JPH0336716B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motorcycle equipped with a horizontally opposed engine having front and rear cylinders, a front cylinder extending forward and a rear cylinder extending rearward across a crank chamber. The reason for this is to prevent the distance between the front and rear axles, that is, the wheelbase, from becoming too large when a horizontally opposed engine with a large cylinder axis is installed in a vehicle with its axis facing in the longitudinal direction. be.

It is generally known that horizontally opposed engines are well-balanced and can be operated quietly. However, on the other hand, since the length of the cylinder axis is large, when mounting this on a motorcycle, if the cylinder axis direction is oriented in the left-right direction, the vehicle body width will increase and it will be difficult to obtain a large bank angle. In the front-rear direction, unless the wheelbase is made larger, problems such as interference between the rear arm that supports the rear wheel and the rear cylinder tend to occur.

In order to eliminate such problems, this invention is characterized by arranging the axis of the cylinder in the front-rear direction and positioning the axis above the support shaft of the rear arm to reduce interference between the rear arm and the cylinder. .

The present invention will be explained below with reference to illustrated embodiments. In the motorcycle of the embodiment, a front wheel 4 is supported via a front fork 3 to a steering shaft tube 2 located at the front end of a vehicle body frame 1 assembled by welding steel pipes so as to be able to turn left and right. The vehicle body frame 1 has a main column 5 extending rearward from the steering shaft tube 2 and a down tube 6 extending downward,
The former 5 supports the rear part of the engine 7, and the latter 6 supports the front part. Reference numerals 8 and 9 indicate brackets for fixing the engine 7 to the vehicle body frame with bolts.

A bracket 10 provided at the lower end of the main column 5 has a base end of a rear arm 12 supporting a rear wheel 11 rotatably supported by a support shaft 13. At the rear of the vehicle body frame 1 is a seat support frame 1 that extends further rearward.
4 and its reinforcing frame 15 are assembled by welding,
A buffer spring 16 for the rear wheel 11 is attached between the seat support frame 14 and the rear arm 12. 1
7 is a fuel tank installed on the upper surface of the vehicle body frame 1;
8 is a passenger seat.

The engine 7 is a horizontally opposed water-cooled engine having a front cylinder 22 extending forward from a central crank chamber 21 and a rear cylinder 23 extending rearward. It is arranged so that it runs horizontally. Further, carburetors 24, 24 are provided on the upper surface of each cylinder, and these communicate with a common air cleaner 25. 25a is an air intake pipe, and 25b is a paper type over member. An exhaust pipe 26 extends downward from the front cylinder 22 and opens into the atmosphere via a first muffler 27 and a second muffler 28. Note that the exhaust pipe 29 of the rear cylinder 23 is connected to the support shaft 13.
The first muffler 27 extends downward in front of the muffler 27 and is directly connected to the first muffler 27 .

More specifically, as shown in FIGS. 2 to 7, the engine 7 has a crankshaft 31 disposed left and right with respect to the direction of travel, which is sandwiched between a front case 32 and a rear case 33 that constitute a crank chamber 21. There is. Each case 32, 33 is formed as a cylinder block having two cylinder holes 34, 34, respectively. 35 is a cylinder head, and 36 is its cover. A timing shaft 37 is further supported on the joint surface between the front case 32 and the rear case 33.
As shown in FIG. 5, the crankshaft 31 is driven by a chain 38, and in the drive chamber 21a formed between the crankshaft 31 and the cover 32a that covers the left outer surface of the crank chamber 21, another chain 39 is used to drive the intake air. Two camshafts 41, one for exhaust and one for exhaust, are driven. 42 is an electric machine shaft connected to the starter motor 43 and the generator 44, and 45 is a one-way clutch that transmits the rotation of the electric motor 43 to the electric machine shaft 42.

A transmission chamber 46 is located below the crank chamber 21, and an input shaft 47 and an output shaft 48 of the transmission are supported by the rear case 33. Crank chamber 21
A clutch chamber 21b is formed between the right outer surface of the clutch chamber 21b and a cover 33a covering the clutch chamber 21b, and a clutch 49 is provided on an input shaft 47 protruding into the clutch chamber 21b. 50 is a lubricating oil tank. The clutch 49 has a pinion 52 fixed to the crankshaft 31.
A reduction gear 53 connected to a clutch 49
While being decelerated and driven by a gear train consisting of
It is adapted to drive the input shaft 47. The output shaft 48 of the transmission drives the rear wheels 11 via a chain 54 as is well known. In FIG. 3, a hole 55 provided in the wall of each cylinder is used to engage a connecting rod 58 with a piston pin 57 by inserting a piston pin 57 into a piston 56 that has been previously fitted into the cylinder hole 34 when assembling the engine. The covers 32a and 33a also function as a cover for this hole. As shown in FIG. 2, the engine 7 is provided with the rear cylinder 23 slightly offset to the right in the direction of travel than the front cylinder 22, and the chain 54 is disposed in the left-hand space created thereby. This prevents it from protruding outward. Further, the support shaft 13 is made separately for the left and right parts, and a space is provided between them, so that the cylinder head 35
A part of the rear arm 12 is accommodated in the space to prevent interference between the front part of the rear arm 12 and the rear cylinder 23. Therefore, it is possible to position the engine 7 at the rear, thereby preventing the wheelbase from becoming too long. In addition, the rear arm 12 has a channel 60 made of a steel plate to increase the rigidity of the left and right legs 1.
2a, and is reinforced by welding a reinforcing frame 61 made of a thin steel pipe to the lower front surface.
62 is a shaft hole of the support shaft 13, and 63 is a support hole of the rear axle. Next, the operation of the embodiment will be explained. First, when the electric motor 43 for starting is activated, its rotation rotates the electric machine shaft 42 via the one-way clutch 45, and further rotates the crankshaft 31 via the chain 38. As a result, the air flows through the intake pipe 25a into the inner surface of the cylindrical filter member 25b installed in the air cleaner 25, and after being passed there, the air is divided back and forth and the flow rate is adjusted by each vaporizer 24. At the same time, an appropriate amount of fuel is added to form a mixture with a predetermined air/heat ratio, which is then sucked into the cylinder.
After the fuel is burned, the engine continues to operate on its own without relying on the electric motor 43.

As described above, in this invention, the axes of the front and rear cylinders are arranged above the support shaft in a substantially horizontal direction, and the transmission is arranged on the lower surface of the crank chamber in front of the support shaft. Therefore, interference between the rear cylinder and the rear arm is reduced, and the engine can be displaced rearward to a position where a part of the rear cylinder reaches above the support shaft of the rear arm and supported on the vehicle body frame. Therefore, interference between the front cylinder and the front wheel is reduced, so the wheelbase can be shortened as a whole. Additionally, since the transmission is installed on the underside of the crank chamber, it hangs in front of the support shaft, which prevents the vehicle's center of gravity from becoming too high even though the front and rear cylinders are positioned relatively upward. There is an effect.

Furthermore, if a heavy starter motor or generator is placed in front of the transmission on the underside of the front and rear cylinders, the center of gravity of the vehicle can be further lowered, and even if the engine is mounted at the rear, the load required for the front wheels can be reduced. It becomes possible to load In addition, if a horizontally opposed engine is divided into front and rear cylinders on the axis of the crankshaft, and the transmission case is integrated into the bottom of each case, the number of large parts that make up the case can be reduced, reducing the weight of the engine and reducing costs. can be reduced.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a side view of a motorcycle, and FIG. 2 is a partially cutaway plan view of the main parts showing its drive system.
FIG. 3 is an enlarged plan view of the engine with a part cut away, FIG. 4 is a sectional view thereof, FIG. 5 is a sectional view thereof, and FIG. 6 is a sectional view thereof.
7 is a cross-sectional view of FIG. 6, and FIG. 8 is an external view of the rear arm 12. 1...Vehicle frame, 10...Bracket, 12...
Rear arm, 13... Support shaft, 22... Front cylinder,
23...Rear cylinder, CL...Axis of each cylinder.

Claims (1)

[Claims] 1. The base end of a rear arm that supports the rear wheel is rotatably supported by a support shaft near the rear end of the main column of the vehicle body frame extending rearward from the steering shaft tube, and a crank chamber is installed below the main column. In an engine equipped with a horizontally opposed engine having front and rear cylinders including a front cylinder extending forward and a rear cylinder extending rearward, the axes of the front and rear cylinders are arranged above the support shaft in a substantially horizontal direction. , a motorcycle in which a transmission is disposed on a lower surface of the crank chamber in front of the support shaft;