WO1981002501A1 - Magnetic circuit for an electro-mechanical transducer of a dynamic electricity-type - Google Patents

Abstract

Generally, an electro-mechanical transducer of a dynamic electric type, typified by the operational principle of a loudspeaker, or microphone, or the crossing magnetic field produced when a moving coil (29) or a moving conductor (33) is supplied with signal current disturbs the magnetic field within magnetic gaps (24, 32), causing distortions in the output thereof. A magnetic circuit for an electro-mechanical transducer of a dynamic electric type, is provided for correcting the above-mentioned distortions, in which compensating coils (27, 28) or compensating conductors (34) are provided within the magnetic gaps (24, 32) or grooves (35, 36, 37) formed in the surface of magnetic poles (25, 26, 30, 31). The compensating coils (27, 28) or conductors (34) are supplied with a current corresponding to the signal current so as to produce a crossing magnetic field counter to the crossing field produced by the moving coil (29) or the moving conductor (33) supplied with the signal current, so that disturbances in the magnetic field within the magnetic gaps (24, 32) are prevented.

Description

By flowing current inside! ) 'Cause, .. 10 electromagnetic repulsion or distortion to the electromagnetic electromotive force generated because the'磁Ga鎳distribution disturbance of the original magnetic field caused ^present:. Inventions are made to reduce the disturbance of the ¾ mosquito line distribution, Thus the force Improve the distortion in the picture ^;

 Background technique

, - '. ¾ ^！？ ス ピー カ - ©磁気回路入門 - - 3 ) ^用'新案出願公告. 昭 4 4 - 8 0 4 0

,-'. ¾ ^! ? Speaker-© Introduction to Magnetic Circuits--3) Notice of application for new model for ^.

',' Name of the device Speaker.

 4) Patent application public announcement 5 1 — 8 5 6 9

5 Title of Invention · Magnetic Circuit ^: - ^:

 '' Disclosure of the invention

 As an example of implementing the invention, a method of driving a loudspeaker for a relatively versatile production machine will be described. Each of the following two forms will be described, which are roughly classified into those using a conductor in a shape 10 and those using a ribbon or a leaf-like conductor.

 In Fig. 1, the air gap (3) formed by the central magnetic pole (1) and the outer magnetic pole (2) has a nearly equal magnetic field due to the lines of magnetic force (4) passing between the magnetic poles. ]), The movable core (6) wound around the bobbin (5) in the space (3) is supported so that it can move only in the direction of the 15-axis shaft, that is, the direction of the arrow (7). ¾: The repulsive force generated in the magnetic field line (4) and the dynamic coil (6) due to the signal current flowing in the coil (6) and the driving force (6) Moves back and forth in the direction of the arrow (), and the conversion causes the sound engineer attached to the tip of the bobbin to vibrate, which converts the electrician 20 energies into sound. In this case, the converted sound; ■ The shape of the m force keeps the distortion of the signal current waveform small: 'The driving force acting on the movable coil (6) changes the waveform of the signal current. The size 'must be proportional, and for that purpose the force line in the air gap (3) (4)

 '' It is required that the distribution is uniform, that is, a uniform magnetic field. The shape of the central magnetic pole (1) and the external magnetic pole (2) are of course

O?,: PI VIPO , Magnetic poles (1), (2) a gap (3) to the contact portion of the wood _贊;. The is designed in consideration of the conditions of saturation, etc. Shoshu field line but § customary, actually moving As one of the causes of the distortion of the change waveform of the driving force acting on the coil (6) and finally the distortion of the sound output, 5 distortion of the magnetic field due to the signal current is large. It is considered as.

 When a signal current flows through the movable coil (6), the signal is separated from the existing magnetic field lines (4).

-A new magnetic force に よ る, commonly known as a cross magnetic field (8), is generated by the signal current. Now, assuming that the direction of the instantaneous cross magnetic field (8) is in the direction of the arrow (9), the distribution of the magnetic field lines (4) is distorted as shown in Fig. 2, which distorts the existing magnetic field lines (4). Distortion

10 Occurs. As a prima facie theory, this distorted line of magnetic force (4) tends to return to its original shape, and this force acts on the movable coil (6) as a driving force in the direction of the arrow (10). At a certain point, the traveling direction of the movable coil (6) is coarser than when the density of the lines of magnetic force (4) is the same as the original magnetic field, and the moving direction of the movable coil (6) changes from the signal current to the movable coil (6). When the energy transmitted is-an equal magnetic field

Since it is smaller than the value of 15, the driving force acting on the movable coil (6) is reduced, and the motion mode of the coil (6) is distorted. This is when the average magnetic flux intensity of the magnetic force ( ⁴ ) crossing the movable coil ( ⁶ ) is [B], the total winding length of the movable coil is [], and the magnitude of the signal current is [S]. The repulsive force [F] is:

20 F = k B... And, as shown in Fig. 2, the magnetic force 妾 crossing the movable coil (6) in the direction of travel is Of magnetic lines of force within (4)

If the teaching is equal to the total number of field lines (4) in the case of the equal magnetic field shown in Fig. 1, naturally, the average in the case of low distortion is considered to be very low.

As a result, it is assumed that the driving force of the movable coil (6) will decrease and distortion will occur. Can be explained. Furthermore, as the signal current increases, the distortion of the magnetic field lines (4) increases, so that the amplitude distortion increases, and a change in the signal current may cause a phase lag in the change in the driving force.

 As a conventional technique to reduce the above adverse effects, a method of reducing the influence of the cross-magnetic field by reducing the influence of the cross magnetic field by approaching the magnetic field of the air gap near the magnetic pole surface to saturation, and a conductive short-circuit ring on the magnetic pole surface The secondary current of the signal current flowing through the movable coil is applied to it, and countermeasures such as canceling the J9 cross magnetic field by the magnetic field generated by the current are taken. However, there is a problem with the material in order to bring the magnetic field on the pole surface close to the saturation value, and there is a problem in terms of material, and the tendency to increase the price is not avoided, and the countermeasure by the short-circuit ring shows an effective effect. However, there is a drawback that the effect in the extremely low frequency range is reduced.

 In the present invention, as shown in FIG. 3, a compensating coil (11) is provided in an air gap (3) to positively cancel a cross magnetic field (8) generated by a movable coil (6). A current for canceling the cross magnetic field (8) is passed through the metal (11), and the characteristics can be improved with an extreme increase in the material used. The current flowing through the compensation coil (11) is obtained by amplifying the shape of the signal current supplied to the movable coil (6) by another amplifier or by passing the signal current through a transformer. Although the simplest method is conceivable, the simplest method is to connect a movable coil (6) and a compensation coil (11) in series considering the polarity and treat both ends as input terminals for the speed. It is good. As the fertility to be improved, not only the apparent distortion of the sound output is improved, but also the phase characteristics of the output waveform, particularly the rising characteristics of the ¾ shape in the low frequency range are remarkably improved.

Next, Fig. 4 shows the source of a speaker using a ribbon or leaf-shaped conductor. This is an example showing the principle. The gap (14) formed by the opposing magnetic poles (12) and (13) has a magnetic field line C15). The movable conductor (17) supported at both ends by moving it in the direction of arrow (16) so that it has flexibility as a whole or only at both ends. I do. When a signal current flows through the movable conductor (17), a repulsive force generated between the movable conductor (17) and the magnetic field line (15) generates a driving force in the direction of the arrow [16] on the movable conductor ( ₁₇ ) and moves. The original magnetic field is disturbed as shown in Fig. 5 due to the cross magnetic field (18) generated around (). This results in having the coiled conductor

Similar to the case described in 10) (1) According to the theory, the sound output radiated directly from the sound conductor (17) or read out to the movable conductor (17) causes distortion. As shown in Fig. 6, the signal current is applied to the compensating conductor (19) fixed in parallel with the movable conductor (17) and the movable conductor (17) to cancel the distortion of the magnetic field. Crossed magnetic field (18) generated by flowing

The characteristics can be improved by passing the other current.

 As described above, the explanation example was taken for audio speakers.However, it can be applied to other driving parts such as measurement equipment and control equipment, as well as electromagnetic equipment such as microphones and vibration pickups that have similar structures. Equipment that uses static power, such as power generation coils and power generation ribbons

²⁰ ) Due to the crossing magnetic field generated), the original magnetic field is disturbed and the electric output waveform is distorted. It is evident that the distortion of the output can be improved by passing electricity to cancel the magnetic field.

 As shown in Fig. 3 and Fig. 6, when the compensation coil (6) and the compensation conductor (19) are provided in the gaps (3) and (14), the gaps (3) and

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1 · \ νι? Ο: Since the dimension of (14) increases, the total number of lines of magnetic force decreases, which may lead to a disadvantage in performance such as a decrease in efficiency. In such a case, the one using the movable coil (6) is in contact with the air gap (3) of the center magnetic pole (1) and / or the outer magnetic pole (2) as shown in Fig. 7. Casting (20), (21) is provided along the surface, and a compensation coil (11) is buried in it, and a ribbon-shaped or leaf-shaped movable conductor (17) is used. As shown in Fig. 8, grooves (22) and (23) are formed along the conductor (17) on the surface of the opposing magnetic poles (12) and (13) in contact with the air gap (14). And the compensation conductor (19) is embedded in it. By doing so, it is possible to reduce the increase in the effective dimension of each of the gaps (3) and (14), and to prevent a decrease in efficiency.

 BEST MODE FOR CARRYING OUT THE INVENTION

(1) When coiled conductor is used

 FIG. 9 is a vertical cross-sectional view of a dynamic loud-speech force embodying the present invention D, which is compensated for in the air gap (24) along the surfaces of the center pole (25) and the outer pole (26). This is the same as general loud-speaking force except that coils (27) and [28] are fixed. The compensation coils (27) and (28) have the same winding density as the movable coil (29), that is, the same number of turns as the unit length in the axial direction of the movable coil (29). If the compensation coil 'is divided into two as shown in the figure, the total number will be the total number, and the length will be roughly the same as the length of the movable coil (29) or in the gap (24) The range is the same length as the effective length of the magnetic field. For example, as shown in Fig. 10, the direction of the crossing magnetic field generated by each coil when a common current flows through the movable coil (29) and the compensation coil (27), [28] is read as shown in Fig. 10. It is connected in series so that it is reversed.

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V IPO (2) When using a ribbon-shaped or leaf-shaped conductor

 FIG. 11 is a two-sided view of the soot force implementing the present invention. FIG. 11) shows the magnetic poles (3Q) and (31)] formed in the gap (32) formed parallel to the movable conductor (33). This is the same as the conventional spin force except that the compensating conductor (34) is provided so as to sandwich it. The compensating conductor (34) and the crossing magnetic field generated by the movable conductor are arranged so that the signal current flowing in the movable conductor (33) turns back and flows in the opposite direction. Connected so that it is upside down.

 (3) Implementation method that does not reduce efficiency

 As shown in Fig. 12, the gaps between the magnetic poles (25) and (26) are shown in Fig. 12 in order to prevent a decrease in efficiency due to an increase in the gap size for providing a compensation coil or compensation conductor. Grooves (35) and (36) are provided on the surface in contact with [24] along the winding direction of the movable coil (29), and compensation coils (27) and (28) are embedded in them. By doing so, the increase in the size of the gap (24) can be reduced, and a decrease in efficiency can be prevented.

 Similarly, in the case of using a ribbon or leaf-shaped conductor, as shown in Fig. 13, a groove is formed along the movable conductor (33) on the surface of the magnetic poles (30), (31) in contact with the gap (32). (37) is provided, and the compensating conductor (34) is embedded in it.

 BRIEF DESCRIPTION OF THE DRAWINGS

 Fig. 1] 9 Up to Fig. 8 is for explanation of "Disclosure of invention", Fig. 9! ) Figures up to Fig. 12 are drawings for explaining "the best mode for carrying out the invention".

Fig. 1 is a drawing showing the generation of a crossing magnetic field in a radiating beaker using a coil-shaped conductor. It is a drawing provided with a compensation coil for canceling. Fig. 4 is a drawing showing the generation of a crossover magnetic field by the speed using a ribbon or a leaf-shaped conductor. Fig. 5 is a drawing showing the state where the magnetic field lines are disturbed by the crossing magnetic field. Is a drawing provided with a compensating conductor for canceling the cross magnetic field.

 FIG. 7 is a drawing showing an example in which a compensation coil is embedded, and FIG. 8 is a drawing showing an example in which a compensation conductor is embedded in a groove provided on each magnetic pole surface.

 FIG. 9 and FIG. 10 are drawings showing an example in which the present invention is applied to a Loudsby force using a coil-shaped conductor.

 FIG. 11 is a diagram showing an example in which the present invention is applied to a speaker using a ribbon-shaped or leaf-shaped conductor.

 FIG. 12 is a drawing showing an example in which the compensation coil is stored, and FIG. 13 is an example in which the compensation conductor is stored in grooves provided on the surface of the magnetic pole.

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Claims

Description of reference numerals in drawings  (1) Each of the drawings for "Disclosure of Invention"- 1… Center magnetic pole, 2… Outer circumference ¾pole, 3… Gap, 4… Line of magnetic force, 5… Bobbin, 6… Movable coil, 7… (Indicates the direction of movement of the movable coil) , 9… (indicates the direction of the cross magnetic field), 10… (indicates the direction in which the driving force acts on the movable coil), 11, 11… compensation coil, 12… magnetic pole, 13… magnetic pole,  14 ... air gap, 15 ... magnetic field lines, 16-(indicating the direction in which the movable conductor moves) arrow, 17 ... movable conductor, 18 ... cross magnetic field, 19 ... compensating conductor, 20 (provided in the center magnetic pole) groove, 21 … Groove (provided on the outer magnetic pole), 22—groove (provided on the magnetic pole ((12))), 23.… groove (provided on the magnetic pole ((13))) 0  (2) Each of the drawings for "Best mode for carrying out the invention"  24 ... air gap, 25 ... center magnetic pole, 26 ... outer peripheral magnetic pole, 27 ... compensation coil, 28 ... compensation coil, 29-movable coil, 30 ... magnetic pole,  31 ... magnetic pole, 32 ... air gap, 33 ·--movable conductor, 34 ... compensation conductor, 35 ... groove (provided on the center magnetic pole), 36 ... (provided on the outer magnetic pole), 37 (provided on the magnetic pole) Toto It is. Ten  The scope of the claims  A compensation coil or movable conductor placed between the movable coil and the movable conductor or within the life span provided on the surface of the magnetic pole from the surface in contact with the gap of the magnetic pole. Electromagnetic drive and generator characterized by flowing a current to cancel the cross magnetic field generated by the signal current flowing through ¾ ^ 0 O PI  ,, ATI0