Last updated on November 19th, 2022 at 11:29 am
Ball Screw Features
Table of Contents
1. Small friction loss, high transmission efficiency
Because there is a lot of ball rolling between the screw shaft and the screw nut of the ball screw pair, high movement 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. ทดลองเล่นสล็อตPP Great for saving electricity.
หากอยากเป็นสมาชิกกับเรา สล็อต ทดลองเล่นฟรี ถอนได้2021 ทำด้วยขั้นตอนง่าย ๆ ทำการสมัครเป็นสมาชิก ผ่านระบบออโต้ ไม่มีความยุ่งยาก สมัครได้ใช้เวลาไม่นาน เพียง 1 นาที กรอกรายละเอียด ตามช่องว่างที่ระบบของเรา จากนั้น ส่งยืนยันข้อมูล รอการอนุมัติ สามารถร่วมสนุกกับเราได้ทันที เป็นรูปแบบใหม่ มีทั้งการทดลองเล่นเกมฟรี
2. High precision
Ball screw pair is generally produced continuously with the world’s highest level of machinery and equipment, especially in the factory environment of grinding, assembly and inspection of each process, due to a perfect quality management system, temperature and humidity are strictly controlled. Accuracy is fully guaranteed.
3. High speed feed and micro feed can be realized
Because the ball screw pair adopts ball movement, the starting torque is very small, and there will be no peristaltic phenomenon like sliding movement, which can ensure accurate micro feed.
4. High axial stiffness
The ball screw pair can be pre-tightened. Due to the preloading force, the axial clearance can reach negative value, so as to obtain higher stiffness (by adding preloading force to the ball in the ball screw, when actually used in mechanical devices, the stiffness of the nut part can be increased due to the repulsive force of the ball).
No self-locking, good reversibility of transmission
Ball screw pair protection
Ball screw pair can be lubricated to improve wear resistance and transmission efficiency. Lubricants are divided into two categories: lubricants and greases. Lubricating oil, No. 90-180 turbine oil or No. 140 spindle oil. Grease can be lithium based grease. Add grease to the threaded raceway and the housing space of the mounting nut, and inject lubricating oil into the nut space through the oil holes in the housing.
Ball screw pairs and other rolling friction transmission elements can be considered to operate almost without wear as long as the entry of abrasive particles and chemically active substances is avoided. However, if dirt falls on the raceway, or dirty lubricating oil is used, it will not only hinder the normal operation of ball bearings, but also rapidly increase wear.
Usually, a felt ring is used to seal the nut pair. The thickness of the felt ring is 2 ~ 3 times the pitch, and the inner hole is made into a threaded shape to tightly wrap the lead screw and fit the grooves at both ends of the nut or sleeve. Inside the hole. In addition to soft felt, the sealing ring can also be made of oil-resistant rubber or nylon. Because the sealing ring is in direct contact with the lead screw, the dustproof effect is better, but the friction resistance torque of the ball screw nut is also increased. To avoid this friction torque, a non-contact labyrinth seal made of hard plastic can be used, and the inner hole is made into the opposite shape of the threaded raceway, with a certain clearance.
For the exposed lead screw, the protective sleeve in the form of spiral steel belt, telescopic sleeve, conical sleeve, folded plastic or artificial leather is generally used to prevent dust and grinding particles from adhering to the surface of the lead screw. One end of these protective covers is attached to the end face of the ball nut and the other end is fixed to the bearing seat of the ball screw, except for protective covers similar to the guide rail. This will make it stronger.
Main parameters of ball screw
The primary parameter of the thread
1) Outer diameter d(large diameter)(d) — the diameter of the imaginary cylinder surface that coincides with the top of the external thread — also known as the nominal diameter
2) Inner diameter (small diameter)d1 (d1) — the diameter of an imaginary cylinder surface that coincides with the root of the external thread, and the calculated diameter of the dangerous section is used for strength calculation
3) Pitch diameter d2 — the diameter of virtual cylinder with equal tooth thickness and intertooth width on axial section, which is approximately equal to the average thread diameter d2≈0.5(d+d1).
4) Pitch P — the axial distance between adjacent teeth corresponding to two points on the bus of a cylindrical surface of medium diameter
5) Lead (S) — the axial distance between two points corresponding to the bus of the middle diameter cylinder surface of two adjacent teeth on the same helix
6) line number n — screw number, generally for the convenience of manufacturing n≤4, pitch, lead, the relationship between the number of lines :S=nP
7) Helix Angle ψ – The Angle between the tangent of the helix and the plane perpendicular to the helix axis on the middle diameter cylinder surface.
8) contour Angle α — the Angle between the two sides of the thread contour on the thread axial plane 9) contour bevel Angle β — the Angle between the side of the thread contour and the vertical plane of the thread axis. Asymmetric tooth profile
The main geometric dimensions of various threads (except rectangular threads) can be found in the relevant standards – the nominal dimension is the outside diameter of the thread, and the pipe thread is approximately equal to the inside diameter.
The self-locking condition of screw pair is that the lift Angle of thread is less than or equal to the equivalent friction Angle of screw pair.
The transmission efficiency of the screw pair is the ratio of the effective work and the input work when the nut rotates once.
The circular force needs to overcome the axial force Q to rise at a constant speed
Check and maintain ball screw pair
Ball screw faults are varied and have no fixed pattern. Some faults are progressive, must have a process of development, and become more and more serious as the use of time increases; A combination of adverse factors and the outside world. Therefore, through the correct detection, to determine the real cause of the fault, is the premise of rapid and accurate maintenance.
1) Check and repair the clearance of ball screw nut and support system
When the CNC machine tool reverse error is large, the positioning accuracy is not stable, the knife printing in the quadrant, the first