JPS58119612A - Electromagnet device - Google Patents

Abstract

PURPOSE:To prevent generation of excessive attracting force of the electromagnet when attraction is completed by a method wherein a penetrating hole, a groove, etc., is provided in a movable core to make the width at the middle part to be narrowed substantially. CONSTITUTION:The penetrating hole 10 having the hole diameter D is formed at the middle part of the movable core 5 to make width at the middle part to be narrowed (B-D) substantially, and accordingly the quantity of magnetic flux is limited when attraction is completed, and action of excessive attracting force to the movable core 5 is prevented. By providing the penetrating hole 10, reduction of increase of magnetic flux according to approach of the movable core 5 to a core 3 up to the neighborhood of the saturated value can be attained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electromagnetic device designed to reduce excessive suction force upon completion of suction.

Generally, this type of electromagnet device is formed into a hollow shape as shown in Fig. 1 C) and Φ), and has flanges 1 & 1 on the outer peripheral surface of both ends.
A coil spool 1 integrally having a coil spool 1, an excitation coil 2 wound around the outer circumferential surface of the coil spool 1, an iron core 3 disposed in the hollow part of the coil spool 1, and a magnetic circuit together with the iron core 3. The yoke 4 has an abbreviated shape, and the base of the yoke 4 is rotatably supported at the upper end of the yoke 4 by suitable bearing means, and is provided with a restoring habit in the direction of always moving away from the iron core 3 by a spring 6. The movable iron core 5 is attracted to the iron core 3 against the spring 6 when the excitation coil 2 is energized. In this case, when the movable iron core 5 rotates under attraction, the force of the spring 6 changes approximately linearly as shown in Figure 2, while the attraction force F of the coil 2 changes as the square of the distance l. Since it is inversely proportional, it increases in a curved manner as the movable core 5 rotates, and the suction force y reaches its maximum when suction is completed, causing various problems.

For example, when incorporated into a DC electromagnetic counter,
When the suction of the movable core 5 is completed, an excessive force y (line part f14 in Fig. i'2) is applied to the movable core 5, so the skeleton core 5 is distorted, the gap G between the core 3 and the movable core 5 becomes smaller, and the electric Even after the pulses are interrupted, the residual magnetic flux increases, delaying the recovery operation of the movable core 5 (preventing the speed-up of the counter 1. Also, when the movable core 5 is attracted, the core 5 trembles and excessive force is applied to the bearing part 7 of the moving core 5), reducing the performance of the counter.

The present invention has been made in view of the above-mentioned points, and by providing through holes, grooves, etc. in the movable core and substantially narrowing the midway width of the core, the magnetic flux at the time of completion of suction is reduced. The present invention provides an electromagnet system that solves the above problem by demagnetizing the magnet to a state close to saturation.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

FIG. 3 is a partially cutaway plan view showing an embodiment of the electromagnet device according to the present invention. In the figure, the movable iron core 5 has an appropriate diameter ti in the middle. This is different from the conventional device shown in FIG. 1 in that the width of the cylindrical circumference is substantially narrowed in the middle of the front P by forming t10, thereby limiting the amount of magnetic flux when the suction is completed, This is to prevent excessive suction force from acting on the movable iron core 5. Note that the same reference numerals as in FIG. 1 indicate the same structural members, and therefore the description thereof will be omitted.

Therefore, considering the amount of magnetic saturation, the magnetic flux Φ passing through the magnetic circuit is Φ= 1 p *... (11
(L: u is ampere turns of coil 2, p is permeance).

Since U is determined by the product of the current and the number of turns, it can be expressed as a constant, and p is the permeance Pg on the X-Y axis of the 30-circular surface of the iron core, and the permeance Ph at the fulcrum sK of the movable iron core S (fflLph=pr+P@ ) and is expressed as .

where μ is the magnetic permeability, t is the air gap between the iron core 3 and the movable iron core 5, S is the cross-sectional area of the end face of the iron core 3, k is a constant, θ is the rotation angle of the movable iron core 5, B is the width of the movable iron core 5, xo is the range where the air gap is considered to be poor in the contact area between the movable core 5 and the plate 4, t is the extreme thickness of the movable core 5, α is a constant, and b is the through hole 1 of the movable core 5
0 is formed and is the width (It-D) at the middle part (however, regarding t, 0° xo, and t, see II in Fig. 1).

As is clear from the above (Formula 21), as PijPn increases, in other words, as the intermediate width of the movable iron core 5 increases. Also, since the magnetic flux - is proportional to P, it is influenced by b, assuming that the magnetic circuit is not extremely saturated.

Therefore, by making use of this fact and providing the through hole 10, it is possible to reduce the increase in magnetic flux caused by the proximity of the movable core 5 to the core 3 to around the saturation value, which is not possible in the conventional method. The suction force curve can be made gentler.

In this case, especially for the influence on the permeance pe, that is, for a certain magnetic flux of 0 or more, it is necessary to form a saturated part tube by the middle width of the movable iron core 5, and also to move the through hole 1o11-x axis direction to the outside of the iron core 3. If it is brought close to the radial end, it will have an effect on the permeance Pg, and by changing the retreat gl, a desired suction curve line can be obtained.

Figure 4 (1) to (,) are the movable iron core 5 and transparent? Figure 5 shows the current waveform depending on the positional relationship of tlo. It is a figure which shows the electric ff11I type when using the conventional movable iron core which does not have it.

As is clear from these figures, the current waveform in Figure 4) is the gentlest and has the least amount of pounding, while the waveform of the conventional device has a noticeable pounding in the middle. This pound is generated because the diagnostic force suddenly becomes stronger when suction is completed, and the movable iron core 5 comes into contact with the iron core 3.

In addition, in the upper F embodiment, the intermediate width bVK of the movable iron core 5
Although a case has been described in which a through hole 110 is provided as a means for substantially narrowing the width, the present invention is not limited to this. Of course, it may be an extending long groove or a combination of a round hole and a long groove.

As explained above, the electromagnet device according to the present invention is designed to reduce the saturation value of the magnetic flux by providing a through hole etc. in the middle of the movable core and narrowing the path through which the magnetic flux passes. The generation of excessive suction force in the tube can be prevented. Therefore, there is less deformation of the movable core, generation of residual magnetism, etc., allowing for good suction and recovery operations, and less damage to the bearing part, improving the performance of the device itself and the lateral durability of the electromagnetic tube. Suitable for use in devices such as counters. Furthermore, since the structure is simplified and the intermediate width of the movable iron core can be easily narrowed by press working, it can be manufactured at low cost, and the effect is very large.

[Brief explanation of the drawing]

Figures 1) and 2) are plan and side sectional views showing a conventional electromagnet device, Figure 2 is a diagram showing the force of a spring and the attractive force of a coil, and Figure 3 is an embodiment of an electromagnet device according to the present invention. A partially cutaway plan view showing an example, fIg4 Figures (1) to (@) are diagrams showing current waveforms depending on the positional relationship between the movable core and the through hole, and Figure 5 shows a conventional movable core without a through hole. FIG. 3 is a diagram showing a current waveform when 111...Coil spool, 2...1mm cocoil 3...Iron core, 4...Yoke, sll...Movable iron core, 6...Coil spring, 1@...Bearing means (
Department). Patent applicant: Tamura Electric Manufacturing Co., Ltd. Agent: Masaki Yamakawa (and one other person)

Claims (1)

[Claims] A nine-coil mepool around which the coil is wound, an iron core disposed in the hollow part of this coil spool, a yoke that is integrated or integrated with this iron core to form a magnetic circuit, and one end of which is rotatably attached to this yoke. The movable iron core is pivotally mounted and pulled by the iron core when the coil is energized, and the intermediate width t* of the movable iron core is qualitatively narrowed to lower the saturation value of the amount of magnetism. An electromagnetic device with a % characteristic.