JPH07247854A - Integral type power unit - Google Patents

Abstract

PURPOSE:To provide an integral type power unit, having an air cleaner, which is constituted to prevent interference with a peripheral device as a necessary content amount is ensured. CONSTITUTION:In a power unit 33 comprising an engine; and a transmission case 36 to transmit an engine output to rear wheels 38, the transmission case 36 is formed in such a manner that a transmission case body 54 and a transmission case cover 55 are dividably combined together. Meanwhile, an air cleaner 58 formed in a state that a cleaner case body 58a and a cleaner case cover 58b are dividably combined together is arranged on the upper part of the transmission case 36, and the transmission case cover 55 and a cleaner case body 58a are integrally molded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power unit integrally provided with an engine and a power transmission system, and more particularly to an integrated power unit having a conduction case cover and a cleaner case.

[0002]

2. Description of the Related Art Some small vehicles such as scooters have a power unit. As shown in FIG. 4, the power unit 1 is configured by integrally combining an engine 2 and a power transmission system such as a transmission case 4 and a transmission mechanism 5 that transmit the output of the engine 2 to the rear wheels 3, and the power unit 1 is formed. For example, the front side of 1 is swingably attached to the vehicle body frame 6, and the rear side is attached to the vehicle body frame 6 via the rear shock absorber 7 so that it also serves as a swing arm.

A V-belt transmission mechanism and a centrifugal clutch mechanism for transmitting an engine output are provided inside the conductive case 4 and are closed by a conductive case cover 8. The conductive case cover 8 needs to be strong enough to support the kick starter shaft 9, for example, and therefore is made of a strong material.

The engine 2 includes engine intake systems 10 and 11 including a carburetor 10 and an air cleaner 11.
Are connected. Since the engine 2 swings, the engine intake systems 10 and 11 are generally fixed to the upper part of the conduction case 4 with a screw 12 or the like and swinged together with the engine 2.

By the way, conventionally, blow-by gas generated in the engine 2 is blown by using an air cleaner 11 using a hose or the like.
Had been guided inside.

[0006]

The air cleaner 11 is
In order to improve the intake efficiency of the engine 2, a large internal capacity is desired. However, if the air cleaner 11 is largely extended upward, it may interfere with an upper device when the power unit 1 swings. Therefore, the air cleaner 11 is usually extended rearward to secure a necessary internal capacity. As shown in FIG. 5 (a cross-sectional view taken along the line VV in FIG. 4), when the air cleaner 11 is extended rearward, the air cleaner 11 interferes with the rear shock absorber 7. Therefore, the recess 13 is provided in the air cleaner 11 to provide the shock absorber. 7
Avoid interference with.

However, if the recess 13 is provided in the air cleaner 11, the air passage in the air cleaner 11 is partially narrowed, and the air flow resistance increases, which may adversely affect the intake efficiency of the engine 2.

Further, since the upper portion of the conductive case 4 is curved and has a non-linear shape, a gap 14 is formed between the air cleaner 11 and the conductive case 4, resulting in a waste of space.

Further, since the metal material is used as the strength material used for the conductive case cover 8, it contributes to the weight increase.

In order to introduce the blow-by gas generated in the engine 2 into the air cleaner 11 by using a hose or the like, it takes a lot of time to mount the hose or the like, and the maintainability at the time of maintenance is not good.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide an integrated power unit having an air cleaner that does not interfere with peripheral equipment while securing a necessary internal capacity. To do.

Another object of the present invention is to provide an integrated power unit which can reduce the weight.

Still another object of the present invention is to provide an integrated power unit that does not require a hose or the like for introducing blow-by gas generated in the engine to an air cleaner.

[0014]

In order to solve the above-mentioned problems, an integrated power unit according to the present invention has an engine and a conductive case for transmitting the output of the engine to the rear wheels. In the power unit integrally provided with, the conductive case is configured by combining the conductive case body and the conductive case cover in a separable manner, while the cleaner case body and the cleaner case cover can be divided in the upper part of the conductive case. An air cleaner configured by combining the above is provided, and the conduction case cover and the cleaner case body are integrally molded.

Further, in order to solve the above-mentioned problems, as described in claim 2, the conductive case cover is configured to be separable into front and rear, and the front case cover is formed of a metal material while the rear case is formed. The cover is formed integrally with the cleaner case body from a resin material.

Further, in order to solve the above-mentioned problems,
As described in claim 3, the inside of the crankcase of the engine and the inside of the conduction case are communicated with each other through a breather device, and a breather hole is provided at a portion where the inside of the cleaner case cover and the conduction case cover are in contact with each other. And the inside of the air cleaner and the inside of the conduction case are connected by the breather hole.

[0017]

According to the present invention having the above-mentioned structure, in the power unit integrally provided with the engine and the conductive case for transmitting the output of the engine to the rear wheels, the conductive case divides the conductive case body and the conductive case cover. The conduction case cover and the cleaner case body are integrally formed on the conduction case, while an air cleaner is provided on the top of the conduction case so as to be separably combined with the cleaner case body and the cleaner case cover. Since it is molded as described above, it is possible to provide an integrated power unit having an air cleaner that does not interfere with peripheral devices while securing a necessary internal volume.

Further, since the conductive case cover is configured to be separable into the front and rear, and the front case cover is formed of a metal material, the rear case cover is formed of a resin material integrally with the cleaner case body. That is, the weight of the power unit can be reduced.

Further, the inside of the crankcase of the engine and the inside of the conduction case are communicated with each other through a breather device, and a breather hole is formed at a portion where the inside of the cleaner case cover and the above-mentioned conduction case cover are in contact with each other. Since the inside of the air cleaner and the inside of the conductive case are communicated with each other by the breather hole, the blow-by gas generated in the engine can be guided to the air cleaner without using a hose or the like.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a left side view showing an example of a scooter type vehicle to which the present invention is applied, and a part thereof is shown in a crushed state.

In FIG. 1, the scooter type vehicle 21 has a body frame 22. The body frame 22 includes a down tube 22a, and a pair of left and right rear frames 22b extending rearward and upward from the rear end side of the down tube 22a. Composed of. The rear frame 22b is bent near the middle thereof and extends rearward and upward.

A head pipe 22c is provided in front of the down tube 22a, and a front fork 24 and a handle bar 25 for rotatably supporting the front wheel 23 are provided on the head pipe 22c. Is steered so as to be rotatable left and right.

An article storage chamber 26 capable of accommodating a helmet or the like is provided above the rear frame 22b, and an operation seat 27 is installed above the article storage chamber 26 so as to be openable and closable.
The vehicle body frame 22 is covered with a vehicle body cover 28, and a rear combination lamp 29 is provided at the rear end of the vehicle body cover 28. Further, a space between the driving seat 27 and the handlebar 25 is curved downward in a large U shape, and a step board 30 on which the foot of an occupant is placed is mounted on this portion.
Is provided.

A pair of left and right stays 31 are provided in the lower center of the body frame 22, and a front portion of a power unit 33 is pivotally attached to a pivot shaft 32 provided between the stays 31 via a link 34. It The power unit 33 includes an engine 35 and a conductive case 36 extending rearward from one side of the engine 35. The conductive case 36 also serves as a swing arm and is elastically supported by the rear frame 22b by a rear shock absorber 37. The rear wheel 38, which is a driving wheel, is held at the rear end of the conductive case 36.

FIG. 2 is a horizontal sectional view of the power unit 33 taken along the line II-II of FIG. 1, and the engine 35 is mounted on the front portion of the power unit 33. The engine 35 mainly includes a crankcase 39, a cylinder 40 and a cylinder head 41, and the reciprocating motion of a piston 42 in the cylinder 40 causes a crankshaft 44 to rotate via a connecting rod 43. Also, the engine 35
For example, a conductive case 36 is provided on the left side in the figure.

By the way, the piston 42 in the cylinder 40
In the compression process of the air-fuel mixture, the high-pressure compressed air-fuel mixture partially leaks from the gap between the piston 42 and the cylinder 40 and flows into the crankcase 39. The air-fuel mixture that flows into the crankcase 39 is generally referred to as blow-by gas, and the rotation of the engine 35 that is operating at high speed is suddenly reduced, or the cylinder 40 is worn and the gap between the piston 42 increases. As a result, blowby gas is generated in a particularly large amount.

Since blow-by gas is one source of air pollution, it is usually necessary to recirculate the blow-by gas to the engine intake system and then send it back into the cylinder 40 for re-combustion. Because it is mixed with the oil present in the mist,
For example, only a gas is guided to the outside of the crankcase 39 using a breather device having a maze structure.

The power unit 33 applied to this embodiment
The inside of the crankcase 39 and the inside of the conduction case 36 are communicated with each other via the breather device (not shown) described above.

A drive pulley 46 of a V-belt transmission mechanism 45 provided in the transmission case 36 is mounted on the left end side of the crankshaft 44, and driven by a V-belt 47 of the V-belt transmission mechanism 45. Pulley 4
The driving force of the engine 35 is transmitted to the engine 8.

The driven pulley 48 is the power unit 3
3 is rotatably supported by a driven shaft 49 provided at the rear portion of the drive shaft 3. The rotational driving force transmitted to the driven pulley 48 is transmitted to the driven shaft 49 via the centrifugal clutch mechanism 50.

The driven shaft 49 is connected to the rear axle 52 through a transmission mechanism 51 which is a reduction gear mechanism and a power transmission device, and the rotation of the engine 35 is transmitted to the rear wheels 38 via the transmission mechanism 51. ing.

A kick starter device 53 is provided between the drive pulley 46 and the driven pulley 48. The kick starter device 53 mainly includes a kick lever 53a, a kick shaft 53b rotated by the kick lever 53a, and a starter idle gear 53c for transmitting the rotation of the kick shaft 53b to the crankshaft 44. It

The conduction case 36 is constructed by combining a conduction case main body 54 integrally extending rearward from the crankcase 39 and a conduction case cover 55 in a separable manner. Further, the conductive case cover 55 is configured to be separable into front and rear. The front case cover 55F includes the kick shaft 53b.
In order to support the starter idle gear 53c, it is molded using a light metal such as aluminum or a light alloy material,
Ensure the required strength. On the other hand, the rear case cover 55R
Is only for covering the centrifugal clutch mechanism 50 and does not require strength as much as the front case cover 55F.
It is molded using a resin material such as BS.

By the way, as shown in FIG.
A carburetor 57 constituting an engine intake system 56 is connected to the valve 5, and an air cleaner 58 also constituting the engine intake system 56 is connected to the upstream side of the carburetor 57. The carburetor 57 and the air cleaner 58 are arranged above the power unit 33 and swing together with the power unit 33.

FIG. 3 is a sectional view of the air cleaner 58 taken along the line III-III in FIG. 1. As shown in the drawing, the air cleaner 58 mainly includes a cleaner case main body 58a, a cleaner case cover 58b, and a filter element 58c.
Composed of and.

The cleaner case body 58a is formed directly above the conduction case 36 and integrally with the rear case cover 55R of the conduction case 36 using a resin material such as ABS. Then, the filter element 58c is mounted in the cleaner case main body 58a, and the cleaner case cover 58 is attached.
Blocked with b. The inside of the cleaner case cover 58b communicates with the atmosphere via an air intake (not shown), while the inside of the cleaner case body 58a communicates with the carburetor 57 via a connection hose 59 (see FIG. 1).

In the cleaner case cover 58b,
A breather hole 60 is formed at a portion in contact with the rear case cover 55R of the conduction case 36, and the inside of the air cleaner 58 and the inside of the conduction case 36 are communicated with each other by the breather hole 60.

Next, the operation of this embodiment will be described.

The cleaner case body 58a is connected to the conductive case 3
By being integrally formed with the rear case cover 55R of No. 6, the gap existing between the air cleaner 58 and the conductive case 36 in the related art can be effectively used as the capacity of the air cleaner 58. As a result, it is not necessary to extend the air cleaner 58 rearward to secure the capacity, and the air cleaner 58 does not interfere with the rear shock absorber 37. Therefore, it is not necessary to provide a recess in the air cleaner 58,
It does not adversely affect the intake efficiency of the engine 35.

Furthermore, the screw or the like for fixing the air cleaner 58 to the conduction case 36 as in the conventional case is unnecessary,
The number of parts, man-hours for assembly, manufacturing cost, etc. can be reduced.

The front case cover 55F of the conductive case 36 supporting the kick shaft 53b and the starter idle gear 53c is molded from a light metal such as aluminum or a light alloy material, and the conductive case covering the centrifugal clutch mechanism 50 is formed. Since the rear case cover 55R of 36 is molded integrally with the cleaner case main body 58a using a resin material such as ABS, compared with the conventional case where the entire conductive case cover 55 is molded with a metal material, the conductive case cover 55R
The weight of can be reduced. As a result, the weight of the entire power unit 33 can be reduced.

Further, the inside of the crankcase 39 and the inside of the conduction case 36 are communicated with each other through a breather device (not shown), and the inside of the cleaner case cover 58b is in contact with the rear case cover 55R of the conduction case 36. Since the breather hole 60 is formed in the air cleaner 58 and the inside of the air cleaner 58 and the inside of the conduction case 36 are communicated with each other by the breather hole 60,
The blow-by gas generated in the crankcase 39 is guided into the air cleaner 58 via the inside of the conduction case 36 without using a hose or the like, so that the hose or the like is unnecessary and the number of parts can be reduced, and at the time of maintenance. The maintainability of etc. will be improved.

Although the above-described embodiment shows an example in which the present invention is applied to the scooter type vehicle 21, it can be applied to any vehicle using a power unit.

[0045]

As described above, according to the integrated type power unit of the present invention, in the power unit integrally provided with the engine and the conductive case for transmitting the output of the engine to the rear wheels, the conductive case is conductive. The case main body and the conductive case cover are separably combined, while the conductive case is provided with an air cleaner formed on the upper part of the conductive case by the separable combination of the cleaner case main body and the cleaner case cover. Since the cover and the cleaner case body are integrally formed, it is possible to provide an integrated power unit having an air cleaner that does not interfere with peripheral devices while ensuring a necessary internal capacity.

Further, since the conductive case cover is configured to be separable into the front and rear, and the front case cover is formed of a metal material, the rear case cover is formed of a resin material integrally with the cleaner case body. That is, the weight of the power unit can be reduced.

Further, the inside of the crankcase of the engine and the inside of the conduction case are communicated with each other through a breather device, and a breather hole is formed at a portion where the inside of the cleaner case cover and the above-mentioned conduction case cover are in contact with each other. Since the inside of the air cleaner and the inside of the conductive case are communicated with each other by the breather hole, the blow-by gas generated in the engine can be guided to the air cleaner without using a hose or the like.

[Brief description of drawings]

FIG. 1 is a left side view of a scooter type vehicle showing an embodiment of an integrated power unit according to the present invention.

FIG. 2 is a horizontal sectional view of the power unit taken along the line II-II in FIG.

3 is a cross-sectional view of the air cleaner taken along the line III-III in FIG.

FIG. 4 is a view showing the shape of a conventional air cleaner.

5 is a cross-sectional view taken along the line VV of FIG.

[Explanation of symbols]

 21 scooter type vehicle 33 power unit 35 engine 36 transmission case 38 rear wheel 39 crankcase 45 V belt transmission mechanism 50 centrifugal clutch mechanism 51 mission mechanism 53 kick starter device 54 conduction case body 55 conduction case cover 55F front case cover 55R rear case cover 58 air cleaner 58a cleaner case body 58b cleaner case cover 60 breather hole

Claims (3)

[Claims] 1. A power unit integrally comprising an engine and a conductive case for transmitting the output of the engine to a rear wheel, wherein the conductive case comprises a conductive case body and a conductive case cover which are separably combined. An air cleaner configured by dividing a cleaner case body and a cleaner case cover in a separable manner is provided on an upper portion of the conductive case, and the conductive case cover and the cleaner case body are integrally molded. Integrated power unit. 2. The conductive case cover is configured to be separable into front and rear, the front case cover is formed of a metal material, and the rear case cover is formed of a resin material integrally with the cleaner case body. Integrated power unit. 3. The inside of the crankcase of the engine and the inside of the conduction case are communicated with each other through a breather device, and a breather hole is formed at a portion where the inside of the cleaner case cover and the conduction case cover are in contact with each other, The integrated power unit according to claim 1, wherein the inside of the air cleaner and the inside of the conduction case are communicated with each other by the breather hole.