JPH0439635Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field This invention relates to a pressure switch such as that installed in gas pressure instruments, and more specifically relates to a pressure switch that detects fluid pressure such as gas pressure. .

(b) Prior art In general, pressure switches designed to operate at a low pressure of about 60 mm of water column (60 mmH ₂ O) have a switching operation that corresponds to a slight amount of deformation of the diaphragm. be done.

For example, as shown in FIG. 4, a plunger 41 that moves under the deformation action of a diaphragm
is brought into pressure contact with the intermediate portion of the movable contact piece 42 supported in a cantilever manner, thereby making the movable contact 43 formed at the free end of the movable contact piece 42 correspond to the fixed contact 44 so as to be able to come into contact with and separate from the fixed contact 44, Opening and closing operations are performed between both contacts 43 and 44.

However, in this case, the movable contact piece 42 normally has a plate spring property and flexes greatly, especially toward the free end, so when the middle part of the movable contact piece 42 is pressed by the plunger 41, The contact pressure between the corresponding contacts 43 and 44 at the free end becomes small, making it impossible to obtain stable switch characteristics and resulting in low reliability as a low pressure switch.Therefore, it is desired to increase the contact pressure. Ta.

In addition, as shown in FIGS. 5 and 6, springs 53 and 63 corresponding to the plungers 51 and 61 are attached to the movable contact pieces 52 and 62 whose intermediate portions are pressed by the plungers 51 and 61, so that the contact pressure is increased. Although contact mechanisms configured to increase the
In this case as well, the movable contact piece 5
Since the contact points are provided at the free ends of the plungers 51 and 62, there is a problem in that the contact pressure is lower than the pressure position of the plungers 51 and 61, and the springs 53 and 63 are required.

Furthermore, as shown in FIG.
A contact mechanism is also provided in which both ends of the movable contact piece 72 are formed into contact corresponding parts 73, 73, but in this case, when the middle part of the movable contact piece 72 is pressed with the plunger 74, , movable contact piece 7
Since the contacts correspond to each other at both ends of 2, the contact pressure is distributed to the left and right, reducing the contact pressure.
Two contact corresponding parts 73 are required, and the spring 7
1, resulting in an increase in the number of parts.

(c) Purpose of the invention In view of the above points, this invention has a simple contact structure that does not require a spring, yet can obtain high contact pressure.Moreover, by making the movable contact have a gate-shaped cross section, this movable It is an object of the present invention to provide a pressure switch which can ensure the rigidity of the contact point, is less susceptible to external vibrations etc. by providing the rigidity, and can obtain a highly reliable contact action.

(d) Structure of the invention This invention includes a diaphragm that deforms in response to changes in fluid pressure, a plunger that contacts and moves following the deformation surface of the diaphragm, and a movable contact piece that is pressed by the plunger, The movable contact piece has a free end corresponding to the plunger set as a press corresponding part, and integrally forms a leaf spring piece extending from both ends of the press corresponding part to the proximal end, and extends from the center of the press corresponding part to the proximal end. An independent piece with a gate-shaped cross section extending to the side is integrally formed, a notch is formed along the longitudinal direction of both pieces between the leaf spring piece and the independent piece, and the independent piece is connected to and separated from the fixed contact. The pressure switch is characterized in that the pressure switch is set as a movable contact, and the base end of the movable contact piece is set as an elastic fulcrum.

(E) Function of the device In this device, the diaphragm deforms in response to changes in fluid pressure, and as the plunger moves to follow this deformation, the movable contact piece is elastically displaced, thereby causing a gap between the contact portions. They are brought into contact and separated and are operated by switching, and based on this, changes in fluid pressure are detected.

(f) Effects of the invention According to this invention, when the free end of the movable contact piece is pressed by the plunger, the movable contact piece bends in an arch with the base end as an elastic fulcrum and is elastically displaced.
When the movable contact of the elastically displaced intermediate part of the independent piece comes into contact with and separates from the fixed contact, the contact position of the intermediate part of the independent piece uses the proximal end as an elastic fulcrum compared to the free end, so the amount of deflection is reduced. As a result, the elastic resistance acts stronger at the intermediate position of the independent piece than at the free end side, resulting in a higher contact pressure. In addition, since the contact point is provided at one point, contact pressure is concentrated and contact is made, resulting in highly accurate and stable switching characteristics.

In addition, since no spring is required, the number of parts and assembly steps are reduced, and costs can be definitely reduced, and the reliability of the switch can be precisely increased.

In addition, in order to prevent the movable contact piece from bending significantly in conjunction with the elastic displacement of the movable contact piece, there is a
An independent piece is provided through the notch, and the cross-sectional shape of this independent piece is gate-shaped to give it rigidity, so the amount of deflection of the above-mentioned movable contact (independent piece) is suppressed, and the opening and closing between the contact parts is controlled. Appropriate movement can be obtained, and by adding rigidity, it is less susceptible to external vibrations, etc., making it an even more reliable pressure switch.

(G) Embodiment An embodiment of this invention will be described below in detail based on the drawings.

The drawings show a pressure switch, FIGS. 1 and 2.
In the figure, this pressure switch 11 is comprised of a pressure receiving case 12 and a switch base 13 fitted into this pressure receiving case 12.

The above-mentioned pressure receiving case 12 is formed into a cylindrical body,
The upper end of this cylindrical body has a flange 14 for attaching a switch, and a protective disc 16 equipped with several pressure receiving holes 15 is attached from above to the opening of the cylindrical body on the side of this flange 14. The switch base 13 is fitted into the pressure receiving case 12 with the pressure receiving hole 15 communicating with the pressure receiving chamber 17. metal diaphragm 18
is set freely for reversal operation.

The diaphragm 18 has a central portion formed into an inverted portion 18a.
A stepped portion 18b is formed on the side of the outer peripheral edge, and this stepped portion 18b is sandwiched between the upper inner peripheral groove 19 of the pressure receiving case 12 and the peripheral edge of the protective disc 16, and laser welding 20 is performed from the outside thereof. Thus, the pressure receiving case 12 and the diaphragm 18 are integrated, and the sandwiched portion is sealed.

Further, a peripheral wall portion 2 is provided on the lower surface side of the pressure receiving case 12.
1 is formed, and a connecting flange 24 provided on the switch base 13 is fitted into an inner circumferential groove 23 at the lower end of this recess 22, thereby connecting the pressure receiving case 12 and the switch base 13. The upper surface of the fitted switch base 13 is inserted into the recess 22 of the pressure receiving case 12, and is disposed in the pressure receiving chamber 17 facing the diaphragm 18 described above.

The above-mentioned switch base 13 is connected to the pressure receiving case 12.
The switch base 13 is provided with a cylindrical shape that can be inserted into the recess 22 of the switch base 13, and the above-mentioned connecting flange 24, and a pair of opposing first lead terminals 25.
The second lead terminal 26 is insert-molded, the connecting flange 24 is provided protruding from the outer peripheral surface, each lead terminal 25, 26 is provided vertically from the lower surface, and a plunger guide plate 27 is mounted in the recessed portion of the upper surface. .

A vertical sliding hole 28 is provided through the center of the plunger guide plate 27, into which a plunger 29 is inserted. Further, the interior of the switch base 13 on the lower surface side of the plunger guide plate 27 has a cavity 30, and the lower end of the plunger 29 protrudes into this cavity 30, and the first lead terminal is inserted into the cavity 30. A movable contact piece 31 extending through the plunger 25 is switched in correspondence with the plunger 29.

The head of the plunger 29 is located within the pressure receiving chamber 17, and this head expands into a disk portion with a much larger diameter than the shaft portion inserted into the plunger guide plate 27, Further, the wide peripheral edge portion of the upper surface is provided to protrude upward to form an annular peripheral edge protrusion 32, and this peripheral edge protrusion 32 is brought into contact with the inverted portion 18a of the diaphragm 18.

Thereby, when the diaphragm 18 is reversed, the peripheral protrusion 32 comes into uniform contact with the diaphragm 18 over a wide range, and serves to efficiently improve the stability of contact with the diaphragm 18.

By the way, the inner ends of both lead terminals 25 and 26 inserted into the switch base 13 are led out from the left and right sides of the empty chamber 30, and as shown in FIGS. 2 and 3, the inner ends of the first lead terminal 25 A movable contact piece 31 having a movable contact 34 is connected to the movable contact piece 31 , and a fixed contact 33 is formed at the inner end of the second lead terminal 26 . are provided facing each other in the direction.

The above-mentioned movable contact piece 31 is formed of an extremely thin conductive plate spring material, and its base end is connected to the first lead terminal 25.
is connected to the inner end of the plunger as an elastic fulcrum, and a free end extending from this is biased upward and extends, and this extending end is set at the pressing corresponding part 35 corresponding to the lower end of the plunger 29. .

Further, leaf spring pieces 8, 8 extending from both ends of the above-mentioned pressure corresponding part 35 toward the base end are integrally formed, and an independent piece 10 having a gate-shaped cross section extending from the center of the above-mentioned pressure corresponding part 35 toward the base end is also integrally formed. Form this independent piece 10
is set on the movable contact 34 that comes into contact with and separates from the fixed contact 33, and a notch 9 is provided between the above-mentioned leaf spring pieces 8, 8 and the above-mentioned independent piece 10 along the longitudinal direction of these pieces 8, 10. , 9.

That is, as shown in FIG. 3, the above-mentioned movable contact 34 is located at the center of the movable contact piece 31 so that it does not bend significantly in conjunction with the elastic displacement of the movable contact piece 31 that receives the pressing force of the plunger 29. A notch is formed in the part toward the proximal end using the pressure corresponding part 35 side as a tilting fulcrum, and this notched independent piece 10 is bent into a portal shape in cross section to provide rigidity. 3 (upper left side in FIG. 3) is locked to the upper end locking step 36 of the first lead terminal 25 to restrict upward movement.
As a result, the movable contact 3 as this independent piece 10
By suppressing the amount of deflection of 4, it is possible to obtain movement suitable for contact and separation between the contact parts, and by adding rigidity, it is less susceptible to external vibrations, etc., resulting in even more reliable contact. Effect can be obtained.

Then, when the plunger 29 is in the downward movement position,
The movable contact piece 31 is pushed down to separate the contacts 33 and 34, thereby cutting off the conduction between the lead terminals 25 and 26. On the other hand, when the plunger 29 is in the upward movement position,
The movable contact piece 31 moves upward to bring the contacts 33 and 34 into contact and short-circuit the lead terminals 25 and 26.

At this time, the contact position where the movable contact piece 31 approaches and separates at the middle part uses the base end as an elastic fulcrum compared to the free end, so the amount of deflection when receiving pressure is smaller, and as a result, the free end is more flexible than the free end. Also, the elastic drag at this intermediate position acts strongly, resulting in high contact pressure and stable switching characteristics.

In this way, a switch section 37 corresponding to the vertical movement of the plunger 29 is constructed in the switch base 13, and the on/off operation of this switch section 37 is controlled by a diaphragm that operates in reverse in response to changes in the pressure of gas or other fluids. Made by 18. At this time, the distance between the vertically opposing microcontacts 33 and 34 is adjusted by the adjustment screw 38 to a distance suitable for opening and closing.

In addition, a cut groove 39 for air inflow is formed at one location on the outer peripheral edge of the above-mentioned connecting flange 24. By providing this cut groove 39, the air can enter the outer circumference of the switch base 13 and the groove. An atmospheric pressure passage 40 is formed which communicates with the outer circumferential portion of the pressure receiving case 12 on the side opposite to the pressure receiving surface of the diaphragm through a gap with the portion 22, thereby allowing the diaphragm 18 to deform.

In the pressure switch configured in this way, the inverted portion 18a of the diaphragm 18 deforms into an arc shape in response to fluid pressure, and the plunger 29 pressed against this deformed surface pushes down the pressure corresponding portion 35 of the movable contact piece 31. The contacts 33 and 34 are spaced apart to detect a constant fluid pressure load.

When the fluid pressure drops, the inverted portion 18a of the diaphragm 18 inverts back to its original state,
Based on this, the plunger 29 was pushed upward by the biasing pressure of the movable contact piece 31, and the movable contact 34 formed on the movable contact piece 31 came into contact with the upper fixed contact 33 and became conductive, causing the fluid pressure to drop. Output a signal.

In this case, when the pressure corresponding part 35 set at the free end of the movable contact piece 31 is pressed by the plunger 29, the movable contact piece 31 bends in an arch with the base end as an elastic fulcrum and is elastically displaced. When the elastically displaced movable contact 34 of the intermediate portion contacts the fixed contact 33 and conducts, the contact position of the intermediate portion uses the base end as an elastic fulcrum compared to the free end, so the amount of deflection is small. The elastic drag at this intermediate position acts strongly, resulting in high contact pressure.

In addition, since the contact point is provided at one point, contact pressure is concentrated and contact is made, resulting in highly accurate and stable switching characteristics.

Moreover, in order to prevent large deflection in conjunction with the elastic displacement of the movable contact piece 31, an independent piece 10 is provided at the center of the leaf spring pieces 8, 8 through notches 9, 9. In addition to setting the movable contact 34, the cross-sectional shape of the independent piece 10 is gate-shaped to provide rigidity, so the amount of deflection of the movable contact 34 (independent piece 10) described above is suppressed, and the distance between the contact parts is This has the effect of providing movement suitable for opening and closing, and in addition, by adding rigidity, it becomes less susceptible to the effects of external vibrations, etc., and has the effect of significantly improving reliability.

Regarding the correspondence between the configuration of this device and the above-described embodiment, the modified aspect of this device corresponds to the inverted portion 18a of the embodiment, but this device is not limited to the configuration of the above-described embodiment. do not have.

Further, in the above embodiment, the movable contact piece 31 is constructed separately from the first lead terminal 25, but it is also possible to form both 31 and 25 integrally.

[Brief explanation of the drawing]

The drawings show an embodiment of this invention, with Fig. 1 being a longitudinal sectional view of the pressure switch, Fig. 2 being an exploded perspective view of the pressure switch, Fig. 3 being a perspective view of the lead terminal and movable contact piece, and Fig. 4 being a perspective view of the lead terminal and movable contact piece. 7 is an explanatory diagram of the operation of a conventional pressure switch. 8...Plate spring piece, 9...Notch, 10...Independent piece, 18...Diaphragm, 18a...Reverse portion,
29... Plunger, 31... Movable contact piece, 33
...Fixed contact, 34...Movable contact, 35...Press response part.

Claims (1)

[Claims for Utility Model Registration] A diaphragm 18 that deforms in response to changes in fluid pressure, a plunger 29 that contacts and moves following the deformation surface 18a of the diaphragm 18, and a movable contact piece 31 that is pressed by the plunger 29. The movable contact piece 31 has a free end corresponding to the plunger 29 set in a press corresponding part 35, and plate spring pieces 8, 8 extending from both ends of the press corresponding part 35 toward the base end are integrally formed. An independent piece 10 having a gate-shaped cross section is integrally formed and extends from the center of the pressure corresponding portion 35 toward the proximal end, and between the leaf spring pieces 8, 8 and the independent piece 10, both pieces 8, 10 are provided. A pressure switch in which notches 9, 9 are formed along the longitudinal direction, the independent piece 10 is set as a movable contact 34 that comes into contact with and separates from the fixed contact 33, and the base end of the movable contact piece 31 is set as an elastic fulcrum. .