Vòng bi cầu chặn hai hướng

VÒNG BI CẦU CHẶN HAI HƯỚNG

Double direction thrust ball bearings are separable, consisting of one shaft washer with groove on both sides, two housing washers and two cage-ball assemblies. Double direction thrust ball bearings can carry only axial loads in both directions, but any radial loads. Hense they can locate the shaft in two directions. Their housing washer and cage-ball assembly are the same those of the relevant single direction bearings.

Dimensions

The boundary dimension of the thrust ball bearings listed in the following bearing tables are in conformity with ISO104.

Tolerances

HRB basic thrust ball bearings generally have P0 class tolerances, On customer’s demand, the bearings can be supplied upto P6, P5 and P4 class tolerances. Dimensional tolerance are also obtained from the tolerance tables for thrust bearings.

Cages

HRB thrust ball bearings are accompanied with two kinds of cages, pressed steel or machined brass, specified in the table below.

* The listed bearing bore code is the last two figures in the bearing designation, so that the bearing bore size can be obtained from the code multiplied by 5.

Minimum rolling bearing load

During high speed running, the inertia forces of the cage and balls may cause sliding between the ball-to-raceway contacts in the thrust ball bearings, easy to generate heat and wear on working surface. In order to avoid sliding of ball to the raceway, a certain minimum axial load F_amin has to be exerted on the thrust ball bearing while working.

F_amin ≥ A(n_max/1000)²

where:

F_amin: minimum required axial load, kN
A: minimum axial load factor, listed in the bearing tables
n_max: maximum working speed, rpm

In general the bearing support mass adding external forces always goes beyond the minimum required axial load. If not, an additional preload has to be exerted, for example by a spring.

Equivalent static bearing load

Single and double direction thrust ball bearings: P₀ = F_a

Equivalent dynamic bearing load

Single and double direction thrust ball bearings: P = F_a