Key for keyboard device

Abstract

To improve bonding strength of a key that is made by bonding wood and resin materials.SOLUTION: A key for a keyboard device comprises: a wooden key body; a resin-made key upper surface portion provided on the upper surface of the key body; an adhesive for bonding the key body and the key upper surface portion. And a recess is formed on the lower surface of the key upper surface portion, and recess and convex shapes are formed in the interior of the recess. A diameter of the recess is 20 μm or more and 500 μm or less, and a height difference of at least part of the recess and convex shapes may be 20 μm or more.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] One embodiment of the present invention relates to a key for a keyboard device.

Background Art

[0002] Generally, in keyboard devices such as acoustic pianos and electronic pianos, keys in which a resin material is attached to the upper surface of a wooden key body or keys in which wood is attached to the side portion of a resin key body are used (Patent Documents 1 and 2). If the attached resin material and wood peel off, not only the appearance of the piano is impaired, but it may also hinder the performance of the user (performer). Therefore, it is necessary to prevent the peeling of wood and the resin material.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, due to environmental considerations, when bonding wood and a resin material, there has been a need to use a water-soluble adhesive (e.g., woodworking bond) instead of an organic solvent-based (polyurethane-based) adhesive. However, the surface of the resin material is very flat, and the woodworking bond does not penetrate into the resin material, so sufficient adhesive strength cannot be obtained. As a result, interfacial failure occurs between the resin material and the adhesive, and there has been a problem that the resin material peels off from the wood. Conventionally, in order to improve the adhesive strength between the woodworking bond and the resin material, measures such as sanding the surface of the resin material or creating a textured surface using a mold have been taken, but sufficient adhesive strength has not been obtained.

[0005] One of the objectives of an embodiment of the present invention is to improve the adhesion strength between wood and a resin material in a key for bonding them.

Means for Solving the Problem

[0006] The key for a keyboard device according to an embodiment of the present invention has a key body portion made of wood, a key upper surface portion made of resin provided on the upper surface of the key body portion, and an adhesive for bonding the key body portion and the key upper surface portion. A concave portion is provided on the lower surface of the key upper surface portion, and an uneven shape is further formed inside the concave portion.

[0007] The diameter of the concave portion is 20 μm or more and 500 μm or less, and the height difference of at least a part of the uneven shape may be 20 μm or more.

[0008] On the lower surface of the key upper surface portion, there may be a first portion that can be visually recognized when viewed from the key body portion, and a second portion that is located in the shadow of the first portion and cannot be visually recognized when viewed from the key body portion.

[0009] The key for a keyboard device according to an embodiment of the present invention has a key body portion made of wood, a key upper surface portion made of resin provided on the upper surface of the key body portion, and an adhesive for bonding the key body portion and the key upper surface portion. On the lower surface of the key upper surface portion, there are a first portion that can be visually recognized when viewed from the key body portion, and a second portion that is located in the shadow of the first portion and cannot be visually recognized when viewed from the key body portion.

[0010] A concave portion may be provided on the lower surface of the key upper surface portion, and the uneven shape may be formed inside the concave portion.

[0011] The adhesive may be a water-soluble adhesive.

[0012] A plurality of the concave portions may be provided, and the plurality of concave portions may be arranged periodically in a plan view.

[0013] The concavo-convex shape is provided on a part of the lower surface of the key upper surface portion, and the lower surface of the key upper surface portion in other parts may be flat.

[0014] The concavo-convex shape may be provided on the lower surface of the key upper surface portion corresponding to a region 3 mm or more from the tip of the key body portion.

[0015] The first region at the tip of the lower surface of the key upper surface portion protrudes from the tip of the key body portion, and the concavo-convex shape may not be formed on the lower surface of the key upper surface portion in the first region.

Effect of the Invention

[0016] According to an embodiment of the present invention, in a key for bonding wood and a resin material, the bonding strength between the two can be improved.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

[0018] Hereinafter, the key for a keyboard device in one embodiment of the present invention will be described in detail with reference to the drawings. The following embodiments are examples of the embodiments for carrying out the present invention, and the present invention is not construed as being limited to these embodiments. In the drawings referred to in this embodiment, the same parts or parts having the same function are denoted by the same reference numerals or similar reference numerals, and repeated descriptions thereof may be omitted. The dimensional ratios in the drawings (the ratios between the respective components, the ratios in the vertical, horizontal, and height directions, etc.) may be different from the actual ratios for convenience of explanation, and a part of the configuration may be omitted from the drawings. In the following description, based on the vertical direction in each drawing, there may be expressions such as "upper", "above", "upper end", "lower", "below", "lower end", but these vertical directions only explain the relative directional relationship and may be reversed.

[0019] [1. Overall Configuration of Keyboard Device 10] FIG. 1 is a perspective view showing the appearance of a keyboard device 10 in one embodiment of the present invention. The keyboard device 10 has a keyboard on which a plurality of keys 100 are arranged and a pedal 200. The keys 100 and the pedal 200 are provided on the front surface of the keyboard device 10. A performance is performed by a performer operating the keys 100 and the pedal 200. In FIG. 1, a grand piano is shown as an example of the keyboard device 10, but the keyboard device 10 according to this embodiment is not limited to a grand piano and may be an upright piano or an electronic piano. Although there are a plurality of pedals for the keyboard device 10, the pedal 200 indicates a damper pedal.

[0020] FIG. 2 is a side view showing the action mechanism of the keyboard device in one embodiment of the present invention. In FIG. 2, among a plurality of keys 100 provided in the keyboard device 10, the configuration of one white key 100 is illustrated. Since the other white keys and black keys have the same configuration as that in FIG. 2, the description thereof is omitted. As shown in FIG. 2, the keyboard device 10 includes a white key 100, an action mechanism 300, a hammer 400, a string 500, a damper 600, and a damper operation mechanism 700.

[0021] The action mechanism 300 and the hammer 400 are provided corresponding to each white key 100. When the white key 100 is pressed, a force is transmitted through the action mechanism 300, and the hammer 400 moves to strike the string 500 provided corresponding to the white key 100. The string 500 is a sounding body that produces sound when struck by the hammer 400. When the string 500 is struck, the string 500 vibrates at a vibration frequency corresponding to each white key 100. The damper 600 is moved by the damper operation mechanism 700. The damper operation mechanism 700 controls the contact state or non-contact state between the damper 600 and the string 500 according to the depression amount of the white key 100 and the depression amount of the pedal 200. When the damper 600 comes into contact with the string 500, the vibration of the string 500 stops and the sound production stops.

[0022] In addition to the above members, the keyboard device 10 is provided with a stopper 800, a key sensor 810, and a hammer sensor 820. The stopper 800 is a member that collides with the hammer shank and restricts the upward rotation of the hammer 400. The key sensor 810 is provided at the lower part of the white key 100 and outputs a detection signal corresponding to the behavior of the white key 100 to the control device. For example, the key sensor 810 detects the depression amount of the white key 100 as a continuous amount (fine resolution) and outputs a detection signal indicating the detection result to the control device. The hammer sensor 820 is provided corresponding to each hammer 400 and outputs a detection signal corresponding to the behavior of the hammer 400 to the control device. For example, the hammer sensor 820 detects the moving speed of the hammer 400 immediately before hitting the string 500 and outputs a detection signal indicating the detection result to the control device. Based on the detection signals from the key sensor 810 and the hammer sensor 820, the control device specifies the hitting timing (key-on timing) and hitting speed (velocity) of the hammer 400 with respect to the string 500 corresponding to each white key 100 (key number).

[0023] [2. Structure of Keys] FIG. 3 is a side view of a key and an enlarged view of a part thereof in an embodiment of the present invention. As shown in FIG. 3, the white key 100 has a key body portion 110, a key upper surface portion 120, and a key front surface portion 130. The key body portion 110 is made of wood, and the key upper surface portion 120 and the key front surface portion 130 are made of a resin material. The key upper surface portion 120 is provided on the upper surface of the key body portion 110. The key front surface portion 130 is provided on the front surface (end face in the D1 direction) of the key body portion 110. The key upper surface portion 120 and the key front surface portion 130 are adhered to the key body portion 110 using a water-soluble adhesive such as a vinyl acetate resin-based emulsion adhesive (woodworking bond), for example.

[0024] The thickness of the upper key surface 120 and the front key surface 130 is 1 mm or more and 3 mm or less, or 1.5 mm or more and 2.0 mm or less. Therefore, there are limitations on the method of applying uneven processing to the upper key surface 120 and the front key surface 130. For example, as the upper key surface 120 and the front key surface 130, acrylic resin (PMMA resin), ABS resin, AS resin, and unsaturated polyester resin are used. The upper key surface 120 and the front key surface 130 may be the same member or different members. For example, PMMA resin may be used as the upper key surface 120 and ABS resin may be used as the front key surface 130.

[0025] The upper key surface 120 protrudes in the D1 direction beyond the front end (the end in the D1 direction) of the key body 110 and protrudes more in the D1 direction than the front key surface 130. The protruding portion may be referred to as the protruding portion TP. The amount by which the protruding portion TP protrudes from the front surface (the surface on the D1 direction side) of the front key surface 130 is 1 mm or more and 5 mm or less, or 1.5 mm or more and 3 mm or less.

[0026] As shown in the partial enlarged view (A) of FIG. 3, an adhesive layer 150 is provided between the key body 110 and the upper key surface 120. The adhesive layer 150 is in contact with the lower surface of the upper key surface 120. The adhesive layer 150 is a water-soluble adhesive. For example, as the adhesive layer 150, the wood bond as described above is used. The wood bond is a water-soluble adhesive containing vinyl acetate resin as a component. The wood bond solidifies when the moisture contained in the wood bond is absorbed or evaporated by the wood. Wood is porous and a very complex uneven shape is formed on its surface. When a water-soluble adhesive is used for bonding wood, the water-soluble adhesive solidifies while entering the uneven shape of the wood. Therefore, the water-soluble adhesive provides a strong adhesive force to the wood. On the other hand, since the surface of the resin material is flat, the water-soluble adhesive cannot enter its interior. Therefore, the water-soluble adhesive cannot provide a strong adhesive force to the resin material.

[0027] Figure 4 is a partially enlarged view of the dotted-line frame (B) in Figure 3. As shown in Figure 4, a plurality of recesses 121 are provided on the lower surface of the key upper surface portion 120. The width W of the recess 121 is 20 μm or more and 500 μm or less, 50 μm or more and 300 μm or less, 50 μm or more and 200 μm or less, or 75 μm or more and 150 μm or less. The depth of the recess 121 is 20 μm or more, 30 μm or more, or 40 μm or more. The recesses 121 are provided periodically at intervals P0. The periodicity of the recesses 121 can be evaluated by performing Gaussian fitting on the shape of the recesses 121 and measuring the distance between the vertices of the profile after fitting. Inside the recess 121, an uneven shape is further formed. Details of the uneven shape will be described later.

[0028] Although details will be described later, among the lower surfaces of the key upper surface portion 120, the regions where the recesses 121 are not provided (regions sufficiently separated from the recesses 121) are flat. The depth of the above-described recess 121 is the depth based on the flat surface among the lower surfaces of the key upper surface portion 120. In Figure 4, between adjacent recesses 121, it may have a shape that protrudes downward when forming the recess 121. Therefore, when evaluating the depth of the recess 121, it is evaluated based on the flat lower surface of the key upper surface portion 120 as described above.

[0029] Figure 5 is a partially enlarged view of the dotted-line frame (C) in Figure 4. The enlarged view shown in Figure 5 is an enlarged view of a part of the recess 121 in Figure 4. In Figure 4, for convenience of explanation, the inside of the recess 121 is shown with small steps, but actually, as shown in Figure 5, a large-step uneven shape 122 is formed inside the recess 121. For example, the height difference PV of at least a part of the uneven shape 122 is 20 μm or more. As shown in Figure 5, the uneven shape 122 formed inside the recess 121 is not periodic like the recess 121 and is arranged irregularly.

[0030] In the partial enlarged view (D) of FIG. 5, one concave shape 123 and one convex shape 124 of the concavo-convex shape 122 are enlarged and shown. As shown in FIG. 5, an undercut shape is formed by the concave shape 123 and the convex shape 124. That is, on the key upper surface portion 120 in the concave shape 123, when viewed from below (when viewed from the side of the key body portion 110), there are a visible region R1 and an invisible region R2. By having such a shape, even when an external force in a direction away from the key upper surface portion 120 is applied to the adhesive layer 150, the adhesive layer 150 formed in the region R2 is locked by the convex shape 124, so that the adhesive layer 150 is prevented from peeling off from the key upper surface portion 120. That is, the adhesive layer 150 is firmly adhered to the key upper surface portion 120 by the anchor effect of the undercut shape. In the key upper surface portion 120, the portion in the region R1 may be referred to as the "first portion", and the portion in the region R2 may be referred to as the "second portion".

[0031] On the lower surface of the key upper surface portion 120, a plurality of undercut shapes similar to the above-described concave shape 123 and convex shape 124 are provided. Since the anchor effect is exerted by each of the plurality of undercut shapes, the adhesive strength between the adhesive layer 150 and the key upper surface portion 120 can be improved.

[0032] [3. Method for Forming the Recess 121 and the Concavo-Convex Shape 122] The formation of the recess 121 and the concavo-convex shape 122 shown in FIGS. 4 and 5 is realized by performing laser irradiation on the lower surface of the key upper surface portion 120 with a low output. The output of the laser beam used for the laser irradiation is, for example, 1 W or more and 100 W or less, 5 W or more and 50 W or less, or 10 W or more and 20 W or less. As the laser irradiation device, a device that irradiates laser light continuously may be used, or a device that irradiates laser light periodically may be used. When a laser irradiation device that irradiates laser light periodically is used, for example, the laser light may be irradiated at a period corresponding to a frequency of 10 kHz or more and 50 kHz or less, or 20 kHz or more and 30 kHz or less. The scanning speed of the laser beam in this case is 500 mm / sec or more and 3000 mm / sec or less, 1000 mm / sec or more and 2200 mm / sec or less.

[0033] For example, in a laser irradiation device for processing metal, the output of the laser light is greater than 100 W. However, when using such a high-output laser device to process a resin material such as the key top surface portion 120, the resin in the region irradiated with the laser light will completely melt or carbonize, so an undercut shape as shown in FIG. 5 cannot be obtained. Therefore, in the present embodiment, in order to obtain an undercut shape, the key top surface portion 120 is irradiated with laser light at the output within the above numerical range. As such a laser irradiation device, a laser marker device can be used. Since the laser marker device only cuts or melts the outermost layer of the member to be processed, it irradiates the laser light with a very weak output compared to the laser irradiation device for processing.

[0034] In the conventional filing and texturing processes, only a concave shape with a tapered shape can be formed, so an undercut shape as shown in FIG. 5 cannot be obtained. Also, as described above, with the laser irradiation device for processing, even if the output of the laser light is reduced, the undercut shape cannot be obtained. However, by using a laser marker device with an output smaller than that of the laser irradiation device for processing and only processing the outermost layer of the object, an undercut shape can be formed on the lower surface of the key top surface portion 120 as described above. By forming this undercut shape, the adhesive strength between the key top surface portion 120 and the adhesive layer 150 can be improved.

[0035] [4. Undercut formation region 125] FIG. 6 is a diagram showing the laser irradiation location of the upper surface material of the key in an embodiment of the present invention. As shown in FIG. 6, an undercut formation region 125 is provided near the tip 126 in the D1 direction of the key top surface portion 120. In the undercut formation region 125, the concave portion 121 and the undercut shape 122 shown in FIGS. 4 and 5 are provided. The undercut formation region 125 is provided only in the region along the tip 126 of the key top surface portion 120.

[0036] In FIG. 6, the area on the tip 126 side from the dotted line shown near the tip 126 is an area where the key upper surface portion 120 protrudes in the D1 direction from the key main body portion 110. The uneven formation area 125 is provided on the D2 direction side from the dotted line. The uneven formation area 125 is provided 3 mm or more on the D2 direction side from the dotted line. That is, the distance between the end portion of the uneven formation area 125 in the D1 direction and the tip 126 is 3 mm or more. As shown in FIG. 3, a part of the lower surface of the key upper surface portion 120 is exposed to the outside, but the recess 121 and the uneven shape 122 are not formed in the area exposed to the outside.

[0037] As shown in FIG. 3, the vicinity of the tip of the key upper surface portion 120 protrudes in the D1 direction. Therefore, the user's finger during performance may contact the vicinity of the tip of the key upper surface portion 120. In particular, when the user's finger collides from below with the vicinity of the tip of the key upper surface portion 120, a force in the direction in which the key upper surface portion 120 peels off from the key main body portion 110 is applied to the key upper surface portion 120 due to the collision. However, since the uneven formation area 125 is provided in the vicinity of the tip of the key upper surface portion 120, even when such a force is applied to the key upper surface portion 120, it is possible to suppress the key upper surface portion 120 from peeling off from the key main body portion 110.

[0038] FIG. 7 is a partially enlarged view of the laser irradiation location of the upper surface material of the key in an embodiment of the present invention. FIG. 7 is an enlarged view of a part of the uneven formation area 125 in FIG. 6. As shown in FIG. 7, in the uneven formation area 125, a plurality of recesses 121 are periodically arranged in a plan view. In the example shown in FIG. 7, the plurality of recesses 121 are arranged at equal intervals in the D1 direction and the D3 direction, but the intervals between the recesses 121 adjacent in the D1 direction and the intervals between the recesses 121 adjacent in the D3 direction may be different. The cross-sectional shape of each of the plurality of recesses 121 is the same as the shapes in FIGS. 4 and 5.

[0039] FIG. 8 is a cross-sectional view of the laser irradiation portion of the upper surface member of the key in one embodiment of the present invention. The cross-sectional view shown in FIG. 8 is a cross-sectional view cut along the line A-A' in FIG. 7. Note that the cross-sectional view shown in FIG. 8 is simplified for convenience of explanation, but the actual cross-sectional shape is the same as the cross-sectional views shown in FIGS. 4 and 5. In FIG. 8, mainly the shape of the edge portion of the concave portion 121 and the shape outside the concave portion 121 will be described.

[0040] As shown in FIG. 8, the edge portion 127 of the concave portion 121 protrudes downward. This edge portion 127 is provided around the concave portion 121. The protruding shape of the edge portion 127 is considered to be formed by the movement of the resin material originally present in the concave portion 121 when the concave portion 121 is formed by laser irradiation. In the region outside the edge portion 127, the lower surface of the key upper surface portion 120 is flat. In other words, an uneven shape is provided on a part of the lower surface of the key upper surface portion 120, and in other portions, the lower surface of the key upper surface portion 120 is flat.

[0041] As described above, according to the white key 100 according to the present embodiment, even when a water-soluble adhesive (adhesive layer 150) is used for the adhesion between the wood (key main body portion 110) and the resin material (key upper surface portion 120), the adhesion strength between the two can be improved. Note that even when an organic solvent-based adhesive is used as the adhesive layer 150, the adhesion strength is improved by the undercut shape in the resin material.

[0042] [5. Modification Example] A modification example of the present embodiment will be described with reference to FIGS. 9 to 11. FIG. 9 is a partially enlarged view of the laser irradiation portion of the upper surface member of the key in one embodiment of the present invention. In FIG. 9, unlike FIG. 7, the adjacent concave portions 121 overlap in plan view. As shown in FIG. 9, when the adjacent concave portions 121 overlap, they actually appear to have a continuous shape like the planar shape 128. Even in such a case, it can be said that the concave portions 121 are periodically arranged based on some periodic shapes. Specifically, it can be determined that the concave portions 121 are periodically arranged based on the periodicity of the upper portions 129 of the plurality of overlapping concave portions 121 shown in FIG. 9.

[0043] FIG. 10 is a diagram showing the laser irradiation locations on the upper surface member of the key in one embodiment of the present invention. In FIG. 10, unlike FIG. 6, the uneven formation region 125 is provided not only near the tip 126 of the key upper surface portion 120 but also along the periphery of the key upper surface portion 120. As shown in FIG. 10, the uneven formation region 125 may be provided continuously along the periphery of the key upper surface portion 120, or may be provided discretely along the periphery.

[0044] FIG. 11 is a perspective view of a key in a modified example of one embodiment of the present invention. The white key 900 shown in FIG. 11 is, for example, a white key used in an electronic piano. The white key 900 has a key body portion 910 made of a resin material and a key side surface portion 920 made of wood. The key body portion 910 is integrally formed by resin molding, and a concave portion is formed on its side surface. The key side surface portion 920 is a plate-shaped piece of wood and is adhered so as to be fitted into the concave portion of the key body portion 910.

[0045] Even with such a configuration, by forming a shape similar to the concave portion 121 and the uneven shape 122 shown in FIGS. 4 and 5 on the key body portion 910 made of a resin material, the adhesive strength between the key body portion 910 and the key side surface portion 920 can be improved.

[0046] Even in the above-described modified example, the same effects as those of the present embodiment can be obtained.

[0047] Note that the present invention is not limited to the above-described embodiments and can be appropriately modified without departing from the gist thereof.

Explanation of Reference Numerals

[0048] 10: Keyboard device, 100: White key, 110: Key body part, 120: Key upper surface part, 121: Concave part, 122: Concavo-convex shape, 123: Concave shape, 124: Convex shape, 125: Concavo-convex formation area, 126: Tip, 127: Edge part, 128: Planar shape, 129: Upper part, 130: Key front surface part, 150: Adhesive layer, 200: Pedal, 300: Action mechanism, 400: Hammer, 500: String, 600: Damper, 700: Damper operation mechanism, 800: Stopper, 810: Key sensor, 820: Hammer sensor, 900: White key, 910: Key body part, 920: Key side surface part, P0: Interval, PV: Level difference, R1: Area, R2: Area, TP: Protrusion, W: Width

Claims

1. A key for a keyboard device, comprising: a key body portion made of wood; a key upper surface portion made of resin provided on the upper surface of the key body portion; and an adhesive for bonding the key body portion and the key upper surface portion. A recess is provided on the lower surface of the key upper surface portion. An uneven shape is further formed inside the recess.

2. The diameter of the recess is 20 μm or more and 500 μm or less. The height difference of at least a part of the uneven shape is 20 μm or more. The key according to claim 1.

3. On the lower surface of the key upper surface portion, a first part visible when viewed from the key body portion; and a second part located in the shadow of the first part and not visible when viewed from the key body portion. The key according to claim 2.

4. A key for a keyboard device, comprising: a key body portion made of wood; a key upper surface portion made of resin provided on the upper surface of the key body portion; and an adhesive for bonding the key body portion and the key upper surface portion. On the lower surface of the key upper surface portion, a first part visible when viewed from the key body portion; and a second part located in the shadow of the first part and not visible when viewed from the key body portion.

5. A recess is provided on the lower surface of the key upper surface portion. An uneven shape is formed inside the recess. The key according to claim 4.

6. The adhesive is a water-soluble adhesive. The key according to any one of claims 1 to 5.

7. A plurality of the recesses are provided. The plurality of recesses are arranged periodically in a plan view. The key according to any one of claims 1 to 3 and 5.

8. The uneven shape is provided on a part of the lower surface of the key upper surface portion, and the lower surface of the key upper surface portion in other parts is flat. The key according to any one of claims 1 to 3 and 5.

9. The uneven shape is provided on the lower surface of the key upper surface portion corresponding to a region of 3 mm or more from the tip of the key body portion. The key according to any one of claims 1 to 3 and 5.

10. A first region at the tip of the lower surface of the key upper surface portion protrudes from the tip of the key body portion. The uneven shape is not formed on the lower surface of the key upper surface portion in the first region. The key according to claim 9.

Images