What is the coefficient of gear displacement?
For generating the gear machining tool, midline and gear pitch circle tangent, modification coefficient of gear indexing tool midline and circle distance divided by the quotient is the gear modulus. The cutter center line is in the positive position outside the gear dividing circle, and the deflection coefficient is positive. On the contrary, it is negative.
In order to improve the performance of gear drive, a gear shift has occurred. As shown in the figure, when the rack tooth top line over the limit point of meshing N1, cut out of the gear undercut. If the rack at a distance away from the wheel center O1 (XM), tooth top line no longer exceeds the limit point of N1 gear is not cut out of the undercut, but this time with the dividing line dividing rack gear circle is no longer tangent. When the cutter is in relative position with the gear blank, the cut out gear is called a variable gear, and the distance of the tool moving is called XM, and X is called the displacement coefficient. The shift of the tool away from the center of the wheel is called a positive displacement. At this point, x>0, the tool moves near the center of the wheel and is called a negative displacement. At this point, x<0. A standard gear is a gear whose coefficient of change is x=0.
(2) it is not suitable for installing the center distance A'not equal to the standard center distance a. When a'<a cannot be installed, when a'>a, although can be installed, but will produce too large backlash caused by shock and vibration, affect the stability of transmission; (3) a pair of standard gear tooth thickness, small small gear and the meshing number is more, so the small gear tooth root strength is low. Some wear is more serious, so the small gear is easy to damage, but also limits the capacity of large gear.
Standard gear transmission has some limitations: (1) by undercutting limit, the number of teeth shall not be less than Zmin, the transmission structure is not compact enough;
