SFV

1205/10/1510
1604/05/10
2004/05/10/20
2505/06/08/10/25

3204/05/06/08/10/20
4005/10/20
5005/10
6310/20
8010/20

The nuts of Taiwan TBI ball screw SFV series ball screw can be divided into: elbow type, circulator type and end cover type according to the circulation mode of steel balls. The specialties of these three circulation methods. The steel balls are circulated through the use of elbows. The steel ball is skimmed from the groove of the screw shaft and enters the elbow, and then returns to the groove to perform infinite circular motion.

TBI ball screw circulation characteristics

    There are two commonly used circulation methods: outer circulation and inner circulation. The ball sometimes loses contact with the lead screw during the cycle is called the outer cycle; the ball that always keeps in contact with the lead screw is called the inner cycle. Each closed circuit of the ball is called a column, and the number of leads contained in each closed circuit of the ball is called the number of turns. Each nut of the inner circulation ball screw pair has 2 rows, 3 rows, 4 rows, 5 rows, etc., and each row has only one turn; each row of the outer loop has 1.5 turns, 2.5 turns and 3.5 turns, etc. [2 ].

    1) Outer circulation: The outer circulation is that the ball returns to the screw nut through the spiral groove or the cannula on the outer surface of the nut to re-enter the circulation after the circulation process. As shown in Figure 2-3, the return methods of the outer circulation ball screw nut pair according to the ball circulation mainly include end cover type, intubation type and spiral groove type. Commonly used external circulation methods are end cap type; intubation type; spiral groove type. In the end cover type, a longitudinal hole is processed on the nut as the return passage of the ball. The cover plates at both ends of the nut are opened with the return port of the ball, and the ball enters the return pipe through this to form a circulation. Intubation type, which uses an elbow as the return pipe, this structure has good manufacturability, but because the pipe protrudes from the nut body, the radial dimension is relatively large. Spiral groove type, it is a spiral groove milled on the outer circle of the nut, through holes are drilled at both ends of the groove and tangent to the thread raceway to form a return channel, this structure is smaller in radial size than the intubation structure, but Manufacturing is more complicated. The outer circulation ball screw has a simple structure and manufacturing process and is widely used. The disadvantage is that it is difficult to smooth the joints of the raceway, which affects the stability of the ball raceway.

    2) Internal circulation: The internal circulation adopts the reverser to realize the ball circulation, and there are two types of reversers. Cylindrical convex key reverser, its cylindrical part is embedded in the nut, and the reverse groove 2 is opened at the end. The reverse groove is positioned by the round key 1 on the cylindrical outer surface and its upper end to ensure alignment with the direction of the threaded raceway. The oblate insert reverser, the reverser is a general round head flat key insert, the insert is embedded in the groove of the nut, and its end has a reverse groove 3, which is positioned with the outer contour of the insert. Comparing the two reversers, the latter is smaller in size, thereby reducing the radial dimension of the nut and shortening the axial dimension. However, the outer contour of the reverser and the dimensional accuracy of the groove on the nut are required to be relatively high.

Protection of TBI ball screw circulation

    1. Elimination of axial clearance. After the TBI ball screw pair is disassembled, in order to ensure the reverse transmission accuracy and axial rigidity, the axial clearance must be eliminated. The method for eliminating the gap of the double-nut ball screw pair is to use the relative axial displacement of the two nuts to make the balls in the two ball nuts respectively stick to the two opposite sides of the threaded raceway. When using this method to preload to eliminate the axial clearance, it should be noted that the preload should not be too large, otherwise the no-load moment will increase, thereby reducing the transmission efficiency.

    2. Regularly check the supporting bearings. Regularly check whether the connection between the screw support and the bed is loose, and whether the support bearing is damaged. If there is any problem, fasten the loose parts in time and replace the support bearing.

    3. TBI ball screw can be lubricated to improve wear resistance and transmission efficiency. Lubricants are divided into two categories: lubricating oil and grease. Engine oil for lubricating oil, No. 90~180 turbine oil or No. 140 spindle oil. Lithium-based grease can be used for grease. Lubricating grease is added to the threaded raceway and the housing space of the mounting nut, while lubricating oil is injected into the nut space through the oil hole on the housing. The grease on the ball screw should be replaced every six months, the old grease on the screw should be cleaned, and new grease should be applied. The ball screw pair lubricated with lubricating oil can be refueled once before each machine tool works.

    4. For the SFV ball screw pair and other rolling friction transmission components, as long as the abrasive particles and chemical active substances are avoided, it can be considered that these components work almost without wear. However, if dirt falls on the raceway or dirty lubricating oil is used, it will not only hinder the normal operation of the balls, but also cause a sharp increase in wear.

    5. Usually, a felt ring is used to seal the nut pair. The thickness of the felt ring is 2 to 3 times the pitch, and the inner hole is made into a threaded shape, so that it can tightly wrap the screw, and put it into the nut or sleeve. in the slot at the end. In addition to soft felt, the sealing ring can also be made of oil-resistant rubber or nylon. Since the sealing ring is in direct contact with the screw, the dust-proof effect is better, but it also increases the frictional resistance moment of the ball screw nut pair. In order to avoid this kind of friction resistance moment, a non-contact labyrinth seal ring made of relatively hard plastic can be used, and the inner hole is made in the opposite shape to the screw thread raceway, and a certain gap is left.

    6. For the screw rods exposed to the outside, protective covers in the form of spiral steel belts, telescopic sleeves, tapered sleeves, and folded plastic or artificial leather are generally used to prevent dust and abrasive particles from adhering to the surface of the screw. In addition to being similar to the protective cover of the guide rail, one end of these protective covers is connected to the end face of the ball nut, and the other end is fixed on the support seat of the ball screw. This will make it stronger.

TBI ball screw C7 grade is in stock, welcome new and old customers and friends to inquire and order.