In the field of mechanical transmission, shaft support block is a key basic component used to fix and support shaft parts (including ball screws, drive shafts, optical shafts, etc.). Its core function is to ensure that the shaft in the process of rotary or linear motion, to maintain precise positional accuracy and operational stability, and effectively avoid transmission errors caused by radial or axial displacement, vibration and noise problems, is to ensure the efficient and reliable operation of machinery and equipment is an important part.
First, the core role of the shaft support block mechanism
( 1 ) accurate positioning and solid support
shaft support block through the bolt or other fixed way tightly installed in the equipment base above, for the shaft parts to build up a rigid support point. In this process, it can strictly limit the radial runout (i.e., bending deformation) and axial runout of the shaft, so that the trajectory of the shaft accurately meets the design requirements. Take the ball screw drive system of CNC machine tools as an example, the support blocks at both ends of the screw need to be precisely installed and calibrated to ensure that the height of the axis of the screw is accurate, and once the installation deviation exceeds the allowable range, the nut will appear when running on the screw jamming phenomenon, which will lead to a significant drop in processing accuracy.
( 2) efficient load bearing
shaft support block has a strong bearing capacity, can effectively withstand the shaft in the operation process of radial force, axial force or composite load. Different types of machinery and equipment on the shaft support block bearing needs there are significant differences. For example, the machine tool spindle support block needs to withstand the powerful radial cutting force generated during the cutting process to ensure the stability of the spindle in the high-speed rotary cutting process; while the ball screw support block is mainly to resist axial thrust, that is, the table in the movement of the load generated by the reaction force, to ensure that the axial positioning accuracy of the screw, to maintain the smooth movement of the table.
( 3 ) Friction and wear control
In order to reduce the friction and wear between the shaft and the support block, some of the shaft support block has integrated bearings (such as deep groove ball bearings, angular contact ball bearings, etc.) or sliding bushings. By means of rolling or sliding friction, the direct contact between the shaft and the support block is converted into rolling or sliding contact, which significantly reduces the coefficient of friction, minimizes wear and effectively extends the service life of the transmission system. For example, in the high-speed rotation of the motor shaft support, the use of rolling bearing shaft support block can significantly reduce the friction resistance, improve the operating efficiency and stability of the motor; and in some low-speed heavy-duty or dust-proof requirements of the engineering machinery, sliding bearing support block with its compact structure, self-lubricating performance of the characteristics of the good, become the ideal choice.
Second, the typical structure of the shaft support block and classification system
(1) according to the support mode classification
Fixed support block (rigid support)
structural characteristics: fixed support block is usually made of high-strength aluminum alloy, cast iron or steel, with high rigidity and strength. When installed, the shaft is firmly fixed by means of interference fit or key connection, which can effectively limit the axial and radial movement of the shaft and provide stable support for the shaft.
Application Scenario: It is suitable for the scenarios that require high rigidity, such as the support of machine tool spindles. When the machine tool carries out high-speed cutting processing, the fixed support block can ensure the stability of the spindle and guarantee the machining accuracy; moreover, in the support of the transmission shafts of heavy-duty machinery, the fixed support block is also widely used to withstand huge loads.
Floating support block (flexible support)
Structural characteristics: Floating support block is generally used with deep groove ball bearings or cylindrical roller bearings, and its design concept is to allow the shaft to produce small axial displacement due to thermal expansion and contraction. The design concept is to allow small axial displacements due to thermal expansion and contraction of the shaft, etc. This structural design can effectively avoid the problem of stress concentration due to rigid fixation and improve the reliability of shaft operation.
Application Scenario: Commonly used in long shaft drive systems, such as the support of printing press cylinders, due to the long length of the cylinder, in the process of operation is prone to thermal expansion and contraction due to temperature changes, the use of floating support block can provide the necessary space for the expansion and contraction of the cylinder; in the high-precision ball screw system, one end is usually used in a fixed end of the installation, one end of the floating support block can ensure that the screw in the thermal expansion or contraction, not due to rigidity and rigidity, but also to ensure the reliability of the shaft. The floating end of the support block can ensure that the screw will not be deformed due to the rigidity limitation when it is extended by heat or contracted by cold, so as to ensure the transmission precision of the screw.
( 2) according to the type of bearing classification
rolling bearing support block
structure and principle: rolling bearing support block internal installation of deep groove ball bearings, angular contact bearings and other rolling bearings. The rolling body of the rolling bearing rolls between the inner and outer rings, which has a low coefficient of friction and can significantly reduce the resistance of the shaft in the process of rotation.
Application scenarios: especially suitable for high-speed rotation scenarios, such as motor shaft support, in the high-speed operation of the motor, rolling bearing support block can ensure the smooth rotation of the shaft, reduce energy loss; in some need for high-precision, high speed mechanical equipment, such as CNC machine tools spindle support, automated production line high-speed transmission shaft support, etc., the rolling bearing support block has also been widely used.
Sliding bearing support block
Structure and principle: Sliding bearing support block adopts copper alloy or self-lubricating material (such as graphite inlay bushing) as bearing material. An oil film or self-lubricating film is formed between the shaft and the bearing, and the friction between the shaft and the bearing is reduced by the lubricating effect of this film.
Application Scenario: Due to its compact structure and good self-lubricating performance, the sliding bearing support block is suitable for low-speed and heavy loads or environments with high dustproof requirements. For example, in construction machinery, such as excavators, loaders, drive shaft support, often face heavy loads, poor working conditions and a lot of dust challenges, sliding bearing support block can ensure the normal operation of the drive shaft by virtue of its excellent abrasion resistance and dust-proof performance; in some of the higher space requirements of the equipment, the compact structure of the sliding bearing support block also has obvious advantages.
Third, the key technical parameters and performance indicators of the shaft support block
(1) Load-bearing capacity
The load-bearing capacity of the shaft support block is determined by the strength of its material and bearing specifications. In the selection process, it must be matched according to the actual load demand of the shaft to ensure that the support block can safely and stably withstand radial and axial loads. For example, for some small machinery and equipment, the radial load of the shaft support block may only need to meet the ≤ 500N, axial load ≤ 200N can be; while in large heavy machinery and equipment, the support block load carrying capacity requirements will be greatly increased, may need to withstand thousands of Newtons or even higher loads.
( 2 ) installation compatibility
shaft support block installation compatibility is mainly reflected in its installation hole distance, hole diameter and other dimensional parameters need to accurately match the size of the shaft and the equipment base. At present, the common standards are ISO, JIS, etc., follow these standards to design and manufacture the shaft support block, in different brands and models of machinery and equipment to achieve better interchangeability and universality, reduce equipment design and maintenance costs. In the process of equipment upgrading and remodeling, installing a good compatibility of the shaft support block can be more convenient for replacement and installation.
Fourth, the shaft support block and related components of the synergistic application
(1) and the motor seat with
many mechanical equipment, the shaft support block and motor seat close cooperation, together constitute the shaft support system. Usually, the support block fixed screw end, the motor block connected to the other end, the installation accuracy between the two is critical to ensure that the coaxial deviation of the screw and the motor shaft ≤ 0.02 mm. If the coaxial deviation is too large, when the equipment is running, the shaft will produce eccentric vibration, not only accelerate the wear of the shaft, bearings and the support block, it will also affect the machining accuracy of the equipment and the stability of the operation, and may even lead to equipment failure. Equipment failure.
( 2) and coupling synergy
when the shaft and motor need to be flexibly connected, the shaft support block and coupling (such as diaphragm coupling) to work together. The coupling is able to compensate for mounting errors to a certain extent and at the same time realize torque transmission. In this case, the shaft support block provides stable support for the shaft, while the coupling ensures smooth power transmission between the shaft and the motor, even if there is some installation error, to ensure the normal operation of the equipment. In some automated production lines, due to the layout of the equipment and installation space limitations, it is often necessary to use this flexible connection, the shaft support block and coupling of the synergistic cooperation is particularly important.
V. Selection points and application examples of shaft support block
(1) Selection points
Load type: According to the actual type of radial and axial loads borne by the shaft, select the appropriate structure of the support block. If the axial load is large, should prioritize the use of angular contact bearing support block, because the angular contact bearing can withstand a large axial force; and for the main radial load bearing shaft, you can choose the deep groove ball bearing support block or sliding bearing support block.
Movement speed: for high-speed rotating scene (speed > 3000r/min), need to choose low-friction rolling bearing support block, and equipped with the corresponding lubrication system to ensure that bearings in high-speed operation can be fully lubricated to reduce friction and wear; in the low-speed operation of the equipment, according to the specific needs of the choice of rolling bearing support block or sliding bearing support block.
Environmental requirements: Different working environments have different requirements for shaft support blocks. In humid or dusty environment, sealing type support block should be selected, such as bearing support block with dust cover, to prevent moisture and dust from entering into the internal bearing and affecting the normal operation of the bearing; in high temperature scenarios, high temperature resistant materials need to be used in the manufacture of support block, such as ceramic bearing support block, to ensure that the support block in high temperature environment can still maintain good performance.
Contact Us
📞Tel: +86-8613116375959 (24 hours technical consultation)
📧Email: 741097243@qq.com
🌐Official website: https://www.automation-js.com/
