阅读说明：本技术 压力检测单元和使用该压力检测单元的压力传感器 (Pressure detection unit and pressure sensor using the same ) 是由 向井元桐 青山伦久 高月修 于 2019-06-27 设计创作，主要内容包括：本发明提供一种能够实现输出值的稳定化和小型化并且降低成本的压力检测单元和压力传感器。压力检测单元具有：膜片(50),该膜片(50)承受流体的压力；基座(40),在该基座(40)与所述膜片(50)之间形成封入有介质的受压空间(S1)；压力检测装置(60),该压力检测装置(60)在所述受压空间(S1)内配置于所述基座(40),并且对传递到所述介质的压力进行检测并转换为电压力信号；以及多个端子销(70～74),该多个端子销(70～74)用于在所述压力检测装置(60)与外部的电路之间进行电连接,在所述膜片(50)和所述基座(40)的面向所述受压空间(S1)的部位形成绝缘层。(The invention provides a pressure detection unit and a pressure sensor, which can realize stabilization and miniaturization of output values and reduce cost. The pressure detection unit has: a diaphragm (50), the diaphragm (50) being subjected to a pressure of the fluid; a base (40) in which a pressure receiving space (S1) in which a medium is sealed is formed between the base (40) and the diaphragm (50); a pressure detection device (60) which is disposed on the base (40) in the pressure receiving space (S1), detects the pressure transmitted to the medium, and converts the pressure into an electric pressure signal; and a plurality of terminal pins (70-74), wherein the terminal pins (70-74) are used for electrically connecting the pressure detection device (60) and an external circuit, and an insulating layer is formed on the diaphragm (50) and the base (40) at the position facing the pressure receiving space (S1).)

1. A pressure detection unit is characterized by comprising:

a diaphragm that receives a pressure of the fluid;

a base forming a pressure receiving space in which a medium is sealed between the base and the diaphragm;

a pressure detection device that is disposed on the base in the pressure receiving space, and that detects and converts a pressure in the pressure receiving space into an electric signal; and

a plurality of terminal pins for making electrical connection between the pressure detection device and an external circuit,

an insulating layer is formed on the diaphragm and the base at a portion facing the pressure receiving space.

2. Pressure detection unit according to claim 1,

the insulating layer is a film containing an epoxy resin or an organic silicon as a main component.

3. Pressure detection unit according to claim 1,

the insulating layer is an insulating plating layer.

4. Pressure detection unit according to one of the claims 1 to 3,

the base is made of steel and is welded to a support member facing the base with the diaphragm interposed therebetween, and the insulating layer is formed on a surface of the base facing the pressure receiving space.

5. Pressure detection unit according to one of the claims 1 to 4,

the base is made of ceramic, ring members facing the base through the diaphragm and the terminal pins inserted into the through holes of the base are soldered to the base, and the insulating layer is formed on the surface of the solder attached to the surface of the base on the pressure receiving space side.

6. Pressure detection unit according to claim 5,

the terminal pin is inserted into and soldered to the through hole of the base, and the insulating layer is formed on a soldering surface of the base facing the terminal pin.

7. A pressure sensor, characterized in that,

use of a pressure detection unit according to any of claims 1 to 6.

Technical Field

The present invention relates to a pressure detection unit and a pressure sensor using the same.

Background

In order to detect the refrigerant pressure by being installed in a refrigerating and freezing apparatus or an air conditioning apparatus, or to detect various fluid pressures by being installed in an industrial facility, a pressure sensor provided with a pressure detection device is used. In one type of such a pressure detection device, a sensor chip as the pressure detection device is disposed in a pressure receiving chamber partitioned by a diaphragm and sealed with oil, and thus has a function of converting a pressure change in the pressure receiving chamber into a voltage force signal and outputting the voltage force signal to the outside.

However, in this type of pressure sensor, the output value may be affected due to static electrification for some reason.

Therefore, the following patent documents disclose the following: in the pressure receiving space in which oil is sealed, particularly, a conductive member is disposed between the sensor chip and the diaphragm, and the conductive member is connected to a zero potential of a circuit in the sensor chip to remove electricity.

Disclosure of Invention

An object of the present invention is to provide a pressure detecting unit and a pressure sensor capable of achieving stabilization and miniaturization of an output value and reducing cost.

Means for solving the problems

In order to achieve the above object, a pressure detection unit according to the present invention includes:

a diaphragm that receives a pressure of the fluid;

a base forming a pressure receiving space in which a medium is sealed between the base and the diaphragm;

a pressure detection device that is disposed on the base in the pressure receiving space, and that detects and converts a pressure in the pressure receiving space into an electric signal; and

a plurality of terminal pins for making electrical connection between the pressure detection device and an external circuit,

an insulating layer is formed on the diaphragm and the base at a portion facing the pressure receiving space.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a pressure detecting unit and a pressure sensor that can realize stabilization and miniaturization of an output value and reduce cost.

Drawings

Fig. 1 is a plan view of a pressure detection unit according to a first embodiment of the present invention.

Fig. 2 is a side view showing a cross section taken along line X-X in fig. 1.

Fig. 3 is a cross-sectional view of the structure of fig. 2, taken along the line a-a and viewed in the direction of the arrows.

Fig. 4 is a cross-sectional view of the structure of fig. 2, taken along the line B-B and viewed in the direction of the arrows.

Fig. 5 is a longitudinal sectional view showing an embodiment of the pressure sensor.

Fig. 6 is a cross-sectional view corresponding to fig. 5 of a first modification.

Fig. 7 is a longitudinal sectional view of a pressure detection unit 2A of a second modification.

Fig. 8 is a view of a cross section along line C-C of fig. 7 viewed in a viewing direction.

Fig. 9 is a vertical cross-sectional view of a pressure detection unit 2B of a third modification.

Fig. 10 is a view of a cross section along line D-D of fig. 9 viewed in a viewing direction.

Fig. 11 is a vertical cross-sectional view of a pressure detection unit 2C according to a fourth modification.

Fig. 12 is a view of a cross section along line E-E of fig. 11 viewed in a viewing direction.

Fig. 13 is a longitudinal sectional view of a pressure detection unit 2D of a fifth modification.

Fig. 14 is a view of a cross section along line G-G of fig. 13 viewed in a viewing direction.

Fig. 15 is a plan view of a pressure detection unit according to a second embodiment of the present invention.

Fig. 16 is a side view of the cross section taken along line H-H in fig. 15.

Fig. 17 is a longitudinal sectional view of the pressure sensor to which the pressure detection unit of the second embodiment is attached.

Fig. 18 is a sectional view of a pressure sensor to which a pressure detection unit of the third embodiment is attached.

Description of the symbols

1. 1A, 1B, 1C pressure sensor

2. 2A-2D, 100A, 100B pressure detection unit

10 cover

20 fluid inflow pipe

30. 120 support member

40. 110 base

50. 130 diaphragm

60. 150 pressure detection device

70. 72, 74 terminal pin

160. 162, 164 terminal pin

40c seal

80 static eliminating plate

90 relay substrate

92 connector

94 lead wire

140 Ring component

240 male connector

250 rivet holding member

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

< first embodiment >

Fig. 1 is a plan view of a pressure detection unit according to a first embodiment of the present invention, and fig. 2 is a cross-section taken along line X-X of fig. 1 as viewed from the side.

In fig. 2, the pressure detection unit 2 includes: a bowl-shaped support member 30 for supporting the fluid inlet pipe 20 to which a fluid inlet pipe, not shown, is connected, by the support member 30; a bowl-shaped base 40, the base 40 being disposed opposite the support member 30; and a metal diaphragm 50, an outer periphery of the diaphragm 50 being held between the support member 30 and the base 40. The support member 30, the base 40, and the diaphragm 50 are formed of, for example, a stainless alloy, and the outer peripheries of these structures are integrally formed by welding W.

The base 40 includes a disc-shaped main body 41, a flange 42, and an annular connecting portion 43 connecting the main body 41 and the flange 42. That is, the base 40 is formed in a shape in which the center portion of the lower surface is recessed in fig. 2 so as to form a pressure receiving space S1 described later.

A sealed pressure receiving space S1 is formed between the base 40 and the diaphragm 50, and the pressure receiving space S1 is filled with an insulating liquid medium such as oil. A semiconductor-type pressure detection device 60, which will be described later, is attached to the center of the body 41 inside the connection portion 43 on the pressure receiving space S1 side.

As shown in fig. 1, three through holes 40a into which three terminal pins 70, 72, and 74 are inserted and a hole 40b (shown by a broken line) for injecting a medium are formed in the base 40 at positions around the pressure detector 60.

The three terminal pins 70, 72, and 74 are inserted into the through holes 40a provided in the base 40 to penetrate the base 40, and the lower ends of the terminal pins are electrically connected to the semiconductor-type pressure detection device 60. A seal 40c is provided between the terminal pins 70, 72, and 74 and the through hole 40a, and seals the pressure receiving space S1. After the medium is injected into the pressure receiving space S1, the hole 40b is shielded by the metal ball 40d, and the ball 40d is welded to the base 40 to seal the hole 40 b.

In fig. 2, the support member 30 is formed of a metal material such as a stainless steel plate, for example, and is formed by press-molding into a bowl shape with a depressed central portion, and has a circular bottom portion 31, a conical portion 32 extending upward from an outer edge of the circular bottom portion 31, and a flange portion 33 extending in a horizontal direction from an outer edge of the conical portion 32.

An opening 34 for attaching a fluid inlet pipe, which will be described later, is formed in the center of the circular bottom portion 31, and a diaphragm 50 is joined to the upper surface of the flange portion 33. With such a configuration, a pressurized space S2 into which a fluid to be detected flows is formed between the support member 30 and the diaphragm 50.

The diaphragm 50 is a disk-shaped thin plate member made of a metal material such as stainless steel.

The pressure detection device 60 is die-bonded to the center portion of the base 40 by bonding or the like. The pressure detection device 60 is composed of a support substrate 62 made of glass and a pressure detection element (semiconductor chip) 64 bonded thereto.

The pressure detection device 60 includes, for example, eight pads (electrodes) on the surface of the pressure detection element 64. Referring to fig. 3 described later, three pads are a power input pad 64a, a ground pad 64b, and a signal output pad 64c for outputting signals, and the remaining five pads are signal adjustment pads 64 d.

Fig. 3 is a cross-sectional view of the structure of fig. 2, taken along the line a-a, and fig. 4 is a cross-sectional view of the structure of fig. 2, taken along the line B-B, taken along the direction of the arrows. In the present embodiment, the surfaces of the main body 41, the connecting portion 43, and the flange portion 42 of the base 40 exposed to the pressure receiving space S1 are covered with an insulating layer IS (indicated by double-hatching in fig. 3). However, the vicinity of the pressure detection device 60 IS covered by the insulating layer IS. The insulating layer IS may be covered on the surface of the pressure detecting element 64.

The surface (entire surface) of the diaphragm 50 exposed to the pressure receiving space S1 IS also covered with an insulating layer IS (indicated by double hatching in fig. 4).

The insulating layer IS a film mainly composed of an epoxy resin or silicone insoluble in a medium, or an insulating plating (manganese phosphate treatment or the like).

< assembling Process of pressure detecting Unit >

The process of assembling the pressure detection unit 2 will be described below. As a pre-process, an epoxy adhesive is thinly applied to the surface of the base 40 exposed to the pressure receiving space S1 and the surface of the diaphragm 50 exposed to the pressure receiving space S1, and cured. Next, the terminal pin 70 for power input, the terminal pin 72 for grounding, and the terminal pin 74 for signal output are inserted through the through hole 40a formed in the base 40, and the three terminal pins 70, 72, and 74 are joined and fixed to the base 40 by the sealing member 40 c.

Next, the pressure detection device 60 is die-bonded to the central portion of the base 40. Then, the power input pad 64a, the ground pad 64b, and the signal output pad 64c of the pressure detection device 60 are electrically connected to one end of each of the three terminal pins 70, 72, and 74 via the connection wire 76.

Before the liquid medium is injected, the probes for energization are brought into contact with the eight pads 64a to 64d of the pressure detection element 64 of the pressure detection device 60 exposed in the base 40, respectively, to perform the temperature correction operation (trimming operation) of the pressure detection element 64, thereby reducing the number of terminal pins to three. This increases the diameter of the seal 40c, increases the degree of freedom of arrangement, and can obtain an insulation distance. However, eight terminal pins may be provided, the number of which is the same as the number of pads.

Here, in a state where a load (pressure) is applied to the pressure detection element 64 at a reference temperature (for example, room temperature), an output value output from the signal output pad 64c or the signal adjustment pad 64d is read, and a predetermined correlation between the pressure and the output is obtained to set a correction coefficient (correction function).

Thereafter, the diaphragm 50 is sandwiched between the support member 30 and the base 40, a liquid medium is filled into the pressure receiving space S1 formed between the base 40 and the diaphragm 50 through the hole 40b, and the ball 40d is sealed by welding to the base 40 while being shielded by the ball 40 d.

In this case, the overlapping portion of the support member 30 and the ring member 40 is irradiated with laser light from the outer circumferential direction and relatively rotated, and circumferential welding (forming the welded portion W) is continuously performed to integrate them. Thereby, the support member 30, the diaphragm 50, and the base 40 are integrated.

Further, as a method of peripheral welding, welding such as arc welding or resistance welding such as seam welding can be applied without being limited to laser welding, but when reducing the strain of welding or the like, laser welding with a small heat input, electron beam welding or the like is preferably applied.

< pressure sensor >

Fig. 5 is a longitudinal sectional view showing an embodiment of the pressure sensor. As shown in fig. 5, the pressure sensor 1 includes a resin cover 10, and the cover 10 has the following shape: the large diameter portion 10a having a circular tube shape in cross section and the small diameter portion 10b having an annular, oblong, elliptical or the like in cross section are coaxially aligned, and respective end portions are joined to each other via the step portion 10 c. The pressure detection unit 2 is attached to the inside of the large diameter portion 10a of the cover 10.

A cylindrical portion 20a is formed to protrude from the upper end of the fluid inlet pipe 20, and the cylindrical portion 20a is sealingly fitted and fixed to an opening 34 formed in the center of the support member 30 by brazing or the like. A through passage 20b is formed inside the cylindrical portion 20a, and the pressurized space S2 inside the support member 30 and the inside of the fluid inflow pipe 20 are communicated with each other through the through passage 20 b.

Three terminal pins (only reference numeral 70) of the pressure detection unit 2 are connected to the wiring of the relay substrate 90.

The lead wire 94 is connected to a circuit, not shown, in a control panel of a refrigerating and freezing apparatus, an air conditioning apparatus, or the like, in which the pressure sensor 1 is provided. A power supply voltage can be applied from the circuit to the pressure detection element 64 via the lead wire 94 and the terminal pin, and a signal for pressure detection can be output.

< assembling Process of pressure sensor >

In assembling the pressure sensor 1 shown in fig. 5, first, the relay board 90 on which the connector 92 is mounted is fixedly joined to one ends of three terminal pins protruding from the base 40 of the pressure detection unit 2.

On the other hand, the cylindrical portion 20a of the fluid inflow tube 20 is fixed to the opening 34 of the support member 30 of the pressure detection unit 2.

Next, the pressure detection unit 2 is inserted into the large diameter portion 10a of the cover 10 so that the lead 94 is inserted from the large diameter portion 10a and exposed to the outside through the small diameter portion 10 b.

Thereafter, the resin R2 is filled from the opening end on the large diameter portion 10a side and cured, and the pressure detection unit 2 is fixed in the cover 10. Similarly, the inner space S3 is closed by filling the opening of the cover 10 on the small diameter portion 10b side with resin R1 and curing the resin.

The order of filling the resins R1 and R2 may be any order.

In the pressure sensor 1 shown in fig. 5, the fluid to be pressure-detected introduced into the fluid inflow tube 20 enters the pressurizing space S2 of the pressure detection unit 2, and the diaphragm 50 is deformed by the pressure.

When the diaphragm 50 is deformed, the liquid medium in the pressure receiving space S1 is pressurized, and the pressure at which the diaphragm 50 is deformed is transmitted to the pressure detecting element 64 of the pressure detecting device 60.

The pressure detection element 64 detects the fluctuation of the transmitted pressure, converts the fluctuation into an electric signal, and outputs the electric signal to the relay substrate 90 via the terminal pin for signal output.

The electrical signal is transmitted to the wiring layer of the relay substrate 90, and is further output to an external device via the connector 92 and the lead wire 94.

According to the present embodiment, since the surfaces of the main body 41, the connection portion 43, and the flange portion 42 of the base 40 exposed to the pressure receiving space S1 and the surface of the diaphragm 50 exposed to the pressure receiving space S1 are covered with the insulating layer IS, the electrification of the liquid medium stored in the pressure receiving space S1 can be suppressed, and the occurrence of problems such as erroneous output can be avoided.

< first modification >

Fig. 6 is a cross-sectional view corresponding to fig. 5 of a first modification. In the pressure sensor 1A of the present modification, an intermediate coupling member 21 made of ceramic is provided between the support member 30 and the fluid inflow tube 20. Since the configurations other than these configurations are the same as those of the above-described embodiment, the same reference numerals are used and the description thereof is omitted.

The intermediate coupling member 21 is integrally formed of an upper cylinder 21a, a lower cylinder 21b, a flange 21c disposed between the upper cylinder 21a and the lower cylinder 21b, and a through hole 21d penetrating in the vertical direction. By forming a metallized layer (for example, a Mo — Mn layer or the like or a tungsten layer as a main component) in advance on the surface of the outer periphery of the upper cylinder 21a and the lower cylinder 21b which is in contact with the welding material, wettability of the ceramic material and the welding material can be improved. The flange portion 21c is sandwiched between the upper and lower brazed portions, and functions so as not to contact these structures. A circumferential groove may be provided to enhance this function.

The intermediate connecting member 21 and the support member 30 are joined by fitting the upper cylinder 21a into the opening 34 of the support member 30 and brazing, and the intermediate connecting member 21 and the fluid inflow pipe 20 are joined by fitting the lower cylinder 21b into the engaging portion 20c at the upper end of the fluid inflow pipe 20 and brazing. As a result, the support member 30 and the fluid inflow tube 20 can be coupled via the intermediate coupling member 21, and the through hole 21d and the through passage 20b can be in sealed communication with the pressurized space S2.

According to the present modification, since the support member 30 and the fluid inflow tube 20 are coupled via the intermediate coupling member 21 made of ceramic, which is an insulator, the electrification of the pressure detection unit 2 can be further effectively suppressed. The fluid inflow tube 20 may be a copper tube.

< second modification >

Fig. 7 is a longitudinal sectional view of a pressure detection unit 2A according to a second modification, and fig. 8 is a view of a cross section taken along line C-C in the structure of fig. 7 as viewed in the vertical direction. In the present modification, the terminal pins 70, 72, and 74 are arranged at equal intervals in the circumferential direction. This allows the terminal pins to be arranged further inside and the diameter of the seal 40c to be further increased.

In the present modification, the surface of the base 40 exposed to the pressure receiving space S1 and the surface of the diaphragm 50 exposed to the pressure receiving space S1 are also covered with the insulating layer IS (hatched not shown). Since the configurations other than these configurations are the same as those of the above-described embodiment, the same reference numerals are used and the description thereof is omitted.

< third modification >

Fig. 9 is a vertical sectional view of a pressure detecting unit 2B according to a third modification, and fig. 10 is a view showing a cross section taken along line D-D in the structure of fig. 9 as viewed in the vertical direction. This modification differs in the following points: a discharging plate 80 is formed between the base 40 and the pressure detecting device 60. The discharging plate 80 may be a metal thin plate, or a ceramic thin plate, and preferably has a metalized layer or a plated layer formed on the surface thereof.

The lower ends of the static elimination plate 80 and the grounding terminal pin 72 are soldered or soldered (F), and are electrically connected to the grounding pad 64b by a connection wire 81 (bonding wire).

In the present modification, the surface of the base 40 exposed to the pressure receiving space S1 and the surface of the diaphragm 50 exposed to the pressure receiving space S1 are also covered with the insulating layer IS (hatched not shown). Since the configurations other than these configurations are the same as those of the above-described embodiment, the same reference numerals are used and the description thereof is omitted.

The static charge suppressing effect is further improved by providing the static eliminating plate 80 connected to ground. Further, by disposing the discharging plate 80 between the base 40 and the pressure detecting device 60, an effect is also obtained in which the strain of the base 40 is less likely to be transmitted to the pressure detecting device 60.

< fourth modification >

Fig. 11 is a vertical sectional view of a pressure detecting unit 2C according to a fourth modification, and fig. 12 is a view showing a cross section taken along line E-E in the structure of fig. 11 as viewed in the vertical direction. In the present modification, the seal 40c joining the base 40 and the terminal pins 70, 72, and 74 is integrated.

The body 41 of the base 40 has an opening 41 a. The disk-shaped seal 40c holds the terminal pins 70, 72, and 74 at equal intervals in the circumferential direction, and is engaged so as to fit into the opening 41 a. Further, the seal 40c has a rectangular opening 40e in the center thereof, and a prismatic holding portion 40f made of SUS is joined to the inside of the rectangular opening 40 e. The holding portion 40f is provided with a pressure detection device 60. Further, it is preferable that the thermal expansion coefficient of the seal 40c is close to the linear expansion coefficient of the base 40 and the holding portion 40 f.

In the present modification, the surface of the base 40 exposed to the pressure receiving space S1 and the surface of the diaphragm 50 exposed to the pressure receiving space S1 are also covered with the insulating layer IS (hatched not shown). Since the configurations other than these configurations are the same as those of the above-described embodiment, the same reference numerals are used and the description thereof is omitted.

< fifth modification >

Fig. 13 is a longitudinal sectional view of a pressure detecting unit 2D according to a fifth modification, and fig. 14 is a view of a cross section taken along line G-G in the structure of fig. 13 as viewed in the vertical direction. In the above-described embodiment and modification, the base 40 is formed by pressing a flat plate, but the base 40 of the present modification is formed into a disk shape having the recess 44 on the lower surface by cold forging. This can improve the shape accuracy of the base 40.

In the present modification, the surface of the base 40 exposed to the pressure receiving space S1 and the surface of the diaphragm 50 exposed to the pressure receiving space S1 are also covered with the insulating layer IS (hatched not shown). Since the configurations other than these configurations are the same as those of the above-described embodiment, the same reference numerals are used and the description thereof is omitted.

< second embodiment >

Fig. 15 is a plan view of a pressure detection unit 100A according to a second embodiment of the present invention, and fig. 16 is a cross-section taken along line H-H in the structure of fig. 15 as viewed from the side.

As shown in fig. 15 and 16, the pressure detection unit 100A includes a base 110 made of ceramic, a support member 120 facing the base 110, a diaphragm 130 sandwiched between the base 110 and the support member 120, and a ring member 140.

The susceptor 110 includes a disk-shaped main body 111 and a projection 112 that projects annularly in the axial direction over the entire periphery of the main body 111. That is, the base 110 is formed in a shape in which the center portion of the lower surface is recessed in fig. 16 so as to form a pressure receiving space S1 described later.

A closed pressure receiving space S1 is formed between the diaphragm 130 and the lower surface 114 inside the protruding portion 112 of the base 110, and the pressure receiving space S1 is filled with an insulating liquid medium such as oil. In the present embodiment, the base 110 is made of ceramic, and has insulation properties, but has conductivity with respect to the ring member 140 and the soldering surface of the terminal pin. Therefore, these brazing surfaces exposed to the pressure receiving space S1 are covered with the insulating layer. Further, as in the above-described embodiment, the surface (entire surface) of the diaphragm 50 exposed to the pressure receiving space S1 IS also covered with the insulating layer IS (see fig. 4). This can suppress the electrification of the liquid medium. An insulating layer may be provided to the terminal pin.

Further, a pressure detection device 150 is attached to the center of the main body 111 on the pressure receiving space S1 side inside the protruding portion 112.

As shown in fig. 15, three through holes 116 into which three terminal pins 160, 162, 164 are inserted are formed in the base 110 at positions around the pressure detection device 150.

Three terminal pins 160, 162, and 164 are inserted into the through holes 116 provided in the base 110 to penetrate the base 110, and the lower ends of the terminal pins are electrically connected to the pressure detection device 150.

The support member 120 is formed of a metal material such as a stainless steel plate, for example, and is formed by press-molding into a bowl shape with a depressed central portion, and has a circular bottom portion 121, a conical portion 122 extending upward from an outer edge of the circular bottom portion 121, and a flange portion 123 extending in a horizontal direction from an outer edge of the conical portion 122.

An opening 124 for attaching a fluid inflow pipe described later is formed in the center of the circular bottom portion 121, and a diaphragm 130 is joined to the upper surface of the flange portion 123. With such a configuration, a pressurized space S2 into which a fluid to be detected flows is formed between the support member 120 and the diaphragm 130.

The pressure detection device 150 is die-bonded to the center portion of the base 110 by bonding or the like. The pressure detection device 150 includes a support substrate 152 made of glass and a pressure detection element (semiconductor chip) 154 bonded to the support substrate.

The pressure detection element 154 includes eight pads (electrodes) as shown in fig. 3. Three of the pads are a power input pad, a ground pad, and a signal output pad for outputting signals, and the remaining five are signal adjustment pads.

< Process for assembling pressure detecting Unit 100A >

The process of assembling the pressure detection unit 100A will be described below. First, the terminal pin 160 for power input, the terminal pin 162 for grounding, and the terminal pin 164 for signal output are inserted into the through hole 116 formed in the base 110, and the three terminal pins 160, 162, and 164 are fixed to the base 110 by soldering.

Specifically, solder portions are formed between the ceramic of the base 110 and the metal of the terminal pins 160, 162, and 164 by heating to a predetermined temperature in a state where a solder material such as silver solder is sandwiched between the through-hole 116 formed in the base 110 and the terminal pins 160, 162, and 164.

In this case, before the brazing operation, a metallized layer (for example, a Mo — Mn layer or the like or a tungsten layer as a main component) is formed in advance on the surface of the base 110 which is in contact with the brazing material, whereby wettability between the ceramic material and the brazing material can be improved.

Next, the base 110 is joined to the upper surface 141 of the ring member 140 by brazing. Specifically, the brazing material such as silver solder is heated to a predetermined temperature in a state of being sandwiched between the base 110 and the ring member 140, whereby the brazed portion B is formed between the ceramic material of the base 110 and the metal material of the ring member 140 over the entire circumference.

In this case, before the brazing operation, a metallized layer (for example, a Mo — Mn layer or the like or a tungsten layer as a main component) is formed in advance on the surface of the base 110 that is in contact with the brazing material, and wettability between the ceramic material and the brazing material can be improved.

Next, the pressure detection device 150 is die-bonded to the central portion of the base 110. Then, the ground pad, the power input pad, and the signal output pad of the pressure detection device 150 are electrically connected to one end of each of the three terminal pins 160, 162, and 164 via the connection wire 166.

Further, the probes for energization are brought into contact with the above-mentioned eight pads in the pressure detecting element 154 of the pressure detecting device 150 exposed into the base 110, respectively, to perform the temperature correcting operation (trimming operation) of the pressure detecting element 154.

Here, in a state where a load is applied to the pressure detection element 154 at a reference temperature (for example, room temperature), an output value output from the signal output pad or the adjustment pad is read, and a correction coefficient is set by obtaining a relationship between a predetermined pressure and an intensity value of the signal.

Finally, the diaphragm 130 is sandwiched between the support member 120 and the ring member 140, and the overlapped portion of the support member 120 and the ring member 140 is irradiated with laser light from the outer circumferential direction while the pressure receiving space S1 formed between the base 110 and the diaphragm 130 is filled with a liquid medium, and the overlapped portion is relatively rotated, and is continuously subjected to circumferential welding (W) to be integrated. Thus, the support member 120, the membrane 130, and the ring member 140 are integrated to form a pressure receiving structure.

Further, as a method of peripheral welding, welding such as arc welding or resistance welding such as seam welding can be applied without being limited to laser welding, but when reducing the strain of welding or the like, laser welding with a small heat input, electron beam welding or the like is preferably applied.

The weld W is offset from the ring member 140 and the brazed portion B of the protrusion 112 of the base 110 in a direction orthogonal to the axis O (fig. 16) of the pressure detection unit 100A, and the brazed portion B is arranged so as not to overlap the weld W when viewed in the axial direction of the pressure detection unit 100A. That is, by separating the welded portion W from the brazed portion B, the influence of heat during welding can be suppressed from affecting the brazed portion B.

< pressure sensor >

Fig. 17 is a longitudinal sectional view of the pressure sensor 1B to which the pressure detection unit 100A of the second embodiment is attached.

As shown in fig. 17, the pressure sensor 1B includes: a pressure detection unit 100A of the present embodiment illustrated in fig. 15 and 16, a cylindrical cover 10 attached to the pressure detection unit 100A, a relay board 90 to which one end of three terminal pins (only shown in fig. 160) protruding from the pressure detection unit 100A is attached, a connector 92 attached to the relay board 90, a lead wire 94 connected to the connector 92 and transmitting/receiving an electric signal and the like to/from an external device, and a fluid inflow tube 20 attached to a support member 120 of the pressure detection unit 100A.

The cover 10 is a member having a stepped cylindrical shape, and includes a large diameter portion 12 and a small diameter portion 14, and is attached to the pressure detection unit 100A from the base 110 side in a state where the large diameter portion 12 surrounds the outer peripheral portion of the pressure detection unit 100A.

As shown in fig. 17, an internal space S3 having the base 110 as a bottom surface is formed inside the cover 10, and the relay board 90 and the connector 92, which will be described later, are accommodated in the internal space S3.

The inner space S3 formed inside the cover 10 is filled with the resin R1 and cured, and the opening end side of the large diameter portion 12 is filled with the resin R2 so as to cover the pressure detection unit 100A and cured.

These resins R1 and R2 prevent moisture and the like from entering the interior of the cover 10, and protect the electrical system such as the relay board 90.

The relay substrate 90 is formed as a bakelite substrate, an epoxy glass substrate, a ceramic substrate, or a flexible substrate, one end of a connector 92 is mounted at the center thereof, and a via electrode and a metal wiring layer (not shown) are provided around the mounting position of the connector 92.

One end of the connector 92 is attached to the relay board 90, and the other end is attached to a lead 94 extending to the outside of the cover 10.

One ends of three terminal pins (only 160 shown in the drawing) protruding from the base 110 of the pressure detection unit 100A penetrate through the via electrodes of the relay substrate 90 and are fixedly bonded thereto. At this time, the three terminal pins are electrically fixed and connected to the via electrode by soldering or the like, for example.

The fluid inflow tube 20 is a tubular member made of a metal material such as a copper alloy or an aluminum alloy, and has a cylindrical portion 20A attached to the support member 120 of the pressure detection unit 100A and a through passage 20b connected to a pipe through which a fluid to be pressure-detected flows.

The cylindrical portion 20a is attached to the opening 124 of the support member 120 shown in fig. 16 by any method such as welding, adhesion, or mechanical fastening.

< assembling Process of pressure sensor >

In assembling the pressure sensor 1B shown in fig. 17, first, the relay board 90 to which the connector 92 is attached is fixedly joined to one end of three terminal pins protruding from the base 110 of the pressure detection unit 100A.

On the other hand, the cylindrical portion 20A of the fluid inflow tube 20 is fixed to the opening portion 124 of the support member 120 of the pressure detection unit 100A.

Next, the pressure detection unit 100A is inserted into the large-diameter portion 12 of the cover 10 so that the lead 94 is inserted from the large-diameter portion 12 and exposed to the outside through the small-diameter portion 14, and the upper end of the base 110 is brought into contact with the inner diameter stepped portion 13. At this time, a gap exists between the base 110 and the inner periphery of the large diameter portion 12.

Thereafter, the resin R1 is filled from the opening of the cover 10 on the small-diameter portion 14 side and cured to close the internal space S3.

Similarly, the resin R2 is filled from the opening end on the large diameter portion 12 side and cured, and the pressure detection unit 100A is fixed in the cover 10.

In the pressure sensor 1B shown in fig. 17, the fluid to be pressure-detected introduced into the fluid inflow tube 20 enters the pressurizing space S2 of the pressure detection unit 100A, and the diaphragm 130 is deformed by the pressure.

When the diaphragm 130 is deformed, the liquid medium in the pressure receiving space S1 is pressurized, and the pressure for deforming the diaphragm 130 is transmitted to the pressure detecting element 154 of the pressure detecting device 150.

The pressure detection element 154 detects the fluctuation of the transmitted pressure, converts the detected fluctuation into an electric signal, and outputs the electric signal to the relay substrate 90 via the terminal pin 164 for signal output

The electrical signal is transmitted to the wiring layer of the relay substrate 90, and is further output to an external device via the connector 92 and the lead wire 94.

With these configurations, in the pressure detection unit 100A according to the embodiment of the present invention and the pressure sensor 1B to which the pressure detection unit 100A is applied, the base 110 to which the pressure detection device 150 is attached is formed of a ceramic material having a small thermal expansion coefficient, and therefore, expansion or contraction of the base 110 due to a change in the use temperature environment of the pressure sensor 1B or the like when the pressure detection unit 100A is assembled can be suppressed.

Further, by forming the base 110 from a ceramic material having a small thermal expansion coefficient, the change in the shape and size of the base 110 is small even when exposed to a severe use environment of high temperature or low temperature, as compared with the case of forming a base from a conventional metal material, and therefore, the deterioration of the detection accuracy of the pressure detection device 150 due to a temperature environment can be suppressed.

Further, by forming the base 110 of a ceramic material, the glass seal used when embedding the terminal pin into the base in the conventional pressure detecting means can be replaced with the brazed portion.

In the pressure detection unit 100A and the pressure sensor 1 to which the pressure detection unit 100A is applied according to the embodiment of the present invention, the thin and fragile diaphragm 130 can be reinforced by the support member 120 and the ring member 140 because the pressure receiving structure in which the diaphragm 130 is integrated by being sandwiched between the support member 120 and the ring member 140 in advance is formed and the base 110 is joined to the ring member 140 of the pressure receiving structure.

< third embodiment >

Fig. 18 is a sectional view of a pressure sensor 1C using a pressure detection unit 100B according to a third embodiment. The description will be given of a portion different from the second embodiment.

The pressure detection unit 100B includes a base 110 made of ceramic, a support member 120 facing the base 110, and a diaphragm 130 and a ring member 140 sandwiched between the base 110 and the support member 120. The pressure detection unit 100B is assembled in the same manner as in the above-described embodiment.

The support member 120 of the present embodiment is an annular plate. The base 110 and ring member 140 are formed of the same material as the above-described embodiments.

The pressure detection unit 100B is coupled to the male connector 240 via the caulking holding member 250. The caulking holding member 250 has a structure in which a large hollow cylindrical portion 251, a stepped flange portion 252, and a small cylindrical portion 253 are connected in series.

In the large cylindrical portion 251, a concave portion 254 is formed at the center of the upper surface of the stepped flange portion 252, and a communication hole 255 is formed at the center thereof. The communication hole 255 passes through the inside of the small cylindrical portion 253 and is open at the lower end thereof. A circumferential groove 256 is formed around the recess 254, and an O-ring OR1 is disposed inside the groove.

The resin male connector 240 has a lower hollow cylindrical portion 241 at a lower end thereof, the resin male connector 240 further has an upper hollow cylindrical portion 242, and the relay board 90 is mounted at the center inside the lower hollow cylindrical portion 241. The three terminal pins (only fig. 160 and 162) of the pressure detection unit 100B and the relay board 90 are electrically connected by the flexible printed board 243.

The relay board 90 is electrically connected to a connector pin 244 extending from the lower hollow cylindrical portion 241 side to the inside of the upper hollow cylindrical portion 242. By fitting an unillustrated female connector to the male connector 240, a signal detected by the pressure detection unit 100B can be output to the outside via the connector pin 244.

At the time of assembly, the pressure detection unit 100B is inserted into the large cylindrical portion 251 of the caulking holding member 250, and the lower end of the lower hollow cylindrical portion 241 of the male connector 240 is brought into contact with the upper surface of the base 110. Thereafter, the upper end of the large cylindrical portion 251 is swaged inward and plastically deformed, thereby forming a swaged portion 257 and being fixed to the vicinity of the upper end of the lower hollow cylindrical portion 241 of the male connector 240. Thereby, the pressure detection unit 100B is sandwiched and held by the caulking holding member 250 and the male connector 240. However, a radial gap exists between the large cylindrical portion 251 and the base 110.

At this time, the caulking holding member 250 and the support member 120 abut against each other over the entire circumference via the O-ring OR1, thereby preventing liquid leakage.

The fluid inflow pipe 20 indicated by a one-dot chain line is a tubular member made of a metal material such as a copper alloy OR an aluminum alloy, for example, and is screwed to the outer periphery of the small cylindrical portion 253 of the caulking holding member 250, and the fluid inflow pipe 20 and the caulking holding member 250 are sealingly connected by an O-ring OR 2.

In the pressure sensor 1C shown in fig. 18, the fluid to be pressure-detected introduced into the fluid inflow tube 20 enters the pressurizing space S2 of the pressure detection unit 100B, and the diaphragm 130 is deformed by the pressure.

When the diaphragm 130 is deformed, the liquid medium in the pressure receiving space S1 is pressurized, and the pressure for deforming the diaphragm 130 is transmitted to the pressure detecting element 154 of the semiconductor-type pressure detecting device 150.

The pressure detection element 154 detects the fluctuation of the transmitted pressure, converts the detected fluctuation into an electric signal, and outputs the electric signal to the relay substrate 90 via a terminal pin (not shown) for signal output and the flexible printed board 243.

Then, the electric signal is transmitted to the wiring layer of the relay substrate 90 and is further output to an external device via the connector pin 244.

In the present embodiment, the base 110 is made of ceramic, and has insulation properties, but has conductivity with respect to the ring member 140 and the soldering surface of the terminal pin. Therefore, these solder surfaces exposed to the pressure receiving space S1 are covered with the insulating layer. Further, as in the above-described embodiment, the surface (entire surface) of the diaphragm 130 exposed to the pressure receiving space S1 IS also covered with the insulating layer IS. This can suppress the electrification of the liquid medium.

The present invention is not limited to the above-described embodiments, and various modifications can be made.