| 摘要 |
PURPOSE:To provide an apparatus for controlling the opening of a valve by the balance of a spring means and control vacuum, which is capable of obtaining stable flow characteristics, by using two springs imparted with different set loads as said srping means, and thereby obtaining stepwise load-deflection characteristics. CONSTITUTION:An EGR control valve 10 is constituted by connecting a valve element 15 to a diaphragm 13 defining a vacuum chamber 11 and an atmospheric pressure chamber 12 by the intermediary of a connecting rod 14. In the vacuum chamber 11, a spring retainer 20 is fitted on a rod 19 with a stopper 19a fixed to a fixed wall 18 of the vacuum chamber 11, in the manner that it is freely slidable along the axis of the pin 19. Further, compression coil springs 21, 22 are interposed respectively between the fixed wall 18 and the retainer 20 and between the retainer 20 and the diaphragm 13. Here, the set load of a first spring 21 is selected to be greater than that of a second spring 22. With such an arrangement, it is enabled to obtain stepwise valve opening characteristics to a control vacuum signal. |
