JP2008271765A - Brake for holding motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake for holding motor which is specialized in the function of holding a rotating shaft, with a wire connection circuit being simplified for smaller size and lower cost, while cogging force is eliminated at releasing of brake, without affecting the characteristics during motor operation. <P>SOLUTION: The motor holding brake comprises a rotor core 3 in which a plurality of rotor-side salient poles 4 are protruded circumferentially on the outer peripheral wall at a constant angular pitch, being bonded coaxially to a motor rotating shaft; a stator core 6 in which a plurality of stator-side salient poles 7 are protruded circumferentially on the inner peripheral wall at a constant angular pitch, arranged to enclose the rotor core 3, with a specified gap against the rotor core 3; and a cylindrical coil 8 wound on the stator core 6. By energizing the cylindrical coil 8 with a DC current from a DC power supply 9, a torque pulsation corresponding to the rotational position of the rotor core 3 is generated. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motor holding brake that holds the rotational position of a rotor of a motor body when the motor is stopped.

  In a conventional motor, an electromagnetic brake is attached to the rotor and braking is applied to the rotor. However, the magnetic circuit of the electromagnetic brake is larger than the magnetic circuit of the motor, resulting in an increase in the size of the device and a problem that there are wear parts and maintenance is troublesome.

  In view of such a situation, various compact brake mechanisms for applying a holding brake to the rotor without contact have been proposed. For example, in the one described in Patent Document 1, when it is determined that the motor is stopped, a direct current excitation current is caused to flow through a three-phase coil of the motor body to generate a magnetic attractive force, and this magnetic attractive force attracts the rotor magnet. The rotor was kept rotating. Moreover, in the thing of patent document 2, a cogging torque suppression torque is generated, a motor is drive | operated, a drive power supply is stopped, and a rotor is made into the front-end | tip of a stator teeth part, and the permanent magnet of a rotor. It was held by the suction force in between and stopped.

JP-A-11-341590 JP-A-5-146185

In the conventional brake mechanism described in Patent Document 1, two types of connection for braking and rotation are required for the connection for energization to the three-phase coil of the motor body, and the connection circuit becomes complicated. was there.
In the conventional brake mechanism described in Patent Document 2, cogging torque remains as a braking force when the motor rotates. Therefore, if a torque larger than the amplitude of the cogging torque is not applied, it will return to the stable point and will not rotate as a motor, so at the time of starting, a large current must be passed over the cogging torque, resulting in a large loss. There was a problem.

  The present invention has been made to solve such a problem, specializing in the function of holding the rotating shaft, simplifying the connection circuit, realizing a small size and low cost, and at the time of releasing the brake. An object of the present invention is to obtain a motor holding brake that does not affect the characteristics during motor operation by eliminating the cogging force.

  The brake for holding a motor according to the present invention is manufactured in a thick cylindrical shape, and a plurality of rotor-side salient poles are provided on the outer peripheral wall surface at the first equiangular pitch in the circumferential direction, and are fixed coaxially to the rotating shaft. A rotor core and a cylindrically produced stator-side salient pole are projected on the inner peripheral wall surface at a second equiangular pitch in the circumferential direction, and have a certain gap with respect to the rotor core. A stator core disposed so as to surround the outer periphery of the rotor core, a stator coil wound around the stator core, and a first power supply means for supplying a direct current to the stator coil And by applying a direct current to the stator coil by the first power supply means, torque pulsation corresponding to the rotational position of the rotor core is generated.

  According to this invention, a DC current is passed through the stator coil separately from the motor, and a magnetic attraction force is generated between the rotor-side salient pole and the stator-side salient pole to hold the rotating shaft. Because it is configured to stop, there is no problem that the wiring circuit resulting from the combined use of the three-phase coil of the motor for driving and braking is complicated, and the motor holding brake with a simple configuration In addition, there is no brake wear and the instability of mechanical brakes using friction can be eliminated. Also, since the cogging force disappears by stopping energization of the stator coil, it is not necessary to increase the energizing current to the motor when starting the motor, and the loss increases due to the cogging force remaining as a braking force Is prevented.

Embodiment 1 FIG.
FIG. 1 is a diagram for explaining the configuration of a motor holding brake according to Embodiment 1 of the present invention, and FIG. 2 is a part of the configuration of a brake mechanism in the motor holding brake according to Embodiment 1 of the present invention. FIG. 3 is a cutaway perspective view, FIG. 3 is a cross-sectional view showing a stator iron core and a rotor iron core constituting the motor holding brake according to the first embodiment of the present invention, and FIG. 4 is a motor holding motor according to the first embodiment of the present invention. FIG. 5 is a waveform diagram showing torque pulsation in the motor holding brake according to Embodiment 1 of the present invention.

  1 to 3, the motor holding brake has a rotor core 3 fixed to the motor rotating shaft 2 and a constant gap g with respect to the rotor core 3. The brake mechanism unit 1 includes a stator 5 which is surrounded and fixed to a fixing member (not shown). The motor holding brake further includes a DC power supply 9 as a first power supply means for supplying a DC current to a cylindrical coil 8 of the stator 5 to be described later and generating a torque pulsation corresponding to the rotational position of the rotor core. .

  The rotor core 3 is made of a low-carbon steel such as S10C, for example, in a thick cylindrical shape by a cold forging method, and a plurality of rotor-side salient poles 4 project from the outer peripheral wall surface at a first equiangular pitch in the circumferential direction. Has been. Each rotor-side salient pole 4 is composed of first and second rotor-side salient poles 4a and 4b that are spaced apart from each other at a predetermined interval Lc in the axial direction. In the portion where the first and second rotor-side salient poles 4a and 4b are opposed to each other at a predetermined interval in the axial direction, the rotor core 3 has a U-shaped cross section. The motor rotating shaft 2 is press-fitted and fixed in a through hole 3 a formed at the axial center position of the rotor core 3.

  The stator 5 includes a stator core 6 and a cylindrical coil 8 as a stator coil wound around the stator core 6. The stator core 6 is made of a low carbon steel such as S10C in a cylindrical shape by a cold forging method, and a plurality of stator side salient poles 7 are provided on the outer peripheral wall surface in the circumferential direction at a second equiangular pitch. Yes. Each stator-side salient pole 7 includes first and second stator-side salient poles 7a and 7b that are spaced apart from each other at a predetermined interval Lc in the axial direction. In the portion where the first and second stator side salient poles 7a and 7b are opposed to each other at a predetermined interval in the axial direction, the stator core 6 has a U-shaped cross section. The cylindrical coil 8 is produced by winding a conductor wire in a cylindrical shape a predetermined number of times, and is formed on the stator core 6 so as to be positioned between the first and second stator side salient poles 7a and 7b facing in the axial direction. It is arranged. The first equiangular pitch and the second equiangular pitch are equal.

  Here, as shown in FIG. 4, the stator core 6 is composed of first and second cores 6A and 6B that are divided into two in the axial direction. Then, the first and second iron cores 6A, 6B are abutted so as to sandwich the cylindrical coil 8 from both sides in the axial direction, the abutting portions of the first and second iron cores 6A, 6B are joined, and the cylindrical coil 8 is The first and second stator-side salient poles 7a and 7b facing each other are assembled so as to be positioned between the pair.

Next, the operation of the thus configured motor holding brake will be described.
When a direct current is passed from the direct current power source 9 to the cylindrical coil 8, a magnetic flux A is generated so as to circulate around the cylindrical coil 8 as indicated by an arrow in FIG. 1. That is, the magnetic flux A enters the first rotor-side salient pole 4a from the first stator-side salient pole 7a, flows in the rotor core 3 to the second rotor-side salient pole 4b, and the second stator-side salient pole. 7b, and flows so as to flow through the stator core 6 to the first stator-side salient pole 7a. A magnetic attractive force acts between the rotor-side salient pole 4 and the stator-side salient pole 7, the rotor iron core 3 rotates, and the rotor-side salient pole 4 faces the stator-side salient pole 7. Stop in position. That is, the position where the rotor side salient pole 4 and the stator side salient pole 7 are opposed to each other in the radial direction is a stable point. As described above, cogging torque is generated to move the rotor-side salient pole 4 to a stable point in accordance with the relative position between the rotor-side salient pole 4 and the stator-side salient pole 7. When the rotor-side salient pole 4 and the stator-side salient pole 7 face each other in the radial direction, the cogging torque becomes zero, and the rotor-side salient pole 4 and the stator-side salient pole 7 are shifted in the circumferential direction. Cogging torque increases. Therefore, torque pulsation is generated between the rotor core 3 and the stator core 6 according to the relative position of the rotor-side salient pole 4 and the stator-side salient pole 7 as shown in FIG. .

This motor holding brake is attached to a motor (not shown) with the brake mechanism 1 mounted on the motor rotating shaft 2. When the motor stop signal is received, a direct current is supplied from the direct current power source 9 to the cylindrical coil 8, and the motor rotating shaft 2 is caused by the magnetic attractive force between the rotor side salient pole 4 and the stator side salient pole 7. Hold and stop. Thereby, even when a disturbance occurs when the motor is in a no-load state, the motor is held at a predetermined position.
When the motor operation signal is received, the energization to the cylindrical coil 8 by the DC power supply 9 is stopped, the magnetic attractive force between the rotor side salient pole 4 and the stator side salient pole 7 is lost, and the motor rotating shaft 2. That is, the motor is operated smoothly.

  As described above, according to the first embodiment, the motor holding brake is separate from the motor, and further, a DC current is passed through the cylindrical coil 8 so that the rotor side salient pole 4 and the stator side salient pole 7 are supplied. Since the magnetic rotating force is generated between the motor rotating shaft 2 and the motor rotating shaft 2 is held and stopped, the wiring circuit resulting from the combined use of the motor three-phase coil for driving and braking The motor holding brake can be realized with a simple configuration, the brake is not worn, and the instability of the mechanical brake using friction can be eliminated.

Moreover, since the magnitude of the braking force can be adjusted by controlling the magnitude of the energizing current to the cylindrical coil 8, the braking force can be repeatedly reproduced with the same value regardless of the temperature simply by controlling the energizing current to be constant. In addition, a stable braking force can be easily applied without any change in the braking force over time.
Further, since the cogging force disappears when the energization to the cylindrical coil 8 is stopped, it is not necessary to increase the energizing current to the motor when starting the motor, and the loss due to the cogging force remaining as a braking force is increased. Is prevented.

  The motor holding brake has an upper limit of the braking force, and when a force exceeding the upper limit of the braking force is applied, the motor rotating shaft 2 rotates out of step. Therefore, in applications where the motor is driven by a mechanical element such as a ball screw via a speed reducer, an impact force exceeding the upper limit of the braking force is applied to the motor from the load side during the holding operation of the motor rotating shaft 2. Since the motor rotating shaft 2 rotates out of step, it is possible to prevent a problem that the speed reducer or the like fails due to excessive impact force.

  In this motor holding brake, since the cylindrical coil 8 is arranged, the rotor-side salient pole 4 and the stator-side salient pole 7 between the stator core 6 and the rotor core 3 are parallel to the cylindrical coil 8. Since it becomes a magnetic circuit, the magnetomotive force required for the stator coil does not increase. Therefore, even if the number of salient poles is increased in order to increase the braking force (cogging force), an increase in coil loss is suppressed. Further, it is only necessary to provide a single cylindrical coil 8 having a simple shape, and mass productivity is improved. As described above, by using the cylindrical coil 8, a motor holding brake having a large braking force can be realized at low cost.

Since the number of poles of the motor is usually about 4 to 10 poles, when a cogging force is generated in the motor itself and the motor rotating shaft 2 is held by the motor alone, the energizing current is increased to obtain a large braking force. There is a need to.
This motor holding brake specializes in the function of holding the motor rotating shaft 2 and is designed with the number of salient poles increased to about several tens to 100, so that the motor alone can hold the motor rotating shaft 2. The energization current for obtaining the same braking force can be greatly reduced. Therefore, if this motor holding brake is used, system loss during holding can be reduced as compared with the case where the motor rotating shaft 2 is held by the motor alone.

  The frequency of the cogging force is the least common multiple of the number of magnetic poles of the stator core and the rotor core per one rotation of the rotor core. Therefore, in the motor holding brake designed to have the number of salient poles of about several tens to 100, the motor rotating shaft 2 is compared with the case where the motor rotating shaft 2 is normally held by the motor alone having the number of poles of about 4 to 10 poles. The rotational position can be maintained with high resolution.

  Here, when the number of salient poles is P, the waveform of the cogging torque can be expressed by Expression (1).

Τ ₁ is the cogging torque amplitude [Nm], θ is the rotational position [rad], and the salient pole number P is the least common multiple of the stator side salient pole number and the rotor side salient pole number.

  Here, this motor holding brake can be expressed as a magnetic spring when there is a torque fluctuation in the disturbance. Therefore, when the magnetic spring constant is set to k, k [Nm / rad] is obtained by differentiating equation (1) by θ. Is required. Therefore, the magnetic spring constant k is expressed by the formula (2).

  At the stable point of the cogging torque, θ = 0, so that the spring constant k can be approximated by Equation (3).

  Further, the relationship between the torque τ and the moment of inertia J is expressed by Expression (4).

  Note that ω is an angular frequency [rad / s].

Therefore, k = Jω ² can be calculated from the equations (3) and (4), and the resonance frequency f ₁ of the motor holding brake from k = Jω ² is expressed by equation (5).

  Here, when the motor holding brake is turned ON / OFF (the cylindrical coil 8 is energized / de-energized), the fluctuation load τ ′ [Nm] having the excitation frequency shown in the equation (6) is given as a disturbance. FIG. 6 shows the frequency characteristics of the vibration angle.

Note that F is the disturbance amplitude.
In FIG. 6, the holdable range of the motor holding brake is a range of θ ₁ = 2π / P [rad] or less. In other words, the motor holding brake cannot be held when the vibration angle becomes larger than θ ₁ = 2π / P [rad].
When the motor holding brake is OFF, the vibration angle θ with respect to the disturbance τ ′ is expressed by Equation (7).

From Expressions (4) and (7), the frequency f _{0 at which} the vibration angle is θ ₁ = 2π / P [rad] is expressed by Expression (8).

  The vibration angle θ is an angle within a range in which the rotor can swing around a stable point with respect to a disturbance having a certain frequency component.

From this, by setting the resonance frequency f ₁ to be greater than f ₀ or f _0, even when the disturbance frequency is equal to the resonance frequency f ₁ , the vibration amount of the motor holding brake is reduced as shown in FIG. It can be suppressed to a holdable range. That is, the number of salient poles P, the moment of inertia J, and the amplitude τ _{1 of the} cogging torque may be set so as to satisfy f ₁ ≧ f ₀ .
The same applies when the disturbance includes a harmonic component in addition to the DC component.

In the first embodiment, the stator core 6 and the rotor core 3 are made of a lump of low carbon steel such as S10C. However, the stator core 6 and the rotor core 3 are, for example, A predetermined number of thin sheets of low carbon steel may be laminated and integrated.
In the first embodiment, the motor is directly attached to the motor rotating shaft 2, but may be attached to a rotating shaft connected to the motor rotating shaft 2 via a power transmission mechanism.

  In the first embodiment, the preferred embodiment is described in which the rotor-side salient poles 4 and the stator-side salient poles 7 are formed at the same equiangular pitch to have the same number of salient poles. The number of salient poles of the rotor side salient pole 4 and the stator side salient pole 7 may be made different by changing the installation pitch. Moreover, it is preferable that the number of salient poles be several times the number of poles of the motor. In any case, the frequency of the cogging force is the least common multiple of the number of salient poles on the stator side and the number of salient poles on the rotor side per rotation of the rotor core. That is, the stable point of the cogging force is the least common multiple of the number of salient poles on the stator side and the number of salient poles on the rotor side per rotation of the rotor core. Therefore, when the number of salient poles on the stator side is equal to the number of salient poles on the rotor side, the amplitude of the cogging force is larger than when the number of salient poles on the stator side is different from the number of salient poles on the rotor side. can do.

Embodiment 2. FIG.
FIG. 7 is a sectional view showing a brake mechanism portion in a motor holding brake according to Embodiment 2 of the present invention.
In FIG. 7, the cylindrical coil 8 is produced by winding a conductor wire around a cylindrical winding fixing member 10 a predetermined number of times. Then, in a state where the cylindrical coil 8 is wound around the winding fixing member 10, it is disposed on the stator core 6 so as to be positioned between the first and second stator side salient poles 7 a and 7 b facing in the axial direction. Has been. The material of the cylindrical winding fixing member 10 may be a non-magnetic material, and a resin material, a metal material such as stainless steel or aluminum can be used. Other configurations are the same as those in the first embodiment.

  According to the second embodiment, since the cylindrical coil 8 is wound around the winding fixing member 10 and disposed on the stator core 6, the cylindrical coil 8 is displaced and interferes with the rotor core 3. Can be surely prevented.

Embodiment 3 FIG.
FIG. 8 is a sectional view showing a brake mechanism portion in a motor holding brake according to Embodiment 3 of the present invention.
In FIG. 8, the stator core 11 is made of a low carbon steel such as S10C in a cylindrical shape by a cold forging method, and the stator side salient poles 12 are arranged on the inner peripheral wall surface at a second equiangular pitch in the circumferential direction. Multiple protrusions are provided. Each stator-side salient pole 12 includes first and second stator-side salient poles 12a and 12b that are spaced apart from each other at a predetermined interval Lc ′ in the axial direction. Each of the first and second stator side salient poles 12a and 12b has a flange 13 extending in the axial direction from the inner peripheral end. In the portion where the first and second stator side salient poles 12a and 12b are opposed to each other at a predetermined interval in the axial direction, the stator core 11 has a C-shaped cross section. The cylindrical coil 8 is disposed in the stator core 11 so as to be accommodated in a space having a C-shaped cross section between the first and second stator-side salient poles 12a and 12b opposed in the axial direction.

  The rotor core 14 is made of a low-carbon steel such as S10C by a cold forging method and is formed into a thick cylindrical shape, and a plurality of rotor-side salient poles 15 project from the outer peripheral wall surface at a first equiangular pitch in the circumferential direction. Has been. Each rotor-side salient pole 15 includes first and second rotor-side salient poles 15a and 15b that are spaced apart from each other at a predetermined interval Lc 'in the axial direction. In the portion where the first and second rotor-side salient poles 15a and 15b are opposed to each other at a predetermined interval in the axial direction, the rotor core 14 has a U-shaped cross section. The motor rotation shaft 2 is press-fitted and fixed in a through hole 14 a formed at the axial center position of the rotor core 14. Here, the first equiangular pitch and the second equiangular pitch are equal. Other configurations are the same as those in the first embodiment.

  According to the third embodiment, the cylindrical coil 8 is arranged in the stator core 11 so as to be accommodated in a space having a C-shaped cross section between the first and second stator side salient poles 12a and 12b opposed in the axial direction. Therefore, the cylindrical coil 8 can be reliably prevented from being displaced and interfering with the rotor core 14 without using the winding fixing member 10.

Here, the torque pulsation when the same current is passed through the cylindrical coil 8 of the motor holding brake according to the first and third embodiments is measured, and the result is shown in FIG. In FIG. 9, the solid line indicates the third embodiment, and the dotted line indicates the first embodiment.
As can be seen from FIG. 9, the motor holding brake according to the third embodiment can obtain a torque pulsation having a larger amplitude than the motor holding brake according to the first embodiment.
This is because the opposing area between the stator-side salient pole 12 and the rotor-side salient pole 15 is increased by the provision of the flange 13 on the first and second stator-side salient poles 12a, 12b. caused by. Therefore, in Embodiment 3, in order to obtain torque pulsation equivalent to the motor holding brake in Embodiment 1, the axial length of stator core 11 can be shortened. That is, the motor holding brake can be reduced in size.

In the third embodiment, since the axial length Lc ′ between the flanges 13 of the first and second stator side salient poles 12a, 12b facing each other in the axial direction is shortened, Close leakage magnetic flux C is likely to occur. Therefore, in order to reduce the leakage magnetic flux C, the axial distance Lc ′ between the first and second stator side salient poles 12a and 12b facing each other in the axial direction is set between the stator core 11 and the rotor core 14. It is desirable to make it sufficiently large with respect to the gap g, and Lc ′ is preferably 10 times or more of g.
Also in the third embodiment, the cylindrical coil 8 can be easily mounted by dividing the stator core 11 into two in the axial direction.

Embodiment 4 FIG.
FIG. 10 is a schematic diagram illustrating a motor holding brake according to Embodiment 4 of the present invention.
In FIG. 10, the stator core 16 is made of a low carbon steel such as S10C in a cylindrical shape by a cold forging method, and the stator side salient poles 17 are arranged on the inner peripheral wall surface at a second equiangular pitch in the circumferential direction. Multiple protrusions are provided. The coil 18 as a stator coil is a concentrated winding coil wound around the stator core 16 by winding a conductor wire successively around each of the stator side salient poles 17 for a predetermined number of times. The rotor core 19 is made of a low-carbon steel such as S10C, for example, by a cold forging method and is formed into a thick cylindrical shape, and the rotor-side salient poles 20 project from the outer peripheral wall surface at a first equiangular pitch in the circumferential direction. ing. The motor rotating shaft 2 is press-fitted and fixed in a through hole 19 a formed in the axial center position of the rotor iron core 19. Here, the first equiangular pitch and the second equiangular pitch are equal.

  In the motor holding brake having the brake mechanism portion 1A configured as described above, when a direct current is passed from the direct current power source 9 to the coil 18, the stator side salient pole 17 passes through the core back portion of the stator core 16. It flows to the stator side salient pole 17 adjacent to one side in the circumferential direction, enters the rotor core 19 from the rotor side salient pole 20, and from the rotor side salient pole 20 adjacent to the other side in the circumferential direction to the stator side salient pole. A magnetic flux returning to 17 is generated. A magnetic attraction force acts between the stator side salient pole 17 and the rotor side salient pole 20, the rotor core 19 rotates, and the rotor side salient pole 20 faces the stator side salient pole 17. Stop in position. At this time, when the rotor-side salient pole 20 and the stator-side salient pole 17 face each other in the radial direction, the cogging torque becomes zero, and the rotor-side salient pole 20 and the stator-side salient pole 17 become circumferential. The greater the deviation, the greater the cogging torque. Therefore, torque pulsation is generated between the rotor core 19 and the stator core 16 according to the relative position between the rotor-side salient pole 20 and the stator-side salient pole 17.

This motor holding brake is attached to the motor by attaching the brake mechanism 1A to the motor rotating shaft 2. When the motor stop signal is received, a direct current is supplied to the coil 18 from the direct current power source 9, and the motor rotating shaft 2 is held by the magnetic attractive force between the stator side salient pole 17 and the rotor side salient pole 20. Stopped. When the motor operation signal is received, the energization of the coil 18 by the DC power source 9 is stopped, the magnetic attractive force between the stator side salient pole 17 and the rotor side salient pole 20 is lost, and the motor rotating shaft 2 That is, the motor is operated smoothly.
Therefore, also in the fourth embodiment, the same effect as in the first embodiment can be obtained.

Embodiment 5. FIG.
FIG. 11 is a schematic diagram illustrating a motor holding brake according to Embodiment 5 of the present invention.
In FIG. 11, a motor holding brake is configured such that a constant current for generating a braking force is supplied to a cylindrical coil 8 by receiving a motor stop signal and a brake mechanism unit 1 including a rotor core 3 and a stator 5. The control means 21 for controlling the DC power source 9 so as to energize the cylindrical coil 8 with a constant current for detecting the rotational position of the motor rotating shaft 2 in response to the operation signal, and the impedance change due to the rotation of the rotor core 3 A comparator 22 that compares the voltage value with a threshold value from the threshold value generation circuit 23 and outputs an encoder pulse 24 to the motor CPU 25; The DC power supply 9 corresponds to first and second power supply means.

  This motor holding brake is attached to the motor by mounting the brake mechanism 1 to the motor rotating shaft 2. When the control means 21 receives the motor stop signal, a constant current for generating a braking force is applied to the cylindrical coil 8 from the DC power supply 9. As a result, the motor rotating shaft 2 is held and stopped by the magnetic attractive force between the rotor-side salient pole 4 and the stator-side salient pole 7.

  When the control means 21 receives the operation signal of the motor, the constant current for detecting the rotational position of the motor rotating shaft 2 is supplied from the DC power source 9 to the cylindrical coil 8. Then, the rotor core 3 is rotated by the rotating operation of the motor, that is, the rotating operation of the motor rotating shaft 2. The inductance of the cylindrical coil 8 changes according to the relative position of the rotor core 3 (rotor side salient pole 4) and the stator core 6 (stator side salient pole 7). Then, as shown in FIG. 12, the voltage value generated at both ends of the cylindrical coil 8 changes in accordance with the change in inductance. The comparator 22 compares the voltage value change generated at both ends of the cylindrical coil 8 with the threshold value from the threshold value generation circuit 23 and outputs an encoder pulse 24. The motor CPU 25 receives the encoder pulse 24 and outputs position information such as the number of rotations and the movement distance of the motor.

As described above, according to the fifth embodiment, in addition to the effects of the first embodiment, position information of the motor rotating shaft 2 can be output with a simple configuration. Therefore, by attaching the motor holding brake to the motor, it is possible to obtain position information such as the number of rotations and the movement distance of the motor without using a rotational position sensor which has been conventionally required.
In the first embodiment, a constant current is applied to the cylindrical coil 8 and an inductance change is detected as a voltage value change generated at both ends of the cylindrical coil 8. However, a constant voltage is applied to the cylindrical coil 8. The inductance change may be detected as a current value change generated in the cylindrical coil 8. In this case, in addition to the DC power supply 9, a constant voltage power supply as a second power supply means is provided.

  In the second to fifth embodiments, the case where the rotor side salient pole 4 and the stator side salient pole 7 are formed at the same equiangular pitch to have the same number of salient poles is described. The same applies even if the number of salient poles of the rotor side salient pole 4 and the stator side salient pole 7 is different by changing the arrangement pitch.

It is a figure explaining the structure of the brake for motor holding which concerns on Embodiment 1 of this invention. It is a partially broken perspective view explaining the structure of the brake mechanism part in the brake for motor holding which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the stator core and rotor core which comprise the brake for motor holding concerning Embodiment 1 of this invention. It is a figure explaining the assembly method of the stator in the brake for motor holding concerning Embodiment 1 of this invention. It is a wave form diagram which shows the torque pulsation in the brake for motor holding which concerns on Embodiment 1 of this invention. It is a figure which shows the frequency characteristic of the brake for motor holding | maintenance which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the brake mechanism part in the brake for motor holding | maintenance which concerns on Embodiment 2 of this invention. It is sectional drawing which shows the brake mechanism part in the brake for motor holding | maintenance which concerns on Embodiment 3 of this invention. It is a figure which shows the torque pulsation in the brake for motor holding concerning Embodiment 3 of this invention. It is a schematic diagram explaining the brake for motor holding which concerns on Embodiment 4 of this invention. It is a schematic diagram explaining the brake for motor holding which concerns on Embodiment 5 of this invention. It is a figure which shows the current waveform and voltage waveform in the brake for motor holding concerning Embodiment 5 of this invention.

Explanation of symbols

  3, 14, 19 Rotor core, 4, 15, 20 Rotor side salient pole, 4a, 15a First rotor side salient pole, 4b, 15b Second rotor side salient pole, 5 Stator, 6, 11, 16 Stator core, 7, 12, 17 Stator side salient pole, 7a, 12a First stator side salient pole, 7b, 12b Second stator side salient pole, 8 cylindrical coil (stator coil), 9 DC power supply (First power supply means), 18 coils (stator coil), 21 control means, 22 comparator, 23 threshold generation means, 24 encoder pulse.

Claims (6)

A rotor core that is manufactured in a thick cylindrical shape and that has a plurality of rotor-side salient poles projecting on the outer peripheral wall surface at a first equiangular pitch in the circumferential direction and coaxially fixed to the rotation shaft;
A plurality of stator-side salient poles projecting on the inner peripheral wall surface at a second equiangular pitch in the circumferential direction, and having a constant gap with respect to the rotor core; A stator core disposed around the outer periphery of the core;
A stator coil wound around the stator core;
First power supply means for passing a direct current through the stator coil,
A motor holding brake, wherein a torque pulsation corresponding to a rotational position of the rotor core is generated by applying a direct current to the stator coil by the first power supply means. In the motor holding brake according to claim 1,
Each of the rotor-side salient poles is composed of first and second rotor-side salient poles separated by a predetermined distance in the axial direction,
Each of the stator side salient poles is composed of first and second stator side salient poles spaced apart by a predetermined distance in the axial direction,
The stator coil is composed of a cylindrical coil produced by winding a conductor wire in a cylindrical shape a predetermined number of times, and is wound around the stator core between the first and second stator side salient poles. A brake for holding a motor.   2. The motor holding brake according to claim 1, wherein the stator coil is formed by winding a conductor wire around each of the plurality of stator side salient poles sequentially around the stator side salient poles a predetermined number of times. A motor holding brake characterized by comprising a coil. The brake for holding a motor according to any one of claims 1 to 3,
Second power supply means for applying a constant current or a constant voltage to the stator coil, and generating a voltage value change or a current value change in the stator coil according to the rotational position of the rotor core;
Threshold generating means for generating a threshold;
A comparator that compares the voltage value change or current value change according to the rotational position of the rotor core with the threshold value generated by the threshold value generation means and outputs an encoder pulse; Motor holding brake.   5. The motor holding brake according to claim 1, wherein the first equiangular pitch and the second equiangular pitch are the same. . The brake for holding a motor according to any one of claims 1 to 5,
The least common multiple of the number of salient poles on the rotor side and the number of salient poles on the stator side is P, the moment of inertia is J, and the amplitude of the cogging torque generated between the rotor side salient pole and the stator side salient pole. The resonance frequency f ₁ of the motor holding brake when τ ₁ is expressed by the equation (1), and the vibration angle in the frequency characteristic of the vibration angle of the motor holding brake when a disturbance having an amplitude F is applied. When the frequency f _{0 at} which is 2π / P is expressed by the equation (2),
Least common multiple P of the number of salient poles on the rotor side and the number of salient poles on the stator side, moment of inertia J, and amplitude τ of cogging torque generated between the rotor side salient pole and the stator side salient pole ₁ is set so as to satisfy f ₁ ≧ f _0. A motor holding brake characterized by the above.

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