Expansion valve

Abstract

To provide an expansion valve capable of enhancing manufacturing efficiency of a body and yield from material, thereby reducing manufacturing costs thereof. According to the expansion valve of the present invention, a body is formed by die casting an aluminum alloy, and hence even when the body has a complicated shape, it is possible to easily manufacture the body. Further, even a valve seat, which is difficult to form by extrusion, can be formed integrally with the body, and hence the manufacturing efficiency of the body can be enhanced. Furthermore, component parts, such as the valve seat and the like, conventionally formed by cutting, are also formed integrally with the body by die casting, and hence it is possible to enhance yield from material to reduce manufacturing costs of the expansion valve.

1 . An expansion valve that introduces refrigerant from an upstream side thereof and throttles and expands the refrigerant by passing the refrigerant through a valve section formed therein, to supply the refrigerant to a downstream side thereof, 
 wherein a body including a valve seat as a component part of the valve section is formed by die casting a metal.    
   
   
       2 . The expansion valve according to  claim 1 , wherein the metal is an aluminum alloy.  
   
   
       3 . The expansion valve according to  claim 1 , which is configured as a temperature expansion valve disposed in a refrigeration cycle, for operation such that the temperature expansion valve throttles and expands refrigerant flowing in from a condenser side by passing the refrigerant through the valve section to supply the refrigerant to the evaporator, controls a valve lift of the valve section by sensing a pressure and a temperature of the refrigerant returning from the evaporator, and delivers the refrigerant to a compressor side, 
 wherein the body has a first passage formed therein for introducing the refrigerant from the condenser side and passing the refrigerant through the valve section to deliver the refrigerant to the evaporator, the first passage having the valve section provided in an intermediate portion thereof, and a second passage formed therein for introducing the refrigerant returning from the evaporator and delivering the refrigerant to the compressor side, the first and second passage being formed by die casting an aluminum alloy,    the expansion valve comprising a power element provided on the body on a side of the second passage, opposite from the first passage, for sensing a temperature and a pressure of refrigerant flowing through the second passage, and controlling a valve lift of the valve section provided in the first passage, via a shaft, to thereby control a flow rate of refrigerant delivered to the evaporator.    
   
   
       4 . The expansion valve according to  claim 3 , wherein an adjustment part that supports a valve element as a component part of the valve section, and accommodates an adjustment mechanism that adjusts an urging force for urging the valve element in a valve-closing direction is formed by the die casting, such that the adjustment part communicates with the first passage of the body.  
   
   
       5 . The expansion valve according to  claim 3 , wherein a temperature-sensing part that has the power element connected thereto is formed by the die casting such that the temperature-sensing part communicates with the second passage of the body.  
   
   
       6 . The expansion valve according to  claim 3 , wherein sealing surfaces for arranging sealing members are formed by the die casting on ends of the first passage and the second passage.  
   
   
       7 . The expansion valve according to  claim 1 , wherein a plurality of lightening portions are formed in the body by the die casting.  
   
   
       8 . The expansion valve according to  claim 1 , wherein the body is generally prism-shaped, and wherein lightening portions are formed in side surfaces of the body in respective directions crossing each other by the die casting.  
   
   
       9 . The expansion valve according to  claim 1 , wherein mounting surface portions via which the expansion valve is mounted on a fire wall member disposed at a boundary between a vehicle compartment and an engine room are formed integrally with the body by the die casting.  
   
   
       10 . The expansion valve according to  claim 1 , wherein flat surface portions serving as holders are integrally formed on sides of the body by the die casting.  
   
   
       11 . The expansion valve according to  claim 3 , wherein flat surface portions serving as holders are integrally formed on sides of the body by the die casting, and 
 wherein the flat surface portions are formed on side surfaces of the body, which are parallel to the first passage and the second passage.    
   
   
       12 . The expansion valve according to  claim 2 , wherein the aluminum alloy contains 9.6 to 12.0 wt % of Si, and 1.5 to 3.5 wt % of Cu.  
   
   
       13 . The expansion valve according to  claim 3 , wherein the first passage is configured such that a portion thereof including a first port for introducing refrigerant from the condenser side, and a portion thereof including a second port for delivering refrigerant having passed through the valve portion to the evaporator, cross each other within the body, while the second passage is configured such that a portion thereof including a third port for introducing refrigerant returning from the evaporator, and a portion thereof including a fourth port for delivering the refrigerant toward the compressor, cross each other within the body.  
   
   
       14 . The expansion valve according to  claim 13 , wherein a side surface of the body where the first port and the fourth port open, and a side surface of the body where the second port and the third port open are orthogonal to each other.  
   
   
       15 . The expansion valve according to  claim 1 , wherein the body has at least one inflated portion integrally formed therewith by the die casting.  
   
   
       16 . The expansion valve according to  claim 15 , wherein the inflated portion is formed with through holes for mounting pipes.  
   
   
       17 . An expansion valve that introduces refrigerant from an upstream side thereof and throttles and expands the refrigerant by passing the refrigerant through a valve section formed therein, to supply the refrigerant to a downstream side thereof, 
 wherein a body having a valve section provided therein is formed by die casting a metal.    
   
   
       18 . The expansion valve according to  claim 17 , which is configured as a temperature expansion valve disposed in a refrigeration cycle, for operation such that the temperature expansion valve throttles and expands refrigerant flowing in from a condenser side by passing the refrigerant through the valve section to supply the refrigerant to an evaporator, controls a valve lift of the valve section by sensing a pressure and a temperature of the refrigerant returning from the evaporator, and delivers the refrigerant to a compressor side, 
 wherein the body has a first passage formed therein for introducing the refrigerant from the condenser side and passing the refrigerant through the valve section to deliver the refrigerant to the evaporator, the first passage having the valve section provided in an intermediate portion thereof, and a second passage formed therein for introducing the refrigerant returning from the evaporator and delivering the refrigerant to the compressor side, the first and second passages being formed substantially by the die casting, and    the expansion valve comprising a power element provided on the body on a side of the second passage, opposite from the first passage, for sensing a temperature and a pressure of refrigerant flowing through the second passage, and controlling a valve lift of the valve section provided in the first passage, via a shaft, to thereby control a flow rate of refrigerant delivered to the evaporator.    
   
   
       19 . The expansion valve according to  claim 18 , wherein the first passage includes: 
 an introduction passage for introducing refrigerant from the condenser side;    a delivery passage for delivering the refrigerant to the evaporator; and    a valve hole formed between the introduction passage and the delivery passage for connection thereof.    
   
   
       20 . The expansion valve according to  claim 18 , including a valve seat-forming member for forming a valve seat as a component part of the valve section, or having the valve seat formed therein, 
 wherein the valve seat-forming member is formed in advance, and is insert-molded into the body by the die casting.    
   
   
       21 . The expansion valve according to  claim 18 , including a valve seat-forming member for forming a valve seat as a component part of the valve section, or having the valve seat formed therein, 
 wherein the valve seat-forming member is formed in advance, and assembled to a location of the valve section of the body formed by the die casting.    
   
   
       22 . The expansion valve according to  claim 17 , including a connection bolt partially insert-molded into the body by the die casting such that the connection bolt protrudes outward from the body.  
   
   
       23 . The expansion valve according to  claim 17 , wherein the metal is an aluminum alloy.  
   
   
       24 . The expansion valve according to  claim 17 , wherein a pin for positioning a joint which is interposed between the body and a pipe when the pipe is connected to the body is formed integrally with the body by the die casting.  
   
   
       25 . The expansion valve according to  claim 24 , wherein the pin is formed in a manner protruding from an inflated portion which is formed integrally with the body by the die casting.  
   
   
       26 . The expansion valve according to  claim 17 , wherein a refrigerant leakage passage for ensuring a flow of refrigerant flowing from an upstream side to a downstream side at a predetermined flow rate even when the valve section is closed is formed integrally with the body by the die casting in at least one of a valve hole of the valve section and a vicinity of the valve hole.  
   
   
       27 . The expansion valve according to  claim 26 , wherein the refrigerant leakage passage is a bleed hole formed in the vicinity of the valve hole.  
   
   
       28 . The expansion valve according to  claim 26 , wherein the refrigerant leakage passage is a nicked seat comprising a groove portion formed continuous with the valve hole of the valve section, and forms, when a valve element of the valve section is seated on a valve seat of the valve section, a predetermined gap communicating with the valve hole, between the valve element and the valve seat.  
   
   
       29 . The expansion valve according to  claim 17 , wherein the die casting of a metal is carried out by a semi-solid die casting process.  
   
   
       30 . The expansion valve according to  claim 29 , wherein the body is formed by injecting a semi-solid metal slurry composed of spherical particles into a predetermined mold.  
   
   
       31 . The expansion valve according to  claim 30 , wherein a metal slurry of which the spherical particles have an average particle diameter of not less than 10 μm and not more than 60 μm is used as the metal slurry.  
   
   
       32 . The expansion valve according to  claim 30 , wherein the metal slurry is made of an aluminum alloy containing 6.5 to 12.0 wt % of Si.  
   
   
       33 . The expansion valve according to  claim 30 , wherein as the metal slurry, there is used a metal slurry formed to be in a solid-liquid coexistent state, by pouring a molten metal into a predetermined container while applying an electromagnetic field thereto to thereby inhibit formation of dendritic crystals, and cooling the molten metal after termination of the application of the electromagnetic field to the container.  
   
   
       34 . The expansion valve according to  claim 33 , wherein the metal slurry has the spherical particles thereof formed by agitating the molten metal in the container during application of the electromagnetic field to thereby inhibit formation of dendritic crystals.  
   
   
       35 . The expansion valve according to  claim 33 , wherein the metal slurry is formed by terminating the application of the electromagnetic field when the solid phase ratio of the molten metal is not less than 0.001 and not more than 0.1.  
   
   
       36 . The expansion valve according to  claim 35 , wherein the metal slurry is formed by terminating the cooling of the molten metal when the solid phase ratio of the molten metal is not less than 0.1 and not more than 0.7.  
   
   
       37 . The expansion valve according to  claim 17 , wherein a metal of the body is composed of spherical metal particles having a particle diameter of not less than 10 μm and not more than 60 μm.  
   
   
       38 . The expansion valve according to  claim 37 , wherein the body is formed by die casting using a semi-solid metal slurry.