How do I calculate the speed of a ballscrew?
Roller Screws are structurally divided into two types: internal and external. The inner-circulation structure adopts circular or oval reversing device, which is compact and occupies little space, and is suitable for occasions requiring high installation size; the outer-circulation structure relies on the cannula device to realize ball circulation, and although the overall size is relatively large, it performs well in terms of load carrying capacity and impact resistance. There is no absolute advantage or disadvantage in these two structures, but they are chosen flexibly according to different application scenarios and equipment requirements.
The reason why roller screws are widely used stems from its significant performance advantages: firstly, its friction coefficient is extremely low, and the transmission efficiency is as high as more than 90%, which significantly reduces energy loss compared with the traditional screw; secondly, by virtue of the precision manufacturing process, it is able to realize micrometer or even submicrometer positioning accuracy to meet the needs of high-precision machining; furthermore, it can not only realize high-speed feeding of up to a few meters per minute, but also accomplish micro-feeding of nanometer level, which is a good way to achieve high precision machining. Furthermore, it can achieve high-speed feeding up to several meters per minute, as well as nano-scale micro-feeding to adapt to different working conditions; in addition, its high axial stiffness makes it able to withstand large axial loads to ensure the stability of the transmission; finally, due to the absence of self-locking function and reversibility of transmission, making it unique in some special institutions in the application of value.
When calculating the speed of the roller screw, a variety of factors need to be considered. According to the mechanical transmission design specification, the guiding parameters need to be combined with the load size, transmission efficiency, working stroke and other factors to determine. The commonly used calculation formula is PH ≥ VMAX/NMAX (10), in which VMAX represents the maximum feed speed of the table (unit: mm/min), and NMAX indicates the maximum speed of the drive motor (unit: r/min), which provides an important basis for the selection of roller screw and speed calculation.
From the point of view of kinematics, there is a close relationship between the speed of the roller screw and the moving speed and pitch. The basic relationship equation is: screw speed × pitch = axial moving speed. From this, it can be deduced that the rotational speed of the roller screw is equal to the axial moving speed divided by the pitch. It should be noted that the above formula is only applicable to the case of a single thread. In the case of multi-head threads, it is also necessary to consider the influence of the number of thread heads on the speed calculation. At this time, the actual speed needs to be adjusted according to the number of thread heads on the basis of the above calculation results to ensure the accuracy of the calculation results. Through scientific and reasonable calculation method, the performance advantages of Roller Screw can be fully utilized to provide reliable guarantee for the efficient operation of mechanical equipment.
