Microphone

A microphone is provided that prevents or reduces generation of noises caused by vibration from a grip body. A microphone includes a grip body having a shape of a cylinder, a head case attached to the grip body, a microphone unit disposed inside the head case, an internal cylinder to which the microphone unit is attached, and an elastic member configured to undergo shear deformation in the longitudinal direction of the grip body. The internal cylinder is disposed inside the grip body with the elastic member.

TECHNICAL FIELD

The present invention relates to a microphone.

BACKGROUND ART

Some microphones are handheld microphones used for vocal performance. The handheld microphone includes, for example, a grip body having a shape of a cylinder and a microphone unit (hereinafter referred to as “unit”) supported at one end of the grip body.

When used, the handheld microphone is gripped by a user at the grip body serving as a grip. When the handheld microphone is used by the user, vibration can be caused by shaking of the hands of the user or by dropping the microphone from the hands of the user. Such vibration is transmitted from the grip body to the unit. As a result, the handheld microphone can generate undesired noises.

With respect to techniques for preventing the transmission of vibration to the unit, techniques have been proposed to attach the unit to an internal cylinder supported inside the grip body that is isolated from vibration by shock mounts (for example, refer to Japanese Patent No. 4411112).

The microphone disclosed in Japanese Patent No. 4411112 includes a grip body having a shape of a cylinder, a cavity sleeve (internal cylinder) having a shape of a cylinder, a unit, shock mounts, and a pressing ring having a shape that is substantially cylindrical. The internal cylinder is disposed inside the grip body. The internal cylinder has a flange portion. The flange portion is disposed on the outer circumferential surface of the internal cylinder. The unit is attached to the front end portion of the internal cylinder.

The shock mounts are disposed between the grip body and the internal cylinder and prevent transmission of vibration from the grip body to the internal cylinder. The shock mounts are composed of elastic rubber. The shock mounts include a front shock mount and a rear shock mount.

The front shock mount has a shape that is substantially cylindrical. The front shock mount is attached to the outer circumferential surface of the front portion of the internal cylinder. The rear end surface of the front shock mount is in contact with the flange portion of the internal cylinder. The pressing ring is disposed so as to cover the outer circumferential surface of the front shock mount. The front end of the pressing ring is turned inward. The inner surface of the turned pressing ring is in contact with the front end surface of the front shock mount.

The rear shock mount has a shape of a hollow cylinder with a closed end. The rear shock mount is attached to the rear end of the internal cylinder.

As described above, the internal cylinder to which the unit is attached is supported by the two shock mounts attached to the front portion and the rear end of the internal cylinder. The internal cylinder is isolated from vibration by the two shock mounts. That is, vibration from the grip body to the internal cylinder is damped by the elasticity of the shock mounts.

SUMMARY OF INVENTION

Technical Problem

When the contact area between the shock mounts and the internal cylinder is large, the vibration from the grip body is transmitted to the internal cylinder via the shock mounts as longitudinal waves. In general, the front shock mount is attached near the unit. Thus, the front shock mount transmits vibration to the unit more readily than the rear shock mount.

As described above, the front shock mount has a shape that is substantially cylindrical. The inner circumferential surface of the front shock mount is in tight contact with the outer circumferential surface of the internal cylinder over a relatively large area. When a force in the front-back direction is applied to the front shock mount, the front shock mount is compressed in the front-rear direction. Thus, the degree of contact between the inner circumferential surface of the front shock mount and the outer circumferential surface of the internal cylinder increases. As a result, the vibration from the grip body is transmitted to the unit via the front shock mount and the internal cylinder as longitudinal waves. The microphone to which the vibration is transmitted generates noises.

An object of the present invention is to solve the problems described above and to prevent or reduce generation of noises caused by vibration from the grip body.

Solution to Problem

The microphone according to the present invention includes a grip body having a shape of a cylinder, a head case attached to the grip body, a microphone unit disposed inside the head case, an internal cylinder to which the microphone unit is attached, and an elastic member configured to undergo shear deformation in the longitudinal direction of the grip body. The internal cylinder is disposed inside the grip body with the elastic member.

The microphone according to the present invention can prevent or reduce generation of noises caused by vibration from the grip body.

DESCRIPTION OF EMBODIMENTS

Microphone

Embodiments of a microphone according to the present invention will now be described with reference to the attached drawings.

Configuration of Microphone

FIG. 1is a front view illustrating an embodiment of a microphone according to the present invention.

A microphone1collects acoustic waves from a sound source (not shown). The microphone1is a handheld microphone.

FIG. 2is a cross-sectional view of the microphone1taken along line A-A ofFIG. 1.

FIG. 3is an exploded cross-sectional view of the microphone1.

The microphone1includes a grip body10, a head case20, a head-case attaching member30, a screw40, a microphone unit (hereinafter referred to as “unit”)50, an internal cylinder60, a first elastic member70, a second elastic member80, an output connector90, and a name ring100.

In the description below, the direction to which the microphone1is directed during sound collection (the upper side ofFIG. 2) is referred to as “front.”

The grip body10functions as a grip of the microphone1. The grip body10is composed of metal, such as brass, for example. The grip body10is manufactured by die-casting, for example. The grip body10has a shape of a cylinder. The outer diameter of the grip body10gradually increases from the rear portion (the lower portion in the grip body10ofFIG. 2) of the grip body10to the front portion (the upper portion in the grip body10ofFIG. 2) of the grip body10. The grip body10includes a fixing portion11, a connector accommodating portion12, a fitting portion13, and a side-cut portion14.

The fixing portion11is disposed in the front portion of the grip body10. The fixing portion11fixes the head-case attaching member30. The outer and inner diameters of the fixing portion11are constant. The fixing portion11has a screw insertion hole11h. The screw insertion hole11his disposed in the circumferential wall of the fixing portion11. The screw40is inserted into the screw insertion hole11h.

The connector accommodating portion12is disposed in the rear portion of the grip body10. The connector accommodating portion12accommodates the output connector90. The inner diameter of the connector accommodating portion12is smaller than the inner diameters of other portions of the grip body10. The connector accommodating portion12has a tool insertion hole12hdescribed below. The tool insertion hole12his disposed in the circumferential wall of the connector accommodating portion12.

The fitting portion13is disposed in a portion of the grip body10adjacent to the front end of the connector accommodating portion12. The fitting portion13fits with the second elastic member80. The inner diameter of the fitting portion13is larger than the inner diameter of the connector accommodating portion12.

The side-cut portion14is disposed on the outer circumferential surface of the grip body10. The side-cut portion14enhances the fitting when a user grips the grip body10of the microphone1. The side-cut portion14is a flat region formed along the front-back direction.

The head case20accommodates and protects the unit50. The head case20includes a case portion21and a fixing portion22. The case portion21protects the unit50. The case portion21has a three-layer structure consisting of a steel outer grill, a metal mesh (not shown), and a urethane foam (not shown), for example. The case portion21has a shape of a barrel with an open rear end. The fixing portion22fixes the case portion21to the head-case attaching member30. The fixing portion22has a shape of a ring. The fixing portion22is attached to the rear end (open end) of the case portion21. The fixing portion22has an internally threaded portion22a. The internally threaded portion22ais disposed on the inner circumferential surface of the fixing portion22.

The head-case attaching member30fixes the head case20to the grip body10. The head-case attaching member30is composed of metal, such as brass, for example. The head-case attaching member30has a shape of a substantial cylinder. The head-case attaching member30has an externally threaded portion30aand an internally threaded hole30h. The externally threaded portion30ais disposed on the outer circumferential surface of the central portion of the head-case attaching member30in the front-back direction. The internally threaded hole30his disposed in the circumferential wall of the rear half of the head-case attaching member30. The screw40is screwed into the internally threaded hole30h.

The screw40fixes the head-case attaching member30to the grip body10. The screw40is a flat head screw, for example.

The unit50collects acoustic waves from the sound source. The unit50is a unidirectional dynamic microphone unit, for example.

The directivity of the unit50is not limited to unidirectivity. The type of the unit50is not limited to a dynamic type. Rather, unit50can be of any desired type for the application.

The internal cylinder60supports the unit50and defines an air chamber A described below inside the internal cylinder60. The internal cylinder60is composed of metal, such as brass, for example. The internal cylinder60is manufactured by die-casting, for example. The internal cylinder60has a shape of a cylinder. The internal cylinder60has a flange portion61and a partition62. The flange portion61is disposed on the outer circumferential surface of the front half of the internal cylinder60and protrudes along the entire circumference from the outer circumferential surface of the internal cylinder60in radial direction. The flange portion61will be described below. The partition62is disposed on the inner circumferential surface of the rear half of the internal cylinder60. The partition62separates the internal space of the internal cylinder60into front and rear sections. The partition62has an insertion hole62h. A cable (not shown) configured to connect electrically the unit50and the output connector90is to be inserted through the insertion hole62h.

The first elastic member70prevents transmission of vibration from the grip body10to the internal cylinder60supporting the unit50. The first elastic member70is one example of a suitable elastic member of the microphone according to the present invention. The first elastic member70is composed of elastic synthetic resin, such as rubber, for example. The first elastic member70has a shape of a ring.

FIG. 4is an enlarged cross-sectional view of the first elastic member70.

The first elastic member70has skin layers71and depressions72. The skin layers71are a front end face70a(top surface) of the first elastic member70and a rear end face70b(bottom surface) of the first elastic member70which are formed by thermal curing of the surfaces of the first elastic member70. The modulus of elasticity of the skin layers71is larger than the modulus of elasticity of a portion other than the skin layers71(hereinafter referred to as “elastic portion”) of the first elastic member70.

The skin layers may be a component separate from the first elastic member. That is, the skin layers may be attached to the front end face and the rear end face of the first elastic member. In such a case, the modulus of elasticity of the skin layers is larger than the modulus of elasticity of the first elastic member. The skin layer should be attached to at least one of the front end face and the rear end face of the first elastic member.

The outer diameter of the skin layers71is larger than the outer diameter of the flange portion61of the internal cylinder60. The outer diameter of the skin layers71is substantially identical to the inner diameter of the fixing portion11of the grip body10.

The elastic portion has a shape of an hourglass narrow in the middle in the front-back direction (the vertical direction inFIG. 4) in a cross-sectional view. That is, the outer diameter of the elastic portion gradually decreases along the front-back direction, from the two skin layers71toward the central area of the elastic portion. The inner diameter of the elastic portion of the first elastic member70gradually increases along the front-back direction (the vertical direction inFIG. 4), from the two skin layers71toward the central area of the elastic portion. In other words, the depressions72extend around the entire outer circumferential surface and the entire inner circumferential surface of the first elastic member70.

The depression72should extend around at least one of the entire outer circumferential surface or the entire inner circumferential surface of the first elastic member70.

The second elastic member80prevents transmission of vibration from the grip body10to the internal cylinder60holding the unit50. The second elastic member80is composed of elastic synthetic resin, such as rubber, for example. As shown inFIGS. 2 and 3, the second elastic member80has a shape of a double cylinder having a rear end bent into a U-shape in cross-section.

The output connector90is, for example, an output connector conforming to JEITA Standard RC-5236 “Circular Connectors, Latch Lock Type for Audio Equipment.” As shown inFIG. 3, the output connector90includes a base91having a shape of a column, a shield cover92having a shape of a hollow cylinder with a closed end, a first pin for ground (not shown), a second pin93for hot signals, a third pin94for cold signals, and an external screw95.

The base91has an internally threaded hole91aextending from the outer circumferential surface of the base91in the radial direction of the base91. The external screw95is screwed into the internally threaded hole91a. The shield cover92is disposed so as to cover the base91. The shield cover92covers the front surface of the base91and the circumferential surface of the base91other than the internally threaded hole91a. The first pin, the second pin93, and the third pin94penetrate the base91and the shield cover92in the front-back direction. The outer diameter of the head of the external screw95is smaller than the outer diameter of the threaded portion of the external screw95and the inner diameter of the tool insertion hole12hof the grip body10. The external screw95has a stepped shoulder portion disposed between the threaded portion and the head of the external screw95.

The name ring100covers the fixing portion11of the grip body10and the screw40to improve the external appearance of the microphone1. The name ring100is composed of metal, for example, and has a shape that is substantially cylindrical.

Among the components of the microphone1, the head-case attaching member30, the unit50, the internal cylinder60, the first elastic member70, and the second elastic member80constitute a first assembly. The first assembly, the grip body10, and the output connector90constitute a second assembly.

Method of Manufacturing Microphone

A method of assembling (manufacturing) the microphone1will now be described.

FIG. 5is an exploded cross-sectional view of a first assembly of the microphone1.

FIG. 6is a cross-sectional view of the first assembly of the microphone1.

FIG. 7is an exploded cross-sectional view of a second assembly of the microphone1.

FIG. 8is a cross-sectional view of the second assembly of the microphone1.

First, the first assembly is assembled from the head-case attaching member30, the internal cylinder60, the first elastic member70, and the second elastic member80.

The first elastic member70is attached to the outer circumferential surface of the internal cylinder60from the front of the internal cylinder60. The inner circumferential surfaces of skin layers71of the first elastic member70are in contact with the outer circumferential surface of the internal cylinder60. A part of the rear end face70bof the first elastic member70is in contact with the flange portion61of the internal cylinder60. That is, the position of the first elastic member70relative to the internal cylinder60is determined by the flange portion61. The second elastic member80is fit with the rear end of the internal cylinder60.

The head-case attaching member30is attached to the internal cylinder60from the front of the internal cylinder60. The rear end of the head-case attaching member30is in contact with a part of the front end face70aof the first elastic member70. A gap is formed between the inner circumferential surface of the head-case attaching member30and the outer circumferential surface of the internal cylinder60.

Then, the unit50is attached to the internal cylinder60. The rear portion of the unit50is fit in the opening of the front end of the internal cylinder60. That is, the unit50is attached to the front end of the internal cylinder60. The rear end of the unit50, the internal cylinder60, and the partition62of the internal cylinder60define the air chamber A of the unit50inside the internal cylinder60.

Then, the first assembly and the output connector90are attached to the grip body10to assemble the second assembly.

The first assembly is inserted into the grip body10from the front of the grip body10. The rear end of the second elastic member80is fit with a fitting portion13of the grip body10. The screw40is inserted into the screw insertion hole11hof the grip body10. The screw40inserted into the screw insertion hole11his screwed into the internally threaded hole30hof the head-case attaching member30. That is, the first assembly is screwed to the grip body10with the screw40.

Then, the output connector90is accommodated in the connector accommodating portion12from the rear of the grip body10. The external screw95is preliminarily screwed into the internally threaded hole91aof the base91of the output connector90. The external screw95of the output connector90accommodated in the connector accommodating portion12is screwed out from the internally threaded hole91awith a driver inserted into the tool insertion hole12h, for example. The head of the external screw95is inserted into the tool insertion hole12h. The shoulder portion of the external screw95is in contact with the inner circumferential surface of the connector accommodating portion12. Thus, the base91is pressed by the external screw95in the direction opposite to the direction (the direction toward the right inFIG. 7) of the screwing out of the external screw95. As a result, the shield cover92of the output connector90is pressed toward the inner circumferential surface of the grip body10.

The unit50is preliminarily connected to the output connector90with the cable before the assembly of the first assembly. The cable is inserted through an insertion hole62hof the partition62of the internal cylinder60and into the internal cylinder60.

One end of the cable may be preliminarily connected to the unit50before the assembly of the second assembly, and the other end may be connected to the output connector90at the assembly of the second assembly.

Then, the name ring100and the head case20are attached to the second assembly.

FIG. 9is an exploded cross-sectional view of the second assembly and the components attached to the second assembly of the microphone1.

The name ring100is attached to the outer circumferential surface of the fixing portion11of the grip body10from the front of the second assembly. The screw40is shielded from the exterior by the name ring100.

Then, the head case20is attached to the head-case attaching member30from the front of the second assembly. The externally threaded portion30aof the head-case attaching member30is screwed into the internally threaded portion22aof the fixing portion22of the head case20. That is, the head case20is attached to the grip body10with the head-case attaching member30. The unit50is disposed inside the head case20.

The microphone1is assembled as described above into a finished product shown inFIG. 2. The internal cylinder60of the microphone1is disposed inside the grip body10with the first elastic member70and the second elastic member80. That is, the internal cylinder60is supported inside the grip body10and isolated from vibration by the first elastic member70and the second elastic member80.

Contact State of First Elastic Member and Other Components

The contact state of the first elastic member70and the other components of the microphone1will now be described.

FIG. 10is an enlarged cross-sectional view of main components of the microphone1. InFIG. 10, the shearing force (described below) received by the first elastic member70is illustrated by white arrows.

The outer circumferential surfaces of the skin layers71of the first elastic member70are in contact with the inner circumferential surface of the grip body10. That is, the outer circumferential surface of the first elastic member70is in contact with the inner circumferential surface of the grip body10at only the skin layers71and portions adjacent to the skin layers71in the elastic portion. In other words, the first elastic member70is in contact with the grip body10in a small contact area. Thus, transmission of vibration from the grip body10to the first elastic member70is prevented in the microphone1.

The inner circumferential surfaces of the skin layers71of the first elastic member70are in contact with the outer circumferential surface of the internal cylinder60. That is, the inner circumferential surface of the first elastic member70is in contact with the outer circumferential surface of the internal cylinder60at only the skin layers71and portions adjacent to the skin layers71in the elastic portion. In other words, the first elastic member70is in contact with the internal cylinder60in a small contact area. Thus, transmission of vibration from the first elastic member70to the internal cylinder60is prevented in the microphone1.

An outer circumferential portion of the front end face70aof the first elastic member70is in contact with the rear end face of the head-case attaching member30. That is, the head-case attaching member30is in contact with the outer circumferential portion of the first elastic member70. An inner circumferential portion of the rear end face70bof the first elastic member70is in contact with the flange portion61of the internal cylinder60. That is, the flange portion61is in contact with the inner circumferential portion of the first elastic member70. In other words, the first elastic member70is supported diagonally by the head-case attaching member30and the flange portion61.

In this structure, the first elastic member70receives a shearing force in the front-back direction, when the force in the front-back direction (the vertical direction inFIG. 10) is applied to the first elastic member70by the head-case attaching member30and the flange portion61. That is, the inner circumferential surface of the first elastic member70receives a shearing force in the direction (the direction toward the upper side inFIG. 10) toward the front where the unit50is disposed from the flange portion61. On the other hand, the outer circumferential surface of the first elastic member70receives a shearing force in the direction (the direction toward the lower side inFIG. 10) toward the back from the head-case attaching member30.

The first elastic member70also receives a compressing force in the front-back direction. As described above, the depressions72extend around the entire inner circumferential surface and the entire outer circumferential surface of the first elastic member70. The first elastic member70is supported diagonally by the head-case attaching member30and the flange portion61. Thus, a high shearing force is applied to the first elastic member70in the front-back direction. As a result, the first elastic member70undergoes shear deformation in the front-back direction. Accordingly, the first elastic member70undergoes shear deformation in the front-back direction, that is, in the longitudinal direction of the grip body10, to support and isolate the internal cylinder60from vibration.

CONCLUSION

According to the embodiments described above, the internal cylinder60supporting the unit50is disposed inside the grip body10with the first elastic member70configured to undergo shear deformation in the front-back direction. Thus, the degree of contact between the first elastic member70and the internal cylinder60is substantially unvaried when the force is applied to the first elastic member70in the front-back direction. As a result, the microphone1does not generate noises or reduces the amount of noises caused by vibration from the grip body10.

The depression72extends around the entire inner circumferential surface of the first elastic member70. The contact area between the first elastic member70having the depression72and the internal cylinder60is smaller than the contact area between the elastic member and the internal cylinder of a conventional microphone in which the substantially entire inner circumferential surface of the elastic member is in contact with the outer circumferential surface of the internal cylinder. On the other hand, the depression72extends around the entire outer circumferential surface of the first elastic member70. The contact area between the first elastic member70having the depression72and the grip body10is smaller than the contact area between the elastic body and the grip body of the conventional microphone. As a result, the first elastic member70readily undergoes shear deformation in the front-back direction, when the force is applied to the first elastic member70in the front-back direction. The elastic portion of the first elastic member70does not come into tight contact with the internal cylinder60, when the force is applied to the first elastic member70in the front-back direction. As a result, the microphone1does not generate noises or reduces the amount of noises caused by vibration from the grip body10, compared to the conventional microphone.

The first elastic member70is supported diagonally by the head-case attaching member30and the flange portion61. Thus, the first elastic member70readily receives a shearing force in the front-back direction when the force is applied to the first elastic member70in the front-back direction. As a result, the microphone1does not generate noises or reduces the amount of noises caused by vibration from the grip body10.

The first elastic member70has the skin layers71on the front end face70aand the rear end face70bof the first elastic member70. The modulus of elasticity of the skin layers71is larger than the modulus of elasticity of the elastic portion. Thus, the skin layers71press diagonally the elastic portion without a significant deformation, when the force is applied to the first elastic member70in the front-back direction. As a result, the elastic portion readily undergoes shear deformation in the front-back direction. As a result, the microphone1does not generate noises or reduces the amount of noises caused by vibration from the grip body10.