JPH0355226Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an improvement in a pressure switch whose settings open and close in response to changes in gas or liquid pressure.

[Conventional technology]

In general, pressure switches are widely used as vacuum alarm switches for automobiles, etc., but the pressure switches used in the past have a chamber surrounded by a case and a terminal base, such as the one shown in Japanese Utility Model Publication No. 59-43630. The inside is divided into two by a diaphragm, one being a pressure receiving chamber and the other being a back pressure chamber, a movable contact connected to the diaphragm, a fixed contact that contacts the movable contact according to the displacement of the diaphragm, and a potential of the fixed contact. It consists of a terminal lead that leads the air to the outside, and a ventilation hole that communicates the back pressure chamber with the outside so that the operating pressure is not affected by temperature changes.

[Problem that the invention attempts to solve]

However, since the above-mentioned conventional pressure switch is provided with a ventilation hole that communicates the back pressure chamber with the outside, its waterproofness is inevitably insufficient, and if moisture, etc. infiltrates through the ventilation hole, the moisture will leak out. etc. directly adhere to the contact portion, which is composed of a movable contact and a fixed contact, and corrode the contact portion, causing a decrease in the reliability of the switch. For this reason, recent efforts have been made to cover the outer periphery of the terminal base and terminal lead of pressure switches with waterproof boots to prevent moisture from entering through the ventilation holes as much as possible, but this is not only difficult to assemble, but also It had many drawbacks, such as high cost and the waterproofing properties of waterproof boots.

The present invention was proposed in view of the above-mentioned drawbacks of the conventional technology, and it is easy to assemble, and even if moisture etc. infiltrates through the ventilation hole, the moisture etc. will adhere to the contact area. It is an object of the present invention to provide an inexpensive and highly reliable pressure switch that can prevent corrosion of the pressure switch.

[Means for solving problems]

In order to solve the above problems, the present invention divides the inside of the chamber surrounded by the case and the terminal base into two parts by a diaphragm, making one a pressure receiving chamber and the other a back pressure chamber, and connecting a movable contact connected to the diaphragm. , a pressure switch comprising a fixed contact that contacts the movable contact according to the displacement of the diaphragm, a terminal lead that leads the potential of the fixed contact to the outside, and a ventilation hole that communicates the back pressure chamber with the outside, the movable contact and the fixed contact is covered with an inner cover in the back pressure chamber, and a ventilation groove connected to the ventilation hole is arranged between the inner wall of the back pressure chamber and the inner cover to constitute a pressure switch. It is characterized by:

[Effect]

Since the pressure switch of the present invention is constructed as described above, if there is a displacement of the diaphragm or a change in temperature, some of the air in the back pressure chamber may flow out to the outside through the ventilation hole, or conversely, it may flow out from the outside. However, even if moisture is included when it flows in, the moisture will pass through the ventilation groove connected to the ventilation hole, so the movable contact covered by the inner cover and the fixed contact will be separated. Moisture does not adhere directly to the contact area.

〔Example〕

Hereinafter, the present invention will be specifically explained based on embodiments shown in the drawings.

FIG. 1 is a partial sectional view of a pressure switch showing an embodiment of the present invention.

In the figure, 1 is the case, 12 is the terminal base,
The inside of the chamber surrounded by the case 1 and the terminal base 12 is divided into two left and right by a diaphragm 6, one being a pressure receiving chamber A and the other being a back pressure chamber B.
It is divided into. The outer circumference of the diaphragm 6 is airtightly sandwiched between the mating surfaces of the case 1 and the terminal base 2, and the center of the diaphragm 6 is
The pressure receiving chamber A side is held by a spring guide 5, and the back pressure chamber B side is held airtight by a mover 8 via a rubber washer 7, and the center of the mover 8 connected to the diaphragm 6 on the back pressure chamber B side At the tip,
A movable contact 10 is formed. 13 is a terminal lead whose rear end is inserted into the back pressure chamber B, and the rear end of the terminal lead 13 is formed with a fixed contact 11 that contacts the movable contact 10 according to the displacement of the diaphragm 6. The potential of the fixed contact 11 is
It is designed to be led to the outside via a terminal lead 13. 3 is a spring support housed in the pressure receiving chamber A side, and a spring 4 is interposed between the spring support 3 and the spring guide 5, and presses the center of the diaphragm 6 by adjusting the adjustment screw 2. By changing the pressing force, the operating pressure of the diaphragm 6 can be adjusted. C is a ventilation hole that communicates the back pressure chamber B with the outside, and is provided between the terminal base 12 and the terminal lead 13. In addition, 14
is a mating connection terminal attached to the protrusion of the terminal lead 13. 9 is terminal lead 13
A bowl-shaped inner cover attached to the rear end.
It covers the movable contact 10 and fixed contact 11 in the back pressure chamber B, and is arranged as shown in the figure to face the ventilation hole C, and the space between the inner wall of the back pressure chamber B and this inner cover 9. A ventilation groove 15 is formed in.

In the pressure switch of the present invention having the above configuration, for example, if the vacuum pressure introduced into the pressure receiving chamber A changes abnormally and the pressure inside the pressure receiving chamber A becomes too low, the diaphragm 6 deforms and the spring 4 The movable contact 10 and the fixed contact 11
The contact consisting of is opened. The inside of the back pressure chamber B is kept airtight and waterproof by the diaphragm 6, and at this time, the deformation of the diaphragm 6 allows outside air to enter the back pressure chamber B through the ventilation hole C and the ventilation groove 15. However, even if it contains moisture, the moisture can be absorbed by the ventilation groove located between the inner wall of the back pressure chamber B and the inner cover 9 and connected to the ventilation hole C. 15, moisture etc. do not directly adhere to the contact portion covered by the inner cover 9, so the contact portion is not corroded by moisture etc. When the vacuum pressure becomes normal, the diaphragm 6 is pressed by the spring 4 and returns to its original position, and the movable contact 10 contacts the fixed contact 11, closing the contact again, and the air in the back pressure chamber B side is released. A part of the air is discharged to the outside through the ventilation hole C. In addition, since the back pressure chamber B is always communicated with the outside through the ventilation groove 15 and the ventilation hole C, even if the air in the back pressure chamber B expands or contracts due to temperature changes, the back pressure chamber B Since the internal pressure is balanced with the external pressure through the ventilation holes C and the ventilation grooves 15, the switch operates by accurately following fluctuations in vacuum pressure.

Next, FIG. 2 is a sectional view of a pressure switch showing another embodiment of the present invention, but the basic structure is the same as that of the first embodiment.
Since it is the same as the pressure switch of the embodiment shown in the figure, the same reference numerals are given to the members corresponding to the members shown in FIG. 1, and redundant explanation will be omitted.

The embodiment shown in FIG. 2 differs from the embodiment shown in FIG. 1 in the terminal shape, and shows the case where it is applied to a flat terminal type. Therefore, in the embodiment shown in FIG. 2, the shape and configuration of the terminal base 12 and terminal lead 13, the position of the ventilation hole C, etc. are slightly different from the embodiment shown in FIG. 1, but the operation of the switch and the The roles of the accompanying ventilation groove 15 and inner cover 9 are the same as in the embodiment shown in FIG.

However, it goes without saying that the present invention is not limited to the terminal structure shown in FIGS. 1 and 2, but can be widely applied to pressure switches having various terminal structures.

[Effect of idea]

As specifically explained above, according to the pressure switch of the present invention, when there is a displacement of the diaphragm or a change in temperature, some of the air in the back pressure chamber flows out to the outside through the ventilation hole, or vice versa. However, even if moisture is included at the time of inflow,
The moisture passes through the ventilation groove connected to the ventilation hole, so moisture does not directly adhere to the contact area, which is made up of a movable contact and a fixed contact covered by the inner cover. There is no fear of corrosion caused by such things, and the reliability of the switch can be improved.

Furthermore, since the ventilation groove can be incorporated into the back pressure chamber together with the terminal lead, assembly is easy and manufacturing can be done at low cost. It has great advantages such as
This makes it possible to provide a pressure switch that is extremely effective in practice.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention, and FIG. 2 is a sectional view of another embodiment. 1... Case, 2... Adjustment screw, 3... Spring support, 4... Spring, 5... Spring guide, 6... Diaphragm, 7... Rubber washer, 8... Mover, 9... Inner cover,
10...Movable contact, 11...Fixed contact, 12...
Terminal base, 13...Terminal lead,
14...Mate connection terminal, 15...Ventilation groove, A...
...Pressure receiving chamber, B...Back pressure chamber, C...Vent hole.

Claims (1)

[Scope of utility model registration request] The inside of the chamber surrounded by the case and the terminal base is divided into two by a diaphragm, one being a pressure receiving chamber and the other being a back pressure chamber, and a movable contact connected to the diaphragm is connected to the movable contact according to the displacement of the diaphragm. In a pressure switch, the movable contact and the fixed contact are connected to each other in the back pressure chamber, and includes a terminal lead that leads the electric potential of the fixed contact to the outside, and a ventilation hole that communicates the back pressure chamber with the outside. A pressure switch covered with a cover, wherein a ventilation groove connected to the ventilation hole is arranged between the inner wall of the back pressure chamber and the inner cover.