Dependent fittings on the outer and inner surface of the location.They can be internal, external, conical and cylindrical.They differ in cross section and profile parts: round, rectangular, resistant, trapezoidal.The appointment is screwed or mounting.
Mounting has a triangular profile and is divided into two groups: the inch and metric.
inch threaded connection is measured in inches (from this the name), a step is 25.4 mm.It is characterized by the amount of helical thread line one inch cut parts.
Inch are used to connect pipes (called "pipe thread").It is also used for cutting in spare parts of various equipment.The machines, which are produced in our time, inch thread does not apply.The standards developed under the metric, so the design is carried out under the standard.
fitting with buttress thread used for large nagruzkah.Trapetseidalnye are mounting in the transmission of motion (screw driving) and effort, but do not make a hard binding details.For valves used round thread machines it is rarely used.
C triangular profile screw connections are the most reliable, even when the same diameter.Thrust is less strong.Even less credible is trapezoidal thread, weakest - rectangular.Thanks to a smooth rounded in a circular high dynamic strength.
threaded connections are divided into groups: screw, combined, bolted and hairpin.
simple compounds consist of nuts and screws.
to loosening did not occur in the compounds used latching parts that mitigate vibration and shock, reduce friction.
references contained in many ways from self-locking.
threaded connections are made to the vehicle by means of bolts made of a carbon metal.The fasteners that require high reliability and durability, used alloy chrome steel.At the time of tightening, use a dynamic key (it points normalized load force) .Such keys are used in applications where the power connection is strictly defined in the technical documentation.
Threaded connections first clamp, then slightly loosen and re-tighten.So the correct clamping force is controlled.
Calculation of threaded connections is performed to determine the voltage which occurs at the connection.You also need to calculate the margin of safety for the bolts used.
calculation is performed on the elements:
- without nut and nut;
- with loads of eccentric and concentric;
- with fastening pin;
- the contact area determined by the geometry of the thread;
- if a lot of areas of cylindrical shafts;
- with a plurality of plates.
The calculations used some statistical load.
threaded connections are good because they can always be disassembled without damaging the parts themselves.
