Thread is: on the surface of a cylinder or cone, a spiral linear shape, with a specific cross-section of continuous convex parts.
The thread is divided into cylindrical thread and taper thread according to its parent shape;
According to its position in the mother is divided into external thread, internal thread, according to its section shape (tooth type) is divided into triangle thread, rectangular thread, trapezoid thread, serrated thread and other special shape thread.
Measuring method:
① Measurement of the Angle of thread
The Angle between the threads is also called the Angle of the teeth.
The Angle of the thread can be measured by measuring the side Angle, which is the Angle between the side of the thread and the vertical face of the thread axis.
The approximate contour of the thread teeth is sampled in the linear section on both sides of the thread, and the sampling points are fitted by linear least squares.
② Measurement of pitch
Pitch refers to the distance between a point on the thread and the corresponding point on the adjacent thread teeth. Measurement must be parallel to the thread axis.
③ Measurement of thread diameter
The middle diameter of the thread is the distance of the middle diameter line perpendicular to the axis, and the middle diameter line is an imaginary line.
Main uses of thread:
1. mechanical connection and fixing
Thread is a kind of mechanical connection element, which can realize the connection and fixing of parts easily and quickly through the coordination of thread. Commonly used thread connection has two types of internal thread and external thread, internal thread is often used for the connection of parts, and external thread is often used for the connection between parts.
2. adjust the device
The thread can also be used as an adjustment device, for example, the nut can adjust the length of the lever to achieve the purpose of adjusting the length of the rod, to achieve accurate adjustment between the machine components.
3. Transfer power
The thread can also be used as a component for transmitting power, such as a screw drive mechanism. In the field of mechanical manufacturing, the commonly used spiral transmission devices are threaded gear, worm gear and worm drive, lead screw drive, etc. These devices convert rotational motion into linear motion or linear motion into rotational motion through the working principle of the helix.
4. Measurement and control
Threads can also be used for measurement and control. For example, spiral micrometer is a common measuring device, usually used to measure length, thickness, depth, diameter and other physical quantities. In addition, threads can also be used to adjust and control the mechanical position of precision equipment such as electronic components and optical instruments.
In short, the main use of threads is in the field of mechanical manufacturing, electronics, optics, etc., to achieve the connection, adjustment, transmission, measurement and control functions between parts. Whether in the field of mechanical manufacturing or other fields, the thread is an important mechanical component.
Post time: May-11-2024