DE102020215528A1 - Method for filling an oil reservoir of a pressure sensor with a pressure transmission medium and device for carrying out the method - Google Patents

Abstract

A method for filling an oil reservoir (100) of a pressure sensor with a pressure transmission medium (110) is presented, in which a device (200) is used which has a pressure chamber (201) for receiving the oil reservoir (100) and one in the pressure chamber (100) arranged filling device (202) and suction device (203), wherein the filling device (202) has a first channel (220) for supplying the pressure transmission medium (110), wherein the suction device (203) has a second channel (230) for supplying closure elements ( 210) and a third channel (240) for sucking off air and/or excess pressure transmission medium (110). Furthermore, the invention relates to a device for carrying out the method.

Description

State of the art

Pressure sensors are known from the prior art that use what is known as an oil template in order to transfer the pressure to a pressure sensor element. Such pressure sensors are, for example, from DE 10 2018 222 779 A1 and the DE 10 2014 211 928 A1 known. With such sensors, the pressure to be measured of a liquid or gaseous medium present at a connection piece of the pressure sensor is not transmitted directly to a pressure sensor element, but only indirectly via the oil reservoir to protect the pressure sensor element from an aggressive medium or aggressive substances contained therein. The oil reservoir comprises a cavity filled with a pressure transmission medium (usually a hydraulic oil) and having at least one wall section which can be deformed by the action of the pressure applied to the connecting piece. The wall section can also be formed by a membrane attached to a base body of the oil reservoir. The deformation of the membrane or the wall section leads to a pressure transmission to the pressure transmission medium and from there to a pressure sensor element. In the case of the known pressure sensors, the oil reservoir has a filling opening, which is closed with a closing element after it has been filled with the pressure-transmitting medium.

When filling the oil reservoir with the pressure transmission medium, air pockets in the oil reservoir must be avoided. However, this can cause some difficulties due to the general conditions during production.

Disclosure of Invention

• - Bereitstellen einer Vorrichtung mit einer Druckkammer zur Aufnahme der Ölvorlage sowie mit einer in der Druckkammer angeordneten Befüllungseinrichtung und Absaugeinrichtung, wobei die Befüllungseinrichtung einen ersten Kanal zur Zuführung des Druckübertragungsmediums aufweist, wobei die Absaugeinrichtung einen zweiten Kanal zur Zuführung von Verschlusselementen sowie einen dritten Kanal zur Absaugung von Luft und/oder überschüssigem Druckübertragungsmedium aufweist,
• - Bereitstellen eines Grundkörpers der Ölvorlage, wobei der Grundkörper eine im Inneren des Grundkörpers ausgebildete Kavität sowie wenigstens eine mit der Kavität verbundene erste Öffnung und zweite Öffnung aufweist,
• - Zuführen des Grundkörpers in die Druckkammer der Vorrichtung,
• - Abpumpen von Luft aus der Druckkammer,
• - Annähern der Befüllungseinrichtung an den Grundkörper derart, dass der erste Kanal über die erste Öffnung mit der Kavität verbunden ist und Annähern der Absaugeinrichtung an den Grundköper derart, dass der zweite Kanal und dritte Kanal über die zweite Öffnung mit der Kavität verbunden sind,
• - Zuführen des Druckübertragungsmediums über den ersten Kanal der Befüllungseinrichtung und die erste Öffnung in die Kavität und Abführung von in der Kavität enthaltenen Gasen über die zweite Öffnung und den dritten Kanal der Absaugeinrichtung solange bis die gesamte Kavität bis zu der zweiten Öffnung mit dem Druckübertragungsmedium aufgefüllt ist,
• - Einpressen eines in dem zweiten Kanal der Absaugeinrichtung enthaltenen ersten Verschlusselementes in die zweite Öffnung zur Abdichtung derselben,
• - Entfernen der Befüllungseinrichtung und der Absaugeinrichtung von dem Grundkörper,
• - erneutes Annähern der Absaugeinrichtung an den Grundköper derart, dass der zweite Kanal und dritte Kanal über die erste Öffnung mit der Kavität verbunden ist und
• - Einpressen eines in dem zweiten Kanal der Absaugeinrichtung enthaltenen zweiten Verschlusselementes in die erste Öffnung zur Abdichtung derselben und
• - Entfernen der Absaugeinrichtung von dem Grundkörper.

The invention proposes a method for filling an oil reservoir of a pressure sensor with a pressure transmission medium, which comprises the following steps:

• - Providing a device with a pressure chamber for receiving the oil reservoir and with a filling device and suction device arranged in the pressure chamber, the filling device having a first channel for supplying the pressure transmission medium, the suction device having a second channel for supplying closure elements and a third channel for suction of air and/or excess pressure transmission medium,
• - providing a base body for the oil reservoir, the base body having a cavity formed inside the base body and at least one first opening and second opening connected to the cavity,
• - feeding the base body into the pressure chamber of the device,
• - evacuation of air from the pressure chamber,
• - Approach the filling device to the base body in such a way that the first channel is connected to the cavity via the first opening and the suction device is approached to the base body in such a way that the second channel and third channel are connected to the cavity via the second opening,
• - Supplying the pressure transmission medium via the first channel of the filling device and the first opening into the cavity and removal of gases contained in the cavity via the second opening and the third channel of the suction device until the entire cavity up to the second opening is filled with the pressure transmission medium ,
• - pressing a first closure element contained in the second channel of the suction device into the second opening to seal it,
• - Removal of the filling device and the suction device from the base body,
• - Approaching the suction device again to the base body in such a way that the second channel and third channel are connected to the cavity via the first opening and
• - pressing a second closure element contained in the second channel of the suction device into the first opening to seal the same and
• - Removal of the suction device from the base body.

Furthermore, the invention relates to a device for carrying out the method presented above, which has a pressure chamber for receiving a base body of the oil reservoir and a filling device and suction device arranged in the pressure chamber, the filling device having a first channel for supplying the pressure transmission medium and the suction device having a second channel for Has supply of closure elements and a third channel for suction of air and / or excess pressure transmission medium.

In the context of the present application, an oil reservoir is understood to be a component which comprises a base body filled with a liquid pressure transmission medium, which has at least one deflectable wall section or a membrane and which is intended to be used by the To transfer pressure transmission medium recorded pressure to a pressure sensor element. The pressure transmission medium can be hydraulic oil.

A base body of the oil reservoir is understood to be a body with a cavity that is suitable for receiving hydraulic fluid. The base body is preferably made of plastic, but could also be made of metal. The base body can have a thin-walled wall section or a membrane fastened to the base body by welding, for example. The base body can have a pressure sensor element which can be inserted into the base body. However, the base body can also have a pressure sensor channel which is intended for connection to a pressure sensor element which can be arranged on an outside of the base body.

A filling device is understood to mean a device which is suitable for removing the pressure transmission medium from a container and feeding it to a first opening in a base body of the oil reservoir. The filling device can be designed, for example, as a cannula or pipette or similar.

A suction device is understood to mean a device that can remove gas displaced from the oil reservoir or excess pressure transmission medium that emerges from the second opening of the base body, without this contaminating the pressure chamber. The suction device is additionally provided to provide closure elements and to press them into the openings of the oil reservoir in order to close these openings.

A pressure chamber is understood to mean a chamber in which a pressure below atmospheric pressure can be generated. A vacuum can preferably be generated in the pressure chamber.

Approaching the filling device to the base body or approaching the suction device to the base body means that an end of the filling device intended for filling and the base body are moved towards one another, or that an end of the suction device intended for filling and the main body are moved towards one another. This can be done by lowering the filling device or the suction device onto a stationary base body or by raising the base body in the direction of the filling device or the suction device.

Advantages of the Invention

The method according to the invention makes it possible for the oil reservoir to be reliably filled with a pressure transmission medium and for air pockets to be avoided.

On the one hand, this can be achieved in that the base body of the oil reservoir is filled in a pressure chamber that was previously evacuated. The evacuation ensures that the air from the outside space does not penetrate into the cavity of the oil reservoir before it can be closed. Furthermore, the main body of the oil reservoir is provided with two openings, with the pressure transmission medium being filled in via the first opening. The second opening advantageously serves as an outgassing opening. The pressure transmission medium penetrating into the cavity of the oil reservoir gradually fills up the cavity. Any residual amount of gas that may be present in the cavity is thereby displaced in the direction of the second opening. The suction device absorbs this gas and discharges it. As soon as the pressure transmission medium has completely filled the cavity, any pressure transmission medium emerging from the second opening is also removed via the suction device and the filling is terminated. The suction device has an inner channel via which a closure element is guided to the second opening. The closure element can be pressed into the second opening by means of a press die. The pressure transmission medium that is displaced in the process is discharged via the suction device. Advantageously, the suction device can be moved to the first opening and there press a second closure element into the first opening in the same way.

Advantageous refinements and developments of the invention are made possible by the features contained in the dependent claims.

Particularly advantageously, the filling device has a first sealing element at its end intended to approach the base body, and the suction device has a second sealing element at its end intended to approach the base body. When the filling device approaches the base body, the first sealing element will seal the first opening from the pressure chamber. When the suction device approaches the base body, the second sealing element can seal the second opening from the pressure chamber and preferably seals the first opening from the pressure chamber when the suction device approaches the base body again. By sealing the first and second openings against the pressure chamber is advantageously achieved that no pressure transmission medium gets into the pressure chamber during filling.

During the pressing of the first closure element into the second opening and/or during the pressing of the second closure element into the first opening, excess pressure transmission medium can advantageously be sucked off by means of the suction device without contaminating the pressure chamber.

Before the suction device is removed from the base body, the third channel of the suction device can advantageously be closed in order to prevent the residual gas and/or pressure transmission medium contained in the third channel that has been suctioned off from escaping from the open suction device.

Also advantageous is a device for carrying out the method described, in which the device has a pressure chamber for receiving a base body of the oil reservoir and a filling device and suction device arranged in the pressure chamber, the filling device having a first channel for supplying the pressure transmission medium, the suction device having a second channel for supplying closure elements and a third channel for sucking off air and/or excess pressure transmission medium and the filling device has a first sealing element at its end intended for approaching the main body of the oil reservoir and the suction device at its end intended for nearing the main body of the oil reservoir End has a second sealing element. The first and second sealing element can be produced, for example, as a vulcanized rubber seal.

The filling device and the suction device can be designed as movable parts that can be lowered and raised independently of one another in the pressure chamber. However, it is also possible for the filling device and the suction device to be part of a common processing head, which processing head can be lowered and raised in the pressure chamber.

An embodiment in which the suction device has an inner cannula in which the second channel runs is particularly advantageous. An outer cannula surrounding the inner cannula can have the third channel.

The outer cannula can be designed, for example, as a hollow cylinder and can be rotated about the inner cannula. By rotating the outer cannula relative to the inner cannula, a passage between the second channel and the third channel can advantageously be opened and closed, so that a backflow or outgassing of suctioned material from the third channel can be advantageously avoided when the suction device is lifted.

character list

• 1 eine Ansicht einer Vorrichtung zur Durchführung eines Verfahren zur Befüllung einer Ölvorlage eines Drucksensors
• 2 ein vergrößertes Detail der Absaugeinrichtung aus 1,
• 3a bis 3f zeigen schematisch verschiedene Verfahrensschritte bei der Durchführung des Verfahrens.

Possible embodiments of the invention are explained below with reference to the attached drawing. Show in the drawing:

• 1 a view of a device for carrying out a method for filling an oil reservoir of a pressure sensor
• 2 an enlarged detail of the suction device 1 ,
• 3a until 3f show schematically different process steps in the implementation of the method.

Embodiments of the invention

1 1 schematically shows a device 200 for filling an oil reservoir 100 of a pressure sensor. The pressure sensor itself is not shown.

The device 200 has a pressure chamber 201 (represented by the box in 1 ). The pressure chamber 201 can be evacuated by pumping out the air initially contained therein.

The device 200 also has a filling device 202 and a suction device 203 . The filling device 202 can be designed as a pipette or cannula or similar. The filling device 202 comprises a tube in which a first channel 220 for supplying a pressure transmission medium 110 is formed. The inside diameter of the channel 220 can be one millimeter, for example, and the wall thickness of the tube wall can be 0.3 to 0.5 mm, for example. The filling device 202 has a first sealing element 204 in the form of a ring seal vulcanized onto the end face of the pipe at its end provided for approaching the base body 101 of the oil reservoir 100 . The annular sealing element 204 has an internal recess in order not to impede the passage of the pressure transmission medium. The pressure transmission medium 110 provided for the filling can be taken from a container and filled into the oil reservoir 100 by means of the filling device 202 .

The suction device 203 has a second channel 230 for the supply of closure elements ten 210 on. The closure elements 210 are preferably designed as metal balls with a diameter of 0.8 mm, for example, and can be fed to the second channel 230 from the outside. However, the closure elements can also have a different shape. Furthermore, the suction device 203 has a third channel for sucking off air and/or excess pressure transmission medium 110 .

As shown in the enlarged view of 2 can be seen better, the suction device 203 can have, for example, an inner cannula 231 in which the second channel 230 runs. The closure elements 210 can be fed into the second channel 230 and can be pressed with a press die 250 in 2 be pressed down. Furthermore, the suction device 203 can have, for example, an outer cannula 241 surrounding the inner cannula 231, in which the third channel 240 is formed. The outer cannula 241 can, for example, be designed in the shape of a hollow cylinder and its inner wall can be pushed over the outer wall of the inner cannula 231 . The third channel 240 forms, for example, a circumferential annular channel that is closed off at its end by a surface, but can also be designed differently. The outer cannula 241 is preferably designed to be rotatable around the inner cannula 231 . As in 2 can also be seen that the outer cannula 241 at the end of the third channel 240 can have a lateral undercut 242 and the inner cannula 231 at the end of the second channel 230 can have a corresponding lateral undercut 232 . By rotating the outer cannula 241 relative to the inner cannula 231 , the undercut 242 is congruent with the undercut 232 and the third channel 240 is connected to the second channel 230 . With a further rotation of the outer cannula 241 relative to the inner cannula 231, the inner wall of the outer cannula 241 slides over the undercut 232 of the inner cannula and the passage between the third channel 241 and the second channel 231 can be closed.

As continues in 1 is shown, a base body 101 of the oil reservoir 100 comprises a cavity 103 formed inside the base body 101 and at least one first opening 104 and second opening 105 connected to the cavity 103. The cavity 103 is from outside the base body via the first opening and second opening accessible. The base body 101 has 1 has a thin-walled wall section 102 on its underside, which serves as a membrane. A pressure sensor element 106 can be arranged inside the cavity 103 . However, pressure sensor element 106 can also be fastened to the outside of base body 101 and connected to cavity 103 via a pressure channel (not shown). The base body 101 is preferably made of plastic.

In the following, the method for filling the oil reservoir 100 is now based on the 3a until 3f described.

First, as in 3a is shown, the base body 101 is supplied to the oil reservoir 100 of the pressure chamber 201 and the air is pumped out of the pressure chamber 201 .

Before or after the pressure chamber 201 is pumped down, as in 3b is shown, the filling device 202 and the suction device 203 can be lowered onto the base body 101 in any order. The first opening 104 and the second opening 105 of the base body 101 are provided on the same side of the base body 101, so that the filling device 202 and the suction device 203 can approach from the same side. Alternatively or additionally, the base body 101 is raised in the direction of the filling device 202 and the suction device 203 if these are anchored in a stationary manner in the pressure chamber, for example.

When the filling device, suction device and base body approach each other relatively, the filling device 202 is brought closer to the base body 101 in such a way that the first channel 220 is connected to the cavity 103 via the first opening 104 . Accordingly, the suction device 203 is approached in such a way that the second channel 230 and third channel 240 are connected to the cavity 103 via the second opening 105 . The second channel 230 is preferably centered in relation to the second opening 105 .

When the filling device 202 approaches the base body 101 , the first sealing element 204 seals off the first opening 104 from the pressure chamber 201 . When the suction device 203 approaches the base body 101 , the second sealing element 205 seals the second opening 105 from the pressure chamber 201 .

As in 3c can also be seen, a pressure transmission medium 110 is now filled into the cavity 103 by means of the filling device 202 . In the process, the remaining gas possibly contained in the cavity 103 is displaced in the direction of the second opening 105 . The pressure transmission medium 110 rises in the cavity 103 until it reaches the second opening 105 . The gas emerging from the second opening 105 is sucked off via the third channel 240 . In addition, it is also possible to additionally suck off the gas via the second channel 230 if no closure element 210 has yet been supplied there. before A benefit of the suction device is that the escaping gas can be sucked off directly at the second opening 105 .

As continues in 3d is shown, a first closure element 211 contained in the second channel 230 of the suction device 240 is then pressed into the second opening 105 to seal it by means of a press die 250 guided in the channel 230 . The first closure element 211 can be fed automatically to the second channel 230 at the end of the filling process or can already be contained therein at the beginning. When it is pressed into the second opening 105 , pressure transmission medium that may have been displaced outwards from the second opening is sucked off directly via the third channel 240 .

Subsequently, by rotating the outer cannula 241 relative to the inner cannula 231 in 2 the passage between the third channel 240 and the second channel 230 can be closed and the suction device 203 can be lifted off the base body. Closing the third channel 240 prevents material that has already been sucked off from escaping into the pressure chamber when it is lifted. In addition, the filling device 202 is also lifted off the base body 101 .

In the penultimate step of 3e the suction device 203 approaches the base body 101 again in such a way that the second sealing element 205 seals the first opening 104 this time and the second channel 230 and third channel 240 are connected to the cavity 103 via the first opening 104 . The second channel 230 is preferably centered with respect to the first opening 104 . A second closure element 212 is then pressed into the first opening 215 analogously to the procedure for pressing in the first closure element 211 .

Finally, as in 3f shown, the suction device 203 is lifted off the base body 101 and the filling process of the oil reservoir 100 is completed. The finished oil reservoir 100 can now be removed from the pressure chamber 201 .

It goes without saying that the method presented here as an example for filling an oil reservoir 100 of a pressure sensor can also be modified within the limits of the present invention. For example, it is possible to carry out the pressing-in process of the second closure element with a further suction device constructed in the same way as the suction device 203 . In addition, it is also possible, for example, to arrange the filling device 202 and the suction device 203 on a common processing head, which moves the two devices synchronously. This head is then simply moved laterally over the base body 101 for the pressing-in process of the second closure element 212 . Other changes are also conceivable. That's how it is 2 Although the structure of the suction device 203 shown is particularly advantageous, the suction device can also be designed differently. It is particularly advantageous for the method presented here that the suction device can carry out the two functions suction and pressing in of closure elements at the same time.

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102018222779 A1 [0001]
• DE 102014211928 A1 [0001]

Claims (10)

Method for filling an oil reservoir (100) of a pressure sensor with a pressure transmission medium (110), comprising the following steps: - Providing a device (200) with a pressure chamber (201) for receiving the oil reservoir (100) and with a pressure chamber (100) arranged with a filling device (202) and suction device (203), wherein the filling device (202) has a first channel ( 220) for supplying the pressure transmission medium (110), the suction device (203) having a second channel (230) for supplying closure elements (210) and a third channel (240) for sucking off air and/or excess pressure transmission medium (110). , - Providing a base body (101) of the oil reservoir (100), the base body (101) having a cavity (103) formed inside the base body (101) and at least one first opening (104) and second opening connected to the cavity (103). (105) has, - feeding the base body (101) into the pressure chamber (201) of the device, - pumping air out of the pressure chamber (201), - Approaching the filling device (202) to the base body (101) in such a way that the first channel (220) is connected to the cavity (103) via the first opening (104), and approaching the suction device (203) to the base body (101 ) such that the second channel (230) and third channel (240) are connected to the cavity (103) via the second opening (105), - Supplying the pressure transmission medium (103) via the first channel (220) of the filling device (202) and the first opening (104) into the cavity (103) and discharging gases contained in the cavity (103) via the second opening (105) and the third channel (240) of the suction device (203) until the entire cavity (103) up to the second opening (105) is filled with the pressure transmission medium (110), - pressing a first closure element (211) contained in the second channel (230) of the suction device (240) into the second opening (105) to seal the latter, - Removing the filling device (202) and the suction device (203) from the base body (101), - Approaching the suction device (203) again to the base body (101) in such a way that the second channel (230) and third channel (240) are connected to the cavity (103) via the first opening (104) and - pressing a second closure element (212) contained in the second channel (230) of the suction device (203) into the first opening (104) in order to seal it and - Removing the suction device (203) from the base body (101). procedure after claim 1 characterized in that the filling device (202) has a first sealing element (204) at its end intended to approach the base body (101) and the suction device (203) has a second sealing element (205 ) and that - when the filling device (202) approaches the base body (101), the first sealing element (204) seals the first opening (104) from the pressure chamber (201) and that - when the suction device (203) approaches the base body (101) the second sealing element (205) seals the second opening (105) from the pressure chamber (201) and preferably - when the suction device (203) approaches the base body (101) again, the second sealing element (205) seals the first opening (105 ) against the pressure chamber (201) seals. procedure after claim 1 or 2 , characterized in that while the first closure element (211) is being pressed into the second opening (105) and/or while the second closure element (212) is being pressed into the first opening (104), the suction device (203) removes excess pressure-transmitting medium (110) sucks off Method according to one of the preceding claims, characterized in that the third channel (240) is closed before the suction device (203) is removed from the base body (101). Device (200) for carrying out the method according to one of Claims 1 until 4 , characterized in that the device (200) has a pressure chamber (201) for receiving a base body (101) of the oil reservoir (100) and a filling device (202) and suction device (203) arranged in the pressure chamber (100), the filling device (202) has a first channel (220) for supplying the pressure transmission medium (110), the suction device (203) having a second channel (230) for supplying closure elements (210) and a third channel (240) for sucking off air and/or or excess pressure transmission medium (110). Device (200) according to claim 5 , characterized in that the filling device (202) at its approach to the base body (101) of the oil reservoir (100) end provided a first sealing element (204) and the Absaugeinrich Device (203) has a second sealing element (205) at its end intended to approach the base body (101) of the oil reservoir (100). Device (200) according to one of Claims 5 or 6 , characterized in that the filling device (202) and the suction device (203) can be lowered and raised independently of one another in the pressure chamber (201). Device (200) according to one of Claims 5 or 6 , characterized in that the filling device (202) and the suction device (203) are part of a common processing head, which processing head in the pressure chamber (201) can be lowered and raised. Device (200) according to one of Claims 5 until 8th , characterized in that the suction device (203) has an inner cannula (231) in which the second channel (230) runs and an outer cannula (241) surrounding the inner cannula (231) with the third channel (240). Device (200) according to claim 9 , characterized in that the outer cannula (241) is hollow-cylindrical and rotatable about the inner cannula (231), wherein rotating the outer cannula (241) relative to the inner cannula (231) creates a passage between the second channel (230) and the third Channel (240) can be opened and closed.

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