Electroacoustic transducer and helmet

Abstract

[Problem] To enable a reduction in volume when an impact is applied. [Solution] An electroacoustic transducer 1 for transmitting vibrations to a human body, comprising: a movable portion 10 that vibrates according to an input signal; a fixed portion 20 comprising a coil 21 into which at least a part of the movable portion is inserted; elastic members 30 disposed as a pair at opposite ends of the movable portion in the vibration direction; and a casing 40 connected to the fixed portion so as to cover the movable portion.

Description

Electroacoustic transducer and helmet

[0001] The present invention relates to an electroacoustic transducer that transmits vibration to the human body.

[0002] There is known an electroacoustic transducer that can hear vibrations transmitted through bone conduction generated from the skull or the like as sound by bringing the outer wall surface into contact with the skull or the bone around the entrance of the external auditory canal.

[0003] Conventionally, for example, there is known a bone conduction vibration source device for a mobile phone or the like, which acoustically processes an audio signal for bone conduction vibration and outputs the processed signal as a drive signal to a bone conduction vibration source (see, for example, Patent Document 1). In addition, a stereo earphone having a bone conduction part and a branch part having one end connected to the bone conduction part and serving as a vibration source is disclosed (see, for example, Patent Document 2).

[0004] When an electroacoustic transducer is housed inside a helmet or the like, if the electroacoustic transducer is damaged when an impact is applied to the helmet or the like, the electroacoustic transducer may hit the head of the wearer wearing the helmet or the like, and the wearer may be injured. Therefore, in order to protect the head from an impact, an electroacoustic transducer that becomes as small as possible in volume when an impact is applied is required.

[0005] Japanese Patent Application Laid-Open No. 2013-197730 Japanese Patent Application Laid-Open No. 2014-116755

[0006] An object of the present invention is to provide an electroacoustic transducer that can reduce its volume when an impact is applied.

[0007] The electroacoustic transducer according to the present invention is an electroacoustic transducer that transmits vibration to the human body, and includes a movable part that vibrates in response to an input signal, a fixed part that includes a coil through which at least a part of the movable part is inserted, elastic members disposed in pairs at both ends in the vibration direction of the movable part, and a casing formed by vacuum molding and connected to the fixed part so as to cover the movable part.

[0008] According to the present invention, it is possible to provide an electroacoustic transducer that can reduce its volume when an impact is applied.

[0009] [Correction based on Rule 91 03.10.2025] A figure showing a helmet according to the first embodiment of the present invention, (a) a schematic right side view of the helmet, (b) a schematic right side view showing a part of the helmet transparently in a worn state, and (c) a schematic left side view showing a part of the helmet transparently in a worn state. A schematic perspective view showing a cross-sectional view of some members of an electroacoustic transducer according to the first embodiment of the present invention. A schematic longitudinal cross-sectional view showing an example of the electroacoustic transducer under vertical force. A schematic perspective view showing a cross-sectional view of some members of an electroacoustic transducer according to the second embodiment of the present invention.

[0010] Hereinafter, embodiments of the electroacoustic transducer according to the present invention will be described with reference to the drawings. In the following description, the axial direction of the electroacoustic transducer 1 will be referred to as the Y direction, and the directions perpendicular to the Y direction will be referred to as the X direction and the Z direction. The surface facing the +Y direction will be referred to as the top surface, and the surface facing the -Y direction will be referred to as the bottom surface. Furthermore, the surface facing the -X direction will be referred to as the front, and the surface facing the +X direction will be referred to as the back. In this embodiment, the present invention includes headphones and an electroacoustic transducer that transmit vibrations to any bone, including ear cartilage, cartilage other than ear cartilage, and hard bone such as the skull.

[0011] ●Helmet As shown in Figure 1(a), the helmet 200 is a protective device worn on the head of a human body to protect the head, and comprises a housing 201 that forms the outer shape of the helmet 200, and an electroacoustic transducer 1 held on the inside of the side of the housing 201. At least one electroacoustic transducer 1 is held on the inside of either the left or right side of the housing 201, at a position corresponding to the left ear or the right ear. In the example shown in Figures 1(b) and 1(c), which show the inside of the helmet 200 transparently within the dashed lines, the electroacoustic transducers 1 are paired left and right and are positioned to correspond to the left and right ears of the wearer when worn. Here, the electroacoustic transducer 1 only needs to be positioned in a position that contacts the bone of the wearer when the helmet 200 is worn, and may be in a position that overlaps with the ear in a side view, or, as shown in Figures 1(b) and 1(c), it may be in a position close to the ear, for example, in front of and below the ear, close to the jaw.

[0012] ●Electroacoustic Converter (1)● A first embodiment of the electroacoustic converter of this embodiment will be described. The electroacoustic converter 1 is, for example, a speaker unit. The electroacoustic converter 1 is held on the inside of the side of a housing 201 (see Figures 1(b) and 1(c)) that constitutes the outer shape of an article worn on the head, such as a helmet 200 (see Figure 1(a)), and is positioned to correspond to either the left or right ear. Alternatively, the electroacoustic converter 1 may be held on the inside of both sides of the housing 201 and positioned in pairs to correspond to the left and right ears, respectively. The electroacoustic converter 1 generates vibrations in response to electrical signals input by appropriate communication processing, and these vibrations vibrate the wearer's body as well as the helmet 200 itself. As a result, the vibrations corresponding to the electrical signals are indirectly transmitted to the wearer's body via the helmet 200. With a configuration that transmits vibrations to the human body, such as the electroacoustic converter 1 of the present invention, even if the wearer is wearing earplugs to block out external noise, the necessary sound can be appropriately delivered to the wearer by vibration. In other words, the electroacoustic converter 1 according to the present invention is useful even in environments where noise would have adverse effects on the ears if earplugs were not worn.

[0013] As shown in Figure 2, the electroacoustic transducer 1 is, for example, a member with a roughly frustoconical shape. The electroacoustic transducer 1 mainly comprises a movable part 10, a fixed part 20, an elastic member 30, and a casing 40.

[0014] The movable part 10 is a component that vibrates vertically in the figure in response to an input signal.

[0015] The movable part 10 mainly comprises a magnet 12 and a center yoke 13.

[0016] The magnet 12 is a roughly cylindrical magnet. The center yoke 13 is a disc-shaped member that is at one end of the movable part 10 in the direction of vibration and is connected to the lower end of the magnet 12 in the figure. In this embodiment, the center yoke 13 is connected to the unit base 22, which will be described later, via an elastic member 32.

[0017] The fixed part 20 mainly comprises a coil 21 and a unit base 22.

[0018] The coil 21 is an annular member, and the magnet 12 and the center yoke 13 are inserted through a hole 23 formed in the center of the coil 21. The outer diameters of the magnet 12 and the center yoke 13 are smaller than the inner diameter of the hole 23 in the coil 21. Therefore, the magnet 12 and the center yoke 13 are movable axially (y-direction) within the hole 23. A Lorentz force is generated between the magnet 12 and the coil 21. As a result, the movable part 10 vibrates axially. A cable (not shown) for inputting electrical signals is connected to the coil 21. This cable extends from between the unit base 22 and the casing 40 to the outside of the electroacoustic transducer 1.

[0019] The unit base 22 is a component that forms the bottom surface of the electroacoustic transducer 1 and holds the coil 21. The unit base 22 may be a flat plate-shaped member. A cylindrical rib 22a is formed on the unit base 22, and the coil 21 abuts against the inner circumference of the rib 22a. The coil 21 and the rib 22a are bonded to each other. The end of the casing 40 is connected to the outer circumference of the rib 22a. The rib 22a and the casing 40 are connected, for example, by heat welding or adhesive. The unit base 22 may have a shape in which a flat plate extends outward from the outside of the casing 40. For example, a terminal plate may be provided on the flat plate.

[0020] The elastic members 30 are arranged in pairs on either side of the movable part 10 in the direction of vibration. The elastic members 30 include a first elastic member 31 and a second elastic member 32. One end of the first elastic member 31 is connected to the first end of the movable part 10 in the direction of vibration, which in the example shown in the figure is the magnet 12. The other end of the first elastic member 31 is connected to the casing 40. As a result, the first elastic member 31 holds the movable part 10 between the movable part 10 and the casing 40.

[0021] One end of the second elastic member 32 is connected to the second end of the movable part 10 in the direction of vibration, which in the example shown in the figure is the center yoke 13. The other end of the second elastic member 32 is connected to the fixed part 20, specifically the unit base 22. As a result, the second elastic member 32 holds the movable part 10 relative to the unit base 22.

[0022] The elastic member 30 and each member are bonded together, for example, by so-called double-sided tape, but any bonding method can be adopted.

[0023] The elastic member 30 is a member that exhibits elastic force, for example, through a porous structure, and more specifically, it is a urethane foam. Alternatively, the elastic member 30 may be formed from a suitable sponge material. Furthermore, the elastic member 30 may be composed of an elastic body such as rubber or gel. Even further, the elastic member 30 may be composed of vinyl bubble wrap or a part thereof. Even further, the elastic member 30 may be a leaf spring made of a suitable material such as metal or resin. Note that by forming the elastic member 30 from a sponge material, it can be constructed at a lower cost, be smaller, and be lighter compared to the case where a leaf spring is used. The elastic members 31 and 32 may have similar or different configurations.

[0024] The casing 40 is connected to the fixed part 20 and is a component that covers the movable part 10. The casing 40, together with the unit base 22, is a component that constitutes the outer shape of the electroacoustic transducer 1, and is, for example, a frustoconical component. The outer shape of the casing 40 is, for example, about 13 mm in diameter.

[0025] The casing 40 is formed of a thermoplastic resin, for example, with a thickness of 0.6 mm or less. The thermoplastic resin is, for example, PET resin or PVC resin. Therefore, the casing 40 is constructed with a strength that allows it to be crushed by external impact. The casing 40 can be made to a thin and uniform thickness of 0.6 mm or less by, for example, vacuum forming. If the thickness of the casing 40 is made of, for example, 0.7 mm or more, the electroacoustic transducer 1 will not be crushed by external impact, and the electroacoustic transducer 1 may become a foreign object and cause injury to the wearer's head, so it is necessary to make it 0.6 mm or less in thickness.

[0026] Figure 3 is a schematic longitudinal cross-sectional view showing an example of the electroacoustic transducer 1 under vertical force. Note that the applied force is not limited to a force having only a vertical component, but may be any appropriate force including a vertical component. Also, the force may be a so-called impact force. Since the electroacoustic transducer 1 is most easily crushed in the vertical direction, when force is applied to the electroacoustic transducer 1, as shown in Figure 3, the space S formed between the casing 40 and the fixing part 20 is crushed together with the casing 40, and the external shape of the electroacoustic transducer 1 is reduced in the vertical direction. For example, while the height in the operating state is approximately 5.7 mm, the height in the crushed state becomes approximately 3.5 mm. Therefore, even if an impact is applied from the outside, fragments containing small parts or sharp shapes will not strike the wearer's head or face, thus preventing injury to the head and body. Also, as shown in the figure, the side walls of the casing 40 are soft and have so-called cushioning properties in the compression direction. Therefore, the temporal distribution of deformation that occurs before complete collapse is smoother compared to configurations with thicker side walls or those formed by injection molding. Since the impact applied to the helmet 200 from the outside is mainly in the compression direction, a configuration in which the casing 40 has a load against compression and generates resistance until complete failure can further reduce the impact on the wearer.

[0027] The casing 40 is connected to the fixing part 20 without any gaps. As a result, the space S formed by the casing 40 and the fixing part 20 is sealed. With this configuration, the inside of the electroacoustic transducer 1 is filled with air, so the strength of the electroacoustic transducer 1 is ensured under normal use conditions and it is less likely to be crushed except in the case of a strong impact such as a collision. In this case, for example, the cable extending from the coil 21 is welded to the casing 40 and the unit base 22. The casing 40 and the unit base 22 each have a flat plate-shaped protrusion (not shown) extending in the radial direction, and the cable may be sandwiched and welded by this protrusion. With this configuration, the space S can be sealed even when the cable from the fixing part 20 is led out to the outside of the electroacoustic transducer 1.

[0028] ●Electroacoustic Converter (2)● Here, we will describe a different embodiment of the electroacoustic converter of this embodiment, focusing on the parts that differ from the previously described form. Note that the same reference numerals are used for components that are the same as in the first embodiment. The electroacoustic converter 101 of the second embodiment shown in Figure 4 differs from the first embodiment in that it has appropriate protrusions 131a and 132a on the surfaces of the elastic members 131 and 132, and the movable part 110 is held at the protrusions 131a and 132a. The elastic members 131 and 132 are made of urethane foam and are formed from appropriate sponge material, rubber, or gel material. The protrusions 131a and 132a may be a single annular shape or multiple protrusions may be formed. The inside of the protrusions 131a and 132a may be filled with elastic members 131 and 132, or it may be hollow.

[0029] Columnar portions 131b and 132b are formed in the center of the elastic members 131 and 132, respectively, extending toward the movable part 110. In this embodiment, holes 112a and 113a are formed in the vibration direction centers of the magnet 112 and center yoke 113 of the movable part 110, and they are in communication with each other. The columnar portions 131b and 132b are inserted through these holes 112a and 113a. The columnar portions 131b and 132b may also be bonded to the inner circumferential surfaces of the holes 112a and 113a. Even with this configuration, the movable part 110 is held between the unit base 22 and the casing 40 by the elastic members 131 and 132.

[0030] As described above, the present invention provides an electroacoustic transducer that can reduce its volume when an impact is applied. The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of its gist.

[0031] 1 Electroacoustic transducer 10 Movable part 12 Magnet 13 Center yoke 20 Fixed part 21 Coil 22 Unit base 30 Elastic member 40 Casing

Claims

1. An electroacoustic transducer for transmitting vibrations to the human body, comprising: a movable part that vibrates in response to an input signal; a fixed part having a coil through which at least a portion of the movable part is inserted; elastic members arranged in pairs at both ends of the movable part in the direction of vibration; and a casing connected to the fixed part so as to cover the movable part.

2. The electroacoustic transducer according to claim 1, wherein the casing is formed by vacuum forming.

3. The electroacoustic transducer according to claim 1, wherein the casing has a thickness of 0.6 mm or less and is made of a thermoplastic resin.

4. The electroacoustic transducer according to claim 1, wherein the casing is a bottomed cylindrical shape, the open end of the casing is connected to the fixing part without any gaps, and the space formed by the casing and the fixing part is sealed.

5. The electroacoustic transducer according to claim 1, wherein the casing is a bottomed cylindrical shape, a space is formed between the casing and the fixed part when the movable part is housed, and when the casing is subjected to an impact, the casing and the space collapse, reducing the external shape of the electroacoustic transducer.

6. A helmet comprising: a housing that forms the outer shape of the helmet; and an electroacoustic transducer held on the inside of the side surface of the housing, wherein the electroacoustic transducer is the electroacoustic transducer described in any one of claims 1 to 5.

Images