JP2869786B2 - Timing belt device for internal combustion engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a timing belt device for an internal combustion engine. 2. Description of the Related Art Conventionally, a timing belt for interlocking a crankshaft supported by an engine body with a camshaft of a valve mechanism and a generator driven by rotation of the crankshaft are located close to the same side of the engine body. An internal combustion engine provided with a tension pulley, an auto tensioner and an idle pulley in a belt chamber for accommodating the timing belt is well known. [0003] By the way, in the above-mentioned prior art, a tension pusher is used for an auto tensioner.
Since the tension spring is provided directly on the support shaft of the wheel, it is difficult to accommodate the tension pulley within a narrow timing belt width, and the support shaft becomes bulky, so that the crankcase becomes large. There is a fear. The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to connect a tension spring to a tension pulley indirectly so that a crankcase can be used. It is an object of the present invention to provide a timing belt device for an internal combustion engine capable of suppressing the increase in size of the engine and keeping the space in the belt chamber substantially within the belt width so as to reduce the size of the internal combustion engine. In order to achieve the above object, a timing belt device for an internal combustion engine according to the present invention is provided with a timing for interlocking a crank shaft supported by an engine body and a cam shaft of a valve mechanism. In an internal combustion engine provided with a belt and a generator driven by rotation of a crankshaft close to the same side of the engine main body, a belt chamber storing the timing belt and a generator chamber storing the generator are continuously connected. hand
A tension pulley, an auto tensioner, and an idler pulley are arranged in the belt chamber , an arm provided with the tension pulley is pivotally supported on a side wall of a crankcase, and a tension spring and an auto spring for elastically biasing this arm are provided. The tensioner and the timing belt
Timing at its substantially inside the back of the outline of the generator in the width
Characterized in that it is housed around a belt pulley . FIG. 1 to FIG. 7 are views showing a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a motorcycle, a so-called diamond type is used for a vehicle body frame 2, and a front fork 4 is supported on a head pipe 3 of the vehicle body frame 2 so as to be pivotable. , A front wheel 5 is provided, and an upper portion is provided with a handle 6. Main frame 7 extending backward from head pipe 3
Is provided with a fuel tank 8, a sheet 10 extending rearward from the rear end of the main frame 7 is provided with a sheet 10, and a bracket 11 at a lower end of the main frame 7 is provided with a rear arm 12. , The rear wheel 13 is supported. An internal combustion engine 15 is suspended from a main frame 7, a down tube 14, and a bracket 11 constituting the vehicle body frame 2 via mounts 7a, 14a, 11a. The internal combustion engine 15 uses a V-type two-cylinder, employs a four-cycle air-cooled OHC valve mechanism, and makes the crankshaft 16 perpendicular to the running direction so that the front-side cylinder 17 is directed substantially forward. The rear cylinder 18 is mounted substantially upright. A carburetor 19 is connected to the upper side of the front cylinder 17 and the rear side of the rear cylinder 18, and an exhaust pipe is provided from the lower side of the front cylinder 17 and the front side of the rear cylinder 18. 20 extends from below to the rear of the vehicle body. A crank case 21 of the internal combustion engine 15 is formed so as to be divided into right and left. As shown in FIG. 3, a main shaft 23, a drive shaft 24 and the like of a transmission 22 are supported in addition to the crank shaft 16. A one-way clutch 25 is attached to the crankshaft 16, and a gear 25a of the one-way clutch 25 meshes with a gear 27a of a cell motor 27 via an idle gear 26. Reduction gear 2 attached to crankshaft 16
8 is loosely engaged with the main shaft 23 and meshes with the reduction gear 29, and the power transmitted to the reduction gear 29 is intermittently connected to the main shaft 23 by the clutch 30. A gear 31 is provided on the main shaft 23 and meshes with a gear 32a of an oil pump 32. The clutch 30, the oil pump 32, the oil filter 33 and the like are compactly arranged on one of the crankcases 21. The power of the main shaft 23 of the transmission 22 is transmitted to the drive shaft 24 by a dog clutch operated by a shift fork (not shown), and from a driving sprocket 35 fixed to the drive shaft 24 via a drive chain 36. Sprocket 3 of the rear wheel 13
7 is transmitted. The crankcase 21 on the side where the reduction gear 28 and the reduction gear 29 of the power transmission system are provided has an insert.
The crankshaft 16, the main shaft 23, and the drive shaft 24 are supported via a shaft 38. The insert 38 is integrally cast when it is formed on the crankcase 21. The insert 38 is a member having the same coefficient of thermal expansion as the reduction gear 28 and the reduction gear 29, for example, an iron-based casting. , Formed by forgings. Insert 38 is crankcased by heat change.
The change in the distance between the shafts of the gears 21 is prevented, the change in the backlash between the reduction gear 28 and the reduction gear 29 and between the gears of the transmission 22 is reduced, and the increase in the gear operating noise is suppressed. [0010] As shown in FIG.
Each of the pistons 42 includes a cylinder body 39, a cylinder head 40, a head cover 41, and the like, and is reciprocally fitted to the cylinder body 39. Each of the pistons 42 is connected to the crankshaft 16 via a connecting rod 43. A cam shaft 44 of a valve mechanism is supported on the head cover 41, and pulleys 4 are provided on the left ends of the cam shaft 44 and the crank shaft 16, respectively.
5 and 46 are attached, and the peripheral movement of the timing belt 47 wound around these pulleys 45 and 46 causes the crankshaft 1 to rotate.
6 is transmitted to the camshaft 44 and the cam 4
At 4a, an intake / exhaust valve (not shown) is opened and closed at a predetermined timing. The idle pulleys 48 and 49 and the tension pulley 50 abut on the timing belt 47, and the circumferential path is regulated. These idle pulleys 48, 49 are supported on the side wall 21a of the crankcase 21 by bolts 51, 52, and the tension pulley 50 is supported on the tip of an arm 53. The arm 53 has a base 53a having a spring shaft 5
4, the timing belt 4 is supported by the side wall 21a.
7 is rotatable. One end of the tension spring 55 around which the base 53a of the arm 53 is wound is fixed to the arm 53 with a screw 53b, and the other end is an idler.
The tension pulley 50 provided on the arm 53 is always urged in the direction of the arrow by being in contact with the bolt 52 of the reel 49 to eliminate the slack of the timing belt 47. Arm 53
An auto tensioner 56 further supported by the side wall 21a is connected to the projection 53c, and the timing belt 47 is adjusted to a predetermined strength. The spring shaft 54, the tension spring 55, and the auto tensioner 56 are accommodated in the back of the outline of a generator 57 described later and substantially inside thereof (see FIG. 8). A rotor 58a constituting a rotor side of a generator 57 is further rotatably supported on the outside of the pulley 46 on the crankshaft 16, and the generator 57 and the timing belt 47 are connected to the engine body. Are arranged on the same side. A coil 58b constituting the stator side of the generator 57 is supported inside an outer cover 62, which will be described later. Further, the outer cover 62 is provided with a pickup coil 58c for obtaining an ignition signal of the internal combustion engine. ing. An inner cover 59 is provided inside the timing belt 47 so as to face the cylinders 17 and 18, and a three-part outer cover 6 including the cover of the generator 57 is provided outside.
The inner cover 59, the outer covers 60, 61, 62 and the side wall 21a of the crankcase 21 accommodate a belt chamber 63a for accommodating the timing belt 47 and a generator 57. The generator room 63b communicates with the generator room 63b. As shown in FIGS. 4 and 6, the inner cover 59 has a cover portion 59a facing the front cylinder 17 and a cover portion 5 facing the rear cylinder 18.
9b are connected by a connecting portion 59c. Cover part 59
a, a cam shaft mounting hole 59d, an idler mounting hole 59
e and the outside air intake 70 are formed.
9b is provided with a cam shaft mounting hole 59f and an exhaust port 71, a connecting portion 59c is provided with an idler mounting hole 59g, and the mounting portions 59a and 59b are further provided with mounting holes 59h and positioning protrusions 59i. Are formed. As shown in FIG. 5, fins 59j and 59k are formed outside the cover portions 59a and 59b of the inner cover 59. In the orthogonal direction, the fins 59k are formed along the traveling direction so as to send the traveling wind backward. As shown in FIGS. 5 and 7, fins 60b and 61b are also formed on the outer covers 60 and 61, and both of the fins 60b and 61b are formed along the traveling direction so as to send the traveling wind backward. ing. As shown in FIGS. 3 and 5, the inner cover 59 has the camshaft mounting holes 59d and 5f formed with the head cover 41.
The idler mounting holes 59e and 59g are inserted into the bosses of the side wall 21a of the crankcase 21 through the grommet 66 having a high heat insulating effect, and are inserted into the recesses (not shown) of the side wall 21a of the crankcase 21. The positioning protrusion 59i is engaged, and the tightening screw 65a is inserted into the mounting hole 59h to tighten and fix. Further, as shown in FIG.
A seal packing 67a having a similarly high heat insulating effect is provided on the side of the first seal.
And is fastened and fixed by a fastening bolt 65b. Outer covers 60 and 61 are inner cover 5 respectively.
9 is joined to the cover portions 59a and 59b via a seal packing 67b, and is fixedly fastened by tightening bolts 65c. The mounting portion 62a of the outer cover 62 is joined to and fixed to a rib 21b formed on the side wall 21a of the crank case 21, and the flange portions 62b and 62c of the outer cover 62 are Ends 60 of covers 60 and 61
a, 61a via a seal packing 64. The inner cover 59 and the outer covers 60, 61, 62 are made of, for example, aluminum having a high heat radiation effect. The belt chamber 63a and the generator chamber 63b are provided with predetermined gaps 68, 69 as heat insulating layers between the cylinders 17, 18 of the engine body by the inner cover 59, so that heat from the cylinders 17, 18 can be obtained. Suppress transmission. The gaps 68 and 69 serve as passages for traveling wind, and the cylinder 1
7, 18 and the inner cover 59 are cooled. From the front-side gap 68, the rear-side gap 69 is larger than the cylinder 17,
The gap is increased by 18 so that it can be actively taken into the rear side where traveling wind is difficult to hit. Further, an air cleaner 72 is provided at an outside air inlet 70 formed at a cover portion 59a of the inner cover 59, and a cam shaft 44 is provided near an exhaust port 71 formed at the cover portion 59b. , An exhaust fan 73 is provided. The exhaust fan 73 includes a camshaft 44 and a shaft member 44b.
The cam shaft 44 and the pulley 45 are provided so as to be able to rotate integrally with the cam shaft 44, and are disposed in an exhaust chamber 73b formed by an exhaust cover 73a. By the operation of the exhaust fan 73, air is introduced into the exhaust chamber 73b, and is exhausted from the exhaust port 71 to the gap 69 side. As described above, the arm 53 provided with the tension pulley 50 is pivotally supported on the side wall 21 a of the crankcase 21, and the arm 53 is elastically urged by the tension spring 55. So, tension spring 5
5, the tension pulley 50 does not become bulky, and the space of the belt chamber 63a can be accommodated substantially in the width of the belt 47, so that the internal combustion engine is downsized as a whole. In addition, the tension spring 55 and the
The tensioner 56 is housed substantially behind the outline of the generator 57, so that these parts can be housed without increasing the size of the crankcase 21 and the size of the internal combustion engine is also suppressed. can do. 8 to 12 show a second embodiment. The inner cover 59 of this embodiment is, as shown in FIG.
Cover portions 59a, 59b facing cylinders 17, 18
And a cover facing the side wall 21a of the crankcase 21.
The part 59i is formed integrally. The inner cover 59 is engaged with the positioning projection 59k of the cover portion 59i by engaging with a concave portion (not shown) of the side wall 21a of the crankcase 21, and inserting the tightening screw 65a into the mounting hole 59h for tightening. Fixed. The inner cover 59 is connected to the outer covers 60, 61,
The belt chamber 63a and the generator chamber 63 are tightened and fixed.
b are formed to communicate with each other. The inner cover 59 further includes a cover portion 59i and a side wall 21a of the crankcase 21.
A gap 76 is also formed between the timing belt 47 and the heat insulating layer to block heat transfer from the engine body.
And the transmission of heat to the generator 57 is further suppressed. In this embodiment, the timing belt device has substantially the same configuration as that of the first embodiment. FIGS. 13 and 14 show a third embodiment. In this embodiment, an outside air inlet 77 is also formed in a cover portion 59i of the inner cover 59 of the second embodiment, and an air cleaner 78 is provided in this outside air inlet 77. Therefore, air is more appropriately introduced into the belt chamber 63a and the generator chamber 63b, and cooling is performed more efficiently.
The timing belt device of this embodiment has substantially the same configuration as that of the first embodiment. FIGS. 15 and 16 show a fourth embodiment. This embodiment is applied to a parallel two-cylinder internal combustion engine 15, and a belt chamber 63a and a generator chamber 63b are formed by an inner cover 59 and an outer cover 60. The inner cover 59 is formed so as to face the cylinder 79. The inner cover 59 is inserted into the projection of the head cover 41, and the side of the head cover 41 and the crankcase 2
As in the first embodiment, fastening screws 65a,
It is tightened and fixed at 65b. Outer cover 60 is inner cover 59
And a cover portion 60d for covering the generator 57 provided on the crankshaft 16 are integrally formed with the inner cover 59 and the side wall 21 of the crankcase 21.
a is tightened and fixed with a tightening bolt 65c. An outside air inlet 84 is formed in the side wall 21 a of the crankcase 21, air is introduced through an air cleaner 72, and is discharged from the exhaust port 71 by the operation of an exhaust fan 73 provided on the cam shaft 44. Is done. The timing belt device of this embodiment has substantially the same configuration as that of the first embodiment. [0029] According to the present invention has been described in detail above, according to the present invention, timing
Belt room for storing the belt and generator for storing the generator
The belt chamber is formed continuously, and a tension
And the auto tensioner and idler pulley
An arm provided with a tension pulley is pivotally supported on the side wall of the crankcase, and this arm is elastically urged by a tension spring.
The belt tensioner and the generator room are both cooled because the belt tensioner is contained within the width of the timing belt.
Reduce the width of the internal combustion engine in the crankshaft direction
The tension spring and the auto
The tensioner is housed within the width of the timing belt
Because of this, this also
The number of layers can be reduced, the tension pulley does not become bulky, and the space in the belt chamber can be accommodated substantially in the belt width, and the size of the internal combustion engine can be reduced. In addition, the tension spring and the auto tensioner are positioned within the width of the timing belt, substantially behind the outline of the generator and around the periphery of the timing belt pulley.
On the back side of the outline of the generator
Adjust the dead space around the timing belt pulley
It can be used for installing springs and auto tensioners.
Can accommodate these parts without increasing the size of the crankcase , forming a belt room and a generator room.
The existing shape of the crankcase and cylinder
Since there is no need to scrape, it is possible to suppress an increase in the size of the internal combustion engine.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a motorcycle according to a first embodiment of the present invention. FIG. 2 is a side view of the internal combustion engine according to the first embodiment of the present invention. FIG. 3 is a sectional view taken along line III-III of FIG. 2; FIG. 4 is a side view of the internal combustion engine with an outer cover of a belt room and a generator room removed. FIG. 5 is a sectional view taken along line VV of FIG. 4; FIG. 6 is a front view showing an inner cover. FIG. 7 is a front view showing an outer cover. FIG. 8 is a side view of an internal combustion engine without an outer cover according to a second embodiment of the present invention. FIG. 9 is a sectional view taken along line IX-IX of FIG. FIG. 10 is a sectional view taken along line XX of FIG. 8; FIG. 11 is a sectional view taken along the line XI-XI in FIG. 8; FIG. 12 is a front view showing an inner cover. FIG. 13 is an outer cover according to a third embodiment of the present invention.
FIG. 2 is a side view of the internal combustion engine in which is removed. FIG. 14 is a sectional view taken along line XIV-XIV of FIG. FIG. 15 is an outer cover according to a fourth embodiment of the present invention.
FIG. 2 is a side view of the internal combustion engine in which is removed. FIG. 16 is a sectional view taken along the line XVI-XVI in FIG. 15; [Description of Signs] 15 Internal combustion engine 16 Crank shaft 21 Crank case 21a Crank case side wall 44 Cam shaft 47 Timing belt 48, 49 Idler pulley 50 Tension pulley 53 Arm 55 Tension spring 56 Auto tensioner 57 Generator 63a Belt room

Claims (1)

(57) [Claims] An internal combustion engine comprising a timing belt for interlocking a crankshaft supported by an engine body and a camshaft of a valve mechanism and a generator driven by rotation of the crankshaft close to the same side of the engine body. The belt room for storing the belt and the generator room for storing the generator
A tension pulley, an auto tensioner, and an idler pulley are arranged in the belt chamber , an arm provided with the tension pulley is pivotally supported on a side wall of a crankcase, and a tension spring and an auto spring for elastically biasing this arm are provided. The tensioner and the timing belt
Timing at its substantially inside the back of the outline of the generator in the width
A timing belt device for an internal combustion engine, wherein the timing belt device is disposed around a belt pulley .