Development of “Low Torque Seal Ring” for Automotive Transmissions
[World first! Formation of proprietary V-shaped lubrication groove to reduce rotational torque by 60%, contributing to greater efficiency!]
NTN Corporation (hereafter, NTN) has developed seal rings for automotive transmissions that deliver low torque, low wear and fewer oil leaks by optimizing the plastic composite material composition, as well as incorporating a specially-shaped lubrication groove on the surface of the seal rings.
Automatic Transmissions (AT) and Continuously Variable Transmissions (CVT) use four to 10 plastic seal rings with an outer diameter of 15 to 60 mm. Seal rings are installed between the shaft and housing that move in relative motion within the oil hydraulic circuits of transmissions, and slide together so that oil remains sealed in. With fuel efficiency standards becoming ever more stringent, there is demand for even lower torque and fewer oil leaks, as well as greater reliability of seal rings used in gearboxes.
The newly developed “Low-torque Seal Ring” use a PEEK (polyether ether ketone) plastic featuring a special filler, and incorporate a V-shaped lubrication groove formed on the surface of the seal rings during injection molding. This V-shaped groove has been given an optimal design that reduces the contact area between the shaft groove surfaces incorporated with the seal rings, while maintaining its oil leak characteristics. Improvements have also been made to the oil feed performance on the sliding surface to increase lubrication conditions. These developments have led to a 60% reduction in shaft rotation torque compared to conventional products, as well as improve the amount of wear by up to 1/10. Additionally, the material composition has been revised to reduce the width of the seal ring by 30%. Use of these seal rings contributes to greater efficiency and more compact AT and CVT.
Formation of the V-shaped lubrication groove is a proprietary NTN technology, and is the first of its kind in the world.
NTN has already started proposing the developed product to automotive transmission manufacturers as a solution that contributes to greater energy efficiency, with application to be expanded to transmissions for agricultural machinery and construction machinery.
[ Features ]
| Compared to conventional products (compared to rectangular cross-section shape) |
| (1) |
Torque |
: |
60% reduction |
| (2) |
Amount of wear |
: |
up to 1/10 |
| (3) |
Oil leak characteristics |
: |
equivalent |
| (4) |
Seal ring width |
: |
30% reduction |
[ Inquiries about this release ]
[ Product photo ]
[ Example of applications ]
Example of use in Automatic Transmissions (AT)
