What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The semicircular key is a kind of key, the upper surface is a plane, the lower surface is a semicircular arc surface, the two sides are parallel, commonly known as the crescent key. It is basically the same as the flat key connection method, but it is more convenient to manufacture and disassemble than the flat key, and is especially suitable for the connection between the tapered shaft and the hub. The half-round key transmits torque on the side, but the keyway is deep, which weakens the shaft greatly. Due to the deep keyway, the bottom of the keyway is easily deformed after the shaft is heat treated. Therefore, when the semicircular key and the keyway are assembled in a transitional fit relationship, the interference between the lower part of the semicircular key and the bottom of the keyway often occurs, resulting in difficult or impossible assembly. Assembly situation. In order to solve the above technical problems, the current method is to make the thickness of the semicircular key appropriately thin, so that the semicircular key and the keyway are clearance fit, which brings about a large gap between the upper part of the semicircular key and the keyway, and the semicircular key is in operation. Difficult to locate in the keyway, affecting smooth transmission.
The spring screw is a tool that uses the physical and mathematical principles of the oblique circular rotation of the object and the frictional force to fasten the machine parts step by step; the screw is a common invention in people's production and life for thousands of years. According to the application field, Screws have a wide range of applications.
Nuts and washers are both small and medium-sized components of the tension reinforcement system, and they are easily lost on the construction site when used separately, which is not conducive to the storage management of turnover materials; 3) During the process of formwork support and removal, they must be installed individually And demolition, thus adding a construction process, affecting the efficiency of construction.
Anchor bolts are also known as stiffened anchor plate anchor bolts, welded anchor bolts, anchor claw anchor bolts, rib plate anchor bolts, anchor bolts, anchor screws, anchor wires, etc. It is specially designed to be buried in the concrete foundation and used as the base for fixing various machines and equipment. Figure 7 anchor bolts are the most commonly used anchor bolts. It is generally made of Q235 steel, with high strength using Q345B or 16Mn material, and also using 40Cr material to process 8.8-strength products, and occasionally using secondary or tertiary rebar. Anchor bolts are divided into wool, thick rod and thin rod. The wool material is the raw material steel, which is directly processed from round steel or wire without modification; thick rods or called A-type, thin rods or B-type, are processed from steel modified into the corresponding required rod diameter. Welded anchor bolts are made of single-headed bolts welded with stiffened iron plates. Its anti-pulling ability is strong. According to the different conditions of use, it can reach 3.6, 4.8, 6.8, 8.8 and other grades respectively. The tensile capacity of 3.6 grade 7-shaped anchor bolts is the tensile capacity of the steel itself. The tensile strength of anchor bolts directly processed from Q345B or 16Mn raw materials can reach a tensile strength of 5.8. The tensile strength of grades 4.8, 5.8, 6.8 and 8.8 refer to the provisions on mechanical properties in GB/T3098.1.
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