Service HotlineSubject content and scope of application This technical requirement specifies the technical requirements for the manufacture, installation and inspection of high-strength bolted joints of mobile machinery and equipment. Contents not specified in this technical requirement shall be implemented in accordance with relevant national standards. This technical requirement applies to mobile machinery steel structures that require high-strength bolted connections. This technical requirement applies to quality control and construction methods for in-plant and on-site installations. 2. Joint surface treatment 2.1 For friction type high-strength bolt connections, the joint surfaces at the joints are required to be in close contact with each other and have a sufficient friction coefficient. When the design drawing does not specify the treatment requirements for the joint surface, the treatment shall be carried out according to the following regulations: sandblasting or shot blasting the joint surface of high-strength bolts, remove impurities such as rust and oil stains on the surface, and reach the Sa2.5 standard , the roughness is 50 ~ 75μm, and the friction coefficient shall not be lower than 0.40. When there are regulations in the drawings, follow the regulations in the drawings. 2.2 The friction surface of the treated high-strength bolt connection should take protective measures to prevent contamination with dirt and oil. It is strictly forbidden to make any marks on the friction surface of the high-strength bolt connection. During storage in the factory, or during transportation, to the installation site, special precautions should be taken to prevent contamination of the connection surfaces. The installation unit should pay special attention to protecting the cleanliness and friction surface characteristics of the connecting plate of the high-strength bolt and the connecting surface of the parent body. It is not allowed to use a grinder to grind the connecting surface of the connecting plate and the connecting surface of the parent body. 3 Inspection of the anti-slip coefficient of the friction surface of high-strength bolts The inspection of the anti-slip coefficient should be based on the steel structure manufacturing batch, and each 2000t of a single project is regarded as a manufacturing batch, and those less than 2000t are regarded as a batch. When two or more surface treatment processes are selected, each surface treatment process needs to be inspected. Each batch of three groups of specimens. If the connection is diffused to an external enterprise, each corresponding enterprise shall conduct an anti-slip coefficient test. 3.1 The test piece used for the anti-slip coefficient test should be processed by the factory or the diffusion enterprise. The test piece and the representative steel structure member should be of the same material, produced in the same batch, using the same friction surface treatment process and have the same surface state. And use the same batch of high-strength bolt connection pairs of the same performance level and store them under the same environmental conditions. The anti-slip coefficient test is carried out according to the test method of GB50205 Code for Acceptance of Construction Quality of Steel Structure Engineering. 3.2 The minimum value of the anti-slip coefficient inspection must be equal to or greater than the design specified value. When the above specified values are not met, the friction surface of the component should be reprocessed. The friction surface of the treated component is re-inspected. 4. Connection and installation of friction type high-strength bolts for steel structures 4.1 Preparations before installation 4.2 Select qualified bolts, nuts and washers. The guarantee period for the torque coefficient of the connecting pair is six months from the date of delivery. 4.3 Bolts, nuts and washers in the following cases are unqualified products and are prohibited from being used. a. The source (manufacturer) is unknown; b. The mechanical properties are unknown; c. The torque coefficient k is unknown; d. Defective; e. No performance test report attached; f. Mixed with other batches of bolts; g. Bolts with insufficient length, that is, the bolt head does not show the end face of the nut after tightening. Generally, the length of the end face of the nut to be taken out is 2 to 3 threads. h. The torque coefficient of the connecting pair exceeds the warranty period. Special attention should be paid to waterproofing during transportation and storage. 4.4 Before the construction of the large hexagonal head high-strength bolts, the torque coefficient of the high-strength bolt connection pair should be re-inspected according to the factory approval. Each batch of 8 sets should be re-inspected. Less than or equal to 0.010. The re-inspection method of the torque coefficient shall be carried out in accordance with the provisions of GB50205 Code for Acceptance of Construction Quality of Steel Structure Engineering. The installation of high-strength bolts should be carried out within a short period of time after the test.
Guangdong Yueluo Hardware Industry Co., Ltd. provides a shaft retaining ring in order to solve the above problems. The plan of Guangdong Yueluo Hardware Industry Co., Ltd. is a shaft retaining ring realized in this way, which is composed of a shaft washer, a torsion spring, a positioning pin and a limit pin. It is characterized in that the shaft washer is provided with two symmetrical distribution gaps. a circular ring, and a groove is provided at the vertical notch on one side, and a stepped through hole is provided on the side notch facet of the groove to cooperate with the limit pin, and the two sides of the groove are provided with a through hole and a locating pin Matching; the limit pin is a stepped short shaft. The beneficial effects of Guangdong Yueluo Hardware Industry Co., Ltd. are simple structure, low production cost, convenient and reliable use.
The existing automobile fastener nut is a common nut. After the nut is matched with the bolt, during the tightening or disassembly process, there will be a phenomenon of sliding wire, and the safety factor is relatively low; It is difficult to guarantee, easy to rust, requires frequent inspection and replacement, and increases the cost of using the car, which can no longer meet the needs of the market.
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.
At present, there are many kinds of smart terminals on the market. Due to the reduction of the overall volume of the smart terminal and the more compact internal parts, the nuts are generally made of injection-molded nuts. The traditional injection-molded nuts are directly fixed on the equipment. During the process, it is easy to loosen and fall off, which greatly reduces the service life of the injection nut and brings inconvenience to the use of the mobile terminal.
We have many years of experience in the production and sales of screws, nuts, flat washers, etc. The main products are: alloy steel bolts, steel internal thread pins, nut type nuts, black pin shaft GB882 pin T-shaped flat head pin with hole and other products, we can Provide you with the right fastener solution for you.
