Magnetically latched reversing valve

Abstract

A magnetically latched reversing valve for a heat pump is provided. The reversing valve imparts an axial force on a flux ring, the flux ring being integrated into a sliding valve spool as a magnetically latched, two position reversing valve. In particular, the flux ring moves axially in response to an electromagnetic field generated by a solenoid coil, while an array of permanent magnets provide the latching force to hold the flux ring in position. The flux ring is disk-shaped or ring-shaped, being movable in fixed relation with the valve spool. The reversing valve consumes electrical power only during the switching process, not while maintaining the valve position. This reduced power consumption leads to reduced heat generation, and the reversing valve maintains its position even in the event of a power failure, ensuring its reliability.

1 . A magnetically latched reversing valve, the reversing valve comprising:
 a valve body including an input port for fluid communication with a compressor and a plurality of output ports for fluid communication with first and second heat exchangers;   a valve spool slidably disposed within the valve body for coupling the input port to selective ones of the plurality of output ports;   a flux ring coupled to the valve spool and moveable in fixed relation with the valve spool, the flux ring being formed of a ferromagnetic material; and   a stator assembly comprising:
 an electromagnetic coil wound about a bobbin defining an inner diameter, the coil configured to allow an electrical current to pass therethrough, 
 a plurality of magnets disposed end-to-end adjacent the inner diameter of the bobbin with magnetic fields directed toward the flux ring, the first plurality of magnets being centered symmetrically in relation to the bobbin, 
 wherein the flux ring is movable between a first position and a second position in response to a direction of an electrical current in the electromagnetic coil, and wherein the flux ring is latchable in the first position by the plurality of magnets and is latchable in the second position by the plurality of magnets. 
   
     
     
         2 . The reversing valve of  claim 1 , further including a first ferromagnetic end plate adjacent a first axial surface of the bobbin and a second ferromagnetic end plate adjacent a second axial surface of the bobbin, wherein the first and second ferromagnetic end plates are ring-shaped and provide a flux path for magnetic field lines generated by the electromagnetic coil. 
     
     
         3 . The reversing valve of  claim 2 , wherein the first and second ferromagnetic end plates cooperate to define an annular flange with a plurality of mounting holes therein, the annular flange extending around an outer periphery of the bobbin. 
     
     
         4 . The reversing valve of  claim 1 , wherein the flux ring defines an air gap with respect to the plurality of magnets. 
     
     
         5 . The reversing valve of  claim 1 , wherein the flux ring is formed from a ferromagnetic material and is physically coupled to the valve spool. 
     
     
         6 . The reversing valve of  claim 5 , wherein the flux ring is disk-shaped or ring-shaped. 
     
     
         7 . The reversing valve of  claim 1 , wherein the plurality of magnets include:
 a first plurality of magnets disposed end-to-end adjacent the inner diameter of the bobbin, the first set of magnets being fixed in relation to the bobbin,   a second plurality of magnets disposed end-to-end adjacent the inner diameter of the bobbin, the second set of magnets being fixed in relation to the bobbin,   a ring magnet disposed adjacent the inner diameter of the bobbin between the first plurality of magnets and the second plurality of magnets.   
     
     
         8 . The reversing valve of  claim 7 , wherein the polarity of the first plurality of magnets is opposite of the polarity of the second plurality of magnets. 
     
     
         9 . A stator assembly for a reversing valve having a flux ring coupled to a valve spool, the stator assembly comprising:
 an electromagnetic coil wound about a bobbin defining an inner diameter, the electromagnetic coil configured to allow an electrical current to pass therethrough;   a first plurality of magnets disposed end-to-end adjacent the inner diameter of the bobbin, the first plurality of magnets being fixed in relation to the bobbin;   a second plurality of magnets disposed end-to-end adjacent the inner diameter of the bobbin, the second set of magnets being fixed in relation to the bobbin; and   a ring magnet disposed adjacent the inner diameter of the bobbin between the first plurality of magnets and the second plurality of magnets,   wherein the flux ring is movable between a first position and a second position in response to a direction of an electrical current in the electromagnetic coil, and wherein the flux ring is latchable in the first position by the first plurality of magnets and is latchable in the second position by the second plurality of magnets.   
     
     
         10 . The stator assembly of  claim 9 , further including a first ferromagnetic end plate adjacent a first axial surface of the bobbin and a second ferromagnetic end plate adjacent a second axial surface of the bobbin, wherein the first and second ferromagnetic end plates are ring-shaped and provide a flux path for magnetic flux field lines generated by the electromagnetic coil. 
     
     
         11 . The stator assembly of  claim 10 , wherein the first and second ferromagnetic end plates cooperate to define an annular flange with a plurality of mounting holes therein, the annular flange extending around an outer periphery of the bobbin. 
     
     
         12 . The stator assembly of  claim 9 , wherein the flux ring defines an air gap with respect to the first plurality of magnets and the second plurality of magnets. 
     
     
         13 . The stator assembly of  claim 9 , wherein:
 the first plurality of magnets, the second plurality of magnets, and the ring magnet define a uniform radial width; and   the first and second plurality of magnets each define an axial width that is greater than an axial width defined by the ring magnet.   
     
     
         14 . The stator assembly of  claim 9 , wherein the flux ring is latchable in each of the first and second positions without an electrical current in the electromagnetic coil. 
     
     
         15 . The stator assembly of  claim 9 , wherein the polarity of the first plurality of magnets is opposite of the polarity of the second plurality of magnets. 
     
     
         16 . A heat pump comprising:
 a compressor having an input port and an output port;   an outdoor heat exchanger;   an indoor heat exchanger; and   the reversing valve of  claim 1 .   
     
     
         17 . The heat pump of  claim 16 , wherein, in a space cooling mode, the reversing valve couples the output port of the compressor to the outdoor heat exchanger and couples the input port of the compressor to the indoor heat exchanger. 
     
     
         18 . The heat pump of  claim 16  wherein, in a space heating mode, the reversing valve couples the output port of the compressor to the indoor heat exchanger and couples the input port of the compressor to the outdoor heat exchanger. 
     
     
         19 . A stator assembly for a reversing valve, the stator assembly comprising:
 an electromagnetic coil wound about a bobbin defining an inner diameter, the electromagnetic coil configured to allow an electrical current to pass therethrough;   an isotropic ring magnet adjacent the inner diameter of the bobbin, the isotropic ring magnet being fixed in relation to the bobbin; and   a flux ring coupled to a valve spool and moveable in fixed relation with the valve spool, the flux ring being formed of a ferromagnetic material,   wherein the flux ring is movable between a first position and a second position in response to a direction of an electrical current in the electromagnetic coil, and wherein the flux ring is latchable in the first position by the isotropic ring magnet and is latchable in the second position by the isotropic ring magnet.   
     
     
         20 . The stator assembly of  claim 19 , wherein the isotropic ring magnet is equal in axial width to that of the bobbin and in contact with the inner diameter of the bobbin. 
     
     
         21 . The stator assembly of  claim 19 , wherein the flux ring defines an air gap with respect to the isotropic ring magnet. 
     
     
         22 . The stator assembly of  claim 19 , further including a first ferromagnetic end plate adjacent a first axial surface of the bobbin and a second ferromagnetic end plate adjacent a second axial surface of the bobbin, wherein the first and second ferromagnetic end plates are ring-shaped and provide a flux path for magnetic field lines generated by the electromagnetic coil. 
     
     
         23 . The stator assembly of  claim 19 , wherein the isotropic ring magnet forms a Halbach configuration with a center region having a radially directed field. 
     
     
         24 . The stator assembly of  claim 19 , further including anisotropic magnets to apply an increased axial force on the flux ring. 
     
     
         25 . The stator assembly of  claim 19 , wherein a cross-sectional geometry of the bobbin, the isotropic ring magnet, and the flux ring is cylindrical, triangular, or rectangular.