JP3532885B2 - Motorcycle unit swing engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a unit swing engine for a motorcycle, which is integrated with an engine and a transmission case and is supported on a vehicle body so as to be swingable up and down. is there. 2. Description of the Related Art A small motorcycle has, for example, an engine and a transmission case, and one end of the transmission case supports an engine crankshaft and the other end supports a rear wheel axle. This crankshaft and axle are housed in a transmission case so as to be linked by a power transmission mechanism, the engine and the transmission case are integrated, and this is pivotally attached to the vehicle body so that it can swing up and down to form a part of the suspension system. Some use a unit swing engine configured as described above.
No. 0 publication. In the prior art, a cooling air introduction duct is formed by a transmission case cover (“the left transmission case” in the above-mentioned publication) and a soundproof cover (“a case cover” in the above-mentioned publication), and the cooling air is introduced. The cooling air introduced into the introduction duct is introduced into the transmission case from a window (“inlet” in the above-mentioned publication) of the transmission case cover via a filter (“element” in the above-mentioned publication). Although the filter is supported by a support plate and attached to the outer surface of the transmission case cover, the support of the filter is not stable. In order to stably fix the filter, it is required to simplify the fixing mechanism and the mounting operation. The support shaft, which is the intermediate shaft of the starting device, is fitted and fixed in the hole of the transmission case cover. However, it is required to simplify the fitting and fixing mechanism and the fitting and fixing operation. The present invention simplifies the mechanism for fixing the filter to the transmission case cover, simplifies the mounting operation, and fixes the support shaft, which is the intermediate shaft of the starting device, to the transmission case cover. It is an object of the present invention to devise a mechanism for fixing the filter and a mechanism for fixing the intermediate shaft (support shaft) of the starting device to the transmission case cover so that the mechanism and the mounting operation can be simplified. Means taken to solve the above problem is to provide an engine and a transmission case, and to link the crankshaft of the engine and the axle of the rear wheel to the transmission case. Assemble the power transmission mechanism and cover it with the transmission case cover
At the same time, the entire transmission case cover is covered with a soundproof cover.
Cover, the support shaft of the driven gear for driving the crankshaft by the gear of the kick shaft is press-fitted into the transmission case cover and fixed, the engine and the transmission case are integrated, and the vehicle is vertically rocked. Given the unit swing engine of a motorcycle that is freely supported, the following (a) and (b)
It is composed of (B) The transmission case cover and the soundproof cover provide an external space.
Constitutes an air passage for introducing the air, the window portion of the transmission case cover for introducing the external air into the transmission case, a filter covering the window portion, a window cap that holds the filter, the Place a cap with a window in the air passage
You have location, (ii) the by causing screwed a screw in the tapped hole of the support shaft end surfaces, it is made to sandwich the filter in the transmission case cover and the cap. [0006] One end of the support shaft is press-fitted and fixed to the transmission case cover, the filter is sandwiched between the transmission case cover and the cap, and screws are screwed from the outside of the cap into the screw holes in the end surface of the support shaft. , The filter is strongly clamped between the transmission case cover and the cap, and is firmly fixed. Therefore, the fixing mechanism of the filter is simple, and the fixing operation is also simple because the cap is only fixed with one screw. Further, by strongly tightening the screw, one end of the support shaft is firmly fixed to the transmission case cover. The fitting and fixing mechanism of the support shaft to the transmission case cover is such that the support shaft end is press-fitted and fixed to the transmission case cover, and the screw is screwed into a screw hole at the shaft end and tightened. It is mechanically simpler than a fixing mechanism such as screwing or welding of the shaft, and its mounting operation is also simple. An embodiment of the present invention will be described below with reference to the accompanying drawings. A front cover 3 is provided below the handlebar 2 of the motorcycle 1, and a front wheel 5 is provided below the handlebar 2 via a front fork 4. A footrest 6 is formed behind the front cover 3, and a rear cover 7 is further provided behind the footrest 6. A unit swing engine 8 is mounted below the rear cover 7,
A rear wheel 9 is attached to the rear side. The front end of the unit swing engine 8 is vertically swingably connected via a bracket 10, and the rear end is elastically supported by a cushion unit 11. The unit swing engine 8 includes a forced air-cooled four-cycle single-cylinder engine 12, a transmission case 14 extending rearward from a left side surface of a crankcase 13 of the engine 12, and integrated with the crankcase 13. A left transmission case cover 16 attached to the transmission case 14 with bolts 15 is provided. This transmission case 14
The rear wheel 9 is held on one side of the rear part of the transmission case cover 16, that is, on the right side. The transmission case 14 and the transmission case cover 16 cover a power transmission mechanism 17 that transmits the rotation of the engine 12 to the rear wheel 9. I have. A cylinder block 18 is provided in the crankcase 13, a cylinder head 19 is provided in the cylinder block 18, and a piston 20 is provided in the cylinder block 18 so as to be able to reciprocate. The piston 20 is connected to a crankshaft 22 via a connecting rod 21.
And a fan 24 is fixed to the generator 23. The fan 24 introduces outside air into the engine cover 25 through a cooling air inlet 26 provided in the engine cover 25 to forcibly cool the engine 12. An intake pipe 27 is connected to the cylinder head 19, a carburetor 28 is connected to the intake pipe 27, and an air cleaner 29 is connected to the carburetor 28. An exhaust pipe 30 is connected to the cylinder head 19, and a muffler 31 is connected to the exhaust pipe 30.
The cylinder head 19 has an intake valve 32 and an exhaust valve 33.
The intake valve 32 and the exhaust valve 33 are opened and closed by a valve operating mechanism 35 operated by a camshaft 34. A cam gear 36 has a bolt 37 on the camshaft 34.
The cam gear 36 is connected to a drive gear 39 of the crankshaft 22 via a cam chain 38, and the camshaft 34 rotates when the crankshaft 22 is driven. A cam chamber 40 is formed in the cylinder head 19, a pipe 42 is connected to the cylinder head 19 by a joint 41, and engine oil is supplied by driving an oil pump. This engine oil is supplied to the camshaft 34
While lubricating the valve train 35 from the oil passage 43, the engine oil stored in the cam chamber 40 is guided to the cam chain chamber 44, and further circulated from the cam chain chamber 44 to the crank chamber 45. The cylinder head 19 is provided with a cap 46 facing the cam gear 36, and the cab 46 is connected to the air cleaner 29 via a pipe 47. Inside the cap 46, a large-diameter plate 48 having a hole and a small-diameter plate 49 are fastened and fixed with bolts 50, and only unburned gas contained in engine oil is returned to the air cleaner 29 via the pipe 47, and again. It is supplied to the engine 12. The cylinder head 19 has an intake valve 3.
Windows 51 and 52 are formed at positions facing the exhaust valve 33 and the exhaust valve 33, and the intake valves 32, the exhaust valve 33, and the valve train 35 are assembled and adjusted through the windows 51 and 52. The windows 51 and 52 are closed by lids 53 and 54. At the left end of the crankshaft 22, a drive pulley 56 of a V-belt automatic transmission 55 is mounted. The drive pulley 56 includes a movable pulley half 56 a sliding on the crankshaft 22, and a fixed pulley half 56 b opposed to the movable pulley half 56 a and fixed to an end of the crankshaft 22. The movable pulley half 56a is pressed by the roller 57 toward the fixed pulley half 56b with a pressing force corresponding to the rotation speed, and the movable pulley half 56a and the fixed pulley half 5
The belt winding radius of the V-belt 58 wound between 6b changes depending on the increase or decrease of the rotation speed. The transmission case cover 16 is provided with a kick-type starting device 59. The kick-type starting device 59 includes a fixed meshing gear 60 fixed to the end of the crankshaft 22, and a transmission mesh cover 16 opposed thereto. A movable mesh gear 62 slidable in the axial direction on a support shaft 61 fixed by screwing with screws 86 and a helical gear 63 fixed to the movable mesh gear 62; A resistance ring 64 for applying resistance to the rotation of the movable meshing gear 62, a kick shaft 65,
A helical gear 66 fixed to the kick shaft 65 and meshing with the helical gear 63; a kick crank 67 having a kick pedal fixed to extend rearward from the kick shaft 65; And a spring 68 for providing Accordingly, when the kick pedal is depressed, the helical gear 63 is rotated by the helical gear 66, whereby the movable meshing gear 62 moves on the support shaft 61. Thereby, the movable meshing gear 62 engages with the fixed meshing gear 60, and thereafter, the movable meshing gear 62 rotates and the crankshaft 22 is rotated via the fixed meshing gear 60,
The engine 12 can be started. The rotational force of the driving pulley 56 is
8, driven pulley 70, centrifugal clutch 71, driven shaft 72,
The power is transmitted to the rear wheel shaft 74 via the reduction gear mechanism 73. The pulley half 70a of the driven pulley 70 is fixed to the support cylinder 75, and the pulley half 70b is provided on the support cylinder 75 so as to be movable in the axial direction. The belt winding radius of the driven pulley 70 changes. The support cylinder 75 is rotatably supported by the driven shaft 72, and transmits the rotation of the driven pulley 70 to the driven shaft 72 by the centrifugal clutch 71. The transmission case cover 16 has a soundproof cover 77.
The soundproof cover 77 has a shape conforming to the shape of the outer surface of the transmission case cover 16, and its peripheral wall 77 a is bent inward to cover the entire outer surface of the outer wall portion 16 a of the transmission case cover 16. Covering. The soundproof cover 77 is formed of, for example, a synthetic resin, and its peripheral wall 77a is fixed to the peripheral wall 16b of the transmission case cover 16 by screwing a fastening screw 79 with an annular cushion member 78 interposed therebetween. Has been In this way, the soundproof cover 77 covers the entire outer surface of the outer wall 16a of the transmission case cover 16, and the transmission case cover 1
It is possible to reduce the vibration noise generated by the vibration of the vehicle 6 and the like leaking to the outside of the vehicle. The soundproof cover 77 is made of a synthetic resin, but is not limited to this, and may be made of a metal such as a light alloy. The transmission case cover 16 has a part of a peripheral wall 16b on the front side in the vehicle traveling direction extending outward, and an air introduction window 80 formed in the extension 16c.
The entire transmission case cover 16 including the soundproof cover 7c
Covered with 7. The soundproof cover 77 is opposed to a portion 77b that covers the extension 16c of the transmission case cover 16,
A rib 25a is formed integrally with the engine cover 25. Further, the extension portion 16c is formed in a tubular shape, and the air introduction window portion 80 is formed.
Are formed at the center of the cylindrical portion 16f.
A rib 16g extends from b and is integrated. Therefore,
Air enters from between the rib 25a and the portion 77b of the soundproof cover 77 that covers the extension 16c of the transmission case cover 16. Further, even when water flows along the transmission case cover 16 during running on rainy weather or the like, the rib 16g extending from the extension 16c is connected to the center of the cylinder 16f.
This prevents the flow of water and prevents the water from entering the inside through the air introduction window 80. The soundproof cover 77 and the transmission case cover 1
6, an air passage 81 is formed to guide the air sucked from the air introduction window 80 into the transmission case 14, and the air flows from the air passage 81 to an air suction portion 82 formed in the transmission case cover 16. It is guided and can be introduced into the transmission case 14 from the air suction portion 82. The air suction portion 82 is connected to the drive pulley 56 of the automatic V-belt transmission 55.
Window 83 formed in the transmission case cover 16 at a position facing the window 83, and an element (filter) covering the window 83
84 and a cap 85 for holding the element 84. The cap 85 is fixed by being pressed into the support shaft (the transmission case cover 16) with a screw 86 and rotatably supporting a driven gear driven by a helical gear 66 of the kick shaft 65. It is fixed by screwing it into a screw hole on the end face of the intermediate shaft 61 of the device and tightening it. This cap 85 has its rib 85a
The ribs 85a, 85 hold the element 84 and hold it between the transmission case cover.
a is formed between the windows 85b.
From the transmission case cover 1 through the element 84
6 through the window 83. Openings 16d and 16e are formed at the rear of the peripheral wall 16b of the transmission case cover 16. The openings 16d and 16e allow an air discharge passage 87 formed by the transmission case cover 16 and the soundproof cover 77 to communicate with the outside. Can be discharged to The air guided from the air discharge passage 87 is discharged to the outside from an opening 88 of the soundproof cover 77 where the cushion member 78 is not provided. As described above, a part of the peripheral wall 16b of the transmission case cover 16 is extended outward, the air introduction window 80 is formed in the extension I6c, and the transmission case cover including the extension 16c is formed. 16 is covered with a soundproof cover 77, and a cushion member 78 is interposed between a peripheral wall 77 b of the soundproof cover 77 and a peripheral wall 16 b of the transmission case cover 16.
Since the cushion member 78 is not cut off by forming the air introduction window portion 80, the effect of preventing the vibration of the soundproof cover 77 is not impaired. Air is introduced from the air introduction window 80 formed in the extension 16c, and is formed in the transmission case cover 16 through an air passage 81 formed between the soundproof cover 77 and the transmission case cover 16. The air is introduced into the transmission case 14 from the air suction portion 82 thus formed, and the air is introduced into the transmission case 14, so that the accumulation of heat can be reduced. Further, since the air introduction window 80 is covered with the soundproof cover 77 and the extension 16c is formed in a cylindrical shape, the water can be prevented from entering the inside. Further, a support shaft (intermediate shaft of the starting device) 61
The screw 86 screwed into the screw hole on the shaft end face of
Since the support shaft 5 and the support shaft 61 are fixed together by the transmission case cover, their fixing mechanism is simple, and the fixing work thereof is also simple. As described above, according to the present invention, the screw with the window holding the filter is held by screwing the screw into the screw hole of the end face of the support shaft provided in the transmission case cover. Since the filter is screwed to the support shaft and the filter is held between the cap and the transmission case cover, the filter can be firmly fixed between the transmission case cover and the cap by a very simple fixing mechanism, and Even if there is a movement of the support shaft press-fitted and fixed to the transmission case cover, there is a special effect that the press-fit is loosened and the support shaft does not fall out of the transmission case cover.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a motorcycle equipped with a unit swing engine. FIG. 2 is a side view of a snit swing engine of the motorcycle. FIG. 3 is a rear view of a unit swing engine of the motorcycle. FIG. 4 is a sectional view of a unit swing engine of the motorcycle. FIG. 5 is a sectional view of an engine portion of a unit swing engine of the motorcycle. FIG. 6 is a sectional view of a main part of a unit swing engine of the motorcycle. FIG. 7 is a side view of a main part of the unit swing engine of the motorcycle with a soundproof cover and a cap removed. FIG. 8 is a plan view of a cap. FIG. 9 is a rear view of the soundproof cover. [Description of Signs] 1 ... motorcycle 8 ... unit swing engine 9 ... rear wheel 12 ... engine 14 ... transmission case 16 ... transmission case cover 16c ... extension portion 17 ... Power transmission mechanism 22 ... Crank shaft 61 ... Support shaft (intermediate shaft) 62 ... Movable meshing gear 65 ... Kick shaft 66 ... Helical gear 74 ... Rear wheel shaft 77 ... Soundproof cover 78 ... Cushion material 80 ... Air introduction window 81 ... Air passage 82 ... Air suction unit 83 ... Window 84 ... Element (filter) 86 ... ·Screw

Claims (1)

(57) [Claims 1] A power transmission mechanism having an engine and a transmission case, and a power transmission mechanism for interlocking a crankshaft of the engine and an axle of a rear wheel is assembled to the transmission case. UTO covered
In both cases, cover the entire transmission case cover with a soundproof cover.
A driven shaft for driving the crankshaft with the gear of the kick shaft is press-fitted and fixed to the transmission case cover, and the engine and the transmission case are integrated,
In a unit swing engine of a motorcycle supported on a vehicle body to be able to swing up and down , external air is guided by the transmission case cover and the soundproof cover.
Constitutes an air passage for entering the window portion of the transmission case cover for introducing the external air into the transmission case, a filter covering the window portion, a window cap that holds the filter, with the window Place the cap in the air passage
There, the bis by causing screwed into threaded holes of the support shaft end surfaces, motorcycle unit swing engine, characterized in that you are sandwiched the filter in the transmission case cover and the cap.