reaction force generator

Abstract

comprising a reaction force generator (10) arranged on a base (93): an elastic structure; and a dome, wherein the dome is made of an elastic element and has a section that curves towards the base (93) and has at least one rebound section (AF) and one click generation section (CL), where a reaction force is generated by elastic deformation of the elastic structure and the dome during a pressing operation in which the elastic structure is pressed, and wherein the rebound section (AF) and the click generation section (CL) are both inclined with respect to the pressing direction in the dome, the click generation section (CL) has an end that is connected to the stop section (AF), and wherein a degree of inclination of a thick section between both ends of the click generation section (CL) with respect to the pressing direction is greater than a degree of inclination of the stop section (AF) with respect to the pressing direction, the dome begins to deform as soon as a distal end section (21) of the dome comes into contact with the base surface (93), after the elastic structure begins to deform during the pressing process, the click generation section (CL) is subjected to compression during the pressing process before the follow-up section (AF) is subjected to significant deformation in order to cause a sudden decrease in reaction force and produce a click sensation, wherein the click generation section (CL) causes a sudden increase in the extent of deformation before the follow-up section (AF), and the follow-up section (AF) is not yet subjected to significant deformation until the click generation section CL is compressed, and The extent of deformation of the post-stop section (AF) increases rapidly after the click-generating section (CL) has been subjected to compression.

Description

Technical area

[0001] The present invention relates to a reaction force generator that generates a reaction force against an operation by elastic deformation of an elastic dome. State of the art

[0002] A conventionally known reaction force generator generates a reaction force against an operation by elastically deforming an elastic dome. For example, the invention according to Patent Literature 1 uses a rubber dome as a key operation detection switch in a keyboard device of an electronic musical instrument. This invention is equipped with a plurality of reaction force generating sections that generate reaction force peaks at different positions upon keystroke by varying the thickness of a wall portion forming the aperture of an outer or inner dome depending on a location. A desired reaction force characteristic is realized by combining characteristics of the plurality of reaction force generating sections. Literature listPatent literature

[0003] Patent Literature 1: JP 06-251652 A

[0004] Document GB 2 112 577 A shows a key switch (reaction force generator) arranged on a base and having an elastic dome. When pressed, a reaction force causes the dome to deform elastically, thereby pushing a post-action portion toward the base. Document DE 41 11 756 A1 shows how an electronic musical instrument can replicate the touch feel of a conventional, mechanical musical instrument. Document CN 1 03 681 056 A also shows how an electronic musical instrument can replicate the touch feel of a conventional, mechanical musical instrument. Brief description of the inventionTechnical problem

[0005] An acoustic piano with an action mechanism produces a click sensation immediately before the hammer strikes the keyboard. Accordingly, the keyboard mechanism of an electronic musical instrument can also provide a preferential actuation sensation by producing a click sensation at a position immediately before the sound moment (key-on) when the key is struck. This click sensation is generated due to a difference in reaction force, so the reaction force peaks during the keystroke.

[0006] However, in keyboards that use a rubber dome switch as a keystroke detection mechanism, the deformation of the panel wall section typically begins at a curved portion of the wall section and gradually expands from there. Thus, it is difficult to generate a clear reaction force peak during keystroke and produce the click feeling. Even if the reaction force peak occurs during keystroke, the click feeling will be accompanied by a strange feeling unless the peak position is properly aligned with the sound moment, and the reaction force peak must occur at an accurate position.

[0007] It should be noted that a change in reaction force such as the click feeling is useful not only for the keyboard device but for various devices, and thus the characteristic and the position of occurrence of the change in reaction force must be appropriately determined depending on an operator of each device.

[0008] An object of the present invention is to provide a reaction force generator that generates a click feeling at an appropriate position upon a pressing stop. Solving the task

[0009] According to the present invention, a reaction force generator is provided which is arranged on a base surface, has an elastic structure and a dome made of an elastic member and has a portion that bulges toward the base surface and has at least a post-strike portion and a click-generating portion, and which generates a reaction force by elastically deforming the elastic structure and the dome during a pressing operation in which the elastic structure is pressed, wherein the post-strike portion and the click-generating portion are both inclined with respect to the pressing direction, and wherein the click-generating portion has one end connected to the post-strike portion, and an inclination degree of a thick portion between both ends of the click-generating portion with respect to the pressing direction is greater than an inclination degree of the post-strike portion with respect to the pressing direction,wherein the dome begins to deform as soon as a distal end portion of the dome comes into contact with the base surface after the elastic structure begins to deform during the pressing process, wherein the click-generating portion is subjected to compression during the pressing process to cause a sudden decrease in the reaction force and generate a click feeling, wherein the click-generating portion causes a sudden increase in a deformation amount before the post-strike portion, and wherein the deformation amount of the post-strike portion increases rapidly after the click-generating portion has been subjected to compression. Short description of the drawings Fig. 1 is a schematic diagram schematically illustrating a part of the configuration of a keyboard device of an electronic musical instrument to which a reaction force generator according to a first embodiment of the present invention is applied. Fig. 2 is a schematic diagram schematically illustrating a part of the configuration of a variation of the keyboard device of an electronic musical instrument to which a reaction force generator according to the first embodiment of the present invention is applied. Fig. 3 is a longitudinal sectional view of a key switch serving as a reaction force generator according to the first embodiment of the present invention. Fig. 4 is a graph showing a reaction force characteristic of an inner dome in Fig. 3 illustrates. Fig. 5A to 5F are process images showing transitions from deformations of the key switch to Fig. 3 during the pressing process. Fig. 6 is a longitudinal sectional view of a key switch serving as a reaction force generator according to a second embodiment of the present invention. Fig. 7 is a longitudinal sectional view of a variation of a key switch serving as a reaction force generator according to the second embodiment of the present invention. Fig. 8 is a longitudinal sectional view of a key switch serving as a reaction force generator according to a third embodiment of the present invention. Fig. 9A to 9F are process images showing transitions from deformations of the key switch to Fig. 8 during the pressing process. Fig. 10A to 10C are process diagrams illustrating transitions of deformations of an inner dome of a conventional key switch during its pressing operation. Fig. Figure 11 is a graph illustrating reaction force characteristics of the inner dome of the conventional key switch. Fig. 12 is a longitudinal sectional view of a key switch serving as a reaction force generator according to a fourth embodiment of the present invention. Description of embodiments

[0010] Embodiments of the present invention will now be described with reference to the drawings.

[0011] Fig. 1 is a schematic diagram schematically illustrating a part of the configuration of a keyboard device of an electronic musical instrument to which a reaction force generator according to a first embodiment of the present invention is applied. The keyboard device includes keys 92 as a plurality of execution actuators. Fig. However, FIG. 1 illustrates only one key 92 representative of the plurality of keys. A substrate 93 is disposed below the key 92, and a key switch 10 is disposed on the substrate 93 as a reaction force generator. When pressed, the key 92 rotates about an axis 91 to drive the key switch 10. Driving the key switch 10 causes a musical tone generator (not shown) to generate a musical tone signal and a reaction force to be applied to the key 92, as described in more detail below. This reaction force gives a performer the feeling as if they are playing an acoustic piano.

[0012] It should be noted that a driver driving the key switch 10 is not limited to the key 92, but can be a hammer. As shown in Fig. 2, for example, a hammer 95 is always engaged with the key 92 through a drive transmission section 94 so that driving force can be transmitted from the key 92 to the hammer 95. The hammer 95 is arranged rotatably around an axis 98. The substrate 93 is arranged above the hammer 95, and the key switch 10 is arranged on a lower surface of the substrate 93. When the key 92 is pressed, the hammer 95 is driven by the drive transmission section 94 and rotates around the axis 98 to drive the key switch 10. Note that the position where the substrate 93 and the key switch 10 are arranged is not limited to the top of the hammer 95, but may be below the hammer 95 between the drive transmission section 94 and the axis 98.

[0013] The configuration of the key switch 10 is substantially the same as a conventional configuration in which a movable contact and a fixed contact form a contact switch. Fig. 3 and 5A to 5F illustrate an example in which the key switch 10 is of the one-make type having a switch corresponding to the key 92.

[0014] Fig. 3 is a longitudinal sectional view of the key switch 10 in Fig. 1 and Fig. 2. The key switch 10 has a base portion 11, an outer dome Dout, and an inner dome Din, and is integrally formed from an elastic member such as rubber, except for a carbon portion. The outer dome Dout has a head portion 12 that is pressed to be driven by a driver 96. The driver 96 corresponds to the key 92 or the hammer 95. A center line C0 in Fig. 3 is substantially parallel to the direction of pushing applied by the driver 96. Strictly speaking, the pushing direction may change gradually during a pushing and driving operation, but the pushing direction at the time when the driver 96 comes into contact with the head portion 12 or when the inner dome Din (described below) generates a reaction force peak can be defined as a representative pushing direction. Alternatively, starting from a flat upper surface as the contact surface of the head portion 12 to be in contact with the driver 96, a direction perpendicular to the upper surface of the head portion 12 can be defined as the pushing direction. When viewed from an axial direction of the center line C0, the outer dome Dout and the inner dome Din are concentric circles with the center line C0 passing through their centers.The outer shape of the base portion 11 may be any shape, such as a rectangle when viewed from above.

[0015] The head portion 12 of the outer dome Dout is pressed by the driver 96 during the pressing operation (which corresponds to a forward key press operation), thereby generating a reaction force against the pressing due to the elastic deformation of the outer dome Dout and the inner dome Din. This reaction force acts as a reaction force against a key press operation, creating a key press feel for the operator.

[0016] The base portion 11 is fixed to the substrate 93, and the outer dome Dout bulges from the base portion 11 in a direction away from a bottom surface 93a of the substrate 93. The inner dome Din is formed on the inside of the outer dome Dout and bulges to a side (toward the bottom surface 93a) opposite the bulge of the outer dome Dout. The base portion 11 and the head portion 12 are connected by a bezel portion 13 having a curved portion. Note that the bezel portion 13 forms part of the outer dome Dout. One end of the head portion 12 is flat.

[0017] The inner dome Din includes, as elements constituting part thereof, a click generation portion CL that mainly plays a role in generating the click feeling, a post-strike portion AF that mainly plays a role in characterizing a change in reaction force after generating a click, and a distal end portion 21. The click generation portion CL is connected to the post-strike portion AF at a connecting portion 24. The connecting portion 24 is one end of the click generation portion CL and also one end of the post-strike portion AF. The click generation portion CL is also connected to the outer dome Dout at a connecting portion 26. The connecting portion 26 is also another end of the click generation portion CL. The connecting portion 26 is also part of a connecting region between the head portion 12 and the bezel portion 13 of the outer dome Dout.The post-stop section AF is connected to the distal end section 21 at a connecting section 22.

[0018] A distal end surface of the distal end portion 21 is a flat surface facing and parallel to the base surface 93a, and a movable contact 27 made of a conductive material such as carbon is formed on the flat surface. A fixed contact 97 made of a conductive material such as carbon is formed in a region on the base surface 93a facing the movable contact 27. The movable contact 27 and the fixed contact 97 form a pair of electrical contacts. A pressing operation is detected by conduction between the contacts, and a detection signal is transmitted (in this case, key-on detection in an execution operation).It should be noted that the present electronic musical instrument includes a CPU and the musical tone generator (not shown), wherein the detection signal of the key switch 10 is supplied to the CPU to cause the musical tone generator to generate a musical tone at a timing corresponding to the detection.

[0019] A pressing end position by the driver 96 is determined in the pressing operation. The pressing end position is controlled, for example, by a stopper (not shown) that controls the end of rotation of the key 92 or the hammer 95. In the pressing operation, a stop from the time the distal end portion 21 comes into contact with the base surface 93a until the end of pressing (end of the execution operation) is hereinafter referred to as an "inner dome stop." The inner dome stop corresponds to a region in the latter half of the keystroke of the key 92. As a result, a click feeling like that of an acoustic piano can be imparted in the latter half of the keystroke.

[0020] The shape of the inner dome Din in the present embodiment is designed so that the click generating portion CL causes a sudden increase in the deformation amount before a sudden increase in the deformation amount of the after-strike portion AF during the pressing operation. Specifically, the rigidity in the pressing direction of the click generating portion CL is made smaller than the rigidity in the pressing direction of the after-strike portion AF. The shape of the inner dome Din is further designed so that, during the pressing operation, the click generating portion CL undergoes compression to cause a sudden decrease in the reaction force and generate a click feeling, and the after-strike portion AF subsequently undergoes a sudden increase in the deformation amount. The detailed configuration of the inner dome Din will be described below.

[0021] First, with respect to the click generation portion CL, a thick portion 25 extends straight between both ends (the connecting portions 24 and 26) and has a uniform wall thickness in a cross section parallel to the center line C0. With respect to the after-stop portion AF, the wall thickness of a thick portion 23 between the connecting portions 24 and 22 gradually increases from the connecting portion 24 toward the distal end portion 21. However, the uniform wall thickness of the thick portion 25 of the click generation portion CL is smaller than or equal to the minimum thickness of the thick portion 23 of the after-stop portion AF.

[0022] When the inclination angles of the thick portions 23 and 25 with respect to the center line are defined in terms of the respective thickness directions of the thick portions 23 and 25, both the click generation portion CL and the after-strike portion AF are inclined with respect to the center line C0 (the pressing direction), and the inclination degree of the thick portion 25 of the click generation portion CL with respect to the pressing direction is greater than the inclination degree of the thick portion 23 of the after-strike portion AF with respect to the pressing direction. That is, the thick portion 23 and the center line C0 form an acute angle θa, while the thick portion 25 and the center line C0 form an acute angle θc, where θc>θa.

[0023] Fig. 4 is a graph showing a reaction force characteristic of the inner dome Din in Fig. 3. A horizontal axis represents a position in the inner dome stop, and a vertical axis represents a reaction force. An upper curve L1 represents a forward action (forward key action), and a lower curve L2 represents a return action (key release action).

[0024] When the distal end portion 21 comes into contact with the base surface 93a at the inner dome stop start position ST0, the inner dome Din begins to generate a reaction force. The reaction force increases immediately but then rapidly decreases due to the compression of the click generation portion CL at position ST1. This generates the maximum value of the reaction force. The reaction force generated by the click generation portion CL remains small after the rapid decrease, whereas the reaction force of the after-stop portion AF begins to increase. The minimum value of the reaction force generated by a resultant force of both the click generation portion CL and the after-stop portion AF occurs at position ST2, and a subsequent increase in the reaction force mainly depends on the after-stop portion AF. The reaction force gradually increases until the pressing end position STE.The minimum value is less than or equal to half the maximum value. This increases the reaction force difference at the inner dome stop, thus emphasizing the click feeling.

[0025] Here, position ST1 and position ST2 are both positioned in the range corresponding to a first half of the inner dome stroke (St0 to STE9 (on the side closer to position ST0 than position STE). This is to sufficiently ensure a change in the reaction force at the after-stroke post-position ST2. No after-stroke or a short after-stroke causes the stroke to end immediately after the click, making the click feeling unclear. Assuming that the key stroke of key 92 is 10 mm, the start position ST0 of the inner dome stroke corresponds to a position 70% (about 7 mm) away from a non-operated position at the key stroke of key 92. Positions ST0, ST1, and ST2 are set in the above-mentioned manner to enable position ST1 to correspond to a stroke position where a click feeling is desired at the time of key stroke.In addition, the minimum value occurs immediately after the maximum value, so that together with the subsequent after-stroke, a clear click feeling can be obtained, even in the range of only 30% of the keystroke.

[0026] Fig. 5A to 5F are diagrams illustrating transitions of deformations of the key switch 10 during the pressing operation thereof. When the head portion 12 is moved from a non-pressed state ( Fig. 5A) is pressed out at the time when no execution operation is performed, the aperture portion 13 of the outer dome Dout first begins to deform. As soon as the distal end portion 21 of the inner dome Din comes into contact with the base surface 93a ( Fig. 5B) the inner dome Din is compressed and begins to generate a reaction force that increases during the pressing ( Fig. 5C and positions ST0 to ST1 in Fig. 4).

[0027] After the click generation section CL receives the compression force reaching a certain level or more, it is next subjected to compression to deform. The reaction force of the inner dome Din generates the maximum value (position ST1 in Fig. 4) and decreases rapidly ( Fig. 5D). This creates a click feeling. The click generating portion CL undergoes a large deformation before the after-strike portion AF due to the configuration difference between the two as described above. First, the thick portion 25 of the click generating portion CL extends straight and is not curved, unlike a conventional configuration in which deformation gradually starts from a curved portion, whereby the click generating portion CL undergoes upsetting, which is an abrupt deformation. Moreover, the wall thickness of the thick portion 25 of the click generating portion CL is less than or equal to the minimum thickness of the thick portion 23 of the after-strike portion AF, and at the same time, the degree of inclination of the thick portion 25 with respect to the pressing direction is greater than the degree of inclination of the thick portion 23 with respect to the pressing direction.Therefore, the thick portion 25, which is not thick, has a large inclination, and has low rigidity in the pressing direction, cannot withstand the compression force and begins to deform first.

[0028] The post-stop section AF is not yet subjected to any significant deformation until the click generation section CL is compressed, but it is subjected to a sudden increase in the amount of deformation immediately after the compression of the click generation section CL ( Fig. 5E). Specifically, when the click generation section CL has already undergone a strong deformation, the post-stop section AF begins to deform so that it is wavy from the connecting section 24. The thick section 23 is thinner because it is closer to the connecting section 24, so the deformation spreads from the thinner side near the connecting section 24 and transitions to the thicker side. Accordingly, the reaction force generated by the post-stop section AF is small at the beginning of the deformation but increases as the deformation shifts to the thick section. The minimum value of the reaction force occurs at the point when the reaction force generated by the inner dome Din begins to increase (position ST2 in Fig. 4). This makes the click feel noticeable. Subsequently, the reaction force of the post-stop section AF gradually increases, and the switch is finally pushed to the end position of the inner dome stop ( Fig. 5F).

[0029] Here, the deformation mode of the inner dome Din is in contrast to that of the conventional configuration. Fig. 10A to 10C are process diagrams illustrating transitions of deformations of an inner dome of a conventional key switch during its pressing operation. Fig. Figure 11 is a graph illustrating a reaction force characteristic of the inner dome of the conventional key switch.

[0030] An inner dome 100 of the conventional configuration has a distinct curved portion where the deformation gradually begins and then spreads to the entire dome ( Fig. 10A to 10C). The deformation thus does not lead to an abrupt mode such as compression, where the reaction force increases gradually ( Fig. 11). Accordingly, the conventional configuration does not generate a reaction force equivalent to a click sensation.

[0031] In the present embodiment, the click generation section CL and the post-strike section AF do not have a large curved shape (round shape) and are thus susceptible to the compression mode at the beginning of deformation. The click generation section CL is designed to be subjected to compression first by adjusting its thickness and inclination angle. Furthermore, the click generation section CL is inclined with respect to the pressing direction, so that the compression position at the strike can be easily provided at any desired position.

[0032] According to the present embodiment, the click generating portion CL causes the sudden increase in the deformation amount before the after-strike portion AF during the pressing operation, so that the click feeling is reliably generated in the first half of the pressing stroke and a after-strike range can be reliably ensured thereafter. As a result, the click feeling can be generated at an appropriate position at the pressing stroke. The deformation amount of the after-strike portion AF increases rapidly after the click generating portion CL is compressed, so that the distinct click feeling can be generated by compression, during which the after-strike portion can be configured not to undergo deformation. As a result, the click feeling can be reliably generated.

[0033] Furthermore, the wall thickness of the thick portion 25 of the click generating portion CL is less than or equal to the minimum thickness of the thick portion 23 of the after-strike portion AF, so that the click generating portion CL can be reliably subjected to compression before the abrupt deformation of the after-strike portion AF. The thickness of the thick portion 23 of the after-strike portion AF gradually changes in cross-section parallel to the pressing direction, so that during the pressing process, the reaction force generated by the after-strike portion AF after generating the click feeling can be gradually increased to generate a minimum value of the reaction force. This can make the click feeling clear.

[0034] The peak value of the reaction force generated by the inner dome Din during the pressing operation is positioned in the first half of the inner dome stop (St0 to STE). The minimum value of the reaction force generated by the inner dome Din is also positioned in the first half of the inner dome stop immediately after the peak value. In addition, the peak reaction force is reached in the first half of a period from the contact between the distal end portion of the inner dome and the base surface to the end of the execution, so that a stop from the peak reaction force to the end of the execution can be increased to make the click feeling more noticeable. As a result, the click feeling can be generated at an appropriate position at the pressing stop of the execution operation.In particular, to achieve such an effect, it is important to generate the reaction force not in the outer dome Dout but in the inner dome Din. That is, the outer dome Dout begins to deform before the switch is turned on and has already generated a reaction force by the time the switch is turned on, making it difficult to generate the maximum reaction force after the switch is turned on. On the other hand, the inner dome Din can easily generate the maximum reaction force after the switch is turned on.

[0035] In the present embodiment, the reaction force generator is configured as the key switch 10 to be applied to the electronic musical instrument, and the movable contact 27 and the fixed contact 97 constitute the pair of electrical contacts for detecting the key pressing operation, whereby the reaction force generator can have a click feeling generation function and an operation detection function related to the execution operation.

[0036] Next, a second embodiment of the present invention will be described. While the first embodiment has one switch corresponding to the key 92, the second embodiment of the present invention has multiple switches corresponding to one key 92.

[0037] Fig. 6 and Fig. 7 are longitudinal sectional views of a push-button switch 10 having two switches and a push-button switch 10 having three switches, respectively. Although not illustrated in detail, a movable contact of each switch SW and a corresponding fixed contact provided on a base surface 93a form a pair of electrical contacts. The switches SW are arranged, for example, in the same direction as a longitudinal direction of the switch 92.

[0038] Fig. 6 illustrates a two-make key switch with two switches SW1 and SW2. Switches SW1 and SW2 have protrusion heights (corresponding to the distances between the distal ends of these switches and the base surface 93a) that are different from each other and make contact in the order of switch SW1 and switch SW2 in a forward key press operation. The characteristic, particularly of the inner dome Din of the key switch 10 described in the first embodiment, is applied to switch SW2, which makes contact second.

[0039] Fig. Figure 7 illustrates a three-make key switch with three switches SW1, SW2, and SW3. The SW switches have protrusion heights that differ from each other and make contact in the order of switch SW1, switch SW2, and switch SW3 in a forward key press operation. The characteristic, particularly of the inner dome Din of the key switch 10 described in the first embodiment, is applied to switch SW2, which makes contact second to last.

[0040] In both of the Fig. 6 and Fig. In the examples illustrated in Figure 7, an inner dome Din is configured so that the maximum value of a reaction force generated by the inner dome Din of the switch SW2 occurs at a striking position where a click feeling is generated upon key striking of an acoustic piano. As a result, a click feeling can be generated at an appropriate position upon pressing an execution operation.

[0041] Next, a third embodiment of the present invention will be described. The inner dome Din of the first embodiment is configured such that the after-stop portion AF is connected to the distal end portion 21, while the click generating portion CL is connected to the outer dome Dout. In the third embodiment of the present invention, the arrangement relationship between a click generating portion CL and a after-stop portion AF is reversed from their arrangement relationship in the first embodiment.

[0042] Fig. 8 is a longitudinal sectional view of a key switch 10 serving as a reaction force generator according to the third embodiment of the present invention. The configuration of an outer dome Dout is similar to that of the first embodiment. In an inner dome Din, the click generating portion CL is connected to the after-strike portion AF at a connecting portion 34. The connecting portion 34 is one end of the click generating portion CL and is also one end of the after-strike portion AF. The click generating portion CL is also connected to a distal end portion 21 at a connecting portion 32. The after-strike portion AF is connected to the outer dome Dout at a connecting portion 36. The connecting portion 36 is also part of a connecting portion between a head portion 12 and a bezel portion 13 of the outer dome Dout.

[0043] With respect to the click generating portion CL, a thick portion 33 extends straight between both ends (the connecting portions 34 and 32) and has a uniform wall thickness in a cross section parallel to a center line C0. With respect to the after-stop portion AF, the wall thickness of a thick portion 35 between the connecting portions 34 and 36 gradually increases from the connecting portion 34 toward the connecting portion 36. However, the uniform wall thickness of the thick portion 33 of the click generating portion CL is less than or equal to the minimum wall thickness of the thick portion 35 of the after-stop portion AF.

[0044] The click generating section CL and the after-strike section AF are both inclined with respect to the center line C0 (the pressing direction). The degree of inclination of the thick section 33 of the click generating section CL with respect to the pressing direction is greater than the degree of inclination of the thick section 35 of the after-strike section AF with respect to the pressing direction. That is, the thick section 33 and the center line C0 form an acute angle θa, while the thick section 35 and the center line C0 form an acute angle θc, where θc>θa.

[0045] Fig. 9A to 9F are process images showing transitions from deformations of the key switch 10 to Fig. 8 during its pressing operation. The transition of deformation in the present embodiment is substantially similar to that in the first embodiment. The main operation is that the click generation portion CL before the after-stop portion AF undergoes a strong deformation when the distal end portion 21 of the inner dome Din comes into contact with a base surface 93a to cause a load applied to the inner dome Din to reach a certain level or more ( Fig. 9A to 9D). That is, the click generating portion is subjected to compression for deformation while exerting the maximum value of a reaction force. The post-stop portion AF is subjected to a sudden increase in the amount of deformation immediately after the click generating portion CL is compressed ( Fig. 9E). At this time, the thickness of the thick portion 35 of the post-stop portion AF is thinner as it is closer to the connecting portion 34, so that the deformation of the thick portion 35 spreads to be wavy from the thin side near the connecting portion 34. The reaction force generated by the inner dome Din reaches the minimum value, and then mainly the reaction force of the post-stop portion AF gradually increases to finally cause the switch to be pushed to an end position of an inner dome stop ( Fig. 9F).

[0046] Consequently, the present embodiment can achieve an effect similar to the first embodiment in generating a distinct click feeling at an appropriate position at the time of pressing stop.

[0047] It should be noted that the configuration of the present embodiment can be applied to the second embodiment ( Fig. 6 and Fig. 7) by changing the configuration of the inner dome Din in Fig. 8 is applied to switch SW2.

[0048] In the above-mentioned embodiments, the thickness of the thick portions 23 and 35 of the after-strike portion AF changes to become thinner toward the click-generating portion CL. However, the thickness may change in a direction opposite to that illustrated above regarding the gradual increase in the reaction force of the after-strike portion AF after the click-generating portion CL first undergoes a large deformation.

[0049] It should be noted that the location where the key switch 10 is arranged is not limited to the surface of the substrate. If the reaction force generation function is only achieved in the key switch 10, the reaction force generator does not need to be configured as the key switch 10 that has the operation detection function. If the operation detection function is omitted, the base surface only needs to be a surface that can withstand the pressing force. Accordingly, the base surface can be configured as part of the configuration of the reaction force generator, or a surface at the location where the reaction force generator is mounted can be used as the base surface.

[0050] Note that in each of the aforementioned embodiments, the driver 96 can be configured to push the head portion 12 of the outer dome Dout by an operator's operation, and thus can be applied to a musical instrument other than a keyboard, such as a contact point switch of a rhythm machine. Furthermore, the operator is not limited to the execution operator but can also be a setting operator. Furthermore, the present invention can be applied to a device other than an electronic musical instrument.

[0051] In each of the above-mentioned embodiments, the key switch 10 includes the outer dome Dout made of bulging rubber as the elastic structure capable of elastic deformation; however, another elastic structure may be included instead of the outer dome Dout. For example, the key switch 10, as shown in Fig. 12, a coil spring 20 enclosing the inner dome Din, and a flange provided at a lower part of the head portion 12 and extending substantially horizontally so as to contact an upper part of the coil spring 20 and receive a reaction force. In this case, the natural length and a spring constant of the coil spring 20 are adjusted so that the coil spring 20 is compressed in front of the inner dome Din when the head portion 12 is pressed.

[0052] Although the present invention has been described in detail based on the embodiments, the present invention is not limited to these specific embodiments, but has various embodiments without departing from the scope of the present invention. Furthermore, the above-mentioned embodiments may be partially combined with each other as appropriate.

[0053] This application claims the benefit based on Japanese Patent Application No. 2015-164766 filed on August 24, 2015, the entire contents of which are incorporated herein by reference. List of reference symbols 10 button switches (reaction force generator) 21 distal end section The inner dome Dout outer dome CL Click generation section AF re-stop section 24, 26, 32, 34 connecting section 23, 25, 33, 35 thick section 93a floor area

Claims

[1] Reaction force generator (10) arranged on a base (93), comprising: an elastic structure; and a dome, the dome being made of an elastic member and having a portion which bulges towards the base surface (93) and having at least a post-stop portion (AF) and a click generating portion (CL), where a reaction force is generated by elastic deformation of the elastic structure and the dome during a pressing operation in which the elastic structure is pressed, and wherein the post-stop portion (AF) and the click generating portion (CL) are both inclined with respect to the pressing direction in the dome, the click generating portion (CL) has one end connected to the after-stop portion (AF), and wherein an inclination degree of a thick portion between both ends of the click generating portion (CL) with respect to the pressing direction is greater than an inclination degree of the after-stop portion (AF) with respect to the pressing direction, the dome begins to deform as soon as a distal end portion (21) of the dome comes into contact with the base surface (93) after the elastic structure begins to deform during the pressing process, the click generating portion (CL) is subjected to compression during the pressing operation before the after-stop portion (AF) is subjected to a significant deformation to cause a sudden decrease in the reaction force and to generate a click feeling, wherein the click generating portion (CL) causes a sudden increase in a deformation amount before the after-stop portion (AF), and the after-stop portion (AF) is not yet subjected to a significant deformation until the click generating portion CL is compressed, and the deformation amount of the after-stop portion (AF) increases rapidly after the click generation portion (CL) is subjected to upsetting. [2] The reaction force generator (10) according to claim 1, wherein the thick portion extends straight between both ends of the click generating portion (CL) and has a uniform wall thickness in a cross section parallel to the pressing direction. [3] The reaction force generator (10) according to claim 2, wherein the uniform wall thickness of the click generating portion (CL) is smaller than or equal to a minimum thickness of a thick portion of the after-stop portion (AF). [4] The reaction force generator (10) according to claim 1, wherein the thickness of the thick portion of the post-stop portion (AF) gradually changes in a cross section parallel to the pressing direction. [5] The reaction force generator (10) according to claim 1, wherein the elastic structure is made of the elastic member, has a dome shape having a portion bulging away from the base surface (93), and enclosing the dome. [6] The reaction force generator (10) according to claim 1, wherein a peak value of the reaction force generated by the dome in the pushing operation is positioned in a first half of a dome stopper lasting from the contact between the distal end portion (21) of the dome and the base surface (93) to an end of the execution operation. [7] The reaction force generator (10) according to claim 6, wherein a minimum value of the reaction force generated by the dome after the click generating portion (CL) is subjected to compression in the pressing operation is positioned in the first half of the dome stopper. [8] The reaction force generator (10) according to claim 6, wherein each pair of electronic contacts that detect the execution operation by conduction is formed on the distal end portion (21) of the dome or on the base surface (93) facing the distal end portion (21). [9] The reaction force generator (10) according to claim 1, wherein the reaction force generator (10) comprises a plurality of domes, one of the domes has at least the click generating section (CL) and the after-stop section (AF), a plurality of electrical contacts which detect the execution operation by conduction are formed respectively on the distal end portion (21) of each of the domes and on the base surface (93) facing the distal end portions (21), a distance between the distal end portion (21) of each of the plurality of domes and the base surface (93) at the time when no execution operation is performed is different for each dome, the domes begin to deform in the order of contact between the distal end portion (21) and the base surface (93) after the elastic structure begins to deform during the pressing process, and the dome having the click generating portion (CL) is a dome which comes into contact with the distal end portion (21) which comes into contact with the base surface (93) which is the second to last in the pressing operation, and wherein the click generating portion (CL) is subjected to compression in the pressing operation to cause a sudden decrease in the reaction force and to generate a clicking feeling. [10] The reaction force generator (10) according to claim 1, wherein the reaction force generator (10) comprises two of the domes, one of the two domes has at least the click generating section (CL) and the after-stop section (AF), a plurality of electrical contacts which detect the execution operation by conduction are formed respectively on the distal end portion (21) of each of the domes and on the base surface (93) facing the distal end portions (21), Distances between the distal end portions (21) of the two domes and the base surface (93) are different from each other at the time when no execution operation takes place, the domes begin to deform in the order of contact between the distal end portion (21) and the base surface (93) after the elastic structure begins to deform during the pressing process, and the dome having the click generating portion (CL) is a dome which comes into contact with the distal end portion (21) which is the second base surface (93) in the pressing operation, and wherein the click generating portion (CL) is subjected to compression in the pressing operation to cause a sudden decrease in the reaction force and to generate a clicking feeling. [11] The reaction force generator (10) according to claim 9, wherein a deformation amount of the after-stop portion (AF) increases rapidly after the click generating portion (CL) is subjected to upsetting in the pressing process.

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