JPH0117786Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a pressure switch that converts the movement of a diaphragm into reciprocating movement of a piston, which is applied, for example, to detect abnormalities in the brake hydraulic system of vehicles. .

(Prior Art) Conventionally, as this type of pressure switch, one shown in FIG. 3, for example, is known. According to this, a thin plate diaphragm 32 and a piston guide 33 whose upper end surface 33a is in contact with the diaphragm 32 are arranged in a cylindrical upper case 30 and a lower case 31 fitted therein, and the piston An insertion hole 33b is formed in the center of the guide 33, and a piston 34 whose upper end abuts the diaphragm 32 is inserted into the insertion hole 33b so as to be able to freely slide in the direction through the hole. The lower end of the piston 34 is in contact with a pressure receiving plate 35 whose upper end surface 35a is in contact with the lower end surface 33c of the piston guide 33. The lower end surface 35a of the pressure receiving plate 35 is in contact with the pressure receiving plate 35.
A coil spring 36 applies upward spring pressure to the
The lower end of the coil spring 36 is in contact with the bottom surface of the lower case 31. Further, a coil spring 3 is provided below the pressure receiving plate 35.
A limit switch 37 is disposed inside 6,
An upwardly projecting operator 37a of the limit switch 37 is in contact with a lower end surface 35b of the pressure receiving plate 35.

In the pressure switch configured in this way, the hydraulic pressure F applied to the diaphragm 32 is applied to the coil spring 3.
When the spring pressure of 6 is exceeded, the center portion 32a of the diaphragm 32 moves toward the piston guide 33 as shown in FIG.
The piston 34 is depressed into the insertion hole 33b, and the piston 34 is moved downward, and the operator 37a is pressed to turn on the limit switch 37, so that abnormalities in the hydraulic pressure can be detected.

(Problem to be Solved by the Invention) However, according to the configuration of the prior art, the limit switch 37 and the like are housed in two upper and lower separable cases 30 and 31. On the other hand, if the diaphragm 32 is made thick to increase its pressure resistance, for example, the diaphragm 32
The interaction between the diaphragm 32 and the piston 34 may damage the diaphragm 32, and since it is composed of two cases, it may be difficult to withstand high internal pressure or external impact. There is a problem with sexuality.

Further, when the limit switch 37 and the like are assembled, these members are assembled to the upper and lower two cases 30 and 31, so that there is a problem in terms of ease of assembly.

(Means for Solving the Problems) The present invention was made in view of the problems of the prior art described above, and converts the movement of a diaphragm that deforms when the pressure exceeds a predetermined spring pressure into the reciprocating movement of a piston. In a diaphragm pressure switch that operates a limit switch and detects pressure changes,
A substantially cylindrical single case, a substantially bowl-shaped thick-walled diaphragm disposed on the pressure introduction side of the case, and an integrally molded diaphragm at the center of the inner bottom surface of the diaphragm, which contacts one end of the piston. a piston receiving plate in contact with the piston receiving plate; a first pressure receiving plate through which the piston freely passes through a hole formed in the center and facing the diaphragm and regulating the amount of movement of the piston receiving plate; and the first pressure receiving plate. a second pressure receiving plate disposed opposite to the other end of the piston and fitted with the other end of the piston;
a coil spring interposed between the pressure receiving plate and the bottom side end of the case and pressing the second pressure receiving plate against the first pressure receiving plate with a predetermined spring pressure; and a coil spring facing the second pressure receiving plate. The movable contact portion is arranged in the second
A limit switch that comes into contact with the second pressure receiving plate; and a holder that is attached to close the opening on the bottom side of the case to hold the limit switch and adjust its position relative to the second pressure receiving plate, and is durable. The present invention aims to provide a pressure switch that can improve robustness, ease of assembly, etc.

(Function) To assemble the pressure switch, a thick diaphragm on which a piston receiving plate is molded, a first pressure receiving plate,
The second pressure receiving plate to which the piston is fitted, the coil spring, and the holder to which the limit switch is attached are housed in order. In the pressure switch assembled in this manner, for example, when the pressure introduced from the hydraulic system exceeds the spring pressure of the coil spring, the thick diaphragm deforms, the piston moves downward, and the limit switch is turned on, thereby detecting an abnormality in the hydraulic system.

(Example) An example of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a longitudinal cross-sectional view of a diaphragm pressure switch according to the present invention. Inside a cylindrical single case 2 of the pressure switch 1, there are holes 2a, 2b, 2c,
are drilled concentrically and in steps, and the hole 2
An annular groove 2d having a semicircular cross section is formed on the peripheral edge of the bottom end surface 2e of b, and a threaded portion 2g is carved on the upper end 2f. The case 2 having such a shape is integrally formed of a metal member having pressure resistance and heat resistance. The diaphragm 3 is thick-walled and approximately bowl-shaped, and an annular protrusion 3a having a semicircular cross section is formed at the periphery of the bottom end surface 3e, and the center of the bottom surface of the hole 3c formed at the center of the end surface 3b. A concentric hole 3d is formed in the hole 3d. The diaphragm 3 having such a shape is integrally formed of a rubber member. This diaphragm 3 is fitted into the hole 2b of the case 2, the annular protrusion 3a is fitted into the groove 2d, and the end surface 3e is in contact with the bottom surface 2e of the hole 2b.

The piston receiving plate 4 is integrally attached to the diaphragm 3 by molding in the hole 3d of the diaphragm 3, and a hole 4b is provided at the center of the end surface 4a. This piston receiving plate 4 is formed of a metal member. The pressure receiving plate 5 is fitted into the hole 2c, and has a hole 5a in the center, and the peripheral edge 5c of the hole 5a bulges toward the end surface 5b to form a stopper, and is loosely fitted into the hole 3c of the diaphragm 3. and
Its end surface 5d faces the end surface 4a of the piston receiving plate 4 at a predetermined distance, and its end surface 5b faces the diaphragm 3.
It is in contact with the end surface 3b of. This pressure receiving plate 5 is also formed of a metal member.

The cylindrical stopper 6 is press-fitted into the hole 2c and holds the pressure receiving plate 5 in this position. A hole 9a and a screw hole 9b are concentrically formed in the center of the holding plate 9, and are press-fitted into the hole 2c of the case 2. A liquid-tight O-ring 10 is installed in an annular groove 9c formed along the circumferential direction on the circumferential surface of the holding plate 9. These stopper 6 and holding plate 9 are also formed of metal members.

The pressure receiving plate 7 is loosely fitted into the stopper 6 so as to be movable in the axial direction, and a hole 7b is bored in the center of the end surface 7a. This pressure receiving plate 7 is also formed of a metal member. The piston 8 passes freely through the hole 5a of the pressure receiving plate 5, one end of which is loosely fitted into the hole 4b of the piston receiving plate 4, and the other end is press-fitted into the hole 7b of the pressure receiving plate 7. The coil spring 11 is loosely fitted in the stopper 6 in the axial direction, one end of which engages with a notch 7d formed in the peripheral edge of the pressure receiving plate 7, and the other end of which is in contact with the retaining plate 9, so that the coil spring 11 can be moved with a predetermined spring pressure. End surface 5e of pressure receiving plate 5
The opposite end surface 7c of the pressure receiving plate 7 is pressed against the opposite end surface 7c of the pressure receiving plate 7.

The holder 12 for holding the limit switch has a cylindrical shape, and a screw hole 9 of the holding plate 9 is provided on the peripheral surface of one end of the holder 12.
A threaded portion 12a is formed to be screwed into the shaft, and a square hole 12b is bored in the shaft center. The holder 12 is made of a synthetic resin member. This holder 12 is screwed into a screw hole 9b of the holding plate 9, and an operator 13a that drives a movable contact portion of a limit switch 13 mounted in the hole 12b of this holder 12 is connected to an opposite end surface 7a of the pressure receiving plate 7. is in contact with. Operator 13a of this limit switch 13
The distance between the holder 12 and the opposing end surface 7a of the pressure receiving plate 7 is adjusted to an optimal position by the screwing position of the holder 12 to the holding plate 9.

Each end 20a, 21a of the connection cord 20, 21
is inserted into the hole 12b of the holder 12 from the outside of the case 2, and the connection terminal 13 of the limit switch 13 is inserted into the hole 12b of the holder 12 from the outside of the case 2.
b and 13c by soldering. A rubber plug 14 for sealing is press-fitted into the hole 9a of the holding plate 9 and the hole 12b of the holder 12, and the cords 20, 2 are pressed into place.
1, and also protects the connection between these cords 20, 21 and the limit switch 13 and the inside of the case 2 in a liquid-tight manner. Further, a plate 15 is press-fitted onto the outside of the rubber stopper 14, and is caulked by the open end 2h of the case 2. Each of the cords 20 and 21 is inserted through a hole 15a of the plate 15 and led out of the case 2.

In this way, the diaphragm pressure switch 1
A threaded portion 2g carved on the circumferential surface of one end 2f of the case 2 is screwed into, for example, a hydraulic circuit (not shown), and each cord 20, 21 is connected to an abnormality detection device (not shown) for the hydraulic circuit. Connect to.

In this configuration, when the oil pressure in the hydraulic circuit is in a normal state, the coil spring 11 pushes up the piston 8 against the oil pressure F applied to the end surface 3e of the diaphragm 3, as shown in FIG. The pressure receiving end surface 3e of the diaphragm 3 is pressed against the bottom surface 2e of the hole 2b of the case 2. In this state, the operator 13a of the limit switch 13 is protruded by the spring force as shown in the figure, and the switch is turned off.

When an abnormality occurs in the hydraulic circuit and the hydraulic pressure F applied to the end surface 3e of the diaphragm 3 increases and exceeds the spring force of the coil spring 11, the end surface 3e of the diaphragm 3 moves against the annular protrusion 3a as shown in FIG. It curves as a fulcrum and pushes the piston 8 and pressure receiving plate 7 downward in the figure via the piston receiving plate 4. The piston receiving plate 4 is pushed down until the end surface 4a abuts and is locked against the opposing end surface 5d of the stopper portion 5c of the pressure receiving plate 5. As the pressure receiving plate 7 moves downward, the operator 13a of the limit switch 13 is pressed and recessed into the case of the limit switch 13, and the switch is turned off when the pressure receiving plate 7 is locked at the position shown.

As shown in FIG. 2, the entire end face 3e of the diaphragm 3 is curved around the annular protrusion 3a as a fulcrum, so that the stress generated during the bending is not concentrated in a specific location, and it is thick. Because of this, it is strong, and furthermore, because the piston 8 is pressed through the piston receiving plate 4, it is difficult to tear. That is, the durability of the diaphragm 3 is improved.

As described above, according to the present invention, the diaphragm pressure switch converts the movement of the diaphragm that deforms when the pressure exceeds a predetermined spring pressure into the reciprocating movement of the piston to operate the limit switch and detect the pressure change. A single cylindrical case, a substantially bowl-shaped thick-walled diaphragm disposed on the pressure introduction side within the case, and integrally molded at the center of the inner bottom surface of the diaphragm and abuts one end of the piston. a piston receiving plate; a first pressure receiving plate through which the piston freely passes through a hole formed in the center of the diaphragm and facing the diaphragm; and the first pressure receiving plate; The second end is disposed opposite to the other end of the piston and is fitted with the other end of the piston.
a coil spring that is interposed between the second pressure receiving plate and the bottom end of the case and presses the second pressure receiving plate against the first pressure receiving plate with a predetermined spring pressure; a limit switch disposed opposite to the second pressure receiving plate and having a movable contact portion abutting the second pressure receiving plate; and a limit switch mounted to close the bottom opening of the case to hold the limit switch and the second pressure receiving plate. Since the structure is equipped with a holder that adjusts the position relative to the plate, durability will not be compromised even if the diaphragm is made thick.In addition, by housing the switch components in a single case, internal It can sufficiently withstand external shocks and has an improved appearance of simplicity. In addition, the diaphragm, the first and second pressure receiving plates, etc. can be easily assembled one after another into the case, improving the ease of assembly. Furthermore, since the limit switch can be attached to the holder in an adjustable manner, the accuracy of attachment during assembly can be relaxed without compromising robustness.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the diaphragm pressure switch according to the present invention, FIG. 2 is a longitudinal sectional view illustrating the operation of the diaphragm pressure switch shown in FIG. 1, and FIGS. The figures show a conventional pressure switch, FIG. 3 is a vertical cross-sectional view showing its overall configuration, and FIG. 4 is a vertical cross-sectional view explaining its operation. DESCRIPTION OF SYMBOLS 1... Pressure switch, 2... Case, 3... Diaphragm, 4... Piston receiving plate, 5... First pressure receiving plate, 7... Second pressure receiving plate, 6... Stopper,
8... Piston, 12... Holder, 13... Limit switch.

Claims (1)

[Scope of utility model registration request] A diaphragm pressure switch that converts the movement of a diaphragm that deforms when pressure exceeds a predetermined spring pressure into reciprocating motion of a piston to operate a limit switch and detect a pressure change, includes a substantially cylindrical single case and the case. a substantially bowl-shaped thick-walled diaphragm disposed on the pressure introduction side of the diaphragm; a piston receiving plate integrally molded at the center of the inner bottom surface of the diaphragm and abutting one end of the piston;
a first pressure receiving plate, through which the piston freely passes through a hole formed in the center and arranged opposite to the diaphragm, and regulating the amount of movement of the piston receiving plate;
a second pressure receiving plate disposed opposite to the pressure receiving plate and to which the other end of the piston is fitted; a second pressure receiving plate interposed between the second pressure receiving plate and the bottom end of the case;
a coil spring that presses the second pressure receiving plate against the pressure receiving plate with a predetermined spring pressure; a limit switch disposed opposite to the second pressure receiving plate and having a movable contact portion abutting the second pressure receiving plate; A diaphragm pressure switch comprising: a holder attached to close a bottom opening of a case to hold the limit switch and adjust its position relative to the second pressure receiving plate.