Reverse gear
In Germany, according to Section 39 of the Road Traffic Licensing Regulations , certain types of motor vehicle must be able to be reversed from the driver's seat.
A reverse gear (implemented in the transmission) is not mandatory for this purpose, but is necessary in vehicles with a pure internal combustion engine as the drive.
Even vehicles that do not fall under this regulation are partially equipped with reverse gear, e.g. B. heavy motorcycles .
As early as 1895, Daimler offered the so-called belt car with reverse gear. Benz followed in 1896, and the Velociped was now also available with reverse gear at the customer's request. From 1900, reverse gear was standard at Benz.
In technical terms, the
- Change- speed gearbox (gearbox) between the main shaft and countershaft a reverse gear interposed and at
- Automatic transmission z. B. held the planet carrier of a simple planetary gear set, thereby changing the direction of rotation of the drive shaft. Some automatic transmissions also have two reverse gears. The second gear is then used to simplify moving off on a slippery road surface.
The Toyota Prius does not have its own reverse gear in the transmission. Instead, the motor generator 2 (which is rigidly coupled to the drive wheels) is driven backwards. The Prius always drives backwards electrically, while the combustion engine is at a standstill, unless it is running at idle speed to warm up or charge the battery.
Even in purely electrically operated vehicles, there is no reverse gear, the reverse direction of rotation of the electric motor enables reversing in such vehicles.
In older French automobiles, reverse gear is usually marked with "AR" instead of "R", because reverse means arrière in French .
The reverse gear usually has a reduction ratio roughly like the 1st (slowest) forward gear. If a vehicle has one or two further transmissions, for example fine gradation (s) (back gear) for trucks or an off-road reduction that affects all gears, there may be several "ratios" available for reversing. The driving noise in reverse gear often differs greatly from that when driving forward and is louder because straight-toothed gears are often used instead of helical-toothed gears . For reasons of cost, a disadvantageous acoustic behavior is tolerated when reversing. Work machines sometimes have the same number of reverse and forward gears. In the case of caterpillars or wheel loaders, for example, they can even be reduced more quickly (than forwards), since the shovel or shield then demand no or less pushing force.
literature
- Hans Jörg Leyhausen: The master craftsman's examination in the automotive trade. Part 1. 12th edition. Vogel Buchverlag, Würzburg 1991, ISBN 3-8023-0857-3 .
- Max Bohner, Richard Fischer, Rolf Gscheidle: Expertise in automotive technology. 27th edition. Verlag Europa-Lehrmittel, Haan-Gruiten 2001, ISBN 3-8085-2067-1 .
