What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
In all kinds of machines and equipment, the various parts are fixed and assembled by bolts and nuts. However, after the machine and equipment are used for a period of time, the bolts and nuts will become loose, which will bring great safety hazards to the use of the machine and equipment. For this reason, when bolts and nuts are used for connection, a spring washer is installed between the nut and the connected part. The spring washer is in the shape of a circular ring, and the ring is not closed, and is sleeved on the bolt. The addition of the spring washer has a certain anti-loosening effect, but it can only prevent the nut from rotating relative to the bolt. In the case of large vibration of the machine, the bolt will rotate relative to the connected part.
Generally speaking, the metal plate needs to open holes for inserting the rivets, and then press the two sides of the metal plate along the positive direction of the metal plate with a jig, so that the metal plate is deformed in the plane direction, which makes the inner edge of the hole Shrink and fit the rivet. Existing riveting techniques are not suitable for thin sheets. Because the thin plate does not have enough thickness to compress in its forward direction, the insufficient deformation in the forward direction causes enough deformation in the plane direction to insert the rivet, so the rivet cannot be firmly fixed to the thin plate.
As the preferred embodiment of the above-mentioned embodiment, the motor 41 is provided with a thruster 46 that moves the cutting wheel 42 toward the conveying device 3. When the screw needs to be slotted, the thruster 46 generates a thrust toward the screw, and the motor 41 generates a thrust in the direction of the screw. Under the action, the groove is moved along the track 47 toward the screw. The other end of the motor 41 is provided with a bearing 45, and the output end of the motor is provided with a special-shaped wheel 44. The special-shaped wheel 44 is geared to the bearing 45. The wheel 42 is close to or away from the conveying device 3. When the grooving is completed, the special-shaped wheel 44 rotates and drives the bearing 45 to generate the opposite force from the above-mentioned thrust, so that the motor 41 moves back to the original position along the track 52.
A screw can be equipped with only one spring washer or only one flat washer, or it can also only be equipped with a two-piece combination of flower teeth. The national standard number of the combination screw is represented by GB9074. The commonly used cross recessed small pan head three combination screw national standard is GB9074.8. This .8 refers to the small pan head. That is, the size of the head of the pan head screw that is often said. Denoted by letters as PM. Professional combination screw manufacturers, the habitual expression method is three-in-one PM. The commonly used cross recessed large pan head combination screw national standard is GB9074.4. Professionally called large pan head combination screws. Or R head, or B head. That is to say, the head of this combination screw is larger and thicker than the head of the small pan head combination screw. There is also a commonly used external hexagon combination screw, which is a cross external hexagon combination screw. It is often called a socket hexagon combination screw. The national label is GB9074.13.
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