Service HotlineThe national standard name of the cross recessed small pan head three combination screw is the cross recessed small pan head screw, the spring washer and the flat washer assembly. The national label is GB/T9074.8-1988. This 1988 refers to the year, that is, this standard is the standard issued by the country in 1988. The specifications of the cross recessed small pan head three combination screws, the company's minimum is M2.5, the shortest is 5mm, the largest is M10, and the longest is 90mm.
In the prior art, the spring washer has a certain anti-loosening effect. However, due to the unreasonable design structure, the upper and lower pressing forces of the spring washer and the spring washer's anti-return force are poorly matched, resulting in the smooth surface and the bolt head. The friction between the nut and the connected parts is small. When the bolt or nut is subjected to strong vibration, the bolt or nut will still loosen. Therefore, the anti-loosening effect of the above spring washer still needs to be improved.
1. The twisted screw should be considered according to the actual inner diameter of the barrel, and the outer diameter deviation of the new screw should be given according to the normal clearance with the barrel. 2. After the thread surface with the reduced diameter of the worn screw is treated, the wear-resistant tungsten carbide alloy is thermally sprayed, and then ground to size. 3. Surfacing wear-resistant tungsten carbide alloy on the thread part of the worn screw. According to the degree of screw wear, surfacing welding is 1~2mm thick, and then the screw is ground and processed to size. This wear-resistant tungsten carbide alloy is composed of materials such as C, Cr, Vi, Co, W and B, which increases the wear resistance and corrosion resistance of the screw. 4. The bottom diameter of the screw is repaired by electroplating hard chromium. Chromium is also a wear-resistant and corrosion-resistant metal, but the hard chromium layer is easier to fall off.
In the repair process of the EDITION 700 gearbox, it is often necessary to replace the piston seal. When replacing the direct gear piston seal, the shaft spring retaining ring on it must be removed before the piston can be taken out for replacement. For the seal, since the piston return spring 3 presses the retaining ring 5 through the spring seat 4 (as shown in Figure 3), it cannot be taken out directly. It is necessary to press down the spring seat before taking out the retaining ring. Without special tools, it is not easy to remove the retaining ring. At present, it is a time-consuming, labor-intensive and unsafe job that requires multiple people to use a screwdriver and a prying board to forcefully squeeze and pry to remove the retaining ring.
As a special kind of rivet parts, the rivets for shrinking brake pads are used in the accessories of the automobile industry. The original brake pad rivets do not have a chamfered structure, so the materials cannot be normally fed during assembly, or there are burrs, which lead to unqualified batches. When improving this structure, many manufacturers in the same industry often solve the problem by machining chamfering, but for brake pad rivets with thin thickness, it is impossible to achieve the problem of beating and bad material after chamfering processing.
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