Sensor device

Abstract

To achieve miniaturization.SOLUTION: In a sensor device 10, an IC chip 32 detects magnetic force. The IC chip 32 is disposed between an upper wall 34A and a lower wall 34B of a magnet 34, and a covering body 38 covers the IC chip 32. A fixed lead 28 is fixed to the covering body 38, and the magnet 34 is fixed to the fixed lead 28. Therefore, the sensor device can be miniaturized.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In the rotational detection magnetic sensor described in Patent Document 1 below, a magnetoresistive element is provided on an IC chip, a lead frame is electrically connected to the IC chip, and a first mold resin covers the IC chip and the lead frame.

[0003] Here, in this rotational detection magnetic sensor, the IC chip is disposed within a magnet, and the magnet is fixed to the outer periphery of the first mold resin.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In consideration of the above facts, an object of the present invention is to obtain a sensor device that can be miniaturized.

Means for Solving the Problems

[0006] The sensor device according to the first aspect of the present invention includes a sensor that detects magnetic force, a magnet provided with a pair of magnetic pole portions, the sensor being 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.

[0007] The sensor device according to the second aspect of the present invention is the sensor device according to the first aspect of the present invention, and includes a fitting hole provided in the magnet and into which the fixing portion is fitted.

[0008] The sensor device according to the 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 are provided, and the magnet is press-fitted between the pair of the fixing portions.

[0009] The sensor device according to the 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 the magnetic pole portions are of the same magnetic pole.

[0010] The sensor device according to the 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.

Advantages of the Invention

[0011] In the sensor device according to the first aspect of the present invention, the sensor detects a magnetic force. Further, the sensor is disposed between a pair of magnetic pole portions of the magnet, and the covering portion covers the sensor.

[0012] Here, the fixing portion is fixed to the covering portion, and the magnet is fixed to the fixing portion. Therefore, unlike the case where the magnet is fixed to the outer periphery of the covering portion, miniaturization can be achieved.

[0013] 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. Therefore, the positional accuracy of the magnet can be increased.

[0014] In the sensor device according to the third aspect of the present invention, a pair of the fixing portions are provided, and the magnet is press-fitted between the pair of the fixing portions. Therefore, the magnet can be easily fixed to the fixing portion.

[0015] In the sensor device according to the fourth aspect of the present invention, the pair of the magnetic pole portions are of the same magnetic pole. Therefore, the magnetic force in the sensor can be greatly changed by the pair of the magnetic pole portions, and the sensitivity of the sensor for detecting the magnetic force can be effectively increased.

[0016] In the sensor device according to the fifth aspect of the present invention, the covering portion covers the magnet. Therefore, the covering portion can cover the sensor and the magnet, and the configuration can be simplified.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0018] [First Embodiment] In Fig. 1(A), the sensor device 10 according to the first embodiment of the present invention is shown in a perspective view as viewed from the front diagonally leftward, and in Fig. 1(B), the main part of the sensor device 10 is shown in a perspective view as viewed from the front diagonally leftward. In the drawings, the front of the sensor device 10 is indicated by the arrow FR, the right side of the sensor device 10 is indicated by the arrow RH, and the upper side of the sensor device 10 is indicated by the arrow UP.

[0019] As shown in FIG. 1(B), a substantially rectangular plate-shaped substrate 12 (see FIGS. 3(A) and (B)) is provided at the front portion of the sensor device 10 according to the present embodiment. When the sensor device 10 is manufactured, the substrate 12 is provided on a lead frame 14 (see FIGS. 2(A) and (B)) made of metal as a base material and having a substantially rectangular frame plate shape, and the substrate 12 is formed at the front portion within the lead frame 14.

[0020] As shown in FIGS. 1(A) and (B), long substantially rectangular columnar first leads 16, second leads 18, third leads 20, and dummy leads 22 (see FIGS. 3(A) and (B)) are provided as extending portions at the left end, right end, near the right end, and near the left end of the sensor device 10, respectively. The first leads 16, second leads 18, and third leads 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 directly electrically connected 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.

[0021] The first leads 16, second leads 18, third leads 20, and dummy leads 22 are respectively cut out from first lead portions 16A, second lead portions 18A, third lead portions 20A, and dummy lead portions 22A (see FIGS. 2(A) and (B)) within the lead frame 14. The front end and the intermediate 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 the intermediate 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 intermediate 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 intermediate 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.

[0022] At the middle part in the left - right direction of the sensor device 10, a pair of substantially rectangular column - shaped fixed leads 28 (see (A) and (B) of FIG. 3), which serve as a fixed part and an extending part, are provided. The pair of fixed leads 28 extend rearward from the substrate 12 side without being connected to the substrate 12 and are opposed to each other in the left - right direction. On the inner surfaces in the left - right direction of the pair of fixed leads 28, protruding portions 30 having a trapezoidal cross - sectional plate shape are integrally formed. The rear side surface of the protruding portion 30 is an inclined surface 30A, which is inclined in the direction of the inner side in the left - right direction of the pair of fixed leads 28 as it goes forward.

[0023] The pair of fixed leads 28 are cut from a pair of fixed lead portions 28A (see (A) and (B) of FIG. 2) in the lead frame 14. The middle part and the rear end of the left - hand fixed lead portion 28A are connected to the dummy lead portion 22A, and the middle part and the rear end of the right - hand fixed lead portion 28A are connected to the third lead portion 20A.

[0024] On the front - side portion of the upper surface of the substrate 12, a substantially rectangular plate - shaped IC chip 32 (see (A) and (B) of FIG. 3), which serves as a sensor, is fixed. The IC chip 32 is configured such that, for example, four magnetoresistive elements form a bridge circuit, and the IC chip 32 detects the magnetic force (the direction of magnetic field lines) at the arrangement position. The first lead 16, the second lead 18, and the 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 respectively used for power supply, grounding, and detection output with respect to the IC chip 32.

[0025] Around the substrate 12, a magnet 34 having a U-shaped cross section (see (A) and (B) of FIG. 3) is provided. The substantially rectangular columnar rear wall of the magnet 34 is in contact with the rear end surface of the substrate 12 from the rear side. The substantially rectangular columnar upper wall 34A and lower wall 34B as the magnetic pole portions of the magnet 34 extend forward on the upper side and the lower side of the substrate 12, respectively. The upper wall 34A and the lower wall 34B are opposed to each other in the vertical direction, and the entire part other than the front end portion of the IC chip 32 is disposed at the vertical center portion of the opposing range between the upper wall 34A and the lower wall 34B. The front ends of the upper wall 34A and the lower wall 34B of the magnet 34 are N poles, and the rear end of the rear wall of the magnet 34 is an S pole.

[0026] On the left and right surfaces of the rear wall of the magnet 34, in the vicinity of the lower side of the vertical center portion, a guide groove 36 having a rectangular cross section as a fitting hole is formed. The guide groove 36 extends in the front-rear direction and is open to the front side and the rear side. A fixing lead 28 is inserted into the guide groove 36, and the fixing lead 28 is fitted in the guide groove 36 in the vertical direction.

[0027] When the magnet 34 is assembled, the magnet 34 is inserted from the rear side between a pair of fixing lead portions 28A of the lead frame 14, and each fixing lead portion 28A is inserted into each guide groove 36 of the magnet 34, and each guide groove 36 is slid with respect to each fixing lead portion 28A. Further, the bottom surface of each guide groove 36 is brought into contact with the protruding end surface from the inclined surface 30A of the protruding portion 30 of each fixing lead portion 28A, and a pair of fixing lead portions 28A are elastically tilted outward in the left-right direction, so that the magnet 34 is press-fitted between the pair of fixing lead portions 28A, and the magnet 34 is fixed (clamped) to the pair of fixing lead portions 28A by the elastic force (elastic restoring force) of the pair of fixing lead portions 28A.

[0028] The front portions of the first lead 16, the second lead 18, the third lead 20, and the dummy lead 22, the capacitors 24, 26, the substrate 12, the IC chip 32, the fixing lead 28, and the magnet 34 are covered (sealed) by a resin-made substantially rectangular parallelepiped covering body 38 (package) as a covering portion.

[0029] When the covering 38 is provided, in the lead frame 14, the covering 38 is molded with the first lead portion 16A, the second lead portion 18A, the third lead portion 20A, the dummy lead portion 22A, and the front portion of the fixed lead portion 28A, the capacitors 24, 26, the substrate 12, the IC chip 32, and the magnet 34 disposed therein. After the covering 38 is molded, the first lead 16, the second lead 18, the third lead 20, the dummy lead 22, and the fixed lead 28 are cut off from the lead frame 14. Note that the first lead 16, the second lead 18, the third lead 20, the dummy lead 22, and the fixed lead 28 are made of the same material because they are cut off from the lead frame 14.

[0030] Next, the operation of this embodiment will be described.

[0031] In the sensor device 10 having the above configuration, the IC chip 32 detects magnetic force. Therefore, for example, the IC chip 32 can detect the approach and separation of a metal with respect to the IC chip 32. Further, 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, and the sensitivity of the IC chip 32 to detect magnetic force can be increased.

[0032] By the way, the covering 38 covers the IC chip 32.

[0033] Here, the fixed lead 28 is fixed to the covering 38, and the magnet 34 is fixed to the fixed lead 28. Therefore, unlike the case where the magnet 34 is fixed to the outer periphery of the covering 38, the sensor device 10 can be miniaturized.

[0034] Also, the fixed lead 28 is fitted in the guide groove 36 of the magnet 34 in the vertical direction. Therefore, the positional accuracy of the magnet 34 with respect to the IC chip 32 in the vertical direction can be increased.

[0035] Furthermore, a magnet 34 is fitted between a pair of fixed lead portions 28A. Therefore, the positional accuracy of the magnet 34 in the left - right direction with respect to the IC chip 32 can be improved.

[0036] Moreover, the substrate 12 is fixed to the covering body 38, and the rear wall of the magnet 34 is abutted against the substrate 12 in the front - rear direction. Therefore, the positional accuracy of the magnet 34 in the front - rear direction with respect to the IC chip 32 can be improved.

[0037] Also, by sliding the guide groove 36 of the magnet 34 with respect 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. Therefore, the magnet 34 can be easily assembled to the fixed lead 28.

[0038] Furthermore, the magnet 34 is press - fitted between a pair of fixed leads 28 (fixed lead portions 28A). Therefore, the magnet 34 can be easily fixed to the fixed lead 28.

[0039] Also, the upper wall 34A and the lower wall 34B of the magnet 34 are of the same magnetic pole (N - pole). Therefore, the magnetic force in the IC chip 32 can be greatly changed by the magnetic fields generated from the upper wall 34A and the lower wall 34B of the magnet 34, and the sensitivity of the IC chip 32 to detect the magnetic force can be effectively increased.

[0040] Furthermore, the covering body 38 covers the magnet 34. Therefore, a single covering body 38 can cover the IC chip 32 and the magnet 34, and the structure can be simplified.

[0041] In this embodiment, by providing the protruding portion 30 on the fixed lead 28, the magnet 34 is press - fitted between the pair of fixed leads 28, and the magnet 34 is fixed to the fixed lead 28. However, for example, even if the protruding portion 30 is not provided on the fixed lead 28, the magnet 34 may be fixed to the fixed lead 28 with an adhesive.

[0042] [Second Embodiment] FIG. 4(A) shows a perspective view of a sensor device 50 according to the second embodiment of the present invention as viewed from the front obliquely leftward, and FIG. 4(B) shows a perspective view of the main part of the sensor device 50 as viewed from the front obliquely leftward. Further, FIG. 5 shows a top view of the main part of the sensor device 50 as viewed from above.

[0043] The sensor device 50 according to the present embodiment has substantially the same configuration as the first embodiment, but is different in the following points.

[0044] In the sensor device 50 according to the present embodiment, a pair of fixed leads 28 are extended rearward from the substrate 12 side in a state of being connected to the substrate 12 (see FIG. 4(B)). Protrusions 30 are not integrally formed on the inner side surfaces in the left-right direction of the pair of fixed leads 28, and a magnet 34 is not press-fitted between the pair of fixed lead portions 28A. The magnet 34 is fixed to the pair of fixed lead portions 28A by an adhesive.

[0045] Here, also in the present embodiment, the same operations and effects as those of the first embodiment can be achieved except for the operations and effects caused by press-fitting the magnet 34 between the pair of fixed lead portions 28A.

[0046] In the first and second embodiments described above, 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.

[0047] Also, in the first and second embodiments described above, the upper wall 34A and the lower wall 34B of the magnet 34 are made of the same magnetic pole. However, the upper wall 34A and the lower wall 34B of the magnet 34 may be made of different magnetic poles.

Description of Reference Numerals

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

Claims

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

2. The sensor device according to Claim 1, further comprising a fitting hole provided in the magnet and into which the fixing portion is fitted.

3. The sensor device according to Claim 1, 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 Claim 1, wherein the pair of magnetic pole portions have the same magnetic pole.

5. The sensor device according to Claim 1, wherein the covering portion covers the magnet.

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