JPS597735A - V-type engine - Google Patents

Abstract

PURPOSE:To make compact a V-type engine provided with a clutch at one end of the main shaft of a transmission gear, by arranging a reduction pinion between the shaft end bearing of a crank shaft and a crank web most adjacent to the bearing. CONSTITUTION:Rotation of a crank shaft 40 is transmitted through a reduction pinion 90 and a reduction gear 88 to a clutch housing 86, thereby driving rear wheels by way of a transmission gear 46, a sprocket 94 and a chain 98. As the pinion 90 is fixed between an end journal 52c of the crank shaft 40 and a crank web 50d most adjacent to the journal 52c, a clutch 84 may be arranged on the central side of an engine 10, and an amount of projection of the clutch 84 may be reduced. Thus, the engine may be made compact, and a bank inclined to the transmission gear side may be enhanced, thereby enabling the engine to be made more compact.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a V-type engine in which a transmission is disposed within a crankcase and a clutch is provided at one end of a main shaft of the transmission.

BACKGROUND ART In engines used in motorcycles and the like, a transmission is disposed within the crankcase to reduce the size of the engine unit. A clutch is disposed at one end of the main shaft of the transmission, and this clutch has a large diameter. Particularly in ■-type engines where one bank (for example, a cylinder) is tilted toward the transmission side, interference between this bank and the clutch becomes a problem.

For example, there is a type engine that is equipped with a horizontal crankshaft, a transmission is disposed behind the crankshaft, and each bank is tilted forward and backward. In this case, in order to avoid interference with the clutch of the main shaft of the transmission when the bank tilts backward, conventionally, the reduction gear that transmits the rotation of the crankshaft to the clutch housing is protruded from the bearing at one end of the crankshaft. The clutch was placed in such a way that it protruded to the side of the engine. This has caused a problem in that the overall width of the engine increases.

On the other hand, the crankshaft is IiM If! In order to reduce the engine width, some in-line multi-cylinder engines, such as those with a t-speed, have a gear formed on the outermost crank web of the crankshaft, and the white part of this crank web is used as a small reduction gear. In other words, in an in-line multi-cylinder engine, the cylinder block can be sufficiently tilted forward, making it possible to avoid interference between the cylinders and the clutch without reducing the amount by which the clutch protrudes to the side of the engine.

However, in the case of the above-mentioned (2) type engine where the bank on the - side is inclined toward the transmission side, there is a problem that if the crank web is made into an IT speed small gear, the clutch and bank will interfere.

The present invention has been made in view of the above circumstances, and has the following objects: (1) to provide a V-type engine that reduces the amount of clutch protrusion in the direction of the crankshaft and is suitable for downsizing the engine as a whole; be.

In order to achieve this object, the present invention includes a transmission disposed in a crankcase, a clutch disposed at one end of the main shaft of the transmission, and a reduction gear mounted on the crankshaft and the clutch. and a reduction gear provided in the housing of the crank.

In a V-type engine that transmits shaft rotation to a clutch, the reduction gear is disposed between a bearing at the end of the crankshaft and a crank web closest to the bearing. The present invention will be described in detail below based on the illustrated examples.A)
3.

Fig. 1 is a side view of a motorcycle to which an embodiment of the present invention is applied, Fig. 2 is a side view of its engine, and Fig. 3 is its Il.
1 is a cross-sectional view taken near ->1 to the l-1iI line.

In Fig. 1, numeral 10 at 4.5 is a water-cooled, overhead camshaft type engine. This engine 10 has a down tube 12 at the front and a main tube 14 at the rear.
They are fixed to the 1st and 1st ends of each. main tube 1
4 and one end of the down tube 12 is fixed to a steering head pipe 16, and a front fork 18 is attached to this head pipe 16. 20 is a front wheel attached to this front fork 18, and 22 is a handle bar. 24 is a fuel tank attached to the main pipe 14 behind the head pipe 16, 26 is a driver's seat behind it, and 28 is a rear wheel.

A radiator 30 is attached to the down tube 12 and cools the cooling water circulating inside the engine 10.

Next, engine IO will be explained based on FIG. 2.3. This engine 10 includes a front bank 32 that tilts forward and a rear bank 34 that tilts backward. The crankcase 36 is divided into two parts, and is formed by a -L case 36A and a lower case 36B. Between the split surfaces of the upper and lower cases 36A136B, a balance weight 38, a crankshaft 40, a main shaft 42, and a subshaft 44 are rotatably held in order from the front. The balance weight 38 rotates at the same speed in the opposite direction to the crankshaft 40, and has the function of mainly absorbing the primary vibration of the crankshaft 40. A large number of transmission gear groups are provided on the main shaft 42 and the counter shaft 44, and a known constant-mesh type transmission 46 is formed by these gears. That is, the transmission 46 is disposed within the crankcase 36.

This engine 10 includes four cylinders. The crankshaft 40 has crank pins 48a and 48 with a phase difference of 180 degrees.
b, four crank webs 5a to 50d, and three journal parts 52 (52a% 52b, 52c). Each crank pin 48 has a piston 5 of the rear bank 34.
4 (54a.

54b) is connected to the connector 56 (56as56b).
) are attached to the left side, and connecting rods 60 (60a, 60b) connecting the pistons 58 (only one shown) of the front bank 32 are attached to the right side.

As a result, the front bank 32 is displaced to the right with respect to the center line of the engine 1o, and the left bank 34 is displaced to the left.

The crankshaft 40 is the upper and lower case 7, 36A.

Between 36B, plain bearing 51 (51a, 51b% 51C
) is held at three journal portions 52 via the journal portions 52. A known flywheel magnetron 2 is attached to the left protruding end of the crankshaft 40, and a sprocket 64 is formed at the right protruding end.

66 is an intermediate shaft disposed within the angle of each bank 32,34. This intermediate shaft 66 is equipped with a sprocket 68,
It is rotated by the crankshaft 40 (through a 70ft chain wound between the crankshaft 40 and the sprocket 64). Each bank 32.34 has two overhead cams 72 (72a).

72b), 74 (74a, 74b). It is driven by an intermediate shaft 66 via a camshaft 72Ai of the front bank 32 and a cam chain 76 disposed on the side opposite to the deflection direction (right side) of the front bank 32.

The camshaft 74 of the rear bank 34 is driven by the intermediate shaft 66 via a cam chain 78 disposed on the opposite side to the deflection direction (left side) of the rear bank 34 .

Camshaft 72.74 is connected via chain 70.76.78,
The known intake valve 8 rotates at half the speed of the crankshaft 40.
0. Open and close the exhaust valve 82 (only one is shown in Figure 2).

84 is a wet multi-plate clutch, which is attached to the right end of the main shaft 42 of the transmission 46. A large reduction gear 88 is fixed to the housing 86 of the clutch 84. On the other hand, the crankshaft 40 includes a flat bearing 51c that holds the journal portion 52c on the clutch 84 side, and a flat bearing 51c that holds the journal portion 52c on the clutch 84 side.
A reduction pinion gear 90 is fixed so as to be located between the crank web 50d closest to the crank web 50d. This gear 90 meshes with the large reduction gear 88 . In FIG. 3, a gear 92 fixed to the crankshaft 40 at a position substantially symmetrical to the reduction gear 00 drives the balance weight 38 (FIG. 2).

A sprocket 94 is fixed to the left end of the subshaft 44,
A drive chain 98 is wound around this sprocket 94 and the sprocket 96 of the rear wheel 28.

Next, the operation of this embodiment will be explained. As the crankshaft 40 rotates, the intermediate shaft 66 and camshafts 72, 74 rotate at predetermined timing, and the intake/exhaust valves 80, 82 open and close. Further, the rotation of the crankshaft 40 is transmitted to the clutch housing 86 via the reduction gear/large gear 90.88, and is transmitted to the rear wheel 28 via the transmission 46, sprocket 94, and chain 98.

Since the reduction pinion gear 90 is fixed between the journal part 52c at one end of the crankshaft 40 and the crank web 50d closest thereto, the reduction gear pinion 90 is fixed between the journal part 52c at one end of the crankshaft 40 and the crank web 50d that is closest to this. Compared to a conventional engine, the clutch 84 can be placed closer to the center of the engine 10, and the amount of protrusion of the clutch 84 can be reduced. In addition, when this reduction gear is provided on the crank web 50d,
In order to prevent interference between the rear bank 34 and the clutch 84, it is difficult to increase the backward tilt angle of the rear bank 34. However, according to this embodiment, such inconvenience is minimized and the rear bank 3
4 can be strongly tilted backwards, and it is possible to promote downsizing of the engine 10.

As described above, the present invention arranges the reduction gear between the bearing at the end of the crankshaft and the crank web closest to this bearing, so it is possible to reduce the amount of clutch protrusion and downsize the engine. can.

Also, compared to installing a reduction gear on the crank web,
Since it becomes possible to strengthen the slope of the bank that slopes toward the transmission side, the engine can be further downsized.

[Brief explanation of drawings]

FIG. 1 is a side view of a motorcycle using an embodiment of the present invention, FIG. 2 is a side view of the engine, and FIG. 3 is a cross-sectional view of the motorcycle in the vicinity of line 1--2. 10...Engine, 36...Crankcase,
42... Main shaft, 46... Transmission, 50... Crank web, 51... Plain bearing, 84... Clutch, 86... Clutch housing, 88... Reduction large gear, 90...・,9 reduction pinion gear. Patent applicant Yamaha Motor Co., Ltd. Agent Patent attorney Yama 1]] Fumio (10)

Claims (1)

[Claims] It is equipped with a transmission disposed in the crankcase, a clutch disposed at one end of the main shaft of the transmission, and a small reduction gear provided on the crankshaft and a large reduction gear provided on the housing of the clutch. , in the V-type engine that transmits the rotation of the crankshaft to the clutch, the reduction gear is disposed between a bearing at the end of the crankshaft and a crank web closest to the bearing. engine.