China's largest domestic sales capacity of 3 t, 5 t wheel loader, Wheel Loader the use of rated speed 2 200 r / min engine, and foreign type of loader commonly used rated speed of 1 800 r / min, 2 000 r / Min or 2 100 r / min of the engine. Selection of low-speed engine has the following four advantages: First, can reduce the engine vibration and noise, the second is to slow down the engine parts wear and tear, Wheel Loader the third is to improve the engine start and accelerate performance, four is to reduce energy consumption 8% 15%.
In recent years, the domestic main loader manufacturer has part of the 3 t, 5 t loader equipped with rated speed of 1 900 r / min (or 2 000 r / min) of the engine. Wheel Loader Such as the Dragon workers D series LG855D, ZL50CD loader rated speed 1 900 r / min engine, Liugong CLG855N, temporary labor LG953N and other new 5 t loader with rated speed 2 000 r / min engine, have access to Better energy efficiency and user acceptance.
After the engine rated speed is reduced, its matching condition with the torque converter also changes, so the external characteristic parameters of the torque converter must be adjusted. Wheel Loader The adjustment of the torque converter includes the following aspects: First, the appropriate increase in capacity (ie, nominal torque Mbg), to ensure full power matching conditions; Second, adjust the torque converter maximum torque than the K0 value (other points K value corresponding Adjust) to ensure maximum traction; Wheel Loader third is to reduce the high speed gear ratio to meet the maximum speed required. This is because 2 into a retrograde box to achieve down two gear ratio is not easy, generally not used.
But the use of low-speed engine there is a certain risk. Such as the use of twin-wheel hydraulic torque converter +2 into a retrograde 5 t loader, equipped with down-speed engine, Wheel Loader the torque converter turbine maximum output torque increased by about 8% to 10%. This is detrimental to the reliability of the transmission's two-axis assembly (ie, overrunning clutch).
The torque converter guide wheel is equipped with one-way clutch (free wheel), which is already standard in the forklift torque converter, but has not been used in the domestic wheel loader hydraulic torque converter. Wheel Loader In the light load conditions, the one-way clutch can make the torque converter to achieve coupling conditions (coupler), transmission efficiency as high as 94% to 97%.
The loader requires a one-way clutch to lock the force during the shovel operation, while the light load condition requires a one-way clutch disengagement to achieve efficient coupling conditions. Wheel Loader In the torque converter equipped with one-way clutch (free wheel) can make the loader to obtain better energy saving effect. Wheel Loader If the CAT 950H wheel loader torque converter is equipped with a one-way clutch.
When the lock-up clutch is locked, the loader can be switched from the hydraulic-mechanical drive to the mechanical drive, so that the torque converter's transmission efficiency η ≈ 1 (ignoring the friction of the torque converter). When the torque converter is equipped with a lock-up clutch, Wheel Loader it is also necessary to set the one-way clutch in the guide wheel. When the lock-up clutch is locked (mechanical drive), the one-way clutch is disengaged so that the guide wheel is free to rotate and no excessive energy loss occurs.
One-way clutch (free wheel) is automatically completed conversion, and the locking clutch combination and separation requires human intervention, the control is as follows: work block (1 block), Wheel Loader the torque converter is not locked to meet the complex heavy Operating conditions; transport block (2,3,4 block), the torque converter lock to improve the transmission efficiency, to achieve energy saving effect;Wheel Loader shift operation, the torque converter is not locked to reduce the impact of the shift The
"One-way free wheel + lock-up clutch" is the most effective way to improve the efficiency of domestic wheel loader transmission system, should be vigorously developed. Wheel Loader Such as Volvo L150, L180, L220 and other wheel loader torque converter has been equipped with one-way clutch and lock-up clutch.