Piezoelectric Pump and Stirling Refrigerator/Freezer

Abstract

A piezoelectric pump includes a casing formed of a plurality of metallic members welded and thus joined together, a piezoelectric element dividing an internal space of the casing into a working space and a back pressure space, and internal components formed of resin, and provided between the casing and the piezoelectric element and holding the piezoelectric element. The internal components are formed of workable and moldable resin. The internal component defines a perimeter of the working space and the internal component defines a perimeter of the back pressure space. The internal components are arranged opposite each other to form a recess therebetween to receive and thus hold the piezoelectric element therein.

1 . A piezoelectric pump comprising:
 a casing formed of a plurality of metallic members joined together;   a piezoelectric element dividing an internal space of said casing into first and second internal spaces; and   non-metallic, first and second internal components provided between said casing and said piezoelectric element and holding said piezoelectric element.   
   
   
       2 . The piezoelectric pump according to  claim 1 , wherein:
 said first and second internal components are formed of resin;   said first and second internal components define perimeters of said first and second internal spaces, respectively; and   said piezoelectric element is sandwiched to be held between said first and second internal components.   
   
   
       3 . The piezoelectric pump according to  claim 1 , further comprising:
 an inlet provided on said first internal component and passing a working medium flowing from an aspiration pipe external to said casing toward said first internal space serving as a working space;   an outlet provided on said first internal component and passing the working medium flowing from said first internal space toward a discharge pipe external to said casing;   a first check valve provided between said inlet and said first internal space;   a second check valve provided between said outlet and said first internal space; and   a plurality of O rings sealing a gap formed between said first and second internal spaces and said piezoelectric element and a gap formed between said inlet and said outlet and said casing, respectively, wherein said first internal component has portions at which said first and second check valves are set, respectively, and a plurality of grooves accommodating said plurality of O rings, respectively.   
   
   
       4 . The piezoelectric pump according to  claim 3 , further comprising a communication portion allowing said second internal space serving as a back pressure space to communicate with one of said inlet and said outlet, wherein said communication portion is defined by one of a bore and a groove formed in said first and second internal components. 
   
   
       5 . The piezoelectric pump according to  claim 3 , provided with a communication bore allowing one of said inlet and said outlet to communicate with such portions of said metallic members that are joined together. 
   
   
       6 . The piezoelectric pump according to  claim 1 , comprising:
 a first inlet provided on said first internal component and passing the working medium flowing from a first aspiration pipe external to said casing toward said first internal space serving as a working space;   a second inlet provided on said second internal component and passing the working medium flowing from a second aspiration pipe external to said casing toward said second internal space serving as a working space;   a first outlet provided on said first internal component and passing the working medium flowing from said first internal space toward a first discharge pipe external to said casing;   a second outlet provided on said second internal component and passing the working medium flowing from said second internal space toward a second discharge pipe external to said casing;   first and second check valves provided between said first and second inlets and said first and second internal spaces, respectively;   third and fourth check valves provided between said first and second outlets and said first and second internal spaces, respectively; and   a plurality of O rings sealing a gap formed between said first and second internal spaces and said piezoelectric element and a gap formed between said first and second inlets and said first and second outlets and said casing, respectively, wherein said first and second internal components have portions at which said first to fourth check valves are set, respectively, and a plurality of grooves accommodating said plurality of O rings, respectively.   
   
   
       7 . The piezoelectric pump according to  claim 6 , provided with a communication bore allowing one of said first and second inlets and said first and second outlets to communicate with such portions of said metallic members that are joined together. 
   
   
       8 . The piezoelectric pump according to  claim 1 , comprising:
 a first inlet provided on said first internal component and passing the working medium flowing from an aspiration pipe external to said casing toward said first internal space serving as a working space;   a second inlet provided on said second internal component and passing the working medium flowing from said first inlet toward said second internal space;   a first outlet provided on said first internal component and passing the working medium flowing from said first internal space toward a discharge pipe external to said casing;   a second outlet provided on said second internal component and passing the working medium flowing from said second internal space toward said first outlet;   a first communication portion defined by one of a bore and a groove formed in said first and second internal components to allow said first and second inlets to communicate with each other;   a second communication portion defined by one of a bore and a groove formed in said first and second internal components to allow said first and second outlets to communicate with each other;   first and second check valves provided between said first and second inlets and said first and second internal spaces, respectively;   third and fourth check valves provided between said first and second outlets and said first and second internal spaces, respectively; and   a plurality of O rings sealing a gap formed between said first and second internal spaces and said piezoelectric element and a gap formed between said first and second inlets and said first and second outlets and said casing, respectively, wherein   said first and second internal components have portions at which said first to fourth check valves are set, respectively, and a plurality of grooves accommodating said plurality of O rings, respectively.   
   
   
       9 . A Stirling refrigerator/freezer having the piezoelectric pump of  claim 1  at a working-medium circulation circuit associated with a warm portion.