What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Screw, some people call it screw [Screw] (screw), screw (screw rod). In fact, the screw is a general term, and the screw and the screw rod are different from each other. Screws are generally called wood screws; they are the ones with a pointed end at the front and a larger pitch. They are generally used to fasten wooden and plastic parts. The screw rod is a machine screw (machine screw), which is the kind of flat head at the front end. The pitch is small and uniform. It is generally used to fasten metal and machine parts.
Screws can be divided into machine screws, self-tapping screws, drill-tail screws, wallboard screws, fiberboard screws, wood screws, hexagonal wood screws, non-prolapse screws, combination screws, miniature screws, furniture screws, and electronic screws. Divided into 1. Hexagon head (hexagon head) 2. Hexagon head with flange (hexagon head with flange) 3. Square head (square head) 4. T head (hammer head) 5. Oblate head mushroom head ( truss head) 6. cylindrical head (cheese head) 7. round head (round head) 8. pan head (pan head) 9. countersunk head (flat head) 10. raised countersunk head (oval according to the groove type) Can be divided into 1. Philip 2. Ten / one word 3. One word 4. Inner triangle 5. Inner corner square 6. Cross 7. Rice word 8. Flower shape 9. Plum shape 10. Flower shape one word 11. Special shape 12. Inside Hexagon
The lifting ring screws are generally not surface treated, but according to the requirements, surface treatment such as galvanized passivation and chrome plating can be carried out, and it is specified in GB5267-85. The chemical composition and mechanical properties of the material should be treated immediately after electro-galvanizing. The test methods are specified in GB699. During routine inspection, the grain size test may not be advanced, and the grain size test method shall be in accordance with the provisions of YB27. Thread inspection is performed with thread gauges and smooth limit gauges or universal energy tools.
Usually, the car wheel is fixed on the axle sleeve with positioning pins and pins, and the tire hub and the sleeve are fastened on the axle with locking nuts, lock washers, and adjusting nuts. This structure can operate normally within a certain period of time when the vehicle speed is low and the vibration is small. However, when the car runs for a long time, especially when the road surface is uneven and the load changes sharply, the axle sleeve bears a great impact. Once the shear force generated is too large, the pin will break, and the nut will be loosened. Affected, the wheel and hub will be loose. If the maintenance is not timely, or the driver is inexperienced, the car will have an accident in which the tire falls off with the wheel hub. This is extremely dangerous. So people are looking for ways to prevent wheels and hubs from falling off
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