Reciprocating compressor with a linear motor

Abstract

A reciprocating compressor having a linear motor, at least one piston and cylinder arrangement and a mechanism operatively connecting the linear motor to the piston and cylinder arrangement is provided. The piston and cylinder arrangement operate to compress a fluid, preferably a refrigerant gas. The piston and cylinder arrangement has a cylinder, a piston configured and disposed to travel in the cylinder and a piston rod connected to the piston. The mechanism connects the linear motor to the piston rod to move the piston in the cylinder upon operation of the linear motor. The mechanism is configured and disposed to limit overtravel of the piston in the cylinder in response to a light load of the reciprocating compressor and to limit undertravel of the piston in the cylinder in response to a heavy load in the reciprocating compressor. The mechanism connecting the linear motor to the piston and cylinder arrangement can include a connecting rod and eccentric, a cam mechanism, a wobble plate mechanism, a gear mechanism, or a track mechanism.

1 . A reciprocating compressor comprising: 
 a linear motor;    at least one piston and cylinder arrangement, the piston and cylinder arrangement comprising a cylinder, a piston configured and disposed to travel in the cylinder and a piston rod connected to the piston; and    a mechanism operatively connecting the linear motor to the at least one piston and cylinder arrangement to move the piston in the cylinder upon operation of the linear motor, the mechanism having a mechanical configuration to limit overtravel and undertravel of the piston in the cylinder.    
     
     
         2 . The compressor of  claim 1  wherein the mechanism comprises a connecting rod and eccentric.  
     
     
         3 . The compressor of  claim 1  wherein the mechanism comprises a cam mechanism.  
     
     
         4 . The compressor of  claim 1  wherein the mechanism comprises a wobble plate mechanism.  
     
     
         5 . The compressor of  claim 1  wherein the mechanism comprises a gear mechanism.  
     
     
         6 . The compressor of  claim 5 , wherein the gear mechanism comprises a linear gear connected to the linear motor.  
     
     
         7 . The compressor of  claim 6 , wherein the linear gear comprises at least one gear surface, the gear mechanism comprises at least one connecting gear to contact the at least one gear surface of the linear gear, the at least one connecting gear being connected to a piston rod, and the at least one gear surface being configured to provide a pre-determined and controlled travel path for the piston rod and piston.  
     
     
         8 . The compressor of  claim 7 , wherein the gear surface is substantially parallel with the longitudinal axis of the linear gear.  
     
     
         9 . The compressor of  claim 8 , wherein the gear surface is selected from the group consisting of square-toothed, grooved, and serrated.  
     
     
         10 . The compressor of  claim 1 , wherein the mechanism is a track mechanism.  
     
     
         11 . The compressor of  claim 10 , wherein the track mechanism includes a drive block having an embedded track, a drive pin at least partially disposed in the embedded track and connected to the linear motor and one or more piston rods, the drive pin being configured to move in the track to move the one or more piston rods in response to operation of the linear motor.  
     
     
         12 . The compressor of  claim 1  wherein the track has a shape and slope to permit the drive pin to smoothly engage one or more piston rods to drive the corresponding pistons up and down in the cylinder and the track is configured to provide a predetermined and controlled travel path for the one or more piston rods and pistons.  
     
     
         13 . The compressor of  claim 12 , wherein the travel path includes a constant predetermined top-dead center piston position and bottom-dead center piston position.  
     
     
         14 . The compressor of  claim 13 , wherein the track comprises at least one substantially horizontal non-sloped track section corresponding to the top dead center piston position and to the bottom dead center piston position, wherein the piston is relatively motionless in the cylinder until the pin is pulled or pushed back into the sloped portion of the track by the linear motor.  
     
     
         15 . A mechanism to connect a linear motor to a piston-cylinder arrangement, the mechanism having a mechanical configuration to limit overtravel and undertravel of the piston in the cylinder.  
     
     
         16 . The mechanism of  claim 15  wherein the mechanism comprises a connecting rod and eccentric.  
     
     
         17 . The mechanism of  claim 16  wherein the mechanism comprises a cam mechanism.  
     
     
         18 . The mechanism of  claim 17  wherein the mechanism comprises a wobble plate mechanism.  
     
     
         19 . The mechanism of  claim 18  wherein the mechanism comprises a gear mechanism.  
     
     
         20 . The mechanism of  claim 19 , wherein the gear mechanism comprises a linear gear connected to the linear motor.  
     
     
         21 . The mechanism of  claim 20 , wherein the linear gear comprises at least one gear surface, the gear mechanism comprises at least one connecting gear to contact the at least one gear surface of the linear gear, the at least one connecting gear being connected to a piston rod, and the at least one gear surface being configured to provide a pre-determined and controlled travel path for the piston rod and piston.  
     
     
         22 . The mechanism of  claim 21 , wherein the at least one gear surface is substantially parallel with the longitudinal axis of the linear gear.  
     
     
         23 . The mechanism of  claim 22 , wherein the at least one gear surface is selected from the group consisting of square-toothed, grooved, and serrated.  
     
     
         24 . The mechanism of  claim 15 , wherein the mechanism is a track mechanism.  
     
     
         25 . The mechanism of  claim 24 , wherein the track mechanism includes a drive block having an embedded track, a drive pin at least partially disposed in the embedded track and connected to the linear motor and one or more piston rods, the drive pin being configured to move in the track to move the one or more piston rods in response to operation of the linear motor.  
     
     
         26 . The mechanism of  claim 25 , wherein the track has a shape and slope to permit the drive pin to smoothly engage one or more piston rods to drive the corresponding pistons up and down in the cylinder and the track is configured to provide a predetermined and controlled travel path for the one or more piston rods and pistons.  
     
     
         27 . The mechanism of  claim 26 , wherein the travel path includes a constant predetermined top-dead center piston position and bottom-dead center piston position.  
     
     
         28 . The mechanism of  claim 27 , wherein the track comprises at least one substantially horizontal non-sloped track section corresponding to the top dead center piston position and to the bottom dead center piston position, wherein the piston is relatively motionless in the cylinder until the pin is pulled or pushed back into the sloped portion of the track by the linear motor.