Function of ball screw bearing block
As the "stable base" of ball screw transmission system, the core function of ball screw bearing block is to guarantee the stable operation of ball screw in high speed and heavy load working condition through precise positioning and rigid support, the specific role is reflected in the following aspects:
I, Positioning and fixation, limiting the axial movement of the screw
Ball screw in the transmission process (such as driving the table linear movement), will be due to the reaction force of the nut to produce axial thrust, if the screw ends are not fixed constraints, prone to axial movement along the direction of the drive precision decline. The
support strictly limits the axial displacement of the screw by rigidly connecting with the shaft end of the screw (e.g., with the lock nut and shoulder positioning) to ensure its stable rotation in the preset axial position.
Some supports are designed with adjustable clearance structure (such as double-row angular contact ball bearing set), which can eliminate bearing clearance through preloading and further inhibit the axial runout of the screw (controlled within 0.01mm), which is suitable for high-precision feeding system (e.g., mold processing machine tools).
Second, bearing and force transmission, dispersing the composite load
Ball Screws need to withstand multi-directional loads when running: axial work load (such as table gravity, cutting force), radial bending moment (such as the additional force caused by the self-weight of the screw or installation deviation), and the centrifugal force when rotating.
The support distributes these loads to the machine frame by means of internal bearings (e.g. deep groove ball bearings for radial forces and axial bearings for axial forces) to avoid bending and deformation of the screw due to excessive forces at a single point.
In heavy load scenarios (such as heavy-duty press screw drive), the support is made of high-strength cast iron (e.g. HT300) or cast steel, with reinforcing rib structure, which can withstand several tons of axial thrust and thousands of oxen of radial force, to ensure the long-term and stable operation of the screw.
Third, to ensure rotational accuracy, reduce vibration and noise
The transmission accuracy of ball screws depends on the concentricity of rotation: if the screw shaft end swings too much (radial runout exceeds 0.02mm), it will lead to fluctuations in the fit gap between the nut and the screw and cause transmission errors.
The support is fitted with high precision bearings (e.g. class P5) through precision machined bearing bores (tolerance class IT6), which strictly control the radial runout and end runout of the screw to ensure concentricity during rotation.
In the high-speed scenario (screw speed >3000r/min), the support adopts dynamic balancing design (balancing accuracy G2.5 grade or above), which reduces centrifugal force vibration due to uneven distribution of mass, and lowers the operation noise (controlled below 75dB).
Adapting to installation scenarios and simplifying system integration
ball screw mounts adopt standardized interface design, which can be quickly adapted to different installation requirements.
The flange type support is bolted directly to the end face of the frame, which is suitable for the "simple support structure" in which the two ends of the screw are fixed.
Bearing seat type support can adjust the position along the direction of the guide rail, adapting to the length deviation of the screw and facilitating the alignment with the motor, coupling and other components.
Compact support (height <50mm), on the other hand, is suitable for space-constrained scenarios (e.g. small automation equipment), saving installation space while ensuring support strength.
Five, protection and sealing, adapting to complex environments
In dusty, humid or coolant splashing environments (e.g. CNC machine tools, food processing equipment), the support needs to be protected.
Adopt labyrinth seal or rubber seal to prevent external pollutants from intruding into the internal bearing and avoid grease contamination or bearing rust.
In high temperature environments (such as heat treatment equipment, screw drive), the support is equipped with a heat sink or forced air cooling device to control the working temperature of the bearings below 80 ℃, to prevent grease failure or bearing annealing.
Summary
The core value of ball screw bearing block is **"stable support + accurate guidance "**, through positioning constraints, load transfer, precision guarantee and other functions, it becomes the key node connecting the screw and equipment frame. The performance directly affects the transmission accuracy, load capacity and service life of the ball screw, and is an indispensable supporting component in all kinds of transmission systems.
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