Vehicles such as hybrid automobiles or electric automobiles in many cases include a current detector for detecting a current that flows through a busbar connected to a battery. Examples of apparatuses that may be applied as such a current detector include a magnetic proportion-type current detector and a magnetic balance-type current detector.
A current detector of a magnetic proportion type or a magnetic balance type includes a magnetic core and a magneto-electric conversion element, for example, as shown in JP H10-104279A, JP 2006-166528A, and JP 2009-58451A. The magnetic core is a magnetic material substantially in the shape of a ring with a gap portion, resulting in two ends facing each other across the gap portion, and formed in one piece so as to surround a hole portion penetrated by a busbar. The hole portion of the magnetic material is a space (current detection space) through which a current that is to be detected flows.
Further, in the conventional current detector, the magnetic core has a structure obtained by a plurality of thin plate-like members that each have substantially the shape of a ring and are made from a magnetic material being stacked one on the other via an adhesive agent. Hereinafter, the magnetic core having such a structure is referred to as a stacked-type magnetic core.
The magneto-electric conversion element is disposed in the gap portion of the magnetic core. The magneto-electric conversion element is an element that detects a magnetic flux that changes in accordance with a current that flows through the busbar penetrating the hole portion, and then outputs a detection signal of the magnetic flux as an electrical signal. As the magneto-electric conversion element, typically, a Hall element is used.
In a current detector, the polarity of the detection signal of the magneto-electric conversion element depends on the direction of the current that passes through the hole portion of the magnetic core. For this reason, the current detector needs to be disposed in a proper orientation that is predetermined with respect to the direction of the current flowing through the busbar.
As disclosed in JP 2009-128116A, in current detectors, the magnetic core and the magneto-electric conversion element are often supported in a fixed positional relationship by an insulating casing. The casing positions a plurality of components constituting a current detector in a fixed positional relationship. Note that generally the casing is composed of an insulating resin member.