JPH03271570A - Closed type electric motor-driven compressor - Google Patents

Abstract

PURPOSE:To reduce heating of refrigerant gas, guided to a suction chamber, so as to improve volumetric efficiency by mounting a heating insulating cap of PBT or the like with small heat conductivity so as to provide a heat insulating layer in a space from an internal wall of the suction chamber. CONSTITUTION:Refrigerant gas of low pressure and low temperature, returned from a refrigerant cycle (not shown in the drawing), is guided to a cylinder 10 through a suction muffler 18. Here a heat insulating cap 20, consisting of PBT or the like with small heat conductivity, is mounted so as to provide a heat insulating layer 21 between itself and an internal wall of a suction chamber 7. Heating of the suction refrigerant gas, inflowing into the suction chamber 7 from a cylinder head 6 heated to a high temperature, is reduced by the heat insulating cap 20 and refrigerant gas with which the heat insulating layer 21 is filled.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a hermetic electric compressor used in refrigerators, near conditioners, and the like.

BACKGROUND ART In recent years, hermetic electric compressors (hereinafter referred to as compressors) are required to have high efficiency and low noise.

An example of a conventional compressor will be described below with reference to the drawing. FIGS. 3 and 4 show a compressor shown in Japanese Patent Application Laid-Open No. 1-37596.

1 is an airtight container, 2 is a compression element elastically supported within the airtight container 1, and 3 is an electric element disposed above the compression element. 4 is a stator, and 5 is a rotor, which constitute the electric element 3. 6 is a cylinder head forming a suction chamber 7 and a discharge chamber 8; 9 is a cylinder block having a cylinder 10; 11 is a pulp plate having a suction hole 12 and a discharge hole 13; 14 is a piston; 15 is a crankshaft; 16
1 is a connecting rod connected to the eccentric portion 17 of the crankshaft;
8 is a suction muffler having a communication pipe, and constitutes the compression element 2.

In the above configuration, the low-temperature, low-pressure refrigerant gas returning from the refrigeration sign Iv (not shown) passes through the suction pipe (not shown), the suction muffler 18 9, and the cylinder 1.
It leads to 0. The refrigerant gas compressed by the compression element 3 to a high temperature and high pressure is discharged through a discharge line (not shown) and a discharge pipe (
(not shown) through t and is guided to a frozen sign μ (not shown).

Problems to be Solved by the Invention However, in the above configuration, when the compressor is in operation, the cylinder head 6 is heated by the heat generated by the compression element 2 and the electric element 3, resulting in a high temperature. The high-temperature, high-pressure refrigerant gas compressed within the cylinder 10 is led to the discharge chamber 8 formed in the cylinder head 6, so the temperature near the discharge chamber 8 becomes extremely high. Therefore, when the suction refrigerant gas is led to the suction chamber 7, it is heated particularly from the discharge chamber 8gIII. For this reason, the specific volume of the refrigerant gas increases and flows into the cylinder 10, resulting in a problem of lowering the volumetric efficiency of the pressure i machine.

In view of the above-mentioned problems, the present invention has been developed to increase the amount of refrigerant gas in the suction chamber! The present invention provides a pressure machine with reduced t-reduction and high volumetric efficiency.

Means for Solving the Problems In order to solve the above-mentioned problems, the hermetic electric compressor of the present invention uses polybutylene terephthalate having low thermal conductivity so as to have a gap with the inner wall of the suction chamber. It is equipped with a structure in which a heat insulating cap is attached.

Effects of the present invention With the above-described configuration, when refrigerant gas is guided to the suction chamber, it is guided to the suction chamber without coming into contact with the cylinder head, thereby preventing heat from the refrigerant and using the gap as a heat insulating space. Heat from the cylinder head is difficult to transfer through the heat insulating cap housing.

EXAMPLE Hereinafter, a compressor according to an example of the present invention will be described with reference to the drawings. Note that parts that are the same as those in the conventional example will be described using the same reference numerals, and parts that are the same in structure and operation will be omitted.

19' is a communication pipe made of polybutylene terephthalate (hereinafter referred to as PBT) with low thermal conductivity, which is included in the suction muffler 18, and 20 is a heat conduction pipe installed with a gap between it and the inner wall of the suction chamber 7. The cap is made of a heat insulating cap made of PBT or the like with a low ratio and has a rib 20a on the outer periphery and a hole 20b into which the communication pipe 19' is inserted. 21 is a heat insulating layer between the inner wall of the suction chamber 7 and the heat insulating cap 2o.

With the above-described configuration, the low-temperature, low-pressure refrigerant gas returned from the refrigeration sign lv (not shown) passes through the suction pipe (not shown), the suction muffler 18, and enters the cylinder 1.
lead to o. The refrigerant gas compressed by the compression element 3Vc to a high temperature and high pressure is guided to a refrigeration cycle (not shown) through a discharge fin (not shown) and a discharge pipe (not shown).

In a compressor having such a structure, the heat insulating cap 20 made of PBT or the like having low thermal conductivity is installed so as to have the above-mentioned cross section P and layer 21 between it and the inner wall of the suction chamber 7. , the heat insulating cap 20 and the l! It can be reduced by the refrigerant gas filling the 7r heat layer 21. Since the housing and the communication pipe 19' are also made of a material such as PBT which has a low thermal conductivity, heating of the suction refrigerant gas can be reduced even when passing through the communication pipe 19'.

Therefore, it is possible to reduce the increase in the specific volume of the refrigerant gas flowing into the cylinder 10, and it is possible to improve the volumetric efficiency of the compressor.

Effects of the Invention As described above, the present invention provides a heat insulating cap made of PBT or the like having a low thermal conductivity so as to have a heat insulating layer between it and the inner wall of the suction chamber. Since the heating of the refrigerant gas can be reduced, the increase in the specific volume of the suction refrigerant gas can be reduced, and the volumetric efficiency of the hermetic electric compressor can be improved.

[Brief explanation of drawings]

Fig. 1 is a sectional view of essential parts of a hermetic electric compressor according to an embodiment of the present invention, Fig. 2 is a tactile view taken along the line ■-■ in Fig. 1, and Fig. 3 is a sectional view of a conventional hermetic electric compressor. 4 is a sectional view of a main part of FIG. 3. 1... Airtight container, 2... Correction element, 3
......Electric element, 6...Cylinder head, 7...Suction chamber, 8...Discharge chamber, 9...
...Cylinder block, 10...Cylinder, 11...Valve plate, 12...
・Suction hole, 13...Discharge hole, 14...
pian), 18...pa suction muffler, 19'-...
...Communication pipe, 2o...Insulation cap, 20a
...Rib, 20b...Insertion hole, 21.
...Insulation layer.

Claims (3)

[Claims] (1) A compression element whose constituent elements include a cylinder block having an electric element and a cylinder elastically supported in a closed container, a cylinder head attached to the cylinder block and forming a suction chamber and a discharge chamber, and a piston. a valve plate having a suction hole and a discharge hole interposed between an end surface of the cylinder on which the cylinder slides and the cylinder head; and a suction muffler having a communication pipe whose one end communicates with the suction chamber. . A hermetic electric compressor, characterized in that a polybutylene terephthalate heat insulating cap with low thermal conductivity is attached so as to have a gap between it and the inner wall of the suction chamber. (2) The hermetic electric compressor according to claim 1, wherein the communicating pipe is made of polybutylene terephthalate having low thermal conductivity. (3) The hermetic electric compressor according to claim 1, wherein the heat insulating cap is container-shaped and has a rib on its outer periphery that contacts the wall surface of the suction chamber, and has a hole into which the communication pipe is inserted.