JP2008149813A - Power unit for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power unit for a vehicle increased in rigidity without increasing a weight. <P>SOLUTION: This power unit 26 for a vehicle has an engine 39 mounted to a three-wheeled motorcycle 1 and outputting a rotary driving force from a crankshaft 46, and a transmitting device 57 and a differential device 63 transmitting the rotary driving forces of the crankshaft 46 to rear wheel shafts 53L, 53R, and is swingingly supported by a vehicle body. The unit has a transmission case 42 extending in the forward and backward direction of the vehicle and housing the transmitting device 57, and a gear case 68 mounted to the rear side of the transmission case 42 and housing the differential device 63. Muffler supporting parts 92, 93 are provided at the transmission case 42 and the gear case 68, respectively, and a muffler 29 is mounted to the muffler supporting parts 92, 93. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicular power unit with enhanced rigidity without increasing weight.

  In a tricycle, a power unit is formed by a transmission case that houses a transmission device and a gear case that houses a differential gear (differential device). Since this power unit acts as a swing arm, the transmission case and the gear case Rigidity is required (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 60-179525

  However, since the gear case in which the differential device is accommodated becomes large, there is a problem in that weight is increased when the reinforcing rib is provided to ensure rigidity.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a vehicular power unit with enhanced rigidity without increasing the weight.

  In order to solve the above-described problems, a vehicle power unit according to the present invention is mounted on a vehicle (for example, the tricycle 1 in the embodiment) and outputs an internal combustion engine (for example, an engine in the embodiment) that outputs a rotational driving force from a crankshaft. 39), and a transmission device and a differential device for transmitting the rotational driving force of the crankshaft to a drive wheel shaft (for example, the rear wheel shafts 53L and 53R in the embodiment), and is swingably supported by the vehicle body. A transmission case that extends in the vehicle longitudinal direction and accommodates the transmission device, and a gear case that is attached to a rear side portion of the transmission case and accommodates the differential device. Each is provided with a muffler support, and the muffler is attached to these muffler supports.

  In such a vehicle power unit according to the present invention, the transmission case and the gear case have an inclined surface inclined obliquely downward toward the rear on the outer upper surface of the rear portion, and the muffler support portion is provided on the inclined surface. It is preferable.

  Moreover, it is preferable that the muffler support part is provided in the outer side edge part of a transmission case and a gear case.

  Furthermore, it is preferable that the muffler is attached so as to extend in the left-right direction of the vehicle body.

  When the vehicle power unit according to the present invention is configured as described above, a muffler support portion is provided in each of the transmission case and the gear case, and the muffler is attached so as to connect the muffler support portion. It can function as a rigid body that connects the cases. As a result, the rigidity of the entire case can be ensured, so that the number of reinforcing ribs and the like provided in the transmission case and the gear case can be reduced, and the weight of each case can be reduced. Also, compared to the case where the muffler is attached to either the transmission case or the gear case, the space for supporting the muffler can be widened, so that vibration generated on the surface of the muffler can be more effectively suppressed. , Solid propagation sound from the surface of the muffler can be reduced.

  The muffler can be disposed above the inclined surface by providing the outer upper surface of the rear portion of the transmission case and the gear case on an inclined surface inclined obliquely downward toward the rear, and providing a muffler support portion on the inclined surface. Therefore, in addition to simple installation work, the height of the muffler from the ground can be kept low.

  Further, by providing the muffler support portion at the outer end portions of the transmission case and the gear case, the support interval of the muffler can be maximized, and the above-mentioned solid sound can be effectively reduced.

  Furthermore, by arranging the muffler so as to extend in the left-right direction of the vehicle body, there is an advantage that the diameter of the muffler can be increased, and by arranging in this way, the muffler can be improved by the above-described support method. Solid propagation sound due to surface vibration can be effectively reduced.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. First, a motor tricycle 1 on which a vehicle power unit according to the present invention (hereinafter simply referred to as “power unit”) is mounted will be described with reference to FIG. The tricycle 1 having one front wheel 2 and two rear wheels 3L and 3R includes a swing mechanism 6 that connects a front vehicle body 4 having a front wheel 2 and a rear vehicle body 5 having rear wheels 3L and 3R. This is a vehicle in which the rear vehicle body 5 is connected to the front vehicle body 4 in such a manner that it can swing up and down and freely roll left and right.

  The front vehicle body 4 has a vehicle body frame 7 formed in a U shape in a side view, and the front wheels 2 are rotatably attached to a front end portion of the vehicle body frame 7 via a steering mechanism 8. The steering mechanism 8 is attached to the front part of the vehicle body frame 7 and has a head pipe 9 extending in the vertical direction. A steering shaft (not shown) is rotatably attached to the head pipe 9. The front fork 10 is attached to the lower end of the steering shaft, and the front wheel 2 is rotatably attached to the lower end of the front fork 10. On the other hand, a handle post 11 is attached to the upper end of the steering shaft, and a handle 12 is attached to the upper end of the handle post 11. A seat 13 is attached to the upper part of the rear portion of the vehicle body frame 7, and the front wheel 2 is configured to be steerable by operating the handle 12 by a driver riding on the seat 13.

  A front cover 14 is provided in front of the handle 12, and a wind screen 16 including a wiper 15 is attached to the top of the front cover 14. A step floor 17 is provided below the handle 12 and the seat 13. Further, a pair of left and right posts 18 are raised from the rear of the seat 13, a roof 19 is attached to the wind screen 16 and the posts 18, and a luggage compartment 20 is disposed behind the seat 13. A front fender 21 is attached above the front wheel 2 so as to cover the front wheel 2, and a headlamp 22 and a rearview mirror 23 are attached to the front cover 14. A fuel tank 24 is provided below the seat 13 of the front vehicle body 4, and fuel is supplied to a power unit 26 described later by a fuel pump 25 provided in the fuel tank 24.

  The rear vehicle body 5 is provided with a power unit 26 that drives the rear wheels 3L and 3R. An intake device 27 and an exhaust device 30 having a catalyst pipe 28 and a muffler 29 are attached to the power unit 26, and the whole is covered with an engine cover 31. Details of the power unit 26 will be described later.

  The swing mechanism 6 includes a link 32 and a joint case 33. The link 32 extending downward from the lower portion of the body frame 7 is attached to the body frame 7 so as to be swingable in a predetermined angle range in the front-rear direction. Further, a joint case 33 extending rearward is attached to the lower end portion of the link 32 so as to be swingable in the vertical direction with respect to the link 32.

  The joint case 33 has one end pivotally connected to the link 32 and a case main body 33a inserted into the other end of the case main body 33a. The joint shaft 33b is attached so as to be relatively rotatable, and the bracket 33c is connected to the joint shaft 33b and the lower portion of the power unit 26. The joint case 33 is supported by a cushion 34 having one end pivotally connected to the rear portion of the vehicle body frame 7 and the other end pivotally connected to the case main body 33 a of the joint case 33. The damper 33d has a plurality of columnar rubbers interposed between the plurality of pressing members extending in the radial direction from the joint shaft 33b and the case body 33a, and the rubber is formed by relative rotation between the pressing members and the case body 33a. It is a so-called “Nighthard damper” that exerts a damper action by being compressed.

  Now, the power unit 26 will be described with reference to FIGS. In this embodiment, the direction of the arrow F in FIG. 2 is assumed to be the front and the direction of the arrow U is assumed to be the upper side. The power unit 26 includes an engine 39 including a cylinder head 40 and an engine case 41, a transmission device 57 stored in the transmission case 42, and a differential device 63 stored in a gear case 68.

  The engine case 41 is formed with a cylinder chamber 43a surrounded by a cylinder sleeve 43 that is fitted so as to extend in the longitudinal direction of the vehicle body. A piston 44 is arranged in the cylinder chamber 43a so as to be slidable in the longitudinal direction. It is installed. Further, the piston 44 is connected via a connecting rod 45 to a crankshaft 46 that is rotatably held by the engine case 41. An intake port and an exhaust port formed in the cylinder head 40 communicate with the combustion chamber 47 formed by the cylinder sleeve 43, the cylinder head 40 and the piston 44.

  The crankshaft 46 attached to the engine case 41 so as to extend in the left-right direction of the vehicle body is composed of a left crankshaft half 46L and a right crankshaft half 46R, and connects both the crankshaft halves 46L and 46R. A connecting rod 45 is connected via the arranged crank pin 50. The crankshaft halves 46L and 46R are held in the engine case 41 via left and right bearings 51 and 52.

  The cylinder head 40 is rotatably provided with a cam shaft 73 on which cams for opening and closing the intake valve and the exhaust valve are formed. A cam driven gear 74 is attached to the cam shaft 73. On the other hand, a cam drive gear 75 is attached to a position of the crankshaft 46 facing the cam driven gear 74, and a cam chain 76 is wound around these gears 74 and 75. Therefore, when the crankshaft 46 rotates, the rotation of the cam drive gear 75 is transmitted to the cam driven gear 74 via the cam chain 76, the camshaft 73 rotates, and the intake valve and the exhaust valve open and close.

  A transmission case 42 is attached to the left side of the engine case 41, and the journal portion of the left crankshaft half 46 </ b> L is disposed so as to protrude into the transmission case 42. The transmission case 42 is provided with a rear wheel shaft 53 that is positioned behind the crankshaft 46 and extends in parallel with the crankshaft 46 and is rotatably held by the transmission case 42. A counter shaft 54 that extends in parallel with the shaft 46 and is rotatably held by the transmission case 42 is attached.

  A left cover member 55 is attached to the left side surface of the transmission case 42, and a transmission device (transmission device) 57 is stored in a transmission device chamber 56 surrounded by the transmission case 42 and the left cover member 55. ing. The transmission device 57 is attached to the journal portion of the left crankshaft half 46 </ b> L extending into the transmission device chamber 56 and rotates integrally therewith, and is attached to the left end portion of the counter shaft 54. A driven pulley 59 that rotates, is attached to a substantially central portion of the countershaft 54, is wound around a clutch 60 that engages and disengages the driven pulley 59 and the countershaft 54, and a drive pulley 58 that is wound around the drive pulley 58 and the driven pulley 59. The V belt 61 transmits this rotation to the driven pulley 59.

  The drive pulley 58 is a fixed pulley half 58a attached to the journal portion of the left crankshaft half 46L so as to rotate integrally therewith, and is relatively movable in the axial direction with respect to the fixed pulley half 58a, and the left crankshaft half The body 46L and a movable pulley half 58b that can rotate integrally with the body 46L. The V-belt 61 is sandwiched between the fixed and movable pulley halves 58a and 58b. On the other hand, the driven pulley 59 is a fixed pulley half 59a attached to the counter shaft 54 so as to be rotatable relative to the counter shaft 54. The driven pulley 59 is relatively movable in the axial direction with respect to the fixed pulley half 59a and is relatively rotated with respect to the counter shaft 54. The V-belt 61 is sandwiched between the fixed and movable pulley halves 59a and 59b. Therefore, by variably setting the pulley widths of the drive pulley 58 and the driven pulley 59, the winding radius of the V-belt 61 around both the pulleys 58 and 59 is continuously changed to continuously change the transmission ratio (continuously). Can be controlled.

  The transmission case 42 extends rearward from the engine case 41, and a gear case 68 is attached to the right side portion of the transmission case 42 behind the engine case 41, and is surrounded by the transmission case 42 and the gear case 68. A reduction gear train 88 and a differential device 63 are stored in the chia chamber 89. An idle shaft 62 is attached between the counter shaft 54 and the rear wheel shaft 53 and extends in substantially parallel to the shafts 54 and 53 in the gear chamber 89. The counter shaft 54 and the rear wheel shaft 53 extend into the gear chamber 89, and a reduction gear train 88 is disposed on the counter shaft 54, the idle shaft 62, and the rear wheel shaft 53. Therefore, the drive pulley 58 is rotated by the rotation of the crankshaft 46, the rotation is transmitted to the driven pulley 59 via the V belt 61, and further transmitted from the clutch 60 to the counter shaft 54.

  The rear wheel shaft 53 is composed of a left rear wheel shaft 53L whose left end is connected to the left rear wheel 3L and a right rear wheel shaft 53R whose right end is connected to the right rear wheel 3R. 53L and 53R are connected to a differential device 63 disposed in the gear case 68. The differential device 63 includes a differential carrier 64 disposed coaxially with the rear wheel shaft 53 so as to be rotatable relative to the rear wheel shaft 53, and a pinion shaft supported through the differential carrier 64 in a direction perpendicular to the rear wheel shaft 53. 65, a pair of pinion gears 66 attached to both ends of the pinion shaft 65, and a pair of left and right side gears 67 meshing with both pinion gears 66. The left and right rear wheel shafts 53L and 53R are respectively connected to the left and right side gears 67. It is connected. Then, the rotation transmitted from the counter shaft 54 via the idle shaft 62 by the reduction gear train 88 is input to the differential carrier 64 of the differential device 63, and the side gear 67 via the pinion shaft 65 and both pinion gears 66. The left and right rear wheels 3L and 3R attached to the rear wheel shafts 53L and 53R are rotationally driven.

  A kick start mechanism 69 for starting the engine 39 is stored in the front portion of the transmission case 42. The kick starting mechanism 69 includes a kick shaft 70 and an idle shaft 71 extending substantially parallel to the crank shaft 46, and a kick gear train 72 disposed on the kick shaft 70, the idle shaft 71 and the crank shaft 46. A kick pedal (not shown) is attached to the tip of the kick shaft 70. When the driver of the motor tricycle 1 kicks out the kick pedal and rotates the kick shaft 70, the rotation is caused by the idle shaft 71 and the kick gear train. The engine 39 is configured to start by being transmitted to the crankshaft 46 via 72.

  A radiator case 82 is attached to the right side portion of the engine case 41, and a radiator 83 is attached to the front portion of the radiator case 82. Cooling water circulates and cools the cylinder head 40 and the engine case 41 by the cooling water pump 77 and the thermostat 78 provided in the crankcase 42, and the running air is applied to the radiator 83 so that the heat of the cooling water is dissipated. It is configured. On the other hand, a generator 79 and a cooling fan 80 are attached to the tip of the right crankshaft half 46R. Therefore, power is generated by the generator 79 by the rotation of the crankshaft 46, and the air that has passed through the radiator 83 is guided to the cooling fan 80 through the radiator case 82, and sent by the cooling fan 80 in the front-rear and vertical directions. The inside of the power unit 26 can be efficiently cooled.

  A muffler 29 formed in a cylindrical shape is attached to the outer upper surface of the rear end portion of the power unit 26. Two mounting members 90 a and 90 b are attached to the circumferential surface of the muffler 29 so as to extend in the left-right direction so as to be substantially parallel to the top and bottom. On the other hand, on the outer upper surface of the rear end portion of the power unit 26 to which the muffler 29 is attached, that is, the outer upper surface of the rear end portions of the transmission case 42 and the gear case 68, an inclined surface 91 that is inclined obliquely downward toward the rear is formed. Has been. Muffler support portions 92 and 93 extending rearward and obliquely upward from each of the transmission case 42 and the gear case 68 are formed on the inclined surface 91. The muffler 29 is arranged so that its cylindrical shaft extends and extends in the left-right direction of the vehicle body, and the mounting members 90a and 90b are arranged in the power unit 26 so as to extend obliquely downward and rearward of the muffler 29 in a side view. Yes. Then, with the spacers 94a and 94b inserted between the two attachment members 90a and 90b, bolts 95 and 95 are inserted so as to penetrate the attachment members 90a and 90b and the spacers 94a and 94b. The muffler 29 is fixed to the power unit 26 by fastening to the support portions 92 and 93.

  Thus, the muffler support portions 92 and 93 are provided in the transmission case 42 and the gear case 60, respectively, and the muffler 29 is attached so as to connect the muffler support portions 92 and 93, so that the muffler 29 is connected to the transmission case 42 and the gear case. 60 can function as a rigid body connecting the two. Thereby, since the rigidity of the whole case can be ensured, the reinforcing ribs etc. provided in these cases 42 and 60 can be reduced, and the weight of each case 42 and 60 can be reduced. Further, compared to the case where the muffler 29 is attached to either the transmission case 42 or the gear case 60, the space for supporting the muffler 29 can be widened, so that vibration generated on the surface of the muffler 29 is more effective. The solid-borne sound from the surface of the muffler 29 can be reduced. In particular, by providing these muffler support portions 92 and 93 outside the rear end portions of the transmission case 42 and the gear case 60, the support interval of the muffler can be maximized, and the above-mentioned solid sound is effectively reduced. can do.

  As shown in the present embodiment, the muffler 29 can be disposed above the inclined surface 91 by attaching the muffler 29 to the inclined surface 91 at the rear ends of the transmission case 42 and the gear case 60. In addition to simplifying the mounting operation, the height of the muffler 29 from the ground can be kept low. Moreover, there is an advantage that the diameter of the muffler 29 can be increased by arranging the muffler 29 so that the cylindrical axis direction of the muffler 29 extends in the left-right direction of the vehicle body as described above. Moreover, by arranging in this way, solid propagation sound due to vibration of the surface of the muffler 29 can be effectively reduced by the above-described support method. In the embodiment, the engine case 41 and the transmission case 42 are configured separately, but the engine case and the transmission case may be configured integrally.

It is a left side view showing a tricycle equipped with a power unit according to the present invention. It is a left side view of the power unit. It is a top view of the power unit. It is the perspective view which looked at the power unit from the rear.

Explanation of symbols

1 Auto tricycle (vehicle)
26 Power unit 29 Muffler 39 Engine (internal combustion engine)
42 Transmission case 46 Crankshaft 57 Transmission device 63 Differential device 68 Gear case 91 Inclined surfaces 92 and 93 Muffler support

Claims (4)

An internal combustion engine that is mounted on a vehicle and outputs a rotational driving force from a crankshaft, and a transmission device and a differential device that transmit the rotational driving force of the crankshaft to a driving wheel shaft, are swingable on the vehicle body A vehicle power unit to be supported,
A transmission case extending in the longitudinal direction of the vehicle and accommodating the transmission device;
A gear case that is attached to a rear side portion of the transmission case and accommodates the differential;
A vehicle power unit in which a muffler support portion is provided in each of the transmission case and the gear case, and the muffler is attached to the muffler support portion. The transmission case and the gear case have an inclined surface inclined obliquely downward toward the rear on the outer upper surface of the rear part,
The vehicle power unit according to claim 1, wherein the muffler support portion is provided on the inclined surface.   The power unit for vehicles according to claim 1 or 2 with which said muffler support part is provided in the outside end of said power transmission case and said gear case.   The vehicle power unit according to any one of claims 1 to 3, wherein the muffler is attached so as to extend in a lateral direction of the vehicle body.

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