{
  "url": "https://openlegislation.uk/eu-regulation-2017-2400/annex-VI/appendix-6",
  "json_url": "https://openlegislation.uk/eu-regulation-2017-2400/annex-VI/appendix-6.json",
  "legislation": "eur/2017/2400",
  "legislation_title": "Commission Regulation (EU) 2017/2400 of 12 December 2017 implementing Regulation (EC) No 595/2009 of the European Parliament and of the Council as regards the determination of the CO2 emissions and fuel consumption of heavy-duty vehicles and amending Directive 2007/46/EC of the European Parliament and of the Council and Commission Regulation (EU) No 582/2011 (Text with EEA relevance)",
  "legislation_url": "https://openlegislation.uk/eu-regulation-2017-2400",
  "path": "annex/VI/appendix/6",
  "kind": "appendix",
  "number": "6",
  "heading": null,
  "text": "Family Concept\n1.\nGeneral\nA transmission, torque converter, other torque transferring components or additional driveline components family is characterized by design and performance parameters. These shall be common to all members within the family. The manufacturer may decide which transmission, torque converter, other torque transferring components or additional driveline components belong to a family, as long as the membership criteria listed in this Appendix are respected. The related family shall be approved by the Approval Authority. The manufacturer shall provide to the Approval Authority the appropriate information relating to the members of the family.\n1.1\nSpecial cases\nIn some cases there may be interaction between parameters. This shall be taken into consideration to ensure that only transmissions, torque converter, other torque transferring components or additional driveline components with similar characteristics are included within the same family. These cases shall be identified by the manufacturer and notified to the Approval Authority. It shall then be taken into account as a criterion for creating a new transmission, torque converter, other torque transferring components or additional driveline components family.\nIn case of devices or features, which are not listed in paragraph 9. and which have a strong influence on the level of performance, this equipment shall be identified by the manufacturer on the basis of good engineering practice, and shall be notified to the Approval Authority. It shall then be taken into account as a criterion for creating a new transmission, torque converter, other torque transferring components or additional driveline components family.\n1.2\nThe family concept defines criteria and parameters enabling the manufacturer to group transmission, torque converter, other torque transferring components or additional driveline components into families and types with similar or equal CO2-relevant data.\n2.\nThe Approval Authority may conclude that the highest torque loss of the transmission, torque converter, other torque transferring components or additional driveline components family can best be characterized by additional testing. In this case, the manufacturer shall submit the appropriate information to determine the transmission, torque converter, other torque transferring components or additional driveline components within the family likely to have the highest torque loss level.\nIf members within a family incorporate other features which may be considered to affect the torque losses, these features shall also be identified and taken into account in the selection of the parent.\n3.\nParameters defining the transmission family\n3.1\nThe following criteria shall be the same to all members within a transmission family.\n(a)Gear ratio, gearscheme and powerflow (for forward gears only, crawler gears excluded);\n(b)Center distance for countershaft transmissions;\n(c)Type of bearings at corresponding positions (if fitted);\n(d)Type of shift elements (tooth clutches, including synchronisers or friction clutches) at corresponding positions (where fitted).\n3.2\nThe following criteria shall be common to all members within a transmission family. The application of a specific range to the parameters listed below is permitted after approval of the Approval Authority\n(a)Single gear width ± 1 mm;\n(b)Total number of forward gears;\n(c)Number of tooth shift clutches;\n(d)Number of synchronizers;\n(e)Number of friction clutch plates (except for single dry clutch with 1 or 2 plates);\n(f)Outer diameter of friction clutch plates (except for single dry clutch with 1 or 2 plates);\n(g)Surface roughness of the teeth;\n(h)Number of dynamic shaft seals;\n(i)Oil flow for lubrication and cooling per input shaft revolution;\n(j)Oil viscosity (± 10 %);\n(k)System pressure for hydraulically controlled gearboxes;\n(l)Specified oil level in reference to central axis and in accordance with the drawing specification (based on average value between lower and upper tolerance) in static or running condition. The oil level is considered as equal if all rotating transmission parts (except for the oil pump and the drive thereof) are located above the specified oil level;\n(m)Specified oil level (± 1mm).\n4.\nChoice of the parent transmission\nThe parent transmission shall be selected using the following criteria listed below.\n(a)Highest single gear width for Option 1 or highest Single gear width ± 1 mm for Option 2 or Option 3;\n(b)Highest total number of gears;\n(c)Highest number of tooth shift clutches;\n(d)Highest number of synchronizers;\n(e)Highest number of friction clutch plates (except for single dry clutch with 1 or 2 plates);\n(f)Highest value of the outer diameter of friction clutch plates (except for single dry clutch with 1 or 2 plates);\n(g)Highest value for the surface roughness of the teeth;\n(h)Highest number of dynamic shaft seals;\n(i)Highest oil flow for lubrication and cooling per input shaft revolution;\n(j)Highest oil viscosity;\n(k)Highest system pressure for hydraulically controlled gearboxes;\n(l)Highest specified oil level in reference to central axis and in accordance with the drawing specification (based on average value between lower and upper tolerance) in static or running condition. The oil level is considered as equal if all rotating transmission parts (except for the oil pump and the drive thereof) are located above the specified oil level;\n(m)Highest specified oil level (± 1 mm).\n5.\nParameters defining the torque converter family\n5.1\nThe following criteria shall be the same to all members within a torque converter (TC) family.\n5.1.1\nFor hydrodynamic torque converter without mechanical transmission (serial arrangement).\n(a)Outer torus diameter;\n(b)Inner torus diameter;\n(c)Arrangement of pump (P), turbine (T) and stator (S) in flow direction;\n(d)Torus width;\n(e)Oil type according to test specification;\n(f)Blade design;\n5.1.2\nFor hydrodynamic torque converter with mechanical transmission (parallel arrangement).\n(a)Outer torus diameter;\n(b)Inner torus diameter;\n(c)Arrangement of pump (P), turbine (T) and stator (S) in flow direction;\n(d)Torus width;\n(e)Oil type according to test specification;\n(f)Blade design\n(g)Gear scheme and power flow in torque converter mode\n(h)Type of bearings at corresponding positions (if fitted)\n(i)Type of cooling/lubrication pump (referring to parts list)\n(j)Type of shift elements (tooth clutches (including synchronisers) or friction clutches) at corresponding positions where fitted\n5.1.3\nThe following criteria shall be common to all members within a hydrodynamic torque converter with mechanical transmission (parallel arrangement) family. The application of a specific range to the parameters listed below is permitted after approval of the Approval Authority\n(a)Oil level according to drawing in reference to central axis.\n6.\nChoice of the parent torque converter\n6.1\nFor hydrodynamic torque converter without mechanical (serial arrangement) transmission.\nAs long as all criteria listed in 5.1.1 are identical every member of the torque converter without mechanical transmission family can be selected as parent.\n6.2\nFor hydrodynamic torque converter with mechanical transmission.\nThe parent hydrodynamic torque converter with mechanical transmission (parallel arrangement) shall be selected using the following criteria listed below.\n(a)Highest oil level according to drawing in reference to central axis.\n7.\nParameters defining the other torque transferring components (OTTC) family\n7.1\nThe following criteria shall be the same to all members within a hydrodynamic torque transferring components / retarder family.\n(a)Outer torus diameter;\n(b)Torus width;\n(c)Blade design;\n(d)Operating fluid.\n7.2\nThe following criteria shall be the same to all members within a magnetic torque transferring components/retarder family.\n(a)Drum design (electro magnetic retarder or permanent magnetic retarder);\n(b)Outer rotor diameter;\n(c)Cooling blade design;\n(d)Blade design.\n7.3\nThe following criteria shall be the same to all members within a torque transferring components / hydrodynamic clutch family.\n(a)Outer torus diameter;\n(b)Torus width;\n(c)Blade design.\n7.4\nThe following criteria shall be common to all members within a hydrodynamic torque transferring components/retarder family. The application of a specific range to the parameters listed below is permitted after approval of the Approval Authority.\n(a)Outer torus diameter - inner torus diameter (OD-ID);\n(b)Number of blades;\n(c)Operating fluid viscosity (± 50 %).\n7.5\nThe following criteria shall be common to all members within a magnetic torque transferring components / retarder family. The application of a specific range to the parameters listed below is permitted after approval of the Approval Authority.\n(a)Outer rotor diameter - inner rotor diameter (OD-ID);\n(b)Number of rotors;\n(c)Number of cooling blades / blades;\n(d)Number of arms.\n7.6\nThe following criteria shall be common to all members within a torque transferring components / hydrodynamic clutch family. The application of a specific range to the parameters listed below is permitted after approval of the Approval Authority.\n(a)Operating fluid viscosity (± 10 %);\n(b)Outer torus diameter - inner torus diameter (OD-ID);\n(c)Number of blades.\n8.\nChoice of the parent torque transferring component\n8.1\nThe parent hydrodynamic torque transferring component/retarder shall be selected using the following criteria listed below.\n(a)Highest value: outer torus diameter – inner torus diameter (OD-ID);\n(b)Highest number of blades;\n(c)Highest operating fluid viscosity.\n8.2\nThe parent magnetic torque transferring component / retarder shall be selected using the following criteria listed below.\n(a)Highest outer rotor diameter – highest inner rotor diameter (OD-ID);\n(b)Highest number of rotors;\n(c)Highest number of cooling blades/blades;\n(d)Highest number of arms.\n8.3\nThe parent torque transferring component/hydrodynamic clutch shall be selected using the following criteria listed below.\n(a)Highest operating fluid viscosity (± 10 %);\n(b)Highest outer torus diameter – highest inner torus diameter (OD-ID);\n(c)Highest number of blades.\n9.\nParameters defining the additional driveline components family\n9.1\nThe following criteria shall be the same to all members within an additional driveline components/angle drive family family.\n(a)Gear ratio and gearscheme;\n(b)Angle between input/output shaft;\n(c)Type of bearings at corresponding positions\n9.2\nThe following criteria shall be common to all members within an additional driveline components/angle family. The application of a specific range to the parameters listed below is permitted after approval of the Approval Authority.\n(a)Single gear width;\n(b)Number of dynamic shaft seals;\n(c)Oil viscosity (± 10 %);\n(d)Surface roughness of the teeth;\n(e)Specified oil level in reference to central axis and in accordance with the drawing specification (based on average value between lower and upper tolerance) in static or running condition. The oil level is considered as equal if all rotating transmission parts (except for the oil pump and the drive thereof) are located above the specified oil level.\n10.\nChoice of the parent additional driveline component\n10.1\nThe parent additional driveline component / angle drive shall be selected using the following criteria listed below.\n(a)Highest single gear width;\n(a)Highest number of dynamic shaft seals;\n(c)Highest oil viscosity (± 10 %);\n(d)Highest surface roughness of the teeth;\n(e)Highest specified oil level in reference to central axis and in accordance with the drawing specification (based on average value between lower and upper tolerance) in static or running condition. The oil level is considered as equal if all rotating transmission parts (except for the oil pump and the drive thereof) are located above the specified oil level.",
  "extent": "E+W+S+N.I.",
  "status": null,
  "version": "current",
  "annotations": [],
  "outstanding_effects": [],
  "provenance": {
    "source": "legislation.gov.uk",
    "source_url": "https://www.legislation.gov.uk/eur/2017/2400/annex/VI/appendix/6",
    "retrieved_at": "2026-11-01T14:44:20.922900+00:00"
  },
  "licence": "Open Government Licence v3.0",
  "licence_url": "https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/",
  "attribution": "Contains public sector information licensed under the Open Government Licence v3.0. Source: legislation.gov.uk, The National Archives."
}