JP2010233446A - Geared motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a geared motor which raises the accuracy of detecting a rotational position of an output member by minimizing a detection error in the rotational position of the output member caused by a difference in the direction of rotation. <P>SOLUTION: The geared motor includes a motor 10, an output member 14 to which the driving force of the motor 10 is transmitted through a gear train 12, a magnetic detection element 16 for detecting the rotational position of the output member 14 and a magnetic material 18 which is paired with the magnetic detection element 16. The output member 14 is provided with an input unit 141 into which the driving force of the motor transmitted to the gear train 12 is input, an output unit 142 from which the driving force of the motor input to the input unit 141 is outputted, and an extension 143 projected radially outward from the input unit 141 and the output part 142, wherein either the magnetic detection element 16 or the magnetic material 18 is fixed to the vicinity of the outer wall in the radial direction of the extension 143. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a geared motor, and more particularly, to a magnetic detection element for detecting the rotational position of an output member driven by the motor and a geared motor including a magnetic material sensed by the magnetic detection element.

  For example, as described in Patent Document 1, a geared motor that outputs rotational power of a motor via a plurality of gears is known. In the geared motor described in Patent Document 1, a magnet is embedded in a driven gear integrally formed with an output shaft (output member), and a magnetic detection element mounted on a substrate is disposed at a position facing the magnet. Thus, the rotational position of the output shaft can be detected.

  In the driven gear of this cited document 1, in order to prevent a reduction in strength of the tooth portion serving as an input portion for power transmission, the magnet is disposed away from the tooth portion and disposed inside the driven gear. Moreover, since the magnet is separated from the tooth portion, the vicinity of the tooth portion is not deformed by the stress applied to the tooth portion, and the magnet position is not shifted.

JP 2004-229378 A

  When the output shaft and the driven gear are configured as a transmission member integrally formed as in Patent Document 1, the power from the motor side input from the tooth portion is output from the output shaft. Therefore, when the magnet is disposed at a midway position from the tooth portion to the output shaft, that is, at a midway position of the power transmission path as in Patent Document 1, when a large stress is applied to a driven body (not shown), A large stress is also applied between the toothed portion of the driven gear and the output shaft, and the intermediate position between the output shaft and the toothed portion where the magnet is disposed is deformed, the position of the magnet is changed, and the detection accuracy is lowered. The first problem is that

  Furthermore, in the case of the geared motor of Patent Document 1, there is a second problem that the detection error increases depending on the rotation direction as compared with the case where the magnet is disposed outside the driven gear. This problem will be described with reference to FIG. FIG. 10 illustrates the difference in the detection position of the magnet in the magnetic detection element when the output shaft (output member) is rotated clockwise or counterclockwise in order to explain the problem of the geared motor of Patent Document 1. It is explanatory drawing for demonstrating.

  For example, when the magnetic field generated from the magnet 72 is a magnetic field MF as shown in FIG. 10 (this shape is merely an example), the position where the magnet 72 can be detected by the magnetic detection element 70 is shown in FIG. It is assumed that the outermost magnetic field lines of the magnetic field MF and the detection point P overlap each other. When an output shaft (not shown) rotates clockwise around the point C in FIG. 10, the magnet 72 rotates clockwise. In this case, the magnet 72 is detected at a position where the outermost magnetic field line of the magnetic field MF and the detection point P overlap on the left side (left side from the central axis A) in FIG. On the other hand, when an output shaft (not shown) rotates counterclockwise, the magnet 72 rotates counterclockwise. In this case, the magnet 72 is detected at a position where the outermost magnetic field line of the magnetic field MF and the detection point P overlap on the right side (right side from the central axis A) in FIG. That is, the detection position of the magnet 72 by the magnetic detection element 70 is on the left side or the right side of the central axis A depending on the rotation direction of the output shaft (magnet 72). As a result, the detection position of the magnet in the magnetic detection element when the output shaft is rotated clockwise or counterclockwise is greatly different.

  The amount of deviation of the detection position of the magnet in the rotation direction of the output shaft (magnet 72) (hereinafter simply referred to as detection error) is relative to the case where the magnet 72 is relatively disposed inside (FIG. 10A). As can be seen from a comparison with the case where the magnet 72 is disposed on the outer side (FIG. 10B), the case where the magnet 72 is disposed on the inner side is larger than the case where the magnet 72 is disposed on the outer side. That is, in the case of FIG. 10A, the angle at which the straight line connecting the point C and the detection point P intersects with the straight line connecting the point C and the detection body 72 is relatively large. In the case of FIG. Since the angle at which the straight line connecting C and the detection point P intersects with the straight line connecting the point C and the detection body 72 is relatively small, the detection error due to the difference in the rotation direction of the output shaft (magnet 72) The case where it arrange | positions inside becomes larger than the case where it arrange | positions outside.

  In view of the above problems, the problem to be solved by the present invention is to suppress the detection error of the rotation position of the output member due to the difference in the rotation direction in the output member as the transmission member that outputs the transmitted driving force. An object of the present invention is to provide a geared motor with improved detection accuracy of the rotational position of the output member.

  In order to solve the above problems, a geared motor according to the present invention includes a motor, and an output member that transmits the driving force of the motor through the gear train, and outputs the transmitted driving force of the motor. In a geared motor comprising a magnetic detection element for detecting the rotational position of the output member and a magnetic body that forms a pair with the magnetic detection element, the output member is driven by the motor transmitted to the tooth wheel train. An input part to which force is input, an output part from which the driving force of the motor input to the input part is output, and an extending part projecting radially outward from the input part and the output part are integrated. It is provided by molding, and the gist is that either the magnetic detection element or the magnetic body is fixed in the vicinity of the outer wall in the radial direction of the extending portion.

  According to the geared motor according to the present invention, the output member is formed with an input portion to which the driving force of the motor is input and an output portion for transmitting to the driven body, and the radial direction from the input portion and the output portion. An extending portion protruding outward is provided by integral molding. Therefore, either the magnetic detection element or the magnetic body for detecting the rotation position of the output member can be fixed in the vicinity of the outer wall in the radial direction of the extending portion that protrudes outward. The detection error of the rotation position of the output member due to the difference in rotation direction can be suppressed to a small level. In addition, the magnetic body is not disposed at the midway position between the input unit and the output unit, but at the extended portion positioned outside the input unit and the output unit with a relatively small amount of deformation even when a large force is applied to the output member. Therefore, the change in the position of the magnetic body can be suppressed to a small level. Therefore, the detection accuracy of the rotational position of the output member can be increased as compared with the case where a power transmission portion such as a gear tooth portion is provided on the outer peripheral side of the output member as in the prior art. Furthermore, since the output member is provided with the input portion, the output portion, and the extending portion by integral molding, the number of parts can be reduced.

  Moreover, in this invention, it is preferable that the said input part and the said output part are arrange | positioned in the position which mutually overlaps in the radial direction of the said output member. If comprised in this way, an output member can be made small in a radial direction by the part which the input part and the output part overlapped in the radial direction. In particular, if the output unit is arranged on the axis of the input unit (on the rotation axis), the input unit and the output unit can be arranged close to each other in the radial direction, and the output member is arranged in the radial direction. It can be made small.

  Furthermore, in this invention, it is preferable that the said extension part is provided in the position which overlaps with the said input part or the said output part in the axial direction of the said output member. As described above, when the extending portion to which either the magnetic detection element or the magnetic body is fixed is provided so as to overlap the input portion or the output portion in the axial direction of the output member, the size of the output member in the axial direction is increased. Therefore, the size of the geared motor can be made more compact. In particular, if the magnetic detection element or the magnetic body is provided at a position overlapping the input portion or the output portion in the axial direction of the output member, the size of the output member in the axial direction can be further reduced. it can.

  Furthermore, in the present invention, in the axial direction of the output member, the output member has a hole portion opened to one side and a hole portion opened to the other, and the input portion is formed in the hole portion opened to the one side. The output portion is formed in the hole opening in the other, and the extending portion is formed in the outer side in the radial direction of the hole opening in the one or the hole opening in the other, and the magnetic detection element or the magnetic body Is preferably provided at a position overlapping the one hole or the other hole in the axial direction of the output member. In this way, by forming the hole portion in which the input portion or the output portion is formed in the radial direction of the extending portion to which the magnetic detection element or the magnetic body is fixed, the magnetic detection element or the magnetic body is attached to the output member. Since it can be provided so as to overlap the input portion or the output portion in the axial direction, the size of the output member in the axial direction can be reduced.

  In the present invention, it is preferable that the hole portion opened to the one side and the hole portion opened to the other side are through holes that are connected to each other and penetrate the output member in the axial direction. If comprised in this way, an input part and an output part can be closely arranged in an axial direction. That is, the input side member engaged with the hole portion as the input portion by not forming a thick wall portion between the input portion and the output portion, and the output side engaged with the hole portion as the output portion The members can be arranged close to each other in the axial direction, and the size of the geared motor can be made compact only in the wall portion.

  In addition, when the magnetic detection element and the magnetic body are arranged so as to face each other in the axial direction, the extension portion is in contact with the axial line with which either the magnetic detection element or the magnetic body abuts. It is preferable that a recess having a vertical contact surface is formed.

  In the configuration in which the magnetic detection element and the magnetic body face each other in the axial direction, the detection sensitivity of the magnetic body by the magnetic detection element depends on the distance between the two in the axial direction. Since either one faces the other in a state of being positioned by the contact surface of the recess, variation in the distance between the two products is suppressed, and a geared motor with small variation in detection accuracy between products can be obtained. .

  Further, in this case, the extending portion may be formed of resin, and the opening of the concave portion may be sealed by heat sealing.

  Thus, if the opening of the concave portion is sealed using heat fusion, either the magnetic detection element or the magnetic body can be easily fixed to the extending portion.

  In addition, it is preferable that the extending portion is formed with a pair of tongue pieces on which either the magnetic detection element or the magnetic body protruding outward from the outer wall surface is held.

  By providing such a tongue piece, either the magnetic detection element or the magnetic body can be disposed more radially outside the output member. Therefore, the detection error of the rotation position of the output member due to the difference in the rotation direction of the output member can be further reduced. In addition, when the magnetic body is fixed so that the radial outermost portion of the magnetic body corresponds to the portion where the tips of the pair of tongue pieces are separated from each other, the outer periphery of the magnetic body in the radial outermost direction is thick. No need to form walls. With this configuration, the size of the extending portion in the radial direction can be reduced as compared with the configuration in which the magnetic body is embedded in the extending portion.

  According to the geared motor according to the present invention, the output member is formed with an input portion to which the driving force of the motor is input and an output portion for transmitting to the driven body, and the radial direction from the input portion and the output portion. An extending portion protruding outward is provided by integral molding. Therefore, either the magnetic detection element or the magnetic body for detecting the rotation position of the output member can be fixed in the vicinity of the outer wall in the radial direction of the extending portion that protrudes outward. The detection error of the rotation position of the output member due to the difference in rotation direction can be suppressed to a small level. In addition, the magnetic body is not disposed at the midway position between the input unit and the output unit, but at the extended portion positioned outside the input unit and the output unit with a relatively small amount of deformation even when a large force is applied to the output member. Therefore, the change in the position of the magnetic body can be suppressed to a small level. Therefore, the detection accuracy of the rotational position of the output member can be increased as compared with the case where a power transmission portion such as a gear tooth portion is provided on the outer peripheral side of the output member as in the prior art. Furthermore, since the output member is provided with the input portion, the output portion, and the extending portion by integral molding, the number of parts can be reduced.

It is an external view (state which removed the upper case) of the geared motor which concerns on this embodiment. It is the external view (state which removed the upper case and the lower case) which looked at the geared motor shown in FIG. 1 from the side surface. FIG. 3 is an exploded perspective view of the geared motor shown in FIGS. 1 and 2. 4A is an external view of the output member viewed from the output unit side, and FIG. 4B is an external view of the output member viewed from the input unit side. It is the top view which showed the state which removed the upper case and the output member from the geared motor shown in FIGS. FIG. 6A is a modified example of the output member included in the geared motor shown in FIGS. 1 to 3, FIG. 6A shows a state where a magnetic body is attached to the output member, and FIG. 6B shows a state where the magnetic body is attached to the output member. Indicates a state that has not been performed. It is a schematic diagram of the stop position of the output member on the substrate when one magnetic body fixing hole is selected from the four magnetic body fixing holes formed in the extended portion of the output member and the magnetic body is fixed ( Example 1). Schematic diagram of the stop position of the output member on the substrate when the magnetic body is fixed by selecting two magnetic body fixing holes on the diameter from the four magnetic body fixing holes formed in the extended portion of the output member (Example 2). From the four magnetic body fixing holes formed in the extended part of the output member, two magnetic body fixing holes adjacent on the circumference are selected, and the magnetic body and the S pole where the N pole faces the magnetic detection element (Example 3) which is a schematic diagram of the stop position of the output member on a board | substrate when the magnetic body which opposes a magnetic detection element is fixed. Explanatory drawing for demonstrating the difference in the detection position of the magnet in a magnetic detection element at the time of rotating an output shaft (output member) clockwise and counterclockwise in order to demonstrate the problem of the geared motor of patent document 1 It is.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an external view of the geared motor 1 according to the present embodiment (with the upper case 91 removed), and FIG. 2 is an external view of the geared motor 1 viewed from the side (the upper case 91 and the lower case 92 are shown). Removed state). FIG. 3 is an exploded perspective view of the geared motor 1.

  The geared motor 1 according to the present embodiment includes a motor 10 that is a drive source, a tooth wheel train 12 that reduces the rotation of the motor 10 at a predetermined reduction ratio and transmits the rotation to the output member 14, and the tooth wheel train 12. The output member 14 that outputs the transmitted rotation of the motor 10 to the driven body, the magnetic detection element 16 for detecting the rotational position of the output member 14, and the magnetic detection element 16 are paired with the output member. 14 and a magnetic body (magnet) 18 fixed to 14.

  The motor 10 is a known DC motor and includes a shaft 101 that transmits power. A first gear 121 is fixed to the tip of the shaft 101 by press fitting. The tooth wheel train 12 includes a first gear 121 press-fitted into the shaft 101, a second gear (composite gear) 122 that meshes with the first gear 121, and a third gear that meshes with the second gear 122. (Composite gear) 123, fourth gear (composite gear) 124 meshed with third gear (composite gear) 123, a plurality of planetary gears 126 supported by carrier 125, and fixed to lower case 92 A fixed gear 127. The second gear 122, the third gear 123, and the fourth gear 124 are rotatably supported by shafts provided in the lower case 92.

  The tooth wheel train 12 will be specifically described. The first gear 121 meshes with the large-diameter gear 122 a of the second gear 122. The small diameter gear 122 b of the second gear 122 meshes with the large diameter gear 123 a of the third gear 123. The small diameter gear 123b of the third gear 123 meshes with the large diameter gear 124a of the fourth gear 124. The fourth gear 124 is formed with a sun gear 124 b coaxially with the large-diameter gear 124 a and meshes with the planetary gear 126. The fixed gear 127 has an inner gear 127 a formed on the inner peripheral surface, and meshes with the planetary gear 126. The fixed gear 127 includes a motor support portion 127b that supports the side surface of the motor 10, a protrusion (not shown) for fixing the substrate 20, and a substrate support portion 127c that supports the substrate 20 and prevents the substrate 20 from being bent. Have The sun gear 124b, the carrier 125, the planetary gear 126, and the internal gear 127a constitute a planetary gear mechanism.

  The power of the motor 10 is transmitted to the rotation transmission member 13 through the toothed wheel train 12. The rotation transmitting member 13 includes a main body 131, a shaft 132 that protrudes downward from the main body 131, and a spline shaft 133 that protrudes upward opposite to the shaft 132. The shaft 132 is inserted into a through hole 124 c formed in the fourth gear 124 and a through hole 125 a formed in the carrier 125. Further, internal teeth (not shown) are formed on the inner peripheral surface of the main body 131, and the power of the motor 10 is transmitted to the rotation transmission member 13 by meshing the internal teeth with the planetary gear 126.

  An output member 14 is engaged with the rotation transmission member 13 configured as described above by a spline shaft 133. FIG. 4 is an enlarged view showing the output member 14 in an enlarged manner. Here, FIG. 4A is an external view of the output member 14 viewed from the output unit 142 side, and FIG. 4B is an external view of the output member 14 viewed from the input unit 141 side. FIG. 4A shows a state where the magnetic body 18 is not yet fixed to the output member 14.

  The output member 14 is connected to a spline shaft 133 of the rotation transmission member 13, and an input portion (spline hole) 141 to which the driving force of the motor 10 is input is connected to a driven body (not shown). Are output to the outside (connection hole) 142, and an input portion 141 and a flange-like extending portion 143 projecting outward from the output portion 142 in the radial direction. The output member 14 is configured as a transmission member that transmits the driving force of the motor 10 transmitted from the rotating member 13 to a driven body (not shown).

  Here, in this embodiment, the input part 141 and the output part 142 are respectively formed in a hole part opened in one of the axial direction of the output member 14 and a hole part opened in the other. Therefore, since the input part 141 and the output part 142 are arranged at positions where they overlap each other in the radial direction of the output member 14, the output member 14 is equivalent to the part where the input part 141 and the output part 142 overlap in the radial direction. Can be reduced in the radial direction. Further, in the present embodiment, the output unit 142 is disposed on the axis of the input unit 141 (on the rotation axis). Therefore, the input part 141 and the output part 142 can be disposed close to each other in the radial direction, and the output member 14 can be further reduced in the radial direction.

  The extending portion 143 is formed with four cylindrical magnetic body fixing holes (corresponding to concave portions in the present invention) 144 at substantially equal intervals on the circumference, and a cylinder is formed in one of the magnetic body fixing holes 144. The shaped magnetic body 18 is fixed. Up to four magnetic bodies 18 can be fixed, and a specific description will be given later. The magnetic body fixing hole 144 extends in the axial direction of the output member 14, and has an opening 144a opened in one of the axial directions, and a bottom surface 144b perpendicular to the axial line of the output member 14 (contact in the present invention). This corresponds to a surface.). Note that the opening 144 a opens toward the output portion 142 in the axial direction of the output member 14.

  The magnetic body 18 of the present embodiment is formed in a columnar shape that is loosely fitted in a magnetic body fixing hole 144 formed in a cylindrical shape, and N and S poles are magnetized in two directions in the axial direction. Further, the magnetic body 18 is inserted into the magnetic body fixing hole 144 from the opening 144a, and is fixed in a state where any one of the N pole and the S pole is in contact with the bottom surface 144b.

  Further, the extending portion 143 is formed with a size (width) of at least twice the diameter of the magnetic body 18 in the radial direction. The magnetic body fixing hole 144 formed in the extending portion 143 is located on the outer side in the radial direction from the input portion (spline hole) 141 and the output portion (connection hole) 142. Therefore, since the magnetic body fixing hole 144 is not disposed in the middle of the power transmission path, even when a large stress is applied to the driven body (not shown), the magnetic body fixing hole 144 has a large stress. It does not take. Therefore, the change in the position of the magnetic body 18 can be suppressed to a small level. The inner diameter of the cylindrical portion 142b of the output portion (connection hole) 142 and the inner diameter of the large-diameter portion 141a of the input portion (spline hole) 141 are formed to have substantially the same diameter.

  Furthermore, in the case of this embodiment, as shown in FIG. 4, the magnetic body 18 is fixed in the vicinity of the outer wall 143 a of the extending portion 143, and the entire magnetic body 18 is internally installed in the extending portion 143. Yes. Specifically, the outermost outer wall 18 c in the radial direction of the magnetic body 18 is disposed close to the outer wall 143 a of the extending portion 143. On the other hand, the radially innermost outer wall 18d of the magnetic body 18 is disposed closer to the outer wall 143a side of the extending portion 143 than 1/2 of the radial length from the inner wall of the cylindrical portion 142b to the outer wall 143a of the extending portion 143. ing. Therefore, the magnetic body 18 is disposed in a region closer to the outer wall 143a than ½ of the radial length from the inner wall of the cylindrical portion 142b of the output portion (connection hole) 142 to the outer wall 143a of the extending portion 143. Yes.

  As a method for fixing the magnetic body 18, any method that seals the opening 144 a by heat fusion is preferable because the magnetic body 18 can be reliably and easily sealed in the magnetic body fixing hole 144. A method of pouring molten resin and sealing the opening 144a after inserting the magnetic body 18 may be employed.

  In the present embodiment, the output unit 142 transmits power to the driven body using a groove 142a formed radially outward in a part of a cylindrical portion 142b as shown in FIG. Although configured, this configuration is exemplary. For example, a configuration in which power is transmitted by serration or D cut may be used. The input unit 141 may also be a serration hole.

  In the present embodiment, the extending portion 143 is formed at a position overlapping the input portion (spline hole) 141 and the output portion (connection hole) 142 in the axial direction of the output member 14. In particular, in the case of the present embodiment, the spline hole as the input portion 141 and the connection hole as the output portion 142 are connected to each other to form a through-hole through which the output member 14 passes in the axial direction. The magnetic body 18 is disposed radially outward of the connection position of the spline hole 141 and the output portion (connection hole) 142. Therefore, the magnetic body 18 is disposed at a position that overlaps both the input portion (spline hole) 141 and the output portion (connection hole) 142 in the axial direction. In this way, the magnetic body 18 can be provided so as to overlap the input portion (spline hole) 141 and the output portion (connection hole) 142 in the axial direction of the output member 14, so that the output member 14 extends in the axial direction. The size can be reduced.

  In the present embodiment, the magnetic detection element 16 that senses the magnetic body 18 fixed to the output member 14 is provided on the substrate 20 that is attached between the rotation transmission member 13 and the output member 14. FIG. 5 is a top view showing a state where the upper case 91 and the output member 14 are removed from the geared motor 1. As shown in FIG. 5, a through hole 201 into which the spline shaft 133 of the rotation transmitting member 13 is inserted is formed at the center of the substrate 20, and a terminal portion for connecting to a control means (not shown) or the like at the end portion. 202 is formed. In the present embodiment, the two magnetic detection elements 16 are disposed on the substrate 20 so as to face the extending portion 143 of the output member 14 in the axial direction, and are electrically connected to the terminal portion 202.

  Such components of the geared motor 1 are accommodated in a case body including an upper case 91 and a lower case 92. The lower case 92 is formed with a protrusion that supports the motor 10 and a shaft that rotatably supports the second gear 122, the third gear 123, and the fourth gear 124. The upper case 91 is formed with an insertion hole 91b through which a cylindrical portion in which the output portion 142 of the output member 14 is formed is inserted. The locking members 91 a formed in the upper case 91 are locked in locking holes 92 a formed in the lower case 92, so that the above-described components are accommodated in the case body.

  The geared motor 1 configured as described above operates as follows. When electric power is supplied to the motor 10, the shaft 101 of the motor 10 rotates. The rotation of the shaft 101 is decelerated through the second gear 122 and the third gear 123 from the first gear 121 that rotates integrally with the shaft 101, and is transmitted to the fourth gear 124. The rotation of the fourth gear is decelerated and transmitted to the rotation transmission member 13 through a planetary gear mechanism constituted by the sun gear 124b, the carrier 125, the planetary gear 126, and the internal gear 127a. When the rotation transmitting member 13 rotates, the rotation is transmitted to the input unit 41 with which the spline shaft 133 is fitted, and the output member 14 rotates. Then, the rotation of the output member 14 is transmitted to the driven body engaged through the output portion 142. Thus, the rotation of the motor 10 is decelerated at a predetermined reduction ratio by the tooth wheel train 12 and transmitted to the driven body.

  During the operation of the geared motor 1, the magnetic body 18 fixed to the output member 14 is sensed by the magnetic detection element 16. A control means (not shown) electrically connected to the geared motor 1 recognizes the rotational position of the output member 14 based on a signal generated when the magnetic detection element 16 senses the magnetic body 18.

  Hereinafter, a specific detection mode of the rotation position of the output member 14 will be described. FIG. 7 is a diagram schematically showing the stop position of the output member 14 on the substrate 20 when one magnetic body fixing hole is selected from the four magnetic body fixing holes and the magnetic body 18 is fixed. FIG. 8 is a diagram schematically showing the stop position of the output member 14 on the substrate 20 when two magnetic body fixing holes on the diameter are selected from the four magnetic body fixing holes and the magnetic body 18 is fixed. It is. In FIG. 9, two magnetic body fixing holes adjacent on the circumference are selected from the four magnetic body fixing holes, and the magnetic body 18a and the S pole in which the north pole faces the magnetic detection elements 16a ′ and 16b ′ are magnetized. It is the figure which showed typically the stop position of the output member 14 on the board | substrate 20 at the time of fixing the magnetic body 18b which opposes detection element 16a 'and 16b'. 7 to 9, the angle of the original position of the output member 14 is 0 degree (reference angle).

  First, the first embodiment shown in FIG. 7 will be described. As shown in the figure, magnetic detection elements 16a and 16b are disposed on the substrate 20 at a position of 0 degrees and a position of 180 degrees, respectively. One magnetic body 18 is attached to the extending portion 143 of the output member 14. When the output member 14 is positioned at the position shown in FIG. 7A, the magnetic detection element 16a transmits a signal, and the rotation angle of the output member 14 is detected as 0 degree, as shown in FIG. 7C. When the output member 14 is located at the position, the magnetic detection element 16b transmits a signal, the rotation angle of the output member 14 is detected as 180 degrees, and the rotation position of the output member 14 is detected every 180 degrees. become.

  Next, the second embodiment shown in FIG. 8 will be described. As shown in the figure, magnetic detection elements 16a and 16b are disposed on the substrate 20 at the 0 degree position and the 90 degree position, respectively. Two magnetic bodies 18 are attached to the extended portion 143 of the member 14 on the diameter. When the output member 14 is positioned at the position shown in FIGS. 8A and 8C, the magnetic detection element 16a senses a magnetic material and the magnetic detection element 16b has no signal. The rotation angle of the output member 14 is detected as 0 degree or 180 degrees. On the other hand, when the output member 14 is positioned at the position shown in FIGS. 8B and 8D, the magnetic detection element 16a is a no-signal and the magnetic detection element 16b is a signal in which a magnetic material is sensed. Therefore, the rotation angle of the output member 14 is detected as 90 degrees or 270 degrees. Therefore, when the discrimination between 0 degree and 180 degrees and the discrimination between 90 degrees and 270 degrees are performed on the control side, the rotational position of the output member 14 can be detected every 90 degrees. The determination is made in consideration of, for example, the initial attachment position of the magnetic body and the rotation direction of the output member 14.

  Finally, the third embodiment shown in FIG. 9 will be described. As shown in the figure, the substrate 20 has a magnetic detection capable of discriminating the polarity of the magnet at 0 degree position and 180 degree position. Elements 16a ′ and 16b ′ are respectively disposed, and the extending portion 143 of the output member 14 has a magnetic body 18a whose N pole faces the magnetic detection elements 16a ′ and 16b ′, and a peripheral position from the mounting position of the magnetic body 18a. The magnetic body 18b whose S pole is opposed to the magnetic detection elements 16a ′ and 16b ′ is attached at a position rotated 90 degrees in the direction, and the rotational position of the output member 14 is detected every 90 degrees.

  Specifically, when the output member 14 is positioned at the position shown in FIG. 9A, the signal when the magnetic detection element 16a ′ senses the N-pole magnetic material and the magnetic detection element 16b ′ is no signal. Accordingly, the rotation angle of the output member 14 is detected as 0 degree. When the output member 14 is located at the position shown in FIG. 9B, the output member 14 has a signal that the magnetic detection element 16a ′ senses no signal and the magnetic detection element 16b ′ senses the S polar magnetic material. The rotation angle of 14 is detected as 90 degrees. When the output member 14 is located at the position shown in FIG. 9 (c), the output member 14 has a signal that the magnetic detection element 16a ′ senses no signal and the magnetic detection element 16b ′ senses the N pole magnetic material. The rotation angle of 14 is detected as 180 degrees. When the output member 14 is positioned at the position shown in FIG. 9 (d), the output when the magnetic detection element 16a ′ senses the S-polar magnetic material and the magnetic detection element 16b ′ has no signal. The rotation angle of the member 14 is detected as 270 degrees.

  The number and position of the magnetic bodies 18 to be attached are not limited to those shown in the first to third embodiments of FIGS. 7 to 9, but four magnetic bodies formed at substantially equal intervals on the circumference of the extending portion 143. It can be freely selected from the fixing hole. Based on the rotational position of the output member 14, the rotation of the motor 10 is controlled by the control means so that the driven body is positioned at a predetermined position.

  The geared motor 1 according to such an embodiment can be applied to, for example, driving a valve that opens and closes a flow path. In the case of Embodiment 1 shown in FIG. 7, the rotation of the motor 10 is controlled by setting the valve connected to the output member 14 to be in a closed state at 0 ° and to be in an open state at 180 °. Thus, the opening and closing of the flow path can be freely controlled. In this case, the positions of the two magnetic detection elements 16 a and 16 b are at both ends of the driving range of the output member 14. In the case of the second embodiment shown in FIG. 8 and the third embodiment shown in FIG. 9, the valve connected to the output member 14 capable of detecting the rotational position every 90 degrees as described above is driven. Then, when the valve is opened corresponding to the rotation position of the output member 14, 0 degree, 90 degrees, 180 degrees, and 270 degrees, respectively, the closed state, small, medium, and large (fully opened state), the rotation of the motor 10 is By controlling, it becomes possible to adjust the flow rate through the valve.

  In the geared motor 1 controlled in this way, as described with reference to FIG. 4, the magnetic body 18 is formed on the extended portion 143 of the output member 14 that protrudes radially outward from the input portion 141 and the output portion 142. It is fixed. As a result, the magnetic body 18 sensed by the magnetic detection element 16 to detect the rotational position of the output member 14 is arranged on the radially outer side of the output member 14 as compared with the prior art (Patent Document 1). Become. Therefore, the detection error of the rotation position of the output member 14 due to the difference in the rotation direction can be suppressed small, and the detection accuracy of the rotation position of the output member 14 by the magnetic body 18 can be increased. In addition, the magnetic body 18 is not located in the middle of the input unit 141 and the output unit 142 but is extended to the outside of the input unit 141 and the output unit 142 with a relatively small deformation amount even when a large force is applied to the output member 14. Since it is disposed in the installation portion 143, a change in the position of the magnetic body 18 due to the deformation of the output member 14 can be suppressed, and the detection accuracy of the rotational position of the output member 14 is improved.

  Further, in the present embodiment, the magnetic body 18 is fixed to the extending portion 143 of the output member 14 in a state where the magnetic body 18 is in contact with the bottom surface 144b of the magnetic body fixing hole 144. That is, the bottom surface 144b perpendicular to the axis of the output member 14 faces the magnetic detection element 16 in a state of being positioned in the axis direction. Therefore, the variation in the gap between the magnetic detection element 16 and the magnetic body 18 can be suppressed, and the geared motor 1 with a small variation in detection accuracy for each product can be obtained.

  The extending portion 143 provided to increase the detection accuracy of the rotational position of the output member 14 is provided at a position overlapping the input portion 141 and the output portion 142 in the axial direction of the output member 14. In this way, the length of the output member 14 in the axial direction is not increased by providing the extending portion 143. That is, the position detection accuracy in the rotation direction of the output member 14 can be increased while maintaining the size of the geared motor 1 in the axial direction.

  In order to further improve the detection accuracy of the rotational position of the output member 14, a configuration in which the magnetic body 18 is fixed to the output member 14 as follows is considered as a modification. That is, as shown in FIG. 6A, the output member 14 is provided with a pair of tongue pieces 145 protruding outward from the outer wall surface of the extending portion 143, and the magnetic body 18 is sandwiched between the tongue pieces 145. It may be configured to be fixed. With this configuration, the magnetic body 18 is held in a state of protruding from the outer wall of the extending portion 143, so that the magnetic body 18 can be positioned further outside in the radial direction of the output member 14. Therefore, the detection error due to the difference in the rotation direction of the output member 14 is further reduced, and the detection accuracy of the rotational position of the output member 14 can be further improved. In such a configuration, the magnetic body 18 is fixed so that the outermost portion in the radial direction is positioned at a portion where the tips of the pair of tongue pieces 145 are separated from each other. Therefore, since the thick wall portion is not formed on the outermost outer wall in the radial direction of the magnetic body 18, the outermost radial direction is exposed. Therefore, the size of the extending portion 143 in the radial direction can be made smaller than the configuration in which the magnetic body 18 is embedded in the extending portion 143 (the configuration shown in FIG. 4).

  Further, as shown in FIG. 6A, the magnetic body 18 is fixed so that a part thereof enters the recess 146 formed in the extending portion 143. Specifically, as shown in FIG. 6B in a state where the magnetic body 18 is removed from the output member 14, a protruding portion 147 is formed on the outer peripheral surface of the extending portion 143 so as to straddle the recess 146. The magnetic body 18 is fixed such that the end surface is sandwiched between the bottom surface 146a of the recess 146 and the protrusion 147. In this way, not only inadvertent dropping of the magnetic body 18 is prevented, but also the positional displacement of the output member 14 in the axial direction is prevented, so that the interval between the magnetic detection element 16 and the magnetic body 18 is reduced. Variability is suppressed.

  Here, as can be seen from FIG. 6B, a protrusion 147 a having a predetermined size is formed at the approximate center of the surface of the protrusion 147 that faces the bottom surface 146 a of the recess 146. Since the magnetic body 18 is mounted by crushing the protrusion 147a at the end face, the protrusion 147a works like a spring, and the sandwiching strength of the magnetic body 18 by the bottom surface 146a of the recess 146 and the protrusion 147 is increased. Thereby, the fall prevention performance of the magnetic body 18 further increases.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

  For example, in the above-described embodiment, it has been described that the magnetic body 18 is fixed to the output member 14, but conversely, that is, the magnetic detection element 16 is fixed to the output member 14, and the magnetic body 18 is positioned at a position opposite to the magnetic detection element 16. 18 may be provided.

  Moreover, in these embodiments, four magnetic body fixing holes 144 are provided on the outer peripheral surface of the output member 14, and the magnetic body 18 is selectively attached to one or two of them. However, for example, magnetic material fixing holes are provided at three locations on the outer peripheral surface of the output member (circumferential direction 0 ° (360 °), 120 °, 240 °), and magnetic material is selectively provided at one or two of them. It may be attached. In any case, the output member itself is provided with a plurality of magnetic substance fixing holes or magnetic detection element attachment portions on the outer peripheral surface thereof, and a magnetic substance or a magnetic detection element can be selectively attached to one or more of them. With this configuration, there is an advantage that the number of output members can be reduced because it is not necessary to produce various types of output members according to the usage mode of the valve and can be used interchangeably.

DESCRIPTION OF SYMBOLS 1 Geared motor 10 Motor 12 Tooth wheel train 14 Output member 141 Input part 142 Output part 143 Extension part 144 Magnetic body fixing hole (recessed part)
144b Bottom surface (contact surface)
16 Magnetic detection element 18 Magnetic body

Claims (10)

  A motor, an output member for transmitting the driving force of the motor through the toothed wheel train, an output member for outputting the transmitted driving force of the motor, a magnetic detection element for detecting a rotational position of the output member, and In a geared motor including a magnetic body that forms a pair with the magnetic detection element, the output member is input to the input unit to which the driving force of the motor transmitted to the tooth wheel train is input, and to the input unit. In addition, an output portion that outputs the driving force of the motor and an extending portion that protrudes radially outward from the input portion and the output portion are provided by integral molding, and the vicinity of the radially outer wall of the extending portion One of the magnetic detection element and the magnetic body is fixed to a geared motor.   The geared motor according to claim 1, wherein the input unit and the output unit are provided at positions that overlap each other in a radial direction of the output member.   The geared motor according to claim 2, wherein the output unit is provided on an axis of the input unit.   The geared motor according to any one of claims 1 to 3, wherein the extended portion is provided at a position overlapping the input portion or the output portion in the axial direction of the output member.   5. The geared motor according to claim 4, wherein the magnetic detection element or the magnetic body is provided at a position overlapping the input unit or the output unit in an axial direction of the output member.   In the axial direction of the output member, the output member has a hole portion opened to one side and a hole portion opened to the other, and the input portion is formed in the hole portion opened to the one side and the hole portion opened to the other side The output portion is formed, an extending portion is formed on a radially outer side of the hole portion opened to the one side or the hole portion opened to the other side, and the magnetic detection element or the magnetic body is an axis of the output member. The geared motor according to claim 5, wherein the geared motor is provided at a position overlapping with the one hole or the other hole in the direction.   The geared motor according to claim 6, wherein the hole portion that opens to the one side and the hole portion that opens to the other side are connected to each other and pass through the output member in the axial direction.   In the case where the magnetic detection element and the magnetic body are arranged so as to face each other in the axial direction, the extending portion is in contact with the axial line on which either the magnetic detection element or the magnetic body abuts. The geared motor according to any one of claims 1 to 7, wherein a recessed portion having a contact surface perpendicular to the surface is formed.   The geared motor according to claim 8, wherein the extending portion is formed of a resin, and the opening of the recess is sealed by heat sealing.   2. The extension portion is formed with a pair of tongue pieces on which either the magnetic detection element or the magnetic body protruding outward from the outer wall surface is held. The geared motor as described in any one of 1 to 9.

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