EP2712726B1 - Tablet press - Google Patents

Description

The invention relates to a tablet press. With the tablet press, for example, tablets can be pressed in the pharmaceutical sector, in the food sector and / or in the field of food supplements. The tablet press has an electric machine for driving a press rotor. The electric machine is provided as a motor for a drive system. For driving the press rotor electrical drives with a high overall performance and low heat losses are advantageous. It is also advantageous to form a tablet press in a compact design.

EP 1 627 727 A2 describes a rotary tablet press with a rotor having a Matritzenscheibe and guides for upper and lower punch, a rotor shaft driving a drive motor, which itself has a rotor and a stator, ,, wherein the rotor is arranged directly on the rotor shaft.

DE 1.0 2010 031 107 A1 describes a forming press with at least one oriented in the press direction or in the press transverse direction axis, wherein the axis is arranged fixed to the frame in or on a press frame. Next, the press on an eccentric disc, wherein the eccentric disc is in operative connection with a segment motor.

US 2005/0003038 A1 describes a tablet press, wherein the tablet press has a direct drive.

WO 2011/050988 A1 and WO 2011/050987 A1 each discloses a pelleting press, wherein the disclosed pelleting presses are each driven via a die axis by a direct drive.

An object of the invention is to provide an improved tablet press. A solution of the problem results in a tablet press with the features of claim 1. Further improvements are obtained according to the features of one of the dependent claims 2 to 7.

A tablet press has a press rotor and an electric machine for driving the press rotor, the electric machine having a stator and a rotor. The stator of the electric machine has segments. The segments of the stator form part of a direct drive for the tablet press. This press is thus designed such that the drive of the press rotor is effected by a direct drive.

In one embodiment of the tablet press, the direct drive is arranged concentrically to the press rotor. In this case, in a further embodiment of the press rotor permanent magnets, so that the press rotor is at the same time the rotor of the electric machine. In a further embodiment, the electric machine has its own rotor with permanent magnets, wherein the rotor is mechanically fixed and connected directly to the tablet rotor.

In one embodiment of the tablet press, the electric machine is a synchronous machine. The synchronous machine can be well controlled in a wide speed range and shows a good torque curve.

By using a direct drive system with a permanently energized synchronous motor and saving on maintenance-requiring mechanical components a wear-free, accurate and dynamic operation of the tablet press is possible.

An embodiment of the synchronous motor in segmental design allows its use for a variety of tablet press rotor sizes and easy installation, since rotor and stator of the electric machine can be handled separately. A further simplification of the assembly can be achieved if both rotor and stator are each divided into circular segment-shaped modules, which together form the rotor or stator of the electric machine.

According to one embodiment of the tablet press, the rotor and the stator of the synchronous motor are arranged in separate planes and at least partially surround the tablet press rotor. This allows a particularly space-saving arrangement. In addition, the synchronous motor can be designed, for example, as a segment motor, and the permanent magnet arrangement can comprise segment-wise arranged on a support plate permanent magnets which cooperate with segmentally arranged windings of a winding body of the stator. This allows a cost-effective production of the drive system by resorting to a variety of similar components.

A direct drive of the tablet rotor has the described advantage over a drive solution based on a servomotor with belt and / or worm gear drives in that fewer mechanical components are used which generate a high level of maintenance. In one embodiment of the tablet press The press rotor (the tablet press rotor) can also be driven by means of a direct drive, which is flanged to a main shaft. This can be a torque motor, for example.

In a tablet press, in which the press rotor is driven directly without the power transmission by means of a main shaft, there is an even more direct and thus even stiffer drive of the press rotor than in a direct drive of a main shaft, the main shaft transmits the force to the press rotor.

In one embodiment of the tablet press, this therefore has a direct drive, in which the direct drive is close to the head of the tablet press, so close to the tablet rotor. The direct drive is advantageously located in or on the tablet rotor. By using segments on the stator, torque grading can also be very flexible, so that it is easy to adapt to already constructed tablet presses. Thus, high development costs or retrofit costs for geometrically and performance-specifically custom-made special motors in the field of direct drive technology in tablet presses can be omitted or reduced and possibly the technical, financial and time required to replace damaged gearboxes or drive systems can be avoided.

A tablet press can be formed in such a way that it has a press rotor and an electric machine, in particular a synchronous machine, wherein in particular the stator is segmented, the press rotor being mechanically rigidly coupled directly to the electric machine without a shaft.

This has advantages over a concept for driving a tablet press, which is based on a combination of motor, belt and gear, or a combination of torque motor and shaft as a mechanical connecting element (for example via keyway). In particular, the drive train with belt and gearbox has high losses (low overall efficiency) and high maintenance costs.

In the case of a shaftless drive, the achievable control quality of the electrical machine can also be improved. This makes it possible to run exact speed profiles. So it is also possible for. B. hard to press powder not by sudden application of a constant force, but to press by an increasing force profile.

A method for pressing a tablet is accordingly designed such that an electric machine is regulated as a function of a force profile. The force profile depends on the material from which the tablet is to be pressed. In an advantageous embodiment, the force profile during the pressing process on a positive derivative on time. The force profile also has a multiplicity of maxima within one revolution of the press rotor. The number of maxima correlates to the number of tablets which can be pressed in one revolution of the press rotor.

In one embodiment of the tablet press, this has a segment motor in radial flow design on the press rotor. The advantage of using a motor in radial flow design is the possibility of direct attachment of the active parts with appropriate mechanical design. The active parts are located in the stator. As a result, an additional construction for the motor carrier structure can be avoided. This motor allows a variable and precise adaptation to the torque required for the respective size / performance level of the tablet press. Furthermore, the engine can be easily adapted to the available space.

• eine direkte Integration des Antriebsstrangs in den Pressenrotor;
• eine hohe mechanische Steifigkeit;
• eine hohe erreichbare Regelgüte;
• eine kleinere erreichbare Maschinenkonstruktion;
• eine Kosteneinsparung durch einen geringeren Materialeinsatz in der Maschinenkonstruktion;
• eine verbesserte Wartungsfreiheit;
• einen Aufbau der elektrischen Maschine aus Linearmotoraktivteilen mit Haupt- und Präzisionskühlung;
• ein Abfahren von komplexen Drehzahlprofilen um Kraftprofile am Material (aus dem Material wird die Tablette gepresst) zu erzeugen;
• ein Erreichen einer höheren Sicherheitskategorie für die Tablettenpresse, da keine "unsichere" Mechanik wie ein Riemen im Antriebsstrang enthalten ist; und/oder
• ein direktes Geberkonzept durch direkten Anbau eines Gebers an den Läufer oder den Pressenrotor, wobei der Geber mit einem Regler zur Regelung der elektrischen Maschine zur Istwertübermittlung verbunden ist, wobei der Geber insbesondere ein Drehzahlgeber und/oder ein Lagegeber ist.

Depending on the structural design, a variety of advantages can be achieved with the shaftless direct drive. This is for example the following:

• a direct integration of the drive train in the press rotor;
• a high mechanical rigidity;
• a high achievable control quality;
• a smaller achievable machine design;
• a cost saving through a lower material usage in the machine design;
• improved maintenance freedom;
• a construction of the electric machine of linear motor active parts with main and precision cooling;
• a departure from complex speed profiles to create force profiles on the material (from the material the tablet is pressed);
• achieving a higher safety category for the tablet press as there is no "unsafe" mechanism such as a belt in the drive train; and or
• a direct encoder concept by direct attachment of an encoder to the rotor or the press rotor, wherein the encoder is connected to a controller for controlling the electric machine for actual value, wherein the encoder is in particular a speed sensor and / or a position sensor.

In one embodiment of the tablet press, the stator of the electric machine is a primary part of the electrical machine, wherein the segments of the stator each have electrical connections. This makes it particularly easy to interconnect a different number of segments with different tablet presses in a tablet press together or to energize separately or in groups on a power converter.

In one embodiment of the tablet press, the electric machine has a disk-shaped air gap. The disc shape allows for easy stator and runners below to place the press rotor, wherein the overall height of the tablet press compared to a driven via a main shaft rotor significantly reduced and the radial space of the press is not adversely affected.

In one embodiment of the tablet press, the electric machine has a cylindrical air gap. As a result, the stator and the rotor of the electric machine can be arranged circumferentially around the press rotor. Thus, the height of the tablet press can be reduced. The fact that the electric machine is arranged on an outer circumference of the press rotor, a high torque can be achieved by the distance to the axis of rotation of the press rotor and electric machine. The direct coupling of electrical machine and press rotor eliminates the need for a shaft.

In one embodiment of the tablet press, the press rotor and the rotor have a common bearing. This also reduces costs and / or space. It is of course also possible that the press rotor and rotor are each supported by their own bearings.

In one embodiment of the tablet press, the segments of the stator of the electric machine are arranged in a circle such that the formed circle and / or the formed circle segment has fewer segments than would be possible with a maximum number of segments in the circular arrangement. Consequently, less than a maximum number of segments can be arranged in a circumferential direction of the arrangement of segments of the stator, depending on the required power of the electric machine. If fewer segments are arranged in a circle, these are advantageously uniform over the circumference, in particular distributed symmetrically.

In one embodiment of the tablet press, the tablet press on pressing cylinder, wherein the pressing cylinder are arranged circular, wherein the radius formed thereby is smaller than the distance of the segments of the stator of the electric machine from the axis of rotation of the electric machine.

In one embodiment of the tablet press, the axis of rotation of the electric machine coincides with the axis of the press rotor.

In one embodiment of the tablet press, the rotor of the electric machine has segments. The segments carry permanent magnet. Due to the segmentation of the rotor, a simple adaptation of the electric machine to different radii can take place, which depends on the respective circumference of the rotor of different tablet presses.

• eine flexible Anzahl an Primär- und/oder Sekundärteilen bei gleichem konstruktivem Aufbau des Radialmotors; Infolge unterschiedlicher Summen der generierten Schubkräfte zwischen den Primär- und Sekundärteilen können sich verschiedene Drehmomente am Rotor ergeben; und/oder
• eine Platzierung mehrere elektrischer Maschinen axial untereinander.

With the help of a plurality of segments of the stator and a corresponding corresponding rotor, a simple and robust drive system can be created. By a segmented structure of the electric machine, in particular from linear motor components, that is, from a plurality of smaller motors, the flexibility of the system increases. Such a segment motor has, for example, primary active parts in the stator and secondary magnetic modules in the rotor, which together with the constructive overall design form a permanently excited synchronous motor. This engine design allows a variable and precise adaptation to the torque required for the respective size / performance level of the tablet press. A variable design of the output torque / the installation space can be realized in different ways. Examples are listed below:

• a flexible number of primary and / or secondary parts with the same structural design of the radial motor; As a result of different sums of the generated thrust forces between the primary and secondary parts, different torques can arise on the rotor; and or
• a placement of several electrical machines axially with each other.

A tablet press can be built up flexibly, in particular, if it has an electrical machine which is segmented. The electric machine of the press may have a plurality of segments, wherein in particular a plurality of segments each have separate electrical connections. The segments are designed such that they have a radial magnetic flux during operation of the electrical machine. The segments are electrically interconnected. It is also possible that segments of different electrical machines are electrically connected to the same tablet press. These can then be controlled, for example, with the same converters and regulated with the same controllers.

FIG 1

eine erste Tablettenpresse;

FIG 2

eine zweite Tablettenpresse;

FIG 3

eine dritte Tablettenpresse;

FIG 4

eine vierte Tablettenpresse;

FIG 5

einen perspektivische Ansicht einer ersten elektrischen Maschine;

FIG 6

einen Schnitt durch die erste elektrische Maschine;

FIG 7

eine fünfte Tablettenpresse mit einer zweiten elektrischen Maschine;

FIG 8

eine dritte elektrische Maschine;

FIG 9

einen Läufer der dritten elektrischen Maschine;

FIG 10

einen Stator der dritten elektrischen Maschine;

FIG 11

einen Läufer und einen Stator einer vierten elektrischen Maschine;

FIG 12

eine fünfte elektrische Maschine.

In the following the invention will be described and explained in more detail with reference to the embodiments illustrated in the figures. Show it:

FIG. 1

a first tablet press;

FIG. 2

a second tablet press;

FIG. 3

a third tablet press;

FIG. 4

a fourth tablet press;

FIG. 5

a perspective view of a first electric machine;

FIG. 6

a section through the first electric machine;

FIG. 7

a fifth tablet press with a second electric machine;

FIG. 8

a third electric machine;

FIG. 9

a rotor of the third electric machine;

FIG. 10

a stator of the third electric machine;

FIG. 11

a rotor and a stator of a fourth electric machine;

FIG. 12

a fifth electric machine.

The representation according to FIG. 1 shows a first tablet press 1. The tablet press 1 has a base 12 and a press rotor 2 with pressing cylinders 3, wherein via a hopper pressed material 11 is zugebbar to press out of the pressed material tablets. The press rotor 2 is rotatable about an axis 4. The tablet rotor 2 (pressing head) is mounted via a shaft 10 connected thereto, the shaft 10 being supported by bearings 13 and 14. The shaft 10 is driven by a belt drive 5 from an electric machine 6. The electric machine 6 forms the main drive of the tablet press 1, so that the shaft 10 can also be referred to as the main shaft. The electric machine 6 is in a control cabinet. 9

In the following, further aspects of the invention will be described by way of example, the same reference numerals being used for the same components.

The representation according to FIG. 2 shows a second tablet press 1, wherein in this the drive of the press rotor 2 is not driven by a belt drive that is driven by an electric machine, but by an electric machine 7, which is directly coupled to the main shaft 10. This avoids the maintenance of a belt. The reliability of the Antiebssystems is increased.

The representation according to FIG. 3 shows a third tablet press 1, wherein the press rotor 2 is mechanically coupled to an electric machine 8. The electric machine 8 is in the FIG. 3 symbolically represented by means of a press rotor 2 comprehensive rectangle. The electric machine 8 does not drive as in FIG. 2 the main shaft 10, but directly and directly the press rotor 2, wherein the main shaft is mounted on two bearings 13 and 14. A rotor of the electric machine 8 is connected directly to the press rotor 2. This makes the drive system even stiffer and can be controlled more dynamically. It is also advantageous that the height can be reduced.

The representation according to FIG. 4 shows in section a fourth tablet press 1, in which the main shaft 10 in comparison to the embodiment according to FIG. 3 is shortened and the storage is done only by a bearing 14. About the bearing 14 is both the press rotor 2 as well as in FIG. 3 not explicitly illustrated rotor of the electric machine 8 stored. The rotor and stator of the electric machine form an intermediate air gap, which has a kind of cylindrical shape. The axes of rotation of rotor and press rotor 2 match.

The representation according to FIG. 5 shows a perspective view of a first electric machine 8, which in a tablet press 1 after 3 or 4 could be used. The schematic representation after FIG. 5 shows a radial segment motor in perspective view. The segment motor has a rotor 15. The rotor 15 has a support structure 16, on which permanent magnets are positioned. The permanent magnets are in FIG. 5 not shown, since they are located on the support structure and the stator 18 are facing. The stator 18 of the segment motor 8 has stator segments 19. Each segment 19 of the stator is constructed such that it represents a primary part with a three-phase winding and has an electrical connection 20 for operation and for energizing. In the event that an electric machine with less power is sufficient, but the mechanical dimensions should remain the same, so for example every second stator segment 19 omitted and not be installed in the electric machine. If the number of segments is even, even the position of the remaining segments may remain unchanged.

The representation according to FIG. 6 shows a section through the electric machine 8 after FIG. 5 , Shown is the stator 18 with a Statorträge 21. The stator 18 has primary elements (segments) 19. The segments 19 have, as already in FIG. 5 each illustrated an electrical connection 20. The segments 19 are separated from each other on the stator 21 attached. Between the stator 18 and the rotor 15 there is an air gap 22. The air gap 22 is of cylindrical shape. At the air gap 22 close to the permanent magnets 17, which are mounted on a magnetic carrier 26 of the rotor 26. The magnetic carrier 26 is mechanically fixed to the press rotor, wherein in FIG. 6 the press rotor is not shown. Also not shown is the variant, to install permanent magnets 17 directly on the press rotor. For an electric machine 8 after FIG. 5 or 6, the press rotor 2 can be partially integrated into the machine, wherein the rotor forms a kind of pan for receiving the press rotor 2. Not applicable in a variation of the bottom of such a trough remains for the runner a kind of ring structure in which the press rotor can be accommodated. In an advantageous embodiment of the magnetic carrier 26 is executed laminated.

The representation according to FIG. 7 shows a fifth tablet press with a second electric machine 8. This second electric machine has a support plate 27 for the press rotor 2. The press rotor 2 is located above the electric machine 8. This electric machine 8 also has permanent magnets 17 on the rotor 15, as well as segments 18 as part of the stator 18. The stator 18 is fixedly connected to a housing 28 of the tablet press 1. The rotor 15 of the electric machine and the press rotor 2 is supported by a bearing 23.

The representation according to FIG. 8 shows a third electric machine 8, which has a stator 18 and a rotor 15, wherein the rotor 15 is mounted via a bearing 24. The rotor 15 has permanent magnets 17 and a carrier plate 27. The permanent magnets 17 are positioned on the carrier plate 27 and are arranged opposite to the stator 18. Between the stator 18 and rotor 15 is the air gap 22. The air gap 22 has a planar ring structure. The areal extent of the air gap 22 is orthogonal to the axis of rotation 4. On the carrier plate 27 is the press rotor to position. By forming the air gap in a plane, a compact horizontal and vertical construction of the tablet press can be achieved. Again, the illustration is schematic and does not reflect the size ratio between rotor of the electric machine and press rotor again.

The representation according to FIG. 9 Figure 15 shows a rotor 15 similar to the third electric machine FIG. 8 , here also the rotor 15 is segmented. The rotor 15 has permanent magnets 17, wherein a plurality of permanent magnets in a rotor segment 25 is grouped. For clarity, only two segments 25 are shown. Due to the segmentation of the rotor, this can be made easier because groups of permanent magnets are already present and then these groups together form the rotor with. The rotor 15 has the segment-wise permanent magnet arrangement on a support ring 29, wherein the support ring 29 is supported by the bearing 24.

The representation according to FIG. 10 shows a stator 18 similar to that of the third electric machine FIG. 8 , wherein the to the rotor segments 25 after FIG. 9 corresponding segments of the stator 19 are shown. The stator 18 after FIG. 10 acts with the runner 15 after FIG. 9 together.

The representation according to FIG. 11 shows a rotor segment 25, wherein permanent magnets are cast or covered by a thin cover layer of metal, so that these permanent magnets no longer visible to the outside. In addition to the rotor segment 25, a corresponding stator segment 19 with an electrical connection 20 is shown. For cooling the segment 19 of the stator, cooling connections 30 are provided for introducing or discharging a cooling liquid.

The representation according to FIG. 12 schematically shows a fifth variation of an electric machine 8 in a double comb arrangement. In the double comb arrangement, at least two permanent magnets 31, 32 are radially in a same position (horizontal), but differ in their vertical position. The same applies to the segments 33 and 34 of the stator 18. The segment 33 of the stator 18 cooperates with permanent magnets having the position of the permanent magnet 31. The segment 34 of the stator 18 cooperates with permanent magnets having the position of the permanent magnet 32. By the double comb arrangement two parallel air gaps 35 and 36 are formed. The air gaps 35 and 36 are each in a plane, wherein the planes of the two air gaps are aligned parallel to each other. With the help of the double comb arrangement can be increased in a simple manner in a compact design, the power per volume occupied by the electric machine.

Claims (7)

1. Tablet press (1), which comprises a press rotor (2) and an electric machine (8) for driving the press rotor (2), the electric machine (8) comprising a stator (18) and a rotor (15), the stator (18) comprising segments (19) and the rotor (15) comprising segments (25), characterized in that the electric machine (3) has a disc-shaped air gap (35, 36) and in that permanent magnets of the segments (25) of the rotor (15) are cast or covered by a thin covering layer of metal, so that these permanent magnets no longer protrude visibly toward the outside.
2. Tablet press (1) according to Claim 1, the stator (18) being a primary part of the electric machine and segments (19) comprising electrical terminals (20).
3. Tablet press (1) according to either of Claims 1 and 2, the electric machine (3) being coupled directly to the press rotor (2).
4. Tablet press (1) according to one of Claims 1 to 3, the press rotor (2) and the rotor (15) having a common bearing (14).
5. Tablet press (1) according to one of Claims 1 to 4, the segments (19) being arranged circularly in such a way that the circle formed and/or the circular segment formed comprises fewer segments (19) than a maximum number of segments in the circular arrangement.
6. Tablet press (1) according to one of Claims 1 to 5, the tablet press (1) comprising pressing cylinders (3), the pressing cylinders (3) being arranged circularly, the radius formed as a result being smaller than the distance of the segments (19) from the axis of rotation (4) of the electric machine (3).
7. Tablet press (1) according to one of Claims 1 to 6, the axis of rotation (4) of the electric machine (3) coinciding with the axis of the press rotor (2).

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