JPH04284190A - Sealed type reciprocating compressor - Google Patents

Abstract

PURPOSE:To suppress the vibration and noise of a sealed type reciprocating compressor used for a refrigerator, etc., improve efficiency, reduce the weight of a piston and maintain airtightness. CONSTITUTION:A sealed type reciprocating compressor is equipped with a piston installed on a piston body 11 which is integrally formed with a cylindrical steel pipe 10 made of aluminium die casting.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetic reciprocating compressor used in electric refrigerators, refrigerator showcases, etc.

0002

BACKGROUND OF THE INVENTION In recent years, there has been a strong tendency to require low noise and low vibration in refrigeration systems for refrigerators, showcases, etc., and many improvements have been made to hermetic reciprocating compressors, which are one of the sources of such noise. For hermetic reciprocating compressors that have a piston, the kinetic energy of the reciprocating motion becomes a source of vibration, so in order to reduce the kinetic energy, it is possible to reduce the weight of the piston. )
Since then, aluminum materials have been used.

[0003] It is also a generally known technique to use piston rings to improve the sealing performance of the sliding surface of the piston.

A piston structure using a conventional piston ring can be found in Japanese Utility Model Application Publication No. 48-69112. A conventional piston structure using piston rings will be described below.

[0005] This will be explained below using FIG. FIG. 3 is a longitudinal sectional view showing only the main parts of a conventional hermetic reciprocating compressor.

1 is a cylinder, 2 is a piston, and an upper piston ring 3 and a lower piston ring 4 are attached to the sliding surface of the cylinder 1. Further, a connecting rod 5 that transmits power from the crankshaft 6 is attached to the piston 2.

The operation will be explained below. First, normally the crankshaft 6 is eccentric, and this eccentric movement is caused to reciprocate by the connecting rod 5 into the piston 2 and moves within the sill 1. As the piston 2 reciprocates, the volume inside the shilling changes and functions as a compressor. The inner wall of the cylinder 1 and the sliding surface of the piston 2 have a compression function and therefore have airtightness. Piston rings 3 and 4 are installed to enhance its functionality.

[0008]

However, in the above conventional structure, the airtightness between the cylinder 1 and the piston 2 is maintained only by the above and lower piston rings 3 and 4.
The contact area of the seal is small, and the piston 2
Because of the structure in which the piston rings 3 and 4 are fitted, it is not possible to achieve a completely airtight state, and as a result, the efficiency of the compressor is reduced.

Further, the piston ring 3, 4 is not provided, and the piston sliding surface directly and entirely contacts the inner wall of the cylinder. A typical piston structure is more airtight than one with a piston ring.

[0010] However, the entire piston is made of iron (casting,
Forging, etc.), the weight of the piston is large and the reciprocating energy is large, which not only becomes a source of vibration but also increases mechanical energy loss. For this reason, the entire piston is made of aluminum or aluminum alloy in an attempt to reduce its weight, but aluminum generally has low hardness, and due to problems such as long-term reliability of sliding parts, it was necessary to use piston rings.

[0011] In other words, there was a drawback in that it was not possible to simultaneously reduce the weight by using aluminum and prevent a decrease in efficiency by using piston rings.

The present invention solves the above-mentioned conventional problems, and provides a hermetic reciprocating compressor that reduces the weight of the piston, maintains airtightness with the cylinder, and has low vibration, low noise, and high efficiency. With the goal.

[0013]

[Means for Solving the Problems] In order to solve the above problems, the structure of the piston of the hermetic reciprocating compressor of the present invention includes a cylindrical steel pipe at the side circumference and an integral structure formed by aluminum die-casting on this steel pipe. This is what I did.

[0014] Furthermore, an aluminum piston with a female thread cut inside the cylindrical steel pipe and a male thread cut on the outside surface is screwed into the piston.

[0015]

[Operation] With this structure, the weight of the piston can be reduced, and the airtightness between the piston and the cylinder can be maintained.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are longitudinal cross-sectional views of the piston structure of a hermetic reciprocating compressor. In FIG. 1, 10 is a cylindrical steel pipe, and a piston 11 is formed by die-casting aluminum into this steel pipe 10. After die-casting, the outer circumferential side of the steel pipe 10 and the piston body 11 are subjected to necessary machining (cutting, polishing, etc.) and sealed. Incorporate into type reciprocating compressor.

In FIG. 2, reference numeral 15 is a cylindrical steel pipe with a female thread cut on its inner surface, and a piston body 16.
A male thread is cut on the outer surface of the piston body 16, and a cylindrical steel pipe 15 is screwed into the piston body 16. The outer circumferential side of the steel pipe 15 and the piston body 16 are subjected to other necessary machining (cutting, polishing, etc.), and then assembled into a hermetic reciprocating compressor.

According to the well-constructed piston structure described above, the piston can be made lightweight by using aluminum or aluminum alloy as the material for the piston bodies 11 and 16, and the steel pipe 10 or 15 can be attached to it. By doing so, a sufficient contact area between the steel pipe and the cylinder can be provided, and airtightness can be maintained. Further, the steel pipe 10 or 11 is in close contact with the piston body 11 or 16 by die-casting or screwing, so that airtightness can be sufficiently ensured. Furthermore, the sliding surface of the piston is made of a steel tube, and its reliability in terms of wear and other issues is equivalent to that of a steel piston.

[0020]

Effects of the Invention As described above, the present invention provides a piston that is die-cast aluminum into a cylindrical steel pipe, or a piston that is threaded into a cylindrical steel pipe and threaded into a similarly threaded piston made of aluminum or aluminum alloy. By doing so, it is possible to reduce the weight of the piston, maintain airtightness with the cylinder, and ensure long-term reliability. Reducing the weight of the piston reduces vibration and noise, as well as reduces mechanical losses. Therefore, according to the present invention, a hermetic reciprocating compressor with high efficiency, low noise, and high reliability can be manufactured.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a piston according to an embodiment of the present invention.

[Figure 2
] Longitudinal sectional view of a piston according to another embodiment of the present invention

[Figure 3] Longitudinal cross-sectional view of a piston using a conventional piston ring

[Explanation of symbols]

10 Steel pipe 11 Piston body 15 Steel pipe 16 Piston body

Claims (2)

[Claims] 1. A hermetic reciprocating compressor comprising a cylindrical steel pipe and a piston die-cast from aluminum on the steel pipe. 2. A hermetic reciprocating compressor having an internally threaded cylindrical steel tube and an aluminum piston with a threaded outer surface into which the steel tube is screwed.