| 摘要 |
PURPOSE:To reduce the working noise without damaging the responsiveness during the operation by forming a groove in the axial direction to communicate a first and a second radial holes in at least either of a guide part or an outer circumferential part of a valve plunger to be brought into slidable contact with the guide part. CONSTITUTION:A valve plunger 17 is guided in a slidably manner in the axial direction by a guide part 6b consisting of an inner circumferential surface of a valve body 6. Grooves 6d in the axial direction are formed at four parts in the circumferential direction of this guide part 6b, and a radial hole 6a and a radial hole 6c which are formed before and after the guide part 6b are communicated with each other. In addition, a first pressure changing passage 24 is constituted by the radial hole 6c and the respective grooves 6d. As a result, sufficient area of the flow passage of the first pressure changing passage 24 can be secured, and flow routes are provided not only on the radial hole 6a side but also on the radial hole 6c side. When a boosting device is operated, the atmosphere is rapidly introduced into a pressure changing chamber D, the responsiveness is improved, and the working noise of flowing the atmosphere is reduced. |
