Telescopic Lift
Telescopic handlers are versatile machines used primarily in the agricultural, construction and industrial sectors for material handling. Equipped with a telescopic boom that can extend in height and depth, these vehicles are designed to lift heavy loads in confined spaces where conventional machines might have difficulty operating.
Continuous power transmission with a single motor
Telescopic handlers require high tractive force in order to move material while working. However, transfer speeds are up to 40 km/h, depending on the country.
This extreme ratio of torque and speed is not met by conventional hydraulic transmissions.
For example, in Fig. 1, find the comparison between the solution using axial piston motor technology and the solution using SAI motor technology.
To cover the full performance range with axial piston motors, it is necessary to use two motors to meet the maximum torque, and then exclude one of the two to achieve the maximum speed.
SAI offers variable displacement motors with ratios up to 10:1, enabling the continuous transformation of hydraulic power into mechanical power, from minimum to maximum speed, without the use of additional motors.
|
Power available |
100 |
[kW] |
Power available |
100 |
[kW] |
|
Max pull force |
90000 |
[N] |
Max pull force |
90000 |
[N] |
|
Max vehicle speed |
40 |
[km/h] |
Max vehicle speed |
40 |
[km/h] |
|
Rolling radius |
0,5 |
[m] |
Rolling radius |
0,5 |
[m] |
|
Total gearbox ratio |
20 |
i |
Total gearbox ratio |
10 |
i |
|
Availabel flow @ max pressure |
150,0 |
[l/min] |
Availabel flow @ max pressure |
150,0 |
[l/min] |
|
Delta pressure |
400 |
[bar] |
Delta pressure |
400 |
[bar] |
|
Motor th. Displacement max |
90 |
[cc/rev] |
Motor th. Displacement max |
700 |
[cc/rev] |
|
Motor th. Displacement min |
35 |
[cc/rev] |
Motor th. Displacement min |
70 |
[cc/rev] |
|
No. of hyd motors in max pull force |
2 |
|
No. of hyd motors in max pull force |
1 |
|
|
No. of hyd motors in max speed |
1 |
|
No. of hyd motors in max speed |
1 |
|
Optimization of weights and dimensions
The SAI solution allows optimization of the transmission’s weight and footprint, as highlighted in Fig. 2, where the SAI engine, shown in green, is superimposed on the configuration with two axial piston engines. This weight reduction contributes not only to improved overall vehicle performance, but also to fuel efficiency, allowing telescopic handlers to operate more sustainably and with lower operating costs.
Improved efficiency for sustainable mobility
SAI’s radial piston engine offers maximum starting torque due to its crankshaft and swing cylinder design. In addition, the change in displacement in the SAI engine is made by changing the eccentricity of the shaft, thus the piston stroke. The contact angle between piston and shaft remains the same as the displacement changes
In contrast, axial piston engines upon displacement reduction change the angle of force application of the pistons, penalizing the resultant that contributes to torque generation, instead increasing the load on the bearings, reducing overall efficiency.
The design of the SAI engine allows it to maintain high efficiencies even as the displacement decreases.
This feature makes the engine the ideal SAI motor in vehicle electrification projects, decreasing hydraulic consumption and extending battery range.
Noise reduction
The SAI engine delivers power at a speed more suitable for machine use, generally requiring one or two fewer reduction stages than an axial piston engine.
This reduction in rotational speed leads to a decrease in noise frequency, contributing to a reduction in noise. This results in significant benefits for the operator and the surrounding environment, improving working conditions and reducing noise impact during operations
Key Points
- Continuous speed variation with a single motor, without the need for mechanical gearboxes.
- Decreased weight encumbrance.
- Increased transmission efficiency and quietness.
