CN108375447A - Pressure sensor - Google Patents

Abstract

The present invention provides a pressure sensor in which there is no gap between the pressure detection element and the substrate to which external leads are connected even when the encapsulating resin expands due to heat, or when the encapsulating resin is cooled and shrinks. Thermal stress, the substrate will not be damaged, and pressure detection can be performed reliably. The pressure sensor includes: a joint member (14) forming a flow path (12); a pressure detection element (16) arranged to face the flow path of the joint member; and an external lead (54) connected to the pressure detection element. and an encapsulation resin portion (52) that fills the gap formed inside the cover member (42) and constitutes an adhesive, and the pressure detection element (16) is in contact with the substrate (38) connected to the external lead (54) status is configured.

Description

Pressure Sensor

This application is a divisional application; the application number of its parent application is "2013101988911", and the invention name is "pressure sensor".

technical field

The invention relates to a liquid-sealed pressure sensor.

Background technique

Conventionally, as a pressure sensor for detecting fluid pressure, Patent Document 1 (Japanese Patent Application Laid-Open No. 2012-68105) discloses a liquid-sealed pressure sensor 100 configured without a gap so that moisture does not enter from the outside.

As shown in FIG. 5 , this pressure sensor 100 is composed of a combination of a pressure detection element 102 , a joint member 104 , and a cover member 106 .

In addition, the outer peripheral edge portion of the metal diaphragm 108 is airtightly fastened to one end surface (lower bottom surface) of the pressure detection element 102 by welding. The wire bonding 112 is connected to the sensor chip 110 provided on the lower surface of the pressure detection element 102 through a lead pin 114 .

Furthermore, as shown in FIG. 5 , the lead pin 114 is connected to a substrate 116 and connected to an external lead 118 . Furthermore, an encapsulating resin 122 made of an adhesive is sealed in the space inside the cover member 106 , and an encapsulating resin 124 made of an adhesive is also sealed in the space between the cover member 106 and the joint member 104 . Therefore, there is no gap, and liquid such as moisture is prevented from entering the interior.

In addition, in the pressure sensor 100 of Patent Document 1, as shown in FIG. And the structure constituted by the small-diameter part 120c erected vertically from this step part 120b.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2012-68105

Contents of the invention

However, in the liquid-sealed pressure sensor 100 described in conventional Patent Document 1, as shown in FIG. 5 , a gap T is formed between the pressure detection element 102 and the substrate 116 at a constant interval.

Therefore, in the pressure sensor 100 of Patent Document 1, the encapsulation resin 122 enters between the pressure detection element 102 and the substrate 116, and when the encapsulation resin 122 expands due to heat, or when the encapsulation resin 122 is cooled and shrinks. Next, as shown by arrow A in FIG. 5 , thermal stress occurs.

Therefore, the substrate 116 may be damaged due to the thermal stress, and the pressure cannot be reliably detected.

Also, when the sealing resin 122 expands due to heat, or shrinks when the sealing resin 122 is cooled, thermal stress occurs between the pressure detection element 102 and the substrate 116 connected to the external lead 118 .

As a result, the connection portion 128 of the lead pin 114 connecting the pressure detection element 102 and the substrate 116 is damaged, and the electrical connection is cut off, and the connection portion 130 connecting the substrate 116 and the external lead 118 is sometimes damaged, and the electrical connection is cut off, making it impossible to perform. Accurate pressure detection.

In addition, as shown in FIG. 5 , since the pressure detection element 102 and the substrate 116 connected to the external lead 118 are separated, there is a gap T between the pressure detection element 102 and the substrate 116 connected to the external lead 118 . Therefore, a large amount of constituent adhesive encapsulation resin 122 is required, which increases the cost, and also increases the size of the pressure sensor itself.

In view of such circumstances, an object of the present invention is to provide a pressure sensor in which even when the encapsulating resin expands due to heat, or when the encapsulating resin is cooled and shrinks, the pressure sensor is connected to the external lead wire. There will be no thermal stress between the substrates, no damage to the substrates, and reliable pressure detection.

In addition, an object of the present invention is to provide a pressure sensor that does not cause problems in connecting a pressure detection element to a substrate when the encapsulating resin expands due to heat, or when the encapsulating resin contracts when cooled. When the connection portion of the lead pin is damaged and the electrical connection is cut off, or when the connection portion between the connection board and the external lead is damaged and the electrical connection is cut off, pressure detection can be reliably performed.

Another object of the present invention is to provide a pressure sensor in which the amount of a constituting adhesive encapsulating resin is reduced, the cost can be reduced, and the pressure sensor can be made compact and small.

The present invention is an invention made to achieve the above-mentioned problems and objects in the prior art. The pressure sensor of the present invention is characterized in that it includes: a joint member having a flow path formed therein; A pressure detection element that is fixed to the joint member and arranged to face the flow path of the joint member; an external lead connected to the pressure detection element; and a gap formed inside the cover member to fill and bond The sealing resin part of the agent is arranged in a state where the above-mentioned pressure detection element is in contact with the substrate to which the external leads are connected.

With this configuration, since the pressure detection element and the substrate to which the external leads are connected are arranged in contact with each other, there is no gap between the pressure detection element and the substrate to which the external leads are connected. Accordingly, when the sealing resin constituting the adhesive is injected, the sealing resin does not exist between the pressure detection element and the substrate to which the external leads are connected.

Therefore, when the encapsulating resin expands due to heat, or when the encapsulating resin is cooled and contracts, no thermal stress is generated between the pressure detection element and the substrate to which the external leads are connected, and the substrate is not damaged. Capable of reliable pressure detection.

In addition, since there is no thermal stress between the pressure detection element and the substrate connected to the external lead, the connection portion of the lead pin connecting the pressure detection element and the substrate will not be damaged and the electrical connection will not be cut off, or the connection between the substrate and the substrate will not be broken. When the connection part of the external lead wire is damaged and the electrical connection is cut off, pressure detection can be reliably performed.

Furthermore, since the pressure detection element and the substrate to which the external leads are connected are arranged in contact with each other, there is no gap between the pressure detection element and the substrate to which the external leads are connected. Therefore, the amount of the encapsulating resin constituting the adhesive is reduced, the cost can be reduced, and the pressure sensor can be made compact and small.

In addition, the pressure sensor of the present invention is characterized in that the cover member has a cylindrical shape including a portion that stands approximately vertically in a portion that houses the encapsulating resin portion.

With such a configuration, the cover member has a cylindrical shape with a portion that stands upright approximately vertically in the portion that accommodates the encapsulation resin. Therefore, there is no stepped portion extending on the inner diameter side as in the past, and the encapsulation resin portion of the cover member is open. status.

Therefore, even if the encapsulating resin expands due to heat, there will be no peeling between the encapsulating resin and the element body of the pressure detecting element due to thermal stress, and there will be no insulation failure or damage caused by moisture ingress from the outside. Pressure detection elements are affected by corrosion, etc., enabling accurate pressure detection.

In addition, the cover member has a cylindrical shape with a portion that is erected approximately vertically in the portion that accommodates the encapsulation resin portion. Therefore, there is a step portion and a small diameter portion that extend to the inner diameter side as in the past, and the encapsulation of the cover member The resin portion is in an open state.

Therefore, when injecting and encapsulating the resin, the injection operation is easy, no need to spend time and labor, and the cost can be reduced. Moreover, the resin spreads throughout the cover constituting the waterproof case, so that there will be no poor injection, bubbles, cracks, or cracks. Accurate pressure detection can be performed due to the effects of poor insulation caused by moisture entering from the outside, or corrosion of the pressure detection element.

The effects of the present invention are as follows.

According to the present invention, since the pressure detection element and the substrate to which the external leads are connected are arranged in contact with each other, there is no gap between the pressure detection element and the substrate to which the external leads are connected. Accordingly, when the sealing resin constituting the adhesive is injected, the sealing resin does not exist between the pressure detection element and the substrate to which the external leads are connected.

Therefore, when the encapsulating resin expands due to heat, or when the encapsulating resin is cooled and contracts, no thermal stress is generated between the pressure detection element and the substrate to which the external leads are connected, and the substrate is not damaged. Capable of reliable pressure detection.

In addition, since there is no thermal stress between the pressure detection element and the substrate connected to the external lead, the connection portion of the lead pin connecting the pressure detection element and the substrate will not be damaged and the electrical connection will not be cut off, or the connection between the substrate and the substrate will not be broken. When the connection part of the external lead wire is damaged and the electrical connection is cut off, pressure detection can be reliably performed.

Furthermore, since the pressure detection element and the substrate to which the external leads are connected are arranged in contact with each other, there is no gap between the pressure detection element and the substrate to which the external leads are connected. Therefore, the amount of the encapsulating resin constituting the adhesive is reduced, the cost can be reduced, and the pressure sensor can be made compact and small.

Description of drawings

Fig. 1 is a longitudinal sectional view of a pressure sensor of the present invention.

Fig. 2 is a longitudinal sectional view of another embodiment of the pressure sensor of the present invention.

Fig. 3 is a partially enlarged longitudinal sectional view of the pressure sensor of the present invention shown in Fig. 2 .

FIG. 4 is a graph showing stress analysis.

FIG. 5 is a longitudinal sectional view showing a conventional liquid-sealed pressure sensor 100 .

In the picture:

10—pressure sensor, 12—flow path, 14—joint part, 14a—flange, 16—pressure detection element, 18—element body, 18a—upper surface, 20—central opening, 22—sealing glass, 24—membrane Sheet, 26—communication hole, 28—membrane protective cover, 30—liquid seal chamber, 32—sensor sheet, 34—lead pin, 34a—front end, 36—metal wire, 38—substrate, 38a—through hole, 40— Pressure chamber, 42—cover member, 44—base end portion, 46—element body fitting portion, 48—encapsulation resin housing portion, 48a—encapsulation resin housing portion main body, 48b—step portion, 48c—small diameter portion, 50—opening Part, 52—encapsulation resin part, 54—external lead wire, 100—pressure sensor, 102—pressure detection element, 104—joint part, 106—cover part, 108—diaphragm, 110—sensor sheet, 112—wire bonding, 114 —Lead pin, 116—substrate, 118—external lead, 120a—cover body, 120b—step portion, 120c—small diameter portion, 122—encapsulation resin, 124—encapsulation resin, 126—element body, 128—connection portion, 130 - Connection part.

Detailed ways

Hereinafter, embodiments (examples) of the present invention will be described in more detail based on the drawings.

Example 1

Fig. 1 is a longitudinal sectional view of a pressure sensor of the present invention.

In FIG. 1, reference numeral 10 generally denotes a pressure sensor of the present invention.

As shown in FIG. 1 , the pressure sensor 10 of the present invention is a liquid-sealed pressure sensor, and includes a joint member 14 in which a flow path 12 is formed, and a pressure detection element 16 for detecting fluid pressure in the flow path 12 .

Furthermore, the pressure detection element 16 is disposed so as to face the flow path 12 of the joint member 14 , and is fastened to the joint member 14 by welding at its peripheral edge.

The pressure detecting element 16 includes an element body 18 made of metal such as stainless steel or aluminum, and a sealing glass 22 is fitted and fastened in a central opening 20 formed in the element body 18 .

In addition, as shown in FIG. 1 , the element body 18 of the pressure detecting element 16 , the metal diaphragm 24 , and the diaphragm protective cover 28 formed with the communication hole 26 are integrally welded at their peripheral edges.

Furthermore, with this structure, a liquid seal chamber 30 in which oil is sealed is formed between the sealing glass 22 and the diaphragm 24 at the portion of the central opening 20 of the element body 18 .

On the other hand, as shown in FIG. 1 , on the surface of the sealing glass 22 on the liquid-tight chamber 30 side, a sensor chip 32 having a monolithic structure is fixed with an adhesive.

The sensor chip 32 is arranged in the liquid-sealed chamber 30 and is configured as a pressure sensor chip in which a pressure element for detecting pressure and an integrated circuit for processing an output signal of the pressure detection element are integrated.

In addition, a plurality of lead pins 34 for inputting and outputting signals to the sensor chip 32 are respectively fixed to the sealing glass 22 by a sealing process in a penetrating state.

In this embodiment, although not shown, eight lead pins 34 are provided in total. That is, three lead pins 34 for external lead wires 62a (Vout), 62b (Vcc), and 62c (GND) described later as terminals for input and output, and five lead pins as terminals for adjusting the sensor chip 32 are provided. 34.

The lead pin 34 is conductively connected (wire bonding) to the sensor chip 32 by, for example, a metal wire 36 made of gold or aluminum, and constitutes an external output terminal and an external input terminal of the sensor chip 32 .

And, the fluid pressure transmitted from the flow path 12 of the joint member 14 to the pressure chamber 40 presses the surface of the diaphragm 24 through the communication hole 26 of the diaphragm protection cover 28, and is detected by the sensor sheet 32 in the liquid seal chamber 30. The bet pressure.

In addition, as shown in FIG. 1 , above the pressure detection element 16 , the pressure detection element 16 and the substrate 38 to which the external lead 54 is connected are arranged in a contact state. The front end 34a of the lead pin 34 is inserted through a through hole 38a formed at one end of the substrate 38, and is electrically connected to an unillustrated circuit of the substrate 38 by, for example, soldering.

On the other hand, at the other end of the substrate 38 , the external lead 54 is electrically connected to an unillustrated circuit of the substrate 38 by, for example, soldering.

In addition, as shown in FIG. 1 , the base end portion 44 of the cover member 42 is attached in a state of being in contact with the flange portion 14 a of the joint member 14 . The base end portion 44 of the cover member 42 and the flange portion 14 a of the joint member 14 are fastened by, for example, soldering, welding, an adhesive, or the like.

In addition, although the base end part 44 of the cover member 42 and the flange part 14a of the joint member 14 are fastened, they may be fitted and attached.

In this case, as shown in FIG. 1 , the cover member 42 is fitted with the base end portion 44 abutting against the flange portion 14 a of the joint member 14 and the element body fitted with the element body 18 of the pressure detection element 16 . The encapsulating resin part 46 and the encapsulating resin accommodating part 48 having a smaller diameter than the element body fitting part 46 and accommodating the encapsulating resin part 52 are integrally formed.

In addition, as shown in FIG. 1 , the encapsulation resin container 48 has a structure composed of an encapsulation resin container body 48a, a stepped portion 48b extending radially inward, and a small diameter portion 48c vertically erected from the stepped portion 48b.

In addition, as shown in FIG. 1 , the cover member 42 has a cylindrical shape having an opening 50 above the encapsulating resin container 48 .

As a result, as shown in FIG. 1 , a gap S is formed inside the sealing resin container 48 of the cover member 42 , and the sealing resin constituting the adhesive is filled into the gap S from the opening 50 side of the cover member 42 to form a space S. The resin part 52 is enclosed.

In the pressure sensor 10 of the present invention thus constituted, as shown in FIG. There is no gap between 38. Therefore, even when the sealing resin constituting the adhesive is injected, the sealing resin portion 52 does not exist between the pressure detection element 16 and the substrate 38 to which the external lead 54 is connected.

Therefore, when the encapsulating resin expands due to heat, or when the encapsulating resin is cooled and shrinks, thermal stress does not occur between the pressure detecting element 16 and the substrate to which the external lead 54 is connected, and the substrate 38 does not appear. breakage damage, enabling reliable pressure detection.

In addition, since no thermal stress is generated between the pressure detecting element 16 and the substrate 38 to which the external lead 54 is connected, the connection portion (the front end 34a of the lead foot 34) to the lead pin 34 connecting the pressure detecting element 16 to the substrate 38 does not occur. ) is damaged and the electrical connection is cut off, or the connection portion (54a) between the connection substrate 38 and the external lead 54 is damaged and the electrical connection is cut off, pressure detection can be reliably performed.

Example 2

2 is a longitudinal sectional view of another embodiment of the pressure sensor of the present invention, FIG. 3 is a partially enlarged longitudinal sectional view of the pressure sensor of the present invention shown in FIG. 2 , and FIG. 4 is a diagram showing stress analysis.

The pressure sensor 10 of this embodiment basically has the same configuration as the pressure sensor 10 shown in FIGS. 1 to 2 , and the same components are assigned the same reference numerals, and detailed description thereof will be omitted.

Like the pressure sensor 10 of the first embodiment shown in FIG. 1 , the pressure detection element 16 is arranged in contact with the substrate 38 to which the external lead 54 is connected.

Furthermore, as shown in FIG. 2 , the cover member 42 has a cylindrical shape in which the encapsulating resin container 48 constitutes a substantially vertically erected portion and has an opening 50 thereon.

In this case, the shape of the cover member 42 means "substantially vertical" in the meaning of a portion that is erected approximately vertically in the encapsulating resin container 48 that houses the encapsulating resin portion 52, as As shown in FIG. 3, for example, the angle α formed by the upper surface 18a of the element main body 18 of the pressure detection element 16 and the encapsulation resin containing portion 48 is about 90°, preferably in the range of 90°±1°, and the latter can be realized. the effect described.

In the pressure sensor 10 of the present invention thus constituted, as shown in FIG. Since the substantially vertically erected portion has a cylindrical shape, there is no stepped portion extended on the inner diameter side as in the conventional art, and the encapsulating resin portion 52 of the cover member 42 is in an open state.

Therefore, even when the encapsulating resin expands due to heat, or the encapsulating resin is cooled and contracts, as shown in FIG. The part A) surrounded by the ellipse in Fig. 3 will not peel off due to thermal stress, will not cause insulation failure due to moisture entering from the outside, or will not cause corrosion to the pressure detection element, and can perform accurate pressure detection.

In addition, as shown in FIG. 2, the cover member 42 is a cylindrical shape provided with a portion erected approximately vertically in the encapsulation resin container 48 as a portion for accommodating the encapsulation resin portion 52, so there is no such thing as a conventional extending portion. The stepped portion on the inner diameter side, the small diameter portion, and the encapsulating resin portion 52 enclosed in the gap S inside the encapsulating resin container 48 of the cover member 42 are opened by the opening 50 of the cover member 42 .

Therefore, when injecting and encapsulating the resin, the injection operation is easy, no need to spend time and labor, and the cost can be reduced, and the resin spreads throughout the cover member 42 constituting the waterproof case, so that poor injection, air bubbles, and cracks will not occur. Accurate pressure detection can be performed without causing insulation failure or corrosion of the pressure detection element 16 due to moisture entering from the outside.

FIG. 4 is a graph showing stress analysis when changing from 100°C to -40°C. As shown in FIG. 4(A), as in the pressure sensor 100 of Patent Document 1, if The shape is composed of a cover main body portion 120a as a large diameter portion, a stepped portion 120b extended on the inner diameter side, and a small diameter portion 120c vertically erected from the stepped portion 120b, and the sealing resin 122 and the pressure detection element Between the main body 126 of the element 102, the stress value is as large as 21 MPa.

On the other hand, as shown in FIG. 4(B), like the pressure sensor 10 of the present invention, the shape of the cover member 42 constituting the waterproof case is approximately In the case where the vertically erected portion has a cylindrical shape including the approximately vertically erected portion, it can be seen that the stress value can be reduced to one-third of 6 MPa.

As mentioned above, the preferred embodiment of the present invention has been described, but the present invention is not limited thereto. , the element body fitting portion 46 that fits into the element body 18 of the pressure detecting element 16, and the encapsulation resin housing portion 48 that accommodates the encapsulation resin portion 52 with a diameter slightly smaller than the element body embedding portion 46 are integrally formed. Various changes can be made in the range which does not deviate from the object of this invention, such as a cover member which consists of separate parts and is mutually fastened.

Industrial availability

The present invention can be applied to liquid-sealed pressure sensors.

Claims (7)

1. A pressure sensor, characterized in that, have: A joint part forming a flow path; A pressure detection element that is fastened to the joint member to detect the pressure of the fluid in the flow channel, and arranged to face the flow channel of the joint member; External leads connected to the above pressure sensing element; and The encapsulation resin portion that fills the gap formed inside the cover member and constitutes the adhesive, The above-mentioned pressure detection element is a structure sealed with oil, The above-mentioned pressure detection element is arranged in a state of being in contact with the substrate to which the external leads are connected. 2. The pressure sensor according to claim 1, characterized in that, The pressure sensor described above is a liquid-sealed pressure sensor. 3. The pressure sensor according to claim 2, characterized in that, The metal element main body of the above-mentioned pressure detection element is integrally fastened with a metal diaphragm at its outer peripheral edge portion by welding. 4. The pressure sensor according to claim 3, characterized in that, The pressure detection element is welded and fastened to the joint member at its peripheral portion. 5. A pressure sensor, characterized in that, have: A joint part forming a flow path; A pressure detection element that is fastened to the joint member to detect the pressure of the fluid in the flow channel, and arranged to face the flow channel of the joint member; External leads connected to the above pressure sensing element; and The encapsulation resin portion that fills the gap formed inside the cover member and constitutes the adhesive, The above-mentioned pressure detection element has a metal element body, The element body and the metal diaphragm are integrally fastened by welding, A liquid seal chamber filled with oil is formed between the element body and the diaphragm, The above-mentioned pressure detection element is arranged in a state of being in contact with the substrate to which the external leads are connected. 6. A pressure sensor, characterized in that, have: A joint part forming a flow path; A pressure detection element that is fastened to the joint member to detect the pressure of the fluid in the flow channel, and arranged to face the flow channel of the joint member; External leads connected to the above pressure sensing element; and The encapsulation resin portion that fills the gap formed inside the cover member and constitutes the adhesive, The above-mentioned pressure detection element has a metal element body, and sealing glass is embedded and fastened in the element body, The element body and the metal diaphragm are integrally fastened by welding, A liquid seal chamber filled with oil is formed between the sealing glass and the diaphragm inside the element body, The above-mentioned pressure detection element is arranged in a state of being in contact with the substrate to which the external leads are connected. 7. The pressure sensor according to claim 6, characterized in that, The pressure detection element has a metal element body, and a sealing glass is fitted into a central opening formed in the element body and fastened. A liquid seal chamber in which oil is sealed is formed between the sealing glass and the diaphragm at the central opening of the element body.