JP2012047303A - Cooling structure of belt type automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling structure of a belt type automatic transmission in which an inlet of an introducing duct can be arranged in the place where the winding up of dusts and water is small while securing the passage cross-sectional area of the introducing duct for introducing outside air.SOLUTION: In the scooter type motor cycle constituted such that the engine 116 in which a cylinder assembly 114 is forwardly inclined and extended from the crank case 115 and the belt type automatic transmission 117 extending rearward from one side in the right and left direction of the engine 116 and transmitting drive force to the rear wheel 118 are integrally constituted and are supported oscillatably up and down to the vehicle body, the inlet 167 of the introducing duct 150 for introducing the outside air into the belt case 143 of the belt type automatic transmission 117 is fixed to the vehicle body part 126 located in the other side in the right and left direction.

Description

  The present invention relates to a cooling structure for a belt-type automatic transmission in a scooter type motorcycle. In particular, the present invention relates to a cooling structure that cools a V-belt of a belt-type automatic transmission by introducing outside air into a belt case of the belt-type automatic transmission.

  2. Description of the Related Art A scooter type motorcycle having a belt type automatic transmission using a V belt is known. In the belt type automatic transmission, since the V belt generates heat due to friction between the pulley and the V belt, a cooling structure for cooling the V belt is required. Conventionally, a cooling structure in which outside air is introduced into a case of a belt-type automatic transmission through a cooling duct in order to cool the V-belt (see, for example, Patent Document 1 and Patent Document 2). In such a cooling structure, the suction port of the cooling duct may be arranged on the front side or the upper side of the belt type automatic transmission.

Japanese Patent No. 4134596 Japanese Patent No. 4190052

However, when the suction port of the cooling duct is on the front side of the belt-type automatic transmission, the suction port is located at a low vehicle height, so that dust and water rolled up by the front wheels are easily sucked from the suction port of the cooling duct, The belt type automatic transmission has problems such as belt slip. Therefore, it is necessary to provide a cover or the like at the suction port.
On the other hand, when the suction port of the cooling duct is on the upper side of the belt-type automatic transmission as in Patent Document 1 or in the center in the vehicle width direction as in Patent Document 2, other parts such as a fuel injection device are used. There is a risk of interference, and there is a problem that it is difficult to secure a sufficient cross-sectional area for cooling the V-belt.

  The present invention has been made in view of the above-described problems, and secures the passage cross-sectional area of the introduction duct that introduces outside air, while the introduction port of the introduction duct is placed in a place where there is little rolling of dust and water. It is an object of the present invention to provide a cooling structure for a belt type automatic transmission that can be arranged.

The present invention integrally integrates an engine in which a cylinder assembly is extended forwardly from a crankcase and a belt-type automatic transmission that extends from one side to the rear side in the left-right direction of the engine and transmits power to a rear wheel. In a scooter type motorcycle that is configured to be swingable up and down with respect to the vehicle body, an introduction port of an introduction duct for introducing outside air into a belt case of the belt type automatic transmission has the left and right sides It is fixed to the vehicle body part located on the other side in the direction.
Further, the introduction port is disposed on the front side of the vehicle body with respect to the belt type automatic transmission.
A flexible portion is formed in a part of the introduction duct.
The flexible portion is formed along the front-rear direction of the vehicle body.
The introduction duct includes a transverse duct portion coupled to the belt case and disposed along a left-right direction of the vehicle body, and a front and rear duct portion coupled to the transverse duct portion and extending toward the front side of the vehicle body. And an introduction part that is coupled to the front end of the front and rear duct part and is formed with the introduction port that opens to the outside of the vehicle body.

  ADVANTAGE OF THE INVENTION According to this invention, the introduction port of an introduction duct can be arrange | positioned in a place with little dust and water rolling up, ensuring the channel | path cross-sectional area of the introduction duct which introduces external air.

1 is a right side view of a scooter type motorcycle according to an embodiment. It is the left view which removed the vehicle body cover of the scooter type motorcycle. Fig. 3 is a right side view of the scooter type motorcycle with a body cover removed. It is a left view of the power unit which concerns on this embodiment. It is a right view of the power unit which concerns on this embodiment. It is a top view of the power unit concerning this embodiment. It is the perspective view which looked at the power unit which concerns on this embodiment from the rear side. It is the perspective view which looked at the power unit concerning this embodiment from the front side. It is the perspective view which looked at the power unit which concerns on this embodiment from the back side and the upper side. It is a perspective view which shows the state which attached the introduction duct to the vehicle body cover which concerns on this embodiment. It is the perspective view which looked at the inlet of the introduction duct concerning this embodiment from the side.

A preferred embodiment of a scooter type motorcycle having a cooling structure for a belt type automatic transmission according to the present invention will be described below with reference to the drawings.
First, the overall configuration of the scooter type motorcycle 100 will be described with reference to FIGS. 1, 2A and 2B. FIG. 1 is a right side view of a scooter type motorcycle according to the present embodiment. 2A and 2B are a left side view and a right side view with the vehicle body cover and the like removed. In each drawing, the front side of the vehicle body is indicated by arrow Fr, the rear side of the vehicle body is indicated by arrow Rr, the right side of the vehicle body is indicated by arrow R, and the left side of the vehicle body is indicated by arrow L as necessary.

  The scooter type motorcycle 100 (hereinafter referred to as a motorcycle) has a vehicle body skeleton formed of a plurality of vehicle body frames made of steel or aluminum alloy. Specifically, a steering head pipe 101 is disposed at the front of the vehicle body. A down tube 102 is extended substantially obliquely downward and rearward at a substantially central portion of the steering head pipe 101. In the vicinity of the lower end of the down tube 102, a pair of underframes 103 extend substantially rearward. A main frame 104 extends substantially upward at each of the substantially rear ends of the pair of underframes 103. A rear frame 105 is coupled to each of the upper ends of the pair of main frames 104. The pair of rear frames 105 extends obliquely upward to the rear side over the rear side of the vehicle body.

  As shown in FIG. 1, the steering head pipe 101 supports a front fork 106 in a rotatable manner. A handlebar 107 for steering is disposed at the upper end of the front fork 106 along the left-right direction, and a front wheel 108 is rotatably supported at the lower end. The front wheel 108 is covered with a front fender 127.

  A bracket 109 for supporting a power unit including the engine is additionally provided at the rear end of the under frame 103. On the bracket 109, a stay 111 is disposed substantially rearward via a first pivot shaft 110. In addition, a swing type power unit 113 is supported on the stay 111 via a second pivot shaft 112. The power unit 113 can swing up and down around the first pivot shaft 110 and the second pivot shaft 112 (mainly the second pivot shaft 112).

As shown in FIGS. 2A and 2B, the power unit 113 is a unit in which an engine 116 including a cylinder assembly 114 and a crankcase 115 and a belt-type automatic transmission 117 are unitized. Details of the power unit 113 will be described later.
A rear wheel 118 is rotatably supported at the rear portion of the belt-type automatic transmission 117. As shown in FIG. 1, the rear wheel 118 is covered with a rear fender 128. A shock absorber 119 is connected between the belt-type automatic transmission 117 and the rear frame 105. The shock absorber 119 absorbs vertical swing of the rear wheel 118 and the power unit 113.

As shown in FIG. 6 to be described later, an air cleaner box 120 is mounted on the upper side of the belt type automatic transmission 117. The intake air from the air cleaner box 120 is sucked into the cylinder assembly 114 together with the fuel, burned, and then exhausted from the muffler 135 as exhaust gas.
A seat 121 for a rider to sit on is installed on the upper side of the power unit 113. Further, on the upper side of the under frame 103, a step board 122 on which a rider's feet seated on the seat 121 is placed is supported by a step frame 123 (see FIGS. 2A and 2B). A luggage box 124 is disposed between the power unit 113 and the seat 121 as a storage space for storing a helmet or the like.

  As the vehicle body appearance, various vehicle body covers are supported and attached at appropriate places such as a vehicle body frame, and the appearance is adjusted. A front leg shield 125 covers the periphery of the down tube 102 at the front of the vehicle body. A frame cover 126 covers the periphery of the main frame 104 and the rear frame 105 from the center to the rear of the vehicle body. The front leg shield 125 and the frame cover 126 are integrally connected via the step board 122 described above.

Next, the configuration of the power unit 113 will be described with reference to FIGS. 3 is a left side view of the power unit, FIG. 4 is a right side view of the power unit, and FIG. 5 is a plan view of the power unit.
As described above, the power unit 113 includes the engine 116 including the cylinder assembly 114 and the crankcase 115 and the belt-type automatic transmission 117. The cylinder assembly 114 extends so that a piston axis p (not shown) tilts forward from the crankcase 115 to a horizontal state. As the piston in the cylinder assembly 114 reciprocates, the crankshaft in the crankcase 115 rotates in one direction. As shown in FIG. 5, the rotation axis c of the crankshaft is oriented in the width direction (left-right direction) of the vehicle body.

As shown in FIG. 4, a cooling fan (not shown) is provided on the right side of the crankcase 115 so as to face the air inlet 129. The cooling fan is attached to the right end of the crankshaft and rotates in synchronization with the crankshaft. The outer periphery of the cooling fan and the cylinder assembly 114 are covered with a cooling air cowling 130. Therefore, when the cooling fan rotates, outside air is taken into the cooling air cowling 130 to forcibly cool the cylinder assembly 114.
Above the crankcase 115, a starter motor 131 that rotates the crankshaft via a plurality of gears (not shown) when the engine 116 is started is disposed.

  On the left side of the crankcase 115, as shown in FIGS. 3 and 5, a belt-type automatic transmission 117 is extended toward the rear side. In the broken line shown in FIG. 5, the configuration of the belt-type automatic transmission 117 is extracted and shown. As shown in FIG. 5, the belt-type automatic transmission 117 includes a driving pulley 140, a driven pulley 141, and a V-belt 142 wound between the pulleys arranged in a belt case 143.

  The drive pulley 140 is pivotally attached to a crankshaft 144 that extends into the belt case 143. The driving pulley 140 rotates in synchronization with the crankshaft 144, and the effective diameter of the driving pulley 140 is expanded by moving the internal weight roller in the radial direction in accordance with an increase in centrifugal force. On the contrary, since the effective diameter of the driven pulley 141 is reduced, the speed is steplessly changed according to the rotational speed of the crankshaft 144 and transmitted to the driven shaft 145. A centrifugal clutch 146 is provided on the left side of the driven pulley 141. The centrifugal clutch 146 blocks the transmission of rotation from the driven pulley 141 to the driven shaft 145 in the low rotation region of the crankshaft 144.

On the right side of the driven shaft 145, a mission mechanism 147 including a plurality of gears (not shown) is provided. The mission mechanism 147 decelerates the rotation of the driven shaft 145 and transmits it to the rear wheel shaft 148. In this way, the belt-type automatic transmission 117 can automatically change gears in a stepless manner according to the rotational speed of the crankshaft 144.
Further, as shown in FIG. 5, a fan 134 is integrally provided at the left end of the drive pulley 140 for forcibly introducing outside air into the belt case 143 from the outside. Further, on the left side surface of the belt case 143, a discharge hole 149 for discharging outside air introduced into the belt case 143 to the outside is opened as shown in FIG.

  In the belt-type automatic transmission 117 configured as described above, when the effective diameters of the driving pulley 140 and the driven pulley 141 increase or decrease, the V-belt 142 slides on the driving pulley 140 and the driven pulley 141 in the radial direction. That is, friction occurs between the V belt 142 and the driving pulley 140 and the driven pulley 141, and the V belt 142 generates heat. Therefore, the belt type automatic transmission 117 requires a cooling structure for cooling the V belt 142.

Hereinafter, the cooling structure of the belt-type automatic transmission according to the present embodiment will be described.
In this embodiment, the V-belt 142 that has generated heat is cooled by introducing outside air into the belt case 143 of the belt-type automatic transmission 117. When introducing outside air into the belt case 143, it is necessary to arrange an introduction port for taking in outside air from the outside.
At this time, it is conceivable to arrange the introduction port on the front side of the belt-type automatic transmission 117. However, since the belt-type automatic transmission 117 is at a low vehicle height, the front wheel 108 and the rear wheel 118 are connected to the introduction port. The dust and water that are wound up easily enter the belt case 143.
It is also conceivable to arrange the introduction port on the front side and the upper side of the belt type automatic transmission 117. However, in the present embodiment, as shown in the perspective view showing the configuration around the power unit in FIG. 6, the air cleaner box 120 is disposed on the upper side of the belt-type automatic transmission 117, and the air cleaner box 120 faces the front side. An air duct 132 is disposed. Therefore, many parts are arranged on the front side and the upper side of the belt-type automatic transmission 117, and the introduction port cannot be made large.

  Therefore, in this embodiment, the introduction port 167 of the introduction duct 150 is arranged on the right side opposite to the belt-type automatic transmission 117 arranged on the left side in the width direction of the vehicle body. Outside air is sent from the introduction part 165 formed with the introduction port 167 to the belt case 143 of the belt-type automatic transmission 117 using the front and rear duct parts 158 and the transverse duct part 151. Hereinafter, the arrangement of the introduction duct 150 will be described in detail with reference to FIGS. FIG. 7 is a perspective view of the power unit as seen from the front side. FIG. 8 is a perspective view of the power unit as seen from the rear side.

As shown in FIGS. 5, 7, and 8, the introduction duct 150 includes a transverse duct portion 151 that is disposed horizontally from the front portion and the upper portion of the belt case 143 in the width direction of the vehicle body, and the transverse duct portion 151. The front and rear duct portions 158 are orthogonal to the right end of the vehicle body and disposed substantially horizontally toward the front side of the vehicle body, and the introduction portion 165 is disposed at the front end of the front and rear duct portion 158.
The transverse duct portion 151 is disposed so as to cross the vehicle body at the rear and upper side of the crankcase 115. As shown in FIG. 5, the rear edge of the transverse duct portion 151 is arranged to be behind the rear edge 115 a of the crankcase 115. Further, around the transverse duct portion 151, a starter motor 131 is arranged on the front side, a luggage box 124 (see FIG. 6) on the upper side, and a rear wheel 118 on the rear side. Therefore, the space in which the transverse duct portion 151 is disposed is, for example, too small for a passage from the air cleaner box 120 to the cylinder assembly 114, but is a suitable size for a passage for cooling the V-belt 142. .

  Further, the transverse duct portion 151 is composed of a plurality of members, here, a plurality of resin molded products so that it can be formed into a shape according to the assemblability and the required function. Specifically, in the transverse duct portion 151, a first transverse duct member 152 and a second transverse duct member 154 are coupled.

As shown in FIGS. 5, 7, and 8, the first transverse duct member 152 is coupled to an opening 133 that opens toward the right side at an upper portion of the belt case 143 via a locking portion 153. The second transverse duct member 154 is coupled to the right end of the first transverse duct member 152 via a locking portion 155. The first transverse duct member 152 and the second transverse duct member 154 are respectively coupled to the crankcase 115 via fixing bolts (not shown) on the lower side. At this time, the first transverse duct member 152 is coupled to the crankcase 115 with a gap between the lower surface of the first transverse duct member 152 and the rear upper surface of the crankcase 115. Therefore, the surrounding air radiated from the starter motor 131 disposed on the front side of the first transverse duct member 152 can be discharged to the rear side through this gap.
Further, since the first transverse duct member 152 and the second transverse duct member 154 are integrally coupled with the crankcase 115, that is, the power unit 113 as described above, the first pivot shaft 110 and the first pivot shaft 110 together with the power unit 113 are combined. 2 swings up and down around the pivot shaft 112.

  The cross-sectional outer shapes of the first transverse duct member 152 and the second transverse duct member 154 are formed in a flat, substantially rectangular shape whose vertical dimension is shorter than the longitudinal dimension. Moreover, the cross-sectional inner shape is formed in a flat, substantially rectangular shape with a reduced outer shape. The inside of the cross-sectional inner shape becomes a passage through which outside air for cooling the V-belt 142 passes. The passage has a passage cross-sectional area that allows the amount of outside air necessary for cooling the V-belt 142 to flow. Thus, by forming the transverse duct portion 151 in a flat shape, when the transverse duct portion 151 swings up and down together with the power unit 113, the V-belt 142 is cooled without interfering with the luggage box 124 or the like. It is possible to ensure a wide cross-sectional area required for the operation.

  Also, as shown in FIG. 5, the front end of the first transverse duct member 152 is behind the front end of the second transverse duct member 154 so as to avoid interference with the starter motor 131 disposed on the front side. Is located. Further, since the first transverse duct member 152 is positioned at the approximate center in the left-right direction of the vehicle body, the upper side of the first transverse duct member 152 is close to the bottom of the luggage box 124. Therefore, the upper surface of the first transverse duct member 152 is lower than the upper surface of the second transverse duct member 154 so as to avoid interference with the bottom of the luggage box 124 when swinging up and down together with the power unit 113. positioned.

Further, as shown in FIG. 7, at the boundary between the first transverse duct member 152 and the second transverse duct member 154, as shown in FIG. Is formed. The locking projection 156 can be locked with a rear lower fender which is a kind of rear fender. By engaging with the rear lower fender, the first transverse duct member 152, together with the rear lower fender, blocks the splashing of sand and water from the rear wheel 118 to the front side.
Further, the right end of the second transverse duct member 154 is bent so as to be orthogonal to the front side, and the bottom surface of the bent portion is drained to drain the water that has entered from the introduction portion 165 to the outside. A hole 157 is formed (see FIG. 6).

  Next, the front and rear duct portion 158 extends to the front side from the position on the upper right side of the crankcase 115, more precisely, from the position overlapping the cooling air cowling 130 when viewed in plan view as shown in FIG. Are arranged to be. As shown in FIG. 4, the front / rear duct portion 158 extends slightly incline upward toward the front side so as to be substantially parallel to the axis p of the piston. The front end of the front / rear duct portion 158 is integrally provided with an introduction portion 165 formed with an introduction port 167 for taking outside air into the introduction duct 150 from the outside. The introduction portion 165 is attached to the frame cover 126 located outside the vehicle body so that more outside air can be taken in from the outside. The attachment of the introduction part 165 will be described later.

  On the other hand, the front and rear duct portion 158 is made of rubber, and a flexible portion 159 is formed in a part thereof. The flexible portion 159 of the present embodiment has a bellows shape and is coupled to the right end of the second transverse duct member 154 by a band 160. The flexible portion 159 has a function of absorbing relative displacement between the introduction portion 165 coupled to the front side and the transverse duct portion 151 coupled to the rear side. That is, the transverse duct portion 151 swings up and down together with the power unit 113, but the introduction portion 165 does not swing together with the power unit 113 because it is attached to the frame cover 126. Therefore, relative displacement occurs between the transverse duct portion 151 and the introduction portion 165 in accordance with the up and down swing of the power unit 113 that is running. At this time, the flexible portion 159 bends according to the relative displacement between the transverse duct portion 151 and the introduction portion 165, so that the relative displacement between the transverse duct portion 151 and the introduction portion 165 is absorbed. In addition, since the flexible part 159 is a bellows shape, it can be easily bent with a small external force, and since it is made of rubber, it has durability against repeated bending.

  Further, according to the swing of the power unit 113, the right end of the second transverse duct member 154 swings on the swing surface F shown in FIG. At this time, since the flexible portion 159 and the introduction portion 165 are located on the swing surface F, the upper portion and the lower portion of the flexible portion 159 are aligned with the swing of the right end of the second transverse duct member 154. The rocking surfaces F expand and contract with each other. That is, since the flexible portion 159 is not twisted off the swing surface F or sheared in a direction away from the swing surface F, the durability of the flexible portion 159 can be further improved.

  Further, the cross-sectional outer shape of the front and rear duct portion 158 including the flexible portion 159 is formed in a substantially elliptical shape whose left-right dimension (width direction of the vehicle body) is shorter than the vertical dimension. Further, the inner cross-sectional shape is formed in a substantially elliptical shape with a reduced outer shape. The inside of the cross-sectional inner shape becomes a passage through which outside air for cooling the V-belt 142 passes. The passage has a passage cross-sectional area that allows the amount of outside air necessary for cooling the V-belt 142 to flow. In this way, by increasing the vertical dimension of the front and rear duct portion 158, the passage necessary for cooling the V-belt 142 without interfering with the components disposed above the crankcase 115 and the cylinder assembly 114 is provided. A wide cross-sectional area can be secured.

  Next, the introduction portion 165 is attached to the frame cover 126 on the right side and the upper side of the cylinder assembly 114. Further, in a state where the introduction portion 165 is attached to the frame cover 126, the front side and the upper side of the belt case 143 when viewed from the left side in FIG. 3, and the front side of the air intake port 129 of the cooling fan when viewed from the right side of FIG. Located on the upper side. Since this position is the center between the front wheel 108 and the rear wheel 118 and is spaced upward from the traveling surface, it is a clean place where dust, water, etc. wound up by the front wheel 108 and the rear wheel 118 are difficult to reach. It is.

  The introduction part 165 has an introduction box 166 that is integrally coupled to the front end of the front and rear duct part 158 and communicates with the front and rear duct part 158. The introduction box 166 is made of rubber and is formed in an elongated shape along the extending direction of the front / rear duct part 158 from the front end of the front / rear duct part 158. As shown in FIG. 4, the right side of the introduction box 166 has an introduction port 167 for taking in outside air from the outside. A flange 168 is formed on the periphery of the introduction port 167 so as to project outside the introduction box 166. The outer peripheral surface of the flange 168 is gently curved as shown in the plan view of FIG. This curve has a shape that matches the curvature of the inner peripheral surface of the frame cover 126 to be attached. As shown in FIG. 4, a plurality of attachment holes 169 are formed in the flange 168 in order to attach the introduction box 166 to the frame cover 126. In addition, a partition plate 172 that closes a part of the opening is attached to the introduction port 167 in order to adjust the amount of outside air taken in from the outside.

Next, a method for attaching the introduction portion 165 will be described with reference to FIGS. 9 and 10 are perspective views of the state in which the introduction portion is attached to the vehicle body cover, as viewed from the inside and the outside of the vehicle body, respectively.
As shown in FIG. 9, a plurality of mounting shafts 175 project from the inner peripheral surface of the frame cover 126 at positions corresponding to the mounting holes 169 of the introduction box 166. The introduction box 166 is fixed to the frame cover 126 by inserting the attachment shafts 175 into the respective attachment holes 169 of the introduction box 166. The frame cover 126 is coupled to the rear frame 105 using a fixing bolt (not shown). As described above, since the introduction box 166 is attached to the frame cover 126 coupled to the rear frame 105, relative displacement occurs between the introduction box 166 and the transverse duct portion 151 that swings together with the power unit 113.

  Further, as shown in FIG. 10, the frame cover 126 has an opening 176 that communicates with the introduction port 167 in a state where the introduction box 166 is attached. When the introduction box 166 is attached to the frame cover 126, the introduction port 167 is in close contact with the opening 176 of the frame cover 126. Accordingly, the introduction port 167 can take in outside air sucked from the opening 176 of the frame cover 126 without leaking. In FIG. 10, the partition plate 172 attached to the rear side of the introduction port 167 can be visually recognized from the opening 176 of the frame cover 126.

  An operation for cooling the V-belt using the cooling structure configured as described above will be described. First, since the fan 134 arranged in the belt case 143 rotates, the inside of the belt case 143 becomes negative pressure. Therefore, the introduction part 165 arranged on the right side of the vehicle body is cleaned from the introduction port 167 with clean outside air. Capture. The outside air taken in from the introduction port 167 is sent from the introduction box 166 along the front and rear duct portions 158 to the rear side of the vehicle body. Thereafter, the outside air is sent along the transverse duct portion 151 to the left side of the vehicle body, and then introduced into the belt case 143 from above the belt case 143 disposed on the left side of the vehicle body. The outside air introduced into the belt case 143 cools the V-belt 142 and is then discharged outside through a discharge hole 149 formed on the left side surface of the belt case 143.

  Thus, according to this embodiment, in order to cool the V-belt 142, the belt-type automatic transmission in which the introduction portion 165 of the introduction duct 150 for introducing outside air is arranged on one side in the left-right direction of the vehicle body. Since it is fixed to the frame cover 126 located on the other side of the machine 117, outside air can be introduced from a clean place. Therefore, since dust and water are not sucked into the belt case 143, the belt type automatic transmission 117 can always be operated satisfactorily without using an air cleaner or the like.

  In the present embodiment, the case where the introduction portion 165 for introducing outside air is attached to the frame cover 126 as a vehicle body cover has been described. It is also possible to do. In this embodiment, the belt type automatic transmission 117 is disposed on the left side of the vehicle body, and the introduction port 167 of the introduction duct 150 is disposed on the right side of the vehicle body. It may be arranged on the right side of the vehicle body, and the introduction port 167 of the introduction duct 150 may be arranged on the left side of the vehicle body.

  100: Motorcycle 101: Steering head pipe 102: Down tube 103: Under frame 104: Main frame 105: Rear frame 110: First pivot shaft 112: Second pivot shaft 113: Power unit 114: Cylinder assembly 115: Crank case 116: Engine 117: Belt-type automatic transmission 118: Rear wheel 120: Air cleaner box 121: Seat 124: Luggage box 125: Front leg shield 126: Frame cover 127: Front fender 128: Rear fender 131: Starter motor 140: Drive Pulley 141: Driven pulley 142: V belt 143: Belt case 144: Crankshaft 147: Mission mechanism 148: Rear Shaft 149: Discharge hole 150: Cooling duct 151: Transverse duct part 152: First transverse duct member 154: Second transverse duct member 158: Front and rear duct part 159: Flexible part 160: Band 165: Introduction part 167: Introduction Port 168: Flange 172: Partition plate

Claims (5)

An engine in which a cylinder assembly is extended forwardly from a crankcase and a belt-type automatic transmission that extends from one side to the rear side in the left-right direction of the engine and transmits power to a rear wheel are integrally configured. In a scooter type motorcycle supported so as to be swingable up and down with respect to the vehicle body,
A belt-type automatic transmission characterized in that an introduction port of an introduction duct for introducing outside air into a belt case of the belt-type automatic transmission is fixed to a vehicle body part located on the other side in the left-right direction. Cooling structure.   The cooling structure for a belt-type automatic transmission according to claim 1, wherein the introduction port is disposed on the front side of the vehicle body with respect to the belt-type automatic transmission.   The cooling structure for a belt-type automatic transmission according to claim 1, wherein a flexible portion is formed in a part of the introduction duct.   4. The cooling structure for a belt-type automatic transmission according to claim 3, wherein the flexible portion is formed along a longitudinal direction of the vehicle body. The introduction duct is
A transverse duct portion coupled to the belt case and disposed along the left-right direction of the vehicle body;
Front and rear duct parts coupled to the transverse duct part and extending toward the front side of the vehicle body,
The belt-type automatic transmission according to any one of claims 1 to 4, further comprising: an introduction portion that is coupled to a front end of the front and rear duct portions and has an introduction port that opens to an outside of a vehicle body. Machine cooling structure.

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