JPH0414097A - Key driving device of keyboard musical instrument - Google Patents

Abstract

PURPOSE:To decrease the number of components and to suppress a magnetic leak by arranging the upper yoke on the reverse surface of a key opposite closely to a lower yoke on a shelf plate composed of individual yokes with coils which are arranged zigzag on both sides of a common yoke. CONSTITUTION:When a voltage is applied to the coil 34 of the key driving device 30 corresponding to a specific key 31, the upper yoke 35 on the reverse surface of the key is attracted to the lower yoke 33 to strike on it with strength corresponding to the voltage. The yokes 35 and 33 are held not in contact at all times, so the generation of a mechanical noise is prevented to relieve a feeling of physical disorder at the time of key depression. The device 30 consists of four members, i.e. the coil 34, and the upper, lower, and common yokes to decrease inspection items and also realize high productivity. Further, the individual yokes 37 are arranged zigzag to suppress the lead of a magnetic field generated by coils 34 between adjacent devices 30, a magnetic circuit is shortened, and the thrust to the stroke of the keys is smoothed and made large.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a key drive device that electrically swings the keys of automatic keyboard instruments such as automatic pianos and electronic pianos.

[Prior Art] Conventionally, as this type of key drive device, the key driving device shown in FIG. 6 or 7 has been used.
The structure shown in the figure is known.

The former key driving device l, as shown in FIG. and the plunger 2&, which is swingably mounted on the back surface of the key 3, and the coil 2b, which is mounted on the shelf board 5.
A yoke 2 is provided surrounding this coil 2b.
By applying a driving voltage to the coil 2b based on a performance signal output from a separately provided control unit, the granger 2a is attracted and the key 3 is pulled down. It is made to swing like this.

In addition, the latter key drive device 10, as shown in FIG.
A sliding solenoid 11 is provided on the opposite side of the balance rail 4 from the player side, and by pushing the plunger lla of this solenoid H toward the back of the key 3, the key 3 is swung upward. It was designed so that

By the way, in the former case, since the sliding type solenoid 2 is used, there is a problem that mechanical noise is likely to be generated due to sliding between the plunger z1 and the yoke 2c when the key 3 swings. ing.

Furthermore, since the weight of the plunger 2 acts on the key 3 and the sliding resistance of the plunger 21 is added when the key 3 is swung, the operational feel when playing the key 3, so-called touch feeling, is adversely affected. Induce the result of giving.

In the latter case, in addition to the mechanical noise caused by the sliding of the plunger lla similar to the former case, there is a collision sound between the plunger lla and the key 3 due to the distance between the plunger lla of the solenoid 11 and the key 3. Occur.

Furthermore, in the latter case, since the plunger lla and the key 3 do not move in a unified manner, the operation fluctuates when repeatedly struck.

This has a serious adverse effect on faithful reproduction such as repeated hits.

Furthermore, in both cases, the relationship between the thrust force of the plunger 21 and lla with respect to the stroke of the key 3 becomes steep, which is unfavorable in terms of control during automatic performance.

In order to deal with such problems, the applicant of the present application,
A key drive device 2° shown in FIGS. 8 and 9 was devised.

This key drive device 20 is disposed on a shelf board 5 closer to the player than a balance rail (not shown), and includes a coil 21 that generates a magnetic field in a direction substantially perpendicular to the swing direction of the key 3, and a coil 21 that generates a magnetic field in a direction substantially perpendicular to the swinging direction of the key 3. A lower yoke 22 is provided upright at both ends in the key arrangement direction of the coil 21 and has an inclined side surface Ha expanding from the key 3 side toward the shelf board 5 side, and the lower yoke 22 is connected to the lower yoke 22 passing through the center of the coil 21. a center yoke 23 fixed to the back of the key 3 at a position facing the coil 21, and an inclined surface 24a corresponding to the inclined side surface 22a of the lower yoke 22;
These coils 21° are composed of a pair of lower yokes 22 and a center yoke 23,
They are arranged linearly for each key in the direction in which the keys 3 are arranged.

With this configuration, during the suction operation of the upper yoke 24, the upper yoke 24 is always kept in a non-contact state with respect to the lower yoke 22, and mechanical noise is prevented from occurring when the key 3 is operated or driven. This prevents the user from feeling uncomfortable when operating the key.

Further, since the upper yoke 24 is shaped to surround the lower yoke 22, a magnetic circuit with less leakage is formed, thereby smoothing out changes in the thrust force with respect to the stroke of the upper yoke 24.

This has achieved the following effects.

[Problems to be Solved by the Invention] However, even in the key drive device 20 according to the above-mentioned proposal, the following points still remain to be improved.

That is, the magnetic shielding between adjacent key drive devices 20 is still insufficient, and there are cases where mutual interference occurs.

Also, for one g13, a coil 21, a pair of lower yokes 22, a center yoke 23, and an upper yoke 24
The number of parts is large, and it is necessary to reduce the number of parts by at least one part in order to save labor in parts inspection and assembly.

Therefore, it has been desired to address these problems in the prior art, and the present invention aims to solve these remaining problems in the prior art.

[Means for Solving Problem L] The present invention aims to provide a key drive device for a keyboard instrument that can effectively solve the above-mentioned problems. A lower yoke disposed on a plate, a coil provided on the lower yoke, and an upper yoke disposed on the back surface of the key so as to be close to and opposite to the lower yoke, the lower yoke comprising: Consisting of a common yoke arranged along the direction in which the keys are arranged, and individual yokes arranged in a staggered manner on both sides of the common yoke in the longitudinal direction and around which the coil is wound. It is characterized by

[Function] The key drive device for a keyboard instrument according to the present invention generates a magnetic field by applying a voltage to the coil, and thereby,
The upper yoke is moved toward the lower yoke by suction.

During this movement, the upper yoke is always moved in a non-contact state with respect to the lower yoke.

The lower yoke is composed of a common yoke and an individual yoke provided for each key, and by winding a coil around this individual yoke, the number of parts is reduced to 4 for 6 keys, and , a common yoke is shared for each tin amount to reduce the number of parts.

Furthermore, by arranging the individual yokes in a staggered manner, magnetic leakage is suppressed.

[Example] An example of the present invention will be described below with reference to FIGS. 1 to 5.

As shown in FIGS. 1 and 2, the key drive device 30 shown in this embodiment has a key 3! auxiliary center (balance rail R)
The lower yoke 3 is arranged on the shelf board 32 closer to the player side.
3, the coil 34 provided on this lower yoke 33, and the key 3! As shown in FIG. 2, an upper yoke 35 is provided on the back surface of the yoke 35, which is disposed close to and opposite to the lower yoke 34,
The lower yoke 33 is connected to the key 3I as shown in FIG.
A common yoke 36 is arranged along the arrangement direction of the common yoke 36, and individual yokes 3 are arranged on both sides of the common yoke 36 in a staggered manner and around which the coil 34 is wound.
It has a general configuration including 7.

Next, to explain these details, the shelf board 3
As shown in FIG. 2, a substrate 38 is provided on the top surface of the substrate 38, and a heat transfer plate 39 made of a metal with good thermal conductivity such as an aluminum alloy is provided on the top surface of the substrate 38. , the key driving device 30 is mounted on the upper surface of this heat transfer plate 39.

As shown in FIGS. 2 and 3, the common yoke 36 constituting the lower yoke 33 has a cross-sectional shape along the auxiliary direction of the key 31 that gradually narrows upward (toward the key 31).
It is formed into a substantially trapezoidal shape with two inclined surfaces 36a and 36b, and recesses 36c that open downward are formed at the lower end of the trapezoid, and the heat exchanger plates are formed on both sides in the longitudinal direction. Base plate 4 that covers almost the entire surface of 39
A heat pipe 41 that contacts the heat transfer plate 39 and exchanges heat with the heat transfer plate 39 is fitted in the recess 36c.

Further, as shown in FIG. 1, the base plate 40 has rectangular through holes 42 on both sides of the common yoke 36 at the same pitch as the arrangement pitch of the keys 31 and at a constant pitch with the common yoke 36. They are formed in a staggered pattern at intervals.

As shown in FIGS. 2 and 3, the cross-sectional shape of each of the individual yokes 3 along the direction of movement of the key 31 is an inclined surface similar to that of the common yoke 36! 7a and 37b, and is formed into a substantially rectangular shape in plan view, with a fitting protrusion 37c protruding from the bottom surface having the same cross-sectional shape as the through hole 42 formed in the base plate 40. has been done.

Each individual yoke 37 is connected to the fitting protrusion 3? c is fitted into the through hole 42 of the base plate 40, so that it is attached to the base plate 40 so as to protrude upward.

Therefore, these individual yokes 37 are provided on both sides of the common yoke 36 in a staggered manner.

The coil 34 is wound around a pobbin 43 disposed so as to surround the lower outer periphery of each individual yoke 37, and generates a magnetic field along the direction in which the individual yokes 37 protrude, that is, the direction in which the key 31 is assisted. It is designed to allow

The upper yoke 35 is fixed to the back surface (lower surface) of the key 31 with, for example, wood screws or bolts, and has a pair of recesses 44 and 45 into which the common yoke 36 and the individual yokes 37 are inserted. ing.

Each of these recesses 44 and 45 corresponds to the key 3! When the is moved to the lowest position, as shown in Figure 2,
Each inclined surface 36a of the common yoke 36 and the individual yokes 37
- Inclined surfaces 3Sa-35d are formed to be substantially parallel to 36b-37a-37b at a predetermined interval.

Next, the operation of this embodiment configured as described above will be explained.

According to the automatic performance program, a voltage according to performance information is applied to the coil 13 of the key driving device 30 corresponding to a predetermined key 11, and a magnetic field according to this voltage is generated by the coil 34, and the upper yoke 3S is sucked toward the lower yoke 33.

As a result, the key 31 is swung together with the upper yoke 5, and the string-striking mechanism of the automatic piano I is activated to strike the strings with a strength corresponding to the voltage.

Further, in an electronic keyboard instrument, a switch of a sounding device is operated by the key 31 to produce sound.

In such a suction operation of the upper yoke 35, the upper yoke 35 is always kept in a non-contact state with respect to the lower yoke 33, so that mechanical noise is prevented from occurring and the discomfort felt when pressing a key is alleviated. Ru.

In addition, the key drive device 30 for the six keys 31 is connected to the coil 3-
1. It is composed of the minimum four members: an upper yoke 35, a common yoke 36, and an individual yoke 37, and the inclined surfaces 36a and 36b of the common yoke 36 and the individual yokes 37
By setting the inclination angles of the inclined surfaces 37a and 37b to be the same, the upper yoke 3 provided correspondingly
The shape of 5 also becomes a fixed shape, 6 keys 3! The constituent members of the key drive device 30 provided in the key drive device 30 can be made common.

Further, among the above-mentioned constituent members, all three parts other than the coil 34 can be processed by hot extrusion of magnetic metal such as soft iron, so that extremely high productivity can be achieved.

Therefore, the number of inspection items for the structural members is reduced, the work is simplified, and the single common yoke 36
Since it is only necessary to attach the common individual yokes 37 as described above, there is no need to select the assembly position of the individual yokes 37, which facilitates application to automatic machines and improves productivity. .

Furthermore, since the upper yoke 35 is arranged to surround the lower yoke 33 and the individual yokes 37 are arranged in a staggered manner, the magnetic field generated by the coil 34 is Leakage between the drive devices 30 is suppressed, and as shown by solid arrows in FIG. 4, the shortest magnetic circuit is formed and magnetic resistance is reduced.

As a result, the thrust force for the stroke of the upper yoke 3s is
The curve B is smoothed as shown in FIG.
This is significantly larger than the conventional improved technology shown in .

Furthermore, in this embodiment, the heat generated in each coil 34 is transferred from the base plate 40 to the heat transfer plate 39, and further from the heat transfer plate 39 to the heat pipe 41, where the heat is radiated to the outside.

This prevents overheating of the coil 34 and ensures stable operation.

It should be noted that the shapes and dimensions of each component shown in the above embodiments are merely examples, and can be changed in various ways based on design requirements and the like.

For example, the inclination angles of the inclined surfaces 36a, 35b, 37a, and 37b of the common yoke 36 and the individual yokes 37 can be set arbitrarily, and by adjusting the inclination angles, the thrust can be adjusted.

Furthermore, although the upper yoke 35 is shown as an integral structure, it is also possible, for example, to form the central protrusion portion separately and integrate the two using spot welding or the like.

[Effects of the Invention] As explained above, the key drive device for a keyboard instrument according to the present invention includes a lower yoke disposed on a shelf board closer to the player side than the center of assistance of keys of the keyboard instrument; A coil provided on a lower yoke, and an upper yoke disposed on the back side of the key in close opposition to the lower yoke, the lower yoke disposed along the arrangement direction of the keys. It is characterized by consisting of a common yoke and individual yokes arranged in a staggered manner on both sides of the common yoke in the longitudinal direction and around which the coil is wound. l: Effective.

The number of components is reduced by minimizing the number of components, thereby simplifying inspection of the components and improving ease of assembly.

Further, since the individual yokes are arranged in a staggered manner, the influence of adjacent magnetic fields is suppressed to form a magnetic circuit with little leakage, and as a result, the thrust force relative to the stroke of the upper yoke can be significantly improved.

[Brief explanation of drawings]

1 to 4 show an embodiment of the present invention,
Figure 1 is a plan view of the main parts, Figure 2 is a sectional view taken along the line ■-■ in Figure 1, Figure 3 is an exploded perspective view of the main parts, and Figure 4 is for explaining the direction of the magnetic field. An enlarged vertical cross-sectional side view of the main parts of the
FIG. 5 is a characteristic diagram of the thrust force of the key drive device with respect to the stroke of the key, FIGS. 6 and 7 are vertical cross-sectional side views showing the conventional key drive device, and FIGS. 8 and 9 are This shows the key drive device according to the previous application, in which FIG. 8 is a vertical cross-sectional side view of the main part, and FIG. 9 is a cross-sectional view taken along the line ■-■ in FIG. 8. 32...Shelf board, 34...Coil, Coto...Common yoke,

Claims (1)

[Scope of Claims] A lower yoke disposed on a shelf board closer to the player than the center of vibration of the keys of a keyboard instrument; a coil provided on the lower yoke; and a coil disposed on the lower yoke on the back surface of the key. and an upper yoke disposed in close opposition to each other, and the lower yoke includes a common yoke disposed along the direction in which the keys are arranged, and a staggered pattern on both sides of the common yoke in the length direction. A key drive device for a keyboard instrument, comprising: an individual yoke arranged in a shape and around which the coil is wound.