Abstract
The present invention relates to a small four-stroke gasoline engine
with oil mist lubrication. The lubrication oil way of the engine includes
a crankshaft chamber B, a camshaft chamber C, an upper rocker arm
chamber D and a condensation chamber E. The camshaft chamber C communicates
with the upper rocker arm chamber D via a tappet cavity 13. The upper
rocker arm chamber D communicates with the condensation chamber E.
An oil mist chamber A is surrounded by an upper case body 3 and a
lower case body 4 at the side of the crankshaft chamber B, the bottom
of the oil mist chamber A communicates with the crankshaft chamber
B. An oilsplash impeller 2 is fixed on a crankshaft, which extends
into the oil mist chamber A. An oil way 12 is provided on the upper
case body 3 between the oil mist chamber A and the camshaft chamber
C. An oil return way 15 is provided on a cylinder head assembly 5.
An oil return way 14 is provided on the upper case body 3. An upper
interface of the oil return way 15 communicates with the upper rocker
arm chamber D, a lower interface of the oil return way 15 communicates
with the oil return way 14, and a lower interface of the oil return
way 14 communicates with the crankshaft chamber B. The conventional
lubricating mode is changed by the structure of the invention, which
makes use of the pressure change during the reciprocating movement
of a piston assembly 8 to attain the circulation of oil. The structure
is simple, reliable in operation and has small consumption in power.
Claims
1. A small four-stroke gasoline engine with oil mist lubrication comprising:
an upper case body 3 and a lower case body 4, a crankshaft assembly
1, a piston assembly 8, a cylinder head assembly 5, a cylinder head
cover 6 and a lubrication oil way of engine, and the lubrication oil
way of engine includes a crankshaft chamber B, a camshaft chamber
C, an upper rocker arm chamber D and a condensation chamber E, and
the camshaft chamber C is connected to the upper rocker arm chamber
D via a tappet cavity 13, and the upper rocker arm chamber D communicates
with the condensation chamber E, wherein an oil mist chamber A is
formed by an upper case body 3 and a lower case body 4 on one side
of the crankshaft chamber B, and the bottom of the oil mist chamber
A communicates with the crankshaft chamber B, an oilsplash impeller
2 is fixed onto the crankshaft which extends into the oil mist chamber
A, an oil way 12 is provided on the upper case body 3 which is in
between the oil mist chamber A and the camshaft chamber C, an oil
return way 15 is provided on a cylinder head assembly 5, an oil return
way 14 is provided on the upper case body 3, and the upper interface
of the oil return way 15 communicates with the upper rocker arm chamber
D, and its lower interface is connected to the oil return way 14,
and the lower interface of the oil return way 14 communicates with
the crankshaft chamber B.
2. The small four-stroke gasoline engine with oil mist lubrication
as in claim 1, wherein a reed valve 7 is provided at the interface
of cylinder head assembly 5 between the oil return way 15 and the
oil return way 14.
3. The small four-stroke gasoline engine with oil mist lubrication
as in claim 2, wherein a spacing plate 11 is provided on the reed
valve 7.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a gasoline engine and more
particularly pertains to a small four-stroke gasoline engine with
improvements on its lubricant passage ways and its mode of lubrication.
[0002] It is known that existing small four-stroke gasoline engines
apply splashing lubrication in conjunction with pressure oil injection
as its mode of lubrication, that is, to splash or make use of pressure
to spread lubricants onto the surfaces of parts for lubrication.
This mode is characterized in that it is required to dispose on
the machine the structures of the lubricant pumps and splashing
devices, which are relatively complicated. While the lubricating
effects are general, there are dead angles and power consumption
is large.
BRIEF SUMMARY OF THE INVENTION
[0003] In view of the aforesaid disadvantages now present in the
prior art, the present invention provides a small four-stroke gasoline
engine with oil mist lubrication which is reasonably simple in construction
and capable of lubricating every part by making use of the better
mobility of oil mists.
[0004] To attain this, the present invention generally comprises
an upper and a lower case bodies, a crankshaft assembly, a piston
assembly, a cylinder head assembly, a cylinder head cover and a
lubrication oil way of engine. The lubrication oil way of engine
includes a crankshaft chamber, a camshaft chamber, an upper rocker
arm chamber and a condensation chamber. The camshaft chamber is
connected to the upper rocker arm chamber via a tappet cavity. The
upper rocker arm chamber communicates with the condensation chamber.
An oil mist chamber is formed by an upper case body and a lower
case body on one side of the crankshaft chamber. The bottom of the
oil mist chamber communicates with the crankshaft chamber. An oilsplash
impeller is fixed onto the crankshaft which extends into the oil
mist chamber. An oil way is provided on the upper case body which
is in between the oil mist chamber and the camshaft chamber. An
oil return way is provided on the cylinder head assembly. An oil
return way is provided on the upper case body. The upper interface
of the cylinder head oil return way communicates with the upper
rocker arm chamber, and its lower interface is connected to the
oil return way of the upper case body. The lower interface of the
oil return way of the upper case body communicates with the crankshaft
chamber.
[0005] To make the lubricating oil mists circulate in the lubrication
oil way of engine following the pressure changes generated by the
up and down movements of the piston assembly, a reed valve is provided
at the interface of the cylinder head assembly between the oil return
way of the cylinder head and the oil return way of the upper case
body.
[0006] To ensure reliable circulation of the lubricating oil mists
in the lubrication oil way of engine, a spacing plate is provided
on the reed valve.
[0007] By means of the aforesaid construction, the oilsplash impeller
rotates with the crankshaft, causing the lubricant in the oil mist
chamber to produce lubricating oil mists. The lubricating oil mists
circulate in the lubrication oil way of engine resulting from the
pressure changes generated by the up and down movements of the piston
assembly. The engine is capable of lubricating every part in it
by making use of the better mobility of oil mists.
[0008] It is an object of the present invention to provide a small
four-stroke gasoline engine with oil mist lubrication which is of
simple construction, reliable and even lubrication, small power
consumption, low production cost and stable product quality and
so forth, thereby overcoming the disadvantages of the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 shows the construction of the present invention.
[0010] FIG. 2 shows the cross-sectional view as taken along the
line A-A of FIG. 1.
[0011] FIG. 3 shows the bottom view of the cylinder head assembly
of FIG. 1.
[0012] FIG. 4 shows the cross-sectional view as taken along the
line B-B of FIG. 3.
DETAILED DESCRIPTION OF THE INVENTION
[0013] The present invention is further described in detail with
the following embodiment and the accompanying drawings. As illustrated
in FIGS. 1 to 4, the embodiment is a small four-stroke gasoline
engine with oil mist lubrication, which comprises an upper case
body 3, a lower case body 4, a crankshaft assembly 1, a piston assembly
8, a cylinder head assembly 5, a cylinder head cover 6 and a lubrication
oil way of engine. The lubrication oil way of engine includes a
crankshaft chamber B, a camshaft chamber C, an upper rocker arm
chamber D and a condensation chamber E. The camshaft chamber C is
connected to the upper rocker arm chamber D via a tappet cavity
13. The upper rocker arm chamber D communicates with the condensation
chamber E. The condensation chamber E is a long and narrow space,
the functions of which are to provide space for oil mists to condense
and for the convenience of their backflow. Further, by means of
communicating an air pipe 9 with an air intake pipe 10, the pressure
therein can be balanced. An oil mist chamber A is formed by an upper
case body 3 and a lower case body 4 on one side of the crankshaft
chamber A. The bottom of the oil mist chamber A communicates with
the crankshaft chamber B. An oilsplash impeller 2 is fixed onto
the crankshaft which extends into the oil mist chamber A. An oil
way 12 is provided on the upper case body 3 which is in between
the oil mist chamber A and the camshaft chamber C. An oil return
way 15 is provided on the cylinder head assembly 5. An oil return
way 14 is provided on the upper case body 3. The upper interface
of the cylinder head oil return way 15 communicates with the upper
rocker arm chamber D, and its lower interface is connected to the
oil return way of the upper case body 14. The lower interface of
the oil return way of the upper case body 14 communicates with the
crankshaft chamber B. A reed valve 7 is provided at the interface
of the cylinder head assembly 5 between the oil return way of the
cylinder head 15 and the oil return way of the upper case body 14.
To ensure reliable operation of the reed valve 7, a spacing plate
11 is provided at the bottom of the reed valve 7.
[0014] For the sake of conveniently describing the working process
of the circulation of the lubricating oil mists in the lubrication
oil way of engine when the present invention is in operation, the
pressure of each chamber is assumed as follows: the pressure of
the condensation chamber E--P0, the pressure of the camshaft chamber
C--P1, the pressure of the upper rocker arm chamber D--P2, the pressure
of the crankshaft chamber B--P3, and the pressure of the oil mist
chamber A--P4. When the present invention is in operation, the oilsplash
impeller 2 provided on the crankshaft assembly 1 rotates with the
crankshaft, thereby swirling the lubricant at the bottom of the
oil mist chamber A to form oil mists dispersing in the oil mist
chamber A. By means of opening or closing the reed valve 7 provided
at the bottom of the cylinder head assembly 5, according to the
pressure changes at each chamber, the circulating direction of the
lubrication oil way can be controlled.
[0015] When the piston assembly 8 moves downwards, the pressure
of the crankshaft chamber B P3 increases, and the relationship of
each chamber's pressure is P3>P4>P1>P2>P0. The oil mists
pass through the upper case body oil way 12 and enter from the oil
mist chamber A into the camshaft chamber C. The oil mists of the
camshaft chamber C enter via the tappet cavity 13 into the upper
rocker arm chamber D. The oil mists of the upper rocker arm chamber
D enter the condensation chamber E. The oil mist direction of the
oil way is shown in FIG. 1 by the arrow heads therein. At this point
of time, the reed valve 7 is in a closed state.
[0016] When the piston assembly 8 moves upwards, the pressure of
the crankshaft chamber B P3 decreases, and the relationship of each
chamber's pressure is P3<P4<P1<P2<P0, which is opposite
to the relationship when the piston assembly 8 moves downwards.
At this point of time, the reed valve 7 is in an open state under
the pressure effect, thereby absorbing the lubricant condensed inside
the condensation chamber E via the cylinder head oil return way
15, the reed valve 7 and the upper case body oil return way 14 back
to the crankshaft chamber B, and via the communication at the bottom
the lubricant then returns to the oil mist chamber A. The direction
of the oil way backflow is shown in FIG. 2 by the arrow heads therein.
The circulation process of the oil mist lubrication is therefore
completed.
[0017] In conclusion, the present invention changes the conventional
lubricating mode fundamentally. The oil mist lubrication is used
for the whole system, which makes use of the pressure changes generated
by the up and down movements of the piston assembly 8 to attain
the circulation of the oil way. The structure is simple and reliable.
Each part can be evenly lubricated without any dead angle. |