JP2012093196A - Pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure sensor which can highly accurately detect pressure and which has high resistance to the impact in a direction orthogonal to the surface direction of a piezoelectric vibration element.SOLUTION: The pressure sensor includes: a diaphragm 28 having a center part 30 being displaced in a pressure-receiving direction, and a peripheral part 34 positioned on the outer periphery of the center part 30 and prevented from being displaced; a pressure sensitive element 38 which has a vibration arm 40 as a pressure sensitive part defining a detection axis in the displacing direction of the center part and a pair of base parts (a first base part 42 and a second base part 44) holding the vibration arm 40, and in which the first base part 42 is fixed to one face of the center part 30; a ring part 22 arranged on the outer peripheral side of the diaphragm 28 and having a level difference part 27 on a principal surface positioned on the side where the pressure sensitive element 38 is arranged; a support plate body 50 connecting the second base part 44 of the pressure sensitive element 38 to the peripheral part 34 of the diaphragm 28 or to the level difference part 27; and stoppers 60 and 64 arranged parallel to the support plate body 50 and preventing the pressure sensitive element 38 from tilting.

Description

  The present invention relates to a pressure sensor using a pressure sensitive element and a diaphragm, and more particularly to a pressure sensor capable of improving resistance to impact from a direction perpendicular to the pressure sensitive element arrangement surface.

  Conventionally, a pressure sensor using a piezoelectric vibration element as a pressure-sensitive element is known as a water pressure gauge, a barometer, a differential pressure gauge, or the like. The pressure sensor having such a configuration includes a pressure-sensitive element in which an electrode pattern capable of exciting vibration is formed on a plate-shaped quartz substrate. And it comprises so that the detection axis | shaft of a pressure sensitive element may be matched with the detection direction of force. With such a configuration, a resonance frequency of vibration excited by the pressure-sensitive element is changed by applying force (pressure) in the arrangement direction of the detection shaft. For this reason, the applied pressure can be detected by converting the change in the resonance frequency into a force.

  As a pressure sensor based on such a configuration, one disclosed in Patent Document 1 is conventionally known. As shown in FIG. 13, the pressure sensor disclosed in Patent Document 1 is configured based on an airtight case 2, first and second bellows 3 a and 3 b, a piezoelectric vibration element 4, and an oscillation circuit 5. . The airtight case 2 has a cylindrical outer shell, and the inside thereof is a vacuum or an inert atmosphere. The first and second bellows 3a and 3b are arranged inside the airtight case 2 so as to cover the through holes (pressure input ports) 8 formed in the pair of end plates 6a and 6b constituting the outer shell of the airtight case 2, respectively. Placed in. A vibrator bonding base 7 is provided between the first and second bellows 3a and 3b. The vibrator bonding base 7 disposed between the first and second bellows 3a and 3b that expands and contracts according to the pressure applied from the pressure input port 8 corresponds to the expansion and contraction of the first and second bellows 3a and 3b. Move between the end plates. The piezoelectric vibration element 4 is disposed between any one of the end plates 6a (6b) constituting the airtight case 2 and the vibrator bonding pedestal 7, and has a resonance frequency due to stress accompanying the movement of the vibrator bonding pedestal 7. It is set as the structure which changes. The oscillation circuit 5 is electrically connected to an excitation electrode constituting the piezoelectric vibration element 4, and excites the piezoelectric vibration element 4 and detects excited vibration. And the differential pressure | voltage of the pressure provided between the 1st, 2nd bellows 3a and 3b can be detected by the change of the resonance frequency of the detected vibration.

  However, the pressure sensor 1 disclosed in Patent Document 1 has a problem in that a detection pressure error caused by a difference in thermal expansion coefficient between the airtight case 2 and the piezoelectric vibration element 4 is large.

  The inventors of the present application have proposed a pressure sensor disclosed in Patent Document 2 as a pressure sensor that suppresses errors caused by differences in thermal expansion coefficients and enables highly accurate pressure detection. As shown in FIG. 14, the pressure sensor disclosed in Patent Document 2 is basically configured of a piezoelectric vibration element 4a, a housing 2a that accommodates the piezoelectric vibration element 4a, and a diaphragm 3c provided at one end of the housing 2a. . The other end of the housing 2a facing the diaphragm 3c is sealed, and the inside of the housing 2a is set to a vacuum or an inert atmosphere. The diaphragm 3c includes a central part, a flexible part, and a peripheral part, and the central part located on the inner peripheral side of the flexible part functions as a pressure receiving part. The piezoelectric vibration element 4a is basically configured to include a vibration part 4a1 and a pair of base parts 4a2 and 4a3 at both ends of the vibration part 4a1. In the piezoelectric vibration element 4a, one of the base portions 4a2 is connected to the center portion of the diaphragm 3c, and the support plate 7a extending from the other base portion 4a3 is connected to the hermetic terminal 9 provided at the peripheral portion of the diaphragm 3c. It is configured to be connected and to be electrically connected to the outside. According to the pressure sensor 1a having such a configuration, since both ends of the piezoelectric vibration element 4a are connected to the diaphragm 3c, it is possible to suppress an error in detection pressure caused by a difference in thermal expansion coefficient.

JP 2007-57395 A JP 2010-48798 A

  If it is a pressure sensor of composition as indicated in patent documents 2, certainly the error of the detection pressure by the difference in a thermal expansion coefficient can be controlled, and highly accurate pressure detection can be performed. However, the pressure sensor disclosed in Patent Document 2 employs a configuration in which the piezoelectric vibration element is fixed to the diaphragm in a so-called cantilever state. For this reason, there exists a tendency for the tolerance to the impact of the surface direction of a piezoelectric vibration element, ie, the direction perpendicular | vertical to the same plane containing the vibration part 4a1 and base 4a2, 4a3, to become low.

  Therefore, an object of the present invention is to provide a pressure sensor that can detect pressure with high accuracy and has high resistance to impact in a direction perpendicular to the surface direction of the piezoelectric vibration element.

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 diaphragm having a central portion that is displaced in the pressure receiving direction, a peripheral portion that is located on the outer periphery of the central portion and is prevented from being displaced, and a detection axis along the displacement direction of the central portion. A pressure-sensitive element having a defined pressure-sensitive part and a pair of base parts sandwiching the pressure-sensitive part, and fixing one of the base parts to one surface of the central part of the diaphragm; and an outer periphery of the diaphragm A ring portion that is disposed on the side and includes a step portion on a main surface located on the pressure-sensitive element placement side, and one of the other base portions of the pressure-sensitive element is connected to the peripheral portion of the diaphragm or the step portion. A pressure sensor comprising: a support plate main body; and a stopper that is disposed in parallel with the support plate main body and prevents the pressure sensitive element from tilting.

  By setting it as such a structure, the stopper arrange | positioned in parallel with a support plate main body will prevent inclination of a pressure sensitive element. As a result, it is possible to increase resistance to impact in the direction orthogonal to the detection axis, that is, the principal surface direction of the pressure sensitive element.

Application Example 2 In the pressure sensor according to Application Example 1, the support plate body and the stopper are line-symmetrically on the same plane as the main surface of the pressure-sensitive element with the pressure-sensitive element as a base point. A pressure sensor characterized by being provided.
By adopting such a configuration, it is possible to prevent the pressure-sensitive element from being twisted when subjected to an impact in the main surface direction.

Application Example 3 In the pressure sensor according to Application Example 1 or Application Example 2, the pressure sensor includes a beam portion that connects the other base portion and the support plate body, and the stopper has a base point at the beam portion. A first stopper and a second stopper having a base point at the stepped portion, wherein the free end of the first stopper faces the stepped portion and has a gap between the stepped portion and the second stopper. The free end faces the beam portion and has a gap between the beam portion, and the gap is formed on the main surface opposite to the main surface having the beam portion in the first stopper and the second stopper. A pressure sensor characterized by being provided.
With such a configuration, the first stopper and the second stopper can be prevented from tilting in different directions.

Application Example 4 The pressure sensor according to Application Example 3, wherein the support plate main body and at least one of the first stopper and the second stopper are integrally formed.
With such a configuration, the number of components constituting the pressure sensor can be reduced, and manufacturing costs can be reduced and productivity can be improved.

[Application Example 5] The pressure sensor according to Application Example 1 or Application Example 2, wherein the pressure-sensitive element, the support plate body, and the stopper are integrally formed, and the tip end portion of the stopper and the step portion A pressure sensor characterized by providing a gap between them.
Also with such a configuration, the number of components constituting the pressure sensor can be reduced, and the manufacturing cost can be reduced and the productivity can be improved.

[Application Example 6] The pressure sensor according to Application Example 5, wherein the stopper is branched from the support plate body.
According to such a configuration, it is possible to adjust the strength of impact for the stopper to function.

It is a partial section permeation | transmission perspective view of the pressure sensor which concerns on 1st Embodiment. It is an enlarged side view which shows the connection state of the level | step-difference part in the pressure sensor which concerns on 1st Embodiment, a support plate main body, and a beam part. It is a partial transmission perspective view for demonstrating the action | operation of a stopper when a pressure sensitive element tilts, (A) is a stationary state, (B) is the state inclined in the + Y-axis direction, (C) is -Y-axis direction Shown in the state of tilting. It is a schematic diagram for demonstrating the manufacturing process of the pressure sensitive element and support plate unit in the pressure sensor which concerns on 1st Embodiment. It is a figure which shows the modification of the pressure sensor which concerns on 1st Embodiment. It is a figure which shows the modification of the support plate unit employ | adopted as the pressure sensor which concerns on 1st Embodiment. It is a partial section permeation | transmission perspective view of the pressure sensor which concerns on 2nd Embodiment. It is a figure which shows the modification of the support plate unit employ | adopted as the pressure sensor which concerns on 2nd Embodiment. It is a partial section permeation | transmission perspective view of the pressure sensor which concerns on 3rd Embodiment. It is a figure which shows the modification of the support plate unit employ | adopted as the pressure sensor which concerns on 3rd Embodiment. It is a perspective view which shows the modification of the ring part employ | adopted as the pressure sensor which concerns on 3rd Embodiment. It is a partial section permeation | transmission perspective view which shows the example of the pressure sensor which employ | adopted the AT cut quartz-crystal vibrating piece as the pressure sensitive element. It is a figure which shows the structure of the conventional type pressure sensor using a bellows. It is a figure which shows the structure of the conventional type pressure sensor which suppressed the influence of the thermal distortion with respect to a pressure sensitive element.

Hereinafter, embodiments of the pressure sensor of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a partially sectional transparent perspective view of the pressure sensor according to the first embodiment. In FIG. 1, the X axis indicates the axis extending to the right side (-X) and the left side (+ X) in the drawing, and the Y axis indicates the axis extending to the front side (+ Y) and the back side (-Y) in the drawing. , Z axis indicates an axis extending in the upper side (-Z) and the lower side (+ Z) in the figure. Note that XYZ shown in FIG. 1 forms an orthogonal coordinate system, and the same applies to figures used thereafter.

  The pressure sensor 10 according to the first embodiment is configured based on a housing 12, a diaphragm 28, and a pressure sensitive element 38. In the pressure sensor 10 having such a basic configuration, for example, when the inside of the housing is opened to the atmosphere, it can be used as a hydraulic pressure sensor that receives hydraulic pressure from the outside of the diaphragm with reference to atmospheric pressure. When the inside of the housing is vacuum-sealed, it can be used as an absolute pressure sensor based on vacuum.

  The housing 12 includes a circular sealing plate 14, a circular ring portion 22, a cylindrical side wall portion 20, and a support shaft (not shown). The sealing plate 14 has a flange portion 16 and a boss portion 18. Since the flange portion 16 is configured to be in contact with the end portion of the cylindrical side wall portion 20, the flange portion 16 has an outer shape larger than the inner diameter of the side wall portion 20. On the other hand, since the boss portion 18 is configured to be fitted into the cylindrical side wall portion 20, the boss portion 18 has an outer shape having a minus tolerance with respect to the inner diameter of the side wall portion 20.

  The ring portion 22 is a ring-shaped member provided at the end of the side wall portion 20 opposite to the end where the sealing plate 14 is disposed. Since it is disposed on the inner peripheral side of the side wall portion 20, its outer diameter has a minus tolerance with respect to the inner periphery of the side wall portion 20, and an opening 23 provided on the inner side has a diaphragm 28, which will be described in detail later. Is provided. The ring portion 22 in the present embodiment is configured to have a thick portion 24 and a thin portion 26 having different thicknesses for each semicircle. For this reason, it will have the level | step-difference part 27 which makes a pair in the relative position of 180 degrees centering on a center.

  A hole (not shown) into which a support shaft (not shown) is fitted is formed on the opposing surface of the boss part 18 and the ring part 22 of the sealing plate 14 at the opposing position. Therefore, by inserting the support shaft into the hole, the sealing plate 14 and the ring portion 22 are connected and positioned through the support shaft. The support shaft is a rod-like member that has a certain rigidity and is arranged with the longitudinal direction aligned with the ± Z direction. The number and arrangement of the support shafts are arbitrarily determined according to the specifications of each pressure sensor.

  A hermetic terminal 70 is attached to the sealing plate 14. The hermetic terminal 70 is electrically connected to an electrode portion (not shown) of a pressure sensitive element 38 described later via a wire 72. With such a configuration, even the pressure-sensitive element 38 sealed in the housing 12 can apply a voltage to the electrode portion via the hermetic terminal 70. Therefore, the external surface of the housing 12 or the IC (integrated circuit (not shown)) arranged outside the housing 12 and spaced from the housing 12 is electrically connected to the electrode portion of the pressure-sensitive element 38. Is also possible.

  Although two hermetic terminals 70 are illustrated in FIG. 1, the number of the hermetic terminals 70 can be increased or decreased according to the total number of electrode portions (not shown) of the pressure sensitive element 38. When used as the above-described hydraulic pressure sensor, the sealing plate 14 can be provided with an air inlet (not shown) so that the inside of the housing can be opened to the atmosphere.

  The sealing plate 14, the ring part 22, and the side wall part 20 configured as described above are preferably formed of a metal such as stainless steel, and a support shaft (not shown) has a certain rigidity and has a small thermal expansion coefficient. Etc. are preferably used.

  The diaphragm 28 has one main surface facing the outside of the housing 12 as a pressure receiving surface, and the pressure receiving surface has a flexible portion 32 that bends and deforms under the pressure of a measured pressure environment (for example, liquid). When the flexible portion 32 is bent and deformed so as to be displaced to the inside or outside (Z-axis direction) of the housing 12, a compressive stress or a tensile stress along the Z-axis is transmitted to the pressure-sensitive element 38. The diaphragm 28 has at least a central portion 30, a flexible portion 32, and a peripheral edge portion 34. The central portion 30 is a pressure receiving portion that is displaced by external pressure, and the flexible portion 32 is on the outer periphery of the central portion. When the diaphragm 28 receives external pressure, it is bent and deformed. This is a portion where the central portion 30 can be displaced. The peripheral portion 34 is a portion that is provided outside the flexible portion 32, that is, on the outer periphery of the flexible portion 32, and is bonded and fixed to the inner wall of the opening 23 formed in the ring portion 22. Ideally, the peripheral portion 34 is not displaced even when subjected to pressure, and the central portion 30 is not deformed even when subjected to pressure.

  The material of the diaphragm 28 is preferably a material having excellent corrosion resistance such as a metal such as stainless steel or ceramic, and may be a single crystal such as quartz or another non-crystalline material. For example, in the case of forming with metal, the metal base material may be formed by pressing, and in the case of forming with crystal, photolithography / etching may be performed so that the flexible portion becomes thinner than other portions.

  The diaphragm 28 may be coated with a corrosion-resistant film on the surface exposed to the outside so as not to be corroded by liquid or gas. For example, if the diaphragm 28 is made of metal, a nickel compound or the like may be coated. Further, when the constituent member of the diaphragm 28 is a piezoelectric crystal such as quartz, silicon or the like may be coated.

  A support portion 36 is provided at the central portion 30 of the diaphragm 28. A first base 42 of the pressure sensitive element 38 is connected to the support portion 36. A beam portion 46 is connected to the second base portion 44 of the pressure sensitive element 38, and the beam portion 46 is supported by a pair of support plate units 48. The beam portion 46 is a plate member having a longitudinal direction in a direction (± X axis direction) orthogonal to the displacement direction of the central portion 30, and is configured to connect the second base portion 44 in the pressure sensitive element 38 to the center in the longitudinal direction. It is said that.

  The beam portion 46 is desirably formed of a material having the same thermal expansion coefficient as that of the diaphragm 28 serving as the pressure receiving means, or the same material (stainless steel) as the diaphragm 28. With such a configuration, the expansion / contraction ratios of the diaphragm 28 and the beam portion 46 coincide with each other in the direction (X-axis direction) perpendicular to the detection axis (Z-axis direction) of the pressure-sensitive element 38. . For this reason, the difference in the thermal expansion coefficient between the beam portion 46 and the diaphragm 28 reduces the support plate unit 48 from receiving thermal strain in the X-axis direction. It is also possible to reduce thermal distortion.

  The support plate unit 48 is a plate member that is provided at symmetrical positions on both ends of the beam portion 46 and holds the height of the beam portion 46 in the Z-axis direction. By providing the support plate unit 48, when the central portion 30 of the diaphragm 28 is displaced, the pressure sensitive element 38 receives an extension stress or a compressive stress with the beam portion 46 as a base point, and the resonance frequency changes. . The support plate unit 48 according to the present embodiment includes a support plate main body 50 and a pair of stoppers 60 and 64, and one end 52 in the support plate main body 50 is used as the stepped portion 27 in the ring portion 22 and the other end. 54 are connected to the ends of the beam portions 46, respectively. The stoppers 60 and 64 are arranged at the center of the support plate main body 50 from one end 52 (or near one end 52) and the other end 54 (or near the other end 54) of the support plate main body 50. This is a section extending along the support plate main body 50 with the connecting portions 56 and 58 extending so as to be symmetrical about the base point as the base point. That is, the stopper 60 extended from the connecting portion 56 provided on the one end portion 52 side is extended toward the other end portion 54 side. On the other hand, the stopper 64 extended from the connecting portion 58 provided on the other end 54 side is extended toward the one end 52 side. Therefore, the support plate unit 48 has a substantially S-shaped configuration as a whole. Of the stoppers 60 and 64 in the support plate unit 48 having such a configuration, the stopper 60 having a base point on one end 52 side has a length that allows the free end 62 to overlap the beam portion 46. Further, the stopper 64 having a base point on the other end 54 side has a length that allows the free end 66 to overlap the stepped portion 27. The support plate unit 48 is preferably made of the same material as the pressure-sensitive element 38 or a material having the same thermal expansion coefficient, such as quartz, lithium niobate, and lithium tantalate. This is because by adopting such a configuration, it is possible to suppress thermal strain applied to the pressure sensitive element 38 from the support plate unit 48.

  The connection between the support portion 36 and the support plate unit 48, and the beam portion 46 and the support plate unit 48 are each made of an adhesive 68. The adhesive 68 is not particularly limited, and examples thereof include an epoxy adhesive. Further, as shown in FIG. 2, the support portion 36, the support plate unit 48, and the beam portion 46 are connected so that the structure viewed from the side is a laminated structure. Since the adhesive 68 used for the connection has a thickness, a gap is provided between the beam portion 46 and the free end 62 of the stopper 60 and between the step portion 27 and the free end 66 of the stopper 64.

  With such a configuration, when the pressure sensitive element 38 is tilted, the stoppers 60 and 64 function as shown in FIG. That is, as shown in FIG. 3B, when the pressure sensitive element 38 is tilted in the + Y-axis direction, the free end 66 of the stopper 64 comes into contact with the stepped portion 27, and further tilting is suppressed. Become. On the other hand, as shown in FIG. 3C, when the pressure-sensitive element 38 is tilted in the −Y-axis direction, the free end 62 of the stopper 60 comes into contact with the beam portion 46 to suppress further tilting. It becomes. For this reason, the tolerance with respect to the impact of the direction (Y-axis direction) orthogonal to a detection axis (Z-axis direction) can be improved. In FIG. 3, FIG. 3A is a perspective view showing a state where the pressure sensitive element 38 is not tilted.

  The pressure-sensitive element 38 used in the present embodiment includes a vibrating arm 40 that is a pressure-sensitive portion, and a first base portion 42 and a second base portion 44 that are disposed so as to sandwich the vibrating arm 40. As described above, the first base portion 42 is connected to the support portion 36 provided in the central portion 30 of the diaphragm 28 via the adhesive 68. On the other hand, the second base portion 44 is connected to the central portion in the longitudinal direction of the beam portion 46 described above via an adhesive 68. An excitation electrode (not shown) is formed on the vibrating arm 40 of the pressure-sensitive element 38, and an electrode portion (not shown) electrically connected to the excitation electrode (not shown) is provided on the second base 44. .

  The pressure-sensitive element 38 having such a configuration has a longitudinal direction (Z-axis direction), that is, a direction in which the first base portion 42 and the second base portion 44 are arranged as a displacement direction (Z-axis direction) of the diaphragm 28. It arrange | positions so that it may be coaxial or parallel, The displacement direction serves as a detection axis.

  The pressure sensitive element 38 is electrically connected to an IC (not shown) via a hermetic terminal 70 and a wire 72, and vibrates at an inherent resonance frequency by an AC voltage supplied from the IC (not shown). And the pressure frequency of the pressure-sensitive element 38 fluctuates by receiving an elongation stress or a compressive stress from the longitudinal direction (Z-axis direction). In the present embodiment, a double tuning fork vibrator can be applied as the vibrating arm 40 serving as a pressure-sensitive portion. The characteristic of the double tuning fork vibrator is that when a tensile stress (elongation stress) or a compressive stress is applied to the two vibrating beams that are the vibrating arms 40, the resonance frequency thereof changes approximately in proportion to the applied stress. There is. The double tuning fork type piezoelectric resonator element has a very large resonance frequency change with respect to elongation / compression stress and a large variable range of the resonance frequency compared to a thickness shear vibrator, etc. It is suitable for a pressure sensor that excels in resistance. Note that the double tuning fork type piezoelectric vibrator has a property that the resonance frequency of the vibrating arm 40 is increased when subjected to an extension stress, and the resonance frequency of the vibrating arm 40 is decreased when subjected to a compressive stress.

  Here, in the example shown in FIG. 1, an example in which a so-called double tuning fork type piezoelectric vibrating piece having two columnar vibrating beams is used as the pressure-sensitive element 38 is shown. However, the pressure sensitive element that can be employed in the present embodiment is not limited to this. For example, as the pressure sensitive element, an element having a pressure sensitive part composed of a single vibration beam (single beam) can be applied. If the pressure-sensitive part (vibrating arm) is configured as a single beam type vibrator, the displacement is doubled when subjected to the same stress from the longitudinal direction (detection axis direction), which is higher than in the case of a double tuning fork. It can be a sensitive pressure sensor. Of the above-described piezoelectric materials, quartz having excellent temperature characteristics is desirable for a piezoelectric substrate of a double tuning fork type or single beam type piezoelectric vibrator. Naturally, not only a bending vibration type pressure-sensitive element but also a vibrator that excites a thickness-shear type vibration or a vibrator that excites a surface acoustic wave can be adopted as the pressure-sensitive element.

  FIG. 4 shows a schematic diagram of a manufacturing process when the pressure-sensitive element 38 and the support plate unit 48 are made of quartz. In the case of forming with quartz, it is preferable to form by photolithography and etching as described above. First, a mother substrate 100 as a material is prepared, and a positive photoresist 102 is applied to the surface of the mother substrate 100 (FIG. 4A). Next, exposure is performed using a pressure sensitive element 38 and a photomask (not shown) corresponding to the shape of the support plate unit 48, and the photoresist 102 is exposed to form a photosensitive portion 104 (FIG. 4B). . Thereafter, development is performed to remove the photoresist corresponding to the photosensitive portion 104 (FIG. 4C). Next, the pressure sensitive element 38 and the support plate unit 48 are formed by etching the region where the mother substrate 100 is exposed (FIG. 4D), and the photoresist 102 is peeled off (FIG. 4E). .

In assembling the pressure sensor 10 according to the first embodiment, the diaphragm 28 is first connected to the ring portion 22, and the support portion 36 is disposed at the central portion 30 of the diaphragm 28. Thereafter, the diaphragm 28 and the ring portion 22 are held using a jig (not shown), the first base portion 42 of the pressure sensitive element 38 is connected to the support portion 36, and one end of the support plate main body 50 is connected to the step portion 27. The unit 52 is connected. Thereafter, the beam portion 46 is connected to the second base portion 44 of the pressure-sensitive element 38 and the other end portion 54 of the support plate main body 50.
According to the pressure sensor 10 having such a configuration, as described above, it is possible to improve resistance to impact in a direction (Y-axis direction) orthogonal to the detection axis (Z-axis direction).

  Next, a support shaft (not shown) for positioning the ring portion 22 is disposed on the sealing plate 14, and the inner side of the housing of the hermetic terminal 70 and the electrode portion (not shown) of the pressure sensitive element 38 are electrically connected by a wire 72. Connect to. At this time, the outside of the housing of the hermetic terminal 70 is connected to an IC (not shown). Finally, the side wall part 20 is inserted from the ring part 22 side, and the housing 12 is formed by joining the end part of the side wall part 20 to the flange part 16 of the sealing plate 14 and the outer periphery of the ring part 22, respectively. 10 is assembled. When the pressure sensor 10 is a pressure sensor that measures an absolute pressure with reference to a vacuum, the pressure sensor may be assembled in a vacuum without forming the air inlet.

  Operation | movement of the pressure sensor 10 of 1st Embodiment is demonstrated. In the first embodiment, when the hydraulic pressure is measured based on the atmospheric pressure, if the hydraulic pressure is lower than the atmospheric pressure, the central portion 30 of the diaphragm 28 is displaced to the inside of the housing 12, and conversely the hydraulic pressure is higher than the atmospheric pressure. The central portion 30 is displaced to the outside of the housing 12.

  When the central portion 30 of the diaphragm 28 is displaced to the outside of the housing 12, the pressure sensitive element 38 is interposed between the central portion 30 and the beam portion 46 supported by the support plate body 50 connected to the ring portion 22. Subject to tensile stress. Conversely, when the central portion 30 is displaced to the inside of the housing 12, the pressure sensitive element 38 receives a compressive stress between the central portion 30 and the beam portion 46.

  Further, in the pressure sensor 10, when the temperature changes, the housing 12, the diaphragm 28, the support plate unit 48, the beam portion 46, the pressure-sensitive element 38, and the like constituting the pressure sensor 10 are expanded and expanded according to their respective thermal expansion coefficients. Will contract.

  However, as described above, in the pressure-sensitive element 10, the first base portion 42 is fixed to the central portion 30 of the diaphragm 28, and the second base portion 44 is connected to the ring portion 22 via the beam portion 46 and the support plate unit 48. It is fixed to. The ring portion 22 and the beam portion 46 are made of the same member as the member constituting the diaphragm 28 or a member having a similar thermal expansion coefficient, and the support plate unit 48 is the same member as the pressure sensitive element 38. It is comprised by. For this reason, the thermal strain applied to the pressure sensitive element 38 due to the temperature change is in both the direction perpendicular to the detection axis (Z-axis direction) (X-axis and Y-axis directions) and the direction parallel to the detection axis (Z-axis direction). Will be reduced.

In the pressure sensor 10 according to the above-described embodiment, the support plate unit 48 is disposed at both ends of the beam portion 46 so as to have a line-symmetric relationship. However, the pressure sensor 10 according to the present embodiment may be configured as shown in FIG. That is, the support plate unit 48 is arranged at one end of the beam portion 46 and only the support plate main body 50 is arranged at the other end.
Even in such a configuration, the support plate unit 48 can prevent the pressure-sensitive element 38 from tilting in the Y-axis direction. Therefore, similarly to the above-described embodiment, resistance to impact from the Y-axis direction can be improved.

  FIG. 6 shows a modified form of the support plate unit in the pressure sensor 10 according to the present embodiment. The support plate main body 50 in the support plate unit 48 in the above embodiment is provided with connection portions 56 and 58 on one end portion 52 side or the other end portion 54 side so as to be point-symmetric. The stoppers 60 and 64 are extended from 58 as a base point. On the other hand, in the embodiment shown in FIG. 6, connection portions 56 and 58 are provided near the center of the support plate main body 50, and one end portion 52 side or the other end portion 54 side with the connection portions 56 and 58 as base points, respectively. The stoppers 60 and 64 are extended so that the free ends 62 and 66 are arranged.

  In such a configuration, the impact strength for applying the stoppers 60 and 64 can be adjusted by adjusting the positions of the connecting portions 56 and 58. That is, the closer the connecting portions 56 and 58 are to the end portion side where the free ends 62 and 66 are located (one end portion 52 or the other end portion 54), the stopper functions in a stronger impact.

  In the pressure sensor 10 according to the above-described embodiment, the stoppers 60 and 64 are formed integrally with the support plate main body 50 in order to improve productivity, thereby constituting a support plate unit. However, of course, in the pressure sensor 10 according to the present embodiment, the stoppers 60 and 64 and the support plate main body 50 may be individual members. However, in the case of such a configuration, when the stoppers 60 and 64 and the support plate main body 50 are fixed to the stepped portion 27 and the beam portion 46, it is necessary to individually apply the adhesive 68.

  Next, a second embodiment according to the pressure sensor of the present invention will be described with reference to FIG. The configuration of the pressure sensor according to this embodiment is almost the same as that of the pressure sensor 10 according to the first embodiment. Therefore, portions having the same configuration are denoted by the same reference numerals in the drawings, and detailed description thereof is omitted.

  The difference between the pressure sensor according to the present embodiment and the pressure sensor 10 according to the first embodiment is the configuration of the support plate unit. Specifically, the support plate unit 48 in the pressure sensor 10 according to the first embodiment has an S-shaped planar form, whereas the support plate unit 48b of the pressure sensor according to the present embodiment has a planar form. Is U-shaped.

  The support plate unit 48 of the pressure sensor 10 according to the first embodiment includes the connection portions 56 and 56 so as to be arranged symmetrically with respect to the one end portion 52 and the other end portion 54 of the support plate main body 50. 58 is disposed, and the stoppers 60 and 64 are extended from both sides, so that the planar form is S-shaped. On the other hand, the support plate unit 48b according to the present embodiment is connected to one end 52 of the support plate main body 50 or the other end 54 (the other end 54 in the example shown in FIG. 7). Since the portion 56a is provided and the stopper 60 is extended to one of the other (one end portion 52 in the example shown in FIG. 7), the planar shape is U-shaped.

The support plate unit 48b having such a planar shape takes a point-symmetric arrangement form with the pressure sensitive element 38 as a base point. That is, when one support plate unit 48 b connects one end to the stepped portion 27, the other support plate unit 48 b takes an arrangement form in which the other end 54 is connected to the stepped portion 27. By adopting such an arrangement, when the pressure sensitive element 38 is tilted toward the front side (+ Y axis side) in the figure, the stopper 60 in the support plate unit 48b in which one end portion 52 is connected to the stepped portion 27. The free end 62 comes into contact with the stepped portion 27 to suppress tilting. On the other hand, when the pressure sensitive element 38 is tilted to the back side (−Y axis side) in the drawing, the free end 62 of the stopper 60 in the support plate unit 48b in which the other end portion 54 is connected to the stepped portion 27 is the beam portion. 46 is brought into contact with and the tilting is suppressed. Therefore, in the support plate unit 48b having such a configuration, a pair of the support plate units 48b increases resistance to an impact in a direction orthogonal to the detection axis.
In addition, about another structure, an effect | action, and an effect, it is the same as that of the pressure sensor 10 which concerns on 1st Embodiment mentioned above.

  FIG. 8 shows a modified form of the support plate unit according to the present embodiment. In the support plate unit 48b in the above embodiment, a connection portion 56a is provided on either the one end portion 52 side or the other end portion 54 side of the support plate main body 50, and the stopper 60 is provided with the connection portion 56a as a base point. The configuration was extended. On the other hand, in the form shown in FIG. 8, a connection portion 56a is provided near the center of the support plate main body 50 in the support plate unit 48c, and one end portion 52 side and the other end portion 54 side are based on this connection portion 56a. The stopper 60 is extended so that the free ends 62 are arranged on both sides. In such a configuration, the impact strength for applying the stopper 60 can be adjusted by adjusting the position of the connecting portion 56a.

  Next, a third embodiment according to the pressure sensor of the present invention will be described with reference to FIG. The configuration of the pressure sensor according to this embodiment is almost the same as that of the pressure sensor 10 according to the first embodiment. Therefore, portions having the same configuration are denoted by the same reference numerals in the drawings, and detailed description thereof is omitted.

  The difference between the pressure sensor according to the present embodiment and the pressure sensor 10 according to the first embodiment is the relationship between the pressure-sensitive element 38, the beam portion 46, the support plate body 50a, and the stopper 60a. Specifically, in the pressure sensor 10 according to the first embodiment, the pressure-sensitive element 38, the beam portion 46, and the support plate main body 50 (support plate unit 48) are configured by separate members, and these are adhesives 68. It was set as the structure which connects via. In contrast, the pressure sensor according to the present embodiment is characterized in that the pressure-sensitive element 38, the beam portion 46, the support plate main body 50a, and the stopper 60a are integrally formed of the same member.

  In the pressure sensor according to the present embodiment, one end 52 of the support plate main body 50 a is connected to the support plate support 80 provided on the peripheral edge 34 of the diaphragm 28 via an adhesive 68. This is because the bending of the peripheral edge portion 34 of the diaphragm 28 is suppressed, and the support plate body 50a can be stably fixed. In such a configuration, a hermetic terminal (not shown) is disposed on the peripheral edge 34 of the diaphragm 28, and one end 52 of the support plate body 50a is connected and fixed to the hermetic terminal. May be. If electrodes are formed on the support plate main body 50a, it is not necessary to use a wire for electrical connection between the hermetic terminal and the electrode portion of the pressure-sensitive element 38, and connectivity is improved. In FIG. 9, the planar shape of the support plate main body 50 a is a crank shape, but the support plate main body 50 a may be vertically lowered from the beam portion 46 to the peripheral edge portion 34.

  In this embodiment, since the pressure-sensitive element 38, the beam portion 46, the support plate main body 50a, and the stopper 60a are integrally formed, the contact surface of the free end of the stopper 60a is a stepped portion in the ring portion 22a. 27 only. Therefore, the beam portion 46 extends from the other end portion 54 (base point) of the support plate main body 50a to a position directly above the ring portion 22a on the side wall portion (not shown) side. The stopper 60 a is extended from both ends of the beam portion 46 toward the ring portion 22 a, and is arranged at a position where the free end 62 can come into contact with the stepped portion 27.

  In the pressure sensor 10 according to the first embodiment, the thick portion 24 is formed in a semicircular shape in the ring portion 22, and the stepped portion 27 is provided symmetrically with respect to the pressure sensitive element 38. On the other hand, in the pressure sensor according to the present embodiment, the thick portion 24 is formed at a point-symmetrical position with respect to the pressure sensitive element 38, and one stepped portion 27 is disposed on one main surface side of one stopper 60a. In this case, the other stepped portion 27 is arranged on the other main surface side of the other stopper 60a. By adopting such a configuration, the free end 62 of any one of the stoppers 60a becomes the step portion even when the pressure sensitive element is tilted to the + Y axis side or the −Y axis side. 27, it is possible to suppress tilting.

  Further, in the embodiment shown in FIG. 9, it is described that the support plate main body 50a is extended from the beam portion 46 as a base point. However, as shown in FIG. 10, the support plate body may be configured to extend from the stopper 60b as a base point. In such a configuration, since the stopper 60b is positioned on the ring portion 22a, the support plate main body 50b is extended from the intermediate portion of the stopper 60b to the pressure-sensitive element 38 side, and then the first It extends toward the base 42 side. By setting it as such a structure, the one edge part 52 of the support plate main body 50b will be located on the peripheral part 34 (refer FIG. 9) of the diaphragm 28 (refer FIG. 9).

  Thus, by extending the support plate main body 50b with the stopper 60b as a base point, it is possible to adjust the impact strength at which the stopper 60b functions depending on the position of the base point of the support plate main body 50b.

  In the above-described embodiment, the stepped portion 27 is shown to be disposed only on one of the main surface side or the other main surface side of the pair of stoppers 60a (60b). However, by making the configuration of the ring portion as shown in FIG. 11, the stepped portions 27 are respectively arranged on one main surface side and the other main surface side of each stopper 60a (60b). It becomes. That is, after making the entire circumference of the ring portion 22b a thick portion 24, a groove-like thin portion 26 is formed at a line symmetrical position with the center of the ring portion 22b as a base point. By setting it as such a structure, the level | step-difference part 27 will be provided so that a so-called groove | channel side wall may be comprised. And the free end 62 of the stopper 60a (60b) should just take the form inserted in this groove | channel.

  Further, the pressure sensor according to the present invention may be a differential pressure type pressure sensor by providing a diaphragm (for example, a second diaphragm (not shown)) at a sealing plate mounting position in the housing. In the case of such a configuration, for example, the support portion 36 shown in FIG. 1 may be extended and connected to the center portion of the second diaphragm provided at the opposed position. Thereby, the support part 36 functions as a force transmission shaft which transmits the pressure loaded on both diaphragms between the 1st diaphragm (diaphragm 28) and the 2nd diaphragm.

  FIG. 12 is a partial cross-sectional perspective view showing an example of a pressure sensor that employs the pressure-sensitive element 38a that excites thickness-slip vibration as described above. The AT-cut quartz crystal vibrating piece (pressure-sensitive element 38a) is constituted by a quartz chip obtained by cutting a quartz substrate parallel to the X axis and at an angle of about 35 degrees 15 minutes from the Z axis. A pair of excitation electrodes 39 are provided on both main surfaces of the AT-cut quartz crystal vibrating piece. Other configurations are the same as those of the pressure sensor according to the above-described embodiment. In general, an AT-cut quartz crystal vibrating piece has a higher resonance frequency than a tuning fork type quartz crystal vibrating piece. Therefore, the measurement speed is increased. Therefore, it can be applied to a pressure sensor for tire pressure and the like that require quick pressure measurement.

10 ......... Pressure sensor, 12 ......... Housing, 14 ......... Sealing plate, 16 ......... Flange, 18 ...... Boss, 20 ......... Side, 22 ...... Ring, 23 ......... Opening, 24 ......... Thick part, 26 ......... Thin part, 27 ......... Step part, 28 ......... Diaphragm, 30 ......... Center part, 32 ......... Flexible part, 34 ... peripheral edge, 36 ......... support, 38 ......... pressure sensitive element, 40 ...... vibrating arm, 42 ......... first base, 44 ......... second base, 46 ......... Beam part, 48 ......... Support plate unit, 50 ......... Support plate body, 52 ......... One end part, 54 ......... Other end part, 56 ......... Connection part, 58 ...... Connection part 60 ......... Stopper, 62 ......... Free end, 64 ......... Stopper, 66 ......... Free end, 68 ...... Adhesive, 70 ...... Hermetic terminal, 72 ...... wire.

Claims (6)

A diaphragm having a central portion that is displaced in the pressure-receiving direction, and a peripheral portion that is located on the outer periphery of the central portion and is suppressed from being displaced;
A pressure-sensitive portion having a detection axis defined along a displacement direction of the central portion; and a pair of base portions sandwiching the pressure-sensitive portion; and one of the base portions on one surface of the central portion of the diaphragm A fixed pressure sensitive element;
A ring portion that is disposed on the outer peripheral side of the diaphragm and includes a step portion on a main surface located on the pressure-sensitive element arrangement side;
A support plate body that connects the other base of the pressure sensitive element to the peripheral edge of the diaphragm or the stepped portion;
A pressure sensor, comprising: a stopper that is disposed in parallel with the support plate body and prevents the pressure sensitive element from tilting. The pressure sensor according to claim 1,
The pressure sensor according to claim 1, wherein the support plate body and the stopper are provided symmetrically on the same plane as the main surface of the pressure sensitive element with the pressure sensitive element as a base point. The pressure sensor according to claim 1 or 2,
A beam portion connecting the other base and the support plate body;
The stopper includes a first stopper having a base point on the beam portion and a second stopper having a base point on the step portion, and a free end of the first stopper is opposed to the step portion and between the step portion. And the free end of the second stopper is opposed to the beam portion and has a gap between the beam portion and the gap between the beam portion in the first stopper and the second stopper. It is provided in the main surface on the opposite side to the main surface which has a pressure sensor. The pressure sensor according to claim 3,
The pressure sensor, wherein the support plate main body and at least one of the first stopper and the second stopper are integrally formed. The pressure sensor according to claim 1 or 2,
The pressure sensor, wherein the pressure sensitive element, the support plate main body, and the stopper are integrally formed, and a gap is provided between a tip portion of the stopper and the stepped portion. The pressure sensor according to claim 5,
The pressure sensor, wherein the stopper is branched from the support plate body.

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