JP2003077362A - Push-button switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To respond to miniaturization needs of a switch as a whole and provide a push-button switch structure which can aim at improvement of soldering strength of a fixed terminal to a conductive pattern. SOLUTION: The switch is provided with a housing 1 equipped with a plurality of fixed contacts 2a, 2b, a movable contact 4 housed in the housing 1 in free contact with and separation from the fixed contacts 2a, 2b and fixed terminals 3a, 3b electrically conducted with the fixed contacts 2a, 2b and protruding toward outside of the housing 1. The fixed terminals 3a, 3b are formed in a linear shape parallel along sidewalls of the housing 1, and the sidewalls of the housing 1 opposing the linear fixed terminals 3a, 3b are provided with a notched part 1b each to be estranged from side face parts of the fixed terminals 3a, 3b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a push button switch in which a movable contact is brought into contact with and separated from a contact when pressed, and more particularly to a structure of a small push button switch used in a portable electronic device or the like.

[0002]

2. Description of the Related Art The structure of a conventional push button switch is shown in FIGS. FIG. 8 is a vertical sectional view of the push button switch, and FIG. 9 is a vertical sectional view showing a mounted state of the push button switch.

The conventional push button switch has a rectangular housing 21 having a housing portion, a central fixed contact 22a and a peripheral fixed contact 22 arranged in the housing portion of the housing 21.
b, the central fixed contact 22a and the peripheral fixed contact 22b
A movable contact 24 that is disposed so as to face upward, and a sheet member 25 that is disposed on the movable contact 24 and covers the storage portion.
And a stem 26 that presses the movable contact 24 through the sheet member 25 to reverse the movable contact 24, and a cover 27 attached to the upper surface of the housing 21.

The housing 21 is formed of an insulating material such as synthetic resin into a rectangular box shape and has a substantially circular storage portion 21a inside. A central fixed contact 22a made of a conductive metal material is provided at the center of the storage portion 21a.
The central fixed contact 2 is arranged so as to be exposed on the inner bottom surface.
Peripheral fixed contacts 22b, which are also made of a conductive metal material, are provided at positions facing each other with the 2a in between. Also,
The peripheral edge of the movable contact 24 and the peripheral fixed contact 22b are electrically connected.

The housing 21 has a pair of linear fixed terminals 23a, 23b protruding outward from the side wall.
Although not shown, the fixed terminals 23a and 23b are embedded in the housing 21 and are electrically connected to the central fixed contact 22a and the peripheral fixed contact 22b, respectively. The pair of fixed terminals 23a and 23b are bent downward along the side wall of the housing 21 to form a soldering terminal having an I terminal shape.

When the stem 26 is pressed, the movable contact 24 is pressed and inverted through the sheet member 25 to come into contact with the central fixed contact 22a and the central fixed contact 22a and the peripheral fixed contact 22b. The fixed terminals 23a and 23b are electrically connected to each other by being connected via the movable contact 24.

When a conventional push button switch is mounted on the circuit board 30, as shown in FIG. 9, the fixed terminals 23a and 23b are placed on a conductive pattern 30a coated with a solder paste such as cream solder. Then, by reflowing, the solder paste is melted and the fixed terminal 23
The solder fillet 31 is fixed by being welded to the outer side surfaces of a and 23b.

[0008]

However, in the structure of the above-mentioned conventional push button switch, when the circuit board 30 is mounted on the circuit board 30 and fixed by soldering, a pair of the fixing terminals to be soldering terminals are provided. The terminals 23a and 23b are
It is bent downward along the side wall of the housing 21, and both have a structure in which only one side of the fixed terminals 23a and 23b is soldered to the conductive pattern 30a.

For this reason, with the recent demand for miniaturization of the entire switch, the width of the soldering terminals has become smaller, so that the soldering range of the terminals becomes smaller and the soldering strength to the conductive pattern 17a becomes smaller. There was a problem that it would be difficult to improve.

Therefore, the present invention solves the above-mentioned problems and responds to the demand for miniaturization of the entire switch, and
An object of the present invention is to provide a push button switch structure capable of improving soldering strength of a fixed terminal to a conductive pattern.

[0011]

In order to solve the above-mentioned problems, according to the present invention, as a first means, a housing in which a plurality of fixed contacts are disposed and a housing housed in the housing and capable of contacting with and separating from the fixed contacts are provided. A movable contact; and a fixed terminal that is electrically connected to the fixed contact and projects to the outside of the housing,
The fixed terminal is formed in a straight line parallel to the side wall of the housing, and the side wall of the housing is spaced apart from the side wall of the housing facing the straight fixed terminal. It is characterized in that a notch portion is formed.

As a second means, the fixed terminal is projected outward from the side wall of the housing, and is linearly bent from the protruding base portion along the side wall of the housing toward the bottom surface. The cutout portion is formed so as to face the free end portion of the fixed terminal and communicate with a bottom surface of the housing from a side wall portion below the protruding base portion.

As a third means, a second cutout portion smaller than the cutout portion is formed on the bottom surface of the housing so as to be continuous with the cutout portion.

As a fourth means, the second notch is formed so as to face a conductive pattern formed on a circuit board to be mounted, and the height of the second notch is reduced. It is characterized in that it is formed so as to have a thickness lower than the coating thickness of the solder paste applied to the conductive pattern.

As a fifth means, the cutout portion is a solder escape portion when the fixed terminal is soldered to a conductive pattern of a circuit board to be mounted, and the second cutout portion is provided. It is a solder relief portion when temporarily fixed on the solder paste.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a push button switch according to the present invention are shown in FIGS. 1 to 4 show an embodiment of the push button switch of the present invention. FIG. 1 is a vertical sectional view of the push button switch, FIG. 2 is a bottom view of the push button switch, and FIG. 3 is a mounting state of the push button switch on a circuit board ( FIG. 4 is a vertical cross-sectional view showing a state before the reflow), and FIG. 4 is a vertical cross-sectional view showing an essential part showing a state where the push button switch is mounted on the circuit board (after the reflow).

1 and 2, the housing 1 is made of an insulating material such as synthetic resin and is formed in a box shape having an opening on the upper surface and having a storage portion 1a inside. A central fixed contact 2a made of a conductive metal terminal material is arranged at the center of the inner bottom surface of the housing portion 1a of the housing 1 in a state of protruding from the terminal material and exposing the upper surface side. Peripheral fixed contacts 2b and 2b, which are also made of a conductive metal terminal material, are disposed at positions facing each other with the central fixed contact 2a interposed therebetween, with the upper surface exposed from the terminal material. Further, fixed terminals 3a and 3b are formed on the opposite outer surfaces of the housing 1 so as to project outward.

The fixed terminals 3a and 3b are connected to the central fixed contact 2a and the peripheral fixed contact 2b in the housing 1 in a conductive state by the terminal material, and the connecting portion is the housing. It is bent within the housing 1 and is embedded in the bottom of the inside of the housing 1.

The fixed terminals 3a, 3b are projected outward from the side wall of the housing 1, and are bent from the protruding base portion along the side wall of the housing 1 toward the bottom surface side so that the fixed terminal 3a, 3b is bent. The fixed terminal 3 is formed in the shape of an I terminal that is a straight line parallel to
Since a and 3b are formed in the I terminal shape, the surface mounting type terminal structure is used by being soldered to the conductive pattern 10a arranged on the upper surface side of the circuit board 10 on which the push button switch is mounted. Has become.

The fixed terminal 3 is provided on the side wall of the housing 1 facing the fixed terminals 3a and 3b which are linear.
A notch 1b is formed to separate the side surfaces of a and 3b from each other. The cutout portion 1b faces the free ends 3c and 3d of the fixed terminals 3a and 3b and faces the housing 1 from the side wall portion below the protruding base portion.
It is formed to communicate with the bottom surface of the.

Further, on the bottom surface side of the housing 1, there are formed locking portions 1c having concave portions at four corners. A locking leg 7b of the cover 7, which will be described later, is engaged with the locking portion 1c.

The movable contact 4 is formed of a conductive metal plate in a substantially disk shape, and has a dome-shaped bulging portion 4a formed at the center, and the lower surface of the top of the bulging portion 4a serves as the central contact portion. Has become. In addition, the peripheral portion of the movable contact 4 has the peripheral fixed contacts 2b, 2b disposed on the inner bottom surface of the housing 1.
It is placed on b and connected to the peripheral fixed contacts 2b and 2b, and the central contact portion is arranged to face the central fixed contact 2a.

The movable contact 4 is inverted by pressing the central dome-shaped bulging portion 4a by a stem 6 which will be described later, so that the central contact portion is connected to the central fixed contact 2a. Has become.

The sheet member 5 is made of a resin sheet material such as polyimide and has a rectangular shape. The seat member 5 has elasticity and is accommodated in the housing portion 1a of the housing 1.
Is attached to the upper surface of so as to cover the movable contact 4.

The stem 6 is made of an insulating material such as synthetic resin. The stem 6 is provided with an operating portion 6a that is pressed, and on the lower surface side of the operating portion 6a,
A pressing projection 6b is formed which projects downward and contacts the upper surface of the bulging portion 4a of the movable contact 4 to press the movable contact 4 downward. Further, a flange portion 6c is formed on the outer peripheral edge of the operation portion 6a so as to contact the inner surface of the cover 7 which will be described later when the stem 6 is pressed.

When the stem 6 is pressed and the stem 6 is returned, the collar portion 6c is moved to the housing 1
The stem 6 is prevented from popping out by being locked to the inner surface of a cover 6 which will be described later and which is fixed to the upper surface side.

The cover 7 is made of a plate material such as a metal plate and is formed in a substantially rectangular box shape. The cover 7 is provided at its center with an insertion hole 7a through which the operation portion 6a of the stem 6 is projected, and at the four lower corners, the locking formed on the lower surface side of the housing 1 is provided. A locking leg 7b engaged with the portion 1c is formed. This locking leg 7
The cover 7 is fixed to the upper surface of the housing 1 by engaging b with the locking portion 1c of the housing 1 and caulking by a method such as pressing.

Next, the operation of the push button switch having the above structure will be described. As shown in FIG. 1, when the stem 6 is in the non-pressing operation state, the peripheral edge of the movable contact 4 is in contact with the upper surfaces of the peripheral fixed contacts 2b and 2b, but the dome-shaped bulging portion 4a. Is separated from the central fixed contact 4a, and the switch is off.

From this state, when the stem 6 is pressed with a finger or the like, the pressing protrusion 6b provided below the operating portion 6a of the stem 6 causes the movable contact 4 to pass through the sheet member 5. The upper surface of the bulging portion 4a is pressed to push down the bulging portion 4a.

At this time, the bulging portion 4a of the movable contact 4 is pressed downward, whereby the bulging portion 4a of the movable contact 4 is inverted downward. Therefore, the lower surface of the top of the bulging portion 4a comes into contact with the central fixed contact 2a, the peripheral fixed contacts 2b and 2b are electrically connected to the central fixed contact 2a, and the switch is turned on.

When the pressing force on the stem 6 is released from this state, the bulging portion 4a of the movable contact 4 is reversed by its own elasticity to return to the initial state, and at the same time, the urging force is applied. The stem 6 is pushed upward and returns to the initial position. At this time, as the bulging portion 4a is reversed, the lower surface of the top of the bulging portion 4a is separated from the central fixed contact 2a, and the switch is turned off.

Next, the mounting state of the push button switch having the above-mentioned configuration on the circuit board will be described. FIG. 3 shows a state before the reflow, in which the conductive pattern 1 of the circuit board 10 is shown.
0a is solder paste 11 made of cream solder or the like.
Has been applied. Then, the free ends 3c and 3d of the fixed terminals 3a and 3b formed in the housing 1 and having the I terminal are placed on the solder paste 11. In this case, the solder paste 11 is applied on the conductive pattern 10a so as to be located in the cutout portion 1b of the housing 1.

From this state, when the push button switch is soldered by passing it through a solder reflow oven, the solder paste 11 is melted and fixed (welded) by the heat of the reflow oven as shown in FIG. As a result, the solder fillet 12 is formed. In this case, the solder fillet 12 is also formed in the cutout portion 1b, and is formed over both side surface portions of the fixed terminals 3a, 3b.

According to the above construction, by forming the cutout portion 1b on the side wall of the housing 1, the free ends 3c of the fixed terminals 3a, 3b facing the side wall,
Since the side surface portion on the 3d side is separated from the side wall of the housing 1 and a solder escape portion is formed when soldering to the housing 1, the housing 1 is mounted on the circuit board 10. In this case, it becomes possible to solder to both side surfaces of the fixed terminals 3a and 3b having the linear I terminal shape, and the soldering strength can be improved.

Further, the fixed terminals 3a, 3b are projected outward from the side wall of the housing 1, and are linearly bent from the protruding base portion along the side wall of the housing 1 toward the bottom surface side, The cutout portion 1b faces the free ends 3c and 3d of the fixed terminals 3a and 3b and faces the housing 1 from the side wall portion below the protruding base portion.
The fixed terminals 3a and 3b can be bent by using the side wall of the housing 1 and can be bent at the same time because they are formed so as to communicate with the bottom surface of the fixed terminals 3a and 3b.
It becomes possible to solder to both side surfaces of the fixed terminals 3a and 3b having a linear I terminal shape without increasing the width of the entire housing 1 including the above, and the soldering strength at the time of soldering is improved. It has become possible.

5 to 7 show another embodiment of the present invention. FIG. 5 is a vertical sectional view of a push button switch, and FIG. 6 is a vertical sectional view showing a mounting state of the push button switch on a circuit board (before reflow). FIG. 7 is a longitudinal cross-sectional view of a main part showing a mounted state (after reflow) of the push button switch on the circuit board. 1 to 4
The same parts described in 1 are assigned the same reference numerals and explanations thereof are omitted.

The difference between the structure of this embodiment and the first embodiment is that the structure of the cutout portion 1b is partly different. That is, in the present embodiment, the second cutout portion 1d, which is smaller than the cutout portion 1b and is continuous with the cutout portion 1b, is formed on the bottom surface of the housing 1. By providing the second cutout portion 1d, the switch can be temporarily fixed to the solder paste 11 at the time of mounting on the circuit board 10.

In this case, the second cutout portion 1d is
It is formed on the bottom surface side of the housing 1 so as to be continuous with the cutout portion 1b, and the second cutout portion 1 is formed.
d is formed so as to face the conductive pattern 10a formed on the circuit board 10 to be mounted, and the height H of the second cutout portion 1d is the conductive pattern 1
It is formed so as to have a thickness smaller than the coating thickness M of the solder paste 11 applied to 0a. (H <M)

In this embodiment, the second cutout portion 1 is used.
The height H of d is set to 0.02 to 0.08 mm, and the coating thickness M of the solder paste 11 is set to a range of 0.1 to 0.15 mm. According to this numerical value, when the push button switch is mounted on the circuit board 10, the push button switch before reflow can be optimally fixed temporarily.

Next, the mounting state of the push button switch having the above-mentioned configuration on the circuit board will be described. FIG. 6 shows a state before the reflow, in which the conductive pattern 1 of the circuit board 10 is shown.
0a is solder paste 11 made of cream solder or the like.
Has been applied. Then, the free ends 3c and 3d of the fixed terminals 3a and 3b formed in the housing 1 and having the I terminal are placed on the solder paste 11. In this case, the solder paste 11 is applied on the conductive pattern 10a so as to be located in the cutout portion 1b of the housing 1 and the second cutout portion 1d.

When the housing 1 is placed on the circuit board 10, the height H of the second cutout portion 1d is lower than the coating thickness M of the solder paste 11 (M>
H) Since it is formed, the cream-like solder paste 11 is pressed and deformed by the top surface of the second cutout portion 1d. At this time, the solder paste 11
Is in a state of being filled in the second cutout portion 1d, and is positioned by the adhesive force of the filled solder paste 11, and the housing 1 is electrically conductive to which the solder paste 11 is applied. It is temporarily fixed on the pattern 10a.

From this state, when the push button switch is soldered by passing it through a solder reflow furnace, the solder paste 11 is melted and fixed (welded) by the heat of the reflow furnace as shown in FIG. As a result, the solder fillet 12 is formed. In this case, the solder fillet 12 is also formed in the cutout portion 1b, and is formed over both side surface portions of the fixed terminals 3a, 3b.

According to the above structure, the housing 1 is continuously connected to the cutout portion 1b which is a solder escape portion when the fixed terminals 3a and 3b are soldered to the conductive pattern 10a of the circuit board 10. The second cutout portion 1 which is a solder escape portion when temporarily fixed onto the solder paste 11.
When the push button switch is mounted on the circuit board 10 by forming d, the second cutout portion 1d is filled with the solder paste 11 and positioned so that the solder paste 11 is positioned on the solder paste 11. The push button switch can easily be temporarily fixed to the device, and it is prevented from floating during transportation into the apparatus during reflow, and can be reliably soldered to both side portions of the fixed terminals 3a and 3b.

[0044]

As described above, the push button switch of the present invention has a housing in which a plurality of fixed contacts are arranged, a movable contact housed in the housing and capable of coming into contact with and separating from the fixed contacts, and conducting with the fixed contacts. The fixed terminal is formed in a straight line parallel to the side wall of the housing, and the fixed terminal is provided on the side wall of the housing facing the straight fixed terminal. Since the notch is formed to separate the side terminal of the fixed terminal from the side surface of the fixed terminal, the side surface of the fixed terminal facing the side wall is separated from the side wall of the housing, and the solder escape portion when soldering to the housing is formed. Since it is formed, when the housing is mounted on the circuit board, it becomes possible to solder to both side surfaces of the fixed terminal having a linear I-terminal shape, and the soldering strength can be improved. Kill.

Further, the fixed terminal is projected outward from the side wall of the housing, and is linearly bent from the protruding base portion along the side wall of the housing toward the bottom surface side, and the cutout portion of the fixed terminal is formed. The fixed terminal can be bent by using the side wall of the housing and can be bent using the side wall of the housing since the side wall portion below the projecting base portion and the bottom surface of the housing communicate with each other so as to face the free end portion. It is possible to solder to both side surfaces of the fixed terminal having a linear I-terminal shape without increasing the overall width, and the soldering strength at the time of soldering can be improved.

Further, since the second cutout portion, which is smaller than the cutout portion and is continuous with the cutout portion, is formed on the bottom surface of the housing, when the push button switch is mounted on the circuit board, the second cutout portion is formed. Since the notch part is positioned with the solder paste filled in, it is easy to temporarily fix the push button switch on the solder paste, and it is prevented from floating during transfer into the device during reflow and is securely fixed. It can be soldered to both sides of the terminal.

Further, the second cutout portion is formed so as to face the conductive pattern formed on the circuit board to be mounted,
Since the height of the second cutout portion is formed to be lower than the coating thickness of the solder paste applied to the conductive pattern, when the pushbutton switch is mounted on the circuit board, The temporary fixing can be optimally performed.

Further, the cutout portion is a solder escape portion when the fixed terminal is soldered to the conductive pattern of the circuit board to be mounted, and the second cutout portion is temporarily fixed on the solder paste. Since it is the solder relief portion, the push button switch can be temporarily fixed before the reflow and soldered to the fixed contact after the reflow with a simple structure.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a push button switch according to an embodiment of the present invention.

FIG. 2 is a bottom view showing the same push button switch of the present invention.

FIG. 3 is a longitudinal sectional view showing a mounting state (before reflow) of the push button switch of the present invention on a circuit board.

FIG. 4 is a vertical cross-sectional view of a principal portion showing a mounting state (after reflow) of the push button switch of the present invention on a circuit board.

FIG. 5 is a vertical sectional view showing a push button switch according to another embodiment of the present invention.

FIG. 6 is a longitudinal sectional view showing a mounting state (before reflow) of the push button switch of the present invention on a circuit board.

FIG. 7 is a longitudinal cross-sectional view of relevant parts showing a state where the push button switch of the present invention is similarly mounted on the circuit board (after reflow).

FIG. 8 is a vertical sectional view showing a conventional push button switch.

FIG. 9 is a vertical cross-sectional view showing a mounting state of a conventional push button switch on a circuit board.

[Explanation of symbols]

1 housing 1a Storage section 1b Notch 1c Locking part 1d second notch 2a Central fixed contact 2b Peripheral fixed contact 3a, 3b fixed terminal 3c, 3d free end 4 movable contacts 4a bulge 5 sheet members 6 stems 6a Operation part 6b Pressing protrusion 6c Tsuba 7 cover 7a insertion hole 7b Locking leg 10 circuit board 10a conductive pattern 11 Solder paste 12 Solder fillet H second cutout height M Solder paste application thickness

Claims (5)

[Claims] 1. A housing in which a plurality of fixed contacts are disposed, a movable contact housed in the housing and capable of coming into contact with and separating from the fixed contacts, and a fixed terminal which is electrically connected to the fixed contacts and projects to the outside of the housing. And the fixed terminal,
A linear notch is formed along the side wall of the housing, and a notch is formed on the side wall of the housing facing the linear fixed terminal so as to be separated from the side surface of the fixed terminal. A push button switch characterized by the above. 2. The fixed terminal is projected outward from a side wall of the housing, is linearly bent from the protruding base portion along the side wall of the housing toward the bottom surface, and the cutout portion is formed. 2. The push button switch according to claim 1, wherein the push button switch is formed so as to face the free end portion of the fixed terminal and communicate with the bottom surface of the housing from a side wall portion below the protruding base portion. 3. The push button switch according to claim 2, wherein a second cutout portion which is continuous with the cutout portion and is smaller than the cutout portion is formed on the bottom surface of the housing. 4. The second cutout portion is formed so as to face a conductive pattern formed on a circuit board to be mounted,
4. The push button switch according to claim 3, wherein the height of the second cutout portion is formed to be lower than the coating thickness of the solder paste applied to the conductive pattern. 5. The cutout portion is a solder escape portion when the fixed terminal is soldered to a conductive pattern of a circuit board to be mounted, and the second cutout portion is temporarily placed on a solder paste. The push button switch according to claim 3, wherein the push button switch is a solder relief portion for fixing.