JPH075198U - Actuator for active noise reduction system - Google Patents

Abstract

(57) [Abstract] [Objective] The present invention aims to improve the environmental resistance of the actuator of the active noise reduction system that forms the canceling sound of the opposite phase and equal sound pressure with the noise. [Configuration] A speaker 2 that outputs a noise that is an exhaust sound from the tail pipe 1 and a canceling sound of an opposite phase and equal sound pressure,
In an actuator of an active noise reduction system in which a speaker 2 is installed and has a housing 3 for guiding a canceling sound, the canceling sound guiding portion has a slope such that its exit position is low, and the speaker 2 is positioned farther from the guiding portion. Is also set to a high position.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an active noise reduction system that forms a canceling sound of noise and an antiphase and equal sound pressure, and in particular, the present invention relates to improving the environmental resistance of an actuator that constitutes this system.

[0002]

[Prior art]

 Conventionally, there is an active noise control system described below as a technique in such a field. This active noise reduction system is intended to reduce engine exhaust noise, which is noise that is installed in a vehicle.Generally speaking, there is a speaker that outputs a canceling sound that is in anti-phase / equal pressure with the engine exhaust sound, and a noise The microphone is provided with a microphone for detecting a residual sound that has been canceled and feeding back the residual sound as an error signal, and a controller for forming a cancellation signal using the error signal as a control signal. The microphone and speaker form the actuator of the active noise control system.

FIG. 9 is a diagram showing a structure of an actuator of a conventional active noise reduction system. In the actuator of the active noise reduction system shown in this figure, a speaker 2 is provided near a tail pipe 1 that exhausts exhaust gas from a vehicle engine to the atmosphere. The speaker 2 is provided in the housing 3, and the housing 3 surrounds the rear portion of the speaker 2 and cancels the exhaust sound from the tail pipe 1 by sending the cancel sound from the speaker 2 to the vicinity of the outlet of the tail pipe 1. invite.

[0004]

[Problems to be solved by the device]

 By the way, improving the environmental resistance of the actuator of the active noise reduction system and improving the mounting conditions for this are important issues to prolong the life of the active noise control system. This is because if the speaker 2 is located lower than the cancel outlet of the housing 3, the water contained in the exhaust gas, the water washed by the vehicle, the rain, etc. will enter the housing 3 and the speaker 2 will soak into this water. This is because there is a problem that the speaker is deteriorated if it is not removed properly.

Therefore, in view of the above problems, it is an object of the present invention to provide an actuator for an active noise reduction system that can remove water and improve environmental resistance.

[0006]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a speaker that outputs a canceling sound having an opposite phase and equal sound pressure with noise that is exhaust sound from a tail pipe, and a housing in which the speaker is installed and guides the canceling sound. In the actuator of the active noise reduction system, the guide part for the canceling sound is provided with a gradient so that its exit position is lowered. Also, the speaker is at a higher position than the guide portion there.

When the speaker is at substantially the same height as the guide portion, the inclination between the cone of the speaker and the horizontal surface is larger than the inclination between the guide portion and the horizontal. Furthermore, when there is a recess in the guide portion in front of the speaker, a heat resistant sponge is attached along the bottom of the recess and the guide portion. When the guide portion has a recess in front of the speaker, a metal plate is partially bonded along the bottom of the recess and the guide portion. Further, when there is a recess in the guide portion in front of the speaker, holes are provided in the recess and the bottom of the guide portion, and a lid is bonded to these holes. A heat resistant net is installed in the middle of the guide portion. A step is provided in the middle of the guide portion. A heat resistant net is provided along with a step in the middle of the guide portion. A microphone for detecting the residual sound generated by canceling the noise and using it as an error signal to form a canceling sound is provided horizontally displaced from the vertical direction of the tail pipe that emits the noise.

[0008]

[Action]

 As described above, according to the actuator of the active noise reduction system of the present invention, since the guide portion for the cancel sound has a slope so that the exit position thereof is low, it is difficult for water to be stored in the housing due to the slope of the guide portion. The water adhering to the canceling sound guide part descends due to engine vibration and at the same time evaporates due to the heat of the tail pipe. The loudspeaker being positioned higher than the guide portion there eliminates direct immersion in water. Even if water temporarily splashes on the surface of the speaker, it is immediately discharged to the outlet or evaporated by heat and is less affected by water, which extends the life of the speaker. When the speaker is at substantially the same height as the guide portion, the inclination between the cone of the speaker and the horizontal is larger than the inclination between the guide portion and the horizontal. Therefore, it is easy to remove water from the surface of the cone even if the speaker is not positioned high. Further, when there is a recess in the guide part in front of the speaker, a heat-resistant sponge is attached along the bottom of the recess and the guide part so that the heat-resistant sponge is a spongy porous material. Due to the capillarity, it has the effect of guiding water toward the exit of the cancellation sound guide. The water guided in this way disappears as it is evaporated or dried by the heat of the tail pipe on the way to the outlet. Also, when there is a recess in the guide part in front of the speaker, by partially adhering the metal plate along the recess and the bottom of the guide part, an extremely narrow gap between the bottom and the metal plate is obtained. The same action and effect as described above can be obtained due to the capillary phenomenon of the portion. Further, when there is a concave portion in the guide portion in front of the speaker, a plurality of holes are provided in the concave portion and the bottom of the guide portion, and a lid is adhered to these holes to form a gap, and a capillary is formed from this gap. Based on the phenomenon, water is allowed to seep outside. By installing a heat resistant net in the middle of the guide part, the water that directly enters from the outlet of the canceling sound guide part is stopped by this net and evaporated by the heat of the tail pipe to be removed until it reaches the speaker. . By providing a step in the middle of the guide part, direct intrusion of water is prevented. Furthermore, when this step is used in combination with a heat resistant net, water hits the step and the effect is enhanced. Furthermore, by installing the microphone horizontally from the vertical direction of the tail pipe, it is possible to prevent water contained in the exhaust gas from the tail pipe from rising or falling and hitting the microphone when the vehicle is stopped. The effect of water content disappears. Therefore, such a waterproof effect can prevent deterioration of the microphone due to vapor and prolong its life.

[0009]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. 1 is a diagram showing the structure of an actuator of an active noise reduction system according to a first embodiment of the present invention. The actuator of the active noise reduction system shown in this figure relates to the mounting height of the speaker 2. As shown in the figure, the tail pipe 1 has a slope so that its outlet position is lowered so that the moisture of the exhaust gas flows out to the outside. On the other hand, the cancel sound guide outlet position of the housing 3 also has a slope so that the outlet becomes lower so that water coming from the outside flows to the outside. The speaker 2 shown in this figure (a) is an example that is oriented in the lateral direction with respect to the traveling direction of the vehicle, and its lower end is higher than the cancel sound guide position of the housing 3, and the drainage clearance d1. It is installed in a position that secures (> 0). The speaker 2 shown in this figure (b) is an example in which the speaker 2 is directed downward with respect to the traveling direction of the vehicle, and is higher than the guide position of the cancel sound of the front part, which is the opening, and the housing 3, It is installed at a position that secures the drainage clear lance d2 (> 0). Therefore, it is difficult for water to be stored in the position of the speaker 2 due to the inclination of the housing 3, and the moisture adhering to the interior of the cancel sound drops due to the vibration of the engine and at the same time evaporates due to the heat of the tail pipe 1. Furthermore, the clearance prevents direct immersion in water. It can be seen that even if water temporarily hits the surface of the speaker 2, it is immediately discharged to the outlet, or is evaporated by heat on the way to the outlet so that it is less susceptible to water. Next, a case where the clearance of the speaker 2 cannot be sufficiently secured due to its structure will be described.

FIG. 2 is a diagram showing a structure of an actuator of an active noise reduction system according to a second embodiment of the present invention. As shown in this figure, the position of the speaker 2 is different from that of FIG. 1 in the configuration of FIG. The inclination of the cancel sound guide portion of the housing 3 with respect to the horizontal is θ1 (> 0), and the speaker 2 is placed at the same height as the cancel sound guide portion of the housing 3 and the inclination of the cone that outputs the cancel sound is horizontal. Is set as θ2 (> 0) to set θ2> θ1 so that the inclination of the cone is made larger than the inclination of the cancel sound guiding portion to facilitate the removal of water from the surface of the cone.

FIG. 3 is a diagram showing a structure of an actuator of an active noise reduction system according to a third embodiment of the present invention. When it is desired to increase the diameter of the speaker 2, when there are restrictions on vehicle mounting and acoustic characteristics, it is necessary to form a recess in the housing 3 in front of the speaker 2 as shown in the figure. In such a case, water is likely to collect in this recess, so that the speaker 2 is likely to be immersed in this pool. Therefore, a heat-resistant sponge is attached from this recess to the bottom of the cancel sound guide. This heat-resistant sponge is a sponge-like porous material and has the effect of guiding water toward the exit of the canceling sound guide section due to its capillarity. The water introduced in this way disappears as it is evaporated or dried by the heat of the tail pipe 1.

FIG. 4 is a diagram showing a modification of the structure of the actuator of the active noise reduction system of FIG. Instead of the heat-resistant sponge shown in FIG. 3, a metal plate as shown in FIG. This metal plate is bonded to the recess of the housing 3 and the bottom of the canceling sound guide by spot welding or screwing as shown in FIG. Due to the capillarity in the extremely narrow gap between the bottom and the metal plate, there is the effect of guiding water toward the exit of the canceling sound guide as in the above case. The water introduced in this way disappears by being evaporated or dried by the heat of the tail pipe 1 on the way to the outlet.

FIG. 5 is a diagram showing another modification of the structure of the actuator of the active noise reduction system of FIG. Instead of the heat-resistant sponge shown in Fig. 3, make multiple drain holes for water. As shown in Fig. (A), this drain hole is a hole provided in the recess of the housing 3 and the bottom of the cancel sound guide part. The hole is covered with a lid and the lid is screwed to the bottom. Is. Water flows through a very narrow gap between the lid and the bottom so that it exits on the way. This gap is formed to prevent the cancellation sound from leaking. The holes may be threaded and nuts tightened on the opposite side as shown in Figure (b). This allows water to flow out of the hole through the narrow area between the collar and the bottom of the screw.

FIG. 6 is a diagram showing a structure of an actuator of an active noise reduction system according to a fourth embodiment of the present invention. As shown in the figure, a heat resistant net or sponge is provided in the middle of the cancel sound guide portion. This heat-resistant net removes the water directly entering from the exit of the cancel sound guide section to the speaker 2. Since a material with low acoustic impedance is used for this material, it is possible to achieve both noise reduction effect and waterproof effect.

FIG. 7 is a diagram showing a structure of an actuator of an active noise reduction system according to a fifth embodiment of the present invention. As shown in this figure (b) with respect to this figure (a), steps A and B are provided on the way from the exit of the canceling sound guide part of the housing 3 to the speaker 2 to prevent direct water intrusion. . Further, a step C as shown in FIG. 7C may prevent the intrusion of water directly. Further, it may be used together with the heat resistant net shown in FIG. This further enhances the effect.

FIG. 8 is a diagram showing a structure of an actuator of an active noise reduction system according to a sixth embodiment of the present invention. The microphone 4 is attached to the rear portion of the vehicle near the tail pipe 1, and is provided at a position (above or below) horizontally separated from the vertical upper or lower portion of the tail pipe 1 by a distance d3. This prevents the moisture contained in the exhaust gas from the tail pipe 1 from rising or falling and hitting the microphone 4 when the vehicle is stopped, so that the influence of the moisture disappears. Therefore, due to such a waterproof effect, deterioration of the microphone 4 due to vapor can be prevented and its life is extended.

[0017]

[Effect of device]

 As described above, according to the present invention, the speaker in the housing is less likely to receive water and is less likely to store water, so that the speaker is not affected by water and has a long life. Even when the vehicle is stopped, the water contained in the exhaust gas from the tail pipe does not hit the microphone, so its life is extended.

[Brief description of drawings]

FIG. 1 is a view showing a structure of an actuator of an active noise reduction system according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a structure of an actuator of an active noise reduction system according to a second embodiment of the present invention.

FIG. 3 is a view showing a structure of an actuator of an active noise reduction system according to a third embodiment of the present invention.

FIG. 4 is a diagram showing a modification of the actuator of the active noise reduction system of FIG.

FIG. 5 is a diagram showing another modification of the actuator of the active noise reduction system of FIG.

FIG. 6 is a diagram showing a structure of an actuator of an active noise reduction system according to a fourth embodiment of the present invention.

FIG. 7 is a diagram showing a structure of an actuator of an active noise reduction system according to a fifth embodiment of the present invention.

FIG. 8 is a view showing a structure of an actuator of an active noise reduction system according to a sixth embodiment of the present invention.

FIG. 9 is a schematic view showing the structure of the actuator of the active noise reduction system according to the sixth embodiment of the present invention.

[Explanation of symbols]

 1 ... Tail pipe 2 ... Speaker 3 ... Housing 4 ... Microphone

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masaaki Nagami Inventor Masaaki Nagami 1-228 Goshodori, Hyogo-ku, Kobe, Hyogo Prefecture Inside Fujitsu Ten Limited

Claims (10)

[Scope of utility model registration request] 1. A speaker (2) for outputting a canceling sound having an opposite phase and equal sound pressure to noise that is exhaust sound from a tail pipe (1), and the speaker (2) is installed and guides the canceling sound. An actuator for an active noise reduction system having a housing (3), characterized in that a gradient is provided at a canceling sound guiding portion so that an exit position thereof is lowered. 2. Actuator for an active noise reduction system according to claim 1, characterized in that the loudspeaker (2) is located higher than the guide part there. 3. When the speaker (2) is at substantially the same height as the guide portion, the inclination between the vibrating part of the speaker (2) and the horizontal is made larger than the inclination between the guide portion and the horizontal. The actuator of the active noise reduction system according to claim 1, wherein: 4. The heat-resistant sponge according to claim 2, wherein when the guide portion has a recess in front of the speaker (2), a heat-resistant sponge is attached along the bottom of the recess and the guide portion. Actuator for active noise reduction system. 5. The metal plate is partially adhered along the bottom of the recess and the guide when the guide has a recess in front of the speaker (2). Actuator for the described active noise reduction system. 6. If the guide part has recesses in front of the speaker (2), holes are provided at the bottoms of the recesses and the guide part, and a lid is bonded to these holes. The actuator of the active noise reduction system according to 1. 7. The actuator of the active noise reduction system according to claim 1, wherein a heat resistant net is installed in the middle of the guide portion. 8. The actuator of the active noise reduction system according to claim 1, wherein a step is provided in the middle of the guide portion. 9. The actuator of the active noise reduction system according to claim 7, wherein a heat resistant net is provided along with a step in the middle of the guide portion. 10. A microphone (4) for detecting a residual sound in which noise is canceled and using this as an error signal to perform a feedback to form a canceled sound from a vertical direction of a tail pipe (1) for discharging exhaust gas. The actuator of the active noise reduction system according to claim 1, wherein the actuator is provided so as to be shifted in the horizontal direction.