Helmet sound system

Abstract

To provide an acoustic device for a helmet capable of comfortably running a motorcycle by solving a specific problem generated when the motorcycle is run.SOLUTION: An acoustic device for a helmet is used by being attached to a helmet for a motorcycle, and includes an acoustic device body for generating a drive signal, and a vibration-type acoustic unit that is fixed to right and left side surfaces of the helmet and generates sound by vibrating the helmet by the drive signal. Since sound is generated by a drive signal obtained by synthesizing a sound signal that inverts a phase of external noise detected by an external sound microphone in a vibration-type sound unit with a sound signal of music to allow external noise to be noise-canceled, the motorcycle can travel comfortably.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an acoustic device for a helmet. More specifically, it relates to an acoustic device for a helmet that is attached to and used with a helmet for a motorcycle.

Background Art

[0002] In recent years, there has been a demand for a device that allows sounds to be heard while wearing a helmet for a motorcycle. In this case, it is necessary to solve the specific problems that occur when riding a motorcycle so that the motorcycle can be ridden comfortably.

[0003] As an acoustic device for a helmet having these conventional configurations, there is one disclosed in Non-Patent Document 1. This acoustic device is an incall device that enables a call while riding a motorcycle, and is configured to enable an intercom conversation between up to 8 of the same incall devices. Also, if paired with a mobile terminal such as a smartphone via Bluetooth (registered trademark), while communicating with touring companions and confirming safety, music and GPS guidance can be freely listened to while enjoying the motorcycle ride. This incall device has a Bluetooth module, two speakers connected to the Bluetooth module by a cable, a microphone, an operation button for operating the volume, etc., and an antenna unit.

[0004] Here, this intercom device is specifically designed for motorcycle helmets, etc., as disclosed in Non-Patent Document 2, and this helmet is equipped with a configuration for mounting the intercom device. Specifically, the inside of the helmet has recesses and grooves near the ears, and two speakers are housed and mounted in the recesses, with cables routed and stored in the grooves. The microphone is also configured so that the base of the arm can be mounted in a similar manner. The lower edge of the rear of the helmet bulges slightly towards the back, and inside the bulge, at the bottom of the inside of the helmet, there is an upward-facing recess, which houses the Bluetooth module. In addition, the lower edges of the left and right sides of the outside of the helmet have roughly triangular mounting parts, and a removable triangular cover is provided. These triangular covers can be removed from the mounting parts, and units with operation buttons and antennas of a similar shape can be attached to the mounting parts.

[0005] Furthermore, there is an acoustic device for helmets disclosed in Patent Document 1. This acoustic device attenuates noises such as wind noise, engine noise, exhaust noise, and road noise that occur when riding a motorcycle, as shown in the graph in Figure 11 of Patent Document 1. When stopped at an intersection or parking lot, it is an acoustic signal processing device configured to allow conversation with other riders, as shown in Figure 10 of Patent Document 1. Specifically, speakers are provided near both ears, and the noise detected by the microphone has its phase inverted, while the voice is amplified in phase and emitted from the speakers, thereby achieving both noise attenuation and voice conversation support.

[0006] Here, the microphone for detecting external sounds in this acoustic signal processing device is positioned at or near the lower edge of the helmet, and more preferably on the outer surface of the helmet. In this case, a time difference in sound transmission occurs between the microphone and the speaker located inside the helmet near the ear, but a time delay of several milliseconds to several tens of microseconds is created, thereby reducing the phase shift required for sound generation processing.

[0007] Furthermore, there is a helmet acoustic device disclosed in Patent Document 2. This helmet acoustic device is an exciter, and the case housing the magnetic circuit and voice coil is provided with a concave curved surface that conforms to the outer curved surface of the helmet. The concave curved surface is provided on the surface of a base plate, and the base plate is fitted into one end of the voice coil and becomes one with it. The magnetic circuit including a permanent magnet is fixed inside the case, and the voice coil is held in place by a damper fixed to the inner surface of the case.

[0008] This concave surface allows for easy and secure attachment of the vibration-type sound generator to the outer curved surface of the helmet, and also enables the acquisition of satisfactory bass frequencies. By attaching one vibration-type sound generator, which handles the bass frequencies, to the lower center of the back of the helmet, and two piezoelectric sound generators, which handle the mid-to-high frequencies, to the helmet's visor (shield), excellent musical characteristics can be achieved across the entire frequency range. Here, the vibration-type sound generator was used to enhance the bass frequencies, but it can also be used for the entire frequency range, although its high-frequency performance is inferior. In this case, two LR vibration-type sound generators should be attached to the lower left and right sides of the helmet.

[0009] Furthermore, there is another helmet acoustic device, disclosed in Patent Document 3, which was developed by the same applicant as the present invention. This helmet acoustic device is configured to generate sound by vibrating the helmet, with exciters placed on the left and right sides of a horizontal housing attached to the back of the helmet. The two exciters on the back indirectly vibrate the part of the helmet next to the ears, and the sound generated by this vibration reaches the ears, making it easier to hear ambient sounds and external noises. It also has the advantage of eliminating the need to place speakers near the ears, thus freeing the wearer from the annoyance of speakers touching their ears. [Prior art documents] [Non-patent literature]

[0010] [Non-Patent Document 1] SRL catalog, accessed January 29, 2022, Internet (URL: https: / / senabluetooth.jp / global-image / units / upfiles / sena-SRL_detail.pdf) [Non-Patent Document 2] NEOTEC (registered trademark) 2, [Retrieved January 29, 2022], Internet <URL: https: / / www.shoei.com / contact / rider / catalog / NEOTEC%20II_web_20201001.pdf> [Patent Documents]

[0011] [Patent Document 1] Patent No. 6124203 [Patent Document 2] Japanese Patent Publication No. 2008-236637 [Patent Document 3] Japanese Patent Publication No. 2021-188169 [Overview of the project] [Problems that the invention aims to solve]

[0012] However, in the technology described in Non-Patent Document 1, when this sound device was attached to the motorcycle helmet described in Non-Patent Document 2, the speaker cover was constantly in contact with the ear, causing discomfort due to pressure on the ear. When traveling long distances on highways or other roads on a motorcycle, the ear pressure would continue for extended periods, causing significant discomfort to the user.

[0013] Furthermore, as described in Non-Patent Literature 2, depending on the volume setting, ambient sounds may become inaudible, requiring volume adjustment. This is because the sound is generated by a speaker located near the ear, and since that sound reaches the ear directly, the masking effect makes it difficult to hear ambient sounds, such as external noises. In this case, there was a risk of inconvenience such as difficulty hearing emergency sounds like the sirens of emergency vehicles. Furthermore, the speakers used in this sound system were small in diameter, which presented the disadvantage of having difficulty reproducing low frequencies.

[0014] Furthermore, the technology described in Patent Document 1, like the technology described in Non-Patent Document 1, involves attaching speakers near each ear, which has the disadvantage of the speakers pressing against the ears. In addition, the microphone of the acoustic signal processing device is attached to the lower edge of the helmet, etc., but in this case, the exact position of the microphone on the lower edge, etc., varies from person to person, causing the front-to-back positional relationship to change. This changes the distance between the ear and the microphone, and since a change in distance changes the time difference in sound transmission, it is difficult to adequately correct for phase shift, which is a disadvantage.

[0015] Furthermore, as shown in the graph in Figure 11 of Patent Document 1, high-speed driving generates significant noise, including wind noise components with peaks at several hundred Hz and engine noise, road noise, and exhaust noise components with peaks at several kHz. To attenuate the low-frequency sounds of this wind noise component, it is necessary to generate a sound with inverted phase using a speaker, but small-diameter speakers have difficulty reproducing low frequencies. In other words, in practice, it is necessary to use a large-diameter speaker housed in a speaker box capable of reproducing low frequencies. However, there was a drawback in that it was difficult to install such a large speaker with a speaker box inside a helmet.

[0016] Furthermore, the technology described in Patent Document 2 has the disadvantage that, as described in Patent Document 2, when vibration-type sound generators are attached to the left and right sides and used for the entire frequency range, the high-frequency performance is inferior. Also, as shown in Figures 7 and 8 of Patent Document 2, the vibration-type sound generators protrude from the left and right sides, which becomes a problem when the motorcycle is actually driven, especially at high speeds. In other words, the sides of the helmet are the parts that are directly hit by the wind, and this protrusion causes the inconvenience of generating a lot of wind noise.

[0017] In addition, as shown in FIGS. 7 and 8 of Patent Document 2, the vibration-type acoustic generator is mounted at the lower part of the left and right side surfaces near the ears. Since the helmet at the position near the ears is directly vibrated by the vibration-type acoustic generator, it is difficult to transmit external sounds near the ears, and there is a problem that external sounds are difficult to hear. In addition, the side surface portion of the helmet is a strong and difficult-to-vibrate portion, and in order to obtain a satisfactory bass range at this position, it is necessary to use a large vibration-type acoustic generator. In this case, it protrudes greatly from the left and right side surfaces of the helmet, and there is a problem in safety.

[0018] In addition, in the technique described in Patent Document 3, since the acoustic device for a helmet is attached to the back of the helmet, unlike the case where it is on the side surface of the helmet, there are few problems such as the generation of wind noise by the exciter, but there is a problem that it does not deal with noise such as general wind noise generated during motorcycle running.

[0019] An object of the present invention is to provide a helmet acoustic device that can solve specific problems that occur when a motorcycle is running and can allow the motorcycle to be run comfortably so that sound can be heard while wearing a motorcycle helmet.

Means for Solving the Problems

[0020] In order to solve the above problems, the present invention employs the following configuration.

[0021] The present invention relates to a helmet acoustic device that is attached to and used with a motorcycle helmet. The acoustic device for a helmet includes an acoustic device main body that generates a drive signal, a vibration-type acoustic generator that is connected to the acoustic device main body by a connection cable and vibrates the helmet, and a housing that houses the vibration-type acoustic generator. It has two vibration-type acoustic units, and the two vibration-type acoustic units are respectively fixed to the left and right side surfaces of the outer surface of the helmet. Each vibration-type acoustic generator generates vibration by a drive signal, and the vibration causes the helmet to vibrate, thereby generating sound. The acoustic device main body is configured to be communicable with a portable terminal. The acoustic device main body generates a drive signal based on an acoustic signal of music from the portable terminal, and the vibration-type acoustic unit is driven to play music inside the helmet. In the vibration-type acoustic unit, an external sound microphone is housed near the vibration-type acoustic generator in the housing. The external noise is detected by the external sound microphone, signal-processed by the acoustic device main body, and an acoustic signal with the phase of the external noise inverted is combined with the acoustic signal of music when music is being played, generating a drive signal. Thereby, the vibration-type acoustic unit is driven to cancel noise inside the helmet.

[0022] Also, the two vibration-type acoustic units are respectively fixed to the lower edge portions of the outer surfaces of the left and right side surfaces of the helmet.

[0023] Also, the vibration-type acoustic generator and the external sound microphone are housed in the respective housings in positions arranged substantially front and rear with respect to the traveling direction of the motorcycle.

[0024] Also, the rated input of the vibration-type acoustic generator is 1 watt or less and 0.3 watt or more.

[0025] Also, the acoustic device for a helmet has a voice microphone connected to the acoustic device main body by a connection cable. Using the voice microphone and the vibration-type acoustic unit, the user can make a call through a portable terminal configured to be communicable with the acoustic device main body or through the acoustic device main body.

[0026] Furthermore, the helmet has an upward-facing storage recess on the inner bottom of the rear, and at least a portion of the housing of the sound device is configured to be stored in the storage recess and mounted.

[0027] Furthermore, the helmet has roughly triangular mounting sections on the lower edges of the outer surfaces of the left and right sides, and the vibration-type acoustic unit has a similar roughly triangular shape and is configured to be attachable to the mounting sections.

[0028] Furthermore, the housing of the sound device is characterized by having a bottom portion of a predetermined thickness that covers and seals the opening of the storage recess, with an area larger than the opening, and a bulging portion that protrudes upward from the top surface of the bottom portion and is housed in the storage recess, and a power receiving coil for wireless charging is provided in the bottom portion.

[0029] Furthermore, the sound device body is configured to be installed with at least a portion of it stored in a storage recess, and has a connection connector that supplies power for charging to the battery inside the sound device body, the connection connector protruding from the lower edge of the helmet, and is configured to be oriented approximately laterally with respect to the mounting surface when the bottom of the helmet is placed down.

[0030] Furthermore, the helmet acoustic device is characterized in that, if the external noise detected by the external sound microphone is above a predetermined volume level, it interrupts noise cancellation or interrupts the phase inversion of the approximate frequency range of the emergency sound.

[0031] Furthermore, the helmet acoustic device is configured to lower the volume of music playback or interrupt playback if music playback is in progress, in the event that an emergency sound detected by the external sound microphone exceeds a predetermined volume level. [Effects of the Invention]

[0032] According to the present invention, having the above-mentioned features, it becomes possible to do the following.

[0033] A helmet sound device for use attached to a motorcycle helmet, the helmet sound device has a sound device body that generates a drive signal, and two vibration-type sound units connected to the sound device body by a connecting cable, each comprising a vibration-type sound generator that vibrates the helmet and a housing that houses the vibration-type sound generator, the two vibration-type sound units are fixed to the left and right sides of the outer surface of the helmet respectively, and each vibration-type sound generator generates vibrations in response to the drive signal, and sound is generated by the vibration of the helmet, the sound device body is configured to communicate with a mobile terminal, and the sound device body generates a drive signal in response to a music sound signal from the mobile terminal, driving the vibration-type sound units to play music inside the helmet, each vibration-type sound unit has an external sound microphone housed in the housing near the vibration-type sound generator, external The system is configured such that external noise is detected by an external microphone, and the acoustic device itself processes the signal to invert the phase of the external noise, creating an acoustic signal. If music is being played, this signal is combined with the music's acoustic signal to generate a drive signal, which drives an excitation-type acoustic unit. This unit is configured to perform noise cancellation inside the helmet. Since the excitation-type acoustic generator and the external microphone are located on the same outer surface of the helmet and are roughly at the same distance from the ears, the external noise captured by the external microphone is inverted, and the excitation-type acoustic generator vibrates the helmet to generate a sound that inverts the noise. This makes it possible to cancel external noise, reducing wind noise, engine noise, exhaust noise, road noise, and other noises that occur when riding a motorcycle, allowing riders to enjoy clear music and ride comfortably.

[0034] Furthermore, since the two vibration-type acoustic units are fixed to the lower edges of the outer surfaces of the left and right sides of the helmet, it is possible to effectively vibrate the inner surface of the helmet on each ear side, thereby generating good sound. In other words, the inventors discovered that the lower edges of the sides of the helmet are a part of the helmet's structure that is easily vibrated with a large amplitude. When this lower edge is vibrated using the vibration-type acoustic generator, the vibration is transmitted, and the inner surface of the shell on the ear side vibrates as a diaphragm, generating sound. Here, the inner surface of the helmet on the ear side is a curved surface with a roughly circular arc towards the inside, and is structured in such a way that sound is easily concentrated towards each ear. In addition, since the vibration-type acoustic generators are positioned offset from the sides of the ears, they do not obstruct external sounds from passing through the helmet, resulting in the effect of making it easier for the user to hear external sounds. Furthermore, since the lower edge is a place that is easily vibrated, it is possible to use a small vibration-type acoustic generator, which allows for miniaturization of the vibration-type acoustic unit, and this helps in reducing wind noise due to the shape of the vibration-type acoustic unit.

[0035] Furthermore, since the vibration-type sound generator and external microphone are housed within their respective left and right housings, positioned approximately front-to-back relative to the direction of travel of the motorcycle, it is possible to reduce the area that protrudes from the left and right sides of the helmet's outer surface when viewed from the direction of travel of the motorcycle. This reduces wind resistance during motorcycle riding and decreases wind noise. In other words, when riding a motorcycle, a large amount of wind blows directly onto the helmet. If the vibration-type sound unit were fixed to the side of the helmet, which is most susceptible to this wind, and configured to generate sound to cancel noise during riding, it would be problematic if the vibration-type sound unit itself generated a large amount of wind noise, defeating the purpose of noise cancellation. However, by positioning one of the vibration-type sound generator and external microphone downwind of the other, wind resistance is reduced, and wind noise can be reduced.

[0036] Furthermore, the rated input of the vibration-type sound generator is 1 watt or less and 0.3 watts or more, so even when it is small and installed on the side of a helmet, it produces little wind noise and has enough power to generate sufficient sound pressure.

[0037] Furthermore, the helmet-mounted sound system has a microphone connected to the main unit of the sound system via a connecting cable. Using the microphone and a vibration-type sound unit, the user can communicate with a mobile terminal configured to communicate with the main unit of the sound system, or communicate via the main unit of the sound system. Therefore, in addition to enjoying music and other sounds with the helmet-mounted sound system, users can also enjoy making phone calls.

[0038] Furthermore, the helmet has an upward-facing storage recess at the inner bottom of the rear, and at least a part of the housing of the sound device can be stored in the storage recess and attached. For example, as disclosed in Non-Patent Document 2, at least a part of the housing of the sound device can be stored in the storage recess that incorporates and stores a communication device such as a Bluetooth module of the sound device located at the inner bottom of the rear of the helmet. This reduces the amount of the sound device protruding from the bottom of the helmet and allows the sound device to be securely fixed to the helmet.

[0039] Furthermore, the helmet has roughly triangular mounting sections on the lower edges of the outer surfaces of the left and right sides, and the vibration-type acoustic unit has a similar roughly triangular shape and is configured to be attached to the mounting sections. For example, on a helmet that has roughly triangular mounting sections on the lower edges of the left and right sides of the outer surface for attaching the operation buttons and antenna unit of the acoustic device, as disclosed in Non-Patent Document 2, the vibration-type acoustic unit equipped with a vibration-type acoustic generator can be attached to each section perfectly and without any discomfort. In addition, the original intercom device's speakers become unnecessary, eliminating the need for attachment and the inconvenience of the speakers touching the ears.

[0040] Furthermore, the housing of the sound device has a bottom portion of a predetermined thickness that covers and seals the opening of the storage recess, with an area larger than the opening, and a bulge portion that bulges upward from the top surface of the bottom portion and is housed in the storage recess. A power receiving coil for wireless charging is provided in the bottom portion, so that the helmet can be charged in a stable position without having to change the orientation of the helmet.

[0041] Furthermore, the main unit of the sound device is configured to be installed with at least a part of it stored in a recessed storage area, and has a connection connector that supplies power for charging to the battery inside the main unit of the sound device. The connection connector protrudes from the lower edge of the helmet, and is configured to be oriented approximately laterally with respect to the surface on which the helmet is placed when the bottom of the helmet is facing down. As a result, even when the helmet is placed with the bottom of the helmet facing down with the connection plug inserted into the connection connector, it is possible to charge the helmet while it is in a stable position.

[0042] Furthermore, the helmet-mounted acoustic device is configured to interrupt noise cancellation or interrupt the phase inversion of the approximate frequency range of the emergency sound if the external noise detected by the external sound microphone exceeds a predetermined volume. This makes it possible to hear emergency sounds, such as when an emergency vehicle approaches, without noise cancellation, allowing for a more comfortable motorcycle ride.

[0043] Furthermore, the helmet-mounted acoustic device is configured to either lower the volume of music playback or interrupt playback if an emergency sound detected by the external sound microphone exceeds a predetermined volume level. This allows riders to hear emergency sounds, such as those of approaching emergency vehicles, without them being interrupted by music playback, thus enabling a more comfortable motorcycle riding experience. [Brief explanation of the drawing]

[0044] [Figure 1]This is a perspective view showing the configuration of a helmet acoustic device according to the first embodiment of the present invention. [Figure 2] This is a perspective view showing the helmet acoustic device according to the first embodiment of the present invention when it is attached to a helmet. [Figure 3] This is a perspective view showing an example of use of a helmet acoustic device according to the first embodiment of the present invention. [Figure 4] The main components of the acoustic device for a helmet according to the first embodiment of the present invention are shown, with (A) being a perspective view from the rear and (B) being a perspective view from the front. [Figure 5] The main components of the acoustic device for a helmet according to the first embodiment of the present invention are shown, with (A) being a reference perspective view from the surface direction, (B) being a front view, and (C) being a rear view. [Figure 6] The main components of the acoustic device for a helmet according to the first embodiment of the present invention are shown, with (D) being a bottom view, (E) a left side view, (F) a right side view, and (G) a reference perspective view from the back. [Figure 7] This is an exploded perspective view showing the configuration of the main parts of a helmet acoustic device according to the first embodiment of the present invention. [Figure 8] The main components of the acoustic device for a helmet according to the first embodiment of the present invention are shown, with (A) being a cross-sectional view seen from the front and (B) being a cross-sectional view seen from the bottom. [Figure 9] The main components of the acoustic device for a helmet according to the first embodiment of the present invention are shown, where (A) is a reference perspective view from the front, (B) is a reference perspective view from the back, and (C) is an exploded perspective view. [Figure 10] This is a block diagram showing the circuit configuration of a helmet acoustic device according to the first embodiment of the present invention. [Figure 11] This is a partial cross-sectional view from the front showing the positional relationship of the main parts of the helmet acoustic device according to the first embodiment of the present invention when in use. [Figure 12] This graph shows the frequency characteristics at the mounting position of the main part of the helmet acoustic device according to the first embodiment of the present invention to the helmet. [Figure 13] This is a flowchart showing the operation of a helmet acoustic device according to the first embodiment of the present invention. [Figure 14] This is a perspective view showing the state when the helmet acoustic device according to the second embodiment of the present invention is attached to a helmet. [Figure 15] This is a perspective view showing an example of use of a helmet acoustic device according to a second embodiment of the present invention. [Figure 16] This is a three-view drawing showing the configuration of the main parts of a helmet acoustic device according to a second embodiment of the present invention. [Figure 17] The main components of the acoustic device for a helmet according to the second embodiment of the present invention are shown, with (A) being a cross-sectional view seen from the top and (B) being an exploded perspective view seen from the back. [Figure 18] This is a perspective view showing an example of use of a helmet acoustic device according to a third embodiment of the present invention. [Figure 19] The main components of the helmet acoustic device according to the fourth embodiment of the present invention are shown, with (A) being a perspective view from below and (B) being a bottom view. [Figure 20] The image shows the state when the helmet acoustic device according to the fifth embodiment of the present invention is attached to a helmet, with (A) being a partial perspective view from the rear and (B) being a partial rear view. [Modes for carrying out the invention]

[0045] Embodiments of the present invention will be described in detail below with reference to the drawings. In the following explanation, the forward / backward, up / down, and left / right directions refer to the view from the user's perspective when the user is wearing a helmet equipped with a helmet sound device on their head. The direction in which the user's face is located is called the forward direction, the opposite direction is called the backward direction, the left side of the user's face is called the left direction, and the opposite direction is called the right direction. However, the forward / backward, up / down, and left / right directions shown below are for illustrative purposes only, and this technology is not limited to these directions.

[0046] (First Embodiment) The first embodiment of the helmet sound device 1 (helmet sound device) will be described with reference to Figures 1 to 13. Figure 1 is a perspective view showing the configuration of the helmet acoustic device 1, Figures 2 and 3 are perspective views showing its mounting method and usage examples, Figures 4(A) and 4(B) are perspective views showing the configuration of the main part, Figures 5 and 6(A) through (G) are diagrams that stylistically represent the external shape of the main part, and Figure 7 is a perspective exploded view of the main part. Furthermore, Figures 8(A) and 8(B) are cross-sectional views of the main part, Figures 9(A) and 9(C) are perspective views and perspective exploded views of the main part, Figure 10 is a circuit block diagram, Figure 11 is a partial cross-sectional view showing the positional relationship of the main part during use, Figure 12 is a graph showing its frequency characteristics, and Figure 13 is a flowchart showing its operation.

[0047] As shown in Figure 1, the helmet acoustic device 1 of this embodiment has an acoustic device main unit 2 (acoustic device main unit) having an acoustic device body 3 and a mounting adapter 4, two acoustic units 5, 5 (vibration-type acoustic units) and a microphone unit 6 (voice microphone). The acoustic units 5, 5 and the microphone unit 6 are connected to the acoustic device main unit 2 via waterproof connectors 22, 22, 22 and connection cables 21, 21, 21 (connection cables), respectively.

[0048] As shown in Figure 2, the motorcycle helmet 1000 of this embodiment is a full-face helmet that completely covers the head from the top of the head to the chin, providing high safety. The helmet 1000 has a hard outer shell 1100, a shield 1200 that is rotatably configured relative to the shell 1100, and an impact-absorbing liner 1300 located inside the shell 1100. The shell 1100 is made of a hard material such as fiber-reinforced plastic and plays a role in dispersing and absorbing impacts caused by falls, etc. The shield 1200 is made of a transparent resin, etc., and prevents wind, dust, insects, etc. from entering while riding. The impact-absorbing liner 1300 is made of polystyrene foam, etc., and plays a role in absorbing impacts by being compressed against the head and the shell 1100 in the event of a fall, etc. Although the helmet 1000 also has interior lining and a chin strap, etc., these are omitted from Figure 2.

[0049] As shown in Figure 2, the main acoustic device unit 2 is fixed to the lower part of the outer surface of the rear of the helmet 1000, the acoustic units 5, 5 are fixed to the lower edges of the outer surfaces of the left and right sides, and the microphone unit 6 is fixed to the inner surface of the chin area. The connecting cables 21, 21, 21 and the waterproof connectors 22, 22, 22 are attached so as to be sandwiched between the shell 1100 and the impact-absorbing liner 1300 located inside it.

[0050] Figure 3 shows a situation in which user U, wearing a helmet 1000 equipped with a helmet sound device 1, listens to music and makes calls via a mobile device S (mobile terminal) such as a smartphone while riding a motorcycle. In other words, the helmet sound device 1 is configured to be able to connect wirelessly, such as via Bluetooth®, to the mobile terminal S possessed by user U. User U can operate the mobile terminal S to send sound signals to the helmet sound device 1 and control the helmet sound device 1.

[0051] Figures 4(A) and 4(B) show the sound device main unit 2 with the sound device main unit 3 removed from the mounting adapter 4. Figure 4(A) is a perspective view from the rear, and Figure 4(B) is a perspective view from the front. As shown in Figures 4(A) and 4(B), the sound device main unit 3 has a watertight sound device main unit case 31 that is a box-shaped, roughly rectangular box with a predetermined thickness. The lower part of the rear side bulges outwards towards the rear, and a connection operation section 32 is formed on the bottom surface. The connection operation section 32 has an external volume microphone hole 33, a power button 34, and a connection connector 35 (connection connector) arranged from left to right. An external volume microphone 81, which will be described later, is housed watertight inside the external volume microphone hole 33. In addition, a communication indicator 36 and a charging indicator 37 are arranged on the left and right sides of the bulge at the lower rear side. These communication indicator 36 and charging indicator 37 are placed on the bulge to make them easily visible from the outside.

[0052] As shown in Figure 4(B), the acoustic device body 3 has a square, protruding engagement portion 38 in the center of its inner surface, and engagement protrusions 39, 39, 39, 39 are formed at the four corners of the engagement portion 38, protruding in the left-right direction. In addition, connecting cables 21, 21 are routed to the outside in a watertight manner via waterproof gaskets from the lower left and right ends of the inner surface.

[0053] As shown in Figures 4(A) and 4(B), the mounting adapter 4 is formed in a horizontally elongated rectangle with an outer shape the same size as the sound device body 3, and has a square recessed engaging portion 41 in the center of its outer surface. Engaging protrusions 42, 42, 42, 42 are formed at the four corners of the engaging portion 41, protruding inwards from the recess in the left-right direction, and an engagement lock 43 is provided on the upper left side of the engaging portion 41. To engage the sound device body 3 with the mounting adapter 4, the engaging portion 38 is pressed against the engaging portion 41, slightly shifting it upwards, and then pushed downwards, engaging the adapter by engaging the lock 43. To remove the sound device body 3 from the mounting adapter 4, the engagement lock 43 is released by pressing it to the left, and the sound device body 3 is removed by slightly pushing it upwards.

[0054] As shown in Figures 4(A) and 4(B), cable notches 44, 44 are provided on the lower surfaces of the left and right ends of the outer surface of the mounting adapter 4, allowing the connecting cables 21, 21 to be routed to the outside when engaged. The front side of the mounting adapter 4 has a helmet mounting surface 45 which is a curved surface that roughly matches the shape of the lower back of the helmet 1000, and double-sided adhesive tape 46 for the mounting adapter is attached to the helmet mounting surface 45. In other words, the mounting adapter 4 is configured to be attached to the lower back edge of the helmet 1000 by the double-sided adhesive tape 46 for the mounting adapter.

[0055] The reason the sound device main unit 2 is separated into two parts, the sound device main unit 3 and the mounting adapter 4, is to enable charging of the sound device main unit 3 on its own. In other words, by removing the waterproof connectors 22, 22, 22 and detaching it from the mounting adapter 4, the sound device main unit 3 can be easily separated from the large helmet 1000 and charged. Of course, it is also possible to prepare multiple mounting adapters 4, each having a helmet mounting surface 45 that roughly matches the curved shape of the lower rear edge of helmets 1000 of different sizes.

[0056] Figures 5(A) to (C) and 6(D) to (G) show the detailed external shape of the acoustic unit 5 in an architectural style. Specifically, Figures 5(A) to (C) and 6(D) to (G) show the acoustic unit 5 from the external perspective, front view, rear view, bottom view, left side view, right side view, and internal perspective view, respectively. Here, Figure 6(D) shows the bottom view, but the top view has a similar shape. Figure 7 is an exploded view of the acoustic unit 5 as seen from the external perspective, Figure 8(A) is the A-A section in Figure 5(B), Figure 9(B) is the B-B section in Figure 5(B), and Figures 9(A) to (C) show perspective views and exploded views of the main components used in the acoustic unit 5. Now, let's explain the structure of the acoustic unit 5 using Figures 5 through 9.

[0057] As shown in Figures 5(A) to (C) and Figures 6(D) to (G), the acoustic unit 5 has a so-called streamlined shape with a pointed front, and is roughly box-shaped with an outer surface 51 (housing) and an inner surface 52 (housing) that are vertically symmetrical and horizontally elongated. As shown in Figure 6(D), the outer surface 51 is formed as a gently curved surface that bulges towards the center, and a connection cable hole 53 for connecting a connection cable 21 is provided at the rear edge. Also, as shown in Figures 5(A) and (B), an external sound microphone hole 54 is provided at the rear of the outer surface 51.

[0058] As shown in Figures 7 and 8(A)(B), the acoustic unit 5 houses an exciter 7 (vibration-type acoustic generator) and an external sound microphone 82 (external sound microphone) inside, arranged in a roughly front-to-back direction relative to the direction of travel of the motorcycle, at a predetermined distance apart. The connecting cable 21 is attached via a waterproof cable bush 55, and the outer surface 51 and inner surface 52 are fixed with screws via a thin rubber-like waterproof packing sheet 56, thus forming a watertight structure. The acoustic unit 5 also has a skirt portion 57 made of a flexible material such as urethane rubber, and the outer surface of the inner surface 52 is fixed to the outer surface of the helmet 1000 via waterproof double-sided adhesive tape 58 for acoustic units. Here, the skirt portion 57 has a curved surface that is continuous with the curved surface of the outer surface 51, allowing the air hitting the helmet 1000 to flow smoothly to the rear, and due to its flexible material, it does not hinder the transmission of vibrations from the acoustic unit 5 to the helmet 1000.

[0059] Here, the acoustic unit 5 houses the exciter 7 and the external sound microphone 82 in an approximately front-to-back direction relative to the direction of travel, thus reducing the area that protrudes from the left and right sides of the outer surface of the helmet 1000 when viewed from the front. Incidentally, when riding a motorcycle, a large amount of wind blows directly onto the helmet 1000. The acoustic unit 5 is fixed to the side of the helmet, which is most likely to receive this wind, and is configured to generate sound to cancel out noise while riding. However, if the acoustic unit 5 itself generates a large amount of wind noise, it defeats the purpose of noise cancellation. Therefore, as one countermeasure, the external sound microphone 82 is configured to be positioned downwind of the exciter 7, thereby reducing wind resistance and significantly reducing wind noise. The same applies when the exciter 7 is positioned downwind of the external sound microphone 82, and this case is also included in the description of the approximately front-to-back direction.

[0060] As shown in Figures 7 and 8(A)(B), an exciter mounting recess 59 is formed on the inner surface of the inner surface 52 for mounting the exciter 7 in a predetermined position, and the exciter 7 is fixed therein. The external sound microphone hole 54 is sealed watertight from the inside with a waterproof sheet 83. The waterproof sheet 83 is a membrane that allows air to pass through but not water, providing waterproofing while preventing sound from being muffled. The inside of the waterproof sheet is formed in a roughly cylindrical shape, and a windproof foam material 84 for the windscreen and the external sound microphone 82 are fixed therein. The external sound microphone 81 inside the external sound microphone hole 33 of the sound device body 3 and the voice microphone 85 housed in the microphone unit 6 have the same configuration as the external sound microphone 82 and are each fixed in a watertight manner.

[0061] Here, the configuration of the exciter 7 used in this acoustic unit 5 will be explained using Figures 9(A), 9(B), and 9(C). Figure 9(A) is a perspective view of the exciter 7 from the front, Figure 9(B) is a perspective view from the back, and Figure 9(C) is an exploded view of the exciter 7 in a perspective view from the front.

[0062] As shown in Figures 9(A), (B), and (C), the exciter 7 has an exciter frame 71 with a roughly rectangular shape and a hollow section in the center. In the center of this hollow section is a cylindrical vibration transmission section 72 with a roughly closed bottom and a hole at the bottom, which is held in a vibratory position by four roughly S-shaped dampers 73, 73, 73, 73. The closed bottom portion at one end of the vibration transmission section 72 protrudes to the outside of the hollow section, and an exciter adhesive tape 74 is attached to the outer surface of this closed portion. The exciter frame 71, vibration transmission section 72, and dampers 73, 73, 73, 73 are all made of a single piece of resin.

[0063] As shown in Figure 9(C), a cylindrical coil 75 is fitted onto the cylindrical outer surface of the other end of the vibration transmission section 72 and fixed with adhesive or the like. Both terminals of the coil 75 are connected to terminal plates 76, 76. The exciter 70, like other exciters, has a bottomed cylindrical yoke 77 and a cylindrical permanent magnet 78 that form a magnetic circuit, and the coil 75 is held so as to be located in the gap between the inner surface of the cylindrical part of the yoke 77 and the outer surface of the permanent magnet 78. When driving power is supplied to the coil 75 from the terminal plates 76, 76, the coil 75 moves back and forth in the gap between the yoke 77 and the permanent magnet 78, and the vibration transmission section 72 held by the four dampers 73, 73, 73, 73 starts to vibrate.

[0064] Here, as shown in Figures 8(A) and 8(B), the exciter 7 is fixed to the exciter mounting recess 59 on the inner surface of the inner surface 52 of the acoustic unit 5. Therefore, when the vibration transmission part 72 vibrates, the vibration is transmitted to the shell 1100 to which the inner surface 52 is fixed. As a result, sound is indirectly generated by the vibration of the shell 1100 of the helmet 1000, and this sound is transmitted to the user U.

[0065] Now, let's explain how the helmet acoustic device 1 works using the circuit block diagram shown in Figure 10. As shown in Figure 10, the main unit 3 of the sound device unit 2 has a main board 9 and a battery 86, etc., and the microphone unit 6 has a voice microphone 85. The main board 9 has a control unit 91, the battery 86 is connected to the control unit 91 via a power supply unit 92, and the display unit 93 and the operation unit 94 are connected to the control unit 91 via their respective interfaces.

[0066] As shown in Figure 10, the exciters 7, 7 mounted on the two acoustic units 5, 5 are driven by exciter drive units 95, 95 connected to the control unit 91. The external sound microphones 82, 82 are connected to the control unit 91 via external sound microphone signal processing units 96, 96, respectively. The voice microphone 85 and the external volume microphone 81 are connected to the control unit 91 via the voice microphone signal processing unit 97 and the external volume microphone signal processing unit 98, respectively. The control unit 91 is also connected to a communication unit 99 (communication unit) and is configured to communicate with the mobile terminal S via the communication unit 99.

[0067] In Figure 10, when an external cable (not shown) is connected to the USB connector, which is the connection connector 35, the battery 86 is charged via the power supply unit 92. At this time, an LED (not shown) on the display unit 93 activates and the charging indicator 37 lights up red, and turns off when charging is complete. Furthermore, firmware updates for the control unit 91 can be performed while the external cable is connected to the connection connector 35.

[0068] In Figure 10, when the power button 34, one of the control buttons 94, is pressed and held, the helmet sound device 1 is activated. When the power is turned on for the first time, it automatically enters pairing mode, an LED (not shown) on the display unit 93 activates, and the communication indicator 36 flashes red and blue alternately. The communication unit 99 is configured to enable wireless communication by connecting to the mobile terminal S via Bluetooth®, so once pairing is performed, the connection will be established automatically thereafter. The status of waiting for connection with the mobile terminal S and the connected state are indicated by different blue flashing patterns of the communication indicator 41. Furthermore, while connected to the mobile terminal S, it is possible to perform firmware updates and configure various settings of the helmet sound device 1 using the mobile terminal S.

[0069] Furthermore, as shown in Figure 10, the device includes an accelerometer (not shown) as the operating unit 94, allowing users to tap the surface of the helmet's acoustic device 1 or the helmet 1000 with their palm. For example, when a call comes in, one tap allows the user to answer the call, and another tap hangs up. Tapping twice activates a voice assistant such as Siri® or Google Assistant®.

[0070] In Figure 10, the external sound microphone 81 is for the automatic volume control function. That is, once the volume is initially adjusted using the mobile terminal S with the exciter 7, the system is configured to automatically adjust the volume according to the volume of ambient noise, increasing when the noise level is high and decreasing when it becomes quiet. In this embodiment, an external sound microphone 81 is provided, but the external sound microphone 81 may be omitted by obtaining the external sound volume using the external sound detected by the two external sound microphones 82, 82.

[0071] In Figure 10, the voice microphone 85 is for capturing the voice of user U during phone calls, etc. Here, as shown in Figure 3, the voice microphone 85 is positioned slightly away from the mouth. The inventors have confirmed that even when positioned slightly away from the mouth, the microphone can adequately capture the voice of user U, as long as it is not a highly directional microphone. Of course, it is also possible to position the voice microphone 85 closer to the mouth.

[0072] In Figure 10, the external sound microphones 82, 82 are for detecting noise generated when the motorcycle is in motion. That is, as shown in the graph of Figure 11 of the aforementioned Patent Document 1, when driving at high speeds, a large amount of noise is generated, including wind noise components with a peak at several hundred Hz, and engine noise, road noise, and exhaust noise components with peaks at several kHz. Moreover, when driving on a highway, for example, this noise continues for a long time.

[0073] External noise is detected by external microphones 82, 82, and the main board 9 processes the signal to create an inverted acoustic signal. If music is being played, this signal is combined with the music signal to generate a drive signal. This drives the exciters 7, 7, causing the helmet 1000 to vibrate and generate sound. Noise cancellation is performed inside the helmet 1000, reducing the noise when riding a motorcycle.

[0074] Here, the acoustic unit 5 is attached to the side of the outer surface of the helmet 1000, and the external sound microphone 82 is housed near the internal exciter 7. Therefore, the exciter 7 and the external sound microphone 82 are on the same outer surface of the helmet 1000, and their distance from the ears is approximately the same. In this configuration, by inverting the external noise captured by the external sound microphone and using the exciter 7 to vibrate the helmet 1000 to generate a sound that inverts the noise, it becomes possible to cancel out external noise. In other words, it becomes possible to reduce noises such as wind noise, engine noise, exhaust noise, and road noise that occur when riding a motorcycle, allowing riders to enjoy clear music and ride the motorcycle comfortably.

[0075] Next, using Figures 11 and 12, we will explain the frequency characteristics depending on the position in which the acoustic unit 5 is attached to the helmet 1000. As shown in Figure 11, measurements were taken with the acoustic unit 5 on the helmet 1000 in two cases: "A. When installed on the lower edge" and "B. When installed next to the ear". Figure 12 shows the measured frequency characteristics for each case. For measuring the frequency characteristics, we used an ear dummy microphone 2000, which was created by embedding a dummy microphone 2200 into an ear dummy 2100, which was molded from an actual human ear and had the auricle and external auditory canal formed from resin, as shown by the hatching in Figure 11.

[0076] As shown in Figure 12, when the device is installed on the lower edge, it produces deep bass frequencies below 100Hz, reduces harsh high frequencies with peaks around 900Hz and 3500Hz, and minimizes the dip around 300Hz, compared to when it is installed beside the ear. In other words, it is possible to generate both low and high frequencies, resulting in a sound that is easier for the user U to listen to, and also enabling effective noise cancellation against wind noise components with peaks at several hundred Hz.

[0077] This is because, by installing the acoustic unit 5 on the lower edge of the helmet 1000, it becomes possible to effectively vibrate the inner surface of the helmet 1000 on the ear side, thereby generating good sound. In other words, the inventors discovered that the lower edge of the side of the helmet 1000 is a part of the helmet 1000's structure that is easily vibrated with a large amplitude. When this lower edge is vibrated using the exciter 7, the vibration is transmitted, and the inner surface of the shell 1100 on the ear side vibrates as a diaphragm, generating sound.

[0078] Here, the inner surface of the helmet 1000 on the ear side is a curved surface with a roughly circular arc inward, creating a structure that easily concentrates sound towards each ear. In addition, the exciters 7 are positioned offset from the sides of the ears, which makes it less likely for external sounds to obstruct the passage of external sounds through the helmet 1000, resulting in the effect of making it easier for the user to hear external sounds. In other words, instead of producing loud sounds right next to the ears, the sound generated by the vibrations transmitted to the shell 1100 is, when actually listened to, an enveloping sound, similar to the sound heard through speakers in a room.

[0079] Furthermore, since the lower edge is a place that is easily vibrated, it becomes possible to use a small exciter 7 to generate sound, which allows for miniaturization of the vibration-type acoustic unit, and this helps to reduce wind noise, etc. In other words, attaching the exciter 7 to the lower edge of the shell 1100, which is easily vibrated, also helps to miniaturize the exciter 7 itself.

[0080] For example, in the helmet acoustic device disclosed in Patent Document 3, developed by the same applicant as the present invention, the back of the helmet is vibrated by an exciter, which necessitates the use of a large and powerful exciter. The back shell of the helmet plays an important role in protecting the back of the user's head, and is therefore constructed robustly and is difficult to vibrate; thus, a large and powerful exciter is required to vibrate it.

[0081] In the helmet acoustic device disclosed in Patent Document 3, the exciter used has a rated power handling (Continuous power handling) of 2 watts and a maximum power handling (Burst power handling) of less than 4 watts. In contrast, the exciter 7 used in the present invention has a rated power handling of 0.5 watts and a maximum power handling of less than 1 watt.

[0082] This significantly reduces the portion of the helmet 1000 that protrudes from the sides, helping to reduce wind noise, and also contributes to longer continuous usage time by reducing power consumption. Furthermore, while maintaining the same continuous usage time, it becomes possible to miniaturize the battery 86, and thus the main unit 2 of the sound device.

[0083] An exciter generates sound by vibrating a diaphragm, and therefore, compared to a speaker, it can produce bass frequencies and achieve a higher volume. However, it still requires at least some power to vibrate the diaphragm and generate the desired volume. In other words, if a 2-watt rated input device is installed on the side of the helmet 1000, it will protrude significantly, resulting in a large amount of wind noise. Therefore, a smaller device is preferable, but it also needs enough power to vibrate the shell 1100, which is the diaphragm, and produce a sufficient volume. This means that the rated input of the exciter 7 should be less than half of the 2-watt device, which is 1 watt or less, and ideally 0.3 watts or more.

[0084] Although the mounting position of the acoustic unit 5 on the helmet 1000 was defined as the lower edge of the helmet 1000, this is not limited to mounting the acoustic unit 5 along the lower edge of the helmet 1000. For example, some helmets have a U-shaped bulge covering the lower edge of the helmet with a rubber-like material of a predetermined thickness, in which case it is difficult to mount the acoustic unit 5 along the lower edge. In such cases, it has been confirmed that the unit can be mounted on the part above this rubber-like material, avoiding it, and still be sufficiently effective. In other words, the lower edge of the helmet 1000 refers to the area near the lower edge.

[0085] Here, the noise cancellation function of the helmet acoustic device 1 is configured to respond to emergency sounds such as sirens from police cars and ambulances. Now, let's explain how the helmet acoustic device 1 operates its noise cancellation function using the flowchart in Figure 13.

[0086] As shown in Figure 13, in S01, it is determined whether the detected external sound is above a predetermined volume. If the external sound is above the predetermined volume, the process proceeds to S02, and noise cancellation is activated.

[0087] In S03 of Figure 13, if the emergency sound in the ambient noise exceeds a predetermined volume, the process proceeds to S04, interrupting the noise cancellation operation. Then, in S05, if music is playing, the playback is interrupted. In S06, the counter is reset to zero, and the process proceeds to S07, S08, and S09, where the voice announcement "An emergency vehicle is approaching" is repeated three times only on the first use.

[0088] In S10 of Figure 13, it is determined whether the helmet 1000 or the sound device unit 3 has been tapped. That is, if the user U confirms this, for example, when an emergency vehicle is traveling in the opposite lane, and taps, the process proceeds to S12. If no tap is made, the process proceeds to S11, and if the emergency sound in the external noise is above a predetermined volume, the process returns to S07, where no voice guidance is given, but the current situation is maintained, and when the volume of the emergency sound falls below the predetermined volume, the process proceeds to S12. Then, in S12, noise cancellation is activated, and in S13, music playback resumes. As described above, the helmet acoustic device 1 operates.

[0089] In this configuration, if the detected external sound exceeds a predetermined volume, the noise cancellation will continue to operate from that point onward. However, if the external sound falls below the predetermined volume while noise cancellation is in operation, the noise cancellation operation may be stopped. Furthermore, the determination of whether an emergency sound among the external sounds exceeds a predetermined volume may be performed by the sound device unit 3, or the sound device unit 3 may communicate with the mobile terminal S to perform the determination. If the determination is made by the mobile terminal S, a more detailed and sophisticated determination is possible, while if the determination is made by the sound device unit 3 without communication, a quicker determination is possible.

[0090] As described above, the system is configured to interrupt noise cancellation and music playback in response to emergency sounds. This ensures that emergency sounds are transmitted to the user U without being hindered by noise cancellation or music playback, allowing for a more comfortable motorcycle ride. In this configuration, the noise cancellation function is interrupted by the emergency sound, and music playback is stopped. However, it may also be configured to interrupt the phase inversion in the approximate frequency range of the emergency sound, or to lower the volume of music playback. In this case as well, it is possible to prevent the emergency sound from being prevented from being transmitted to the user U.

[0091] Furthermore, the invention of this embodiment can also be expressed as follows. A helmet acoustic device for use attached to a motorcycle helmet, comprising an acoustic device body that generates a drive signal, and an excitation type acoustic unit fixed to the left and right sides of the helmet that vibrates the helmet in response to the drive signal to generate sound, wherein the acoustic signal obtained by inverting the phase of external noise detected by an external sound microphone in the excitation type acoustic unit is combined with a music acoustic signal to generate sound, thereby canceling out external noise. This configuration allows for noise cancellation of external noises such as wind noise that occur while riding a motorcycle, enabling riders to enjoy music while comfortably riding their motorcycles.

[0092] (Second embodiment) A second embodiment of the present invention will be described with reference to Figures 14 to 17. In this second embodiment, similar to the first embodiment, the helmet acoustic device 1 has an acoustic device main unit 2, two acoustic units 5, 5 and a microphone unit 6, and has the same function. Hereinafter, the same parts as in the first embodiment will be denoted by the same reference numerals and their descriptions will be omitted, and only the different parts will be described.

[0093] Figure 14 is a perspective view showing how the helmet sound device 1 and helmet 1000 are attached in this embodiment, with the helmet 1000 inverted and the sound device main unit 2 and one of the sound units 5 partially removed. Figure 15 is a perspective view showing an example of using the helmet sound device 1, and, as in the first embodiment, the user U can listen to music and make calls via the mobile terminal S while riding the motorcycle. Figure 16 includes a side view and a bottom view of the sound device main unit 3, as well as a view from an oblique direction. Figure 17(A) is a cross-sectional view showing the CC cross section of the sound unit 5 in Figure 14, and Figure 17(B) is a perspective exploded view.

[0094] Here, the motorcycle helmet 1000 used in this embodiment is a full-face helmet having a shell 1100, a shield 1200, an impact-absorbing liner 1300, etc., similar to the first embodiment. However, the mounting configuration for the helmet's acoustic device 1 is significantly different, so this helmet 1000 will be explained using Figures 14 and 15.

[0095] As shown in Figure 14, the helmet 1000 of this embodiment has a configuration similar to the motorcycle helmet described in Non-Patent Document 2, and is configured to allow the intercom device described in Non-Patent Document 1 to be attached. Specifically, the lower edge of the rear of the helmet 1000 is slightly bulged outwards towards the back, and a recess extending upwards from the bottom is provided on its inner surface to form a storage recess 1400 (storage recess). In addition, roughly triangular mounting portions 1500, 1500 (mounting portions) are provided on the lower edges of the left and right sides of the outer surface of the helmet 1000. Around the mounting portions 1500, 1500, mounting portion edges 1600, 1600 are provided that bulge outwards from the outer surface of the shell 1100 toward the mounting portions 1500, 1500. Note that while the helmet in Non-Patent Document 2 has a face cover that can be opened and closed, the helmet 1000 in this embodiment does not have this function. Also, in Figure 14, the connection cable 21 and other components are omitted from the description.

[0096] As shown in Figures 14 and 15, the helmet sound device 1 of this embodiment retains the functions of the first embodiment, and is shaped to fit snugly and comfortably onto a helmet 1000 having a configuration similar to that of Non-Patent Document 2. In other words, as shown in Figure 14, the main unit of the sound device 2 is configured to be mounted in the storage recess 1400 at the inner bottom of the rear of the helmet 1000, and the sound units 5, 5 are configured to be mounted in the mounting parts 1500, 1500 at the lower edges of the left and right sides of the outer surface. In this case, unlike the first embodiment, the sound device main unit 2 does not have a mounting adapter 4 and consists only of the sound device main unit 3.

[0097] As shown in Figure 16, the acoustic device body 3 has an acoustic device body case 31 with a watertight configuration consisting of a bottom case 47 (bottom portion) which is a bottom portion of a predetermined thickness, and a storage portion case 48 (storage portion) which protrudes diagonally upward from the bottom case 47. A connection operation section 32 is formed on the bottom surface of the bottom case 47. The connection operation section 32 has a power button 34, a communication indicator 36, a charging indicator 37, a connection connector 35, and an external volume microphone hole 33 arranged from left to right, and an external volume microphone 81 (not shown) is watertightly housed inside the external volume microphone hole 33. Furthermore, an engagement portion 38 is formed in the center of the front of the bottom case 47, and connection cables 21, 21 are configured to be pulled out to the outside watertightly via waterproof gaskets from the left and right sides of the front.

[0098] As shown in Figures 14 and 16, the storage case 48 for the acoustic device body 3 is housed inside the storage recess 1400, which has an upward-facing recess at the inner bottom of the rear of the helmet 1000. The bottom case 47 is configured to have a larger area than the opening of the storage recess 1400 and is attached in a lid-like manner. The storage recess 1400 of the helmet 1000 also has an engagement part (not shown) for engaging with the Bluetooth module of an intercom device that can be originally installed. When the acoustic device body 3 is installed in this storage recess 1400, the engagement part 38 is configured to detachably engage with this engagement part and be fixed to the helmet 1000.

[0099] The storage case 48 of the sound device body 3 houses electrical components such as a battery 86, which are not shown. This storage case 48 is shaped like an acute triangle with a flattened tip when viewed from the side, to match the shape of the inside of the storage recess 1400 of the helmet 1000, but its shape can be changed in various ways as long as it fits into the storage recess 1400. In addition, the bottom case 47, which has a larger area than the opening of the storage recess 1400, allows for the placement of the power button 34, connection connector 35, and connection operation unit 32 with various displays, making it easy for the user U to use.

[0100] In other words, the structure of the acoustic device body 3 can also be described as follows. A helmet sound device for use attached to a helmet having an upward-facing recess, which is a storage recess, on the inside of the bottom rear of the helmet, wherein the helmet sound device comprises a sound device body that generates a drive signal, and a sound generator connected to the sound device body by a connecting cable and generating sound inside the helmet in response to the drive signal, wherein the sound device body has a bottom surface portion of a predetermined thickness that covers and seals the opening of the storage recess, with an area larger than the opening of the storage recess, and a storage portion that bulges upward from the top surface of the bottom surface and is housed in the storage recess, the storage portion houses at least a battery for driving the helmet sound device, and an operating portion and a display portion are provided on the bottom surface of the bottom surface. Furthermore, by configuring the helmet-mounted acoustic device in this way, it became possible to provide a large operating surface, making it easier for the user U to operate.

[0101] As shown in Figures 14, 15, and 17(A)(B), the acoustic units 5, 5 are configured in a triangular box shape with an outer surface 51 and an inner surface 52 that fit the left and right triangular mounting parts 1500, 1500. That is, the left and right acoustic units 5, 5 are formed in a symmetrical shape so that they can be attached to the left and right mounting parts 1500, 1500. The outer surface 51 has a curved surface that bulges out in the approximate center, continuous with the mounting part edges 1600, 1600, and an external sound microphone hole 54 is provided at the rear.

[0102] As shown in Figures 17(A) and 17(B), the acoustic unit 5 has an outer surface 51 and an inner surface 52 that are fixed together with screws via a thin rubber-like waterproof packing sheet 56, and the connecting cable 21 is routed through a waterproof packing (not shown), thus forming a watertight structure. The acoustic unit 5 is configured such that the outer surface of the inner surface 52 is fixed to the mounting part 1500 via waterproof double-sided adhesive tape 58 for acoustic units. Here, the outer surface 51 of the acoustic unit 5 has a curved surface that is continuous with the bulging curved surface of the mounting part edge 1600, so that the air hitting the helmet 1000 is smoothly directed to the rear.

[0103] As shown in Figures 17(A) and (B), the acoustic unit 5 houses an exciter 7 inside and an external sound microphone 81 nearby, arranged approximately front to back with respect to the direction of travel of the motorcycle. An exciter mounting recess 59 is formed on the inner surface of the inner surface 52 for mounting the exciter 7 in a predetermined position, and the exciter 7 is fixed therein. The external sound microphone hole 54 is sealed watertight from the inside with a waterproof sheet 83, and the inside is formed into a roughly cylindrical shape, to which a windscreen foam material 84 for the windscreen and an external sound microphone 82 are fixed.

[0104] Here, as in the first embodiment, the acoustic unit 5 houses the exciter 7 and the external sound microphone 82 side by side in a direction approximately front to back with respect to the direction of travel, making it possible to reduce the area that protrudes from the left and right sides of the outer surface of the helmet 1000 when viewed from the front. Incidentally, when riding a motorcycle, a large amount of wind blows directly onto the helmet 1000. Even if the acoustic unit 5 is fixed to the side of the helmet, which is prone to being directly exposed to this wind, the external sound microphone 82 is positioned downwind of the exciter 7, so wind resistance is reduced and wind noise can be greatly reduced. The same applies when the exciter 7 is positioned downwind of the external sound microphone 82.

[0105] Furthermore, the acoustic unit 5 is mounted on the side of the helmet 1000's outer surface, and the external sound microphone 82 is housed near the internal exciter 7. Therefore, the exciter 7 and the external sound microphone 82 are on the same outer surface of the helmet 1000, and their distance from the ears is approximately the same. This means that by inverting the external noise captured by the external sound microphone and using the exciter 7 to vibrate the helmet 1000 to generate a sound that inverts the noise, it becomes possible to cancel out external noise. In other words, it becomes possible to reduce noises such as wind noise, engine noise, exhaust noise, and road noise that occur when riding a motorcycle, allowing riders to enjoy clear music and ride comfortably.

[0106] Furthermore, the mounting points 1500, 1500 are located precisely on the lower edges of the outer surfaces of the left and right sides of the helmet 1000. In other words, the two exciters 7, 7 are fixed to the lower edges of the outer surfaces of the left and right sides of the helmet 1000, which allows for effective vibration of the inner surfaces on each ear side of the helmet 1000, resulting in the generation of a good sound.

[0107] Here, the lower edge of the side of the helmet 1000 is a part that is prone to vibrating with a large amplitude, and the exciter 7 is used to vibrate the inner surface of the helmet 1000 on each ear side as a diaphragm, thereby generating sound. The inner surface of the helmet 1000 on the ear side is a curved surface with a roughly circular arc inward, and is configured so that sound is easily concentrated on each ear. In addition, by positioning the exciter 7 a little distance from the ears, the user has the effect of being able to hear external sounds passing through the helmet 1000 more directly. Furthermore, because it is a place that is easily vibrated, it is possible to use a small exciter 7, which helps to reduce wind noise.

[0108] As described above, the helmet sound device 1 of this embodiment is configured such that the sound device body 3 and sound units 5, 5, etc., can be attached to the helmet 1000 used in this embodiment perfectly and without any discomfort. Furthermore, the speakers of the intercom device described in Non-Patent Literature 1 are no longer necessary, eliminating the inconvenience of the speakers touching the ears, and eliminating the need for their installation.

[0109] (Third embodiment) A third embodiment of the present invention will be described with reference to Figure 18. In this third embodiment, the same helmet sound device 1 as in the second embodiment is used, but because the configuration of the helmet 1000 to which it is attached is slightly different, a corresponding arm-equipped microphone unit 61 is used. Hereafter, the same parts as in the first embodiment are denoted by the same reference numerals and their descriptions are omitted, and only the different parts will be described.

[0110] Figure 18 is a perspective view showing an example of the use of the helmet acoustic device 1. Similar to the first and second embodiments, the user U can listen to music and make calls via the mobile terminal S while riding the motorcycle.

[0111] As shown in Figure 18, the helmet 1000 used in this embodiment is not a full-face type like those used in the first and second embodiments, but rather an open-face helmet or jet helmet. An open-face helmet is a helmet that protects the head, ears, and cheeks, and unlike a full-face helmet, it does not have a chin area.

[0112] This open-face helmet has an open chin area, so compared to a full-face helmet, it is less stuffy when worn, can be worn with glasses, and has a wider field of vision. Some helmets have a wind shield, while others do not. In this embodiment, helmet 1000 has a rotatably mounted shield 1200.

[0113] Here, the helmet 1000 of this embodiment has a mounting configuration similar to that of the motorcycle helmet described in Non-Patent Document 2, as in the second embodiment. Specifically, the inner bottom of the rear of the helmet 1000, similar to the second embodiment, has a storage recess 1400 (not shown) with an upward-facing recess, and the lower edges of the left and right sides of the outer surface have roughly triangular mounting portions 1500, 1500.

[0114] Furthermore, in this embodiment, the helmet sound device 1, similar to the second embodiment, allows the sound device main unit 2 to be attached to the storage recess 1400 and the sound units 5, 5 to the mounting parts 1500, 1500. However, since the helmet 1000 does not have a chin portion, the microphone unit 6 cannot be attached as is. Therefore, the arm-equipped microphone unit 61 of this embodiment will be described below.

[0115] As shown in Figure 18, the armed microphone unit 61 has a microphone unit 6 and a voice microphone arm 62. The armed microphone unit 61 used here is the microphone unit 6 itself from the first and second embodiments, attached and fixed to one end of the voice microphone arm 62. That is, one end of the voice microphone arm 62 is formed with a roughly round outer shape and a roughly flat surface, and is configured so that the microphone unit 6 can be fixed to its back surface. The other end of the voice microphone arm 62 is formed with a thin, roughly flat, and roughly rectangular shape via a step toward the inner surface, and is formed with a curved surface that roughly traces a spherical shape so as to conform to the inner surface of the helmet 1000 to which it is attached.

[0116] Here, cheek pads (not shown) are detachably provided on the cheek area of ​​the inside of the helmet 1000. By removing these cheek pads and securing the outer surface of the other end of the voice microphone arm 62 to the inside of the helmet 1000 with hook-and-loop fasteners or double-sided adhesive tape, the microphone unit with arm 61 can be fixed to the helmet 1000. The other end of the voice microphone arm 62 is formed in a thin, almost flat shape, and the installation is completed by attaching the removed cheek pads back to their original position on the inside of the helmet 1000.

[0117] Although the helmet 1000 in this embodiment has been described as an open-face type, it is also compatible with the helmet described in Non-Patent Document 2, which has a face cover that can be opened and closed. In other words, in helmets with a face cover that can be opened and closed, the chin portion moves together with the face cover, so the microphone unit 6 cannot be attached as is. Therefore, by using the voice microphone arm 62 of this embodiment, the microphone unit 61 with an arm can be attached to the helmet, similar to the open-face type helmet 1000 of this embodiment.

[0118] (Fourth embodiment) A fourth embodiment of the present invention will be described with reference to Figures 19(A) and 19(B). In this fourth embodiment, the helmet acoustic device 1 has the same configuration as in the second embodiment, but a part of the acoustic device body 3 of the acoustic device body unit 2 has been modified to make charging easier. Hereafter, the same parts as in the second embodiment will be denoted by the same reference numerals and their descriptions will be omitted, and only the different parts will be described.

[0119] In this case, the helmet sound device 1, which allows the user to hear sounds while wearing the helmet 1000, first needs to be charged to function. While the sound device body 3 can be charged by connecting an external cable, this requires separating it from the helmet 1000 each time. It would be more convenient and easier to handle if the sound device body 3 could be charged while still attached to the helmet 1000. Furthermore, as will be described in detail in the following fifth embodiment, attempting to charge the sound device body 3 using a power supply cable connected to the connector 35, which is located on the bottom surface of the sound device body 3 and facing downwards, results in various inconveniences. Therefore, this embodiment presents a configuration that allows for easy and stable charging of the helmet sound device 1 while it is attached to the helmet 1000, without using a power supply cable.

[0120] Figure 19(A) shows a perspective view of the sound device body 3 of the sound device body unit 2 as seen from the bottom, and Figure 19(B) shows a bottom view of the sound device body 3. As shown in Figures 19(A) and (B), the sound device body 3 of this embodiment has an external shape that is substantially the same as that of the second embodiment and has a bottom case 47 of a predetermined thickness and a storage case 48 that protrudes diagonally upward from the bottom case 47, but the configuration of the connection operation part 32 of the bottom case 47 is different. Here, the sound device main unit 2, as in the second embodiment, does not have a mounting adapter 4 and consists only of the sound device main unit 3.

[0121] Specifically, as shown in Figures 19(A) and 19(B), the connection operation section 32 on the underside of the sound device body 3 has a flat central section of a predetermined area, which bulges downwards. A power button 34, a communication indicator 36, and an external volume microphone hole 33 are located near the left end, while a connection connector 35 and a charging indicator 37 are located near the right end. On the inner surface of the bulging plane of the connection operation section 32, a power receiving coil 87 for the wireless charging system is located, forming a charging bulge 49, which enables wireless charging of the battery 86 housed in the sound device body 3.

[0122] With this configuration, the bottom case 47 of the sound device body 3 is located at the bottom of the helmet 1000 and protrudes downward, so that the sound device body 3 can be attached to the helmet 1000 and charged simply by placing it on a power supply such as a charging pad. In other words, the central part of the connection operation section 32 is made into a flat surface of a predetermined area in order to receive the magnetic field of the power supply coil of the power supply device into the power receiving coil 87 by electromagnetic induction, thereby enabling smooth wireless charging. Of course, in order to align the power receiving coil 87 and the power supply coil of the power supply device, magnets that attract each other may be placed on each, or appropriate protrusions or recesses that engage with each other may be provided.

[0123] Furthermore, it is desirable that this wireless charging system conform to the Qi® standard defined by the Wireless Power Consortium. This is because commercially available power supplies and receiving coils can be used. In order to attach the receiving coil, it is necessary to provide a power receiving section of a predetermined area that is substantially parallel to the mounting surface. This is made possible because the acoustic device body 3 of this embodiment has a bottom case 47 in addition to the storage case 48.

[0124] In other words, the structure of the sound device body 3 of this embodiment can also be described as follows. A helmet sound device for use attached to a helmet having an upward-facing recess, which is a storage recess, on the inside of the bottom rear of the helmet, wherein the helmet sound device comprises a sound device body that generates a drive signal, and a sound generator connected to the sound device body by a connecting cable and generating sound inside the helmet in response to the drive signal, wherein the sound device body has a bottom surface portion of a predetermined thickness that covers and seals the opening of the storage recess with an area larger than the opening of the storage recess, and a bulging portion that bulges upward from the top surface of the bottom surface and is stored in the storage recess, and a power receiving coil for wireless charging is provided on the bottom surface. Furthermore, by configuring the helmet acoustic device in this way, it becomes possible to position the power receiving coil in the bottom case 47 approximately parallel to the mounting surface, and to charge the helmet while it is placed in a stable position without having to change its orientation.

[0125] Here, we will explain how a plane of a predetermined area is made to bulge downward from the lower surface of the acoustic device body 3, thereby forming a charging bulge portion 49. Incidentally, when charging a mobile device such as a smartphone with a built-in power receiving coil using a power supply, the entire mobile device is placed on the top surface of the power supply, so there is no gap between the two and charging is efficient. On the other hand, in the case of the helmet sound device 1, the sound device body 3 is attached to the bottom of the rear of the helmet 1000, and charging is performed by inserting a power supply having a predetermined thickness into the bottom of the rear of the helmet 1000. That is, the front of the helmet 1000 is in contact with the mounting surface, and the rear is raised to accommodate the power supply, and the helmet 1000 with the sound device body 3 attached is placed on it for charging.

[0126] Here, as mentioned earlier, the helmet 1000 comes in various shapes and sizes, such as full-face and open-face types, and the power supply also comes in various thicknesses. In this case, when the helmet 1000 is placed for charging, the way it is lifted by the power supply at the rear of the helmet 1000 will vary. As a result, when the helmet 1000 is placed for charging, there is a possibility that the bottom surface of the sound device body 3 will be slightly tilted relative to the top surface of the power supply. If this tilt occurs, a gap will be created, and the charging efficiency will decrease.

[0127] As shown in Figures 19(A) and 19(B), in this embodiment, the charging bulge 49 bulges downward from the lower surface of the sound device body 3 and is shorter in the front-to-back direction than in the left-to-right direction. On the inner surface of the charging bulge, a flat power receiving coil 87 with a roughly rounded rectangular shape that is long in the left-to-right direction is provided so as to be completely covered by the inner surface of the charging bulge 49. When the sound device body 3 is placed on the upper surface of the power supply and there is an incline, the front or rear end of the charging bulge 49 will come into contact with it, and the other end will be raised by the incline, creating a gap. This gap will be larger if the width between the front and rear ends is large, but in this embodiment, the front-to-back width of the charging bulge 49 is configured to be short, so the resulting gap will be small. Therefore, even if there is an incline between the lower surface of the sound device body 3 and the upper surface of the power supply, the gap will be small and the impact on charging efficiency will be small.

[0128] In other words, the structure of the sound device body 3 of this embodiment can also be described as follows. A helmet acoustic device for use attached to a helmet having an upward-facing recess, which is a storage recess, on the inside of the bottom rear of the helmet, wherein the helmet acoustic device comprises an acoustic device body that generates a drive signal, and an acoustic generator connected to the acoustic device body by a connecting cable that generates sound inside the helmet in response to the drive signal, wherein the acoustic device body is configured to be attached with at least a part of it stored in the storage recess, the acoustic device body has a power receiving coil from which power for charging is wirelessly supplied to a battery inside the acoustic device body, the power receiving coil is formed facing downward, has a width in the front-to-back direction shorter than its width, is housed in a housing that covers the power receiving coil and has a width in the front-to-back direction shorter than its width, and is configured to protrude downward from the storage recess. Furthermore, by configuring the helmet-mounted acoustic device in this way, it became possible to minimize the gap between the bottom surface of the acoustic device body and the top surface of the power supply, even if there is a slope, thus minimizing the impact on charging efficiency.

[0129] Although this embodiment describes a helmet sound device 1 using an exciter 7 in the sound unit 5, it can of course also be applied to helmet sound devices that use speakers. This is because it can be used just as conveniently with helmet sound devices or helmet intercom devices that use speakers located near the ears inside the helmet.

[0130] Furthermore, for example, two recesses may be provided on the center of the front-to-back width of the power receiving coil 87, near the left and right ends of the charging bulge 49, and two protrusions corresponding to these recesses may be provided on the left and right sides of the upper surface of the power supply unit, on the center of the front-to-back width of the power supply coil. If the fitting of the recesses and protrusions is configured to be loose, the lower surface of the sound device body 3 and the upper surface of the power supply unit can be tilted, and the positioning of the power receiving coil 87 and the power supply coil can also be adjusted. The same applies when the recesses and protrusions are reversed. In any case, this effect can be obtained by configuring the power receiving coil 87 and the power supply coil to fit together so that they can swing in the front-to-back direction with respect to each other approximately at their center.

[0131] Furthermore, for example, the height of the mounting legs of the power supply can be adjusted to adjust the angle between the top surface of the power supply and the mounting surface, the bottom case 47 can be rotated in the front-to-back direction relative to the storage case 48, or a power supply specifically for that helmet can be provided. In this case, since no tilt occurs between the bottom surface of the sound device body 3 and the top surface of the power supply, the entire surface of the charging bulge 49 can be brought into close contact with the top surface of the power supply. When configured in this way, even if the charging bulge 49 does not bulge out from the bottom surface of the sound device body 3 but is on the same plane, charging can be performed without a decrease in charging efficiency.

[0132] Furthermore, the main unit 3 of this embodiment of the audio device is also provided with a connection connector 35 in addition to the power receiving coil 87. This connection connector 35 enables firmware updates and other functions, as well as so-called top-up charging. In other words, it becomes possible to charge the device using a mobile battery or the like while touring on a motorcycle, for example, during lunchtime.

[0133] Alternatively, the connection connector 35 could be removed from the main unit of the sound device 3, and charging could be performed solely by the power receiving coil 87. Removing the connection connector 35 would allow for cost reduction and miniaturization, and as mentioned above, firmware updates and other such updates can be performed by communication between the main unit of the sound device 3 and the mobile terminal S.

[0134] (Fifth embodiment) A fifth embodiment of the present invention will be described with reference to Figures 20(A) and 20(B). In this fifth embodiment, the same helmet sound device 1 as in the first embodiment is used, but because the configuration of the helmet 1000 to which it is attached is different, the sound device body 3 of the corresponding sound device body unit 2 is used. Furthermore, it is configured to make charging easier.Hereafter, the same parts as in the first to fourth embodiments are denoted by the same reference numerals and their descriptions are omitted, and only the different parts are described.

[0135] As explained in the fourth embodiment, charging the sound device body 3 while it is attached to the helmet 1000 simplifies handling and makes it convenient. Therefore, this embodiment shows the sound device body 3 corresponding to helmets 1000 with different configurations, and also shows a configuration that enables easy and stable charging of the helmet sound device 1 while it is attached to the helmet 1000.

[0136] Figures 20(A) and 20(B) show examples of use of the helmet sound device 1 of this embodiment. Figure 20(A) shows a part of a perspective view from the lower rear with the sound device body 3 of the sound device main unit 2 attached to the helmet 1000, and Figure 20(B) shows a part of a rear view. Here, the sound device main unit 2, as in the second embodiment, does not have a mounting adapter 4 and consists only of the sound device main unit 3. Also, the connection cable 21 and the like are omitted from the description.

[0137] As shown in Figures 20(A) and 20(B), the helmet 1000 of this embodiment has a storage recess 1400, similar to that shown in the second embodiment, but its configuration is different. In the helmet 1000 of the second embodiment, the lower edge of the rear part is slightly bulged outwards towards the back, and a recess extending upward from the bottom is provided on the inner surface of this bulge to form the storage recess 1400. In contrast, the helmet 1000 of this embodiment has a substantially rectangular storage recess 1400 of a predetermined thickness on the back side. Therefore, it is possible to store the storage case 48 of the acoustic device body 3, which has a substantially rectangular plate shape, in the storage recess 1400. The helmet 1000 in this embodiment is either a full-face or open-face type.

[0138] Incidentally, safety performance standards for helmets used for riding motorcycles and similar vehicles are stipulated by JIS T8133. According to this standard, the impact absorption performance of the helmet from the upper front to the upper rear is required, and impact testing is mandatory. In the helmet 1000 of this embodiment, a storage recess 1400 is provided by thinning a portion of the rear side of the impact-absorbing liner 1300 in the lower rear area outside the range where impact testing is performed, within a range where safety can be ensured. That is, the storage recess 1400 is located in the gap between the inner surface of the shell 1100 and the impact-absorbing liner 1300. Therefore, the portions near the left and right ends of the rear side of the storage case 48 for the acoustic device body 3 are made slightly thinner, following the curved surface of the inner surface of the shell 1100. Of course, it is also possible to make the entire back side of the helmet 1000 bulge outwards to the back and provide a storage recess 1400, while still using an impact-absorbing liner 1300 that is sufficiently thick.

[0139] As shown in Figures 20(A) and (B), the acoustic device body 3 of this embodiment has an acoustic device body case 31 with a watertight structure composed of a bottom case 47 and a storage case 48. Specifically, the acoustic device body case 31 is composed of a bottom case 47, which is a bottom surface of a predetermined thickness with a roughly bow-shaped arc surface that bulges downward in the center in the left-right direction, and a roughly rectangular plate-shaped storage case 48 that protrudes upward from the bottom case 47. The roughly bow-shaped arc surface forms a connection operation section 32, on which a communication indicator 36, a power button 34, a charging indicator 37, and an external volume microphone hole 33 are arranged from right to left. In addition, mounting legs 40, 40 are formed on the left and right sides near the lower end of the connection operation section 32, and a connection connector 35 is provided in the approximate center of the rear side of the bottom case 47.

[0140] As shown in Figures 20(A) and 20(B), the bottom case 47 of the acoustic device body 3 is configured to bulge further downward from the lower edge of the helmet 1000 when viewed from the rear. Therefore, the connection connector 35 provided on the rear side of the bottom case 47 allows the connection plug P of the external cable to be inserted and connected from the rear side of the helmet 1000.

[0141] Incidentally, in the first to fourth embodiments, the connection connector 35 was located on the bottom surface of the sound device body 3 and was positioned facing downwards. In that case, when connecting the connection plug P of an external cable to the connection connector 35 while the sound device body 3 is still attached to the helmet 1000, it is necessary to do so with the helmet 1000 upside down. However, performing charging, which requires a predetermined amount of time, in this state presented a problem.

[0142] The outer surface of the helmet 1000 is roughly spherical, and when it is inverted, it is in a very unstable state. If you let go of it in this state to charge it for a set amount of time, it will roll away. If it rolls off a table or other surface and falls onto the floor, the helmet 1000 will be subjected to impact, and its shock absorption capabilities will be reduced.

[0143] Furthermore, although the Helmet 1000 for motorcycles is expensive, the paint on its exterior can be scratched or peeled off due to impacts such as drops. Even when the Helmet 1000 is placed on its side, it becomes just as unstable as when it is upside down. For example, if you prepare something like a donut-shaped cushion, you can place it upside down, but it won't be stable, and it will easily roll over with even a slight bump.

[0144] It is indeed most stable to place the helmet 1000 without changing its orientation. However, in the first to fourth embodiments, the connection connector 35 is located at the bottom of the helmet 1000 and is positioned facing downwards. Therefore, when the connection plug P is inserted, the connection plug P protrudes downwards from the bottom of the helmet 1000. In this state, if the helmet 1000 is placed with its bottom facing down, the weight of the helmet 1000 will act on the connection plug P. This can cause the external cable connected to the connection plug P to break, and if any force is applied to the helmet 1000, there is a possibility that the connection connector 35 of the sound device body 3 may break.

[0145] One of the objectives of this embodiment is to prevent external forces from being applied to the inserted connecting plug P, even when the bottom of the helmet 1000 is placed face down. In this embodiment, as shown in Figures 20(A) and 20(B), the connection connector 35 is located further below the lower edge of the helmet 1000 and is provided on the rear side of the bottom case 47, facing the rear side. When the connection plug P is inserted into the connection connector 35, the connection plug P is positioned away from both the lower edge of the helmet 1000's shell 1100 and the surface on which it is placed. With the above configuration, it is possible to prevent external forces from being applied to the connection plug P when the helmet 1000 is mounted.

[0146] In this embodiment, the connection plug P is inserted into the connection connector 35 from the rear side, but this is not the only configuration. For example, the connection connector 35 may be configured to face forward, so that when the connection plug P is inserted, the connection plug P is positioned away from both the lower edge of the impact-absorbing liner 1300 of the helmet 1000 and the mounting surface. Even with this configuration, it is possible to ensure that no external force is applied to the connection plug P when the helmet 1000 is placed with its bottom facing downwards. The same applies if the connection connector 35 is positioned to the left, right, or diagonally.

[0147] In other words, the connection connector 35 should be positioned not downward in the direction of the mounting surface, but approximately sideways (approximately parallel) to the mounting surface, so that the connection plug P is positioned away from both the lower edge of the helmet 1000 and the mounting surface. With this configuration, the helmet 1000 can be placed stably without any external force being applied to the connection plug P while it is inserted into the connection connector 35, and without changing the orientation of the helmet. Furthermore, since the bottom surface of the connection connector 35 has mounting legs 40, 40, the helmet 1000 can be mounted in a more stable position.

[0148] Here, the structure of the sound device body 3 in this embodiment can also be described as follows. A helmet sound device for use attached to a helmet having an upward-facing recess, which is a storage recess, on the inside of the bottom rear of the helmet, wherein the helmet sound device comprises a sound device body that generates a drive signal, and a sound generator connected to the sound device body by a connecting cable and generating sound inside the helmet in response to the drive signal, wherein at least a part of the sound device body is stored in the storage recess, and a connecting connector that supplies power for charging the battery inside the sound device body protrudes from the lower edge of the helmet and is oriented substantially to the side. By positioning the connection connector in this way, it is now possible to charge the helmet while it is in a stable position, without changing the orientation of the helmet, even with the connection plug inserted.

[0149] And we can also add the following: A helmet acoustic device characterized in that, when the helmet is placed on the helmet with the power supply cable plug inserted into the connector, the connector is held so that it does not come into contact with the lower edge of the helmet or the surface on which the helmet is placed. This configuration prevents stress from being applied to the connection plug while the helmet is in place, thus preventing the possibility of the power supply cable breaking or the connection connector being damaged.

[0150] Regarding the "sound generator that generates sound inside the helmet in response to a drive signal" mentioned above, in this embodiment a vibration-type sound generator is used as the sound generator, but it is not limited to this, and of course a speaker may be used as the sound generator. This is because a helmet sound device that uses a speaker located near the ears inside the helmet as the sound generator can produce the same effect. In other words, it becomes possible to stably place the helmet with the power supply cable plugged in.

[0151] In this embodiment, the mounting legs 40, 40 are provided on the left and right sides near the center of the lower end of the bottom surface of the sound device body 3, but they may also be provided near the left and right ends of the bottom surface and configured to protrude so that the helmet can be mounted. If the spacing between the mounting legs 40, 40 is increased, the helmet 1000 can be mounted in a more stable state.

[0152] Furthermore, in this embodiment, the bottom case 47 of the sound device body 3 is made to bulge downwards, but it is also possible to configure it so that only the connection connector 35 and the mounting legs 40, 40 bulge downwards, rather than the entire bottom case 47. This is because if the connection connector 35 protrudes from the lower edge of the helmet 1000 and is oriented laterally, the helmet 1000 can be charged and operated in a stable position. In this case, the bottom case 47 may be removed, and the connection connector 35 and mounting legs 40, 40 may be configured to bulge downwards directly from the storage case 48. In this case, for example, the width of the lower part of the connection connector 35 may be widened so that the connection connector 35 and the mounting legs 40, 40 are integrated into one unit.

[0153] Furthermore, the lower edge of the helmet 1000, such as the shell 1100 or the lower edge of the impact-absorbing liner 1300, may be slightly shaved upwards to create an arc-shaped recess in the area corresponding to the connection connector 35. This upward recess raises the position of the lower edge of the helmet 1000 at the location corresponding to the connection connector 35, thereby raising the position of the connection connector 35 while separating this lower edge from the connection plug P. This reduces the amount of downward protrusion of the connection connector 35 relative to the helmet 1000.

[0154] Furthermore, in the first to fourth embodiments, the connection connector 35 may be configured to protrude from the lower edge of the helmet 1000, similar to this embodiment, and the connection connector 35 may be oriented laterally. When the helmet is placed with the power supply cable's connection plug inserted into the connection connector, the connection plug may be held so as not to come into contact with either the lower edge of the helmet or the surface on which the helmet is placed. By adopting this configuration of the embodiment, it is possible to prevent force from being applied to the connection plug, thereby preventing the possibility of the power supply cable breaking or the connection connector being damaged, and enabling charging in a stable position with the bottom of the helmet 1000 facing downwards.

[0155] The helmet acoustic device of the present invention is not limited to the embodiments described above and shown in the drawings, and various modifications can be made without departing from the spirit of the invention. For example, the sound units 5, 5 and the microphone unit 6 are connected to the main sound device unit 2 via connecting cables 21, 21, 21 through waterproof connectors 22, 22, 22, respectively, but the configuration is not limited to this.

[0156] In other words, the connection cables 21, 21, 21 may be combined into a single connector and connected to the main unit 2 of the sound device. Alternatively, a connector or contacts may be provided in the back of the storage recess 1400, so that connection and contact are established simply by inserting the main unit 2 of the sound device into the storage recess 1400. By configuring it in this way, the main unit 2 of the sound device can be removed from the helmet 1000 and charged independently, making it even easier.

[0157] Furthermore, while it was explained that user U makes calls via mobile terminal S, this is not the only option. For example, in the intercom device described in Non-Patent Document 1, intercom conversations are possible between identical intercom devices. The sound device main unit 2 could be configured similarly to provide an intercom conversation function. With this configuration, direct communication between helmet sound devices 1 would be possible without using mobile terminal S.

[0158] In other words, while the above description refers to devices that can be attached to a helmet as helmet sound devices, it is of course possible to replace the term with, for example, helmet intercom devices. Here, the helmet sound device of the present invention refers to a device that allows sound to be heard while wearing a motorcycle helmet, and includes helmet intercom devices and the like.

[0159] Furthermore, the motorcycle helmet of the present invention is not limited to the helmet described in the above-mentioned embodiment. For example, a standard called "Universal Communication Solution" has been proposed, which involves providing an upward-facing recess at the bottom rear of the helmet to store a motorcycle intercom. It is certainly possible to configure the system to conform to this standard.

[0160] In other words, it is certainly possible to shape the external form of the sound device body 3 of the sound device body unit 2 to fit this storage recess, and to attach the sound units 5, 5 as shown in the first embodiment to the helmet. Here, as mentioned above, the main body of the sound device 3 may be configured to have a bottom surface of a predetermined thickness that covers and seals the opening of the storage recess, and a storage section that bulges upward from the top surface of the bottom surface and is housed in the storage recess.

[0161] By configuring the sound device body 3 in this way, the bottom surface is wider than the lower end surface of the storage section, the storage section houses at least a battery for driving the helmet sound device, and the bottom surface of the storage section can be provided with an operating section, a display section, and a connection connector, resulting in a larger operating surface that is easier for the user U to operate.

[0162] Furthermore, by configuring the bottom surface to be wider than the lower end surface of the storage compartment, it becomes possible to install a power receiving coil on the bottom surface, enabling wireless charging using a power supply such as a charging pad. In addition, charging becomes possible simply by placing the helmet on the charger without changing its orientation, allowing for stable charging of the helmet.

[0163] Furthermore, the sound device itself may have a power supply connector, and the connector may be configured to protrude from the lower edge of the helmet and be oriented approximately laterally with respect to the mounting surface on which the helmet is placed. With the power plug inserted, it becomes possible to charge the helmet while it is placed stably without changing its orientation.

[0164] Alternatively, the receiving coil may be configured to protrude downward from the lower end surface of the storage compartment, with a front-to-back width shorter than the width of the receiving coil, and housed within the housing of the sound device body 3, which has a front-to-back width shorter than its width. In this way, even if there is a slope between the bottom surface of the sound device body and the top surface of the power supply, the gap will be small, and the impact on charging efficiency will be small. When various shapes and sizes of helmets conforming to this standard are produced, this configuration will be effectively utilized when wirelessly powering sound devices for these helmets.

[0165] Furthermore, it is certainly possible to configure the helmets to conform to this standard by applying the detailed features described in the first to fifth embodiments mentioned above. This is because it would make them even more convenient to use.

[0166] Furthermore, although the above-described embodiment explained the helmet sound device as being for motorcycles, it is not limited to this, and of course it can also be used for, for example, four-wheeled automobile races or boat races.

[0167] For example, by attaching the helmet sound device of the present invention to a helmet molded from foam or the like, spatial audio using technologies such as Dolby Atmos® can be reproduced, resulting in a sound device with excellent three-dimensional localization. This can be used for watching movies or listening to music with noise cancellation enabled, and is also convenient for gaming. In other words, it becomes possible to gain an advantage in the game by understanding the situation through sound, such as the footsteps of opponents or the positions of teammates, while communicating with distant players using a microphone. [Explanation of symbols]

[0168] U user S Mobile device P connection plug 1. Helmet sound device 2. Main unit of the sound device 21 Connection Cables 22 Waterproof Connectors 3. Main unit of the sound device 31. Audio device main unit case 32 Connection Operation Section 33 External volume microphone hole 34 Power button 35 connection connectors 36 Communication display 37 Charging display 38 Engaging part 39 Engagement protrusion 4. Mounting adapter 41 Engaged portion 42 Engaged convex part 43 Engagement Lock 44 Cable cutouts 45 Helmet mounting surface 46. ​​Double-sided adhesive tape for mounting adapters 47 Bottom case 48 Storage compartment case 49 Power receiving bulge 40 Mounting legs 5. Acoustic Unit 51 External part 52 Inner surface 53 connection cable holes 54 external microphone holes 55 Waterproof Cable Bushings 56 Waterproof packing sheet 57 Skirt section 58 Double-sided adhesive tape for sound units 59 Exciter mounting recess 6 Microphone Units 61. Microphone unit with arm 62 Voice microphone arm 7 Exciter 71 Exciter Frame 72 Vibration transmission section 73 Damper 74 Double-sided adhesive tape for exciters 75 coils 76 Terminal board 77 York 78 Permanent Magnets 81 External volume microphone 82. External microphone 83 Waterproof sheet 84 Windshield foam material 85 Voice Microphone 86 Battery 87 Power receiving coil 9 Main board 91 Control Unit 92 Power supply section 93 Display section 94 Operation section 95 Exciter drive unit 96 External sound microphone signal processing unit 97 Audio microphone signal processing unit 98 External volume microphone signal processing unit 99 Communications Department 1000 helmets 1100 shells 1200 Shield 1300 Shock-absorbing liner 1400 Storage recess 1500 Mounting part 1600 Mounting edge 2000 Dummy Ear Microphone 2100 Ear Dummy 2200 Dummy Microphone

Claims

1. A helmet sound device that is attached to and used with a motorcycle helmet, The aforementioned helmet acoustic device has two vibration-type acoustic units, each comprising an acoustic device body that generates a drive signal, and a vibration-type acoustic generator connected to the acoustic device body by a connecting cable that vibrates the helmet, and a housing that houses the vibration-type acoustic generator. The two vibration-type acoustic units are fixed to the left and right sides of the outer surface of the helmet, and each of the vibration-type acoustic generators generates vibrations in response to the drive signal, causing the helmet to vibrate and thereby generating sound. The sound device body is configured to communicate with a mobile terminal, and the sound device body generates the drive signal in response to the music sound signal from the mobile terminal, which drives the vibration-type sound unit to play music inside the helmet. The vibration-type acoustic unit is configured such that an external microphone is housed within the housing near the vibration-type acoustic generator. The external microphone detects external noise, and the acoustic device itself processes the signal to invert the phase of the external noise, creating an acoustic signal. If music is being played, this signal is combined with the music's acoustic signal to generate the drive signal, which drives the vibration-type acoustic unit, thereby performing noise cancellation inside the helmet. A helmet-mounted acoustic device characterized by the following features.

2. The two vibration-type acoustic units are each fixed to the lower edge of the outer surface of the left and right sides of the helmet. The acoustic device for a helmet according to claim 1, characterized in that it is a helmet.

3. The vibration-type sound generator and the external sound microphone are housed within their respective casings, positioned approximately front to back with respect to the direction of travel of the motorcycle. The helmet sound device according to claim 2, characterized in that it is a helmet sound device.

4. The rated input of the aforementioned vibration-type sound generator is 1 watt or less and 0.3 watts or more. The acoustic device for helmets according to claim 3, characterized in that it is a helmet acoustic device.

5. The aforementioned helmet sound device has a sound microphone connected to the sound device body by a connecting cable, Using the aforementioned voice microphone and vibration-type acoustic unit, the user is configured to be able to make calls via the aforementioned mobile terminal or the aforementioned acoustic device itself, which is configured to communicate with the acoustic device itself. The acoustic device for a helmet according to any one of claims 1 to 4.

6. At least a portion of the housing of the sound device body is configured to be housed in a storage recess which is an upward-facing recess in the inner bottom of the rear of the helmet, and to be attachable. The acoustic device for a helmet according to any one of claims 1 to 4.

7. The vibration-type acoustic unit is configured to be attachable to a substantially triangular mounting portion provided on the lower edge of the outer surface of the left and right sides of the helmet, and has a substantially triangular shape that fits the mounting portion. The helmet sound device according to claim 6.

8. The housing of the sound device body has a bottom portion of a predetermined thickness that covers and seals the opening of the storage recess, with an area larger than the opening, and a storage portion that bulges upward from the top surface of the bottom portion and is housed in the storage recess, and a power receiving coil for wireless charging is provided in the bottom portion. The helmet sound device according to claim 6.

9. The sound device body is configured to be installed in the storage recess, with at least a portion of it being housed within it. It has a connection connector that supplies power for charging to the battery inside the sound device body. The connection connector protrudes from the lower edge of the helmet, and is configured to face approximately horizontally with respect to the mounting surface when the bottom of the helmet is placed face down. The helmet sound device according to claim 6.

10. The helmet acoustic device is configured to interrupt noise cancellation or interrupt the phase inversion of the approximate frequency range of the emergency sound if the external noise detected by the external sound microphone is above a predetermined volume. The acoustic device for a helmet according to any one of claims 1 to 4.

11. The helmet sound device is configured such that, if the external noise detected by the external sound microphone is above a predetermined volume level, it will either lower the volume of the music playback or interrupt the playback if music is being played. The acoustic device for a helmet according to any one of claims 1 to 4.

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