JPH0715420B2 - Pressure sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a pressure sensor. More specifically, the force of fluid pressure is antagonized with the biasing force of a coil spring through a diaphragm member.
The present invention relates to a pressure sensor that moves a movable-side electrode of an electric signal output unit including a sliding switch and a variable resistor by a diaphragm member that is displaced according to the pressure of the fluid.

[Prior Art] Conventionally, as a pressure sensor of this type, for example, a force generated by the pressure of hydraulic oil is antagonized with an urging force of a coil spring through a diaphragm, and a displacement generated in the diaphragm is used in a separate chamber link mechanism. There is one in which the displacement is enlarged by a displacement enlargement mechanism to move the movable electrode of the slide resistor, and the resistance value is changed according to the pressure of the hydraulic oil. This pressure sensor is used to detect the pressure of the hydraulic system of the vehicle, and controls the pressure indicator provided on the panel inside the vehicle according to the change of the resistance value to display the pressure of the hydraulic system.

[Problems to be Solved by the Invention] However, the above-described conventional pressure sensor has a problem in that the displacement enlargement mechanism needs to be housed inside and a movable space is required, and an increase in volume cannot be avoided. Therefore,
For example, when mounted on a vehicle with a limited installation space, inconvenience may occur. Further, since the displacement magnifying mechanism is used, the number of parts is increased, the number of assembling steps is increased, and the parts management is complicated.

Furthermore, in the conventional pressure sensor, if a plurality of electric signal output parts such as slide resistors and switches are to be housed, the structure of the displacement magnifying mechanism becomes more complicated, and the displacement of the diaphragm is output by each electric signal output part. There is a problem that the number of parts and the number of assembling steps are further increased.

An object of the pressure sensor of the present invention is to solve the above-mentioned problems and to downsize the sensor and simplify the manufacturing process.

Configuration of the Invention The configuration of the present invention that achieves the above object will be described below.

[Means for Solving the Problems] In the pressure sensor of the present invention, the force due to the pressure of the fluid is antagonized with the urging force of the coil spring through the diaphragm member, and the diaphragm member is displaced according to the pressure of the fluid. In a pressure sensor that moves a movable-side electrode of an electric signal output unit including a dynamic switch and a variable resistor, the diaphragm member forms a tubular flexible portion on an outer periphery of a pressure receiving surface along a displacement direction. An actuating piece having the movable side electrode at the other end is brought into contact with a surface of the diaphragm member on the coil spring side, and an electric signal output section including the switch and the variable resistor is connected to the coil spring side of the diaphragm member. And the inner surface of the coil spring.

[Operation] In the pressure sensor of the present invention having the above configuration, the force due to the fluid pressure opposes the urging force of the coil spring via the diaphragm member, and the diaphragm member is displaced according to the fluid pressure. Since the displacement amount of the diaphragm member having the flexible portion on the outer circumference of the pressure receiving surface is large,
Converts fluid pressure changes into large displacements. Due to the change in the diaphragm member, the operating piece provided with the movable electrode is moved.
On the other hand, an electric signal output part such as a sliding switch and a variable resistor whose output changes according to the movement of the movable side electrode of the operating piece is composed of a coil spring side surface of the diaphragm member and an inner side surface of the coil spring. It is stored in a room. Therefore, without increasing the size of the pressure sensor, the movement of the movable electrode can be increased, and the electric signal output such as the on / off signal of the switch and the resistance value of the variable resistor can be taken out according to the fluid pressure.

[Examples] In order to further clarify the configuration and operation of the present invention described above, preferred examples of the pressure sensor of the present invention will be described below.

A pressure sensor as an embodiment of the present invention is used to detect the pressure of a hydraulic system of a vehicle. With this pressure sensor,
As shown in the cross section in FIG. 1, a diaphragm member 5 for blocking hydraulic oil is attached between a base 1 connected to a hydraulic oil pipe and a main body storage portion 3 fixed to the upper end of the base 1. . A coil spring 13 that produces a biasing force that opposes the force due to the pressure of the hydraulic oil via the diaphragm member 5 is housed in the main body housing portion 3. On the diaphragm member 5 in the main body storage part 3,
Sliding switch 7 and movable electrode 11 of variable resistor 9
A movable plate 11 including a and 11b is provided. The switch 7 and the variable resistor 9 are attached to the lower surface of the connection terminal member 15 fixed to the upper end of the main body housing portion 3, and are connected to the coil spring.
It is housed in a chamber 16 formed inside 13.

The base 1 has an inlet 1a for hydraulic oil. The base 1 and the main body housing 3 are both configured as an electric conductor (made of metal) and are electrically connected to each other.

The diaphragm member 5 has, around the pressure receiving surface 5a formed in the center thereof, a cylindrical flexible portion 5b which moves up and down the pressure receiving surface 5a. As a material of the diaphragm member 5, a resin material or the like that does not deteriorate due to hydraulic oil is used. For attachment, the peripheral edge portion 5c of the diaphragm member 5 is sandwiched between the upper surface of the base 1 and the flange portion 17a of the pressing member 17, and the outer edge of the base 1 is attached to the flange of the main body storage portion 3 from above the flange portion 17a. It is made strong by caulking.

The movable plate 11 is configured as an electric conductor (made of metal), and has contacts (movable electrodes) 11a and 11b at the other end that slightly project toward the switch 7 and the variable resistor 9. The movable plate 11 is attached by welding, soldering, or the like to a supporting member 19 that abuts on the surface of the diaphragm member 5 opposite to the pressure receiving surface 5a, and is electrically connected to the supporting member 19.

The supporting member 19 is made of a thin metal plate, and is entirely configured as an electric conductor. The support member 19 is a cylindrical body having a bottom surface of the same size as the pressure receiving surface 5a of the diaphragm member 5, and further has a large-diameter cylindrical portion 19a extending from the upper portion of the cylindrical body and a large-diameter cylinder. A brim portion 19b formed at the lower end of the portion 19a is provided. The large-diameter cylindrical portion 19a is located outside the cylindrical portion 17b formed on the pressing member 17 for the diaphragm member 5,
The support member 19 constitutes a guide for moving up and down.

The coil spring 13 is a compression spring made of metal and has a small spring constant. The lower end of this coil spring 13 is
The support member 19 is supported by the outer circumference of the large-diameter cylindrical portion 19a and the collar portion 19b. Thereby, conduction between the coil spring 13 and the support member 19 is also achieved. The upper end portion of the coil spring 13 is supported by the flange portion 21a of the annular member 21 that abuts the lower surface of the connection terminal member 15. The annular member 21 is configured as an electric conductor (made of metal), and is fixed to the inner peripheral surface of the main body accommodating portion 3 by welding, caulking or the like. Therefore, the movable plate 11 is
Through the support member 19, the coil spring 13, and the annular member 21, the main body storage portion 3 and the base 1 are electrically connected, and thus connected to the ground.

The connection terminal member 15 is made of an insulating resin material,
A connection portion 15a for connecting to an external pressure indicator or the like is formed on the upper end. The fixed side electrodes 23a and 23b of the switch 7 and the variable resistor 9 are provided to be exposed inside the connection portion 15a.

The switch 7 and the variable resistor 9 form wirings, terminal portions, resistor portions, etc. by printing conductive ink and resistor ink such as cermet on one insulating plate 25 made of ceramic or the like. By combining these, a sliding switch and a variable resistor are configured.

As shown in the enlarged view of FIG. 2, the variable resistor 9 has a resistor portion 27 formed in a long axis shape. The width of the resistor portion 27 is changed along the major axis direction. The end portion 27a of the resistor portion 27 on the diaphragm member 5 side is connected to the fixed side electrode 23b by a wiring 29 of an electric conductor. From the side portion 27b to the side portion 27b in the long axis direction of the resistor portion 27,
31a are provided in parallel at a small interval, and the multistage terminal portion 31
Is formed.

The switch 7 is one in which the wiring of the electric conductor connected to the fixed electrode 23a is extended to the vicinity of the end of the insulator 25 on the diaphragm member 5 side, and the terminal portion 33 is provided. Like the multi-stage terminal portion 31 of the variable resistor 9, a multi-stage contact portion 35 in which the terminal strips 35a are arranged in parallel is provided above the terminal portion 33 of the switch 7. The switch-side multistage contact portion 35 is not electrically connected to any of them.

In the pressure sensor of the embodiment thus configured, the pressure of the hydraulic oil acting on the pressure receiving surface 5a of the diaphragm member 5 causes
Through the support member 11, the coil spring 13 contracts to a position where it opposes the force due to the pressure of the hydraulic oil. Along with this, the pressure receiving surface 5a of the diaphragm member 5 also moves. Since the spring constant of the coil spring 13 is small and the diaphragm member 5 has the flexible portion 5b, the pressure receiving surface 5a of the diaphragm member 5 is changed by the pressure change of the hydraulic oil.
Large displacement.

Thus, when the pressure receiving surface 5a of the diaphragm member 5 is displaced according to the pressure of the hydraulic oil, the movable plate 11 on the support member 19 is moved along with the displacement, and the contacts 11a, 11b of the movable plate 11 are moved.
Moves on the terminal portions 33, 35 of the switch 7 and the terminal portion 31 of the variable resistor 9. This allows the ground and fixed side electrodes
Depending on the pressure of the hydraulic oil, the switch 7 is provided between 23a and 23b.
The on / off signal and the resistance value of the variable resistor 9 are obtained.

The resistance value of the variable resistor 9 at this time is determined by the distance between the end portion 27a of the resistor portion 27 connected to the fixed side electrode 23b and the contact point 11b of the movable plate 11. In the embodiment, if the pressure of the hydraulic oil is high, the resistance value is high, and if the pressure is low, the resistance value is low. On the other hand, the output of the switch 7 at this time remains open, that is, an OFF signal while the contact point 11a of the movable plate 11 moves on the multistage contact portion 35 because the pressure of the hydraulic oil is equal to or higher than a predetermined value. Become. On the other hand, when the pressure of the hydraulic oil decreases to a predetermined value or less, the displacement amount of the diaphragm member 5 decreases, and the contact point of the movable plate 11 decreases.
Since 11a is connected to the terminal portion 33 of the switch 7, the output of the switch 7 becomes an ON signal.

In the pressure sensor of the embodiment described above, the switch 7 and the variable resistor 9 are housed in the chamber 16 formed inside the coil spring 13, and the movable plate 11 having the contacts 11a and 11b as the movable side electrodes thereof is separated by the diaphragm. By contacting the member 5,
Since the movable plate 11 is directly moved by the diaphragm member 5 to change the outputs of the sliding switch 7 and the variable resistor 9, the volume is reduced and the number of parts is reduced. It has an excellent effect of decreasing the number. Therefore, even when it is installed in a vehicle with a limited installation space, the conventional inconvenience does not occur.

Further, in the pressure sensor of the embodiment, since the switch 7 and the variable resistor 9 are provided in parallel on the same insulating plate 25, the switch 7 and the variable resistor 9 can be displaced in the diaphragm member 5 only by widening the movable plate 11. The output of the variable resistor 9 can be surely corresponded, and the number of parts does not increase even if the switch 7 and the variable resistor 9 are used together. The switch 7 and the variable resistor 9 may be formed as a cylindrical insulating member.

Further, the variable resistor 9 is provided above the terminal portion 33 of the switch 7.
By providing the multi-stage contact portion 35 having the same shape as the multi-stage terminal portion 31 of FIG.
Since the relationship between the output of the variable resistor 9 and the output of the variable resistor 9 is not impaired, wear due to contact between the insulating plate 25 and the contact 11a can be prevented, and reliability is improved.

Since the variable resistor 9 of the embodiment has the resistor portion 27 formed on the surface of the insulating plate 25 by printing or the like, the width of the resistor portion 27 is shown in FIG. In addition to the shapes shown, various changes can be made to make the relationship between the hydraulic pressure and the resistance value a desired characteristic.

EFFECTS OF THE INVENTION As described in detail above, in the pressure sensor of the present invention, the electric signal output portion including the switch and the variable resistor is housed in the chamber formed inside the coil spring, and the movable electrode of the electric signal output portion is provided. The operating piece provided is brought into contact with a diaphragm member having a tubular flexible portion, and the diaphragm member directly moves the movable electrode to change the output of the electric signal output unit. That is, the pressure sensor of the present invention has an excellent effect that the volume is reduced and the number of parts is reduced by such an extremely simple configuration. Therefore, according to the pressure sensor of the present invention, there is no need for a storage space for the displacement magnifying mechanism and a movable space as in the conventional case, the volume can be significantly reduced, and the number of parts is small, so that the number of assembly steps is reduced The number can be significantly reduced and the parts management can be facilitated. Further, since the number of movable parts is small, the reliability can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a pressure sensor according to an embodiment of the present invention, and FIG. 2 is a partially enlarged view showing a switch and a variable resistor thereof. 5 ... Diaphragm member, 7 ... Switch 9 ... Variable resistor 11 ... Movable plate corresponding to operating piece 13 ... Coil spring

Claims (1)

[Claims] Claim: What is claimed is: 1. An electric device comprising a sliding type switch and a variable resistor, wherein a force due to the pressure of fluid is counteracted with an urging force of a coil spring through the diaphragm member, and the diaphragm member is displaced according to the pressure of the fluid. In the pressure sensor that moves the movable electrode of the signal output unit, the diaphragm member has a cylindrical flexible portion formed on the outer periphery of the pressure receiving surface along the displacement direction, and the surface of the diaphragm member on the coil spring side. Abutting an actuating piece having the movable side electrode at the other end thereof, and an electric signal output section including the switch and the variable resistor is provided by a coil spring side surface of the diaphragm member and an inner side surface of the coil spring. A pressure sensor characterized by being housed in a configured chamber.