Cooling-water control valve device

A cooling-water control valve device, which is provided in a cooling system for cooling down a cooling-subject device and controls a flow rate of cooling water to the cooling-subject device, comprising:

• (1) a housing including;
• (1a) a main valve accommodation space;
• (1b) a first opening portion for communicating the main valve accommodation space to the cooling-subject device, so that cooling water flows from the cooling-subject device to the main valve accommodation space through the first opening portion;
• (1c) a fail-safe valve accommodation space;
• (1d) a second opening portion for communicating the fail-safe valve accommodation space to the cooling-subject device, so that the cooling water flows from the cooling-subject device to the fail-safe valve accommodation space;
• (1e) a main water passage to be connected to a main outside component for communicating the main valve accommodation space to the main outside component;
• and
• (1f) a fail-safe water passage for communicating the fail-safe valve accommodation space to the main water passage;
• (2) a main valve unit rotatably provided in the main valve accommodation space, so as to control the flow rate of the cooling water from the first opening portion to the main water passage depending on a rotational position of the main valve unit;
• (3) a fail-safe valve unit provided in the fail-safe valve accommodation space and operated in such a manner that;
• (3a) the fail-safe valve unit is closed when temperature of the cooling water is lower than a predetermined value so as to block off flow of the cooling water from the second opening portion to the fail-safe water passage;
• and
• (3b) the fail-safe valve unit is opened when the temperature of the cooling water is higher than the predetermined value so as to allow the flow of the cooling water from the second opening portion to the fail-safe water passage;
• and
• (4) a partitioning wall formed in the housing for fluidically partitioning each of the first opening portion and the main valve accommodation space respectively from the second opening portion and the fail-safe valve accommodation space;
• wherein
• the housing further includes an inside communication hole for communicating the fail-safe valve accommodation space to the main water passage;
• a valve body of the main valve unit is formed in a cylindrical shape and has a valve communication hole formed in a cylindrical wall portion of the valve body for connecting an inside space to an outside space of the valve body,
• an axial open end of the valve body is connected to the first opening portion, so that the cooling water flows from the cooling-subject device into the inside space of the valve body,
• the valve body is rotatably provided in the main valve accommodation space so as to be rotated about an axis of the valve body,
• an overlapping area between the valve communication hole and the main water passage is changed depending on the rotational position of the main valve unit so as to control the flow rate of the cooling water flowing from the first opening portion to the main water passage, and
• the inside communication hole is formed at a radial-outside position of an inner peripheral wall of the main water passage and at a radial-outside position of a sealing surface, which is formed between the cylindrical wall portion of the valve body and the main water passage, and
• the inside communication hole communicates the fail-safe valve communication space to the main water passage via the valve communication hole, when a part of the valve communication hole overlaps with the main water passage.