JP2007043610A - Speaker diaphragm and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a speaker diaphragm and its manufacturing method which optimizes the sound quality and increases the bending rigidity without being subjected to the limit of the division number of the entire circumference of the diaphragm. <P>SOLUTION: The speaker diaphragm is formed with first prepreg pieces formed by cutting a carbon prepreg sheet 100 into a sector so that radial directions of the sector intersect the fiber directions of the prepreg sheet 100 and second prepreg pieces formed by the carbon prepreg sheet 100 so that radial directions of the sector are equal to the fiber directions of the prepreg sheet 100. The diaphragm has a lower layer 2 formed by laying the first prepreg pieces overlapped with each other, laminating one layer or more and forming the entire circumference of the diaphragm with arcuate portions of the prepreg pieces, and a multilayer upper layer 3 formed by laying the second prepreg pieces overlapped with each other and forming the entire circumference of the diaphragm with arcuate portions of the prepreg pieces. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a speaker diaphragm containing carbon fiber and a method for manufacturing the same.

  Some speaker diaphragms containing carbon fibers are manufactured using a carbon prepreg sheet. As shown in FIG. 16 (a), the carbon prepreg sheet 100 can be bent or cut by aligning carbon fibers 101 in one direction and impregnating a semi-cured thermosetting resin such as an epoxy resin. It is a sheet. In the following, the carbon prepreg sheet 100 of FIG. 16A is expressed as follows. As shown in FIG. 16B, the carbon fiber 101 is represented by a straight line, and the direction in which the carbon fibers 101 are aligned is represented by a fiber direction D. As a speaker diaphragm using such a carbon prepreg sheet 100, there is the following (Patent Document 1). In this speaker diaphragm, as shown in FIG. 17, a prepreg strip formed by cutting the carbon prepreg sheet 100 into a strip shape so that the fiber direction D of the carbon fiber 101 is the same as the radial direction of the diaphragm. A piece 110 is used. That is, with respect to the male mold 201 shown in FIG. 9, as shown in FIG. 18, the longitudinal direction of the prepreg strips 110 is set to be the radial direction of the diaphragm, and the prepreg strips 110 are radially stacked. Thereafter, the female mold 202 (FIG. 9) is superposed on the male mold 201, and press-molded while heating. Thus, a speaker diaphragm using the carbon prepreg sheet 100 is manufactured.

Moreover, the following speaker diaphragms using the carbon prepreg sheet 100 are also available (Patent Document 2). In this speaker diaphragm, as shown in FIG. 19, a sheet piece 121 formed by cutting the carbon prepreg sheet 100 into a trapezoidal shape so that the fiber direction D is the same as the radial direction of the diaphragm is used. ing. That is, with respect to the male mold 201 (FIG. 9), as shown in FIG. 20, the sheet piece 121 (the sheet indicated by the solid line) is formed such that the side edges of the sheet piece 121 overlap with each other to form a joint portion 121A. Place the piece) to form the inner sheet. Further, the outer sheet is then formed in the same manner as the inner sheet so that another sheet piece 121 (a sheet piece indicated by a broken line) covers the joint portion 121A of the inner sheet. Thereafter, the female mold 202 (FIG. 9) is superposed on the male mold 201, and press-molded while heating. Thus, a speaker diaphragm having a two-layer structure of an inner sheet and an outer sheet is manufactured using the carbon prepreg sheet 100.
JP-A 64-37199 JP 58-220598 A

  However, the manufacturing method of the speaker diaphragm using the carbon prepreg sheet has the following problems. When using prepreg strips formed by cutting carbon prepreg sheets into strips (Patent Document 1), the mutual overlap width at the inner periphery of the speaker diaphragm is larger than the overlap width at the outer periphery. A prepreg strip is placed on the top. That is, the inner periphery is thicker than the outer periphery. For this reason, in order to overlap the prepreg strips so that there is no gap between adjacent prepreg strips on the outer periphery of the speaker diaphragm and there is no gap between the prepreg strips on the inner periphery, Depending on the width of the strip and the distance from the outer peripheral portion to the inner peripheral portion of the speaker diaphragm, the size of the prepreg strip is limited.

  For example, when manufacturing a cone having a large diameter, if the aspect ratio of the prepreg strip is increased and the overlap at the inner periphery is made appropriate, a gap is formed between the prepreg strips at the outer periphery, and the aspect ratio is reduced. Large prepreg strips cannot be used. As a result, it is necessary to reduce the aspect ratio of the prepreg strip, but the number of divisions on the entire circumference of the cone is limited, and the degree of freedom in appearance and sound quality are limited.

  The manufacturing method of the speaker diaphragm using the prepreg strips has the above-described problems. The manufacturing method of the speaker diaphragm using the sheet pieces formed by cutting into a trapezoidal shape (Patent Document 2) is as follows. There is a problem. That is, when cutting into a trapezoidal sheet piece, only the radial direction of the speaker diaphragm is set to the fiber direction. For this reason, optimization of sound quality and the bending rigidity of the diaphragm for speakers cannot be sufficiently improved, and development to a large-diameter speaker is difficult. In addition, since the fiber direction is a trapezoidal height direction, an arbitrary point on both side surfaces becomes a fiber break, causing acoustic vibration propagation loss.

  The present invention solves the above-described problems, and provides a speaker diaphragm and a manufacturing method thereof that can optimize sound quality and increase bending rigidity without being limited by the number of divisions on the entire circumference of the diaphragm. is there.

In order to solve the above-described problem, the invention of claim 1 is configured such that the carbon prepreg sheet 100 is fan-shaped and the direction intersecting the radial direction of the fan-shape is the fiber direction D of the carbon prepreg sheet 100. For speakers formed by cutting a first prepreg piece 10 and a second prepreg piece 20 formed by cutting the carbon prepreg sheet 100 so that the radial direction is the fiber direction D. A first prepreg layer, which is a diaphragm and is arranged so that the first prepreg pieces 10 overlap each other and forms the entire circumference of the diaphragm by an arc portion of each first prepreg piece 10, is 1 The first layer portion 2 and the second prepreg piece 20 that are stacked in layers are arranged so as to overlap each other, and are vibrated by the arc portion of each prepreg piece 20. The second prepreg layer forming the entire circumference of the second prepreg layer is provided with a second layer portion 3 in which one or more layers are stacked, the first layer portion 2 is a lower layer, and the second layer portion 3 is an upper layer. It is the diaphragm for speakers characterized by these.
According to a second aspect of the present invention, in the speaker diaphragm according to the first aspect, the first and second layer portions 2 and 3 are laminated on a mount C.
The invention according to claim 3 is the first prepreg piece by cutting the carbon prepreg sheet 100 into a fan shape and the direction intersecting the radial direction of the fan shape is the fiber direction D of the carbon prepreg sheet 100. 10, the carbon prepreg sheet 100 is cut to form the second prepreg piece 20 so that the radial direction is the fiber direction D, and the first prepreg pieces 10 are arranged so as to overlap each other. In addition, one or more first prepreg layers that form the entire circumference of the diaphragm are formed by the arc portion of each prepreg piece 10 to form the first layer portion 2, and the second prepreg piece 20 and the second prepreg layer that forms the entire circumference of the diaphragm by the arc portion of each prepreg piece 20 is laminated to form a second layer. Part 3 was formed, the first layer 2 and the lower layer is a method for producing a speaker diaphragm, characterized by laminating the second layer portion 3 as the upper layer.
According to a fourth aspect of the present invention, in the method for manufacturing a speaker diaphragm according to the third aspect, the first and second layer portions 2 and 3 are laminated on a mount C.
According to a fifth aspect of the present invention, in the method for manufacturing a speaker diaphragm according to the third aspect, the prepreg pieces 20 constituting the second layer portion 3 are laminated so that substantially half of the prepreg pieces 20 overlap each other. And
A sixth aspect of the present invention is the method of manufacturing a speaker diaphragm according to the third aspect, wherein the prepreg pieces 10 constituting the first layer portion 2 are laminated so that substantially half of the prepreg pieces 10 overlap each other. And

According to the first to fourth aspects of the present invention, when the carbon prepreg sheet is cut into a trapezoid as in the prior art, the prepreg piece is compared with a cutting method in which the height direction of the trapezoid is set to the fiber direction. A prepreg piece is cut from the carbon prepreg sheet so that the straight part of the is parallel to the fiber direction. Thereby, the cut | interruption of a carbon fiber can be decreased compared with the past, and the loss of acoustic vibration propagation can be avoided.
Moreover, since the prepreg pieces are cut into a fan shape and the prepreg pieces are overlapped at a constant interval, the width of the prepreg pieces to be cut is arbitrary, and the number of divisions can be set freely without depending on the shape of the diaphragm. And the degree of design freedom can be secured. In addition, the rigidity of the diaphragm can be increased by arranging the first layer portion in which the fiber direction is the circumferential direction of the diaphragm, compared to the prior art in which the fiber direction is only the radial direction, Enables deployment to large-diameter speakers. In addition, the sound can be broadened by improving the acoustic vibration transmissibility in the circumferential direction.
Further, when the carbon prepreg sheet is cut into a trapezoid as in the prior art, the second layer portion 3 for the upper layer has a prepreg piece as compared with the cutting method in which the height direction of the trapezoid is in the fiber direction. The prepreg piece 20 is cut from the carbon prepreg sheet so that the 20 straight portions are substantially parallel to the fiber direction D. Thereby, the cut | interruption of a carbon fiber can be decreased compared with the past, and the loss of acoustic vibration propagation can be avoided.
In addition, since the fiber direction of the first layer portion, which is the lower layer, is substantially the circumferential direction, and the fiber direction of the second layer portion, which is the upper layer, is the substantially radial direction, the rigidity is improved, and the sound is substantially circumferential, Since it is propagated in the radiation direction, the spread of sound can be obtained.
Further, if the first and second layer portions are laminated on the mount, the rigidity can be further improved, and ideal acoustic properties can be obtained by the combination thereof.
According to the fifth and sixth aspects of the invention, in addition to the above-described effects of the third and fourth aspects of the invention, since almost half of the prepreg pieces 10 and 20 are overlapped, a two-layer structure is easily formed in the process. Obtainable.

Next, embodiments of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
The speaker diaphragm according to this embodiment is a schematic view of a cone-shaped diaphragm 1A having a three-layer structure as shown in FIG. This three-layer structure is composed of a lower layer portion 2 and an upper layer portion 3. That is, in this example, the lower layer part 2 is composed of only the first layer 2A, and the upper layer part 3 is composed of two layers of the first layer 3A and the second layer 3B. That is, the first layer 2A of the lower layer 2 is overlapped as the first layer, and the first layer 3A and the second layer 3B of the upper layer 3 are stacked as the second layer. The first layer 2A of the lower layer part 2, the first layer 3A and the second layer 3B of the upper layer part 3 are formed from the carbon prepreg sheet 100 shown in FIG. 16 as follows.

  In this embodiment, a fan-shaped prepreg piece 10 is cut out from the carbon prepreg sheet 100 as shown in FIG. The prepreg piece 10 includes an arc portion 11, a linear portion 12 that is spaced from and faces the arc portion 11, a linear portion 13 that connects one end of the arc portion 11 and one end of the linear portion 12, and a straight line between the other end of the arc portion 11. It has a fan shape surrounded by a straight portion 14 connecting the other end of the portion 12. In this fan shape, the straight portions facing each other are the straight portions 13 and 14. Then, the direction intersecting the radial direction of the fan-shaped arc portion 11 is the fiber direction D of the carbon prepreg sheet 100, that is, in this embodiment, the straight portion 13 intersects the fiber direction D substantially at a right angle. The prepreg piece 10 is cut out from the carbon prepreg sheet 100 so that the prepreg sheet 100 is oriented. The prepreg piece 10 shown in FIG. 3 is obtained by such cutting of the carbon prepreg sheet 100. The central angle A is the central angle of the fan-shaped prepreg piece 10, that is, the central angle with respect to the arc portion 11.

  In other words, when the prepreg pieces 10 of FIG. 2 are joined by overlapping their edges so as to form a circle, the fiber direction D is substantially the circumferential direction, which is used for the lower layer.

  Moreover, in this embodiment, as shown in FIG. 4, the prepreg piece 20 is cut out from the carbon prepreg sheet 100 shown in FIG. The prepreg piece 20 has substantially the same fan shape as the prepreg piece 10 of FIG. That is, the prepreg piece 20 includes an arc portion 21, a straight portion 22 that faces the arc portion 21, a straight portion 23 that connects one end of the arc portion 21 and one end of the straight portion 22, and the other end and the straight portion of the arc portion 21. The fan is surrounded by a straight line portion 24 connecting the other end of 22. In this fan shape, the straight portions facing each other are the straight portions 23 and 24. In the case of this embodiment, the prepreg piece 20 is cut out from the carbon prepreg sheet 100 so that the straight line portion 23 is in the fiber direction D. The prepreg piece 20 shown in FIG. 5 is obtained by such cutting of the carbon prepreg sheet 100. The central angle B is the central angle of the fan-shaped prepreg piece 20, that is, the central angle with respect to the arc portion 21.

  And, when the prepreg pieces 20 shown in FIG. 4 are circular and the prepreg pieces 20 adjacent to each other are joined together by overlapping almost half or edges, the fiber direction D becomes the radial direction, This is used for the upper layer.

  As described above, the first layer 2A of the lower layer portion 2 is formed by the circular assembly of the prepreg pieces 10 of FIG. In addition, below, since the several prepreg piece 10 is used, in order to distinguish each prepreg piece 10, it describes like prepreg piece 10A, 10B. That is, as shown in FIG. 6, the straight portion 13A of the prepreg piece 10A is set to the radial direction of the cone-shaped diaphragm 1A, and the fiber direction D of the prepreg piece 10A is set to the substantially circumferential direction of the cone-shaped diaphragm 1A. Further, the arc portion 11A of the prepreg piece 10A is used as the circular edge of the cone-shaped diaphragm 1A. The next prepreg piece 10B is arranged next to the prepreg piece 10A thus arranged. At this time, the next prepreg piece 10B is arranged so that the edge portion on the straight line portion 13B side of the next prepreg piece 10B overlaps the edge portion on the straight line portion 14A side of the prepreg piece 10A. In this way, the prepreg pieces 10 are arranged so that the edge portions of the adjacent linear portions overlap each other, and each arc portion 11 of the prepreg piece 10 forms the entire circumference of the cone-shaped diaphragm 1A, and the prepreg piece 10 is used. The first layer 2A of the lower layer part 2 is formed.

  The first layer 3A of the upper layer part 3 is formed by the prepreg piece 20 as follows. That is, as shown in FIG. 7, the linear portion 23A of the prepreg piece 20A is set to the radial direction of the cone-shaped diaphragm 1A, and the fiber direction D of the prepreg piece 20A is set to the substantially radial direction of the cone-shaped diaphragm 1A. Further, the arc portion 21A of the prepreg piece 20A is used as the circular edge of the cone-shaped diaphragm 1A. The next prepreg piece 20B is arranged next to the prepreg piece 20A thus arranged. As an example of this arrangement, the next prepreg piece 20B is overlapped with the prepreg piece 20A so that the straight portion 23B of the next prepreg piece 20B preferably overlaps the prepreg piece 20A at a position approximately half the center angle B with respect to the arc portion 21A of the prepreg piece 20A. When the piece 20B is arranged, it becomes two layers. That is, when the prepreg pieces 20A and 20B are arranged in the circumferential direction, substantially half of each other overlap. Thus, the prepreg pieces 20 are arranged so that the adjacent prepreg pieces 20B overlap the prepreg pieces 20A, and each arc portion 21 of the prepreg piece 20 forms the entire circumference of the cone-shaped diaphragm 1A. The upper layer part 3 of the used two-layer structure is formed. The cross section of the upper layer part 3 in FIG. 1 is schematically shown.

  FIG. 8 shows a plan view thereof.

  In this embodiment, as described above, almost half of the prepreg pieces 20A and 20B are overlapped and integrated, and according to this manufacturing method, a two-layer structure can be easily formed in the overlapping process. it can.

  For example, the lower layer 2 and the upper layer 3 of the two-layer structure formed in this manner are arranged by stacking the prepreg strips 110 in the order of the upper layer 3 and the lower layer 2 on the male mold 201 shown in FIG. If the female mold 202 is overlaid on the male mold 201 and pressure-molded while being heated, the speaker diaphragm 1A using the carbon prepreg sheet 100 can be manufactured in this way.

  In this case, it is possible to use as the speaker diaphragm 1A in the lower layer portion 2 and the upper layer portion 3 of the two-layer structure, but as shown in FIG. 10, on the cone-shaped mount C produced by the papermaking method, When the prepreg strips 110 of the lower layer part 2 and the upper layer part 3 are laminated and integrated, a sufficient rigidity and ideal acoustic properties are obtained by the mount C, which is preferable. That is, since the backing C having a high internal loss is used on the back side of the diaphragm 1A and the carbon prepreg sheet having a high elastic modulus (fast sound speed) is used on the surface side (sound radiation surface side), ideal acoustic properties are obtained. can get.

  As is well known, a voice coil (not shown) is attached to the neck of the speaker diaphragm 1A, the voice coil is disposed in the magnetic gap of the magnetic circuit, and the speaker diaphragm 1A is mounted in the frame. Thus, a speaker can be configured.

  FIG. 11 shows the frequency characteristics of a speaker with a diameter of 16 cm provided with the speaker diaphragm 1A of this embodiment having a multilayer structure using the mount C.

  According to this embodiment, the prepreg pieces 10 and 20 are cut into a fan shape, and the prepreg pieces 10 and 20 are overlapped at regular intervals, and the number of divisions can be arbitrarily set as necessary. It can be set and the degree of freedom of design can be secured.

  Further, in this embodiment, the fiber direction D of the lower layer portion 2 is substantially the circumferential direction, and the fiber direction D of the upper layer portion 3 is substantially the radial direction, as compared with the prior art in which the fiber direction D is only the radial direction. Since sound waves are transmitted in the fiber direction D, the sound can be spread.

  Further, as in the prior art (Patent Document 2), when cutting the carbon prepreg sheet 100 into a trapezoid, compared to the cutting method in which the height direction of the trapezoid is the fiber direction D, in this embodiment, The prepreg piece 20 is cut from the carbon prepreg sheet 100 so that the linear portion 23 of the prepreg piece 20 is substantially parallel to the fiber direction D. For this reason, the cut | interruption of the carbon fiber 101 can be decreased compared with the past, and the loss of acoustic vibration propagation can be avoided.

(Embodiment 2)
The speaker diaphragm according to this embodiment is a cone-shaped diaphragm 1B having a two-layer structure as shown in FIG. In this embodiment, components that are the same as or the same as those in the first embodiment described above are given the same reference numerals. The two-layer structure is composed of a lower layer portion 2 and an upper layer portion 3. Furthermore, the lower layer part 2 is composed of only the first layer 2A (FIG. 6) used in the first embodiment, and the upper layer part 3 is composed of the first layer 3C.

  As shown in FIG. 13, the first layer 3 </ b> C of the upper layer portion 3 is formed by overlapping the edges of the plurality of prepreg pieces 20 with each other. In addition, since several prepreg pieces 20 are used, in order to distinguish each prepreg piece 20, it describes like prepreg pieces 20A and 20B. In the first layer 3C, the straight portion 23A of the prepreg piece 20A is set to be substantially in the radial direction of the cone-shaped diaphragm 1B, and the fiber direction D of the prepreg piece 20A is set to be substantially in the radial direction of the cone-shaped diaphragm 1B. Further, the arc portion 21A of the prepreg piece 20A is used as the circular edge of the cone-shaped diaphragm 1B. The next prepreg piece 20B is arranged next to the prepreg piece 20A thus arranged. At this time, the next prepreg piece 20B is arranged so that the edge portion of the next prepreg piece 20B on the straight line portion 23B side overlaps with the edge portion of the prepreg piece 20A on the straight line portion 24A side. Thus, the prepreg pieces 20 are arranged so that the edge portions of the adjacent linear portions overlap each other, and each arc portion 21 of the prepreg piece 20 forms the entire circumference of the cone-shaped diaphragm 1B, and the prepreg piece 20 is used. The first layer 3C of the upper layer part 3 is formed.

  Like the first embodiment, the lower layer 2 and the upper layer 3 are stacked on the male mold 201 shown in FIG. 9 in the order of the first layer 3C of the upper layer 3 and the first layer 2A of the lower layer 2. Deploy. Thereafter, the female mold 202 is overlaid on the male mold 201, and pressure molding is performed while heating. Thus, the speaker diaphragm 1B using the carbon prepreg sheet 100 is manufactured. Note that, as shown in FIG. 10, a laminated structure using the mount C is preferable because rigidity is improved and ideal acoustic properties are obtained.

  According to this embodiment, substantially the same effect as in the first embodiment can be achieved.

(Embodiment 3)
The speaker diaphragm according to this embodiment is a cone diaphragm 1C having a four-layer structure as shown in FIG. In this embodiment, components that are the same as or the same as those in the first embodiment described above are given the same reference numerals. The four-layer structure is composed of a lower layer portion 2 and an upper layer portion 3. The lower layer part 2 is composed of a first layer 2B and a second layer 2C, and the upper layer part 3 is composed of the first layer 3A used in the first embodiment and the second layer 3B used in the first embodiment. Consists of. In this embodiment, the first layer is the first layer 2B of the lower layer portion 2, the second layer is the second layer 2C of the lower layer portion 2, and the third layer is the first layer 3A of the upper layer portion 3. The fourth layer is the second layer 3B of the upper layer part 3. These are preferably laminated and integrated on the mount C in terms of rigidity and acoustic properties.

  The lower layer part 2 is formed of a plurality of prepreg pieces 10 as shown in FIG. In addition, below, since the several prepreg piece 10 is used, in order to distinguish each prepreg piece 10, it describes like prepreg piece 10A, 10B. That is, the linear portion 13A of the prepreg piece 10A is set to be substantially in the radial direction of the cone-shaped diaphragm 1C, and the fiber direction D of the prepreg piece 10A is set to be substantially in the circumferential direction of the cone-shaped diaphragm 1C. Further, the arc portion 11A of the prepreg piece 10A is used as the circular edge portion of the cone-shaped diaphragm 1C. The next prepreg piece 10B is arranged next to the prepreg piece 10A thus arranged. At this time, the next prepreg piece 10B is arranged so that the straight line portion 13B of the next prepreg piece 10B overlaps the prepreg piece 10A at a position substantially half the center angle A with respect to the arc portion 11A of the prepreg piece 10A. Thus, the prepreg pieces 10 are arranged so that the adjacent prepreg pieces 10B overlap the prepreg pieces 10A, and each arc portion 11 of the prepreg piece 10 forms the entire circumference of the cone-shaped diaphragm 1C. The lower layer part 2 of the used two-layer structure is formed.

  The upper layer portion 3 may be a combination of two layers of FIG. In addition, the lower layer part 2 may also overlap two things of FIG.

  For example, the lower layer 2 and the upper layer 3 are stacked in the order of the upper layer 3 and the lower layer 2 in the male mold 201 shown in FIG. Thereafter, the female mold 202 is overlaid on the male mold 201, and pressure molding is performed while heating. Thus, a speaker diaphragm 1C using the carbon prepreg sheet 100 is manufactured. In addition, as shown in FIG. 10, you may combine with the mount C, In this case, rigidity improves more and an ideal acoustic physical property is obtained.

  This embodiment can achieve substantially the same effect as that of the first embodiment, but the rigidity and the like increase as the number of layers increases.

  The embodiment of the present invention has been described in detail above, but the specific configuration is not limited to each embodiment, and even if there is a design change or the like without departing from the gist of the present invention, Included in the invention. For example, it is possible to freely combine the number of layers using prepreg pieces 10 and 20 having different fiber directions D.

3 is a schematic cross-sectional view of the speaker diaphragm according to Embodiment 1. FIG. 3 is a plan view for explaining cutting of a carbon prepreg sheet according to Embodiment 1. FIG. It is a top view which shows the prepreg piece formed by cutting of a carbon prepreg sheet. 3 is a plan view for explaining cutting of a carbon prepreg sheet according to Embodiment 1. FIG. It is a top view which shows the prepreg piece formed by cutting of a carbon prepreg sheet. It is explanatory drawing explaining arrangement | positioning of each prepreg piece of a lower layer part. It is explanatory drawing explaining arrangement | positioning of each prepreg piece of an upper layer part. The top view of an upper layer part is shown. An example of manufacturing a speaker diaphragm will be described. A preferred example of manufacturing a speaker diaphragm will be described. The frequency characteristic of the speaker using Embodiment 1 is shown. 6 is a schematic cross-sectional view of a speaker diaphragm according to Embodiment 2. FIG. FIG. 6 is an explanatory view for explaining the arrangement of upper layer prepreg pieces according to a second embodiment. 6 is a schematic cross-sectional view of a speaker diaphragm according to Embodiment 3. FIG. FIG. 6 is an explanatory diagram for explaining the arrangement of lower layer prepreg pieces according to a third embodiment. It is a top view explaining a carbon prepreg sheet. It is a top view explaining the conventional cutting method of a carbon prepreg sheet. It is a top view explaining the conventional arrangement | positioning method of a carbon prepreg sheet. It is a top view explaining another conventional cutting method of a carbon prepreg sheet. It is a top view explaining another conventional arrangement method of a carbon prepreg sheet.

Explanation of symbols

1A to 1C Cone-shaped diaphragm 2 Lower layer part (first layer part)
2A, 2B 1st layer 2C 2nd layer 3 Upper layer part (2nd layer part)
3A, 3C first layer 3B second layer 10 prepreg piece (first prepreg piece)
11 circular arc part 12-14 straight part 20 prepreg piece (second prepreg piece)
21 Arc part 22 to 24 Straight part 100 Carbon prepreg sheet 101 Carbon fiber 110 Prepreg strip 201 201 Male mold 202 Female mold A, B Center angle C Mount D Fiber direction

Claims (6)

A first prepreg formed by cutting the carbon prepreg sheet (100) into a fan shape and cutting so that the direction intersecting the radial direction of the fan shape is the fiber direction (D) of the carbon prepreg sheet (100). Speaker vibration formed by the piece (10) and the second prepreg piece (20) formed by cutting the carbon prepreg sheet (100) so that the radial direction is the fiber direction (D). A board,
One or more first prepreg layers are arranged so that the first prepreg pieces (10) overlap with each other and the entire circumference of the diaphragm is formed by the arc portion of each first prepreg piece (10). A laminated first layer portion (2);
The second prepreg pieces (20) are arranged so as to overlap each other, and at least one second prepreg layer forming the entire circumference of the diaphragm is formed by the arc portion of each prepreg piece (20). A speaker diaphragm, comprising: two layer portions (3), wherein the first layer portion (2) is a lower layer and the second layer portion (3) is an upper layer.   The speaker diaphragm according to claim 1, wherein the first and second layer portions (2) and (3) are laminated on a mount (C). The carbon prepreg sheet (100) is cut into a fan shape, and the direction crossing the radial direction of the fan shape is the fiber direction (D) of the carbon prepreg sheet (100), and the first prepreg piece ( 10) and forming the second prepreg piece (20) by cutting the carbon prepreg sheet (100) so that the radial direction is the fiber direction (D),
The first prepreg pieces (10) are arranged so as to overlap each other, and one or more first prepreg layers that form the entire circumference of the diaphragm are formed by arc portions of the prepreg pieces (10). Forming a first layer (2);
One or more second prepreg layers that are arranged so that the second prepreg pieces (20) overlap each other and that form the entire circumference of the diaphragm by the arc portion of each prepreg piece (20) are laminated. Forming a second layer (3),
A method for manufacturing a speaker diaphragm, comprising: laminating the first layer portion (2) as a lower layer and the second layer portion (3) as an upper layer.   4. The method for manufacturing a speaker diaphragm according to claim 3, wherein the first and second layer portions (2) and (3) are laminated on a mount (C). Production method.   4. The speaker diaphragm manufacturing method according to claim 3, wherein the prepreg pieces (20) constituting the second layer portion (3) are laminated so that substantially half of them are stacked. Method for manufacturing a diaphragm for an automobile.   The speaker diaphragm manufacturing method according to claim 3, wherein the prepreg pieces (10) constituting the first layer portion (2) are laminated so that substantially half of the prepreg pieces (10) overlap each other. Method for manufacturing a diaphragm for an automobile.

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