JP2013156196A - Pressure sensor, pressure gauge, and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensor which has high accuracy, high reliability, and especially high moisture resistance without pressure sensitivity changing according to the change in environmental conditions.SOLUTION: A pressure sensor 10 includes: a pressure sensitive element 40; a supporting member 30 to which the pressure sensitive element 40 is fixed; and bellows each of which has an opening part and a closing part on each end. The closing parts are bonded to the supporting member 30 by using an adhesive bond 70. The supporting member 30 has recesses into which the closing parts can be inserted at contact parts with the bellows.

Description

  The present invention relates to a pressure sensor using a bellows, and particularly to a structure of a pressure sensor excellent in moisture resistance.

  Conventionally, pressure sensors using piezoelectric vibrators as force detection elements are known as water pressure gauges, barometers, differential pressure gauges, and the like. In the piezoelectric vibrator, for example, an electrode pattern is formed on a plate-like piezoelectric substrate, and a detection axis is set in the force detection direction. When pressure is applied in the direction of the detection axis, the resonance frequency of the piezoelectric vibrator is reduced. The pressure is detected from the change of the resonance frequency.

  9A and 9B are explanatory diagrams of a conventional pressure sensor, in which FIG. 9A is a schematic diagram of the configuration, FIG. 9B is a cross-sectional side view of an enlarged pair of bellows, and FIG. 9C is a side view showing an adhesion state between the bellows and the support member. FIG. As shown in FIG. 9A, a conventional pressure sensor 100 includes a pressure sensitive element 103, a cantilever 104, a first bellows 105, and a second bellows 106 that serve as a force transmission means in a casing 102. Is kept airtight. In the pressure sensor 100, the opening ports of the first bellows 105 and the second bellows 106 are fixed to two pressure introduction ports 107a and 107b formed to face the side wall of the casing 102, respectively. The pressure receiving surfaces 104 c and 104 d of the flexible portion 104 a of the cantilever 104 are fixed between the pressure receiving portions 105 a and 106 a of the first bellows 105 and the second bellows 106. On the other hand, the fixing portion 104b formed through the flexible portion 104a and the fulcrum 108 of the cantilever 104 is fixed to the casing 102, and the pressure-sensitive element 103 is bonded and fixed between the flexible portion 104a and the fixing portion 104b. .

  In the pressure sensor 100 having the above configuration, when pressure is first applied to the bellows from the pressure introduction ports 107a and 107b, the pressure according to the effective area of the pressure receiving portion of the bellows is subjected to pressure receiving surfaces 104c and 104d of the flexible portion 104a of the cantilever 104. It takes. A force corresponding to the pressure differential pressure is applied as a compressive force or a tensile force to the pressure sensitive element 103 via the fulcrum 108, and the resonance frequency of the pressure sensitive element 103 changes according to this force. The pressure is measured by detecting this change.

Patent Documents 1 and 2 disclose the above-described bellows and a pressure sensor using a piezoelectric vibration element as a pressure-sensitive element.
In Patent Document 3, the above-described pressure sensor is provided in the case of the pressure gauge. Two detectors are connected to the pressure gauge, one provided at the tip of the case and the other provided at the side of the case. Then, the case is disposed in the fluid, and one of the detection portions is oriented in substantially the same direction as the flow direction in the fluid so that static pressure and dynamic pressure are applied. Further, the other detection unit is directed in a direction substantially orthogonal to the flow direction so that only the static pressure is applied.

JP-A-2-228534 Japanese Patent Laid-Open No. 56-119519 JP-A-6-66656

  The pressure sensor of the differential pressure structure is arranged on the coaxial line with the pressure receiving portions of the two bellows facing each other in order to increase the pressure receiving sensitivity. For this reason, as shown in FIG. 9B, the conventional pressure sensor has convex protrusions 110 and 112 at the centers of the pressure receiving portion end surfaces of the two bellows. The protrusions 110 and 112 are composed of a male structure (110) with the tip closed and a female structure (112) with the tip open, and are configured to be able to fit together. When fixing the bellows (105, 106) to the casing 102, first, an epoxy resin adhesive 114 is applied to the protrusion 110 and the pressure receiving portion 105a of the first bellows 105 having a male structure. Next, as shown in FIG. 9C, the first bellows 105 having a male structure is inserted into the through hole 116 formed in the pressure receiving surface of the cantilever 104. Further, the second bellows 106 having a female structure in which the adhesive 114 is applied to the pressure receiving portion 106 a is inserted into the through hole 116, and the first bellows 105 having the male structure and the second bellows having the female structure are inserted into the through hole 116. A bellows 106 is fitted and bonded. After that, the adhesive 114 is filled through the adhesive filling hole 118 orthogonal to the through hole 116, and the adhesive 114 is filled into the gap between the through hole 114 and the bellows (105, 106) and bonded and fixed. Yes.

  As described above, air, water, and the like are introduced into the bellows of a pressure sensor such as a water pressure gauge, a barometer, and a differential pressure gauge. In particular, in the case of a hydraulic pressure sensor, air or moisture containing water vapor may enter from the inside of a female bellows tube. Under such environmental conditions, the epoxy adhesive between the bellows of the male structure and the female structure expands or contracts by absorbing or discharging moisture.

  As a result, when the adhesive expands or contracts, the volume of the adhesive fluctuates, and local internal stress is generated at the connection portion (fixed portion) between the bellows and the cantilever. In this way, a stress change occurs according to the environmental conditions, which adversely affects the pressure receiving sensitivity of the pressure sensor. As a result, there has been a problem that the resonance frequency of the vibrator, which is a pressure-sensitive element, fluctuates due to factors other than pressure, resulting in measurement value errors.

  An object of the present invention is to solve the above-described problems, and realizes a highly accurate and reliable pressure sensor having high humidity resistance, in which pressure receiving sensitivity does not vary due to changes in environmental conditions. For the purpose.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.
[Application Example 1] A pressure-sensitive element, a support member to which the pressure-sensitive element is fixed, a bellows having an opening provided at one end and closed at the other end, and the other end being an adhesive. A pressure sensor, wherein the pressure sensor is adhered to the support member.
With the above configuration, since the pressure receiving portion side of the bellows is closed in a bag hole shape, the adhesive between the bellows and the support member is kept airtight in the container, and air introduced into the inside through the shaft hole of the bellows, Never touch. Accordingly, the adhesive does not expand or contract due to humidity such as the atmosphere, and the pressure receiving sensitivity of the pressure sensitive element does not fluctuate, and a highly accurate and highly moisture-resistant pressure sensor can be realized.

[Application Example 2] The pressure sensor according to Application Example 1, wherein the support member is provided with a concave portion into which the other end can be inserted at a contact portion of the bellows.
With the above configuration, it is possible to easily and accurately position the adhesion portion between the pressure receiving portion of the bellows and the support member, and it is possible to realize a highly accurate pressure sensor.

Application Example 3 A pressure-sensitive element, a support member to which the pressure-sensitive element is fixed, a first bellows in which an opening is provided at one end and the other end is closed, and an opening is provided in one end A second bellows whose other end is closed, and each of the first bellows and the second bellows is provided with a protrusion projecting from the other end toward the support member, and the protrusion is provided at both ends. The protrusions are respectively inserted into connecting members having the insertion portions, and the first bellows and the second bellows are coaxially disposed along the displacement direction of the bellows. pressure sensor.
With the above-described configuration, it is possible to easily and accurately position the adhesion portion between the pressure receiving portion of the bellows and the support member. Further, the axial center of the first bellows and the second bellows can be coaxially arranged by the connecting member along the displacement direction of the bellows, and a pressure sensor with higher accuracy than the configuration of the application example 1 can be realized. Can do.

Application Example 4 A pressure-sensitive element, a support member to which the pressure-sensitive element is fixed, a first bellows in which an opening is provided at one end and the other end is closed, and an opening is provided in one end The second bellows whose other end is closed, and the first bellows and the second bellows are each provided with a protrusion protruding from the bottom toward the opening, and the insertion portions of the protrusions at both ends. The pressure sensor is characterized in that the protrusions are respectively inserted into the connecting members provided with the first bellows and the second bellows being coaxially disposed along the displacement direction of the bellows.
With the above-described configuration, it is possible to easily and accurately position the adhesion portion between the pressure receiving portion of the bellows and the support member. Further, the axial center of the first bellows and the second bellows can be coaxially arranged by the connecting member along the displacement direction of the bellows, and a pressure sensor with higher accuracy than the configuration of the application example 1 can be realized. Can do.

Application Example 5 A pressure sensor according to any one of Application Examples 1 to 4, further comprising a circuit for driving the pressure sensitive element.
With the above configuration, a pressure sensor that vibrates at a specific resonance frequency can be obtained.

[Application Example 6] A pressure gauge comprising the pressure sensor according to any one of Application Examples 1 to 5.
The above configuration realizes a pressure gauge equipped with a highly accurate and highly moisture-resistant pressure sensor without causing expansion or contraction of the adhesive due to humidity such as the atmosphere, without changing the pressure sensitivity of the pressure sensitive element. be able to.

Application Example 7 An electronic device comprising the pressure sensor according to any one of Application Examples 1 to 5.
With the above configuration, an electronic device including a pressure sensor with high accuracy and high humidity resistance is realized without causing expansion or contraction of the adhesive due to humidity such as the atmosphere, and pressure sensitivity of the pressure sensitive element does not fluctuate. be able to.

It is explanatory drawing of the pressure sensor of 1st Embodiment, (a) is a structure schematic, (b) has shown the side view which expanded some bellows and a supporting member. It is a graph which shows the relationship between the humidity of a pressure sensor, and the change rate ((DELTA) f) of an oscillation frequency. It is explanatory drawing of the pressure sensor of 2nd Embodiment, (a) is a structure schematic, (b) has shown sectional drawing of the side surface to which some bellows and the supporting member were expanded. It is explanatory drawing of the pressure sensor of 3rd Embodiment, (a) is a structure schematic, (b) has shown sectional drawing of the side which expanded the bellows and a part of supporting member. It is explanatory drawing of the pressure sensor of 4th Embodiment, (a) is the structure schematic of the adhesion part of a bellows and a supporting member, (b) shows sectional drawing of the side which expanded a part of bellows and a supporting member. Yes. It is explanatory drawing of the pressure sensor of 5th Embodiment, (a) is the structure schematic of the adhesion part of a bellows and a supporting member, (b) shows sectional drawing of the side which expanded a part of bellows and a supporting member. Yes. It is a block schematic diagram of the pressure sensor of a 6th embodiment. It is a structure schematic of the pressure sensor of 7th Embodiment. It is explanatory drawing of the conventional pressure sensor, (a) is a structure schematic, (b) is sectional drawing of the side which expanded a pair of bellows, (c) is sectional drawing of the side showing the adhesion state of a bellows and a supporting member. Is shown.

Embodiments of the pressure sensor of the present invention will be described in detail below with reference to the accompanying drawings.
1A and 1B are explanatory views of a pressure sensor according to the first embodiment. FIG. 1A is a schematic configuration diagram, and FIG. 1B is a side view in which a part of a bellows and a support member 30 is enlarged. As shown in the figure, the pressure sensor 10 of the present invention includes a container 20 in which pressure inlets (first inlet 22 and second inlet 24) are formed on a wall surface, a shaft hole connected to the inlet, A cylindrical bellows having a pressure receiving portion, a support member 30 that supports the pressure receiving portion, an adhesive 70 that bonds the pressure receiving portion and the support member 30, and a first base at both ends of the pressure sensing portion 46 42 and a second base 44 are disposed, the first base 42 is fixed to the container 20, and the pressure sensitive element 40 is fixed to the support member 30. .

  The container 20 is a casing that can accommodate a bellows, a support member 30, and a pressure sensitive element, which will be described later. The container 20 has a pair of pressure inlets (first inlet 22 and second inlet 24) formed on opposing wall surfaces. The container 20 is hermetically maintained such as a vacuum or an inert atmosphere in the internal space. As an example of the material of the container 20, stainless steel having a small thermal expansion coefficient can be used.

  The support member 30 of the first embodiment is a cantilever as illustrated. The cantilever connects the fixed portion 32 and the flexible portion 34 via a constricted portion 36. The fixing portion 32 is a base portion having an L-shaped cross section, and has one end connected to the flexible portion 34 and the other end fixed to the container 20. In this embodiment, the other end is fixed to the wall surface of the container 20 as an example. The flexible portion 34 is a support piece connected to the fixed portion 32 near the center. A thin constricted portion 36 serving as a fulcrum is formed at a connection portion between the flexible portion 34 and the fixed portion 32. The flexible portion 34 is configured to be swingable with the constricted portion 36 as a fulcrum. The flexible portion 34 includes a first pressure receiving surface 35a and a second pressure receiving surface 35b that come into contact with pressure receiving portions 52 and 62 of a first bellows 50 and a second bellows 60 described later. For example, the support member 30 may be made of stainless steel, phosphor bronze, or the like.

The bellows is a cylindrical member, and has a shaft hole serving as an opening at one end and a pressure receiving portion at the other end. The bellows is formed in a bag hole shape from the shaft hole toward the pressure receiving portion, closes the pressure receiving portion side, and isolates the inside and the outside of the pressure receiving portion. The bellows of the first embodiment includes a first bellows 50 and a second bellows 60, and includes shaft holes 51 and 61 connected to a pressure inlet at one end and a large hole introduced from the shaft holes 51 and 61 at the other end. Pressure receiving portions 52 and 62 for receiving pressure such as atmospheric pressure or water pressure are formed. The shaft hole 51 of the first bellows 50 is fixed to the first introduction port 22 of the container 20. The outer wall of the pressure receiving portion 52 of the first bellows 50 is bonded and fixed to the first pressure receiving surface 35 a of the flexible portion 34. Further, the outer wall of the pressure receiving portion 62 of the second bellows 60 is bonded and fixed to the second pressure receiving surface 35 b of the flexible portion 34. As an example of the material of the bellows, nickel or phosphor bronze can be used.
The adhesive 70 that bonds the pressure receiving surfaces (the first pressure receiving surface 35a and the second pressure receiving surface 35b) of the support member 30 and the pressure receiving portions 52 and 62 of the bellows uses an adhesive containing an epoxy resin.

  The pressure-sensitive element 40 of the first embodiment is formed as a double tuning fork type piezoelectric vibrator using a piezoelectric material such as quartz, lithium niobate, lithium tantalate or the like. The pressure sensitive element 40 is supported by connecting the first base portion 42 and the second base portion 44 of the pressure sensitive element 40 to the fixed portion 32 and the flexible portion 34 of the support member 30. At this time, the pressure-sensitive element 40 sets the detection direction of force as a detection axis, and the direction connecting the first base portion 42 and the second base portion 44 of the pressure-sensitive element 40 is parallel to the detection axis. The pressure sensitive element 40 is electrically connected to a drive circuit (not shown) attached to the container 20 and vibrates at an inherent resonance frequency by an AC voltage from the oscillation circuit. The pressure frequency of the pressure-sensitive element 40 varies due to the elongation (tensile) stress or the compressive stress from the support member 30. In particular, the double tuning fork type piezoelectric resonator element has a very large change in resonance frequency with respect to elongation / compression stress and a wide variable range of resonance frequency compared to a thickness shear vibrator, etc., so it can be decomposed to detect a slight pressure difference. It is suitable for a pressure sensor that excels in resistance. When the double tuning fork type piezoelectric vibrator is subjected to an extension stress, the amplitude width of the vibrating arm (vibrating part) is reduced, so that the resonance frequency is increased. When the compressive stress is applied, the amplitude width of the vibrating arm (vibrating part) is increased. The resonance frequency is lowered. As the piezoelectric substrate of the double tuning fork type piezoelectric vibrator, quartz having excellent temperature characteristics is desirable.

  The vibration part as the pressure-sensitive part 46 of the pressure-sensitive element 40 is described using the case of a double tuning fork type piezoelectric vibrator (consisting of two vibration beams). The vibration beam may be configured. That is, as the piezoelectric vibrator, a single beam type or a three tuning fork type vibrator can be used.

  In addition, the vibration part as the pressure-sensitive part 46 of the pressure-sensitive element 40 is not limited to the vibrator constituted by the vibration beam, but any piezoelectric vibrator whose resonance frequency is changed by extension / compression stress can be used. For example, a thickness shear vibrator, a SAW resonator, or the like can be used.

  If an AT-cut quartz crystal unit with the thickness-shear mode as the main vibration is used for the vibration part, the frequency-temperature characteristic becomes a cubic curve, which is a frequency-temperature characteristic compared to a tuning-fork type oscillator with a convex quadratic curve. It is possible to realize an excellent pressure sensor.

  In addition, when a SAW resonator is used for the vibration part, a comb-shaped electrode that serves as an excitation electrode, that is, a so-called IDT (interdigital transducer) may be formed only on one main surface of a piezoelectric substrate such as crystal. Cost reduction can be expected.

  As shown in FIG. 1B, the pressure sensor 10 having the above configuration applies an adhesive 70 to the outer walls of the pressure receiving portions 52 and 62 closed in a bag hole shape of the first bellows 50 and the second bellows 60. The support member 30 is bonded to the first pressure receiving surface 35a and the second pressure receiving surface 35b.

  In the pressure sensor 10 of the first embodiment, when pressure is applied to the first bellows 50 and the second bellows 60 from the two pressure inlets, a force corresponding to the effective area of the bellows acts on both main surfaces of the support member 30. To do. A force corresponding to the differential pressure is applied to the pressure-sensitive element 40 as a compressive force or a tensile force with the constricted portion 36 as a fulcrum. The resonance frequency of the pressure sensitive element 40 changes according to this force. The pressure can be measured based on the change in the resonance frequency. When either the first bellows 50 or the second bellows 60 is closed and the internal pressure is maintained at a predetermined value, the absolute pressure can be measured. In the pressure sensor 10 of the first embodiment, the sealed space of the container 20 is kept airtight such as an atmosphere in a vacuum or an inert atmosphere, and the bellows is closed in a bag hole shape from the shaft hole toward the pressure receiving portion. . For this reason, an adhesive agent does not touch the air etc. which were introduced from the shaft hole.

  FIG. 2 is a graph showing the relationship between the humidity of the pressure sensor and the change rate (Δf) of the oscillation frequency. The horizontal axis of the graph represents time (h), and the vertical axis represents the change rate (Δf) of the oscillation frequency. The ◯, Δ, and □ plots are the pressure sensors 10 (three products) of the present embodiment, and the ●, ▲, and ■ plots are the conventional pressure sensors (three products) shown in FIG. First, the change rate of the oscillation frequency of the pressure sensor is stabilized until time A in an environment of room temperature (about 25 ° C.) and normal humidity. When the dehumidification is performed after the elapse of time A, the pressure sensor 10 of the present embodiment does not change with the change rate Δf of the oscillation frequency being 0. This is because the adhesive between the bellows and the support member is not affected by humidity. On the other hand, the conventional pressure sensor contracts due to the moisture exudation of the adhesive on the bellows protrusion, and local internal stress is generated at the connection part of the bellows and the support member, and the rate of change of the oscillation frequency is either ±. Has also changed. And once it returns to normal humidity, the rate of change of the oscillation frequency becomes constant again (time B), and when it is humidified, the rate of change of the oscillation frequency of the pressure sensor 10 of this embodiment remains constant. On the other hand, the conventional pressure sensor expands due to moisture absorption by the adhesive on the bellows protrusion, and a local internal stress is generated at the connection between the bellows and the support member. In this case, the rate of change of the previous dehumidification and oscillation frequency changes to ± which is reversed.

  According to such a pressure sensor of the present invention, since the pressure receiving portion side of the bellows is closed in a bag hole shape, the adhesive between the bellows and the support member is kept airtight in the container, and the shaft hole of the bellows There is no contact with the air or the like introduced from the inside. Accordingly, the adhesive does not expand or contract due to humidity such as the atmosphere, and the pressure receiving sensitivity of the pressure sensitive element does not fluctuate, and a highly accurate and highly moisture-resistant pressure sensor can be realized.

  3A and 3B are explanatory views of a pressure sensor according to the second embodiment. FIG. 3A is a schematic configuration diagram, and FIG. In the pressure sensor 10A of the second embodiment, concave portions 80a and 80b are formed in which bellow pressure receiving portions 52 and 62 are inserted and fitted into the support member 30A. Other configurations are the same as those of the pressure sensor 10 of the first embodiment. The support member 30A has recesses 80a and 80b formed on one or / and the other main surface that adhere to the pressure receiving portions 52 and 62 of the bellows. Specifically, in the pressure sensor 10A of the second embodiment, the pressure receiving portions 52 and 62 of the first and second bellows 50 and 60 are inserted into the concave portions 80a and 80b on one main surface and the other main surface of the support member 30A. Thus, the first bellows 50 and the second bellows 60 are formed coaxially along the displacement direction of the bellows when fitted. In addition, the 1st bellows 50 and the 2nd bellows 60 are formed in the bag hole shape which protruded toward the pressure receiving parts 52 and 62 from the shaft holes 51 and 61 like the bellows of a 1st embodiment, and the pressure receiving part side is formed. It is configured to block. The pressure sensor 10 </ b> A according to the second embodiment having the above-described configuration applies the adhesive 70 to the adhesion surfaces of the pressure receiving portions 52 and 62 of the first bellows 50 and the second bellows 60 with the support member 30 </ b> A. Then, the pressure receiving portions 52 and 62 of the first bellows 50 and the second bellows 60 are inserted into the concave portions 80a and 80b on one and the other main surfaces of the support member 30A and fixed on the axis.

  According to such a pressure sensor of the second embodiment, the adhesive between the bellows and the support member does not come into contact with the air introduced from the shaft hole, and the pressure receiving sensitivity of the pressure sensitive element varies due to the influence of humidity. There is nothing. Therefore, a pressure sensor with high accuracy and high moisture resistance can be realized. Further, the concave portion can easily and accurately position the pressure receiving portion of the bellows to be bonded to the support member, and a highly accurate pressure sensor can be realized.

  4A and 4B are explanatory views of a pressure sensor according to a third embodiment. FIG. 4A is a schematic configuration diagram, and FIG. In the pressure sensor 10B of the third embodiment, protrusions 82a and 82b are formed in the pressure receiving part of the bellows, and the protrusions 84a and 82b are inserted into and fitted into the connection portions of the support member 30B that contacts the pressure receiving part 84a. , 84b are formed. Other configurations are the same as those of the pressure sensor 10 of the first embodiment. The protrusions 82a and 82b of the pressure receiving portion of the bellows are formed in a convex shape protruding from the shaft hole toward the support member 30B. The concave portions 84a and 84b of the support member 30B are formed in a concave shape in the thickness direction from the main surface side at a location where the pressure receiving portion of the bellows contacts. Specifically, in the pressure sensor 10B of the second embodiment, the protrusions 82a and 82b of the first bellows 50B and the second bellows 60B are inserted into the recesses 84a and 84b on one main surface and the other main surface of the support member 30B. The first bellows 50B and the second bellows 60B are formed coaxially along the bellows displacement direction. The first bellows 50B and the second bellows 60B are formed with protrusions 82a and 82b on the contact surface side from the pressure receiving portion to the support member 30B. The protrusions 82a and 82b are the same as the bellows of the first embodiment. The bag is formed in a bag hole shape projecting from the shaft hole toward the pressure receiving portion, and the pressure receiving portion side is closed. The pressure sensor 10B of the third embodiment having the above configuration applies the adhesive 70 to the protrusions 82a and 82b of the first bellows 50 and the second bellows 60. And protrusion 82a, 82b of the 1st bellows 50 and the 2nd bellows 60 is inserted in crevice 84a, 84b of one main surface of support member 30B, and the other, and it fixes on an axis.

  According to such a pressure sensor of the third embodiment, the adhesive between the bellows and the support member does not come into contact with the air introduced from the shaft hole, and the pressure receiving sensitivity of the pressure sensitive element varies due to the influence of humidity. Therefore, a pressure sensor with high accuracy and high moisture resistance can be realized. Further, the concave portion can easily and accurately position the pressure receiving portion of the bellows to be bonded to the support member, and a highly accurate pressure sensor can be realized.

  5A and 5B are explanatory views of a pressure sensor according to a fourth embodiment, wherein FIG. 5A is a schematic diagram of a bonding portion between a bellows and a support member, and FIG. 5B is a cross-sectional side view of an enlarged part of the bellows and the support member. Is shown. The bellows of the pressure sensor 10C according to the fourth embodiment is formed with protrusions 86a and 86b at the contact portions between the pressure receiving portions 52C and 62C and the support member 30C, similarly to the first bellows 50B and the second bellows 60B according to the third embodiment. However, similar to the bellows of the first embodiment, the projections 86a and 86b are formed in a bag hole shape protruding from the shaft holes 51 and 61 toward the pressure receiving portions 52C and 62C to close the pressure receiving portion side. It is configured as follows. And the cylindrical connection member 88 provided with the insertion parts 88a and 88b which can insert protrusion 86a, 86b of the 1st bellows 50C and the 2nd bellows 60C is used. The connecting member 88 is a pipe in which the insertion portions 88a and 88b are set to have a diameter slightly larger than the diameter of the bellows projections 86a and 86b, and the projections 86a and 86b can be inserted from the openings (insertions 88a and 88b) at both ends. It is. Further, the support member 30C is formed with a through-hole 90 into which the connecting member 88 can be inserted at a position where it comes into contact with the pressure receiving portions 52C and 62C of the bellows. In the pressure sensor 10C according to the fourth embodiment having the above-described configuration, the connecting member 88 is inserted into the through hole 90 of the support member 30C. And the adhesive agent 70 is apply | coated to the outer wall of the pressure receiving parts 52C and 62C of the 1st bellows 50C and the 2nd bellows 60C. The protrusions 86a and 86b of the first bellows 50C and the second bellows 60C are inserted into the through holes 90 on one main surface and the other main surface of the support member 30C, respectively, and coaxially along the displacement direction of the bellows. Fix it.

  According to such a pressure sensor of the fourth embodiment, the adhesive between the bellows and the support member does not come into contact with the atmosphere introduced from the shaft hole, and the pressure receiving sensitivity of the pressure sensitive element varies due to the influence of humidity. Therefore, a pressure sensor with high accuracy and high moisture resistance can be realized. In addition, the connecting member can easily and accurately position the pressure receiving portion of the bellows to be bonded to the support member, and a highly accurate pressure sensor can be realized.

  6A and 6B are explanatory views of a pressure sensor according to a fifth embodiment, in which FIG. 6A is a schematic configuration diagram of a bonding portion between a bellows and a support member, and FIG. 6B is a side sectional view of a part of a pair of bellows enlarged. Show. In the bellows of the pressure sensor 10D of the fifth embodiment, concave portions 92a and 92b are formed at contact portions between the pressure receiving portions 52D and 62D and the support member 30D. The recesses 92a and 92b are in the form of bag holes protruding from the pressure receiving portions 52D and 62D toward the shaft holes 51 and 61 (projections protruding from the pressure receiving portion serving as the bottom to the shaft hole serving as the opening as viewed from the shaft hole side. And the pressure receiving portions 52D and 62D are closed. A cylindrical connecting member 88A that can be inserted into the recesses 92a and 92b of the first bellows 50D and the second bellows 60D is used. The connecting member 88A is a member that can be inserted into the recesses 92a and 92b with both ends set to a diameter slightly smaller than the diameter of the recesses 92a and 92b of the bellows. The connecting member 88A may be a cylindrical pipe having both ends open as long as both ends can be inserted into the recesses 92a and 92b. Further, the support member 30D is formed with a through-hole 90A into which the connecting member 88A can be inserted at a position where it comes into contact with the pressure receiving portions 52D and 62D of the bellows. The thickness of the support member 30D is set to be shorter than the connecting member 88D (length in the long side direction) so that the end of the connecting member 88A protrudes from the opening of the through hole 90A. Pressure sensor 10D of 5th Embodiment by the said structure inserts a connection member in the through-hole of support member 30D. Then, an adhesive is applied to the outer surfaces (including the concave portions 92a and 92b) of the pressure receiving portions 52D and 62D of the first bellows 50D and the second bellows 60D. The concave portions 92a and 92b of the first bellows 50D and the second bellows 60D are inserted into both ends of the connecting member 88A, and the pressure receiving portions 52D and 62D are bonded to one main surface and the other main surface of the support member 30D, It is fixed on the same axis along the displacement direction of the bellows.

  According to the pressure sensor of the fifth embodiment, the adhesive between the bellows and the support member does not come into contact with the air introduced from the shaft hole, and the pressure receiving sensitivity of the pressure sensitive element varies due to the influence of humidity. Therefore, a pressure sensor with high accuracy and high moisture resistance can be realized. In addition, the connecting member can easily and accurately position the pressure receiving portion of the bellows to be bonded to the support member, and a highly accurate pressure sensor can be realized.

FIG. 7 is a schematic configuration diagram of a pressure sensor according to the sixth embodiment. The pressure sensor 10E of the sixth embodiment is a sensor in which a shaft hole 95 of a bellows 94 is attached to one pressure introduction port 93 formed in the container 20E. Other configurations are the same as those of the pressure sensor 10 of the first embodiment. As shown in the drawing, the pressure sensor 10E of the sixth embodiment is similar to the bellows of the first embodiment. It is made to adhere to one main surface. The pressure sensor 10E according to the sixth embodiment having such a configuration can measure the absolute pressure by operating the inside of the container 20 in a vacuum or in an inert atmosphere. In addition, the adhesive between the bellows 94 and the support member 30 does not come into contact with the air introduced from the shaft hole 95, and the pressure receiving sensitivity of the pressure sensitive element 40 does not fluctuate due to the influence of humidity. A highly sensitive pressure sensor can be realized.
In addition, the pressure sensor 10E of 6th Embodiment is good also as a structure which applies the protrusion of the bellows of 2nd-3rd Embodiment, and the recessed part of a supporting member.

  FIG. 8 is a schematic configuration diagram of a pressure sensor according to the seventh embodiment. Although the above-described support member 30 has been described with a cantilever configuration, it may have a partition plate configuration as shown in FIG. In the pressure sensor 10F of the seventh embodiment, a case 202 formed of a cylindrical outer wall surface 204 and a cylindrical inner wall surface arranged inside the outer wall surface 204 forms the entire outer shape. The wall surface is a bellows 206 that can expand and contract in the longitudinal direction of the cylinder. Further, an internal space 222 is formed between the outer wall surface 204 and the bellows 206, and a vacuum or an inert atmosphere is formed.

  The bellows 206 is partitioned by a partition plate 212 at the center in the longitudinal direction (stretching direction), and the bellows 206 is divided into a first bellows 208 and a second bellows 210. In the first bellows 208 and the second bellows 210, the pressure receiving portion is bonded to the bonding portion of the partition plate 212 via an adhesive. Pressure inlets 214 and 216 are respectively formed at both ends of the case 202, the pressure inlet 214 is connected to the first bellows 208, and the pressure inlet 216 is connected to the second bellows 210.

  Thus, in the case 202, the pressure introduction port 214 is an opening, the first bellows 208, a pressure introduction space 218 having one main surface of the partition plate 212 as an inner wall, and the pressure introduction port 216 are openings. The second bellows 210 and the pressure introduction space 220 having the other main surface of the partition plate 212 as the inner wall are formed. In the above configuration, when pressure is applied to the pressure introduction spaces 218 and 220, the partition plate 212 is displaced toward the pressure introduction space where the pressure is low.

  On the other hand, a piezoelectric vibrator 224 is disposed in an internal space 222 between the outer wall surface 204 and the bellows 206. The piezoelectric vibrator 224 is disposed at a position facing the second bellows 210 and is oriented so that its longitudinal direction is parallel to the displacement direction of the partition plate 212. The longitudinal direction of the piezoelectric vibrator 224 serves as a force detection axis of the piezoelectric vibrator 224. One end of the piezoelectric vibrator 224 in the longitudinal direction is connected to the partition plate 212, and the other end is connected to the case 202. The piezoelectric vibrator 224 has a configuration in which electrodes are formed on a quartz substrate, for example. On the other hand, a gap 204 a formed on the outer wall surface 204 of the case 202 is provided with a drive circuit 228 that is electrically connected to the electrode of the piezoelectric vibrator 224 and oscillates the piezoelectric vibrator 224. Therefore, the piezoelectric vibrator 224 oscillates at a predetermined resonance frequency when an AC voltage is applied from the drive circuit 228.

  A piezoelectric reinforcing plate 226 made of the same material as the piezoelectric vibrator 224 is disposed on the opposite side of the piezoelectric vibrator 224 across the second bellows 210. The piezoelectric reinforcing plate 226 has a longitudinal direction in a direction parallel to the piezoelectric vibrator 224, one end in the longitudinal direction is connected to the partition plate 212, and the other end is connected to the second bellows 210 side of the case 202.

  Further, a reinforcing leaf spring 230 is connected between the end face of the partition plate 212, the case 202, and the outer wall surface 204, so that durability against an impact from a direction other than the displacement direction of the partition plate 212 of the pressure sensor 200 can be enhanced. it can.

With the above configuration, the piezoelectric vibrator 224 receives tensile stress when the partition plate 212 is displaced toward the first bellows 208 side, and receives compressive stress when the partition plate 212 is displaced toward the second bellows 210 side.
In addition, the pressure sensor of 7th Embodiment is good also as a structure which applies the bellows and connection member of 2nd-5th Embodiment.

Such a pressure sensor of this embodiment can be used as a pressure gauge, for example.
Examples of the electronic device include general industrial measuring devices, electronic blood pressure monitors, electronic devices with altitude / atmospheric pressure / water depth measuring function, portable devices, automobiles, and the like.

10, 10A, 10B, 10C, 10D, 10E, 10F ......... pressure sensor, 20, 20E ......... container, 22 ......... first inlet, 24 ......... second inlet, 30, 30A ... ... support member, 32 ... fixed part, 34 ... flexible part, 35a ... first pressure receiving surface, 35b ... second pressure receiving surface, 36 ... constricted part, 40 ... pressure sensitive Element, 42 ......... First base, 44 ......... Second base, 46 ......... Pressure sensitive part, 50 ......... First bellows, 51 ......... Shaft hole, 52 ......... Pressure receiving part, 60 ... 2nd bellows 61 ... Shaft hole 62 ... Pressure receiving portion 70 ... Adhesive 80a, 80b Recess, 82a 82b Projection 84a 84b Recess 86a, 86b ......... Protrusions, 88,88A ......... Connecting members, 90,90A ......... Through holes, 92a, 92b ......... Recesses 93 ......... Introduction port, 94 ......... Bellows, 95 ......... Shaft hole, 96 ......... Pressure receiving part, 100 ......... Pressure sensor, 102 ......... Case, 103 ......... Pressure sensitive element, 104 ... ...... Cantilever, 104a ......... Flexible part, 104b ......... Fixed part, 105 ......... First bellows, 105a ......... Pressure receiving part, 106 ......... Second bellows, 106a ......... Pressure receiving part, 107a 107b ......... pressure inlet 108 ......... fulcrum 110, 112 ... projection 114 ... adhesive 116 ... through hole 118 ... filling hole 200 ... pressure Sensor, 202 ......... Case, 204 ......... Outer wall surface, 204a ......... Gap, 206 ......... Bellows, 208 ......... First bellows, 210 ......... Second bellows, 212 ......... Partition Plate, 214 ......... Pressure inlet, 2 6... Pressure introducing port 218... Pressure introducing space 220... Pressure introducing space 222 222 Internal space 224 Piezoelectric vibrator 226 Piezoelectric reinforcing plate 228 ... Drive circuit, 230 ... Reinforcing leaf spring.

Claims (7)

A pressure sensitive element;
A support member to which the pressure sensitive element is fixed;
A bellows provided with an opening at one end and closed at the other end;
With
The pressure sensor, wherein the other end is bonded to the support member using an adhesive. In claim 1,
The support member is
A pressure sensor, characterized in that a recessed portion into which the other end can be inserted is provided at a contact location of the bellows. A pressure sensitive element;
A support member to which the pressure sensitive element is fixed;
A first bellows provided with an opening at one end and closed at the other end;
A second bellows provided with an opening at one end and closed at the other end;
With
Each of the first bellows and the second bellows is provided with a protrusion protruding from the other end toward the support member,
Each of the protrusions is inserted into a connecting member having insertion portions of the protrusions at both ends,
The pressure sensor, wherein the first bellows and the second bellows are arranged coaxially along a displacement direction of the bellows. A pressure sensitive element;
A support member to which the pressure sensitive element is fixed;
A first bellows provided with an opening at one end and closed at the other end;
A second bellows provided with an opening at one end and closed at the other end;
The first bellows and the second bellows are respectively
Protrusions protruding from the bottom toward the opening are provided,
Each of the protrusions is inserted into a connecting member having insertion portions of the protrusions at both ends,
The pressure sensor, wherein the first bellows and the second bellows are arranged coaxially along a displacement direction of the bellows. In any one of Claims 1 thru | or 4,
A circuit for driving the pressure sensitive element;
A pressure sensor characterized by comprising:   A pressure gauge comprising the pressure sensor according to any one of claims 1 to 5.   An electronic apparatus comprising the pressure sensor according to any one of claims 1 to 5.