Lead screw lifting machines, also known as spiral drive mechanisms, are primarily used to convert rotational motion into linear motion or vice versa. There are those mainly for transmitting motion, such as the feed screw of machine tool worktables, and others for adjusting the relative positions of parts. The screw jack consists of a worm gear reducer and a screw, with the减速 component being the worm gear drive, which uses the worm to drive the worm gear for deceleration. The worm gear acts as the nut for the lifting screw, matching with the lifting screw.
Features of Screw Jack:
1The working principle involves ball bearings placed between the screw thread raceways of the lead screw and nut.
2When the screw or nut rotates, the ball bearings roll along the thread groove, resulting in rolling friction between the screw and nut during relative movement. To prevent the ball bearings from rolling out of the groove, return guide devices are installed at both ends of the nut's spiral slot.
3They form a closed loop with the threaded raceways, allowing the ball bearings to circulate within the nut's raceway.
The transmission types of screw jacks are based on the relative movement combinations of the screw and nut. There are two basic types of fundamental transmission for screw jacks.
(1)Nut fastening, screw shaft rotation and movement. This type of transmission is simpler in structure and achieves higher transmission accuracy due to the nut's inherent supporting role, which eliminates additional axial movement that might occur in screw shaft bearings. However, its axial dimension should not be too long, as it would reduce rigidity. Therefore, it is only suitable for applications with short travel distances.
(2)Screw shaft rotation and nut movement require the nut's rotation to be limited, necessitating a guiding device. It features a compact structure, good screw shaft rigidity, and is suitable for applications with extended working travel.
The NM series screw jack is widely used in various industries such as machinery, metallurgy, construction, chemical industry, culture, and public health. It can accurately control and adjust the lifting or advancing height according to a certain program. It can be directly driven by an electric motor or other power sources, or operated manually. The input speed does not exceed 1500 r/min, with a lifting speed of 2.7 m/min. It comes in different structural types and assembly methods, with lifting heights tailored to customer requirements.
The NM series screw jack has the advantages of low noise, smooth transmission, and flexible operation during use; Moreover, to ensure safety during operation, the jack is equipped with an automatic locking feature. In the event of a problem with the equipment, the jack can self-lock and stop movement, thereby ensuring the safety of the production environment and personnel to some extent.
