Recently, cars with automatic transmissions have begun to be in great demand . And no matter how many motorists say that automatic transmission is an unreliable mechanism that is expensive to maintain, statistics state the opposite. Every year there are fewer cars with manual transmission. The convenience of the “machine” was appreciated by many drivers. As for expensive maintenance, the most important part in this box is the automatic transmission torque converter. A photo of the mechanism and its structure are further in our article.
Characteristic
In addition to this element, the design of an automatic transmission includes many other systems and mechanisms. But the main function (this is torque transmission) is performed by the automatic transmission torque converter. In common parlance, it is called a “bagel” due to the characteristic shape of the structure.
It should be noted that on
automatic transmissions for front-wheel drive cars, the automatic transmission torque converter includes a differential and a final drive. In addition to the torque transfer function, the “donut” takes on all vibrations and shocks from the engine flywheel, thereby smoothing them to a minimum.
Design
Let's look at how the automatic transmission torque converter is arranged. This element consists of several nodes:
- Turbine wheel.
- Lock-up clutch.
- Pump.
- Reactor wheel.
- Freewheels.
All these mechanisms are placed in a single case. The pump is directly connected to the engine crankshaft. The turbine mates with the gears of the gearbox. The reactor wheel is located between the pump and the turbine. Also in the design of the bagel wheel there are blades of a special shape. The operation of the automatic transmission torque converter is based on the movement of a special fluid inside (transmission oil). Therefore, the automatic transmission also includes oil channels. In addition, there is a radiator. Why is it needed, we will consider a little later.
As for the couplings, the interlock is designed to fix the position of the torque converter in a certain mode (for example, "parking"). The freewheel is used to rotate the reactor wheel in the back.
Automatic Transmission Torque
How does this item work in a box? All actions of the "donut" are carried out in a closed cycle. So, the main working fluid here is the "transmission". It is worth noting that it differs in viscosity and composition from those used in mechanical boxes. During the operation of the torque converter, lubricant flows from the pump to the turbine wheel, and then to the reactor wheel.
Thanks to the blades, the liquid begins to rotate faster inside the "donut", thereby increasing the torque. When the crankshaft rotational speed increases, the angular speed of the turbine and pump wheel is leveled. The fluid flow changes direction. When the car has already gained sufficient speed, the “donut” will work only in the fluid coupling mode, that is, transmit only torque. When the speed increases, the GTF is blocked. In this case, the clutch closes, and the moment is transferred from the flywheel to the box directly, with the same frequency. The element is disconnected again when shifting to the next gear. Thus, the angular velocities are smoothed again until the turbine rotation speed is equal.
Radiator
Now about the radiator. Why is it displayed separately in automatic gearboxes, because such a system is not used on the “mechanics”? Everything is very simple. On a mechanical box, oil has only a lubricating function.
At the same time, it is only half filled. The fluid is contained in the drip tray and the gears are wetted. In an automatic box, oil performs the function of transmitting torque (where the name “wet clutch” comes from). There are no friction discs - all the energy goes through turbines and oil. The latter is constantly moving in the channels under high pressure. Accordingly, the oil must be cooled. For this, a heat exchanger is provided in such a transmission.
Malfunctions
The following transmission breakdowns are distinguished:
- GTF malfunction.
- Damage to the brake band and friction clutches.
- Malfunction of the oil pump and monitoring sensors.
How to identify a breakdown?
It is quite difficult to find out exactly which element failed, without dismantling the box and disassembling it. However, serious repairs can be predicted for several reasons. So, if there are malfunctions in the automatic transmission torque converter or brake band, the box will “kick” when switching modes. The machine starts to twitch if you put the handle from one mode to another (and when the foot is on the brake pedal). Also, the box itself enters emergency mode. The car only moves in three gears. This suggests that the box needs serious diagnostics.
As for the replacement of the torque converter, it is carried out with the complete dismantling of the box (drive shafts, “bell” and other parts are disconnected). This element is the most expensive component of any automatic transmission. The price of a new gas turbine engine starts at $ 600 for budget car models. Therefore, it is important to know how to use the box in order to delay repair as much as possible.
How to save the checkpoint?
It is believed that the resource of this transmission is an order of magnitude lower than that of mechanics. However, experts note that with proper maintenance of the unit, you will not need to repair or replace the automatic transmission torque converter. So, the first recommendation is a timely oil change. Regulation - 60 thousand kilometers. And if the manual transmission oil is filled for the entire period of operation, then in the "machine" it is a working fluid. If the grease is black or has a burning smell, it must be replaced immediately.
The second recommendation is on temperature conditions. It is not necessary to start the movement too early - the temperature of the box oil should be at least 40 degrees. To do this, move the lever in all modes with a delay of 5-10 seconds. So you warm up the box and prepare it for use. It is undesirable to drive in cold oil, as well as in very hot. In the latter case, the liquid will literally burn (when replacing, you will hear the smell of burning). Automatic transmission is not suitable for drift and tough operation. Also, do not turn on the neutral gear on the go, and then turn on the “drive” again. This will break the brake band and a number of other important elements in the box.
Conclusion
So, we found out what the automatic transmission torque converter is. As you can see, this is a very important unit in the box. It is through it that the torque is transmitted to the box, and then to the wheels. And since the oil here is a working fluid, you must follow the rules for its replacement. So the box will delight you with a long resource and smooth switching.