JPS6352660A - Multipolar electromagnetic brake - Google Patents

Abstract

PURPOSE:To obtain an electromagnetic brake without exciting a shaft, by providing an exciting iron core with an axis parallel to that of the shaft to the extended section in the direction of outside circumference of the shaft, and by exciting adjoining exciting iron cores in reverse. CONSTITUTION:Four pieces of exciting iron cores for brake 12, 14, 16 and 18 made of magnetic substance are installed uprightly to an annular substrate 10 movably fitted to a shaft 54 so that the axis may be parallel to that of the shaft 54. Each of these exciting iron cores 12, 14, 16 and 18 are wound with exciting windings for brake 20, 22, 24 and 26, which is composed of a single conductor. The adjoining windings are mutually wound in the opposite direction. Consequently, when windings 20-26 are electrified at the same phase, adjacent poles are excited in reverse. The flux passing through an exciting iron core is drawn into adjoining two exciting iron cores through an annular armature 56, so that the flux does not pass the shaft 54, and the shaft 54 is not therefore excited.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electromagnetic brake for a servo motor, and particularly to a multipolar electromagnetic brake.

[Conventional technology]

Conventionally, single-pole electromagnetic brakes have been used as electromagnetic brakes for servo motors. FIG. 3 shows its cross-sectional view. A brake excitation core 50 equipped with a brake excitation winding 52 is inserted into the outer periphery of the shaft 511 of the servo motor, and when the winding 52 is energized and energized, the magnetic flux due to the excitation also passes through the shaft 54. Armature 56
to go into.

[Problem that the invention seeks to solve]

As described above, when the magnetic flux passes through the shaft, it becomes energized if the shaft is made of magnetic material. Therefore, surrounding iron powder etc. are adsorbed during this time.

At this time, iron powder may also enter the shaft bearing, causing damage to the bearing and shaft. Furthermore, a suction force acts between the balls of the bearing and the inner and outer rings, impeding smooth bearing operation and shortening the life of the bearing. In order to solve these problems, if the retainers and shields for shafts and bearings are made of non-magnetic materials, this has the disadvantage of high costs.

Therefore, in order to solve these problems, the present invention aims to provide a low-cost electromagnetic brake that does not require excitation of a servo motor shaft.

[Means for solving problems]

In view of the above-mentioned objects of the invention, the present invention provides an electromagnetic brake for use in a servo motor, which is an electromagnetic brake for use in an even number of brakes that are disposed on an extension in the outer circumferential direction of a shaft of the servo motor and have an axis parallel to the axis of the shaft. It is equipped with an excitation core and a brake excitation winding wound around each of the brake excitation cores, and during operation, the adjacent brake excitation cores are excited to opposite magnetic poles to generate a brake excitation magnetic flux. A multi-polar electromagnetic brake is provided, characterized in that a closed loop is formed between the excitation iron cores for the brake that are adjacent to each other, and the excitation iron cores do not pass through the shaft.

[For production]

According to the above means according to the present invention, when the respective brake excitation windings are energized, the magnetic poles of the adjacent brake excitation iron cores are reversed, so that the magnetic flux is attracted to the adjacent brake excitation iron cores. No magnetic flux passes through the shaft of the central servo motor surrounded by each brake excitation core, and the shaft is not excited.

〔Example〕

The present invention will be described in more detail below based on embodiments shown in the accompanying drawings. FIG. 1 is a plan view of a multipolar electromagnetic brake according to the present invention (a sectional view taken along arrow line 1-1 in FIG. 2);
The figure is a front view of FIG. 1, and FIG. 4 is a sectional view of the servo motor.

First, a schematic structure of a servo motor equipped with an electromagnetic brake will be explained with reference to FIG. A rotor 74 held by the shaft 54 is disposed between stators 76 fixed to the housing 80 .

This shaft 54 is rotatably supported by a front bearing 72 and a rear bearing 70 held in a housing 80.

An electromagnetic brake that brakes the rotation of the rotor 74 via the shaft 54 is disposed near the rear bearing 70. A brake excitation winding 52 is wound around the excitation core 50 . On the other hand, an end plate 64 which is a fixed brake pad is fixed to the brake excitation core 50 with a screw 66 via a cylindrical member 68. Between this end plate 64 and the excitation iron core 50 for the brake, there are a fixed plate 60 and an armature 56 which are movable brake bands, and two which are brake plates.
Friction plates 58 and 62 are arranged alternately in parallel. These two γ oscillation plates 58 and 62 engage with a brake spline 78 fixed to the shaft 54 and are slidable in the axial direction. The above friction plates 58, 62 and fixed plate 60
The armature 56 is pressed against the end plate 64 by a braking force generating spring (not shown).

The armature 56 is made of a magnetic material, so when the brake excitation winding 52 is energized, it overcomes the biasing force of the braking force generating spring and attracts the armature 56 in a direction away from the end plate 64, causing the friction plate 58, 62 and the end Plate 64, fixed plate 6
0 and the armature 56, and the braking is released. The electromagnetic brake described above is just one example; for example, there is a case where there is only one friction plate, and there is also a type of motor in which a brake device is disposed in front of the rotor 74.

During the brake release period of the shaft 54, magnetic flux passes through the shaft 54 as indicated by the arrow in FIG. The problem caused by this is as described above, and an embodiment for solving the problem is shown in FIGS. 1 and 2. The axis of the annular group viIO loosely fitted on the shaft 54
Four brake excitation cores 12, 14, 16, and 18 made of magnetic material are erected parallel to the axis of the brake. The four exciting cores 12, 14, 16, 18
are arranged at equal angles at 90 degree intervals and concentrically with respect to the central axis of the shaft 54. Each of these exciting cores 12, 14, 16.

18 has brake excitation windings 20 , 22 , 24 ,
26 is equipped with winding. In this embodiment, one conducting wire constitutes four windings, and adjacent windings are wound in opposite directions. That is, the windings 20 and 24 are wound to the right, and the windings 22 and 26 are wound to the left. Each of these windings 20, 22, 24, 26 may be composed of four separate conductors. Each winding 20, 22
, 24 and 26 in the same phase, opposite magnetic poles are excited for each adjacent exciting core. For example, the top surface of each exciting core 12, 14, 16, 18 in FIG.
, S, and N. In this case, the flow of magnetic flux is as shown by the arrows in FIGS. 1 and 2.

For example, the magnetic flux that has passed through the brake excitation core 14 passes through the annular armature 56 and passes through the two adjacent excitation cores 1.
2 and 16, and does not pass through the shaft 54.

In order to excite mutually opposite magnetic poles in adjacent excited iron cores, in addition to reversing the winding direction of the windings mentioned above, it is also necessary to reverse the phase of the energized current (apply voltage in opposite directions). But it is possible. Further, the number of excitation cores and windings is not limited to four, but may be six or eight, for example. The electromagnetic brake according to the present invention is used with a servo motor to provide accurate rotational positioning of the servo motor, but it can also be used to release the brake of a general motor.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, an even number of excitation iron cores for brakes are provided, and the adjacent excitation iron cores for brakes are excited to the opposite polarity, so that the magnetic flux between the adjacent excitation iron cores is This makes it possible to provide a multi-polar electromagnetic brake that forms a closed loop and does not pass through the servo motor shaft. Therefore, there is no need to use non-magnetic materials such as stainless steel for the shaft material.
It is possible to use low-cost iron materials. Furthermore, the bearing retainer and shield do not need to be made of non-magnetic material.

[Brief explanation of drawings]

FIG. 1 is a plan view of a multi-polar electromagnetic brake according to the present invention (a sectional view taken along arrow line 1-1 in FIG. 2), FIG. 2 is a front view of the multi-polar electromagnetic brake shown in FIG. 1, and FIG. is a cross-sectional view of a conventional single-pole electromagnetic brake, and FIG. 4 is a cross-sectional view of a servo motor equipped with a conventional single-pole electromagnetic brake. DESCRIPTION OF SYMBOLS 10... Annular board, 12, 14, 16, 18... Brake excitation core, 20, 22, 24, 26... Brake excitation winding, 50... Brake excitation core, 52... - Excitation winding for brake, 54...shaft, 56... armature. +4 22 Figure 1, Figure 2, l. Figure 3

Claims (1)

[Scope of Claims] 1. An electromagnetic brake for use in a servo motor, which is disposed on an extension of the shaft of the servo motor in the outer circumferential direction,
An even number of brake excitation cores having axes parallel to the axis of the shaft, and a brake excitation winding wound around each brake excitation core are provided. A multi-polar electromagnetic brake characterized in that the excitation cores are excited to opposite magnetic poles so that the brake excitation magnetic flux forms a closed loop between the adjacent brake excitation cores and does not pass through the shaft. 2. The multipolar electromagnetic brake according to claim 1, wherein the number of the brake excitation iron cores is four, and the brake excitation cores are arranged concentrically and equiangularly with respect to the axis of the shaft. 3. The even number of excitation windings for brakes are composed of one conductive wire, and are wound in opposite directions around each of the adjacent excitation cores for brakes, as claimed in claim 1 or 2. The multi-polar electromagnetic brake described in .