US 6,550,262 B2 · Expansion valve unit

Abstract

An expansion valve unit which prevents a temperature-sensing error from occurring due to transmission of a temperature lowered by the expansion of the refrigerant to a temperature-sensing chamber. An expansion valve unit is configured such that a high-pressure refrigerant guide groove is formed circumferentially in a body between a temperature-sensing chamber and a low-pressure refrigerant passage so as to guide a high-temperature and high-pressure refrigerant from the high-pressure refrigerant guide groove to a valve hole by way of a high-pressure refrigerant passage. By providing the high-pressure refrigerant guide groove, a heat conduction area for conducting heat from the temperature-sensing chamber to the low-pressure refrigerant passage is reduced, and the high-pressure refrigerant guide groove, which is supplied with the high-temperature and high-pressure refrigerant and hence always heated to a high temperature, thermally insulates the temperature-sensing chamber from the low-pressure refrigerant passage. This prevents the temperature-sensing chamber from being adversely affected by the low temperature of the low-pressure refrigerant passage, thereby preventing occurrence of a temperature-sensing error.

Claims15

Dependent claims

An expansion valve unit including

a temperature-sensing chamber for sensing a temperature of a refrigerant at an outlet of an evaporator to have a pressure therein increased and decreased, a high-pressure refrigerant passage formed in a side portion of a body, a low-pressure refrigerant passage formed in an end portion of the body on an opposite side of the temperature-sensing chamber, a valve seat located at an end surface on a low-pressure refrigerant passage side of a valve hole that communicates between the high-pressure refrigerant passage and the low-pressure refrigerant passage, a valve element capable of moving to and away from the valve seat, a spring for urging the valve element in a valve-closing direction, and a shaft for transmitting displacement of the temperature-sensing chamber caused by the increased and decreased pressure therein to the valve element,
the expansion valve unit being characterized by a high-pressure refrigerant guide groove which is formed circumferentially in the body between the temperature-sensing chamber and the low-pressure refrigerant passage such that the high-pressure refrigerant guide groove communicates with the high-pressure refrigerant passage, whereby the temperature-sensing chamber is thermally insulated from the low-pressure refrigerant passage.

Dependencies are inferred from the claim text.

Expansion valve unit

Life of this patent

Expansion valve unit

Life of this patent

Abstract

Claims15