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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an
electromagnetic vibrator used for vibration transport devices and the like of materials and
products. [Background Art] As a transport apparatus for materials, products, etc., an
electromagnetic vibrator is attached to a horizontal or inclined bowl-like tray, and the tray is
vibrated to be transported. Common electromagnetic vibrators are often single-phase alternating
current with a commercial frequency power source, and the structure is generally a large number
of devices utilizing a two mass resonance system. These general structures are shown in FIG. 1
((a) is a front view, (b) is a side view) and FIG. In this figure, the electromagnetic vibrator includes
a yoke (a yoke) (]), a coil (2) attached thereto to generate a magnetic flux, a movable iron core (3)
arranged with an air gap therebetween, and a resonant spring (41). , (41 'and. In the figure, (5) is
a tray mass, (6) is a counter mass, and (7) is a support spring. When an alternating voltage is
applied to the coil (2), a current flows and an attractive force is generated between the yoke (1)
and the movable core (3), and the movable core (3) spring (41, (41 ") repulsive force Overwhelms
and approaches York (11). When the instantaneous value of the voltage decreases and the
suction force decreases, the force of the spring (4) becomes fat and the movable core (3) moves
in the reverse direction. The tray mass (5) having the movable core (3) is structured to be
vibrated with the opposing mass (6) via the resonance spring (41, 41 '. The resonance spring (4)
connecting this tray mass (5) and the opposing mass (6), (The natural frequency of 41 'is close to
the power supply frequency (the tray mass (5) with a slight vibration force) Can be vibrated
greatly. FIG. 3 is a time chart of voltage when a commercial single phase alternating current is
used, FIG. 4 is a time chart of suction force, and FIG. 5 is a time chart of amplitude of vibration. If
the power source for exciting the coil uses a commercial single-phase alternating current as it is,
the suction force changes as shown in Fig. 4 and the level of O can be twice per cycle, so the
movable core (3) The frequency oscillates at twice the commercial frequency. Vibration in this
state causes the movable core (3) to vibrate without returning to the stationary position as shown
in FIG. However, a vibration having a frequency twice as high as the commercial frequency can
not give sufficient amplitude to the tray mass (5), so that no practical effect can be expected. In
order to ameliorate these problems, it is considered to control, for example, the waveform of a
commercial power supply, half-wave conduction angle control by combination of single-phase
and half-wave power supply by a rectifier or combined cycle etc. It has been devised that the
same vibration frequency is generated and the amplitude control is performed.
Figures 6, 7 and 8 show the attraction force and amplitude curves at half-wave voltage. In
addition to the above-described half-wave voltage control, there is one that is devised to generate
an oscillation frequency equivalent to the power supply frequency using a permanent magnet as
described in Japanese Patent Publication No. 43-19493. 9 and 10 (FIG. 10 is a principle view of
the configuration shown in FIG. 9). Is one example. This is a single E-shaped yoke (11) on the
fixed side and a U-shaped permanent magnet (12) on the movable core, facing each other so that
the salient pole parts are alternately inserted. By passing an alternating current to the exciting
coil (13) of (11), a frequency equivalent to the power supply frequency is generated. That is,
when the pole on the left side of the permanent magnet (12) sandwiching the center rod of the Eshaped yoke (11) is S in FIG. 10 and the pole on the right side is N, As in the above, the central
pole of the yoke (11) has an S pole and N poles on both sides. As a result, the permanent magnet
(12) moves in the left direction in the drawing by the magnetic attraction force and the repulsive
force. Next, at the negative half wave of the power supply voltage, the central rod of the yoke
(11) is excited to N + i, so the permanent magnet (12) moves to the right in the opposite
direction. Thus, the permanent magnet (I2) vibrates to the left and right at the same frequency as
the frequency of the power supply voltage. However, this method also has the following
problems. ■ To make the magnetic action between the permanent magnet (I2) and the yoke (II)
stronger, the air gap needs to be short (but then the moving stroke of the permanent magnet can
not be taken too long, and the resonance occurs at the start The vibration stroke becomes very
large when passing through the resonance points of the low-frequency eL number until the
vibration reaches it or until the frequency falls from its resonance frequency at the stop time, and
the yoke (11) and the permanent magnet become permanent. A so-called "striking" phenomenon
occurs in which the magnet (12) repeatedly collides with it, leading to breakage of the movable
part and deterioration of the spring. (2) In some cases, the center of the location where the
magnetic repulsion force is generated and the center of gravity of the driven body (I2) can not
always coincide with the center of the spring transmitting the vibration to the outside. Part of the
repulsive force acts on the resonant spring as unnecessary twisting force, making its design
difficult. SUMMARY OF THE INVENTION According to the present invention, the vibration stroke
can be made relatively large by solving the above-mentioned conventional problems, and the
center of the magnetic attraction / repulsion generation point and the center of gravity of the
vibrating member are resonant springs. It is an object of the present invention to provide an
electromagnetic vibrator that can improve the transmission of vibrational force to the tray mass
by aligning with the center of the.
The present invention has a cylindrical casing attached to a body to be vibrated, an inner wall of
the casing, at least two salient pole parts, and an opening formed between the salient pole parts
A U-shaped yoke mounted so as to point to the center of the casing, and a ring-shaped coil
member taken at the opening of the same U-shaped yoke so that the central axis of the casing
and the axial center coincide. An oscillating shaft supported on the axial center of the casing so
as to be capable of vibrating in the longitudinal direction with respect to the casing, and an outer
peripheral magnetic pole close to the salient pole portion of the yoke on the oscillating axis; The
present invention relates to an electromagnetic vibrator comprising permanent magnets disposed
and attached in a state in which the polarities of magnetic poles located between salient pole
portions and outside both salient pole portions are different. EXAMPLES The present invention
will be described based on the examples shown in FIG. 1I (longitudinal cross-sectional view) and
FIG. 12 (cross-sectional view taken along line 1-1 of FIG. 11). In this figure, (21) is a casing, (22)
is a U-shaped yoke (fixed iron core) arranged at a place where the circumference is divided into
four, and (23) is attached to be fitted into this yoke (22). A rectangular coil, (24) a vibrating shaft
made of a nonmagnetic material, (25) a disk spring which supports the vibrating shaft (24) to the
casing (2I) so as to be able to vibrate in the longitudinal direction 26) a ring-shaped permanent
magnet (vibrator) mounted on a vibration axis (24); (27a) to (27c) a yoke for forming a magnetic
circuit. (28) is a movable mass. The ring-shaped permanent magnet, which is a vibrator, is one of
the centers of the T-shaped cross section. It is arranged so that the inner side is the N pole (or S
pole) and the outer side is the S pole (or N pole) around the land iron (27a), and the
circumference of the center yoke (27a) is the N pole (or S pole) , And the outer yokes (27b) and
(27c) (7) are configured so as to have a south pole (or a north pole). In the case where a plurality
of permanent magnets between the yokes are formed, it is possible to obtain a vibrator having a
large output capacity by stacking the permanent magnets in the axial direction so that the
respective poles become salient poles. The U-shaped yoke (22) is arranged as a silicon steel sheet
stratified iron core so that the magnetic flux of the ring-shaped permanent magnet (26) which is
a vibration generating part can be fully utilized, in order to prevent eddy current loss generated
by AC power supply. . The disc spring (25) can also be made of a metal leaf spring material, but
in general, the peaks of the resonance point are smooth and fl? It is constructed in the form of a
P-shaped material, or a shear-type rubber spring formed by bonding a metal inner cylinder and
an outer cylinder with rubber. The U-shaped yoke (22) and the respective yokes (27a) to (27C)
are center yokes between the poles (22a) and (22b) of the yoke (22) as shown in FIG. The yokes
(27b) and (27c) on both sides are disposed outside the poles (22a) and (22b) of the yoke (22) so
that (27a) is positioned.
The movable mass (2B) is detachably or replaceably attached, and is configured to be capable of
attaching an appropriate mass according to the setting of the constant of the two-mass resonant
system. Now, when alternating current is applied to the coil (23), for example, one pole (22a) of
the yoke (22) becomes an N pole and the other pole (22b) becomes an S pole in a positive half
wave, as shown in FIG. As shown in the figure, the electromagnetic attraction force and the
reciprocation force act on the permanent magnet (26), and the vibration shaft (24) moves to the
right in the drawing against the supporting force of the disc spring (25) Do. Next, one of the
poles (22a) of the yoke (22) is inverted to the S pole, and the other pole (22b) is inverted to the N
pole in an AC negative half wave, and the oscillation axis (24) is on the drawing. The leftward
swing J force is received, so that the vibration axis (24) vibrates at the same frequency as the
power supply frequency. If the casing (21) of the electromagnetic vibrator having such a
configuration is attached to the body to be vibrated, the body to be vibrated vibrates by the
resonance action with the vibration axis (24). As described above, according to the present
invention, the following effects can be obtained. {Circle over (1)} It is possible to provide a
resonance type electromagnetic vibrator in which the 1 peristaltic stroke of the vibration axis is
relatively thick (and a "beat" phenomenon between two masses does not occur. (1) Since the
arrangement is such that the electromagnetic force acting on the ring-like permanent magnet is
concentrated on the vibration axis, the generated electromagnetic force and the vibration
transmission direction coincide with each other, thus the vibration transmission efficiency is
Brief description of the drawings
FIG. 1 is an explanatory view showing the outline of the configuration of a conventional
electromagnetic vibrator, FIG. 2 is an explanatory view showing the operation principle thereof,
and FIGS. 3 to 5 are vibrations when an AC power supply is given as an excitation voltage as it is
6 to 8 are waveform diagrams for explaining the temporal change of vibration generation when
the half wave rectified voltage is given as the excitation voltage, and FIG. 9 is another
conventional one. 10 is an explanatory view for explaining the operation principle, FIG. 11 is a
longitudinal sectional side view showing the configuration of the embodiment of the present
invention, and FIG. 12 is I of FIG. It is sectional drawing in -1 line.
(21): Casing (22): U-shaped yoke (fixed iron core) (23): Coil (24): I Φ ((25): Disc-shaped spring
(26): Ring-shaped permanent magnet (27a) ˜ (27c): Magnetic circuit forming yoke (28): Movable
mass patent applicant Murakami Seiki Co., Ltd. agent Hand-made profit (2 people) Fig. 11 Fig. 12