JPS62147057A - Enclosed type reciprocating compressor - Google Patents

Abstract

PURPOSE:To reduce top clearance volume and improve the suction efficiency of a compressor by closing the delivery hole of a valve plate at the upper dead center of a piston. CONSTITUTION:The delivery hole 22a of a valve plate is so tapered as to have a smaller bore toward a cylinder head 23. On the contrary, a convex 21 similar to the internal shape of the delivery hole 22a is formed on the head of a piston 20. And the convex 21 is so made as to close the delivery hole 22a at the upper dead center of the piston 20.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a hermetic reciprocating compressor used in refrigeration equipment such as refrigerators and showcases.

Conventional Technology In recent years, hermetic reciprocating compressors (hereinafter referred to as compressors) have become much more efficient due to the need for energy conservation. However, requests for further improvements in energy efficiency are mainly coming from overseas users.

An example of a conventional compressor will be described below with reference to the drawings. In FIG. 4, reference numeral 1 denotes a compressor, and an electric motor element 3 and a compression mechanism 4 are housed inside a sealed case 2. The compression mechanism 4 includes a piston 6 that reciprocates within the cylinder 5.
, a valve plate 7 equipped with a pulp mechanism, and other parts. FIG. 5 is a sectional view of the main part of FIG. 4, and a valve plate 7 is attached to the cylinder 6 with a gasket 8 and a suction pulp lead 9 in between. A valve mechanism 10 (only a portion of which is shown) is fixed to the valve plate 7 . A discharge pulp lead 10a, which is a part of the valve mechanism, closes the discharge holes 7a and 7b of the valve plate 7. 6 is a piston.

The operation of the compressor configured as above will be explained below.

In FIG. 5, when the piston 6 moves toward the top dead center in the cylinder S, the refrigerant gas is compressed, pushing up the discharge valve lead 10a, and the piston 6 discharged from the discharge holes 7a and 7b moves toward the top dead center. At some point, the gas accumulated in the gap between the inside of the discharge hole 7'ci;'7'b and the space between the top dead center of the piston (hereinafter referred to as the top clearance volume) 11 is not exhausted, and the piston descends from the top dead center. It re-expands during the suction process, reducing the suction efficiency of the compressor.

In an effort to reduce the top clearance volume 11 in order to improve the efficiency of the energy-saving compressor described above, the thickness of the gasket is carefully selected and used. On the other hand, attempts have been made to make the diameter of the discharge hole thinner in order to reduce the volume inside the discharge holes 7a and rb, but if the diameter is made too thin, it becomes difficult for gas to be discharged during the discharge process, causing an overcompression phenomenon, and on the contrary, the efficiency of the compressor decreases. Due to the balance between the two,
The volume of the discharge hole cannot be reduced compared to conventional methods.

Problems to be Solved by the Invention However, with the above configuration, the volume inside the discharge hole cannot be reduced due to the above-mentioned reasons. The suction efficiency of the compressor deteriorates, and unless the dog clearance volume 11 is reduced, it is difficult to create a compressor that is more energy efficient than the conventional compressor.

The present invention has been made in view of the above problems, and is intended to improve the suction efficiency of the compressor and provide a compressor with good energy efficiency.

Means for Solving the Problems In order to solve the above problems, the compressor of the present invention includes a valve plate provided with a tapered discharge hole whose hole diameter is smaller on the side of the shaft 2 head, and It is composed of a discharge valve reed provided on one side and a piston having a protrusion on its head so as to close the tapered discharge hole of the valve plate at the top dead center.

According to the above-described structure, the present invention provides a tapered protrusion approximately equal to the volume of the discharge hole of the valve plate on the piston head, and the protrusion enters the discharge hole at the top dead center of the piston. As a result, the top clearance volume is almost eliminated.

Further, in the compression process, since the discharge hole and the protrusion are tapered, the gas flow is smooth and there is no overcompression phenomenon.

EXAMPLE Hereinafter, a compressor according to an example of the present invention will be described with reference to the drawings. FIG. 1 shows a cross section of a main part at the top dead center of a piston in an embodiment of the present invention, and the same parts as those in the conventional FIG. 5 are given the same numbers and their explanations are omitted. A piston 20 has a tapered protrusion 21 on its head, which is knurled 21a on its leg and press-fitted into a hole 20a in the piston head. 22 is a valve plate having a tapered discharge hole 22a. A cylinder head 23 covers the valve mechanism 10 and is hermetically fixed to the valve plate 22. As shown in the figure, there is almost no top clearance poly team 11.

FIG. 2 shows the piston in FIG. 1 before the top dead center, and the gas flows well from the sufficient gap between the tapered discharge hole 22a and the protrusion 21, and the gas flows as shown by the arrow. ,
There is no overcompression phenomenon. FIG. 3 shows a view from the ■-■ arrow in FIG.
It is placed offset from the center of o.

As described above, according to this embodiment, a tapered discharge hole 22a is formed in the valve plate 22, a protrusion 21 is provided on the piston/head, and the discharge hole 22a is provided at the top dead center of the piston 2o. By inserting the protrusion 21 into the top clearance, the top clearance volume is almost eliminated, and in the discharge process, the gas is discharged with a good flow from a sufficient gap, so there is no re-expansion or overcompression phenomenon, and compression with good energy efficiency is achieved. It becomes an opportunity.

Effects of the Invention As described above, the present invention provides a valve plate having a tapered discharge hole with a small hole diameter on the cylinder head side;
By constructing the valve plate with a piston having a protrusion on its head so as to close the tapered discharge hole of the valve plate at the top dead center, the following effects can be obtained.

(1) There is almost no top clearance volume,
Since there is almost no re-expansion, the suction efficiency of the compressor is improved and performance is improved.

(2) In the discharge process, the gas is discharged in a good flow through sufficient gaps, so there is no overcompression phenomenon and a compressor with good energy efficiency can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a hermetic reciprocating compressor according to an embodiment of the present invention, FIG. 2 is a sectional view of the piston in FIG. 1 before top dead center, and FIG. 3 is a sectional view of the piston in FIG. -10a...
Discharge pulp lead, 22... Valve play),
22a...Tapered discharge hole, 2°...
... Piston, 21 ... Convexity, 23 ...
·cylinder head. Name of agent: Patent attorney Toshio Nakao and 1 other person/θ
U...-Loj stop Ωb bleed 2θ---Piston 2I・-Protrusion Fig. 2 Fig. 3 Fig. 4

Claims (1)

[Claims] a valve plate provided with a tapered discharge hole having a smaller diameter on the cylinder head side; a discharge valve lead provided on one side of the discharge hole of the valve plate;
A hermetic reciprocating compressor, comprising: a piston having a protrusion on its head so as to close the tapered discharge hole of the valve plate at top dead center.