Reciprocating Piston Machine, in Particular a Compressor for a Vehicle Air-Conditioning Unit

Abstract

A reciprocating piston machine ( 100 ) is provided such as a CO 2 compressor for a vehicle air-conditioning unit. The machine ( 100 ) comprises a plurality of pistons and a swivel disk ( 107 ) that is rotated by and can be positioned at an adjustable angle with respect to a drive shaft ( 104 ). The swivel disk ( 107 ) is mounted on the drive shaft ( 104 ) so as to be axially movable thereon. In addition, the swivel disk is connected in an articulated manner to at least one supporting element ( 109 ) which is disposed so that it is spaced apart from the drive shaft ( 104 ) but rotates therewith. Each of the pistons ( 106 ) comprises a joint arrangement ( 110 ) with which the swivel disk ( 107 ) is in sliding engagement. The connection ( 116 ) between the drive shaft ( 104 ) and the swivel disk ( 107 ) serves substantially only to transmit torque, whereas the supporting element ( 109 ) serves substantially only to provide axial support to the pistons ( 106 ) and/or to the swivel disk ( 107 ) and hence to absorb the force exerted by the gas.

1 . A reciprocating piston machine ( 100 ) comprising a plurality of pistons and a swivel disk ( 107 ) that is rotated by a drive shaft ( 104 ) and that is positioned at an adjustable angle with respect to the drive shaft ( 104 ), the disk ( 107 ) being mounted on the drive shaft ( 104 ) so as to be axially movable thereon and being connected in an articulated manner to at least one supporting element ( 109 ) so disposed that it is spaced apart from the drive shaft ( 104 ) but rotates therewith, and each of the pistons ( 106 ) comprising a joint arrangement ( 110 ) with which the swivel disk ( 107 ) is in sliding engagement, characterized in that the connection ( 116 ) between the drive shaft ( 104 ) and the swivel disk ( 107 ) serves substantially only to transmit torque, and the supporting element ( 109 ) serves substantially only to provide axial support to the pistons ( 106 ) and/or to the swivel disk ( 107 ) and hence to absorb the force exerted by the gas. 
   
   
       2 . A machine ( 100 ) as claimed in  claim 1 , characterized in that the disk ( 107 ) is mounted on the drive shaft ( 104 ) by means of a sleeve ( 108 ,  133 ) or corresponding element to which it is connected in an articulated manner. 
   
   
       3 . A machine ( 100 ) as claimed in  claim 2 , characterized in that the sleeve ( 108 ) or corresponding element, such as a bolt, is axially movable along the drive shaft ( 104 ) either around or within the said drive shaft. 
   
   
       4 . A machine ( 100 ) as claimed in  claim 1 , characterized in that the supporting element ( 109 ) is constructed with a spherical, cylindrical or barrel-shaped ( 129 ) profile. 
   
   
       5 . A machine ( 100 ) as claimed in  claim 4 , characterized in that the supporting element has a barrel-shaped longitudinal profile and a substantially spoon-shaped transverse cross-sectional profile. 
   
   
       6 . A machine as claimed in  claim 1 , characterized in that the swivel disk ( 107 ) comprises a recess ( 115 ,  130 ) that defines a space in which the supporting element ( 109 ) is engaged, the long axis of the recess being oriented radially while its longer cross-sectional axis extends in the circumferential direction. 
   
   
       7 . A machine ( 100 ) as claimed in  claim 6 , characterized in that the recess ( 130 ) formed in the swivel disk ( 107 ) that does not extend all the way through the swivel disk and is blind. 
   
   
       8 . A machine ( 100 ) as claimed in  claim 1 , characterized in that the swivel disk ( 107 ) comprises at least one axial extension ( 131 ) in one or both axial directions. 
   
   
       9 . A machine ( 100 ) as claimed in  claim 1 , characterized in that the supporting element ( 109 ) is connected to the drive shaft ( 104 ) by means of a rod-like force-transmission element ( 114 ). 
   
   
       10 . A machine as claimed in  claim 9 , characterized in that the force-transmission element ( 114 ) projects away from the drive shaft ( 104 ) at an angle, so that when the swivel disk ( 107 ) is tilted at an intermediate position, the rod-axis is oriented radially with respect to the swivel disk ( 107 ). 
   
   
       11 . A machine as claimed in  claim 9 , characterized in that force-transmitting element ( 114 ) is weighted to ensure that its centre of mass coincides with the axis of the drive shaft ( 104 ). 
   
   
       12 . A machine ( 100 ) as claimed in  claim 1 , characterized in that the supporting element ( 109 ) is disposed at the free end of an L-shaped forcetransmitting element ( 114 ), one limb ( 126 ) of which extends approximately parallel to the drive shaft ( 104 ) and is supported axially against a bearing plate ( 127 ) that is nonrotatably connected to the drive shaft ( 104 ). 
   
   
       13 . A machine as claimed in  claim 1 , characterized in that the centre ( 122 ) of the supporting element ( 109 ) lies on a circular line that either coincides with the circle on which the midpoints of the piston-joint arrangements ( 110 ) lie or extends radially slightly beyond said circle. 
   
   
       14 . A machine as claimed in  claim 1 , characterized in that two supporting elements ( 109 ) are provided, which provide support in axially opposite directions.