Temperature-controlled spindle assembly with fluid inlet hose

Abstract

Spindle assembly for use with a nut (15), wherein a spindle (18) has at least one helically extending groove (12) on its outer circumferential surface with respect to a longitudinal axis (11), via which it can be brought into screw engagement with the nut (15), wherein the spindle (18) has a longitudinal bore (20) extending in the direction of the longitudinal axis (11) with a first and an opposing second bore end (21; 22), wherein the longitudinal bore (20) is closed at the second bore end (22), wherein a tubular insertion body (30) is arranged inside the longitudinal bore (20), which together with the longitudinal bore (20) defines a fluid flow path (40) having a first and a second path end (41; 42), each of which is arranged at the first bore end (21),wherein the fluid flow path (40) extends from the first path end (41) internally through the insertion body (30) to the second bore end (22) and further outwards along the insertion body (30) to the second path end (42), wherein a rotary feedthrough (50) is provided which has a first assembly (60) which is at least partially surrounded by a second assembly (70), wherein the first assembly (60) is fixedly connected to the spindle (18) at the first bore end (21), wherein the first assembly (60) is rotatably mounted on the second assembly (70) with respect to the longitudinal axis (11), wherein the second assembly (70) has a first fluid connection (71) which is fluidically connected to the first path end (41), wherein the second assembly (70) has a second fluid connection (72) which is fluidically connected to the second path end (42), characterized in that the insertion body (30) is in the form of a hose is made of plasticwhich is flexible enough that it can be brought into contact with an inner circumferential surface (23) of the longitudinal bore (20) at least in the area of ​​the second bore end (22).

Description

[0001] The invention relates to a spindle assembly according to the preamble of claim 1.

[0002] From JP 2002-295628A and EP 1 785 225 A1, a spindle assembly is known which is equipped with liquid cooling. The corresponding spindle is screwed into a nut. It has a longitudinal bore in which a tubular insertion element is installed, wherein the longitudinal bore and the insertion element together define a fluid flow path for the temperature control fluid such that both fluid connections can be arranged on a single rotary union.

[0003] An advantage of the present invention is that the tendency of the insertion body to vibrate is minimized, particularly when it is very long. Furthermore, it eliminates the need for a complex support for the end of the insertion body that faces away from the rotary feedthrough.

[0004] According to claim 1, it is proposed that the insertion element be designed in the form of a plastic tube, which is flexible enough to be brought into contact with an inner circumferential surface of the longitudinal bore, at least in the region of the second bore end. The inner circumferential surface of the longitudinal bore is preferably cylindrical with respect to the longitudinal axis. The cross-sectional area of ​​the insertion element is preferably defined by two concentric circles. The plastic is, for example, polyamide. Preferably, the tube is in contact with the inner circumferential surface of the longitudinal bore over at least 60% of its length. The longitudinal bore is preferably designed as a blind hole. In the case of particularly long spindles, the longitudinal bore can also be drilled from two opposite sides, with the second bore end being closed again, for example by means of a separate sealing piece.The second bore end is preferably located near an associated longitudinal end of the spindle. A gap is preferably provided between the insertion body and the second bore end. The temperature control fluid is preferably a liquid, most preferably containing water and / or oil.

[0005] The dependent claims specify advantageous further developments and improvements of the invention.

[0006] It is possible for the insertion body to be permanently connected to the second assembly. This embodiment is particularly simple and cost-effective. In particular, a simple rotary feedthrough can be used.

[0007] The second assembly may include a tube arranged concentrically to the longitudinal axis, with the insertion body attached to one end of the tube facing the spindle. The tube is preferably substantially rigid and substantially immobile relative to the rest of the second assembly. The first path end is preferably fluidically connected to the first fluid port via the tube. The insertion body is preferably installed inside the tube.

[0008] It may be provided that a separate first sliding ring is arranged between the first and second assemblies. This sliding ring has a flat first sliding surface oriented perpendicular to the longitudinal axis. The sliding ring effectively seals the contact point between the first and second assemblies against the escape of temperature control fluid. This contact point is subject to minimal wear. The sliding ring can be fixed to either the first or the second assembly, with its first sliding surface slidably against the other assembly. The sliding ring can be made of ceramic. The counter-sliding surface against which the first sliding surface rests is preferably made of hardened steel. This counter-sliding surface is preferably flat and oriented perpendicular to the longitudinal axis.

[0009] It can be designed so that the insertion body is rigidly connected to the first assembly. This prevents any relative rotation between the insertion body and the spindle, especially when the spindle is rotating. Consequently, wear on the insertion body is avoided.

[0010] The first assembly may comprise a main body and a separate connecting body, with the connecting body being rigidly installed between the spindle and the main body, and the insertion body being attached to the connecting body. The connecting body can cost-effectively provide the connection channels between the first and second path ends and the first and second fluid ports, respectively. This allows the use of a commercially available and therefore cost-effective rotary union.

[0011] It can be provided that a separate channel body is rigidly integrated within the connecting body, the channel body defining an inner channel and, together with the connecting body, defining an outer channel. The insertion body is rigidly connected to the channel body in such a way that the first path end is fluidically connected to the first fluid connection via the inner channel. Thus, the insertion body is rigidly connected to the first assembly, simultaneously establishing all desired fluid connections. The second path end is preferably fluidically connected to the second fluid connection via the outer channel. The inner channel is preferably arranged concentrically to the longitudinal axis, penetrating the channel body along its entire length in the direction of the longitudinal axis.

[0012] It can be provided that at least one separate second sliding ring is arranged between the first and second assemblies, which has a second sliding surface that is circularly cylindrical with respect to its longitudinal axis. The at least one second sliding ring seals the various fluid channels at the transition between the first and second assemblies. It is preferably fixed to the second assembly, with the second sliding surface facing radially inwards. Preferably, three second sliding rings are present. The second sliding rings preferably bear against a counter-sliding surface of the first assembly that is circularly cylindrical with respect to its longitudinal axis. This counter-sliding surface is preferably made of hardened steel. The at least one second sliding ring is preferably made of ceramic.

[0013] It can be provided that the spindle is rotatably mounted on a base assembly, with an anti-rotation device arranged between the base assembly and the second assembly, by which the second assembly is held against rotation about its longitudinal axis on the base assembly. Thus, the first and second fluid connections are fixed relative to the base assembly. The anti-rotation device preferably engages positively with both the second assembly and the base assembly. The anti-rotation device is preferably designed as a cylindrical pin or a screw.

[0014] A drive motor can be provided, which is connected to the spindle in the area of ​​the second bore end for rotary drive purposes. The drive motor is preferably an electric motor. The drive motor can be connected directly to the spindle for rotary drive purposes via a coupling. However, it is also conceivable that the drive motor is connected to the spindle for rotary drive purposes indirectly via a gearbox, for example, a gear drive or a toothed belt drive.

[0015] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or on their own, without leaving the scope of the present invention.

[0016] The invention is explained in more detail below with reference to the accompanying drawings. They show: Fig. 1 a side view of a spindle assembly according to a first embodiment of the invention; Fig. 2 a longitudinal section of the spindle assembly according to Fig. 1; and Fig. 3 a longitudinal section of a spindle assembly according to a second embodiment of the invention.

[0017] Fig. Figure 1 shows a side view of a spindle assembly 10 according to a first embodiment of the invention. The corresponding spindle 18 is elongated in the direction of a longitudinal axis 11, having at least one helical groove 12 on its outer circumferential surface with respect to the longitudinal axis 11. Fig. Figure 1 shows simplified representations of individual turns of the helical groove 12, which actually extends between the first and second rotary bearings 13; 14 over the entire length of the spindle 18. In this case, the groove 12 has a substantially semicircular cross-sectional shape, allowing it to engage with a nut 15, which is designed as a ball screw nut. However, the present invention is also applicable to spindles that are part of a roller screw drive, a planetary screw drive, or a sliding screw drive.

[0018] The spindle 18 is rotatably mounted on a base assembly 16 with respect to the longitudinal axis 11 by means of the first and second rotary bearings 13; 14, which are, for example, designed as radial roller bearings. The base assembly 16 can, for example, be the machine bed of a machine tool, in particular a lathe. On the in Fig. On the left side, the spindle 18 is connected to a (symbolically represented) drive motor 17 in a rotary drive connection. The drive motor 17 is preferably an electric motor. The rotary drive connection can be made directly via a coupling or indirectly via a gearbox, in particular a gear drive or a toothed belt drive.

[0019] On the side opposite the drive motor 17, the spindle 18 is provided with a rotary union 50. The rotary union 50 has a first and a second fluid connection 71; 72. Temperature control fluid is supplied via the first fluid connection 71, which is guided through the spindle 18 and discharged again at the second fluid connection 72. The temperature control fluid is preferably a liquid, most preferably containing water and / or oil. The primary purpose is to cool the spindle 18 so that the heat generated during operation is dissipated. In particular, the aim is to maintain the temperature of the spindle 18 essentially constant at a predetermined setpoint. This minimizes pitch variations of the helical groove 12, which are caused by heat-induced changes in the length of the spindle 18.

[0020] The rotary feedthrough 50 has a first assembly 60, which is partially surrounded by a second assembly 70. The first assembly 60 is fixedly connected to the spindle 18. The first assembly 60 is rotatably mounted on the second assembly 70 with respect to the longitudinal axis 11. An anti-rotation device 74 is provided between the second assembly 70 and the base assembly 16. This anti-rotation device is designed as a cylindrical pin, which engages positively at one end in a corresponding bore in the second assembly 70 and at the opposite end in a corresponding bore in the base assembly 16.

[0021] Fig. Figure 2 shows a longitudinal section of the spindle assembly 10. Fig. 1. The spindle 18 has a longitudinal bore 20 with a first and an opposing second bore end 21; 22. The longitudinal bore 20 is designed as a blind hole, so that the Fig. The second end of the bore 22 on the left is pre-closed. For particularly long spindles 18, the longitudinal bore 20 can also be drilled from two opposite sides, with the second end of the bore 22 closed again, for example by means of a separate sealing piece. The second end of the bore 22 is preferably located near the second rotary bearing (No. 14 in Fig. 1) arranged such that the longitudinal bore 20 extends substantially over the entire length of the spindle 18. The inner circumferential surface 23 of the longitudinal bore 20 is circularly cylindrical with respect to the longitudinal axis 11. At the first end 21 of the bore, the first assembly 60 of the rotary feedthrough 50 is screwed into the spindle 18. This assembly is rotatably mounted on the housing body 73 of the second assembly 70 with respect to the longitudinal axis 11 by means of the third rotary bearing 51, which is, for example, designed as a radial roller bearing. The first and the second fluid connections 71; 72 are each formed as bores in the housing body 73, which run transversely to the longitudinal axis 11. A tube 61 is fixedly installed in the housing body 73, which is arranged concentrically with respect to the longitudinal axis 11. The tube 61 is made, for example, of stainless steel, so that it is essentially rigid and consequently essentially immobile. The tube 61 is located at the Fig. The right end of the second assembly 70 is fluidically connected to the first fluid connection 71, specifically through corresponding channels in the housing body 73. At the opposite end, a tubular insertion element 30 is inserted into the tube 61 and firmly connected to it, for example by gluing and / or crimping. The insertion element 30 is thus firmly connected to the second assembly 70. Accordingly, relative movement occurs between the insertion element 30 and the spindle 18 when the spindle 18 rotates.

[0022] The insertion body 30 is designed in the form of a tube made of plastic, for example polyamide. It is therefore flexible, so that under the influence of gravity it bends until it rests against the inner circumferential surface 23 of the longitudinal bore 20. Furthermore, it should be taken into account that a tube is usually not perfectly straight, so that it is also pressed against the inner circumferential surface 23 by its own stiffness. Fig. 2. The insertion body rests only at its free end in the region of the second bore end 22 against the inner circumferential surface 23 of the longitudinal bore 20. Depending on the length and stiffness of the insertion body 30, a longer contact area may also result. The contact described above prevents the insertion body 30 from being subjected to excessive vibrations, for example, when the spindle 18 is excited to torsional bending vibrations due to its rotational movements. The vibration path of the insertion body 30 will never be greater than the vibration path of the spindle 18. In particular, there is no risk of the insertion body 30 oscillating back and forth between the opposing wall sections of the longitudinal bore 20.

[0023] The insertion body 30 extends almost the entire length of the longitudinal bore 20, leaving a gap towards the second bore end 22, which allows the passage of temperature control fluid. The insertion body 30, together with the longitudinal bore 20, defines a fluid flow path 40, which has a first and a second path end 41; 42, each located at the first bore end 21. The first path end 41 is fluidically connected to the first fluid connection 71 via the tube 61. The fluid flow path 40 extends from the first path end 41 internally through the insertion body 30 to the second bore end 22 and then further outwards along the insertion body 30 to the second path end 42.

[0024] The longitudinal bore 20 is continued in the main body 62 of the first assembly 60 essentially in alignment 68. A separate first sliding ring 80 is fixed to the end face of the main body 62. The first sliding ring 80 has a flat first sliding surface 81, which is oriented perpendicular to the longitudinal axis 11. The first sliding ring 80 is made, for example, of ceramic, and its first sliding surface 81 bears against a flat counter-sliding surface 95 on the housing body 73. The counter-sliding surface 95 is made, for example, of hardened steel. The first sliding surface 81 and the counter-sliding surface 95 are precisely matched to each other so that essentially no temperature control fluid can pass through, while still allowing for low-friction and low-wear sliding motion. The counter-sliding surface 95 can be formed on a separate component made of a different material than the housing body 73.In the flow direction after the first sliding ring 80, a channel 76 is arranged in the housing body 73, which is also aligned with the longitudinal bore 20 and which is fluidically connected to the second fluid connection 72. Thus, the second path end 42 is fluidically connected to the second fluid connection 72. The aforementioned tube 61 is arranged inside the channels 68 and 76.

[0025] Fig. Figure 3 shows a longitudinal section of a spindle assembly 10' according to a second embodiment of the invention. The second embodiment is identical to the first embodiment except for the differences described below, so that reference is made to the explanations in relation to the first embodiment. Fig. 1 and Fig. 2 is referred to. In the Fig. 1, Fig. 2 and Fig. 3 are identical or corresponding parts with the same reference numbers.

[0026] In contrast to the first embodiment, in the second embodiment the insertion body 30 is fixedly connected to the first assembly 60 of the rotary feedthrough 50. Therefore, no relative rotational movement occurs between the insertion body 30 and the spindle 18 when the spindle 18 rotates. The second embodiment is particularly suitable for applications where the spindle 18 rotates very quickly, as the first embodiment would be prone to wear on the insertion body 30.

[0027] The main body 62 of the first assembly 60 includes a first and a second channel 93; 94, which are arranged eccentrically to the longitudinal axis 11. The counter-sliding surface 95 on the main body 62 is cylindrical with respect to the longitudinal axis 11. Three second sliding rings 90, each with a second sliding surface 91, rest fluid-tight against this surface. The second sliding rings 90 are made, for example, of ceramic, while the counter-sliding surface 95 is made, for example, of hardened steel. The second sliding rings 90 are each firmly received in a corresponding groove in the main body 62 of the first assembly 60. An elastic sealing ring 92 is arranged between each second sliding ring 90 and its associated groove to provide a static seal and to eliminate any play that may be present. Between each pair of adjacent second sliding rings 90, an annular groove 75, circumferential around the longitudinal axis 11, is arranged in the housing body 73 of the second assembly 70.The first and second fluid ports 71; 72 each open into an associated groove 75, with the first and second channels 93; 94 each having an outlet opening opposite an associated groove 75. Thus, the first and second channels 93; 94 are fluidically connected to the first and second fluid ports 71; 72, respectively.

[0028] A separate connecting body 63 is arranged between the spindle 18 and the main body 62 of the first assembly 60, which firmly connects the aforementioned parts 18 and 62. In this case, the spindle 18 is clamped in a corresponding recess of the connecting body 63, although any other fixed connection, such as a screw connection or an adhesive connection, can be used at this point. At the opposite end, the connecting body 63 is screwed firmly and fluid-tight to the main body 62. The connecting body 63 has a through bore 96, which runs concentrically to the longitudinal axis 11. The second channel 94 opens directly into this bore 96. The first channel 93 is connected via a curved connecting hose 76 or a corresponding connecting tube to an inner channel 65 in a separate channel body 64. The inner channel 65 is arranged concentrically to the longitudinal axis 11.At the opposite end of the inner channel 65, the insertion body 30 is received in the inner channel 65. Thus, the first path end 41 in the insertion body 30 is fluidically connected to the first fluid connection 71 via the inner channel 65, the connecting hose 67 and the first channel 93.

[0029] The channel body 64 is firmly held in the bore 96 of the connecting body 63. For this purpose, it has two end flanges 97, each of which is penetrated by several flange bores 98 in the direction of the longitudinal axis 11. The flanges 97 abut the bore 96. The channel body 64, together with the bore 96, defines an annular outer channel 66 through which temperature control fluid can flow from the second path end 42 to the second channel 94.

[0030] The first rotary bearing 13 is arranged between the connecting body 63 and the base assembly 16, although it can also be arranged between the spindle 18 and the base assembly 16. The rotary feedthrough 50 has a third rotary bearing 51, which is designed, for example, as a radial roller bearing. Reference sign 10 Spindle assembly (first embodiment) 10' Spindle assembly (second embodiment) 11 Longitudinal axis 12 Nut 13 first pivot bearing 14 second pivot bearing 15 mother 16 Basic assembly 17 Drive motor 18 spindles 20 longitudinal bore 21 first borehole end 22 second borehole end 23 Inner circumferential surface of the longitudinal bore 30 insertion bodies 40 Fluid flow path 41 first path end 42 second path end 50 Rotary feedthrough 51 third pivot bearing 60 first assembly 61 pipe 62 Main body 63 Connecting bodies 64 channel bodies 65 inner canal 66 outer canal 67 Connecting hose 68 Canal aligned with the longitudinal axis 70 second assembly 71 first fluid connection 72 second fluid connection 73 Housing body 74 Anti-rotation device 75 Nut 76 Canal aligned with the longitudinal axis 80 first sliding ring 81 first sliding surface 90 second sliding ring 91 second sliding surface 92 Sealing ring 93 first channel 94 second channel 95 Counter-sliding surface 96 bore 97 flange 98 flange bore

Claims

[1] Spindle assembly for use with a nut (15), wherein a spindle (18) has at least one helically extending groove (12) on its outer circumferential surface with respect to a longitudinal axis (11), via which it can be brought into screw engagement with the nut (15), wherein the spindle (18) has a longitudinal bore (20) extending in the direction of the longitudinal axis (11) with a first and an opposite second bore end (21; 22), wherein the longitudinal bore (20) is closed at the second bore end (22), wherein a tubular insertion body (30) is arranged inside the longitudinal bore (20), which together with the longitudinal bore (20) defines a fluid flow path (40) which has a first and a second path end (41;42) having, each of which is arranged at the first bore end (21), wherein the fluid flow path (40) extends from the first path end (41) inwards through the insertion body (30) to the second bore end (22) and further outwards along the insertion body (30) to the second path end (42), wherein a rotary feedthrough (50) is provided which has a first assembly (60) which is at least partially surrounded by a second assembly (70), wherein the first assembly (60) is fixedly connected to the spindle (18) at the first bore end (21), wherein the first assembly (60) is rotatably mounted on the second assembly (70) with respect to the longitudinal axis (11), wherein the second assembly (70) has a first fluid connection (71) which is fluidically connected to the first path end (41), wherein the second assembly (70) has a second fluid connection (72) which is connected to the second path end (42) is fluidically connected; characterized by, that the insertion body (30) is designed in the form of a plastic tube which is flexible enough to be brought into contact with an inner circumferential surface (23) of the longitudinal bore (20) at least in the area of ​​the second bore end (22). [2] Spindle assembly according to claim 1, wherein the insertion body (30) is rigidly connected to the second assembly (70). [3] Spindle assembly according to claim 2, wherein the second assembly (70) comprises a tube (61) which is arranged concentrically to the longitudinal axis (11), wherein the insertion body (30) is attached to an end of the tube (61) which faces the spindle (18). [4] Spindle assembly according to claim 2 or 3, wherein a separate first sliding ring (80) is arranged between the first and the second assembly (60; 70), which has a flat first sliding surface (81) that is oriented perpendicular to the longitudinal axis (11). [5] Spindle assembly according to claim 1, wherein the insertion body (30) is rigidly connected to the first assembly (60). [6] Spindle assembly according to claim 5, wherein the first assembly comprises a main body (62) and a separate connecting body (63), wherein the connecting body (63) is fixedly installed between the spindle (18) and the main body (62), wherein the insertion body (30) is attached to the connecting body (63). [7] Spindle assembly according to claim 6, wherein a separate channel body (64) is firmly received in the connecting body (63), wherein the channel body (64) defines an inner channel (65), wherein together with the connecting body (63) it defines an outer channel (66), wherein the insertion body (30) is firmly connected to the channel body (64) in such a way that the first path end (41) is fluidically connected to the first fluid connection (71) via the inner channel (65). [8] Spindle assembly according to one of claims 5 to 7, wherein at least one separate second sliding ring (90) is arranged between the first and the second assembly (60; 70), which has a second sliding surface (91) which is circularly cylindrical with respect to the longitudinal axis (11). [9] Spindle assembly according to one of the preceding claims, wherein the spindle (18) is rotatably mounted on a base assembly (16), wherein an anti-rotation device (74) is arranged between the base assembly (16) and the second assembly (70), by which the second assembly (70) is held against rotation about the longitudinal axis (11) on the base assembly (16). [10] Spindle assembly according to one of the preceding claims, wherein a drive motor (17) is provided which is in rotary drive connection with the spindle (18) in the area of ​​the second bore end (22).

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