JP6303847B2 - Exhaust gas sensor mounting structure for motorcycles - Google Patents

Description

  The present invention relates to an exhaust gas sensor mounting structure for detecting exhaust gas of a motorcycle.

  2. Description of the Related Art Conventionally, in a motorcycle, a structure for exhausting engine exhaust gas through an exhaust pipe and a muffler has been adopted. An exhaust gas sensor is attached to a position near the engine of the exhaust pipe as disclosed in, for example, Patent Document 1. The exhaust gas sensor can detect whether the air-fuel ratio is rich or lean according to the oxygen concentration in the exhaust gas.

JP 2006-152962 A

  However, when the exhaust gas sensor is attached to the exhaust pipe as in Patent Document 1, the exhaust gas sensor becomes conspicuous in front of the engine, and there is a problem that the appearance of the motorcycle is impaired. In addition, a sensor for detecting exhaust gas is required to eliminate restrictions on the layout as much as possible while maintaining the appearance of the motorcycle.

  The present invention has been made in view of such points, and an object of the present invention is to provide an exhaust gas sensor mounting structure for a motorcycle that can attach an exhaust gas sensor inconspicuously and can increase the degree of freedom of the layout of the exhaust gas sensor. To do.

An exhaust gas sensor mounting structure for a motorcycle according to the present invention is an automatic vehicle including a muffler mounted on the downstream end side of an exhaust pipe through which exhaust gas from an engine flows, and a holding unit that holds an exhaust gas sensor that detects the exhaust gas. An exhaust gas sensor mounting structure for a motorcycle, wherein the motorcycle includes a brake pedal operated by a driver's foot, and the muffler is disposed outside the outer pipe and the outer pipe. The outer pipe includes a front portion formed in a tapered shape that decreases in diameter toward the front, and a recess is formed in a front region on an upper surface side of the front portion, and the holding portion is provided in the recess. The upper surface portion on the front end side of the inner pipe, and the bottom side forming portion of the recess in the front portion, Overlap in contact, the holding portion is a rear side of the brake pedal, a front region of the muffler is provided in a portion where the outer pipe and inner pipe are overlapped, the bottom side of the concave portion, the holding portion It forms in the shape which becomes high toward back from the side, and becomes low toward the front and the side from the said holding | maintenance part .

According to this configuration, since the exhaust gas sensor is held by the holding portion in the muffler front region, the exhaust gas sensor can be made less noticeable than when the exhaust gas sensor is attached to the exhaust pipe. As a result, the appearance of the exhaust pipe can be prevented from being damaged, and as a result, the overall appearance of the motorcycle can be improved. In addition, in a motorcycle, since the space behind the brake pedal is relatively free, the degree of freedom in the layout of the exhaust gas sensor can be increased. Moreover, the protrusion amount of the attached exhaust gas sensor can be suppressed by the amount of the concave portion. Accordingly, the exhaust gas sensor can be made inconspicuous also by this, and a stepping stone or the like can be made difficult to hit the exhaust gas sensor during traveling. Furthermore, since the holding part can be attached to the part where the outer pipe and the inner pipe are double, it becomes difficult for the heat of the exhaust gas to escape, and when there is a catalyst on the downstream side of the holding part, the catalyst is kept while keeping the heat of the exhaust gas. Can be flowed to.

  In the exhaust gas sensor mounting structure for a motorcycle described above, the holding portion and the exhaust gas sensor have a shape extending in a predetermined axial direction, and the axial line is set between a vertical direction and a direction inclined from the vertical direction toward the inside of the vehicle body. It is preferable that In this configuration, the exhaust pipe is disposed on the lower side in front of the exhaust gas sensor. Thereby, the exhaust gas sensor can be protected from external factors such as stepping stones from the front lower side of the vehicle.

In the exhaust gas sensor mounting structure of the motorcycle, the holding portion, said protruding from the inner peripheral surface of the inner pipe inwardly, the exhaust pipe, upon insertion of the rear end side thereof within the inner pipe, after the end Rukoto preferably abutting on the holding portion of the inside of the inner pipe. In this configuration, when the exhaust pipe is inserted into the muffler and assembled, the holding portion can be used as a stopper for the exhaust pipe, and the assemblability can be improved.

  According to the present invention, the exhaust gas sensor can be attached inconspicuously by holding the exhaust gas sensor in the holding portion in the front area of the muffler, and the degree of freedom of the layout of the exhaust gas sensor can be increased.

1 is a right side view showing a configuration of a motorcycle according to the present embodiment. It is a right view which shows a muffler, an exhaust pipe, and its surrounding structure. It is a schematic perspective view which shows a muffler front area | region. FIG. 4 is a plan view of FIG. 3. It is sectional drawing in the continuous line AA shown in FIG. It is a front view of a muffler and an exhaust gas sensor. It is the right view of the muffler which saw through the inside. It is sectional drawing in the continuous line BB shown in FIG. It is a front view similar to FIG. 6 which concerns on a modification. It is a schematic perspective view which shows the muffler front area | region which concerns on another modification. Furthermore, it is sectional drawing similar to FIG. 5 which concerns on another modification. It is sectional drawing similar to FIG. 8 which concerns on another modification.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following, an example in which the exhaust gas sensor mounting structure according to the present invention is applied to a naked type motorcycle will be described, but the application target is not limited to this and can be changed. For example, the exhaust gas sensor mounting structure according to the present invention may be applied to other types of motorcycles. Regarding the direction, the front of the vehicle is indicated by an arrow FR, the rear of the vehicle is indicated by an arrow RE, the left side of the vehicle is indicated by an arrow L, and the right side of the vehicle is indicated by an arrow R. In the following drawings, some components may be omitted for convenience of explanation.

  First, referring to FIG. 1, a schematic configuration of the entire motorcycle according to the present embodiment will be described. FIG. 1 is a right side view of the motorcycle according to the present embodiment.

  As shown in FIG. 1, a motorcycle 1 includes a body frame 2 made of steel or aluminum alloy on which a power unit and electrical components are mounted. The main tube 3 of the vehicle body frame 2 extends rearward from the head pipe 4 located at the front end. The down tube 5 of the vehicle body frame 2 is provided so as to extend rearward and obliquely downward from the head pipe 4. A fuel tank 7 in which fuel is accommodated is disposed behind the head pipe 4. A seat 8 on which a driver is seated is mounted behind the fuel tank 7. Below the seat 8, there is provided a footrest 9 that serves as a footrest for the driver during driving. A brake pedal 11 for the rear wheel 10 is provided in the vicinity of the footrest 9 on the right side of the vehicle body (the front side in FIG. 1). The brake pedal 11 is pivotally supported at a rear end portion located rearward of the footrest 9 and a front end portion located forward of the footrest 9 is swingably provided. The front end portion of the brake pedal 11 is depressed by a driver's foot placed on the footrest 9.

  A single cylinder engine 14 is suspended on the main tube 3 and the down tube 5 in the vehicle body frame 2. The engine 14 includes an engine case 16 supported by the down tube 5 via a bracket 15, and a cylinder 17 and a cylinder head 18 provided above the engine case 16. In the present embodiment, the cylinder 17 is connected to the upper side of the engine case 16 in a forwardly inclined state. A clutch side cover 19 is mounted on the right side of the vehicle body of the engine case 16 (front side in FIG. 1), and a magnet side cover (not shown) is provided on the left side of the vehicle body of the engine case 16 (back side in FIG. 1). It is installed.

  The cylinder head 18 is connected to the upper end (upstream end) side of the exhaust pipe 21, and exhaust gas discharged from the combustion chamber (not shown) of the cylinder 17 flows through the exhaust pipe 21 and is discharged from the rear muffler 22. A muffler cover 23 is attached to the muffler 22 so as to cover the upper surface side. An exhaust gas sensor 25 is attached to the front end (upstream end) side of the muffler 22. Each structure of the muffler 22 and the exhaust gas sensor 25 will be described later.

  A front fork 27 is rotatably supported at a front end portion of the main tube 3 via a steering shaft (not shown) provided in the head pipe 4. A handlebar 28 is provided at the upper end of the steering shaft, and grips 29 are attached to both ends of the handlebar 28. A front wheel 31 is rotatably supported on the lower portion of the front fork 27. An upper portion of the front wheel 31 is covered with a front fender 32.

  A rear wheel 10 is rotatably supported behind the engine 14 via a swing arm (not shown). Between the swing arm and the vehicle body frame 2, a suspension 35 is arranged to reduce the impact from the road surface. A rear fender 36 is disposed above the rear wheel 10 and behind the seat 8. Various body exteriors such as a cover are attached to the body frame 2.

  The detailed configuration of the muffler will be described with reference to FIGS. FIG. 2 is a right side view showing the muffler, the exhaust pipe and the surrounding structure. FIG. 3 is a schematic perspective view showing a muffler front region. FIG. 4 is a plan view of FIG. FIG. 5 is a cross-sectional view taken along the solid line AA shown in FIG. FIG. 6 is a front view of the muffler and the exhaust gas sensor. FIG. 7 is a right side view of the muffler as seen through the inside. 8 is a cross-sectional view taken along the solid line BB shown in FIG. In addition, the muffler 22 shown below shows an example, and is not limited to this configuration.

  As shown in FIG. 2, the muffler 22 includes a hollow outer pipe 40 exposed to the outside. The outer pipe 40 includes a front part 41, a center part 42, and a tail part 43 in order from the front. The center part 42 is formed in a cylindrical shape having a uniform cross section perpendicular to the extending direction. The tail portion 43 has a tapered shape with a diameter decreasing toward the rear, and forms an exhaust port 43a for exhaust gas exhaust.

  The front portion 41 is formed in a tapered shape that decreases in diameter toward the front. The rear end (downstream end) side of the exhaust pipe 21 is inserted into the front end side of the front portion 41, and the muffler 22 is attached to the exhaust pipe 21 by this insertion. As shown in FIGS. 3 and 4, a recess 45 is formed in the front region on the upper surface side of the front portion 41. A sensor boss (holding portion) 46 for attaching the exhaust gas sensor 25 (see FIG. 2) is provided inside the recess 45.

  As shown in FIGS. 5 and 6, a cylindrical inner pipe 48 is disposed on the inner side of the front portion 41 on the front end side. The front and rear positions of the front end of the inner pipe 48 are set to be the same as or slightly forward of the front end of the front portion 41. The outer diameter of the front end of the inner pipe 48 is the same as or slightly smaller than the inner diameter of the front end of the front portion 41. The upper surface portion on the front end side of the inner pipe 48 and the bottom-side formation portion of the recess 45 in the front portion 41 overlap each other in surface contact. The front and rear positions of the rear end of the inner pipe 48 are set behind the rear portion of the recess 45.

  As shown in FIG. 7, the rear end of the inner pipe 48 is connected to a catalyst device 50 having a cylindrical shape extending in the front-rear direction. The catalyst device 50 is disposed across the boundary position between the front portion 41 and the center portion 42. The catalyst device 50 includes a catalyst (not shown) for purifying exhaust gas, and is provided so as to purify the exhaust gas introduced from the front through the exhaust pipe 21 and the inner pipe 48 so as to be discharged rearward.

  A baffle pipe 52 is connected to the rear end of the catalyst device 50, and the baffle pipe 52 passes through two baffle plates 53 that partition the center portion 42 in the front-rear direction. A baffle pipe 54 located in the center portion 42 is also connected to the exhaust port 43a. In the muffler 22, every time it passes through the space partitioned by the baffle plate 53, the exhaust sound is attenuated to obtain a silent action.

  Next, the configuration of the exhaust pipe will be described with reference to FIGS. 1 and 5. As shown in FIG. 1, the exhaust pipe 21 is curved from the front of the cylinder head 18 and extends obliquely backward and downward, and passes through the front of the cylinder 17 and the engine case 16. Then, it curves in front of the engine case 16 and is directed rearward, extends rearward while passing under the engine case 16, and is connected to the muffler 22 behind the rear end of the brake pedal 11.

  As shown in FIG. 5, the exhaust pipe 21 has a double structure and includes an outer tube 21a and an inner tube 21b provided inside the outer tube 21a. A gap is formed between the outer tube 21a and the inner tube 21b, and the ends 21c are joined to close the space 21c in the gap.

  Next, the exhaust gas sensor and its mounting structure will be described with reference to FIGS.

  As shown in FIG. 6, the exhaust gas sensor 25 includes a stepped cylindrical sensor body 56 located outside the front portion 41, a sensing portion 57 located inside the front portion 41, a sensor body 56 and a sensing portion 57. And a male screw part 58 provided between the two. The sensor body 56 is provided in a shape in which the central axis extends in the vertical direction (vertical direction). In the exhaust gas sensor 25, the sensing unit 57 detects whether the air-fuel ratio is rich or lean according to the oxygen concentration in the exhaust gas. The voltage output from the sensing unit 57 changes depending on whether the air-fuel ratio is in a rich state or a lean state, and the ECU (Electronic Control Unit) below the seat 8 (see FIG. 1) via the sensor cord 59. , Not shown).

  The sensor boss 46 for mounting the exhaust gas sensor 25 is formed in a cylindrical shape whose central axis extends in the vertical direction (vertical direction), and an inner peripheral surface thereof is a female screw portion 46 a that is screwed into the male screw portion 58. As shown in FIGS. 5 and 8, the sensor boss 46 is joined to the front portion 41 and the inner pipe 48 in a state of passing through the inside and outside of the front portion 41. In this joining, the sensor boss 46 is inserted into the holes 45a, 48a formed in the bottom side of the recess 45 and the inner pipe 48 in the front portion 41, and in this state, the region near the holes 45a, 48a and the sensor boss 46 are welded. doing. In this welding, in the vicinity of the holes 45a and 48a, the inner pipe 48 and the front portion 41 are in surface contact and overlap with each other, so that the heat of the exhaust gas is difficult to escape and the catalyst device maintains the heat of the exhaust gas. 50.

  The sensor boss 46 protrudes inward from the inner peripheral surface of the inner pipe 48. By projecting the sensor boss 46 in this manner, when the rear end side of the exhaust pipe 21 is inserted into the inner pipe 48, the rear end can be abutted against the sensor boss 46. That is, the sensor boss 46 can be used as a stopper for the exhaust pipe 21 and the amount of insertion of the exhaust pipe 21 can be made constant. As a result, the relative position of the inner pipe 48 and the exhaust pipe 21 in the front-rear direction can be easily determined, and the assembling property can be improved.

  The exhaust gas sensor 25 is attached by screwing the male screw portion 58 of the exhaust gas sensor 45 into the female screw portion 46 a of the sensor boss 46. As a result, the exhaust gas sensor 25 is held on the sensor boss 46, and the center axis of the sensor body 56 is directed in the vertical direction (vertical direction) in this held state. Further, since the sensor boss 46 is provided in the front portion 41 which is the front area of the muffler 22 and the muffler 22 is provided behind the brake pedal 11 (see FIG. 1), the exhaust gas sensor 25 held by the sensor boss 46 is also in the brake pedal 11. It will be located behind.

  As described above, in the present embodiment, since the exhaust gas sensor 25 is provided in the front portion 41, the exhaust gas sensor 25 can be made inconspicuous as compared with the conventional structure in which the exhaust gas sensor is provided in the front region of the exhaust pipe. . Thereby, it can avoid that the external appearance around the exhaust pipe 21 is impaired, and the external appearance of the entire motorcycle 1 can be improved. In addition, since the exhaust gas sensor 25 protrudes from the bottom side of the recess 45, the height of the recess 45 and the protrusion height of the exhaust gas sensor 25 can be suppressed to make it less conspicuous.

  Here, as shown in FIG. 1, the components of the motorcycle 1 are not crowded around the front portion 41 of the muffler 22, so that there is a relatively large room, so the degree of freedom in changing the layout of the exhaust gas sensor 25 can be increased. Can be high.

  Further, since the exhaust gas sensor 25 is disposed upward from above the front portion 41, the exhaust gas sensor 25 can be protected by the muffler 22 and the exhaust pipe 21 from a stepping stone or the like from the front lower side of the vehicle body. Moreover, since the protrusion height of the exhaust gas sensor 25 is suppressed by the recess 45, the exhaust gas sensor 25 can be better protected.

  In addition, this invention is not limited to the said embodiment, It can change and implement variously. In the above-described embodiment, the size, shape, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. In addition, various modifications can be made without departing from the scope of the object of the present invention.

  For example, as shown in FIG. 9, the axial direction of the exhaust gas sensor 25 may be inclined inward (left side) in the width direction of the vehicle body from the vertical direction. According to this, the protrusion height of the exhaust gas sensor 25 can be further suppressed, and the exhaust gas sensor 25 can be better protected from a stepping stone or the like from the front lower side of the vehicle body.

  Moreover, you may change the front part 41 into the shape shown in FIG. In FIG. 10, the front part 41 is provided with a tapered part 41a and a cylindrical part 41b connected to the front end of the tapered part 41a, and the inner pipe 48 is inserted into the cylindrical part 41b. A sensor boss 46 is provided on the cylindrical portion 41 b, and the exhaust gas sensor 25 is held via the sensor boss 46.

  Furthermore, as shown in FIGS. 11 and 12, the inner diameter of the hole 48 a formed in the inner pipe 48 may be approximately the same as the female thread portion 46 a of the sensor boss 46. In this case, the sensor boss 46 is joined by performing welding in a state where the lower end surface of the sensor boss 46 is in contact with the outer surface of the inner pipe 48.

  The holding portion according to the present invention is not limited to the sensor boss 46, and may be changed as long as the exhaust gas sensor 25 can be held at the same position as the sensor boss 46.

  As described above, the present invention has an effect that an exhaust gas sensor can be attached inconspicuously, and is useful for a motorcycle in which a catalyst device is disposed inside a muffler.

DESCRIPTION OF SYMBOLS 1 Motorcycle 11 Brake pedal 14 Engine 21 Exhaust pipe 22 Muffler 25 Exhaust gas sensor 40 Outer pipe 45 Concave part 46 Sensor boss (holding part)
48 Inner pipe

Claims (3)

An exhaust gas sensor mounting structure for a motorcycle comprising a muffler mounted on the downstream end side of an exhaust pipe through which exhaust gas from an engine flows, and a holding unit for holding an exhaust gas sensor for detecting the exhaust gas,
The motorcycle includes a brake pedal operated by a driver's foot,
The muffler includes an outer pipe exposed to the outside, and an inner pipe disposed inside the outer pipe,
The outer pipe includes a front portion formed in a tapered shape that decreases in diameter toward the front, forms a recess in a front region on the upper surface side of the front portion, and provides the holding portion in the recess.
The upper surface portion on the front end side of the inner pipe and the bottom side forming portion of the recess in the front portion overlap in surface contact with each other,
The holding portion is behind the brake pedal , is a front region of the muffler, and is provided in a portion where the outer pipe and the inner pipe overlap,
The exhaust gas sensor mounting of a motorcycle , wherein a bottom side of the concave portion is formed in a shape that becomes higher from the holding portion toward the rear and lower from the holding portion toward the front and the side. Construction. The holding unit and the exhaust gas sensor have a shape extending in a predetermined axial direction, and the axial line is set between a vertical direction and a direction inclined from the vertical direction to the inside of the vehicle body. 2. An exhaust gas sensor mounting structure for a motorcycle according to 1 . The holding portion is protruded inwardly from the inner peripheral surface of the inner pipe,
The exhaust pipe, upon insertion of the rear end side thereof within the inner pipe, according to claim 1 or claim 2 said rear end and said Rukoto butting in the holding portion of the inside of the inner pipe The exhaust gas sensor mounting structure for a motorcycle described in 1.

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