DE102020106362A1 - Hydraulic moving device, positioning device with and method for operating a hydraulic moving device - Google Patents

Abstract

The invention relates to a hydraulic moving device (2), a positioning device (40) with a hydraulic moving device (2) and a method for operating the hydraulic moving device (2). The hydraulic traversing device (2) comprises a diaphragm lifting ram (4) which encloses a working volume, and a hydraulic adjusting element including a chamber with a variable chamber volume, the working volume and the chamber volume being fluidically connected and a total volume of working volume and chamber volume being completed and is constant at all times, and wherein the hydraulic adjusting element comprises a bellows protruding into the chamber, which can be changed lengthwise to change the chamber volume via a drive element.

Description

The invention relates to a hydraulic moving device, a method for operating a hydraulic moving device and a positioning device with a hydraulic moving device.

Moving and positioning devices for positioning and aligning objects or samples are used in various areas of technology.

A positioning device for precisely positioning and aligning an energy source is, for example, off DE 199 63 194 A1 known. This positioning device is constructed in the form of a tripod, with each individual leg extending between a base and a movable / positionable table. Each of the three legs includes a linear drive with which the length of the respective leg can be changed. In this way it is possible to position the table, which carries the energy source, freely in the room

Positioning devices are also used at measuring stations where samples are examined using synchrotron radiation. In this case, high demands are made on the positioning devices. For example, the sample must be freely positionable in space at such a measuring station in order to align it optimally in relation to the spatially fixed beam. The positioning device must also work very precisely and reproducibly.

The object of the invention is to specify an improved hydraulic displacement device, an improved method for operating a hydraulic displacement device and an improved positioning device with a hydraulic displacement device.

The object is achieved by a hydraulic traversing device comprising a diaphragm lifting ram, which includes a working volume, and a hydraulic adjusting element, comprising a chamber with a variable chamber volume, the working volume and the chamber volume being fluidically connected and a total volume of working volume and chamber volume being completed and is constant at all times, and wherein the hydraulic adjusting element comprises a bellows protruding into the chamber, which can be changed lengthwise to change the chamber volume via a drive element.

In the context of the present description, “bellows” is understood to mean both a bellows in the usual technical sense, but also a corrugated bellows and / or a diaphragm bellows.

The hydraulic traversing device advantageously exclusively comprises solid body joints in order to move the diaphragm lifting ram. It is thus possible for the entire fluidic system of the hydraulic displacement device to represent a closed system, that is to say is hermetically sealed off from an outside space of the hydraulic displacement device. This qualifies the hydraulic traversing device, for example, for use in a vacuum or high vacuum. In addition, the hydraulic traversing device is extremely low-maintenance. An incompressible hydraulic fluid, for example a hydraulic oil or an alcohol, is used as the hydraulic fluid. If, according to one embodiment, alcohol is used as the hydraulic fluid, the hydraulic displacement device can also be operated at low temperatures. In addition, in the extremely unlikely event of a leak, alcohol poses a much lower risk of contamination to vacuum components than oil. The hydraulic traversing device is also due to the fact that it does not include any mechanical joints or the like, not only extremely low-maintenance, but also play-free. The structure is structurally simple and compact.

The diaphragm lifting ram of the hydraulic traversing device is designed in particular as a diaphragm bellows with one or more folds. For example, the diaphragm lifting ram is a diaphragm bellows with only a single fold.

The working volume and the chamber volume are fluidically connected to one another. For this purpose, the working volume and chamber volume are either directly connected to one another or a connecting line extends between the working volume of the diaphragm lifting ram and the variable chamber volume of the hydraulic adjusting element. When considering the total volume, which is constant at each operating time of the hydraulic displacement device, according to such an embodiment, not only the chamber volume and the working volume but also the volume of the connecting line are considered. In this case, the total volume is the total of the working volume, the chamber volume and the volume of the connecting line, the total volume always being constant.

To actuate the diaphragm lifting ram, the volume is shifted from the chamber volume to the working volume of the diaphragm lifting ram or vice versa. If the diaphragm lifting ram is to be extended, the bellows protruding into the chamber is expanded over the drive element, so that it extends extends further into the chamber and reduces the chamber volume. This difference in the chamber volume increases to the working volume of the diaphragm lifting ram, which causes it to extend. Should the diaphragm lifting ram be retracted, the drive element is retracted and the bellows protrudes less far into the chamber volume. The working volume of the diaphragm lifting ram is now reduced by this difference in the chamber volume and the diaphragm lifting ram moves back.

A transmission ratio between the travel of the drive element of the hydraulic adjusting element and the stroke of the diaphragm lifting ram can be set by changing a ratio between the cross-sectional area of the diaphragm lifting ram and the cross-sectional area of the bellows, more precisely the end face of the bellows. For example, a bellows with a small cross-sectional area (face) will displace a smaller volume in the chamber volume than a bellows with a larger cross-sectional area with the same change in length, i.e. the same travel path of the drive element. With the same change in length, the drive element, in cooperation with a bellows with a smaller cross-section, causes a smaller stroke on the diaphragm lifting ram than in cooperation with a bellows with a larger cross-section. Depending on the requirements, the maximum stroke of the diaphragm lifting ram, the fineness in which it can be moved and the maximum force of the diaphragm lifting ram (assuming constant force of the drive element) can be adjusted by selecting the appropriate cross-sectional ratios. A bellows with a small cross-section allows a very fine and precise adjustment of the stroke of the diaphragm lifting ram with great force at the same time, while a bellows with a larger cross-section enables the greater stroke at the expense of precision and force. The transmission ratio defines a power gain. If the transmission ratio is selected to be large, i.e. if a bellows with a small cross section is used to change the chamber volume, a large increase in force can be achieved, so that only moderate forces have to be applied in order to generate large forces on the diaphragm lifting ram.

According to a further embodiment, the hydraulic traversing device comprises a distance sensor which detects the stroke of the diaphragm lifting ram. On the basis of a measured value from the distance sensor, a further included and suitable control device can control and / or regulate an automated control of the stroke of the diaphragm lifting ram. For this purpose, the suitably set up control system evaluates the measured value of the distance sensor and controls or regulates the drive element in such a way that the desired stroke is set on the membrane lifting ram.

According to an advantageous embodiment, the hydraulic displacement device is developed in that a working fluid present in the working volume and the chamber volume is under excess pressure.

In order to achieve this, for example, the fluidic system is filled with excess pressure. In particular, bubble-free filling takes place. The preload in the hydraulic system can ensure that it works without play and therefore with high precision.

This property of the hydraulic traversing device can be further improved in that, according to a further embodiment, the diaphragm lifting ram is preloaded, in particular a restoring force of the diaphragm lifting ram being greater than a restoring force of the bellows.

Normally the restoring forces of the diaphragm lifting ram and the bellows add up. The construction mentioned ensures that the diaphragm lifting ram always keeps the bellows under pressure. The drive element can be designed in such a way that it only supports the bellows on one side. This simplifies the construction of the hydraulic control element. For example, a drive element can be provided which is implemented via a lengthwise adjustable linear drive, for example a movable mandrel or, in the simplest case, a screw that extends in the interior of the bellows, which supports the bellows on its inner end face. A compressive force always acts between the end face of the bellows and such a linear drive due to the prestress from the diaphragm lifting ram. No mechanical connection is required between such a linear drive and the bellows, the drive being free of play at the same time. This considerably simplifies the construction of the hydraulic traversing device. In addition, the hydraulic traversing device is not only backlash-free, but also extremely rigid and precise.

According to a further advantageous embodiment, the hydraulic displacement device is developed in that the membrane lifting ram and / or the bellows are / is designed as metallic membrane or corrugated bellows.

Metallic membrane bellows and corrugated bellows are suitable for vacuum because they are absolutely tight. A hydraulic traversing device according to this embodiment is therefore particularly suitable for vacuum and high vacuum applications.

The object is also achieved by a method for operating a hydraulic traversing device which comprises a membrane lifting ram which includes a working volume and which comprises a hydraulic adjusting element with a chamber with a variable chamber volume, the working volume and the chamber volume being fluidically connected and hermetically sealed and the hydraulic adjusting element comprises a bellows protruding into the chamber, the chamber volume of the adjusting element being changed by changing a length of the bellows with the aid of a drive element in order to move the diaphragm lifting ram.

The same or similar advantages apply to the method for operating the hydraulic traversing device as were already mentioned with regard to the hydraulic traversing device. To avoid repetition, reference is made to the advantages mentioned above.

The object is also achieved by a positioning device with a positionable holder, which is connected to and supported on a support structure via at least one hydraulic displacement device according to one or more of the aforementioned embodiments, a fine positioning device for positioning an object being arranged on the holder.

Such a positioning device works with high precision, is mechanically extremely rigid and absolutely free of play. It is also constructed in a relatively simple manner and is extremely compact. This optimally qualifies such a positioning device for use at a measuring station for research with synchrotron radiation. The positioning device is also suitable for vacuum.

The positioning device is developed in particular in that the holder is connected to the support structure in the manner of a tripod with three hydraulic displacement devices and is supported against the support structure.

The construction of the positioning device in the manner of a tripod allows the holder to be freely positioned in space. For example, the holder can be positioned at the desired position up to the limits of the structurally possible accuracy of the positioning device, then the fine positioning device is used for fine positioning of the object. The fine positioning device is, for example, a stack of piezo elements that enables the object to move in three spatial directions.

The positioning device is furthermore advantageously developed in that the hydraulic displacement devices combine the mechanical function of a linear drive and a ball joint.

For example, a positioning device is to be moved which comprises three hydraulic moving devices which are arranged in the manner of a tripod. If only one of the three hydraulic traversing devices is now moved, the two remaining hydraulic traversing devices that have not been moved each act in the manner of a ball-and-socket joint. The moved hydraulic moving device acts as a linear drive with a ball joint at each end. In this example, the positioning device provides the mechanical functionality of four ball joints and a linear drive, with solid body joints being used exclusively.

Further features of the invention will become apparent from the description of embodiments according to the invention together with the claims and the accompanying drawings. Embodiments according to the invention can fulfill individual features or a combination of several features.

In the context of the invention, features that are identified with “in particular” or “preferably” are to be understood as optional features.

• 1 eine schematische und vereinfachte Schnittansicht einer hydraulischen Verfahreinrichtung und
• 2 eine schematisch und vereinfachte perspektivische Darstellung einer Positioniereinrichtung, umfassend drei nach der Art eines Dreibeins angeordnete hydraulische Verfahreinrichtungen.

The invention is described below without restricting the general inventive concept on the basis of exemplary embodiments with reference to the drawings, with express reference being made to the drawings with regard to all inventive details not explained in more detail in the text. Show it:

• 1 a schematic and simplified sectional view of a hydraulic displacement device and
• 2 a schematic and simplified perspective illustration of a positioning device, comprising three hydraulic displacement devices arranged in the manner of a tripod.

In the drawings, the same or similar elements and / or parts are provided with the same reference numerals, so that they are not introduced again in each case.

1 shows a hydraulic traversing device in a schematic and simplified sectional view 2 with a membrane lifting ram 4th and a hydraulic adjustment element 6th . The membrane lifting ram 4th and the hydraulic adjustment element 6th are via a connecting line 10 fluidically connected to each other. The membrane lifting ram 4th closes a volume of work 8th a. The hydraulic adjustment element 6th includes a chamber 14th with a variable chamber volume 12th . The volume of work 8th and the chamber volume 12th are in the present embodiment via the line volume 16 fluidically connected to each other. A total volume of work volume 8th , Line volume 16 and chamber volume 12th is constant at all times. The fluidic system is therefore completely closed or, in other words, hermetically sealed.

An incompressible hydraulic fluid, for example a hydraulic oil or alcohol, is present in the total volume. The hydraulic adjustment element 6th includes one in the chamber 14th protruding bellows 18th . With the bellows 18th it can also be a membrane and / or corrugated bellows; a bellows is merely an example 18th Referenced. All explanations apply in the same way to a diaphragm bellows, a corrugated bellows or a combination of the different types of bellows. In an interior 20th of the bellows 18th a drive element extends 22nd with which the bellows 18th to change the chamber volume 12th can be changed lengthways. This is how the chamber volume is 12th changeable.

In the illustrated embodiment, it is the drive element 22nd for example a screw whose external thread matches an internal thread of the end bracket 24 is engaged. Will be the drive element 22nd in the interior 20th of the bellows 18th retracted, so if the screw is turned, for example, the bellows is displaced 18th a differential volume from the chamber 14th and the chamber volume 12th gets smaller. The volume of work increases by this difference in volume 8th of the diaphragm lifting ram 4th to. So it is possible by moving the drive element 22nd in one drive direction A. , for example along the longitudinal direction of the screw, a stroke of the diaphragm lifting ram 4th in stroke direction H to create. If the drive element is reversed 22nd from the interior 20th of the bellows 18th along the drive direction A. Retracted a certain distance, the chamber volume increases 12th by a difference in volume. The volume of work increases by this difference in volume 8th of the diaphragm lifting ram 4th so that it runs along the stroke direction H comes in. In this way it is possible to control the movement of the drive element 22nd in the drive direction A. into a stroke of the diaphragm lifting ram 4th in the stroke direction H to translate.

The hydraulic traversing device 2 exclusively uses flexure joints and does not include any moving mechanical components, apart from the drive element 22nd - depending on the version. This enables the hydraulic traversing device 2 , a table 26th , for example to hold and move a sample table or the like with great mechanical rigidity. In addition, the hydraulic traversing device is 2 backlash-free. This is also ensured by the fact that this occurs in the hydraulic system, that is to say in particular in the working volume 8th and the chamber volume 12th , existing hydraulic working fluid is under excess pressure. The membrane lifting ram is used for this 4th biased. A restoring force of the diaphragm lifting ram 4th is greater than a restoring force of the bellows 18th . This structural feature makes the bellows 18th always kept under pressure. Between one face 28 of the drive element 22nd and an internal head side 30th of the bellows 18th is always that of the membrane lifting ram 4th generated overpressure. The adjustment of the bellows takes place through this bias 18th through the drive element 22nd Play-free instead of without complex constructive measures having to be taken.

The membrane lifting ram 4th and / or the bellows 18th are designed, for example, as a metallic diaphragm bellows. In the illustrated embodiment, the membrane lifting ram 4th be a metallic diaphragm with only one fold.

All components of the membrane lifting ram 4th , so for example both the connection between the actual membrane and the bracket of the table 26th as well as the connection of the membrane to the base of the membrane lifting ram shown below the membrane 4th , which in the main body 34 is let in, are preferably designed as welded connections. The basic body 34 is opposite the base of the membrane lifting ram 4th via schematically indicated seals 32 sealed. These can be O-ring seals, Viton seals or copper seals, depending on the area of application of the hydraulic positioning device 2 . The end bracket is the same 24 about seals 32 which can be made in the same way as the previously mentioned seals 32 , opposite the main body 34 sealed. The adjustment element 6th is for safe guidance in the area of its free end opposite the end bracket 24 about suitable bearings 36 supported.

2 shows a positioning device 40 with a table 26th as a positionable holder 42 . The table 26th is via three hydraulic traversing devices 2 , of which in the perspective view of 2 the membrane lifting ram 4th of only two of these hydraulic traversing devices 2 are visible, movable. The membrane lifting ram 4th of the three hydraulic traversing devices 2 are at the table 26th in the manner of a tripod (English tripod) attached and support this against a base body 34 used as a supporting structure 44 acts, from. On the table 26th is a fine positioning device 46 attached with a sample holder 48 and together with this one at the top of the sample holder 48 existing object 50 , for example one with the synchrotron beam 52 sample to be examined can be moved in all three spatial directions X, Y and Z. By moving the membrane lifting ram 4th of the individual hydraulic traversing devices 2 can the object 50 in addition, as indicated by the arrow cross, can optionally be raised or swiveled as a whole. For this purpose, the drive elements 22nd the one in the main body 34 integrated hydraulic traversing devices 2 operated accordingly. Depending on how the individual hydraulic traversing devices 2 , which in the main body 34 as in principle in 1 shown, are integrated, are operated, the membrane lifting rams act 4th the hydraulic traversing devices 2 sometimes as a ball joint, sometimes as a linear drive in conjunction with one or more ball joints. The table 26th can be tilted, whereby its movement is only realized by means of flexure joints.

All of the features mentioned, including those that can be taken from the drawings alone and also individual features that are disclosed in combination with other features, are considered to be essential to the invention alone and in combination. Embodiments according to the invention can be fulfilled by individual features or a combination of several features.

List of reference symbols

2

hydraulic traversing device

4th

Membrane lifting ram

6th

hydraulic adjustment element

8th

Volume of work

10

Connecting line

12th

Chamber volume

14th

chamber

16

Line volume

18th

Bellows

20th

inner space

22nd

Drive element

24

End bracket

26th

table

28

Front side

30th

Head side

32

Seals

34

Base body

36

camp

40

Positioning device

42

holder

44

Support structure

46

Fine positioning device

48

Sample holder

50

object

52

Synchrotron beam

A.

Drive direction

H

Stroke direction

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed 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 19963194 A1 [0003]

Claims (8)

Hydraulic traversing device (2), comprising a membrane lifting ram (4), which encloses a working volume (8), and a hydraulic adjusting element (6), including a chamber (14) with a variable chamber volume (12), the working volume (8) and the chamber volume (12) are fluidically connected and a total volume of the working volume (8) and chamber volume (12) is closed and constant at all times, and the hydraulic adjusting element (6) has a bellows (18) protruding into the chamber (14) comprises, which can be changed in length to change the chamber volume (12) via a drive element (22). Hydraulic traversing device (2) according to Claim 1 , characterized in that a working fluid present in the working volume (8) and the chamber volume (12) is under excess pressure. Hydraulic traversing device (2) according to Claim 1 or 2 , characterized in that the diaphragm lifting ram (4) is preloaded, in particular a restoring force of the diaphragm lifting ram (4) being greater than a restoring force of the bellows (18). Hydraulic traversing device (2) according to one of the Claims 1 until 3 , characterized in that the diaphragm lifting ram (4) and / or the bellows (18) are / is designed as metallic diaphragm or corrugated bellows. A method for operating a hydraulic traversing device (2) which comprises a membrane lifting ram (4) which encloses a working volume (8) and which comprises a hydraulic adjusting element (6) with a chamber (14) with a variable chamber volume (12), wherein the working volume (8) and the chamber volume (12) are fluidically connected and hermetically sealed, and the hydraulic adjusting element (6) comprises a bellows (18) protruding into the chamber (14), whereby for moving the diaphragm lifting ram (4) the chamber volume (12) of the adjusting element (6) is changed by changing a length of the bellows (18) with the aid of a drive element (22). Positioning device (40) with a positionable holder (42), which has at least one hydraulic displacement device (2) according to one of the Claims 1 until 4th is connected to a support structure (44) and supported thereon, a fine positioning device (46) for positioning an object (50) being arranged on the holder (42). Positioning device (40) after Claim 6 , characterized in that the holder (42) is connected to the support structure (44) in the manner of a tripod with three hydraulic displacement devices (2) and is supported with respect to the support structure (44). Positioning device (40) after Claim 7 , characterized in that the hydraulic movement devices (2) combine the mechanical function of a linear drive and a ball joint.

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