We know not only the vehicle only linearly in the exercise of the exercise, as well as various angles of the curve, when the vehicle is traveling in a curve, the trajectory of the four wheels are four different radius of the arc. This has resulted in four different wheel speed in the bend, if only the wheels to rotate at the same speed that the vehicle can not turn, even if forced steering wheel rotation speed difference and also because of broken middle axle. Then you need to install the differential to achieve a differential, to a fixed speed output shaft of the engine into different rotational speed transmitted to the wheels. Usually only one of two differential drive, is mounted intermediate the front or rear axle.
1 central limited slip differential noun
when the vehicle is turning, the front wheel turning radius is larger than the rear of the same side, so the front wheel speed faster than the rear wheels , as well as four wheels take completely different routes, so that the need for a central four-wheel limited slip differential torque to front and rear axles assigned.
2 central limited slip differential classification
● multiple disc clutch differentials
● Torsen differential
● viscous coupling differential
● multiple disc clutch differentials
3. the multiple disc clutch differentials Detailed
multi-disc clutch differential works
multi-disc clutch differentials depend on wet multi-plate clutch are differential torque. This system is often used as a center differential timely four-wheel drive system use. There are two sets of friction disks therein, a set of driving disc, a driven plate group. Driving disc connected to the front axle, the rear axle is connected with the driven disc. Two dedicated disk is immersed in the oil, and a combination of both separation systems rely on electronic control.
In the straight running, the front and rear axles at the same speed, there is no difference in rotational speed between the driving disk and the driven disk, the disk case separation, precursor or substantially in the vehicle rear drive state, can achieve the purpose of saving fuel . In turning overProcess, the front and rear shaft rotational speed difference occurs, the rotational speed difference is generated also between the driving and driven discs. However, due to the speed difference does not reach the predetermined electronic system requirements, and thus sets the disk is still in the disengaged state, the steering of the vehicle is not affected at this time.
difference in the current rotational speed of the rear axle exceeds a certain limit, for example, the front wheels begin to slip, the electric control system controls the hydraulic multi-plate clutch pressing mechanism, when the driving disk and the driven disk contact starts to occur, similar to the clutch the combined torque is transmitted from the drive plate to the driven plate in order to achieve four-wheel drive.
on condition and the torque distribution ratio of the multi-plate friction type limited slip differential is controlled by an electronic system, fast response, some models further includes a manually controlled “LOCK” function, i.e. the primary driven plate piece combination can maintain full-time status, four-wheel drive lock function close to the state of professional off-road vehicles. However, the friction plate 50 can pass up to the percentage of torque to the rear wheels, and the use of high strength friction will overheat and fail.
Advantages: fast response speed, can instantly binding; binding most models are electrically controlled, without manual intervention;
drawbacks: a maximum of 50 percent power to the rear wheel, high load work is easy to overheat. The origin of
4. Detailed Torsen differential
works Torsen differential
Thorsen (Torsen) the name torque-sensing Traction– feeling take traction torque, the core Torsen worm, a worm gear system, from a structural view of the Torsen differentialTo see the double worm, the worm structure, it is their mutual engagement configuration, and the torque interlock unidirectionally transmitted from the worm wheel to the worm gear of the differential locking function is realized, this feature limits the slide. During normal driving in a curve, the role of the former, the rear differential is a conventional differential, a worm gear does not affect the output speed of the axle different, such as when the vehicle turn to the left and right wheel differential speed ratio, and left low speed, different speeds of the left and right can be closely match the synchronization worm gear. At this time, the worm and not locked, since the torque from the worm to the worm gear. When one side of the wheel slip, the worm components play a role, through a Torsen differential or hydraulic multi-plate clutch, very quickly and automatically adjusting power distribution.
When the normal driving of the vehicle when the differential case rotates P, while driving rotation of the worm 3 and 4, there is no relative rotation between the case 3 and 4, then the red and green of the shaft axis 2 the same rotation speed. When one side of the axle encounter greater resistance to the other side of the axle when idle, for example, red axle encounter greater resistance, then start its stationary, and the differential case is still rotating, thus driving the worm 4 along the axis of the rolling gear red, 4 while drive roll 3 is rotated, but the self-locking effect with the 3 green axles 2, 3 and so can not drive the rotation of the second rotation axle green, then 3 stops rotating, such that while 4 is also stopped, thus only the rotation of the differential case 4 of the axle rotation driven by the red, red soon distributes torque to the axle, the rescue vehicle.
is the central core of the torque-sensing device of the self-locking differential, it can make the power output according to a running state between front and rear axles to 25: 75 to 75: 25 is continuously changed, but the reaction is very fast, almost no hysteresis (torque-sensing differential of self-locking characteristics in the front are also analyzed in detail), and the support of an electronic stability program, and further improve the initiative of the power distribution.
Briefly, a fully automated Torsen differential is purely mechanical differential, i.e. the control does not require human +100 + percentage reliable direct transmission limited slip differential, from a certain angle He said to be a very balanced design.
Advantages: the moment of resistance can be provided a difference occurs between the drive wheels the feedback, the output torque distribution, and the lockup characteristic is linear, can be adjusted within a relatively wide range of output torque; [123 ]
drawbacks: No two drive state; limited slip differential limited capacity, the power has not fully transmitted to a wheel.
5. Detailed viscous coupling differentials
differential viscous coupling, a differential of this structure is today all-wheel drive automatic distributing power car smart device. It is usually mounted on the wheel drive based all-wheel-drive vehicle. The car with the usual manner by the front-wheel drive. The maximum viscosity characteristic without a driver coupling is operated, the power can be automatically assigned to the rear axle as desired.
works
of the viscous coupling, somewhat similar to the multi-plate clutch. The input shaft is equipped with a number of inner plates, many plates are inserted into the outer housing among the output shaft, and filled with a high viscosity silicone oil. The transmission input shaft and the front of the engine is connected to transfer means, connected to the output drive shaft and the rear axle.
during normal driving, there is no rotational speed difference between front and rear wheels, the viscous coupling does not work without the power to the rear wheels, a front-wheel drive car is still equivalent car.
to
on a snowy road cars, wheel slippage occurs, a larger front-rear wheel speed difference. Within the viscous coupling, the silicone oil between the outer plate is agitated start thermal expansion, have a great viscosity resistance, to prevent relative movement between the inner and outer panels, resulting in a large torque. In this way, the power is automatically transferred to the rear wheels, the car into a fully-wheel drive car.
when the vehicle is turning, the viscous coupling may also absorb rotation speed difference due to the inner wheel difference between the front and rear wheels is generated, before and after differential functions. When the car brakes, it can prevent the rear wheels to holdDead phenomenon.
Advantages: compact size, simple structure, low production cost;
Disadvantages: The disadvantage is slow response, low torque distribution ratio, binding and separation can not be manually controlled, high load work overheat It may fail.