JPS6336404B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water-cooled engine for, for example, a two-wheeled motor vehicle.

Modern motorcycles tend to have water-cooled engines in order to maintain stable output while driving, and are widely used not only in racing motorcycles such as Motokurosa but also in general motorcycles. It is becoming popular.

By the way, when the engine is water-cooled, it is necessary to circulate engine cooling water between the engine and the radiator, so it is necessary to provide a water pump on the engine side for pumping the cooling water.
In this case, the water pump will be installed in the crankcase, but since various functional parts such as the oil pump, clutch, and transmission mechanism are housed within the crankcase, the installation location of the water pump is quite limited. will receive. For this reason, if the water pump is installed on the upper side of the crankcase, avoiding the clutch and oil pump, if the engine cooling water in this pump is drained by removing the drain bolt, the engine cooling water will adhere to the crankcase and cause the crankcase to drain. There is a problem with the case becoming dirty. For this reason, if the water pump is provided on the lower side of the crankcase, there will be problems such as the minimum ground clearance of the engine will be low, making it unsuitable for driving on rough roads or rough terrain.

The present invention was developed based on the above circumstances, and its purpose is to prevent the engine cooling water from directly splashing onto the engine even when the engine cooling water in the water pump is drained. It is an object of the present invention to provide a water-cooled engine which can prevent the water pump from protruding significantly below the engine, and which can ensure the necessary and sufficient minimum ground clearance of the engine.

That is, in order to achieve the above object, the present invention
An oil pump and a clutch housing are arranged side by side along the front and back direction on one side of the crankcase, and a water pump is arranged in a lower space located between these oil pumps and the clutch housing. The pump, the clutch housing, and the water pump are arranged in a triangular positional relationship when viewed from one side of the crankcase.

The present invention will be explained below based on an embodiment shown in the drawings.

1 in the figure is the frame of a motorcycle, and 1 on the left and right
A pair of down tubes 2, 2 are provided. An engine 3 is mounted on these down tubes 2,2. The engine in this embodiment is a water-cooled two-stroke single-cylinder engine, and includes a cylinder 5 on the upper surface of the front end of a crankcase 4. Crankcase covers 6, 6 (only one is shown) are attached to both side surfaces of the crankcase 4, and a cylinder 5 and a crank chamber (not shown) are attached to the front end side of one crankcase cover 6. An oil pump 8 is attached that pumps lubricating oil into the intake passage of the carburetor 7. A clutch 9 is disposed at the rear end of one side of the crankcase 4 located behind the oil pump 8. The sides of the oil pump 8 and the clutch 9 are covered by an oil pump cover 10 and a clutch housing 11 that are attached to the sides of the crankcase cover 6. It protrudes laterally beyond the side surface of the case cover 6.

On the other hand, a water pump 12 is attached to the crankcase cover 6.
2 is located in the lower part 13 narrowed by the oil pump cover 10 and the clutch housing 11. Regarding this water pump 12,
It is detailed in the figure. That is, a mounting port 14 is formed in the lower portion 13 of the crankcase cover 6, and a housing cover 16 is fluid-tightly mounted to the periphery of the opening of the mounting port 14 via a gasket 15. And the above crankcase cover 6
The inside of the mounting port 14 is separated from the crankcase 4 side by a partition wall 17, and a pump chamber 18 is formed by the partition wall 17 and the inner surface of the housing cover 16. Therefore,
The housing cover 16 is the oil pump cover 10
The oil pump cover 10, the clutch housing 11, and the housing cover 16 have a substantially triangular shape when viewed from the side. are arranged in the positional relationship of the vertices of. By the way, an impeller shaft 20 is attached to the partition wall 17 through an oil seal 19. At the tip of the impeller shaft 20 facing the pump chamber 18, there is an impeller 2.
1 is installed, and the crankcase 4
A drive gear 22 for rotationally driving the impeller shaft 20 is attached to the side penetrating end.
Further, a drain hole 23 for draining engine cooling water in the pump chamber 18 is formed through the lower part of the housing cover 16.
A drain bolt 24 is loosely inserted into the drain bolt 24, and its insertion end is screwed into a screw hole 25 of the crankcase cover 6. Therefore, this drain bolt 24 also has the function of fixing the housing cover 16 to the crankcase cover 6. Further, a connecting pipe section 26 connected to the pump chamber 18 is led out from the end surface of the housing cover 16, and the open end of this connecting pipe section 26 is connected to the lower part of the radiator 27 attached to the rear side of the down tubes 2, 2. is connected to via a first cooling water pipe 28. Furthermore, a cooling water passage 29 facing the cylinder 5 side is integrally formed on the inner surface of the crankcase cover 6, and a lower end of this cooling water passage 29 is connected to the pump chamber 18. One end of a second cooling water pipe 31 is fluid-tightly connected to the upper end opening of this cooling water passage 29 through an O-ring 30, and the other end of this second cooling water pipe 31 is It is connected to the side surface of the cylinder 5 and continues to the water jacket inside the cylinder 5. Furthermore, a third cooling water outlet 33 at the top of the cylinder head 32 has a
One end of the third cooling water pipe 34 is connected to the third cooling water pipe 34, and the other end of this third cooling water pipe 34 is connected to the radiator 27.
connected to the top of the. Therefore, the engine cooling water radiated by the radiator 27 is transferred to the impeller 2.
As the impeller 21 rotates, the water is sucked into the pump chamber 18 through the first cooling water pipe 28, and the pressure is gradually increased as the impeller 21 rotates.
The coolant is discharged from the coolant into the coolant passage 29, from where it is forced into the water jacket of the cylinder 5 through the second coolant pipe 31. This pressure-fed engine cooling water flows through the water jackets of the cylinder 5 and the cylinder head 32 to cool them, and then returns to the radiator 27 through the third cooling water pipe 34, where the heat is radiated. It will be done.

However, according to this configuration, the water pump 12 is disposed below between the clutch 9 and the oil pump 8 and is located at the lowest part of the crankcase cover 6, making it easy to attach and detach the drain bolt 24. Of course, drain hole 2
Even when the engine cooling water in the pump chamber 18 is drained from the pump chamber 3, the engine cooling water does not adhere to other parts of the crankcase 4, such as the clutch housing 11 and the oil pump cover 10. Therefore, during maintenance and inspection of the cooling water circulation system, the crankcase 4 and its vicinity are not contaminated.

Furthermore, since the water pump 12 is located between the clutch housing 11 and the oil pump cover 10 from below, the limited space can be used effectively, and the lower part of the crankcase cover 6 is positioned downward. This can prevent it from bulging out. Therefore, the minimum ground clearance of the engine 3 can be increased, and there is no possibility that the engine 3 will become an obstacle when driving on rough roads or rough terrain.

Furthermore, the fact that the lower part of the crankcase 4 is substantially flat is advantageous in terms of the structure of the frame 1 because it does not interfere with the routing of the down tubes 2, 2, and the engine 3 can be easily mounted on the frame 1. There are advantages such as

It should be noted that the engine according to the present invention is not limited to a two-stroke engine, but can be implemented with a four-cycle engine, and the number of cylinders is not limited to a single cylinder, but may be a multi-cylinder engine.

Furthermore, although the above embodiments have been explained using a two-wheeled motor vehicle as an example, the same effect can be obtained even when the present invention is mounted on a four-wheeled vehicle such as a three-wheeled motor vehicle or a cart.

Further, in the above embodiment, the oil pump is provided at the front of the clutch, but it may be provided at the rear without any problem.

The present invention described in detail above has an oil pump and a clutch housing arranged side by side in the front-rear direction on one side of the crankcase, and a lower space located between the oil pump and the clutch housing. A water pump is arranged, and the water pump, clutch housing, and oil pump are arranged in a triangular positional relationship when viewed from one side of the crankcase. According to this, the water pump is located at the lowest part of the crankcase, so even if the engine cooling water in the pump is drained, this engine cooling water will not flow to other parts of the crankcase, such as the clutch housing. This prevents the crankcase from getting dirty. At the same time, the water pump is located between the clutch housing and the oil pump from below, making effective use of limited space and preventing the bottom of the crankcase from protruding downward. can. Therefore, excellent effects such as sufficient minimum ground clearance for the engine can be achieved.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being a side view and FIG. 2 being a sectional view of a water pump portion. 3...Engine, 4...Crankcase, 8...
...Oil pump, 11...Clutch housing,
12...Water pump.

Claims (1)

[Claims] 1. An oil pump and a clutch housing are arranged side by side along the longitudinal direction on one side of the crankcase, and a water pump is arranged in a lower space located between the oil pump and the clutch housing. A water-cooled engine characterized in that an oil pump, a clutch housing, and a water pump are arranged in a triangular positional relationship when viewed from one side of the crankcase.