Flow control valves

A flow control valve comprising:

• a case defining therein a cylindrical fluid passage;
• a valve body disposed within the fluid passage so as to be capable of axially advancing and retreating, and
• a spring urging the valve body in a retreating direction, wherein:
• the fluid passage includes a cylindrical measurement hole,
• the valve body has an outer circumferential surface including a tapered measurement surface, so that a measurement region is defined between an inner circumferential wall of the measurement hole and the tapered measurement surface of the valve body,
• a flow rate of fluid flowing though the fluid passage is controlled by adjusting a passage sectional area of the measurement region through axial movement of the valve body,
• the valve body includes a front side guide and a rear side guide,
• the front side guide includes a plurality of rib portions protruding radially from the measurement surface of the valve body, and having first sliding surfaces configured to slidably contact the inner circumferential wall of the measurement hole, so that the plurality of rib portions divide the measurement surface into a plurality of measurement surface portions comprising a plurality of stepped, tapered surfaces extending in straight lines in a longitudinal direction along the valve body,
• the rear side guide includes a flange portion formed on a rear end portion of the valve body;
• the flange portion includes a second sliding surface and a cutout surface, the sliding surface slidably contacting a passage wall surface of the fluid passage located on an upstream side of the measurement hole;
• an opening is defined between the cutout surface and the passage wall surface for allowing flow of the fluid;
• the cutout surface includes a reference surface configured as a flat surface and serving as a reference when performing configuration measurement of the measurement surface;
• the measurement surface and the reference surface are arranged such that a diametrical line extending in a radial direction with respect to an axis of the valve body, in a front view of the valve body, intersects each of the measurement surface portions of the measurement surface at a first intersection point, and intersects the reference surface at a second intersection point;
• and
• the second intersection point is positioned radially outward of the first intersection point.