What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The retaining ring with an open ring structure is a commonly used mechanical part. It has standardized design standards. Its main function is to fasten the ring-shaped parts on the shaft, which can prevent other parts mounted on the shaft from moving. kinds of fasteners. In the prior art, the retaining ring is mainly processed by stamping, which has the following defects: 1. The material utilization rate is low;
The Chinese Patent Application No. 201320368989.2 discloses a pin, which includes a pin body and a cylindrical body part integrally provided with the pin body, a convex tip is provided on the cylindrical body part at one end of the pin body, and the convex The tip is horizontally arranged around the cylindrical body part and protrudes from the surface of the cylindrical body part. The connection between the cylindrical body part and the convex tip is provided with an inclined plane. Although this pin solves the problems of easy loosening and falling off to a certain extent, However, this kind of pin still has the problem of loosening and falling off in the case of bad working conditions and severe vibration.
At present, the nut is used as the main body through the riveting connection with the gasket, which is more and more widely used in the industrial field, especially the automobile industry. The gasket connected with the nut has two types: spring gasket and flat gasket. After the nut is tightened, the washer gives the nut an elastic force, which is pressed against the nut to make it not easy to fall off; and the function of the flat washer is to increase the contact area between the nut and the coupling, increase the friction force, reduce the pressure per unit area and protect the surface of the connected parts. Not damaged, stop the nut from loosening. Therefore, gaskets have a wide range of applications in the field of fastening connections, and it is more and more important to improve production efficiency, reduce production costs, and meet growing demands.
China is the world's largest producer of carbon steel fasteners such as screws, nuts and bolts, and the EU is a major market for these products. In January 2009, the EU decided to impose anti-dumping duties of 26.5% to 85% on Chinese carbon steel fastener products. On July 31 of the same year, China resorted to the relevant EU legislation and anti-dumping measures to the WTO dispute settlement mechanism. The case became China's first lawsuit against the EU at the WTO. On July 15, 2011, the WTO Appellate Body issued a report and finally ruled that China won the case in the trade dispute with the European Union on fasteners. The head of the Department of Treaty and Law of the Ministry of Commerce of China welcomed the ruling on the 16th, and said that China's victory in the case is of great significance, which will help improve the competitive environment for Chinese companies in the international market including the European Union, and will also strengthen the WTO members' interest in the case. Confidence in WTO rules and the multilateral trading system. This is not only a victory for China's industry, but also a victory for WTO rules, the official said. The WTO Appellate Body found in its ruling report issued on the 15th that Article 9(5) of the EU's Basic Anti-dumping Regulations on individual tax rates violated WTO rules; at the same time, the Appellate Body overturned some of the panel's rulings and supported China's position , ruled that the EU's anti-dumping measures against Chinese screws, nuts, bolts and other carbon steel fasteners also violated WTO rules in terms of domestic industry identification, normal value and fair comparison of export prices. The head of the Treaty and Law Department of the Ministry of Commerce of China said that the EU is one of the WTO members that has initiated the most anti-dumping investigations against Chinese products in the world. unfair treatment. He said that China hopes that the EU will cancel the legislation and discriminatory anti-dumping measures that are inconsistent with WTO rules as soon as possible, treat Chinese export enterprises fairly, and effectively safeguard free trade and fair competition.
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