JPH0613892B2 - Electromagnetic brake - Google Patents

Abstract

PURPOSE:To use the magnetomotive force effectively by making a ball moves toward the outer diameter direction with an armature retreating from a field core in a non-excited state, and moves toward the inner diameter direction with the armature proceeding in an excited state. CONSTITUTION:An armature 8 retreats toward a field core 4 by a spring force of a spring 15 in a non-excited state of an exciting coil 7. And a ball 44 is looked by a flange 36 and presses a plate spring 31 toward the outer diameter direction. Consequently, a brake lining 35 presses against a brake drum 21 and a motor shaft is braked. On the other hand, the armature 8 is absorbed to the field core 4 against the spring force of the spring 15 in the excited state of the exciting coil 7. Therefore, the ball 44 moves toward the inner diameter direction and the said pressing is released. Thus the magnetomotive force can be used effectively. And the brake torque can be adjusted with the gap between a brake lining 35 and the brake drum 21 changed by changing a fixed position of a ball receiving metal fitting 41 with an adjusting screw 52.

Description

The present invention relates to a shoe-type electromagnetic brake used for braking a rotary shaft in machine tools, various industrial machines, and the like.

[Conventional technology]

An electromagnetic brake of this type is disclosed in Japanese Patent Laid-Open No. 61-52430. This is a brake drum arranged coaxially with the field core on the outside of a field core having an exciting coil, and an arcuate armature attached to the outer peripheral surface of the field core. Is supported by a field core and the other end is always urged in the outer radial direction by a spring for braking, so that the other end is movable in the radial direction. And
When the exciting coil is in the non-excited state, the braking lining presses the brake lining on the outer surface of the armature against the brake drum. The pressure contact is released.

[Problems to be solved by the invention]

However, in such a structure, since the armature is attracted to the field core so as to swing about one end as a fulcrum, a gap is formed between the armature and the field core at the fulcrum side portion. Therefore, there is a problem that the magnetic resistance increases in the magnetic circuit formed around the exciting coil, and the magnetomotive force of the exciting coil cannot be effectively used. That is, it is difficult for the magnetic flux to pass through the gap, and the magnetic flux is diverted to increase the average length of the magnetic path.

Further, the thickness of the brake lining determines the gap between the brake lining in the excited state and the brake drum, so that the gap, that is, the brake torque cannot be adjusted even when the brake lining is installed in a machine of a different model.

[Means for solving problems]

The present invention has been made in view of the above circumstances, and provides an electromagnetic brake that can effectively utilize the magnetomotive force of an exciting coil even if it is a shoe type and that can adjust the brake torque. The electromagnetic brake according to the present invention includes an armature that is opposed to a field core and is supported so as to be capable of parallel translation in the axial direction, a brake drum that is disposed outside the armature, and a surface that is arranged along the inner peripheral surface of the brake drum. And a leaf spring having a brake lining, and a ball receiving fitting provided with an inclined groove on the outer peripheral portion of the armature so as to be movable in the axial direction, a fixing means for fixing the ball receiving fitting to the armature, and an inclined groove. A ball is interposed between the blade and the leaf spring.

[Action]

In the present invention, when the exciting coil is in the non-excited state,
Since the armature retracts from the field core and the ball pushes the leaf spring in the outer diameter direction, the brake lining comes into pressure contact with the brake drum.

On the other hand, when the exciting coil is excited, the armature advances and moves in the ball inner diameter direction, so that the pressure contact is released.

Further, when the fixing position of the ball receiving fitting is changed by the fixing means, the gap between the brake lining and the brake drum in the excited state can be adjusted.

〔Example〕

Hereinafter, the configuration and the like will be described in detail with reference to the embodiments shown in the drawings. FIG. 1 is a longitudinal sectional view showing an electromagnetic brake according to the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, and FIG. 3 is a front view. An electromagnetic brake is shown, and for example, it is attached to the motor 2 and is used for braking the motor shaft 3 as the braked shaft.

Reference numeral 4 denotes a circular annular field core made of a magnetic material such as iron, which is attached to the back side of the motor 2 by bolts (not shown) which penetrate through three mounting holes 5 formed at equal intervals on the outer periphery. It is mounted coaxially with the motor shaft 3. An annular groove 6 opened in the axial direction is provided on an end surface of the field core 4 on the side opposite to the motor 2, and an exciting coil 7 wound in an annular shape is mounted in the annular groove 6.
Reference numeral 8 denotes a disk-shaped armature facing the field core 4. As shown in FIG. 4, the armature 8 has a central hole 11 through which the motor shaft 3 passes,
The guide collars 13 press-fitted and fixed in the mounting holes 5 are passed through the three guide holes 12 provided at equal intervals on the outer peripheral portion, so that the guide collars 13 are supported so as to be movable in the axial direction in parallel while the rotation is restricted. There is. Also, this armature 8
Is provided with a compression coil spring 15 for braking in a plurality of recessed portions 14 formed in the outer end surface of the field core 4.
By being loaded in a state of being compressed and deformed between the bottom surface of the armature 8 and the surface of the armature 8, it is constantly urged in a direction away from the field core 4.

Reference numeral 21 denotes a brake drum for braking the motor shaft 3, which has a bottomed cylindrical shape and has a braking surface 21a formed on the inner peripheral surface thereof. The brake drum 21 is arranged coaxially with the armature 8 and the field core 4, and a peripheral wall covers the outside of the armature 8 and the field core 4. A hub 22 is provided at the center of the bottom, and is connected to the motor shaft 3 in the rotation direction via a key (not shown). On the other hand, movement in the axial direction is restricted by the snap ring 23. Note that the regulation in the axial direction may be performed by using a snap ring as well as regulation means utilizing a screw action, for example. Reference numeral 24 is a through hole for inserting the mounting bolt from the outside, and is formed in the bottom portion of the brake drum 21 corresponding to the mounting hole 5.

Reference numeral 31 is a leaf spring attached to the outer peripheral surface of the field core 4, and three leaf springs 31 are arranged along the inner peripheral surface of the brake drum 21 outside the compression coil spring 15 at equal intervals. As shown in the front view and the plan view of FIG. 5 and FIG. 6, the leaf spring 31 is made of a plate material having a substantially trapezoidal shape in plan view, and is formed at both ends of the mounting hole 3 through which the mounting screw 32 penetrates.
And a shoe 3 formed in the center
The shoe holding portion 31b to which 4 is fixed is connected by an arc-shaped connecting portion 31c that can be easily elastically deformed.
That is, even if the fixing portion 31a is fixed to the leaf spring 31,
The shoe holding portion 31b can be elastically deformed in the radial direction by the connecting portion 31c. The shoe 34 is fixed to the outer surface of the shoe holding portion 31b by welding, rivets or the like. Reference numeral 35 is a brake lining fixed on the shoe 34, and reference numeral 36 is a flange formed by bending a pair of notches on the front end both sides of the shoe holding portion 31b to prevent a ball, which will be described later, from coming off. .

Reference numeral 41 denotes a ball receiving fitting, which is formed in a substantially plate shape having a pair of projecting portions 41a on both sides as shown in the front view, the plan view, and the side view in FIGS. 7, 8, and 9. By fitting the protrusion 41a into the notch 42 provided on the outer peripheral surface of the armature 8, the armature 8 is axially movably disposed at a portion corresponding to the inside of the leaf spring 31. Reference numeral 43 denotes an inclined surface formed on the upper surface of the projecting portion 41a, which inclines so as to become deeper as the distance from the field core 4 increases, and a ball locking wall 43a is formed at the tip end portion. An inclined groove is provided on the outer peripheral portion of the armature 8 by the inclined surface 43 and the side surfaces of the notches 42 located on both sides of the inclined surface 43.

Reference numeral 44 denotes six balls interposed between the inclined surface 43 and the leaf spring 31. In this ball 44, the armature 8 to which the ball receiving fitting 41 is screwed is the compression coil spring 1
When pressed by 5, it tries to move in the outer diameter direction while being engaged with the flange 36, so that the leaf spring 31 is always pressed in the outer diameter direction, and the brake lining 35 is brought into pressure contact with the brake drum 21.

Reference numeral 51 is a fixing screw for fixing the ball receiving fitting 41 to the armature 8, and 52 is a pair of adjusting screws for adjusting a gap between the armature 8 and the field core 4. The fixing screw 51 passes through a through hole 53 arranged in the central portion of the ball receiving fitting 41 and is screwed into a screw hole 54 of the armature 8. On the other hand, as shown in the enlarged cross-sectional view of the main part of FIG. 10, the adjusting screw 52 penetrates the screw holes 55 arranged on both sides of the ball receiving fitting 41 and is in contact with the recessed portion 56 of the armature 8. That is, these screws are the ball receiving fittings 4.
A fixing means for fixing 1 to the armature 8 at a predetermined position is constituted. Here, the length under the neck of the adjusting screw 52 is set to be longer than the sum of the thickness of the ball receiving fitting 41 and the depth of the recess 56.

In the electromagnetic brake configured as described above, in the non-excited state where the exciting coil 7 is not excited,
As shown in the enlarged view of the figure, the armature 8 is pressed by the elastic force of the compression coil spring 15 so as to form a gap g between the armature 8 and the attraction surface of the field core 4 and retracts with respect to the field core 4. At this time, since the ball 44 is locked by the flange 36, it moves on the inclined surface 43 toward the field core 4 side and presses the leaf spring 31 in the outer diameter direction. For this reason, the brake lining 35 is pressed against the brake drum 21, and the rotation of the brake drum 21 is blocked by the frictional force with the brake lining 35.
Is braked.

On the other hand, in the excited state in which a voltage is applied to the exciting coil 7, as shown in FIG. 12, a magnetic flux Φ is generated, and the armature 8 is attracted to the field core 4 against the repulsive force of the compression coil spring 15. To be done. Therefore, the armature 8 advances and the ball 44 moves in the inner diameter direction, so that the pressure contact is released. That is, a gap s is formed between the brake drum 21 and the brake lining 35. At this time, the ball 44 is locked by the ball locking wall 43a.

Therefore, by moving the entire armature 8 forward and backward, it is possible to bring the brake drum 21 into the braking and open state, so that the armature 8 can be brought into close contact with the field core 4 when released. As a result, it is possible to prevent the formation of voids in the magnetic circuit formed around the exciting coil 7 and reduce the magnetic resistance, so that the magnetomotive force can be effectively utilized.

Further, when the fixing screw 51 is loosened during excitation and the adjusting screw 52 is rotated in the tightening direction, the gap g ₁ between the head of the fixing screw 51 and the ball receiving metal fitting 41 becomes small as shown in FIG. Gap between 41 and armature 8
₂ increases. At this time, the gap s shown in FIG. 12 becomes smaller, and the gap g between the armature 8 and the field core 4 at the time of non-excitation becomes smaller at an arbitrary ratio to the gap s depending on the angle of the inclined surface 43. Therefore, since the gap s can be adjusted within the allowable range of the gap g, when assembling the electromagnetic brake 1 into a machine of a different model, the braking torque can be adjusted by how to tighten the adjusting screw 52. In other words, in other words, if the gap g is adjusted, the gap s is naturally determined in terms of design. Therefore, the gap s can be adjusted before the brake drum 21 is connected to the motor shaft 3. Therefore, it is not necessary to specially form a through hole for adjusting the clearance in the brake drum 21.

FIG. 13 is a vertical sectional view showing another embodiment, and FIG. 14 is a first sectional view.
FIG. 3 is a sectional view taken along line XIV-XIV in FIG.
Members which are the same as or equivalent to those shown in the drawings and FIG. 2 are assigned the same reference numerals and explanations thereof are omitted. In this embodiment, the notch 42 of the armature 8 is provided with an inclined surface 61, and an adjusting ball 62 is interposed between the inclined surface 61 and the ball receiving fitting 41. Then, the adjusting screw 52 screwed into the ball receiving fitting 41 is in contact with the adjusting ball 62.

Therefore, in such an embodiment, when the adjusting screw 52 is screwed in the excited state, the ball receiving fitting 41 is moved in the radial direction, and this movement is adjusted so that the gap s between the brake lining 35 and the brake drum 21 becomes smaller. It If this state is changed to the non-excitation state, the gap g between the armature 8 and the field core 4 becomes smaller.
Here, the value of the gap g when the gap s is determined is
3 angle, the diameters of the balls 44 and 62, the screw pitch of the adjusting screw 52, and the like.

It should be noted that in the above-described embodiment, two balls 44 are used for each three
Although the example in which the sets are arranged at equal intervals has been described, the present invention is not limited to this, and it is possible to appropriately change the positions by arranging the balls 44 one by one. Further, the ball receiving fitting 41 provided with the relatively low ball locking wall 43a has been described, but the height of the ball locking wall 43a can be appropriately changed.

〔The invention's effect〕

As described above, according to the present invention, the armature, which is opposed to the field core and is supported so as to be movable in parallel in the axial direction, the brake drum disposed outside the armature, and the inner peripheral surface of the brake drum are provided. And a leaf spring having a brake lining arranged on the surface thereof, a ball receiving metal fitting having an inclined groove on the outer peripheral portion of the armature is movably provided in the axial direction, and a fixing means for fixing the ball receiving metal fitting to the armature is provided. Since the ball is interposed between the inclined groove and the leaf spring, the ball moves in the outer diameter direction when the armature retracts from the field core, and moves in the inner diameter direction when the armature advances.

Therefore, even with the shoe type, it is possible to bring the brake drum into the braking and released state by advancing and retracting the entire armature, and the armature can be brought into close contact with the field core when released. as a result,
Since the resistance of the magnetic circuit formed around the exciting coil can be reduced, the magnetomotive force can be effectively used.

Further, since the gap between the brake lining and the brake drum can be adjusted by changing the fixing position of the ball receiving fitting by the fixing means, the brake torque can be adjusted.
Furthermore, when incorporating this electromagnetic brake into machines of different models, the brake torque can be adjusted by changing the angle of the inclined groove provided on the outer peripheral portion of the armature.

[Brief description of drawings]

1 is a longitudinal sectional view showing an electromagnetic brake according to the present invention, FIG. 2 is a sectional view taken along line II-II of FIG. 1, FIG. 3 is a front view, and FIG.
The drawings are front views showing an armature, FIGS. 5 and 6 are front views and plan views of a leaf spring, and FIGS. 7 to 9 are front views, plan views, side views, and FIG. 10 showing ball receiving fittings. 11 is an enlarged cross-sectional view of a main part, FIG. 11 is an enlarged cross-sectional view of a main part in a non-excited state, FIG. 12 is an enlarged cross-sectional view of a main part in an excited state, and FIG. 13 is a main part showing another embodiment. Sectional view, first
FIG. 4 is a sectional view taken along line XIV-XIV in FIG. 4 …… Field core, 8 …… Armature, 21 ……
Brake drum, 31 ... Leaf spring, 35 ... Brake lining, 41 ... Ball receiving fitting, 42 ... Notch,
43: inclined surface, 44: ball, 42: adjusting screw.

Claims (1)

[Claims] 1. A field core having an exciting coil, an armature facing the field core, movably supported in parallel with the axial direction and urged in a direction away from the field core by a control spring, and the armature and the armature. A brake drum which is arranged coaxially with the field core and covers the outside of these members, and a leaf spring which is arranged along the inner peripheral surface of the brake drum and is attached to the field core so as to be elastically deformable in the radial direction, A brake lining provided on the outer surface of the leaf spring is provided, and a ball receiving fitting provided with an inclined groove that becomes deeper as the distance from the field core is increased in an axial direction in a portion corresponding to the inside of the leaf spring of the armature. And a fixing means for fixing the ball receiving fitting to the armature, and Electromagnetic brake, characterized in that interposed a ball to press the leaf spring to always outer diameter direction between the spring.