JPH0340352B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a magnetic sensor that generates a predetermined voltage in a coil in response to changes in the magnetic flux of a magnet, and particularly aims to provide a magnetic sensor whose quality is stable over a long period of time. be.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 9.

That is, in the figure, 1 is a case body made of synthetic resin with an open upper end as shown in detail in FIGS. 3 and 6 to 8, and has a keyhole shape consisting of a circular part and a rectangular part, It also constitutes a magnetic sensor case together with a cover plate 21, which will be described later. Reference numeral 2 denotes a keyhole-shaped bottom wall of the case body 1, and reference numeral 3 denotes a peripheral wall projecting integrally around the bottom wall 2 excluding the edges of the rectangular portion of the bottom wall 2 and a portion of the edges and both sides of the rectangular portion. , 4 are first protrusions integrally provided on both open ends of the peripheral wall 3 and the corresponding bottom wall 2 portions, and are connected to second locking portions 13 to be described later.
It also serves as a reinforcement for both open ends of the peripheral wall 3. Reference numeral 5 denotes a positioning circular protrusion concentric with the circular part of the case body 1, which is integrally protruded from the back surface of the bottom wall 2 of the case body 1, and when the magnetic sensor is placed on the base A. The magnetic sensor engages with the recess 1A to position the entire magnetic sensor.

6 is integrally provided on the inner surface of the bottom wall 2 of the case body 1 in a protruding manner. A hollow cylindrical convex wall concentric with the circular part of the case body 1 and the positioning protrusion 5. The circular part of the case body 1 has an annular coil storage part 7 and a magnet storage part 8 concentric with the coil storage part 7. It is divided into two parts. The outer diameter of the protruding wall 6 is smaller than the diameter of the positioning projection 5 by a predetermined value, and the height thereof is smaller than the height of the peripheral wall 3 by a predetermined value. Reference numeral 9 denotes an annular step formed around the tip of the convex wall 6, and an annular projection 23 of a cover plate 21, which will be described later, engages with the outer periphery of the annular step. Reference numeral 8 denotes a hollow cylindrical magnet housing concentric with the positioning protrusion 5, which is formed by the convex wall 6 and faces the positioning protrusion 5 via the bottom wall 2; By falling down to the positioning protrusion 5 side by a predetermined dimension,
Its height is higher than the height of the convex wall 6 by the amount of its depression. This is to accommodate a larger magnet 15 here.

Reference numeral 10 denotes a second protrusion in the form of a single piece that protrudes integrally from the bottom wall 2 so as to form a predetermined space between it and the circumferential wall 3 of the case body 1, and its height is a predetermined value greater than the height of the circumferential wall 3. It is formed small. Reference numeral 11 designates two parallel third protrusions integrally protruding from the bottom wall 2 portion located between the first protrusions 4, the height of which is smaller than the height of the peripheral wall 3 by a predetermined value. There is.
12 is a part of the peripheral wall 3, a part of the bottom wall 2, and a second
The two first locking portions are formed with both end surfaces of the projection 10 and into which the first projections 24 of the cover plate 21 (described later) fit, and serve to separate and lead out the signal lines 17 (described later). also. 13 is the first protrusion 4, the third
formed by the protrusion 11 and a part of the bottom wall 2,
The second protrusions 25 of the cover plate 21, which will be described later, fit into two second locking parts that bend and lock the end of the shield wire 18 into a U-shape, which will be described later. 14 is 2
A third locking portion formed by three third protrusions 11 into which a third protrusion 26 of a cover plate 21 (described later) is fitted, holds a signal line 17 and a shielded wire 18 (described later), and is externally connected to the third protrusion 11. It also has the role of deriving information. The case body 1 is configured as described above.

Reference numeral 15 denotes a cylindrical permanent magnet such as a ferrite magnet that is housed in the magnet housing 8 of the case body 1, and its outer diameter is the same as that of the convex wall so that a mold member 20, which will be described later, can enter between the convex wall 6 and the convex wall 6. 6, and its height is smaller than that of the magnet storage section 8.
The height is the same as that of Reference numeral 16 denotes an annular coil formed by winding an extremely thin conductive wire many times, which is housed in the coil storage portion 7 of the case body 1. The outer diameter and inner diameter of the coil 16 are the same as those of the mold member 20, which will be described later, on the convex wall 6. The dimensional relationship that allows penetration between the two and the peripheral wall 3 is taken into consideration. Further, its height is selected to be approximately the same as the height of the convex wall 6. Reference numeral 17 denotes two signal lines connected to the output ends of the coil 16, separated at the first locking part 10, led out to the outside through the third locking part 14, and connected to a control circuit (not shown). It serves to transmit the electromotive force generated in the coil 16 when the magnetic flux of the magnet 15 is disturbed. Further, this signal line 17 is connected in advance before the coil 16 is housed in the case body 1. Reference numeral 18 denotes a shielded wire whose end is bent into a U-shape and locked by the second locking part 13, and led out to the outside through the third locking part 14, and is connected to a conductive coating 29, which will be described later. electrically connected. Reference numeral 19 denotes a sheathing portion that covers the outer periphery of the signal line 17 and the shielded wire 18 so as to integrate them together, and 20 denotes the magnet 15, the coil 16, a part of the signal line 17, and the shielded wire inside the case body 1. After the end portions of the case body 1 are arranged as described above, the case body 1 is filled with a mold member such as epoxy resin and cured after a predetermined period of time.

Then, when this mold member 20 is hardened, the magnet 15 and the coil 1
6, and the connecting portion between the coil 16 and the signal line 17 are shielded from the outside air by the molded member 20 so as not to come into contact with the outside air.
6. In order to firmly hold the connection between the coil 16 and the signal line 17, the part of the signal line 17 located inside the case body 1, and the end of the shielded wire 18 in their respective predetermined positions, It is filled in each gap, each gap between each component and the case body 1, and the exposed portion of each component except for the end of the shield wire 18.

Reference numeral 21 designates a keyhole-shaped synthetic resin cover plate that is fitted into the upper opening of the case body 1 as shown in detail in FIGS. It is formed to be smaller than the circular portion of the case body 1 by a predetermined value so that a first peephole 22 is formed between it and the peripheral wall 3 when it is fitted into the upper open portion. Reference numeral 23 denotes an annular projection concentric with the circular portion of the cover plate 21, which is integrally provided on the back surface of the cover plate 21, and is an annular step portion 9 of the convex wall 6 of the case body 1.
Fits in. Reference numeral 24 denotes two first protrusions that are integrally provided on both sides of the rectangular portion of the cover plate 21, and are fitted into the first locking portions 12 of the case body 1, respectively, and also connect the signal line 17. It is held between the bottom wall 2. 25
are two second protrusions that are integrally provided at the corners of the rectangular portion of the cover plate 21, and are fitted into the second locking portions 13 of the case body 1, respectively, and are connected to the shield wire 18.
is held between the bottom wall 2 and the bottom wall 2. A third protrusion 26 is integrally provided between the second protrusions 25 and is fitted into the third locking part 14 of the case body 1.
A signal line 17 and a shield line 18 are sandwiched between the bottom wall 2 and the bottom wall 2. A second circular observation window 27 is formed at the center of the circular portion of the cover plate 21, and its diameter is smaller than the diameter of the magnet 15. 28 is a circular third observation window formed in the rectangular part of the cover plate 21 at approximately the center thereof as shown in the figure, and the two signal lines 1
7 are separated from each other at the first locking portion 12. The cover plate 21 is configured as described above. And this cover plate 21 is
After filling the mold member 20 as described above, before the mold member 20 hardens, the case body 1 is
The rectangular part of the cover plate 21 is attached to the rectangular part of the case body 1, the annular protrusion 23 is attached to the annular step part 9 of the convex wall 6 of the case body 1, and the first protrusion 2 is attached to the first locking part 12 of the case body 1.
4, the second protrusion 25 is fitted to the second locking part 13 of the case body 1, and the third protrusion 26 is fitted to the third locking part 14 of the case body 1, respectively. The mold member 20 is firmly fixed to the upper open portion of the case body 1 with adhesive properties. At this time, the outer surface of the cover plate 21 and the end surface of the peripheral wall 3 are flush with each other. The magnetic sensor main body is configured in this way. Reference numeral 29 denotes carbon and binder coated on the outer surface of the magnetic sensor body constructed as described above (the outer surface of the case body, the outer surface of the cover plate, the outer surface of the mold member present in the first to third observation windows). It is electrically connected to the extreme end of the shielded wire 18 with a conductive coating including the like.

The magnetic sensor according to the embodiment of the present invention is constructed as described above, and is manufactured as follows.

That is, the above-mentioned case body 1, the coil 16 to which the signal line 17 is connected, the permanent magnet 15, and the cover plate 21 are prepared in advance, and the coil 16 is placed in the coil storage part 7 in the case body 1, and the magnet storage Part 8
The permanent magnet 15 is housed in the housing, and the signal line 17 is guided out of the case body 1 through the first locking part 12 and the third locking part 14, and the shield wire 18
The ends of the two are bent into a U-shape and locked to the second locking part 13, respectively. At this time, the end of the shield wire 18 is extended to a portion of the case body 1 where the peripheral wall 3 does not exist.

Next, a mold member 20 made of epoxy resin or the like is placed inside the case body 1 housing the permanent magnet 15, coil 16, etc., and when the mold member 20 is hardened, the magnet 15, coil 16, coil 16, etc.
The connection part between the signal line 17 and the signal line 17 is the mold member 20.
to prevent contact with the outside air.
Moreover, the magnet 15, the coil 16, the connection between the coil 16 and the signal line 17, the portion of the signal line 17 located inside the case body 1, and the end of the shielded wire 18 are each firmly held in a predetermined position. , each gap between each part, each gap between each part and the case body 1,
The parts exposed to the outside air of each component except the end of the shielded wire 18 are filled.

Next, before this mold member 20 hardens, a cover plate 21 is attached, an annular protrusion 23 is attached to the annular step portion 9 of the convex wall 6 of the case body 1, and a first locking portion is attached to the first locking portion 12 of the case body 1. , a second protrusion 25 on the second locking part 13 of the case body 1, and a third protrusion 25 on the third locking part 14 of the case body 1.
By fitting the mold members 6 into each other, the mold member 20 is firmly fixed to the upper open portion of the case body 1 along with its adhesive properties. The magnetic sensor body is manufactured in this way. Note that at this time, the first to third locking portions 1
The signal wire 17 and the shield wire 18 located at 2, 13, and 14 are held between the bottom wall 2 of the case body 1 and the first to third protrusions 24, 25, and 26 of the cover plate 21, respectively.

Finally, after the mold member 20 has hardened, the magnetic sensor body is immersed in a liquid for forming a conductive coating, and the outer surface of the case body 1 and the cover plate 2 are
1 outer surface, and first to third peepholes 22, 2
By forming a conductive coating 29 on the outer surface of the mold member 20 existing at parts 7 and 28, and electrically connecting the conductive coating 29 to the outermost end of the shield wire 18 exposed to the outside during this immersion. Manufacture magnetic sensors.

As shown in FIGS. 1 and 2, the magnetic sensor described above is manufactured by fitting the positioning protrusion 5 into the recess 1A formed on the base A, and then attaching the positioning projection 5 to the base A.
The case body 1 is installed on the base A by sandwiching the rectangular part of the case body 1 between the protruding pillars 2A, and when the magnetic flux of the permanent magnet 15 is disturbed by the object to be detected, an electromotive force is generated in the coil 16. occurs.

Note that this electromotive force is introduced into a control circuit (not shown) through a signal line 17 and used to obtain desired data.

As explained above, the embodiments of the present invention have various effects as described below. That is, according to this embodiment, the magnet 15 and the coil 16 to which the signal line 17 is connected in advance are housed in the case body 1, and the coil 16, the magnet 15, and the coil 16 are also housed in the case body 1. The mold member 2 is installed so as to isolate the connection part with the signal line 17 from the outside air.
0, so the coil 16, magnet 15,
And the connection part between the coil 16 and the signal line 17 will not be oxidized and deteriorated, and the case body 1
and mold member 20 to form coil 16 and coil 1.
Since the connecting portion between the signal line 6 and the signal line 17 is protected from external impact, a strong magnetic sensor can be obtained.

Furthermore, since the mold member 20 is filled with parts such as the magnet 15 and the coil 16 so as to be fixed in the case body 1, the magnet 15 and the coil 16 can be fixed very easily. Moreover, even if this magnetic sensor is used in a place where it vibrates, the effects of the molded member 20 fixed to the case body 1 will cause misalignment between each component over a long period of time, resulting in changes in the characteristics of the magnetic sensor. This eliminates the inconvenience of having to do so.

In addition, since a conductive coating 29 is provided on each outer surface of the case body 1 that houses each component such as the magnet 15, the cover plate 21, etc., a shield wire is electrically connected to the conductive coating 29. 18, or shielded wire 18
In the case where the sensor is not provided with the sensor, it can be shielded through a conductive part provided on the base A etc. and electrically connected to the conductive coating 29, so that the sensor will not malfunction due to external noise. It disappears.

Further, according to this embodiment, especially the shield wire 18
Since it is provided on the sensor side, there is no need to provide a conductive part corresponding to a shielded wire on the base A side and make an electrical connection between this conductive part and the conductive coating 29, thereby reducing vibration etc. This eliminates the inconvenience of the contact being separated. In addition, the end of the shield wire 18 is connected to the second locking portion 13 of the case body 1.
Since the ends of the shield wires 18 are bent into a U-shape and secured at the mold member 20, the ends of the shield wires 18 can be secured well before filling the mold member 20, and the adhesiveness of the mold member 20 is improved after the mold member 20 is cured. At the same time, it can be firmly fixed. In addition, since the shield wire 18 is distributed to the left and right with respect to the lead-out part, the shield wire 18
Even when 8 is pulled from the outside, the force is applied evenly, making it difficult to break the wire. Also, connect the end of the shield wire 18 to the bottom wall 2 of the case body 1.
Since it is held between the shield wire 18 and the second protrusion 25 of the cover plate 21, the fixing becomes stronger, and when the mold member 20 is cured, the end of the shield wire 18 can be fixed well.

In addition, the case body 1 is formed into a keyhole shape, the coil 16 and magnet 15 are housed in the circular part, the signal line 17 etc. are led out from the rectangular part, and the positioning protrusion 5 is provided in the circular part. As shown in FIGS. 1 and 2, by simply providing a recess 1A and a pillar 2A in the base A, the sensor can be easily set to prevent rotation, and the overall shape of the sensor can be reduced. In addition, a magnet accommodating portion 8 smaller than the outer diameter of the positioning protrusion 5 is provided on the side facing the positioning protrusion 5, and the bottom surface of the magnet accommodating portion 8 extends toward the positioning protrusion 5, so that the overall shape of the sensor is The magnet 15 stored in the magnet storage section 8 can be made larger while remaining small.

In addition, a convex wall 6 is provided in the circular part of the keyhole-shaped case body 1, and the inside is divided into an annular coil storage part 7 and a magnet storage part 8 located in the center. Since the coil 16 and the magnet 15 are housed, and the cover plate 21 is provided on the open top of the case body 1, the coil 16 and the magnet 15 are
In addition to ensuring reliable positioning, flat surfaces can be provided on the upper and lower surfaces of the sensor, and the thickness of the sensor itself can be reduced.

Furthermore, since the above-mentioned cover plate 21 is provided with second and third peep windows 27 and 28, and the first peep window 22 is provided between the cover plate 21 and the case body 1, the sensor after completion of the sensor During the inspection, it is possible to check whether the coil 16 is housed in the first peephole 22 and whether the mold member 20 is well filled, and to check whether the magnet 15 is properly filled in the second peephole 27. It is possible to check whether the molded member 20 is covered with the outer surface of the magnet 15, and whether the two signal wires 17 are connected to the first one through the third viewing window 28. It is possible to check whether they are separated at the locking portions 12 and whether the mold members 20 are properly filled.

Here, the term "after the sensor is completed" refers to a state in which the mold member 20 is filled to hold the magnet, coil, etc. in the case body 1, and the cover plate 21 is fixed to the case body 1. In other words, this refers to the state before the conductive coating 29 is provided.

According to this embodiment, various effects as described above can be achieved.

In the above embodiment, the case where the conductive coating 29 is formed by immersing it in the liquid for forming the conductive coating has been described, but it is also possible to form the conductive plate into a container shape by press molding or the like and store the sensor in this. Needless to say, you can do as you like.

As described above, according to the present invention, a coil to which a magnet and a signal line are connected is housed in a case, and a mold for insulating the connection part between the coil and the signal line and the coil from the outside air is housed in the case. Since the material is filled, the connection between the coil and the signal line and the coil will not deteriorate due to oxidation, and the case and molded material can protect the connection and the coil from external shocks, making it very easy to use. Therefore, a highly reliable magnetic sensor can be obtained.

Furthermore, since there are second and third peepholes on the cover plate and a first peephole between the cover plate and the case, the first peephole can be used to inspect the sensor after it is completed. It is possible to check whether the coil is housed and whether the mold material is properly filled, etc. Also, the second observation window allows you to check whether the magnet is housed or not, and whether the outer surface of the magnet is also covered with the mold material. It is possible to check whether the two signal lines are separated from each other through the third observation window, and whether the mold material is properly filled. .

Furthermore, since the sensor is shielded by a shield member made of a conductive material, the sensor will not malfunction due to external noise.

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, in which Fig. 1 is a front view showing the entire magnetic sensor and the state in which it is attached to a base, Fig. 2 is a sectional view taken along the - line in Fig. 1,
Figures 3 and 4 are exploded perspective views of the magnetic sensor, Figure 5 is a front view of the magnetic sensor with the cover plate removed, Figure 6 is a front view of the case body of the magnetic sensor, and Figure 7 is a front view of the magnetic sensor case body.
The figures are a sectional view taken along the line -- in FIG. 6, FIG. 8 is a left side view of FIG. 6, and FIG. 9 is a bottom view of FIG. 6. In addition, the same reference numerals in the drawings indicate the same parts, and 1 is a case body, 15 is a magnet, 16 is a coil, and 20 is a molded member.

Claims (1)

[Scope of Claims] 1. A circular part that houses a magnet in the center and a circular coil concentrically with the magnet, and a part that separates and holds the signal line connected to the coil and leads it out to the outside. It has a keyhole shape consisting of a rectangular part provided with a bottom wall and a peripheral wall integrally projecting around the bottom wall except for the signal line lead-out part of the rectangular part of the bottom wall, and is open at the top. A case that has a keyhole shape equivalent to the keyhole shape of this case and is fitted into the upper opening part of the case, the outer diameter of the circular part is smaller than the outer diameter of the circular part of the case, When fitted into the case, a first peephole is formed between the case and the peripheral wall, a second peephole is formed in the center of the circular part, and a third peephole is formed approximately in the center of the rectangular part. The provided cover plate, the magnet, the coil, and the connection between the coil and the signal line housed in the case are isolated from the outside air and held in a predetermined position, and the cover plate is fixed integrally with the case. a mold member filled in order to
A magnetic sensor equipped with a shield made of conductive material that covers the viewing window.