JP5729727B2 - Motor with built-in magnetic rotation sensor - Google Patents

Description

  The present invention relates to a motor with a built-in magnetic rotation sensor (hereinafter sometimes simply referred to as “rotation sensor”).

  Conventionally, it has been known that an annular permanent magnet is attached to a rotating shaft of a motor, the pulse signal is detected by a pulse signal detecting element such as a Hall element, and the rotational speed of the rotating shaft is controlled. Such a rotation sensor is required to improve detection accuracy. On the other hand, miniaturization, hermeticity, improvement in maintenance performance, and cost reduction are also required for motors, and motors that solve all these problems are desired. In response to such demands, a number of improved techniques related to motors have been proposed, and examples thereof include those shown in Patent Documents 1 and 2.

JP-A-7-274443 Japanese Utility Model Publication No. 7-15326

In Patent Document 1, the rotating shaft passes through the anti-load side bracket, and the annular permanent magnet attached to the rotating shaft is recessed from the outside so as to be adjacent to the bottom surface of the cylindrical portion that supports the bearing of the anti-load side bracket. A motor having a structure in which a cover body that is exposed in a provided recess and contains a printed circuit board on which a pulse signal detection element is mounted is fitted in the recess so as not to protrude outward of the recess. Is disclosed.
According to the above configuration, the surface on the side opposite to the load side of the motor can be smoothed and flattened, and since the pulse signal detection element is located away from the coil, it is not affected by the rotating magnetic field of the coil. Since the body can be clamped and fixed in the recess of the non-load side bracket so that it cannot swing, there will be no displacement between the pulse signal detection element and the permanent magnet. It is supposed to be possible.

Patent Document 2 discloses a cap including a pulse signal detection element in which an annular permanent magnet attached to a rotating shaft extending beyond a counter load side bearing of a motor is exposed from an opening of a counter load side bracket. A motor having a configuration in which a (detecting element mounting body) is attached to the opening is disclosed.
According to the above configuration, since the pulse signal detection element is located away from the coil and is not affected by the rotating magnetic field of the coil, the detection accuracy of the rotation sensor can be improved. In addition, since the opening of the anti-load side bracket is closed with a cap from the outside, the pulse signal detection element and the permanent magnet can be easily replaced without removing the anti-load side bracket from the stator core. It is supposed to be possible.

  Incidentally, in order to improve the detection accuracy of the magnetic rotation sensor, as shown in FIG. 7, the distance A, the direction B, the inclination C, the axis between the annular permanent magnet 24 and the pulse signal detection element 22 are shown. It is necessary to optimize the position D in the direction (hereinafter collectively referred to simply as “relative position”). In other words, it is necessary to arrange the pulse signal detection element 22 parallel to and perpendicular to the permanent magnet 24. However, since the motor vibrates when driven, in order to maintain the relative position between the permanent magnet 24 and the pulse signal detecting element 22 optimally, the motor may be configured to eliminate the influence of the vibration as much as possible. desirable.

  Here, the motor has a motor case, and the motor case generally includes a cylindrical frame and brackets (load-side bracket and anti-load-side bracket) that are fitted to openings on both sides of the frame. In order to reduce the vibration of itself, it is necessary to increase the rigidity of the frame and both brackets. When the cover body or cap is attached to the anti-load side bracket as in Patent Documents 1 and 2, when the cover body or cap is attached to the anti-load side bracket, the pulse signal detection element and the permanent member are permanently attached. It is difficult to adjust the relative position with the magnet to an optimum one, and in this respect, the detection accuracy of the rotation sensor cannot be improved. Further, in order to reduce the influence of the vibration of the motor, a structure for increasing the rigidity of the cover body or the cap itself or firmly connecting and fixing the cover body or the cap to the anti-load side bracket is required. Furthermore, since there is a structure for connecting and fixing, the dimension in the axial direction becomes large. In the first place, the number of parts increases by the amount of the cover body or cap. For this reason, an increase in production cost is caused, and it is impossible to achieve both improvement in detection accuracy of the rotation sensor and reduction in production cost. Further, since the cover body or the cap is attached from the outside of the anti-load side bracket, the sealing portion of the rotation sensor housing is poor and the dustproof and waterproof performance is poor.

  In view of the above-described problems of the prior art, an object of the present invention is to provide a motor that is compact, low in production cost, high in hermeticity, and high in detection accuracy of a rotation sensor.

The present invention incorporates a load-side bracket and an anti-load-side bracket that are fitted into an opening of a cylindrical frame, a magnetic rotation sensor including a pulse signal detection element, an element case, and an annular permanent magnet ,
A first load side tube portion and a second load side tube portion having a smaller diameter than the first load side tube portion are provided inside the load side bracket and outside the first load side tube portion. And
A first anti-load side tube portion on the inner side of the anti-load side bracket and a second anti-load having a smaller diameter than the first anti-load side tube portion on the outside of the first anti-load side tube portion. A side tube is provided,
Load bearing and non-load-side bearing is mounted on the rotary shaft, the first counter-load-side cylindrical portion of the load-side cylindrical portion or the first, the first load-side cylindrical portion or the first anti-load side It is fitted so as to be in contact with the step portion of the tube portion and the second load side tube portion or the second anti-load side tube portion,
In the motor in which the outer diameter of the annular permanent magnet is smaller than the inner diameter of the second anti-load side cylindrical portion, and the annular permanent magnet is attached to a portion extending from the anti-load side bearing of the rotating shaft,
Wherein to case fitting portion on the inner surface of the anti-load side bracket of the second outer diameter direction from the side wall of the anti-load side cylindrical portion is provided,
The element case is fitted into the case fitting portion so that the pulse signal detection element is exposed at a position corresponding to the annular permanent magnet,
The problem is solved by a magnetic rotation sensor built-in motor in which the element case and the anti-load side bearing are adjacent to each other.

According to the present invention, since the element case to which the pulse signal detection element is attached is directly attached to the anti-load side bracket having high rigidity, the influence of vibration of the motor can be eliminated as much as possible. The bearings on both sides attached to the rotary shaft can be connected to the first load-side cylinder part or the first anti-load-side cylinder part in the first load-side cylinder part or the first anti-load-side cylinder. Is inserted so as to be in contact with the step portion between the first load side cylinder portion and the second load side cylinder portion or the second anti-load side cylinder portion. The movement accuracy of the rotation sensor can be improved. Further, the element case is fitted into a case fitting portion provided on the inner side surface of the anti-load side bracket in the outer diameter direction from the side wall of the second anti-load side cylinder portion inside the anti-load side bracket. Therefore, since the space for the rotation sensor can be kept to a minimum, the motor can be made compact. In addition, since a cover body and cap to be attached to the non-load side bracket are not required, the number of parts is small and the airtightness is high, so the production cost is low and the dustproof and waterproof performance is high. Further, since the anti-load side bearing, which is a magnetic material, is arranged like a wall between the annular permanent magnet and the motor, the influence of the rotating magnetic field of the motor is concentrated on the anti-load side bearing. The influence of the rotating magnetic field on can be greatly reduced.

Further, since the case and the counter-load-side bearing element is adjacent, not only compact in the axial direction by counter-load-side bearing holding the casing element, the axial displacement of the element case for due to vibration Therefore, the detection accuracy of the rotation sensor can be further increased. If the element case has a convex portion and the case fitting portion of the anti-load side bracket has a concave portion corresponding to the convex portion, the element case is fitted into the case fitting portion. Positioning becomes easy, and displacement of the element case due to vibration can be prevented. Further, if the frame and the fitting portion of both brackets and the space between the rotating shaft and the bracket are sealed, the airtightness can be further improved, and a motor excellent in dustproof / waterproof performance can be obtained.

  Further, by interposing a cylindrical non-magnetic member between the annular permanent magnet and the rotating shaft, the weak magnetism transmitted from the rotating shaft to the annular permanent magnet can be cut off, and the detection accuracy of the rotation sensor is further improved. be able to. Furthermore, if the non-magnetic member has a flange portion on the load side bracket side, the magnetism from the anti load side bearing can be cut off even if the distance between the annular permanent magnet and the anti load side bearing is reduced. As a result, the protrusion of the annular permanent magnet portion can be suppressed, so that axial compactness can be achieved. In addition, the structure by which a flange part is arrange | positioned at the anti-load side bracket side may be sufficient, and it is good to provide a space | gap between an annular permanent magnet and an anti-load side bearing in this case. In order to prevent rotation between the annular permanent magnet and the nonmagnetic member, it is preferable to provide a rotation preventing means.

  In addition, it is preferable to extend the rotating shaft to the outside of the non-load side bracket and attach the fan because the motor can be cooled.

The longitudinal cross-sectional view of 1st embodiment of this invention. The side view of the anti-load side bracket of 1st embodiment of this invention. The longitudinal cross-sectional view of the anti-load side bracket of 1st embodiment of this invention. The principal part expansion longitudinal cross-sectional view of 1st embodiment of this invention. The figure showing the variation of the annular permanent magnet of this invention, and a nonmagnetic member. The longitudinal cross-sectional view of 2nd embodiment of this invention. The figure explaining the relationship between an annular permanent magnet and a pulse signal detection element.

  An embodiment of the present invention will be described with reference to FIGS. However, the present invention is not limited to this embodiment.

  As shown in FIG. 1, the motor 10 of the present invention has a motor case 11 including a cylindrical frame 14, a load side bracket 16 that fits in an opening of the frame 14, and an anti-load side bracket 12. The rotating shaft 18 of the motor 10 is pivotally supported by a load side bearing 13 and an anti-load side bearing 15. The load side bracket 16 is provided with a first load side cylinder portion 161 and a second load side cylinder portion 162 having a smaller diameter than the first load side cylinder portion 161 on the inner side. The first anti-load side cylinder part 121 and the second anti-load side cylinder part 122 having a smaller diameter than the inner diameter of the first anti-load side cylinder part 121 are provided inside thereof. The load-side bearing 13 and the anti-load-side bearing 15 are connected to the first load-side cylinder part 161 or the first anti-load-side cylinder part 121 in the first load-side cylinder part 161 or the first anti-load-side cylinder part 121. And the second load side cylinder part 162 or the second anti-load side cylinder part 122 so as to be in contact with the stepped part. As a result, the axial movement of the rotating shaft 18 is prevented, and therefore the annular permanent magnet 24 attached to the rotating shaft 18 is prevented from moving in the axial direction. It should be noted that if the fitting portion 17 between the frame 14 and the load side bracket 16 and the anti-load side bracket 12 and the space between the rotating shaft 18 and the load side bracket 16 are sealed, the hermeticity of the motor 10 is improved, and dustproof / waterproof performance. Can be increased.

  Next, the magnetic rotation sensor 20 of the present invention will be described. The rotation sensor 20 includes an annular permanent magnet 24, a pulse signal detection element 22 such as a Hall element, an insulator element case 26, and a sensor signal line 28.

  First, the annular permanent magnet 24 is attached to a portion of the rotating shaft 18 that extends ahead of the anti-load side bearing 15, and the outer diameter thereof is smaller than the inner diameter D 1 of the second anti-load side cylindrical portion 122. It is. This is because when the motor 10 is assembled, the anti-load side bearing 15 is attached to the rotary shaft 18, the annular permanent magnet 24 is thereafter attached, and the anti-load side bearing 15 is attached to the first anti-load side cylindrical portion 121. In order to pass through the process of fitting until it contacts the step part of the 1st anti-load side cylinder part 121 and the 2nd anti-load side cylinder part 122, the diameter of the annular permanent magnet 24 is the 2nd anti-load side cylinder part 122. This is because the anti-load-side bearing 15 cannot be fitted into the first anti-load-side cylindrical portion 121 when the diameter is larger than the inner diameter D1. Thus, since the anti-load side bearing 15 which is a magnetic body is arranged like a wall between the annular permanent magnet 24 and the motor, the influence of the rotating magnetic field of the motor is concentrated on the anti-load side bearing 15. Therefore, the influence of the rotating magnetic field on the annular permanent magnet 24 can be extremely reduced.

Next, the pulse signal detection element 22 is covered with an element case 26, and the element case 26 extends in the outer diameter direction from the side wall of the second anti-load side cylindrical portion 122 as shown in FIGS. It is fitted in a case fitting portion 123 provided on the inner surface of the non -load-side bracket 12. If the thickness of the non-load-side bracket 12 is sufficient, the case fitting portion 123 that can fit the entire element case 26 may be used. As described above, since the element case 26 is fitted into the non-load-side bracket 12, the number of parts is small, and the motor 10 can be made compact in the axial direction. At this time, the attachment position of the element case 26 to the case fitting portion 123 is adjusted so that the relative position between the pulse signal detection element 22 and the annular permanent magnet 24 is optimized. As shown in FIG. 4, the element case 26 can be fixed by applying an adhesive to the contact surface 263 of the element case 26 with the case fitting portion 123 and bonding it to the case fitting portion 123. Also, as shown in FIGS. 2 to 4, if the element case 26 is provided with convex portions 261 and 262, the concave portions 124 and 125 corresponding to the case fitting portion 123 are provided, and these are fitted, Positioning of the element case 26 with respect to the case fitting portion 123 can be easily performed, and displacement of the element case 26 due to vibration of the motor 10 can be prevented. Further, as shown in FIG. 4, if the anti-load side bearing 15 is adjacent to the element case 26, the axial case becomes compact, and the element case 26 is prevented from moving in the axial direction. Can do. As described above, the movement of the annular permanent magnet 24 in the axial direction is prevented, and the element case 26 is securely fixed to the case fitting portion 123, so that the pulse signal detection element 22 and the annular permanent magnet 24 are fixed. Since the relative position can be maintained optimal, the detection accuracy of the rotation sensor 20 can be improved. Further, in order to reduce the influence of vibration of the motor 10, the thickness of the frame 14 and both brackets 12 and 16 is increased, and ribs as shown in FIG. The rigidity of the brackets 12 and 16 can be increased.

  A sensor signal line 28 shown in FIG. 1 extends into the motor and is drawn out of the motor 10 in the same manner as the power line of the motor. For this reason, the anti-load side bracket 12 side can be sealed, the sealing property of the motor 10 can be improved, and the dustproof and waterproof performance can be improved. In addition, if the fitting part 17 of the frame 14 and both the brackets 12 and 16 is sealed, the sealing performance can be further improved.

  FIG. 5 is a diagram showing a variation when the nonmagnetic member 25 is attached to the annular permanent magnet 24. The nonmagnetic member 25 has a cylindrical portion 253, and the outer surface thereof is fitted in the shaft hole of the annular permanent magnet 24. A rotating shaft 18 (not shown) is inserted through the cylindrical portion 253. By interposing the non-magnetic member 25 between the rotary shaft 18 and the annular permanent magnet 24, the weak magnetism transmitted from the rotary shaft 18 to the annular permanent magnet 24 can be cut off. Can be further enhanced. As shown in FIGS. 5A to 5C, when the annular permanent magnet 24 is sandwiched between the flange portion 254 and the claws 252 and 252a, the annular permanent magnet 24 is prevented from moving in the axial direction with respect to the nonmagnetic member 25. In addition, the annular permanent magnet 24 can be easily fitted to the nonmagnetic member 25 from the claws 252 and 252a side. When the flange portion 254 is provided, if the flange portion 254 is positioned on the load side bracket side 16 (see FIG. 1), the distance between the annular permanent magnet 24 and the anti-load side bearing 15 (see FIG. 1). The magnet from the anti-load-side bearing 15 can be cut off even if it is close, and this suppresses the protrusion of the annular permanent magnet 24 portion toward the anti-load-side bracket 17 (see FIG. 1). Therefore, the axial direction can be reduced. The flange portion 254 may be disposed on the anti-load side bracket 17 side. In this case, a gap is preferably provided between the annular permanent magnet 24 and the anti-load side bearing 15. Each of the annular permanent magnet 24 and the nonmagnetic member 25 shown in FIGS. 5A to 5C includes rotation prevention means. In the case of FIG. 5A, the notch 241 extending in the axial direction provided on the annular permanent magnet 24 and the protrusion 251 provided on the nonmagnetic member 25 corresponding to the notch 241 are fitted to each other, thereby Mutual rotation of the permanent magnet 24 and the nonmagnetic member 25 is prevented. In the case of FIG. 5B, a notch 241a extending in a direction perpendicular to the axial direction provided in the annular permanent magnet 24a and a protrusion 251a provided in the nonmagnetic member 25 corresponding to the notch 241a are provided. In the case of FIG. 5C, the non-magnetic member 25b having an axial hole shape having two flat surfaces 242 of the annular permanent magnet 24b and two flat surfaces 255 corresponding to the axial hole shape. By fitting the outer surface shape of the cylindrical portion 253, the mutual rotation of the annular permanent magnet 24 and the nonmagnetic member 25 is prevented. In addition, if the axial hole shape of the annular permanent magnet 24b and the outer surface shape of the cylindrical portion 253 are shapes having at least one plane, the mutual rotation of the annular permanent magnet 24 and the nonmagnetic member 25 is prevented. Thus, if the mutual rotation of the annular permanent magnet 24 and the nonmagnetic member 25 is prevented, the detection accuracy of the rotation sensor 20 can be further improved.

  FIG. 6 is a diagram showing a motor 10a according to the second embodiment of the present invention. Since the rotation sensor 20 is the same as that of the motor 10, the description about this point is omitted. The rotating shaft 18a of the motor 10a passes through the anti-load side bracket 12a and includes a fan 40. For this reason, since the fan 40 blows with respect to the anti-load side bracket 12a and the flame | frame 14, and can cool these, the heat_generation | fever of the motor 10a can be suppressed. In addition, a seal member is provided between the fitting portion 17 between the frame 14 and the anti-load side bracket 12a and the load side bracket (not shown), and between the rotating shaft 18a and the anti load side bracket 12a and the load side bracket (not shown). If 42 is provided and sealed, the sealing property of the motor 10a can be improved, and the dustproof / waterproof performance can be improved.

  As described above, the bearing of the rotating shaft is connected to the first load-side cylinder portion or the first anti-load-side cylinder portion of the load-side bracket and the anti-load-side bracket. Fits in contact with the step part of the anti-load side cylinder part and the second load side cylinder part or the second anti-load side cylinder part having a smaller diameter, and extends from the anti-load side bearing of the rotating shaft. An annular permanent magnet is provided, and an element case including a pulse signal detection element is fitted into the anti-load side bracket, so that it is compact, low in production cost, high in environmental resistance, and has a rotation sensor. A motor with high detection accuracy can be provided.

DESCRIPTION OF SYMBOLS 10, 10a Motor 12, 12a Anti-load side bracket 121 1st anti-load side cylinder part 122 2nd anti-load side cylinder part 123 Case fitting part 124, 125 Recess 13 Load side bearing 14 Frame 15 Anti load side bearing 16 Load-side bracket 161 First load-side tube portion 162 Second load-side tube portion 17 Fitting portion 18, 18a Rotating shaft 20 Magnetic rotation sensor 22 Pulse signal detection elements 24, 24a, 24b Annular permanent magnets 241, 241a Notch 25, 25a, 25b Nonmagnetic member 251, 251a Protrusion 252, 252a Claw 253 Tube 254 Flange 26 Element case 261, 262 Protrusion 40 Fan

Claims (10)

Built- in magnetic rotation sensor comprising a load side bracket and an anti-load side bracket fitted in the opening of the cylindrical frame, a pulse signal detection element, an element case and an annular permanent magnet ,
A first load side tube portion and a second load side tube portion having a smaller diameter than the first load side tube portion are provided inside the load side bracket and outside the first load side tube portion. And
A first anti-load side tube portion on the inner side of the anti-load side bracket and a second anti-load having a smaller diameter than the first anti-load side tube portion on the outside of the first anti-load side tube portion. A side tube is provided,
Load bearing and non-load-side bearing is mounted on the rotary shaft, the first counter-load-side cylindrical portion of the load-side cylindrical portion or the first, the first load-side cylindrical portion or the first anti-load side It is fitted so as to be in contact with the step portion of the tube portion and the second load side tube portion or the second anti-load side tube portion,
In the motor in which the outer diameter of the annular permanent magnet is smaller than the inner diameter of the second anti-load side cylindrical portion, and the annular permanent magnet is attached to a portion extending from the anti-load side bearing of the rotating shaft,
Wherein to case fitting portion on the inner surface of the anti-load side bracket of the second outer diameter direction from the side wall of the anti-load side cylindrical portion is provided,
The element case is fitted into the case fitting portion so that the pulse signal detection element is exposed at a position corresponding to the annular permanent magnet,
The element case and the anti-load side bearing are adjacent to each other,
Motor with built-in magnetic rotation sensor. The motor with a built- in magnetic rotation sensor according to claim 1, wherein the element case has a convex portion, and the case fitting portion has a concave portion corresponding to the convex portion. The motor with a built-in magnetic rotation sensor according to claim 1 or 2 , wherein the annular permanent magnet is attached to the rotating shaft via a cylindrical nonmagnetic member. The motor with a built-in magnetic rotation sensor according to claim 3 , wherein the nonmagnetic member has a flange portion on the load side bracket side. The motor with a built-in magnetic rotation sensor according to claim 3 or 4 , further comprising means for preventing rotation between the annular permanent magnet and the nonmagnetic member. The motor with a built-in magnetic rotation sensor according to claim 5 , wherein the rotation preventing means is a notch provided in the annular permanent magnet and a protrusion provided in the nonmagnetic member corresponding to the notch. The outer surface of the cylindrical portion of the nonmagnetic member is fitted in the shaft hole of the annular permanent magnet,
6. The magnetic type according to claim 5 , wherein the rotation preventing means has an axial hole shape having at least one plane of the annular permanent magnet and an outer surface shape of the cylindrical portion of the nonmagnetic member corresponding to the axial hole shape. Motor with built-in rotation sensor. The motor with a built-in magnetic rotation sensor according to any one of claims 1 to 7 , wherein the rotation shaft passes through the anti-load side bracket and a fan is provided. The magnetic type according to any one of claims 1 to 7 , wherein a fitting portion between the frame, the load side bracket and the anti-load side bracket is sealed, and a space between the rotating shaft and the load side bracket is sealed. Motor with built-in rotation sensor. The motor with a built-in magnetic rotation sensor according to claim 8 , wherein a space between the rotating shaft and the anti-load side bracket is sealed, and a space between the rotating shaft and the load side bracket and the anti-load side bracket is sealed. .

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