What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In order to achieve the above purpose, Guangdong Yueluo Hardware Industry Co., Ltd. provides the following technical solution: a square nut, including a nut body, the nut body is in the shape of a cube, the side length is 7.6mm, the height is 2.4mm, and the nut body is up and down. Both ends are respectively provided with a circular protrusion and a circular protrusion with a height of 0.25mm, the circular protrusion and the circular protrusion are respectively tangent to the upper and lower surfaces of the nut body which are square, and the circular protrusion and the circular protrusion are respectively tangent to the square upper and lower surfaces of the nut body. The protrusion and the circular protrusion are provided with a through hole in the middle and penetrate through the nut body. The opening of the through hole is provided with a chamfer of 30°, and the inner wall of the through hole is provided with a thread. There are several strip-shaped protrusions from the circumference inward to the opening of the through hole, and a number of strip-shaped grooves are arranged from the opening of the through hole outward to the circumference of the circular protrusion. There is a chamfer of 15° extending outward to the prism of the nut body.
Code name and standard number of inch thread commonly used abroad Mark code name country and standard number Remarks BSW standard Wyeth coarse thread series, general purpose cylindrical thread British standard BS 84 inch thread with a profile angle of 55° BSF standard Wyeth fine thread series, General Purpose Cylindrical Thread Whit.S Additional Whit.S Optional Series, General Purpose Cylindrical Thread Whit Non-standard thread with Whitworth profile UN Uniform thread of constant pitch series American standard ANSI B1.1 inch thread with 60° profile angle, with Internal and external threads with standard profile (flat or rounded at random) UNC Coarse thread unified thread UNF fine thread unified thread UNEF superfine thread unified thread UNS① Special series unified thread UNR round The uniform thread profile angle of the arc root constant pitch series is 60° inch thread, UNR, UNRC, UNRF, UNREF, UNRS with arc root are only used for external thread without internal thread UNRC arc root coarse thread Series Unified Thread UNRF Circular Root Fine Thread Series Unified Thread UNREF Circular Root Ultra Fine Thread Series Unified Thread UNRS Circular Root Special Series Unified Thread NPT② Generally used for pipe thread American standard ANSI B1.20.1 Profile angle is 60° Inch Pipe Thread NPSC Pipe Fitting Straight Pipe NPTR Pilot Connection Tapered Pipe NPSM Mechanical Connection Straight Pipe NPSL Lock Nut Straight Pipe NPSH Hose Connection Straight Pipe NPTF Dry Seal Standard Tapered Pipe Thread American Standard ANSI B1.20.3 Type I PTF-SAE SHORT Dry Seal Short Taper Pipe Thread Type II NPSF Dry Seal Standard Fuel Oil Straight Pipe Internal Thread III Type NPS1 Dry Seal Standard General Straight Pipe Internal Thread IV Type ACME③ General Purpose Trapezoid Thread American standard ANSI B1.5 Inch drive thread with 29° profile angle ① Dimensions and tolerances All diameter and pitch combinations other than the standard series are calculated using the same formula as the standard series. ② my country's 60° conical pipe thread GB/T12716-1991 is equivalent to it. ③ACME thread includes two kinds of matching trapezoidal threads, general purpose and centering, of which the general purpose thread has the same performance as the trapezoidal thread specified in my country's standard GB/T5796-1986.
hand screw is a screw with a plastic head, and the user fixes the hand screw by turning the plastic head by hand. At present, a hand-tight screw is disclosed in the market publication number CN202203253U, which includes a plastic head and a screw rod, the plastic head and the screw rod are connected together, and the height of the plastic head is higher than that of an ordinary screw, and the height is 7cm. The screw of the hand screw is fixed in the plastic head by glue. After a period of use, the aging of the glue leads to the loosening of the screw and the plastic head. When the plastic head is stressed, the screw rod comes out of the plastic head, which affects the normal use of the hand screw.
The purpose of Yueluo is to provide a brake pad rivet with shrinkage that can not only solve the problem of normal feeding during assembly, but also save the processing cost of the original machining chamfering and reduce the quality risk of the rivet in use. its production method.
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