WO2003056347A1 - Current sensor - Google Patents

Abstract

A current sensor comprises a ring-shaped core so provided as to clamp a board with its own gap, a Hall device so provided on the board as to be arranged between core gaps, a U-shaped coil so provided as to cross a core magnetic path, and an electronic circuit section for amplifying the output of the Hall device. This constitution enables the coil to cross the core magnetic path by easily penetrating through coil ring holes even if the core gap is made narrower than the line diameter of the coil. Narrowing the gap between the core and the Hall device makes it easy to miniaturize the current sensor by an improvement in the performance of current sensing.

Description

 Specification Current detector

 The present invention relates to a current detector for detecting a current flowing in a device such as a motor. Background art

 A conventional current detector has a configuration as shown in FIGS. 11A and 11B, as disclosed in, for example, Japanese Patent Application Laid-Open No. 08-21105. FIG. 12A is a perspective view showing the configuration of a conventional current detector, and FIG. 12B is a side view thereof. A Hall element 22 is mounted on the substrate 21, and ring-shaped cores (hereinafter referred to as cores) 23 are formed on the upper and lower sides of the substrate 21 so as to sandwich the Hall element 22. A coil 24 is wound around the core 23 and a part of both ends thereof is fixed by soldering. The electronic circuit 25 comprises chip parts 25 A and I 2 C 5 B for amplifying the output of the Hall element 22, and outputs the current value detected through the terminal 26 as a voltage value. '

 Such a current detector is manufactured in the following manner. That is, first, on the substrate 21 are mounted the Hall elements 22 and the chip components 25 A, I 2 C 5 B, etc. constituting the electronic circuit 25. Next, the coil 24 prewound from the gap of the core 23 is inserted at a position crossing the magnetic path of the core 23. In this state, the core 23 is fixed so that the Hall element 2 2 is disposed in the gap portion of the core 23. Subsequently, the coil 24 is fixed to the substrate 21.

Also, such a current detector operates as follows. That is, the coil 24 is connected in series with a device such as a motor, and the current flowing in the device flows as it is. The current flowing through the coil 24 generates a magnetic flux in the core 23, and the generated magnetic flux changes the output voltage of the Hall element 22. Let The current detector detects the magnitude of the current flowing through the device by amplifying the change in the output of the Hall element 22 with the electronic circuit 25.

 However, in the above conventional configuration, in order to increase the output from the Hall element 22 in order to improve the performance as a current detector, it is necessary to increase the amount of magnetic flux of the core 23. For this purpose, it is necessary to narrow the gap between the cores or to increase the number of turns of the coil 24 wound around the core 23.

 However, in the conventional configuration, the coil 24 wound in advance is inserted from the gap of the core 2 3, and in this state, the Hall element 2 2 is fixed so as to be disposed in the gap. For this reason, it is impossible to make the gap of the core 2 3 smaller than the wire diameter (diameter) of the coil 2 4. Therefore, in order to improve the performance as a current detector, it is necessary to increase the number of turns of the coil 24 wound around the core 23. This makes miniaturization difficult. Disclosure of the invention

 The current detector according to the present invention comprises a ring-shaped core provided so as to sandwich a substrate between its gaps, a Hall element provided on the substrate so as to be disposed between the gaps of the core, and a core It has a U-shaped coil set to traverse the magnetic path, and an electronic circuit section for amplifying the output of the Hall element. Brief description of the drawings

 FIG. 1A is a perspective view showing a configuration of a current detector in a first embodiment of the present invention.

 FIG. 1B is a top view showing the configuration of the current detector in the first embodiment of the present invention.

 FIG. 1C is a side view showing the configuration of the current detector in the first embodiment of the present invention.

2A to 2C show the magnetism of the current detector according to the first embodiment of the present invention. It is a perspective view which shows the structure of a pneumatic circuit part.

 FIG. 3A is a side view showing the configuration of the current detector in the second embodiment of the present invention.

 FIG. 3B is a top view showing the configuration of the current detector in the second embodiment of the present invention.

 FIG. 3C is a perspective view showing the configuration of the current detector in the second embodiment of the present invention.

 FIG. 3D is a perspective view from the back of FIG. 3C.

 FIG. 3E is a diagram showing a configuration of a current detector in a second embodiment of the present invention.

 FIG. 4A is a side view showing the configuration of the current detector in the third embodiment of the present invention.

 FIG. 4B is a top view showing the configuration of the current detector in the third embodiment of the present invention.

 FIG. 4C is a perspective view showing the configuration of the current detector in the third embodiment of the present invention.

 FIG. 5A is a side view showing the configuration of the current detector in the fourth embodiment of the present invention.

 FIG. 5B is a top view showing the configuration of the current detector in the fourth embodiment of the present invention.

 FIG. 5C is a perspective view showing the configuration of the current detector in the fourth embodiment of the present invention.

 FIG. 6A is a side view showing the configuration of the current detector in the fifth embodiment of the present invention.

 FIG. 6B is a top view showing the configuration of the current detector in the fifth embodiment of the present invention.

 FIG. 7A is a side view showing the configuration of the current detector in the sixth embodiment of the present invention.

FIG. 7B is a perspective view showing the configuration of the current detector in the sixth embodiment of the present invention. FIG. 8A is a top view of a ring-shaped core of a current detector in a seventh embodiment of the present invention.

 FIGS. 8B and 8C are partially enlarged top views of the ring-shaped core for explaining the operation of the current detector in the seventh embodiment of the present invention.

 FIG. 9 is a top view showing the configuration of the current detector in the eighth embodiment of the present invention.

 FIG. 10A is a top view showing a configuration of a current detector in a ninth embodiment of the present invention.

 FIG. 10B is a side view of the ring-shaped core of the current detector in the ninth embodiment of the present invention.

 FIG. 10C is a view for explaining the force shimming portion of the ring core of the current detector in the ninth embodiment of the present invention.

 FIG. 10D is a diagram showing the configuration of a ring-shaped core of the current detector in the ninth embodiment of the present invention.

 FIG. 10E is a side view of another ring-shaped core of the current detector in the ninth embodiment of the present invention.

 Fig. 10 F is another side view of the ring core of Fig. 10 E.

 FIG. 11A is a perspective view showing the configuration of a conventional current detector.

 FIG. 11B is a top view showing the configuration of a conventional current detector. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the current detector in the embodiment of the present invention will be described with reference to the drawings. Note that components having similar configurations are described with the same reference numerals, and detailed description will be omitted.

(Embodiment 1)

 1A is a perspective view showing a schematic configuration of a current detector in Embodiment 1, FIG. 1B is a top view thereof, and FIG. 1C is a side view thereof.

In FIG. 1, a detection unit 6 integrated with resin is positioned and fixed on a substrate 1 by a soldering electrode unit 7. Detector 6 A ring-shaped core (hereinafter referred to as core) 3 having a gap, a Hall element 2 provided between the gaps, and a U-shaped coil 4 provided across the magnetic path of the core 3 are made of resin. It is integrated and configured. Further, on the substrate 1, there is provided an electronic circuit 5 composed of a chip component 5 A, an IC 5 B or the like for amplifying the output of the Hall element 2 in the detection unit 6 and detecting the current value. The electronic circuit 5 amplifies the output of the Hall element 2 to a desired voltage value and outputs it via the terminal 8.

 Such a current detector operates as follows. That is, the coil 4 is connected in series with a device such as a motor, and the current flowing in the device flows as it is. The current flowing through the coil 4 generates a magnetic flux in the core 3, and the generated magnetic flux changes the output voltage of the Hall element 2. By amplifying this change with the electronic circuit 5, the magnitude of the current flowing through the device is detected.

 Here, the wire diameter (diameter) of the U-shaped coil 4 is larger than the gap of the core 3 and smaller than the ring hole of the core 3. In addition, the gap of the core 3 is provided with a gap just so that the Hall element 2 can be disposed. Further, the U-shaped coil 4 is disposed so as to cross the magnetic path of the core 3 through one of the ring holes of the core 3 without inserting the gap from the gap as in the prior art.

 As a result, the gap between the core 3 and the Hall element 2 can be narrowed as narrowly as possible, so the amount of magnetic flux of the core 3 is increased. Therefore, as the number of turns of the coil wound around the core 3 is changed to the U-shaped coil 4, the reduced amount of magnetic flux is also covered. The output from Hall element 2 increases as a whole, and the performance as a current detector improves. In addition, since the coil 4 can be mounted very easily and efficiently, productivity is improved.

Next, the manufacturing process of the current detector with the above configuration will be briefly described. First, the core 3, the Hall element 2, and the coil 4 are disposed in the predetermined positional relationship as described above, and are integrally molded of resin to form the detection portion 6. Next, on the substrate 1, the detection unit 6 is a chip component that constitutes the electronic circuit 5. 5A, IC 5B, etc. Mount at the same position. Here, since the detection unit 6 is integrally formed of a resin, it can be mounted by an automatic mounting machine similarly to the chip parts 5A, IC 5B, etc. constituting the electronic circuit 5, and the productivity is greatly improved. improves.

 Next, the configuration regarding the mounting of the detection unit 6 on the substrate 1 will be described in detail. 2A to 2C are perspective views showing the configuration of the detection unit 6. FIG.

 In FIG. 2A, the detection unit 6 has a soldering electrode 7 and is positioned and fixed using this. Thereby, the detection unit 6 is easily positioned and fixed to the substrate in the same manner as the parts on the other substrates.

 Further, in FIG. 2B, the positioning projection 9 is provided on the bottom surface of the detection unit 6, and an engagement portion (not shown) to be engaged with the positioning projection 9 is provided on the substrate 1. Then, the detection portion 6 is easily positioned and fixed to the substrate 1 by engaging the positioning projection 9 with the engaging portion.

 The top surface of the detection unit 6 can be mounted by suction using an automatic mounting machine even when it is flat. Here, as shown in FIG. 2C, when the protrusion 10 for automatic mounting is provided on the upper surface of the detection unit 6, mounting with an automatic mounting machine becomes easier.

(Embodiment 2)

 3A is a side view showing a schematic configuration of the current detector in Embodiment 2, FIG. 3B is a top view, FIG. 3C is a perspective view, FIG. 3D is a perspective view from the back, FIG. Is a diagram showing a schematic configuration.

A Hall element 2 is disposed on the substrate 1 at a position straddling a notch 12 provided in the substrate 1. Further, the core 3 and the U-shaped coil (hereinafter, coil) 4 are disposed such that the hole element 2 is positioned in the gap portion of the ring-shaped core (hereinafter, core) 3. Further, the core 3 is configured to have a projecting portion 16 projecting toward the inside of the substrate notch portion 12 from the one end located on the side opposite to the substrate surface on which the hall element 2 is provided. The notch width of the substrate notch 12 is smaller than the width of the core of the portion where the core 3 faces the Hall element 2. This is easy The Hall element 2 can be attached so as to straddle the notch 12. The Povin 1 1 fixes a part of the coil 4. The electronic circuit 5 has the same configuration as that of the first embodiment, and outputs the detected current value to the external circuit through the terminal 8 as a voltage.

 This narrows the gap between the ring core and the Hall element 2. As a result, the magnetic flux generated by the current flowing through the coil 4 can be increased, and the performance as a current detector is improved.

 The width of the projecting portion 16 is smaller than the width of the portion where the core 3 faces the Hall element 2. As a result, even if the gap of core 3 is narrowed, the protruding portion 16 of core 3 is easily inserted into substrate 1 and Hall element 2 is attached to substrate 1, so that core 3 is positioned between the gaps of core 3. It can be installed as In addition, since the width of the portion close to the Hall element of the core 3 is reduced, the magnetic flux density in the portion where the width of the core 3 is small becomes high, and a high magnetic flux density can be applied to the Hall element.

 The povin 11 is preferably made of an insulating resin. This ensures insulation withstanding voltage between the coil and the other parts of the current detector. Further, the coil 4 is easily positioned and fixed to the substrate 1 and the core 3 by positioning and fixing the povin 11 on the substrate 1. In addition, it is preferable to apply insulating resin to the surface of the coil 4 and fix it on the substrate. As a result, the withstand voltage of the coil 4 and the other part than the coil of the current detector can be secured with a simple configuration.

Preferably, the surface of the povin 11 is covered with a conductive material (not shown), and the conductive material portion is connected to the ground of the electronic circuit 5 for amplifying the output of the Hall element 2. As a result, the conductive material covering the surface of Povin 11 becomes a shield. Further, it is preferable to cover the outermost layer of the core 3 with a conductive material (not shown) and connect this conductive material portion to the ground of the electronic circuit 5 for amplifying the output of the Hall element 2. By configuring in this manner, noise generated in the electronic circuit 5 when the potential of the coil 4 rapidly changes due to switching or the like in an apparatus using a current detector can be reduced. Method of covering with the above conductive material Examples of such a method include plating and a method of applying a conductive resin. Alternatively, a laminated core in which a layer made of a solderable material is laminated as the outermost layer may be used as the core 3 and connected to the ground of the substrate 1. This produces the same effect as described above.

 Further, as shown in FIGS. 3A to 3E, the povin 1 1 holding the coil 4 has a first flange 13, a second flange 14 and a holding part 15. As a result, when the core 3 and the coil 4 are assembled, the substrate 1 and the core 3 and the coil 4 are fixed by the first flange 13, the second flange 14 and the sandwiching part 15. By this, it is possible to position and fix the substrate 1 and the core 3 and the povin 1 1 with a simple configuration.

 Further, it is preferable to make the length of the terminal 8 connected to the external circuit longer than the lead terminal 4 A of the coil 4. Thus, when the current detector is attached to the mother substrate (not shown), the terminal 8 is first inserted into the hole of the mother substrate and positioned, and then the lead terminal 4A of the coil 4 is inserted. This makes it easy to mount the current detector on one substrate.

 Next, the manufacturing process of the current detector with the above configuration will be briefly described. First, the Hall element 2 and the components that make up the electronic circuit 5 are mounted on the substrate 1. Next, the coil 4 to which the povin 1 1 is attached in advance to the core 3 is inserted from the side of the core 3 and combined. Next, slide the core 3 and the coil 4 from the notches 12 and 12 A of the substrate 1 and attach them to the substrate 1.

 According to this configuration, the core 3 and the coil 4 can be easily assembled to the substrate 1 by being slid from the notched portion 12 of the substrate. In addition, since the coil 4 can be easily assembled to the core 3, these can be mounted very easily and efficiently, and the productivity is improved.

(Embodiment 3)

4A is a side view showing a schematic configuration of the current detector in Embodiment 3, FIG. 4B is a top view thereof, and FIG. 4C is a perspective view thereof. The basic configuration of the third embodiment is the same as that of the second embodiment. The difference from the second embodiment is that a protective resin 17 is provided so as to cover the Hall element 2, the gap of the core 3, and the substrate notch 12. This further improves the reliability, particularly the moisture resistance.

 The protective resin 12 is preferably made of a soft elastic resin. Thereby, the stress on the Hall element 2 in the use environment is relaxed, and the fluctuation of the output voltage value of the current detector generated by the stress on the Hall element 2 is reduced. (Embodiment 4)

 FIG. 5A is a side view showing a schematic configuration of the current detector in Embodiment 4, FIG. 5B is a top view thereof, and FIG. 5C is a perspective view thereof.

 The basic configuration of the fourth embodiment is the same as that of the second embodiment. A difference from the second embodiment is that a wall 18 is provided to cover the Hall element 2, the gap of the core 3, and the substrate notch 12. This configuration protects the internal configuration against the environment of use. Alternatively, a hollow cap may be provided instead of the wall 18.

(Embodiment 5)

 FIG. 6A is a side view showing a schematic configuration of the current detector in the sixth embodiment, and FIG. 6B is a top view thereof.

 In the figure, the Hall element 2 is disposed in the notch 12 provided in the substrate 1. Further, the core 3 and the U-shaped coil (hereinafter, coil) 4 are disposed such that the Hall element 2 is positioned in the gap portion of the ring-shaped core (hereinafter, core) 3.

As a result, the length of the gap between the core 3 which has conventionally been restricted by the thicknesses of the substrate 1 and the Hall element 2 is limited only by the thickness of the substrate 1, and the gap length of the core 3 can be narrowed. As a result, the current flowing through the coil 4 makes it possible to increase the magnetic flux generated in the core 3 and its gap, and the performance as a current detector is improved. In addition, when the configuration of the third embodiment is applied to the present embodiment, the protective resin can be easily applied from the upper surface of the notch portion 12 of the substrate, and the productivity is improved. Embodiment 6

 FIG. 7A is a side view showing a schematic configuration of the current detector in the sixth embodiment, and FIG. 7B is a perspective view of the same.

 The basic configuration of the sixth embodiment is the same as that of the second embodiment. A difference from the second embodiment is that a ground pattern 20 is formed on the surface of the substrate 1.

 Thus, the ground pattern 20 provided on the surface of the substrate between the U-shaped coil 4 and the electronic circuit 5 serves as a shield. As a result, noise generated in the electronic circuit 5 when the potential of the U-shaped coil 4 rapidly changes due to switching or the like in an apparatus using a current detector can be reduced. The configuration of the ground pattern 20 is, for example, composed of a whole surface or a grid pattern.

(Embodiment 7)

FIG. 8A is a side view of a ring core in a seventh embodiment, and FIG. 8B is a view for explaining the state of magnetic flux in the vicinity of the ring core in the seventh embodiment. In the present embodiment, one end of the ring core 3 on the side facing the Hall element 2 is arched in a direction away from the Hall element 2 to form a recess 3A. As a result, the position of the Hall element 2 is shifted with respect to the one end of the ring core 3 facing the Hall element 2 compared to the case where both ends of the ring core 3 are flat as shown in FIG. 8C. The rapid decrease of the magnetic flux generated in the gap portion of the ring core 3 can be improved at the end face portion of the one end portion of the ring core 3 opposite to the Hall element 2. (Embodiment 8) FIG. 9 is a top view of the current detector in the eighth embodiment. The basic configuration of the eighth embodiment is the same as that of the second embodiment. In the present embodiment, the inner peripheral surface 3 B and the outer peripheral surface 3 C of the corner portion of the ring-shaped core 3 are formed by curved surfaces. As a result, the magnetic flux generated in the gap portion of the ring core 3 increases. In the present embodiment, both the inner circumferential side 3 B and the outer circumferential side 3 C of the corner portion of the ring-shaped core 3 are formed as curved surfaces, but it is also effective to form either one as a curved surface.

(Embodiment 9)

 FIG. 10A is a top view of the current detector in the ninth embodiment. The basic configuration of the ninth embodiment is the same as that of the second embodiment. In the present embodiment, as shown in FIG. 10B, the ring-shaped core 3 is formed of the laminated core, and as shown in FIG. 1OA, the force shimming portion 3D is provided at the corner of each layer.

 As a result, the ring-shaped core 3 can be made of inexpensive silicon steel plate having high permeability. In addition, by providing the force shimming portion 3D at the corner of the laminated core, it can be handled as an integrated ring core, which facilitates assembly. The core material to be laminated may be other materials such as permalloy (nickel and iron alloy). Also, each layer of the laminated core may be constituted by one magnetic plate.

 Further, as shown in FIGS. 10D to 10F, the ring-shaped core 3 may be composed of two laminated cores.

 As a result, the gap of the ring core 3 is expanded and a coil (not shown) which is not affected by the wire diameter of the winding lead is inserted at a position crossing the magnetic path of the ring core 3 from the gap. Na becomes possible. In addition, by inserting and mounting the coil 4 wound in advance and narrowing the length of the gap, it is possible to increase the magnetic flux generated in the core 3 and its gap by the current flowing through the coil 4, and Performance is improved.

Also, since the length of the gap can be freely adjusted, the current flowing through the coil 4 adjusts the magnetic flux generated in the core 3 and its gap. As a result, it becomes possible to substitute the adjustment of the output voltage which has been performed in the amplification of the electronic circuit 5.

 At that time, one of the layers may be formed of a substantially L-shaped magnetic plate 3E, and each of the other layers may be formed of a substantially I-shaped magnetic plate 3F, which may be alternately stacked. . Thus, the ring-shaped core can be easily formed by lamination.

 Further, it is preferable to form a joint 3D, which is a pivot point of the two stacked bodies, by a V notch as shown in FIG. 10C. This makes it possible to easily form the joint, which is the pivot point of the two laminates, by punching the die. Industrial applicability

 According to the present invention, even if the gap of the ring-shaped core 3 is made smaller than the wire diameter of the U-shaped coil 4, it is possible to easily pass the coil 4 through the ring hole of the core 3 to cross the magnetic path of the core 3 Can. And by narrowing the gap between the core 3 and the Hall element 2, the performance of current detection is improved, and miniaturization is also difficult.

 In addition, by integrating the core 3, the Hall element 2 and the coil 4 with a resin, the moisture resistance of the device can be further improved. Also, in the opposite of the gap between the core 3 of the substrate 1. A substrate notch 12 is provided at a position corresponding to the position and at a position corresponding to the gap between the cores 3. Then, the Hall element 2 is disposed so as to straddle the substrate notch 12. With such a configuration, the core 3 and the coil 4 can be easily assembled to the substrate 1 by being slid from the notched portion 12 of the substrate 1.

Claims

The scope of the claims  1 and board,  A ring-shaped core provided to sandwich the substrate between the gaps;  A Hall element connected to the substrate so as to be disposed between the gaps;  A U-shaped coil provided across the magnetic path of the ring-shaped core;  Current detector. 2. The wire diameter of the U-shaped coil is larger than the gap of the ring core and thinner than the ring hole of the ring core,  The current detector according to claim 1. 3. At least the Hall element and the gap between the ring core are covered with resin,  The current detector according to claim 1. 4. At least the Hall element, and a wall surrounding the gap between the ring-shaped cores,  The entire substrate is coated with resin, except inside the wall,  The current detector according to claim 1. 5. At least the Hall element, and a hollow cap covering between the gaps of the ring core;  The entire substrate is coated with resin,  The current detector according to claim 1. 6. The ring-shaped core, the Hall element, and the U-shaped coil A detection unit in which 4 is integrated with resin;  The current detector according to claim 3. 7. The substrate has a structure in which a position corresponding to an opposite position between gaps of the ring core and a position corresponding to a gap between the ring core are cut out, and the Hall element is not Straddling the notch of the substrate,  The current detector according to claim 1. 8. A protrusion of the ring-shaped core, which protrudes toward the Hall element from one end located on the side opposite to the side of the substrate to which the Hall element is connected,  The current detection device according to claim 7. 9. The notch width of the substrate is smaller than the width of the core in the portion where the ring-shaped core faces the hole element.  The current detection device according to claim 7. The width of the protrusion is smaller than the width of the core of the portion of the ring-shaped core facing the Hall element.  The current detection device according to claim 8. 1 1. Further comprising a povin for fixing the coil,  The current detection device according to claim 7. An electronic circuit section provided on the substrate and for amplifying an output of the Hall element;  The surface of the povin is covered with a conductive material, and the conductive material is connected to the ground of the electronic circuit portion. A current detector according to claim 11. Five 1 3. Hall elements are disposed in the cutouts of the substrate,  The current detection device according to claim 7. 1 4. Having a ground pattern on the substrate surface,  The current detection device according to claim 1. 1 5. An electronic circuit section provided on the substrate for amplifying the output of the Hall element, further comprising:  The outermost of the ring core is covered with a conductive material, and the conductive material is connected to the ground of the electronic circuit part.  The current detection device according to claim 1. 1 6. The ring core is formed of a laminated core,  The current detection device according to claim 1.  1 7. A force shimming was provided at the corner of each layer of the laminated core  The current detection device according to claim 16. 8. Each layer of the laminated core consists of one magnetic plate,  The current detection device according to claim 17. 1 9. The ring-shaped core is composed of two members configured to be pivotable at a joint point,  The current detection device according to claim 1. 2 0. Each of the two members is composed of a laminate,  One of the layers is a substantially L-shaped magnetic plate, and the other is a layer of substantially I-shaped magnetic plates, each of which is alternately stacked. The current detection device according to claim 19. A joint serving as a pivot point of the two stacks is formed by a V notch,  A current detection device according to claim 20. An electronic circuit unit provided on the substrate and for amplifying an output of the Hall element;  The terminals of the electronic circuit section are longer than the lead terminals of the coil,  The current detection device according to claim 1. 2 3 One end of the ring-shaped core on the side facing the Hall element is bowed in the direction away from the Hall element,  The current detection device according to claim 1. 2 4. The povin has a first claw that secures the povin to the substrate,  The current detection device according to claim 1. 2 5. The povin has a sandwiching part for sandwiching the substrate,  The current detection device according to claim 1.  2 6. The povin has a second claw that secures the ring core to the povin,  The current detection device according to claim 1.