JPS58174072A - Motorcycle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention The present invention is equipped with a horizontally opposed engine having a front cylinder extending forward across the crank chamber and a rear cylinder extending rearward, with the axis of each cylinder pointing in the longitudinal direction of the vehicle. This article relates to motorcycles that have been developed.

In general, horizontally opposed engines have a small length in the crankshaft direction, but the cylinder is large in the axial direction, so
Motorcycles equipped with this in the manner described above may have an excessively large distance between the axles of the front and rear wheels, or may have an air cleaner carburetor embedded in the fuel tank or the bottom of the passenger seat, reducing the fuel tank capacity. Friend 9: The cushion tends to become too thin.

In order to eliminate such problems, the present invention is characterized in that the engine is mounted on the vehicle body frame in nine ways, with the axis of each cylinder tilted from above the support shaft of the rear arm toward the front and below.

The present invention will be explained below with reference to illustrated embodiments.

The motorcycle of the example is assembled by welding steel pipes and has a body frame 1.
t- have. Reference numeral 2 denotes a steering shaft tube located at the front end of the vehicle body frame, which supports a front wheel 4 through a front fork 3 so as to be able to turn left and right. The body frame 1 has a main pillar 5 extending rearward from the steering axis w.
and a down tube 6 extending downward, the former S supports the rear part of the engine 7, the latter 6 supports the front part. Reference numerals 8 and 9 indicate plackets that are fixed to the vehicle body frame with engine 7 bolts.

A rear arm 12 for supporting a rear wheel 11 is supported at the lower end of the main column 5 by a support shaft 13 via a bracket 1G so as to be vertically swingable. A seat support frame 14 extending further rearward of the vehicle body frame 1 and its reinforcing frame 15 are assembled by welding, and the seat support frame 14 and the rear arm 1
A buffer spring 16 for the rear wheel 11 is installed between the rear wheel 11 and the rear wheel 11. 1T is constructed on the upper surface of the vehicle body frame 1 and has nine fuel tanks, 18
is the passenger seat.

The engine 'T 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.
23fl is arranged so that its axis MCL extends forward and downward from above the support shaft 13.

Further, a carburetor 24,24 is provided on the top surface of each cylinder, and these communicate with a common air cleaner 25. 25a is an air intake pipe, and 25b is a two-paper f-retraction member. An exhaust pipe 26 extends downward from the front cylinder 22 and opens into the atmosphere via the first muffler 2T and the second muffler 28. Note that the exhaust pipe 21 of the rear cylinder 23
1 Extends downward from the front of the support shaft 13 and is directly connected to the tuna 1 silencer 2T.

Engine 7Vi More specifically, as shown in FIGS. 2 and 3, the crankshaft 31 arranged on the left and right with respect to the direction of travel is connected to the front case 32 and rear case 3 that constitute the crank chamber 21.
It is held between 3 and 3. Each case 32.33 is 2 each
It is designed as a cylinder block with individual cylinder bores 34,34. 35 is the cylinder head, 36
is its cover. A timing shaft 3T that interlocks with the crankshaft 31 is pivotally supported on the joint surface between the front case 32 and the rear case 33.

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. A clutch chamber 21b is formed between the right outer surface of the crank chamber 21 and a cover 33a covering it, and a clutch 49 is attached to an input shaft 47 protruding into the clutch chamber 21b.
is provided.

The clutch 4'9 is a pinion 52 fixed to the crankshaft.
While being decelerated by a gear train consisting of a large filtration gear 53 connected to a clutch 49, the input shaft 4T is driven. The output shaft 48 of the transmission drives the rear wheels 11 via a chain 54, as is well known. Engine 7Vi [As shown in Figure 2, the temporary cylinder 23 is provided slightly to the right in the direction of travel from the front cylinder 22, and the chain 54 is arranged in the space on the left side created thereby, so that the chain 54 is placed outside, This prevents it from protruding too far in the direction. Further, the support shaft 13 is made separately for the left and right parts, and a space is provided between them, and a part of the cylinder head 35 is housed in the space, so that there is no interference between the front part of the rear arm 12 and the rear cylinder 23. is prevented. Therefore, engine T
This allows the vehicle to be mounted at the rear, preventing the wheelbase from becoming too long.

Next, the operation of the embodiment will be explained. First, when the engine T starts, atmospheric air flows through the intake pipe 25m into the inner surface of the cylindrical retractable member 2Sb installed in the air cleaner 25, where it passes through the air, and then is divided into the front and back to each The flow rate is adjusted by the carburetor 24, and at the same time an appropriate amount of fuel is added to form a mixture with a predetermined air-fuel ratio, which is sucked into the cylinder and combusted. The rotation of the crankshaft 31 is controlled by the input shaft 47 of the transmission. Output shaft 48 and chain 5
4, the wheels 11 are driven.

In this invention, as described above, the front and rear cylinders are arranged so that their axes are inclined from above the support shaft to the front and below, so that interference between the rear cylinder and the rear arm support shaft is reduced, and Since interference with the fuel tank of the carburetor and air cleaner above the engine is reduced, the engine can be displaced rearward to a position where a portion of the rear cylinder reaches above the support shaft of the rear arm and supported on the vehicle body frame.

Therefore, the wheelbase can be shortened when viewed as a whole. Also, the fuel tank located above the engine/
This has the effect of making it possible to sufficiently increase the capacity of the tank.

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 grant Also,
If a horizontally opposed engine is divided into front and rear cylinders along 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 will be reduced, making the engine lighter and reducing costs. becomes possible.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention. Fig. 1 is a side view of a motorcycle, Fig. 2 is a plan view of its drive system, and Fig. 3 is a partially cutaway plan view of the main parts. FIG. 2 is an enlarged cross-sectional view of the main parts of the engine. 1...Vehicle frame, 12...Rear arm, 13...
...Spindle, 22...Front cylinder, 23.Fist/rear cylinder, CL...Axis of Φ front and rear cylinders. Patent Applicant: Yamaha Motor Co., Ltd. Agent Masa Yamayo #1 (and 1 other person)

Claims (1)

[Claims] A horizontally opposed engine is provided with a rear arm rotatably supported at the rear of a vehicle body frame via a support shaft, and a front cylinder extending forward and a rear cylinder extending rearward across a crank chamber below the vehicle body frame. A motorcycle in which the cylinder axes of the front cylinder and the rear cylinder are inclined from above the support shaft to the front and downward.