Linear drive and guide bearing

Abstract

Linear drive and guide bearing (1) for performing a relative linear movement of two machine components (5, 10), with - at least one linear motor (27) having at least one magnet (15) arranged on one of the machine components (5) and at least one coil (25) arranged on the other machine component (10) and operatively connected to the at least one magnet (15), wherein the at least one magnet (15) and the at least one coil (25) are configured to exert a mutual attraction force and at least a temporary relative movement towards each other, - at least one hydrostatic fluid bearing (30-1, 30-3) arranged on one of the two machine components (10) and operatively connected to the other machine component (5), wherein the hydrostatic fluid bearing (30-1, 30-3) exerts a repulsive force in the opposite direction to the attractive force, - wherein the two machine components (5, 10) each have a first virtual, mutually parallel plane (E1, E2) in which the linear motor (27) and the hydrostatic fluid bearing (30-1, 30-3) extend, forming a first bearing gap (H1), characterized in that - a second virtual plane (E3) inclined, preferably orthogonal, to the respective first virtual plane (E1, E2), in which at least one linear guide means (60) is formed, is provided, and - the first bearing gap (H1) formed between the two machine components (5, 10) has a height greater than 0 µm and less than or equal to 10 µm.

Description

[0001] The present invention relates to a linear drive and guide bearing according to the preamble of claim 1.

[0002] Linear drive and guide bearings for performing relative movement of two machine components are known in principle. They serve to reliably and precisely move, guide, and hold the two machine components, which may be part of a machine tool or machining center, in motion. The applicant for this patent offers a machining center comprising a generic linear drive and guide bearing under the registered German trademark KERN Pyramid Nano (official registration number 30676385), with which two machine components can be moved relative to each other at a distance of 20 µm or more.

[0003] From German patent application DE 10 2004 004 020 A1, a guide device with a linear motor is known, comprising a magnet arranged on one of the machine components and a coil arranged on another machine component and operatively connected to the magnet, wherein the at least one magnet and the at least one coil are configured to exert a mutual attraction force and a relative movement towards each other, at least temporarily. Furthermore, from the aforementioned patent application, a hydrostatic fluid bearing, supplied by a fluid, is known, arranged on one of the two machine components and operatively connected to the other machine component, wherein the hydrostatic fluid bearing exerts a repulsive force opposing the attraction force.The two machine components each have a first virtual, mutually parallel plane in which the linear motor and the hydrostatic fluid bearing extend, forming the first bearing gap.

[0004] A guide device with a linear motor and air bearings is known from US publication 4,985,651.

[0005] The object of the present invention is to provide a fluid-fed drive and guide bearing with which two machine components can be positioned and moved linearly relative to each other with even greater precision than in the prior art.

[0006] The problem is solved according to the invention by the features of claim 1. Further embodiments of the invention are set forth in the dependent claims.

[0007] Thus, the linear drive and guide bearing according to the invention for performing a relative linear movement of two machine components comprises at least one linear motor, which has at least one magnet arranged on one of the machine components and at least one coil arranged on the other machine component. In principle, the coil can be designed without a core. Advantageously, however, the coil includes a core, in particular a core formed with a ferrite, which allows for a comparatively simple design and particularly good technical performance of the coil. The magnet, preferably a permanent magnet, and the coil are operatively connected to each other and arranged such that they can exert a mutual attraction force and a relative movement with respect to each other, at least temporarily.

[0008] Furthermore, the linear drive and guide bearing according to the invention, for performing a relative linear movement of two machine components, comprises at least one hydrostatic fluid bearing arranged on one of the two machine components and operatively connected to the other machine component, and supplied by a fluid. This bearing is configured such that it exerts a repulsive force opposite to the attractive force, so that a first bearing gap can be formed between the two machine components. It is understood that the attractive force and the repulsive force are of equal magnitude if a first bearing gap of constant height is to be established between the two machine components, which are arranged to be movable relative to each other. The acceleration, speed, and position of a machine component in a feed direction can, in principle, be adjusted by controlling the current flowing through the aforementioned coil.The acceleration, speed, and position of the machine component perpendicular to the feed direction can, in principle, be adjusted by controlling or regulating the flow of the hydraulic current, and thus the flow of the fluid, through the hydrostatic fluid bearing. Alternatively or cumulatively, the height of the bearing gap, the acceleration, the speed, and / or the relative direction of movement of the two machine components can be easily controlled or regulated by appropriately adjusting the electric current flowing through the coil, which is also matched to the magnet.

[0009] The two machine components each have a first virtual, mutually parallel plane in which the linear motor and the hydrostatic fluid bearing extend, forming the first bearing gap. This ensures precise and parallel guidance of the two machine components during their relative movement.

[0010] The linear drive and guide bearing according to the invention is characterized, firstly, by the provision of a second virtual plane inclined to the first virtual plane, in which at least one linear guide element is formed. The corresponding angle of inclination can be any suitable value, in particular 15°, 30°, or 45°. It is particularly advantageous to provide a second virtual plane orthogonal to the respective first virtual plane, in which at least one linear guide element is formed. Thus, the angle of inclination is 90°, thereby advantageously achieving a restriction of the degrees of freedom of the two machine components.

[0011] Furthermore, the linear drive and guide bearing according to the invention is characterized in that the height of the first bearing gap of the linear drive and guide bearing according to the invention for performing a relative linear movement of two machine components is more than 0 µm and essentially 10 µm or less. In other words, if the height of the first bearing gap is designated by H1, essentially the following relationship applies: 0μm

[0012] ​Due to the proposed design of the linear motor as a synchronous linear motor and its operative connection with at least one hydrostatic fluid bearing, a linear drive and guide bearing with high efficiency and good thermal management is advantageously created, which also exhibits very high precision. The relative movement of the two machine components can be such that one of the two machine components moves while the other remains stationary, or that both machine components move simultaneously.In other words, it is advantageously provided that one machine component moves while the other machine component remains in its position, or that one machine component remains in its position while the other machine component moves relative to it, or that both the one machine component and the other machine component move relative to each other simultaneously.

[0013] According to a preferred embodiment, the linear guide element comprises at least one fluid bearing element and a magnetic bearing element that counteracts this fluid bearing element. This advantageously provides a simple and adjustable bearing arrangement for the linear drive and guide bearing according to the invention, enabling precise and easy guidance of the two machine components in two mutually orthogonal planes. It is understood that the opposing forces acting on the machine component(s) by the fluid bearing element and the magnetic bearing element are of equal magnitude in order to maintain the linear guide element in equilibrium.

[0014] A particularly simple design of a linear drive and guide bearing according to the invention is achieved when the fluid bearing means and the magnetic bearing means are arranged on one and the same machine component and are operatively connected to the other machine component.

[0015] According to a further preferred embodiment, the linear drive and guide bearing according to the invention, viewed in cross-section, has the structure disclosed below. It should be noted that the cross-section corresponds to a virtual cross-sectional surface through the device according to the invention, which is orthogonally oriented with respect to both the first virtual plane and the second virtual plane. One of the machine components thus has a first support surface, a second support surface spaced apart from it, and a first receiving area located between these. The other machine component, in contrast, has a first receiving section, a second receiving section spaced apart from it, and a second receiving area located between these.In the first mounting section, at least one hydrostatic fluid bearing opposite the first support surface is mounted; in the second mounting section, a second hydrostatic fluid bearing opposite the second support surface is mounted; in the first mounting section, at least one magnet is mounted, and in the second mounting section, at least one coil is mounted, with the magnet and the coil being positioned opposite each other. This advantageously creates a particularly precise and comparatively simple linear drive and guide bearing.

[0016] The first receiving area can be recessed relative to the first and / or second contact surface. This advantageously creates a channel in which fluid, particularly oil, escaping from the hydrostatic fluid bearing can collect. By appropriately designing the channel surface and / or providing an optional drain, this fluid can be easily removed from the magnet.

[0017] For the purpose of a particularly simple design of the linear drive and guide bearing according to the invention and its improved guiding precision, the machine component comprising the first receiving section and the second receiving section has a first projecting section and a second projecting section opposite the first projecting section. The fluid bearing means is arranged in the first projecting section. The magnetic bearing means is arranged in the second projecting section, with the two projecting sections being adjacent to the other machine component, forming a second bearing gap.

[0018] Advantageously, a particularly simple linear drive and guide bearing is created if the magnetic bearing element comprises a magnetic strip located on one machine component and a counter strip, preferably ferromagnetic, located on the other machine component, which are configured to exert a repulsive force on each other. It is understood, however, that alternatively or cumulatively, at least one variable or fixed electromagnetic means may be provided to adjust the required repulsive force.

[0019] According to a preferred embodiment, the fluid medium corresponds to one of the provided hydrostatic fluid bearings. In other words, the structure of a fluid medium can correspond to that of a hydrostatic fluid bearing, thereby advantageously reducing the manufacturing costs of the device according to the invention by means of a common parts strategy. It is understood that all fluid media and hydrostatic fluid bearings located in the linear drive and guide bearing according to the invention can also have an identical structure, thereby multiplying the aforementioned advantage.

[0020] The linear drive and guide bearing according to the invention is further characterized by at least one temperature control means. This makes it possible to temperature control, and in particular to cool, a single part, several parts, or all of the previously disclosed parts of the linear drive and guide bearing in such a way that its temperature-induced deformations can be compensated or reduced to an acceptable level. Advantageously, temperature control fluid-carrying lines can be provided in one or both machine components, on the linear motor, particularly on or in the area of ​​the coil and / or the magnet, in the area of ​​the hydrostatic fluid bearing, and / or in the area of ​​the fluid bearing element. Furthermore, it is advantageously possible to arrange at least one temperature measuring device at at least one of the previously disclosed locations.

[0021] Further features and advantages of the invention are illustrated in the accompanying, non-limiting embodiments of the present invention with reference to the accompanying, not-to-scale drawing. Fig. 1 a symbolic and simplified cross-sectional view through a linear drive and guide bearing according to the invention, Fig. 2 one to the in Fig. 1 shown embodiment alternative embodiment, and Fig. 3 a simplified perspective bottom view of a opposite in Fig. 1 shown machine component alternative machine component.

[0022] The in Fig. The linear drive and guide bearing 1 shown in Figure 1 according to the invention serves to reliably and precisely generate, guide, and stop a linear relative movement of two machine components 5, 10. The machine components 5, 10 can be part of, in particular, a machine tool or machining center (not shown here).

[0023] Again Fig. As can be seen from Figure 1, the lower machine component 5 has a first support surface 5-1, a second support surface 5-3 spaced apart from it, and a first receiving area 5-5 located between them. The latter is recessed relative to the two support surfaces 5-1 and 5-3 and forms a channel 7, the function of which will be explained later.

[0024] In contrast, this is in the Fig. 1. The upper machine component 10 is formed flat on the side facing the machine component 5 and has a first receiving section 10-1, a second receiving section 10-3 spaced apart from it, and a second receiving area 10-5 located between them. The first receiving section 10-1 is located opposite the first support surface 5-1, the second receiving section 10-3 is located opposite the second support section 5-3, and the second receiving area 10-5 is located opposite the first receiving area 5-5.

[0025] The linear drive and guide bearing 1 comprises a magnet 15, which, according to this embodiment, is designed as a substantially flat permanent magnet and is positioned in the first receiving area 5-5 by means of a carrier 20. At the point in the Fig. On the upper machine component 10, and opposite the magnet 15, is a coil 25 having a ferrite core (not shown) which is connected via an electrical connection 25-1 to electronics (not shown). The magnet 15 and the coil 25 attract the two machine components 5 and 10 by permanent magnetism. Furthermore, the coil 25 can be brought into operative contact with the magnet 15 by means of the electronics in order to form a linear motor 27 together.

[0026] To prevent a magnetically induced collision of the two machine components 5, 10, a first hydrostatic fluid bearing 30-1 is arranged on the first receiving section 10-1 and a second hydrostatic fluid bearing 30-3 is arranged on the second receiving section 10-3. These bearings exert a hydrostatic pressure on the first contact surface 5-1 and the second contact surface 5-3, respectively, through a fluid (not shown) acting on the fluid. This pressure counteracts the aforementioned magnetic attraction force. The fluid is pumped from a reservoir 45 by a pump 40 through a fluid line 50, via hydraulic resistors (not shown), to the two hydrostatic fluid bearings 30-1, 30-3. From there, it exits into a laterally sealed chamber (not shown) that is open towards the two receiving areas 5-1 and 5-3.Any leakage fluid (not shown) that escapes from the chamber is collected in channel 7 and can be returned to reservoir 45 via a leakage line 55 if necessary.

[0027] Through the interaction of the linear motor 27 and the hydrostatic fluid bearings 30-1, 30-3, a first bearing gap H1 can be set between the two machine components 5, 10 in the area of ​​the first receiving section 10-1 and the second receiving section 10-3, the height of which is 5 µm according to this embodiment. It is understood that, according to the invention, the height of the first bearing gap H1 can also be less than 5 µm, for example 3 µm, or greater, for example 6 µm, 7 µm, 8 µm, 9 µm or 10 µm.

[0028] It is readily apparent that this first bearing gap H1, which is very small compared to the prior art, is not easy to set and maintain. Therefore, it is provided that the two machine components 5, 10 each have a first virtual, mutually parallel plane E1 and E2, respectively, in which the linear motor 27 and the hydrostatic fluid bearings 30-1, 30-3 extend. In particular, this prevents a collision between the two machine components 5, 10 when they are set in motion or stopped relative to each other due to the activity of the linear motor 27. The movement itself is carried out with reference to Fig. 1, out of or back into the plane of the paper. In other words, the feed axis V of the machine component 10 is aligned orthogonally to the plane of the paper.

[0029] According to the embodiment shown here, the linear drive and guide bearing 1 is designed such that the machine component 10 moves relative to the machine component 5, while the latter remains stationary or is fixedly mounted on a component not shown here, in particular a machine stand.

[0030] The previously disclosed means enable the two machine components 5, 10 to be guided in the direction of the feed axis V and in the direction of the first gap H1. For the purpose of lateral guidance of the two machine components 5, 10, a first section 60-1 and a second section 60-3 spaced apart from it project from the machine component 10 in a second virtual plane E3 orthogonal to the respective first virtual plane E1, E2 in the direction of the machine component 5, such that a second bearing gap H2 is provided between these sections and the machine component 5.

[0031] At the one in the Fig. In the first section 60-1 shown on the left, there is a fluid bearing element 65 designed as a hydrostatic bearing, which interacts with the machine component 5 opposite it, separated by the bearing gap H2. For this purpose, the fluid bearing element 65 is connected to the pump 40 by means of a fluid line 70 and hydraulic resistors (not shown here), so that a repulsive mechanical force is generated between the first section 60-1 and the machine component 5. It should be noted that the fluid bearing element 65 can correspond to one of the hydrostatic fluid bearings 30-1, 30-3.

[0032] In the area of ​​the Fig. In the second section 60-3 shown on the right, there is a magnetic bearing element 75 which is also subject to a repulsive force relative to the machine component 5 in order to create a second bearing gap H2 between the two. For this purpose, a magnetic strip 75-1 is arranged on the machine component 5 and, opposite this on the second section 60-3, a ferromagnetic counter strip 75-3 is arranged. It is understood that the magnetic bearing element 75 can alternatively also be designed as an electromagnetic device.

[0033] By ensuring a suitable performance of the pump 40, positioning and geometry or design of the fluid bearing medium 65 in coordination with the magnetic repulsion force of the magnetic bearing medium 75, a very precise second bearing gap H2 can be set.

[0034] To further improve the dimensional accuracy of the linear drive and guide bearing 1, a temperature control device 80 is provided, which in the embodiment shown here comprises a plurality of channels 80-1 through which a cooling fluid (not shown) flows. The channels 80-1, fluidically connected to a temperature control system (not shown), are located in the machine component 10, the coil 25, the carrier 20, the machine component 5, and the first projecting section 60-1, in order to achieve a uniform temperature distribution across the linear drive and guide bearing. For the purpose of temperature measurement, a temperature measuring device 80-3 is housed in the coil 25. It is understood that, in particular, the number, positioning, and dimensions of the channels 80-1 may differ from the embodiment presented here.

[0035] In Fig. 2 is opposite to the one in Fig. One alternative embodiment of a linear drive and guide bearing 1 is shown. The one in the Fig. The right section of the machine component 5 has a recess 5-7, on the right side of which, also shown in this figure, a magnetic strip 75-1 is arranged. Furthermore, the second section 60-3, which has a counter strip 75-3, is located at least partially and freely movable in the recess 5-7. Unlike the one described with reference to Fig. In the embodiment shown in Figure 1, the magnetic strip 75-1 and the counter strip 75-3 are now designed to attract each other. Otherwise, the construction and function of the linear drive and guide bearing 1 correspond to that of the one shown in Figure 1. Fig. 1 embodiment shown.

[0036] One opposite the Fig. One alternative embodiment of a machine component 10 is in Fig. Figure 3 shows a perspective view from below. As can be seen, the machine component 10 and the first projecting section 60-1 are now formed as a single piece. The second projecting section 60-3 is not shown in this figure and can be mounted on a fastening section 10-7 located on the machine component 10.

[0037] On the underside of the machine component 10 and in its four corner regions, a first hydrostatic fluid bearing 30-1 and a second hydrostatic fluid bearing 30-3, respectively, are provided, all having the same design. A fluid bearing element 65 is arranged on the first projecting section 60-1, consisting of two spaced-apart hydrostatic fluid bearings 65-1 and 65-2, which in turn correspond to the first and second hydrostatic fluid bearings 30-1 and 30-2, respectively. As can be seen, the hydrostatic fluid bearings 30-1, 30-3, 65-1, and 65-2 extend in the same longitudinal direction, which is identical to the feed axis V or direction of movement of the machine component 10.

[0038] Unlike in Fig. Figure 1 shows the channels 80-1 of the temperature control medium 80 according to Fig. 2 not aligned in the direction of the feed axis V, but perpendicular to it and essentially parallel to the virtual plane E1. Reference symbol list 1 linear drive and guide bearing 5 Machine component 5-1 first contact surface 5-3 second support surface 5-5 first recording area 5-7 recess 7-channel 10 machine component 10-1 first recording section 10-3 second recording section 10-5 second recording area 10-7 Fastening section 15 Magnet 20 carriers 25 coil 25-1 electrical connection 27 Linear motor 30-1 first hydrostatic fluid bearing 30-3 second hydrostatic fluid bearing 40 pump 45 Reservoir 50 Fluid line 55 Leakage line 60 Linear guide device 60-1 first section 60-3 second section 65 Fluid storage media 65-1 hydrostatic fluid bearing 65-3 hydrostatic fluid bearing 70 Fluid line 75 Magnetic bearing materials 75-1 Magnetic strip 75-3 Counter strip 80 Tempering agents 80-1 channels 80-3 Temperature measuring instrument E1, E2 first virtual levels E3 second virtual level H1 first bearing gap H2 second bearing gap V feed axis

Claims

[1] Linear drive and guide bearing (1) for performing a relative linear movement of two machine components (5, 10), with - at least one linear motor (27) having at least one magnet (15) arranged on one of the machine components (5) and at least one coil (25) arranged on the other machine component (10) and operatively connected to the at least one magnet (15), wherein the at least one magnet (15) and the at least one coil (25) are configured to exert a mutual attraction force and at least a temporary relative movement towards each other, - at least one hydrostatic fluid bearing (30-1, 30-3) arranged on one of the two machine components (10) and operatively connected to the other machine component (5), wherein the hydrostatic fluid bearing (30-1, 30-3) exerts a repulsive force in the opposite direction to the attractive force, - wherein the two machine components (5, 10) each have a first virtual, mutually parallel plane (E1, E2) in which the linear motor (27) and the hydrostatic fluid bearing (30-1, 30-3) extend, forming a first bearing gap (H1), characterized by , that - a second virtual plane (E3) inclined, preferably orthogonal, to the respective first virtual plane (E1, E2), in which at least one linear guide means (60) is formed, is provided, and - the first bearing gap (H1) formed between the two machine components (5, 10) has a height greater than 0 µm and less than or equal to 10 µm. [2] Linear drive and guide bearing (1) according to claim 1, characterized by , that the linear guide means (60) has at least one fluid bearing means (65) and a magnetic bearing means (75) that counteracts it. [3] Linear drive and guide bearing (1) according to claim 2, characterized by, that the fluid bearing means (65) and the magnetic bearing means (75) are arranged on one and the same machine component (10) and are operatively connected to the other machine component (5). [4] Linear drive and guide bearing (1) according to any one of the preceding claims, characterized by, that one of the machine components (5), viewed in cross-section, has a first support surface (5-1), a second support surface (5-3) spaced apart from it, and a first receiving area (5-5) located between them, and that the other machine component (10) has a first receiving section (10-1), a second receiving section (10-3) spaced apart from it, and a second receiving area (10-5) located between them, wherein in the first receiving section (10-1) at least one first hydrostatic fluid bearing (30-1) opposite the first support surface (5-1), in the second receiving section (10-3) a second hydrostatic fluid bearing (30-3) opposite the second support surface (5-3), in the first receiving area (5-5) the at least one magnet (15) and in the second receiving area (10-5) the at least one coil (25) are received opposite the first receiving area (5-5). [5] Linear drive and guide bearing (1) according to claim 4, characterized by , that the first receiving area (5-5) is recessed compared to the first support surface (5-1) and / or the second support surface (5-3). [6] Linear drive and guide bearing (1) according to any one of claims 2 to 5, characterized by , that the machine component (10) comprising the first receiving section (10-1) and the second receiving section (10-3) comprises a first projecting section (60-1) in which a fluid bearing means (65) is arranged, and a second projecting section (60-3) opposite the first projecting section (60-1) in which a magnetic bearing means (75) is arranged, wherein the two projecting sections (60-1, 60-3) are adjacent to the other machine component (5) forming a second bearing gap (H2). [7] Linear drive and guide bearing (1) according to any one of claims 2 to 6, characterized by, that the magnetic bearing means (75) has a magnetic strip (75-1) located on one machine component (5) and a counter strip (75-3) located on the other machine component (10), which are arranged to exert a magnetic repulsion force on each other. [8] Linear drive and guide bearing (1) according to any one of claims 2 to 7, characterized by , that the fluid bearing means (65) corresponds to at least one hydrostatic fluid bearing (30-1, 30-3). [9] Linear drive and guide bearing (1) according to any one of the preceding claims, characterized by at least one tempering agent (80).

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