JP2011127649A - Electromagnetic coupling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic coupling device by preventing lubricating oil from adhering to the opposite surfaces of a rotor and an armature to secure required torque. <P>SOLUTION: This electromagnetic coupling device includes: the rotor and the armature respectively having opposite surfaces disposed opposite to each other; and a yoke provided with a coil for generating a magnetic flux to cause the opposite surface of the rotor and the opposite surface of the armature to be mutually attracted. A rotation center shaft part of the rotor penetrates the center of the yoke through a bearing to which lubricity is applied by lubricating oil, and in the opposite part where the opposite surface of the rotor is formed, a magnetic flux limiting part for limiting a magnetic flux in the radial direction of the rotor is formed in a predetermined area radially outside from the rotation center shaft part, whereby the magnetic flux limiting part is formed thinner than the other parts out of the opposite parts. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an electromagnetic coupling device that transmits and interrupts torque from a main drive side to a driven side by electromagnetic action.

Various electromagnetic coupling devices have been proposed in the past for transmitting and interrupting torque from the main drive side, which is the power source, to the driven side (see, for example, Patent Document 1).
A conventional electromagnetic coupling device generates a magnetic flux so that a rotor and an armature each having opposing surfaces arranged opposite to each other and an opposing surface of the rotor and an opposing surface of the armature are attracted to each other when a predetermined current is applied. And a yoke equipped with a coil for making the
The rotation center shaft portion of the rotor is inserted into the center of the yoke through a bearing having lubricity. As the bearing, a sliding bearing made of a sintered body impregnated with lubricating oil, or a rolling bearing filled with lubricating oil (grease) is used.
Moreover, the magnetic flux interruption | blocking hole (magnetic flux interruption | blocking part) which interrupts | blocks the magnetic flux of the radial direction of a rotor is formed in the opposing surface of a rotor.

JP 2008-309265 A

  In the electromagnetic coupling device having the above configuration, since the magnetic flux blocking hole is formed on the opposite surface of the rotor, when the electromagnetic coupling device is driven (when the rotor rotates), the lubricating oil of the bearing enters the magnetic flux blocking hole, It may adhere to the opposing surface of the armature. If it becomes so, there will be a problem that the friction coefficient of the opposing surfaces decreases, the opposing surfaces slip, and the torque necessary for the electromagnetic coupling device cannot be transmitted to the driven side.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an electromagnetic coupling device that can prevent a lubricating oil from adhering to opposing surfaces of a rotor and an armature and can stably secure a necessary torque.

  The present invention relates to a rotor and an armature each having opposed surfaces arranged opposite to each other, and a coil for generating a magnetic flux that attracts the opposed surface of the rotor and the opposed surface of the armature to each other when a current of a predetermined value is applied. In the electromagnetic coupling device in which the rotation center shaft portion of the rotor is inserted into the center of the yoke through a bearing provided with lubricity by a lubricating oil, the opposing portion forming the opposing surface of the rotor is provided. Among them, the magnetic flux in the radial direction of the rotor is limited by forming at least two magnetic flux restricting portions formed in a predetermined region radially outward from the rotation center shaft portion thinner than portions other than the predetermined region. It is characterized by doing so.

  In the above configuration, when a predetermined current is supplied to the coil, a magnetomotive force is generated by the coil, and a magnetic flux is generated around the coil. The magnetic flux is transmitted to the armature through the opposed portion of the rotor, and between the rotor and the opposed surface of the armature. When the armature moves to the rotor side in the axial direction of the rotation center shaft and the opposing surfaces are attracted to each other, the torque of the rotor is transmitted to the armature, and the armature rotates around the axis. The torque due to the rotation of the armature is transmitted to the driven device side.

The magnetic flux limiting part that limits the magnetic flux in the radial direction of the rotor is only formed thinner than the other part of the opposed part of the rotor, and is not a hole penetrating in the axial direction. Thus, when the lubricating oil of the bearing flows to the armature side, the lubricating oil is prevented from reaching the opposite surface of the rotor even if the lubricating oil flows to the armature side.
For this reason, the lubricating oil does not adhere to the opposed surfaces of the rotor and the armature, and the opposed surfaces to which the lubricating oil does not adhere are adsorbed, so that the rotational force of the rotor is transmitted to the armature as it is, and the electromagnetic coupling The torque required for the device can be obtained.
In addition, since the portions other than the predetermined region radially outward from the rotation center shaft portion in the rotor are not thinly formed (the original thickness is ensured), even if a thin magnetic flux limiting portion is formed. The required rigidity of the rotor can be ensured.

  In the electromagnetic coupling device of the present invention, a magnetic flux limiting portion formed thinner than the other portions of the opposed portion is formed in the opposed portion that forms the opposed surface of the rotor, thereby blocking the magnetic flux in the radial direction on the rotor. Since there is no hole, the lubricant from the bearing side does not move to the opposing surface of the rotor, and if the opposing surface of the armature is adsorbed to the opposing surface of the rotor, the rotational force of the rotor is transmitted to the armature as it is, and the electromagnetic coupling The torque necessary for the device can be secured stably.

The half sectional view which shows schematic structure of the electromagnetic coupling device which shows embodiment of this invention Cross section of the same rotor Similarly front view of the rotor The expanded sectional view of the magnetic flux restriction | limiting part which shows another embodiment

  Hereinafter, an electromagnetic coupling device according to the present invention will be described with reference to the drawings. This electromagnetic coupling device is used, for example, as an automatic opening / closing device for a sliding door of a vehicle. FIG. 1 is a half sectional view showing a schematic configuration of an electromagnetic coupling device, FIG. 2 is a sectional view of a rotor, and FIG. 3 is a front view of the rotor.

As shown in these drawings, the electromagnetic coupling device 1 according to the embodiment of the present invention includes a rotor 2 and an armature 3 having opposing surfaces 3a and 22a, respectively, and a yoke 4.
The rotor 2 is integrally formed by press molding from a cylindrical rotation center shaft portion 21, a facing portion 22 (also referred to as a base portion), and an annular portion 23. Note that the rotor 2 may be formed by other methods such as casting or cutting in addition to press forming.
The facing portion 22 is formed on one end side (armature 3 side) of the rotation center shaft portion 21. The facing portion 22 is formed to have a larger diameter than the rotation center shaft portion 21 and is formed in a disk shape in a direction orthogonal to the rotation center 21a. The annular portion 23 is formed at the radially outer end of the facing portion 22 by bending toward the other end.
The facing portion 22 of the rotor 2 and the armature 3 face each other in the direction of the rotation center 21a of the rotation center shaft portion 21, and the surface of the facing portion 22 that faces the armature 3 and the surface that faces the facing portion 22 of the armature 3 Respective surfaces 3a and 22a of the rotor 2 and the armature 3 are provided. A wave spring (not shown) is interposed between the facing surfaces 3a and 22a. The armature 3 is formed with a magnetic flux blocking hole 3b for blocking the magnetic flux.

Magnetic flux limiting portions 221 and 222 for limiting the magnetic flux in the radial direction of the rotor 2 are provided on the facing portion 22 of the rotor 2 in a region radially outward from the rotation center shaft portion 21 of the facing portion 22 and from the annular portion 23. Is also arranged radially inward (corresponding to a predetermined region). The magnetic flux limiters 221 and 222 are grooves formed at predetermined intervals in the circumferential direction with their positions shifted in the radial direction on concentric circles with the rotation center 21a of the rotor 2 as the center, and the opposing surfaces 22a are recessed. It is formed in a shape.
The magnetic flux limiting portions 221 and 222 are formed at only three locations on the facing surface 22a. With respect to the positional relationship between the magnetic flux limiting unit 221 and the magnetic flux limiting unit 222, the magnetic flux limiting unit 221 is disposed radially outward with respect to the magnetic flux limiting unit 222. Further, the magnetic flux limiting unit 221 and the magnetic flux limiting unit 222 are relatively displaced in the circumferential direction, and when the magnetic flux limiting units 221 and 222 are projected in the radial direction, the inner magnetic flux limiting unit 222 is outside. Between the two magnetic flux limiting portions 221.

In particular, the region between each of the opposing portions 22 of the rotor 2 in the circumferential direction of the magnetic flux limiting portions 221 and 222 is a thick portion with the original thickness, and the magnetic flux non-limiting portions 221a, which do not limit the magnetic flux. 222a. Moreover, the area | region between each in the radial direction of each magnetic flux restriction | limiting part 221,222 of the opposing part 22 of the rotor 2 is also a thick part with the original thickness. Thus, even if the thin magnetic flux limiting portions 221 and 222 are formed by providing the magnetic flux non-limiting portions 221a and 222a and the thick portion, the required rigidity of the rotor 2 is not impaired.
Needless to say, the number and shape of the magnetic flux limiting portions 221 and 222 may be changed as necessary. Further, the magnetic flux non-limiting portions 221 a and 222 a may be formed thinner than the original thickness of the facing portion 22 as long as the thickness is thicker than the magnetic flux limiting portions 221 and 222.

The yoke 4 is equipped with a coil 41 for generating a magnetic flux so that the opposed surface 22a of the rotor 2 and the opposed surface 3a of the armature are attracted to each other when a current of a predetermined value is applied.
The rotation center shaft portion 21 of the rotor 2 is inserted into the center of the yoke 4 via a bearing 5, which is lubricated with lubricating oil, in this case, a sliding bearing. The bearing 5 is composed of a sintered body impregnated with lubricating oil.

  In the above configuration, when a predetermined current is supplied to the coil 41, a magnetomotive force is generated by the coil 41 and a magnetic flux is generated around the coil 41. The magnetic flux passes through the facing portion 22 of the rotor 2 and is transmitted to the armature 3, and an attractive force is generated between the facing surfaces 22 a and 3 a of the rotor 2 and the armature 3. It moves along the rotation center 21a, and the opposing surfaces 22a and 3a are adsorbed. As a result, the rotor 2 and the armature 3 are locked, the armature 3 rotates about the rotation center 21a, and torque generated by the rotation of the armature 3 is transmitted to the driven device side.

  In the electromagnetic coupling device 1 configured as described above, the magnetic flux limiting portions 221 and 222 that limit the magnetic flux in the radial direction of the rotor 2 are formed thinner than the other portions of the opposing portion of the rotor 2. It is not a hole through 22. For this reason, even if the lubricating oil of the bearing 5 flows to the armature 3 side due to rotation of the rotation center shaft portion 21, the lubricating oil is prevented from reaching the facing surface 22 a of the rotor 2. For this reason, lubricating oil does not adhere to the opposing surfaces 22a, 3a of the rotor 2 and the armature 3.

  If the opposing surfaces 22a, 3a to which no lubricant is adhered are adsorbed, the rotational force of the rotor 2 is transmitted to the armature 3 as it is, and the torque required for the electromagnetic coupling device 1 is obtained. Further, since metal powder and fine unnecessary objects do not go to the armature 3 side, unnecessary objects do not enter between the facing surfaces 22a and 3a. For this reason, the opposing surfaces 22a and 3a are reliably adsorbed, and the torque required for the electromagnetic coupling device 1 is obtained.

  Further, the magnetic flux limiting portions 221 and 222 are not a hole penetrating the facing portion 22 but a recess formed in the facing surface 22a. For this reason, the burr | flash which generate | occur | produced by having formed by drilling the predetermined area | region of the opposing part 22 does not occur. For this reason, the troublesome work for removing a burr | flash becomes unnecessary.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the gist of the present invention. In addition, the specific configuration of each part is not limited to the above embodiment.
For example, in the above embodiment, the magnetic flux limiting portions 221 and 222 are formed in a groove shape in which the facing surface 22a is recessed toward the yoke 4 side. As another example of the magnetic flux limiters 221 and 222, a configuration as shown in FIG. FIG. 4 is an enlarged cross-sectional view of the magnetic flux limiting portions 221 and 222.
In the example shown in FIG. 4, the opposing surface 22 a is recessed toward the yoke 4 side, and the opposite side surface 22 b of the opposing surface 22 a (the surface on the yoke 4 side) is recessed toward the armature 3 side. Is made thinner than other portions of the facing portion 22.
Even if it comprises in this way, if lubricating oil does not adhere to the opposing surfaces 22a and 3a of the rotor 2 and the armature 3, and the opposing surfaces 22a and 3a which are not adhering lubricating oil will adsorb | suck, rotation of the rotor 2 will be carried out. The force is transmitted to the armature 3 as it is, and a torque necessary for the electromagnetic coupling device 1 is obtained.

  In the above embodiment, the magnetic flux limiting portions 221 and 222 are formed on a single concentric circle centered on the rotation center 21a of the rotor 2 at predetermined intervals in the circumferential direction. However, the magnetic flux limiting portions 221 and 222 may be formed on a plurality of different concentric circles around the rotation center 21a of the rotor 2 at predetermined intervals in the circumferential direction.

  By the way, in such an electromagnetic coupling device 1, lubricating oil may flow from the driven side to the rotor 2 side through the magnetic flux blocking hole 3b of the armature 3, and may adhere to the facing surfaces 22a and 3a. In such a case, it is preferable to provide a magnetic flux limiting portion that does not penetrate the armature 3 instead of the magnetic flux blocking hole 3b of the armature 3.

  DESCRIPTION OF SYMBOLS 1 ... Electromagnetic coupling device, 2 ... Rotor, 3 ... Armature, 3a, 22a ... Opposing surface, 4 ... Yoke, 5 ... Bearing, 21 ... Rotation center axial part, 21a ... Rotation center, 41 ... Coil, 221, 222 ... Magnetic flux Restriction part

Claims (1)

A yoke having a rotor and an armature each having opposed surfaces arranged opposite to each other, and a coil for generating a magnetic flux that attracts the opposed surface of the rotor and the opposed surface of the armature to each other when a current of a predetermined value is applied. In the electromagnetic coupling device in which the rotation center shaft portion of the rotor is inserted into the center of the yoke through a bearing provided with lubricity by lubricating oil,
By forming at least two magnetic flux limiting portions formed in a predetermined region radially outward from the rotation center shaft portion out of the opposing portions forming the opposing surface of the rotor, compared to portions other than the predetermined region, An electromagnetic coupling device characterized by limiting the magnetic flux in the radial direction of the rotor.

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