JP2002340034A - Non-excitation-operated electromagnetic coupling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an unstable transmission action of driving torque or braking torque due to a fluctuation in an effective magnetic flux according to magnetic flux leakage, in a non-excitation-operated electromagnetic coupling device designed to operate on a magnetic flux from a permanent magnet and terminate the operation by canceling the magnetic flux from the permanent magnet by excitation of a coil, wherein exposure of the permanent magnet results in leakage of the magnetic flux from the permanent magnet through a magnetic wall of equipment subjected to the transmission action of driving torque or braking torque, and thus a reduction in the effective magnetic flux contributing to the transmission action of driving torque or braking torque. SOLUTION: As the permanent magnet constituting the non-excitation-operated electromagnetic coupling device, a ringed permanent magnet 32 is used, whose parallel faces are magnetized in opposite polarities. One pole face is joined to the inside of an annular portion 24c of a boss 24, and the other pole face is joined to the side of a pole rotor 33. An outer circumferential edge of the pole rotor 33 is opposed via a gap G3 to an inner circumference of a projecting portion 31a of a shell 31 fixed to an outer circumference of a coil bobbin 28. The permanent magnet is thus protected against external exposure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a function of transmitting a driving torque or a braking torque based on a magnetic flux generated from a permanent magnet, and canceling out the magnetic flux from the permanent magnet with the magnetic flux based on the excitation of a coil. To an electromagnetic coupling device such as a non-excited operation type electromagnetic clutch for canceling the transmission of force.

[0002]

2. Description of the Related Art FIG. 4 shows a half-section longitudinal side view of a non-excited operation type electromagnetic clutch as a conventional non-excited operation type electromagnetic coupling device, in which 1 is a driven shaft, which sequentially includes a sleeve 2, a rotor 3 and a boss 4. The rotation is prevented by well-known means (such as a key and a key groove) (not shown). An armature support 5 is rotatably supported by the sleeve 2. 6
Is an armature which is held by the armature support 5 via a leaf spring 7. The restoring force of the leaf spring 7 acts in a direction to form a gap between the facing surfaces of the armature 6 and the rotor 3 when no magnetic attraction force acts between the armature 6 and the rotor 3. 5a is a gear.

[0003] 8 is a coil bobbin made of non-magnetic material,
A coil 10 is fixed at a position surrounding the boss 4 by an arm 9. Reference numeral 11 denotes a shell formed of a magnetic material and fixed to the outer periphery of the coil bobbin 8. Reference numeral 12 denotes a permanent magnet which has a ring shape and whose inner and outer peripheral surfaces are magnetized to different polarities. The inner peripheral surface of the permanent magnet 12 is fixed to the distal end peripheral surface extending in the radial direction of the boss 4, and the outer peripheral surface is opposed to the inner peripheral surface of the shell 11 via a gap. Reference numeral 14 denotes a magnetic wall of an OA device such as a printer that receives a transmission of a driving torque.

It is to be noted that whether the armature support 5 is external or not.
Functioning as an electromagnetic clutch when driven by
Or the armature support 5 is fixed to a fixing member.
And it will function as an electromagnetic brake. Conventional example
In the configuration of the electromagnetic clutch shown in FIG.
In the magnetic state, the shell 11 and the low
The outer peripheral side of the rotor 3, the armature 6, the inner peripheral side of the rotor 3, and
Magnetic flux φ generated in a closed magnetic circuit connecting boss 4₁By armati
Is attracted to the rotor 3 against the return force of the leaf spring 7.
As a result, the drive torque is transmitted. The transmission of this drive torque
Release of the magnetic flux from the permanent magnet 12 to the coil 10
φ ₁By applying current in the direction in which the magnetic flux that cancels out is generated,
Magnetic flux φ₁Cancels the magnetic attraction force, and returns the leaf spring 7
By releasing armature 6 from rotor 3
Is

[0005]

In the conventional configuration shown in FIG. 4, since a part of the permanent magnet 12 is exposed to the outside, a leakage magnetic flux φ ₂ is generated between the _two poles of the permanent magnet 12 by the electromagnetic clutch. The magnetic flux φ ₁ is generated toward the outside, and the magnetic flux φ ₁ is reduced, so that the transmission of the driving torque tends to be reduced. This leakage magnetic flux φ ₂ can be reduced by moving the magnetic wall 14 of the device receiving the drive torque away from the permanent magnet 12. However, when the electromagnetic clutch is applied to OA equipment such as a printer, the installation space of the electromagnetic clutch is limited, and the permanent magnet 12 and the magnetic wall 14 are not provided.
Are necessarily close together.

Therefore, the magnetomotive force of the permanent magnet 12 needs to generate an extra drive torque due to the above-mentioned leakage magnetic flux φ ₂ , and the permanent magnet 12 and the electromagnetic clutch including the permanent magnet 12 are increased in size. Tended to. On the other hand, the leakage magnetic flux φ ₂ depends on the distance between the permanent magnet 12 and the magnetic wall 14.
There were changes in the operating characteristics of the electromagnetic clutch for changing, difficult to obtain transduction activity proper driving torque, particularly when leakage flux phi ₂ is large, the coil 10 during release of the transmission of the drive torque accompanying the excitation of the coil 10 the flux phi ₁ with the excitation has a problem that release of the transmission of the drive torque by the magnetic flux in the opposite direction can not be performed accurately. Such a problem also occurs in the transmission of the brake torque in the non-excited operation type electromagnetic brake. An object of the present invention is to provide a non-excited operation type electromagnetic coupling device which solves the above-mentioned problems (problems) of a conventional device.

[0007]

According to the first aspect of the present invention, there is provided a non-excited operation type electromagnetic coupling device comprising: a driven shaft;
An armature supporter which is displaceably supported relative to the driven shaft in a circumferential direction of the driven shaft, and a cylindrical member which is supported by the driven shaft, rotates integrally with the driven shaft, and extends in the axial direction. A boss having an annular portion extending in a radial direction from an end in a direction opposite to a direction in which the armature support is located, and a boss located between the armature support and the boss, and supported by the driven shaft; A rotor integrally rotating with the driven shaft, an armature fixed to the armature support via a spring having a return force in a direction opposite to a direction in which the rotor is located, and an armature fixed in the axial direction of the boss. An exciting coil disposed to surround the extending cylindrical portion and supported by a fixing member; a shell formed of a magnetic material and fixed to face the outer circumferential surface of the exciting coil in a circumferential direction; A permanent magnet that provides an attractive force for attracting the armature to the rotor when the rotor is not excited, and a magnetic flux generated by the excitation of the excitation coil cancels out a magnetic flux generated from the permanent magnet. In the excitation operation type electromagnetic coupling device, a part of a magnetic circuit is formed, and an outer peripheral surface of the pole rotor includes a pole rotor facing with an air gap in an inner peripheral surface of the shell, and the permanent magnet is provided with the pole rotor. The magnetizing direction is the axial direction, and it is configured to be sandwiched and fixed between the inner surface of the annular portion extending in the radial direction of the boss and the pole rotor.

Further, according to the present invention, a leaf spring is used as the spring. Further, according to the third aspect, the permanent magnet has a ring shape, and the planes parallel to each other of the permanent magnet are magnetized to have different polarities.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, a specific example of a non-excited operation type electromagnetic clutch will be described as one embodiment of the electromagnetic coupling device of the present invention. 1 is a half longitudinal sectional side view of a non-excited operation type electromagnetic clutch in a magnetic coupling state, FIG. 2 is a half longitudinal sectional side view of a non-excitation operated electromagnetic clutch in a magnetic coupling disconnected state, and FIG. 3 is A in FIG. It is -A 'sectional drawing.

In FIG. 1 to FIG. 3, reference numeral 21 denotes a driven shaft. I have. An armature support 25 is rotatably supported on the sliding surface 22a of the sleeve 22. The armature support 25 forms a gear 25a that receives power transmission over the outer periphery of the drive source side end.
An armature 26 is held by the armature support 25 via a leaf spring 27. Restoring force of the plate spring 27 when the magnetic attraction force between the armature 26 rotor 23 does not work acts in a direction to form a gap G ₁ (see FIG. 2).

The rotor 23 has a groove 23a for forming a magnetic path and a non-magnetic portion 23b on a part of the surface facing the armature 26, and the other part is made of a magnetic material. The portion is provided with a protruding portion 23c extending in the axial direction in a direction opposite to the armature 26 side. Reference numeral 28 denotes a coil bobbin formed of a non-magnetic material,
a and is fixed by a plurality of arms 29. An excitation coil 30 is mounted on the coil bobbin 28. 31 is a shell made of a magnetic material having a cylindrical shape, is fixed to the outer periphery of the coil bobbin 28, the outer peripheral surface of the end portion of the rotor 23 side through the inner peripheral surface and the gap G ₂ of the protruding portion 23c of the rotor 23 It has a protruding portion 31 a for forming a magnetic path that faces the rotor 23 and is in the opposite direction to the rotor 23.

The boss 24 has a cylindrical portion 24b extending in the axial direction where the coil bobbin 28 is located, and an annular portion 24c extending radially from the end opposite to the direction in which the armature support 25 is located. And the annular portion 24c
Are spaced enough to prevent the passage of magnetic flux to the protruding portion 31a of the shell 31. Reference numeral 32 denotes a permanent magnet, which is formed in an annular shape, and the planes parallel to each other are magnetized with different polarities. The structure of the present invention is such that the permanent magnet 32 is sandwiched and fixed between the annular portion 24c of the boss and the pole rotor 33 described below, as shown in the figure, so that the permanent magnet is not exposed to the outside. There is a first characteristic of

Reference numeral 33 denotes a pole rotor formed of a magnetic material in an annular shape. The diameter of the inner peripheral surface is substantially the same as the inner diameter of the permanent magnet 32, and the diameter of the outer peripheral surface is slightly smaller than the inner diameter of the shell 31. I have decided. The pole rotor 33 has its left side joined to the right pole face of the permanent magnet 32,
The outer peripheral surface thereof is disposed so as to face each other with a gap G ₃ on the inner peripheral surface of the shell 31. Such a pole rotor 3
3 is a second feature of the configuration of the present invention. Reference numeral 34 denotes a magnetic wall of an OA device such as a printer that receives a power transmission action.

In the above configuration, first, the operation of transmitting the driving torque to the rotor 23 and driving the driven shaft will be described with reference to FIG. As shown in FIG. 1, when the magnetic pole polarity of the permanent magnet 32 is the N pole on the pole rotor 33 side, the permanent magnet 32 → the pole rotor 33 → the air gap G ₃ → the shell 31 →
The gap G ₂ → the outer peripheral portion of the rotor 23 → the armature 26 → the inner peripheral portion of the rotor 23 → the boss 24 → with the generation of the magnetic flux φ _{3 in the} closed magnetic path connecting the permanent magnet 32, the armature 26
A magnetic attractive force is generated between the opposing surfaces of the armature 26 and the rotor 23 against the return force of the leaf spring 27, and the armature 26 and the rotor 23 are connected. Thus, the driving torque given to the armature support 25 from the power source (not shown) via the gear 25a is transmitted to the driven shaft 21 via the leaf spring 27, the armature 26, and the rotor 23 in that order.

Next, the operation for canceling the transmission state of the driving torque will be described with reference to FIG. When energizing the coil 30, since the magnetic flux phi ₄ to offset the magnetic flux phi ₃ in the closed magnetic path of the magnetic flux phi ₃ as shown in FIG. 2 occurs, the armature 26 and the magnetic attraction between the rotor 23 cross disappears,
The gap G ₁ is generated between the facing surfaces each other and the armature 26 and the rotor 23 by the restoring force of the leaf spring 27. As a result, the driving torque applied to the armature support 25 from the external power source is not transmitted to the driven shaft 21 and cut off.

In each case of transmission and release of the driving torque, the present invention provides a
Is formed inside the annular portion 24c of the boss 24, so that no magnetic flux leaks to the magnetic wall 34 of a printer or other OA equipment to which the electromagnetic clutch of the present invention is applied.

The present invention is not limited to the structure of the above embodiment, and various modifications are possible. For example, the leaf spring 27 shown in FIGS. 1 and 2 can be replaced with another spring such as a coil spring by forming a spring mounting portion on the magnetic pole, for example. It is desirable to provide a spline mechanism for guiding the armature 26 in the axial direction as necessary. The permanent magnet 32 is not limited to the ring shape, and a plurality of permanent magnets may be annularly divided and arranged between the annular portion 24c of the boss 24 and the opposing surfaces of the pole rotor 33. Further, by setting the armature support 25 in a fixed state, it is needless to say that the armature support 25 can be used as a non-excitation operation type electromagnetic brake. That is, the present invention is a technique applied to a non-excitation type electromagnetic coupling device including both a non-excitation operation type electromagnetic clutch and an electromagnetic brake.

[0018]

Since the present invention is configured as described above,
It has the following excellent effects. (1) According to the first aspect of the present invention, the permanent magnet is fixed by being sandwiched between the inner wall of the annular portion extending in the radial direction of the boss and the pole rotor. As a result, the magnetic flux of the permanent magnet, which transmits the driving torque or the brake torque, leaks to the magnetic wall of the device to which the non-excited operation type electromagnetic coupling device according to the present invention is applied. Therefore, regardless of the presence or absence of the magnetic wall of the applied device in the vicinity of the permanent magnet, there is no change in the magnetic flux that serves to transmit the drive torque or the brake torque, and a stable drive torque or brake torque can be transmitted. In addition to the above, it is possible to reduce the space required for installing the electromagnetic coupling device on the applicable equipment. (2) According to the second aspect of the invention, in addition to the effect of the first aspect, the armature support mechanism that requires a return force in the direction opposite to the direction in which the armature support is positioned by the rotor is simplified. This is useful when applied to a small electromagnetic coupling device such as a micro clutch or a micro brake, for example. (3) According to the invention described in claim 3, claim 1 or 2
In addition to the effects of the invention described in (1), since the permanent magnet is a single unit, manufacturing, magnetizing, and assembling the electromagnetic coupling device can be simplified.

[Brief description of the drawings]

FIG. 1 is a half longitudinal sectional side view showing a configuration of a non-excitation operation type electromagnetic clutch according to an embodiment of the present invention, showing a state when driving torque is transmitted.

FIG. 2 is a half vertical sectional side view showing a state when the drive torque transmission of the electromagnetic clutch shown in FIG. 1 is cut off.

FIG. 3 is a sectional view taken along line AA ′ of FIG. 1;

FIG. 4 is a half vertical sectional side view showing a conventional example.

[Explanation of symbols]

21: Driven shaft 23: Rotor 24: Boss 24a: Boss sliding surface 24b: Boss cylinder Shaped portion 24c: annular portion of boss 25: armature support 26: armature 27: leaf spring 30: Excitation coil 31 Shell made of magnetic material 32 Permanent magnet 33 Pole rotor φ ₃ Magnetic flux of permanent magnet φ ₄・ ・ ・ ・ ・ ・ ・ Magnetic flux due to coil excitation

Claims (3)

[Claims] A driven shaft; an armature supporter which is supported by the driven shaft such that a circumferential relative position of the driven shaft is displaceable; and an armature supporter which is supported by the driven shaft and is integrated with the driven shaft. Rotate,
A boss having a tubular portion extending in the axial direction and an annular portion extending in a radial direction from an end in a direction opposite to a direction in which the armature support is located; and a boss located between the armature support and the boss; A rotor supported by the driven shaft and rotating integrally with the driven shaft; and an armature fixed to the armature support via a spring having a return force in a direction opposite to a direction in which the rotor is located, An exciting coil arranged to surround a cylindrical portion extending in the axial direction of the boss and supported by a fixing member; and a shell formed of a magnetic material fixed to face the outer circumferential surface of the exciting coil in a circumferential direction. A permanent magnet that provides an attractive force for attracting the armature to the rotor when the exciting coil is not excited,
Wherein the magnetic flux generated by the excitation coil cancels the magnetic flux generated from the permanent magnet.The non-excited operation type electromagnetic coupling device, wherein a part of a magnetic circuit is formed, and an outer peripheral surface of the pole rotor is formed. An inner surface of an annular portion extending in a radial direction of the boss and the pole rotor, wherein the pole rotor includes an opposing pole rotor having an air gap on an inner peripheral surface of the shell; A non-excited operation type electromagnetic coupling device, wherein the electromagnetic coupling device is sandwiched and fixed therebetween. 2. The non-excitation actuated electromagnetic coupling device according to claim 1, wherein a leaf spring is used as said spring. 3. The non-excited operation type electromagnetic device according to claim 1, wherein the permanent magnet has a ring shape, and respective parallel planes of the permanent magnet are magnetized with different polarities. Coupling device.