JP4648132B2 - Vaporizer arrangement structure in small vehicles - Google Patents

Description

The present invention includes a backbone-type body frame that includes a head pipe that supports the front fork so that the front fork can be steered, and a single main frame that is connected to the head pipe and disposed on the center line of the vehicle body in plan view. The single main frame has a rearwardly inclined gentle slope part extending rearward from the head pipe, and a rearwardly inclined steep slope part extending downward from the rear end of the gentle slope part, The body frame is mounted with an engine body disposed below the gentle slope portion and ahead of the steep slope portion, and a carburetor included in an intake system connected to a cylinder head of the engine body is disposed on the engine body side. An intake passage having an intake axis inclined so as to be closer to the vehicle body center line toward the vehicle body, and a throttle valve for controlling the amount of intake air flowing through the intake passage Wherein an improvement of the vaporizer arranged structure definitive a small-type vehicle that will be placed on the side of the main frame.

For example, Patent Document 1 discloses a motorcycle in which a carburetor that constitutes a part of an intake system is disposed on the side of a main frame that is a part of a body frame that is a backbone type.
Japanese Utility Model Publication No. 2-118157

  By the way, the carburetor avoids interference with the main frame, and is disposed on the side of the main frame. Since the main frame is on the vehicle body center line, the intake axis of the intake passage provided in the carburetor is The vehicle body must be inclined so as to be closer to the center line of the vehicle body as it goes toward the engine body side. In the one disclosed in Patent Document 1, the rear part of the main frame has a left and right divided structure, and the vehicle body frame and the rear cushion. Since the intake axis is passed between them, the inclination angle of the carburetor's intake axis with respect to the center line of the vehicle body becomes relatively large, and the intake passage must be greatly bent between the carburetor and the cylinder head. The frame structure becomes complicated and the intake resistance becomes relatively large.

  The present invention has been made in view of such circumstances, and can reduce the intake resistance between the carburetor and the cylinder head without complicating the frame structure, thereby improving engine performance and reducing fuel consumption. An object of the present invention is to provide a carburetor arrangement structure in a small vehicle.

In order to achieve the above-mentioned object, the invention of claim 1 is characterized in that a backbone-type vehicle body frame has a head pipe that supports the front fork so that the front fork can be steered, and a straight line on the vehicle body center line in a plan view of the vehicle connected to the head pipe. A single main frame extending rearwardly from the head pipe , the single main frame extending rearwardly from the head pipe, and a rearwardly inclined portion extending downward from a rear end of the gently inclined portion. The vehicle body frame is mounted with an engine body disposed below the gentle slope portion and in front of the steep slope portion, and is connected to a cylinder head of the engine body. carburetor included in the system is, and the steep portion is inclined and the side view of the vehicle such that the vehicle body center line closer toward the engine body side plan view of the vehicle An intake passage having an insert intake axis, a carburetor arrangement structure in a small vehicle which is disposed on the side of the steep portion and a throttle valve for controlling the amount of intake air flowing through the intake passage When viewed from the side of the vehicle, the intake axis of the intake passage passes through the valve shaft of the throttle valve, and a throttle sensor is coaxially connected to one end of the valve shaft on the steeply inclined portion side, and a throttle drum is coaxially connected to the other end. mounted on the steep portion, on the side facing the carburetor, the carburetor to have recesses that allows to close to the vehicle body center line side is formed, one of the throttle sensor in the recess part is it said that you have entered.

According to the present invention, since the carburetor can be arranged closer to the vehicle body center line side, the inclination angle of the carburetor intake axis with respect to the vehicle body center line can be relatively reduced without complicating the structure of the vehicle body frame. It can be set small, it is not necessary to bend the intake passage between the carburetor and the cylinder head greatly, and the intake resistance from the carburetor to the cylinder head is kept small, improving the engine performance and The fuel consumption can be reduced.

Also it is possible to close the carburetor to the vehicle body center line side while simplifying the structure of the vaporizer and coaxially on both ends of the valve shaft of the throttling valve so that the throttle drum and the throttle sensor is mounted.

The throttle sensor is more conductive instrumentation products can be protected by the main frame.

  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 one embodiment of the present invention, FIG. 1 is a side view of a motorcycle, FIG. 2 is an enlarged view of a main part of FIG. 1, and FIG. 3 is a sectional view taken along line 3-3 of FIG. 4 is a view taken in the direction of arrow 4 in FIG. 3, and FIG. 5 is a longitudinal side view of the vaporizer.

  First, in FIG. 1, a body frame F of a motorcycle, which is a small vehicle, is tilted slightly downward and rearward from a head pipe 12 that supports a front fork 11 that pivotally supports a front wheel WF and a head pipe 12 that can be steered. A single main frame 13 having a gentle slope portion 13a and a steep slope portion 13b extending downward from the rear end of the slow slope portion 13a, and a pivot plate provided at the rear end portion of the steep slope portion 13b of the main frame 13 14 and a pair of left and right seat rails 15 that extend rearward with the front end joined to the main frame 13 at the connecting portion of the gently inclined portion 13a and the steeply inclined portion 13b, and more than the front end connecting portion of the main frame 13. A single down frame 16 having a front end joined to the head pipe 12 below and extending downward, and the main frame 13 includes a sub-pipe 17 that connects between the gently inclined portion 13a and the down frame 16, and a pair of left and right reinforcing frames 18 that connect between the pivot plate 14 and the two seat rails 15. .

  Referring also to FIG. 2, an engine body 21 of a single cylinder engine includes a crankcase 23, a cylinder body 24, a cylinder head 25, and a head cover 26 that support a crankshaft 22 having an axis line arranged in the width direction of the motorcycle. Are arranged in a space surrounded by the main frame 13, the pivot plate 14, and the down frame 16 in the body frame F. In addition, the upper and lower portions of the crankcase 23 are supported by the support bracket 27 attached to the lower end portion of the down frame 16, and the rear upper and lower portions of the crankcase 23 are supported by the pivot plate 14.

  A transmission (not shown) for shifting the rotational power of the crankshaft 22 is accommodated in the crankcase 23, and one end of the output shaft 28 of the transmission is located behind the crankshaft 22. It protrudes outward from the crankcase 23. Moreover, an endless chain 31 is wound around a driving sprocket 29 fixed to the protruding end of the output shaft 28 and a driven sprocket 30 provided on the rear wheel WR.

  The rear wheel WR is rotatably supported at the rear end portion of the swing arm 32, and the front end portion of the swing arm 32 is around the axis of the connecting shaft 33 that connects the reinforcing frame 18 to the pivot plate 14. It is supported by the pivot plate 14 so that it can swing. Further, a rear cushion unit 34 is provided between a portion where the reinforcing frames 18 are connected to the seat rails 15 and a rear portion of the swing arm 32.

  An upstream end of an exhaust pipe 35 is connected to the front side wall of the cylinder head 25, and the exhaust pipe 35 extends from the front of the engine body 21 to the lower side of the crankcase 23 and extends rearward. A downstream end of the exhaust pipe 35 is connected to an exhaust muffler 36 disposed on the right side of the WR.

  Referring also to FIG. 3, an intake system 37 is connected to the rear side wall of the cylinder head 25 provided in the engine main body 21 disposed at the rear of the main frame 13, that is, in front of the steeply inclined portion 13 b. The intake system 37 includes an intake pipe 38 whose downstream end is connected to the rear side wall of the cylinder head 25, a carburetor 39 disposed at the rear of the intake pipe 38, and a large portion behind the steeply inclined portion 13b. And an air cleaner 40 disposed further rearward of the carburetor 39. The upstream end of the intake pipe 38 and the downstream end of the carburetor 39 are connected by a connection pipe 41 such as a hose, and the air cleaner 40 is provided. The outlet pipe 40a and the upstream end of the vaporizer 39 are connected by a connecting pipe 42 such as a hose.

  By the way, the main frame 13 in the vehicle body frame F is formed by bending a metal tube so that the axis line is disposed on the vehicle body center line C, and the carburetor 39 has a steeply inclined portion in the main frame 13. It is arranged on the right side of the upper part of 13b.

  With further reference to FIG. 4, it is possible to bring the carburetor 39 closer to the vehicle body center line C side on the side surface facing the carburetor 39 in the upper portion of the steeply inclined portion 13 b of the main frame 13. The depressed portion 44 is formed by drawing a part of the main frame 13.

  In FIG. 5, the vaporizer body 45 of the vaporizer 39 integrally has an upper diaphragm chamber portion 45 a and a lower flange 45 b, and forms a float chamber 46 between the vaporizer body 45 and the vaporizer body 45. 47 is fastened to the lower surface of the flange 45b. An intake passage 48 passes through the center of the carburetor main body 45, and a main nozzle 49 that opens to the bottom surface of the intake passage 48 and an intake flow direction 64 indicated by an arrow on the downstream side of the main nozzle 49. A plurality of slow nozzles 50 that open to the bottom surface of the intake passage 48 are provided in the carburetor main body 45. Thus, the main nozzle 49 and the slow nozzle 50 communicate with the main jet 51 and the slow jet 52 that open below the fuel oil level in the float chamber 46.

  The piston valve 53 disposed immediately above the main nozzle 49 is slidably fitted into a guide hole 54 provided in the carburetor body 45, and an inner peripheral bead portion is formed at the upper end of the piston valve 53. The peripheral edge portion of the diaphragm 55 to be fixed is sandwiched between the diaphragm chamber portion 45a of the vaporizer body 45 and the lid member 56 fastened to the diaphragm chamber portion 45a. The space between the diaphragm chamber portion 45a and the lid member 56 is partitioned by the diaphragm 55 into a venturi negative pressure chamber 57 on the lid member 56 side and an atmospheric pressure chamber 58 on the diaphragm chamber portion 45a side. The atmospheric pressure chamber 58 communicates with the air through the air inlet hole 60 opened at the upstream end face of the carburetor body 45, and communicates with the intake passage 48 through the negative pressure introduction holes 59. Communicate.

  The piston valve 53 is urged in the downward direction by a return spring 61 accommodated in the venturi negative pressure chamber 57, and a primary venturi 62 is formed in the intake passage 48 at the lower limit of the piston valve 53. A needle valve 63 inserted into the main nozzle 49 is held at the lower end of the piston valve 53.

  A butterfly throttle valve 65 that controls the amount of intake air flowing through the intake passage 48 is disposed in the vicinity of the slow nozzles 50 downstream of the piston valve 53. A valve shaft 66 of the throttle valve 65 is rotatably supported by the carburetor body 45, and a throttle drum 67 and a throttle sensor 68 are coaxially attached to both ends of the valve shaft 66 protruding from the carburetor body 45. It is done.

  In FIG. 3 again, the carburetor 39 is inclined so that the intake axis IC of the intake passage 48 is closer to the vehicle body center line C as it goes toward the engine body 21, and the upper portion of the steeply inclined portion 13 b in the main frame 13. It is arranged on the right side. In addition, one of a throttle drum 67 and a throttle sensor 68 that are coaxially attached to both ends of the valve shaft 66 of the throttle valve 65 is disposed on the main frame 13 side. In this embodiment, the throttle sensor 68 is a part of the throttle sensor 68. The portion is disposed on the main frame 13 side so as to enter the recess 44.

Next, the operation of this embodiment will be described. The backbone type vehicle body frame F having the main frame 13 extending rearward from the head pipe 12 on the vehicle body center line C is more than the steeply inclined portion 13b which is the rear portion of the main frame 13. The engine main body 21 disposed in the front is mounted, and the intake passage 48 having the intake axis IC inclined so as to be closer to the vehicle body center line C toward the engine main body 21 side, and the amount of intake air flowing through the intake passage 48 are controlled. The carburetor 39 having the throttle valve 65 is disposed on the side of the main frame 13. The carburetor 39 is mounted on the side of the main frame 13 (particularly the steeply inclined portion 13 b) facing the carburetor 39. A recess 44 is formed that can be brought close to the center line C side.

  Therefore, since the carburetor 39 can be disposed closer to the vehicle body center line C while avoiding interference with the main frame 13, the intake axis IC of the carburetor 39 can be obtained without complicating the structure of the vehicle body frame F. Can be set to a relatively small inclination angle with respect to the vehicle body center line C, and the intake passage between the carburetor 39 and the cylinder head 25 is not greatly bent. Thus, the engine performance can be improved and the fuel consumption can be reduced.

  Since one of the throttle drum 67 and the throttle sensor 68 that are coaxially mounted on both ends of the valve shaft 66 of the throttle valve 65 is disposed on the main frame 13 side, the throttle is coaxially mounted on both ends of the valve shaft 66 of the throttle valve 65. The carburetor 39 can be brought close to the vehicle body center line C side while simplifying the configuration of the carburetor 39 by attaching the drum 67 and the throttle sensor 68.

  Furthermore, by arranging the throttle sensor 68 on the main frame 13 side, the throttle sensor 68 as an electrical component can be protected by the main frame 13.

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

  For example, in the above-described embodiment, the case where the present invention is applied to a motorcycle has been described. However, the present invention can also be implemented in connection with other small vehicles such as a motorcycle.

1 is a side view of a motorcycle. It is a principal part enlarged view of FIG. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a view taken along arrow 4 in FIG. 3. It is a vertical side view of a vaporizer.

11 ... Front fork 12 ... Head pipe 13 ... Main frame
13a ・ ・ Slightly inclined part
13b ... Steeply inclined portion 21 ... engine body 26 ... cylinder head 37 ... intake system 39 ... carburetor 44 ... recess 48 ... intake passage 65 ... throttle valve 66 ... · Valve shaft 67 · · · Throttle drum 68 · · · Throttle sensor C · · · Vehicle body center line F · · · Body frame IC · · · Intake axis

Claims (1)

A body frame (F) in the form of a backbone is connected to the head pipe (12) that supports the front fork (11) so as to be steerable, and is connected to the head pipe (12) in a straight line on the vehicle body center line (C) in plan view of the vehicle. A single main frame (13) extending in a shape, and the single main frame (13) includes a gently sloping portion (13a) having a rearward downward slope extending rearward from the head pipe (12) , A rearwardly inclined steeply inclined portion (13b) extending downward from a rear end of the gently inclined portion (13a), and the vehicle body frame (F) includes a lower portion than the gently inclined portion (13a) and the steep portion engine body (21) than (13b) disposed in front is mounted, the vaporizer contained in said engine body (21) an intake system communicating with the cylinder head (25) (37) (39) Has the viewed in a plan view of the vehicle the engine body (21) is inclined so that the vehicle body center line (C) closer towards the side and the side view of the vehicle steep portion (13b) and intersecting the intake axis line (IC) intake passage (48), the vaporizer in a small vehicle which is disposed on the side of the steep portion and a throttle valve (65) (13b) for controlling the amount of intake air flowing through the intake path (48) An arrangement structure ,
The intake axis (IC) of the intake passage (48) passes through the valve shaft (66) of the throttle valve (65) in a side view of the vehicle, and the valve shaft (66) on the steeply inclined portion (13b) side. A throttle sensor (68) is attached to one end, and a throttle drum (67) is coaxially attached to the other end.
A concave portion (44) that allows the vaporizer (39) to approach the vehicle body center line (C) side is formed on a side surface of the steeply inclined portion (13b) facing the vaporizer (39). In addition, the carburetor disposition structure in a small vehicle , wherein a part of the throttle sensor (68) is inserted into the recess (44) .

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