What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Among them, the pneumatic riveting machine is more commonly used. The pneumatic riveting machine is also equipped with a clamp for assembling the rivet. The existing clamp usually uses two rotating clamps for fastening and assembly, but the rotation easily causes the two clamps to buckle. Misalignment, thus affecting the assembly of the rivet.
The traditional fixture shown in Figure 2 is composed of a hardened support cylinder and a hardened shear bar, and has a simple structure. The cylindrical pin is loaded into the hardened support cylinder, and the shear test is completed by applying an axial load to the hardened shear bar. Since the standard stipulates that the gap between the loading part and the supporting part does not exceed 0.15mm, in order to ensure the matching of the gap during the shear test of the cylindrical pin, the diameter of the cylindrical pin on the cylinder is generally equal to the theoretical cylindrical pin. In practical application, the cylindrical pin is irregular in size after heat treatment. To realize the shear test, the cylindrical pin must be inserted into the hole with the help of external force, which is difficult to install and clamp and takes a long time. If the double-sided shearing is performed, that is If the cylindrical pins need to be installed on both sides, the time is doubled, and the notch of the cylindrical pins cannot be guaranteed to face upwards.
At present, injection molding screws are widely used in various electronic and automotive components, including a body, the middle of which is provided with a through hole 3, the body head 1 has a hexagonal cross-section, and the tail 2 is provided with screw teeth. When in use, the middle through hole 3 of the main body will first put the wire harness, and then fix it by injection molding from the head I, and the threads of the tail 11 should be connected and installed with other components. Because the head I of the main body is hexagonal, the torque provided after injection molding is insufficient. Therefore, after the external thread is installed and connected with other components, the head is prone to slip, the installation is not reliable, and there is no push-pull force, resulting in product failure and increased safety hazards.
The spring washer usually includes a washer body and a raised claw head punched and formed on the washer body. The spring washer is often placed between the bolt head of the bolt and the connected parts, wherein the raised claw head is connected to the part to be connected. The surfaces of the connecting parts are in contact, and the plane on the gasket body, opposite to the lifting direction of the raised claw head, is in contact with the bolt head. After the bolt head is tightened, the elastic reaction force generated by the raised claw head after flattening makes the The screwed threads are pressed tightly, and at the same time, the raised claw head is pressed against the bolt head and the supporting surface of the connected parts, which has the effect of preventing loosening. However, the traditional spring washer is a single-claw type. When tightening, the raised claw head will cause great damage to the surface of the connected parts, so it is not suitable for the anti-loosening treatment of parts with small surface hardness.
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