JPH11121067A - Terminal board with built-in current sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure usual wiring and current detection capability while miniaturizing a terminal board with a built-in current sensor. SOLUTION: Circular cores 16u, 16v, and 16w consisting of a ferromagnetic material composing a current sensor are installed so as to enclose connecting terminals 15u, 15v, and 15w, and cross sections 19a and 19b are provided so as to detach a lid part 13a consisting of a part opposed to the connecting terminals 15u, 15v, and 15w of the components of the terminal board with a built-in current sensor which encloses the connecting terminals 15u, 15v, and 15w, from a base part 13b containing the connecting terminals of the terminal board with a built-in current sensor. Springs 21u, 21v and 21w are provided on the lid part for applying a force to the cross sections 19a and 19b in the direction contracting the distance between the cross sections 19a and 19b formed on the circular cores 16u, 16v and 16w, and magnetic shield plates 22x and 22y respectively consisting of non-magnetic and insulating substance are provided between the parts 16ub and 16vb, and 16vb and 16wb contained in the base parts of the circular cores, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal block used for electric and electronic equipment, and more particularly to a terminal block with a built-in current sensor for detecting a current in a current path connected to a terminal.

[0002]

2. Description of the Related Art Conventionally, current sensors have been widely used for controlling electric equipment. In order to perform feedback control of an AC motor based on comparison with a current command, a current sensor is provided on a current path from an inverter to the AC motor. Detecting the supplied current is performed.

[0003] On the other hand, a terminal block is for connecting a plurality of current paths together at one place, and has conventionally been used in various electric devices. For example, a terminal block between an inverter and an AC motor has been used. It is used to connect and fix roads. As described above, there is one in which the current sensor and the terminal block are provided for the same current path. In addition, in consideration of recent trends in space saving and miniaturization, those in which both are integrated, that is, Terminal block with built-in current sensor
Various proposals have been made in, for example, JP-A-0881 and JP-A-6-201737.

In the terminal blocks with a built-in current sensor disclosed in these publications, for example, as shown in FIG. 7, a conductive bracket 25 is laid on the terminal block 13, and an annular core 16 is wound around the center of the conductive bracket 25 in the wiring direction. Annular core 16 sandwiching conductive metal fitting 25
, Connection terminals 15 are provided at both ends of each of the two, and electric wiring is fixed to the connection terminals 15, respectively. Then, the current flowing through the electrical wiring is detected by detecting the current flowing through the conductive metal fitting 25.

[0005]

In the above configuration, it is necessary to provide the terminal block with conductive metal fittings in addition to the connection terminals, which limits the miniaturization of the terminal block.

[0006] The terminal block with a built-in current sensor of the present invention has been made to solve such problems, and an object of the present invention is to reduce the size of the terminal block with a built-in current sensor.

[0007] The terminal block with a built-in current sensor of the present invention comprises:
Another object is to secure the same wiring workability as in the related art while reducing the size of the terminal block with a built-in current sensor.

Further, the terminal block with a built-in current sensor of the present invention ensures the same wiring workability as before and the same accuracy of current detection as before while reducing the size of the terminal block with built-in current sensor. It is one of the purposes.

[0009]

In order to solve at least one of the above-mentioned problems, a terminal block with a built-in current sensor according to the present invention comprises a connection terminal for connecting a current path and an electric insulation provided with the connection terminal. And a ferromagnetic annular core disposed on the terminal block surrounding a current path connected to the connection terminal, and detecting a magnitude of a magnetic field generated in the annular core. A terminal block with a built-in current sensor capable of detecting a current flowing through the current path, wherein the connection terminal is arranged on an inner periphery of the annular core.

In order to solve at least one of the above-mentioned problems, a terminal block with a built-in current sensor according to a second aspect is provided.
The terminal block with a built-in current sensor according to the above, wherein the terminal block is divided into a portion covering the connection terminal and a portion to which the connection terminal is attached, and the annular core covers at least the connection terminal; It is characterized by being formed separately from the base other than the lid.

In order to solve at least one of the above problems, a terminal block with a built-in current sensor according to a third aspect is provided.
The terminal block with a built-in current sensor according to any one of the preceding claims, further comprising: a leakage magnetic flux guiding means for guiding a leakage magnetic flux from a division surface of the annular core into the annular core.

[0012] In order to solve at least one of the above problems, a terminal block with a built-in current sensor according to claim 4 is provided.
The terminal block with a built-in current sensor according to claim 1, wherein said leakage magnetic flux inducing means applies a force for reducing a distance between a surface of said divided surface on a lid side and a surface of said divided surface on a base side. It is characterized by being.

[0013] In order to solve at least one of the above problems, a terminal block with a built-in current sensor according to claim 5 is provided.
The terminal block with a built-in current sensor according to any one of the preceding claims, wherein the leakage magnetic flux inducing means is a non-magnetic and electrically insulating magnetic flux shielding means surrounding a periphery of the division surface.

[0014]

In the terminal block with a built-in current sensor according to the first aspect of the present invention, a connection terminal is provided on the inner periphery of the annular core constituting the current sensor, and current is directly detected from the connection terminal or a current path connected to the connection terminal. Do.

In the terminal block with a built-in current sensor according to the second aspect of the present invention, at the time of attachment / detachment work to the connection terminal of the current path, the annular core is provided at a portion where the terminal block covers the connection terminal and at a portion where the connection terminal is attached. It can be disassembled into a base and the lid.

In the terminal block with a built-in current sensor according to the third aspect, at the time of detecting a current, the leakage magnetic flux inducing means induces the leakage magnetic flux from the divided surface of the annular core into the annular core.

In the terminal block with a built-in current sensor according to the fourth aspect, the distance between the base-side divided surface and the lid-side divided surface is reduced by the urging means, and the magnetic flux generated in the annular core is generated from the annular core. A leaking space is less likely to be formed.

In the terminal block with a built-in current sensor according to the fifth aspect, the periphery of the divided surface is surrounded by non-magnetic and electrically insulating magnetic flux shielding means, so that it is difficult to form a space in which magnetic flux leaks from the divided surface.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. Note that the same parts as those in FIG. 7 are denoted by the same reference numerals. First, an example of the current sensor portion of the current sensor built-in terminal block of the present invention will be described with reference to FIGS.

The linearly extending current path 1 is provided with an annular core 2 surrounding the current path 1. The annular core 2 is made of an annularly formed ferromagnetic material and is separated at one point in the circumferential direction. A gap (gap) 4 is formed between the separated ends 3a and 3b. The Hall element 5 is provided in the gap 4 and is driven by supplying a control current from the drive circuit 6.

FIG. 2 shows an example of the driving circuit, wherein 7 to 9 are resistors, 10 is an operational amplifier (operational amplifier), and a non-inverting input terminal (+) is a connection point between the resistors 7 and 8. A, and a Hall element 5 is connected between the inverted input terminal (−) and the output terminal. The operational amplifier 10 is supplied with power of +15 (V) and −15 (V). The control current I _H is supplied to the Hall element 5 in advance by the drive circuit configured as described above.

Returning to FIG. 1, the current to be measured I flows through the current path 1, and a magnetic field proportional to the current to be measured I is generated through the annular core. Accordingly, a voltage proportional to the product of the generated magnetic field and the control current I _H , that is, the product of the measured current I and the control current I _H is applied to the Hall element 5 disposed between the cut ends 3 a and 3 b of the annular core. An output voltage VH proportional to the output voltage _VH is generated, and can be taken out from the output lead 11.

The output voltage V _H taken out of the output lead 11 is input to the arithmetic unit 12 and the output voltage V _H is applied to the flat current path 1.
Is calculated. Since the magnetic permeability of the annular core 2 is much larger than the magnetic permeability of the gap, the magnetic flux density Bg in the gap 4 can be approximated by the following equation 1.

[0024]

[Formula 1] Bg = μ ₀ · I / 1

Here, μ ₀ is the magnetic permeability of the gap, l is the gap length, and I is the measured current flowing through the current path. The output voltage V _H of the Hall element 5 is expressed by the following equation (2).

[0026]

[Equation 2] V _H = R _H / d · I _H · Bg

Here, R _H is a Hall coefficient, d is the thickness of the Hall element 5, and I _H is a control current. Thus, the arithmetic unit of the formula 1, to calculate the current to be measured I than the output voltage V _H using Equation 2.

FIG. 3 is a longitudinal sectional view of a terminal block with a built-in three-phase three-wire current sensor according to the present invention, and FIG. 4 is a sectional view of a terminal block with a built-in three-phase three-wire current sensor according to the present invention. Perspective views showing the whole are shown respectively. The terminal block 13 of the current sensor built-in terminal block is made of plastic which is an electrically insulating material. The terminal block 13 has three holes 14u, 14v, 14w penetrating therethrough in the wiring direction, and the holes 14u, 14v, 14w have connection terminals 1 respectively.
5u, 15v, 15w are provided, and three holes 14u, 1
Annular cores 16u, 16w made of ferromagnetic directional silicon steel plate are embedded so as to be wound around two ends 14u, 14w at both ends of 4v, 14w.
The annular cores 16u, 16w are partially cut away to form a U-shaped cross section, and the notched portions 17u, 17w are Hall elements as detecting means for detecting the magnitude of the magnetic field in the annular cores 16u, 16w. 18u and 18w are inserted. A drive current is supplied to the Hall elements 18u and 18w by a drive circuit (not shown), and the hall elements 18u and 18w are driven, and output an electric signal to an arithmetic unit (not shown).

The terminal block 13 has three holes 14u,
The three grooves 20v are formed in parallel with each other in the axial directions of 14v and 14w, and extend in the wiring direction as shown in FIG.
u, 20v, 20w, and a groove 20u,
It can be divided into a lid 13a that covers the open upper surface of 20v and 20w. Since the division surface is also formed on the annular cores 16u and 16w embedded around the connection terminals 15u and 15w at both ends of the base 13, the annular core 1
6u and 16w are the portions 16ub and 16wb embedded in the base 13b and the lid 1 as the terminal block 13 is divided.
It is divided into portions 16ua and 16wa embedded in 3a.

In the first embodiment described above, the connection terminals 15u and 15w are arranged on the inner periphery of the annular cores 16u and 16w, so that the terminal block with a built-in current sensor can be miniaturized, and the dividing surfaces 19a and 19b can be divided. From the terminal block 13 to the base 13b
Connection terminals 15u, 15
When a current path (not shown) is removed from the v, 15w, a mechanical closed circuit surrounding the connection terminals 15u, 15v, 15w is opened, and a portion covering the connection terminals 15u, 15v, 15w is removed, and a conventional circuit is removed. Wiring workability is maintained.

Hereinafter, the same portions will be described using the same reference numerals and names.

[Second Embodiment] Next, a second embodiment of the present invention will be described.
The embodiment will be described with reference to the drawings. FIG. 5 is a vertical sectional view of a terminal block with a built-in three-phase three-wire current sensor according to the present invention.

The lid 13a constituting the terminal block 13 has portions 16ub, 16w included in the base 13b as in FIG.
b and portions 16 of the annular core, each forming a magnetically closed circuit
ua and 16wa are embedded. The lid portion 13a is formed such that the embedded annular cores 16ua, 16wa are formed on the dividing surface 19a.
So that you can go in and out of the predetermined length from the vertical direction,
The moving allowance 24u, 2
4w. Also, the lid 13a has a lid 13a.
When is attached to the base 13b, springs 21u and 21w, which are urging means for applying a force in a direction of bringing the dividing surface 19a closer to the dividing surface 19b to the respective annular cores 16ua and 16wa on the lid 13a side, are embedded.

By providing the springs 21u and 21w,
Part 16ua of the annular core embedded in the lid 13a, 1
6wa and part 16 of core member embedded in base 13b
ub, 16wb, a force is applied in a direction perpendicular to the respective dividing surfaces 19a, 19b, and the annular cores 16ua, 16u
b, 16wa and 16wb, the joining of each is strengthened. This prevents leakage of magnetic flux from the divided surfaces 19a and 19b, and prevents a decrease in accuracy of current detection.

[Third Embodiment] Next, a third embodiment of the present invention will be described.
The embodiment will be described with reference to the drawings. In this description, the description of the same parts as those in FIGS. FIG. 6 is a longitudinal sectional view of a three-phase three-wire terminal block with a built-in current sensor according to the present invention.

As shown in FIG. 6, the table 13 has
Similarly, three holes 14 penetrating the inside in the wiring direction
u, 14v, and 14w have connection terminals 15u, 15
v, 15w are provided. In addition, the three holes 14
Annular cores 16u, 16v, and 16w are embedded in all of u, 14v, and 14w so as to be wound therearound. Notches 17u, 17v, 17 into which the Hall elements are inserted are respectively formed in the annular cores 16u, 16v, 16w.
w is provided. The cover 13a is provided in a space for embedding the annular core therein so that the embedded annular cores 16ua, 16va, 16wa can freely move in and out of the dividing surface 19a by a predetermined length in a vertical direction.
u, 24v, 24w. Further, the lid 13a
When the lid 13a is attached to the base 13b,
The force in the direction perpendicular to the dividing surface 19a in the direction of the dividing surface
annular cores 16ua, 16va, 16w embedded in a
a, springs 21u and 21 as urging means, respectively.
v and 21w are embedded. Furthermore, the base 13b has annular cores 16ub, 16vb, 1 on the dividing surface 19b.
Nonmagnetic and insulating magnetic shielding plates 22x and 22y projecting from the dividing surface 19b during 6 wb
Is embedded. The length of the magnetic shielding plates 22x and 22y in the wiring direction is larger than the length of the annular cores 16u, 16v and 16w in the wiring direction. Also, the lid 13a
Have magnetic shielding plates 22x, 22 provided on the main body 13b.
A concave portion (not shown) having a size surrounding a portion of y that protrudes from the cut surface 19b is provided.

By providing the magnetic shielding plates 22x and 22y, a plurality of adjacent connection terminals 15u, 15v and 15w are provided.
In the terminal block with a built-in current sensor, each of which has an annular core, adjacent annular cores 16u and 16v, 16v and 16v
Mixing of the leakage magnetic flux between w is cut off. Thereby, the leakage magnetic flux is induced in the annular core, and it is possible to prevent the accuracy of current detection from lowering.

[Other Embodiments] In the above embodiment, the Hall element was used to detect the magnitude of the magnetic field generated in the annular core. It is also possible to use a sensor for detecting the force, for example, a sensor coil or a magnetoresistive element.
Further, in the above-described embodiment, three terminals are used as the terminal block, but it is needless to say that one terminal or a plurality of terminals other than three can be applied. Further, the means for detecting the magnitude of the magnetic field in the annular core such as the Hall element is fixed to the terminal block, but may be detachable from the terminal block.

In the above embodiment, the terminal block is formed of plastic in order to realize an electrically insulating terminal block. However, the terminal block may be formed of another electric insulating material, for example, ceramics. May cover the surface of the terminal block formed of a conductive material, or any other material may be used as long as the terminal block is formed to have electrical insulation.

In the above embodiment, the annular core is made of directional silicon. However, it goes without saying that the annular core may be made of another ferromagnetic material such as ferrite. Further, although the magnetic shielding plate is formed of ceramics, it may be formed of a non-magnetic and electrically insulating material such as plastic or glass.

In the above embodiment, the terminal block is divided into upper and lower portions on the lid and the base. However, when the terminal block has a plurality of terminals, a plurality of terminals may be provided for each phase.
In the above embodiment, the upper surface of the connection terminal and the entire upper surface of the terminal block are divided, but at least the size of the connection terminal and a space where a jig used for wiring work can be operated are secured to cover the connection terminal. It is sufficient that the annular core can be removed.

In the above embodiment, a spring is used as the urging means. However, another elastic body such as rubber may be used.
The pressure of air, liquid, or the like may be applied. Also,
In the above embodiment, the biasing means is provided on the annular core on the lid side as the installation position. However, various positions may be considered depending on the location on the base side or how the terminal block is divided.

[0043]

As described above, in the terminal block with a built-in current sensor according to the present invention, since the ferromagnetic annular core for forming the current sensor is provided around the connection terminal, a conductive metal fitting is not required and the conventional one is used. The size can be reduced by the amount of the conductive metal fitting. In addition, since the portion of the annular core and the terminal block that cover the connection terminal is configured to be removable, the portion that covers the connection terminal is removed when the current path to the connection terminal is removed, so that the same wiring as in the past can be achieved. Workability is obtained. Further, the provision of the guiding means for guiding the leakage magnetic flux from the split surface into the annular core suppresses a decrease in the current detection capability due to the leakage magnetic flux.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a current sensor using a Hall element.

FIG. 2 is a diagram illustrating an example of a drive circuit for driving a Hall element.

FIG. 3 is a vertical sectional view of the terminal block with a built-in current sensor according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing the entirety of the terminal block with a built-in current sensor according to the first embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of a terminal block with a built-in current sensor according to a second embodiment of the present invention.

FIG. 6 is a longitudinal sectional view of a terminal block with a built-in current sensor according to a third embodiment of the present invention.

FIG. 7 is a diagram showing a configuration of a current sensor using a conventional Hall element. 2A is a plan view, FIG. 2B is a side view, and FIG.

[Explanation of symbols]

1 Current path 2 Annular core 5 ····· Hall element 13 ···· Terminal block 13a ····· Lid 13b ······· ······· Base 15,15u, 15v, 15w ··· Connection terminal 16,16u, 16v, 16w ··· Circular core 16ua, 16va, 16wa ··· A portion of the circular core embedded in the lid 16 ub, 16 vb, 16 wb: annular core portion embedded in base 18 u, 18 v, 18 w ... Hall element 19 a, 19 b ... dividing surface 21 u, 21 v, 21 w・ ・ ・ ・ ・ ・ Spring 22x, 22y ・ ・ ・ ・ ・ ・ ・ ・ ・ Magnetic shielding plate

Claims (5)

[Claims] 1. A connection terminal for connecting a current path, an electrically insulating terminal block provided with the connection terminal, and a strong terminal disposed on the terminal block surrounding the current path connected to the connection terminal. A current sensor built-in terminal block comprising a magnetic annular core, and capable of detecting a current flowing through the current path by detecting a magnitude of a magnetic field generated in the annular core; A terminal block with a built-in current sensor, wherein the connection terminal is disposed on the terminal block. 2. The terminal block with a built-in current sensor according to claim 1, wherein said terminal block is divided into a portion covering said connection terminal and a portion to which said connection terminal is attached, and said annular core is at least said ring core. A terminal block with a built-in current sensor, which is divided into a cover for covering the connection terminal and a base other than the cover. 3. The current sensor built-in terminal block according to claim 2, further comprising: a leakage magnetic flux guiding means for guiding a leakage magnetic flux from a division surface of said annular core into said annular core. Built-in terminal block. 4. The terminal block with a built-in current sensor according to claim 3, wherein said leakage magnetic flux guiding means sets a distance between a surface of said divided surface on a lid side and a surface of said divided surface on a base side. A current sensor built-in terminal block, which is a biasing means for applying a contracting force. 5. The terminal block with a built-in current sensor according to claim 3, wherein said leakage magnetic flux guiding means is a nonmagnetic and electrically insulating magnetic flux shielding means surrounding a periphery of said divided surface. Terminal block with built-in current sensor.