JP3119074B2 - pressure switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure switch for sensing the pressure of a liquid or the like to open and close an electric contact, and is particularly suitable for use in a hydraulic circuit of a hydraulic brake system of an automobile braking system. Pressure switch.

[0002]

2. Description of the Related Art Japanese Utility Model Laid-Open No. 4-101338 shows an example of a conventional pressure switch used in a hydraulic circuit of a hydraulic brake system of an automobile braking system. The pressure switch includes a pressure detection unit A that detects a hydraulic pressure in the hydraulic circuit, and a switch unit B that is operated by the hydraulic pressure detected by the pressure detection unit A and opens and closes an electric circuit such as a hydraulic pump. Both are accommodated in a housing 1, and both A and B are partitioned by an inner lid 2.

The pressure detecting section A detects the pressure chamber 3 communicating with the hydraulic circuit via the pressure introducing path 3a, detects the hydraulic pressure in the pressure chamber 3, and connects the pressure chamber 3 and the switch section B to each other. , A stopper 5 for supporting the rear side of the diaphragm 4, a guide plate 6 for transmitting the deformation of the diaphragm 4 to the working disk 7, and elastically deformable to the switch portion B side by a hydraulic pressure acting on the diaphragm 4. The operating disk 7 is provided as a main part. The switch section B includes a switch 15 including a fixed bracket 16 and a movable bracket 17 attached to a base 18 fixed to the housing 1. The fixing bracket 16
It has a fixed contact 16a and is electrically connected to the connection terminal 19a, and the movable bracket 17 has a spring property.
A movable contact 17a that resiliently contacts the fixed contact 16a
And electrically connected to the connection terminal 19b.

A guide pin 12 for linking the pressure detecting section A and the switch section B is reciprocally held in a central through hole 2b of the inner cover 2, and a hydraulic pressure acting on the pressure detecting section A is provided. Exceeds a predetermined value, the central deformed portion 11 of the diaphragm 4 is deformed, and the working disk 7 is deformed via the guide plate 6 with this deformation, thereby moving the guide pin 12 to the switch portion B side. . As a result, the movable fitting 17 is elastically deformed, the movable contact 17a is separated from the fixed contact 16a, and the electric circuit of the hydraulic pump is opened. On the other hand, when the hydraulic pressure acting on the diaphragm 4 becomes equal to or less than the predetermined value, the central deformed portion 11 of the diaphragm 4 elastically returns to the original position again, whereby the movable bracket 17 also elastically returns while pressing the guide pin 12. Thus, the movable contact 17a comes into contact with the fixed contact 16a, and the electric circuit of the hydraulic pump is closed.

[0005]

In the pressure switch according to the above configuration, the diaphragm 4 has a function of shutting off the hydraulic circuit side and the switch section B side (external side of the hydraulic circuit) while maintaining the liquid tightness. Therefore, sufficient durability is required, but as described above, the circuit is repeatedly deformed by increasing and decreasing the pressure of the hydraulic circuit, and may be damaged by long-term use. When the internal diaphragm is damaged in this way, the hydraulic fluid in the hydraulic circuit leaks to the outside. The above-mentioned pressure switch is used, for example, for operating a motor of a hydraulic brake system of an automobile braking device, or for alarming. However, if hydraulic fluid leaks outside due to damage to a diaphragm, a braking force shortage occurs. There is a risk.

The present invention has been made to eliminate the above-mentioned drawbacks, and has a sealed structure and a sealed structure so that even if the diaphragm of the pressure sensing portion is broken, there is no danger of liquid leakage to the outside. It is another object of the present invention to provide a pressure switch which is easy to assemble and can reliably perform an electrical connection.

[0007]

A pressure switch according to the present invention accommodates a pressure sensor and a switch in a housing.
And the switch section side of the housing.
A metal case fixed to the opening of
Case and penetrated through this metal case and sealed with glass material
And a pair of pipe-shaped leads.
A pair of pins electrically connected to a pair of terminals
Insert each of the pipe-shaped leads into the pipe-shaped lead
While electrically connecting the pins to the pins,
The inside of the ip-shaped lead is sealed .

[0008]

In the pressure switch having the above structure, the housing,
A metal case with a lead sealed with a glass material was fixed via an O-ring to make the inside of the pressure switch completely liquid-tight, so the diaphragm of the pressure sensing unit was damaged, Even if the hydraulic fluid in the hydraulic circuit flows into the housing, it does not leak to the outside.

In order to completely prevent external leakage,
If the inside of the pressure switch is made to be a completely liquid-tight structure as described above, it is difficult to connect the terminal of the switch section to the lead sealed with a glass material in a metal case by a normal method. Since the pins are inserted into the leads, a housing accommodating the pressure sensing unit and the switch unit inside, and a metal case having a pipe-shaped lead sealed with a glass material are connected to the axis line. by fitting is moved in the direction, pie pins fixed to the terminal
It is possible to assemble it by a simple method of inserting it into a lead in the shape of a loop and electrically connecting and fixing the two outside the metal case.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings. FIG. 1 is a longitudinal sectional view of a pressure switch according to an embodiment of the present invention, in which a metal case 4 in which a housing 2 and a lead are sealed with a glass material, and a metal case 4 is interposed between the two. The pressure sensing unit 8 and the switch unit 10 are housed in a sealed container including the O-ring 6 mounted therein. The housing 2 has a cylindrical portion 2a, a pressure sensing portion 8 is provided on the bottom side (left side in FIG. 1) of the cylindrical portion 2a, and an opening of the cylindrical portion 2a is provided through an intermediate middle lid 12. The switch unit 10 is disposed on the side (the right side in FIG. 1, that is, on the side of the metal case 4 that blocks the inside of the housing 2).

The pressure sensing portion 8 is provided on the cylindrical portion 2 of the housing 2.
a, a film-shaped diaphragm 14 as a pressure-receiving member disposed in contact with the bottom surface of a, a stopper 16 for pressing the diaphragm 14 from the back side, and a concave portion 12 a formed on the stopper 16 side of the inner lid 12. Guide plate 18 movable in the axial direction of the lever pressure switch
A guide head 20 which is slidably fitted in a hole 16a at the center of the stopper 16 and moves integrally with the guide plate 18, and a disk interposed between the inner lid 12 and the guide plate 18. 22 and the like. A hydraulic pressure introduction passage 2b is formed in the housing 2, and a circular recess 2c is provided inside the housing of the hydraulic pressure introduction passage 2b, and a rubber diaphragm 24 is provided in the recess 2c.
Are arranged in close contact with the film-like diaphragm 14. The hydraulic pressure introduction passage 2b is connected to the hydraulic circuit of the hydraulic brake system of the vehicle braking device, and the pressure sensor 8 detects the hydraulic pressure in the hydraulic circuit. .

The disk 22 is formed of a disc spring that is protruded toward the guide plate 18 side, and an annular convex portion 18a formed on the end face of the guide plate 18 resiliently contacts a portion near the outer periphery thereof. I have. A circular hole 12a is formed in the center of the inner lid 12, and a guide pin 26 is slidably fitted in the circular hole 12a. When the disc 22 is in the free state shown in FIG. 1, the guide pin 26 is separated from the back side of the disc 22, and when the disc 22 is pushed by the guide plate 18 and elastically deforms rightward in FIG. The disk 22 is pushed by the disk 22 and moves toward the switch unit 10.

A base 28 is fitted into the opening of the housing 2, and the outer peripheral edge of the cylindrical portion 2 a of the housing 2 is caulked and fixed to the outer surface of the base 28. A switch unit 10 including a fixed terminal 30 and a movable terminal 32 is fixed to the inner surface of the base 28. The fixed terminal 30 includes a fixed contact 30a, and is electrically connected to one of the terminals extending outside the base.
The movable terminal 32 includes a leaf spring 32a. A movable contact 32b is attached to a tip end of the leaf spring 32a, and is electrically connected to one of the terminals 36 extending outside the base 28. The leaf spring 32a of the movable terminal 32
Normally, the movable contact 32b is brought into contact with the fixed contact 30a, and the diaphragm 14 as the pressure receiving member senses the liquid pressure and deforms.
When the guide pin 26 is moved rightward in the figure via the disk 8 and the disk 20, the guide pin 26 is pushed and deformed to separate the movable contact 32b from the fixed contact 30a.

A metal case 4 is mounted outside a base 28 fixed to the opening of the housing 2. The metal case 4 has an inner bottom surface and the housing 2.
The distal end portion 4a is fitted to the outer peripheral surface of the housing 2 in a state where there is a gap between the outer peripheral surface of the housing 28 and the outer surface of the base 28 fixed to the base 2. On the outer peripheral surface of the housing 2, an annular concave portion 2 is provided in the middle.
An O-ring 6 is fitted in the annular concave portion 2d. Housing 2
The distal end portion 4a of the metal case 4 fitted to the outer peripheral surface extends to a position beyond the annular convex portion 2e, and is fixed to the housing 2 by caulking the distal end portion 4a. The housing 2, the metal case 4 and the O-ring 6 form a sealed container.

At the bottom of the metal case 4, a pair of leads 40, 4 sealed between the metal case 4 and a glass material 38.
2 are inserted, and the inner ends 40a, 42a of the leads 40, 42 are electrically connected to the terminals 34, 36 provided on the outer surface of the base 28, and the outer ends 40b, 42b. 42b is electrically connected to external harnesses 44 and 46. Further, on the outside of the metal case 4,
The connector cover 70 is attached, and epoxy resins 72 and 7 are attached.
4 and the like. The above glass material 38
Have substantially the same coefficient of thermal expansion as the case 4 and the leads 40 and 42, thereby sealing between the case 4 and the leads 40 and 42.

The operation of the pressure switch according to the above configuration will be described. The hydraulic pressure in the hydraulic circuit of the hydraulic brake system is constantly acting on the pressure sensing portion 8 in the housing 2 via the hydraulic pressure introduction passage 2b, and when this hydraulic pressure reaches a predetermined value, The central portion of the diaphragm 14 as a pressure receiving member is deformed rightward in the drawing via the rubber diaphragm 24. The guide head 20 and the guide plate 18 are moved by the deformation of the diaphragm 14, and the disk 22 accommodated in the inner lid 12 is elastically deformed.
Due to the deformation of the disc 22, the guide pin 26 fitted in the hole 12a at the center of the inner lid 12 slides rightward in FIG. The leaf spring 32a of the movable terminal 32 is elastically deformed by the movement of the guide pin 26, and the movable contact 32b attached to the tip of the leaf spring 32a is separated from the fixed contact 30a of the fixed terminal 30 to turn off the switch.

When the hydraulic pressure in the hydraulic circuit drops below a predetermined value, the hydraulic pressure acts on the central portion of the diaphragm 14 as a pressure receiving member, and acts on the guide head 20 and the guide plate 18.
Is reduced, the disk 22 returns to its original shape by its own elasticity, and returns the diaphragm 14 to its original shape via the disk 22 and the guide plate 18. When the disk 22 returns to the original shape, the guide pin 26 pressed to the right in the figure is pushed back by the elasticity of the leaf spring 32a of the movable terminal 32, and the movable contact 32b contacts the fixed contact 30a to switch the switch. O
N.

In the above pressure switch, the inside of the housing 2 accommodating the pressure sensing portion 8 and the switch portion 10 is completely sealed by a metal case 4 sealed with a glass material between the lead and an O-ring 6. Because of the structure, the diaphragm 14 as the pressure receiving member and the rubber diaphragm 2
Even if 4 is damaged, the hydraulic fluid does not leak outside. Since the hydraulic brake system of the above-mentioned vehicle braking device is provided with the accumulator, the braking force does not immediately become insufficient and is safe.

The pressure switch according to the above embodiment has a completely sealed structure so that there is no danger of liquid leakage to the outside and high safety. However, the pressure switch is penetrated and fixed to the metal case 4 by the glass material 38. It is difficult to connect the leads 40 and 42 and the terminals 34 and 36 on the inner side. FIG. 2 shows a second embodiment in which the inside of the pressure switch has a completely hermetically sealed structure and can be easily assembled. In this embodiment, the configuration 10 of the pressure sensing unit 8 and the switch unit includes:
Since this embodiment is the same as the above embodiment, the same parts are denoted by the same reference numerals and description thereof will be omitted.

In this embodiment, the leads 50 and 51 fixed to the bottom of the metal case 4 via the glass material 38 are provided.
However, it has a pipe shape penetrating to both ends. On the other hand, pins 56 and 58 are fixed to the terminals 52 and 54 attached to the bottom of the base 28 by soldering, respectively. These pins 56 and 58 are provided near the bending portion 5 near the distal end.
6a and 58a are formed, and the curved portions 56a and 5a are formed.
8a are connected to the terminals 5b and 58b.
It is soldered so as to be orthogonal to 2,54.
Long linear portions 56c, 58 of these pins 56, 58
c is inserted into the pipe-shaped leads 50 and 51. The long linear portions 56c and 58c of the pipe-shaped leads 50 and 51 and the pins 56 and 58 have such lengths that the outer ends thereof are almost at the same position when inserted. (See FIG. 3). And these 50, 51,
56 and 58 the ends of, by welding by a method such as arc spot welding, as well as connecting them, pies
The liquid-tightness in the leads 50 and 51 is maintained. The pins 56, 58 soldered to the pair of terminals 52, 54 respectively have curved portions 56a, 58a.
Direction is reversed. Also, both pipe-shaped leads
Welded end of de 50 and 51, connectors 60 and 62
Are soldered to external harnesses 64 and 66, respectively.

The harnesses 64, 66 connected to the pair of pipe-shaped leads 50, 51 are inserted through holes 70a, 70b of a resin-made connector cover 70. The distal end of the resin connector cover 70 is fitted to the outer surface of the metal case 4, and the two 4 and 70 are bonded by a resin 72 such as epoxy. A connector cover 70 made of resin and a hole 7 of the connector cover 70 are provided.
0a, 70b, two harnesses 64,
66 is also bonded by an epoxy resin 74. In this embodiment, the diaphragm 14 is deformed to the right in the drawing upon sensing a fluid pressure exceeding a predetermined value, and the guide plate 18 and the guide head 20 are moved to move the disk 22.
When the guide pin 26 is moved by elastically deforming the movable contact 32b, the switch is turned off by separating the movable contact 32b from the fixed contact 30a as in the above-described embodiment. Movable contact 32b
Contacts the fixed contact 30a to turn on the switch.

The procedure for assembling the pressure switch according to the above configuration will be described. The rubber diaphragm 2 is placed in the cylindrical portion 2a of the housing 2 in order from the bottom side (left side in FIG. 2).
4. Diaphragm 14 as pressure receiving member, stopper 1
6. Insert the guide head 20, the guide plate 18, the disk 22, the inner lid 12, the guide pin 26, the base 28 to which the fixed terminal 30 and the movable terminal 32 are attached in order, and the like into the step 28a on the outer peripheral surface of the base 28. , Housing 2
Of the cylindrical portion 2a is fixed by caulking. The pins 56 and 58 are fixed to the pair of terminals 52 and 54 on the bottom outer surface side of the base 28 by soldering in advance.

[0023] A pair of pipe-shaped pipes having a glass material sealed between the metal case 4 and the case so as to penetrate the bottom surface of the metal case 4 .
The tips 4a of the metal case 4 are fitted from the opening side of the housing 2 while inserting the pins 56, 58 fixed to the terminals 52, 54 into the leads 50, 51, respectively. An annular convex portion 2e having an annular groove 2d at the center is formed on the outer peripheral surface of the cylindrical portion 2a of the housing 2, and an O-ring 6 is fitted in the annular groove 2d. The distal end 4a of the metal case 4 is projected forward (to the left in FIG. 2) from the annular convex portion 2e of the housing 2, and the projected distal end 4a is swaged, so that the housing 2 and the metal case 4 are integrated. , And these have a sealed structure. A pipe-shaped lead 50 protruding outside the metal case 4;
51, an outer end portion thereof and a pin 56 inserted therein.
58 and welded (see FIG. 3) to form a pipe-shaped lead.
To maintain the liquid-tightness and electrical connection in the nodes 50 and 51. Next, the pair of harnesses 64 and 66 inserted into the holes 70a and 70b of the connector cover 70 and the ends of the welded pipe-shaped leads 50 and 51 are soldered. Then, connect the connector cover 70 to the harness 6.
4, the metal case 4 is shifted. Adhesion between the metal case 4 and the connector cover 70 and between the connector cover 70 and both the harnesses 64 and 66 are performed by using resins 72 and 74 such as epoxy.

In this embodiment, the inside of the housing 2 is covered with a metal case 4 via an O-ring 6 to form a completely sealed structure, in which a pressure sensing unit 8 and a switch unit 10 are provided.
The hydraulic fluid in the hydraulic circuit leaks to the outside even if the diaphragm 14 and the rubber diaphragm 24 of the pressure sensing unit 8 that seals between the hydraulic circuit side and the inside of the pressure switch are damaged. Therefore, there is no possibility that the braking force of the hydraulic brake booster will be insufficient. Moreover,
In the first embodiment, the terminals 34 and 36 and the glass material 38 are used.
The lead 40 sealed in the metal case 4 by the
Although the connection work with 42 was difficult, in this embodiment,
The electrical connection can be made very simply and reliably. Although the leads 50 and 51 were formed into pipes, the outer ends of the leads 50 and 51 were welded and sealed.
A perfect liquid-tight structure can be obtained. And pin 5
The curved portions 56a, 58a are formed near the tip portions 56b, 58b to which the solders 6 and 58 are soldered, so that the slack is provided. And the connecting portion does not come off. In the second embodiment, the pins 56,
Tip portions 56b, 58 fixed to the terminals 52, 54 at 58
b and the linear portion 56 inserted into the leads 50 and 51
Although the curved portions 56a and 58a are provided between the pins 56 and 58c to allow room, the shape is not limited to the illustrated shape. For example, the pins 56 and 58 may be slackened by rotating the curved portions 56a and 58a once. You may give it.

FIG. 4 shows a modification of the second embodiment. In the second embodiment, the ends of pipe-like leads 50 and 51 penetrating through the metal case 4 via the glass material 38 are shown. The pipe-shaped lead 50,
Pa was adapted to seal the inside 51, in this embodiment, which is integrated between the metal case 4 are sealed with a glass material
The outer end 80a of the lead 80 has a bag shape from the beginning and is sealed inside. Therefore, pipe-shaped
It is not necessary to hold the fluid-tight sealed by welding the ends of the over de 80, after inserting the pin 82 into the pipe-like lead 80, by caulking the pipe-shaped lead 80 from the outside, the pipe Only the electrical connection between the lead 80 and the pin 82 is required. Therefore, the assembling process is further simplified as compared with the second embodiment.

[0026]

As described above, according to the present invention, in a pressure switch in which a pressure sensing unit and a switch unit are housed in a housing , the pressure switch on the switch unit side of the housing is provided.
A metal cable fixed to the opening to seal the switch
And this metal case was sealed with glass material
A pair of pipe-shaped leads, and
A pair of pins electrically connected to a pair of terminals are connected to the pair of pins.
Insert each of the pipe-shaped leads into the
Electrically connect the pins to the pins,
Since the inside of the housing becomes a completely sealed structure by sealing the inside of the reed-shaped lead , even if the diaphragm sealing the hydraulic circuit side and the inside of this pressure switch is broken, There is no possibility that the hydraulic fluid leaks to the outside.

Further, a lead whose glass is sealed between the case and the case is formed in a pipe shape, and pins fixed to the terminals of the switch section are inserted into the pipe-shaped lead . Since the pipe-shaped leads are electrically connected to each other and are fixed while maintaining liquid tightness, extremely simple and reliable connection can be achieved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a pressure switch according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a pressure switch according to a second embodiment.

FIG. 3 is an enlarged view of a main part of the embodiment in FIG. 2;

FIG. 4 shows an example in which a part of the embodiment of FIG. 2 is modified.
FIG.

[Explanation of symbols]

2 housing 4 metal case 6 O-ring 8 pressure sensing unit 10 switch unit 34 terminal 36 terminal 40 lead 42 lead 50 pipe-shaped lead 51 pipe-shaped lead 52 terminal 54 terminal 56 pin 58 pin

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoru Watanabe 2-11-6 Shinmeicho, Higashimatsuyama-shi, Saitama Automobile Equipment Co., Ltd. Matsuyama Plant (72) Inventor Norio Iida 2nd Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture Sun (72) Inventor Tetsuo Kimura 2nd Place, Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. (72) Inventor Masayuki Izawa 380 Tamate, Gosho-shi, Nara Wako Electronics Co., Ltd. 58) Field surveyed (Int.Cl. ⁷ , DB name) H01H 35/34

Claims (3)

(57) [Claims] 1. A pressure switch in which a pressure sensing unit and a switch unit are accommodated in a housing, wherein the pressure switch is fixed to an opening of the housing on the switch unit side.
A metal case to seal the switch
A pair of pipe-shaped pipes
And a pair of terminals of the switch unit.
A pair of pins connected to the inside of the pair of pipe-shaped leads
Respectively, and connect the pipe-shaped lead and the pin with each other.
While making electrical connections,
A pressure switch characterized by being sealed . 2. The metal case of the pipe-like lead.
More and outer tip, by welding the distal end portion of the inserted the pin into the pipe-shaped lead, the pipe
While electrically connecting the lead of the shape and the above-mentioned pin ,
2. The pressure switch according to claim 1, wherein the tip of the pipe-shaped lead is sealed. 3. The metal case of the pipe-shaped lead.
The outer tip is formed into a bag shape, and the pipe-shaped lead
Pressure switch according to claim 1 in which the pin of the soil by caulking a portion inserted, characterized in that electrically connecting the pipe-like lead and the pin.