Ardelt gear
The Ardelt gearbox was a compact, fully automatic gearbox, which was developed by the Ardelt works and was used, especially in crane construction, for the stepless control of different speed levels. It was also used in some automotive applications. Well-known representatives are the Ardelt locomotives and the T 4 railcar of the Niederbarnimer Eisenbahn (NEB T 4).
construction
The way the Ardelt gearbox worked was a step forward compared to conventional mechanical gears when it was first developed. Its mode of operation was based on a non-positive connection via several clutch plates , which were engaged and disconnected again with compressed air cylinders and were protected against incorrect movements with a freewheel .
The attached sketch shows the mode of operation of the overrunning clutch for one speed level. On the shaft a , the inner disk carrier b is placed on a section with a spline shaft . It has a sliding engagement disc c on its hub . The inner plate carrier with the lamellae e is also arranged on the plate carrier b . The outer plate carrier f carries the outer plates g and is designed as a nut in the hub. It sits on a screw thread h , which is firmly connected to the gear of a gear i . There is no power transmission in the sketch. But on the engaging disk c the lamellae of the inner disk carrier b against the plates of the outer disk carrier f pressed, via the force fit between the plates e and g , the torque of the drive via the thread h on the gear i transmitted. The screw thread h is provided with a multi-start flat thread . The outer plate carrier f is also supported by a spring against the gear wheel i , so that the frictional connection occurs immediately with the slightest displacement of the plates. The freewheel is located in the gear wheel i , which interrupts the power transmission when the car is traveling downhill. If the motor is to be braked, the freewheel can be blocked.
The gearbox was manufactured according to the standards of gearbox construction; the gears and shafts were made of chrome-nickel steel , the helical drive wheels were hardened and ground . The slats were made of high-quality special steel, they were hardened, ground and tempered . On the part of the description, the wear should have been almost zero.
Characteristic
The advantage of the gearbox was that, on the one hand, the main clutch could be saved and the frictional connection was distributed over four elements instead of one. On the other hand, there was no significant reduction in speed and no interruption of tractive power when shifting, so that the engine and transmission were constantly in a positive connection. In addition, all of the gear wheels to be shifted in the transmission stages were constantly in mesh.
The gearbox could be shifted either manually or automatically. For this, the vehicle had an order switch for the manual or automatic position . The reversing gear could also be reversed with this order switch. In the manual position , gear shifting was carried out in the same way as the driving switch position. When the drive switch was changed, a shift motor was electrically turned to the desired gear. The switching process was monitored with the contact tachometer , which monitored the actual state of the transmission. If the engine speed matched the data on the contact tachometer, a solenoid valve was activated and the relevant gears were pneumatically connected or lifted. This monitoring prevented incorrect shifting and shifting into another gear was not possible if the diesel engine speed did not correspond to the gear step. As a result, there was a desired level of safety, overload and excessive throttling of the engine.
With the fully automatic switching option, the engine driver had to set the control switch to position A. The gearbox was switched fully automatically depending on the speed and the engine load. The switching process for the four gears was determined by the contact tachometer, four solenoid valves then controlled the cylinders for controlling the gears in question according to the signals from this tachometer. All gear pairs of the mechanical transmission were constantly in mesh, the required gear was engaged via overrunning clutches controlled by these solenoid valves. During the switching process, the engine driver did not have to take any action during the switching process and was not distracted from monitoring the route. He didn't have to take his hand off the brake lever or the drive switch. The drive switch was designed as a dead man's device . The railcar could not start if it was not pressed; if it was released while it was moving, an emergency brake was initiated. The automatic switching brought about a significant time saving compared to manual switching.
The gearbox was arranged in the NBE T 3 according to the enclosed sketch. The railcar was powered by an engine with an output of 225 hp. This sat at the front end of the bogie and drove the rear axle via the Ardelt gearbox . The other axis was driven by a connecting rod. The NEB T 4 was powered by two engines of 150 hp each. The drive took place on the inner axle of the two bogies. The Niederbarnimer Eisenbahn had chosen a four-stage transmission for their railcars. The NBE T 3 was able to reach a speed of 60 km / h in 60 s and covered a distance of 600 m at this acceleration. This could not be achieved by any other railcar with mechanical power transmission and the same performance. Compared to vehicles of the same performance with diesel-electric drive , economic superiority has been demonstrated through weight and fuel savings.
In addition to the railcars of the Niederbarnimer Railway, shunting locomotives with this transmission are known. Today the differential converter transmission takes on the same task while saving the four gears and clutch plates.
See also
literature
- DW Matthes diesel multiple units with geared power transmission of the Niederbarnimer Eisenbahn in Verkehrstechnik issue 19, 1935
- Walter Kraetsch: New diesel-mechanical railcar from Niederbarnimer Eisenbahn AG . In Verkehrstechnik Heft 5, 1938, page 112 ff.
- RoR Boehme: A new non-positive transmission for internal combustion engines in KR Repetzki diesel locomotives in Glaser's Annalen 1895-1936, Transpress Reprint, Berlin 1987, ISBN 3-344-00127-2 , pages 186 ff.
Web links
Individual evidence
- ↑ a b c RoR Boehme: A new frictional transmission for internal combustion engines in KR Repetzki diesel locomotives in Glaser's Annalen 1895-1936, Transpress Reprint, Berlin 1987, ISBN 3-344-00127-2 , pages 186
- ↑ a b Walter Kraetsch: New diesel-mechanical railcar from Niederbarnimer Eisenbahn AG. In Verkehrstechnik Heft 5, 1938, page 116
- ^ DW Matthes diesel railcars with geared power transmission of the Niederbarnimer Eisenbahn in Verkehrstechnik issue 19, 1935