What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Aiming at the shortcomings of the above-mentioned cabinets in the prior art that are assembled through hardware accessories, which affects the overall appearance, Yueluo provides a cabinet with a hidden screw-type installation structure and an assembling method thereof. The plate is fixed so that the screws can be hidden from the outside.
The surfaces of the existing door panels are spliced together by fasteners such as nails and bolts. For example, a door body structure for a production line disclosed in CN203807555 is used for the doors of each chamber of the coating production line. The size of the mechanism is the same, and the left and right sides of the door body can be freely opened and closed; the chamber door and the door frame are detachably connected by multiple sets of sealing components, and the sealing components include hinge devices and locking parts.
The standard specifies hexagon head bolts with thread specifications of M3~M64, grades A and B. Grade A is used for bolts with D<=24 and L<=10D or L<=150mm (whichever is smaller); grade B is used for bolts D > 24 or L > 10 D or L > 150 (according to the smaller value) bolt size specification mark: thread specification D = M12, nominal length L = 80mm, performance level is 8.8, the table is the same as oxidation, A level Hexagon head bolt tag example bolt GB / T5782-86-M12 × 80 national standard common hex bolt head on the side size and cooperation national standard wrench thread diameter \ pair of edge sidewalls Skin wrench Wrench Double-ended open-end wrench Double-ended Torx wrench. The outer hexagon bolt is the most frequently used type of bolts. The main function of the external thread it has is to cooperate with the nut. Using this threaded connection method, the two parts are integrated. Grade C hexagon bolts are mainly used in steel structure machinery and equipment with relatively rough surface and low precision requirements. Grade A and Grade B hexagon bolts are mainly used in machinery and equipment with smooth surface and high precision requirements. Most of the stainless steel outer hexagon screws are full-tooth and hexagonal head full-tooth bolts. Standard: DIN933, GB5783, ISO4017, ANSIB18. 2.1, JISB1180; non-full thread bolt standards DIN931, GB5782, ISO4014, ANSIB18.2.1, JISB1180.
5. After the closing value material and the geometric parameters of the nut are determined, the change of the closing value has an important influence on the repeated use characteristics of the lock nut. When the closing value becomes larger, the deformation of the threaded piece increases, the strain of the threaded piece increases, the strain cycle hardening phenomenon intensifies, and the pressure FN of the threaded piece increases, which has a tendency to increase the unscrewing torque; on the other hand, the width of the threaded piece decreases. , the total area of the threaded piece decreases, the friction with the bolt decreases, the strain of the threaded piece increases, the low-cycle fatigue performance decreases, and the maximum unscrewing torque tends to decrease. Under the combined action of various factors, the change of the maximum unscrewing torque with the number of repeated uses is difficult to predict, and it can only be observed through experiments.
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