| 摘要 |
A hydraulic pressure source includes an oil tank for storing hydraulic oil, a hydraulic pump, a motor for driving this hydraulic pump, and an inverter for changing a rotational frequency of the motor. A pipe line for drawing the hydraulic oil from the oil tank by operation of the hydraulic pump branches to a supply pipe line for supplying the hydraulic oil to the hydraulic cylinder, and a release pipe line for releasing superfluous hydraulic oil into the oil tank. The release pipe line has arranged thereon a pressure regulating mechanism and a flowmeter which measures a flow rate of the hydraulic oil flowing into the release pipe line. Based on a measurement value of the flowmeter, the inverter is operable to change the rotational frequency of the motor to become a necessary minimum rotational frequency. |
| 主权项 |
1. A material testing machine for conducting a material testing by applying a testing force to a test specimen, the machine comprising a hydraulic cylinder, a hydraulic pressure source for supplying hydraulic oil to the hydraulic cylinder, and a flow control valve for controlling flow rates of the hydraulic oil which flows into the hydraulic cylinder and out of the hydraulic cylinder; wherein
the hydraulic pressure source includes: a pump for feeding the hydraulic oil in a tank to the hydraulic cylinder; a motor for driving the pump; an inverter connected to the motor for changing a rotational frequency of the motor; a release pipe line having mounted thereon a pressure regulating mechanism for regulating a pressure in a hydraulic circuit, the release pipe line branching from a pipe line which supplies the hydraulic oil from the tank through the pump to the hydraulic cylinder, for releasing a superfluous part of the hydraulic oil discharged from the pump; a flowmeter mounted on the release pipe line for measuring a flow rate of the hydraulic oil flowing into the release pipe line; and a controller for controlling the rotational frequency of the motor through the inverter based on a measurement value of the flowmeter. |
