JPH1012086A - Key switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain key operability with good assembling workability and click sense by providing a columnar protrusion portion for a rubber spring, forming a thickness portion around an outer circumference, and pressing in a cylindrical stem of a key top. SOLUTION: A key top 1 is provided with a cylindrical stem 1b, and a dome- shaped rubber spring 8 to be pressed by means of this stem 1b is provided. This rubber spring 8 is provided with a protrusion portion 8a protruded and formed in a columnar on a top thereof, and two or more thickness portions 8b are formed around an axial outer circumference of the protrusion portion 8a and pressed in the cylindrical stem 1b of the key top 1. When this key top 1 is pressed downward, a tip end of the stem 1b presses down a press face 8c of the spring 8. Therefore, a upper portion of a support wall 8d of the dome- shaped inside is a flat face identical to a ceiling face 8e, further is deformed, and shaped in a reverse-L-letter. At this time, an actuation force to be applied to the key top 1 is acutely decreased, and further the pressed down protrusion 8f presses a switch contact of a sheet switch 4. Thus, good operability and assembling workability are obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a key switch used in a keyboard device used for inputting a signal to an electronic device or the like.

[0002]

2. Description of the Related Art Key switches of this type are widely used for data input of input devices such as personal computers and word processors. In recent years, demands for delicate operation feelings have increased in order to improve operability. ing. Hereinafter, with respect to a conventional key switch, as shown in FIGS. 8 to 11, the key top 1 is a key top upper surface 1a pressed by an operator.
On the back side, a cylindrical stem 1b having an inner diameter A is integrally formed. A plurality of stem supporting portions 2a are formed in a housing 2 supporting the key top 1 so as to protrude and have a hollow inside. A stem guide hole 2b is formed at the center of the protruded stem support portion 2a, and the stem 1b of the key top 1 is inserted into the stem guide hole 2b and supported so as to be vertically movable. I have.

A dome-shaped rubber spring 3 is inserted inside the hollow of the stem support 2a. A cylindrical protrusion 3a having an outer diameter B is formed on the top of the rubber spring 3. The protruding portion 3a is inserted with a gap T into the cylindrical inner diameter A of the stem 1b. At this time, the inner diameter A of the stem 1b and the outer diameter B of the protruding portion 3a have a relationship of A> B. A flat pressing surface 3b pressed by the tip of the stem 1b is formed around the protruding portion 3a. The inside of the dome shape of the rubber spring 3 has a support wall 3c and an upper surface formed by a ceiling surface 3d.
At approximately the center of d, a projection 3e is provided downward. On the lower surface of the housing 2, a sheet-like switch 4 composed of a membrane switch or the like is arranged, and the switch contact of the sheet-like switch 4 and the projection 3e are arranged to face each other. A lower plate 5 such as a metal plate is formed on the lower surface of the switch 4.
A key switch is configured by mounting the respective components.

In the key switch configured as described above, the stem 1b is supported by the stem guide hole 2b of the housing 2, and the key top 1 is pressed down by an operator's pressing operation. At this time, the tip of the stem 1b presses the pressing surface 3b of the rubber spring 3 to deflect the support wall 3c of the rubber spring 3, and the dome-shaped ceiling surface 3d
When the projection 3e is pushed down to the sheet-like switch 4 side, as shown in FIG. 9, a part of the support wall 3c whose inside is formed in a dome shape becomes flush with the ceiling surface 3d. From this state, when the key top 1 is further depressed,
The support wall 3c is deformed downward, and the load applied to the key top 1 is suddenly reduced by the reversing operation. Then, the key top 1 is further pushed down by the inertia of the load applied to the key top 1. When the key top 1 is further depressed, a restoring force is exerted on the support wall 3c of the rubber spring 3 to return to the initial dome shape. Then, the pressing surface 3b pressed by the tip of the stem 1b is pulled outward, and the root of the protruding portion 3a is also pulled outward.

For this purpose, the dimension B of the root of the protruding portion 3a expands to B1, and the tip of the stem 1b and the pressing surface 3b
Slip occurs between the two. However, since the rubber spring 3 is made of rubber as described above, the frictional resistance is large.
Due to the frictional resistance of the pressing surface 3b pressed against the tip of the stem 1b, the operating force of the keytop 1 increases before the projection 3e of the keytop 1 contacts the sheet-like switch 4. From this state, a load is further applied to the key top 1 and the key top 1 is pressed down, and the projection 3e presses the switch contact of the sheet-like switch 4 to turn on the switch.

The change in the operating force as described above will be described with reference to an operating force curve shown in FIG. 11. From the point O where the operating force on the key top 1 is unloaded, a load is applied and the key top 1 is pushed down. Then, the operating force curve becomes an upward curve by the elastic force of the rubber spring. Then, when the key top 1 is further pressed down after reaching the operating force peak point G, the operating force suddenly decreases due to the reversal operation of the rubber spring 3 described above, and the operating force curve changes downward. The key top 1 moves from the operating force peak point G to the operating force bottom point J due to the inertial force of the operating force applied to the key top 1 until now. However, at this point, the tip of the stem 1b and the pressing portion 3b of the rubber spring
When the key top 1 passes the operating force bottom point J when the frictional resistance is generated, the operating force becomes heavy, the operating force curve turns upward, and the end point H of the full stroke amount of the key top 1 is increased.
In 2, the projection 3e presses the switch contact of the sheet-like switch 4 to turn on the switch.

Normally, in a key switch used in a keyboard device, a stroke feeling and a click feeling are felt by an operator, and are used as a guide for determining whether or not the sheet-like switch 4 is turned on. The click feeling and the stroke feeling will be described with reference to the operating force curve of FIG. 11, and the change width Y2 of the operating force from the operating force peak point G to the bottom point J is referred to as the click feeling. Further, the key top movement amount S2 from the actuation force peak point G to the bottom point J is called a stroke feeling. And in these key switches,
The key switch having a good feeling is that the actuation force bottom point J and the end point H2 of the total stroke amount are the same point, and the movement amount S2 of the key top 1 for which a stroke feeling is felt.
It is desirable that the change width Y2 of the actuation force for feeling the click feeling be within a predetermined range.

However, in a conventional key switch,
The switch is not turned on even after the operating force bottom point J, which is the end point of the click feeling and the stroke feeling, and the operating force must be applied to the key top 1 again to push the key top 1 further downward to move it. If the switch was not turned on. Therefore, when the operator feels the operating force bottom point J, and when the operating force curve turns upward and the operating force becomes heavy, the operating force bottom point J is mistaken for the end point H2 of the total stroke amount S. There was something to do. Therefore, at the position of the operating force bottom point J, the operator may release the pressing of the key top 1 and do not press the key top 1 until the end point H2 of the total stroke amount S, and an input error may occur. there were. Further, after the operating force peak point G, the operating force is suddenly reduced by the reversing operation of the rubber spring 3 and the switch is not turned on even when the operating force curve reaches the bottom point J. Feeling was bad because it had to be pushed to the end point H2 of the total stroke amount S.

[0009]

In a conventional key switch, a load is applied to the key top 1 and the key top is depressed downward so that the operator can feel a click feeling and a stroke feeling.
Even if the operating force reaches the operating force bottom point J, the switch
Since N is not applied, the key top 1 must be further moved to the end point H2 of the total stroke amount S by applying a load, so that the operability and feeling of the key top 1 are poor. For this reason, there is a problem that an input error occurs due to an operation error of the operator. Also, in order to eliminate the input error, the operator looks at the display while pressing the key top 1.
Was pressed to check whether the switch contact of the sheet-like switch 4 was correctly turned on. Therefore, there is a problem that the efficiency of the key switch operation is low.

[0010]

As a first means for solving the above-mentioned problems, a key switch according to the present invention comprises a tubular stem provided on a key top and a dome-shaped stem pressed by the stem. A rubber spring; and a protrusion formed in a columnar shape on the top of the rubber spring, and at least three or more build-up portions are formed on the outer periphery of the protrusion in the axial direction to form the build-up portion. The projected portion was press-fitted to the stem, and the key top and the rubber spring were attached. Further, as a second means for solving the above-described problem, the protrusion of the rubber spring has a configuration having a flesh portion.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a key switch according to the present invention will be described below. First, as shown in FIG. 1, a keyboard device using the key switch of the present invention has a plurality of key tops 1 mounted on a housing 2 and a sheet-like switch 4 disposed below the housing 2. And a lower plate 5 on which the switch 4 is mounted. The housing 2 and the lower plate 5 sandwiching the sheet-like switch 4 are integrated into a housing 6, and the housing 2 is mounted on the housing 6. The body 7 is closed by exposing the key top 1 and closing the lid.
Are screwed (not shown) to form a keyboard device.

As shown in FIGS. 2 to 7, the key switch 1 of the present invention used in such a keyboard device has a key top 1 made of synthetic resin and the surface thereof is pressed by an operator's finger or the like. An upper surface 1a to be formed and a tubular stem 1b having a hollow inside are integrally formed on the back side. The inner diameter of the stem 1b is formed to have a dimension A. The housing 2 supporting the key top 1 is made of synthetic resin.
A plurality of stem support portions 2a are formed so as to protrude in a truncated cone shape. The stem support portion 2a has a hollow inside, and a stem guide hole 2b is formed in the ceiling surface of the hollow. The stem 1b of the key top 1 is inserted into the stem guide hole 2b, and the key top 1 moves up and down. It is freely supported.
The stem support portions 2a are provided corresponding to the number of key switches of the keyboard device.

Further, a rubber spring 8 made of elastic rubber having a dome shape is inserted in the hollow inside of the stem support portion 2a. As shown in FIGS. 2 to 4, the rubber spring 8 has a flesh portion outside the top portion up to the center portion.
It has a built-up portion 8b on its outer periphery and is provided so as to protrude upward. The overlaid portion 8b is formed on the outer periphery of the protruding portion 8a in the direction of the axis X at least two or more, for example, divided into three equal parts at three places in the present embodiment.
The outer diameter of the protruding portion 8a including the built-up portion 8b is formed with a dimension C. The outer dimension C has a relationship of A <C with the inner diameter dimension A of the stem 1b.
For this purpose, the outer diameter of the protruding portion 8a including the built-up portion 8b of the rubber spring 8 is press-fitted to the inner diameter of the stem 1b. A pressing surface 8c is formed flat around the base of the protruding portion 8a so that the tip of the stem 1b of the key top 1 presses the rubber spring 8.

The inside of the rubber spring 8 is formed in a dome shape with a supporting wall 8d on the periphery and a ceiling surface 8e on the upper surface. At a substantially central portion of the ceiling surface 8e, a conical projection 8f is provided downward with a predetermined length. On the lower surface of the housing 2 in which the rubber spring 8 is inserted, electrodes are provided on the upper sheet and the lower sheet, and the upper sheet is locally pressed by the projection 8f of the rubber spring 8 toward the lower sheet. And a sheet-like switch 4 including a membrane switch or the like, which has a switching function of conducting the upper and lower electrodes. Further, a lower plate 5 made of a metal plate or the like is placed on the lower surface side of the sheet-like switch 4 on which the above-mentioned components are mounted, thereby constituting a key switch of the present invention.

In the key switch of the present invention having the above-described structure, when the key top 1 is depressed downward, the stem 1b press-fits the protrusion 8a having the overlaid portion 8b.
The operating force is increased by the elastic force of the rubber spring 8 while the tip of the rubber spring 8 pushes down the pressing surface 8c of the rubber spring 8 and deflects the support wall 8d. As shown in FIG. 5, the state of the rubber spring 8 when the operating force for pushing down the key top 1 is at its peak is such that the upper part of the support wall 8d in the dome shape is flush with the ceiling surface 8e. This figure 5
When the key top 1 is further depressed from the state shown in FIG. 6, the cross section of the support wall 8d is rapidly deformed as shown in FIG.
The key top 1 is turned into a letter shape, and the reversing operation is performed, so that the operating force applied to the key top 1 is rapidly reduced. The key top 1 is further pushed down by the inertial force of the operating force applied to the key top 1 so far, and the projection 8f presses the switch contact of the sheet-like switch 4 to turn on the switch. .

Referring to FIG. 7, the change of the operating force curve of the key switch will be described. The operating force of the key top 1 is applied from the point O where no load is applied to the key top 1 and the key top 1 is depressed. Then, the operating force curve rises upward, and the operating force reaches the peak point G. At this time, in the state of the rubber spring 8, as shown in FIG. 5, the upper part of the side wall 8d forms the same plane as the ceiling surface 8c. When the key top 1 is further depressed from this state, the operating force suddenly decreases due to the reversal operation of the rubber spring 8 described above, and the operating force curve changes downward. Then, the key top 1 moves to the end point H1 of the entire stroke amount S while the operating force is reduced from the operating force peak point G by the inertia force of the operating force applied to the key top 1 so far, and the protrusion 8f
When the switch presses the switch contact of the sheet-like switch 5, the key top 1 cannot move any more, so that the operating force curve rises vertically from the end point H1 of the full stroke amount S,
The load suddenly increases, and the movement of the key top 1 stops at the end point H1 of the entire stroke S.

At this time, a restoring force acting to return to the initial dome shape is applied to the rubber spring 8 to apply a force for pulling the pressing surface 8c outward. 1b, the frictional resistance between the distal end of the stem 1b and the pressing surface 8c does not occur unlike the related art. Therefore, the end point H1 of the total stroke amount S of the key switch of the present invention, the end point of the stroke feeling S1, which is the bottom point of the operating force, and the end point of the click feeling Y1 become the same position, and the operator switches the sheet-like switch 4 It is possible to reliably feel that the switch contact is turned ON.

[0018]

As described above, according to the key switch of the present invention, at least two or more build-up portions are formed on the axially outer periphery of the protrusion of the rubber spring, and the build-up portions are formed. Since the formed protrusion is press-fitted into the stem and the key top and the rubber spring are attached, the end point of the total stroke amount S, the end point of the stroke feeling, and the end point of the click feeling are the same. Because
A key switch with good feeling and good operability can be provided. Also, at least two or more overlaid portions are formed on the outer periphery in the axial direction of the protrusion of the rubber spring, and the stem is formed on the stem. Since the fitting area is press-fitted, the contact area between the protruding portion and the inner diameter of the stem is small, so that the press-fitting can be performed with a small force. Also, since the protrusion of the rubber spring has a flesh portion up to the center, even if the protrusion is pressed into the inner diameter of the stem, the inside of the protrusion is clogged with the flesh to the center, so the protrusion is Since the key top is pressed into the stem without being deformed, the key top and the rubber spring can be easily pressed in, and a key switch in which the pressed-in key top is difficult to come off can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a keyboard device using a key switch of the present invention.

FIG. 2 is a cross-sectional view of an essential part showing an initial state of the key switch of the present invention.

FIG. 3 is a front view of the rubber spring of the present invention.

FIG. 4 is a top view of the rubber spring of the present invention.

FIG. 5 is a sectional view of a main part showing an operation state of the key switch of the present invention.

FIG. 6 is a sectional view of a key part showing an operation state of the key switch of the present invention.

FIG. 7 is a graph of an operating force curve of the key switch of the present invention.

FIG. 8 is a sectional view of a main part showing an initial state of a conventional key switch.

FIG. 9 is a sectional view of a main part showing an operation state of a conventional key switch.

FIG. 10 is a sectional view of a main part showing an operation state of a conventional key switch.

FIG. 11 is a graph of an operating force curve of a conventional key switch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Key top 1a Top surface 1b Stem 2 Housing 2a Stem support part 2b Stem guide hole 3 Rubber spring 3a Projection part 3b Press surface 3c Support wall 3d Ceiling surface 3e Projection 4 Sheet switch 5 Lower plate 6 Housing 7 Housing 8 Rubber spring 8a Projecting portion 8b Filling portion 8c Pressing surface 8d Support wall 8e Ceiling surface 8f Projection

Claims (2)

[Claims] 1. A cylindrical stem provided on a key top, a dome-shaped rubber spring pressed by the stem, and a projection formed in a column shape on the top of the rubber spring. At least two or more built-up portions were formed on the outer periphery in the axial direction, and the projections formed with the built-up portions were press-fitted to the stem to attach the key top and the rubber spring. A key switch, characterized in that: 2. The key switch according to claim 1, wherein the protruding portion of the rubber spring has a thick portion up to a center portion.