On the UG expression of the vacuum pump single head pitch concave rotor design skills

[Asia pump network] Dry-type screw vacuum pump is the use of the screw, in the pump casing for high-speed reverse rotation of the suction compression and exhaust effect of the suction device, the two screws fine dynamic balance correction by the bearing support, Installed in the pump housing, there is a certain gap between the screw and the screw, so the pump work, no friction between each other, smooth operation, low noise, the working chamber without lubricating oil, therefore, A large number of steam and a small amount of dust gas, the ultimate vacuum higher, lower power consumption, with energy saving, maintenance-free advantages. It is a replacement oil seal vacuum pump products. About the UG expression vacuum pump single-headed concave concave rotor design skills Dry-type screw vacuum pump is a very high technological content of technology products, mainly used in high-purity vacuum process, the vacuum is high, can adapt to harsh conditions, with Extraction of condensable, particulate matter-containing gas capabilities, especially suitable for electronic, chemical and biomedical screw rotor is the core part of the screw vacuum pump, the merits of the rotor profile directly affects the overall performance of the pump, the operation of the stable and reliable and manufacturing cost. Single-head pitch trapezoidal concave profile is currently the most commonly used domestic and foreign manufacturers of a type of line, its excellent overall performance, good sealing performance, area utilization factor, and to solve the rotor tooth surface interference problems, it is widely used. Screw rotor belongs to the complex three-dimensional curved surface space entity. It is difficult to generate the model directly by using the three-dimensional software. In this paper, three-dimensional model of the screw is generated by first drawing the screw rotor face profile and then scanning the face profile. For the involute lines and trochoidal lines contained in the face profile, unconventional curves can be drawn using expressions. Screw rod profile of the composition and the type equation involute and cycloid design is often used in the rotor two types of lines. A pair of screw rotor meshing end profile diagram, the main parameters of the center distance a, addendum circle foot radius, radius of the root circle enough to generate a circle radius r., Meshing circle radius ri and screw lead P. Where R + R, = a = 2ri. The rotor's end profile consists of four parts, AB, CD for the two concentric arcs, the radius of the rotor tip radius Rt and root circle radius Rr. Radius of r involute, DA section for the cycloid. The corresponding central angles of AB, BC and CD are ai, a2 and a3, respectively. All angles are in radians. The following is the equation of the type of the rotor. UG Modeling In UG software, expressions are very important concepts and design tools. Each shape parameter and positioning parameter of a feature, curve, and sketch is stored as an expression. Expressions can establish reference relationships between parameters and are an important tool for parametric design. Modifying and updating models is easy by changing the value of an expression. For some of the curves available formula, the use of expression functions can easily make the graphics, which is some common CAD software do not have. ⑴ open NX, create a new file, create two concentric circles, the radius of the tip circle radius Rt = 94.5 and the root circle half ⑵ create a cycloid. Click the tool an expression, enter the following cycloid equation click on the curve of the curve tool bar curve button to generate cycloid. ⑶ create an involute. Click the tool-expression, enter the following involute equation: Click the curve curve tool bar curve button to generate involutes. ffl2UG expression curve generated by the end of the Court 3 line trimming, as shown. Then create a spiral that creates a three-dimensional model of the screw using the sweep feature, and the result is as shown. m5 turn t mesh rubber feeding Fig. Vacuum Conclusion In the standard center distance through UG comes with interference check tool inspection, no interference. Through the motion simulation, observe the rotor meshing rotation, the two screws can keep synchronous reverse rotation, no interference when rotating to any angle, and there is no gap, further verify that the rotor profile equation is correct, as shown. Screw rotor screw core vacuum pump is the key technology core, the rotor profile is more complicated, especially the involute section and the cycloid section. UG expression can be used easily, quickly and accurately to create a screw rotor profile, in line with the requirements of modern enterprise production, of practical significance. (Editor: Huang Nengwen QQ:)