JPH04178693A - Key driving device of keyboard musical instrument - Google Patents

Abstract

PURPOSE:To improve the fidelity in reproduced performance by providing coils disposed to face keyboards, core members, yoke members, and plungers on a rack between the inside of reeds and the front of the reeds and disposing these members in such a manner that the front ends thereof face the above- mentioned core members in proximity thereto at the time of operation. CONSTITUTION:The common lower yoke 29 is supported on the rack 13 between a balance rail 14 and a front rail 20 and the coils 32, 33 are erected therein in correspondence to respective keys 11, 12. The cores 36, 37 are respectively fixed to the bottom of the axial central parts of the respective coils. The plungers 40, 41 are provided pendently on the rear surface of the upper keys 11, 12 in correspondence to these cores. Both of the opposite surfaces of the plungers 40, 41 and the cores 36, 37 are formed of slopes to approximately the same shapes to decrease magnetic reluctance. The working point of the driving force on the keys 11, 12 at the time of automatic performance is forward of the rail 14 in this way and since the direction of the working force is similar to the direction thereof at the time of manual performance, the faithful reproduction is executed.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a key drive device for a keyboard instrument, and the present invention relates to a key drive device for a keyboard instrument. A plunger with an inclined surface on its tip is placed in the space between the keys, and a plunger with an inclined surface on its tip is suspended from the lower surface of the key. By arranging a magnetic material with a corresponding slope, it is possible to prevent the generation of noise when playing back a player piano.
This improves the fidelity and improves the ease of implementation of the key drive device.

<Prior Art> Conventionally, a key drive device for a player piano has been proposed, for example, in Japanese Unexamined Patent Publication No. 62-212694.

That is, an electromagnetic solenoid equipped with a plunger that protrudes in response to energization is arranged between the middle of the reed and the rear of the reed on the lower surface of the rear end of the key, and the protrusion of the plunger pushes the key from below. This is a technology in which a plunger contacts the bottom surface to drive the key.

<Problems to be Solved by the Invention> However, in such conventional techniques, the point of action of the key driving force is between the middle of the reed and the back of the reed during automatic performance. Unlike the point of application of the key pressing force (the tip of the key), the direction of the force acting on this key is also opposite, so in order to achieve a playback performance that is faithful to the actual pianist's performance, this point is important. Improvement was needed.

There was also a need to suppress noise generation when the plunger abuts the bottom surface of the key.

Furthermore, regarding the arrangement position of the key drive device on the rear end side of the keys, there is no regulation in the specification of the arrangement on the rear end side of the keys of the player piano, so there is no compatibility in opening between pianos.

Therefore, an electromagnetic solenoid is installed between the reed and the radiation. An improved technique has also been devised in which the plunger is mechanically coupled to the key and the suction of the plunger pulls down the key.

However, since the solenoid plunger and the key are mechanically connected in this device, there are problems with the key touch by the pianist when recording the performance, and there is also a problem with mechanical strength, and this improved technology still remains. It wasn't enough.

Therefore, the purpose of the great invention is to provide a key drive device for a keyboard instrument that can improve the fidelity of playback performance, eliminate noise, adverse effects on key touch, etc., and improve the ease of implementation. It is said that

<Means for Solving the Problems> The present invention provides a cylindrical body that is placed on a shelf between the inside of the reed and the radiator, facing the key, and generates a magnetic field along the swinging direction of the key. a coil, a core member made of a magnetic material disposed at the bottom of the plunger loose fitting hole of the coil, a yoke member disposed at at least one of the upper end or the lower end of the coil, and a lower surface of the key. a plunger that hangs down from a position facing the coil and is retractable into the plunger loose fitting hole, and when the plunger is inserted into the plunger loose fitting hole, the tip thereof approaches the core member. FIS drive of a keyboard instrument in which the plungers are arranged so as to face each other, and both the tip surfaces of the plungers and the opposing surface of the core member are formed by inclined slopes so that both surfaces have substantially the same shape. It is a device.

<Operation> In the key drive device according to the present invention, a magnetic field is generated through the yoke member and the core member by energizing the coil, and the plunger is attracted toward the core member by this magnetic field. That is, the key is driven down. In this case, the tip surface of the plunger and the upper surface of the core member opposing this are:
They are formed by inclined slopes so as to have approximately the same shape, thereby shortening the gap through which the magnetic flux passes and increasing the force that attracts the plunger.

This plunger operates without contacting the core member. Therefore, the occurrence of mechanical noise during automatic performance can be completely eliminated, and key touches during manual performance do not give a sense of discomfort.

Further, since the attracted plunger is immersed in the plunger loose fitting hole of the coil, the key drive device as a whole can be configured to be thin.

Further, the key driving force in automatic performance can be applied to the keys in the same direction and at approximately the same position as the key pressing force in manual performance, thereby increasing the fidelity of playback performance.

In addition, by placing a coil between the reed and the radiation, which have key layout standards, it is easier to standardize the key drive device.
That compatibility can be achieved. This is because the space between the middle of the reed and the radial part has approximately the same shape in many pianos.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing a piano key drive device according to an embodiment of the present invention. FIG. 2 is a plan view showing the arrangement thereof, and FIG. 3 is a graph showing the thrust characteristics of the solenoid according to one embodiment.

As shown in Figures 1 and 2, all keys (white key 11
, the black key 12) is placed on the shelf board 13 (balance rail) 1
It is supported so as to be swingable in the vertical direction using the balance bins 15 and 16 installed at 4 as fulcrums.

Further, 17.18 indicates the front bin, and 19.20 indicates the front rail (radiation). 21 is a keyboard presser.

Here, on this shelf board 13! A key drive unit 22 and a key sensor unit 23 are disposed in the space below 11.12 and between the balance rail 14 and the front rail 20.

The key drive unit 22 is supported on the shelf board 13 by a key drive unit support mechanism 24 so that its height, inclination, etc. can be adjusted.

That is, the key drive unit 22 includes a solenoid 25 for driving the white key 11 and a solenoid 2 for driving the black key 12.
6. These solenoids 25,26 are attached to a common lower yoke 29 supported by bolts 27,28.
As shown in FIG. 2, they are arranged and supported in a staggered manner.

30.31 is a spring and this bolt 27.28
It is interposed between the head of the head and the shelf board 13.

The common lower yoke 29 in the form of a strip is as shown in FIG.
It is formed into a shallow box shape and has a cylindrical coil 32 inside.
．． 33 are erected in a staggered manner as described above, corresponding to each key 11, 12. Therefore, each coil 32.33
Plunger loose fitting holes 34 and 35 are respectively formed in the shaft center portions.

And the bottom of these plunger loose fitting holes 34 and 35,
That is, cores 36 and 37 made of a magnetic material such as soft iron are fixed to the upper surface of the common lower yoke 29, respectively. Recesses 38 and 39 are formed in the upper surfaces of these cores 36 and 37, respectively. The recesses 38, 39 are in the shape of a dome, and have flat bottom surfaces 38A, 39A and a conical inclined surface 38B.
, 39B.

On the other hand, on the lower surface of 111.12 above these plunger loose fitting holes 34.35, plungers 40.41
is hanging down. These plungers 40, 41 are disposed in respective plunger loose fitting holes 34, 35 so as to be freely retractable, and are arranged in a staggered pattern as a whole.

The tips of these plungers 40 and 41 are connected to the core 36.
．． It is formed in a shape corresponding to the concave portions 38 and 39 of No. 37, that is, a truncated conical shape. Therefore, this tip part has flat surfaces 40A and 41A of constant diameter and a conical slope 40B.
, 41B.

Note that 42 and 43 are the armature, while 44 is the coil 3.
2.33 is a common upper yoke disposed at the upper end.

Further, a heat sink 45 such as an aluminum plate is fixed to the lower surface of the common lower yoke 29, and a heat vibrator 46 for heat radiation is held on the heat sink 45. These heat sinks 45 and heat vibes 46 cause the solenoid 25.2 to
The heat generated in step 6 is radiated.

The key sensor unit 23 is located between the key drive unit 22 and the balance rail 14 and is located between the keys 11 and 11.
It is located below.

This key sensor unit 23 includes a board 47 and a board 47.
and an optical sensor 48 fixed thereon. Optical sensors 48 are provided corresponding to each 1111.12.

The optical sensor 48 is a reflected light type sensor, and is a sensor of a reflected light type.
The lower surface of the keys 11 and 12 is irradiated with light from a light emitter, and the light reflected from the lower surface is received by a light receiver, thereby continuously detecting the amount of displacement of the keys 11 and 12.

The photoelectric conversion output of the optical sensor 48 is input to a controller 49, and the controller 49 performs feedback control so that the displacement of the keys 11 and 12 becomes a target value. That is, by detecting the displacement of the keys 11 and 12, the coil 32
．． This controls the power supply to 33.

Therefore, in the solenoid 25 (26), when the coil 32 (33) is energized under the control of the controller 49, the generated magnetic field causes the core 36 (37) to be energized.
becomes magnetized and attracts plunge +40 (41). As a result, the key 11 (12) swings downward, and its tip descends to the position indicated by the imaginary line X in FIG. In this way, automatic performance is performed.

In this automatic performance, the driving force (
The point of action of the pull-down force is in front of the balance rail 14, and the direction of the action is from top to bottom, so the keys 11 (12) cannot perform the same movements as during recording. , the reproduction can be performed faithfully.

At this time, as shown in the figure, the plunger 40 (41) is recessed into the plunger loose fitting hole 38 (39), and its tip approaches and opposes the core 36 (37).

In this case, since the tip of the plunger 40 (41) is formed in the shape of a truncated cone, the slope 40B (41B) and the slope 38B (39
B), the characteristics of the suction force and stroke of the plunger 40 (4, 1) can be made smooth.

FIG. 3 shows the relationship between the suction stroke St and the suction force (thrust force) F in this solenoid 25 (26).

In the figure, the curves x, y, and z are each connected to the coil 32.
The power applied to (33) is 100W and 50W.

It shows the relationship between thrust and stroke depth in the case of 20W.

These curves X! As shown at y+Z, when the stroke depth (displacement between the plunger 40 and the core 36) is large, the thrust force for this stroke acts in a substantially smooth state. If the applied power is constant, key 1
1 (12), when the pull-down starts, it is pulled down with a constant force compared to the middle of the pull-down.

Further, as described above, the tip surfaces 40A, 40B (41A, 41B) of the plunger 40 (41) and the core 36 (
Since the opposing surfaces 38A, 38B (39A, 39B) of 37) are formed by inclined slopes and have substantially the same shape, the distance (gap) between them can be reduced, and the magnetic resistance can be reduced. Therefore, ul(
12) The responsiveness at the start of the pulling operation can be improved.

Note that the shape of the tip of the plunger 40 (41) and the recess 3B (3
The shape of 9) is not limited to the shape shown in the above embodiment. Other shapes may be used, for example, shapes having one or more inclined surfaces that intersect with the flat surface of the tip in a straight line. It is also possible to form a recess in the plunger and a protrusion in the core. By forming the wedge shape and the shape that loosely fits therein, it is possible to reduce the force acting in a direction parallel to the wedge-shaped tip plane and the wedge-shaped inclined surface that follows, thereby making it possible for playback performance. At the same time, the influence of the acting force on the ghee support portion can be reduced.

Further, according to the above embodiment, it is easy to set the thrust of the solenoid 25 (26) within a practical value range. The speed can be 3 m/s.

In the above embodiment, the key sensor unit 23 detects the falling speed of the key 11 (12), and the controller 49 performs feedback control to adjust the current supplied to the coil 32 (33), thereby further improving the regeneration. Fidelity can be improved.

Further, since the plunger 40 (41) is configured to be recessed into the plunger loose fitting hole 34 (35) of the coil 32 (33), the key drive unit 22 as a whole can be configured to be thin.

<Effects of the Invention> As explained above, according to the key drive device for a keyboard instrument according to the present invention, the force acting on the keys can be approximated to that of manual performance, improving the fidelity of playback performance. be able to. Further, it is possible to completely eliminate the generation of noise during playback performance and manual performance. Furthermore, there is no discomfort when touching the keys during normal performance. In addition, during playback performance, the driving force of the keys can be improved, the structure can be made thinner, and the entire device can be used in common, improving the ease of mounting on keyboard instruments.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a key driving device according to an embodiment of the present invention, Section 2 is a thousand-sided view showing the key driving device, and FIG. 3 is a thrust force of a solenoid according to an embodiment of the present invention. It is a graph showing characteristics. II: White key, 12: Black key, 13: Shelf board, 14: Balance Rail (discharge), 19
(20)...Front rail (unloaded), 25(
26)... Solenoid, 29...
・Common lower yoke, 32 (33)... Coil, 34 (35)... Plunger loose fitting hole, 36 (3
7)・・・・・・Core, 38(39)・・・・
...Concave part, 38A (39A) ...Bottom surface, 38B (39B) ...Slope surface, 40 (41)-φ ...Plunger, 4OA (41A
)...Flat surface, 40B, 41B)...Conical slope, 44...Common upper yoke. Patent applicant: Yamaha Corporation Representative: Patent attorney: Kiyoshi Kuwai

Claims (1)

[Claims] Disposed on a shelf between the middle of the reed and the front of the reed, facing the key,
a cylindrical coil that generates a magnetic field along the rocking direction of the key; a core member made of a magnetic material disposed at the bottom of the plunger loose fitting hole of the coil; and one of the upper and lower ends of the coil. a yoke member disposed on at least one side; and a plunger that hangs down from a position facing the coil on the lower surface of the key and is provided so as to be retractable into the plunger loose fitting hole, the plunger being a plunger. When the plunger is inserted into the loose fitting hole, the plunger is disposed so that its tip is close to and faces the core member, and both the tip surface of the plunger and the opposing surface of the core member are arranged so that both sides are substantially the same. A key drive device for a keyboard instrument, characterized in that it is formed by a slope that slopes to form a shape.