JP2002303132A - Motorcycle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motorcycle capable of improving the assemblability by reducing the number of components, stably supplying the secondary air, reducing the transmission noise such as mechanical noise, and effectively utilizing a space formed on an upper part of a cylinder head. SOLUTION: In this motorcycle having a car body frame 2 composed of a main frame 4 extended obliquely rear lower part and equipped with an engine 1, and a seat frame 6 equipped with a seat 20, and provided with a secondary air control mechanism part C for supplying the secondary air from an air cleaner box 19 at a rear side of the engine 1 and at a lower part of the seat 20 to an exhaust system b, and a secondary air supply device B composed of a check valve 33, the secondary air control mechanism part C and the check valve 33 are directly mounted on an upper part of a head cover 1d of a cylinder 1a formed by forwardly inclining a cylinder head 1c of the engine 1, and a secondary air passage 23 is provided along the car body frame 2 for supplying the secondary air from the air cleaner box 19 to the secondary air supply device B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a secondary air supply device for directly attaching a secondary air control mechanism for controlling an amount of secondary air supplied to an exhaust system of an engine and a check valve to a cylinder head cover. Related to motorcycles.

[0002]

2. Description of the Related Art Conventionally, as a motorcycle equipped with a secondary air supply device, for example, there is one described in Japanese Utility Model Laid-Open No. 53-97212. A secondary air supply device mounted on this conventional motorcycle is provided with a check valve that introduces secondary air to an exhaust system of an engine using exhaust pulsation, and is provided in series with the check valve, and A secondary air control mechanism that opens and closes a secondary air supply path according to the operation state of the engine is housed in a case, and is connected to an exhaust port of the engine via a secondary air hose. It is a configuration.

[0003]

However, in the above-mentioned conventional motorcycle, the secondary air supply device itself must be attached to the cylinder head, and the secondary air supply device is mounted on the air cleaner box. Since the secondary air supply device and the exhaust port of the engine must be connected by a secondary air hose, their assembly is complicated and the number of parts is large.

In addition, when noise such as mechanical noise is transmitted to the outside from a secondary air hose which forms a path from a secondary air supply device to an exhaust port, and when the rigidity of the secondary air hose is insufficient, an engine is required. There is a problem that the secondary air supply amount becomes unstable due to resonance with vibrations such as the above.

Accordingly, the present invention is to reduce the number of parts to improve the assemblability and maintainability, to reduce the cost, to stably supply the secondary air, and to reduce the transmission noise such as mechanical noise. Yes, and
It is an object of the present invention to provide a motorcycle that can effectively utilize a space formed above a cylinder head.

[0006]

In order to achieve the above object, the present invention has the following arrangement. That is, the present invention
The vehicle has a body frame including a main frame that extends diagonally downward from the steering head pipe and mounts an engine, and a seat frame that is connected to the main frame and mounts a seat thereon. A motorcycle equipped with a secondary air supply device including a secondary air control mechanism for supplying secondary air to an engine exhaust system from an air cleaner box disposed below a seat and a check valve is provided. The secondary air control mechanism and the check valve are directly attached to the upper part of the head cover of the cylinder in which the cylinder head is tilted forward in the vehicle traveling direction, and secondary air is supplied from the air cleaner box along the vehicle body frame. A secondary air passage for supplying secondary air to the apparatus is arranged and fixed.

In this configuration, the secondary air control mechanism and the check valve are mounted directly on the upper part of the cylinder head cover of the cylinder which is inclined forward in the vehicle traveling direction of the engine, so that the number of parts is reduced. And cost reduction as well as improved maintainability and
The supply of secondary air can be stably performed, transmission noise such as mechanical noise can be reduced, and the space above the cylinder head of the cylinder that is inclined forward in the vehicle traveling direction of the engine can be effectively used.

In the above, the air cleaner box is disposed below the seat provided on the seat frame, and the secondary air passage is formed so as to be lower from the front side to the rear side in the vehicle body traveling direction. By arranging and fixing along a part of the body frame, the secondary air passage can be stabilized.

In the above, the upstream opening of the secondary air passage is connected to the air cleaner box in a state where it is disposed at a position lower than the secondary air supply device, so that the air is returned into the air cleaner box. Even if the blow-by gas adheres in the secondary air passage, the oil component contained in the blow-by gas can be prevented from being sucked into the secondary air supply device together with the secondary air.

In the above, by making the secondary air cleaner box common to the air cleaner box for supplying fresh air to the engine air supply system, the arrangement of components, piping and the like can be performed extremely easily. As a result, the assembling work is reduced, and the size and cost of the device can be reduced.

[0011] In the above, the upstream opening of the secondary air passage is connected to the air cleaner box at a position lower than the upstream opening of the air supply passage forming the air supply system of the engine, so that the air cleaner box is provided. Even if the blow-by gas recirculated inside adheres to the secondary air passage, the oil component contained in the blow-by gas is prevented from being sucked into the secondary air supply device together with the secondary air. it can.

In the above, the secondary air cleaner box is formed as a separate air cleaner box independent of the air cleaner box for supplying fresh air to the engine air supply system, so that the negative pressure of the engine is reduced. Even when the air pressure rises, air enough to be supplied to the secondary air passage can be secured.

[0013]

Embodiments of the present invention will be described with reference to the drawings. 1 is a side view of a motorcycle according to a first embodiment of the present invention, FIG. 2A is an enlarged side view of the engine shown in FIG. 1, and FIG. 3A is a front view mainly showing the secondary air supply device, and FIG. 3B is a cross-sectional view taken along the line II-II shown in FIG.

A motorcycle A according to a first embodiment of the present invention has an air-cooled four-stroke engine 1 (hereinafter, simply referred to as an engine) mounted on a vehicle body frame 2, and substantially the entire vehicle body frame 2 is synthesized. Resin body cover 3
a, Covered by upper fairing 3b.

The vehicle body frame 2 is provided with a main frame 4 which is tilted so as to be lowered from the front side to the rear side in the vehicle body traveling direction α, and from the rear portion of the main frame 4 toward the rear side in the vehicle body traveling direction α. The rear frame 5, the main frame 4 and the rear frame 5 provided to be tilted so as to be higher.
The seat frames 6 are provided substantially horizontally between the intermediate portions of the above, and are connected by welding or the like as appropriate.

A front fork 8 is supported on a steering head pipe 7 connected to a front end of the main frame 4 so as to be steerable, and a front wheel 9 is pivotally supported at a lower end of the front fork 8. A steering handle 10 is connected to the upper end. In addition, 11 is a front fender.

A swing arm 13 centering on a pivot 12 is supported on the rear portion of the main frame 4 so as to be vertically swingable.
4 is supported. Reference numeral 15 denotes a rear fender attached to the rear frame 5.

The cylinder 1 is located below the main frame 4.
a is tilted forward in the vehicle body traveling direction α, and the engine 1 is mounted on a frame. In the rear of the engine 1, in other words, in the middle of the main frame 4, an air supply port of the cylinder head 1 c is provided. A carburetor 17 connected via a suction pipe 16 to 1b is provided.

The carburetor 17 is connected via an inlet tube 18 to an air cleaner box 19 arranged below the front end of the seat frame 6.
A long seat 20 is fixed to the front and back of the seat frame 6, and the battery 21 and the fuel tank 22 are positioned below the seat 20 and above the seat frame 6. The suction pipe 16, the carburetor 17, and the inlet tube 18 constitute an air supply system a.

As shown in FIG. 2, the air cleaner box 19 is formed in a vertically long trapezoidal shape in a side view, and a tube connection tube 19b for connecting the inlet tube 18 is provided on the front upper slope 19a. And a front side surface 19c below the tube connecting tube 19b.
A hose connection pipe 19d for connecting an air inlet 23a, which is an opening on the upstream side of an air hose 23, which is a secondary air passage described later, is provided.

An exhaust pipe 24 is connected to a cylinder head 1c of the cylinder 1a. The exhaust pipe 24 is disposed on the right side of the engine 1 and performs a secondary combustion to purify exhaust gas. The exhaust pipe 24 and the muffler 25 form an exhaust system b.

In the present embodiment, a position deviated to one side (right side) of the cylinder head cover 1d (hereinafter, simply referred to as a head cover) of the cylinder 1a, that is, a position shifted from a cam chain disposition position. The secondary air supply device B is directly attached to the position.

That is, by tilting the cylinder 1a forward, the space efficiency is improved by disposing the secondary air supply device B in the space γ formed between the head cover 1d and the main frame 4. . In addition, by disposing the secondary air supply device B at a position different from the cam chain disposition position on the upper surface of the head cover 1d, the axial dimension of the cylinder 1a can be reduced. Further, in the present embodiment, since the cam chain is disposed on one side (left side) of the cylinder 1a, the secondary air supply device B passes through the axis О of the cylinder 1a and is located on the side in the vehicle width direction β. Since it is arranged at a deviated position, the operability from the other side (right side) can be enhanced, and therefore, maintenance work and the like can be easily performed.

The secondary air supply device B includes the muffler 25
And the like to promote the secondary combustion performed in the above-described manner, and the configuration thereof is as follows. As shown in FIGS. 3A and 3B, reference numeral 26 denotes a main body formed in a substantially elliptical cylindrical shape.
A ring-shaped recess 26b centered on the axis P is formed on one end surface 26a, and a stepped recess 26d having two large and small inner diameters is formed on the other end surface 26c. A shaft hole 26e communicating the two end surfaces 26a, 26c is formed so as to coincide with the axis P.

On the one end surface 26a of the main body 26, a flange 27a having a diameter substantially corresponding to the outer diameter of the main body 26 is formed on the entire periphery of the opening, and a shallow bottom for forming a diaphragm chamber δ having a required volume. A cylindrical cap 27 is provided, and a control pipe 27b projects from the center of the cap 27.

In the diaphragm chamber δ, the main body 26
A diaphragm 28 having an outer diameter substantially matching the outer diameter of the one end surface 26a and having a circular shape formed of a thin film having elasticity such as rubber has an outer edge portion formed by the flange portion 27a of the cap 27 and the main body portion 26. It is housed in a state of being sandwiched between the end face 26a.

The other end surface 26c of the main body 26 is fitted into the opening 26f of the stepped concave portion 26d to form the valve chamber ε.
Is formed, and a shallow-bottom cylindrical cap 29 is provided, and an inflow pipe 29a protrudes from the center of the cap.

A valve 31 fixed to the other end of the shaft 30 slidably fitted in the shaft hole 26e is disposed in the large diameter portion 26d 'of the stepped concave portion 26d.
A coil spring 32 for positioning the valve 31 at a position separated from the stepped recess 26d and the inner opening 29a 'of the inflow pipe 29a is disposed.

A reed valve main body 26h is sandwiched between the main body 26 and the head cover 1d, and a through-hole 26g for communicating the mounting recess 1e with the valve chamber ε is formed. A check valve 33 for opening and closing the through hole 26g is attached to the reed valve body 26h.

The mounting recess 1e has a fitting step 1 having an inner diameter fitted to the reed valve main body 26h on the upper surface opening side.
f has a check flow preventing valve disposing recess 1g having a volume that does not hinder the elastic deformation of the check flow preventing valve 33 below this.

The check valve 33 allows air to flow from the main body 26 to the mounting recess 1e of the head cover 1d, and prevents air from flowing into the main body 26 from the mounting recess 1e. Is what it is.
In the present embodiment, the diaphragm 28, the shaft 3
The secondary air control mechanism C is constituted by the 0, the valve 31, and the coil spring 32.

The inflow pipe 29a is connected to the air cleaner box 1 via an air hose 23 as a secondary air passage.
9, the air cleaner box 1 of the total length of the air hose 23 as shown in FIGS.
Most of the length 2 from 9 to the side of the head cover 1d
3b is fixed in a straight line along the main frame 4. That is, by fixing the flexible air hose 23 to the main frame 4 which is a rigid body, the air hose 23 is prevented from vibrating in response to the vibration of the engine or the like. Since the pipeline resistance can be reduced, the supply of the secondary air can be performed more smoothly.

The control pipe 27b is connected to an air supply system such as the carburetor 17 or the suction pipe 16 on which a suction negative pressure acts via an air hose (not shown).
In the present embodiment, the air cleaner box 1
9, by the air hose 23 and the secondary air supply device B,
A next air supply system c is configured.

Incidentally, the positional relationship between the secondary air supply device B and the air cleaner box 19 is, in the present embodiment, as shown in FIGS. Is disposed at a position higher than the hose connection pipe 19d of the air cleaner box 19 for connecting the hose.

That is, even if the blow-by gas recirculated into the air cleaner box 19 adheres to the inside of the air hose 23 which is a secondary air passage, the secondary air supply device B removes the air hose 23 from the air hose 23. Since it is disposed at a position higher than the hose connection pipe 19d of the air cleaner box 19 for connection, the oil component in the air hose 23 can be returned to the air cleaner box 19, so that it is included in the blow-by gas. 2 oil components
It can be prevented from being sucked into the secondary air supply device B together with the next air.

In the present embodiment, the inlet tube 18 connected to the upper slope of the air cleaner box 19 is disposed above the air hose 23 for the secondary air passage. Therefore, the air cleaner box 1
9, a blow-by gas is recirculated separately, and the air cleaner box 1
9, there is a possibility that the oil component may be supplied. However, the inlet tube 18 has an upper slope 19a.
It is designed to be opened to prevent suction of oil components. Then, the air hose 23 that may suck the oil component can return the oil component adhered in the air hose 23 to the inside of the air cleaner box 19 as described above, so that there is no adverse effect.

The flow of air in the air supply system a and the secondary air supply system c is as follows. <Air supply system> The air introduced from the air cleaner box 19 is supplied to the carburetor 17 via the inlet tube 18 after removing dust and the like contained therein. Here, the carburetor 17 mixes fuel and air supplied from the fuel tank 22, supplies the mixture into the cylinder head 1c of the engine 1 to drive the engine 1, and its driving force is a power not shown. The power is transmitted to the rear wheels 14 via the transmission mechanism and is converted into rotational force.

<Secondary Air Supply System> On the other hand, the air filtered by the air cleaner box 19 is supplied to the engine 1
When the throttle valve is driven, it always flows into the secondary air supply device B, but when the throttle valve is rapidly closed, the flow into the secondary air supply device B is prevented.

That is, the air filtered by the air cleaner box 19 is supplied as secondary air from the secondary air supply device B directly to the exhaust system b when the valve 31 is open. Thereby, the secondary combustion in the muffler 25 connected to the exhaust pipe 24 is promoted, and the action of purifying the exhaust gas is improved. That is, since there is no need to provide an air hose between the secondary air supply device B and the head cover 1d as in the related art, transmission of mechanical noise or the like does not occur, and noise can be reduced accordingly.

The secondary air supply device B is connected to a carburetor 17 (or an air supply system such as a suction pipe 16 on which a suction negative pressure acts) by an air hose (not shown) connected to the control pipe 27b. Therefore, when the pressure in the chamber of the carburetor 17 (or the air supply system on which the suction negative pressure acts on the suction pipe 16 or the like) becomes negative by the driving of the engine 1, the secondary air supply device B
Of the diaphragm chamber δ becomes negative pressure,
Is located outside the diaphragm chamber δ (one end surface 26a of the main body 26).
, And the valve 31 moves together with the shaft 30 against the elastic pressure of the coil spring 32,
The valve 31 comes into close contact with the stepped recess 26d, and the supply of the secondary air to the exhaust system b is temporarily stopped. At this time, even if the exhaust gas becomes a positive pressure and the pressure in the check valve arranging recess 1g rises, the check valve 33 only comes into close contact with the reed valve body 26h, so that the exhaust gas can be prevented from flowing back.

In this embodiment, since the air cleaner box for supplying the secondary air and the air cleaner box for supplying the air to the carburetor 17 are also used, the arrangement of the components, the piping, etc. Can be performed very easily, the assembling work is reduced, and the size and cost of the device can be reduced. However, the secondary air supply air cleaner box may be a separate type that is independent of the air cleaner box that supplies fresh air to the carburetor 17. In this case, it is needless to say that it has the same function as described above and also has the same effect. Further, when the negative pressure of the engine 1 increases and inertia supercharging starts to occur, when the air cleaner box is used as a common product, air for secondary air is sucked into the carburetor 17 as fresh air for air supply. On the other hand, by using a separate air cleaner box, air for secondary air can be secured. In the present embodiment, the reed valve main body 26h
Has been described between the main body 26 and the head cover 1d. However, the reed valve main body 26h, the check valve 33 and the check valve guide 26i are formed integrally with the main body 26, and the reed valve body 26h is formed above the head cover 1d. It may be attached directly.

Next, a motorcycle according to a second embodiment will be described with reference to FIG. This motorcycle A '
Is a so-called off-road type in which an air-cooled four-cycle engine 34 is mounted on a body frame 35.

The body frame 35 is provided with an upper frame 3 which is tilted so as to be lower from the front side to the rear side.
6, a main frame 37 which is provided to be inclined so as to gradually lower from a rear portion of the upper frame 36 toward the rear side of the vehicle body traveling direction α, a front end portion of the upper frame 36 and a lower portion of the main frame 37. A substantially J-shaped down frame 38 disposed therebetween, a seat frame 39 formed so as to be gradually higher from the rear portion of the upper frame 36 toward the rear side, and between the seat frame 39 and the main frame 37. The rear pipe 40 is tilted and provided, and these are connected appropriately by welding or the like.

The upper frame 36 and the down frame 3
8 steering head pipe 41 connected to the front end
A front fork 42 is supported so as to be steerable, and a front wheel 4 is attached to a lower end of the front fork 42.
3, and a steering handle 44 is connected to the upper end. In addition, 45 is a front fender.

A swing arm 47 centering on a pivot 46 is vertically swingably supported by the lower part of the main frame 37, and a rear wheel 48 is supported by the swing arm 47.

On the front side of the main frame 37, the engine 34 having a cylinder 34a in which a cylinder head 34c is inclined toward the front side in the vehicle body traveling direction α is mounted and mounted. In other words,
Near the upper end of the main frame 37, the cylinder head 3
A carburetor 50 connected to the air supply port 34b of 4c via a suction pipe 49 is provided.

The carburetor 50 is connected via an inlet tube 51 to an air cleaner box 52 disposed below the front side of the seat frame 39.
In addition, a long seat 53 is provided on the seat frame 39.
Is fixed, and at the front side of the sheet 53,
The fuel tank 54 is mounted on the main frame 37.

The air cleaner box 52 is formed in a vertically long trapezoidal shape in a side view, and an inlet tube 51 is connected to the front side surface 52a.
2a, an air inlet 5 which is an opening on the upstream side of an air hose 55 which is a secondary air passage below the inlet tube 51.
5a is provided.

An exhaust pipe 56 is connected to the cylinder head 34c of the cylinder 34a.
A muffler 57 disposed on the right side of the seat frame 39 and containing a catalyst for performing an oxidation reaction for purifying exhaust gas is connected.

The head cover 34d of the cylinder 34a
In the present embodiment, a secondary air supply device B 'similar to the above is provided at a position deviated to one side (right side), that is, a position shifted from the cam chain disposition position. Is directly attached.

That is, by tilting the cylinder 34a forward, the head cover 34d and the upper frame 36
By arranging the secondary air supply device B 'in the space γ' formed between them in the same manner as in the first embodiment, the space efficiency can be improved. In addition, by disposing the secondary air supply device B 'on the upper surface of the head cover 34d at a position different from the position where the cam chain is disposed, the axial dimension of the cylinder 34a can be reduced. Further, in this embodiment, since the cam chain is disposed on one side (left side) of the cylinder 34a, the secondary air supply device B 'passes through the axis О of the cylinder 34a and is located on the side in the vehicle width direction β. , The operability from the other side (right side) can be enhanced, and therefore maintenance work and the like can be easily performed.

The air cleaner box 52 is connected to the secondary air supply device B 'via an air hose 55 as a secondary air passage.
Of the required length 55b in the middle of the
The pipe is fixed linearly along the main frame 37.

That is, by fixing the flexible air hose 55 to the main frame 37 which is a rigid body, the air hose 55 is prevented from vibrating in response to the vibration of the engine 34 and the like. Since the pipe resistance can be reduced by piping, supply of secondary air can be performed more smoothly.

In the present embodiment, the positional relationship between the secondary air supply device B 'and the air cleaner box 52 is such that the secondary air supply device B' is located at a position higher than the connection position of the air hose 55 and the air cleaner box 52. It is arranged to be high.

That is, even if the blow-by gas recirculated in the air cleaner box 52 may adhere to the air hose 55 which is a secondary air passage, the secondary air supply device B 'is The oil component contained in the blow-by gas flows down in the air hose 55 and returns to the air cleaner box 52 because the oil component is disposed higher than the connection position of the air cleaner box 52 with the secondary air. This prevents the oil component from being sucked into the secondary air supply device B '. However, the secondary air supply air cleaner box may be a separate type independent of the air cleaner box that supplies fresh air to the carburetor 50. In this case, it is needless to say that it has the same functions as those described above and also has the same effects. Further, when the negative pressure of the engine 34 increases and inertia supercharging starts to occur, when the air cleaner box is used as a common product, air for secondary air is sucked into the carburetor 50 as fresh air for air supply. On the other hand, by using a separate air cleaner box, air for secondary air can be secured. In this embodiment,
Similar to the above, the reed valve main body is sandwiched between the main body and the head cover, but the reed valve main body, the check valve and the check valve are formed integrally with the main body,
This may be directly attached to the upper part of the head cover.

A motorcycle according to a third embodiment will be described with reference to FIG. The motorcycle A ″ according to the present embodiment is a two-seater scooter on which a so-called unit swing engine 58 is mounted, and a whole body frame 59 is covered with a body cover 60 made of synthetic resin.

The vehicle body frame 59 has an upper frame 61 whose front half is formed substantially horizontally and whose rear half is gradually bent upward, and an upright portion 62a at the front side and middle of the upper frame 61. , 62b
A lower frame 62 having a substantially L-shaped side surface formed by standing up;
An auxiliary frame 63 is formed on the front upper portion of the upper frame 61 at the rear of the upright portion 62a on the front side of the lower frame 62, and these are connected by welding or the like as appropriate.

The vehicle body cover 60 has a leg shield 60a, a screen 60b and the like protruding to the left and right sides arranged on the front side, and a backrest 6 on the rear side thereof.
0c, etc., and a double seat 60d containing a fuel tank (not shown) is held at a lower portion. During the period from the front side of the vehicle body to the double seat 60d, an occupant riding the double seat 60d puts both feet. A pair of left and right plate-like footboards 60e, 60e (one of which is not shown), and a protruding portion 60f provided between the pair of footboards 60e, 60e.
g is formed, and a rear cover 60h is provided on the rear side of the floor portion 60g.

A front fork (not shown) is steerably supported on a steering head pipe 64 connected to the upright portion 62a of the lower frame 62 and the upper end of the auxiliary frame 63, and is connected to the lower end of the front fork. A front wheel 65 is pivotally supported, and a steering handle 66 is connected to the upper end.

An engine 58a and a power transmission 58b for transmitting the driving force of the engine 58a to the rear wheel 67 are integrally held at the connection between the intermediate portion of the upper frame 61 and the rear portion of the lower frame 62. The above-mentioned unit swing engine 5
8 is mounted so as to be able to swing up and down around a bracket 68 as a swing center.

The unit swing engine 58 connects the cylinder head 58f of the engine portion 58a to the body frame 59.
Is a water-cooled single-cylinder four-cycle type cylinder in which the cylinder 58c is tilted substantially horizontally toward the front of the vehicle. The rear wheel 67 is axially supported at the rear of the power transmission portion 58b, and its power transmission is performed. A rear shock unit 69 is provided between a rear portion of the portion 58b and a rear portion of the upper frame 61.

The unit swing engine 58 is formed integrally with a crankcase 58d that houses a crankshaft (not shown) and the like, and extends rearward of the crankcase 58d and applies the rotational force of the crankshaft to the rear wheel 67.
Case 58e having a built-in power transmission mechanism (not shown) for transmitting power to the cylinder 58c and a cylinder 58c and a cylinder head 5 that are tilted and protruded from the front end of the crankcase 58d.
The outer shell is constituted by 8f. In addition, 58 g
Is a head cover for closing the front end of the cylinder head 58f.

In the present embodiment, at the upper part of the cylinder head 58f, at a position deviated to one side (right side), that is, at a position shifted from the cam chain arrangement position, the same as the above-described one. A secondary air supply device B ″ is directly attached, and a carburetor 70 is disposed on the other side (left side).

The carburetor 70 includes a cylinder head 58
f is connected to an air supply port via an intake pipe (both not shown), and an air cleaner case 72 is connected via an inlet tube 71. The carburetor 70 is also connected to the fuel tank (not shown).

The air cleaner box 72 is arranged along the upper surface side of the swing case 58e, and therefore, at the rear side of the engine portion 58a, and swings up and down integrally with the swing case 58e. ing.

In the cylinder head 58f, an exhaust pipe 73 for guiding exhaust gas exhausted from the exhaust port extends under the crankcase 58d and extends to the right side of the rear wheel 67. A muffler 74 arranged on the right side of the rear wheel 67 is connected to the tube 73.

The secondary air supply device B ″ is connected to the air cleaner box 72 via an air hose 75 serving as a secondary air passage, and substantially the entire length of the air hose 75 extends along the upper frame 61. The pipe is fixed linearly.

That is, by fixing the flexible air hose 75 to the upper frame 61 which is a rigid body, the air hose 75 is prevented from vibrating in response to the vibration of the engine portion 58a or the like. Since the pipe resistance can be reduced by arranging the pipe, the supply of the secondary air can be performed more smoothly.

The positional relationship between the secondary air supply device B ″ and the air cleaner box 72 is similar to that of the above-described embodiments, and the secondary air supply device B ″ is an air cleaner for connecting the air hose 75. The box 72 is disposed at a position higher than the hose connection pipe 72a.

That is, even if the blow-by gas recirculated into the air cleaner box 72 may adhere to the air hose 75 serving as a secondary air passage, the secondary air supply device B ″ is connected to the air hose 75. The oil component contained in the blow-by gas is sucked into the secondary air supply device B ″ together with the secondary air because the oil component is disposed at a position higher than the hose connection pipe 72a of the air cleaner box 72 for connecting the air cleaner box 72. It is preventing. However, the secondary air supply air cleaner box may be a separate type that is independent of the air cleaner box that supplies fresh air to the carburetor 70. In this case, it is needless to say that it has the same functions as those described above and also has the same effects. Further, when the negative pressure of the engine 58 increases and inertia supercharging starts to occur, when the air cleaner box is used as a common product,
The air for secondary air is used as fresh air for air supply and the carburetor 70
By using a separate air cleaner box, air for secondary air can be secured. In this embodiment, the reed valve main body is sandwiched between the main body and the head cover, as described above, but the reed valve main body, the check valve, and the check valve guide are connected to each other. It may be formed integrally with the main body, and may be directly attached to the upper part of the head cover 58g.

[0071]

According to the first to sixth aspects of the present invention, the secondary air control mechanism and the check valve are integrally formed (or the secondary air control mechanism and the check valve are separately provided). )
The secondary air supply unit is mounted directly on the top of the cylinder head cover where the cylinder head is tilted toward the front of the engine in the vehicle traveling direction. This reduces the number of parts, improves assembly and maintenance, and reduces costs. , The supply of secondary air can be performed stably, transmission noise such as mechanical noise can be reduced, and the cylinder head is tilted forward in the vehicle body traveling direction. Space can be used effectively. In addition, since the air cleaner box is arranged below the seat frame of the vehicle body frame, it is possible to reduce dust and the like adhering to the air cleaner box and being sucked.

In addition to the common effects obtained by the first to sixth aspects of the present invention, the following effects can be obtained by the inventions of the respective aspects. According to the second aspect of the present invention, the air cleaner box is arranged below the seat provided on the seat frame, and the secondary air passage is lowered from the front side to the rear side in the vehicle body traveling direction. By arranging and fixing along a part of the formed body frame,
The secondary air passage can be stabilized, and thus the secondary air can be supplied stably.

According to the third aspect of the present invention, the air cleaner is connected to the air cleaner box while the upstream opening of the secondary air passage is disposed at a position lower than the secondary air supply device. Even if the blow-by gas recirculated in the box adheres to the secondary air passage, the oil component contained in the blow-by gas flows down in the air hose 55 and returns to the air cleaner box. It is possible to prevent the oil component from being sucked into the secondary air supply device together with the air.

According to the fourth aspect of the present invention, the secondary air cleaner box is shared with the air cleaner box connected to the air supply system of the engine, so that the air cleaner box can be freely mounted on the vehicle body. More often.

According to the fifth aspect of the invention, the upstream opening of the secondary air passage is connected to the air cleaner box at a position lower than the upstream opening of the air supply passage forming the air supply system of the engine. The blow-by gas recirculated into the air cleaner box can be prevented from being sucked into the air supply passage, and even if the blow-by gas is sucked into the secondary air passage, the blow-by gas is included in the blow-by gas It is possible to prevent the oil component from being sucked into the secondary air supply device together with the secondary air.

According to the sixth aspect of the present invention, the secondary air cleaner box is a separate type air cleaner box independent of the air cleaner box connected to the engine air supply system, so that the negative pressure of the engine is reduced. Is high, air enough to be supplied to the secondary air passage can be secured.

[Brief description of the drawings]

FIG. 1 is a side view of a motorcycle according to a first embodiment of the present invention.

2 (A) is an enlarged side view of the engine shown in FIG. 1 as viewed from the opposite side, and FIG. 2 (B) is an arrow view from the direction I shown in FIG. 2 (A).

FIG. 3A is a front view mainly showing a secondary air supply device, and FIG. 3B is a cross-sectional view taken along line II-II shown in FIG.

FIG. 4 is a side view of a motorcycle according to a second embodiment of the present invention.

FIG. 5 is a side view of a motorcycle according to a third embodiment of the present invention.

[Explanation of symbols]

 1,34,58 Engine 1a, 34a, 58c Cylinder 1d, 34d, 58g Head cover 1f, 34c, 58f Cylinder head 2,35,59 Body frame 4,37 Main frame 6,39 Seat frame 7,41,64 Steering head pipe 19, 52, 72 Air cleaner box 20 Seat 23, 55, 75 Air hose as secondary air passage 33 Check valve B, B ', B "Secondary air supply device C Secondary air control mechanism b Engine exhaust system

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F01N 3/34 F01N 3/34 B H 7/08 7/08 G F term (Reference) 3D038 BA01 BA12 BA15 BB00 BC08 BC15 3G004 AA02 BA09 DA22 DA24 3G091 AA03 AA28 BA39 CA22 HB07

Claims (6)

[Claims] 1. A main frame which extends diagonally rearward from a steering head pipe and mounts an engine,
A motorcycle having a body frame composed of a seat frame connected to the main frame and mounting a seat, wherein secondary air is supplied to an engine exhaust system from an air cleaner box disposed behind the engine and below the seat. In a motorcycle equipped with a secondary air supply device comprising a secondary air control mechanism for supplying air and a check valve, the cylinder head of the engine is tilted forward in the vehicle body traveling direction. 2 above
A secondary air passage for feeding secondary air from the air cleaner box to the secondary air supply device along the vehicle body frame by directly attaching the secondary air control mechanism and the check valve is provided. Motorcycle characterized by: 2. An air cleaner box is disposed below a seat provided on a seat frame of a vehicle body frame, and the secondary air passage is formed so as to be lower from a front side to a rear side in a vehicle body traveling direction. The motorcycle according to claim 1, wherein the motorcycle is disposed and fixed along a part of the body frame. 3. The motorcycle according to claim 1, wherein the upstream opening of the secondary air passage is connected to the air cleaner box in a state of being disposed at a position lower than the secondary air supply device. 4. The motorcycle according to claim 1, wherein said secondary air cleaner box is common to an air cleaner box for supplying fresh air to an engine air supply system. 5. The motorcycle according to claim 4, wherein the upstream opening of the secondary air passage is connected to the air cleaner box at a position lower than the upstream opening of the air supply passage forming the air supply system of the engine. . 6. The air cleaner box according to claim 1, wherein said secondary air cleaner box is a separate air cleaner box independent of an air cleaner box for supplying fresh air to an engine air supply system. Or the motorcycle according to 3.