JPH10253648A - Rotation detecting device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily position a bias magnet to a molded IC by sharing the molded IC when a plurality of arrangement shapes of a rotation detection device are available. SOLUTION: A housing groove part 2a which houses a bias magnet 6 is provided on one face side of a molded IC 2, and the position of the bias magnet 6 can be adjusted in the housing groove part 2a. The grove width of the housing groove part 2a is nearly equal to the width of the bias magnet 6, and the bias magnet 6 can be moved in the length direction of the housing groove part 2a. Thereby, the dislocation in the groove width direction of the housing groove part 2a can be eliminated, and the bias magnet 6 can be positioned easily to the molded IC 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation detecting device for detecting rotation information using a magnetoresistive element (hereinafter, referred to as MRE) that changes a resistance value based on a change in direction of a bias magnetic field, and a method of manufacturing the same. It is particularly suitable for use in wheel speed sensors.

[0002]

2. Description of the Related Art A rotation detecting device uses a bias magnet for generating a bias magnetic field toward a rotating gear-shaped magnetic rotor, and detects a change in the magnetic field direction of the bias magnetic field accompanying rotation of the rotor by an MRE. To detect the rotation state of the rotor. 2. Description of the Related Art Conventionally, in a rotation detecting device, a molded IC in which a MRE and a circuit board having a circuit for performing signal processing of an output from the MRE are integrated with a molding member is formed to facilitate assembly.

A bias magnet is bonded and fixed to a flat surface of the mold IC so that a bias magnetic field passes through the MRE in the mold IC, so that the positional relationship between the MRE and the bias magnet is optimized.

[0004]

However, depending on the place where the rotation detecting device is arranged, etc., due to the allowable space that can be arranged, as shown in FIG. On the other hand, in the case where the rotation detecting device must be arranged so that the circuit board 3 is vertical, or in the case where the circuit board 3 is parallel to the outer peripheral surface 1a of the rotor 1 as shown in FIG. In some cases, a rotation detection device must be provided.

[0005] Under such conditions, the optimal positional relationship between the bias magnet 6 and the MRE 4 differs.
That is, in FIG.
The position where the center line is shifted by the interval A is the optimum position, and FIG.
1 (b), the position where the center line of the bias magnet 6 is shifted from the MRE 4 by the interval B is the optimum position.
And MRE4 are different in positional relationship.

In such a case, the mold IC 2
The mold IC2
However, when the mold IC 2 is shared, it is not easy to position the bias IC 6 by displacing the bias magnet 6 on one flat surface of the mold IC 2. The present invention has been made in view of the above points, and in a case where there are a plurality of arrangements of rotation detecting devices, a mold IC is shared and a bias magnet is used in a mold I.
The purpose is to enable easy positioning at C.

[0007]

In order to achieve the above object, the following technical means are employed. According to the invention as set forth in claims 1 to 4, on one side of the mold IC (2),
A housing groove (2a) for housing the bias magnet (6) is provided, and the position of the bias magnet (6) can be adjusted in the housing groove (2a).

As described above, since the position of the bias magnet (6) can be adjusted in the accommodation groove (2a),
Even when there are a plurality of arrangements of the rotation detecting device, the position of the bias magnet (6) can be adjusted to a position corresponding to each arrangement. Thereby, the bias magnet (6)
Can be easily positioned on the mold IC (2).

According to the second aspect of the present invention, the first locking means (2b, 2b) provided on the mold IC (2) is provided.
c) and the second locking means (6a, 6b) provided on the bias magnet (6) are fitted and locked, thereby prohibiting the movement of the bias magnet (6) in the accommodation groove (2a). It is characterized by doing so. Accordingly, the movement of the bias magnet (6) in the accommodation groove (2a) is prohibited, so that the bias magnet (6) can be more easily positioned on the mold IC (2).

More specifically, as set forth in claim 3, a protrusion (2b, 2c) protruding from the mold IC (2) toward the housing groove (2a), and the protrusion (2b, 2c). Can function as the first and second locking means by the concave portions (6a, 6b) corresponding to the above. Further, when the accommodating groove (2a) has a tapered shape and the bias magnet (6) has a tapered shape corresponding to the shape of the accommodating groove (2a), the bias magnet in the accommodating groove (2a) may be provided. Since the movement of (6) can be prohibited, the bias magnet (6) can be more easily positioned on the mold IC (2).

According to the fifth aspect of the present invention, the magnetizing direction is set at a predetermined acute angle (θ) with respect to the circuit board (3) so that the bias magnetic field passes through the magnetoresistive element (4). The bias magnet (6) is characterized in that it is magnetized. Thus, by magnetizing the bias magnet (6), the bias magnet (6) can be shared by each arrangement. In addition, since the optimal position in each arrangement form can be matched by the magnetization direction of the bias magnet (6), in this case, the bias magnet (6) is more easily provided.
Can be positioned on the mold IC (2).

In the invention according to claim 6, the mold IC (2) is positioned with respect to the mold (30), and the bias magnet (6) is positioned with respect to the mold (30). A housing part (20) is formed by injecting resin into (30), and a bias magnet (6) and a mold IC (2) are sealed and fixed in the housing part (20).

As described above, if the mold IC (2) is positioned with respect to the mold (30) and the bias magnet (6) is positioned with respect to the mold (30), the mold IC (2) is consequently formed. , The bias magnet (6) is positioned. Therefore, if the bias magnet (6) and the mold IC (2) are sealed and fixed in the housing part (20), the bias magnet (6) can be easily attached to the mold IC.
(2) Positioning can be performed. Thus, positioning when forming the housing part (20) is also possible.

Specifically, the first and second fixing pins (31, 32) are fixed so that the mold IC (2) and the bias magnet (6) are fixed at fixed positions of the housing part (20).
These are fixed by the mold IC
If the recesses (2d, 6c) are formed in portions where the (2) and the bias magnet (6) are fixed, respectively, the bias magnet (6) is securely positioned on the mold IC (2) and the housing portion (20) It is enclosed in.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention. (First Embodiment) FIGS. 1A and 1B are schematic diagrams of a rotation detecting device.
(B). FIG. 1A is a schematic diagram of a case where a rotation detecting device is arranged so that a circuit board 3 built in a mold IC 2 is perpendicular to an outer peripheral surface 1a of a rotor 1 (hereinafter referred to as a rotor radial direction arrangement). FIG. 1B shows the arrangement of the rotation detecting device such that the circuit board 3 is parallel to the outer peripheral surface 1a of the rotor 1 and the longitudinal direction of the circuit board 3 is perpendicular to the rotor rotation direction. FIG. 4 is a schematic diagram of the case where the operation is performed (hereinafter, referred to as a rotor axial direction arrangement).

First, the basic configuration of the rotation detecting device will be described with reference to FIGS. 1 (a) and 1 (b). The rotation detector is
It comprises a sensing unit 10 for detecting rotation and a housing unit 20 covering the sensing unit 10.
The sensing unit 10 includes a molded IC 2 including a circuit board 3, an MRE 4, and a lead frame 5, and a bias magnet 6.
It is composed of The MRE 4 is incorporated in the circuit board 3, and the molded IC 2 is formed by molding the circuit board 3 and the lead frame 5 connected to the circuit board 3 with a mold resin. However, part of the lead frame 5 is exposed from the mold resin,
Connection with the outside is possible. Note that a signal processing circuit is formed on the circuit board 3 so that the signal from the MRE 4 is amplified and binarized.

Further, the bias magnet 6 used in each of the above arrangements
Both have a rectangular parallelepiped of approximately the same dimensions. The bias magnet 6 used for the rotor radial direction arrangement is magnetized in a direction parallel to the circuit board 3, and the bias magnet 6 used for the rotor axial direction and the rotor tangential direction arrangement is the circuit board 3.
Are magnetized in a direction perpendicular to. FIG. 1 (a),
(B) Mold IC in sensing part 10
FIG. 2 shows a separation diagram of the bias magnet 6 and the bias magnet 6.

As shown in FIG. 2, an accommodating groove 2a is formed on one side of the molded IC 2, and each bias magnet 6 is fixed to the accommodating groove 2a. The accommodation groove 2a formed in the mold IC 2 has a groove width Ss substantially equal to the width Sm of the bias magnet 6, and has a groove length Ls
Is longer than the length Lm of the bias magnet 6. Thereby, the bias magnet 6 can be moved in the length direction of the accommodation groove 2a while suppressing the displacement of the bias magnet 6 in the width direction of the accommodation groove 2a.

The molded IC 2 in which the circuit board 3 is incorporated, the bias magnet 6 and the lead frame 5 are provided so as to extend in the longitudinal direction of the housing section 20.
The lead frame 5 is connected to, for example, an electronic control device via a wire harness (not shown). Further, a magnetic sensing surface 20a is formed on the housing section 20, and the rotation detecting device is arranged with the magnetic sensing surface 20a facing the rotor 1. Note that a fixed portion 20b is formed in the housing portion 20, and the rotation detecting device is fixed to the bolt by the fixed portion 20b.

Here, from the relation of the magnetic efficiency of the bias magnet 6, the position of the bias magnet 6 with respect to the MRE 4 differs depending on whether the rotation detecting device is arranged in the rotor radial direction or in the rotor axial direction. . Specifically, in the case of the rotor radial arrangement, the bias magnetic field generated by the bias magnet 6 passes through the MRE 4,
Since the bias magnet 6 needs to be arranged farther from the rotor 1 than the MRE 4, the bias magnet 6 needs to be offset from the center line of the bias magnet 6 by a distance A in the longitudinal direction of the rotating substrate 2. Further, in the case of the arrangement in the rotor axial direction, a position where the MRE 4 is offset from the center line of the bias magnet 6 in the longitudinal direction of the circuit board 2 by an interval B (<interval A) is the optimum position.

As described above, since the bias magnets 6 can be selectively displaced by the accommodation groove portions 2a, the arrangements satisfying the positional relationship between the bias magnets 6 and the mold IC 2 in FIGS. 1A and 1B, respectively. In addition, since the deviation of the bias magnet 6 in the width direction of the groove is suppressed, the positional relationship between the bias magnet 6 and the MRE 4 can be prevented from occurring.

As described above, when the arrangement of the rotation detecting device is different, the bias magnet 6 and the MRE 4 can have an optimal positional relationship while using the mold IC 2 having the same configuration. Further, by changing the groove shape of the housing groove portion 2a, the mold IC 2 can be shared in an arrangement other than the above-described arrangement in the rotor axial direction and the arrangement in the rotor radial direction. For example, in FIG. 3A, the rotation detection device is arranged such that the circuit board 3 is parallel to the outer peripheral surface 1a of the rotor 1 and the longitudinal direction of the circuit board 3 is parallel to the rotor rotation direction. A schematic diagram of the case (hereinafter referred to as rotor tangential arrangement) is shown.

In such an arrangement, a position where the center line of the bias magnet 6 and the MRE 4 coincide (interval C
= 0), and the position where the bias magnet 6 is slightly shifted in the axial direction from the housing groove 2a is the optimum position. In this case, the mold IC 2 cannot be moved in the accommodation groove 2a described above, but the mold IC 2 can be shared even in the rotor tangential arrangement by providing a cutout in the mold IC 2 in a portion where the bias magnet 6 is to be shifted. .

FIG. 3B shows a specific arrangement when the rotation detecting device is arranged in the tangential direction of the rotor. In this drawing, the rotation detecting device is applied to a wheel speed sensor in a vehicle. The wheel speed sensor is a drive shaft 50
In some vehicles, the rotation detecting device may be arranged in a specific arrangement (for example, a rotor tangent as shown in FIG. Direction), there is a case where a rotation detecting device having a configuration corresponding to various arrangements is required. However, under such conditions, the mold I having the same configuration is required.
The cost can be reduced because the bias magnet 6 can be fixed at the optimum position while using C2.

(Second Embodiment) In this embodiment,
Mold IC 2 and bias magnet 6 in first embodiment
By changing the shape of the mold IC2 having the same configuration.
Of these, the bias magnet 6 can be easily positioned at an optimum position according to the arrangement of the rotation detecting device.

FIG. 4A is a perspective view of the mold IC 2 in the present embodiment. FIGS. 4B and 4C are perspective views of the bias magnet 6 when the rotation detecting device is arranged in the rotor radial direction and the rotor axial direction, respectively. As shown in FIG. 4A, an accommodation groove 2a is formed in the molded IC 2, and a protrusion 2b is further provided on a side surface of the accommodation groove 2a in the length direction of the groove. As shown in FIGS. 4B and 4C, the bias magnet 6 is formed with a concave portion 6a corresponding to the convex portion 2b. Are positioned on the mold IC2.

At this time, as shown in FIGS. 4B and 4C, the position of the concave portion 6a formed in the bias magnet 6 is shifted depending on the arrangement of the rotation detecting device, and the bias magnet 6 is positioned on the mold IC 2. In this case, the positions are offset by the predetermined intervals A and B, respectively. This makes it possible to easily position the bias magnet 6 on the mold IC 2 and to eliminate the deviation of the bias magnet 6 in the length direction of the accommodation groove 2a.

(Third Embodiment) In this embodiment, as in the second embodiment, by changing the shapes of the mold IC 2 and the bias magnet 6 in the first embodiment, the rotation detecting device of the mold IC 2 having the same structure is used. The bias magnet 6 can be easily fixed at an optimum position according to the arrangement of the bias magnets.

FIG. 5A is a perspective view of the mold IC 2 in the present embodiment. FIGS. 5B and 5C are perspective views of the bias magnet 6 when the rotation detecting device is arranged in the rotor radial direction or the rotor axial direction, respectively. In the present embodiment, a convex portion 2c is formed on the bottom surface of the accommodation groove portion 2a, and a concave portion 6b corresponding to the convex portion 2c is formed on the bottom surface of the bias magnet 6. Thereby, the same effect as in the second embodiment can be obtained.

(Fourth Embodiment) In this embodiment, as in the second embodiment, by changing the shapes of the mold IC 2 and the bias magnet 6 in the first embodiment, the rotation detecting device of the mold IC 2 having the same configuration is used. The bias magnet 6 can be easily fixed at an optimum position according to the arrangement of the bias magnets.

FIG. 6A is a perspective view of the mold IC 2 in the present embodiment. FIGS. 6B and 6C are perspective views of the bias magnet 6 when the rotation detecting device is arranged in the rotor radial direction or the rotor axial direction, respectively. As shown in FIG. 6A, the shape of the accommodation groove 2a is tapered so that the groove width Ss contracts in the direction in which the bias magnet 6 comes off, and positioning in the length direction of the accommodation groove 2a becomes possible. ing. In this case, by adjusting the width Sm of the bias magnet 6 in the groove width direction of the housing groove 2a, the positional relationship between the bias magnet 6 and the MRE 4 can be optimized.

Thus, the same effect as in the second embodiment can be obtained. When the rotation detecting device is arranged in the rotor axial direction, the tip of the bias magnet 6 may protrude from the mold IC 2, so that the protruding portion is used to enhance the fitting property between the mold IC 2 and the bias magnet 6. The area for generating the bias magnetic field is increased.

(Fifth Embodiment) In this embodiment, the second to second embodiments
Mold I in the first embodiment as in the fourth embodiment
By changing the shapes of C2 and the bias magnet 6, the bias magnet 6 can be easily positioned at the optimum position according to the arrangement of the rotation detecting device in the mold IC 2 having the same configuration.

However, in the second to fourth embodiments, the unevenness corresponding to each of the mold IC 2 and the bias magnet 6 is adjusted so that the mold IC 2 and the bias magnet 6 are fitted without shifting the position before the housing 20 is formed. In contrast to this, the present embodiment is different in that the bias magnet 6 can be accurately positioned and fixed to the mold IC 2 when the housing portion 20 is formed.

FIG. 7 is a schematic diagram when the housing part 20 is molded by the molding die 30. After the mold IC 2 and the bias magnet 6 are placed in the mold 30, the mold 30
The rotation detecting device is completed by pouring the resin into the mold and filling the mold IC 2 and the like with the resin and molding the housing portion 20. At this time, generally, the mold IC 2
Is fixed so that no displacement occurs. In the present embodiment, the bias magnet 6 can be positioned and fixed to the mold IC 2 together with the fixing of the mold IC 2.

FIG. 8A is an enlarged view of the mold IC 2 in the present embodiment. FIGS. 8B and 8C are perspective views of the bias magnet 6 when the rotation detecting device is arranged in the rotor radial direction or the rotor axial direction. Hereinafter, the configurations of the mold 30 and the sensing unit 10 will be described with reference to FIGS. 7 and 8.

The molding die 30 is provided with a mold IC fixing pin 31 for fixing the mold IC 2 and a magnet fixing pin 32 for fixing the bias magnet 6. A concave portion 2d into which the molded IC fixing pin 31 is fitted is formed on both surfaces of the molded IC 2 which are fixed when the housing portion 20 is molded, and a magnet fixing pin 32 is formed on the upper surface of the bias magnet 6. A recess 6c to be fitted is formed. The positions of the recesses 6c formed in the bias magnet 6 are changed according to the respective arrangements, so that the bias magnet 6 can be fixed at the respective optimum positions.

That is, the mold 30 is
C2 is positioned and the bias magnet 6
As a result, the bias magnet 6 is positioned with respect to the mold IC 2. Therefore, the bias magnet 6 and the mold I
By enclosing and fixing C2, the bias magnet 6 can be easily positioned on the mold IC2.

As a result, the housing 20 is formed, and the bias magnet 6 is accurately positioned and fixed to the mold IC 2. The bias magnet 6 may be temporarily bonded in advance, but can be omitted because it can be fixed by the housing, and the step of bonding the bias magnet 6 to the mold IC 2 can be reduced.

(Sixth Embodiment) In the present embodiment,
By making the magnetizing direction of the bias magnet 6 oblique to the MRE 4, the mold IC 2 having the same configuration can be used. FIG. 9 shows an enlarged view of the sensing unit 10 in the present embodiment. As shown in FIG. 9, the bias magnet 6 is fixed at the accommodation groove 2a as in the first embodiment. Then, as indicated by the arrow in the figure, MRE4
, The bias magnet 6 is magnetized so as to generate a magnetic field obliquely.

FIGS. 10A and 10B are schematic diagrams showing a case where the sensing unit 10 shown in FIG. 9 is incorporated in a rotation detecting device in each arrangement. FIG. 10A shows a case where the rotation detecting device is arranged in the rotor radial direction, and FIG. 10B shows a case where the rotation detecting device is arranged in the rotor axial direction. As described above, different bias magnets 6 are used depending on the arrangement of the rotation detecting device. This is based on the magnetizing direction of the bias magnet 6. When the magnet is arranged in the radial direction of the rotor, the magnet magnetizing direction is parallel to the longitudinal direction of the circuit board 3, and the magnet is arranged in the axial direction of the rotor. Is a bias magnet 6 whose magnetization direction is perpendicular to the circuit board 3.
Is used.

In consideration of this, in the present embodiment, the bias magnet 6 is magnetized so as to generate a magnetic field obliquely to the MRE 4. Specifically, as shown by the arrow in FIG. 9, the bias magnet 6 is magnetized so as to generate a magnetic field that enters the circuit board 3 at a predetermined acute angle θ. Thus, the bias magnet 6
Is magnetized, the magnetic field can pass through the MRE 4 in each arrangement, so that the bias magnet 6
Can be shared in each arrangement.

In this case, although the optimum position of each arrangement is different depending on the magnetization direction, the bias magnet 6 can be easily positioned on the mold IC 2 by forming the accommodating groove 2a in the mold IC 2 as in the first embodiment. be able to. If the acute angle θ is set so that the optimum positions of the respective arrangement forms coincide with each other, the position of the bias magnet 6 does not need to be changed, so that the bias magnet 6 can be easily mounted on the mold IC.
2 can be positioned. In this case, since the optimum position is the same in each arrangement mode, the accommodation groove 2a may be set to a size in which the bias magnet 6 just fits.

(Other Embodiments) In the second and third embodiments, a convex portion is formed on the mold IC 2 and a concave portion is formed on the bias magnet 6 in order to position the bias magnet 6 on the mold IC 2. The same effect can be obtained by forming a protrusion on the bias magnet 6 and forming a recess on the mold IC 2.

[Brief description of the drawings]

FIGS. 1A and 1B are layout diagrams of a rotation detecting device according to an embodiment of the present invention, in which FIG. 1A shows a case of a rotor radial direction arrangement, and FIG. 1B shows a case of a rotor axial direction arrangement.

FIG. 2 is an exploded view of a sensing unit 10 used in the rotation detecting device shown in FIG.

FIG. 3A is an arrangement diagram in a case where the rotation detecting device is arranged in a tangential direction of a rotor, and FIG. 3B is a schematic diagram in a case where the rotation detecting device in the arrangement of FIG. FIG.

FIG. 4 is a perspective view of a sensing unit 10 according to a second embodiment.

FIG. 5 is a perspective view of a sensing unit 10 according to a third embodiment.

FIG. 6 is a perspective view of a sensing unit 10 according to a fourth embodiment.

FIG. 7 shows a housing part 20 in a molding die.
FIG. 3 is a schematic diagram showing a case where a bias magnet 6 is positioned on a mold IC.

FIG. 8 is a perspective view of a sensing unit 10 according to a fifth embodiment.

FIG. 9 is a perspective view of a sensing unit 10 according to a sixth embodiment.

10A and 10B are schematic diagrams when the sensing unit 10 shown in FIG. 9 is arranged in a rotation detection device, where FIG. 10A shows a case where the rotor is arranged in a radial direction, and FIG. is there.

FIG. 11 is a diagram showing an arrangement of a conventional rotation detecting device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Rotor, 1a ... Outer peripheral surface, 2 ... Mold IC, 2a,
... Accommodation groove, 2b, 2c ... convex, 2d ... concave, 3 ... circuit board, 4 ... MRE, 5 ... lead frame, 6 ... bias magnet, 6a, 6b, 6c ... concave, 10 ... sensing part,
20 ... Housing part.

Claims (6)

[Claims] 1. A bias magnet (6) arranged to face a rotating gear-shaped rotor (1) to generate a bias magnetic field toward the rotor (1), and by rotating the rotor (1). A mold IC (2) having a built-in magnetoresistive element (4) for detecting rotation of the rotor (1) based on a change in the generated bias magnetic field; and a surface of the mold IC (2). And a housing groove (2a) for adjusting the position of the bias magnet (6). 2. The mold IC (2) is provided with first locking means (2b, 2c), and the bias magnet (6) is provided with second locking means (6a, 6b). The first locking means (2b, 2c) and the second locking means (6a, 6b) are fitted and locked, so that the bias magnet ( 2. The rotation detecting device according to claim 1, wherein the movement of (6) is prohibited. 3. The mold according to claim 1, wherein the first locking means is a mold.
C (2) are projections (2b, 2c) protruding toward the accommodation groove (2a), and the second locking means is provided with a recess (6) corresponding to the projection.
The rotation detecting device according to claim 2, wherein the rotation detecting device is a, 6b). 4. The device according to claim 1, wherein the receiving groove has a tapered shape, and the bias magnet has a tapered shape corresponding to the shape of the receiving groove. The rotation detecting device as described in the above. 5. The bias magnet (6) in a direction forming a predetermined acute angle (θ) with the circuit board (3) so that the bias magnetic field passes through the magnetoresistive element (4).
The rotation detecting device according to claim 1, wherein the rotation detecting device is magnetized. 6. A bias magnet (6) for generating a bias magnetic field, and a molded IC (2) having a built-in magnetoresistive element (4) for detecting rotation of a rotor (1) based on a change in the bias magnetic field. A step of inserting the mold IC (2) into the molding die (30) of the housing part (20); a step of positioning the mold IC (2) with respect to the molding die (30); Positioning the magnet (6); and injecting resin into the mold (30) to form a housing part (20), and the housing part (20).
Inside the bias magnet (6) and the mold IC (2)
And a step of sealing and fixing the rotation detecting device.