Method for improving fatigue strength of bolt through combination of bolt and connecting piece material

A fatigue strength and connector technology, applied in the field of mechanical parts, can solve the problems of large incomplete contact, easily damaged bolts and nuts, fatigue strength reduction, etc., to increase fatigue strength, firm connection force, and enhance the ability to withstand stress. Effect

Inactive Publication Date: 2009-11-11
孙中强
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002]At present, bolts are used in various mechanical equipment, iron bridges, buildings, construction equipment, various transportation machinery, electrical appliances, glasses and other movable parts or places subject to external vibration The joints of components are widely used. Most of these bolts and connecting parts (nuts) are made of materials with the same hardness. When the bolts and nuts are used together, only 1% of the interior is in contact, resulting in the concentration of tensile stress and tensile stress. The thread of the thread pulls to both sides, while the thread of the nut squeezes inward, the pressure on the bolt and nut increases, and it is easy to be damaged. The larger the size, the more serious the degree of incomplete contact, the lower the fatigue strength, and the easier it is to damage the bolt and nut. How to change this a situation is necessary

Method used

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  • Method for improving fatigue strength of bolt through combination of bolt and connecting piece material
  • Method for improving fatigue strength of bolt through combination of bolt and connecting piece material
  • Method for improving fatigue strength of bolt through combination of bolt and connecting piece material

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Embodiment 1: as figure 1 , 2 as shown,

[0014] The bolt includes a bolt head 1, a bolt cylindrical part 2 and a threaded part 4. The threaded part 4 is composed of an incomplete threaded part 3, a thread tooth removal part 5 and a complete threaded part. The threaded part is obliquely removed from the root of the thread. Part of the frustum-shaped thread removal part 5 is formed. From the minimum diameter of the frustum-shaped thread part to the cylindrical part, the diameter is slowly expanded in an arc shape to form an incomplete thread part 3. The cylindrical part of the bolt is selected according to the thickness of the connected body. When the bolt is screwed with the nut, in order to adjust the nut to the best position, a gasket can be used if necessary to obtain a good screwed state. At this time, the nut is usually 50%-80% of the total length of the bolt. The frustum-shaped thread removal portion 5 is screwed together.

[0015] Comparison results of materia...

example 2

[0019] Example 2: The bolt includes a bolt head 1, a bolt cylindrical part 2 and a threaded part 4. The threaded part 4 is composed of an incomplete threaded part 3, a thread tooth removal part 5 and a complete threaded part. The threaded part is obliquely removed from the root of the thread One part, this part forms a frustum-shaped thread removal part 5, and slowly expands in an arc shape from the smallest diameter of the frustum-shaped thread part to the cylindrical part to form an incomplete thread part 3. The bolt is selected according to the thickness of the connected body When the bolt is screwed with the nut, in order to adjust the nut to the best position, a gasket can be used if necessary to obtain a good screwed state. At this time, the nut usually takes 50%-80% of the total length % is screwed with the frustum-shaped thread removal portion 5 of the bolt.

[0020] Comparison results of material hardness of bolts and nuts, see the table below

[0021]

[0022] Th...

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PUM

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Abstract

The invention relates to a method for improving fatigue strength of a bolt through combination of the bolt and a connecting piece material, which belongs to the technical field of machine parts. The method uses a connecting piece and the bolt which consists of a bolt head, a bolt cylindrical part, an incomplete threaded part, a thread tooth removing part and a complete threaded part, wherein if the hardness of a bolt material is Hb, the hardness Hn of the material of a nut of the connecting piece is equal to (0.4-0.9)Hb. The bolt and the nut are combined by selecting different materials and the hardness of the nut is less than that of the bolt so that the contact surface is enlarged to reduce the stress concentration in the process of matching, the capacity of threads of the bolt to bearing stress is strengthened, thus the bolt is not easy to be damaged, the connection is firmer, and the fatigue strength is improved.

Description

technical field [0001] The invention belongs to the technical field of mechanical parts, in particular to a method for improving the fatigue strength of bolts through the material combination of bolts and connectors. Background technique [0002] At present, bolts are widely used in various mechanical equipment, iron bridges, buildings, construction equipment, various transportation machinery, electrical appliances, glasses and other movable parts or joints of components subjected to external vibrations. These bolts and connectors (nuts) Most of them use materials with the same hardness. When the bolts and nuts are used together, only 1% of the interior is in contact, resulting in the concentration of tensile stress and tensile stress. The thread of the bolt is pulled to both sides, while the thread of the nut is squeezed inward. The pressure on the bolts and nuts increases and they are easily damaged. The larger the size, the more serious the degree of incomplete contact, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F16B35/04F16B31/06F16B33/02
Inventor 西田新一孙中强
Owner 孙中强
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