Bone conduction speaker unit and headrest incorporating the same

Abstract

[Problem] To provide a bone conduction speaker unit and a headrest incorporating the same, said bone conduction speaker unit being capable of suppressing, as much as possible, the occurrence of undesirable phenomena, such as the necessary occurrence of sounds in a bone conduction speaker and sound leakage when the bone conduction speaker is incorporated by a headrest, moreover, said bone conduction speaker unit being suitable for the incorporation of such a headrest. [Solution] This bone conduction speaker unit comprises: a base frame 2; a low-repulsion ring 3 that is fixed to the upper surface of the base frame 2; a damping member 4 that is inserted into the base frame 2; a bone conduction speaker body 5 that is mounted on the damping member 4 in such a manner that the bone conduction speaker body 5 is surrounded by the low-repulsion ring 3; and a contact 6 that is mounted on the low-repulsion ring 3 such that the contact 6 covers the bone conduction speaker body 5. The contact 6 is configured to abut the vibration plane of the bone conduction speaker body 5 at a load and to depart from the vibration plane of the bone conduction speaker body 5 at no load.

Description

[Technical field]

[0001] The present invention relates to a bone conduction speaker unit and a headrest incorporating the same, and more specifically, to a bone conduction speaker unit suitable for incorporation into headrests for passenger seats in various forms of transportation including automobiles, and headrests for seating in theaters, cinemas, theme parks, etc., and a headrest incorporating the same. [Background technology]

[0002] Generally, bone conduction speakers are intended to transmit generated vibrations to the human body, and are widely used as an effective sound transmission device for people with hearing loss under certain conditions, such as in high noise environments. However, in the case of bone conduction speakers, the generated vibrations are also transmitted to the housing that holds the speaker, which can cause undesirable phenomena such as buzzing and sound leakage. Figure 7 shows this situation, with arrow a indicating the vibrations that are transmitted to the human body as audio signals, arrow b indicating the vibrations that are transmitted to the housing as a reaction force, arrow c indicating sound leakage caused by the contact vibrating the air, and arrow d indicating the buzzing caused by the housing resonating due to arrow b and the air vibrating.

[0003] Proposals have been made to incorporate this bone conduction speaker into the headrest of an automobile. For example, JP 2018-125829 A (Patent Document 1) discloses an acoustic device for a seat that incorporates a bone conduction speaker in a head support seat that is partially bulged so that the head is always in close contact with the back of the head when the person is seated, and Utility Model Registration No. 3219108 (Patent Document 2) discloses a headrest with a built-in bone conduction speaker, in which the front of the headrest exterior body on which the bone conduction speaker is arranged is made of an elastic material, and the head of the seat occupant can be wrapped in a state where it is reliably buried inside the headrest, thereby picking up less noise inside and outside the vehicle and allowing the sound from the bone conduction speaker to be clearly transmitted to the seat occupant.

[0004] However, in the case of the invention of Patent Document 1, the bone conduction speaker is merely built into the head support seat, and in the case of the invention of Patent Document 2, the bone conduction speaker is merely placed inside the headrest exterior body whose front surface is made of an elastic material, and there is no disclosure of a suitable configuration for a bone conduction speaker to be built into a headrest, nor is there any mention of how to place the bone conduction speaker. Furthermore, no consideration is given at all to preventing the occurrence of undesirable phenomena such as the above-mentioned ringing and sound leakage that are unique to bone conduction speakers. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-125829 A [Patent Document 2] Utility Model Registration No. 3219108 Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, in the case of the headrest with a built-in bone conduction speaker described in the above patent documents, it is merely stated that the bone conduction speaker is placed inside the headrest, and there is no description as to what configuration the bone conduction speaker should have and how it should be placed, nor is there any disclosure of means for preventing undesirable phenomena such as ringing and sound leakage that inevitably occur with bone conduction speakers.

[0007] Therefore, an object of the present invention is to provide a bone conduction speaker unit suitable for incorporation into a headrest, which can minimize the occurrence of undesirable phenomena such as noise and sound leakage that inevitably occur with bone conduction speakers when they are incorporated into a headrest, and a headrest incorporating the same. [Means for solving the problem]

[0008] The invention according to claim 1 for solving the above problem comprises a base frame, a low-resilience ring-shaped body fixed to an upper surface of the base frame, a vibration-damping material fitted into the base frame, a bone-conduction speaker body placed on the vibration-damping material while being surrounded by the low-resilience ring-shaped body, and a contact placed on the low-resilience ring-shaped body so as to cover the bone-conduction speaker body, The contact comprises a pair of legs fixed on the low-resilience annular body and a bridge extending between the legs so as to bulge outward, The bone conduction speaker unit is characterized in that the contact abuts against the vibration surface on the upper surface of the bone conduction speaker body when a load is applied, and is separated from the vibration surface of the bone conduction speaker body when no load is applied.

[0009] In one embodiment, the contact abuts against the vibration surface on the upper surface of the bone conduction speaker main body by pushing the low-resilience ring body when a load is applied, and moves away from the vibration surface of the bone conduction speaker main body as the low-resilience ring body elastically restores its shape when no load is applied.

[0010] In one embodiment, the contact is elastic and bends when loaded and pushes the low-resilience ring body to abut against the vibration surface on the upper surface of the bone conduction speaker main body, and when unloaded, the contact returns to its original shape and the low-resilience ring body returns to its original shape, moving away from the vibration surface of the bone conduction speaker main body.

[0011] In one embodiment, the contact has a convex portion that abuts against the vibration surface on the upper surface of the bone conduction speaker body when a load is applied and that is separated from the vibration surface of the bone conduction speaker body when no load is applied.

[0012] In one embodiment is before The bridge is cross-shaped in plan view and is hollowed out as much as possible.

[0013] Claims to solve the above problem 6 The invention relates to claims 1 to 5 A headrest incorporating the bone conduction speaker unit according to any one of claims 1 to 5, This headrest has a built-in bone conduction speaker unit, characterized in that an opening is formed in the surface of the headrest that contacts the rear of the head, a ventilation cover is placed over the opening, and the bone conduction speaker unit is positioned inside the opening so that the contact is always in contact with the ventilation cover. Effect of the Invention

[0014] The bone conduction speaker unit of the present invention is as described above. Since the bone conduction speaker body is mounted on a vibration-damping material which is a weight, vibrations in the direction opposite to the vibration surface are reduced, and the surface area of ​​the contacts which come into contact with the human body is formed to be as small as possible, which has the effect of suppressing noise.

[0015] In addition to the above effects, in the headrest incorporating the bone conduction speaker unit according to the present invention, only the contact portion with the contact of the incorporated bone conduction speaker unit is made of a breathable cover made of a breathable material, so that the transmission of vibration to the epidermis is suppressed, thereby reducing noise caused by vibration of the epidermis and enabling the release of heat. [Brief description of the drawings]

[0016] [Figure 1] 1 is a perspective view of an embodiment of a bone conduction speaker unit according to the present invention; [Diagram 2] 1 is a plan view of an embodiment of a bone conduction speaker unit according to the present invention. [Diagram 3] 1 is a longitudinal sectional view of an embodiment of a bone conduction speaker unit according to the present invention. [Figure 4] 1A to 1C are diagrams illustrating the operation of the bone conduction speaker unit according to the present invention. [Diagram 5] 1 is a perspective view showing an example of the configuration of a headrest incorporating a bone conduction speaker unit according to the present invention; [Figure 6] 1 is a simplified vertical cross-sectional view showing an example of the configuration of a headrest incorporating a bone conduction speaker unit according to the present invention. [Figure 7]1A and 1B are diagrams for explaining problems with a conventional bone conduction speaker unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The embodiment of the present invention will be described in detail with reference to the accompanying drawings. As shown in Figs. 1 to 3, the bone conduction speaker unit 1 according to the present invention comprises an annular base frame 2, a low-resilience ring-shaped body 3 fixed to the upper surface of the base frame 2, a vibration-damping material 4 fitted and supported within the base frame 2, a bone conduction speaker body 5 arranged on the vibration-damping material 4 while being surrounded by the low-resilience ring-shaped body 3, and a contact 6 arranged on the low-resilience ring-shaped body 3 so as to cover the vibration surface on the upper surface of the bone conduction speaker body 5. For example, a low-resilience urethane sponge can be used as the low-resilience ring-shaped body 3.

[0018] The bone conduction speaker main body 5 itself has a general structure, and detailed description thereof will be omitted. The upper surface of the illustrated bone conduction speaker main body 5 serves as the vibrating surface (diaphragm). The illustrated example of the base frame 2 has four legs for holding the vibration-damping material 4. Typically, the base frame 2 is made of a hard resin, and the vibration-damping material 4 is made of a metal material such as brass having vibration-damping properties.

[0019] The contact 6 comes into contact with the vibration surface of the bone conduction speaker body 5 when pressed, and moves away from the vibration surface of the bone conduction speaker body 5 when the pressing force is released. In order to ensure the contact and separation from the vibration surface of the bone conduction speaker body 5, it is preferable to provide a convex portion 7 on the inner top surface of the contact 6 (FIGS. 3 and 4). For example, the contact 6 is composed of a pair of legs 8 fixed on the low-resilience ring-shaped body 3 and a bridge 9 that bulges outward and spans between the legs 8 (FIGS. 1 and 2), and the convex portion 7 is provided on the back surface of the center of the bridge. The bridge 9 in the illustrated example is cross-shaped in a plan view, and is hollowed out as much as possible (hollowed out portion 10). The reason for providing the hollowed out portion 10 as much as possible in this way is to reduce the surface area in the vibration direction, reduce air vibration, and reduce sound leakage (reducing vibration in the direction of the arrow c in FIG. 7).

[0020] Typically, the contact 6 is made of a rigid material such as hard resin, and when the low-resilience ring-shaped body 3 is pressed down under load, the convex portion 7 comes into contact with the vibration surface on the top surface of the bone conduction speaker main body 5 (see Figures 4(B) and 6), and when no load is applied, the low-resilience ring-shaped body 3 returns to its original shape due to its elasticity, causing the convex portion 7 to move away from the vibration surface of the bone conduction speaker main body 5 (see Figures 3 and 4(A)).

[0021] In another embodiment, the contact 6 has elasticity. In that case, the contact 6 bends and pushes the low-resilience ring-shaped body 3 when a load is applied, so that the contact 6 comes into contact with the vibration surface of the bone-conduction speaker main body 5, and moves away from the vibration surface of the bone-conduction speaker main body 5 due to the synergistic effect of the elastic restoration of the contact 6 and the elastic restoration of the low-resilience ring-shaped body 3 when no load is applied.

[0022] In the case of the above configuration, even if an audio signal is electrically input to the bone conduction speaker main body 5, when the contact 6 is not being touched by the human body and is not in use, the contact 6 (convex portion 7) and the bone conduction speaker main body 5 are separated (see Figures 3 and 4(A)), so that the contact 6 itself does not vibrate.

[0023] As described above, the vibration generated in the bone conduction speaker body 5 is also transmitted to the housing holding the bone conduction speaker body 5, and undesirable phenomena such as ringing and sound leakage occur to some extent. That is, a vibration (arrow b in FIG. 7) is generated that is transmitted to the housing side as a reaction force of the vibration (arrow a in FIG. 7) that is transmitted to the human body as an audio signal, and the resonance of the housing and air vibration indicated by the arrow b cause ringing (arrow d in FIG. 7). However, in the case of the bone conduction speaker unit 1 according to the present invention, the vibration transmitted to the base frame 2 is reduced because the vibration-damping material 4 made of a metal material such as brass having vibration-damping properties is fixed to the side of the base frame 2 opposite to the vibration surface of the bone conduction speaker body 5. Therefore, the occurrence of resonance, sympathetic vibration, and ringing caused by the vibration of the base frame 2 (and the vibration-damping material 4) is reduced.

[0024] The headrest 11 with the built-in bone conduction speaker unit according to the present invention has the above-mentioned bone conduction speaker unit 1 built in, and the surface 12 of the headrest 11 on which the back of the user's head comes into contact is partially opened, and the opening 13 is covered with a ventilation cover 14 made of a breathable material such as a mesh material, and the bone conduction speaker unit 1 is arranged in the opening 13 so that the contact 6 is always in contact with the ventilation cover 14 (FIGS. 5 and 6). That is, the bone conduction speaker unit 1 is tightly fitted in a recess 15 formed in a cushion material 17 filled in the surface 12, and another cushion material is filled around it as necessary. In the illustrated example, a skeleton 16 is provided inside, but it may not be provided. Note that wiring extending from the bone conduction speaker unit 1 is omitted.

[0025] In this manner, the ventilation cover 14 is placed over the opening 13 provided in the skin 12 at the portion that contacts the human body (back of the head), and the bone conduction speaker unit 1 is arranged inside the ventilation cover 14 so that the contacts 6 are always in contact with the ventilation cover 14, which reduces the vibration of the contacts 6 from being transmitted to the skin 12 and reduces noise caused by the vibration of the skin 12. In addition, since the ventilation cover 14 is breathable, heat generated when the bone conduction speaker main body 5 is in operation is released. [Industrial Applicability]

[0026] The bone conduction speaker unit of the present invention is as described above. Since the bone conduction speaker unit is mounted on a vibration-damping material which is a weight, vibrations in the reverse direction are reduced. Also, since the surface area of ​​the contact with the human body is formed to be as small as possible, there is an effect of suppressing noise. In addition to the above effects, in the headrest incorporating the bone conduction speaker unit of the present invention, only the contact portion of the incorporated bone conduction speaker unit is made of a breathable cover made of a breathable material. Therefore, the transmission of vibration to the epidermis is suppressed, thereby reducing noise caused by vibration of the epidermis and enabling heat to be released, and therefore the industrial applicability is great.

Claims

1. a base frame, a low-resilience ring-shaped body fixed to an upper surface of the base frame, a vibration-damping material fitted into the base frame, a bone-conduction speaker body placed on the vibration-damping material while being surrounded by the low-resilience ring-shaped body, and a contact placed on the low-resilience ring-shaped body so as to cover the bone-conduction speaker body; The bone conduction speaker unit is characterized in that the contact comprises a pair of legs fixed on the low-resilience ring-shaped body and a bridge extending between the legs so as to bulge outward, and the contact abuts against the vibration surface on the top of the bone conduction speaker main body when a load is applied and moves away from the vibration surface of the bone conduction speaker main body when no load is applied.

2. 2. The bone conduction speaker unit according to claim 1, wherein the contact abuts against the vibration surface on the upper surface of the bone conduction speaker main body by pushing the low-resilience annular body when a load is applied, and moves away from the vibration surface of the bone conduction speaker main body as the low-resilience annular body elastically restores when no load is applied.

3. The bone conduction speaker unit of claim 1, wherein the contact is elastic and bends and pushes the low-resilience annular body when a load is applied, thereby contacting the vibration surface of the upper surface of the bone conduction speaker main body, and when no load is applied, the contact and the low-resilience annular body elastically recover to their original state and move away from the vibration surface of the bone conduction speaker main body.

4. 4. The bone conduction speaker unit according to claim 1, wherein the contact has a convex portion that abuts against the vibration surface on the top surface of the bone conduction speaker body when a load is applied and that moves away from the vibration surface of the bone conduction speaker body when no load is applied.

5. 2. The bone conduction speaker unit according to claim 1, wherein the bridge is cross-shaped in a plan view and is as hollowed out as possible.

6. A headrest incorporating the bone conduction speaker unit according to any one of claims 1 to 5, A headrest with a built-in bone conduction speaker unit, characterized in that an opening is formed in the surface of the headrest that contacts the rear of the head, a ventilation cover is attached to the opening, and the bone conduction speaker unit is arranged inside the opening so that the contact is always in contact with the ventilation cover.

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