POWER UNIT

Abstract

A power unit provided with a dry sump type lubricating device includes a power unit case that is covered in part by a power unit case cover and is divided into a front unit case and a rear unit case. The power unit also includes a crankshaft rotatably supported by a crank chamber that is formed by the power unit case and a shift shaft rotatably supported by a transmission chamber that is provided adjacent to the crank chamber. The power unit also includes an oil tank disposed on the crank chamber side of an anteroposterior outside surface of the power unit case cover and a hydraulic control device for controlling a shift clutch, disposed on the transmission chamber side of the anteroposterior outside surface of the power unit case cover.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the present invention will be described with reference to the accompanying drawings, wherein:

FIG. 1 is a side view illustrating an all terrain vehicle mounted with a power unit thereon according to an embodiment of the invention with its body cover and the like removed;

FIG. 2 is a plan view of the all terrain vehicle;

FIG. 3 is a front view of the power unit with the internal combustion engine partially removed;

FIG. 4 is a cross-sectional view of a portion of the internal combustion engine;

FIG. 5 is a front view of a front unit case;

FIG. 6 is a front view of a unit case cover;

FIG. 7 is a cross-sectional view of the unit case cover taken along line VII-VII of FIG. 6;

FIG. 8 is a front view of a portion of the power unit; and

FIG. 9 is a combined cross-sectional view approximately taken along lines IX-IX and IX′-IX′ of FIG. 8.

Claims

1. A power unit provided with a dry sump type lubricating device, said power unit comprising: a power unit case divided into a front unit case and a rear unit case,a power unit case cover that covers at least one of said front unit case and said rear unit case;a crank chamber formed by said power unit case;a crankshaft rotatably supported by said crank chamber;a transmission chamber disposed adjacent to said crank chamber;a shift shaft rotatably supported by said transmission chamber;an oil tank disposed on the crank chamber side of an anteroposterior outside surface of said power unit case cover; anda hydraulic control device for controlling a shift clutch, provided on said transmission chamber side of the anteroposterior outside surface of said power unit case cover.

2. The power unit according to claim 1, wherein; said oil tank extends from a lower end of said power unit case cover to an upper end of said power unit case cover; anda shift motor for shifting a shift gear of the shift shaft is disposed on said power unit case cover, wherein said shift motor is surrounded by said oil tank, said hydraulic control device and an output shaft projecting from said transmission chamber.

3. The power unit according to claim 1, wherein: said power unit case is split into said front unit case and said rear unit case at a plane perpendicular to said crankshaft, andsaid crankshaft extends through a central axis of a cylinder bore included in a cylinder block.

4. The power unit according to claim 1, wherein said oil tank is formed in said power unit case cover.

5. The power unit according to claim 1, further comprising: a spacer connecting said front unit case to said power unit case cover, wherein said spacer is disposed between said front unit case and said power unit case cover.

6. The power unit according to claim 1, further comprising: an oil pump unit attached to a front mating surface of said front case unit, whereinsaid oil pump unit includes a partition wall provided between a front oil pump case and a rear oil pump case and at least one oil passage is formed in said partition wall.

7. The power unit according to claim 6, wherein: a pump drive shaft passes through said front oil pump case, said partition wall, said rear oil pump case and said front unit case, andsaid pump drive shaft is connected to a balancer shaft.

8. A power unit provided with a dry sump type lubricating device, said power unit comprising: a power unit case divided into a front unit case and a rear unit case,a power unit case cover that covers at least one of said front unit case and said rear unit case;a crank chamber formed by said power unit case;a crankshaft rotatably supported by said crank chamber;a transmission chamber disposed adjacent to said crank chamber;a shift shaft rotatably supported by said transmission chamber;an oil tank disposed on the crank chamber side of an anteroposterior outside surface of said power unit case cover;a hydraulic control device for controlling a shift clutch, provided on said transmission chamber side of the anteroposterior outside surface of said power unit case cover;an oil pump unit attached to a front mating surface of said front case unit, wherein said oil pump unit includes a partition wall provided between a front oil pump case and a rear oil pump case and at least one oil passage is formed in said partition wall, anda pump drive shaft that passes through said front oil pump case, said partition wall, said rear oil pump case and said front unit case, wherein said pump drive shaft is connected to a balancer shaft.