Motor shaft

Abstract

To provide a motor spindle 1 for driving a machining tool, comprising: a sleeve-shaped stator 2 extending along a stator axis 3, the stator having a first magnet system 9, a first coupling receptacle 11 and a second coupling receptacle 12; and a rotor 4, which has a rotor shaft 5 extending along a rotor axis 6, a second magnet system 10, a first coupling part 41 and a second coupling part 42; where the motor spindle allows precise and reproducible replacement of the rotor.SOLUTION: Along an entire displacement distance 14, there is a first distance 58 between a first axially facing surface 66 of an inner ring 62 and a second coupling part 42, and there is a second distance 59 between a second axially facing surface 67 of the inner ring 62, which is located on the side away from the first axially facing surface 66, and the second coupling part 42.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a motor main shaft for driving a machining tool, the motor main shaft comprising: a sleeve-shaped stator extending along a stator axis and having a first magnet system, a first coupling device holder, and a second coupling device holder; a rotor shaft extending along a rotor axis, and a second magnet system, a first coupling device part, and a second coupling device part, the first coupling device part being configured to be fixed to the first coupling device holder and being supported by the rotor so as to be rotatable about the rotor axis by a first rotation bearing configured as an axial fixed-side bearing; and the second coupling device part being fixed to the second coupling device holder. a motor main shaft supported on the rotor shaft for rotation about the rotor axis by a second rotary bearing configured as an axial free bearing, the second rotary bearing having an inner ring fixed on the rotor shaft and an outer ring arranged coaxially with respect to the inner ring and fixed to a second coupling part, the outer ring together with the inner ring defining an annular bearing gap in which a plurality of rolling elements are accommodated, the second coupling part being held on the rotor shaft for axial movement along a displacement distance parallel to the rotor axis between a first functional position and a second functional position. [Background technology]

[0002] German Patent Application No. DE 10 2011 116 703 A1 discloses a motor-driven machine tool unit, in particular a motor spindle, which comprises a rotor unit with a rotor shaft rotatable about a rotation axis, wherein, at least in the unassembled state, the rotor unit has at least one first bearing unit arranged in an end region of the tool holder and / or workpiece holder and a second bearing unit arranged in an oppositely oriented end region for supporting the rotor shaft in the stator unit in the assembled state, wherein the second bearing unit is configured as a free bearing for the rotor shaft and wherein at least one release device is provided for releasing the clamping of the free bearing in the assembled state. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] German Patent Application Publication No. 102011116703 Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is to provide a motor spindle that allows for highly accurate and reproducible replacement of the rotor. [Means for solving the problem]

[0005] This problem is solved by the motor main shaft of the aforementioned configuration with the features of claim 1. It is assumed that a first gap exists between the first axially facing surface of the inner ring and the second coupling part throughout the entire displacement distance, and a second gap exists between the second axially facing surface of the inner ring and the second coupling part, located on the side facing away from the first axially facing surface. Therefore, regardless of the relative position of the second coupling part, which is movable along the adjustment distance between the first and second functional positions, relative to the rotor shaft, a first gap or a second gap, defined by the first gap or the second gap, exists between the first axially facing surface of the inner ring and the second coupling part, and between the second axially facing surface of the inner ring and the coupling part, respectively. Both the first gap and the second gap always have values ​​greater than zero throughout the entire displacement distance. This characteristic ensures that, during operation of the motor main shaft, no contact occurs between the second coupling device part and the inner ring of the second rotary bearing, which could result in damage to the second rotary bearing, and further ensures that the second rotary bearing cannot be inadvertently disassembled with the rotor removed.

[0006] It is envisaged that in order to assemble the rotor in the stator, the first coupling device part is held in the first coupling device holder and fixed there, so that the first rotating bearing configured as an axial fixed side bearing ensures rotational support of the rotor shaft relative to the stator at the first bearing point.

[0007] It is envisaged that the second coupling device part, also referred to as a bearing sleeve, is fixed to the second coupling device holder, also referred to as a bearing seat, so that the second rotary bearing configured as a free axial bearing forms a second bearing point for the rotor shaft. The configuration of the first rotary bearing as a fixed axial bearing and the second rotary bearing as a free axial bearing ensures that thermal effects occurring during operation of the motor main shaft, which may lead to different expansions of the stator and the rotor, can be compensated for by displacements in the second rotary bearing, and that undesired forces are not introduced into the first and second rotary bearings.

[0008] For example, the first rotary bearing is configured as an assembly of a plurality of rolling bearings, preferably a plurality of ball bearings, in particular a plurality of angular contact ball bearings, in which case the rolling bearings can be arranged in an O-shaped arrangement, particularly preferably as angular contact ball bearings.

[0009] The second rotary bearing is configured as an axial free bearing, so that differential thermal expansion between the stator and the rotor can be compensated for by axial displacement of an inner ring fixed on the rotor shaft relative to an outer ring fixed on the second coupling part. In this case, the rolling elements arranged in the annular bearing gap between the inner and outer rings of the second rotary bearing are also adapted for relative axial movement between the inner and outer rings. Preferably, the displacement distance along the rotor axis of the second coupling part between the first and second functional positions is selected to be smaller than the maximum displacement distance, determined by the configuration of the second rotary bearing, that the outer ring can move relative to the inner ring before the rolling elements exit the bearing gap. Furthermore, the displacement distance with the safety margin is larger than the maximum differential expansion between the rotor and the stator that may occur during a specific operation of the motor main shaft.

[0010] It is preferred that the inner ring is formed with a cylindrical, or possibly conical, inner peripheral surface, and that its first axially-directed surface, which may be referred to as the first axial end surface, and its second axially-directed surface, which may be referred to as the second axial end surface, are each formed to be annular. It is particularly preferred that the first axially-directed surface is arranged in a first axially-directed plane aligned transversely to the rotor axis of the rotor shaft, and the second axially-directed surface is arranged in a second axially-directed plane also aligned transversely to the rotor axis of the rotor shaft, so that both axially-directed planes are aligned parallel to each other.

[0011] It is further assumed that both the first spacing between the first axially facing surface of the inner ring and the second coupling part and the second spacing between the second axially facing surface of the inner ring and the second coupling part are present throughout the entire displacement distance between the first and second functional positions, meaning that in the axial direction, with respect to both the first and second axially facing surfaces, there is always a first or second gap between the second coupling part and the inner ring, and therefore no contact between the second coupling part and the inner ring.

[0012] For example, it is envisaged that the second coupling device part is configured at least essentially rotationally symmetrical with respect to the rotor axis of the rotor shaft and has a U-shaped contour in a cross section including the rotor axis, whereby a circumferential groove opening radially inward is formed in which the outer ring of the second rotary bearing is held in a force-locking and / or form-locking manner.

[0013] Preferably, the coupling part is made up of two single annular parts which are axially connected to one another, allowing the outer ring to be accommodated in a circumferential groove.

[0014] Advantageous developments of the invention are the subject of the dependent claims.

[0015] Advantageously, the second coupling device part has at least one locking body recess formed on its outer surface, in particular recessed radially inward, and the second coupling device holder has a plurality of locking bodies on its inner circumferential surface, in particular arranged at a fixed angular interval, which locking bodies are adjustable between a release position, in particular located radially outward, and a locking position, in particular located radially inward, and are configured to engage in a form-locking manner with the locking body recesses in the locking position. Interaction between the at least one locking body belonging to the second coupling device holder of the stator and the locking body recess on the outer surface of the second coupling device part belonging to the rotor can result in a fixation of the second coupling device part in the second coupling device holder, in particular in the axial direction. Preferably, both coupling device holders and both coupling device parts are configured in such a way that the connection between the rotor and the stator is ensured by the locking body of the first coupling device part in the first coupling device holder and the locking body of the second coupling device part in the second coupling device holder. To this end, the at least one locking body or bodies can be advantageously adjusted between a radially outer release position and a radially inner locking position. It is preferably envisaged that, in the locked position, the at least one locking body or bodies can transmit a radially inward locking force, in particular directed toward the rotor axis of the rotor, from the second coupling device holder of the stator to the second coupling device part of the rotor. Particularly advantageously, due to the locking force exerted by each locking body, which may be referred to as a normal force at the second coupling device part, both a radially inward force component and a force component directed axially along the rotor axis are applied to the rotor. This ensures that the rotor is securely fixed to the stator both radially and axially.

[0016] It is preferably envisaged that in the locked position, the locking body abuts only against an inclined surface of the locking body recess, which is oriented at an acute angle with respect to the rotor axis, so that an axial locking force directed along the rotor axis toward the locked position is introduced from the second coupling device holder to the second coupling device part. The locking body recess can optionally be formed as a locally restricted hole or as a circumferentially extending groove on the outer circumferential surface of the second coupling device part. To ensure reliable locking of the rotor on the stator, it is important that the locking body recess has an inclined surface against which the locking body abuts in the locked position. In this case, the inclined surface may in particular coincide with the contact surface between the locking body and the locking body recess. It is important that the contact surface or the inclined surface must fulfill the condition that the contact surface or the inclined surface is oriented at an acute angle with respect to the rotor axis. Taking into account the tolerances to be taken into account for the geometry of the locking bodies, the inclined surfaces, the two coupling device holders and the associated coupling device parts, this can be advantageously achieved by the entire contact area, within which contact between the locking bodies and the locking body recesses is possible, forming an acute angle with the rotor axis. If the locking bodies are oriented radially inward toward the rotor axis and exert a locking force on the inclined surfaces that preferably extends transversely to the rotor axis, then depending on the orientation of the inclined surfaces, this locking force will be divided into a force component directed radially inward and another force component directed parallel to the rotor axis. This ensures the desired radial and axial locking of the rotor on the stator.

[0017] In an alternative embodiment of the locking bodies, the locking bodies are each adjustable along a locking path between a release position and a locking position, the locking path being oriented at an acute angle to the rotor axis. Preferably, in this case, the locking paths of the locking bodies accommodated in the second coupling device holder are arranged on a part-conically shaped envelope.

[0018] In another embodiment of the invention, the inner surface of the second coupling device holder and the outer surface of the second coupling device part are at least partially geometrically similar, in particular each formed in the shape of a partial conical flank, thereby ensuring a form-locking retention of the second coupling device part in the second coupling device holder in both the radial and rotor axis locking directions. This geometrical configuration of the second coupling device holder and the second coupling device part, on the one hand, allows for highly accurate centering of the second coupling device part relative to the second coupling device holder. On the other hand, the partially conical shape of the second coupling device part and the second coupling device part, respectively, facilitates an efficient disassembly of the second coupling device part from the second coupling device holder. This is because even a slight axial displacement of the second coupling device part relative to the second coupling device holder results in a complete separation of the opposing inner surface of the second coupling device holder and the outer surface of the second coupling device part. Preferably, the cone angle of the part-conical flank surface is set in the range of 17 to 19 degrees, which on the one hand achieves an advantageous centering effect between the second connector holder and the second connector part, and on the other hand prevents undesired self-locking.

[0019] In one embodiment of the present invention, a first linear stop is formed on the rotor shaft against which the second coupling part abuts in a first functional position, and a second linear stop is formed on the rotor shaft against which the second coupling part abuts in a second functional position. The role of the first and second linear stops is to limit axial sliding between the second coupling part and the outer ring of a second rotary bearing housed in the second coupling part to a predetermined displacement distance when the rotor is removed. In this case, the displacement distance is selected to ensure that the rolling elements of the second rotary bearing always remain within the bearing gap between the inner and outer rings. Furthermore, the displacement distance is selected so that any length change between the rotor and the stator does not cause the second coupling part to be displaced into either the first or second functional position. Therefore, the second coupling device part, the first linear stopper and the second linear stopper are adjusted relative to one another such that, in the state where the rotor is assembled in the stator, also referred to as the operating state of the motor main shaft, contact of the second coupling device part with both the first linear stopper and the second linear stopper is eliminated, taking into account all tolerances and length extensions of the individual components.

[0020] In one advantageous development of the invention, the second coupling device holder has a locking body guide that is displaceable relatively, in particular linearly, along the stator axis, the locking body guide having a guide cavity in which the locking body is accommodated so as to be displaceable transversely to the stator axis, the locking body guide being movably supported on a guide sleeve having a control surface that controls the movement of the locking body so that the relative movement of the locking body guide with respect to the guide sleeve results in a radial displacement of the locking body. Thus, the role of the locking body guide is, on the one hand, to ensure synchronization of the relative movement of the individual locking bodies, which are accommodated for this purpose in the guide cavity of the locking body guide. The guide cavity is dimensioned so that, when the locking body guide moves relative to the stator axis, the locking bodies move with at least little play and thus synchronously with the relative movement of the locking body guide. The radial positioning of the locking body is not effected by the guide cavity, but rather by a control surface against which the locking body preferably rests with its radially outer end region, the control surface being formed on the guide sleeve. The locking body guide is accommodated in the guide sleeve so as to be relatively movable, in particular linearly movable, so that a displacement of the locking body guide relative to the guide sleeve results in a rolling or sliding movement of the locking body guide along the control surface, which allows the radial position of the locking body to be changed.

[0021] Advantageously, the guide sleeve has an annular space open on one axial side, and the locking body guide is assigned an annular plunger that is axially movably and sealingly accommodated in the annular space, so that the annular space and the annular plunger define a variable-sized working space, thereby forming a fluid actuator for axially displacing the locking body guide and actuating the locking body. The annular space may also be referred to as a circumferentially extending groove in the guide sleeve, which has a first inner wall located radially inside, a second inner wall located radially outside and opposite the first inner wall, and an axially oriented annular bottom area, where the axially oriented opening of the annular groove is closed by a annular plunger realized with a square or rectangular cross section, for example. Together with the annular space, the annular plunger thus forms a variable-sized fluid working space that can be supplied with a pressurized fluid, in particular compressed air or hydraulic oil. This allows for a pressure-dependent increase in the working space with an axial relative movement of the annular plunger relative to the guide sleeve, during which the locking bodies accommodated in the guide cavities of the locking body guide are displaced at least radially or with a superimposed radial and axial relative movement depending on the configuration of the control surfaces formed on the guide sleeve, thereby locking or releasing the second coupling part.

[0022] In another embodiment of the present invention, the locking body guide is supported on the stator so as to be movable between a locked position relative to the second coupling part and an unlocked position relative to the second coupling part, and in the unlocked position, the locking body guide acts on a coupling area defined by an inner surface of the second coupling device holder and configured to accommodate the second coupling part, thereby displacing the second coupling part. The coupling area may be referred to as a spatial volume occupied by the second coupling part when the rotor is accommodated in the stator and the motor main shaft is in an operating state. In particular, the coupling area is defined radially outward by an inner surface of a closed ring belonging to the second coupling device holder and an inner surface of the locking body guide belonging to the second coupling device holder.

[0023] The locking body guide is configured to at least partially act on this coupling region in the unlocked position, so that when the locking body guide is moved from the locked position to the unlocked position, it can displace the second coupling part from the coupling region. This achieves that, when the second coupling part has already been unlocked by the locking body but static friction between the second coupling part and the second coupling holder still exists, the second coupling part is axially displaced by a predetermined amount by the relative movement of the locking body guide along the stator axis, thereby eliminating the static friction between the second coupling part and the second coupling holder. In particular, an axial force to be provided by a fluid actuator formed by the annular space in the guide sleeve and the annular plunger of the locking body guide is used for the unlocking operation.

[0024] In an advantageous development of the invention, at least one spring is assigned to the locking body guide, and the spring is configured to provide an axial force acting on the locking body guide toward the locked position. A single spring, or a set of several such springs arranged between the locking body guide and a support surface formed on the stator so as to be constantly preloaded, can ensure that the locking body guide is held in a favorable position that is identical to the locked position for the locking body guide when no pressure is applied to the fluid actuator. Therefore, a spring-preloaded locking body guide may be referred to as normally locked or normally closed. In this case, unlocking is achieved by applying pressure to the fluid actuator. The fluid actuator is dimensioned and supplied with pressurized fluid to provide the spring preload and the spring deformation energy required for axial displacement of the locking body guide.

[0025] Advantageously, the rolling elements of the second rolling bearing are configured as cylindrical rollers aligned parallel to the rotor axis, the inner ring of the second rolling bearing is provided with a circumferentially extending annular groove, the side walls of which are configured to guide the cylindrical rollers in the axial direction, and the outer ring of the second rolling bearing has a cylindrically formed inner surface against which the cylindrical rollers abut. This type of rolling bearing is also called a cylindrical roller bearing with a flangeless outer ring, and as an axially free bearing, it realizes a rolling bearing capable of supporting high loads for the second coupling part to the rotor shaft. In order to prevent undesired disassembly of this cylindrical roller bearing, the outer ring of the second rolling bearing is accommodated in the second coupling part, which is arranged along the rotor axis. No. The bearing is displaceable between one functional position and a second functional position, but the axial displacement is limited by the respective first and second linear stops so as to prevent the rolling elements from leaving the bearing gap between the inner and outer rings.

[0026] Advantageously, the outer surface of the second coupling part, together with the locking body recess, forms a displacement surface for the locking body, which is configured to displace the locking body radially outward when the locking body guide is displaced axially from the locked position to the unlocked position. The displacement surface is preferably matched to the locking body and to a control surface formed on the guide sleeve, so that a forced guide is obtained for the locking body, ensuring at least essentially predictable radial and axial positioning of each locking body at every axial position of the locking body guide relative to the guide sleeve. For example, an inclined surface defined by the locking body recess merges into the cylindrical outer surface of the second coupling part, which ensures a desired forced radial outward displacement of the locking body based on the geometry of the inclined surface when the second coupling part is displaced axially relative to the locking body, and subsequently ensures that the radially outward positioning of the locking body is secured by the cylindrical outer surface of the second coupling part.

[0027] Advantageously, the stator fitted with the first magnet system and the rotor fitted with the second magnet system form an electric motor from the group of synchronous motors and asynchronous motors, the first magnet system and the second magnet system each having at least one component from the group of magnetic coils, short-circuited coils and permanent magnets.

[0028] An advantageous embodiment of the invention is shown. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 2 is a schematic perspective view of a motor main shaft. [Figure 2] 2 shows a cross section of the motor main shaft according to FIG. 1, with the functional areas marked out diagrammatically. [Figure 3] 3 shows a cross-sectional view of the stator of the motor main shaft according to FIGS. 1 and 2; [Figure 4] 3 shows a cross-sectional view of a rotor for a motor main shaft according to FIGS. 1 and 2; [Figure 5]10 shows a partial cross-sectional view of a second coupling device holder in a locked position for a second coupling device portion of a rotor. [Figure 6] 6 shows a partial cross-sectional view according to FIG. 5 in the unlocked position of the second coupling part held in the second coupling holding part. [Figure 7] 6 shows a partial cross-sectional view according to FIG. 5 in the release position of the second coupling part held in the second coupling holding part. DETAILED DESCRIPTION OF THE INVENTION

[0030] The motor spindle 1 shown in Figures 1 and 2 is designed for use in a machining center and serves to clamp and rotate a cutting tool (not shown), such as a milling cutter. For connection to a motor spindle holder (not shown) of a machining center (also not shown), the motor spindle has a fixing ring 15. By means of the fixing ring 15, the motor spindle 1 can be attached to the motor spindle holder with high precision and / or reproducibility.

[0031] The motor main shaft 1 has a stator 2 configured in a sleeve-like manner, the substantially cylindrical geometry of which defines a stator axis 3. A rotor 4, shown in detail in FIG. 4, is rotatably accommodated in the stator 2. The rotor 4 has a rotor shaft 5, which is configured substantially tubular and extends along a rotor axis 6. As shown in FIG. 2, in the operating state, the rotor 4 is rotatably accommodated in the stator 2 such that the rotor axis 6 is identical to the stator axis 3.

[0032] The drawing in FIG. 2 is used merely as a schematic overview, in which all five different functional areas of the motor main shaft 1 are marked out symbolically within different dashed boxes.

[0033] The first functional area is defined by the first rotary bearing 7, which is essentially the axial fixed bearing.

[0034] The second functional area has a first magnet system 9 assigned to the stator 2 and a second magnet system 10 assigned to the rotor 4 and thus forms an electric motor core member of the motor shaft 1, since in this functional area the magnetic interaction between the first magnet system 9 and the second magnet system 10 results in the provision of torque to the rotor shaft 5.

[0035] The third functional area comprises the second rotary bearing 8 and will be explained in more detail below in connection with FIGS.

[0036] The fourth functional area comprises an actuator 16 configured to provide a linear movement directed along the rotor axis 6, which is introduced into a clamping device 17 arranged in the fifth functional area. The role of the clamping device 17 is to hold a cutting tool, not shown in detail, such as a milling cutter or drill, in a collet chuck 18. The collet chuck 18 is arranged on the rotor shaft 5 in the first functional area.

[0037] Thus, by using the motor shaft 1 to supply electrical energy to the first magnet system 9 and / or the second magnet system 10, a relative rotational movement of the rotor 4 with respect to the stator 2 can be introduced, whereby this rotational movement can be transmitted to a cutting tool (not shown) held in the collet chuck 18, by which, for example, a separating operation, in particular a milling operation or a drilling operation, can then be performed.

[0038] The stator 2, shown in detail in FIG. 3, has a tubular stator housing 20, which is rotationally symmetrical with respect to the stator axis 3, by way of example only. The stator housing 20 has a first coupling device holder 11 in a first end region and a second coupling device holder 12 in a second end region facing away from the first end region. By way of example only, the first coupling device holder 11 is realized as a stepped bore 21 having a plurality of cylindrically shaped bore sections. Two dowels 23, by way of example only, are arranged on an axially aligned end face 22 of the stepped bore 21. The dowels 23 are aligned parallel to the stator axis 3 and are provided for a rotationally fixed, centered retention of a first coupling device part 41 of the rotor 4, which will be described in more detail below in connection with FIG. 4.

[0039] The second coupling device holder 12, located in the second end region of the stator housing 20, has a closed loop 24 that is fixedly connected to the stator housing 20 in a manner not shown in detail. A guide sleeve 25 is fixed to the closed loop 24. A locking body guide 26 is linearly movably accommodated in the guide sleeve 25. The locking body guide 26 is held in a locking position, which will be described in more detail below, by a compression spring 27. For this purpose, the compression spring 27 is accommodated in a bore 28 drilled into the closed loop 24 on the end face side.

[0040] The rotor 4, shown in detail in Fig. 4, has a first rotary bearing 7 configured as a fixed axial bearing and a second rotary bearing 8 configured as a free axial bearing. In this case, the first rotary bearing 7 is assigned a first coupling part 41 that is intended for assembly into the first coupling holder 11. The second rotary bearing 8 has a second coupling part 42 that is intended for assembly into the second coupling holder 12 of the stator 2.

[0041] Between the first coupling part 41 and the rotor shaft 5, a first rolling bearing 7 is provided, which allows low-friction rolling movement of the rotor shaft 5 relative to the first coupling part 41. By way of example only, the first rolling bearing 7 comprises a first angular contact ball bearing 43 and a second angular contact ball bearing 44. Each of the angular contact ball bearings 43, 44 has an inner ring 45 fixed to the rotor shaft 5 and an outer ring 46 fixed to the first coupling part 41. A plurality of rolling elements 48, which are formed spherically by way of example only, are arranged in a bearing gap 47 between each inner ring 45 and each outer ring 46. The remaining components held in the first coupling part essentially serve to clamp the respective inner ring 45 or outer ring 46 and to ensure the sealing of the angular contact ball bearings 43, 44 and will not be described in detail below.

[0042] A second rotary bearing 8 is arranged on the rotor shaft 5 in an end region facing away from the first rotary bearing 7, and is configured as an axially free bearing, thereby preventing static instability or indeterminacy in the support of the rotor 4 in the stator 2. Furthermore, a second magnet system 10 is arranged on the rotor shaft 5 between the first rotary bearing 7 and the second rotary bearing 8. The second magnet system 10 can be, for example, a short-circuit coil, not shown in detail.

[0043] 5 to 7, the second rotary bearing 8 comprises, by way of example only, a cylindrical roller bearing 61. By means of the cylindrical roller bearing 61, the rotor shaft 5 is supported for free rotational movement relative to the second coupling device part 42.

[0044] The cylindrical roller bearing 61 has an inner ring 62 which with its inner peripheral surface 70 abuts against the outer peripheral surface 80 of the rotor shaft, and the inner ring 62 is fixed in position on the rotor shaft 5 by a support ring 81 supported on the rotor shaft 5, a compression sleeve 82 and a screw ring 83 threaded onto the rotor shaft 5. The outer ring 63 of the cylindrical roller bearing 61 is arranged coaxially with the inner ring 62 and the rotor axis 6 and is fixed to a second coupling part 42 which is made up of two parts by way of example only.

[0045] For example, the second coupling device part 42 has a first annular part 91 and a second annular part 92, where the first annular part 91 abuts with an axial end face 93 against an axial end face 94 of the second annular part 92 and is connected to the second annular part 92 by a plurality of axially aligned fastening screws 95. The first and second annular parts 91, 92, each configured rotationally symmetrically with respect to the rotor axis 6, define a circumferentially extending annular groove 96 that opens radially inward, and the outer ring 63 is received in the annular groove 96. For example, the geometries of the first annular part 91, the second annular part 92, and the outer ring 63 are adjusted relative to one another so that the outer ring 63 is form-fittingly received in the annular groove 96 both axially and radially.

[0046] A bearing gap 74 is formed between the inner ring 62 and the outer ring 63, and is defined on the radially inner side by a groove surface 71 of a groove 64 formed in the inner ring 62 and opening radially outward, and on the radially outer side by an inner circumferential surface 72 of the outer ring 63. A plurality of rolling elements 65 formed as cylindrical rollers are disposed in this bearing gap 74, and the rolling elements 65 roll against the groove surface 71 and the inner circumferential surface 72 of the outer ring 63 when the outer ring 63 rotates relative to the inner ring 62.

[0047] Furthermore, it is assumed that the inner peripheral surface 72 of the outer ring 63 is cylindrically formed, allowing axial displacement of the outer ring 63 relative to the rolling elements 65. Relative axial movement of the outer ring 63 relative to the inner ring 62 is limited by a first linear stopper 75 formed between the first annular portion 91 and the support ring 81, and a second linear stopper 76 formed between the second annular portion 92 and the compression sleeve 82.

[0048] For example, it is envisaged that the support ring 81 has an L-shaped contour in the cross-section according to Figures 5 to 7, in which case the contour provides an annular collar 84 protruding radially outwardly, positioned opposite the first ring portion 91, with an axially oriented stop surface against which the oppositely oriented axial end face 97 can abut in a first functional position (not shown) of the second connecting device part 42, thereby forming the first linear stop 75.

[0049] In a similar manner, the compression sleeve 82 is provided with a circumferentially extending annular collar 86, the stop surface 87 of which is formed towards the cylindrical roller bearing 61 and which faces the oppositely directed axial end surface of the second annular portion 92. 98 , which forms a second linear stop 76. Therefore, the displacement distance 14 of the second coupling device part 42 along the rotor axis 6 is limited by the first linear stop 75 and the second linear stop 76.

[0050] The outer diameters of the support ring 81 and the compression sleeve 82, not shown in detail, are adjusted to the inner diameters of the first ring portion 91 and the second ring portion 92, not shown, so that there is always a radially extending gap between the opposing components, so that no contact occurs between the support ring 81 and the first ring portion 91 or between the compression sleeve 82 and the second ring portion 92 during rotation of the rotor shaft 5 around the rotor axis 6.

[0051] 5 to 7, the second connector part 42 has an outer surface 50 that is at least partially conically shaped, and that is geometrically similar, in particular identical, to the inner conical surface 29 of the closed loop 24. Furthermore, the inner surface 29 of the closed loop 24, together with the inner surface 30 of the locking body guide 26, the support ring 81, and the compression sleeve 82, defines a connector region 31. The size of the connector region 31 can be reduced by axial displacement of the locking body guide 26, starting from the view of FIG. 5, as will be explained in more detail below.

[0052] For example, the locking body guide 26 has an annular support ring 32 which is joined axially along the stator axis 3 by a cylindrically formed locking body sleeve 33 which is itself connected to an annular plunger 34. In principle, the locking body guide 26 is a component which is rotationally symmetrical with respect to the stator axis 3; only the radially outwardly facing holes 35 in the locking body sleeve 33 which are provided to receive locking balls 36 used as locking bodies deviate from the rotationally symmetrical geometry of the locking body guide 26.

[0053] For example, it is envisaged that the annular plunger 34 is linearly displaceably and sealingly accommodated in an axial groove 37 of the guide sleeve 25, which is configured rotationally symmetrical with respect to the rotor axis 3, so that the annular space 38 defined by the axial groove 37 is available as a variable-sized working space 39. In this case, the size of the working space 39 depends on the axial position of the locking body guide 26 relative to the guide sleeve 25.

[0054] 5 to 7, when pressure is applied to the working space 39 and the resulting force acts on the axial end face 40 of the annular plunger 34, the locking body guide 26 is axially displaced from the locked position according to FIG. 5 to the unlocked position according to FIG. 7. During this displacement of the locking body guide 26 between the locked and unlocked positions, on the one hand, the compression spring 27 is compressed, thereby resulting in elastic deformation. On the other hand, the locking ball 36 is displaced axially along the stator axis 3, which results in an unlocking movement between the locking ball 36 and the second coupling part 42, as will be explained in more detail below.

[0055] 5, in the locked position, the exemplary illustrated locking ball 36 is received in a form-fitting manner between the cylindrically formed inner surface 51 of the guide sleeve 25, the corresponding bore 35 in the locking body sleeve 33 of the locking body guide 26, and the locking body recess 52 machined in the outer surface 50 of the second coupling part 42. This ensures a secure locking of the second coupling part 42 in the stator 2. In this locked position, a first gap 58 exists between the first annular part 91 and the oppositely arranged first axially facing surface 66 of the inner ring 62, and a second gap 59 exists between the second annular part 92 and the oppositely arranged second axially facing surface 67 of the inner ring 62.

[0056] When pressure is applied to the working space 39, the annular plunger 34 of the locking body guide 26, which is accommodated in the guide sleeve 25 so as to be axially and sealingly slidable, is displaced towards the first rotary bearing 7 as shown in FIG. 6 while the compression spring 27 is compressed. A radially outwardly directed withdrawal gap 53 opens between the support ring 32 and the guide sleeve 25 between an axially directed surface 55 of the guide sleeve 25 and an oppositely arranged axially directed surface 56 of the support ring 32. In order to allow the locking balls 36 to move radially outward before they can retract into the withdrawal gap 53, the transition region between the cylindrically formed inner surface 51 and the axially directed surface 55 of the guide sleeve 25 is provided with a chamfer 57, which is formed partly conically by way of example only. This chamfer 57 (also called a control surface) allows the locking balls 36 to be displaced radially outward already before the retraction gap 53 is fully opened.

[0057] Furthermore, the displacement of the locking balls 36 into the withdrawal gap is assisted by the geometric shape of the locking body recesses 52. The locking body recesses 52 are, by way of example only, machined into the outer surface 50 of the second coupling device part 42 as radially inwardly recessed grooves, and the locking body recesses 52 have groove walls 60 adapted to the geometric shape of the locking balls 36. For example, the groove walls 60 are configured with a quarter-circle contour, which, on the one hand, allows for a surface abutment of the locking balls 36 in the locked position, and, on the other hand, allows for the displacement of the locking balls 36 when the locking body guide 26 moves axially relative to the guide sleeve 25.

[0058] This displacement of the locking ball 36 releases the lock with the second coupling device part 42, allowing the rotor 4 to be removed from the stator 2 when a pulling force directed to the left in the drawing of Figure 6 is applied to the rotor 4.

[0059] However, it is typically assumed that in the locked state, the forces transmitted from the locking balls 36 to the second coupling part 42, particularly in the region of the groove wall 60, resulting in both axial and radial force components, result in significant static friction between the outer surface 50 of the second coupling part 42 and the inner surface 29 of the closure ring 24. This static friction is additionally increased by influences such as contamination and / or fretting, so that simple manual removal of the rotor 4 from the stator 2 is not anticipated. Therefore, to facilitate the removal of the rotor 4 from the stator 2, it is assumed that the locking body guide 26, which together with the guide sleeve 25 forms a fluid actuator, abuts against an end face 78 of the second coupling part 42, by way of example only, with an end face 77 formed on the annular plunger 34, before the maximum adjustment distance 79 of the locking body guide 26 is reached. Therefore, when the end face 77 of the annular plunger 34 abuts the end face 78 of the second connector part 42, a force is introduced from the locking body guide 26 to the second connector part 42, thereby allowing the second connector part 42 to be displaced from the locked position to the unlocked position, as shown in FIG. 7.

[0060] This results in an axial displacement of the second coupling device part 42 and the outer ring 63 housed inside the second coupling device part 42 relative to the inner ring 62 together with the rolling elements 65 held in the inner ring 62, the movement of the second coupling device part 42 being limited by the first linear stop 75 and the second linear stop 76 in relation to the rotor shaft 5 in such a way that the guiding of the rolling elements 65 by the outer ring 63 remains guaranteed at all times. Furthermore, the first annular part 91 and the second annular part 92 are adjusted to the inner ring 62 of the cylindrical roller bearing 61 in such a way that the first distance 58 and the second distance 59 are never zero or absent over the entire displacement distance 14, thereby ensuring problem-free operation of the rotor 4 even when removed outside the stator 2. The present application relates to the invention described in the claims, but also includes the following as other aspects. 1. A motor spindle (1) that drives a machining tool, a sleeve-shaped stator (2) extending along a stator axis (3) and having a first magnet system (9), a first coupling device holder (11), and a second coupling device holder (12); a rotor (4) having a rotor shaft (5) extending along a rotor axis (6), a second magnet system (10), a first coupling device part (41), and a second coupling device part (42); The first coupling device part (41) is configured to be fixed to the first coupling device holding part (11), and the rotor is rotatably supported about the rotor axis (6) by the first rotary bearing (7) configured as a fixed-side bearing in the axial direction. shaft a second coupling device part (42) configured to be fixed to a second coupling device holder (12) and supported on the rotor shaft (5) by a second rotary bearing (8) configured as an axial free bearing, the second rotary bearing (8) having an inner ring (62) fixed on the rotor shaft (5) and an outer ring (63) arranged coaxially with the inner ring (62) and fixed to the second coupling device part (42), the outer ring (63) together with the inner ring (62) defining an annular bearing gap (74), in which a plurality of rolling elements (65) are accommodated; the second coupling device part (42) being held on the rotor shaft (5) so as to be axially movable along a displacement distance (14) parallel to the rotor axis (6) between a first functional position and a second functional position; A motor main shaft (1), characterized in that a first gap (58) exists between a first axially facing surface (66) of the inner ring (62) and the second coupling device part (42) throughout the entire displacement distance (14), and a second gap (59) exists between a second axially facing surface (67) of the inner ring (62) located on the side away from the first axially facing surface (66) and the second coupling device part (42). 2. The motor main shaft (1) according to claim 1, characterized in that the outer surface (50) of the second coupling device part (42) is formed with at least one locking body recess (52), which is recessed particularly in the radial inward direction, and the second coupling device holding part (12) is provided with a plurality of locking bodies (36) on the inner circumferential surface (29), which are particularly arranged at a fixed angular pitch, and the locking bodies (36) are adjustable between a release position located particularly in the radial outward direction and a locking position located particularly in the radial inward direction, and in the locking position, are configured to engage in a form-locking manner with the locking body recess (52). 3. The motor main shaft (1) of the above two, characterized in that in the locked position, the locking body (36) abuts against, and in particular only against, the inclined surface (60) of the locking body recess (52), the inclined surface (60) being oriented at an acute angle with respect to the rotor axis (6), so that an axial locking force directed along the rotor axis (6) toward the locked position is introduced from the second coupling device holding portion (12) to the second coupling device part (42). 4. 4. The motor main shaft (1) according to claim 1, 2 or 3, characterized in that the inner surface (29) of the second coupling device holder and the outer surface (50) of the second coupling device part (42) are at least partially geometrically similar, in particular each formed in the form of a part-conical flank, so that a form-locking retention of the second coupling device part (42) in the second coupling device holder (12) is ensured in a locking direction directed both radially and along the rotor axis (6). 5. 5. The motor main shaft (1) according to any one of claims 1 to 4, characterized in that a first linear stop (75) is formed on the rotor shaft (5), against which the second coupling device part (42) abuts in the first functional position, and a second linear stop (76) is formed on the rotor shaft (5), against which the second coupling device part (42) abuts in the second functional position. 6. 6. The motor main shaft (1) according to any one of 1 to 5 above, characterized in that the second coupling device holding portion (12) has a locking body guide (26) that is relatively movable, in particular linearly movable, and displaceable along the stator axis (3), the locking body guide (26) is provided with a guide cavity (35), and the locking body (36) is accommodated in the guide cavity (35) so as to be movable laterally relative to the stator axis (3), the locking body guide (26) is movably supported by a guide sleeve (25), and the guide sleeve (25) is provided with a control surface (57), and the control surface (57) is configured to control movement of the locking body (36) so that relative movement of the locking body guide (26) with respect to the guide sleeve (25) causes displacement of the locking body (36) in the radial direction. 7. The motor main shaft (1) of claim 6, characterized in that the guide sleeve (25) has an annular space (38) that is open on one axial side, and the locking body guide (26) is assigned an annular plunger (34), which is accommodated in the annular space (38) with a sealing effect so as to be axially movable, so that the annular space (38) and the annular plunger (34) define a variable-sized working space (39), thereby forming a fluid actuator for axial displacement of the locking body guide (26) and actuation of the locking body (36). 8. The motor main shaft (1) of claim 7, wherein the locking body guide (26) is supported on the stator (2) so as to be movable between a locked position relative to the second coupling device part (42) and an unlocked position relative to the second coupling device part (42), and the locking body guide (26) acts on a coupling device area (31) configured to accommodate the second coupling device part (42), which is defined by the inner surfaces (29, 30) of the second coupling device holding part (12), in the unlocked position, thereby pushing away the second coupling device part (42). 9. 9. The motor main shaft (1) of claim 6, 7 or 8, characterized in that at least one spring (27) is assigned to the locking body guide (26), the spring (27) being configured to provide an axial force acting on the locking body guide (26) towards the locked position. 10. 10. The motor main shaft (1) according to any one of 1 to 9 above, characterized in that the rolling elements (65) of the second rotary bearing (8) are configured as cylindrical rollers aligned parallel to the rotor axis (6), the inner ring (62) of the second rotary bearing (8) is provided with an annular groove (64) extending in the circumferential direction, and the side wall of the annular groove (64) is configured to guide the cylindrical rollers in the axial direction, and the outer ring (63) of the second rotary bearing (8) has an inner surface (72) formed in a cylindrical shape, and the cylindrical rollers abut against the inner surface (72). 11. The motor main shaft (1) as described above, wherein the outer surface (50) of the second coupling device portion (42) forms, together with the locking body recess (52), a displacement surface for the locking body (36), and the displacement surface is configured to displace the locking body (36) radially outward when the locking body guide (26) is displaced axially from the locked position to the unlocked position. 12. The motor main shaft (1) of the above-mentioned item 1, characterized in that the stator (2) on which the first magnet system (9) is mounted and the rotor (4) on which the second magnet system (10) is mounted form an electric motor of the group consisting of synchronous motors and asynchronous motors, and the first magnet system (9) and the second magnet system (10) each have at least one component of the group consisting of magnetic coils, short-circuit coils, and permanent magnets.

Claims

1. A motor spindle (1) for driving a machining tool, a sleeve-shaped stator (2) extending along a stator axis (3) and having a first magnet system (9), a first coupling device holder (11) and a second coupling device holder (12); a rotor (4) having a rotor shaft (5) extending along a rotor axis (6), a second magnet system (10), a first coupling device part (41), and a second coupling device part (42); The first coupling device part (41) is configured to be fixed to the first coupling device holder (11) and is supported on the rotor shaft (5) by a first rotary bearing (7) configured as an axial fixed side bearing so as to be rotatable about the rotor axis (6), and the second coupling device part (42) is configured to be fixed to the second coupling device holder (12) and is supported on the rotor shaft (5) by a second rotary bearing (8) configured as an axial free side bearing so as to be rotatable about the rotor axis (6). a motor main shaft (1) having an inner ring (62) fixed on a rotor shaft (5) and an outer ring (43) arranged coaxially with the inner ring (62) and fixed to a second coupling device part (42), the outer ring (63) together with the inner ring (62) defining an annular bearing gap (74) in which a plurality of rolling elements (65) are accommodated; and the second coupling device part (42) being held on the rotor shaft (5) so as to be axially movable along a displacement distance (14) parallel to the rotor axis (6) between an unlocked position and a locked position, A motor main shaft (1), characterized in that a first gap (58) exists between a first axially facing surface (66) of the inner ring (62) and the second coupling device part (42) throughout the entire displacement distance (14), and a second gap (59) exists between a second axially facing surface (67) of the inner ring (62) located on a side away from the first axially facing surface (66) and the second coupling device part (42).

2. 2. The motor main shaft (1) according to claim 1, characterized in that the second coupling device part (42) has an outer surface (50) formed with at least one locking body recess (52), which is recessed, in particular radially inward, and the second coupling device holding part (12) has an inner circumferential surface (29) provided with a plurality of locking bodies (36), which are arranged, in particular at a fixed angular pitch, and the locking bodies (36) are adjustable between a release position, in particular located radially outward, and a locking position, in particular located radially inward, and in the locking position are configured to engage in a form-locking manner with the locking body recess (52).

3. 3. The motor main shaft (1) according to claim 2, characterized in that in the locked position the locking body (36) abuts against an inclined surface (60) of the locking body recess (52), in particular only there, the inclined surface (60) being oriented at an acute angle to the rotor axis (6), so that an axial locking force directed along the rotor axis (6) towards the locked position is introduced from the second coupling device holder (12) to the second coupling device part (42).

4. 4. The motor main shaft (1) according to claim 1, wherein the inner surface (29) of the second coupling device holder and the outer surface (50) of the second coupling device part (42) are at least partially geometrically similar, in particular each formed in the form of a part-conical flank, so that a form-locking retention of the second coupling device part (42) in the second coupling device holder (12) is ensured in a locking direction directed both radially and along the rotor axis (6).

5. 4. The motor main shaft (1) according to claim 1, wherein a first linear stop (75) is formed on the rotor shaft (5), against which the second coupling part (42) abuts in the unlocked position, and a second linear stop (76) is formed on the rotor shaft (5), against which the second coupling part (42) abuts in the locked position.

6. 2. The motor main shaft (1) according to claim 1, wherein the second coupling device holder (12) has a locking body guide (26) displaceable along the stator axis (3) so as to be relatively movable, in particular so as to be linearly movable, the locking body guide (26) is provided with a guide cavity (35) in which the locking body (36) is accommodated so as to be movable transversely to the stator axis (3), the locking body guide (26) is movably supported on a guide sleeve (25), the guide sleeve (25) is provided with a control surface (57), and the control surface (57) is configured to control the movement of the locking body (36) so that a relative movement of the locking body guide (26) with respect to the guide sleeve (25) results in a radial displacement of the locking body (36).

7. 7. The motor main shaft (1) according to claim 6, characterized in that the guide sleeve (25) has an annular space (38) that is open on one axial side, and the locking body guide (26) is assigned an annular plunger (34) that is accommodated in the annular space (38) in an axially movable and sealing manner, so that the annular space (38) and the annular plunger (34) define a variable-sized working space (39), thereby forming a fluid actuator for the axial displacement of the locking body guide (26) and the actuation of the locking body (36).

8. 8. The motor main shaft (1) according to claim 7, wherein the locking body guide (26) is supported on the stator (2) so as to be movable between a locked position relative to the second coupling device part (42) and an unlocked position relative to the second coupling device part (42), and wherein in the unlocked position the locking body guide (26) acts on a coupling device area (31) defined by the inner surface (29, 30) of the second coupling device holding part (12) and configured to receive the second coupling device part (42), thereby pushing away the second coupling device part (42).

9. 9. The motor main shaft (1) according to claim 6, wherein the locking body guide (26) is assigned at least one spring (27), which is configured to provide an axial force acting on the locking body guide (26) towards the locked position.

10. 4. The motor main shaft (1) according to claim 1, wherein the rolling elements (65) of the second rotary bearing (8) are configured as cylindrical rollers aligned parallel to the rotor axis (6), the inner ring (62) of the second rotary bearing (8) is provided with a circumferentially extending annular groove (64), the side walls of which are configured to guide the cylindrical rollers in the axial direction, and the outer ring (63) of the second rotary bearing (8) has a cylindrically formed inner surface (72) against which the cylindrical rollers abut.

11. 3. The motor main shaft (1) according to claim 2, wherein the outer surface (50) of the second coupling device part (42) together with the locking body recess (52) forms a displacement surface for the locking body (36), the displacement surface being configured to displace the locking body (36) radially outward when the locking body guide (26) is displaced axially from the locked position to the unlocked position.

12. 2. The motor main shaft (1) according to claim 1, characterized in that the stator (2) on which the first magnet system (9) is mounted and the rotor (4) on which the second magnet system (10) is mounted form an electric motor from the group of synchronous motors and asynchronous motors, and the first magnet system (9) and the second magnet system (10) each comprise at least one component from the group of magnetic coils, short-circuit coils and permanent magnets.

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