Attentions for Installation and Debugging of Spindle Bearings
(1) Installation and debugging of a single bearing: when assembling, the eccentricity of the main shaft positioning bore and the diameter of the main shaft and the eccentricity of the bearing inner ring and raceway are as close as possible, and the direction is opposite, so that the eccentricity after assembling can be reduced.
(2) Installation and debugging of two bearings: When two supporting spindle bearings are installed, the direction of eccentricity of the front and rear supporting bearings should be the same, and the size of eccentricity should be selected appropriately. The accuracy of the front bearing should be one grade higher than that of the rear bearing, so as to minimize the eccentricity of the front positioning surface of the assembled spindle components. When disassembling spindle bearings in maintenance machine tools, because the original manufacturer has adjusted the eccentric position of bearings, it is necessary to mark the position of circumferential direction before disassembly to ensure that the original relative position of bearings and spindles remains unchanged after reassembly, so as to reduce the impact on spindle components.
2. Attentions in installation and commissioning of ball screw nut pairs. Ball screw nut pairs are only used to withstand axial load. Radial force and bending moment may cause additional surface contact stress and other bad loads on ball screw pairs, which may cause permanent damage to the screw. Therefore, when ball screw nut pairs are installed in machine tools, attention should be paid to:
(1) Ball nuts should move in an effective stroke. Limitations must be arranged at both ends of the stroke to avoid the nuts from leaving the screw shaft and causing the balls to fall off.
(2) Because of the high transmission efficiency of ball screw nut pair, it can not self-lock. When used in vertical direction transmission, if the weight of components is not balanced, it is necessary to prevent the reverse transmission caused by the weight of components after the transmission stops or the motor loses power. The methods of preventing the reverse transmission are available: worm wheel and worm drive, electric brake, etc.
(3) The axis of the screw must be parallel to the axis of the supporting guide rail. The center of the bearing seat at both ends of the machine tool must be in line with the center of the nut seat at three points.
(4) When the ball screw nut pair is installed in the machine tool, do not remove the nut from the screw shaft. If it must be unloaded, the auxiliary sleeve should be used, otherwise the ball may fall off during loading and unloading.
(5) When the nut is loaded into the mounting hole of the nut seat, collision and eccentricity should be avoided.
(6) In order to prevent chips from entering and wearing the ball screw nut pair, protective devices such as wrinkle shield and spiral steel belt shield can be installed to completely protect the screw shaft. In addition, dustproof rings can be added at both ends of screw nuts when there is more floating dust.
3. Notices for installation and debugging of linear rolling guide (1) Handle it lightly during installation to avoid impact on the linear accuracy of the guide.
(2) It is not allowed to dismantle the slider from the guide rail or push it back beyond the stroke. If it is difficult to install the slider, the guide rail should be used when the slider needs to be removed.
(3) When linear rolling guides are used in pairs, they are divided into main and auxiliary guideways. Firstly, the main guideway pairs are installed. The reference side of the guideway is set close to the reference side of the installation step, and the bolts are fastened. Then, the auxiliary guideway pairs are positioned and installed on the basis of the main guideway pairs.
