JPH062188U - Oil pressure sensor - Google Patents

Abstract

(57) [Summary] [Purpose] Contact failure does not occur even after long-term use,
An object of the present invention is to provide a hydraulic pressure sensor that can accurately detect hydraulic pressure. [Structure] An inner surface side of a diaphragm 5 which receives a hydraulic pressure on an outer surface is arranged so as to face an airtight chamber 20 which is airtightly sealed to the outside, and a displacement amount of the diaphragm 5 caused by a change in the hydraulic pressure is detected. In order to achieve this, in the hydraulic sensor in which the detection means 2 having the contact point 22a that moves following the displacement of the diaphragm 5 is provided in the airtight chamber 20, at least a part of the airtight wall forming the airtight chamber 20 is expanded. The airtight chamber 20 was filled with oil while being formed by the elastic wall 18 which was capable of contracting.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a hydraulic pressure sensor for detecting the pressure of automobile engine oil or the like.

[0002]

[Prior art]

 This type of oil pressure sensor has a potentiometer, etc., which has an electric contact that moves following the displacement of the diaphragm, on the inner surface of the diaphragm in order to detect the displacement of the diaphragm that receives the oil pressure on the outer surface. .

[0003]

[Problems to be solved by the device]

 If the movement of the electrical contact while making contact with the electrical resistance of the potentiometer is repeated as the hydraulic pressure fluctuates, abrasion powder is generated from the contact portion.

Then, if the abrasion powder adheres to the contact portion, contact failure of the electric contact occurs, and the output signal of the potentiometer is distorted so that the correct hydraulic pressure cannot be detected.

Therefore, an object of the present invention is to provide a hydraulic pressure sensor that can correctly detect hydraulic pressure without causing contact failure due to abrasion powder even after long-term use.

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the oil pressure sensor of the present invention is arranged so that the inner surface side of the diaphragm, which receives the oil pressure on the outer surface, faces the airtight chamber that is hermetically sealed from the outside. In order to detect the displacement amount of the diaphragm caused by the above, in a hydraulic sensor provided with a detection means having a contact point that moves following the displacement of the diaphragm in the airtight chamber, at least one of the airtight walls forming the airtight chamber is provided. It is characterized in that the portion is formed by an elastic wall that can expand and contract, and that the airtight chamber is filled with oil.

[0007]

[Action]

 The abrasion powder generated from the contact portion of the contact is made to flow and diffuse by the oil filled in the airtight chamber surrounding it, and does not remain at the contact portion of the contact. In addition, the elastic wall expands and contracts as the volume of oil produced by heat changes, and the pressure in the airtight chamber hardly changes due to heat, so correct pressure detection is performed.

[0008]

【Example】

 Embodiments will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a metal connection body whose front side is screwed into an engine oil chamber of an automobile, and a metal base 3 on which a potentiometer 2 is erected on the rear side is caulked at a base side thereof. It is fixed.

A diaphragm chamber 4 is formed between the connection body 1 and the base 3, and the diaphragm chamber 4 is partitioned by a diaphragm 5 made of a flexible thin film which can be displaced in a direction perpendicular to the plane. ing.

A communication hole 7 is formed between the tip of the connection body 1 and the diaphragm chamber 4, and the oil pressure of the engine oil passes through the communication hole 7 to the outside of the diaphragm 5. It is designed to join the surface. 8 is a sealing O-ring, 9 is a receiving plate for receiving the diaphragm 5, and a hole is formed in the center.

A short rod 11 whose one end abuts on the central portion of the inner surface of the diaphragm 5 is slidably arranged in the center hole of the base 3. Further, a rotating plate 12 as shown in FIG. 2 is rotatably supported at both ends on the surface on the opposite side of the base 3 when viewed from the diaphragm 5 side.

A protrusion 14 that abuts on the end face of the rod 11 is provided at the center of the rotating plate 12, and the protrusion 14 is pressed against the end face of the rod 11 at one end of the rotating plate 12. A spring 16 for urging the rotating plate 12 in the direction is attached.

As described above, the rotary plate 12 receives the force of the diaphragm 5 pressed by the hydraulic pressure via the rod 11 and the protrusion 14, and receives the force in the opposite direction from the spring 16 to balance the two forces. Stationary in position.

A brush 22 that is in contact with a resistance (electrical resistance) row 21 of the potentiometer 2 is fixed to the other end of the rotating plate 12. Therefore, when the hydraulic pressure changes, the diaphragm 5 is displaced accordingly, and the brush 22 is rotated together with the rotary plate 12 which is rotated following the displacement.

As a result, when the contact position of the electrical contact 22a at the tip of the brush 22 changes with respect to the resistance row 21, the potential of the lead wire 23 drawn out from the resistance row 21 changes, and the hydraulic pressure is changed from that potential. Can be detected.

Reference numeral 25 shown in FIGS. 1 and 2 is a semi-circular earth made of a thin leaf spring material, one end of which is sandwiched between the brush 22 and the rotary plate 12 in order to body-earth the brush 22. It is a lead, and the other end side is fixedly connected to the base 3 by caulking.

As described above, when the ground lead 25 is caulked on the base 3 by using a thin leaf spring, soldering work is not required for connection, and the posture is stable because it does not fluctuate like a stranded wire. The assembly workability is very good.

On the rear surface side of the base 3 on which such a mechanism is arranged, as shown in FIG. 3, an inner cap 17 made of plastic and formed in conformity with the shapes of the rotating plate 12 and the potentiometer 2 is provided. It is covered.

An inflatable and deflatable rubber cap 18 made of rubber is put on the outside of the inner cap 17 in a state of completely sealing the outside air, and the inside thereof is kept in the airtight chamber 20. Is formed. Further, a cylindrical outer cap 19 made of plastic or metal is covered on the outer side thereof.

The outer cap 19 firmly fixes the inner cap 17 and the rubber cap 18, and sandwiches the end of the rubber cap 18 so that the rubber cap 18 completely seals the inside of the apparatus from the outside air. It is fixed to the connection body 1 side by caulking.

As shown in FIG. 1, there is a gap 30 in the lower portion of the inner cap 17 which communicates with the rubber cap 18, and the outer cap 19 has a vent hole 31 as shown in FIG. Has been drilled. Therefore, the rubber cap 18 forms an airtight wall, but the inner and outer caps 17 and 19 do not. Reference numerals 32, 33 and 34 are through holes formed in the caps 17, 18 and 19 for inserting the lead wires 23.

As shown in FIG. 3, the rubber cap 18 is formed with a convex portion 18 a that partitions the space between the inner and outer caps 17, 19 into about half. Therefore, the rubber cap 18 can freely expand and contract between the outer surface of the inner cap 17 and the inner surface of the outer cap 19 at the convex portion 18a.

In this way, the airtight chamber 20 formed with the rubber cap 18 as the airtight wall is filled with so-called contact oil made of electrically insulating silicon-based oil, and the air is filled with air. It is completely excluded from within 20. The inner surface side of the diaphragm 5 faces the airtight chamber 20 filled with this contact oil.

Therefore, even if abrasion powder is generated from the contact portion by repeating the operation of moving the electrical contact 22a while contacting the resistance row 21 of the potentiometer 2 with the fluctuation of the hydraulic pressure, even if the abrasion powder is generated. Is quickly washed away by the contact oil and diffuses, leaving no contact.

When this oil pressure sensor is attached to the engine oil chamber of an automobile, the surrounding area is the atmosphere. However, the atmospheric temperature fluctuates considerably depending on the environment, and further, when the engine oil chamber is heated, the heat penetrates through the connection body 1 and the base 3, and the contact oil in the airtight chamber 20 also enters a considerable amount. It gets hot.

When the temperature of the contact oil in the airtight chamber 20 fluctuates due to such factors, the volume of air contracts or expands accordingly. Then, the rubber cap 18 contracts or expands between the inner and outer caps 17 and 19 accordingly.

As a result, the pressure in the airtight chamber 20, that is, the pressure on the inner surface side of the diaphragm 5 is always maintained at about atmospheric pressure, and the diaphragm 5 is protected from the engine oil almost without being affected by the ambient temperature change. The oil pressure of the engine oil is constantly measured with constant displacement according to the change of oil pressure.

The present invention is not limited to the above embodiment, and for example, the rubber cap may be an inflatable / contractible elastic wall forming at least a part of the airtight wall forming the airtight chamber.

[0029]

[Effect of device]

 According to the oil pressure sensor of the present invention, the wear powder generated from the contact portion of the contact is made to flow and diffuse by the oil filled in the airtight chamber surrounding the contact portion and does not remain in the contact portion of the contact, so that it can be used for a long time. Even if there is no contact failure due to abrasion powder, the hydraulic pressure can be detected correctly.

Further, since the oil acts as a damper in the airtight chamber and the vibration resistance of the hydraulic pressure sensor itself is enhanced, excellent durability is obtained even when used in a device such as an automobile that is constantly vibrated. Have.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an example.

FIG. 2 is a partial perspective view of the embodiment.

FIG. 3 is a partially exploded perspective view of the embodiment.

[Explanation of symbols]

 2 Potentiometer (detection means) 5 Diaphragm 18 Rubber cap (elastic wall) 20 Airtight chamber 21 Resistance row 22 Brush 22a Electrical contact

Claims (1)

[Scope of utility model registration request] 1. To detect the displacement amount of the diaphragm caused by the change in the hydraulic pressure by arranging the inner surface side of the diaphragm receiving the hydraulic pressure on the outer surface so as to face the airtight chamber which is hermetically sealed to the outside. Further, in a hydraulic pressure sensor having a detecting means having a contact point that moves following the displacement of the diaphragm in the airtight chamber, at least a part of the airtight wall forming the airtight chamber is formed by an elastic wall that is expandable and contractible. At the same time, the oil pressure sensor is characterized in that the airtight chamber is filled with oil.