JPH0771948B2 - Motorcycle - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a motorcycle including a power unit in which an engine and a mission are integrated.

(Prior Art) In a motorcycle of this type, as seen in JP-A-57-114769, a rear frame is extended above the engine portion of a power unit, and a carburetor is attached to the upper portion of the engine portion, to which an air cleaner is attached. It is common to connect

(Problems to be Solved by the Invention) As described above, in the case where the carburetor and the air cleaner case are arranged in the upper part of the engine, a space for the swing stroke of the power unit is required between these parts and the rear frame. Especially, since the air cleaner case is bulky and is located above the carburetor or at the rear of the carburetor with a large swing width, it is not possible to use a large capacity air cleaner and the cleaning element replacement frequency is low. There is a problem that becomes high.

An object of the present invention is to solve this problem.

(Means for Solving the Problem) The present invention has an object to solve the above-mentioned problems, and a means thereof is to integrally provide a mission case at a rear portion of an engine section with a cylinder center line in the front-rear direction. In a motorcycle that constitutes a power unit and has an engine portion positioned between the front and rear wheels to pivotally support the power unit on the vehicle body, a transmission case is continuously provided with a step on the side of the engine portion. The air cleaner case is arranged in front of the mission case and on the side of the engine portion within the width of the step of the mission case.

(Operation) With the above configuration, the air cleaner case can have a volume substantially equal to the large space formed by the front side of the engine section in front of the mission case and the front side of the projection of the mission case. A cleaner element with large capacity and large capacity can be installed.

(Example) Next, this invention is demonstrated about the Example shown in figure.

In the drawings, (1) shows a vehicle body or frame having a front wheel (2), a rear wheel (3) and a saddle (4) on an upper side of an intermediate portion, and the vehicle body (1) has a shaft support portion (1a) on a lower side of the intermediate portion. And a pair of rear forks (1b) extending rearward, and a pedal sprocket (7) attached to a pedal crankshaft (6) having pedal arms (5) (5) at both ends pivotally supported by the shaft support (1a). The rear wheel (3) is attached to drive the rear wheel (3) through the chain (8) by the rotation of the chain sprocket (7), and further the shaft supporting portion (1a) of the pedal crankshaft (6) of the vehicle body (1). A power unit (9) is installed on the lower side of the pedal arm (5) (5), which extends rearward and is located in a gap between the pedal arms (5) (5), and the rear wheel (3) can be freely driven by the power unit (9). A motorcycle with a built in.

To explain this in more detail, the power unit (9) uses, for example, a horizontal and vertical two-cycle engine in which a cylinder portion (9a) is arranged in front of a crankcase (9b) as shown in FIG. , A rear side transmission case (9c) incorporating a planetary reduction gear (10) is attached to a side surface of the crankcase (9b), and the crankcase (9b) is attached to a rear end portion of the mission case (9c). An output shaft (11) protruding into the rear space of the vehicle and a drive roller (12) attached thereto, and the power unit (9) is arranged with a pair of left and right pedal arms (5) (5). It is housed in a gap and is pivotally supported on the vehicle body (1) by hanger bolts (13) arranged in parallel under the pedal crankshaft (6) in its entirety, and its rear part is lifted by a wire-operated lifting machine (14). Suspend and lift By operating the machine (14), the power unit (9) can be swung up and down about the hanger bolt (13), and when the power unit (9) is swung upward, the drive roller (12) causes the rear wheel (3) to move. The rear wheel (3) is driven by the power unit (9) by being pressed against the tire surface.

Here, according to the present invention, the arrangement gaps shown in FIGS.
As clearly shown in the figure, the cylinder portion (9a) of the power unit (9) is sandwiched and the chain sprocket (7) is arranged on one side thereof and the air cleaner case (15) is arranged on the other side thereof. Air cleaner case (15)
The crankcase (on the side wall of the cylinder part (9a) on the mission case (9c) side so as to fit the space in the space formed by the step between the cylinder part (9a) and the mission case (9c). Pin (16) protruding from 9b) (5th
(Fig.) And fix with stepped bolts (17). The air inlet is located on the lower surface of the inner side of the air cleaner case (15) near the exhaust port (18) of the lower surface of the cylinder (9a). (15a) is formed so that the intake air temperature can be raised by utilizing the exhaust heat to improve the engine startability.
A windbreak plate (19) is provided in front of a) so that the heating characteristics of the intake air can be further improved. In this case, the cooling fins (20) of the cylinder portion (9a) are arranged so as to be orthogonal to the opening direction of the air inlet (15a), and the fins (20) are used to rectify the traveling wind after the engine is started. The air inlet (15
Prevent hot air from acting directly on a). Further, the engine unit (9) includes a carburetor (21) and a by-starter, that is, a control box (22) for a starting intake system, and the carburetor (21) is an inner surface of the air cleaner case (15). The inflow side connection tube (23) connected to the upper main air outlet (15b) and the outflow side intake pipe (25) connected to the intake port (24) formed in the crankcase (9b) of the power unit (9) A pair of left and right rear forks (1b) supported by the power unit (9) and extending rearward from the bearing portion (1a) above the intermediate portion of the power unit (9).
The power unit (9) is placed at a desired position between the (1b) and the carburetor (21) is lifted when the power unit (9) is set to a relatively high ground clearance, and the rear fork (1b) (1)
b) to prevent interference with the vehicle body (1) by inserting the lower half of the carburetor (21) into a step space between the crankcase (9b) and the mission case (9c). The rear part of the rear fork (1).
b) (1b), the crankcase (9b), the transmission case (9c), and the rear wheel drive chain (8) are vertically and horizontally enclosed to protect the carburetor (21) from foreign matter. The control box (22) is mounted on the head side of the cylinder (9a) so as to be interposed between the control box (22) and the air cleaner case (15). Sub air outlet (15c)
Through a secondary air inlet (22a) of the control box (22), and the other through a mixture gas generation part (21a) for a bai starter of the vaporizer (21). The air-fuel mixture inlet (22) of the control box (22)
b) Connect to the control box (2
The intake port (22c) of 2) is connected to the intake pipe (25) side, and a control valve (22e) communicating with the bimetal (22d) housed in the control box (22) allows the intake air-fuel mixture at engine startup. The concentration of was automatically increased or decreased according to the engine temperature.

The outside of the control box (22) is surrounded by the air cleaner case (15) so that it is less likely to be affected by outside air, and accurate control is performed according to the engine temperature. In addition, the connecting tube (2
The intake passage consisting of 3), the carburetor (21), and the intake pipe (25) is arranged in a line when viewed from above and below to minimize the intake resistance.

When the two-cycle engine having the intake port (24) in the crankcase (9b) is used as the power unit (9), the air cleaner case (15), the motorcycle starter device (22) are provided in the cylinder portion (9a). According to the above configuration in which the carburetor (21) is arranged on the upper side of the intermediate part of the unit (9), the intake passage including the by-starter is compacted on the upper side of the unit (9) from the front to the rear. It can be arranged in the position, which is advantageous.

Further, in the case shown in the figure, the temperature of the intake air does not drop due to water dripping from the rear fender (26) on the intake pipe (25) extending downward from the rear part of the carburetor (21).
The intake pipe (25) is covered from behind by a fender guard (27) attached to the rear fender (26).

In the drawing, (15d) is a cleaner element in the air cleaner case (15), (28) is a muffler connected to the exhaust port (18) through the exhaust pipe (29), (30) is a fuel tank, and (31) is An oil tank, (32) an oil pump provided at the rear of the mission case (9c), (33) and (34) an ratchet type one-way clutch and a generator provided in the transmission case (9c) for starting the engine, (35) Indicates a chain cover.

Next, to explain the operation, when power traveling by the power unit (9) is performed, the pedal arm (5) (5) is rotated and the unit (9) is swung upward while self-propelled, as described above. The drive roller (12) is brought into pressure contact with the rear wheel (3). With this, the engine is started by the rotational force of the rear wheel (3) via the roller (12) and the one-way clutch (33). After that, the rear wheel (3) is rotationally driven by the engine torque transmitted to the roller (12) through the reduction gear (10) to perform power traveling, and if the power traveling is continued, the cylinder portion ( Although the temperature of 9a) gradually rises, in the present invention, since the cylinder portion (9a) is sandwiched by the chain sprocket (7) and the air cleaner case (15) from both sides, the pants of the occupant and the like are kept in the cylinder portion (9a). )
Therefore, the pants and the like are not contaminated with mud or oil adhering to the cylinder portion (9a) or heated by heat.

(Advantages of the Invention) In the present invention, the air cleaner case is arranged so as to use the space formed by the stepped portion between the cylinder portion of the power unit and the mission case as described above, and to arrange the air cleaner case within the width of the mission case. There is an advantage that the power unit integrally provided with the case can be configured as a compact unit whose width does not increase.

Further, since the air cleaner case is located near the pivot point of the power unit, it has a small amount of swing and can be easily installed so as not to interfere with other members despite having a large capacity.

[Brief description of drawings]

FIG. 1 is a side view of an example of a bicycle of the present invention, FIG. 2 is a side view of a partial cut of the main part, FIG. 3 is a front view of a partial cut of the main part, and FIG. 4 is a partial cut of the main part. Top view, FIG. 5 is second
FIG. 5 is a cross-sectional plan view taken along the line VV of the figure. (1) …… Car body, (2) …… Front wheel (3) …… Rear wheel, (5) …… Pedal arm (6) …… Pedal crankshaft, (7) …… Chain sprocket (9) …… Power unit , (9a) …… Cylinder part (15) …… Air cleaner case

Claims (2)

[Claims] 1. A power unit is constructed by integrally providing a transmission case at a rear portion of an engine portion with a cylinder center line directed in the front-rear direction, and the engine portion is positioned between a front wheel and a rear wheel to mount the power unit on a vehicle body. In a two-wheeled vehicle that is swingably supported, a mission case is continuously installed with a step on the side of the engine section, and an air cleaner case is provided in front of the mission case and on the side of the engine section with a step width of the step. A motorcycle characterized by being arranged inside. 2. A carburetor is arranged at the rear of the air cleaner case, and a crank case is arranged at the rear of the carburetor, and these are communicated with each other in a substantially linear manner in an intake passage. The motorcycle according to the item.