Cooling device for bearings, arrangement with a bearing and lathe

Abstract

Cooling device (1, 20, 25, 26, 28) for a bearing (21, 27) with a housing (2), wherein the housing (2) has a cylindrical recess (3) for receiving the bearing (21, 27), wherein the cylindrical recess (3) has a housing inner wall (7) with a cylindrical outer surface (6), wherein the inner wall of the housing (7) is surrounded by an outer wall (8), wherein the inner wall of the housing (7) and the outer wall (8) are connected to each other by side walls (10) so that a cavity (9) surrounding the inner wall of the housing (7) is formed, wherein the inner wall of the housing (7) is supported against the outer wall (8) by spaced-apart supports (11, 11a, 11b) which extend from the inner wall of the housing (7) to the outer wall (8), characterized by the fact that at least the inner housing wall (7), the supports (11, 11a, 11b) and the outer casing wall (8) are manufactured in one piece using an additive manufacturing process.

Description

[0001] The invention relates to a cooling device for a bearing according to the preamble of claim 1. It further relates to an arrangement with a bearing and a lathe with such a cooling device.

[0002] EP 1 002 965 A1 discloses a generic cooling device for a bearing, comprising a housing comprising an inner housing wall and an outer casing wall enclosing a cavity, wherein the inner housing wall is supported against the outer casing wall by spaced-apart supports extending from the inner housing wall to the outer casing wall.

[0003] EP 3 214 327 A1 describes a cooling device for a bearing in which a housing and a cooling jacket have cooling channels for supplying a cooling fluid.

[0004] A cooling device for spindle bearings is also known from GB 1 124 147 A. The spindle bearing is surrounded by a cylindrical shell which is provided with spiral circumferential grooves for a coolant.

[0005] A similar cooling device for a spindle is proposed in EP 3 112 714 A1 and in JP 2011- 167 799 A.

[0006] A bearing block for receiving a bearing for a roller is disclosed in DE 10 2016 224 761 A1. The bearing block has an integrated internal coolant channel and is designed as a solid cast body.

[0007] Another cooling device is known from EP 1 647 740 A1. It consists of a sleeve-like housing that surrounds a ball screw drive. A spiral cooling channel is provided inside the housing. A liquid coolant is moved spirally through the cooling channel from one end of the ball screw drive to the other. As a result, the coolant heats up. Consequently, one end of the ball screw drive is cooled more effectively than the other. Furthermore, the area between two adjacent spiral coils is cooled less effectively than another area in direct contact with the cooling channel.

[0008] German patent DE 10 2017 202 699 A1 discloses a ball screw drive with double-nut cooling. The double-nut cooling system is specifically adapted to a spindle of the ball screw drive with regard to its geometry. It is not universal.

[0009] The object of the invention is to eliminate the disadvantages of the prior art. In particular, a cooling device for a bearing is to be provided which is of simple construction and enables improved cooling. A further object of the invention is that the cooling device should be as universally applicable as possible. In addition, an arrangement with a bearing and a lathe with a bearing featuring improved cooling are to be provided.

[0010] This problem is solved by the features of claims 1, 14 and 16. Advantageous embodiments result from the features of the dependent claims.

[0011] According to the invention, it is proposed that at least the inner wall of the housing, the supports and the outer wall are manufactured in one piece using an additive manufacturing process.

[0012] The term "supports" is to be understood generally within the scope of the present invention. These are spaced-apart support elements that connect the inner wall of the housing to the outer wall or support the inner wall of the housing against the outer wall. The supports extend from the inner wall of the housing to the outer wall. Their direction of extension can be radial or oblique with respect to the cylindrical outer surface. In a section perpendicular to the direction of extension, the supports can have different shapes. The supports can be round, preferably circular or elliptical, angular, or elongated. They can also have a cross-sectional area that is, for example, streamlined in the manner of an airfoil profile.

[0013] The term "bearing" generally refers to rolling bearings, plain bearings or positioning devices, in particular linear positioning devices, for example ball screw drives or the like, which contain rolling elements.

[0014] Due to the support of the housing inner wall by spaced-apart supports as proposed according to the invention, a completely different flow pattern results for the cooling fluid flowing in the cavity: The cooling fluid is no longer bound to the long path of, for example, a spirally shaped cooling channel. According to the invention, it can flow significantly faster from a cooling inlet to a cooling outlet. A further outer surface of a bearing, adjacent to the cylindrical outer surface, can thus be cooled more effectively and uniformly.

[0015] According to the invention, at least the inner wall of the housing, the supports, and the outer wall are manufactured in one piece using an additive manufacturing process. For example, the cooling device can be manufactured at least partially using a 3D printer in which metal powder is welded layer by layer along predetermined paths using a laser or electron beam.

[0016] In an advantageous embodiment, the supports extend from the inner wall of the housing to the outer wall in a non-radial, inclined direction with respect to the cylindrical outer surface. The proposed inclination of the supports improves the shear strength of the inner wall of the housing relative to the outer wall under stresses, for example, in the circumferential or axial direction. Such stresses can occur, for instance, when a bearing mounted in the inner wall of the housing fails. The proposed inclination of the supports thus contributes to improved emergency running properties of a bearing mounted in the cooling device according to the invention.

[0017] The supports can be inclined at an angle in an axial plane with respect to the cylindrical outer surface. In particular, a first portion of the supports may extend in a first inclined direction along a first circumferential direction, and a second portion of the supports may extend in a second inclined direction opposite to the first. In this case, for example, adjacent supports may form the shape of a "V" or an inverted "V" along their circumference. This results in an overall truss-like structure of the supports.

[0018] In a further embodiment, it is also possible that, with respect to the cylindrical outer surface, a first part of the supports extends in a first radial plane in a first oblique direction and a second part of the supports extends in an adjacent second radial plane in a second oblique direction opposite to the first direction.

[0019] It is also possible that the supports extend within an axial or radial plane in the first and second oblique directions.

[0020] The supports can extend from the inner wall of the housing to the outer wall at an angle α of less than 90° and more than 45° with respect to a tangent to a circle formed by an axial section through the cylindrical outer surface. Here, the angle α refers to the "direction of extension" of the supports. It has been shown that the proposed angles α contribute particularly efficiently to increasing the shear strength of the inner wall of the housing relative to the surrounding wall.

[0021] In a further embodiment, it is proposed that the first and second parts of the supports each extend from the inner wall of the housing to the outer wall at the same angle α. This simplifies manufacturing.

[0022] The inner wall of the housing can have the form of a pipe section. The outer wall can be designed, at least partially, in the manner of another pipe section. In this case, the pipe section and the other pipe section are preferably arranged coaxially. This results in the cavity having the form of an annular gap in which the supports are received. In the proposed embodiment, the cooling device is designed, at least partially, in the manner of a sleeve. The outer wall can also form an outer wall of the housing.

[0023] In a further embodiment, the casing wall may also be surrounded by an outer housing wall. The outer housing wall may be designed to be structurally adapted for mounting the bearing in a device. For this purpose in particular, the housing may have at least one flat surface.

[0024] The casing wall and / or at least one of the side walls may have a first opening for supplying a cooling fluid and / or a second opening for draining a cooling fluid. The cooling fluid is preferably a liquid, for example oil, water, oil-water emulsions, or other suitable cooling fluids.

[0025] In an advantageous embodiment, the first and second openings for supplying and draining the cooling fluid extend from the flat surface to the cavity. That is, in this case, the connections for supplying and draining the cooling fluid are provided on the flat surface.

[0026] According to a further provision of the invention, an arrangement is proposed comprising a cooling device according to the invention and at least one bearing incorporated therein. Preferably, the bearing is designed as a rolling bearing.

[0027] According to a further provision of the invention, a lathe with a main spindle is proposed, wherein the main spindle is rotatably mounted by means of several bearings designed as rolling bearings, and wherein the rolling bearings are accommodated in at least one cooling device according to the invention. The proposed lathe enables particularly precise manufacturing of parts. Due to the proposed improved cooling of the rolling bearings, undesirable backlash of the main spindle can be minimized. This allows for improved manufacturing precision.

[0028] In one embodiment, the rolling bearings are positively engaged in the cylindrical recess. This enables particularly good heat dissipation from the rolling bearing. It is considered especially advantageous that several front rolling bearings are housed in a front cooling device and at least one rear rolling bearing is housed in a rear cooling device. The proposed embodiment allows for uniform cooling of all rolling bearings supporting the main spindle.

[0029] Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. They show: Fig. 1. A perspective view of the cooling device with ball screw drive, Fig. 2 a perspective view according to Fig. 1, where the cooling device is partially broken, Fig. 3 a perspective view of the cooling device, Fig. 4 a sectional view according to Fig. 3, Fig. 5 a partially broken perspective view of the cooling device according to the Fig. 1 to 4, Fig. 6 a schematic sectional view through another cooling device, Fig. 7a to e Sectional views through supports, Fig. 8 a sectional view through a cross slide of a lathe, Fig. 9 a perspective view of a second cooling device with a first bearing, Fig. 10 a perspective view according to Fig. 9, the cooling device being partially broken, Fig. 11 a perspective view of a partially broken-up third cooling device, Fig. 12 a perspective view of a fourth cooling device with third bearings included therein, Fig. 13 a perspective view according to Fig. 12, the third cooling device being partially broken open, Fig. 14 a perspective view of a partially broken fifth cooling device, Fig. 15 a schematic sectional view through the main spindle of a lathe.

[0030] The Fig. Figures 1 to 5 show a first cooling device, generally designated by reference numeral 1. The first cooling device 1 has a housing 2 in which there is a recess, here designed as a cylindrical recess 3. A ball screw nut 30 of a bearing, here designed as a ball screw drive 4, is received in the cylindrical recess 3, preferably in a form-fitting manner. Reference numeral 5 designates a spindle of the ball screw drive 4.

[0031] The cylindrical opening 3 has a cylindrical outer surface 6. The cylindrical outer surface 6 defines an inner housing wall 7. The inner housing wall 7 is surrounded by a casing wall 8, so that a cavity 9 is formed between the inner housing wall 7 and the casing wall 8. The cavity 9 is bounded by side walls 10. The side walls 10 run approximately perpendicular to an axis A (see Fig. 6) with respect to the cylindrical outer surface 6.

[0032] As is particularly evident from Fig. As is clearly evident from Figure 6, the inner wall 7 of the housing is supported against the outer wall 8 by supports 11. In this embodiment, the inner wall 7 of the housing is designed in the manner of a pipe section. The outer wall 8 is, at least partially, designed in the manner of another pipe section. The pipe sections are arranged coaxially with respect to axis A. Consequently, the cavity 9 has approximately the shape of an annular gap.

[0033] As from Fig. As can be seen from Figure 6, radial supports 11a can extend from the inner housing wall 7 in a radial direction R to the outer casing wall 8. According to another variant, however, it is also possible for inclined supports 11b to extend at an oblique angle with respect to a tangent T onto a circle resulting from an axial section through the cylindrical outer surface 6. The corresponding inclination direction is shown in Figure 6. Fig. 6 is denoted by the reference symbol S. An angle α with respect to the tangent T is conveniently less than 90° and more than 45°.

[0034] The supports 11 and 11a, 11b can have different geometries in a section perpendicular to their direction of extension. As can be seen from the Fig. As can be seen in Figures 7a to 7e, the supports 11 can be designed like columns with a circular cross-section. However, it is also possible that the supports 11 have a rectangular cross-section (see Figure 7a to 7e). Fig. 7b, c and e) exhibit or are elongated (see Fig. 7c and d).

[0035] The inclined supports 11b can be - as in Fig. As shown in Figure 6, the inclined supports 11b extend in a radial plane containing the radius in a first inclined direction S and a second inclined direction S'. The inclined supports 11b can also be inclined in an axial plane containing the axis A in a first inclined direction S and / or a second inclined direction S'. All variations are conceivable with regard to the arrangement and inclination.

[0036] As can be seen particularly from the Fig. 1 and Fig. As can be seen in Figure 3, the housing 2 has a flat surface 12a on an outer wall 12, which is box-shaped in this case. First openings 13 and second openings 14 for supplying and removing a cooling fluid are provided in the flat surface 12a. The openings 13 and 14 connect the flat surface 12a to the cavity 9.

[0037] As is particularly evident from Fig. As can be seen from 5, the cavity 9 can also be subdivided by a web 15 in such a way that the cooling fluid is forced in a predetermined direction in the cavity 9 from the first opening 13 to the second opening 14.

[0038] Fig. Figure 8 shows a sectional view through a lathe. Reference numeral 16 denotes an x-slide or cross slide, which is linearly movable back and forth on a bed slide 17 in an x-direction designated by reference numeral X. The bed slide 17 is oriented in a z-direction parallel to the axis of a (in Fig. The main spindle 29 (shown in Figure 15) is movable. The x-direction runs in the horizontal plane perpendicular to the z-direction. Reference numeral 18 denotes a servo motor, which is driven by the spindle 5. The ball screw nut 30 of the ball screw drive 4 engages in the spindle 5. The housing 2 of the first cooling device 1 is mounted with its flat surface 12a to a correspondingly designed flat counter-surface on the underside of the x-carriage 16. The openings 13 and 14 open into correspondingly arranged cooling channels 19, which are provided within the x-carriage 16. The x-carriage 16 and the first cooling device 1 can thus be cooled via the cooling channels 19.

[0039] Fig. Figure 9 shows a schematic sectional view through a second cooling device 20 with a first bearing 21 housed therein. In the second cooling device, the casing wall 8 essentially forms the outer housing wall. A flange 22 extends from the casing wall 8, or the outer housing wall. A radially circumferential shoulder 23 extends radially inwards from the cylindrical outer surface 6 of the inner housing wall 7, and the first bearing 21 is supported on this shoulder with its outer bearing race 24 (see Figure 9). Fig. 9). In the second cooling device, the first openings 13 and the second openings 14 are located in one side wall 10, which is adjacent to the flange 22.

[0040] As from Fig. As can be seen in Figure 10, the inclined supports 11b are inclined in the same direction in each radial plane, i.e., the inclined supports 11b are arranged parallel in each radial plane. In the adjacent radial plane, the inclination of the inclined supports 11b is opposite. This results in a particularly high strength of the inner housing wall 7 relative to the outer casing wall 8 against axially acting stress.

[0041] Fig. Figure 11 shows a partially broken perspective view of a third cooling device. Here, the first openings 13 and the second openings 14 are provided on a side wall 10, which is not adjacent to a flange.

[0042] The Fig. 12 and Fig. Figure 13 shows a fourth cooling device, number 26. As shown from Fig. As can be seen in Figure 12, the fourth cooling device 26 serves to accommodate several second bearings 27. In contrast to the second cooling device 20, the fourth cooling device 26 does not have a shoulder 23 on its cylindrical outer surface 6. The first openings 13 and the second openings 14 open towards the side wall 10, which is located away from the flange 22. Otherwise, the fourth cooling device 26 is designed similarly to the second cooling device.

[0043] Fig. Figure 14 shows a perspective view of a partially broken-open fifth cooling device 28. Here, the first openings 13 and the second openings 14 are provided on the side wall 10 which has the flange 22.

[0044] Fig.Figure 15 shows a schematic sectional view through the bearing arrangement of a main spindle 29 of a lathe. The main spindle 29 is rotatably mounted by means of a first bearing 21, which is positively engaged in the second cooling device 20. The first bearing 21 forms a rear bearing of the spindle bearing arrangement. The main spindle 29 is further rotatably mounted by means of a second bearing 27. The second bearing 27 is positively engaged in the fourth cooling device 26.

[0045] The proposed bearing arrangement for the main spindle 29 effectively maintains the first bearings 21 and the second bearings 27 at a predetermined temperature. This allows the main spindle 29 to operate backlash-free across a very wide speed and load range, enabling high-precision manufacturing of parts.

[0046] Apart from the bearing of a main spindle 29 in a lathe, the cooling device according to the invention can in particular also be used to cool the bearing of another main spindle or any spindle of a machine or system or a machine tool such as a milling machine. Reference symbol list 1 first cooling device 2 cases 3 cylindrical openings 4 ball screw drive 5 spindles 6 cylindrical outer surfaces 7 Housing inner wall 8 Enclosing wall 9 Cavity 10 side wall 11 support 11a radial support 11b inclined support 12 Housing outer wall 12a flat surface 13 first breakthrough 14 second breakthrough 15 Bridge 16 x-sled 17 bed sleds 18 servo motor 19 cooling channels 20 second cooling device 21 first camp 22 flange 23 Shoulder 24 outer bearing shell 25 third cooling device 26 fourth cooling device 27 second camp 28 fifth cooling device 29 Main spindle 30 ball screw nuts Axis R Radial direction S, S' oblique direction T tangent X x-direction α angle

Claims

[1] Cooling device (1, 20, 25, 26, 28) for a bearing (21, 27) with a housing (2), wherein the housing (2) has a cylindrical recess (3) for receiving the bearing (21, 27), wherein the cylindrical recess (3) has a housing inner wall (7) with a cylindrical outer surface (6), wherein the housing inner wall (7) is surrounded by a casing wall (8), wherein the housing inner wall (7) and the enclosing wall (8) are connected to one another by side walls (10), so that a cavity (9) surrounding the housing inner wall (7) is formed, wherein the housing inner wall (7) is supported against the casing wall (8) by spaced-apart supports (11, 11a, 11b) which extend from the housing inner wall (7) to the casing wall (8), characterized by , that at least the housing inner wall (7), the supports (11, 11a, 11b) and the enclosing wall (8) are manufactured in one piece by means of an additive process. [2] Cooling device (1, 20, 25, 26, 28) according to claim 1, wherein the supports (11, 11a, 11b) extend from the housing inner wall (7) to the enclosure wall (8) in a non-radial, oblique direction (S, S') with respect to the cylindrical outer surface (6). [3] Cooling device (1, 20, 25, 26, 28) according to claim 1 or 2, wherein the supports (11, 11a, 11b) are each inclined obliquely in an axial plane with respect to the cylindrical outer surface (6). [4] Cooling device (1, 20, 25, 26, 28) according to one of the preceding claims, wherein with respect to the cylindrical outer surface (6) a first part of the supports (11b) extends in a first circumferential direction in a first oblique direction (S) and a second part of the supports (11b) extends in a second circumferential direction in a second oblique direction (S') opposite to the first direction. [5] Cooling device (1, 20, 25, 26, 28) according to one of the preceding claims, wherein, with respect to the cylindrical outer surface (6), a first part of the supports (11b) extend in a first radial plane in a first oblique direction (S) and a second part of the supports (11b) extend in an adjacent second radial plane in a second oblique direction (S') opposite to the first direction. [6] Cooling device (1, 20, 25, 26, 28) according to one of the preceding claims, wherein the supports (11b) extend with respect to a tangent (T) to a circle resulting from an axial section through the cylindrical outer surface (6) at an angle (α) of less than 90° and more than 45° from the housing inner wall (7) to the casing wall (8). [7] Cooling device (1, 20, 25, 26, 28) according to claim 5 or 6, wherein the first and the second part of the supports (11b) each extend at the same angle (α) from the housing inner wall (7) to the casing wall (8). [8] Cooling device (1, 20, 25, 26, 28) according to one of the preceding claims, wherein the housing inner wall (7) has the shape of a pipe section. [9] Cooling device (1, 20, 25, 26, 28) according to one of the preceding claims, wherein the casing wall (8) is formed at least in sections in the manner of a pipe section. [10] Cooling device (1, 20, 25, 26, 28) according to one of the preceding claims, wherein the casing wall (8) forms a housing outer wall (12) or is surrounded by a housing outer wall (12). [11] Cooling device (1, 20, 25, 26, 28) according to one of the preceding claims, wherein the housing (2) has at least one flat surface (12a). [12] Cooling device (1, 20, 25, 26, 28) according to one of the preceding claims, wherein a first opening (13) for supplying a cooling fluid and / or a second opening (14) for discharging the cooling fluid is provided in the casing wall (8) and / or in at least one of the side walls (10). [13] Cooling device (1, 20, 25, 26, 28) according to claim 12, wherein the first openings (13) and the second openings (14) for supplying and discharging the cooling fluid extend from a flat surface (12a) of the housing (2) to the cavity (9). [14] Arrangement with a cooling device (1, 20, 25, 26, 28) according to one of the preceding claims and a bearing (21, 27) accommodated therein. [15] Arrangement according to claim 14, wherein the bearing (21, 27) is designed as a rolling bearing. [16] Lathe with a main spindle (29), wherein the main spindle (29) is rotatably supported by means of several bearings (21, 27) designed as rolling bearings, wherein the rolling bearings are accommodated in a cooling device (1, 20, 25, 26, 28) according to one of claims 1 to 13. [17] Lathe according to claim 16, wherein the rolling bearings are positively received in the cylindrical recess (3). [18] A lathe according to claim 16 or 17, wherein a plurality of front rolling bearings are accommodated in a front cooling device and at least one rear rolling bearing is accommodated in a rear cooling device.

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