Install Checkpoint Gaia Virtualbox Images here. Select the suitable module and its corresponding pitch from the following AGMA specified table: Module m (in MM) - Pitch P (in MM) 2 -6.238 2.5 - 7.854 3.15 - 9.And, we have to find out the Module (m), Pitch (P), Number of helix of Worm (T1), Number of teeth of Gear (T2), Pitch circle diameter of Worm (D1), Pitch circle diameter of Gear (D2), Centre to centre distance(C).Now, let’s say we have the following design input: Speed of the Worm (N1) = 20 RPM Speed of the Gear (N2) = 4 RPM.Also, the module of the worm as well as the gear must be equal for a mating worm and gear.We will use the term Pitch (P) for both the pitch in this tutorial. The axial pitch of the worm and the circular pitch of the gear must be same for a mating worm and gear.Design calculations of the other aspects of the worm gear will be discussed in a subsequent part of the tutorial. We will use the AGMA formulae for doing the calculations. Look at the picture below: Where, D1 – Pitch Diameter of Worm D2 – Pitch Diameter of Gear C – Centre to Centre Distance between the Worm and the Gear This worm gear design tutorial will discuss up to the selection of the module and pitch and the calculation of the number of teeth, pitch circle diameter and centre to centre distance between the worm and gear. Ü Assume Z 1 depending upon the number of stat.ģ.A box must contain a worm and a mating gear (helical gear) and normally the axis of the worm is perpendicular to the axis of the gear. We know that linear velocity of the worm, Mathematically, velocity ratio,ĭG = Pitch circle diameter of the worm gear. to the speed of the worm gear (NG) in r.p.m. Velocity ratio. It is the ratio of the speed of worm (NW) in r.p.m. These two angles are equal for a 90° shaft angle.ħ. Thus, it is usual to specify the lead angle (λ) on the worm and helix angle (αG) on the worm gear. It may be noted that the helix angle on the worm is generally quite large and that on the worm gear is very small. The worm helix angle is the complement of It is the angle between the tangent to the thread helix on the pitch cylinder and the axis of the worm. In case of a worm having multiple start threads, the term normal lead (l N) is used, such thatĦ. The term normal pitch is used for a worm having single start threads. It is the distance measured along the normal to the threads between two corresponding points on two adjacent threads of the worm. Tooth pressure angle. It is measured in a plane containing the axis of the worm and is equal to one-half the thread profile angle as shown in Fig. Halsey that a lead angle less than 9° results in rapid wear and the safe value of λ is 12½°.Ĥ. The lead angle (λ) may vary from 9° to 45°. It is denoted by λ.Ī little consideration will show that if one complete turn of a worm thread be imagined to be unwound from the body of the worm, it will form an inclined plane whose base is equal to the pitch circumference of the worm and altitude equal to lead of the worm. It is the angle between the tangent to the thread helix on the pitch cylinder and the plane normal to the axis of the worm. For single start threads, lead is equal to the axial pitch, but for multiple start threads, lead is equal to the product of axial pitch and number of starts. It is the linear distance through which a point on a thread moves ahead in one revolution of the worm.
WORM GEAR DESIGN CALCULATION PC
It may be noted that the axial pitch (pa) of a worm is equal to the circular pitch ( pc ) of the mating worm gear, when the shafts are at right angles.Ģ. parallel to the axis of worm) from a point on one thread to the corresponding point on the adjacent thread on the worm, as shown in Fig. It is the distance measured axially (i.e. It is also known as linear pitch of a worm. The following terms, in connection with the worm gearing, are important from the subject point of view :ġ.
0 kommentar(er)
