CN100497921C

CN100497921C - Vehicular power equipment

Info

Publication number: CN100497921C
Application number: CNB031580149A
Authority: CN
Inventors: 锅谷真; 池田直机
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2002-07-19
Filing date: 2003-07-16
Publication date: 2009-06-10
Anticipated expiration: 2023-07-16
Also published as: JP2004052908A; ITTO20030548A1; ES2251275B1; CN1488850A; ES2251275A1

Abstract

To improve workability of a connection surface arranged on a crankcase in a power unit for loading vehicles which contains a transmission gear including a V-belt type continuously variable transmission having a driving pulley mounted on one end part of a crankshaft in a transmission case at least a part of which is constituted of a cover and a case part connected to each other, where the connection surface for connecting a cylinder block is arranged on the crankcase and the case part extending outward from the outside surface of the cylinder block is arranged in one component.Within a range where a part of the crankcase 21 provided with the connection surface 36 is projected in the axial direction of the crankshaft 25, the peripheral surface of the case part 56 extends from a part corresponding to a driving pulley 67 to the cover 57 side end of the case part 56, has a plane surface part 95 parallel to the connection surface 36, and forms no protruding part closer to the cylinder block 22 than a plane surface L including the connection surface 36.(C)2004,JPO.

Description

The vehicle mounted power equipment

Technical field

The present invention relates to the vehicle mounted power equipment, in this power equipment, in the crank box of supporting crankshaft free to rotate, be provided with the smooth fitting surface that can cooperate with cylinder block and form, and be provided with the cylinder block outer side surface more outwardly directed box main body more outside than aforementioned cylinder block along aforementioned crankshaft axis integral body; Constitute in the transmission case folding and unfolding and transmission device being coupled to backplate on the aforementioned box main body and aforementioned box main body place at least a portion by packing ring; This transmission device is inserted into has V belt buncher between aforementioned crankshaft and the driving wheel, this V belt buncher has the drive pulley that is installed on aforementioned crankshaft one end.

Background technique

This power equipment is in the past for example opened in the flat 8-277937 communique open the spy.

But, because in above-mentioned vehicle mounted power equipment in the past, make the part that fitting surface is set in the crank box along in the crank box axis drop shadow spread at whole box main body that be provided with, the more outwardly directed axis along crankshaft than the outer side surface of cylinder block on the crank box, has the protuberance that more stretches out than aforementioned fitting surface to cylinder block side, so when carrying out the fitting surface cutting, must avoid the aforementioned protuberance on the box main body, have good processability hardly.

Summary of the invention

The present invention proposes in view of the above problems, and its purpose is to provide a kind of vehicle mounted power equipment, and this power equipment can improve the processability that is arranged on the fitting surface on the crank box main body when cooperating cylinder block.

In order to achieve the above object, first aspect present invention provides a kind of vehicle mounted power equipment, on the crank box that supports crankshaft (25) (21) free to rotately, be provided with the flat condition fitting surface (36) that can cooperate cylinder block (22), and, be wholely set the outwardly directed box main body of outer side surface (56) from aforementioned cylinder block (22) along the axis of aforementioned crankshaft (25); By the backplate (57) and the aforementioned box main body (56) that cooperate with aforementioned box main body (56) by packing ring (59), constitute at least a portion of transmission case (55), transmission device (M) in folding and unfolding in this transmission case (55); This transmission device (M) is inserted between aforementioned crankshaft (25) and the driving wheel (WR), and has V belt buncher (65); This V belt buncher (65) has the drive pulley (67) that is installed on aforementioned crankshaft (25) one ends;

This vehicle mounted power equipment is characterised in that: make the part that is provided with aforementioned fitting surface (36) in the aforementioned crank box (21) along crankshaft (25) axial direction projection, in this drop shadow spread, the outer circumferential face of aforementioned box main body (56) forms following shape: promptly have planar surface portion (95), and cylinder block (22) one sides on a plane (L) that comprises aforementioned fitting surface (36) do not have projection, aforementioned planar surface portion (95) is stretched over aforementioned backplate (57) the side edge of aforementioned box main body (56) at least from the part corresponding with aforementioned drive pulley (67), and parallel with aforementioned fitting surface (36).

Structure according to first aspect present invention, because the whole outer circumferential face that is arranged on the box main body on the crank box, the part that aforementioned fitting surface is set in making aforementioned at least crank box is along in the crankshaft axial direction drop shadow spread, have the planar surface portion parallel with aforementioned fitting surface, and the part that the shape that forms is not more given prominence to cylinder block side from a plane that comprises aforementioned fitting surface, so, when carrying out the cutting of fitting surface, can not be subjected to the overslaugh of box main body outer circumferential face.In addition, because planar surface portion is to form with the form that is stretched over the backplate side edge of box main body from the part of corresponding drive pulley at least, thereby the interval that can not only increase as much as possible between drive pulley and box main body inner face guarantees that drive pulley rotates fully, can also improve the processability of aforementioned fitting surface.

Second aspect present invention constitutes on the first aspect present invention basis, on the outer circumferential face of aforementioned backplate (57), be formed with the planar surface portion (100) of the ora terminalis that is stretched over aforementioned box main body (56) one sides corresponding to aforementioned planar surface portion (95), and in part corresponding to packing ring (59), disposing the maximum diameter part (91) in the aforementioned drive pulley (67), in part, make the interior week of engaging Sealing (59a) recessed corresponding to aforementioned two planar surface portion (95,100); This packing ring (59) has the engaging Sealing (59a) of the approximate U word shape in cross section on box main body (56) side end that is engaged in the backplate (57), and is inserted between aforementioned box main body (56) and the backplate (57).

According to the structure of second aspect present invention, because the engaging Sealing of packing ring forms cross section nearly U word shape and is engaged to the box main body side end of backplate, can not only prevent the position deflection that packing ring produces from breaking away between box main body and backplate, and can also assembled washer.In addition, the shape because the part of the planar surface portion that the engaging Sealing forms respectively at the outer circumferential face of box main body and backplate in correspondence is in line certainly, and the part in the described planar surface portion of correspondence makes the interior week of engaging Sealing recessed, even so maximum diameter in the drive pulley partly is configured in the position of corresponding packing ring, also can avoid the interference of drive pulley and packing ring, can also make the part that covers drive pulley in box main body and the backplate form minimum diameter as much as possible.

Third aspect present invention is to constitute on the basis of above-mentioned first aspect or second aspect, in aforementioned planar surface portion (95), the guard shield (45) of the cylinder head (23) that is covered with cylinder block (22) and cooperates with this cylinder block (22) is installed, this planar surface portion (95) is processed into flat condition simultaneously and is in same plane with aforementioned fitting surface (36) with aforementioned fitting surface (36), and is formed on the aforementioned box main body (56).According to this structure,,, thereby improve cooling performance simultaneously because of having improved the dimensional accuracy that fitting surface and planar surface portion relative positional accuracy can improve the cold passageway that forms in the guard shield because of processing the auxiliary section simultaneously and planar surface portion improves processability.

Description of drawings

Fig. 1 is the pedal-type two-wheel motorcycle side view;

Fig. 2 is the side view of power equipment;

Fig. 3 is the sectional drawing along 3-3 line among Fig. 2;

Fig. 4 is the sectional drawing along 4-4 line among Fig. 2;

Fig. 5 is the enlarged view of major component shown in Fig. 3;

Fig. 6 is the sectional drawing along 6-6 line among Fig. 3.

Label declaration

The 21st, crank box, the 22nd, cylinder block, the 23rd, cylinder head, the 25th, crankshaft, the 36th, fitting surface, the 45th, guard shield, the 55th, transmission case, the 56th, box main body, the 57th, backplate, the 59th, packing ring, 59a is the engaging Sealing, the 67th, and drive pulley, the 65th, buncher, the 91st, maximum diameter partly is a ring gear, the 95, the 100th, and planar surface portion, L is a plane, M is a transmission device, and P is a power equipment, and WR is the trailing wheel as driving wheel.

Embodiment

Below, the one embodiment of the present of invention shown in illustrate embodiments of the present invention with reference to the accompanying drawings.

Fig. 1 to Fig. 6 is the figure that shows one embodiment of the invention, Fig. 1 is the pedal-type two-wheel motorcycle side view, Fig. 2 is the side view of power equipment P, Fig. 3 is the sectional drawing along 3-3 line among Fig. 2, Fig. 4 is the sectional drawing along 4-4 line among Fig. 2, Fig. 5 is the enlarged view of major component shown in Fig. 3, and Fig. 6 is the sectional drawing along 6-6 line among Fig. 3.

In addition, in the following description, so-called before and after and about be benchmark with the two-wheeled motor vehicle direction of travel.

At first, in Fig. 1, pedal-type two-wheel motorcycle vehicle frame 10 is made up of side arm 11 and after-frame 12; Side arm 11 is supporting from the beginning to manage 13 foot treadles 15 that are stretched over the front lower place, but head pipe 13 steerings supporting

front fork

14,14 of front forks are supporting front-wheel WF; After-frame 12 is supporting to be stretched over from side arm 11 rear portions storage box 16, fuel tank 17 and occupant's seat 18 of back upper place.On vehicle frame 10, it is that trailing wheel WR becomes can swing up and down shape the power equipment P suspension that drives this trailing wheel WR by suspension link 19 simultaneously that axle is supporting driving wheel; Between after-frame 12 and power equipment P, be provided with the rear portion buffer 20 that buffering power equipment P swings up and down.

In Fig. 2 to Fig. 4, the motor E of power equipment P has crank box 21, is coupled to the cylinder block 22 of crank box 21 front ends, the cylinder head 23 that cooperates with cylinder block 22 front ends with forward lean, forms engine main body 24.

The crankshaft 25 that has in the left and right directions extend axis is rotatably supported on the crank box 21; Engage with the cylinder barrel 26 that cylinder block 22 has slidably at piston 27, and be connected with crankshaft 25 with crank pin 29 by connecting rod 28; Igniter plug 30 is installed on cylinder head 23, and disposes valve mechanism 31; The top cover 32 that covers valve mechanism 31 cooperates with the front end of cylinder head 23.

Crank box 21 is the structures that are interconnected to constitute with a plurality of bolts 33 with left side case halfbody 21L that forms about the vertical surface division with cylinder barrel 26 axis and right side case halfbody 21R; Crankshaft 25 rotatable break-through left side and right side case halfbody case halfbody 21L, 21R; Between two case halfbody 21L, 21R and crankshaft 25, ball bearing 34,35 is installed respectively.

On this crank box 21, be provided with the smooth fitting surface 36 that can cooperate cylinder block 22, on the right side case halfbody 21R in crank box 21, the whole outstanding support tube 37 that is provided with coaxial around crankshaft 25.Dispose generator 40 in ball bearing 35 outsides, it has stator 38 and external rotor 39, and stator 38 is fixed on the aforementioned support tube 37, and external rotor 39 is fixed on the crankshaft 25 in the mode around this stator 38; In these generator 40 outsides, fan 41 is fixed on the crankshaft 25.The peripheral part integral body of the base portion 41a of this fan 41 on the external rotor 39 that is connected to generator 40 with a plurality of bolts 42 is provided with a plurality of

blade

41b, 41b....

The cylinder block 22 of engine main body 24 and cylinder head 23 are covered by guard shield 45, the pressure tempering air that is circulating in the circulation road 46 that forms between engine main body 24 and guard shield 45 and discharging from aforementioned fan 41.In order to improve the cooling effect of the cooling air of circulation in the aforementioned circulation road 46 effectively, also outstanding respectively a plurality of radiating fin 22a..., the 23a... of being provided with in the outside of cylinder block 22 and cylinder head 23.

Aforementioned guard shield 45 is to be made of up and down a pair of

backplate

47,48 and fan backplate 49, and upper guard board 47, backplate 48 cooperatively interacts can assist and moves covering cylinder block 22 and cylinder head 23 down; Fan backplate 49 matches with aforementioned two

backplates

47,48 of right side case halfbody 21R in being covered with crank box 21; Upper guard board 47, following backplate 48 and fan backplate 49 are formed by synthetic resin respectively.

On the case halfbody 21R of right side, be wholely set the pad plate 50 that protrudes tubular that can cover aforementioned generator 40, fan backplate 49 covers fans 41 and is connected with pad plate 50, and aforementioned pad plate 50 is provided with the cooling air of fan 41 is imported outlet 51 in the aforementioned circulation road 46.On fan backplate 49, be provided with at the foreign side of aforementioned fan 41 and corresponding fan 41 and attract tube 53, this attractions tins 53 has the attraction mouth 52 that is used for drawing to aforementioned fan 41 side draughts outside air; Attract mouth 52 to be provided with venetian blind 54.

Cooperation, connects the transmission case 55 that is placed with transmission device M on the left side case halfbody 21L in crank box 21 with reference to Fig. 5 in the left side mode that reaches trailing wheel WR, this transmission device M constitutes and the aforementioned motor E moving power equipment P of association.

This transmission case 55 is made of box main body 56, left backplate 57, right backplate 58; Box main body 56 is protruding and rearward stretch on the whole left side case halfbody 21L that is arranged on the crank box 21 from the outside of aforementioned cylinder block 22 along the axis of crankshaft 25; Left side backplate 57 is coupled on the box main body 56 from the left side by packing ring 59; Right backplate 58 is engaged in the rear portion, right side of aforesaid box main body 56; Between box main body 56 and left backplate 57, be formed with first Transmission Room 60, between box main body 56 and right backplate 58, be formed with second Transmission Room 61; Box main body 56 rear portions and right backplate 58 places of axletree 62 free rotation ground supportings of trailing wheel WR in transmission case 55.

Aforementioned transmission device M by folding and unfolding in first Transmission Room 60 V belt buncher 65 and be arranged on buncher 65 and aforementioned axletree 62 between train of reduction gears 66 constitute.

Buncher 65 comprises that drive pulley 67, negative pulley wheel 68 and ring-type V are with 69; Drive pulley 67 is installed in an end of crankshaft 25; Negative pulley wheel 68 is contained on the driven axle 70 by centrifugal clutch 71, and driven axle 70 has axis parallel with crankshaft 25 and back and right backplate 58 places that are bearing in box main body 56 free to rotate; Ring-type V is with 69 volumes to hang on drive pulley 67 and the negative pulley wheel 68.

Drive pulley 67 by belt pulley fixedly halfbody 72 and belt pulley movable halves 73 constitute, belt pulley fixedly halfbody 72 is fixed on the distolateral of crankshaft 25, belt pulley movable halves 73 can be installed in belt pulley axially slidably, and fixedly halfbody 72 is axially inboard.In the V word shape circular groove 74 of 72,73 formation of two half-pulley, insert V and be with 69.Be fixed on the crankshaft 25 at the back side of belt pulley movable halves 73 swash plate 75; Between belt pulley movable halves 73 and swash plate 75, a plurality of counterweight roller 76... with the floating type folding and unfolding.Along with the revolution of crankshaft 25 increases, the counterweight roller 76... that bears centrifugal force moves to the radially foreign side of crankshaft 25, makes belt pulley movable halves 73 near the fixing halfbody 72 of belt pulley, thereby V becomes greatly with the contact radius of 69 pairs two half-

pulley

72,73.

Negative pulley wheel 68 comprises supports tube 77, belt pulley fixedly halfbody 78 and belt pulley movable halves 79; Support tube 77 to be attached to driven axle 70 and to be supported to shape free to rotate by driven axle 70 by centrifugal clutch 71; Belt pulley fixedly halfbody 78 is fixed on this support tube 77; Belt pulley movable halves 79 by support tube 77 support can near and away from this belt pulley fixedly halfbody 78 time to fixedly the direction elasticity of halfbody 78 is pressured near belt pulley.In the V word shape annular groove 80 of 78,79 formation of two half-pulley, insert V and be with 69.Along with the radius change of V band contact drive pulley 67 is big, belt pulley movable halves 79 is moving axially so that this V diminishes with the radiuses of 69 contact negative pulley wheels 68, thereby can carry out the stepless change of rotation of the crankshaft 25 of 70 of corresponding crankshaft 25 and driven axles.

Train of reduction gears 66 is arranged between driven axle 70 and the axletree 62, and folding and unfolding is in second Transmission Room 61; The rotatory force of the driven axle 70 in the buncher 65 relies on train of reduction gears 66 decelerations and passes to the axletree 62 of trailing wheel WR.

On the left backplate 57 in transmission case 55, bounce-back axle 83 is supported freely to rotate shape, and foot treadle 84 (referring to Fig. 1) is arranged on the outer end of this bounce-back spools 83.Inner face place at the aforementioned left backplate 57 of 25 of bounce-back axle 83 and crankshafts is provided with bounce-back formula starting mechanism 85, and the power of stepping on the bounce-back axle 83 of pedaling the operation generation of its corresponding foot treadle 84 sends crankshaft 25 to.

Cooperation is referring to Fig. 6, and the belt pulley in drive pulley 67 fixedly halfbody 72 periphery integral body is formed with ring gear 91 with small gear 90 engagements of starter 86.Starter 86 is made of starting motor 87 and starting conveyer 88, starting motor 87 is so that the output shaft 89 parallel with crankshaft 25 outstanding state in first Transmission Room 60 is connected on the box main body 56 of left side case halfbody 21L, and starting conveyer 88 sends the rotation of aforementioned output shaft 89 to aforementioned ring gear 91.

Starting conveyer 88 is to be made of structure known in the prior art.Have small gear supporting axis 93, small gear 90 and jump out mechanism 94, small gear supporting axis 93 is attached on the output shaft 89 of starting motor 87 by train of reduction gears 92, small gear 90 to be slidably to be supported on the small gear supporting axis 93 with ring gear 91 engageable disengaging shapes, jump out mechanism 94 can be when small gear supporting axis 93 rotates so that the form of small gear 90 and ring gear 91 engagements moving axially.

With in the crank box 21, be provided with the part of aforementioned fitting surface 36 along crankshaft 25 axial direction projections, in this drop shadow spread, the peripheral shape of box main body 56 becomes following shape: promptly have planar surface portion 95, and cylinder block 22 1 sides at a plane L who includes aforementioned fitting surface 36 do not form projection; This planar surface portion is at least from the part corresponding to the drive pulley 67 of buncher 65, extend to the left backplate 57 side edge of box main body 56, and it is parallel with fitting surface 36, in this embodiment, and aforementioned fitting surface 36 be on the outer circumferential face of box main body 56 between conplane planar surface portion 95 and the aforementioned fitting surface 36, from planar surface portion 95 and fitting surface 36, form recessed recess 96 to a side opposite with cylinder block 22.

Therefore, aforementioned planar surface portion 95 is processed into flat condition simultaneously with fitting surface 36, and the guard shield 45 that covers cylinder block 22, cylinder head 23 is installed on the planar surface portion 95.That is to say, extending to the inboard on the whole protuberance 97 that is arranged on the box main body 56 from part corresponding to aforementioned planar surface portion 95, be connected with the bolt 99 that will run through with the tubular elastic member 98 that aforementioned guard shield 45 cooperates, and aforementioned elastic member 98 is clamped between the head and planar surface portion 95 of this bolt 99, guard shield 45 is installed on the planar surface portion 95.

On the other hand, on the outer circumferential face of left backplate 97, be formed with corresponding to the aforementioned planar surface portion 95 of box main body 56 and extend to the planar surface portion 100 of the ora terminalis of box main body 56 sides, in part corresponding to packing ring 59, dispose the maximum diameter part in the aforementioned drive pulley 67, be ring gear 91, in the part corresponding with two planar surface portion 95,100, the interior all sides of the engaging Sealing 59a in packing ring 59 are formed with the recessed reentrant part 59b in part shown in Figure 6.This packing ring 59 have with box main body 56 sides of left backplate 57 engage, the engaging Sealing 59a of the approximate U word shape in cross section, and be installed between box main body 56 and the left backplate 57.

Drive pulley 67 middle belt pulleys fixedly the V of halfbody 72 with the face at 69 back sides on outstanding a plurality of blades 101, the 101... that is provided with radial configuration, belt pulley fixedly halfbody 72 also has the function of blowing fan.The belt pulley that correspondence has a blowing fan function is the air of rotation in first Transmission Room 60 of halfbody 72 fixedly, is discharged to the outside by connecting tube 102 that is arranged on left backplate 57 front portions and the pipeline 103 (referring to Fig. 1) that is connected on this connecting tube 102.

Below, this embodiment's effect is described.In the engine main body 24 on the motor E among the power equipment P of lift-launch on pedal-type two-wheel motorcycle, crank box 21 is made of left case halfbody 21L and right case halfbody 21R cooperation, and crank box 21 is provided with the smooth fitting surface 36 that is used to cooperate cylinder block 22.In addition, be wholely set the box main body 56 that stretches out from cylinder block 22 outside sides at left case halfbody 21L upper edge crankshaft 25 axis, by packing ring 59 constitute by left backplate 57 that cooperates with box main body 56 and box main body 56 part transmission case 55 in, the transmission device M of the buncher 65 that has the V belt in folding and unfolding, and this buncher 65 has the drive pulley 67 that is installed on crankshaft 25 1 ends.The part that is provided with fitting surface 36 in making crank box 21 is along in the scope of crankshaft 25 axial direction projections, the outer circumferential face of box main body 56 forms following shape: promptly have planar surface portion 95, and cylinder block 22 1 sides from the plane L that comprises fitting surface 36 do not have projection.This planar surface portion 95 is stretched over the left backplate 57 side edge of box main body 56 and parallel with fitting surface 36 from the part of the aforementioned drive pulley 67 of correspondence at least.

Therefore, when carrying out the cutting of fitting surface 36, can not be subjected to the obstruction of box main body 56 outer circumferential faces.In addition, because planar surface portion 95 is stretched over the left backplate 57 side edge formation of box main body 56 at least from the part of the aforementioned drive pulley 67 of correspondence, can not only do one's utmost to increase the interval between drive pulley 67 and box main body 56 inner faces and guarantee that drive pulley 67 rotates fully, can also improve the processability of aforementioned fitting surface 36.

On the outer circumferential face of left backplate 57, be formed with the planar surface portion 100 that is stretched over box main body 56 side edge places corresponding to aforementioned planar surface portion 95, in part corresponding to packing ring 59, maximum diameter partly is a ring gear 91 in the configuration driven belt pulley 67, in part, make the interior week of engaging Sealing 59a recessed corresponding to two planar surface portion 95,100.This packing ring 59 has engaging Sealing 59a on the end that is engaged to box main body 56 sides, the approximate U word shape in cross section, and is installed between box main body 56 and the left backplate 57.

By like this this packing ring 59 being inserted between box main body 56 and the left backplate 57, can prevent the position deflection that packing ring 59 produces from breaking away between box main body 56 and the left backplate 57, and can assembled washer 59.In addition, the part of the planar surface portion 95,100 that engaging Sealing 59a forms respectively at the outer circumferential face of corresponding box main body 56 and left backplate 57 shape that is in line certainly, owing in part, make the interior week of engaging Sealing 59a recessed corresponding to planar surface portion 95,100, partly is maximum diameter in the drive pulley 67 that ring gear 91 is configured in the position corresponding to packing ring 59, not only avoid the interference of drive pulley 67 and packing ring 59, can also make the part that covers drive pulley 67 in box main body 56 and the left backplate 57 form minimum diameter as much as possible.

In addition, because the planar surface portion 95 in the box main body 56 is in same plane with fitting surface 36, and is processed into flat condition simultaneously with fitting surface 36, can improve processability.In addition, because the guard shield 45 that covers cylinder block 22 and cylinder head 23 is installed on planar surface portion 95, fitting surface 36 and planar surface portion 95 can improve circulation road 46 dimensional accuracies of the cooling air that forms in the guard shield 45 because of processing its phase position precision height simultaneously, thereby can improve cooling property.

Embodiments of the invention more than have been described, but the present invention is not limited to the foregoing description, the present invention who puts down in writing in not breaking away from the Patent right requirement scope can carry out all changes that is provided with.

The invention effect

According to first aspect present invention, when the machining mating surface, can not be subjected to the harm of box main body outer peripheral face Hinder, can not only increase as much as possible the interval between drive pulley and box main body inner face and guarantee to drive belt Wheel rotates fully, can also improve the processability of aforementioned mating surface.

According to second aspect present invention, can not only prevent what packing ring from producing from breaking away between box main body and backplate Position skew, and can also assembled washer; Can not only avoid the phase mutual interference of drive pulley and packing ring, Can also make as far as possible the part that covers drive pulley in box main body and the backplate form minimum diameter.

According to third aspect present invention, when improving processability, because having improved mating surface and planar portions Relative positional accuracy and can improve in the guard shield dimensional accuracy of the cooling airflow passage that forms, thus improve cold But property.

Claims

1, a kind of vehicle mounted power equipment, on the crank box that supports crankshaft (25) (21) free to rotately, be provided with the flat condition fitting surface (36) that can cooperate cylinder block (22), and, be wholely set the outwardly directed box main body of outer side surface (56) from aforementioned cylinder block (22) along the axis of aforementioned crankshaft (25); By the backplate (57) and the aforementioned box main body (56) that cooperate with aforementioned box main body (56) by packing ring (59), constitute at least a portion of transmission case (55), transmission device (M) in folding and unfolding in this transmission case (55); This transmission device (M) is inserted between aforementioned crankshaft (25) and the driving wheel (WR), and has V belt buncher (65); This V belt buncher (65) has the drive pulley (67) that is installed on aforementioned crankshaft (25) one ends;

2, vehicle mounted power equipment as claimed in claim 1, it is characterized in that: on the outer circumferential face of aforementioned backplate (57), be formed with the planar surface portion (100) of the ora terminalis that is stretched over aforementioned box main body (56) one sides corresponding to aforementioned planar surface portion (95), and in part corresponding to packing ring (59), disposing the maximum diameter part (91) in the aforementioned drive pulley (67), in part, make the interior week of engaging Sealing (59a) recessed corresponding to aforementioned two planar surface portion (95,100); This packing ring (59) has the engaging Sealing (59a) of the approximate U word shape in cross section on box main body (56) side end that is engaged in the backplate (57), and is inserted between aforementioned box main body (56) and the backplate (57).

3, vehicle mounted power equipment as claimed in claim 1 or 2, it is characterized in that: in aforementioned planar surface portion (95), the guard shield (45) of the cylinder head (23) that is covered with cylinder block (22) and cooperates with this cylinder block (22) is installed, this planar surface portion (95) is processed into flat condition simultaneously and is in same plane with aforementioned fitting surface (36) with aforementioned fitting surface (36), and is formed on the aforementioned box main body (56).