KR101741679B1 - Pressure sensor for fuel tank - Google Patents

Abstract

The pressure sensor for a fuel tank according to the present invention comprises a main body portion having a seating groove formed therein and an insertion portion extending downward from a position corresponding to the seating groove in a bottom surface of the main body portion and having a pressure- An outer housing; A chip housing which is formed to have an inner space opened on an upper side and is seated in the seating groove and has an opening hole communicating with the pressure guide opening on a bottom surface thereof; A sensor chip mounted on an inner space of the chip housing to cover an upper surface of the opening hole; And the gel is formed so as to fill the opening hole, wherein the opening hole is formed so that all or a part of the inner wall is inclined in a direction in which the cross-sectional area increases toward the lower side. The pressure sensor for a fuel tank according to the present invention is capable of reliably detecting the pressure inside the pressure tank by preventing inflow of foreign matter into the pressure inlet and increasing the gel expansion pressure due to the pressure change inside the pressure tank , The internal structure is simplified, and manufacturing cost is reduced and miniaturization is possible.

Description

Pressure sensor for fuel tank {PRESSURE SENSOR FOR FUEL TANK}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a pressure sensor for a fuel tank for measuring a pressure in a fuel tank, and more particularly to a pressure sensor for preventing the inflow of foreign matter into a pressure inlet, To a pressure sensor for use.

BACKGROUND ART An automobile has a fuel tank that receives power for driving by burning fuel and air in the engine, and stores fuel for supplying the engine to the engine.

The fuel tank is also provided with a pressure sensor for diagnosing the leakage of the evaporative gas system by the negative pressure diagnosis described later. In addition, the evaporated gas generated in the fuel tank flows into the canister and is collected. The evaporated gas collected in the canister is controlled through the purge control valve, is introduced into the surge tank, and mixed uniformly with the intake air, Burned in the combustion chamber.

At this time, the engine electronic controller is subjected to a step of checking whether or not the evaporation gas system is leaking. The method of examining the leak in the gasoline vehicle may be classified into a pressurized diagnosis system and a negative pressure system in which the pressure sensor is installed in the fuel tank. There is a negative pressure type diagnosis method in which a negative pressure is formed in the fuel tank using a pressure sensor and the pressure fluctuation is measured.

In the case of the negative pressure diagnosis system, the engine electronic controller closes the canister closing valve in the engine idling state to shut off the whole of the evaporation gas system from the external atmospheric pressure, and then operates the purge control valve to make the inside of the fuel tank into a vacuum state, The purge control valve is closed and the pressure change inside the fuel tank is checked for a predetermined time. The engine electronic controller calculates the pressure change to determine whether or not the evaporation gas system leaks. At this time, the pressure sensor for the fuel tank detects the pressure change.

A conventional pressure sensor for a fuel tank is provided with a sensor chip which receives pressure through an inlet of a pressure conduit communicating with the inside of the fuel tank and senses a pressure magnitude in the fuel tank, a PCB where the sensor chip is mounted, And a lead pin electrically connected to the PCB as a basic component. The conventional pressure sensor for a fuel tank configured as above has an advantage that the pressure inside the fuel tank can be measured even when the sensor chip for sensing the pressure is located outside the fuel tank. However, in the conventional pressure sensor for a fuel tank, there is a possibility that a foreign matter may be introduced through the space between the sensor chip and the pressure introducing port, and when the pressure change in the pressure tank is not large, In addition, since the lead pin and the sensor chip are electrically connected by the PCB, the internal structure is complicated and it is difficult to downsize the chip.

KR 10-2013-0138424 A

SUMMARY OF THE INVENTION The present invention has been proposed in order to solve the problems described above, and it is an object of the present invention to provide an apparatus and a method for preventing inflow of foreign matter into the pressure inlet, And to provide a pressure sensor for a fuel tank capable of reducing the size and size of the fuel tank.

According to another aspect of the present invention, there is provided a pressure sensor for a fuel tank, comprising: a main body having a seating groove formed therein; a downwardly extending portion extending downward from a position corresponding to the seating groove in a bottom surface of the main body, An outer housing including an insertion portion formed with a pressure introduction port; A chip housing which is formed to have an inner space opened on an upper side and is seated in the seating groove and has an opening hole communicating with the pressure guide opening on a bottom surface thereof; A sensor chip mounted on an inner space of the chip housing to cover an upper surface of the opening hole; And the gel is formed so as to fill the opening hole, wherein the opening hole is formed so that all or a part of the inner wall is inclined in a direction in which the cross-sectional area increases toward the lower side.

The lower end of the opening hole is formed to have a larger cross-sectional area than the upper end of the pressure introducing port so that the bottom surface of the gel filled in the opening hole covers the pressure inlet upper inlet and the pressure inlet upper inlet.

The upper portion of the inner wall of the opening hole is formed obliquely and the lower portion is vertically erected.

The chip housing further includes a protruding end protruding downward from the bottom surface, and the opening hole is formed to penetrate the protruding end in a vertical direction.

A lead pin having one end penetrated through the side wall of the chip housing and wire bonding for connecting one end of the lead pin to the sensor chip.

The lead pin includes a main lead having one end passing through a side wall of the chip housing and positioned in an inner space of the chip housing and an extension lead extending from an end of the main lead and thinner in width and thickness than the main lead ,

The wire bonding is configured to connect the extension lead and the sensor chip.

The extension lead extends horizontally from an end of the main lead and has an end bent upward, and the wire bonding is configured to connect the end of the extension lead and the sensor chip.

A covering layer filled in the inner space of the chip housing to cover the sensor chip, and a cover covering the top of the seating groove.

The pressure sensor for a fuel tank according to the present invention prevents inflow of foreign substances into the pressure inlet and adjusts the gel expansion pressure due to the pressure change inside the pressure tank to more reliably detect the pressure inside the pressure tank , The internal structure is simplified, and manufacturing cost is reduced and miniaturization is possible.

1 is a vertical sectional view of a pressure sensor for a fuel tank according to the present invention.
2 is a vertical sectional view of a chip package included in a pressure sensor for a fuel tank according to the present invention.
3 and 4 are a vertical cross-sectional view and a plan view of a second embodiment of a chip package included in a pressure sensor for a fuel tank according to the present invention.

Hereinafter, an embodiment of a pressure sensor for a fuel tank according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a vertical sectional view of a pressure sensor for a fuel tank according to the present invention, and FIG. 2 is a vertical sectional view of a chip package included in a pressure sensor for a fuel tank according to the present invention.

The pressure sensor for a fuel tank according to the present invention is an apparatus for measuring a pressure in a fuel tank which rises as fuel evaporative gas is generated in a fuel tank. The pressure sensor includes a body 110 having a seating groove 112, And an insertion portion 120 formed with a pressure-receiving opening 122 formed in a through-hole shape and an inner space opened on the upper side and seated in the seating groove 112, A chip housing 200 in which an opening hole 220 communicating with the pressure introducing port 122 is formed and a sensor chip 300 which is seated in the inner space of the chip housing 200 so as to cover the upper surface of the opening hole 220 And a gel 230 which is provided to fill the opening hole 220 as a basic component.

The insertion portion 120 extends downward from a position corresponding to the seating groove 112 in the bottom surface of the main body 110 so that the upper inlet of the pressure receiving opening 122 communicates with the seating groove 112, The gel 230 filled in the opening hole 220 of the chip housing 200 is configured to cover the upper inlet of the pressure introducing port 122. The lower end of the sensor chip 300 is attached to the bottom surface of the seating groove 112 by a separate adhesive P. In FIG. 1, in order to more clearly display the adhesive P, 122 are shown spaced from the top inlet, but substantially the gel 230 is configured to completely seal the top inlet of the pressure inlet 122. In addition, an O-ring is provided on the outer surface of the inserting portion 120 so that the fuel evaporation gas inside the fuel tank does not flow out to the outside. The O-ring is applied to the pressure sensor for the conventional fuel tank substantially similarly , The mounting position and function of the O-ring will not be described in detail.

At this time, the gel 230 having a certain level of fluidity so that pressure can be transferred into the opening hole 220 so that the fuel evaporation gas flowing through the pressure-introducing port 122 is not directly contacted to the sensor chip 300, The pressure sensor for a fuel tank according to the present invention is characterized in that the opening hole 220 to be filled with the gel 230 is not formed in a cylindrical shape but a part of the inner wall is formed to be inclined.

That is, as shown in FIG. 2, the opening hole 220 is formed such that a part of the inner wall is inclined in a direction in which the cross-sectional area increases toward the lower side. When the inner wall of the opening hole 220 is inclined, the bottom surface area of the gel 230 becomes wider and the bottom surface of the gel 230 filled in the opening hole 220 is positioned above the pressure inlet 122 Not only the inlet but also the pressure is covered to the vicinity of the upper inlet of the inlet 122 so that the upper inlet of the pressure inlet 122 is more stably sealed. Therefore, the foreign matter is prevented from entering the inside of the pressure intakes 122 and the pressure inside the pressure intakes 122 is applied to the gel 230, so that the sensor chip 300 can accurately measure the internal pressure of the fuel tank It is possible to obtain an effect that measurement can be performed.

When pressure is applied to the bottom surface of the gel 230 contacting the pressure intakes 122, the gel 230 is inflated to pressurize the sensor chip 300 so that the pressure applied to the sensor chip 300 When the gel 230 is filled with the opening 230, the opening 230 is filled with the gel 230 when the pressure is applied to the bottom surface of the gel 230. As a result, So that the sensing sensitivity of the sensor chip 300 is greatly increased.

In other words, when the upper cross-sectional area of the gel 230 is narrower than the lower cross-sectional area of the gel 230, the height of the sensor 230, which is expanded to the opposite side with respect to the applied pressure, Has the advantage of being able to accurately detect very small pressure changes.

In this embodiment, only a part of the inner wall of the opening hole 220 is formed to be inclined. However, the entire inner wall of the opening hole 220 may be inclined. However, if the entire inner wall of the opening hole 220 is formed to be inclined, the bottom surface area of the chip housing 200 is narrowed correspondingly, so that the bonding force of the chip housing 200 coupled to the bottom surface of the seating groove 112 may be reduced. , It is preferable that only a part of the inner wall of the opening hole 220 is formed to be inclined as shown in this embodiment.

When the entire inner wall of the opening hole 220 is formed to be inclined, a frictional stress is generated between the inner wall of the opening hole 220 and the gel 230 as soon as pressure is applied to the bottom surface of the gel 230, The magnitude of the pressure applied to the pressure chamber 300 may be somewhat reduced. Therefore, the pressure sensor for a fuel tank according to the present invention is characterized in that the pressure applied through the pressure-introducing port 122 at the initial stage of pressing the bottom surface of the gel 230 causes friction stress between the inner wall of the opening hole 220 and the gel 230 The upper portion of the inner wall of the opening hole 220 may be inclined and the lower portion may be vertically erected.

When the pressure applied through the pressure intakes 122 is applied to the bottom surface of the gel 230, the gel 230 flows through the vertically erected inner wall at a time when the inner wall of the opening 230 is inclined, The pressure drop applied to the sensor chip 300 can be reduced to a certain level.

The inclination of the inner wall of the opening hole 220 should be appropriately selected according to various conditions such as the magnitude of the pressure applied through the pressure inlet 122, the expansion coefficient of the gel 230, and the sensitivity of the sensor chip 300 .

When the bottom plate of the chip housing 200 is formed in a flat plate shape in which the opening hole 220 of the chip housing 200 is formed, the length of the opening hole 220 is shortened, The capacity of the gel 230 filled in the container 200 also decreases. As the gel 230 capacity decreases, the gel 230 may be detached from the opening hole 220 and the fuel evaporation gas may directly contact the sensor chip 300. Therefore, It is preferable that the portion where the middle opening hole 220 is formed is made to have a thickness of a predetermined level or more. That is, the chip housing 200 further includes a protruding end 210 protruding downward from the bottom surface, and the opening hole 220 is formed to penetrate the protruding end 210 in a vertical direction. When the opening 220 is formed in the protruding end 210 extending downward as described above, there is an effect that the capacity of the gel 230 is increased and the possibility that the gel 230 is removed from the opening hole 220 is reduced .

In order to prevent the sensor chip 300 from being oxidized and damaged, a cover layer 240 is disposed in the inner space of the chip housing 200 so as to cover the sensor chip 300, and a chip package The upper part of the seating groove 112 may be covered by a separate cover 700 so that the sensor chip 300 can be protected as a whole. The cover 700 may be fixed to the upper surface of the outer housing 100 by an adhesive P applied to the lower end of the cover 700 as shown in the present embodiment or may be detachably attached to the outer housing 100 0.0 > 100). ≪ / RTI >

3 and 4 are a vertical cross-sectional view and a plan view of a second embodiment of a chip package included in a pressure sensor for a fuel tank according to the present invention.

The pressure sensor for the fuel tank has a lead pin 500 through which one end of the pressure sensor penetrates the side wall of the chip housing 200 and is drawn into the inner space of the chip housing 200 for electrical signal transmission / Essentially required.

The sensor chip 300 is electrically connected to a separate PCB 400 as shown in FIGS. 1 and 2. The lead pin 500 is electrically connected to the PCB 400 by wire bonding 600, . However, if the PCB 400 for electrically connecting the lead pin 500 and the sensor chip 300 is provided as described above, the chip housing 200 must be made large so that the PCB 400 can be seated. There is a disadvantage in that the overall size of the pressure sensor for the fuel tank is increased, that is, the miniaturization of the product is limited.

Therefore, the pressure sensor for a fuel tank according to the present invention can be configured so that the lead pin 500 is directly connected to the sensor chip 300. When the lead pin 500 is directly connected to the sensor chip 300 as described above, since the PCB 400 for electrically connecting the lead pin 500 to the sensor chip 300 is not needed, It is possible to reduce the size of the chip housing 200 by the size of the space that is used and thus to miniaturize the overall size of the pressure sensor for the fuel tank. In addition, since the PCB 400 is omitted, the internal structure is simplified and the manufacturing process is simplified. Thus, the manufacturing cost of the pressure sensor for a fuel tank according to the present invention can be reduced and productivity can be increased.

3 and 4, when the lead pin 500 is too thick, the reliability of the bonding of the wire bonding 600 may be deteriorated. Therefore, the lead pin 500 may have one end connected to the chip housing 200 A main lead 510 extending from an end of the main lead 510 and having a width and a thickness thinner than the main lead 510, the main lead 510 being positioned in an inner space of the chip housing 200 through a side wall of the chip housing 200, And the wire bonding 600 may be bonded to the sensor chip 300 to connect the extension lead 520 to the sensor chip 300. In addition, when the portion to which the wire bonding 600 is bonded is made as thin as the extended lead 520, a thermal passivation effect can be obtained.

If the extended leads 520 are formed to extend in the horizontal direction, it is difficult to bond the wire bonding 600 to the ends of the extended leads 520. The extended leads 520 are connected to the main leads 510 And may be bent such that its end is directed upward. When the end of the extended lead 520 is bent so that the end of the extended lead 520 is directed upwardly, the operation of bonding the wire bonding 600 to the end of the extended lead 520 is remarkably facilitated and the reliability of bonding is improved Can be expected.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the present invention is not limited to the disclosed exemplary embodiments. It will also be appreciated that many modifications and variations will be apparent to those skilled in the art without departing from the scope of the invention.

P: adhesive 100: outer housing
110: main body part 112: seat groove
120: insertion part 122: pressure guide inlet
200: chip housing 210: protruding end
220: aperture hole 230: gel
240: Coat layer 300: Sensor chip
400: 500 F: Lead pin
510: main lead 520: extension lead
600: wire bonding 700: cover

Claims (8)

A pressure introducing port 122 extending downward from a position corresponding to the seating groove 112 in the bottom surface of the main body 110 and having a vertical through hole shape, An outer housing 100 having an insertion portion 120 formed therein;
A chip housing (200) formed to have an opened upper side and seated in the seating groove (112) and having an opening hole (220) communicating with the pressure guide opening (122) on the bottom surface thereof;
A sensor chip 300 mounted on the inner space of the chip housing 200 to cover an upper surface of the opening hole 220;
A gel 230 provided to fill the opening hole 220;
A lead pin 500 having one end inserted through the side wall of the chip housing 200; And
And a wire bonding (600) connecting one end of the lead pin (500) to the sensor chip (300)
The opening hole 220 is formed so that all or a part of the inner wall is inclined in a direction in which the sectional area increases toward the lower side,
The lead pin 500 includes a main lead 510 having one end passing through a side wall of the chip housing 200 and positioned in an inner space of the chip housing 200, And an extension lead 520 having a smaller width and a thickness than the main lead 510,
The wire bonding 600 is configured to connect the extension lead 520 and the sensor chip 300,
The extension lead 520 extends horizontally from the end of the main lead 510 and has an end bent upward,
Wherein the wire bonding (600) is configured to connect the end of the extension lead (520) to the sensor chip (300). The method according to claim 1,
The lower end of the opening hole 220 is formed to have a larger sectional area than the upper end of the pressure introducing port 122. The bottom surface of the gel 230 filled in the opening hole 220 is connected to the upper inlet of the pressure introducing port 122, (122) to the vicinity of the upper inlet of the inlet (122). The method of claim 2,
Wherein an upper portion of the inner wall of the opening hole (220) is formed obliquely and a lower portion is vertically erected. The method according to claim 1,
The chip housing (200) further includes a protruding end (210) protruding downward from the bottom surface, and the opening hole (220) is formed to penetrate the protruding end (210) vertically. Pressure sensor. delete delete delete The method according to claim 1,
A cover layer (240) filled in the inner space of the chip housing (200) to cover the sensor chip (300), and a cover (700) covering the top of the seating groove (112) Pressure sensor for use.

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