Some characterics of Ball Screw pair

Ball Screw pair, also known as ball screw pair, ball screw pair. It is composed of two sets of screws and nuts. It is the most accurate and most commonly used transmission device in transmission Machinery.
Introduction Edit Broadcast
When moving an object, it is generally necessary to transmit the motion generated by the power directly or indirectly through other mechanisms to the final moving part. Taking the engine as an example, in the engine, the piston moves up and down due to the combustion of gasoline, and finally transmits it to the wheel through the intermediate mechanism to make it rotate.
In today's world, devices that can represent machinery and have various motion mechanisms can be said to have some form of motion transmission mechanism. Ball screw pair is the most reasonable product to convert rotary motion into Linear Motion, or convert linear motion into rotary motion.
The ball screw pair is a screw transmission element with steel balls as rolling elements between the screw and the nut. It converts rotational motion to linear motion, or linear motion to rotational motion. Therefore, the ball screw pair is not only a transmission element, but also a mutual conversion element between linear motion and rotary motion. [1]
Specialty Editing Broadcast
Compared with the sliding screw pair, the driving torque is 1/3. Since there are many balls rolling between the screw shaft and the screw nut of the PRTT ball screw pair, higher motion efficiency can be obtained. Compared with the previous sliding screw pair, the driving torque is less than 1/3, that is, the power required to achieve the same motion result is 1/3 of the sliding screw pair. Very helpful in a power saving environment.
High precision guarantee
The ball screw pair is continuously produced with the world's highest level machinery and equipment made in Japan, especially in the factory environment of grinding, assembly, and inspection of each process, the temperature and humidity are strictly controlled, due to the perfect quality management. The system enables the accuracy to be fully guaranteed.
Microfeed possible
Since the ball screw pair uses ball motion, the starting torque is extremely small, and there will be no creeping phenomenon like sliding motion, which can ensure accurate micro-feeding.
No backlash and high rigidity
The ball screw pair can be pre-pressed, and the axial clearance can reach a negative value due to the pre-pressure, thereby obtaining higher rigidity (by adding pre-pressure to the balls in the ball screw, when it is actually used in mechanical devices, etc., due to the ball The repulsive force can increase the rigidity of the silk mother).
High speed feed possible
The ball screw pair can achieve high-speed feed (movement) due to its high motion efficiency and low heat generation [2] .
Circular way
There are two commonly used circulation methods: outer circulation and inner circulation.
The ball is sometimes out of contact with the screw during the circulation process is called the outer loop; the ball is always in contact with the screw is called the inner loop. Each closed loop of the ball is called a row, and the number of leads contained in the closed loop of each ball is called the number of turns. Each nut of the inner circulation ball screw pair has 2, 3, 4, 5 rows, etc., and each row has only one circle; each row of the outer circulation has 1.5 circles, 2.5 circles, and 3.5 circles.
(1) External circulation: The external circulation is that the balls return to the screw and nut through the spiral groove or cannula on the outer surface of the nut and re-enter the circulation after the end of the circulation process. The return methods of the external circulation Ball Screw Nut pair according to the ball circulation mainly include end cap type, intubation type and spiral groove type.
For the end cap type, a longitudinal hole is machined on the nut as a return passage for the balls. The cover plates at both ends of the nut are provided with return openings for the balls, from which the balls enter the return pipe to form a circulation. Intubation type, which uses elbows as return pipes, this structure has good manufacturability, but because the pipes protrude from the outside of the nut, the radial size is large. Spiral groove type, it mills a spiral groove on the outer circle of the nut, and drills through holes at both ends of the groove and is tangent to the threaded raceway to form a return channel. This structure is smaller than the intubation structure in radial size, 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 seam of the raceway, which affects the stability of the ball raceway.
(2) Inner circulation: Inner circulation adopts reverser to realize ball circulation, and there are two types of reverser. Cylindrical convex key reverser, its cylindrical part is embedded in the nut, and the end is provided with a reverse groove. The reverse groove is positioned by the cylindrical outer surface and the round key at the upper end to ensure alignment with the thread raceway direction. 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 the end is provided with a reverse groove, 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 dimensional accuracy of the outer contour of the reverser and the groove on the nut is relatively high.
Construct Edit Broadcast
The ball screw pair is unique in the structure of the nut part. According to the circulation mode of the ball, it can be divided into
①There is a ball rotating channel between the elbow screw pair and the nut. The ball produces an axial load on the channel. After the ball rolls around the screw shaft, it enters the elbow embedded in the nut. And it circulates again to the load zone along the elbow, thus making an infinite rolling motion. This product is the most popular and popular product among the ball screw pairs, and can be widely used for various purposes.
② ball return device type.
③ End environment type [1].
Use Notes Edit Broadcast
The following items should be paid attention to when using the ball screw pair:
1. The rolling nut should move within the effective stroke. If necessary, limit positions should be arranged at both ends of the stroke to prevent the nut from breaking away from the screw shaft and causing the balls to fall off.
2. The ball screw pair cannot be self-locking due to its high transmission efficiency. When it is used for vertical transmission, if the weight of the components is not balanced, it must prevent the reverse transmission caused by the weight of the components after the transmission stops or the motor loses power. Anti-reverse transmission methods can be used turbo screw transmission, hydraulic electrical brakes and overrunning clutches.