JPS6221966B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Object of the Invention (1) Industrial Field of Application The present invention provides an engine, in particular, an engine, in particular, a rearwardly inclined cylinder block which is integrally connected to the upper part of the engine, particularly the crankcase, and which is connected to the upper part of the engine, particularly the crankcase. In an engine in which the rear part of the crankcase is extended to the rear, the breathing action inside the crankcase as the piston moves up and down can be smoothly performed without causing droplets of lubricating oil inside the case to be discharged to the outside. This invention relates to a breather device.

(2) Prior Art In the above-mentioned type of engine, an engine in which the oil separation chamber of the breather device is disposed within the crankcase is conventionally known (see Japanese Patent Laid-Open No. 121812/1983).

(3) Problems to be Solved by the Invention The above-mentioned conventional engine has a problem in that the effective capacity of the crankcase is reduced by the installation of the oil separation chamber. Also, in the above type of engine,
There is also the problem that a V-shaped dead space that is open to the rear is formed between the rear side wall of the rearwardly inclined cylinder block and the rear part of the upper wall of the crankcase that extends rearwardly.

An object of the present invention is to provide an engine breather device that can solve all of the above problems.

B. Structure of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention includes integrally connecting at least a rearwardly inclined cylinder block in the upper part of the crankcase, and In an engine in which the rear part of the crankcase extends rearward, the rear part of the upper wall of the crankcase and the upper part of the rear wall of the cylinder block are integrally connected via a connecting wall, and the upper wall, the rear wall, and the connecting An oil separation chamber having a substantially mountain-shaped cross section and communicating with the inside of the crankcase is formed between three parts of the wall, and a breather passage opening to the ceiling of the oil separation chamber is provided on the rear wall of the cylinder block. shall be.

(2) Effect According to the above configuration, the dead space between the rear side wall of the backward-inclined cylinder block and the rear part of the upper wall of the crankcase that extends rearwardly can be effectively used as the installation space for the oil separation chamber. used. Moreover, the above-mentioned connecting wall specially installed to form the oil separation chamber,
Since a truss structure can be formed in cooperation with the upper wall of the crankcase and the rear wall of the cylinder block, the rigidity of these walls can be increased.

(3) Embodiment An embodiment in which the present invention is applied to a V-type motorcycle engine will be described below with reference to the drawings.
In Figure 1, V mounted on the vehicle body frame F
The type engine E has a front cylinder block 2 that slopes toward the front of the vehicle body (to the right in FIG. 1) and a rear cylinder block 3 that slopes rearward in the upper part of the crankcase 1. Each cylinder block 2, 3 has a cylinder head 4.5 on the upper end surface.
are joined to each other, and the rear part of the crankcase 1 protrudes further rearward than the rear cylinder block 3.

As shown in Fig. 2, inside the crankcase 1,
Crank chamber 6 and transmission chamber 7 located behind it
and a clutch chamber 8 located on one side of the crank chamber 6 and the transmission chamber 7, and these chambers communicate with each other. The crank chamber 6 is provided with a common crankshaft 9 connected to the pistons in both cylinder blocks 2 and 3, and the transmission chamber 7 has input and output shafts 10 and 11, both of which are parallel to the crankshaft 9. A speed change gear mechanism 12 that interlocks the two shafts 10 and 11 is disposed, and the clutch chamber 8 has a starting clutch 13 attached to the input end of the input shaft 10, and the input member of the clutch 13 is connected to the crankshaft 9. A driving gear 14 and a driven gear 15 which are driven at a higher speed, and an oil pump driving sprocket 16 connected to the driven gear 15 are provided. 17 is a partition wall between the transmission chamber 7 and the clutch chamber 8, and 18 is a rear wheel drive sprocket fixed to the output end of the output shaft 11.

As shown in Figures 3 and 4, the crankcase 1
A connecting wall W is provided between the rear part of the upper wall 1a that covers the upper part of the transmission chamber 7 and the upper part of the rear wall 3a of the cylinder block 3.
As a result, an oil separation chamber 19 having a substantially mountain-shaped cross section is defined between the upper wall 1a, the rear wall 3a, and the connecting wall W. One end is adjacent to the clutch chamber 8 via the partition wall 17. Further, a plurality of through holes 20 are provided in the partition wall 17 to communicate the oil separation chamber 19 with the clutch chamber 8. Ceiling wall 19 of oil separation chamber 19
A breather passage 21 is bored in the center of the chamber 19 and opens in the opposite direction to the through hole 20. Furthermore, this breather passage 21 is connected to the rear cylinder block 3.
is bored through the wall 3a so as to pass through the rear wall 3a of the
It communicates with a breather pipe connecting pipe 22 protruding from the rear surface of the cylinder head 5. A breather pipe 23 connected to the atmosphere or a blow-by gas treatment device is connected to this connecting pipe 22, as is conventionally usual.

Therefore, when the inside of the crank chamber 6 is pressurized as the pistons in each cylinder block 2 and 3 descend,
The pressurized gas passes through the clutch chamber 8 and into the through hole 20.
The gas flows out into the oil separation chamber 19, where the flow rate is reduced to separate lubricant oil droplets contained in the gas, and then the gas changes direction and flows through the breather passage 21 to the breather pipe 23. In this way, excessive pressure rise within the crankcase 1 is prevented. The oil droplets separated in the oil separation chamber 19 accumulate appropriately at the bottom of the chamber 19, and then are naturally returned to the clutch chamber 8 through the lowermost through hole 20. In addition, a small hole is made in the bottom wall of the oil separation chamber 19, and the chamber 19
The oil accumulated in the transmission chamber 7 may be returned to the transmission chamber 7 through the small hole.

As shown in the illustrated example, the through hole 20 is connected to the deceleration driven gear 1.
5 and above the oil pump drive sprocket 16, these gears 1
In order to prevent the lubricating oil scattered from the sprocket 5 and the sprocket 16 from entering the through hole 20, it is desirable to adopt the following configuration.

That is, the partition wall 17 includes a lower partition wall 2 which is located below the through hole 20 and covers the upper part of the sprocket 16.
4, and a front partition wall 25 that stands up from the end of the partition wall 24 on the side where the sprocket 16 rotates and reaches the upper wall of the clutch chamber 8, and a side that is interposed between the through hole 20 and the gear 15. A partition plate 26 is fixed to the partition wall 17 with screws 27. Above partition wall 2
4, 25 and the partition plate 26 define an oil-proof chamber 28 that communicates with the through hole 20, and the opening 28 of this oil-proof chamber 28
A opens toward the direction of rotation of the sprocket 16. Therefore, the lubricating oil scattered from the gear 15 and the sprocket 16 is difficult to enter into the oil-proof chamber 28.

C. Effects of the Invention As described above, according to the present invention, at least the rearwardly inclined cylinder block 3 is integrally provided in the upper part of the crankcase 1, and the rear part of the crankcase 1 is arranged behind the cylinder block 3. In an extended engine, the rear part of the upper wall 1a of the crankcase 1 and the upper part of the rear wall 3 of the cylinder block 3 are integrally connected via a connecting wall W, and the upper wall 1a, the rear wall 3a, and the connecting wall are connected together. Between the three parties of W,
An oil separation chamber 19 having a substantially mountain-shaped cross section that communicates with the inside of the crankcase 1 is formed, and a breather passage 21 that opens to the ceiling of the oil separation chamber 19 is provided on the rear wall 3a of the cylinder block 3, so that the cylinder block 3 is tilted backward. The dead space between the rear wall 3a of the cylinder block 3 and the rear part of the upper wall 1a of the crankcase 1 that extends rearward can be effectively used as the installation space for the oil separation chamber 19. Upper, oil separation chamber 19
The effective capacity of the crankcase 1 is not reduced by the installation of the engine, and therefore, the overall size of the engine can be reduced. Further, since the connecting wall W specially provided to form the oil separation chamber 19 can form a sturdy truss structure in cooperation with the crankcase upper wall 1a and the cylinder block rear side wall 3a, these walls 1a, 3a Furthermore, the connecting wall W can be used both as a reinforcing wall and as an outer wall of the oil separation chamber 19 as described above, contributing to the simplification of the structure. Further, since the breather passage 21 opens at the top of the oil separation chamber 19 having a substantially mountain-shaped cross section, the opening and the oil separation chamber 19
This is advantageous in increasing the oil separation effect of the oil separation chamber 19 because the bottom portion can be separated as much as possible in the vertical direction.

[Brief explanation of the drawing]

Figure 1 shows a V for a motorcycle to which the device of the present invention is applied.
2 and 3 are cross-sectional views taken along the lines -- and -- of FIG. 1, and FIG. 4 is a cross-sectional view taken along the line -- of FIG. 3. E...Engine, W...Connection wall, 1...Crank case, 1a...Upper wall, 3...Rear cylinder block as a backward tilting cylinder block, 3a...Rear side wall, 19
...oil separation room, 19a...ceiling wall, 21...breather passage, 23...breather pipe.

Claims (1)

[Claims] 1 At least a rearwardly inclined cylinder block 3 is integrally installed in the upper part of the crankcase 1, and
In an engine in which the rear part of the crankcase 1 extends beyond the cylinder block 3, the rear part of the upper wall 1a of the crankcase 1 and the upper part of the rear side wall 3a of the cylinder block 3 are integrally connected via a connecting wall W. An oil separation chamber 19 having a substantially mountain-shaped cross section and communicating with the inside of the crankcase 1 is formed between the upper wall 1a, the rear wall 3a, and the connecting wall W. An engine breather device comprising an open breather passage 21 provided on the rear wall 3a of the cylinder block 3.