VALVE DEVICE, COOLING WATER CONTROL UNIT, AND COOLING WATER CIRCUIT

To change a flow rate in a low opening area with a high degree of accuracy.SOLUTION: A valve device 1 comprises a rotating shaft 2, and a valve body 4 within which a space 10 is formed, that is, the valve body 4 that can be rotated around the rotating shaft 2. A first communication hole 36 communicating with the space 10, and a bottomed groove 38 extended in one of rotational directions of the rotating shaft 2 from the first communication hole 36 are formed on an outer peripheral surface 28 of the valve body 4. The groove 38 includes a first section 40 in which at least one of the depth D of the groove 38 and the width W of the groove 38 becomes greater as it gets closer to the first communication hole 36.SELECTED DRAWING: Figure 3 【課題】低開度域における流量を高精度に変化させる。【解決手段】バルブ装置１は、回転軸２と、内部に空間１０が形成される弁体４であって、回転軸２を中心として回転可能な弁体４と、を備え、弁体４の外周面２８には、空間１０と連通する第１連通孔３６、及び、第１連通孔３６から回転軸２の回転方向の一方に向かって延びる有底の溝３８が形成され、溝３８は、第１連通孔３６に近づくにつれて溝３８の深さＤ及び溝３８の幅Ｗのうち少なくとも一方が大きくなる第１区間４０を含む。【選択図】 図３