JP2012068049A - Magnetic type absolute encoder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the detection accuracy and reliability of magnetic type absolute encoders that detect the rotational positions of motors having electromagnetic brakes.SOLUTION: A magnetic type absolute encoder 20 has a multi-polar magnetic encoder 21 provided with two pairs of Hall elements 31 to 34 and a bipolar magnetic encoder 22 provided with two pairs of Hall elements 41 to 44 and is arranged adjacent to an electromagnetic brake 9; noise attributable to magnetic flux leaks from the bipolar magnetic encoder 22 and the electromagnetic brake 9 is removed by synthesizing detection signals of the Hall elements 31 to 34 and noise attributable to magnetic flux leaks from the electromagnetic brake 9 is removed by synthesizing detection signals of the Hall elements 41 to 44 thereby to secure a high accuracy of detection; occurrence of any abnormality is monitored by comparing the rotational positions of motor rotation shafts calculated from the detection signals of multi-polar and bipolar magnetic encoders; and the reliability of detecting actions is thereby ensured.

Description

  The present invention relates to a magnetic absolute encoder that detects the absolute position and the number of rotations within one rotation of a rotating shaft using two sets of magnetic encoders. More specifically, the present invention relates to a magnetic absolute encoder that is assembled to a portion of the motor rotation shaft adjacent to the electromagnetic brake in order to detect the rotation position of the motor rotation shaft of the motor with the electromagnetic brake.

  As a magnetic absolute encoder for accurately detecting the absolute position of the rotating shaft, one using two sets of magnetic encoders is known. Patent Document 1 proposes a magnetic absolute encoder using a 2-pole magnetic encoder and a 64-pole magnetic encoder. Patent Document 2 discloses a magnetic absolute capable of performing high-precision absolute position detection without being affected by the resolution and accuracy of a 2-pole magnetic encoder using a 2-pole magnetic encoder and a multi-pole magnetic encoder. An encoder has been proposed. On the other hand, Patent Document 3 proposes a magnetic absolute encoder with high reliability that can perform detection operation at high speed and high accuracy during normal operation and can continue detection operation with low power consumption during backup.

Japanese Utility Model Publication No. 06-10813 International Publication WO2008 / 136053 Pamphlet JP 2008-180698 A

  Such a magnetic absolute encoder is used to detect the rotational position of a rotating shaft of a motor used in a positioning system or the like. As a motor used in a positioning system or the like, a motor provided with an electromagnetic brake for holding a motor rotation shaft positioned at a target rotation position at the position is used. A magnetic absolute encoder used for a motor with an electromagnetic brake is affected by a leakage magnetic flux caused by the electromagnetic brake, and there is a possibility that the detection accuracy is lowered. In addition, since the two magnetic encoders of the magnetic absolute encoder are arranged in a limited installation space inside the motor, the detection accuracy of the other magnetic encoder may be reduced by the leakage magnetic flux from the magnet of one magnetic encoder. There is. Furthermore, in order to improve the positioning reliability, it is desirable that a backup detection system is provided and a system error can be detected as disclosed in Patent Document 3 described above.

  In view of the above, an object of the present invention is to propose a highly reliable magnetic absolute encoder used for accurately detecting the rotational position of the motor rotation shaft of a motor with an electromagnetic brake.

In order to solve the above problems, the present invention is a magnetic absolute encoder that is disposed adjacent to an electromagnetic brake for restraining rotation of a motor rotation shaft and used to detect the rotation position of the motor rotation shaft. ,
A two-pole magnet fixed coaxially to the motor rotating shaft and having a pair of magnetic pole pairs formed on a circular outer peripheral surface;
Along with the rotation of the two-pole magnet, one pole-side A-phase signal, two-pole-side B-phase signal, and two-pole-side A (−) phase that is an inverted signal of the two-pole-side A-phase signal per rotation. Four bipolar-side magnetic sensing elements arranged to obtain a signal and a two-pole B (-) phase signal that is an inverted signal of the two-pole B-phase signal;
A multipolar magnet fixed coaxially at a position adjacent to the two-pole magnet on the motor rotation shaft and having S pairs of magnetic pole pairs (S: an integer of 2 or more) formed on a circular outer peripheral surface;
At least four multipole-side magnetic detection elements arranged to obtain a pair of multipole-side A-phase signals and a pair of multi-pole-side B-phase signals with an S period per rotation in accordance with the rotation of the multipole magnet;
A multipole-side signal synthesis circuit that synthesizes the signals obtained from the multipole-side magnetic detection element to generate a multipole-side A-phase synthesized signal and a multi-pole-side B-phase synthesized signal;
A two-pole-side signal combining circuit that combines the signals obtained from the two-pole-side magnetic detection element to generate a two-pole-side A-phase combined signal and a two-pole-side B-phase combined signal;
The two-pole-side signal synthesis circuit adds the two-pole-side A-phase signal and the two-pole-side A (−)-phase signal, thereby causing noise due to leakage magnetic flux from the electromagnetic brake included in these signals. By removing the component and adding the two-pole side B-phase signal and the two-pole side B (−) phase signal, the noise component caused by the leakage magnetic flux from the electromagnetic brake contained in these signals is removed. ,
The multipole-side signal synthesis circuit adds the pair of multipole-side A-phase signals to remove noise components due to leakage magnetic flux from the two-pole magnets included in these signals, and By adding the other inverted signal to one of the multipolar A phase signals, the noise component due to leakage magnetic flux from the electromagnetic brake contained in these signals is removed, and the pair of multipolar B phases By adding the signals, the noise component due to the leakage magnetic flux from the two-pole magnet contained in these signals is removed, and the other inverted signal is added to one of the pair of multipolar B-phase signals. Thus, a noise component due to leakage magnetic flux from the electromagnetic brake included in these signals is removed.

Here, the magnetic absolute encoder of the present invention is
Sampling the multi-pole side A-phase composite signal and the multi-pole side B-phase composite signal in a first detection period, and a multi-pole side one-turn absolute value representing an absolute position within one turn of the motor rotation shaft, and A main arithmetic circuit that calculates a multi-pole multi-rotation value representing the number of rotations from a predetermined origin of the motor rotation shaft;
The two-pole side A-phase composite signal and the two-pole side B-phase composite signal are sampled at a second detection cycle longer than the first detection cycle, and 2 representing the absolute position within one rotation of the motor rotation shaft. A backup arithmetic circuit that calculates a pole-side one-turn absolute position and a two-pole-side multi-rotation value that represents the number of rotations from the origin of the motor rotation shaft;
A power supply switching control circuit that operates the main arithmetic circuit and the backup arithmetic circuit with power supplied from a main power source and operates only the backup arithmetic circuit with power supplied from the backup power source when the main power source is shut off When,
When the main arithmetic circuit and the backup arithmetic circuit are operating with power supplied from the main power source, the multi-pole one-turn absolute value and the two-pole one-turn absolute value in the second detection cycle And an abnormality diagnosis circuit that determines that an abnormality has occurred when a state where the difference between these values is equal to or greater than a predetermined value continues for a predetermined number of times.

  According to this configuration, the rotational position of the motor rotation shaft can be detected continuously even when the main power supply is shut off. Also, during normal operation with power supplied from the main power supply, the rotational position of the motor rotation shaft calculated from the two-pole magnetic encoder is periodically calculated from the multi-pole magnetic encoder. By comparing with the position, erroneous detection due to a system error of the main arithmetic circuit can be monitored, so that a highly reliable detection operation can be realized.

Next, in the magnetic absolute encoder of the present invention,
The main arithmetic circuit samples the two-pole-side A-phase combined signal and the two-pole-side B-phase combined signal at the first detection cycle, and represents a second absolute position within one rotation of the motor rotation shaft. Calculate the absolute position of 1 pole on the 2 pole side,
The abnormality diagnosis circuit compares the multi-pole side one-turn absolute position with the second two-pole side one-turn absolute position, and a state in which a difference between these values is equal to or greater than a predetermined value continues for a predetermined number of times. In some cases, it is determined that an abnormality has occurred.

  According to this configuration, the amplifier in the main arithmetic circuit is periodically compared in the main arithmetic circuit with the rotational position calculated from the multipole magnetic encoder and the rotational position calculated from the two magnetic encoder. Since the erroneous detection based on the occurrence of an abnormality in the system, detection unit (detection element, magnet), etc. can be monitored at high speed, the reliability of the detection operation can be further improved.

  In the magnetic absolute encoder of the present invention, the influence of leakage magnetic flux of the electromagnetic brake built in the motor and the influence of leakage magnetic flux of the two sets of magnetic encoders in the magnetic absolute encoder can be removed from the detection signal. Detection accuracy can be increased.

  In addition, the rotational position calculated by the main arithmetic circuit based on the detection signal of the multi-pole magnetic encoder, the rotational position calculated by the main arithmetic circuit and the backup arithmetic circuit based on the detection signal of the two-pole magnetic encoder, Comparing. Therefore, the reliability of the detection operation can be increased.

FIGS. 1A and 1B are a schematic longitudinal sectional view and an end view showing a rear end surface of a motor with an electromagnetic brake in which a magnetic absolute encoder to which the present invention is applied are incorporated, respectively. It is a schematic block diagram mainly showing a control system of a magnetic absolute encoder. (A) is a front view which shows a board | substrate holding assembly and a flexible printed wiring board, (b) is the sectional drawing. It is an expanded view which shows the state which expand | deployed the flexible printed wiring board on the plane.

  Hereinafter, a motor with an electromagnetic brake incorporating a magnetic absolute encoder according to an embodiment of the present invention will be described with reference to the drawings.

[Motor with electromagnetic brake]
FIGS. 1A and 1B are a schematic longitudinal sectional view showing a motor incorporating a magnetic absolute encoder to which the present invention is applied and an end view showing a rear end face thereof, respectively. The motor 1 includes a cylindrical motor case assembly 2, and a front end portion of the motor case assembly 2 is a large-diameter mounting flange 3. A hollow motor rotating shaft 4 extending through the center of the motor case assembly 2 is disposed inside the motor case assembly 2. The motor rotating shaft 4 is supported by the motor case assembly 2 in a rotatable state via a front bearing 5 and a rear bearing 6 in front and rear portions in the direction of the motor rotation center axis 1a.

  A motor rotor 7 is attached to a portion of the motor rotating shaft 4 adjacent to the rear side of the front bearing 5, and the motor stator 8 is attached to the motor case assembly 2 side so as to surround the motor rotor 7 concentrically. It has been. An electromagnetic brake 9 is disposed on the rear side of the motor rotor 7 on the motor rotating shaft 4.

  The electromagnetic brake 9 is, for example, a non-excited operation type, and a braking force is applied to the motor rotating shaft 4 by a spring force (not shown) in a non-excited state, and the spring force is canceled by the electromagnetic force in an excited state. Thus, the braking force of the motor rotating shaft 4 is released. The electromagnetic brake 9 includes an electromagnet 12, and the electromagnet 12 includes an annular yoke 10 fixed to the motor case assembly 2 side, and an electromagnetic coil 11 disposed therein. A rear bearing 6 is mounted concentrically on the inner peripheral surface of the yoke 10, and a rear portion of the motor rotating shaft 4 is supported by the rear bearing 6 in a rotatable state.

  A magnetic absolute encoder 20 is disposed in a portion of the motor rotating shaft 4 adjacent to the rear side of the yoke 10. The rear end of the motor case assembly 2 is sealed with a disk-shaped encoder cover 17. The encoder cover 17 is formed with a central opening 17 a that communicates with the hollow portion 4 a of the motor rotation shaft 4. A motor connector 18 and an encoder connector 19 are attached to positions on the outer peripheral side of the encoder cover 17 at positions adjacent to each other in the circumferential direction.

[Magnetic absolute encoder]
FIG. 2 is a schematic block diagram showing mainly the control system of the magnetic absolute encoder 20. The detection unit of the magnetic absolute encoder 20 includes two sets of magnetic encoders, one of which is a multipolar magnetic encoder 21 and the other of which is a two-pole magnetic encoder 22.

  The multipole magnetic encoder 21 includes a multipole ring magnet 30 and a plurality of pairs of magnetic detection elements, in this example, two pairs of Hall elements 31 to 34. The multipolar ring magnet 30 has a circular outer peripheral surface magnetized so that S pairs of magnetic pole pairs (S: an integer of 2 or more) are formed at equal angular intervals along the circular outer peripheral surface. The Hall elements 31 (M1) and 33 (M2) obtain A-phase detection signals (multipolar A-phase signals), and the Hall elements 32 (M3) and 34 (M4) have a phase of 90 from the A phase. These arrangement positions are set so that B-phase detection signals (multipolar B-phase signals) of different degrees can be obtained, and in this example, they are arranged at an angular interval of approximately 90 degrees.

  The other two-pole magnetic encoder 22 includes a two-pole ring magnet 40 and a plurality of magnetic detection elements, in this example, two pairs of Hall elements 41 to 44. The two-pole ring magnet 40 has a circular outer peripheral surface that is two-pole magnetized to form a pair of magnetic poles. The Hall elements 41 to 44 are arranged at an angular interval of 90 degrees along the circular outer peripheral surface of the two-pole ring magnet 40, and an A-phase detection signal (dipole-side A-phase signal) is transmitted from the Hall element 41 (T1). ) And a B-phase signal (bipolar B-phase signal) having a phase difference of 90 degrees is obtained from the Hall element 42 (T2). In addition, an A-phase detection signal (bipolar A (−) phase signal) is obtained from the Hall element 43 (T3), and a B-phase detection signal (T4) is detected from the Hall element 44 (T4). Bipolar side B (-) phase signal) is obtained.

  The detection signals from the Hall elements 31 to 34 and 41 to 44 are synthesized via a connection portion (signal synthesis circuit) mounted on the IF wiring board 23 to obtain a multipolar A-phase composite signal MA and a multipolar side. A B-phase composite signal MB, a two-pole A-phase composite signal TA, and a two-pole B-phase composite signal TB are generated. These signals are supplied to an arithmetic circuit for signal processing, which will be described later, and the arithmetic circuit calculates the absolute rotational position within one rotation of the motor rotating shaft 4 and the rotational speed from the origin position of the motor rotating shaft 4. The

  Here, since the electromagnetic brake 9 is disposed adjacent to the detection unit of the magnetic absolute encoder 20, the detection signals of the magnetic encoders 21 and 22 on the multi-pole side and the 2-pole side are caused by the leakage magnetic flux of the electromagnetic brake 9. A noise component is included, resulting in a decrease in detection accuracy. Further, in the magnetic encoder 21 on the multipole side, the detection accuracy is reduced by a noise component due to leakage magnetic flux from the adjacent magnetic encoder 22 on the two pole side.

  In this example, in the magnetic encoder 22 on the two-pole side, the A-phase signal obtained from the Hall element 41 and the two-pole A (-) phase signal that is the opposite phase signal of the A phase obtained from the Hall element 43 are added. Thus, the noise component due to the leakage magnetic flux from the electromagnetic brake 9 included in these signals is removed, and the two-pole A-phase composite signal TA is generated. Similarly, by adding the two-pole side B-phase signal and the two-pole side B (−) phase signal obtained from the Hall elements 42 and 44, noise due to leakage magnetic flux from the electromagnetic brake included in these signals is added. The components are removed to generate a bipolar side B-phase composite signal TB.

  Further, in the magnetic encoder 21 on the multipole side, by adding the in-phase multipole A phase signals obtained from the Hall elements 31 and 32, the leakage magnetic flux from the two-pole magnet contained in these signals is added. The noise component is removed. Further, by connecting the signal lines from which the pair of multipolar A-phase signals are obtained in reverse phase, noise components due to leakage magnetic flux from the electromagnetic brake 9 included in these signals are removed. Similarly, by adding the in-phase multipolar B-phase signals obtained from the Hall elements 33 and 34, noise components due to leakage magnetic flux from the dipole magnets included in these signals are removed, and these multiple components are removed. By connecting the signal lines from which the pole-side B-phase signal is obtained in reverse phase, noise components due to leakage magnetic flux from the electromagnetic brake 9 included in these signals are removed. As a result, a multi-pole side A-phase composite signal MA and a multi-pole side B-phase composite signal MB from which noise components due to leakage magnetic flux have been removed are obtained. Therefore, the detection accuracy of the magnetic absolute encoder 20 can be increased by using these signals.

  Next, the magnetic absolute encoder 20 rotates the motor based on the multipolar A-phase composite signal MA, the multipolar B-phase composite signal MB, the 2-pole A-phase composite signal TA, and the 2-pole B-phase composite signal TB. A main operation circuit 70 is provided for calculating the absolute value θ1 of one rotation of the shaft 4, the multi-rotation value N, and the speed. Also, based on the 2-pole A-phase composite signal TA and 2-pole B-phase composite signal TB, the 2-pole-side 1-turn absolute value θ (2), which is the absolute value of 1-turn of the motor rotating shaft 4, A backup operation circuit 80 for calculating a certain two-pole multi-rotation value N (2) and speed is provided.

  Here, the multipolar side A-phase combined signal MA and the multipolar side B-phase combined signal MB are amplified via the amplifier circuit 71a. The amplified detection signals A1 and B1 are converted into digital signals by the AD converter 72a, and the obtained digital signals are supplied to the signal processing unit 73 of the main arithmetic circuit 70. The two-pole A-phase combined signal TA and the two-pole B-phase combined signal TB are amplified via the amplifier circuits 71c and 71d, and the amplified detection signals A3 and B3 are converted into digital signals via the AD converter 72b. After the conversion, the signal processing unit 73 is supplied.

  In the signal processing unit 73, an angle calculation is performed using the signals A1 and B1 to calculate a multipolar angle θ (MP), an angle calculation is performed using the signals A3 and B3, and a two-pole one-turn absolute value θ ( 2P). Based on the calculated value θ (2P) and the magnetic pole position correction information stored and held in the memory 73a, the multipolar angle θ (MP) is corrected to obtain the one-rotation absolute value θ1. This correction method can be performed based on the absolute rotational position detection method disclosed in Patent Document 2.

  Further, the signal processing unit 73 calculates the multi-rotation value N and the speed based on the one-rotation absolute value θ1. The calculated position data (θ1, N, speed) is converted into data for serial transfer by the data converter 74 and then transferred from the transmission / reception interface 75 to a host system (not shown). In the host system, the rotational position of the motor rotating shaft 4 can be recognized in an absolute format based on such information.

  Next, the two-pole A-phase combined signal TA and the two-pole B-phase combined signal TB are amplified via the amplifier 81a and supplied as amplified detection signals A2 and B2 to the backup arithmetic circuit 80. In the backup arithmetic circuit 80, these signals A2 and B2 are digitized via the AD converter 82, the angle calculation is performed using the digitized detection signal, and the two-pole one-turn absolute value θ2 and the two-pole multi-rotation value are obtained. N (2) and speed are calculated.

Here, the 1-rotation absolute value θ1, the 2-pole-side 1-rotation absolute value θ (2P), and the 2-pole-side 1-rotation absolute value θ2 are absolute values within one rotation of the motor rotating shaft 4 obtained by angle calculation. The multi-rotation value N and the 2-pole multi-rotation value N (2) are rotation counts from a predetermined origin, which are obtained by angle calculation. The detection signals A1, B1, A2, and B2 are expressed as follows, and the multipolar angles θ (MP) and θ (2P) are calculated as follows by angle calculation, and based on this, the absolute rotation position θ1 is calculated. Is done. The two-pole side one-rotation absolute value θ2 is also calculated in the same manner as θ1.
A1 = Vasin (θ−α)
B1 = Vbcos (θ−α)
A2 = Vcsin (θ−β)
B2 = Vdcos (θ−β)
θ (MP) = tan ⁻¹ ((b / Vb) / (a / Va)) + α
θ (2P) = tan ⁻¹ ((d / Vd) / (c / Vc)) + β
When the main power is turned on, the absolute one-rotation position θ1 is calculated using the multipolar angle θ (MP), the value θ (2P), and the magnetic pole position correction information. Here, assuming that the magnetic pole position correction information (magnetic pole position) is Ps and the number of magnetic pole pairs is S, θ1 = θ (MP) + Ps (360 ° / S). Thereafter, θ1 is updated by adding θ (MP) to θ1.

  The main arithmetic circuit 70 performs arithmetic processing at high speed and high accuracy, and samples the detection signals A and B1 at a detection period of 11 μs, for example. The backup arithmetic circuit 80 performs arithmetic processing with lower power consumption than the main arithmetic circuit 70, and is slower and less accurate than the main arithmetic circuit 70. For example, the detection signals A2 and B2 are sampled at a detection period of 2.2 ms.

  Here, the magnetic absolute encoder 20 includes a power supply switching control circuit 90. In the normal operation, the power supply switching control circuit 90 supplies power supplied from the normal operation power supply (main power supply) 91 of the host system to both the main arithmetic circuit 70 and the backup arithmetic circuit 80 to operate them. . When the power supply from the normal operation power supply 91 is cut off, the power supply source is switched to the backup power supply 92, and the supply power from the backup power supply 92 is supplied only to the backup arithmetic circuit 80. Therefore, at the time of backup, only the backup arithmetic circuit 80 operates to calculate only the two-pole-side one-rotation absolute value θ2 and the two-pole-side multi-rotation value N (2).

  The main arithmetic circuit 70 is provided with an abnormality diagnosis circuit 100 for self-diagnosis of whether or not a detection error has occurred during normal operation. When it is determined that an abnormality has occurred, that fact is indicated. An alarm signal is sent to the host system.

  The abnormality diagnosis circuit 100 compares the multipolar one-turn absolute value θ1 calculated by the main arithmetic circuit 70 with the two-pole one-turn absolute value θ2 calculated by the backup arithmetic circuit 80 during normal operation. Then, when a difference between these values is equal to or greater than a predetermined difference, it is determined that an abnormality has occurred. In the abnormality diagnosis circuit 100, for example, both calculated values are compared at a period of 2.2 ms, and it is detected ten times continuously that there is an inconsistent state in which the difference between the two calculated values causes a control problem. If so, it is determined that an abnormality has occurred.

  Further, the abnormality diagnosis circuit 100 compares the multi-rotation value N calculated by the main arithmetic circuit 70 with the two-pole multi-rotation value N (2) calculated by the backup arithmetic circuit 80, and the difference between these values is It is determined that an abnormality has occurred when a state equal to or greater than a predetermined difference continues for a predetermined number of times (for example, 10). This abnormality detection process is always performed during normal operation after power is turned on.

  Further, the abnormality diagnosis circuit 100 compares the multipolar one-turn absolute value θ1 calculated by the main arithmetic circuit 70 with the two-pole one-turn absolute value θ (2P) also calculated by the main arithmetic circuit 70, It is determined that an abnormality has occurred when the difference between these values is equal to or greater than a predetermined difference for a predetermined number of times (for example, 10 times). This abnormality diagnosis is performed by comparing both calculated values at the same operating speed as the operating speed of the main arithmetic circuit 70, for example, at a cycle of 11 μs.

  The magnetic absolute encoder 20 has a multi-rotation value setting function. In the multi-rotation value setting function, when the power supply from the normal operation power supply is resumed and the normal operation state is restored from the backup state, the backup multi-rotation value N ( 2) is transferred to the main arithmetic circuit 70 and is set as the multi-rotation value N at that time. Since the main arithmetic circuit 70 does not operate at the time of backup, the multi-rotation value N disappears when the normal operation is restored from the backup. By setting the multi-rotation value N (2) when returning to the normal operation, the subsequent calculation operation of the multi-rotation value N can be resumed.

(Mechanical structure of the detector)
Next, the mechanical configuration of the detection unit of the magnetic absolute encoder 20 will be described in detail. First, as shown in FIG. 1, the mechanism of the magnetic absolute encoder 20 includes an annular boss 24 concentrically fixed to the outer peripheral surface of the rear end portion of the motor rotating shaft 4. A multipolar ring magnet 30 and a dipolar ring magnet 40 are fixed to the circular outer peripheral surface at positions adjacent to each other in a coaxial state.

  In addition, a substrate holding assembly 50 is disposed so as to surround these magnets 30 and 40. A flexible printed wiring board 60 having a constant width is held in a looped shape so as to surround the multi-pole ring magnet 30 and the dipole ring magnet 40 by the board holding assembly 50. The flexible printed wiring board 60 is mounted with Hall elements 31 to 34 on the multi-pole side and Hall elements 41 to 44 on the two-pole side. In addition, a wiring pattern drawn from each Hall element is printed. On the outside of the substrate holding assembly 50, an arc-shaped IF wiring board 23 having a predetermined width extending at a predetermined angle is disposed.

  3A is a front view showing the board holding assembly 50 and the flexible printed wiring board 60, and FIG. 3B is a cross-sectional view thereof. As shown in these drawings, the substrate holding assembly 50 includes an annular base plate 55 having a constant width and four first to fourth identical shapes fixed to one annular end surface 56 of the base plate 55. Board mounting bases 51-54. The base plate 55 is formed with a plurality of bolt holes along the circumferential direction, and is fixed to the yoke 10 with fastening bolts.

  The board mounting bases 51 to 54 are formed of a rectangular metal plate having a constant thickness, and are vertically attached to the annular end surface 52 of the base plate 51 at an angular interval of 90 degrees along the circumferential direction. Yes. In each of the board mounting bases 51 to 54, the inner planes facing the center side of the base plate 55 are board mounting surfaces 51a to 54a, to which the flexible printed wiring board 60 bent in a loop shape is fixed.

  Each of the board mounting bases 51 to 54 can be screwed in a state of being slightly movable in the tangential direction of a circle 57 inscribed in the board mounting surfaces 51a to 54a, and finally the annular end face 56 by an adhesive. It is fixed to.

  Here, as can be seen from FIG. 1, in this example, the base plate 55 of the substrate holding assembly 50 has an end surface portion of the inner peripheral edge thereof in contact with the end surface of the outer ring 6 a of the rear bearing 6. It is functioning. The end surface on the opposite side of the outer ring 6 a is in contact with the inner peripheral side end surface of the yoke 10. The inner ring 6 b of the rear bearing 6 is held between the end surface of the boss 24 and a step surface formed on the motor rotating shaft 4. As described above, since the base plate 55 and the boss 24 also serve as bearing holders, the number of parts can be reduced, which is advantageous for downsizing, compactness, and cost reduction.

  Next, FIG. 4 is a development view showing the flexible printed wiring board 60 held by the board holding assembly 50 in a state where the flexible printed wiring board 60 is developed on a plane. The flexible printed wiring board 60 as a whole has a constant width in a slanting direction from an elongated linear substrate body portion 65 having a constant width and one side edge portion of a middle portion in the length direction of the substrate body portion 65. The leading portion of the leading portion 66 serves as a terminal portion 67 for connection to the IF wiring board 23 side. Further, the side edge portion of the substrate body portion 65 to which the root portion of the lead portion 66 is connected is a reinforcing portion in which a reinforcing layer 68 having a constant width and a length including the root portion is formed.

  The substrate main body portion 65 is formed with rectangular first to fourth element mounting portions 61 to 64 at two portions of the both ends and substantially the same distance between the two ends. A rectangular reinforcing plate 69 is laminated on the back surface of the fourth element mounting portions 61 to 64. The reinforcing plate 69 defines adhesive surfaces that are bonded and fixed to the substrate mounting surfaces 51a to 54a of the substrate mounting bases 51 to 54, and ensures the flatness of the element mounting portions 61 to 64. A wiring pattern composed of a large number of wirings is printed on the substrate main body portion 65 and the lead-out portion 66.

  On the first element mounting portion 61, the multi-pole-side hall element 31 (M1) and the dipole-side hall element 41 (T1) are mounted at intervals in the width direction. A multi-pole Hall element 32 (M3) and a dipole Hall element 42 (T2) are mounted on the surface of the second element mounting portion 62, and the third element mounting portion 63 has a multi-pole side. Hall element 33 (M2) and the two-pole Hall element 43 (T3) are mounted. The fourth element mounting portion 64 includes a multi-pole Hall element 34 (M4) and a two-pole Hall element. 44 (T4) is mounted. The first to fourth element mounting portions 61 to 64 are respectively fixed to the first to fourth substrate mounting surfaces 51 a to 54 a in the substrate holding assembly 50 with screws and an adhesive.

  As can be seen from FIG. 3, the flexible printed wiring board 60 having this configuration is bent in a loop shape so that its surface faces inward, and is fixed to the board mounting surfaces 51a to 54a. In addition, the portion between the substrate mounting surfaces 51a and 52a, the portion between the substrate mounting surfaces 52a and 53a, and the portion between the substrate mounting surfaces 53a and 54a are in a state of swelling outward (slack state). It is laid over. Note that the flexible printed wiring board 60 is arranged so as to fit within a portion within the outer diameter of the base plate 55 so as not to interfere with the outer peripheral portion.

  In the positioning operation of the Hall element, the flexible printed wiring board 60 is fixed to the board holding assembly 50 and mounted so as to face the multipolar and bipolar ring magnets 30 and 40 attached to the motor rotating shaft 4. Further, the lead-out portion 66 of the flexible printed wiring board 60 is bent at a substantially right angle with the root portion as the center, and the terminal portion 67 at the tip is connected to the connector portion of the IF wiring board 23 located on the outer peripheral side. .

  In this state, these positions are adjusted based on the detection signals of the first to fourth Hall elements 31 to 34 on the multipolar side. That is, an appropriate detection signal is obtained while moving each of the board mounting bases 51 to 54.

  Here, in the 1st-4th element mounting parts 61-64 of the flexible printed wiring board 60, it mounts so that a multipolar Hall element and a 2 pole side Hall element may become predetermined | prescribed positional relationship. Therefore, if the multi-pole ring magnet 30 and the 2-pole ring magnet 40 are assembled to the motor rotating shaft 4 with high accuracy, the multi-pole hall elements 31 to 34 are positioned to perform the 2-pole hall. The positioning of the elements 41 to 44 is performed simultaneously. Therefore, the positioning operation of the Hall element is simplified. After positioning, each of the board mounting bases 51 to 54 is fixed to the adjustment position with an adhesive.

  In addition, since the Hall elements are mounted on the flexible printed circuit board 60 and the wiring pattern from each Hall element is printed, a plurality of lead wires are connected to the printed circuit board on which each Hall element is mounted. The wiring work for drawing these lead wires to the IF wiring board 23 is not necessary.

  Further, since the board holding assembly 50 holding the flexible printed wiring board 60 can be easily removed, maintenance and inspection work is simplified. The replacement operation of the flexible printed wiring board 60 on which the Hall element is mounted can be easily performed with the board holding assembly 50 removed.

  Further, since the lead-out portion 66 of the flexible printed circuit board 60 is easily bent in the out-of-plane direction, the operation of bending this portion and connecting it to the IF circuit board 23 located outside in the radial direction can be easily performed. Can do. Further, a reinforcing layer 68 having a constant width is formed on the side edge portion of the substrate body portion 65 to which the base portion of the lead portion 66 is connected. Therefore, even if an excessive force is applied to the side edge portion due to the bending of the drawer portion 66, the portion is not damaged, so that it is possible to prevent the occurrence of problems such as disconnection.

DESCRIPTION OF SYMBOLS 1 Motor 1a Rotation center axis 2 Motor case assembly 3 Mounting flange 4 Motor rotation shaft 4a Hollow part 5 Front side bearing 6 Rear side bearing 7 Motor rotor 8 Motor stator 9 Electromagnetic brake 10 Yoke 11 Electromagnetic coil 12 Electromagnet 17 Encoder cover 17a Center opening 18 Motor Connector 19 Encoder Connector 20 Magnetic Absolute Encoder 21 Multipole Magnetic Encoder 22 2-pole Magnetic Encoder 23 IF Wiring Board 30 Multipole Ring Magnets 31-34 Multipole Hall Element 40 2-pole Ring Magnets 41-44 2 Hall element 50 on the pole side Substrate holding assemblies 51-54 Substrate mounting bases 51a-54a Substrate mounting surface 55 Base plate 56 Annular end surface 60 Flexible printed circuit boards 61-64 Element mounting portion 65 Substrate Main body portion 66 Pull-out portion 67 Terminal portion 68 Reinforcing layer 69 Reinforcing plate 70 Main arithmetic circuits 71a, 71b, 71c, 71d, 81a, 81b Amplifying circuits 72a, 72b, 82 AD converter 73 Signal processing unit 73a Memory 74 Data conversion unit 75 Transmission / reception Interface 80 Backup arithmetic circuit 90 Power supply switching control circuit 91 Normal operation power supply 92 Backup power supply 100 Abnormality diagnosis circuit

Claims (4)

A magnetic absolute encoder that is arranged adjacent to an electromagnetic brake for restraining rotation of a motor rotation shaft and is used for detecting a rotation position of the motor rotation shaft,
A two-pole magnet fixed coaxially to the motor rotating shaft and having a pair of magnetic pole pairs formed on a circular outer peripheral surface;
Along with the rotation of the two-pole magnet, one pole-side A-phase signal, two-pole-side B-phase signal, and two-pole-side A (−) phase that is an inverted signal of the two-pole-side A-phase signal per rotation. Four bipolar-side magnetic sensing elements arranged to obtain a signal and a two-pole B (-) phase signal that is an inverted signal of the two-pole B-phase signal;
A multipolar magnet fixed coaxially at a position adjacent to the two-pole magnet on the motor rotation shaft and having S pairs of magnetic pole pairs (S: an integer of 2 or more) formed on a circular outer peripheral surface;
At least four multipole-side magnetic detection elements arranged to obtain a pair of multipole-side A-phase signals and a pair of multi-pole-side B-phase signals with an S period per rotation in accordance with the rotation of the multipole magnet;
A multipole-side signal synthesis circuit that synthesizes the signals obtained from the multipole-side magnetic detection element to generate a multipole-side A-phase synthesized signal and a multi-pole-side B-phase synthesized signal;
A two-pole-side signal combining circuit that combines the signals obtained from the two-pole-side magnetic detection element to generate a two-pole-side A-phase combined signal and a two-pole-side B-phase combined signal;
The two-pole-side signal synthesis circuit adds the two-pole-side A-phase signal and the two-pole-side A (−)-phase signal, thereby causing noise due to leakage magnetic flux from the electromagnetic brake included in these signals. By removing the component and adding the two-pole side B-phase signal and the two-pole side B (−) phase signal, the noise component caused by the leakage magnetic flux from the electromagnetic brake contained in these signals is removed. ,
The multipole-side signal synthesis circuit adds the pair of multipole-side A-phase signals to remove noise components due to leakage magnetic flux from the two-pole magnets included in these signals, and By adding the other inverted signal to one of the multipolar A phase signals, the noise component due to leakage magnetic flux from the electromagnetic brake contained in these signals is removed, and the pair of multipolar B phases By adding the signals, the noise component due to the leakage magnetic flux from the two-pole magnet contained in these signals is removed, and the other inverted signal is added to one of the pair of multipolar B-phase signals. Thus, a noise absolute encoder included in these signals due to leakage magnetic flux from the electromagnetic brake is removed. In claim 1,
Sampling the multi-pole side A-phase composite signal and the multi-pole side B-phase composite signal in a first detection period, and a multi-pole side one-turn absolute value representing an absolute position within one turn of the motor rotation shaft, and A main arithmetic circuit that calculates a multi-pole multi-rotation value representing the number of rotations from a predetermined origin of the motor rotation shaft;
The two-pole side A-phase composite signal and the two-pole side B-phase composite signal are sampled at a second detection cycle longer than the first detection cycle, and 2 representing the absolute position within one rotation of the motor rotation shaft. A backup arithmetic circuit that calculates a pole-side one-turn absolute position and a two-pole-side multi-rotation value that represents the number of rotations from the origin of the motor rotation shaft;
A power supply switching control circuit that operates the main arithmetic circuit and the backup arithmetic circuit with power supplied from a main power source and operates only the backup arithmetic circuit with power supplied from the backup power source when the main power source is shut off And a magnetic absolute encoder. In claim 2,
When the main arithmetic circuit and the backup arithmetic circuit are operating with power supplied from the main power source, the multi-pole one-turn absolute value and the two-pole one-turn absolute value in the second detection cycle A magnetic absolute characterized by having an abnormality diagnosis circuit that determines that an abnormality has occurred when a difference between these values exceeds a predetermined value for a predetermined number of times. encoder. In claim 3,
The main arithmetic circuit samples the two-pole-side A-phase combined signal and the two-pole-side B-phase combined signal at the first detection cycle, and represents a second absolute position within one rotation of the motor rotation shaft. Calculate the absolute position of 1 pole on the 2 pole side,
The abnormality diagnosis circuit compares the multi-pole side one-turn absolute position with the second two-pole side one-turn absolute position, and a state in which a difference between these values is equal to or greater than a predetermined value continues for a predetermined number of times. A magnetic absolute encoder characterized by determining that an abnormality has occurred.

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