초록 ▼

An expansion valve wherein a plunger slidably fitted in a hollow member for sliding movement and opening and closing valve ports formed in the hollow member is driven by an electromagnetic force, and two chambers defined between opposite ends of the plunger and the hollow member are maintained in co

An expansion valve wherein a plunger slidably fitted in a hollow member for sliding movement and opening and closing valve ports formed in the hollow member is driven by an electromagnetic force, and two chambers defined between opposite ends of the plunger and the hollow member are maintained in communication with each other through a pressure equalization passageway formed in the plunger. The expansion valve is capable of allowing a refrigerant to flow therethrough without any resistance offered to its flow and having ability to allow reversible flow of the refrigerant to take place with high responsiveness.

대표청구항 ▼

1. An expansion valve for controlling the flow of a refrigerant in the refrigeration cycle of a heat pump air conditioner unit including indoor and outdoor heat exchangers and a four-way valve for changing the direction of flow of a refrigerant in said air conditioner according to space heating, spa

1. An expansion valve for controlling the flow of a refrigerant in the refrigeration cycle of a heat pump air conditioner unit including indoor and outdoor heat exchangers and a four-way valve for changing the direction of flow of a refrigerant in said air conditioner according to space heating, space cooling and dry operation modes, said expansion valve comprising: a hollow shaft having a first opening connected to said indoor heat exchanger; a hollow member having a second opening connected to said outdoor heat exhanger and valve port means communicating said first and second openings with each other, a plunger in sliding engagement in a hollow portion of said hollow member for sliding movement to open and close said valve port means, said plunger being formed of magnetic material at least in part, and said valve port means of said hollow member having an opening extending in a direction of the sliding movement of said plunger, the diameter of the second opening of said hollow member being greater than the length of said valve port means opening in the sliding direction; and drive means for said plunger; wherein said plunger drive means comprises an electromagnetic coil secured to the outer side of said hollow member, and a circuit for passing an electric current to said electromagnetic coil, said circuit comprising means for supplying pulse signals of high frequency to said electromagnetic coil, said pulse signals being supplied according to different patterns respectively predetermined for space heating, space cooling and dry operation modes, wherein said plunger drive means comprises a permanet magnet in addition to said electromagnetic coil, wherein said valve port means opening is constituted by a single slot extending in the direction of movement of said plunger, wherein said plunger comprises a pressure equalization passageway maintaining two chambers defined between opposite ends of said plunger and said hollow portion of said hollow member in communication with each other, and further comprising an attracting member secured to said hollow portion of said hollow member at an end thereof opposite the end at which said second opening is located whereby the position of said plunger can be controlled by controlling the electric current passed to said electromagnetic coil according to space cooling, space heating and dry operation modes irrespective of whether a refrigerant is introduced into the expansion valve through one or the other of said first and second openings. 2. An expansion valve as claimed in claim 1, wherein said hollow shaft and said hollow member are both in the form of pipes, and said hollow shaft is secured to one end thereof to said hollow member in a manner to cover said valve port means. 3. An expansion valve as claimed in claim 1, wherein said valve port means comprise at least one orifice opened and closed by said plunger when it moves in a range of small strokes, and at least one communication aperture opened and closed by said plunger when it moves in a range of large strokes, said communication aperture having a larger cross-sectional area than said orifice. 4. An expansion valve as claimed in claim 1, wherein said plunger is constructed at an end face thereof in a manner to directly open and close said valve port means. 5. In an air conditioner unit comprising indoor and outdoor heat exchangers and a four-way valve for changing the direction of flow of a refrigerant in said air conditioner unit according to space heating, space cooling and dry operation modes of said air conditioner unit, the improvement comprising an expansion valve for controlling the flow of the refrigerant in the air conditioner unit, said expansion valve comprising a hollow shaft having a first opening connected to said indoor heat exchanger, a hollow member having a second opening connected to said outdoor heat exchanger and having valve port means communicating said first and second openings with each other, a plunger in sliding engagement in a hollow portion of said hollow member for sliding movement to open and close said valve port means, said plunger being formed of magnetic material at least in part, the valve port means of said hollow member being large enough to allow the refrigerant to flow therethrough without any resistance being offered to its flow when said valve port means is fully opened by said plunger movement, drive means for said plunger, said plunger drive means comprising an electromagnetic coil secured to the outer side of said hollow member, and a circuit for passing an electric current to said electromagnetic coil, said circuit comprising means for supplying pulse signals of high frequency to said electromagnetic coil, said pulse signals being supplied according to different patterns respectively predetermined for space heating, space cooling and dry operation modes, wherein said plunger drive means comprises a permanent magnet in addition to said electromagnetic coil, wheren said plunger comprises a pressure equalization passageway maintaining two chambers defined between opposite ends of said plunger and said hollow portion of said hollow member in communication with each other, and further comprising an attracting member secured to said hollow portion of said hollow member at an end thereof opposite the end at which said second opening is located whereby the position of said plunger can be controlled by controlling the electric current passed to said electromagnetic coil according to space cooling, space heating and dry operation modes irrespective of whether a refrigerant is introduced into the expansion valve through one or the other of said first and second openings.