toward the outside air space. Two or more bearings 90 are provided in the bearing portion 92, and the opening portion 111 of the bearing portion 92 is provided so as to open toward the space between the plurality of bearings 90 arranged. Specifically, the opening 111 is provided so as to open toward the space between the bearing 90a and the bearing 90b.

According to the engine 20 , the openings 111 and 112 coaxially formed in the housing 104 are provided in the bearing portion 92 and the oil seal portion 120 . Therefore, in the bearing portion 92, oil can be supplied from the opening portion 111 to the bearing portion 92, and in the oil seal portion 120, the opening portion 111 can remove oil, water, dust, etc. accumulated near the oil seal portion 120 to the outside. It functions as a drain hole for draining water. Since the opening 111 and the opening 112 are provided coaxially, the opening 111 and the opening 112 can be formed simultaneously by one machining.

The axes of the openings 111 and 112 are inclined with respect to the axis perpendicular to the axis of the shaft 102 . Therefore, even when the bearing portion 92 and the oil seal portion 120 are arranged along the axis of the shaft portion 102, the bearing portion 92 and the oil seal portion 120 can be simultaneously formed by one machining.

Since the opening 111 of the bearing portion 92 is open upward, the oil in the engine 20 can be efficiently supplied to the bearing portion 92 . In addition, since the opening 112 of the oil seal portion 120 is inclined downward toward the outside air space, water can be drained efficiently from the opening 112 . Further, even if the housing 104 is arranged close to the engine 20, the opening 112 of the oil seal portion 120 can be exposed to the outside air.

Since the opening 111 is provided between the position where the bearing 90a is arranged and the position where the bearing 90b is arranged, it is possible to effectively supply oil to the bearings 90 on both sides from the single opening 111. .

FIG. 10 shows a cross-sectional view of the meshing portion between the shaft portion 80 of the driven gear 63 and the shaft portion 102 of the water pump 40 . A shaft portion 80 of the driven gear 63 has a plane portion 81 on a surface facing the shaft portion 102 of the water pump 40 . A shaft portion 102 of the water pump 40 has a plane portion 101 on a surface facing the driven gear 63 . The impeller 100 rotates when the plane portion 81 of the shaft portion 80 of the driven gear 63 and the plane portion 101 of the shaft portion 102 of the water pump 40 mesh with each other.

As described above, the engine 20 has a structure that rotates the impeller 100 of the water pump 40 coaxially and in the same direction as the second camshaft 52 . Further, the rotation of the first camshaft 51 can be transmitted to the impeller 100 via a rotation reduction mechanism including the drive gear 61, the intermediate gear 62 and the driven gear 63 to rotate the impeller 100. As shown in FIG. According to the engine 20, by adjusting the gear ratio between the driving gear 61 and the driven gear 63, the rotation speed of the impeller 100 can be designed to an appropriate value. This allows the impeller 100 to be designed to rotate at a suitable speed less than 1/2 the crankshaft speed. Therefore, the stirring friction of the impeller 100 can be reduced. In addition, since the impeller 100 can be arranged on the extension line of the second camshaft 52, based on the design of the drive system in which the impeller 100 is directly rotated by the second camshaft 52, the design of piping can be minimized. can respond. If a coupling joint that couples the second camshaft 52 and the shaft portion 102 is provided instead of the driven gear 63 , the drive system can be changed to one in which the impeller 100 is directly rotated by the second camshaft 52 .

FIG. 11 is a diagram showing the appearance of the stay 32. As shown in FIG. FIG. 12 is a top view of the mounting portion of the water pump 40 and the first cylinder head 26 along the cylinder axis AX.

The first cylinder head 26 includes a cylinder head side first mounting portion 301 on a body portion 300 of the first cylinder head 26 . The stay 32 is attached so as to extend from the body portion 300 of the first cylinder head 26 toward the first head cover 27 . The stay 32 is provided with a cylinder head side second mounting portion 302 .

The water pump 40 is provided with a water-pump-side first mounting portion 401 at the tip of the pump-side stay 41 . The water pump 40 is provided with a water-pump-side second mounting portion 402 at the tip of the pump-side stay 42 . The water pump 40 is fastened to the first cylinder head 26 by fastening members 411 and 412 .

Specifically, the water pump side first mounting portion 401 of the pump side stay 41 is fastened together with the cylinder head side first mounting portion 301 of the first cylinder head 26 and the housing 104 in the vehicle width direction. A water pump side second attachment portion 402 of the pump side stay 42 is fastened together in the vehicle width direction with a cylinder head side second attachment portion 302 at the tip of the stay 32 attached to the first cylinder head 26 and the housing 104. . Thus, the stay 32 is arranged so as to at least partially overlap the housing 104 when viewed from the cylinder axis, and the water pump 40 is supported by the first cylinder head 26 by the stay 32 extending from the first cylinder head 26 . Since the stay 32 and the housing 104 are arranged so that at least a part thereof overlaps when viewed from the cylinder axis, the size of the engine 20 can be reduced.

13 shows a first cam holder 564a and a first cam holder 564b as modifications of the first cam holder 64. FIG. FIG. 13 shows the internal structure of the first cylinder head 26 and corresponds to FIG. The first cam holder 564 a supports the first cam shaft 51 and the second cam shaft 52 , and the first cam holder 564 b supports the first cam shaft 51 .

Similar to the first cam holder 64, each of the first cam holders 564a and 564b is provided with an opening into which the shaft of the intermediate gear 62 is inserted. One of the shafts of the intermediate gear 62 in the axial direction is supported by the opening of the first cam holder 564a, and the other of the shafts of the intermediate gear 62 in the axial direction is supported by the opening of the first cam holder 564b. Thereby, the intermediate gear 62 is provided so as to be sandwiched between the first cam holder 564a and the first cam holder 564b, and is supported between the first cam holder 564a and the first cam holder 564b.

The impeller 100 of the water pump 40 described above is an example of a functional member driven by a camshaft. Various members other than the impeller can be applied as the functional member driven by the camshaft. Further, the method of driving the impeller 100 is not limited to the method of rotating the first camshaft 51 at a reduced speed. The impeller 100 may be connected to the second camshaft 52 and driven at the same rotational speed as the second camshaft 52 . The first camshaft 51 and the second camshaft 52 are examples of shafts that rotate as the crankshaft rotates. Impeller 100 may transmit rotation from any shaft that rotates with rotation of the crankshaft.

The structure of the engine 20 has been described above using the embodiment of the motorcycle. However, the structure of the engine 20 can be applied to engines of saddle type vehicles other than motorcycles. For example, the structure of the engine 20 can be applied to a three-wheel saddle-riding vehicle and a four-wheel saddle-riding vehicle. The structure of the engine 20 is not limited to a saddle-ride type vehicle, and can be applied to any engine structure of transportation equipment.

Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various modifications and improvements can be made to the above embodiments. In addition, matters described with respect to a specific embodiment can be applied to other embodiments as long as they are not technically inconsistent. It is clear from the description of the scope of claims that forms with such modifications or improvements can also be included in the technical scope of the present invention.

1 main frame, 2 front fork, 3 steering wheel, 4 front wheel, 5 swing arm, 6 rear wheel, 7 drive chain, 8 fuel tank, 9 seat, 10 motorcycle, 11 crankcase, 15 oil pan, 17 sprocket, 18 radiator 19 exhaust muffler 20 engine 21 first cylinder bank 22 second cylinder bank 24 first cylinder block 25 exhaust pipe 26 first cylinder head 27 first head cover 28 second cylinder block 29 second cylinder head 31 second head cover 32 Stay 34 Spark plug mounting portion 35 Spark plug cover 40 Water pumps 41, 42 Pump-side stay 51 First camshaft 52 Second camshaft 53 First cam gear 54 Second cam gear 58 Plug insertion cylinder 59 Spark plug 60 Rotation reduction Mechanism 61 Drive gear 62 Intermediate gear 63 Driven gear 64 First cam holder 65 Second cam holder 66 Third cam holder 68 Fastening portion 69 Fastening member 70 Shaft member 72 Gear portion 73 Opening 74 Supporting portion 75 Opening 76 Support Member 77 Retaining concave portion 78 Through hole 80 Shaft portion 81 Flat portion 82 Gear portion 83 Concave portion 84 Extension portion 87 Hollow portions 90a, 90b Bearing 92 Bearing portion 100 Impeller 101 Flat portion 102 Shaft portion 104 Housing 111, 112 Opening 120 Oil seal portion 300 Body portion 301 Cylinder head side first mounting portion 302 Cylinder head side second mounting portion 401 Water pump side first mounting portion 402 Water pump side second mounting portions 411, 412 Fastening member 564 First cam holder

Claims (5)

In an internal combustion engine (20) in which a water pump (40) is arranged coaxially with a shaft (51) that rotates with rotation of a crankshaft,
A housing (104) of the water pump (40) is provided with bearings (90a, 90b) that rotatably support a rotating member (102) that rotates the impeller (100) of the water pump (40). a part (92) and an oil seal part (120) for sealing oil in the internal combustion engine,
The bearing portion (92) is provided with a first opening (111) for supplying oil into the bearing portion (92), and the oil seal portion (120) is provided with the oil seal portion (120). A second opening (112) is provided for draining water from the
The first opening (111) is provided coaxially with the second opening (112),
The bearing part (92) is provided with two or more bearings (90a, 90b), and the first opening (111) is in the space between the bearings (90a, 90b). An internal combustion engine that is provided so as to open toward it . 2. The internal combustion engine of claim 1, wherein said first opening (111 ) and said second opening ( 112) are inclined with respect to an axis perpendicular to the axis of rotation of said impeller (100). internal combustion engine. 3. The internal combustion engine according to claim 2, wherein the first opening (111) is inclined upward toward the inside of the internal combustion engine (20), and the second opening (112) is open to outside air. An internal combustion engine that is provided so as to incline downward toward space. 4. The internal combustion engine according to claim 1 , wherein said water pump (40) is supported by a cylinder head (26) and a stay (32) extending from said cylinder head (26), said stay (32) is an internal combustion engine arranged so as to at least partially overlap the housing (104) when viewed from the cylinder axis. 5. The internal combustion engine according to claim 1 , wherein the driven gear (63) for driving the water pump (40) comprises a shaft (80) for driving the water pump (40) and the A recess (83) is provided around the shaft (80), and the bearings (90a, 90b) for rotatably supporting the rotating member (102) fitted with the shaft (80) are provided. An internal combustion engine arranged so as to overlap with the recess (83) in the rotational axis direction of the driven gear (63).

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