| 摘要 |
<p>PURPOSE:To reduce pressure pulsation in a pipe line, and to reduce vibration and noise by providing an oil passage, whose sectional area and length are variable according to a rotational speed of a pump, in an accumulator connecting means connecting the accumulator to the pipe line. CONSTITUTION:A pressure pulsation reducing device 21 is provided for reducing pressure pulsation generated in a discharge pipe line 23 connected to a pump 22, and has an accumulator 24, a rotation sensor 25, a change-over valve 26 and a controller 27. In the change-over valve 26, there are formed a large diameter oil inlet passage 8, a small diameter oil inlet passage 39 having a diameter smaller than the pressure 38, a valve inlet oil passage 40 and oil chambers 41 to 44. When a solenoid 37 is magnetized by supplying current from the controller 27, the valve inlet oil passage 40 is communicated with the large diameter inlet oil passage 38 because a plunger 36 is pressed against a spool 34. When the solenoid 37 is not magnetized, the valve inlet oil passage 40 is communicated with the small diameter inlet oil passage 39. Thus, the solenoid 37 is controlled so as to be magnetized by means of the controller 27 according to the result detected by the rotation sensor 25 in the case where the detected rotational speed is beyond a required range, and is demagnetized in the case where the detected speed is within the required range.</p> |
