JP2002162971A - Method of optimizing spiral horn and optimized spiral horn - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize the basic frequency characteristics of a horn component 2 having a diaphragm 3 and a movable contact 8 of a spiral horn and the resonance frequency characteristics of curling 4. SOLUTION: The horn component is formulated as a motion equation with solenoid electromagnetic force as eternal force and the response speed of a diaphragm system obtained therefrom is analyzed as a boundary condition for a sound field analysis, by which the frequency characteristics of the horn component are calculated. The optimized spiral horn is simulated by matching the frequency characteristics and the resonance frequency of the curling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of optimizing a spiral horn mounted on a vehicle such as a passenger car and a technical field of an optimized spiral horn.

[0002]

2. Description of the Related Art Today, a horn mounted on a vehicle includes:
There is a spiral horn in which a horn component having a diaphragm serving as a sound source (sound generating unit) and curling serving as a spiral unit are combined. In such a spiral horn, the sound resonates in the curling, so that the tone is mellow and comfortable. In such a spiral horn, it is necessary to optimize the frequency characteristics of the sound emitted from the horn component and the resonance frequency in curling.

[0003]

However, conventionally, it has been virtually impossible to determine the relationship between the frequency characteristics of the sound produced from the horn component and the resonance frequency of the curling, and the combination of the horn component and the curling is determined. Is a trial-and-error process that repeats prototypes and experiments, and in the end it is necessary to rely on empirical insights as to whether this area is not optimal. There is a problem that the size is inevitably wasteful and large, and there is a problem to be solved by the present invention.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve these problems in view of the above situation, and the first invention is attracted by the excitation of a solenoid. In optimizing a spiral horn configured by combining a horn component with a diaphragm and curling, the horn component is formalized as a motion equation using a solenoid electromagnetic force as an external force, and a diaphragm system obtained from the motion equation is formulated. The frequency response of the horn component is calculated by solving the response speed as the boundary condition of the sound field analysis, and the calculated frequency characteristic is optimized by matching the resonance frequency of the curling system. This is an optimization method for a spiral horn. The second invention is a spiral horn configured by combining a horn component having a diaphragm attracted by excitation of a solenoid and a curling, and is formulated as a motion equation in which a solenoid electromagnetic force is applied to the horn component as an external force. The frequency response of the horn component is calculated by solving the response speed of the diaphragm system obtained from the equation of motion as the boundary condition of the sound field analysis, and the calculated frequency characteristics are matched with the resonance frequency of the curling system. An optimized spiral horn characterized in that: According to the present invention, the horn component and the curling can be easily optimized by doing in this way, so that the development period can be shortened and the horn can be downsized.

[0005]

Next, embodiments of the present invention will be described. In FIG. 1, reference numeral 1 denotes a spiral horn. The spiral horn 1 is configured using a horn component 2 serving as a sound source and a curling 3 serving as a resonance unit. The horn component 2 includes a diaphragm 4, The casing 5, a fixed iron core (excitation iron core, pole) 6 fixed to the casing 4, an excitation coil (solenoid) 7 for exciting the fixed iron core 6, a movable iron core (shaft) 8 fixed to the diaphragm 4, The fixed contact 9 to be fixed and the fixed contact 9 which move integrally with the movable core 8
As in the related art, each member is configured using various members such as the movable contact 10 that comes into contact with and separates from (ON-OFF to) the same.
When the horn component 2 is powered on, the excitation coil 7 is excited by the contacts 9 and 10 being in the ON state, and accordingly, the movable core 8 receives the electromagnetic attraction of the fixed core 6. The diaphragm 4 is elastically deformed together with the movable core 8 toward the fixed core 6. Then, the movable contact 10 moves, the contacts 9 and 10 are turned off, the excitation of the exciting coil 7 is released, the diaphragm 4 returns to the original posture by the elastic restoring force, and the contacts 9 and 10 are turned on again. Are repeated, and the vibration is generated by the vibration of the diaphragm 4 based on the repetition. In the spiral horn 1, the blown sound is resonated by the curling 3, and the sound pressure is amplified. The spiral horn 1 is different from the flat horn without the curling 3 in that the cores 6 and 8 do not come into contact with each other.

The sound pressure of such a spiral horn 1 (SP
L: Sound Pressure Level, vibration of the movable core 8 at the time of sounding, and the response of the shaft when the movable core 8 was vibrated in white are shown in FIG. 2 by actually measuring a commercially available spiral horn 1.
(A) to (C). First, from the horn sound pressure (SPL) shown in FIG. 2A, it is confirmed that the peak sound pressure of the spiral horn 1 is generated by an integral multiple order component of the primary frequency. This primary frequency is generated at the timing of turning on and off the contacts 9 and 10 serving as the magnetic circuit, and it is confirmed that this is the fundamental frequency (400 Hz (Hertz)) that determines the tone of the spiral horn 1. Is done. On the other hand, regarding the vibration of the movable core 8, when the vibration at the time of sounding (Velocity) and the response (Acceleration) at the time of white excitation are shown in FIGS. It is recognized that the vibration of the movable core 8 at the time of blowing is different from the structural resonance of the movable core 8 itself and is due to the response of an external force. In such a case, the external force is such that the movable core 8 is
The electromagnetic attraction force of the exciting coil 7 acting to approach the above, that is, the solenoid electromagnetic force. From this result, an integral multiple order component of the fundamental frequency of the horn sound pressure of the spiral horn 1 and the vibration frequency of the horn component 2 It is confirmed that the characteristics are the same.

This means that the horn component 2 is made by integrating the diaphragm 4 and the movable core 8 as shown in FIG. 3 (A), and this can be formulated by a one-mass system of motion equation. Infer. Therefore, as shown in FIG. 3B, a spring (equivalent spring coefficient: k) and a dash pot (equivalent coefficient by material: c) are connected in parallel to the diaphragm 4 and the movable iron core 8 (hereinafter referred to as "diaphragm system"). When shown in the combined Kelvin model (Valkt model), the external force f (t) due to the electromagnetic force is

(Equation 1) Is the equation of motion of equation (1). Here, m is the mass of the diaphragm system, that is, the mass of the diaphragm 4 and the movable core 8, and k is the equivalent spring coefficient, which can be obtained by the finite element method. In other words, the load of the diaphragm system is fs
t, the displacement amount when the diaphragm system is electromagnetically attracted is represented by U
When st, k is obtained as k = fst / Ust. The external force f (t) in this case is the above-mentioned solenoid electromagnetic force. If the current and the electromagnetic force are in a linear relationship, and the voltage (V), the resistance (R), and the inductance (L) are used as parameters, FIG. As shown in (C), time (Time) and current (Current)
(D), the gap distance (Gap Distance) and the electromagnetic force (Electr) as shown in FIG.
omagnetic Force), and from this,

(Equation 2) Becomes From the equation (2), the details of the electromagnetic attraction by the current of the magnetic circuit, that is, the external force f (t) are obtained. Here, the coefficient α is the electromagnetic force per unit current at the stationary position of the movable iron core 8, which was obtained by static magnetic field analysis. By doing so, each coefficient of the equation of motion of the horn component 2 is obtained, and the response speed of the diaphragm system is obtained by integrating the coefficients. For the time integration, a central difference method in which the velocity and acceleration were determined as in the following equation was used.

(Equation 3) By substituting these equations (3) and (4) into equation (1), the following equation (5) is obtained.

(Equation 4) This equation (5) shows the switching relationship of the magnetic circuit, and the displacement of the present time and the past time (right formula) is equal to the displacement of the future time (left formula). Means In this equation (5), the initial state in which the power is not turned on is set to time 0 and displacement 0, and an arbitrary time Δt increment is given, so that a future state can be calculated from the past, and the calculated future state can be calculated. Is further substituted into the past part of the equation (5), a further future state (displacement of the movable core 8) is obtained, and by repeating this, the response of the diaphragm at each time interval Δt can be obtained. (FIG. 3E). Furthermore, an ON-OFF algorithm using a switch of the magnetic circuit is also introduced. Here, the point gap (U) of the movable iron core 8 when the current changes from ON to OFF (I = 0)
pg: the gap between the fixed core 6), as shown in FIG. 4, the gap U between the movable core 8 and the fixed core 6 when the current is turned off is controlled by the following condition. Is done. I = 0 at U ≦ Up
g

FIG. 5 shows the result of a solution of the electromagnetic force (Electromagnetic Force) and the response displacement (Displacement) of the movable core 8 given under these conditions, and FIG. 6 shows the result of the Fourier transform of the response result. In this case, the upper diagram in FIG. 5 shows the electromagnetic force, which rises exponentially as can be seen from the equation (2), and the displacement of the movable core 8 attracted to the position is specified. In other words, the above-mentioned current changes from ON to OFF
It is shown that the electromagnetic force becomes 0 when the position of the electromagnetic circuit becomes zero, and the electromagnetic force when the switch of the electromagnetic circuit is turned on and off is reproduced as a sawtooth waveform. The lower diagram of FIG. 5 shows the displacement trajectory of the movable core 8 which is pulled by the electromagnetic attraction. Further, the upper diagram of FIG. 6 shows the result of Fourier transform of the electromagnetic attraction force. From this, the solenoid electromagnetic force (Electromagneti) is shown.
It can be seen that the waveform formed by the switching of c Force) has a fundamental frequency and a component that is an integral multiple of the fundamental frequency. In addition, the lower diagram of FIG. 6 is not a displacement but a response speed (Response) of the movable core 8 because of sound field analysis.
The result of Fourier transform for (Velocity) is shown, and it is also confirmed that this also has frequency characteristics. When sound field analysis is performed using the response speed as a boundary condition, the sound pressure of the spiral horn is obtained. FIG.
Shows the analysis flow. Here, the sound field analysis used sound field analysis software based on the boundary element method.

Next, in order to actually confirm the resonance frequency of the curling 3, the sound pressure of the curling 3 when the diaphragm 4 is forcibly vibrated at the unit vibration is shown in FIG. Here, the vertical axis represents a sound transfer function (Acoustic Transfer Function) as a numerical value obtained by dividing sound pressure by vibration (that is, sound pressure per unit vibration).
n: ATS). As is apparent from FIG. 8, it is confirmed that the resonance frequency of the curling is not an integral multiple of the fundamental frequency (400 Hz) as in the horn component described above.

Then, a simulation for matching the two is performed. However, if the overall sound pressure at that time shows the maximum value, it can be inferred that the optimum condition is obtained. Therefore, assuming that the horn component 2 has a fundamental frequency of 450, 475, and 500 Hz, the response speed when solving the equation of motion is calculated in the same manner, and the calculation result is used as the acoustic transmission of the curling 3 described above. 450, 500Hz
It was confirmed that the frequency characteristic of the response speed of the horn component 2 of 475 Hz did not match the resonance frequency of the curling 3, whereas the resonance characteristic of the horn component 2 of 475 Hz matched at the second and third resonance frequencies (FIG. 450 to 475H for 9
A corresponding graph is shown for a horn component of z). And 475Hz matching like this
FIG. 1 shows the results of evaluation of the horn component having no matching at 430 and 500 Hz using the overall sound pressure (Overall).
0 is shown. Here, the sound source of the horn is a fundamental frequency of the magnetic circuit and an integral multiple of the fundamental frequency, so that the overall sound pressure can be evaluated using the acoustic transfer function and the response vibration (response speed) of the sound source. Incidentally, the overall sound pressure is defined as a sum of a product of a sound source vibration and an acoustic transfer function, which is an integral multiple of a fundamental frequency. That is, overall sound pressure = Σ (“vibration of sound source” × “acoustic transfer function”). And when evaluated in this way, 475 Hz
It was confirmed that the horn component had the highest overall sound pressure.

From the above, a horn component having each of the above-described frequencies as the basic frequency was actually created (adjustment of the basic frequency), and it was examined whether or not the horn component coincided with the result of the above-described simulation analysis. The results are also shown in FIG. As described above, in the case of the actually produced horn component, it was confirmed that the one with 475 Hz had the highest overall sound pressure, and it was confirmed that the result was consistent with the result of the simulation analysis. This means that the above-described simulation analysis method is effective.

As described above, when the present invention is implemented, when one curling is set, the fundamental frequency of the horn component optimal for the curling can be set. Conversely, when a horn component is set, the optimum curling resonance frequency for the horn component can be set, that is, for example, a sound of “A (la)” (sound of a time signal). When it is desired to set a horn component of 440 Hz, a horn component having this fundamental frequency is modeled as a motion equation, its response speed is calculated as a boundary condition for sound field analysis, and matching is performed with the frequency characteristics of the calculated response speed. By creating a curling with a resonance frequency, it is possible to set a spiral horn that is optimized for both, and in such a simulation analysis, it is possible to shorten the design time and improve the resonance characteristics of the curling Therefore, there is no need to increase the size of the spiral horn. So that can also be achieved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a spiral horn.

2A is a graph showing the sound pressure of the spiral horn 1, FIG. 2B is a graph showing the vibration of the movable core during blowing, and FIG. 2C is a graph showing the response of the shaft when the movable core is vibrated in white. is there.

FIG. 3A is a perspective view, a side view, and the like of a diaphragm;
(B) is an explanatory view showing a Kelvin model of a diaphragm system,
(C) is an explanatory diagram of the electromagnetic circuit, (D) is a graph showing the relationship between the gap and the electromagnetic force, and (E) is a graph showing the response state of the diaphragm system at each time interval Δt.

FIG. 4 is an explanatory diagram showing a gap state between a movable iron core and a fixed iron core when current is turned on and off.

FIG. 5 shows the results of the solution of the electromagnetic force and the response displacement of the movable core. The upper figure shows the change state of the electromagnetic attraction force, and the lower figure shows the displacement trajectory of the movable core drawn by the electromagnetic attraction force. FIG.

FIG. 6 is a graph showing an electromagnetic attraction force obtained by performing a Fourier transform, and a lower diagram is a graph obtained by performing a Fourier transform on a response speed of a movable iron core.

FIG. 7 is a flowchart showing an analysis procedure of a simulation of a spiral horn.

FIG. 8 is a graph showing a relationship between a resonance frequency characteristic of curling and an acoustic transfer function of a diaphragm system.

FIG. 9 is a graph showing a relationship between horn components having fundamental frequencies of 450 and 475 Hz and curling resonance frequencies.

FIG. 10 is a graph showing simulation values and experimental values for overall sound pressure of spiral horns having fundamental frequencies of 430, 475, and 500 Hz.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spiral horn 2 Horn component 3 Diaphragm

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Shoichi Matsumoto, Inventor 1-268, Hirosawa-cho, Kiryu-shi, Gunma 1st place Mitsuba Co., Ltd. Ichibanchi Mitsuba Co., Ltd. (72) Inventor Kazuo Igarashi 1-268 Hirosawacho, Kiryu-shi, Gunma

Claims (2)

[Claims] In order to optimize a spiral horn configured by combining a horn component having a diaphragm attracted by excitation of a solenoid and a curling, a kinetic equation using a solenoid electromagnetic force as an external force is applied to the horn component. By formulating, solving the response speed of the diaphragm system obtained from the equation of motion as a boundary condition of the sound field analysis, calculating the frequency characteristics of the horn component, and matching the calculated frequency characteristics with the resonance frequency of the curling system. A method for optimizing a spiral horn, characterized in that it is configured to optimize. 2. A spiral horn configured by combining a horn component having a diaphragm attracted by excitation of a solenoid and a curling, wherein the horn component is formulated as a motion equation using an electromagnetic force of a solenoid as an external force, The frequency response of the horn component is calculated by solving the response speed of the diaphragm system obtained from the equation of motion as a boundary condition for sound field analysis, and the calculated frequency characteristics are matched with the resonance frequency of the curling system. Optimized spiral horn characterized by: