Cryocooler and rotary valve mechanism

Abstract

A rotary valve mechanism includes a stator valve member furnished with one of either a dome-shaped high-pressure recess area made of a polymer or a high-pressure flow path made of metal, and a rotor valve member furnished with the other of either the dome-shaped high-pressure recess area made of a polymer or the high-pressure flow path made of metal, and seals a high-pressure region being the high-pressure flow path communicated with the dome-shaped high-pressure recess area and is disposed adjoining the stator valve member such as to isolate the high-pressure region from its low-pressure surrounding environs.

What is claimed is: 
     
         1 . A cryocooler comprising:
 a working gas compressor provided with a compressor expulsion port and a compressor suction port;   an expander provided with a gas expansion chamber and a low-pressure gas chamber communicated with the compressor suction port;   a stator valve member disposed in the low-pressure gas chamber, and provided with a stator-side rotary sliding surface, a high-pressure gas inlet port opening on the stator-side rotary sliding surface and communicated with the compressor expulsion port, and a gas venting port opening on the stator-side rotary sliding surface and communicated with the gas expansion chamber; and   a rotor-valve polymer member disposed in the low-pressure gas chamber such as to rotate about an axis with respect to the stator valve member and configured such as to isolate a rotor valve high-pressure recess area from the low-pressure gas chamber, the rotor valve high-pressure recess area being formed such as to communicate the high-pressure gas inlet port with the gas venting port in a portion of a single cycle of rotation of the rotor-valve polymer member and to cut off the high-pressure gas inlet port from the gas venting port in the remainder of the single cycle; wherein   the rotor-valve polymer member includes
 a rotor-valve outer peripheral surface facing the low-pressure gas chamber, 
 a rotor-side rotary sliding surface surrounding the rotor valve high-pressure recess area, and in surface-contact with the stator-side rotary sliding surface, 
 a recess-area bottom wall surface facing the rotor valve high-pressure recess area, 
 a recess-area peripheral wall surface forming a recess-area contour line on the rotor-side rotary sliding surface and extending from the recess-area contour line and directed toward the recess-area bottom wall surface, the polymer's thickness toward the rotor-valve outer peripheral surface varies running along the recess-area contour line, and 
 a first thin-walled polymer portion having a first minimum polymer thickness from the recess-area peripheral wall surface to the rotor valve outer peripheral surface, and including a first inclination join region connecting the recess-area bottom wall surface to the recess-area peripheral wall surface and being inclined with respect to both the recess-area bottom wall surface and the recess-area peripheral wall surface. 
   
     
     
         2 . The cryocooler according to  claim 1 , wherein:
 the rotor-valve polymer member is configured such as to isolate the rotor-valve high-pressure recess area from a rotor-valve opening area, the rotor valve opening area being formed such that the gas venting port is communicated with the low-pressure gas chamber in at least a portion of the remainder of the single cycle; and   the rotor-valve polymer member is furnished with a second thin-walled polymer portion having a second minimum polymer thickness from the recess-area peripheral wall surface to the rotor-valve opening area, and includes a second inclination join region connecting the recess-area bottom wall surface to the recess-area peripheral wall surface and is inclined with respect to both the recess-area bottom wall surface and the recess-area peripheral wall surface.   
     
     
         3 . The cryocooler according to  claim 2 , wherein the rotor valve polymer member includes a fillet surface connecting the recess-area bottom wall surface to the recess-area peripheral wall surface over the entire periphery of the recess-area peripheral wall surface, and the first inclination joint region and the second inclination joint region each configure a portion of the fillet surface. 
     
     
         4 . The cryocooler according to  claim 3 , wherein the recess-are contour line includes at least one arcuate section, and the fillet surface has a fillet radius that is smaller than the arcuate section's radius. 
     
     
         5 . The cryocooler according to  claim 4 , wherein the fillet radius is greater than 1/10 of the radius of the arcuate section. 
     
     
         6 . The cryocooler according to  claim 3 , wherein:
 the rotor valve polymer member is formed of a fluoropolymer material; and   the fillet surface has a fillet radius determined such that the maximum value of von Mises stress acting on the recess-area peripheral wall surface is less than ⅓ of tensile strength of the fluoropolymer material.   
     
     
         7 . The cryocooler according to  claim 1 , wherein the recess-area bottom wall surface determines the maximum depth of the rotor-valve high-pressure recess area from the rotor-side rotary sliding surface, and the first minimum polymer thickness is less than the maximum depth. 
     
     
         8 . The cryocooler according to  claim 1 , wherein:
 the high-pressure gas inlet port is located in a central area along the stator-side rotary sliding surface, and the gas venting port is located radially outward with respect to the high-pressure gas inlet port along the stator-side rotary sliding surface; and   the recess-area contour line includes two linear sections extending radially outward from the central area along the rotor-side rotary sliding surface, and an interval between the two linear sections gradually widens radially outward from the central area.   
     
     
         9 . A cryocooler rotary valve mechanism comprising:
 a stator valve member disposed in a low-pressure gas chamber of a cryocooler, and provided with a stator-side rotary sliding surface, a high-pressure gas inlet port opening on the stator-side rotary sliding surface, and a gas venting port opening on the stator-side rotary sliding surface; and   a rotor-valve polymer member disposed in the low-pressure gas chamber such as to rotate about an axis with respect to the stator valve member and configured such as to isolate a rotor valve high-pressure recess area from the low-pressure gas chamber, the rotor valve high-pressure recess area being formed such as to communicate the high-pressure gas inlet port with the gas venting port in a portion of a single cycle of rotation of the rotor-valve polymer member and to cutoff the high-pressure gas inlet port from the gas venting port in the remainder of the single cycle; wherein   the rotor-valve polymer member includes
 a rotor-valve outer peripheral surface facing the low-pressure gas chamber, 
 a rotor-side rotary sliding surface surrounding the rotor valve high-pressure recess area, and in surface-contact with the stator-side rotary sliding surface, 
 a recess-area bottom wall surface facing the rotor valve high-pressure recess area, 
 a recess-area peripheral wall surface forming a recess-area contour line on the rotor-side rotary sliding surface and extending from the recess-area contour line and directed toward the recess-area bottom wall surface, the polymer's thickness toward the rotor-valve outer peripheral surface varies running along the recess-area contour line, and 
 a thin-walled polymer portion having a minimum polymer thickness from the recess-area peripheral wall surface to the rotor valve outer peripheral surface, and including a first inclination join region connecting the recess-area bottom wall surface to the recess-area peripheral wall surface and being inclined with respect to both the recess-area bottom wall surface and the recess-area peripheral wall surface. 
   
     
     
         10 . A rotary valve mechanism comprising:
 a stator valve member furnished with one of either a dome-shaped high-pressure recess area made of a polymer or a high-pressure flow path made of metal; and   a rotor valve member furnished with the other of either the dome-shaped high-pressure recess area made of a polymer or the high-pressure flow path made of metal, and seals a high-pressure region being the high-pressure flow path communicated with the dome-shaped high-pressure recess area and is disposed adjoining the stator valve member such as to isolate the high-pressure region from its low-pressure surrounding environs.