JPH0643457Y2 - Liquid cooling engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a liquid-cooled engine that cools the engine with water or oil.

[Conventional technology]

2. Description of the Related Art Conventionally, as a liquid cooling engine, there is one that cools the cylinder head and the cylinder block by forming a water jacket in the cylinder head and the cylinder block (see, for example, JP-A-63-183214).

[Problems to be solved by the device]

However, in the above-mentioned conventional technique, by cooling the cylinder head and the cylinder block, and by circulating the cooling liquid whose temperature has risen to the radiator, the temperature of the cooling liquid is lowered, so the cost can be reduced by installing the radiator. There are inconveniences such as rising, large volume and weight, and labor required for piping.

Therefore, a cover is joined to the outside of the crankcase to form a cooling liquid passage between the crankcase and the cover, and the heat of the cooling liquid is transferred to the outside by communicating with a cooling liquid passage having fins on the outer wall, for example. May be released. An example of this is shown in FIG.

FIG. 3 shows a part of a hard shaft type engine. In this figure, 1 is a crankshaft, and its axial direction S is set to the vertical direction. The crankshaft 1 has a journal portion 1a axially supported by a bearing portion 2b of a crankcase wall 2a of the crankcase 2 and penetrates the crankcase wall 2a. At the upper end of the crankshaft 1,
The flywheel 3 is fixed.

An annular oil groove 4 is engraved on the bearing 2b,
Lubricating oil is supplied to the bearing surface 2c between the crankshaft 1 and the bearing portion 2b. An oil seal 5 is attached to the bearing portion 2b above the journal portion 1a, so that the crankshaft 1
The lubricating oil is prevented from flowing out from the bearing surface 2c to the outside of the crank chamber 15.

A cover 6 is joined to the crankcase wall 2a with bolts (not shown), and the cover 6 forms a cooling liquid passage 7 between the cover 6 and the crankcase wall 2a. The cooling liquid in the cooling liquid passage 7 cools the crankcase 2 as well as the cylinder wall 8a formed integrally with the crankcase wall 2a. A gasket 9 is inserted in the joint surface 2d between the cover 6 and the crankcase wall 2a to seal the coolant passage 7.

The crankshaft 1 penetrates the cover 6. A charge coil 10 for ignition is fixed to the upper portion of the cover 6. An alternating voltage is generated in the charge coil 10 for ignition by rotating the permanent magnet 11 fixed to the flywheel 3.

By the way, in the above engine, since the cover 6 is provided on the outer side S1 of the oil seal 5, the cover 6 is positioned on the outer side S1 by that amount, and therefore the crankshaft 1
Becomes longer. For example, in this engine, the charge coil 10 for ignition fixed to the cover 6 and the engine accessories such as the flywheel 3 fixed to the crankshaft 1 project to the outside of the engine body, and the entire engine is in the axial direction S. To upsize.

Therefore, as shown in FIG. 4, the bearing portion 2b of the crankcase 2 is
Step 2e is formed in the vicinity of the cover 6 and the crankcase wall
Set the joint surface 2d of 2a to S2 inside the oil seal 5,
It can be considered to prevent the crankshaft 1 from becoming large in the axial direction S. However, in this case, because of the step portion 2e, the machining of the joint surface 2d of the crankcase 2 becomes complicated and the machining cost increases.

The present invention has been made in view of the above problems, and a sufficiently large coolant passage is formed outside the crankcase without increasing the size of the entire engine in the width direction and without increasing the processing cost. An object of the present invention is to provide a liquid-cooled engine that can be used.

[Means for Solving the Problems] In order to achieve the above-mentioned object, a liquid-cooled engine according to the present invention has a bearing portion of a crankcase wall which pierces a crankshaft of a crankcase and axially supports a journal portion thereof. The cover is brought into contact with and joined to form a coolant passage between the crankcase wall around the crankshaft and the cover, and the crankshaft is inserted into the through hole of the crankshaft in the cover from the bearing surface of the crankshaft to the crankshaft. An oil seal is provided to prevent the lubricating oil from flowing out of the chamber.

[Action]

According to this invention, the oil seal for preventing the outflow of the lubricating oil from the bearing surface of the crankshaft to the outside of the crank chamber is brought into contact with and joined to the bearing portion of the crankcase wall, not the bearing portion of the crankcase wall. By providing it in the through hole of the crankshaft in the cover, the axial length of the bearing portion of the crankcase wall is secured to be sufficiently large, and the supporting position of the crankshaft is maintained at a necessary and sufficient ten, while the position of the cover is maintained. The cooling liquid passage can be formed outside the crankcase without shortening the length of the crankshaft in the vicinity of the crank chamber, that is, the length of the entire engine in the crankshaft direction without increasing the size. Moreover, it is not necessary to form a step on the joint surface of the crankcase with the cover, and the joint surface of the crankcase is made flat, which facilitates machining of the joint surface, while suppressing an increase in machining cost. By forming a sufficiently large cooling liquid passage around the shaft, it is possible to exhibit a liquid cooling effect that is substantially the same as that in which a radiator is installed.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a cylinder 8 is integrally formed with the crankcase 2. The crankcase 2 pivotally supports the crankshaft 1 together with the oil pan 12.

Reference numeral 6A denotes a cover, which is brought into contact with the upper outer surface of the bearing portion 2b of the crankcase wall 2a and is positioned and joined by a knock pin or a wax seal (not shown). A cooling liquid passage 7 is formed between the cooling liquid passage 7 and the cooling liquid passage 7. The crankcase 2 has an outer wall 2f integrally formed into a double wall, and a coolant passage 7 is also formed between the double walls. The oil pan 12 and the cylinder head 13 also have outer walls 12a and 13a, respectively, and the coolant passage 7 is sealed by the crankcase 2, the oil pan 12, the cover 6A and the cylinder head 13. A large number of cooling fins 2g and 12b are integrally formed on the outer walls 2f and 12a, respectively.

The oil pan 12 is provided with an oil pump (not shown). The oil pump communicates with an oil supply passage 14 provided in the crankshaft 1, and supplies lubricating oil to the bearing surface 2c of the crankshaft 1 via the annular oil groove 4.

In FIG. 2, a cover 6A is formed with a through hole 6a through which the crankshaft 1 penetrates, and an oil seal 5 is fixed to the through hole 6a of the cover 6A. Therefore, the bearing portion 2b of the crankcase 2 is not provided with the oil seal 5, and the dimension of the bearing portion 2b in the axial direction S is shortened accordingly.

Reference numeral 21 denotes a first oil return path, which extends from below the oil seal 5 in the radial direction of the cover 6A and communicates with an oil return hole 22 formed in the gasket 9. A second oil return path 23 is formed in the crankcase wall 2a in the axial direction S and communicates with the oil return hole 22. Therefore, the lubricating oil on the bearing surface 2c of the crankshaft 1 returns to the crank chamber 15 via the oil return paths 21 and 23 and the oil return hole 22.

In FIG. 1, 24 is a cooling air intake, and 25 is a cooling fan integrally formed with the flywheel 3. 26 is a baffle plate, which is provided so as to cover the entire engine and has a cooling fan.
25, the cooling air C introduced from the cooling air intake 24,
It guides to the cooling fins 13b of the cylinder head 13 and the cooling fins 2g and 12b of the crankcase 2 and the oil pan 12. As a result, the cooling liquid in the cooling liquid passage 7 is cooled and the engine is cooled. The cooling liquid passages 7 and the cooling liquid passages in the cylinder head communicate with each other.

As the cooling liquid, in addition to using water or oil, a method of circulating the lubricating oil circulating inside the crankcase as it is in the cooling system is also used. Therefore, the gasket 9 has a sealing property with respect to the lubricating oil and the cooling liquid, and for example, a sheet material mixed with asbestos or rubber can be used. Although not shown, a well-known pump and a thermostat are provided in the cooling liquid passage 7, and the cooling liquid circulates according to the temperature of the cooling liquid. Further, 27 is an igniter, which is fixed to the cover 6A.

Other configurations are the same as those in the example of FIG. 3, and the same portions or corresponding portions are denoted by the same reference numerals and detailed description thereof will be omitted.

In the above structure, the oil seal 5 is provided in the through hole 6a of the cover 6A shown in FIG.
The bearing strength of the crankshaft 1 is increased by ensuring a sufficiently long axial direction S of the bearing portion 2b of 2a, and in order to obtain the necessary and sufficient support strength of the crankshaft 1, the bearing portion 2b has an axial direction S of S. The length is small. Therefore, the position of the cover 6A approaches the crank chamber 15, and accordingly, the length of the crankshaft 1 penetrating the bearing portion 2b and the cover 6A is shortened, and the flywheel 3 fixed to the crankshaft 1 is shortened. Alternatively, the engine accessories such as the charge coil 10 and the igniter 27 fixed to the cover 6A in FIG.
It is possible to suppress overhang to the outside S1 of the engine body. As a result, the engine does not increase in size in the axial direction S of the crankshaft 1.

On the other hand, the joining surface 2d between the crankcase wall 2a and the cover 6A shown in FIG. 2 does not need to have the stepped portion 2e as shown in FIG. 4, so that the joining surface 2d can be easily machined. Therefore, there is no possibility of causing an increase in processing cost.

By the way, when the step 2e is formed as shown in FIG.
Since the step 2e projects from the crankcase 2, the crankcase 2 and the partition plates such as the corrugated cardboard cannot be stacked alternately, which makes it difficult to store and transport the crankcase 2. On the other hand, according to this invention, since the joint surface 2d of the crankcase 2 shown in FIG. 2 has a flat shape, the crankcase 2 and the partition plate can be easily stacked up and down. Easy to carry.

By the way, a cooling liquid passage 7 is formed between the crankcase wall 2a and the cover 6A.
Since it is connected to a cooling liquid passage (not shown) in the cylinder head 13 in the figure, there is an advantage that the temperature distribution of the engine main body is likely to be uniform and distortion is unlikely to occur.

Further, in the above embodiment, the cooling fins 2g and 12b are integrally formed with the crankcase 2 and the oil pan 12, respectively, while the cooling air C is applied to the cooling fins 2g and 12b.
Is being guided. Therefore, the cooling liquid in the cooling liquid passage 7 is not limited to the cooling fin 13b of the cylinder head 13,
It is cooled by the cooling air C through the cooling fins 2g and 12b. As a result, the cooling liquid can be sufficiently cooled, and a radiator is not needed.

[Effect of device]

As described above, according to the present invention, the oil seal for preventing the outflow of the lubricating oil from the bearing surface of the crankshaft to the outside of the crankcase is provided not on the bearing portion on the crankcase wall but on the bearing portion on the crankcase wall. By providing it in the through hole of the crankshaft in the cover that abuts and joins to form a cooling liquid passage with the crankcase wall, a sufficiently large axial length of the bearing portion of the crankcase wall is secured. While maintaining the necessary and sufficient crankshaft support strength,
By making the position of the cover closer to the crank chamber and shortening the length of the crankshaft, it is possible to form the coolant passage outside the crankcase while making the entire engine as small as possible. In addition, it is not necessary to form a step on the joint surface of the crankcase with the cover, and the joint surface of the crankcase is made flat to facilitate machining of this joint surface, while suppressing an increase in processing cost It is possible to form a sufficiently large cooling liquid passage around the axis,
Therefore, compared with the radiator installed, the cooling effect is almost the same as that of the radiator installed without incurring increase in equipment cost, weight, and assembly cost due to increase in man-hours. You can

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical cross-sectional view of a liquid-cooled engine showing an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of the same part, and FIG. 3 is a liquid not included in the present invention. A cross-sectional view of a main part showing an example of a cold engine,
FIG. 4 is a sectional view of an essential part showing another example of the same. 1 ... Crank shaft, 2 ... Crank case, 2a ... Crank case wall, 2c ... Bearing surface, 2d ... Joining surface, 5 ... Oil seal, 6A ... Cover, 6a ... Through hole, 7 ... … Coolant passage, 9 …… Gasket, 15 …… Crank chamber.

Claims (1)

[Scope of utility model registration request] 1. A crankcase wall, which penetrates a crankshaft in a crankcase and axially supports a journal portion thereof, penetrates the crankshaft, and is abutted and joined to a bearing portion of the crankcase wall. A cover that forms a cooling liquid passage between the crankcase wall and the crankcase wall, a gasket that is inserted in a joint surface between the cover and the crankcase wall to seal the cooling liquid passage, and the cover In the through hole of the crankshaft, an oil seal for preventing the lubricating oil from flowing out from the bearing surface of the crankshaft to the outside of the crank chamber.