1. No preload or insufficient preload
When the ball screw without preload is placed vertically, the nut will rotate and slide due to its own weight; the screw without preload has considerable backlash, so it can only be used for machines with lower operating resistance. But the main concern is that the positioning accuracy is not required. Shanghai Silver determines the correct amount of preload for different applications, and adjusts the preload before shipment; therefore, when you order a ball screw, please be sure to detail the operation of the equipment.
2. Torsional displacement is too large
(1) Improper heat treatment, too thin hardened layer, uneven hardness distribution or too soft material, the standard hardness of steel ball, nut and screw rod are hrc 6266, hrc5862, hrc 5662 respectively.
(2) Improper design: too large slender ratio, etc. The smaller the slender ratio of the screw, the higher the rigidity. The limit of the slender ratio must be below 60. If the slender ratio is too large, the screw will have its own weight. Sagging.
3. Improper selection of bearings
Generally, ball screws must be matched with angular bearings, especially bearings with high pressure angle designs. When the ball screws bear axial load, general deep groove ball bearings will produce a certain amount of axial backlash Therefore, deep groove ball bearings are not suitable for this.
4. Improper bearing installation
(1) If the bearing is installed on the ball screw and the two are not properly fitted together, it will cause backlash under the condition of bearing the axial load. This situation may be caused by the screw shoulder being too long or too short .
(2) Poor perpendicularity between the bearing surface of the bearing and the v-shaped tooth axis of the locking nut, or the poor parallelism of the locking nut surfaces in the two corresponding directions, will cause the bearing to tilt; therefore, the locking screw at the screw shoulder The cap v-shaped tooth and the bearing surface must be processed at the same time to ensure the verticality, and it is better to process it by grinding.
(3) Fix the bearing with two lock nuts and spring washers to prevent loosening during operation.
5. Insufficient rigidity of the nut seat or bearing seat. If the nut seat or bearing seat is not sufficiently rigid, it will be deflected due to the weight of the component itself or the load of the machine. This method is used to detect the rigidity of the nut seat, and similar tests can also be used to detect the rigidity of the bearing seat.
6. Improper assembly of nut seat or bearing seat
(1) The component is loose due to vibration or the lack of a fixed pin. A solid pin is used to replace the spring pin to achieve the purpose of positioning.
(2) The nut fixing screw cannot be locked because the fixing screw is too long or the screw hole of the nut base is too shallow.
(3) The nut fixing screws are loose due to vibration or lack of spring washers
Contact Us
E-mail: sales@gyballscrew.com Tel(WhatsApp): 17769816967
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