JP6461862B2 - Pressure sensor and method of manufacturing pressure sensor - Google Patents

Description

  The present invention relates to a pressure sensor and a method for manufacturing the pressure sensor.

  A sensor unit that constitutes a part of a liquid-seal type semiconductor pressure sensor is, for example, a pressure detection formed inside a metal joint connected to a housing in a cover as disclosed in Patent Document 1. It is arranged indoors. Such a sensor unit includes, for example, a diaphragm that is supported in a joint portion and separates the above-described pressure detection chamber from a liquid sealing chamber described later, and a liquid seal that is formed above the diaphragm and stores silicone oil as a pressure transmission medium. Chamber, a sensor chip that is arranged in the liquid seal chamber and detects the pressure fluctuation of the silicone oil through the diaphragm, a chip mount member (base) that supports the sensor chip, and the output of the output signal from the sensor chip to the sensor chip A plurality of lead pins for supplying power are included as main elements. The above-described lead pin is fixed in the hermetic glass of the chip mount member and is electrically connected to the external lead wire. An inner space formed above the chip mount member in the cover surrounding the chip mount member is filled with an adhesive. Accordingly, the filled adhesive is adhered to the inner peripheral surface of the cover and the outer peripheral portion of the external lead wire, so that the liquid can be prevented from entering the cover from the outside.

  In addition, when a thermosetting resin is filled as an adhesive in an inner space formed above the chip mount member in the cover surrounding the chip mount member, as shown in Patent Document 2, the filled heat curing is performed. In the upper end portion of the resin of the mold, a concave portion may be formed by the shrinkage of the resin after curing. In such a case, in order to avoid the dew in the atmosphere from accumulating in the above-described recess depending on the mounting posture of the pressure sensor, a convex covering layer may be formed to fill the recess as a sealing material. Proposed.

JP 2012-68105 A International Publication No. 2015/194105

  As described above, in addition, the operation of forming a convex covering layer as a sealing material so as to fill the concave portion is complicated at the time of mass production, resulting in a decrease in production efficiency. In such a case, it may be possible to predict the amount of shrinkage of the resin after the resin has been cured in advance, and to add an excessive amount of heat-curing type resin. However, the amount of resin filling increases, which increases the manufacturing cost. It's not a good idea.

  In view of the above problems, the present invention is a pressure sensor that can avoid a situation in which a concave portion due to resin shrinkage is formed after curing without increasing the amount of resin filling as a sealing material. An object of the present invention is to provide a sensor and a method for manufacturing a pressure sensor.

In order to achieve the above-described object, a pressure sensor according to the present invention includes a sensor unit including a sensor chip for detecting pressure, a cover member having a sensor unit housing portion for housing the sensor unit, and a sensor unit housing for the cover member. A sealing material made of a urethane resin material filled around the sensor unit in the portion, and an end cap that is disposed in the sensor unit housing portion of the cover member and protrudes upward from the opening end of the cover member , The top of the end face of the sealing material exposed to the outside from the opening of the cover member is bonded to the vicinity of the upper end face of the end cap and directed upward according to the shrinkage ratio of the hardened sealing material with respect to the skirt of the end face. It is characterized by being formed in a substantially conical surface that is convex .

Further, the lead wire that is electrically connected to the sensor chip and protrudes from the end face of the sealing material may be inserted into the sealing material at a portion that is electrically connected to the sensor chip . The top of the end face of the sealing material may be formed with a height difference of 0.5 mm or more with respect to the skirt of the end face. A lead wire protruding from the end face of the sealing material may be inserted into the sealing material with a length of 4 mm or more .

The pressure sensor manufacturing method according to the present invention includes a sensor unit including a sensor chip for detecting pressure, and an end cap connected to the sensor unit in a sensor unit housing portion of a cover member, and a sealing material made of a urethane resin material. Filling the periphery of the sensor unit in the sensor unit housing portion of the cover member with a dispenser, and one end of the dispenser is disposed in the vicinity of the outer peripheral edge of the end cap in the sensor unit housing portion of the cover member. The top portion of the end surface of the sealing material exposed to the outside is bonded to the vicinity of the upper end surface of the end cap, and is approximately convex upward depending on the shrinkage rate of the sealing material cured with respect to the hem portion of the end surface. It is formed in the shape of a conical surface .

According to the pressure sensor and the manufacturing method of the pressure sensor according to the present invention, the top portion of the end surface of the sealing material exposed to the outside from the opening of the cover member is bonded to the vicinity of the upper end surface of the end cap, and the bottom of the end surface It is formed in a substantially conical surface that is convex upward depending on the shrinkage rate of the sealing material cured with respect to the part, so that the resin after curing without increasing the filling amount of the resin as the sealing material It is possible to avoid a situation in which a recess is formed due to the shrinkage.

1 is a cross-sectional view showing the overall configuration of a first embodiment of a pressure sensor according to the present invention. It is sectional drawing which shows the whole structure in 2nd Example of the pressure sensor which concerns on this invention.

  FIG. 1 schematically shows a first embodiment of a pressure sensor according to the invention.

  In FIG. 1, the pressure sensor contains a joint member 30 connected to a pipe through which a fluid whose pressure is to be detected is guided, and a sensor unit connected to a base plate 28 of the joint member 30, and a detection output from the sensor chip. And a sensor unit housing for supplying a signal to a predetermined pressure measuring device.

  The metal joint member 30 has an internal thread portion 30fs that is screwed into the external thread portion of the connection portion of the pipe described above. The female screw portion 30fs communicates with the port 30a of the joint member 30 that guides the fluid supplied from the direction indicated by the arrow P to the pressure chamber 28A described later. One open end of the port 30a opens toward a pressure chamber 28A formed between the base plate 28 of the joint member 30 and the diaphragm 32 of the sensor unit.

  The outer portion of the sensor unit housing portion is formed by a cylindrical waterproof case 20 as a cover member. An opening 20 b is formed at the lower end of the resin waterproof case 20. The peripheral edge of the base plate 28 of the joint member 30 is engaged with the step portion on the peripheral edge of the opening 20b that is the inner side.

  Air or liquid as a fluid is supplied into the pressure chamber 28 </ b> A through the port 30 a of the joint member 30. A lower end surface of the housing 12 of the sensor unit is placed on the base plate 28.

  The sensor unit that detects the pressure in the pressure chamber 28A and sends out a detection output signal includes a cylindrical housing 12, a metal diaphragm 32 that isolates the pressure chamber 28A and the inner periphery of the housing 12, and a plurality of pressures. A sensor chip 16 having a detection element, a metal chip mount member 18 that supports the sensor chip 16 at one end via a glass layer, and an input / output terminal group 40ai (i = 1-8) and the hermetic glass 14 for fixing the input / output terminal group 40ai and the oil filling pipe 44 between the outer peripheral surface of the chip mount member 18 and the inner peripheral surface of the housing 12 as main elements. It is configured.

  The diaphragm 32 is supported on one lower end surface of the housing 12 facing the pressure chamber 28A. The diaphragm protection cover 34 that protects the diaphragm 32 disposed in the pressure chamber 28A has a plurality of communication holes 34a. The peripheral edge of the diaphragm protection cover 34 is joined to the lower end surface of the stainless steel housing 12 by welding together with the peripheral edge of the diaphragm 32.

  In the liquid sealing chamber formed between the sensor chip 16 facing the metal diaphragm 32 and the end face of the hermetic glass 14, for example, a predetermined amount of silicone oil PM or a fluorine-based inert liquid is used as a pressure transmission medium. It is filled through an oil filling pipe 44. Note that one end of the oil filling pipe 44 is crushed and closed as indicated by a two-dot chain line after oil filling.

  The silicone oil is, for example, a silicone oil having a dimethylpolysiloxane structure composed of a siloxane bond and an organic methyl group. The fluorine-based inert liquid is, for example, a liquid having a perfluorocarbon structure, a liquid having a hydrofluoroether structure, or a low polymer of ethylene trifluoride chloride, and fluorine and chlorine are bonded to the main chain. , Both ends may have a fluorine or chlorine structure.

  Between the sensor chip 16 and the diaphragm 32 disposed in the recess formed at the end of the hermetic glass 14, a metal potential adjusting member 17 is further supported on the lower end surface of the hermetic glass 14. The potential adjusting member 17 is connected to a terminal having a communication hole and connected to the zero potential of the circuit of the sensor chip 16 as disclosed in, for example, Japanese Patent No. 3987386.

  The input / output terminal group 40ai (i = 1 to 8) includes two power supply terminals, one output terminal, and five adjustment terminals. Both end portions of each terminal protrude toward a recess formed at the end portion of the above-described hermetic glass 14 and a hole of a terminal block 24 described later. The two power supply terminals and the one output terminal are connected to the core wires 38 a of the lead wires 38 via the connection terminals 36. Each lead wire 38 is connected to a predetermined pressure measuring device. In FIG. 1, only four of the eight terminals are shown.

  The sensor chip 16 includes a plurality of pressure detection elements, for example, a main body formed in a substantially rectangular shape with silicon, a circuit layer formed on the upper end surface of the main body to form a processing circuit, and a first An insulating film layer as a second layer laminated on the upper surface of the circuit layer as a layer, an aluminum shield layer formed on the insulating film layer, and a protective layer protecting the upper layer portion of the shield layer It consists of

  In the above-described example, the sensor chip 16 in the sensor unit is supported by one end of the chip mount member 18 held in the hermetic glass 14, but is not limited to such an example. 16 may be configured to be directly fixed to the flat surface forming the concave portion of the hermetic glass 14 without using the chip mount member 18.

  The terminal block 24 for aligning the input / output terminal groups 40ai is formed of a resin material, for example, polybutylene terephthalate (PBT). The terminal block 24 includes a plurality of holes into which the input / output terminal group 40ai is inserted and a hollow portion having a predetermined volume inside. The lower end surface of the terminal block 24 is bonded to the upper end surface of the housing 12 with a silicone-based adhesive so as to cover the upper end surface of the hermetic glass 14. As a result, an annular adhesive layer having a predetermined thickness is formed on the upper end surface of the housing 12. Further, a coating layer made of a silicone-based adhesive is formed with a predetermined thickness on the entire upper end surface of the hermetic glass 14 from which the input / output terminal group 40ai projects. As a result, the silicone adhesive layer 10 is formed on the upper end surface of the housing 12 and the entire upper end surface of the hermetic glass 14.

  Therefore, the silicone adhesive layer 10 is formed as an electrostatic protection layer. By forming the electrostatic protection layer 10 with the silicone-based adhesive in this way, the electrostatic strength of the sensor unit is improved without being affected by the presence or absence of the ESD protection circuit.

  The above-mentioned silicone adhesive is preferably, for example, a flexible addition type one-component system. The silicone-based adhesive is, for example, an adhesive having a low molecular siloxane bond. Further, since the silicone adhesive and the silicone oil are compatible, there is no possibility that the adhesiveness of the silicone adhesive will deteriorate even if silicone oil or the like is mixed in the silicone adhesive.

  Between the outer peripheral surface of the terminal block 24, the outer peripheral surface of the end cap 22 connected to the terminal block 24 and covering the above-described hole, and the inner peripheral surface of the waterproof case 20, and the inner peripheral surface of the waterproof case 20 and the housing 12 A predetermined amount of the sealing material 26 is filled between the outer peripheral surface and the outer peripheral surface. The terminal block 24 and the end cap 22 are disposed in the waterproof case 20 so as to face the base plate 28 of the joint member 30 with the above-described sensor unit interposed therebetween.

  The upper end surface of the end cap 22 protrudes upward from the opening end of the waterproof case 20. That is, the position of the upper end surface of the end cap 22 is higher than the position of the opening end surface of the waterproof case 20.

  The sealing material 26 is a thermosetting resin material, such as a urethane resin or an epoxy resin. The position of the top portion 26I that is closest to the center axis of the end cap 22 in the sealing material 26 (that is, the center axis of the waterproof case 20) and is bonded to the vicinity of the upper end surface of the end cap 22 is the most relative to the center axis of the end cap 22. It is set with a predetermined height difference ΔHA with respect to the position of the skirt portion 26E bonded in the vicinity of the opening end surface formed substantially perpendicular to the inner peripheral surface 20a of the separated waterproof case 20. The height difference ΔHA is set to, for example, at least 0.5 mm according to the shrinkage rate of the cured sealing material 26. Thereby, without increasing the filling amount of the sealing material 26 filled in the waterproof case 20, a concave portion in which water droplets such as dew are accumulated is not formed on the upper surface of the sealing material 26 exposed to the outside. At that time, the core wire 38 a and the covering of the lead wire 38 are inserted into the sealing material 26 by, for example, 4 mm or more. In addition, the upper surface exposed to the outside in the sealing material 26 may be formed as a convex surface protruding upward or, for example, a substantially conical surface.

  In an example of the pressure sensor manufacturing method according to the present invention, as described above, the height difference ΔHA is formed after the sensor unit, the end cap 22, the terminal block 24, and the like are arranged in the waterproof case 20. Thus, when the sealing material 26 is filled by a predetermined amount set in advance, the position of the tip of the dispenser 42 that supplies the sealing material 26 into the waterproof case 20 is indicated by a two-dot chain line in FIG. As shown, the end cap 22 is positioned near the upper end surface. Thereby, the situation where the sealing material 26 overflows from the waterproof case 20 during filling is avoided.

  In the case where the sealing material 26 is a urethane-based resin, the surface of the outer peripheral surface of the housing 12 is roughened so as to improve the adhesion between the outer peripheral surface of the housing 12 and the urethane-based resin. Also good. For the roughening treatment, for example, a roughening treatment method disclosed in an international application (PCT / JP2013 / 083351) by the present applicant may be used. The sealing material 26 may be a room temperature curable resin instead of the heat curable resin.

  FIG. 2 schematically shows a second embodiment of a pressure sensor according to the present invention.

  In FIG. 2, the same components as those in the example shown in FIG.

  The pressure sensor is connected to a joint member 30 connected to a pipe through which a fluid whose pressure is to be detected is guided, and a base plate 28 of the joint member 30. The pressure sensor accommodates a sensor unit and measures a detection output signal from the sensor chip to a predetermined pressure. And a sensor unit housing portion to be supplied to the apparatus. The outer portion of the sensor unit housing portion is formed by a cylindrical waterproof case 21 as a cover member. An opening 21 b is formed at the lower end of the resin waterproof case 21. The peripheral edge of the base plate 28 of the joint member 30 is engaged with the step portion on the peripheral edge of the opening 21b which is the inner side. The length H2 along the central axis in the waterproof case 21 is set to be slightly larger than the corresponding length H1 in the waterproof case 20 described above.

  Between the outer peripheral surface of the terminal block 24, the outer peripheral surface of the end cap 22 'that is connected to the terminal block 24 and covers the above-described hole, and the inner peripheral surface of the waterproof case 21, and the inner peripheral surface of the waterproof case 21 and the housing A predetermined amount of sealing material 26 is filled between the outer peripheral surfaces of the twelve. The terminal block 24 and the end cap 22 ′ are arranged in the waterproof case 21 so as to face the base plate 28 of the joint member 30 with the above-described sensor unit interposed therebetween.

  The upper end surface of the end cap 22 ′ protrudes upward from the opening end of the waterproof case 21. That is, the position of the upper end surface of the end cap 22 ′ is higher than the position of the opening end surface of the waterproof case 21. The cavity depth 22′CH in the end cap 22 ′ is set to be larger than the cavity depth in the end cap 22 (see FIG. 1) described above. That is, the height from the connecting portion of the terminal block 24 on the upper end surface of the end cap 22 ′ is set larger than the corresponding height in the end cap 22.

  The position of the top portion 26I that is closest to the center axis of the end cap 22 ′ (that is, the center axis of the waterproof case 21) in the sealing material 26 and is bonded to the vicinity of the upper end surface of the end cap 22 ′ is the center axis of the end cap 22 ′. Is set with a predetermined height difference ΔHB with respect to the position of the skirt portion 26E bonded in the vicinity of the opening end surface formed substantially perpendicular to the inner peripheral surface 21a of the waterproof case 21 that is farthest apart. The height difference ΔHB is set to, for example, at least 0.5 mm or more according to the shrinkage rate of the cured sealing material 26. As a result, a recess in which water droplets such as dew accumulate is not formed on the upper surface of the sealing material 26 exposed to the outside. In addition, the upper surface exposed to the outside in the sealing material 26 may be formed as a convex surface protruding upward or a substantially conical surface. At that time, the core wire 38 a and the covering of the lead wire 38 are inserted into the sealing material 26 by, for example, 4 mm or more.

12 Housing 14 Hermetic glass 16 Sensor chip 18 Chip mounting member 20, 21 Waterproof case 22, 22 'End cap 24 Terminal block 26 Sealing material 38 Lead wire 42 Dispenser

Claims (5)

A sensor unit including a sensor chip for detecting pressure;
A cover member having a sensor unit housing portion for housing the sensor unit;
A sealing material made of a urethane resin material filled around the sensor unit in the sensor unit housing portion of the cover member;
An end cap disposed in the sensor unit housing portion of the cover member and projecting upward from an opening end of the cover member ;
The top portion of the end face of the sealing material exposed to the outside from the opening of the cover member is bonded to the vicinity of the upper end face of the end cap, and depends on the shrinkage rate of the sealing material cured to the skirt portion of the end face. A pressure sensor characterized by being formed in a substantially conical surface that is convex upward . The lead wire electrically connected to the sensor chip and protruding from the end face of the sealing material is inserted into the sealing material at a portion electrically connected to the sensor chip. The pressure sensor according to claim 1. 2. The pressure sensor according to claim 1, wherein the top portion of the end surface of the sealing material is formed with a height difference of 0.5 mm or more with respect to the skirt portion of the end surface . The pressure sensor according to claim 2, wherein a lead wire protruding from an end face of the sealing material is inserted into the sealing material with a length of 4 mm or more . A sensor unit including a sensor chip for detecting pressure and an end cap connected to the sensor unit are arranged in the sensor unit housing portion of the cover member,
Filling a sealant made of a urethane resin material around the sensor unit in the sensor unit housing portion of the cover member with a dispenser,
One end of the dispenser is disposed in the vicinity of the outer peripheral edge of the end cap in the sensor unit housing portion of the cover member, and the top of the end surface of the sealing material exposed from the opening of the cover member to the outside is above the end cap. Manufacturing of a pressure sensor, characterized in that it is formed in a substantially conical surface shape that protrudes upward according to the shrinkage rate of the sealing material that is bonded to the vicinity of the end surface and hardened to the skirt portion of the end surface Way .

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