What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The fixing screw proposed by Guangdong Yueluo Hardware Industry Co., Ltd. has a screw body 1, and the axial surface of the screw body 1 is formed with extending screw teeth 6, and the axial surface is a column along the central axis direction of the cylinder of the screw body 1. The body surface has a hemispherical screw tail 7 at the bottom, and a screw head 2 at the top. The upper surface of the screw head 2 is provided with a slot (not shown). The screw body 1 is composed of the upper tapered rod 4 and the lower cylindrical screw 5. The tapered rod 4 is an inverted cone, the diameter of its circular upper surface and the diameter of the screw mounting hole 10. equal. The fixing screw also has a washer 3, the washer 3 is arranged between the screw head 2 and the screw body 1, the lower surface of the cylindrical washer 3 has a number of teeth 8, the teeth 8 are along the The upper surface of the inverted cone of the tapered rod 4 and the edge of the washer 3 are connected to form a straight convex strip 15 extending outward; the convex strip 15 can also be designed in an arc shape. The fixing screws for installation proposed by Guangdong Yueluo Hardware Industry Co., Ltd. can be made of metal materials in one piece. As shown in Figure 3, it is a schematic diagram of the installation of Guangdong Yueluo Hardware Industry Co., Ltd. for PCB board fixing. When installing, first pass the screw body 1 of the fixing screw through the mounting hole 10 and the copper column 11 provided on the PCB board 9, so that the tail 7 of the screw reaches the mounting hole 13 on the casing 12, and then use the tightening tool 14 to insert the screw At the notch on the top of the head, forcefully press the inverted cone design taper rod 4 of the screw body 1 into the mounting hole 10, so that the tail 7 passes through the mounting hole 13. Due to the outer diameter D at the bottom of the taper rod and the screw mounting hole The aperture size of 10 is equal, and the fixing screws are pressed and fixed, so that the PCB board 9 can be automatically corrected in the process of fixing its front, back, left and right deflections, and the accuracy of the installation position of the PCB board 9 can be ensured. As shown in Figure 4, after the fixing screw is screwed into the casing, the washer 3 is fully contacted and pressed on the PCB board 9, and the PCB board 9, the copper column 11 and the casing 12 are firmly connected together without sliding. . The teeth 8 on the washer 3 are in full contact with the surface of the PCB board 9, so that a ground wire path is set up between the PCB board 9 and the casing 13 by the metal fixing screw 1, thereby ensuring that the PCB board 9 is fully grounded , the design of the teeth 17 on the washer 3 also has a non-slip function. The fixing screws for installation designed by Guangdong Yueluo Hardware Industry Co., Ltd. make use of the cooperation, friction and electrical conductivity in the mechanical connection, which fully guarantees the firm installation of the PCB board and the chassis and the good grounding of the PCB board. Moreover, the ellipsoid tail of the fixing screw The surface is relatively smooth, even if the mounting holes are exposed, it will not cause scratches on the hands and desktop. The above is only the embodiment of Guangdong Yueluo Hardware Industry Co., Ltd., and does not limit the scope of Guangdong Yueluo Hardware Industry Co., Ltd., any equivalent structure made by using the contents of the description and drawings of Guangdong Yueluo Hardware Industry Co., Ltd. or etc. Effective process transformation, or direct or indirect application in other related technical fields, are also included in the protection scope of Guangdong Yueluo Hardware Industry Co., Ltd.
1. When the main body is large-scale equipment, accessories need to be installed, such as sight glass, mechanical seal seat, deceleration frame, etc. The stud bolts used at this time, one end is screwed into the main body, and the other end is equipped with nuts after the accessories are installed. , Since the accessories are often disassembled, when the main body and the accessories are directly connected by bolts, the main body threads will be worn or damaged over time, and it is very convenient to use studs to replace them. 2. When the thickness of the connecting body is very large and the bolt length is very long, stud bolts will be used. The purpose of anti-loosening of stud connection In actual work, the external load has vibration, change, high temperature creep of the material, etc., which will reduce the friction force, the positive pressure in the thread pair disappears at a certain moment, and the friction force is zero, thus making the threaded connection loose. , if repeated action, the threaded connection will loosen and fail. Therefore, it is necessary to prevent loosening, otherwise it will affect the normal work and cause accidents.
1. Other names: root nut, anti-loosening nut, nut. 2. Purpose: To lock the outer joint of the through wire or other pipe fittings. The working principle of the nut is to use the friction between the nut and the bolt for self-locking. However, the reliability of this self-locking is reduced under dynamic loads. In some important occasions, we will take some anti-loosening measures to ensure the reliability of the nut locking. The lock nut is one of the anti-loosening measures. The anti-loosening effect of the lock nut mainly depends on the interaction force between the nut and the thread of the bolt. There are many ways to improve the interaction force between meshing threads, such as structural improvement of nut threads, nylon roughening of nylon nuts, and surface treatment of threads.
Usually, the pumped storage unit adjusts the opening of the guide vane through the movable guide vane to control the power generation output and the pumping head of the unit. The torque of the guide vane rotation depends on the relay to act on the control ring, and the torque is transmitted to the guide vane rotating shaft through the connecting rod and the arm. The torque transmission between the crank arm and the rotating shaft all acts on the pin located between them. When the unit is overhauled, it is necessary to remove the pin between the arm and the rotating shaft of the guide vane in advance when it comes to the replacement of the guide vane. However, due to the special position of the pin and the limited inspection space, the conventional method is not only time-consuming and laborious, but also has the risk of damaging the pin. Maintenance work brings inconvenience.
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