JPH0330864Y2 - - Google Patents

Description

[Detailed description of the invention] This 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 that does not malfunction due to external noise. It is something.

An embodiment of this 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. Reference numeral 6 denotes a hollow cylindrical convex wall concentric with the circular part of the case body 1 and the positioning protrusion 5, which is integrally protruded from the inner surface of the bottom wall 2 of the case body 1. It is divided into a coil storage section 7 and a magnet storage section 8 concentric with the coil storage section 7.

Moreover, the outer diameter of this convex wall 6 is the same as that of the positioning protrusion 5.
It is formed to be smaller than the diameter of the peripheral wall 3 by a predetermined value, and its height 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, which is similar to the annular projection 2 of the cover plate 21, which will be described later.
3 engages its outer periphery. Reference numeral 8 denotes a hollow cylindrical magnet housing concentric with the positioning protrusion 5 which faces the positioning protrusion 5 via the bottom wall 2 and is formed by the convex wall 6, and the two sides of the bottom wall on which the convex wall 6 is formed. 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 convex protrusion that is integrally provided on the bottom wall 2 so as to form a predetermined space between it and the peripheral wall 3 of the case body 1, and its height is a predetermined value greater than the height of the peripheral wall 3. It is formed small. Reference numeral 11 denotes two parallel third portions integrally protruding from the bottom wall 2 portion located between the first protrusions 4.
The height of the protrusion is smaller than the height of the peripheral wall 3 by a predetermined value. Further, 12 is formed by a part of the peripheral wall 3, a part of the bottom wall 2, and both end surfaces of the second projection 10, and is connected to the first projection 2 of the cover plate 21, which will be described later.
The two first locking portions into which the first locking portions 4 are fitted also serve to separate and lead out signal lines 17, which will be described later.
Reference numeral 13 denotes a shield wire 1, which will be described later, formed by the first protrusion 4, the third 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 the two second locking parts, which are formed by bending the ends of the cover plate 8 into a U-shape and locking them. 14 is a third protrusion 26 of the cover plate 21, which will be described later, and is formed by two third protrusions 11.
This is the third locking part that fits into the signal line 17, which will be described later.
It also serves to hold the shield wire 18 and lead it out to the outside. As shown above, case body 1
is configured.

Reference numeral 15 denotes a cylindrical permanent magnet such as a ferrite magnet that is housed in the magnet storage section 8 of the case body 1, and the outside diameter of the convex wall is large enough to allow a mold member 20 (described later) to enter between the convex wall 6 and the convex wall 6. 6, and its height is formed to be the same as the height of the magnet housing section 8. Reference numeral 16 denotes an annular coil formed by winding an extremely thin conductive wire many times, which is housed in the coil storage part 7 of the case body 1. The outer diameter and inner diameter of the coil 16 are the same as that between the mold member 20 described later and the convex wall 6. The dimensional relationship that allows infiltration is taken into consideration between the spacer and the peripheral wall 3. Further, its height is selected to be approximately the same as the height of the convex wall 6. 17 are two signal lines connected to the output ends of the coil 16, separated at the first locking part 12, and guided to the outside through the third locking part 14,
It serves to transmit the electromotive force generated in the coil 16 due to disturbance of the magnetic flux of the magnet 18 to a control circuit (not shown). Also, this signal line 17 is connected to the coil 16
are connected in advance before being 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. 19 is signal line 1
7 and the shielded wire 18 are coated on their outer peripheries so as to integrate them together, and 20 is a sheathed portion that covers the magnet 15, the coil 16, a part of the signal wire 17, and the end of the shielded wire 18 in the case body 1. After arranging the case body 1 as described above, a mold member such as epoxy resin is filled into the case body 1 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 that they do not come into contact with the outside air, and the magnet 15 and the coil 1
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. A third circular viewing window 28 is formed in the rectangular portion of the cover plate 21, and is used to confirm whether the two signal lines 17 are separated from each other at the first locking portion 12. The cover plate 21 is configured as described above. This cover plate 21 is attached to the mold member 2 as described above.
0, and before the mold member 20 hardens, the rectangular part of the cover plate 21 is attached to the rectangular part of the case body 1, and the annular protrusion 23 is attached to the annular step part 9 of the convex wall 6 of the case body 1. Further, a first protrusion 24 is attached to the first locking part 12 of the case body 1, a second protrusion 25 is attached to the second locking part 13 of the case body 1, and a second protrusion 25 is attached to the third locking part 13 of the case body 1. A third protrusion 26 is provided on the stop portion 14.
By fitting them together, the mold member 20 is firmly fixed to the upper open portion of the case body 1 along with its 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 indicates the outer surface of the magnetic sensor body configured as described above (the outer surface of the case body, the outer surface of the cover plate,
A conductive coating containing carbon, a binder, etc. is coated on the outer surface of the mold member present in the first to third viewing windows, and is electrically connected to the extreme end of the shield wire 18.

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

That is, the case body 1 and the signal line 17 described above in advance
A coil 16, a permanent magnet 15, and a cover plate 21 are prepared, and the coil 16 is stored in the coil storage section 7 in the case body 1, and the permanent magnet 15 is stored in the magnet storage section 8. 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 1
8 are bent and locked into the second locking portion 13 into a U-shape, respectively.

At this time, the outermost 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 connecting portion 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. In this way, the magnetic sensor body is manufactured.

Note that at this time, the first to third locking portions 12,1
Signal line 17 and shield line 1 located at 3 and 14
8 is the bottom wall 2 of the case body 1 and the cover plate 21.
They are held by third protrusions 24, 25, and 26, respectively.

Finally, after the mold member 20 has hardened, the magnetic sensor main body is immersed in a conductive coating forming liquid, and the outer surface of the case main body 1, the outer surface of the cover plate 21, and the first to third Peep window 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 constructed by fitting the positioning protrusion 5 into the recess 1A formed in the base A, and by fitting the positioning protrusion 5 into the recess 1A formed in the base A. It is installed on the base A by inserting the rectangular part of the case body 1 between the two A, and an electromotive force is generated in the coil 16 when the magnetic flux of the permanent magnet 15 is disturbed by the object to be detected.

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 present invention constitutes a magnetic sensor using a case consisting of a keyhole-shaped case body and a cover plate, which are provided with a magnet storage part, a coil storage part, and a signal line lead-out part, and have a combination structure. As a result,
Since the storage part for magnets and the like and the lead-out part for the signal lines are on the same plane, the shape is thin and the signal lines can be led out from the lead-out part in an orderly manner while being protected. To assemble, insert the permanent magnet into the magnet housing inside the convex wall of the case body, store the ring-shaped coil with the signal wire connected in the coil housing, pull out the signal wire from the lead-out part, and then cover with the cover plate. Good quality and extremely easy to assemble. In this case, the permanent magnet and the annular coil are housed separately in a concentric magnet housing part and a coil housing part, separated by a convex wall, so there is no risk of contact or eccentricity due to movement even if an external force is applied. , there is no possibility of coil breakage or sensitivity reduction. In particular, according to the present invention, a shielded conductor wire in which a signal line is shielded with a shielded wire is used, and locking portions are provided on both sides to lock the shielded wires separately in an inverted U shape at the lead-out portion. The structure is such that the shielded wire is secured by the following. Therefore, the shielded conductor wires are automatically locked from both sides at the same time as they are assembled, so they do not move even if a somewhat strong external force is applied, making them resistant to noise and preventing signal wire breakage or short circuit accidents. There is no such thing.

[Brief explanation of the drawing]

The figures show one embodiment of this invention, with Fig. 1 being a front view showing the entire magnetic sensor and showing the state in which it is attached to a base, Fig. 2 being 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, 1 is the case body, 13 is the second locking part, 15 is the magnet, 16
1 is a coil, 18 is a shielded wire, and 29 is a conductive coating.

Claims (1)

[Claims for Utility Model Registration] A magnetic device consisting of a synthetic resin case body and a cover plate with a combination structure in the shape of a keyhole, with a magnet storage part, a coil storage part, and a signal line lead-out part provided in the circular part and the rectangular part, respectively. Constructing a sensor case, and shielding a cylindrical permanent magnet housed in the magnet housing, a ring coil housed in the coil housing, a signal line connected to the ring coil, and the signal line. The lead-out portion of the magnetic sensor case includes a shield conductive wire made of a shield wire and led out from the lead-out portion, and a conductive coating that covers the outer peripheral surface of the magnetic sensor case and is electrically connected to the shield wire. Inverted U with shield wire on both sides
1. A magnetic sensor characterized in that a locking portion is provided for locking separately in a letter shape, and a shield wire is locked by the locking portion.