JP5148418B2 - Magnetic rotation detector - Google Patents

Description

  The present invention relates to a magnetic rotation detection device for detecting an angular position, a rotation speed, and the like of a rotating body.

Among the rotation detectors, there are two types of non-contact type: optical type and magnetic type. The magnetic type rotation detection device has more dust and moisture than the optical type rotation detection device. There is an advantage that it can be used in an environment or in a liquid. That is, a magnetic rotation detection device generally includes a magnet body in which a magnetic pole pair composed of an S pole and an N pole is formed, and a magnetosensitive element that detects an angular position and a rotation speed when the magnet body rotates. Even if dust or moisture adheres to the magnet body, the sensitivity does not decrease. In such a magnetic rotation detection device, for example, a plurality of magnetic pole pairs composed of an S pole and an N pole are formed on the outer peripheral surface of the magnet body, and a magnetosensitive element is disposed at a position facing the outer peripheral surface of the magnet body. (See Patent Document 1).
JP 2008-151774 A

  However, in the device described in Patent Document 1, since the number of magnetization poles is the output pulse (resolution) as it is, when the resolution is increased, the magnet body and the magnetosensitive element are arranged close to, for example, about several tens of μm. There is a need to. Therefore, the conventional magnetic rotation detecting device cannot protect the magnetic sensitive element from dust, moisture, etc., and has a problem of low environmental resistance.

  In view of the above problems, an object of the present invention is to provide a magnetic rotation detection device that can protect a magnetosensitive element from dust, moisture, and the like without reducing resolution.

In order to solve the above-mentioned problem, in the present invention, a magnetic rotation having a magnetic pole pair composed of an S pole and an N pole and having a magnet body provided on the rotating body side and a magnetosensitive element facing the magnet body. The detection device further includes a case in which the magnetosensitive element is housed inside, and the case includes a first case body including a partition wall interposed between the magnet body and the magnetosensitive element; A second case body that covers the magnetic sensing element together with the first case body, wherein the first case body and the second case body are joined so as to surround the magnetic sensing element, and A sealing agent is applied to a joint portion between the one case body and the second case body, the magnet body and the magnetosensitive element are opposed to each other in the rotation center axis direction of the rotating body, and the partition wall portion is , The bottom of the recess recessed toward the side where the magnet body is located, The magnetosensitive element is disposed in a portion, the magnetosensitive element is mounted on a substrate, the substrate is disposed to overlap a substrate receiving portion formed around the concave portion, and the magnetosensitive element is A gap is provided between the bottom of the recess and the bottom .

  In the present invention, the magnet body preferably includes a pair of S poles and N poles.

  In the present invention, the number of magnetic pole pairs formed in the magnet body is reduced. Instead, for example, interpolation processing is performed on the signal obtained by the magnetosensitive element to obtain a zero cross point to ensure resolution. To do. According to such a configuration, the number of magnetic pole pairs formed on the magnet body is reduced to a minimum of one pair, so that sufficient sensitivity can be obtained even if the magnet body and the magnetosensitive element are somewhat separated. Therefore, a partition wall can be provided between the magnet body and the magnetosensitive element. In the present invention, the first case body having the partition wall and the second case body cover the magnetosensitive element, and surround the first case body and the second case body around the magnetosensitive element. And apply a sealant to the joint. For this reason, it is possible to reliably protect the magnetosensitive element and further the substrate on which the magnetosensitive element is mounted from dust and moisture.

Further, in the present invention, the magnet member and said magnetic sensing element, since faces with rotation axis line direction of the rotating body, it is possible to obtain a small sinusoidal signal waveform distortion through the magnetic sensitive element .

Further, in the present invention, the partition wall portion, said a bottom portion of the magnet body recess recessed toward the side that is located, that has the sensing element is disposed in the recess. Although the thinner the entire plate-like portion interposed between the magnet body and the magnetic sensing element in the first case body is limited, the concave portion is provided on the plate-like portion, by utilizing the bottom of such recess as a partition portion For example, even when a partition wall is provided between the magnetic sensing element and the magnet body, the magnetic sensing element and the magnet body can be brought close to each other. Therefore, the S / N ratio of the output from the magnetosensitive element is improved. That is, the stronger the magnetic field, the more saturated it can be used, so the sine wave output becomes closer to a sine wave.

In addition, in the present invention , the magnetosensitive element is mounted on a substrate, and the substrate is disposed so as to overlap a substrate receiving portion formed around the recess, and the magnetosensitive element is disposed at the bottom of the recess. that are separated by a gap between the. The magnetosensitive element has a drawback that it is weak against stress. However, when such a configuration is adopted, the magnetosensitive element can be disposed in a non-contact state on the partition wall (the bottom of the recess). Therefore, even when the magnetosensitive element and the magnet body are brought close to each other, no stress is applied to the magnetosensitive element, so that the magnetosensitive element exhibits high sensitivity.

In the present invention, the first case body includes a first plate-like portion provided with the partition wall portion, and a first side plate portion standing on an outer peripheral edge of the first plate-like portion, and the second case The body includes a second plate-shaped portion facing the first plate-shaped portion, and a second side plate portion standing up toward the first side plate portion at an outer peripheral edge of the second plate-shaped portion, the outer peripheral side surface of the cases, one of the first case body and the second case body, it is preferable that the side plate portion of one of the case body overlaps the outer surface of the side plate portion of the other of the case body. If comprised in this way, the penetration | invasion of the dust from the side case part of a 1st case body and a 2nd case body and a water | moisture content can be blocked | prevented effectively.

  In the present invention, the side plate portion of the other case body includes a step portion that forms a first groove portion that opens toward an outer peripheral side between the side plate portion and the tip edge of the side plate portion of the one case body, It is preferable that the sealing agent is applied in the groove. That is, the inner side plate portion includes a step portion that forms a first groove portion that opens toward the outer peripheral side between the front edge of the outer side plate portion, and the sealing agent is applied in the first groove portion. Preferably it is. If comprised in this way, the penetration | invasion of the dust from the side plate part of a 1st case body and a 2nd case body and a water | moisture content can be prevented reliably.

  In the present invention, the other case body is formed with a tubular portion through which the shaft portion of the fastening member passes continuously from the side plate portion of the other case body, and the one case body avoids the tubular portion. A notch is formed, and a second groove portion is formed between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the notch, and communicates with the first groove portion and opens toward the rotation center axis direction. It is preferable that the sealing agent is applied also in the second groove portion. If comprised in this way, the structure which apply | coated the sealing agent in the continuous groove part also including the part in which the cylinder part is formed is employable between the 1st case body and the 2nd case body. Therefore, intrusion of dust and moisture from the side plate portions of the first case body and the second case body can be effectively prevented.

In the present invention, the number of magnetic pole pairs formed in the magnet body is reduced. Instead, for example, interpolation processing is performed on the signal obtained by the magnetosensitive element to obtain a zero cross point to ensure resolution. To do. According to such a configuration, the number of magnetic pole pairs formed on the magnet body is reduced to a minimum of one pair, so that sufficient sensitivity can be obtained even if the magnet body and the magnetosensitive element are somewhat separated. Therefore, a partition wall can be provided between the magnet body and the magnetosensitive element. In the present invention, the first case body having the partition wall and the second case body cover the magnetosensitive element, and surround the first case body and the second case body around the magnetosensitive element. And apply a sealant to the joint. For this reason, the magnetosensitive element can be reliably protected from dust and moisture. Furthermore, in the present invention, since the magnet body and the magnetosensitive element face each other in the direction of the rotation center axis of the rotating body, a sine wave signal with little waveform distortion can be obtained via the magnetosensitive element. . In the present invention, the partition wall is a bottom of a recess recessed toward the side where the magnet body is located, and since the magnetosensitive element is disposed in the recess, the magnetosensitive element and the magnet body Even when a partition wall is provided between the magnetic sensing element and the magnet body, the magnetic sensing element and the magnet body can be brought close to each other. Therefore, the S / N ratio of the output from the magnetosensitive element is improved. That is, the stronger the magnetic field, the more saturated it can be used, so the sine wave output becomes closer to a sine wave. In addition, in the present invention, the magnetosensitive element is mounted on a substrate, and the substrate is disposed so as to overlap a substrate receiving portion formed around the recess, and the magnetosensitive element is disposed at the bottom of the recess. Therefore, the magnetosensitive element can be arranged in a non-contact state on the partition wall (bottom part of the recess). Therefore, even when the magnetosensitive element and the magnet body are brought close to each other, no stress is applied to the magnetosensitive element, so that the magnetosensitive element exhibits high sensitivity.

  In the following, the present invention will be described with reference to the drawings, a magnetic rotation detection device and a method for manufacturing the same.

(Overall configuration of magnetic rotation detector)
1A and 1B are an external view and an exploded perspective view of a magnetic rotation detector to which the present invention is applied. 2A and 2B are a cross-sectional view schematically showing a configuration of a main part of a magnetic rotation detection apparatus to which the present invention is applied, and an explanatory view showing the detection principle. 3A and 3B are a perspective view of a main part of a magnetic rotation detecting device to which the present invention is applied, and a perspective view of a state where a magnet body and a rotating circuit unit are separated from each other. FIG. 4 and FIG. 5 are explanatory views as seen from the side of the first case body and an explanatory view as seen from the side of the second case body, in which the rotary circuit unit of the magnetic rotation detector to which the present invention is applied is disassembled. .

  A magnetic rotation detection device 10 shown in FIGS. 1A, 1B, and 2A is a device that magnetically detects the rotation position, rotation direction, and rotation speed of a rotating body. The rotation of the rotating shaft 22 of the motor 2 is detected. In this embodiment, the rotation of the rotating shaft 22 is detected based on the motor case 27. Here, the magnetic rotation detection device 10 is configured integrally with the motor 2 and constitutes the motor 1 with an encoder. The rotating shaft 22 corresponds to the opposite end portion of the output shaft 28 of the motor 2.

  The magnetic rotation detection device 10 includes a magnet body 20 fixed to the rotation shaft 22 of the motor 2, and a circuit unit 30 in which a substrate 40 on which a magnetosensitive element 42 and a semiconductor IC 46 are mounted is incorporated in a case 33. The magnetosensitive element 42 faces the magnet body 20 in the direction of the rotation center axis L of the rotation shaft 22. In this embodiment, the magnetosensitive element 42 is composed of an MR element, and the magnetoresistive film 421 is arranged in a predetermined pattern.

  The magnet body 20 includes a metal magnet holder 21 fixed to the rotating shaft 22 and a disk-shaped permanent magnet 25, and the permanent magnet 25 has a flange portion 213 that expands at the tip of the magnet holder 21. It is fixed to the upper surface of the substrate with an adhesive. Here, as shown in FIGS. 1B and 2B, the permanent magnet 25 has a pair of S and N poles magnetized in the circumferential direction on the surface facing the magnetosensitive element 42.

  As shown in FIG. 2B, the rotation detection circuit constituted by the semiconductor IC 46 of the circuit unit 30 is output from a pair of amplifier circuits 481 that output signals from the magnetosensitive element 42 and these amplifier circuits 481. An arithmetic circuit 482 (interpolation circuit) that obtains a zero cross point by performing interpolation processing or the like on the sine wave signals sin and cos and an output interface 483 are provided. This is done via a female connector 48 mounted on the cable.

(Configuration of circuit unit)
1 (a), (b), FIG. 2 (a), FIG. 3 (a), (b), FIG. 4, and FIG. The 30 case 33 includes a resin-made first case body 31 positioned on the magnet body 20 side with respect to the substrate 40 and a resin-made second case positioned on the opposite side of the substrate 40 from the magnet body 20 side. The first case body 31 constitutes a partition member that is interposed between the magnet body 20 and the magnetic sensitive element 42.

  The first case body 31 includes a substantially rectangular plate-shaped portion 315 and three side plate portions 316 that stand up toward the second case body 32 at positions corresponding to the three sides of the plate-shaped portion 315. The concave portion 315 is formed with a circular recess 318 that is recessed from the substrate receiving portion 315a side toward the outer surface side where the magnet body 20 is located. The first case body 31 is a resin molded product, and the bottom 318 a of the recess 318 is thinner than the portion of the plate-like portion 315 other than the recess 318. On the inner surface of the plate-like portion 315, a portion surrounding the recess 318 is a substrate receiving portion 315a to which the substrate 40 is fixed. The substrate 40 is fixed in a flat state to the substrate receiving portion 315a.

  The substrate 40 has a magnetosensitive element 42 mounted at the approximate center of the surface facing the magnet body 20 (see FIGS. 4 and 5). A semiconductor IC 46 and a female connector 48 constituting a rotation detection circuit are mounted on the back surface side of the substrate 40, and the female connector 48 is in the vicinity of a side of the plate-like portion 315 where the side plate portion 316 is not formed. Has been implemented.

  In the first case 31 configured as described above, when the substrate 40 is stacked on the substrate receiving portion 315a in a flat state, the magnetosensitive element 42 is disposed in the recess 318, and the bottom 318a of the recess 318 is connected to the magnetosensitive element 42. It functions as a partition part interposed between the magnet bodies 20. In this state, the magnetosensitive element 42 is not in contact with the bottom 318a of the recess 318 (see FIG. 2A).

  In the first case body 31, a circular annular groove 319 is formed on the outer surface side of the plate-like portion 315 where the magnet body 20 is located so as to surround the bottom portion 318 a of the recess 318 as shown in FIG. The end of the annular ring 15 is fitted in the annular groove 319 and fixed by a method such as adhesion. Only the end of the ring 15 opposite to the side where the magnet body 20 is located (the side where the magnetic sensing element 42 is located) is fitted in the annular groove 319, and the opposite end is the bottom of the recess 318. It protrudes to the side where the magnet body 20 is located from 318a (see FIG. 3). Moreover, the inner diameter of the ring 15 is slightly larger than the outer diameter of the magnet body 20. The permanent magnet 25 and the flange portion 213 of the magnet body 20 are located inside the ring 15 configured as described above, and in this state, the ring 15 is disposed on the outer peripheral surface of the magnet body 20 in the radial direction outside via a gap. Opposite states.

  The ring 15 is made of a magnetic material and has a function of performing a magnetic shield on the magnet body 20. Further, in the magnetic rotation detection device 10 of the present embodiment, the centers of the magnet body 20 and the magnetosensitive element 42 are aligned with the ring 15 as a reference, as will be described later. For this reason, the center of the magnetosensitive element 42 is located on the center axis of the ring 15, and the center of the magnet body 20 is located on the center axis of the ring 15.

  The second case body 32 has a substantially rectangular plate-like portion 325 facing the plate-like portion 315 of the first case body 31 and a side plate portion 316 of the first case body 31 at a position corresponding to three sides of the plate-like portion 325. Three side plate portions 326 that stand up toward each other, and in the first case body 31 and the second case body 32, the sides on which the side plate portions 316 and 326 are formed coincide with each other. For this reason, when the second case body 32 is put on the first case body 31, the side plate portions 316 and 326 overlap each other, but the position corresponding to one side of the four sides opens to the outside. It becomes. Therefore, since the female connector 48 is exposed to the outside, the male connector 49 can be coupled to the female connector 48. In the second case body 32, the plate-like portion 325 has a protrusion 325c that presses the substrate 40 against the substrate receiving portion 315a.

(Waterproof structure for the magnetic sensitive element 42)
When the first case body 31 and the second case body 32 thus configured overlap, the side plate portion 316 of the first case body 31 covers the outer surface of the side plate portion 326 of the second case body 32. When the side plate portions 316 and 326 are joined to each other using the overlap, the side plate portion 326 of the second case body 32 is directed to the first case body 31 from the inner peripheral side of the thick portion 326c formed of the root portion. The thin portion 326d extends, and the width dimension of the thin portion 326d is slightly wider than the portion overlapping the side plate portion 316 of the first case body 31. Therefore, when the first case body 31 and the second case body 32 are overlapped, the thick portion 326c and the thin wall portion 326 are interposed between the side plate portion 316 of the first case body 31 and the side plate portion 326 of the second case body 32. A first groove portion 36 is formed between the step portion 326 a with the portion 326 d and the leading edge of the side plate portion 316 of the first case body 31. The first groove portion 36 is formed in a continuous state over all of the three side plate portions 316 and 326 of the first case body 31 and the second case body 32. Therefore, in this embodiment, the sealing agent 35 is applied to the entire first groove portion 36 formed over the three side plate portions 316 and 326 and then solidified to prevent water from entering the case 33. In addition, in the part in which the female connector 48 is located, the space between the first case body 31 and the second case body 32 is greatly opened, but before or after the male connector 49 is coupled to the female connector 48, If the sealing agent 35 is applied and solidified on such a portion, water can be prevented from entering the case 33. Although there is no limitation about the material of the sealing agent 35, a silicone resin etc. can be used.

  A small projection 326e (see FIG. 4) for fixing is formed on the side plate portion 326 of the second case body 32, while the small projection 326e is fitted on the plate-like portion 315 of the first case body 31. A small hole 315e (see FIG. 5) is formed at the bottom. Therefore, when the small protrusion 326e of the second case body 32 is fitted into the small hole 315e of the first case body 31, the first case body 31 and the second case body 32 can be coupled.

(Positioning structure using spacers)
In the magnetic rotation detection device 10 configured as described above, the case 33 of the circuit unit 30 is fixed to the motor case 27 via the spacer 50 having a rectangular parallelepiped shape. That is, the spacer 50 is fixed to the end surface of the motor case 27 by the two bolts 59 as the fastening members at the diagonal position, and the case 33 is fixed to the end surface of the spacer 50 by the two bolts 39 at the diagonal position. Has been. In performing such fastening, if a cylindrical portion through which the bolt 59 is passed is formed in both the first case body 31 and the second case body 32, the sealing performance at the joint portion is lowered. Therefore, in this embodiment, of the first case body 31 and the second case body 32, only the second case body 32 is formed with two cylindrical portions 328 through which the shaft portion of the bolt 39 passes continuously from the side plate portion 326. ing. Further, in this embodiment, for the purpose of preventing water from entering the case 33 from around the cylindrical portion 328, the plate-like portion 315 of the first case body 31 has a circular shape so as to avoid the cylindrical portion 328. An arcuate notch 317 is formed. When the first case body 31 and the second case body 32 overlap, the magnet body 20 is located between the outer peripheral surface of the cylindrical portion 328 and the inner peripheral surface of the notch 317 in the rotation center axis L direction. A second groove portion 37 is formed that opens toward the positioned side. Therefore, in this embodiment, when the sealing agent 35 is applied to the first groove portion 36, the sealing agent 35 is also applied to the second groove portion 37. Here, the 1st groove part 36 and the 2nd groove part 37 comprise the groove part which was connected and continued. For this reason, in the case 33, the entire circumference except for the portion where the female connector 48 is disposed is sealed with the sealing agent 35.

  Although the outer shape of the spacer 50 used in this embodiment is a rectangular parallelepiped shape, a circular through hole 51 opened in the direction of the rotation center axis L of the rotating shaft 22 is formed, and the magnet body 20 is placed in the through hole 51. To position. The inner diameter dimension of the through hole 51 is larger than the outer diameter dimension of the flange portion 213 of the magnet body 20, and an annular gap is formed between the inner peripheral surface of the through hole 51 and the outer peripheral surface of the magnet body 20. Is formed. The end of the ring 15 is inserted into the gap. The outer diameter of the ring 15 is substantially the same as the inner diameter of the through hole 51, and the ring 15 is in a state of being fitted in the through hole 51. In this state, a gap is interposed between the outer peripheral surface of the flange portion 213 of the magnet body 20 and the inner peripheral surface of the ring 15. In this way, the ring 15 is positioned in the radial direction with respect to the spacer 50.

(Manufacturing method of magnetic rotation detector 10)
FIG. 6 is an explanatory diagram showing a method for manufacturing the magnetic rotation detection device 10 of the present embodiment. In order to manufacture the magnetic rotation detection device 10 of this embodiment, first, the ring 15 is fixed to the first case body 31 before being coupled to the second case body 32 in the first alignment step, and the ring 15 After aligning the ring 15 and the magnetosensitive element 42 so that the center of the magnetosensitive element 42 is positioned on the center axis of the substrate 40, the substrate 40 is fixed to the first case body 31. More specifically, for example, each of the two robot hands holds the ring 15 and the substrate 40, and after adjusting the positions thereof, the substrate 40 is fixed to the first case body 31. At this time, the substrate 40 is temporarily bonded to the first case body 31 using a quick-drying adhesive such as UV adhesive, and then the substrate 40 is bonded to the first case body 31 using an adhesive made of a thermosetting resin. Glue. Thereafter, the first case body 31 is covered with the second case body 32, and the small groove 315e of the second case body 32 is fitted into the small hole 315e of the first case body 31 and fixed. After the sealing agent 35 is applied to the groove portion 37, it is solidified and the case 33 is sealed.

  Next, in the second alignment step, the ring 15 and the magnet body 20 are aligned so that the center of the magnet body 20 is positioned on the center axis of the ring 15. First, as shown in FIGS. 6A and 6E, after the rotating shaft 22 of the motor 2 is fitted in the hole formed in the end portion of the shaft portion 211 of the magnet holder 21, the shaft portion 211 A set screw 219 is fitted into a hole formed in the peripheral surface from the side to restrict movement in the rotation direction, and the magnet body 20 is fixed to the rotating shaft 22. Next, as shown in FIGS. 6B and 6E, the spacer 50 is disposed on the end surface of the motor case 27 so that the magnet body 20 enters the through hole 51 of the spacer 50 (first operation).

  Next, as shown in FIGS. 6C and 6E, the cylindrical portion 61 of the jig 60 is inserted between the inner wall of the through hole 51 of the spacer 50 and the outer peripheral surface of the magnet body 20, and the jig 60 is interposed therebetween. The spacer 50 and the magnet body 20 are aligned (second operation). That is, the jig 60 includes a cylindrical portion 61 having a constant thickness in the circumferential direction, and the inner diameter of the cylindrical portion 61 is substantially the same as the outer dimensions of the flange portion 213 of the magnet body 20 and the permanent magnet 25. The inner diameter of the through hole 51 of the spacer 50 is substantially the same. Therefore, in the state shown in FIGS. 6C and 6E, the through hole 51 of the spacer 50, the flange portion 213 of the magnet body 20, and the permanent magnet 25 are arranged concentrically.

  Next, as shown in FIG. 6D, after fixing the spacer 50 to the motor case 27 with the bolt 59, the jig 60 is removed (third operation).

  After that, after inserting the ring 15 of the circuit unit 30 assembled in the state shown in FIG. 3B into the through hole 51 of the spacer 50, the case 33 of the circuit unit 30 is fixed to the spacer 50 with the bolt 39. (Fourth operation). As a result, the magnetic rotation detection device 10 is assembled in a state where the ring 15 and the magnet body 20 are aligned so that the center of the magnet body 20 is positioned on the center axis of the ring 15.

(Main effects of this form)
As described above, in the magnetic rotation detection device 10 of this embodiment, the number of magnetic pole pairs formed in the magnet body 20 is reduced, and instead, for example, interpolation processing is performed on the signal obtained by the magnetosensitive element 42. To ensure resolution by performing arithmetic processing such as finding the zero cross point. According to such a configuration, the number of magnetic pole pairs formed on the magnet body 20 is reduced to a minimum of one pair, so that sufficient sensitivity can be obtained even if the magnet body 20 and the magnetosensitive element 42 are somewhat separated. Moreover, since the magnet body 20 and the magnetosensitive element 42 are opposed to each other in the direction of the rotation center axis L of the rotary shaft 22, even if the magnet body 20 and the magnetosensitive element 42 are somewhat separated from each other, the magnetosensitive element A sine wave signal with little waveform distortion can be obtained via the line 42. Therefore, a partition wall (the bottom 318 a of the recess 318 of the first case body 31) can be provided between the magnet body 20 and the magnetic sensing element 42. In the present invention, the first case body 31 and the second case body 32 cover the magnetosensitive element 42, and the first case body 31 and the second case body 32 are surrounded around the magnetosensitive element 42. The sealing agent 35 is applied to the joint portion. For this reason, case 33 can be made into a waterproof structure, and magnetic sensing element 42 can be reliably protected from water.

  The partition wall is a bottom 318a of a recess 318 that is recessed toward the side where the magnet body 20 is located in the plate-like portion, and the magnetosensitive element 42 is disposed in the recess 318. For this reason, although there is a limit in making the whole plate-shaped part 315 thin in the 1st case body 31, the magnetosensitive element 42 and the magnet body 20 can be made to approach. The substrate 40 on which the magnetosensitive element 42 is mounted is disposed so as to overlap the substrate receiving portion 315a formed around the recess 318 in the plate-like portion 315, and the magnetosensitive element 42 is connected to the bottom 318a of the recess 318. There is a gap between them. For this reason, the magnetic sensitive element 42 can be arrange | positioned in a non-contact state to the partition (bottom part 318a of the recessed part 318). Therefore, even when the magnetosensitive element 42 and the magnet body 20 are brought close to each other, no extra stress is applied to the magnetosensitive element 42, so that the magnetosensitive element 42 exhibits high sensitivity.

  Further, since the space between the first case body 31 and the second case body 32 is sealed with the sealing agent 35 applied between them, the side plate portions 316 of the first case body 31 and the second case body 32 are used. 326 can be effectively prevented from entering water. Moreover, the sealing agent 35 is applied to the inside of the first groove portion 36 and the second groove portion 37. Moreover, the 1st groove part 36 and the 2nd groove part 37 comprise the groove part which was connected and continued. For this reason, in the case 33, the entire circumference except for the portion where the female connector 48 is disposed is sealed with the sealing agent 35, so that the entry of water can be reliably prevented.

  Further, in the magnetic rotation detection device 10 of the present embodiment, the ring 15 is fixed to the plate-like portion 315 of the first case body 31 interposed as a partition member between the magnet body 20 and the magnetic sensing element 42, and the ring 15 The positions of the magnet body 20 and the magnetosensitive element 42 are determined based on the above. That is, in the method of manufacturing the magnetic rotation detection device 10, the position of the magnetic sensing element 42 on the first case 33 is determined with reference to the ring 15, and the spacer 15 and the jig 60 are used to sense the ring 15 as a reference. The positions of the magnetic element 42 and the magnet body 20 are determined. Therefore, since the positional accuracy between the magnetosensitive element 42 and the magnet body 20 is high, the magnetosensitive element 42 can detect the rotation of the magnet body 20 with high sensitivity.

  Further, when the ring 15 is fixed to the first case body 31, the ring 15 is fitted in the annular groove 319 surrounding the recess 318, so that the ring 15 is securely fixed to a predetermined position of the first case body 31. can do.

  Further, since the ring 15 functions as a magnetic shield part for the magnet body 20, it is possible to perform magnetic shielding without using a dedicated shield member, and the magnetosensitive element 42 rotates the magnet body 20 with high sensitivity. Can be detected.

[Other embodiments]
In the above embodiment, since the side plate portion 316 of the first case body 31 overlaps the outer surface of the side plate portion 326 of the second case body 32, the step portion 326a is provided on the side plate portion 326 of the second case body 32 to provide the first groove portion. 36, when the side plate portion 326 of the second case body 32 overlaps the outer surface of the side plate portion 316 of the first case body 31, a step portion is provided on the side plate portion 316 of the first case body 31 to provide the first groove portion 36. May be formed.

  In the above embodiment, the rotating body is the rotating shaft 22 of the motor 2 and the stationary body is the motor case 27. However, the magnet body 20 is formed on the rotating body of another rotating mechanism, and the stationary body supports the rotating body. The circuit unit 30 may be attached to the body via the spacer 50. Note that “stationary” in the stationary body means to confront “rotation” of the rotating shaft 22, and includes the case where the stationary body itself moves together with the rotating shaft 22. Further, the stationary body may be a member other than the motor case 27, for example, a part of a device on which the motor 2 is mounted.

  In the above embodiment, the permanent magnet 25 is formed with a pair of S poles and N poles, but the waterproof structure of the present invention may be applied when a plurality of pairs of S poles and N poles are formed.

  In the above embodiment, the magnet body 20 and the magnetosensitive element 42 are opposed in the direction of the rotation center axis L. However, when the magnet body 20 and the magnetosensitive element 42 are opposed in the radial direction, the waterproof structure of the present invention. May be applied.

  In the above-described embodiment, the positioning using the ring 15 is applied in the case of two case bodies. However, for the positioning using the ring 15, the substrate 40 on which the magnetosensitive element 42 is mounted is made of a resin having a small stress, For example, the present invention may be applied to a structure in which a short glass fiber is integrally molded with a BMC resin mixed with a reinforcing agent or a filler in a thermosetting resin mainly composed of an unsaturated polyester resin. In this case, the partition member is formed by the portion covering the magnetic sensitive element 42 in the mold resin.

(A), (b) is the external view of the magnetic-type rotation detection apparatus to which this invention is applied, and its disassembled perspective view. (A), (b) is sectional drawing which shows typically the structure of the principal part of the magnetic-type rotation detection apparatus to which this invention is applied, and explanatory drawing which shows the detection principle. (A), (b) is the perspective view of the principal part of the magnetic rotation detection apparatus to which this invention is applied, and the perspective view of the state which isolate | separated the magnet body and the rotation circuit unit. It is explanatory drawing which looked at a mode that the rotation circuit unit of the magnetic type rotation detection apparatus to which this invention was applied was decomposed | disassembled from the 1st case body side. It is explanatory drawing which looked at a mode that the rotation circuit unit of the magnetic type rotation detection apparatus to which this invention was applied was decomposed | disassembled from the 2nd case body side. It is explanatory drawing which shows the manufacturing method of the magnetic-type rotation detection apparatus to which this invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor with encoder 2 Motor 10 Magnetic rotation detector 15 Ring 20 Magnet body 22 Rotating shaft (rotating body) of motor
27 Motor case (stationary body)
40 Substrate 42 Magnetosensitive element 33 Case 21 Magnet holder 25 Permanent magnet 30 Circuit unit 31 First case body (partition member)
32 Second case body 35 Sealing agent 36 First groove portion 37 Second groove portion 50 Spacer 51 Spacer through hole 60 Jig 61 Jig cylinder 315, 325 Case body plate 316, 326 Case body side plate 318 First Recess 318a of the case body Bottom portion (partition wall) of the recess of the first case body
319 Annular groove 326a Side plate step

Claims (5)

A magnetic pole pair composed of an S pole and an N pole is formed, and a magnet body provided on the rotating body side;
A magnetosensitive element facing the magnet body;
In a magnetic rotation detection device having
Furthermore, it has a case in which the magnetosensitive element is housed inside,
The case includes a first case body having a partition wall interposed between the magnet body and the magnetic sensing element, and a second case body that covers the magnetic sensing element together with the first case body,
The first case body and the second case body are joined so as to surround the magnetic sensing element, and a sealing agent is applied to a joint portion between the first case body and the second case body ,
The magnet body and the magnetosensitive element are opposed to each other in the rotation center axis direction of the rotating body,
The partition wall is a bottom of a recess recessed toward the side where the magnet body is located, and the magnetosensitive element is disposed in the recess.
The magnetosensitive element is mounted on a substrate, and the substrate is disposed so as to overlap with a substrate receiving portion formed around the recess,
The magnetic rotation detector according to claim 1, wherein a gap is provided between the magnetosensitive element and the bottom of the recess .   The magnetic rotation detection device according to claim 1, wherein the magnet body is formed with a pair of an S pole and an N pole. The first case body includes a first plate-like portion provided with the partition wall portion, and a first side plate portion standing on an outer peripheral edge of the first plate-like portion,
The second case body includes: a second plate-like portion that faces the first plate-like portion; and a second side plate that rises toward the first side plate at an outer peripheral edge of the second plate-like portion. Have
2. The outer peripheral side surface of the case, wherein a side plate portion of one case body of the first case body and the second case body overlaps an outer surface of a side plate portion of the other case body. Or a magnetic rotation detection device according to 2; The side plate portion of the other case body includes a stepped portion that forms a first groove portion that opens toward the outer peripheral side between the side edge of the side plate portion of the one case body,
The magnetic rotation detection device according to claim 3, wherein the sealant is applied in the first groove portion . In the other case body, a cylindrical portion through which the shaft portion of the fastening member passes is continuously formed from the side plate portion of the other case body,
The one case body is formed with a notch that avoids the cylindrical portion,
Between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the notch, a second groove portion is formed that communicates with the first groove portion and opens in the direction of the rotation center axis.
The magnetic rotation detection device according to claim 4, wherein the sealant is also applied in the second groove portion .

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