JP2008008320A - Power unit transmission case - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide split right and left power unit transmission cases one of which can be easily removed in an enhanced workable manner without requiring a time and labor for removing work. <P>SOLUTION: In a transmission case structure, the split right and left transmission cases 70, 11L store a power transmission device T for a power unit P and the transmission case 70 out of the right and left transmission cases 70, 11L, arranged outside a vehicle body, rotatably journals a driven shaft 50 at its end fitted to a bearing recessed portion 76 via a bearing 35. At right and left outer peripheral edges 71, 61 constituting mutually opposed mating faces of the right and left transmission case 70, 11L, located in approximately vertical symmetry to the driven shaft 50, protruded pieces 77, 67 opposing each other are formed on the right and left transmission cases 70, 11L, respectively. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transmission case that houses a power transmission device of a power unit mounted on a motorcycle.

A power transmission device of a power unit mounted on a motorcycle is configured by an endless belt or chain being bridged between a drive shaft that is rotated by the power of an internal combustion engine and a driven shaft that is linked to a rear wheel. The power of the internal combustion engine is transmitted to the rear wheels for running.
This power transmission device is accommodated in a transmission case.

A transmission case of this type of power unit is normally biased to the left from the internal combustion engine and extends rearward. The transmission case that is long in the front-rear direction is divided into left and right parts.
Patent Document 1 discloses a transmission case having such a structure, and the disclosed transmission case has mating surfaces facing each other on the outer peripheral edge of the left and right divided transmission cases. And the power transmission device is accommodated inside by fastening with bolts.

JP-A-2005-273863

In the transmission case disclosed in Patent Document 1, the left transmission case on the outside of the vehicle body supports the left end of the driven shaft via a bearing.
Therefore, a bearing recess is formed in the left transmission case to fit the outer ring of the bearing.

  In the left transmission case, the bearing recess is inserted into the outer ring of the bearing with the inner ring fitted to the left end of the driven shaft so as to cover the power transmission device disposed on the left inner surface of the right transmission case. The mating surface is aligned with the mating surface of the outer peripheral edge of the right transmission case, and is attached to the right case by screwing and tightening with bolts.

  In this way, the left transmission case is attached to the right transmission case, so when removing the left transmission case for maintenance, etc., the bearing recess of the left transmission case is fitted to the left end of the driven shaft even if the bolt is loosened. The left transmission case may not be easily removed because it is fitted to the outer ring.

  That is, it is necessary to move the left transmission case to the left with respect to the right transmission case to extract the bearing recess fitted to the outer ring of the bearing, but the outer peripheral surface of the left transmission case is parallel to the extraction direction. The force in the direction cannot be effectively applied, and the removal work may take time.

  The present invention has been made in view of the above points, and the intended process is that one transmission case of the transmission case configured to be divided into left and right parts can be easily removed, and labor and time are not required for the removal work. The power unit transmission case has excellent workability.

  In order to achieve the above object, according to a first aspect of the present invention, a power transmission means is provided between a drive shaft that is rotated by the power of an internal combustion engine of a power unit mounted on a vehicle and a driven shaft that is linked to a rear wheel. The left and right transmission cases divided into the left and right transmission cases accommodate the power transmission device, and the transmission case arranged on the outside of the vehicle body of the left and right transmission cases fits the end of the driven shaft into the bearing recess via the bearing. In the transmission case structure that is pivotally supported in a rotatable manner, the left and right outer peripheral edge portions that constitute the facing surfaces of the left and right transmission cases that are opposed to each other at positions substantially symmetrical with respect to the driven shaft. A power unit transmission case structure is provided in which the pieces are respectively formed on the left and right transmission cases.

  According to a second aspect of the present invention, in the transmission case structure of the power unit according to the first aspect, a gap is formed between the projecting pieces facing each other.

  According to a third aspect of the present invention, in the power unit transmission case structure according to the first or second aspect, the power transmission device has an endless belt as a power transmission means between the drive shaft and the driven shaft. A belt-type continuously variable transmission is provided, wherein the left and right transmission case extends rearward from a front drive shaft and pivotally supports a rear driven shaft.

  According to the transmission case structure of the power unit according to claim 1, the left and right outer peripheral edge portions constituting the facing surfaces of the left and right transmission cases that are opposed to each other at positions substantially symmetrical with respect to the driven shaft. Since the pieces are formed on the left and right transmission cases, if a tool is inserted between the projecting pieces facing each other and the space between the projecting pieces is enlarged, the inner ring is fitted on the driven shaft. The force acts effectively in the direction of pulling out the worn bearing recess, and the bearing recess can be easily removed, and one transmission case can be easily removed without damaging the external appearance of the transmission case. Excellent workability.

  According to the transmission case structure of the power unit according to claim 2, since the gap is formed between the projecting pieces facing each other, a tool can be easily inserted between the projecting pieces facing each other, and the workability of the removal is increased. improves.

  According to the transmission case structure of the power unit according to claim 3, the power transmission device is a belt-type continuously variable transmission in which an endless belt as power transmission means is bridged between the drive shaft and the driven shaft. The left and right transmission cases extend rearward from the front drive shaft and pivotally support the rear driven shaft. Therefore, the left and right transmission cases of the belt-type continuously variable transmission are long in the front and rear directions, and the transmission case itself is rigid. The force when removing one of the transmission cases is less likely to be transmitted to the bearing recess fitted to the outer ring of the bearing, but they are located almost symmetrically with the driven shaft and facing each other at a position close to the bearing. A tool is inserted between the projecting pieces, and a force acts to expand the space between the projecting pieces, so that the force acts effectively in the direction of extracting the bearing recess fitted to the outer ring of the bearing, and the transmission case is Don't transform , Can be easily removed one of the transmission case, it is possible to maintain high workability removal.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
A power unit P according to the present embodiment is mounted on a motorcycle. FIG. 1 shows a side view of the power unit P with a part thereof omitted, and FIG. 2 shows a cross-sectional view thereof.

  The power unit P is provided at the rear part of the belt-type continuously variable transmission T and the belt-type continuously variable transmission T, which are an internal combustion engine E on the front side of the vehicle body and a power transmission device that is biased to the left and extends rearward from the internal combustion engine E. And a reduction gear mechanism R.

  The internal combustion engine E is a one-cylinder four-stroke internal combustion engine. The unit case 11 of the power unit P is divided into left and right parts, and includes a left unit case 11L and a right unit case 11R, and is slidable on the cylinder bore 12a of the cylinder block 12. The reciprocating motion of the fitted piston 16 is transmitted via the connecting rod 17 to the crankshaft 15 that is rotatably supported by the unit case 11 in the left-right direction, and the crankshaft 15 is rotated.

The cylinder block 12 tilts forward to near horizontal and protrudes forward from the unit case 11. The cylinder head 13 is overlaid on the cylinder block 12, and the cylinder head cover 14 covers the valve mechanism 20 provided on the cylinder head 13. Yes.
An intake rocker arm 22i and a rocker arm 22e are slidably in contact with the camshaft 21 of the valve mechanism 20, and an intake valve and an exhaust valve (not shown) are driven to open and close by the intake rocker arm 22i and the rocker arm 22e.

The camshaft has a reduction ratio of 1/2 that of the crankshaft 15 by a timing chain 24 spanned between a driven sprocket 23b fitted to the right end of the camshaft 21 and a drive sprocket 23a fitted to the crankshaft 15. 21 is rotated.
In addition, an ignition plug 26 is attached to the cylinder head 13 such that an electrode is exposed to a combustion chamber 25 defined by a ceiling surface facing the top surface of the piston 16.

  The crankshaft 15 is rotatably supported by the left unit case 11L and the right unit case 11R via main bearings 10 and 10, and the right end of the crankshaft 15 protruding rightward from the main bearing 10 on the right side is AC. The outer rotor 27r of the generator 27 is fitted, the right side thereof is covered by a generator cover 28 coupled to the right unit case 11R, and the inner stator 27s of the AC generator 27 is attached to the generator cover 28.

The left unit case 11L extends rearward and is long in the front-rear direction and is open toward the left.
A portion of the left unit case 11L opened to the left is covered with a transmission case cover 70 from the left, and a power transmission chamber C for accommodating the belt type continuously variable transmission T is formed therein.

  That is, the left unit case 11L and the transmission case cover 70 constitute a transmission case, the right transmission case obtained by dividing the transmission case into left and right parts is the left unit case 11L, and the left transmission case is the transmission case cover 70. is there.

A drive pulley 30 of a belt-type continuously variable transmission T is attached to a left end portion protruding leftward from a main bearing 10 provided in the left unit case 11L of the crankshaft 15.
The drive pulley 30 is fixed in the axial direction and the rotational direction with respect to the crankshaft 15 serving as a drive shaft, and has a drive side fixed pulley half 30a having a conical surface with which the V belt 32 contacts, and the drive side fixed pulley half. A drive-side movable pulley piece 30b having a conical surface, which is located on the right side of the body 30a, is axially movable with respect to the crankshaft 15 and is nonmovable in the rotational direction and is in contact with the V-belt 32; 15 includes a lamp plate 30c fixed in the axial direction and the rotational direction, and a plurality of weight rollers 30d disposed between the driving side movable pulley piece 30b and the lamp plate 30c.

On the other hand, at the rear of the power transmission chamber C, a driven shaft 50 with respect to the drive shaft (crankshaft 15) is freely rotatable to the left unit case 11L, the transmission case cover 70, and the gear case cover 51 via respective bearings 34, 35, and 36. Is pivotally supported.
A rotary sleeve 37 is coaxially supported on the driven shaft 50 via bearings 38 and 39 so as to be relatively rotatable. A driven pulley 40 that is paired with the drive pulley 30 is provided on the rotary sleeve 37.

  The driven pulley 40 is integrally attached to the rotary sleeve 37, and is driven side fixed pulley half 40a that is prohibited from moving in the axial direction. The driven pulley 40 is movable in the axial direction on the outer periphery of the rotary sleeve 37 and is slightly movable in the rotational direction. A driven-side movable pulley half 40b and a cylindrical compression coil spring 40c that urges the driven-side movable pulley half 40b toward the driven-side fixed pulley half 40a.

  The V-belt 32 wound around the conical surfaces of the driving-side fixed pulley half 30a and the driving-side movable pulley piece 30b of the driving pulley 30 at the front is the rear side of the driven-side fixed pulley half 40a of the driven pulley 40. And the driven conical pulley half 40b.

  Since the belt-type continuously variable transmission T is configured as described above, when the rotational speed of the internal combustion engine 11 is low, in the driving pulley 30, the driving-side movable pulley half 30b is separated from the driving-side fixed pulley half 30a. Thus, the winding radius of the V-belt 32 is reduced, and in the driven pulley 40, the driven-side movable pulley half 40b urged by the compression coil spring 40c approaches the driven-side fixed pulley half 40a, and the V-belt Since the winding radius of 32 is increased, the power of the crankshaft 15 is transmitted to the output shaft with a large gear ratio.

  When the rotational speed increases, in the driving pulley 30, the plurality of weight rollers 30d move radially outward by centrifugal force so that the driving-side movable pulley half 30b approaches the driving-side fixed pulley half 30a. As a result, the winding radius of the V-belt 32 is increased, and in the driven pulley 40, the driven-side movable pulley half 40 moves away from the driven-side fixed pulley half 40 against the spring force of the spring 40, and the V-belt Since the winding radius of 32 is small, the gear ratio is small.

  A clutch outer 48 of the centrifugal clutch L is fitted to a driven shaft 50 extending to the left side from the left end of the rotating sleeve 37, and the drive plate 45 is attached to the left end of the rotating sleeve 37 inside the hook-shaped clutch outer 48. It is fitted and provided.

  When the rotating sleeve 37 rotates at a rotational speed greater than a predetermined rotational speed, a plurality of clutch shoes 46 supported by the drive plate 45 in a swingable manner are diametrically caused by centrifugal force against the spring force of the clutch spring 47. The friction member 46a provided on the outer peripheral surface of each clutch shoe 46 abuts on the inner peripheral surface of the clutch outer 48, and the centrifugal clutch L is connected, and the rotation of the driven pulley 40 is driven by the driven shaft. Transmitted to 50.

A gear case cover 51 is put on the right side of the rear portion of the left unit case 11L to form a reduction gear chamber 52, and the reduction gear mechanism R is accommodated in the reduction gear chamber 52.
In the reduction gear chamber 52, a reduction gear shaft 53 is rotatably supported via bearings 54 and 54 in parallel with the driven shaft 50, and a rear axle 55 is rotatably supported via bearings 56 and 56. The rear axle 55 passes through the gear case cover 51 and protrudes the right half to the outside, and the rear wheel is supported by the right half.

A small-diameter gear 50a is formed in a portion of the driven shaft 50 protruding into the reduction gear chamber 52, and a large-diameter gear 53a formed integrally with the reduction gear shaft 53 meshes with the small-diameter gear 50a and is integrated with the reduction gear shaft 53. The formed small diameter gear 53b meshes with a large diameter gear 55a fitted to the rear axle 55.
Therefore, the rotation of the driven shaft 50 is decelerated via the reduction gear mechanism R and transmitted to the rear axle 55, and the rear wheels are rotated.

As described above, the power of the belt-type continuously variable transmission T crankshaft 15 of the internal combustion engine E is input to the drive pulley 30 of the belt-type continuously variable transmission T, and the belt-type continuously variable transmission T The gear is automatically shifted at a gear ratio corresponding to the rotational speed and transmitted to the driven pulley 40, and further transmitted to the driven shaft 50 via the centrifugal clutch L.
The rotation of the driven shaft 50 is transmitted to the rear axle 55 after being decelerated by the reduction gear mechanism R.

  The transmission case cover 70 and the left unit case 11L constituting the power transmission chamber C that accommodates the belt-type continuously variable transmission T are long in the front-rear direction and correspond to a left transmission case and a right transmission case that are divided left and right. The mating surfaces 71a and 61a are in the same vertical plane, and are formed in an annular shape along the outer peripheries 71 and 61 that are long in the front and rear directions (see FIGS. 1 and 4).

  As shown in FIGS. 3 and 4, the transmission case cover 70 has an annular outer peripheral edge 71 constituting the mating surface 71 a, and a notch opening 72, which is an air outlet, is formed in the lower rear part. A groove 71b into which the seal member 80 is inserted is formed on the mating surface 71a of the outer peripheral edge 71 excluding the notch opening 72.

A plurality of mounting boss portions 73 are formed on the outer peripheral edge portion 71 of the transmission case cover 70 so that bolt fastening holes are formed along the mating surface 71a.
Further, a mounting boss 74 is formed in the substantially central portion of the transmission case cover 70 so as to protrude into the power transmission chamber C to the mating surface 71a.

  The portion of the transmission case cover 70 facing the front crankshaft 15 is formed with a circular opening 75 for sucking air, and the portion facing the rear driven shaft 50 is formed with a bearing recess 76 into which the outer ring of the bearing 35 is fitted. Has been.

The outer peripheral edge 71 of the transmission case cover 70 is a rectangle having the same surface as the mating surface 71a along the mating surface 71a at a position substantially symmetrical with respect to the bearing recess 76 (or the driven shaft 50). Plate-like projecting pieces 77 and 78 are formed.
The upper protruding piece 77 is formed integrally with the mounting boss 73.

  Referring to FIG. 1, the left unit case 11 </ b> L covered with the transmission case cover 70 has a notch opening corresponding to the notch opening 72, with the mating surface 61 a of the outer peripheral edge 61 facing the mating surface 71 a. A portion 62 is formed.

On the outer peripheral edge 61 of the left unit case 11L, there are formed mounting bosses 63 in which female screws are engraved corresponding to the plurality of mounting bosses 73 of the transmission case cover 70, respectively.
The mounting boss 63 has the same surface as the mating surface 61a.
A mounting boss portion 64 is formed in a substantially central portion of the left unit case 11L so as to protrude into the power transmission chamber C to the mating surface 61a corresponding to the mounting boss portion 74 of the transmission case cover 70.

And the rectangular plate-shaped protrusions 67 and 68 are formed in the outer peripheral edge 61 of the left unit case 11L facing the protrusions 77 and 78 of the transmission case cover 70.
The protruding pieces 67 and 68 are formed at positions that are substantially vertically symmetrical with respect to the driven shaft 50 and are slightly pulled to the right from the mating surface 61a.

  When the transmission case cover 70 is attached to the left unit case 11L as described above, the bearing recess 76 of the transmission case cover 70 is fitted to the outer ring of the bearing 35 in which the inner ring is fitted to the left end of the driven shaft 50. Then, the mating surface 71a in which the sealing member 80 is inserted into the groove 71b of the outer peripheral edge 71 of the transmission case cover 70 is brought into contact with the mating surface 61a of the outer peripheral edge 61 of the left unit case 11L, and the bolt 81 is transmitted. It is inserted into the holes of the mounting boss parts 63 and 64 of the case cover 70, screwed into the female threads of the mounting boss parts 73 and 74 of the left unit case 11L, and tightened.

  When the transmission case cover 70 is attached to the left unit case 11L in this way, as shown in FIGS. 5 and 6, the protruding pieces 67 of the left unit case 11L with respect to the protruding pieces 77 and 78 on the transmission case cover 70 side. 68 are opposed to each other with a gap.

A front L cover 82 is attached to the front left side of the transmission case cover 70 attached to the left unit case 11L to cover the circular opening 75 of the transmission case cover 70.
A fan 83 is formed on the left side surface of the driving-side fixed pulley half 30a fitted to the crankshaft 15. When the driving-side fixed pulley half 30a rotates together with the crankshaft 15, the fan 83 rotates to open a circle. Air is sucked into the power transmission chamber C from 75, the belt type continuously variable transmission T is cooled, and discharged from the rear notch openings 62 and 72.

  When removing the transmission case cover 70 from the left unit case 11L for maintenance or the like, first remove the bolt 81 and pull the transmission case cover 70 to the left with respect to the left unit case 11L. Since 70 bearing recesses 76 are fitted to the outer ring of the bearing 35 provided at the left end of the driven shaft 50, it is not easy to remove.

  Therefore, in the transmission case structure of the present embodiment, the tip is flat in the gap between the protruding piece 77 on the transmission case cover 70 and the protruding piece 67 of the left unit case 11L facing each other above the driven shaft 50. By inserting the tip of a tool such as a pointed flat-blade screwdriver and tilting it with the base end to expand the gap, the upper side of the transmission case cover 70 can be easily moved to the left using the lever principle. Similarly, a tool is inserted into the gap between the projecting piece 78 on the side of the transmission case cover 70 and the projecting piece 68 of the left unit case 11L facing each other below the driven shaft 50 so as to enlarge the gap. By operating the, the lower side of the transmission case cover 70 can be easily moved to the left.

  That is, since the transmission case cover 70 can be moved to the left with respect to the left unit case 11L at the vertical position of the transmission case cover 70 close to the bearing recess 76 fitted to the outer ring of the bearing 35, it is fitted to the outer ring of the bearing 35. A force is effectively applied in the direction in which the bearing recess 76 is extracted, so that the bearing recess 76 can be easily extracted. If the bearing recess 76 is removed, the transmission case cover 70 is removed.

  In this way, the transmission case cover 70 can be easily removed from the left unit case 11L without deforming or damaging the transmission case cover 70, and the removal workability is excellent.

  The projecting pieces 67 and 68 of the left unit case 11L and the projecting pieces 77 and 78 of the transmission case cover 70 are used when the left unit case 11L and the transmission case cover 70 are processed when the left unit case 11L and the transmission case cover 70 are processed. It can also be used as a presser piece for fixing.

It is the side view which abbreviate | omitted one part of the power unit which concerns on one embodiment of this invention. It is sectional drawing of the power unit. It is a side view of a transmission case cover. It is a reverse view of the transmission case cover. It is the perspective view which looked at the rear part of the power unit from diagonally upward. It is the perspective view which looked at the rear part of the power unit from diagonally downward.

Explanation of symbols

P: Power unit, E: Internal combustion engine, T: Belt type continuously variable transmission, C: Power transmission chamber, L: Centrifugal clutch, R ... Reduction gear mechanism,
11 ... Unit case, 11L ... Left unit case, 11R ... Right unit case,
15 ... Crankshaft, 30 ... Driving pulley, 32 ... V belt, 35 ... Bearing, 40 ... Driving pulley, 50 ... Driving shaft, 55 ... Rear axle
61 ... Outer peripheral edge part, 61a ... Mating surface, 63, 64 ... Mounting boss part, 67, 68 ... Projection piece,
70 ... Transmission case cover, 71 ... Outer peripheral edge, 71a ... Mating surface, 71b ... Groove, 73, 74 ... Mounting boss, 76 ... Bearing recess, 77, 78 ... Projection piece, 80 ... Sealing member.

Claims (3)

A left and right transmission case divided into left and right houses a power transmission device in which a power transmission means is interposed between a drive shaft that is rotated by the power of an internal combustion engine of a power unit mounted on a vehicle and a driven shaft that is linked to a rear wheel. And
In the transmission case structure in which the transmission case arranged on the outside of the vehicle body among the left and right transmission cases is rotatably supported by fitting the end portion of the driven shaft into the bearing recess through the bearing,
The left and right outer peripheral edges constituting the facing surfaces of the left and right transmission cases that are opposite to each other, and projecting pieces that face each other are formed on the left and right transmission cases at positions that are substantially symmetrical with respect to the driven shaft. The power unit transmission case structure.   The power case transmission case structure according to claim 1, wherein a gap is formed between the projecting pieces facing each other. The power transmission device is a belt-type continuously variable transmission in which an endless belt as power transmission means is bridged between the drive shaft and the driven shaft.
3. The power unit transmission case structure according to claim 1, wherein the left and right transmission case extends rearward from a front drive shaft and pivotally supports a rear driven shaft. 4.

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