Front cowl structure for saddle riding type vehicle

A front cowl structure for a saddle riding type vehicle for preventing turbulence in a stream of air flowing over a front cowl surface. The front cowl structure includes a duct placed inside a front cowl with a duct opening that opens to the front of the vehicle. The front cowl has a cowl front surface opening at a leading end portion thereof for opening a cowl front surface. Headlights are disposed on both lateral sides of the cowl front surface opening with each having a lens surface. The lens surfaces form opening edge portions on both lateral sides of the cowl front surface opening. The lens surfaces are each inclined to a vehicle outer side and rearwardly from the opening edge portions. The duct opening and a cowl opening central portion of the cowl front surface opening are substantially aligned with each other in a vehicle longitudinal direction.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 USC 119 to Japanese Patent Application No. 2012-217663 filed Sep. 28, 2012 the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to front cowl structures for saddle riding type vehicles. More specifically, to a front cowl structure for a saddle riding type vehicle including a front cowl having an intake opening.

2. Description of Background Art

A saddle riding type vehicle is disclosed, for example, in Japanese Patent Laid-Open No. 2010-149806. This saddle riding type vehicle includes a duct portion of an air cleaner, the duct portion opening forwardly in the vehicle with an air introducing opening formed forwardly of a front cowl corresponding to the open duct portion. This arrangement is designed to supply an airflow from the vehicle forward direction to an intake system for improved air-intake efficiency.

The structure disclosed in Japanese Patent Laid-Open No. 2010-149806, however, includes a duct portion that is inclined upwardly toward the rear of the vehicle. The airflow supplied to the duct portion is thus slightly bent and the structure is not properly designed to make the most of air pressure of the airflow.

In the structure having the air introducing opening forwardly of the front cowl, as in Japanese Patent Laid-Open No. 2010-149806, turbulence is more likely to occur in a stream of air flowing over a front cowl surface, causing the airflow blowing against a rider to be disrupted, thus degrading ride comfort.

During high speed riding, a stick phenomenon of the stream of air flowing in the air introducing opening creates a greater resistance acting on an operation of tilting the vehicle to the left or right.

SUMMARY AND OBJECTS OF THE INVENTION

The present invention has been made in view of the foregoing situation. It is an object of an embodiment of the present invention to provide a front cowl structure for a saddle riding type vehicle, capable of making the most of air pressure of an airflow than ever before to prevent turbulence in a stream of air flowing over a front cowl surface even with a structure having an air introducing opening forwardly of the front cowl. Thus, a stick phenomenon of the stream of air flowing in the air introducing opening is contained.

To achieve the foregoing object, according to an embodiment of the present invention, a front cowl structure for a saddle riding type vehicle, includes a front cowl for covering a vehicle leading end portion and a duct disposed on an inside of the front cowl. The duct is provided for drawing in air for use in an intake system that supplies an engine with air, wherein the duct has a duct opening that opens forwardly of the vehicle. The front cowl has a cowl front surface opening at a leading end portion thereof. The cowl front surface provides an opening for a cowl front surface. Headlights are disposed on both lateral sides of the cowl front surface opening each have a lens surface. The lens surface forms an opening edge portion on a corresponding lateral side of the cowl front surface opening and is inclined to a vehicle outer side and rearwardly from the opening edge portion. The duct opening is formed to be substantially aligned with a cowl opening central portion of the cowl front surface opening in a vehicle longitudinal direction.

According to an embodiment of the present invention, the cowl front surface opening is formed to be larger than the duct opening so that all opening edge portions of the duct opening are visible as viewed from a vehicle forward side.

According to an embodiment of the present invention, the cowl front surface opening has a shouldered portion such that an entrance side wall of an opening entrance portion on the vehicle forward side has an opening width that is narrower than an opening width of a communicating path side wall of a communicating path that communicates with the duct opening.

According to an embodiment of the present invention, the cowl front surface opening is formed substantially into an M-shape including pairs of left and right taper edge portions that extend to taper toward a rear of the front cowl, and a boundary line portion between a cowl upper surface center portion. A cowl upper surface side portion on either lateral side of the front cowl is formed to be joined to the taper edge portions.

According to an embodiment of the present invention, the boundary line portion between the cowl upper surface center portion and the cowl upper surface side portion is formed into a recess that extends from a merging vertex of the taper edge portions rearwardly of the front cowl.

According to an embodiment of the present invention, the lens surface is inclined such that an entire surface thereof faces downwardly and rearwardly of the vehicle.

According to an embodiment of the present invention, the duct opening that opens forwardly of the vehicle is formed to be substantially aligned in the vehicle longitudinal direction with the cowl opening central portion of the cowl front surface opening that opens the cowl front surface at the leading end portion of the front cowl. A stream of air entering the duct opening while the vehicle is being operated can have part of the flow at the highest speed disposed at the central portion of the duct opening without being affected by the vehicle body shape, so that ram pressure of the stream of air flowing in the duct can be maximized to thereby achieve an effective drawing of air. In addition, the headlights disposed on both lateral sides of the cowl front surface opening each has a lens surface, the lens surface forming an opening edge portion on a corresponding lateral side of the cowl front surface opening and being inclined to the vehicle outer side and rearwardly from the opening edge portion. No step is thus formed of a connection between the headlight on either lateral side of the cowl front surface opening and the front cowl. Turbulence in the airflow does not therefore occur at the opening edge portions and the airflow that flows into the duct can be drawn as a laminar flow.

According to an embodiment of the present invention, the cowl front surface opening is formed such that all opening edge portions of the duct opening are visible as viewed from the vehicle forward side. No obstacles are formed that block inflow of air exist in an area forward of the duct opening. Thus, a smooth inflow of air and effective drawing of air is provided.

According to an embodiment of the present invention, the cowl front surface opening has a shouldered portion such that the entrance side wall of the opening entrance portion on the vehicle forward side has an opening width that is narrower than an opening width of the communicating path side wall of the communicating path that communicates with the duct opening. The shouldered portion can separate the stream of air flowing into the cowl front surface opening from the communicating path side wall, thus avoiding sticking of the stream of air onto the communicating path side wall. Thus, vehicle turning performance can thereby be improved.

According to an embodiment of the present invention, the cowl front surface opening is formed substantially into an M-shape including the pairs of left and right taper edge portions that extend to taper toward the rear of the front cowl. Thus, the boundary line portion between the cowl upper surface center portion and the cowl upper surface side portion on either lateral side of the front cowl is formed to be joined to the taper edge portions. A stream of air flowing from the opening edge portion of the cowl front surface opening to a cowl outer surface can thus be guided along the taper edge portions to flow along the cowl outer surface profile. This creates a stream of air flowing along the profile of the upper surface of the front cowl to thereby contain turbulence in the stream of air. Thus, a smooth airflow flowing over the upper surface of the front cowl is provided. As a result, the airflow flowing over the upper surface of the front cowl is smooth to provide a gentle airflow that blows against the rider.

According to an embodiment of the present invention, the boundary line portion between the cowl upper surface center portion and the cowl upper surface side portion is formed into a recess that extends from the merging vertex of the taper edge portions rearwardly of the front cowl. A turbulent flow produced at the opening edge portion of the cowl front surface opening can thus be made to flow from the merging vertex of the taper edge portions through the inside of the boundary line portion having a recessed shape to the rear of the front cowl. A laminar flow portion and a turbulent flow portion on both lateral sides of the cowl can thereby be properly isolated from each other, so that an adverse effect from the turbulent flow on the laminar flow can be minimized and the laminar flow can be maintained to minimize operating resistance.

According to an embodiment of the present invention, the lens surface is inclined such that the entire surface thereof faces downwardly and rearwardly of the vehicle. Even when the lens surface is made large, the foregoing aspect of the present invention allows a lens area to be held small and a front cowl area to be large when viewed from the front side. Airflow smoothing action by the front cowl can therefore be improved.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A specific embodiment to which the present invention is applied will be described below.

A saddle riding type vehicle, such as a motorcycle, according to an embodiment of the present invention will be described in detail below with reference toFIGS. 1 to 8.

The drawings should be viewed in the direction of the reference numerals. The drawings show arrows to indicate directions relative to an operating direction of the motorcycle, an arrow Fr denoting a vehicle forward direction, an arrow Rr denoting a vehicle rearward direction, an arrow Up denoting a vehicle upward direction, and an arrow Dw denoting a vehicle downward direction, respectively.

FIG. 1is a side elevational view showing a motorcycle100according to an embodiment of the present invention.

The motorcycle100includes a vehicle body frame50having a framework on which various component parts are attached. The vehicle body frame50includes a head pipe51disposed at a vehicle front end portion and a pair of left and right main frames50athat branch laterally from the head pipe51and extend obliquely downwardly toward the rear. An engine1is held on a lower side of the main frames50aas appropriate. A front fork53that supports a front wheel58is steerably supported on the head pipe51. A steering handlebar55is connected to an upper portion of the front fork53.

A rear fork56that supports a rear wheel59is vertically swingably supported on the vehicle body frame50. The rear fork56is suspended as appropriate on the main frames50avia suspension means.

A fuel tank60is disposed at an upper portion of the main frames50aof the vehicle body frame50. A riding seat61including a rider's seat61aand a passenger's seat61bis disposed at a rear portion of the vehicle body frame50.

A pair of left and right seat rails50bis disposed rearwardly of the vehicle body frame50extending obliquely upwardly from a rear end portion of the main frames50ato the rear. The riding seat61, for example, is held on the seat rails50b.

The motorcycle100according to the first embodiment of the present invention has an outside covered in a vehicle body cover3as appropriate. More specifically, the vehicle body cover3covers vehicle component parts and electrical parts as appropriate and includes, for example, a front cowl10, a side cowl13, a bottom cowl14, a seat lower cover15and a rear cover16. The front cowl10covers a vehicle front portion side as a vehicle leading end portion100a. The side cowl13covers parts extending from an upper portion side surface side of the engine1to a downward side of the fuel tank60at an area rearwardly of the front cowl10. The bottom cowl14covers a downward side of the engine1. The seat lower cover15covers parts extending from a rearward side of the side cowl13to a downward side of the rider's seat61a. The rear cover16covers a lower side of the passenger's seat61bat an area rearward of the seat lower cover15. It is noted that the vehicle body cover3is substantially symmetrical in shape on both sides of the vehicle for covering the vehicle body.

The front cowl10, the side cowl13, the bottom cowl14, the seat lower cover15, and the rear cover16are fixed to the vehicle body via, for example, mounting screws41,42,43and44, as appropriate.

In the embodiment of the present invention, a pair of left and right headlights18,18is disposed at a leading end portion10tof the front cowl10. The headlights18,18are each formed into a horizontally long, substantially rectangular shape extending from a front surface side of the front cowl10to a corresponding lateral surface, so that a lens surface18ais formed into an outer surface shape extending substantially along a cowl outer surface. The headlights18,18are thus formed so that air flows smoothly along the lens surfaces18a,18awhile the vehicle is being operated. The front cowl10has a cowl front surface opening11to be described later (seeFIG. 2) formed between the left and right headlights18,18.

As shown inFIG. 2, the front cowl10and the side cowl13generally cover, on a side upward of a front fender54, parts other than a rearview mirror17, a direction indicator19, and the handlebar55that are members protruding in a vehicle width direction. The front cowl10and the side cowl13are designed to achieve smooth streams of air along the upper and side portions of the vehicle. The front cowl10, in particular, uses an airflow to generate a down force as appropriate, thereby contributing to steady vehicle operation.

In the embodiment of the present invention, an air cleaner case5a(seeFIG. 1) of an intake system5is disposed at a position upward of the engine1and beneath the fuel tank60. A duct20(seeFIG. 1) that extends toward a vehicle front portion is connected to the air cleaner case5a. The duct20has a duct opening21that opens toward the front of the vehicle. The cowl front surface opening11that is an opening in the front surface of the front cowl10is disposed on a forward side of the duct opening21. An air stream path free of protrusions to obstruct an inflow of air is formed between the cowl front surface opening11and the duct20. Thus, air forward of the vehicle is supplied from the cowl front surface opening11in the cowl front surface to the air cleaner case5avia the duct20.

Though portions of the intake system5close to the engine1are not shown, the air cleaner case5ais connected as appropriate to a throttle body (not shown) connected to an intake port of the engine1. The air cleaner case5ahas a filter element (not shown) disposed thereinside. A clean air chamber downstream in the stream of air of the filter element is connected to the throttle body and the duct20is connected to an upstream side in the stream of air of the filter element.

The throttle body includes an injector and a throttle valve disposed therein, the injector injecting fuel and the throttle valve being oscillatable and regulating an intake air amount. Air supplied through the duct20is mixed with fuel in the throttle body and supplied as a mixture of gas to the intake port of the engine1.

As shown inFIGS. 2 and 3, in the embodiment of the present invention, the cowl front surface opening11is disposed between the headlights18,18at a frontmost end of the front cowl10that covers the vehicle leading end portion100a. The cowl front surface opening11is formed such that a center thereof in a vehicle height direction is on a level substantially equal to a height of extreme leading end portions10te,10te(at two places on both lateral sides of the cowl front surface opening11) of the front cowl10. The cowl front surface opening11is disposed relative to the extreme leading end portions10te,10teas follows. More specifically, referring toFIG. 1, when the motorcycle100is viewed from a side, the cowl front surface opening11is formed to extend over a range that expands vertically in upper and lower directions from and about the extreme leading end portion10te. When viewed from a vehicle forward direction, the cowl front surface opening11is formed between the extreme leading end portions10te,10teand between the headlights18,18.

The headlights18,18disposed on both sides of the cowl front surface opening11each have the lens surface18a. The lens surfaces18a,18aform opening edge portions11ed,11edon both lateral sides of the cowl front surface opening11. In addition, the lens surfaces18a,18aare each inclined to a vehicle outer side and rearwardly from the opening edge portions11ed,11ed. The lens surfaces18a,18aof the headlights18,18disposed on both sides of the cowl front surface opening11, are formed into smooth edge shapes as the opening edge portions11ed,11edon both sides of the cowl front surface opening11as described above, to prevent turbulence of the airflow from the vehicle forward direction from occurring when the airflow is divided into a lens surface side wind f18and an opening inside side wind f11. This allows the airflow that flows into the cowl front surface opening11to be drawn as a laminar flow.

In addition, in the embodiment of the present invention, the lens surface18aof the headlight18is inclined such that an entire surface thereof faces downwardly as shown inFIG. 1. The lens surface18ais inclined so as to have the entire surface not only facing downwardly, but also extending rearwardly to follow along a cowl outer surface toward a corresponding lateral outer side in the vehicle lateral direction as shown inFIGS. 2 and 3.

As described above, the lens surface18ais inclined so as to have the entire surface facing downwardly and rearwardly. Even when the lens surface is made large, the foregoing arrangement allows a lens area to be held small and a front cowl area to be large when viewed from the front side. As a result, a greater amount of air can be blown against the front cowl10, so that the front cowl10can achieve enhanced laminar flow adjusting the ability of the airflow.

Referring toFIGS. 2 and 3, shapes of the cowl front surface opening11and its surrounding parts according to the embodiment of the present invention will be described below.

As shown inFIGS. 2 and 3, the front cowl10includes a cowl upper surface center portion10cat the center of the cowl upper surface and cowl upper surface side portions10s,10son both lateral sides of the cowl upper surface center portion10c. More specifically, the cowl upper surface center portion10cis formed into a curved surface that is joined to taper edge portions11kb,11kbthat assume upper edge portions of the cowl front surface opening11. The cowl upper surface side portions10s,10sare formed into curved surfaces that are joined to taper edge portions11ka,11kathat assume side edge portions of the cowl front surface opening11.

Thus, boundary line portions10cs,10csbetween the cowl upper surface center portion10cand the cowl upper surface side portions10s,10sare each formed into a recessed line at which different curved surfaces merge. Additionally, the cowl front surface opening11formed substantially into an M-shape is formed such that the boundary line portions10cs,10csextend rearwardly from merging vertices11e,11eof the pairs of left and right taper edge portions11kaand11kbtoward the rear of the front cowl.

As described above, the cowl front surface opening11has an upper half portion shaped substantially into an M-shape, the merging vertices11e,11eare formed so as to overlap the boundary line portions10cs,10cs, and the boundary line portions10cs,10csare formed to extend rearwardly of the cowl. Therefore, guiding winds fka and fkb can be produced at the edge portions of the upper half portion of the cowl front surface opening11, the guiding winds fka and fkb guiding to the merging vertices11e,11edisturbed airflows that occur when the airflow is divided into one flowing into the opening and one flowing onto the outside of the opening, and the guiding winds fka and fkb are made to flow rearwardly of the front cowl as boundary line winds fcs that flow through the boundary line portions10cs,10cshaving a recessed shape. As a result, a laminar flow portion and a turbulent flow portion on both lateral sides of the front cowl can be properly isolated from each other, so that an adverse effect from the turbulent flow on the laminar flow can be minimized and a steady stream of air can be produced so that the stream of air flows to follow the shape of the upper surface of the front cowl10.

Turbulence in the stream of air is contained and the airflow flowing over the upper surface of the front cowl10is smoothed as described above. The airflow flowing over the upper surface of the front cowl10and blowing against the rider can thus be turned to a gentle airflow.

A structure of the duct20according to the embodiment of the present invention will be described.

As shown inFIGS. 4 and 5, the duct20has the duct opening21disposed rearwardly of, and corresponding to, the cowl front surface opening11. The duct opening21has a rectangular shape in its transverse cross section and opens toward the front of the vehicle. As viewed from the front of the vehicle, the duct opening21is disposed such that a duct opening central portion21athereof is disposed between the extreme leading end portions10te,10teof the front cowl10. More specifically, as shown inFIG. 5, the cowl front surface opening11has a cowl opening central portion11aaligned with the duct opening central portion21ain a vehicle longitudinal direction. This is translated, when viewed from a side of the vehicle (seeFIG. 1), to the duct opening central portion21aof the duct opening21, the cowl opening central portion11aof the cowl front surface opening11, and the extreme leading end portions10te,10teof the front cowl10being disposed on a longitudinal axis CL.

Referring toFIG. 6, a bulkhead22is disposed rearwardly of the duct opening21. The bulkhead22has a pair of circular communicating holes23,23arrayed laterally. In addition, the bulkhead22has, for example, a vertical rib22athat extends vertically and is disposed at a lateral center and a plurality of horizontal ribs22bthat extend laterally. The strength of the bulkhead22is thus reinforced.

In the embodiment of the present invention, the duct20includes a leading end portion20c, an enlarged-diameter portion20d, a constricted portion20e, and a branching portion20fconnected in a row to each other in the vehicle longitudinal direction and substantially horizontally. More specifically, the leading end portion20chaving the duct opening21is formed, for example, into a rectangle in its transverse cross section having a bottom side wall20dwslightly shorter in length than an upper side wall20upas shown inFIG. 5. The leading end portion20cis shaped so as to substantially correspond to an opening shape of the cowl front surface opening11. The enlarged-diameter portion20ddisposed rearwardly of the leading end portion20cis shaped to be larger in the lateral direction than the leading end portion20c. The bulkhead22is disposed inside the enlarged-diameter portion20d. The constricted portion20eis disposed rearwardly of the enlarged-diameter portion20dbetween the left and right front forks53,53. The branching portion20fis formed as a flow path that extends rearwardly from the constricted portion20eand branches laterally so as to sandwich the head pipe51.

Referring toFIGS. 4 and 6, light source mounting portions30of the headlights18,18are formed on both lateral sides of the leading end portion20cof the duct20.

The duct opening central portion21aof the duct opening21is aligned with the cowl opening central portion11aof the cowl front surface opening11in the front cowl10in the vehicle longitudinal direction as described earlier. A stream of air f1entering the duct opening21while the vehicle is being operated can thus further flow without being affected by the vehicle body shape as shown inFIGS. 4 and 5. Thus, the stream of air f1is able to enter directly the duct opening21as a stream of air with the highest speed. Consequently, ram pressure of the stream of air f1flowing in the duct20can be maximized to thereby enable an effective supply of air through the duct opening21.

The bulkhead22in the embodiment of the present invention is, for example, inclined so that a front surface of an upper side portion22upthereof faces forwardly and upwardly as shown inFIG. 6. The upper side portion22upincludes the communicating holes23,23.

The bulkhead22disposed in the duct20can, for example, prevent rainwater that has entered the cowl front surface opening11from reaching far into the duct20. In addition, the communicating holes23,23are open slightly upwardly.

The cowl front surface opening11is formed such that all opening edge portions21bof the duct opening21are visible as viewed from the front of the vehicle (seeFIG. 2). More specifically, the cowl front surface opening11is formed forwardly of the duct opening21so as to be free from any portions obstructing the duct opening21.

As described above, the cowl front surface opening11is formed such that all opening edge portions21bof the duct opening21are visible as viewed from the front of the vehicle and so as to be free from any portions obstructing the duct opening21forwardly thereof. An extremely smooth inflow of air into the duct opening21can therefore be achieved, thus enabling the supply of air that is effective in increasing the ram pressure.

As shown inFIG. 4, an entrance side wall11bwof an opening entrance portion11bon the vehicle forward side has an opening width W1that is narrower than an opening width W2of a communicating path side wall11cwof a communicating path11c. In addition, referring toFIG. 7, a shouldered portion11dhaving a shoulder width W3is formed between the entrance side wall11bwand the communicating path side wall11cwat an upper portion of the cowl front surface opening11.

An effect of the shouldered portion11dwill be described in detail below with reference toFIGS. 7 and 8.

In the cowl front surface opening11of the embodiment of the present invention, the opening width W1of the entrance side wall11bwat the opening entrance portion11bon the vehicle forward side is narrower than the opening width W2of the communicating path side wall11cw. This forms the shouldered portion11dthat is wider on the inside having a shoulder width W3between the entrance side wall11bwon the forward side and the communicating path side wall11cwon the rearward side.

When the stream of air f1enters the cowl front surface opening11, part of the stream of air f1close to the wall surface is pulled in the direction of the communicating path side walls11cwon both lateral sides (FIG. 7shows the right-hand side of the vehicle only) because of the shouldered portion11dformed in the foregoing manner, thus forming a vortex flow12. The formation of the vortex flow f2causes the stream of air f1to be separated from the left and right communicating path side walls11cw, thus avoiding sticking of the stream of air f1onto the communicating path side walls11cw. The avoidance of the sticking of the stream of air f1onto the communicating path side walls11cwallows, for example, resistance to be minimized when the vehicle is to be operated to be leaned to the left or right, thus improving vehicle turning performance.

As shown inFIG. 8, in the embodiment of the present invention, the shouldered portion11dis formed not only on both lateral sides of the cowl front surface opening11, but also, for example, between the entrance side wall11bwat the upper portion of the cowl front surface opening11and the communicating path side wall11cwon the rearward side, at which the shoulder width W4wider than those on both lateral sides is formed. Accordingly, the shouldered portion11dis formed continuously on both lateral sides and the upper side of the cowl front surface opening11.

In the embodiment of the present invention described heretofore, the duct opening21is formed into a rectangle. The duct opening21is not necessarily formed into a rectangle and may be formed into an elliptic or circular shape. In the above-described embodiment of the present invention, the bulkhead22has two communicating holes23as part of the structure of the duct20. However, this is not the only possible arrangement.

The above-described embodiment of the present invention has been described for a case in which the present invention is applied to a motorcycle. The present invention is nonetheless applicable to saddle riding type vehicles of various other types.