JP3000094B2 - Manufacturing method of metal detection coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a metal detecting coil used in a metal detecting device for detecting metals contained in foods and drinks and various industrial materials.

[0002]

2. Description of the Related Art A conventionally known metal detecting device is provided with a transmitting coil for generating an alternating magnetic field, and a pair of receiving coils opposed to the transmitting coil and arranged to receive the alternating magnetic field. And configured to output a metal detection signal based on an unbalanced signal obtained by differentially detecting a change in an induced voltage generated in the pair of reception coils by a metal piece passing between the reception coil and the metal piece. I have.

[0003] Conventional transmission coils and reception coils are formed by winding a wire around the back of a substrate such as a bakelite to form a coil and fixing the coil with an adhesive, but the wire is flexible. However, since the winding operation of the electric wire is manually performed by an operator, it is inevitable that the winding method will vary.

Therefore, an electric wire is wound around a substrate and temporarily fixed,
In this state, the electric wire is slightly moved and adjusted, finally solidified with resin, and fixed to the coil and the substrate.

At this time, in order to secure a space through which the object passes as wide as possible, the substrate is made as thin as possible, and the seismic strength reduced by making the substrate thinner is reduced on the rear surface in a state where the substrate is incorporated in the apparatus. It was reinforced by pouring a large amount of resin. Therefore, it is necessary to form an opening for injecting the resin into the apparatus body.

As a method of forming a coil on a substrate without winding an electric wire, the present applicant has proposed to print and wire the coil on a printed circuit board (Japanese Patent Application No. 5-203548). reference).

[0007]

When a coil is printed and wired on a printed circuit board, the quality of the coil is stabilized and mass productivity is improved. However, since a high-frequency current flows through the coil, the conductor line of the printed circuit board is made wider and thicker. (A width of 1 mm or more and a thickness of 0.2 mm or more).

As described above, if the conductor lines of the printed circuit board are made wider and thicker, the performance can be maintained and the quality can be stabilized, but the price is inevitably increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the prior art, and does not require a large amount of resin to be injected, is stable in quality, and has a low cost, and a coil used in the metal detection device. Is to be realized.

[0010]

According to the present invention, there is provided a transporting means for transporting an object to be detected, a transmitting coil extending in a direction intersecting the transporting direction of the transporting means, and a detecting coil which is opposed to the transmitting coil. A coil is provided on each of the upstream side and the downstream side along the transport direction of the object, and a reception coil configured by the upstream coil and the downstream coil being respectively differentially coupled and arranged is provided. The coil is sandwiched between a first resin substrate and a second resin substrate having a plane parallel to the transport direction of the detected object, and the metal in the detected object is generated in the receiving coil. In the method for manufacturing a metal detection coil used in a metal detection device that detects a change in an induced voltage, a groove forming step of forming a wiring groove in a plane of the first resin substrate; A wiring process for wiring, Serial and is characterized in more becomes possible with attaching step of attaching the second resin substrate to wired surface of the first resin substrate.

[0011]

[0013]

The coil manufactured by the method of the present invention is sandwiched between the first resin substrate and the second resin substrate having a plane parallel to the direction in which the object is transported, so that no resin is injected. In both cases, the coil is firmly fixed to the substrate and the thickness of the substrate increases, so that the vibration resistance of the substrate itself improves.

When the electric wire is wired along the wiring groove recessed in the plane of the first resin substrate, the coil is formed uniformly.

[0015]

1 is a perspective view showing a metal detecting apparatus using a metal detecting coil manufactured by the method of the present invention, FIG. 2 is a front view including a cross section of a conveyor portion, and FIG. 3 is a longitudinal sectional view. 4 is a longitudinal sectional view in a direction orthogonal to FIG. 3, FIG. 5 is an exploded perspective view of the coil, and FIG. 6 is a rear perspective view of the coil.

In these figures, reference numeral 1 denotes a main body of a detection device, which includes an upper head 3 containing a receiving coil 2 (FIG. 3) and a lower head 5 containing a transmitting coil 4 (FIG. 3). The liners 6 are opposed to each other and fixed while maintaining a certain distance.

Note that the receiving coil 2 may be housed in the lower head 5 and the transmitting coil 4 may be housed in the upper head 3. A control box 8 on which an operation panel 7 is mounted is mounted on the upper head 3.

Among the control circuit boards, the high-frequency control circuit board 9
Are housed in the upper head 3 as shown in FIG. When the high-frequency control circuit board 9 is housed in the head as described above, it is not necessary to lead the high-frequency coaxial cable from the head.

A belt conveyor 11 is inserted through a detection path of the object 10 formed by the upper head 3, the lower head 5, and the liners 6, 6. 1
Reference numeral 2 denotes a driving roller of the belt conveyor 11, and reference numeral 13 denotes a driven roller. Reference numerals 14 and 15 are tension rollers. Reference numeral 16 denotes a support plate for the belt conveyor 11.

At the lower edge of the upper head 3 and the upper edge of the lower head 5, detection width indicating marks 17, 17, 17, 17 indicating the effective detection width of the object 10 are provided. Note that, as means for indicating the effective detection width of the detection target 10, a portion of the effective detection width may be colored in a different color from other portions instead of the detection width display mark.

The receiving coil 2 is made of a phenol resin (belite) on which paper is laminated and has a thickness of 10 mm.
The wiring is formed along a wiring groove 19 (FIG. 5) recessed in the plane of the first resin substrate 18 of FIG. The first
The dimensions of the resin substrate 18 are 230 mm wide and 4 mm long.
Although it is 00 mm, it is appropriately changed depending on the size and type of the detection object 10.

The width of the wiring groove 19 is formed to be equal to or slightly smaller than the wire diameter (2 mm) of the receiving coil 2.
Although the number of wiring grooves 19 at the center is two in the figure, two wires may be arranged in one wide wiring groove 19.

In this embodiment, the receiving coil 2 is formed by a single wire, but it is also possible to form a bundle of a plurality of wires. On the surface of the first resin substrate 18 where the receiving coil 2 is wired, the first resin substrate 18
2nd resin substrate 2 of the same material as above and having a thickness of about 5 mm
0 is stuck with an adhesive.

As described above, when the second resin substrate 20 on the side where the object 10 is located is formed to be thin, the passage of the object 10 (in the vertical direction in this embodiment) can be widened. it can. A shield layer 21 made of carbon paper is laminated on the second resin substrate 20.

A through hole 22 is formed in the first resin substrate 18 at one end of the receiving coil 2.
The leading end of the receiving coil 2 passes through the through hole 22 and is led out from the back surface of the first resin substrate 18 (FIG. 6). The two coils constituting the receiving coil 2 (the transported object 10
Upstream coil and downstream coil along the transport direction)
Are provided in the four corners of the first resin substrate 18 separately, and through-holes 23... Are formed through the through-holes 23.
1 is grounded (not shown).

The configuration of the transmitting coil 4 is the same as that of the receiving coil 2, and the only difference is the pattern of the coil. That is, the only difference is that the receiving coil 2 is configured by two loops, whereas the transmitting coil 4 is configured by one loop.

The resin substrates 18 and 20 may be a glass / epoxy laminate, or may be a single resin plate instead of a laminate.

Next, a method for manufacturing the receiving coil 2 will be described. First, after drilling predetermined through holes 22 and 23 in the first resin substrate 18, a wiring groove 19 is formed by NC milling or the like along the coil pattern shape. Next, the receiving coil 2 is wired along the wiring groove 19, and the lead-out portion is led out from the through-hole 22 to the back surface. Then, an adhesive is applied and the second resin substrate 20 is pressed and completed. I do.

In order to laminate the shield layer 21 on the second resinous substrate 20, one carbon paper is laminated instead of the ordinary paper in the course of laminating the second resinous substrate 20. do it.

When the second resin substrate 20 is pressed into contact with the first resin substrate 18 and heated, the degree of adhesion of the receiving coil 2 to the first resin substrate 18 is improved.
Further, the wiring groove 19 can be formed by a mold for molding the first resin substrate 18. The method for manufacturing the transmission coil 4 is the same as the method for manufacturing the reception coil 2.

[0031]

According to the present invention, the coil is sandwiched between the first resin substrate and the second resin substrate having a plane parallel to the direction in which the object is transported. Is firmly fixed.

Since the coil is wired along the wiring groove recessed in the plane of the first resin substrate, the coil can be manufactured uniformly, and the variation in the product is reduced. Further, since electric wires are used, the cost is lower than that of printed wiring. The first resin substrate is thicker than the second resin substrate, and when the second resin substrate is located on the passage side of the detection object, the passage of the detection object can be widened and the rigidity thereof can be reduced. Can be raised.

[0033]

A groove forming step of forming a wiring groove in the plane of the first resin substrate, a wiring step of wiring an electric wire in the wiring groove,
Since the method includes the step of attaching the second resin substrate to the wiring surface of the first resin substrate, a coil of uniform quality can be easily and quickly manufactured.

When the wiring groove is formed by a mold for molding the first resin substrate, a large number of coils can be manufactured with high efficiency. When the first resin substrate and the second resin substrate are bonded by applying pressure and heat, the degree of adhesion between the coil and the substrate is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a metal detection device of the present invention.

FIG. 2 is a front view including a cross section of a conveyor part of the metal detection device of the present invention.

FIG. 3 is a longitudinal sectional view of the metal detection device of the present invention.

FIG. 4 is a longitudinal sectional view of the metal detection device of the present invention in a direction orthogonal to FIG.

FIG. 5 is an exploded perspective view of the coil of the present invention.

FIG. 6 is a rear perspective view of the coil of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Detecting device main body 2 Receiving coil 3 Upper head 4 Transmitting coil 5 Lower head 6 Liner 7 Operation panel 8 Control box 9 High frequency control circuit board 10 Detected object 11 Belt conveyor 12 Drive roller 13 Follower roller 14 Tension roller 15 Tension roller 16 Support Plate 17 Detection width display mark 18 First resin substrate 19 Wiring groove 20 Second resin substrate 21 Shield layer 22 Through hole 23 Through hole

Claims (1)

(57) [Claims] 1. A transport means for transporting an object to be detected, a transmission coil extending in a direction intersecting the transport direction of the transport means, and a transmission coil opposed to the transmission coil and upstream along the transport direction of the object to be detected. side and downstream side respectively coil is provided, and the reception coil are provided constituted by an upstream side of the coil and the downstream side of the coil is s differentially coupling arrangement each, the
The coil has a plane parallel to the transport direction of the detected object
Sandwiched between the first resin substrate and the second resin substrate
It is, used in the metal detection device for detecting a change in the induced voltage generated metal of the object to be detected in the receiving coil
In the method for manufacturing the metal detection coil used ,
Groove formation for forming a wiring groove on a plane of the first resin substrate
A wiring step of wiring an electric wire in a wiring groove;
The second resin substrate on the surface of the resin substrate
Metal detection characterized by comprising an attaching step of attaching
Method of manufacturing coils for use.