news

thrust ball bearing

January 16, 2020

Thrust ball bearings are designed to withstand thrust loads at high speeds, and consist of washer-like rings with ball rolling grooves. Because the ferrule is seat cushion-shaped, thrust ball bearings are divided into two types: flat base cushion type and self-aligning spherical cushion type. In addition, this type of bearing can support axial loads but not radial loads.
Chinese name thrust ball bearing classified single-way, two-way use Mechanical parameters Speed, load
table of Contents
1 Composition
2 types
3 Features
4 uses
5 Assembly
Composition editor
Thrust ball bearing: Thrust ball bearing is composed of three parts: seat ring, shaft ring and steel ball cage assembly. The shaft ring is matched with the shaft, and the seat ring is matched with the housing. [1]
Category edit
kind:
According to the force situation, it is divided into one-way thrust ball bearings and two-way thrust ball bearings.
Thrust ball bearing
Thrust ball bearing
One-way thrust ball bearings can withstand unidirectional axial loads. Two-way thrust ball bearings can withstand two-way axial loads, of which the collar and the shaft cooperate. The bearing with a spherical mounting surface has a self-aligning performance, which can reduce the impact of mounting errors. Thrust ball bearings cannot bear radial loads, and the limiting speed is low. [1]
Features edit
1. Available in unidirectional and bidirectional types
Thrust ball bearing
Thrust ball bearing
2. In order to tolerate installation errors, whether it is unidirectional or bidirectional, you can choose spherical self-aligning spherical seat cushion type or spherical seat type. 3. High-quality steel—Using ultra-clean steel that can extend bearing life by up to 80% 4. High grease technology—NSK's lubricant technology can extend grease life and improve bearing performance 5. High-grade steel balls— Quiet and smooth when rotating at high speed 6. With the ferrule in the option, installation errors can be tolerated. [1]
Purpose edit
Thrust ball bearings are only suitable for parts that bear axial load on one side and have low speed, such as crane hooks, vertical water pumps, vertical centrifuges, jacks, low speed reducers, etc. The bearing's shaft washer, seat washer and rolling element are separated and can be assembled and disassembled separately. [1]
Assembly editing
There are two key points in the assembly of thrust ball bearings. One is the control of the press-fit quality of the cage and the steel ball, and the other is the control of the nominal height T after the bearing is assembled. In addition, since the shaft and seat rings can be separated, it brings a management problem. It is to prevent the mixing of imported bearing parts. M-type stamping cages use flanged assembly molds. After pressing, it is required that the steel ball rotates flexibly in the pocket, but it cannot fall off from the pocket, and the technical regulations check the amount of movement of the ball in the pocket. If the imprint of the solid cage is too deep, the movement of the steel ball will be small, and the connection between the imprinted convex portion and the cage is too small and the strength is insufficient, which will easily cause the block phenomenon and cause the cage to be scrapped. The difference between the inner diameter of the small thrust ball bearing seat ring and the shaft ring is small, and there is no obvious difference between the two sets. In order to prevent the phenomenon of mixed sleeves, that is, a set of bearings is found to be both a seat ring or a shaft ring. This requires certain measures. Usually, the auxiliary ring is used to distinguish between the draw ring and the seat group when the sleeve is fitted, or the inner diameter plug gauge is used to check the inner diameter size before sampling the nominal height. If the inner diameter of the seat ring has obvious quenching and heating oxidation color or is not ground, it is not necessary to check the inner diameter size. The difference between the shaft ring and the seat ring can be clearly seen, and it is not easy to mix. After the thrust ball bearing is assembled, the nominal height T needs to be measured to confirm whether it is qualified. When measuring, use a height block or standard to calibrate and measure the load. The bearing needs to be rotated dozens of times, and it must reach the minimum height. [1]
When the thrust ball bearing is running at high speed, the contact angle between the steel ball and the radial plane of the raceway will be affected by centrifugal force, which will cause the steel ball to slide relative to the raceway. Adhesive wear caused by this sliding can damage the bearing. To prevent such damage, the minimum load on the thrust ball bearing must be guaranteed, see formula 1 or formula 2, whichever is greater. [1]
Formula 1: Famin = K ・ n * n
Formula 2: Famin = Coa / 1000
Famin: minimum axial load (N)
K: minimum axial load factor
n: speed (per minute)
Coa: Basic static load rating (N) [1]
One-way thrust ball bearings can only bear loads in one direction. If they bear loads in two directions, a two-way thrust ball bearing must be selected. Thrust ball bearings must have a minimum or preload. When the shaft is vertical, the weight of the shaft usually exceeds the minimum load. At this time, due to the influence of the axial external load in the opposite direction, the applied load may be reduced.