JPH0599141A - Closed type motor-operated compressor - Google Patents

Abstract

PURPOSE:To reduce suction heating of refrigerant gas and to damp pulsation occurring owing to spitting. CONSTITUTION:By mounting a heat insulating cap 25, such as polybutylene terephthalate, having low thermal conductivity, in such a way that a gap serving as a heat insulating layer 30 is provided between the inner wall of a suction chamber 7 and the cap, heating of refrigerant gas guided to the suction chamber 7 is reduced. Further, a spitting hole 28 is formed in a surface positioned facing the suction hole of the heat insulating cap 25, whereby spittied refrigerant gas is guided to the heat insulating layer 30 to damp pulsation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetic electric compressor used in refrigerators, air conditioners and the like.

[0002]

2. Description of the Related Art In recent years, a hermetic electric compressor (hereinafter referred to as a compressor) is required to have high efficiency and low noise.

An example of a conventional compressor will be described below with reference to the drawings. 3 and 4 are disclosed in JP-A-1-375.
This is the compressor shown in Japanese Patent Publication No. 96.

Reference numeral 1 is a closed container, 2 is a compression element elastically supported in the closed container 1, and 3 is an electric element disposed above the compression element. Reference numeral 4 is a stator, and 5 is a rotor, which constitutes the electric element 3.

6 is a cylinder head having a suction chamber 7 and a discharge chamber 8, 9 is a cylinder block having a cylinder 10, 11 is a valve plate having a suction hole 12 and a discharge hole 13, 14 is a suction lead, and 15 is a Piston, 16 is a crank shaft, 17 is a connecting rod connected to the eccentric part 18 of the crank shaft, 19 is a suction muffler having a communication pipe 20, 2
Reference numeral 1 is a baffle that divides the suction muffler 19 into an expansion chamber 22 and a resonance chamber 23, and 24 is a resonance hole provided in the baffle, which constitutes the compression element 2.

In the above structure, the low-temperature low-pressure refrigerant gas returned from the refrigeration cycle (not shown) is sucked into the suction pipe (not shown), the suction muffler 19, the suction chamber 7, and the suction hole 12. Through the suction lead 14 to the cylinder 10 to be compressed into high temperature and high pressure, and passes through a discharge line (not shown) and a discharge pipe (not shown),
It has a structure that leads to a refrigeration cycle (not shown).

[0007]

However, in the above-mentioned structure, since the suction lead 14 opened at the time of starting the compression is not completely closed at the start of compression, a part of the refrigerant gas sucked into the cylinder 10 is the above-mentioned. It is pushed back (blown back) to the suction hole 12, the suction chamber 7, and the suction muffler 19, which causes pulsation in the suction system. This pulsation is transmitted to the evaporator (not shown) of the refrigeration cycle and vibrates to cause noise.

Further, when the compressor is in operation, the compression element 2
Also, the cylinder head 6 is heated to a high temperature by the heat generated by the electric element 3. Further, since the high temperature and high pressure refrigerant gas compressed in the cylinder 10 is guided to the discharge chamber 8 formed in the cylinder head 6, the temperature near the discharge chamber 8 becomes extremely high.

Therefore, the suction refrigerant gas is transferred to the suction chamber 7
When it is led to, it is heated especially from the discharge chamber 8 side.
Therefore, the specific volume of the refrigerant gas increases, and the cylinder 1
Since it flows into 0, there was a problem of reducing the volumetric efficiency of the compressor.

The present invention solves the conventional problems.
The purpose is to reduce the heating of the refrigerant gas in the suction chamber and increase the volumetric efficiency.

Still another object of the present invention is to provide a compressor that damps pulsation due to blowback and reduces vibration and noise of an evaporator in a refrigeration cycle.

[0012]

In order to achieve this object, the hermetic electric compressor of the present invention has a polybutylene terephone having a small thermal conductivity so as to have a gap as an adiabatic layer between it and the inner wall of the suction chamber. Attach the phthalate heat insulating cap.

Further, the heat insulating cap has a structure in which a small hole to be a blowback hole is provided on a surface of the heat insulating cap facing the suction hole.

[0014]

According to the present invention, the refrigerant gas sucked in is guided to the suction chamber without coming into contact with the cylinder head.
The heating of the refrigerant gas is prevented, and the gap is filled with the refrigerant gas to form a heat insulating layer, which makes it difficult for the heat of the cylinder head to be transferred to the heat insulating cap.

Further, the refrigerant gas blown back is guided to the heat insulating layer through the blowback hole provided in the heat insulating cap.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A compressor according to an embodiment of the present invention will be described below with reference to the drawings. The same parts as those in the conventional example will be described using the same reference numerals, and the same parts in the configuration and operation will be omitted.

1 and 2 are cross-sectional views of the essential parts of the embodiment.
Reference numeral 25 denotes a heat insulating cap made of polybutylene terephthalate (hereinafter referred to as PBT) having a small thermal conductivity, which is installed so as to have a gap between the inner wall of the suction chamber 7 and the rib 26 on the outer periphery and the communication pipe 20 is inserted. A blowback hole 28 is provided on the surface facing the insertion hole 27 and the suction hole 12.

Reference numeral 29 is a rib groove into which the rib 26 provided in the cylinder head 6 is inserted. Reference numeral 30 denotes a heat insulating layer between the inner wall of the suction chamber 7 and the heat insulating cap 25.

In the structure described above, the low-temperature low-pressure refrigerant gas returned from the refrigeration cycle (not shown) is sucked into the suction pipe (not shown), the suction muffler 19, the suction chamber 7, and the suction hole 12. Through the suction lead 14 to the cylinder 10 to be compressed into high temperature and high pressure, and passes through a discharge line (not shown) and a discharge pipe (not shown),
It has a structure that leads to a refrigeration cycle (not shown).

In the compressor having such a structure, the heat insulating cap 25 such as PBT having a small thermal conductivity is used.
Is installed so as to have the heat insulating layer 30 between the suction chamber 7 and the inner wall of the suction chamber 7, and heats the suction refrigerant gas flowing into the suction chamber from the hot cylinder head 6 to the heat insulating cap 25. And it can be reduced by the refrigerant gas filling the heat insulating layer 30.

Therefore, the increase in the specific volume of the refrigerant gas flowing into the cylinder 10 can be suppressed, and the volumetric efficiency of the compressor can be improved.

The refrigerant gas blown back by providing the blowback hole 28 in the heat insulating cap 25 is guided to the heat insulating layer 30. The heat insulating layer 30 functions as a resonance type silencer for the sucked refrigerant gas, and attenuates noise in the suctioned refrigerant gas that could not be completely attenuated in the resonance chamber 23, but also acts as a resonance type silencer for the blown back refrigerant gas. The pulsation of can be dampened.

Therefore, the pulsation is less likely to be transmitted to the evaporator (not shown) of the refrigeration cycle, and the vibration and noise of the evaporator can be reduced.

[0024]

As described above, according to the present invention, a heat insulating cap such as PBT having a small thermal conductivity is attached so that a heat insulating layer is provided between the suction chamber and the inner wall of the suction chamber. Since the heating of the refrigerant gas can be reduced, an increase in the specific volume of the sucked refrigerant gas can be reduced, and the volumetric efficiency of the hermetic electric compressor can be improved.

Further, since the pulsation can be attenuated in the heat insulating chamber by providing the blowback hole in the heat insulating cap, the pulsation is less likely to be transmitted to the evaporator, and the vibration and noise of the evaporator can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part of a hermetic electric compressor according to an embodiment of the present invention.

FIG. 2 is a view taken along the line II-II ′ of FIG.

FIG. 3 is a sectional view of a conventional hermetic electric compressor.

FIG. 4 is a heat insulation diagram of the main part of FIG.

[Explanation of symbols]

 1 Airtight Container 2 Compressive 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 15 Piston 19 Suction Muffler 20 Communication Pipe 25 Insulation Cap 26 Rib 27 Insertion Hole 28 Blowback Hole 29 rib groove 30 heat insulating layer

Claims (3)

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