SU1207318A1 - Proportional electromagnet - Google Patents

Description

The invention relates to proportional electromagnets, which are the main control units of hydraulic automation elements with proportional control (valves, chokes, flow controllers, safety and pressure relief valves) used in systems for remotely controlling hydraulic hydrofication of machines and equipment (presses and other devices, including CNC).

The aim of the invention is to improve the accuracy by improving the linearity of the tractive characteristic at the working stroke of the core without significantly reducing the gain of the proportional electromagnet.

Fig. 1 shows a longitudinal section of the proposed Pr. Electrolyte; in fig. 2 - part of the core, facing the stop; Fig. 3 is a plot of the force of an electromagnet as a function of the stroke for a given value of the current in the excitation coil.

A proportional electromagnet consists of an external magnetic circuit 1, an excitation coil 2, an internal magnetic conductor located inside the excitation coil, which includes a sealed sleeve 3 welded from two magnetic conductive parts a and b and a third part from a non-magnetic material moving pole in the form of a cylindrical core 4 mounted in the cavity of the sleeve 3 with the potential of axial movement and a fixed pole, onto which the sleeve 3 is pressed into its part b, which, in conjunction with the support 5, forms a fixed floor The section of the part b of the hermetic sleeve 3, which extends beyond the core, is a ferromagnetic shunt of the fixed pole. A flange 6 with a sealing ring 7 is installed on the part of the sleeve protruding from the external magnetic core.

Parts a, b, c of the sleeve 3 are made with flat ends, which are aligned with each other, for example by diffusion welding with heating in vacuum, with the exception of mixing magnetic and non-magnetic materials.

On the inner surface of the liner from the side of the flange 6 is made boring

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The casing in which the sleeve 8 is installed, the anchor 4 of a cylindrical shape, has a through bore in which the guide rod 9 is rigidly mounted. In the sleeve 3, the bore 4 is installed with a gap and guided when moved by the guide rod 9 in the sleeves 8 and 10.

At the end of the bark 4 facing the fixed support, there is a peripheral annular groove 11 of the trapezoidal cross section, which has a peripheral conical surface A, forming in the longitudinal section of the core 4 an acute angle about its outer cylindrical surface B.

The annular groove forms on the cortex two forming ferromagnetic shunt (Fig. 2). The first of the variable section shunts is formed by a portion of the core located between the annular groove 11 and the outer cylindrical surface B of the core 4. The second shunt is formed by the end portion of the core encircled by the annular groove 11.

The cross-sectional area of the first shunt of the core increases with distance from the end B of the core 4,

The annular edge 12 at the end of the core is bounded by the outer cylindrical surface B and the conical surface A.

 The outer end surface of the core 4, covered by the annular groove 11, as well as the annular edge 12 may lie in the same plane. The optimum diameter d of the core end bounded by an annular groove 11 (i.e., the width of the groove) is chosen experimentally in order to obtain an optimal proportionality value for a particular size of the electromagnet.

A spacer washer 13 of non-magnetic material is installed between the stop 5 and the core 4.

The cavity 14, in which the bark is placed, is hermetically separated from the external magnetic circuit 1 and the exciter coils 2 by means of a sealed welded sleeve 3, which is pressed onto the support 5 and sealed in the blind flange 6 by a sealing ring 7.

The proposed design of the proportional electromagnet provides for diffusion welding of the liner parts only along the plane of the ends

details. During diffusion welding, tight contact of the mating surfaces and welding of the liner parts along the flat ends of the parts is more technological than welding the liner parts with conical end surfaces, since it is technologically easier to achieve tight contact on the flat surfaces than conic.

The flat ends of the parts to be welded to the liner are made on universal equipment without the use of special expensive tooling necessary for the manufacture and fitting of the mating conical end surfaces of the welded liner parts.

The device works as follows.

When current flows in excitation coil 2, measles 4 is attracted. to the stop 5, thereby developing a force proportional to the magnitude of the current in the excitation coil, which varies on the working stroke of the core at a constant current (see graph, Fig. 3, curve 15). This is achieved due to the presence at the end of the core 4 of two ferromagnetic shunts formed by the ring of the core stroke (Fig. 3, crimped groove 11.va17), reducing the electromagnet force on the core working stroke and the current sensitivity of the hydroapparatus.

Thus, by obtaining an optimal characteristic of a proportional electromagnet, the stability of the operation of the elements of the hydraulic automation and the sensitivity of their current control, in which the proposed electromagnet is used as the control step, is increased.

At the beginning of the working stroke of the core, the force developed by the electromagnet is mainly due to the interaction of the 35 ferromagnetic shunt of the variable cross-section core with the ferromagnetic shunt of the stationary pole, while the effect of the second shunt of the core on the electromagnet force is negligible. before

As the cor. to stop the first ferromagnetic shunt of the alternating core

the cross section and the ferromagnetic shunt of the stationary pole, while the tractive force of the electromagnet varies slightly, since the second ferromagnetic shunt of the core, covered by the annular groove 11 (see Fig. 3, curve 15), interacts with the stop face.

Thus, the thrust force of the electromagnet at the working stroke of the core is not significantly reduced.

The proposed design allows, by changing the diameter of the front part of the bore, bounded by the annular groove 11, to obtain the optimum shape of the characteristic when the core 4 is positioned closer to the stop 5.

As the diameter d increases from the optimal value, the magnetic interaction of the end B of the core with the end K of the stop at the end of the working stroke of the core increases (Fig. 3, curve 16), worsening the linearity of the characteristic and reducing the stability of the hydroapparatus controlled an electromagnet. When the diameter d decreases from the optimal value, the magnetic interaction of the end B of the core with the end K of the stop 5 at the end of the working

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Compiled by B. Gundarov Editor L. Narodna Tehred M. Khodanych Proofreader E. Roshko

Order 633 / 1-. Circulation 699 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

1 (BGN,

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Claims (1)

A PROPORTIONAL ELECTROMAGNET containing an external magnetic circuit, an excitation coil, a non-magnetic sleeve, a magnetic circuit located inside the excitation coil, including a fixed pole with a saturable ferromagnetic ring shunt and a cylindrical armature mounted with the possibility of axial movement, the non-magnetic sleeve sealing the armature and the coil from the coil external magnetic circuit, distinguished by the fact that, in order to improve the accuracy of work by improving the linearity of the traction characteristic, n and the end of the anchor facing the fixed pole has an annular groove of a trapezoidal section, so that a saturable ferromagnetic ring shunt is formed at the anchor in the form of two elements, one of which has a variable cross section, increasing with distance from the end of the anchor, and is formed by the part of the anchor between the peripheral the lateral surface of the annular groove and the outer cylindrical surface of the anchor, and the other shunt element is formed by the other lateral surface of the annular groove and the end surface of the anchor.