JP2011223682A - Motor with electromagnetic brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor with an electromagnetic brake which reduces a leak magnetic flux to a rotor magnet.SOLUTION: The motor with an electromagnetic brake includes: a motor body 10 which includes a rotor 12 having a revolving shaft 2 made of a magnetic material and a rotor magnet 4, and a stator 11 having a driving coil 7; and an electromagnetic brake 1 which includes a rotating disk 1d movably fitted to the revolving shaft 2, an armature 1b provided in opposition to a rotating disk 1d movably in an axial direction, bias means for pressing the rotating disk 1d to a braking disk 1f via the armature 1b to perform a braking action, and an iron core yoke 1a for attracting the armature 1b in response to an excitation of an electromagnetic coil 1e. The electromagnetic coil 1e is divided into a main winding 1g wound around an outer diameter side of the iron core yoke 1a and a sub winding 1h wound around an inner diameter side while facing to the revolving shaft 2, and currents are respectively generated in the main winding 1g and the sub winding 1h in opposite directions, and the sub winding 1h is surrounded with the iron core yoke 1a, the revolving shaft 2, and the armature.

Description

  The present invention relates to an electric motor having a non-excitation operation type electromagnetic brake including an electric motor main body and an electromagnetic brake.

  Conventionally, a winding-embedded iron core yoke provided on the stator side, an armature that is attracted and moved by excitation of the iron core yoke, and a rotating circle that is provided on the rotor side and is moved by the armature to move in the axial direction of the rotor An electric motor with an electromagnetic brake having a plate is known.

  FIG. 2 is a longitudinal sectional view of a main part of a conventional electric motor 102 with an electromagnetic brake. In FIG. 2, an electromagnetic brake 1 is provided on one end side of the electric motor body 10. The electric motor main body 10 includes a stator 11 fixed to the bracket 3 and a rotor 12 that is rotatably disposed inside the stator 11. The stator 11 has a stator core 5 and a drive coil 7. On the other hand, the rotor 12 includes a rotating shaft 2 that is rotatably supported by a bearing 6 and a rotor magnet 4 disposed on an outer peripheral portion of the rotating shaft 2.

  The electromagnetic brake 1 is provided so as to be movable only in the axial direction opposite to one side surface of the rotating disc 1d and a rotating disc 1d that is fitted in the axial direction of the rotating shaft 2 via the center hub 1c. A disk-shaped armature 1b, a braking spring (not shown) that performs a braking action by pressing the rotating disk 1d against the other braking disk 1f through the armature 1b, and an electromagnetic coil 1e are embedded. The coil 1e has an annular iron yoke 1a that attracts the armature 1b against the urging force of the brake spring as the coil 1e is excited.

  In the electromagnetic brake 1 having such a configuration, the iron core yoke 1a in which the electromagnetic coil 1e is embedded and the armature 1b form a closed circuit. If the structure is adapted to miniaturization, there is magnetic saturation in a part of the iron core yoke 1a. As shown by the arrow in FIG. 2, the magnetic flux leaks along the path of the arrow so as to surround the iron core yoke 1a and the armature 1b. Thus, when the leakage magnetic flux from the electromagnetic brake 1 is generated and this leakage magnetic flux reaches the rotor magnet 4, the cogging torque may be adversely affected.

  FIG. 3 is a longitudinal sectional view of a main part of a conventional improved motor 103 with an electromagnetic brake. As a method for solving the problem caused by the leakage magnetic flux as described above, as shown in FIG. 3, two grooves are formed in the iron core yoke 1a of the electromagnetic brake 1, and the main winding 1g is embedded in the outer groove, The auxiliary coil 1h is embedded in the groove of the main coil 1g and the direction of the current flowing through the auxiliary coil 1h is opposite to each other, thereby leaking to the rotating shaft 2 inside the electromagnetic brake 1 A method for reducing the magnetic field has been proposed (see, for example, Patent Document 1).

Japanese Utility Model Publication No. 6-74066

  However, in the conventional method of embedding the main winding and the sub-winding in the two grooves, the outer diameter of the iron core yoke of the electromagnetic brake is increased for the sake of ensuring the magnetic path cross-sectional area of both windings. There was a problem that it could not cope with the conversion.

  The present invention has been made in view of the above, and can effectively reduce the leakage magnetic flux to the rotor magnet at the time of exciting the electromagnetic brake with a simple structure. An object of the present invention is to provide a non-excited operation type electric motor with an electromagnetic brake that can be made excellent in performance and quality.

  In order to solve the above-described problems and achieve the object, an electric motor with an electromagnetic brake according to the present invention includes a rotor having a rotor shaft disposed on an outer peripheral portion of a rotating shaft of the magnetic material and a rotating shaft, and the rotor. A stator having a drive coil for encircling and energizing the rotor, a rotating disc fitted in the axial direction so as to be movable on the rotating shaft, and one side surface of the rotating disc facing each other. A disk-shaped armature provided so as to be movable only in the axial direction, an urging means for performing a braking action by pressing the rotating disk against a braking disk facing the other side surface via the armature, and an electromagnetic coil An electromagnetic brake including an annular core yoke that attracts the armature against the urging force of the urging means with excitation, and the electromagnetic coil includes a main winding wound on the outer diameter side of the iron yoke Of iron core yoke It is divided into a secondary winding wound on the radial side so as to face the rotary shaft, and a current is passed through the main winding and the secondary winding so as to be opposite to each other. It is characterized by being surrounded by a rotating shaft and an armature.

  According to the present invention, the electromagnetic coil is divided into a main winding wound around the outer diameter side of the iron core yoke and a sub-winding wound around the inner diameter side of the iron core yoke so as to face the rotation shaft. Current is passed through the winding and the sub-winding in opposite directions, and the sub-winding is surrounded by the iron core yoke, the rotating shaft, and the armature. Is used to form a magnetic circuit that passes through the armature and returns to the iron core yoke. As a result, the leakage magnetic flux that flows from the iron yoke and armature of the electromagnetic brake to the rotor magnet of the motor body can be directly canceled by the magnetic field created by the auxiliary winding. It can be an attached electric motor.

FIG. 1 is a longitudinal sectional view of an essential part of an embodiment of an electric motor with an electromagnetic brake according to the present invention. FIG. 2 is a cross-sectional view of a main part of a conventional electric motor with an electromagnetic brake. FIG. 3 is a cross-sectional view of a main part of another conventional electric motor with an electromagnetic brake.

  Embodiments of an electric motor with an electromagnetic brake according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment.
FIG. 1 is a longitudinal sectional view of an essential part of an embodiment of an electric motor with an electromagnetic brake according to the present invention. The electric motor 101 with an electromagnetic brake according to the present embodiment includes an electric motor main body 10 and an electromagnetic brake 1 provided on one end side of the electric motor main body 10. The electric motor main body 10 includes a stator 11 fixed to the bracket 3 and a rotor 12 that is rotatably disposed inside the stator 11.

  The stator 11 includes a stator core 5 having a substantially cylindrical shape, and a drive coil 7 wound around the stator core 5. On the other hand, the rotor 12 includes a rotating shaft 2 that is rotatably supported by a bearing 6 and a rotor magnet 4 that is a permanent magnet disposed on an outer peripheral portion of the rotating shaft 2. The bracket 3 is made of, for example, aluminum which is a nonmagnetic material, and the rotating shaft 2 is made of, for example, steel which is a magnetic material.

  The electromagnetic brake 1 includes a rotating disc 1d fitted so as to be movable in the axial direction of the rotating shaft 2 by a center hub 1c fitted to the rotating shaft 2, and an axial direction facing only one side surface of the rotating disc 1d. A disk-shaped armature 1b provided so as to be movable, and a braking spring (biasing means) (not shown) that performs a braking action by pressing the rotating disk 1d against the braking disk 1f facing the other side surface via the armature 1b. And an electromagnetic coil 1e is wound, and an annular iron yoke 1a that attracts the armature 1b against the urging force of the braking spring as the electromagnetic coil 1e is excited.

  The electromagnetic coil 1e according to the present embodiment has a main winding 1g wound in a groove formed on the outer diameter side of the iron core yoke 1a and a one-step inner diameter over the entire circumference of the inner circumference of the iron core yoke 1a. It is divided into sub-windings 1h wound with notches (steps) formed to be large. It exposes facing the space where the auxiliary winding 1h and the rotating shaft 2 are arranged, and faces the rotating shaft 2. The auxiliary winding 1h is disposed so as to be surrounded by the iron core yoke 1a, the rotating shaft 2 and the armature 1b, and forms a magnetic circuit at these portions.

  The operation will be described. The electromagnetic brake 1 performs a braking action by pressing a rotating disk 1d against a braking disk 1f opposite to the other side surface via an armature 1b with a braking spring (not shown). When the electromagnetic coil 1e is excited in this state, The armature 1b is attracted against the urging force of the braking spring by the electromagnetic attraction force of the armature 1b, and the braking surface is pulled apart to release the brake.

  In FIG. 1, the flow of magnetic flux generated from the electromagnetic brake 1 is indicated by a dotted arrow. When the electromagnetic brake 1 is energized, as described above, the armature 1b is attracted to the iron core yoke 1a, and the rotating disc 1d is released from the restraint with the braking disc 1f and the brake is released. According to the present embodiment, the electromagnetic coil 1e is divided into a main winding 1g and a sub winding 1h, a notch is provided on the inner diameter side of the iron core yoke 1a, and the sub winding 1h is disposed there. The line 1h is energized in the direction opposite to the main winding 1g. In this state, most of the leakage magnetic flux generated from the electromagnetic brake 1 flows to the rotating shaft 2 as shown by an arrow in FIG. 1, and then returns to the iron core yoke 1a through the armature 1b. Thereby, the magnetic flux which advances to the rotor magnet 4 through the rotating shaft 2 decreases sharply, and the influence of leakage magnetic flux can be reduced.

  Further, since the magnetic field generated by the auxiliary winding 1h uses the rotary shaft 2 as a direct magnetic path, the above-described effect can be obtained with the auxiliary winding 1h having a smaller number of turns than the main winding 1g. That is, the number of turns of the sub-winding 1h is such that the leakage magnetic field generated in the rotor magnet 4 due to the excitation of the main winding 1g is canceled by the magnetic field generated by the sub-winding 1h and disappears. . And since the leakage magnetic flux which flows into the rotor magnet 4 can be directly canceled with the magnetic field which the subwinding 1h produces, the leakage magnetic flux to the rotor magnet 4 can be made small with a small iron core yoke outer diameter size.

  As described above, in the electric motor with electromagnetic brake 101 of the present embodiment, the electromagnetic coil 1e includes the main winding 1g wound around the outer diameter side of the iron core yoke 1a and the rotating shaft on the inner diameter side of the iron core yoke 1a. 2 is divided into a sub-winding 1h wound opposite to the main winding 1g, and a current is passed through the main winding 1g and the sub-winding 1h in opposite directions. Since the rotary shaft 2 and the armature 1b are surrounded, the auxiliary winding 1h forms a magnetic circuit that returns from the iron core yoke 1a to the iron core yoke 1a via the rotary shaft 2 through the armature 1b. As a result, the leakage magnetic flux flowing from the iron core yoke 1a and armature 1b of the electromagnetic brake 1 to the rotor magnet 4 of the electric motor body 10 can be directly canceled by the magnetic field generated by the auxiliary winding 1h. An electric motor with an electromagnetic brake having excellent quality can be obtained.

  As described above, the electric motor with an electromagnetic brake according to the present invention is useful for an electric motor with an electromagnetic brake used in various industrial equipment, and in particular, an electric motor with an electromagnetic brake used as a drive source for a robot or an NC machine tool. Suitable for

DESCRIPTION OF SYMBOLS 1 Electromagnetic brake 1a Iron core yoke 1b Armature 1c Center hub 1d Rotating disk 1e Electromagnetic coil 1f Braking disk 1g Main winding 1h Subwinding 2 Rotating shaft 3 Bracket 4 Rotor magnet 5 Stator core 6 Bearing 7 Drive coil 10 Motor body 11 Stator 12 Rotor 101, 102, 103 Electric motor with electromagnetic brake

Claims (3)

A rotor having a rotating shaft made of a magnetic material and a rotor magnet disposed on an outer periphery of the rotating shaft; and a stator having a drive coil surrounding the rotor and rotatingly urging the rotor. An electric motor body,
A rotating disk fitted to the rotating shaft so as to be movable in the axial direction; a disk-shaped armature provided so as to be movable only in the axial direction facing one side surface of the rotating disk; and via the armature And an urging means for performing a braking action by pressing the rotating disk against a braking disk opposite to the other side surface, and an annular shape for attracting the armature against the urging force of the urging means when the electromagnetic coil is excited. An iron core yoke, and an electromagnetic brake comprising
The electromagnetic coil is divided into a main winding wound on the outer diameter side of the iron core yoke and a sub-winding wound on the inner diameter side of the iron core yoke facing the rotation shaft,
A current is passed through the main winding and the sub-winding in opposite directions,
The sub-winding is surrounded by the iron core yoke, the rotating shaft, and the armature. The iron core yoke forms a step portion that increases the inner diameter of the first step over the entire circumference,
The electric motor with an electromagnetic brake according to claim 1, wherein the auxiliary winding is wound around the stepped portion. The number of turns of the sub-winding is a number of turns in which a leakage magnetic field generated in the rotor magnet due to excitation of the main winding is canceled out by the magnetic field created by the sub-winding. The electric motor with an electromagnetic brake according to 1 or 2.

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