Reactor

A reactor comprising:

• a coil having a wound portion;
• a magnetic core that includes an inner core portion arranged inside of the wound portion and an outer core portion arranged outside of the wound portion;
• and
• a resin molded portion including an inner resin portion that fills at least a portion between the wound portion and the inner core portion and an outer resin portion that covers at least a portion of the outer core portion,
• wherein an interval between the wound portion and the inner core portion differs in a peripheral direction of the wound portion, the interval including a narrowest interval and a widest interval,
• the reactor includes an electrically insulating material that is interposed in a location at which narrowest interval t1, and the widest interval t2 to form a portion of the inner resin portion, and
• wherein a thermal conductivity of the electrically insulating material at the narrowest interval t1 is λ1, and the proportion of the interval t1 with respect to the thermal conductivity λ1 is (interval t1/thermal conductivity λ1), and
• wherein a thermal conductivity of the electrically insulating material at the widest interval t2 is λ2, and the proportion of the interval t2 with respect to the thermal conductivity λ2 is (interval t2/thermal conductivity λ2), wherein
• (interval t1/thermal conductivity λ1)<(interval t2/thermal conductivity λ2) is satisfied.