JP2000179583A - Ac electromagnetic brake or ac electromagnetic clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly operate a brake or a clutch even by excitation of AC, by providing an armature displaced to a yoke side by magnetic flux generated by carrying a current in a coil. SOLUTION: A fixed part is provided with an armature 13 arranged movably along a direction of an axial line L relating to a yoke 12 housing a coil 11 and a compression spring interposed between the yoke 12 and the armature 13. In the case that carrying of a current in the coil 11 is cut off, the armature 13 is pressed to a disk by energizing force of the spring, and brake force is applied to rotation. The coil 11 is excited by a power source AC. The yoke 12 and the armature 13 are formed by laminating many silicon steel plates vertical to the axial line L. At least the yoke 12 is thus formed in a layered structure, so that a brake and a clutch can be properly operated by AC excitation by small suppressing an iron loss and eddy current loss in a magnetic circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC electromagnetic brake used for braking a motor or an AC electromagnetic clutch for transmitting and disconnecting a driving force between a motor and a driven shaft.

[0002]

2. Description of the Related Art Conventional electromagnetic brakes or clutches are disclosed, for example, in JP-A-59-98135 and JP-A-8-98135.
What is described in 247181 gazette etc. is known. The electromagnetic brakes and the like disclosed in these publications are all DC excitation types. For example, when an electromagnetic brake is used for braking an AC motor, an AC power supply for the motor is rectified by a rectifier, or a DC power supply is separately provided. It must be prepared and supplied to the electromagnetic brake.

[0003]

However, in the above-described conventional DC-excited electromagnetic brake or clutch,
When used in combination with a motor, a rectifier or a dedicated DC power source is required, and thus there is a problem that an electric circuit becomes complicated. Therefore, a method of exciting by alternating current is conceivable.However, if the conventional configuration for direct current excitation is used as it is, iron loss and eddy current loss in the magnetic circuit due to the alternating magnetic flux increase, and these losses are usually caused by the coil. Is much larger than the resistance loss, the heat is excessively generated and normal operation cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and has as its object to provide an AC electromagnetic brake or an AC electromagnetic clutch which operates properly even with AC excitation.

[0005]

In order to achieve the above object, an AC electromagnetic brake or AC electromagnetic clutch according to the present invention is formed by laminating a coil to be AC-excited and a steel plate, and is disposed around the coil. A yoke that transmits the magnetic flux generated by the coil and an armature that is provided movably in the axial direction with respect to the yoke and that is displaced toward the yoke by a magnetic flux generated by energizing the coil.

According to the above configuration, iron loss and eddy current loss in the magnetic circuit can be reduced, and the brake and clutch can be normally operated by AC excitation. As for the armature, a steel plate having no laminated structure may be used, or a laminated steel plate may be used.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an AC electromagnetic brake or an AC electromagnetic clutch according to the present invention will be described.

First Embodiment: FIGS. 1 and 2 show a first embodiment.
1 shows the structure of a non-excited operation type dry double-plate electromagnetic brake according to an embodiment of the present invention. FIG. 1 is an explanatory view showing a laminated structure of steel sheets having characteristic features, and FIG. First, the overall structure will be described with reference to FIG.

The AC electromagnetic brake according to the first embodiment comprises a fixed portion 10 and a rotating portion 20 rotatable with respect to the fixed portion 10. The fixing portion 10 is provided with a coil 11, a yoke 12 containing the coil 11, an armature 13 movably arranged with respect to the yoke 12 along the direction of the axis L, and interposed between the yoke 12 and the armature 13. The compression spring 14 is provided. Rotating part 20
Has a cylindrical hub 21 to which a not-illustrated rotating shaft is inserted and fixed, and a plate 22 and a disk 23 are fixed to the outer periphery of the hub 21 so as to rotate integrally. A cylindrical cover 15 that covers the armature 13, the plate 22, and the disk 23 from outside is attached to the outer periphery of the yoke 12.

The coil 11 is excited by an AC power supply AC as shown in FIG. Yoke 12 and armature 1
3 is formed by laminating a number of silicon steel plates perpendicular to the axis L, as indicated by vertical lines in the figure. By thus forming at least the yoke 12 in a laminated structure, iron loss and eddy current loss in the magnetic circuit can be reduced, and the electromagnetic brake can be operated properly.

When the power supply to the coil 11 is cut off, the armature 13 is pressed against the disk 23 by the urging force of the spring, as shown by the solid line in FIG.
A braking force is applied to the rotation of the rotating unit 20 by the frictional force generated between the armature 13 and the disk 23. On the other hand, when the coil 11 is energized, the armature 13 is drawn toward the yoke 12 and displaced by the generated electromagnetic force as shown by a two-dot chain line against the urging force of the spring 14, and the armature 13 is displaced. A gap is created between the disk 23 and the braking is released.

FIGS. 3A to 3C are explanatory views similar to FIG. 1 showing a modification of the first embodiment. Among them, FIG. 3A shows that only the yoke 12 has a laminated structure of a silicon steel plate,
An example in which the armature 13 is formed of pure iron is shown. In the example of FIG. 3B, the yoke 12 and the armature 1
3 is formed by laminating a number of silicon steel plates parallel to the axis L as indicated by horizontal lines in the figure. Further, in the example of FIG. 3 (C), a portion 12a of the yoke 12 facing the armature 13 is formed by laminating a number of silicon steel plates parallel to the axis L as shown by horizontal lines in the drawing. Forming
The portion 12b opposite to the armature 13 and the armature 13 are formed by laminating a number of silicon steel plates perpendicular to the axis L as indicated by vertical lines in the drawing. The combination of the yoke 12 and the armature 13 is optional. Further, in the example of FIG. 3C, the portion 12b may be made of pure iron having no laminated structure.

In any of the configurations, the presence of the laminated steel sheet makes it possible to suppress the loss due to the AC excitation of the coil to a low level and to operate the electromagnetic brake properly. Further, as the characteristics of the AC excitation, the operation speed can be increased because the time constant of the excitation current is small, and the release time is short because the influence of the residual magnetism is small.

Second Embodiment FIGS. 4 and 5 show a second embodiment.
FIG. 4 is a cross-sectional view showing the overall structure of the dry-type AC electromagnetic clutch according to the embodiment, and FIG. 5 is an explanatory view showing a laminated structure of steel plates of a characteristic portion. First, the overall structure will be described with reference to FIG.

The AC electromagnetic clutch according to the second embodiment has
The rotating shaft 30 includes a yoke 40 fixed to a fixed portion (not shown) for rotatably supporting the rotating shaft 30, a rotor 31 fixed to the rotating shaft 30, and a hub 32 rotatably attached to the rotating shaft 30. I have. The yoke 40 includes a cylindrical inner pole wall 41 surrounding the rotating shaft 10, a cylindrical outer pole wall 42 opposed to the inner pole wall 41 at a predetermined interval, an inner pole wall and an outer pole wall. And a disc wall 43 formed perpendicular to the axis.

An electromagnetic coil 50 wound around a bobbin 60 is inserted into a space formed between the inner pole wall 41 and the outer pole wall 42 of the yoke 40. The hub 32 rotatable around the rotation shaft 30 is a resin member having a gear formed around the hub 32, and is rotated by a driving force from an electric motor (not shown). An armature 70 facing the rotor 31 is fixed to the hub 32 via a leaf spring 80 for return so as to be displaceable in the axial direction.

As shown in FIG. 5, in this example, the yoke 4
0 disk wall 43, rotor 31, and armature 70
However, as shown by a vertical line in the figure, a large number of silicon steel plates perpendicular to the rotation axis 30 are stacked. On the other hand, the yoke 40
The inner pole wall 41 and the outer pole wall 42 are formed by laminating a number of silicon steel plates parallel to the rotating shaft 30 as shown by horizontal lines in the drawing.

In the above configuration, when an alternating current is applied to the coil 50, the armature 70 is magnetically attracted to the rotor 31, and the rotation of the hub 32 is transmitted to the rotating shaft 10. When the energization is cut off, the magnetic attraction force disappears, the armature 70 returns to the initial position away from the rotor 31 by the force of the leaf spring 80, and the transmission of the driving force from the hub 32 to the rotary shaft 30 is cut off.

In each of the above-described embodiments, the present invention has been described only with respect to an example in which the present invention is applied to a non-excited operation type dry double-plate AC electromagnetic brake or AC electromagnetic clutch. However, the present invention is also applicable to an AC electromagnetic brake or an AC electromagnetic clutch having another structure to which the present invention can be applied.

[0020]

The AC electromagnetic brake or AC electromagnetic clutch of the present invention has the following excellent effects because it is constructed as described above. (1) Iron loss and eddy current loss in the magnetic circuit can be reduced, and the brake and clutch can be operated properly by AC excitation.

(2) Therefore, for example, when the AC electromagnetic brake of the present invention is applied to an AC motor, there is no need to provide a rectifier or a separate DC power supply as in the prior art, and the configuration of the electric circuit can be simplified. .

(3) Since the time constant of the exciting current is small, the operating speed can be increased, and the release time can be shortened because the influence of the residual magnetism is small. Alternatively, a clutch can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a laminated structure of steel plates as a characteristic part of a non-excited operation type dry double-plate electromagnetic brake according to a first embodiment of the present invention.

FIG. 2 is a half sectional view showing the entire structure of the electromagnetic brake shown in FIG.

FIG. 3 is an explanatory diagram similar to FIG. 1, illustrating a modification of the first embodiment.

FIG. 4 is a cross-sectional view illustrating an entire configuration of a dry-type electromagnetic clutch according to a second embodiment of the present invention.

FIG. 5 is an explanatory view showing a laminated configuration of steel plates of a characteristic portion of the clutch shown in FIG. 4;

[Explanation of symbols]

 11: Coil 12: Yoke 13: Armature

Claims (3)

[Claims] An AC-excited coil, a yoke formed by laminating steel plates, disposed around the coil and transmitting a magnetic flux generated by the coil, and movable in the axial direction with respect to the yoke. An AC electromagnetic brake or an AC electromagnetic clutch, the armature being displaced toward the yoke by a magnetic flux generated by energizing the coil. 2. The AC electromagnetic brake or AC electromagnetic clutch according to claim 1, wherein the armature is formed by stacking steel plates. 3. The AC electromagnetic brake or AC electromagnetic clutch according to claim 1, wherein the armature is formed of non-laminated pure iron.