CN111490643B - Encoder and motor with encoder - Google Patents

Encoder and motor with encoder Download PDF

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Publication number
CN111490643B
CN111490643B CN202010052619.2A CN202010052619A CN111490643B CN 111490643 B CN111490643 B CN 111490643B CN 202010052619 A CN202010052619 A CN 202010052619A CN 111490643 B CN111490643 B CN 111490643B
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China
Prior art keywords
encoder
fixing
substrate
holder
terminal
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CN202010052619.2A
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CN111490643A (en
Inventor
上條健
中山裕次
樋口大辅
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Nidec Sankyo Corp
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Nidec Sankyo Corp
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Publication of CN111490643A publication Critical patent/CN111490643A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/20—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection for measuring, monitoring, testing, protecting or switching
    • H02K11/21—Devices for sensing speed or position, or actuated thereby
    • H02K11/215—Magnetic effect devices, e.g. Hall-effect or magneto-resistive elements
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K11/00—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection
    • H02K11/01—Structural association of dynamo-electric machines with electric components or with devices for shielding, monitoring or protection for shielding from electromagnetic fields, i.e. structural association with shields

Abstract

An encoder and a motor with the encoder, which realize standardization of parts for reducing electrical noise on an encoder cable. The encoder is provided with a circuit board group (13) on which a magnetic sensor (17) and a connector (18) are mounted, an encoder holder (14) that supports the circuit board group, and a terminal member (9) that is fixed to a motor case (4) together with the encoder holder. The terminal member is provided with a fixing portion (91) fixed to the motor case by a conductive terminal fixing screw (145A), and an arm portion (92) connected to a pattern for connecting to a frame ground line of a substrate (60) provided in the circuit board group. The fixing portion can move and fix the position of the terminal fixing screw (145A) in the long hole (93), so that the position of the fixing hole (147) on the encoder bracket side can be changed. Therefore, the same shape of terminal parts can be used for different types of motors with encoders, and the parts can be standardized.

Description

Encoder and motor with encoder
Technical Field
The present invention relates to an encoder for detecting rotation of a rotor by a magnetic sensor and a motor with the encoder.
Background
Patent document 1 discloses a motor including an encoder for detecting rotation of a rotor. In the motor of patent document 1, the encoder includes a magnetic sensor mounted on a substrate and a magnet that rotates integrally with an output shaft of the motor. The base plate is supported by an encoder bracket fixed to the motor case. The substrate on which the magnetic sensor is mounted and the magnet are covered with an encoder cover. The encoder cover is fixed to an inner surface of an encoder housing fixed to the motor housing.
Since the encoder mounted on the motor is affected by various noises, the output may be changed depending on the usage environment of the product, and the occurrence of the angle error may also be changed. For example, the output of the magnetic sensor changes due to the influence of magnetic noise or electromagnetic wave noise caused by the disturbance magnetic field. Further, the output of the magnetic sensor and the amplification value of the output of the magnetic sensor constituted by the encoder circuit mounted on the substrate may be affected by electrical noise such as frame ground noise and power supply noise of the motor main body to which the encoder is fixed.
As a countermeasure against such electromagnetic wave noise, patent document 1 discloses using a cover made of a magnetic material such as iron as an encoder cover for covering a substrate, and causing the encoder cover to function as a magnetic shield. Further, the encoder cover is extended to a position where it contacts the motor case, thereby isolating the intrusion of electromagnetic wave noise.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2018-42332
Disclosure of Invention
Technical problem to be solved by the invention
As described above, in patent document 1, the encoder cover is used as a shield, but the encoder cable is connected to the substrate on which the encoder circuit is mounted, and electrical noise such as ESD (electrostatic discharge) and EFT/B (electrical fast transient pulse) is generated in the encoder cable, and thus the electrical noise enters the periphery of the encoder circuit.
Therefore, the following techniques are proposed: electrical noise on the encoder cable is reduced by electrically connecting the encoder cable to the frame ground of the motor. For example, the following techniques are proposed: when the frame ground wire is led out to the end of the encoder cable and the encoder holder supporting the substrate is fixed to the end surface of the motor case by screws, the terminals of the frame ground wire are fastened and fixed together by conductive fixing screws.
In addition, when the space around the substrate and the encoder holder is narrow, the workability of the work of connecting the frame ground lines by screwing is poor. Therefore, the following techniques are proposed: when a terminal connected to a frame ground line is provided on a connector on a substrate, and the terminal is connected to a pattern insulated from an encoder circuit and an encoder holder is screwed to a motor case, a terminal member made of a metal plate is screwed to the encoder holder using a conductive fixing screw. Thus, the end of the terminal member can be connected to the pattern on the substrate only by mounting the substrate on the encoder holder, and the frame ground line and the frame ground of the motor can be electrically connected only by connecting the encoder cable to the connector on the substrate. The applicant of the present application proposed the structure in japanese patent application No. 2017-122935 and japanese patent application No. 2017-147507.
However, when this structure is applied to a plurality of types of motors with encoders, the shape and size of the encoder holder change depending on the type and structure of the motor, and the positional relationship between the fixing screws and the substrate changes. Therefore, since it is necessary to prepare terminal fittings having different shapes and sizes for each type of motor, there is a problem that the parts management becomes complicated and the parts cost increases.
In view of the above problems, an object of the present invention is to standardize components for reducing electrical noise on an encoder cable, and reduce component management time, labor, and component costs.
Technical scheme for solving technical problem
In order to solve the above-described problem, the present invention provides an encoder comprising: a magnet that rotates integrally with a rotating shaft of the motor; a magneto-sensitive element opposed to the magnet; a substrate on which an encoder circuit for inputting a signal of the magnetic sensor is provided and which is provided with a connector; a terminal member electrically connected to a pattern provided on the substrate, the pattern being insulated from the encoder circuit; an encoder support supporting the substrate; and an electrically conductive fixing member that fixes the encoder holder to the motor, wherein the terminal member includes a fixing portion fixed to the encoder holder and an arm portion extending from the fixing portion, a distal end of the arm portion is electrically connected to a frame ground line of an encoder cable connected to the connector via the pattern, the fixing portion is configured to be able to arrange the fixing member at a plurality of positions including a first position and a second position, and the fixing member arranged at any one of the plurality of positions is fixed to the motor together with the encoder holder, thereby being electrically connected to the frame ground of the motor via the fixing member.
In the present invention, the frame ground of the encoder cable is thus electrically connected to the frame ground of the motor using the terminal member. Therefore, the electrical noise on the encoder cable can be reduced, and therefore, the intrusion of the electrical noise into the periphery of the encoder circuit can be suppressed. The end member is fixed at the same time when the encoder holder is fixed to the motor using a conductive fixing member. Therefore, the fixing of the terminal member and the electrical connection to the frame ground are facilitated, and the encoder cable and the frame ground of the motor main body can be electrically connected only by connecting the encoder cable to the connector on the substrate. Therefore, the frame ground of the encoder cable and the frame ground of the motor can be electrically connected by a simple operation. Further, since the terminal block can arrange and fix the fixing block at any one of a plurality of positions, even when the shape and size of the encoder holder are changed and the positional relationship between the fixing block and the substrate is changed, a general-purpose terminal block can be used. Therefore, even for motors of different types, it is possible to standardize the terminal members for reducing the electrical noise on the encoder cable. Therefore, the time for managing the parts, the labor, and the cost of the parts can be reduced.
In the present invention, it is preferable that the fixing portion includes a weak portion or a mark provided between the first position and the second position. Thus, the unnecessary portion can be easily bent or cut according to the change in the position of the fixing member. Therefore, the outer shape of the terminal member can be easily reduced, and therefore, the encoder can be downsized. In the case of cutting the unnecessary portion, the terminal member may be fixed and then cut, or a previously cut terminal member may be fixed. In the case of cutting the unnecessary portion, the cutting step may be performed in a parts manufacturer or may be performed in a step of assembling the encoder.
In the present invention, the fixing portion includes an elongated hole, and the first position and the second position are different positions from each other in the elongated hole. For example, the first position is a position on one end side of the long hole, and the second position is a position on the other end side of the long hole. By providing the long hole in this manner, the fixed position can be easily moved. Further, since the fixed position can be continuously moved, it is possible to flexibly cope with a change in the positional relationship between the substrate and the fixing member. Therefore, the design change of the motor can be flexibly adapted.
In the present invention, it is preferable that the encoder holder includes a positioning portion spaced apart from a position where the fixing member is disposed in a circumferential direction, and the terminal member is positioned at a position where the arm portion contacts the positioning portion. Thus, the positioning of the terminal member is facilitated, and the connection with the substrate is facilitated. Therefore, the mounting work of the terminal member is easy, and the work time can be shortened.
In the present invention, it is preferable that the fixing member is a screw, and the positioning portion is located on a front side of the arm portion in a rotation direction of the screw when the screw is fastened. In this way, the arm portion can be positioned by the operation of screwing the fixing member (screw), and therefore, the positioning operation is easy. In addition, when the arm portion hits against the positioning portion, the terminal member and the fixing member (screw) can be prevented from being rotated together to cause the position of the arm portion to be displaced.
In the present invention, it is preferable that the outer peripheral surface of the encoder holder includes a first flat surface portion located on an inner peripheral side of the fixing member, the positioning portion is a second flat surface portion adjacent to the first flat surface portion in a circumferential direction, the fixing portion includes a first linear portion in contact with the first flat surface portion, and the arm portion includes a second linear portion in contact with the second flat surface portion. Thus, the fixing portion for fixing the motor can be easily positioned, and the arm portion for connecting to the substrate can be easily positioned. Therefore, the mounting work of the terminal member is easy, and the work time can be shortened.
In the present invention, it is preferable that the substrate includes a through hole in which a distal end portion of the arm portion is disposed, the distal end portion being disposed at an end portion of one side of the arm portion in a width direction, the one side of the width direction being a side located on an inner peripheral side of the encoder frame. In this way, by disposing the distal end portion for connection to the encoder circuit on the substrate at the end portion on the inner peripheral side of the arm portion, the through hole for connection to the terminal fitting can be disposed on the inner peripheral side. Therefore, it is not necessary to increase the size of the substrate for connection with the terminal member.
The present invention provides a motor with an encoder, including the encoder and the motor.
(effect of the invention)
According to the present invention, the frame ground of the encoder cable is electrically connected to the frame ground of the motor using the terminal member. Therefore, the electrical noise on the encoder cable can be reduced, and the intrusion of the electrical noise into the surroundings of the encoder circuit can be suppressed. The terminal member is fixed while the encoder holder is fixed to the motor using a conductive fixing member. Therefore, the fixing of the terminal member and the electrical connection to the frame ground are facilitated, and the encoder cable and the frame ground of the motor main body can be electrically connected only by connecting the encoder cable to the connector on the substrate. Therefore, the frame ground of the encoder cable and the frame ground of the motor can be electrically connected by a simple operation. Further, since the terminal block can arrange and fix the fixing member at any one of a plurality of positions, a general-purpose terminal block can be used even when the shape and size of the encoder holder are changed and the positional relationship between the fixing member and the substrate is changed. Therefore, even for motors of different types, it is possible to standardize the terminal members for reducing the electrical noise on the encoder cable. Therefore, the time for managing the parts, the labor, and the cost of the parts can be reduced.
Drawings
Fig. 1 is an external perspective view of a motor with an encoder to which an encoder according to the present invention is applied.
Fig. 2 is an exploded perspective view of the encoder and the first bearing holder viewed from the opposite side to the output side.
Fig. 3 is an exploded perspective view of the encoder and the first bearing holder as viewed from the output side.
Fig. 4 is a sectional view of the encoder, the first bearing holder, and the rotary shaft.
Fig. 5 is an exploded perspective view of the circuit board assembly viewed from the opposite side of the output.
Fig. 6 is an exploded perspective view of the circuit substrate group as viewed from the output side.
Fig. 7 is a perspective view of the encoder and the first bearing holder with the encoder housing and the encoder cover removed.
Fig. 8 is an exploded perspective view of the encoder and the first bearing holder with the encoder case and the encoder cover removed, as viewed from the opposite side of the output.
Fig. 9 is an exploded perspective view of the encoder and the first bearing holder from the output side with the encoder case and the encoder cover removed.
Fig. 10 is an explanatory view of the terminal member.
Fig. 11 is an explanatory diagram showing a grounding structure of a terminal block in a motor with an encoder different from the type of fig. 1.
FIG. 12 is a perspective view of the encoder bracket and end fitting of the version of FIG. 11.
Description of the reference numerals
1 … motor with encoder; 2 … rotating shaft; 2a output shaft; a 3 … motor; 4 … motor housing; 5 … encoder cable; 6 … cable side connector; 7a … pad; 7 … a first through hole; 8 … a second through hole; 9 … end fitting; a 10 … encoder; 11 … encoder housing; 12 … encoder enclosure; 13 … circuit substrate set; 14 … encoder mount; 15 … magnet assembly; 16 … magnet; 17 … magnetic sensing element; an 18 … connector; 19 … magnet holder; 20 … cable guide member; 21 … guide surface; 22 … circular arc surface; 23 … cable channel; 30 … wiring take-out section; 31 … cable holder; 41 … a cylindrical housing; 42a … first bearing retainer; 42B … a second bearing retainer; 43 … bearing; 44 … circular recess; 45 … flange; 46 … annular wall; 47 … plates; 48 … through holes; 50 … a substrate holder; 51 … fixing hole; 52 … boss portion; 53 … planar portion; 54 … rim; 56 … through holes; 57 … step; 58 … through holes; 59 … shield mounting face; a 60 … substrate; 60a … outputs the opposite substrate face; 60b … output side substrate surface; 61 … linear section; 61A … exposed portion; 61B … receiving portion; 62. 63 … fixation holes; 64 … notched portion; 65 … substrate fixing screws; 66 … locating pins; 70 … a securing member; 80 … shielding member; 90 … curved position; 91 … fixed part; 92 … arm; 93a … in a first position; 93B …;93 … elongated holes; 94 … first portion; 95 …;96 …;97 … base end; 98 …;99 … a second linear portion; 111 … end plate portion; 112 …;113 … wiring take-out section; 114 … seal component; 117 … notched portion; 118 … a holding member; 119 … encoder cable mount; 121 … end plate portion; 122 …;123 … opening; 124 … fixation holes; 125 … a securing member; 126 … dust-proof component; 131 … locating hole; 132 …;133 … ground vias; 140 … a body portion; 141 … magnet configuration holes; 142 … recess; 143 … annular face; 144 … boss portion; 145 … bracket fixing screws; 145A … terminal fixing screw; 146 … locating holes; 147 … fixation holes; 149 … a notched portion; 149A …;149B …;150 … legs; 161 … a first magnet; 162 … a second magnet; 171 …;172 … a second magneto-sensitive element; 173 … connection terminal; 174 … a flexible wiring substrate; 175 … hall element; 181 …; 182. 182a, 182b … terminal connection portions; 191 … magnet holding part; 192 … shaft portion; 193 … shield; 194 … yokes; 441 … recess; 442 … annular protrusions; 443 … fixing hole; 621 … ground vias; l … central axis; the output side of L1 …; l2 … opposite output side
Detailed Description
Next, an embodiment of an encoder and a motor with an encoder to which the present invention is applied will be described with reference to the drawings. Fig. 1 is an external perspective view of an encoder-equipped motor 1 including an encoder 10 to which the present invention is applied. Fig. 2 and 3 are exploded perspective views of the encoder 10 and the first bearing holder 42A, fig. 2 is an exploded perspective view viewed from the opposite side to the output side, and fig. 3 is an exploded perspective view viewed from the output side. Fig. 4 is a sectional view of the encoder 10, the first bearing holder 42A, and the rotary shaft 2.
As shown in fig. 1, the encoder-equipped motor 1 includes: a motor 3 having a rotating shaft 2; and an encoder 10 that detects rotation of the rotary shaft 2. In the present specification, three XYZ directions are mutually orthogonal directions, and one of the three directions is X1, Y1, and Z1, and the other is X2, Y2, and Z2. The Z direction is parallel to the central axis L of the rotary shaft 2, and the X direction and the Y direction are orthogonal to the central axis L.
(electric motor)
The motor 3 includes a motor case 4 that houses a rotor and a stator (not shown). The rotor rotates integrally with the rotary shaft 2, and the stator is fixed to the motor case 4. An end portion of the rotary shaft 2 protruding from the motor case 4 to the outside is an output shaft 2a to which a driven member is connected. In the present specification, the direction in which the output shaft 2a protrudes from the motor case 4 is referred to as an output side L1, and the opposite side to the output side L1 is referred to as an opposite-to-output side L2. The encoder 10 is fixed to an end of the opposite-output side L2 of the motor 3.
As shown in fig. 1, the motor case 4 includes a cylindrical case 41 extending in the direction of the center axis L, a first bearing holder 42A fixed to an end portion of the opposite output side L2 of the cylindrical case 41, and a second bearing holder 42B fixed to an end portion of the output side L1 of the cylindrical case 41. The cylindrical housing 41, the first bearing holder 42A, and the second bearing holder 42B are substantially rectangular when viewed along the direction of the center axis L. A side surface of the cylindrical case 41 facing the X1 side is provided with a wiring extraction portion 30. The wiring extraction unit 30 includes a notch (not shown) formed in a side surface of the cylindrical case 41 on the X1 side, and a cable holder 31 fixed to the side surface at a position covering the notch. The motor cable is led out from the inside of the motor case 4 to the inside of the cable holder 31 through the notch of the cylindrical case 41, and is taken out to the outside from the end of the output side L1 of the cable holder 31.
The encoder 10 is fixed to the first bearing holder 42A of the motor housing 4 from the opposite output side L2. As shown in fig. 2, the first bearing holder 42A includes a circular recess 44 recessed toward the output side L1, a flange 45 extending toward the outer periphery of the circular recess 44, and an annular wall 46 projecting toward the opposite-to-output side L2 along the edge of the circular recess 44. The inner peripheral surface of the circular recess 44 is provided with recesses 441 recessed toward the outer peripheral side at three positions at equal angular intervals. The annular wall 46 is provided in a range other than the circumferential position where the recess 441 has been provided.
As shown in fig. 2 and 3, a bearing 43 is held at the bottom center of the circular recess 44. The bearing 43 rotatably supports an end portion of the non-output side L2 of the rotating shaft 2. Further, 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 by three screws.
(encoder)
As shown in fig. 2 to 4, the encoder 10 includes: an encoder case 11 fixed to the first bearing holder 42A, an encoder cover 12 disposed inside the encoder case 11, a circuit board group 13 disposed inside the encoder cover 12, an encoder holder 14 for fixing the circuit board group 13, a magnet assembly 15 disposed on the inner circumferential side of the encoder holder 14, and a cable guide 20 disposed between the encoder case 11 and the encoder cover 12.
As shown in fig. 4, the magnet assembly 15 includes a magnet 16 disposed 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. Accordingly, the magnet 16 rotates integrally with the rotary shaft 2. The circuit board group 13 includes a board holder 50 and a board 60 fixed to the board holder 50. The circuit substrate group 13 includes a magnetic sensor 17 facing the magnet 16 fixed to the rotary shaft 2, and a signal of the magnetic sensor 17 is input to an encoder circuit on the substrate 60. In the present embodiment, an MR element is used as the magneto-sensitive element 17.
(encoder case)
The encoder case 11 includes an end plate portion 111 that is substantially rectangular when viewed along the direction of the center axis L, and a cylindrical 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 take-out section 113 for passing the encoder cable 5 is provided on a side surface of the side plate section 112 facing the X1 side. As shown in fig. 2 and 3, the wiring take-out portion 113 includes a notch 117 formed in the side plate portion 112, a holding member 118 attached to the notch 117, and an encoder cable holder 119 covering the holding member 118 and the notch 117.
The encoder housing 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 screwing fixing screws into the corner portions at three places. In the present embodiment, the encoder housing 11 and the motor housing 4 are made of a nonmagnetic material such as aluminum.
(encoder support)
As shown in fig. 2 and 3, the encoder holder 14 is an annular member having a predetermined thickness (height) in the direction of the central axis L, and a magnet arrangement hole 141 having a circular shape as viewed from the direction of the central axis L is provided at the center thereof. The encoder bracket 14 is fixed to the first bearing holder 42A from the opposite-output side L2 by three bracket fixing screws 145. The first bearing holder 42A is provided with an annular projection 442 lower than the annular wall 46 on the outer peripheral side of the annular wall 46 provided at the edge of the circular recess 44, and the encoder holder 14 abuts against the annular projection 442. When the encoder bracket 14 is fixed to the first bearing holder 42A, the rotary shaft 2 and the magnet assembly 15 are disposed at the center of the magnet disposition hole 141.
A circuit board group 13 is fixed to the encoder bracket 14. As shown in fig. 2, the encoder holder 14 includes a boss portion 144 protruding from the annular surface 143 facing the opposite output side L2 at three locations, and the circuit board group 13 is screwed to the boss portion 144 by three board fixing screws 65. The circuit substrate group 13 is positioned in the direction of the central axis L by touching the front end surface of the boss portion 144 from the opposite-output side L2. By fixing the circuit board group 13 to the encoder holder 14, the magnetic sensor 17 mounted on the circuit board group 13 and the magnet 16 in the magnet assembly 15 face each other with a predetermined gap.
When the circuit board group 13 is fixed to the encoder holder 14, the positioning pins 66 are used to position the circuit board group 13 in the circumferential direction. As shown in fig. 3, the circuit board group 13 includes two positioning holes 131 into which the end portions of the positioning pins 66 are fitted. The positioning holes 131 are disposed on the substrate holder 50. On the other hand, as shown in fig. 2, the encoder holder 14 includes two convex portions protruding toward the opposite output side L2 from the annular surface 143, and each convex portion includes a positioning hole 146 into which an end portion of the positioning pin 66 is fitted. The encoder holder 14 and the circuit substrate group 13 are positioned in the circumferential direction by fitting one end and the other end of the two positioning pins 66 into the positioning holes 146 of the encoder holder 14 and the positioning holes 131 of the circuit substrate group 13, respectively, at two locations separated in the circumferential direction. Since the positioning pins 66 are spring pins, the circuit board group 13 can be positioned while preventing circumferential play.
(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. 2 to 4, the magnet holder 19 includes a substantially disk-shaped magnet holding portion 191 and a cylindrical shaft portion 192 protruding from the center of the magnet holding portion 191 toward the output side L1. The tip of the rotating shaft 2 is fixed to the shaft 192 by any one of press fitting, an adhesive, and a setscrew, or a combination thereof. In the present embodiment, a stopper screw is screwed into a screw hole penetrating the shaft portion 192 in the radial direction, and the rotary shaft 2 disposed in a shaft hole penetrating the center of the shaft portion 192 is fixed from the side. As shown in fig. 2 and 4, the magnet 16 includes a circular first magnet 161 fitted into a recess formed in the center of the magnet holder 191, and an annular second magnet 162 fitted into a step formed on the outer periphery of the first magnet. The first magnet 161 magnetizes one pole N and one pole S in the circumferential direction. On the other hand, the second magnet 162 is magnetized with multipoles of N-poles and S-poles alternately in the circumferential direction.
The magnet holder 19 is made of a magnetic material. 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 positioned on the output side L1 of the second magnet 162 (see fig. 8 and 9). In the magnet assembly 15, the first magnet 161 and the second magnet 162 are separated in the radial direction, and the shield portion 193 is disposed between the first magnet 161 and the second magnet 162. The shield portion 193 is an annular convex portion protruding toward the opposite-to-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.
(encoder cover)
As shown in fig. 2 and 3, the encoder cover 12 includes an end plate portion 121 facing the circuit board group 13 from the side opposite to the magnet 16 (opposite output side L2), and a side plate portion 122 extending from the outer peripheral edge of the end plate portion 121 to the output side L1. As shown in fig. 4, the encoder cover 12 covers the circuit substrate group 13 from the side opposite to the magnet 16 (the opposite output side L2). The side plate portion 122 surrounds the outer periphery of the circuit board group 13 and the outer periphery of the magnetic sensor element 17 mounted on the circuit board group 13. The front end of the side plate portion 122 extends to a position closer to the output side L1 than the circuit board group 13. The encoder cover 12 is positioned in the direction of the center axis L by the tip of the side plate 122 abutting against an annular surface 143 (see fig. 2) of the encoder bracket 14.
The encoder cover 12 includes an opening 123 facing the X2 side. The opening 123 is a notch portion formed by linearly cutting a part of the circumferential direction of the end plate 121 and the side plate 122 on a plane perpendicular to the radial direction. The circuit board group 13 has an X2-side end portion disposed outside the encoder cover 12. Therefore, the substrate 60 includes an exposed portion 61A disposed outside the opening 123 and a receiving portion 61B received in the encoder cover 12. The circuit board group 13 includes a connector 18 disposed in the exposed portion 61A of the substrate 60. By disposing 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.
The encoder cover 12 is fixed to the circuit board group 13 by a conductive fixing member 125. The encoder cover 12 is provided with fixing holes 124 penetrating the end plate 121 at two locations. As shown in fig. 2, the circuit board group 13 is provided with fixing holes 132 at two locations facing the fixing holes 124 of the encoder cover 12. The encoder cover 12 is fixed to the circuit board group 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, 132 are provided at two locations separated in the circumferential direction. The fixing member 125 is a spring pin. By using the spring pin as the fixing member 125, the encoder cover 12 is prevented from wobbling in the circumferential direction. Therefore, the fixing member 125 can position the encoder cover 12 in the circumferential direction.
The fixing member 125 is made of a conductive metal (e.g., SUS: stainless steel). The fixing hole 132 is provided on the substrate 60, and one of the two places is a ground via 133 provided with a pad electrically connected to a signal 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 of the encoder circuit on the substrate 60.
The encoder cover 12 is made of a magnetic material having conductivity, and functions as a shield member. For example, the encoder cover 12 is formed of iron, permalloy, or the like. In the present embodiment, the encoder cover 12 is formed by press working a magnetic metal plate such as SPCC or SPCE. By covering the circuit board group 13 including the magnetic sensor 17 with the encoder cover 12 made of a magnetic material in this manner, magnetic noise and electromagnetic noise such as an interfering magnetic field are absorbed by the magnetic material, and the magnetic sensor 17 and the encoder circuit can be isolated from the magnetic noise and the electromagnetic noise. In addition, the encoder cover 12 is electrically connected to the signal of the encoder circuit via one of the two fixing members 125. In this way, by covering the circuit board group 13 with a member of signal ground potential, it is possible to isolate the magnetic sensor 17 and the encoder circuit from electrical noise such as frame ground noise from the motor case 4.
As will be described later, the circuit board group 13 includes a board holder 50 that covers the board 60 from the output side L1, and the shield member 80 is mounted on the board holder 50 so as to cover the magnetic sensor element 17. The substrate holder 50 and the shield member 80 are made of a conductive metal such as aluminum, and are connected to a signal ground of the encoder circuit. Therefore, since the magnetic sensor 17 and the encoder circuit are isolated from the magnetic body 16, they are isolated from the electrical noise in all directions except the opening 123.
(dust-proof Member)
As shown in fig. 3 and 4, a dust-proof member 126 for closing the opening 123 is disposed between the encoder cover 12 and the substrate 60. The dust-proof member 126 is made of an elastic member, and the dust-proof member 126 is compressed between the end plate portion 121 of the encoder cover 12 and the substrate 60 in a state where the encoder cover 12 is fixed to the circuit substrate group 13. As shown in fig. 3, the dust-proof member 126 is a linear member and linearly extends along the edge of the opening 123. By disposing the dust-proof member 126 in the opening 123, it is possible to suppress the intrusion of conductive foreign matter into the substrate 60.
(Cable guide member)
As shown in fig. 2 and 3, two cable guide members 20 having the same shape are disposed between the encoder housing 11 and the encoder cover 12. In fig. 4, the cable guide member 20 is not shown. The cable guide member 20 includes a guide surface 21 parallel to the XZ surface and an arcuate surface 22 facing the opposite side of the guide surface 21. The two cable guide members 20 are positioned so that the arc surfaces 22 are on the same circle and the guide surfaces 21 face each other in the Y direction, and are fixed to the encoder housing 11. A positioning portion for positioning the two cable guide members 20 in the arrangement shown in fig. 2 and 3 is provided in the end plate portion 111 of the encoder housing 11.
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 housing 11. Therefore, the encoder cover 12 is pressed against the encoder bracket 14 by the elastic restoring force of the cable guide member 20. Therefore, the risk of the encoder cover 12 being displaced from the circuit board group 13 by vibration or the like can be reduced.
The space between the two cable guide members 20 is a cable channel 23 extending in the X-direction. As shown in fig. 4, in the circuit board group 13, the connector 18 is disposed at an end (end on the X2 side) opposite to the wiring extraction portion 113 with respect to the center of the board 60, and the insertion port 181 of the connector 18 faces the opposite side to the wiring extraction portion 113. The encoder cable 5 connected to the connector 18 is led out from the connector 18 to the X2 side, bent in a shape folded back to the X1 side in the X2 side of the connector 18, and passed through the cable passage 23 to the wiring extraction portion 113.
(Circuit Board set)
Fig. 5 is an exploded perspective view of the circuit board group 13 as viewed from the opposite-output side L2, and fig. 6 is an exploded perspective view of the circuit board group 13 as viewed from the output side L1. As shown in fig. 5 and 6, the circuit board group 13 includes a board holder 50, a board 60 that is in contact with the board holder 50 from the opposite-output side L2, a conductive fixing member 70 that fixes the board 60 to the board holder 50, and a shield member 80 that is fixed to the board holder 50 from the output side L1. The base plate 60 is substantially circular when viewed along the central axis L, and the connector 18 is attached to the edge on the X2 side. The connector 18 is disposed along a straight portion 61 obtained by linearly cutting the edge of the substrate 60. The substrate holder 50 has substantially the same shape as the substrate 60 when viewed in the direction of the central axis L, and the substrate 60 and the substrate holder 50 abut against each other in the direction of the central axis L.
The substrate 60 has fixing holes 62 formed at two locations for fixing to the substrate holder 50. The two fixing holes 62 are disposed on opposite sides with respect to the center of the substrate holder 50. One of the two fixing holes 62 is a ground via 621 electrically connected to a signal of the encoder circuit mounted on the substrate 60. In addition, one of the two fixing holes 62 may be a ground via 621. Further, three or more fixing holes 62 may be provided to fix the substrate 60 and the substrate holder 50 at three positions.
The substrate holder 50 includes a planar portion 53 facing the substrate 60, and an edge portion 54 rising from an outer peripheral edge of the planar portion 53 to the opposite output side L2. The flat portion 53 has fixing holes 51 formed at two positions facing the fixing 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 a spring pin as the fixing member 70, the substrate 60 is prevented from shaking with respect to the substrate holder 50. Further, as described above, since the fixing member 70 is formed of a conductive metal such as SUS and one of the fixing holes 62 is the ground through hole 621, when the substrate 60 is mounted on the substrate holder 50 via the fixing member 70, the substrate holder 50 is electrically connected to the signal 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 solder bonding.
The substrate holder 50 has boss portions 52 for inserting the substrate fixing screws 65 formed at three positions corresponding to the boss portions 144 of the encoder holder 14. In the present embodiment, the tip end surface of the non-output side L2 of the boss portion 52 is a contact surface that contacts the substrate 60. Further, an end surface of the output side L1 of the boss portion 52 is an abutment surface that abuts the encoder holder 14.
The substrate 60 has fixing holes 63 formed at three locations facing the boss portion 52. The circuit substrate group 13 is fixed to the encoder bracket 14 by inserting the three substrate fixing screws 65 through the fixing holes 63 of the substrate 60 and the boss portion 52 of the substrate bracket 50, respectively, and screwing the leading ends thereof to the fixing holes 147 of the encoder bracket 14. The encoder holder 14 is made of an insulating material such as resin. Therefore, when the circuit substrate group 13 is fixed to the first bearing holder 42A via the encoder bracket 14, the substrate holder 50 is insulated from the first bearing holder 42A.
The substrate 60 includes an opposite-output-side substrate surface 60a facing the opposite-output side L2 and an output-side substrate surface 60b facing the output side L1. On the opposite-output-side substrate surface 60a, circuit elements constituting an encoder circuit, a connector 18 for connecting the encoder cable 5, a connection terminal 173, and the like are mounted. The connection terminal 173 is disposed on the outer periphery of the substrate 60 and on the opposite side of the connector 18 with respect to the center of the substrate 60. A notch 64 is formed radially outward of the connection terminal 173 on the outer peripheral edge of the substrate 60. As shown in fig. 6, the magnetic sensor 17 includes a first magnetic sensor 171 disposed at the center of the output-side substrate surface 60b, and a second magnetic sensor 172 connected to a connection terminal 173 via a flexible wiring substrate 174. The flexible wiring board 174 is routed to the output side L1 of the substrate 60 through the notch portion 64 of the substrate 60. The first magnetic sensor 171 and the second magnetic sensor 172 each include a ground terminal (not shown) connected to a signal ground of an encoder circuit formed on the substrate 60. Two hall elements 175 are provided on the output-side substrate surface 60b in the vicinity of the first magnetosensitive element 171. The two hall elements 175 are arranged at angular positions separated by 90 degrees with reference to the position of the magneto-sensitive element 17.
A circular through hole 56 is formed in the center of the flat surface portion 53 of the substrate holder 50. Further, a step portion 57 protruding toward the output side L1 is formed on the surface of the output side L1 of the planar portion 53. The stepped portion 57 extends in a band shape from a region surrounding the through hole 56 toward the outer peripheral edge of the flat 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 magnetosensitive element 171 and the hall element 175 are disposed in the through hole 56. In the through hole 58, a second magnetic sensor 172 connected to a connection terminal 173 on the substrate 60 via a flexible wiring board 174 is disposed. The second magnetic sensor element 172 is fixed to the edge of the through hole 58 and mounted on the substrate holder 50.
When the circuit substrate set 13 is fixed to the encoder holder 14, as shown in fig. 4, the first magnetic sensor 171 and the first magnet 161 are opposed to each other, and the second magnetic sensor 172 and the second magnet 162 are opposed to each other. The encoder 10 is assembled such that a predetermined gap is formed between the surface of the output side L1 of the first magnetic sensor element and the first magnet 161 and between the surface of the output side L1 of the second magnetic sensor element 172 and the second magnet 162.
The first magnetic sensor 171, and the two hall elements 175 and the first magnet 161 arranged in the vicinity thereof function as an absolute encoder by determining the output period of the first magnetic sensor 171 obtained by one rotation of the two hall elements 175. On the other hand, the second magnetic sensor 172 and the second magnet 162 obtain outputs of a plurality of cycles by one rotation, and thus function as incremental encoders. The encoder 10 can perform high-resolution and high-precision position detection by processing the outputs of the two sets of encoders.
(Shielding 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 plate material having a size that completely closes the through-hole 56 and the through-hole 58 formed in the step portion 57. The stepped portion 57 includes a shield attachment surface 59 facing the output side L1, and the shield member 80 is fixed to the shield attachment surface 59 via a conductive adhesive. As described above, the shield member 80 is formed of a conductive nonmagnetic metal such as aluminum, like the substrate holder 50. Therefore, the shield member 80 is electrically connected to a signal of the encoder circuit mounted on the substrate 60 via the substrate holder 50.
The shield member 80 covers the first magnetic sensor element 171 disposed in the through hole 56 and the second magnetic sensor element 172 disposed in the through hole 58. Therefore, 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 shielding member 80. By mounting the shield member 80 on the substrate holder 50, the first magnetic sensing element 171 and the second magnetic sensing element 172 are isolated from the motor 3 by the members (the substrate holder 50 and the shield member 80) of the signal ground potential. Therefore, the chassis ground noise, the power supply noise, and the like that surround from the gap with the first magnet 161 and the second magnet 162 can be effectively isolated. The first magnetic sensor element 171 and the second magnetic sensor element 172 face the first magnet 161 and the second magnet 162 via the shield member 80, but the shield member 80 is a non-magnetic metal, and therefore, the function as a magnetic encoder is not impaired while electromagnetic wave noise is well isolated.
(grounding structure of frame ground wire formed by terminal fittings)
Fig. 7 is a perspective view of the encoder 10 and the first bearing holder 42A with the encoder housing 11 removed. Fig. 8 and 9 are exploded perspective views of the encoder 10 and the first bearing holder 42A with the encoder housing 11 removed, fig. 8 is an exploded perspective view viewed from the opposite output side L2, and fig. 9 is an exploded perspective view viewed from the output side L1. As shown in fig. 8 and 9, the encoder bracket 14 is provided at three positions with fixing holes 147 for passing bracket fixing screws 145 therethrough. One of the three bracket fixing screws 145 is a terminal fixing screw 145A for fixing the encoder bracket 14 and the end fitting 9 in an overlapping manner. As shown in fig. 8, fixing holes 443 are formed in the annular projection 442 of the first bearing holder 42A at three positions overlapping the fixing holes 147.
A notch 149 having a shape recessed toward the output side L1 is provided in the X2 side portion of the encoder bracket 14, and one of the fixing holes 147 is provided in the notch 149. Terminal fitting 9 and terminal fixing screw 145A are disposed in notch 149. When the encoder bracket 14 is fixed to the motor case 4, the fixing portion 91 of the end fitting 9 is disposed to overlap the fixing hole 147 of the notched portion 149, and the fixing portion 91 is fixed to the first bearing holder 42A together with the encoder bracket 14 using one of the bracket fixing screws 145 (terminal fixing screw 145A). Thereby, the fixing portion 91 is sandwiched and fixed between the encoder bracket 14 and the head of the terminal fixing screw 145A. Terminal fitting 9 and terminal fixing screw 145A are conductive members. Therefore, the terminal fitting 9 is electrically connected to the first bearing holder 42A via a terminal fixing screw 145A as a conductive fixing member. Therefore, the terminal member 9 is electrically connected to the frame ground of the motor case 4.
The terminal member 9 is a conductive sheet metal member, and in the present embodiment, is made of copper. The terminal member 9 includes a fixing portion 91 fixed to the notch portion 149 of the encoder holder 14 by screws, and an arm portion 92 extending from the fixing portion 91 toward the circuit board group 13. The arm portion 92 includes a first portion 94 extending in the circumferential direction from the fixed portion 91, and a second portion 95 bent at substantially right angles to the first portion 94 and extending toward the opposite-to-output side L2. The fixing portion 91 is provided with a long hole 93 extending in a direction intersecting the first portion 94 of the arm portion 92. The terminal fixing screw 145A is disposed at one end of the elongated hole 93, and fixes a portion of the fixing portion 91 on the side connected to the arm portion 92 to the motor case 4 together with the encoder bracket 14.
Fig. 10 is an explanatory view of the terminal member 9. Fig. 10 (a) shows a shape when the fixing portion 91 is used without being bent, fig. 10 (b) shows a shape when the fixing portion 91 is used with being bent, and fig. 10 (c) shows a shape when the unnecessary portion of the fixing portion 91 is cut off and used. In the present embodiment, as shown in fig. 7 to 9, an end fitting 9 is used in which the fixing portion 91 is deformed into a shape shown in fig. 10 (b). The fixing portion 91 is bent at a substantially right angle at a halfway position of the long hole 93, and a side not connected to the arm portion 92 is bent into a shape facing the non-output side L2. This can prevent the end of the fixing portion 91 from protruding from the notch 149 to the outer peripheral side and interfering with the encoder housing 11.
The end fitting 9 has a shape capable of disposing and fixing the terminal fixing screw 145A at an arbitrary position in the elongated hole 93. In the present embodiment, the end fitting 9 is fixed to the encoder holder 14 by the end fixing screw 145A disposed at the first position 93A, which is the end portion of the elongated hole 93 on the arm portion 92 side. In this case, since the end portion of the fixing portion 91 opposite to the first position 93A is an unnecessary portion, the unnecessary portion is bent and used as shown in fig. 10 (b). The end fitting 9 can be bent at a bending position 90 shown in fig. 10 (a) and 10 (b). Alternatively, as shown in fig. 10 (c), the fixing portion 91 may be cut at the bending position 90. By assembling the terminal fitting 9 having a shape shown in fig. 10 (c) by cutting off an unnecessary portion (excess portion) in advance, it is possible to avoid interference between the encoder case 11 and the terminal fitting 9.
The end fitting 9 is positioned at a position where the fixing hole 147 provided in the notched portion 149 overlaps the long hole 93. When the encoder bracket 14 has the shape shown in fig. 7 to 9, the fixing hole 147 overlaps the end portion of the elongated hole 93 on the arm portion 92 side, and therefore the terminal fixing screw 145A is disposed at the first position 93A which is the end portion of the elongated hole 93 on the arm portion 92 side. Since the fixing portion 91 of the end fitting 9 includes the elongated hole 93, even when the position of the fixing hole 147 is changed, the end fitting 9 can be used without changing the shape of the end fitting 9 as long as the position of the fixing hole 147 is within a range overlapping with the elongated hole 93. For example, as will be described later, when the fixing hole 147 is provided at a position on the outer peripheral side of the position shown in fig. 8, the terminal fixing screw 145A may be disposed by being moved to a position different from the first position 93A, and the end fitting 9 may be fixed.
The substrate 60 has a first through-hole 7 formed therein at a position circumferentially aligned with the connector 18. 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 direction of the central axis L. The end fitting 9 extends to a position where a first portion 94 extending from the fixing portion 91 in the circumferential direction of the encoder holder 14 overlaps the first through hole 7 and the second through hole 8 in the central axis L direction. The second portion 95 extends from the tip of the first portion 94 in the direction of the central axis L toward the first through hole 7 and the second through hole 8. A tip end portion 96 of the second portion 95 on the non-output side L2 is thinner than a base end portion 97 of the second portion 95, and extends from one end portion of the base end portion 97 in the width direction toward the non-output side L2. The distal end portion 96 has a fineness enough to be inserted into the first through-hole 7.
The notch 149 is formed by cutting the encoder holder 14 with a plane intersecting the radial direction. The cutout portion 149 includes a first flat portion 149A extending in parallel with the linear portion 61 of the substrate 60 and a second flat portion 149B adjacent to the first flat portion 149A in the circumferential direction. The first flat surface portion 149A is provided on the inner peripheral side of the fixing hole 147. The second flat surface portion 149B forms an obtuse angle with the first flat surface portion 149A, and is provided in a range including circumferential positions where the first through-hole 7 and the second through-hole 8 are provided.
The first flat surface portion 149A is disposed on the inner peripheral side of the outer peripheral edge of the circuit board group 13. Therefore, as shown in fig. 7, a part of the terminal fixing screw 145A is covered by the outer peripheral portion of the circuit board group 13 from the opposite output side L2. The other two holder fixing screws 145 are disposed in the recess 142 of the encoder holder 14, and are covered with the outer peripheral portion of the circuit board group 13 from the opposite output side L2, similarly to the terminal fixing screws 145A. The second flat surface 149B is disposed on the inner peripheral side of the first through-hole 7 and the second through-hole 8. That is, the encoder holder 14 is shaped by cutting out the portions that close the first through hole 7 and the second through hole 8 from the output side L1.
When the end member 9 is fixed to the motor case 4, the first flat surface portion 149A and the second flat surface portion 149B of the encoder holder 14 function as positioning portions for positioning the end member 9. The terminal member 9 includes a first linear portion 98 provided on the edge of the fixing portion 91 and a second linear portion 99 provided on the edge of the first portion 94 of the arm portion 92. As shown in fig. 10 (a), the fixing portion 91 has a substantially oblong shape. The first straight portion 98 is provided on the outer peripheral edge of one end side in the longitudinal direction of the fixing portion 91, and linearly extends in a direction orthogonal to the longitudinal direction of the long hole 93. The arm portion 92 extends from a portion of the fixing portion 91 on the side where the first straight portion 98 is provided, in a direction forming an obtuse angle with the first straight portion 98. The second straight portion 99 is provided at an edge of the first portion 94 on the side of the first straight portion 98.
When the end member 9 is positioned on the encoder holder 14, the fixing hole 147 of the encoder holder 14 and the long hole 93 of the end member 9 are made to coincide, the first straight line portion 98 is made to contact the first flat surface portion 149A of the encoder holder 14, and the second straight line portion 99 is made to contact the second flat surface portion 149B. Thereby, the fixing portion 91 is positioned at a position where the long hole 93 and the fixing hole 147 of the encoder bracket 14 overlap. At this time, the fixing hole 147 overlaps with the region (first position 93A) on the arm portion 92 side in the long hole 93. In addition, the arm portion 92 is positioned by contact with the second flat surface portion 149B (positioning portion) at a position circumferentially separated from the fixing portion 91. The second flat surface portion 149B (positioning portion) is located on the front side of the arm portion 92 in the rotation direction of the terminal fixing screw 145A. Therefore, by tightening the terminal fixing screw 145A, the arm portion 92 can be brought into contact with the second flat surface portion 149B. In addition, the end fitting 9 can be prevented from rotating together with the terminal fixing screw 145A and from being positionally displaced with respect to the arm portion 92.
When the arm portion 92 is positioned by contact with the second flat surface portion 149B (positioning portion), the leading end portion 96 of the second portion 95 protrudes to the opposite-output side L2 along the second flat surface portion 149B. The distal end portion 96 of the second portion 95 is disposed on one side in the width direction of the proximal end portion 97 of the second portion 95. The side on which the distal end portion 96 is disposed (the side in the width direction) is the side located on the inner peripheral side of the encoder holder 14. The distal end portion 96 is disposed at a position overlapping the first through hole 7 and the second through hole 8 of the circuit board group 13 when viewed from the center axis L direction. Therefore, when the circuit board group 13 is fixed to the encoder holder 14, the tip portion 96 of the arm portion 92 of the terminal fitting 9 protrudes from the substrate 60 to the opposite output side L2 through the first through hole 7 and the second through hole 8 of the circuit board group 13.
The substrate 60 includes a pad 7a formed at an edge of the first through hole 7. In the present embodiment, the land 7a is provided on the non-output-side substrate surface 60a of the substrate 60, and the ring-shaped land 7a is provided along the edge of the first through hole 7. When the tip end portion 96 of the arm portion 92 of the terminal member 9 is soldered in the first through hole 7, the terminal member 9 is electrically connected to the pad 7a provided at the edge of the first through hole 7.
The encoder cable 5 (see fig. 4) is a shielded 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 lines and connected to a shield covering the signal lines is led out in parallel with the plurality of signal lines. A cable-side connector 6 (see fig. 4) connected to the connector 18 on the board 60 is provided at an end of the encoder cable 5. The cable-side connector 6 includes terminals corresponding to the plurality of signal lines and the chassis ground line.
As shown in fig. 5, a plurality of terminal connecting portions 182 are provided in a row in the width direction of the connector 18 on the board 60. The terminal connecting portion 182b (see fig. 5) at one of the plurality of terminal connecting portions 182 is electrically connected to the land 7a provided at the edge of the first through hole 7 via a pattern provided on the substrate 60. In addition, a part or all of the other terminal connecting portion 182a (see fig. 5) is connected to an encoder circuit provided on the substrate 60. Here, the pattern of the connection pad 7a and the terminal connection portion 182b is insulated from the encoder circuit and the other terminal connection portion 182a, and 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 line of the encoder cable 5 is connected to the terminal connection portion 182b electrically connected to the pad 7a. Therefore, the frame ground line of the encoder cable 5 is electrically connected to the terminal fitting 9 soldered to the first through hole 7 via the pad 7a and the pattern on the substrate 60, and is connected to the frame ground of the motor case 4 via the terminal fitting 9. On the other hand, the second through hole 8 formed in the substrate holder 50 is larger than the first through hole 7 of the substrate 60 by one turn, and the terminal fitting 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 fitting 9.
In this way, in the present embodiment, when the encoder cable 5 is connected to the board 60, the encoder cable 5 is electrically connected to the frame ground of the motor case 4 by inserting the cable-side connector 6 into the connector 18 on the board 60. By electrically connecting the encoder cable 5 to the frame ground of the motor case 4, the effect of shielding the electrical noise entering from the outside of the encoder cable 5 can be improved. Therefore, the noise immunity of the encoder 10 can be improved.
(grounding structure of terminal parts in different types of encoder-equipped motors)
Fig. 11 is an explanatory diagram of a grounding structure of a terminal member in a motor with an encoder of a type different from that of fig. 1. Fig. 12 is a perspective view of the encoder bracket 14 and the end fitting 9 of the embodiment of fig. 11. In the embodiment shown in fig. 11, the end fitting 9 is used as shown in fig. 10 (a), and the end fixing screw 145A is disposed at a second position 93B different from the first position 93A to fix the end fitting 9.
In the embodiment shown in fig. 11, the encoder holder 14 includes a main body 140 formed with a circular magnet arrangement hole 141, and a leg portion 150 protruding from the main body 140 toward the outer peripheral side. The legs 150 are formed at three places at equal angular intervals in the circumferential direction. In the embodiment shown in fig. 11, the first bearing holder 42A has a larger outer shape as viewed from the direction of the center axis L than the first bearing holder in the embodiment shown in fig. 7 to 9, and the encoder holder 14 is disposed inside the circular recess 44 of the first bearing holder 42A. A plate 47 that presses the outer peripheral portion of a bearing (not shown) is disposed at the bottom of the circular recess 44. The leg 150 of the encoder bracket 14 is disposed in a notch 471 provided at the outer periphery of the plate 47. The encoder bracket 14 abuts with the first bearing holder 42A in the central axis L direction via the leg portion 150. The encoder bracket 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 three bracket fixing screws 145. Therefore, the leg portions 150 at three places are provided with fixing holes 147 through which the bracket fixing screws 145 pass.
In the embodiment shown in fig. 11, the encoder holder 14 has a notch 149 formed by cutting the main body 140 with a plane intersecting with the radial direction. Notch 149 includes first flat part 149A and second flat part 149B, as in the embodiment shown in fig. 7 to 9. Therefore, the terminal member 9 is positioned by bringing the first linear portion 98 into contact with the first flat surface portion 149A and the second linear portion 99 into contact with the second flat surface portion 149B, and is fixed to the first bearing holder 42A together with the encoder holder 14 by the conductive terminal fixing screw 145A. The connection between the tip end 96 of the arm portion 92 of the terminal fitting 9 and the pad 7a provided on the substrate 60 is performed in the same manner as in the above-described embodiment.
One of the three leg portions 150 is arranged substantially at the center in the circumferential direction of the first flat surface portion 149A. In the fixing portion 91 of the terminal fitting 9, a portion on the arm portion 92 side overlaps the notched portion 149, and a portion on the opposite side of the arm portion 92 overlaps the leg portion 150. As shown in fig. 12, the fixing hole 147 provided to the leg portion 150 overlaps with an end portion of the long hole 93 on the opposite side to the first position 93A (i.e., an end portion of the long hole 93 on the arm portion 92 side). Therefore, in the present embodiment, the terminal fixing screw 145A is disposed at a second position 93B different from the first position 93A. In the present embodiment, the fixing portion 91 does not protrude from the notch portion 149 and the upper portion of the leg portion 150, and therefore, it is not necessary to bend and cut unnecessary portions.
The grounding structure of the terminal member 9 can be applied to the form of the encoder holder 14 in which the fixing hole 147 is disposed at an arbitrary position between the first position 93A and the second position 93B. That is, the end fitting 9 can be fixed to the motor case 4 together with the encoder holder 14 by disposing the end fixing screw 145A at any one of a plurality of positions including the first position 93A and the second position 93B in the elongated hole 93.
(main effects of the present embodiment)
As described above, the encoder-equipped motor 1 of the present embodiment includes the encoder 10 and the motor 3, and the encoder 10 includes: a magnet 16 that rotates integrally with the rotary shaft 2, a magnetic sensor 17 that faces the magnet 16, a circuit board group 13 on which the magnetic sensor 17 and a connector 18 are mounted, a terminal member 9 that is electrically connected to a pattern provided on a substrate 60 of the circuit board group 13 in an insulated manner from an encoder circuit, an encoder holder 14 that supports the circuit board group 13, and a conductive terminal fixing screw 145A that fixes the encoder holder 14 to a first bearing holder 42A of the motor case 4. The terminal member 9 includes a fixing portion 91 fixed to the encoder holder 14 and an arm portion 92 extending from the fixing portion 91, and the tip of the arm portion 92 is electrically connected to a chassis ground line of the encoder cable 5 connected to the connector 18 on the substrate 60 via the pattern on the substrate 60. The fixing portion 91 can dispose the terminal fixing screw 145A at any one of a plurality of positions including the first position 93A and the second position 93B, and can be fixed to the motor case 4 together with the encoder bracket 14 by the terminal fixing screw 145A disposed at any one of the plurality of positions. Thereby, the terminal fitting 9 is electrically connected to the frame ground of the motor 3 via the terminal fixing screw 145A.
In this way, since the circuit board group 13 is fixed to the motor 3 via the insulating encoder bracket 14, the circuit board group 13 is insulated from the motor 3. In addition, the frame ground of the encoder cable 5 and the frame ground of the motor 3 can be electrically connected using the terminal fitting 9. This can reduce the electrical noise in the encoder cable 5, and thus can suppress the intrusion of the electrical noise into the periphery of the encoder circuit. When the encoder holder 14 is fixed to the motor using the conductive terminal fixing screw 145A, the terminal member 9 is fixed at the same time. Therefore, since the fixing of the terminal fitting 9 and the electrical connection to the frame ground are easy, the frame ground line of the encoder cable 5 and the frame ground of the motor can be reliably electrically connected by a simple operation. Further, since the terminal fitting 9 has a shape that allows the terminal fixing screws 145A to be arranged and fixed at any one of a plurality of positions, the terminal fitting 9 can be used in a general purpose form even when the shape and size of the encoder bracket 14 change and the positional relationship between the fixing holes 147 in which the terminal fixing screws 145A are arranged and the circuit board group 13 changes. Therefore, even in motors with encoders of different types, standardization of the terminal fitting 9 for reducing electrical noise on the encoder cable 5 can be achieved. Therefore, the time for managing the parts, the labor, and the cost of the parts can be reduced.
In the present embodiment, the fixing portion 91 of the end fitting 9 can be bent or cut at the bending position 90 between the first position 93A and the second position 93B. Therefore, as shown in fig. 7, when the terminal fixing screw 145A is disposed and fixed at the first position 93A, an unnecessary portion on the second position 93B side can be bent. Alternatively, the unnecessary portion may be cut instead of bent. This can easily reduce the outer shape of the terminal member 9, and thus can cope with the downsizing of the encoder 10.
Further, it is preferable to provide a weak portion such as a thin portion, a notch, or the like at the bending position 90. This enables the unnecessary portion to be easily bent or cut, and therefore, the external shape of the terminal fitting 9 can be easily reduced. Therefore, the encoder 10 can be miniaturized, and can be easily applied to motors 1 with encoders of different types. Further, the mark may be provided without providing the weak portion at the bending position 90. This makes it possible to bend or cut the unnecessary portion at an appropriate position.
In the present embodiment, the fixing portion 91 includes the elongated hole 93, and the terminal fixing screw 145A is disposed at a position on one end side of the elongated hole 93 at the first position 93A, and the terminal fixing screw 145A is disposed at a position on the other end side of the elongated hole 93 at the second position 93B. By providing the long hole 93 in this manner, the fixed position can be easily moved. Further, since the fixed position can be continuously moved, it is possible to flexibly cope with a change in the positional relationship between the circuit board group 13 and the terminal fixing screw 145A. Therefore, the design change of the encoder-equipped motor 1 can be flexibly coped with.
In addition, a plurality of holes may be provided in the fixing portion 91 instead of the long hole 93. In addition, instead of providing the fixing portion 91 with an elongated hole, a notch extending linearly may be provided. Even with this configuration, since the terminal fixing screws 145A can be arranged at a plurality of positions, the universal terminal fitting 9 can be used even when the positional relationship between the fixing holes 147 and the circuit board group 13 changes, as in the present embodiment.
In the present embodiment, the encoder holder 14 includes a fixing hole 147 in which the terminal fixing screw 145A is disposed and a second flat surface portion 149B which is a positioning portion circumferentially separated from the fixing hole 147, and the end member 9 is positioned at a position where the fixing portion 91 overlaps the fixing hole 147 and the arm portion 92 contacts the second flat surface portion 149B. By providing the positioning portion in the encoder holder 14 in this manner, the positioning of the terminating member 9 and the connection to the substrate 60 can be easily performed. Therefore, the mounting work of the terminal fitting 9 is easy, and the work time can be shortened.
In the present embodiment, the second flat surface portion 149B as the positioning portion is located on the front side of the rotation direction of the terminal fixing screw 145A when the terminal fixing screw 145A is fastened with respect to the arm portion 92. With such an arrangement, the arm 92 can be positioned by tightening the terminal fixing screw 145A, and therefore the positioning operation of the terminal fitting 9 is facilitated. Further, when the arm portion 92 comes into contact with the second flat surface portion 149B, the position of the arm portion 92 can be prevented from being displaced by the co-rotation of the terminal fixing screw 145A and the terminal fitting 9.
In the present embodiment, the outer peripheral surface of the encoder holder 14 includes a first flat surface portion 149A located on the inner peripheral side of the fixing hole 147 in which the terminal end fixing screw 145A is disposed, a second flat surface portion 149B as a positioning portion is adjacent to the first flat surface portion 149A in the circumferential direction, the fixing portion 91 includes a first straight portion 98 that contacts the first flat surface portion 149A, and the arm portion 92 includes a second straight portion 99 that contacts the second flat surface portion. Therefore, the fixing portion 91 for fixing to the encoder holder 14 and the arm portion 92 for connecting to the circuit substrate group 13 can be easily positioned. Therefore, the mounting work of the terminal fitting 9 is easy, and the work time can be shortened.
In the present embodiment, the circuit board group 13 includes the first through hole 7 in which the distal end portion 96 of the arm portion 92 is disposed. The distal end portion 96 is disposed at one end portion in the width direction of the arm portion 92, and the side on which the distal end portion 96 is disposed is the side located on the inner circumferential side of the encoder frame 14. By providing the distal end portion 96 for connection to the encoder circuit on the substrate 60 at the end portion on the inner peripheral side of the encoder holder 14 in this manner, the first through hole 7 and the second through hole 8 for connection to the terminal fitting 9 can be arranged on the inner peripheral side. Therefore, it is not necessary to enlarge the circuit board group 13 for connection with the terminal unit 9.
(modification example)
In the above embodiment, the circuit board group 13 includes the substrate 60 and the substrate holder 50, the first magnetic sensor element 171 is mounted on the substrate 60, and the second magnetic sensor element 172 is fixed to the substrate holder 50 and connected to the substrate 60 via the flexible wiring board 174, but the circuit board group 13 may be configured without the substrate holder 50. For example, the first magnetic sensor 171 and the second magnetic sensor 172 may be mounted on the substrate 60, and the substrate 60 may be abutted against and fixed to the encoder holder 14.

Claims (4)

1. An encoder, characterized by having:
a magnet that rotates integrally with a rotating shaft of the motor;
a magneto-sensitive element opposed to the magnet;
a substrate on which an encoder circuit for inputting a signal of the magnetic sensor is provided and which is provided with a connector;
a terminal member electrically connected to a pattern provided on the substrate, the pattern being insulated from the encoder circuit;
an encoder support supporting the substrate; and
a conductive fixing member that fixes the encoder bracket to the motor,
the terminal member includes a fixing portion fixed to the encoder holder and an arm portion extending from the fixing portion,
the leading end of the arm portion is electrically connected to a chassis ground line of an encoder cable connected to the connector via the pattern,
the fixing portion is capable of disposing the fixing member at a plurality of positions including a first position and a second position, and is fixed to the motor together with the encoder bracket by the fixing member disposed at any one of the plurality of positions, thereby being electrically grounded to a frame of the motor via the fixing member,
the encoder holder includes a positioning portion circumferentially spaced apart from a position where the fixing member is disposed,
the arm portion of the terminating member is positioned by the positioning portion,
the fixing part is a screw which is provided with a screw head,
the positioning portion is located on a front side of the arm portion with respect to a rotation direction of the screw when the screw is fastened,
the outer peripheral surface of the encoder holder includes a first flat surface portion located on the inner peripheral side of the fixing member,
the positioning portion is a second flat portion that forms an obtuse angle with the first flat portion and is adjacent to the first flat portion in the circumferential direction,
the fixing portion includes a first straight portion facing the first flat portion,
the arm portion includes a second linear portion opposed to the second flat portion,
the second straight portion of the arm portion extends from a portion on a side where the first straight portion is provided toward a direction forming an obtuse angle with the first straight portion,
the fixing portion is provided with a long hole,
the first position and the second position are different positions from each other within the elongated hole,
the fixing portion includes a weak portion or a mark provided between the first position and the second position.
2. The encoder according to claim 1,
the substrate is provided with a through hole for disposing the front end of the arm,
the distal end portion is disposed at an end portion on one side in a width direction of the arm portion, the one side in the width direction being a side located on an inner peripheral side of the encoder frame.
3. The encoder according to claim 1,
the long hole has a longitudinal direction extending in a direction orthogonal to the first straight line portion.
4. An electric motor with an encoder, comprising:
the encoder of any one of claims 1 to 3; and
the motor.
CN202010052619.2A 2019-01-25 2020-01-17 Encoder and motor with encoder Active CN111490643B (en)

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