JP2582032B2 - Equivalent non-polar bidirectional linear solenoid with permanent magnet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bidirectional linear solenoid having a permanent magnet which operates equivalently to non-polarity.

[0002]

2. Description of the Related Art Conventionally, a bidirectional linear solenoid changes the direction of energization to a coil, moves a plunger to the left and right, and when the energization is cut off, the plunger has no holding force and is free. Japanese Patent Application Laid-Open No. 4-287902 (Japanese Patent Application No. 2-327) discloses a non-polar bidirectional linear solenoid.
No. 635).

[0003]

However, this is characterized in that it is non-polar without using a permanent magnet, so that even if a permanent magnet is used, the bidirectional linear solenoid is equivalently non-polar. Has not yet been realized.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to provide a bidirectional linear solenoid using a permanent magnet, which is equivalently non-polar, and has a characteristic feature. A cylindrical magnet 11 magnetized in the N and S poles in the radial direction is fixed to a substantially central portion of a shaft 12 movable left and right, and a plunger portion 10 is fixed.
And the outer peripheries of the side yokes 13 and 14 made of a soft magnetic material and having the cylindrical poles 15 and 16 protrudingly opposed to the outer perimeter of the plunger portion 10 are fixed by a yoke 20 made of a soft magnetic material. . Thus, the cylindrical pole 15
And a gap 19 having a gap length l between the protruding end faces of
The inner circumference of the cylindrical poles 15 and 16 and the plunger 10
Magnetic gaps 17 and 18 having a gap length δ are formed between the magnetic gaps 17 and 18.

[0005]

When the coil 24 is not energized, the cylindrical pole 1
The suction force acting between the plungers 10 and 5 and the plunger 10 causes the plungers 10 to move into cylindrical poles 15 and 16 respectively.
Acts to suck into.

[0006]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG.
FIG. 2 is a sectional side view of an equivalent non-polar bidirectional linear solenoid having a permanent magnet of the present invention, and FIG. 1 and 2, reference numeral 11 denotes, for example, neodymium (N
d) A cylindrical magnet having a relatively large coercive force, such as an anisotropic sintered magnet containing iron (Fe) and boron (B) as main components. It is. That is, N,
S is the magnetic pole. Reference numeral 12 denotes a shaft made of a non-magnetic material or a magnetic material. Reference numerals 13 and 14 denote side yokes made of a soft magnetic material. The cylindrical poles 15 and 16 are protruded so as to face each other, and a gap 19 having a gap length l is formed between the protruding end faces. The inner circumferences of the cylindrical poles 15 and 16 are opposed to the cylindrical magnet 11 of the plunger section 10 via magnetic gaps 17 and 18, respectively, to form a magnetic gap length δ. 20
Is a yoke made of a soft magnetic material.
The outer periphery of 4 is fixed by caulking or the like. 21,21
Is a bearing case made of a non-magnetic material, and 22 and 22 are linear ball bearings.
3 and 23, so that the shaft 12 can slide while maintaining the magnetic gap length δ. 24 is a coil wound around the cylindrical poles 15 and 16, 25
Is a lead wire of the coil 24. FIG. 3 shows the shaft 1
FIG. 3 is a diagram showing a situation where magnetic lines of force pass through each part when 2 is a non-magnetic material, and reference numerals of each part are the same as those in FIGS. 1 and 2. In FIG. 3, solid arrows indicate patterns through which magnetic lines of force generated by the cylindrical magnet 11 pass, and dotted arrows indicate coils 24.
FIG. 3 shows a pattern of passing magnetic lines generated when a direct current is supplied in the directions shown in FIGS. 1 and 3. In the state of FIG. 3, if the magnetic potential on the outer periphery of the cylindrical magnet 11 is Φ, the magnetic flux density B of the magnetic gaps 17 and 18 due to the cylindrical magnet 11 is
Is as shown in Equation 1.

[0007]

(Equation 1)

The attractive force acting on the cylindrical magnet 11 of the plunger part 10 changes the magnetic flux density in the magnetic gaps 31 and 32 between the tips of the cylindrical poles 15 and 16 and the cylindrical magnet 11 by B ₃₁ and B _{32, respectively.} Assuming that the outer diameter of the plunger 10, that is, the outer diameter of the cylindrical magnet 11 is D (D ≧ δ) and the proportional constant is K ₁ , Φ ₃₁ is defined as the magnetic air gap 31 in the magnetic air gap 31.
As magnetic potential of the cylindrical magnet 11, the number 2 of the force to suck the plunger portion 10 to the cylindrical pole 15 serves as (leftward in FIG. 3), the magnetic gap 32, the [Phi ₃₂ magnetic gap 32 The force of Equation 3 acts to attract the plunger portion 10 into the cylindrical pole 16 (to the right in FIG. 3) as the magnetic potential of the cylindrical magnet 11 at.

[0009]

(Equation 2)

[0010]

(Equation 3)

[0011] Next, in FIGS. 1 and 3, when passing a direct current i in the direction shown in the coil 24, magnetomotive force H _i indicated by the number 4 the winding number of the coil 24 as N occurs.

[0012]

(Equation 4)

[0013] yoke 20, than that the permeability of the side yokes 13 and 14 is air and sufficiently large, the magnetic resistance of the magnetic circuit extending from 15 to a cylindrical pole 16 and R _i, recoil permeability of the cylindrical magnet 11 in mu _r ≒ 1.05 is permeability supra material, since it is almost the same as air, when the independent R _i to the position of the cylindrical magnet 11 is constant regarded. Assuming that the magnetic flux density due to the DC current i in the magnetic air gaps 31 and 32 is b ₃₁ and b ₃₂ respectively, the proportional constant is K
They are both as number 5 as _2.

[0014]

(Equation 5)

In the magnetic air gap 31, B ₃₁ and b ₃₁ are added, and in the magnetic air gap 32, B ₃₂ and b ₃₂ are subtracted. Therefore, the force acting to move the plunger 10 to the left in the drawing is positive. And the total suction force _Ft is as shown in Equation 6.

[0016]

(Equation 6)

When the direction of the DC current i is changed, B ₃₁ and b ₃₁ are subtracted in the magnetic gap 31, and B ₃₂ and b ₃₂ are added in the magnetic gap 32, and the plunger 10 is moved rightward in the figure. force -F _t indicated by the number 7 to try to work.

[0018]

(Equation 7)

That is, the solenoid shown in FIG. 1 operates as a bidirectional linear solenoid. FIG. 4 shows the plunger unit 1
0 is a front view showing another embodiment of the present invention, in which reference numerals are the same as those in FIG. In the drawing, the cylindrical magnet 11 of the plunger portion 10 is configured to be equally divided into four in the circumferential direction, generally n (n ≧ 2). 5 and 6 are a side sectional view and a front view showing another embodiment of the plunger portion 10. In the figure, reference numeral 12 denotes a shaft, 41 denotes a cylindrical magnet, and 42 denotes a cylinder made of a soft magnetic material. The cylinder is fixed to the outer periphery of the cylindrical magnet 41 by means such as adhesion or the like to form the plunger portion 10. Alternatively, the structure shown in FIGS. 5 and 6 may be such that the cylindrical magnet 41 is equally divided into n (n ≧ 2) in the circumferential direction.

[0020]

According to the present invention, the magnetic potential Φ on the outer periphery of the cylindrical magnet 11 can be magnetized to be substantially constant except for the vicinity of both end faces thereof by appropriately selecting the magnetizing method. Assuming that the length of the cylindrical magnet 11 is L and the distance from the center plane YY of the cylindrical poles 15 and 16 to the right end of the cylindrical magnet 11 is x, x ≒ 1/2
And x> l / 2 except for x ≒ (L-l / 2)
B ₃₁ま で B ₃₂ even if it moves to <(L−1 / 2). Thus the suction force F ₃₂ In the meantime represented by suction force F ₃₁ with the number 3 represented by the number 2 is the balance, plunger unit 1
No suction force works for 0. That is, there is an effect that the plunger unit 10 becomes equivalently in the non-polar state. When the cylindrical magnet 11 is x ≦ l / 2, particularly, x ≒ l / 2, the force for moving the cylindrical magnet 11 to the right in FIGS. 1 and 3 becomes abnormally large, and x ≧ (L−1 / 2) In particular, x ≒ (L−
1/2), the force for moving the cylindrical magnet 11 to the left in FIGS. 1 and 3 becomes abnormally large. FIG.
The horizontal axis x, vertical axis as _{F t,} a diagram illustrating a relationship _{F t} and x, the positive direction of _{F t} is 1 and 3 the plunger portion 10
Is the force that works to move to the left. F _t indicated by the solid line in FIG. 7 represents i.e. suction force generated only by the cylindrical magnet 11 when not energized to the coil 24.
In FIG. 7, the attraction force when + i and -i direct currents are supplied to the coil 24 is also indicated by dotted lines. When the cylindrical magnet 11 has a ring shape as shown in FIG.
As shown in the drawing, a special magnetizing jig is required, but if it is divided into n (n ≧ 2) as shown in FIG. 4, it can be easily magnetized with a normal magnetizer. effective. The magnetic potential Φ on the outer periphery of the cylindrical magnet 11 can be magnetized almost uniformly except for the vicinity of both end surfaces by appropriately selecting a magnetizing method. It may be difficult to completely eliminate the variation in Φ. In such a case, when the outer periphery of the cylindrical magnet 41 is covered with a cylinder 42 of a soft magnetic material having a high magnetic permeability as shown in FIGS.
Has an effect that the surface magnetic potential becomes constant except for the vicinity of both end surfaces thereof.

[Brief description of the drawings]

FIG. 1 is a side sectional view of an equivalent non-polar bidirectional linear solenoid having a permanent magnet of the present invention.

FIG. 2 is a sectional view taken in the direction of arrows in FIG. 1A-A.

FIG. 3 is a diagram showing a situation in which magnetic lines of force of respective parts pass when the shaft 12 is made of a non-magnetic material.

FIG. 4 is a front view showing another embodiment of the plunger unit 10.

FIG. 5 is a side sectional view showing another embodiment of the plunger section 10;

FIG. 6 is a front view showing another embodiment of the plunger unit 10.

FIG. 7 is a diagram showing a relationship between _Ft and x.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Plunger part 11 Cylindrical magnet 12 Shaft 13, 14 Side yoke 15, 16 Cylindrical pole 17, 18 Magnetic gap 19 Air gap 20 Yoke 22, 22, Linear ball bearing 24 Coil 31, 32 Magnetic gap 41 Cylindrical magnet 42 Cylindrical

Claims (3)

(57) [Claims] 1. A cylindrical magnet 1 magnetized in N and S poles in a semi-monitoring direction at a substantially central portion of a shaft 12 movable left and right.
1 is fixed to form a plunger portion 10, and a side yoke 13 made of a soft magnetic material and having cylindrical poles 15 and 16 protrudingly opposed to the outer periphery of the plunger portion 10, respectively.
And 14 are fixed by a yoke 20 made of a soft magnetic material. Thus, a gap 19 having a gap length l is formed between the protruding end surfaces of the cylindrical poles 15 and 16, and the cylindrical poles 15 and 1 are formed.
6 and the outer circumference of the plunger portion 10
Characterized in that the magnetic gaps 17 and 18 are configured,
Equivalent non-polar bidirectional linear solenoid with permanent magnet. 2. The permanent magnet according to claim 1, wherein the cylindrical magnet 11 of the plunger portion 10 is equally divided into n (n ≧ 2) in the circumferential direction. Has an equivalent non-polar bidirectional linear solenoid. 3. The plunger section 10 is constructed by fixing a cylinder 42 made of a soft magnetic material to an outer periphery of a cylindrical magnet 41. The plunger section 10 has a permanent magnet according to claim 1. , Equivalent non-polar bidirectional linear solenoid.