JPS62178705A - Oil pump fitting structure of engine - Google Patents

Abstract

PURPOSE:To use a shroud also as a pump cover and to eliminate the need of a pump cover by disposing an oil pump in the shroud for a cylinder and a cooling air blowing fan. CONSTITUTION:A worm gear 26 is provided on a crankshaft 18 of an engine, and a cooling air blowing fan 34 is mounted on a rotor 30b of a generator on the outside of the crankshaft. A shroud 40 made of resin covers the outside of the cooling air blowing fan 34. The shroud 40 comprises a side shroud 40a extending from its periphery upward to the side of a cylinder 15, an upper shroud 40b extending from the upper part of the side shroud 40a in the direction of a width for covering above the cylinder 15. A driving shaft 45a of an oil pump 45 is engaged with the worm gear 26 of the crankshaft 18, and disposed between the cylinder 15 and the cooling air blowing fan 34 in a space in the shroud.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an oil pump mounting structure for an engine that drives small vehicles such as scooters and tricycles.

[Conventional technology]

In this type of engine, the oil pump that supplies lubricating oil to the engine is generally driven using power from the crankshaft. It is configured to extract power from the crankshaft by meshing a worm provided on the crankshaft with a worm wheel provided on the drive shaft of the pump, which faces through a mounting hole provided in the crankcase.

[Problem that the invention seeks to solve]

However, with this structure, it is necessary to attach a pump cover to the outside of the oil pump to protect the pump, which not only increases the number of parts but also increases the size of the engine.

[Means for solving problems]

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an oil pump mounting structure for an engine that can be miniaturized. In the oil pump mounting structure according to the present invention, the oil pump is disposed within a shroud that covers the outside of the engine and between a cylinder and a cooling fan.

[Effect]

In the present invention, by utilizing the gap between the cylinder and the cooling fan, the shroud also serves as the pump cover, making the pump cover unnecessary.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an exploded sectional view showing a drive unit in which an engine oil pump mounting structure according to the present invention is implemented, and FIG. 2 is a sectional view taken along line nn in FIG.
The symbol indicated by the symbol indicates a drive unit. This drive unit
In order to function as a component of the suspension system for the rear wheel 2, the engine 10 is pivotally supported on a frame of a motorcycle (not shown) so as to be able to swing vertically.
, a power transmission mechanism 12 equipped with a chain 11 that transmits the power of this engine 10 to the rear, and this power transmission mechanism 1
2 and supports the rear wheel shaft 13 at the rear.
It is composed of.

That is, the engine 10, the power transmission mechanism 12, and the rear wheel shaft 13 are integrally held by the transmission case 14.

The engine IO is a crank chamber precompression type air-cooled two-stroke engine, and a cylinder 15 having cooling fins is disposed in a substantially vertical direction immediately in front of the rear wheel 2. 1
6 is a piston held in the cylinder 15 so as to be able to rise and fall;
It is connected to the crank bin by a connecting rod 17. 18
2 is a crankshaft that rotates forward, clockwise in FIG. 2, as the piston 16 moves up and down. 19 is a crank case defining a crank chamber, and a partition wall 20a.

Right and left crankcases 19a having 20b.

It is divided into 19b. The crankshaft 18 is mounted in the vehicle width direction via bearings 22 and 22 that are press-fitted and fixed to the cylindrical portions 21a and 21b provided on the partition wall. Reference numeral 23 denotes an exhaust pipe extending obliquely downward from the front surface of the cylinder 15 for discharging exhaust gas in the same direction as the rotational direction of the crankshaft 18.

25 is an annular rib formed integrally with the crankcase 19 on the outside of the partition wall 20a, and on the crankshaft 18 located inside this rib 25, the power of the crankshaft 18 is taken out to drive an oil pump to be described later. A worm 26 made of resin is mounted on the shaft. This worm 26 is connected in the circumferential direction by a pin 27 fitted to the crankshaft 18,
Axial movement is prevented by retaining rings 28,29. A fixing plate 31 to which a stator 30a of a generator 30 is attached is attached to the outside of the rib 25 so as to close the open end of the rib 25. 30b is a rotor disposed to cover the stator 30a, and this rotor 30b is fixed with a rivet 33 to a boss 32 keyed to the tip of the crankshaft 18, and a cooling air blower is provided on the outside. fan 34
is attached with mounting screws 35.

A resin shroud 40 covers the outside of the cooling fan 34 and forms an air guide path, and includes a side shroud 40a extending upward from around the cooling fan 34 to the side of the cylinder 15; An upper shroud 40b extends from the upper part of the side shroud 40a in the vehicle width direction and covers the upper part of the cylinder 15. The side shroud 40a has an air intake port 41 at a portion facing the cooling fan 34, and the upper shroud 40b has an exhaust port 42 opened toward the rear and downward.

45 is a space inside the shroud 40 and the cylinder 1
5 and the cooling fan 34 for separate oil supply, and a worm wheel 46 that meshes with the worm 26 is mounted on the tip of the drive shaft 45a. The oil pump 45 is disposed at a position displaced to the front side of the crankshaft 18 so as not to block the cooling air generated clockwise in FIG. 2 by the cooling fan 34. Further, the arrangement direction is parallel to the axis of the cylinder 15.

Therefore, the oil pump 45 extends in the cylinder direction,
It does not protrude outward from the engine 10.

That is, 47 is a mounting part for assembling the oil pump 45 in a direction parallel to the axis of the cylinder 15, and is integrally formed on the upper front side of the rib 25, and is for mounting so that the tip of the oil pump 45 faces inside the rib 25. A hole 48 is bored in a direction parallel to the axis of the cylinder 15. In other words, the oil pump 45 is assembled in a direction perpendicular to the crankshaft 18. Here, since the machining direction of the attachment hole 48 is parallel to the axis of the cylinder 15, the machining can be easily performed without using any special machining equipment.

Reference numeral 50 denotes a suction hose connected to the suction side of the oil pump 45, which is connected to an oil tank (not shown), and is housed and held in a holding groove 51 formed integrally with the upper shroud 40b. A discharge hose 52 is connected to the discharge side of the oil pump 45, and is connected to a carburetor 53 attached to the back of the cylinder 15. Here, the oil pump 45 of these suction hose 50 and discharge hose 52
The portions adjacent to are housed and protected within the upper shroud 40b.

Further, a drive sprocket 55 to which a chain 11 is attached is rotatably supported on the left side of the crankshaft 18, and a wet centrifugal clutch 56 that connects this sprocket 55 to the crankshaft 18 by centrifugal force is spline-coupled at the tip. has been done. 57 is a driven shaft connected to the chain 11 via a driven sprocket 58. Between this driven shaft 57 and the rear wheel shaft 13 is a gear train 59 that decelerates the rotation of the driven shaft 57 and transmits it to the rear wheel shaft 13. It has been intervened.

In the engine oil pump mounting structure configured in this way, when the engine 10 is started, the crankshaft 1
8 rotates, and the power of this crankshaft 18 is transmitted to the worm 26.
It is transmitted to the drive shaft 45a of the oil pump 45 via the worm wheel 46 meshed with the worm wheel 46. Therefore, the oil pump 45 is driven and can suck lubricating oil from a tank (not shown) and supply it to the carburetor 53.

Furthermore, since the oil pump 45 is disposed within the shroud 40 between the cylinder 15 and the cooling fan 34, the shroud 40 can also function as a pump cover that covers the oil pump 45. In other words, the shroud 40 also serves as a pump cover, making it possible to eliminate the need for a pump cover that was conventionally attached to the outside of the engine.

In the embodiment, since the oil pump 45 is arranged in a direction parallel to the axis of the cylinder 15, the oil pump 45
5 can be accommodated within the side view shape of the drive unit 1 without protruding to the front side of the cylinder 15. Thereby, the length of the drive unit 1 in the front-rear direction can be shortened.

countersunk 6, rib 25 for installing oil pump 45
is formed integrally with the crankcase 19, and the mounting hole 48 is bored in a direction parallel to the axis of the cylinder 15.
The mounting portion 47 of the oil pump 45 can be easily processed without the need for special processing.

〔Effect of the invention〕

As explained above, according to the present invention, since the oil pump is disposed within the shroud that covers the outside of the engine and utilizes the gap between the cylinder and the cooling fan, the shroud also serves as a pump cover. This eliminates the need for a pump cover.

Therefore, the number of parts can be reduced, and since the pump cover does not protrude outside the engine as in the conventional case, the engine can be made smaller. There is also the advantage that the space within the shroud can be used effectively.

[Brief explanation of drawings]

FIG. 1 is an exploded sectional view showing a drive unit in which the engine oil pump mounting structure according to the present invention is implemented;
The figure is a sectional view taken along the line ■--■ in FIG. 10...Engine, 15...Cylinder, 18...
... Crankshaft, 19 ... Crank case, 25
... Rib, 26 ... Worm, 34 ... Cooling fan, 40 ... Shroud, 45 ...
Oil pump, 46...worm, wheel.

Claims (1)

[Claims] An oil pump mounting structure for an engine in which a cooling fan is provided on a crankshaft and the outside of the fan is covered with a shroud, and an oil pump is disposed within the shroud between a cylinder and the cooling fan.