JPH11294504A - Non-exciting actuation type electromagnetic brake - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a adsorption force for an armature when a magnetic ring is set to a demagnetization position, and release a braking easily even if an exciting coil is not energized. SOLUTION: An armature 24 which is movable in an axial direction is attached to a braked rotating shaft 21, a permanent magnet 13a to which the armature 24 is attracted and an exciting coil 13b which offsets a magnetic flux of the permanent magnet 13a by energizing are located to a fixing part 10, and a magnetic ring 15 which is movable in an axial direction between a demagnetization position and a non-demagnetization position is provided at an outer periphery of a magnet assembly 13. When the magnetic ring 15 is set to the demagnetization position, a magnetic path of the permanent magnet 13a is short-circuited to damp the adsorption force for the armature 24. Magnetic resistance of the magnetic path of the permanent magnet 13a at the non- demagnetization position of the magnetic ring 15 is set greater than that of a magnetic path Y at the demagnetization position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-excited operation type electromagnetic brake, and more particularly to an electromagnetic brake capable of releasing a braking operation without energizing an excitation coil.

[0002]

2. Description of the Related Art A conventional non-excited operation type electromagnetic brake of this type is constructed as shown in, for example, Japanese Utility Model Laid-Open Publication No. 58-150638. FIGS. 4 and 5 are half vertical sectional side views showing a conventional non-excited operation type electromagnetic brake disclosed in the publication. The fixed part A on the left side in the figure is composed of an exciting coil 1, a yoke 2, a main body plate 3, a permanent magnet 4, a stator 5, and a lining 6, and an armature 7 has a spring 8 Attached through. A magnetic ring 9 is attached to the outer periphery of the permanent magnet 4 so as to be slidable in the axial direction.

The magnetic ring 9 is axially movable between a degaussing position shown in FIG. 4 and a degaussing position shown in FIG.
This movement may be achieved by forming a screw that fits on the opposing surface of the magnetic ring 9 and the opposing permanent magnet and sliding the ball, or by sliding through a ball. When the magnetic ring 9 is set to the non-demagnetizing position shown in FIG. 4, the armature 7 is attracted to the lining 6 by the magnetic flux of the permanent magnet 4 in a state where the excitation coil 1 is not energized,
The braking action is exerted. On the other hand, when the excitation coil 1 is energized, the magnetic flux of the excitation coil 1 does not pass through the permanent magnet 4 and forms a magnetic path in the opposite direction so as to cancel the magnetic flux of the permanent magnet 4 acting on the armature 7. When the exciting current exceeds a certain value, the magnetic flux of the exciting coil 1 cancels the magnetic flux of the permanent magnet 4, the attractive force between the armature 7 and the stator 5 disappears, and the elastic force of the spring 8 reduces the armature 7.
Is released from the stator 5 and the braking is released.

When the magnetic ring 9 is set to the demagnetized position shown in FIG. 5, the magnetic path of the permanent magnet 4 is short-circuited, the magnetic flux acting on the armature 7 from the permanent magnet 4 is attenuated, and the excitation coil 1 is energized. It is possible to release the braking without the need.

[0005]

However, in the above-mentioned conventional non-excited operation type electromagnetic brake, the magnetic ring 9 is not provided.
Since there is no difference in magnetic resistance between the magnetic path of the permanent magnet 4 when the magnetic ring 9 is in the non-demagnetizing position and the magnetic path of the permanent magnet 4 when the magnetic ring 9 is set to the degaussing position, the magnetic ring 9 is demagnetized. Even if it is set at the position, the magnetic flux passing through the armature 7 cannot be completely canceled, and the attraction force is still acting between the armature 7 and the stator 5, so that the braking is performed without energizing the exciting coil 1. There was a problem that both had to be separated by a relatively large force in order to release. In order to increase the force acting for release, it is conceivable to increase the urging force of the spring 8, but if the urging force of the spring 8 is increased, there is a problem that the attraction force at the time of braking becomes weak.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and can reduce the attraction force to the armature when the magnetic ring is set at the degaussing position as compared with the prior art. It is an object of the present invention to provide a non-excited operation type electromagnetic brake that can easily release the braking without the need.

[0007]

A non-excited operation type electromagnetic brake according to the present invention comprises a fixed portion and a rotating portion having a rotating shaft to be braked rotatable with respect to the fixed portion. An armature that is movable in the axial direction is attached, and a magnet assembly having a permanent magnet that attracts the armature and an excitation coil that cancels out the magnetic flux of the permanent magnet by energization is disposed on the fixed portion, and is provided on the outer periphery of the magnet assembly. In a configuration in which a magnetic ring that can move in the axial direction between the degaussing position and the non-degaussing position is provided, and the magnetic ring is set to the degaussing position to short-circuit the magnetic path of the permanent magnet and attenuate the attraction force to the armature. The magnetic resistance of the magnetic path of the permanent magnet when the magnetic ring is set to the non-demagnetizing position is the magnetic resistance of the magnetic path of the permanent magnet when the magnetic ring is set to the degaussing position. Characterized in that set to be larger than the resistance.

Specifically, when a gap formed in the magnetic path of the permanent magnet is set at a position where the magnetic ring is demagnetized,
By setting the gap to be larger than the gap formed in the magnetic path, the difference in magnetic resistance can be set as described above.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the non-excited operation type electromagnetic brake according to the present invention will be described below. 1 to 3 show a non-excited operation type electromagnetic brake according to an embodiment of the present invention. FIG. 1 is a half longitudinal sectional side view showing a state in which braking is manually released, and FIG. 2 is a half longitudinal sectional view at the time of braking. FIG. 3 is a half longitudinal sectional side view showing a state in which braking is released by excitation.

As shown in FIG. 1, a non-excited operation type electromagnetic brake according to the present embodiment includes a fixed portion 10 and a rotating portion 20 having a braked rotary shaft 21 rotatable with respect to the fixed portion 10. Consists of A cylindrical hub 22 is integrally fixed to the braked rotary shaft 21, and a disk-shaped armature 24 is attached to the outer periphery of the hub 22 via a spring 23. The armature 24 is movable in the axial direction with respect to the rotation shaft 21 to be braked.
3 is always urged in a direction away from the fixed portion 10.

The fixed portion 10 has a through hole formed at the center so as to penetrate the braked rotary shaft 21. The fixed body 10 has a disc-shaped body plate 11 located at the left end in the figure and the braked rotary shaft 21. Cylindrical stator 12 provided around
And a magnet assembly 13 arranged on the outer periphery of the stator 12 and joined to the main body plate 11. The magnet assembly 13 is joined to the main body plate 11 and is a permanent magnet 13a for attracting the armature 24.
An excitation coil 13b disposed on the armature 24 side of the permanent magnet 13a and canceling the magnetic flux of the permanent magnet 13a by energization; And an L-shaped yoke 13c.

A lining 14 is mounted between the stator 12 and the yoke 13c on the rightmost side of the fixed portion 10 in the drawing so as to face the armature 24. Further, a cylindrical magnetic ring 15 is provided on the outer periphery of the magnet assembly 13, specifically, on the outer periphery of the permanent magnet 13 a and a part of the yoke 13 c and on the outer periphery of the main body plate 11. The magnetic ring 15 is set so as to be movable in the axial direction by a manual operation using a screw structure (not shown) or a structure including a ball bearing. The demagnetization position shown in FIG. 1 and the non-demagnetization position shown in FIGS. Switchable between positions.

When the magnetic ring 15 is set to the non-demagnetizing position as shown in FIG. 2, the magnetic flux of the permanent magnet 13a causes the body plate 11, the stator 12, the armature 24, First through the yoke 13c
Is formed. The armature 2
4 is attracted to the fixed part 10 side.

On the other hand, when the magnetic ring 15 is set at the degaussing position as shown in FIG. 1, the magnetic flux of the permanent magnet 13a causes a part of the body plate 11 and a part of the yoke 13c as shown by the broken line in the figure. And the second magnetic path Y is formed. It should be noted that the first magnetic path X shown in FIG.
A first gap G1 is formed between the magnetic ring 15 and the stator 12, and a second gap G2 is formed between the magnetic ring 15 and the yoke 13c in the second magnetic path Y shown in FIG. . Here, the first gap G1 is set to be larger than the second gap G2, and the magnetic resistance of the first magnetic path X becomes larger than the magnetic resistance of the second magnetic path Y. Therefore, when the magnetic ring 15 is set to the demagnetizing position, the magnetic flux of the permanent magnet 13a is short-circuited by the second magnetic path Y, and the magnetic flux passing through the first magnetic path X is extremely small.

Next, the operation of the non-excitation operation type electromagnetic brake configured as described above will be described. First, a case where the magnetic ring 15 is set at the non-demagnetizing position as shown in FIGS. 2 and 3 will be described. Excitation coil 13b
When no current is supplied to the armature 2, the magnetic flux of the permanent magnet 13 a passing through the first magnetic path X as shown in FIG.
4 is attracted to the fixed part 10 side, and a braking action is exerted by frictional resistance between the armature 24 and the lining 14.

When the exciting coil 1 is energized, as shown in FIG. 3, the magnetic flux of the exciting coil 13b
A third magnetic path Z passing through the armature 24 and the stator 12 is formed. The magnetic flux of the exciting coil 13b passing through the third magnetic path Z is in the opposite direction to the magnetic flux of the permanent magnet 13a passing through the first magnetic path X, and the magnetic flux of the exciting coil 13b acts on the armature 24. Acts to cancel out. When the exciting current becomes a certain value or more, the magnetic flux of the permanent magnet 13a is canceled by the magnetic flux of the exciting coil 13b, the attractive force between the armature 24 and the lining 14 disappears, and the armature 24 is The brake is released by separating from the lining 14.

When the magnetic ring 15 is set at the demagnetized position shown in FIG. 1, the magnetic flux of the permanent magnet 13a is changed to the second magnetic path Y.
As a result, the magnetic flux acting on the armature 24 from the permanent magnet 13a through the first magnetic path X shown in FIG. 3 is attenuated, and the braking can be released without energizing the exciting coil 13b. At this time, since the magnetic resistance of the first magnetic path X is set to be larger than the magnetic resistance of the second magnetic path Y, the effect of the short circuit when the magnetic ring 15 is set to the degaussing position is large, Armature 24 through magnetic path X
Is extremely small as compared with the conventional example.
Accordingly, the armature 24 and the fixing portion 10 can be easily separated from each other with a relatively small force.
It is not necessary to increase the urging force of No. 3 and the braking force can be secured.

[0018]

Since the non-excited operation type electromagnetic brake of the present invention is constructed as described above, it has the following excellent effects. The magnetic resistance of the magnetic path of the permanent magnet when the magnetic ring is set to the degaussing position is determined by the magnetic resistance of the magnetic path of the permanent magnet when the magnetic ring is set to the degaussing position. If the resistance is set higher than the resistance, the magnetic resistance of the magnetic path that is short-circuited when the magnetic ring is set to the degaussing position will be smaller than the magnetic resistance of the magnetic path when the magnetic ring is set to the non-degaussing position. Further, the attraction force to the armature at the time of short circuit can be made smaller than before. Therefore, since the braking can be easily released with a small force without energizing the exciting coil, there is no need to set a large urging force of the spring for return, and a predetermined braking force can be secured. The gap of the magnetic path formed in the magnetic path of the permanent magnet is larger than the gap formed in the magnetic path when the magnetic ring is set to the degaussing position. By setting, there is a practical advantage that it can be realized with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a half vertical sectional side view showing a state in which braking is manually released from a non-excitation operation type electromagnetic brake according to an embodiment of the present invention.

FIG. 2 is a half vertical sectional side view of the non-excitation operation type electromagnetic brake shown in FIG. 1 during braking.

FIG. 3 is a half vertical sectional side view showing a state in which braking is released by excitation of the non-excitation operation type electromagnetic brake shown in FIG. 1;

FIG. 4 is a half vertical sectional side view of a conventional non-excited operation type electromagnetic brake in a state where braking is manually released.

FIG. 5 is a half vertical sectional side view of a conventional non-excited operation type electromagnetic brake during braking.

[Explanation of symbols]

 10: Fixed part 11: Main body plate 12: Stator 13: Magnet assembly 13a: Permanent magnet 13b: Excitation coil 13c: Yoke 14: Lining 15: Magnetic ring 20: Rotating part 21: Braking rotary shaft 22: Hub 23: Spring 24: Armature

Claims (2)

[Claims] 1. A fixed part and a rotating part having a rotation axis to be braked rotatable with respect to the fixed part, wherein an armature movable in an axial direction is attached to the rotation axis to be braked, and A magnet assembly having a permanent magnet for attracting the armature and an exciting coil for canceling the magnetic flux of the permanent magnet by energization, and disposed on the outer periphery of the magnet assembly between a degaussing position and a non-gaussing position. A non-excited operation type electromagnetic brake in which a magnetic ring movable in the axial direction is provided, and the magnetic ring is set to the demagnetizing position to short-circuit the magnetic path of the permanent magnet to attenuate the attraction force to the armature. The magnetic resistance of the magnetic path of the permanent magnet when the magnetic ring is set to the non-demagnetizing position, before the magnetic ring is set to the degaussing position. Non-excitation type electromagnetic brake, characterized in that set to be larger than the magnetic resistance of the magnetic path of the permanent magnet. 2. A gap formed in a magnetic path of the permanent magnet is set larger than a gap formed in the magnetic path when the magnetic ring is set at the degaussing position. Item 2. A non-excited operation type electromagnetic brake according to item 1.