CN120941125A - Machine tool with variable bearing prestress - Google Patents
Machine tool with variable bearing prestressInfo
- Publication number
- CN120941125A CN120941125A CN202510612029.3A CN202510612029A CN120941125A CN 120941125 A CN120941125 A CN 120941125A CN 202510612029 A CN202510612029 A CN 202510612029A CN 120941125 A CN120941125 A CN 120941125A
- Authority
- CN
- China
- Prior art keywords
- pressure chamber
- machine tool
- pressure
- bearing
- inner ring
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C25/00—Bearings for exclusively rotary movement adjustable for wear or play
- F16C25/06—Ball or roller bearings
- F16C25/08—Ball or roller bearings self-adjusting
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- B23Q1/00—Members which are comprised in the general build-up of a form of machine, particularly relatively large fixed members
- B23Q1/70—Stationary or movable members for carrying working-spindles for attachment of tools or work
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C19/00—Bearings with rolling contact, for exclusively rotary movement
- F16C19/02—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows
- F16C19/14—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load
- F16C19/18—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load with two or more rows of balls
- F16C19/188—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for both radial and axial load with two or more rows of balls with at least one row for radial load in combination with at least one row for axial load
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C19/00—Bearings with rolling contact, for exclusively rotary movement
- F16C19/22—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings
- F16C19/34—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings for both radial and axial load
- F16C19/38—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings for both radial and axial load with two or more rows of rollers
- F16C19/381—Bearings with rolling contact, for exclusively rotary movement with bearing rollers essentially of the same size in one or more circular rows, e.g. needle bearings for both radial and axial load with two or more rows of rollers with at least one row for radial load in combination with at least one row for axial load
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C23/00—Bearings for exclusively rotary movement adjustable for aligning or positioning
- F16C23/06—Ball or roller bearings
- F16C23/08—Ball or roller bearings self-adjusting
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C2322/00—Apparatus used in shaping articles
- F16C2322/39—General buildup of machine tools, e.g. spindles, slides, actuators
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Support Of The Bearing (AREA)
- Rolling Contact Bearings (AREA)
Abstract
本发明涉及具有轴向‑径向‑轴承(2)的机床(1)，轴向‑径向‑轴承用于吸收在外圈(5)、内圈(4)和固定在内圈上的轴盘(6)之间的力和力矩，以支承旋转轴，旋转轴用于在运行中使工具或工件旋转，其中，设有填充有流体的压力腔室(12)并且压力腔室布置成，使得在为压力腔室(12)填充流体时提高轴承(2)中的预应力。
The present invention relates to a machine tool (1) having an axial-radial bearing (2) for absorbing forces and torques between an outer ring (5), an inner ring (4) and a shaft disc (6) fixed on the inner ring to support a rotating shaft for rotating a tool or workpiece during operation, wherein a pressure chamber (12) filled with fluid is provided and the pressure chamber is arranged such that the prestress in the bearing (2) is increased when the pressure chamber (12) is filled with fluid.
Description
Technical Field
The invention relates to a machine tool for five-axis machining with high machining speeds, comprising an axial-radial bearing designed as a rolling bearing, which is suitable for absorbing forces in the radial direction and for absorbing compressive and tensile forces in the axial direction, for absorbing forces and moments between an outer ring, an inner ring and a shaft disk fixed to the inner ring, for supporting a rotary shaft which, in operation, is used for rotating a tool or workpiece.
Background
In machine tools, units such as milling heads, machining heads, rotating shafts and rotary tables are used as tools and manufacturing aids, which enable workpieces to be machined with high speeds and precision and parts of components to be manufactured into components with complex geometries. The tools used for the respective workpieces generally vary with the different types of machine tools. Thus, the machine tool can be embodied, for example, as a milling machine or a lathe. The machine tool is characterized in that the tool and/or the workpiece perform a relative movement with respect to each other. In this context, it is in principle necessary to distinguish between a machining strategy of a stationary tool or workpiece and a machining strategy of a workpiece or tool moving relative thereto with respect to the movement of the tool and workpiece relative to one another. The relative movement of the tool and the workpiece and the rotary table carrying the workpiece is in principle effected via a rotation axis.
In this case, a basic precondition for the quality of the finished workpiece in terms of the achievable machining accuracy is that the workpiece and the tool and other manufacturing technology aids occupy precisely a predetermined position and hold it, for example, via a CNC machining strategy. Because of the high machining forces and moments that occur during machining, for example, the milling head or the rotary table and the rotary shaft/shaft guided thereto must be subjected to alternating and different machining forces and moments, large relative movements are not permitted in this case. The high variable flexibility of machine tools, especially via 5-axis machining, and the large number of possible machining strategies (including variable tool and workpiece orientation position changes) that result from this flexibility, also place greater demands on the positioning accuracy of the particular rotating shaft/axes that underlie the precision of machine tool operation that needs to be maintained.
Different strategies are studied in order to meet the requirements of higher position stability and positioning accuracy.
Thus, in joint machining (all axes are meshed, the axes are moved relative to each other and interpolated synchronously), the driver generates a tangential moment to maintain the position of the driven part of the machine tool. But this moment is not sufficient for many processes, so that the rotating shaft/shaft is fixed by the clamping means after positioning. The clamping device does not absorb kinetic energy and therefore does not involve braking. Instead, the clamping device produces a positionally stable tangential moment of resistance. Likewise, bearings and in particular axial-radial bearings are used in the guiding and supporting of the rotating shaft. The axial-radial bearing is designed in terms of technology for absorbing gravitational forces and tilting moments and is suitable for use at very high limit speeds. In this case, the bearing type has a very high stiffness and a low uniform friction torque profile at the same time as a high tilting stiffness. By adjusting the prestress of the bearing, the magnitude of the absorbable forces and moments can be adjusted within predetermined limits, for example, depending on the particular processing strategy or the particular material and its material properties.
In order to ensure a positionally stable tangential resistance moment, it is necessary, for example, for the clamping device, possibly the bearings and the rotating table plate to be coordinated with one another very precisely. This includes that the prestressing of the bearing in the axial direction or in the radial direction (axial prestressing/radial prestressing) can be used as an alternative or in addition to the clamping device and be set.
The limit of the prestress of the bearing for increasing the rotation axis/rotation axis is described here by the maximum value of the adjustable stiffness of the specific bearing. If the prestressing exceeds a certain value specific to the bearing, the rigidity of the bearing can only be increased slightly, while the friction in the bearing and the heat increase, which can cause damage to the bearing depending on the degree. The use of prestressing forces and elastic deformation of bearings by introducing adjusting shims or spacer rings to increase the prestressing path of the bearing is widely used in industrial environments.
Spindle prestressing for machine tools is known from the prior art described in document US 3620586 a. The invention provides a spindle support for a machine tool, which is adapted to apply a predetermined small prestressing force to the spindle bearing during high-speed operation and to apply a predetermined higher prestressing force during low-speed operation. The prestressing mechanism includes a pair of axially oriented, hydraulically operated pistons disposed on opposite sides of one of the outer bearing rings. The piston has a relatively narrow annular shape and does not protrude radially significantly above the bearing, thereby minimizing the space required in the main shaft housing. The outer circumference of each spindle bearing is provided with an annular groove through which a cooling liquid can be circulated to cool the bearing more effectively. These cooling grooves also enable the bearing to be mounted directly into the headstock housing without the need to mount the bearing in a cooling sleeve located therebetween, thereby achieving more accurate spindle support.
The clamping device can be embodied hydraulically, pneumatically, spring-loaded or electromechanically. The important criteria here are a preferential degree of freedom of position accuracy and a high tangential resistance moment. Hydraulic clamping devices are already on the market in the case of larger bore diameters. There are only a few solution providers on the market, such as Zimmer, kostyrka, etc., or a large number of rotating table manufacturers' own solutions. Typically, the bearing has a predetermined prestress due to its structure. But the prestress cannot be changed. Clamping devices exist which fix the rotating shaft only tangentially. This is advantageous for 5-axis machining.
But this would reach the technical limit in a 5-axis linkage process. The prior art currently makes a compromise between bearing prestressing and position adjustment in so-called torque motors or master-slave or gantry modes of operation in transmissions.
Thus, variable or dynamic adjustability of the bearing prestress according to the selected machining strategy is desirable. It is also significant to reduce the mechanical interface and reduce the installation effort. This can reduce costs.
In the machining of difficult-to-cut materials, advantageous effects can be achieved in terms of stability and machining accuracy of the rotating shaft by achieving a prestressing of the bearing guiding one of the rotating shaft/the rotating shaft.
Disclosure of Invention
Against this background, it is an object of the present invention to avoid or at least minimize the disadvantages known from the prior art.
This is achieved for tools of this type by filling the pressure chamber with a fluid and arranging the pressure chamber such that the prestress in the bearing is increased when the pressure chamber is filled with a fluid.
It can be said that the machine tool has at least one bearing provided with a variable prestress, which bearing is arranged to change the value of the prestress to a value different from the original/initial prestress value or to a value comparable to the original/initial prestress value when the prestress in the bearing decreases, for example, due to thermal expansion or expansion gradients of the part of the machine tool in operation and in particular of the at least one or more bearings and the rotating shaft guided through them. The prestressing force is used here to fix the rotary shaft of the machine tool and to fix the rotary shaft in its position during operation of the machine tool, which is used to guide and support components such as rotary tables, milling heads, spindles and the like. In this case, increasing the prestress in one or more bearings of the machine tool is a technical measure at least in addition to or instead of prior art solutions for fixing the rotational axis position. In this way, the clamping forces acting via the clamping device, such as a sleeve, on the rotary shaft or the tangential torques generated by the drive unit, acting counter to the operating forces and torques, or the control of the adjustment position of the transmission and the drive unit, are supplemented.
The solution according to the invention can therefore be summarized in that a variable prestressing force is introduced into the machine tool via the bearing in such a way that the clamping torque provided in the machine tool is adjusted for fixing and securing the shaft. According to the invention, the pressure chamber is here a central technical part of the machine tool for changing the prestress on one or more bearings.
Advantageous embodiments are set forth in the dependent claims and are explained in detail below.
The pressure chamber can be designed for receiving a liquid such as oil or a gaseous working medium such as air, compressed air or aerosol for hydraulic or pneumatic activation. By means of this design of the pressure chamber, it is advantageously possible in terms of technology to fill the pressure chamber with oil or another working medium via a pressure loading and supply system, which is preferably not provided in the bearing and is preferably pneumatic or hydraulic. The connection of the supply system and the respective pressure chamber is advantageously effected via a pressure line. The pressure chamber can be integrated in a cutting manner into a batch of parts of the bearing or can be integrated in the manufacturing technology simply during the manufacture of the bearing parts by casting technology or additive manufacturing technology. An advantageous embodiment of the pressure chamber provides a circumferential pressure chamber, wherein it is also conceivable to distribute a plurality of pressure chambers circumferentially at predetermined intervals. In the production of the pressure chamber, care should preferably be taken that the wall of the pressure chamber is sufficiently rigid or that the pressure chamber is surrounded by so much material volume that the pressure chamber is subjected to and fully absorbs the pressure of the inflow oil/other, in particular gaseous, working medium or the pressure of the oil/other, in particular gaseous, working medium located in the pressure chamber. This principle applies as long as no deformable or flexible wall part of the pressure chamber is required in the sense of the solution of the invention. The region for deformability or lower stiffness is important, as described in connection with other manifestations of the advantageous embodiments below. The pressure chamber realized in terms of manufacturing technology advantageously has at least one wall section with a low rigidity or an opening at least one point, preferably facing the raceway of the bearing. In a further description of the advantageous embodiment, an advantageous configuration of such an opening will be shown, which opening may be form-fitting, material-fitting or force-fitting closed.
As an embodiment of the pressure chamber described above, an oil/other and in particular gaseous working medium is advantageously accommodated in the pressure chamber for further preferably hydraulic or pneumatic activation. During operation of the machine tool and during its service life and in particular under static forces and moments, such as dynamic loads, it is advantageously necessary to ensure that oil/other and in particular gaseous working medium is accommodated by the pressure chamber.
In the invention shown, it is also advantageous if the pressure chamber is present in the inner ring or the outer ring and is supplied with working medium during operation via a pressure line to influence the pressure. By the arrangement of the pressure chambers in the inner and outer ring of the bearing, on the one hand, a structural freedom of the bearing position is advantageously achieved. On the other hand, the positioning of the pressure chambers in the inner ring or in the outer ring of the bearing enables the pressure chambers to have an influence on the different raceways of the bearing.
Furthermore, it is advantageous according to the invention if a pressure line is provided for supplying the pressure chamber with oil/another and in particular gaseous working medium, which pressure line enables a controlled flow of oil/another working medium into and out of the pressure chamber. In this connection, it is particularly advantageous if the volumetric flow/pressure of the oil/other working medium is specifically regulated in a predetermined manner in relation to the pressure line. In addition to the possible inflow, the outflow of oil/other working medium can also be advantageously achieved in order to adjust the preload in accordance with the forces and moments occurring during operation (including their maximum and minimum values) and the change in distance between the bearing individual component/bearings due to thermal expansion gradients. It is also advantageous in connection with the pressure line to guide the pressure line and to protect the pressure line from forces and moments acting during operation. An advantageous design of the guide is, for example, a through-hole or a built-in channel in the material of the bearing part. In the case of a guide of the pressure line designed as a free line or a free hose, care is advantageously taken to protect the line from tearing due to forces and moments occurring during operation.
Furthermore, it is advantageous if an insert disk, an annular piston or a bulge section on the outer ring, the inner ring or the shaft disk is provided in order to exert pressure on the raceways of the axial-radial bearing. Starting from a pressure chamber with a supply of oil/other working medium, pressure is applied to the adjoining material areas via a technical solution such as an annular piston and/or an annular disk/insert disk or deformable material section guided thereon or separately. The embodiment of the pressure chamber shown advantageously makes it possible to change the position of the annular piston/annular disk as a result of the inflowing oil/other working medium, so that the annular piston/annular disk/insert disk is pressed out/pushed out from the original position and occupies a new, advantageously predefined position. This means that in this embodiment the pressure chamber is open on the side facing the annular piston/annular disc/insert disc, so that the annular piston/annular disc/insert disc moves out of the pressure chamber and moves relative to the inner surface of the outer ring/inner ring/collar. By means of this relative movement, it is advantageously possible to apply pressure via surface contact to the adjoining material or part surface and to deform it preferably elastically. A further advantageous embodiment is also that no intermediate element, such as an annular piston/annular disk/insert disk, moves as a result of the pressure of the inflowing oil/other working medium, but rather the pressure acts directly on the wall of the pressure chamber with lower rigidity. In this embodiment, the lower stiffness is advantageously achieved via the arrangement in the region of the thickness and near surface of the material layer limiting the wall of the bearing/outer/inner ring part. The low stiffness and the resulting elastic deformability of the thin material wall advantageously enable the wall bulge phenomenon known for material diaphragms under the influence of pressure. Whereas the wall bulge is able to come into contact with the abutting surface and deform it preferably elastically. For both embodiments, it is advantageously and in principle conceivable that this is implemented in the outer ring and/or the inner ring and/or the shaft collar of the bearing or bearings. The so-called envelope of the associated ring is increased due to the bulge of the pressure chamber wall or the movement of the annular piston/annular disc/insert disc. The elastic deformation of the bearing raceways adjoining the pressure chambers and provided on the respective adjoining surfaces is achieved in a technically advantageous manner by elastic deformation of the surfaces adjoining the respective envelope surfaces of the respective rings. This means that the deformations due to the applied pressure of the oil/other, in particular gaseous, working medium are elastic and thus reversible.
It is furthermore advantageous to use a seal or seals to seal the pressure chamber. In this way, the pressure chamber can be sealed from the ambient medium and/or oil/other working medium located in the pressure chamber can be prevented from flowing out of the pressure chamber. The pressure in the pressure chamber is advantageously maintained by this embodiment. This is a core precondition for the solution according to the invention.
It is also advantageous if the direction of movement of the annular piston, the pressure disk, the insert disk or the bulge section is precisely predefined in the direction of the raceway. On the one hand, this embodiment advantageously achieves that no transverse forces occur on the raceways, which occur, for example, as a result of a dispersing action on the envelope region of the raised wall of the annular piston/annular disk/insert disk/pressure chamber. On the other hand, even deformation of the raceway due to the central action of the deforming pressure can be achieved via this embodiment. As a result of the elimination of unpredictable transverse forces, a targeted adjustment of the prestressing force to a predetermined value can be achieved. In this case, a precise adjustability of the prestressing force is of special technical significance, since excessive prestressing forces lead to irreversible bearing damage due to plastic deformation or to increased friction values and accompanying thermal damage. It is furthermore advantageously necessary to adjust for small changes in the prestress values, for example in relation to thermal expansion gradients of the bearing and the machine parts during operation. This is disadvantageously made difficult by the lateral forces that occur due to the dispersed stresses of the raceways. In this respect it has proved to be also advantageous to be able to check/verify the adjusted prestress value, preferably by means of force, displacement or friction values and suitable means, and to be able to compare it with calculated values.
It is also advantageous if the section of the inner ring for the bulge is designed as a membrane. The design of the wall section as a membrane, which is of low rigidity and elastically deformable, allows this section to bulge significantly and simply under a loading pressure which is lower than the pressure required to bulge the thin wall by means of a pressure loading, preferably by hydraulic or pneumatic means. The diaphragm is advantageously designed to perform the sealing function of the pressure chamber. Furthermore, the membrane is advantageously protected against damage during operation of the machine tool due to, for example, forces, moments, media and materials.
It has furthermore proved to be advantageous if the pressure chamber is closed off via a material connection between the ring closing off the pressure chamber and the inner ring. The above-described embodiments according to the invention are thereby provided for elastic deformation due to the thin walls of the pressure chamber or the bulge of the diaphragm. If, due to manufacturing technology and by taking into account costs and forces occurring during operation, a narrow gap cannot be achieved in the region of the thin wall/membrane, it is necessary to introduce a pressure chamber in the ring by means of a cutting process, to seal the pressure chamber by means of the ring/pressure element and to weld the pressure element on the outer surface of the ring. The supply line for the oil/other and in particular gaseous working medium can advantageously be realized by a supply line which leads through the inner ring of the bearing.
It is also advantageous if the position of the pressure disk, the annular piston, the insertion disk or the raised material wall can be reversibly changed by the inflow of the working medium. By means of complete reversibility, the bearings of the machine tool can be returned to their original state at any time. Furthermore, by means of this embodiment, it is also possible to assume a linear-elastic relationship for calculating the prestress of the bearing as a function of the pressure and/or the adjustment length and/or the force of the elastically deformable, preferably pneumatic or hydraulic, working medium, thereby reducing the calculation effort. Since the bearing is already prestressed in the original installed state, after the pressure drop, for example, the insert ring is pressed back into the original position again and the prestressing of the original structure is built up again.
In a special embodiment, the inflow of the working medium can be controlled in a targeted manner to generate a predetermined prestress. By controllable inflow into and outflow from the pressure chamber, the precondition is advantageously provided for this, that is, by using preferably basic physical and/or thermodynamic principles, the prestress of the bearing can be variably adjusted in a targeted manner.
The solution according to the invention for increasing the prestress presented by way of an embodiment of a machine tool can in principle be combined with other methods for fixing the position of a rotating shaft, for example a clamping device, a torque motor or a master-slave control of a transmission or a position control mechanism/bearing adjustment mechanism in gantry operation.
The embodiments shown can in principle be applied to axial bearings, axial-radial bearings, radial bearings and combinations of axial and radial bearings. The type of prestressing force achieved (axial and/or radial prestressing force) is determined by the direction of movement and the direction of pressure action/direction of increase of the envelope surface of the respective inventive solution. The applicability of the solution according to the invention has proved advantageous for rotary table bearing types of YRT (axial-radial (roller) bearing, bi-directional, screw-on), YRTC (axial-radial bearing, bi-directional, screw-on), YRTCMA (axial-radial bearing, bi-directional, screw-on, with integrated absolute angle measurement system), YRTCMI (axial/radial bearing, bi-directional, screw-on, with integrated incremental angle measurement ring/measurement system) and YRTCG and YRTCGMA (e.g. YRTCG, with integrated absolute angle measurement system).
Drawings
The invention is described in detail below with the aid of the figures. Two different embodiments of the invention are shown in detail herein. The attached drawings are as follows:
Fig. 1 shows a partial cross section of a rotationally symmetrical axial-radial-rolling-element bearing for the rotary shaft of a rotary table of a first embodiment of a machine tool according to the invention, wherein a hydraulically operated unit is provided in the outer ring of the bearing for increasing the prestressing force, and
Fig. 2 shows a partial cross section of a rotationally symmetrical axial-radial-rolling-element bearing for the rotary shaft of a rotary table of a further embodiment of a machine tool according to the invention, wherein a hydraulically operated unit is provided in the inner ring of the bearing for increasing the prestressing force.
Detailed Description
The drawings are merely schematic and serve only for understanding the invention. Like elements are provided with like reference numerals. Features of both embodiments can be substituted for each other or can be complementary to each other.
Fig. 1 shows a partial cross section of a first embodiment of a rotationally symmetrical axial-radial-rolling-element bearing 2 for a rotary shaft of a rotary table for a machine tool 1 according to the invention. The axial-radial bearing 2 is composed of an inner ring 4, an outer ring 5 and a shaft collar 6 from below upwards in the plane of the drawing and in the axial direction. In this case, each ring 4,5, 6 has an inner surface and an outer surface. The inner ring 4 and the collar 6 are force-connected and form-fit-connected and are arranged in a C-shape. In this case, the area enclosed by the C-shape represents the inner surface/inner face of the rings 4,5, 6. The outer surface 8 represents an outer region facing away from the inner surface.
The collar 6 is placed on the inner ring 4. The inner ring 4 has two regions of different diameters. With reference to the figure plane, below the collar 6 and in the region adjoining the collar 6 there is a region with a smaller diameter/inner diameter of the inner ring 4, followed by a lower region with a larger diameter/outer diameter of the inner ring 4. From a constructional point of view, a two-piece implementation of the inner ring 4 is basically conceivable. The outer ring 5 is arranged between the collar 6 and the lower region of the inner ring 4 having a larger diameter, with a distance from the inner ring 4 and the inner face/surface 7 of the collar 6. The outer ring 5 has a surrounding surface 9. The inner face/surface 7 of the inner ring 4 and the contact between the inner ring 4 and the surface 9 of the outer ring 5 and the outer ring 5 is achieved via the raceways 10 of the axial-radial-bearing 2 of the machine tool 1. The raceway 10 is positioned between the inner surface 7 of the collar 6 and the collar-side surface 9 of the outer ring 5, between the underside of the outer ring 5 and the underside of the region of the inner ring 4 having a larger diameter, and between the surface 9 of the outer ring 5 oriented in the radial direction towards the vertical wall of the inner ring 4 of the axial-radial-bearing 2 and a circumferential recess 11 provided in the wall of the inner ring 4. The raceway 10 includes rolling elements.
According to the invention, the outer ring 5 of the axial-radial bearing 2 comprises an blind recess, a so-called pressure chamber 12, the opening of which is located at the surface 9 of the outer ring 5 on the collar side. The recess/pressure chamber 12 has a predetermined width dimension in the radial direction and a predetermined depth dimension in the axial direction, wherein the dimensions can in principle be varied. In the embodiment shown, the recess is sized to accommodate the annular disc 13 and the annular piston 14, as well as the sealing ring 15 and the drain structure 16. A hydraulic supply line 17 is also provided, which leads a working medium, such as hydraulic oil or compressed air, via a production technique into the outer ring 5 and here into an annular region, preferably without fastening holes. according to the invention, the recess/pressure chamber 12 filled with the working medium, such as hydraulic oil, is sealed against the environment via a surrounding sealing element, such as a sealing ring, which is arranged below the annular disk 13 according to an embodiment, and prevents the working medium from coming out of the recess. To avoid oil leakage, a drain structure 16 is implemented below the annular piston 14. It is ensured that no oil layer is formed via the drain structure 16 on the underside of the insert ring/insert disc 13. According to the invention, the annular piston 14, which comprises the sealing ring 13, is moved in the axial direction as well as in the axial direction via a controlled inflow of working medium, such as hydraulic oil, until the sealing ring 13 occupies a predetermined position in the region of the rim-side surface 9 of the outer ring 5 or above the rim-side surface. According to the invention and according to an embodiment, this is accompanied by an increase in the surface 9 of the outer ring 5, whereby the raceway 10 is elastically deformed to a predetermined and calculated size. The initial prestress of the axial-radial bearing 2 of the machine tool 1 is changed and increased in the axial direction by this elastic deformation. By preferably reducing the volume and pressure of the working medium, such as hydraulic oil, the annular disk 13 is moved in the axial direction from above or below the position shown in fig. 1, the position currently occupied, to a position that can be adjusted in a targeted manner. In this way, the position of the annular disk 13 and the magnitude of the elastic deformation and the prestress of the bearing 2 can be varied in a targeted manner within a predetermined range, which determines the functionality of the bearing 2. In this case, according to the invention, the elastic deformation of the raceway 10 of the axial-radial bearing 2 of the machine tool 1 is completely reversible, so that no additional prestressing of the bearing 2 is provided for the position of the annular disk 13 below the raceway 10 of the axial-radial bearing 2 or in the plane of the surface 9 of the outer ring 5. According to the invention, the prestress can be set as a function of the prevailing, preferred working forces, thermal expansion during operation or other tangential resistance moment or control means applied by other means, such as clamping devices or drive units, and the initial setting of the bearing 2. According to the invention, the orientation and the direction of movement can be varied. Thus, a movement of the annular piston 14 and the annular disk 13 in the downward direction towards the lower raceway 10 of the inner ring 4 is conceivable as well as a movement direction in the radial direction and a radial prestress change/increase in the latter case. In addition to the annular piston 14 and the annular disk 13, the use of elements movable by the working medium is also conceivable according to the invention. In principle, the invention is also conceivable for axial bearings or for a combination of radial and axial bearings with or without a rolling element arrangement in the raceway 10. It can also be said that an advantageous embodiment can be summarized in relation to the outer ring 5 of the bearing 2 by placing an insert ring/insert disc 13 in the surrounding pressure chamber 12. Via a hydraulic supply line 17, a pressure builds up between the outer ring 5 and the insert ring 13. This moves the outer ring 5 and the insert ring/insert disc 13 away from each other. This results in an increased prestress in the axial direction in the bearing 2 of the machine tool 1.
Fig. 2 shows a bearing of the machine tool 1, which corresponds to the axial-radial bearing 2 described in fig. 1, which shows a second embodiment of the axial-radial bearing 2. Also shown is a partial cross section of a rotationally symmetrical axial-radial bearing 2 of a machine tool according to the invention. However, in comparison with the embodiment shown in fig. 1, the embodiment according to the invention shown relates to the inner ring 4 and in particular to the region of the inner ring 4 having a larger diameter.
The connecting element as inner ring 4 and shaft collar 6 arranged above it is preferably provided with screws 18 (see fig. 2). In principle, however, other embodiments of the connecting element can also be realized according to the idea and the invention. For the positioning of the screw 18, a hole 19 is shown in the axial direction through the inner ring 4 and the shaft collar 6 positioned thereon. The region of the inner ring 4 that includes the through-hole 19 is referred to as a wall 20 on the rotating shaft side of the axial-radial bearing 2. The holes 19 are embodied as fixing holes. A countersink 21 having a predetermined diameter and a predetermined depth is provided on the upper side of the collar to positively locate the head of the screw 18, whereby there is a larger diameter in the region of the countersink 21 than in the remainder of the bore 19. For the entire bearing 2, a plurality of such individual holes 19 are provided at predetermined intervals in the circumferential direction. The fastening holes 22 are likewise provided through and are introduced into the outer ring 5 at predetermined intervals in the circumferential direction in order to achieve the fastening of the fastening element to other structural elements in the machine tool 1. Below the raceway 10 for axial support is provided a recess/pressure chamber 12 in which a ring/pressure element 23 is located. The ring/pressure element 23 is smaller than the recess/pressure chamber 12 in the axial direction and is connected to the material and form-fittingly connected to the outer surface 8 of the inner ring 4. According to the embodiment shown, a weld is provided, which is realized such that the surface of the outer side 8 of the inner ring 4/ring/pressure element 23 forms a plane. Due to the smaller dimension of the ring/pressure element 23 in the axial direction, a free pressure chamber 12 in the sense of a pressure gap 24 is preferably formed in this way. The pressure gap 24 can be supplied with a working medium via the pressure line 17 in terms of production technology via a pressure inlet 25, wherein the working medium is preferably hydraulic fluid or compressed air, which can be introduced under pressure into the pressure gap 24. Preferably and according to the invention, the pressure gap 24 is sealed against other environmental media and is protected from loss of working medium by the weld 26 of the ring/pressure element 23. A maximum size of 0.5mm has proven to be technically advantageous for the size of the pressure gap 25. The pressure gap 24 is only slightly spaced from the inner surface 7 of the inner ring 4 below the raceway 10 in this region, so that the region of the inner ring 4 adjoining the raceway 10 is very narrow as seen in the axial direction. As a result of the narrow pressure gap 24, the pressure of the working medium causes an elastic bulge of the section 27 of the inner ring 4 for elastic bulge, so that the envelope surface of the inner ring 4 is increased and the adjacent raceways 10 are elastically deformed, while at the same time increasing the axial prestress of the bearing 2, which is preferred and is in accordance with the invention. Alternative arrangements and directions of movement of the elements as well as the technical aspects and the use of elements comparable to the working mechanism are also conceivable and possible in principle.
It is important in the case of the embodiment to understand that the pressure gap 24 in the sense of the pressure chamber 12 is realized in the inner ring 4 of the bearing 2, which is supplied with pressure via the hydraulic line 25 and into which the ring/pressure element 23 is placed, the pressure element can in principle be pneumatically controlled. The pressure chamber 12 is materially closed. The prestress is increased by increasing the oil pressure.
List of reference numerals
1. Machine tool
2. Axial-radial bearing/bearing
3. Rotary shaft
4. Inner ring
5. Outer ring
6. Shaft collar
7. Inner surface
8. Outer surface
9. Surface on the collar side
10. Raceway
11. Recess (es)
12. Pressure chamber
13. Annular disc/insert disc
14. Annular piston
15. Sealing element
16. Discharge structure
17. Supply line/pressure line for oil/other and in particular gaseous working medium
18. Screw bolt
19. Hole(s)
20. Wall portion
21. Countersink
22. Fixing hole
23. Ring/pressure element
24. Pressure gap
25. Pressure inlet
26. Welded part
27. Bump/material wall/section
Claims (10)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE102024113238.8 | 2024-05-13 | ||
| DE102024113238.8A DE102024113238A1 (en) | 2024-05-13 | 2024-05-13 | Machine tool with variable bearing preload |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN120941125A true CN120941125A (en) | 2025-11-14 |
Family
ID=97449813
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202510612029.3A Pending CN120941125A (en) | 2024-05-13 | 2025-05-13 | Machine tool with variable bearing prestress |
Country Status (2)
| Country | Link |
|---|---|
| CN (1) | CN120941125A (en) |
| DE (1) | DE102024113238A1 (en) |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1182931B (en) * | 1958-01-17 | 1964-12-03 | Skf Kugellagerfabriken Gmbh | Face plate bearings for vertical lathes and similar machines |
| US3620586A (en) * | 1970-02-12 | 1971-11-16 | Giddings & Lewis | Preload spindle bearing for machine tool |
| JPH05180220A (en) * | 1991-12-27 | 1993-07-20 | Nippei Toyama Corp | Bearing device |
| DE4227366A1 (en) * | 1992-08-19 | 1994-02-24 | Schaeffler Waelzlager Kg | Bearing with dampened vibrations esp. for machine tool - has two bearing elements rotatable relative to each other across at least one radial bearing and in at least one axial direction are located fixed to each other by axial bearing |
| DE19802566C2 (en) * | 1998-01-23 | 2003-12-24 | Fraunhofer Ges Forschung | bearing arrangement |
| JP5418110B2 (en) * | 2009-09-24 | 2014-02-19 | 株式会社ジェイテクト | Machine tool spindle equipment |
| DE102010035057A1 (en) * | 2010-08-21 | 2012-02-23 | Schaeffler Technologies Gmbh & Co. Kg | Adjustment for a rolling bearing and storage system with this adjustment |
-
2024
- 2024-05-13 DE DE102024113238.8A patent/DE102024113238A1/en active Pending
-
2025
- 2025-05-13 CN CN202510612029.3A patent/CN120941125A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE102024113238A1 (en) | 2025-11-13 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP5277057B2 (en) | Rotation resistance applying device in spindle drive device for machine tool | |
| US7942080B2 (en) | Index table assembly | |
| JP5117260B2 (en) | Rotational resistance device for spindle drive in machine tool | |
| US6505972B1 (en) | Bearing with adjustable setting | |
| CN110388889B (en) | Rotary table and roundness measuring machine | |
| KR20100100829A (en) | Rotation-indexing table apparatus for machine tool | |
| JP2014069210A5 (en) | ||
| JP2014069210A (en) | Tube processing method and shock absorber | |
| JP2012020378A (en) | Indexing device for machine tools | |
| JP3187153U (en) | Indexing board | |
| JP6524596B2 (en) | Bearing variable preload system for preload adjustment | |
| CN105339115A (en) | Main spindle device for machine tool and machine tool | |
| JP2000237902A (en) | Main shaft device | |
| CN120941125A (en) | Machine tool with variable bearing prestress | |
| JP3044196B2 (en) | Balance mechanism of driven body | |
| JP2011251385A (en) | Pre-load variable spindle | |
| JPH09257037A (en) | Spindle head for machine tool | |
| KR100878119B1 (en) | Air static pressure bearing device of high speed spindle for milling | |
| TW202430791A (en) | Rotation support device and shaft support device support mechanism position adjustment mechanism | |
| CN113236781B (en) | A sealing ring with anti-friction heat dissipation structure on the end surface and its processing method | |
| JPH0744425Y2 (en) | Rotary table | |
| KR20150050260A (en) | Spindle structure of machine tool | |
| CN103978235A (en) | Compact ring type radial high-accuracy locating and clamping mechanism and manufacturing method thereof | |
| CN109737141B (en) | Hydrostatic bearing module | |
| JPH11138304A (en) | Spindle device for machine tool |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication |