Guitar body structure and guitar

Abstract

Provided is a guitar body structure 2 comprising a body 20 that includes a wooden part 30 composed of rosewood. As viewed from the thickness direction of the body 20, the wood grain direction of the wooden part 30 is inclined with respect to the longitudinal direction of a guitar neck 3.

Description

Guitar body structure and guitar

[0001] The present invention relates to a guitar body structure and a guitar.

[0002] In the past, there have been known techniques for guitar body structures that focus on the grain direction of the wood. For example, in Patent Document 1, the grain direction of the top and back plates is aligned with the longitudinal direction of the resonator body.

[0003] Patent No. 4373854

[0004] In the field of guitars, including electric guitars, the wood that is suitable for use in the body is somewhat limited from the perspective of tone. In the future, if it becomes possible to use wood that has not been used for guitars until now, it will lead to effective use of wood and be useful from the perspective of sustainability.

[0005] If a wood with a higher modulus of elasticity than the wood typically used for guitar bodies were used for the body, the peak frequency would be higher, resulting in a different tone compared to when wood with a lower modulus of elasticity were used. If the wood grain were aligned along the length of the neck as in Patent Document 1, using wood with a high modulus of elasticity for the body would increase the rigidity of the body, potentially making it impossible to achieve the desired tone.

[0006] One object of the present invention is to provide a guitar body structure that can obtain a desired tone even when rosewood is used for the body.

[0007] According to one aspect of the present invention, there is provided a guitar body structure having a body including a wooden portion made of rosewood, wherein, when viewed in the thickness direction of the body, the grain direction of the wooden portion is inclined relative to the longitudinal direction of the guitar neck.

[0008] According to one aspect of the present invention, a desired tone can be obtained even when rosewood is used for the body.

[0009] FIG. 1 is a front view of a guitar to which the body structure according to the first embodiment is applied; FIG. 2 is a front view of the body as viewed from the +Z side; FIG. 3 is a diagram showing acceleration response versus frequency; FIG. 4 is a diagram showing the relationship between acute angles and the rigidity of the body in the longitudinal direction of the neck; FIG. 5 is a front view of the body according to the second embodiment as viewed from the +Z side; FIG. 6 is a front view of the body according to the third embodiment as viewed from the +Z side; FIG. 7 is a schematic cross-sectional view of a wooden part of the first modified example; FIG. 8 is a front view of the body according to the second modified example as viewed from the +Z side;

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] (First embodiment) Fig. 1 is a front view of a guitar to which a body structure according to a first embodiment of the present invention is applied. The guitar 1 is, as an example, an electric guitar. The guitar 1 comprises a body structure 2, a neck 3, and strings 4. The body structure 2 comprises a body 20 including a wood portion 30 (see Fig. 2) made of wood. In this embodiment, the body 20 constitutes the entire body structure 2. The body 20 is formed in a plate shape.

[0012] In the following description, the longitudinal direction of the neck 3, among directions perpendicular to the thickness direction (Z direction) of the body 20, is referred to as the longitudinal direction (Y direction) of the body 20. The direction perpendicular to the thickness direction and longitudinal direction of the body 20 is referred to as the width direction (X direction) of the body 20.

[0013] The neck 3 is connected to an end of the body structure 2 and extends in a direction (+Y direction) away from the body structure 2. A head 5, which forms the distal end of the neck 3 in the longitudinal direction, is provided with a peg 6 around which the end of a string 4 is wound. The string 4 is stretched along the longitudinal direction of the neck 3.

[0014] The bridge 7, electromagnetic pickup 8, controller, etc. are attached to the body 20. The bridge 7, electromagnetic pickup 8, and controller are exposed on the front surface 20a, which is the surface on the +Z side in the thickness direction of the body 20.

[0015] One end of the string 4 is fastened to the bridge 7. The electromagnetic pickup 8 is located between the neck 3 and the bridge 7 in the longitudinal direction of the neck 3. Multiple electromagnetic pickups 8 (two in the illustrated example) are lined up in the longitudinal direction of the neck 3. The controller adjusts the volume, tone, etc. of the acoustic signal output from the electromagnetic pickups 8. The controller includes two volume switches 9 and a pickup selector 10 that switches which electromagnetic pickup 8 is activated.

[0016] In this embodiment, the wood portion 30 included in the body 20 is made of rosewood (Fabaceae, Dalbergia genus). Rosewood has a higher elastic modulus than woods commonly used for electric guitar bodies (such as hard maple, which has an elastic modulus of approximately 10 to 14 GPa). A higher elastic modulus increases the rigidity of the body 20, which in turn increases the peak frequency, potentially making it difficult to achieve the desired tone.

[0017] Therefore, in this embodiment, rosewood, a wood with a relatively high elastic modulus, is used for the wooden portion 30, while the rigidity of the body 20 is reduced by adjusting the grain direction of the wooden portion, as described below. The rosewood that can be used for the wooden portion 30 may be any of Indian rosewood, Madagascar rosewood, Honduran rosewood, Jacaranda (Brazilian rosewood, commonly known as Jacaranda), Sonokelin, and Guatemalan rosewood, or a combination of two or more of these. In this embodiment, the wooden portion 30 included in the body 20 may be formed by stacking multiple pieces of wood in the Z direction, or may be formed from a single piece of wood.

[0018] 2 is a front view of the body 20 as viewed from the +Z side. The center line A1 is an imaginary straight line that passes through the center of the body 20 in the width direction (X direction) and extends in the longitudinal direction (Y direction) of the neck 3.

[0019] The wood portion 30 of the body 20 has multiple wood grains 22. The extension directions of the multiple wood grains 22 are generally parallel to each other when viewed from the Z direction (hereinafter, referred to as the thickness direction of the body 20). The extension direction of the wood grains 22 when viewed from the Z direction is referred to as the wood grain direction. The wood grain direction is a concept obtained by averaging the extension directions of the multiple wood grains 22. A virtual straight line parallel to the wood grain direction when viewed from the Z direction is referred to as line L1. The wood grain direction may also be defined as the same direction as the fiber direction of the wood that constitutes the wood portion 30.

[0020] A pickguard 21 is provided on the body 20. The pickguard 21 is disposed on the +Z side of the wooden portion 30. A virtual straight line parallel to the extension direction of one side 21a of the pickguard 21 when viewed from the Z direction is defined as a straight line L2.

[0021] 2, the grain direction of the wood portion 30 is inclined with respect to the longitudinal direction of the neck 3 when viewed from the Z direction. That is, when viewed from the Z direction, the center line A1, which is parallel to the longitudinal direction of the neck 3, and the line L1 are not parallel. The lines L1 and L2 are parallel.

[0022] When viewed from the Z direction, the acute angle formed by the center line A1 and the grain direction is defined as acute angle θ. In the example shown in Fig. 2, the acute angle θ formed by the center line A1 and the grain direction on the neck 3 side (+Y side) in the longitudinal direction of the neck 3 is set to 60°. The acute angle formed by the center line A1 and the grain direction on the opposite side of the neck 3 (-Y side) in the longitudinal direction of the neck 3 is also the same as acute angle θ. The effect of tilting the grain direction with respect to the center line A1 will be explained using Fig. 3.

[0023] 3 is a graph showing the acceleration response (dB / N) versus frequency (Hz). The acceleration response corresponds to the vibration level. In FIG. 3, three combinations of wood and grain direction used for the wood part 30 are shown.

[0024] The acceleration response is obtained as follows: the worker vibrates the head 5, detects vibrations at multiple locations near the outer periphery of the body 20, and averages the detected values. The worker repeats this process multiple times by changing the vibration value of the head 5, and for each combination of wood and wood grain direction. This process allows the acceleration response corresponding to the frequency to be obtained for each combination of wood and wood grain direction (first to third examples).

[0025] The first example uses wood that is commonly used in guitars (e.g., maple or mahogany), and the grain direction is parallel to the center line A1 (acute angle θ=0°), and curve 31 corresponds to this.

[0026] The second example is an example in which Honduras rosewood is used and the grain direction is parallel to the center line A1 (acute angle θ=0°), and curve 32 corresponds to this.

[0027] The third example is an example in which Honduras rosewood is used and the grain direction is inclined by 60° with respect to the center line A1 (acute angle θ=60°), and curve 33 corresponds to this.

[0028] Among the peaks of the acceleration response, peaks P1 to P3 and P11 to P13 will be used as examples. Peaks P1, P2, and P3 are the peaks in the first, second, and third examples, respectively. Peaks P11, P12, and P13 are also the peaks in the first, second, and third examples, respectively.

[0029] The frequencies at which peaks P2 and P12 occur are higher in the second example than the frequencies at which peaks P1 and P11 occur in the first example. In other words, the peak frequencies in the second example are shifted higher compared to the first example. This is because the stiffness of the body 20 is increased due to the higher elastic modulus of the wood used.

[0030] The frequencies at which peaks P3 and P13 occur in the third example are lower than the frequencies at which peaks P2 and P12 occur in the second example, and are closer to the frequencies at which peaks P1 and P11 occur in the first example. This is because the increased rigidity resulting from the higher elastic modulus of the wood used is offset by the inclination of the wood grain direction by 60 degrees relative to the center line A1. In other words, the inclination of the wood grain direction reduces the rigidity of the body 20. As a result, the rigidity of the body 20 in the third example is similar to that of the first example, allowing for the desired tone color to be achieved despite the use of wood with a high elastic modulus.

[0031] The stiffness of the body 20 that contributes to the tone color is primarily the bending stiffness of the body 20 in the longitudinal direction of the neck 3, which corresponds to the stiffness against bending around the X-axis. However, the stiffness that is subject to change by varying the inclination of the grain direction may include bending stiffness in other directions in addition to tension and compression.

[0032] From the viewpoint of reducing the rigidity of the body 20 by tilting the grain direction, the acute angle θ is not limited to 60°, but may be any angle greater than 0°, and is preferably 30° or more and 70° or less.

[0033] 4 is a diagram showing the relationship between the acute angle θ and the rigidity of the body 20 in the longitudinal direction of the neck 3. This diagram shows the percentage decrease in rigidity when the acute angle θ is changed from 0° to 90°, with the case where the grain direction is parallel to the center line A1 (acute angle θ = 0°) set as the reference (100%).

[0034] A typical characteristic of wood is that the modulus of elasticity in the direction perpendicular to the grain (the direction of the fibers, the direction of the straight line L1) is reduced to approximately 1 / 10. Therefore, for example, when the acute angle θ is 90°, the rigidity is 10%, which is approximately 1 / 10 of the rigidity when the acute angle θ is 0°. When the acute angle θ is between 30° and 70°, the rigidity falls within the range of R2 to R1 (R1<R2). R2 to R1 is a suitable range for the rigidity of the body 20 after reduction, and is approximately 92% to 43%.

[0035] Furthermore, from the perspective of achieving the effects of the present invention, the rosewood suitable for use in the wooden portion 30 should have a modulus of elasticity of 17 GPa or more, preferably 20 GPa or more. Wood with a modulus of elasticity of 17 GPa or more is generally considered too high for guitars and is not typically used. It is more preferable that the rosewood suitable for use in the wooden portion 30 has a modulus of elasticity higher than that of Indian rosewood. In this case, the average values ​​of the modulus of elasticity, which are understood as physical properties of wood, are compared. For example, Honduras rosewood generally satisfies the conditions of "a modulus of elasticity of 20 GPa or more" and "having a modulus of elasticity higher than that of Indian rosewood."

[0036] Furthermore, the rosewood used for the wooden portion 30 may be waste wood that was unused during the manufacturing of other musical instruments. For example, rosewood with high rigidity is generally used for marimbas. Honduras rosewood is an example of a highly rigid rosewood. Reusing parts that would not have been used during the manufacturing process of marimba sound plates not only reduces costs but also contributes to improving sustainability.

[0037] Furthermore, from the perspective of improving the appearance, the extension direction of at least one side of the pickguard 21 is aligned with the grain direction when viewed from the Z direction. As shown in Figure 2, when viewed from the Z direction, a line L2 parallel to the side 21a of the pickguard 21 is parallel to a line L1 indicating the grain direction, so that the side 21a and the grain direction are aligned when viewed from the Z direction, resulting in a good appearance. Note that, depending on the shape of the pickguard 21, the side of the pickguard 21 that is parallel to the grain direction is not limited to the side 21a, and may be another side.

[0038] According to this embodiment, the grain direction of the wooden portion 30 is inclined relative to the longitudinal direction of the guitar neck 3 when viewed from the thickness direction of the body 20, so that the desired tone can be obtained even if rosewood is used for the body 20.

[0039] It is sufficient that the grain direction of at least a portion of the wood portion 30 used in the body 20 is inclined relative to the longitudinal direction of the neck 3 .

[0040] It is not essential that the extension direction of at least one side of the pickguard 21 coincide with the grain direction. Also, it is not essential to provide the pickguard 21.

[0041] It is sufficient that the center line A1 and the grain direction form an acute angle θ when viewed from the Z direction. Therefore, the inclination of the grain direction in the Y direction may be reversed from that shown in the example. For example, in this embodiment, the acute angle θ is an acute angle occurring on both the +Y side and the +X side, but the acute angle θ may also be an acute angle occurring on both the +Y side and the -X side.

[0042] Second Embodiment A second embodiment of the present invention differs from the first embodiment mainly in the setting of the wood grain direction, but the rest of the configuration is the same.

[0043] 5 is a front view of the body 20 of this embodiment as viewed from the +Z side. The body 20 has two convex portions (a first convex portion 24 and a second convex portion 25). The first convex portion 24 and the second convex portion 25 have different shapes, and the first convex portion 24 protrudes more toward the +Y side than the second convex portion 25. Therefore, the body 20 is formed asymmetrically with respect to the center line A1. The imaginary line LB is an extension of the line segment at which the length of the body 20 (the distance between two points on the circumferential edge) is longest when viewed in the Z direction.

[0044] In this embodiment, the grain direction is parallel to the line LB when viewed from the Z direction, i.e., extends in the direction in which the length of the body 20 is longest when viewed from the Z direction. That is, the line L1 indicating the grain direction is parallel to the line LB. The acute angle θ formed between the center line A1 and the grain direction on the neck 3 side (and the opposite side from the neck 3) in the longitudinal direction of the neck 3 is slightly larger than 30°.

[0045] If there were no inclination in the grain direction (acute angle θ = 0°), the vibration displacement in the first convex portion 24, which has a longer protrusion length, would be larger than the vibration displacement in the second convex portion 25. However, since line L1 is parallel to line LB, vibration in the first convex portion 24 is suppressed compared to the second convex portion 25. Therefore, it is possible to suppress large vibrations in only one portion of the body 20, and to allow the entire body 20 to vibrate in a balanced manner.

[0046] In this embodiment, the wood part 30 is formed by joining a plurality of wooden pieces 26. When viewed from the Z direction, a virtual line parallel to the extension direction of the joining surfaces 23 between adjacent wooden pieces 26 is defined as line L3. When viewed from the Z direction, line L3 coincides with the grain direction. By aligning the two, the grain direction and the longitudinal direction of the wooden pieces 26 are aligned, improving the appearance.

[0047] According to this embodiment, by tilting the grain direction, it is possible to obtain the desired tone color even when using rosewood for the body 20, with the same effect as in the first embodiment.

[0048] Furthermore, in the body 20, which is asymmetrical with respect to the center line A1, the grain direction extends in the direction in which the length of the body 20 is longest when viewed from the thickness direction, so that the peak frequency can be lowered and the entire body can be vibrated in a balanced manner to obtain the desired tone.

[0049] Furthermore, when viewed from the Z direction, the direction of the joint surface 23 coincides with the grain direction, so the grain direction and the longitudinal direction of the wood 26 are aligned, improving the appearance.

[0050] It is not necessary to have both a configuration in which the grain direction (straight line L1) and the line LB are parallel, and a configuration in which the grain direction (straight line L1) and the line L3 are parallel; only one of these may be provided.

[0051] For example, in a configuration in which the wooden part 30 has a joint surface 23, the wood grain direction may not be parallel to the line LB, and the wood grain direction may be parallel to the line L3. Alternatively, the wood grain direction may be parallel to the line LB, and the wood grain direction may not be parallel to the line L3. Furthermore, in a configuration in which the wooden part 30 does not have a joint surface 23, the wood grain direction may be parallel to the line LB.

[0052] Any of these configurations regarding the grain direction may also be applied when the pickguard 21 is provided. In this case, as in the first embodiment, a configuration may be adopted in which the extension direction of at least one side of the pickguard 21 coincides with the grain direction.

[0053] In the first embodiment, the wooden part 30 may have a joint surface 23. In this case, the first embodiment may have the grain direction and the direction of the joint surface 23 coincide with each other.

[0054] Third Embodiment A third embodiment of the present invention differs from the first embodiment mainly in the configuration of the wood portion and the setting of the grain direction, but the other configurations are the same.

[0055] 6 is a front view of the body 20 of this embodiment as seen from the +Z side. In this embodiment, the wooden parts included in the body 20 include a first wooden part 30-1 and a second wooden part 30-2. As an example, the first wooden part 30-1 and the second wooden part 30-2 belong to the areas on the -X side and the +X side, respectively, of the center line A1.

[0056] The grain direction of the first wood part 30-1 is parallel to the line L1-1. The grain direction of the second wood part 30-2 is parallel to the line L1-2. When viewed from the Z direction, the grain direction of the first wood part 30-1 (line L1-1) and the grain direction of the second wood part 30-2 (line L1-2) are symmetrical with respect to the center line A1.

[0057] The center line A1 and the straight line L1-1 form an acute angle θ-1 on the neck 3 side (and the opposite side from the neck 3) in the longitudinal direction of the neck 3. The center line A1 and the straight line L1-2 form an acute angle θ-2 on the neck 3 side (and the opposite side from the neck 3) in the longitudinal direction of the neck 3. The magnitude of the acute angle θ-1 and the magnitude of the acute angle θ-2 are the same. The significance of the acute angles θ-1 and θ-2 is the same as that of the acute angle θ in the first embodiment, and their magnitude is, for example, 60°. The straight lines L2 and L1-2 are parallel to each other.

[0058] Even with such a grain direction setting, the effect of reducing the rigidity of the body 20 in the longitudinal direction of the neck 3 is the same as in the first embodiment.

[0059] According to this embodiment, by tilting the grain direction, it is possible to obtain the desired tone color even when using rosewood for the body 20, with the same effect as in the first embodiment.

[0060] In this embodiment, the inclination direction of the wood grain 22 of each of the first wood portion 30-1 and the second wood portion 30-2 in the Y direction may be reversed from that shown in Fig. 6. That is, in the example of Fig. 6, the wood grain shape when viewed from the Z direction with the +Y direction facing up is V-shaped, but it may also be an inverted V-shape. In this case, the acute angle formed by the longitudinal direction of the neck 3 and the wood grain direction on the opposite side of the neck 3 in the longitudinal direction of the neck 3 (the -Y side) when viewed from the Z direction may be 30° to 70°, preferably 60°.

[0061] In this embodiment, either or both of the first wood part 30-1 and the second wood part 30-2 may be formed by joining a plurality of pieces of wood 26 as shown in the second embodiment. In this case, the grain direction of the first wood part 30-1 may coincide with the extension direction of the joining surface 23 of the first wood part 30-1. The grain direction of the second wood part 30-2 may coincide with the extension direction of the joining surface 23 of the second wood part 30-2.

[0062] It is not essential that the extension direction of at least one side of the pickguard 21 coincide with the grain direction. Also, it is not essential to provide the pickguard 21.

[0063] In each of the above embodiments, the wood part 30 (or the first wood part 30-1 or the second wood part 30-2) may be configured by laminating multiple wood layers as shown in Fig. 7. A first modified example will be described using the wood part 30 as an example.

[0064] Figure 7 is a schematic cross-sectional view of a wood section 30 of a first modified example. The wood section 30 is formed by laminating a first wood layer 27 and a second wood layer 28. The first wood layer 27 and the second wood layer 28 may have the same thickness, but in the example shown in Figure 7, they have different thicknesses. Although not shown, when viewed from the Z direction, the grain direction of at least one of the first wood layer 27 and the second wood layer 28 is inclined with respect to the longitudinal direction of the neck 3. The grain direction of the second wood layer 28 is different from the grain direction of the first wood layer 27.

[0065] In this way, by stacking wood layers of different thicknesses and making the grain directions of the two wood layers different from each other, it becomes easy to obtain the desired rigidity, which makes it easy to fine-tune the peak frequency.

[0066] It does not matter whether the wood layer on the top side (+Z side) or the wood layer on the back side (-Z side) is thicker. The number of laminated wood layers may be three or more. The grain direction of at least one of the laminated wood layers may be inclined with respect to the longitudinal direction of the neck 3. The grain direction of at least one of the laminated wood layers may be different from the grain direction of at least one of the other layers.

[0067] In each of the above embodiments, the body 20 may be, for example, a solid body without an internal chamber (cavity) for reducing weight, or may be a semi-solid body with an internal chamber as shown in Fig. 8. A second modification will now be described.

[0068] Figure 8 is a front view of the body 20 of the second modified example, viewed from the +Z side. The wood grain 22 is not shown in Figure 8. The body 20 is provided with one or more chambers 29. The provision of the chambers 29 has the effect of reducing the rigidity of the body 20. Therefore, when using rosewood, which has a high elastic modulus, the inclination of the wood grain 22 and the reduction in rigidity due to the chambers 29 can be expected, making it easier to obtain the desired tone.

[0069] The present invention is not limited to electric guitars, but is also suitable for electric basses, and application to acoustic guitars is not excluded.

[0070] When rosewood is used, the thickness of the body 20 may be thinner than when other woods having a lower elastic modulus than rosewood are used.

[0071] While the present invention has been described in detail above based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the gist of the present invention are also included in the present invention. Parts of the above-described embodiments may be combined as appropriate.

[0072] 2 body structure, 3 neck, 20 body, 21 pickguard, 22 wood grain, 30, 30-1, 30-2 wood part, L1, L1-1, L1-2, L2, L3 straight line, A1 center line

Claims

1. A guitar body structure comprising a body including a wooden portion made of rosewood, wherein, when viewed in the thickness direction of the body, the grain direction of the wooden portion is inclined with respect to the longitudinal direction of the guitar neck.

2. The guitar body structure of claim 1, wherein the rosewood is any one of Indian rosewood, Madagascar rosewood, Honduran rosewood, Jacaranda, Sonokelin, or Guatemalan rosewood, or a combination of two or more thereof.

3. The guitar body structure according to claim 1, wherein the acute angle between the longitudinal direction and the grain direction when viewed from the thickness direction is greater than or equal to 30° and less than or equal to 70°.

4. The guitar body structure of claim 1, wherein the rosewood is a wood having an elastic modulus of 17 Gpa or more.

5. The guitar body structure of claim 1, wherein the rosewood is a wood having a higher elastic modulus than that of Indian rosewood.

6. The guitar body structure of claim 1, wherein the body is formed in an asymmetric shape with respect to a line that passes through the center in the width direction of the body and extends in the longitudinal direction, and the grain direction extends in the direction in which the length of the body is longest when viewed from the thickness direction.

7. A guitar body structure as described in claim 1, wherein the wood portion is constructed by laminating a first wood layer and a second wood layer having different thicknesses, and when viewed from the thickness direction, the grain direction of the first wood layer is inclined with respect to the longitudinal direction, and the grain direction of the second wood layer is different from the grain direction of the first wood layer.

8. The guitar body structure according to claim 1, wherein the wooden portion is constructed by joining a plurality of pieces of wood together, and when viewed in the thickness direction, the direction of the joint surfaces of the plurality of pieces of wood coincides with the grain direction.

9. The guitar body structure according to claim 1, wherein the body has a pickguard, and when viewed in the thickness direction, the extension direction of at least one side of the pickguard coincides with the grain direction.

10. The guitar body structure of claim 9, wherein the wooden portion is formed by joining multiple pieces of wood together, and when viewed in the thickness direction, the direction of the joint surfaces of the multiple pieces of wood coincides with the extension direction of at least one side of the pickguard.

11. A guitar body structure as described in claim 1, wherein the wood portion includes a first wood portion and a second wood portion, and when viewed in the thickness direction, the grain direction of the first wood portion and the grain direction of the second wood portion are symmetrical with respect to a straight line that passes through the center of the width of the body and extends in the longitudinal direction.

12. The guitar body structure of claim 1, wherein the grain direction of the wood portion is the fiber direction of the wood portion.

13. The guitar body structure of claim 1, wherein the guitar is an electric guitar.

14. A guitar comprising a guitar body structure according to any one of claims 1 to 13.

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