JP2546637Y2 - Electromagnetic brake - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic brake in which an armature is moved forward and backward by a spring force of a braking spring and a magnetic attraction force of an electromagnetic coil to brake rotation and release braking.

[0002]

2. Description of the Related Art As one kind of such an electromagnetic brake,
For example, as disclosed in JP-A-63-115920, there is known an electromagnetic brake in which a brake shoe is provided and a rolling element such as a ball or a roller is interposed between the brake shoe and an armature. . This electromagnetic brake is provided with a field core fixed to a fixed portion such as a motor and having an electromagnetic coil provided therein, and an armature capable of moving back and forth in the axial direction with a plane facing a magnetic pole surface of the field core. The armature is urged in a direction away from the field core by a braking spring mounted in a recess of the field core.

When the electromagnetic coil is not excited,
A predetermined gap is formed between the magnetic pole surface of the field core and the plane of the armature by the spring force of the braking spring, and when the electromagnetic coil is excited, the armature resists the magnetic force of the field core against the spring force of the braking spring. It is configured to be magnetically attracted to the surface.

Further, a brake drum as a member to be braked, which is formed in a dish shape, is key-fixed to a rotating shaft of the motor which penetrates through the inner hole of the field core and the inner hole of the armature. The cylindrical portion covers the outer peripheral surface of the field core and the armature via a space. In the space, a plurality of arc-shaped brake shoes are held by arc-shaped leaf springs having both ends fixed to the outer peripheral surface of the field core, and the outer peripheral surface is fixed to each of the brake shoes. An arcuate lining facing the inner peripheral surface of the brake drum is housed.

Further, a plurality of balls are interposed between a tapered surface formed on the outer peripheral surface of the armature and a bent piece of a leaf spring bent substantially in parallel with the tapered surface. ing.

[0006] With this configuration, when the electromagnetic coil is not excited, the armature is separated from the magnetic pole surface of the field core by the spring force of the braking spring, and at this time, the ball moves on the tapered surface of the armature. Since the brake shoe is pressed against the inner peripheral surface of the cylindrical portion of the brake drum against the spring force of the leaf spring by the action, the rotation of the rotating shaft is braked via the brake drum.

When the electromagnetic coil is excited from this state to generate magnetic flux, the armature is attracted to the magnetic pole surface of the field core against the spring force of the braking spring, and the ball is released from being held by the inclined surface of the leaf spring. As a result, the diameter of the spring is reduced by the elastic return of the plate spring, the pressure contact of the brake shoe against the inner peripheral surface of the cylindrical portion of the brake drum is released, and the rotation shaft integrated with the brake drum can rotate.

[0008]

However, in the conventional electromagnetic brake configured as described above, since the rolling elements move along the tapered surface of the armature during braking, the rolling elements are inclined, in other words. If the armature moves in the radial direction while moving in the moving direction,
The arcuate leaf spring or brake shoe is pushed in the direction of movement of the armature by the spring force of the brake spring.

For this reason, there arises a problem that the leaf spring is twisted or a spring force of the braking spring is applied to the rotating shaft via the brake shoe and the brake drum. In order to solve such problems and increase the durability of the device, the rigidity of the brake shoe supporting leaf spring may be increased. However,
In such a case, the spring force of the brake spring and the magnetic attraction force of the electromagnetic coil must be set large, and the device cannot be provided at a large size and at low cost.

This invention prevents the torsion of the leaf spring during braking and the spring force of the braking spring acting on the rotating shaft, and ensures the durability of the leaf spring and the reliability of quality for manufacturers of motors and the like to which the electromagnetic brake is mounted. The purpose is to increase. Also, by simplifying the shape of the leaf spring and the shape of the armature,
An object is to provide an electromagnetic brake at low cost.

[0011]

According to the present invention, in order to achieve the above object, a field core having an electromagnetic coil provided therein and a braking spring which is supported opposite to the field core so as to be able to advance and retreat in the axial direction and is always provided. An armature biased in a direction away from the field core, a member to be braked having a cylindrical portion disposed coaxially with the armature and the field core, and an outer peripheral surface or an inner peripheral surface of the cylindrical portion of the member to be braked. A plurality of brake shoes are arranged and individually supported elastically on the field core by leaf springs. Tapered surfaces are provided at respective portions of the armature radially opposed to the brake shoes, and the tapered surface and the brake are provided. In an electromagnetic brake with rolling elements interposed between the shoe and the shoe, the brake shoe A shape and a second pressure receiving portion for receiving a first pressure receiving portion for receiving a force and axial force component, the first pressure receiving portion by bending an end portion of the leaf spring and superimposed on the second pressure receiving portion,
It is characterized in that these members are integrally fixed.

Further, in such an electromagnetic brake, it is necessary to prevent the rolling elements from shifting in the circumferential direction.
Without machining the guide grooves for rolling elements on the armature,
By forming the rolling element guide piece integrally with the leaf spring,
The device can be provided at lower cost.

[0013]

When the electromagnetic coil is not energized, the armature is separated from the magnetic pole surface of the field core by the spring force of the braking spring, and at this time, the rolling element uses the taper surface provided on the armature to apply the brake shoe to the leaf spring. The rotation of the rotating shaft is braked through these members because the cylinder is pressed against the cylinder portion against the force. Further, when the electromagnetic coil is excited from this state to generate magnetic flux, the armature is attracted to the magnetic pole surface of the field core against the spring force of the braking spring, and the rolling element is released from the tapered surface of the armature. The spring is elastically restored, the pressure contact of the brake shoe against the cylindrical portion of the member to be braked is released, and the rotation shaft integrated with the member to be braked can rotate.

[0014]

1 to 4 show an embodiment of the electromagnetic brake according to the present invention. FIG. 1 is a front view of the electromagnetic brake, FIG. 2 is a sectional view of the electromagnetic brake, and FIG. FIG. 4 is a front view of the brake shoe assembly. Hereinafter, a detailed description will be given based on these drawings.

The electromagnetic brake 1 is mounted on a motor 2 which is a driving source of an industrial robot, and a field core 4 having an electromagnetic coil 3 provided therein is fixed to a bracket of the motor 2 by screws. The field core 4 is a clapper-type electromagnet, and is formed in an annular groove 4a in which the electromagnetic coil 3 is insulated and fixed by resin with an opening in the axial direction, and a cylindrical outer pole portion serving as an outer peripheral wall of the annular groove 4a. Spring hole 4b,
A hole (not shown) for press-fitting and fixing a spring pin is formed in a magnetic pole surface of the outer pole portion. The spring holes 4b and the spring pin press-fitting and fixing holes are individually formed at positions that divide the circumferential direction of the field core 4 into three equal parts with different phases.

In such a field core 4, a disk-shaped armature 5 is supported by being prevented from rotating by a spring pin (not shown) so that a predetermined gap is formed when the electromagnetic coil 3 is not excited. Have been. The armature 5 is driven by the spring force of the brake spring 6 loaded in the spring hole 4 b of the field core 4 and the magnetic attraction force of the electromagnetic coil 3.
It is movable in the axial direction opposite to the magnetic pole surface of the field core 4.

The armature 5 is formed with a concave groove 5a in which a rolling element 9 to be described later is mounted at a position dividing the outer circumference into three equal parts, and the bottom of the concave groove 5a becomes deeper as the distance from the field core 4 increases. And

A brake shoe 7 is disposed radially outside the tapered surface 5 b of the armature 5, and each brake shoe 7 is elastically supported on the field core 4 by a leaf spring 8. The brake shoe 7 includes a rolling element 9 described later.
Of the spring force of the braking spring 6 acting through the first pressure receiving portion 7a that receives a radial component force and the second pressure receiving portion 7b that receives an axial component force.

The plate spring 8 disposed in the axial direction has a shape in which one end in the longitudinal direction of a rectangular plate member is bent inward, and one end thereof is connected to the first pressure receiving portion 7a and the second pressure receiving portion 7b of the brake shoe 7. And are integrally fixed by welding or rivets. The base of the leaf spring 8 superimposed on the brake shoe 7 is fixed to the field core 4 with screws or the like. A cylindrical roller 9 as a rolling element is individually interposed in a space formed by the end of the leaf spring 8 fixed to the brake shoe 7 and the tapered surface 5b of the armature 5. The lining 10 fixed to the brake shoe 7 has a structure in which the lining 10 comes into contact with and separates from the inner peripheral surface of the cylindrical portion of the brake drum 11 as a member to be braked, which is mounted on the rotating shaft 2 a of the motor 2.

The electromagnetic brake 1 having the above structure
In the non-excited state in which the electromagnetic coil 3 is not energized as shown in FIG. 2, the armature 5 is separated from the magnetic pole surface of the field core 4 by the spring force of the braking spring 6, and the roller 9 is tapered by the tapered surface of the armature 5. 5b, the brake shoe 7 is pressed against the cylindrical portion of the brake drum 11 against the spring force of the leaf spring 8, so that the rotation of the rotary shaft 2a is braked via the brake shoe 7. Further, when the electromagnetic coil 3 is excited from this state to generate a magnetic flux, the armature 5 is attracted to the magnetic pole surface of the field core 4 against the spring force of the braking spring 6, and the roller 9 is moved to the tapered surface 5 of the armature 5.
As a result, the leaf spring 8 is elastically restored, the pressure contact of the brake shoe 7 against the cylindrical portion of the brake drum 11 is released, and the rotary shaft 2a integral with the brake drum 11 becomes rotatable.

Next, an electromagnetic brake according to another embodiment of the present invention will be described with reference to FIGS. 5 and 6. FIG. FIG.
Is a side view of the brake shoe assembly, and FIG. 6 is a front view in which a part of the brake shoe assembly is broken. The brake shoe assembly 12 shown in these drawings has been developed in order to simplify the shape of the armature and provide the device at a lower cost.

That is, a pair of guide pieces 13a for limiting the circumferential movement of the roller 9 is formed in the leaf spring 13, and the outer peripheral surface of the armature 5 in FIG. Guide groove 5 as tapered surface
a, the machining can be reduced. In the above description, the external expansion type electromagnetic brake has been described as an embodiment, but the present invention is also applied to an internal tightening type electromagnetic brake incorporating a brake wheel as a member to be braked.

[0023]

As described above, according to the present invention, in the electromagnetic brake having the rolling element interposed therebetween, the brake shoe is connected to the first pressure receiving portion which receives the radial component of the spring force of the braking spring and the axial component. The second pressure receiving portion has a shape formed by receiving the second pressure receiving portion, and the end portion of the leaf spring is bent so as to overlap with the first pressure receiving portion and the second pressure receiving portion so as to be integrally fixed. The labor can be reduced, and the electromagnetic brake can be provided at low cost.

Further, since the leaf spring is disposed in the axial direction of the apparatus, the torsion in the axial direction of the leaf spring and the spring force of the braking spring acting on the rotating shaft during braking are prevented, and the quality of the motor and other manufacturers is reduced. Reliability can be improved. Furthermore, since the guide piece is integrally formed with the leaf spring to simplify the shape of the armature, machining of the armature is reduced, and the electromagnetic brake can be provided at a lower cost.

[Brief description of the drawings]

FIG. 1 is a front view of an electromagnetic brake according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the electromagnetic brake of FIG.

FIG. 3 is a side view of a brake shoe assembly.

FIG. 4 is a front view of the brake shoe assembly.

FIG. 5 is a side view of the brake shoe assembly.

FIG. 6 is a front view in which a part of the brake shoe assembly is broken.

[Explanation of symbols]

 3 electromagnetic coil 4 field core 5 armature 6 brake spring 7 brake shoe 8 leaf spring 9 roller

Claims (2)

(57) [Scope of request for utility model registration] 1. An armature having an electromagnetic coil provided therein, an armature opposed to the field core and supported in the axial direction so as to be able to advance and retreat in an axial direction, and constantly urged by a braking spring in a direction away from the field core. A member to be braked having a cylindrical portion disposed coaxially with the core, and a plurality of members to be braked arranged along the outer peripheral surface or inner peripheral surface of the cylindrical portion of the member to be braked and individually elastically supported by the field core by leaf springs. An electromagnetic brake having a brake shoe, and a tapered surface provided at each portion of the armature radially opposed to the brake shoe, and a rolling element interposed between the tapered surface and the brake shoe. A first pressure receiving portion receiving a radial component of the spring force of the brake spring and a second pressure receiving an axial component of the shoe. The electromagnetic brake is characterized in that the plate spring has a shape comprising a plurality of parts, and an end of the leaf spring is bent to overlap the first pressure receiving part and the second pressure receiving part, and these members are integrally fixed. 2. The electromagnetic brake according to claim 1, wherein the leaf spring is formed with a pair of guide pieces for restricting a circumferential movement of the rolling element.