What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
1. The expansion phenomenon of the spring washer is generally not the problem of the spring washer itself. 2. The spring washer with the expansion ring must be subjected to a radial external tension. The external tension is derived from the tightening axial force generated by the tightening torque. The chamfer creates a radial component of the axial clamping force, which expands the opening of the spring washer. The smaller the chamfer diameter, the greater the possibility of ring expansion. 4. Adding a flat washer between the nut and the spring washer helps to slow down or prevent the expansion of the ring, but the flat washer is too thin or too soft. Prevent ring expansion 5. The reason for the hydrogen embrittlement fracture of spring washers is generally due to unreasonable heat treatment process and the failure of hydrogen removal treatment after electro-galvanizing. A large number of tests and long-term practical experience have confirmed the above analysis.
In the prior art, the independent pocketed spring is to encapsulate the springs in bags independently, connect each independent pocketed spring side by side, and then cover it with a large non-woven fabric to form a Spring cushions. This spring mat structure has many disadvantages: 1. Uneven force and low hardness; 2. Easy to deform, pit, low flatness and unsightly; 3. The spring directly contacts the non-woven fabric, causing wear and tear, and the life of the spring mat relatively short.
The flat key is a key that relies on the two sides as the working surface and transmits the torque by the extrusion of the key and the side of the keyway, and is mostly installed on the shaft. If the flat key is used for a long time or is in a bad working environment for a long time, dust, oil, etc. will inevitably be stuck between the flat key and the keyway. Since the flat key has no ejector threaded hole for disassembly, it is difficult to dismantle, and during the disassembly process A little carelessness will cause damage to the flat key.
In addition, in the prior art, rivets are also used to riveted screws on metal plates. The rivets are nail-shaped objects with a cap at one end. In riveting, the riveted parts are connected by their own deformation or interference. When using rivets, it is necessary to set moderately sized positioning holes in the corresponding positions of the two metal plates, and the rivets directly penetrate into the positioning holes and then riveted. Because this riveting method does not require welding, it will leave a hole on the back of the metal plate. Therefore, in the prior art, the surfaces of the two metal plates after riveting are covered with a layer of smooth metal skin to cover the riveting marks, which will also increase the overall cost, including metal The cost of the skin and the increase in the manufacturing process, while the riveting process is limited, the connection between all metal plates cannot be universal.
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