Sensor device

Abstract

This sensor device (30) comprises magnets (41-47) and a sensor unit (35). The magnet (41) is cylindrical and is magnetized in the axial direction. The sensor unit (35) is capable of detecting a change in magnetic flux due to a change in the relative position between the magnet (41) and a target (22) made of a magnetic material, and is disposed on one side of the magnet (41) in the axial direction. Each of hole parts (411, 421, 431, 441, 451, 461, 471) penetrating the magnet (41) in the axial direction is increased in diameter so that the inner diameter of an end on the side where the sensor unit (35) is disposed is larger than that of a small-diameter part (413, 423, 433, 443, 453) penetrating in the axial direction, respectively.

Description

Sensor device Cross-reference to related applications

[0001] This application is based on Patent Application No. 2024-230891 filed on December 26, 2024, the content of which is incorporated herein by reference.

[0002] This disclosure relates to a sensor device.

[0003] Conventionally, measuring devices for measuring changes in magnetic fields are known. For example, in Patent Document 1, the reference position is set as the magnetic flux maximum point, and when it becomes non-maximum, it is determined that the gear selector is no longer in the neutral position.

[0004] U.S. Patent No. 8,624,586

[0005] For example, in the case of a sensor device that detects changes in magnetic flux density using a Hall sensor or the like, when assembling the magnet and the sensor IC, the relative position may vary, and if the assembly error becomes large, there is a risk that the detection accuracy will deteriorate. The object of this disclosure is to provide a sensor device capable of relaxing the assembly accuracy.

[0006] The sensor device of this disclosure includes a magnet and a sensor unit. The cylindrical magnet is magnetized in the axial direction. The sensor unit can detect a change in magnetic flux due to a change in the relative position between a target formed of a magnetic material and the magnet, and is arranged on one side in the axial direction of the magnet. The hole portion penetrating in the axial direction of the magnet is enlarged in diameter such that the inner diameter of the end portion on the side where the sensor unit is arranged is larger than the small-diameter portion in the axial direction. Thereby, the assembly accuracy can be relaxed.

[0007] The above-mentioned objectives and other objectives, features and advantages of this disclosure will become clearer from the following detailed description with reference to the attached drawings. The drawings are as follows: Figure 1 is a cross-sectional view of a clutch device according to the first embodiment; Figure 2 is a schematic diagram showing the movable clutch, sensor unit and magnet according to the first embodiment; Figure 3 is a cross-sectional view showing the movable clutch, sensor unit and magnet according to the first embodiment; Figure 4 is a plan view showing the magnet according to the first embodiment; Figure 5 is an explanatory diagram illustrating the zero magnetic flux region when the taper angle of the magnet is 0°; Figure 6 is an explanatory diagram illustrating the zero magnetic flux region when the taper half-angle of the magnet is 45°; and Figure 7 is the zero magnetic flux region when the taper half-angle of the magnet is 60°. These are explanatory diagrams illustrating the following: Figure 8 is a cross-sectional view showing the movable clutch, sensor unit, and magnet according to the second embodiment; Figure 9 is a plan view showing the magnet according to the second embodiment; Figure 10 is a cross-sectional view showing the magnet according to the third embodiment; Figure 11 is a cross-sectional view showing the magnet according to the fourth embodiment; Figure 12 is a cross-sectional view showing the magnet according to the fifth embodiment; Figure 13 is a cross-sectional view showing the magnet according to the sixth embodiment; Figure 14 is a plan view showing the magnet according to the seventh embodiment; and Figure 15 is a plan view showing the magnet according to the eighth embodiment.

[0008] The sensor device described herein will be described below with reference to the drawings. In the following embodiments, substantially identical components will be denoted by the same reference numerals and their descriptions will be omitted.

[0009] (First Embodiment) The first embodiment is shown in Figures 1 to 7. As shown in Figure 1, the sensor device 30 is a stroke sensor applied to a clutch device 10 mounted on a vehicle such as an electric vehicle. The clutch device 10 includes a clutch housing 11, an actuator 15, a clutch unit 20, and the sensor device 30, etc.

[0010] The clutch housing 11 has a bottom portion 111 and a cylindrical portion 115, and is formed in a substantially bottomed cylindrical shape. A shaft holding portion 112 is formed in the bottom portion 111 so as to rise up on the opposite side of the opening. A shaft insertion hole 113 is formed in the shaft holding portion 112, through which a wheel shaft (not shown) is inserted. An oil seal 12 is provided between the wheel shaft and the clutch housing 11. In addition, a shaft insertion hole 114 is formed in the bottom portion 111 through which an actuator shaft 155 is inserted.

[0011] The actuator 15 is, for example, a solenoid and is housed in the actuator housing 151. The actuator shaft 155 is driven by an electric current. The tip of the actuator shaft 155 is inserted into the clutch housing 11 through the shaft insertion hole 114. The tip of the actuator shaft 155 is connected to the movable clutch 22 via the relay member 16.

[0012] The clutch section 20 includes a fixed clutch 21 and a movable clutch 22. The fixed clutch 21 has a fixed clutch cylinder 211, a fixed clutch plate 213, and fixed dog teeth 214, and is made of, for example, metal. One end of the fixed clutch cylinder 211 is inserted into an insertion hole 113 and is rotatably held in the clutch housing 11 by a bearing 26 fixed to the shaft holding section 112. The wheel shaft is inserted into and fixed to the fixed clutch cylinder 211.

[0013] The fixed clutch plate portion 213 is formed in an annular plate shape so as to extend radially outward from the fixed clutch cylinder portion 211. The fixed dog teeth 214 are formed on the side of the fixed clutch plate portion 213 opposite to the bearing 26.

[0014] The movable clutch 22 has a movable clutch cylinder portion 221, a movable clutch plate portion 223, and movable dog teeth 224 (see Figure 2), and is made of a magnetic material such as metal. A cylindrical transmission member 23 is inserted into and fixed to the movable clutch cylinder portion 221. The transmission member 23 has a fixed clutch cylinder portion 211 inserted into one end, and the other end is provided protruding from the clutch housing 11 and connected to a differential shaft (not shown). A bearing 27 is provided between the transmission member 23 and the fixed clutch cylinder portion 211, and the transmission member 23 is held so as to be rotatable relative to the fixed clutch 21.

[0015] The movable clutch plate portion 223 is formed in an annular shape extending radially outward at one axial end of the movable clutch cylinder portion 221. The movable clutch plate portion 223 is provided facing the fixed clutch plate portion 213. The movable dog teeth 224 are formed at the portion of the movable clutch plate portion 223 facing the fixed clutch plate portion 213 so as to be able to mesh with the fixed dog teeth 214.

[0016] A connecting groove 225 is formed on the outer circumferential surface of the movable clutch cylinder portion 221. A relay member 16 is fixed to the connecting groove 225. As a result, the movable clutch 22 is provided by the actuator 15 so as to be able to stroke in the axial direction.

[0017] The sensor device 30 is inserted into and fixed to a sensor mounting portion 117 formed on the peripheral wall of the clutch housing 11. The sensor device 30 includes a sensor housing 31, a connector housing 32, a circuit board 33, a sensor portion 35, and a magnet 41, etc.

[0018] The sensor housing 31 has a substrate holding portion 311 and a sensor holding portion 312, and is integrally formed from a non-magnetic material such as epoxy resin. The sensor holding portion 312 is formed to protrude from the substrate holding portion 311. Hereinafter, the side of the sensor holding portion 312 that protrudes will be referred to as the tip side. The sensor portion 35 and the magnet 41 are held at the tip side of the sensor holding portion 312.

[0019] The connector housing 32 has a sealing portion 321 and a connector portion 325, and is integrally formed from a non-magnetic resin or the like. The sealing portion 321 seals the tip side of the sensor housing 31. The sealing portion 321 is inserted into the sensor mounting portion 117 so that the sensor portion 35 and the magnet 41 face the movable clutch plate portion 223 of the movable clutch 22. The contact surface 322 contacts the outer surface of the clutch housing 11 on the axially outer side of the sensor mounting portion 117.

[0020] The connector portion 325 is provided at the bottom end 111 of the clutch housing 11, with its opening facing radially outward from the clutch device 10. The connector portion 325 is provided with connector terminals 326 and is configured to be connectable to a harness or the like (not shown).

[0021] The circuit board 33 is embedded in the circuit board holder 311 such that its mounting surface is oriented along the axial direction of the clutch device 10. The terminal 355 of the sensor unit 35 is connected to the circuit board 33. The circuit board 33 is also connected to the connector terminal 326 via wiring (not shown), and power is supplied to it.

[0022] As shown in Figures 1 to 3, the sensor unit 35, which is a Hall IC, includes a sensor element 351, a signal processing IC (not shown), a package 352, and a terminal 355. The sensor element 351 is a Hall element that detects changes in magnetic flux density and is sealed in the package 352.

[0023] The package 352 is held on the tip side of the sensor holder 312 such that the sensor element 351 is in a position to detect the magnetic flux that changes as the relative position between the movable clutch 22 and the magnet 41 changes. The terminal 355 is provided on the outside of the package 352 and is connected to the substrate 33. Figures 2 and 3 mainly illustrate the arrangement of the target movable clutch 22, sensor unit 35, and magnet 41, and the sensor housing 31 and other components are omitted. In addition, in Figure 3 and Figure 8 described later, the movable clutch 22 is shown in a simplified manner, showing only the parts related to the formation of the magnetic circuit.

[0024] As shown in Figures 3 and 4, the magnet 41 is formed in a cylindrical shape with a rectangular prism shape and a hole 411 that penetrates in the axial direction. The magnet 41 is magnetized in the axial direction; for example, in Figure 3, the left side of the paper is the north pole and the right side is the south pole, but it may be the other way around. The axis of the magnet 41 is denoted as "Ax". Figure 4 is a plan view of the magnet 41 as seen from direction IV in Figure 3.

[0025] The hole 411 is circular in plan view, and planar end faces 412 perpendicular to the axis Ax are formed on the outside of the hole 411 at both ends in the axial direction of the magnet 41. The outer shape is formed as a rectangular prism and has end faces 412, which makes it easy to position the magnet 41 when assembling it to the sensor housing 31. The inner circumference of the magnet 41 has a tapered surface 415 that widens in diameter, with a small diameter portion 413 on the end opposite the sensor portion 35 and a large diameter portion 414 on the sensor portion 35 side. The taper half-angle of the hole 411 is preferably 45°, but any angle that can secure a wider magnetic flux 0 region R0 compared to a taper angle of 0°, such as 60°, is acceptable.

[0026] In this embodiment, the sensor unit 35 detects the stroke amount of the movable clutch 22 by detecting a change in magnetic flux density between the movable clutch 22, which is made of a magnetic material, and the magnet 41, and outputs a signal corresponding to the stroke amount. In this embodiment, the sensor unit 35 is positioned between the magnet 41 and the movable clutch 22. In other words, the movable clutch 22, sensor unit 35, and magnet 41 are arranged in that order from one side in the axial direction.

[0027] In this embodiment, in order to detect the change in magnetic flux density corresponding to the stroke amount of the movable clutch 22, the sensor unit 35 is positioned in the initial state such that the sensor element 351 is at the magnetic flux zero point, which is the point where the magnetic flux density is zero. However, when assembling the sensor unit 35 and the magnet 41, the relative position of the sensor unit 35 and the magnet 41 may vary due to dimensional tolerances, etc. Also, if the sensor element 351 is not positioned at the magnetic flux zero point, the change in magnetic flux detected by the sensor element 351 in relation to the movement of the movable clutch 22 will be small, and there is a risk that detection accuracy cannot be ensured.

[0028] Therefore, in this embodiment, the hole 411 of the magnet 41 is formed in a tapered shape so that the magnetic flux 0 region R0 is widened, and the sensor unit 35 is positioned so that the sensor element 351 is within the magnetic flux 0 region R0. Here, the magnetic flux 0 region R0 is defined as the region that includes the magnetic flux 0 point and where the magnetic flux density is less than or equal to the threshold Bth. The threshold Bth is a value such that the initial magnetic flux can be considered to be 0 when the sensor element 351 is positioned in that region, and can be arbitrarily set according to the required detection accuracy, etc.

[0029] The zero magnetic flux region R0 due to the taper angle will be explained based on Figures 5 to 7. Figures 5 to 7 schematically show the magnet 41 and the zero magnetic flux region R0 in the upper part, and the relationship between the distance from the zero magnetic flux point and the magnitude of the magnetic flux density in the lower part. In the upper part, the flow of magnetic flux is shown by dashed arrows. Also, for explanatory purposes, only one side of the axial cross-section of the magnet 41 is shown. In the lower part, the zero magnetic flux point is set as the origin, the horizontal axis is the distance from the zero magnetic flux point, and the vertical axis is the magnitude of the magnetic flux density. Also, in Figures 6 and 7, the magnetic flux density when the taper angle is 0° is shown by a dashed line.

[0030] Figure 5 shows a reference configuration of a magnet 49, an example where the taper angle of the hole 491 is 0° (= half taper angle 0°). That is, the hole 491 of the magnet 49 does not widen on the side of the sensor part 35 (not shown in Figure 5). As shown in Figure 5, when the taper angle is 0°, the magnet 41 and the magnetic flux zero point are relatively close, the magnetic flux density toward the magnetic flux zero point is relatively large, and the distance over which the magnetic flux collides in the vertical direction of the paper is small. Therefore, the magnetic flux zero region R0 is a relatively narrow region.

[0031] Figure 6 shows an example of a taper half-angle of 45°, which is the inclination with respect to the axis. In the case of a taper half-angle of 45°, the magnet 41 and the magnetic flux zero point are relatively far apart due to the taper of the hole 411, the magnetic flux density toward the magnetic flux zero point is relatively small, and the distance over which the magnetic flux collides in the vertical direction of the paper is large. Therefore, the magnetic flux zero region R0 is larger compared to other taper angles.

[0032] Figure 7 shows an example with a taper half-angle of 60°. Even with a taper half-angle of 60°, it is possible to maintain the distance between the magnet 41 and the magnetic flux zero point, and the magnetic flux zero region R0 can be made larger compared to the case with a taper angle of 0°.

[0033] In other words, the inventors have found that in a cylindrical magnet 41, as a structure to suppress the influence of magnetic flux directed from the magnet 41 toward the magnetic flux zero point, the magnetic flux zero region R0 can be expanded by forming the cylindrical magnet 41 so that the inner diameter on the side facing the sensor element 351 is wider. Since the magnetic flux zero region R0 is expanded by forming the magnet 41 so that the diameter is wider on the sensor part 35 side, the accuracy of the assembly position between the sensor part 35 and the magnet 41 can be relaxed.

[0034] As described above, the sensor device 30 comprises a magnet 41 and a sensor unit 35. The cylindrical magnet 41 is magnetized in the axial direction. The sensor unit 35 is capable of detecting changes in magnetic flux due to changes in the relative position between the movable clutch 22, which is formed from a magnetic material as a target, and the magnet 41, and is positioned on one side of the magnet 41 in the axial direction. The hole 411 that penetrates the magnet 41 in the axial direction is widened such that the inner diameter at the end on the side where the sensor unit 35 is positioned is larger than the small diameter portion 413 in the axial direction. In this embodiment, the hole 411 is widened in a tapered shape. In addition, the magnet 41 is provided with a small diameter portion 413 on the end opposite to where the sensor unit 35 is positioned, and widens in one direction in the axial direction. As a result, a relatively large magnetic flux 0 region R0 can be secured, so that assembly precision can be relaxed without reducing detection accuracy. Therefore, the stroke amount can be detected accurately.

[0035] In the axial direction of the magnet 41, the movable clutch 22, the sensor unit 35, and the magnet 41 are arranged in that order from one side. This allows the sensor unit 35 to appropriately detect changes in magnetic flux due to changes in the relative position between the movable clutch 22 and the magnet 41.

[0036] The magnet 41 has a rectangular shape when viewed from above. Furthermore, the magnet 41 has flat end faces 412 formed on both sides in the axial direction. This facilitates positioning when assembling the magnet 41 into the sensor housing 31.

[0037] The sensor unit 35 is a Hall IC. This allows for the appropriate detection of changes in magnetic flux due to changes in the relative position between the movable clutch 22 and the magnet 41.

[0038] (Second Embodiment) The second embodiment is shown in Figures 8 and 9. Figure 9 is a plan view of the magnet 41 as seen from the IX direction in Figure 8. In the above embodiment, the sensor unit 35 is positioned between the movable clutch 22 and the magnet 41. That is, the movable clutch 22, the sensor unit 35, and the magnet 41 are arranged in that order from one side in the axial direction of the magnet 41.

[0039] In this embodiment, the sensor unit 35 is positioned on the opposite side of the movable clutch 22, with the magnet 41 in between. That is, from one side in the axial direction of the magnet 41, the movable clutch 22, the magnet 41, and the sensor unit 35 are arranged in that order. The inner diameter of the cylindrical magnet 41 is tapered so that the side facing the sensor unit 35 is wider. This configuration also produces the same effects as the embodiment described above.

[0040] (Third Embodiment) The third to eighth embodiments differ in the shape of the magnets, so this point will be the main focus of the explanation, and other points will be omitted. In Figures 10 to 13, it is assumed that the sensor unit 35 (not shown in Figures 10 to 13) is positioned on the left side of the page relative to the magnets 42 to 45.

[0041] The magnet 42 of the third embodiment shown in Figure 10 is formed in a cylindrical shape having a hole 421 that penetrates in the axial direction. The hole 421 has a small diameter portion 423 on the end opposite to the sensor portion 35 and a large diameter portion 424 on the side facing the sensor portion 35, and is formed in a stepped shape so that the diameter widens on the side facing the sensor portion 35. The same effect as in the above embodiment can be achieved by forming the hole 421 to widen in a stepped manner.

[0042] (Fourth Embodiment) The magnet 43 of the fourth embodiment shown in Figure 11 is formed in a cylindrical shape having a hole 431 that penetrates in the axial direction. The hole 431 has a small diameter portion 433 on the end opposite to the sensor portion 35 and a large diameter portion 434 on the side of the sensor portion 35, and is formed in an R shape with a convex axis Ax side so that the diameter increases on the side facing the sensor portion 35.

[0043] (Fifth Embodiment) The magnet 44 of the fifth embodiment shown in FIG. 12 is formed in a cylindrical shape having a hole 441 penetrating in the axial direction. The hole 441 has a small-diameter portion 443 on the end side opposite to the sensor portion 35 and a large-diameter portion 444 on the sensor portion 35 side, and is formed in an inverted R shape that is concave on the axis Ax side so that the side facing the sensor portion 35 expands in diameter. Forming the hole in an R shape or an inverted R shape also exhibits the same effects as in the above embodiment.

[0044] (Sixth Embodiment) The magnet 45 of the sixth embodiment shown in FIG. 13 is formed in a cylindrical shape having a hole 451 penetrating in the axial direction. The hole 451 has a small-diameter portion 453 in the intermediate portion in the axial direction, and tapered surfaces 456 and 457 that expand in diameter so that both end sides in the axial direction become large-diameter portions 454 and 455. In this embodiment, the tapered surfaces 456 and 457 are formed symmetrically with respect to a plane that bisects the magnet 45 in the axial direction. The diameter-expanding shape is not limited to a tapered shape, and may be the shape of the third to fifth embodiments. In the magnet 45, by providing a small-diameter portion 453 in the intermediate portion in the axial direction and having a shape that expands in diameter in both axial directions, it can be assembled to the sensor housing 31 (not shown in FIG. 13) without directionality in the axial direction, and the assembly property is improved. Also, the same effects as in the above embodiment are exhibited.

[0045] (Seventh Embodiment) FIGS. 14 and 15 are diagrams corresponding to FIG. 4 of the first embodiment, and the magnet 46 of the seventh embodiment shown in FIG. 14 has an outer shape formed in a circular shape in plan view and is formed in a cylindrical shape having a hole 461 penetrating in the axial direction. By making the magnet 46 cylindrical, the magnet 46 can be assembled to the sensor housing 31 (not shown in FIG. 14) regardless of the circumferential direction.

[0046] (8th Embodiment) The magnet 47 of the 8th embodiment shown in Fig. 15 has an outer shape formed in a circular shape in plan view and has a hole 471 penetrating in the axial direction. A part of the outer peripheral wall of the magnet 47 is cut away, and two side flat portions 472 and 473 are formed. The two side flat portions 472 and 473 are formed along the axial direction and are formed in parallel on both sides with the hole 471 interposed therebetween. This makes it easy to position the magnet 47 when assembling it to the sensor housing 31 (not shown in Fig. 15).

[0047] In the 7th and 8th embodiments, the holes 461 and 471 are formed in a tapered shape as in the 1st embodiment, but the shape of the holes 461 and 471 may be any of the 3rd to 6th embodiments. Even with this configuration, the same effects as those of the above embodiments can be obtained.

[0048] (Other Embodiments) In the above embodiment, the hole of the magnet is formed in a circular shape in plan view. In other embodiments, the hole only needs to have a larger diameter on the sensor part side, and may have a shape different from the circular shape in plan view, such as an elliptical shape in plan view.

[0049] In the above embodiment, the sensor part is a Hall IC. In other embodiments, the sensor part is not limited to a Hall IC, and any device capable of detecting a change in magnetic flux density may be used. Also, in the above embodiment, the target is a movable clutch, and the sensor device is a stroke sensor for detecting the clutch stroke. In other embodiments, the target only needs to be something whose magnetic flux changes according to a change in the relative position with the magnet, and the sensor device may be other than a stroke sensor. Also, the configuration of the clutch device and the like may be different from that of the above embodiment.

[0050] (Disclosure of Technical Ideas) This specification discloses several technical ideas as described in the following paragraphs. Some paragraphs may be written in a multiple dependent form, where subsequent paragraphs optionally refer to preceding paragraphs. Furthermore, some paragraphs may be written in a multiple dependent form, where they refer to other multiple dependent forms. These paragraphs written in multiple dependent forms define several technical ideas.

[0051] (Technical Concept 1) A sensor device comprising: cylindrical magnets (41-47) magnetized in the axial direction; a sensor unit (35) positioned on one side of the magnet in the axial direction, capable of detecting changes in magnetic flux due to a change in the relative position between a target (22) formed of a magnetic material and the magnet, wherein the holes (411, 421, 431, 441, 451, 461, 471) penetrating the magnet in the axial direction are widened such that the inner diameter of the end on the side where the sensor unit is positioned is larger than the small diameter portion (413, 423, 433, 443, 453) in the axial direction. (Technical Concept 2) The sensor device according to Technical Concept 1, wherein the holes (411, 451) are widened in a tapered shape. (Technical Concept 3) The sensor device according to Technical Concept 1, wherein the hole (421) is widened in a stepped shape. (Technical Idea 4) The sensor device according to Technical Idea 1, wherein the hole (431) is R-shaped and has an expanded diameter. (Technical Idea 5) The sensor device according to Technical Idea 1, wherein the hole (441) is R-shaped and has an expanded diameter. (Technical Idea 6) The sensor device according to any one of Technical Ideas 1 to 5, wherein the magnets (41 to 44) are provided with the small diameter portions (413, 423, 433, 443) on the end opposite to where the sensor portion is located, and are expanded in one direction in the axial direction. (Technical Idea 7) The sensor device according to any one of Technical Ideas 1 to 5, wherein the magnet (45) is provided with the small diameter portion (453) in the middle part in the axial direction, and is expanded in both directions in the axial direction. (Technical Idea 8) The sensor device according to any one of Technical Ideas 1 to 7, wherein in the axial direction of the magnet, the target, the sensor portion, and the magnet are arranged in that order from one side. (Technical Idea 9) A sensor device according to any one of Technical Ideas 1 to 7, wherein the target, the magnet, and the sensor unit are arranged in that order from one side in the axial direction of the magnet. (Technical Idea 10) A sensor device according to any one of Technical Ideas 1 to 9, wherein the external shape of the magnet is rectangular in plan view. (Technical Idea 11) A sensor device according to any one of Technical Ideas 1 to 9, wherein the external shape of the magnet is circular in plan view.(Technical Idea 12) The sensor device according to any one of Technical Ideas 1 to 9, wherein the outer shape of the magnet is circular in plan view and has lateral planar portions (472, 473) formed parallel to the axial direction. (Technical Idea 13) The sensor device according to any one of Technical Ideas 1 to 12, wherein the magnet has end faces (412) formed planarly on both sides in the axial direction. (Technical Idea 14) The sensor device according to any one of Technical Ideas 1 to 13, wherein the sensor part is a Hall IC.

[0052] The present disclosure is not limited in any way to the embodiments described above, and can be implemented in various forms without departing from its spirit.

[0053] This disclosure is described in accordance with embodiments. However, this disclosure is not limited to such embodiments and structures. This disclosure also includes various modifications and variations within the scope of equivalents. Furthermore, various combinations and forms, as well as other combinations and forms that include only one, more, or fewer of those elements, fall within the scope and idea of ​​this disclosure.

Claims

1. A sensor device comprising: cylindrical magnets (41-47) magnetized in the axial direction; a sensor unit (35) positioned on one side of the magnet in the axial direction, capable of detecting changes in magnetic flux due to changes in the relative position between a target (22) formed of a magnetic material and the magnet; wherein the holes (411, 421, 431, 441, 451, 461, 471) that penetrate the magnet in the axial direction are enlarged such that the inner diameter of the end on the side where the sensor unit is positioned is larger than the small diameter portion (413, 423, 433, 443, 453) in the axial direction.

2. The sensor device according to claim 1, wherein the holes (411, 451) are tapered and widen in diameter.

3. The sensor device according to claim 1, wherein the hole (421) is stepped and widens in diameter.

4. The sensor device according to claim 1, wherein the hole (431) is R-shaped and has an enlarged diameter.

5. The sensor device according to claim 1, wherein the hole (441) is enlarged in an inverted R shape.

6. The sensor device according to any one of claims 1 to 5, wherein the magnets (41 to 44) are provided with the small-diameter portions (413, 423, 433, 443) on the end opposite to where the sensor portion is located, and the diameter is increased in one direction in the axial direction.

7. The sensor device according to any one of claims 1 to 5, wherein the magnet (45) is provided with the small diameter portion (453) in the axial middle portion and is widened in both axial directions.

8. The sensor device according to any one of claims 1 to 5, wherein the target, the sensor unit, and the magnet are arranged in the order of the target, the sensor unit, and the magnet from one side in the axial direction of the magnet.

9. The sensor device according to any one of claims 1 to 5, wherein the target, the magnet, and the sensor unit are arranged in that order from one side in the axial direction of the magnet.

10. The sensor device according to any one of claims 1 to 5, wherein the external shape of the magnet is rectangular in plan view.

11. The sensor device according to any one of claims 1 to 5, wherein the external shape of the magnet is circular in plan view.

12. The sensor device according to any one of claims 1 to 5, wherein the outer shape of the magnet is circular in plan view and has lateral planar portions (472, 473) formed parallel to the axial direction.

13. The sensor device according to any one of claims 1 to 5, wherein the magnet has end faces (412) formed in a planar manner on both sides in the axial direction.

14. The sensor device according to any one of claims 1 to 5, wherein the sensor unit is a Hall IC.

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