Patent Application
20210107765
The invention generally relates to a rotary feed-through for at least one electrical, pneumatic and/or hydraulic line, such as cables, hoses or the like, which is to be guided between connecting points rotatable relative to each other about a rotational axis.
Endlessly rotatable rotary couplings for media or hose lines are known from the hydraulics and pneumatics sectors. For electrical power or signals, elements such as slip rings or slip contacts are sufficiently known for endless rotary transmission. Both solutions require an interruption of the line(s) in order to connect the interfaces on both sides to the coupling or the slip ring. In addition, rotary couplings for multiple, different operational media are technically complex.
The invention, on the other hand, relates specifically to a rotary feed-through for circular movements of at least one flexible line, in which the at least one line is uninterrupted but said movement is limited to a certain rotational angle. The invention thus relates in particular to a rotary feed-through which allows a possibly limited rotational angle without interruption of the line(s).
A system of this type is already known from the German patent DE 10 2012 110 967 B4. This system allows for winding and unwinding multiple lines, even for different media (electricity, data, gas, liquid, etc.)—without an interrupting rotary coupling—by means of a single drum. Therein, the drum has a winding core that is rotatable about the rotational axis with a conventional energy guide chain for guiding the lines. The inner end of the energy guide chain is fixed at the winding core. By turning the winding core, the energy guide chain is wound and unwound in the manner of a drum. Systems designed on the basis of the principle of DE 10 2012 110 967 B4 are marketed by the applicant (igus GmbH, D 51147 Cologne) under the trade name “e-spool”, and have proven themselves. In these systems, a special rotary guide is used to avoid the interruption of the lines typical for conventional solutions, e.g., according to patent EP 2 526 599 B1, with a ribbon-like line guide device, which guides the lines on a helical path with two helical layers wound in opposite directions. This special solution is available from the applicant under the trade name “twister-band”. This particular process—with helices or windings rotating in opposite directions and the turnover of the line(s) arranged between the two helical strands and moving axially between the same—makes it possible to use continuous lines, even across very large rotational angles, e.g., of several thousand degrees. Rotary feed-throughs according to DE 10 2012 110 967 B4 and EP 2 526 599 B1 are well-suited for small to medium cable diameters and chain loads or filling weights. However, a certain installation length is necessary in the axial direction, which increases with the desired rotational angle. The system is custom-made according to the desired rotational angle.
In contrast, the applicant has also developed a modular circular chain system, which it offers under the trade name “Multi Rotation Module (MRM)” (igus GmbH, D 51147 Cologne). The basic principle of such non-interrupting rotary feed-throughs is disclosed in the patent EP 2 732 519 B1 or U.S. Pat. No. 9,287,694 B2. Here, individual modules with circular guide channels are used, in which the energy guide chains move back and forth along a circular travel path while positioned on their sides.
For this purpose, RBR energy guide chains are required to allow for a close contact of the inner strand with the radial inner part of the guide channel. “RBR” stands for “reverse bending radius,” i.e., the energy guide chain can be angled in both pivot directions. The reverse radius (beyond the fully extended position) can be significantly larger than the normal radius or actual main radius in the deflection curve. A single MRM module according to the principle of EP 2 732 519 B1 or U.S. Pat. No. 9,287,694 B2 can achieve rotational angles of ≥540°. Thanks to the modular design, however, the rotational angles can be expanded almost indefinitely. The MRM system is ideal for high filling weights or chain loads. It is used in rotatable heavy machinery or systems, such as rotary cranes, bucket wheel excavators, mining stackers, wind turbines, etc. It typically has a diameter of at least 1,000 mm (always >>4-times normal chain radius) and is associated with a certain manufacturing and assembly complexity, due to the circular, special guide channels, among other factors.
Based on the above state of the art, there is a need for an uninterrupted rotary feed-through in a modularly expandable design, which is axially compact and/or is well suited for lower filling weights and/or line diameters.
One problem underlying the present invention therefore is to propose an alternative system for uninterrupted circular movements of at least one line that has a compact design, in particular with small axial dimensions, and which can be used in a modular manner. The solution should also be inexpensive to manufacture and/or easy to mount.
This problem is solved by a system or a rotary feed-through according to Claim 1 or independently thereof according to Claim 16.
A generic rotary feed-through for circular movements across a limited rotational angle is intended to guide at least one flexible line, such as a cable, hose, etc., between two connecting points rotatable relative to each other about a rotational axis without an interruption in said line. It comprises a first winding core rotatable about the rotational axis with a first energy guide chain for guiding the at least one line. The radial inner end of the energy guide chain therein is fixed at the winding core, in particular is pivotable, e.g., by a type of fastening at said end. By rotating the first winding core, the first energy guide chain is wound or unwound helically, corresponding to a planar helix, onto or from said winding core, depending on the rotational direction.
According to the invention, at least one second winding core is provided initially, which is axially adjacent to the first winding core, and which is arranged coaxially and rotatably, in particular rotatable relative to the first winding core, i.e., at least rotatable across a certain angle independently from it. In addition, the second winding core also has its own energy guide chain associated with it, referred to as the second energy guide chain, the inner end of which is fixed at the winding core. The second winding core, too, winds or unwinds the second energy guide chain helically, corresponding to a planar helix, depending on the rotational direction, equivalent in principle to the manner of the first winding core. This is either done in the same direction as in the first winding core, or preferably in the opposite rotational direction of the helical windings from the first to the second winding core. Therein, each winding core can be a single- or multi-component winding body.
Furthermore, a suitable connection is provided between the first energy guide chain and the second energy guide chain for feeding through the at least one line, which connection can, for example, also transfer the torque between the winding cores; however, the concrete design of said connection is not important in principle apart from its being able to guide a line. The connection may be provided between the two outer ends, or between an outer and an inner end of the energy guide chains.
The two energy guide chains in particular have a path similar to a spiral arm, which is coiled or wound more or less tightly around the respective winding core depending on the relative rotational position. Unlike in DE 10 2012 110 967 B4, the energy guide chain herein is not reeled on or off as if on a drum. Rather, the winding distance, similar to a helical spring, increases or decreases when winding or unwinding, but without a uniformity of the relative position and distances between helical windings or spiral arms (seen in the radial direction or in the axial cross-section) being of any importance.
In contrast to the solutions mentioned above, this solution neither requires the screw-shaped, double-helical path with the moving turning point, which requires much space in the axial direction, nor does it require special RBR energy guide chains or special guide channels.
The helical arrangement of the energy guide chains in multiple planes allows for very large rotational angles, e.g., well over 360° per winding core. The overall size initially scales radially with the selected or windable chain length. The maximum possible rotational angle per rotation plane or winding core is primarily dependent on the installable, windable chain length, which in turn is determined by the ratio of outer diameter to inner diameter of the available installation space. If the radial installation space is used completely, the rotational angle can be increased in small steps with each additional stage in the axial direction, e.g., a third, fourth, etc. winding core, if necessary. Thus, the proposed solution can be of a relatively compact axial design even at large rotational angles, e.g., >>1,000 degrees. In addition, smaller radii are possible than, for example, in the aforementioned MRM systems, depending on the desired rotational angle per module. A minimum diameter is specified in that the windings in their wound state lie on top of each other without space between the windings, and in that the number of windings depends on the desired chain length or the rotational angle per module. The required radial dimensions can accordingly be relatively compact, especially with small line diameters.
Each of the energy guide chains is arranged with its own plane of movement at a right angle to the rotational axis for the respective planar helical movement.
Depending on whether axially successive energy guide chains are wound onto the associated winding core in the same direction or not, the connection, which is provided for feeding through the at least one line between the successive energy guide chains, may either connect the radial outer end of the first energy guide chain with the radial inner end of the second energy guide chain, or may be provided between both radial outer ends of the first and second energy guide chains. The latter is a preferred design in combination with the opposite winding direction of both energy guide chains in one module.
The proposed design is preferably executed in a modular manner, wherein a module comprises at least one winding core, the energy guide chain fixed to it at its end and a connecting body for transferring rotational movement, and wherein multiple modules are used, which are of identical design and match each other. The connecting body may, for example, be attached in a rotationally fixed manner to the second winding core following it in the direction of the line, or include said second winding core as a component. A module can also comprise two winding cores, each with its own energy guide chain.
To simplify the modularity, the rotatable support of individual winding cores relative to each other and/or the line guidance, a preferred exemplary embodiment provides that at least one winding core has a central, axially continuous hollow cylindrical receptacle coaxially to the rotational axis. This receptacle preferably has a section with a circular cross-section and can thus interact with a rotating support counterpart for providing rotatable support, for example, on the axially adjacent winding core or connecting body. The receptacle can also be used for the line feed-through between individual modules. Preferably, both or all winding cores are identically designed, i.e., each has a central, hollow, cylindrical receptacle.
In particular in the latter design, a winding core arranged on the axial end can itself form one of the connecting points or be firmly connected to the same.
Preferably, all winding cores and all energy guide chains are identical in design. This increases the number of identical parts in the system, i.e., reduces manufacturing and inventory costs. Particularly preferably, the two energy guide chains have exactly one or only one predefined pivoting or curving direction, or both can be angled only in a predefined pivoting direction. These are therefore preferably not RBR chains.
In a particularly preferred embodiment, however, the winding direction is opposite in a module, or in two axially successive energy guide chains, i.e., the first energy guide chain and second energy guide chain extend helically around the associated winding core in opposite rotational directions, which is clearly recognizable at least when they are wound. Therein, it is preferable if the two radially outer ends, that is, those farthest away from the winding core, of the first and second energy guide chain are connected by means of a special connecting link for feeding through the at least one line. In this arrangement, a basic module consists of two winding cores and two energy guide chains, i.e., it is preferably to provide an even number of winding cores and energy guide chains.
The connecting link can preferably have respective joint halves on both sides, which are identical to a joint half of a chain link, wherein the joint halves are offset axially to each other by at least the chain width. In particular, identical energy guide chains in this manner can be solidly connected without further measures.
In particular, but not exclusively, in the preferred embodiment with windings in opposite directions, the rotational movement or torque can be transferred from the first winding core to the second winding core or vice versa by means of both energy guide chains. In other words, the force/torque transfer can be carried out within the module via both energy guide chains and, if necessary, the connecting link. Thus, no special gearing solution, rotary mechanism, guide channel coupling or the like is required. This simplified design is achieved in any case if the force and/or torque transfer is executed by means of the line guide device associated with the first winding core and/or by means of the line guide device associated with the second winding core. The energy guide chain is inherently suitable for this purpose due to its tensile/shear strength.
Alternatively, in particular in the case of windings not wound in opposite directions, the outer end of the first energy guide chain may be connected to the second winding core via a radially extended connecting body, for example, a type of turntable or a connecting arm. This also can be used to transfer rotational movement from the first winding core to the second winding core or vice versa by force transfer via the first energy guide chain and additionally via the connecting body. The connecting body can act as a lever arm and can be formed, for example, by a type of support disc. The advantage of a system with windings that are always wound in the same direction is that each group of winding core and energy guide chain forms a basic module, which means that a rotary feed-through can be easily created even with an odd number of winding stages. Energy guide chains also are inherently suitable for driving via a connecting body because of their typical stability in the longitudinal direction.
The force/torque transfer from one winding core to the next is therefore executed by means of an energy guide chain and, if necessary, other components.
It should also be noted that the proposed system is easily expandable in a modular manner, i.e., in particular a third winding core that is rotatable about the rotational axis with a third energy guide chain arranged in a correspondingly helical manner and preferably a fourth winding core rotatable about the rotational axis with a fourth energy guide chain arranged in a correspondingly helical manner may be provided. Preferably, all winding cores are coaxial and rotatable relative to each other and independently of each other, in particular at least across a certain rotational angle. All energy guide chains preferably take the aforementioned helical path similar to a spiral arm with increasingly narrow or expanding course, depending on the rotational position.
In the case of the preferred use of energy guide chains as line guide devices, all energy guide chains preferably are identical in design, in particular constructed from individual chain links pivotable relative to each other. This facilitates the manufacturing, mounting and, especially in the case of helical paths alternating in opposite directions, the connection of two chains due to joint halves of identical design.
It is possible to use energy guide chains preloaded into the fully extended position in the pivot direction, which corresponds to the rotational direction of the helix around the winding core. This allows also for transferring higher torques, if necessary, if the energy guide chains form a fully extended longitudinal section, especially in their fully unwound position. In particular in the case of link chains for guiding lines, it is advantageous if the first and second winding core, in particular all winding bodies, each comprise a connection area, which is designed for connecting the chain link at the inner end of the energy guide chain and for this purpose has a joint half of an identical design as a chain link of the energy guide chain. This makes it easier to use conventional energy guide chains.
The winding cores, in turn, preferably have an extensive contact surface on their outer side, as seen in the radial direction, for their respective associated energy guide chains, which contact surface is designed, starting from the connection area, to match the wound spiral shape—as seen in its radial cross-section—and in particular follows an archimedic spiral. This allows for a stable contact of the winding at the winding core in the wound position, which means uneven stress due to the constricting effect of the windings tightening on the winding core in this position can be avoided. The contact area in particular can have a steadily increasing radius. The initial radius should be larger than the normal deflection radius of the associated energy guide chain.
With regard to the dynamic process, the design is therefore preferably chosen such that each energy guide chain—in a fully wound position—makes contact with the winding core with most of its length, with windings positioned on top of each other without space between the windings. This can be achieved in particular if the energy guide chain extends according to an archimedic spiral or without space between its windings. On the other hand, the energy guide chains in a fully unwound position preferably extend about the rotational axis with most of their length in a manner corresponding to a circular arc pointing away from the winding core. For example, they can form a J-shape in plan view. Thus, most of their length can be in contact with an outer shell or a cylindrical outer wall and/or slide off the same, which supports, for example, the torque transfer in this position. A cantilevered, fully extended strand extends from the circular arc to the winding core, which strand can act like a lever arm. Between the two positions, the energy guide chains can extend similarly to a helical spring, i.e., like a tight, or wound further about the rotational axis, spiral arm, or with windings that “constrict” when being wound and “rise up” when being unwound.
Preferably, a housing with a cylindrical outer wall is provided, on which outer wall most of the length of a fully unwound energy guide chain is supported.
Preferably, the preferably identical winding cores in the middle range are designed as hollow cylinders in their central section, such that the winding cores can be arranged coaxially on a shared rotary shaft. Regardless of this, the connecting points, which are rotatable to each other, can be formed by the axially outer or end areas of two respective winding cores or be firmly connected to these.
Not exclusively, but especially in the case of line guide devices extending in opposite directions, an even number of groups of identical modules comprising at least one winding core with its associated energy guide chain is preferably provided
In one embodiment, a support disc may be provided as an axial separation between two respective, axially successive energy guide chains, in particular of two cascaded modules, which support disc is connected to a winding core or winding body in a rotationally fixed manner. The support disc may, if necessary, form a connecting body for transferring force or torque. A support disc may be provided, for example, between the first and the second winding core, or on only one of two winding cores of a module with two energy guide chains.
Conventional energy guide chains also are particularly suitable for the production of the proposed rotary feed-through. However, it is also conceivable to equip the proposed rotary feed-through with line guide devices in order to achieve circular movements across a limited rotational angle of a line between two connecting points rotatable relative to each other about a rotational axis, which line guide devices are not actual link chains, but, e.g., so-called conveyor chains, which are executed in one piece at least in sections.
The inventive idea, in particular according to Claim 16, can therefore be summarized as follows. A first winding core, rotatable about the rotational axis, is equipped with a first line guide device for guiding the line, which can be wound helically onto the first winding core or can be unwound from the same.
According to the invention, at least one second winding core with a second line guide device for guiding the line is provided axially adjacent to the first winding core. Furthermore, the second winding core is coaxial and rotatable about the rotational axis relative to the first winding core, in order to wind the second line guide device helically onto the second winding core or to unwind it from the same.
All embodiments shown above can be combined with Claim 16. The invention allows for a compact system that is easy to manufacture for providing uninterrupted lines for circular movements across a limited rotational angle by means of a rotary feed-through according to any one of the aforementioned exemplary embodiments. A significant advantage is that, in the final state, the at least one line is guided continuously, i.e., without interruption, from the first connecting point to the second connecting point through the rotary feed-through.
Further advantageous features of the invention are explained in more detail below—without constraining the generality of the statements above—on the basis of several preferred exemplary embodiments with reference to the attached drawings. The drawings show:
The basic module 10 comprises a first winding body or winding core 11a, which is rotatable about the rotational axis R, with a first energy guide chain 12a, the design of which is known in principle, which is fixed on the end side at the winding core 11a (see
Along the rotational axis R, axially adjacent to the first winding core 11a, the basic module 10 has a second winding core 11b, which here is designed identical to the first winding core 11a. An identical second energy guide chain 12b correspondingly is attached with its radial inner end 16b in a pivotable manner at the connection area 15 of the second winding core 11b. As
Both winding cores 11a, 11b are arranged coaxially and rotatable relative to each other with respect to the rotational axis R, and for this purpose are supported in an appropriate manner, e.g., on a rotary shaft (not shown). When the energy guide chains 12a, 12b are rotated relative to each other about the rotational axis R between a first, fully wound rotational end position (
The wound rotational end position in
The first winding core 11a, starting from the end position in
Both winding cores 11a, 11b have a circumferential cylindrical contact surface 13a on their outer side for supporting the respective energy guide chain 12a or 12b in the end position according to
As most easily visible in
Furthermore, the basic module 10, as shown in
In its unwound rotational end position (
Another difference is the connection between two pairs of axially successive modules 20A-20B, 20B-20C, etc. As
In
In the connection area or connecting body 27, the line(s) from the respective radially outer ends 18 of the cable carrier chain 12 of a module 20B or, respectively, 20C are guided radially inward to the rotational axis R and axially to the subsequent winding core 21 of the subsequent module 20A or 20B (indicated in
Within each module 20A, 20B, 20C, the first support disc 29a, which serves as a connection 27, can be rotated coaxially to the rotational axis R and relative to the respective winding core 21. To transfer rotational movement between modules 20A, 20B, 20C, the first support disc 29a can be connected to the winding core 21 of the respective axially adjacent next module 20A, 20B, 20C in a rotationally fixed manner, such that one module drives the respective next module and the rotation is transferred in steps or in the manner of cascade. Excluded from this is the first module 20A on the front, where the first support disc 29a forms a connecting point A or is attached to the same in a rotationally fixed manner. At the other axial end, for example, the winding core 21 of the last module 20C, for example, its inner receptacle 23b, can form the other connecting point B or be attached to the same in a rotationally fixed manner.
When the fully wound rotational position according to
Modules 20A-20C, as shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 20 2018 101 827.2 | Apr 2018 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2019/058437 | 4/3/2019 | WO | 00 |
