| 摘要 |
PURPOSE:To shorten the gear cutting and key groove machining process and stabilize the quantity by machining a pair of timing gears with high timing precision invariably by use of the same arbor and maintaining the relative angle relationship between key grooves and teeth constant at all times. CONSTITUTION:A gear blank 1 is in a state that a shaft hole 2 is provided on a hub 9 and key grooves 3 machined in advance. Next, in order to get the timing 90 deg. out of phase for the rotor of a two-lobe root-type compressor, alpha=90 deg., n= 0, Z=40 are set for simplicity. According to an equation theta=alpha+180/Z+360n/Z, theta=94.5 deg. is obtained. A pair of key grooves 5, 5' having angular positions displaced each other by this angle are machined on an arbor 4. Next, a pair of blanks 1 is coupled with the arbor 4 at a preset angle theta with individual key grooves 3 being engaged with key grooves 5, 5' of the arbor 4 by use of keys 8 respectively. Then, the arbor 4 is fitted to a gear cutting device and machined for gear cutting, and gears 10, 10' are removed and fitted to shafts 15, 15 of a compressor. |
