Haldex Traction
The Haldex coupling is an electronically controlled multi-plate clutch, which was developed by the Swedish automotive supplier Haldex. It is manufactured and marketed since 2011 by Borg Warner. It is used in cars to build a four-wheel drive.
Operation
The close- axis is permanently driven. The all-wheel drive, based on a Haldex clutch automatically passes, without the driver, engine power as needed to the other axis. Depends on the locking effect of the electronically controlled Haldex coupling a variable proportion of the engine power is transmitted to this axis, if necessary.
For example, by rotating a drive wheel, as the annular piston pump is actuated by the cam disc and generates a liquid pressure. This acts on the working piston which pushes the outer and inner toothed disks against each other. At full power circuit in the disk set input and output shaft are (and front and rear axle drive ) rotatably connected to each other. The speed compensation is locked and the torque is allocated to the driving wheels according to their traction. The pressing force of the plate pack and therefore of the locking value is controlled electronically by the control device via the control valves.
The electronic control unit, a four-wheel drive based on the Haldex clutch is fully compatible with driver assistance systems such as ABS and ESP. If necessary, a final drive can be turned off within 60 ms.
Construction
The Haldex coupling is directly flanged to the housing of the final drive and acts as a center differential lock.
The clutch locks the speed balance between the front and rear axle drive traction dependent and distributed the coming of the gearbox torque to the axle gear. The Haldex coupling consists of the housed in a sealed enclosure disc set, two parallel annular piston pumps, piston, cam disk, control valve, safety valve, stepper motor and control unit. The externally toothed disks are rotatably connected to the input shaft ( propeller shaft ), the internally toothed blades to the output shaft ( the axle drive bevel gear ). The annular piston pumps are driven at speed differences between the input and output shaft through the cam.
Versions
There are several generations of Haldex clutches ( 1-5, Booth 2013, see Related links ). The locking value of the Haldex clutches generation 1-3 is mainly controlled by the difference in speed of the driven axles with the objective of maximizing traction.
Generation 4 features an electric oil pump with accumulator and can be used to enhance driving dynamics, eg to stabilize the vehicle even without wheel slip before unwanted situations occur. Features such as a locking of the Haldex clutch in the vehicle stand in support of the traction at the starting acceleration are possible with the fourth generation.
Generation 5 features a lightweight and compact design that reduces the vehicle complexity and simplifies integration into the powertrain. With the aid of an electro- hydraulic pressure control valve, the centrifugal force is automatically distributed between the front and rear wheels. This eliminates the accumulator, solenoid valves and filters. An integrated electronic control unit calculates the data and provides a preventive, immediate response with high torque accuracy. When the four-wheel drive is not required, allows the uncoupling of the clutch release entire secondary driveline. Haldex clutches of the fifth generation are, for example, the Volkswagen Golf VII 4Motion used.
Use
Haldex clutch - controlled four-wheel drives are located in the following car models (excerpt from ):
- Audi A3 and TT - " quattro " models, S3, TTS, TTRS
- Bugatti Veyron
- Ford Kuga
- Opel Insignia
- Volvo V40 Cross Country, Volvo S60, Volvo V60, Volvo XC60, Volvo V70, Volvo XC70, Volvo S80, Volvo XC90
- VW Golf, Passat, Sharan, Caddy, Tiguan, Transporter T5 - " 4MOTION " models
- Seat Alhambra, Altea XL Freetrack, Leon
- Škoda Yeti, Octavia II, Superb II
- Saab 9-3 XWD; Saab 9 -3X; Saab 9-5 XWD
- Lamborghini Aventador