What is the bevel gear ratio range?
Bevel gear drive consists of a pair of bevel gears, which is also called bevel gear transmission.
Curve tooth bevel gear and helical bevel gear, helical gear with progressive meshing characteristics of contact, and the coincidence degree is large, therefore, stable transmission, low noise, strong bearing capacity; minimum tooth number can reach 5, which can obtain larger transmission ratio (up to 10) and the smaller size of institutions. But the machining of curve bevel gears is complicated. Curvilinear bevel gears are typically used for vm>5 M / s, and with a gear grinding gear, the VM can be greater than 40 meters per second. This kind of drive is widely used, especially in high speed and heavy duty occasions, such as differential gears for automobiles and machine tools. The curvilinear bevel gears are divided into spiral bevel gears and hypoid bevel gears according to the shape of tooth lines (Figure 3). The spiral bevel gear tooth circular arc line. This kind of gear was first machined on Gleeson's machine tools, so it is also called Gleeson bevel gear (Gleason). Because the tooth line is arc, it is easy to grind the tooth, and can obtain the high precision gear. The cycloidal tooth bevel gear tooth line is epicycloids a section of AB, cutting is continuous rotary gear, a gear as long as the procedure can complete the rough cut and finish cutting processing, higher productivity, but it is not easy to grinding, precision is limited. The angle between the tangent line TT of the tooth width and the midpoint of the tooth line and the pitch cone generatrix is called the spiral angle of the beta M. Generally take beta m=35 degrees to 40 degrees, the most commonly used is 35 degrees. The mating gears have equal helix angles and opposite turns. The spiral gear of the beta m=0 is called the zero bevel gear. The zero bevel gear grinding VM = 50 m / s.. This kind of gear drive can be used instead of the straight bevel gear instead of changing the structure of the support and the box.
Its motion is the same as that of a conical friction wheel, which is made up of a pair of vertices and is made of pure rolling. The friction cone is equal to the taper of the cone gear drive. The angle between the generatrix and the axis is called the pitch cone angle. The angle between the axes of the bevel gear drive = Delta 1+, delta 2, may be determined as required, usually 90 degrees. The transmission ratio is n, Z, D respectively for speed, number of teeth and big gear pitch circle diameter of 1 feet, the subject refers to the ferry, 2 big wheels. When =90 degrees, classification according to the shape of the tooth line, bevel gear drive can be divided into straight teeth, oblique teeth and curvilinear bevel gears, in which straight teeth and curved teeth are widely used. According to the gear teeth at both ends of high variation (Figure 2) bevel gears can be divided into the following 4 types: high tooth, from big to small end tooth height unchanged, commonly used in spiral bevel gear, the gear machining tool and machine tool adjustment is simple; the normal contraction cone teeth. The top point, pitch cone apex and root cone apex three coincident, straight bevel gears in the tooth, but the tooth fillet is small, is not conducive to the tooth root strength and cutting tool life; the top gap shrinkage tooth, root cone top cone and meshing gears are parallel, by end to the small end of the tip clearance is equal; the double shrinkage tooth, cone apex, pitch cone apex and root cone apex are not coincident, and the root cone top cone and meshing gears in parallel. The teeth of the latter two teeth have larger fillet angles, which are often used in spiral bevel gears. Straight bevel gear drive, this kind of transmission has poor stability. It is usually applied to the average pitch speed of vm<5 meters per second. Its carrying capacity is relatively low, but it is more convenient to manufacture, so it is widely used.
