JP6752511B2 - Electronic watt-hour meter - Google Patents

Description

The present invention relates to an electronic watt-hour meter configured by accommodating a conductor and an electronic circuit board in a housing , and particularly to an electronic watt-hour meter characterized by an electrical connection structure between the conductor and the electronic circuit board. It is related.

Conventionally, as this type of electrical connection structure, for example, there is a structure in which the terminal fitting 1 and the electronic circuit board 2 in the watt-hour meter shown in FIG. 1 are electrically connected. The terminal fittings 1 are arranged so as to be aligned with the terminal block portion 3a formed on the base 3 of the watt hour meter. The end of the lead wire 5 provided with the crimp terminal 4 is soldered to the electronic circuit board 2 by a flow method. The terminal fitting 1 and the electronic circuit board 2 are electrically connected by fastening the crimp terminal 4 to the terminal fitting 1 with a screw 6. Through this electrical connection, an operating voltage is input from the terminal fitting 1 to the electronic circuit board 2 via the lead wire 5, and an electrical signal is input / output.

Further, conventionally, as this kind of electrical connection structure, there is also a structure in which the conductor 7 and the electronic circuit board 2 in the watt-hour meter shown in FIG. 2 are electrically connected. The conductor 7 constitutes a current line and is mounted on the base 3 of the watt hour meter. A leaf spring 8 is attached to the electronic circuit board 2, and when the electronic circuit board 2 is attached to the base 3, the idle end of the leaf spring 8 comes into electrical contact with the conductor 7 mounted on the base 3. The leaf spring 8 is in electrical contact with a pad formed on the electronic circuit board 2, and the leaf spring 8 is in electrical contact with the conductor 7 to electrically connect the conductor 7 and the electronic circuit board 2. Will be done.

Further, conventionally, as this kind of electrical connection structure, there is also a structure in which a conductor and an electronic circuit board in a watt-hour meter disclosed in Patent Document 1 are electrically connected. In this structure, one end of a voltage line formed by bending an elongated plate-shaped conductor is fixed to an electronic circuit board by soldering. The other end of the voltage line is inserted into an opening formed at a bent portion of the rising portion of the conductor constituting the current line, and is sandwiched between the back surface of the terminal portion of the conductor and the upper surface of the terminal nut. When the terminal screw is screwed into the terminal nut and fixed in this state, the other end of the voltage line is firmly in electrical contact with the back surface of the terminal portion of the conductor, and the conductor and the electronic circuit board are electrically connected via the voltage line. Is connected.

Japanese Patent No. 3762883

However, in the electrical connection structure between the conventional terminal fitting 1 and the electronic circuit board 2 shown in FIG. 1, the cost of parts such as the lead wire 5 with the crimp terminal 4 and the screw 6 for fastening the crimp terminal 4 is required. At the same time, a wage or the like for forming a tap for screwing the screw 6 on the terminal fitting 1 is required. Further, it is necessary to solder the lead wire 5 to the electronic circuit board 2 by a flow method, and to tighten the screw 6 to the terminal fitting 1. Therefore, if the conventional electrical connection structure shown in FIG. 1 is used, the product cost of the electric device becomes high.

Further, when a voltage is applied to each electronic circuit board 2 at the same time in the assembled board state and a test is performed for the presence or absence of defects in the board, if the crimp terminal 4 is not fixed and idles, other electrons in the electronic circuit board 2 There is a possibility that the crimp terminal 4 may come into contact with a component or the like and cause a short circuit. Here, the electronic circuit board 2 is obtained by dividing a plurality of electronic circuit boards 2 into individual electronic circuit boards 2 by cutting a router or the like from an assembled board formed on one board. Therefore, it is necessary to fix the crimp terminal 4 on the substrate during the test, and it is necessary to release the crimp terminal 4 after the test is completed. For this reason, the work of attaching and detaching the crimp terminal 4 is required separately from the substrate test, which is troublesome during the substrate test.

Further, in the conventional electrical connection structure between the conductor 7 using the leaf spring 8 and the electronic circuit board 2 shown in FIG. 2, the cost and labor of parts can be reduced, but the parts of the leaf spring 8 can be transported and the electric power can be reduced. When assembling the watt-hour meter, the leaf spring 8 is easily deformed by applying an unintended force to the leaf spring 8. Further, a special mold is required for manufacturing the leaf spring 8, and in this respect, the component cost of the leaf spring 8 becomes high.

Further, also in the electrical connection structure between the conductor and the electronic circuit board disclosed in Patent Document 1, the voltage line formed by bending the elongated plate-shaped conductor is similarly easily deformed, and is shown in FIG. Problems similar to those of the conventional electrical connection structure occur.

The present invention has been made to solve such a problem.
In an electronic watt-hour meter configured by accommodating a current line connecting between a power supply terminal and a load terminal of each phase and an electronic circuit board in a housing composed of a cover and a base .
A shaft-like body having a plurality integrally formed with the base and extending between the current line and the electronic circuit board,
A pair of support columns formed protruding from the base located on both sides of the arrangement of each axial body,
A pad having one end formed on an electronic circuit board along the shaft, and a plurality of conductive coil springs having electrical contact with a current line at the other end at a contact pressure according to an extension force are provided.
The pads are formed side by side at a plurality of locations sandwiched between a pair of support columns on the back surface of the electronic circuit board to which each coil spring abuts, and the respective sizes of the coil springs are located at positions where the centers coincide with the center of the shaft. The dimension from the outer diameter of the pad to the end of the pad is set to be larger than the play dimension between the coil spring and the shaft .
Electronic circuit board is formed to protrude on side located on opposite sides of the arrangement of the pads, characterized by Rukoto includes a pair of projections to be fitted to the pair of support pillars.

According to this configuration, the current line and the electronic circuit board are assembled to the housing of the electronic watt-hour meter along the coil spring along the shaft, so that the current line and the electronic circuit board are electrically connected via the coil spring. Connected to. Therefore, the electrical connection between the current line and the electronic circuit board, along with component costs of shaft-like body and the coil spring, the effort and coil spring extending the axial body between the current line and the electronic circuit board to the shaft-like body It only takes a lot of man-hours. Therefore, the product cost of the electronic watt-hour meter can be reduced as compared with the case of using a conventional electrical connection structure using a lead wire provided with a crimp terminal. In addition, since floating crimp terminals are not used, when testing an electronic circuit board in the state of an assembled board, it is no longer necessary to perform the crimp terminal attachment / detachment work separately from the board test as in the past, and during the board test. Effort is reduced.

According to the electronic watt-hour meter of the present invention, it is possible to reduce the product cost of the electronic watt-hour meter . In addition, the labor required when testing the electronic circuit board in the state of the assembled board is reduced.

It is a top view which shows the 1st conventional electric connection structure. It is a perspective view which shows the 2nd conventional electric connection structure. (A) is a perspective view of an electronic watt-hour meter using the electrical connection structure according to the embodiment of the present invention with the cover removed, and (b) is an electronic circuit from the state shown in (a). It is a perspective view of the state which the substrate is removed. It is a perspective view which shows each part in the state shown in FIG. 3B by disassembling. (A) is a plan view of the electronic circuit board shown in FIG. 3 (a), and (b) is a diagram for explaining the dimensions between the pad, the coil spring, and the boss formed on the back surface of the electronic circuit board. It is a perspective view for demonstrating the electrical connection structure by the modification of one Embodiment.

Next, a mode for carrying out the present invention will be described in which the electrical connection structure between the conductor and the electronic circuit board in the electric device according to the present invention is applied to an electronic watt-hour meter.

FIG. 3A is a perspective view of an electronic watt-hour meter in a state in which an electrical connection structure between a conductor 11 and an electronic circuit board 12 is used according to an embodiment of the present invention. FIG. 3B is a perspective view of a state in which the electronic circuit board 12 is removed from the state shown in FIG. 3A.

An electronic watt-hour meter, which is a type of electric device, is configured by accommodating a conductor 11 and an electronic circuit board 12 in a housing composed of a cover (not shown) and a base 13. The conductor 11 is a current line connecting the power supply terminal and the load terminal of each phase, and a CT 14 for detecting an energizing current is passed through the left and right conductors 11. Further, the electronic component 15 is mounted on the electronic circuit board 12. In the electronic circuit board 12, the protrusions 12a formed so as to project in the horizontal direction are fitted to the support columns 13a formed so as to project from the base 13, so that the electronic circuit board 12 and the conductors 11 are fitted to each other as shown in FIG. 3A. It is supported by the base 13 while keeping a certain distance. A coil spring 16 which is an elastic body having conductivity is provided between each conductor 11 and the electronic circuit board 12.

As shown in FIG. 4, a boss 13b is erected on the base 13 of the portion on which the conductor 11 is placed. FIG. 4 is a perspective view showing each component in the state shown in FIG. 3 (b) in an exploded manner. The boss 13b is integrally molded with the base 13 by the resin forming the base 13. Further, each conductor 11 is formed with a hole 11a having a size through which the boss 13b penetrates. Each boss 13b constitutes a shaft-like body, penetrates the hole 11a, and extends between the conductor 11 and the electronic circuit board 12. Each conductor 11 is fixed to the base 11 by passing the boss 13b through the hole 11a. The boss 13b can be used as a positioning member for fixing or temporarily fixing the conductor 11. Each coil spring 16 is inserted into the boss 13b so as to be along the boss 13b, and is provided between each conductor 11 and the electronic circuit board 12.

FIG. 5A is a plan view of the electronic circuit board 12. Pads 17 are formed at three locations on the back surface of the electronic circuit board 12 with which the coil springs 16 come into contact. Each coil spring 16 is provided as described above, so that one end of the coil spring 16 comes into electrical contact with the pad 17 formed on the electronic circuit board 12, and the other end of the coil spring 16 comes into electrical contact with the conductor 11 at a contact pressure according to an extension force.

Regarding the size of each pad 17, the dimension A from the outer diameter of the coil spring 16 to the end of the pad 17 shown in FIG. 5B is larger than the backlash dimension B between the coil spring 16 and the boss 13b (A> B). Is set to be. With this dimensional setting, the entire end surface of the coil spring 16 is surely in contact with the pad 17.

According to the electrical connection structure between the conductor 11 and the electronic circuit board 12 according to the present embodiment, the conductor 11 and the electronic circuit board 12 are composed of a cover and a base 13 (not shown) along the coil spring 16 along the boss 13b. By assembling to the housing, the conductor 11 and the electronic circuit board 12 are electrically connected via the coil spring 16. Therefore, the electrical connection between the conductor 11 and the electronic circuit board 12 requires only the component cost of the coil spring 16 and the man-hours required to insert the coil spring 16 into the boss 13b. Therefore, the product cost of the electronic watt-hour meter can be reduced as compared with the case of using the conventional electrical connection structure shown in FIG. 1 in which the lead wire 5 provided with the crimp terminal 4 is used. Further, since the floating crimp terminal 4 is not used, when the electronic circuit board 12 is tested in the assembled substrate state, it is not necessary to perform the crimp terminal 4 attachment / detachment work separately from the substrate test as in the conventional case, and the substrate is not used. The time and effort during the test is reduced.

Further, since the step of aligning the coil spring 16 along the boss 13b is a work of simply inserting the coil spring 16 into the boss 13b, it is easy to develop it into automatic assembly using a robot. Further, by using the boss 13b as a guide for the coil spring 16, the coil spring 16 can be reliably brought into contact with the pad 17 of the electronic circuit board 12. Further, some bending of the coil spring 16 can be corrected by the boss 13b.

Further, in the electrical connection structure between the conductor 11 and the electronic circuit board 12 according to the present embodiment, the elastic body is configured as the coil spring 16. According to such a configuration, the leaf spring 8 in the conventional electrical connection structure shown in FIG. 2 and the elongated plate-shaped conductor in the conventional electrical connection structure shown in Patent Document 1 are formed by bending. Compared with the case of using a voltage line, it is possible to significantly prevent the elastic body from being deformed. Therefore, the elastic body according to the present embodiment is less likely to be deformed even when an unintended force is applied, and the packaging form of the parts at the time of transporting the parts can be simplified. In addition, the elastic parts can be easily handled when assembling the electronic watt-hour meter. In addition, a special mold for manufacturing the elastic body becomes unnecessary, and in this respect, the cost of manufacturing equipment for the elastic body can be reduced. Further, the coil spring 16 is less likely to settle than the leaf spring 8 and can have a large deflection. Therefore, the contact pressure between the pad 17 and the conductor 11 formed on the electronic circuit board 12 can be increased.

In the above embodiment, the shaft-shaped body is erected as a boss 13b on the portion where the conductor 11 is placed as a part of the base 13, so that the component cost of the shaft-shaped body and the shaft-shaped body are conducted. The man-hours extending between the 11 and the electronic circuit board 12 have been reduced, and the product cost of the electronic watt-hour meter has been greatly reduced. However, as shown in the perspective view of FIG. 6, the shaft-shaped body may be configured to stand on the conductor 11 as a shaft 18 whose one end is fixed to the conductor 11 by caulking or the like. In this case, the shaft 18 extends between the conductor 11 and the electronic circuit board 12 in the same manner as the boss 13b. In this configuration, the component cost of the shaft 18 and the man-hours such as caulking for extending the shaft 18 between the conductor 11 and the electronic circuit board 12 increase, but the lead wire 5 provided with the crimp terminal 4 is used. Compared with the case of using the conventional electric connection structure shown in the above, it is possible to reduce the product cost of the electronic watt-hour meter.

In the above embodiment, the electrical connection structure according to the present invention is applied to an electronic watt-hour meter, and the electrical connection according to the present invention is used for voltage input to the electronic circuit board 12 and input / output of an electric signal in the watt-hour meter. The case where the structure is used has been described. However, the electrical connection structure according to the present invention is not limited to application to a watt-hour meter, and includes other power distribution devices such as a time switch having a structure in which a conductor and an electronic circuit board are housed in a housing. It can be applied to general electric devices in the same manner, and similar effects can be obtained.

11 ... Conductor 12 ... Electronic circuit board 12a ... Protrusion 13 ... Base (housing)
13a ... Support pillar 13b ... Boss (axial body)
14 ... CT
15 ... Electronic components 16 ... Coil spring (elastic body)
17 ... Pad 18 ... Shaft (axial body)

Claims (1)

In an electronic watt-hour meter configured by accommodating a current line connecting between a power supply terminal and a load terminal of each phase and an electronic circuit board in a housing composed of a cover and a base .
A shaft-like body having a plurality integrally formed with the base and extending between said current line and the electronic circuit board,
A pair of support columns formed so as to project from the base located on both sides of the arrangement of the axial bodies,
A plurality of conductive coil springs having electrical contact with a pad formed on the electronic circuit board at one end along the shaft and with a contact pressure corresponding to an extension force at the other end. With
The pads are formed side by side at a plurality of locations sandwiched between the pair of support columns on the back surface of the electronic circuit board with which the coil springs abut, and the sizes of the pads coincide with the center of the shaft. The dimension from the outer diameter of the coil spring located at the position to the end of the pad is set to be larger than the play size of the coil spring and the shaft-shaped body .
The electronic circuit board is formed to protrude on side located on opposite sides of the arrangement of each of said pads, an electronic watt-hour meter, wherein the Ru with a pair of projections to be fitted to the pair of the support pillars.

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