Lubricant structure of closed-type transmission compressor

A closed-type transmission compressor comprises an upper shell having a compressing unit and a lower shell having a transmission unit. The transmission unit includes a stator which generates magnetic power, a rotor rotated by the magnetic power of the stator, and a crankshaft rotated by rotation of the rotor. The compressing unit includes a slider changing rotatory movement of the crankshaft into linear movement, a piston attached to the slider and reciprocating in a cylinder, a head cover covering the cylinder, an inlet valve between a head and a head cover which permits intake of a refrigerant gas, an outlet valve between the head and the head cover which permits exhaust of the refrigerant gas, a propeller conveying oil in the lower shell into the crankshaft, and a screw-shaped oil path groove formed in the inside of crankshaft along which the oil is flowed.

BACKGROUND OF THE INVENTION 
The present invention relates to a closed-type transmission compressor, 
more particularly, to a lubricant structure in a closed-type transmission 
compressor which provide enough lubricating oil to a part which requires 
lubricating oil (hereinafter referred as the lubricating part). 
A conventional closed-type transmission compressor includes, as shown in 
FIG. 1, an upper shell 1 having a compressing unit and a lower shell 2 
having a transmission unit, in which the transmission device part includes 
a stator 4 attached to a frame 3 by using bolts for providing magnetic 
power, a rotor 5 rotating by the magnetic power of the stator 4, and a 
crankshaft 6 rotating by rotation of the rotor 5. The compressing unit 
includes a slider 7 changing the rotatory movement of the crankshaft 6 
into linear movement, a piston 8 attached to the slider 7 and 
reciprocating in a cylinder 9, a head cover 10 covering the cylinder 9, an 
inlet valve 11 between head 10 and the head cover 10 which permits intake 
of a refrigerant gas, an outlet valve 12 between the head 10 and the head 
cover 13 which permits exhaust of the refrigerant gas, and a propeller 14 
dispersing oil 15 in the lower shell 2 into the crankshaft 6. 
By applying electricity to the compressor, the rotor 5 is rotated by an 
induced current occurring between the stator 4 and rotor 5, therefore the 
crankshaft 6 attached to the rotor 5 is rotated. The rotatory movement of 
the crankshaft 6 is changed into linear movement by the slider 7, whereby 
the piston 8 reciprocates in the cylinder 9. 
On the other hand, propeller 14 provided on a lower side of the crankshaft 
6 sucks oil 15 into the crankshaft 6, and the oil 15 is also dispersed in 
the upper shell 2, especially on the piston 8 and cylinder 9. 
In the prior art, however, when a compressor, such as a variable speed 
compressor, is driven in low speed, it is impossible to provide sufficient 
lubricating oil to the lubricating part because the rotating force of the 
crankshaft decreases at low speed. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a closed-type 
transmission compressor which is capable of providing the lubricating oil 
to the lubricating part at low operating speeds. 
In order to achieve the above-mentioned object, a closed-type transmission 
compressor according to a first embodiment of the present invention 
comprises an upper shell having a compressing unit and a lower shell 
having a transmission unit, in which the transmission unit includes a 
stator attached to a frame by bolts and generating magnetic power, a rotor 
rotating by the magnetic power of the stator, and a crankshaft rotating by 
rotation of the rotor. The compressing unit includes a slider changing 
rotatory movement of the crankshaft into linear movement, a piston 
attached to the slider and reciprocating in a cylinder, a head cover 
covering the cylinder, an inlet valve between a head and the head cover 
which permits intake of a refrigerant gas, an outlet valve between the 
head and the head cover which permits exhaust of the refrigerant gas, a 
propeller providing an oil in the lower shell to the crankshaft, and a 
screw-shaped oil path groove formed in the inside of crankshaft in which 
the oil flows along the screw-shaped oil path groove. 
Further, a closed-type transmission compressor according to a second 
embodiment of the present invention comprises an oil pump provided on an 
upper side of the crankshaft, an oil inlet pipe for supplying oil from the 
oil pump, and an oil outlet pipe which disperses the oil sucked through 
the oil inlet pipe to the piston or bearing parts requiring oil.

DETAILED DESCRIPTION OF THE INVENTION 
Preferred embodiments of the present invention are described in detail 
hereinafter with reference to the accompanying drawings. 
Referring to FIG. 2, a closed-type transmission compressor according to a 
first embodiment of the present invention comprises an upper shell 101 
having a compressing unit and a lower shell 102 having a transmission 
unit. Lower shell 102 includes a stator 4 attached to a frame using bolts 
and providing magnetic power, a rotor 105 rotating in accordance with the 
magnetic power of the stator 104 and a crankshaft 106 rotating by rotation 
of the rotor 5. The compressing unit includes a slider 107 changing 
rotatory movement of the crankshaft 106 into linear movement, a piston 108 
attached to the slider 109 and reciprocating in a cylinder 109, a head 
cover 113 covering the cylinder 109, an inlet valve 111 between a head 110 
and the head cover 113 which permits intake of a refrigerant gas, an 
outlet valve 112 between the head 110 and the head cover 113 which permits 
exhaust of the refrigerant gas, a propeller 114 conveying oil 115 in the 
lower shell 102 into the crankshaft 106, and a screw-shaped oil path 
groove 116 formed inside of the crankshaft 106 in which the oil 115 flows. 
When electric power is applied to the compressor, the rotor 105 rotates due 
to the induced current between the stator 104 and rotor 105, whereby the 
crankshaft 106 attached to the rotor 105 is rotated. The rotatory movement 
of the crankshaft 106 is changed into linear movement by the slider 107, 
whereby the piston 108 reciprocates in the cylinder 109. 
On the other hand, the propeller 114 provided on a lower side of the 
crankshaft 106 introduces oil 115 into the crankshaft 106. The introduced 
oil is dispersed via the screw-shaped oil path groove 116 into the upper 
shell 102, especially over the piston 108 and cylinder 109. 
As shown in FIGS. 3a-b, a closed-type transmission compressor according to 
a second embodiment of the present invention comprises the upper shell 101 
having the compressing unit and the lower shell 102 having the 
transmission unit which includes the stator 104 attached to the frame by 
bolts. The stator 104 introduces magnetic power, the rotor 105 rotates by 
the magnetic power of the stator 104, and the crankshaft 106 rotations by 
rotation of the rotor 105. The compression device part includes the slider 
107 changing the rotatory movement of the crankshaft 106 into linear 
movement, the piston 108 attached to the slider 109 and reciprocating in 
the cylinder 109, the head cover 113 covering the cylinder 109, the inlet 
valve 111 between the head 110 and the head cover 113 permitting intake of 
the refrigerant gas, the outlet valve 112 between the head 110 and the 
head cover 113 permitting exhaust of the refrigerant gas. A propeller 114 
conveys oil 115 in the lower shell 102 into the crankshaft 106. An oil 
pump piston 223 and cylinder 224 are connected with an eccentric upper 
side part of the crankshaft 106. An oil inlet valve 225, valve sheet 226, 
and an oil inlet head cover 227 are provided on the oil pump cylinder 224. 
An oil inlet pipe 228 connects the oil 115 with the oil inlet head cover 
227, and an oil outlet pipe 229 which disperses the oil sucked through the 
oil inlet pipe 228 to the piston 108 and/or bearing part 235. 
FIG. 4 is a partially enlarged sectional view of the oil pump used in the 
second embodiment of the present invention. When the eccentric part 106a 
of the crankshaft 106 is rotated, the oil pump piston 223 moves to a 
bottom dead point, at this time a spring 221 helps bias the oil pump 
piston 223 to move to the bottom dead point, whereby the oil inlet valve 
225 is opened. The oil 115 in the lower shell 102 then flows via oil inlet 
pipe 228 into the oil pump cylinder 224 because of a pressure difference. 
In accordance with movement of the eccentric part 106a, the oil pump 
piston subsequently moves to a top dead point, at which point flowed oil 
in oil pump cylinder 224 is dispersed over the piston (in case of FIG. 3a) 
or bearing part (in case of FIG. 3b) through the outlet pipe 229 (because 
oil inlet valve 225 is then forced closed). 
In the present invention, it is therefore possible to provide enough 
lubricating oil to a lubricating part of the compressor during low speed 
operation, by providing a screw-shaped oil path groove within the 
crankshaft or providing an oil pump which is driven by an eccentric part 
of the crankshaft. 
It should also be understood that the foregoing relates to only a preferred 
embodiment of the invention, and that it is intended to cover all changes 
and modifications of the example of the invention herein chosen for the 
purposes of the disclosure, which do not constitute from the spirit and 
scope of the invention.