Sensing assembly for pressure sensor and pressure sensor

Abstract

The utility model relates to a sensing assembly used for a pressure sensor, the sensing assembly (1) comprises a channel housing (2) which is used for introducing a fluid medium and is provided with a hollow cylindrical cavity (3), one end of the channel housing (2) is sealed by a circular diaphragm (4) which is integrally formed with the channel housing (2); the diaphragm (4) can be deformed under the action of the fluid pressure of the fluid medium, the diaphragm (4) is provided with at least one strain gauge (8) in the radial direction on the side (4b) facing away from the fluid medium, and each strain gauge (8) comprises at least two varistors (8a, 8b) extending in the radial direction. In the utility model, in order to overcome a series of process problems caused by the thinning of the diaphragm, a circular bulge (5) is arranged in the middle on one side (4a) of the diaphragm, which faces a fluid medium. In addition, the utility model relates to a pressure sensor comprising the sensing assembly.

Description

Technical Field

[0001] This utility model relates to a sensing component for a pressure sensor and a pressure sensor. Background Technology

[0002] Pressure sensors based on microfused silicon strain gauges (MSGs) are widely used in many industries. For example, in the automotive industry, MSGs are used in a range of applications, from brake, transmission, and fuel pressure sensors to occupant gravity sensing. Such pressure sensors typically comprise silicon strain gauges, which utilize high-temperature glass bonded to a diaphragm, particularly a steel diaphragm, at the port of the pressure sensor using a microfusion technique. A Wheatstone bridge constructed from the individual piezoresistors within the silicon strain gauge can be used to generate a linear voltage output relating the strain of the diaphragm under fluid pressure in a fluid medium. This linear voltage output is calibrated to be proportional to the pressure applied to the diaphragm.

[0003] To measure fluid pressures in low-pressure ranges, such as below 20 bar, and especially 10 bar or lower, using such microfused silicon strain gauge (MSG)-based pressure sensors, the diaphragm needs to be designed to be extremely thin, for example, only 0.1 mm to 0.3 mm thick. However, this introduces additional processing challenges, such as the diaphragm's tendency to bulge and deform during sandblasting due to its thinness; the potential for strain gauge lead bonding failure on the diaphragm without robust support; and / or residual thermal stress during the bonding of the strain gauge to the diaphragm leading to imbalances in the sensed resistance.

[0004] Therefore, there is an urgent need for a sensing component for pressure sensors and a pressure sensor that can overcome the manufacturing problems caused by diaphragm thickness and have as little impact as possible on fluid pressure measurement. Utility Model Content

[0005] The objective of this invention is to provide a sensing component for a pressure sensor and a pressure sensor that overcomes the manufacturing challenges caused by diaphragm thickness and minimizes the impact on fluid pressure measurement.

[0006] The first aspect of this utility model relates to a sensing component for a pressure sensor, the sensing component comprising a channel housing having a hollow cylindrical cavity for introducing a fluid medium, the channel housing being closed at one end by a circular diaphragm integrally formed with the channel housing, the diaphragm being deformable under the fluid pressure of the fluid medium, the diaphragm having at least one strain gauge arranged radially on the side facing away from the fluid medium, each strain gauge comprising at least two piezoresistors extending radially, wherein the diaphragm has a circular protrusion centrally located on the side facing the fluid medium.

[0007] In this invention, the sensing component is specifically configured for a pressure sensor based on a microfused silicon strain gauge (MSG). This pressure sensor is particularly used for measuring fluid pressures in low-pressure ranges, such as below 20 bar, especially 10 bar or lower. To obtain pressure values ​​in such low-pressure ranges, the circular diaphragm of the sensing component needs to have a sufficiently thin thickness, such as 0.1 mm to 0.3 mm, so that subtle differences between different fluid pressures within this pressure range can be sensed by a strain gauge fixed thereon. Specifically, the fluid medium is loaded onto the diaphragm from one side. Under the fluid pressure of the fluid medium, the diaphragm can deform or bulge towards the side opposite to the fluid medium.

[0008] To sense this deformation, the diaphragm has at least one strain gauge arranged radially on the side facing away from the fluid medium. Exemplarily, two strain gauges can be arranged symmetrically in the radial direction, i.e., the two strain gauges are symmetrical about the center of the diaphragm in a straight line. Alternatively, two or more strain gauges can be arranged around the center of the diaphragm in the same radial range, all extending radially and spaced equidistant from the center of the diaphragm, with the included angle between the strain gauges being arbitrary, such as 60°, 90°, 120°, etc. Each strain gauge contains at least two piezoresistors extending radially. When there are two or more strain gauges, each strain gauge may, for example, contain two piezoresistors extending radially. Not limited to the above-mentioned cases, only one strain gauge in the radial direction may be provided, containing four piezoresistors extending radially in pairs. In the aforementioned schemes, four varistors on the diaphragm can form a Wheatstone bridge, allowing fluid pressure to be calculated based on the resistance values ​​of each varistor. When fluid pressure is applied to the diaphragm, the bulging deformation of the diaphragm causes a change in the resistance of one or more of these varistors. When a constant voltage is input to the four varistors, the change in resistance of one or more of the four varistors will cause a corresponding change in at least one of the bridge output voltages. The change in output voltage can be used to calculate the deformation of the diaphragm and the fluid pressure of the fluid medium.

[0009] However, at the aforementioned diaphragm thickness, diaphragms preferably made of steel, especially stainless steel, may cause a variety of process problems, such as the diaphragm being prone to bulging and deformation due to its thinness when sandblasting; the strain gauge wire bonding on the diaphragm being prone to failure without a strong support; and / or the residual thermal stress during the process of fixing the strain gauge to the diaphragm causing an imbalance in the sensed resistance.

[0010] To overcome the aforementioned process problems with minimal impact on pressure measurement, this invention proposes that the diaphragm have a centrally located circular protrusion on the side facing the fluid medium. This can be understood as selectively thickening the portion not involved in fluid pressure measurement, while maintaining or even further reducing the diaphragm thickness in the area involved in fluid pressure measurement. In other words, a thin annular region is formed across the entire diaphragm, and this annular region is used to house the at least one strain gauge. This design enables a sensing component structure suitable for measuring fluid pressures below 20 bar, particularly 10 bar or lower. Here, the protrusion serves as a reinforcing structure for the relatively thin diaphragm, enhancing its structural stability during sandblasting and wire bonding, preventing protrusion deformation during sandblasting, improving wire bonding yield, and preventing residual thermal stress when the strain gauge is bonded to the diaphragm, especially via micro-melting technology, thereby reducing resistance imbalance sensed by the strain gauge. Meanwhile, since the protrusion is located at the center of the diaphragm on the side facing the fluid medium, it interferes less with the strain gauges on the diaphragm, thus minimizing the impact on fluid pressure measurement.

[0011] It should be noted that the sensing component according to this utility model can also be called a port for a pressure sensor. It can be mechanically connected to the structural components of the pressure sensor (such as the housing, mounting structure, etc.) and electrically connected to the analysis circuit of the pressure sensor (such as the chip), thereby jointly forming a pressure sensor.

[0012] According to one embodiment of this invention, the protrusion may not coincide with the projected position of the at least one strain gauge in the axial direction of the channel housing. This means that, viewed from the axial position, the protrusion and the at least one strain gauge are misaligned, i.e., spaced apart from each other. Therefore, the protrusion hardly affects the deformation, particularly the radial deformation, at the location where the strain gauge is fixed, and thus hardly affects the fluid pressure measurement.

[0013] According to one embodiment of this invention, in the axial direction of the channel housing, at least one strain gauge can partially coincide with the peripheral wall of the channel housing. Here, the outermost piezoresistor of the at least one strain gauge will be partially projected onto the peripheral wall of the channel housing. In this way, when fluid pressure is applied to the diaphragm, the bulging deformation of the diaphragm will cause radial tensile deformation of the innermost piezoresistor in each strain gauge, while radial compressive deformation of the outermost piezoresistor will occur.

[0014] According to one embodiment of this utility model, the protrusion can be integrally formed with the diaphragm. In order to introduce as little stress as possible during the manufacturing process of the protrusion, it is preferable that the protrusion and the diaphragm are formed as a single piece.

[0015] According to a preferred embodiment of the present invention, the protrusion tapers tapering from the diaphragm. Here, the protrusion may have a frustoconical shape, thereby not hindering the diaphragm from bulging upwards under fluid pressure, and reducing stress concentration at the transition point of the protrusion onto the diaphragm, preventing accelerated metal aging at this location during repeated deformation of the diaphragm.

[0016] According to a particularly preferred embodiment of the present invention, the protrusion may have rounded corners at the transition point onto the diaphragm. This embodiment can further reduce stress concentration at the transition point of the protrusion onto the diaphragm, thereby improving the lifespan of the diaphragm and the sensing component.

[0017] According to a preferred embodiment of this invention, the thickness of the protrusion can be 1.5 to 3 times the thickness of the diaphragm. Simulation of the designed sensing element structure revealed that within this ratio range, the thickness of the protrusion relative to the diaphragm effectively avoids manufacturing defects associated with thinner diaphragms, and the geometry does not affect fluid pressure measurement. For example, a protrusion with a thickness of 0.3 to 0.6 mm, preferably around 0.3 mm, can be constructed on a diaphragm with a thickness of 0.2 mm.

[0018] According to one embodiment of this utility model, the diameter of the protrusion can be 1 / 2 to 1 / 4 of the diameter of the diaphragm. Specifically, the diameter ratio and area ratio of the protrusion to the diaphragm can be specifically designed within the above range according to the selected diaphragm size and strain gauge size.

[0019] According to one embodiment of the present invention, the protrusion can increase the slope of the radial stress sensed at the strain gauge along the radial direction. In simulations of the sensing element according to the present invention, it was unexpectedly discovered that, compared to a completely flat diaphragm, arranging a protrusion in the center of the diaphragm results in a more dramatic change in the radial stress sensed at the strain gauge along the radial direction, which additionally improves the sensitivity of the sensing component and the pressure sensor.

[0020] According to one embodiment of the present invention, the sensing component can be used to sense fluid pressures below 20 bar, particularly 10 bar or lower.

[0021] According to one embodiment of this utility model, the outer periphery of the channel housing may be constructed with a crimping portion, a welding portion, or a threaded portion. Here, in order to position and / or connect with the structural components of the pressure sensor, it is preferable to provide a mechanical connection portion, such as a crimping portion, a welding portion, or a threaded portion, on the outer periphery of the channel housing, particularly at the open end of the channel housing, so as to overlap, position, crimp, weld, especially laser weld, or threaded connection with the structural components of the pressure sensor.

[0022] According to one embodiment of this invention, a platform portion flush with the side of the diaphragm facing away from the fluid medium can be constructed around the peripheral wall of the channel housing. Here, the platform portion can have a thickness greater than that of the diaphragm to ensure the structural stability of the sensing component.

[0023] According to one embodiment of this utility model, the channel housing together with its diaphragm can be manufactured in one machining process. Preferably, subtractive processing, such as turning or boring, is used to gradually remove excess material from the blank to form a cylindrical cavity in the channel housing that is closed at one end by the diaphragm.

[0024] A second aspect of this invention relates to a pressure sensor for measuring fluid pressure, wherein the pressure sensor includes the sensing component for a pressure sensor described above.

[0025] It should be noted that the features, functions, effects, and advantages of one aspect of this utility model can also be referred to the above description of other aspects of this utility model. Furthermore, the various aspects described in this utility model can be combined with each other in various ways.

[0026] Other features of this invention are derived from the accompanying drawings and the detailed description. All features and combinations thereof mentioned above in the specification, as well as features and combinations thereof mentioned below in the detailed description and / or shown separately in the drawings, can be used not only in the corresponding combinations given, but also in other combinations, or in their individual states. Attached Figure Description

[0027] Figure 1 A cross-sectional view of a sensing component for a pressure sensor according to the prior art is shown;

[0028] Figure 2 A cross-sectional view of a sensing component for a pressure sensor according to an embodiment of the present invention is shown.

[0029] Figure 3a and Figure 3b Show each Figure 1 and Figure 2 The curves showing the variation of radial and tangential stresses of the diaphragm in the sensing component along the radial direction of the diaphragm are shown.

[0030] Figure 4a and Figure 4b Show each Figure 1 and Figure 2 The stress simulation diagram of the sensing component shown;

[0031] Figure 5a and Figure 5bShow each Figure 1 and Figure 2 The strain simulation diagram of the sensing component shown is shown. Detailed Implementation

[0032] Figure 1 and Figure 2 Cross-sectional views of a sensing assembly for a pressure sensor, according to both the prior art and an embodiment of the present invention, are shown in contrast. Figure 1 In, with Figure 2 Functionally identical parts or components are distinguished by reference numerals with an '.

[0033] like Figure 1 As shown, the sensing component 1' according to the prior art includes a channel housing 2' having a hollow cylindrical cavity 3', through which a fluid medium enters the channel housing 2' through an opening at the bottom. The fluid pressure of the fluid medium acts on a flat diaphragm 4' located above the channel housing 2' opposite to the opening, that is, on the fluid-facing side 4a' of the diaphragm 4', causing the diaphragm 4' to deform or bulge away from the fluid medium (pointing upwards in this case). This deformation of the diaphragm 4' can be sensed by a strain gauge (not shown) fixed to its fluid-facing side 4b'. In the sensing component 1' with this structural type, in order to measure fluid pressures in low pressure ranges, such as below 20 bar, especially 10 bar or lower, the diaphragm 4' needs to be designed to be very thin, for example, the thickness of the diaphragm 4' may be only 0.1 mm to 0.3 mm. Such a thin and flat diaphragm 4' will cause additional process problems during its processing and assembly, such as the diaphragm 4' being prone to bulging and deformation due to its thinness when sandblasting it; the strain gauge wire bonding failure on the diaphragm 4' without a strong support; and / or the residual thermal stress during the process of fixing the strain gauge to the diaphragm 4', which leads to an imbalance in the sensed resistance.

[0034] To overcome the manufacturing challenges caused by diaphragm thickness, the present invention proposes the following: The sensing component 1 for a pressure sensor includes a channel housing 2 with a hollow cylindrical cavity 3 for introducing a fluid medium. One end of the channel housing 2 is closed by a circular diaphragm 4 integrally formed with the channel housing 2. The diaphragm 4 can deform under the fluid pressure of the fluid medium. At least one strain gauge 8 is provided on the side 4b facing away from the fluid medium in the radial direction. Each strain gauge 8 includes at least two piezoresistors 8a and 8b extending in the radial direction. A circular protrusion 5 is centrally provided on the side 4a facing the fluid medium of the diaphragm 4.

[0035] like Figure 2As shown, the diaphragm 4 in the sensing component 1 according to this utility model is no longer as... Figure 1 As shown, the surface is flat. On the side 4a facing the fluid medium, a circular protrusion 5 is formed in the center of the diaphragm 4, protruding relative to the rest of the diaphragm 4. This can be understood as selectively thickening the portion of the diaphragm 4 that is not involved in fluid pressure measurement, while maintaining or even further reducing the relatively thin diaphragm thickness in the area involved in fluid pressure measurement. Thus, a thin annular region is formed around the protrusion 5, and this annular region is used to arrange the at least one strain gauge 8. This design achieves a sensing component structure suitable for measuring fluid pressures below 20 bar, particularly 10 bar or lower. Here, the protrusion 5 can serve as a reinforcing structure for the relatively thin diaphragm 4, enhancing its structural stability during sandblasting and wire bonding, preventing protrusion deformation during sandblasting and improving the yield of wire bonding, preventing residual thermal stress when the strain gauge is bonded to the diaphragm, especially by micro-melting technology, and reducing resistance imbalance sensed by the strain gauge, etc.

[0036] exist Figure 2 The diagram further illustrates a possible arrangement of strain gauges 8 on the side 4b of the diaphragm 4 facing away from the fluid medium. Here, the two strain gauges 8 are symmetrically distributed radially, i.e., opposite each other about the center of the diaphragm 4. It can also be seen that the two strain gauges 8 are positioned along a straight line on both sides of the protrusion 5. Each strain gauge 8 includes two piezoresistors 8a and 8b extending radially. The four piezoresistors on the diaphragm 4 can form a Wheatstone bridge, allowing the fluid pressure to be calculated based on the resistance values ​​of each piezoresistor. When fluid pressure is applied to the diaphragm 4, the deformation of the bulge in the diaphragm 4 causes a change in the resistance of one or more of these piezoresistors 8a and 8b. When a constant voltage is input to the four piezoresistors, the change in the resistance of one or more of the four piezoresistors will cause a corresponding change in at least one of the bridge output voltages. The change in output voltage can be used to calculate the deformation of the diaphragm 4 and the fluid pressure of the fluid medium.

[0037] Not limited to Figure 2As shown, two or more strain gauges 8 arranged radially around the center of the diaphragm 4 can also be positioned within the same radius. For example, two strain gauges 8 with the same center-to-center distance as the diaphragm 4 can be spaced apart by 90°, 120°, 160°, etc. Alternatively, three strain gauges 8 with the same center-to-center distance as the diaphragm 4 can be spaced apart by 120°. It is also possible to have only one strain gauge arranged radially, which includes four piezoresistors extending radially in pairs. In these alternative arrangements of strain gauges 8, every four piezoresistors on the diaphragm can also form a Wheatstone bridge, allowing the fluid pressure to be calculated based on the resistance values ​​of each piezoresistor.

[0038] Preferably, in the axial direction of the channel housing 2, the protrusion 5 can interact with the at least one strain gauge 8. Figure 2 The projected positions of the two strain gauges 8 do not coincide. That is, when viewed from the axial position of the channel housing 2, the protrusion 8 and each strain gauge 8 are misaligned with each other, i.e., spaced apart. Therefore, the protrusion 5 hardly affects the deformation of the position where the strain gauges 8 are fixed, and thus hardly affects the fluid pressure measurement.

[0039] Advantageously, in the axial direction of the channel housing 2, the at least one strain gauge 8 may partially coincide with the peripheral wall of the channel housing 2. Figure 2 As can be seen, the outer piezoresistor 8b of the two strain gauges 8 will partially project onto the peripheral wall of the channel housing 2. Thus, when fluid pressure is applied to the diaphragm 4, the bulging deformation of the diaphragm will cause the inner piezoresistor 8a of each strain gauge 8 to undergo radial tensile deformation, while the outer piezoresistor 8b will undergo radial compressive deformation.

[0040] In order to introduce as little stress as possible during the manufacturing process of the protrusion 5, it is preferably specified that the protrusion 5 can be integrally formed with the diaphragm 4, that is, it is a one-piece structure.

[0041] Advantageously, the shape of the protrusion 5 can be specified to taper from the diaphragm 4. For example, the protrusion 5 can have a shape similar to a frustoconical shape, thereby not hindering the diaphragm 4 from bulging under fluid pressure and reducing stress concentration at the location where the protrusion 5 transitions onto the diaphragm 4, preventing accelerated metal aging at this location during repeated deformation of the diaphragm 4.

[0042] To further reduce stress concentration at the transition point of the protrusion 5 onto the diaphragm 4, it is also preferred that the protrusion 4 be provided with rounded corners at the transition point onto the diaphragm 4.

[0043] in particular, Figure 2The sensing component 1 shown can be used to sense fluid pressures below 20 bar, particularly 10 bar or lower. For this purpose, it is particularly preferable that the thickness of the protrusion 5 is designed to be 1.5 to 3 times the thickness of the diaphragm 4. Within this ratio range, the thickness of the protrusion 4 and the diaphragm effectively avoids manufacturing defects associated with a thinner diaphragm and has almost no impact on fluid pressure measurement. For example, a protrusion 5 with a thickness of 0.3 mm to 0.6 mm can be constructed for a diaphragm 4 with a thickness of 0.2 mm. Alternatively or additionally, the diameter of the protrusion 5 can be specified as 1 / 2 to 1 / 4 of the diameter of the diaphragm 4.

[0044] In addition, Figure 2 The diagram also shows the structural design of the sensing component 1 for positioning and / or connection with the structural components of the pressure sensor. On one hand, a crimping portion 6, a welding portion, or a threaded portion can be constructed on the outer periphery of the channel housing 2. On the other hand, a platform portion 7, flush with the side 4b of the diaphragm 4 facing away from the fluid medium, can be constructed around the peripheral wall of the channel housing 2. Here, the platform portion 7 can have a thickness greater than that of the diaphragm to ensure the structural stability of the sensing component.

[0045] In terms of manufacturing, the channel housing 2 together with its diaphragm 4 can be manufactured in one machining process. Here, it is preferred to gradually remove excess material from the blank by subtractive machining, such as turning, boring and other machining methods, to form the cylindrical cavity 3 in the channel housing 2 that is closed at one end by the diaphragm 4.

[0046] It should also be noted that the sensing component 1 can also be called a port for the pressure sensor. It can be mechanically connected to the structural components of the pressure sensor (such as the housing, mounting structure, etc.) and electrically connected to the analysis circuit of the pressure sensor (such as the chip, etc.), thus forming a pressure sensor together.

[0047] Figure 3a and Figure 3b Show each Figure 1 and Figure 2 The curves showing the variation of radial and tangential stresses of the diaphragm in the sensing component along the radial direction of the diaphragm are illustrated. Figure 3a and Figure 3b In the graphs, the orange curve represents the variation of the radial stress of the diaphragm along the radial direction, and the blue curve represents the variation of the tangential stress along the radial direction. The origin of both graphs represents the center of the diaphragm, and each curve shows the numerical change of the corresponding stress from the center along the radial direction to both ends of the diaphragm. In these two graphs, the position of the inner varistor 8a in one of the strain gauges 8 is schematically represented by a red line segment on the horizontal axis, and the position of the outer varistor 8b in one of the strain gauges 8 is schematically represented by a green line segment.

[0048] from Figure 3a As can be seen, in the existing flat diaphragm 4', the maximum values ​​of radial and tangential stresses occur at the center of the diaphragm. However, due to the nonlinear change of the curve at the center, the strain gauge 8' does not sense the strain at this location, but is instead positioned further outward along the radial direction. Under fluid pressure, the inner piezoresistor 8a' of the strain gauge 8' on the diaphragm 4' bears radial tensile stress, while the outer piezoresistor 8b' bears radial compressive stress.

[0049] Since the central region of diaphragm 4' is not used in fluid pressure measurement, it is possible to specifically thicken diaphragm 4' in this central region to solve the aforementioned process issues. Through [further details needed]... Figure 3b As shown in the stress analysis chart, when a circular protrusion 5 is centrally located on the side 4a facing the fluid medium of the diaphragm 4, the maximum values ​​of radial and tangential stresses no longer appear at the center of the diaphragm. However, a linear change from positive to negative values ​​still occurs at the location where the strain gauge 8 is located. Therefore, the protrusion 5 according to this invention has almost no impact on the two principal stresses, radial stress and tangential stress, that cause deformation of the strain gauge 8. Thus, a series of manufacturing problems caused by the thinning of the diaphragm can be compensated for by locally thickened protrusions 5, without affecting the sensitivity of pressure measurement.

[0050] Especially through comparison Figure 3a and Figure 3b The simulation also reveals that, compared to Figure 1 The sensing component 1' with a flat diaphragm 4' in the prior art can also increase the slope of the radial stress sensed at the strain gauge 8 by providing a protrusion 5 for the diaphragm 4, thereby additionally improving the sensitivity of the sensing component 1 and the pressure sensor, and optimizing the sensitivity of fluid pressure measurement while solving process problems.

[0051] Figure 4a and Figure 4b Show each Figure 1 and Figure 2 The stress simulation diagram of the sensing component shown is illustrated. It can be seen that in the sensing component 1 according to this invention, the stress in the central region of the diaphragm 4 is no longer the maximum, but the stress based on fluid pressure is concentrated in the annular region surrounding the boss where the strain gauge 8 can be installed.

[0052] Figure 5a and Figure 5b Show each Figure 1 and Figure 2 The figure shows a strain simulation diagram of the sensing component. From this diagram, it can be seen that... Figure 2 The strain in the central region of the diaphragm 4 with protrusions 5 decreased significantly overall.

[0053] This invention is not limited to the embodiments shown, but includes or extends to all technical equivalents that fall within the scope of the appended claims. The positions chosen in the specification, such as above, below, left, right, etc., refer to the direct description and the accompanying drawings, and can be adapted to new positions according to their meaning when the positions change. Furthermore, it should be noted that the various drawings of this invention are schematic and may not be shown to scale.

[0054] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

Claims

1. A sensing assembly for a pressure sensor, the sensing assembly (1) comprising a channel housing (2) having a hollow cylindrical cavity (3) for introducing a fluid medium, the channel housing (2) being closed at one end by a circular diaphragm (4) integrally formed with the channel housing (2), the diaphragm (4) being deformable under the fluid pressure of the fluid medium, the diaphragm (4) having at least one strain gauge (8) arranged radially on a side (4b) opposite to the fluid medium, each strain gauge (8) comprising at least two piezoresistors (8a, 8b) extending radially, characterized in that, The diaphragm has a circular protrusion (5) centrally located on the side (4a) facing the fluid medium.

2. The sensing component according to claim 1, characterized in that, In the axial direction of the channel housing (2), the projection position of the protrusion (5) does not coincide with that of the at least one strain gauge (8).

3. The sensing component according to claim 2, characterized in that, In the axial direction of the channel housing (2), at least one strain gauge (8) partially coincides with the peripheral wall of the channel housing (2).

4. The sensing component according to any one of claims 1 to 3, characterized in that, The protrusion (5) is integrally formed with the diaphragm (4).

5. The sensing component according to claim 4, characterized in that, The protrusion (5) tapers tapering from the diaphragm (4).

6. The sensing component according to claim 4, characterized in that, The protrusion (5) has rounded corners at the position where it transitions to the diaphragm (4).

7. The sensing component according to any one of claims 1 to 3, characterized in that, The thickness of the protrusion (5) is 1.5 to 3 times the thickness of the diaphragm (4).

8. The sensing component according to any one of claims 1 to 3, characterized in that, The diameter of the protrusion (5) is 1 / 2 to 1 / 4 of the diameter of the diaphragm (4).

9. The sensing component according to any one of claims 1 to 3, characterized in that, The protrusion (5) increases the slope of the radial stress sensed at the strain gauge (8) as it changes in the radial direction.

10. The sensing component according to any one of claims 1 to 3, characterized in that, The sensing component (1) is used to sense fluid pressure below 20 bar.

11. The sensing component according to any one of claims 1 to 3, characterized in that, The outer periphery of the channel housing (2) has a press-fit part (6), a welded part, or a threaded part.

12. The sensing component according to any one of claims 1 to 3, characterized in that, The peripheral wall of the channel housing (2) has a platform portion (7) that is flush with the side (4b) of the diaphragm (4) facing away from the fluid medium.

13. The sensing component according to any one of claims 1 to 3, characterized in that, The channel housing (2) together with its diaphragm (4) is manufactured in one process by machining.

14. A pressure sensor for measuring fluid pressure, characterized in that, The pressure sensor includes a sensing component for a pressure sensor as described in any one of claims 1 to 13.

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