Compact, efficient, cost-effective: Hoerbiger will showcase its new CompactLINE synchronizer on June 18 and 19, 2013 at the International VDI Congress "Transmissions in Vehicles" in Friedrichshafen, Germany. The synchronizer was developed for manual and dual-clutch transmissions used in the high-volume compact and mid-range car segments and operates based on a unique functional principle. OEMs and transmission manufacturers will benefit from CompactLINE's significant weight and size reduction with best-in-class shifting comfort.

More than 80 years ago, BorgWarner revolutionized the shifting comfort of transmissions with a device that allowed gear shifts without throttle blipping and double clutching - the transmission synchronizer was born. Apart from some detail improvements, almost all series-produced synchronizer systems have operated based on this original principle ever since.

During times where automobile producers and transmission manufacturers scrutinize every single component in the quest for optimization potential, this functional principle is reaching its limits. To be able to transmit the necessary torque and offer adequate shifting comfort, a particular minimum size must be met. This reduces the options for downsized transmissions, especially when it comes to the price-sensitive high-volume transmissions used in compact and mid-sized cars, and stands in the way of potential weight and cost savings in transmission construction.

Metal forming know-how paves the way
With this in mind, Hoerbiger has reconsidered an alternative synchronization principle, the outer cone synchronizer. This concept has been around since the 1970s, yet previously only few manufacturers dared to consider series production of the required components. Complicated contours necessitate complex machining steps, resulting in a cost-intensive and uneconomical production process.

This has changed fundamentally with the CompactLINE: HOERBIGER has been manufacturing synchronizer rings using only metal forming technology since 1996. The Strategic Business Unit Drive Technology has now applied the know-how gathered in the past decade and a half to the overall synchronizer system. The CompactLINE has made an outer cone synchronizer available that is not only compact and efficient, but also competitive to produce. Hoerbiger uses almost 100 percent of metal-formed parts for the CompactLINE.

Compact powerhouse for small transmissions
Compared to standard synchronizers, the outer friction cone of the CompactLINE provides up to a 20 percent increase in friction torque. In practice, this means best-in-class shifting comfort while maintaining a high level of comfort in a considerably reduced installation space. The CompactLINE rounds out the Hoerbiger synchronizer portfolio for small transmissions with up to 200 Nm input torque. Combined with the Hoerbiger sintered linings, even maximum loads are not a problem, while keeping wear low.

The CompactLINE achieves weight savings in two respects: not only is the synchronizer itself up to 35 percent lighter than standard products, but its compact design also allows a smaller complete transmission system. As a result, the transmission housing and the necessary oil quantities shrink along with the CompactLINE. The elimination of the solid sliding sleeve and active lifting of the synchronizer rings assure moment of inertia that is approximately 25 percent lower as well as reduced drag loss. This significantly increases transmission efficiency.

Efficient solution for the downsized drive train
The design of the Hoerbiger CompactLINE assures that all the components are guided in the prescribed manner and prevents NVH problems due to vibrations from loose parts. This is an important acceptance criterion for customers - especially in connection with the rather rough-running downsized three- or two-cylinder engines.

The advantages of the CompactLINE benefit not only classic manual transmissions. Even modern double-clutch transmissions couldn't shift gears without synchronizers. An additional interesting field of application includes automated manual transmissions (AMTs). Gears are changed automatically in AMTs, and the clutch is also operated by an actuator; there is no clutch pedal.

This makes AMTs a cost-effective alternative to dual-clutch and torque-converter transmissions and they are increasingly gaining in popularity, notably in the emerging markets. The drawback is that the automatic gear change is usually not as responsive as that of an experienced driver. The friction torque of the CompactLINE, which is the highest in its class, assures minimized synchronization times. As a result, shifting through gears can be done more quickly and the clutch need not remain disengaged as long. This lowers the effect of interruption of torque flow, which has been the object of frequent criticism in AMTs.