Piston type compressor

Abstract

A rotary valve is used as a suction valve mechanism of a compressor. The rotary valve rotates integrally with a drive shaft to selectively open or close a suction passage of refrigerant gas from a suction chamber to a compression chamber in accordance with relative positions of the suction communicating passage and the suction guiding groove. An outer surface of the rotary valve directly slides on an inner surface of a valve accommodating chamber formed in a cylinder block, thereby constituting a slide bearing surface. The slide bearing surface rotatably supports the rear end of the drive shaft on housings. Accordingly, a piston type compressor which is comfortably used, inexpensively manufactured, and has high compression efficiency is provided.

1 . A piston type compressor comprising a drive shaft rotatably supported on a housing, the housing including a cylinder block, the cylinder block including a cylinder bore and a valve accommodating chamber, wherein reciprocation of a piston operably connected to the drive shaft in the corresponding cylinder bore changes the volume of a compression chamber in the cylinder bore to compress gas supplied from a first region, on which a suction pressure acts, to the compression chamber, wherein the compressed gas is sent to a second region, on which a discharge pressure acts, the compressor comprising: 
 a rotary valve accommodated in the valve accommodating chamber, wherein the rotary valve rotates integrally with the drive shaft to selectively open or close a passage of gas from the first pressure region to the compression chamber, wherein the rotary valve has a substantially cylindrical shape and an outer surface, wherein the valve accommodating chamber has a circular cross-section and an inner surface, wherein the outer surface and the inner surface constitute slide bearing surfaces for receiving a radial load applied to the drive shaft by sliding on each other.    
     
     
         2 . The piston type compressor according to  claim 1 , wherein the outer surface of the rotary valve and the inner surface of the valve accommodating chamber are tilted with respect to the axis of the drive shaft, and the slide bearing surfaces also receive a thrust load acting on the drive shaft.  
     
     
         3 . The piston type compressor according to  claim 2 , wherein the tilted portions are provided away from a part of the refrigerant gas passage that is opened and closed by the rotary valve.  
     
     
         4 . The piston type compressor according to  claim 2 , wherein the outer surface of the rotary valve and the inner surface of the valve accommodating chamber are tilted in such a direction as to approach the axis of the drive shaft toward the rear side of the compressor, and are tapered.  
     
     
         5 . The piston type compressor according to  claim 2 , wherein at least a part of the outer surface of the rotary valve and a part of the inner surface of the valve accommodating chamber are tapered.  
     
     
         6 . The piston type compressor according to  claim 5 , wherein the tapered portions are provided away from a part of the refrigerant gas passage that is opened and closed by the rotary valve.  
     
     
         7 . The piston type compressor according to  claim 6 , further comprising a plurality of suction communicating passages, wherein the compression chamber is one of a plurality of compression chambers, wherein each suction communicating passage corresponds to one of the compression chambers, wherein the valve accommodating chamber and each compression chamber are communicated with each other through the corresponding suction communicating passage, wherein the rotary valve has a suction guiding groove which is communicated with the first region, wherein the tapered portion of the outer surface of the rotary valve is provided at the rear of an opening of the suction guiding groove, and the tapered portion of the inner surface of the valve accommodating chamber is provided at the rear of openings of the suction communicating passages.  
     
     
         8 . The piston type compressor according to  claim 2 , wherein at least a part of the outer surface of the rotary valve and a part of the inner surface of the valve accommodating chamber are curved.  
     
     
         9 . The piston type compressor according to  claim 8 , wherein the curved portions are provided away from a part of the refrigerant gas passage that is opened and closed by the rotary valve.  
     
     
         10 . The piston type compressor according to  claim 9 , further comprising a plurality of suction communicating passages, wherein the compression chamber is one of a plurality of compression chambers, wherein each suction communicating passage corresponds to one of the compression chambers, wherein the valve accommodating chamber and each compression chamber are communicated with each other through the corresponding suction communicating passage, wherein the rotary valve has a suction guiding groove which is communicated with the first region, wherein the curved portion of the outer surface of the rotary valve is provided at the rear of an opening of the suction guiding groove, and the curved portion of the inner surface of the valve accommodating chamber is provided at the rear of openings of the suction communicating passages.  
     
     
         11 . The piston type compressor according to  claim 1 , wherein the rotary valve has a larger diameter than the drive shaft.  
     
     
         12 . The piston type compressor according to  claim 1 , wherein the drive shaft and the rotary valve are separately provided.  
     
     
         13 . The piston type compressor according to  claim 1 , wherein the drive shaft and the rotary valve are integrally provided.  
     
     
         14 . The piston type compressor according to  claim 1 , wherein, on at least one of the outer surface of the rotary valve and the inner surface of the valve accommodating chamber, a coating is provided for improving sliding characteristics between the surfaces.  
     
     
         15 . The piston type compressor according to  claim 1 , wherein a pumping groove is provided on the outer surface of the rotary valve or the inner surface of the valve accommodating chamber to pump at least one of refrigerant gas and lubricating oil contained in the refrigerant gas by rotation of the rotary valve.  
     
     
         16 . The piston type compressor according to  claim 1 , wherein the rotary valve includes supercharging means for actively supplying the refrigerant gas to the compression chamber by using rotational force of the valve.  
     
     
         17 . The piston type compressor according to  claim 1 , wherein the rotary valve further includes a hole for communicating a discharge pressure region with a clearance between the rotary valve and the valve accommodating chamber.  
     
     
         18 . The piston type compressor according to  claim 17 , wherein the hole is arranged in a region opposite the suction guiding groove with respect to the axis of the drive shaft.  
     
     
         19 . The piston type compressor according to  claim 1 , wherein the cylinder block and the rotary valve are made of materials having coefficients of thermal expansion equal to or close to each other.  
     
     
         20 . A piston type compressor comprising a drive shaft rotatably supported on a housing, the housing including a cylinder block, the cylinder block including a cylinder bore and a valve accommodating chamber communicating with a suction communicating passage, wherein reciprocation of a piston operably connected to the drive shaft in the corresponding cylinder bore changes the volume of a compression chamber in the cylinder bore to compress gas supplied from a first region through the suction communicating passage, on which a suction pressure acts, to the compression chamber, wherein the compressed gas is sent to a second region, on which a discharge pressure acts, the compressor comprising: 
 a rotary valve accommodated in the valve accommodating chamber, wherein the rotary valve has a suction guiding groove which is communicated with the first region, wherein the rotary valve rotates integrally with the drive shaft to selectively open or close a passage of gas from the first pressure region to the compression chamber in accordance with relative positions of the suction communicating passage and the suction guiding groove, wherein the rotary valve has a substantially cylindrical shape and an outer surface, wherein the valve accommodating chamber has a circular cross-section and an inner surface, wherein the outer surface and the inner surface constitute slide bearing surfaces for receiving a radial load applied to the drive shaft by sliding on each other.