Modeling of the Rotary Mechanism of the Hydraulic Manipulator of a Timber Truck

Abstract

The importance of loading and unloading operations in the technological process of wood hauling by timber trucks, as well as the need to improve the design of hydraulic manipulators, are considered. The most rational ways to increase the efficiency of their functioning are given. The disadvantages of traditional designs of hydraulic manipulator rotary mechanisms based on rack-and-pinion gears are presented. An improved design of the crank rotary mechanism of the hydraulic manipulator column from six hydraulic cylinders is proposed. The research methodology is based on the use of mathematical modeling. It has been revealed that the accumulated energy for one braking cycle when moving the load is about 1442 J. Considering that timber loading is carried out at a height of approximately 2 m, the recovery system allows approximately 12 % of the rotation energy to be directed to the load lifting operation. Over the entire range of change in the angle of the end of rotation, the recovered energy varies by only 7.1 % – from 1340 to 1442 J, and the load swing amplitude – by 1.2 % – from 0.336 to 0.340 m. It has been determined that with an increase in the length of the guide, the recovered energy decreases slightly – from 1564 to 1428 J (by 8.7 %) – and the load swing amplitude – from 0.344 to 0.339 (by 1.5 %). It has been found that over the entire angular range, the recovered energy varies from 1399 to 1442 J (by 3 %), and the load swing amplitude – from 0.3380 to 0.3393 m (by 0.4 %). The angular unevenness of the recovery efficiency indicators is no more than 3 %. To study the influence of the parameters of the crank rotary mechanism of the hydraulic manipulator column on the efficiency of energy recovery, a multifactor optimization problem has been solved. It has been established that the optimal value of the distance from the crank axis to the movable axes of the hydraulic cylinders of the rotary mechanism of the hydraulic manipulator column is 0.23–0.25 m, the optimal value of the displacement of the crank axis relative to the axis of the manipulator column is 0.17–0.18 m. At the same time, the recovered energy for 1 cycle of load moving is at least 1500 J, and the amplitude of the load swing is no more than 0.35 m.

Keywords

• column crank rotary mechanism
• timber truck
• hydraulic manipulator
• hydraulic cylinders
• energy recovery
• timber
• handling operations
• performance indicators
• hydropneumatic accumulator