空気さく岩機の性能におよぼすバルブ駆動通路口の位置の影響

空気さく岩機の性能に関する基礎的研究 (第3報)

抄録

The positioning effect of the cylinder ports of air-passage-ways to the fore- and rear-chambers in the valve on the performance of an automatic air-rock-drill was studied theoretically and experimentally by making cylinders with the ports positioned near the exhaust port of air.
The results obtained in this study are as follows:
(1) The theoretical results calculated by the proposed theory in this study fairly well coincide with the experimental results obtained on the performance of the above cylinders.
(2)The average velocities of foregoing and returning valves increase linearly with input air pressure independently of the position of the above-mentioned ports in the cylinder. The velocities increase as inner pressure in the cylinder, when its port is open, increases and air in the chamber opposite to a compressed chamber of the valve is exhausted sufficiently.
(3)In case of a constant length of piston and a short interval of the cylinder ports, the valve motion is remarkably affected by the conditions of exhausting air in the valve. Therefore, interrelation of length of piston and diameter of the exhaust port in the valve as well as location of the cylinder ports must be considered when designing an air-rock-drill.
(4)In order to increase the blow-velocity of piston, the time when compressed air gets into each chamber must be delayed in the foregoing and returning process of the piston, reducing the compression ratio of the fore-chamber and increasing the piston-stroke.
(5)For an automatic air-rock-drill, the theoretical design of the drill with better performance could be considered since it is possible to control the time when compressed air enters the fore- and rear-chamber of the cylinder.