JP2020118593A - Manufacturing method of magnet assembly, magnet assembly and encoder - Google Patents

Abstract

To appropriately correct output of a magnetic sensitive element according to the deviation of polarization positions of a first magnet and a second magnet in an encoder.SOLUTION: An encoder 10 includes: a magnet holder 19 which integrally rotates with a rotation axis 2; and a magnet assembly 15 having a first magnet 161 and a second magnet 162 which are fixed to the magnet holder 19. The first magnet 161 has an N pole and an S pole magnetized for each pole in a circumferential direction and faces a first magnetic sensitive element 171, the second magnet 162 has a plurality of N poles and S poles alternately magnetized in the circumferential direction and faces a second magnetic sensitive element 172. The magnet assembly 15 manufactures by setting target positions of a magnetic pole of the first magnet 161 and a magnetic pole of the second magnet 162 so that angular positions of a magnetization polarization line M1 of the first magnet 161 and a magnetization polarization line M2 of the second magnet 162 does not match.SELECTED DRAWING: Figure 11

Description

The present invention relates to an encoder for detecting rotation of a rotor by a magnetic sensing element, a magnet assembly used in the encoder, and a method for manufacturing the magnet assembly.

Patent Document 1 discloses an encoder. The encoder of Patent Document 1 includes a magnetic sensing element mounted on a substrate and a magnet that rotates integrally with a rotating body (for example, a rotating shaft of a motor). The magnet is fixed to the magnet holder by adhesion or the like, and is fixed to the rotating shaft via the magnet holder. The substrate on which the magnetic sensing element is mounted is fixed to the frame of the motor via the support member. The magnet includes a first magnet in which one N pole and one S pole are magnetized in the circumferential direction, and a second magnet in which a plurality of N and S poles are alternately magnetized in the circumferential direction.

Japanese Patent No. 5666886

The encoder of Patent Document 1 detects the absolute angular position of the rotating body based on the output of the first magnetic sensing element. Further, the absolute angular position of the rotating body is detected with higher resolution based on the outputs of the first magnetic sensing element and the second magnetic sensing element. Here, when the polarization position of the first magnet facing the first magnetic sensing element and the polarization position of the second magnet facing the second magnetic sensing element are deviated, both senses are calculated when the absolute angular position is calculated. A correction process is performed to correct the output of the magnetic element according to the amount of deviation of the polarization position.

However, when the deviation amount of the polarization position is 0, the correction amount is either 0 or the maximum value. However, when the correction amount is 0 and the maximum value, the absolute angular position is the second magnet. There is a deviation by the polarization angle of the magnet at 360° (that is, 360°÷(2×polarization number)). Therefore, there is a problem that the absolute angular position greatly varies depending on whether the correction amount is 0 or the maximum value. That is, if the arrangement of the first magnet and the second magnet is set so that the deviation amount of the polarization position becomes 0, the detection result of the absolute angular position becomes unstable.

On the other hand, the absolute angular position can be obtained on the assumption that the amount of deviation of the polarization position is 0. However, this makes it possible to perform an appropriate correction process when the polarization position is displaced due to thermal deformation after the magnet is assembled. Can't do. Therefore, the absolute angular position cannot be detected accurately.

In view of the above problems, an object of the present invention is to provide a first magnet in which N poles and S poles are magnetized one by one, and a plurality of N poles and S poles are alternately magnetized in the circumferential direction. In a magnet assembly including two magnets, the output of the magnetic sensing element is appropriately corrected according to the deviation of the polarization positions of the first magnet and the second magnet.

In order to solve the above problems, the present invention has a magnet holder that rotates integrally with a rotation shaft, and a first magnet and a second magnet that are fixed to the magnet holder. N poles and S poles are magnetized one by one in the circumferential direction, and face the first magnetic sensitive element, and the second magnet is magnetized in a plurality of N poles and S poles alternately in the circumferential direction, and A method of manufacturing a magnet assembly facing the second magnetic sensing element, wherein a positional relationship in which the angular positions of the magnetic polarization line of the first magnet and the magnetic polarization line of the second magnet do not match. Thus, the magnet assembly is manufactured by setting target positions of the magnetic poles of the first magnet and the magnetic poles of the second magnet.

Further, the magnet assembly of the present invention includes a magnet holder that rotates integrally with a rotation shaft, and a first magnet and a second magnet that are fixed to the magnet holder. Each of the N pole and the S pole is magnetized one by one, and faces the first magnetic sensitive element, and the second magnet is magnetized in a plurality of N poles and S poles alternately in the circumferential direction, and The magnetized polarization line of the first magnet and the magnetized polarization line of the second magnet do not coincide with each other in angular position facing the magnetic sensing element.

In the present invention, as described above, the first magnet and the second magnet are assembled so that the angular positions of the respective magnetic polarization lines do not match. Therefore, since the state in which the polarization position shift amount is 0 is unlikely to occur, it is unlikely that a state in which either 0 or the maximum value can be adopted as the correction amount is generated. Therefore, it is possible to avoid a large variation in the correction amount according to the deviation of the position of the magnetic polarization line, resulting in a large variation in the absolute angular position.

In the method of manufacturing a magnet assembly according to the present invention, the first magnet and the second magnet are separated from each other in a radial direction, and the magnet holder has a shield portion arranged between the first magnet and the second magnet. It is preferable that the magnetized polarization line of the first magnet and the magnetized polarization line of the second magnet are aligned on the basis of a position reference provided on the shield part. For example, in the magnet assembly of the present invention, the first magnet and the second magnet are separated from each other in the radial direction, and the magnet holder includes a shield portion arranged between the first magnet and the second magnet. It is preferable that the shield part is provided with a position reference located at the same angular position as either the magnetized polarization line of the first magnet or the magnetized polarization line of the second magnet. With this configuration, the angular position of the magnetized polarization line can be accurately aligned with the position reference.

In the present invention, with respect to the position reference, the first magnet magnetized with one N pole and one S pole is positioned and fixed to the magnet holder, and the second magnet before magnetization is replaced with the magnet. After fixing to the holder, it is preferable to magnetize the second magnet with the position reference as a reference. With this configuration, it is possible to prevent the magnetized polarization line from deviating from the target position when being fixed to the magnet holder. Therefore, the angular position of the magnetized polarization line can be accurately aligned.

In the present invention, the first magnet and the second magnet are positioned at a position where the magnetized surface of the second magnet is projected beyond the magnetized surface of the first magnet and the tip end surface of the shield portion, It is preferably fixed to the magnet holder. Thus, by projecting the second magnet from the shield part, the second magnet can be magnetized after being fixed to the magnet holder. Therefore, it is possible to prevent the magnetized polarization line from deviating from the target position when it is fixed to the magnet holder. Therefore, the angular position of the magnetized polarization line can be accurately aligned.

In the present invention, the magnetized polarization line of the first magnet is preferably located at an angular position that coincides with the center of the N pole region or the S pole region of the second magnet in the circumferential direction. With this configuration, even if the position of the magnetized polarization line is displaced after assembly due to thermal deformation or the like, the angular position of the magnetized polarization line of the first magnet matches the angular position of the magnetized polarization line of the second magnet. Unlikely to happen. Therefore, it is possible to avoid a large variation in the correction amount according to the deviation of the position of the magnetic polarization line, resulting in a large variation in the absolute angular position.

Next, the encoder of the present invention receives the signals of the magnet assembly, the first magnetic sensing element and the second magnetic sensing element, and the signals of the first magnetic sensing element and the second magnetic sensing element. A circuit board set including a board on which an encoder circuit is provided, a reference surface on which the circuit board set is mounted, and an encoder holder including a magnet placement hole in which the magnet assembly is placed. To do.

According to the present invention, the first magnet and the second magnet are assembled so that the respective angular positions of the magnetic polarization lines do not match. Therefore, since the state where the polarization position shift amount is 0 is not generated, a state in which either 0 or the maximum value can be adopted as the correction amount does not occur. Therefore, it is possible to avoid a large variation in the correction amount according to the deviation of the position of the magnetic polarization line, resulting in a large variation in the absolute angular position.

It is an appearance perspective view of a motor with an encoder provided with an encoder to which the present invention is applied. It is sectional drawing (AA sectional drawing of FIG. 1) of an encoder, a 1st bearing holder, and a rotating shaft, and its partial enlarged view. It is sectional drawing (BB sectional drawing of FIG. 1) of an encoder, a 1st bearing holder, and a rotating shaft. It is an exploded perspective view which looked at an encoder, the 1st bearing holder, and a rotating shaft from the counter output side. It is an exploded perspective view which looked at an encoder, the 1st bearing holder, and a rotating shaft from the output side. It is a perspective view of the encoder and the 1st bearing holder which removed the encoder case. It is an exploded perspective view of an encoder and a first bearing holder from which an encoder case has been removed. It is an exploded perspective view which looked at a circuit board group from the counter output side. It is an exploded perspective view which looked at a circuit board set from the output side. It is an exploded perspective view of a magnet assembly. It is explanatory drawing which shows the position of the magnetic polarization line of a 1st magnet and a 2nd magnet. It is a flowchart of the manufacturing method of a magnet assembly. It is a partial exploded sectional view showing a positioning structure of a magnet assembly and a circuit board set. 7 is a flowchart of a method of assembling a magnet assembly and a circuit board set.

Embodiments of an encoder and a motor with an encoder to which the present invention is applied will be described below with reference to the drawings. FIG. 1 is an external perspective view of a motor 1 with an encoder including an encoder 10 to which the present invention is applied. 2 is a cross-sectional view (A-A cross-sectional view of FIG. 1) of the encoder 10, the first bearing holder 42A, and the rotary shaft 2 and a partially enlarged view thereof, and FIG. 3 is an encoder 10, the first bearing holder 42A, and It is sectional drawing (BB sectional drawing of FIG. 1) of the rotating shaft 2. 4 and 5 are exploded perspective views of the encoder 10, the first bearing holder 42A, and the rotary shaft 2, FIG. 2 is an exploded perspective view seen from the opposite output side L2, and FIG. 3 is seen from the output side L1. FIG.

The encoder-equipped motor 1 includes a motor 3 having a rotating shaft 2 and an encoder 10 for detecting rotation of the rotating shaft 2. In this specification, the three directions of XYZ are directions orthogonal to each other, and one side of these three directions is X1, Y1, Z1 and the other side is X2, Y2, Z2, respectively. The Z direction is parallel to the central axis L of the rotating shaft 2, and the X and Y directions are orthogonal to the central axis L.

(motor)
The motor 3 includes a motor case 4 that houses a rotor and a stator (not shown). The rotor rotates integrally with the rotating shaft 2, and the stator is fixed to the motor case 4. A driven member is connected to an end of the rotary shaft 2 that projects from the motor case 4 to the outside. In this specification, the direction in which the rotary shaft 2 projects from the motor case 4 is referred to as the output side L1, and the side opposite to the output side L1 is referred to as the counter output side L2. The encoder 10 is fixed to the end of the motor 3 on the opposite output side L2.

As shown in FIG. 1, the motor case 4 includes a tubular case 41 extending in the direction of the central axis L, a first bearing holder 42A fixed to an end of the tubular case 41 on the opposite output side L2, and a tubular case. A second bearing holder (not shown) fixed to the end of the output side L1 of 41 is provided. The encoder 10 is fixed to the first bearing holder 42A from the counter output side L2. As shown in FIG. 4, the first bearing holder 42</b>A has a circular recess 44 that is recessed toward the output side L<b>1, a flange 45 that expands to the outer peripheral side of the circular recess 44, and projects toward the opposite output side L<b>2 along the edge of the circular recess 44. And an annular wall 46.

As shown in FIGS. 2 to 4, the bearing 43 is held at the center of the bottom of the circular recess 44. The bearing 43 rotatably supports the end of the rotary shaft 2 on the opposite output side L2. An annular plate 47 is attached to the bottom of the circular recess 44 so as to press the outer peripheral portion of the bearing 43 from the opposite output side L2. The rotary shaft 2 is passed through a through hole 48 provided at the center of the plate 47 and supported by the bearing 43. The plate 47 is fixed to the bottom of the circular recess 44 with three screws.

In this embodiment, the plate 47 is made of a magnetic material and shields magnetic noise from the motor 3 side to the encoder 10 side. Notches 471 are formed on the outer peripheral edge of the plate 47 at three locations at equal angular intervals. The leg portion 150 of the encoder holder 14, which will be described later, is disposed in the notch 471.

(Encoder)
As shown in FIGS. 2 to 5, the encoder 10 includes an encoder case 11 fixed to the first bearing holder 42</b>A, an encoder cover 12 arranged inside the encoder case 11, and an encoder cover 12 arranged inside the encoder cover 12. The circuit board set 13, the encoder holder 14 to which the circuit board set 13 is fixed, the magnet assembly 15 arranged on the inner peripheral side of the encoder holder 14, and the encoder case 11 and the encoder cover 12. A cable guide member 20 is provided.

The magnet assembly 15 includes a magnet 16 arranged on the surface on the opposite output side L2 and is fixed to the tip of the opposite output side L2 of the rotating shaft 2. Therefore, the magnet 16 rotates integrally with the rotating shaft 2. The circuit board set 13 includes a board holder 50 and a board 60 fixed to the board holder 50. The circuit board set 13 includes a magnetic sensitive element 17 facing the magnet 16 fixed to the rotary shaft 2, and the signal of the magnetic sensitive element 17 is input to the encoder circuit on the substrate 60. In this embodiment, an MR element is used as the magnetic sensing element 17.

(Encoder case)
The encoder case 11 includes a substantially rectangular end plate portion 111 when viewed in the direction of the central axis L, and a tubular side plate portion 112 that extends from the outer peripheral edge of the end plate portion 111 to the output side L1. As shown in FIG. 1, a wiring lead-out portion 113 for passing the encoder cable 5 is provided on the side surface of the side plate portion 112 facing the X1 side. As shown in FIGS. 4 and 5, the wiring lead-out portion 113 includes a cutout portion 117 formed in the side plate portion 112, a holding member 118 attached to the cutout portion 117, a holding member 118 and the cutout portion 117. A covering encoder cable holder 119 is provided.

The encoder case 11 and the first bearing holder 42A are fixed by interposing the seal member 114 between the end surface of the output side L1 of the side plate portion 112 and the flange 45 and tightening the fixing screws at the four corners. It In this embodiment, the encoder case 11 and the motor case 4 are made of a non-magnetic material such as aluminum.

(Encoder holder)
As shown in FIGS. 4 and 5, the encoder holder 14 includes a body portion 140 in which a circular magnet arrangement hole 141 is formed, and three leg portions 150 protruding from the body portion 140 to the outer peripheral side. As shown in FIG. 5, the end surface on the output side L1 of the leg portion 150 projects to the output side L1 more than the end surface on the output side L1 of the body portion 140. The leg 150 is arranged inside the circular recess 44 of the first bearing holder 42A, is arranged in a notch 471 formed in the outer peripheral edge of the plate 47, and abuts on the bottom surface of the circular recess 44. The leg portion 150 is provided with a fixing hole 147 through which the holder fixing screw 145 is inserted. The encoder holder 14 is fixed to the first bearing holder 42A by screwing the leg portion 150 to the bottom surface of the circular recess 44 with the three holder fixing screws 145. When the encoder holder 14 is fixed to the first bearing holder 42A, the rotary shaft 2 and the magnet assembly 15 are arranged in the center of the magnet arrangement hole 141.

The circuit board set 13 is fixed to the encoder holder 14. As shown in FIG. 4, the encoder holder 14 includes an annular surface 143 that is an end surface of the body portion 140 on the opposite output side L2, and includes boss portions 144 protruding from the annular surface 143 at three locations. The circuit board set 13 is screwed to the boss 144 by three board fixing screws 65. The circuit board set 13 is positioned in the central axis L direction by hitting the reference surface P, which is the tip surface of the boss portion 144, from the opposite output side L2. By fixing the circuit board set 13 to the encoder holder 14, the magnetic sensitive element 17 mounted on the circuit board set 13 and the magnet 16 of the magnet assembly 15 face each other with a predetermined gap.

The encoder holder 14 includes a penetrating portion 148 that radially penetrates the body portion 140 that surrounds the magnet arrangement hole 141. The penetrating portion 148 is provided at two locations that are separated from each other in the circumferential direction. In the present embodiment, the penetrating portion 148 is a cutout portion that is formed by cutting the body portion 140 from the end portion of the output side L1 to the opposite output side L2. If the penetrating portion 148 is provided, when the magnet assembly 15 is fixed to the end portion of the rotary shaft 2 on the opposite output side L2, from the outer peripheral side of the encoder holder 14 fixed to the first bearing holder 42A, the magnet arrangement hole is formed. 141 can be accessed using a fixing tool such as a screwdriver.

When fixing the circuit board set 13 to the encoder holder 14, the positioning of the circuit board set 13 in the circumferential direction is performed using the positioning pins 66. As shown in FIG. 5, the circuit board set 13 includes two positioning holes 131 into which the ends of the positioning pins 66 fit. The positioning hole 131 is provided in the substrate holder 50. On the other hand, as shown in FIG. 4, the encoder holder 14 is provided with two convex portions projecting to the opposite output side L2 from the annular surface 143, and the end portion of the positioning pin 66 is fitted into each convex portion. A positioning hole 146 is provided. The encoder holder 14 and the circuit board set 13 are fitted in the positioning hole 146 of the encoder holder 14 and the positioning hole 131 of the circuit board set 13 at one end and the other end of the two positioning pins 66, respectively, at two locations separated in the circumferential direction. Positioning in the circumferential direction by inserting. Since the positioning pin 66 is a spring pin, it is possible to prevent the rattling of the circuit board set 13 in the circumferential direction and perform positioning.

(Encoder cover)
FIG. 6 is a perspective view of the encoder 10 with the encoder case 11 removed and the first bearing holder 42A. FIG. 7 is an exploded perspective view of the encoder 10 with the encoder case 11 removed and the first bearing holder 42A. As shown in FIGS. 2 to 7, the encoder cover 12 includes an end plate portion 121 facing the circuit board set 13 from a side opposite to the magnet 16 (counter output side L2) and an outer peripheral edge of the end plate portion 121. From the output side L1. 2,
As shown in FIG. 3, the encoder cover 12 covers the circuit board set 13 from the side opposite to the magnet 16 (opposite output side L2). The side plate portion 122 surrounds the outer peripheral side of the circuit board set 13, and surrounds the outer peripheral side of the magnetic sensing element 17 mounted on the circuit board set 13. The tip of the side plate portion 122 extends to the output side L1 with respect to the circuit board set 13. As shown in FIGS. 3 and 6, the encoder cover 12 is positioned in the central axis L direction by the tip of the side plate 122 contacting the annular surface 143 of the encoder holder 14.

The encoder cover 12 includes an opening 123 facing the side opposite to the wiring take-out portion 113 (X2 side). The opening 123 is a notch formed by linearly cutting a part of the end plate 121 and the side plate 122 in the circumferential direction in a plane orthogonal to the radial direction. The end portion of the circuit board set 13 on the X2 side is arranged outside the encoder cover 12. Therefore, the substrate 60 includes an exposed portion 61A arranged outside the opening 123 and a housing portion 61B housed in the encoder cover 12. The circuit board set 13 includes the connector 18 arranged on the exposed portion 61</b>A of the board 60. By arranging the connector 18 outside the encoder cover 12, the height of the encoder cover 12 can be reduced, and the overall height of the encoder 10 can be reduced.

As shown in FIG. 6, the opening 123 of the encoder cover 12 includes a linear portion 127 that overlaps with the circuit board set 13 when viewed from the opposite output side L2. The straight line portion 127 is an end portion of the end plate portion 121 and extends in the Y direction. The connector 18 is arranged along the central portion of the linear portion 127 with the longitudinal direction facing the Y direction. At the center of the straight line portion 127, a bent portion 128 is provided by bending the edge of the end plate portion 121 toward the X1 side. As will be described later, a cable passage 23 through which the encoder cable 5 connected to the connector 18 passes is provided between the encoder cover 12 and the encoder case 11. The cable passage 23 extends in the X direction and overlaps with the central portion of the linear portion 127 when viewed from the opposite output side L2. The bent portion 128 is provided in a range facing the cable passage 23.

The encoder cover 12 is fixed to the circuit board set 13 by a conductive fixing member 125. As shown in FIG. 4, the encoder cover 12 is provided with two fixing holes 124 penetrating the end plate portion 121. Further, the circuit board set 13 is provided with fixing holes 132 at two positions facing the fixing holes 124 of the encoder cover 12. The encoder cover 12 is fixed to the circuit board assembly 13 by fitting one ends of the two fixing members 125 into the fixing holes 132 and fitting the other ends into the fixing holes 124 of the encoder cover 12. The fixing holes 124 and 132 are provided at two locations that are separated from each other in the circumferential direction. The fixing member 125 is a spring pin, and the ends of the fixing member 125 are press-fitted into the fixing holes 124 and 132. By using the spring pin as the fixing member 125, the rattling of the encoder cover 12 in the circumferential direction is prevented. Therefore, the fixing member 125 can position the encoder cover 12 in the circumferential direction.

The fixing member 125 is a conductive member made of a conductive metal (for example, SUS). The fixing hole 132 is provided in the substrate 60, and one of the two places is a ground through hole 133 provided with a land electrically connected to the signal ground of the encoder circuit on the substrate 60. Therefore, by fitting the fixing members 125 into the two fixing holes 132, one of the two fixing members 125 is electrically connected to the signal ground of the encoder circuit on the substrate 60.

The encoder cover 12 is made of a conductive magnetic material and functions as a shield member (first shield member). For example, the encoder cover 12 is made of iron, permalloy or the like. In this embodiment, the encoder cover 12 is formed by pressing a magnetic metal plate such as SPCC or SPCE. In this way, the encoder cover 1 made of a magnetic material
By covering the circuit board set 13 provided with the magnetic sensitive element 17 with the magnetic material 2, the magnetic material absorbs magnetic noise such as a disturbance magnetic field and electromagnetic wave noise, and shields the magnetic sensitive element 17 and the encoder circuit from magnetic noise and electromagnetic wave noise. be able to. Further, the encoder cover 12 is electrically connected to the signal ground of the encoder circuit via one of the two fixing members 125. In this way, by covering the circuit board set 13 with the member having the signal ground potential, the magnetic sensing element 17 and the encoder circuit can be shielded from electrical noise such as frame ground noise from the motor case 4.

As will be described later, the circuit board set 13 includes a board holder 50 that covers the board 60 from the output side L1, and the board holder 50 includes a shield member 80 (second shield) so as to cover the magnetic sensing element 17. Member) is attached. The substrate holder 50 and the shield member 80 are made of a conductive metal such as aluminum and are connected to the signal ground of the encoder circuit. Therefore, the magnetic sensing element 17 and the encoder circuit are shielded from electrical noise from the side of the magnet 16 as well, and thus shielded from electrical noise in all directions except the opening 123.

(Dustproof member)
As shown in FIG. 2, a dustproof member 126 that closes the opening 123 is arranged between the encoder cover 12 and the substrate 60. The dustproof member 126 is made of an elastic member, and is compressed between the end plate portion 121 of the encoder cover 12 and the substrate 60 when the encoder cover 12 is fixed to the circuit board set 13. As shown in FIGS. 5 to 7, the dustproof member 126 is a linear member, and extends linearly along the edge of the opening 123. By disposing the dustproof member 126 in the opening 123, it is possible to prevent conductive foreign matter from entering the substrate 60.

As shown in FIG. 6, the dustproof member 126 extends in the Y direction along the linear portion 127 of the opening 123. As shown in FIG. 5, the dustproof member 126 is a rectangular parallelepiped member having a constant width in the X direction and a constant height in the Z direction. The arrangement area C (see FIG. 2) of the dustproof member 126 is closer to the opening 123 side (X2 side) than the center of the substrate 60. As will be described later, the magnetic sensitive element 17 includes a first magnetic sensitive element 171 mounted at the center of the substrate 60 and a second magnetic sensitive element 172 arranged at the edge of the substrate holder 50 on the X1 side. Of the two magnetic sensitive elements, the magnetic sensitive element arranged closest to the connector 18 side is the first magnetic sensitive element 171, and the dustproof member 126 has the opening 123 side with respect to the center of the first magnetic sensitive element 171 ( Located on the X2 side). The second magnetic sensing element 172 is arranged at the end portion on the side opposite to the side where the dustproof member 126 is arranged with respect to the center of the substrate 60, and at a position where it does not overlap the dustproof member 126 when viewed from the opposite output side L2. It is arranged.

The dustproof member 126 is an insulating porous body. For example, the dustproof member 126 is a foam made of an insulating material such as rubber or urethane. In the present embodiment, the dustproof member 126 is a semi-independent semi-open cell and is made of EPDM (ethylene/propylene/diene rubber). As described above, since the dustproof member 126 is a sponge-like soft elastic member, the dustproof member 126 is deformed into a shape in which it is in close contact with both members between the substrate 60 and the encoder cover 12, and closes the opening 123. The shape of the dustproof member 126 before assembly is larger than the gap between the encoder cover 12 and the substrate 60, and is compressed by assembling.

Instead of using a porous body as the dustproof member 126, an insulating filler may be injected into the gap between the encoder cover 12 and the substrate 60 to close the gap. For example, a silicone rubber-based elastic adhesive that cures at room temperature can be used as the filler.

(Cable guide member)
As shown in FIGS. 2 to 5, two cable guide members 20 having the same shape are arranged between the encoder case 11 and the encoder cover 12. The cable guide member 20 includes a guide surface 21 that is parallel to the XZ plane, and an arc surface 22 that faces the side opposite to the guide surface 21. The two cable guide members 20 are fixed to the encoder case 11 such that the arcuate surfaces 22 are located on the same circle and the guide surfaces 21 face each other in the Y direction. The end plate portion 111 of the encoder case 11 is provided with a positioning portion for positioning the two cable guide members 20 in the arrangement shown in FIGS. 2 and 3.

As shown in FIG. 3, the encoder case 11 includes an arc-shaped rib 115 that projects from the end plate portion 111 to the output side L1, and a convex portion 116 that is provided on the inner peripheral side of the rib 115. The rib 115 and the convex portion 116 are positioning portions for positioning the cable guide member 20. The rib 115 contacts the circular arc surface 22 of the cable guide member 20, and the convex portion 116 is arranged in the positioning hole 24 penetrating the cable guide member 20. The cable guide member 20 is fixed to the end plate portion 111 with an adhesive, for example.

The cable guide member 20 is made of an elastic member and is compressed between the end plate portion 121 of the encoder cover 12 and the end plate portion 111 of the encoder case 11. The cable guide member 20 is an insulating porous body like the dustproof member 126. In the present embodiment, the dustproof member 126 is a closed cell body and is made of a microcell polymer sheet. The encoder cover 12 is pressed against the encoder holder 14 by the elastic return force of the cable guide member 20. Therefore, it is possible to reduce the risk of the encoder cover 12 coming off the circuit board assembly 13 due to vibration or the like.

The space between the two cable guide members 20 serves as a cable passage 23 extending in the X direction. As shown in FIG. 2, in the circuit board set 13, the connector 18 is arranged at an end (X2 side end) opposite to the wiring take-out portion 113 with the center of the board 60 interposed therebetween. 181 faces the side opposite to the wiring take-out portion 113 (X2 side). As shown in FIGS. 2 and 6, the cable-side connector 6 provided at the tip of the encoder cable 5 is connected to the insertion port 181 of the connector 18 from the side opposite to the wiring take-out portion 113. The encoder cable 5 is pulled out from the connector 18 to the X2 side, bent at the X2 side of the connector 18 so as to be folded back to the X1 side, and is routed to the wiring takeout portion 113 through the cable passage 23. Therefore, the encoder cable 5 is pulled out from the connector 18 to the side opposite to the wiring take-out portion 113 and folded back to the wiring take-out portion 113 side, and the cable take-out portion 113 side is provided along the cable guide member 20. A second portion 5B that linearly extends to is provided.

As described above, the opening portion 123 of the encoder cover 12 is provided with the bent portion 128 in the range facing the cable passage 23. Therefore, the encoder cable 5 does not come into contact with the edge of the end plate portion 121 but comes into contact with the bent portion 128, so that the encoder cable 5 is less likely to be damaged.

(Circuit board assembly)
8 is an exploded perspective view of the circuit board set 13 as viewed from the opposite output side L2, and FIG. 9 is an exploded perspective view of the circuit board set 13 as viewed from the output side L1. As shown in FIGS. 8 and 9, the circuit board set 13 includes a board holder 50, a board 60 that contacts the board holder 50 from the opposite output side L2, and a conductive material that fixes the board 60 to the board holder 50. And a shield member 80 fixed to the substrate holder 50 from the output side L1. The board 60 is substantially circular when viewed in the direction of the central axis L, and the connector 18 is mounted on the edge on the X2 side. The connector 18 is arranged along a straight line portion 61 in which the edge of the substrate 60 is linearly cut out. The substrate holder 50 has substantially the same shape as the substrate 60 when viewed in the central axis L direction, and the substrate 60 and the substrate holder 50 are in contact with each other in the central axis L direction.

Fixing holes 62 for fixing to the substrate holder 50 are formed in the substrate 60 at two locations. The two fixing holes 62 are arranged on opposite sides of the center of the substrate holder 50. Further, one of the two fixing holes 62 is a ground through hole 621 that is electrically connected to the signal ground of the encoder circuit mounted on the substrate 60. Either of the two fixing holes 62 may be the ground through hole 621. Further, the fixing holes 62 may be provided at three or more places, and the substrate 60 and the substrate holder 50 may be fixed at the three places.

The substrate holder 50 includes a flat portion 53 that faces the substrate 60, and an edge portion 54 that rises from the outer peripheral edge of the flat portion 53 to the opposite output side L2. Fixed holes 51 are formed in the flat portion 53 at two locations facing the fixed holes 62 of the substrate 60. The substrate 60 is fixed to the substrate holder 50 by fitting one end and the other end of the fixing member 70 into the fixing hole 62 of the substrate 60 and the fixing hole 51 of the substrate holder 50, respectively. The fixing member 70 is a spring pin. By using the spring pin as the fixing member 70, rattling of the substrate 60 with respect to the substrate holder 50 is prevented. Further, as described above, the fixing member 70 is a conductive member formed of a conductive metal, for example, SUS, and one of the fixing holes 62 is the ground through hole 621. When the substrate 60 is attached to the substrate holder 50, the substrate holder 50 is electrically connected to the signal ground of the encoder circuit mounted on the substrate 60 via the fixing member 70 and the ground through hole 621. The fixing member 70 may be fixed to the fixing hole 62 by soldering.

The board holder 50 is formed with boss portions 52 for passing the board fixing screws 65 at three locations corresponding to the boss portions 144 of the encoder holder 14. In the present embodiment, the tip end surface of the boss portion 52 on the opposite output side L2 is the contact surface that contacts the substrate 60. Further, the end surface on the output side L1 of the boss portion 52 is a contact surface that contacts the encoder holder 14.

Fixing holes 63 are formed in the substrate 60 at three locations facing the boss portion 52. In the circuit board set 13, the three board fixing screws 65 are respectively passed through the fixing holes 63 of the board 60 and the boss portion 52 of the board holder 50, and the tips thereof are screwed to the boss portion 144 of the encoder holder 14, It is fixed to the encoder holder 14. The encoder holder 14 is made of an insulating material such as resin. Therefore, when the circuit board set 13 is fixed to the first bearing holder 42A via the encoder holder 14, the board holder 50 is insulated from the first bearing holder 42A.

The substrate 60 includes a non-output side substrate surface 60a facing the non-output side L2 and an output side substrate surface 60b facing the output side L1. On the non-output side substrate surface 60a, circuit elements forming an encoder circuit, a connector 18 for connecting the encoder cable 5, a connection terminal 173, and the like are mounted. The connection terminals 173 are arranged on the outer peripheral edge of the substrate 60, and are arranged on the opposite side of the connector 18 with the center of the substrate 60 interposed therebetween. A notch 64 is formed on the outer peripheral edge of the substrate 60 on the radially outer side of the connection terminal 173. As shown in FIG. 9, the magnetic sensing element 17 includes a first magnetic sensing element 171 arranged at the center of the output side substrate surface 60b and a second magnetic sensing element 17 connected to the connection terminal 173 via the flexible wiring board 174. A magnetic element 172 is provided. The flexible wiring board 174 passes through the cutout portion 64 of the board 60 and is routed to the output side L1 of the board 60. Each of the first magnetic sensing element 171 and the second magnetic sensing element 172 includes a ground terminal (not shown) connected to the signal ground of the encoder circuit formed on the substrate 60. Further, two Hall elements 175 are mounted on the output side substrate surface 60b in the vicinity of the first magnetic sensing element 171. The two Hall elements 175 are arranged at angular positions separated by 90 degrees with respect to the position of the magnetic sensing element 17.

A circular through hole 56 is formed in the center of the flat surface portion 53 of the substrate holder 50. In addition, a step portion 57 that projects toward the output side L1 is formed on the output side L1 surface of the flat surface portion 53. The step portion 57 extends in a band shape from the region surrounding the through hole 56 toward the outer peripheral edge of the flat surface portion 53. A substantially rectangular through hole 58 is formed in the step portion 57. When the substrate 60 is fixed to the substrate holder 50, the first magnetic sensing element 171 and the Hall element 175 are arranged in the through hole 56. Further, in the through hole 58, a second magnetic sensitive element 172 connected to the connection terminal 173 on the substrate 60 via the flexible wiring substrate 174 is arranged. The second magnetic sensing element 172 is fixed to the edge of the through hole 58 and mounted on the substrate holder 50.

As will be described later, a circular first magnet 161 and an annular second magnet 162 coaxially arranged with the first magnet 161 are arranged at the tip of the magnet assembly 15 on the opposite output side L2. When the circuit board set 13 is fixed to the encoder holder 14, the first magnetic sensing element 171 and the first magnet 161 face each other, and the second magnetic sensing element 172 and the second magnet 162, as shown in FIGS. Face each other. The encoder 10 includes a predetermined gap between the surface of the output side L1 of the first magnetic sensing element 171 and the first magnet 161, and between the surface of the output side L1 of the second magnetic sensing element 172 and the second magnet 162. Are assembled to form. As will be described later, in the present embodiment, the gap between the magnetic sensitive element 17 and the magnet 16 is accurately managed by positioning the magnet assembly 15 and the circuit board set 13 with the reference plane P of the encoder holder 14 as a reference.

The first magnetic sensitive element 171 and the two Hall elements 175 arranged in the vicinity thereof and the first magnet 161 determine the output cycle of the first magnetic sensitive element 171 obtained by one rotation by the two Hall elements 175. By doing so, it functions as an absolute encoder. On the other hand, the second magnetic sensing element 172 and the second magnet 162 function as an incremental encoder because an output of a plurality of cycles can be obtained by one rotation. The encoder 10 can perform high-resolution and high-accuracy position detection by processing the outputs of these two sets of encoders.

(Shield member)
The shield member 80 is attached to the step portion 57 of the substrate holder 50 from the output side L1. The shield member 80 is a flexible sheet material, and has a size that completely closes the through holes 56 and the through holes 58 formed in the step portion 57. The step portion 57 has a shield mounting surface 59 facing the output side L1, and the shield member 80 is fixed to the shield mounting surface 59 via a conductive adhesive. As described above, the shield member 80 is formed of a conductive non-magnetic metal, such as aluminum, like the substrate holder 50. Therefore, the shield member 80 is electrically connected to the signal ground of the encoder circuit mounted on the substrate 60 via the substrate holder 50.

The shield member 80 covers the first magnetic sensing element 171 arranged in the through hole 56 and the second magnetic sensing element 172 arranged in the through hole 58. Therefore, the first magnetic sensitive element 171 and the second magnetic sensitive element 172 face the first magnet 161 and the second magnet 162 via the shield member 80. By attaching the shield member 80 to the substrate holder 50, the first magnetic sensitive element 171 and the second magnetic sensitive element 172 are shielded from the motor 3 by the members having the signal ground potential (the substrate holder 50 and the shield member 80). Therefore, it is possible to effectively shield frame ground noise, power source noise, and the like that come around from the gap between the first magnet 161 and the second magnet 162. The first magnetic sensing element 171 and the second magnetic sensing element 172 face the first magnet 161 and the second magnet 162 via the shield member 80, but since the shield member 80 is a nonmagnetic metal, electromagnetic noise With respect to the above, the function as the magnetic encoder is not impaired while the shielding is excellent.

(Magnet assembly)
FIG. 10 is an exploded perspective view of the magnet assembly. The magnet assembly 15 includes a magnet holder 19 and a magnet 16 held by the magnet holder 19. As shown in FIG. 10, the magnet holder 19 includes a substantially disc-shaped magnet holding portion 191 and a cylindrical shaft portion 192 that projects from the center of the magnet holding portion 191 to the output side L1. The tip of the rotary shaft 2 is fixed to the shaft portion 192 by any one of press fitting, an adhesive, and a set screw, or by using these together. As shown in FIGS. 2 and 3, in the present embodiment, a set screw 196 is tightened in a screw hole 195 that penetrates the shaft portion 192 in the radial direction, and the rotation is arranged in the shaft hole 197 that passes through the center of the shaft portion 192. The shaft 2 is fixed from the side. As shown in FIG. 10, the magnet 16 is fitted to the circular first magnet 161 that fits in the recess formed in the center of the magnet holding portion 191, and the stepped portion formed on the outer peripheral edge of the magnet holding portion 191. An annular second magnet 162 is provided to be fitted.

The magnet holder 19 is made of a magnetic material such as iron. The magnet holding portion 191 includes a shield portion 193 for suppressing magnetic interference between the first magnet 161 and the second magnet 162, and a yoke portion 194 located on the output side L1 of the second magnet 162. In the magnet assembly 15, the first magnet 161 and the second magnet 162 are radially separated from each other, and the shield part 193 is arranged between the first magnet 161 and the second magnet 162. The shield portion 193 is an annular convex portion that projects to the opposite output side L2, and the yoke portion 194 extends annularly outward in the radial direction on the output side L1 of the second magnet 162.

The first magnet 161 is provided with a magnetized surface 161a facing the opposite output side L2, and the magnetized surface 161a is located at a position recessed from the tip end surface 193a of the shield part 193 toward the output side L1 (see FIG. 13). .. The second magnet 162 is provided with a magnetized surface 162a facing the counter output side L2, and the magnetized surface 162a is counter output side L2 (the second magnetic sensitive element 172 side) from the tip end surface 193a of the shield part 193. It is located at a position projecting to (see FIG. 13). The first magnet 161 and the second magnet 162 are in radial contact with the shield portion 193. The shield portion 193 is a wide convex portion having a height in the central axis L direction (that is, the axial direction of the rotating shaft 2) smaller than the width in the radial direction.

FIG. 11 is an explanatory view showing the positions of the magnetization polarization lines of the first magnet 161 and the second magnet, and is a plan view of the magnet assembly 15 as seen from the opposite output side L2. The first magnet 161 is magnetized such that one north pole and one south pole are arranged in the circumferential direction. On the other hand, the second magnet 162 has a plurality of N poles and S poles alternately magnetized in the circumferential direction. In the example shown in FIG. 11, the second magnet 162 is provided with 64 magnetic pole pairs. The number of magnetic pole pairs is not limited to 64.

In the magnet assembly 15, the positions of the magnetization polarization lines of the first magnet 161 and the second magnet 162 do not match. As shown in FIG. 11, the magnetization polarization line M1 of the first magnet 161 is the center in the circumferential direction of the N pole region or the S pole region of the second magnet 162 (that is, the magnetization polarization lines M2 adjacent to each other in the circumferential direction). It is located at the same angular position as the intermediate point). The magnet holder 19 has a position reference for aligning the positions of the magnetic polarization lines M1 and M2 with the target position. In this embodiment, a mark serving as a position reference is provided, and the mark is the marking line 198 provided on the tip surface 193a of the shield portion 193. The marking line 198 extends in the radial direction and is provided at two locations on the opposite sides in the radial direction. The angular position of the marking line 198 coincides with the target position of the magnetized polarization line M1 of the first magnet 161.

The position reference provided on the magnet holder 19 for aligning the positions of the magnetic polarization lines M1 and M2 may be different from the marking line 198. For example, the position reference may be a concave portion, a convex portion, or a notch. Further, by providing a shape that fits with the position reference on the side of the first magnet 161, positioning can be performed by mechanical fitting.

(Method of manufacturing magnet assembly)
FIG. 12 is a flowchart of the method for manufacturing the magnet assembly 15. The magnet assembly 15 is manufactured by setting the target positions of the magnetic poles of the first magnet 161 and the second magnet 162 such that the angular positions of the magnetized polarization lines M1 and M2 do not match. As shown in FIG. 11, the target position of the first magnet 161 is a position where the angular position of the magnetized polarization line M1 and the marking line 198 (mark as a position reference) match. Further, the target position of the second magnet 162 is a position where the center in the circumferential direction of the N pole region or the S pole region (the midpoint between the magnetized polarization lines M2 adjacent in the circumferential direction) and the angular position of the marking line 198 coincide. Is.

As shown in FIG. 12, in step ST11, the magnetized first magnet 161 is positioned and fixed to the magnet holder 19. At this time, the magnetized polarization line M1 of the first magnet 161 and the angular position of the scribe line 198 are aligned with each other with respect to the scribe line 198, whereby the first magnet 161 is circumferentially positioned and the first magnet 161 is positioned. Positioning is performed in the direction of the central axis L so that the magnetized surface 161a of the shield part 193 is located at a position recessed closer to the output side L1 than the tip end surface 193a of the shield part 193. The first magnet 161 is fixed to the magnet holding portion 191 by a method such as press fitting or an adhesive.

Next, in the second step ST12, the second magnet 162 before being magnetized is fixed to the step portion of the outer peripheral edge of the magnet holding portion 191. At this time, since the second magnet 162 is not magnetized yet, positioning in the circumferential direction is not performed, but the surface of the non-output side L2 (the surface to be the magnetized surface 162a) is opposite to the end surface 193a of the shield part 193. The second magnet 162 is positioned and fixed in the direction of the central axis L so that the second magnet 162 is positioned so as to project toward the output side L2. The second magnet 162 is fixed to the magnet holding portion 191 by a method such as press fitting or an adhesive.

Subsequently, in a third step ST13, the second magnet 162 fixed to the magnet holding portion 191 is set on the magnetizer, and the position of the magnetized polarization line M2 is set to the position shown in FIG. 11 with reference to the marking line 198. The second magnet 162 is magnetized so that That is, the second magnet 162 is magnetized so that the midpoint of the adjacent magnetic polarization lines M2 in the circumferential direction coincides with the angular position of the magnetic polarization line M1. In this way, by providing the marking line 198 serving as the position reference, the positional accuracy of the magnetized polarization lines M1 and M2 can be improved.

(Management of gap between magnetic sensitive element and magnet)
FIG. 13 is a partially exploded cross-sectional view showing a positioning structure of the magnet assembly 15 and the circuit board set 13, and is a partially exploded cross-sectional view taken along the line DD of FIG. In the encoder 10, in order to accurately manage the gap between the magnetic sensing element 17 and the magnet 16, the magnet assembly 15 and the circuit board set 13 are assembled with the reference plane P provided in the encoder holder 14 as a reference. As described above, the reference surface P is the tip surface of the boss portion 144 with which the circuit board set 13 contacts. As shown in FIG. 7, the reference planes P are provided at three locations spaced in the circumferential direction.

As shown in FIG. 13, in the magnet assembly 15, the position H1 of the magnetized surface 161a of the first magnet 161, the position H2 of the tip end surface 193a of the shield part 193, and the position of the magnetized surface 162a of the second magnet 162. H3 differs from the central axis L direction. In the magnet assembly 15, the surface closest to the opposite output side L2 is the magnetized surface 162a of the second magnet 162. The magnet assembly 15 is positioned at a position where the reference plane P and the magnetized surface 162a of the second magnet 162 have a predetermined positional relationship in the central axis L direction, and is fixed to the rotary shaft 2. In this embodiment, the magnet assembly 15 is positioned and fixed to the rotary shaft 2 at a position where the reference plane P and the magnetized surface 162a are in the same plane.

In this way, when the reference surface P and the magnetized surface 162a are arranged on the same surface and then the boss portion 52 of the circuit board set 13 is abutted and fixed to the reference surface P, the second magnetic sensing element is used. The gap G between the sensor surface 172a of 172 and the magnetized surface 162a coincides with the height difference between the tip surface of the boss portion 52 and the sensor surface 172a in the circuit board set 13, as shown in FIG. The second magnetic sensing element 172 is mounted by positioning the shield mounting surface 59 of the substrate holder 50 and the sensor surface 172a on the same surface. That is, in the circuit board set 13, the shield mounting surface 59 is a sensor reference surface provided on the board holder 50. Therefore, since the gap G between the sensor surface 172a and the magnetized surface 162a is the height difference between the shield mounting surface 59 (sensor reference surface) of the substrate holder 50 and the tip end surface of the boss portion 52, the management of the gap G is This can be done by controlling the dimensional accuracy of the substrate holder 50. In this embodiment, since the substrate holder 50 is made of aluminum, the processing accuracy can be easily increased. Therefore, the gap G can be managed accurately.

FIG. 14 is a flowchart of a method of assembling the magnet assembly 15 and the circuit board set 13. As shown in FIG. 14, in step ST21, the encoder holder 14 is fixed to the motor case 4 (first bearing holder 42A). Next, in step ST22, the magnet assembly 15 is positioned at a position where the reference surface P provided on the encoder holder 14 and the magnetized surface 162a of the second magnet 162 have a predetermined positional relationship. In the present embodiment, this positioning is performed using a plate-shaped jig 100. For example, the positioning surface 101 provided on the jig 100 is brought into contact with the reference surface P, and the magnetized surface 162a of the second magnet 162 is brought into contact with the positioning surface 101.

Then, in step ST23, the magnet assembly 15 is fixed to the rotating shaft 2. In the present embodiment, the penetration hole 148 of the encoder holder 14 is used to access the screw hole 195 provided in the shaft portion 192 of the magnet holder 19 using a fixing tool such as a screwdriver, and the set screw 196 is tightened in the screw hole 195. To be crowded. As a result, the rotating shaft 2 is pressed against the inner peripheral surface of the shaft hole 197 of the magnet holder 19 by the tip of the set screw 196, and the magnet holder 19 is fixed to the rotating shaft 2. The screw holes 195 are provided at two places spaced apart in the circumferential direction, and a set screw 196 is screwed into each screw hole 195. Therefore, the encoder holder 14 is provided with penetrating portions 148 at two positions at the same angular intervals as the angular intervals of the two screw holes 195 provided on the magnet holder 19.

Next, in step ST24, the circuit board set 13 is fixed to the encoder holder 14. At this time, the boss portions 52 of the circuit board set 13 are brought into contact with the three reference surfaces P provided on the encoder holder 14 to perform positioning in the central axis L direction. The positioning in the circumferential direction is performed by the positioning pin 66 described above. After positioning, the circuit board set 13 is fixed to the encoder holder 14 by the board fixing screws 65 (see FIG. 4). As a result, the magnetized surface 162a of the second magnet 162 and the sensor surface 172a of the second magnetism sensing element 172 face each other with a predetermined gap G, and the magnetized surface 162a of the second magnet 162 and the second magnetism sensitive surface. The sensor surface 171a of the element 172 opposes with a predetermined gap.

(Terminal member)
The encoder cable 5 is a shield cable in which a plurality of signal lines are covered with a metal mesh shield. At the end of the encoder cable 5, a frame ground line insulated from the signal line and connected to a shield that covers the signal line is drawn out along with the plurality of signal lines. The frame ground line is electrically connected to the frame ground potential of the motor 3 through a pattern provided on the substrate 60 so as to be insulated from the encoder circuit and the terminal member 9.

As shown in FIGS. 6 and 7, one of the three holder fixing screws 145 for fixing the encoder holder 14 to the first bearing holder 42A overlaps the leg portion 150 of the encoder holder 14 and the terminal member 9. It is a terminal fixing screw 145A that is fixed by fixing. A notch 149 having a shape recessed toward the output side L1 is provided in a portion of the encoder holder 14 on the X2 side of the body 140. One of the three leg portions 150 is arranged on the outer peripheral side of the cutout portion 149, and the terminal member 9 overlaps with the cutout portion 149 and the leg portion 150.

The terminal member 9 is a conductive sheet metal member, and is made of copper in this embodiment. The terminal member 9 includes a fixing portion 91 extending from the cutout portion 149 of the encoder holder 14 to the top of the leg portion 150, and an arm portion 92 extending from the fixing portion 91 to the circuit board assembly 13 side. The fixing portion 91 is provided with a long hole 93 that overlaps with the fixing hole 147 (see FIG. 5) provided in the leg portion 150. The fixing portion 91 includes a head portion and a leg portion 150 of the terminal fixing screw 145A which is a conductive fixing member.
It is sandwiched between the first bearing holder 42A and the leg 150 by the terminal fixing screw 145A. Therefore, the terminal member 9 is electrically connected to the frame ground of the motor case 4 via the terminal fixing screw 145A.

The first through hole 7 is formed in the board 60 at a position aligned with the connector 18 in the circumferential direction. Further, in the substrate holder 50, a second through hole 8 is formed at a position overlapping the first through hole 7 of the substrate 60 in the central axis L direction. The arm portion 92 of the terminal member 9 includes a first portion 94 that extends in the circumferential direction from the fixed portion 91, and a second portion 95 that is bent substantially at a right angle to the first portion 94 and extends to the counter output side L2. When the circuit board set 13 is fixed to the encoder holder 14, the tip portion 96 of the second portion 95 is arranged in the first through hole 7 and the second through hole 8. When the tip portion 96 of the second portion 95 is soldered to the first through hole 7, the terminal member 9 is electrically connected to the land 7 a provided on the edge of the first through hole 7.

As shown in FIGS. 2 and 6, a cable-side connector 6 connected to the connector 18 on the substrate 60 is provided at the end of the encoder cable 5. The cable-side connector 6 includes terminals corresponding to each of the plurality of signal lines and the frame ground line.

As shown in FIG. 8, the connector 18 on the substrate 60 is provided with a plurality of terminal connecting portions 182 arranged in a line in the width direction of the connector 18. One terminal connection portion 182b of the plurality of terminal connection portions 182 is electrically connected to the land 7a provided on the edge of the first through hole 7 via the pattern provided on the substrate 60. .. Further, a part or all of the other terminal connecting portion 182a is connected to the encoder circuit provided on the substrate 60. Here, the pattern that connects the land 7a and the terminal connecting portion 182b is insulated from the encoder circuit and the other terminal connecting portion 182a, and is insulated from the signal ground of the encoder circuit. The first through hole 7 may be a through hole electrically connected to the pattern.

When the cable side connector 6 is connected to the connector 18 on the substrate 60, the terminal corresponding to the frame ground wire of the encoder cable 5 is connected to the terminal connecting portion 182b electrically connected to the land 7a. Therefore, the frame ground wire of the encoder cable 5 is electrically connected to the terminal member 9 soldered to the first through hole 7 via the land 7 a and the pattern on the substrate 60, and via the terminal member 9, It is connected to the frame ground of the motor case 4. On the other hand, the second through hole 8 formed in the substrate holder 50 is slightly larger than the first through hole 7 of the substrate 60, and the terminal member 9 does not contact the edge of the second through hole 8. Therefore, the substrate holder 50 is not electrically connected to the frame ground of the motor case 4 via the terminal member 9.

Thus, in this embodiment, when the encoder cable 5 is connected to the substrate 60, the encoder cable 5 is electrically connected to the frame ground of the motor case 4 simply by inserting the cable side connector 6 into the connector 18 on the substrate 60. Connected. By electrically connecting the encoder cable 5 to the frame ground of the motor case 4, it is possible to enhance the effect of shielding electrical noise that enters from the outside of the encoder cable 5. Therefore, the noise resistance of the encoder 10 can be improved.

(Main effects of this embodiment)
As described above, the encoder 10 of the present embodiment includes the magnet assembly 15 including the magnet holder 19 that rotates integrally with the rotating shaft 2 and the first magnet 161 and the second magnet 162 that are fixed to the magnet holder 19. Prepare The first magnet 161 is magnetized with one north pole and one south pole in the circumferential direction, and faces the first magnetic sensitive element 171, and the second magnet 162 has the north pole and the south pole alternated in the circumferential direction. A plurality of magnets and is opposed to the second magnetic sensing element 172. The magnet assembly 15 and the magnetic poles of the first magnet 161 and the second magnet 162 are arranged such that the angular positions of the magnetic polarization line M1 of the first magnet 161 and the magnetic polarization line M2 of the second magnet 162 do not match. It is manufactured by setting the target position of the magnetic pole of the magnet 162. Therefore, the magnetic polarization line M1 of the first magnet 161 and the magnetic polarization line M2 of the second magnet 162 do not match in angular position.

In this embodiment, in this way, the magnet assembly 15 is manufactured such that the magnetic polarization line M1 of the first magnet 161 and the angular position of M2 of the second magnet 162 do not match. Therefore, since it is difficult for the polarization position shift amount to become 0, it is difficult for the correction amount based on the polarization position shift to be set to either 0 or the maximum value. Therefore, it is possible to correct the outputs of the first magnetic sensing element 171 and the second magnetic sensing element 172 according to the deviation of the position of the magnetized polarization line, and it is possible to prevent the correction amount from largely fluctuating. Therefore, it is possible to prevent the absolute angular position from largely fluctuating.

In the present embodiment, the first magnet 161 and the second magnet 162 are separated from each other in the radial direction, and the magnet holder 19 includes the shield part 193 arranged between the first magnet 161 and the second magnet 162. The magnet assembly 15 aligns the positions of the magnetization polarization line M1 of the first magnet 161 and the magnetization polarization line M2 of the second magnet 162 on the basis of the marking line 198 which is the position reference provided on the shield part 193. Manufactured. In this way, by providing the position reference to the shield part 193 arranged between the first magnet 161 and the second magnet 162, the angular positions of the magnetized polarization lines M1 and M2 can be accurately aligned with the target position. ..

In the present embodiment, the first magnet 161 magnetized with one N pole and one S pole is positioned and fixed to the magnet holder 19 with respect to the marking line 198 that is the position reference, and the second magnet before magnetization is provided. After fixing 162 to the magnet holder 19, the 2nd magnet 162 is magnetized on the basis of the marking line 198. Therefore, when the second magnet 162 is fixed to the magnet holder 19, the magnetized polarization line M2 can be prevented from shifting from the target position. Therefore, the angular position of the magnetic polarization line M2 can be accurately aligned with the target position.

In the present embodiment, the first magnet 161 and the second magnet 162 are positioned at a position where the magnetized surface 162a of the second magnet 162 is projected beyond the magnetized surface 162a of the first magnet 161 and the tip end surface of the shield portion 193. And fix it to the magnet holder 19. In this way, by projecting the second magnet 162 from the shield portion 193, the second magnet 162 can be magnetized after being fixed to the magnet holder 19. Therefore, it is possible to prevent the magnetized polarization line M2 from deviating from the target position when being fixed to the magnet holder 19. Therefore, the angular position of the magnetic polarization line M2 can be accurately aligned with the target position.

In the present embodiment, the magnetized polarization line M of the first magnet 161 is located at an angular position that coincides with the center in the circumferential direction of the N pole region or the S pole region of the second magnet 162. Therefore, since the magnetic polarization lines M1 and M2 are as far apart as possible in the circumferential direction, even if the positions of the magnetic polarization lines M1 and M2 are displaced due to thermal deformation after assembly, the magnetic polarization lines M1 , M2 in the same angular position is unlikely to occur. Therefore, it is possible to avoid a large variation in the correction amount depending on the displacement of the positions of the magnetic polarization lines M1 and M2, and as a result, a large variation in the absolute angular position.

(Modification)
(1) In the above embodiment, the circuit board set 13 includes the board 60 and the board holder 50, the first magnetic sensing element 171 is mounted on the board 60, and the second magnetic sensing element 172 is fixed to the board holder 50. Although connected to the substrate 60 by the flexible wiring board 174, the circuit board set 13 may not have the board holder 50. For example, a structure may be adopted in which the first magnetic sensing element 171 and the second magnetic sensing element 172 are mounted on the substrate 60, and the substrate 60 is brought into contact with and fixed to the encoder holder 14.

(2) The second magnet 162 is magnetized before being fixed to the magnet holder 19, and the second magnet 162 is positioned in the circumferential direction so that the marking line 198 and the magnetization polarization line M2 do not coincide in the circumferential position. Alternatively, a manufacturing method of fixing the second magnet 162 to the magnet holder 19 may be employed.

DESCRIPTION OF SYMBOLS 1... Motor with encoder, 2... Rotating shaft, 3... Motor, 4... Motor case, 5... Encoder cable, 5A... 1st part, 5B... 2nd part, 6... Cable side connector, 7a... Land, 7... 1 through hole, 8... second through hole, 9... terminal member, 10... encoder, 11... encoder case, 12... encoder cover, 13... circuit board assembly, 14... encoder holder, 15... magnet assembly, 16... magnet , 17... Magnetosensitive element, 18... Connector, 19... Magnet holder, 20... Cable guide member, 21... Guide surface, 22... Arc surface, 23... Cable passage, 24... Positioning hole, 41... Cylindrical case, 42A... First bearing holder, 43... Bearing, 44... Circular recess, 45... Flange, 46... Annular wall, 47... Plate, 48... Through hole, 50... Substrate holder, 51... Fixing hole, 52... Boss section, 53... Plane Reference numeral 54, edge portion, 56... through hole, 57... step portion, 58... through hole, 59... shield mounting surface, 60... substrate, 60a... counter output side substrate surface, 60b... output side substrate surface, 61... straight line Part, 61A... Exposed part, 61B... Housing part, 62, 63... Fixing hole, 64... Notch part, 65... Board fixing screw, 66... Positioning pin, 70... Fixing member, 80... Shield member, 90... Bending position , 91... Fixed part, 92... Arm part, 93... Long hole, 94... First part, 95... Second part, 96... Tip part, 100... Jig, 101... Positioning surface, 111... End plate part, 112 ... Side plate part, 113... Wiring take-out part, 114... Seal member, 115... Rib, 116... Convex part, 117... Notch part, 118... Holding member, 119... Encoder cable holder, 121... End plate part, 122... Side plate Part, 123... Opening part, 124... Fixing hole, 125... Fixing member, 126... Dustproof member, 127... Straight part, 128... Bending part, 131... Positioning hole, 132... Fixing hole, 133... Ground through hole, 140... Body part, 141... Magnet arrangement hole, 143... Annular surface, 144... Boss part, 145... Holder fixing screw, 145A... Terminal fixing screw, 146... Positioning hole, 147... Fixing hole, 148... Penetration part, 149... Notch Part, 150... Leg part, 161, 1st magnet, 161a... Magnetization surface, 162... 2nd magnet, 162a... Magnetization surface, 171... 1st magnetic sensing element, 171a... Sensor surface, 172... 2nd magnetism Element, 172a... Sensor surface, 173... Connection terminal, 174... Flexible wiring board, 175... Hall element, 181... Insertion port, 182, 182a, 182b... Terminal connection part, 191... Magnet holder Holding part, 192... Shaft part, 193... Shield part, 193a... Tip surface, 194... Yoke part, 195... Screw hole, 196... Set screw, 197... Shaft hole, 198... Marking line, 471... Notch, 621... Ground through hole, C... Dustproof member disposition region, G... Gap, L... Central axis, L1... Output side, L2... Counter output side, M1... Magnetization polarization line of first magnet, M2... Attachment of second magnet Magnetic polarization line, P... Reference plane

Claims (8)

A magnet holder that rotates integrally with the rotating shaft, and a first magnet and a second magnet that are fixed to the magnet holder,
The first magnet is magnetized with one north pole and one south pole in the circumferential direction, and faces the first magnetic sensing element.
The second magnet is a method of manufacturing a magnet assembly in which a plurality of N poles and S poles are alternately magnetized in the circumferential direction, and the magnet assembly faces the second magnetic sensing element.
The target positions of the magnetic poles of the first magnet and the magnetic poles of the second magnet are set so that the magnetic polarization lines of the first magnet and the magnetic polarization lines of the second magnet do not have the same angular positions. A method for manufacturing a magnet assembly, which comprises setting and manufacturing the magnet assembly. The first magnet and the second magnet are radially separated from each other,
The magnet holder includes a shield portion arranged between the first magnet and the second magnet,
2. The magnet assembly according to claim 1, wherein the positions of the magnetization polarization line of the first magnet and the magnetization polarization line of the second magnet are aligned based on a position reference provided on the shield part. Three-dimensional manufacturing method. Positioning the first magnet magnetized with one N pole and one S pole relative to the position reference and fixing the magnet to the magnet holder,
The method for manufacturing a magnet assembly according to claim 2, wherein after the second magnet before being magnetized is fixed to the magnet holder, the second magnet is magnetized with the position reference as a reference. The first magnet and the second magnet are positioned at a position where the magnetized surface of the second magnet is projected from the magnetized surface of the first magnet and the tip end surface of the shield portion, and the magnet holder is positioned on the magnet holder. The method for manufacturing a magnet assembly according to claim 2, wherein the magnet assembly is fixed. A magnet holder that rotates integrally with the rotating shaft, and a first magnet and a second magnet that are fixed to the magnet holder,
The first magnet is magnetized with one north pole and one south pole in the circumferential direction, and faces the first magnetic sensing element.
The second magnet has a plurality of N poles and S poles alternately magnetized in the circumferential direction, and faces the second magnetic sensing element,
A magnet assembly, wherein the magnetic polarization line of the first magnet and the magnetic polarization line of the second magnet do not match in angular position. The magnet assembly according to claim 5, wherein the magnetized polarization line of the first magnet is positioned at an angular position that coincides with the center of the N pole region or the S pole region of the second magnet in the circumferential direction. .. The first magnet and the second magnet are radially separated from each other,
The magnet holder includes a shield portion arranged between the first magnet and the second magnet,
7. The shield part is provided with a position reference that is located at the same angular position as either the magnetized polarization line of the first magnet or the magnetized polarization line of the second magnet. 6. The magnet assembly according to item 6. A magnet assembly according to any one of claims 5 to 7,
A circuit board set including a board provided with the first magnetic sensing element, the second magnetic sensing element, and an encoder circuit to which signals of the first magnetic sensing element and the second magnetic sensing element are input;
An encoder, comprising: a reference surface on which the circuit board set is mounted; and an encoder holder having a magnet placement hole in which the magnet assembly is placed.

Images