JPH07259905A - Unexciting operation type electromagnetic brake/clutch - Google Patents

Abstract

PURPOSE:To effectively fully utilize the surface area of a permanent magnet to generate efficient and strong attraction force regardless of a miniature size by forming the permanent magnet into a flat ring shape having small width in an axial direction, and moreover to be magnetized in a radial direction. CONSTITUTION:A permanent magnet ring 2a magnetized in a radial direction is inserted in the intermediate part in a radial direction on an outer side in the axial direction of an armature assembly 1a, and ringlike bypass gaps Gb having narrow width are provided in a line in the inside in the axial direction. While, the opening ends of the outer and inner poles Po and Pi of a yoke 6b having the U-shape cross section of a magnet assembly 3a are arranged opposite to inner side ends in the axial direction of an armature to be fixed to a static body 8 while housing an exciting coil 11 in an annular gap between the outer and inner poles Po and Pi. Consequently, the structure of the magnet assembly with a built-in coil can be simplified by providing a permanent magnet on an armature side to shorten a dimension in the axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet type non-excitation actuated electromagnetic brake or clutch (hereinafter referred to as electromagnetic brake / clutch). With the spread of AC servo motors and the emphasis on safety in recent years, there is an increasing demand for non-excitation actuated brakes / clutches, and in the yoke part of the magnet assembly among them. The permanent magnet type in which a permanent magnet is incorporated is widely used because it has the following features. 1) Compared to the spring type, it is smaller and has a larger braking torque and better response. 2) The holding torque can be controlled by adjusting the magnitude of the current (voltage) in the excited state of the coil. 3) By applying to the coil a voltage that is opposite to the current-carrying polarity at the time of releasing the brake, the magnetic flux of the permanent magnet and the magnetic flux of the exciting coil are superposed to generate a braking torque equal to or higher than the rated torque. 4) Excellent heat dissipation characteristics, slip service is possible, and torque capacity is large. The present invention relates to an improvement of a permanent magnet type non-excitation actuated electromagnetic brake / clutch having the above features.

[0002]

2. Description of the Related Art A conventional permanent magnet type non-excitation actuated electromagnetic brake is shown in cross-sectional views in an unenergized state and an energized state, respectively, in FIGS. 10 (A) and 10 (B). Shown in. The non-excitation actuated electromagnetic clutch is different in that the object to which the magnet assembly is fixed is not a fixed body but a rotating body, and other structures and actions are completely different from the electromagnetic brake. Since they are the same, the following explanation
I will describe Ki. Referring to FIG. 10A, the magnet and permanent magnet arranged near the left end in the figure
The mature assembly 1 includes a spline hub 5 and a spline 5
It is mounted movably in the axial direction with respect to the rotary shaft 9 via a, and between the spline 5a and this armature assembly 1 the direction in which the armature assembly 1 is constantly released from braking (Fig. A spring plate 4 is arranged to be pressed to the left). On the other hand, a magnet assembly 3 arranged axially opposite to the armature assembly 1 on the right side in the axial direction in the drawing has an outer pole Po and an inner pole Pi made of a magnetic material.
It has an outer yoke 6 forming an outer pole Po and an inner yoke 7 forming an inner pole Pi. The outer and inner yokes 6, 7 are connected to each other and are parallel to each other in the radial direction. A relatively large permanent magnet 2 is arranged in the space between the vertical portions 6a and 7a. Due to the magnetic flux φm generated by the permanent magnet 2 along the outer pole Po and the inner pole Pi of the magnet assembly 3, the armature assembly 1 resists the force of the spring plate 4 and splines. It is moved to the right in the figure along the spline 5a of the hub 5 and is attracted to the yoke 6 to frictionally contact the magnet assembly 3.

The magnet assembly 3 includes a vertical portion 7 of the yoke 6.
Since it is fixed to the fixed body 8 via a, the brake torque is applied to the rotational torque of the rotary shaft 9 via the spline hub 5, the armature assembly 1, the magnet assembly 3 and the like. With reference to FIG. 10B, when the coil 11 of the magnet assembly 3 is energized, a magnetic force is generated in a direction opposite to the magnetic flux φm generated by the permanent magnet 2 to cancel the magnetic flux φm, and the spring plate 4 is The armature assembly 1 is moved to the left in the figure by a force, a gap Ga is created between the armature 1 and the magnet assembly 3, and the braking action exerted on the torque of the rotary shaft 9 is It will be canceled. In this description, the spring plate 4 has been described, but the structure is not limited to the spring, and it goes without saying that a structure for releasing by utilizing the repulsive force of the magnet may be used. Incidentally, the cross-sectional views of the non-excited state and the excited state are respectively shown in FIG.
11A and FIG. 11B, the non-excitation actuated electromagnetic brake whose front view of the armature assembly is shown in FIG. 11 was filed as a prior application of the present applicant (Japanese Patent Application No. 5-3494
No. 63), but the armature release operation is unstable because there is no bypass gap for forming a bypass circuit as in the first embodiment of the present invention described later.

[0004]

The non-excitation actuated electromagnetic clutch / brake having the above structure has the following drawbacks and has been desired to be solved. 1) Since the permanent magnet is on the side of the magnet assembly, and the conventional permanent magnet is magnetized in the axial direction due to the structure of the magnet assembly, the axial dimension (L) becomes excessive. 2) In order to generate a sufficient magnetic force, it is necessary to increase the surface area of the permanent magnet, and it is extremely difficult to downsize it. 3) The magnet assembly consists of an outer pole, an inner pole,
Since it is composed of a coil and a permanent magnet, the structure becomes complicated and the manufacturing cost becomes high. As a means for improving these drawbacks, as shown in FIG. 11 which is a front view of the armature assembly, a non-excitation actuation type in which an annular strong and thin permanent magnet 2c is arranged in the armature assembly 1c. An electromagnetic brake was filed on December 28, 1993 as a prior application of the present applicant (Practical application No. 5-74415).
No.). Also, although not shown, a non-excitation actuated electromagnetic brake in which a strong and thin permanent magnet is arranged in the magnet assembly is a prior application of the applicant of the present application.
It was filed on the 8th (Japanese Patent Application No. 5-349463).
The above-mentioned Japanese Patent Laid-Open No. 5-349463 also discloses an embodiment in which a strong and thin permanent magnet 2c divided into a plurality of rings in the annular or circumferential direction is arranged in the armature assembly 1c, which will be described later. Since there is no magnetic gap or magnetic resistor for forming the bypass gap as in the embodiment of the present invention, the armature releasing operation is somewhat unstable as compared with the present invention.

[0005]

In order to solve the above problems, the present invention adopts the following means. 1) An arc-shaped permanent magnet obtained by dividing a flat ring whose axial length is shorter and thinner than the armature assembly into a plurality of pieces in the circumferential direction at predetermined intervals, and whose side wall is the axis line. Parallel and concentric, that is, with the thickness direction perpendicular to the axis
A ring-shaped or arc-shaped magnetic air gap, which is located outside or inside the armature and is concentric with the permanent magnet and has a size corresponding to the axial length of the armature assembly minus the length of the permanent magnet, or A magnetic resistor formed by brazing a non-magnetic material such as copper or stainless steel, that is, a bypass magnetic circuit is formed by exciting a coil by providing a bypass gap. 2) A flat length with a short axial direction A plurality of arc-shaped permanent magnets, which are obtained by dividing the ring into at least two pieces at predetermined intervals in the circumferential direction, and arc-shaped magnetic gaps at positions connecting these permanent magnets on the same circumference. A magnetic resistor that is provided or is formed by brazing a non-magnetic material such as copper or stainless steel, that is, a bypass resistor that is excited by a coil with a bypass gap interposed. The above problem is solved by further reducing the axial length of the non-excitation actuated electromagnetic brake / clutch having a different structure from the above item 1) by configuring the magnetic circuit.

[0006]

In the case of the constitutions of 1) and 2) of the solving means, when the coil is not energized, the magnetic flux φm of the permanent magnet is
Thereby attracting the armature assembly to generate a constant braking torque. When a current of a predetermined value is applied to the coil in a direction to cancel the magnetic flux φm generated by the permanent magnet, the electromagnetic resistance of the yoke increases the magnetic resistance to the magnetic flux φm generated by the permanent magnet. -The magnetic flux φm that has been attracted to each other is reduced or becomes zero, and the force is released by the release means such as the spring plate.
Since the mature assembly is released from adsorption with the yoke,
The brake torque becomes zero. Further, by adjusting and energizing in the range of φm> φc, the torque can be controlled as in the conventional non-excitation actuated electromagnetic brake. When the current flowing through the coil is further increased, the magnetic flux φ generated by the permanent magnet
Since m does not enter the yoke, a magnetic flux φc is formed in the yoke by the exciting current, but since the magnetic resistance due to the permanent magnet is large, the magnetic flux φ in the direction formed by the exciting current.
c cannot penetrate into the armature assembly.

That is, the magnetic flux φm generated by the permanent magnet and the magnetic flux φc generated by the exciting current repel each other at the facing portions of the armature assembly and the magnet assembly (yoke),
A magnetic pole having the same polarity as that of the magnetic pole at the end of the armature assembly is formed at the end of the magnet assembly (yoke) to generate a repulsive force between the two assemblies as shown in FIG. As a result, a release force such as a spring plate is assisted to release the armature assembly. When the current flowing through the coil is further increased, the magnetic force generated in the magnet assembly causes an arc.
The mature assembly is aspirated again as shown in FIG. Therefore, by adjusting the strength of the magnetic field formed by the exciting current and the strength of the magnetic field formed by the permanent magnet to an appropriate direction and value corresponding to the force of the releasing means such as the spring plate, and energizing, The torque can be controlled as in the conventional non-excitation actuated electromagnetic brake.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Cross-sectional views of a horizontal half body in a non-excited state and an excited state of a first embodiment according to the first aspect of the solving means according to the present invention,
These are shown in FIG. 1A and FIG. 1B, respectively. In each of the embodiments of the present invention shown below including FIG.
Arrangement of permanent magnets in a mature assembly (hereinafter referred to as an armature) is either a plurality of permanent magnets divided into arcs at predetermined intervals in the circumferential direction or a continuous annular set. However, the effects of the present invention are not limited to those described. 1A and 1B.
In FIG. 10, the same members as those shown in FIGS. 10A and 10B shown as the prior art are denoted by the same reference numerals, and only different points will be described to avoid duplication. 2A is an enlarged sectional half body side view of the flat cylindrical permanent magnet ring 2a having a shorter axial length than the armature.
FIG. 2B shows a plan view of the entire A reduction view of FIG. As shown in FIG. 2B, the permanent magnet ring 2a magnetized in the radial direction shown by the arrow is shown in FIG.
As shown in (B) of the same figure, the armature assembly (hereinafter referred to as armature) 1 is inserted into the intermediate portion in the radial direction on the outer side in the axial direction and aligned inward in the axial direction. A narrow ring-shaped bypass gap Gb is opened. On the other hand, a magnet assembly 3a having a U-shaped cross section
The open ends of the outer pole Po and the inner pole Pi of the gear 6b are arranged so as to face the axially inner end of the armature,
The exciting coil 11 is housed in an annular space between the outer pole and the inner pole and is fixed to the stationary body 8.

The bypass gap Gb may be provided axially outside the permanent magnet ring 2a as shown in FIG. The shape of the permanent magnet shown in FIGS. 1A and 1B has been described above as a continuous ring.
Needless to say, the shape may be an arc shape that is divided in the circumferential direction at a predetermined interval. The operation of the electromagnetic clutch / break having the above structure will be described. In the non-excited state, the armature 1a and the yoke 6 are driven by the magnetic field formed by the permanent magnet 2a as shown by the dotted line in FIG.
Since a magnetic flux φm that recirculates is generated, the armature 1a resists the force of the spring plate 4 and is attracted to the yoke 6b. When in the excited state, as shown by the solid line in FIG. 1B, the magnetic flux φm is generated by the current flowing through the coil 11 when the permanent magnet 2a is not present and is formed by the permanent magnet described above.
On the other hand, a magnetic field is formed in the opposite direction to form a magnetic flux φc that circulates the armature 1a and the yoke 6 (in FIG. 1B, the magnetic flux φm generated by the permanent magnet is shown for convenience of description. It is described as not existing). Therefore, in the yoke 6b, the magnetic resistance of the permanent magnet 2a against the magnetic flux φm increases and the magnetic flux φm decreases. Therefore, the armature 1a is moved leftward in the figure by the force of the spring plate 4 and released from the attraction with the yoke 6b.

FIG. 4 is a graph showing the relationship between the attractive force (+ P), the repulsive force (-P) and the current. In this figure, the conventional electromagnetic shake shown in FIGS. 10A and 10B is shown. The characteristic of the key is shown by a dotted line, and the characteristic of the electromagnetic brake of the present invention shown in FIGS. 1A and 1B is shown by a solid line. Further, FIG. 5 is a transverse half body sectional view showing a state in which the coil is excited by a larger current than that shown in FIG. 1 (B). That is, as shown in FIG. 4, when the coil current is increased, the magnetic flux φm that circulates between the armature 1a and the yoke 6b is reduced, so that the attractive force is reduced. When the current flowing through the coil increases and the magnetic flux φm generated by the permanent magnet 2a does not enter the yoke 6b,
A magnetic flux φc is formed in the yoke 6b by the exciting current, but the magnetic flux φc in the direction formed by the exciting current cannot penetrate into the armature assembly 1a because of the large magnetic resistance of the permanent magnet 2a. . That is, the magnetic flux .phi.m generated by the permanent magnet 2a and the magnetic flux .phi.c generated by the exciting current repel each other at the facing portions of the armature 1a and the yoke 6b, and have the same polarity as that of the magnetic pole at the end of the armature 1a. A magnetic pole is formed at the end of the yoke 6b and the armature 1a is formed.
A repulsive force is generated between the yoke and the yoke 6b. When the coil current is further increased, the magnetic flux φc generated by the permanent magnet 2a is overcome to form a magnetic flux φc which circulates between the armature 1a and the yoke 6b as shown in FIG. 5, and when the coil current is further increased, the magnetic flux φc is increased. The suction force due to increases.

FIG. 6A and FIG. 6B are horizontal half body sectional views in the suction state of the electromagnetic clutch / break as the second embodiment of the present invention by the solving means 2). .
6A shows the situation of the magnetic flux φm due to the permanent magnet in the attracted state corresponding to FIG. 1A, and FIG. 6B shows the situation of the magnetic flux φc due to the coil current corresponding to FIG. 1B. ing. FIG. 7 is a front view of the armature 1b, and FIG. 8 is a sectional view taken along line XX of FIG. Axial length (height)
Is the same as the armature 1b, and two flat arc-shaped permanent magnets 2b, 2b are provided at a predetermined distance in the circumferential direction in a radially intermediate portion slightly inward from the outer circumference of the armature 1b. And symmetrically arranged, and the two gaps between the two permanent magnets 2b are bypass gaps Gc, which are left as arc-shaped gaps as shown in FIG. 7 to form magnetic gaps, or nonmagnetic materials such as copper and stainless steel. Are filled in the voids by blazing or the like to obtain magnetic resistance. Reference numeral 5b in FIG. 7 is a spline that integrally rotates in the circumferential direction with respect to the rotation axis and is capable of relative movement in the axial direction. Since the operation is almost the same as that of the first embodiment, the description thereof will be omitted, but the coil 11 of the magnet assembly will not be described.
The magnetic flux φc generated from the magnetic flux φc reaches the outer side in the radial direction of the arc-shaped magnetic gap Gc from the inner pole Pi and then separates from the permanent magnet 2b, as shown by the path of the arrow in FIG. 9 as a perspective view. Further, after passing through the outer side in the radial direction of the permanent magnet 2b in the armature 1b in the circumferential direction, the direction is changed to the axial direction and the outer pole Po of the magnet assembly 3a.
To form a magnetic path back to.

[0012]

【The invention's effect】

(1) Since the permanent magnet inserted on the armature side as the secondary side is a flat ring shape with a small axial width and is magnetized in the radial direction, the surface area of the permanent magnet is effectively made. It can be utilized and it is small but efficient, and strong suction force is generated, so that the shape of the armature can be simplified and miniaturized. (2) Since the permanent magnet is provided on the armature side, the structure of the magnet assembly incorporating the coil is simple, the axial dimension is short, and the cost is reduced by using a small and simple structure. (3) As shown in FIG. 5, the adjustment accuracy of the exciting current required to obtain an appropriate attractive force and repulsive force can be reduced as compared with the conventional one, and a stable armature release operation can be obtained. (4) In the second embodiment, the dimension in the axial direction can be shortened and miniaturized as compared with the first embodiment. (5) In the first embodiment, the width of the armature is made wider than the width of the permanent magnet to provide the gap, so that the above-described effect is surely obtained. (6) In the second embodiment, the width of the armature and the width of the permanent magnet are made equal to each other and the gap is provided side by side with the permanent magnet, so that the width of the armature can be made narrower than that of the first embodiment. I can.

[Brief description of drawings]

FIG. 1 is a first non-excitation actuated electromagnetic brake according to the present invention.
In the embodiment, (A) of the figure is a horizontal half body sectional view showing a magnetic flux state by a permanent magnet, and (B) of this figure is a horizontal half body sectional view showing a magnetic flux state by a coil current.

FIG. 2A is an enlarged half sectional view of the permanent magnet shown in FIG. 1, and FIG. 2B is a reduction plane as viewed in the direction of arrow A showing the magnetization direction in FIG. 2A. It is a figure.

FIG. 3 is a partial side view in which a void or a non-magnetic portion is provided on the outer side in the axial direction of a permanent magnet.

FIG. 4 is a graph showing a relationship among a current (voltage) value, an attractive force (+ P), and a repulsive force (−P) when a coil is excited.

5 is a transverse half body cross-sectional view showing a magnetic flux state in a state where the magnetic field due to the coil current is larger than that shown in FIG. 1B.

FIG. 6A is a horizontal half sectional view showing a magnetic flux state by a permanent magnet of a second embodiment of a non-excitation actuated electromagnetic brake, and FIG. 6B is a magnetic flux by a coil current. It is a transverse half sectional view showing a state.

FIG. 7 is a plan view of the armature assembly of the second embodiment shown in FIG.

FIG. 8 is a developed side view of the XX section of FIG.

9 is a perspective view showing a magnetic path in the excited state shown in FIG. 6B as a second embodiment shown in FIGS. 6, 7 and 8. FIG.

FIG. 10 is a view showing a conventional non-excitation actuated electromagnetic brake, and FIG. 10A is a cross-sectional view of a horizontal half body in a non-excitation state.
(B) of this figure is a transverse half body sectional view in the excited state.

FIG. 11 is a front view of an armature assembly of a non-excitation actuated electromagnetic brake of the prior application.

[Explanation of symbols]

 1a, 1b Armature assembly 2a, 2b Permanent magnet 3a Magnet assembly 4 Spring plate 5 Hub 6b Yoke 8 Stationary or rotating body 9 Rotating shaft 11 Excitation coil Ga Armature gap Gb, Gc-a Gap formed in mature L Axial length of magnet assembly Po Outer pole Pi Inner pole φc Magnetic flux from coil φm Magnetic flux from permanent magnet

Claims (3)

[Claims] 1. A rotating shaft, which is arranged so as to be rotatable relative to the rotating shaft, is fixed to a stationary body or a rotating body, and its outer circumference and inner circumference are an outer pole and an inner pole, respectively. A magnet assembly having a double hollow cylindrical yoke having an annular space defined in the middle, and an exciting coil housed in the annular space of the yoke, and the magnet assembly described above. An armature assembly facing the opening end side of the annular space and integrally rotatable with the rotating shaft so as to be capable of relative movement in the axial direction, and this armature assembly is always provided with the magnet assembly. A releasing means such as a spring for pushing the armature assembly away from the solid body; and a state in which the magnet assembly is placed in the armature assembly and the magnet assembly is not excited, the armature assembly resists the pushing force of the releasing means. And a permanent magnet that is attracted to the magnet assembly to brake or rotate integrally with the magnet assembly, and a magnetic force that cancels the magnetic flux of the permanent magnet when the magnet assembly is excited. The non-excitation actuated electromagnetic brake, which is generated, releases the braking by releasing the armature assembly from the attraction by the releasing means, or releases the armature assembly from the connection with the rotating shaft. In the clutch, the permanent magnet is a strong ring that is short in the axial direction and has a thin wall thickness and a flat shape, or has a thin wall thickness in the radial direction and is divided into a number equal to these intervals by a predetermined number of intervals in the circumferential direction. A plurality of arc-shaped bodies, which are magnetized in the radial direction and have a predetermined width narrower than the thickness of the arc-shaped permanent magnets axially aligned at predetermined positions with respect to the permanent magnets, Other copper, non-excitation type electromagnetic vibration, characterized in that the bypass gap is located by a non-magnetic portion, such as stainless steel - key / clutch. 2. The non-excitation actuated electromagnetic brake according to claim 1.
In the key / clutch, the non-excitation actuated electromagnetic brake / clutch, wherein the permanent magnet is arranged on the outer side in the axial direction of the armature assembly. 3. A rotating shaft, which is arranged so as to be rotatable relative to the rotating shaft, is fixed to a stationary body or a rotating body, and its outer circumference and inner circumference are an outer pole and an inner pole, respectively. A magnet assembly having a double hollow cylindrical yoke having an annular gap defined in the middle and an exciting coil housed in the annular gap of the yoke and operating as a primary-side electromagnet. A solid body, the outer pole and the inner pole of the magnet assembly,
Armature assembly as a secondary side rotating body, which is mounted so as to be rotatable integrally with the rotary shaft so as to face the open end side of the rotary shaft and to be relatively movable in the axial direction, and this armature assembly. A releasing means such as a spring for constantly pressing the solid body in a direction of pulling it away from the magnet assembly; A permanent magnet for adsorbing to the magnet assembly against the pressure to brake the magnet assembly or rotating integrally with the magnet assembly, and when the magnet assembly is excited, the magnetic flux of the permanent magnet A magnetic force that cancels the magnetic field is generated to release the braking by releasing the armature assembly from the adsorption by the releasing means, or the armature assembly is released from the connection with the rotating shaft. In the non-excitation actuated electromagnetic brake / clutch to be removed, the permanent magnet has a plurality of arcuate shapes which are strong, short in the axial direction, thin in the radial direction, and thin in the circumferential direction. Is magnetized in the radial direction and is arranged at a predetermined position in the radial direction of the armature assembly, and the axial width of the permanent magnet is provided between the plurality of arc-shaped permanent magnets adjacent to each other. A non-excitation actuated electromagnetic brake, characterized in that an arc-shaped void having a width within the range of and continuous in the same circumferential direction, or a bypass gap made of a non-magnetic material such as copper or stainless steel is arranged. Ki / clutch.