Damping of Vibrations of a Machine

Abstract

A device for damping vibrations of a machine, in particular for damping vibrations of a machine tool, wherein the device includes a first linear motor primary part, a pendulum mass, mounted via at least one supporting sheet-metal assembly provide a relative motion of the pendulum mass along the first linear motor primary part, a first linear motor secondary part fastened to the pendulum mass such that the pendulum mass is actuated via the first linear motor primary part to dampen vibrations of the machine, a second linear motor primary part, and a second linear motor secondary part fastened to the pendulum mass such that the pendulum mass is additionally actuated via the second linear motor primary part to dampen vibrations of the machine so as to achieve an especially compact device that makes it possible to dampen vibrations of machines, in particular machine tools, effectively and without maintenance.

Claims

1.-13. (canceled)

14. A device for damping of vibrations of a machine, comprising: a first linear motor primary part; a pendulum mass mounted via at least one supporting sheet metal assembly such that a relative movement of the pendulum mass along the first linear motor primary part is performable; a first linear motor secondary part fastened to the pendulum mass such that the pendulum mass is actuatable via the first linear motor primary part to damp vibrations of the machine; a second linear motor primary part; and a second linear motor secondary part fastened to the pendulum mass such that the pendulum mass is additionally is actuatable via the second linear motor primary part to dampen vibrations of the machine.

15. The device as claimed in claim 14, further comprising: a position detection system which detects a relative position of at least one linear motor secondary part in relation to a respective linear motor primary part.

16. The device as claimed in claim 15, wherein the position detection system evaluates a magnetization of at least one of the linear motor secondary parts for position detection.

17. The device as claimed in claim 14, wherein a first air gap between the first linear motor primary part and the first linear motor secondary part differs from a second air gap between the second linear motor primary part and the second linear motor secondary part.

18. The device as claimed in claim 15, wherein a first air gap between the first linear motor primary part and the first linear motor secondary part differs from a second air gap between the second linear motor primary part and the second linear motor secondary part.

19. The device as claimed in claim 16, wherein a first air gap between the first linear motor primary part and the first linear motor secondary part differs from a second air gap between the second linear motor primary part and the second linear motor secondary part.

20. The device as claimed in claim 17, wherein the first air gap differs from the second air gap such that a force of attraction always acts against the supporting sheet metal assembly.

21. The device as claimed in claim 14, wherein the pendulum mass is arranged between the linear motor primary parts.

22. The device as claimed in claim 14, further comprising: a controller which actuates at least one of the linear motors such that the pendulum mass counteracts vibrations of the machine.

23. The device as claimed in claim 14, further comprising: at least one end position buffer.

24. The device as claimed in claim 14, further comprising: a guide facility configured to prevent contact between the linear motor parts.

25. The device as claimed in claim 14, further comprising: a casing; wherein at least a part of the linear motor parts and the pendulum mass are arranged within the casing.

26. The device as claimed in claim 14, wherein a maximum dimension of the device amounts to at most 1/10.sup.th of a maximum dimension of the machine.

27. The device as claimed in claim 26, wherein the maximum dimension of the device is between arrange of at least 20 cm and not more than 80 cm.

27. The device as claimed in claim 14, wherein the device dampens vibrations of a machine tool.

28. The device as claimed in claim 26, wherein the maximum dimension of the device amounts to at most 1/10.sup.th of a maximum dimension of a machine tool.

29. A machine tool having at least one tool and also the device for damping vibrations as claimed in claim 14.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The invention will be described and explained in greater detail below with reference to the exemplary embodiments shown in the figures, in which:

[0022] FIG. 1 shows a device for damping of vibrations of a machine in accordance with the invention;

[0023] FIG. 2 shows a device in cross-section in accordance with the invention;

[0024] FIG. 3 shows a supporting sheet metal assembly in detail in accordance with the invention; and

[0025] FIG. 4 shows a machine, in particular a machine tool, having a device for damping of vibrations of the machine in accordance with the invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0026] FIG. 1 shows a compact device D for damping vibrations of a machine 1, in particular for damping vibrations of a machine tool. To this end, the device D has a first linear motor LMP1, LMS1, with a first linear motor primary part LMP1 and a first linear motor secondary part LMS1 as well as a second linear motor LMP2, LMS2 with a second linear motor primary part LMP2 and a second linear motor secondary part LMS2. The two linear motor secondary parts LMS1, LMS2 are connected in the device to a pendulum mass PM, which can perform a relative movement in relation to the linear motor primary parts LMP1, LMP2. The linear motor secondary parts LMS1, LMS2 are able to be integrated into the pendulum mass PM. The linear motor secondary parts LMS1, LMS2 in this case are formed in this embodiment as arrangements of permanent magnets, for example.

[0027] This makes possible the use of a position detection system POS, which directly evaluates the magnetization of the first linear motor secondary part LMS1 and establishes from this the relative position X of the linear motor secondary part LMS1 or of the pendulum mass PM in relation to the linear motor primary part LMP1. Both linear motor secondary parts LMS1, LMS2 are fastened to the pendulum mass PM. As a result, only a position detection system POS can be used for the relative positions X of the two linear motors. In this case, the pendulum mass PM is supported for the most compact and maintenance-free possible support via supporting sheet metal assemblies 40. Here, the supporting sheet metal assemblies 40 have supports 42 and also metal pendulum sheets 41, which are clamped into the support 42. For reasons of stability it is very advantageous to provide at least one linear motor LMP1, LMS1, LMP2, LMS2 for the use of supporting sheet metal assemblies 40, which exerts a force against the supporting sheet metal assemblies 40, because the supporting sheet metal assemblies 40 are preferably configured to accommodate tension forces. With a single linear motor LMP1, LMS1, LMP2, LMS2, the space between the two supporting sheet metal assemblies 40 would remain unused. It is thus advantageous to fill this volume with a further linear motor LMP1, LMS1, LMP2, LMS2. The further advantage is also produced that the upper linear motor exerts a force against the lower linear motor on the pendulum mass PM and partly balances out the tensile force of the linear motor again. The pendulum frequency of the device D is essentially produced from the length of the supporting sheet metal assemblies 40 and the resulting tension force. For the application as vibration damper it is advantageous for the pendulum frequency to lie as low as possible. The upper linear motor LMP1, LMS1 reduces the inherent frequency of the pendulum or of the pendulum mass PM, because it partly compensates for the tensile force of the lower linear motor LMP2, LMS2. A complete compensation for the force of attraction of the two linear motors LMP1, LMS1, LMP2, LMS2 is unwanted, because this could give rise to an unwanted state of uncertainty. The gravitational force is to be taken into account during this dimensioning, but is rather small when compared to the forces of attraction of the linear motors LMP1, LMS1, LMP2, LMS2. The device D can be used at any angle of inclination and even rotated by 180 degrees. The linear motors LMP1, LMS1, LMP2, LMS2 are in a position to compensate for the gravitational force which would move the pendulum mass PM out of the linear motors LMP1, LMS1, LMP2, LMS2. This could be parameterized accordingly in a control device.

[0028] In order to enable the device D to be used in the most flexible manner possible and to be protected from outside influences, the device has a casing C. This makes possible a separate and independent positioning of the device D on a machine 1. It is however also conceivable for the machine 1 to have a corresponding device D without the device needing a casing C. For example, a recess can already be provided in the machine 1 for the device D. Here, the device D has a maximum dimension D.sub.max. In this case, the maximum dimension D.sub.max is the dimension that extends in the direction of the relative position X.

[0029] In order to make the compact arrangement depicted in FIG. 1 even more compact, it is possible to provide the pendulum mass PM with end position buffers END. These end position buffers END prevent a hard impact of the pendulum mass PM on the casing C or on the machine 1, such as when the supply voltage fails or when another error is present.

[0030] The arrangement shown in FIG. 1 is shown schematically and, for the sake of clarity, has not been made as compact as if it were a real device. Here, the linear motors LMP1, LMS1, LMP2, LMS2 could entirely fill the space available for them and at least one of the linear motors LMP1, LMS1, LMP2, LMS2 could extend completely along the maximum dimension D.sub.max within the casing C, here. Even without a casing C it is desirable to fill out the installation space as completely as possible.

[0031] FIG. 2 shows a cross-section through a device D in a casing C and uses the reference characters from FIG. 1. A guide facility FV, FVN is to be seen in this figure, which in this case is formed as two groove tongues FV, which each engage in a groove FVN of the pendulum mass PM. The guide facility FV, FVN in this case is formed overall such that a tilt over of the pendulum mass PM is prevented such that the linear motor secondary parts LMS1, LMS2 come into contact with the linear motor primary parts LMP1, LMP2. Because of the strong forces of attraction between the linear motor primary and linear motor secondary parts LMP1, LMS1, LMP2, LMS2 the tilt over would be an undesired effect and is effectively prevented by the guide facility FV.

[0032] FIG. 3 shows a supporting sheet metal assembly 40 in detail. The corresponding reference characters are used in a similar way to FIG. 1. The pendulum mass PM is fastened to the lower support 42, which is connected by a metal supporting sheet 41 to a support 42 fastened above it. Here, the upper support 42 can be fastened directly to a casing C, can be formed as a part of the casing C and/or can be fastened directly to a machine 1. Furthermore, the lower of the two supports 42 is deflected by a deflection A.sub.max. This deflection A.sub.max should represent the maximum deflection that occurs during operation of the pendulum mass PM. It can further be seen that the supports 42 each have a clamping area 420 and also a bending motion link 421. In this case, the clamping area 420 is to be understood as the area in which the metal supporting sheet 41 is fastened. This can not only be done by clamping, e.g., via bolts or screws, but also by further conventional fastening measures or combinations thereof. The bending motion link 421 is the area of the support 42, in which the metal supporting sheet 41 can bend furthest without plastic deformation and thus the movement of the pendulum mass PM is only made possible at all therewith. Also shown is the free length L, which represents the actual vibrating length and thus has an influence on the inherent frequency of the arrangement. The radii R shown are intended to show the curvature of the bending motion links 421. This curvature enables it to be controlled by the construction of the support 42 that the metal supporting sheet 41 does not deform outside the predeterminable requirements. These predeterminable requirements can involve maximum bending strains, for example, which can arise from the bending radius. It is desirable in particular that the strains that occur in the metal supporting sheet 41, remain below the fatigue strength strain of the metal supporting sheet 41.

[0033] FIG. 4 shows a machine 1, in this case, for example, a machine tool with a tool T, which generates vibrations in the portal arrangement of the machine 1, for example. Also to be seen is the device D, which damps these unwanted vibrations. The device D in this figure has a maximum dimension D.sub.max and the machine 1 in this figure has a maximum dimension 1.sub.max. Here, it is conceivable that the device D only has a fraction of the maximum dimension 1.sub.max of the machine 1. As a result of the inventive combination of features, this makes possible an especially compact and yet despite this maintenance-free structure of the device D for damping of vibrations of the machine 1.

[0034] In summary, the disclosed embodiments of the invention relate to a machine tool and a device D for damping of vibrations of a machine 1, in particular for damping of vibrations of a machine tool. In order to achieve an especially compact device D, which makes possible an effective and maintenance-free vibration damping of machines, in particular of machine tools, a device is provided that has a first linear motor primary part LMP1, a pendulum mass PM, which is supported via at least one supporting sheet metal assembly 40 in such a way that a relative movement of the pendulum mass PM along the first linear motor primary part LMP1 is able to be performed, a first linear motor secondary part LMS1, which is fastened to the pendulum mass PM such that the pendulum mass is able to be actuated via the first linear motor primary part LMP1 to damp vibrations of the machine, a second linear motor primary part LMP2 and a second linear motor secondary part LMS2, which is fastened to the pendulum mass PM such that the pendulum mass PM is able to be actuated additionally via the second linear motor primary part LMP1 to damp vibrations of the machine 1.

[0035] Thus, while there have been shown, described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.