JP6057036B2 - Motor and encoder for motor - Google Patents

Description

  The disclosed embodiment relates to a motor and a motor encoder.

  Patent Document 1 describes a motor including a motor body, a rotating body, and a magnetic field sensor having a magnetic body having a large Barkhausen effect.

International Publication No. 2013/094042

  The magnetic field sensor may be affected by the leakage magnetic flux from the motor electromagnetic part or the like, but the above-described conventional technique has not been configured with special consideration for the leakage magnetic flux.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a motor and a motor encoder that can reduce the influence on a magnetic field sensor due to leakage magnetic flux from a motor electromagnetic part or an electromagnetic brake. And

  In order to solve the above problems, according to one aspect of the present invention, a motor including an encoder, the motor electromagnetic unit configured to rotate the motor shaft, and the motor shaft are braked. An electromagnetic brake configured, and the encoder includes a magnet supported to rotate with the motor shaft and a magnetic body having a large Barkhausen effect, and configured to detect a magnetic field of the magnet And a magnetic flux induction member for inducing the leakage flux so that a leakage flux from at least one of the motor electromagnetic unit and the electromagnetic brake to the magnetic field sensor is in a direction perpendicular to the length direction of the magnetic field sensor. And a motor is applied.

  According to another aspect of the present invention, a motor including an encoder, a motor electromagnetic unit configured to rotate a motor shaft, and an electromagnetic brake configured to brake the motor shaft The encoder includes a magnet supported to rotate with the motor shaft, and a magnetic field sensor configured to detect a magnetic field of the magnet, the magnetic body having a large Barkhausen effect. A motor having an encoder shaft made of a magnetic material that rotates with the motor shaft and is arranged to face the magnetic field sensor in a radial direction of a rotation locus circle of the magnet is applied.

  According to still another aspect of the present invention, a motor including an encoder, the motor electromagnetic unit configured to rotate the motor shaft, and the electromagnetic configured to brake the motor shaft. And a magnetic field sensor configured to detect a magnetic field of the magnet, wherein the encoder includes a magnet supported to rotate together with the motor shaft, and a magnetic body having a large Barkhausen effect. And arranged between the motor electromagnetic part or the electromagnetic brake and the encoder, and configured to generate a magnetic flux from the encoder side toward the motor electromagnetic part or the electromagnetic brake side on the axis of the motor shaft. And a motor having a coil applied thereto.

  According to still another aspect of the present invention, there is provided a motor encoder for use in a motor having a motor electromagnetic unit configured to rotate a motor shaft, and is supported so as to rotate together with the motor shaft. And a magnetic field sensor configured to detect a magnetic field of the magnet, an electromagnetic brake configured to perform braking of the motor shaft, and the motor electromagnetic unit A motor encoder having a magnetic flux guide member that induces the leakage magnetic flux so that the leakage magnetic flux from at least one of the magnetic field sensor to the magnetic field sensor is in a direction orthogonal to the length direction of the magnetic field sensor is applied.

  According to the motor and the like of the present invention, it is possible to reduce the influence on the magnetic field sensor due to the leakage magnetic flux from the motor electromagnetic part and the electromagnetic brake.

It is explanatory drawing for demonstrating an example of the outline of a structure of the servo system which concerns on one Embodiment. It is explanatory drawing for demonstrating an example of a structure of the servomotor which concerns on the same embodiment. It is explanatory drawing for demonstrating an example of a structure of the magnet which concerns on the embodiment, and a magnet fixing member. It is explanatory drawing for demonstrating an example of a structure of the magnetic field sensor and support | pillar member which concern on the embodiment. It is explanatory drawing for demonstrating an example of a structure of the board | substrate which concerns on the embodiment, a board | substrate fixing member, and an optical module. It is explanatory drawing for demonstrating an example of a structure of the control part which concerns on the same embodiment. It is explanatory drawing for demonstrating an example of a structure of the servomotor SM which concerns on the modification which arrange | positions a shield member between an electromagnetic brake and an encoder. It is explanatory drawing for demonstrating an example of a structure of the servomotor SM which concerns on the modification which arrange | positions a coil between an electromagnetic brake and an encoder.

  Hereinafter, an embodiment will be described with reference to the drawings. In the present specification and drawings, components having substantially the same function are represented by the same reference numerals in principle, and repeated description of these components will be omitted as appropriate.

<1. Servo system>
First, an example of a schematic configuration of a servo system according to the present embodiment will be described with reference to FIG. FIG. 1 is a schematic diagram illustrating an example of a schematic configuration of a servo system according to the present embodiment.

  As shown in FIG. 1, the servo system S includes a servo motor SM and a control device CT. The servo motor SM includes a motor electromagnetic unit M, an electromagnetic brake 200, and an encoder 100.

  Here, the configuration including the motor electromagnetic unit M alone, the motor electromagnetic unit M and the electromagnetic brake 200, or the configuration including the motor electromagnetic unit M and the encoder 100 may be referred to as a motor or a servo motor. However, in this specification, a configuration including the motor electromagnetic unit M, the electromagnetic brake 200, and the encoder 100 is referred to as a servo motor SM. That is, the servo motor SM corresponds to an example of a motor, and the encoder 100 used for the servo motor SM corresponds to an example of a motor encoder.

  In addition, for convenience of explanation, a case will be described below where the motor is a servo motor SM that is controlled to follow a target value such as position and speed and has an electromagnetic brake 200. It is not limited to the servo motor SM. For example, the motor is controlled to follow target values such as position and speed, but may be a servo motor that does not have an electromagnetic brake. Furthermore, the motor may be a motor used other than the servo system as long as the encoder is attached, such as when the output of the encoder is used only for display.

  In the servo motor SM, the motor electromagnetic part M, the electromagnetic brake 200, and the encoder 100 may be provided as separate bodies (separate products), but the motor electromagnetic part M is integrally provided with the electromagnetic brake 200. Alternatively, the encoder 100 may be integrally provided with the electromagnetic brake 200. When the motor electromagnetic part M is integrally provided with the electromagnetic brake 200, the configuration (product) may be referred to as a “motor with brake”. On the other hand, when the encoder 100 is integrally provided with the electromagnetic brake 200, the configuration (product) may be referred to as “encoder with brake”. In the servo motor SM, the motor electromagnetic unit M may be integrally provided with the electromagnetic brake 200 and the encoder 100. However, for convenience of explanation, a case where the motor electromagnetic unit M is integrally provided with the electromagnetic brake 200 will be described below.

  The motor electromagnetic unit M outputs a rotational force by rotating the motor shaft SH1 about its axis AX. In this specification, the rotational force output side of the motor electromagnetic unit M is referred to as “load side”, and the opposite side is referred to as “anti-load side”.

  The electromagnetic brake 200 brakes the motor shaft SH1. “Brake of motor shaft SH1” means that the motor shaft SH1 that is rotating inertial is stationary, or when a force (torque) is applied to the stationary motor shaft SH1 from the outside. This is to hold the motor shaft SH1 and maintain the stationary state of the motor shaft SH1. The electromagnetic brake 200 is disposed adjacent to the non-load side of the motor electromagnetic unit M.

  The electromagnetic brake 200 does not necessarily have to be disposed adjacent to the motor electromagnetic unit M, and may be disposed in the motor electromagnetic unit M via another configuration such as a speed reducer, a rotation direction changer, and an encoder. Good. Further, the electromagnetic brake 200 may not necessarily be disposed on the anti-load side of the motor electromagnetic unit M, and may be disposed on the load side of the motor electromagnetic unit M. However, for convenience of explanation, a case will be described below in which the electromagnetic brake 200 is disposed adjacent to the non-load side of the motor electromagnetic unit M.

  The encoder 100 includes an encoder shaft SH2 that rotates together with the motor shaft SH1 and is supported so as to have the same axis as the motor shaft SH1. Then, the encoder 100 detects the position of the motor electromagnetic unit M (also referred to as “rotation position” or “rotation angle”) by detecting the position of the encoder shaft SH2, and outputs position data representing the position. To do. The encoder 100 is disposed on the non-load side of the motor electromagnetic unit M. Therefore, in the present embodiment in which the electromagnetic brake 200 is disposed adjacent to the anti-load side of the motor electromagnetic unit M, the encoder 100 is disposed on the anti-load side of the electromagnetic brake 200.

  In addition to or in place of the position of the motor electromagnetic unit M, the encoder 100 may also include the speed (also referred to as “rotational speed” or “angular velocity”) and acceleration (“rotational acceleration” or “angular acceleration” of the motor electromagnetic unit M. Or at least one of them may be detected. In this case, the speed and acceleration can be detected by processing such as, for example, differentiating the position by 1st or 2nd order with respect to time or counting the detection signal for a predetermined time. However, for convenience of explanation, a case where the physical quantity detected by the encoder 100 is a position will be described below.

  In addition, the encoder 100 does not necessarily have to be disposed on the non-load side of the electromagnetic brake 200. In other words, when the electromagnetic brake 200 does not have to be disposed adjacent to the anti-load side of the motor electromagnetic unit M, the encoder 100 is configured so that the motor electromagnetic unit M and the electromagnetic brake 200 are on the anti-load side of the motor electromagnetic unit M. Between the two. Furthermore, the encoder 100 does not necessarily have to be disposed on the anti-load side of the motor electromagnetic unit M, and may be disposed on the load side of the motor electromagnetic unit M. However, for convenience of explanation, a case will be described below in which the encoder 100 is disposed on the anti-load side of the electromagnetic brake 200 disposed adjacent to the anti-load side of the motor electromagnetic unit M.

  The control device CT acquires position data from the encoder 100 and controls the operation of the motor electromagnetic unit M based on the position data. Specifically, the control device CT controls the operation of the motor electromagnetic unit M by controlling the current or voltage applied to the motor electromagnetic unit M based on the position data. Further, the control device CT obtains a host control signal from a host control device (not shown), and outputs a rotational force capable of realizing the position or the like represented by the host control signal from the motor shaft SH1. It is also possible to control the operation of the electromagnetic part M.

  Further, the control device CT controls the operation of the electromagnetic brake 200. Specifically, the control device CT controls the operation of the electromagnetic brake 200 by controlling energization to the electromagnetic brake 200.

<2. Servo motor>
Next, an example of the configuration of the servo motor SM will be described with reference to FIGS. 2, 3, 4, and 5. FIG. 2 is a sectional view taken along the axis AX direction of the servo motor SM. 3 is a cross-sectional view taken along the line BB in FIG. 4 is a cross-sectional view taken along a line CC in FIG. FIG. 5 is a cross-sectional view taken along the line AA in FIG. In FIG. 2 and FIG. 4, an example of the leakage magnetic flux is conceptually illustrated by a thick solid arrow.

  As shown in FIG. 2, the servo motor SM includes the motor electromagnetic unit M, the electromagnetic brake 200, and the encoder 100.

  Here, for convenience of description of the structure of each component of the servo motor SM, in the following, directions such as left and right are determined as follows and used appropriately. That is, in FIGS. 2 to 5, the anti-load side direction, that is, the Z-axis positive direction is defined as “right”, and the reverse load side direction, that is, the Z-axis negative direction is defined as “left”. However, the directions such as left and right vary depending on the installation mode of the servo motor SM and do not limit the positional relationship of each component of the servo motor SM. In addition, depending on the convenience of explanation, other directions may be used for the direction defined here, or directions other than the direction defined here may be used while being described as appropriate.

(2-1. Motor electromagnetic part)
As shown in FIG. 2, the motor electromagnetic unit M includes a stator 20 and a rotor 10 disposed on the inner peripheral side of the stator 20. That is, the motor electromagnetic part M is configured as a so-called “inner rotor type” in which the rotor 10 is disposed on the inner peripheral side of the stator 20.

  The rotor 10 is fixed to the outer periphery of the motor shaft SH1 so as to have the same axis as the motor shaft SH1. The rotor 10 includes a magnet (not shown) that is a permanent magnet, for example. That is, the rotor 10 is configured as a field magnet.

  The motor shaft SH1 is made of, for example, a magnetic material, and is supported rotatably around the axis AX by bearings 30 and 35 having outer rings fitted to the inner circumferences of the brackets 40 and 45.

  The stator 20 is supported by the brackets 40 and 45 disposed on the left side and the right side thereof so as to face the outer periphery of the rotor 10 via a magnetic gap in the radial direction. The stator 20 includes a stator core 22, a bobbin (also referred to as “insulator”) 24 attached to the stator core 22, a coil wire 26 wound around the bobbin 24, and end portions of the coil wire 26. And a wiring board 28 for wiring processing, and is integrally formed by the resin mold part 50. That is, the stator 20 is configured as an armature. The bobbin 24 is made of an insulating material (for example, resin) and electrically insulates the stator core 22 and the coil wire 26 from each other.

  In the motor electromagnetic part M having the above configuration, a magnetic field is generated inside the stator 20 by energizing the coil wire 26. Then, due to the interaction between the magnetic field inside the stator 20 and the magnetic field generated by the magnet of the rotor 10, the rotor 10 rotates about the axis AX relative to the stator 20, so that the motor shaft SH <b> 1 is rotated about the axis AX. Rotate around.

  The configuration of the motor electromagnetic unit M described above is merely an example, and a configuration other than the above may be used. For example, the motor electromagnetic unit M is not limited to the case where the rotor 10 is configured as a field and the stator 20 is configured as an armature, but the rotor 10 is configured as an armature and the stator 20 is configured as a field. May be. Further, for example, the motor electromagnetic unit M is not limited to being configured as an inner rotor type, and may be configured as a so-called “outer rotor type” in which a rotor is disposed on the outer peripheral side of the stator.

(2-2. Electromagnetic brake)
As shown in FIG. 2, the electromagnetic brake 200 includes a brake disk 202, a field core 204 that houses an exciting coil 210 and a spring (not shown), and an armature 206. Each component constituting the electromagnetic brake 200 such as the brake disc 202, the field core 204, and the armature 206 is accommodated in a housing 220.

  The housing 220 has a motor shaft SH1 inserted therethrough and is fixed to the right end of the bracket 45 of the motor electromagnetic unit M.

  The brake disc 202 is fixed to the outer periphery of the motor shaft SH1 so that the center of rotation coincides with the axis AX.

  The armature 206 is made of a magnetic material, and is disposed so as to be movable only in the left-right direction between the brake disk 202 and the field core 204 so as to face the field core 204 in the left-right direction.

  The spring exerts a biasing force that presses the armature 206 to the left.

  A friction material 214 is attached to the surface of the brake disk 202 that faces the armature 206.

  The electromagnetic brake 200 operates so as to brake the motor shaft SH1 in a non-energized state (non-excited state) in which the excitation coil 210 is not energized, and an energized state (excited state) in which the excitation coil 210 is energized. Then, the motor shaft SH1 is not braked and is configured as a “non-excitation operation type” electromagnetic brake.

  Hereinafter, an example of the operation of the electromagnetic brake 200 having the above configuration will be described.

  That is, in the non-excited state, the armature 206 moves to the left side by being pressed to the left side by the spring and contacts the friction material 214. As a result, the brake disc 202 is braked and the motor shaft SH1 is braked.

  On the other hand, in the excited state, the exciting coil 210 gives the armature 206 a magnetic attractive force to the right side. As a result, the armature 206 moves to the right against the biasing force of the spring and is separated from the friction material 214. As a result, the brake disc 202 is not braked and the motor shaft SH1 is not braked.

  Note that the configuration and operation of the electromagnetic brake 200 described above are merely examples, and configurations and operations other than those described above may be used. For example, the electromagnetic brake 200 is not limited to a non-excitation operation type electromagnetic brake. That is, the electromagnetic brake 200 operates to brake the motor shaft SH1 in the excited state, and does not brake the motor shaft SH1 in the non-excited state. Other types of electromagnetic brakes may be used as long as they can perform the above.

(2-3. Encoder)
As shown in FIGS. 2 to 5, the encoder 100 includes the encoder shaft SH <b> 2, a magnetic detection mechanism, an optical detection mechanism, and a control unit 150 (see FIG. 6 described later). And each component which comprises the encoder 100, such as these magnetic detection mechanisms, an optical detection mechanism, and the control part 150, is accommodated in the lidded cylindrical encoder cover 102, for example.

  The encoder cover 102 is made of a magnetic material and is fixed to the right end of the housing 220 of the electromagnetic brake 200.

  The encoder cover 102 does not necessarily need to be made of a magnetic material, and may be made of a nonmagnetic material. However, for convenience of explanation, a case where the encoder cover 102 is made of a magnetic material will be described below.

(2-3-1. Encoder shaft)
The encoder shaft SH2 is rotatably supported around the axis AX together with the motor shaft SH1 by bearings 104 and 106 having outer rings fitted to the inner periphery of the bracket 108. The encoder shaft SH2 is separate from the motor shaft SH1, and is connected to the right end portion 1R (corresponding to an example of an end portion) of the motor shaft SH1. Specifically, the right end portion 1R of the motor shaft SH1 is formed to have a smaller diameter than other portions, for example, by cutting, and the left end portion 2R1 of the encoder shaft SH2 is formed with a concave portion 2R1a that is recessed on the right side. . The encoder shaft SH2 is coupled to the right end 1R of the motor shaft SH1 by fitting the right end 1R and the recess 2R1a.

  The bracket 108 is connected to the housing 220 of the electromagnetic brake 200 via a support member (not shown).

  Further, the encoder shaft SH2 is made of a magnetic material, and opposes magnetic field sensors 120a, 120b, and 120c, which will be described later, in the radial direction of rotation locus circles Ra, Rb, Rc, and Rd of magnets 111a, 111b, 111c, and 111d, which will be described later. Are arranged as follows. Specifically, the right end 2R2 of the encoder shaft SH2 protrudes to the right from the magnetic field sensors 120a to 120c. As a result, the leakage magnetic flux from at least one of the motor electromagnetic part M and the electromagnetic brake 200 toward the encoder 100 is concentrated on the encoder shaft SH2, and a part of the magnetic flux of the leakage magnetic flux is transferred from the right end 2R2 of the encoder shaft SH2. It is possible to form so as to bypass the sensors 120a to 120c.

  Note that the connection mode between the right end 1R of the motor shaft SH1 and the encoder shaft SH2 is not limited to the connection by fitting the right end 1R and the recess 2R1a as described above, and other modes may be used. Good. Further, the encoder shaft SH2 is not limited to a case separate from the motor shaft SH1, and may be integrated with the motor shaft SH1. However, for convenience of explanation, a case where the encoder shaft SH2 is separate from the motor shaft SH1 will be described below. Further, the right end 2R2 of the encoder shaft SH2 does not necessarily protrude to the right of the magnetic field sensors 120a to 120c, and may be located at substantially the same position in the left-right direction as the magnetic field sensors 120a to 120c.

(2-3-2. Magnetic detection mechanism)
The magnetic detection mechanism is a mechanism for magnetically detecting the rotation state (for example, the rotation speed and the rotation direction) of the motor electromagnetic unit M. This magnetic detection mechanism includes four permanent magnets 111a, 111b, 111c, and 111d (hereinafter collectively referred to as “magnet 111” as appropriate) and three magnetic field sensors 120a, 120b, and 120c (hereinafter referred to as “magnetic field sensor 120 as appropriate”). Are collectively referred to as “.”.

  Magnets 111a to 111d are supported so as to rotate together with motor shaft SH1. Specifically, the encoder 100 is fixed to the outer periphery of the right end portion 2R2 of the encoder shaft SH2 so that it has the same axis as the motor shaft SH1 and the plate surface direction is perpendicular to the left-right direction. A plate-like magnet fixing member 112 is provided. The magnet fixing member 112 is made of, for example, a nonmagnetic material, but may be made of a magnetic material. The magnets 111a to 111d are flat magnets, fixed to the left surface of the magnet fixing member 112 (the surface facing the magnetic field sensors 120a to 120c in the left-right direction), and around the axis AX together with the magnet fixing member 112. Rotate. More specifically, the magnets 111a, 111b, 111c, and 111d have the same radius and circumference of their respective rotation locus circles Ra, Rb, Rc, and Rd (hereinafter collectively referred to as “rotation locus circle R” as appropriate). To be fixed. More specifically, the magnets 111 a to 111 d are, for example, equally spaced (90 ° intervals) in the circumferential direction of the rotation locus circle R (hereinafter, simply referred to as “circumferential direction”) with respect to the left surface of the magnet fixing member 112. ) Are fixed so as to be separated.

  The magnets 111a to 111d are magnetized in the left-right direction, and are arranged so that the left magnetic poles alternate in the circumferential direction. For example, the magnets 111a, 111b, 111c, and 111d are arranged so that the left magnetic poles are N poles, S poles, N poles, and S poles. In FIG. 1, the magnetic poles of the magnets 111a to 111d are not shown, and in FIG. 3, only the left magnetic poles of the magnets 111a to 111d are shown.

  Note that the number of magnets 111 is not limited to four, and may be other numbers. When the number of the magnets 111 is other than four, the number and arrangement of the magnetic field sensors 120 and the like can be changed as appropriate. However, for convenience of explanation, a case where the number of magnets 111 is four will be described below. The magnet 111 is not limited to a permanent magnet, and may be another magnet (for example, an electromagnet). The magnet 111 is not limited to a flat magnet, and may be another magnet (for example, a ring magnet (multipolar magnet) or an arc magnet). However, for convenience of explanation, a case where the magnet 111 is a permanent magnet and a flat magnet will be described below.

  The magnet 111 is not limited to being fixed to the magnet fixing member 112, and may be fixed to the encoder shaft SH2, a disk 130, a hub 131, and the like described later. When the magnet 111 is fixed to the encoder shaft SH2, the disk 130, the hub 131, etc., the magnet fixing member 112 can be omitted. However, for convenience of explanation, a case where the magnet 111 is fixed to the magnet fixing member 112 will be described below.

  Further, the magnet 111 is not limited to the case where the magnet 111 is disposed on the right side of the magnetic field sensor 120 so as to face the magnetic field sensor 120 in the left-right direction, and may be disposed on the left side of the magnetic field sensor 120. Alternatively, the magnet 111 may be disposed inside or outside the magnetic field sensor 120 so as to face the magnetic field sensor 120 in the radial direction. However, for convenience of explanation, a case will be described below in which the magnet 111 is disposed on the right side of the magnetic field sensor 120 so as to face the magnetic field sensor 120 in the left-right direction.

  The magnetic field sensors 120 a to 120 c include a magnetic body (also referred to as “magnetic element”) 121 having a large Barkhausen effect, and a coil 122 wound around the magnetic body 121.

  Each of the magnetic field sensors 120a to 120c has a length direction (specifically, a length direction of the magnetic body 121) parallel to a tangential direction of the rotation locus circle R, and magnets 111a to 111d in the left-right direction (described later). It is fixed to the bracket 108 so as to be able to face each other (via the first magnetic member and the second magnetic member). Specifically, the magnetic field sensors 120a to 120c include the shortest distance between one end in the length direction of the magnetic body 121 and the axis AX, and the distance between the other end in the length direction of the magnetic body 121 and the axis AX. The shortest distance is equal to each other. More specifically, in the magnetic field sensors 120a to 120c, the shortest distance between the central portion in the length direction of each magnetic body 121 and the axis AX is equal to each other, and is, for example, equidistant (120 ° intervals) in the circumferential direction. Is arranged around the encoder shaft SH2 so as to be separated from each other. That is, the magnetic field sensors 120a to 120c are arranged around the encoder shaft SH2 so as to have a substantially triangular shape when viewed from the left-right direction.

  And the magnetic field sensors 120a-120c can detect the magnetic field by the magnets 111a-111d.

  Here, the “large Barkhausen effect” is a phenomenon in which the magnetization direction of the magnetic substance 121 is rapidly reversed when the strength of the applied external magnetic field exceeds a certain intensity, and is also referred to as a large Barkhausen jump.

  The magnetic body 121 is not particularly limited as long as it has a large Barkhausen effect. For example, a wire-shaped magnetic body (for example, a composite magnetic wire, a Wiegand wire, an amorphous wire, etc.), a rod-shaped magnetic body A plate-like magnetic body or the like can be used. However, for convenience of explanation, a case where the magnetic body 121 is a composite magnetic wire will be described below.

  The composite magnetic wire has a magnetic property that its outer peripheral part changes its magnetization direction by applying a relatively small external magnetic field, but its central part has a magnetic characteristic that the magnetization direction does not change unless a relatively large external magnetic field is applied. An anisotropic composite magnetic material.

  That is, when a relatively large external magnetic field sufficient to reverse the magnetization direction of the center portion of the composite magnetic wire is applied in one direction parallel to the length direction of the composite magnetic wire, the magnetization direction of the center portion of the composite magnetic wire And the magnetization direction of the outer peripheral portion are aligned in the same direction. After that, when a relatively small external magnetic field that can reverse only the magnetization direction of the outer peripheral portion of the composite magnetic wire is applied in another direction opposite to the one direction, the magnetization direction of the center portion of the composite magnetic wire changes. Without reversing, only the magnetization direction of the outer periphery is reversed. As a result, the magnetic direction of the composite magnetic wire is different between the central portion and the outer peripheral portion, and this state is maintained even when the external magnetic field is removed.

  Here, for example, an external magnetic field is applied to the composite magnetic wire in a state where the central portion is magnetized in the one direction and the outer peripheral portion is magnetized in the other direction. At this time, the strength of the external magnetic field is initially reduced and then gradually increased. Then, when the intensity of the external magnetic field exceeds a certain intensity, a large Barkhausen effect occurs, and the magnetization direction of the outer peripheral portion of the composite magnetic wire is rapidly reversed from the other direction to the one direction. Then, a pulse signal that rises sharply in the positive direction, for example, is output from the coil wound around the composite magnetic wire by the electromotive force generated by the rapid reversal of the magnetization direction of the composite magnetic wire.

  Further, for example, an external magnetic field is applied in the other direction to the composite magnetic wire in which both the central portion and the outer peripheral portion are magnetized in the one direction. Also at this time, the strength of the external magnetic field is initially reduced and then gradually increased. Then, when the intensity of the external magnetic field exceeds a certain level, a large Barkhausen effect occurs, and the magnetization direction of the outer peripheral portion of the composite magnetic wire is rapidly reversed from the one direction to the other direction. Then, a pulse signal that rises sharply in the negative direction, for example, is output from the coil wound around the composite magnetic wire by the electromotive force generated by the rapid reversal of the magnetization direction of the composite magnetic wire.

  In the magnetic field sensors 120a to 120c using the composite magnetic wires as described above as the magnetic body 121, a pulse is applied from the coil 122 when an external magnetic field is applied to the magnetic body 121 and the magnetization direction of the outer peripheral portion of the magnetic body 121 is reversed. A signal is output.

  In the encoder 100, a magnetic field corresponding to an external magnetic field applied to the magnetic body 121 is a magnetic field generated by two magnets 111 and 111 adjacent in the circumferential direction among the four magnets 111a to 111d, that is, the magnets 111a and 111a. The magnetic field by 111b, the magnetic field by magnets 111b and 111c, the magnetic field by magnets 111c and 111d, and the magnetic field by magnets 111d and 111a. These four magnetic fields are not large magnetic fields that can change the magnetization directions of both the central portion and the outer peripheral portion of the magnetic body 121, but can change only the magnetization directions of the outer peripheral portion of the magnetic body 121. The magnetic field.

  That is, when the magnets 111a to 111d rotate together with the motor shaft SH1, the magnetic field (magnetic field direction) applied to the magnetic body 121 of the magnetic field sensors 120a to 120c changes. As a result, in the magnetic field sensors 120 a to 120 c, the magnetization direction of the outer periphery of the magnetic body 121 is reversed, and a pulse signal is output from the coil 122. At this time, the magnetic field sensors 120a to 120c have a characteristic that they operate by the magnetic energy of each longitudinal component, and the magnetic field in the direction orthogonal to the longitudinal direction is directed to the magnetic field sensors 120a to 120c regardless of the magnetic field strength. There is almost no influence.

  In the encoder 100, as described above, the magnets 111a to 111d are arranged at 90 ° intervals in the circumferential direction, and the magnetic field sensors 120a to 120c are arranged at 120 ° intervals in the circumferential direction. Therefore, the timing at which a pulse signal is output from each coil 122 of the magnetic field sensors 120a to 120c does not overlap while the motor shaft SH1 rotates. And the control part 150 can detect the rotation state of the motor electromagnetic part M by performing a predetermined | prescribed process using the pulse signal output at a different timing from each coil 122 of the magnetic field sensors 120a-120c. Details will be described later).

  Note that the configuration and operation of the magnetic field sensor 120 described above are merely examples, and configurations and operations other than those described above may be used. For example, the arrangement shape of the magnetic field sensors 120a to 120c is not limited to a substantially triangular shape when viewed from the left-right direction, and may be another shape. Further, the number of magnetic field sensors 120 is not limited to three, but may be other numbers. When the number of magnetic field sensors 120 is other than three, the number and arrangement of the magnets 111 and the like can be changed as appropriate. However, for convenience of explanation, a case where the number of the magnetic field sensors 120 is three will be described below.

  In addition, each of the magnetic field sensors 120a to 120c has a portion facing the magnets 111a to 111d on one side in the length direction and a portion facing the magnets 111a to 111d on the other side in the length direction. Two magnetic members (both not shown) are covered. The first and second magnetic members corresponding to each of the magnetic field sensors 120 a to 120 c are arranged via a gap at the center in the longitudinal direction of the corresponding magnetic field sensor 120 and are fixed to the bracket 108. The first and second magnetic members corresponding to each of the magnetic field sensors 120a to 120c can induce a magnetic field applied to the corresponding magnetic field sensor 120 by the magnets 111a to 111d to form a predetermined magnetic path. It is.

  Note that the first and second magnetic members are omitted when it is possible to prevent a difficult change in the magnetization direction of the magnetic body 121 of the magnetic field sensor 120 without using the magnetic field induction function of the first and second magnetic members, for example. Is possible.

(2-3-3. Optical detection mechanism, substrate fixing member, support member)
The optical detection mechanism is a mechanism for optically detecting the position of the motor electromagnetic unit M. The optical detection mechanism includes a disk 130 that is an example of a measurement target that optically measures the position of the encoder shaft SH2, and an optical module 135.

  The disk 130 is connected via a hub 131 to a portion on the right side of the magnet fixing member 112 of the right end 2R2 of the encoder shaft SH2 so that the rotation center thereof coincides with the axis AX.

  The hub 131 is fixed to the right end of the encoder shaft SH2, for example, with a bolt 132. The hub 131 is preferably made of a magnetic material.

  On the right surface of the disk 130 (the surface on the side facing the optical module 135 in the left-right direction), there is one track (not shown) in which a plurality of reflective slits (not shown) are arranged along the circumferential direction. It is formed as described above. The reflection slit reflects light emitted from a light source 136 described later. As an arrangement pattern of the reflection slits in the track, for example, an “incremental pattern” in which the reflection slits are regularly repeated at a predetermined pitch, or the position and ratio of the reflection slits are uniquely determined within one rotation of the disk 130. Pattern "etc. are mentioned, It does not specifically limit.

  Further, on the right side of the right end 2R2 of the encoder shaft SH2 (on the side opposite to the motor shaft SH1 in the left-right direction), that is, on the right side of the disk 130, for example, a disk-shaped substrate 140 provided with electronic components (not shown) and For example, a disk-shaped substrate fixing member 145 is disposed.

  The substrate fixing member 145 is made of a magnetic material, and is arranged so that the plate surface direction is perpendicular to the left-right direction. That is, the substrate fixing member 145 corresponds to an example of a magnetic plate member. The board 140 is fixed to the right surface of the board fixing member 145 by, for example, a bolt 142 so as to be arranged on the left side of the board 140 (on the encoder shaft SH2 side in the left-right direction).

  The bolts 142 are arranged at a plurality of locations (for example, three locations) at regular intervals, for example, in the circumferential direction of the substrate 140.

  Specifically, the substrate fixing member 145 has, for example, an opening 145a that is a substantially circular hole centered on the center of the substrate fixing member 145, and the optical module 135 is formed on one surface of the substrate 140. is set up. Then, on the right surface of the substrate fixing member 145, the substrate 140 is the left surface (the surface on the disk 130 side) where the optical module 135 is installed, and the optical module 135 (specifically, at least a light source 136 and a light receiving array described later). ) Is fixed at the opening 145a. By fixing the substrate 140 to the right surface of the substrate fixing member 145 in this manner, the optical module 135 installed on the substrate 140 is exposed to the left side (the disk 130 side).

  The optical module 135 is installed on the left surface of the substrate 140 so as to be parallel to the disk 130 and to face a part of the track. A light source 136 is provided on the left surface of the optical module 135, and one or more light receiving arrays (not shown) in which a plurality of light receiving elements are arranged along the circumferential direction of the disk 130 are provided. The light source 136 is composed of, for example, an LED or the like, and emits light to a part of the track that passes through the facing position. The light receiving element is composed of, for example, a photodiode, and receives light reflected from the reflection slit of the track that is emitted from the light source 136 and passes through a facing position, and outputs a light reception signal. The control unit 150 can detect the position of the motor electromagnetic unit M (details will be described later) by performing a predetermined process using the light reception signal output from the light receiving element of the light receiving array.

  The substrate fixing member 145 is fixed to the bracket 108 while being supported by three columnar column members 147a, 147b, and 147c (hereinafter collectively referred to as “column members 147” as appropriate).

  The column members 147a to 147c are fixed by, for example, bolts 149 so as to stand between the board fixing member 145 and the bracket 108. These strut members 147a to 147c are arranged on the outer peripheral side of the magnetic field sensors 120a to 120c in the radial direction, for example, at equal intervals (120 ° intervals) in the circumferential direction. Specifically, the support members 147a, 147b, and 147c are made of a magnetic material, and are arranged on the outer peripheral side of the lengthwise center of each of the magnetic field sensors 120a, 120b, and 120c in the radial direction. The support members 147a to 147c are arranged such that the leakage magnetic flux from at least one of the motor electromagnetic unit M and the electromagnetic brake 200 to the magnetic field sensors 120a to 120c is in a direction orthogonal to the length direction of the magnetic field sensors 120a to 120c. It is possible to induce the leakage magnetic flux. That is, the support members 147a to 147c correspond to an example of a magnetic member and also an example of a magnetic flux guide member.

  The disk 130 is not limited to being connected to the encoder shaft SH2 via the hub 131, and may be directly fixed to the encoder shaft SH2 without the hub 131. Further, the measurement target is not limited to the disk 130, and may be another member such as the right end surface of the encoder shaft SH2. However, for convenience of explanation, a case where the measurement target is the disk 130 will be described below. Further, the encoder 100 is not limited to a case where a so-called “reflection type” optical detection mechanism is provided, and may include a so-called “transmission type” optical detection mechanism. Further, the encoder 100 does not necessarily include an optical detection mechanism. However, for convenience of explanation, a case where the encoder 100 includes a reflective optical detection mechanism will be described below.

  In the above, the right end portion 2R2 of the encoder shaft SH2 is not limited to the case where the encoder shaft SH2 is positioned on the left side of the substrate 140, and the encoder shaft SH2 may be positioned on the right side of the substrate 140 by passing through the substrate 140. Good. However, for convenience of explanation, a case where the right end 2R2 of the encoder shaft SH2 is located on the left side of the substrate 140 will be described.

  The substrate fixing member 145 is not limited to the case where the opening 145a that is a substantially circular hole centered on the center thereof is provided, and may have an opening of another shape. For example, the substrate fixing member 145 may include an opening formed so as to be cut out in a substantially rectangular shape from the edge to the center. Further, the substrate fixing member 145 is not limited to being disposed on the left side of the substrate 140, and may be disposed on the right side of the substrate 140. When the substrate fixing member 145 is disposed on the right side of the substrate 140, the substrate fixing member 145 having no opening can be used. Further, the magnetic plate member is not limited to the substrate fixing member 145, and may be a substrate fixing member as long as it is a magnetic plate member arranged on the right side of the encoder shaft SH2 and having a plate surface direction perpendicular to the left-right direction. Magnetic plate members other than 145 may be used. For example, when a magnetic plate member is installed on the right side of the disk 130 separately from the substrate fixing member 145, the substrate fixing member 145 may be made of a nonmagnetic material. Further, for example, when the substrate fixing member 145 is not installed, a magnetic plate member may be installed on the right side of the disk 130. Furthermore, the magnetic plate member does not necessarily have to be installed.

  The number of support members 147 is not limited to three, and can be changed as appropriate according to the number of magnetic field sensors 120. Moreover, the shape of the support | pillar member 147 is not limited to a column shape, Other shapes (for example, square column shape etc.) may be sufficient. Further, the magnetic member is not limited to the support member 147, and any magnetic member other than the support member 147 may be used as long as it is a magnetic member disposed on the outer peripheral side of the central portion in the length direction of the magnetic field sensor 120 in the radial direction. May be used. For example, in the case where a magnetic member is installed separately from the support member 147 on the outer peripheral side of the central portion in the length direction of the magnetic field sensor 120 in the radial direction, the support member 147 may be made of a nonmagnetic material. Further, for example, when the support member 147 is not installed, a magnetic member may be installed on the outer peripheral side of the central portion in the length direction of the magnetic field sensor 120 in the radial direction. Further, the magnetic flux guiding member is not limited to the magnetic plate member, and the direction in which the leakage magnetic flux from at least one of the motor electromagnetic part M and the electromagnetic brake 200 to the magnetic field sensor 120 is orthogonal to the length direction of the magnetic field sensor 120. Any member other than the magnetic plate member may be used as long as it is a member capable of inducing the leakage magnetic flux.

  In this embodiment, the encoder 100 is provided with a magnetic flux guiding member (the support member 147 in the above example) (hereinafter referred to as “first method” as appropriate), the encoder shaft SH2 is made of a magnetic material, and A method of arranging the magnetic field sensor 120 so as to face the magnetic field sensor 120 in the radial direction (hereinafter, referred to as “second method” as appropriate) is used together to reduce the influence of the leakage magnetic flux on the magnetic field sensor 120 as described below. The case where the effect is obtained is described. However, the first method and the second method do not necessarily need to be used together. If either one of the first method and the second method is employed, the magnetic field sensor 120 caused by the leakage magnetic flux is applied. An effect of reducing the influence can be obtained.

(2-3-4. Control unit)
The control unit 150 generates position data based on at least the light reception signal from the light receiving element of the light receiving array at the timing of generating the position data, and outputs the position data to the control device CT.

  Hereinafter, an example in which an example of the configuration of the control unit 150 is implemented more specifically with functional blocks will be described with reference to FIG. FIG. 6 is a functional block diagram illustrating an example of the configuration of the control unit 150.

  As illustrated in FIG. 6, the control unit 150 includes a rotation state detection unit 151, a position detection unit 156, and a position data generation unit 157. Each functional unit of the control unit 150 can be implemented by a program executed by a CPU (not shown) provided in the encoder 100 or a control device (not shown) provided in the encoder 100. The control device is configured by a dedicated integrated circuit or other electrical circuit constructed for a specific application such as ASIC or FPGA.

  The rotation state detection unit 151 detects the rotation state of the encoder shaft SH2 based on the voltage generated using the pulse signals output from the magnetic field sensors 120a to 120c even when the power supply voltage is not supplied from the external power supply. Is possible. The rotation state detection unit 151 includes a power supply switching unit 152, a waveform shaping unit 153, a multi-rotation detection unit 154, and a multi-rotation recording unit 155.

  When a power supply voltage is supplied from an external power supply, the power supply switching unit 152 supplies the power supply voltage to the waveform shaping unit 153, the multi-rotation detection unit 154, and the multi-rotation recording unit 155. On the other hand, when the power supply voltage is not supplied from the external power supply, the power supply switching unit 152 generates a voltage generated by using the pulse signals output from the magnetic field sensors 120a to 120c, the waveform shaping unit 153, the multi-rotation detection unit 154, and the The rotation recording unit 155 is supplied.

  Here, the pulse signals output from the magnetic field sensors 120a to 120c include a pulse signal that rises in the positive direction and a pulse signal that rises in the negative direction. The power supply switching unit 152 generates a voltage using a pulse signal that rises in the positive direction among these pulse signals, and supplies this voltage to the waveform shaping unit 153, the multi-rotation detection unit 154, and the multi-rotation recording unit 155. . When a full-wave rectifier or the like is used, a pulse signal that rises in the negative direction and is output from the magnetic field sensors 120a to 120c can be used for voltage generation.

  The waveform shaping unit 153 selects a pulse signal that rises in the positive direction from the pulse signals output from the magnetic field sensors 120a to 120c, shapes the waveform of the selected pulse signal so as to be a rectangular wave, and shapes the waveform. The pulse signal is output to the multi-rotation detection unit 154.

  The multi-rotation detection unit 154 detects the rotation of the encoder shaft SH2 based on the pulse signal output from the waveform shaping unit 153. Specifically, the multi-rotation detection unit 154 determines whether the detection pulse output from the waveform shaping unit 153 is a pulse signal corresponding to any one of the magnetic field sensors 120a to 120c, and determines the result. Records in the multi-rotation recording unit 155. For example, the multi-rotation detection unit 154 receives data “00” in the case of a pulse signal corresponding to the magnetic field sensor 120a, and data “01” in the case of a pulse signal corresponding to the magnetic field sensor 120b. In the case of a pulse signal corresponding to, data “10” is recorded in the multi-rotation recording unit 155. The multi-rotation detection unit 154 detects the rotation of the encoder shaft SH2 based on the data recorded in the multi-rotation recording unit 155, and outputs a multi-rotation signal to the position data generation unit 157.

  As described above, since the rotation state detection unit 151 can self-generate power consumption even when a power supply voltage is not supplied from an external power supply, it is possible to omit a backup power supply (for example, a battery). .

  The position detection unit 156 detects the position of the motor electromagnetic unit M based on the light reception signal output from the light receiving element of the light receiving array, and outputs the position signal to the position data generation unit 157.

  The position data generation unit 157 acquires the position signal output from the position detection unit 156 and the multi-rotation signal output from the multi-rotation detection unit 154. Then, the position data generation unit 157 generates position data based on the acquired position signal and multi-rotation signal, and outputs the generated position data to the control device CT.

  At this time, the position data generation unit 157 can also generate the position data based only on the position signal output from the position detection unit 156 when the power supply voltage is supplied from the external power supply. On the other hand, when the supply of the power supply voltage from the external power supply is started after the power supply voltage from the external power supply is stopped, the position data generation unit 157 generates the position signal output from the position detection unit 156 and the multiple rotations. Based on the multi-rotation signal output from the detection unit 154, position data is generated.

  Note that the above-described separation of the components of the control unit 150 illustrated in FIG. 6 is merely an example, and other than the above may be employed.

  Note that the configuration and operation of the encoder 100 described above are merely examples, and configurations and operations other than those described above may be used.

<3. Examples of effects according to this embodiment>
The encoder 100 according to the present embodiment described above includes magnets 111a to 111c, magnetic field sensors 120a to 120c, and a magnetic flux guiding member (the column members 147a to 147c in the above example). The magnetic field sensors 120a to 120c operate by the magnetic energy of the longitudinal component, and the magnetic field in the direction orthogonal to the longitudinal direction has little influence on the magnetic field sensors 120a to 120c regardless of the magnetic field strength. In the magnetic flux guiding member (the column members 147a to 147c in the above example), the leakage magnetic flux from at least one of the motor electromagnetic part M and the electromagnetic brake 200 to the magnetic field sensors 120a to 120c is orthogonal to the length direction of the magnetic field sensors 120a to 120c. The leakage magnetic flux is induced so as to be in the direction. Thereby, the influence on the magnetic field sensors 120a-120c by the leakage magnetic flux from the motor electromagnetic part M or the electromagnetic brake 200 can be reduced. As a result, the detection accuracy of the encoder 100 can be improved and the motor characteristics can be improved.

  In addition, for example, when the leakage flux spreads radially outward from the center (motor shaft SH1 or bearings 104, 106), the longitudinal component of the leakage flux is one side in the length direction of the magnetic field sensors 120a to 120c. The other direction is the opposite direction, and the magnetic field strength acting on the magnetic field sensors 120a to 120c is unbalanced in the length direction. In this case, since the manifestation mechanism of the large Barkhausen effect changes, the output waveform may be disturbed. Therefore, in the present embodiment, when the magnetic member (the column members 147a to 147c in the above example) as the magnetic flux guiding member is disposed on the outer peripheral side of the center portion in the length direction of the magnetic field sensors 120a to 120c, the following is performed. Effects are obtained. That is, according to the above configuration, when the leakage magnetic flux spreads outward from the center in the radial direction, it can be guided to pass through the central portions of the magnetic field sensors 120a to 120c. Accordingly, the leakage magnetic flux can be set in a direction substantially orthogonal to the length direction of the magnetic field sensors 120a to 120c, so that the unbalance of the magnetic field strength can be prevented and the influence of the leakage magnetic flux can be reduced.

  Moreover, in this embodiment, when the encoder shaft SH2 is made of a magnetic material and arranged so as to face the magnetic field sensors 120a to 120c in the radial direction, the following effects are obtained. That is, with the above configuration, the leakage magnetic flux from at least one of the motor electromagnetic part M and the electromagnetic brake 200 toward the encoder 100 is concentrated on the encoder shaft SH2, and the magnetic path of the leakage magnetic flux is changed from the right end 2R2 of the encoder shaft SH2 to the magnetic field. The sensors 120a to 120c can be formed to bypass the sensor 120a to 120c. Thereby, the influence on the magnetic field sensors 120a to 120c due to the leakage magnetic flux can be reduced. In addition, since it is not necessary to configure the motor shaft SH1 with a nonmagnetic material (for example, SUS) or reduce the magnetic flux leakage to the encoder 100 side with a magnetic material (for example, iron) and a nonmagnetic material, Cost can be greatly reduced.

  In the present embodiment, when the encoder shaft SH2 is separated from the motor shaft SH1, the following effects are obtained. That is, the encoder 100 can be unitized with the above configuration. Further, by attaching the unitized encoder 100 to the existing motor with brake, it is possible to easily realize the motor with encoder capable of reducing the influence of leakage magnetic flux.

  Further, in this embodiment, when a magnetic plate member (substrate fixing member 145 in the above example) having a plate surface direction in a direction perpendicular to the left-right direction is provided on the right side of the encoder shaft SH2, the following is performed. Get the effect. That is, with the above configuration, the magnetic flux leakage from the motor electromagnetic part M and the electromagnetic brake 200 is directed radially outward from the right end 2R2 of the encoder shaft SH2 via the magnetic plate member (the substrate fixing member 145 in the above example). Can be guided radially. As a result, it is possible to improve the reliability of forming the magnetic path of the leakage magnetic flux so as to bypass the magnetic field sensors 120a to 120c.

  In the present embodiment, when the magnetic plate member is the substrate fixing member 145, the following effects are obtained. That is, with the above configuration, the magnetic plate member and the substrate fixing member can be used together, so that the number of parts can be reduced. Therefore, the servo motor SM can be downsized and the cost can be reduced. Moreover, when the board | substrate fixing member 145 is arrange | positioned on the left side of the board | substrate 140, an electronic component can be protected from a leakage magnetic flux etc., and the disturbance noise with respect to an electronic component can be reduced.

  Moreover, in this embodiment, when the magnetic flux induction member is the support members 147a to 147c, the following effects are obtained. That is, with the above configuration, the magnetic flux guiding member and the support member can be used together, so that the number of parts can be reduced. Therefore, the servo motor SM can be downsized and the cost can be reduced.

  Also in the optical encoder, there is a possibility that an induced electromotive force is generated in the electronic circuit due to the leakage magnetic flux and the detection accuracy is lowered. Therefore, in the present embodiment, when the encoder 100 is an optical encoder and the substrate fixing member 145 has an opening 145a that exposes the light receiving element to the left side, the following effects are obtained. That is, the above configuration does not hinder the function as an optical encoder. Furthermore, the magnetic path of the leakage magnetic flux can be formed so as to avoid the electronic circuit by the opening 145a. Therefore, the influence can be reduced and the detection accuracy of the encoder 100 can be increased.

  In this embodiment, when the encoder cover 102 is made of a magnetic material, the following effects are obtained. That is, with the above configuration, the magnetic path of the leakage magnetic flux induced by the magnetic flux guiding member (the column members 147a to 147c in the above example) can be formed on the outer periphery of the encoder 100. In addition, the encoder cover 102 serves as a shield against an external disturbance magnetic field, and the influence of the disturbance magnetic field on the magnetic field sensors 120a to 120c can be reduced. Furthermore, the influence on external electronic components can be reduced.

  Further, in the present embodiment, when the encoder 100 is configured to integrally include the electromagnetic brake 200, an encoder with a brake that is integrally provided with the electromagnetic brake 200 can be configured. Further, in the encoder with brake, the electromagnetic brake 200 and the magnetic field sensors 120a to 120c are arranged closer to each other, so that the magnetic field sensors 120a to 120c are more easily affected by the leakage magnetic flux from the electromagnetic brake 200. Therefore, it is more effective to apply the configuration.

<4. Modified example>
The embodiment has been described in detail with reference to the accompanying drawings. However, the scope of the technical idea described in the claims is not limited to the embodiment described above. It is obvious that a person having ordinary knowledge in the technical field to which the embodiment belongs can make various changes, corrections, combinations, and the like within the scope of the technical idea. Accordingly, the technology after these changes, corrections, combinations, and the like are naturally within the scope of the technical idea. Hereinafter, such modifications will be sequentially described.

(4-1. When a shield member is placed between the electromagnetic brake and encoder)
Hereinafter, an example of the configuration of the servo motor SM according to the present modification will be described with reference to FIG. FIG. 7 is a diagram corresponding to FIG.

  As shown in FIG. 7, the servo motor SM according to this modification is configured with a magnetic material between the electromagnetic brake 200 and the encoder 100, that is, between the housing 220 </ b> A of the electromagnetic brake 200 and the bracket 108 of the encoder 100. For example, an annular shield member 300 is disposed. An insertion hole 301 is formed in the shield member 300. The shield member 300 is fixed to at least one of the housing 220A and the bracket 108 via a support member (not shown) while inserting the encoder shaft SH2 through the insertion hole 301. By arranging the shield member 300 as described above, the magnetic path of the leakage magnetic flux that leaks from the electromagnetic brake 200 to the encoder 100 side without passing through the motor shaft SH1 or the encoder shaft SH2 is provided between the electromagnetic brake 200 and the encoder 100. It is possible to form.

  Note that the motor shaft SH <b> 1 may be inserted through the insertion hole 301 of the shield member 300. For example, when the encoder 100 is disposed adjacent to the motor electromagnetic unit M, the shield member 300 may be disposed between the motor electromagnetic unit M and the encoder 100.

  In the modification described above, the same effects as those of the above embodiment can be obtained. Furthermore, in this modification, by arranging the shield member 300 between the electromagnetic brake 200 and the encoder 100, the shield member 300 causes the encoder 100 side to move from the electromagnetic brake 200 without passing through the motor shaft SH1 or the encoder shaft SH2. Leakage magnetic flux leaking into can be cut off. Therefore, the influence on the magnetic field sensors 120a to 120c due to the leakage magnetic flux from the electromagnetic brake 200 can be further reduced.

(4-2. When placing a coil between the electromagnetic brake and encoder)
Hereinafter, an example of the configuration of the servo motor SM according to the present modification will be described with reference to FIG. FIG. 8 is a diagram corresponding to FIG. In FIG. 8, an example of the leakage magnetic flux is conceptually illustrated by a thick solid arrow, and the magnetic flux generated by the coil is conceptually illustrated by a thick broken arrow.

  As shown in FIG. 8, in the servo motor SM according to this modification, the coil 400 is disposed between the electromagnetic brake 200 and the encoder 100, that is, between the housing 220A of the electromagnetic brake 200 and the bracket 108 of the encoder 100. ing. The coil 400 is a magnetic flux on the axis AX of the motor shaft SH1 from the encoder 100 side toward the electromagnetic brake 200 side, that is, a magnetic flux in a direction opposite to the leakage magnetic flux from at least one of the motor electromagnetic part M and the electromagnetic brake 200 toward the encoder 100 side. Is generated. By arranging the coil 400 as described above, it is possible to cancel the magnetic flux generated by the coil 400 and the leakage magnetic flux from at least one of the motor electromagnetic part M and the electromagnetic brake 200 toward the encoder 100.

  For example, when the encoder 100 is disposed adjacent to the motor electromagnetic unit M, the coil 400 may be disposed between the motor electromagnetic unit M and the encoder 100. When the coil 400 is disposed between the motor electromagnetic unit M and the encoder 100, the coil 400 generates a magnetic flux from the encoder 100 side toward the motor electromagnetic unit M side on the axis AX of the motor shaft SH1.

  In this modification, in addition to the first method and the second method described in the above embodiment, a method of arranging the coil 400 between the electromagnetic brake 200 and the encoder 100 (hereinafter referred to as “third method” as appropriate). In the following, a case where the effect of further reducing the influence on the magnetic field sensor 120 due to the leakage magnetic flux as described below is described will be described. However, the third method may not necessarily be used in combination with the first method and the second method, and may be employed alone or in combination with either the first method or the second method. May be. Even in these cases, it is possible to obtain an effect of reducing the influence of the leakage magnetic flux on the magnetic field sensor 120.

  In the modification described above, the same effects as those of the above embodiment can be obtained. Furthermore, in this modification, by disposing the coil 400 between the electromagnetic brake 200 and the encoder 100, magnetic flux generated by the coil 400 and leakage from the motor electromagnetic part M or the electromagnetic brake 200 toward the encoder 100 side. The magnetic flux cancels each other, and the influence of the leakage magnetic flux on the magnetic field sensors 120a to 120c can be further reduced.

(4-3. Others)
In the above, the servo motor SM provided with the electromagnetic brake 200 has been described as an example. However, the first method, the second method, and the third method described above are also applied to a servo motor that does not include the electromagnetic brake 200. Can be applied, and the same effects as those of the above-described embodiments and modifications can be obtained.

  In the above description, when there is a description such as “vertical”, “orthogonal”, “parallel”, “center”, etc., the description is not strict. That is, “vertical”, “orthogonal”, “parallel”, “center”, and the like allow tolerances and errors in design, and “substantially vertical” “substantially orthogonal” “substantially parallel”. It means “substantially central” or the like.

  In addition, in the above description, when there are descriptions such as “same”, “equal”, “match”, “different”, etc., the dimensions and size in appearance are not strict meanings. That is, these “identical”, “equal”, “match”, “different”, etc., allow tolerances and errors in design, and “substantially the same” “substantially equal” “substantially coincide” It means “substantially different”.

100 Encoder (Example of motor encoder)
102 Encoder cover 111a to 111c Magnet 120a to 120c Magnetic field sensor 121 Magnetic body 130 Disc 136 Light source 140 Substrate 145 Substrate fixing member (an example of magnetic plate member)
145a opening 147a-147c support | pillar member (an example of a magnetic member, an example of a magnetic flux guide member)
1R right end (example of end)
DESCRIPTION OF SYMBOLS 200 Electromagnetic brake 300 Shield member 301 Insertion hole 400 Coil AX Axis center M Motor electromagnetic part Ra-Rd Rotation locus circle SH1 Motor shaft SH2 Encoder shaft SM Servo motor (an example of a motor)

Claims (14)

A motor with an encoder,
A motor electromagnetic section configured to rotate the motor shaft;
An electromagnetic brake configured to brake the motor shaft,
The encoder is
A magnet supported to rotate with the motor shaft;
A magnetic field sensor comprising a magnetic body having a large Barkhausen effect and configured to detect a magnetic field of the magnet;
A magnetic flux guiding member that induces the leakage flux so that the leakage flux from at least one of the motor electromagnetic part and the electromagnetic brake to the magnetic field sensor is in a direction orthogonal to the length direction of the magnetic field sensor,
motor. The magnetic field sensor is
The length direction is arranged so as to be parallel to the tangential direction of the rotation locus circle of the magnet,
The magnetic flux induction member is
The motor according to claim 1, wherein the motor is a magnetic member disposed on an outer peripheral side of the central portion in the length direction of the magnetic field sensor in a radial direction of the rotation locus circle. The encoder is
3. The motor according to claim 2, further comprising an encoder shaft made of a magnetic material that rotates with the motor shaft and is arranged to face the magnetic field sensor in the radial direction. The encoder shaft is
The motor according to claim 3, wherein the motor is separate from the motor shaft and is connected to the end of the motor shaft so as to have the same axis. The encoder is
5. The motor according to claim 4, further comprising a magnetic plate member disposed on a side opposite to the motor shaft of the encoder shaft in the axial direction and having a direction perpendicular to the axial direction as a plate surface direction. The encoder is
Having a substrate with electronic components,
The magnetic plate member is
The motor according to claim 5, wherein the motor is a board fixing member that is arranged on the encoder shaft side of the board in the axial direction and fixes the board. The magnetic flux induction member is
A strut member made of a magnetic material and supporting the substrate fixing member,
The motor according to claim 6. The encoder is
A disk coupled to the encoder shaft;
A light source configured to emit light to the disk;
A light receiving element installed on the substrate and configured to receive light from the disk;
The substrate fixing member is
The motor according to claim 6, further comprising an opening that exposes at least the light receiving element to the disk side. The encoder is
The motor according to any one of claims 1 to 8, comprising an encoder cover made of a magnetic material and accommodating the magnet, the magnetic field sensor, and the magnetic flux guiding member. The motor electromagnetic part or the electromagnetic brake and the encoder, and further includes a shield member made of a magnetic material and formed with an insertion hole for the encoder shaft of the motor shaft or the encoder. The motor according to any one of 1 to 9.   It is arranged between the motor electromagnetic part or the electromagnetic brake and the encoder, and is configured to generate a magnetic flux from the encoder side toward the motor electromagnetic part or the electromagnetic brake side on the axis of the motor shaft. The motor according to claim 1, further comprising a coil. A motor with an encoder,
A motor electromagnetic section configured to rotate the motor shaft;
An electromagnetic brake configured to brake the motor shaft,
The encoder is
A magnet supported to rotate with the motor shaft;
A magnetic field sensor comprising a magnetic body having a large Barkhausen effect and configured to detect a magnetic field of the magnet;
A motor that rotates together with the motor shaft and that is arranged to face the magnetic field sensor in a radial direction of a rotation locus circle of the magnet, and is made of a magnetic material. A motor encoder used in a motor having a motor electromagnetic unit configured to rotate a motor shaft,
A magnet supported to rotate with the motor shaft;
A magnetic field sensor comprising a magnetic body having a large Barkhausen effect and configured to detect a magnetic field of the magnet;
The leakage flux is set so that the leakage flux from at least one of the electromagnetic brake configured to brake the motor shaft and the motor electromagnetic unit to the magnetic field sensor is in a direction perpendicular to the length direction of the magnetic field sensor. A magnetic flux guiding member for guiding,
Encoder for motor. The motor encoder according to claim 13 , wherein the electromagnetic brake is integrally provided.

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