What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The utility model proposes an installation structure which adopts a T-shaped bolt to cooperate with a channel, which includes a bolt head, an installation channel, a nut and a washer. The upper end of the screw rod is provided with a screw head, the two side walls of the bolt head are respectively provided with an arc surface, the two ends of the bolt head are provided with protrusions, and the interior of the installation channel is provided with an inner cavity, There is an opening above the installation channel, the bolt head is installed in the inner cavity, the nut is installed on the screw, the nut is located above the installation channel, and the gasket is installed on the installation channel and the nut between.
new type of screw includes a fixing object and a screw body composed of a nut, a fixing piece and a screw rod. An outer gear ring is fixedly sleeved on the fixing piece, and a support plate is arranged on the lower side of the outer gear ring. The upper side of the support plate is connected with a mounting frame through an adjustment mechanism, the inside of the mounting frame is connected with the outer gear ring through an anti-drop mechanism, and a mounting plate is fixedly connected to the side of the support plate close to the fixed object, and the mounting plate is clamped The coupling mechanism is connected to the fixture.
In the manufacture of fasteners, the correct selection of fastener materials is an important part, because the performance of fasteners is closely related to its materials. If the material is improperly or incorrectly selected, the performance may not meet the requirements, the service life may be shortened, or even accidents or processing difficulties may occur, and the manufacturing cost will be high. Therefore, the selection of fastener materials is a very important link. Cold heading steel is a steel for fasteners with high interchangeability produced by cold heading forming process. Because it is formed by metal plastic processing at room temperature, each part has a large amount of deformation and a high deformation speed. Therefore, the performance requirements of cold heading steel raw materials are very strict. On the basis of long-term production practice and user research, combined with GB/T6478-2001 Technical Conditions for Cold Heading and Cold Extrusion Steel GB/T699-1999 High-Quality Carbon Structural Steel and target JISG3507-1991 Cold Heading Characteristics of Carbon Steel Wire Rod for Steel, taking the material requirements of grade 8.8 and grade 9.8 bolts and screws as an example, the determination of various chemical elements. If the C content is too high, the cold formability will be reduced; if it is too low, the mechanical properties of the parts cannot be met, so it is set at 0.25% - 0.55%. Mn can improve the permeability of steel, but adding too much will strengthen the matrix structure and affect the cold forming performance; when the part is quenched and tempered, it has the tendency to promote the growth of austenite grains, so it should be appropriately improved on the basis of international standards. 0.45 % - 0.80 %. Si can strengthen the ferrite and reduce the cold formability. SP is an impurity element, and their existence will cause segregation along the grain boundary, resulting in the embrittlement of the grain boundary and damage to the mechanical properties of the steel. It should be reduced as much as possible. B. The maximum value of boron content is 0.005%, because although boron element can significantly improve the permeability of steel, it will also increase the brittleness of steel. Excessive boron content is very unfavorable for workpieces such as bolts, screws and studs that require good comprehensive mechanical properties.
Installation method broadcast 1. One-time burying method: When pouring concrete, bury the anchor bolts. When the high tower is controlled by overturning, the anchor bolt should be buried once. 2. Reserved hole method: The equipment is in place, the holes are cleaned, the anchor bolts are placed in the holes, the equipment is positioned and aligned, and then poured with non-shrinkage fine stone concrete that is one level higher than the original foundation, and compacted and compacted. . The distance from the center of the anchor bolt once buried to the edge of the foundation should not be less than 2d (d is the diameter of the anchor bolt), and should not be less than 15mm (d≤20, it should not be less than 10mm), not less than half the width of the anchor plate Add 50mm, when the above requirements cannot be met, appropriate measures should be taken to strengthen it. The diameter of the anchor bolts used for the structure should not be less than 20mm. When subjected to earthquake action, double nuts should be used for fixing, or other measures to effectively prevent loosening should be adopted, but the anchorage length of anchor bolts should be increased by 5d compared with the anchorage length of non-seismic action. Installation planning of anchor bolts Treatment of anchor bolts loose in the foundation When the anchor bolts are tightened, the bolts may be pulled out. At this time, the bolts should be adjusted to their original positions, and the foundation around the bolts should be shoveled out enough. , and then weld two U-shaped steel bars vertically and horizontally on the bolts, and finally clean the pit with water and grouting, and then tighten the live anchor bolts after the concrete has solidified to the design strength. The treatment method of the live anchor bolt deviation is roughly the same as the dead ground. The method for the anchor bolts is the same, except that the anchor bolts can be pulled out for processing. If the bolt is too long, a section of the thread can be cut off on the machine tool; if the bolt is too short, it can be extended by hot forging; if the position is inconsistent, it can be corrected by bending. Application industry: suitable for various equipment fixing, steel structure foundation embedded parts, street lights, traffic signs, pump, boiler installation, heavy equipment embedded fixing, etc.
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