EP3555584A1

EP3555584A1 - Method for producing a pressure sensor measuring element and thus obtained pressure sensor measuring element

Info

Publication number: EP3555584A1
Application number: EP17825405.8A
Authority: EP
Inventors: Ulrich Staiger; Daniel Stark; Achim Pahlke; Dieter Zeisel
Original assignee: TRAFAG AG
Current assignee: TRAFAG AG
Priority date: 2016-12-14
Filing date: 2017-12-07
Publication date: 2019-10-23
Also published as: US20190360894A1; US11137320B2; WO2018108710A1; CN110476046B; CN110476046A; DE102016124410A1

Abstract

The aim of the invention is to economically produce a pressure measuring sensor element, and relates, according to one aspect, to a method for producing a pressure sensor measuring element for a pressure sensor which comprises at least one membrane and a covering protecting the membrane, the pressure sensor element being produced in a layer-by-layer generative production method. This makes it possible to, for example, easily construct a combi-sensor for detecting pressure and an additional parameter. It is also possible to structures for reinforcement or for influencing resonant frequency or for influencing heat conduction.

Description

METHOD FOR MANUFACTURING A PRESSURE SENSOR ELEMENT AND THEREFORE AVAILABLE PRESSURE SENSOR ELEMENT

The invention relates to a method for producing a

Pressure sensor, as known in particular from WO 2010/149501 A1. Moreover, the invention relates to a pressure sensor measuring element obtainable by such a method and to a pressure sensor measuring element provided therewith

Pressure sensor.

WO 2010/149501 A1 describes a pressure sensor measuring element and a pressure sensor provided therewith for pressure detection in a combustion chamber of an internal combustion engine during its operation. For this has the

Pressure sensor measuring a separation membrane, a plunger for transmitting deflections of the separation membrane on a force measuring element and the plunger receiving sleeve, wherein the separation membrane and the plunger is integrally formed as a membrane-plunger unit. A pressure measurement in the combustion chamber of the internal combustion engine takes place while shielding the force measuring sensor from the conditions prevailing in the combustion chamber. For the production of

Drucksensormesselements the sleeve and the separation membrane ram unit are each made separately by turning or by other machining processes of a monolithic stainless steel, then interlocked and connected by means of welded joints. For this purpose, edge regions of a first membrane facing the combustion chamber and a second membrane arranged facing away from the combustion chamber are connected by welding to corresponding edges of the sleeve. This will be a

Pressure measuring element created that combines high accuracy with low temperature dependence and a small number of parts. Due to the metal as a material, heat can be easily dissipated. Based on the prior art according to WO 2010/149501 A1, the invention has for its object to be in terms of manufacturability and / or

To provide a functional scope improved pressure sensor measuring element.

To achieve this object, the invention provides a method according to claim 1. A pressure sensor measuring element which can be produced thereby and a pressure sensor provided therewith are specified in the dependent claims.

Advantageous embodiments are the subject of the dependent claims.

According to a first aspect, the invention provides a method for producing a pressure sensor element for a pressure sensor, which has at least one membrane and a sleeve supporting the membrane, wherein the

Pressure sensor measuring element in a layerwise generative

Manufacturing process is produced.

It is preferred that the generative manufacturing process

A metal powder layer method is that in which metal powder is layered and selectively deformed with a laser or electron beam

computer controlled selectively over a powder layer is moved to

solidify selected areas.

It is preferable that such a metal powder is used and that

Solidification is carried out such that the pressure sensor measuring element of a

Steel material, a stainless steel material and / or a NiCrNbMo alloy (in particular made of a material with the material number 2.4668, such as Inconel 718).

In a preferred embodiment with the generative manufacturing process is integrally a separation membrane, a plunger for transmitting

Deflections of the separation membrane on a force measuring element and a sleeve receiving the plunger and a sleeve on the separation membrane

opposite side final another membrane made. It is preferred that the generative manufacturing method at least one channel or a decoupling structure for decoupling the membrane or the sleeve of internal structures of the pressure sensor and / or passing through the pressure sensor measuring channel for at least one connection or signal line and / or by the pressure sensor measuring element leading signal or connection line and / or at least one

Stiffening structure for influencing a bending characteristic and / or a resonance frequency and / or at least part of an electronic

Component, such as in particular an electrical resistance and / or at least one transverse structure and / or at least one heat shield is made.

It is the attachment of at least one sensor element for measuring a further parameter in the region of the membrane and / or the sleeve and

Contacting the sensor element by means of the signal or connecting line preferred.

It is preferred that the at least one sensor element is selected from a temperature sensor element for measuring a temperature, a

Temperature difference measuring element for detecting a temperature difference between the membrane and a region of the sleeve facing away from the membrane, a membrane structure monitoring element for monitoring the

Membrane structure and a resistance element for detecting an electrical resistance of at least a portion of the membrane.

In a preferred embodiment, the method is characterized

Surface finishing at least on the membrane.

It is preferred that at least one powder outlet opening for removing powder material from a cavity of the fabricated by the additive manufacturing process structure is introduced and the powder is removed through the at least one powder outlet opening and the at least one powder outlet opening is closed. In an alternative embodiment it is preferred that the powder material is retained in a cavity of the structure fabricated by the additive manufacturing process.

In another aspect, the invention provides a

Pressure sensor measuring element, comprising:

at least one membrane and a sleeve for supporting the membrane and at least one sensor element for measuring a further parameter in

Area of the membrane.

The pressure sensor measuring element is produced in particular by a method according to one of the previously explained embodiments or can be produced therewith.

Preferably, the pressure sensor measuring element is designed for a pressure sensor for pressure detection in a combustion chamber of an internal combustion engine during operation, wherein the membrane is a separation membrane, wherein a plunger for transmitting deflections of the separation membrane to a

Force measuring element is provided, wherein the sleeve receives the plunger and a the combustion chamber to be turned first end through the separation membrane is closed and formed at the opposite second end for holding the force-measuring element, wherein the plunger, the diaphragm and the sleeve are integrally formed.

Preferably, the pressure sensor measuring element has at least one stiffening structure for stiffening against deformation or for influencing

Resonant frequencies.

Preferably, the pressure sensor measuring element has at least one rib or a projection or a ring.

Preferably, the pressure sensor measuring element has transverse structures in the form of one or more heat shields.

Preferably, the pressure sensor measuring element has at least one channel for

Performing at least one line or decoupling an inner structure and an outer structure.

Preferably, the pressure sensor measuring element has at least one cavity between an inner and an outer structure.

Preferably, the pressure sensor measuring element has at least one sensor element for monitoring the function or the structure of the membrane.

Preferably, the pressure sensor gauge is made of steel, stainless steel or NiCrNbMo alloy (e.g., Inconel 718).

According to a further aspect, the invention provides a pressure sensor comprising a pressure sensor measuring element according to one of the preceding

Configurations.

Preferably, the pressure sensor is a combination sensor for detecting both pressure and temperature. According to a further aspect, the invention provides a pressure sensor measuring element for a pressure sensor for pressure detection in a combustion chamber of a

Internal combustion engine during its operation, wherein the membrane is a separation membrane, wherein a plunger for transmitting deflections of the separation membrane is provided on a force measuring element, wherein the sleeve receives the plunger and a one of the combustion chamber to be turned first end is closed by the separation membrane and at the opposite second end for holding the force-measuring element is formed, wherein the plunger, the diaphragm and the sleeve are integrally formed.

The following are some of the most preferred benefits

Embodiments of the invention explained in more detail.

In particular, in pressure sensors used in combustion chambers but also in other pressure sensors would often be in addition to the pressure measurement

Temperature measurement desirable.

However, the high pressures and temperatures in a combustion chamber or other media to be measured results in an attempt to minimize the number of connections to the outside of the combustion chamber or to

provide measuring pressure chamber. A reduction in the number of

Sealing points is the goal in the construction of internal combustion engines or other systems to be monitored.

In previously used pressure sensor measuring elements, the production of special progressions of channels, in particular a central bore or the like, is difficult. Such a central bore is difficult to produce by machining techniques with machining processes.

With the generative manufacturing method to be used according to the invention, very different and even complex shapes can be produced relatively easily. Thus, structures for different additional functions can be easily implemented. In particular, channels or the like can now be easily produced, so that it is now relatively easy to To accommodate additional sensor elements in the pressure sensor measuring element for measuring further parameters in the region of the front membrane and to contact through channels or lines from behind.

Embodiments of the invention are explained below with reference to the accompanying drawings. It shows:

Fig. 1 is a schematic representation of a manufacturing apparatus for

Performing an additive manufacturing process in the course of manufacturing a pressure sensor element according to an embodiment;

Fig. 2 is a schematic diagram of a preferred application of the disclosed herein

Pressure sensor measuring element;

3 is a perspective view of a pressure sensor element according to a first embodiment;

4 is a sectional view of the pressure sensor element according to the first

embodiment;

5 is another sectional view of the pressure sensor element according to the first embodiment;

6 shows a further sectional view of the pressure sensor element with an inserted sensor element according to the first embodiment;

Fig. 7 is a plan view of the pressure sensor element shown in Fig. 5;

Fig. 8 is a further sectional view of the pressure sensor element with

unclosed powder outlet openings according to the first

embodiment; 9 is a perspective view of the pressure sensor hub according to the first embodiment;

10 is a sectional view of the pressure sensor element according to a second embodiment;

FIG. 11 is a perspective sectional view of the pressure sensor element according to the second embodiment; FIG.

12 shows a perspective sectional view of a pressure sensor element with structural elements on the inner wall of the sleeve; and

Fig. 13 is a further perspective sectional view of a

Pressure sensor with structural elements on the inner wall of the sleeve and outer wall of the plunger

In the following, reference is first made to Fig. 1, to a

To explain manufacturing method for manufacturing a pressure sensor element. In the manufacturing process, a generative manufacturing process is used. In the generative manufacturing process described herein, a control system 56, e.g. as a software file existing model of a

Pressure sensing sensor element physically without the need for special tools and forming equipment by selective solidification of powder material 21, in particular metal powder 22, which is located in a layer 32 in a powder bed 24 generates.

Fig. 1 shows a manufacturing apparatus 10 for carrying out the additive manufacturing process for producing the pressure sensor element. The

Manufacturing apparatus 10 has a process space 12, a

Material supply device 14 for the layered provision of material to be processed, for example from a powder reservoir 18, a

Beam generating device 36 for generating a processing radiation 42 and the control system 56 on. In the process space 12 there is the powder bed 24, which has a movable powder bed bottom 26, which is moved down after processing a layer 32 by the corresponding processed layer thickness of the respective last passage. At the beginning of the manufacturing process is the

Powder bed 26 preferably at an upper position 28th

The material supply device 14 has a powder application device 20, which is designed in particular such that, after the processing of a layer 32, a new layer 32 to be processed from the powder supply 18 is applied to the powder bed 24 again. The

Powder applicator 20 may be, for example, a Schichtverteilschieber 30 or a filling device 16. During the irradiation process by the beam generating device 36, the layer distribution slide 30 is in the waiting position in the area of the material supply device 14 which is not located in the machining radiation area. The Schichtverteilschieber 30 is only one example of the powder applicator 20, it can also more

Powder applicators are used, such. Powder nozzles for selective powder application, etc. In the powder bed 24 is formed in layers that the workpiece to be generated 34th

The beam generating device 36 has a beam generating unit 38 and at least one beam influencing device 46.

The beam generating unit 38 generates a processing radiation 42 sufficient for the processing, for example, the processing radiation 42 may be a laser or electron beam. Optionally, the

Beam generating device 36, an optical fiber 40 for directing a

Laser beam trained machining radiation 42.

The beam influencing device 46 is in particular for steering,

Focusing or otherwise influencing the processing radiation formed. For this purpose, the beam influencing device 46 has, for example, a lens 44, and the beam influencing device 46 leads, for example

Focusing movements 48 through. The beam generating device 38 can in a plane by means of a beam generating unit-moving device 62 are moved by the control system 56 and beam generating unit-Verfahrbewegungen 64 perform.

The process space 12 is separated from the environment by a protection device 50. The protective device can be designed for example by a transparent to laser radiation protection plate 52 made of glass or other materials.

The control system 56 in particular allows the beam generating device 36 to be moved in such a way that certain areas of the material layer 32 to be processed are irradiated in order to form the material at the required areas, for example in the radiation impingement 54 (eg fuse or sinter the powder) and to form the workpiece 34 , After processing all areas relevant to the layer to be processed, the powder bed bottom 26 is moved downwards and the powder application device 20 applies a new material layer for renewed selective irradiation via the previously processed layer 32. For example, this can be done by the

Schichtverteilschieber 30 moves over the powder bed 24. The control system 56 can be a data processing system 58, for example a CAD system or similar system, which is connected to the units to be controlled

Manufacturing device 10 is connected via a control line 60.

In particular, a steel material, a stainless steel material and / or a NiCrNbMo alloy (e.g., Inconel 718) is suitable as the powder material 22, the latter materials having particular advantages in corrosion resistance. Sensors made of such material are used, for example

Used marine diesel engines. In it, fuel oils or the like are burned for cost reasons. If heavy oils are burned in cold engines, residues are created which are particularly problematic with regard to corrosion of the engine components.

Exemplary embodiments of generative manufacturing methods suitable for the production of the pressure sensor armature can be Selective Laser Sintering, Laminated Object Manufacturing, Fused Deposition Modeling, Solid Ground Curing, and SD Print-Like Procedures.

With the manufacturing apparatus 10 can thus layer by layer as a workpiece

Druckensormesselennent 66 are produced, which will be explained in more detail below with reference to the remaining figures.

FIG. 2 shows a preferred application of the pressure sensor element 66.

As can be seen in FIG. 2, the pressure sensor measuring element 66 has a first end 70 and a second end 72. The pressure sensor measuring element 66 is brought into direct connection with the first end 70 with a measuring space 74. The measuring space 74 may, for example, a combustion chamber 76 of a

Be internal combustion engine. For example, therefore, the first end 70, a combustion chamber facing side and the second end 72 a

be away from the combustion chamber.

The pressure sensor measuring element 66 is designed in particular for monitoring the combustion chamber of an internal combustion engine, such as a

Marine engine (powered, for example, by heavy fuel oil or diesel),

Diesel engines for construction machinery and motor vehicles, or a gasoline engine for motor vehicles and the like, as well as in areas of

High-temperature applications such as the monitoring of turbines, for example, the pressure measurement within a hot steam turbine and injection molding machines.

Likewise, such pressure measuring sensor elements 66 are also suitable for

Measurements on corrosive media such as these, including in the

Process technology in chemistry occur.

With the pressure sensor measuring element 66 thus a pressure 84 online in the operation of a system or machine to be monitored, in particular a

Combustion chamber pressure can be measured online during operation of the internal combustion engine. Based on the pressure signal controls and

Regulations for the operation of the machine such as internal combustion engine can be performed, and it can be the operation and the function of the machine such as in particular internal combustion engine monitored. By

expedient positioning of further sensor elements 122 in the

Pressure sensing element 66, which will be explained in more detail later in the description, it is also possible, pressure and temperature differences

issue. For this purpose, for example, a temperature difference 82 between the first end 70 and the second end 72 of the pressure measuring element 66 is detected. Likewise, for example, a temperature difference measuring element can be used for this purpose. As a result, a sensor can be obtained, the one

Temperature passage and / or temperature line detected.

Referring to Figs. 3 to 5, an embodiment of the

Pressure sensor 66 described which can be produced with the manufacturing apparatus 10 previously described with reference to FIG.

As can be seen from FIGS. 3 to 5, the pressure measuring element 66 has a

Pressure measuring cell 68 and a force measuring element 88. The pressure measuring cell 68 is manufactured in one piece in the additive manufacturing process.

The pressure measuring cell 68 has a membrane plunger unit 1 14 and a sleeve 94. The membrane plunger unit 1 14 has a first membrane or

Measuring diaphragm, which faces the measuring space 74, in the form of a

Separation membrane 92, which is connected by means of a plunger 108 with a second, the measuring space 74 facing away from membrane 1 12 such that

Movements of the separation membrane 92 are transferred to the second membrane 1 12. The membrane 92, 1 12, the plunger 108 form the membrane ram unit 1 14, which is housed within the sleeve 94. The sleeve 94 is not reworked in one embodiment.

The force measuring element 88 is in particular as a bending beam 90 with

Strain gauge formed.

The sleeve 94 is, as shown in Fig. 3 can be seen, formed substantially cylindrical. At the first end 70, the sleeve 94 has at its outer periphery a radially extending flange 86, which terminates flush in the region of the separating membrane 92. The separation membrane 92 can be influenced in its membrane properties by structuring or changes to the geometry. The flange 86 is not reworked in one embodiment.

The pressure measuring cell 68 will be described in more detail below with reference to FIGS. 4 and 5. The pressure measuring cell 68 has only one component or part, namely the one-piece unit of the sleeve 94, the separation membrane 92, the plunger 108 and the membrane 1 12 at the second end 72. The sleeve 94 and the plunger 108 have in the inner region between a Outside wall 1 10 of the plunger 108 and an inner wall 106 of the sleeve 94 has a smooth surface. The pressure measuring cell 68 is manufactured by the generative manufacturing method. At the second end 72 of the pressure measuring cell 68 of the bending beam 90 is attached to the second membrane 1 12.

In the production of the pressure measuring cell 68 remains by the generative

Manufacturing process unprocessed, loose powder material 22 in the cavity 104 between plunger 108 and inner wall 106 of the sleeve, wherein the at least one powder outlet opening 96 due to the making of the tightness of

Pressure measuring cell 68, after the loose material powder 22 has been removed, are closed, for example, by a closure ring 98. The at least one powder outlet opening 96 should be sufficient

Diameter, so that the material powder can be completely removed. The closure ring 98 is applied to close the powder outlet opening 96 and, as shown in Fig. 4, welded at two annular welds 100 with the sleeve 94 and the membrane 1 12 at the second end 72 of the pressure measuring cell 68. The welding process may be, for example

Be laser welding. For this purpose, the pressure measuring cell 68 in the region of the second end 72 has an axially extending shoulder 102 with a smaller diameter than the sleeve. On this

Locking ring shoulder 102, the locking ring 98 is pushed. In the region of the first end 70, the separation membrane 92 in the outer radial circumference in the annular membrane region 1 18 in the wall of the sleeve 94 via. In the membrane 1 12 at the second end 72, it behaves analogously.

Within the plunger 108, a channel 120 is provided which extends from the first end to the second end of the pressure measuring cell 68 and in the

at least one further sensor element 122 can be inserted. The

Sensor element 122 may, for example, a resistance sensor or a

Be temperature sensor.

The sectional view partially structural elements 136 are shown. The structural elements 136 are arranged on the inner wall of the sleeve 106 radially on the entire circumference and extend axially. Size, number and

The design of the structural elements 136 are illustrated by way of example in all figures and can vary depending on the necessity of influencing the respective parameter. The structural elements 136 serve to influence different parameters such as, for example, the rigidity, temperature conduction and the resonance frequency and can be mounted, for example, in the form of ribs 138 on the respective component.

FIG. 5 shows a different sectional plane from that shown in FIG. 4, from which it can be seen that the channel 120 extends to the first end 70 of the pressure measuring cell 68 and at least one opening 132 for carrying out a further sensor, i.

in particular the temperature sensor is suitable. The opening 132 is reworked in one embodiment, for example drilled to a diameter of 0.2 mm.

FIG. 6 shows the same sectional plane as FIG. 5. In contrast to FIG. 5, the additional sensor element 122 is now inserted into the channel 120 of the plunger 108 of the pressure measuring cell 68 in FIG.

In a separating membrane-ram transition region 1 16, the at least one opening 132 can be seen, in which at least one sensor tip 130 of the additional sensor element 122 is positioned. The sensor tip 130 is flush with the separation membrane 92.

The production of the tightness can be done by connecting the sensor tip 130 and separation membrane 92, for example by welding.

The sensor tip 130 is thus positioned near the measuring space 74, which may represent, for example, the combustion chamber temperature TB 78 of the combustion chamber 76.

On the other hand, the sensor element 122 also the review of

Surface structure of the separation membrane 92 serve. Furthermore, elements can be attached to the membrane for monitoring the membrane structure or the function of the separation membrane 92. An example is the attachment of a resistor to the inside of the separation membrane 92. This allows cracks in the

Monitor separation membrane 92. If a crack occurs on the separating membrane 92, the electrical resistance changes.

In making such a resistor, one could proceed so that, if the corresponding layer were to be built, another powder material would be applied to the material for resistance

provide.

Fig. 7 shows a plan view of the pressure measuring cell 68. In the center are the

Openings for insertion 132 of the additional sensor element 122 and an associated signal line 124 or connecting line 126 can be seen. The conduits 124, 126 may be routed out of the pressure sensing cell 68 at the second end 72 through conduit passages 128 to processing electronics (not shown).

8 and 9 show the state of manufacture of the pressure measuring cell 68 after manufacture, after the powder material 22 through the at least one

Powder exit port 96 has been removed. The powder outlet opening 96 is arranged in the region of the second end 72. A second embodiment is shown in FIG. In contrast to the first embodiment described so far no powder outlet openings 96 are present in these embodiments, and the material powder 22 remains in the pressure measuring cell 68. In this way, in particular the

Temperature passage can be influenced.

Fig. 1 1 shows a section in the region of the flange 86. The pressure measuring cell 68 may have further transverse structures. To reduce the effect of heat from the combustion chamber side facing the side facing away from the combustion chamber, the flange 86 has a heat shield 134 inside the pressure measuring cell. These

Structures ensure a lower heat conduction from the

side facing the combustion chamber to the combustion chamber side facing away. For this example, a FEM calculation for the heat transfer calculation can be created. The introduction of such structures is possible in the production of a generative manufacturing process. In the center of the pressure measuring cell 68, the channel 120 is arranged.

Further embodiments of the structural elements 136 of sleeve 94 and plunger 108 can be seen in FIGS. 12 and 13. For better representation is the

Pressure measuring cell 68 cut in the region between the first end 70 and the second end 72, wherein the structural elements 136 in FIGS. 12 and 13

are exemplified as stiffening ribs 138. Other possibilities include the provision of channels in the wall or the

Production of further axial decoupling geometries. Thus, the outer shell, which is more mechanically stressed, mechanically decoupled from the inner structure. With such stiffening ribs 136 can be

especially affect resonance frequencies. That's how one can be

Resonance frequency, which would be in the first drawing without stiffening ribs at about 7 kilohertz, in the range of 20 kilohertz or above. Analogous to the descriptions in FIG. 12, the plunger in FIG. 13 has further ribs 138.

The interior of the pressure measuring cell 68 should be tight to prevent penetration of the combustion gas into the pressure measuring cell when the separation membrane 92 fails to prevent. Therefore, in a preferred embodiment, the at least one powder outlet opening 96 is closed with a powder outlet opening closure ring 98. The powder discharge port lock ring 98 becomes

tightly welded, for example with a laser welding process.

Especially when using stainless steel, the stainless steel grades with the material numbers 1 .4542 and 1 .4548 are suitable for use in one

Pressure sensor measuring element.

An important aspect of the invention relates to the combination of at least two sensors. This creates a combination sensor, which pressure and

Temperature measures.

Therefore, pressure and temperature at the separation membrane 92 can be measured. It is also possible to output pressure and temperature difference. For this purpose, a temperature difference between the membrane side and the back is detected. As a result, a sensor can be obtained, the one

Temperature passage or temperature line detected.

The generative manufacturing process offers particular advantages in the

Explained below.

Here, the choice of materials (in particular Inconel 718 - this material has particular advantages in terms of corrosion resistance) to call. Of the

Background is that such sensors are used for example in marine diesel; It is burned for cost reasons heavy oils or the like. If heavy oils are burned in cold engines, residues arise that are particularly problematic with respect to corrosion of the

Engine components are.

Another advantage of the invention makes reference to the shape of a

Pressure sensor. A particular difficulty of this type of pressure sensors is the production of special runs of channels, in particular a central bore. Such a central bore is manufacturing technology with cutting Process more difficult to produce. For this is the generative

Forming process predestined.

Another possibility is, channels for lines, especially one

Thermocouple or the like produce.

Another possibility is to produce, for example, in the wall channels or axial decoupling geometries. So the outer shell, the more

is mechanically stressed, mechanically decoupled from the internal structure.

It can attach more structures. An example are stiffening ribs. These are shown in the already explained figures as an example. With such stiffening ribs in particular resonance frequencies can be influenced. Thus, a resonance frequency, which in the first drawing without stiffening ribs would be about 7 kilohertz, can be in the range of 20

Kilohertz or above.

Furthermore, elements can be attached to the separation membrane 92 for monitoring the membrane structure or the function of the separation membrane 92. An example is the attachment of a resistor to the inside of the separation membrane 92. This allows cracks in the separation membrane 92 to be monitored. If a crack occurs on the separating membrane 92, the electrical resistance changes.

The manufacturing process is then such that, if the corresponding layer were to be built, a different powder material would be applied to provide the material for the resistor.

Another example would be the arrangement of cross structures, such as the heat shield 134. Here, one may use an FEM calculation for the

Create heat transfer. The membrane is arranged for example in a combustion chamber of an engine; here it is, the temperature of the electronics

keep. With the generative production technology you can accordingly Introduce structures that provide less heat conduction from the hot side to the cold side.

In the second embodiment with powder discharge openings, it has been found that the powder discharge holes 96 should have a sufficiently large diameter so that the powder can be completely removed. These can then be closed by a closing element - for example, the powder outlet opening-locking ring 98.

Another alternative embodiment involves leaving the powder material 21 in the sensor.

Possible applications are mainly planned for

High-temperature applications such as combustion chamber monitoring, however, also for injection molding machines and the monitoring of turbines such as a hot steam turbine, in which case the pressure is measured, for example, within the turbine. Likewise, measurements on corrosive media are conceivable, as occur, for example, in process technology in chemistry.

In the following section, the surface finishing will be discussed in more detail. The surfaces are quite rough in generative manufacturing processes. At the points where high surface finish or high flatness is desired, post-processing steps are provided. Currently, this is being considered for the

Separation membrane 92 and those places where force elements must be welded.

At the separation membrane 92, other post-processing steps can be performed. The membrane thickness of the separation membrane 92 should be maintained.

For example, if post-processing is planned on the separation membrane 92, structuring of the separation membrane 92 may also be performed. An example is that from the outside towards the middle a slight angle is set back can be introduced to the force element in the membrane to the

To improve membrane properties.

For more details on the structure, the advantageous use and operation of the pressure sensor and a sensor therewith

Pressure sensor is expressly referred to WO2010 / 149501 A1, which is incorporated herein by reference. Further details of advantageous embodiments of the invention result from a combination of measures, steps, features and technologies described herein with the disclosure of WO 2010/149501 A1.

In order to produce pressure measuring sensor elements cost-effectively, the invention according to one aspect thereof provides a method for producing a pressure sensor element for a pressure sensor, which has at least one membrane and a sleeve supporting the membrane, wherein the

Pressure sensor measuring element in a layerwise generative

Manufacturing process is produced. This makes it easy to set up, for example, a combination sensor for detecting pressure and another parameter. In addition, structures for stiffening or resonance frequency influencing or for influencing heat conduction can be introduced.

LIST OF REFERENCE NUMBERS

10 manufacturing device

12 process room

14 material supply device

16 filling device

18 powder supply

20 powder applicator

21 powder material

22 metal powder

24 powder bed

26 powder bed floor

28 upper position of the powder bed floor

30 shift valve

32 shift

34 workpiece

36 beam generating device

38 beam generating unit

40 optical fiber

42 processing radiation

44 lens

46 beam influencing device

48 focusing movement

50 protection device

52 protective screen

54 radiation impact point

56 control system

58 data processing system

60 control line

62 Beam generation unit moving device

64 beam generating unit travel movement

66 pressure sensor measuring element

68 pressure measuring cell

70 first end

72 second end 74 measuring room

76 combustion chamber

78 combustion chamber temperature TB

82 temperature difference ΔΤ

84 pressure

86 flange

88 force measuring element

90 bending beams

92 separating membrane (facing the combustion chamber)

94 sleeve

96 powder outlet opening

98 powder outlet opening lock ring

100 locking ring weld

102 lockring heel

104 cavity

106 inner wall of the sleeve

108 pestles

1 10 outer wall of the ram

1 12 membrane (away from the combustion chamber)

1 14 diaphragm ram unit

1 16 Separating diaphragm ram transition area

1 18 ring membrane area

120 channel

122 sensor element

124 signal line

126 connecting cable

128 line passage opening

130 sensor tip

132 Opening for sensor

134 heat shield

136 structural element

138 rib

Claims

Claims:

1 . A method of manufacturing a pressure sensing element (66) for a pressure sensor comprising at least one diaphragm (92) and a sleeve (94) supporting the diaphragm (92), wherein the pressure sensing element (66) is fabricated in a layered additive manufacturing process.

2. The method according to claim 1,

characterized,

in that the additive manufacturing process is a metal powder layer process in which metal powder (22) is applied in layers and selectively deformed with a laser or electron beam which is computer controlled selectively over a powder layer (32) to solidify selected regions.

3. The method according to claim 2,

characterized,

that such a metal powder (22) is used and the solidification is such that the pressure sensor measuring element (66) is made of a steel material, a stainless steel material and / or a NiCrNbMo alloy.

4. Method according to one of the preceding claims,

characterized,

in that integrally with the generative manufacturing process, a separation membrane (92), a plunger (108) for transmitting deflections of the separation membrane (92) on a force measuring element (88) and a sleeve (94) receiving the plunger (108) and a sleeve (94 ) on the separation membrane (92) opposite side final additional membrane (1 12) is made.

5. The method according to any one of the preceding claims, characterized,

that is manufactured using the generative manufacturing process:

a) at least one channel (120) or a decoupling structure for

Decoupling the diaphragm (92) or sleeve (94) from internal structures of the pressure sensing element (66); and or

b) a through the pressure sensor measuring element (66) passing channel (120) for at least one connecting line (126) or signal line (124) and / or

c) a signal line (124) or connecting line (126) leading through the pressure sensor measuring element (66) and / or

d) at least one stiffening structure for influencing a

Bending characteristic and / or a resonant frequency and / or

e) at least a part of an electronic component, such as in particular an electrical resistance

f) at least one transverse structure

g) at least one heat shield (134).

6. The method according to claim 5,

marked by

Attaching at least one sensor element (122) for measuring a further parameter in the region of the membrane (92) and / or the sleeve (94) and

Contacting the sensor element (122) by means of the signal line (124) or connecting line (126).

7. The method according to claim 6,

characterized,

the at least one sensor element (122) is selected from a temperature sensor element for measuring a temperature (78), a

A temperature difference sensing element for sensing a temperature difference (82) between the diaphragm (92) and a portion of the sleeve (94) remote from the diaphragm, a diaphragm structure monitoring element for monitoring the diaphragm structure, and a resistance element for sensing electrical resistance of at least a portion of the diaphragm (92).

8. Method according to one of the preceding claims,

characterized by surface finishing at least on the membrane (92).

9. Method according to one of the preceding claims,

characterized by steps 9.1 .1 and 9.1 .2:

9.1 .1 introducing at least one powder outlet opening (96) for removing powder material (21) from a cavity (104) with the generative

Manufacturing process manufactured structure and

9.1 .2 removing the powder (21) by the at least one

Powder outlet opening (96),

or by steps 9.1 .1 and 9.1 .2 and step 9.1 .3:

9.1 .3 Closing the at least one powder outlet opening (96)

or by the step:

9.2 maintaining powder material (21) in a cavity (104) of the structure made by the additive manufacturing process.

A pressure sensor gauge obtainable by a method according to any one of the preceding claims, comprising:

at least one membrane (92) and a sleeve (94) for supporting the membrane (92) and at least one sensor element (122) for measuring a further parameter in the region of the membrane (92).

1 1. Pressure sensor measuring element according to claim 10,

characterized,

the at least one sensor element (122) is selected from a

Temperature sensor element for measuring a temperature, a

Temperature difference measuring element for detecting a temperature difference (82) between the membrane (92) and a region of the sleeve (94) facing away from the membrane (92), a membrane structure monitoring element for monitoring the membrane structure and a resistance element for detecting an electrical resistance of at least one region of the membrane (92 ).

12. Pressure sensor measuring element according to one of the preceding claims for a pressure sensor for pressure detection in a combustion chamber (76) of a

Internal combustion engine during operation, wherein the membrane is a separation membrane (92), wherein a plunger (108) for transmitting

Deflections of the separation membrane (92) on a force measuring element (88) is provided, wherein the sleeve (94) receives the plunger (108) and a the

Combustion chamber (76) is closed by the separating membrane (92) and at the opposite second end (72) for holding the force-measuring element (88) is formed, wherein the plunger (108), the membrane (92) and the sleeve (94) are integrally formed.

13. Pressure sensor measuring element according to one of the preceding claims, characterized by at least one of several or all of the following

structures:

a) at least one stiffening structure for stiffening against deformation or for influencing resonance frequencies

b) at least one rib (138) or a projection or a ring and / or

c) transverse structures in the form of heat shields (134) and / or

d) at least one channel (120) for passing at least one line (124, 126) or for decoupling an inner structure and an outer

Structure,

e) at least one cavity (104) between an inner and an outer structure, and / or

f) at least one sensor element (122) for monitoring the function or the structure of the membrane (92).

14. Pressure sensor measuring element according to one of the preceding claims, made of steel, stainless steel or of a NiCrNbMo alloy.

15. Pressure sensor, in particular combination sensor for detecting both pressure (84) and a temperature (78), comprising

Pressure sensor measuring element (66) according to one of the preceding claims.