Vibration drive for a tamping unit for tamping a track

Abstract

The invention relates to a vibration drive (19) for a tamping unit (11) for tamping a track (4), comprising an eccentric (22) having a transmission device (21) mounted thereon for applying vibration to tamping tines (12), wherein the eccentric (22) is rotationally-locked and radially displaceably connected to a drive shaft (26) rotatable about an axis of rotation (56), and wherein the position of the eccentric (22) relative to the drive shaft (26) can be adjusted in the radial direction. Here, the drive shaft (26) is designed at least partially as a hollow shaft with at least one aperture (35) in the region of the eccentric (22), wherein a movable control shaft (33) with a slotted guide track (39) is arranged in the drive shaft (26), and wherein, for the radial adjustment of the eccentric (22), an actuating unit (36) which projects through the aperture (35) and bears against an inner surface (38) of the eccentric (22) is guided in the slotted guide track (39). When the control shaft (33) is adjusted, the actuating unit (36) slides in the slotted guide track (39) and displaces the eccentric (22) with respect to the drive shaft (26).

Description

[0001] VIBRATION DRIVE FOR A TUMBLING UNIT FOR TUMBLING A TRACK

[0002] The invention relates to a vibration drive for a tamping unit for tamping a track, comprising an eccentric with a transmission device mounted thereon for applying vibration to tamping picks, wherein the eccentric is rotationally locked and radially displaceable with a drive shaft rotatable about an axis of rotation and wherein the position of the eccentric relative to the drive shaft is adjustable in the radial direction.

[0003] A tamping unit is used to tamp the sleepers of a track bed embedded in ballast, ensuring that the track grid, consisting of rails and sleepers, is fixed in the desired position after lifting and aligning. During this process, vibrating tamping picks are inserted into the ballast bed on both long sides of a sleeper and aligned with each other. Initially, ballast is pushed into a cavity created by lifting the sleeper. After this filling, the ballast is compacted by the continuous vibration of the tamping picks, resulting in a durable sleeper support. For vibration application, swivel arms mounted on a tool carrier, with the tamping picks attached to them, are coupled to a vibration drive via auxiliary drives.

[0004] Due to high loads during the insertion and placement phases, the vibratory drive must meet special requirements. Continuous load changes occur during the insertion of the tamping picks into the ballast bed and the subsequent compaction of the ballast, placing stress on the vibratory drive. In particular, a hardened ballast bed generates high counterforces on the tamping picks, which are set into vibration by the vibratory drive. Even under such challenging operating conditions, the vibratory drive must maintain the required vibration of the tamping picks with a nearly constant vibration amplitude to ensure consistent tamping quality.

[0005] These requirements are met by a vibratory drive with a rotatable eccentric shaft. The respective auxiliary drive is mounted directly or indirectly on an eccentric, namely an eccentric section of the eccentric shaft. As the eccentric shaft rotates, the auxiliary drive transmits the circular motion of the bearing into an oscillating pivoting motion of the associated pivoting arm with the tamping picks. Concrete forces act back on the vibratory drive in a corresponding manner.

[0006] A vibration drive with adjustable vibration amplitude, such as that found in AT 517999 Al of fenbart, is advantageous. Here, the eccentric is mounted as a separate component on a drive shaft. Specifically, the eccentric is rotationally locked and radially displaceable from the drive shaft, with its position relative to the drive shaft adjustable in the radial direction by means of an adjusting device. In this way, the eccentricity of the eccentric can be set within a range between zero and a predetermined maximum value. The zero position is used, for example, when tamping picks are raised, to prevent disruptive vibrations and noise during the relocation of the tamping unit to the next threshold.The invention is based on the objective of improving the stability and adjustability of a vibration drive of the aforementioned type and, in particular, enabling its integration into an existing stuffing unit.

[0007] This problem is solved by the features of independent claim 1. Dependent claims specify advantageous embodiments of the invention.

[0008] According to the invention, the drive shaft is at least partially designed as a hollow shaft with at least one opening in the area of ​​the eccentric. A movable control shaft with a cam track is arranged in the drive shaft, and an actuating unit projecting through the opening and bearing against an inner surface of the eccentric is guided in the cam track for radial adjustment of the eccentric. When the control shaft is adjusted, the actuating unit slides in the cam track, which can also be referred to as a guide track. This cam guide is a positive guide that causes a change in the position of the actuating unit according to a predetermined shape and position of the cam track. The actuating unit, having changed its position, displaces the eccentric relative to the drive shaft, thereby changing the eccentricity of the eccentric accordingly.The positive guidance and mechanical coupling of the components ensure that the set eccentricity is maintained even under high counterforces. In addition to its robustness, the assembly is compact, allowing for easy integration into an existing tamping unit. The required space is no greater than that of a vibratory drive with a non-adjustable eccentric shaft. In a further advantageous embodiment, the actuating unit includes a rolling element, particularly a ball, guided in the cam track. This further increases stability and achieves particularly precise eccentricity adjustment.

[0009] Advantageously, the actuating unit comprises a piston that engages with the rolling element and rests against the inner surface of the eccentric. The piston bears against the eccentric over a flat surface. The rolling element also rests against a concave surface of the piston. Avoiding point or linear contact points reduces the stresses acting in the actuating unit and the eccentric, even with a constant pressure force.

[0010] Preferably, the cam track has a continuously varying depth relative to the surface of the control shaft. When the position of the control shaft changes relative to the drive shaft, the actuating unit moves within the cam track, with the changing depth causing a radial change in the position of the actuating unit. The actuating unit thus also moves the eccentric radially.

[0011] In an alternative configuration of the cam track with a constant depth, a change in the position of the control shaft, for example, causes the adjusting unit to shift axially. The opening in the drive shaft is designed as an axially oriented elongated slot. During an adjustment operation, the adjusting unit slides along an inclined section of the eccentric's inner surface, resulting in a radial adjustment of the eccentric. A corresponding adjustment can also be achieved by shifting the adjusting unit tangentially. In this case, the opening in the drive shaft is designed as a tangentially oriented elongated slot.

[0012] To further improve adjustability, the cam track is arranged in a helical shape, for example, by having a symmetry line of the cam track correspond to a segment of a helical curve. The cam track extends along the surface of the control shaft in both axial and tangential directions. This allows for a longer cam track with a constant control shaft diameter, resulting in shallower gradients along the cam track. During an adjustment operation, the control shaft is moved axially and simultaneously rotated about its axis of rotation. Due to the superimposed rotational movement, only a small stroke is required for axial adjustment of the control shaft.

[0013] For example, the stroke is in a range of 5 mm to 15 mm, preferably 10 mm. The actuating unit, held in the opening of the drive shaft and engaging in the cam track, provides positive guidance of the control shaft relative to the drive shaft. Thus, an actuating process can be carried out with both an axial actuator between the control shaft and the drive shaft and with a rotary actuator between the control shaft and the drive shaft.

[0014] Preferably, the eccentric on the control shaft is associated with two radially opposite cam tracks with actuating units guided therein. The depth profiles of the cam tracks and the radial extension of the actuating units are coordinated such that the actuating units bear against opposite inner surfaces of the eccentric in every position of the control shaft. With this double-acting actuating device, the eccentric can be actively reset to the zero position. In a simpler embodiment, the reset is achieved, for example, by means of a spring.

[0015] In a further improvement, the drive shaft in the eccentric area has a cross-section with parallel sliding surfaces, whereby the eccentric is guided radially displaceable on these sliding surfaces via inner surfaces. Specifically, the cross-section of the drive shaft in this area is square. This ensures both robust torque transmission and good displaceability of the eccentric on the drive shaft. Furthermore, such a drive shaft exhibits high bending stiffness and smooth running.

[0016] In an advantageous embodiment of the vibratory drive, in addition to the central eccentric, two further eccentrics are arranged radially displaceable on the drive shaft, with a fork-shaped transmission device mounted on these additional eccentrics. Thus, a central eccentric and two outer eccentrics are arranged along the drive shaft. Such a vibratory drive is coupled to opposing tamping picks via auxiliary drives and pivot levers as transmission devices. One of the auxiliary drives is mounted on the central eccentric by means of a ball joint, and the other auxiliary drive is mounted on the two outer eccentrics by means of a ball joint fork. This mounting arrangement ensures a symmetrical arrangement of the transmission devices without torsional loads.Such a vibration drive can be dimensioned with the same bearing dimensions and housing connections as a conventional vibration drive, so that it can be easily installed in an existing stuffing unit.

[0017] Advantageously, the drive shaft is mounted at two free ends in an eccentric housing, with one end connected to a rotary drive and the other end of the control shaft extending from the drive shaft and connected to an actuator. This arrangement allows for a compact design and optimized bearing support for both the drive shaft and the control shaft.

[0018] The actuator is preferably designed as a double-acting hollow piston hydraulic cylinder. The control shaft protruding from the drive shaft is coupled to the hollow piston in such a way that the control shaft, together with the hollow piston, is axially displaceable relative to the drive shaft. A cylinder housing is preferably connected to the eccentric shaft housing. This actuator enables precise adjustment of the control shaft and can be locked in a desired position by blocking the hydraulic lines. In this way, unwanted changes in the position of the control shaft due to reaction forces or vibrations are reliably prevented.

[0019] Advantageously, the hollow piston of the double-acting hollow piston hydraulic cylinder is rotatable, in particular by means of an axial bearing, mounted on the control shaft. An axial retainer and / or at least one axial bearing transmit an axial actuating force from the hollow piston to the control shaft. High positional accuracy is maintained even with the rotary decoupling.

[0020] In another embodiment, the actuator is designed as an electric motor, specifically a torque motor. In this case, changing the eccentricity is achieved by rotating the control shaft relative to the drive shaft. Once the eccentricity is set, the control shaft rotates synchronously with the drive shaft.

[0021] In every embodiment, the rotary drive is advantageously designed as an electric motor, in particular as a torque motor, wherein a rotor of the electric motor is connected to the drive shaft without its own bearings and wherein a stator of the electric motor is arranged in a motor housing connected to the eccentric housing. The electric motor can be operated with high efficiency and is precisely controllable. Compared to a hydraulic motor, it also offers smoother operation.

[0022] Preferably, the actuator and the rotary drive are coupled by means of a common control unit for coordinated control. As soon as the eccentricity is set to zero, the rotational speed is also reduced, resulting in an overall reduction in component stress and emitted noise. This enables the use of a tamping machine even in areas and at times of day with noise restrictions.

[0023] If the actuator is designed as an electric motor, it is operated in a torque-controlled manner. During normal operation without an actuation process, the torque is kept at almost zero, so that no relative movement occurs between the control shaft and the drive shaft. For an actuation process, torque is applied in one direction or the other. This results in a relative movement between the control shaft and the drive shaft, with the resulting radial displacement of the eccentric relative to the drive shaft. Advantageously, the control device is configured for speed-controlled operation of the rotary drive and for controlling the actuator as a function of a predetermined eccentricity. A predetermined vibration frequency determines the speed of the rotary drive.For example, the control unit includes a frequency converter connected to a supply voltage, which generates a predefined output frequency with a corresponding output voltage for the rotary drive. Furthermore, the control unit incorporates a relationship between the eccentricity to be set and a control angle or axial position of the control shaft. This relationship results from the arrangement of the drive shaft, the control shaft with its respective cam track, the respective actuator, and the respective eccentric. This ensures coordinated control of the rotary drive and the actuator.

[0024] The invention is explained below by way of example with reference to the accompanying figures. These show, in schematic representation:

[0025] Fig. 1 Tamping machine on a track;

[0026] Fig. 2 Stuffing unit in a side view;

[0027] Fig. 3 Stuffing unit in a front view;

[0028] Fig. 4 Vibration drive with a hollow piston

[0029] Hydraulic cylinder as actuator in a sectional view;

[0030] Fig. 5 Drive shaft in an oblique view;

[0031] Fig. 6 Control shaft with cam tracks;

[0032] Fig. 7 Control shaft according to Fig. 6 with rolling elements in a first end position; Fig. 8 Control shaft according to Fig. 6 with rolling elements in a second end position;

[0033] Fig. 9 Cross-section through control shaft, drive shaft, actuating units and eccentric in a position with maximum eccentricity of the eccentric;

[0034] Fig. 10 Cross-section according to Fig. 9 in a zero position of the eccentric;

[0035] Fig. 11 Sectional view of a vibration drive with electric actuator;

[0036] Fig. 12 Cross-section through control shaft, drive shaft, actuating units and eccentric with rollers as actuating units in a position with maximum eccentricity of the eccentric.

[0037] The tamping machine 1 shown in Fig. 1 comprises a machine frame 2, which is movable on rail carriages 3 on a track 4. This tamping machine 1 serves to restore the intended position of a track grid formed from rails 5 and sleepers 6, which is supported in a ballast bed 7. For lifting and lateral alignment, a lifting and alignment unit 8 is arranged on the machine frame 2, with a measuring system 9 continuously recording the actual position of the track grid. A tamping unit 11 arranged behind it with respect to a working direction 10 comprises tamping picks 12, which are immersed in the ballast bed 7 and aligned with each other during a tamping operation.

[0038] The tamping unit 11 is explained with reference to Figures 2 and 3. Each tamping pick 12 is mounted in a pick holder 13 of a swivel arm 14, which is pivotally mounted on a tool carrier 16 about a pivot axis 15. This tool carrier 16 is guided in a unit frame 17 and is height-adjustable by means of a height adjustment drive 18 so that the tamping picks 12 can be lowered into and raised again from the ballast bed 7.

[0039] During a tamping process, the tamping picks 12 are vibrated by means of a vibratory drive 19. For the application of vibration, each swivel arm 14 is connected to an auxiliary drive 20, which, as a transmission device 21, couples the associated tamping pick 12 to the vibratory drive 19. The respective auxiliary drive 20 is mounted on an eccentric 22 of the vibratory drive 19 and, during operation, transmits a circular motion of the eccentric 22 into an oscillating swivel motion and thus into a vibration of the associated tamping pick 12. In a variant not shown, the transmission device 21 comprises an eccentric arm that is mounted on the eccentric 22 and pivotally connected to the auxiliary drive 20.

[0040] As can be seen in Fig. 2, the two opposing pivot arms 14 with the tamping picks 12 form a tamping tool pair that can be lowered into the ballast bed 7 for tamping a sleeper 6. The auxiliary drives 20 of this tamping tool pair are preferably symmetrically connected to the vibratory drive. For this purpose, one auxiliary drive 20 is mounted with a pivot eye 23 on a central eccentric 22, and the other auxiliary drive 20 is mounted with a pivot fork 24 on two outer eccentrics 22 of the vibratory drive 19, as shown in Fig. 4. In a variant not shown, both auxiliary drives 20 are mounted with a pivot eye on their respective assigned eccentrics 22. Another variant not shown comprises two vibratory drives 19 for each tamping tool pair, each with only one eccentric 22. Each swivel arm 14 is assigned its own vibration drive 19, for example at the

[0041] Bearing point between swivel arm 14 and tool carrier 16 .

[0042] The vibration drive 19 shown in Fig. 4 comprises an eccentric housing 25 in which a drive shaft 26 is mounted. A free end of the drive shaft 26 projects from the eccentric housing 25 and is rotationally connected to a rotor 27 of an electric rotary drive 28. In this way, the rotor 27 and the drive shaft 26 are mounted together in the eccentric housing 25 by means of two rolling bearings 29. The rotary drive 28 is preferably a torque motor that provides sufficiently high torques even at low speeds. A stator 30 of the rotary drive 28 is arranged in a motor housing 31 connected to the eccentric housing 25.

[0043] Three eccentrics 22 are arranged side by side on the drive shaft 26, rotationally locked and radially displaceable by means of a radial guide having sliding surfaces 32. In Fig. 5, for clarity, the drive shaft 26 is shown with only one outer eccentric 22. The ball joint 23 is mounted on the middle eccentric 22, and the ball joint 24 is mounted on the two outer eccentrics 22, which are adjustable together. The middle eccentric 22 is arranged with a phase shift relative to the two outer eccentrics 22. With an advantageous phase shift of 180°, all eccentrics 22 are arranged on the same sliding surfaces 32 of the drive shaft 26, whereby during an adjustment operation, the middle eccentric 22 is displaced in one direction and the two outer eccentrics 22 are displaced in the other direction. In the case of a phase shift deviating from 180°, the mean eccentric 22 is arranged on its own sliding surfaces 32.Advantageously, the phase shift is adapted to an angle enclosed by the transmission devices 21, so that optimized mass balancing ensures smooth running of the vibration drive.

[0044] The drive shaft 26 is designed as a hollow shaft, at least in the area that does not project from the eccentric housing 25. In this area, a control shaft 33 is guided within the drive shaft 26, with an end section 34 of the control shaft 33 projecting from the drive shaft 26. Furthermore, sliding surfaces 32 for the radial guidance of the eccentrics 22 are arranged in this area. For radial displacement of the respective eccentric 22, an actuating unit 36 ​​is arranged in a respective opening 35. The respective opening 35 penetrates the wall of the drive shaft 26 between the cylindrical cavity in which the control shaft 33 is guided and an outer surface 37 of the drive shaft 26 below the associated eccentric 22. Preferably, the respective opening 35 is designed as a radial bore.

[0045] The actuating unit 36, guided in the respective opening 35, rests against an inner surface 38 of the associated eccentric 22. Furthermore, the actuating unit 36 ​​is guided in a cam track 39 of the control shaft 33. A movement of the control shaft 33 causes a relative displacement of the respective actuating unit 36 ​​along the associated cam track 39. In the examples shown, the respective cam track 39 has a continuously varying depth relative to a lateral surface 40 of the control shaft 33. Due to the radial guidance of the respective actuating unit 36 ​​in the drive shaft 26, a relative movement of the control shaft 33, and thus of the cam track 39, relative to the respective actuating unit 36 ​​causes a radial displacement 41 of this actuating unit 36 ​​and thus also of the eccentric 22 bearing against the actuating unit 36.

[0046] In the embodiment shown in Figures 4 to 10, the respective cam track 39 runs in the form of a helix. Thus, during an actuation process, an axial displacement 42 and a rotary movement 43 of the control shaft 33 relative to the drive shaft 26 are superimposed. An actuator 44 can therefore be designed as an axial drive and / or as a rotary drive. In the example shown in Figure 4, the actuator 44 is designed as a double-acting hollow piston hydraulic cylinder. The end section 34 is supported on a disk 45 of an axial bearing 46 designed as a double ball bearing. This axial bearing 46 allows rotation of the control shaft 33 relative to a hollow piston 47 of the hydraulic cylinder. A cylinder housing 48 is attached to the eccentric housing 25 and shields the hollow piston 47 from external influences by means of a cover 49. By pressurizing a respective pressure chamber 50, the hollow piston 47 transmits the axial displacement 42 to the control shaft 33.

[0047] Figures 5 to 7 show the control shaft 33 with four visible cam tracks 39. Each visible cam track 39 has a corresponding cam track 39 assigned to it on the non-visible section of the lateral surface 40. The sectional views (Figs. 9 and 10) show two corresponding cam tracks 39 arranged radially opposite each other on the control shaft 33. The radial extent 51 of each actuating unit 36 ​​is matched to the dimensions of the control shaft 33 with the cam tracks 39, the drive shaft 26, and the associated eccentric 22 such that the actuating units 36 bear against opposite inner surfaces 38 of the eccentric 22 in every position. In the example shown, each actuating unit 36 ​​comprises a piston 52, which rests against the associated inner surface 38 of the eccentric 22, and a rolling element 53, which is mounted in a convex surface of the piston 52 and guided in the associated cam track 39.The rolling element 53, in particular a ball, is thus in engagement with the piston 52 guided in the associated opening 35.

[0048] Figures 4 and 9 show the eccentrics 22 with a maximum eccentricity 54. With reference to Figures 9 and 10, the positioning process of each eccentric 22 is explained in detail. In Figure 9, it can be seen that the lower rolling element 53 has reached the lowest point of the associated cam track 39. The upper rolling element 53, on the other hand, is positioned at the opposite endpoint of the corresponding cam track 39 with the shallowest depth. Thus, the eccentric 22 reaches its upper end position with the maximum eccentricity 54.

[0049] To move the eccentric 22 into a zero position as shown in Fig. 10, an adjustment angle 55 is available. A change in the position of the control shaft 33 relative to the drive shaft 26 by this adjustment angle 55, together with the superimposed axial displacement 42, causes both actuating units 36, including the eccentric 22, to move into a lower end position. In this zero position, the eccentric 22, the drive shaft 26, and the control shaft 44 are concentric with respect to a common axis of rotation 56.

[0050] Preferably, the rotary drive 28 and the actuator 44 are connected to a common control unit 57. This allows for coordinated adjustment of the vibration frequency and vibration amplitude. To change the vibration frequency, the rotational speed of the rotary drive 28 is adjusted accordingly. The control of the actuator 44 determines the vibration amplitude. In this way, the tamping picks 12 can be subjected to different vibrations, with the vibration parameters such as frequency and amplitude being adapted to the respective conditions of the ballast bed 7. In particular, a control algorithm is stored in the control unit 57, by means of which the control of the actuator 44 is carried out depending on a predetermined eccentricity 54.

[0051] An alternative example is shown in Figures 11 and 12. Here, the respective cam track 39 runs along a circumference of the cylindrical surface 40 and has no axial component. The respective actuating unit 36 ​​is designed as a roller 58, which is guided in the corresponding opening 35 of the drive shaft 26 and in the corresponding cam track 39 of the control shaft 33. Continuously varying depths of the corresponding cam tracks 39, the respective roller diameters 51, and the dimensions of the drive shaft 26, the control shaft 33, and the eccentric 22 are coordinated such that, in every control shaft position, both radially opposite rollers 58 bear against the corresponding inner surfaces 38 of the eccentric 22 (Fig. 12).

[0052] A change in position is achieved by rotating the control shaft 33 relative to the drive shaft 26. For this purpose, the actuator 44 is designed as an electric motor, specifically a torque motor (Fig. 11). The actuator 44 and the rotary drive 28 are controlled synchronously by means of the common control unit 57. When the respective eccentric 22 is in a fixed position, both shafts 26 and 33 rotate synchronously, with the rotary drive 28 being speed-controlled and the actuator 44 being torque-controlled. In the eccentric position with maximum eccentricity 54 (Fig. 12), the actuator 44 can be used as a supplementary drive to increase the torque applied by the rotary drive 28. The torque component supplied by the actuator 44 is then transmitted from the control shaft 33 to the drive shaft 26 via the actuating units 36.To achieve the zero position of the respective eccentric 22, the control shaft 33 is braked relative to the drive shaft 44. In doing so, the actuator 44 generates a small torque in the opposite direction of rotation of the drive shaft 26 through appropriate control by means of the control device 57.

[0053] In this embodiment, both the rotary drive 28 and the actuator 44 are electrically operated, resulting in high efficiency. This is particularly advantageous for electrically powered tamping machines 1. Such a tamping machine 1 comprises a current collector 59 and preferably an electrical storage device 60 to supply, among other things, the rotary drive 28 and the actuator 44 with electrical energy. A travel drive 61 is also designed as an electric drive. Only the linear drives, such as the respective height adjustment drive 18 and the respective auxiliary drive 20, are connected to a hydraulic system with an electrically operated hydraulic pump. In the first embodiment according to Fig. 4, the actuator 44 is also connected to this hydraulic system.

[0054] The combination of the electrically operated tamping machine 1 with the adjustable vibration drive 19 offers the advantage that the machine 1 operates with high efficiency without

[0055] It can be operated with low pollutant emissions and low noise levels. This allows, for example, the operating hours and the associated closure times of track 4 to be shifted to nighttime hours in residential areas.

Claims

Patent claims 1. Vibration drive (19) for a tamping unit (11) for tamping a track (4), comprising an eccentric (22) with a transmission device (21) mounted thereon for applying vibration to tamping picks (12), wherein the eccentric (22) is rotationally locked and radially displaceable with a drive shaft (26) rotatable about an axis of rotation (56), and wherein the position of the eccentric (22) relative to the drive shaft (26) is adjustable in the radial direction, characterized in that the drive shaft (26) is at least partially designed as a hollow shaft with at least one opening (35) in the area of ​​the eccentric (22), that a movable control shaft (33) with a cam track (39) is arranged in the drive shaft (26), and that for radial adjustment of the eccentric (22) a cam track projecting through the opening (35) and attached to an inner surface (38) of the eccentric (22) adjacent control unit (36) is guided in the side track (39).

2. Vibration drive (19) according to claim 1, characterized in that the actuating unit (36) comprises a rolling element (53) guided in the cam track (39), in particular a ball.

3. Vibration drive (19) according to claim 2, characterized in that the actuating unit (53) comprises a piston (52) which engages with the rolling element (53) and bears against the inner surface (38) of the eccentric (22).

4. Vibration drive (19) according to one of claims 1 to 2, characterized in that the cam track (39) has a continuously changing depth relative to a cylindrical surface (40) of the control shaft (33).

5. Vibration drive (19) according to one of claims 1 to 4, characterized in that the cam track (39) is arranged in the form of a helix.

6. Vibration drive (19) according to one of claims 1 to 5, characterized in that the eccentric (22) on the control shaft (33) is associated with two radially opposite cam tracks (39) with actuating units (36) guided therein, and that the depth profiles of the cam tracks (39) and the extent (51) of the actuating units (36) in the radial direction of the control shaft (33) are coordinated such that the actuating units (36) bear against opposite inner surfaces (38) of the eccentric (22) in every position of the control shaft (33).

7. Vibration drive (19) according to one of claims 1 to 6, characterized in that the drive shaft (26) in the area of ​​the eccentric (22) has a cross-section with sliding surfaces (32) aligned parallel to each other and that the eccentric (22) is guided radially displaceable with inner surfaces on these sliding surfaces (32).

8. Vibration drive (19) according to one of claims 1 to 7, characterized in that, in addition to the eccentric (22), two further eccentrics (22) are arranged radially displaceable on the drive shaft (26) and that a fork-shaped transmission device (21) is mounted on the further eccentrics (22).

9. Vibration drive (19) according to one of claims 1 to 8, characterized in that the drive shaft (26) is mounted with two free ends in an eccentric housing (25), that one end is connected to a rotary drive (28) is connected and that at the other end the control shaft (33) protrudes from the drive shaft (26) and is connected to an actuator (44).

10. Vibration drive (19) according to claim 9, characterized in that the actuator (44) is designed as a double-acting hollow piston hydraulic cylinder.

11. Vibration drive (19) according to claim 10, characterized in that the hollow piston (47) of the double-acting hollow piston hydraulic cylinder is rotatably mounted on the control shaft (33), in particular by means of axial bearings (46).

12. Vibration drive (19) according to claim 9, characterized in that the actuator (44) is designed as an electric motor, in particular as a torque motor.

13. Vibration drive (19) according to one of claims 9 to 12, characterized in that the rotary drive (28) is designed as an electric motor, in particular as a torque motor, that a rotor (27) of the electric motor is connected to the drive shaft (26) without its own bearings and that a stator (30) of the electric motor is arranged in a motor housing (31) connected to the eccentric housing (25).

14. Vibration drive (19) according to one of claims 9 to 13, characterized in that the rotary drive (28) and the actuator (44) are coupled with a common control device (57) for coordinated control.

15. Vibration drive (19) according to claim 14, characterized in that the control device (57) is configured for speed-controlled operation of the rotary drive (28) and for controlling the actuator (44) depending on a predetermined eccentricity (54).

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