A refrigeration cycle (1) comprises in the direction of flow of a circulating refrigerant: a compressor unit (2); an oil separation device (4) which is configured for separating oil from an refrigerant-oil-mixture leaving the compressor unit (2); at least one gas cooler/condenser (6); and at least one evaporator (10) having an expansion device (8) connected upstream thereof. The oil separation device (4, 5) comprises: a refrigerant inlet line connected to the compressor unit (2), the refrigerant inlet line having at least a first portion (12) with a first diameter (d1); a refrigerant conduit arranged downstream of and connected to the refrigerant inlet line, the refrigerant conduit having at least a second portion (14) with a second diameter (d2), which is larger than the first diameter (d1); a refrigerant outlet line arranged downstream of and connected to the refrigerant conduit, the refrigerant outlet line having at least a third portion (16) with a third diameter (d3), which is smaller than the second diameter (d2); and an oil suction line (20) having an inlet portion (22) which opens into the second portion (14) and is configured for sucking oil from the second portion (16). The third portion (16) having the third diameter (d2) extends into the second portion (14) forming an oil separation pocket (18) between the outer diameter of the third portion (16) and the inner diameter of the second portion (14).