JP2021120174A - Electromagnetic holder - Google Patents

Abstract

To provide an electromagnetic holder capable of attracting attracted objects one by one when a board thickness of the attracted object is thin, when a board width of the attraction part of the attracted object is narrow, when two sheets of the attracted objects are overlapped, or when the attracted objects are adjacent to each other.SOLUTION: By making a core 2 of an electromagnetic holder have a rectangular shape in which end face shapes are aligned and setting a thickness of a magnetic pole end part and a distance between magnetic poles to equal to or less than a width 21 of an attracted object or 50% or less, the attracted objects can be attracted one by one regardless of the presence or absence of the core as an adjacent attracted object and the core as an overlapped attracted object. Alternatively, the use of the core of the electromagnetic holder having high magnetic permeability enables fine adjustment of an electric current so as to prevent leakage magnetic flux and prevent erroneous attraction.SELECTED DRAWING: Figure 1

Description

The present invention relates to a component made of a soft magnetic material and an electromagnetic holder that adsorbs and holds a member, and particularly adsorbs and holds an adsorbed object having a thin plate thickness, an adsorbed object having a narrow adsorption portion, or an object to be adsorbed having an irregular shape. It is about the best electromagnetic holder to do.

As a means for gripping and transporting an object to be adsorbed made of a magnetic material, for example, a core to be adsorbed which is a component of an electromagnet one by one, an electromagnetic holder that holds the core to be adsorbed by electromagnetic adsorption is known. (Refer to Patent Document 1 etc.)
FIG. 2a is a vertical cross-sectional view of the conventional electromagnetic holder 1. The electromagnetic holder uses a core 2 made of a magnetic material and a coil 3 in which windings are wound many times. The core has an outer cylinder and an inner cylinder, and is composed of an integral or assembled disk that connects them at the bottom. The cylinder and the end face of the cylinder are flat.

When the coil is energized, magnetic poles N and S are induced at the ends of the cylinder and the cylinder, and opposite magnetic poles N and S are induced from this to the portion where the magnetic poles of the core to be attracted abut, and are attracted to the electromagnetic holder. When separating the adsorbed core, the energization may be turned off, but when the residual magnetic flux density of the core of the electromagnetic holder or the adsorbed core is large, the adsorbed core may not be separated due to the residual magnetic flux. At that time, if a reverse current of about 10% of the current initially passed through the coil is passed, the residual magnetic flux density becomes almost zero, so that the coil is separated smoothly.

In recent years, when assembling products and members, a combination of an image discrimination sensor and a robot has come to be widely used instead of the conventional automatic machine. Parts are supplied by a parts feeder, etc., and the direction of these parts is confirmed by an image sensor, etc., and the gripping device attached to the tip of the robot grabs the parts and places them in a designated place. The gripping device includes the electromagnetic holder of the present invention.

Japanese Unexamined Patent Publication No. 5-38695 JP-A-2018-62024 Japanese Unexamined Patent Publication No. 2015-101441

The problem with using a conventional electromagnetic holder is that it is a round electromagnetic holder that is normally used when parts are placed in contact with each other or when two or more thin plate materials are overlapped. There is a drawback that only one sheet cannot be adsorbed and held by simultaneously lifting the adjacent cores to be adsorbed, for example, or simultaneously lifting the overlapping lower cores.

This problem occurs because the magnetic flux emitted from the magnetic poles of the electromagnetic holder leaks to the outside without passing only through the core to be attracted, and this leak flux attracts another core or an overlapping core that is in contact with it. It occurs.

The adsorption force F of the electromagnetic holder is calculated by F [N] = B [T] * B [T] * Ae [m ² ] / 2 / μo. B is the magnetic flux density induced in the core to be adsorbed, Ae is the effective cross-sectional area of the adsorbed portion of the core to be adsorbed, and μo is the vacuum magnetic permeability. That is, when the adsorption force required to adsorb the adsorbed core is F, the adsorbed core can be adsorbed if the magnetic flux density appearing at both ends of the magnetic pole becomes equal to or higher than the magnetic flux density calculated by the above formula that gives F. It turns out that.

On the other hand, the magnetic flux density B induced from the electromagnetic holder is calculated by B = μ * H [T]. H is the strength of the magnetic field, and H = I [A] * N [number of windings] / Lm [m], and the unit is [A / m]. Lm is the average magnetic path length of the magnetic circuit. This average magnetic path length is the sum of the average magnetic path length of the core used for the electromagnetic holder and the length of the magnetic pole of the electromagnetic holder corresponding to the core to be attracted.

From these equations, it can be seen that the required suction force is the coil of the electromagnetic holder if the dimensions of the electromagnetic holder, the magnetic permeability of the core used for the electromagnetic holder, the magnetic permeability of the core to be attracted, and the number of coil windings are determined. It is determined by the magnitude of the flowing current.
In this case, if the magnetic permeability is low, the required magnetic flux density cannot be obtained unless the magnetic field is increased, and if the magnetic permeability is high, the required magnetic flux can be obtained with a smaller magnetic field. If the magnetic field is small, the leakage flux is naturally small, and if the distance between the magnetic poles of the electromagnetic holder is small, the path of the magnetic flux passing through the core to be attracted having low magnetic permeability is also shortened, so that the leakage flux is reduced.

As a result of diligent studies, the inventor of the present invention has solved these problems by creating a structure in which leakage flux is not generated as much as possible and selecting a material.

The invention of the present application includes the following aspects.
[1] An electromagnetic holder including a core made of a magnetic material whose end forms a magnetic pole and a coil in which a winding is wound many times, and has a dimension that the magnetic pole end face does not protrude from the object to be adsorbed at the time of adsorption. The electromagnetic holder.
[2] The electromagnetic holder according to [1], wherein the magnetic pole end face shape is two rectangular shapes that are separated and aligned.
[3] The electromagnetic holder according to [1] or [2], wherein the magnetic pole core of the electromagnetic holder is plate-shaped, and the distance between the magnetic poles and the thickness of the magnetic poles are 50% or less of the width of the suction portion of the object to be adsorbed.
[4] When the object to be adsorbed is a deformed product, a plurality of electromagnetic holders according to any one of [1] to [3] are arranged at two or more points on a line passing through the position of the center of gravity of the deformed product. Combined electromagnetic holder.
[5] A combination electromagnetic holder in which the end face directions of a plurality of electromagnetic holders according to any one of [1] to [3] are aligned so as to match the shape of the object to be adsorbed.
[6] The electromagnetic holder according to any one of [1] to [5], wherein the member used for the electromagnetic holder is made of a PC or PB permalloy.

In the electromagnetic holder of the present invention, the shape of the portion where the magnetic poles are in contact with the object to be adsorbed is devised so that the two magnetic poles in contact with the object to be adsorbed do not protrude from the adsorbed portion of the object to be adsorbed, and the distance between the magnetic poles is the width of the object to be adsorbed. The leakage flux can be reduced by the following.
Furthermore, the magnetic pole thickness of the electromagnetic holder and the distance between the magnetic poles are 50% of the width of the suction part of the object to be adsorbed.
Leakage flux can be reliably reduced by the following.

The shape of the end face of the magnetic pole of the electromagnetic holder is rectangular, that is, a substantially square shape that is long in one direction, preferably a rectangle. If the thickness of the magnetic pole is larger than the width of the above, the magnetic pole will protrude from the object to be adsorbed, so that the leakage flux will increase. In order to prevent this, the thickness of the magnetic pole is set to be less than or equal to the width of the adsorption portion of the object to be adsorbed, preferably 50% or less. Then, the area of the magnetic pole end faces becomes smaller, so the length of the two magnetic pole end faces in the alignment direction is adjusted.
By adopting such a magnetic pole end face shape, the leakage flux can be reduced even when the object to be adsorbed has an elongated shape.
The rectangular shape is substantially rectangular, but the corners do not have to be right angles, and it also represents an elongated shape extending in one direction, for example, which is close to an ellipse.

Since many cores to be adsorbed are generally processed cores, their magnetic permeability is very low. When a long distance is passed through a core with low magnetic permeability, the magnetic flux tends to leak due to its nature. Therefore, the distance between the magnetic poles was made as short as possible. It was set to be less than or equal to the plate width of the core to be adsorbed, or 50% or less of the plate width.

As described above, if the magnetic permeability is high, the required magnetic flux density can be obtained with a small magnetic field. Although rolled steel material SS400 for general structure is used in general electromagnetic holders and the like, it cannot be said that the magnetic permeability is so large even in soft iron and the like. In the present invention, a PC or PB permalloy having a very high magnetic permeability was used. Since the magnetic permeability at low current is very high, the number of windings can be reduced, and the high sensitivity makes it possible to finely adjust the magnetic flux density.

Recently, the number of irregularly shaped and small parts is increasing. When an electromagnetic holder is attached to the tip of a robot hand to attract and transport parts, there are many demands for increasing the moving speed. As shown in FIG. 3, when the deformed part is held at the center point 8 of the core by one conventional electromagnetic holder, moments of force act on both ends of the core 4 during vertical movement and rotational movement, causing the core to drop or rotate. Resulting in. However, if the electromagnetic holders 6 and 7 of the present invention hold the adsorption at two points, the line 10 passing through the center of gravity of the core and the points 11 and 12 where the core intersects, the core will drop or rotate even if the moving speed of the core is considerably high. There will be no such thing.

Further, as shown in FIG. 3, when the narrow core is attracted and held at the center point 8 with the conventional electromagnetic holder, the core outer cylinder of the electromagnetic holder itself protrudes to the outside of the core to be attracted and is adjacent to this portion. Another core that has been removed will also be adsorbed, causing problems such as falling during movement. However, as shown in the electromagnetic holders 6 and 7 of the present invention, when the magnetic poles do not protrude from the width of the core to be attracted, the adjacent cores are not attracted.
When the object to be adsorbed has a narrow irregular shape, the shape of the magnetic pole end faces is made into an aligned rectangle, and as shown in FIG. 3, the longitudinal direction of the aligned rectangle is the shape of the object to be adsorbed, that is, the extending direction. By aligning with, a larger adsorption force can be exhibited.
Further, if the alignment directions of the magnetic pole end faces are aligned so as not to protrude from the deformed object to be adsorbed, sufficient adsorption force can be exhibited even if it is not on the line passing through the center of gravity of the object to be adsorbed.

Furthermore, since permalloy with high magnetic permeability is used, the number of windings can be significantly reduced, and the current flow value can also be reduced, so that the running cost can be reduced. In addition, the magnetic flux density can be adjusted accurately by finely adjusting the current, and even if two sheets are overlapped, only the first sheet on the surface can be adsorbed and held.

As described above, according to the present invention, since the thickness of the core of the electromagnetic holder and the distance between the magnetic poles are adjusted to be smaller than the component width of the material to be adsorbed, the leakage flux is reduced and the adjacent contact material is used. It exerted the effect of eliminating adsorption. Further, by using PB and PC cores for the material cores, the number of windings is reduced and the energizing current to the coil is also reduced, so that only one core can be adsorbed even with a two-layered core. In addition, since the core shape is U-shaped, it can be produced in small quantities with a laser processing machine, eliminating the need for cutting and reducing costs. Since the number of windings has also decreased significantly, the winding processing cost has also been reduced.

In the embodiment of the present invention, a is a vertical sectional view and b is a bottom view. An embodiment of a conventional electromagnetic holder, where a is a vertical sectional view and b is a bottom view. It is a figure which showed an example of the core to be adsorbed of a narrow deformed product, the adsorption position by the conventional electromagnetic holder when adsorbing this core, and the adsorption position in this invention.

Embodiments of the electromagnetic holders (6, 7) according to the present invention will be described in detail with reference to FIGS. 1 and 3. FIG. 1A is a vertical sectional view according to the present embodiment, and FIG. 1B is a bottom view. The electromagnetic holders (6, 7) of the present invention are very simple. Screw holes and the like when attaching to the robot hand are omitted. It is composed only of a core (2) of an electromagnetic holder for passing magnetic flux and a coil (3) for passing an electric current. When there are a large number of orders, the core (2) of the electromagnetic holder may be die-made and pressed out, and when the quantity is small, it may be cut with a laser processing machine. High magnetic permeability PC permalloy or PB permalloy is used as the material. When the object to be adsorbed is smaller, it is better to use a PC permalloy having a low magnetic flux density but a high magnetic permeability. If this is not the case, PB permalloy, which has a low material price and a high magnetic flux density, is suitable. The thickness and width of the magnetic poles of the electromagnetic holder are adjusted according to the weight of the core to be attracted and / or the width. The thickness of the magnetic pole of the electromagnetic holder is adjusted so as not to protrude from the width of the core to be attracted, and when the weight is heavy, the width of the magnetic pole is widened and the area of the magnetic pole end face is adjusted to be large. Generally, if the thickness of the core to be adsorbed is about 0.05 to 2 mm, the distance between the magnetic poles may be 1 mm. After that, the number of coil windings and the magnitude of the current may be adjusted according to the shape and weight of the core to be adsorbed.

FIG. 3 shows an example of a deformed core to be adsorbed as 4. The center point of the core to be adsorbed is indicated by 8. In the case of the conventional electromagnetic holder 5, the core is attracted to the position of the center point 8 of the core. When the center point 8 of this core is adsorbed at one point and lifted upward on the paper surface, there is almost no problem if the speed is slow, but if the speed is increased a little, both tips of the core to be adsorbed There is a problem that a moment is generated and the core falls off. To prevent this, if the current is increased to increase the adsorption force, the magnetic flux of the magnetic poles of the electromagnetic holder will increase, and the cores adjacent to the core to be adsorbed will be adsorbed at the same time, or if two sheets are stacked. Causes a problem that both of them are adsorbed.

In the case of the present invention, when such a deformed core is adsorbed, it is adsorbed at two points, a line 10 passing through the center of gravity position 9 of the core and points 11 and 12 intersecting the core. When the core to be adsorbed is a thin linear shape, one point of the center point may be adsorbed. If the two points are attracted in this way, the core will not be dropped even if the ascending speed of the robot hand is maximized, and even if the robot hand is swiveled rapidly, it will not be dropped. Since the magnetic poles do not protrude from the width of the core to be attracted and the distance between the magnetic poles is short, there is almost no leakage magnetic flux and the adjacent contact cores are not attracted. In addition, since PC and PB permalloy are used, the current can be finely adjusted, so even if two sheets are overlapped, the second sheet will not be adsorbed.

According to the present invention, even if the cores to be adsorbed are minute, narrow, or irregularly shaped, and even if the cores to be adsorbed are in contact with each other or overlap each other, only one core is provided. It becomes possible to provide an electromagnetic holder capable of selectively adsorbing.

1 Electromagnetic holder 2 Electromagnetic holder core 3 Coil 4 Adsorbed core 5 Conventional electromagnetic holder 6 Electromagnetic holder of the present invention 7 Electromagnetic holder of the present invention 8 Center point of the adsorbed core 9 Center point of the adsorbed core 10 Adsorbed core Line passing through the center of gravity 11 Line passing through the center of gravity of the core to be attracted and the intersection of the core 12 Line passing through the center of gravity of the core to be attracted and the intersection of the core 21 Electromagnetic holder magnetic pole thickness 22 Electromagnetic holder magnetic pole distance 41 Adsorbed core Plate width N magnetic pole N
S magnetic pole S

Claims (6)

The electromagnetic holder including a core made of a magnetic material whose end forms a magnetic pole and a coil in which a winding is wound many times, and has a dimension that the magnetic pole end face does not protrude from the object to be adsorbed at the time of adsorption. .. The electromagnetic holder according to claim 1, wherein the magnetic pole end faces are two rectangular shapes that are separated and aligned. The electromagnetic holder according to claim 1 or 2, wherein the magnetic pole core of the electromagnetic holder is plate-shaped, and the distance between the magnetic poles and the thickness of the magnetic poles are 50% or less of the width of the suction portion of the object to be adsorbed. A combination characterized in that, when the object to be adsorbed is a deformed product, a plurality of electromagnetic holders according to any one of claims 1 to 3 are arranged at two or more points on a line passing through the position of the center of gravity of the deformed product. Electromagnetic holder. A combination electromagnetic holder in which the end face directions of a plurality of electromagnetic holders according to any one of claims 1 to 3 are aligned so as to match the shape of the object to be adsorbed. The electromagnetic holder according to any one of claims 1 to 5, wherein the member used for the electromagnetic holder is made of a PC or PB permalloy.

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