ZF 6HP transmission
World's first 6-speed automatic from 2000
From Wikipedia, the free encyclopedia
6HP is ZF Friedrichshafen AG's trademark name for its 6-speed automatic transmission models (6-speed transmission with Hydraulic converter and Planetary gearsets) for longitudinal engine applications, designed and built by ZF's subsidiary in Saarbrücken.
| 6HP | |
|---|---|
Automatic Transmission 6HP 26 cutaway | |
| Overview | |
| Manufacturer | ZF Friedrichshafen |
| Production | 2000–2014 |
| Model years | 2000–2014 |
| Body and chassis | |
| Class | 6-Speed longitudinal automatic transmission |
| Related | Lepelletier planetary gearset Ford 6R GM 6L Aisin AWTF-80 SC MB 7G-Tronic |
| Dimensions | |
| Curb weight | 72–99 kg (159–218 lb)[1] |
| Chronology | |
| Predecessor | ZF 5HP |
| Successor | ZF 8HP |
It uses the Lepelletier planetary gearset,[2] an epicyclic gearset, which can provide more gear ratios with significantly fewer components. This means the 6HP 26 is actually lighter than its five-speed 5HP predecessors. The 6HP is the first transmission to use the Lepelletier planetary gearset.
The Ford 6R, GM 6L and Aisin AWTF-80 SC transmissions are all based on the same globally patented Lepelletier planetary gearset. The AWTF-80 SC is the only one for transverse engine installation.
Key data
| Model | First Deliv- ery |
Gear | Total Span | Avg. Step |
Components | Nomenclature | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| R | 1 | 2 | 3 | 4 | 5 | 6 | Nomi- nal |
Effec- tive |
Cen- ter |
Total | per Gear[b] |
Gears Count |
Cou- pling |
Gear- sets |
Input Shaft Diameter | |||
| 2000: 1st generation | 3 Gearsets 2 Brakes 3 Clutches |
1.333 | 6[b] | H[c] | P[d] | 2000 | ||||||||||||
| 6HP 26[e] · 6HP 19 · 6HP 32 | −3.403 | 4.171 | 2.340 | 1.521 | 1.143 | 0.867 | 0.691 | 6.035 | 4.924 | 1.698 | 1.433 | 26 mm · 19 mm · 32 mm | ||||||
| 2007: 2nd generation | 2007 | |||||||||||||||||
| 6HP 28 · 6HP 21 · 6HP 34 | −3.403 | 4.171 | 2.340 | 1.521 | 1.143 | 0.867 | 0.691 | 6.035 | 4.924 | 1.698 | 1.433 | 28 mm · 21 mm · 34 mm | ||||||
| Other manufacturer using the Lepelletier planetary gearset | Installation | Maximum Input Torque | ||||||||||||||||
| Aisin AWTF-80 SC | 2005 | −3.394 | 4.148 | 2.370 | 1.556 | 1.155 | 0.859 | 0.686 | 6.049 | 4.949 | 1.687 | 1.433 | transverse | 450 N⋅m (332 lb⋅ft) | ||||
| Ford 6R 60 · 6R 80 | 2005 | −3.403 | 4.171 | 2.340 | 1.521 | 1.143 | 0.867 | 0.691 | 6.035 | 4.924 | 1.698 | 1.433 | R[f] | 600 N⋅m (443 lb⋅ft) · 800 N⋅m (590 lb⋅ft) | ||||
| Ford 6R 140 | 2005 | −3.128 | 3.974 | 2.318 | 1.516 | 1.149 | 0.858 | 0.674 | 5.899 | 4.644 | 1.636 | 1.426 | 1,400 N⋅m (1,033 lb⋅ft) | |||||
| GM 6L 45 · 6L 50 | 2006 | −3.200 | 4.065 | 2.371 | 1.551 | 1.157 | 0.853 | 0.674 | 6.035 | 4.751 | 1.655 | 1.433 | L[g] | 500 N⋅m (369 lb⋅ft) | ||||
| GM 6L 80 · 6L 90 | 2005 | −3.064 | 4.027 | 2.364 | 1.532 | 1.152 | 0.852 | 0.667 | 6.040 | 4.596 | 1.638 | 1.433 | 800 N⋅m (590 lb⋅ft) · 1,200 N⋅m (885 lb⋅ft) | |||||
| ||||||||||||||||||
History
Released as the 6HP 26 in 2000, it was the first 6-speed automatic transmission in a production passenger car. Other variations of the first generation 6HP in addition to the 6HP 26, were 6HP19, and 6HP 32 having lower and higher torque capacity, respectively. In 2007, the second generation of the 6HP series was introduced, with models 6HP 21 and 6HP 28. A 6HP 34 was planned, but never went into production.[3] The last 6HP automatic transmission was produced by the Saarbrücken plant in March 2014 after 7,050,232 units were produced.[4][5] The ZF plant in Shanghai continued to produce the 6HP for the Chinese market.[4]
Planetary gearset concept
Improved fuel economy
The main objective in replacing the predecessor model was to improve vehicle fuel economy with extra speeds and a wider gear span to allow the engine speed level to be lowered (downspeeding), which is a decisive factor in improving energy efficiency and thus reducing fuel consumption. In addition, the lower engine speed level improves the noise-vibration-harshness comfort and the exterior noise is reduced. It has a torque converter lock-up for all 6 forward gears, which can be fully disengage when stationary, largely closing the fuel efficiency gap between vehicles with automatic and manual transmissions.
Reduced manufacturing complexity
In order to avoid a further increase in manufacturing complexity while expanding the number of gear ratios, ZF switched from the conventional design method—in which the planetary gearset concept was limited to a purely serial or in-line power flow—to a more modern design method that utilizes a planetary gearset concept with combined parallel and serial power flow. This was only possible thanks to computer-aided design and has resulted in a globally patented gearset concept. The resulting progress is reflected in a better ratio of the number of gears to the number of components used compared to existing layouts. The 8HP has become the new reference standard (benchmark) for automatic transmissions.
Quality
The ratios of the 6 gears are evenly distributed in all versions. Exceptions are the large step from 1st to 2nd gear and the almost geometric steps from 3rd to 4th to 5th gear. They cannot be eliminated without affecting all other gears. As the large step is shifted due to the large span to a lower speed range than with conventional gearboxes, it is less significant. As the gear steps are smaller overall due to the additional gear(s), the geometric gear steps are still smaller than the corresponding gear steps of conventional gearboxes. Overall, therefore, the weaknesses are not overly significant. As the selected gearset concept saves up to 2 components compared to 5-speed transmissions, the advantages clearly outweigh the disadvantages.
The layout brings the ability to shift in a non-sequential manner – going from gear 6 to gear 2 in extreme situations simply by changing one shift element (actuating clutch E and releasing brake A).
In a Lepelletier planetary gearset,[2] a conventional planetary gearset and a composite Ravigneaux gearset are combined to reduce both the size and weight as well as the manufacturing costs. Like all transmissions realized with Lepelletier transmissions, the 6HP also dispenses with the use of the direct gear ratio and is thus one of the very few automatic transmission concepts without such a ratio.
Imperfections
Problems with this transmission are well known.[citation needed] This transmission locks up the torque converter in all gears, increasing wear. Combined with a sealed transmission pan and "lifetime fluid", some people have experienced catastrophic transmission failure. Owners report shift issues when oil begins breaking down beyond 50K miles, hence shifting issues are common.[citation needed]
There are also problems with the valve block and solenoids.[citation needed] When this failure starts to occur, shift quality and speed, torque transfer and even loss of ability to engage gears can occur. These problems led Volkswagen Group to extend the warranty on all of their vehicles equipped with this transmission to 100,000 miles or 10 years.[citation needed]
Applications
| Model | Car Model[a] |
|---|---|
| 2000: 1st generation | |
| 6HP 19 |
|
| 6HP 19A[b] |
|
| 6HP 26[c] |
|
| 6HP 26A[e] |
|
| 6HP 26X and 6HP 26Z[f] |
|
| 6HP 32 |
|
| 6HP 32A[h] |
|
| 2007: 2nd generation | |
| 6HP 21 |
|
| 6HP 28 |
|
| 6HP 34[i] | |
| |