JPS5821029A - Electromagnetic brake - Google Patents

Abstract

PURPOSE:To improve an effect of heat radiation, in an electromagnetic brake filled with a magnetic pulverulent body in an annular gap between a field core and external cylindrical member, by both obtaining fine brake power and facilitating maintenance work, that is, by providing a magnetic resistance adjusting pipe in an axially displaceable state to the periphery of the external cylindrical member. CONSTITUTION:When a magnetic resistance adjusting pipe 24 is placed in a position, as shown by a full line in the drawing, a peripheral wall part 18A of an external cylindrical member 18, not appearing with the adjusting pipe 24, is provided with large magnetic resistance, and magnetic force of integrally magnetizing a magnetic pulverulent body 21 is decreased, then rotary motion of a peripheral wall part 20A of a cylinder unit 20 is locked by small brake power. If the adjusting pipe 24 is moved to a position of a virtual line, the magnetic resistance is reduced. In this case, magnetic flux passes through a field core 16, the peripheral wall part 20A of the cylinder unit 20 of the cylinder unit 20 and the pulverulent body 21 in a gap S and the peripheral wall part 18A of the external cylindrical member 18, increased with the sectional area, and magnetically biding force of the pulverulent body is increased maximum to strongly brake the cylinder unit 20, tending to rotate, with almost infinite resistance. Further a brake mechanism of the magnetic pulverulent body is provided externally of the field core, and a brake is excellent with heat radiation quality while can be easily performed with replacement and supply of the magnetic pulverulent body.

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the peripheral wall of a cylindrical body that rotates together with a rotating shaft is inserted into an annular gap filled with magnetic powder particles, and by magnetizing the magnetic powder particles, the cylindrical body This invention relates to an electromagnetic brake that uses so-called magnetic powder to brake the rotary shaft and absorb the kinetic energy of the rotating shaft.

As shown in the side view of the upper half of the conventional electromagnetic brake in FIG. A fixing member 4 is provided inside the cylinder 2, which is arranged concentrically inside the cylinder 2, and whose outer circumferential surface faces the inner circumferential surface of the cylinder 2 toward the circumferential wall 2.

Both the cylinder 2 and the fixing member 4 are made of magnetic material,
So that the magnetic flux Φ generated when voltage is applied to the electromagnetic coil 5 built into the field core 3 also passes through the fixed member 4.
A longitudinally intermediate portion of the peripheral wall portion 2A of the cylinder 2 is formed of a non-magnetic material 6.

The field core 3 has its front and rear openings closed by flanges 8 and 9 which are fixed by a group of bolts 7, and the boss portion 8A of the flange 8 through which the rotating shaft 1 is inserted has a bearing 10 that supports the rotating shaft.゜10 is incorporated.

On the other hand, the boss portion 4A of the fixing member 4 is fixed to the 7 flange 9 with a plurality of bolts 11.

Magnetic powder particles 12 are loaded inside the cylinder 2, and a seal 13 is provided at the contact portion between the cylinder 2 and the boss portion 4A of the fixing member 4.
to prevent it from leaking outside.

A conventional electromagnetic brake with such a structure has terminal 1
When a voltage is applied to the electromagnetic coil 5 through an external conductor (not shown) connected through the cylinder 4, a magnetic flux Φ is generated along the path shown by the broken line in the figure, and the cylinder ? The magnetic powder grains 12 inside are excited.

The excited magnetic powder particles 12 1 are magnetically attracted to the image and combined into a single body, becoming solid and connecting the cylinder 2 and the fixing member 4.

In this case, the coupling force is proportional to the magnetic flux Φ, and the magnetic powder particles 12 that are integrally coupled provide infinite resistance to the cylinder 2. is converted into thermal energy.

Although the rotating shaft 1 is braked in this way, this type of electromagnetic brake lacks heat dissipation because the field core 3 containing the electromagnetic coil 5 exists outside the cylinder 2 where a large amount of heat is generated. There were some difficulties.

In addition, since the magnetic powder particles 12 are loaded into the cylinder 2, which is located inside the annular field core and has a sealed structure, each time the magnetic powder particles 12 are replaced or replenished,
The whole thing has to be disassembled, and even if it were to be assembled and manufactured anew, disassembly also requires extra time and effort.

In particular, the braking force is adjusted by adjusting the magnetomotive force, that is, by controlling the current, so it is difficult to adjust the braking force with minute force, and the adjustment requires an extra member to control the current. There are other difficulties.

Based on the above-mentioned viewpoints, the present invention provides an electromagnetic brake that has a high heat dissipation effect, is simple in structure and maintenance, and is particularly capable of finely adjusting the braking force. An annular field core having a groove and having a middle part in the axial direction of the outer wall of the annular groove as a magnetism blocking part made of a non-magnetic material, and on the outside of the field core,
The peripheral wall is inserted into the annular gap between the outer cylindrical body, the field core, and the outer cylindrical body, and is integrated with the rotating shaft. It comprises a rotating cylindrical body, a required amount of magnetic powder particles to be charged into the gap, and a magnetic resistance adjusting tube whose inner circumferential surface is fitted closely to the outer circumferential surface of the outer cylindrical body so as to be movable in the axial direction. The feature is that the braking force is adjusted by displacing the magnetic resistance adjusting tube in the axial direction.

Next, the electromagnetic brake of the present invention will be described by way of embodiments with reference to the drawings.

FIG. 2 shows an embodiment of the electromagnetic brake of the present invention in a longitudinal sectional side view. As shown in the drawings, the electromagnetic brake of the present invention has an annular field core 16 provided with an annular groove 16A for accommodating an electromagnetic coil 15 fixed to a mounting plate 17, and an outer cylindrical body on the outside of this field core. 18 are arranged concentrically.

An annular gap S is formed between the peripheral wall portion 18A of the outer cylinder 18 and the outer wall 16]3 of the annular groove 16A of the field core 16.

Into the gap S, a circumferential wall portion 2OA of a cylindrical body 20 whose center portion is welded to an end portion 19A of the rotating shaft 19 is inserted, and magnetic powder particles 21 are also inserted.

A large number of holes 22 are bored in the peripheral wall 2OA of the cylindrical body 20, and the magnetic powder particles 21 are also present in these many holes 22.

On the other hand, an intermediate portion in the axial direction of the outer wall 16B of the field core 16 is formed with a magnetic demagnetizing portion 23 made of a non-magnetic material (for example, copper or stainless steel), and the outer cylindrical body 18 has a peripheral wall portion. The thickness of the 18A is made thinner to increase the magnetic resistance.

Furthermore, a magnetic resistance adjustment tube 24 whose inner peripheral surface is in close contact with the outer peripheral surface of the outer cylinder 18 is fitted onto the outside of the outer cylinder 18 so as to be movable in the axial direction.

The magnetic resistance adjusting tube 24 has a function of partially increasing the wall thickness of the outer cylinder 18 to reduce the magnetic resistance.
When 4a is in a position where it does not extend from the end 23A of the magnetism-interrupting portion 23 to the base 9 of the field core 16 on the outer wall 16B of the field core 16, that is, in the position shown by the solid line in the figure, the voltage is applied to the electromagnetic coil 15. Even if the voltage is applied, the peripheral wall portion 8 of the outer cylindrical body 18 that does not face the magnetic resistance adjustment tube 24
The magnetic resistance at the base part of A is large, and the magnetic powder particles 12
It acts so that the magnetic force that magnetically couples the two is minimized.

The rotating shaft 19 is supported by bearings 25A and 25B relative to the field core 16, and a seal 26 is installed between the field core 16 and the boss portion 20B of the cylindrical body 20 welded to the rotating shaft 19. In order to prevent the magnetic powder particles 21 from flowing into the bearings 25A and 25B, a magnetic powder supply/discharge port 2'7 is provided on the outer cylinder body. The lid piece was closed in 2 days. Furthermore, a non-magnetic ring member 29 is interposed between the base of the field core 16 and the base of the outer cylinder 18.

The electromagnetic brake of the present invention having the above-described structure operates with the minimum braking force by placing the magnetic resistance adjustment tube 24 in the position shown by the solid line in FIG. When the magnetic resistance adjustment tube 24 is moved to this position, the braking force is maximized.

That is, when the magnetic resistance adjustment tube 24 is in the position shown by the solid line, the magnetic resistance of the peripheral wall 18A of the outer cylinder 18, which the magnetic resistance adjustment tube 24 does not face, is large, and the magnetic powder particles 21 are magnetized and integrated. Since the magnetic force is small, the peripheral wall portion 20. of the cylindrical body 20. The braking force that restrains the rotation of A is small.

Next, the wall thickness of the peripheral wall portion 18A increases by the thickness of the magnetic force 24, and the magnetic resistance adjusting tube 24 is moved from the position shown by the solid line in FIG. 2 to the position shown by the imaginary line, and the magnetic The cross-sectional area through which the magnet passes increases, and the magnetic resistance decreases accordingly.

Therefore, the magnetic flux generated by applying a voltage to the electromagnetic coil 15 is transmitted between the field core 16 and the cylindrical body 20 in the air gap S.
It passes through the peripheral wall part 2OA and the magnetic powder particles 21, and the peripheral wall part 18A of the outer cylinder 18 whose cross-sectional area has increased.

In this state, the force that magnetically couples the magnetic powder particles 21 is at its maximum, providing almost infinite resistance to the rotating cylindrical body 20 and strongly braking it.

Furthermore, since the braking mechanism, which generates a large amount of heat, is installed on the outside of the field core, it has excellent heat dissipation.Also, since the part that stores the magnetic powder is on the outside, it is possible to replace or replenish the magnetic powder each time. , there is no need to dismantle the whole thing.

As is clear from the above description, the electromagnetic brake of the present invention can adjust the braking force on the cylindrical body that is integrated with the rotating shaft by moving the position of the magnetic resistance adjustment tube in the axial direction. Compared to an electromagnetic brake that adjusts the braking force, it has excellent effects such as easy maintenance, high performance, and extremely good heat dissipation performance.

[Brief explanation of the drawing]

FIG. 1 is a half-part vertical side view showing a conventional electromagnetic brake, and FIG. 2 is a vertical side view showing an embodiment of the electromagnetic brake of the present invention. In the drawings, 1.19... rotation axis;
2... Cylinder, 3.16... Field core, 4... Fixing member, 5.15... Electromagnetic coil,
1 Rei 21...Magnetic powder grain, 16A...Annular groove,
16B...Outside wall, Lily...Mounting plate,
1st...outer cylinder body, 18A...peripheral wall part,
19A... End, 20... Cylindrical body, 2O
A... Peripheral wall part, 22... Hole, 23.
... Magnetism interruption part, 23A... End, 24...
・Magnetic resistance adjustment tube, 24a... end surface,
25A, 25B...Bearing, 26...Seal,
2Ma...Magnetic powder supply/discharge port, 2B...Lid piece, 29...Non-magnetic ring member, S...
void.

Claims (1)

[Claims] An annular field core having an annular groove that accommodates an electromagnetic coil, and an annular field core whose axially intermediate portion of the outer wall of the annular groove is a magnetism-interrupting part made of a non-magnetic material, and an annular field core arranged concentrically on the outside of this field core, an outer cylinder whose thickness is reduced to increase magnetic resistance; a cylinder whose peripheral wall is inserted into an annular gap between the field core and the outer cylinder, and which rotates integrally with a rotating shaft; The magnetic resistance adjusting tube is provided with a required amount of magnetic powder to be loaded into the gap, and a magnetic resistance adjusting tube whose inner circumferential surface is closely fitted to the outer circumferential surface of the outer cylindrical body so as to be movable in the axial direction. An electromagnetic brake characterized in that braking force is adjusted by displacement in the axial direction.