JP2005105979A - Blow-by gas return structure of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the deformation of an intake tube for connecting a blow-by gas hose thereto in a blow-by gas return structure of an internal combustion engine. <P>SOLUTION: In this blow-by gas return structure of the engine, the engine including an intake device is swingably installed on a vehicle body frame, and a blow-by gas generated in the crankcase of the engine is returned to the intake device 52 through the blow-by gas tube 73. One end of the blow-by gas tube 73 is connected to a blow-by gas discharge port 51a formed on the cylinder head 48 side of the engine, the other end thereof is connected to a connecting tube (62) installed on the engine of the air cleaner case 61 through a joint member 76, and the joint member 76 is fitted to the air cleaner case 61. Thus, the connecting tube 62 can be prevented from being deformed by the displacement of the blow-by gas tube 73. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a blow-by gas reduction structure for an internal combustion engine.

As a conventional blow-by gas reduction structure for an internal combustion engine, one in which one end of a blow-by gas pipe is connected to an air cleaner hose is known (for example, see Patent Document 1).
Japanese Utility Model Publication No. 61-37414

FIG. 1 of Patent Document 1 will be described with reference to FIG. In addition, the code | symbol was reassigned.
FIG. 11 is an explanatory view showing a blow-by gas reduction structure of a conventional internal combustion engine. A PCV (Visitive Crank) is connected to a head cover 201 provided on the upper part of the internal combustion engine 200 and an air cleaner hose 203 connecting the air cleaner 202 to the internal combustion engine 200 side. (Case ventilation) By connecting the hose 204, blow-by gas generated in the crankcase 206 of the internal combustion engine 200 is sent from the head cover 201 to the air cleaner hose 203 via the PCV hose 204, and the internal combustion engine is passed through the intake manifold 207 from the air cleaner hose 203. Returning to the combustion chamber of the engine 200 is shown. Reference numeral 211 denotes an auxiliary hose having one end connected to the PCV hose 204 via an oil reservoir 212 and a one-way valve 213, and the other end connected to the crankcase 206 to thereby separate the oil content separated in the PCV hose 204. This is an auxiliary hose that collects

  In the above technique, in order to connect the end portion of the PCV hose 204 to the air cleaner hose 203, when the air cleaner hose 203 has flexibility such as rubber, the PCV hose 204 is caused by engine vibration or the like. When it swings, the air cleaner hose 203 swings with this swing. Since the oil reservoir 212, the one-way valve 213, and the auxiliary hose 211 are connected to the PCV hose 204, the air cleaner hose 203 is more easily deformed by the weight of the oil reservoir 212, the one-way valve 213, and the auxiliary hose 211. .

  If the air cleaner hose 203 is deformed, the amount of air supplied to the internal combustion engine 200 through the air cleaner hose 203 may change.

  The subject of this invention is suppressing the deformation | transformation of the intake pipe which connects a blow-by hose in the blow-by gas reduction structure of an internal combustion engine.

  The invention according to claim 1 is a blow-by gas reduction structure for an internal combustion engine in which an internal combustion engine including an intake device is swingably attached to a vehicle body frame, and blow-by gas generated in a crankcase of the internal combustion engine is returned to the intake device by blow-by piping. The blow-by gas pipe has one end connected to a blow-by gas discharge port provided on the internal combustion engine side and the other end connected to the intake pipe of the air cleaner case via a joint, and the joint is attached to the air cleaner case. Features.

  The joint is connected to the intake pipe via a joint, and the joint is attached to the air cleaner case to prevent the intake pipe from being deformed by the displacement of the blow-by piping due to the swinging, vibration, etc. of the internal combustion engine.

  The invention according to claim 2 is provided with an air passage for guiding air from the air cleaner case to the crankcase of the internal combustion engine in order to increase the amount of blow-by gas reduction to the intake device, and the blow-by piping is curved upwardly. It is characterized by.

  Even if a large amount of oil and moisture adheres to the inside of the blow-by piping when an air passage is provided to increase the amount of blow-by reduction to the intake device, the blow-by piping is curved upward and the oil in the blow-by piping Return the minute and moisture into the crankcase.

  According to a third aspect of the present invention, the guide member provided on the vehicle body frame side is arranged such that the blow-by gas discharge port side and the intake pipe are distributed in the front-rear direction of the vehicle with respect to the swing shaft for mounting the internal combustion engine on the vehicle body frame side. The middle part of the blow-by piping is guided by.

  When the internal combustion engine and the intake pipe swing together with respect to the swing axis, the curved blow-by pipe moves in an arc shape, reducing the displacement in the direction perpendicular to the blow-by pipe, and making the blow-by pipe impossible with the guide member I will guide you.

According to a fourth aspect of the present invention, an internal combustion engine is swingably attached to a lower portion of a vehicle body frame, a storage container is attached to an upper portion of the vehicle body frame, and an internal combustion engine is interposed between the internal combustion engine and an intake device that supplies air to the internal combustion engine. In a vehicle provided with blow-by piping that returns blow-by gas generated in the crankcase of the engine to the intake device, the blow-by piping is disposed between the internal combustion engine and the storage container, and one end of the blow-by piping is disposed on the cylinder head side of the internal combustion engine. Connect to the blow-by gas discharge port provided, connect the other end to an intake pipe provided on the internal combustion engine side of the intake device via a joint, and attach this joint to a connection support member provided in the intake device, and blow-by piping The center of curvature is provided in the vicinity of the swing shaft for mounting the internal combustion engine on the body frame side, and the blow-by piping is a guide member in the tangential direction. It is characterized in that so as to guide.
When the internal combustion engine swings with respect to the vehicle body frame, the blow-by piping can be smoothly and smoothly guided by the guide member.

The invention according to claim 5 is characterized in that the connection support member is an air cleaner case.
By using an air cleaner case as the connection support member, there is no need to provide a special connection support member.

  In the invention according to claim 1, since the blow-by gas pipe is connected to the intake pipe via a joint, and this joint is attached to the air cleaner case, even if the blow-by pipe is displaced due to the oscillation or vibration of the internal combustion engine, this displacement Can be suppressed by the air cleaner case through the joint, and the intake pipe can be prevented from being deformed.

  In the invention according to claim 2, since the air passage for guiding air from the air cleaner case to the crankcase of the internal combustion engine is provided and the blow-by piping is curved upward, the air passage is provided to provide a blow-by reduction amount to the intake device. Even if a large amount of oil and moisture adheres to the inside of the blow-by piping when it is increased, the oil and moisture in the blow-by piping is returned to the crankcase by curving the blow-by piping upward. Thus, for example, the air cleaner element in the air cleaner case can be prevented from being soiled with oil and moisture, and the replacement time of the air cleaner element can be extended.

  In the invention according to claim 3, the guide member provided on the vehicle body frame side in which the blow-by gas discharge port side and the intake pipe are arranged in the vehicle front-rear direction with respect to the swing shaft for mounting the internal combustion engine on the vehicle body frame side. Since the middle part of the blow-by pipe is guided in this way, when the internal combustion engine and the intake pipe swing together with respect to the swing axis, the curved blow-by pipe moves in an arc shape. The displacement can be reduced, and the blow-by piping can be guided without difficulty by the guide member. Therefore, bending and crushing of the blow-by piping can be suppressed, the amount of blow-by gas reduction can be increased, and the layout of the blow-by piping can be easily performed.

  In the invention according to claim 4, the blow-by piping is disposed between the internal combustion engine and the storage container, one end of the blow-by piping is connected to the blow-by gas discharge port, and the other end is connected to the intake pipe via a joint, This joint is attached to the connection support member, the center of curvature of the blow-by piping is provided in the vicinity of the swing shaft for mounting the internal combustion engine on the vehicle body frame side, and the blow-by piping is guided by the guide member in the tangential direction. When the internal combustion engine swings with respect to the frame, the blow-by piping moves around the swing axis close to the center of curvature. Therefore, the displacement in the direction perpendicular to the blow-by piping can be reduced, and the blow-by piping is guided. It can be smoothly guided by the members. Therefore, since the bending or crushing of the blow-by piping can be suppressed, the flow of blow-by gas in the blow-by piping becomes smooth, and blow-by reduction can be performed efficiently.

  In the invention which concerns on Claim 5, since the connection part support member was made into the air cleaner case, it is not necessary to provide a connection part support member specially, a number of parts can be reduced and cost can be reduced.

The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.
FIG. 1 is a side view of a vehicle according to the present invention. A vehicle 10 includes a vehicle body frame 11 having a front frame 12 and bolts 13... The power unit 17 (an engine 18 as an internal combustion engine) is configured so that the fuel tank 16 is attached to the lower part of the front frame 12 and is substantially horizontal in the vehicle front-rear direction. And a power transmission mechanism 21 connected to the engine 18). The motorcycle is swingably attached via a link 22, and the rear portion of the power unit 17 is attached to the rear portion of the rear frame 14 via a rear cushion unit 23. is there.

  Here, 31 is a head pipe attached to the front frame 12, 32 is a steering shaft rotatably supported by the head pipe 31, 33 is a front fork attached to the lower end of the steering shaft 32, and 34 is a lower end of the front fork 33. The attached front wheel, 36 is a bar handle attached to the upper end of the steering shaft 32, 37 is a front cover that covers the upper part of the front frame 12, 38 is a front fender that covers the front wheel 34, and 41 is disposed above the fuel tank 16. The step floor, 42 is a storage box as a storage container attached to the upper part of the rear frame 14, 43 is a seat provided on the upper part of the storage box 42, and 44 is a body cover that covers the vehicle body below the seat 43.

Reference numeral 45 denotes a rear wheel attached to the rear portion of the power unit 17, 46 denotes a rear fender that covers the upper portion of the rear wheel 45, 47 denotes a cylinder block in which a piston (not shown) is movably accommodated, and 48 denotes a front portion of the cylinder block 47. The attached cylinder head, 51 is a head cover covering the end opening of the cylinder head 48, 52 is an intake device extending from the upper part of the cylinder head 48 to the rear of the vehicle body, 53 is an exhaust device extending from the lower part of the cylinder head 48 to the rear of the vehicle body, and 54 is It is a stand.
The cylinder block 47 and the cylinder head 48 (including the head cover 51) described above are members constituting the internal combustion engine main body 56.

FIG. 2 is a system diagram showing the flow of air, fuel and blow-by gas in the internal combustion engine according to the present invention.
The air flow path is indicated by a double line. That is, the air enters the air cleaner case 61 from the air inlet 61a of the air cleaner case 61 as a connection support member, and flows in two paths, that is, a main path and a sub path. In the main path, air flows from the air cleaner case 61 to the throttle body 63 through the connecting tube 62 as an intake pipe, flows from the throttle body 63 to the cylinder head 48, and reaches the combustion chamber. This main path is configured by the above-described intake device 52 (see FIG. 1), and air moves by intake negative pressure.

  In the sub-path (reference numeral 52A) as an air passage, air flows from the air cleaner case 61 into the crankcase 67 constituting the engine through the solenoid valve 64 and the reed valve 66. That is, the air moves when the inside of the crankcase 67 becomes negative pressure.

  The fuel flow path is indicated by a thick broken line. That is, fuel is pumped from the fuel tank 16 to the injector 71 by the fuel pump 68, injected from the injector 71 into the intake port of the cylinder head 48, reaches the combustion chamber, mixes with air, and burns.

  The flow path of blow-by gas is indicated by a thick solid line. That is, blow-by gas blown into the crankcase 67 from the combustion chamber flows from the crankcase 67 to the cylinder head 48 via the cylinder block 47 and blow-by from a blow-by gas discharge port (details will be described later) provided in the head cover 51. It reaches the connecting tube 62 through the pipe 73.

  The air sub-path 52A described above is configured to send air into the crankcase 67 in order to increase the amount of blow-by gas reduction to the combustion chamber via the blow-by piping 73 and the connecting tube 62. The amount of air sent into the crankcase 67 is adjusted by controlling the opening and closing of the solenoid valve 64 according to the rotational speed.

  FIG. 3 is a plan view of an essential part showing the blow-by gas reduction structure of the internal combustion engine according to the present invention (the arrow (FRONT in the figure indicates the front of the vehicle; the same applies hereinafter)) and the opening of the cylinder head 48 of the engine 18 The head cover 51 is closed, one end of the blow-by pipe 73 is connected to the blow-by gas discharge port 51a provided in the head cover 51, and one end of the suction pipe 75 is connected to the cylinder head 48 so as to communicate with the intake port of the cylinder head 48. The front end of the throttle body 63 is connected to the other end of the suction pipe 75, one end of a rubber connecting tube 62 is connected to the rear part of the throttle body 63, and the air cleaner case 61 is connected to the rear part of the connecting tube 62. And connecting the connecting tube 62 to the air cleaner case 61 The other end of the blow pipe 73 as well as connected via the joint member 76 in the vicinity, indicating that attachment of the joint member 76 to the air cleaner case 61. Reference numeral 78 denotes a fuel pipe for supplying fuel from the fuel tank 16 (see FIG. 1) to the engine 18, and 79 denotes an engine side connection member for connecting the fuel pipe 78 to the cylinder head 48.

  The throttle body 63 has a throttle cable guide 81 attached to the side, and a throttle cable 82 for opening and closing a throttle valve (not shown) attached to the rear of the throttle cable guide 81.

  The throttle cable guide 81 is a member in which a resin harness clamper 83 is attached to a support portion 81 a provided integrally at the front portion, and the wire harness 84 is fixed by the harness clamper 83. Reference numerals 84 a and 84 b are belt members that bind the wire harness 84.

  Thus, by providing the throttle cable guide 81 with the support portion 81a that supports the harness clamper 83, a special support member for supporting the harness clamper 83 becomes unnecessary, and the number of parts can be reduced. Cost and weight can be reduced.

  FIG. 4 is a side view of the main part showing the blow-by gas reduction structure of the internal combustion engine according to the present invention. The blow-by piping 73 is connected to the head cover 51 and the connecting tube 62 (see FIG. 3), and is intermediate from both ends. A rear arc portion 73a having an arc shape is formed at the rear portion of the blow-by pipe 73, and the center of the rear arc portion 73a, that is, the center of the circle including the rear arc portion 73a is formed. The point 85 is arranged in the vicinity of the swing shaft 86 of the link 22 with respect to the rear frame 14 and the swing shaft 87 of the power unit 17 with respect to the link 22 to suppress the swing of the rear arc portion 73a of the blow-by pipe 73 and the rear arc when the power unit 17 swings. A rear subframe 91 in which a guide member 88 for guiding the portion 73 a is attached to the rear frame 14. Indicating that the attachment was. Reference numeral 73 b denotes a front arc portion of the blow-by pipe 73, and 73 c denotes a top part of the blow-by pipe 73.

  FIG. 5 is a plan view showing a blow-by gas pipe connecting portion of the internal combustion engine according to the present invention. The air cleaner case 61 is composed of a case main body 94 and a case cover 95 covering the opening of the case main body 94. The connecting tube 62 is inserted from a mounting hole (not shown) provided in the inner wall 94a, and the fitting portion 62a provided in the intermediate portion of the connecting tube 62 is fitted and fixed in the mounting hole, and the vicinity of the fitting portion 62a. The end of the blow-by piping 73 is connected to the connecting tube 62 via the joint member 76, and the joint member 76 is attached to the attachment seat 94 c provided on the inner wall 94 a of the case main body 94. In addition, 94d is a hose connection part which connects the hose mentioned later.

  The connecting tube 62 includes a hose holding portion 62b that is integrally protruded laterally to hold a first air supply hose 131, which will be described later, and the first air supply is substantially parallel to the connecting tube 62 by the hose holding portion 62b. The hose 131 can be held, the first air supply hose 131 can be brought close to the connecting tube 62, and the size reduction can be achieved. Further, since the hose holding portion 62a is integrally formed with the connecting tube 62, a special member for holding the first air supply hose 131 becomes unnecessary, the number of parts can be reduced, and the cost and weight can be reduced. Can do.

6 (a) and 6 (b) are perspective views showing a blow-by piping connection part according to the present invention, (a) is an enlarged view of part A in FIG. 5, and (b) is a view as seen from the arrow b in (a). is there.
In (a), the joint member 76 includes a base tube 101, two first connection tubes 102 and second connection tubes 103 extending from the base tube 101, and a plate-like mounting portion 104 provided on the base tube 101. The first connecting pipe 102 is inserted into the tube side connecting pipe 62c integrally formed with the connecting tube 62, and the tube side connecting pipe 62c is tightened with the clamp member 106 to be connected to the second connecting pipe 103. The end of the blow-by pipe 73 is fitted and the end of the blow-by pipe 73 is fastened with the clamp member 107, and the plate-like attachment portion 104 is attached to the attachment seat 94 c of the case body 94 with the screw 108.

In (b), the mounting seat 94c of the case main body 94 is a portion in which standing walls 94e, 94e are provided at both ends, and the plate-like mounting portion 104 of the joint member 76 is disposed between the standing walls 94e, 94e. And fix with screws 108.
Therefore, even if the joint member 76 is attached to the case main body 94 with one screw 108, the joint member 76 does not rotate with respect to the case main body 94, and the joint member 76 can be fixed easily and reliably.

  FIG. 7 is a front view showing a guide member for guiding the blow-by piping according to the present invention. The guide member 88 includes a base half body 111 formed in a substantially arc shape and an arc-shaped movable body adapted to the base half body 111. The half body 112 and the vehicle body side mounting portion 113 provided at the bottom of the base half body 111 are integrally formed of resin.

The base half body 111 includes a bulging portion 114 and is a portion in which an engagement hole 116 is provided in the bulging portion 114.
The movable half body 112 is a portion in which an engagement protrusion 118 is projected at one end and a thin wall portion 121 is provided at the other end. In the initial state, the base half body 111 and the movable half body 112 are left and right in the drawing. In this state (the movable half 112 is at the position indicated by the imaginary line), the movable half 112 is bent in the direction of the arrow from this state with respect to the base half 111 at the thin-walled portion 121 and then the base half. A circular guide hole 123 is formed by engaging the engagement protrusion 118 in the engagement hole 116 in accordance with the body 111, and the guide hole 123 prevents and guides the blow-by piping 73.

  The vehicle body side mounting portion 113 is formed in a dish shape so as to be in close contact with the rear subframe 91 (see FIG. 4) and stabilize the guide member 88, and the protruding engagement protruding from the mounting base 125 The projecting engagement portion 126 is a portion that serves as a retaining member when the guide member 88 is attached to the rear subframe 91 by being inserted into an attachment hole provided in the rear subframe 91.

FIG. 8 is a plan view of the main part showing the air passage of the vehicle according to the present invention. One end of the first air supply hose 131 is connected to the hose connection part 94d provided in the case main body 94 of the air cleaner case 61. The other end of the air supply hose 131 is connected to the suction port 64 a provided in the solenoid valve 64, and one end of the second air supply hose 132 is connected to the discharge port 64 b provided in the solenoid valve 64. This shows that the other end is connected to the suction port 66 a of the reed valve 66 attached to the side wall 67 a of the crankcase 67. Reference numerals 134 and 136 denote hose clamps.
The sub route 52A as an air passage is from the hose connecting portion 94d to the reed valve 66.

Next, the operation of the blow-by piping 73 described above will be described.
FIGS. 9A and 9B are first operation diagrams showing the operation of the blow-by piping according to the present invention.
In (a), for example, when the power unit swings clockwise around the swing axis 87 indicated by a white circle in the drawing, the blow-by piping 73 swings integrally with the power unit as indicated by an arrow from the position indicated by the imaginary line. To do.

  Since the rear arc portion 73a of the blow-by piping 73 is provided in the vicinity of the swing shaft 87, the rear arc portion 73a is centered on the swing shaft 87 with the swing of the power unit. Since it moves substantially in the axial direction, the displacement in the direction perpendicular to the axis is small, so that it passes smoothly through the guide hole 123 of the guide member 88. That is, the rear arc portion 73a can be guided by the guide member 88 in the direction of the tangent 73e.

  In (b), when the power unit swings counterclockwise about the swing axis 87, the blow-by piping 73 swings integrally with the power unit as indicated by the arrow from the position indicated by the imaginary line, and in the case of (a) Similarly, the rear arc portion 73a passes smoothly through the guide hole 123 of the guide member 88. That is, the rear arc portion 73a can be guided by the guide member 88 in the direction of the tangential line 73f.

FIG. 10 is a second operation diagram showing the operation of the blow-by piping according to the present invention.
Since the blow-by gas contains oil and moisture, when the blow-by gas flows in the blow-by piping 73 from the head cover side to the connecting tube side, the oil concentration on the inner wall 73d is closer to the head cover side in the front arc portion 73b. Many droplets 141 of water adhere. When the droplet 141 collects and becomes large, its weight flows down to the head cover side as shown by an arrow B and returns to the crankcase.

  Therefore, almost no oil or moisture flows to the connecting tube, and blowby gas from which oil or moisture has been removed flows to the connecting tube as shown by arrow C. Is less likely to adhere to the air, and the intake performance can be improved, and the replacement period of the air cleaner element can be extended.

  As described above with reference to FIGS. 3, 4, and 5, according to the present invention, the engine 18 including the intake device 52 is swingably attached to the vehicle body frame 11, and is generated in the crankcase 67 of the engine 18. In the blow-by gas reduction structure of the engine 18 for returning the blow-by gas returned to the intake device 52 by the blow-by pipe 73, one end of the blow-by gas pipe 73 is connected to a blow-by gas discharge port 51a provided on the cylinder head 48 side of the engine 18, and the like. The end is connected to a connecting tube 62 provided on the engine 18 side of the air cleaner case 61 via a joint member 76, and the connecting member 76 is attached to the air cleaner case 61, so that the connecting tube 62 is deformed by the displacement of the blow-by piping 73. With the feature of preventing That.

  The blow-by gas pipe 73 is connected to the connecting tube 62 via the joint member 76, and the joint member 76 is attached to the air cleaner case 61. Therefore, even if the blow-by pipe 76 is displaced due to the swing and vibration of the engine 18, this displacement Can be suppressed by the air cleaner case 61 via the joint member 76, and the connecting tube 62 can be prevented from being deformed.

  Secondly, as described with reference to FIGS. 4, 8, and 10, the present invention provides a crankcase 67 of the engine 18 from the air cleaner case 61 in order to increase the amount of blowby gas reduction to the intake device 52 (see FIG. 3). A sub-path 52A as an air passage for guiding air is provided, and a blow-by pipe 73 is curved upward.

  When the auxiliary passage 52A for guiding air from the air cleaner case 61 to the crankcase 67 is provided and the blow-by piping 73 is curved upward, the auxiliary passage 52A is provided to increase the amount of blow-by reduction to the intake device 52. Even if much oil and moisture adhere to the inside of the blow-by piping 73, the oil and moisture in the blow-by piping 73 can be returned into the crankcase 67 by curving the blow-by piping 73 upward. For example, the air cleaner element in the air cleaner case 61 can be prevented from being soiled with oil and moisture, and the replacement time of the air cleaner element can be extended.

  Thirdly, as described with reference to FIGS. 3 and 4, the present invention relates the blow-by gas discharge port 51 a side and the connecting tube 62 to the vehicle 10 with respect to the swing shafts 86 and 87 for attaching the engine 18 to the vehicle body frame 11 side. (Refer to FIG. 1) and arranged in the front-rear direction, and the guide member 88 provided on the vehicle body frame 11 side guides the intermediate portion of the blow-by pipe 73.

  The blow-by gas discharge port 51a side and the connecting tube 62 are arranged separately in the front-rear direction of the vehicle 10 with respect to the swing shafts 86 and 87, and an intermediate portion of the blow-by piping 73 is provided by a guide member 88 provided on the vehicle body frame 11 side. Since the guide is guided, when the engine 18 and the connecting tube 62 swing together with respect to the swing shafts 86 and 87, the curved blow-by pipe 73 moves in an arc shape, so that the displacement in the direction perpendicular to the blow-by pipe 73 is displaced. The blow-by piping 73 can be guided without difficulty by the guide member 88. Therefore, bending and crushing of the blow-by piping 73 can be suppressed, the amount of blow-by gas reduction can be increased, and the layout of the blow-by piping 73 can be easily performed.

  In the fourth aspect of the present invention, as described with reference to FIGS. 1, 3, and 4, the engine 18 is swingably attached to the lower portion of the vehicle body frame 11, and the storage box 42 is attached to the upper portion of the vehicle body frame 11. In the vehicle 10 provided with the blow-by piping 73 between the intake device 52 for supplying air to the engine 18, the blow-by piping 73 is disposed between the engine 18 and the storage box 42, and one end of the blow-by piping 73 is connected to the engine 18. The other end is connected to a connecting tube 62 provided on the engine 18 side of the intake device 52 via a joint member 76, and the joint member 76 is connected to the blow-by gas discharge port 51 a provided on the cylinder head 48 side. It is attached to an air cleaner case 61 as a connection support member provided in the device 52, and blow-by arrangement A center point 85, which is the center of curvature of 73, is provided in the vicinity of swing shafts 86, 87 for mounting the engine 18 on the body frame 11 side, and blow-by piping 73 is connected to tangents 73e, 73f (see FIGS. 9A and 9B). The guide member 88 guides it in the direction of).

  A blow-by pipe 73 is disposed between the engine 18 and the storage box 42, and one end of the blow-by pipe 73 is connected to the blow-by gas discharge port 51a, and the other end is connected to the connecting tube 62 via a joint member 76. The joint member 76 is attached to the air cleaner case 61, the center point 85 of the blow-by pipe 73 is provided in the vicinity of the swing shafts 86 and 87 for mounting the engine 18 on the body frame 11 side, and the blow-by pipe 73 is guided by the guide member 88 in the tangential direction. Since the guide 18 is guided, when the engine 18 swings with respect to the vehicle body frame 11, the blow-by pipe 73 moves around the swing shafts 86 and 87 close to the center of curvature, so that the blow-by pipe 73 is orthogonal to the blow-by pipe 73. Directional displacement can be reduced, blow-by piping 3 can be guided smoothly by the guide member 88, the flow of the blow-by gas in the blow pipe 73 becomes smooth, efficient blowby reduction can be performed.

Fifth, the present invention is characterized in that the connection support member is an air cleaner case 61 as described in FIG.
Since the connection portion support member is the air cleaner case 61, it is not necessary to provide the connection portion support member specially, the number of parts can be reduced, and the cost can be reduced.

  In this embodiment, as shown in FIG. 6A, the case main body 94 and the joint member 76 are separated from each other. However, the present invention is not limited to this, and the joint member 76 is integrally formed with the case main body 94. Also good.

  The blow-by gas reduction structure for an internal combustion engine of the present invention is suitable for a motorcycle.

1 is a side view of a vehicle according to the present invention. It is a systematic diagram which shows the flow of the air of the internal combustion engine which concerns on this invention, fuel, and blow-by gas. It is a principal part top view which shows the blowby gas reduction structure of the internal combustion engine which concerns on this invention. It is a principal part side view which shows the blowby gas reduction structure of the internal combustion engine which concerns on this invention. It is a top view which shows the blowby gas piping connection part of the internal combustion engine which concerns on this invention. It is a perspective view which shows the blowby piping connection part which concerns on this invention. It is a front view which shows the guide member which guides the blow-by piping which concerns on this invention. It is a principal part top view which shows the air passage of the vehicle which concerns on this invention. It is the 1st operation view showing an operation of blowby piping concerning the present invention. It is the 2nd operation figure showing an operation of blowby piping concerning the present invention. It is explanatory drawing which shows the blowby gas reduction structure of the conventional internal combustion engine.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Vehicle, 11 ... Body frame, 17 ... Power unit, 18 ... Internal combustion engine (engine), 42 ... Storage container (storage box), 48 ... Cylinder head, 51a ... Blow-by gas discharge port, 52 ... Intake device, 52A ... Deputy Route (air passage), 61 ... Connection portion support member (air cleaner case), 62 ... Intake pipe (connecting tube), 67 ... Crank case, 73 ... Blow-by piping, 76 ... Joint (joint member), 86, 87 ... Swing shaft 88 ... Guide members.

Claims (5)

In the blow-by gas reduction structure of the internal combustion engine, the internal combustion engine including the intake device is swingably attached to the vehicle body frame, and the blow-by gas generated in the crankcase of the internal combustion engine is returned to the intake device by blow-by piping.
One end of the blow-by gas pipe is connected to a blow-by gas discharge port provided on the internal combustion engine side, and the other end is connected to the intake pipe of the air cleaner case by providing a joint, and the joint is held by the air cleaner case. A blowby gas reduction structure for an internal combustion engine.   The air passage for introducing air from an air cleaner case to a crankcase of an internal combustion engine in order to increase the amount of blow-by gas reduction to the intake device, and the blow-by piping is curved upwardly. 2. A blowby gas reduction structure for an internal combustion engine according to 1.   The blow-by gas discharge side and the intake pipe are arranged in the vehicle front-rear direction with respect to a swing shaft for mounting the internal combustion engine on the vehicle body frame side, and an intermediate portion of the blow-by pipe is provided by a guide member provided on the vehicle body frame side. The blow-by gas reduction structure for an internal combustion engine according to claim 1 or 2, wherein the structure is guided. An internal combustion engine is swingably attached to the lower part of the body frame, a storage container is attached to the upper part of the body frame, and is generated in the crankcase of the internal combustion engine between the internal combustion engine and an intake device that supplies air to the internal combustion engine. In a vehicle provided with a blow-by pipe for returning the blow-by gas to the intake device,
The blow-by piping is arranged between the internal combustion engine and the storage container, one end of the blow-by piping is connected to a blow-by gas discharge port provided on the cylinder head side of the internal combustion engine, and the other end is connected to the internal combustion engine of the intake device. Connected to the intake pipe provided on the engine side via a joint, this joint is attached to the connection support member provided on the intake device, the center of curvature of the blow-by piping is near the swing shaft for mounting the internal combustion engine on the body frame side A blow-by gas reduction structure for an internal combustion engine, wherein the blow-by pipe is guided by a guide member in a tangential direction thereof.   The blow-by gas reduction structure for an internal combustion engine according to claim 4, wherein the connection support member is an air cleaner case.

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