JPH0235124B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention has two first and second cylinders arranged one behind the other, and the first and second cylinders are mutually inclined in a V-shape. This invention relates to an overhead valve camshaft type V-type engine for two-wheeled vehicles.

[Prior Art] Conventionally, in this type of V-type multi-cylinder engine,
Some engines have a camshaft provided above each cylinder to drive the intake valve and exhaust valve, and this camshaft is linked to the crankshaft via a drive system.

In this case, the crankcase is divided into upper and lower halves at the position where the crankshaft is arranged, and the two first cylinders and the second cylinder are formed integrally with each other in a V-shaped incline with respect to the upper part. ing.

[Problem to be solved by the invention] However, in the conventional technology as mentioned above, the first
The cylinder blocks of the cylinders and the second cylinder are asymmetrically formed in the cylinder arrangement and the case part that houses the drive system, so the heat generated in the first and second cylinders is transferred to the upper part of the crankcase. The heat was not transmitted evenly, creating a temperature imbalance in the upper member, which caused various problems such as gas leakage at the mating surface of the cylinder head and cylinder block due to thermal deformation.

The present invention has been made in view of the above-mentioned problems of the conventional technology, and its purpose is to distribute heat from the first and second cylinders evenly to the upper member of the crankcase. It is an object of the present invention to provide a V-type engine in which a rear wheel power take-off mechanism can be easily installed, while preventing thermal deformation of the upper crankcase member.

[Means for solving the problem] In order to achieve the above object, V in the present invention
The 2-type engine has overhead cam shafts 8, 9, 10, and 11 at the top that open and close intake and exhaust valves 4, 5, 6, and 7.
A V-type multi-cylinder engine A in which two first cylinders a, a' and two second cylinders b, b' are arranged in front and behind each other, and these first cylinders a, a' and second cylinders b, b' are inclined relative to each other. , the crankcase 1 is attached to the upper and lower two members 1a, 1
b, its upper member 1a and the cylinder blocks of the first cylinders a, a' and the second cylinders b, b'.
a ₁ and b ₁ are integrally formed, and the respective center lines l ₁ and l ₁ ' of both first cylinders a and a' are aligned with center lines l ₂ and l ₂ ' of both second cylinders b and b'. On the other hand, the center lines l ₁ and l ₁ ′ sides, which are on the same side in the axial direction of the crankshaft 3, are deviated so as to be located closer to the rear wheel power take-off 48 than the center lines l ₂ and l ₂ ′ sides, and both first cylinders a, a' and second cylinder b,
The cylinders a, a′,
The first drive system c or c' that connects the camshafts 8, 9, 10, 11 of b and b' to the crankshaft 3 is accommodated.
A case 28 and a second case 29 are provided, and this first case 28 and a second case 29 are provided.
The case and the second case are arranged offset from each other in the direction of the crankshaft, and are formed integrally with the respective cylinder blocks, so that the cylinder heads a ₂ and b ₂ of the first cylinder and the second cylinder are symmetrical. , is something.

[Operation] According to the above means, both the first cylinders a, a' and the second cylinder
The external shapes of cylinder blocks a ₁ , b ₁ and cylinder heads a ₂ , a ₂ are symmetrical with cylinders b and b', and the heat generated from these first and second cylinders is transferred to the upper part of the crankcase. Evenly transmitted.

Also, both the front first cylinders a and a' are connected to the rear two second cylinders.
Since it is deviated to be located closer to the rear wheel power take-off 48 than the cylinders b and b', the installation of gears, clutches, etc. used for rear wheel power take-off will be particularly affected by the two rear second cylinders. It can be done easily.

[Embodiment] An example of carrying out the present invention will be described with reference to the drawings. In the drawing, A is a V-type engine, 1 is a crankcase, 2 is a crankcase cover, and 3 is a crankshaft.

The engine A has two first cylinders a and
a' and second cylinders b, b', and these two first cylinders
The cylinders a, a' and the second cylinders b, b' are inclined in a V-shape around the crankshaft 3 and are arranged to face each other.

Each of the cylinders a, a' and b, b' is composed of a cylinder block a ₁ , b ₁ of the same body, and a cylinder head a ₂ , a ₂ connected to the upper part, that is, the cylinder block a ₁ , b _{1 .} are provided with intake valves 4, 5 and exhaust valves 6, 7, respectively.

8, 9 and 10, 11 are the intake and exhaust valves 4, 5,
It is a camshaft that drives valves 6 and 7, and each valve 4, 5,
6, 7, each cylinder a, b
It is held between the upper ends of the cylinder heads a ₂ and a ₂ and the covers 12 and 13 attached thereto.

On the other hand, the crank case 1 is approximately the crankshaft 3.
It _is divided into two upper and lower members 1a and 1b from a mating surface 1c set according to the level _of
It is composed of the same body.

As shown in FIGS. 2 and 4, the center lines l ₁ , l ₁ ' of both first cylinders a, a' are aligned with the center lines l 2 , _{l 2} ' of both second cylinders b, b'. , the center line l ₁ , l ₁ ' side which is the same side as the axial direction of the crankshaft 3 is the center line l ₂ ,
It is arranged offset so that it is located closer to the rear wheel power take-off 48 than the _l2 side.

In the V-type engine A, the camshaft 8,
A drive system c for driving the camshafts 8, 9, 11 is provided, and this drive system c is arranged in a space d formed between the opposing cylinders a and b.
0 and 11 are connected to the crankshaft 3 and driven.

Reference numeral 14 denotes a housing part provided in the space d to house the drive system c, and is the same as the cylinder blocks a ₁ , b 1 of each cylinder a, a', b, b _' and the upper member 1a of the crankcase 1. The intermediate shaft 15, which is integrally constructed and constitutes a drive system c, is housed therein.

The intermediate shaft 15 includes the crankshaft 3 and the camshaft 8,
9, 10, and 11, and transmits the rotation of the crankshaft 3 to the camshafts 8, 9, 10, and 11. It is arranged approximately directly above and parallel to the crankshaft 3, and its both ends are connected to the housing portions. It is supported by bearings on the left and right side walls of 14 and protrudes outward from the housing portion 14 .

16 is a sprocket provided at one end of the intermediate shaft 15, that is, the left end in FIG.
It is connected to a sprocket 17 provided on the crankshaft 3 via a chain 18.

The sprocket 17 on the side of the crankshaft 3 is provided at the end of the crankshaft 3 protruding outward from the crankcase 1, and has half the number of teeth of the sprocket 16 of the intermediate shaft 15.

Therefore, the rotation of the crankshaft 3 is reduced to 1/2 and transmitted to the intermediate shaft 15, and the intermediate shaft 15 rotates.

A cover 19 covers the sprockets 16, 17 and the chain 18, and is formed integrally with the crankcase cover 2.

20 and 21 are sprockets provided in the middle part of the intermediate shaft 15 in the housing part 14;
The camshafts 8, 9 and 10, 11 are connected to sprockets 22, 23 and 24, 25 provided at intermediate portions thereof via chains 26, 27, respectively.

The sprockets 20, 21 and 22, 23,
24 and 25 each have the same number of teeth.

Therefore, the camshafts 8, 9, 10, 11 are connected to the intermediate shaft 1.
It rotates at the same speed as 5.

Further, the chains 26 and 27 are connected to a passage 28' in a first case 28 and a second case 29, which are formed on the opposing surfaces of the housing portion ₁₄ and the cylinder heads a 2 and b ₂ .
29' into the cylinder heads a ₂ and b ₂ of the front and rear cylinders a and b, but the passage 2
8' and 29' are the cylinders a and 29', respectively, as shown in FIG.
a′, b, b′, and bores a ₃ , a ₃ ′ and
It is located away from b ₃ and b ₃ ′ so as not to interfere with them.

Thus, the cylinder heads a 2 , b ₂ of the first cylinders a, a' and the second cylinders b, b _' become completely symmetrical and can be cast using the same mold, This makes it possible to significantly reduce manufacturing costs.

Furthermore, the bores a ₃ , a ₃ ′ and b ₃ of each cylinder a, b,
b ₃ ′ can be made as close as possible to each other, and the width of the left and right sides of the engine A can be narrowed to make the engine A smaller.

Reference numerals 30 and 31 are covers that are connected to the passages 28' and 29' and are provided to cover the chains 26 and 27, and are made of the same body as the cylinder heads a ₂ and b ₂ of the cylinders a and b. 14 It is fixed to the outer wall with bolts etc.

Thus, when the V-type engine A is started, the crankshaft 3 rotates, and the rotation is reduced to 1/2 and transmitted to the intermediate shaft 15.

As the intermediate shaft 15 rotates, the camshaft 8,
9, 10, and 11 rotate at the same speed, and the intake and exhaust valves 4, 5, 6, and 7 are driven.

Also, during engine operation, the heat generated from the first and second cylinders a, a' and b, b' is transferred from the cylinder heads a ₂ and b ₂ , which are completely symmetrical, to the cylinder blocks a ₁ , b ₁ through upper member 1a
is transmitted evenly. Therefore, the upper member 1a
Since the temperature balance can be maintained, thermal deformation is reduced.

Incidentally, since the intermediate shaft 15 is rotated in conjunction with the crankshaft 3, it is conceivable that this may also be used as a drive shaft for auxiliary equipment.

In this embodiment, a water pump 32 for circulating cooling water for cooling the engine A is provided at the end of the intermediate shaft 15 opposite to the sprocket 16, and the end on the sprocket 16 side is further extended outward. A generator 33 is provided there.

Since the generator 33 is provided at the end of the intermediate shaft 15, the generator 33 is placed above the engine A and protrudes to the side, making it easier to be hit by the wind while driving and generate electricity. The cooling performance of the machine 33 can be improved.

Furthermore, by arranging the generator 33 at a position away from the change pedal 34, there is an effect that the generator 33 does not interfere with the operation of the change pedal 34 as in the conventional case, and the generator 33 is placed in a position away from the engine A. Even if it protrudes to the side, it is engine A.
Since it is located at the top, the bank angle will not become small when the motorcycle is running.

Next, FIG. 5 shows a modification in which the intermediate shaft 15 is also used as a drive shaft for auxiliary equipment as described above.

In the engine shown in FIG. 5, an ignition pickup device 35 is provided at the end of the intermediate shaft 15 on the sprocket 16 side in place of the generator 33.

In this case, the generator 33 is provided at the end of the crankshaft 3 as in the conventional case.

Therefore, the advantage of providing the ignition pickup device 35 at the end of the intermediate shaft 15 is that the intermediate shaft 15 rotates at the same speed as the camshafts 8, 9, 10, 11, so that the intake and exhaust valves 4, It is possible to reliably synchronize the operation of the device 35 with the operations of elements 5, 6, and 7, and the ignition timing can be accurately controlled.

Next, FIG. 6 shows a modification of the drive system.

In the drive system c' shown in FIG. 6, power is transmitted from the crankshaft 3 to the intermediate shaft 15, and from the intermediate shaft 15 to the camshafts 8, 9, 10, 11 through gear trains. It is becoming more and more popular.

That is, gears 36 and 37 are provided at the ends of the crankshaft 3 and the intermediate shaft 15, respectively.
7 are connected via a gear 38 in the middle.

The camshafts 8, 9 and 10, 11 are connected to each other via gears 39, 40 and 41, 42 provided thereon, and gears provided on the camshafts 9, 10 on the side closer to the intermediate shaft 15. 40,41
However, a gear 43 provided at the intermediate portion of the intermediate shaft 15 and two gears 44, 45 and 46, 4 respectively between them.
It is connected via 7.

The gears 36, 37, 38 from the crankshaft 3 to the intermediate shaft 15 are housed inside the cover 19 which accommodates the sprockets 16, 17 and the chain 18 in the embodiment, Gears 43, 4 to shafts 9, 10
4, 45, 46, and 47 are the storage section 14 and the passage 2 that accommodated the chains 26 and 27 in the above embodiment.
8', 29' and the covers 30, 31.

[Effects of the Invention] Since the present invention is configured as described above, the cylinder heads of both first cylinders a, a' and both second cylinders b, b'
a ₂ and b ₂ can be made symmetrical, so that the heat generated from the first and second cylinders during operation is evenly transmitted to the upper part of the crankcase, so that the temperature of the upper part is reduced. Balance is maintained and thermal deformation is reduced. Therefore, there are problems such as gas leakage at the interface between the cylinder head and the cylinder block, damage to the cylinder block, and noise caused by changes in the meshing clearance of the gears when the drive system uses gears for power transmission. etc. can also be prevented.

In addition, since the cylinder heads of the first and second cylinders can be made completely symmetrical, it is possible to cast the cylinder heads of both cylinders using the same mold, which significantly reduces manufacturing costs. can be reduced.

Furthermore, since the two front first cylinders are positioned closer to the rear wheel power extraction side than the rear two second cylinders, gears, clutches, etc. used for rear wheel power extraction can be installed in the rear two cylinders. You can do it freely without being particularly affected by the two-cylinder engine.

[Brief explanation of drawings]

FIG. 1 is a side view showing a V-type engine according to the present invention, FIG. 2 is a cutaway plan view of the same, FIG. 3 is an enlarged sectional view taken along the - line in FIG. 1, and FIG. 5 is a longitudinal sectional view showing a modification in which the intermediate shaft of the drive system is also used as a drive shaft for auxiliary equipment, and FIG. 6 is a partial view showing a modification of the drive system. It is a notch side view. A...engine, a, a'...first cylinder, b,
b'...Second cylinder, _a1 , _b1 ...Cylinder block,
a ₂ , b ₂ ... cylinder head, c, c' ... drive system,
l ₁ , l ₁ ′...center line of both first cylinders, l ₂ , l ₂ '... center line of both second cylinders, 1... crankcase, 1a...
...Upper member of crankcase, 1b...Lower member of crankcase, 3...Crankshaft, 4, 5,
6, 7... Intake and exhaust valve, 8, 9, 10, 11... Overhead cam shaft, 28... First case, 29
...Second case, 48...Rear wheel power extraction.

Claims (1)

[Claims] 1 The two first cylinders a, a' and the second cylinders b, b' each have overhead camshafts 8, 9, 10, 11 at the top that open and close the intake and exhaust valves 4, 5, 6, 7, respectively. A V-type multi-cylinder engine A in which the first cylinders a, a′ and the second cylinders b, b′ are inclined relative to each other.
, the crankcase 1 is attached to the upper and lower two members 1a,
1b, its upper member 1a and the cylinder blocks of the first cylinders a, a' and the second cylinders b, b'.
a ₁ and b ₁ are integrally formed, and the respective center lines l ₁ and l ₁ ' of both first cylinders a and a' are aligned with center lines l ₂ and l ₂ ' of both second cylinders b and b'. On the other hand, the center lines l ₁ and l ₁ ′ sides, which are on the same side in the axial direction of the crankshaft 3, are deviated so as to be located closer to the rear wheel power take-off 48 than the center lines l ₂ and l ₂ ′ sides, and both first cylinders a, a' and second cylinder b,
The cylinders a, a′,
The first drive system c or c' that connects the camshafts 8, 9, 10, 11 of b and b' to the crankshaft 3 is accommodated.
A case 28 and a second case 29 are provided, and this first case 28 and a second case 29 are provided.
The case and the second case are arranged offset from each other in the direction of the crankshaft, and are formed integrally with the respective cylinder blocks, so that the cylinder heads a ₂ and b ₂ of the first cylinder and the second cylinder are symmetrical. This is an overhead valve camshaft V-type engine for motorcycles, which is characterized by: