KR100358611B1 - Devices consisting of baffles and loudspeakers, and loudspeakers for use with these devices - Google Patents

Abstract

The invention relates to a device consisting of a baffle 41 and a loudspeaker 1 wherein the stiffness of the chassis of the loudspeaker is adapted to reduce the transmission of vibrations from the loudspeaker to the baffle.

Description

Devices consisting of baffles and loudspeakers, and loudspeakers for use in the devices

Such loudspeakers are disclosed in European Patent Publication No. 0,516,471. Known loudspeakers include a chassis having a magnet system and a diaphragm, by which the loudspeaker can be installed in the device. A coil connected to the diaphragm cooperates with the magnet system to drive the diaphragm. When the diaphragm is driven, a reaction force is applied to the magnet system. This force is transmitted by the chassis to the device in which the loudspeaker is installed. To minimize this transfer of force, the magnet system is connected to the chassis via a rubber suspension. By providing very low stiffness to this rubber suspension, the movement of the magnet system is insulated from the chassis. A disadvantage of known loudspeakers is that isolation is only effective for higher frequencies. Another disadvantage of the known loudspeakers is that vibrations of the diaphragm are transmitted to the device through the suspension of the diaphragm, which can cause unsuitable vibrations in the device, in addition, the rubber suspension can be used for additional parts and during manufacture of the loudspeaker. Requires additional assembly process.

The present invention provides an installation element for installing a loudspeaker on a baffle, and an installation element that is movable in an excursion direction and by a first suspension having a first stiffness K ₁ in the excursion direction. A magnet system having a second mass M ₂ connected to the installation element by a diaphragm having a first mass M ₁ and a second suspension having a second rigidity K ₂ in the deviation direction. It relates to a device consisting of a loudspeaker and a baffle. It is to be understood that the stiffness of the suspension refers to the ratio between the force applied to the suspension point and the deviation of the suspension point as a result of this force.

The present invention also relates to a loudspeaker for use in the apparatus described in the opening paragraph.

1 shows an embodiment of an apparatus according to the invention.

2 is a cross-sectional view of a first embodiment of a loudspeaker according to the invention for use in an apparatus according to the invention.

3 shows a schematic representation of the relative mass and stiffness of a loudspeaker according to the invention in the frequency range of 0 to 600 Hz.

4 shows vibration transmission of baffles from a loudspeaker according to the invention as a function of frequency for a number of different suspensions of the magnet system for the installation element.

5 shows a second embodiment of a loudspeaker according to the invention for use in an apparatus according to the invention.

6 shows a third embodiment of a loudspeaker according to the invention;

It is an object of the present invention to improve the device of the type defined in the opening paragraph to reduce the transmission of vibration of the baffle of the device from the loudspeaker.

To achieve this object, the device according to the invention

It is characterized by that.

Stiffness (K ₁ , K ₂ ) is generally expressed in N / m, and mass (M ₁ , M ₂ ) is expressed in kg. The present invention is based on the recognition that both the diaphragm and the magnet system are vibrated when the loudspeaker is driven and these two parts transmit the vibration to the installation element of the loudspeaker as power. It can be seen that, by the balancing action according to the aspect of Equation 1, the power applied on the mounting element by the magnet system and the power applied on the mounting element by the diaphragm are complementary to each other. When the aspect of Equation 1 above is applied, this complementary relationship will be valid over a large frequency range. It has been found that this aspect can induce loudspeakers that can actually perform very well. Due to this recognition, it has been demonstrated that a substantial reduction in the vibration transmission of baffles from loudspeakers can be achieved even with very large tolerances in the manufacture of loudspeakers.

An embodiment of the device according to the invention

It is characterized by that.

The aspect of Equation 2 above can reduce vibration transmission from the loudspeaker to a device in the middle of the desired frequency range by about 20 dB compared to a device with a loudspeaker without any aspect. For audio and television devices, the desired frequency range is from 0 to 600 Hz, because in this range resonance of the housing of such equipment may occur. This resonance is excited by the loudspeaker, thus causing troublesome noise. In addition, the shadow mask in the water tube of the television device may vibrate as a result of the vibration of the loudspeaker being transmitted to the shadow mask. Such vibration of the shadow mask results in deterioration of the image quality of the television device. By the proposed aspect, the vibration in the device is reduced to an acceptable level without any special steps for damping the vibrations required for the device.

One embodiment of the device according to the invention consists of a chassis in which the loudspeaker has a magnet system and mounting elements, the chassis having a shape that is compliant to the direction of vibration, the rigidity K ₂ of the second suspension being primarily the compliance of the chassis. It is characterized by being determined by (compliance). It has been found that the stiffness required for the suspension of the magnet system can be obtained by providing a chassis of a suitable shape. This shape can be obtained by simple adjustment of the die from which the chassis is manufactured.

One embodiment of the device according to the invention is characterized in that the compliance of the chassis is obtained as a meander shape. By this aspect, the vibration direction of the diaphragm has the required value, and the rigidity of the chassis in the other direction can remain high. The high stiffness in the other direction is suitable for holding the coil, which is fixed to the diaphragm and located in the gap of the magnet system, precisely in the center of the gap.

One embodiment of the device according to the invention is characterized in that the chassis is made of plastic. If it is desired to reinforce with fibers such as carbon fibers or glass fibers, the plastic may be for example polyvinyl chloride or polystyrene. An advantage of this embodiment is that complex shapes such as grain shapes can be molded at low cost by the injection molding die.

An embodiment of a loudspeaker according to the invention is constructed as described above.

The invention is described below in more detail with reference to the drawings as examples below.

The examples are shown diagrammatically and the drawings are arbitrary and do not always have the same accumulation.

1 shows a device according to the invention, showing a television device 40 containing a loudspeaker 1. This loudspeaker 1 is provided on the baffle 41. The television device 40 also includes a water tube 43 provided with a shadow mask 45 therein. In modern television sets, more attention is paid to the sound quality produced by such sets. Moreover, the output delivered by the loudspeaker 1 is constantly increased. Since the loudspeaker 1 vibrates according to the frequency of the generated sound, the vibration is transmitted to the baffle 41 of the device 40, and the vibration is transmitted through the baffle 41, for example, the shadow mask 45, or the like. Is passed to other parts of the device. If the amplitude of the vibration of the shadow mask 45 exceeds a predetermined value, this will obviously prove itself as a degradation of the image quality generated by the water tube 43. In addition, vibration of the baffle 41 causes unacceptable noise.

2 shows in detail a device 40 with a baffle 41 and a loudspeaker 1. The loudspeaker 1 has mounting means 3 for installing the loudspeaker 1 on the baffle 41. The loudspeaker 1 also includes a diaphragm 10 that can move in the declination direction 5 to emit sound. The diaphragm 10 is connected to the installation means 3 by a first suspension, in which case the compliant peripheral part 11 has a first rigidity K ₁ in the deviation direction 5. The loudspeaker 1 also comprises a magnet system 20 having a second mass M ₂ and connected to the mounting means 3 by a second suspension, which is formed by the chassis 21 of the present invention. The chassis 21 has a shape that conforms to the deviation direction 5. Thus, the magnet system 20 is suspended in the installation element 3 through the chassis 21 having the second stiffness K ₂ . The structure of the chassis 21 is a ratio between the second stiffness K ₂ and the mass M ₂ of the magnet system and the ratio between the first stiffness K ₁ of the first suspension and the mass M _{1 of the} diaphragm. Are formed to be substantially equal to each other.

3 schematically shows the forces exerted mutually by the various parts. Excitation of the coil 15 shown in FIG. 2 causes the power F ₀ to be applied to the diaphragm 10 shown as the M ₁ block in FIG. 3, and the same but opposite force (-F ₀ ) is applied to FIG. It is applied to the magnet system 20, shown as M ₂ block. The diaphragm 10 is connected to the mounting element 3 by the suspension 11 having the first rigidity K ₁ . The force F ₀ applied to the diaphragm 10 exerts a force F ₁ on the installation element 3. The magnet system 20 is connected to the mounting element 3 by a suspension 21 having a second rigidity K ₂ . Force (-F ₀₎ applied to the magnet system 20 applies a force (-F ₂₎ for the installation element 3. Furthermore, the diaphragm 10 and the magnet system 20 have a third rigidity K ₃ , exert a force (-F ₃ ) on the cone, and apply a third suspension (F ₃ ) to the magnet system. 13). This third suspension corresponds to the central diaphragm 13 of FIG. 2. This central diaphragm 13 acts to center the coil 27 of the magnet system 20. In order to ensure that this function is performed correctly, this central diaphragm 13 is generally arranged near the magnet system 30. In this case the central diaphragm 13 is connected to the installation element 3 and the diaphragm 10, the stiffness K ₁ must first be calculated from the sum of the stiffness of the periphery 11 and the central diaphragm 13. .

The present invention is based on the recognition that vibration transmission from the loudspeaker to the baffle 41 can be prevented when the sum of the powers F ₁ , -F ₂ applied on the installation element is zero. This requirement can be met by selecting the parameters K ₁ , K ₂ , M ₁ , M ₂ at a predetermined ratio. The way this ratio is selected is as follows. The sum of the power of the mass (M ₁₎ and generates a speed (V _1), which depends on the frequency (f) of the force (F ₀₎ applied through the add non-conductance (Y _M1) of the mass (M _1). This speed V ₁ exerts a force F ₁ on the installation element 3 via the first stiffness admittance Y _K1 . Expressed in terms of, this is:

V1 = (F ₀ -F ₃ -F ₁ ) Y _M1

Likewise,

V ₂ = (F ₀ -F ₃ -F ₂ ) Y _M2

Since this situation describes the case where there is no vibration transmitted to the installation element, it is assumed that the installation element is fixed. The required ratio can be derived by assuming that the forces F ₁ , F ₂ are equal to each other. This results in the following expression.

The admittance of mass (M) is Is given by

Admittance of stiffness (K) Given by

Where ω = 2πf.

With Equation 5

To provide.

When the condition of equation 6 is met, the sum of the forces applied to the mounting element 3 is _zero regardless of the frequency of the applied force F ₀ . This prevents the transmission of vibrations from the loudspeaker 1 to the baffle 41 so that undesirable noise or disturbance of image quality does not occur.

4 shows in logarithmic scale the transfer of the applied force F ₀ to the baffle 41 as a function of the frequency f for a number of systems (transfer is the sum of the forces applied to the installation element 3 (F). ₁ -F ₂ ) and the applied force (F ₀ )}. Curve 50 shows the delivery of a known system to the typical stiffness K ₂ of the second suspension. Curve (53,55) indicates a transmission for a system with optimum rigidity (K ₂₎ ± 20% deviation of the rigid (K ₂₎ from the, best rigidity (K ₂₎ is given by the equation (6). Deviation from the optimum stiffness generates peaks in the transmission curves 53, 55, whereby the transmission of vibrations from the loudspeaker 1 to the baffle 41 is amplified in a particular frequency band. However, for most related frequency ranges, the transmission of vibrations is substantially reduced by the aspect according to the invention. In this case, the suspension 11 of the diaphragm 10 exhibits attenuation, resulting in a finite quality factor of the first resonant system formed by the diaphragm 10 and the suspension 11. In this case, since the second suspension also exhibits attenuation, the second resonant system including the magnet system 20 and the second suspension 21 also has finite property coefficients. It has been found that even if deviating from the optimal value for K ₂ , the two coefficients can still result in a substantial reduction in vibration transmission from the loudspeaker 1 to the baffle 41.

5 shows another embodiment of a loudspeaker for use in the device according to the invention. In this embodiment the compliance of the chassis 21 is obtained by the grain shape 25. This grain shape is obtained by providing a slot 26 with a columnar row in the chassis 21, which slot extends perpendicular to the deviation direction 5 of the diaphragm 10, wherein the row Are biased from each other. This grain shape 25 is particularly suitable because it allows the required stiffness to be obtained in the deviation direction 5, while very large stiffness can be obtained in the direction perpendicular thereto. This is suitable because the coil 15 is arranged in the narrow gap 27 of the magnet system (see FIG. 2). The low stiffness of the chassis 21 in the direction perpendicular to the vibration direction 5 allows the coil 15 to collide with the magnet system 20, thereby damaging the correct operation of the loudspeaker 1.

The chassis 21 is suitably made of plastic. Such plastics can be, for example, polyvinyl chloride or polystyrene reinforced with fibers such as carbon fibers or glass fibers.

In the loudspeaker according to the invention shown in FIG. 6, the chassis 21 comprises a plurality of, in this embodiment, three integral hinge elements 65, which are evenly spaced in the circumferential direction of the loudspeaker ( 6 shows only 1.5 hinge elements). Each of the hinge elements 65 has two rod-shaped hinge bodies 65a and an integral hinge 65b, interconnecting the hinge bodies 65a in a manner as shown in the figure, and at one end the chassis portion 21a. Is connected to the chassis 21b at the other end. In this embodiment, the chassis 21 and the hinge elements 65 are made of plastic and can be configured as a single injection molded article. This configuration achieves low stiffness in the main direction of the loudspeaker, i.e. in the deviation direction 5, and is well suited to hinder translational motion in other directions and rotation around the axis in all directions. This hinge element 65 can generally be used in interconnection with two members having predetermined rigidity.

It should be understood that the present invention is not limited to the examples shown herein. Many other embodiments are possible without departing from the scope of the invention. For example, the diaphragm 10 and the magnet system 20 may be interconnected by a plurality of suspensions or connected to the installation element 3. However, the concept of the present invention makes it possible to simply determine the requirements that must be met in this situation in order to reduce vibration transmission from the loudspeaker of the device 40 to the baffle 41.

Claims (6)

An installation element 3 for installing a loudspeaker on the baffle, The diaphragm 10 having a first mass M ₁ , which is connected to the mounting element in a biasing direction by a first suspension 11 having a first rigidity K ₁ , and is movable in the biasing direction 5. And, A baffle 41 connected to the installation element in the biasing direction by a second suspension 21 having a second rigidity K ₂ , and having a magnet system 20 having a second mass M ₂ ; In the device 40 consisting of a loudspeaker 1, Apparatus consisting of a baffle and a loudspeaker, characterized in that. The method of claim 1, A device consisting of a baffle and a creator, characterized in that. The method according to claim 1 or 2, The loudspeaker 1 comprises a chassis 21 having the magnet system 20 and the installation element 3, The chassis has a shape compliant with the deviation direction 5, Stiffness (K ₂ ) of the second suspension (21) is a device consisting of a baffle and a loudspeaker, characterized in that determined by the compliance of the chassis. The method of claim 3, wherein The baffle and loudspeaker, characterized in that the compliance of the chassis (21) is obtained by a grain shape (25). The method of claim 3, wherein The chassis (21) is made of plastic. Loudspeaker for use in the device according to claim 1.