Current Sensors

Abstract

The current sensor of the present invention comprises: a bus bar through which a measured current flows; a nut used for contact and fixing the bus bar with an external terminal; a magnetic sensor capable of detecting a magnetic field generated by current flowing through the bus bar; a shell component having a storage portion capable of accommodating the magnetic sensor and sealing the bus bar and the nut; and a cover component configured to cover the storage portion; the shell component having an open portion through which a portion of the nut is exposed; the open portion is covered by an insulating protective component; thereby, it is possible to prevent cutting powder generated when a bolt used to fix the external terminal is screwed into the nut and falls to the outside of the current sensor.

Description

Technical Field

[0001] The present invention relates to a current sensor for detecting a current to be measured based on a magnetic field generated by the current to be measured flowing through a bus bar. Background Art

[0002] The current sensor described in Patent Document 1 comprises: a housing that accommodates a conductor and a magnetic sensor in a positioned state, and has a first opening portion that allows the magnetic sensor to be inserted into the accommodation space; an insulating cover that covers the first opening portion and has a second opening portion for connecting the conductor to the outside of the housing; and a cover magnetic shielding portion that is positioned on the cover; the housing has a positioning portion that has an outer edge portion that is engaged with the second opening portion of the cover and is positioned; the positioning portion has an opening portion that accommodates and fixes a conductive cylindrical nut that is engaged with one end of the conductor; the nut constitutes a part of a terminal electrode for electrically contacting the other side terminal with the conductor. The nut is integrally formed with the housing, and is arranged in an electrode accommodation portion of the positioning portion of the housing to be in a state of being electrically engaged with one end of the conductor.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6402089 Summary of the invention

[0006] Technical problem to be solved by the invention

[0007] However, in the current sensor described in Patent Document 1, when the nut and the housing are integrally formed, the nut needs to be supported by a clamping pin or the like in order to ensure electrical connection with one end of the conductor. After the forming is completed, the portion that originally abutted against the clamping pin is exposed. Therefore, there is a concern that the shavings generated when the bolt for fixing the external terminal is screwed into the nut may fall to the outside of the current sensor, causing a malfunction. In addition, if the current sensor is shipped and used in such an exposed state, foreign matter that enters from the exposed portion may cause the originally insulated area to be energized, causing insulation failure.

[0008] Furthermore, in the case where the nut is not embedded in the housing, but the portion of the conductor (bus bar) connected to the external terminal is made to protrude from the housing and the protruding portion is fastened to the external terminal, when fastening the external terminal, a retaining fixture must be used to hold the conductor and the nut at the same time, which requires complicated operations.

[0009] Therefore, an object of the present invention is to provide a current sensor that can prevent the occurrence of adverse conditions caused by cutting powder caused by the screwing of a nut and a bolt, and can prevent foreign matter from entering the installation portion of the nut to suppress the occurrence of poor insulation. In addition, a further object of the present invention is to provide a current sensor that can be easily fastened to a bus bar without having to hold the bus bar or the nut with a holding fixture when fastening an external terminal to the bus bar.

[0010] Means for solving technical problems

[0011] In order to solve the above technical problems, the current sensor of the present invention comprises: a bus bar, through which the measured current flows; a nut, which is used to fix the contact between the bus bar and the external terminal; a magnetic sensor, which can detect the magnetic field generated by the current flowing through the bus bar; a shell component, which has a storage portion that can accommodate the magnetic sensor and seals the bus bar and the nut; and a cover component, which is configured in a manner to cover the storage portion, and is characterized in that the shell component has an open portion through which a portion of the nut is exposed, and the open portion is covered by an insulating protective component.

[0012] Thus, since the open portion is covered by the protective member, it is possible to prevent the cutting powder generated when the bolt and the nut are screwed together from falling to the outside of the current sensor. In addition, since it is possible to prevent foreign matter from intruding from the open portion into the housing member or foreign matter from adhering to the periphery of the open portion, it is possible to prevent the occurrence of poor insulation.

[0013] In the current sensor of the present invention, it is preferable that the protection member and the cover member are formed integrally.

[0014] This makes it possible to easily attach the protection member to the open portion, and since there is no need to separately manufacture only the protection member, it contributes to simplification of the manufacturing process.

[0015] In the current sensor of the present invention, it is preferred that when the surface of the housing member having the opening portion is set as the first opposing surface and the surface of the protective member opposite to the first opposing surface is set as the second opposing surface, one of the first opposing surface and the second opposing surface has a convex portion formed in the area surrounding the outer side of the opening portion when viewed from the opposing direction of the first opposing surface and the second opposing surface, and the other has a concave portion that can be engaged with the convex portion. Thus, even if a gap is formed at the position where the convex portion and the concave portion are engaged, since the gap forms a labyrinth structure, it is possible to prevent foreign matter (including liquid) from intruding and flowing out. In addition, when the protective member is assembled relative to the housing member, alignment becomes easy, which can improve manufacturing efficiency.

[0016] In the current sensor of the present invention, it is preferable that the convex portion and the concave portion are formed on planes respectively included in the first opposing surface and the second opposing surface.

[0017] As a result, the labyrinth structure formed by the convex portions and the concave portions becomes more complex, and the intrusion and outflow of foreign matter can be prevented more reliably.

[0018] In the current sensor of the present invention, preferably, the first opposing surface has a convex portion, and the second opposing surface has a concave portion.

[0019] Thus, since the housing member has a convex portion in the area surrounding the outside of the opening portion, foreign matter can be prevented from intruding from the opening portion before the protective member is assembled. Furthermore, since the wall thickness around the opening portion can be ensured, the fixing strength of the nut can be ensured.

[0020] In the current sensor of the present invention, preferably, the open portion has a recessed portion recessed toward the inside of the case member, the nut is arranged in the recessed portion, and the open portion is covered by the protective member by sealing the recessed portion with a sealing material as the protective member.

[0021] Thereby, the opening portion can be reliably covered with the sealing material, and further, since the shape of the cover member can be simplified, the manufacturing process of the cover member can be simplified.

[0022] In the current sensor of the present invention, preferably, the magnetic sensor is provided on a substrate arranged in the case member; and the substrate and the cover member are fixed to the case member by a common screw.

[0023] This allows the position of the magnetic sensor relative to the bus bar and the position of the protection member relative to the opening to be determined simultaneously with good accuracy. Therefore, it is possible to reduce measurement errors caused by variations in the arrangement positions of the components.

[0024] Effects of the Invention

[0025] According to the present invention, it is possible to prevent shavings generated when a bolt for fixing an external terminal is screwed together with a nut from falling outside the current sensor, and to prevent foreign matter from entering the nut installation portion, thereby suppressing the occurrence of insulation failure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 (a) Figure 1 (b) is a perspective view showing the structure of the current sensor according to the first embodiment of the present invention.

[0027] Figure 2 (a) is a top view of a current sensor according to a first embodiment of the present invention. Figure 2 (b) is Figure 2 (a) is a bottom view of the current sensor shown.

[0028] Figure 3It is an exploded perspective view of the current sensor according to the first embodiment of the present invention.

[0029] Figure 4 yes Figure 2 (a) is a cross-sectional view of the line S1-S1'.

[0030] Figure 5 yes Figure 4 A partial enlarged view of the vicinity of the opening portion.

[0031] Figure 6 yes Figure 4 A partial enlarged view of the vicinity of the opening portion is a view showing a state in which the cover member is separated from the shell member.

[0032] Figure 7 In the variant example, it corresponds to Figure 5 and Figure 6 A cross-sectional view of a housing component at the position of.

[0033] Figure 8 (a) Figure 8 (b) is a perspective view showing the structure of a current sensor according to a second embodiment of the present invention.

[0034] Fig. 9 It is a bottom view of a current sensor according to a second embodiment of the present invention.

[0035] Fig.10 It is a top view of a current sensor according to a second embodiment of the present invention.

[0036] Fig.11 (a) is a plan view of a cover member of a current sensor according to a second embodiment of the present invention. Fig.11 (b) is a side view of the cover member of the current sensor according to the second embodiment of the present invention.

[0037] Fig.12 It is an explanatory diagram of a current sensor according to a second embodiment of the present invention.

[0038] Fig.13 It is along Fig. 9 Cross-sectional view of line A-A. DETAILED DESCRIPTION

[0039] Hereinafter, the current sensor 10 according to the first embodiment of the present invention will be described in detail with reference to the accompanying drawings. In each figure, the X-Y-Z coordinate is represented as a reference coordinate. In the following description, the Z1-Z2 direction is referred to as the up-down direction, the X1-X2 direction is referred to as the front-back direction (width direction), and the Y1-Y2 direction is referred to as the left-right direction (longer direction). The X1-X2 direction and the Y1-Y2 direction are perpendicular to each other, including their X-Y planes that are perpendicular to the Z1-Z2 direction. In addition, there is a situation where the state of observing the lower side (Z2 side) from the upper side (Z1 side) is called a top view.

[0040] Figure 1 (a) Figure 1 (b) is a perspective view showing the structure of the current sensor 10 according to the first embodiment. Figure 1 (a) is a view from the front and upper side. Figure 1 (b) is a view viewed from below. Figure 2 (a) is a top view of the current sensor 10, Figure 2 (b) is a bottom view of the current sensor 10, Figure 3 is an exploded perspective view of the current sensor 10. Figure 3 In the figure, the screws 64 and shielding members for fixing the cover member 60 are omitted. Figure 4 yes Figure 2 (a) is a cross-sectional view of the line S1-S1', Figure 5 Yes means Figure 4 A partial enlarged view of the second opening portion 52 and its vicinity, Figure 6 is with Figure 5 The corresponding drawings show a state in which the cover member 60 is separated from the case member 50 .

[0041] like Figure 3 As shown in FIG. 1 , the current sensor 10 includes three bus bars 21, 22, and 23, three nuts 31, 32, and 33 corresponding to the bus bars, respectively, a case member 50, a cover member 60, and a substrate 70. Figure 4 As shown, a magnetic sensor 40 and three pairs of shielding members 55 and 65 are provided, and an opening portion 52 is provided on a housing member 50. In the present embodiment, three bus bars 21, 22, and 23 are provided, and three nuts and three pairs of shielding members are provided in a manner corresponding to them, but the number of bus bars can be set to any number according to the specifications of the current sensor, etc.

[0042] like Figure 4As shown, the second bus bar 22 is a metal plate-shaped member, which is bent at a substantially right angle to form an extension portion 22a and a fixing portion 22b. The extension portion 22a extends downward from the shell member 50, and the fixing portion 22b is sealed in the shell member 50 in a manner extending along the front-to-back direction (X1-X2 direction). The fixing portion 22b is provided with an insertion hole portion 22h that passes through in the thickness direction (up-down direction, Z1-Z2 direction). The insertion hole portion 22h is as shown in FIG. Figure 1 (b) Figure 2 (b) and Figure 4 As shown, the bottom surface 50u of the case member 50 is exposed to the outside from a recessed portion 50r provided in a manner recessed upward, and can be connected to an external terminal (not shown).

[0043] The first bus bar 21 and the third bus bar 23 are also made of the same metal as the second bus bar 22, and are formed by bending a plate-like member having the same thickness and width at a substantially right angle to form protruding portions 21a, 23a and fixing portions 21b, 23b, respectively. The protruding portions 21a, 23a, like the second bus bar 22, respectively protrude downward from the shell member 50, and the fixing portions 21b, 23b are respectively sealed in the shell member 50 in a manner extending in the front-to-back direction. The fixing portions 21b, 23b respectively extend in directions away from each other along the left-right direction inside the front wall portion 50w of the shell member 50. The fixing portions 21b, 23b are respectively provided with insertion holes 21h, 23h that penetrate in the thickness direction (up-down direction). The insertion holes 21h, 23h are as shown in FIG. Figure 1 (b) Figure 2 (b) and Figure 4 As shown, it is exposed to the outside from the bottom surface 50u of the case member 50.

[0044] The three bus bars 21, 22, 23 extend parallel to each other in the left-right direction, the extension portions 21a, 22a, 23a have the same width, thickness, and length, and the fixing portions 21b, 22b, 23b have the same width and thickness. The insertion holes 21h, 22h, 23h have the same shape and are provided at the same position in the front-back direction.

[0045] The housing member 50 is formed of an insulating material such as Figure 2 (a) Figure 2 As shown in (b), it has a roughly rectangular shape extending in the left-right direction when viewed from above. Figure 3As shown, a step portion 50d recessed downward is provided on the rear side of the upper portion of the housing member 50, and a storage portion 50b is provided at the bottom of the step portion 50d. The step portion 50d is a space recessed downward from the upper surface 50a of the front wall portion 50w. The storage portion 50b is recessed downward from the bottom of the step portion 50d and can accommodate the magnetic sensor 40 and the like provided on the lower surface of the substrate 70 (see Figure 4 ).

[0046] like Figure 3 As shown, the upper surface 50 a extends in the left-right direction (Y1 - Y2 direction) as a plane along the XY plane in the front wall portion 50 w of the case member 50 .

[0047] like Figure 3 As shown, on the upper surface 50a (first opposing surface) of the shell member 50, three openings 51, 52, 53 are provided at equal intervals in the left-right direction. These openings 51, 52, 53 are recessed in a circular shape when viewed from above. In addition, inside thereof, a portion of the nuts 31, 32, 33 insert-molded on the shell member 50 is exposed, respectively. In addition, the openings 51, 52, 53 are spaces formed after mold separation at a location where there were originally components (clamping pins, etc.) for holding the nuts 31, 32, 33 in the mold when the shell member 50 and the nuts 31, 32, 33 are molded together. The openings 51, 52, 53 are provided at positions corresponding to the insertion holes 21h, 22h, 23h of the bus bars 21, 22, 23, respectively.

[0048] The case member 50 is formed by insert molding so that the three bus bars 21 , 22 , 23 and the three nuts 31 , 32 , 33 are arranged at predetermined positions inside and fixed.

[0049] like Figure 5 and Figure 6 As shown, in the front wall portion 50w of the case member 50 after insert molding, the central axis extending in the vertical direction of the thread groove portion 32a provided in the interior of the second nut 32 and the insertion hole portion 22h of the second bus bar 22 are consistent with each other. Therefore, if a fixing bolt (not shown) is screwed into the insertion hole portion 22h from the recess 50r side of the case member 50 in a state where the external terminal (not shown) is in contact with the bottom surface of the second bus bar 22, the bolt is screwed into the thread groove portion 32a of the second nut 32. Therefore, by tightening the bolt with the second nut 32 via the second bus bar 22, the external terminal is fixed to the bus bar 22 in contact with the second bus bar 22, and is electrically connected to the second bus bar 22.

[0050] In addition, a structure in which the second nut 32 is not formed by inserting the second nut 32 on the housing member 50, but the portion of the bus bar 22 provided with the insertion hole 22h protrudes from the front wall portion 50w of the housing member 50, and the protruding portion is fastened to the external terminal (not shown) on the bottom surface can also be considered. However, in this structure, when fastening the external terminal, the bus bar 22 and the second nut 32 must be fixed and held at the same time. In contrast, in the case of a structure such as the current sensor 10 of the present embodiment, the bus bar 22 and the second nut 32 are also held by holding the housing member 50, so it is no longer necessary to fix and hold them separately, and the housing member 50 can play the role of a clamp for receiving the external terminal (not shown).

[0051] exist Figures 4 to 6 In the description, the connection with the external terminal is described by taking the second bus bar 22 as an example, but the electrical connection (contact and fixation) with respect to the external terminal of each of the first bus bar 21 and the third bus bar 23 can be performed in the same manner.

[0052] like Figure 3 As shown, at the bottom of the step portion 50d of the housing member 50, a substrate 70 that is roughly rectangular in top view is arranged in a manner that covers the storage portion 50b. A magnetic sensor 40 is fixed on the lower surface of the substrate 70, and the magnetic sensor 40 is inserted into the storage portion 50b. The magnetic sensor 40 is configured to be located above the fixed portion 22b of the second bus bar 22. Thus, the magnetic sensor 40 can detect the magnetic field generated by the measured current flowing through the second bus bar 22. The magnetic sensor 40 is composed of a magnetoresistive element such as a GMR element (giant magnetoresistive element).

[0053] like Figure 4 As shown, in the normal direction (Z1-Z2 direction) of the X-Y plane, a pair of first shielding member 55 and second shielding member 65 are arranged so as to sandwich the magnetic sensor 40 from above and below. The first shielding member 55 is sealed inside the housing member 50 when the housing member 50 is formed, and the second shielding member 65 is sealed inside the cover member 60 when the cover member 60 is formed. Thus, it is possible to prevent the external magnetic field from reaching the magnetic sensor 40, and the magnetic field generated by the current flowing through the second bus bar 22 can be detected with good accuracy in the magnetic sensor 40.

[0054] The magnetic sensor 40 is also provided with two magnetic sensors respectively above the first bus bar 21 and the third bus bar 23 on the lower surface of the substrate 70, and each magnetic sensor detects the magnetic field generated by the current flowing through the opposing bus bars. In a manner that sandwiches the two magnetic sensors, two pairs of shielding members are respectively sealed in the housing member 50 and the cover member 60, similarly to the first shielding member 55 and the second shielding member 65.

[0055] like Figure 1 or Figure 3 As shown, the cover component 60 is roughly rectangular in a plan view, and is fixed to the shell component 50 by nailing 7 screws 64 in a manner that covers the step portion 50d of the shell component 50 together with the substrate 70 arranged inside it. In addition, the screw hole of the cover component 60 and the screw hole of the substrate 70 are set to be coaxial in the up and down direction (Z1-Z2 direction), and are threadedly fastened relative to the shell component 50 with a common screw 64. By fixing in this way, the first shielding component 55, the second shielding component 65, each bus bar and the magnetic sensor 40 are positioned at a specified position. Therefore, the measurement error caused by the deviation of the configuration position of each component can be reduced. The cover component 60 is made of an insulating material, for example, manufactured by resin molding. In the manufacture of the cover component 60, insert molding is performed to seal the above-mentioned second shielding component 65.

[0056] On the upper surface of the front end of the cover member 60, three protective covers 61, 62, 63 are provided as protective members at positions corresponding to the three openings 51, 52, 53 of the housing member 50. These protective covers 61, 62, 63 are made of the same insulating material as the cover member 60, and are respectively provided in a manner extending forward from the front end of the cover member 60, forming a plate-like shape in a top view that covers the openings 51, 52, 53 from above. If the protective covers 61, 62, 63 are integrally formed with the cover member 60, it is possible to easily and correctly perform alignment with respect to the openings 51, 52, 53, so it is preferred. In addition, if the protective covers 61, 62, 63 are made of an elastic material, they are in elastic contact with respect to the openings 51, 52, 53, so the close contact is improved, and the intrusion of foreign matter into the openings 51, 52, 53 can be effectively prevented.

[0057] like Figure 5 and Figure 6 As shown, in the case member 50, when the upper surface 50a having the openings 51, 52, 53 is set as the first opposing surface, the lower surface 60u of the cover member 60 forms a plane (second opposing surface) opposing the upper surface 50a (first opposing surface). Figure 6 As shown, on the upper surface 50a of the housing member 50, when viewed from the opposing direction (Z1-Z2 direction) in which the upper surface 50a and the lower surface 60u are opposed to each other, a convex portion 52a is provided in the region surrounding the outer side of the opening portion 52, and on the second protective cover 62, a concave portion 62a having a shape that can be engaged with the convex portion 52a when the second protective cover 62 is placed on the opening portion 52 is provided. The opening portion 52 is formed into a circular shape in plan view by the inner peripheral surface 52b of the convex portion 52a.

[0058] Here, the shape of the second opening portion 52 and the shape of the second protective cover 62 corresponding to the second opening portion 52 are the same as the first opening portion 51 and the third opening portion 53 and the first protective cover 61 and the third protective cover 63 corresponding thereto.

[0059] like Figure 3 As shown, the convex portion 52a protrudes upward from the upper surface 50a of the case member 50 and is formed in an annular shape in a plan view. The concave portion 62a of the cover member 60 is formed in a shape corresponding to the convex portion 52a, that is, in an annular shape when viewed from the bottom.

[0060] In the cover member 60, a recessed portion 62b is provided inside the recessed portion 62a so as to have a central axis common to the central axis of the annular recessed portion 62a. The recessed portion 62b is arranged above the second nut 32 so that the thread groove portion 32a of the second nut 32 coincides with the central axis when the cover member 60 is arranged on the housing member 50.

[0061] Alternatively, a concave portion may be provided on the case member 50 side, and a convex portion may be provided on the cover member 60 side so as to be engageable with the concave portion.

[0062] like Figure 5 and Figure 6 As shown, the inner peripheral surface 52b forming the opening portion 52 is provided continuously with the receiving space 52c receiving the second nut 32 in the front wall portion 50w of the housing member 50. The inner peripheral surface of the receiving space 52c has a shape along the outer peripheral surface of the second nut 32. Figure 6 As shown, a groove portion 32b that is recessed inward is provided at a substantially central position in the up-down direction on the outer peripheral surface of the second nut 32. A protrusion 52d having a shape corresponding to the groove portion 32b is provided on the inner peripheral surface of the receiving space 52c. Thus, since the groove portion 32b and the protrusion 52d are meshed with each other, the fixing strength of the second nut 32 relative to the housing member 50 can be improved, so when the external terminal is screwed with the second bus bar 22 or when a force from the outside acts after the external terminal is fixed, the second nut 32 can be prevented from being disengaged or damaged.

[0063] The current sensor 10 is manufactured by an insert molding process of the housing member 50, an integral molding process of the cover member 60, a mounting process of the substrate 70, and an assembly process of sequentially mounting the substrate 70 and the cover member 60 on the molded housing member 50. The external terminals are fastened to the bus bars 21, 22, 23, and the magnetic sensors corresponding to (opposing) the bus bars detect the magnetic field generated by the current to be measured flowing through the bus bars 21, 22, 23, and based on the detection result, the current value of the current to be measured is detected.

[0064] In the insert molding process of the case member 50, molding is performed so that the three bus bars 21, 22, 23 and the three nuts 31, 32, 33 are respectively arranged at predetermined positions of the case member 50, thereby sealing the bus bars 21, 22, 23 and the nuts 31, 32, 33 in the case member 50. In this process, in order to position the nuts 31, 32, 33, positioning members such as pins are arranged in the mold for molding the case member 50, and the positioning members are removed after the insert molding.

[0065] As a result of the insert molding process, the extension portions 21a, 22a, 23a of the three bus bars 21, 22, 23 extend downward from the bottom surface 50u of the case member 50, respectively, and the insertion holes 21h, 22h, 23h are exposed in the bottom surface 50u of the case member 50 so as to enable connection of external terminals. In addition, the three nuts 31, 32, 33 are partially exposed, that is, the upper portions, from the opening portions 51, 52, 53 by removing the above-mentioned positioning members.

[0066] In the integral molding step of the cover member 60 , the cover member 60 and the three protection covers 61 , 62 , and 63 are integrally molded.

[0067] Since the openings 51, 52, 53 are reliably covered by the protective covers 61, 62, 63 as the protective members, it is possible to prevent the chips generated when the bolts for fixing the external terminals and the nuts 31, 32, 33 are screwed together and fall to the outside to cause a malfunction. Furthermore, it is possible to prevent foreign matter from entering or mixing into the inside of the openings 51, 52, 53 or the inside of the housing space 52c that houses the nuts 31, 32, 33 in the housing member 50, and the occurrence of insulation failure can be suppressed.

[0068] Since the protection covers 61 , 62 , 63 are integrally formed on the cover member 60 , the protection covers 61 , 62 , 63 can be reliably and accurately arranged on the openings 51 , 52 , 53 .

[0069] By providing the convex portion 52a on the housing member 50 and providing the concave portion 62a at a position corresponding to the convex portion 52a in the cover member 60, even if a gap is formed at the position where the convex portion 52a and the concave portion 62a are engaged, the gap forms a labyrinth structure, so the effect of preventing foreign matter from entering and flowing out is high. In addition, the cover member 60 is easily aligned when assembled with respect to the housing member 50.

[0070] Modifications of the first embodiment will be described below.

[0071] Figure 7 In the variant example Figure 5 and Figure 6A cross-sectional view of the housing member 50 at a corresponding position.

[0072] like Figure 7 As shown, the space (recess) surrounded by the inner peripheral surface 52b of the second opening portion 52 is sealed with an insulating sealing material 160, such as a resin material, as a protective member. Thus, it is possible to prevent foreign matter from intruding into the interior of the second opening portion 52. The sealing by the insulating sealing material 160 is performed after the insert molding process of the above-mentioned housing member 50, after the removal of the positioning member for positioning the nuts 31, 32, 33, and before the assembly process of the substrate 70 and the cover member 60 relative to the housing member 50.

[0073] The structure and sealing process of sealing the recessed portion with the insulating sealing material 160 are the same for the first opening portion 51 and the third opening portion 53 other than the second opening portion 52. In addition, the structure of the modified example can also be applied to a cover member without forming the protective cover 61, 62, 63, but if the cover member 60 having the protective cover 61, 62, 63 is used as in the above-mentioned embodiment, the effect of preventing the intrusion of foreign matter can be further improved.

[0074] Next, the structure of a current sensor according to a second embodiment of the present invention will be described. Figure 8 (a) Figure 8 (b) is a perspective view showing the structure of a current sensor according to a second embodiment of the present invention. Figure 8 (a) is the view from below. Figure 8 (b) is a view viewed from above. Fig. 9 It is a bottom view of a current sensor according to a second embodiment of the present invention. Fig.10 It is a top view of a current sensor according to a second embodiment of the present invention. Fig.11 (a) is a bottom view of a cover member of a current sensor according to a second embodiment of the present invention. Fig.11 (b) is Fig.11 (a) is a side view of the cover part shown. Fig.12 It is an explanatory diagram of a case member of a current sensor according to a second embodiment of the present invention.

[0075] like Figure 8As shown in FIG. 1 , the current sensor 200 according to the second embodiment of the present invention has a structure in which a bus bar 220 is incorporated in a housing member 250, similarly to the current sensor 100 according to the first embodiment of the present invention. The bus bar 220 is formed by a plate formed of a conductive material extending in the X1-X2 direction, and has exposed portions at both ends in the X1-X2 direction, and has insertion holes 221h and 222h in each exposed portion. In the current sensor 200, a plurality of connector pins 280 that receive power from the outside and output signals to the outside protrude toward the Z2 side in the Z1-Z2 direction.

[0076] like Figure 8 (b) and Fig.10 As shown in FIG. 1 , a cover member 260 is provided on the surface of the current sensor 200 on the Z1 side in the Z1-Z2 direction. Figure 3 As shown, the protective covers 61, 62, 63 positioned so as to cover the openings 51, 52, 53 where the nuts 31, 32, 33 are arranged protrude further toward the direction in which the openings 51, 52, 53 are opened (Z1 side in the Z1-Z2 direction) than other parts of the cover member 60. Fig.11 As shown in (b), the cover member 260 of the second embodiment is in the direction (Z1 side in the Z1-Z2 direction, see Fig.12 ) has no protrusion. Fig.12 2 shows a view in which the cover member 260 is removed so that the internal structure of the housing member 250 can be easily understood.

[0077] like Fig.12 As shown, the current sensor 200 of the second embodiment is similar to the current sensor 100 of the first embodiment, and the housing member 250 has a step portion 250d for accommodating the substrate 270, but is different from the first embodiment in that the step portion 250d is formed to extend to the periphery of the opening portion 251. Thus, since the step portion 250d is provided to extend to the periphery of the opening portion 251, the cover member 260 does not have a protruding portion on the Z1 side in the Z1-Z2 direction, unlike the protective covers 61, 62, and 63 of the cover member 60 in the current sensor 100 of the first embodiment. The current sensor 200 of the second embodiment is also different from the first embodiment in this respect. Thus, when the cover member 260 is mounted on the housing member 250, the entire cover member 260 is arranged in the step portion 250d, and the current sensor 200 no longer has a protruding portion on the Z1 side in the Z1-Z2 direction. Therefore, the degree of freedom of arrangement of the current sensor 200 in the device in which the current sensor 200 is incorporated can be improved.

[0078] Fig.13 It is along Fig. 9A-A line cross-sectional view. Fig.13 As shown, a nut 230 is embedded on the Z1 side of the Z1-Z2 direction of the portion of the housing member 250 where the insertion hole portion 221h of the bus bar 220 is located. The nut 230 is formed integrally with the housing member 250 by insert molding when the resin housing member 250 is molded. On the Z1 side of the Z1-Z2 direction of the portion of the housing member 250 where the nut 230 is embedded, a housing flat bottom countersunk portion 250r is provided on the bottom surface of which the nut 230 is located. An annular convex portion 250a is provided on the housing flat bottom countersunk portion 250r so as to surround the nut 230 when viewed from the Z1 side of the Z1-Z2 direction. The end of the convex portion 250a on the Z1 side of the Z1-Z2 direction is located closer to the Z2 side of the Z1-Z2 direction than the end surface of the other portion of the housing member 250 on the Z1 side of the Z1-Z2 direction. That is, the entire annular convex portion 250a is located inside the housing flat bottom counterbore portion 250r.

[0079] like Fig.11 (a) and Fig.13 As shown, when the cover member 260 is assembled as the current sensor 200, the cover member 260 has a cover flat bottom countersunk portion 260r that is recessed toward the Z1 side in the Z1-Z2 direction at a portion that is opposite to the shell flat bottom countersunk portion 250r of the shell member 250. On the bottom surface of the cover flat bottom countersunk portion 260r, an annular cover convex portion 260p similar to the shell flat bottom countersunk portion 250r is provided. When assembled as the current sensor 200, the convex portion 250a of the cover member 260 enters the inside of the annular concave portion 260a of the cover flat bottom countersunk portion 260r located on the outer peripheral side of the cover convex portion 260p, forming a labyrinth structure.

[0080] In this way, by providing flat-bottomed countersunk portions having annular convex portions on the bottom surfaces of the shell component 250 and the cover component 260, respectively, and arranging these flat-bottomed countersunk portions so that the convex portions are engaged with each other, the current sensor 200 has a flat structure without a protrusion on the Z1 side in the Z1-Z2 direction, and at the same time, the surface distance of the labyrinth structure is lengthened compared to the case of the current sensor 100 using the protective covers 61, 62, and 63.

[0081] The present invention has been described with reference to the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, and can be improved or modified for the purpose of improvement or within the scope of the concept of the present invention.

[0082] Industrial Applicability

[0083] As described above, the current sensor of the present invention is useful in preventing chips generated when the bolt used to fix the external terminal is screwed into the nut and falling to the outside of the current sensor, and further preventing foreign matter from invading the setting part of the nut used to connect and fix the bus bar and the external terminal.

[0084] Description of Reference Numerals

[0085] 10, 200 current sensor

[0086] 21, 22, 23, 220 Busbars

[0087] 21a, 22a, 23a Extension

[0088] 21b, 22b, 23b Fixed part

[0089] 21h, 22h, 23h, 221h, 222h Insertion hole

[0090] 31, 32, 33, 230 Nuts

[0091] 32a Thread groove

[0092] 32b Groove

[0093] 40 Magnetic Sensor

[0094] 50, 250 housing parts

[0095] 50a Upper surface of housing member

[0096] 50b Storage area

[0097] 50d, 250d step difference

[0098] 50r recess

[0099] 50u Bottom of the housing part

[0100] 50w front wall

[0101] 51, 52, 53, 251 Open Department

[0102] 52a, 250a convex portion

[0103] 52b Inner peripheral surface of convex portion

[0104] 52c Containment Chamber

[0105] 52d protrusion

[0106] 55, 65 Shielding components

[0107] 60, 260 cover parts

[0108] 60u Lower surface of the cover part

[0109] 61, 62, 63 Protective cover (protective component)

[0110] 64 Screws

[0111] 62a, 262 concave portion

[0112] 62b recess

[0113] 70, 270 substrate

[0114] 160 Sealing material (protective component)

[0115] 250r Shell flat bottom countersink

[0116] 260a recess

[0117] 260p hood convex part

[0118] 260r cover flat bottom countersink

[0119] 280 connector pins

Claims

1. A current sensor comprising: A bus bar having a fixing portion for fixing an external terminal and through which a current to be measured flows; A nut capable of being screwed into a fixing bolt for contact fixing between the bus bar and the external terminal, wherein the fixing bolt is inserted into an insertion hole provided in the fixing portion; a magnetic sensor capable of detecting a magnetic field generated by current flowing through the bus bar; a housing member having a housing portion capable of housing the magnetic sensor and sealing the bus bar and the nut therein; and The cover member is arranged so as to cover the storage portion. It is characterized in that The housing member has an open portion through which a portion of the nut including an opening is exposed, and the opening is an opening on the side of the nut opposite to the fixing portion of the bus bar. Even before the fixing bolt is screwed into the nut, the entire opening portion is covered by the insulating protective member. When the surface of the housing member provided with the opening portion is set as the first facing surface, and the surface of the protection member facing the first facing surface is set as the second facing surface, On one of the first opposing surface and the second opposing surface, there is a convex portion formed in an area surrounding the outer side of the opening portion when viewed from the opposing direction of the first opposing surface and the second opposing surface, and on the other side there is a concave portion that can engage with the convex portion.

2. The current sensor according to claim 1, wherein: The protection member is formed integrally with the cover member.

3. The current sensor according to claim 1 or 2, wherein: The convex portion and the concave portion are formed on planes respectively provided on the first opposing surface and the second opposing surface.

4. The current sensor according to claim 1 or 2, wherein: The first opposing surface has the convex portion, and the second opposing surface has the concave portion.

5. The current sensor according to claim 3, wherein: The first opposing surface has the convex portion, and the second opposing surface has the concave portion.

6. The current sensor according to claim 1, wherein: The open portion has a recessed portion recessed toward the inside of the housing member, the nut is arranged in the recessed portion, and the open portion is covered by the protective member by sealing the recessed portion with a sealing material serving as the protective member.

7. The current sensor according to claim 2, wherein: The magnetic sensor is provided on a substrate disposed in the housing member. The substrate and the cover member are fixed to the case member by common screws.

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