JP2014016333A - Pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensor capable of accurately detecting pressure, without causing peeling caused by heat stress to occur between a sealing resin and an element body of a pressure detection element in both cases where the sealing resin is expanded by heat and is shrunk by cooling, and thereby causing no insulation failure or affecting the pressure detection element with no corrosion or the like due to the infiltration of moisture from the outside.SOLUTION: A pressure sensor comprises: a joint member 14 formed with a flow channel 12; a pressure detection element 16 arranged to face the flow channel 12 of the joint member 14; an outer lead wire 54 connected to the pressure detection element; and a sealing resin part 52 being filled in a gap formed inside a cover member 42 and constituting an adhesive. The cover member 42 has a cylindrical shape including a substantially vertically-erected portion in a sealing resin housing part 48 for housing the sealing resin part.

Description

  The present invention relates to a liquid ring type pressure sensor.

  Conventionally, as a pressure sensor for detecting fluid pressure, Patent Document 1 (Japanese Patent Laid-Open No. 2012-68105) discloses a liquid-sealed pressure sensor 100 configured to have no gap so that moisture does not enter from the outside. Has been.

  As shown in FIG. 6, the pressure sensor 100 includes a combined body of a pressure detection element 102, a joint member 104, and a cover member 106.

  The outer peripheral edge of the metal diaphragm 108 is airtightly fixed to one end face (lower bottom face) of the pressure detection element 102 by welding. A lead pin 114 is connected to a sensor chip 110 provided on the lower surface of the pressure detection element 102 via a wire bonding 112.

  Further, as shown in FIG. 6, the lead pin 114 is connected to the substrate 116 and is connected to the external lead wire 118. An encapsulating resin 122 made of an adhesive is enclosed in the space in the cover member 106, and an encapsulating resin 124 made of an adhesive is also enclosed in the space between the cover member 106 and the joint member 104. ing. As a result, there is no gap and liquid such as moisture is prevented from entering the inside.

JP 2012-68105 A

  However, in the liquid-sealed pressure sensor 100 as described in Patent Document 1 as described above, as shown in FIG. 6, the shape of the cover member 106 constituting the waterproof case has a large diameter portion. The cover main body portion 120a, a step portion 120b extending to the inner diameter side, and a small diameter portion 120c erected vertically from the step portion 120b.

  For this reason, in the pressure sensor 100 of Patent Document 1, when the encapsulating resin 122 expands due to heat, there is a stepped portion 120b extending on the inner diameter side, so that as shown by the arrow B in FIG. Thermal stress is generated.

  As a result, due to the thermal stress, peeling occurs between the portion C enclosed by the ellipse in FIG. 6, that is, the encapsulating resin 124, the encapsulating resin 122, and the element body 126 of the pressure detecting element 102. As indicated by the arrow D, moisture enters from the outside through the peeled portion, affecting insulation and corroding the pressure detecting element 102, and accurate pressure detection cannot be performed.

  Further, as shown in FIG. 6, the cover member 106 includes a cover main body portion 120a having a large diameter portion, a step portion 120b extending to the inner diameter side, and a small diameter standing vertically from the step portion 120b. Therefore, when the encapsulating resin 122 is put, it is injected through the small diameter portion 120c. As a result, the injection work becomes complicated, time-consuming, and expensive. .

  Furthermore, when the encapsulating resin 122 is put, it is injected through the small diameter portion 120c, so that the resin does not spread over the entire cover main body portion 120a, which is the large diameter portion, resulting in poor injection, bubbles, and cracks. As a result, moisture enters from the outside and influences insulation failure and corrosion on the pressure detection element 102, so that accurate pressure detection cannot be performed.

  In view of the current situation, the present invention, even when the encapsulating resin expands due to heat, or when the encapsulating resin is cooled and contracts, between the encapsulating resin and the element body of the pressure detection element, To provide a pressure sensor that does not cause peeling due to thermal stress, and that can accurately detect pressure without moisture entering from the outside and without affecting insulation and corrosion on the pressure detection element. Objective.

  In addition, the present invention is easy when filling the encapsulating resin, does not take time and effort, can reduce the cost, the resin spreads over the entire cover constituting the waterproof case, poor injection, A pressure sensor that can detect pressure accurately without causing bubbles and cracking, and moisture entering from the outside, without affecting insulation or corroding the pressure detection element. The purpose is to provide.

The present invention has been invented in order to achieve the problems and objects in the prior art as described above.
A joint member in which a flow path is formed;
In order to detect the pressure of the fluid in the flow path, a pressure detection element fixed to the joint member and disposed so as to face the flow path of the joint member;
An external lead connected to the pressure sensing element;
An encapsulating resin portion that fills a gap formed inside the cover member and constitutes an adhesive;
With
The cover member has a cylindrical shape including a portion that is erected substantially vertically in a portion that accommodates the encapsulating resin portion.

  By configuring in this way, the cover member has a cylindrical shape with a portion that is erected substantially vertically in the portion that accommodates the encapsulating resin portion, and thus is extended to the inner diameter side as in the past. There is no step portion, and the encapsulating resin portion of the cover member is open.

  Therefore, even when the encapsulating resin expands due to heat, or when the encapsulating resin cools and contracts, no peeling occurs due to thermal stress between the encapsulating resin and the element body of the pressure detection element. Detects accurate pressure without intrusion of moisture from the outside and influence of insulation failure or corrosion on the pressure detection element.

  In addition, since the cover member has a cylindrical shape with a portion that is erected substantially vertically in the portion that accommodates the encapsulating resin portion, the stepped portion and the small-diameter portion that are extended to the inner diameter side as in the past are provided. It does not exist, and the encapsulating resin portion of the cover member is in an open state.

  Therefore, when filling the encapsulated resin, the injection work is easy, hassle-free, can reduce costs, and the resin spreads over the entire cover constituting the waterproof case, resulting in poor injection and bubbles. As a result, moisture can penetrate from the outside without causing cracks, and it is possible to detect pressure accurately without causing an influence of insulation failure or corrosion on the pressure detection element.

  The pressure sensor according to the present invention is characterized in that the pressure detection element and a substrate to which an external lead wire is connected are arranged in contact with each other.

  With this configuration, the pressure detection element and the substrate to which the external lead wire is connected are arranged in contact with each other, so that the pressure detection element and the substrate to which the external lead wire is connected are arranged. There is no gap. For this reason, even when the encapsulating resin constituting the adhesive is injected, there is no encapsulating resin between the pressure detection element and the substrate to which the external lead wire is connected.

  Therefore, even when the encapsulating resin expands due to heat or when the encapsulating resin cools and contracts, no thermal stress is generated between the pressure detection element and the substrate to which the external lead wire is connected. The pressure detection element can be reliably detected without being damaged and damaged.

  In addition, since no thermal stress is generated between the pressure detection element and the board to which the external lead wire is connected, the connection between the pressure detection element and the lead pin that connects the board is damaged and the electrical connection is interrupted. The connecting portion connecting the substrate and the external lead wire is not damaged and the electrical connection is not cut off, and the pressure can be reliably detected.

  Further, since the pressure detection element and the substrate connecting the external lead wire are arranged in contact with each other, there is no gap between the pressure detection element and the substrate connecting the external lead wire. For this reason, the amount of encapsulating resin constituting the adhesive can be reduced, the cost can be reduced, and the pressure sensor can be made compact and small.

  According to the present invention, since the cover member has a cylindrical shape having a portion that is erected substantially vertically in the portion that accommodates the encapsulating resin portion, the step portion that is extended to the inner diameter side as in the prior art. Is not present, and the encapsulating resin portion of the cover member is open.

  Therefore, even when the encapsulating resin expands due to heat, or when the encapsulating resin cools and contracts, no peeling occurs due to thermal stress between the encapsulating resin and the element body of the pressure detection element. Detects accurate pressure without intrusion of moisture from the outside and influence of insulation failure or corrosion on the pressure detection element.

  In addition, since the cover member has a cylindrical shape with a portion that is erected substantially vertically in the portion that accommodates the encapsulating resin portion, the stepped portion and the small-diameter portion that are extended to the inner diameter side as in the past are provided. It does not exist, and the encapsulating resin portion of the cover member is in an open state.

  Therefore, when filling the encapsulated resin, the injection work is easy, hassle-free, can reduce costs, and the resin spreads over the entire cover constituting the waterproof case, resulting in poor injection and bubbles. As a result, moisture can penetrate from the outside without causing cracks, and it is possible to detect pressure accurately without causing an influence of insulation failure or corrosion on the pressure detection element.

FIG. 1 is a longitudinal sectional view of a pressure sensor of the present invention. FIG. 2 is a partially enlarged longitudinal sectional view of the pressure sensor of the present invention shown in FIG. FIG. 3 is a longitudinal sectional view of another embodiment of the pressure sensor of the present invention. 4 is a partially enlarged longitudinal sectional view of the pressure sensor of the present invention shown in FIG. FIG. 5 is a diagram showing a stress analysis. FIG. 6 is a longitudinal sectional view showing a conventional liquid ring type pressure sensor 100.

  Hereinafter, embodiments (examples) of the present invention will be described in more detail with reference to the drawings.

  1 is a longitudinal sectional view of the pressure sensor of the present invention, and FIG. 2 is a partially enlarged longitudinal sectional view of the pressure sensor of the present invention of FIG.

  1-2, the code | symbol 10 has shown the pressure sensor of this invention on the whole.

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

  And the pressure detection element 16 is arrange | positioned so that the flow path 12 of this joint member 14 may be faced, and the joint member 14 is welded and fixed by the peripheral part.

  The pressure detection element 16 includes an element main body 18 made of, for example, stainless steel or aluminum, and a hermetic glass 22 is fitted and fixed in a central opening 20 formed in the element main body 18.

  Further, as shown in FIG. 1, the element main body 18 of the pressure detection element 16, the metal diaphragm 24, and the diaphragm protective cover 28 in which the communication hole 26 is formed are integrated by welding at their outer peripheral edge portions. Fixed.

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

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

  The sensor chip 32 is disposed in the liquid sealing chamber 30, and is a pressure in which a pressure element for detecting pressure and an integrated electronic circuit for processing an output signal of the pressure detection element are integrally formed. It is configured as a sensor chip.

A plurality of lead pins 34 for inputting / outputting signals to / from the sensor chip 32 are fixed to the hermetic glass 22 by a hermetic 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), 62c (GND), which will be described later as input / output terminals, and five lead pins as adjustment terminals for the sensor chip 32 34 is provided.

  The lead pin 34 is electrically connected (wire bonded) to the sensor chip 32 by, for example, a gold or aluminum wire 36 to constitute an external output terminal or an external input terminal of the sensor chip 32.

  The fluid pressure transmitted from the flow path 12 of the joint member 14 into the pressure chamber 40 presses the surface of the diaphragm 24 through the communication hole 26 of the diaphragm protection cover 28, and this pressing force is applied to the liquid sealing chamber 30. This is detected by the sensor chip 32.

  Further, as shown in FIG. 1, a substrate 38 is provided above the pressure detection element 16 at a predetermined interval, and passes through a through hole 38a formed at one end of the substrate 38. Further, the tip 34a of the lead pin 34 is inserted, and is electrically connected to a circuit (not shown) of the substrate 38 by, for example, soldering.

  On the other hand, an external lead wire 54 is electrically connected to a circuit (not shown) of the substrate 38 by soldering, for example, at the other end of the substrate 38.

  Further, as shown in FIG. 1, the base end portion 44 of the cover member 42 is attached in a state where the flange portion 14 a of the joint member 14 is in contact. The base end portion 44 of the cover member 42 and the flange portion 14a of the joint member 14 are fixed by, for example, soldering, welding, 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 were adhered, it is also possible to fit and attach.

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

  Further, as shown in FIG. 1, the cover member 42 has a cylindrical shape in which the encapsulating resin accommodating portion 48 constitutes a portion erected substantially vertically and has an opening 50 above it. Yes.

  In this case, the “substantially vertical” in the sense that the shape of the cover member 42 is a portion that is erected substantially vertically in the encapsulating resin accommodating portion 48 that is the portion that accommodates the encapsulating resin portion 52 is shown in FIG. As shown, for example, the angle α formed between the upper surface 18a of the element body 18 of the pressure detection element 16 and the encapsulating resin accommodating portion 48 is in the vicinity of 90 °, preferably within ± 1 ° of 90 °. If it is, the effect mentioned later can be produced.

  Thus, as shown in FIG. 1, a gap S is formed inside the encapsulating resin accommodating portion 48 of the cover member 42, and an adhesive is formed in the gap S from the opening 50 side of the cover member 42. An encapsulating resin portion 52 is formed.

  In the pressure sensor 10 of the present invention configured as described above, as shown in FIG. 1, the cover member 42 is erected substantially vertically in the encapsulating resin accommodating portion 48 that is the portion accommodating the encapsulating resin portion 52. This is a cylindrical shape provided with a substantially vertically erected portion, so that there is no step portion extending toward the inner diameter side as in the prior art, and the encapsulating resin portion 52 of the cover member 42 is not present. Is open.

  Therefore, even when the encapsulating resin expands due to heat or when the encapsulating resin cools and contracts, the encapsulating resin portion 52 and the element main body 18 of the pressure detection element 16 can be connected as shown in FIG. There is no delamination due to thermal stress between the gaps (portion A surrounded by the oval shape in FIG. 2), moisture does not enter from the outside, and there is no influence of insulation failure or corrosion on the pressure detection element. , Accurate pressure detection can be performed.

  Further, as shown in FIG. 1, the cover member 42 has a cylindrical shape including a portion that is erected substantially vertically in the encapsulating resin housing portion 48 that is a portion that houses the encapsulating resin portion 52. As described above, the stepped portion and the small-diameter portion that extend toward the inner diameter side do not exist, and the encapsulated resin portion 52 enclosed in the gap S inside the encapsulated resin accommodating portion 48 of the cover member 42 is the opening of the cover member 42. The part 50 is open.

  Therefore, when filling the encapsulating resin, the injecting operation is easy, less time-consuming, the cost can be reduced, and the resin spreads over the entire cover member 42 constituting the waterproof case, resulting in incomplete injection or bubbles. It does not occur and cracks do not occur, and moisture enters from the outside, so that the pressure can be accurately detected without causing an insulation failure or corrosion on the pressure detection element 16.

  3 is a longitudinal sectional view of another embodiment of the pressure sensor of the present invention, FIG. 4 is a partially enlarged longitudinal sectional view of the pressure sensor of the present invention of FIG. 3, and FIG. 5 is a diagram showing stress analysis.

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

  In the pressure sensor 10 according to the first embodiment shown in FIGS. 1 and 2, the substrate 38 is provided above the pressure detection element 16 at a predetermined interval.

  In contrast, in the pressure sensor 10 of this embodiment, as shown in FIGS. 3 to 4, the pressure detection element 16 and the substrate 38 to which the external lead wire 54 is connected are arranged in contact with each other. ing.

  By configuring in this way, as shown in FIGS. 3 to 4, the pressure detection element 16 and the substrate 38 to which the external lead wire 54 is connected are arranged in contact with each other. There is no gap between the element 16 and the substrate 38 connecting the external lead 54. For this reason, even when the encapsulating resin constituting the adhesive is injected, the encapsulating resin portion 52 does not exist between the pressure detection element 16 and the substrate 38 to which the external lead wire 54 is connected.

  Therefore, when the encapsulating resin expands due to heat or when the encapsulating resin cools and contracts, no thermal stress is generated between the pressure detection element 16 and the substrate connecting the external lead wire 54. The substrate 38 and the pressure detection element 16 are not damaged and damaged, and the pressure can be reliably detected.

  Further, since no thermal stress is generated between the pressure detection element 16 and the substrate 38 to which the external lead wire 54 is connected, the connection portion between the pressure detection element 16 and the lead pin 34 that connects the substrate 38 (the tip of the lead pin 34). 34a) is damaged and the electrical connection is cut off, and the connection portion (54a) connecting the substrate 38 and the external lead wire 54 is not damaged and the electric connection is not cut off. Detection can be performed.

  Further, as shown in FIGS. 3 to 4, since the pressure detection element 16 and the substrate 38 to which the external lead wire 54 is connected are arranged in contact with each other, the pressure detection element 16 and the external lead are arranged. There is no gap between substrate 38 connecting line 54. For this reason, the amount of encapsulating resin constituting the adhesive can be reduced, the cost can be reduced, and the pressure sensor can be made compact and small.

  FIG. 5 is a diagram showing a stress analysis when the temperature is changed from 100 ° C. to −40 ° C. As shown in FIG. 5 (A), a waterproof case is configured like the pressure sensor 100 of Patent Document 1. The shape of the cover member 106 includes a cover main body portion 120a having a large diameter portion, a step portion 120b extending to the inner diameter side, and a small diameter portion 120c standing upright from the step portion 120b. In the structure, the stress value is as large as 21 MPa between the encapsulating resin 122 and the element main body 126 of the pressure detection element 102.

  On the other hand, as shown in FIG. 5 (B), as in the pressure sensor 10 of the present invention, the encapsulating resin in which the shape of the cover member 42 constituting the waterproof case is a portion that accommodates the encapsulating resin portion 52. In the accommodating part 48, it is a part set up substantially vertically, and when it is a cylinder shape provided with the part set up substantially vertically, a stress value can be reduced to about 1/3 with 6MPa. I understand.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to this. For example, in the above embodiment, the cover member 42 is a base that contacts the flange portion 14a of the joint member 14. An end 44, an element main body fitting portion 46 that fits into the element main body 18 of the pressure detection element 16, and an encapsulated resin accommodating portion 48 that accommodates the encapsulating resin portion 52 with a slightly smaller diameter than the element main body fitting portion 46. However, various modifications can be made without departing from the object of the present invention, for example, it is possible to form a cover member which is constituted by separate members and fixed to each other.

  The present invention can be applied to a liquid ring type pressure sensor.

DESCRIPTION OF SYMBOLS 10 Pressure sensor 12 Flow path 14 Joint member 14a Flange part 16 Pressure detection element 18 Element main body 18a Upper surface 20 Center opening 22 Hermetic glass 24 Diaphragm 26 Communication hole 28 Diaphragm protective cover 30 Liquid seal chamber 32 Sensor chip 34 Lead pin 34a Tip 36 Wire 38 Substrate 38a Through hole 40 Pressure chamber 42 Cover member 44 Base end portion 46 Element body fitting portion 48 Encapsulated resin accommodating portion 50 Opening portion 52 Encapsulated resin portion 54 External lead wire 100 Pressure sensor 102 Pressure detection element 104 Joint member 106 Cover member 108 Diaphragm 110 Sensor chip 112 Wire bonding 114 Lead pin 116 Substrate 118 External lead wire 120a Cover main body 120b Stepped portion 120c Small diameter portion 122 Encapsulated resin 124 Encapsulated Fat-126 element main body

Claims (2)

A joint member in which a flow path is formed;
In order to detect the pressure of the fluid in the flow path, a pressure detection element fixed to the joint member and disposed so as to face the flow path of the joint member;
An external lead connected to the pressure sensing element;
An encapsulating resin portion that fills a gap formed inside the cover member and constitutes an adhesive;
With
The pressure sensor according to claim 1, wherein the cover member has a cylindrical shape including a portion that is erected substantially vertically in a portion that accommodates the encapsulating resin portion.   The pressure sensor according to claim 1, wherein the pressure detection element and a substrate to which an external lead wire is connected are arranged in contact with each other.

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