Sensor device

Abstract

In a sensor device according to the present invention, an IC chip detects magnetic force. The IC chip is disposed between an upper wall and a lower wall of a magnet, and a covering body covers the IC chip. Here, a fixed lead is fixed to the covering body, and the magnet is fixed to the fixed lead. Therefore, the size of the sensor device can be reduced.

Description

Sensor Device

[0001] The present invention relates to a sensor device in which a sensor detects magnetic force.

[0002] In the rotation detection magnetic sensor described in JP-A-2004-233103, a magnetoresistive element is provided on an IC chip, a lead frame is electrically connected to the IC chip, and a first molding resin covers the IC chip and the lead frame.

[0003] In this rotation detection magnetic sensor, the IC chip is disposed within the magnet, and the magnet is fixed to the outer periphery of the first molding resin.

[0004] In consideration of the above, an object of the present invention is to provide a sensor device that can be miniaturized.

[0005] A sensor device of a first aspect of the present invention comprises a sensor that detects magnetic force, a magnet having a pair of magnetic pole portions with the sensor disposed between the pair of magnetic pole portions, a covering portion that covers the sensor, and a fixing portion that is fixed to the covering portion and to which the magnet is fixed.

[0006] A sensor device according to a second aspect of the present invention is the sensor device according to the first aspect of the present invention, further comprising a fitting hole provided in the magnet, into which the fixing portion is fitted.

[0007] A sensor device according to a third aspect of the present invention is the sensor device according to the first or second aspect of the present invention, wherein a pair of the fixing portions is provided, and the magnet is press-fitted between the pair of the fixing portions.

[0008] A sensor device according to a fourth aspect of the present invention is the sensor device according to any one of the first to third aspects of the present invention, wherein the pair of magnetic pole portions have the same magnetic polarity.

[0009] A sensor device according to a fifth aspect of the present invention is the sensor device according to any one of the first to fourth aspects of the present invention, wherein the covering portion covers the magnet.

[0010] In the sensor device according to the first aspect of the present invention, the sensor detects a magnetic force. The sensor is disposed between a pair of magnetic poles of a magnet, and the covering covers the sensor.

[0011] Here, the fixing portion is fixed to the covering portion, and the magnet is fixed to the fixing portion, which allows for miniaturization, unlike when the magnet is fixed to the outer periphery of the covering portion.

[0012] In the sensor device according to the second aspect of the present invention, the fixing portion is fitted into the fitting hole of the magnet, which allows for high positional accuracy of the magnet.

[0013] In the sensor device according to the third aspect of the present invention, a pair of fixing portions is provided, and the magnet is press-fitted between the pair of fixing portions, so that the magnet can be easily fixed to the fixing portions.

[0014] In the sensor device according to the fourth aspect of the present invention, the pair of magnetic pole portions have the same magnetic polarity, which allows the pair of magnetic pole portions to significantly change the magnetic force in the sensor, thereby effectively increasing the sensitivity of the sensor to detect magnetic force.

[0015] In the sensor device according to the fifth aspect of the present invention, the covering covers the magnet, so that the covering can cover the sensor and the magnet, simplifying the configuration.

[0016] 1 is a perspective view of the entire sensor device according to a first embodiment of the present invention, as seen from the diagonal left front; FIG. 2 is a perspective view of the sensor device according to the first embodiment of the present invention, as seen from the diagonal left rear, showing a state in which a cover has been removed; FIG. 3 is a perspective view of the sensor device according to the first embodiment of the present invention, as seen from the diagonal rear left, showing a state in which a cover has been provided during manufacturing; FIG. 4 is a perspective view of the sensor device according to the first embodiment of the present invention, as seen from the diagonal rear left, showing a state in which a cover has not been provided during manufacturing; FIG. 5 is a perspective view of the sensor device according to the first embodiment of the present invention, as seen from the diagonal rear left, showing a state in which a cover has been provided during manufacturing; FIG. 6 is a top view of the sensor device according to the first embodiment of the present invention, as seen from above, showing a state in which the sensor device according to the first embodiment of the present invention is manufactured; FIG. 7 is a perspective view of the entire sensor device according to a second embodiment of the present invention, as seen from the diagonal left front; FIG. 8 is a perspective view of the sensor device according to the second embodiment of the present invention, as seen from the diagonal left front; FIG. 9 is a top view of the sensor device according to the second embodiment of the present invention, as seen from above, showing a state in which the cover has been removed;

[0017] 1A shows a perspective view of a sensor device 10 according to a first embodiment of the present invention as seen diagonally from the front left, and FIG. 1B shows a perspective view of the main parts of the sensor device 10 as seen diagonally from the front left. In the drawings, the front of the sensor device 10 is indicated by an arrow FR, the right of the sensor device 10 is indicated by an arrow RH, and the top of the sensor device 10 is indicated by an arrow UP.

[0018] 1B, a substantially rectangular plate-shaped substrate 12 (see FIGS. 3A and 3B) is provided in the front portion of the sensor device 10 according to this embodiment. When the sensor device 10 is manufactured, the substrate 12 is provided in a substantially rectangular plate-shaped lead frame 14 (see FIGS. 2A and 2B) made of metal as a base material, and the substrate 12 is formed in the front portion of the lead frame 14.

[0019] 1A and 1B , a first lead 16, a second lead 18, a third lead 20, and a dummy lead 22 (see FIGS. 3A and 3B ) each having a long, substantially rectangular column shape are provided as extensions at the left end, right end, near the right end, and near the left end of the sensor device 10, and the first lead 16, the second lead 18, and the third lead 20 extend rearward from the substrate 12 side. The first lead 16 is electrically connected to the substrate 12 via a capacitor 24, and the second lead 18 is electrically connected directly to the substrate 12. The third lead 20 is electrically connected to the substrate 12 via a capacitor 26 and the second lead 18, and the dummy lead 22 is not electrically connected to the substrate 12.

[0020] The first lead 16, the second lead 18, the third lead 20, and the dummy lead 22 are respectively cut off from the first lead portion 16A, the second lead portion 18A, the third lead portion 20A, and the dummy lead portion 22A (see FIGS. 2A and 2B ) within the lead frame 14. The front end and middle portion of the first lead portion 16A are connected to the left portion of the lead frame 14, and the rear end of the first lead portion 16A is connected to the rear portion of the lead frame 14. The front end and middle portion of the second lead portion 18A are connected to the right portion of the lead frame 14, and the rear end of the second lead portion 18A is connected to the rear portion of the lead frame 14. The middle portion of the third lead portion 20A is connected to the second lead portion 18A, and the rear end of the third lead portion 20A is connected to the rear portion of the lead frame 14. The middle portion of the dummy lead portion 22A is connected to the first lead portion 16A, and the rear end of the dummy lead portion 22A is connected to the rear portion of the lead frame 14.

[0021] A pair of fixed leads 28 (see FIGS. 3A and 3B ) having a generally rectangular columnar shape are provided as fixed portions and extending portions in the left-right middle portion of the sensor device 10, and the pair of fixed leads 28 extend rearward from the substrate 12 without being connected to the substrate 12, and are opposed to each other in the left-right direction. A protruding portion 30 having a trapezoidal plate-like cross section is integrally formed on the inner left-right surfaces of the pair of fixed leads 28, and the rear side of the protruding portion 30 is an inclined surface 30A that is inclined inward in the left-right direction of the pair of fixed leads 28 as it extends forward.

[0022] The pair of fixed leads 28 are cut off from a pair of fixed lead portions 28A (see FIGS. 2A and 2B) in the lead frame 14. The middle portion and rear end of the left fixed lead portion 28A are connected to the dummy lead portion 22A, and the middle portion and rear end of the right fixed lead portion 28A are connected to the third lead portion 20A.

[0023] A substantially rectangular plate-shaped IC chip 32 (see FIGS. 3A and 3B ) serving as a sensor is fixed to the front portion of the upper surface of the substrate 12. The IC chip 32 is configured such that, for example, four magnetoresistive elements form a bridge circuit, and the IC chip 32 detects magnetic force (the direction of magnetic field lines) at its position. A first lead 16, a second lead 18, and a third lead 20 are electrically connected to the IC chip 32, and the first lead 16, the second lead 18, and the third lead 20 are used to supply power to the IC chip 32, to ground it, and to output detection signals, respectively.

[0024] A magnet 34 (see FIGS. 3A and 3B ) with a U-shaped cross section is provided around the periphery of the substrate 12. The rear wall of the magnet 34 has a substantially rectangular columnar shape and abuts against the rear end surface of the substrate 12 from the rear side, and the upper and lower walls 34A and 34B of the magnet 34, which serve as magnetic pole portions, extend forward above and below the substrate 12, respectively. The upper and lower walls 34A and 34B face each other in the vertical direction, and the entire IC chip 32, except for its front end, is located in the vertical center of the opposing range between the upper and lower walls 34A and 34B. The front ends of the upper and lower walls 34A and 34B of the magnet 34 are north poles, and the rear end of the rear wall of the magnet 34 is south poles.

[0025] Guide grooves 36, each having a rectangular cross section, are formed on the left and right surfaces of the rear wall of the magnet 34 near the lower center in the vertical direction, as fitting holes. The guide grooves 36 extend in the front-rear direction and are open to the front and rear. The fixed lead 28 is inserted into the guide grooves 36, and the fixed lead 28 is fitted into the guide grooves 36 in the vertical direction.

[0026] When the magnet 34 is assembled, the magnet 34 is inserted from the rear between the pair of fixed lead portions 28A of the lead frame 14, and each fixed lead portion 28A is inserted into the respective guide grooves 36 of the magnet 34, and each guide groove 36 slides relative to each fixed lead portion 28A. Furthermore, the bottom surface of each guide groove 36 abuts against the protruding end surface from the inclined surface 30A of the protruding portion 30 of each fixed lead portion 28A, causing the pair of fixed lead portions 28A to elastically tilt outward in the left-right direction, thereby press-fitting the magnet 34 between the pair of fixed lead portions 28A, and the magnet 34 is fixed (sandwiched) to the pair of fixed lead portions 28A by the elastic force (elastic restoring force) of the pair of fixed lead portions 28A.

[0027] The first lead 16, the second lead 18, the third lead 20, the front parts of the dummy lead 22, the capacitors 24, 26, the substrate 12, the IC chip 32, the fixed lead 28, and the magnet 34 are covered (sealed) by a resin, approximately rectangular parallelepiped covering body 38 (package) which serves as a covering part.

[0028] When the cover 38 is provided, the cover 38 is molded on the lead frame 14 with the front portions of the first lead portion 16A, second lead portion 18A, third lead portion 20A, dummy lead portion 22A, and fixed lead portion 28A, capacitors 24, 26, substrate 12, IC chip 32, and magnet 34 arranged inside. After the cover 38 is molded, the first lead 16, second lead 18, third lead 20, dummy lead 22, and fixed lead 28 are cut off from the lead frame 14. Note that the first lead 16, second lead 18, third lead 20, dummy lead 22, and fixed lead 28 are made of the same material because they are cut off from the lead frame 14.

[0029] Next, the operation of this embodiment will be described.

[0030] In the sensor device 10 configured as described above, the IC chip 32 detects magnetic force. Therefore, the IC chip 32 can detect, for example, the approach and movement of metal objects to and from the IC chip 32. Furthermore, the IC chip 32 is disposed between the upper wall 34A and the lower wall 34B of the magnet 34. Therefore, the magnetic field generated from the upper wall 34A and the lower wall 34B of the magnet 34 can change the magnetic force in the IC chip 32, thereby increasing the sensitivity with which the IC chip 32 detects magnetic force.

[0031] Incidentally, the cover 38 covers the IC chip 32 .

[0032] Here, the fixed lead 28 is fixed to the covering 38, and the magnet 34 is fixed to the fixed lead 28. Therefore, unlike when the magnet 34 is fixed to the outer periphery of the covering 38, the sensor device 10 can be made smaller.

[0033] Furthermore, the fixed lead 28 is fitted in the guide groove 36 of the magnet 34 in the vertical direction, which allows for high positional accuracy of the magnet 34 relative to the IC chip 32 in the vertical direction.

[0034] Furthermore, the magnet 34 is fitted between the pair of fixed lead portions 28 A. Therefore, the positional accuracy of the magnet 34 relative to the IC chip 32 in the left-right direction can be improved.

[0035] Furthermore, the substrate 12 is fixed to the cover 38, and the rear wall of the magnet 34 abuts against the substrate 12 in the front-rear direction. This allows for high positional accuracy of the magnet 34 relative to the IC chip 32 in the front-rear direction.

[0036] Furthermore, as the guide groove 36 of the magnet 34 slides relative to the fixed lead 28 (fixed lead portion 28A), the magnet 34 is guided by the fixed lead 28 (fixed lead portion 28A) and the magnet 34 is assembled to the fixed lead 28. This makes it easy to assemble the magnet 34 to the fixed lead 28.

[0037] Furthermore, the magnet 34 is press-fitted between the pair of fixed leads 28 (fixed lead portions 28A), so that the magnet 34 can be easily fixed to the fixed leads 28.

[0038] Furthermore, the upper wall 34A and the lower wall 34B of the magnet 34 have the same magnetic polarity (north pole), so that the magnetic field generated from the upper wall 34A and the lower wall 34B of the magnet 34 can significantly change the magnetic force in the IC chip 32, effectively increasing the sensitivity with which the IC chip 32 detects magnetic force.

[0039] Furthermore, the coating 38 covers the magnet 34. Therefore, the single coating 38 can cover the IC chip 32 and the magnet 34, simplifying the configuration.

[0040] In this embodiment, the fixed leads 28 are provided with the protrusions 30, so that the magnet 34 is press-fit between the pair of fixed leads 28 and fixed to the fixed leads 28. However, for example, the fixed leads 28 may not be provided with the protrusions 30, and the magnet 34 may be fixed to the fixed leads 28 with an adhesive.

[0041] [Second embodiment] Fig. 4A shows a perspective view of a sensor device 50 according to a second embodiment of the present invention as seen diagonally from the front left, and Fig. 4B shows a perspective view of the main parts of the sensor device 50 as seen diagonally from the front left. Furthermore, Fig. 5 shows a top view of the main parts of the sensor device 50 as seen from above.

[0042] The sensor device 50 according to this embodiment has almost the same configuration as that of the first embodiment, but differs in the following respects.

[0043] In the sensor device 50 according to this embodiment, a pair of fixed leads 28 are connected to the substrate 12 and extend rearward from the substrate 12 (see FIG. 4B). The pair of fixed leads 28 do not have protrusions 30 integrally formed on the inner left-right surfaces thereof, and the magnet 34 is not press-fit between the pair of fixed lead portions 28A. The magnet 34 is fixed to the pair of fixed lead portions 28A with an adhesive.

[0044] Here, this embodiment can also achieve the same effects and advantages as the first embodiment, except for the effects and advantages resulting from the magnet 34 being press-fitted between the pair of fixed lead portions 28A.

[0045] In the first and second embodiments, the magnet 34 is fixed to the fixed lead 28. However, the magnet 34 may be fixed to the first lead 16, the second lead 18, the third lead 20, the dummy lead 22, or the substrate 12.

[0046] In the first and second embodiments, the upper wall 34A and the lower wall 34B of the magnet 34 have the same magnetic polarity. However, the upper wall 34A and the lower wall 34B of the magnet 34 may have different magnetic polarities.

[0047] The disclosure of Japanese Patent Application No. 2024-8269, filed on January 23, 2024, is incorporated herein by reference in its entirety.

[0048] 10: Sensor device, 28: Fixed lead (fixed portion), 32: IC chip (sensor), 34: Magnet, 34A: Upper wall (magnetic pole portion), 34B: Lower wall (magnetic pole portion), 36: Guide groove (fitting hole), 38: Cover (cover portion), 50: Sensor device

Claims

1. A sensor device comprising: a sensor for detecting magnetism; a magnet provided with a pair of magnetic pole portions, the sensor being disposed between the pair of magnetic pole portions; a covering portion covering the sensor; and a fixing portion fixed to the covering portion and to which the magnet is fixed.

2. The sensor device according to claim 1, wherein the magnet is provided with a fitting hole into which the fixing portion is fitted.

3. The sensor device according to claim 1 or 2, wherein a pair of the fixing portions are provided, and the magnet is press-fitted between the pair of fixing portions.

4. The sensor device according to any one of claims 1 to 3, wherein the pair of magnetic pole portions have the same magnetic pole.

5. The sensor device according to any one of claims 1 to 4, wherein the covering portion covers the magnet.

6. The sensor device according to any one of claims 1 to 5, wherein the covering portion covers the fixing portion.

7. The sensor device according to any one of claims 1 to 6, further comprising a substrate to which the sensor is fixed.

8. The sensor device according to claim 7, wherein the magnet abuts against the substrate.

9. The sensor device according to claim 7 or 8, wherein the fixing portion is connected to the substrate.

10. The sensor device according to any one of claims 7 to 9, wherein the covering portion covers the substrate.

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