JP5382446B2 - pressure switch - Google Patents

Description

  The present invention relates to a pressure switch that switches by opening and closing a contact portion that is linked to a diaphragm that responds to a pressure change.

  As the pressure switch, for example, there is a negative pressure switch that outputs a switch signal for alarming a pressure drop in the tank when the vehicle braking pressure tank (vacuum tank) drops below a predetermined pressure.

FIG. 16 is a cross-sectional view showing an example of this type of negative pressure switch.
As shown in the figure, this negative pressure switch is composed of a metallic body 11 having a threaded portion 11a that is screwed into a predetermined position of a vacuum tank, and an electrically insulating terminal that is crimped to the body 11 and integrated. And a base 12.
The vacuum tank is a tank that stores a pressure necessary for operating the brake of the vehicle.

A disc-shaped diaphragm 13 made of a flexible material such as rubber is disposed in an internal space formed by the body 11 and the terminal base 12. The internal space is separated from the pressure chamber 14 by the diaphragm 13. The operation room 15 is divided into two.
A movable contact 16 and a spring receiver 17 are integrally fixed to the diaphragm 13 at the center thereof.

That is, the movable contact 16 is switched to and from the fixed contact 18 according to the variation of the diaphragm 13.
The fixed contact 18 is provided in a terminal 19 embedded in the terminal base 12, and the terminal 19 is connected to a vacuum tank pressure drop alarm circuit via a cord.

The spring receiver 17 receives a coil spring 21 between the spring receiver 17 and the adjusting screw 20 screwed into the body 11.
That is, the adjustment screw 20 is turned to adjust the spring force of the coil spring 21 so that the movable contact 16 is pressed against the fixed contact 18.
The adjusting screw 20 is formed of a metallic material, and is provided with a communication hole 20a.

On the other hand, the terminal base 12 is provided with a vent hole 22 for communicating the operating chamber 15 and the atmospheric pressure so as to keep the operating chamber 15 at the atmospheric pressure.
As shown in the figure, the vent hole 22 is formed in a T-shape having a pore shape, and one end side of the vertical hole portion 22a passes through a hole portion formed in the fixed contact 18 to the operation chamber 15, and the other end side is a horizontal hole portion. 22b communicates with each other.
The vent hole 22 is used to keep the operating chamber 15 at atmospheric pressure. When the diaphragm 13 is sucked to the pressure chamber 14 side by a negative pressure, the operating chamber 15 is prevented from approaching a vacuum, and is set to a negative pressure. The switch is surely operated according to the pressure.

  The side surfaces of the terminal base 12 are provided with flat portions 23 and 24 formed in contrast, and the horizontal hole portion 22b described above is provided between the flat surface portions 23 and 24, and one of the horizontal hole portions 22b is provided. The hole openings 22b1 and 22b2 are located on the plane part 23, and the other hole opening is located on the plane part 24.

Further, ventilation sheets 25 and 26 are bonded to the flat portions 23 and 24 where the hole openings 22b1 and 22b2 are located, and the hole openings 22b1 and 22b2 are covered with the ventilation sheets 25 and 26.
The ventilation sheets 25 and 26 are ventilation sheets that allow only gas to pass and prevent the passage of a solution (for example, water), and prevent water from entering the ventilation holes 22.
The ventilation sheets 25 and 26 are fixed to the flat portions 23 and 24 by a sticking means.
A cylindrical cover 27 is attached to the terminal base 12.
A concave groove 27a is provided on the inner surface of the cover 27 to prevent water from staying.

In the negative pressure switch described above, when a predetermined negative pressure is not applied to the pressure chamber 14, the movable contact 16 receives the spring force of the coil spring 21 and comes into contact with the fixed contact 18, so that the switch is in an ON state.
That is, the signal path of the terminal 19, the fixed contact 18, the movable contact 16, the spring receiver 17, the coil spring 21, the adjusting screw 20, and the body 11 is formed, and a switch ON signal is sent to the vacuum tank pressure drop alarm circuit.

When a predetermined negative pressure is applied to the pressure chamber 14, the diaphragm 13 is attracted to the adjusting screw 20 against the spring force of the coil spring 21, and in conjunction with this, the movable contact 16 is separated from the fixed contact 18, and the switch is turned off. It becomes.
As a result, the signal path is interrupted, and a switch OFF signal is sent to the vacuum tank pressure drop alarm circuit.

In the negative pressure switch described above, water such as cleaning water is received by the cover 27, and the cleaning sheets do not directly hit the ventilation sheets 25 and 26.
In addition, the water staying between the ventilation sheets 25 and 26 and the cover 27 flows out of the cover through the space formed by the concave groove 27a.

On the other hand, a positive pressure switch configured in substantially the same manner as the negative pressure switch described above is known.
This positive pressure switch has a diaphragm that does not fluctuate when a pressure higher than a predetermined pressure is not applied to the pressure chamber, the movable contact is in contact with the fixed contact, and the switch is ON.
Further, when a pressure higher than a predetermined pressure is applied to the pressure chamber, the diaphragm fluctuates, and the movable contact linked to the fluctuation is separated from the fixed contact, and the switch is turned off.
The positive pressure switch as described above is used as, for example, a pressure switch for detecting the oil pressure of a vehicle engine.

JP 2000-195395 A

  The above-described conventional negative pressure switch is configured to prevent the ventilation hole 22 from being flooded by the ventilation sheets 25 and 26. However, the ventilation sheets 25 and 26 are bonded using a double-sided adhesive tape or an adhesive. Therefore, it may be easily peeled off.

Further, when a cap is provided so as to hold the vent sheet, the cap is fixed in a direction in which the cap is pressed against the switch housing and the vent sheet is sandwiched. Therefore, high accuracy is required for the size of the abutting surface of the cap with respect to the vent sheet.
That is, if the pressing force of the cap is insufficient, the ventilation sheet floats up. Conversely, if the pressing force is too strong, the ventilation sheet may be broken.

  On the other hand, in the case of a pressure switch that detects the oil pressure of a vehicle engine, if a crack or the like occurs in the diaphragm, oil may flow into the switch from the crack, and in such a case, the ventilation sheet floats or breaks. Otherwise, there was a risk that the oil would flow out of the switch through the air vent and the engine could burn out.

  Therefore, in the present invention, in view of the above-described circumstances, there is no fear of the ventilation sheet being lifted or torn, it is possible to ensure the arrangement of the ventilation sheet, prevent water from entering the ventilation holes, or the pressure switch diaphragm is torn. Accordingly, an object of the present invention is to propose a pressure switch that prevents the ventilation sheet from peeling and lifting even when oil flows into the switch and prevents oil from flowing out from the ventilation hole.

In order to achieve the above-described object, in the present invention, as a first invention, a diaphragm is disposed in an internal space formed between the body and the terminal base, and the operation space, the pressure chamber, and the internal space are separated by the diaphragm. In a pressure switch having a contact portion that opens and closes in conjunction with a diaphragm that responds to a pressure change in the pressure chamber.
The terminal base is provided with a receiving hole provided at a target position centered on a vent hole formed in the periphery of the terminal base and communicating with the operation chamber, and a vent hole of the vent hole located in the recess position. Each of the locking receiving portions at the target position is formed of a groove portion provided along an outer circle of the hole opening and a locking portion communicating with the groove portion, and A two-arm cover having arm portions that are formed so as to protrude from the target position of the cover portion in accordance with each of the stopper portions, each arm portion having a locking projection, and a recessed portion of the terminal base. A vent sheet that prevents water from entering the hole, sandwiching the vent sheet between the recessed portion of the terminal base and the two-arm cover, and the arm portion of the two-arm cover in the groove portion of the locking receiving portion After insertion, by rotating the two-arm cover, Suggest pressure switch, characterized in that the stop projection has a structure for securing the locked allowed to 2 arm cover locking portion of the latch receiving portion on a terminal base.

  As a second invention, in the pressure switch of the first invention described above, the groove portion of the locking receiving portion is a passage portion of a locking protrusion provided on the two-arm cover, and the locking portion of the locking receiving portion Proposes a pressure switch characterized in that it is formed as a stopper for preventing the locking projection provided on the two-arm cover from coming out and returning.

  As a third invention, in the pressure switch of the first or second invention described above, the two-arm cover is provided with a pressing portion made of a substantially circular rib provided with a discontinuous portion, and the two-arm cover is connected to the terminal. A pressure switch is proposed in which the ventilation sheet is pressed by the pressing portion by being fixed to the base, and the non-continuous portion of the pressing portion becomes an air circulation portion.

The pressure switch according to the present invention is provided with a two-arm cover that sandwiches a vent sheet that covers a vent hole located in a concave portion formed around the terminal base and is sandwiched between the two-arm cover. With respect to the above, since it is configured to be rotated and locked with respect to the locking receiving portion provided in the recessed portion, the pressing force of the ventilation sheet does not become excessive or insufficient. Will not lift or tear.
Further, since the two-arm cover is rotated and locked, the two-arm cover is not easily removed, so that the ventilation sheet sandwiched by the two-arm cover is securely fixed.

  Therefore, since the two-arm cover is rotated and locked to the terminal base, the structure is not complicated, the water immersed in the vent hole is reliably waterproofed by the vent sheet, and the diaphragm of the pressure switch is broken. Even if oil flows into the switch, the ventilation sheet can be prevented from peeling off and rising, so that the oil does not easily flow out of the ventilation hole unless the ventilation sheet is broken.

Like 2nd invention, the latching receiving part provided in the recessed part of the terminal base can be comprised from a channel | path part and a prevention part.
That is, the passage portion is formed as a region for moving the locking projection provided on the arm portion of the two-arm cover, and the blocking portion is formed so as to prevent the locking projection from coming out and returning. By doing so, the two-arm cover cannot be easily removed.

The third invention is characterized in that a substantially circular rib which is discontinuous is provided on the two-arm cover as a pressing portion of the above-described ventilation sheet.
That is, the discontinuous portion of the rib serves as a ventilation passage for the ventilation sheet, and the discontinuous portion serves as a conduction path for draining water on the surface of the ventilation sheet.
Therefore, by configuring in this way, the peripheral portion of the ventilation sheet is pressed evenly by the ribs, and the two-arm cover is downsized, and the structure is simplified to reduce the component cost and the manufacturing cost of the mold. Can be.

It is a front view of a pressure switch shown as one embodiment. It is the sectional view on the AA line on FIG. It is the BB line expanded sectional view on FIG. It is the elements on larger scale of the said pressure switch which showed the state before attaching a ventilation sheet and a 2 arm cover. It is CC sectional view taken on the line in FIG. It is a partial expanded front view which shows the latching receiving part provided in the terminal base of the above-mentioned pressure switch. It is the DD sectional view taken on the line in FIG. It is the elements on larger scale of the latching receiving part similar to FIG. It is the expansion perspective view which looked at the 2 arm cover with which an above-described pressure switch is provided from the back side. It is an enlarged front view of the plane part of the said terminal base which shows the state before attaching a 2 arm cover. FIG. 11 is an enlarged front view similar to FIG. 10 showing a state before the two-arm cover and the ventilation sheet are set and the two-arm cover is rotated and attached. It is an enlarged front view similar to FIG. 10 which shows the state which rotated and attached the 2 arm cover and has arrange | positioned the ventilation sheet. It is the figure which showed the back side of the enlarged front view of FIG. It is an enlarged front view of the latch receiving part similar to FIG. 8 which showed the rotation process of the two-arm cover. It is an enlarged front view of the latching receiving part similar to FIG. 14 which showed the latching state of the 2 arm cover. It is sectional drawing of the pressure switch shown as a prior art example.

Next, embodiments of the present invention will be described with reference to the drawings.
1 is a front view of a pressure switch that operates under a predetermined positive pressure, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 3 is an enlarged cross-sectional view taken along line BB in FIG.

As shown in these drawings, in this pressure switch, the terminal base 52 is fastened to the body 51 as in the conventional example, and the diaphragm 53 is fixed to the inner space formed by the body 51 and the terminal base 52. A contact point (ground plate) 54, a movable contact point (contact cap) 55, a coil spring 56, and a terminal 57 are disposed. The inner space is divided into a pressure chamber 58 and an operation chamber 59 by the diaphragm 53 in two minutes. Has been.
The diaphragm is made of a flexible material such as rubber, and an O-ring 60 is provided near the crimping portion of the body 51 so that the body 51 and the terminal base 52 are intimately coupled.

The pressure switch is always joined to the fixed contact 54 by the spring force of the coil spring 56 provided between the movable contact 55 and the terminal 57.
Further, a push block 61 is provided between the diaphragm 53 and the fixed contact 54, and the interlocking portion 61 a of the push block 61 is brought into contact with the movable contact 55 through the hole 54 a of the fixed contact 54.

  That is, when a predetermined pressure or more is applied to the pressure chamber 58 and the diaphragm 53 fluctuates (bends) to the movable contact 55 side, the push block 61 responsive to the diaphragm 53 causes the movable contact 55 to be fixed to the fixed contact 54 by the interlocking portion 61a. Operates away from

On the other hand, in this pressure switch, a recessed portion 62 having a bottom surface as a flat portion 62a is formed around the terminal base 52, and a vent hole 63 is provided in which the flat portion 62a of the recessed portion 62 communicates with the operation chamber 59. It is.
As described above, the vent 63 communicates the operating chamber 59 with the atmospheric pressure, and keeps the operating chamber 59 at the atmospheric pressure.

Further, a vent sheet 64 is attached to the flat portion 62 a of the recess 62 so as to cover the hole opening of the vent hole 63.
Specifically, a dish-like groove 62b for arranging the ventilation sheet 64 is formed in the flat portion 62a, and the ventilation sheet 64 is stuck in the dish-like groove 62b.
The ventilation sheet 64 is the same as that of the conventional example, and is a ventilation sheet that allows only a gas to pass therethrough and prevents the passage of a solution (for example, water), and prevents water from entering the ventilation holes 63.
The ventilation sheet 64 is fixed to the inner bottom surface of the dish-shaped groove 62b using a double-sided adhesive tape or an adhesive.

On the other hand, the two-arm cover 65 is locked to the flat portion 62a of the above-described recess 62, and the two-arm cover 65 prevents the ventilation sheet 64 from being peeled off or lifted.
4 is an enlarged front view showing the recessed portion 62 of the terminal base 52, and FIG. 5 is a cross-sectional view taken along the line CC in FIG.
As shown in the figure, the flat portion 62a of the recessed portion 62 includes the hole 63a of the vent hole 63, the dish-shaped groove 62b as described above, and the latch receiving portions 66 and 67 provided on both sides of the dish-shaped groove 62b. Is provided.

As described above, the dish-shaped groove 62b adheres the ventilation sheet 64 formed in a disk shape to the bottom surface thereof.
Further, as shown in detail in FIGS. 6 to 8, the latch receiving portion 66 includes a passage groove 66a for moving the latching projection 65a (see FIG. 6) of the two-arm cover 65, and the latching projection 65a. It comprises a blocking plate portion 66b that prevents the locking protrusion 66a from slipping out and a blocking locking portion 66c that blocks the return movement of the locking projection 65a.

Although FIGS. 6 to 8 show the locking receiving portion 66, the other locking receiving portion 67 has the same configuration, and includes a passage groove 67a, a blocking plate portion 67b, and a blocking locking portion 67c. It is.
These passage grooves 66a and 67a are groove portions provided along the outer circle of the hole 63a, and serve as passage portions of locking protrusions 65a and 65b provided on the two-arm cover 65 described later.
Further, the blocking plate portions 66b and 67b and the blocking locking portions 66c and 67c are locking portions communicating with the groove portions, and locking protrusions 65a and 65b provided on the two-arm cover 65 described later are pulled out and returned. It becomes the prevention part.
That is, the locking projections 65a and 65b provided on the two-arm cover 65 pass through the passage grooves 66a and 37a (groove portions) that are passage portions, and then the blocking plate portions 66b and 67b that prevent the withdrawal and return movement. Further, withdrawal and return movement are blocked by the blocking locking portions 66c and 67c (locking portions).
Reference numeral 68 shown in each figure indicates a tapered surface for flowing water out of the switch.

The two-arm cover 65 is formed of a synthetic resin material, and as can be seen from FIGS. 3 and 9, locking arms 65c and 65d are formed to protrude at both ends of the cover portion 65b, and these locking arms 65c and 65d are formed. Locking protrusions 65a and 65b are provided at the tip of the stub.
Further, on the back surface of the cover portion of the two-arm cover 65, a non-continuous portion 69 is provided and a rib 65e formed in a substantially circular shape is provided. The rib 65e serves as a pressing portion that presses against the ventilation sheet 64. Moreover, the discontinuous part 69 forms a conduction path through which air or water passes.
Specifically, the discontinuous portion 69 forms a conduction path through which air or water passes together with a communication groove 62c (see FIGS. 4 and 5, etc.) communicated with a dish-shaped groove 62b in which the ventilation sheet 64 is disposed. To do.

Next, attachment of the two-arm cover 65 will be described with reference to FIGS.
First, as shown in FIG. 10, before attaching the two-arm cover 65, the ventilation sheet 64 is attached to the inner bottom surface of the dish-like groove 62 b of the recess 62.
Then, the locking arms 65c and 65d of the two-arm cover 65 are inserted into the passage grooves 66a and 67a of the locking receiving portions 66 and 67 provided in the recessed portion 62 as shown in FIG.

Thereafter, when the two-arm cover 65 is rotated clockwise in FIG. 11, the locking projections 65 a and 65 b of the locking arms 65 c and 65 d prevent the locking receiving portions 66 and 67 as shown in FIG. 12. At the same time as it goes around the lower side of the plate portions 66b and 67b, the return movement is blocked by the blocking locking portions 66c and 67c.
Accordingly, the locking projections 65a and 65b are prevented from coming out by the blocking plates 66b and 67b, and the return movement of the locking projections 65a and 65b is blocked by the blocking locking portions 66c and 67c.

In the process in which the locking projection 65a of the two-arm cover 65 moves as described above, the locking arm 65 abuts against the wall surface 66a1 of the passage groove 66a provided in the locking receiving portion 66 as shown in FIG. The 65c is slightly bent inward to store elastic force.
From this, when the locking projection 65 advances to the area of the blocking locking portion 66c, as shown in FIG. 15, the locking projection 65a rushes into the blocking locking portion 66c at once due to its elastic force and returns. Movement is prevented.
14 and 15 show the locking operation of the locking projection 65a of the two-arm cover 65 with respect to the locking receiving portion 66, the locking projection of the other locking receiving portion 67 and the two-arm cover 65 is shown. The same operation is performed for the portion 65b.

In this way, the two-arm cover 65 is securely attached.
Therefore, the ventilation sheet 64 is sandwiched between the bottom surface of the dish-shaped groove 62b and the two-arm cover 65, and the vicinity of the periphery of the ventilation sheet 64 is pressed by the rib 65e of the two-arm cover 65. (See Figures 2 and 3)
As a result, there is no problem such as separation or floating of the ventilation sheet 64, and the ventilation sheet 64 is disposed as a ventilation sheet that reliably covers the hole 63a of the ventilation hole 63.

Further, if slopes 66b1 and 67b1 (see FIG. 7) are provided on the blocking plate portions 66b and 67b of the locking receiving portions 66 and 67, when the two-arm cover 65 is attached, the locking projections 65a and 65b Since the two-arm cover 65 is entirely pulled toward the ventilation sheet, the ventilation sheet 64 is uniformly pressed by the rib 65e with a predetermined force.
Therefore, the ventilation sheet 64 is not cracked.
Although FIG. 7 shows only the locking receiving portion 66, the inclined plate 67b1 is similarly provided for the blocking plate portion 67b of the other locking receiving portion 67.

The above-mentioned pressure switch can be used as a pressure switch for detecting the oil pressure of the engine in the engine equipment of the vehicle.
That is, when the oil pressure of the engine applied to the pressure chamber 58 is a pressure that does not change the diaphragm 53, the operation state shown in FIG. 2 is established, and the movable contact 55 is in contact with the fixed contact 54.
Therefore, the signal path of the terminal 57, the coil spring 56, the movable contact 55, the fixed contact 54, and the body 51 is formed, and the switch ON signal is output.

  When the oil pressure of the engine applied to the pressure chamber 58 is a pressure that fluctuates the diaphragm 53, the diaphragm 53 fluctuates to the movable contact side, so that the push block 61 moves upward in FIG. Since the movable contact 55 is pushed by the interlocking portion 61a and is separated from the fixed contact 54, the signal path is opened and a switch OFF signal is output.

On the other hand, in the operation chamber 59 of the pressure switch, air outside the switch flows through the vent hole 63 and the vent sheet 64 and is maintained at the atmospheric pressure. Therefore, regardless of the fluctuation of the diaphragm 53, the movable contact 55 Will be smooth.
In addition, since the two-arm cover 65 is provided for washing water when the vehicle is washed, the washing water is not directly projected onto the ventilation sheet 64.

Even if water is immersed in the place where the ventilation sheet 64 is disposed, water is cut off by the ventilation sheet 64, so that water does not flow into the ventilation hole 63, and the fixed contact 54, the movable contact 55, etc. It will not be corroded by submerged water.
Further, even if the diaphragm 53 of the pressure switch is broken and the engine oil flows into the operation chamber, it is blocked by the ventilation sheet 64 and the two-arm cover 65 can prevent the ventilation sheet 64 from being peeled off and lifted. Unless the oil is broken, the risk of oil flowing out of the switch from the vent hole 63 can be reduced.

  Furthermore, since the ventilation sheet 64 is not only adhered to the bottom surface of the dish-shaped groove 62b, but is pressed by the two-arm cover 65 attached to the terminal base 52, the ventilation sheet 64 peels off or floats up. There is no such a thing, and arrangement | positioning of the ventilation sheet 64 will become reliable.

Further, the above-described pressure switch can be easily attached with one touch by rotating the two-arm cover 65 clockwise.
On the other hand, although it is conceivable to screw the two-arm cover, the structure of the terminal base becomes complicated, and the screwed portion may be loosened due to the vibration of the vehicle and the two-arm cover may be detached.

  Further, the two-arm cover 65 is formed of a synthetic resin material, and the locking arms 66 and 67 are bent and elastically deformed, and the return elasticity is used to lock the locking arm to the locking portion and to be attached. Therefore, the attachment becomes simple, and even if it is necessary to remove it, it can be removed by rotating the locking arms 66 and 67 while being bent.

The present invention can be similarly implemented as a negative pressure switch.
When performing in this way, when the pressure below the predetermined pressure is not applied to the pressure chamber, the diaphragm does not change so that the movable contact comes into contact with the fixed contact and the switch is turned ON. When the pressure is applied, the diaphragm fluctuates, and the movable contact linked to the fluctuation is separated from the fixed contact, and the switch is turned off.

  The present invention can be applied as a pressure switch for detecting a vehicle braking pressure tank, a vehicle engine oil pressure, or the like.

51 Body 52 Terminal base 53 Diaphragm 54 Fixed contact 55 Movable contact 58 Pressure chamber 59 Operating chamber 61 Push block 62 Recessed portion 62a Flat portion 62b Dish groove 62c Communication groove 63 Vent hole 64 Vent sheet 65 Bi-arm cover 65a, 65b Locking Protruding portions 65c, 65d Locking arm 65e Ribs 66, 67 Locking receiving portions 66a, 67a Passage grooves 66b, 67b Blocking plate portions 66c, 67c Blocking locking portions

Claims (3)

A diaphragm is arranged in an internal space formed between the body and the terminal base, and the internal space is divided into an operation chamber and a pressure chamber by the diaphragm, and interlocked with a diaphragm that responds to a pressure change in the pressure chamber. In a pressure switch having a contact portion that opens and closes,
The terminal base is provided with a receiving hole provided at a target position centered on a vent hole formed in the periphery of the terminal base and communicating with the operation chamber, and a vent hole of the vent hole located in the recess position. And set up
And each of the above-described locking receiving portions at the target position is formed from a groove portion provided along the outer circle of the hole opening and a locking portion communicating with the groove portion,
Further, a two-arm cover having an arm portion formed to project from the target position of the cover portion in accordance with each of the latch receiving portions, and provided with a latch projection on each arm portion;
A vent sheet that is disposed in the recessed portion of the terminal base and prevents water from entering the hole opening;
The air-permeable sheet is sandwiched between the recessed portion of the terminal base and the two-arm cover, and after the arm portion of the two-arm cover is inserted into the groove portion of the locking receiving portion, the two-arm cover is rotated. Accordingly, the two-arm cover is fixed to the terminal base by locking the locking protrusion with the locking portion of the locking receiving portion. The pressure switch according to claim 1,
The groove portion of the locking receiving portion is a passage portion of the locking projection provided in the two-arm cover, and the locking portion of the locking receiving portion is moved out and returned by the locking projection provided in the two-arm cover. A pressure switch characterized by being formed as a blocking portion. The pressure switch according to claim 1 or 2,
The two-arm cover is provided with a pressing portion made of a substantially circular rib provided with a discontinuous portion, and the two-arm cover is fixed to the terminal base, thereby pressing the ventilation sheet with the pressing portion and A pressure switch characterized in that the discontinuous part of the part is an air circulation part.

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