Compact roller bearing unit with direct drive for rotary tables with high-precision axial / radial runout and method for controlling the concentricity

Abstract

The invention relates to a roller bearing unit with a direct drive for rotary tables with high-precision axial / radial runout and a method for controlling the concentricity. The object of the invention is to create a roller bearing unit with a direct drive for rotary tables with high-precision axial / radial runout and a method for monitoring and controlling the concentricity in real time, which enables an adjustment movement to increase the concentricity of the output shaft and creates a novel system of micromechanics. According to the invention, a multi-dimensional high-precision measuring system (9) is arranged at the shaft end (5) of a shaft (4). This high-precision measuring system (9) enables precise measurement of the concentricity deviation of the shaft (4), either in real time or intermittently. A cam ring measuring system (11) is arranged on a motor housing washer (25) as a further measuring system, which measures and displays the shifting of a specially designed cam ring (8). The cam ring (8) is connected to a cam ring motor (21), which can control and rotate it from the outside, so that it can be adjusted adaptively and in a defined and up-to-date manner while constantly evaluating the measurement results, which are determined and displayed by the cam ring measuring system (11), and generates a precisely definable tilting movement of the shaft (4) in the axial bearing region.

Description

[0001] Compact roller bearing unit with direct drive for rotary tables with high-precision

[0002] Axial / radial runout and methods for controlling concentricity

[0003] The invention relates to a compact roller bearing unit with direct drive for rotary tables with high-precision axial / concentric runout with centric guidance of the cylindrical rollers and high-precision alignment of the cylindrical rollers for manufacturing accuracies in the nanometer range and a method for controlling the concentricity.

[0004] Such axial-radial roller bearings for high-precision rotary tables are required for the very precise and axis-centered support of direct drives with cantilevered rotors, whose output shafts must generate hardly any pulsations or thermal drift in the nanometer range. New applications are opening up, particularly for innovative sensor and actuator technology in conjunction with small-scale computers, such as lens grinding machines in the optical industry or angle measuring tables in metrology. The requirements for further miniaturization of general actuator and sensor technology are increasing in line with this. With the increasing miniaturization of manufactured parts, the manufacturing tolerance is also decreasing from the micrometer range to the nanometer range. In addition to absolute manufacturing accuracies, the geometric and positional accuracies of miniature components, for example, are also increasing.Manufacturing technologies in mechanics will therefore be subject to extremely high precision requirements in the future. Accuracies in the sub-micrometer range for three-dimensional components can sometimes only be achieved with 5-axis machining centers. Surface roughnesses of Ra = 0.02 pm can generally only be achieved economically using special machining processes such as grinding, turning and milling. Multi-axis machine tools are therefore subject to the highest demands in terms of rigidity, accuracy and temperature stability. The rotary axes with rolling bearings used replace hydrostatic rotary axes. Setting steps of 0.02 (20 nanometers) in the individual axes are necessary to achieve the required targets. With new multi-dimensional angle measuring systems, it is possible to record not only the rotary movement but also the tilting movement of the axis of a rotary table in the nanometer range.

[0005] Well-known rotary table bearings are axisymmetric bearings with races for the

[0006] Constructed of cylindrical rollers. The technical solution according to DE 10 2008 017 457 A1 describes a corresponding axial-radial roller bearing for rotary tables. It is constructed from an inner ring section, which supports and is connected to the actual rotary table. The corresponding outer ring section is connected to a base frame and coupled to an axially acting damping element. The damping only acts in one load direction. The inner ring section has a U-shaped cross-section. The outer ring section engages with the inner ring section and is supported on both sides by an axial bearing. Both the inner and outer ring sections are rotatably mounted in the radial direction via a radial bearing. The axial and radial bearings themselves are designed as cylindrical roller bearings. This bearing arrangement is intended to absorb both the applied axial and radial loads as well as the respective tilting moments.Although both bearings are clearance-free and have a defined preload, they are only suitable to a limited extent for high-precision rotary tables in the nanometer range. The installed components, such as the shaft and housing, influence the accuracy and rigidity of the bearing in the nanometer range. This creates joints and screw planes, which all have a negative effect on the axial runout and perpendicularity of the bearing. During operation, the running accuracy of the bearing changes, i.e. the radial and axial runout, as well as the wobble of the output shaft, increases. With longer operating times at higher speeds, particularly when operated with a direct drive, the thermal behavior of the axial-radial bearing becomes crucial for its running accuracy. Due to the different heating of the inner ring and the outer ring, the radial and axial running surfaces change differently. As a result of the thermally induced different expansion, the preload also changes in an indefinable way.This changing preload leads to waviness of the axial running surfaces in the nanometer range and to running pulsation of the cylindrical rollers, and in extreme cases even to premature bearing failure. While thermal behavior can be improved by, for example, implementing effective oil circulation cooling, this involves considerable additional effort. Furthermore, the application possibilities of such bearings suffer.

[0007] There are also other technical solutions for high-precision rotary table bearings, which consist of two combined axial angular contact ball bearings. These bearings feature corresponding raceway geometries on the inner and outer rings, on which the balls roll, each with a contact angle of 60°. This type of rolling bearing has the advantage that they can be preloaded to a higher degree and lead to less expansion of the two bearing rings when heated. However, overall, such bearings have lower axial / radial rigidity and, consequently, lower tilting stiffness. Therefore, they are also not sufficiently suitable for high-precision rotary table bearings in the nanometer range. The potential for the rolling elements to run into the ball tracks can lead to a loss of preload and a reduction in accuracy. In general, such ball bearings are not crash-resistant and therefore not suitable for use in the nanometer range.Due to the lack of crash safety and the limited service life, ball bearing rotary table bearings are only available to a limited extent.

[0008] Another rotary table bearing is known from DE 10 2012 221 725 A1, in which the inner ring and outer ring are supported by two rolling bearings with different contact angles. These are usually an axial roller bearing and an angular contact bearing. The axial bearing is preferably designed as a cylindrical roller bearing. The advantage of this design is that any change in the diameter of the inner ring and outer ring, particularly due to different heating of the two components, does not immediately result in an identical change in preload. However, this design is also not suitable for the desired high precision in the nanometer range. The individual bearing rings and joints weaken the bearing assembly. They create compliance and waviness in the bearing rings at the screw connection points and are therefore generally unsuitable for use in the nanometer range.The radial ball raceways of these rotary table bearings are not permanently crash-resistant in the narrow contact area, thus limiting their service life. Manufacturing the contact radii of the ball raceway with the axial roller raceway with axial rib guidance in the nanometer range significantly limits current manufacturing capabilities in the nanometer range. The rotary table bearing described, consisting of rollers and ball raceway, therefore only meets applications in the micrometer range, within a few thousandths of a millimeter.

[0009] DE 10 2012 206 667 B4 discloses an axial-radial bearing comprising a double-acting axial bearing and a radial guide bearing for supporting a directly driven axis of a machine table, in particular of a machine tool. A two-part inner ring is arranged opposite a rotatable outer ring, and two radially distributed rows of bores for securing the inner ring to a machine table are formed in the inner ring. The multiple screw fastening of the inner ring in two circumferential rows directly on the machine table is intended to achieve particularly high axial and tilting rigidity. However, this bearing design is not suitable for bearing arrangements with accuracies below one micrometer.

[0010] DE 10 2006 028 972 A1 describes a spindle unit with an adjustable work spindle that is mounted so that it can rotate about its longitudinal axis during operation. A complex motorized adjustment unit automatically and controllably adjusts the work spindle relative to the bearing housing during operation. For this purpose, a long, rotatable inner sleeve is arranged eccentrically within a rotationally fixed outer sleeve. The inner sleeve can also rotate relative to the outer sleeve. A tubular extension acts as an extension of the inner sleeve, via which the adjustment movement is generated by a servomotor located inside the spindle unit. Furthermore, an additional clamping device is provided to secure the inner sleeve so that it can no longer move relative to the outer sleeve. A suitable angle measuring system is also provided to determine the adjustment.In a second design, an intermediate sleeve is also eccentrically arranged and rotatable. This adjustment device is used to adjust a work spindle, including the tool mounted on it, or to align the work spindle relative to another work spindle. However, with such a non-bearing eccentric, fine adjustment down to the nanometer range is not possible. Furthermore, this technical solution results in increased frictional torque during operation. It is therefore not suitable for high-precision adjustment in the nanometer range.

[0011] The invention is based on the object of creating a compact, short roller bearing unit with direct drive for rotary tables with highly accurate axial / concentric runout and a method for monitoring and controlling concentricity in real time. This method enables an adjustment movement on the rotary axis of a roller bearing unit to increase concentricity and thus also the manufacturing accuracy with the same output shaft, even after running-in of a roller bearing unit, realizes a novel micromechanics down to accuracies significantly below 50 nm, enables precise guidance with minimal wear within a defined speed range, is also usable for conventional machine tools, and also generates material-saving and energy-efficient effects. The invention is achieved with the features of the first and ninth patent claims. Further advantageous embodiments are described in the dependent claims.The compact roller bearing unit 1 is connected to a direct drive 2 for driving a rotary table. The roller bearing unit 1, with high-precision axial / concentricity in the nanometer range, is designed particularly for absorbing axial and radial loads. According to the invention, a multi-dimensional high-precision measuring system 9, consisting of several radially distributed high-precision measuring heads and a shaft end measuring ring 10, which maps the concentricity of the shaft end 5 in the high-precision measuring heads, is arranged on a measuring system disk 12 at the shaft end 5 of a shaft 4. This multi-dimensional high-precision measuring system 9 enables the precise measurement of the concentricity deviation of the shaft 4, either in real time or in a timed manner. It can detect and display concentricity deviations in the nanometer range.A cam ring measuring system 11, consisting of at least one cam ring measuring head and a cam ring measuring ring 24, is arranged on a motor housing disk 25 as a further measuring system. This cam ring measuring system measures and displays the adjustment of a specially designed, ground cam ring 8 mounted on the shaft 4. The motor housing disk 25 is connected to a cam ring motor 21, which can control and rotate the cam ring 8 from the outside. The specially ground and adjustable cam ring 8 is mounted and guided internally in the roller bearing unit 1 on the shaft 4 via one or more staggered radial cylindrical roller rows 16 and externally via a cylindrical roller row 15, which can be designed as cylindrical roller rows or as pairs of cylindrical roller rows, directly in the bearing housing 18 of the roller bearing unit 1 without raceways and in the bearing housing 18.The specially ground, rotatably adjustable cam ring 8 is directly connected to a rotor 19 of a cam ring motor 21 arranged inside the bearing housing 18, so that it can be adjusted in a defined manner by means of the cam ring motor 21 with constant evaluation of the measurement results which are determined and displayed by the cam ring measuring system 11.

[0012] In a second embodiment, the cam ring 8 can additionally be designed with a separate adjustment device that can be adjusted manually from the outside via one or more locking bores 23 by means of one or more locking pins 27. A design of the compact roller bearing unit 1 according to the invention is also possible in which only manual adjustment is provided and no cam ring motor 21 is arranged. However, this simpler, cost-effective variant is only useful for special applications. The radial cylindrical roller rows 16 or radial cylindrical roller row pairs 16 and the cylindrical roller row for the cam ring outer bearing 15 are each set with differently defined bearing preloads so that the adjustment movement of the shaft 4 actually enables a precisely defined linear, high-precision bearing movement across the bearing center of the shaft 4 in the machining area.

[0013] For special applications of the innovative compact roller bearing unit 1, it is possible to design the cam ring 8 with two complementary double cams. In this configuration, it is supported by two spaced-apart cylindrical roller rows 15 in the bearing housing 18. The double cams allow for play-free clamping.

[0014] The adjustable cam ring 8 in the compact roller bearing unit 1 is ground so that the cam ring radii 26 of the cam ring 8 follow a staggered, individually adapted Archimedean spiral up to 180 degrees. However, depending on the application, the cam ring radii 26 can be redirected to follow individually different curves and be designed accordingly.

[0015] It is advantageous if, in the compact roller bearing unit, the bearing preload of the radial cylindrical roller row(s) or cylindrical roller row pairs 15 for the cam ring 8 is up to a maximum of 10 micrometers and the coaxial cam ring 8 is designed to be radially movable within this preload.

[0016] Furthermore, in the compact roller bearing unit 1, the bearing preload of the radial cylindrical roller rows 16 or cylindrical roller row pairs 16 is set to a maximum of half a preload between 3 and 5 micrometers.

[0017] It may also be advantageous for the manually or motor-adjustable cam ring 8 of the compact roller bearing unit 1 to be deformed or tensioned in the nanometer range in order to improve the inner diameter of the cam ring in its deviation from the circle (roundness) without significantly limiting the overall rigidity. In a further variant, the cam ring 8 of the compact roller bearing unit 1 can be designed with the same coaxially aligned curve profile on the inner and outer diameters for adjustment in the nanometer or micrometer range.

[0018] Only through these measures is a maximum tension of cam ring 8 relative to the bearing housing 18 achieved. When adjusting, it must be ensured that only the cam ring 8 is deformed within certain predetermined limits.

[0019] As a rule, for a high-precision measurement of the concentricity deviation of the compact roller bearing unit 1, it is sufficient to arrange four measuring heads distributed within the multi-dimensional high-precision measuring system 9. However, it is also possible to arrange up to eight measuring heads within the multi-dimensional high-precision measuring system 9, whereby additional axial displacements of the shaft end 5 can then also be measured, evaluated, and taken into account during operation.

[0020] For individual applications, the method for controlling the concentricity deviation of a compact roller bearing unit 1 can be carried out both by motor and by hand if the cam ring 8 is designed both with motorized adjustment by means of a cam ring motor 21 and with adjustment via simultaneously arranged plug-in bores 23 and by means of plug-in pins 27.

[0021] The solution according to the invention makes it possible for the first time not only to adjust the accuracy but also to adjust the bearing preload with high precision after the compact roller bearing unit 1 has been run in. With motor-driven cam adjustment, the accuracy is adjusted either continuously or intermittently. This is possible because both the externally applied radial load and the possible compliance of the roller tension can be measured, evaluated, and adjusted directly in real time for the first time. With manual adjustment, the manual rotary movement of the cam track or cam ring 8 is adjusted directly. The concentricity can also be visualized during adjustment. The multi-dimensional high-precision measuring system 9 can visualize and control the concentricity in a CNC control system, especially in real time operation.The advantage of the solution according to the invention over other known externally acting bearing adjustments is that a large adjustment torque of up to approximately 5000 Nm can be exerted directly at the shaft end. The solution according to the invention makes it possible to tilt the shaft 4 of the rotary axis in its axial bearings or the work table connected to the roller bearing unit 1 precisely in the micrometer range as well as in the nanometer range, i.e. to significantly improve the concentricity properties. The rotary axis is also designed as a measuring axis, which is constantly monitored during the production process. The output shaft is thus adjusted and readjusted in a type of linear movement of the shaft via the axis center, whereby a tilting movement of the shaft 4 occurs in the axial bearing area.

[0022] In principle, it is generally also possible to provide two adjustable cam rings 8. This complex solution improves the overall rigidity of the roller bearing unit 1. The same effect can also be achieved by dimensioning the cam ring 8 wider. A wider cam ring 8 is accordingly mounted on the shaft 4 via more rows of cylindrical rollers or pairs of rows of cylindrical rollers between the bearing housing 18 and the cam ring 8. A coaxial cam ring 8 with harmonious inner and outer raceways also increases the rigidity of the cam drive. A basic prerequisite for this is also a high rigidity of the bearing housing 18.

[0023] The essential advantage of the solution according to the invention compared to other known externally acting bearing adjustments is that a low adjustment torque of the cam ring motor 21 in the roller bearing unit 1 can enable both a wide adjustment range and a large adjustment torque directly at the shaft end 5 to approximately 5000 Nm, ie a minimal adjustment torque generates a maximum tilting moment of the output shaft via the cam design and the preload of the bearings.

[0024] The invention will be described in more detail below in an embodiment with reference to Figures 1 to 3.

[0025] Fig. 1 shows a roller bearing unit 1

[0026] Fig. 2 shows a simple design of a roller bearing unit 1 with manual adjustment Fig. 3 shows a preferred cam design for the cam ring 8

[0027] Fig. 4 shows a cross section through a roller bearing unit in the area of ​​the cam ring 8 Fig. 5 shows the linear movement of the shaft end with two different motors Fig. 1 shows a longitudinal section through a roller bearing unit 1 according to the invention. The direct drive 2 for the roller bearing unit 1 is a synchronous motor on the drive shaft

[0028] 17 is arranged within a motor housing 3. The direct drive 2 is mounted on the bearing housing

[0029] 18 suitable (usually screwed). In order to improve the rigidity of the roller bearing unit 1, the bearing housing 18 is very solid. An axial bearing shoulder 13 is attached to the motor housing for the axial bearing of the shaft 4 and is supported on the bearing housing 18. The shaft collar 6 is tilted with the shaft 4 within these axial rollers. Two axial rows of cylindrical rollers 14 are arranged to the left and right of the shaft collar 6 so that the shaft 4 is mounted between the axial bearing shoulder 13 and the bearing housing 18. Two rows of cylindrical rollers 16 are arranged for the radial bearing of the shaft 4. These rows of cylindrical rollers 16 for the shaft bearing are only slightly preloaded with a half preload of between 3 and 5 micrometers. One row of cylindrical rollers 16 sits on the shaft flange 7 and is guided laterally by the rib guide 26. The other cylindrical roller bearing 16 is arranged on the surface of the shaft 4.For lateral guidance of the cylindrical rollers, the rollers are distributed in a circumferential bearing groove of the shaft. A specially ground, rotatable cam ring 8 is arranged and supported on this roller bearing 16. The inner surface of the cam ring 8 follows a special curved design, as described in more detail in Figure 3. The outer surface of the cam ring 18 is designed with a coaxial curve to the inner curve and is supported by one or more highly preloaded row(s) of cylindrical rollers 15 in the bearing housing 18. This preload is up to 10 micrometers, and within this preload the coaxial cam ring 8 is designed to rotate. The cam ring 8 is connected to a rotor 19 of an internally arranged cam ring motor 21 and is rotated by this as required. The cam stroke occurs radially to the bearing. The stator 20 of the cam ring motor 21 is firmly connected to the bearing housing 18.A motor housing disk 25 is arranged on the cam ring motor 21, to which a cam ring measuring system 11 is attached, which measures the adjustment movement generated by the rotor and the cam ring measuring ring 24 coupled to it and makes it available for evaluation. A solid intermediate ring 22 is attached to the motor housing disk 25, to which the bearing housing ring 12 is firmly connected. Several measuring heads of a multi-dimensional, high-precision measuring system 9 are arranged on the bearing housing outer ring 12. The deviations from the concentricity and the shaft displacement of the shaft 4 are transmitted at the shaft end 5 via a shaft end measuring ring 10 arranged thereon to the measuring heads, which measure the deviations and make them available for evaluation. The measured results are used adaptively in real time to control the cam ring motor 21. The cam ring 8 is rotated radially up to a maximum of 180 degrees in one direction or the other from a zero position.This makes it possible to compensate for the deflection of shaft 4 caused by the applied machining forces. The cam ring motor 21, designed as a synchronous motor, is designed so that its holding torque, which is approximately 95% of its nominal torque, is sufficient to hold shaft 4 in the desired position.

[0030] Fig. 2 shows a simple design of a roller bearing unit 1 with manual adjustment. A number of plug-in bores 23 are arranged through the shaft 4. Plug-in pins 27 are inserted through these plug-in bores 23, with the aid of which the cam ring 8 can be radially adjusted. During adjustment, the shaft 4 is also rotated. The cam ring 8 is rotated relative to the bearing housing 18 in one direction or the other up to a maximum of 180 degrees, depending on the installed cam design and the measured values ​​determined by the multi-dimensional high-precision measuring system 9, whereby the concentricity can be considerably improved. In this sectional view in Figure 2, the section at the top is through the cylindrical rollers and the section at the bottom is placed exactly between the cylindrical rollers.

[0031] Fig. 3 schematically shows a preferred cam design for the cam ring 8 for two applications, which causes a tilting movement of the shaft 4 and thus compensates for the pendulum movement while the shaft 4 is driven by the direct drive 2. This cam design is particularly suitable, for example, for manual adjustment of the shaft 4 for trueness correction and a parallel displacement of the shaft 4 (as shown in Fig. 2). Starting from the zero point, there is initially a uniform curve rise of 5 micrometers from 28 to 45 degrees. This is followed by a cam stop 29 from 45 to 90 degrees, i.e. there is no further rise and thus no further deflection of the shaft 4 in this range. From 90 degrees, there is a further curve rise 30 by 2.5 micrometers to 7.5 micrometers. This results in a superimposed rotary movement of the direct drive 2.With the rotational movement of the direct drive 2, the cam motor 8 moves simultaneously, generating a 2.5 micrometer stroke, i.e., a tilting movement of the shaft 4 of 2.5 micrometers. These movements overlap. From 135 degrees to 180 degrees, a further curve rise 31 to 10 micrometers occurs. If the direct drive is braked or held in a controlled position, the cam motor 8 can displace the shaft 4 transversely while rotating (see explanations for Fig. 5).

[0032] In the second exemplary embodiment of the cam ring 8, a free cam profile 32 is shown according to individual customer-specific requirements with a curve profile of 5 to 10 micrometers. For every angle of rotation from 90 to 180 degrees, the stroke can be individually designed, resulting in a customer-specific transverse shaft movement or a combined rotary and tilting movement of the shaft 4. This range is therefore not a return stroke, but an active adjustment range that can be approached from both sides. At 180 degrees in position 33, a shaft displacement of a maximum of 10 micrometers occurs within the bearing preload, i.e. the shaft 4 is pressed into a type of circular ring with the set preload of 10 micrometers.

[0033] Fig. 4 shows a cross-section through a roller bearing unit in the area of ​​the cam ring 8. The cam ring 8 is designed on the outside with the same coaxial curve as the inner curve and is mounted in the bearing housing 18 with a row of cylindrical rollers 15. The row of cylindrical rollers 15 has a preload of up to approximately 10 micrometers. The cam ring 8 has the same coaxial curve on the inside and outside. In this figure, the preload 33 is shown as an empty space. As a result, the cam ring 8 is clamped both from the outside by the surface of the bearing housing 18 and from the inside by the surface of the shaft 4. This clamping means a considerable increase in rigidity down to the nanometer range in relation to the movement of the shaft 4 at the shaft end 5. In contrast, the axial rows of cylindrical rollers 14 and the radial rows of cylindrical rollers lö s are only slightly preloaded (3-5 micrometers), so that a targeted flexibility is created here.

[0034] Fig. 5 shows the linear movement of the shaft end 5 in space with the two different motors, the direct drive 2 and the cam motor 21. Due to the machining forces applied to the shaft end 5, for example, the output shaft, i.e. the shaft end 5, is deflected to the right. This deflection is measured by the multi-dimensional high-precision measuring system 9 using the shaft end measuring ring 9 connected to the shaft 4. These measurement results are adaptively transferred to the cam ring motor 21, which rotates the cam ring 8 radially and thus, through its cam design, causes an opposite deflection. The result of the method according to the invention is a precisely definable control width 34. This generates a specific tilting movement of the shaft 4 in the opposite direction.The control width 34 is created by the alternating control of direct drive 2 and cam motor 21, which are controlled during the deflection of the measuring ring and the adaptive control with a precisely defined natural frequency according to determined measured values ​​of the measuring system.

[0035] The compact roller bearing unit 1 with direct drive according to the invention can be used for rotary tables with high-precision axial / radial runout in the nanometer range for absorbing axial and radial loads, in particular in grinding and metrology.

[0036] List of reference symbols

[0037] 1 roller bearing unit

[0038] 2 direct drive

[0039] 3 engine housing

[0040] 4th wave

[0041] 5 Shaft end

[0042] 6 Wave collar

[0043] 7 Shaft flange

[0044] 8 Curve ring

[0045] 9 High-precision measuring system

[0046] 10 shaft end measuring ring

[0047] 11 Cam ring measuring system

[0048] 12 Bearing housing outer ring

[0049] 13 Thrust bearing shoulder

[0050] 14 axial cylindrical roller rows

[0051] 15 radial cylindrical roller rows (highly preloaded, single or double row)

[0052] 16 radial cylindrical roller rows for shaft bearings (lightly preloaded)

[0053] 17 Drive shaft

[0054] 18 bearing housings

[0055] 19 Rotor cam ring motor

[0056] 20 Stator cam ring motor

[0057] 21 Cam ring motor

[0058] 22 intermediate ring

[0059] 23 Plug-in hole

[0060] 24 cam ring measuring ring

[0061] 25 Engine housing disc

[0062] 26 On-board tour

[0063] 27 Plug-in pin

[0064] 28 curve rise 5 pm / 45 degrees

[0065] 29 Curve rest 45 degrees

[0066] 30 Curve rise 2.5 pm with superimposed rotational movement -45 degrees of

[0067] Direct drive tilting movement of the shaft with braked direct drive Free curve according to desired customer profile max. 10 pm shaft displacement within the bearing preload Control width of both motors / direct drive and curve motor

Claims

Patent claims:

1. Compact roller bearing unit (1) with direct drive (2) for rotary tables with high-precision axial / radial runout in the nanometer range for the absorption of axial and radial loads with at least one arranged multi-dimensional High-precision measuring system (9), characterized in that a multi-dimensional high-precision measuring system (9, 10) is arranged on a measuring system disk (12) at the shaft end (5) of a shaft (4), a cam ring measuring system (11) consisting of a cam ring measuring head and cam ring measuring ring (24), which is connected to a cam ring motor (21), is arranged on a motor housing disk (25), that the shaft (4) is mounted and guided directly in the bearing housing (18) of the roller bearing unit (1) without races via an additional specially ground cam ring (8) inside the roller bearing unit (1) and via one or more staggered radial cylindrical roller rows (15, 16), either as cylindrical roller rows or pairs of cylindrical roller rows, the shaft (4) is additionally mounted in an adjustable cam ring (8),the cam ring (8) is directly connected to a rotor (19) of a cam ring motor (21) arranged inside the bearing housing (18) and is designed to be rotatable, the cam ring motor (21) is fastened to the bearing housing (18), and / or the cam ring (8) is designed with an adjusting device that can be adjusted manually from the outside via one or more locking bores (23) by means of one or more locking pins (27), and the radial cylindrical roller rows (16) or radial cylindrical roller row pairs (16) and the cylindrical roller row for the cam ring outer bearing (15) are set with differently defined bearing preloads.

2. Compact roller bearing unit (1) according to claim 1, characterized in that the cam ring radii (26) of the cam ring (8) are staggered following a course of an individually adapted Archimedean spiral up to 180 degrees and then these are individually differently designed depending on the intended use.

3. Compact roller bearing unit (1) according to claim 1, characterized in that the cam ring 8 is formed with two complementary double curves and is mounted in the bearing housing (18) via two spaced-apart cylindrical roller rows (15).

4. Compact roller bearing unit (1) according to claim 1, characterized in that the bearing preload of the radial cylindrical roller row(s) (15) for the cam ring (8) is up to 10 micrometers and within this preload the coaxial cam ring (8) is designed to be rotatable.

5. Compact roller bearing unit (1) according to claim 1, characterized in that the bearing preload of the radial cylindrical roller rows (16) is set to a maximum of half a preload between 3 and 5 micrometers.

6. Compact roller bearing unit (1) according to claim 1, characterized in that the manually or motor-adjustable cam ring (8) is deformed or tensioned in the nanometer range in order to improve the inner diameter in its deviation from the circle (roundness) without restricting the overall rigidity.

7. Compact roller bearing unit (1) according to claim 1, characterized in that the cam ring is designed on the inner and outer diameter with a same coaxially aligned curve for adjustment in the nanometer or micrometer range.

8. Compact roller bearing unit (1) according to claim 1, characterized in that 4 to 8 measuring heads are distributed in the multi-dimensional high-precision measuring system (9).

9. Method for controlling the radial runout of a compact roller bearing unit (1), with direct drive (2) for rotary tables with high-precision axial / radial runout in the nanometer range for absorbing axial and radial loads with at least one arranged multi-dimensional high-precision measuring system (9), characterized in that the radial runout of a shaft (4) is measured and evaluated continuously or in a timed manner by one or more multi-dimensional high-precision measuring systems (9), that a cam ring (8) arranged inside the roller bearing unit (1) is automatically adjusted by a motor during the radial runout or when the shaft (4) is at a standstill, in a motor-controlled manner and / or manually, depending on the measured radial runout (oscillating movement) of the shaft (4), so that a type of high-precision positional movement takes place in space over the bearing center of the shaft (4).

10. Method for controlling the concentricity deviation of a compact roller bearing unit (1) according to claim 5, characterized in that both the motorized and the manual concentricity adjustment are provided and can be carried out in one and the same roller bearing unit (1).

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