What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
screw suitable for a variety of tools is a single-structure threaded part, including a screw body and a screw head. The outer surface of the screw body is processed with an external thread 1, and the outer side of the screw head is formed by six screw heads. Prismatic, the top surface of each edge of the outer hexagonal prism is a boss, between each boss is an end face groove 4, and the middle of each boss is provided with an end face hole 3; the inner side of the screw head is formed by six screw heads. The side surface 5 forms an inner hexagonal prism hole, and the bottom of the inner hexagonal prism hole is processed with a cross groove 12 .
Due to manufacturing and installation errors, the lamp head and its connecting part of the shadowless lamp will drift, which cannot be positioned at any position. Therefore, in the shadowless lamp, the damping force is usually provided by the damping screw to realize the positioning of the lamp cap and its connecting part. The damping screw needs to be able to provide a suitable damping force. The damping force should not be too small to meet the positioning requirements; at the same time, the damping force should not be too large to make the user feel comfortable when moving the lamp head and its connecting parts. In addition, within the normal life range, after the damping screw is worn, it should also be able to provide sufficient damping force to satisfy the positioning of the lamp cap and its connecting part. The damping screw is tightened by the thread, the top pressure disc spring is deformed, and the disc spring presses the friction end to generate frictional force, thereby providing an effective and lasting damping force. The damping force can be realized by adjusting the screw tightness. For the friction ends, there are certain requirements for wear resistance, certain self-lubrication, certain strength, hardness and toughness. At present, the friction end materials in the industry mainly include metals such as brass and tin bronze; non-metals such as nylon and POM. At present, the main disadvantage of the friction end of the damping screw is that it is easy to produce abnormal noise during the friction process for metal materials. For non-metallic materials, deformation is easy to occur and the strength is insufficient.
Ordinary T-bolts, the bolt head is rectangular, the screw part and the bolt head are T-shaped, and the width of the head is smaller than the width of the opening part of the T-slot, so that the head of the T-bolt can extend from the length of the T-slot. Insert the T-slot into the T-slot at any position in the direction. When the workpiece needs to be fixed, turn the T-bolt 90 degrees so that the length of the head is perpendicular to the T-slot, hook the inside of the opening of the T-slot, and screw it by tightening The nut on the T-bolt threaded rod holds the workpiece in place. The T-bolt of this structure can easily connect the bolt and the base piece quickly, and is widely used, but there are also some shortcomings, due to the contact area between the head of the T-bolt and the inner side of the opening of the T-slot. If it is too small, the frictional resistance is correspondingly small. On the one hand, the bolts are easy to follow the rotation during the process of tightening the nut. Unreliable.
With the popularization of electrical equipment, the door cover that integrates the panel, the controller, the sealing and waterproof function and the appearance decoration has gradually been required for equipment matching. The head directly affects the appearance, and for kitchen equipment such as dishwashers, the fixing screws of the door cover are easily rusted in direct contact with the washing water, which urgently needs a door cover structure that is easy to disassemble but does not affect the appearance.
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