JPH1138109A - Magnetic sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic sensor which can be manufactured easily and the metallic terminal of which can be surely fixed to a magnetic sensor element. SOLUTION: A conductive paint layer 161 and an elastic conductive paint layer 163 are formed in the electrode pattern 155 section of a magnetic sensor element 15 having a magnetic reluctance pattern on the surface of a substrate 15 by printing. The magnetic sensor element 15 and a terminal 20 are insert- molded with a molding material 30 while one end of the terminal 20 is brought into contact with the surface of the elastic conductive paint layer 163.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic sensor.

[0002]

2. Description of the Related Art Conventionally, magnetic sensors for detecting the state of a magnetic field using a magnetic resistance have been developed and used for various electronic devices.

FIG. 8 is a view showing one example of use of a conventional magnetic sensor of this type. FIG. 8A is a plan view, and FIG. 8B is a sectional view taken along a line aa in FIG. is there.

In FIG. 1, reference numeral 100 denotes a surface-facing brushless DC motor, on which a rotatable rotor yoke 111 is mounted.

A magnet 113 for detecting the rotational speed of the rotor yoke 111 is provided on the outer peripheral side of the rotor yoke 111.
A magnetic sensor 117 for detecting the magnetism of the magnet 113 is mounted on the fixed yoke 101 near the outer peripheral side surface of the magnet 113.

The magnetic sensor 117 has a plate-shaped magnetic sensor element 117a mounted on a resin holder 117b and a solder 1 on the front surface of the magnetic sensor element 117a.
The four metal terminals 117c connected at 17d are pulled out to the back side of the holder 117b and connected to a circuit pattern (not shown) provided on the fixed yoke 101 by solder 119.

[0007]

However, the conventional magnetic sensor 117 has the following problems. In order to manufacture the magnetic sensor 117 having the above structure, there are three steps: a step of fixing the metal terminal 117c to the magnetic sensor element 117a, a step of molding the mold resin holder 117b, and a step of attaching the magnetic sensor element 117a to the holder 117b. This necessitates a process, which complicates the production, and hinders a reduction in the production cost, especially during mass production.

[0008] Metal terminal 1 to magnetic sensor element 117a
Although the fixing of 17c is performed by the solder 117d, the connection strength is not sufficient. Therefore, as shown in FIG. 8B, it is necessary to apply a reinforcing agent 117f on the solder 117d. This hindered cost reduction.

The present invention has been made in view of the above points, and an object of the present invention is to provide a magnetic sensor which is easy to manufacture and can securely fix a metal terminal to a magnetic sensor element.

[0010]

According to the present invention, there is provided a magnetic sensor element comprising a magnetoresistive pattern provided on a surface of a substrate and an electrode pattern drawn from the magnetoresistive pattern, and one end of which is provided with the magnetic sensor element. A metal plate terminal connected to the electrode pattern of the magnetic sensor element, and the magnetic sensor element and the terminal are insert-molded while exposing the magnetoresistive pattern forming surface and projecting the other end of the terminal to the outside. And a molded product comprising the magnetic sensor. According to the present invention, a conductive paint layer is formed on the surface of the electrode pattern of the magnetic sensor element. According to the present invention, an elastic conductive paint layer is interposed between the electrode pattern and the terminal. In the present invention, a hot-melt type conductive adhesive is interposed between the electrode pattern and the terminal.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view showing a magnetic sensor 10 according to an embodiment of the present invention, and FIG.
It is AA sectional drawing of.

As shown in FIGS. 1 and 2, the magnetic sensor 10 has one end of four metal terminals 20 connected to a lower portion (an electrode pattern 155 described below) of a flat magnetic sensor element 15 and directly connected to the periphery thereof. The molded product 30 is formed by molding. Hereinafter, each component will be described.

FIG. 3 is an enlarged perspective view showing the magnetic sensor element 15. As shown in FIG. As shown in FIG.
A desired magnetoresistive pattern 15 is formed on the surface of a substrate 151 made of flat glass, silicon or ceramic.
3 and four electrode patterns 155 drawn from the magnetoresistive pattern 153. Each electrode pattern 155 is provided near the lower side of the substrate 151. The magnetoresistive pattern 153 is formed by coating a protective film on a permalloy thin film, and the electrode pattern 155 is formed by forming a nickel layer or a copper layer as an uppermost layer by vapor deposition or electroless plating. ing.

Returning to FIGS. 1 and 2, the molded product 30 is molded in a substantially convex shape, and the magnetic sensor element 15 is provided at the center thereof.
Is formed with an element holding part 31 in which the surface on which the magnetoresistive pattern 153 is formed is exposed, and fixing parts 33 and 35 provided on both sides of the element holding part 31. The fixing portion 33 has a projection 34, and the fixing portion 35 has a through hole 36.

The magnetic sensor element 15 of the element holding section 31
The recess 32 is provided in three places around the. The other end of the metal terminal 20 whose one end is connected to the electrode pattern 155 (see FIG. 3) of the magnetic sensor element 15 in the molded product 30 protrudes outside from the molded product 30 and is bent rearward.

In this embodiment, as shown in FIG. 2, a conductive paint layer 161 is formed on the electrode pattern 155 (the thickness is not shown in the figure) of the magnetic sensor element 15, and an elastic conductive paint layer 163 is formed thereon. Are printed, and the metal terminals 20 are connected by being pressed onto the elastic conductive paint layer 163 without any adhesive.

Here, as the material of the conductive paint layer 161, for example, a material obtained by kneading silver powder with a phenolic thermosetting resin is used. The material of the conductive paint layer 161 may be any material as long as it can be printed on the electrode pattern 155.

As the material of the elastic conductive paint layer 163, a material obtained by kneading silver powder with a thermosetting crosslinked urethane resin is used. The elastic conductive paint layer 163 has a predetermined rubber elasticity even after printing and drying. The material of the elastic conductive paint layer 163 may be any material as long as it has a property of having rubber elasticity after drying.

Next, a method of manufacturing the magnetic sensor 10 will be described. That is, to manufacture the magnetic sensor 10, first, four metal terminals 20 (only one is shown in FIG. 4) are placed on the lower mold E as shown in FIG.

Then, a conductive paint layer 161 and an elastic conductive paint layer 163 are formed on the four electrode patterns 155 of the magnetic sensor element 15 in advance by printing and drying, respectively. Resistance pattern 1
It is placed on the lower mold E with the 53 forming surface facing down. At this time, the magnetic sensor element 15 has three guide projections E1 provided on the lower mold E (only two are shown in FIG.
Numeral 1 is positioned on the front side of the right guide projection E1 shown in FIG. 4 and provided at a position to guide the outer peripheral side of the magnetic sensor element 15 on the front side of the paper surface). That is, the three concave portions 32 shown in FIG. 1 are formed by providing three guide projections E1. At this time, the surfaces of the four elastic conductive paint layers 163 directly contact one end surfaces of the metal terminals 20.

When the magnetic sensor element 15 is placed on the lower mold E, the upper end b of the magnetic sensor element 15 is blown in the direction of arrow B shown in FIG. The magnetic sensor element 15 may be reliably positioned so that a gap is not formed between the magnetic sensor element 15 and the magnetic sensor element 15.

Next, the upper mold F is placed on the lower mold E to clamp the metal terminal 20. In this state, the injection pressure is, for example, about 260 ° C. from the pin gate F1 provided on the upper mold F side. A high-temperature and high-pressure molten mold resin of about 100 to 600 kgf / cm ² , for example, polybutylene terephthalate (PB
T), polyethylene terephthalate (PET), polyphenylene sulfide (PPS) or the like is press-fitted, and the cavities F3 and E3 provided in the upper and lower molds F and E are filled with a mold resin.

Each metal terminal 20 is pressed against the elastic conductive paint layer 163 by the injection pressure of the molten mold resin. As shown in FIG.
63 is slightly pressed in the thickness direction and is elastically deformed, so that the periphery thereof is filled with the mold resin (that is, the molded product 30). The elastic conductive paint layer 163 and the metal terminals 20
The contact surface is not bonded with any adhesive and is merely mechanically pressed (elastic contact), but the electrical connection is sufficient.

After the molten mold resin has solidified, the upper and lower molds F and E are removed, and then the metal terminal 20 is bent to the rear side of the molded product 30 as shown in FIGS. Complete.

In the above embodiment, the pin gate F1
Is the position shown in the figure, that is, a position near the lower portion of the magnetic sensor element 15 (in FIG. 4, a position near the right end of the magnetic sensor element 15).
The reason is that when the molten mold resin is injected from the pin gate F1, the molten mold resin
Is pushed upward (to the left in FIG. 4) so that the upper end portion b of the magnetic sensor element 15 is always in contact with the base a of the guide projection E1, so that the dies E and F of the magnetic sensor element 15 are surely formed. This is because the positioning in the inside can be performed. When the pin gate F1 is at this position, the above-described positioning means by air blowing or the like is not necessarily required. Conversely, when another positioning means by air blowing or the like is performed, the position of the pin gate F1 is set to another location. It is good, but it goes without saying that both are more effective.

In this embodiment, the elastic conductive paint layer 163 is provided between the electrode pattern 155 and the metal terminal 20.
The reason for intervening is as follows. That is, the molded product 30
Even if the mold resin expands and contracts around the pressure contact portion between the elastic conductive paint layer 163 and the metal terminal 20 by slightly expanding and contracting with the surrounding temperature change, the amount of expansion and contraction is The change in the amount of elastic deformation of the elastic conductive paint layer 163 is absorbed, and the metal terminal 20 and the elastic conductive paint layer 163 can always maintain an elastic contact state with an appropriate elastic contact force. Is no longer there.

The connection between the electrode pattern 155 and the metal terminal 20 is formed by a conductive paint layer 161 as shown in FIG.
May be omitted and only the elastic conductive paint layer 163 may be provided.
On the contrary, as shown in FIG. 7B, the elastic conductive paint layer 163 is formed.
May be omitted and only the conductive paint layer 161 may be used. Also in these cases, bonding with the metal terminal 20 by an adhesive is unnecessary.

When only the conductive paint layer 161 is used, rubber elasticity cannot be expected as in the case of the elastic conductive paint layer 163, but resin elasticity of the resin material constituting the conductive paint layer 161 can be expected.
In this case, after molding the molded article 30, the molded article 30
Metal terminal 2 utilizing the permanent shrinkage force when the material solidifies and cools
The connection with 0 is made firmly. If a material having a small amount of thermal expansion and contraction is selected as the material of the molded product 30, the connection state can be maintained well without any problem.

The conductive paint layer 161 and the elastic conductive paint layer 1
When the metal terminal 20 is directly connected to the copper layer or the nickel layer constituting the electrode pattern 155 shown in FIG. 3 by omitting both of the layers 63, the surface of the copper layer or the nickel layer is smooth and hard. Therefore, even if the metal terminal 20 is directly in contact with the metal terminal 20, the metal terminal 20 and the metal terminal 20 are brought into contact with no cushioning property at all, and the connection state is not good. On the other hand, as described above, if the conductive paint layer 161 and / or the elastic conductive paint layer 163 whose surface is not very smooth and which has a cushioning property as compared with the copper layer or the like are printed, the metal terminals 20 can be formed without an adhesive. Can be reliably maintained in a good condition.

The protrusion 3 provided on the molded product 30 shown in FIG.
Numeral 4 is for rotatably inserting the magnetic sensor 10 into a hole provided in a fixing member (fixed yoke 101 in FIG. 8) for fixing the magnetic sensor 10. A through hole 36 (not shown) is inserted into the through hole 36. (The screw 118 shown in FIG. 8A corresponds to this) for fixing the magnetic sensor 10 to the fixing member.

FIG. 9 is a side sectional view of a magnetic sensor 10-2 according to another embodiment of the present invention. This embodiment is different from the above embodiment only in that a hot melt type conductive adhesive layer 200 is used instead of the elastic conductive paint layer 163 shown in FIG. Since the manufacturing method is completely the same as the other components, the description thereof will be omitted.

FIG. 10 is an enlarged sectional view of a connection portion between the metal terminal 20 and the electrode pattern 155. In the case of the present embodiment, a thermosetting conductive paint layer 161 is printed and dried on the electrode pattern 155 in advance, and a hot-melt type conductive adhesive layer 200 is printed and dried thereon in advance, as in the above embodiment. . In this embodiment, as the conductive adhesive layer 200, a conductive resin mixed with a polyester resin and having a property of starting to soften at about 120 ° C. is used.

With the metal terminal 20 placed on the conductive adhesive layer 200, a molten molding resin to be a molded product 30 is injection-molded around the metal terminal 20 in the same manner as shown in FIG. Is pressed against the conductive adhesive layer 200, and at the same time, the conductive adhesive layer 200 is melted by the heat of the molten mold resin, so that the metal terminals 20 and the conductive paint layer 161 are formed.
Glue in between. The magnetic sensor 10-2 is completed when the molten mold resin cools and solidifies, but the conductive adhesive layer 200 also solidifies, so that the adhesion between the metal terminal 20 and the conductive paint layer 161 can be reliably performed.

In this embodiment, as shown in FIG. 11, the conductive paint layer 161 is omitted and the electrode pattern 15 is omitted.
The hot-melt type conductive adhesive 200 may be formed directly on 5.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to these embodiments, and various modifications such as those described below are possible. In order to prevent the magnetic sensor element 15 from separating from the molded product 30, as shown in FIG.
6 may be roughened (for example, the length from the peak to the valley of the unevenness is about 5 to 10 μm), or FIG.
(B) As shown in (b), the side surface 25 is tapered so as to expand toward the back side (for example, an inclination angle of 0.5 to 1.0 °).
You may leave it.

Needless to say, the shape and material of the magnetic sensor element 15, metal terminal 20, and molded product 30 can be variously modified.

[0037]

As described in detail above, the present invention has the following excellent effects. Since the electrical and mechanical connection between the magnetic sensor element and the terminal and the mechanical fixing by a molded product covering the periphery thereof can be performed in one step, the manufacturing can be performed easily and quickly, and the manufacturing cost during mass production can be reduced. Can be achieved.

Since the magnetic sensor element and the terminal are securely fixed by insert molding with the mold resin, the mechanical connection strength between the two is increased as compared with the case of fixing with solder or an ordinary adhesive.

When a conductive paint layer is formed on the surface of the electrode pattern of the magnetic sensor element, the connection with the metal terminal is ensured.

When an elastic conductive paint layer is interposed between the electrode pattern and the terminal, the connection with the metal terminal can be made more secure than by the elastic force.

When a hot-melt type conductive adhesive layer is interposed between the electrode pattern and the terminal, the connection with the metal terminal is more reliable than the case where the adhesive force is applied.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a magnetic sensor 10 according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a perspective view showing a magnetic sensor element 15;

FIG. 4 is an explanatory diagram of a method of manufacturing the magnetic sensor 10.

FIG. 5 is an enlarged sectional view of a connection portion between a metal terminal 20 and an electrode pattern 155.

FIGS. 6A and 6B are perspective views showing another magnetic sensor element.

FIGS. 7A and 7B are enlarged cross-sectional views of a connection portion showing another connection structure of the metal terminal 20 and the electrode pattern 155. FIGS.

FIG. 8 is a diagram showing one usage example of a conventional magnetic sensor;
FIG. 3A is a plan view, and FIG. 3B is aa of FIG.
It is sectional drawing.

FIG. 9 is a magnetic sensor 10 according to another embodiment of the present invention.
2 is a side sectional view of FIG.

FIG. 10 is an enlarged sectional view of a connection portion between a metal terminal 20 and an electrode pattern 155.

FIG. 11 is an enlarged sectional view of a connection part showing another connection structure of the metal terminal 20 and the electrode pattern 155.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Magnetic sensor 15 Magnetic sensor element 151 Substrate 153 Magnetic resistance pattern 155 Electrode pattern 161 Conductive paint layer 163 Elastic conductive paint layer 20 Metal terminal 30 Molded product 200 Hot melt type conductive adhesive layer

Claims (4)

[Claims] 1. A magnetic sensor element having a magnetoresistive pattern and an electrode pattern drawn from the magnetoresistive pattern provided on a surface of a substrate, and a metal plate terminal having one end connected to the electrode pattern of the magnetic sensor element. And a molded product obtained by insert-molding the magnetic sensor element and the terminal with the other end of the terminal protruding outside while exposing the magnetoresistive pattern forming surface. Magnetic sensor. 2. A conductive paint layer is formed on a surface of an electrode pattern of the magnetic sensor element.
A magnetic sensor as described. 3. The method according to claim 1, wherein an elastic conductive paint layer is interposed between the electrode pattern and the terminal.
A magnetic sensor as described. 4. The magnetic sensor according to claim 1, wherein a hot-melt type conductive adhesive layer is interposed between the electrode pattern and the terminal.