CN101345167A - Method and apparatus for improving dynamic response ability of coil magnetic field to moving iron core - Google Patents

Abstract

The invention relates to a method and a device used for improving dynamic reaction capability of coil magnetic field on a movable iron core, which is characterized in that: in a normal permanent magnetic mechanism, the contact surface of the end cover at one side or two sides and the movable iron core is arranged to be a non-plane curved plane type; by improving the axial magnetic field grads, the dynamic driving force of the coil magnetic field on the movable iron core is improved, thus improving the dynamic reaction speed of the permanent magnetic mechanism on the single-side or dual-side of the movable iron core further. The method and the device of the invention can carry out identical or different structural design on the two contact surfaces according to different usage situation and different usage requirement, generate identical or different dynamic motion speed, can be widely applied to the vacuum circuit breakers in power industries, and are applicable to all situations which drives the iron core to reciprocate by improving the permanent magnetic mechanism of the axial magnetic field grads and is provided with high-static retaining force and quick dynamic reaction capability simultaneously.

Description

A kind of method and device that improves coil magnetic field to moving iron core dynamic response ability

Technical field

The present invention relates to a kind of permanent magnet mechanism, particularly about a kind of method and device that improves coil magnetic field to moving iron core dynamic response ability.

Background technology

The mechanism that has the axially reciprocating function at present is widely used in various fields such as power switchgear, machine-building, medicine equipment, engineering machinery, textile machine.Such mechanism normally utilizes rotatablely moving of driving element to convert that straight-line mode realizes to, realizes that the driving element of this process generally adopts spring mechanism, hydraulic mechanism, servomechanism etc.But there is following problem in it: 1, spring mechanism has shortcomings such as complex structure, volume is big, amount of parts is many, failure rate is high, reliability is low, this be because each spring mechanism remove standard component also need be up to the parts more than 120, and also have many mechanical lock buckle devices that are mutually related.2, hydraulic mechanism not only has numerous pipelines and control valve, and leak of liquid is the difficult problem that the limiting mechanism reliability improves, and extremely is difficult to perfect the solution.3, servomechanism needs complicated control system and controls, and is with high costs, is difficult to popularize.Therefore, along with the appearance of novel high-performance permanent magnetic material, people have developed the mechanism that confining force is provided with permanent magnet in recent years, are called for short permanent magnet mechanism, and disclosed patent has: Chinese patent CN 1202714A, CN 2337668Y, CN1416151A etc.

As shown in Figure 1, be the actuating force of permanent magnet mechanism and spring mechanism and the comparison diagram of travel relationships, wherein a represents the combined floodgate characteristic curve of vacuum interrupter requirement, and b represents the characteristic curve that spring operating mechanism provides when closing a floodgate, and c represents the characteristic curve that permanent magnet mechanism provides when closing a floodgate.This shows, compare that permanent magnet mechanism has excellent mechanical property, electrical characteristic, suitable closing speed and opening velocity, long useful life and higher reliability with spring mechanism.Therefore, permanent magnet mechanism more can meet the high reliability of current social switching devices, the overall development trend and the requirement of non-maintaining, intelligent, miniaturization, and permanent magnet mechanism just is being widely used in the middle pressure vacuum circuit-breaker in the electric power system at present.Simultaneously State Grid Corporation of China also clearly with permanent-magnet manipulating mechanism, miniaturization, non-maintaining vacuum technique, classifies the new technology application direction of distribution and electricity consumption as.

As shown in Figure 2, it is permanent magnet mechanism schematic diagram in the prior art, its course of work is: when closing coil 10 started, moving iron core 11 drove drive rod 12 together to left movement under the effect of closing coil 10, until moving iron core 11 with till combined floodgate end cap 13 contacts; Electric current in the closing coil 10 stops at this moment, and moving iron core 11 is kept by permanent magnet 14 and outer flux sleeve 15, combined floodgate end cap 13 and interior magnetic guiding loop 16 formed magnetostatic loops with combined floodgate end cap 13 contacted states, thus the formation "on" position.Similarly, when switching winding 17 started, moving iron core 11 overcame combined floodgate static immobilization confining force and drives drive rod 12 and move right together under the effect of switching winding 17, until moving iron core 11 with till separating brake end cap 18 contacts; Electric current in the switching winding 17 stops at this moment, and moving iron core 11 is kept by permanent magnet 14 and outer flux sleeve 15, separating brake end cap 18 and interior magnetic guiding loop 16 formed magnetostatic loops with separating brake end cap 18 contacted states, thus the formation gate-dividing state.Describe as can be known by the above-mentioned course of work to permanent magnet mechanism, the dynamic response ability of moving iron core is to pass through relational expression: F ₀=F _z-F _gShow, wherein F _zThe expression coil magnetic field is to the dynamic driving power of moving iron core, F _gThe static immobilization confining force of the moving iron core of expression, F ₀The expression coil is to the net effort of moving iron core.That is to say F ₀Determining the dynamic response ability of moving iron core, F ₀Big more, dynamic response ability is just big more, otherwise just more little.

Yet, well-known, particularly defeated, the power transformation field of power industry such as power switch in, as the permanent magnet mechanism of axially reciprocating, not only require to have very high static confining force, also require to have enough fast dynamic response ability, that is to say F _gAnd F ₀All want big.Therefore feasible way is exactly to improve the dynamic driving power F of coil magnetic field to moving iron core _z, and can't provide satisfied in this respect in the prior art, and in the prior art, if the static immobilization confining force of moving iron core is high more, then coil is just poor more to the net effort of moving iron core, and the dynamic response ability of moving iron core is just poor more; On the contrary, sufficiently high dynamic response ability is arranged, just have to sacrifice the static immobilization confining force of moving iron core for guaranteeing moving iron core.Therefore, design a kind of high static immobilization confining force that both had, the axial high-gradient magnetic field permanent magnet mechanism that has fast dynamic response ability again is a new research topic.

Summary of the invention

At the problems referred to above, the purpose of this invention is to provide a kind ofly under the constant situation of material, volume and the coil magnetic field intensity of moving iron core, can significantly improve method and the device of coil magnetic field to moving iron core dynamic response ability.

For achieving the above object, the present invention takes following technical scheme: a kind of method that improves coil magnetic field to moving iron core dynamic response ability, it is in conventional permanent magnet mechanism, the contact-making surface of moving iron core and one or both sides end cap is set to the mode of on-plane surface curved surface, by improving the axial magnetic field gradient of permanent magnet mechanism, improve coil magnetic field to moving iron core dynamic driving power, and then improve the dynamic response speed of the one-sided or bilateral movement of moving iron core in the permanent magnet mechanism.

The contact-making surface of a described moving iron core and a side end cap is arranged to the plane, be arranged to the on-plane surface curved surface with the contact-making surface of opposite side end cap, thereby strengthen coil to the dynamic response speed of moving iron core to on-plane surface curved surface one side, the dynamic response speed of this side is higher than the dynamic response speed of plane one side.

Simultaneously the contact-making surface of described moving iron core and both sides end cap is arranged to the on-plane surface curved surface, strengthens the dynamic response speed of moving iron core to both sides.

The curvature of a described moving iron core and a side contacts face is greater than the curvature of opposite side contact-making surface, makes the dynamic response speed of a side be higher than the dynamic response speed of opposite side.

The curvature of a described moving iron core and a side contacts face equals the curvature of opposite side contact-making surface, makes both sides dynamic response speed identical.

A kind of device of realizing the raising coil magnetic field of said method to moving iron core dynamic response ability, it comprises that one is fixed on the moving iron core on the drive rod, magnetic guiding loop in the sliding sleeve one of described moving iron core outside, the outer surface of magnetic guiding loop fixedly installs an annular permanent magnet in described, flux sleeve outside the outer surface of described annular permanent magnet fixedly connected, the both sides of magnetic guiding loop and annular permanent magnet in described, being provided with one respectively fixedlys connected with described outer flux sleeve, the closing coil and the switching winding that are slidingly connected with described moving iron core, the arranged outside one of described closing coil wore described drive rod and with described outside the fixing all-in-one-piece combined floodgate end cap of flux sleeve, the arranged outside one of described switching winding wore described drive rod and with described outside the fixing all-in-one-piece separating brake end cap of flux sleeve, between described combined floodgate end cap and separating brake end cap, leave the space that moving iron core moves, it is characterized in that: in the contact-making surface of described moving iron core and described combined floodgate end cap or separating brake end cap, having a side contacts face at least is the on-plane surface curved surface.

The curve form of described contact-making surface be boss shape, taper shape, circular arc, semicircle, polygon, V-arrangement, in a zigzag, trapezoidal, zigzag and parabola shaped in the combination of one or more shapes.

The contact-making surface of a described moving iron core and a side end cap is the plane, with the contact-making surface of opposite side end cap be the on-plane surface curved surface.

The contact-making surface of described moving iron core and both sides end cap is identical shaped on-plane surface curved surface.

The contact-making surface of described moving iron core and both sides end cap is the on-plane surface curved surface, and the curvature of a side contacts face shape greater than with the curvature of opposite side contact-making surface shape.

The present invention is owing to take above technical scheme, it has the following advantages: 1, the present invention uses electromagnetism and mechanics principle to analyze the static confining force of permanent magnet mechanism and the Controlling Source of dynamic response power, by changing the contact-making surface shape between moving iron core and the one or both sides end cap, change the gradient of axial magnetic field, and then the dynamic response ability of raising permanent magnet mechanism, the simple science of its structural principle has innovation and practical value.2, the present invention seems to be simple to the improvement of permanent magnet mechanism structure, but, compared with the prior art the present invention can significantly improve the dynamic driving power of coil magnetic field to moving iron core under the constant situation of material, volume and the coil magnetic field intensity of moving iron core, its beneficial effect is very remarkable.3, the present invention can carry out identical and different curved-surface structure designs to two contact-making surfaces, and implement convenience, wide application, good economy performance according to different use occasions and different instructions for uses.The present invention can be widely used in the vacuum circuit-breaker of power industry.

Description of drawings

Fig. 1 is the actuating force of prior art permanent magnet mechanism and spring mechanism and the comparison diagram of travel relationships

Fig. 2 is a prior art permanent magnet mechanism schematic diagram

Magnetic line of force formation figure when Fig. 3 is that iron core and end cap are plane contact

Fig. 4 is that iron core and end cap are the magnetic line of force formation figure of curved surface when contacting

Fig. 5～7th, an end is an on-plane surface curved surface schematic diagram in the contact-making surface of moving iron core of the present invention and two end cap

Fig. 8～10th, both-end is identical on-plane surface curved surface schematic diagram in the contact-making surface of the moving iron core of the present invention and two end cap

Figure 11～13rd, both-end is an on-plane surface curved surface schematic diagram inequality in the contact-making surface of moving iron core of the present invention and two end cap

Embodiment

Below in conjunction with drawings and Examples the present invention is described in detail.

The applicant in doing the permanent magnet mechanism of axially reciprocating, moves the static confining force F between iron core and the end cap by discovering _gWith the dynamic driving power F of coil magnetic field to moving iron core _zOn magnetics mechanism, be different.Coil magnetic field is to the dynamic driving power F of moving iron core _zBy the energy equation analysis in magnetic field, the utilization principle of virtual work is derived as follows:

Suppose that volume is V _mMagnetisable material, under the effect of magnetic field H, in axial direction moved the dz distance, then the magnetic field energy in its volume range changes and can be provided by the magnetic field energy equation:

$\mathrm{\Δ}{W}_m=\frac{1}{2}\mathrm{\μ}{H}^2{V}_m-\frac{1}{2}{\mathrm{\μ}}_0{H}^2{V}_m---\left(1\right)$

Here, μ is the magnetic permeability of magnetisable material, μ ₀Be permeability of vacuum.With the known relation formula:

$\mathrm{\μ}={\mathrm{\μ}}_0(1+\frac{M}{H})---\left(2\right)$

$={\mathrm{\μ}}_0(1+\mathrm{\χ})$

Substitution formula (1) has:

$\mathrm{\Δ}{W}_m=\frac{1}{2}{\mathrm{\μ}}_0\mathrm{\χ}{H}^2{V}_m---\left(3\right)$

Here, x is the magnetic susceptibility of magnetisable material, because V _mHave certain space size, usually, be the function in space at this magnetisable material volume range internal magnetic field intensity H and magnetic susceptibility x, so external magnetic field active force vertically can be expressed as:

$F_z=\frac{\∂\mathrm{\Δ}{W}_m}{\∂z}$

$={\mathrm{\&mu;}}_0\mathrm{\&chi;}{V}_{m}H\frac{\&PartialD;H}{\&PartialD;z}+\frac{{\mathrm{\&mu;}}_0{V}_m}{2}{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="A20081010605200121.png,A20081010605200123.png"\; state="\{\{state\}\}">H</figure-callout>}}^2\frac{\&PartialD;\mathrm{\&chi;}}{\&PartialD;z}---\left(4\right)$

In the formula,

Be magnetic field gradient, when the magnetic susceptibility of material was constant, second was zero in the formula.This shows that any magnetisable material suffered net effort in uniform magnetic field is zero.Under normal conditions, in the formula (4) first depended on to the active force of magnetisable material in magnetic field, that is:

$F_z={\mathrm{\&mu;}}_0\mathrm{\&chi;}{V}_{m}H\frac{\&PartialD;H}{\&PartialD;z}---\left(5\right)$

Its direction is pointed to the direction that rate of change of magnetic increases.

And the static confining force between moving iron core and the end cap is permanent magnetic field Maxwell (maxwell) tension force on medium interface, and known formula is:

$F_g=\frac{1}{2}{\mathrm{\&mu;}}_0{H}_g^2{S}_m---\left(6\right)$

Here, μ ₀Be permeability of vacuum, H _gBe the air-gap field intensity between moving iron core and the end cap, S _mBe the contact area between moving iron core and the end cap.

This shows, under the constant situation of material, volume and the coil magnetic field intensity of moving iron core, the gradient by improving coil magnetic field intensity-

Just can significantly improve the dynamic driving power of coil magnetic field, thereby improve the net effort F of coil moving iron core to moving iron core ₀Though when the contact-making surface of moving iron core and end cap was flat state, also there was gradient in coil magnetic field, its Grad is less, magnetic field to the dynamic driving power of moving iron core a little less than.According to magnetic line of force refraction principle as can be known, on the soft iron border of high magnetic permeability, nearly all magnetic line of force all tends at air one side vertical boundary.Therefore, when the field of conjugate action that moves iron core and end cap was designed to curved surface, at moving iron core near surface, the wide-angle distortion can take place in the magnetic line of force, and the inhomogeneities of magnetic field intensity enlarges markedly, thereby has increased substantially the magnetic field gradient of moving iron core near surface.As shown in Figure 3, when the field of conjugate action of moving iron core 11 and combined floodgate end cap 13 was flat state, the magnetic line of force a that closing coil 10 is produced was close to and passes moving iron core 11 surfaces equably, and the magnetic field of moving iron core 11 near surfaces is more even, Grad is less, magnetic field to the dynamic driving power of moving iron core 11 a little less than; And when the field of conjugate action of moving iron core 11 and combined floodgate end cap 13 is curved surface (as shown in Figure 4), at moving iron core 11 near surfaces, the wide-angle distortion takes place in magnetic line of force a, the inhomogeneities in magnetic field enlarges markedly, thereby increased substantially the magnetic field gradient of moving iron core 11 near surfaces, by above-mentioned formula (4) as can be known, because field gradients strengthens, under all constant situation of material, volume and the coil magnetic field intensity of moving iron core, can significantly improve the dynamic driving power of coil magnetic field to moving iron core.

According to above analysis, the invention provides a kind of permanent magnet mechanism with axial high-gradient magnetic field, it is on the basis of existing permanent magnet mechanism, and the contact-making surface that moves two end caps of iron core and both sides is designed to one or both sides on-plane surface curved surface.This on-plane surface curved surface can be boss shape, taper shape, semicircle, circular arc, polygon, V-arrangement, in a zigzag, a kind of in trapezoidal, the zigzag, shape such as parabola shaped, also can be the above combination of above-mentioned a kind of shape.Specific embodiment is as follows:

Embodiment one

As shown in Figure 5, present embodiment comprises that one is fixed on the moving iron core 2 on the drive rod 1, slip is provided with magnetic guiding loop 3 in moving iron core 2 outsides, fixed outside at interior magnetic guiding loop 3 is provided with an annular permanent magnet 4, fixed outside at annular permanent magnet 4 connects flux sleeve 5 outside, in the both sides of interior magnetic guiding loop 3 and annular permanent magnet 4, be provided with one respectively and fixedly connected with outer flux sleeve 5 and be slidingly arranged in closing coil 6 and switching winding 7 on the moving iron core 2.The arranged outside one of closing coil 6 wear overdrive bar 1 and with the fixing all-in-one-piece combined floodgate end cap 8 of outer flux sleeve 5, the arranged outside one of switching winding 7 wear overdrive bar 1 and with the fixing all-in-one-piece separating brake end cap 9 of outer flux sleeve 5, between combined floodgate end cap 8 and separating brake end cap 9, leave moving iron core 2 and move and close a floodgate and the space of separating brake.Moving iron core 2 is conventional plane contact with the contact-making surface of combined floodgate end cap 8, and the contact-making surface between moving iron core 2 and the separating brake end cap 9 is the taper type curved surface.Like this, when switching winding 7 started, formed magnetic field had higher magnetic field gradient, and then moving iron core 2 is formed bigger dynamic driving power, made iron core get off quickly and close a floodgate magnetostatic absorption affinity between the end cap 8, moved to separating brake end cap 9 directions.By contrast, when closing coil 6 started, moving iron core 2 was lower with the formed magnetic field gradient of flat contact surface between the separating brake end cap 9, and the suffered dynamic driving power of moving iron core 2 is less, and it is also corresponding lower to the motor reaction speed of combined floodgate end cap 8 to move iron core 2.

Embodiment two

As Fig. 6, shown in Figure 7, present embodiment is similar to the above embodiments, be the unilateral surface shape, although curve form is different, but near the magnetic field gradient the contact-making surface all can have greatly changed, and when switching winding 7 starts, all can form higher dynamic driving power to moving iron core 2, make iron core 2 break away from and close a floodgate magnetostatic absorption affinity between the end cap 8, accelerate to the reaction speed of separating brake end cap 9 motions.

Above-mentioned two embodiment are that the iron core 2 and the contact-making surface of two end cap 8,9 are unilateral surface contacting structure form, and such structure is suitable for movement velocity a low reciprocating motion occasion of the high direction of direction, wherein, has a lateral movement speed of curved surface fast.

Embodiment three

Shown in Fig. 8～10, the contact-making surface that present embodiment has been enumerated moving iron core 2 and two end cap 8,9 is the nilarteral surface contact structures, and such as the contact surface (only as example) that all is taper type, as Fig. 8, shown in Figure 9, two contact surfaces are symmetrically arranged; As shown in figure 10, two contact surfaces are equidirectional settings.This several setting can reach the purpose that improves bilateral contact-making surface magnetic field gradient equally.When closing coil 6 or switching winding 7 startups, formed magnetic field all has higher axial magnetic field gradient, and is also bigger to the dynamic driving power of moving iron core 2, and such structure is suitable for the movement velocity of both direction and all wants high and identical reciprocating motion occasion.

Embodiment four

Shown in Figure 11～13, the contact-making surface that present embodiment has been enumerated moving iron core 2 and two end cap 8,9 is the various multi-form of bilateral contact surface structure, but contact both sides curve form difference.Such structure and embodiment one are similar, are suitable for the motor reaction speed reciprocating motion occasion inequality of both direction.But compare with embodiment one, difference is: contact-making surface is that will to be higher than contact-making surface be the acceleration that is produced in the structure on plane for the acceleration that produced in the structure of on-plane surface curved surface, the curvature of contact surface is big more, and magnetic field intensity gradient is big more, and formed dynamic driving power is just big more.

In the various embodiments described above, permanent magnet 4 can use any known permanent magnetic material to make, such as the sintered body or the cohesive body that are neodymium-iron-boron or samarium-cobalt or ferrite or alnico alloy, here selecting the trade mark for use is SANMAG-N39SH, the remanent magnetism Br=12.5kGs of material, the permanent magnetic material of coercivity H b=12.0kOe; The radial section of permanent magnet 4 can be an annular, also can be arranged to other shape according to designing requirement, for example polygon, rectangle, ellipse etc.Permanent magnet 4 can be single ring body, also can be that to have same magnetic with polylith assembled apart from watt shape fritter of direction, can further reduce the cost of permanent magnetic material like this, enlarges the scope of using.

In the various embodiments described above, outer flux sleeve 5, interior magnetic guiding loop 3, moving iron core 2, combined floodgate end cap 8 and separating brake end cap 9 can use mild steel or high permeability materials such as pure iron or silicon steel or permalloy or non-crystaline amorphous metal to make.

In the various embodiments described above, the stainless steel of the non-magnetic conduction of drive rod 1 use or copper alloy or aluminium alloy or organic material are made.Drive rod 1 can adopt with moving iron core 2 and be threaded, sell be connected, riveted joint, welding manner or with the combination of one or more modes of upper type.

In the various embodiments described above, can be in the periphery of each assembly, the method that employing is electroplated, applies, flooded forms layer of metal or non-metallic film, plays effect anticorrosion, that lubricate and improve outward appearance.

Claims (10)

1, a kind of method that improves coil magnetic field to moving iron core dynamic response ability, it is in conventional permanent magnet mechanism, the contact-making surface of moving iron core and one or both sides end cap is set to the mode of on-plane surface curved surface, by improving the axial magnetic field gradient of permanent magnet mechanism, improve coil magnetic field to moving iron core dynamic driving power, and then improve the dynamic response speed of the one-sided or bilateral movement of moving iron core in the permanent magnet mechanism.

2, a kind of method that improves coil magnetic field to moving iron core dynamic response ability as claimed in claim 1, it is characterized in that: the contact-making surface of a described moving iron core and a side end cap is arranged to the plane, be arranged to the on-plane surface curved surface with the contact-making surface of opposite side end cap, thereby strengthen coil to the dynamic response speed of moving iron core to on-plane surface curved surface one side, the dynamic response speed of this side is higher than the dynamic response speed of plane one side.

3, a kind of method that improves coil magnetic field to moving iron core dynamic response ability as claimed in claim 1 is characterized in that: simultaneously the contact-making surface of described moving iron core and both sides end cap is arranged to the on-plane surface curved surface, strengthens the dynamic response speed of moving iron core to both sides.

4, a kind of method that improves coil magnetic field to moving iron core dynamic response ability as claimed in claim 3, it is characterized in that: the curvature of a described moving iron core and a side contacts face is greater than the curvature of opposite side contact-making surface, makes the dynamic response speed of a side be higher than the dynamic response speed of opposite side.

5, a kind of method that improves coil magnetic field to moving iron core dynamic response ability as claimed in claim 3, it is characterized in that: the curvature of a described moving iron core and a side contacts face equals the curvature of opposite side contact-making surface, makes both sides dynamic response speed identical.

6, a kind of realization as the raising coil magnetic field of method as described in the claim 1～5 device to moving iron core dynamic response ability, it comprises that one is fixed on the moving iron core on the drive rod, magnetic guiding loop in the sliding sleeve one of described moving iron core outside, the outer surface of magnetic guiding loop fixedly installs an annular permanent magnet in described, flux sleeve outside the outer surface of described annular permanent magnet fixedly connected, the both sides of magnetic guiding loop and annular permanent magnet in described, being provided with one respectively fixedlys connected with described outer flux sleeve, the closing coil and the switching winding that are slidingly connected with described moving iron core, the arranged outside one of described closing coil wore described drive rod and with described outside the fixing all-in-one-piece combined floodgate end cap of flux sleeve, the arranged outside one of described switching winding wore described drive rod and with described outside the fixing all-in-one-piece separating brake end cap of flux sleeve, between described combined floodgate end cap and separating brake end cap, leave the space that moving iron core moves, it is characterized in that: in the contact-making surface of described moving iron core and described combined floodgate end cap or separating brake end cap, having a side contacts face at least is the on-plane surface curved surface.

7, a kind of device that improves coil magnetic field to moving iron core dynamic response ability as claimed in claim 6 is characterized in that: the curve form of described contact-making surface be boss shape, taper shape, circular arc, semicircle, polygon, V-arrangement, in a zigzag, trapezoidal, zigzag and parabola shaped in the combination of one or more shapes.

8, as claim 6 or 7 described a kind of devices that improve coil magnetic fields to moving iron core dynamic response ability, it is characterized in that: the contact-making surface of a described moving iron core and a side end cap is the plane, with the contact-making surface of opposite side end cap be the on-plane surface curved surface.

9, as claim 6 or 7 described a kind of devices that improve coil magnetic field to moving iron core dynamic response ability, it is characterized in that: the contact-making surface of described moving iron core and both sides end cap is identical shaped on-plane surface curved surface.

10, as claim 6 or 7 described a kind of devices that improve coil magnetic field to moving iron core dynamic response ability, it is characterized in that: the contact-making surface of described moving iron core and both sides end cap is the on-plane surface curved surface, and the curvature of a side contacts face shape greater than with the curvature of opposite side contact-making surface shape.

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