Gearbox assembly for a twin-screw extruder, treatment installation for material treatment comprising a gearbox assembly of this type, and method for the startup of a treatment installation comprising a gearbox assembly of this type

Abstract

A gearbox assembly for a twin-screw extruder comprises a speed change gearbox for adjusting a screw shaft speed of two screw shafts of the twin-screw extruder, a distribution gearbox allowing the screw shafts to be coupled thereto, and a speed reduction gearbox. The speed change gearbox and the speed reduction gearbox are configured such as to be separable from each other, wherein the speed change gearbox is arranged at a driving end while the speed reduction gearbox couples the speed change gearbox to the distribution gearbox. Due to the fact that the speed change gearbox is configured as an individual gearbox unit arranged at the driving end, an adjustment of the screw shaft speed is easily possible by replacing the speed change gearbox. As a result, a high flexibility and productivity are obtained in the operation of the twin-screw extruder.

Claims

1. A gearbox assembly for a twin-screw extruder, comprising: a speed change gearbox for adjusting a screw shaft speed of shafts of a twin-screw extruder; a speed reduction gearbox; and a distribution gearbox with two distribution gearbox output shafts allowing the screw shafts of the twin-screw extruder to be coupled thereto, wherein the speed change gearbox is arranged at a driving end, wherein the speed reduction gearbox couples the speed change gearbox to the distribution gearbox, wherein the speed reduction gearbox has precisely one speed reduction gearbox input shaft, the precisely one speed reduction gearbox input shaft having a first speed reduction gearbox gear and a speed reduction output shaft having a second speed reduction gearbox gear, the first speed reduction gearbox gear and the second speed reduction gearbox gear being in meshing engagement, wherein a speed change gearbox output shaft of the speed change gearbox is detachably connected to the precisely one speed reduction gearbox input shaft so that the speed change gearbox and the speed reduction gearbox are configured such as to be separable from each other, wherein a speed change gearbox housing of the speed change gearbox and a speed reduction gearbox housing of the speed reduction gearbox are configured such as to be separate from each other.

2. The gearbox assembly according to claim 1, wherein the speed change gearbox has a speed change gearbox input shaft at the driving end allowing a drive motor to be detachably coupled thereto.

3. The gearbox assembly according to claim 1, wherein the speed change gearbox output shaft has a gear disposed at the output end thereof, and wherein the speed change gearbox output shaft is mounted, by means of radial bearings, on both sides of the gear.

4. The gearbox assembly according to claim 3, wherein the speed change gearbox output shaft is mounted to a speed change gearbox housing.

5. The gearbox assembly according to claim 1, wherein the precisely one speed reduction gearbox input shaft has the first speed reduction gearbox gear disposed at the input end thereof, and wherein the precisely one speed reduction gearbox input shaft is mounted, by means of radial bearings, on both sides of the first speed reduction gearbox gear.

6. The gearbox assembly according to claim 5, wherein the precisely one speed reduction gearbox input shaft is mounted to the speed reduction gearbox housing.

7. The gearbox assembly according to claim 1, wherein a speed change gearbox input shaft and the speed change gearbox output shaft are mounted to the speed change gearbox housing, wherein the speed change gearbox housing has a connection portion for connection to the speed reduction gearbox housing, the connection portion being configured in such a way that the speed change gearbox input shaft is positionable in a plurality of angular positions relative to the speed change gearbox output shaft.

8. The gearbox assembly according to claim 1, wherein at least one lubricant line having a predetermined separation point runs between the speed change gearbox and the speed reduction gearbox.

9. The gearbox assembly according to claim 8, wherein the predetermined separation point of the at least one lubricant line is arranged outside the speed change gearbox housing and the speed reduction gearbox housing.

10. The gearbox assembly according to claim 1, wherein the speed change gearbox has a coding element for reading out a gear ratio.

11. The gearbox assembly according to claim 1, wherein the speed reduction gearbox output shaft is detachably connected to a distribution gearbox input shaft of the distribution gearbox.

12. The gearbox assembly according to claim 1, wherein the speed reduction gearbox has the speed reduction gearbox output shaft and the second speed reduction gearbox gear is disposed at the output end thereof, and the speed reduction gearbox output shaft is mounted, by means of radial bearings, on both sides of the second speed reduction gearbox gear.

13. The gearbox assembly according to claim 12, wherein the speed reduction gearbox output shaft is mounted to the speed reduction gearbox housing.

14. The gearbox assembly according to claim 1, wherein the distribution gearbox has a distribution gearbox input shaft and a gear disposed at the input end thereof, and wherein the distribution gearbox input shaft is mounted, by means of radial bearings on both sides of the gear.

15. The gearbox assembly according to claim 14, wherein the distribution gearbox input shaft is mounted to a distribution gearbox housing.

16. The gearbox assembly according to claim 1, wherein the speed reduction gearbox housing and a distribution gearbox housing of the distribution gearbox are configured such as to be separate from each other.

17. A gearbox assembly according to claim 1, wherein the speed reduction gearbox has a gear ration of i.sub.R defined by an input speed n.sub.R of the precisely one speed reduction gearbox input shaft and by an output speed of n.sub.V of the speed reduction gearbox output shaft, wherein the gear ratio i.sub.R is constant such that: i.sub.R=n.sub.R/n.sub.V>1.

18. A treatment installation for material treatment, comprising: a twin-screw extruder comprising two screw shafts; a gearbox assembly comprising a speed change gearbox for adjusting a screw shaft speed of the two screw shafts of the twin-screw extruder, a speed reduction gearbox and a distribution gearbox with two distribution gearbox output shafts allowing the screw shafts of the twin-screw extruder to be coupled thereto, wherein the speed change gearbox is arranged at a driving end, wherein the speed reduction gearbox couples the speed change gearbox to the distribution gearbox, wherein the speed reduction gearbox has precisely one speed reduction gearbox input shaft, the precisely one speed reduction gearbox input shaft having a first speed reduction gearbox gear and a speed reduction gearbox output shaft having a second speedreduction gearbox gear, the first speed reduction gearbox gear and the second speed reduction gearbox gear being in meshing engagement, wherein a speed change gearbox output shaft of the speed change gearbox gear is detachably connected to the speed reduction gearbox input shaft so that the speed change gearbox and the speed reduction gearbox are configured such as to be separable from each other, wherein a speed change gearbox housing of the speed change gearbox and a speed reduction gearbox housing of the speed reduction gearbox are configured such as to be separate from each other; and a drive motor coupled to the speed change gearbox.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) FIG. 1 shows a schematic diagram of a treatment installation for material treatment comprising a drive motor, a twin-screw extruder and an associated gearbox assembly according to a first exemplary embodiment;

(2) FIG. 2 shows a front view of the gearbox assembly in FIG. 1;

(3) FIG. 3 shows a schematic illustration of a releasable shaft connection of a speed change gearbox and a speed reduction gearbox of the gearbox assembly in FIG. 1;

(4) FIG. 4 shows a schematic diagram of a treatment installation for material treatment comprising a drive motor, a twin-screw extruder and an associated gearbox assembly according to a second exemplary embodiment; and

(5) FIG. 5 shows a schematic diagram of a treatment installation for material treatment comprising a drive motor, a twin-screw extruder and an associated gearbox assembly according to a third exemplary embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(6) In the following sections, a first exemplary embodiment of the invention will be described with reference to FIGS. 1 to 3. A treatment installation 1 comprises a drive motor 2 that drives, via a gearbox assembly 3, a twin-screw extruder 4 for rotation in the same direction. The drive motor 2 is coupled to the gearbox assembly 3 via a coupling 8. The treatment installation 1 is used for material treatment, in particular for the treatment of plastic material.

(7) The gearbox assembly 3 has a speed change gearbox 5 at a driving end A and a distribution gearbox 7 at an output end B, the gearboxes 5, 7 being mechanically connected, in other words coupled to each other, by means of a speed reduction gearbox 6. The gearbox assembly 3 has a gear ratio i.sub.G defined by an input drive motor speed n.sub.A and an output gearbox speed n.sub.B, with i.sub.G being such that i.sub.G=n.sub.A/n.sub.B>1.

(8) The speed change gearbox 5 is configured in a physically separated manner. To this end, the speed change gearbox 5 is configured such as to be separate from the speed change reduction gearbox 6, thus forming an individual gearbox module, in other words an individual gearbox unit. At the input end of the speed change gearbox 5, a drive shaft 10 of the drive motor 2 is detachably connected, via the coupling 8, to a speed change gearbox input shaft 11. To this end, a friction element 9 is arranged between a coupling element at the driving end, said coupling element being fastened to the drive shaft 10, and a coupling element at the gearbox end, said coupling element being fastened to the speed change gearbox input shaft 11, the friction element 9 being detachably connected to one of the coupling elements, in particular the coupling element at the gearbox end. The shaft connection between the drive shaft 10 and the speed change gearbox input shaft 11 can be separated by demounting the friction element 9. At the output end of the speed change gearbox 5, a detachable shaft connection 12 is formed that connects a speed change gearbox output shaft 13 of the speed change gearbox 5 to a speed reduction gearbox input shaft 14 of the speed reduction gearbox 6.

(9) The speed change gearbox 5 has a single-stage configuration and has a gear ratio i.sub.W defined by the input speed n.sub.A and an output speed n.sub.R. The gear ratio i.sub.W is such that i.sub.W=n.sub.A/n.sub.R1. Depending on what is required, the gear ratio i.sub.W is therefore greater or smaller than 1. The gear ratio i.sub.W is defined by a first speed change gearbox gear 15 disposed on the input shaft 11 and a second speed change gearbox gear 16 disposed on the output shaft 13. The gears 15, 16 are in meshing engagement and are in particular configured as spur gears. The speed change gearbox input shaft 11 is mounted, by means of radial bearings 17, 18, to a speed change gearbox housing 19 of the speed change gearbox 5 on both sides of the first gear 15. Correspondingly, the speed change gearbox output shaft 13 is mounted, by means of radial bearings 20, 21, to the speed change gearbox housing 19 on both sides of the second gear 16. The radial bearings 17, 18, 20 and/or 21 in particular serve to absorb radial forces, the radial bearings may however also be configured in such a way as to absorb axial forces.

(10) The speed change gearbox housing 19 is configured such as to be separate from a speed reduction gearbox housing 22 of the speed reduction gearbox 6. The speed change gearbox housing 19 is detachably connected to the speed reduction gearbox housing 22. To this end, the speed change gearbox housing 19 is provided with a connection portion 23. The connection portion 23 is configured as an annular flange arranged substantially concentrically to the output shaft 13. The connection portion 23 has a plurality of fastening holes 24 arranged around the output shaft 13. Through the fastening holes 24, fastening means 25, for instance screws, are guided, which are detachably secured to the speed reduction gearbox housing 22. Depending on the number and shape of the fastening holes 24, the speed change gearbox housing 19 can be secured to the speed reduction gearbox housing 22 in various angular positions a. The fastening holes 24 may for instance have the shape of a circle or of an elongated hole. The position of the input shaft 11 is changeable or adjustable depending on the angular position . In particular, the position of the input shaft 11 is adjustable in a horizontal x direction and/or a vertical y direction. For instance, FIG. 2 shows a first position x.sub.1, y.sub.1 and a second position x.sub.2, y.sub.2 of the input shaft 11 depending on the angular position .

(11) The speed reduction gearbox 6 is configured such as to be separate from the speed change gearbox 5 and the distribution gearbox 7. The speed reduction gearbox 6 therefore forms an individual gearbox module, in other words an individual gearbox unit. As already described above, the speed reduction gearbox input shaft 14 is connected to the speed change gearbox output shaft 13 by means of the detachable shaft connection 12. A speed reduction gearbox output shaft 26 is detachably connected to a distribution gearbox input shaft 28 by means of another detachable shaft connection 27. Furthermore, the speed reduction gearbox housing 22 is configured such as to be separate from a distribution gearbox housing 29 of the distribution gearbox 7. The speed reduction gearbox housing 22 is detachably connected to the distribution gearbox housing 29. To this end, fastening means 30, for instance screws, are used, which are easily accessible.

(12) The speed reduction gearbox 6 has a single-stage configuration and has a gear ratio i.sub.R defined by the input speed n.sub.R and an output speed n.sub.V. The gear ratio i.sub.R is such that i.sub.R=n.sub.R/n.sub.V>1. The gear ratio i.sub.R is defined by a first speed reduction gearbox gear 31 at the input end and a second speed reduction gearbox gear 32 at the output end. The gears 31, 32 are in meshing engagement and are in particular configured as spur gears.

(13) The speed reduction gearbox input shaft 14 is mounted to the housing 22 by means of radial bearings 33, 34 on both sides of the first gear 31. On a side remote from the distribution gearbox 7, the speed reduction gearbox output shaft 26 is mounted to the housing 22 by means of an axial bearing 35. Furthermore, the speed reduction gearbox output shaft 26 is mounted to the housing 22 by means of radial bearings 36, 37 on both sides of the second gear 32. The radial bearings 33, 34, 36 and/or 37 are in particular configured such as to absorb radial forces, they can however also be configured such as to absorb axial forces.

(14) The distribution gearbox 7 is configured such as to be physically separated from the speed reduction gearbox 6 and the twin-screw extruder 4. The distribution gearbox 7 therefore forms an individual gearbox module, in other words an individual gearbox unit. The distribution gearbox input shaft 28 is detachably connected to the output shaft 26 of the speed reduction gearbox 6 by means of the shaft connection 27. The distribution gearbox 7 is further provided with two distribution gearbox output shafts 38, 39 connected to screw shafts 42, 43 of the twin-screw extruder 4 by means of shaft connections 40, 41 that are in each case detachable.

(15) The distribution gearbox 7 has a gear ratio i.sub.V defined by the input speed n.sub.V and the output speed n.sub.B. The gear ratio i.sub.V is such that i.sub.V=n.sub.V/n.sub.B=1. The distribution gearbox input shaft 28 is formed in one piece with the distribution gearbox output shaft 38, with the shaft 28 or 38, respectively, thus being continuous. For power distribution, the input shaft 28 is provided with a first distribution gearbox gear 44 that engages a second distribution gearbox gear 45. The second gear 45 is disposed on a distribution shaft 46 the output end of which is provided with a third distribution gearbox gear 47. The third gear 47 engages a fourth distribution gearbox gear 48 disposed on the distribution gearbox output shaft 39. The gears 44, 45, 47, 48 are for instance configured as spur gears.

(16) The distribution gearbox input shaft 28 is mounted to the distribution gearbox housing 29 by means of two radial bearings 49, 50 on both sides of the first gear 44. Furthermore, the distribution gearbox output shaft 38 is mounted to the housing 29 by means of another radial bearing 51. The distribution shaft 46 is further mounted to the housing 29 by means of radial bearings 52 to 55, with the radial bearings 52, 53 being arranged on both sides of the second gear 45 while the radial bearings 54, 55 are arranged on both sides of the third gear 47. On a side remote from the twin-screw extruder 4, the distribution gearbox output shaft 39 is mounted to the housing 29 by means of an axial bearing 56. Furthermore, the distribution gearbox output shaft 39 is mounted to the housing 29 by means of two radial bearings 57, 58 on both sides of the fourth gear 48. The radial bearings 49, 50, 51, 52, 53, 54, 55, 57 and/or 58 are in particular configured such as to absorb radial forces, they can however also be configured such as to absorb axial forces.

(17) The shaft connection 12 is configured in such a way that each of the speed change gearbox output shaft 13 and the speed reduction gearbox input shaft 14 has an end region 59 provided with external teeth, said end regions being non-rotationally interconnected by means of a sleeve provided with internal teeth 60. The sleeve 60 is fixed in an axial direction relative to the shafts 13, 14 by means of a disk 61 provided with external teeth. To this end, the disk 61 is secured to the front end of one of the shafts 13, 14 and rotated relative to the sleeve 60 about an axis of rotation M of the shafts 13, 14. The rotation about the axis of rotation M causes the sleeve 60 to be clamped between the disk provided with external teeth 61 and the end regions 59 provided with external teeth in such a way that the sleeve 60 is secured in the axial direction. The disk 61 is fastened to the front end of one of the end regions 59 by means of fastening means 62, for instance screws. In FIG. 3, the disk 61 is for instance fastened to the speed change gearbox output shaft 13. The detachable shaft connections 27 and 40, 41 are configured correspondingly.

(18) The gearbox assembly 3 further comprises a lubrication device 63 comprising a lubricant pump 64 and a lubricant line 65. Starting from a lubricant reservoir not shown in more detail, the lubricant line 65 is in particular configured such as to form a cycle, the lubricant line 65 thus running to all lubrication spots of the gearbox assembly 3 before terminating in the lubricant reservoir again. The lubricant line 65 is only partly shown in FIG. 1.

(19) Between the speed change gearbox 5 and the speed reduction gearbox 6, the lubricant line 65 runs outside the housings 19 and 22 and is provided with a predetermined separation point 66. Correspondingly, the lubricant line 65 runs outside the housings 19 and 29 between the speed change gearbox 5 and the distribution gearbox 7 as well and is provided with another predetermined separation point 66. Furthermore, the lubricant line 65 runs outside the housings 22 and 29 between the speed reduction gearbox 6 and the distribution gearbox 7 and is provided with a predetermined separation point 67. The predetermined separation points 66, 67 are in particular configured as quick-release couplings that are self-sealing in the separated state and self-locking in the connected state. The lubricant reservoir is for instance formed in the speed reduction gearbox 6. The treatment installation 1 has a control device 68 for control thereof. The control device 68 is in particular used to actuate the drive motor 2. For this purpose, the gear ratios i.sub.R and i.sub.V are stored in the control device 68. To read the gear ratio i.sub.W into the control device 68, a reading device 69 is provided that is able to read out a coding element 70 disposed on the speed change gearbox 5. The coding element 70 is for instance readable optically or mechanically by means of the reading device 69. The reading device 69 is in signal communication with the control device 68 to which the gear ratio i.sub.W is provided.

(20) The treatment installation 1 has an auxiliary drive device 71 allowing the twin-screw extruder 4 to be emptied, the auxiliary drive device 71 being connected to the speed reduction gearbox input shaft 14 via a freewheel. To this end, the speed reduction gearbox input shaft 14 is guided out of the speed reduction gearbox housing 22 on a side remote from the speed change gearbox 5. In order to empty the twin-screw extruder 4, the auxiliary drive device 71 provides a high torque at a low speed. When the gearbox assembly is driven by means of the drive motor 2, the auxiliary drive device 71 is decoupled from the speed reduction gearbox input shaft 14 using the freewheel 72.

(21) The following sections describe the startup and operation of the treatment installation 1:

(22) In the operation of the treatment installation 1, the drive motor 2 drives the screw shafts 42, 43 of the twin-screw extruder 4 in the same direction, strictly speaking in the same direction of rotation. The drive motor speed n.sub.A is set, by means of the speed change gearbox 5, to a desired speed n.sub.R in accordance with the gear ratio i.sub.W. Since the gear ratios i.sub.R and i.sub.V are not changed, the screw shaft speed n.sub.S and the gearbox speed n.sub.B of the gearbox assembly 3 are adjusted via the gear ratio i.sub.W. For adjustment, the gear ratio i.sub.W can be selected such as to be greater or smaller than 1. The speed reduction gearbox 6 is used to reduce the input speed n.sub.R in such a way that the output speed n.sub.V is such that n.sub.V<n.sub.R. The distribution gearbox 7 distributes the driving power provided by the distribution gearbox input shaft 28 to the distribution gearbox output shafts 38, 39. Since the gear ratio i.sub.V=1, the input speed n.sub.V is equal to the output speed n.sub.B.

(23) In order to change the screw shaft speed n.sub.S in relation to the drive motor speed n.sub.A, the gear ratio i.sub.G of the gearbox assembly 3 is changed. This is done by replacing the entire first speed change gearbox 5 having the gear ratio i.sub.W by another second speed change gearbox having a different gear ratio. The second speed change gearbox ready to be installed is only indicated in FIG. 1 and designated by reference numeral 5, the second speed change gearbox having a gear ratio i.sub.W.

(24) In order to replace the speed change gearbox 5, the lubricant pump 64 is shut off, causing the lubricant to flow back into the lubricant reservoir, which is for instance formed in the speed reduction gearbox 6. The speed change gearbox 5 is therefore free of lubricants, thus allowing it to be demounted. In a second step, the shaft connection between the drive motor 2 and the speed change gearbox is separated. To this end, the friction element 9 is demounted, and the fastening means 25 are then detached so that the housings 19 and 22 are no longer connected to each other.

(25) The speed change gearbox 5 is now moved away from the speed reduction gearbox 6 in the axial direction, thus causing the shaft connection 12 to be separated. The shaft connection 12 is separated by removing the associated sleeve 60 from the speed reduction gearbox input shaft 14. The speed change gearbox 5 can now be removed by means of a lifting device not shown in more detail and replaced by the second speed change gearbox 5.

(26) The speed change gearbox 5 is now mounted in reverse order. To this end, the speed change gearbox 5 is moved, in a first step, towards the speed reduction gear 6 in the axial direction, causing the sleeve 60 arranged on the speed change gearbox output shaft 13 to be slid over the speed reduction gearbox input shaft 14. In a second step, the housings 19, 22 are connected to each other using the fastening means 25. When doing so, the connection portion 23 is mounted to the housing 22 in such a way that the speed change gearbox input shaft 11 is aligned coaxially with the drive shaft 10. Then a shaft connection is formed between the drive shaft 10 and the speed change gearbox input shaft 11 by mounting the friction element 9. The shaft connections thus formed connect the speed change gearbox 5 to the drive motor 2 and the speed reduction gearbox 6. Finally, the predetermined separation points 66, in other words the quick-release couplings 66, are connected again. In the meantime, the reading device 69 has read out the coding member 70 so as to determine the gear ratio i.sub.W, which was then transmitted to the control device 68. The control device 68 actuates the drive motor 2 depending on the gear ratio i.sub.W and adjusts the screw shaft speed n.sub.S.

(27) The speed change gearbox 5 can be replaced in a corresponding manner in the event of an upcoming maintenance or a defect. Due to the fact that the speed change gearbox 5 is configured as an individual gearbox module, in other words an individual gearbox unit, the treatment installation 1 has a high flexibility and productivity in the operation of the twin-screw extruder 4. Since the entire speed change gearbox 5 is replaced, this results in low downtimes and therefore in a high availability of the treatment installation 1.

(28) Furthermore, in the event of an upcoming maintenance and/or a defect, the speed reduction gearbox 6 and/or the distribution gearbox 7 being configured as separate gearbox modules, in other words as separate gearbox units, can be replaced as well by separating the respective shaft connections 12, 27, 40, 41 and by separating the predetermined separation points 66, 67 and housings 19, 22, 29, thus allowing downtimes to be reduced and the availability of the treatment installation 1 to be increased. Furthermore, the individual gearbox units 5, 6, 7 can be transported more easily.

(29) The following section describes a second exemplary embodiment of the invention with reference to FIG. 4. In contrast to the first exemplary embodiment, the speed change gearbox 5, the speed reduction gearbox 6 and the distribution gearbox 7 are arranged in a U-shaped configuration. In other words, the drive motor 2 and the twin-screw extruder 4 are arranged on the same side of the gearbox assembly 3. This facilitates the replacement of the speed reduction gearbox 6. Further details concerning the design and functioning of the treatment installation 1 can be found in the description of the first exemplary embodiment.

(30) The following section describes a third exemplary embodiment of the invention with reference to FIG. 5. In contrast to the preceding embodiments, the axial bearing 35 is arranged in the distribution gearbox 7. Further details concerning the design and functioning of the treatment installation 1 can be found in the descriptions of the preceding exemplary embodiment.

(31) Since the gearbox assembly 3 does not have switching stages, the gearbox assembly 3 has a low complexity so the costs are kept to a minimum. Due to its low complexity, the gearbox assembly 3 furthermore has a high reliability and therefore a high availability.

(32) Preferably, all bearings and gears in the gearbox assembly 3 are lubricated via pressure lines using oil as a lubricant. The lubrication device in particular has a central infeed and discharge spot. After being fed in, the flow of oil is distributed internally among the individual bearings and gears. At the transition to the speed change gearbox 5, the oil is fed from a pipe into a hose and then into an internal distribution system consisting of fixed pipes or fixed bores in the speed change gearbox 5. At the lowest point in the gearbox assembly 3, the oil is centrally recirculated back into the main oil reservoir of the gearbox assembly 3 via a passive outlet before being drawn into an oil treatment installation. The hoses at the connection points are provided with quick-release couplings that are easily separable for demounting, are self-sealing in the separated state and self-locking in the connected state, and are protected against unauthorized opening.