DE102021116083A1 - Method for producing a sealing device for an electrical machine and device for carrying it out - Google Patents

Abstract

Method for producing a sealing device (1) for an electrical machine for sealing a stator space from a rotor space, the sealing device (1) being made at least partially from a fiber composite material, comprising the following steps: providing and positioning a flat semi-finished product (2) made from uncured fiber composite material; Cutting the semi-finished product (2) to produce a parallelogram-like blank (12) with two longitudinal sides (22) running parallel to one another and two transverse sides (32) running parallel to one another and at an angle to the longitudinal sides (22); Applying a flexible production aid (3) to a receiving mandrel (4); aligning the blank (12) and the arbor (4) relative to each other such that the longitudinal sides (22) of the blank (12) are positioned perpendicular to an axis of rotation (14) of the arbor (4); Rolling up the blank (12) onto the rotating mandrel (4) equipped with the production aid (3), so that the transverse sides (32) abut without a gap and an uncured cylindrical preform (10) is formed.

Description

The present invention relates to a method for producing a sealing device for an electrical machine. The sealing device is used to seal a stator space from a rotor space and is at least partially made of a fiber composite material.

Such a sealing device is, for example, from DE 10 2017 102 141 A1 famous. There, the uncured fiber composite material is applied to a stator from the inside and then cured in order to create a material connection between the stator and the sealing device. During curing, the sealing device is pressed against the stator. For example, bellows or a metal core is used for this purpose, which expands more when heated than the stator or the fiber composite material.

In contrast, it is the object of the present invention to provide an improved and preferably automatable option for producing such a sealing device. In particular, an economical production with a high quality requirement for the sealing device should be possible.

This object is achieved by a method having the features of claim 1 and by a device having the features of claim 15. Preferred developments of the invention are the subject matter of the dependent claims. Further advantages of the present invention result from the general description and the description of the exemplary embodiment.

The method according to the invention is used to produce a sealing device for an electrical machine. The sealing device is provided for sealing a stator space from a rotor space. The sealing device is made at least partially from at least one fiber composite material. The method comprises the following steps in this order or in another order suitable for production: providing and positioning a flat semi-finished product (so-called prepreg) made of uncured fiber composite material; Cutting the semi-finished product to produce an in particular parallelogram-like blank with two longitudinal sides running parallel to one another and two transverse sides running parallel to one another and at an angle to the longitudinal sides; Application of a flexible production aid to a receiving mandrel (in particular by pushing and/or rolling up); aligning the blank and the arbor relative to each other so that the longitudinal sides of the blank are positioned perpendicular to an axis of rotation of the arbor; Rolling up the blank onto the rotating mandrel equipped with the production aid, so that the transverse sides abut without a gap (especially touching) and an uncured cylindrical preform is formed; in particular providing the preform for positioning and curing in the stator; in particular before or after removing the preform from the receiving mandrel in the axial direction of the receiving mandrel.

The method according to the invention offers many advantages. A significant advantage is that a very precise preform adapted to the stator can be produced in automated process steps. This offers considerable qualitative and also economic advantages compared to a procedure in which uncured pieces of the fiber composite material are individually laminated to the stator from the inside. Overall, the invention enables a particularly reliable and at the same time reproducible production. The cutting of the semi-finished product according to the invention in combination with the rolling up is also particularly advantageous. This enables the semi-finished product to be formed into a cylindrical preform precisely and without any gaps, which in turn offers a robust and mechanically highly effective seal.

The sealing device produced according to the invention can in particular be referred to as a liner. The semi-finished product can in particular also be referred to as a prepreg. The parison can in particular also be referred to as a preform. In particular, the liner is formed (cured) from the preform.

The semi-finished product is preferably fed automatically from at least one roll. In particular, at least one feed device is provided for this purpose. This is particularly advantageous when the production rate is high. It is also possible for the semi-finished product to be fed in automatically piece by piece. For example, partially assembled sections or mats are fed in for this purpose.

Before being cut to size, the semi-finished product is preferably fed into a positively defined processing position by means of at least one manipulator device and preferably in the direction of a 0° fiber direction, in particular to a unidirectional fiber alignment of the semi-finished product.

In particular, at least one machining table with at least one stop is provided for the machining position determined in a form-fitting manner. In particular, the semi-finished product is automatically placed against the at least one stop and preferably against at least two stops by means of the feed device. In particular, for at least one long side of the semi-finished product at least one stop provided. In particular, at least one stop is provided for at least one transverse side of the semi-finished product. In particular, the stop can be aligned and preferably folded down. In all configurations it is preferred that the stop can be extended at least in the z-direction.

The semi-finished product is preferably fixed on a processing table by means of a vacuum, at least during the cutting to size and/or at least during the rolling up onto the receiving mandrel. In particular, the processing table has a plurality of suction points for this purpose.

The negative pressure is preferably adjusted locally in a targeted manner during the rolling up. In particular, as a result, at least those areas of the semi-finished product or blank that have to or should leave the processing table for rolling up are fixed less strongly or not at all.

In all configurations it is preferred that the semi-finished product is cut at an angle at least on the transverse sides by means of at least one manipulator device with at least one cutting unit. Preferably, the stock is cut at an angle to a 0° fiber direction of a unidirectional fiber orientation of the stock. In particular, the semi-finished product is cut at an angle greater than 0°. In particular, the semi-finished product is cut at an angle smaller than a right angle to the 0° fiber direction. For example, the semi-finished product is cut at an angle of 45° to the 0° fiber orientation. Other angles are also possible, for example between 15° and 75° to the 0° fiber orientation. Both transverse sides of the semi-finished product are preferably cut at the same angle to the 0° grain direction. In particular, the transverse sides are cut at an angle such that they run parallel to one another.

It is also possible that the long sides are cut. In particular, the long sides are then cut parallel to a 0° fiber direction. In particular, the long sides are cut so that they run parallel to one another.

In particular, the blank has the geometry of a parallelogram. It is possible for the long sides and short sides to be of the same length, so that the blank has the geometry of a rhombus. Other geometries are also possible.

The arbor preferably includes a plurality of suction ports. In particular, the production aid is sucked in at the suction openings of the receiving mandrel by means of a vacuum. In particular, the negative pressure can be regulated in order to adjust the friction between the production aid and the arbor. In particular, the production aid is made from a material that is pressure-resistant under the pressure conditions to be expected.

The production aid is preferably subjected to an overpressure by means of the suction openings, so that the production aid can be removed from the receiving mandrel in the axial direction together with the preform (without undesired changes in the shape of the preform). The parison can be separated from the receiving mandrel inside or outside the stator. In particular, the production aid is removed from the preform. It is also possible for the production aid to remain on the preform.

A tubular film is preferably used as a production aid. It is also possible and preferred for a shrink tube to be used as the production aid. In all of the configurations, it is preferred that the production aid serves as a carrier material for the preform that has not yet hardened. In particular, the production aid is used to be able to remove the preform from the receiving mandrel. It is possible that the preform will be pressed radially outwards against the stator when positioned in the stator. For this purpose, it can be provided that pressure is exerted on the production tool. The preform can harden at least partially lying against the stator and in particular pressed against the stator.

The production aid is preferably applied by sliding the production aid onto the receiving mandrel. In particular, the production aid is pushed axially onto the (stationary or non-rotatable at this time) receiving mandrel. For example, the production aid is designed as a shrink tube and/or as a (closed) film tube. It is also possible for the production aid to be applied by (automatically) rotating the receiving mandrel.

It is possible and advantageous for the semi-finished product to be equipped with at least one protective film on both sides. In particular, at least one upper protective film is removed before being rolled up onto the receiving mandrel and/or at least one lower protective film is removed after being rolled up onto the receiving mandrel using at least one manipulator device with a suction cup unit and/or a gripping unit. The semi-finished product can also only have a protective film on one side. It is also possible that the semi-finished product has no protective film.

In particular, the semi-finished product is cooled at least in sections to reduce the adhesion of the protective film locally. For example, a means with a lower temperature compared to the ambient temperature or compared to the temperature of the protective film is used for this purpose. In particular, this is done using the manipulator device, which is equipped with a suitable tool unit.

In an advantageous development of the method, the sealing device is made from a two-layer or multi-layer fiber composite material. In particular, the preform comprises at least two coaxially arranged semi-finished products. In particular, the semi-finished products each provide a layer of the preform or the sealing device. In particular, the semi-finished products are positioned and cut in such a way that a blank is available for each semi-finished product, as described above. The blanks are preferably rolled up one after the other onto the receiving mandrel, so that an at least two-layer uncured cylindrical preform is produced. It is also possible that three or more blanks are rolled up, so that a three-layer or multi-layer preform is created. The preform can also be made in one layer.

The semi-finished products for the at least two-layer preform each have, in particular, a unidirectional fiber orientation. In particular, the semi-finished products are cut at an angle to the 0° fiber direction at least on their transverse sides by means of at least one manipulator device. In particular, the transverse sides of the at least one semi-finished product are cut at a different angle to the 0° fiber direction than the transverse sides of the at least one other semi-finished product. The angles particularly preferably differ with regard to their sign. For example, one semi-finished product is cut at an angle of +45° and the other semi-finished product at an angle of -45° on the short sides. In particular, the transverse sides belonging to a semi-finished product are cut at the same angle. In this way, parallel or even overlapping joints can be avoided. The coaxial outer blank is in particular rolled up in such a way that its joint runs at least partially or even completely at a distance from the joint of the coaxial inner blank. In particular, the semi-finished products are aligned parallel to one another in relation to their 0° fiber direction. Angular arrangements of the semi-finished products in relation to their 0° fiber directions are also possible.

In all of the configurations, it is preferred that the receiving mandrel is arranged on a guide device. In particular, the receiving mandrel can be automatically aligned relative to the semi-finished product or blank by the guide device. Such a guide device usually offers a much more precise alignment of the arbor than z. B. a manipulator in the manner of an industrial robot. For this purpose, the guide device z. B. have a uniaxial or a two-axis or multi-axis mobility. For example, the receiving mandrel can be moved along one or along two or else three axes of the guide device. However, the receiving mandrel can also be arranged on a manipulator device and, for example, on an industrial robot.

In particular, the receiving mandrel for rolling up the blank is set in a rotary motion in that the receiving mandrel is rolled over the blank (lying on the processing table). This has the advantage that there is no disruptive relative speed between the mandrel and the blank, and a particularly high level of process reliability is therefore achieved. In particular, a drive of the receiving mandrel can be uncoupled or switched off for this purpose. However, it is also possible for the take-up mandrel to be driven to roll it up.

In particular, the diameter of the receiving mandrel is adapted to a diameter of the preform to be produced. In particular, the arbor is cylindrical. In particular, the receiving mandrel is adapted to the contour of the preform and/or to the contour of a radial inner side of the stator.

The device according to the invention is used to carry out the method for producing a sealing device, as has been described above. The object according to the invention can also be achieved particularly advantageously with such a device.

The device is designed in particular as a machining center. In particular, the device includes the means described above for carrying out the method. In particular, the device is suitable and designed to carry out the method steps described above. In particular, the device comprises at least one receiving mandrel. In particular, the device comprises at least one manipulator device and in particular at least one guide device and in particular at least one processing table and in particular at least one feed device. The receiving mandrel is in particular coupled to the guide device. However, it is also possible for the receiving mandrel to be coupled to the manipulator device.

In particular, the manipulator device comprises at least one suction cup unit and/or gripping unit. The manipulator device is example wise formed as an industrial robot or other device that provides an arm with one or two or more axes of movement. In particular, the processing table comprises at least one and preferably at least two adjustable stops.

In particular, the device comprises at least one cutting unit. The cutting unit is preferably coupled to a guide device and particularly preferably to the guide device of the receiving mandrel. The cutting unit is attached in particular where the arbor is also attached. This offers particularly precise guidance of the cutting unit. Although it is also possible to use the cutting unit z. B. to mount on a robotic arm, but this is not recommended for maximum precision results. The cutting unit can be arranged so that it can move or also be stationary on the guide device. The cutting unit can be arranged on the arbor.

An uncured fiber composite mat is preferably provided as the semi-finished product. In particular, the semi-finished product consists of at least one fiber composite material. In particular, the semi-finished product comprises at least one matrix material and at least one type of reinforcement fibers which are embedded in the matrix material. A continuous fiber-reinforced plastic is preferably provided. In all configurations it is provided that the semi-finished product has a unidirectional fiber orientation. The semi-finished product can also be referred to as a so-called UD scrim (unidirectional scrim). A two- or multi-directional fiber orientation or a fabric, mesh and/or a similar suitable semi-finished product is also possible.

In particular, the blank is rolled onto the receiving mandrel in such a way that the fibers of the blank run at least partially parallel over the circumference of the receiving mandrel and, in particular, meet in a ring-like manner at the ends. In particular, the fiber ends of the individual fibers meet at least approximately and preferably touching one another. However, it is also possible for the fibers to meet in an offset manner. In particular, the fibers run concentrically around a longitudinal axis of the receiving mandrel or concentrically around a longitudinal axis of the preform. However, the fibers can also run transversely or helically around the longitudinal axis of the receiving mandrel or the preform.

Further advantages of the present invention result from the exemplary embodiments which are explained below with reference to the enclosed figures.

• 1 eine stark schematisierte Darstellung einer erfindungsgemäßen Vorrichtung während der Herstellung einer Abdichteinrichtung nach dem erfindungsgemäßen Verfahren;
• 2 die Vorrichtung der 1 bei einem anderen Schritt des Verfahrens;
• 3 die Vorrichtung der 1 bei einem weiteren Schritt des Verfahrens; und
• 4 die Vorrichtung der 1 bei noch einem weiteren Schritt des Verfahrens.

In the figures show:

• 1 a highly schematic representation of a device according to the invention during the production of a sealing device according to the method according to the invention;
• 2 the device of 1 at another step of the method;
• 3 the device of 1 at a further step of the method; and
• 4 the device of 1 at yet another step in the process.

the 1 shows a device 7 for carrying out a method according to the invention for producing a sealing device 1 for an electrical machine, which has not yet been completed here. The device 7 is designed here, for example, as a machining center and includes at least one manipulator device 5 with a plurality of interchangeable machining tools. The manipulator device 5 is, for example, equipped as an industrial robot with one or more arms.

In the following, the operation of the device 7 when carrying out the production method according to the invention with reference to FIG 1 until 4 presented in more detail.

A semi-finished product 2 or prepreg, for example made of glass fiber reinforced plastic, is applied to a processing table 6 via a feed device 8 . It can be made up directly from a prepreg roll or made up of prepregs that are introduced piece by piece. The semi-finished product 2 here has a unidirectional fiber orientation (UD scrim). The feed device 8 enables the semi-finished products 2 to be fed in at the later storage angle.

The semi-finished product 2 is then positioned/pulled out by means of the manipulator device 5 with a suction cup unit 25 and/or a gripping unit 35. The semi-finished product 2 is aligned on two or more stops 26 (extendable in the z-direction, foldable). The angular position and the feed of the semi-finished product 2 can be adjusted using the feed device 8 and by selecting the positioning angle and the arrangement of the stops 26 . The 0° fiber direction here corresponds to the direction of feed.

The semi-finished product 2 is then securely fixed in position via suction points 16 integrated in the processing table 6 . By means of a mechanically designed cutting unit 15, for example, the semi-finished product 2 is then cut to size.

In the example shown here, the production of a 2-layer sealing device 1 is provided. Therefore, two semi-finished products 2 are arranged on the processing table 6 here. That in the 1 The semi-finished product 2 shown on the right is already available as a finished blank 12 . The other semi-finished product 2 is still being processed with the cutting unit 15.

The semi-finished products 2 are cut here in such a way that blanks 12 each have two longitudinal sides 22 running parallel to one another and two transverse sides 32 running parallel to one another and at an angle to the longitudinal sides 22 . For example, a cutting line with an angle of +45° to the 0° fiber orientation is provided for the blank 12, which forms the first layer. For the second blank 12, which forms the second layer, a cutting line of -45° to the 0° fiber orientation is provided, for example. Thus, with the device 7 presented here, it is possible to cut both semi-finished products 2 to size, each with a defined angular orientation.

An upper protective film 42 of the blank 12 for the first layer is then automatically pulled off (see 2 ). A refrigerant, for example CO2, is used here to locally reduce the adhesive effect or adhesion. The refrigerant is z. B. from the arm of the manipulator device 5 made. The manipulator device 5 then removes the protective film 42 by means of a suction cup unit 25 and/or a gripping unit 35.

In order to produce a cylindrical sealing device 1, the manipulator device 5 is equipped here with a receiving mandrel 4 or winding mandrel, which can be rotated about an axis of rotation 14, for winding up the semi-finished products 2 (see FIG 3 ). For precise alignment relative to the blank 12, the receiving mandrel 4 can be moved here by means of a guide device that is not shown in detail. In particular, the cutting unit 15 is also attached to the guide device.

Before the semi-finished products 2 are rolled up, a production aid 3 in the form of a (plastic) film tube 23 is applied to the receiving mandrel 4 (e.g. by pushing it on axially or by rolling it up). Alternatively or additionally, a shrink tube 33 can also be provided.

The mandrel 4 is made here, for example, from steel, aluminum or a fiber-reinforced plastic. The arbor 4 here has a plurality of bores, for example more than 25, which are distributed over its circumference and length. The bores provide suction openings 24 which serve to suck in the production tool 3 . By creating a negative pressure area between the receiving mandrel 4 and the film tube 23, the friction can be increased and the film tube 23 can be reliably fixed together with the rolled-up semi-finished product 2.

Like in the 3 shown, after the film tube 23 has been applied, the blank 12 for the first layer is rolled up. For this purpose, the holding mandrel 4 is aligned in such a way that the longitudinal sides 22 of the blank 12 are positioned at right angles to an axis of rotation 14 of the holding mandrel 4 . The blank 12 is then rolled up by rotating the receiving mandrel 4 . Then the receiving mandrel 4 is rolled over the blank 12 and thereby set in a rotary motion so that the blank 12 can be rolled up precisely. A drive of the arbor 4 is decoupled.

By rolling up in this way, the blank 12 is here converted into a cylindrical tube without a recognizable joint. The fibers and the matrix material are arranged parallel in the joint area. The result is a smooth and gap-free arrangement for the rolled-up blank 12. During the rolling-up, the suction pressure is regulated zone-specifically or zone-wise at the suction points 16 of the processing table 6, so that optimal rolling-up can take place.

The lower protective film 42 is then pulled off the rolled-up semi-finished product 2, as shown in FIG 4 is shown. The lower protective film 42 is removed here, for example, in the manner previously described for the upper protective film 42 .

The receiving mandrel 4 is then aligned relative to the blank 12 for the second layer. The blank 12 is then rolled up in the manner described above for the first layer. If additional layers are provided for the sealing device 1, these are rolled up in the same way.

An uncured cylindrical preform 10 is now located on the receiving mandrel 4. A liner, which provides the sealing device 1, can now be produced from the preform 10 by targeted curing, for example in the stator.

After all the intended semi-finished products 2 have been rolled up onto the receiving mandrel 4 , pressure is applied through the suction openings 24 , so that areas of overpressure arise between the receiving mandrel 4 and the film tube 23 . This leads to a reduction in the contact area and to less friction between the film tube 23 and receiving mandrel 4. A particularly smooth movement in the axial direction can thus take place, for example in order to remove the preform 10 from the receiving mandrel 4. The manipulator device 5 can have a tool in order to remove the preform 10 from the receiving mandrel 4 at excess pressure, e.g. B. the gripping unit 35 and/or the suction cup unit 25.

The removal can preferably take place before the introduction of the preform 10 into the stator. However, it is also possible for the holding mandrel 4 to be inserted into the stator for positioning the preform 10 and for the holding mandrel 4 to be separated from the preform 10 only after it has been positioned in the stator.

The invention offers an industrial production of a preform 10 with one or more fiber layers without disturbing fiber separation over the entire circumference. In addition, a precise rolling up for gap-free contact of the respectively limiting fibers of the blanks 12 is made possible, so that fiber layers without gaps between the fibers are possible. Such freedom from gaps is particularly relevant for a robust and mechanically highly effective seal using a liner. In addition, the invention makes it possible to roll it up within a narrow range of tolerances in terms of diameter and length. A further advantage is that the blanks 12 can be rolled up directly onto the production aid 3 and in particular the film tube 23 or also onto a shrink tube 33 . The invention also offers full automation, including removing the protective film 42.

Reference List

1

sealing device

2

Workpiece

3

production aids

4

mandrel

5

manipulator device

6

processing table

7

contraption

8th

feeding device

10

preform

12

cutting

14

axis of rotation

15

cutting unit

16

suction point

22

long side

23

film tube

24

suction openings

25

suction cup unit

26

attack

32

transverse side

33

shrink tubing

35

gripping unit

42

protective film

QUOTES INCLUDED IN DESCRIPTION

This list of the 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 102017102141 A1 [0002]

Claims (15)

Method for producing a sealing device (1) for an electrical machine for sealing a stator space from a rotor space, wherein the sealing device (1) is made at least partially from a fiber composite material, comprising the following steps: Providing and positioning a flat semi-finished product (2) made of uncured fiber composite material; Cutting the semi-finished product (2) to produce a parallelogram-like blank (12) with two longitudinal sides (22) running parallel to one another and two transverse sides (32) parallel to one another and at an angle to the longitudinal sides (22); Applying a flexible production aid (3) to a receiving mandrel (4); aligning the blank (12) and the receiving mandrel (4) relative to one another, so that the longitudinal sides (22) of the blank (12) are positioned perpendicular to an axis of rotation (14) of the arbor (4); Rolling up the blank (12) onto the rotating mandrel (4) equipped with the production aid (3), so that the transverse sides (32) abut without a gap and an uncured cylindrical preform (10) is formed. Method according to the preceding claim, in which the semi-finished product (2) is automatically fed in from at least one roll or in pieces. Method according to one of the preceding claims, wherein the semi-finished product (2) is fed into a positively determined processing position in the direction of a 0° fiber direction of a unidirectional fiber alignment of the semi-finished product before cutting by means of at least one manipulator device (5). Method according to one of the preceding claims, in which the semi-finished product (2) is fixed on a processing table (6) by means of a vacuum, at least during the cutting and/or rolling up onto the receiving mandrel (4). Method according to the preceding claim, wherein the negative pressure is adjusted locally in a targeted manner during the rolling up in order to fix at least those areas of the semi-finished product (2) less strongly or not at all which have to leave the processing table (6) for rolling up. Method according to one of the preceding claims, wherein the semi-finished product (2) is cut at least on the transverse sides (32) by means of at least one manipulator device (5) with a cutting unit (15) at an angle to a 0° fiber direction of a unidirectional fiber orientation of the semi-finished product. Method according to one of the preceding claims, in which the holding mandrel (4) has a large number of suction openings and in which the production aid (3) is sucked in at the suction openings (24) of the holding mandrel (4) by means of negative pressure. Method according to the preceding claim, wherein the production aid (3) is subjected to an overpressure at the suction openings (24), so that the preform (10) together with the production aid (3) can be removed from the receiving mandrel (4) in the axial direction. Method according to one of the preceding claims, in which a film tube (13) or a shrink tube (23) is used as the production aid (3). Method according to one of the preceding claims, in which the semi-finished product (2) is equipped on both sides with at least one protective film (42) and in which at least one upper protective film (42) before it is rolled up onto the receiving mandrel (4) and at least one lower protective film (42) after being rolled up onto the receiving mandrel (4), it is pulled off by means of at least one manipulator device (5) with a suction cup unit (25) and/or a gripping unit (35). Method according to the preceding claim, wherein the semi-finished product (2) is cooled at least in sections for local adhesion reduction of the protective film (42). Method according to one of the preceding claims, wherein the preform (10) comprises at least two coaxially arranged semi-finished products (2) and the semi-finished products (2) are each positioned and cut to size so that a blank (12) is available for each semi-finished product (2) and the blanks (12) being rolled up one after the other onto the receiving mandrel (4), so that an at least two-layer, uncured cylindrical preform (10) is produced. Method according to the preceding claim, wherein the semi-finished products (12) each have a unidirectional fiber orientation and wherein the semi-finished products (12) are cut at an angle to the 0° fiber direction at least on their transverse sides (32) by means of at least one manipulator device (5) and the transverse sides (32) of the at least one semi-finished product (2) in one be cut at a different angle to the 0° fiber direction than the transverse sides (32) of the at least one other semi-finished product (2). Method according to one of the preceding claims, in which the receiving mandrel (4) is arranged on a manipulator device (5) and is rolled over the blank (12) in order to be rolled up. Device (7) for carrying out the method according to one of the preceding claims.

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