Scroll compressor

Abstract

A scroll compressor comprises a fixed scroll, an orbiting scroll engaged with the fixed scroll to form a compression chamber therebetween, a back pressure chamber arranged at a back side of an end plate of the orbiting scroll, a back pressure hole formed in the end plate of the orbiting scroll to form a fluidal communication between the compression chamber and the back pressure chamber, and a release valve mechanism for discharging the fluid from the compression chamber to the discharge space when a pressure in the compression chamber is higher than the pressure in the discharge space, wherein the back pressure hole and the release flow path are arranged to prevent both of the fluidal communication and the another fluidal communication from being formed simultaneously.

Description

BACKGROUND OF THE INVENTION[0001]The present invention relates to a scroll compressor including a back pressure chamber on a back side of an orbiting scroll or a fixed scroll to press one of the scrolls against the other one of the scrolls with a back pressure.[0002]The scroll compressor has the fixed scroll with a spiral wrap set upright on a base plate and the orbiting scroll with a spiral wrap set upright on an end plate. The scroll compressor compresses a fluid (e.g., a gas coolant in a refrigeration cycle) by arranging the wraps of both of the scrolls to be engaged with each other and opposed to each other, and making the orbiting scroll orbit to reduce volumes of a plurality of compression chambers formed between the wraps.[0003]This compression operation produces a force in an axial direction for separating the fixed scroll and the orbiting scroll from each other. When the scrolls are separated from each other, a gap is produced between tooth tip and bottom of the respective ...

AI Technical Summary

Benefits of technology

[0009]An object of the present invention is to decrease an influence of a pressure variation in the back pressure chamber caused by the release mechanism in the scroll compressor including the back pressure chamber at the back side of the end plate of the scroll and the release mechanism.

[0010]In order to solve the above mentioned problems, a scroll compressor according to the invention, comprises a fixed scroll including a base plate and a spiral wrap projecting from the base plate, an orbiting scroll including an end plate and another spiral wrap projecting from the end plate and engaged with the fixed scroll to form a compression chamber therebetween, a discharge space for receiving a compressed fluid from the compression chamber, a back pressure chamber arranged at a back side of at least one of the fixed scroll and the orbiting scroll to press the fixed scroll and the orbiting scroll against each other, a back pressure hole formed in at least one of the base plate and the end plate to enable a fluidal communication to be formed between the compression chamber and the back pressure chamber so that a pressure in the back pressure chamber is kept between an intake pressure and a pressure in the discharge space, and a release valve mechanism including a release flow path to enable another fluidal communication to be formed between the compression chamber and the discharge space, and a valve arranged between the release flow path and the discharge space to open the release flow path to enable the fluid to be discharged from the compression chamber to the discharge space when a pressure in the compression chamber is higher than the pressure in the discharge space, so that an excessive compression in the compression chamber is prevented, wherein the back pressure hole and the release flow path are arranged to prevent both of the fluidal communication and the another fluidal communication from being formed simultaneously during each orbital revolution.

[0011]According to another aspect of the invention, a scroll compressor comprises a fixed scroll, an orbiting scroll engaged with the fixed scroll to form a compression chamber therebetween and capable of orbiting, a discharge space for receiving a compressed fluid from the compression chamber, a back pressure chamber arranged at a back side of an end plate of the orbiting scroll to press the orbiting scroll against the fixed scroll, a back pressure hole formed in the end plate of the orbiting scroll to enable a fluidal communication to be formed between the compression chamber and the back pressure chamber, and a release valve mechanism including a release flow path in a base plate of the fixed scroll to enable another fluidal communication to be formed between the compression chamber and the discharge space, and a valve arranged between the release flow path and the discharge space to open the release flow path to enable the fluid to be discharged from the compression chamber to the discharge space when a pressure in the compression chamber is higher than the pressure in the discharge space, so that an excessive compression in the compression chamber is prevented, wherein the back pressure hole and the release flow path are arranged to prevent both of the fluidal communication and the another fluidal communication from being formed simultaneously during each orbital revolution.

[0016]According to the invention, since the back pressure hole and the release flow path are arranged to prevent both of the fluidal communication and the another fluidal communication from being formed simultaneously during an orbital motion of the orbiting scroll, the pressure variation in the back pressure chamber caused by a fluidal leakage from the release valve mechanism is decreased to keep the pressure in the back pressure chamber stably at an optimum degree, so that high performance and reliability of the scroll compressor are obtained.

Problems solved by technology

That is, while the release valve is not in operation, leakage from the discharge space to the compression chamber occurs in the gap between the valve seat and the valve body, and this leakage causes the pressure of the compression chamber to rise.

This also increases a pressure variation of the back pressure chamber and when the leakage from the release valve is extremely large, the pressure of the back pressure chamber becomes excessively large, leading to an increase of sliding loss and deterioration of reliability due to seizing of the end plate.

Furthermore, when the release valve is in operation, that is, under a condition that the pressure of the compression chamber becomes excessive compression, the pressure of the compression chamber increases by the pressure loss corresponding to the channel resistance at the release valve, and therefore if the back pressure hole communicates with the compression chamber, the pressure of the back pressure chamber increases.

Therefore, the pressure of the back pressure chamber also becomes excessively large even when the pressure loss is large, resulting in a problem of causing an increase of sliding loss and deterioration of reliability due to seizing of the end plate.

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