JP4952955B2 - Non-excitation actuated electromagnetic brake and motor equipped with the same - Google Patents

Description

    The present invention relates to a non-excitation operation type electromagnetic brake which is attached to a motor which is a drive source of an industrial robot or the like and is used for maintaining a braking or stopping state of a motor rotation shaft and a motor including the same.

A motor is used as a drive source of a robot used in the field of automobiles and semiconductors, and a non-excitation operation type electromagnetic brake for braking the rotation of the motor is mounted as a safety device.
FIG. 5 shows a side sectional view of a conventional motor with an electromagnetic brake. The electromagnetic brake includes a field core 1 made of a soft magnetic material, a coil 3 wound around the field core 1 via an insulator 2, and a compression coil spring 4 attached to the field core 1 in the axial direction. An armature 5 in axial contact with the compression coil spring 4, a side plate 7 fixed to the field core 1 through a collar 6, and a brake disk 8 disposed between the armature 5 and the side plate 7 The hub 9 is fitted to the brake disc 8 so as to be freely movable in the axial direction, and the friction plate 10 is attached to both surfaces of the brake disc 8. The electromagnetic brake is fixed to the motor bracket 20 via the field core 1 with a bolt (not shown). Further, the rotating shaft 21 of the motor is connected to the brake disc 8 via the hub 9.

    In the electromagnetic brake having such a conventional structure, in the non-excited state, the armature is pressed to the side plate side by the elastic force of the compression coil spring, so that the brake disk is braked for rotation by the frictional force between the armature and the side plate. Therefore, the rotating shaft of the motor is held stationary and functions as a safety brake. On the other hand, in the energized state in which the electromagnetic coil is energized, the armature is magnetically attracted to the field core against the elastic force of the compression coil spring, and between the armature and the brake disc friction plate, and between the brake disc friction plate and the side plate. Is released, the braking state is released, and the rotating shaft of the motor becomes rotatable.

In such a conventional electromagnetic brake, when the brake disk is in an excited state, that is, when the brake disk is opened and rotated, the brake disk can freely move in the axial direction, so the friction plate and the armature, and the friction plate and the side plate may come into contact with each other. There is a problem that the friction plate, the armature and the side plate are worn during the contact.
In order to solve this problem, non-excitation actuated electromagnetic brakes that prevent wear of brake discs and the like are disclosed in JP-A-11-230203 (Prior Art 1) and JP-A 2000-39041 (Prior Art 2). .

  In these prior arts, the non-excited operation type electromagnetic brake of Prior Art 1 prevents wear by adjusting the gaps formed between the armature and the brake disc and between the brake disc and the side plate. That is, it has a gap adjusting mechanism and adjusts the air gap between the field core and the armature and the gap between the brake disk and the side plate.

Further, in the non-excited operation type electromagnetic brake of Prior Art 2, the brake disk is provided on the synthetic resin brake disk main body and both side surfaces of the brake disk main body to increase the adhesive strength at least on the wall surface serving as the adhesive surface. The structure is provided with an annular groove that has been subjected to the above surface treatment, a lining that is fitted into the annular groove and fixed with an adhesive, and that protrudes from the side surface of the brake disc body, thereby preventing wear.
JP-A-11-230203 JP 2000-39041 A

The non-excited operation type electromagnetic brake of Prior Art 1 has an adjustment mechanism for adjusting the gap between the armature and the field core and the gap between the brake brake disk and the side plate, but the adjustment mechanism is complicated. Yes, it was necessary to adjust the gap of about 0.1-0.5mm with 0.1mm accuracy, and it took a long time. Moreover, since there are many parts which comprise an adjustment mechanism, it was expensive.
In the non-excited operation type electromagnetic brake of Prior Art 2, the armature and the friction plate and the friction plate and the side plate may come into contact with each other when the brake disk moves freely in the axial direction even during rotation. Due to the heat generated at the time of contact, there is a problem that the resin brake disc is deformed and the braking force is weakened or damaged.
The present invention has been made in view of such problems. Even when the armature and the friction plate or the friction plate and the side plate are in contact with each other while the brake disk is rotating, the friction plate, the armature and the side plate are provided. An object of the present invention is to provide an electromagnetic brake capable of preventing the wear of a plate and a motor including the same.

In order to solve the above problems, the present invention is configured as follows.
The invention according to claim 1 is a field core formed of a soft magnetic material, a coil wound around the field core via an insulator, a compression coil spring attached to the field core in an axial direction, An armature that is in axial contact with the compression coil spring; a side plate that is fixed to the field core via a collar; and a brake disk that is arranged to be sandwiched between the armature and the side plate by the axial force of the compression coil spring; In an electromagnetic brake having a hub fitted so as to be able to move freely in the axial direction with a brake disc, and a friction plate attached to both sides of the brake disc, a non- A gap variation tracking device composed of a magnetic ball, cage and spring is equally spaced on the circumference of the brake disc. In and is obtained by alternately arranged on both sides of the brake disc.

  According to a second aspect of the present invention, an even number of four or more adjusting mechanisms are alternately arranged on both side surfaces of the brake disc.

  According to a third aspect of the present invention, the spring of the gap variation following device is a leaf spring.

  According to a fourth aspect of the present invention, the friction plate is formed into a disc shape having a hollow portion, and the gap variation tracking device is disposed in the hollow portion of the friction plate.

  A fifth aspect of the present invention is a motor comprising the non-excitation operation type electromagnetic brake according to any one of the first to fourth aspects.

When the conventional electromagnetic brake is energized, the brake disc is released, swings in the direction of the rotation axis, and the armature, friction plate, and side plate wear due to friction when the armature, friction plate, friction plate, and side plate are in direct contact. Was.
According to the first aspect of the present invention, since the ball is in contact with the armature and the side plate by the elastic force of the spring even when the electromagnetic brake is in an excited state, that is, when the disc brake is released, the friction plate maintains a certain gap in the axial direction. And wear of the armature, side plate and friction plate can be prevented. Even if the gap between the armature and the friction plate and between the friction plate and the side plate fluctuates, the nonmagnetic sphere contacts the armature and the side plate due to the elastic force of the spring, so the armature and the friction plate and / or the friction plate and the side plate The plate is not in direct contact, and wear of the armature, friction plate, and side plate can be prevented.

  According to the second aspect of the present invention, the elastic force of the spring is alternately distributed evenly on the circumference of the brake disk and alternately on the armature side and the side plate side. Are arranged so as to work, the total elasticity of the springs acting on the armature side and the side plate side are equal and balanced. Therefore, the gap between the armature and the friction plate and between the friction plate and the side plate can be kept constant and stable. For this reason, the brake disc does not fall down and local wear does not occur, leading to a longer life of the electromagnetic brake.

  According to the third aspect of the present invention, when the electromagnetic brake is in an excited state, that is, when the brake disc is opened and rotating, the brake disc swings in the axial direction, and the gap between the armature, the brake disc, and the side plate Even when the fluctuations occur, the gap between the armature, the brake disc, and the side plate can be kept constant by smoothly following the gap fluctuation by the elastic force of the leaf spring. For this reason, the armature and the friction plate and the friction plate and the side plate do not come into contact with each other, and wear due to friction of these components is eliminated, leading to a longer life of the electromagnetic brake.

  According to the fourth aspect of the present invention, the friction plate is formed into a disk shape, the inside where the friction generating force is small is hollowed, and the gap variation following device is disposed in the hollow portion, thereby reducing the friction force during braking. In addition, when the brake is released, the armature, the friction plate, and the side plate can be prevented from being worn, and the life of the electromagnetic brake can be extended.

  According to the fifth aspect of the present invention, it is possible to provide a non-excited operation type electromagnetic brake that prevents wear of a mechanical part that generates a braking force. Therefore, it is possible to provide a highly reliable and long-life motor with an electromagnetic brake. it can.

Hereinafter, specific examples of the present invention will be described.

  FIG. 1 is a side sectional view showing a part of a first embodiment of a non-excitation operation type electromagnetic brake motor according to the present invention, and FIG. 2 is a front view of a brake disk as seen from the side plate side. FIG. 3 is a cross-sectional view taken along the line A-A 'of FIG. 2 when the armature is attracted to the field core side by the electromagnetic brake in an excited state, that is, by a magnetic attractive force, and the brake disk is released. 4 is a cross-sectional view taken along the line A-A ′ of FIG. 2 when the electromagnetic brake is in a non-excited state, that is, when the brake disk is pressed against the side plate by the compression coil.

FIG. 1 shows the positional relationship of component parts in an excited state of a motor with an electromagnetically actuated electromagnetic brake according to the present invention, that is, a state where a brake disk is freely rotating.
The electromagnetic brake is fixed to the motor bracket 20 via the field core 1 with bolts (not shown). The rotating shaft 21 of the motor is connected to the brake disc 8 via the hub 9. The electromagnetic brake includes a field core 1 made of a soft magnetic material, a coil 3 wound around the field core 1 via an insulator 2, a compression coil spring 4 attached to the field core 1 in the axial direction, An armature 5 in axial contact with the compression coil spring 4; a side plate 7 fixed to the field core 1 via a collar 6; a brake disc 8 disposed so as to be sandwiched between the armature 5 and the side plate 7; It consists of a hub 9 fitted so as to be able to move freely in the axial direction with the disk 8. Disc-shaped friction plates 10 are attached to both side surfaces of the brake disc 8. Further, gap fluctuation followers 14 are arranged at equal intervals in the circumferential direction on the inner peripheral side of the friction plate 10. That is, two pieces are arranged on the armature side and two pieces on the side plate side at a 90-degree interval.
The armature 5 is attracted to the field core 1 side against the elastic force of the compression coil spring 4 by a magnetic attractive force, and is between the friction plate 10 and the armature 5 and between the friction plate 10 and the side plate 7. A gap δ is generated. Further, the sphere 11 of the gap variation follower 14 is in contact with the armature 5 or the side plate 7.

  FIG. 2 shows a front view of the brake disc 8 as seen from the side plate 7 side. The brake disc 8 has a square hole through which the hub 9 penetrates at the center, and a hollow disc-shaped friction plate 10 is attached to the outer peripheral portions of both side surfaces. Further, four gap adjusting mechanism non-magnetics 14 are alternately arranged on the inner peripheral portion of the friction plate 10 at equal intervals in the circumferential direction and on both side surfaces. 3 and 4 show the details of the gap fluctuation tracking device 14. FIG. 3 is a cross-sectional view when the brake is released (excitation), and FIG. 4 is a cross-sectional view when the brake (non-excitation). The ball 11 is supported by the cage 12 and is in contact with the armature 5 and the side plate 7 by the elastic force of the leaf spring 13.

With reference to FIG. 3, the action of the gap variation tracking device 14 in the excited state, that is, when the brake is released, which is the point of the present invention, will be described in detail.
The armature 5 is attracted to the field core 1 against the elastic force of the compression coil spring, and a gap δ is generated between the armature 5 and the friction plate 10 and between the friction plate 10 and the side plate 7. For this reason, the brake disc 8 connected to the rotating shaft 21 of the motor via the hub 9 can freely rotate.
In addition, when the brake disk 8 is about to move in the axial direction during rotation, the elastic force of the leaf spring of the gap variation following device 14 absorbs the axial variation of the brake disk 8. Accordingly, the gaps between the field core 1 and the friction plate and between the friction plate and the side plate 7 are automatically maintained, and there is no contact between the armature 5 and the friction plate 10 and between the side plate 7 and the friction plate 10. 10, The problem that the armature 5 and the side plate 7 are worn out does not occur.

In the case of excitation, an exciting current is caused to flow through the coil 3 to generate a magnetic attractive force, and the armature 5 is drawn toward the field core 1 against the elastic force of the compression coil spring 4, but in order to reduce the exciting current, the side plate 7 and the armature 5 are made of iron-based material. In addition, a non-magnetic metal material is used for the ball 11, the leaf spring 13, and the brake disk 8, and a self-lubricating resin material is used for the cage 12, so that magnetic attraction force does not act on these parts. ing. This prevents the generation of an unbalanced magnetic attractive force that causes the swinging rotation of the brake disk 8.
FIG. 4 shows a cross-sectional view of the brake disc in a non-excited state, that is, during a braking operation. In this case, since the armature 5 is pressed against the side plate 7 by the elastic force of the compression coil spring 4, the side plate 7 and the friction plate 10 are pressed against each other, and the rotation of the brake disk 8 is braked by the friction force. At this time, the leaf spring 13 of the gap variation tracking device 14 is elastically deformed, and the ball 11 is in contact with the armature 5 and the side plate 7. Accordingly, the action of the brake disk 8 in the non-excited state is the same as that of the conventional electromagnetic brake, and has a braking force equal to or higher than that of the conventional electromagnetic brake.

  In place of the nonmagnetic sphere 11, a nonmagnetic roller may be used. Further, instead of the metal plate spring 13, a plate spring formed of a resin material may be used. Since the leaf spring formed of the resin material can be integrated with the cage 12, it is easy to reduce the size and weight compared to the metal leaf spring.

Side sectional view showing structure of motor with electromagnetic brake of the present invention The front view which shows the structure of the brake disc seen from the side plate side of this invention Sectional view (excited state) of A-A 'of the brake disc of the present invention A-A 'sectional view of the brake disc of the present invention (non-excited state) Side view of a conventional electromagnetic brake

Explanation of symbols

1 Field Core 2 Insulator 3 Coil 4 Compression Coil Spring 5 Armature 6 Collar 7 Side Plate 8 Brake Disc 9 Hub 10 Friction Plate 11 Ball 12 Cage 13 Plate Spring 14 Gap Fluctuation Tracking Device 20 Bracket 21 Rotating Shaft

Claims (5)

A field core formed of a soft magnetic material, a coil wound around the field core via an insulator, a compression coil spring attached to the field core in the axial direction, and an axial contact with the compression coil spring An armature, a side plate fixed to the field core via a collar, a brake disk arranged to be sandwiched between the armature and the side plate by the axial force of the compression coil spring, and the brake disk move freely in the axial direction. In a non-excited operation type electromagnetic brake having a hub fitted so as to be able to be attached, and a friction plate attached to both surfaces of the brake disk,
Non-excited operation type characterized in that gap fluctuation tracking devices composed of non-magnetic balls, cages and springs are alternately arranged on the circumference of the brake disc at equal intervals and on both sides of the brake disc. Electromagnetic brake.   2. The non-excited operation type electromagnetic brake according to claim 1, wherein an even number of four or more gap variation following mechanisms are alternately disposed on both side surfaces of the brake disk.   The non-excitation actuated electromagnetic brake according to claim 1 or 2, wherein the spring of the gap variation following device is a leaf spring.   The non-excitation according to any one of claims 1 to 3, wherein the friction plate has a disk shape having a hollow portion, and the gap variation follower is disposed in the hollow portion of the friction plate. Actuated electromagnetic brake.   A motor comprising the non-excitation actuating electromagnetic brake according to any one of claims 1 to 4.

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