JPH07211206A - Pressure switch - Google Patents

Abstract

PURPOSE:To provide a pressure switch with high reliability which does not produce dust at the time of the welding of housings and in which contact failure does not occur. CONSTITUTION:A first housing 1 in which electric switches 3, 4 are built and a second housing 2 in which a switch driving means 5 is built are made of plastics and they are fitted with each other and a circular conductive material 9 is put along the whole circumference of the contact parts of both housings 1, 2. High frequency current is applied to the conductive circuit put in the outer part of both housings 1, 2 to generate heat in the conductive material 9 attributed to induced current generated in the conductive material 9 and thus the first housing 1 and the second housing 2 are melted and welded each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure switch that receives a pressure of a fluid and operates an electric switch according to the increase or decrease of the pressure.

Such a pressure switch is mounted, for example, on the high pressure side of a refrigeration cycle of a vehicle air conditioner,
It is used to turn off the electrical contacts connected to the compressor when the high-pressure side pressure of the refrigeration cycle circuit rises or falls abnormally.

[0003]

2. Description of the Related Art A pressure switch must be provided with an electric switch that can be opened and closed, and a switch driving means that is displaced by receiving the pressure of fluid to open and close the electric switch.
Incorporating them into one housing makes the assembly process extremely troublesome.

Therefore, generally, a first housing for accommodating the electric switch and a second housing for accommodating the switch driving means are separately formed of plastic, and the electric switch and the switch driving means are formed. After assembling each of the housings into each housing, both housings are integrally connected by ultrasonic welding.

[0005]

However, when the first and second plastic housings are ultrasonically welded, plastic dust is scattered from the vicinity of the welded portions of both housings into the housings in the welding process, and the electric There has been a problem that the switch causes a contact failure and may not be turned on. Moreover, this dust is extremely fine, and if it adheres to the contact due to static electricity or the like, it cannot be removed even by suction.

Therefore, an object of the present invention is to provide a highly reliable pressure switch that does not generate dust when welding housings and does not cause contact failure.

[0007]

To achieve the above object, in the pressure switch of the present invention, an electric switch that can be opened and closed is arranged in the first housing and is displaced by receiving the pressure of fluid. Switch driving means for driving the electric switch to open and close is disposed in the second housing, and
In a pressure switch in which the housing and the second housing are mechanically connected, the first housing and the second housing are both made of plastic and fitted together, and the entire circumference of the contact portion of both housings is A ring-shaped conductive member is arranged along the path, and a high-frequency current is caused to flow in a conductive path arranged outside the both housings, whereby the conductive member is heated by an induced current generated in the conductive member, and the first conductive member is heated. It is characterized in that the housing and the second housing are welded.

[0008]

When a high-frequency current is passed through a conductive path arranged outside the housing, an induced current flows through an annular conductive member arranged at a fitting portion between the first housing and the second housing, and the conductive member generates heat. Then, the heat causes the contact portions of both housings to be melted and welded to each other. Therefore,
No dust is generated at the time of welding, and the contactability of the electric switch inside the housing is not impaired.

[0009]

Embodiments will be described with reference to the drawings. FIG. 1 shows a pressure switch. This pressure switch includes a first housing 1 in which electrical components such as first and second electric switches 3 and 4 are incorporated, and an electric switch 3 that receives fluid pressure.
It is covered by a second housing 2 in which a reversing plate mechanism 5 (switch driving means) for driving the motor 4 is incorporated.
Both housings 1 and 2 are molded with a thermoplastic material.

Reference numeral 6 denotes a pressure receiving chamber case having a fluid pressure introducing port 6a formed therein, which is fixed to the second housing 2 by caulking the end portion. Reference numeral 7 denotes an outer edge portion of the diaphragm 51 which is brought into close contact with the upper end surface of the second housing 2 and the pressure receiving chamber case 6.
It is an O-ring for sealing the gap between.

Both housings 1 and 2 are formed in a cylindrical shape and are fitted to each other, and in annular grooves 19 and 29 formed in both housings 1 and 2 so as to face and abut on the contact portions of both housings 1 and 2. A ring-shaped conductive member 9 made of, for example, a metal ring is fitted in.

Inside the first housing 1, first and second electric switches 3 and 4 are mounted. Both the electric switches 3 and 4 have movable contacts 3c and 4c attached to the fixed contacts 3a and 4a and the leaf springs 3b and 4b.
In the natural state, the first electric switch 3 is set to be closed, and the second electric switch 4 is set to be opened.

The fixed contacts 3a, 4a and the leaf springs 3b, 4b are respectively connected to the connection terminals 11, 12, 13,
It is fixed to the base end of 14. Each connection terminal 11-14
Are insert-molded integrally with the first housing 1 independently of each other.

On the lower end side of the first housing 1, a connector 10 for connecting to a connector of an external circuit such as another device is integrally formed, in which each connection terminal 1 is formed.
The tips of 1 to 14 project.

The reversing plate mechanism 5 incorporated in the second housing 2 has a diaphragm 51 which is displaced by the pressure in the fluid pressure inlet 6a, and an umbrella-shaped first member which reverses when a pressing force is applied to the peripheral portion. The first, second and third inversion disks 52,
53, 54 are provided, and the respective inverted disks 52, 53,
First and second support wheels 55 and 56 are arranged between 54.

Then, the rod 57 which abuts the lower surface of the first reversing disk 52 pushes the leaf spring 4b of the second electric switch 4 and is stepped by the lower surfaces of the second and third reversing disks 53, 54. The cylindrical sliding cylinder 58 is the first
The electric switch 3 is arranged so as to press the leaf spring 3b.

As shown in FIG. 1, a hole into which the sliding cylinder 58 is slidably fitted is formed in the center of the bottom of the second housing 2, and the periphery thereof forms a bottom surface 2a without any defect. is doing.

Therefore, from there, the third inverted disk 54
The projection 2b that is provided so as to come into contact with the lower surface of the
It is formed into a perfect ring without any breaks in the middle,
The reversing disk 54 of (4) operates accurately without distortion.

The projection 55a projecting from the lower surface of the first support wheel 55 so as to come into contact with the upper surface of the second reversing disk 53 is also formed in a complete annular shape without interruption. The second inverted disk 53 also operates accurately without distortion.

FIG. 2 shows a state immediately before connecting the first and second housings 1 and 2 during assembly. In this state, the first and second electric switches 3 and 4 and all the connection terminals 11 to 14 have already been assembled in the first housing 1, and the reversing plate mechanism 5 has been assembled in the second housing 2. ing.

Further, an annular conductive wire 100 for passing a high frequency current is arranged at a distance from the housings 1 and 2 so as to surround the connecting portion between the first and second housings 1 and 2. ing.

Then, in this state, the upper end portion of the first housing 1 and the lower end portion of the second housing 2 are fitted to each other as shown in FIG.
After the state shown in (1), a high frequency current is passed through the conductive wire 100. Then, as a result, an induced current flows in the conductive member 9 arranged between the housings 1 and 2, and the conductive member 9 generates heat.

Then, the heat causes the surrounding contact portions of the first and second housings 1 and 2 to be melted, and the first housing 1 and the second housing 2 are connected by welding. Therefore, no dust or leakage of the adhesive will occur during welding.

3 to 5 schematically show the operation of the pressure switch of the above embodiment. When the pressure in the fluid pressure inlet 6a is low and the reversing plate mechanism 5 does not operate (the first and second electric switches 3 and 4 are both open), when the pressure becomes higher than a certain level, the diaphragm 51 Is pushed down a little and the second supporting wheel 56 and the like causes the third reversing disk 54 to be reversed as shown in FIG. 3, so that the first electric switch 3 is closed.

When the pressure further rises above a certain level, as shown in FIG. 4, the first reversing disk 52 is reversed and the second reversing disk 52 is reversed.
The electric switch 4 of is also closed. Then, when the pressure further rises above a certain level, as shown in FIG. 5, the second reversing disk 53 is also reversed and the first electric switch 3 is opened.

When the pressure drops, each reversing disk 52,
Each of 53 and 54 re-inverts at a lower pressure value than that at the time of inversion and returns to the original state. In addition, although the above-described embodiment shows an example in which the present invention is applied to a so-called three-action pressure switch, the present invention is not limited thereto and may be applied to, for example, a two-action pressure switch. it can.

[0027]

According to the present invention, since the first housing and the second housing can be welded and connected to each other without generating dust or seeping out of the adhesive at all, electrical connection can be achieved. No contact failure occurs in the switch, and therefore a highly reliable pressure switch can be obtained, and moreover, it is possible to manufacture at low cost with a small number of parts.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a pressure switch according to an embodiment.

FIG. 2 is a vertical cross-sectional view of the pressure switch of the embodiment when assembled.

FIG. 3 is a schematic view showing the operation of the pressure switch of the embodiment.

FIG. 4 is a schematic view showing the operation of the pressure switch of the embodiment.

FIG. 5 is a schematic view showing the operation of the pressure switch of the embodiment.

[Explanation of symbols]

 1 1st housing 2 2nd housing 3,4 Electric switch 5 Inversion board mechanism (switch drive means) 9 Conductive member 100 Conductive wire (conductive path)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kuniharu Baba Inventor, Kuniharu 1211-12, Kabata-cho, Hachioji-shi, Tokyo

Claims (1)

[Claims] 1. An electric switch which can be opened and closed is arranged in a first housing, and a switch drive means for opening and closing the electric switch by being displaced by receiving the pressure of a fluid is provided as a second.
In a housing, wherein the first housing and the second housing are mechanically connected to each other, wherein the first housing and the second housing are both made of plastic and are fitted to each other. Along with matching, an annular conductive member is arranged along the entire circumference of the contact portion of both housings, and a high-frequency current is caused to flow in a conductive path arranged outside the both housings. A pressure switch characterized in that a conductive member is caused to generate heat to weld the first housing and the second housing.