JP2005049285A - Magnetic sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic sensor of a simple assembling structure with high detection precision. <P>SOLUTION: A magnetic sensor A comprises a magnetic head 1, composed of a magnet 11 for emitting magnetism and a magnetism detecting element 12 for detecting changes in the magnetism, an inner housing 3 which comprises a head part 31 for arranging the magnet 11 so as to overlap with the magnetism-detecting element 12, and an outer housing provided with a housing part 43 for housing the head part 31 provided with the magnetic head 1. The outer housing 4 is provided with a holding part 46 which abuts with the magnet 11, when assembled to the inner housing 3, for aligning the magnetic head 1 with the outer housing 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a magnetic sensor that detects a moving state of a detection object such as a gear or a multipolar magnet.

  As a magnetic sensor for detecting the rotation of a detected object such as a gear or a multipolar magnet (magnet), a magnet and a Hall IC are provided in a cylindrical resin case having a detection surface for detecting the detected object. And a magnetic head composed of magnetic detection means such as a magnetoresistive element, and the resin case is filled with a filling member (sealing member) such as epoxy to store the magnetic head in an airtight manner. Are known. Such a magnetic sensor is disclosed in Patent Document 1.

Such a magnetic sensor has a structure that hermetically seals the stored matter such as the magnetic head by filling the resin case with the filling member and curing.
JP-A-2-264817

  By the way, the arrangement position of the magnetic head portion with respect to the resin case has a great influence on the detection accuracy, so that it has to be assembled at an appropriate position. However, there is a possibility that the position of the magnetic head is shifted from a desired position with respect to the resin case, for example, at the time of assembling or after the filling member is filled and cured. Thus, when the magnetic head is in a misaligned state, there is a problem that the detection accuracy is lowered.

  Therefore, the present invention has been made paying attention to the above-described problems, and an object thereof is to provide a magnetic sensor having a good detection accuracy while having a simple assembly structure.

  According to the magnetic sensor of the present invention, as described in claim 1, the magnetic head having a magnet for generating magnetism and the magnetic change detecting means for detecting the magnetic change, and the magnet and the magnetic change detecting means overlap. A magnetic sensor comprising: an inner housing having a mounting portion for arranging the inner housing; and an outer housing provided with a storage portion that holds the inner housing and can store the mounting portion on which the magnetic head is disposed. The outer housing is provided with a holding portion that contacts the magnet and positions the magnetic head with respect to the outer housing when the inner housing is assembled.

  According to a second aspect of the present invention, in the magnetic sensor according to the first aspect, the outer housing is formed corresponding to the shape of the inner housing, and the inner housing is placed at a predetermined position of the outer housing. A guide portion for guiding is provided.

  According to a third aspect of the present invention, in the magnetic sensor according to the second aspect, the holding portion is provided in the guide portion, and the magnet and the magnet are formed by assembling the inner housing to the outer housing. The magnetic change detecting means is provided so as to be positioned.

  According to a fourth aspect of the present invention, in the magnetic sensor according to the second or third aspect, the storage portion of the outer housing is mainly composed of a bottom portion and a side wall, A guide portion, the holding portion, and a detection portion that performs magnetic detection by the magnetic head are provided.

  According to a fifth aspect of the present invention, in the magnetic sensor according to the fourth aspect, the magnetic head is positioned so as to be sandwiched between the detection unit and the holding unit. It is.

  The present invention relates to a magnetic sensor that detects a moving state of a detection object such as a gear or a multi-pole magnetized magnet, and can provide a magnetic sensor with good detection accuracy while having a simple assembly structure.

  Hereinafter, an example of the magnetic sensor of the present invention will be described with reference to the accompanying drawings.

  In FIG. 1, the magnetic sensor A is mainly composed of a magnetic head 1, a circuit board 2, an inner housing 3, an outer housing 4, and a filling member 5. In the magnetic sensor A, the magnetic head 1 and the circuit board 2 are arranged in the inner housing 3, and the arrangement place of the magnetic head 1 and the circuit board 2 in the inner housing 3 is accommodated in the outer housing 4. 3 and the outer housing 4 are assembled so that the filling member 5 is provided in the gap.

  As shown in FIG. 2, the magnetic head 1 includes a magnet (magnet) 11 and a magnetic detection element (magnetic change detection means) 12. The magnet 11 has a cylindrical shape and has a flat surface 11 a that contacts the magnetic detection element 12. The magnetic detection element 12 is applicable to a Hall IC and detects a change in magnetism (change in magnetic flux density). In this case, the magnetic detection element 12 is provided between the outer housing 4 and the magnet 11 so as to overlap and contact the flat surface 11 a of the magnet 11. The magnetic sensor A is attached in the vicinity of a detection object (not shown) made of a magnetic material so that the magnetic detection element 12 can detect a magnetic change between the moving detection object and the magnet 11. I have to.

  The circuit board 2 is made of an insulating substrate such as a glass cloth base epoxy resin or ceramic, and is a rigid circuit board in which a predetermined wiring pattern is formed, or a flexible circuit in which a predetermined wiring pattern is formed on a flexible material. A substrate (FPC) can be applied. On the circuit board 2, various electronic components (not shown) such as a noise absorbing capacitor and a signal amplifier circuit are mounted on the magnetic detection element 12. The lead 12a of the magnetic detection element 12 is electrically connected to one end side of the circuit board 2 via solder or the like, and the wiring 21 is electrically connected to the other end side via solder or the like. . Therefore, the detection signal detected by the magnetic detection element 12 is transmitted from the circuit board 2 to the wiring 21 and can be extracted outside.

  Synthetic resin materials such as SPS, PBT, and PPS can be applied to the inner housing 3, and as shown in FIGS. 2 to 4, a head portion (attachment portion) 31, a substrate holding portion 32, and a groove portion 33 are integrated. In preparation.

  The head portion 31 is provided to house the magnetic head 1 near the tip of the inner housing 3, embeds (disposes) the magnet 11, and is a recess for positioning the magnetic detection element 12 so as to overlap the magnet 11. It is formed into a shape. Further, the head portion 31 is held at a position (predetermined position) where the magnetic detection surface 12b of the magnetic detection element 12 faces and comes into contact with a later-described side wall of the outer housing 4. A positioning portion 31 a for positioning the side surface of the magnetic detection element 12 is provided. In addition, an opening 31 b is formed on the bottom surface of the head portion 31, so that the magnet 11 disposed in the head portion 31 is partially cut away from the back side.

  The substrate holding part 32 is provided with a mounting surface 32 a for arranging the circuit board 2 and a holding piece 32 b for holding the circuit board 2 on one side of the inner housing 3. The circuit board 2 is disposed at a position where it does not contact the outer housing 4.

  The groove portion 33 is provided on the back surface side of the mounting surface 32 a of the inner housing 3, and is formed in a groove shape along the insertion direction of the inner housing 3 with respect to the outer housing 4. In addition, the groove part 33 is provided so that it may overlap with the opening part 31b location.

  A synthetic resin material similar to that of the inner housing 3 can be applied to the outer housing 4, and as shown in FIGS. 5 to 7, the cross-sectional shape is substantially U-shaped and has a cylindrical shape with one end opened. . The outer housing 4 is configured so that a part of the inner housing 3 (location where the magnetic head 1 and the circuit board 2 are disposed) can be stored in a storage space (storage portion) 43 surrounded by the side wall 41 and the bottom portion 42. Further, the side wall 41 of the outer housing 4 is formed such that a portion facing the magnetic detection surface 12b which is a non-contact surface with the magnet 11 of the magnetic detection element 12 is thinner than the bottom portion 42. The thin portion serves as the detection unit 44 of the magnetic sensor A.

  A guide piece (guide portion) 45 corresponding to the shape of the groove portion 33 of the inner housing 3 is formed on the inner wall portion of the outer housing 4. Thereby, when the inner housing 3 is assembled to the outer housing 4, the magnetic head 1 held by the head portion 31 can be guided to a predetermined position in the storage space 43 and positioned. Further, the guide piece 45 is provided with a rib (holding portion) 46 that comes into contact with the magnet 11 from the opening portion 31 b of the head portion 31. As a result, when the inner housing 3 is assembled to the outer housing 4, the magnet 11 and the magnetic detection element 12 can be sandwiched between the detection unit 44 and the rib 46 so as to be disposed at an appropriate position. Further, the rib 46 is provided so as to be deformable, and is formed so as to be crushed by the magnet 11 at the time of assembling. 11 and the magnetic detection element 12 can be securely press-fitted and held without rattling.

  As shown in FIGS. 5 and 6, the outer housing 4 is provided with an external mounting portion 47 for fixing the entire magnetic sensor A at a desired arrangement position. The external mounting portion 47 is insert-molded with a collar 47b made of a metal material having a mounting hole 47a.

  The filling member 5 can be applied with a slightly fluid epoxy resin or silicone resin, and is filled in a gap portion between the outer housing 4 and the inner housing 3 in the storage space S. The filling member 5 is injected from the bottom 42 side in a state where the inner housing 3 is assembled to the outer housing 4, and at least to a position where the magnetic head 1 and the circuit board 2 of the head portion 31 are embedded. The filling member 5 is hardened after being filled, so that the airtightness can be held and fixedly held with respect to the electronic components of the magnetic head 1 and the circuit board 2, and vibration resistance, cold resistance, heat resistance, water resistance, etc. This improves the durability.

  The magnetic sensor A is configured by the above-described units. The magnetic sensor A includes a magnetic head 1 having a magnet 11 that generates magnetism and a magnetic detection element 12 that detects a change in the magnetism, and a head portion that is disposed so that the magnet 11 and the magnetic detection element 12 overlap each other. The magnetic sensor A includes an inner housing 3 having an inner housing 3 and an outer housing 3 provided with a housing portion 43 that houses a head portion 31 in which the magnetic head 1 is disposed. When the housing 3 is assembled, a rib 46 is provided which contacts the magnet 11 and positions the magnetic head 1 with respect to the outer housing 4.

  Therefore, the magnetic head 1 can be easily held at an appropriate position with respect to the outer housing 4 only by assembling the inner housing 3 and the outer housing 4. That is, the filling member 5 can be filled with no variation in the distance between the magnet 11 and the magnetic detection element 12 and the distance between the magnetic detection surface 12b of the magnetic detection element 12 and the detection portion 44 of the outer housing 4. Therefore, the magnetic sensor A has a simple detection structure and good detection accuracy.

  Further, the outer housing 4 is provided with a guide piece 45 that is formed corresponding to the shape of the groove 33 of the inner housing 3 and guides the inner housing 3 to a predetermined position of the outer housing 4. The inner housing 3 can be easily positioned with respect to. In addition, it is possible to prevent erroneous assembly.

  Further, the rib 46 is provided on the guide piece 45, and is provided so as to position the magnet 11 and the magnetic detection element 12 by assembling the inner housing 3 to the outer housing 4. Even if the work is not performed, the magnetic head 1 can be attracted and held at an appropriate position with good detection accuracy only by assembling the inner housing 3 along the guide piece 45.

  The housing portion 43 of the outer housing 4 is mainly composed of a bottom portion 42 and a side wall 41, and on the side wall 41, a guide piece 45, a rib 46, and a detection unit 44 that performs magnetic detection by the magnetic head 1, The magnetic head 1 is positioned so as to be sandwiched between the detection unit 44 and the rib 46, so that the magnetic head 1 is accurately held at an appropriate position with a simple press-fitting structure. Therefore, it is possible to obtain the magnetic sensor A with good detection accuracy.

  In the embodiment of the present invention, the above-described magnetic sensor A has been described as an example. However, the present invention is not limited to this. For example, the outer housing has a prismatic structure, or a magnetic As a change detection means, not a Hall IC but a magnetoresistive element (MR element) is used, or a magnetic head can be positioned by contacting a magnet without using a holding portion such as a rib 46. The configuration can be variously modified as long as the same effect can be obtained.

Sectional drawing of the magnetic sensor in embodiment of this invention. Sectional drawing of the inner housing before assembling | attaching to the outer housing of embodiment same as the above. The top view of the inner housing of embodiment same as the above. The top view which shows the back surface side of the inner housing of embodiment same as the above. The upper top view of the outer housing of embodiment same as the above. AA sectional drawing in FIG. BB sectional drawing in FIG.

Explanation of symbols

1 Magnetic head 11 Magnet (magnet)
12 Magnetic detection element (magnetic change detection means)
2 Circuit board 3 Inner housing 31 Head part (mounting part)
33 Groove part 4 Outer housing 41 Side wall 42 Bottom part 43 Storage part 44 Detection part 45 Guide piece (guide part)
46 rib (holding part)

Claims (5)

A magnetic head having a magnet for generating magnetism and a magnetic change detecting means for detecting a change in magnetism; an inner housing having a mounting portion for arranging the magnet and the magnetic change detecting means to overlap; and An outer housing having an inner housing that holds an inner housing and accommodates the mounting portion on which the magnetic head is disposed;
The magnetic sensor according to claim 1, wherein the outer housing is provided with a holding portion that contacts the magnet and positions the magnetic head with respect to the outer housing when the inner housing is assembled.   2. The magnetism according to claim 1, wherein the outer housing is provided with a guide portion that is formed corresponding to a shape of the inner housing and guides the inner housing to a predetermined position of the outer housing. Sensor.   The holding part is provided in the guide part, and is provided so as to position the magnet and the magnetic change detecting means by assembling the inner housing to the outer housing. Item 3. The magnetic sensor according to Item 2. The storage part of the outer housing is mainly composed of a bottom part and a side wall,
The magnetic sensor according to claim 2, wherein the side wall is provided with the guide portion, the holding portion, and a detection portion that performs magnetic detection by the magnetic head. The magnetic sensor according to claim 4, wherein the magnetic head is positioned so as to be sandwiched between the detection unit and the holding unit.

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