| 摘要 |
PROBLEM TO BE SOLVED: To perform an easy and well-stable self-supporting of the cover under its vertical setting state without being dependent upon a jig when a spool hole is machined and inspected.SOLUTION: A valve fixing part 22 is integrally arranged at one surface of a flange part 21 and a spool hole 23 for a counter-balance valve is arranged at the valve fixing part 22. Under assumption of this arrangement, a part of the outer circumference of the flange part 21 is provided with a self-supporting flat surface part 24 acting as a plane surface perpendicular to an axial direction of the spool hole 23 and in turn a drain port 25 is arranged at the valve fixing part 22 under a state in which it is opened in an axial direction of the spool hole 23 at the port opening flat surface part 26 that is on the same flat surface as the self-supporting flat surface part 24, and the center of gravity G of the entire cover is set in an overturn limit area A including both the flat surface parts 24, 26.SELECTED DRAWING: Figure 3 |
