JP2822180B2 - Ring magnet forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ring magnet forming apparatus for forming a radially anisotropic ring magnet from magnetic powder.

[0002]

2. Description of the Related Art As a conventional ring magnet forming apparatus, for example, one shown in FIG. 8 is known. The lower ram 3 has the lower punch 2 inserted into the mold 1 and the lower ram 3 is inserted into the lower ram 3 so as to be movable up and down. Forming the lower core 4
And

The above-mentioned mold 1 is installed in a yoke 5 forming a part of a magnetic path, and an upper core 7 is inserted into an upper ram 6 arranged on the mold 1 so as to be able to move up and down. I have. Reference numeral 8 denotes an upper punch integrated with the upper ram 6.

Further, a lower magnetizing coil 9 is arranged around the lower ram 3, and an upper magnetizing coil 10 is arranged around the upper ram 6.

Next, the operation of the ring magnet forming apparatus having such a configuration will be described. First, a shoe box containing, for example, magnetic powder is slid over the upper surface of the mold 1 and the yoke 5 which is continuous with the mold 1, and the magnetic powder is dropped and filled into the molding space 11.

Next, the upper ram 6 is lowered, and the upper punch 8
At the position shown in the figure slightly protruding into the molding space 11 and at the position where the upper core 7 is in contact with the lower core 4, the lowering of the upper ram 6 is stopped.

Therefore, the upper magnetizing coil 10 and the lower magnetizing coil 9 are energized so as to have mutually repelling polarities. In this energized state, the upper ram 6 is lowered again, and the upper punch 8 forms The magnetic powder is pressed until a predetermined pressure is reached.

At the end of the pressurization, the energization is stopped, and then the energization in the opposite direction to that of the coils 9 and 10 is performed to demagnetize the compact made of magnetic powder. Thereafter, the lower ram 3 and the upper ram 6 are raised, and the lower core 4
Then, the lower compact 2 is raised to take out the above-mentioned molded body.

In this manner, the lower magnetizing coil 9 and the upper magnetizing coil 10 which are large-diameter air-core coils are connected to the lower ram 3.
And the upper ram 6 is set to be a magnetic core, respectively,
Moreover, the magnetic powder is radially oriented by flowing the repulsive magnetic fluxes from each of the cores 4 and 7 toward the mold 1, thereby manufacturing a radially anisotropic ring magnet.

[0010]

However, in such a conventional ring magnet forming apparatus, since the lower magnetized coil 9 and the upper magnetized coil 10 have a large diameter, each of the rams 3 and 6 has a magnetic circuit. Therefore, it was necessary to considerably increase the magnetomotive force of each of the coils 9 and 10.

[0011] For this reason, in addition to the increase in the size of the equipment, the cost is increased. In addition, it takes a long time to rise and fall the magnetization time for orientation and the energization time for demagnetization. In this case, it is necessary to provide an energization suspension time (exceeding the time constant due to the self-inductance of the coil), and as a result, the time required to form one ring magnet becomes, for example, 25 to 45 seconds. there were.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and a strong orientation magnetic field can be concentrated on a magnetic powder while shortening a conduction time and a conduction current by shortening a magnetic path length. It is an object of the present invention to provide a ring magnet forming apparatus capable of producing a desired ring magnet at a low cost with a small facility by appropriately and efficiently.

[0013]

To achieve the above object, a ring magnet forming apparatus according to the first aspect of the present invention comprises:
A lower core comprising a lower core magnetic part and a lower core non-magnetic part, which is inserted into the lower punch so as to be able to move up and down to form a ring-shaped molding space in the die together with the lower punch; A small-diameter ring-shaped yoke supporting the outer peripheral portion from below, a lower magnetized coil provided on the lower surface side of the yoke, and a magnetic material covering the periphery being in contact with the yoke, and moving on the mold; An upper magnetized coil, wherein the upper magnetic coil is arranged so that the magnetic material covering the periphery is brought into contact with a top surface of the mold or a dice supporting the mold.
An upper punch for compression-molding the magnetic powder filled in the molding space is inserted into and removed from the center of the upper magnetized coil so that the lower end can contact the upper end of the lower core in the upper punch. An upper core comprising an upper core magnetic portion and an upper core non-magnetic portion is inserted so as to be able to freely enter and exit.

In the ring magnet forming apparatus according to the second aspect of the present invention, the lower core non-magnetic portion is provided with a magnet.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 21 denotes a non-magnetic lower punch which is inserted into a mold 22 so as to be able to move in and out, and 23 is inserted into the lower punch 21 so as to be movable up and down. Is a lower core forming the molding space 24. The lower core 23 includes a lower core magnetic part 23a and a lower core nonmagnetic part 23b.

Reference numeral 25 denotes a small-diameter ring-shaped yoke for supporting the outer peripheral portion of the mold 22 from below, and 26 is provided on the lower surface side of the yoke 25 so that a magnetic material 27 covering the periphery contacts the yoke 25. The lower magnetized coil.

On the other hand, 28 is movably disposed on the mold 22 so that the magnetic material 29 covering the periphery is brought into contact with the upper surface of the mold 22 or a die stopper 30 for supporting the mold 22. Upper magnetized coil. The outer periphery of the die stopper 30 and the yoke 25 is supported by a backup member 31.

An upper punch 32 is inserted freely into and out of the center of the upper magnetized coil 28 to compress and form the magnetic powder filled in the molding space 24. The lower end is the lower core magnetic part 23a.
The upper core 33 is composed of an upper core magnetic part 33a and an upper core non-magnetic part 33b.

A coil hanger 34 supports the upper core 33. The coil hanger 34 is supported by an upper ram 35. The upper ram 35 has the upper punch 32 attached to the lower end thereof.
The upper core 33 is inserted through the center of the upper ram 16.

Reference numeral 36 denotes a lower ram having an upper end to which the lower punch 21 is attached.
The lower core 23 is inserted through the center of the. Also, 37
Is a magnet buried inside the lower core non-magnetic portion 23b of the lower core 23.

Next, the operation will be described. First, mold 2
The bottomless shoe box 41 containing the magnetic powder 40 is slid on the upper surface of the mold 2 as shown in FIG.

Next, the lower core non-magnetic portion 2 of the lower core 23
The lower core 23 is raised into the lower punch 21 as shown in FIG. 3 until the magnet 37 in 3b enters the shoe box 41. Thus, the magnetic powder 40 in the shoe box 41 is attracted to the outer periphery of the lower core nonmagnetic portion 23b near the magnet 37.

Subsequently, the lower core 23 is
Lower inside. By doing so, the magnetic powder 40 on the outer periphery of the lower core nonmagnetic portion 23b is filled in the molding space 24. Then, the upper ram 35 is lowered so that the lower end of the upper punch 32 is located on the upper surface of the mold 22.

At this time, as shown in FIG. 1, the magnetic material 29 on the side of the upper magnetized coil 28 is
Make contact with 0.

Subsequently, the upper and lower magnetized coils 28 and 26 are energized to generate a magnetic field. This magnetic field may be either a static magnetic field or a pulsed magnetic field.

Then, in this magnetic field application state, the upper core 33 is lowered, and the magnetic powder 40 in the molding space 24 is pressed as shown in FIG. After this press, the mold 22 and the lower core 23 are lowered by performing demagnetization, and the upper ram 35 and the upper core 33 are further raised.
As shown in FIG. 5, the molded product 45 having the upper portion protruding outside in the molding space 24 is taken out, and the molding operation is completed.

The flow of the magnetic flux generated by the energization of the lower magnetized coil 26 and the upper magnetized coil 28 is as shown in FIG. 6, and the magnetic flux generated by the lower magnetized coil 26 is transferred from the lower core magnetic portion 23a to the gold. Mold 22, Yoke 2
5, flow sequentially to the magnetic material 27 and the lower core magnetic part 23a.

On the other hand, the magnetic flux generated by the upper magnetized coil 28 is transmitted from the upper core magnetic portion 33a to the mold 22, the yoke 25,
It flows sequentially through the magnetic material 29 and the upper core magnetic part 33a. Therefore, the magnetic powder 40 in the molding space 24 is radially oriented by these two loop magnetic fluxes.

Accordingly, looking at such a magnetic path, the magnetic flux does not flow as a magnetic path through a conventional press machine or the like, so that the magnetic path length is significantly shortened and the magnetic resistance is reduced. There is no need to generate a large magnetomotive force.

As a result, the effect that the back electromotive force due to the self-inductance of each of the coils 26 and 28 can be reduced, and the switching between the magnetization and the demagnetization can be instantaneously realized with the time constant kept small.

In the above embodiment, the case where the lower punch 21 and the upper punch 32 are formed of a non-magnetic material has been described. The magnetic resistance of the magnetic path can be further reduced.

FIG. 7 shows a ring magnet forming apparatus capable of forming a large number of molded products. In general, since a ring magnet is formed by using one magnetic circuit as a unit, when a large number of pieces are formed, a magnetic flux is disturbed among a plurality of molds, and a magnetic flux passing through a molding space is disturbed, resulting in a bias.

However, in the present invention, as described above, the mold 2
2 and the ring-shaped yoke 25, one independent small magnetic circuit is formed, so that the above-described mold 22 and yoke 25 are connected to the non-magnetic backup member 3.
If the magnets are arranged side by side as shown in FIG. 1, it is possible to assemble a ring magnet forming apparatus capable of taking a large number of pieces with uniform orientation without disturbance of magnetic flux.

As a result, the cycle time for producing one ring magnet can be greatly reduced by the multi-cavity.

[0035]

As described above, according to the first aspect of the present invention, the lower core magnetic material is inserted into the lower punch so as to be able to move up and down to form a ring-shaped molding space in the mold together with the lower punch. A lower core comprising a non-magnetic part and a lower core,
A ring-shaped yoke having a small diameter for supporting an outer peripheral portion of the mold from below, a lower magnetized coil provided on a lower surface side of the yoke, and a magnetic material covering the periphery being in contact with the yoke; An upper magnetized coil movably disposed on the mold such that a magnetic material covering the periphery is brought into contact with a top surface of the mold or a dice supporting the mold, and a center of the upper magnetized coil. An upper punch for compressing and molding the magnetic powder filled in the molding space is inserted into and out of the upper part, and in the upper punch, the upper core magnetic part and the upper part so that the lower end can contact the upper end of the lower core. Since the upper core consisting of the core non-magnetic part is inserted so that it can be freely inserted and removed, a strong orientation magnetic field can be concentrated and efficiently applied to the magnetic powder while shortening the magnetic path length and reducing the energization time and current. To the place Effect that the ring magnet can be manufactured in low cost with a small equipment can be obtained.

According to the second aspect of the present invention, since the magnet is provided in the lower core non-magnetic portion, a sufficient amount of magnetic powder in the shoe box can be filled in the molding space. Is obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a ring magnet forming apparatus according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a procedure for forming a ring magnet by the ring magnet forming apparatus of the present invention.

FIG. 3 is a cross-sectional view showing a procedure for forming a ring magnet by the ring magnet forming apparatus of the present invention.

FIG. 4 is a sectional view showing a procedure for forming a ring magnet by the ring magnet forming apparatus of the present invention.

FIG. 5 is a sectional view showing a procedure for forming a ring magnet by the ring magnet forming apparatus of the present invention.

FIG. 6 is an explanatory diagram showing a flow of a magnetic flux generated when the ring magnet of FIGS. 1 to 5 is formed.

FIG. 7 is a cross-sectional view showing a ring magnet forming apparatus according to another embodiment of the present invention.

FIG. 8 is a sectional view showing a conventional ring magnet forming apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 Die 22 Lower punch 23 Lower core 23a Lower core magnetic part 23b Lower core non-magnetic part 24 Molding space 25 Yoke 26 Lower magnetized coil 27 Magnetic material 28 Upper magnetized coil 29 Magnetic material 30 Dice stop 32 Upper punch 33 Upper core 33a Upper part Core magnetic part 33b Upper core non-magnetic part 37 Magnet

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) H01F 41/02 B22F 3/087

Claims (2)

(57) [Claims] 1. A non-magnetic lower punch which is inserted into a mold so as to be able to move in and out, and is inserted into the lower punch so as to be able to move up and down to form a ring-shaped molding space in the mold together with the lower punch. A lower core comprising a lower core magnetic portion and a lower core non-magnetic portion, a small-diameter ring-shaped yoke for supporting the outer peripheral portion of the mold from below, and a lower surface side of the yoke for covering the periphery. A lower magnetized coil in which a magnetic material is in contact with the yoke, and movably disposed on the mold,
An upper magnetized coil in which a magnetic material covering the periphery is brought into contact with an upper surface of the mold or a die stop supporting the mold, and is inserted so as to be freely inserted into and removed from a center portion of the upper magnetized coil, and is inserted into the molding space. An upper punch for compressing and molding the magnetic powder filled into the upper core, and a lower end is inserted into the upper punch so as to be vertically movable so that a lower end thereof can contact the upper end of the lower core. A ring magnet forming apparatus comprising: an upper core comprising: 2. The ring magnet forming apparatus according to claim 1, wherein a magnet is provided in the lower core non-magnetic portion.