JP2005049095A - Magnetic sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic sensor with satisfactory detecting accuracy in spite of a simple built-up structure. <P>SOLUTION: The magnetic sensor A comprises a magnetic head 1 having at least a magnetic detecting means 12 for detecting a change in magnetic force and a magnet 11 generating the magnetic force; a circuit board 2 electrically connected to the magnetic detecting means 12; an inner housing 3 for arranging at least the magnetic head 1 and the circuit board 2 therein; an outer housing 4 having a housing space S for housing the magnetic head 1 and the circuit board 2; and a filling member 5 filled in the housing space S. The inner housing 3 is positioned and retained by the outer housing 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a magnetic sensor that detects a moving state of a detected object such as a gear or a multipolar magnet.
[0002]
[Prior art]
As a magnetic sensor for detecting the rotation of a detection object such as a gear or a multi-pole magnet, a magnet and a Hall IC or a magnetic resistance are provided in a cylindrical resin case having a detection surface for detecting the detection object. It is known that a magnetic head composed of magnetic detecting means such as an element is disposed and the magnetic head is hermetically accommodated by filling a filling member (sealing member) such as epoxy in the resin case. Yes. Such a magnetic sensor is disclosed in Patent Document 1.
[0003]
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.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 2-264817
[Problems to be solved by the invention]
By the way, the arrangement position of the magnetic head part with respect to the resin case has a great influence on the detection accuracy, and therefore it has been necessary to assemble it at an appropriate position. However, there is a possibility that the position where the magnetic head is disposed is displaced with respect to the resin case between the time when the filling member is filled and the time when the filling member is cured. Thus, when the magnetic head is in a misaligned state, there is a problem in that detection accuracy is lowered.
[0006]
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.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, a magnetic sensor according to the present invention includes, as described in claim 1, a magnetic detection unit that detects a change in magnetic force, a magnetic head having at least a magnet that generates the magnetic force, and the magnetic detection unit. An electrically connected circuit board, an inner housing in which at least the magnetic head and the circuit board are disposed, an outer housing having a storage section for storing the magnetic head and the circuit board, and filling the storage section The inner housing is positioned and held by the outer housing.
[0008]
Further, as described in claim 2, in the magnetic sensor according to claim 1, a mounting portion is provided on one side of the outer peripheral portion of the inner housing or the inner wall portion of the outer housing, and on the other side. A positioning holding part for holding the attachment part is provided.
[0009]
According to a third aspect of the present invention, in the magnetic sensor according to the second aspect, the positioning holding portion is provided so as to be positioned in the storage portion of the outer housing.
[0010]
According to a fourth aspect of the present invention, in the magnetic sensor according to the second or third aspect, at least one of the mounting portion and the positioning holding portion is a contact between the mounting portion and the positioning holding portion. A protruding portion for press-fitting is provided at the contact point.
[0011]
According to a fifth aspect of the present invention, in the magnetic sensor according to the third or fourth aspect, a guide portion that guides the mounting portion to the positioning holding portion is provided on the inner wall portion of the outer housing. It is characterized by.
[0012]
According to a sixth aspect of the present invention, in the magnetic sensor according to the second aspect, the positioning holding portion provided in the storage portion is provided in a plurality of stages, and the mounting portion provided in the inner housing is positioned and held. The magnetic detection surface of the magnetic head is provided so as to be movable up and down with respect to the detection surface of the outer housing.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of the magnetic sensor of the present invention will be described with reference to the accompanying drawings.
[0014]
A magnetic sensor according to a first embodiment of the present invention will be described with reference to FIGS. 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.
[0015]
The magnetic head 1 includes a magnet 11 and magnetic detection means 12. The magnet 11 has a cylindrical shape and has a flat surface 11 a that comes into contact with the magnetic detection means 12. The magnetic detection means 12 can be a Hall IC, a magnetoresistive element (MR element) or the like, and detects a change in magnetism generated by the magnet 11, and is disposed on the flat surface 11 a of the magnet 11.
[0016]
The rotating substrate 2 is made of an insulating substrate such as a glass cloth base epoxy resin or ceramic, and is a rigid circuit substrate on which a predetermined wiring pattern is formed, or a flexible circuit on 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 means 12. A lead 12a bent in a substantially L shape of the magnetic detection means 2 is electrically connected to one end side of the circuit board 2 via solder or the like, and a lead terminal described later is soldered to the other end side. Etc. are electrically connected to each other. Therefore, the detection signal detected by the magnetic detection means 2 is transmitted from the circuit board 2 to the lead terminal and taken out to the outside.
[0017]
A synthetic resin material such as SPS, PBT, and PPS can be applied to the inner housing 3, and as shown in FIGS. 2 and 3, a head portion (holding portion) 31, a body portion 32, and a mounting portion 33 are integrally provided. ing.
[0018]
The head portion 31 is provided with a concave portion 31a for embedding (arranging) the magnet 11 and a positioning portion 31b for positioning the magnetic detection means 12 on the distal end surface side of the inner housing 3, and the concave portion 31a and the positioning portion 31b. A mounting portion 31 for disposing the circuit board 2 is provided on the side portion close to. The circuit board 2 is provided at a position where it does not contact the outer housing 4. Further, as shown in FIG. 4, the positioning portion 31 b is held at a position (predetermined position) where the magnetic detection surface 12 b of the magnetic detection means 12 faces and abuts a bottom portion (described later) of the outer housing 4. Thus, the protrusions 31d for positioning the side surface of the magnetic detection means 12 are provided at a plurality of locations, and an opening that allows a part of the side surface of the magnetic detection means 12 to face between the respective protrusion pieces 31d. A portion 31e is provided. In addition, the head portion 31 is formed with a notch 31 f that opens part of the side surfaces of the magnetic detection means 12 and the magnet 11 and has a groove shape on the back side of the magnet 11. Further, the head portion 31 has a positional relationship in which the bottom surface of the recess 31a is substantially orthogonal to the placement portion 31c.
[0019]
A lead terminal 32a made of a conductive material is insert-molded in the body portion 32, and a connector portion 32b is provided at one end. The lead terminal 32a is bent and formed in a substantially L shape, and one end protrudes to the outside at the connector portion 32b, and the other end is drawn out so as to be electrically connected to the circuit board 2. Further, the body portion 32 is provided with a reinforcing portion 32c for guiding the lead portion 32a so as not to be deformed between both ends.
[0020]
The attachment portion 33 is provided on a side portion (outer peripheral portion) on the head portion 31 side (insertion direction side with respect to the outer housing 4) at a location different from the placement portion 31c on which the circuit board 2 is disposed, and protrudes. A plurality of flat plate-shaped members are formed.
[0021]
The outer housing 4 can be made of the same synthetic resin material as that of the inner housing 3 and has a cylindrical shape with a substantially U-shaped cross section and one end opened, and houses the magnetic head 1 and the circuit board 2. A storage space (storage section) S is configured.
The outer housing 4 is formed such that a bottom portion 4a that faces and contacts the magnetic detection surface 12b that is a non-contact surface with the magnet 11 of the magnetic detection means 12 is thinner than the side portion 4b. It becomes a detection surface of the magnetic sensor A.
[0022]
Further, as shown in FIGS. 5 and 6, a groove-shaped positioning holding portion 41 corresponding to the shape of the mounting portion 33 of the inner housing 3 is formed on the inner wall portion of the outer housing 4. The positioning holding portion 41 is formed with a deformable rib (press-fit protrusion) 41 a at the contact portion of the mounting portion 33. In addition, an oblique guide portion 41b having a wide opening end side is formed on the opening end side of the outer housing 4 continuously from the positioning holding portion 41, and the attachment portion 33 is guided into the groove portion of the positioning holding portion 41. Can do. Further, as shown in FIG. 7, the outer housing 4 is provided with an external mounting portion 42 for fixing the entire magnetic sensor A at a desired arrangement position. The external mounting portion 42 is insert-molded with a collar 42b made of a metal material having a mounting hole 42a.
[0023]
As the filling member 5, a somewhat fluid epoxy resin or silicone resin can be applied, and the filling space 5 is filled into the storage space S that becomes a gap between the outer housing 4 and the inner housing 3. The filling member 5 is injected from the bottom 4a side in a state where the outer housing 4 and the inner housing 3 are assembled, and at least a contact portion between the mounting portion 33 and the positioning holding portion 41 and the magnetic head 1 and the circuit board 2 are connected. Injection is performed up to the position where the arranged head portion 31 is embedded.
[0024]
When the filling member 5 is injected, the gap between the magnet 11 and the magnetic detection means 12 and the concave portion 31a of the inner housing 3 from the opening portion of the positioning portion 31b or the notch portion 31f provided in the inner housing 3. An airtight state is formed while the filling member 5 enters. 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.
[0025]
The magnetic sensor A is configured by the above-described units. The magnetic sensor A includes a magnetic head 1 having at least a magnetic detection means 12 for detecting a change in magnetic force and a magnet 11 for generating the magnetic force, a circuit board 2 electrically connected to the magnetic detection means 12, and the magnetic head 1. And an inner housing 3 in which at least the circuit board 2 is disposed, an outer housing 4 having a storage space S for storing the magnetic head 1 and the circuit board 2, and a filling member 5 filled in the storage space S. In the magnetic sensor A, a mounting portion 33 is provided on a side portion of the inner housing 3, and a positioning holding portion 41 that holds the mounting portion 33 is provided on an inner wall portion of the outer housing 4. Since the outer housing 4 is positioned and held, the mounting portion 33 and the positioning holding portion 41 The state in which the inner housing 3 is positioned with respect to the housing 4, that is, the state in which the magnetic detection means 12 positioned in the positioning portion 31 d of the inner housing 3 is not displaced with respect to the outer housing 4, that is, the magnetic detection means 12 Since the filling member 5 can be filled in a state in which the distance between the magnetic detection surface 12b and the bottom 4a of the outer housing 4 does not vary, the magnetic sensor A has a simple assembly structure and good detection accuracy. .
[0026]
Further, the positioning holding portion 41 is provided so as to be positioned in the storage space S of the outer housing 4, so that the gap between the attachment portion 33 and the positioning holding portion 41 can be filled with the filling member 5, and the curing is performed. Since the inner housing 3 can be firmly fixed and held with respect to the outer housing 4 by the filled member 5, the magnetic sensor A having high durability and good detection accuracy without causing positional deviation of the magnetic head 1 due to vibration or the like. It becomes.
[0027]
Further, at least one of the mounting portion 33 and the positioning holding portion 41 is provided with a rib 41a at a contact portion between the mounting portion 33 and the positioning holding portion 41, thereby preventing rattling during press-fitting. Since the stable state can be maintained well until the filling member 5 is filled or cured, the magnetic head 1 can be accurately arranged at a desired position with respect to the outer housing 4, and the detection accuracy is high. The magnetic sensor A is good.
[0028]
Moreover, since the guide part 41b which guides the attaching part 33 to the positioning holding part 41 is provided in the inner wall part of the outer housing 4, the attaching part 33 can be led into the positioning holding part 41, and thus the simple Assembling workability is improved.
[0029]
Further, since the mounting portion 33 is provided in the inner housing 3, the circuit board 2 does not contact (contact) the outer housing 4 that is easily affected by changes in the external environment such as external stress and outside air temperature. Thus, since the structure is such that stress and heat are not easily transmitted to the circuit board 2, the magnetic sensor A is highly durable.
[0030]
Next, a magnetic sensor according to a second embodiment of the present invention will be described with reference to FIG. 8. The same or corresponding parts as those in the first embodiment described above will be denoted by the same reference numerals and detailed description thereof will be given. Will be omitted. In the second embodiment, a magnetic sensor used for vehicle speed detection will be described as an example.
[0031]
The second embodiment is different from the magnetic sensor A in the first embodiment in the structure of the outer housing. Synthetic resin material similar to that of the outer housing 4 in the first embodiment described above can be applied to the outer housing 6. The outer housing 6 has a substantially U-shaped cross-section and has a cylindrical shape with one end opened. A storage space S for storing the inner housing 3 provided with the head 1 is provided. The outer housing 6 is formed such that a bottom portion 6a that contacts a magnetic detection surface that is a non-contact surface with the magnet 11 of the magnetic detection means 12 is thinner than the side portion 6b. It becomes the detection surface.
[0032]
In the outer housing 6, a positioning holding portion 61 for determining the position of the magnetic head 1 disposed in the inner housing 3 by determining the position of the inner housing 3 is formed. The positioning holding portion 61 is configured to support the mounting portions 33 provided at both end sides of the head portion 31 of the inner housing 3 and to be able to guide the magnetic head 1 to the detection surface that becomes the bottom surface 6 a of the outer housing 6. It is. The positioning holding parts 61 are provided with three pairs for moving the position of the magnetic head 1 up and down in order to adjust the relative positional relationship between the position of the magnetic head 1 and the detection target, The arrangement position of the magnetic head 1 can be determined with respect to the detection surface by selecting the insertion space between the portions 61.
[0033]
Further, the positioning holding portion 61 is provided with ribs 61a for holding the mounting portion 33 of the inner housing 3 by press-fitting on the upper surfaces of the first and second steps as viewed from the lower side in FIG. . The outer housing 6 is provided with an external mounting portion (not shown) on the peripheral wall in the same manner as in the first embodiment.
[0034]
The magnetic sensor A according to the second embodiment constitutes a positioning holding portion 61 provided in multiple stages, and the mounting portion 33 of the inner housing 3 is selectively provided with respect to the space between the plurality of positioning holding portions 61. Thus, the magnetic detection surface of the magnetic head 1 is provided so as to be movable up and down with respect to the detection surface of the outer housing 6.
[0035]
Therefore, the magnetic detecting element 12 in which two or more Hall elements and MR elements are arranged includes the arrangement position of the Hall elements and MR elements (hereinafter referred to as the position of the magnetic head 1), a gear, a rotor, and the like. In the magnetic sensor A, where it is desirable to align the position with the detected object, the mounting position of the magnetic sensor A is limited by providing the magnetic head 1 so as to be movable with respect to the detection surface. Even in the case where the detected object is disposed at a position shifted from the mounting position, the position of the magnetic head 1 and the position of the detected object are selected (adjusted). Since the relative positional relationship between the magnetic head 1 and the object to be detected can be set correctly, it is possible to detect an accurate change in magnetic force.
[0036]
Further, when such a magnetic sensor A is mounted on a vehicle, for example, even if the direction of the magnetic head 1 and the direction of the detected object are different for each vehicle type, the single outer housing 6 is used. It is possible to deal with a plurality of vehicle types, and the housing design can be simplified.
[0037]
In the first embodiment of the present invention, the magnetic sensor A described above has been described as an example. However, the present invention is not limited to this, and a filling member is provided in a space surrounded by the outer housing. What is necessary is just to be adapted to the magnetic sensor with which it is filled. Therefore, for example, the outer housing may have a prismatic structure, or three or more mounting portions 33 may be formed, or the deformable rib provided at the contact portion between the mounting portion and the positioning holding portion. (Press-fit protrusions) may be provided on the mounting portion side, and various modifications can be made to the configuration of the magnetic sensor as long as the same effect can be obtained.
[0038]
In the first embodiment described above, the mounting portion 33 is provided in the inner housing 3 and the positioning holding portion 41 corresponding to the mounting portion 33 is provided in the outer housing 4 as an example. The invention is not limited to this, for example, a configuration in which a flat plate-like mounting portion protruding on the inner wall portion of the outer housing 4 and a positioning holding portion for holding the mounting portion on the outer peripheral portion of the inner housing 3 are provided. However, the same effects as those of the above-described embodiment can be obtained.
[0039]
Further, with respect to the contact structure between the mounting portion and the positioning holding portion having a shape corresponding to the mounting portion, the assembly direction can be regulated by adjusting the formation positions of the mounting portion and the positioning holding portion, and the outer housing 4 It is possible to prevent an erroneous assembly of the inner housing 3 with respect to.
[0040]
Further, in the second embodiment of the present invention, the positioning holding portion 61 provided in multiple stages is configured. However, the mounting portion of the inner housing 3 is attached to the positioning holding portion 61 as in the first embodiment. A guide portion for guiding 33 may be provided. Further, the shape of the positioning holding portion 61 in the present invention is not limited to the above-described shape as long as the arrangement position of the magnetic head 1 is movable with respect to the detection surface of the outer housing 6. Absent.
[0041]
【The invention's effect】
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.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a main part of a magnetic sensor according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view showing an inner housing according to the embodiment.
FIG. 3 is a lower plan view showing the inner housing of the embodiment.
FIG. 4 is a plan view showing a head unit according to the embodiment.
FIG. 5 is a side view showing the opening side of the outer housing of the embodiment.
FIG. 6 is a side view showing the outer housing of the same embodiment in cross section.
FIG. 7 is a cross-sectional view showing the outer housing of the same embodiment in cross section.
FIG. 8 is a side view showing the outer housing in cross section in a second embodiment of the present invention.
[Explanation of symbols]
A Magnetic sensor 1 Magnetic head 11 Magnet 12 Magnetic detection means 2 Circuit board 3 Inner housing 31 Head part (holding part)
31a Recessed portion 31b Positioning portion 32 Body portion 32a Lead terminal 32c Reinforcing portion 33 Mounting portion 4, 6 Outer housing 41, 61 Positioning holding portion 41a, 61a Rib (protruding portion for press-fitting)
41b Guide part 5 Filling member

Claims (6)

Magnetic detection means for detecting a change in magnetic force, a magnetic head having at least a magnet for generating the magnetic force, a circuit board electrically connected to the magnetic detection means, and the magnetic head and the circuit board are disposed at least. A magnetic sensor comprising: an inner housing; an outer housing having a storage portion for storing the magnetic head and the circuit board; and a filling member filled in the storage portion,
The magnetic sensor according to claim 1, wherein the inner housing is positioned and held by the outer housing. The mounting portion is provided on one side of the outer peripheral portion of the inner housing or the inner wall portion of the outer housing, and the positioning holding portion that holds the mounting portion is provided on the other side. Item 2. The magnetic sensor according to Item 1. The magnetic sensor according to claim 2, wherein the positioning holding portion is provided so as to be positioned in the storage portion of the outer housing. 4. A press-fitting projecting portion is provided at at least one of the mounting portion and the positioning holding portion at a contact portion between the mounting portion and the positioning holding portion. The magnetic sensor described in 1. The magnetic sensor according to claim 3, wherein a guide portion that guides the attachment portion to the positioning holding portion is provided on an inner wall portion of the outer housing. By providing the positioning holding portions provided in the storage portion in a plurality of stages and selectively disposing the mounting portions provided in the inner housing with respect to the positioning holding portions, the magnetic detection surface of the magnetic head is provided. The magnetic sensor according to claim 2, wherein the magnetic sensor is provided so as to be movable up and down with respect to a detection surface of the outer housing.

Images