JP6338944B2 - Magnetic core holder for power distribution equipment - Google Patents

Description

  The present invention relates to a magnetic core holder of a power distribution device that holds a magnetic core that detects a current to be measured flowing in a current line.

  Conventionally, a magnetic core made of a magnetic material has been used as a means for measuring current. The magnetic core is placed around a conductor through which a current to be measured flows, and a magnetic sensor such as a Hall element or a coil is disposed in an air gap formed between both ends of the magnetic core. Magnetism corresponding to the current to be measured is stably supplied from the magnetic core to the magnetic sensor, and when this magnetism is detected by the magnetic sensor, the current to be measured flowing through the conductor is measured.

  Magnetic sensors are often mounted on a printed wiring board due to the rationality of sensor wiring, and the direction of magnetic detection may be perpendicular to the board mounting surface or horizontal. When detecting magnetism in the direction horizontal to the board mounting surface, for example, as shown in FIG. 1, the magnetic core 2 and the lead-type component shape are formed on the printed wiring board 1 in which the opening 1a through which the current line is inserted is formed. The magnetic sensor 3 is mounted. FIG. 2A is a plan view showing a state in which these components are mounted on the printed wiring board 1, FIG. 2B is a front view, and FIG. 2C is a side view in which the magnetic core 2 is broken. In the lead type magnetic sensor 3, the magnetic detection center 3 a exists at a relatively high position from the substrate surface of the printed wiring board 1. For this reason, the mounting height of the magnetic core 2 is raised by the lead pin 4 so that the magnetic detection center 3a of the lead type magnetic sensor 3 is positioned at the center of the air gap 2a formed between both ends of the magnetic core 2. Is set.

  Thus, when detecting the magnetism of the direction parallel to the board | substrate mounting surface of the magnetic sensor 3, for example, in the electronic watt-hour meter which is a kind of electric power distribution apparatus, the structure of a current detection part is shown in FIG. The partially broken side view and the configuration of the voltage detector are shown in the partially broken side view of FIG.

  The electronic watt-hour meter calculates the amount of power used by multiplying the measured current and voltage by an electronic circuit. The main printed wiring board 5 on which the electronic circuit is formed is supported by an internal structure support 6. Thus, it is located away from the bottom of the instrument on the lower side of the figure and is parallel to the bottom of the instrument. On the main printed wiring board 5, a liquid crystal display device 7 for displaying the amount of power used calculated by an electronic circuit is mounted in the vicinity of the front side of the instrument on the upper side of the figure. In addition, a switch 8 for cutting off and supplying power is supported by the internal structure support 6 below the main printed circuit board 5. A current line 9 through which the current to be measured flows is drawn into the switch 8 as shown in FIG.

  As described above, since the liquid crystal display device 7 is located near the front surface of the instrument and the current line 9 is located near the bottom surface of the instrument, there is a physical distance between the main printed wiring board 5 and the current line 9. For this reason, it is difficult to mount the magnetic sensor 3 and the like for detecting the current flowing through the current line 9 on the main printed wiring board 5. Therefore, the sub printed wiring board 1 on which the magnetic sensor 3 and the like are mounted is provided separately from the main printed wiring board 5, and the sub printed wiring board 1 and the main printed wiring board 5 are connected via the lead wires 11 and the connectors 12. Connected. The magnetic core 2 is disposed so as to surround the current line 9, and the magnetic sensor 3 is positioned in the air gap 2a as described above. Further, a voltage for power calculation or the like is taken from the voltage line 13 shown in FIG. 4B. This voltage is also connected to one end of the lead wire 14 with a screw terminal or a socket terminal. Measurement is performed by connecting the end to the main printed wiring board 5 with the connector 15.

  On the other hand, when detecting magnetism in a direction perpendicular to the board mounting surface, as shown in FIG. 3, a magnetic sensor 22 having a chip-type component shape is mounted on the printed wiring board 21. The printed wiring board 21 is disposed in the air gap 23 a of the magnetic core 23. FIG. 4A is a plan view of a state where the magnetic sensor 22 mounting portion of the printed wiring board 21 is sandwiched between the air gaps 23a of the magnetic core 23, FIG. 4B is a front view, and FIG. FIG. In this case, the merit of mounting the magnetic core 23 on the printed wiring board 21 is small, and the printed wiring board 21 on which the magnetic sensor 22 is mounted and the magnetic core 23 are separated and fixed to the device as shown in FIG. . A current line (not shown) through which the current to be measured flows is inserted into the magnetic core 23.

  When a particularly small current value is measured by the magnetic sensors 3 and 22 or the like, the magnetic cores 2 and 23 become floating conductors and are affected by a voltage different from the current line inserted through the magnetic cores 2 and 23. In some cases, the current measurement cannot be performed stably, and the magnetic cores 2 and 23 must be connected to the ground. In such a case, as shown in FIG. 1, in the structure in which the magnetic core 2 with the lead pins 4 is mounted on the printed wiring board 1, the magnetic core is interposed via the lead pins 4 and the wiring pattern formed on the printed wiring board 1. It is relatively easy to connect 2 to ground. However, as shown in FIG. 3, in a structure in which the magnetic core 23 is not mounted on the printed wiring board 21, a separate ground connection structure is required.

  For this reason, conventionally, in Patent Document 1, an elastic conductor in the form of a leaf spring clip is mounted on a printed wiring board, and the elastic conductor is brought into contact with an end face facing the gap of the magnetic core so that the magnetic core and the printed wiring board are A structure has been proposed in which the ground pattern is electrically connected. Further, Patent Document 2 proposes a structure in which a magnetic core and a ground pattern on a printed wiring board are connected with a conductive adhesive so that they are electrically connected. Also, a structure in which one end of a lead wire is soldered to the magnetic core and the other end of the lead wire is connected to a ground phase voltage line is also conceivable.

JP 2011-169843 A JP-A-9-127159

  However, in the ground connection structure using the elastic conductor disclosed in Patent Document 1, the dimension between the magnetic sensor mounted on the printed wiring board and the magnetic core in the gap of the magnetic core is determined by the elastic force of the elastic conductor. It may change and is not preferable. In addition, the ground connection structure using the conductive adhesive disclosed in Patent Document 2 applies an appropriate amount of adhesive in a narrow space between the ground pattern on the printed wiring board and the magnetic core. The adhesive may adhere to unnecessary portions, which is not preferable. Moreover, since the hardening time of an adhesive agent is also needed, the lead time in a manufacturing process also becomes long. In addition, a ground connection structure using a lead wire is not preferable because the number of steps for connecting to each location increases and the manufacturing cost increases.

  The present invention has been made to solve such a problem. A current line through which a current to be measured flows is inserted so as to surround the current line, and the current to be measured is surrounded by the cylindrical part. A magnetic core housing part that houses a magnetic core that generates magnetism according to the flow, an insertion hole through which the voltage line is inserted, a first gap part that communicates with the magnetic core accommodation part, and a second gap part that communicates with the insertion hole are formed. And a connecting conductor receiving portion for receiving a connecting conductor that contacts the magnetic core accommodated in the magnetic core accommodating portion via the first gap portion and contacts the voltage line inserted through the insertion hole via the second gap portion. The magnetic core holder of the power distribution device was configured.

  According to this configuration, the current line through which the current to be measured flows is inserted into the cylindrical part, and the magnetic core is accommodated in the magnetic core accommodating part, so that the magnetic core is separated from the current line by the cylindrical part. While being separated, the current line is surrounded and held by the magnetic core holder. Further, the connection conductor is accommodated in the connection conductor accommodating portion, and a voltage line different from the current line is inserted into the insertion hole, so that the connection conductor comes into contact with the magnetic core through the first gap portion and the second The magnetic core is in contact with the voltage line through the gap, and the magnetic core is electrically connected to the voltage line through the connection conductor, and is in conduction with the voltage line. Further, the current line and the voltage line are insulated and separated from each other and are held by the magnetic core holder.

  Therefore, if the voltage line is of the ground phase, the magnetic core is grounded via the connection conductor. For this reason, the magnetic core is grounded simply by accommodating the magnetic core in the magnetic core housing portion, the connecting conductor in the connecting conductor housing portion, and inserting the voltage wire through the insertion hole without using a lead wire as in the prior art. It becomes possible to connect to. Therefore, the magnetic core can be connected to the ground at a low cost without increasing the number of connection steps.

The present invention also provides:
Both ends of the magnetic core are separated in a direction parallel to the direction in which the current to be measured flows, and an air gap is formed between the both ends to generate magnetism in a direction parallel to the direction in which the current to be measured flows.
One end of a printed wiring board on which a magnetic sensor for detecting magnetism is mounted is inserted to position the magnetic sensor in the air gap, and the notch provided in communication with the air gap is sandwiched between the air gaps. It is provided in a core holder.

  According to this configuration, the one end of the printed wiring board is inserted into the notch of the magnetic core holder, so that the magnetic sensor mounted on the printed wiring board is formed between the both ends of the magnetic core. Positioned in the gap and fixed. Therefore, the relative position between the magnetic sensor and the magnetic core mounted on the printed wiring board is held unchanged by the magnetic core holder. Therefore, unlike the conventional structure in which the magnetic core is grounded via the elastic conductor, there is no possibility that the dimension between the magnetic sensor and the magnetic core changes, and the magnetism corresponding to the current to be measured is stabilized by the magnetic sensor. It is possible to accurately measure the current to be measured. In addition, unlike the conventional structure in which adhesive is applied to the narrow space between the earth pattern and the magnetic core, there is no concern that the adhesive will adhere to unnecessary parts, and the lead in the manufacturing process depends on the curing time of the adhesive. The time does not increase. As a result, the magnetic core incorporated in the power distribution device can be easily connected to the ground without adversely affecting the device performance of the power distribution device and without increasing the lead time.

  Further, the present invention is characterized in that a bent portion having elasticity and having an end portion floating is formed on the connection conductor, and the bent portion contacts the voltage line with a predetermined contact pressure through the second gap portion. .

  According to this configuration, since the connecting conductor contacts the voltage line with a predetermined contact pressure by the bent portion, the connecting conductor is stably connected to the voltage line, and the ground state of the magnetic core is stably maintained.

  According to the present invention, it is possible to connect the magnetic core to the ground simply by allowing the magnetic core to be accommodated in the magnetic core accommodating portion, the connecting conductor to be accommodated in the connecting conductor accommodating portion, and the voltage line to be inserted into the insertion hole. The magnetic core can be connected to the ground inexpensively without increasing the number of steps. Further, the magnetic core incorporated in the power distribution device can be easily connected to the ground without adversely affecting the device performance of the power distribution device and without increasing the lead time.

(A) is a plan view of a general current detection structure for measuring the current to be measured by detecting magnetism in a horizontal direction on the board mounting surface of the printed wiring board, (b) is a front view, and (c) is one. FIG. (A) is a partially broken side view of the electronic watt-hour meter provided with the current detection structure shown in FIG. 1, and (b) is a partially broken side view showing the voltage detection structure of the electronic watt-hour meter. . (A) is a plan view of a general current detection structure for measuring current to be measured by detecting magnetism in a direction perpendicular to the board mounting surface of the printed wiring board, (b) is a front view, and (c) is a side view. FIG. It is a disassembled perspective view of the electric current detection part comprised using the magnetic core holder of the electric power distribution apparatus by one embodiment of this invention. (A) is a partially broken plan view of a magnetic core assembly in which a magnetic core and a connection conductor are housed in a magnetic core holder according to an embodiment, (b) is a front view, and (c) is a connection conductor housing portion. (D) is a partially enlarged view of the connecting conductor portion shown in (c). It is an external appearance perspective view of the switch part built in the electronic watt-hour meter in which the magnetic core assembly shown in FIG. 5 was incorporated. (A) is a top view in the state where the voltage line was inserted in the insertion hole of the magnetic core holder constituting the magnetic core assembly shown in FIG. 5, (b) is a front view, and (c) is a longitudinal sectional view. is there. (A) is a partially broken side view of an electronic watt-hour meter showing the configuration of a current detector incorporating the magnetic core assembly shown in FIG. 5, and (b) is a voltage detector of the electronic watt-hour meter. It is a partially broken side view which shows the structure.

  Next, the form for implementing this invention which applied the magnetic core holder of the power distribution apparatus by this invention to the magnetic core holder of an electronic watt-hour meter is demonstrated.

  FIG. 4 is an exploded perspective view of the current detection unit of the single-phase three-wire electronic watt-hour meter configured using the magnetic core holder 31 according to the embodiment of the present invention.

  The current detector of the electronic watt-hour meter is mounted on the magnetic core holder 31, the pair of current detection magnetic cores 32 and 32 and the connection conductor 33, and the printed wiring board 34 accommodated in the magnetic core holder 31. A pair of magnetic sensors 35, 35 and a printed wiring board holding mechanism (described later) that holds the printed wiring board 34 are provided. In this current detector, the current to be measured flowing through the current lines 36 and 36 is converted into magnetism corresponding to the magnitude by the magnetic cores 32 and 32 and detected by the magnetic sensors 35 and 35. The magnetism detected by the magnetic sensors 35 and 35 is converted into a value proportional to the current flowing through the current lines 36 and 36 by an electronic circuit formed on the printed wiring board 34, and is printed from the power terminal of the electronic watt-hour meter. The amount of power is calculated by multiplying the value proportional to the voltage input to the substrate 34. A liquid crystal display 37 is mounted on the printed wiring board 34, and the calculated electric energy is displayed on the liquid crystal display 37.

  The magnetic core holder 31 is formed by molding an electrically insulating resin, and includes cylindrical portions 31a and 31a, magnetic core housing portions 31b and 31b, insertion holes 31c, and connection conductor housing portions 31d. Current lines 36 and 36 through which the current to be measured flows are inserted into the cylindrical parts 31 a and 31 a, and the cylindrical parts 31 a and 31 a surround the current lines 36 and 36. A voltage line 39 (see FIG. 6) to be described later is inserted through the insertion hole 31c. The magnetic core housing portions 31b and 31b accommodate the magnetic cores 32 and 32, and the connection conductor housing portion 31d accommodates the connection conductor 33.

  The magnetic cores 32 and 32 are fixed to the vertical surface 31b1 and the horizontal surface 31b2 forming the magnetic core accommodating portions 31b and 31b with an adhesive, and are accommodated in the magnetic core accommodating portions 31b and 31b, and surround the cylindrical portions 31a and 31a. To generate magnetism corresponding to the flow of the current to be measured. The magnetic cores 32 and 32 have both end portions 32a and 32a extending a predetermined length in a direction B crossing the direction A in which the current to be measured flows, and spaced apart in a horizontal direction C parallel to the direction A in which the current to be measured flows. The air gap 32b is formed by facing each other. When the current to be measured flows through the current lines 36 and 36, the magnetic cores 32 and 32 generate magnetism corresponding to the flow of the current to be measured in the horizontal direction C in the air gap 32b formed between both ends 32a and 32a. Let

  In the present embodiment, the magnetic cores 32 and 32 are formed by laminating a plurality of metal plate-like components such as a plurality of soft magnetic plates punched and pressed into an L shape. However, the magnetic cores 32 and 32 having such a shape can be obtained by bending and pressing a single metal plate-shaped part, baking a powdered sintered material, or powdered solid material. Even if it is compacted or metal powder is injection molded, it is formed in the same way.

  Further, the magnetic core holder 31 is provided with a total of four groove-shaped notches 31e at positions that communicate with the air gaps 32b and sandwich the air gaps 32b. A lower end 34 a of the printed wiring board 34 is inserted into each notch 31 e, and each notch 31 e holds the lower end 34 a of the printed wiring board 34. Further, an instrument support 44 (see FIG. 8), which will be described later, that supports the magnetic core holder 31 is provided with a groove into which both end portions 34b and 34b of the printed wiring board 1 are inserted, and a printed wiring inserted into the groove. A latch portion for fixing the substrate 34 is provided. The latch portion has a structure that prevents the printed wiring board 34 from coming out of the groove unless it is released. The notches 31e provided in the magnetic core holder 31 and the grooves and latches provided in the instrument support 44 are printed in a state where the magnetic sensors 35 and 35 are located in the air gaps 32b and 32b. A printed wiring board holding mechanism for holding the wiring board 34 is configured. This printed wiring board holding mechanism holds the printed wiring board 34 in a positional relationship in which the center positions of the air gaps 32b and 32b and the detection centers of the magnetic sensors 35 and 35 coincide.

  5A is a partially broken plan view of the magnetic core assembly 41 in which the magnetic cores 32 and 32 and the connection conductors 33 are accommodated in the magnetic core holder 31, FIG. 5B is a front view, and FIG. c) is a longitudinal sectional view of the connection conductor accommodating portion 31d, and FIG. 10 (d) is a partially enlarged view of the connection conductor 33 portion shown in FIG. In the figure, the same parts as those in FIG.

  The connection conductor housing portion 31d is formed with slit-shaped first gap portions 31d1, 31d communicating with the magnetic core housing portions 31b, 31b and a second gap portion 31d2 communicating with the insertion hole 31c. Further, a claw 31f is formed in the magnetic core holder 31 at the back of the connection conductor housing portion 31d. The connecting conductor 33 is made of a copper alloy thin plate material having elasticity, and by pressing, an arc-shaped bent portion 33a is formed to protrude from the upper surface side at the center portion of the thin plate material, and the end portions 33b and 33b are thin. Projecting on both sides of the plate. The bent portion 33a has a cantilevered bending beam shape, and has one end portion that is elastic and elastic. Further, a frame portion 33c is formed at a portion where the bent portion 33a of the connection conductor 33 is removed.

  The connection conductor 33 has its end portions 33b and 33b inserted into the first gap portions 31d1 and 31d of the magnetic core holder 31 and pushed into the connection conductor housing portion 31d, so that the tip of the frame portion 33c is hooked. It comes into contact with 31f and bends, gets over the claw 31f, and fits into the claw 31f as shown in FIGS. The width dimension of the connection conductor 33 is set larger than the distance L between the two magnetic cores 32 and 32 shown in FIG. Therefore, in the process in which the connection conductor 33 is accommodated in the connection conductor accommodating portion 31d as described above, the end portions 33b and 33b protrude into the magnetic core accommodating portions 31b and 31b via the first gap portions 31d1 and 31d, It interferes with the grooves 32c and 32c formed on the respective side portions of the magnetic cores 32 and 32 accommodated in the magnetic core accommodating portions 31b and 31b. However, the connection conductor 33 is bent in the width direction by the set amount of bending due to its elasticity, and is held in the connection conductor housing portion 31d while holding the set stress, and the end portions 33b and 33b are connected to the magnetic cores 32, respectively. , 32 and the same potential as the magnetic cores 32, 32. At this time, in the connection conductor 33, the arc-shaped portion of the bent portion 33a projects into the insertion hole 31c through the second gap portion 31d2 as shown in FIGS.

  FIG. 6 is an external perspective view showing a state in which the magnetic core assembly 41 is incorporated in the switch 42 built in the electronic watt-hour meter 43 (see FIG. 8), as will be described later. In the figure, the same parts as those in FIGS. 4 and 5 are denoted by the same reference numerals, and the description thereof is omitted.

  The switch 42 is provided between the current lines 36 and 36 connected to the load terminals 1L and 3L of the single-phase three-wire electronic watt-hour meter and the current lines 38 and 38 connected to the power supply terminals 1S and 3S. The connection is opened and closed, and the power supply to the load connected to the load terminals 1L, 2L, and 3L is interrupted. The voltage line 39 is connected to the load terminal 2L, and is connected to a neutral line which is a single-phase three-wire ground phase. This neutral wire is a terminal block (not shown) provided separately from the watt hour meter, and is short-circuited to the power supply terminal 2S. A current supplied to the load flows through the current lines 36, 36, 38, and 38, and this current is detected by the magnetic cores 32 and 32 through which the current lines 36 and 36 are inserted. Further, the voltage of the neutral line is detected from the standing portion 39a of the voltage line 39, and the voltage of the voltage line of the single-phase three-wire is detected from the protruding portions 38a and 38a of the current lines 38 and 38.

  The voltage line 39 is formed by vertically bending a standing portion 39a on the side opposite to the side connected to the load terminal 2L. The standing portion 39a is inserted into the insertion hole 31c of the magnetic core holder 31, and the lower end portion 34a of the printed wiring board 34 is inserted into the gap to detect the neutral line voltage formed on the printed wiring board 34. Contact the wiring pattern.

  7A is a plan view of a state in which the standing portion 39a is inserted into the insertion hole 31c of the magnetic core holder 31, FIG. 7B is a front view, and FIG. 7C is a longitudinal sectional view. . In the figure, the same parts as those in FIGS. 4 to 6 are denoted by the same reference numerals, and the description thereof is omitted.

  As described above, since the bent portion 33a of the connection conductor 33 protrudes through the second gap portion 31d2 in the insertion hole 31c, the standing portion 39a is inserted into the insertion hole 31c of the magnetic core holder 31. As shown in FIG. 5C, the lower surface of the standing portion 39a pushes down the arc-shaped portion of the bent portion 33a protruding into the insertion hole 31c. At this time, the bent portion 33a having a cantilever-shaped bent beam shape is bent in a vertical direction by a set amount, and holds the set stress. For this reason, the connection conductor 33 comes into contact with the voltage line 39 with a predetermined contact pressure via the second gap portion 31d2, and has the same potential as the voltage line 39.

  FIG. 8A is a partially broken side view of the electronic watt-hour meter 43 showing the configuration of the current detection unit in which the magnetic core assembly 41 shown in FIG. 5 is incorporated, and FIG. It is a partially broken side view which shows the structure of the voltage detection part of a total of 43. FIG. In the figure, the same parts as those in FIGS. 4 to 6 are denoted by the same reference numerals, and the description thereof is omitted.

  The printed wiring board 34 on which an electronic circuit for calculating the amount of power used is formed is supported vertically by the grooves and latch portions provided on the instrument support 44 as described above, and is installed vertically on the instrument bottom surface. The liquid crystal display device 37 mounted on the printed wiring board 34 is arranged with its display surface facing the window 43a on the front surface of the instrument. Below the instrument support 44, a switch 42 shown in FIG. A current line 36 through which the current to be measured flows is drawn into the switch 42 as shown in FIG. The magnetic sensor 35 mounted on the printed wiring board 34 is positioned in an air gap 32 b formed between both ends of the magnetic core 32.

  A voltage line voltage is taken from the current line 38 shown in FIG. 5B for power calculation and the like, and this voltage is printed in the gap of the protruding portion 38a formed to protrude from the vertical bent portion of the current line 38. Measurement is performed by inserting the lower end 34 a of the wiring board 34 and making contact with the voltage line voltage detection wiring pattern formed on the printed wiring board 34.

  According to the magnetic core holder 31 of the electronic watt hour meter 43 according to this embodiment, the current lines 36 and 36 through which the current to be measured flows are inserted into the cylindrical portions 31a and 31a, and the magnetic cores 32 and 32 are inserted. Are accommodated in the magnetic core accommodating portions 31b and 31b. The magnetic cores 32 and 32 are housed in the magnetic core housing portions 31b and 31b as described above, so that the current wires 36 and 36 are separated from the current wires 36 and 36 by being separated from the cylindrical portions 31a and 31a. And is held by the magnetic core holder 31. Further, the connection conductor 33 is accommodated in the connection conductor accommodating portion 31d as shown in FIG. 5, and the standing portion 39a of the voltage line 39 different from the current lines 36 and 36 is formed in the insertion hole 31c as shown in FIG. Is inserted. Since the connection conductor 33 is housed in the connection conductor housing portion 31d in this way, the connection conductor 33 contacts the magnetic cores 32 and 32 via the first gap portions 31d1 and 31d1, and the voltage line via the second gap portion 31d2. 39 is contacted. Therefore, the magnetic cores 32 and 32 are electrically connected to the voltage line 39 via the connection conductor 33 and are electrically connected to the voltage line 39. Further, the current lines 36 and 36 and the voltage line 39 are insulated and separated from each other and are held by the magnetic core holder 31.

  Therefore, if the voltage line 39 is of the ground phase as in this embodiment, the magnetic cores 32 and 32 are grounded via the connection conductor 33. Therefore, the magnetic cores 32 and 32 are simply accommodated in the magnetic core accommodating portions 31b and 31b, the connection conductor 33 is accommodated in the connection conductor accommodating portion 31d, and the voltage line 39 is inserted into the insertion hole 31c without using a lead wire as in the conventional case. It is possible to connect the magnetic cores 32 and 32 to the ground simply by inserting them into the ground. Therefore, the magnetic cores 32 and 32 can be connected to the ground inexpensively without increasing the number of connection steps.

  Further, according to the magnetic core holder 31 of the electronic watt-hour meter 43 according to the present embodiment, printing is performed by inserting the lower end portion 34a of the printed wiring board 34 into the cutout portion 31e of the magnetic core holder 31. The magnetic sensors 35 and 35 mounted on the wiring board 34 are positioned and fixed in an air gap 32b formed between both end portions 32a of the magnetic cores 32 and 32, as shown in FIG. . Therefore, the relative position between the magnetic sensors 35 and 35 and the magnetic cores 32 and 32 mounted on the printed wiring board 34 is held unchanged by the magnetic core holder 31.

  For this reason, the dimension between the magnetic sensor and the magnetic core changes as in the conventional ground connection structure disclosed in Patent Document 1 in which the magnetic core is grounded via an elastic conductor having a leaf spring clip shape. There is no such thing, and the magnetism corresponding to the current to be measured can be stably detected by the magnetic sensors 35 and 35 so that the current to be measured flowing through the current lines 36 and 36 can be accurately measured. Moreover, there is no concern that the adhesive adheres to unnecessary portions, as in the conventional ground connection structure disclosed in Patent Document 2, in which an adhesive is applied to a narrow space between the ground pattern and the magnetic core, The lead time in the manufacturing process does not become longer due to the curing time of the adhesive. As a result, the magnetic cores 32 and 32 incorporated in the electronic watt-hour meter 43 can be easily connected to the ground without adversely affecting the device performance of the electronic watt-hour meter 43 and without increasing the lead time. It becomes possible to do.

  Further, according to the magnetic core holder 31 of the electronic watt hour meter 43 according to the present embodiment, the connecting conductor 33 has a predetermined contact pressure on the voltage line 39 by the bent portion 33a as shown in FIG. Contact. For this reason, the connection conductor 33 is stably connected to the voltage line 39, and the ground state of the magnetic cores 32 and 32 is stably maintained.

  Further, as in the present embodiment, the electronic watt-hour meter 43 that detects the magnetism in the direction perpendicular to the board mounting surface of the magnetic sensors 35, 35 generates the magnetism in the direction parallel to the board mounting surface of the magnetic sensor 3. Compared with the conventional electronic watt-hour meter shown in FIG. 2, the material costs of the lead wires 11 and 14 and the connectors 12 and 15 and the man-hours associated with assembling these parts do not occur, so that they can be manufactured at low cost. it can.

  In the above embodiment, the case where the magnetic core holder according to the present invention is applied to an electronic watt-hour meter has been described. However, the magnetic core holder according to the present invention is not limited to application to an electronic watt-hour meter, but can be similarly applied to various other power distribution devices that measure current using a magnetic core. And similar effects can be obtained.

DESCRIPTION OF SYMBOLS 31 ... Magnetic core holder 31a ... Cylindrical part 31b of magnetic core holder 31 ... Magnetic core accommodating part 31c of magnetic core holder 31 ... Insertion hole 31d of magnetic core holder 31 ... Connection conductor accommodation of magnetic core holder 31 Part 31e ... Notch 31f of magnetic core holder 31 ... Claw of magnetic core holder 31 ... Magnetic core 32a ... End of magnetic core 32 32b ... Air gap 32c of magnetic core 32 ... Groove 33 of magnetic core 32 ... Connection conductor 33a ... Bending portion of connection conductor 33 33b ... End portion of connection conductor 33 33c ... Frame portion of connection conductor 33 34 ... Printed wiring board 34a ... Lower end portion of printed wiring board 34b ... 35 ... Magnetic sensor 36, 38 ... Current line 37 ... Liquid crystal display 39 ... Voltage line 39a ... Standing part of voltage line 39 41 ... Magnetic core assembly 42 ... Switch 43 ... Electronic power Force meter 43a ... Window of electronic watt-hour meter 43 ... Meter support

Claims (3)

  A magnetic core that houses a cylindrical portion that surrounds the periphery of the current line through which a current line through which the current to be measured flows is inserted, and a magnetic core that surrounds the cylindrical portion and generates magnetism according to the flow of the current to be measured The magnetic part accommodated in the magnetic core accommodating part is formed with an accommodating part, an insertion hole through which the voltage line is inserted, a first gap part communicating with the magnetic core accommodating part, and a second gap part communicating with the insertion hole. And a connection conductor housing portion that contacts the core via the first gap portion and accommodates the connection conductor that contacts the voltage line inserted through the insertion hole via the second gap portion. Magnetic core holder for power distribution equipment. Both ends of the magnetic core are separated in a direction parallel to the direction in which the current to be measured flows, and an air gap is formed between the both ends to generate the magnetism in a direction parallel to the direction in which the current to be measured flows. ,
The magnetic core holder is inserted into one end of a printed wiring board on which a magnetic sensor for detecting the magnetism is mounted to position the magnetic sensor in the air gap. The magnetic core holder for a power distribution device according to claim 1, further comprising a notch portion provided in communication with the magnetic core.   The connection conductor is formed with a bent portion having elasticity and an end portion floating, and the bent portion contacts the voltage line with a predetermined contact pressure through the second gap portion. A magnetic core holder for a power distribution device according to claim 1.

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