Abstract
The invention relates to a machining device (1), in particular a CNC machining device, for machining preferably planar workpieces (W) that are preferably composed of wood, wood material, plastic, and/or glass at least in parts, comprising: a machining assembly, which has a dynamic element; a first guide assembly, by means of which the machining assembly can be moved in a spatial direction; and at least one vibration-damping device. Vibrations of the dynamic element (3) can be passively damped by means of the at least one vibration damper device.
Claims
1. A machining device, in particular a CNC machining device for machining preferably plate-shaped workpieces which are preferably made at least in sections of wood, wood material, synthetic material and/or glass, comprising: a machining aggregate having a dynamic element which preferably comprises a rotating tool spindle; a first guide assembly by means of which the machining aggregate can be moved in a spatial direction; and at least one vibration-damping device, wherein by means of the at least one vibration-damping device, vibrations of the dynamic element can be passively damped.
2. The machining device according to claim 1, wherein the at least one vibration-damping device is provided on the side of the first guide assembly facing the dynamic element or on the first guide assembly.
3. The machining device according to claim 1, wherein the at least one vibration-damping device is configured in the form of a vibration-absorbing device which comprises at least one damping element, one auxiliary mass and one elastic support member.
4. The machining device according to claim 3, wherein the elastic support member carries the damping element and the auxiliary mass, the elastic support member preferably being directly secured to the dynamic element or to the first guide assembly.
5. The machining device according to claim 1, wherein the one damping force of the at least one damping element directly acts on the dynamic element or the damping force of the at least one damping element indirectly acts on the dynamic element.
6. The machining device according to claim 1, wherein the at least one damping element is a hydraulic shock absorber, a mechanical shock absorber, an eddy-current damper, an electro-mechanical converter material or a hydraulic damping gap.
7. The machining device according to claim 1, wherein the first guide assembly comprises a guide device which is preferably configured in the form of a linear guide, the guide device preferably comprising a guide assembly to which the machining aggregate is secured in order to be movable in a spatial direction, and the vibration-damping device being provided on the guide assembly.
8. The machining device according to claim 1 wherein the vibration-damping device is integrated into the tool spindle of the machining aggregate, the tool spindle having a cylinder-shaped inner part and a hollow cylinder-shaped outer part, the outer part being mounted on the inner part, the outer part corresponding to the auxiliary mass and containing the damping element, the damping element preferably being configured in the form of a hydraulic damping gap.
9. The machining device according to claim 1, wherein the one mass of the auxiliary mass and/or the damping characteristics of the damping element and/or a rigidity of the elastic support member is/are adjustable, in particular, corresponding to the present machining parameters and/or the tool used and/or the measured vibration data.
10. The machining device according to claim 1 wherein the at least two vibration-damping devices are provided which have two different directions of action which are on a shared plane, the two vibration-damping devices preferably being arranged around the dynamic element.
11. The machining device according to claim 1 wherein the three vibration-damping devices are provided which have three different directions of action and are on two intersecting planes, the three vibration-damping devices preferably being arranged around the dynamic element.
12. A method for operating a machining device, in particular the machining device according to claim 1, wherein by means of the method, vibrations of a dynamic element of a machining aggregate occurring during the machining of a workpiece are passively damped by means of a vibration-damping device.
13. The method according to claim 12, wherein the method further comprises: determining machining parameters such as, for example, feeding speed, cutting speed, cutting depth, cutting force, rotational speed of the tool, type of tool, etc., and/or detecting vibrations occurring by the dynamic element, preferably by means of vibration sensors detecting optimal setting parameters of the vibration-damping device such as, for example, the mass of the auxiliary mass, damping characteristics of the damping element, rigidity of the elastic support member, etc.; and adjusting the optimal setting parameters of the vibration-damping device.
14. The method according to claim 13, wherein the determination of the optimal setting parameters of the vibration-damping device occurs on the basis of the determined machining parameters and/or the determined occurring vibrations, the determined machining parameters and/or the determined occurring vibrations preferably being compared with empirically determined values and/or values determined by means of simulations and being determined corresponding to the optimal setting parameters.
15. The method according to claim 13, wherein the adjustment of the optimal setting parameters occurs manually, motorized or electro-mechanically.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] FIG. 1 schematically shows the basic principle of a vibration absorber damping system according to an embodiment of the present invention,
[0034] FIG. 2 shows a perspective representation of one embodiment of a machining aggregate of a machining device according to the present invention,
[0035] FIG. 3 schematically shows a first embodiment of a vibration-damping device for a machining device according to the present invention,
[0036] FIG. 4 schematically shows a second embodiment of a vibration-damping device for a machining device according to the present invention,
[0037] FIG. 5 schematically shows a third embodiment of a vibration-damping device for a machining device according to the present invention, and
[0038] FIG. 6 schematically shows a fourth embodiment of a vibration-damping device for a machining device according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] In the following, preferred embodiments of the present invention are described with reference to the accompanying drawings. Further variants and modifications of individual features cited in this context can each be combined with one another in order to form new embodiments.
[0040] FIG. 1 schematically shows the basic principle of a vibration absorber damping system according to an embodiment of the present invention. In FIG. 1, the reference number (100) represents the first guide assembly (5) which is shown as a static element to simplify the illustration. A swinging mass (102) is elastically suspended on the rigid element (100). The elastic elements (101) thereby correspond to the existing elasticity of the suspension of the mass (102). The mass (102) corresponds to the dynamic element (3) or the vibration exciter. At the vibrating mass (102), an auxiliary mass damper (HMD) or a vibration absorber/damping system according to the present invention is provided. The vibration absorber/damping system has an auxiliary mass (105) which is secured to the vibrating mass (102) by means of an elastic element (103), corresponds to the support member (9). Furthermore, the vibration absorber/damping system has a damper (104) which corresponds to the damping elements (7). The spring constant of the elasticity (101) is considerably higher than the spring constant of the elastic element (103). Consequently, the mass (102) is relatively rigidly secured to the static element (100) and on the other hand, the auxiliary mass (105) is relatively softly secured to the vibrating mass (102) by which the auxiliary mass (105) can be decoupled from the critical vibrations (frequencies) of the vibrating mass (102). Accordingly, the damper (104) stays at its place when viewed relative to the vibrating mass (102), and can thereby exert a damping force onto the vibrating mass (102).
[0041] FIG. 2 shows a perspective representation of one embodiment of a machining aggregate of a machining device according to the present invention. In the following, an embodiment of the present invention is described by way of example using a CNC machining device as a specific example of a machining device. As already mentioned previously, this can also, however, be machining aggregates of other machining devices such as, for example, pass-through machines. As shown, a machining device (1) generally has a machining aggregate (2) which comprises a tool spindle (4) which can accommodate a desired tool such as, for example, a milling tool, a drill, a sanding head, etc. The assembly of the machining aggregate (2) which rotatably accommodates and comprises the tool spindle (4) is called dynamic element (3) below since this assembly is significantly responsible for the generation and introduction of vibrations into the machining device (1). The dynamic element (3) is also often designated as a vibration exciter.
[0042] Vibrations can be caused by the rotation of the tool spindle (4) together with the tool, for example, due to an unbalance at the tool spindle (4) or the tool owing to changing loads on the tool during the machining of a workpiece and the like.
[0043] As is also revealed by FIG. 1, the CNC machining device has a first guide assembly (5) to which the machining aggregate (2) is secured and by means of which the machining aggregate can be moved in a spatial direction. The shown guide assembly (5) is referred to as the first guide assembly since the machining aggregate is directly secured to it without the interposition of a further guide assembly. As a rule, the first guide assembly (5) carries out a vertical movement, which allows the tool to be advanced to the workpiece to be machined. In the shown embodiment example, the dynamic element (3) comprises the tool spindle (4), a bearing of the tool spindle, a gear and a drive unit. The vibration-damping device (6) is realized such that the elastic support member (9) is configured in the form of a holding bracket which surrounds the dynamic element (3) in the horizontal plane and is secured to a guide carriage (11) of the guide assembly (5). Since the holding bracket is only formed using a thin sheet without any reinforcements, the holding bracket (elastic support member (9)) has a sufficiently high elasticity in order to largely decouple from the dynamic element (3), the auxiliary mass (8) which is arranged at the front side of the holding bracket centrally to the dynamic element (3). I.e., a propagation of the critical vibrations of the dynamic element (3) to the auxiliary mass (8) is prevented as best as possible. However, when determining the elasticity of the elastic support member (9) a compromise must, however, be found between sufficiently high elasticity for vibration decoupling dynamic element (3)auxiliary mass (8), and a sufficiently high rigidity of the elastic support member (9) to suppress a reverberation of the elements of the vibration-damping device (9) during the movement (acceleration-braking) of the machining aggregate. Therefore, there is also the possibility to form the holding bracket more rigidly and to instead provide an elastic element for vibration decoupling between the holder console and the guide carriage. The critical vibration (critical frequency) is understood to be the natural frequency of the basic machine (e.g. base frame with guide assemblies) under which a resonance could occur in the basic machine and thus an increase in vibration could build up in the basic machine.
[0044] The auxiliary mass (8) is constructed modularly, i.e. the auxiliary mass (8) consists of individual weight plates that can be modularly secured to the holding bracket in order to adjust the mass of the auxiliary mass in accordance with the operating parameters and/or the measured vibration data.
[0045] In the embodiment shown in FIG. 1, only one vibration-damping device (6) with a horizontal direction of action is provided. I.e. the damping elements (7) of the vibration-damping device (6) act in the horizontal direction. As shown in FIG. 1, the exemplary vibration-damping device (6) has two damping elements (7) provided on two opposite sides of the holding bracket and thus exert a damping force on the dynamic element (3) from two opposite directions.
[0046] In the following, different embodiments of the vibration-damping device (6) of the present invention in its basic structure will be explained by means of schematic illustrations that are shown in FIGS. 3 to 6.
[0047] FIG. 3 schematically shows essentially the same design as already described in detail in FIG. 1. In this embodiment, the elastic support member (9) is attached to the guide carriage (11) of the guide assembly (5) and decouples the auxiliary mass (8) from the dynamic element (3). As shown in FIG. 2, it is also possible to directly secure the damping elements (7) to the auxiliary mass (8) or to mount them in it. The damping elements (7) can engage each component of the dynamic element (3) (vibration exciter), with it being preferred that the damping elements (7) directly engage on the bearing of the tool spindle in order to form the passive damping even more directly.
[0048] FIG. 4 shows a further embodiment of the vibration-damping device (6) according to the present invention. In this embodiment, in contrast to the embodiment shown in FIG. 3, the elastic support member (9) is directly secured to the dynamic element (3) which enables a more compact construction, yet a decoupling of the auxiliary mass (8) from the critical vibrations of the dynamic element (3) is made more difficult.
[0049] FIG. 5 shows another embodiment of the vibration-damping device (6). In the present case, the vibration-damping device (6) is not formed around the dynamic element (3) as in the above-described embodiments which enables the damping forces of the damping elements (7) to directly engage the dynamic element (3), but rather it is entirely integrated or built on to the guide carriage (11). As revealed by FIG. 5, this offers the advantage that the vibration-damping device can be formed extremely compactly. Further, the decoupling of the auxiliary mass (8) from the critical vibrations of the dynamic element (3) is relatively simple. As shown, in this case, the auxiliary mass (8) can be arranged vibrating between the two damping elements (7) and fixed to the guide carriage (11) only by means of the elastic support member (9). In turn, the damping elements (7) are connected with the guide carriage by means of a receiving bracket and thereby indirectly damp critical vibrations of the dynamic element (3) before they propagate to other components of the machining device (basic machine).
[0050] In turn, FIG. 6 shows another embodiment of the vibration-damping device (6) of the present invention. As is visible from FIG. 6, in accordance with this embodiment, the vibration-damping device (6) can be completely integrated into the dynamic element (3), in particular directly into the tool spindle (4). The tool spindle (4) is thereby formed from two elements, a cylinder-shaped inner part (12) and a hollow cylinder-shaped outer part (13), with the outer part (13) being mounted on the inner part (12) and corresponds to the auxiliary mass (8). As shown, the damping element (7) or the damping elements (7) are integrated into the outer part (13) preferably distributed equally in the circumferential direction at the outer part (13). Owing to the limited installation space, it is therefore ideal, as shown, to configure the damping element (7) in the form of a hydraulic damping gap. The damping gap has a damping effect due to fluid friction. Since the outer part (13) as well as the bearing of the outer part (13) on the inner part (12) is relatively soft, and the outer part (13) is weakened further by the hydraulic damping gap, the outer part (13) can easily deform elastically under vibration excitation by the inner part (12) whereby the fluid present in the damping gap is moved, and thereby performs friction work which dampens the occurring vibrations. Further with this embodiment, the outer part (13) can be provided with a reservoir (not shown) in which the provided fluid can be displaced in order to increase the moving amount of fluid and to thereby increase the damping performance. The hydraulic damping gap is preferably formed relatively narrow and long in order to encourage the fluid friction.
