Requirements for spindles in spinning process

spinning spindle

spinning spindle

    • Stable operation and small vibration in a wide speed range;
    • Wear resistance and long service life;
  • Low power consumption;
  • Low noise;
  • Large bearing capacity. The key is to reduce vibration and wear. Any spindle will inevitably vibrate and wear during rotation. Violent vibration will cause bobbin jumping, yarn breakage or poor forming, and accelerate the wear of parts, especially when rotating at high speed.

 

Vibration

When the working speed of the spindle is close to the natural frequency of the spindle’s natural vibration, there will be resonance and great amplitude. At this time, the spindle speed is called the critical speed of the spindle. The spindle rod is a continuous elastic body, which theoretically has infinite natural frequencies, which is related to the mass distribution and stiffness of the spindle rod; The complete set of spindles (including spindle rod, spindle disc and supporting parts) is a complex vibration system, which also has multiple natural frequencies, so the spindle has multiple critical speeds. The working speed of the roving frame is far lower than the first critical speed of the spindle. If the dynamic balance between the spindle and the spindle wing is poor, the vibration will increase significantly with the increase of the spindle speed. Therefore, in order to improve the spindle speed of roving frame, we must improve the structure of spindle and spindle wing and improve the manufacturing quality. The working speed of the spinning spindle is between the first and second critical speeds. If it is accelerated after crossing the critical speed, the vibration of the spindle will improve. Comparing the vibration characteristic curves of the two spindles, it can be seen that the vibration performance of the spindle with elastic support is superior.

The spinning spindle has longitudinal vibration and transverse vibration when rotating at high speed. Longitudinal vibration refers to the movement of spindle and bobbin up and down. The lateral vibration is commonly known as spindle shaking. In the early stage, it was detected by the numbness of the hand at the top of the spindle. Now the photoelectric vibration meter is widely used to directly display the amplitude of the top of the spindle. Transverse vibration is actually the combination of three vibration phenomena:

  • natural vibration;
  • Forced vibration;
  • Self excited vibration.

Natural vibration is caused by the action of instantaneous external force, such as the impact of spindle belt joint, etc. its vibration range depends on the initial conditions, and the vibration frequency is the natural frequency, which will gradually decline and disappear; Forced vibration is the vibration caused by the continuous action of periodic external force on the spindle, such as the eccentricity or bending of spindle rod, disc, bobbin and other rotating parts, as well as the dynamic deformation of bobbin at high speed. At this time, the vibration frequency is equal to the working speed of the spindle, and the vibration range value depends on the mass, eccentricity and working speed; Self excited vibration is the vibration excited by the system itself, such as the friction caused by the abnormal contact between the spindle bottom and the spindle rod, or due to the internal friction of the spindle rod, spindle disc and other materials. Once excited, this vibration will continue to exist and will not disappear. Its vibration frequency is roughly equivalent to the natural frequency of the spindle, and the vibration range value depends on the structural state of the vibration system.

abrasion

Spindle wear occurs at the spindle tip and bearing stop. The normal wear of the spindle tip is smooth and round, and the serious wear of abrasive particles makes the spindle tip appear gourd shape. When the spindle bottom and the spindle tip are not on the common axis, the spindle rod will move, resulting in sliding wear of side contact. Normal bearing gear wear reduces the accuracy and increases the fit clearance, resulting in increased vibration. If the upper bearing is short of oil, the bearing gear will wear faster. Generally, under certain load conditions, the wear degree of spindle depends on the material, structure, hardness, metallographic structure, geometric accuracy and finish of spindle rod, spindle bottom and bearing.

Bare Blade Spindle

Bare Blade Spindle

take steps

In order to reduce the vibration and wear of high-speed spindle, we should not only pay attention to improving the manufacturing quality of parts and improving heat treatment methods, but also focus on the structural type of spindle, and optimize the support, elasticity and damping parameters, so as to control the critical speed and eliminate self-excited vibration. For spindles bearing heavy loads, the geometry of the spindle tip and the structure of the spindle bottom must be considered. In addition, the advantages and disadvantages of bobbin have a great impact on the vibration energy of spindle, especially after high speed. The function of spindle oil is not only to lubricate parts, but also to damp and eliminate vibration, and affect power consumption.

spindle

spindle