KR20150031995A

KR20150031995A - Pressure sensor apparatus

Info

Publication number: KR20150031995A
Application number: KR20130111939A
Authority: KR
Inventors: 김시동; 방현호; 강현준; 최정운
Original assignee: 주식회사 오토산업
Priority date: 2013-09-17
Filing date: 2013-09-17
Publication date: 2015-03-25

Abstract

The present invention is to provide a pressure sensing device with improved durability and reliability capable of reducing prime costs such as material costs and manufacturing expenses. According to the present invention, in order for the pressure sensing device to achieve this purpose includes: a pressure sensor where a plurality of wires transmitting sensing signals are connected; a circuit unit where the wires are welded; a connector including a terminal electrically connected to the circuit unit; and a housing having one end with an inlet where a medium is inserted, and the other end with a space unit where the pressure sensor is assembled. The present invention is characterized in that the circuit unit is fixated to the pressure sensor and composed of a hard circuit board wherein circuit components are mounted, and a flexible circuit board connected to the hard circuit board.

Description

Technical Field [0001] The present invention relates to a pressure sensor apparatus,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure sensor device, and more particularly, to a pressure sensor device for housing a pressure sensor in an internal space formed between a housing and a connector.

The pressure sensor is a sensor used to detect the pressure and convert it into electric signal. Its applications range from consumer electronics to large-scale system control of automobiles, medical devices, environment-related equipment and industries, There is a demand for a compact, lightweight, and low-cost pressure sensor that can be used in environments such as high humidity and high humidity.

The pressure sensor includes a pressure sensor for sensing the pressure, a connector for outputting the sensed signal to the outside, a circuit portion for amplifying the signal sensed by the pressure sensor and transmitting the sensed signal to the connector, Thereby forming a pressure sensor device.

U.S.A. Pat. No. 6,487,911 A type of pressure sensor device is disclosed in the pressure sensor apparatus. In the conventional pressure sensor device of the above-mentioned U.S. patent, the circuit part is made of only a flexible printed circuit board (FPCB). That is, the amplifying circuit is formed on the FPCB, and the component is mounted to amplify the signal. However, although FPCB is thin and lightweight, it has a higher manufacturing cost than a rigid printed circuit board (PCB) and tends to be torn. Therefore, the material cost rises and the FPCB is damaged in the course of handling the FPCB by the operator, and the FPCB with the circuit parts mounted thereon needs to be replaced. Further, the pressure sensor device is exposed and used under high vibration and physical impact environments. The contacts of the parts mounted on the FPCB are temporarily disconnected due to vibration and impact, which decreases the reliability of the product.

U.S.A. Pat. No. 6,487,911 Pressure sensor apparatus

The object of the present invention is to provide a pressure sensor device in which costs such as material cost and manufacturing cost are reduced, durability and reliability are improved.

According to an aspect of the present invention, there is provided a pressure sensor device including a pressure sensor to which a plurality of wires for sensing signals are connected, a circuit portion to which wires are connected, and a terminal to be electrically connected to the circuit portion And a housing having a connector, an inlet hole through which the medium flows into the one end, and a space in which the pressure sensor is assembled in fluid communication with the inlet hole at the other end, wherein the circuit portion is fixed to the pressure sensor, Lt; RTI ID = 0.0 > FPCB < / RTI >

According to the present invention, since the FPCB can be simplified, the material cost can be reduced, and the circuit parts can be mounted only on the PCB and not mounted on the FPCB. Therefore, even if the FPCB is broken during handling, , And the manufacturing cost can be reduced. In addition, since the circuit components are mounted on the PCB, the durability and reliability of the product can be improved, and the product can be easily repaired if the product is broken.

1 is a perspective view of a pressure sensor device according to an embodiment of the present invention;
2 is an exploded view of the pressure sensor device of Fig.
3 is a cross-sectional view of the pressure sensor device of Fig.
4 is a pattern diagram of a piezoelectric resistance type pressure sensor.

The present invention will now be described in detail with reference to the accompanying drawings. Here, the same reference numerals are used for the same components, and a detailed description of known functions and configurations that may unnecessarily obscure the gist of the present invention will be omitted. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. Accordingly, the shapes and sizes of the elements in the drawings and the like can be exaggerated for clarity.

FIG. 1 is a perspective view of a pressure sensor device 100 according to an embodiment of the present invention. FIG. 2 is an exploded view of the pressure sensor device 100 of FIG. 1, Fig.

1 to 3, a pressure sensor device 100 according to an embodiment of the present invention includes a pressure sensor 20, a circuit portion 10, a connector 40, and a housing 30.

The pressure sensor 20 may be any one of a capacitive type, a piezoelectric type, and a piezoresistive type. Among them, the piezoresistive type is strong against noise and can measure an accurate pressure, It is most preferable because it is less influenced by temperature, vibration and impact.

The piezoresistive type pressure sensor is formed by forming a pattern 22a made of an electrically conductive material and a plurality of strain gauges 22b on the surface of the diaphragm 22 to convert the pressure into a resistance change of the strain gauge 22b. Therefore, it is important to convert the pressure to a strain of the effective strain gauge 22b. When a uniform pressure is applied to the diaphragm 22 fixed on the outer circumferential surface, bending deformation occurs on the surface of the diaphragm 22, and microvibration generated on the back surface of the diaphragm 22 due to the applied pressure is caused by the whistle The Wheatstone bridge causes micro-resistance changes and converts them to electrical signals

4 shows the pattern 24 and the strain gauge 22b formed in the diaphragm 22 of the piezoresistive pressure sensor 20. As shown in Fig. It is confirmed that the electrode and the four strain gauges 22b are formed. It is preferable that the two resistors are located near the center where the deformation is greatest in the center direction of the circle of the diaphragm 22 and the other two are positioned in such a manner as to be placed over the edge having the greatest deformation in the circumferential direction of the circle of the diaphragm 22 . However, the shape and number of the pattern of the diaphragm 22 and the strain gauge are not limited, and therefore, it is possible to deform by the operator.

Meanwhile, the strain gauge 22b can be formed by depositing a CuNi or NiCr thin film by ion beam sputtering and patterning it by a photolithography process. It goes without saying that the patterning may be performed by any other known patterning method than the above patterning method. The resistance value of the strain gauge 22b can be adjusted between 100? And 1000? By varying the thickness of the thin film and the length of the gauge.

Since the material of the diaphragm 22 should electrically insulate the strain gauge 22b from the diaphragm 22, it is preferable to use ceramic.

A plurality of electrode holes 21a filled with a conductive material are formed in the substrate 21. [ The number of the electrode holes 21a may be the same as the number of the electrodes of the diaphragm 22. The conductive material filled in the electrode hole 21a of the base material 21 may be composed of one of silver, platinum, gold, aluminum, chromium and copper. have.

A wire 22 for transmitting a signal sensed by the pressure sensor 20 may be provided at the upper end of the electrode hole 21a and may be adhered to the circuit portion 11. [ The wire 22 can be soldered to the pad 11b formed in the circuit portion 11. [ The number of the wires 22 may be the same as the number of the electrode holes 21a.

It is preferable that the base material 21 and the diaphragm 22 are made of a rectangular flat plate. When the base material 21 and the diaphragm 22 are formed into a rectangular flat plate, the production is easy and the mass productivity is excellent, so that the production cost can be reduced.

Spacers (not shown) may be interposed between the substrate 21 and the diaphragm 22. The spacers serve to bond and separate the substrate 21 and the diaphragm 22. As the spacer, a low-melting glass or a glass frit can be used.

As shown in FIGS. 2 and 3, the circuit unit 10 includes a PCB 11 and an FPCB 13 connected thereto. The connection between the PCB 11 and the FPCB 13 can be achieved by soldering the FPCB 13 to the pad 11a formed on the PCB 11. [

The PCB 11 may be a ceramic substrate, a FR4 substrate, a BT substrate, or the like. The PCB 11 is fixed to the pressure sensor 20 by an adhesive or the like. A pattern of the amplifying circuit is formed on the PCB 11, and the circuit component 12 is mounted. The circuit component 12 may be an application specific integrated circuit (ASIC) that includes circuitry and the like to meet the objectives of the present invention. The PCB 11 on which the circuit component 12 is mounted receives a weak signal sensed by the pressure sensor 20 and amplifies the weak signal.

The FPCB 13 of the pressure sensor device 100 according to an embodiment of the present invention shown in FIGS. 2 and 3 is provided with three (3) corresponding to each terminal for electrically connecting to the terminal 41 of the connector 40 A terminal hole 13b is formed. A pad is formed on the outer circumferential surface of the terminal hole 13b and when the terminal 41 is inserted into the terminal hole 13b, a signal amplified by the PCB 11 is electrically connected to the connector 40 through the FPCB 13, Lt; / RTI > The FPCB 13 can be formed by forming a pattern such as a copper foil on the surface of the polyimide film.

The most significant feature of the pressure sensor device 100 according to the present invention is that the circuit portion 10 is separated from the PCB 11 and the FPCB 13. Since the circuit components 12 are mounted only on the PCB 11 and are not mounted on the FPCB 13, the FPCB 13 is more simple and easy to manufacture than the conventional products, and the material cost can be reduced. If the FPCB 13 is damaged in the handling process before assembling, the FPCB 13 can be replaced without the loss of the circuit component 12, thereby reducing manufacturing costs. In addition, since the product is mounted on the PCB 11, the product is relatively strong against vibration or shock, thereby improving the reliability of the product.

The circuit unit 10 may further include a grounding piece 13a extending from both sides of the FPCB 11 and electrically grounded as it contacts the housing 30. The grounding piece 13a is electrically connected to the housing 30 made of a metal and is grounded so that malfunction of the pressure sensor device 100 according to the present invention can be prevented by electromagnetic interference (EMI). A portion 40d of the connector 40a can be cut so that the grounding piece 13a can be connected to the housing 30a.

The connector 40 has a terminal 41 that is electrically connected to the circuit portion 10. The connector 40 can be manufactured by insert molding a synthetic resin material such as polybutylene terephthalate (PBT). According to the embodiment shown in Figs. 2 and 3, a coupling groove 40a is formed at one end of the connector 40, to which a mating member is coupled. The other end of the connector 40 is provided with a receiving groove 40b for receiving the pressure sensor 20 and the circuit unit 10, thereby fixing the pressure sensor. The three terminals 41 protruding into the coupling groove 40a and the receiving groove 40b are electrically connected to the circuit portion 10 at one end and to the pins of the mating connector at the other end to serve as input and output of electric signals.

An inlet hole 30c through which the measurement medium flows is provided at one end of the housing 30. And a space 30a in which the pressure sensor 20 and the connector 40 are assembled is formed at the other end in fluid communication with the inflow hole 30c. The pressure measuring medium such as an automobile refrigerant or the like that has entered the housing 30 through the inlet hole 30c applies pressure to the pressure sensor 20 assembled in the space portion 30a.

A thread 30d may be formed on the outer circumferential surface of the housing 30. The housing 30 is fastened to a mating member such as an air conditioner pipe nut or the like through the thread 30d. In the pressure sensor device 100 according to an embodiment of the present invention, the thread 30d is formed on the outer circumferential surface, but it may be formed on the inner circumferential surface.

After the connector 40 is assembled to the space 30a of the housing 30, the connector 40 is brought into close contact with the housing 30 to close the end of the housing 30 to seal the periphery of the pressure sensor 10 It can be constituted by bending. However, the present invention is not necessarily limited to this structure, and the interference fit structure of the housing 30 and the connector 40, the latching jaw structure, or the like may be used. The material of the housing 30 is preferably a metal such as aluminum for forming the screw thread or for bending.

The pressure sensor device 100 according to the present invention may further include O-rings 50 and 51. The O-rings 50 and 51 are provided to seal the periphery of the pressure sensor 20 and to prevent the entry of water, moisture, and the like. The O-rings 50 and 51 form a groove 30b for assembling the O-ring in the space 30a of the housing 30 And then inserted. In addition, by providing the O-ring 51 on the thread 30d, which is the connecting portion between the housing 30 and the mating member, it can be sealed more tightly.

First, a pressure measuring medium such as a refrigerant, which is drawn into the inlet hole 30c of the housing 30, is introduced into the diaphragm 20 of the pressure sensor 20, When a pressure is applied to the strain gauge 22, the resistance value of the strain gauge 22b is changed. The resistance value is converted into an electric signal and transmitted to the PCB 11 through the wire 21 connected to the pressure sensor 20. The electric signal transmitted to the PCB 11 is amplified by the electric circuit on the PCB 11 And is transmitted to an external electrical device such as an electronic control unit (ECU) through the FPCB 11 and the connector 40. [

The pressure sensor device 100 according to the present invention as described above can reduce the material cost and manufacturing cost since the circuit part 10 is formed by the PCB 11 and the FPCB 13, Since the product is mounted, the durability of the product is improved, so that it is possible to sense the pressure more accurately and it is easy to repair the product when the product is broken.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation and that those skilled in the art will recognize that various modifications and equivalent arrangements may be made therein. It will be possible. Accordingly, the true scope of protection of the present invention should be determined only by the appended claims.

100: pressure sensor device 10:
11: PCB 12: Circuit parts
13: FPCB 13a: Grounding piece
20: pressure sensor 21: substrate
22: diaphragm 30: housing
40: connector 41: terminal
50: O ring

Claims

A pressure sensor to which a plurality of wires for fetching a sensing signal are connected;
A circuit part to which the wire is bonded;
A connector having a terminal electrically connected to the circuit unit;
And a housing having an inlet hole through which the medium is introduced at one end and a space with which the pressure sensor is assembled in fluid communication with the inlet hole at the other end,
Wherein the circuit unit comprises a rigid circuit board fixed to the pressure sensor and having circuit components mounted thereon and a flexible circuit board connected to the rigid circuit board.

The method according to claim 1,
Wherein the pressure sensor is a piezoelectric resistance type sensor.

3. The method of claim 2,
The piezoelectric resistance type pressure sensor
A substrate on which a plurality of electrode holes filled with a conductive material are formed;
A diaphragm disposed opposite to the substrate and having a sensor pattern and a terminal formed on a surface facing the substrate;
A spacer interposed between the base material and the diaphragm to bond and separate the base material and the diaphragm, the spacer being formed along the outline of the base material and the diaphragm;
Pressure sensor device.

The method according to claim 1,
Wherein the FPCB includes a plurality of terminal holes electrically connected to the terminals as the terminals are inserted.

The method according to claim 1,
Wherein the pressure sensor device further comprises a waterproof O-ring for sealing.

The method according to claim 1,
Wherein the circuit unit further comprises a grounding piece extending from both sides of the FPCB and electrically grounded as it contacts the housing.