Current sensor

Abstract

To provide a current sensor of a novel configuration which can be efficiently assembled and enables a shield case to be securely fixed.SOLUTION: A current sensor 10 comprises: a shield case 40 for accommodating a coil member 12; a disc spring 40; and a housing 18 for accommodating the shield case 40 and the disc spring 40. The housing 18 is formed by combining a first housing 60 having a first engagement part 67 and a second housing 70 having a second engagement part 77 top and bottom. The disc spring 40 presses the shield case 40 downward. The shield case 40 is pressed toward the second housing 70. The disc spring 40 presses the first housing 60 upward. The first engagement part 67 and the second engagement part 77 are pressed upward and downward respectively by the application of pressure of the disc spring 40, whereby the combination of the first housing 60 and the second housing 70 is maintained.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a current sensor including a coil member, a shield case that houses the coil member, and a housing that houses the shield case. [Background technology]

[0002] Patent Document 1 discloses a current sensor including a coil member, two shield plates sandwiching the coil member from above and below, and an annular case (housing) that houses the coil member and the shield plates. The coil member includes an annular core housed in a core case, and a coil wound around the core case. One of the shield plates (a lower shield plate) is fixed below the lower surface of the housing. The other of the shield plates (an upper shield plate) is fixed near the upper end of the housing. As a result, the coil member is sandwiched between the upper shield plate and the lower surface of the housing in the vertical direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6520335 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the structure of Patent Document 1, each shield plate needs to be attached to the housing using an engagement claw. With this fixing method, if the dimensions of the components differ from the design values ​​due to manufacturing tolerances, the shield plate may not be fixed securely. In addition, the assembly process of the current sensor becomes complicated. If the current sensor is provided with a shield case that houses the coil member instead of two shield plates, the above problem becomes even more pronounced.

[0005] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a current sensor having a new structure that enables efficient assembly of the current sensor and secure fixing of the shield case. [Means for solving the problem]

[0006] The present invention provides a first current sensor, A current sensor including a coil member, a shield case, a housing, and a disc spring, The coil member includes a core and a coil. the core has a toroidal shape, The coil has a winding portion, The winding portion is wound around the core, The core and the winding portion are housed in the shield case, The housing includes a first housing and a second housing, the first housing and the second housing are combined with each other in a vertical direction to form the housing, The first housing has a first engagement portion, The second housing has a second engagement portion, the first engagement portion and the second engagement portion are engaged with each other, the shield case and the disc spring are accommodated in the housing, the disc spring applies pressure to the shield case in a predetermined direction along the up-down direction, whereby the shield case is pressed against the second housing in the predetermined direction, the disc spring presses the first housing in a direction opposite to the predetermined direction, whereby the first housing is pressed away from the second housing; The first engagement portion and the second engagement portion are pressed against each other in the up-down direction by the pressure of the shield case and the first housing by the disc spring, thereby maintaining the combination of the first housing and the second housing. A current sensor is provided.

[0007] The present invention provides a second current sensor comprising a first current sensor, The shield case includes an upper shield case and a lower shield case, the upper shield case is an upper member of the shield case, the lower shield case is a lower member of the shield case, the second housing is located below the lower shield case, the lower shield case is fixed to the second housing, the first housing is located above the upper shield case, The disc spring is located between the first housing and the upper shield case in the vertical direction. A current sensor is provided.

[0008] The present invention provides a third current sensor, which is the first current sensor, The current sensor includes a bus bar. the bus bar has an inner held portion, an outer held portion, and a connecting portion, The inner held portion and the outer held portion each extend along the up-down direction, The connecting portion connects an upper end of the inner held portion and an upper end of the outer held portion to each other in a direction perpendicular to the up-down direction, The housing has an inner retaining hole and an outer retaining hole formed therein, The inner retained portion is received and retained in the inner retaining hole, The outer held portion is received and held in the outer holding hole, The housing has a protrusion, The protrusion protrudes upward from an upper surface of the housing, The connecting portion is located on the protrusion and is spaced upward from the upper surface of the housing. A current sensor is provided.

[0009] The present invention provides a fourth current sensor, which is the first current sensor, The shield case includes an upper shield case and a lower shield case, the upper shield case is an upper member of the shield case, the lower shield case is a lower member of the shield case, The disc spring has an inner spring portion and an outer spring portion, the inner spring portion is located on an inner periphery of the disc spring in a horizontal plane perpendicular to the up-down direction and presses the shield case in the predetermined direction, the outer spring portion is located on an outer periphery of the disc spring in the horizontal plane and presses the first housing in the opposite direction, The upper shield case and the lower shield case abut against each other on the inner periphery in the horizontal plane, and face each other at a distance above and below on the outer periphery in the horizontal plane. A current sensor is provided.

[0010] The present invention provides a fifth current sensor, which is the fourth current sensor, the first engagement portion is located on an outer periphery of the first housing in the horizontal plane, The second engagement portion is located on the outer periphery of the second housing in the horizontal plane. A current sensor is provided.

[0011] The present invention provides a sixth current sensor, which is the fifth current sensor, The first housing has a first outer periphery, the first outer periphery is located on an outer periphery of the first housing in the horizontal plane, the first engagement portion is a recess formed in the first outer circumferential portion and is open in the horizontal plane; The second housing has a second outer periphery. the second outer periphery is located on an outer periphery of the second housing in the horizontal plane, the second engagement portion is a protrusion provided on the second outer circumferential portion and protrudes outwardly from the horizontal plane, At least one of the protrusion and the recess is movable by utilizing the elasticity of the housing, The protrusion is received in the recess, The lower inner wall surface of the recess and the lower surface of the protrusion are pressed against each other in the up-down direction. A current sensor is provided.

[0012] The present invention provides a seventh current sensor, which is a first current sensor, The disc spring has two or more slits formed therein, Each of the slits extends from a center of the disc spring in a horizontal plane perpendicular to the up-down direction toward an outside of the horizontal plane. A current sensor is provided.

[0013] The present invention provides an eighth current sensor, which is a first current sensor, The disc spring is made of metal or any one of the following resins: POM (polyacetal), LCP (liquid crystal polymer), and PEEK (polyether ether ketone). A current sensor is provided. Effect of the Invention

[0014] According to the present invention, by simply disposing one disc spring inside the housing, the combination of the first housing and the second housing can be maintained by the spring force of the disc spring. In addition, the spring force of this disc spring can press the shield case containing the core and coil against the housing to fix it so that it does not move. In other words, according to the present invention, it is possible to provide a current sensor having a new structure that enables efficient assembly of the current sensor and reliable fixing of the shield case. [Brief description of the drawings]

[0015] [Figure 1] 1 is a perspective view showing a current sensor according to an embodiment of the present invention, in which a part of a circuit board on which the current sensor is mounted is drawn by a dashed line. [Diagram 2] 2 is another perspective view showing the current sensor of FIG. 1. [Diagram 3] 2 is a top view showing the current sensor of FIG 1. The outline of a bus bar is drawn by a dashed line. [Figure 4] 4 is a cross-sectional view showing the current sensor taken along line IV-IV in Fig. 3. A part of the current sensor (a part surrounded by a dashed line) is drawn in an enlarged manner. [Diagram 5] 4 is a cross-sectional view showing the current sensor taken along line V-V of Fig. 3. A part of the current sensor (a part surrounded by a dashed line) is drawn in an enlarged manner. [Figure 6] 2 is a front view showing the current sensor of FIG 1, with a portion of the circuit board drawn with a dashed line. [Figure 7] FIG. 2 is a side view showing the current sensor of FIG. [Figure 8] 2 is a bottom view showing the current sensor of FIG 1, without depicting the bus bar. [Figure 9] FIG. 2 is an exploded perspective view showing the current sensor of FIG. 1. A part of the upper housing (part surrounded by dashed lines) and a part of the lower housing (part surrounded by dashed lines) are drawn on an enlarged scale. One of the bus bars is drawn on an enlarged scale. A part of the winding part of the coil and a part of the end part of the coil are drawn typically. A part of the hidden outline of the upper shield case and the outline of the core housed in the core case are drawn by dashed lines. [Figure 10] 10 is a perspective view showing a shield case of the current sensor of Fig. 9. Part of the hidden outline of the lower shield case and part of the end of the coil are drawn with dashed lines. [Figure 11] 10 is a perspective view showing a disc spring of the current sensor of FIG. 9. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] 1, a current sensor 10 according to an embodiment of the present invention is a zero-phase current transformer (ZCT) for detecting a ground fault. The current sensor 10 includes five bus bars 70 made of a conductor and two terminals 78 made of a conductor. The current sensor 10 is mounted on a circuit board 80 for use.

[0017] When the current sensor 10 is mounted on the circuit board 80, the bus bar 70 is connected to a primary circuit pattern (not shown) formed on the circuit board 80, and the terminal 78 is connected to a secondary circuit pattern (not shown) formed on the circuit board 80. At this time, a three-phase, four-wire (however, the N-phase (neutral phase) is two-wire) AC current (primary current) flows through the bus bar 70. When a ground fault occurs, the balance of the primary current flowing from the primary circuit pattern to the bus bar 70 is lost, causing a secondary current (ground fault current) to flow from the terminal 78 to the secondary circuit pattern. By measuring the ground fault current, it can be detected whether or not a ground fault has occurred.

[0018] The current sensor 10 of this embodiment functions as described above. However, the present invention is not limited to this, and can be applied to various current sensors such as a direct current transformer (DCCT). Furthermore, the bus bars 70 and the terminals 78 may be provided as necessary. When the bus bars 70 are provided, the number of the bus bars 70 may depend on the application.

[0019] Referring to FIG. 9, the current sensor 10 of the present embodiment includes, in addition to the bus bar 70 and the terminal 78, a first housing (upper housing) 50 made of an insulator, a disc spring 40 made of an insulator, an upper shield case 30U made of a metal, a coil member 12, a lower shield case 30L made of a metal, and a second housing 60 made of an insulator.

[0020] Referring to Fig. 10 together with Fig. 9, the upper shield case 30U and the lower shield case 30L are combined with each other to form the shield case 30 that houses the coil member 12. Referring to Fig. 2 together with Fig. 9, the first housing 50 and the second housing 60 are combined with each other to form the housing 18 that houses the shield case 30 and the disc spring 40. That is, referring to Fig. 9, the current sensor 10 of the present embodiment includes the coil member 12, the shield case 30, the housing 18, the disc spring 40, a bus bar 70, and a terminal 78.

[0021] The current sensor 10 of the present embodiment is an assembly of the above-mentioned components and includes only the above-mentioned components. However, the present invention is not limited to this. For example, the current sensor 10 may include other components in addition to the above-mentioned components.

[0022] The coil member 12 of this embodiment will be described below.

[0023] The coil member 12 of this embodiment includes a core 20 made of a soft magnetic material, a core case 22 made of an insulator, a core cover 24 made of an insulator, and a coil 26 made of a coated electric wire. The coil member 12 of this embodiment includes only the above-mentioned members. However, the present invention is not limited to this. For example, the coil member 12 may include other members in addition to the above-mentioned members.

[0024] The core 20 has a toroidal shape (ring shape). A ring-shaped internal space is formed in the core case 22. The core 20 is accommodated in the internal space of the core case 22. The core cover 24 is attached and fixed to the core case 22 from above in the vertical direction, and covers the internal space from above. As a result, the core 20 is fixed inside the core case 22 so as not to move, and is completely surrounded by an insulator.

[0025] The up-down direction in this embodiment is the Z direction. In this embodiment, "upward" is the +Z direction, and "downward" is the -Z direction. Terms indicating positional relationships such as up-down directions in this invention do not indicate absolute positional relationships with respect to the ground, but merely indicate relative positional relationships when considering that core 20 extends along a horizontal plane (XY plane) perpendicular to the up-down direction.

[0026] The coil 26 has a winding portion 27 and two ends 28. Although only a part of the winding portion 27 is drawn in FIG. 9, the winding portion 27 is wound around the entire circumference of the core case 22 and the core cover 24. That is, the winding portion 27 in this embodiment is indirectly wound around the core 20 via the core case 22 and the core cover 24. However, the present invention is not limited to this. For example, the core case 22 and the core cover 24 may be provided as necessary. When the core case 22 and the core cover 24 are not provided, the winding portion 27 may be directly wound around the core 20. In addition, the winding portion 27 may be densely wound around the core 20 or sparsely wound around the core 20. That is, the winding portion 27 may be wound around the core 20 as long as it is wound around the core 20.

[0027] The two end portions 28 in this embodiment are both ends of the coated electric wire. Each of the end portions 28 extends forward from the core case 22 and the core cover 24 in a front-rear direction perpendicular to the up-down direction. The front-rear direction in this embodiment is the X direction. In this embodiment, "front" is the +X direction, and "rear" is the -X direction. The end portions 28 are respectively tied to the upper portions of the two terminals 78 in the assembled current sensor 10 (see FIG. 1). When the terminals 78 are connected to a secondary circuit pattern (not shown) of the circuit board 80 (see FIG. 1), the coil 26 is electrically connected to the secondary circuit pattern.

[0028] The coil 26 of the present embodiment has the above-described structure. Each of the end portions 28 is a part of a single coated electric wire. However, the present invention is not limited to this. For example, each of the end portions 28 may be welded to the winding portion 27.

[0029] The shield case 30 of this embodiment will be described below.

[0030] 10 together with FIG. 9, the shield case 30 of this embodiment includes an upper shield case 30U, an upper protective tape 37U made of an insulator, a lower shield case 30L, and a lower protective tape 37L made of an insulator. The upper shield case 30U and the lower shield case 30L are combined with each other in the up-down direction to form the shield case 30. The upper shield case 30U is an upper member of the shield case 30. The lower shield case 30L is a lower member of the shield case 30.

[0031] The shield case 30 of the present embodiment includes only the above-mentioned members. However, the present invention is not limited to this. For example, the shield case 30 may include other members in addition to the above-mentioned members.

[0032] The upper shield case 30U and the lower shield case 30L of this embodiment have outer shapes that are mirror-symmetrical with respect to the XY plane. More specifically, the upper shield case 30U and the lower shield case 30L each have a ring shape. A ring-shaped upper space 39U is formed in the upper shield case 30U. The upper space 39U opens downward. A ring-shaped lower space 39L is formed in the lower shield case 30L. The lower space 39L opens upward.

[0033] The upper protective tape 37U and the lower protective tape 37L are each made of a soft material. The upper protective tape 37U is adhered and fixed to the upper shielding case 30U so as to cover the lower edge of the front side of the upper shielding case 30U. The lower protective tape 37L is adhered and fixed to the lower shielding case 30L so as to cover the upper edge of the front side of the lower shielding case 30L. The lower end of the upper protective tape 37U and the upper end of the lower protective tape 37L face each other in the up-down direction.

[0034] When the upper shield case 30U and the lower shield case 30L are combined with each other, a central hole 32 and a coil member accommodating portion 39 are formed. That is, the shield case 30 is formed with the central hole 32 and the coil member accommodating portion 39. The central hole 32 is located at the center of the shield case 30 in the XY plane, and has a circular shape in the XY plane. The central hole 32 penetrates the shield case 30 in the up-down direction. The coil member accommodating portion 39 is a ring-shaped space formed by an upper space 39U and a lower space 39L.

[0035] The shield case 30 has an upper surface 38U and a lower surface 38L. The upper surface 38U in this embodiment is the upper surface 38U of the upper shield case 30U, and is a flat plane parallel to the XY plane with no projections or recesses. The lower surface 38L in this embodiment is the lower surface 38L of the lower shield case 30L, and is a flat plane parallel to the XY plane with no projections or recesses.

[0036] The shield case 30 has an inner peripheral portion 34 and an outer peripheral portion 36. The inner peripheral portion 34 is an inner portion of the shield case 30 in the XY plane, and the outer peripheral portion 36 is an outer portion of the shield case 30 in the XY plane. In detail, the inner peripheral portion 34 in this embodiment is a portion of the upper surface 38U and the lower surface 38L located on the inner periphery in the XY plane. The inner peripheral portion 34 is adjacent to the central hole 32 in the XY plane and surrounds the central hole 32. The outer peripheral portion 36 in this embodiment is a portion of the upper surface 38U and the lower surface 38L located on the outer periphery in the XY plane. The outer peripheral portion 36 surrounds the inner peripheral portion 34 in the XY plane. Each of the inner peripheral portion 34 and the outer peripheral portion 36 is a flat plane parallel to the XY plane.

[0037] The coil member accommodating portion 39 of the shield case 30 accommodates the entire coil member 12 except for the end portion 28. That is, the core 20 and the winding portion 27 are accommodated in the shield case 30. The end portion 28 of the coil member 12 passes between the lower end of the upper protective tape 37U and the upper end of the lower protective tape 37L and is pulled out to the outside of the shield case 30. With this arrangement, even if the upper shield case 30U and the lower shield case 30L are pressed against each other in the vertical direction, the end portion 28 is sandwiched between the soft upper protective tape 37U and the soft lower protective tape 37L in the vertical direction, thereby preventing damage to the end portion 28.

[0038] The shield case 30 of this embodiment has the above-mentioned structure. However, as long as the shield case 30 can accommodate the core 20 and the winding portion 27, the structure of the shield case 30 is not particularly limited. For example, the lower shield case 30L may have the entire coil member accommodating portion 39 formed therein, and the upper shield case 30U may be a flat plate parallel to the XY plane. Moreover, the upper protective tape 37U and the lower protective tape 37L may be provided as necessary.

[0039] The disc spring 40 of this embodiment will be described below.

[0040] 11, the coned disc spring 40 of the present embodiment has an overall ring shape when viewed in the up-down direction. A central hole 42 is formed in the coned disc spring 40. The central hole 42 is located at the center of the coned disc spring 40 in the XY plane, and has a circular shape in the XY plane. The central hole 42 penetrates the coned disc spring 40 in the up-down direction.

[0041] The coned disc spring 40 has an inner spring portion 44 and an outer spring portion 46. The inner spring portion 44 is an inner portion of the coned disc spring 40 in the XY plane, and the outer spring portion 46 is an outer portion of the coned disc spring 40 in the XY plane. In other words, the inner spring portion 44 is a portion of the coned disc spring 40 located on the inner circumference in the XY plane. The inner spring portion 44 is adjacent to the center hole 42 in the XY plane and surrounds the center hole 42. The outer spring portion 46 is a portion of the coned disc spring 40 located on the outer circumference in the XY plane. The outer spring portion 46 surrounds the inner spring portion 44 in the XY plane.

[0042] The inner spring portion 44 protrudes downward from the outer spring portion 46. With this structure, the disc spring 40 functions as an elastic member. More specifically, when the disc spring 40 is sandwiched from above and below, the disc spring 40 is elastically deformed, and the inner spring portion 44 and the outer spring portion 46 approach each other in the vertical direction. At this time, due to the restoring force of the disc spring 40, the inner spring portion 44 generates a force directed downward, and the outer spring portion 46 generates a force directed upward.

[0043] In the present embodiment, two or more slits 47 are formed in the disc spring 40. More specifically, 24 slits 47 are formed in the disc spring 40. The slits 47 extend radially from the center of the disc spring 40 in the XY plane toward the outside of the XY plane. More specifically, the slits 47 are arranged around the center hole 42 at intervals of 15° in the XY plane. Each of the slits 47 is connected to the center hole 42 and extends from the center hole 42 to the outer spring portion 46 along the radial direction of a virtual circle centered on the center hole 42.

[0044] The disc spring 40 of this embodiment has 24 spring pieces 48 separated from one another by slits 47. The spring pieces 48 are arranged around the center hole 42 at intervals of 15° in the XY plane. Each of the spring pieces 48 is located between two slits 47 in the circumferential direction of an imaginary circle centered on the center hole 42. Each of the spring pieces 48 is connected to the outer spring portion 46 and extends to the center hole 42 along the radial direction of the imaginary circle centered on the center hole 42. The spring pieces 48 are elastically deformable independently of one another.

[0045] According to this embodiment, the outer spring portion 46 has a continuous circular ring shape, and the inner spring portion 44 is an assembly of radially inner ends of the spring pieces 48. That is, the inner spring portion 44 is an assembly of 24 free ends arranged at equal intervals around the center hole 42. With this structure, the disc spring 40 is easy to flex. However, the present invention is not limited to this. For example, the slits 47 may be formed as necessary.

[0046] The housing 18 (see FIG. 9) of this embodiment will be described below.

[0047] 9, the housing 18 of the present embodiment includes a first housing 50 and a second housing 60. Each of the first housing 50 and the second housing 60 of the present embodiment is molded from PA (polyamide) resin, and has high flexibility and high heat resistance. However, the material of each of the first housing 50 and the second housing 60 in the present invention is not particularly limited. For example, each of the first housing 50 and the second housing 60 may be molded from PPA (polyphthalamide) resin, which has even higher flexibility and high heat resistance, or may be molded from other resins.

[0048] 2 together with FIG. 9, the first housing 50 and the second housing 60 are combined with each other in the up-down direction to form the housing 18. The first housing (upper housing) 50 of the present embodiment is an upper member of the housing 18. The second housing (lower housing) 60 of the present embodiment is a lower member of the housing 18.

[0049] The housing 18 of this embodiment includes only the first housing 50 and the second housing 60 described above. However, the present invention is not limited to this. For example, the housing 18 may further include another member in addition to the first housing 50 and the second housing 60. Furthermore, as described below, the lower housing 60, which is the lower member of the housing 18, may be defined as the first housing, and the upper housing 50, which is the upper member of the housing 18, may be defined as the second housing.

[0050] 1 and 3, the housing 18 of the present embodiment has an upper surface 58 and four protrusions 582. The upper surface 58 of the present embodiment is the upper surface 58 of the first housing 50, and is a plane extending parallel to the XY plane. That is, the upper surface 58 is provided on the first housing 50. With reference to FIGS. 1 and 6, each of the protrusions 582 protrudes upward from the upper surface 58 of the housing 18. As will be described later, the protrusions 582 are portions for reducing the contact area between each of the bus bars 70 and the housing 18.

[0051] 1 and 2, a first housing 50 of the present embodiment is formed with a central hole 51. The central hole 51 is located at the center of the first housing 50 in the XY plane, and has a circular shape in the XY plane. The central hole 51 penetrates the first housing 50 in the up-down direction.

[0052] The first housing 50 of the present embodiment has an inner circumferential wall 52, an inner circumferential portion 53, and a first outer circumferential portion 54. The inner circumferential wall 52 and the inner circumferential portion 53 are inner parts of the first housing 50 in the XY plane, and the first outer circumferential portion 54 is an outer part of the first housing 50 in the XY plane. In other words, the inner circumferential wall 52 and the inner circumferential portion 53 are located on the inner periphery of the first housing 50 in the XY plane. The first outer circumferential portion 54 is located on the outer periphery of the first housing 50 in the XY plane.

[0053] Specifically, the inner circumferential portion 53 has a cylindrical shape in the XY plane and surrounds the central hole 51. The upper end of the inner circumferential portion 53 is located below the upper surface 58 of the first housing 50. That is, a space is formed directly above the inner circumferential portion 53. The lower end of the inner circumferential portion 53 is at the same position as the lower end of the first housing 50 in the up-down direction. The inner circumferential wall 52 is located outside the inner circumferential portion 53 in the XY plane. The inner circumferential wall 52 surrounds the space directly above the central hole 51 and the inner circumferential portion 53 in the XY plane.

[0054] Referring to FIG. 3, the first outer peripheral portion 54 has four overhanging portions 55 and two side wall portions 56. The side wall portions 56 are located on both sides of the first outer peripheral portion 54 in a horizontal direction perpendicular to both the up-down direction and the front-rear direction. The horizontal direction in this embodiment is the Y direction. The overhanging portions 55 are arranged around the central hole 51 at intervals of 90° in the XY plane. One of the side wall portions 56 is located between two of the overhanging portions 55 in the front-rear direction. The other of the side wall portions 56 is located between the other two of the overhanging portions 55 in the front-rear direction.

[0055] 4, an upper accommodating portion 59 is formed inside the first housing 50 of the present embodiment. The upper accommodating portion 59 is a space that opens downward. The upper accommodating portion 59 is covered from above by an upper surface 58, and is surrounded by an inner circumferential wall 52, an inner circumferential portion 53, and a first outer circumferential portion 54 in the XY plane.

[0056] 2, the housing 18 of the present embodiment has a lower surface 68. The lower surface 68 of the present embodiment is the lower surface 68 of the second housing 60, and is a plane extending parallel to the XY plane. That is, the lower surface 68 is provided on the second housing 60.

[0057] 9, a central hole 61 is formed in the second housing 60. The central hole 61 is located at the center of the second housing 60 in the XY plane, and has a circular shape in the XY plane. The central hole 61 penetrates the second housing 60 in the up-down direction.

[0058] The second housing 60 of the present embodiment has an inner circumferential wall 62 and a second outer circumferential portion 64. The inner circumferential wall 62 is an inner portion of the second housing 60 in the XY plane, and the second outer circumferential portion 64 is an outer portion of the second housing 60 in the XY plane. In other words, the inner circumferential wall 62 is located on the inner periphery of the second housing 60 in the XY plane. The second outer circumferential portion 64 is located on the outer periphery of the second housing 60 in the XY plane.

[0059] More specifically, the inner peripheral wall 62 has a cylindrical shape in the XY plane and surrounds the central hole 61. The second outer peripheral portion 64 has a front wall portion 65 and two side wall portions 66. The front wall portion 65 is located at the front end of the second outer peripheral portion 64. The two terminals 78 are held by the front wall portion 65 and extend in the up-down direction. The lower ends of the terminals 78 are located below the lower surface 68 (see FIG. 2). The side wall portions 66 are located on both sides of the second outer peripheral portion 64 in the lateral direction.

[0060] 9 together with FIG. 4, a lower accommodating portion 69 is formed inside the second housing 60. The lower accommodating portion 69 is a space that opens upward. The lower accommodating portion 69 is covered from below by a lower surface 68, and is surrounded by an inner circumferential wall 62 and a second outer circumferential portion 64 in the XY plane.

[0061] 4, when the first housing 50 and the second housing 60 having the above-mentioned structure are combined with each other, the accommodating portion 19 is formed. That is, the accommodating portion 19 is formed in the housing 18. The accommodating portion 19 is a ring-shaped space formed by an upper accommodating portion 59 of the first housing 50 and a lower accommodating portion 69 of the second housing 60. The accommodating portion 19 receives the disc spring 40 and the shielding case 30 that accommodates the core 20 and the winding portion 27. That is, the shielding case 30 and the disc spring 40 are accommodated in the housing 18. The upper end of the terminal 78 (see FIG. 2) is located inside the accommodating portion 19.

[0062] 1 and 2, two first engagement portions (recesses) 57 are formed on each side wall portion 56 of the first housing 50 of this embodiment. Referring to FIG. 9, two second engagement portions (protrusions) 67 corresponding to the two first engagement portions 57 of the side wall portion 56 are formed on each side wall portion 66 of the second housing 60 of this embodiment. That is, according to this embodiment, the first housing 50 has four first engagement portions 57, and the second housing 60 has four second engagement portions 67. The first engagement portions 57 and the second engagement portions 67 are provided to correspond to each other.

[0063] 7, when the first housing 50 and the second housing 60 are combined with each other, the first engagement portions 57 each engage with the corresponding second engagement portions 67. In other words, in the housing 18, the first engagement portions 57 and the second engagement portions 67 engage with each other. Simply applying an upward force to the first housing 50 does not cause the first housing 50 to come off from the second housing 60. Referring to FIG. 4, the housing 18 combined in this manner contains the shield case 30 and the disc spring 40 and holds them so as not to move.

[0064] The housing 18 of the present embodiment has the structure described above. However, as long as the housing 18 can accommodate the shield case 30 and the disc spring 40 and hold them so as not to move, the structure of the housing 18 is not particularly limited.

[0065] A method of assembling the current sensor 10 of this embodiment will now be described.

[0066] Referring to FIG. 9, first, the lower shield case 30L is placed in the lower accommodation portion 69 of the second housing 60 and fixed to the second housing 60 by a fixing member such as an adhesive. Next, the coil member 12 is placed in the lower space 39L of the lower shield case 30L and fixed to the lower shield case 30L by a fixing member such as an adhesive. Next, the two ends 28 of the coil 26 are respectively wound around the upper portions of the two terminals 78. Next, referring to FIG. 10 together with FIG. 9, the upper shield case 30U is placed over the coil member 12. Next, the disc spring 40 is placed on the upper surface 38U of the upper shield case 30U with the center hole 42 aligned with the center hole 32. Next, referring to FIG. 2 together with FIG. 9, the first housing 50 is attached by placing it over the second housing 60.

[0067] 5, in the attachment process of attaching the first housing 50 to the second housing 60, the inner peripheral portion 53 of the first housing 50 is received in the central hole 61 of the second housing 60, and the inner peripheral wall 62 and the second outer peripheral portion 64 of the second housing 60 are received in the upper accommodating portion 59 of the first housing 50. As a result, the housing 18 is formed with an accommodating portion 19 consisting of the upper accommodating portion 59 and the lower accommodating portion 69, and the disc spring 40 and the shield case 30 are accommodated in the accommodating portion 19. Also, in the attachment process, the first engaging portion 57 and the second engaging portion 67 engage with each other. When the first engaging portion 57 and the second engaging portion 67 engage with each other, the current sensor 10 is assembled.

[0068] In the current sensor 10 assembled as described above, the disc spring 40 is sandwiched between the first housing 50 and the upper shielding case 30U in the vertical direction and elastically deforms. The elastically deformed disc spring 40 presses the upper shielding case 30U downward, whereby the lower shielding case 30L is pressed by the upper shielding case 30U and pressed against the second housing 60. That is, the second housing 60 receives a downward force. At this time, the disc spring 40 presses the first housing 50 upward.

[0069] As can be understood from the above description, the first housing 50 and the second housing 60 are pressurized by the disc spring 40 so as to move away from each other. In particular, the first engagement portion 57 of the first housing 50 receives an upward force, and the second engagement portion 67 of the second housing 60 receives a downward force. As a result, the second engagement portion 67 is pressed against the first engagement portion 57 in the up-down direction. That is, the first engagement portion 57 and the second engagement portion 67 are pressed against each other in the up-down direction by the pressure applied by the disc spring 40 described above, and this maintains the combination of the first housing 50 and the second housing 60.

[0070] According to this embodiment, the second housing 60 is located below the lower shielding case 30L. The lower shielding case 30L is fixed to the second housing 60. The first housing 50 is located above the upper shielding case 30U. The disc spring 40 is located between the first housing 50 and the upper shielding case 30U in the up-down direction. With this arrangement, the disc spring 40 directly presses the first housing 50 (i.e., the upper housing 50) upward and indirectly presses the second housing 60 (i.e., the lower housing 60) downward. As a result, the combination of the first housing 50 and the second housing 60 is maintained.

[0071] Referring to FIG. 9, the method of assembling the current sensor 10 according to the present invention is not limited to the above-described embodiment, and can be modified in various ways. For example, the disc spring 40 may directly pressurize the lower housing 60 instead of the upper housing 50. In other words, the lower housing 60 may be the first housing that is directly pressed by the disc spring 40. In this case, the disc spring 40 may be disposed between the lower shield case 30L and the lower housing 60 (first housing) in the vertical direction. According to this arrangement, the disc spring 40 directly pressurizes the lower housing 60 (first housing) downward, and indirectly pressurizes the upper housing 50 (second housing) upward. Even with this modification, the combination of the first housing 50 and the second housing 60 can be maintained.

[0072] However, according to the above-mentioned modified example, the current sensor 10 is assembled without fixing the lower shield case 30L to the lower housing 60. According to this assembly method, in a step after arranging the coil member 12, it is necessary to maintain the position of the end 28 of the coil 26 in the vertical direction at a position where it can be entangled with the terminal 78. For this reason, it is necessary to assemble the current sensor 10 while elastically deforming the disc spring 40 using a jig (not shown). On the other hand, according to the assembly method of the present embodiment, it is not necessary to use such a jig. Therefore, unless there is a special reason, the assembly method of the present embodiment is preferable.

[0073] To summarize the above description with reference to Fig. 5, in both the assembly method of this embodiment and the assembly method of the modified example, the disc spring 40 presses the shield case 30 in a predetermined direction along the up-down direction, whereby the shield case 30 is pressed against the second housing (the lower housing 60 or the upper housing 50) in the predetermined direction. The disc spring 40 also presses the first housing (the upper housing 50 or the lower housing 60) in a direction opposite to the predetermined direction, whereby the first housing is pressed so as to move away from the second housing. The first engagement portion 57 and the second engagement portion 67 are pressed against each other in the up-down direction by the pressurization of the shield case 30 and the first housing by the disc spring 40, whereby the combination of the first housing and the second housing is maintained.

[0074] According to the assembly method of the present embodiment, the predetermined direction is a downward direction and the opposite direction is an upward direction, whereas according to the assembly method of the modified example described above, the predetermined direction is an upward direction and the opposite direction is a downward direction.

[0075] According to the conventional assembly method, the lower shielding case 30L is adhered to the second housing 60, and the upper shielding case 30U is adhered to the first housing 50. In addition, the first housing 50 is adhered to the second housing 60. A pressing tool needs to be used when the adhesive hardens. That is, fixing the members using the adhesive as described above is not only time-consuming, but also takes time for the adhesive to dry after it is applied.

[0076] On the other hand, according to the present embodiment, the first housing 50 and the second housing 60 can be assembled together with one touch by simply arranging one disc spring 40 inside the housing 18. In addition, the assembly of the first housing 50 and the second housing 60 can be maintained by the spring force of the disc spring 40. In addition, the spring force of the disc spring 40 can press the shield case 30 containing the core 20 and the coil 26 against the housing 18 to fix it so that it does not move. That is, according to the present embodiment, the curing time of the adhesive can be reduced and the number of times the pressing tool is used can be reduced. According to the present embodiment, it is possible to provide a current sensor 10 having a new structure that enables efficient assembly of the current sensor 10 and reliable fixing of the shield case 30.

[0077] 11, the disc spring 40 is easy to design the force generated by elastic deformation. In particular, the disc spring 40 having the slits 47 generates almost the same force regardless of the degree of elastic deformation. Therefore, the disc spring 40 of this embodiment is suitable for assembling the current sensor 10 (see FIG. 1). However, the present invention is not limited to this. For example, as described above, the slits 47 may be formed as necessary.

[0078] 4, the inner spring portion 44 of the disc spring 40 is located on the inner circumference of the disc spring 40 in the XY plane and presses the shield case 30 in a predetermined direction. The outer spring portion 46 of the disc spring 40 is located on the outer circumference of the disc spring 40 in the XY plane and presses the first housing 50 in the opposite direction. As described above, in this embodiment, the predetermined direction is a downward direction, and the opposite direction is an upward direction. As a result of the pressurization of the disc spring 40 described above, the upper shield case 30U and the lower shield case 30L butt against each other on the inner circumference in the XY plane and face each other at a distance from each other vertically on the outer circumference in the XY plane.

[0079] If the shield case 30 is closed without any gaps in the cross section shown in the figure, the current induced in the shield case 30 continues to flow along the cross section, which may cause problems. On the other hand, according to the present embodiment, a gap is formed between the upper shield case 30U and the lower shield case 30L, which solves the above-mentioned problem. In addition, since a gap is formed on the outer periphery of the shield case 30 in the XY plane, the end 28 (see FIG. 9) of the coil 26 can be easily entangled without being damaged. However, the present invention is not limited to this. For example, a gap may be formed on the inner periphery of the shield case 30 in the XY plane. More specifically, the disc spring 40 may be arranged upside down. In this case, a hole through which the end 28 passes may be formed on the outer periphery of the upper shield case 30U or the lower shield case 30L in the XY plane.

[0080] Referring to FIG. 9, according to this embodiment, the first engagement portion 57 is located on the outer periphery of the first housing 50 in the XY plane, and the second engagement portion 67 is located on the outer periphery of the second housing 60 in the XY plane. Referring to FIG. 5, according to this structure, the force applied by the disc spring 40 to the first housing 50 can be effectively transmitted to the first engagement portion 57. In addition, the first engagement portion 57 and the second engagement portion 67 are easy to form. However, the present invention is not limited to this. For example, the first engagement portion 57 may be located on the inner periphery of the first housing 50 in the XY plane, and the second engagement portion 67 may be located on the inner periphery of the second housing 60 in the XY plane.

[0081] According to this embodiment, the first engaging portion 57 is provided on the two side walls 56 located on both sides of the first housing 50 in the lateral direction, and the second engaging portion 67 is provided on the two side walls 66 located on both sides of the second housing 60 in the lateral direction. In addition, the two first engaging portions 57 aligned in the front-rear direction are provided on each of the side walls 56, and the two second engaging portions 67 aligned in the front-rear direction are provided on each of the side walls 66. This structure makes it possible to more reliably maintain the combination of the first housing 50 and the second housing 60. However, the present invention is not limited to this, and the arrangement of the first engaging portion 57 and the arrangement of the second engaging portion 67 can be modified as necessary. For example, the first engaging portion 57 may be further provided on the front side of the first housing 50, and the second engaging portion 67 may be further provided on the front side of the second housing 60.

[0082] According to this embodiment, each of the first engagement portions 57 is a recess 57 formed in the first outer periphery 54 of the first housing 50, and is open in the XY plane. More specifically, each of the first engagement portions 57 is open to the inside and outside of the XY plane. Meanwhile, each of the second engagement portions 67 is a protrusion 67 provided on the second outer periphery 64 of the second housing 60, and protrudes outward from the XY plane.

[0083] The protrusions 67 and the recesses 57 are each movable by utilizing the elasticity of the first housing 50 and the second housing 60 in the attachment process of attaching the first housing 50 to the second housing 60. More specifically, the protrusions 67 are pressed against the first housing 50 in the attachment process, and move while deflecting the first housing 50 and the second housing 60. In the assembled housing 18, the protrusions 67 are each received in the recesses 57. The lower inner wall surface of the recess 57 and the lower surface of the protrusions 67 are pressed against each other in the up-down direction.

[0084] According to this embodiment, each of the first housing 50 and the second housing 60 is molded from a flexible material, and each of the side wall portion 56 of the first housing 50 and the side wall portion 66 of the second housing 60 has a flexible structure. Therefore, each of the convex portion 67 and the concave portion 57 can be easily moved by utilizing the elasticity of the housing 18. However, the present invention is not limited to this. For example, only one of the convex portion 67 and the concave portion 57 may be movable by utilizing the elasticity of the housing 18. That is, at least one of the convex portion 67 and the concave portion 57 may be movable by utilizing the elasticity of the housing 18.

[0085] Each of the first engaging portion 57 and the second engaging portion 67 in this embodiment has the above-mentioned structure. However, the present invention is not limited to this. For example, each of the first engaging portions 57 may be a convex portion formed on the first outer peripheral portion 54, and each of the second engaging portions 67 may be a concave portion provided on the second outer peripheral portion 64. In this case, each of the first engaging portions 57 may protrude inwardly of the XY plane. Each of the first engaging portions 57 and the second engaging portions 67 formed as described above functions in the same manner as in this embodiment. However, from the viewpoint of easily forming the first engaging portions 57 and the second engaging portions 67, this embodiment is preferable.

[0086] The bus bar 70 of this embodiment will be described below.

[0087] 9, bus bars 70 in this embodiment have the same shape. More specifically, each of bus bars 70 is a U-shaped round metal bar. However, the present invention is not limited to this. For example, bus bars 70 may have different shapes.

[0088] Each bus bar 70 of the present embodiment has an inner held portion 72, an outer held portion 74, and a connecting portion 76. The inner held portion 72 and the outer held portion 74 each extend in the up-down direction. The connecting portion 76 connects the upper end of the inner held portion 72 and the upper end of the outer held portion 74 to each other in a direction perpendicular to the up-down direction. The lower end of the inner held portion 72 and the lower end of the outer held portion 74 are at the same position as each other in the up-down direction.

[0089] 3 and 8, the housing 18 of this embodiment is formed with eight inner retaining holes 532 and eight outer retaining holes 552. More specifically, according to this embodiment, the inner periphery 53 of the first housing 50 is formed with eight inner retaining holes 532 and four hole portions 534, and each of the protruding portions 55 of the first housing 50 is formed with two outer retaining holes 552. Each of the inner retaining holes 532 penetrates the inner periphery 53 in the vertical direction. Each of the hole portions 534 is a hole with a ceiling and opens downward. Each of the outer retaining holes 552 penetrates the protruding portion 55 in the vertical direction.

[0090] The eight inner holding holes 532 and the four hole portions 534 are arranged concentrically around the center hole 51. The four hole portions 534 are arranged at 90° intervals around the center hole 51 in the XY plane. In the circumferential direction of a virtual circle centered on the center hole 51, the two inner holding holes 532 are located between the two hole portions 534 that are 90° apart. By providing the hole portions 534, which are holes with a ceiling, the weight of the first housing 50 can be reduced. In addition, deformation during molding caused by uneven thickness of the portion of the inner circumferential portion 53 located around the inner holding hole 532 can be suppressed, and this makes it easier to make the size of the inner circumferential portion 53 in the vertical direction uniform. However, the present invention is not limited to this, and the hole portions 534 may be provided as necessary.

[0091] Two inner retaining holes 532 are located between each of the overhanging portions 55 and the central hole 51. With this arrangement, eight retaining hole pairs 18P are formed in the housing 18. Each retaining hole pair 18P consists of one of the eight inner retaining holes 532 and an outer retaining hole 552 located closest to the inner retaining hole 532 in the XY plane.

[0092] 2, each of the bus bars 70 is held by one of the retaining hole pairs 18P. More specifically, in each of the bus bars 70, the inner retained portion 72 is received and held in the inner retaining hole 532, and the outer retained portion 74 is received and held in the outer retaining hole 552. Also, in FIG. 3 together with FIG. 6, in each of the bus bars 70, the connecting portion 76 is located on the protrusion 582 of the housing 18 and is spaced upward from the upper surface 58 of the housing 18. Each of the bus bars 70 is prone to generate heat due to the high density current flowing therein. On the other hand, according to the above-mentioned arrangement, the heat transferred from the bus bar 70 to the housing 18 can be reduced. In addition, the influence of the high density current generated inside the bus bar 70 on members such as the shield case 30 (see FIG. 4) can be reduced.

[0093] Each of the protrusions 582 in this embodiment has a narrow ring shape in the XY plane. Therefore, even if the bus bar 70 contacts the upper edge of the protrusion 582, only a small amount of heat is directly transferred to the housing 18. However, the present invention is not limited to this. For example, each of the protrusions 582 may have a small circular shape in the XY plane. Each of the bus bars 70 may be located above the protrusion 582 and away from the protrusion 582.

[0094] Referring to FIG. 4, the coned disc spring 40 is accommodated inside the housing 18 and disposed near the coil member 12 which is prone to generate heat. That is, the coned disc spring 40 is used in a high-temperature environment. For this reason, the coned disc spring 40 of this embodiment is integrally molded from a resin which is prone to elastic deformation and is resistant to thermal creep. More specifically, the coned disc spring 40 of this embodiment is molded from any one of resins POM (polyacetal), LCP (liquid crystal polymer) and PEEK (polyether ether ketone). For this reason, the coned disc spring 40 is easy to process and is prone to elastic deformation even when placed in a high-temperature environment. However, the present invention is not limited thereto. For example, the coned disc spring 40 may be made of a metal such as stainless steel. That is, it is preferable that the coned disc spring 40 of this embodiment is made of a metal or any one of resins POM, LCP and PEEK.

[0095] According to this embodiment, the coned disc spring 40 is provided, so that it is possible to reliably increase the distance between the bus bar 70 and the coil member 12. In addition, by providing the coned disc spring 40, a space can be formed above the shielding case 30, which makes it possible to reduce the heat conduction from the bus bar 70 to the coil member 12. That is, the coned disc spring 40 of this embodiment also functions as a heat countermeasure member.

[0096] 1 and 2, a central hole 51 is formed in the housing 18 of this embodiment. Referring to FIG. 9, each of the members accommodated in the housing 18 has a ring shape corresponding to the central hole 51. According to this embodiment, heat generated inside the current sensor 10 can be easily dissipated through the central hole 51. However, the present invention is not limited to this. For example, the housing 18 does not need to have the central hole 51. In this case, for example, the disc spring 40 may have a shape without the central hole 42.

[0097] 1, as already described, the current sensor 10 of the present embodiment detects a primary current flowing through the bus bar 70. However, the present invention is not limited to this. For example, the current sensor 10 may detect a primary current flowing through an electric wire passing through the central hole 51. In this case, it is not necessary to provide the bus bar 70. [Explanation of symbols]

[0098] 10 Current Sensor 12 Coil material 18 Housing 18P Retaining hole pair 19 Storage section 20 cores 22 Core Case 24 Core cover 26 Coil 27 Winding section 28 End 30 Shielding case 30U upper shield case 30L Lower Shield Case 32 Center hole 34 Inner circumference 36 Outer periphery 37U Upper protective tape 37L Lower protective tape 38U top 38L bottom surface 39 Coil member storage section 39U upper space 39L lower space 40 Disc spring 42 Center hole 44 Inner spring part 46 Outer spring part 47 Slit 48 Spring piece 50 First housing (upper housing) 51 Center hole 52 Inner wall 53 Inner circumference 532 Inner holding hole 534 Hole 54 First outer periphery 55 Overhang 552 Outer retaining hole 56 Side wall 57 First engagement portion (recess) 58 Top 582 Protrusion 59 Upper storage section 60 Second housing (lower housing) 61 Center hole 62 Inner wall 64 Second outer periphery 65 Front wall 66 Side wall 67 Second engagement portion (convex portion) 68 Bottom side 69 Lower storage section 70 Busbar 72 Inner held part 74 Outer held part 76 Connecting part 78 Terminals 80 Circuit Board

Claims

1. A current sensor including a coil member, a shield case, a housing, and a disc spring, The coil member includes a core and a coil. the core has a toroidal shape, The coil has a winding portion, The winding portion is wound around the core, The core and the winding portion are housed in the shield case, The housing includes a first housing and a second housing, the first housing and the second housing are combined with each other in a vertical direction to form the housing, The first housing has a first engagement portion, The second housing has a second engagement portion, the first engagement portion and the second engagement portion are engaged with each other, the shield case and the disc spring are accommodated in the housing, the disc spring applies pressure to the shield case in a predetermined direction along the up-down direction, whereby the shield case is pressed against the second housing in the predetermined direction, the disc spring presses the first housing in a direction opposite to the predetermined direction, whereby the first housing is pressed away from the second housing; The first engaging portion and the second engaging portion are pressed against each other in the up-down direction by the pressure of the shield case and the first housing by the disc spring, thereby maintaining the combination of the first housing and the second housing. Current sensor.

2. 2. The current sensor according to claim 1, The shield case includes an upper shield case and a lower shield case, the upper shield case is an upper member of the shield case, the lower shield case is a lower member of the shield case, the second housing is located below the lower shield case, the lower shield case is fixed to the second housing, the first housing is located above the upper shield case, The disc spring is located between the first housing and the upper shield case in the vertical direction. Current sensor.

3. 2. The current sensor according to claim 1, The current sensor includes a bus bar. the bus bar has an inner held portion, an outer held portion, and a connecting portion, The inner held portion and the outer held portion each extend along the up-down direction, The connecting portion connects an upper end of the inner held portion and an upper end of the outer held portion to each other in a direction perpendicular to the up-down direction, The housing has an inner retaining hole and an outer retaining hole formed therein, The inner retained portion is received and retained in the inner retaining hole, The outer held portion is received and held in the outer holding hole, The housing has a protrusion, The protrusion protrudes upward from an upper surface of the housing, The connecting portion is located on the protrusion and is spaced upward from the upper surface of the housing. Current sensor.

4. 2. The current sensor according to claim 1, The shield case includes an upper shield case and a lower shield case, the upper shield case is an upper member of the shield case, the lower shield case is a lower member of the shield case, The disc spring has an inner spring portion and an outer spring portion, the inner spring portion is located on an inner periphery of the disc spring in a horizontal plane perpendicular to the up-down direction and presses the shield case in the predetermined direction, the outer spring portion is located on an outer periphery of the disc spring in the horizontal plane and presses the first housing in the opposite direction, The upper shield case and the lower shield case abut against each other on the inner periphery in the horizontal plane, and face each other at a distance above and below on the outer periphery in the horizontal plane. Current sensor.

5. 5. The current sensor according to claim 4, the first engagement portion is located on an outer periphery of the first housing in the horizontal plane, The second engagement portion is located on an outer periphery of the second housing in the horizontal plane. Current sensor.

6. 6. The current sensor according to claim 5, The first housing has a first outer periphery, the first outer periphery is located on an outer periphery of the first housing in the horizontal plane, the first engagement portion is a recess formed in the first outer circumferential portion and is open in the horizontal plane; The second housing has a second outer periphery, the second outer periphery is located on an outer periphery of the second housing in the horizontal plane, the second engagement portion is a protrusion provided on the second outer circumferential portion and protrudes outwardly from the horizontal plane, At least one of the protrusion and the recess is movable by utilizing the elasticity of the housing, The protrusion is received in the recess, The lower inner wall surface of the recess and the lower surface of the protrusion are pressed against each other in the up-down direction. Current sensor.

7. 2. The current sensor according to claim 1, The disc spring has two or more slits formed therein, Each of the slits extends from a center of the disc spring in a horizontal plane perpendicular to the up-down direction toward an outside of the horizontal plane. Current sensor.

8. 2. The current sensor according to claim 1, The disc spring is made of metal or any one of the following resins: POM (polyacetal), LCP (liquid crystal polymer), and PEEK (polyether ether ketone). Current sensor.

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