JP2000025670A - Motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain the generation of a noise by tightening a cover to a transmission case stored a transmission mechanism and connected to the engine main body and constituting by a case main body in which an air cleaner case is connected integrally with the cover and a case cover tightened to the case main body. SOLUTION: A cover 41 is tightened by a screw member 42 on the outer surface of a first case member 24 in a transmission case 26 and the part except the recessed part 40 of the first case member 24 is covered by the cover 41. A carbureter 43 is arranged to an engine main body 20 and an air cleaner 44 is arranged on the rearside of the carbureter 43. The air cleaner case 45 of the air cleaner 44 is composed of a case main body 46 formed connectingly integrally with the cover 41 and a case cover 47 tightened to the case main body 46. Thereby, an excellent sound shielding effect can be obtained and the strength of the transmission case is ensured, moreover the capacity of the air cleaner can be ensured largely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motorcycle in which a power unit including an engine and a transmission mechanism for transmitting the power of the engine to a rear wheel is swingably supported on a body frame.

[0002]

2. Description of the Related Art Conventionally, such a motorcycle is disclosed in, for example, Japanese Patent Application Laid-Open Nos. 7-187050 and 7-2478.
It is already known from Japanese Patent Publication No. 54-54 and the like.

[0003]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 7-187.
In the device disclosed in Japanese Patent Publication No. 050, an air cleaner is disposed above the power unit. The air cleaner is arranged to avoid interference with a transmission case that houses a transmission mechanism, and to arrange a stay or the like that supports the air cleaner. It is difficult to secure a large capacity.

On the other hand, in the device disclosed in Japanese Patent Application Laid-Open No. Hei 7-247854, the transmission case is composed of a transmission case body and a transmission case cover fastened to the transmission case body, and the air cleaner case is constructed together with the case cover. The case main body is formed integrally with the transmission case cover to increase the capacity of the air cleaner. Moreover, since the weight increases if the case body is made of metal, the transmission case cover is divided into a metal part and a synthetic resin part, and the air cleaner of the transmission case cover is made of a synthetic resin part. The case body is integrally formed. However, if a part of the transmission case is made of synthetic resin, it is not possible to secure sufficient strength as the transmission case.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a motorcycle which can suppress the generation of noise from a transmission mechanism while securing a large capacity of an air cleaner while securing the strength of a transmission case. The purpose is to provide.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, a power unit comprising an engine and a transmission mechanism for transmitting the power of the engine to a rear wheel is provided on a body frame. In a motorcycle that is swingably supported, a cover that covers the transmission case is fastened to a transmission case that houses the transmission mechanism and that is connected to the engine body, and the air cleaner case of the air cleaner is integrally connected to the cover. And a case cover fastened to the case body.

According to such a configuration, since the transmission case is covered with the cover, the operation noise generated by the transmission mechanism in the transmission case is suppressed from being emitted to the outside by the cover, and an excellent sound insulation effect is obtained. be able to. In addition, since the case body that composes the air cleaner case and the case cover is integrally connected to the cover that is fastened to the transmission case, it is not necessary to make a part of the transmission case made of synthetic resin, ensuring the strength of the transmission case It is not necessary to consider the interference with the transmission case and the arrangement of the stay and the like for supporting the air cleaner, so that a large capacity of the air cleaner can be secured.

[0008] The invention according to claim 2 provides the above-mentioned claim 1.
In addition to the configuration of the invention described above, a recess is provided in the transmission case between the crankshaft of the engine and the axle of the rear wheel, and the case main body is provided with an enlarged portion accommodated in the recess. According to this configuration, the capacity of the air cleaner can be further increased.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

1 to 5 show an embodiment of the present invention. FIG. 1 is a side view of a scooter type motorcycle, FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1, and FIG. FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 1, and FIG. 5 is an enlarged sectional view taken along line 5-5 of FIG.

First, in FIG. 1, a body frame F of a scooter-type motorcycle V has a head pipe 12 for steering a front fork 11 on which a front wheel WF is suspended, and a down tube extending downward from the head pipe 12. 1
3, and a rear frame 14 which is connected to the lower end of the down tube 13 and extends rearward. The rear frame 14 has a front end connected to a lower end of the down tube 13 and extending substantially horizontally toward the rear side, and a pair of front frame parts 14a. It has a pair of intermediate frame portions 14b extending and a rear frame portion 14c interconnecting the rear ends of both intermediate frame portions 14b... And is formed in a substantially elliptical shape in plan view.

The vehicle body frame F is covered by a vehicle body cover 16 having a floor board 16a for supporting the driver's feet. At the rear of the vehicle body cover 16, a seat 17 on which the driver sits is provided.

The rear wheel WR is rotatably supported by a rear portion of a power unit P which is swingably supported on a vehicle body frame F. The power unit P includes a two-cycle forced air-cooled engine E, E output from the rear wheel WR
And a continuously variable transmission M as a transmission mechanism for transmitting power to the transmission. Thus, the front portion of the power unit P can swing around an axis parallel to the rotation axis of the rear wheel WR to both intermediate frame portions 14b of the rear frame 14 in the body frame F via a link mechanism (not shown). Supported as
A rear cushion 19 is provided between a rear portion of the power unit P and the rear frame 14.

In FIG. 2, the engine body 20 of the engine E is configured such that the axis of a crankshaft 22 supported by a crankcase 21 which is a part of the engine body 20 is parallel to the rotation axis of the rear wheel WR. , Is arranged in front of the rear wheel WR.

The crankcase 21 is integrally provided with a case portion 23 extending to one side of the rear wheel WR, and a first portion fastened to the case portion 23 on a side opposite to the rear wheel WR. A case member 24, a second case member 25 fastened to a rear portion of the case portion 23 on the rear wheel WR side,
A transmission case 26 is formed by the case portion 23, and is a continuously variable transmission provided between the crankshaft 22 protruding from the crankcase 21 and the axle 27 of the rear wheel WR rotatably supported at the rear of the transmission case 26. The transmission M is housed in the transmission case 26.

The continuously variable transmission M has a driven transmission pulley 28 connected to the crankshaft 22, and a driven shaft 29 having an axis parallel to the crankshaft 22 and rotatably supported at the rear of the transmission case 26. And a driven transmission pulley 30 paired with the drive transmission pulley 28, a centrifugal clutch 31 provided between the driven transmission pulley 30 and the driven shaft 29, and a drive and driven transmission pulley 28, 30 And a reduction gear train 33 provided between the axle 27 and the driven shaft 29 of the rear wheel WR.

The drive-side transmission pulley 28 is connected to the crankshaft 22.
And a movable pulley half 35 mounted on the crankshaft 22 slidably in the axial direction. A V-shaped annular groove 36 is formed between the fixed and movable pulley halves 34 and 35, and the V-belt 32 is inserted into the annular groove 36. On the back of the movable pulley half 35, a ramp plate 37 is fixed to the crankshaft 22, and this ramp plate 37 and the movable pulley half 35
A plurality of weight rollers 38 are stored in a floating state. When the number of revolutions increases when the crankshaft 22 rotates, the weight roller 38 receiving the centrifugal force moves radially outward and moves the movable pulley half 35 in a direction to approach the fixed pulley half 34, Thereby, the contact radius of the V-belt 32 to the two pulley halves 34, 35 can be increased.

Referring also to FIGS. 3 to 5, at the position corresponding to the intermediate portion between the crankshaft 22 and the axle 27, on the outer surface side of the first case member 24 in the transmission case 26,
A concave portion 40 that is open at both upper and lower ends and extends vertically is provided.

On the other hand, a cover 41 made of a synthetic resin is fastened to the outer surface of the first case member 24 of the transmission case 26 by a plurality of screw members 42, 42,. The portion excluding the concave portion 40 is covered.

As shown in FIGS. 1 and 3, a carburetor 43 is disposed at a position above the engine body 20, and an air cleaner 44 is disposed behind the carburetor 43.

The air cleaner case 45 of the air cleaner 44 is composed of a case body 46 integrally formed with the cover 41 and made of synthetic resin, and a case cover 47 fastened to the case body 46.

The case body 46 has a case body main portion 46a which is open on the side opposite to the rear wheel WR and is integrally connected to the upper portion of the cover 41, and the first case member 2
4, a first enlarged portion 46b extending downward from a lower portion of the case main body 46a to be housed in the concave portion 40 and integrally connected to the cover 41, and a rear wheel W extending from the front of the case main body 46a.
A second expanding portion 46c that projects to the front side of the R is integrally provided. Thus, the case body main portion 46a and the first expanding portion 4
6b is formed in a substantially T-shape and opens to the opposite side to the rear wheel WR, and the second expanding portion 46c is formed in a cylindrical shape with a closed end.

The case cover 47 is formed in a substantially T-shape so as to close an opening opposite to the rear wheel WR of the case body 46. The case cover 47 is formed by a plurality of screw members 48, 48,. It is fastened to 46.

The main part 4 of the case body in the case body 46
A receiving portion 49 is integrally provided on the inner peripheral surface of 6a so as to protrude inward.
The peripheral portion of the filter medium 52 partitioned into the unpurified chamber 50 on the case cover 47 side and the purified chamber 51 is received by the receiving portion 49. The case cover 47 includes a plurality of pressing portions 53 that sandwich the peripheral portion of the filter medium 52 with the receiving portion 49.
53 are integrally provided. Therefore, by fastening the case cover 47 to the case body 46 in a state where the peripheral portion of the filter medium 52 is in contact with the receiving portion 49, the filter medium 52 is sandwiched between the case body 46 and the case cover 47. .

The main part 4 of the case main body in the case main body 46
An air inlet 54 for introducing air from outside into the unpurified chamber 50 is provided at the rear of the case body 4a.
A conduit 55 that guides the air in the purification chamber 51 to the vaporizer 43 is connected to the front of the second expanding portion 46c in FIG.

Next, the operation of this embodiment will be described. The first case of the transmission case 26 accommodating the continuously variable transmission M is described below.
Since the case member 24 is covered with the cover 41 fastened to the first case member 24, the operation noise generated in the continuously variable transmission M in the transmission case 26 is prevented from being emitted to the outside.
Can be suppressed.

The air cleaner case 45 of the air cleaner 44 comprises a case body 46 and a case cover 47 fastened to the case body 46. The case body 46 is formed integrally with the cover 41. Therefore, it is not necessary to make a part of the transmission case 26 made of synthetic resin, and the strength of the transmission case 26 can be ensured. In addition, the interference with the transmission case 26 and the arrangement of the stay and the like for supporting the air cleaner 44 are reduced. There is no need to consider this, and a large capacity of the air cleaner 44 can be secured.

Moreover, the first case member 2 of the transmission case 26
4, a concave portion 40 is provided between the crankshaft 22 and the axle 27 of the rear wheel WR, and a first expanding portion 46b accommodated in the concave portion 40 is provided in the case body 46 of the air cleaner case 45. Therefore, the capacity of the air cleaner 44 can be further increased, and the case main body 46 of the air cleaner case 45 is also provided with a second enlarged portion 46c that projects toward the front side of the rear wheel WR. Can be further increased.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do.

[0030]

As described above, according to the first aspect of the present invention, it is possible to obtain an excellent sound insulation effect by suppressing the operation noise generated by the transmission mechanism in the transmission case from being emitted to the outside by the cover. Instead, it is not necessary to make a part of the transmission case made of synthetic resin, and the strength of the transmission case is ensured, and the capacity of the air cleaner can be ensured large.

According to the second aspect of the invention, the capacity of the air cleaner can be further increased.

[Brief description of the drawings]

FIG. 1 is a side view of a scooter type motorcycle.

FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG.

FIG. 3 is an exploded perspective view of a transmission case and an air cleaner.

FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 1;

FIG. 5 is an enlarged sectional view taken along line 5-5 of FIG. 1;

[Explanation of symbols]

 Reference Signs List 20 engine body 22 crankshaft 26 transmission case 27 axle 40 recess 41 cover 44 air cleaner 45 air cleaner case 46 case body 46b ··· Enlarged part 47 ··· Case cover E ··· Engine F ··· body frame M ······································································································································································· ··Rear wheel

Claims (2)

[Claims] 1. A power unit (P) comprising an engine (E) and a transmission mechanism (M) for transmitting the power of the engine (E) to a rear wheel (WR) swings on a body frame (F). In a motorcycle that is supported as possible, a cover (41) that covers the transmission case (26) is fastened to a transmission case (26) that houses the transmission mechanism (M) and continues to the engine body (20), and an air cleaner. The air cleaner case (45) of (44) comprises a case body (46) integrally connected to the cover (41) and a case cover (47) fastened to the case body (46). Motorcycle. 2. A crankshaft (2) of the engine (E).
2) A recess (40) is provided in the transmission case (26) between the axle (27) of the rear wheel (WR) and the case body (46) is housed in the recess (40). Motorcycle according to claim 1, characterized in that an enlarged part (46b) is provided.